Executive Board Director and CEO Prof. Dr. André Anders Phone: +49 (0)341 235 - 2308 Fax: +49 (0)341 235 - 2313 E-Mail: andre.anders@iom-leipzig.de Leibniz-Institut für Oberflächenmodifizierung e.V. Leibniz Institute of Surface Engineering (IOM) Permoserstraße15 / 04318 Leipzig / Germany Phone: +49(0)341 235 - 2308 Fax: +49(0)341 235 - 2313 www.iom-leipzig.de ’inCathrinLiebner(

Organisational Structure

RECTOR OF THE LEIPZIG UNIVERSITY VISITS THE IOM / Prof. Dr. André Anders received the Rector of the Leipzig University, Prof. Dr. med. Beate A. Schücking at IOM in January 2018. Already since 1998, both institutions have maintained close cooperation relations, which are to be further intensified and sharpened with the visit of the Rector. The cooperation has a high priority for both institutions and is to be further expanded, especially in the areas of transfer, coordination of research activities and graduate training. In addition to the intensification of existing cooperation relations, both the joint development of new cooperation strategies and better networking of locations are of interest, especially with a view to further strengthening Leipzig as a research location and attracting excellent scientists to the region. AWARD OF THE SOMORJAI-MILLER-PROFESSORSHIP / Prof. Dr. Bernd Abel, Deputy Director of IOM and Professor of Technical Chemistry of Polymers at the University of Leipzig received a Somorjai Miller Visiting Professorship at the University of California in Berkeley in the winter semester 2018/19. The Gabor A. and Judith K. Somorjai Visiting Miller Professorship Award is announced annually by the Miller Institute for Basic Research in Science at UC Berkeley and is awarded to 1-2 internationally renowned scientists to initiate or intensify cooperation in the field of chemical sciences. AWARD OF THE KURT-SCHWABE PRIZE filters / Dr. Agnes Schulze received this prestigious award in 2018 for her outstanding development work on the subject of "Self-cleaning membrane for environmentally friendly use in water treatment". The Saxon Academy of Sciences in Leipzig has been awarding the Kurt-Schwabe Prize since 1983 in recognition of outstanding achievements in the natural sciences or technical sciences as well as outstanding personal services to the conservation of nature and its resources. Guido Werner

FORUM WISSENSCHAFTSMANAGEMENT LEIPZIG (FoWi) 2018 / At the new series of events "Forum Wissenschaftsmanagement Leipzig", questions and topics relating to administrative science management were addressed and discussed for the first time in a conference. Special focus was placed on the topics of personnel, research infrastructure, purchasing and finance. The aim of the event was to discuss current topics and debates on the management of innovative and successful science institutions and to jointly organized by the Deutsches present action and optimisation concepts. The conference was Biomasseforschungszentrum gemeinnützige GmbH (DBFZ), the Helmholtz Centre for Environmental Research (UFZ), the Leibniz Institute for Tropospheric Research (TROPOS) and the Leibniz Institute of Surface Engineering (IOM). „LANGE NACHT DER WISSENSCHAFTEN“ AND „GIRLS`DAY“ AT THE IOM IN APRIL AND JUNE 2018 / The IOM regularly participates in these activities and offers visitors the opportunity to learn more about our research institution. For this purpose, insights into selected high-tech laboratories are given and different research topics of the IOM are presented by staff members. “”

COMPETENCE REGION GRAVOMER - KICK-OFF MEETING AT THE IOM / The BMBF-funded alliance "GRAVOMER - Competence Region Microstructured Functional Surfaces" started the implementation phase with a kick-off meeting in September 2019. The event brought together players from various Central German companies and from educational and research institutions. The meeting was organized by the initial partners herlac Coswig GmbH, Sächsische Walzengravur GmbH and IOM and took place at IOM in Leipzig. The common goal of the 42 alliance partners is to anchor the competence network for the application- oriented design of surfaces on an industrial scale in the region and to increase its regional and international visibility for the benefit of the partners. GRAVOmer is one of 20 East German alliances that successfully passed the two-stage selection procedure of the programme "WIR! – Wandel durch Innovation in der Region". IOM JUNIOR SCIENTISTS AT THE LAUNCH CONFERENCE "SCIENCE FOR FUTURE" 2019 IN BEIJING / As part of the bilateral cooperation between the National Academy of Sciences Leopoldina and the Chinese Academy of Sciences (CAS), the Leopoldina and the Leibniz Association supported the participation of selected young scientists in the German-Chinese conference "Science for Future - All Starts with Basic Research", including Dr. M. Ehrhardt from the IOM. Excellent scientists, among them the two Nobel Prize winners in physics Prof. Dr. Klaus von Klitzing and Prof. Dr. Cheng Ning Yang took part in the conference. A total of 36 young scientists exchanged their latest research results with top scientists. Photo: Yang Tian Peng INTERNATIONAL CONFERENCE ON LASER INTERACTION WITH MATERIAL AND APPLIED LASER 2019 (LIMA) / The latest innovations and trends from research and development as well as technological challenges were presented and discussed at the "International Conference on Laser Interaction with Material and Applied Laser 2019 (LIMA)" in Shanghai. Dr. K. Zimmer, head of the working group "Micro- and Nanostructuring with Lasers" at IOM and cooperation partner of the "Joint International Research Laboratory of Laser-based Manufacturing and Materials" in Shanghai was significantly involved in the organization and design of the conference. The creation of a sustainable cooperation network to promote the exchange of information, the cooperative research of new effects and the implementation of concrete scientific projects was the aim of the conference. “”“”z“meitn”z

COMPATIBILITY OF CAREER AND PERSONAL LIFE / Employees who can successfully balance work and personal life are the most valuable asset for the success of IOM. Flexible working time, a parents child room, the organization of meetings and scientific colloquia within core working hours as well as individualized support in challenging family situations are important measures. Based on these principles, the needs for improvement are regularly assessed and implemented within the certification process “auditberufundfamilie” (“audit work and family”). For example, support of families during working times in other countries has been compiled.

REPORTS THIN FILMS WITH NANO- AND ATOMIC STRUCTURES Laser Irradiation-induced Modification and Crystallisation Dynamics of Epitaxial Phase Change Thin Films Grown by Pulsed Laser Deposition A. Lotnyk, M. Behrens, J.W. Gerlach, M. Ehrhardt, P. Lorenz, B. Rauschenbach Introduction The working principle of conventional phase change memory is based on ultrafast reversible phase changes between crystalline and amorphous phases of Ge-Sb-Te (GST) materials. For information stor- age, a phase change memory device uses a large contrast either in electrical resistance between the amorphous phase (high-resistance state) and crys- talline phase (low-resistances state) or in optical re- flectivity between the amorphous phase (low reflec- tivity state) and crystalline phase (high reflectivity phase). Erasing of a GST-based memory cell is achieved by applying a high intensity pulse, either electrical or by a laser beam. These processes lead to the amorphization via melting and subsequent fast quenching of the phase change alloy. However, GST alloys are poor glass formers. Thus, high cooling rates are required to suppress the recrystallization of the alloys during the erase process. On the other hand, the write process is accomplished by applying either electrical or optical pulses with low intensity, resulting in an amorphous-to-crystalline phase tran- sition. Due to intrinsic features of GST alloys, a main challenge in material science is the optimisation of memory writing times, which are limited by the crys- tallization kinetics of GST alloys. In order to increase the crystallisation rates, several strategies were pro- posed, including doping of GST materials, pre-crys- tallization of an amorphous matrix or using GST- based superlattices [1]. Being a nucleation-dominant material, improvements in crystallization speed can be, however, achieved by taking advantage of inter- face assisted crystal growth along a preferred crys- tallographic direction using epitaxial thin film systems [2]. This approach will allow to overcome the time-lag originating from the incubation period during nuclea- tion. This work aims to study structural modifications and crystallisation dynamics of epitaxial Ge2Sb2Te5 (GST225) phase change thin films induced by nano- second single pulse laser irradiation [3-5]. In particu- lar, the epitaxial recrystallization of cubic GST225 (c- GST225) from a transient molten phase during the cool-down process is monitored by time-resolved op- tical reflectivity measurements and subsequently evaluated by high-resolution scanning transmission electron microscopy (HRSTEM) in detail. The ap- proach to use such epitaxial thin films allowed to de- 18 velop a method for quantification of ultrafast crystal- lisation dynamics. The crystallisation process was identified to be purely driven by crystal growth. Thus, direct access to the crystal growth kinetics in an ap- plication relevant scenario is shown, excluding any interferences with concomitant nucleation or influ- ence of varying populations of subcritical nuclei in the amorphous phase [5]. Overall, the introduced meth- odology can be applied to a broad spectrum of simi- lar materials and glasses in order to study solidifica- tion characteristics involving crystallization and amorphization on application relevant length and time scales. Experiment Epitaxial t-GST225 thin films were deposited on Si(111) substrates by pulsed laser deposition (PLD) [3,4]. The structure of the as-grown thin films was confirmed by X-ray diffraction measurements. The microstructure of GST225 thin films was studied in a probe Cs-corrected Titan3 G2 60–300 micro- scope operating at 300 kV accelerating voltage. High-resolution TEM (HRTEM) micrographs were acquired using a Gatan CCD camera. For HRSTEM, a probe forming annular aperture of 25 mrad was ap- plied and all images were recorded with a HAADF detector using annular ranges of 80-200 mrad. The preparation of specimens for TEM observations were done by a combination of focused high- and low-en- ergy ion beam milling. To monitor the changes in reflectivity upon laser irra- diation, a pump-probe setup was designed with an excimer laser of 248 nm wavelength and 20 ns pulse duration as pump source, whereas a diode laser of 633 nm operating in CW mode was used as probe source. The spot size of the pump laser beam on the surface of the thin films was 0.03 cm². The probe la- ser beam was detected by a Si photodiode and pro- cessed with a digital oscilloscope. The overall time resolution of the setup was 2 ns. Results and Discussion The insights into the structural modification of t- GST225 thin films upon ns-laser irradiation was de- duced from studies at the nanoscale by using TEM [2]. Figure 1 shows a TEM image of a GST225 thin THIN FILMSWITH NANO- AND ATOMIC STRUCTURES REPORTS film after singlens-pulse laser irradiation at a fluence of 35 mJ/cm2. The film can be divided intothree dis-tinct regions(I, II and III) [2]. According to the image contrast and corresponding nanobeamelectron dif-fraction(NBD)patterns, the region I reveals an amor-phous GSTphase, whereas regions II and III repre-sent a crystallinestructure. The NBDtaken from re-gion III revealed the as-grownt-GST255phase, where the phase did not significantlychange upon the laser irradiation. In contrast, the crystal phase in region II is c-GST225.Thus, the resultsof Figure 1 verify the phase transition from the layeredt-GST225phase to the cubicGST225phase.The cubicphase forms froma transient molten phase at the melt-crys-talline interface upon the coolingprocess and crys-tallizeswithan epitaxial relationshipto the parent phase. These findings are particularly useful for de-terminationof crystallization dynamics of epitaxial GST225 thinfilms. The combinationof TEM(identifi-cationof thickness ofthe cubicphase, d in m) and pump-probe experiments(identification of time needed for the crystallization of cubic phase, t in s) will allow the identificationof the crystallization rates (v=d/t) of the c-GST225 phase. Figure 2 showsthe results of pump-probe experi-ments. The Figure represents the temporal evolutionof the reflectivity of epitaxial t-GST225 thin films upon irradiation with a single ns-laser pulse of fluences inthe rangebetween 12 and 50 mJ/cm². In general,the reflectivity first decreases after exposingthe thin films to the ns-laser pulse. Thiscan be attributed to an initiated melting process of GST225 that fully un-foldsat the endof the laser pulse where the maxi-mumtemperature isreached [5]. Additionally, high UV light absorption of GST225 resultsin a strong temperature inhomogeneity along the cross-sectionof the thin film. Asa consequence, different cooling ratesalong the cross-sectionof the thinfilm are in-volved in the subsequent cool-down process of the materialcausing it to either recrystallize into the cu-bicphase of GST225 or quench into the amorphousphase (critical cooling rate ~109- 1012K/s). Accord-ingly, these solidification characteristics become dis-cernible in the further temporal evolutionof the re-flectivity showing a clearincrease in reflectivity. The latter can be ascribed to the recrystallizationof c-GST225 fromthe liquid phase duringthe cool-downprocess. However, since c-GST225 exhibitsa lower reflectivity than t-GST[3], the initial reflectivity isnotfully restored. Moreover,a melt-quenched amor-phous layer, which could also formduringthe cool-downprocess, might additionally contribute to a re-ducedreflectivity.Consequently,the final reflectivity isdetermined by the layer thickness distribution within the evolving three-layer stack consistingof a remaining t-GST225, a recrystallized c-GST225 anda melt-quenched a-GST225 layer (see Figure 1). Asa result,by tuning the laser fluence and hence the layer thickness distribution in the GST225 thin film, multiple reflectivity statescan be obtained. Thispaves the way for ultrafast multilevel data storage based on definite repositioning of planarinterfaces between distinct layersof single phase GST225, promisingenhanced precisionand scalability com-pared to the traditional paradigm of controllingran-domly distributed amorphousand polycrystallinefractions of phase-change material. Furthermore, thedata encodingprocess istriggered by only a singlens-laser pulse in each case, whereas most methods rely on the accumulation of multiplepulses in orderFigure 1:TEM imageofa laserirradiatedGST225 thin film showingthreeregions ofdifferent crystal structure together with corresponding nanobeam electron diffraction patterns. Figure 2: Timedependency ofthereflectivity ofanepitaxial t-GST thin film duringirradiation witha single, 20nslaserpulse atfluencesvarying between 12and 50mJ/cm². The ns-laser pulse isapplied att = 0 ns. 19

REPORTS THIN FILMS WITH NANO- AND ATOMIC STRUCTURES to obtain intermediate reflectivity or resistivity levels, which is at the expense of time. Figure 3(a) shows geometrical phase analysis (GPA) processed TEM images of the GST225 thin films af- ter laser irradiation for two selected fluences of 31 mJ/cm2 to 44 mJ/cm². The thickness of the recrystal- lized c-GST225 layer increases with the increasing fluence, while the thickness of the remaining t- GST225 layer decreases [5]. Remarkably, in the case of a single laser pulse of 44 mJ/cm² applied, a complete transition to the c-GST225 phase occurs, demonstrating an optimized match between the laser fluence and the thin film thickness, whereas for higher fluences amorphization in the upper part of the thin film occurs [5]. Importantly, the measure- ments reveal an epitaxial relationship between the t- GST225 and c-GST225 layer, which confirms that the recrystallization of the cubic structure is a crystal growth dominated process. The crystallisation starts at the crystalline-melt interface and proceeds in an epitaxial fashion towards the top of the thin film. Nev- ertheless, as indicated by ab initio molecular dynam- ics simulations, a supportive element during this re- crystallization process could be remaining structural fragments of crystalline GST225 close to the t- GST225 boundary due to incomplete melting, which enables recrystallization with small atomic move- ments. Interestingly, in the case of 44 mJ/cm², no t- GST225 structure remained at all which shifts the fo- cus to the Si(111) substrate. In this case, the sub- strate acts as a recrystallization template. However, a corresponding RGB rotation image calculated from GPA (Figure 3), reveals similar tendencies like in Fig- ure 1: an adoption of the orientation of typical t- GST225(111) twins by the recrystallized c-GST225 structure. This might be a sign, that besides the un- derlying Si(111) substrate also the initial t-GST225 structure dictates the formation of c-GST225 phase. This assumption finds further support by the mostly intact interface between the substrate and the GST225 thin film. A possible scenario could be, that Figure 3: GPA rotation images of t-GST225 thin films irradiated with single ns-laser pulse at fluences of (a) 31 mJ/cm² and (b) 44 mJ/cm². Insets show FFT and HRSTEM images. 20 at temperatures approaching the melting point the Te sublattice is only weakly fragmented, whereas the mobility of Ge/Sb atoms is strongly increased, lead- ing to an enhanced recrystallization into the cubic structure upon subsequent fast cooling compared to starting from a liquid phase. By relating the travelled path of the recrystallization front of c-GST225 to the recovery time of the reflec- tivity extracted from Figure 2, the mean crystal growth velocity of c-GST along the (111) direction can be obtained (Figure 4). However, during the re- flectivity measurements a small part of scattered light from the intense UV pump pulse is additionally de- tected by the photodiode. For higher fluences, this overlap with the probe signal becomes noticeable by a weaker decrease in reflectivity starting at about t = 17 ns due to the impact of the falling edge of the pump pulse. However, the ending point of the recrys- tallization process is not obscured and can be clearly identified in Figure 2, except for irradiation with 50 mJ/cm², where the 20 nm thick amorphous top layer prevents the detection of the crystallization front by the probe laser due to limited penetration depth of the laser light [5]. The starting point of recrystalliza- tion is expected to be at the end of the laser pulse at t = 20 ns where the material immediately starts to cool down and the solid-melt interface being at 900 K starts to move towards the top of the thin film. How- ever, in Figure 2, the minimum in reflectivity for the irradiation fluence of 22 mJ/cm² is at about 24 ns, in- dicating a delay time of approximately 4 ns for crys- tallization. This delay time is repeatedly observed during measurements on epitaxial t-GST225 thin films and could be attributed to an instability of form- ing crystalline nuclei at temperatures still close to the melting point. Obviously, the crystal growth velocity increases with increasing fluence from ~0.4 m/s for 18 mJ/cm² up to ~1.7 m/s for 44 mJ/cm², whereas at higher fluences saturation is observed. This satura- tion can be expected, considering that for higher flu- ences an increased part of the thin film is trans- formed without initiating an amorphization during the cool-down process. In contrast, by further increasing the fluence up to 50 mJ/cm², amorphization due to a comparatively higher cooling rate is found. Accord- ingly, in the case of 44 mJ/cm², the solidification of GST225 takes place at the highest possible cooling rate. Hence, the highest detectable crystal growth velocity of the employed epitaxial GST225 thin film model system is 1.7 m/s, which is well in line with a recently theoretically predicted value (~1.5 m/s at ~ 700 K). Nevertheless, considering that the obtained crystal growth velocities in the present work repre- sent a mean value covering the entire cross-section of the thin film, peak velocities exceeding 2 m/s are THIN FILMSWITH NANO- AND ATOMIC STRUCTURES REPORTS assumed. Thus, the obtained valuesalso seemplau-sible with regard to the growth velocitiesobtained by ultrafast DSC(~2.8m/s). In contrast, experimentalstudies capturing crystallization ratesof melt-quenched GSTin application relevant scenarios mostly report lower maximumgrowth rates in the rangeof 1 m/s, whilesimilar values are also reported in earlier theoretical works. In thiswork, a substantial difference compared to the above-mentioned exper-imentalstudiesisthe use ofepitaxial GST225, which allowsthe directed recrystallization of the c-GST225 structure along its[111] direction, where a planarboundary of either [0001] oriented t-GST225 or [111]oriented Siservesas a recrystallization template. Hence, the slightly increased crystal growth speedfoundinthiswork could be dueto the improvedcrys-talline quality and the reduced crystal growth activa-tionenergy resulting fromthe epitaxial recrystalliza-tionmechanism. It should be also mentioned, thatbesides different thermal responses of the GST225 thinfilm to ns-laser heating, theimpact ofsize effects on the viscosity couldbecome crucialduring the so-lidification process, which could lead to reduced crys-talgrowth kinetics incase of only smallvolumes of GST225 being transformed.Conclusion In conclusion, structural modifications and crystal growth dynamics ofepitaxial t-GST225 thin films in-duced by single ns-laser pulse irradiation are stud-ied. By combining laser-assisted time resolvedre-flectivity measurementswith HRSTEM, the ns-laser induced structural transitions are temporally and spa-tially resolved. It isfound, that dueto laser heating, the thin films partially melt,followed by epitaxialre-crystallizationinto the cubicphase of GST225 duringthe subsequent cooldownprocess. Thisresultsinthe formationof multiplereflectivity states based on the relocation of planarinterfaces between single-phase layers of GST225, offering a novel approach to multileveldata storage in phase change memory. By extracting the durations for the growth of the re-crystallizedc-GST225 layers andthe corresponding thicknesses, the obtained crystal growth rates are ranging from 0.4 m/s to 1.7m/s. The latter representsthe upperlimit of the employed epitaxial GST225 thinfilm modelsystem, when amorphization isto be avoided.In essence, the present work shedslight intothe crystal growth kinetics of GST225 andbe-yond that, introduces a methodfor quantification of crystallizationspeeds and amorphizationprocesses of a broad variety of similar phase-changesystems.Moreover, thisworkdemonstratesamorphizationandcrystallization of GST225 material by using UV laser with single pulse durationandwavelength only,where in the conventionalamorphous-to-crystallinephase transitions lasers with different pulse dura-tions, number and wavelengths are usually applied. Acknowledgements The financial support of the Free State of Saxony within the project “Switching with light” (SABproject) isgreatly acknowledged.The authors thankMrs. A.Mill for TEM specimen preparation. Literature[1]A. Lotnyk,I.Hilmi,U.Ross,B. Rauschenbach,NanoRese-arch 11(2018)1676[2]M.Behrens, A. Lotnyk,J.W. Gerlach,I. Hilmi, T.Abel, P.Lorenz, B. Rauschenbach, Nanoscale 10(2018)22946[3]M.Behrens, A. Lotnyk,U.Roß, J. Griebel,P. Schumacher,J.W. Gerlach,B.Rauschenbach, CrystEngComm 20(2018)3688[4]A. Lotnyk,M.Behrens, B. Rauschenbach, NanoscaleAdv.1 (2019)3836[5]M.Behrens, A. Lotnyk,J.W. Gerlach,M.Ehrhardt,P.Lorenz, B. Rauschenbach, ACSAppl.Mater. Interfaces11(2019)41544Figure 4: Crystal growth velocitiesin dependency ofappliedlaserfluencesaswellasexponential fitto thedata with A = 30m/s and B = -0.17cm²/mJ.. 1

REPORTS THIN FILMS WITH NANO- AND ATOMIC STRUCTURES High-Energy Electron-Treatment of Biological Hydrogels: Biomimetic Hydrogels, Stimuli-Responsive Systems and Functional Surfaces S. Riedel, P. Hietschold, R. Konieczny, W. Knolle, S. G. Mayr Introduction Biological hydrogels such as collagen and gelatin are highly attractive materials for tissue engineering and biomedicine. Due to their excellent biocompatibility and biodegradability, they represent promising can- didates in regenerative medicine, cell culture, tissue replacement and wound dressing applications. They are characterized as polymeric networks with the ability to absorb, store and release large amounts of water while maintaining their dimensional stability. Due to this swelling behaviour, hydrogels represent promising materials in biomedical applications where hydration-responsive materials are required. They can be classified into natural and synthetic hydro- gels, distinguished by their source. Natural hydrogels are obtained from biological sources while synthetic hydrogels are artificially pro- duced. While synthetization of hydrogels enables precise control of composition, structure and material properties, natural hydrogels show strong conformity to biological tissue. This conformity is needed in tis- sue engineering and replacement, as biomedical coatings, culture substrate for cells and tissues or as implants. As the main structural protein in the extra- cellular matrix, collagen is a highly attractive candi- date for biomedical applications due to its biocom- patibility and low immunogenicity. As a derivative of collagen, gelatin shows a similar degree of biocom- patibility and biodegradability, which makes it ex- tremely interesting as biomaterial. However, in case of gelatin, thermal stability has to be enhanced for many biomedical applications because gelatin un- dergoes a gel-sol transition at temperatures under- neath the human body temperature. Thermal stabili- zation can be obtained by polymer crosslinking, which further tunes material properties such as net- work organization, rheological properties, swelling and stimuli-responsiveness. Electron-beam-induced crosslinking is a reagent- free and efficient technique to crosslink hydrogels [1]. Other methods utilize chemical crosslinkers, dehy- drothermal treatment or ionizing radiation. While the use of chemical crosslinkers always introduces addi- tional components into the system and dehydrother- mal processing is not applicable to hydrogels in wet state and at room temperature, ionizing radiation promises non-toxic and reagent-free crosslinking un- 22 der ambient conditions. Compared to radiation tech- niques utilizing gamma- and UV-irradiation, electron- beam treatment provides higher irradiation rates and higher penetration depths, respectively. With this, electron-beam-treatment represents a highly favourable and promising technique to cross- link hydrogels for biomedical applications. However, the high potential of electron-beam treated collagen gels and their cytocompatibility is not yet sufficiently investigated. In addition, electron irradiated gelatin shows fascinating features, which can be used to de- velop stimuli-responsive systems and functional sur- faces. These aspects were investigated in more de- tail in the report period. Experiment Collagen gels were prepared from rat-tail collagen (collagen R, 0.4 % solution, Cat. No. 47256.01; SERVA Electrophoresis, Germany) and bovine skin collagen (collagen G, 0.4 % solution, Cat. No. L 7213; Biochrom, Germany) in a ratio of 1:2, respec- tively. The collagen solution was prepared on ice to avoid polymerization and was gently mixed until ho- mogeneity. A phosphate buffer containing Na2HPO4 (Cat. No. 71636; Sigma-Aldrich Chemie GmbH, Ger- many) and NaH2PO4 (Cat. No. 71507; Sigma-Aldrich Chemie GmbH) was added to obtain a pH of 7.5 and a total phosphate molarity of 200 mM in all gels. The collagen samples polymerized at 37 °C and 100 % humidity for 24 h. The samples were rinsed twice and stored in distilled water at room temperature until use. The gelatin samples are prepared by dispersing gel- atin type A from porcine skin (G2500, Sigma-Aldrich Chemie GmbH, Germany) in deionized water with various concentrations up to 10 wt%. After a swelling time of 1 h, the gelatin solution is heated to 60 °C un- til the gelatin is liquefied and homogenously dis- persed. The gelatin solution is poured into moulds or petri dishes to obtain the shapes desired for the ex- periments. Afterward, they are cooled to 8 °C for at least 2 h to polymerize. Between measurements, the samples are stored at 8 °C. Irradiation was performed using a 10 MeV linear electron accelerator (MB10-30MP; Mevex Corp., THIN FILMSWITH NANO- AND ATOMIC STRUCTURES REPORTS Canada). The electron accelerator isequipped witha moving stage with a repetition rate of 180Hz and a scanning horn with scanning frequency of 3 Hz.The electron pulses have a length of 8 µs. Final doses ranging from 5 to 100 kGy were obtained instepsof 5 kGy. The doses were measured with re-spect to a graphite dosimeterto an uncertainty of 5 %. During electron beamtreatment, the sampleswere cooled to room temperature by draft to prevent overheating and thereby induced degradation. After irradiation, the sampleswere stored at 37 °C and 100 % humidity for 48 h and later at RT or 8 °C. The obtained materials and systems were then ana-lysed via various different techniquesdependingon the intended application. The biomimeticcollagen hydrogelswereinvestigated via FTIR spectroscopy, 3D microscopy, network analysis, rheological meas-urementsand cytocompatibility tests [1]. The devel-opedstimuli-responsive gelatin systems were char-acterizedexperimentally via determination of re-sponse efficiency [2]. In addition, the system wassimulated by molecular dynamics. The functional surfaces were analysed via atomicforce microscopy at physiological conditions, 3D microscopy and cyto-compatibility as well as long-time degradation tests [3,4]. Results and DiscussionBiomimetic Collagen Gels The performed experimentswere able to demon-strate that electron beamtreatment enablesprecise modificationof collagen hydrogels towards controlla-bleECM modelsystems [1]. FTIR measurementsin-dicate that electron beamassisted crosslinkingin-duces only minor changes, while the characteristicpolymeric structure ofcollagen ismaintained also for doses as high as 100kGy.Pore sizeanalysisindi-catesprecise tunability of the network pore size. Rheological investigations (see Fig. 1) show network stiffening over one order of magnitude, which corre-lates with an increase in crosslinkingdensity.Thereby, our cell-experiments(see Fig. 2) revealed an excellent cytocompatibility of electron irradiated collagen gelsin terms of cellular viability. With these investigations, high-energy electron irradiationin-duced crosslinkingisshown to be a highly promisingtechniqueto tune collagen hydrogelsinorder to mimic the extracellular matrix and other collagenoustissuesby tailoring material characteristics such as structure and mechanics ina physiological relevantrange. In addition to excellent cytocompatibility,these defined collagen systems represent 3D tissue models which are highly relevant incell culture, as coatings or implants and are necessary to study cel lular behaviour in biomimetic tissue as in cancer re-search or to investigate drug delivery and distributionfor pharmaceutical applications. Stimuli-Responsive Gelatin Systems It wasalso possible to realizethe development of a thermal responsivegelatinsystem by high-energy electron irradiation for actuatoric applications [2].Thisisachieved by introductionof a shape-memory effect (see Figure 3), viz.,a temperature-induced transition froma secondary intoa primary shapethathasbeen programmed in the first place merely by exposure to energeticelectronswithout addition of Figure 1:Storage and loss moduli ofelectron irradiatedcolla-gen (2mg/ml) in dependence onradiation dose,with powerlaw fits.Errorbarsindicate standarddeviation.Figure 2:Cellularviability: NIH 3T3 fibroblastsculturedonelectron crosslinkedcollagengels (2mg/ml) asfunction ofir-radiation dose.Errorbarsindicate standarddeviation.3

REPORTS THIN FILMS WITH NANO- AND ATOMIC STRUCTURES Figure 3: Sketch of the experimental steps of programming and demonstrating the shape-memory effect in electron-beam mod- ified gelatin. Exemplarily, deformation of a bent gelatin layer is shown. (a) Gelatin is irradiated with 10 MeV electrons. (b) Irra- diated gelatin is heated to 50 °C. (c) The sample is deformed into a temporary shape and then cooled to 8 °C. (d) The de- formed sample is heated again to 50 °C to initiate shape- memory effect resulting in (e) almost complete shape recovery. potentially hazardous crosslinkers. While this sce- nario is experimentally quantified for exemplary ac- tuators, a theoretical framework capable of unravel- ling the molecular foundations and predicting exper- iments is also presented. It particularly employs mo- lecular dynamics modelling based on force fields that are also derived within this work. Implementing this functionality into a highly accepted material, these findings open an avenue for large-scale application in a broad range of areas. Functional Gelatin Surfaces It was further possible to develop mechanically pat- terned gelatin surfaces (see Figure 4) by a two-step- process involving local as well as global electron ir- radiation for patterning and thermal stabilization, re- spectively. Our investigations indicate that focused electron irradiation as used in electron-beam lithog- raphy is an effective and precise reagent-free tech- nique to mechanically pattern hydrogels such as gel- atin in order to obtain functional biomaterials and - surfaces. We were able to show that gelatin layers have a precise topographical and mechanical pattern with excellent periodicity after local irradiation in the dry state and following rehydration. Irradiation using highly focused electron beams further enables crea- tion of various different patterns in the µm-range and even lower. Global electron irradiation in wet condi- tions induces thermal Figure : AFM images of mechanically patterned gelatin layers. Top: Dry state before global irradiation. Bottom: Wet state after global irradiation. (a) Topographical image showing height in- formation of the layer. (b) Mechanical image showing local E- modulus. stability of the functionalized layers for possible bio- medical applications. By varying the hydrogel, irradi- ation conditions, as well as gel concentration, cus- tomization of the reagent free mechanically pat- terned polymer substrate is possible. Next to mechanically patterned gelatin surfaces, topographically patterned gelatin hydrogels are of high interest for example to develop customized cul- ture substrates for tissue regeneration. Therefore, we described a patterning method utilizing moulding wherein a silicon template was used to transfer cus- tomized stripe patterns onto gelatin hydrogels. The patterned hydrogels were then stabilized against gel−sol transition by high-energy electron beam treatment, inducing network crosslinking. Pattern transfer was then investigated in dependence on gel- atin concentration and irradiation dose. In addition, cytocompatibility experiments of HUVECs and NHDFs on the patterned hydrogels were performed. The study showed gelatin concentration dependen- cies of the pattern transfer. It was able to determine a pattern transfer optimum at gel concentrations around 12−14 wt %. In addition, the effect of irradia- tion dose on pattern transfer was investigated, show- ing strong dependencies on dose, which enables precise adaption of the pattern. Long-time experi- ments (see Figure 5) at physiological conditions demonstrated stability of the pattern up to 40 days, which enables long-time applications. The cytocom- patibility tests demonstrated good biocompatibility and low toxicity to HUVECs and even better biocom- patibility and extremely low toxicity to NHDFs in pres- 24 THIN FILMSWITH NANO- AND ATOMIC STRUCTURES REPORTS ence of patterned gelatinehydrogels. Significantdif-ferences between cellsgrown onplain gelatin hydro-gels compared to cellsgrown onpatterned hydrogelswere found. Thisindicates excellent contact guid-ance potential and improved cellular growth supportof patterned hydrogel substrates, pointing outtheirpotential usage for regenerative medicine applica-tions. Future geneticanalysisof cellsculturedon cross-linked patterned and unpatterned gelatin in comparison with in vivo grown fibroblasts willunravel the differences of the 3D model and the in vivo con-dition. Conclusion In conclusion, we were able to demonstrate the highpotential of high-energy electron crosslinked hydro-gels for biomedical applications. We introduced new conceptsfor the developmentof biomimeticas well as stimuli-responsive materials andfunctional sur-faces fromcollagen and gelatin.High-energy elec-tron-crosslinkingwas shown to be a highly advanta-geous technique to tune various materialpropertiessuch asmechanical and structural propertiesor stim-uli-response while excellently maintaining cytocom-patibility and chemical integrity. These investigationsand conceptsmight be the basisfor optimizedsyn-thetization of highly functional,customizable and smart biocompatible hydrogelmaterialsfor specificapplications such as inregenerative medicine, im-plant development or tissue engineering. Literature[1]S. Riedel*,P. Hietschold*,C.Krömmelbein, T.Kunsch-mann,R.Konieczny,W. Knolle,C.Mierke,M.Zink, S.G.Mayr, Materials & Design 168 (2019)107606; *contributedequally[2]S. Riedel, S. G.Mayr, Physical ReviewApplied9 (2018)024011[3]S. Riedel,K. Bela,E. I.Wisotzki,C.Suckfüll, J. Zajadacz,S. G. Mayr, Materials & Design 153 (2018)80[4]M.Tadsen*,R.P.Friedrich*,S. Riedel*,C.Alexiou, S.G.Mayr, AppliedMaterials & Interfaces11(2019)7450; *con-tributedequally55

REPORTS ULTRA-PRECISION FIGURING AND PATTERNING OF SURFACES Ion Beam Planarization of Optical Aluminium Surfaces M. Ulitschka, J. Bauer, T. Arnold Introduction For many years aluminium has been used as con- struction material for optical mirrors, e.g. in laser sys- tems, spectrometers, or telescopes, as it is cheap, lightweight, and can be easily machined employing ultra-precision single point diamond turning or milling technologies. Furthermore, aluminium has a high re- flection coefficient which ranges from the infrared to the shortwave visible (VIS) and ultraviolet (UV) spec- tral range with values well above 90%. The surface error topography after manufacturing by single-point diamond turning (SPDT) is applicable in the infrared spectral range. The optical surface has roughness values of typically below 10 nm root mean square (RMS) and at best 2 – 3 nm. The machined surface after SPDT exhibits a periodic groove pattern micro- structures left by the cutting tool. Those so-called turning marks have a pitch of some microns and an amplitude ranging between 10 – 30 nm. Therefore, these periodic patterns have similar effects as a dif- fraction grating in optical applications in visible and ultraviolet spectral range. Thus, for increasing de- mands on the optical surface quality in the shortwave VIS and UV spectral range further improvement of the surface form and roughness is required. Stand- ard optical surfacing techniques comprise a pro- cessing chain where preshaped aluminium surfaces are coated by amorphous NiP for further diamond turning, followed by mechanical polishing or ion beam planarization (IPB) and form error correction steps employing e.g. magnetorheological finishing (MRF) or ion beam finishing (IBF). NiP has an iso- tropic amorphous matrix which is suitable for the combination of SPDT and polishing processes, as well as ion beam techniques. Diamond-turned NiP reveals even smoother surfaces than pure aluminium and can be further improved by one or multiple se- quential ion beam planarization processes where turning marks are successfully reduced. Hence, mi- cro roughness values of <1 nm RMS are achievable, resulting in sufficiently smooth optical surfaces. Fi- nally, an additional metallization layer on top of the NiP coating is necessary to realize the desired reflec- tive properties for the specific application. However, the mismatch of thermal expansion coefficients be- tween aluminium and NiP coating can cause me- chanical stress formation under thermal load condi- tions resulting in bending and distortion of the optical surface. Hence, it is desirable to perform form cor- rection and smoothing of the optical surface on the 26 pure aluminium surface with no further coating by means of ion beam techniques directly after the premachining by SPDT. However, the microstructure of aluminium leads to severe roughening when bom- barded with inert gas ions such as argon. In contrast, it has been shown that reactive ion beam etching (RIBE) using reactive process gases such as oxygen and nitrogen allows the original surface topography to be maintained during ion beam processing. Thus, this technology allows figure error correction of alu- minium mirrors without degradation of the surface quality, as it was shown in [1]. The IBP process rep- resents another promising technology also for the treatment of pure aluminium surfaces. In IBP the rough substrate surface is covered with a planarizing layer of a specific thickness, so that the high-spatial frequency surface roughness features are fully em- bedded and surface waviness is levelled to a consid- erable extend. As a result, a smooth and planar sur- face is revealed. Depending on the initial surface quality, the thickness of the planarizing film typically ranges between some 100 nm and a few microns. Then, the plane surface is transferred to the underly- ing substrate by ion beam etching. To ensure an op- timum surface transfer, the etch rates of planarizing film and aluminium substrate should be equal. In most cases the planarizing layer consists of a pho- toresist applied by spin coating to the surface. In the present work the preparation of the photoresist layer was investigated aiming at maximum stability and roughness preservation during ion beam etching us- ing nitrogen as process gas. The optimum prepara- tion steps were explored based on roughness evalu- ation, analysis of chemical modifications, and etch resistance of the photoresist during ion beam irradi- ation. Furthermore, a process route for smoothing of aluminium surfaces was evaluated to attain the re- quired surface quality. Reactive ion beam etching- based planarization was conducted on single-point diamond turned aluminium alloys (RSA Al905 and RSA Al6061). Such alloys are standard materials in optical mirror fabrication. The optimum process route and the roughness evaluation was explored by topo- graphic analysis applying a combination of white light interferometry and atomic force microscopy meas- urements. It has turned out that a 2-step process (comprising the nitrogen ion beam planarization step followed by an ion beam irradiation using oxygen as process gas) results in a significant improvement of ULTRA-PRECISION FIGURING AND PATTERNING OF SURFACES REPORTS aluminium surface roughness over a broad spatial frequency range.Experiment For the experimentsdiamond turned aluminium disc samplesof 50 mm in diameterwereused as test substrates. The negative workingphotoresist ma-N 2405 (micro resist technology)was employedas the planarization layer.The substrateswere cleaned with acetone prior to photoresist spincoatingper-formed at 30 secondsat 3000 rotations perminute. The substrateswere prebaked at 90°C to evaporate the solvents. In accordance to the thickness of the substrate materials, the bakingtimes for silicon wafer and aluminium substrate were adapted. Conven-tional DUV exposure in a photolithography system was then applied toprovide a homogeneousand well crosslinked polymer matrix. An optional postbakingstep was applied at 150°C on a hotplate for 2 minutes on silicon wafer and 10 minutes on aluminium. After allapplication steps the photoresist layer thickness was approximately 500 nm. Ion beam machining experiments were performed in a high vacuumchamberwith a base pressure of 2x10-5Pa. The ionbeamwas generated by a 13.56 MHz radio frequency (RF) ion source with a focusing triple grid extractionsystem allowinga constriction ofthe free-beamwithout use of an aperture. The water-cooled sample holderwas mounted on a five-axismotionsystem. The watercooling ensures efficient heatdissipation from the sample reducing thermal ef-fects duringthe process. The ion beam parameters were chosen to resultin a Gaussian shaped ion cur-rent density distributionfunction exhibiting a full-width at halfmaximum(FWHM) of 4-15 mm. Nitro-gen and oxygen process gas was used for the gen-eration of low-energy ion beams at ≤1.5 kV beam voltage. The machining experimentswere performed at normal ion beamincidence angle with respect to the substrate surface. In order to investigatethe effects in resist etching, preliminary experimentswere performed on spin coatedsilicon wafers with a diameterof 2 inch. An aluminium mask with an opening diameter of 13 mm defined the machining area for ion beam test etching experimentsto determinethe etch rates of planariza-tionlayer and aluminium. The ion beam wasscanned applying a raster path overthe surface with a con-stant velocity of 4 mm/sand a linepitch of 1 mm in order to ensure a homogeneous material removal. Ion beamplanarization experimentson RSA Al6061 and RSA Al905wereperformed in a two-step pro-cess. In the first planarization process step the entire aluminium mirror surface, coated with the photoresist layer, withoutan additional mask wasetched with N2. During thisprocess step 8– 10 scan repetitions werenecessary to remove the whole photoresist layer.In a subsequent second process step the aluminium surface was etched directly with O2within 1 scan rep-etition. For the second RIBE finishing step no photo-resist layer was used.The sample topography was analyzed by whitelight interferometry (WLI; Bruker NPFLEXTM 3D Surface Metrology System) and atomicforce microscopy (AFM; Bruker DimensionICON). For WLI an objec-tive with 5fold magnification was used with a 1x fieldof view multiplier in phase-shift interferometry mode. The image size was 1230µmx 925µm with a pixel resolutionof 640 x 480. AFM wasoperated in tapping mode in a xy -closed loop configuration. Scanningar-easof 10 µm x 10 µmand 50 µm x 50 µmwere measured with a pixel resolution of1024x 1024. The raw data were subjected to a planecorrection con-sistingof a global plane fit and aline-wise correctionsubtracting a fitted polynomialfunctionof the 3rd or-der fromeach scan line via SPIPTMsoftware. Surface roughness analysiswasperformed via calculatingthe power spectral density (PSD) function usinga self-written MATLAB® script.By calculatingthe square root ofthe integrated PSD, root mean square(RMS)roughness valueswere evaluated.The spatial frequency ranges for waviness/roughness and mi-croroughness were defined as0.0024 µm-1–1.7 µm-1and 1.7 µm-1–20 µm-1, respectively. Consequently,the full rangeRMS roughness was calculated inthe spatial frequency range of 0.0024 µm-1– 20 µm-1.Results and DiscussionThe initialaim of the work was to determine the opti-mumpostbakingtemperature ofthe photoresist in or-derto obtain maximumlong termstability of the resist layer. GC-MS measurementsindicate that remaining amountsof organicsolvent are almost completely re-movedduring postbakingat 150°C. AFM measure-mentsreveal that the initial surface roughness of ap-proximately 0.35 nm RMS is preserved. Postbakingat elevated temperatures above 200°C showsthermo-oxidative degradations. Thisresult isof high importance since the degradationmechanism can also be expected to appear during ionbeam treat-ments, if the heatdissipation is notsufficient. Indeed,a strong resist degradation was observedat either high ion current densities, which are accompanied by a strong thermal impact into the resist layer, or for insufficient sample cooling. In a next step, the capability of the photoresist to em-bed the roughness features of a SPDTaluminiumsurface was investigated. 7

REPORTS ULTRA-PRECISION FIGURING AND PATTERNING OF SURFACES d) ] 4 m n [ D S P c p o r t i o s i n a e m 108 106 104 102 100 a) b) 30 nm 20 nm 0 nm 0 nm 10 µm 1 µm 15 nm 4 nm 0 nm c) 15 nm 0 nm d) ] 4 m n [ D S P c p o r t o s i i n a e m 108 106 104 102 100 10 µm 0 nm 1 µm 4 nm 0 nm 10 µm 1 µm aluminium surface coated with ma-N 2405 (before postbake) coated with ma-N 2405 (after postbake) AFM ( 35 µm x 35 µm) AFM ( 3 µm x 3 µm) 10-1 100 101 spatial frequency [µm-1] Figure 1: AFM measurements a) bare Al905 surface, b) spin- coated, prebaked and DUV exposed, c) after postbaking and d) PSD function. From Fig. 1 it can be seen that the initial surface of Al905 is dominated by 3 µm spaced turning marks corresponding to the PSD deviation at 0.3 µm-1 with several superstructures (Fig. 1(a/d)). After photore- sist coating the turning structures were almost fully embedded and a smooth surface is revealed (Fig. 1(b)). As a consequence, the PSD curve is strongly decreased in the spatial frequency range of 0.086 µm-1-34.7 µm-1 and the PSD deviations correspond- ing to the turning marks are almost completely re- moved (Fig. 1d). However, these structures become more apparent if postbaking is applied (Fig. 1c). Due to a shrinkage of the layer during temperature treat- ment the turning marks are transferred into the neg- ative photoresist. On the other hand, the granular structure after exposure is smoothed during heating (see Fig. 1b/c). That may be attributed to flowing of the polymer due to structural reorganization Roughness evolution of the resist surface during RIBE was determined performing stepwise material removal. It could be shown that for removal up to 450 28 100 101 spatial frequency [µm-1] 10-1 aluminium surface coated with ma-N 2405 (before postbake) coated with ma-N 2405 (after postbake) nm the RMS value of approx. 0.26 nm is mainly pre- served. It was also shown, that the etch rate remains constant, if postbaking is applied. Omitting this prep- aration step results in initially higher rates that de- crease with increasing etching depth or etching time, respectively. This behavior may be due to remaining organic solvent in the thin photoresist layer. With in- creasing material removal, the remaining organic sol- vent evaporates resulting in the same steady state etching conditions as the postbaked layer, and an etching rate of 1.1 mm³/h is achieved. Direct RIBE machining was performed on both alu- minium alloys to investigate etching rate and rough- ness evolution. Etch rates have been determined to be 0.54 mm³/h and 0.68 mm³/h for RSA Al6061 and RSA Al905, respectively, which results in etch selec- tivities of 0.53 and 0.61. Fig. 2 shows PSD functions for both tested alloys before and after ion etching. The distinct peaks located between 0.3 µm-1 and 1 µm-1 correspond to the evenly spaced turning marks. After the etching process the waviness and roughness is mainly preserved. However, in the high frequency range, the microroughness increases. From AFM measurements (not shown here) it can be concluded that small particles and granules with diameters of several hundreds of nanometers are formed on the Al905 surface, whereas on the Al6061 surface small etch pits with sizes in the sub-microm- eter range are observed. TOF-SIMS experiments performed in positive mode reveal several alloying constituents in Al905 such as Ti, Ni, Cu, Ga, Fe, Mn, and Mg and Zr. The particles formed on the surface after RIBE machining are mainly due to Cu and Ni waviness / roughness microroughness 1011 ] 4 m n [ D S P c p o r t i o s i n a e m 109 107 105 103 101 RSA Al6061 untreated RSA Al6061 after RIBE RSA Al905 untreated RSA Al905 after RIBE AFM ( 35 µm x 35 µm) WLI AFM ( 3 µm x 3 µm) 10-1 10-3 10-2 10-1 100 spatial frequency [µm-1] 101 Figure 2: PSD functions of RSA Al6061 and Al905 surfaces before and after direct RIBE processing with no resist layer. ULTRA-PRECISION FIGURING AND PATTERNING OF SURFACES REPORTS precipitates that are unevenly distributed over the surface. Significant Si and Mg fractions are foundto-gether within the etch pitson the Al6061 surface [2].After having clarifiedthe individual processes takingplace duringnitrogen irradiation, the planarization of aluminium surfaces hasbeeninvestigated. Resultsfor Al905 are shownin Fig. 3. The initial surface roughness was 9.7 ± 1.6 nm RMS, while the turning markheight was 23.6 ± 0.8 nm. Asshown in Fig.3(a), duringthe first run, the turning marks are re-duced in height by about66.5 % with smoothed edges. Due to a selectivity of 0.52 of the first planar-ization run, the height reductionislarger than ex-pected.The reduction ofthe turningmarkheightmay additionally be enhanced by the ion incidence angle dependent sputter yield asa functionof the local sur-face error slope. Consequently, the roughness fea-tures withhighslopeborder areas may be gradually smoothed. During the second run a further reduction of 44.5% in turning markheightisobservedcorre-lated to aselectivity of0.55. Hence, after two subse-quent planarizationstepsthe final roughness could be decreased down to 5.9 ± 1.1 nm RMS and the turning marks heightshrinked to 4.3 ± 0.5 nm, which isan overall decrease by 82%. However, an increase of the microroughness duringthe process isob-served, asshown in Fig. 3(b). As a result, the surface exhibits a diffusive shine. For applicationsin theVISandUV spectral range a furtherreduction of the in-creased microroughness is prerequisite.Addition-ally, the formed nitride layer hasto be removed. Thus, a subsequention beammachining with1.5 keV oxygen ions wasapplied. Here, the materialremovalwaschosen to be below 10 nm to avoid in-homogeneous matrixstructure effects [3].After RIBE machining withoxygen process gasthe turningmarks remain almost unchanged, whilethe micro-roughness determined in the range isremarkably re-duced.AFM andTOF-SIMSmeasurementsrevealed that particles were reduced and an oxynitride layer of ap-prox. 16 nm thickness isformed on top of the sur-face. Above10 µm-1spatial frequency the PSD curverunseven below PSD curve ofthe untreated surface indicating a smooting in this region [4].Conclusion A processing route for planarization of SPDT alumin-iumsurfaces wasinvestigatedand the underlying mechanisms were elucidated. It could be shown thatthe application oftwo subsequent IBPstepsusing ni-trogenfollowed by an oxygen etching step results in a significantly smoothed aluminium surface over the entire measured spatial frequency range. In additionto the RIBE-based surface figuring technique,thispromisingtechnology enables the smoothing of high-spatial frequency errors of single-point diamond turned aluminium alloyswhile preserving or even im-provingthe initial microroughness.Literature[1]J. Bauer, F. Frost, T.Arnold,J.Phys. D Appl.Phys. 50(2017)085101[2]M.Ulitschka,J. Bauer, F. Frost, T.Arnold,Proc. SPIE11032,EUVand X-ray Optics:SynergybetweenLaboratoryand Space VI(2019)[3]J. Bauer, F. Frost, A. Lehmann,M.Ulitschka,Y.Li,T.Arnold,Opt. Eng. 58(2019)092612[4]M.Ulitschka,J. Bauer, F. Frost, T.Arnold,J.Astron.Telesc. Instrum. Syst. 6 (2020)014001Figure 3: Time dependency of the reflectivity of an epitaxial t-GST thinfilmduringirradiation witha single,20nslaserpulse atfluencesvarying between 12and 50mJ/cm². The ns-laserpulse isapplied att = 0 ns. 0051015202530-20-1001020z[nm]position[µm]10-310-210-110010110-11011031051071091011untreatedN2process (first run)N2process (second run)meanisotropicPSD[nm4]spatialfrequency[µm-1]microroughnesswaviness / roughness10-310-210-110010110-11011031051071091011untreatedN2process(2ndrun)O2processmeanisotropicPSD [nm4]spatialfrequency[µm-1]waviness / roughnessmicroroughnessb)29

REPORTS FUNCTIONAL SURFACES AND THIN FILMS Surface Modification and Electron Irradiation of Nanodiamonds C. Laube, W. Knolle, A. Kahnt, J. Griebel, A. Lotnyk, J. Zhou, A. Prager, B. Abel in collaboration with Y.L. Mindarava, F. Jelezko, Institute for Quantum Optics, Ulm University,Germany J. Wrachtrup, T. Oeckinghaus, A. Denisenko, Institute of Physics, University of Stuttgart, Germany C. Jentgens, Microdiamant AG, Lengwil, Switzerland Introduction Nanodiamonds (NDs) are a rather new member of nanocarbons, and have attracted considerable atten- tion in life sciences since the early investigations on NDs in the late 1990s. The still increasing interest in NDs derives from several superior properties of this carbon nanomaterial, such as the high mechanical robustness, the high content of organic functionali- ties on the particle surface, or a good biocompatibil- ity. Color centers , in particular the NVˉ center, inside the NDs are known to exhibit excellent optical prop- erties for sensory and histological application, such as a low photobleaching, light emission in the long wavelength (up to 850 nm) and long fluorescence lifetimes. Due to the special electronic structure of the NV- center even optical detected magnetic reso- nance, hyperpolarization at room temperature, and magnetic resonance imaging applications were demonstrated in the literature. Even if the large band gap (5.5 eV) of diamond materials suggest it to be inadequate for semiconductor applications, other su- perior properties, such as the high charge carrier mo- bility and heat conductivity still make diamond a promising future material regarding electronic appli- cations, in particular regarding high frequency and voltage devices. Furthermore, NDs derived ma- terial like nanoonions have been demonstrated to be promising material for electrodes and super capaci- tators. Hydrogenated diamonds have been con- firmed to exhibit negative electron affinity in vacuum and surface conductivity when exposed to air. The first ability has been proposed to induce electron emission after UV excitation and is recently investi- gated regarding photocatalytic application. Though the impressive potential of NDs for applications, the large diversity of material properties of NDs hinder the assignment of the observed experimental results. An ”as achieved” ND (GND) sample may variate in several properties, e.g. size, morphology, the quan- tity and kind of color centers inside its lattice, lattice defects, or surface functionality. Furthermore, the NDs may be contaminated with non-diamond carbon or non-carbon impurities. Thus controlled modifica- tion of NDs and the analysis of the ND properties is required, as well as an deeper understanding of the relation between the surface and optical properties 30 of the ND. For these investigations Raman and fluo- rescence spectroscopy, fluorescence lifetime imag- ing microscopy, and pump probe experiments (ns la- ser photolysis) were applied. All surface modifica- tions and optical property investigations were as- sisted by a comprehensive analysis of surface prop- erties of the NDs by applying attenuated total reflec- tion infrared spectroscopy (ATR-IR), X-ray photoe- lectron spectroscopy (XPS), Raman spectroscopy, zeta potential measurements, scanning electron mi- croscopy (SEM), thermo gravimetric analysis (TGA), as well as transmission electron microscopy (TEM). Results and Discussion Modification of Nanodiamonds The gas phase solid reaction has been identified as the most efficient approach for both the efficient degraphitization and functionalization of NDs. A total removal of the unwanted ubiquitous surface graphite could be achieved by the treatment of GNDs in air atmosphere. The total degraphitization of the GNDs could be achieved for a treatment at 590°C and du- ration times up to 16h (Fig. 1). As the properties of the GNDs may vary, these parameters needed to be Samples GND OND HND NND BND C1s [at%] 88.7 88.2 98.2 93.9 98.6 N1s [at%] 0 0 0 3.8 0 O1s [at%] 11.2 10.8 1.7 2.3 1.4 Figure 1: Reaction scheme for the modification of NDs (top), atom content for different modified NDs using XPS (bottom). FUNCTIONAL SURFACES AND THIN FILMS REPORTS determined first by applying TGA in order to guaran-tee the homogeneity of the formed oxidized NDs. These oxydizedND (OND) exhibit a fully degraphi-tizedsurface (as determined by TEM and Raman spectroscopy) with high content of carboxylicgroups leading to a strong negative zetapotential of the par-ticle (ξ <-30 mV). Dueto the homogeneity of the sur-face properties of the ONDs, these particles served as educts for most of the subsequent surface modifi-cations. By applying gassolid reactions utilizing dif-ferent atmospheres, hydrogen or nitrogen termina-tion, as well as a control graphitization of the NDs inArgon atmosphere were achieved(Fig. 1). For the hydrogen terminations of NDs (HNDs), both the tem-perature and treatment time regulate the surface functionalization. At lower temperatures (< 700 °C) and short duration times (<5 h) a still hydroxylated surface was determined, whereashightemperatures promote the partial graphitizationof the surface. The partial graphitized/hydrogenated NDs exhibitdiffer-ent surface propertiesas indicated by a strong posi-tive zetapotential (ξ > +20 mV)compared to non-graphitized HNDs (-20 mV > ξ < +20 mV). In case ofthe nitrogentermination of NDs (NND) at low temper-ature or short treatment times an incomplete oxygen removalwasdetermined. At higher temperature the observation of N=N related vibrationsin the IR-spec-tra indicated the formationof aromaticcomponents on the surface of the NDs. Furthermore, too hightemperatures ledto an unwanted partial hydrogena-tionof the NNDs. For the graphitization of the NDs (bucky NDs, BND), a strong dependence of the formed surface graphite content morphology on the treatment temperature was foundby Raman spec-troscopy.Attemperatures of about 1050°C(argon atmosphere)the ND surface isdefunctionalized and a 2 nm crystalline graphite layer (according to TEM,XRD, and Raman spectroscopy)was formed. The preparation protocolswere standardizedin order to guaranteea propper assignment of the optical prop-erty change to the surface functionality [1].Even ifthe modification of NDs were intensively in-vestigated during the last twenty years, some func-tionalisationse.g. the controlled chlorination of the NDs werestillchallenging. In contrast to wet chem-istry approacheswith the disadvantages of relatively long reaction and purification times and surface con-tamination, a new radiation chemistry approach for the functionalisation of NDs wasestablished [2]. Herein, NDs, in particular HNDs andBNDs, weresuspended in CCl4or otherchloromethane solvents and irradiated with 10 MeV electronsup to a dose upto 1 MGy (Fig.2 top). The highest modification effi-ciency was observedfor HNDs in CCl4(Fig. 2 bot-tom). Accordingto the radiationchemistry of CCl4two possible radicalsare formed as reactants: theCl●andthe CCl3●. Utilizing a theoretical DFT approach and analysisof the chlorinated NDs by in-source thermal desorption mass spectrometry, solely the Cl●was determined to bereactivetowards the hydrogen-ated ND surface, as confirmed by the absence of CCl3●related signalsin the mass spectrum. Further-more, a highstability of the chlorinated surface wasdetermined, so evenmonthsafter the functionaliza-tion, stored under airatmosphere,the chlorinated surface remainsnearly unchanged, and thusisunaf-fected by hydrolysis. The chlorinated NDs offer great potential for subsequent modifications and the demonstrated tha radiation chemistry based modifi-cations open up a new pathway for future modifica-tion of NDs. NV Centers in Nanodiamonds (High-Temperature) Electron IrradiationThe creation of NVˉrequires the presence of twotypes of impurities in the lattice, substitional nitrogen defects (P1 centers) and vacancies. A single va-cancy can recombinewith a P1center to form one NVˉ, provided the presence ofan electron donor(e.g.anotherP1 center). In conventional methods, theva-canciesare createdby irradiation at roomtempera-ture (RT) with high energy electrons, protonsor gamma rays, followed by an additional step of an-nealing (heating up the sample above 800°C). The RT irradiation technique isusually accompanied by the creation of unwanted paramagneticdefects dueto vacancy aggregation (e.g. divacancies and va-cancy clusters). In contrast, performingirradiation at or above the annealing temperature, vacancies cre-atedinstantaneously become mobile and havethe 1

REPORTS FUNCTIONAL SURFACES AND THIN FILMS Figure 3: Eperimental setup for HT electron irradiation in inert atmosphere: quartz tube under the scanning horn (top) and ce- ramic sample holder with diamond powders and bulk diamonds (bottom). possibility to recombine with nitrogen atoms. There- fore, use of this high temperature (HT) irradiation technique is promising for reaching a high conver- sion efficiency from P1 to NVˉ, keeping the concen- tration of undesirable defects low. A procedure for HT irradiation was established at the 10 MeV linac (MB10-30 MP, Mevex) using a special ceramic holder in a quartz tube (Fig. 3), which pro- vides simple temperature isolation as well as the possibility to flush the sample with Argon during the irradiation, preventing oxidation. The heating occurs by means of the energetic beam itself, allowing to reach the desired temperature of 810°C within 2 min (a more gentle increase within 12 min is adopted as standard). Optical properties of NV centers in NDs As mentioned above, the knowledge of the influence of the surface functionality of NDs on their optical properties is of great importance for their applicabil- ity. In order to study this influence a protocol for the well-controlled formation of the NV centers out of the single nitrogen (C center) containing OND was es- tablished via a two-step generation process involving electron irradiation and post-treatment in terms of an- nealing and air oxidation of the NDs (Fig. 4). The flu- orescence properties of NDs containing irradiation- induced NV centers were comprehensively deter- mined regarding the fluorescence intensity, NV0 to Figure 4: NV center generation via electron irradiation and an- nealing in inert atmosphere. 32 Figure 5: Fluorescence of NV center inside nanodiamonds: I) Fluorescence spectra (λex = 532 nm) of NV0/NVˉ centers inside ONDs irradiated with different fluence up to 2×1018 el/cm-2 after post-treatment (annealing at 800 °C in argon and air oxidation at 620 °C), Fluorescence lifetime images of the NVˉ center (longpass filter λ > 700 nm) after excitation (514 nm, pulse width: 60 ps) inside: II) ONDs irradiated with differ- ent fluences and post-treated, III) NDs (irradiated with a flu- ence of 2×1018 el/cm-2 and post-treated) with different surface terminaton (OND, HND and NND). NVˉ fluorescence intensity ratio, and the charge state-related fluorescence lifetime [3]. These proper- ties were investigated dependend on irradiation flu- ences, which is related to the N to NV conversion rate, as well as on the surface functionalities of the NDs (Fig. 5). The following results were obtained: With increasing irradiation fluence all fluorescence properties followed a saturation curve (investigated for OND). Herein, an up to 14-times higher fluores- cence intensity, a factor 1.35 higher NVˉ to NV0 ratio, and an increase of the fluorescence lifetimes from 10 ns up to 25 ns (NVˉ) and 8 ns to 33 ns (NV0) were detected for irradiated ONDs compared to non-irra- diated ONDs. The surface functionality study re- vealed a general decrease of the fluorescence prop- erties in order OND > NND > HND. For irradiated HNDs (final fluence: 2·1018 el/cm-2), a 1.75 times lower NVˉ to NV0 ratio compared to ONDs and a de- creased lifetimes of the NVˉ (11.2 ns) and the NV0 (12.4 ns) were observed. Considering literature re- sults, these trends could be well explained by a quenching effect of single nitrogen center (C center) on the excited state of the NV centers, where the ef- fect is more pronounced for NV0. The effect of the FUNCTIONAL SURFACES AND THIN FILMS REPORTS surface functionalities isrelated to a changed band structure of the NDs towards the particle surface.Optical Properties of Surface functionalized NDs after two Photon Band Gap Excitation The study of the effect ofthe surface functionality on the dynamics of photo-excitedtransients providesvaluable informationfor the electronicand photo-catalytic applicationof NDs. Therefore, NDs with dif-ferent surface terminations were investigated viapump probe experimentsin the ns - µs time range, where the pump (excitation) of the NDs wasrealizedvia a two photon excitation (TPA) at 355 nm or 266 nm in order to overcome thebandgap. Investigations were performed in aqueous dispersions as electron emissionfromthe NDs could beindicated by the for-mationof the solvated electron on the one hand. On the otherhand, diamondsexposed to airatmosphere adsorb a waterfilm at the surface. The highsurface to volume ratio offers a good opportunity to study the surface functionality effects on formed transients. For bothexcitation wavelengths a transient absorptionformationand decay was observedwithin the ns time regime (Fig 6). In case ofOND, avariationof the par-ticle concentration and the applied purging gas lead to the conclusion that the observed transient isre-lated to the formationof separated charge carrierswithin the OND particles. Comparingthe transientdynamics of ONDs, HNDs, NNDs andof platinum decorated NDs (the latter is expected to be an effi-cient electron acceptor andthusa good indicator for attribution of separated charge carriers), a clear trend of increasing transient lifetime was observed in order 𝛕OND(20 ns) < 𝛕PtND(80 ns) < 𝛕NND(210 ns) < 𝛕HND(400ns). The trendcould be explainconsider-ing: a) the electron affinity of the platinum improving the charge separation, and b) thesurface band bend-ingaccording to the surface transfer doping modelleading to a positive surface hole layer after H termi-nation, which aditionally forces a more efficient charge separation. Contradicting to the literature, for excitedHND the electron emissionfollowedby the formationof the solvated electron was not observed in ourcase and itwasdiscussed by meansof doping, surface graphitization, size effects, and the influence of the bandstructure (further investigationin pro-gress). Conclusion The modificationof NDs with an gas-phase-solid re-actionapproach superior to the traditional wet chem-istry was demonstrated.It offers remarkable capabil-ities for the purification of NDs and the controlled functionalization of NDs (H and N termination,sur-face graphite layer). By meansof radiation chemistry an efficient chlorine termination wasobtained. Ra-man scattering on NDswithvariatedsurface graphitecontent demonstrated the effect of graphite en-hanced optical heating on the Raman spectra of the NDs [4]. For the fluorescence propertiesof NV cen-ters insidethe NDs, a clear dependence on the for-mationconditions and the surface functionality was observed. The resultsindicated a fluorescence quenching effect of residual single nitrogencenters (C center)inside the diamondas wellas an effect of the surface functionality in terms of changes of the bandstructure of the NDs. The controlledprepara-tionand comprehensive charactarisation, summa-rized in a PhD thesis[5], is a prerequisiteto future application of NDs. Literature[1]C.Laube,Y. M.Riyad, A.Lotnyk, F. P. Lohmann,C.Kranert,R.Hermann,W. Knolle,T.Oeckinghaus, R.Reuter, A.Denisenko,A.Kahnt, B. Abel,MaterialsChemistryFrontiers1 2017)2527[2]J. Zhou, C.Laube,W. Knolle,S.Naumov, A.Prager,F.D.Kopinke,B. Abel,Diamond Relat.Mater. 822018)150[3]C.Laube,T. Oeckinghaus,J.Lehnert, J. Griebel,W. Knolle,A.Denisenko,A. Kahnt, J.Meijer, J. Wrachtrup,B. Abel,Nanoscale 112019)1770[4]C.Laube,J. Hellweg,C.Sturm, J.Griebel,M.Grundmann,A.Kahnt, B. Abel,Journal ofPhysical ChemistryC 1222018)25685[5]C.Laube,PhDthesis, Leipzig University (2019)3

REPORTS FUNCTIONAL SURFACES AND THIN FILMS From Conductive Self-Assembled Monolayers to Single Molecules on Surfaces M. Glöß, R. Pütt, S. Schmitz, M. Moors, K. Yu. Monakhov in collaboration with R. C. Chiechi, Stratingh Institute for Chemistry & Zernike Institute for Advanced Materials, University of Groningen, The W. Wernsdorfer, Physikalisches Institut (PHI), Karlsruhe Institute of Technology and Institute for Quantum Materials and R. Waser, Peter Grünberg Institut, JARA-FIT, Forschungszentrum Jülich GmbH, Jülich and Institut für Werkstoffe der Technologies (IQMT), Karlsruhe Institute of Technology, Germany Elektrotechnik 2, RWTH Aachen University, Germany Netherlands Introduction The implementation of metal coordination complexes with specific paramagnetic and/or redox properties as single molecules or as constituents of two-dimen- sional (2D) molecular monolayers into computer memory cells is a promising way to keep the minia- turization and sustainability of electronic components from colliding with the so-called “quantum limit” (sub- 10-nm regime) valid. At both these levels of mole- cule–surface interfaces, preservation of the main molecular characteristics as identified in the bulk state, and avoidance of the agglomerative behavior of coordination compounds after their immobilization on solid support constitute important milestones in the controlled micro-spectroscopic addressing of the tunnel junction structures of molecule–electrode hy- brid devices. The eventual step to practical electronic devices mandates an in-depth understanding of the adsorption, autonomous self-organization, electron charge-/spin-transport characteristics and switching mechanisms of mono- and polynuclear complexes of transition metals, lanthanides, and their mixed-metal derivatives on conductive and semi-conductive sur- faces [1]. Paramagnetic Coordination Clusters Two complexes, [Co5(N3)4(N-n-bda)4(bza·SMe)2] (1) and [Co6(N3)4(N- n-bda)2(bza·SMe)5(MeOH)4]Cl (2) where Hbza·SMe = 4-(methylthio)benzoic acid and N-n-H2bda = N-n- butyldiethanolamine, were synthesized and fully characterized by various techniques. Compound 1 exhibits an unusual, approximately C2-symmetric {CoIICoIII4} core of two isosceles Co3 triangles with perpendicularly oriented planes, sharing a central, high-spin CoII ion residing in a distorted tetrahedral coordination environment. This central CoII ion is connected to four outer, octahedrally coordinated low-spin CoIII ions via oxo bridges. Compound 2 comprises a semi-circular {CoII4CoIII2} motif of four non-interacting high-spin CoII and two low-spin CoIII centers in octahedral coordination environments. Self-assembled monolayers (SAMs) of 1 and 2 were polynuclear cobalt(II,III) 34 physisorbed on template-stripped gold surfaces con- tacted by an eutectic gallium-indium (EGaIn) tip. The acquired current density-voltage (I-V) data revealed that the cobalt-based SAMs (Figure 1) are more elec- trically robust than those of the previously reported dinuclear {CuIILnIII} complexes with Ln = Gd, Tb, Dy, or Y [2]. In addition, between 170 and 220°C, the neutral, mixed-valence compound 1 undergoes a re- dox modification, yielding a {Co5}-based coordination cluster (1-A) with five non-interacting, high-spin octa- hedral CoII centers as indicated by SQUID magne- tometry analysis in combination with X-ray photoe- lectron spectroscopy and infrared spectroscopy. Sol- vothermal treatment of 1 results in a high-nuclearity coordination [Co10(N3)2(N-n- bda)6(bza·SMe)6] (3), containing 10 virtually non-in- teracting high-spin CoII centers [1]. Exchange-biased quantum tunneling of magnetiza- tion (QTM) in a transition metal coordination cluster showing single-molecule magnet (SMM) behavior – the characteristics which are relevant for the imple- cluster, Figure 1: Plots of logarithmic current-density against ap- plied potential for the SAMs of compounds 1 and 2. Val- ues of log|J| at V = 0 V are omitted for clarity. The error bars are the 95% confidence intervals. Despite the mi- nor difference in the shape of the J/V curves, the two SAMs are indistinguishable. FUNCTIONAL SURFACES AND THIN FILMS REPORTS mentationof molecular spin qubits in quantumcom-puting – was observed and described [3]. The SMMcompound is the cubane-typeNi(II) complexwith the formula [Ni(μ3-Cl)ClHL·S)]4that iscomposed of the combinationof twocharge-neutralfragments, the {Ni4Cl8} core and fourthio-augmented, pyridyl-alco-hol HL·S ligand(= C11H15NOS)The synthesis, struc-ture, andmagneto-chemistryusing standard SQUID technique (0.1–5.0 T and 2.0–290 K)for thiscom-pound were reported previously [4]. Low-temperature magnetization measure-mentsof [Ni(μ3-Cl)Cl(HL·S)]4 were performed on single crys-talsand they revealedopen hysteresisloopsup to 30 mK at a sweep rate of 0.07 T s−1. The studied mol-eculeexhibits intermolecular antiferromagneticcou-pling interof –0.004K in the supramolecular environ-ment of fourother cubane-type units. Quantum tun-nelingof magnetization characterizedby five stepsat –0.1,–0.05, 0, 0.05 and 0.1 T wasthus detected (Figure 2).The usage of such non-covalent interactionsin net-workingof the individual spin structures of metalcomplexes on surfaces remainschallenging as he interaction with a surface can exert a significant ef-fect on the molecular geometry, electronicstructure and the molecular environment, thusresulting in loss of the pristine magneticcharacteristics. The obtained resultsprompt spectroscopy studieswith regard to the spin structure and spin transport behavior of thisSMMmaterial in the formof supramolecular network on substrate surfaces in the presence of an appliedmagnetic field.Diamagnetic Polyoxometalates The first representativesof phthalocyaninato lantha-nide-ligated polyoxovanadate cages{[V12O32(Cl)]-(LnPc)}–5(= 1 or 2, Ln = Yb3+) were synthesizedand fully characterized. These magneticcomplexes form2D self-assembledmonolayersexhibiting elec-trical conductivity on goldsubstrate surfaces, as as-sessed by using an EGaIn tip (Figure 3). Complexes 1 and 2 are Bu4N+-charged balanced complexes {[VV12O32(Cl)](LnPc)}4–(mono4–) and{[VV12O32(Cl)](LnPc)2}3–(bis3–) where Pcisthe phthalocyanine dianion. These findings offer guid-ance to customizing a hybrid materialthat can be as-sembledof any stablelacunary polyoxometalate core and phthalocyaninatolanthanide moieties. A comparative analysisof the molecular charge transport characteristics of the hybrid materials and their precursors ((Bu4N)4[HV12O32(Cl)] and LnP-cOAc) iscurrently under investigation. The potential possibilitiesof controlled fine-tuning of their struc-tural, electrochemical and magneticcharacteristics in the appliedelectrode environment are expected tomake 2D monolayersof such polyoxometalate-based coordination compounds suitable candidates for practical integration into memory cells. To achievethistechnology transfer-oriented goal, the SAM conductivity switching response to the electricfield ofa scanning probe microscope as a functionof oxidation and magneticstates of metalionsor tem-perature-controlled molecular ordering and/or ad-sorptiongeometry in monolayersare to be explored [5]. The far-reachinginterplay between the speciation of polyoxometalates in the liquid phase andtheirad-sorptioncharacteristics on substrate surfaces yet re-mainsto be understood. The significance of thisin-terplay ishowever paramount because it indicates the degree of technical applicability of solvent pro-–––5

REPORTS FUNCTIONAL SURFACES AND THIN FILMS 5– cessable polyoxometalate molecules. The “polyoxo- metalate–counterion–solvent” and “polyoxomet- alate–counterion–solvent–substrate” processes were elucidated due to the effective combination of small-angle X-ray scattering in solution with surface sensitive scanning tunneling microscopy and X-ray photoelectron spectroscopy measurements (Figure 4). The MeCN-solution speciation of a tris(alkoxo)-li- gated Wells–Dawson-type surfactant carrying mo- lecular charge {[HP2VV3WVI15O59((OCH2)3CCH2OCH2C6H4I)]}– ex- plored as a representative of commonly negatively charged polyoxometalate-based inorganic–organic nanostructures – was strikingly connected with the growth of porous 2D molecular layers on highly ori- ented pyrolytic graphite (HOPG). Low water amounts dramatically transform intermolecular relationships toward hierarchical agglomeration that inhibits the layer formation on HOPG. The obtained findings lay the groundwork for a mechanistic study of controlled nucleation polyoxometalate nanostructures on weakly interacting surfaces [6]. Elaboration of chemical and physical approaches at the level of metal-selective coordination compounds growth and of Figure 4: Deciphering the intricate behavioral properties of polyoxometalates in solution is the key to control and adjust their hierarchical assembly preferences at the na- noscale. The illustration shows such interesting abilities of a typical tris(alkoxo)-ligated Wells-Dawson-type poly- oxoanion to network and to re- and de-clusterize be- tween operational regimes in discrete solutions and on a substrate surface. This finding features the results of combined small-angle X-ray scattering, scanning tun- neling microscopy and X-ray photoelectron spectros- copy experiments that may have far-reaching impact on molecular nano-engineering of polyoxometalate-based devices. 36 Figure 5: The electrical conductivity of a single hexa- vanadate molecule is remarkably dependent on the va- nadium reduction states resulting in several discrete re- sistive states with increasing conductivity at room tem- perature and low operating voltages. as smart successors of common transition metal ox- ide materials that are implemented in today’s com- plementary metal-oxide-semiconductor technology can help achieving the ultimate scalability of ReRAM- based electronic devices, also granting access to not-yet-developed “More than Moore” functionalities. The latter should ultimately allow to overcome a func- tional separation between storage and processing of data as is present in von Neumann architectures characterized by high energy dissipation. The tech- nologically important electron modification using fully-oxidized Lindqvist-type polyoxometalate mole- cules [V6O13{(OCH2)3CCH2SPh}2]2– was explored. These molecules were physisorbed on the Au(111) surface, preserving their structural and electronic characteristics (Figure 5). The resistive switching cell is represented by embedding hexavanadate mole- cules into a model setup, in which the bottom elec- trode is represented by the Au(111) surface and the top electrode is the platinum tip of a scanning tunnel- ing microscope (STM). By applying an external volt- age at room temperature, the valence state of the single polyoxometalate molecule could be changed multiple times through the injection of up to 4 elec- trons. The molecular electrical conductivity is de- pendent on the number of vanadium 3d electrons, re- sulting in several discrete conduction states with in- creasing conductivity. This fundamentally important finding illustrates the far-reaching opportunities for polyoxometalate molecules in the area of multiple- state resistive (memristive) switching [7]. Literature [1] S. Schmitz, X. Qiu, M. Glöß, J. van Leusen, N. V. Izarova, M.A. Nadeem, J. Griebel, R.C. Chiechi, P. Kögerler, K.Y. Monakhov, Front. Chem. 7 (2019), 681 [2] S. Schmitz, A. Kovalchuk, A. Martín-Rodríguez, J. van Leusen, N. V. Izarova, S. D. M. Bourone, Y. Ai, FUNCTIONAL SURFACES AND THIN FILMS REPORTS E.Ruiz, R. Chiechi, P. Kögerler, K. Y. Monakhov, In-org. Chem. 57 (2018), 9274–9285[3]K. Y. Monakhov, W. Wernsdorfer, Mendeleev Com-mun. (2019), accepted[4]V. Heβ, F. Matthes, D.E. Bürgler, K.Y. Monakhov, C.Besson, P. Kögerler, A. Ghisolfi, P. Braunstein, C.M.Schneider, Surf. Sci. 641 (2015), 210–215[5]R. Pütt, X. Qiu, P. Kozłowski, H. Gildenast, O. Lin-nenberg, S. Zahn, R.C. Chiechi, K.Y. Monakhov,Chem. Commun. 55 (2019) 13554–13557[6]M. Glöß, R. Pütt, M. Moors, E. Kentzinger, W. Pyck-hout-Hintzen, K.Y. Monakhov,Nanoscale 11 (2019),4267–4277[7]O. Linnenberg, M. Moors, A. Notario-Estévez, X.López, C. de Graaf, S. Peter, C. Bäumer, R. Waser,K.Y. Monakhov, J. Am. Chem. Soc. 140 (2018),16635–166407

REPORTS MICRO- AND NANOSTRUCTURED MATERIALS AND SURFACES Ion Conductivity Through Polymer Stabilized CsH2PO4 Nanoparticular Layers in Solid Acid Fuel Cells M. Wagner, F. P. Lohmann-Richters, K. Hanus, B. Abel in collaboration with C. Dreßler, D. Sebastiani, Martin-Luther-Universität Halle-Wittenberg, Germany A. Varga, BMW Group, Munich, Germany Introduction Fuel cells based on solid acid proton conductors, known as solid acid fuel cells (SAFCs), are a rela- tively new technology that carry several fundamental advantages [1-3]. An intermediate operating temper- ature of 513 K, at which the electrolyte CsH2PO4 ex- ists in its super protonic phase, allows for fuel fexi- bility and excellent resistance to catalyst poisoning. So far, research has mainly focused on enhancing the activity and interconnectivity of the catalyst, over- looking the resistance of the electrolyte network within a porous powder electrode. This, however, may be limiting the performance, independent of the catalyst utilization. In this combined computational and experimental study, we explore the influence of porous electrodes on cell performance. Therefore, we synthesize three-dimensional, nanostructured, porous electrodes with varying thicknesses using a combination of spray drying and sputtering tech- niques to determine the impact of a porous electro- lyte structure on cell performance. The influence of the stabilizing polymer additive on the average ionic resistivity is then evaluated. AC impedance meas- urements enable us to observe the impact of a CsH2PO4 network on electrode impedance. Meas- urements in a symmetric hydrogen atmosphere and under fuel cell conditions have been conducted and the results compared. Based on an analytical model developed through scanning microscope imaging, we adopted a combined molecular dynamics and lat- tice Monte Carlo approach to the specific morpholog- ical situation. Results and Discussion Materials, cell and electrode fabrication and measurements have been published [4]. The Ki- netic rate model for proton conduction in nano-po- rous systems and details of the cMD/LMC method employed here are described in detail in Ref. 4. Representative SEM micrographs of CsH2PO4 elec- trolyte discs at various stages of sample preparation are presented in Fig. 1. The surface roughness de- creased significantly from before polishing (a) to af- terwards (b), providing a smooth surface for Pt dep- osition via sputtering. Fig. 1(d) shows CsH2PO4 par- ticles deposited onto an electrolyte pellet via spray 38 Fig. 1. Scanning electron micrographs of: a.) as pressed; and b.) a polished CsH2PO4 electrolyte pellet; c.) a cross section of a sputtered Pt thin film; d.) agglomerated pure CsH2PO4 nanostructure deposited via spray drying; e.) a cross section; and f.) a top view of a scanning electron micrograph showing a nanostructured CsH2PO4 electrode with thickness d, stabilized by the polymer PVP and deposited on a dense CsH2PO4 elec- trolyte pellet. Adapted from Ref. 4. drying without the stabilizing polymer PVP. The par- ticles agglomerate rapidly, even in ambient condi- tions. In contrast, the CsH2PO4 structure can be effectively stabilized by adding polyvinylpyrrolidone (PVP) to the precursor solution, as reported previously. Fig. 1 (e, f) shows a PVP stabilized nanostructure on a dense CsH2PO4 electrolyte pellet. In general, particle loading on the surface of the electrolyte pellet in- creases linearly with the duration of spray drying, with a slight variation across the pellet. In the initial stage, only the deposited particle density increases on the pellet surface. Here, we define the area cov- erage of the electrolyte surface as the ratio of the projected area of the deposited particles and the free surface area (between 0, for no coverage and 1 for full coverage). After a mixed stage, when both incom- plete coverage and growth of the layer thickness d occurs, a thick porous layer is established. To quan- tify all stages of nanoparticle deposition, the area coverage was measured with SEM and multiplied with the average thickness of deposited particle clus- ters, yielding the effective layer thickness. The ther- mal stability of PVP and mixtures of PVP with CsH2PO4 and Pt nanoparticles was confirmed using TGA measurements for temperatures below 600 K in both air and nitrogen atmospheres. MICRO- AND NANOSTRUCTURED MATERIALS AND SURFACESREPORTS Representative impedance spectra in the Nyquist formare shownin Fig. 2 for a symmetrical cellwithan effective layer thickness of 2.5 μm anda Pt film thickness of 30 nm. The width ofthe impedance arcs istaken as the elec-trode resistance. The electrolyte resistance, ob-served as a shift ofthe impedance arc along the real axis, issubtracted.For ease of comparison, the re-sultsare converted to area-normalized electrode re-sistances (ANRs). To verify the setup used and en-sure comparability to the literature, Pt thin film elec-trodeswere fabricated and characterizedas de-scribed. The electroderesistances of the thin film electrodes are ingood agreement with the data pub-lished by Louie and Haile[3]. Symmetricmeasure-mentsin a hydrogen environment have often been employedto evaluate electrode structures, since they require less constructioneffort. However, the rate-limiting step for a hydrogen-powered fuel cellisthe oxygen reduction reactionat the cathode. We compare structured and thin film cells insymmetrical andfuelcellmeasurements to analyze whether the structuringisyielding similar activity increases for both techniques. Therefore, two celltypes, differingonly by the electrode type, are compared. “Thin film cells” have 30 nm platinum thin film electrodes on both sideswhereas “porous cells” have two struc-tured electrodes with platinum sputtered on top. All cells have the same platinum content of 0.128 mg cm-². IR-corrected polarization plotsfor cells with Pt thin film electrodes, as well as porouselectrodes underfuelcellconditionshave been de-termined. The cellsshow high reproducibility among themselves. To roughly compare the two characteri-zation techniques, the current density at a voltage of0.5 V istaken for thefuelcellmeasurementsand the mass normalized activity (MNA)iscalculated for the symmetricmeasurement, which represents only the hydrogen oxidationreaction. Both the current densi-tiesas wellas the MNA dependdirectly on the cata-lyst utilization. In Ref. 4 wecompare theaverage cur-rent density at 0.5 V obtained in fuel cell measure-mentsand the increase of the MNA obtained fromsymmetrical measurementsinhydrogen for both electrode types. The standard deviation of the rela-tive increase of the MNA was calculated. First it be-comes clear that structuring an electrode considera-bly increases itsactivity.Through an area increase, the sputtered platinumisdistributed over a larger area, increasingthe active sitedensity. Asmen-tioned earlier, it iswidely assumed, but not proven,that structure-induced improvementsof the anodeperformance observed under symmetrical conditionsare equally viable for thecathode. Since thereaction mechanism of the oxygen reduction isnot yet fully understood, thisassumptionisnot trivial. Second, a similar percental increase resultingfrom structuringcan be seen for both the MNA and current densities. Thisimplies that the electrode structure affects the anodichydrogen oxidation and rate-limiting cathodicoxygen reduction in a similar way,confirmingsym-metricimpedance measurementsas a well-suited methodfor analysing improvementsto the electrodedue to spray drying. The ANR for cells with varying effective layer thicknesses and constant 30 nm Pt thinfilms, are shown in Figure 3. The obtainedeffec-tive layerthickness depends on the spraying time and the exact position of the sample within the dep-osition sectionrelativeto the gas inlet. Therefore, the depositedlayer thickness varies fromcellto cell, as well as over each sample’ssurface. The layerthick-ness of each cellwasmeasured at fourdifferent points and the standard deviation was calculatedas described in the experimentalsection. With the in-creasingamount of spray dried particles, the elec-trode impedance decreased sharply as a result of the increase inthe absolute electrochemically-activesurface area. However, after reaching the lowest ANR at a layer thickness of about 5μm and completearea coverage, electrode resistance increased rap-idly.One should keepinmindthatthisrepresentsonly the optimum for these modelcells which can’tcompete withhigh platinum loading state of the art cells in terms of powerdensity. Asreported by Suryaprakash et al.[5], the platinum depositionviasputtering only penetratesthe top 5 µm of the struc-ture. It seems that the porouslayer significantly in-creases the ANR, given the fact that a maximum18 µm-thick layerwasapplied.AsCsH2PO4itselfservesas a frequency-independent ohmicresistor within the measurement conditionsemployed, the contribution of the porouselectrolyte layer to the ANR is surprising. nmand theeffective layerthickness, 2.5 μm.The elec-39

REPORTS MICRO- AND NANOSTRUCTURED MATERIALS AND SURFACES Fig. 3 Area-normalized electrode resistance (ANR) obtained via AC impedance spectroscopy plotted vs. electrode layer thickness d, showing an optimal layer thickness of ca. 5 μm, followed by an unexpected increase for larger thicknesses. All electrodes had a 30 nm Pt thin film catalyst layer depos- ited via DC magnetron sputtering. Adapted from Ref. 4. In the following sections, an analytical and cMD/LCM model is introduced showing that the observed effect is mainly caused by the porosity and stabilizing agent PVP. By generating constrictions between the sprayed particles, the porous layer develops a fre- quency depending resistance affecting the ANR ra- ther than the purely ohmic electrolyte resistance. For increasing layer thickness a rise in the electrode re- sistance from 0.75 Ωcm² to 7 Ωcm² is observed, Fig- ure 3. Based on SEM images of the porous structure, an analytical model is developed, not to provide precise data but to estimate the impact of the induced poros- ity on the resistivity of the electrode. It will be shown, that the resistance of a pure CsH2PO4 electrolyte net- work, while considering the porosity and constriction effects, fails to explain the observed resistance in- crease by one order of magnitude. For this model, a constant resistivity for CsH2PO4 at 513 K of ρ = 45.45 Ωcm is assumed. A 20 µm-thick dense electrode therefore has a resistance of 0.09 Ωcm². For a porous structure, the tortuosity as well as the porosity influences the resistance. Analysing SEM micrographs of the two highest layer thicknesses shown in Figure 3, the porosity was es- timated to be around 0.5 and the extended proton pathway due to tortuosity to be 1.4 times the layer thickness. For this rough estimate four different re- gions were analysed as described in the experi- mental section. Based on this, a 20 µm-thick porous structure is modelled by circular columns with a total area filling of 50%. According to estimations [4] the resulting area normalized resistance is 0.25 Ωcm². With the resistivity “ρ”, the area of a single column “ACol”, the number of columns per cm² “NCol” and the estimated tortuosity “xt”. Geometric constrictions cre- ated between two adjoining particles of different sizes increase the area-normalized resistance. Tak- ing Figure 4 as a representative image, the smallest 40 Figure 4. Representative SEM micrographs of the generated porous CsH2PO4 electrode network: a.) The dotted lines indi- cate possible pathways trough the porous network. The length is roughly 1.4 times the linear distance. b.) Top view on the porous network. The space between CsH2PO4 particles, which are in roughly the same plane, are colored in red. The area of CsH2PO4 particles compared to the void in one plane is about 50%. Adapted from Ref. 4. constrictions have a diameter of around 300 nm. As- suming ten spherical 300 nm diameter constrictions within a 20 µm layer as an upper limit, the layer re- sistance increases to 0.56 Ωcm², with the length of the constriction “lconst” and the area of the constriction “Aconst”. Suryaprakash et al. [5] report the essential effect of the PVP for the structure’s stabilization, which forms a visible shell around the CsH2PO4 par- ticles during the spraying process for a very high PVP concentration of 10 g l-1. As PVP is not proton conducting, such a shell would act as a barrier ob- structing proton transport. To prove the significance of PVP for the overall resistivity, the electrolyte re- sistances of 500 µm-thick pure CsH2PO4 pellets are compared to a composite cell containing a 500 µm- thick pure CsH2PO4 layer and a 100 µm-thick dense layer of spray-dried CsH2PO4-PVP. The electrolyte resistance increases from 2.5 Ωcm2 for the pure CsH2PO4 pellet to about 7.2 Ωcm2 for the composite CsH2PO4 pellet. The resistivity of the additional 100 µm thick PVP-containing layer is thus 5.0 Ωcm, representing an almost 11 times increase compared to pure CsH2PO4. Assuming this increased resistivity for the calculation, we achieve a resistance increase comparable to the observed. This shows that the ANR’s increase of 6.25 Ωcm2 in Figure 3 between an effective layer thickness of 5 µm and 20 µm can be caused by the additional effect of the PVP stabilized porous electrolyte network. It becomes clear that the porous structure itself makes a significant contribu- tion to the cell’s performance, especially when stabi- lized with PVP. Although further investigations are necessary, it is important to take the thickness of the porous structure into consideration when engineer- ing a high-performance cell. Using a cMD/LMC ap- proach, the current density was calculated as a func- tion of first, the proton insertion rate and second, the system length. The excess proton fraction (EPF) scales with the amount of additional hydrogen atoms attached to near-surface O atoms. Higher EPF there- fore represents a more active surface. For CsH2PO4, MICRO- AND NANOSTRUCTURED MATERIALS AND SURFACESREPORTS the possible numberof protons peroxygen atomrangefrom 0.5 to 1, resultingin a maximumEPF valueof 0.5. Within thisrange, the current density showsa lineardependence [4].According to Ohm’slaw, the current density is proportional to the inverse length of the system. The calculated data fitswell (R = 0.9992) to the expected behaviour. Poroussystems are generated randomly by remov-ingsingle 1x1x2 nm boxes froman 8x8x20 nm CsH2PO4system until a defined porosity isreached. The random removalisrestricted in such a way thatno percolation interruption isgenerated. Examplesfor CsH2PO4systems with different porosities are given in Ref. 4. The conductivity simulations are per-formed for a fixed EPF, correspondingto a constant platinum surface andvoltage.Periodicboundary conditions in x and y directionswere used for all cal-culations. For every porosity,three different calcula-tions of randomly obtained systems were performed and the standard deviationfor both the conductivity and resultingporosity calculated.In the analytical model, theresistance triplesfor a porosity of 0.5 with-out additional geometricconstrictions, and an eight-fold increase isobserved with these constrictions, keeping inmindthatthe numberof geometriccon-strictions were set as an upper limit. The cMD/LMC modelshows a relative increase in the ohmicre-sistance of 4-fold for a porosity of 0.5. The analytical modelwasclosely aligned to the observed porousstructure, whereas the cMD/LMC approach aimed at random porousstructures. Geometrical constrictions are the main reason for the large error, due to the strong negative effect onthe resistivity.It can be con-cluded that the computationalmodelisable to suffi-ciently characterize aporous system, as used in thiswork within the given margin of error. Asmentionedpreviously, the PVP wasfoundto havea highly negativeimpact on the resistivity of CsH2PO4. Suryaprakash et al.[5] reported the ten-dency of PVPto form a shell around the CsH2PO4particle during the spray drying process. With a con-centration ratio of 1:33g l-1between PVP andCsH2PO4, it isreasonableto concludethat PVP doesnot forma uniformouter layer around the CsH2PO4particles but reduces the contact area between twoadjoining CsH2PO4particles. The obstructingeffect caused by the PVP wasmodelled by selectingfourlayersof CsH2PO4along the z axisin an 8x8x20nm system and randomly removingboxes to simulatethe area ofCsH2PO4covered by the PVP. According to thismodel, the increase of the resistivity by a fac-tor of over 10, as observed in our cells, would repre-sent a PVP surface coverage of 94%.Following thisargumentation, at the boundary between PVPand CsH2PO4, a chemical double layer can develop,gen-erating a frequency-dependentresistance. Such a resistance develops an own arc in an impedance spectrogram. In ourcase the impedance arc of the charge transfer reactionat the platinum-CsH2PO4in-terface and from the PVPinduced constrictionsover-lap, leading to a flattened overall impedance arc. Thiseffect isshown in Ref. 4, where the impedance arc symmetry of platinum thin filmelectrodesandpo-rouselectrodesare compared. While thin film elec-trodes show an almost semicircle like symmetry, the arc’sassociated with the porous electrodes are de-formed dueto the additional frequency dependentre-sistance. Conclusion Electrodesare currently the primary performance-limiting component in low and intermediate tempera-ture fuelcells. A proven method for improving elec-trode performance in solid acid fuelcells isto createever finer nanostructures and thus increase the elec-trochemically-active surface area. However, thisper-formance enhancement islimitedby issuesof long-term stability,as well as increasingboth the elec-tronic andionicconduction pathways. Here, we com-bine a systematicexperimentalstudy with a compu-tational modelto quantify the effect of1.) thestabiliz-ingpolymer polyvinylpyrrolidone as well as 2.) the porosity and electrode layer thickness on the aver-age ionicconductivity of the solid acid electrolyteCsH2PO4in a composite solid acid fuel cellelectrode.With a multiscale simulation approach using a com-bined molecular dynamics and lattice Monte Carlomethod, proton conduction through a porous elec-trodeissimulated at mesoscopic timescaleswhile re-taining near-atomisticstructured evolution.Electro-chemical impedance spectroscopy isused to evalu-ate the porous electrodesobtained via spray drying.Bothapproachesreveal a similar and significant con-tributionof the porouselectrolyte layerto the overall cellresistance. Thisindicates that geometrical pa-rameters, aswellas stabilizing materials may play an essential rolewhen designing a high-performance solid acid fuel cell. Literature[1]D.A. Boysen, T.Uda,C.R.I.Chisholm,S. M.Haile,Science (2004) 303,68-70[2]C.R.I.Chisholm,S. M.Haile,Solid State Ionics (2000)136-137,229-241[3]A. Varga, N.A.Brunelli, M.W. Louie,K.P. Giapis, S.M.Haile,J. Mater. Chem. (2010) 20,6309-6315[4]M.Wagner,Ch. Dreßler, F. P. Lohmann-Richters,K.Hanus,D.Sebastiani, A. Varga,B.Abel, J.Mater.Chem.A (2019) 7,27367[5]R.C.Suryaprakash,F. P.Lohmann,M.Wagner,B. Abel,A.Varga, RSC Adv. (2014)4,60429-604361

REPORTS MICRO- AND NANOSTRUCTURED MATERIALS AND SURFACES Spatially Controlled Growth and Immobilization of Peptide Fibrils on Surfaces T. John, J. Bandak, N. Sarveson, C. Hackl, H. J. Risselada, A. Prager, C. Elsner, B. Abel Introduction The assembly of soluble peptide or protein mono- mers into fibrillar supramolecular structures, consist- ing of intermolecular hydrogen-bonded β-sheets, is associated with serious degenerative diseases, such as Alzheimer’s disease, type 2 diabetes, and other misfolding disorders [1-3]. Despite of their physiolog- ical role, amyloid fibrils are promising tools for appli- cations in nanoelectronics, biosensing, and separa- tion technologies [4]. The preparation of amyloid fi- brils in bulk quantities, from readily available low-cost materials, could increase their commercial potential in the near future. The advantage to control the prop- erties of these supramolecular structures by tailoring the primary peptide sequence of the monomers is a unique feature, which enables a high flexibility in ma- terial design. In this study, we have investigated the influence of amino acid substitutions in the primary peptide se- quence of N-terminal modified NNFGAIL peptides (IAPP21-27) on the kinetics and morphology of fibrillar structures. IAPP (islet amyloid polypeptide, amylin) is associated with type 2 diabetes. The identification of residues, which are not needed for fibril formation, could provide suitable targets for the incorporation of functionalities into the peptide, for instance molecu- lar switches, catalytic centers, labels, or functional binding units. The IAPP21-27 peptide (NNFGAIL) is an exception among other steric-zipper amyloid struc- tures reported by the Eisenberg group [1]. We performed thioflavin T (ThT) fluorescence and scanning electron microscopy (SEM) measurements as well as molecular dynamics (MD) simulations to study the role of peptide modifications for the fibrilla- tion kinetics and morphologies [5]. The hydrophobic peptide residues phenylalanine (F23), isoleucine (I26) and leucine (L27) were identified as highly rel- evant for peptide aggregation. Further, Btn- GNNFGAIL fibrils have been successfully immobi- lized on streptavidin coated surfaces [5]. Experimental and Simulations Materials, Peptide synthesis and MALDI-TOF-MS were described in Ref. 5. Structural information for the heptapeptide NNFGAIL was obtained from the Protein Data Bank (entry 3DGJ). MD simulations were performed using GROMACS 4.5.7 and the GROMOS 54A7 united-atom force field at 300 K (see Fig. 1). All peptide bonds were constrained to their equilibrium values using the LINCS algorithm such as described in Ref. 5. Fig. 1. Sequences and structural information on IAPP and IAPP21-27 and their relationship to functional properties. A: Sequence of IAPP with the IAPP21-27 segment of NNFGAIL as the assumed core structural domain for fibrillation (in green). B: Sequence of an IAPP variation found in an Asian subpopulation with accelerated diabetes type 2 (S20G shown in red). C: Studied peptide sequence for alanine scan- ning. D: Surface modification strategy (schematic) for spatial immobilization of biotinylated fibrils. E: NNFGAIL (PDB: 3DGJ) segment from IAPP. Hydrophilic and hydrophobic domains within the protofibril are shown. Molecular data were visualized using the WebGL based 3D viewer NGL from the RCSB PDB website. Adapted from Ref. 5. 42 MICRO- AND NANOSTRUCTURED MATERIALS AND SURFACESREPORTS Results and DiscussionFibril stability of biotinylated GNNFGAIL A peptide system with high aggregation propensity and a biotin anchorfor conjugationof the fibrilsto other structural elementsbased on the biotin-strep-tavidin system was established. Molecular dynamics (MD)simulations were performed in orderto obtaininformationabout the stability and the propensity toformstructural fibrilmotifs in substituted peptides.The study involved the wildtype (wt)peptideNNFGAIL,the negative control NNGGAGL,GNNFGAIL (considering the N-terminal S20Gsub-stitution), and Btn-GNNFGAIL.The MD starting structures consisted of five-stranded protofibrilswith two β-sheets (5x2). In order to moni-tor the stability or disassembly of the modeled pep-tideoligomer structures, the systems were simulated for 100 ns. Structural representations of the protofi-brilsof NNFGAIL,NNGGAGL, GNNFGAIL andBtn-GNNFGAIL after 100 ns are shown in Figure 2a.The fibrilstructure of NNGGAGL was significantly disturbed and not stable. NNFGAIL,GNNFGAIL andBtn-GNNFGAIL had a higher fibril stability. The root-mean-square deviations (RMSD)of the peptidebackbones and the root mean square fluctuations (RMSF) of the peptide residueswere calculated to quantify the stability or disassembly of peptideoligo-mer structures (Figure 2b). The NNGGAGL protofibrilhadthe lowest stability, confirmingthe importance ofthe hydrophobic side chainsphenylalanine (F23)and isoleucine (I26)for peptide fibrilformation. The ex-tension of the wildtype sequence (GNNFGAIL, Btn-GNNFGAIL) enhanced thepeptide fibril stability.In fact, Btn-GNNFGAILhad RMSDand RMSFdevi-ations similar to NNFGAIL; however, the β-sheetswere more stable than for NNFGAIL,and the devia-tions were caused by rearrangementsto achieve an optimized structure. Fibril formation kinetics of alanine scanning variants of Btn-GNNFGAIL To understand the role of single aminoacidswithinBtn-GNNFGAIL for fibrilgrowth and morphology,al-anine scanning of the Btn-GNNFGAILpeptide wascarriedout.Compared to glycine and proline substi-tutions(β-sheet breaker), itisbelieved thatalaninescanning has a reduced impact on the peptideback-bone, which isimportant for NNFGAIL-derivedpep-tides since theirfibrillationis promoted by backbone-backboneinteractions of the individual strands(Fig-ure 1E). The kinetics of amyloidfibrilformationwas followed using ThT binding assays[5]. The datashow the fluorescence intensity after several time in-tervalsunderidentical ambient conditions for each peptide(temperature, shakingintensity). Consider-ingthe value after one day ofincubation, the peptidevariants. Btn-GNN(F23A)GAIL,Btn-GNNFGA(I26A)L, Btn-GNNFGAI(L27A), and Btn-GN(N22A)FGAIL had a reduced fluores-cence intensity compared to theother peptides. Thissuggests that the residues F23, I26, L27and N22 are important for theformationof β-sheet rich nuclei that seed fibrilformation. After one month of incubation, significant fluorescence signalswerefoundin all samples, exceptof Btn-GNNFGA(I26A)L. The long-est lag times of fibrillation were observed for the var-iants Btn-GNN(F23A)GAIL and Btn-GNNFGAI(L27A). Morphologies ofalanine scanning variants of Btn-GNNFGAIL The peptidefibrilmorphologiesafter 1 d and17 d were studied by SEM (Figures 5 andS3). After 1 d, large amountsof fibrils were formed for almost all al-anine scanningvariants, when dried on silicon wa-fers, with the exception of Btn-GN(N22A)FGAIL, Btn-GNN(F23A)GAIL and Btn-GNNFGAI(L27A). In these cases, mostly amorphouspeptide aggregatescover the surface of the silicon wafers, which have a tendency to arrange in a more or less non-ordered phase. Btn-(G20A)NNFGAILand Btn-G(N21A)NFGAILformed thinner fibrilstructures, while Btn-GNNF(G24A)AIL, Btn-GNNFGAIL andBtn-GNNFGA(I26A)L thicker ones. The morpholo-giesof the supramolecular structures differ fromma-ture NNFGAILfibrils. NNFGAIL forms extremely dense fibril associates with a crystal-like superlattice and a highdegree of stiffness (Fig. 3). In contrast, single fibrils of Btn-(G20A)NNFGAIL are arranged in 3

REPORTS MICRO- AND NANOSTRUCTURED MATERIALS AND SURFACES for the to of fibrils was changed observed Btn-(G20A)NNFGAIL, flexible ring shaped structures, which can be com- pressed to tight gels (Figure 3). The stiffness ap- pears dramatically reduced. The same feature was ultimately found for the Btn-GNNFGAIL, indicating that the N-terminal modification has a high impact on the morphology of the fibrils, which is likely based on their intrinsic flexibility. After 17 d, the morphology slightly peptide Btn-G(N21A)NFGAIL which formed needle-like fi- brils, which was not obvious after 1 d. A much higher amount for Btn-GNNFGA(I26A)L after 17 d with a comparable morphology Btn- GNNFGAIL, and Btn-GNNF(G24A)AIL. The double variant Btn-GNN(F23A)GA(I26A)L formed no fibrils, even after 17 d. For Btn-GNNFGA(I26A)L, no fibrils were found in the ThT fluorescence assay after 1 d, while SEM revealed some fibrillar structures. This is likely caused by surface concentration effects during sample preparation for SEM. While the peptide con- taining droplets air-dried on the silicon supports, the peptide concentration increased, which increased the propensity for peptide aggregation. Our results indicate that the substitution of F23A has a large negative impact on the formation of mature fibrils. Thus, F23 is a key residue for the aggregation of Btn-GNNFGAIL. This result is consistent with pre- viously reported MD simulations, where glycine scanning variants of the wildtype NNFGAIL were studied to understand the effect of single point sub- stitutions on the amyloidogenic propensity in terms of the sheet-to-sheet and strand-to-strand interac- tions. In agreement with our experimental results, the variants NN(F23G)GAIL and NNFGA(I26G)L had a lower fibril stability followed by (N21G)NFGAIL and N(N22G)FGAIL. Our findings also agree with previ- ous observations when IAPP (segment) mutations were the variants N(F23Y)GAILSS, SN(N22P)FGAILSS, SNNFGA (I26P)LSS and SNNFGAI(L27P) aggregated to a lower extent. No or a reduced amyloid fibril formation was observed under experimental conditions when phenylalanine was replaced with alanine in full- length IAPP and selected peptide segments. A sum- mary on the influence of amino acid substitutions in IAPP and derived peptides from previous studies is provided in Ref. 5, emphasizing the role of each res- idue. Theoretical predictions Theoretical predictions based on the contribution of each amino acid in GNNFGAIL to the overall solubil- ity and propensity to form fibrillar aggregates re- vealed that the F23A variant had the largest impact, followed by I26A and L27A. These calculations are investigated. For instance, 44 Fig. 3 SEM images of fibrils of the alanine scanning peptides of Btn-GNNFGAIL after 24 h ([peptide] in the fibrillation assay = 0.1 mg/mL). Adapted from Ref. 5. in agreement with the experimental results obtained in the ThT kinetic assay and SEM measurements for Btn-GNNFGAIL, confirming the high relevance of the phenylalanine, isoleucine and leucine residues for peptide fibril formation, especially its early nucleation phase. A lower solubility and higher aggregation propensity were found for the G20A, N21A, N22A and G24A variants compared to the unmodified GNNFGAIL peptide, in agreement with the ThT assay. One out- lier between the predicted solubility for GNNFGAIL variants and the experimentally observed amyloid formation for Btn-GNNFGAIL after 1 d is the N22A variant. Although this variant is poorly soluble, it did not form many fibrils. This is likely due to a kinetic effect, increasing the lag time for the formation of a critical nucleus, until large amounts of fibrils were formed after 3 d. Immobilization to streptavidin coated sur- faces Fibril-modified surfaces are of interest for different purposes, for instance their usage as a new class of morphologically and chemically engineered bio- materials, which may be involved in fibril-cell or fibril- nanoparticle interactions. Since the amount of bio- logical sample materials is limited, microfluidic ap- proaches are readily advantageous over conven- tional laboratory techniques. The spatially controlled immobilization of fibrils to surfaces is the first step to- wards their integration into multifunctional microflu- idic systems [6]. A streptavidin coated glass slide was used as a model to demonstrate the spatial im- mobilization of biotinylated fibrils to surfaces as a first proof-of-concept; however, even other binding con- cepts may be suitable. To achieve the goal, the streptavidin coated slide was exposed to an atmospheric oxygen plasma through a mask allowing for streptavidin inactivation MICRO- AND NANOSTRUCTURED MATERIALS AND SURFACES REPORTS and degradation at the exposed areas. Different sur-face modification techniques, such as laser structur-ing, could also be applied at this stage. After treat-ment, exposed and unexposed areas were incubated with a peptide solution of Btn-GNNFGAIL under fibril-lation conditions (Figure 4). SEM revealed a higher degree of immobilized fibrils in the streptavidin coated areas, whereas plasma-cleaned areas showed a much lower degree of bound fibrils (Figure 4). Instead of a homogeneous surface coverage, the fibrils formed islets of a few tenth of micrometers (Figure 4c). The herein presented approach is highly compatible with our recently developed method of in-verse microfluidic printing (cryoprinting [6]). Cry-oprinting enables the fabrication of microfluidic sys-tems on a time scale of a few minutes by aqueous printing and freezing of microstructures using the drop-on-demand technology, which are subse-quently encapsulated in a photocured polymer within milliseconds. Fibrillar nanostructures and their gels could thus be integrated into microfluidic systems un-der spatial control in the near future [6].Conclusion Key residues for fibril formation of the N-terminal bi-otinylated IAPP21-27 peptide (Btn-GNNFGAIL) were identified using an alanine scanning approach com-bined with molecular dynamics simulations, thiofla-vin T fluorescence measurements, and scanning electron microscopy. A significant contribution of phenylalanine (F23) for the fibrillation of the short peptide segment was identified. The fibril morpholo-gies of the peptide variants differed depending on their primary sequence, ranging from flexible and semi-flexible to stiff and crystal-like structures. These insights could advance the design of new functional hybrid bionanomaterials and fibril-engineered and coated surfaces using short peptide segments. To validate this concept, fibrils were immobilized on streptavidin coated surfaces under spatial control.Literature [1]D.Eisenberg, A. D. McLachlan, Solvation Energy in ProteinFolding and Binding, Nature (1986) 319 (6050), 199–203[2]T. John, A Gladytz, C. Kubeil, L. L. Martin, H. J. Risselada,B.Abel, Nanoscale (2018) 10 (45), 20894–20913[3]A. Gladytz, B. Abel, H. J. Risselada, Angew. Chemie - Int.Ed. (2016) 55 (37), 11242–11246[4]J. Bandak, J. Petzold, H. Hatahet, A. Prager, B. Kersting,C.Elsner, B. Abel, RSC Adv. (2019) 9 (10), 5558–5569[5]T. John, J. Bandak, N. Sarveson, C. Hackl, H. J. Risselada,A.Prager, C. Elsner, B. Abel, Biomacromolecules (2020) 21,2, 783-792[6]C. Elsner, et al., Verfahren zur Herstellung eines Mikrosystembauteils, DE Patent 102017130947.0 (A1), Dezember 21,20175

REPORTS MOLECULAR MECHANISMS ON SURFACES AND INTERFACES Photoemission Electron Microscopy – a Tool Analyzing the Polymer Surface Morphology F. Niefind, A. Neff, S. Karande, F. Frost, B. Abel, A. Kahnt in collaboration with S.C.B. Mannsfeld, Center for Advancing Electronics Dresden (cfaed), Technische Universität Dresden, Ger- many The Bigger Picture The energy consumption of the world is rising since decades and is reaching new highs nearly every year. The most of this energy is still originating from non-renewable sources such as burning oil, natural gas and coal, which all contributes to the human car- bon dioxide footprint with foreseeable and already recognizable harmful impact on the worlds ecosys- tem. The challenge minimizing these adverse effects in the future is the transition of the economy away from the consumption of fossil fuels towards the us- age of sustainable sources, which are renewable. As it is foreseeable, solar light to power conversion will make a major contribution to achieve this goal. Major successes were already attained in the past, utilizing very efficient silicon or perovskite based solar de- vices. However, such devices are impractical in ap- plications where other properties such as semitrans- parency or mechanical flexibility is a major factor. Here devices based on semiconducting polymers are emerging as feasible candidates and thus the deter- mination of the nanoscale structure of polymer films becomes a key factor. Introduction Semiconducting polymers have drawn attentions in the scientific community since several decades and are assumed as promising candidates for organic transistors, organic light emitting diodes and organic photovoltaics. In the case of the latter – organic pho- tovoltaics – semiconducting polymers will have its niche in applications where the mechanical flexibility is a necessary feature e.g., in the emerging field of wearables. The flexibility and efficiency of organic photovoltaic devices is dictated by the sub-microme- ter morphology of the polymer film. As a rule over thumb, on the one hand side, the more crystalline and well aligned the polymers are, the more efficient is the overall light to power conversion. On the other hand side, the more random the polymers are coiled, the more flexible the film is, but such films exhibit lower light conversion efficiencies. In order to control the polymer film structure, a technique is required that enables to image the morphology on the na- nometer and micrometer scale. Photoemission Elec- tron Microscopy (PEEM) has emerged as techniques that enables the determination of the morphology on the relevant scale. Furthermore, PEEM is a fast and 46 in particular non-destructive technique making it su- preme over other approaches like near edge X-ray absorption fine structure spectroscopy (NEXAFS), scanning transmission X-ray microscopy (STXM) or polarized X-ray scattering (PoXS). As a microscopic technique, PEEM delivers images of the photoelectron intensity, and when measured with polarized light the intensity contains information on the orientation of the polymer chain. In order to make the chain orientation obtained from PEEM im- ages of different samples comparable; a method is needed that allows breaking the orientation infor- mation from PEEM images down to a single value or a simple graph. In the following we report on our pub- lished results establishing the orientation persistence length (OPL) as a measure for the order of polymer films and with this information on hand, we report on the solvent influence on the surface morphology in spin coated P3HT thin films. [1,2] Results As already shown in the past, polarized light, e.g., originating from a laser allows the imaging of the morphology in polymer films in respect of their chain orientation and local degree of order. [3] As an ex- ample regioregular poly(3-hexylthiophene-2,5-diyl) (RR-P3HT) was chosen and spin-coated on silicon wafer and FTO-coated glass. The PEEM measure- ments of both samples (figure 1) exhibited domains in the micrometer range with polymer chains with a similar orientation. However, even by eye it is clearly visible that the domains of similar order are smaller for the polymer coated on FTO compared to the do- main sizes for the Si based sample (compare figure 1a and 1c). As a way to quantify this by eye visible difference in the PEEM images, the orientation persistence length was used in order to determine the average distance starting from a random pixel in the PEEM image until the change of the polymer chain orientation is over- coming a selected threshold angle Δβ. For both PEEM images (figures 1a and 1c) 10000 pixels from the centers of the images – to avoid boundary effects – were randomly selected and the chain orientation for every of this pixel was determined. Than for every pixel in a random direction the distance to the first pixel where the chain orientation differs more than the threshold angle Δβ was determined. The average MOLECULAR MECHANISMS ON SURFACES AND INTERFACES REPORTS values obtained for different selected threshold angle Δβfor both samplesisshown in figure 2 depictingclearly substantially largerorientation persistence length values– independent from the selected threshold angleΔβ– for the RR-P3HT spincoated on Si.With the OPLas a measure to quantify the order of polymer chains from PEEM imageson hand, the in-fluence ofthe solvent fromwhich the films were spunwas investigated. Previous literature published re-sultsindicated a strong solvent dependence on the polymer film morphology and film quality.[4] Especially the boiling point of the solvent from which the films werespun was assumed as the dominating factor for the film quality – in terms of ordered struc-ture size – and the performance ofthe devices madefromit. The rational for this is that films obtained fromsolutions withsolvents of higher boiling pointswill ex-hibit higher crystallinity since the higher the boiling point, the longer isthe evaporation period andthusitgrants the polymer more time to arrangein a crystal-line morphology. However, when measuringPEEM imagesfor RR-P3HTfilms spunfromdifferent or-ganicsolvents with boiling points ranging from 60 to 214°C derivations fromthistrend were obvious. Asone can already see by the eyefromthe PEEM im-agesin figure 3, the size of the domainswith the same orientation in thiophene and chlorobenzene islargerthan in 1,2,4-trichlorobenzen, even though the boiling point of 1,2,4-trichlorobenzeniswith 214°C Δβ7

REPORTS MOLECULAR MECHANISMS ON SURFACES AND INTERFACES higher than the boiling point for thiophene (84°C) and chlorobenzene (132°C). This finding is strongly con- tradicting the notion that the boiling point is the (ex- clusive) key factor determining the film crystallinity. Noteworthy is the fact that for all solvents it is clearly visible that the domain size and therefor the crystal- linity is increased when the films were spun from so- lutions at elevated temperatures. Bearing in mind that with the elevation of the temperature also the solubility increases, this finding indicates that the sol- ubility of P3HT in the selected solvent contributes to the domain size in the films. Using the OPL as a measure for the crystallinity of the films figure 4 depicts the correlation between the OPL and the P3HT solubility. As a general finding – disregarding chloroform – one sees an increase of the OPL with increasing solvability of P3HT. Chloro- form however shows rather small domains and is a clear outliner breaking this global trend, and requires separate considerations. Compared to the other sol- vents used, chloroform exhibits a much higher vapor pressure, which leads too much shorter drying times, leaving the polymer chains less time to aggregate properly and thus resulting in smaller domains of the same orientation. These findings stresses clearly that the polymer film morphology depends on multi- ple factors and the solvability of the polymer together with the boiling point, seems to be a substantial if not the key factor controlling the domain size and the overall film morphology. Conclusion In conclusion, we report on a method, which allows to quantify the average domain size and thus the crystallinity of polymer films from PEEM images taken with polarized light. With this method on hand further key factors dictating the polymer crystallinity for spin coated films were determined. Experimental Section All PEEM measurements were performed in an IS- PEEM from FOCUS GmbH with an ultimate resolu- tion of ≈ 40 nm. The laser radiation was generated with a Coherent Fidelity-2 laser. The fundamental wavelength (1070 nm) was frequency doubled to 535 nm by an APE Harmonixx. The samples were illumi- nated using a normal incidence rhodium mirror inside the Focus PEEM. The polarization direction and the pulse energy were adjusted by a combination of a λ/2-waveplate and a polarizer. For the presented measurements the laser power was set to 17.5 mW before entering the vacuum chamber through a win- dow, except for chlorobenzene, where the laser power used was 10 mW. For further details see Ref. 1 and 2. Acknowledgement The work was funded in part by the German Science foundation (DFG) through SFB-TR102. Dr. Falk Niefind gratefully acknowledges funding from the DBU. Dr. Andreas Neff was funded by the Beilstein- Institut zur Förderung der Chemischen Wissenschaf- ten. Prof. Dr. Bernd Abel thanks the Miller Institute of the UC Berkeley for a Somorjai-Miller-Guest-Profes- sorship Award 2018. Dr. Axel Kahnt and Prof. Dr. Bernd Abel thank APE Angewandte Physik und El- ektronik GmbH for support with the Harmonixx. All authors are deeply indebted to Dr. Katrin Siefermann for her contributions in the early stages of this pro- ject. The authors thank Dr. Mike Hambsch for insight- ful discussions concerning the film preparation. Figure 4: Dependence of the OPL for Δβ = 20° plotted against the solubility of P3HT in different solvents. The values repre- sent the mean value gathered from multiple spots on the same sample. The error bars express the standard deviation (F. Niefind, S. Karande, F. Frost, B. Abel and A. Kahnt, Na- noscale Adv. 1, 3883 (2019) - Published by The Royal Society of Chemistry). 48 Literature [1] F. Niefind, A. Neff, S. C. B. Mannsfeld, A. Kahnt, B. Abel, Phys. Chem. Chem. Phys. 21, 21464 (2019) [2] F. Niefind, S. Karande, F. Frost, B. Abel and A. Kahnt, Na- noscale Adv. 1, 3883 (2019) [3] A. Neff, F. Niefind, B. Abel, S. C. B. Mannsfeld, and K. R. Siefermann, Adv. Mater. 29, 1701012 (2017) [4] H. Yang, T. J. Shin, L. Yang, K. Cho, C.Y. Ryu, Z. Bao, Adv. Funct. Mater. 15, 671 (2005) TOOL DEVELOPMENT: PLASMA AND ION BEAM SOURCES SELECTED RESULTS TALIF Diagnostics of RareGasDensitiesin GriddedIon SourcesC.Eichhorn, F. Scholze, C. Bundesmann, D. Spemann, H. Neumannin collaboration with H.Leiter, ArianeGroup GmbH, D-74239 LampoldshausenThe knowledge of neutral particle densitieswithin or near the exit plane of gridsystems isof substantial importance for the estimationof the lifetime of grid-ded ion sources. In two-grid ionoptics, the impinge-ment ofsecondary ions, produced in charge ex-change processes between primary ions and thermal neutral particles, onthe accelerator gridiscommonly known as the maincause of grid erosion.Long grid lifetimes are essential for the design of ion optics for electricspace propulsion, where multi-year operationof gridded ionthrusters isrequired to achieve mis-sionobjectives of orbiting satellites or interplanetary probes. Two-photon absorption laser induced fluorescence (TALIF)spectroscopy isa powerful non-intrusive di-agnostictechnique to measure ground state densi-tiesof atoms or molecules[1]. Since in many low-temperature plasma applications the depletion of the ground state may be neglected, the methodallowsfor a direct measurement of neutral particle specieslike xenonor krypton, which are common process gases in surface engineering, as wellas propellants for space applications. The principleof the methodisthe spatially resolved state-selectivetwo-photon ex-citation of the plasma speciesof interest usingthe output ofa Nd:YAG pumped dyelaser, and detectingthe subsequent fluorescence witha photomultiplier, which is processed in a boxcar integrator (Fig. 1). Measurementsusing a newly installedTALIFset-up at IOM have recently beencarriedout in the plume of the ionthruster RIT-10, which has been providedby ArianeGroup GmbH [2,3]. Anexample of a radial profile of the neutral density of krypton inthe plume of the thruster measured with TALIF isshown in Fig.2.Ascan be seen, the neutral density inthe plumecan be clearly resolved from an offset, which resultsfromthe krypton background density in the vacuumchamber. The set-up allows for an analysisof thelineshape ofthe absorption line, aswell as of the life-time of the excited level, which ismeasured using afast oscilloscope of 1.5 GHz bandwidth.Besides such axial and radial neutral density map-ping in xenon and krypton,further investigations deal withthe applicationof the TALIF methodon the plasma inside the discharge chamberof gridded ionsources. Here, in experimentsusing the institute-built ISQ40 RF source equipped with quartz glass cham-berwalls, quantitative TALIF spectroscopy on neutral particle densities has been demonstrated.Financial supportfromthe Deutsche Forschungsge-meinschaft DFG through grant EI978/1-1 is gratefully acknowledged. Literature[1]D.J.Bamford,L.E. Jusinski,W. K.Bischel,Phys Rev A 34(1986)185[2]Eichhorn,C., Scholze, F., Bundesmann,C., Spemann,D.,Neumann,H., Leiter, H., J.Propul. Power35(2019)1175[3]Eichhorn,C., Scholze, F., Bundesmann,C., Spemann,D.,Neumann,H., Leiter, H., 36th International ElectricPropul-sion Conference,Wien,IEPC Paper-2019-503, 2019Figure 1:TALIF experimental set-up. Figure 2:Radialneutral densityprofile in theplume oftheRIT-10, includingtime- and spectrallyresolvedsignals. 49

SELECTED RESULTS TOOL DEVELOPMENT: PLASMA AND ION BEAM SOURCES Setting up a New Laboratory for Plasma Engineering A. Anders, C. Bundesmann, W. Diyatmika, C. Eichhorn, U. Gey, D. Kalanov, J. Knipper, K. Oh, T. Pröhl, M. Rudolph, Spemann, Y. Unutulmazsoy, R. Woyciechowski Plasma and ion beams are often used to assist in physical vapor deposition in order to obtain films or nanostructures with the desired properties. Those properties are the result of the intrinsic material prop- erties and the micro (and nano) structure. For plasma-assisted deposition, it seems obvious that the plasma should be engineered but in practice the plasma source is often used “as-is” and the effects are primarily tuned via substrate bias affecting ion and electron fluxes to the substrate. Therefore, to have a better control over the final properties of sur- faces, coatings, and nanostructures, a lab is set up in which the engineering of the plasma is at the cen- ter of future research activities. This is done with sur- face effects being monitored, too. In other words, the activities at the lab aim to simultaneously diagnose and adjust the properties of the plasma (such as the flux of ions to a substrate in terms of energy and charge states) and monitor plasma effects on sur- faces and films. As model plasma sources we have set up a high power impulse magnetron (HiPIMS) source, which will be supplemented in 2020 with pulsed filtered arc sources. The Plasma Lab, located in 17.1/0.06, occupies the formed BN-MBE lab, which has not be operational for some time. In 2018/19, the outdated equipment was removed and the room prepared to accommodate three vacuum chambers, two of them were put in ser- vice by the end of the reporting period (Fig. 1). The large chamber has been named “pi-PVD” (pulsed ionized physical vapor deposition) since its main purpose is to expand the established technique Figure 1: Vacuum chamber “pi-PVD” in the new Plasma Lab, December 2019 50 Figure 2: Vacuum chamber for SAB-Project “Modular Plasma Deposition Platform”, designed in 2019, to be manufactured and installed in 2020. of “i-PVD” to a pulsed system, thereby opening new process parameters (high pulse power, adjustable pulse length, duty cycle, pulse reversal). The concept of “pi-PVD” is the basis for a project of the “Leibniz Collaborative Excellence” that was jointly prepared with the RWTH Aachen University. In this project, which started in 2019, we plan to study the effect of ion charge on the microstructure and properties of compound films such as VAlN. The second chamber, which is much smaller, is designed for preparatory experiments, including high power impulse magne- tron sputtering (HiPIMS); it will also be used for the training of graduate students. The third vacuum chamber, funded by a grant of the SAB, has been designed (Fig. 2). This chamber is specifically designed to simultane- ously accommodate plasma diagnostics and surface measurements, therefore a large set of carefully se- lected ports had to be placed. With these preparations, and the acquisition of mod- ern diagnostic equipment, the Plasma Engineering Group is positioned to execute various projects, most notable the Leibniz Collaborative Excellence and the SAB-funded project. THIN FILMSWITH NANO- AND ATOMIC STRUCTURES SELECTED RESULTS HighlyPorous Silver Thin Films for Biosensing Applications C.Grüner, S. Grüner, B. Rauschenbachin collaboration with I.Abdulhalim, Ben-Gurion University of the Negev, IsraelPrecious metalthin films, generated by Glancing An-gle Deposition (GLAD), provide highly unique physi-cal properties. One of these propertiesisthe extreme enhancement of specificoptical effects, which can be taken advantage of for sensing applications [1].While effects like surface enhanced Raman scatter-ing(SERS), surface enhanced fluorescence (SEF), and surface enhanced infrared absorption (SEIRA)can also be foundin the vicinity of smooth,compact metalfilms, GLAD films on the one handexhibit a very highporosity andlarge effective surface area, which maximizes the contact between the test me-diumandthe metalitself. On the otherhand,GLAD films consist of very thin nanostructures. This further increases i.e. the Raman efficiency due to the strong electricfield observedclose to thehighly curvedsur-faces of such nanostructures. GLAD, inprinciple, isa straightforward technique.Deposition equipment and conditions are used thatare common with most physical vapour deposition (PVD) techniques. The main difference isthat the materialfluxdoesnot arrive at normal incidence at the substrate, butinstead in a highly oblique manner. Thisleads to a geometricself-shadowingeffect dur-ing deposition, which finally yieldsthe self-organized growthof nanostructures on the surface. The shapeof the nanostructures and the integral propertiesof theporous thin film can be controlledby the deposi-tiongeometry (angle of incidence, substrate rotation) and the usual PVD parameters (like materialflux, substrate temperature or residual gas pressure). The extremely high enhancement factors, achieva-blewith Ag GLADfilms, are in the 1010range and a possibility to make these films specificto a previously chosen test agentismandatory. Thiscan be accom-plished by further surface functionalization with anti-bodies or bacteriophages. In Figure 1 theSERS sig-nalintensity measurement of E. colibacteria isshown. The sensor consists of a 350 nm thick Ag film witharound30% overall porosity.Specificity ispro-videdby applying bacteriophages. The resultsre-veal, thatalready smallconcentrations, down to 1 bacteriumper10 µl volume can be safely detected. Otherthan the targeted bacteria strains do not lead to achangein signal intensity,demonstrating the se-lectivity of this sensor type. Optimization of such sensors requires fundamentalknowledgeof the underlying growth processes. On one side, the growth process itselfmust be studied. Thisisrealized by accompanying computer simula-tions(see Figure 2) andtheoreticmodelling[2]. Anunderlying general relationship could already be found, that links the angle of incidence with morpho-logical filmparameters, such as porosity.On the other side, material properties strongly influence the GLAD process. Therefore, GLAD metalfilms have been intensively studied.It could be shownthat for most metals a growth temperature window exists, in which the nanostructures grow single crystalline, forming a biaxially textured porous thin film [3].Literature[1]C.Grüner,I. Abdulhalim,B.Rauschenbach,Encyclopedia ofInterfacial Chemistry, Editor: K. Wandelt, Elsevier:Oxford.(2018) pp. 129[2]C.Grüner,S. Liedtke,J.Bauer, S.G.Mayr, B.Rauschen-bach,ACSAppl.NanoMater. 1 (2018)1370[3]S. Liedtke-Grüner,C. Grüner,A. Lotnyk, J.W. Gerlach,B.Rauschenbach,Phys. Stat. Solidi A 217 (2020)190063Figure 1:SERSsignal intensityobtainedatdifferent concentra-tionsofvariousbacteria strainsusing Ag GLAD films. Figure 2:Computersimulations oftilted(left) and upright (right) nanostructures, grown under oblique material incidence withoutand with substrate rotation,respectively.1

SELECTED RESULTS ULTRA-PRECISION FIGURING AND PATTERNING OF SURFACES Reactive Ion Beam Etching of Highly Dispersive, High-Efficiency Transmission Gratings for the VIS Range A. Finzel, G. Dornberg, F. Frost in collaboration with F. Koch, D. Lehr, T. Glaser, Carl Zeiss Jena GmbH, Germany With the growing importance of ultrashort pulse la- sers the demand for particularly tailored optical com- ponents arises. Different dispersive elements can be utilized for the temporal stretching and recompres- sion of short pulses. Transmission surface relief grat- ings in fused silica are particularly popular due to their high-laser-induced damage threshold as well as the ability to utilize them in the Littrow configuration [1]. For the realizationn of the monolithic transmission gratings with 3000 L/mm the resist-coated and soft- baked fused silica substrateswere exposed to the stabilized interference pattern and afterward wet- chemically developed [2]. The optimizedresist profiles show no residual resist layer left at the grooves and a sufficiently large duty cycle of 0.4 [2]. Typical resist profiles show no resid- ual resist layer left at the grooves, a height of 280 nm and a duty cycle (ratio between ridge width and pe- riod) of 0.4. The pattern transfer of the resist profile into the fused silica substrate was performed by re- active ion beam etching (RIBE) [3]. A commercially RIBE plant equipped with a broad beam Kaufman- type ion source was used. The ion source was oper- ated with a beam voltage of 700 V, resulting in an ion energy of 850 eV (discharge voltage: 150 V) and a beam current of 70 mA. The chosen gas mixtures were 3.75 sccm CHF3 / 0.94 sccm Ar / 0.31 sccm O2, and 4.06 sccm CHF3 / 0.94 Ar to achieve a high se- lectivity. The acceleration voltage of the ion source was set to −100 or −1000 V to study the effect of dif- ferent angular distributions of ions within the broad beam. Comparing the etch gas mixture with oxygen (sam- ples A, C, and E) and without oxygen (B, D, and F, see Figure 1), it can be seen that the duty cycle of the structures is smaller when the etching was per- formed with oxygen. The reason for this is the faster degradation of the photoresist and its higher lateral etch rate. A comparison of the samples A and E (3.75 sccm CHF3 / 0.94 sccm Ar / 0.31 sccm O2) shows a reduction of the duty cycle from 0.36 (sample A) to 0.30 (sample E) with increasing acceleration voltage. The higher divergence of the incoming ions (Uacc = −1000 V) causes a higher side-wall removal and hence smaller duty cycles. For the samples D and F (4.06 sccm CHF3 / 0.94 sccm Ar) an increase of the 52 Figure 1: SEM measurements of the different gratings (A-F). Etching parameters are mentioned in the text. acceleration voltage leads to similar changes of the profile shape. In addition, a higher acceleration volt- age (samples E and F) causes almost binary profiles with side-wall angles of 0° compared to a lower ac- celeration voltage of −100 V (samples A, B, C, and D). The minimum duty cycle of 0.30 corresponds to a ridge width of 100 nm resulting in an aspect ratio of 7.9 (grating depth: 790 nm). Regarding the meas- ured diffraction efficiencies, the samples etched with −100 V acceleration voltage (samples A, B, C, and D) achieve higher values (91.2% to 94.9%) than the samples etched with −1000V acceleration voltage (samples E and F) (83.4% and 90.2%). The relatively low efficiencies of sample E and F result from the nearly binary profiles. In the case of a binary profile, the tolerancing of the optimal profile depth and duty cycle is very small. For higher side-wall angles, the tolerance window for duty-cycle and depth is larger and consequently samples A, B, C, and D reach higher efficiencies. Literature [1] H.T. Nguyen, B.W. Shore, S.J. Bryan, J.A. Britten, R.D: Boyd, M.D. Perry, Optics Letters 22(3) (1997) 142 [2] F. Koch, D. Lehr, O. Schönbrodt, T. Glaser, R. Fechner, F. Frost, Microelectric Engineering 191 (2018) 60 [3] A. Finzel, F. Koch, G. Dornberg, D. Lehr, F. Frost, T. Glaser, Optical Engineering 58(9) (2019) 092614 BCPfilmsfor“writ-ing”ofvertical alignedlamellas.3

SELECTED RESULTS MOLECULAR MECHANISMS ON SURFACES AND INTERFACES Improving Molecular Compounds of Solar Cells Based on Computational Screening H. Krautscheid, Universität Leipzig and Thomas Heine, TU Dresden, Germany S. Zahn in collaboration with Efficient n-type dye-sensitized solar cells are known since the seminal work of O’Reagan and Grätzel in 1991. However, highly efficient p-type dye-sensitized solar cells were not developed so far. This hinders the construction of tandem dye-sensitized solar cells which can surpass the performance of n-type de- vices. We have investigated if a temporary link be- tween a transition metal-based redox mediator and a sensitizer can increase the efficiency of p-type dye- sensitized solar cells [1]. This link should result in a close distance of counter charges after photoreduc- tion of the dye stabilizing the reduced dye (Fig. 1) and, thus, slow down charge recombination pro- cesses between sensitizer and semiconductor. Addi- tionally, the neighboured counter charges should ac- celerate the electron transfer from the dye to the re- dox mediator. If the transferred electron occupies an antibonding d-orbital of the transition metal complex, the link between redox mediator and the coordinated dye can be broken facilitating the regeneration of the dye. Complexes based on Co, Ni and Cu where selected for computational screening. In all cases a signifi- cantly weakened bond between the transition metal and the dye was observed after reduction. Further- more, the investigated Cu complexes showed the preferred push-pull MO structure where the highest occupied molecular orbital resides close to the sem- iconductor while the lowest unoccupied orbitals are located at the linked redox mediator. Unfortunately, a working device was obtained only for the Co com- Figure 1: Schematic illustration to highlight the advantages of temporary docking of the redox mediator (RM) at the sensi- tizer. a): Mode of action used so far. b): Investigated concept of temporary docking of the RM at the dye. Green illustrates uncharged components while blue/red illustrates regions of negative/positive charge. 54 Figure 2: Typical absorption spectra of Tetraphenylporphyrin showing the characteristic Soret and Q-bands. frameworks plexes. In case of the investigated Ni and Cu com- plexes, a reduction to immobile Ni(0) and Cu(0) could not be excluded additionally to an overall low stability of the transition metal complexes visible by the high air sensitivity of the synthesized Ni complexes. A quenching of the excited state could be observed for the Co complexes inhibiting a fast electron transfer from the dye to the redox mediator. Additionally, solar cells based on surface-mounted metal organic (SURMOF) were screened by computational approaches for which porphyrins are among the most promising molecular compounds [2]. However, Q-bands of porphyrins possess an overall low extinction coefficient, see Fig. 2. Computational screening showed that a modifica- tion of attached phenyl groups in meso position hardly affects light absorbing properties as long as strong nonplanar deformations are not induced by additional substituents. The latter as well as increas- ing or decreasing the conjugated π-system resulted in a red shift and an increased extinction coef- ficient of the modified porphyrins. Additional effects within the crystal structure were identified by com- putational screening in the Heine group. Literature [1] S. Merker, H. Krautscheid, S. Zahn, J. Mol. Model. 24 (2018) [2] R. Haldar, K. Batra, S.M. Marschner, A.B. Kuc, S. Zahn, R.A. Fischer, S. Bräse, T. Heine, C. Wöll, Chem. Eur. J. 25 (2019) 7847 317 MOLECULAR MECHANISMS ON SURFACES AND INTERFACESSELECTED RESULTS Near-Infrared Hyperspectral Imagingfor Monitoring the ThicknessDistribution of ThinPEDOT:PSS LayersPEDOT:PSS consisting of poly(3,4-ethylenedioxythi-ophene)(PEDOT) and polystyrene sulfonate(PSS) isa well-known conductive polymer with excellenttransparency, high conductivity and high chemical stability. Thismacromolecular polyelectrolyte com-plexforms stable aqueous suspensions, which can be applied by a wide range of processing methodssuch as spin coating, gravure printing, inkjetting,slot-die coating or with a doctor blade.The lattertechniques allow continuous roll-to-roll application toflexible substrates such as polymer films. Layersused as transparent electrode materialsshould be as thin and as homogeneousas possible. For aneffective control of the applied thickness, con-tinuous monitoring of the properties of the deposited layersisinevitable. White-light interferometry allowsmeasurementswith very high precision but isof lim-itedsuitability for space-resolved investigations, es-pecially iflarge areas have to be scanned. In thisstudy,NIR hyperspectral imaging was shownto bea powerful method for such investigations in spite of the very low thickness of conductive polymer layers(~50 to 350 nm). The predictionof quantitative thickness data from NIR reflectionspectra wasbased on chemometricmodels usingthe partial least squares(PLS)algo-rithm. Calibration wascarried out by meansof spin-coatedlayersof PEDOT:PSS, whose thickness wasdetermined by white-light interferometry and stylus profilometry. Finally, this resultedin calibration mod-elswithroot mean square errors of prediction (RMSEP) of less than 10 nm. These models wereused for quantitativeimaging of the thickness distri-bution inPEDOT:PSS layers on glass discs (Figure 1). Results reveal the typical inhomogeneities of spin-coated layerssuch as the hump in the centerand the ridge at the edge. The precisionof the pre-dicted values wasconfirmed by comparison withdata from various reference methods. Moreover, itwasshownthat thisapproach can be also used for hyperspectral imaging of the thickness of thin gravure printed layers and structures of PE-DOT:PSS on polymer films with excellent thickness resolution. Figure 2 showsthe hyperspectral imageof a test pattern printed on polyester film. It isobviousthat even the thinnest layers (right boxes in the lower line) as wellas labelscan be clearly detected by thismethod. Reproduction isonly limitedby the resolutionof the hyperspectral camera (2.6 mm/track). Thisanalytical approach opensnew possibilities for in-lineprocess control by large-scalemonitoring of thickness and homogeneity of ultrathin layersof con-ductive polymers and othersystems [1,2]. Literature[1]G. Mirschel, U.Helmstedt, T. Scherzer, U.Decker, L.Prager,Ind. Eng. Chem. Res.53 (2014)16813-16819[2]G. Mirschel, O. Daikos, T.Scherzer, Progr. Org. Coat. 132(2019) 116-1245

SELECTED REPORTS FUNCTIONAL SURFACES AND THIN FILMS Surface Modification of Gas Barrier Films for Direct and Dry Graphene Transfer – A Way to Transparent Flexible and Conductive Encapsulation Foils P. With, J. Lehnert, R. Heller, L. Prager, U. Helmstedt Wider adoption of flexible (organic) electronic de- vices e.g. in solar energy harvesting, smart packag- ing or displays, is limited by short device lifetimes due to degradation by atmospheric gases. Transpar- ent conductive encapsulation foils are therefore of high interest providing high flexibility, transparency, electrode stability and elasticity. Carbon-based elec- trode materials such as graphene and carbon nan- owires are promising materials for conductive thin films since they are highly flexible (bendable and stretchable), transparent, highly abundant and show excellent electrode stability. It is though challenging to adjust the surface and interface properties of the target substrate so that surface energy and rough- ness ensure sufficient electrode adhesion through- out subsequent processing steps. Furthermore, elec- trode deposition onto gas barrier films should be car- ried out in a dry processing step in order to prevent degradation of encapsulated sensitive electronic components by outgassing water. Several dry gra- phene transfer methods have been reported in the literature [1]. For most of them high temperatures (>80 °C) are necessary, which is not compatible with state of the art low-cost PET-based gas barrier films. Others involve an additional polymer substrate/ther- mal release tape for the final graphene transfer, in- creasing the number of processing steps. We pre- sent the direct and dry transfer of graphene grown on copper surfaces to gas barrier films at temperatures below 80 °C. Sufficient graphene adhesion on the target substrate has to be ensured for realization of a large-area transfer process [2], which requires adaptation of the surface energy and a compensation of roughness differences between the respective films. We have thus performed a systematic study in order to evalu- ate the impact of surface energy and glass transition temperature (Tg) for different types of coatings on SiOx/PET gas barrier films, the latter being prepared by a photochemical roll-to-roll process developed at IOM [3]. The study was performed with alkylsilaz- anes, alkylsiloxanes and acrylate systems with vary- ing side chains. In particular, soft acrylate-based coatings with low Tg showed high adhesion to gra- phene areas of several centimetres in size. Further advantages regarding processing of these acrylate- based coatings are their high chemical stability and 56 Figure 1: Photo of three overlapping graphene layers (G1, G2, G3) successively transferred to a gas barrier film (left), recovered copper foil after peeling off graphene; (left, inset) and UV/VIS transmittance at different positions of the overlapping graphene layers (right). that they can be photochemically cured at ambient conditions and on various organic and inorganic sub- strates (e.g. polyesters, glass). We were able to successfully carry out a simple and fast (<10 s) lamination process of graphene on pre- oxidized copper films [4] onto soft acrylate surface modified barrier films at temperatures of 20 to 60 °C (Fig. 1, left). The copper substrate could then simply be peeled off and is available for further graphene growth (Fig. 1, left, inset). A cost-intensive and wet chemical dissolution of copper can be omitted. The presence of graphene on barrier films was confirmed by RAMAN spectroscopy and the loss in transmission (at = 550 nm) corresponds to the theoretically ex- pected value of 2.4% per monolayer graphene (Fig. 1, right). With the method presented, not only larger pieces of graphene in the cm range can be transferred, but graphene layers can also be stacked on top of each other (patchwork approach), which increases area coverage and enables the introduction of dopants between individual graphene layers in order to pro- duce transparent and flexible high-performance elec- trodes [5]. Literature [1 J. Kang, D. Shin, S. Bae, B.H. Hong, Nanoscale 4 (2012) ] 5527 ] [2 Martins et al., PNAS 110 (2013) 17762 [3] L. Prager et al., Thin Solid Films 570 (2014) 87 [4] P.R. Whelan et al., Carbon 117 (2017) 75 [5] US 201801423

APPLICATION CENTER OF THE IOM MISSION The Application Center of the IOM is a technology platform for the efficient and sustainable transfer of IOM research results to industrial partners. Radiationbased high technologies, new process technolo- gies, and products can be developed at the IOM for industry under industry-relevant conditions. The aim is to transfer technological developments from pilot scale to scale up, especially in the fields of optical and chemical industry, semiconductor technology, mechanical engineering and medical technology. TASKS Provision of research and development services in the form of contract research Cooperative research together with users Pilot plants, sampling and small series production

PLASMA JET PROCESS FOR ULTRA-PRECISION SURFACE TREATMENT Plasma jet-based processing chains for the manufacturing of optical freeform surfaces of fused silica are comprised of several machining steps including plasma jet polishing. The main advantage of the plasma jet polishing process is its action independent of surface curvature. Hence, shape-preserving smoothing is achieved even on surfaces with variable surface curvatures like aspheres or freeforms. The new plasma jet polishing machine is based on a 4-axes CNC platform equipped with a specially designed microwave-driven inert plasma jet source. The machine allows to treat fused silica surfaces with lateral dimensions up to 250 mm in diameter obtaining micro-roughness values of less than 0.3 nm RMS. Expertise Plasma jet machining of surfaces Plasma assisted polishing of surfaces Ion beam figuring Reactive plasma jet sources –

PILOT-SCALE COATING MACHINE FOR FLEXIBLE GAS BARRIER FILMS IN ROLL-TO-ROLL PROCESS Development of cost-efficient flexible gas-barrier films for encapsulation of sensitive thin-film photovol- taics is currently a challenge facing industry when aiming on higher quota of renewable energy produc- tion. Recently, a photochemical process working at normal pressure and low temperature has been developed at IOM. The process involves UV-initiated conversion of a thin polysilazane layer into silica. A pilot-scale coating machine has been designed and constructed with the aim to further develop gas- barrier films and their production technology. The machine enables scale-up to wider substrates, demon- strations in true technical scale, and resilient economical evaluation of the production process. Expertise Low-temperature processes for preparation of metal oxide thin films Silicon oxide thin films for flexible transparent high gas permeation barrier Lamination of single laye films (up to 500 mm web width)

HERTZ ELECTRON BEAM LABORATORY MISSION The Hertz electron beam laboratory houses a 10 MeV electron accelerator for material modification as well as time-resolved basic investigations on the kinetics and dynamics of reactive processes. This enables the production of new materials for a wide variety of high-tech applications in close proximity to industry. This unique accelerator infrastructure is used for research and development in the field of material sciences, in joint projects with external university and non-university cooperation partners as well as industry. EQUIPMENT The accelerator at the IOM is based on a technological platform providing computer-controlled stable average beam currents up to 1 mA (10 kW beam power) for material modification. The high energy of linking (PE, Hydrogels, Cryogels …)

LASER LABORATORY MISSION Lasers are a versatile tool for materials processing that integrate well into production processes enabling a large variety of patterning, modification or deposition processes. The IOM laser machining (LAMA) group aims to the development of laser micro processing tech- niques for high quality, high precision and low damage laser processing of materials. The application-related research bases on the understanding of basic principles of laser material processes, the versatile control of the laser beam and the tuning of the laser machining processes to the particular needs of the application. Application-related work is performed in close cooperation with different industrial partners. Special attention is paid to: Texturing of plane and cylindrical surfaces Scribing of thin films for electronic devices, e.g. photovoltaics Machining of transparent materials for optical applications Surface functionalization for wetting, diffraction or mechanical applications The IOM’s Laser laboratories are equipped with standard industrial laser sources for materials pro-

FURTHER EQUIPMENT HIGH CURRENT ION IMPLANTER Ion implantation beyond doping concentration for adjustment of structural, mechanical, electronic or optical properties necessitates high ion currents which became only recently technically feasible. The low energy high current ion implanter provides ion energies between 5 and 200 keV with a beam current of up to 1 mA. A standard hot filament ion source allows the use of a variety of ions from gas- eous precursors while an additional evaporator en- larges the accessible range of elements which can be implanted using solid precursors. Mass separa- tion permits the direct implantation of the required ion species without contaminations. Using the avail- able cold and hot stages, ion implantation tempera- tures between – 150 and + 600 °C are possible. The accessible substrate size is up to 3 inch. SYSTEM FOR DETERMINISTIC SINGLE ION IMPLANTATION Deterministic ion implantation, i.e. the implantation of a pre-defined, counted number of single ions with a lateral accuracy of a few nanometers, is a promis- ing technique to realize a functionalization of single atoms in a solid state material. In the framework of a mutual project, the Leibniz Joint-Lab “Single Ion Implantation” of the IOM and the Applied Quantum Systems Department of Leipzig University was equipped with an advanced high resolution focused ion beam system containing a high precision laser interferometer stage for accurate and reproducible sample positioning. This development system has been equipped with an electron beam ion source and will be extended with a sophisticated single ion detector in order to fabricate quantum devices or sensors based on functionalized single atoms.

MATERIAL CHARACTERIZATION AND ANALYTICS MISSION The experimental infrastructure comprises a broad portfolio of instrumental methods to allow a compre- hensive physical and chemical characterization of materials. A main focus is set to surface-related an- alytical techniques. Therefor imaging methods show a huge versatility together with a high performance. Several additional techniques are available for the determination of the elemental and the chemical composition, the analysis of molecular, crystalline, and phase conditions as well as to characterize func- tional properties of materials. Expertise Surface analysis: microscopy, topography, wetting Material characterization: material composition, phase and thermal analysis Molecular structure: structure determination, substance separation, mass spectrometry Analysis of crystalline solids: crystalline structure, phase distribution, real structure Functional material properties: viscoelastic properties, thin film characterization

GRADUATIONS Habilitations 2019 Kahnt, Axel, Dr. Time resolved investigations on nanomaterials Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Naturwissenschaftliche Fakultät, 2019 Doctoral Theses 2018 Hilmi, Isom Epitaxial chalcogenide Ge-Sb-Te thin films and superlattices by pulsed laser deposition Universität Leipzig, Fakultät für Physik und Geowissenschaften, 2018 Hintzen, Daniel Erythrosin B als Sonde für Wasserstoffbrückenbindungen in verschiedenen molekularen Umgebungen Universität Leipzig, Fakultät für Chemie und Mineralogie, 2018 Lautenschläger, Thomas Systematic investigation of the ion beam sputter deposition of TiO2 Universität Leipzig, Fakultät für Physik und Geowissenschaften, 2018 Lohmann-Richters, Felix Fundamentals and applications of advanced solid acid fuel cell electrodes Universität Leipzig, Fakultät für Chemie und Mineralogie, 2018 2019 Bandak, Juhaina Amyloid fibril-based hybrid materials: characterization and application Universität Leipzig, Fakultät für Chemie und Mineralogie, 2019 Glaß, Sarah Characterization and application of hydrogels containing photoactive molecules Universität Leipzig, Fakultät für Chemie und Mineralogie, 2019 Grüner, Christoph Oblique angle deposition of thin films – theory, modelling, and application Universität Leipzig, Fakultät für Physik und Geowissenschaften, 2019 Laube, Christian Surface modification and electron irradiation treatment of nanodiamonds Universität Leipzig, Fakultät für Chemie und Mineralogie, 2019 Lehnert, Jan Synthesis of graphene using carbon ion implantation in copper Universität Leipzig, Fakultät für Physik und Geowissenschaften, 2019 Liedtke-Grüner, Susann Growth of obliquely deposited metallic thin films Universität Leipzig, Fakultät für Physik und Geowissenschaften, 2019 Niefind, Falk Nanoscale morphology of semiconducting polymer films by photoemission electron microscopy Universität Leipzig, Fakultät für Chemie und Mineralogie, 2019 76 BC

GRADUATIONS 2019 Abel, Tobias TEM investigation to optimize optical switching of epitaxial Ge2Sb2Te2 thin films Universität Leipzig, Fakultät für Physik und Geowissentschaften, 2019 Bernstein, Jacques Schichtabscheidung von SiO2-Dünnschichten mit reaktiven Ionenstrahlen Universität Leipzig, Fakultät für Physik und Geowissentschaften, 2019 Dietrich, Johannes Simulation of contact-resonance atomic force microscopy with the finite element method and comparison with experiments Universität Leipzig, Fakultät für Physik und Geowissentschaften, 2019 Fella, Johannes Entwurf und Inbetriebnahme einer Apparatur zur Synthese von Nanopartikeln durch Inertgaskondensation mittels Sputterquellen Universität Leipzig, Fakultät für Physik und Geowissentschaften, 2019 Herath, Sören TEM Charakterisierung von ionenstrahl-gestützt epitaktisch gewachsenen GaN-Dünnschichten Universität Leipzig, Fakultät für Physik und Geowissentschaften, 2019 Niavarani, Zahra Development of adsorber membranes with MIP modification for the removal of micropollutants from water Technische Universität Chemnitz, Fakultät für Naturwissenschaften, 2019 Schütte, Friedrich Electron beam modified collagen fibers - synthesis and characterization of global and local mechanical response Universität Leipzig, Fakultät für Physik und Geowissentschaften, 2019 Tietz, Matthias Untersuchung des Temperatureinflusses auf die photochemisch initiierte Umsetzung von Tetraisobutylorthotitanat Universität Leipzig, Fakultät für Chemie und Mineralogie, 2019 Wang, Rui Untersuchung zum lateralen Alignment der Werkzeugfunktion beim Plasma Jet Machining TU Dresden, Fakultät Maschinenwesen, 2019 Wu, Junfang Untersuchungen zur plasmagestützten Schichtabscheidung dünner Schichten an Atmosphärendruck zur Formkorrektur optischer Oberflächen TU Dresden, Fakultät Maschinenwesen, 2019 78 Chair, The Journals’ Editor Conference, AIP Publishing, New York, USAMember, Coordinating Committee, Society “Plasma Germany”C „Physikalische Chemie“ cted member of the DFG review panel „Physikalische und Theoretische Chemie“ of the –Fachausschuss „Oberflächen für die Biound Medizintechnik“Advisory Board „Nanotechnology“ IOP Sciencecommittee „EOS Conferences at the World of Photonics Congress ): Conference on Manufacturing of Optical Systems“

COMMITTEE WORK John, Torsten Board Member of the International Younger Chemists Network (IYCN) Selection Committee Member for the Historical Landmarks Award of the European Chemical Society (EuChemS) Board Member (Secretary) of the European Young Chemists’ Network (EYCN) Knolle, Wofgang, Dr. Member of the Editorial Board “Radiation Physics and Chemistry” Lotnyk, Andriy, Dr. Second speaker of the working group High-Resolution Transmission Electron Microscopy (German Society for Electron Microscopy) Mändl, Stephan, Dr. Member of the International Committee “Plasma Based Ion Implantation and Deposition“ Guest Editor Surf. Coat. Technol. Proc. 14th International Conference on Plasma-Based Ion Implantation and Deposition Guest Editor Surf. Coat. Technol. Proc. 15th International Conference on Plasma-Based Ion Implantation and Deposition Mayr, Stefan, Prof. Dr. Scientific Board at the Leibniz MMS Days 2018 Reviewer in the Review Board of the DFG Monakhov, Kirill, Dr. Member of the International Research Network IRN-POM Smart Molecular Oxides Member of the German Chemical Society (GDCh) Guest Editor on the research topic "Nanoscale Imaging of Coordination Compounds and Their Assemblies" in Frontiers in Chemistry Scherzer, Tom, Dr. Advisory Board of the European European Symposium of Photopolymer Science Advisory Board of the International Symposium on Photopolymerization Zimmer, Klaus, Dr. Member of the Editorial Board “Surfaces and Interfaces” Elsevier 80 –"

SCIENTIFIC EVENTS Scientific Meetings co-organized by IOM 3rd Leibniz MMS Days “Mathematical Modeling and Simulation” 28.02.-02.03.2018, Leibniz Institute of Surface Engineering (IOM), Leipzig, Germany XXV. Erfahrungsaustausch Oberflächentechnologie mit Plasma- und Ionenstrahlprozessen 20.-23.03.2018, Mühlleithen, Germany 4nd International Summer School “Trends in Ultra-precision optical surface engineering Manufacturing methods and applications” 03.-07.09.2018, Leibniz Institute of Surface Engineering (IOM), Leipzig, Germany 7th Russian-German Conference “Electric Propulsions - New Challenges” 21.-26.10.2018, Gießen, Germany XXVI. Erfahrungsaustausch Oberflächentechnologie mit Plasma- und Ionenstrahlprozessen 05.-07.03.2019, Mühlleithen, Germany GRAVOMER – Kompetenzregion mikrostrukturierte Funktionsoberflächen (Alliance kick-off meeting) 18.09.2019, Leibniz Institute of Surface Engineering (IOM), Leipzig, Germany Vom Labor in die Praxis – mit Innovationen Unternehmen stärken: „Oberflächen nach Maß - Mikrostrukturierte Funktionsoberflächen“ 12.11.2019, Leibniz Institute of Surface Engineering (IOM), Leipzig, Germany International Conference on Laser Interaction with Material and Applied Laser 2019 (LIMA) 27.-29.11.2019, Shanghai, China Institute Colloquia Prof. Dr. Thomas Höche (12.12.2019) Fraunhofer Institute for Microstructure of Materials and Systems IMWS Halle, Germany Mikrostrukturbasierte Material- und Prozessentwicklung Prof. Dr. Koen Vandewal (05.12.2019) Instituut voor Materiaalonderzoek, Diepenbeek, Belgium Fundamentals and applications of intermolecular charge-transfer states Prof. Ferdinand Schmidt-Kaler (17.10.2019) Johannes Gutenberg-Universität Mainz, Institut für Physik, Germany Trapped ion quantum computing and single ion implantation for novel quantum technologies Prof. Dr. M. Sommer (11.07.2019) TU Chemnitz, Germany N-type copolymers for organic photovoltaics, field-effect transistors and thermoelectrics PD Dr. habil. Yogendra K. Mishra (27.06.2019) Kiel University, Institute for Materials Science, Germany Flame based ZnO tetrapod nanomaterials for multifunctional applications Dr. Sven Schröder (20.06.2019) Fraunhofer Institute Applied Optics and Precision Engineering IOF, Jena, Germany Rauheit und Streulicht ultrapräziser optischer Oberflächen und Schichten Prof. Dr. F. Jelezko (13.06.2019) Ulm University, Germany Quantum sensing enabled by color centres 84 T,C

SCIENTIFIC EVENTS Dr. Kerstin Thorwarth (05.07.2018) Laboratory for Nanoscale Materials Science Empa Swiss Federal Laboratories for Materials Science and Technology, Switzerland Smarter implants by PVD: Needs and challenges Dr. Klaus Mann (28.06.2018) Laser Laboratorium Göttingen e. V. (LLG), Germany Vom tiefen UV in den Röntgenbereich: Überblick über die Arbeiten der Abteilung Optik/ Kurze Wellenlängen des LLG Prof. Dr. Manfred Albrecht (21.06.2018) Universität Augsburg, Institut für Physik, Germany Ferrimagnetic Tb-Fe based heterostructures: Intriguing properties and applications Prof. Dr. Jochen Balbach (14.06.2018) Martin-Luther-Universität Halle-Wittenberg, Germany High-resolution NMR-spectroscopy of biomolecules: From formation of structures to structural and dynamic interaction Dr. Jean Dijon (31.05.2018) CEA-LITEN, Grenoble, France Platinum as a material of choice to grow and dope single layer graphene Frank Siewert (24.05.2018) Helmholtz Zentrum Berlin, Germany On the current state of ultra-precise optical elements for Synchrotron- and FEL-application Prof. Dr. Thomas Heine (17.05.2018) Leipzig University, Wilhelm-Ostwald-Institut, Germany Computational theoretical chemistry: Understanding and predicting novel 2D-materials Dr. Timothy E.L. Douglas (26.04.2018) Lancaster University, UK Mineralised hydrogels for bone regeneration Prof. Dr. Oliver Kühn (19.04.2018) University of Rostock, Germany First principles approach to the x-ray spectroscopy of transition metal complexes Prof. Dr. Bernd Herzog (01.02.2018) BASF Ludwigshafen, Germany Recent developments in the photoprotection of human skin - UV-absorbers, nanoparticles and thin films Dr.-Ing. Anke Dalke (25.01.2018) TU Bergakademie Freiberg, Germany Plasmanitrieren - Stand der Technik und neue Möglichkeiten Prof. Jochen M. Schneider (18.01.2018) RWTH Aachen University, Germany Quantum mechanically guided materials design for surface engineering Prof. Dr. Jan Münch (11.01.2018) University Ulm, Germany Simulation of light-induced processes: Molecular materials and proteins 86 “

SCIENTIFIC EVENTS Spemann, Daniel, Dr. Kernphysik Universität Leipzig, Fakultät für Physik und Geowissenschaften Summer 2018, Summer 2019 Experimentalphysik VII – Kern- und Teilchenphysik Universität Leipzig, Fakultät für Physik und Geowissenschaften Winter 2018/19, Winter 2019/20 With, Patrick, Dr. Modul "Photochemische Methoden" in "Funktionskontrolle an komplexen Oberflächen“ Universität Leipzig, Fakultät für Chemie und Mineralogie Winter 2019/20 Zahn, Stefan, Dr. Postgraduales Aufbaustudium "Analytik & Spektroskopie" Universität Leipzig, Fakultät für Chemie und Mineralogie Winter 2018/19 Seminar Series Anders, André, Prof. Dr. Plasmas Physics, Thin Film Deposition and Characterization Universität Leipzig, Fakultät für Physik und Geowissenschaften Winter 2019/20 Helmstedt, Ulrike, Dr. Modul "Dünne Schichten" in "Funktionskontrolle an komplexen Oberflächen“ Universität Leipzig, Fakultät für Chemie und Mineralogie Winter 2019/20 Mändl, Stephan, Dr. Plasmas Physics, Thin Film Deposition and Characterization Universität Leipzig, Fakultät für Physik und Geowissenschaften Winter 2019/20 Mayr, Stefan G., Prof. Dr. Seminar „Oberflächenphysik“ Universität Leipzig, Fakultät für Physik und Geowissenschaften Winter 2017/18, Summer 2018, Winter 2018/19, Summer 2019, Winter 2019/20 Hauptseminar – “Modern Developments in Solid State Physics” Universität Leipzig, Fakultät für Physik und Geowissenschaften Winter 2017/18, Winter 2018/19, Winter 2019/20 Seminar zu Experimentalphysik 5 - Festkörperphysik Universität Leipzig, Fakultät für Physik und Geowissenschaften Winter 2017/18, Winter 2018/19, Winter 2019/20 Riedel, Stefanie, Dr. Hauptseminar – “Modern Developments in Solid State Physics” Universität Leipzig, Fakultät für Physik und Geowissenschaften Winter 2019/20 88 –Modul "Photochemische Methoden" in "Funktionskontrolle an komplexen Oberflächen“

PUBLICATIONS IN JOURNALS AND BOOKS Publications in Journals and Books 2018 A. Anders, Y. Yang Plasma studies of a linear magnetron operating in the range from DC to HiPIMS J. Appl. Phys. 123 (2018) 043302 J. Appun, F. Stolz, S. Naumov, B. Abel, C. Schneider The rapid, modular, and highly efficient synthesis of dipyrroloquinolines: A combined cxperimental and analytical study J. Org. Chem. 83 (2018) 1737-1744 P.A. Atanasov, N.N. Nedyalkov, R.G. Nikov, C. Grüner, B. Rauschenbach, N. Fukata SERS analysis of Ag nanostructures produced by ion-beam deposition J. Phys.: Conf. Ser. 992 (2018) 012050 P.A. Atanasov, N.N. Nedyalkov, Ru.G. Nikov, N. Fukuta, W. Jevasuwan, T. Subramani, D. Hirsch, B. Rauschenbach SERS analyses of thiamethoxam assisted by Ag films and nanostructures produced by laser techniques J. Raman Spectrosc. 49 (2018) 397-403 T. Bahners, B. Gebert, A. Prager, N. Hartmann, U. Hagemann, J.S. Gutmann UV-light assisted patterned metallization of textile fabrics Appl. Surf. Sci. 436 (2018) 1093-1103 P. Bassereau, R. Jin, T. Baumgart, M. Deserno, V.A. Frolov, P.V. Bashkirov, H. Grubmüller, R. Jahn, H.J. Risselada, L. Johannes, M.M. Kozlov, R. Lipowsky, T.J. Pucadyil, W.F. Zeno, J.C. Stachowiak, D. Stamou, A. Breuer, L. Lauritsen, et al. The 2018 biomembrane curvature and remodeling roadmap J. Phys. D: Appl. Phys. 51 (2018) 343001 J. Bauer, M. Ulitschka, F. Pietag, T. Arnold Improved ion beam tools for ultraprecision figure correction of curved aluminum mirror surfaces J. Astron. Telesc. Instrum. Syst. 4 (2018) 046003 M. Behrens, A. Lotnyk, J.W. Gerlach, I. Hilmi, T. Abel, P. Lorenz, B. Rauschenbach Ultrafast interfacial transformation from 2D- to 3D-bonded structures in layered Ge-Sb-Te thin films and heterostructures Nanoscale 10 (2018) 22946-22953 M. Behrens, A. Lotnyk, U. Roß, J. Griebel, P. Schumacher, J.W. Gerlach, B. Rauschenbach Impact of disorder on optical reflectivity contrast of epitaxial Ge2Sb2Te5 thin films CrystEngComm 20 (2018) 3688-3695 C. Bundesmann, H. Neumann Tutorial: The systematics of ion beam sputtering for deposition of thin films with tailored properties J. Appl. Phys. 124 (2018) 231102 M.V. Cakir, U. Allenstein, M. Zink, S.G. Mayr Early adhesion of cells to ferromagnetic shape memory alloys functionalized with plasma assembled biomolecules - a single cell force spectroscopy study Mater. Des. 158 (2018) 19-27 R. Chanson, L. Zhang, S. Naumov, Yu.A. Mankelevich, T. Tillocher, P. Lefaucheux, R. Dussart, S. De Gendt, J-F. de Marneffe Damage-free plasma etching of porous organo-silicate low-k using micro-capillary condensation above -50 oC Sci. Rep. 8 (2018) 1886 92

PUBLICATIONS IN JOURNALS AND BOOKS F. Haase, D. Manova, D. Hirsch, S. Mändl, H. Kersten Dynamic determination of secondary electron emission using a calorimetric probe in a plasma immersion ion implantation experiment Plasma Sources Sci. Technol. 27 (2018) 044003 T. Herzig, P. Räcke, N. Raatz, D. Spemann, W. Redjem, J.W. Gerlach, J. Meijer, G. Cassabois, M. Abbarchi, S.Pezzagna Creation of quantum centers in silicon using spatial selective ion implantation of high lateral resolution Proc. 22nd Int. Conf. on Ion Implantation Technology (2018) 136-139 E. Jahangiri, I. Thomas, A. Schulze, B. Seiwert, H. Cabana, D. Schlosser Characterisation of electron beam irradiation-immobilised laccase for application in wastewater treatment Sci. Total Environ. 624 (2018) 309-322 T. John, A. Gladytz, C. Kubeil, L.L. Martin, H.J. Risselada, B. Abel Impact of nanoparticles on amyloid peptide and protein aggregation: A review with a focus on gold nanoparticles Nanoscale 10 (2018) 20894-20913 T. John, B. Abel, L.L. Martin The quartz crystal microbalance with dissipation monitoring (QCM-D) technique applied to the study of membrane-active peptides Aust. J. Chem. 71 (2018) 543-546 F. Koch, D. Lehr, O. Schönbrodt, T. Glaser, R. Fechner, F. Frost Manufacturing of highly-dispersive, high-efficiency transmission gratings by laser interference lithography and dry etching Microelectron. Eng. 191 (2018) 60-65 C. Laube, J. Hellweg, C. Sturm, J. Griebel, M. Grundmann, A. Kahnt, B. Abel Photoinduced heating of graphitized nanodiamonds monitored by the Raman diamond peak J. Phys. Chem. C 122 (2018) 25685-25691 J. Lehnert, D. Spemann, S. Surjuse, M. Mensing, C. Grüner, P. With, P. Schumacher, A. Finzel, D. Hirsch, B. Rauschenbach Preparation and characterisation of carbon-free Cu(111) films on sapphire for graphene synthesis J. Phys.: Conf. Ser. 992 (2018) 012024 S. Liedtke, C. Grüner, J.-W. Gerlach, A. Lotnyk, B. Rauschenbach Crystalline Ti-nanostructures prepared by oblique angle deposition at room temperature J. Vac. Sci. Technol. B 36 (2018) 031804 S. Liedtke, Ch. Grüner, J.W. Gerlach, B. Rauschenbach Comparative study of sculptured metallic thin films deposited by oblique angle deposition at different temperatures Beilstein J. Nanotechnol. 9 (2018) 954-962 O. Link, E. Lugovoy, B. Abel Interface solvated electrons Encyclopedia of Interfacial Chemistry - Surf. Sci. Electrochem. (2018) 433-442 O. Linnenberg, M. Moors, A. Notario-Estévez, X. López, C. de Graaf, S. Peter, C. Bäumer, R. Waser, K. Yu. Monakhov Adressing multiple resistive states of polyoxovanadates: Conductivity as a function of individual redox states. J. Am. Chem. Soc. 140 (2018) 16635-16640 Y. Liu, D. Hirsch, R. Fechner, Y. Hong, S. Fu, F. Frost, B. Rauschenbach Nanostructures on fused silica surfaces produced by ion beam sputtering with Al co-deposition Appl. Phys. A 124 (2018) 73 94

PUBLICATIONS IN JOURNALS AND BOOKS M. Mitterbauer, P. Knaack, S. Naumov, M. Markovic, A. Ovsianikov, N. Moszner, R. Liska Acylstannanes - a new generation of cleavable and highly reactive photoinitiators for curing at wavelengths above 500 nm with excellent photobleaching behavior Angew. Chemie Int. Ed. 57 (2018) 12146-12150 A. Müller, A. Preuß, T. Bornhütter, I. Thomas, A. Prager, A. Schulze, B. Röder Electron beam functionalized photodynamic polyether-sulfone membranes photophysical characterization and antimicrobial activity Photochem. Photobiol. Sci. 17 (2018) 1346-1354 O. Naumov, S. Naumov, B. Abel, A. Varga The stability limits of highly active nitrogen doped carbon ORR nano-catalysts: a mechanistic study of degradation reactions Nanoscale 10 (2018) 6724-6733 V. Nikolaou, F. Plass, A. Planchat, A. Charisiadis, G. Charalambidis, P.-A. Angaridis, A. Kahnt, F. Odobel, A.-G. Coutsolelos Effect of the triazole ring in zinc porphyrin-fullerene dyads on the charge transfer processes in NiO- based devices Phys. Chem. Chem. Phys. 20 (2018) 24477-24489 J.-C. Oliveira, F. Ferreira, A. Anders, A. Cavaleiro Reduced atomic shadowing in HiPIMS: Role of the thermalized metal ions Appl. Surf. Sci. 433 (2018) 934-944 L. Pietzonka, T. Lautenschläger, D. Spemann, A. Finzel, J.W. Gerlach, F. Frost, C. Bundesmann Ion beam sputter deposition of TiO2 films using oxygen ions Eur. Phys. J. B 91 (2018) 252 F. Postberg, N. Khawaja, B. Abel, G. Choblet, C.R. Glein, M.S. Gudipati, B.L. Henderson, H.-W. Hsu, S. Kempf, F. Klenner, G. Moragas-Klostermeyer, B. Magee, L. Nölle, M. Perry, R. Reviol, J. Schmidt, F. Stolz, G. Tobie, M. Trieloff, J.H. Waite Macromolecular organic compounds from the depths of Enceladus Nature 558 (2018) 564-568 P. Räcke, D. Spemann, J.W. Gerlach, B. Rauschenbach, J. Meijer Detection of small bunches of ions using image charges Sci. Rep. 8 (2018) 9781 A. Reinhardt, I. Thomas, J. Schmauck, R. Giernoth, A. Schulze, I. Neundorf Electron beam immobilization of novel antimicrobial, short peptide motifs leads to membrane surfaces with promising antibacterial properties J. Funct. Biomater. 9 (2018) 21 E. Reisz, C. von Sonntag, A. Tekle-Röttering, S. Naumov, W. Schmidt, T. Schmidt Reaction of 2-propanol with ozone in aqueous media Water Research 128 (2018) 171-182 C. Richter, D. Hollas, C.-M. Saak, M. Förstel, T. Miteva, M. Mucke, O. Björneholm, N. Sisourat, P. Slavicek, U. Hergenhahn Competition between proton transfer and intermolecular Coulombic decay in water Nat. Comm. 9 (2018) 4988 S. Riedel, K. Bela, E.I. Wisotzki, C. Suckfüll, J. Zajadacz, S.G. Mayr Reagent-free mechanical patterning of gelatin surfaces by two-step electron irradiation treatment Mater. Des. 153 (2018) 80-85 S. Riedel, S.G. Mayr Reagent-free programming of shape-memory behavior in gelatin by electron beams: Experiments and modeling Phys. Rev. Appl. 9 (2018) 024011 96 π

PUBLICATIONS IN JOURNALS AND BOOKS S. Zöhrer, A. Anders, R. Franz Influence of Ar gas pressure on ion energy and charge state distributions in pulsed cathodic arc plasmas from NbAl cathodes studied with high time resolution J. Phys. D: Appl. Phys. 52 (2018) 055201 2019 P. Ahrens, M. Zander, D. Hirsch, U. Hasse, H. Wulff, F. Frost, F. Scholz Influence of argon ion beam etching and thermal treatment on polycrystalline and single crystal gold electrodes Au(100) and Au(111) J. Electroanal. Chem. 832 (2019) 233-240 R.K. Al-Shewiki, M. Korb, A. Hildebrandt, S. Zahn, S. Naumov, R. Buschbeck, T. Rüffer, H. Lang Diaqua-β-octaferrocenyltetraphenylporphyrin: a multiredox-active and air-stable 16π non-aromatic species Dalton Trans. 48 (2019) 1578-1585 B.S. Basel, C. Hetzer, J. Zirzlmeier, D. Thiel, R. Guldi, F. Hampel, A. Kahnt, T. Clark, D.M. Guldi, R.R. Tykwinski Davydov splitting and singlet fission in excitonically coupled pentacene dimers Chem. Sci. 10 (2019) 3854-3863 F. Bauer, R. Meyer, S. Czihal, M. Bertmer, U. Decker, S. Naumov, H. Uhlig, M. Steinhart, D. Enke Functionalization of mesoporous siliceous materials, Part 2: Surface characterization by inverse gas chromatography J. Chrom. A 1603 (2019) 297-310 J. Bauer, F. Frost, A. Lehmann, M. Ulitschka, Y. Li, T. Arnold Finishing of metal optics by ion beam technologies Opt. Eng. 58 (2019) 092612 M. Behrens, A. Lotnyk, J.W. Gerlach, M. Ehrhardt, P. Lorenz, B. Rauschenbach Direct measurement of crystal growth velocity in epitaxial phase-change material thin films ACS Appl. Mater. Interfaces 11 (2019) 41544-41550 M. Berndt-Paetz, P. Schulze, P.C. Stenglein, A. Weimann, Q. Wang, L.-C. Horn, Y.M. Riad, J. Griebel, R. Hermann, A. Glasow, J.-U. Stolzenberg, J. Neuhaus Reduction of muscle-invasive tumors by photodynamic therapy with tetrahydroporphyrin-tetratosylat in an orthotopic rat bladder cancer model Mol. Cancer Ther. 18 (2019) 743-750 P. Bielytskyi, D. Gräsing, S. Zahn, K.D. Mote, A. Alia, P.K. Madhu, J. Matysik Assignment of NMR resonances of protons covalently bound to photochemically active cofactors in photosynthetic reaction centers by 13C-1H photo-CIDNP MAS-J-HMQC experiment J. Magn. Reson. 298 (2019) 64-76 P. Bielytskyi, D. Gräsing, S. Zahn, A. Alia, J. Matysik 15N-1H transfer of light-induced nuclear hyperpolarization in frozen photosynthetic reaction centers Appl. Magn. Reson. 50 (2019) 695-708 L. Botsch, I. Lorite, Y. Kumar, P.D. Esquinazi, J. Zajadacz, K. Zimmer All-semiconducting spin filter prepared by low-energy proton irradiation ACS Appl. Electron. Mater. 1 (2019) 1832-1841 D. Breite, M. Went, A. Prager, M. Kühnert, A. Schulze Charge separating microfiltration membrane with pH-dependent selectivity Polymers 11 (2019) 3 C. Bundesmann, T. Amelal Secondary particle properties for the ion beam sputtering of TiO2 in a reactive oxygen atmosphere Appl. Surf. Sci. 485 (2019) 391-401 98 D.Gräsing, K.M. Dziubińska

PUBLICATIONS IN JOURNALS AND BOOKS I. Hilmi, A. Lotnyk, J.W. Gerlach, P. Schumacher, B. Rauschenbach Influence of substrate dimensionality on the growth mode of epitaxial 3D-bonded GeTe thin films: From 3D to 2D growth Mater. Des. 168 (2019) 107657 A. Holm, S.G. Mayr Thermal and structural properties of the martensitic transformations in Fe7Pd3 shape memory alloys: An ab initio-based molecular dynamics study New J. Phys. 21 (2019) 063007 B. Holzer, M. Lunzer, A. Rosspeintner, G. Licari, M. Tromayer, S. Naumov, D. Lumpi, E. Horkel, C. Hametner, A. Ovsianikov, R.Liska, E. Vauthey, J. Fröhlich Towards efficient initiators for two-photon induced polymerization: Fine tuning of the donor/acceptor properties Mol. Syst. Des. Eng. 4 (2019) 437-448 L. Jablonowski, T. Kocher, A. Schindler, K. Müller, F. Dombrowski, T. von Woedtke, T. Arnold, A. Lehmann, S. Rupf, M. Evert, K. Evert Side effects by oral application of atmospheric pressure plasma on the mucosa in mice PLoS ONE 14 (2019) e0215099 T. John, G.W. Greene, N.A. Patil, T.J.A. Dealey, M.A. Hossain, B. Abel, L.L. Martin Adsorption of amyloidogenic peptides to functionalized surfaces is biased by charge and hydrophilicity Langmuir 35 (2019) 14522-14531 T. John, T.J.A. Dealey, N.P. Gray, N.A. Patil, M.A. Hossain, B. Abel, J.A. Carver, Y. Hong, L.L. Martin The Kinetics of amyloid fibrillar aggregation of uperin 3.5 is directed by the peptide's secondary structure Biochemistry 58 (2019) 3656-3668 D. Kalanov, A. Anders, C. Bundesmann Ion beam sputtering of silicon: Energy distributions of sputtered and scattered ions J. Vac. Sci. Technol. A 37 (2019) 051507 F. Kazemi, G. Böhm, T. Arnold Development of a model for ultra-precise surface machining of N-BK7® using microwave-driven reactive plasma jet machining Plasma Process Polym. 16 (2019) 1900119 K.S. Kisel, A.S. Melnikov, E.V. Grachova, A.J. Karttunen, A. Doménech-Carbó, K.Y. Monakhov, V.G. Semenov, S.P. Tunik, I.O. Koshevoy Supramolecular construction of cyanide-bridged ReI diimine multichromophores Inorg. Chem. 58 (2019) 1988-2000 J. Klose, T. Severin, P. Hahn, A. Jeremies, J. Bergmann, D. Fuhrmann, J. Griebel, B. Abel, B. Kersting Coordination chemistry and photoswitching of dinuclear macrocyclic cadmium-, nickel-, and zinc complexes containing azobenzene carboxylato co-ligands Beilstein J. Org. Chem. 15 (2019) 840-851 J. Kolbeck, A. Anders, I. Beilis, M. Keidar Micro-propulsion based on vacuum arcs J. Appl. Phys. 125 (2019) 220902 I. Lacey, R.D. Geckler, A. Just, F. Siewert, Th. Arnold, H. Paetzelt, B.V. Smith, V.V. Yashchuk Optimization of the size and shape of the scanning aperture in autocollimator-based deflectometric profilometers Rev. Sci. Instrum. 90 (2019) 021717 S. Lai, P. Lorenz, M. Ehrhardt, B. Han, D. Hirsch, I. Zagoranskiy, J. Lu, K. Zimmer Laser-induced frontside etching of silicon using 1550-nm nanosecond laser pulses Opt. Lasers Eng. 122 (2019) 245-253 100

PUBLICATIONS IN JOURNALS AND BOOKS G. Mirschel, O. Daikos, T. Scherzer In-line monitoring of the thickness distribution of adhesive layers in black textile laminates by hyperspectral imaging Comput. Chem. Eng. 124 (2019) 317-325 F. Niefind, A. Neff, S.C.B. Mannsfeld, A. Kahnt, B. Abel Computational analysis of the orientation persistence length of the polymer chain orientation Phys. Chem. Chem. Phys. 21 (2019) 21464-21472 F. Niefind, S. Karande, F. Frost, B. Abel, A. Kahnt Solvent influence on the surface morphology of P3HT thin films revealed by photoemission electron microscopy Nanoscale Adv. 1 (2019) 3883-3886 R. Pütt, X. Qiu, P. Kozłowski, H. Gildenast, O. Linnenberg, S. Zahn, R.C. Chiechi, K.Y. Monakhov Self-assembled monolayers of polyoxovanadates with phthalocyaninato lanthanide moieties on gold surfaces Chem. Commun. 55 (2019) 13554-13557 P. Räcke, R. Staacke, J.W. Gerlach, J. Meijer, D. Spemann Image charge detection statistics relevant for deterministic ion implantation J. Phys. D: Appl. Phys. 52 (2019) 305103 E. Reisz, A. Tekle-Röttering, S. Naumov, W. Schmidt, T.C. Schmidt Reaction of 1-propanol with ozone in aqueous media Int. J. Mol. Sci. 20 (2019) 4165 S. Riedel, P. Hietschold, C. Krömmelbein, T. Kunschmann, R. Konieczny, W. Knolle, C.T. Mierke, M. Zink, S.G. Mayr Design of biomimetic collagen matrices by reagent-free electron beam induced crosslinking: Structure-property relationships and cellular response Mater. Des. 168 (2019) 107606 S. Schmitz, X. Qiu, M. Glöß, J. van Leusen, N.V. Izarova, M.A. Nadeem, J. Griebel, R.C. Chiechi, P. Kögerler, K.Y. Monakhov Conductive self-assembled monolayers of paramagnetic {CoIICoIII clusters on Gold surfaces Front. Chem. 7 (2019) 681 4} and {CoII 4CoIII 2} coordination S. Schmitz, N.V. Izarova, C. Besson, J. van Leusen, P. Kögerler, K.Y. Monakhov Ion-directed coordinative polymerization of copper(II) pyridyl-alcohol complexes through thiane functionalities Z. Anorg. Allg. Chem. 645 (2019) 409-415 D.S. Seregin, S. Naumov, W.-Y. Chang, Y.-H. Wu, Y. Wang, N.M. Kotova, A.S. Vishnevskiy, S. Wei, J. Zhang, K.A. Vorotilov, M. Redzheb, J. Leu, M.R. Baklanov Effect of the C-bridge on UV properties of organosilicate films Thin Solid Films 685 (2019) 329-334 A. Solé-Daura, A. Notario-Estévez, J.J. Carbó, J.M. Poblet, C. de Graaf, K.Y. Monakhov, X. López How does the redox state of polyoxovanadates influence the collective behavior in solution? A case study with [I@V18O42]q- (q = 3, 5, 7, 11 and 13) Inorg. Chem. 58 (2019) 3881-3894 F. Strieth-Kalthoff, C. Henkel, M. Teders, A. Kahnt, W. Knolle, A. Gómez-Suárez, K. Dirian, W. Alex, K. Bergander, C. G. Daniliuc, B. Abel, D.M. Guldi, F. Glorius Discovery of unforeseen energy-transfer-based transformations using a combined screening approach Chem 5 (2019) 2183-2194 M. Stuckart, K.Y. Monakhov Polyoxometalates as components of supramolecular assemblies Chem. Sci. 10 (2019) 4364-4376 102

CONFERENCE PROCEEDINGS Conference Proceedings 2018 Th. Arnold, J.-B. Abadie, G. Böhm Surface figure error correction by additive plasma jet machining and ion beam assisted mask transfer Paper Nr. O1.02, Proc. EUSPEN 18th Int. Conf. & Exhibition, Venice, Italy, 04.-08.06. (2018) 47 T. Arnold, F. Frost, M. Nestler, A. Schindler, M. Zeuner Ultra-precision ion beam and plasma jet processing for advanced optics manufacturing Proc. Int. Symposium on Extreme Optical Manufacturing and Laser-Induced Damage in Optics, Chengdu, China, 26.-28.09. (2018) J. Bauer, M. Ulitschka, F. Frost, T. Arnold, L. Alber, M. Sondermann, G. Leuchs Ultra-precision surface figuring of optical aluminium devices Paper Nr. NoM3D.3, Proc. OSA Advanced Photonics 2018, Novel Optical Materials and Applications, Zurich, Switzerland, 02.-05.07. (2018) J. Bauer, M. Ulitschka, F. Pietag, T. Arnold Improved ion beam tools for ultra-precision figure correction of curved aluminium mirror surfaces Paper Nr. 10692-21, SPIE Optical Systems Design, Proc. Vol. 10692, Optical Fabrication, Testing, and Metrology VI, Frankfurt/Main, Germany, 14.-17.05. (2018) 106920M D. Breite, A. Prager, A. Schulze Charge selective polymer membranes with pH dependent selectivity Paper Nr. 269, Euromembrane 2018, Valencia, Spain, 09.-13.07. (2018) 211-212 D. Breite, R. Schiewe, M. Went, A. Prager, A. Schulze Surface hydrophilization of a microfiltration membrane using polyamide Paper Nr. P1.10, 17th Aachener Membran Kolloquium, Aachen, Germany, 14.-15.11. (2018) 227-231 M.A. Cisternas, M. Jose Retamal, P. Saikia, N. Casanova, N. Moraga, A. Chandia, A. Alvarez, D.E. Diaz- Droguett, F. Guzman, S. Mändl, D. Manova, T.P. Corrales, U.G. Volkmann, M. Favre, H. Bhuyan Study of phospholipid bilayers supported on Chitosan-Titanium Nitride coatings produced by plasma immersion ion implantation (PIII) Biophys. J. 114 (2018) 105a K. Fischer, A. Gawel, D. Rosen, M. Krause, A. Abdul Latif, J. Henke, I. Thomas, M. Kühnert, J. Griebel, A. Prager, A. Schulze Easy dip-coating method to covalently immobilize highly photocatalytic active TiO2 nanoparticles on a PES membrane Paper Nr. 340, Euromembrane 2018, Valencia, Spain, 09.-13.07. (2018) 243 A. Lotnyk, M. Behrens, I. Hilmi, B. Rauschenbach Epitaxial GeSbTe-based thin films and heterostructures: growth, microstructure and optical properties European Phase Change and Ovonic Symposium, Catania, Italy, 23.-25.09. (2018) 54-59 M. Schmidt, D. Breite, M. Went, A. Prager, A. Schulze Self-cleaning polymer membranes by chemical conjugation of digestive enzymes Paper Nr. OC35, EUPOC 2018, Como, Italy, 20.-24.05. (2018) 47 M. Schmidt, D. Breite, A. Prager, A. Schulze Self-cleaning studies on biocatalytic active polymer membranes Paper Nr. P1.12, 17th Aachener Membran Kolloquium, Aachen, Germany, 14.-15.11. (2018) 241-248 A. Schulze, S. Glaß, M. Kühnert Tailored synthesis of hydrogels and cryogels by the use of electron beam irradiation-mediated polymerization Proc. 6th Belgian Symposium on Tissue Engineering, Gent, Belgium, 21.-23.11. (2018) 48 104 Λ≈ 2.3 nm) multilayer thin,Munich, Germany, 24.-26.06. , Munich, Germany, 24.-26.06.

CONFERENCE PROCEEDINGS C. Bundesmann Schichten mit maßgeschneiderten Eigenschaften J. Oberfl. Techn. 59 (2019) 46-49 C. Bundesmann, R. Feder, T. Amelal, L. Pietzonka, D. Spemann Tailoring thin film properties by ion beam sputter deposition 14. ThGOT Thementage Grenz- und Oberflächentechnik und 6. Kolloquium Dünne Schichten in der Optik, Zeulenroda, 12.-14.03. (2019) C. Eichhorn, F. Scholze, C. Bundesmann, D. Spemann, H. Neumann, H. Leiter Two-photon laser-induced fluorescence diagnostics of a radiofrequency ion thruster: Measurements in Xenon and Krypton Paper Nr. IEPC-2019-503, 36th Int. Electric Propulsion Conf., Vienna, Austria, 15.-20.09. (2019) C. Eichhorn, F. Scholze, C. Bundesmann, D. Spemann, H. Neumann, H. Leiter Laser-induced fluorescence in the plume of a radiofrequency ion thruster: Measurements and excitation schemes Paper Nr. AIAA-2019-4168, AIAA Propulsion and Energy Forum and Exhibition, Indianapolis, IN, USA, 19.- 22.08. (2019) A. Finzel, G. Dornberg, S. Görsch, M. Mitzschke, J. Bauer, F. Frost Realization of depth reference samples with surfaces amplitudes between 0.1 nm and 5 nm EPJ Web. Conf. EOS Optical Technologies 215, Munich, Germany, 24.-26.06. (2019) 03004 S. Liedtke-Grüner, C. Grüner, A. Lotnyk, M. Mensing, J.W. Gerlach, P. Schumacher, B. Rauschenbach Texture formation in obliquely deposited metal thin films Z. Kristallogr. Suppl. 39 (2019) 69 P. Lorenz, I. Zagoranskiy, M. Ehrhardt, K. Zimmer Laser-induced large area sub-µm and nanostructuring of dielectric surfaces and thin metal layer Proc. SPIE 10906, Laser-based Micro- and Nanoprocessing XIII (2019) 109060T A. Lotnyk, T. Dankwort, I. Hilmi, L. Kienle, B. Rauschenbach In situ observations of the reversible vacancy ordering in layered chalcogenide-based thin films Proc. European Phase-Change and Ovonic Symposium, Grenoble, France, 08.-10.09. (2019) 86-87 A. Lotnyk, U. Ross, T. Dankwort, L. Kienle, B. Rauschenbach In situ observation of dynamic reconfiguration of van der Waals interfaces in 2D-bonded Ge-Sb-Te phase-change memory alloys Paper Nr. MS4.P001, Microscopy Conference 2019, Berlin, Germany, 01.-05.09. (2019) 153-154 D. Manova, S. Mändl In situ X-ray diffraction measurements during low energy ion beam nitriding & etching Z. Kristallogr. Suppl. 39 (2019) 47 M. Mensing, P. Schumacher, C. Grüner, S. Herath, A. Lotnyk, J.W. Gerlach, B. Rauschenbach Ion beam assisted thin film growth using mass separated low-energy nitrogen ions Z. Kristallogr. Suppl. 39 (2019) 56 G. Mirschel, O. Daikos, C. Steckert, T. Scherzer Monitoring of the application weight of laminating adhesives to PUR foam by NIR chemical imaging Proc. 18th Int. Conf. on Near Infrared Spectrosc. (2019) 163-168 H. Mueller, G. Böhm, Th. Arnold Next generation of a linear chirped slope profile fabricated by plasma jet machining Proc. SPIE 11171, Sixth European Seminar on Precision Optics Manufacturing (2019) 111710A M. Schmidt, D. Breite, A. Prager, A. Schulze Bioactive self-cleaning PVDF membrane filters Paper Nr. BIO-P126, European Polymer Congress 2019, Heraklion, Greece, 09.-14.06. (2019) 723 F. Scholze, D. Spemann, D. Feili Design and performance test of a RF plasma bridge neutralizer Paper Nr. IEPC-2019-475, 36th Int. Electric Propulsion Conf., Vienna, Austria, 15.-20.09. (2019) 106 , Munich, Germany, 24.-26.06.

TALKS Talks 2018 B. Abel* Counter-ion stabilized carbenes and room-temperatur conversion of carbon dioxide in ionic liquids: Theory and experiment Colloquium of Physikalische und Theoretische Chemie, Freie Universität Berlin, Berlin, Germany, 12.12.2018 B. Abel* Macromolecular organic compounds from the depths of Enceladus Seminar, UC Berkeley, Berkeley, CA, USA, 11.09.2018 B. Abel* Macromolecular organic compounds from the depths of Enceladus GDCh-Kolloquium, Universität Potsdam, Potsdam, Germany, 26.11.2018 B. Abel* Peptide/protein aggregation at surfaces: Blessing or curse? Miller Lunch Lectures, UC Berkeley, Berkeley, CA, USA, 18.09.2018 B. Abel* Peptides at Surfaces Seminar, Monash University, Melbourne, Australia, 20.11.2018 T. Albert*, A.J. Dittrich, T. Arnold, A. Lehmann, P.G. Braun Atmosphärisches Plasma zur Desinfektion von Schneidmesseroberflächen 9. Leipziger Tierärztekongress, Leipzig, Germany, 18.-20.01. 2018 T. Albert*, A.J. Dittrich, T. Arnold, A. Lehmann, P.G. Braun Antibakterielle Wirkung von kaltem atmosphärischem Plasma auf Slicermesseroberflächen 59. Arbeitstagung des Arbeitsgebietes Lebensmittelsicherheit und Verbraucherschutz der DVG, Garmisch- Partenkirchen, Germany, 25.-28.09.2018 A. Anders* Plasma-based and plasma-assisted deposition: A brief overview including cathodic arcs and magnetron sputtering Kolloquium, Technische Universität Bergakademie Freiberg, Freiberg, Germany, 07.05.2018 A. Anders* Plasma and ion beam tools to engineer surfaces and coatings 2018 IEEE 8th Int. Conf. on Nanomaterials: Applications & Properties, Zatoka, Ukraine, 09.-14.09.2018 A. Anders* Plasma potential distribution and electron heating in sputtering magnetrons Physikalisches Kolloquium, Christian Albrechts Universität zu Kiel, Kiel, Germany, 05.05.2018 A. Anders* Ionization and transport in magnetrons XXV. Erfahrungsaustausch Oberflächentechnologien mit Plasma- und Ionenstrahlprozessen, Mühlleithen, Germany, 19.-23.03.2018 A. Anders* Plasma physics of sputtering magnetrons revisited 16th Int. Conf. on Plasma Surface Engineering, Garmisch-Partenkirchen, Germany, 16.-21.09.2018 108

TALKS J. Bauer*, M. Ulitschka, F. Frost, T. Arnold, L. Alber, M. Sondermann, G. Leuchs Ultra-precision surface figuring of optical aluminium devices OSA Advanced Photonics Congress, Zurich, Switzerland, 02.-05.07.2018 D. Breite*, A. Prager, A. Schulze Charge selective polymer membranes with pH dependent selectivity Euromembrane 2018, Valencia, Spain, 09.-13.07.2018 S.P. Brühl*, S. Simison, L. Escalada, D. Manova, S, Mändl, L. Vaca, F. Soldera, M.A. Guitar Corrosion and wear properties of plasma nitrided 316L stainless steel Materials Science Engineering - European Congress and Exhibition on Advanced Materials and Processes, Darmstadt, Germany, 26.-28.09.2018 C. Bundesmann*, R. Feder, T. Lautenschläger, L. Pietzonka, D. Spemann, H. Neumann Unravelling the systematics in ion beam sputter deposition Symposium OCLA 2018 - Optical Coatings for Laser Applications, Buchs SG, Switzerland, 12.04.2018 C. Bundesmann*, F. Scholze, D. Spemann, F. Frost, H. Neumann Ion beam source developments at IOM Kolloquium, Forschungsinstitut RhySearch, Buchs SG, Switzerland, 11.04.2018 C. Bundesmann* Mehr als 50 Jahre Ionenquellenentwicklung in Leipzig (am Wissenschaftsstandort Permoserstraße) XXV. Erfahrungsaustausch Oberflächentechnologie mit Plasma- und Ionenstrahlprozessen, Mühlleithen, Germany, 20.-23.03.2018 C. Bundesmann* Mehr als 50 Jahre Entwicklung und Anwendung von Ionenstrahlquellen am Wissenschaftsstandort Permoserstraße (Ein Beitrag zur Geschichte des IOM) Kolloquium, Leibniz Institute of Surface Engineering (IOM), Leipzig, Germany, 27.09.2018 C. Bundesmann* The systematics of ion beam sputter deposition Summer School on the Physics of Plasma-Surface Interactions, National Research Nuclear University MEPhI, Moscow, Russia, 16.-20.07.2018 M. Burkhardt*, F. Koch, A. Kalies, L. Erdmann, M. Helgert, A. Pesch, O. Schönbrodt, F. Frost, F. Finzel, D. Lehr, A. Gatto, S. Sinzinger Angepasste Interferenzgitter für spektroskopische und Laser-Anwendungen von EUV bis NIR 119. Jahrestagung der deutschen Gesellschaft für angewandte Optik, Aalen, Germany, 21.-26.05.2018 M. Demmler, M. Nestler*, F. Frost Patterning and pattern transfer with ion beam etching SPIE Advanced Lithography, San Jose, CA, USA, 25.02.-01.03.2018 M. Deppe*, F. Tacken, J.W. Gerlach, D. Reuter, D.J. As Structural and optical characterisation of germanium doped cubic AlxGa1-xN grown by molecular beam epitaxy DPG-Frühjahrstagung der Sektion Kondensierte Materie, Berlin, Germany, 11.-16.03.2018 G. Dornberg*, A. Finzel, F. Koch, D. Lehr, T. Glaser, F. Frost Entwicklung einer RIBE-Technologie zur Strukturierung von dielektrischen Schichtsystemen mit höchster Tiefengenauigkeit XXV. Erfahrungsaustausch Oberflächentechnologie mit Plasma- und Ionenstrahlprozessen, Mühlleithen, Germany, 20.-23.03.2018 M. Ehrhardt, B. Han, I. Zagoranskiy, F. Frost, P. Lorenz, K. Zimmer* Generation of laser-induced periodic surface structures (LIPSS) in fused silica by single NIR nanosecond laser pulse irradiation in confinement 8th Int. Workshop on Laser Induced Periodic Surface Structures, Bochum, Germany, 27.-28.09.2018 110

TALKS S. Görsch*, A. Nickel, A. Finzel, G. Dornberg, F. Frost Generation of rotationally symmetric removal using (R)IBE on large surfaces: Mathematical introduction and practical realization XXV. Erfahrungsaustausch Oberflächentechnologie mit Plasma- und Ionenstrahlprozessen, Mühlleithen, Germany, 20.-23.03.2018 C. Grüner*, S. Liedtke-Grüner, S.G. Mayr, B. Rauschenbach Morphology of thin films formed by oblique physical vapor deposition Materials Science Engineering - European Congress and Exhibition on Advanced Materials and Processes, Darmstadt, Germany, 26.-28.09.2018 C. Grüner*, S. Liedtke, B. Rauschenbach Physical vapor deposition at oblique angles DPG-Frühjahrstagung der Sektion Kondensierte Materie, Berlin, Germany, 11.-16.03.2018 C. Grüner*, S. Liedtke, S.G. Mayr, B. Rauschenbach Anisotropies in on-lattice simulations of thin film growth Leibniz MMS Days 2018, Leipzig, Germany, 28.02.-02.03.2018 P. Hietschold*, M. Deuflhard, S. Riedel, M. Zink, S.G. Mayr Characteristics of modified hydrogels with and without incorporated magnetic nanoparticles Untergruppentreffen des DFG-Schwerpunktsprogramm 1681, Jülich, Germany, 12.06.2018 P. Hietschold*, S. Riedel, M. Deuflhard, M. Zink, S.G. Mayr Collagen hydrogels: Electron beam induced modification and nanoparticle composites 6. Kolloquium des DFG-Schwerpunktsprogramm 1681, Benediktbeuern, Germany, 28.09.2018 T. John*, B. Abel, L.L. Martin Amyloid-like aggregation of the antimicrobial peptide uperin 3.5 and its selectivity towards membranes 7th EuCheMS Chemistry Congress, Liverpool, UK, 26.-30.08.2018 T. John*, B. Abel, L.L. Martin Peptide aggregation near membranes 7th EuCheMS Chemistry Congress, European Young Chemist Award Competition Session, Liverpool, UK, 26.-30.08.2018 A. Kahnt*, S. Eigler, R. Fluynt, S. Naumov, B. Abel Radiation chemical GO reduction kinetics and mechanisms Bunsentagung 2018, Hannover, Germany, 10.-12.05.2018 F. Kazemi*, T. Arnold Ultra-precise machining of surfaces using microwave-driven reactive plasma etching XXVI. Erfahrungsaustausch Oberflächentechnologie mit Plasma- und Ionenstrahlprozessen, Mühlleithen, Germany, 20.-23.03.2018 T. Lautenschläger*, D. Spemann, J.W. Gerlach, E. Thelander, M. Mensing, L. Pietzonka, E. Rohkamm, C. Bundesmann Reactive ion beam sputter deposition of TiO2: Influence of target material and sputter gas XXV. Erfahrungsaustausch Oberflächentechnologie mit Plasma- und Ionenstrahlprozessen, Mühlleithen, Germany, 20.-23.03.2018 J. Lehnert*, D. Spemann, M.H. Hatahet, S. Mändl, P. With, M. Mensing, P. Schumacher, B. Rauschenbach Structured graphene films on silicon dioxide synthesized by carbon ion implantation XXV. Erfahrungsaustausch Oberflächentechnologie mit Plasma- und Ionenstrahlprozessen, Mühlleithen, Germany, 20.-23.03.2018 S. Liedtke*, Ch. Grüner, J.W. Gerlach, A. Lotnyk, B. Rauschenbach Texture, morphology and microstructure of nanostructured titanium thin films grown by oblique angle deposition DPG-Frühjahrstagung der Sektion Kondensierte Materie, Berlin, Germany, 11.-16.03.2018 112 G

TALKS D. Manova*, S. Mändl In-situ XRD during ion implantation and ion etching of Austenitic stainless steel Materials Science Engineering - European Congress and Exhibition on Advanced Materials and Processes, Darmstadt, Germany, 26.-28.09.2018 D. Manova*, S. Mändl In-situ x-ray diffraction measurements during low energy ion beam etching 16th Int. Conf. on Plasma Surface Engineering, Garmisch-Partenkirchen, Germany, 17.-21.09.2018 D. Manova*, D. Hirsch, S. Mändl In-situ XRD during ion implantation and ion etching XXV. Erfahrungsaustausch Oberflächentechnologie mit Plasma- und Ionenstrahlprozessen, Mühlleithen, Germany, 20.-23.03.2018 A. Mayer*, W. Ai, J. Rond, J. Stabs, C. Steinberg, M. Papenheim, H.-C. Scheer, M. Torman, A. Cian, J. Zajadacz, K. Zimmer Electrically-assisted nanoimprint of block-copolymers 62nd Int. Conf. on Electron, Ion and Photon Beam Technology and Nanofabrication, Rio Mar, Puerto Rico, 29.05.-01.06.2018 M. Mensing*, P. Schumacher, J.W. Gerlach, S. Rauschenbach, S. Herath, A. Lotnyk, B. Rauschenbach Investigation of the influence of molecular and atomic nitrogen ion species during epitaxial nitride thin film growth 15th European Vacuum Conf., Geneva, Switzerland, 17.-22.06.2018 M. Mitzschke*, F. Carstens, H. Ehlers, F. Frost Optisches in-situ Monitoring von reaktiven Ionenstrahlprozessen: Fortschrittsbericht XXV. Erfahrungsaustausch Oberflächentechnologie mit Plasma- und Ionenstrahlprozessen, Mühlleithen, Germany, 20.-23.03.2018 M. Panjan*, A. Anders The role of spokes on energy and transport of ions in magnetron sputtering 15th European Vacuum Conf., Geneva, Switzerland, 17.-22.06.2018 T. Pelras, S. Glaß, A. Schulze, C. Elsner, T. Scherzer*, B. Abel UV-cured hydrogels based on low-molecular weight poly(ethylene glycol) diacrylate for use as transparent drug delivery system Int. Symposium of Photopolymer Science, Wuxi, China, 23.-25.04.2018 P. Räcke*, D. Spemann, N. Raatz, R. Staacke, J.W. Gerlach, B. Rauschenbach, J. Meijer A concept for deterministic ion implantation by image charge detection 14th Int. Conf. on Nuclear Microprobe Technology and Applications, Guildford, UK, 08.-13.07.2018 P. Räcke*, D. Spemann, J.W. Gerlach, B. Rauschenbach, J. Meijer A concept for deterministic ion implantation by image charge detection 21st Int. Conf. on Ion Beam Modification of Materials, San Antonio, TX, USA, 24.-29.06.2018 S. Riedel*, S.G. Mayr Electron-beam-induced crosslinking of hydrogels: Modifications and application 3rd Soft Matter Day 2018, Leipzig, Germany, 06.07.2018 S. Riedel*, B. Heyart, K. Apel, E.I. Wisotzki, S.G. Mayr Smart gelatin hydrogels: Modification by electron irradiation towards stimuli-responsive elements 2018 MRS Spring Meeting & Exhibit, Phoenix, AZ, USA, 02.-06.04.2018 S. Riedel*, K. Bela, M. Tadsen, C. Krömmelbein, C. Suckfüll, J. Zajadacz, T. Kunschmann, E.I. Wisotzki, S.G. Mayr Electron irradiation assisted crosslinking of hydrogels: Reagent-free modification towards functional scaffolds 2018 MRS Spring Meeting & Exhibit, Phoenix, AZ, USA, 02.-06.04.2018 114

TALKS M. Ulitschka*, J. Bauer, F. Frost, Th. Arnold Eigenschaftsoptimierung Novolak-basierter Photolacke für die Ionenstrahlplanarisierung von Al- Optiken XXV. Erfahrungsaustausch Oberflächentechnologie mit Plasma- und Ionenstrahlprozessen, Mühlleithen, Germany, 20.-23.03.2018 G. Wang*, Q. Nie, X. Shen, Y. Lu, A. Lotnyk Controllable crystallization and interface microstructure stability of new phase-change films 15th Int. Conf. on the Physics of Non-Crystalline Solids & 14th European Society of Glass Conf., Saint Malo, France, 09.-13.07.2018 A. Weidt*, S.G. Mayr, M. Zink Organization of fibronectin and NIH/3T3 fibroblasts on bulk microgrooved TiO2 DPG-Frühjahrstagung der Sektion Kondensierte Materie, Berlin, Germany, 11.-16.03.2018 S. Zahn* Deep eutectic solvents: Similia similibus solvuntur? 27th Conf. on Molten Salts and Ionic Liquids, Lisboa, Portugal, 07.-12.10.2018 S. Zahn* Modellierung chemischer Reaktionen am Computer Tag der Technik, Landesschule Pforta, Naumburg, Germany, 25.10.2018 K. Zimmer*, C. Petersen, J. Zajadacz, P. Lorenz Origami folding of laser-cut polymer foils 2nd Int. Workshop on Advanced 3D Patterning, Dresden, Germany, 04.-05.10.2018 K. Zimmer*, J. Zajadacz, A. Mayer, C. Steinberg, H.-C. Scheer Towards fast nanopattern fabrication by local laser annealing of diblock copolymer (BiCBP) films 2018 E-MRS Spring Meeting, Strasbourg, France, 18.-22.06.2018 B. Zitouni*, S. Mändl, D. Manova Ions and surface interactions: a new erosion modelling approach 7th Russian-German Conf. on Electric Propulsion and Their Application, Rauischholzhausen, Germany, 21.- 26.10.2018 S. Zöhrer*, A. Anders, R. Franz Time and energy-resolved average ion charge states in pulsed cathodic vacuum arc plasmas of Nb- Al cathodes as a function of Ar pressure 28th Int. Symposium on Discharges and Electrical Insulation in Vacuum, Greifswald, Germany, 23.- 28.09.2018 S. Zöhrer, A. Anders, D. Holec, R. Franz* Time-resolved analysis of the cathodic arc plasma from Nb-Al cathodes AVS 65th Int. Symposium & Exhibition 2018, Long Beach, CA, USA, 21.-26.10.2018 S. Zöhrer*, A. Anders, R. Franz Time-resolved ion energy and charge state distributions in pulsed cathodic arc plasmas of Nb-Al cathodes in high vacuum 45th Int. Conf. on Metallurgical Coatings and Thin Films, San Diego, CA, USA, 23.-27.04.2018 2019 A. Anders* Metal plasmas for thin film synthesis XXVI. Erfahrungsaustausch Oberflächentechnologie mit Plasma- und Ionenstrahlprozessen, Mühlleithen, Germany, 05.-07.03.2019 A. Anders* Electron heating in magnetron sputtering 19. Fachtagung für Plasmatechnologie, Cottbus, Germany, 17.-19.06.2019 116

TALKS H. Bryja*, C. Grüner, J.W. Gerlach, M. Behrens, B. Rauschenbach, A. Lotnyk Investigation of bipolar resistive switching mechanisms in Ge2Sb2Te5 thin films using different electrode materials Int. Conf. on Memristive Materials, Devices & Systems 2019, Dresden, Germany, 08.-11.07.2019 H. Bryja*, C. Grüner, J. W. Gerlach, M. Behrens, B. Rauschenbach, A. Lotnyk Investigation of bipolar resistive switching mechanisms in Ge2Sb2Te5 thin films using different electrode materials 15th Meeting of the Working Group: Materials for Nonvolatile Memories of the GMM - VDE/VDI, Darmstadt, Germany, 04.06.2019 C. Bundesmann* Tutorial: The systematics of ion beam sputtering for deposition of thin films with tailored properties XXVI. Erfahrungsaustausch Oberflächentechnologie mit Plasma- und Ionenstrahlprozessen, Mühlleithen, Germany, 05.-07.03.2019 C. Bundesmann*, T. Amelal, J. Bernstein, M. Mateev, L. Pietzonka, D. Spemann Reactive ion beam sputter deposition of SiO2 and TiO2 thin films Int. Conf. on Reactive Sputter Deposition RSD, Braunschweig, Germany, 05.-06.12.2019 C. Bundesmann*, T. Amelal, L. Pietzonka, D. Spemann, H. Neumann Tailoring optical and other properties of TiO2 films by ion beam sputter deposition 8th Int. Conf. on Spectroscopic Ellipsometry, Barcelona, Spain, 26.-31.05.2019 C. Bundesmann*, R. Feder, T. Amelal, L. Pietzonka, D. Spemann Tailoring thin film properties by ion beam sputter deposition 14. ThGOT Thementage Grenz- und Oberflächentechnik und 6. Kolloquium Dünne Schichten in der Optik, Zeulenroda, Germany, 12.-14.03.2019 C. Bundesmann*, R. Feder, T. Lautenschläger, L. Pietzonka, D. Spemann Options to tailor thin film properties by ion beam sputter deposition (IBSD) Int. Conf. on Sputter Technology, Braunschweig, Germany, 19.-20.06.2019 M. Ehrhardt*, P. Lorenz, S. Lai, K. Zimmer Excimer laser generated LIPSS in micro-patterned and geometrical-restricted polymer thin films 9th Int. LIPSS Workshop 2019, Ljubljana, Slovenia, 26.-27.09.2019 Ehrhardt, S. Lai, P. Lorenz, J. Zajadacz, B. Han, K. Zimmer* Fabrication of hierarchical structures by LIPSS formation on pre-patterned polymer 2019 EMRS Spring Meeting, Nice, France, 27.-31.05.2019 C. Eichhorn*, F. Scholze, C. Bundesmann, D. Spemann, H. Neumann, H. Leiter Laser-induced fluorescence in the plume of a radiofrequency ion thruster: Measurements and excitation schemes AIAA Propulsion and Energy Forum and Exhibition, Indianapolis, IN, USA, 19.-22.08.2019 C. Eichhorn*, F. Scholze, C. Bundesmann, D. Spemann, H. Leiter, H. Neumann Ion thruster plume diagnostics in krypton using TALIF XXVI. Erfahrungsaustausch Oberflächentechnologie mit Plasma- und Ionenstrahlprozessen, Mühlleithen, Germany, 05.-07.03.2019 C. Eichhorn*, F. Scholze, C. Bundesmann, D. Spemann, H. Neumann, H. Leiter Two-photon laser-induced fluorescence diagnostics of a radiofrequency ion thruster: Measurements in Xenon and Krypton 36th Int. Electric Propulsion Conf., Vienna, Austria, 15.-20.09.2019 A. Finzel, G. Dornberg, S. Görsch, M. Mitzschke, J. Bauer, F. Frost* Realization of depth reference samples with surfaces amplitudes between 0.1 nm and 5 nm EOS Optical Technologies: Optofluidics and Manufacturing, Tolerancing, and Testing of Optical Systems, München, Germany, 24.-27.06.2019 118

TALKS S. Liedtke-Grüner*, C. Grüner, A. Lotnyk, M. Mensing, J.W. Gerlach, P. Schumacher, B. Rauschenbach Texture formation in obliquely deposited metal thin films 27th Annual Meeting of the German Crystallographic Society, Leipzig, Germany, 25.-28.03.2019 O. Lorenz*, M. Wagner, B. Abel Activation of Platinum thin film electrodes of solid acid fuel cells via cyclic voltammetry 11th Central European Meeting on Molecular Electrochemistry 2019, Chemnitz, Germany, 17.-19.11.2019 P. Lorenz*, M. Kloeppel, J. Zajadazc, I. Zagoranskiy, M. Ehrhardt, K. Zimmer, B. Hopp, H. Bing Self-assembly laser-induced nanostructuring of dielectric surfaces - a review DPG-Frühjahrstagung der Sektion Materie und Kosmos, München, Germany, 17.-23.03.2019 P. Lorenz*, K. Zimmer, I. Zagoranskiy, M. Ehrhardt Large area sub-µm and nanostructuring of dielectric surfaces and thin metal layers by ns laser radiation SPIE LASE, San Francisco, CA, USA, 05.-07.02.2019 A. Lotnyk*, M. Behrens, I. Hilmi, B. Rauschenbach Epitaxial chalcogenide-based thin films and heterostructures 15th Meeting of the Working Group: Materials for Nonvolatile Memories of the GMM - VDE/VDI, Darmstadt, Germany, 04.06.2019 A. Lotnyk* Nanoscale characterization of phase change materials for memory applications Seminar, Fakultät für Maschinenbau, Technische Universität, Chemnitz, Germany, 22.08.2019 A. Lotnyk*, T. Dankwort, L. Kienle, B. Rauschenbach In situ observations of the reversible vacancy ordering in layered chalcogenide-based thin films European Phase-Change and Ovonic Symposium, Grenoble, France, 08.-10.09.2019 S. Mändl*, D. Manova Dynamic OES during high voltage pulses XXVI. Erfahrungsaustausch Oberflächentechnologie mit Plasma- und Ionenstrahlprozessen, Mühlleithen, Germany, 05.-07.03.2019 D. Manova, S. Mändl* In situ X-ray diffraction measurements during low energy ion beam nitriding & etching 27th Annual Meeting of the German Crystallographic Society, Leipzig, Germany, 25.-28.03.2019 A. Mayer*, J. Rond, J. Staabs, M. Leifels, H.-C. Scheer, J. Zajadacz, M. Ehrhardt, P. Lorenz, K. Zimmer Multiple replication of hierarchical structures from polymer masters with anisotropy The 63rd Int. Conf. on Electron, Ion and Photon Beam Technology & Nanofabrication, Minneapolis, MN, USA, 28.-31.05.2019 M. Mensing*, P. Schumacher, J.W. Gerlach, S. Herath, A. Lotnyk, B. Rauschenbach Mass selected low energy ion-assisted growth of epitaxial GaN thin films: Impact of the nitrogen ion species Ion beam physics workshop 2019, Dresden, Germany, 24.-26.06.2019 M. Mensing*, P. Schumacher, C. Grüner, S. Herath, A. Lotnyk, J.W. Gerlach, B. Rauschenbach Mass separated low-energy nitrogen ion assisted film growth DPG-Frühjahrstagung der Sektion Kondensierte Materie, Regensburg, Germany, 31.03.-05.04.2019 M. Mensing*, P. Schumacher, C. Grüner, S. Herath, A. Lotnyk, J.W. Gerlach, B. Rauschenbach Ion beam assisted thin film growth using mass separated low-energy nitrogen ions 27th Annual Meeting of the German Crystallographic Society, Leipzig, Germany, 25.-28.03.2019 K. Monakhov* Development of polyoxometalate compounds for the 'more than moore' technology Kolloquium der Fakultät für Chemie & Mineralogie, Universität Leipzig, Leipzig, Germany, 05.06.20192019 120

TALKS A. Schulze* Bioactive polymer surfaces for medical application Integrierter Graduiertenkolleg Matrixengineering - Materials in Medicine, Transregio 67, Leipzig, Germany, 28.11.2019 A. Schulze*, S. Nieß, P. Langowski, S. Glaß Photoactive polymer membranes for degradation of pharmaceuticals from water 14th Int. Conf. on Catalysis in Membrane Reactors, Eindhoven, Netherlands, 08.-11.07.2019 D. Spemann* Deterministic ion implantation: Approaches and challenges XXVI. Erfahrungsaustausch Oberflächentechnologie mit Plasma- und Ionenstrahlprozessen, Mühlleithen, Germany, 05.-07.03.2019 M. Ulitschka*, J. Bauer, F. Frost, T. Arnold Reactive ion beam etching-based planarization of optical aluminium surfaces SPIE Optics + Optoelectronics, EUV and X-ray Optics: Synergy between Laboratory and Space, Prague, Czech Republic, 01.-04.04.2019 M. Ulitschka*, J. Bauer, F. Frost, T. Arnold Reactive ion beam etching - based finishing of optical Aluminium surfaces EOS Optical Technologies: Optofluidics and Manufacturing, Tolerancing, and Testing of Optical Systems, München, Germany, 24.-27.06.2019 N. Wilharm*, T. Fischer, W. Knolle, F. Ott, A. Beck-Sickinger, M. Zink, S. Mayr A biocompatible reversible thermal actuator with tunable transition temperature 5th Euro BioMAT 2019, Weimar, Germany, 08.-09.05.2019 S. Zahn* Deep eutectic solvents: Like dissolve like? 1st Int. Meeting on Deep Eutectic Systems, Lisboa, Portugal, 24.-27.06.2019 S. Zahn* Deep eutectic solvents: Like dissolves like 11th Central European Meeting on Molecular Electrochemistry 2019, Chemnitz, Germany, 17.-19.11.2019 S. Zahn* Deep eutectic solvents: Like dissolves like? 5. Int. Conf. on Ionic Liquid-Based Materials, Jussieu, Paris, France, 04.-08.11.2019 122

POSTERS A.J. Dittrich*, T. Albert, A. Lehmann, T. Arnold, P.G. Braun Einfluss verschiedener Träger- und Reaktivgase auf die antimikrobielle Wirkung von kaltem atmosphärischem Plasma auf Slicermesseroberflächen 59. Arbeitstagung des Arbeitsgebietes Lebensmittelsicherheit und Verbraucherschutz der DVG, Garmisch- Partenkirchen, Germany, 25.-28.09.2018 A.J. Dittrich*, T. Albert, A. Lehmann, T. Arnold, P.G. Braun Antimicrobial effect of cold atmospheric plasma jet treatment on cutting blade surfaces 26th Int. ICFMH Conf. FoodMicro 2018, Berlin, Germany, 03.-06.09.2018 J. Edelmann*, E. Gärtner, U. Eckert, J. Griebel Tool System for UV induced micro moulding of biomedical disposables EUSPEN, 18th Int. Conf. & Exhibition, Venice, Italy, 04.-08.06.2018 R. Flyunt*, W. Knolle, A. Kahnt, A. Lotnyk, S. Eigler, B. Abel Optimized reduction of graphene oxide by electron-beam irradiation PULS-2018 - Pulse Investigations in Chemistry, Physics, and Biology with RKCM-2018 Reaction Kinetics in Condensed Matter, Lodz, Poland, 02.09.-07.09.2018 S. Friebe*, J. Haunschild, C.D. Etz, S.G. Mayr Human aorta under tensile stress 9th Annual Symposium Physics of Cancer, Leipzig, Germany, 24.09.-26.09.2018 S. Friebe*, J. Haunschild, C.D. Etz, S.G. Mayr Human aorta under tensile stress 3rd Soft Matter Day 2018, Leipzig, Germany, 06.07.2018 S. Friebe*, S. Weigel, M. Francke, M. Zink, S.G. Mayr TiO2 nanotube arrays as platform for environmental scanning electron microscopy studies - from imaging to mechanical response 14. Research Festival, Leipzig, Germany, 19.01.2018 S. Glaß*, B. Trinklein, B. Abel, A. Schulze TiO2 as photosensitizer and photoinitiator for the synthesis of photoactive TiO2-PEGDA hydrogels 6th Belgian Symposium on Tissue Engineering, Ghent, Belgium, 22.-23.11.2018 C. Hackl*, J. Griebel, C. Elsner, J. Edelmann, B. Abel Microstructured multifunctional polymer chips by UV-photopolymerization injection molding EUSPEN, 18th Int. Conf. & Exhibition, Venice, Italy, 04.-08.06.2018 P. Hietschold*, S. Riedel, M. Deuflhard, M. Zink, S.G. Mayr Collagen hydrogels: Electron beam induced modification and nanoparticle composites 6. Kolloquium des DFG-Schwerpunktsprogramm 1681, Benediktbeuern, Germany, 26.-28.09.2018 P. Hietschold*, S. Riedel, S.G. Mayr, M. Zink Collagen hydrogels: Electron beam induced modification and nanoparticle composites 3rd Soft Matter Day, Leipzig, Germany, 06.07.2018 I. Hilmi*, A. Lotnyk, J.W. Gerlach, P. Schumacher, B. Rauschenbach Two-dimensional growth of three-dimensionally bonded GeTe DPG-Frühjahrstagung der Sektion Kondensierte Materie, Berlin, Germany, 11.-16.03.2018 Q. Ji*, Z. Yang, H. Wang, X. Wang, A. Anders Cathodic arc deposition of V2O3 films and their application in quench protection of high-temperature superconducting magnets Gordon Research Conference (GRC) Plasma Processing Science - Fundamental Insights in Plasma Processes, Smithfield, RI, USA, 05.-10.08.2018 F. Kazemi*, T. Arnold Surface machining of N-BK7® using microwave-driven plasma etching 16th Int. Conf. on Plasma Surface Engineering, Garmisch-Partenkirchen, Germany, 17.-21.09.2018 124

POSTERS S. Riedel*, C. Krömmelbein, K. Bela, C. Suckfüll, J. Zajadacz, S.G. Mayr Electron-irradiated hydrogels: Reagent-free modification towards biomedical applications 4th Euro Bio-inspired Materials, Potsdam, Germany, 19.-22.03.2018 S. Riedel*, C. Krömmelbein, T. Kunschmann, S.G. Mayr Electron irradiation of collagen: Reagent-free crosslinking towards tailored matrices 14. Research Festival, Leipzig, Germany, 19.01.2018 S. Riedel*, C. Krömmelbein, K. Bela, C. Suckfüll, J. Zajadacz, S.G. Mayr Electron-irradiated hydrogels: Reagent-free modification towards biomedical applications DPG-Frühjahrstagung der Sektion Kondensierte Materie, Berlin, Germany, 11.-16.03.2018 S. Riedel*, C. Krömmelbein, K. Bela, C. Suckfüll, J. Zajadacz, S.G. Mayr Electron-irradiated hydrogels: Reagent-free modification towards biomedical applications 9th Annual Symposium Physics of Cancer, Leipzig, Germany, 24.-26.09.2018 M. Schmidt*, D. Breite, A. Prager, A. Schulze Self-cleaning studies on biocatalytic active polymer membranes 17. Aachener Membran Kolloquium, Aachen, Germany, 14.-15.11.2018 A. Schulze*, L. Drößler, S. Weiß, M. Went, A. Abdul Latif, D. Breite, K. Fischer Functionalization in pilot scale: Roll-to-roll electron beam system with in-line contact angle determination 17th Aachener Membran Kolloquium, Aachen, Germany, 14.-15.11.2018 C. Steier*, A. Allézy, A. Anders, K. Baptiste, E. Buice, K. Chow, G. Cutler, R. Donahue, D. Filippetto, J. Harkins, T. Hellert, M. Johnson, J.-Y. Jung, S. Leemann, D. Leitner, M. Leitner, T. Luo, H. Nishimura, T. Oliver, O. Omolayo, J. Osborn, et al. Status of the conceptual design of ALS-U 9th Int. Particle Accelerator Conf., Vancouver, Canada, 29.04.-04.05.2018 M. Ulitschka*, J. Bauer, F. Frost, U. Decker, I. Reinhardt, Th. Arnold Optimization of novolak-based photoresists for ion beam planarization of aluminium mirrors 16th Int. Conf. on Plasma Surface Engineering, Garmisch-Partenkirchen, Germany, 17.-21.09.2018 A. Weidt*, M. Mensing, J. Lehnert, S. Mändl, M. Zink, S.G. Mayr Carbon implantation of TiO2 nanotubes for biomedical applications 9th Annual Symposium Physics of Cancer, Leipzig, Germany, 25.09.2018 A. Weidt*, M. Mensing, J. Lehnert, S. Mändl, M. Zink, S.G. Mayr Carbon implantation of TiO2 nanotubes for biomedical applications 3rd Soft Matter Day, Leipzig, Germany, 06.07.2018 A. Weidt*, S.G. Mayr, M. Zink Organization of fibronectin and NIH/3T3 fibroblasts on bulk microgrooved TiO2 14. Research Festival, Leipzig, Germany, 19.01.2018 A. Weidt*, M. Mensing, J. Lehnert, S. Mändl, M. Zink, S.G. Mayr Carbon implantation of TiO2 nanotubes Annual BuildMoNa Conf., Leipzig, Germany, 19.03.2018 N. Wilharm*, S. Riedel, W. Knolle, F. Ott, A. Beck-Sickinger, M. Zink, S.G. Mayr Electron irradiated elastin/collagen hydrogels 9th Annual Symposium Physics of Cancer, Leipzig, Germany, 24.-26.09.2018 N. Wilharm*, S. Riedel, W. Knolle, F. Ott, A. Beck-Sickinger, M. Zink, S.G. Mayr Electron irradiated elastin/collagen hydrogels 3. Soft Matter Day 2018, Leipzig, Germany, 06.07.2018 N. Wilharm*, S. Riedel, W. Knolle, M. Zink, S.G Mayr A tissue model with tunable properties by electron irradiation of elastin-collagen hydrogels 14. Research Festival, Leipzig, Germany, 19.01.2018 126

POSTERS S. Liedtke-Grüner*, C. Grüner, A. Lotnyk, M. Mensing, J.W. Gerlach, P. Schumacher, B. Rauschenbach Texture formation in obliquely deposited metal thin films 27th Annual Meeting of the German Crystallographic Society, Leipzig, Germany, 25.-28.03.2019 P. Lorenz*, M. Kloeppel-Gersdorf, I. Zagoranskiy, M. Ehrhardt, F. Frost, K. Zimmer Laser-induced melting and reshaping of µm- and sub-µm pre-structured chromium layers: experiment and theory 2019 EMRS Spring Meeting, Nice, France, 27.-31.05.2019 P. Lorenz*, M. Himmerlich, M. Ehrhardt, M. Taborell, B. Hopp, K. Zimmer Laser fabrication of black copper surfaces to reduce the optical reflectivity and secondary electron yield 2019 EMRS Spring Meeting, Nice, France, 27.-31.05.2019 A. Lotnyk*, I. Hilmi, U. Ross, B. Rauschenbach Nanoscale characterization of chalcogenide-based heterostructures by advanced electron microscopy 6th Nano Today Conf., Lisboa, Portugal, 16.-20.06.2019 A. Lotnyk*, U. Ross, T. Dankwort, L. Kienle, B. Rauschenbach In situ observation of dynamic reconfiguration of van der Waals interfaces in 2D-bonded Ge-Sb-Te phase-change memory alloys Microscopy Conference 2019, Berlin, Germany, 01.-05.09.2019 M. Mensing*, P. Schumacher, C. Grüner, S. Herath, A. Lotnyk, J.W. Gerlach, B. Rauschenbach Ion beam assisted thin film growth using mass separated low-energy nitrogen ions 27th Annual Meeting of the German Crystallographic Society, Leipzig, Germany, 25.-28.03.2019 M. Schmidt*, D. Breite, A. Prager, A. Schulze Bioactive self-cleaning PVDF membrane filters European Polymer Congress 2019, Heraklion, Greece, 09.-14.06.2019 S. Zahn*, S. Kühne, S. Frenzel Datenmanagement im Rahmen eines Transregios an der Universität Leipzig, der TU Chemnitz und dem Leibniz Institut für Oberflächenmodifizierung e.V. (IOM) 1. sächsische FDM-Tagung, Dresden, Germany, 19.09.2019 J. Zajadacz*, K. Zimmer, P. Lorenz, A. Mayer, M. Papenheim, H.-C. Scheer Shear force measurement of actuated, gecko-inspired adhesion elements with hierarchical PDMS pattern 45th Int. Conf. on Micro & Nano Engineering, Rhodes, Greece, 23.-26.09.2019 128 DE

IMPRINT Leibniz-Institut für Oberflächenmodifizierung e.V. Leibniz Institute of Surface Engineering (IOM) Permoserstr. 15 04318 Leipzig, Germany Director and CEO Prof. Dr. André Anders Phone: +49 (0) 341 235 - 2308 Fax: +49 (0) 341 235 - 2313 andre.anders@iom-leipzig.de Public Relations Yvonne Bohne Phone: +49 (0)341 235 - 3175 Fax: +49 (0)341 235 - 2313 yvonne.bohne@iom-leipzig.de www.iom-leipzig.de All rights reserved. Reproduction requires the permission of the director of the institute. © Leibniz Institute of Surface Engineering (IOM), Leipzig 2020 Image directory Cover: Center: Interior view of a system for ion-beam assisted thin film deposition (© IOM/ Photo: J.W. Gerlach); Down left: View into a Kaufman-type broad-beam ion source (© IOM/ Photo: S. Görsch); Down center: “Inspired by Gecko foot”: SEM image of laser induced periodic surface structures generated on micrometer size columns (© IOM/ Photo: I. Mauersberger); Down right: SEM image of anodic ZnO crystallized in water vapor (© IOM/ Photo: A. Prager) S. 6: IOM-Building 16.2 (© IOM/ Photo: Y. Bohne) S. 16: Image of an ion extraction grid system of a broad beam ion source (Kaufman-type) after a very long process time with intensive redeposition by etched material (© IOM/ Photo: A. Finzel) S. 58: Entry grid of a quadrupole mass filter system for a hyperthermal ion beam (© IOM/ Photo: M. Mensing) S. 74: SEM image of various morphologies of ZnO (© IOM/ Photo: A. Prager) S. 82: Peron on the IOM-building 18.0 (© IOM/ Photo: Y. Bohne) S. 90: Quadrupole mass filter system as seen by a low-energy ion right before entering (© IOM/ Photo: M. Mensing) Print FISCHER druck&medien OHG | Sestewitzer Straße 18 | 04463 Großpösna

Research & Development Ultra-precision machining with ions and plasma Structuring and thin film analysis Thin film deposition and nanostructures Electron beam and photonic technologies Functional layers Functional nano- and microstructured systems < < M H a g d e a lle b u r g < H a n n o v e r < N ürnberg < M ünchen t r e a l r t n C e a n e u n y < C e < C i t A d a il w a e r a ll e e r Berlin > Airport Leipzig-Halle A 9 Leipzig Northeast B 87 Tra m 3 3E // n t a t i o s y Leipzig East Permoserstraße B 6 A 1 4 Torg a uer Str. B us 7 7 9 0 // Wissenschaftspark Leipzig D r e s d e n > Leibniz Institute of Surface Engineering (IOM) Leibniz-Institut für Oberflächenmodifizierung e. V. Permoserstraße 15 04318 Leipzig Germany Phone: +49 (0) 341 235-2308 Fax: +49 (0) 341 235-2313 www.iom-leipzig.de