Horizons Symposium: Electronic & energy materials

Horizons Symposium: Electronic & energy materials 25-26 September 2023 Berlin, Germany

Horizons Symposium: Electronic & energy materials 25-26 September 2023 | Berlin, Germany Book of Abstracts

Welcome

Dear Colleagues, A very warm welcome to the 2023 Horizons Symposium: Electronic and energy materials. Co-hosted by Materials Horizons and Nanoscale Horizons, this event aims to showcase a wide variety of cutting-edge work in the areas of electronic and photonic materials, and materials for energy applications, at the interface of materials and nanoscience. The focus of this symposium is to highlight how materials science is contributing to some of the biggest global challenges of our time, bringing together leading researchers and emerging investigators from a broad range of backgrounds and from across the globe. We strongly encourage delegates to raise questions to our speakers and poster presenters during the discussion and throughout our dedicated poster sessions to spark collaborations and new ideas across the community. In addition to our stellar line up of invited speakers, we had an overwhelming response to the call for poster abstracts, and we encourage you to visit them at the meeting. We hope there will be many opportunities during the meeting for informal discussions where you can make new connections as well as renew old ones. Over the last several years, Materials Horizons and Nanoscale Horizons have rapidly established themselves amongst the most important publication venues for research in materials and nanoscience. The symposium will provide a way for our wide community to get in touch with the Editorial Board members, journal editors and fellow researchers across a broad range of topics in materials and nanoscience. It will also be a great way to learn more about the journals and hear about exciting new projects to look out for. We’d like to thank each of the speakers, poster presenters and participants for all their contributions. We would especially like to extend our thanks to Professor Norbert Koch for his dedication and hard work as chair of this meeting, as well as to the scientific committee for their enthusiastic commitment to the symposium and its participants. Again, welcome to what promises to be an exciting symposium. We hope that this event will act as a springboard for future activities and will help in fostering new research collaborations.

Professor Katharina Landfester Editorial Board Chair, Nanoscale Horizons Max Planck Institute for Polymer Research

Professor Martina Stenzel Editorial Board Chair, Materials Horizons University of New South Wales

Dr Michaela Mühlberg Executive Editor, Materials Horizons Royal Society of Chemistry

Dr Heather Montgomery Managing Editor, Nanoscale Horizons Royal Society of Chemistry

Speakers list

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Highly conductive PEDOT-based materials for thermoelectric and photovoltaic applications Renaud Demadrille CEA, France Emerging microporous membranes for energy-relevant applications Zhongyi Jiang Tianjin University, China Electronic/ionic, plasmonic and photonic neuromorphic device concepts for artificial neural networks Emil List-Kratochvil Humboldt-Universität zu Berlin, Germany Colloidal synthesis approach for energy materials Yan Lu Helmholtz-Zentrum Berlin für Materialien und Energie, Germany Phases, polytypes and polymorphs: how to make what you want in nanocrystal synthesis Janet Macdonald Vanderbilt University, USA Exploring the solar cell materials landscape with NOMAD Jose Marquez Prieto Humboldt University of Berlin, Germany Semi-paracrystallinity in semiconducting polymers for photovoltaics Jaime Martin University of La Coruña, Spain

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Soft PhotoElectroChemical systems for solar fuels Erin Ratcliff University of Arizona, USA

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An enabling thin-film deposition technique for hybrid optoelectronic devices

Adrienne Stiff-Roberts Duke University, USA

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Crystal structures of molecular semiconductors: control and prediction Kazuo Takimiya Tohoku University and RIKEN CEMS, Japan FAIRification of research data management in halide perovskite photovoltaics Eva Unger Lund University, Sweden Vapor deposition of metal halide perovskites – photovoltaics and beyond Yana Vayznof Technical University of Dresden, Germany Modifications of nanostructured TiO 2 for efficient photocatalytic and photoelectrochemical green hydrogen production Ewa Wierzbicka Military University of Technology, Warsaw, Poland

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Poster presentations

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The role of grain boundaries and dislocations in various solar-cell materials on the corresponding device performance Daniel Abou-Ras Helmholtz-Zentrum Berlin, Germany Watching ternary oxides with dual eyes: two-colour xes studies of chemical transformations & electronic structure in ferric pseud brookite (Fe 2 TiO 5 ) photoanodes Devi Prasad Adiyeri Saseendran Department of Chemistry, University of Zurich, Switzerland The influence of gas cluster ion beam surface etching on the chemical and electronic structure of perovskite Emily Albert Humboldt-Universität zu Berlin, Germany Core-shell phase segregation in Nanocrystals: A pathway for unlocking new internal quantum yield efficiencies Fernando Arteaga Cardona KIT-IMT, Germany Electrochemical and structural study on a feiii-ionic liquid redox electrolyte Christian Balischewski University of Potsdam, Germany Excitonics of Squaraine Dunes Frank Balzer University of Southern Denmark, Centre for Photonics Engineering, Denmark Hydroxide-based high entropy metal organic framework for oxygen evolution reaction (OER) and the role of Nucleophilicity in OER Biswajit Bhattacharya Bundesanstalt für Materialforschung und -prüfung, Germany Growing of anisotropic low melting transparent metal halides in ionic liquids for superior ion conduction Biswajit Bhattacharyya Institute of Chemistry, University of Potsdam, Germany

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Emerging field of few-layered intercalated 2D materials Qing Cao Free University of Berlin, Germany

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Phase transformation from solvate phase to perovskite: Phase diagram of a mixed halide system Anton Dzhong Helmholtz-Zentrum Berlin, Germany

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Ground state charge transfer and photoinduced charge separation at perovskite/ organic interfaces Lennart Frohloff Humboldt-Universität zu Berlin, Germany Inkjet-printed organic synaptic diodes based on mixed ionic-electronic conductors Fabian Gärisch Humboldt-Universität zu Berlin, Germany Surface doping of rubrene single crystals by molecular electron donors and acceptors Christos Gatsios Humboldt Universität zu Berlin, Germany Formulating a free-standing bi-layer composite solid-state electrolyte incorporating Al-doped LLZO (Al-LLZO) for solid state lithium- metal batteries Adere Tarekegne Habte Ming Chi University of Technology, Chinese Taipei Performance limiting factors in ultra-low-bandgap PTB7-Th:COTIC-4F based organic solar cells Guorui He University of Potsdam, Germany Inkjet-printed optoelectronic devices – accessing scale and high resolution Felix Hermerschmidt Humboldt-Universität zu Berlin, Germany Carbodicarbene derived extremely electron-rich C(sp³)-C(sp³) bonds Anukul Jana Tata Institute of Fundamental Research Hyderabad, India Luminescent solar concentrator modules fabricated from near-infrared Cu-doped InP/Zn-Cu-In-S/ZnS quantum dots with thicker mid-shell for high absorptivity Jiyong Kim Fraunhofer-Institut für Angewandte Polymerforschung (IAP), Germany

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Solution-processed electronics based on BiOI Vaidehi Lapalikar Technische Universität Dresden, Germany

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Thin films of electron donor-acceptor complexes: characterisation of mixed-crystalline phases and implications for electrical doping Andreas Opitz Humboldt-Universität zu Berlin, Germany Binding quantum dots to amino-functionalized graphene surfaces using amidation reaction Jörg Rappich Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Germany Inelastic electron tunneling (IET) driven optical antennas for ultra-fast optoelectronic signal conversion. Michel Rebmann Universität Tübingen, Germany Investigation of the local physical properties of PEDOT: PSS by atomic force microscopy Matteo Sanviti Universidade da Coruña (UDC), Spain Large area, inkjet printed and dual-coloured perovskite-LEDs Vincent Schröder Helmholtz-Zentrum Berlin, Germany Work function and energy level alignment tuning at Ti 3 C 2 Tx MXene surfaces and interfaces using (metal-)organic donor/acceptor molecules Thorsten Schultz Helmholtz-Zentrum Berlin, Germany Cross-linked naphthalene diimide-based polymer as cathode material for high-performance organic batteries Santosh Sharma National Sun Yat-sen University, Chinese Taipei Effects of bulk and grain boundary properties of Cu(In,Ga)Se 2 photoabsorbers on the device performance of corresponding solar cells Sinju Thomas Helmholtz Zentrum Berlin, Germany

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Evaluation of P3HT:PC61BM with different lateral sizes and contents of graphene oxide (GO) or reduced graphene oxide (rGO) in small and large area solar cells Lucas Tienne Fraunhofer-Institut für Angewandte Polymerforschung (IAP), Germany Novel chalcogenides for photovoltaic applications – crystal growth, structural and physical properties Yvonne Tomm Helmholtz-Zentrum Berlin, Germany Tuning the Surface Electron Accumulation Layer of In 2 O 3 by Adsorption of Molecular Electron Donors and Acceptors Rongbin Wang Humboldt-Universität zu Berlin, Germany Exploring halide perovskites in macroscopic world through microscopic techniques Daniel Abou-Ras Helmholtz-Zentrum Berlin, Germany Understanding Li Metal Anode and Solid-Electrolyte-Interphase (SEI) with Cryogenic Electron Microscopy (cryo-EM) Yaolin Xu Helmholtz-Zentrum Berlin für Materialien und Energie (HZB), Germany Illumination-driven energy level alignment at interfaces between metal halide perovskites and organic semiconductors Fengshuo Zu Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Germany

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Highly conductive PEDOT-based materials for thermoelectric and photovoltaic applications Renaud Demadrille, Magatte N. Gueye, Amélie Schultheiss, Jérôme Faure-Vincent, Stéphanie Pouget, Valid M. Mwalukuku, Alexandre Carella, Jean-Pierre Simonato University of Grenoble, France Pi-conjugated polymers are promising materials for the fabrication of transparent conducting layers in optoelectronics. They have many advantages over inorganic materials, such as low cost, easy deposition by printing techniques and high flexibility [1] . However, their electrical conductivity needs to be improved to meet the requirements of certain applications. In this presentation, we report a simple method for the preparation of poly(3,4-ethylenedioxythiophene) (PEDOT) thin films that show conductivity above 6000 S. cm -1[2-3] . We will show that such an improvement in the conductivity of PEDOT films requires precise control of the water content during the polymerisation step. XRD, HRTEM, synchrotron GIWAXS analyses and conductivity measurements down to 3 K have allowed us to correlate the organisation of these highly conductive polymeric materials to the doping and transport mechanisms. We will show that these PEDOT-based materials have good mechanical properties and remarkably high stability [4] . Finally, we will report on their use in the fabrication of thermoelectric devices [5] , transparent all-polymer heating films [6] and solar cells. References 1. Prog. Mater. Sci., 2020, 100616.

2. Chem. Mater., 2016, 28, 3462-3468. 3. J. Mater. Chem. C, 2020, 8, 17254. 4. ACS Appl. Polym. Mater. 2021, 3, 11, 5942–5949. 5. Mater. Chem. Front., 2020, 4, 2054. 6. ACS Appl. Mater. Interfaces, 2017, 9, 27250-27256.

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Emerging microporous membranes for energy-relevant applications Zhongyi Jiang Tianjin University, China Transport of target molecules and ions from gas and liquid molecular mixtures in energy-relevant applications, lie in the frontier of membrane science and technology. A number of emerging microporous materials, such as covalent organic framework (COF), metal-organic framework (MOF), have exhibited the great potential as building blocks of molecular separation membranes, ion conduction membranes and ionic separation membranes. In this presentation, the concept of organic molecular sieve membranes (OMSMs) will be first introduced with the focus on the precise construction of membrane structures and efficient intensification of membrane processes. The platform chemistries, designing principles, assembly methods for the precise construction of OMSMs are elaborated. Mass transport mechanisms for the process intensification are analyzed based on the interactions between OMSMs and penetrate(s). ‘STEM’ guidelines of OMSMs are highlighted to correlate the precise construction of OMSM structures and efficient intensification of OMSM processes. The major research advances in covalent organic framework membranes in our group will be introduced.

References 1. Wang, H; Wang, M; Jiang, Z. et al. Chem. Soc. Rev., 2021, 50: 5468-5516. 2. He, G.; Zhang, R.; Jiang, Z. et al. Acc. Mater. Res. 2021, 2: 630-643. 3. Wang, M.; Pan, F.; Zhang, Z.; Jiang, Z. et al, Nat. Sustain., 2022, 5(6): 518-526. 4. Shi, B.; Pan, F.; Jiang, Z.et al, Nat. Commun., 2022, 13(1): 6666. 5. Liu, Y.; He, G.; Jiang, Z. et al, Adv. Mater., 2022, 34(24): 2201423. 6. Guo, Z.; Wu, H.; Jiang, Z. et al, Angew. Chem. Int. Ed., 2022, e202210466. 7. Khan, N.; Wu, H.; Jiang, Z. et al, J. Am. Chem. Soc., 2020, 142(31): 13450-13458

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Electronic/ionic, plasmonic and photonic neuromorphic device concepts for artificial neural networks Emil List-Kratochvil Humboldt-Universität zu Berlin, Germany Artificial neural networks (ANN), inspired by biological nervous systems, enable signal processing beyond the capabilities of von Neumann computer architectures. Through dynamically adapting the connectivity (synaptic weights) in individual devices and by applying learning algorithms ANNs can offer in memory and tensor computing capabilities. Yet, to fully unleash the potential of hardware ANNs there is still a need for neuromorphic device concepts, which properly emulate all necessary synaptic functions adequately and allow for an easy integration into large scale hardware ANNs. In this contribution we will demonstrate novel electronic/ionic, plasmonic and photonic neuromorphic single device concepts and integration into photonic ANNs using hybrid material systems.

This work was supported by the Deutsche Forschungsgemeinschaft through the CRC 951.

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Colloidal synthesis approach for energy materials Yan Lu Helmholtz-Zentrum Berlin für Materialien und Energie, Germany

Colloidal route is one of the favored ways toward cost-effective large-scale production of various nanostructures [1] . In our study, different types of nanoparticles have been designed and synthesized via colloidal approach, which can be applied as electrode materials for various supercapacitor [2] and battery systems. [3,4] For example, multifunctional Ti 4 O 7 particles with interconnected-pores structure have been synthesized by using porous PS-P2VP particles as soft template [5] . In order to improve the conductivity of the electrode, a thin layer of carbon has been coated on the Ti 4 O 7 surface without destroying its porous structure. The porous Ti 4 O 7 particles as well as carbon-coated Ti 4 O 7 particles show significantly improved electrochemical performances as cathode material for Li-S batteries as compared with that of TiO 2 particles. The scale-up of the synthesis of cathode material with well-defined structure is one of the main challenges in battery manufacture. More recently, we have managed to upscale the synthesis of hollow Ti 4 O 7 nanoparticles using spherical polyelectrolyte brushes as the template by using the minipilot reactor (5 L) . The obtained Ti 4 O 7 hollow particles have been successfully used as cathode materials for Li-S batteries in the form of pouch cells [6] . More recently, we have also extended this approach to complex hybrid carbon nanostructures with potential use in electrochemical energy storage and conversion [7] . References 1. W. Li, G. Zheng, Y. Yang, Z.W. Seh, N. Liu, Y. Cui, PNAS 2013 , 110, 7148. 2. T. Quan, N. Goubard-Bretesché, E. Härk, Z. Kochovski, S. Mei, N. Pinna, M. Ballauff, Y. Lu, Chem. Eur. J. 2019 , 25, 4757- 4766. 3. D. Xie, S. Mei, Y. Xu, T. Quan, E. Hark, Z. Kochovski, Y. Lu, ChemSusChem 2021 , 14, 1404-1413. 4. T. Quan, Y. Xu, M. Tovar, N. Goubard-Bretesché, Z. Li, Z. Kochovski, H. Kirmse, K. Skrodczky, S. Mei, H. Yu, D. Abou-Ras, M. Wagemaker, Y. Lu, Batteries & Supercaps 2020 , 3, 1-11. 5. S. Mei, C. J. Jafta, I. Lauermann, Q. Ran, M. Kärgell, M. Ballauff, Y. Lu, Adv. Funct. Mater. 2017 , 1701176. 6. S. Mei, A. Siebert, Y. Xu, T. Quan, R. Garcia-Diez, M. Bär, P. Härtel, T. Abendroth, S. Dörfler, S. Kaskel, Y. Lu, Batteries & Supercaps 2022 , e202100398. 7. 2. D. Xie, Y. Xu, Y. Wang, X. Pan, E. Härk, Z. Kochovski, A. Eljarrat, J. Müller, C. T. Koch, J. Yuan, Y. Lu, ACS Nano 2022 , 16, 10554–10565.

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Phases, polytypes and polymorphs: how to make what you want in nanocrystal synthesis Janet Macdonald 1,2 , Jeremy R. Espano 1 , Andrey A. Shults 1,2 , Alexandra C. Koziel 1,2 , Danielle N. Penk 1,2 , Antony R. Peng 1,2 , Eric Ho 1,2 , Emma J. Endres 1,2 , Ahmed Y. Nuryie 3 , Guanyu Lu 2,4 , Joshua D Caldwell 2,4 1 Department of Chemistry, Vanderbilt University, Nashville, USA 2 Vanderbilt Institute for Nanoscale Science and Engineering, Nashville, USA 3 Department of Chemistry, The Pennsylvania State University, Abington, Pennsylvania, USA 4 Department of Mechanical Engineering, Vanderbilt University, Nashville, USA When nature provides multiple options of compound materials, how and why does one crystalline phase form over another in a synthesis? The literature is rife with phenomenological observations of synthetic conditions that give certain phases. In truth, as scientists, we do not have the synthetic tool kit to a priori imagine a synthesis that selects for one natural geological phase over another, nor rationally tweak a “failed” reaction to achieve a goal phase. Without this knowledge, it is very hard to imagine we can synthesize, study, and exploit the full potential of the periodic table in crystalline materials. Two projects aimed at creating such a tool kit will be presented. A library of substituted thioureas reagents were used as a way to study isolate the effect of the kinetics of the release of sulfur on the phase of iron and cobalt sulfides. These studies illuminated the paths how the metal sulfides transform into each other. Specifically, the anion packing pattern of ccp or hcp in the nucleated phase is the key determining factor of the family of phases produced through further sulfur inclusion. The knowledge of the relationships between the phases was used to identify conditions to selectively synthesize phase pure samples of many of the cobalt and iron sulfides. One of the main challenged with nanocrystal synthesis is we don't often know what is happening at the molecular level. Phase and polytype control is very conditions dependent. In the second part I will describe how we are using 1 H and 77 Se NMR to peer into the "black box," and finding out exactly why small changes in reagent, ligand identify, ligand concentration, and solvent are influencing phase. References 1. Espano, JR; Macdonald JE " Phase Control in the Synthesis of Iron Sulfide" Journal of the American Chemical Society , 2023, accepted. Shults, AA; Lu, G; Caldwell, JD, Macdonald JE " Role of Carboxylates in the Phase Determination of Metal Sulfide Nanoparticle" Nanoscale Horizons , 2023, accepted Penk, DN; Endres, EJ; Nuriye, AY; Macdonald JE "Dependence of Transition-Metal Telluride Phases on Metal Precursor Reactivity and Mechanistic Implications" Inorganic Chemistry, 2023, 62, 9, 3947-3956. 2. Koziel, A; Goldfarb, R; Endres, E; Macdonald, JE"Molecular Decomposition Routes of Diaryl Diselenide Precursors in Relation to the Phase Determination of Copper Selenides" Inorganic Chemistry, 2022, 61, 14673-1683 Ho, EA; Peng, AR; Macdonald JE “Alkyl Selenol Reactivity with Common Solvents and Ligands: Influences on Phase Control in Nanocrystal Synthesis” Nanoscale , 2021, 22, (14), 76-85.

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Exploring the solar cell materials landscape with NOMAD Jose Marquez Prieto Humboldt University of Berlin, Germany The evolution of new solar cell technologies is often slow-paced, typically requiring decades to surpass the 20% power conversion efficiency barrier for commercial viability. Given the almost infinite number of potential chemical compositions for new absorber layer materials and the limitless possibilities of device architectures, navigating this material space becomes an unattainable task without employing data science tools. This talk will introduce the NOMAD Laboratory (https://nomad-lab.eu), a platform supported by the NFDI consortium FAIRmat (https://fairmat-nfdi.eu), designed to meet these challenges head-on by making materials science data Findable, Accessible, Interoperable, and Reusable (FAIR). I will illustrate the ongoing evolution of the NOMAD infrastructure in supporting solar cell research, featuring an app developed to visualize and search an expansive and AI-ready solar cell dataset. The platform also includes an adaptable electronic lab notebook (ELN) that can be tailored by research labs to facilitate AI-ready data/metadata capture, transfer, and processing within a FAIR database context. Building upon the public data available in NOMAD, enriched by the perovskite database project, I will discuss the evolution of the materials used as transport layers in perovskite solar cells based on network analysis. This study highlights the need for our current scientific publication culture to be supplemented with structured data artifacts. These additional resources can enable scientists to better leverage the vast knowledge presented in the rapidly expanding body of publications in their discipline, which is currently an overwhelming resource to navigate at this scale.

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Semi-paracrystallinity in semiconducting polymers for photovoltaics Jaime Martin University of La Coruña, Spain

Precise determination of structural organization of semiconducting polymers is of paramount importance for the further development of these materials in organic electronic technologies, as solid-state microstructure and optoelectronic properties are highly interlinked. Yet, prior characterization of some of the best-performing materials for transistor and photovoltaic applications often resulted in conundrums in which X-ray scattering and microscopy yielded seemingly contradicting results and. In this presentation I will discuss that the paradox above stems from the fact the microstructure of these materials does not seem to fit with stablished structural models for polymers, i.e. the amorphous, semi-crystalline and paracrystalline models, and, hence, these polymers require the introduction of a new structural organization model. Thus, we introduced the semi-paracrystallinity. The semi-paracrystalline model establishes that the microstructure of these materials contains a dense array of small paracrystalline domains and more disordered regions. Thus, unlike other models, the overall structural order relies on two parameters: the novel concept of degree of paracrystallinity (i.e., paracrystalline volume/mass fraction) and the lattice distortion parameter of paracrystalline domains ( g -parameter from X-ray scattering). I will show that charge carrier transport in semi-paracrystalline materials is particularly sensitive to the interconnection of paracrystalline domains. Because the semi-paracrystalline microstructure seems to be a common feature among many semiconducting polymers, these results can have profound implications in the broad organic electronics arena, where device operation models and device optimization protocols must now include the semi- paracrystalline organization.

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Soft PhotoElectroChemical systems for solar fuels Erin Ratcliff University of Arizona, USA

Highly scalable, durable π-conjugated polymer materials provide control over local environments afforded through synthesis, long-lived charge carrier lifetimes, and flexible, low-cost, and scalable thin film formats which circumvent the shortcomings of inorganic materials (surface states, grain boundaries, challenges in processing, and mechanically unstable platforms). The Center for Soft PhotoElectroChemical Systems (SPECS) is an Energy Frontier Research Center focused on the basic science questions that underpin the development of low-cost, robust energy conversion and energy storage technologies based on new organic polymer (plastic) electronic materials. These materials are predicted to fill a critical position in the U.S. energy portfolio, providing for next- generation fuel-forming platforms (energy conversion) and batteries (energy storage) that cannot currently be achieved with conventional (hard) inorganic materials. The realization of all-organic semiconductor systems that capture light energy and convert it into chemical energy requires a detailed understanding of structure-property relationships governing the interconnected dynamics of photo-generation, transport, and electron transfer across multiple interfaces. Dark electrochemical processes must be understood before increasing the complexity via light-matter interactions. This talk will focus on increasing complex, multiple interface platforms, towards the goal of photons-to-electrons-to-molecules energy conversion processes. A number of emerging in situ/operando spectroelectrochemical and scanning electrochemical cell microscopy approaches will be discussed for this exciting new area of energy conversion. Examples of operando x-ray photoelectron spectroscopy will also be discussed for chemically-resolved electrochemical measurements (CREM).

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An enabling thin-film deposition technique for hybrid optoelectronic devices Adrienne Stiff-Roberts Duke University, USA Hybrid perovskites with the ability to control spin, charge, and light could establish a new semiconductor technology that is especially useful for optoelectronic devices. While CH 3 NH 3 PbI 3 (methylammonium lead triiodide, or MAPbI) easily can be solution-processed, the same is not true for hybrid perovskites comprising larger, more complex organic molecules that have incompatible solubility with metal halides. Alternatively, vapor-phase deposition of organic precursors can introduce degradation and make stoichiometric deposition with inorganic precursors more difficult. However, resonant infrared, matrix-assisted pulsed laser evaporation (RIR-MAPLE), a versatile thin-film deposition technique that features aspects of both solution-based and vapor-phase deposition, enables a wide variety of hybrid perovskite thin films that can be difficult to achieve otherwise. This talk will review the development of RIR-MAPLE growth of hybrid perovskite thin films, demonstrating application to 3D MAPbI and 2D hybrid perovskites (such as oligothiophene- and phenethylammonium-based metal halide perovskites).

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Crystal structures of molecular semiconductors: control and prediction Kazuo Takimiya Tohoku University and RIKEN CEMS, N.A., Japan The crystal structure critically affects the carrier transport properties of molecular semiconductors. However, it is vertically impossible to predict the crystal structures of molecular semiconductors, which has been one of the obstacles to developing high-performance molecular semiconductors. Thus, it is highly desirable to develop practical methods to accurately predict the crystal structures of given molecular semiconductors before synthesizing molecules, which is the most time-consuming and labor-intensive process. To tackle this, we are approaching the issue both from the experimental and computational points of view. From the experimental viewpoint, we found the effect of regio-selective methylthiolation to "manipulate" crystal structures of molecular semiconductors. The organic semiconductors with the herringbone crystal structure, like acenes and thienoacenes, crystalize into the rubrene-like pitched pi-stacking structure by methylthiolation at the particular position [1] . On the other hand, peri -condensed polycyclic aromatic hydrocarbons (PAHs), such as pyrene and perylene, upon regio-selective methylthiolation, crystalize into the brickwork structures, enabling ultrahigh mobility of 30 cm 2 V –1 s –1 in 1,3,6,8-tetrakis(methylthio)pyrene based field-effect transistors [2] . In our computational approach, on the other hand, we developed a simple and intuitive way to simulate the brickwork crystal structures of methylthiolated peri -condensed PAHs. Using the method, we can simulate the crystal structures of a range of methylthiolated peri -condensed PAHs, leading to a new high-performance molecular semiconductor showing mobility of up to 30 cm 2 V –1 s –1 [3] . With these experimental and computational results, we will discuss the possibility of molecular design by crystal structure simulations. References 1. C. Wang, K. Takimiya et al ., Chem. Sci . 2020 , 11 , 1573; K. Kanazawa, K. Bulgarevich, K. Kawabata, K. Takimiya, Cryst. Growth Des ., in press (DOI: 10.1021/acs.cgd.3c00525). 2. K. Takimiya, K. Bulgarevich, et al ., Adv. Mater . 2021 , 33 , 2102914. 3. K. Bulgarevich, S. Horiuchi, K. Takimiya, Adv. Mater. , in press (DOI: 10.1002/adma.202305548).

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FAIRification of research data management in halide perovskite photovoltaics Eva Unger Lund University, Sweden

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Vapor deposition of metal halide perovskites – photovoltaics and beyond Yana Vayznof Technical University of Dresden, Germany In recent years, remarkable progress has been made in the field of perovskite solar cells, resulting in power conversion efficiencies (PCE) of 26%. While the vast majority of research efforts are dedicated to their processing from solution, metal halide perovskites can also be deposited by thermal evaporation. It is a solvent-free, scalable method of high industrial relevance offering high throughput, homogeneity, material economy, safety, yield and controllability. In this talk, I will present a range of applications in which the utilization of vapor deposited perovskites offers clear advantages to their processing from solution. For example, I will introduce a new concept for photovoltaic devices that exploits the polymorphism of perovskite materials to form a phase heterojunction solar cell. The concept relies on the fabrication of a β-CsPbI 3 bottom layer by solution processing and a top γ-CsPbI 3 layer by thermal evaporation. [1,2] I will also introduce an outlook to utilizing vapor deposited perovskites in applications beyond photovoltaics.

References 1. Z. Zhang et al., Adv. Energy Mater. 2021 , 11 (29), 2100299. 2. R. Ji et al. Nature Energy 2022 , 7, 1170.

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Modifications of nanostructured TiO 2 for efficient photocatalytic and photoelectrochemical green hydrogen production Ewa Wierzbicka 1 , Chengxu Shen 2 , Thorsten Schultz 3,4 , Karolina Syrek 5 , 2 Institut fur Chemie and IRIS Adlershof, Humboldt-Universitat zu Berlin, Germany 3 Institut fur Physik and IRIS Adlershof, Humboldt-Universitat zu Berlin, Germany 4 Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Berlin, Germany 5 Faculty of Chemistry, Jagiellonian University in Krakow, Poland Hydrogen is the most promising substitute for classic fossil fuels. It is an energy carrier that could show a zero- carbon footprint in ideal production and usage conditions. Developing new technologies for clean and sustainable hydrogen production is necessary for response to the growing demand for hydrogen in newly developing sectors such as transportation. Grzegorz Sulka 5 , Norbert Koch 3,4 , Nicola Pinna 2 1 Military University of Technology, Warsaw, Poland One strategy of sustainable hydrogen generation is based on photosensitive materials that can split water into hydrogen and oxygen using solar radiation. Since 1972, when Fujishima and Honda discovered the phenomenon of water photolysis from TiO 2 , it has become the benchmark semiconductor material tested for photocatalysis (PC) and photoelectrocatalysis (PEC). After these years, the PC/PEC hydrogen evolution from water still needs to become more efficient to meet the economic criteria of commercialization. Therefore, further modifications are necessary to improve the material's performance. TiO2 can form various nanostructures, such as nanopowders and nanotubes/nanoporous arrays, with much higher surface area than bulk materials. Nanostructurization of the TiO 2 -based material itself strongly increases PC/PEC performances. Moreover, such materials show great potential for further modifications. On the one hand, the most efficient and frequently used approach to TiO 2 modification is coupling it with noble metal cocatalysts such as Pt, Ag, and Au [1,2] . This modification brings much higher PEC and PC process efficiencies assigned to several effects, such as Schottky barrier formation, co-catalytic properties into hydrogen absorption, or surface plasmon resonance. The processes that might occur at the metal-semiconductor interface are complex depending on the type of metal used in heterojunction. On the other hand, noble-metal-free modification strategies, such as sensitization with other semiconductors [3] or so-called material self-doping, are becoming increasingly popular [4,5] . Here will be shown how adequately designed modification of nanostructured titania can improve PC/PEC water- splitting performance by creating suitable electronic pathways to enhance spatial separation of photogenerated charge carriers, improve reaction kinetics at the material/electrolyte interface, or extending absorption into visible light range. References 1. E. Wierzbicka, T. Schultz, K. Syrek, G.D. Sulka, N. Koch, N. Pinna, Mater. Horiz. 9, 2797-2808 (2022). 2. E, Wierzbicka, et al. ACS Appl. Energy Mater. 2, 8399–8404 (2019). 3. C. Shen, E. Wierzbicka*, T. Schultz, R. Wang, N. Koch, N. Pinna*, Adv. Mater. Interfaces 9, 2200643 (2022).

4. E. Wierzbicka, et al. J. Mater. Chem. A 9, 1168-1179 (2021). 5. E, Wierzbicka, et al. ChemSusChem 12, 1900-1905 (2019).

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The role of grain boundaries and dislocations in various solar-cell materials on the corresponding device performance Daniel Abou-Ras 1, Sinju Thomas 1 , Dan Wargulski 1 , Jiro Nishinaga 2 1 Helmholtz-Zentrum Berlin, Germany 2 National Institute of Advanced Industrial Science and Technology, Japan While currently, the solar-module market is dominated by silicon-wafer-based photovoltaics, its potential for improvements in terms of the cost-performance ratio is limited. Thin-film solar cells exhibit in this respect much brighter perspectives and in addition, also the possibility for roll-to-roll production using flexible substrates. In the solar-cell stacks suitable for the mass production of thin-film solar modules, all functional layers are polycrystalline. Therefore, the role of grain boundaries and dislocations on the device performance has always been a matter of concern in the research and development of thin-film solar cells. The present work gives an overview of the current knowledge on this topic. Results from the analyses of microscopic structure-property relationships mainly by electron microscopy are presented. It will be shown that grain boundaries are always locations of enhanced nonradiative recombination in various solar absorber layers, and correspondingly, lead to a substantial decrease in open-circuit voltage of the solar cells. On the other hand, while dislocations contribute to enhanced nonradiative recombination in various solar-cell materials, these line defects exhibit similar recombination behaviors as the surrounding bulk material in Cu(In,Ga)Se 2 thin films. References 1. D. Abou-Ras, U. Bloeck, S. Caicedo-Dávila, A. Eljarrat, H. Funk, A. Hammud, S. Thomas, D.R. Wargulski, T. Lunkenbein, C.T. Koch, Correlative microscopy and monitoring of segregation processes in optoelectronic semiconductor materials and devices, J. Appl. Phys. 133, 121101 (2023), doi: 10.1063/5.0138952. 2. D. Abou-Ras, A. Nikolaeva, M. Krause, L. Korte, H. Stange, R. Mainz, E. Simsek Sanli, P.A. van Aken, T. Sugaya, J. Nishinaga, Optoelectronic inactivity of dislocations in Cu(In,Ga)Se2 thin films, phys. stat. sol. (RRL) 15 (2021) 2100042, doi: 10.1002/pssr.202100042. 3. M. Krause, A. Nikolaeva, M. Maiberg, P. Jackson, D. Hariskos, W. Witte, J.A. Márquez, S. Levcenco, T. Unold, R. Scheer, D. Abou-Ras, Microscopic origins of performance losses in highly efficient Cu(In,Ga)Se2 thin-film solar cells, Nature Comm. 11 (2020), doi: 10.1038/s41467-020-17507-8. 4. D. Abou-Ras, S.S. Schmidt, N. Schäfer, J. Kavalakkatt, T. Rissom, T. Unold, R. Mainz, A. Weber, T. Kirchartz, E. Simsek Sanli, P.A. van Aken, Q.M. Ramasse, H.-J. Kleebe, D. Azulay, I. Balberg, O. Millo, O. Cojocaru-Mirédin, D. Barragan-Yani, K. Albe, J. Haarstrich, C. Ronning, Compositional and electrical properties of line and planar defects in Cu(In,Ga)Se2 thin films for solar cells - a review, Phys. Stat. Sol. (RRL) 10 (2016) 363-375, doi: 10.1002/pssr.201510440.

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Watching Ternary Oxides with Dual Eyes: two-colour xes studies of chemical transformations & electronic structure in ferric pseudobrookite (Fe 2 TiO 5 ) photoanodes Devi Prasad Adiyeri Saseendran 1 , Sergey Peredkov 2 , Carlos A. Triana 1 , Daniel Abbott 3 , Victor Mougel 3 , Serena DeBeer 2 , Greta R. Patzke 1 1 Department of Chemistry, University of Zurich, Switzerland, 2 Department of Inorganic Spectroscopy, Max Planck Institute for Chemical Energy Conversion Germany, 3 Department of Chemistry and Applied Biosciences, Switzerland The design of highly efficient, robust, and green water oxidizing catalysts is one of the most critical challenges in sustainable energy research. [1] Solar-assisted photo-electrocatalytic (PEC) water splitting has emerged as a promising approach to producing clean chemical fuels and energy resources. An ideal photo-electrode material encompasses a suitable energy bandgap for efficient sunlight absorption, electrical conductivity, chemical stability, and non-toxicity. [2] α-Fe 2 O 3 had gained considerable interest in the field due to its suitable bandgap (1.9-2.2 eV) and earth abundance. Doping α-Fe 2 O 3 with Ti 4+ , and Zr 4+ had been found to increase its carrier conductivity, thereby improving the PEC performance. [3] In this regard, ternary oxide materials have emerged as potential candidates for photoanode materials, as they provide diverse strategies for tuning the composition and electronic structure of photoanode materials compared to their binary counterparts. [4] Among these, the ferric pseudobrookite: Fe 2 TiO 5 has received significant attention owing to its high thermodynamic phase stability, phase stability in a wide pH range, and suitable bandgap (1.9- 2.1 eV) for efficient solar light absorption. [5–7] We report the fabrication of Fe 2 TiO 5 inverse opals photoanodes which have shown improved photo-current density under solar light irradiation. Understanding multiple metal active sites concomitantly, is of utmost importance to unravel the synergistic role of metal centers in driving the activation process. In this regard, herein we demonstrate the use of two-colour X-ray Emission Spectroscopy (XES) in identifying the intermediates and electronic structure changes involved in solar water oxidation catalyzed by Fe 2 TiO 5 photoanodes, by simultaneously tracking Fe and Ti sites under operational PEC conditions. In situ XES studies indicated that the Ti sites act as oxo-coordination sites whereas the Fe site behaves as a redox regulator. Post-catalytic XAS and XPS investigations also confirms change in local coordination at the Ti center, suggesting its active role in driving the O-O bond formation. References 1. B. You, Y. Sun, Acc Chem Res 2018 , 51 , 1571–1580. 2. Gurudayal, P. S. Bassi, T. Sritharan, L. H. Wong, J Phys D Appl Phys 2018 , 51 , 473002. 3. D. K. Lee, D. Lee, M. A. Lumley, K. S. Choi, Chem Soc Rev 2019 , 48 , 2126–2157. 4. Q. Liu, J. He, T. Yao, Z. Sun, W. Cheng, S. He, Y. Xie, Y. Peng, H. Cheng, Y. Sun, Y. Jiang, F. Hu, Z. Xie, W. Yan, Z. Pan, Z. Wu, S. Wei, Nat Commun 2014 , 5 , 1–7. 5. E. Courtin, G. Baldinozzi, M. T. Sougrati, L. Stievano, C. Sanchez, C. Laberty-Robert, J Mater Chem A Mater 2014 , 2 , 6567–6577. 6. M. Osada, K. Nishio, K. Lee, M. Colletta, B. H. Goodge, W. J. Kim, L. F. Kourkoutis, H. Y. Hwang, Y. Hikita, ACS Appl Energy Mater 2021 , 4 , 2098–2106.

P02

The influence of gas cluster ion beam surface etching on the chemical and electronic structure of perovskite Emily Albert 1 , Dongguen Shin 1 , Patrick Amsalem 1 , Fengshuo Zu 1 , Norbert Koch 1,2 1 Humboldt-Universität zu Berlin, Germany, 2 Helmholz-Zentrum Berlin, Berlin, Germany Understanding the interface electronic properties in halide perovskites (HaP) - based optoelectronic devices is of major importance to optimize their efficiency and functionality. However, reaching the substrate / HaP thin film interface is challenging and can eventually be achieved by physical etching of the typically 500 nm thick thin films. While standard depth profiling with argon ions results in massive damage of the HaP, we investigated the impact of gas cluster ion beams (GCIB) on methylammonium lead iodine (MAPbI 3 ) and characterized the etched surface by photoelectron spectroscopy and atomic force microscopy. We analyzed the evolution of MAPbI 3 thin films (450 - 500 nm thick) electronic and chemical properties as a function of sputtering time and kinetic energy per argon atom, using selected settings of 10 keV/˜3000 and 5 keV/˜6000 Ar atoms per cluster. The first setting showed the formation of PbI 2 and Pb 0 after just 1h of exposure as well as a shift in the secondary electron cut off (SECO) and valence band (VB) onset. After 33h, the film showed no perovskite like properties anymore with a remaining inhomogeneous film of ˜100 nm thickness. The second setting showed neither chemical degradation nor a shift in the SECO after 1h of exposure. Following 13h, evidence of the formation of PbI 2 as well as Pb 0 appeared together with a shift in the SECO and VB onset. After 32h, the film still exhibited a thickness of ˜400 nm. Consequently, the utilized settings showed that there is a trade off between the etching depth and the degradation of the perovskite film. While gas cluster ion beam sputtering seems not to be suitable for the depth profiling of MAPbI 3 , the second setting with 5keV/˜6000 argon atoms per cluster could potentially be utilized for cleaning the perovskite surface, in the view of fundamental surface studies.

P05

Core-shell phase segregation in Nanocrystals: A pathway for unlocking new internal quantum yield efficiencies Fernando Arteaga Cardona 1 , Eduard Madirov 1 , Dmitry Busko 1 , Radian Popescu 3 , Noopur Jain 4,5 , Sara Bals 4,5 , Sandra Van Aert 4,5 , Bryce S. Richards 1,2 , and Damien Hudry 1 1 KIT-IMT, Germany

2 LTI, Karlsruhe Institute of Technology, Karlsruhe, Germany 3 LEM, Karlsruhe Institute of Technology, Karlsruhe, Germany 4 EMAT, University of Antwerp, Antwerp, Belgium 5 NANOlab Center of Excellence, University of Antwerp, Antwerp, Belgium

Improving the quantum yield of lanthanide-based nanocrystals is crucial for unlocking the full potential of various applications such as bioimaging, biolabeling, anti-counterfeiting, and energy harvesting. However, achieving high quantum yields in nanocrystals presents a significant challenge due to multiple factors that can dampen the emitted energy. These factors include surface quenching, dangling bonds, concentration quenching. One of the most efficient and widely recognized strategies for mitigating the detrimental effects of luminescent quenchers involves the growth of an optically inert shell with the same chemical composition as the luminescent host (homogeneous shell) without the luminescent active centers. However, this approach assumes that the optically active core remains unaffected by the post-synthesis process required to grow the optically inert shell. Recent findings have challenged this assumption, revealing that the integrity of the core is compromised in the majority of the cases, resulting in an intermixed phase that alters interatomic distances, local concentrations, and thus energy migration pathways. Consequently, it becomes challenging to determine the optimal ratio between sensitizers and emitters, preventing to reach high photoluminescence quantum yields. In this study, we present evidence that growing an optically inert heterogeneous shell, instead of a homogeneous one, successfully achieves phase segregation between the luminescent active core and the protective inert shell. The establishment of a genuine core-shell structure significantly enhances the internal downshifting photoluminescence quantum yield (DSPLQY) of lanthanide-based luminescent materials. For samples co-doped with Tm, the heterogeneous shell improved the DSPLQY in the 1,800 nm emission from 1% to 7%. In the case of samples co-doped with Er, the DSPLQY of the 1,550 nm emission improved from 9% to 30%. Furthermore, when Er and Ce were used together, the DSPLQY increased from 26% to 50%. This improvement can be attributed to various factors, including enhanced protection against surface quenching by confining absorbed energy exclusively within the core region. We believe that our results of achieving a well-proven phase segregation between the core and the shell and its heavy impact in the DSPLQY will help to pave the way for the realization of promising applications associated with lanthanide-based nanocrystals.

P07

Electrochemical and structural study on a FEIII-ionic liquid redox electrolyte Christian Balischewski 1 , Biswajit Bhattacharyya 1 , Josh Bailey 2 , Jiyong Kim 3 , Shashank Gahlaut 1 , Yann Garcia 4 , Eric Sperlich 1 , Christina Günter 5 , and Andreas Taubert 1 1 University of Potsdam, Germany, 2 Queen’s University Belfast, BT7 1NN, UK 3 Fraunhofer Institute of Applied Polymer Research (IAP) Germany Ionic Liquids (ILs) are generally understood as salts with melting points below 100°C, which are easy to handle due to their non-flammability and non-volatility. They also exhibit high thermal and electrochemical stabilities with high ionic conductivities. Their physical properties can be altered to fit a specific purpose by changing (parts of) the ions, which means they can be regarded as “task-specific materials”. Introducing metals into ILs can further change the individual properties by inducing new optical or electrical mechanisms and qualities. Furthermore, metal-containing ILs (also called MILs) are currently investigated as precursor materials for syntheses of different metal compounds, such as chalcogenides or perovskites. Due to these qualities, MILs are therefore studied as promising candidates for the synthesis of active energy materials and direct use in energy devices, such as batteries and sensors. 1 In the last decade, due to the increasing cost of resources and severe impact on the environment, a growing focus has been put on new energy production and storage technologies with sustainable material development. In this regard MILs can contribute to both aspects like the transition from using fossil fuels to renewable energy sources with novel design of energy harvesting molecules and switching from rare and expensive materials to more cost-efficient, environmentally friendly and readily available systems for the fabrication of energy storage systems. 4 Institute of Condensed Matter and Nanosciences, Belgium 5 Institute of Geosciences, University of Potsdam, Germany In this study we are presenting a Fe III -based MIL for the direct use in energy devices as an electrolyte. The MIL (BuPy)[FeCl 4 ] has been synthesized and its structural properties are analyzed using single crystal X-ray analysis, X-ray powder diffraction, Infrared spectroscopy, as well as X-ray photoelectron spectroscopy and Mössbauer spectroscopy, showing that the compound consists of one N -butylpyridinium cation and one [Fe III Cl 4 ] - anion. The anions organize themselves in tilted anion chains, which is a reason for the low melting temperature of just 35°C. Additionally Cyclic voltammetry in MeCN and water was used to identify redox processes. In MeCN the system shows a reversible redox couplet with E 1/2 =-0.419V vs. Fc + /Fc with ΔE p =87mV. This can be attributed to the redox processes between [Fe II Cl 4 ] 2- and [Fe III Cl 4 ] - . 2 This reversible process indicates that (BuPy)[FeCl 4 ] is a promising candidate for an electrolyte application in the growing field of Fe-based redox flow batteries (RFBs). References 1. Y. Kim, et al . J. Chem. Phys. 2018. 148 (19): 193818. DOI: 10.1063/1.4991622 M. Yamagata, et al . Electrochimica Acta. 2007. 52 (9): 3317-3322. DOI: 10.1016/j.electacta.2006.10.008

P08

Excitonics of Squaraine Dunes Frank Balzer 1 , Marvin F. Schumacher 2 , Arne Lützen 2 , Manuela Schiek 3 1 University of Southern Denmark, Centre for Photonics Engineering, Denmark 2 Kekulé Insitute of Organic Chemistry and Biochemistry, Germany 3 LIOS &; ZONA, Johannes Kepler University, Austria

Squaraine thin films are gaining significant attention in the field of optoelectronics due to their unique, anisotropic optical properties. They have a high photostability and exhibit strong absorption in the visible and near-infrared region, making them ideal for applications in photovoltaics and photodetectors. The prototypical squaraine SQIB, Fig. 1(a) , condenses into two different polymorphs, both with different optical, electronic, and mechanical properties. The formation of periodic dunes can be induced during crystallization, Fig. 1(b,c) . For the orthorhombic polymorph [1] , the real parts of the dielectric tensor become strongly negative [2] , allowing field enhancement at sharp objects such as the tips of the dunes or at narrow cracks. Raman microscopy together with polarized absorption spectro- microscopy and nanomechanical characterization paint a full picture of the excitonic coupling within the dunes.

Fig. 1. (a) SQIB. (b) AFM image of monoclinic SQIB thin film dunes. A Fourier-transform, inset in (b), together with a cross section (c) along the green line demonstrates their spatial periodicity. References 1. F. Balzer, T. Breuer, G. Witte, M. Schiek, Template and Temperature-Controlled Polymorph Formation in Squaraine Thin Films, Langmuir 38 (2022) 9266. 2. S. Funke, M. Duwe, F. Balzer, P.H. Thiesen, K. Hingerl, M. Schiek, Determining the Dielectric Tensor of Microtextured Organic Thin Films by Imaging Mueller Matrix Ellipsometry, J. Phys. Chem. Lett. 12 (2021) 3053.

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