Solar arrays are the main power source in space. Conventionally they are composed of stiff backing structures and brittle PV cells. While the power demands of space missions are increasing, e.g. for electric propulsion, the increase of efficiency of the solar cells itself is limited. New developments make use of flexible and semi-flexible solar array designs in order to achieve higher power/mass and power/volume ratios. An example is a two-dimensional deployment of solar arrays in order to increase the deployed area as instigated in DLR’s GoSolAr project. Such deployment strategies can be combined either with conventional photovoltaics, also using thinned wafer technology, or with thin-film technologies that are truly flexible. Development of such technology involves also deployment testing and testing of materials under the specific radiation environment that is present in space. In this talk I would like to give an overview about the development aspects, showing how we try to go beyond conventional array designs but still using photovoltaic solar cells.

Patric Seefeldt is a 39 years old mechanical engineer with a diploma (RWTH Aachen 2010) and a PhD (University of Bremen 2018). As deputy head of the Mechanics and Thermal Systems Department (since 2016) and head of the Material Aging Group (since 2019) at DLRs’ Institute of Space Systems, he is pursuing research in the field of innovative applications of new materials for space technologies.

Polyimide (PI) represents a class of important materials in various space applications due to their high thermal resistance, good dielectric and mechanical properties, which make PIs good candidates for thermal control materials, electrical insulating coatings, solar cell substrates, and other protecting components on spacecraft. However, when the standard PIs are exposed to the severe space environment, they are subject to degradation of the thermal optical property through oxidation and etching by atomic oxygen (AO) in low Earth orbit (LEO). AO is created by the dissociation of molecular oxygen caused by solar ultraviolet radiation at wavelengths below 243 nm. Such property degradation has been a serious impediment for application of PIs for spacecraft. Therefore, the protection of PIs from long-term AO erosion has become one of the most important issues to be addressed in the design and manufacturing of spacecraft components operating in LEO. The PI films and composites have been most widely studied for the protection purpose from AO erosion. However, few works on the AO erosion and protection research on the PI fibers or fabrics have been reported up to now although PI fibers have increasingly attracted attention in space application. In this talk, I would like to present the most recent work in our lab on the AO resistance of PI nanofibrous membranes (NFMs) incorporated with POSS.

Dr. Wu Bohan has been working as a senior engineer at Beijing Institute of Spacecraft Environment Engineering since 2014. Her expertise is ground-based space environmental simulation, space material evaluation, and development of AO protection materials. She worked as a Postdoctoral Research Associate at the University of Basel, Switzerland and at Montana State University, USA. She got her PhD in Physical Chemistry at the University of Nottingham, UK. She has experience in the general field of physical chemistry with specialization in cluster science, molecular dynamics, high-resolution spectroscopy, and materials science.

In this talk I will give an overview of some of the challenges related to the radiation testing of materials for space applications, describing some of the test facilities and techniques, showing results of investigations our group in ESTEC has performed as well as discussing prospective materials technologies which could be utilized for radiation energy conversion for future space missions.

Dr. Adrian Tighe is a senior materials engineer working for the European Space Agency,  where he leads the environmental testing group within the Materials Physics and Chemistry Section, utilizing an array of advanced state-of-the-art vacuum facilities to simulate the effects of the space environment on materials.

Radiotherapy is a trade-off between tumour control and unwanted side effects in healthy tissue. Both radiation effects depend on the absorbed dose, i.e. energy imparted per mass. Due to proliferation, cancer cells are susceptible to radiation damage. This opens the so-called therapeutic window, i.e. a dose range where treatment efficacy exceeds the risk of side effects, whose width is fixed by biological factors. High-Z nanoparticles offer the prospective to selectively enhance energy deposition in tumours while sparing healthy tissue.

Hans Rabus graduated in surface science at Freie Universität Berlin and then worked for 27 years in radiation metrology at PTB, Germany’s National Metrology Institute, were he was leading for 11 years the department “Radiation Effects” in the Ionizing Radiation division.

Wide bandgap metal halide perovskites are promising candidates to pair with low bandgap silicon, copper indium gallium diselenide, or perovskite photovoltaics for highly efficient next-generation tandems due to excellent optoelectronic properties, low-cost manufacturability, and bandgap tunability. Here, we alloy chlorine into the perovskite lattice to create a triple halide wide bandgap perovskite absorber, a phase space that has thus far been overlooked. We show that chlorine is incorporated into the lattice in molar amounts up to 15%. The addition of chlorine doubles the charge carrier mobilities and lifetimes of the material. We show that a 1.67 eV triple halide perovskite does not experience photoinduced halide phase segregation under intensities up to 100 suns. Finally, we incorporate triple halide perovskite into solar cells, obtaining single junction devices with open-circuit voltages >1.2 V and >20% efficiency, and monolithic perovskite/silicon tandem solar cells with voltages approaching 1.9 V and >27% efficiency. Solar cells with the triple halide perovskite absorber retain 95% of their initial efficiency under maximum power point tracking at 60°C under white light illumination for 1000 hours.

Mike McGehee is a Professor in the Chemical and Biological Engineering Department at the University of Colorado Boulder.  He is the Associate Director of the Materials Science and Engineering Program and has a joint appointment at the National Renewable Energy Lab.  He was a professor in the Materials Science and Engineering Department at Stanford University for 18 years and a Senior Fellow of the Precourt Institute for Energy.  His current research interests are developing new materials for smart windows and solar cells. He has previously done research on polymer lasers, light-emitting diodes and transistors as well as transparent electrodes made from carbon nanotubes and silver nanowires. His group makes materials and devices, performs a wide variety of characterization techniques, models devices and assesses long-term stability.  He received his undergraduate degree in physics from Princeton University and his PhD degree in Materials Science from the University of California at Santa Barbara.

Donor/acceptor interfaces are ubiquitous building blocks of organic and hybrid materials for optoelectronic and photovoltaic applications. In-depth understanding of their electronic and optical characteristics is therefore essential to gain full control on their structure and properties. First-principles methods such as (time-dependent) density-functional theory [1] and many-body perturbation theory [2] offer an ideal trade-off between accuracy and numerical complexity to complement experiments in the study of these systems. In this talk, I will analyze electronic and optical response of doped organic semiconductors [3-5] in relation with experiments [6-8]. I will also discuss the earliest stage of formation of coherently driven optical transitions in a prototypical hybrid inorganic/organic interface, focusing on the critical role of electron-vibrational coupling and on its influence on the charge-transfer mechanisms [9]. 

References
[1] J. Krumland, A. M. Valencia, S. Pittalis, C. A. Rozzi, and C. Cocchi, J. Chem. Phys. 153, 054106 (2020).
[2] C. Cocchi and C. Draxl, Phys. Rev. B 92, 205126 (2015)
[3] A. M. Valencia and C. Cocchi, J. Phys. Chem. C 123, 9617 (2019)
[4] A. M. Valencia, M. Guerrini, and C. Cocchi, Phys. Chem. Chem. Phys. 22, 3527 (2020).
[5] R. Schier, A. M. Valencia, and C. Cocchi, J. Phys. Chem. C 124, 14363 (2020).
[6] A. E. Mansour, D. Lungwitz, T. Schultz, M. Arvind, A. M. Valencia, C. Cocchi, A. Opitz, D. Neher, and N. Koch, J. Chem. Mater. C 8, 2870 (2020).
[7] M. Arvind, C. E. Tait, M. Guerrini, J. Krumland, A. M. Valencia, C. Cocchi, A. E. Mansour, N. Koch, S. Barlow, S. R. Marder, J. Behrends, and D. Neher, J. Phys. Chem. B 124, 7694 (2020).
[8] C. P. Theurer, A. M. Valencia, J. Hausch, C. Zeiser, V. Sivanesan, C. Cocchi, P. Tegeder, and K. Broch, J. Phys. Chem. C 125, 6313 (2021).
[9] M. Jacobs, J. Krumland, A. M. Valencia, H. Wang, M. Rossi, and C. Cocchi, Adv. Phys. X 5, 1749883 (2020).

Caterina Cocchi received her PhD in physics from the University of Modena and Reggio Emilia, Italy, in 2012. She moved to Germany in 2013, first as post-doctoral scientist and then, from April 2017, as Junior Professor for “Theory of excitations in low dimensional systems” at the Physics Department of the Humboldt-Universität zu Berlin. Since April 2020 she is full professor of “Theoretical solid state physics” at the University of Oldenburg.

Harvesting energy from any particles with kinetic energies exceeding the energy of chemical bonds, i.e. energies above a few eV, raises the possibility that the particles introduce permanent damage in the materials used for the conversion. The mechanisms by which energetic particles have been examined systematically since the 1950's, and are very well understood in some cases, and
poorly in others. In this talk, I briefly review the basic physics understanding, stemming both from experiments and simulations, of radiation effects induced in hard condensed matter by ions and photons. I also consider as a specific case study what kind of damage is  expected to be produced by solar wind protons in semiconductor materials.

Conventional wisdom has it that the chemical changes caused by ionizing radiation are due to the formation of radicals and their subsequent (re-)combination. This is especially true in the field of Astrochemistry, where ionizing radiation is the primary driver for chemical conversion. There are, however, problems with this theory. I will, in this talk, briefly explain the ways that ionizing radiation can interact with matter, before giving an overview of the (sometimes surprisingly specific) kinds of chemical reactions that follow.

Jan Hendrik Bredehöft is a physical chemist with an interest in the prebiotic evolution of biomolecules and the eventual emergence of life. In 2017 he received his Habilitation from the University of Bremen, where he heads the Astrochemistry group, studying the interaction of (secondary) electrons with condensed matter.

Cosmic radiation is one of the limiting factors for long-duration space missions. For the assessment of radiation risk for humans DLR has been developing among others active radiation detectors for usage (i) onboard ISS, (ii) satellites, (iii) Moon orbit and surface, (iv) and for exploration missions. DLR works on models of the radiation field and cross-benchmarks the models and the radiation detectors. In the talk, we present development steps of a dosimeter and show dosimetry data from several space missions.

Karel is since 2002 research fellow at German Aerospace Centre, he leads the electronics development of active instruments for dosimetry of cosmic radiation in space. PhD in biomedical engineering in 2000. Current activities: Artemis I (Orion MPCV) payload development (MARE), Astrobotic Moon Lander Payload, MATROSHKA III ISS dosimetry suite.

In order to achieve the goals of the German energy transition changes in the energy consumption of private households are also required. In this context, efficiency, consistency and sufficiency strategies should be considered.

The talk presents the results of a study that dealt with the question of what effects the own production and/or use of renewable energies has on the energy consumption of private households. In addition to changes in everyday actions, the focus is also on rebound effects.

I´m a research assistant at the artec Sustainability Research Center of the University Bremen with a background in politics and sustainability. My focus is on sustainable (energy)consumption and rebound-effects.

Susan Schorr^1,2

¹Helmholtz-Zentrum Berlin für Materialien und Energie, Abteilung Struktur und Dynamik von Energiematerialien

²Freie Universität Berlin, Institut für geologische Wissenschaften

Ternary nitrides ZnMIVN2 (MIV= Ge,Sn) are being considered as promising candidates for photovoltaic absorber materials, containing uniquely elements of low toxicity and low resource criticality [1]. It has been postulated based on DFT calculations that these compounds possess a mechanism for bandgap tuning through cation disorder [2].
We are using diffraction techniques to investigate the crystal structure and structural disorder of Zn1+xGe1-x(N1-xOx)2 (x<0.35) which allows us to distinguish between intrinsic and compositional cation disorder. Finally the relationship between cation disorder and the bandgap energy is discussed.

[1] Narang, et al., Adv. Mater. 26 (2014) 1235–1241.

[2] Skachkov, et al., Phys. Rev. B. 94 (2016) 205201.

Susan Schorr has a diploma in crystallography and a PhD in physics. She is the head of the Department Structure and Dynamics of Energy Materials at the Helmholtz-Zentrum Berlin and teaches at the Freie Universität Berlin.

Donor/acceptor interfaces are ubiquitous building blocks of organic and hybrid materials for optoelectronic and photovoltaic applications. In-depth understanding of their electronic and optical characteristics is therefore essential to gain full control on their structure and properties. First-principles methods such as (time-dependent) density-functional theory [1] and many-body perturbation theory [2] offer an ideal trade-off between accuracy and numerical complexity to complement experiments in the study of these systems. In this talk, I will analyze electronic and optical response of doped organic semiconductors [3-5] in relation with experiments [6-8]. I will also discuss the earliest stage of formation of coherently driven optical transitions in a prototypical hybrid inorganic/organic interface, focusing on the critical role of electron-vibrational coupling and on its influence on the charge-transfer mechanisms [9]. 

References
[1] J. Krumland, A. M. Valencia, S. Pittalis, C. A. Rozzi, and C. Cocchi, J. Chem. Phys. 153, 054106 (2020).
[2] C. Cocchi and C. Draxl, Phys. Rev. B 92, 205126 (2015)
[3] A. M. Valencia and C. Cocchi, J. Phys. Chem. C 123, 9617 (2019)
[4] A. M. Valencia, M. Guerrini, and C. Cocchi, Phys. Chem. Chem. Phys. 22, 3527 (2020).
[5] R. Schier, A. M. Valencia, and C. Cocchi, J. Phys. Chem. C 124, 14363 (2020).
[6] A. E. Mansour, D. Lungwitz, T. Schultz, M. Arvind, A. M. Valencia, C. Cocchi, A. Opitz, D. Neher, and N. Koch, J. Chem. Mater. C 8, 2870 (2020).
[7] M. Arvind, C. E. Tait, M. Guerrini, J. Krumland, A. M. Valencia, C. Cocchi, A. E. Mansour, N. Koch, S. Barlow, S. R. Marder, J. Behrends, and D. Neher, J. Phys. Chem. B 124, 7694 (2020).
[8] C. P. Theurer, A. M. Valencia, J. Hausch, C. Zeiser, V. Sivanesan, C. Cocchi, P. Tegeder, and K. Broch, J. Phys. Chem. C 125, 6313 (2021).
[9] M. Jacobs, J. Krumland, A. M. Valencia, H. Wang, M. Rossi, and C. Cocchi, Adv. Phys. X 5, 1749883 (2020).

Caterina Cocchi received her PhD in physics from the University of Modena and Reggio Emilia, Italy, in 2012. She moved to Germany in 2013, first as post-doctoral scientist and then, from April 2017, as Junior Professor for “Theory of excitations in low dimensional systems” at the Physics Department of the Humboldt-Universität zu Berlin. Since April 2020 she is full professor of “Theoretical solid state physics” at the University of Oldenburg.

Harvesting energy from any particles with kinetic energies exceeding the energy of chemical bonds, i.e. energies above a few eV, raises the possibility that the particles introduce permanent damage in the materials used for the conversion. The mechanisms by which energetic particles have been examined systematically since the 1950's, and are very well understood in some cases, and
poorly in others. In this talk, I briefly review the basic physics understanding, stemming both from experiments and simulations, of radiation effects induced in hard condensed matter by ions and photons. I also consider as a specific case study what kind of damage is  expected to be produced by solar wind protons in semiconductor materials.

Conventional wisdom has it that the chemical changes caused by ionizing radiation are due to the formation of radicals and their subsequent (re-)combination. This is especially true in the field of Astrochemistry, where ionizing radiation is the primary driver for chemical conversion. There are, however, problems with this theory. I will, in this talk, briefly explain the ways that ionizing radiation can interact with matter, before giving an overview of the (sometimes surprisingly specific) kinds of chemical reactions that follow.

Jan Hendrik Bredehöft is a physical chemist with an interest in the prebiotic evolution of biomolecules and the eventual emergence of life. In 2017 he received his Habilitation from the University of Bremen, where he heads the Astrochemistry group, studying the interaction of (secondary) electrons with condensed matter.

Cosmic radiation is one of the limiting factors for long-duration space missions. For the assessment of radiation risk for humans DLR has been developing among others active radiation detectors for usage (i) onboard ISS, (ii) satellites, (iii) Moon orbit and surface, (iv) and for exploration missions. DLR works on models of the radiation field and cross-benchmarks the models and the radiation detectors. In the talk, we present development steps of a dosimeter and show dosimetry data from several space missions.

Karel is since 2002 research fellow at German Aerospace Centre, he leads the electronics development of active instruments for dosimetry of cosmic radiation in space. PhD in biomedical engineering in 2000. Current activities: Artemis I (Orion MPCV) payload development (MARE), Astrobotic Moon Lander Payload, MATROSHKA III ISS dosimetry suite.

In order to achieve the goals of the German energy transition changes in the energy consumption of private households are also required. In this context, efficiency, consistency and sufficiency strategies should be considered.

The talk presents the results of a study that dealt with the question of what effects the own production and/or use of renewable energies has on the energy consumption of private households. In addition to changes in everyday actions, the focus is also on rebound effects.

I´m a research assistant at the artec Sustainability Research Center of the University Bremen with a background in politics and sustainability. My focus is on sustainable (energy)consumption and rebound-effects.

Susan Schorr^1,2

¹Helmholtz-Zentrum Berlin für Materialien und Energie, Abteilung Struktur und Dynamik von Energiematerialien

²Freie Universität Berlin, Institut für geologische Wissenschaften

Ternary nitrides ZnMIVN2 (MIV= Ge,Sn) are being considered as promising candidates for photovoltaic absorber materials, containing uniquely elements of low toxicity and low resource criticality [1]. It has been postulated based on DFT calculations that these compounds possess a mechanism for bandgap tuning through cation disorder [2].
We are using diffraction techniques to investigate the crystal structure and structural disorder of Zn1+xGe1-x(N1-xOx)2 (x<0.35) which allows us to distinguish between intrinsic and compositional cation disorder. Finally the relationship between cation disorder and the bandgap energy is discussed.

[1] Narang, et al., Adv. Mater. 26 (2014) 1235–1241.

[2] Skachkov, et al., Phys. Rev. B. 94 (2016) 205201.

Susan Schorr has a diploma in crystallography and a PhD in physics. She is the head of the Department Structure and Dynamics of Energy Materials at the Helmholtz-Zentrum Berlin and teaches at the Freie Universität Berlin.