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LernortLabor awards Chemikum Marburg and Oe with LeLa-Prize 2023

On the LernortLabor conference, the Chemikum and the Oe project of SFB 1083 was awarded with the LeLa 2nd price for the outstanding experiments and educational offer in Marburg.

Award ceremony – Lernort Labor Meeting, Göttingen (v.l. Dr. Andreas Paetz (BMBF), Erich Weber (LK MR-BID), Luise Cleres, Dr. Marion Enßle, Dr. Ina Budde, Dr. Christof Wegscheid-Gerlach (alle Chemikum Marburg), Dr. Andreas Kratzer (LeLa) (Foto: Christoph Mischke, Goettingen).

Pupil labs are central facilities in many educations and STEM (Science, Technology, Engineering and Mathematics) regions. They are constantly offering new experiments, trying out new methods of teacher education and using creative methods. This year, the educational offer of the Chemikum Marburg and the SFB 1083 was awarded the LernortLabor (LeLa) 2nd Prize in the category “Experiment of the Year”. The jury judged the format to be an innovative and admirable approach. The LeLa Prize recognizes outstanding achievements by school laboratories and school laboratory networks.

The awarded experiment is a two-hour experimental workshop for young people from grade 9 and upwards and the general public, which focuses on the properties of hydrogen, its production, storage and ultimately the conversion, e.g. in fuel cells. SFB 1083-related experiments, like using solar cells for hydrogen production or the detection of hydrogen by means of suitable detectors, rounded off the overall very good impression of the Chemikum and the Oe project.

Poster presentation (Foto: Chemikum Marburg).

At the conference, the activities of the Oe project were also presented in detail with a poster contribution and within the lecture session “Science Communication, Public Relations and Research: School Labs in DFG-funded Projects”.

LernortLabor – Bundesverband der Schülerlabore e.V. represents extracurricular learning venues that focus on independent work, discovery, research and development in an authentic environment, such as a laboratory or workshop. LernortLabor is the leading lobby group for school laboratories in German-speaking countries and an expert contact for its members, stakeholders in the education scene as well as for politics, business and interested society.

Contact

Dr. Christof Wegscheid-Gerlach
Philipps-Universität Marburg
SFB 1083 project Oe
Tel.: 06421 28-25843
EMAIL

SFB Successfully Held Winter School 2023 in Hirschegg, Kleinwalsertal

After being postponed due to the pandemic situation, SFB 1083’s Winter School 2023 took place in presence from February 27th to March 3rd, 2023 at Marburger Haus in Hirschegg, Kleinwalsertal, Austria.

Groupfoto of the 40 participants. (Foto: Maximilian Dreher)

The 40 participants came from four collaborating institutions (33 from Philipps-Universität Marburg, four from Justus-Liebig-Universität Gießen, two from Universität Leipzig and one from Forschungszentrum Jülich). The event was organized by the SFB student speaker including 29 PhD Students, seven Master students and four postdoctoral researchers.

After a joint bus-ride from Marburg the program started with an official welcome and a first program overview by Maximilian Dreher, organizer and SFB student speaker. During the subsequent dinner, the participants started some first scientific discussions across departmental boundaries.

Poster session during the winter school. (Foto: Maximilian Dreher)

17 talks distributed over six sessions at three days were chaired by postdocs and experienced PhD students. The idea was to give introductory talks, such that everyone regardless of the own discipline and scientific experience could follow the topic to broaden the own horizon. Therefore, the talks were given an extra 10 min of discussion to answer as many open question as possible. All presenters did an excellent job of sharing their experience with the audience.

Highlights were talks by Carolin Kalff and Dominik Scharf, who presented a detailed lab day of an organic chemist or the talk by Willy Knorr, who gave insights into how to simulate transport characteristics of excitons.

Two poster session were held in the evenings after the dinner. Since only 12 poster per session were presented, everyone got the opportunity to have deep discussions at every poster. The overall atmosphere was very stimulating, such that the end of both sessions was late in the evening with many people still in discussion.

Besides the scientific program, the students got the opportunity to explore the beautiful landscape of Kleinwalsertal and enjoy the fresh air, while discussing the new insights they got during the week.

Chemical Doping by Fluorination and Its Impact on All Energy Levels of π-Conjugated Systems – Publication by A2 (Witte) and A8 (Koert/Dürr)

In their combined experimental and theoretical study published in the Journal of Physical Chemistry Letters, the groups of Holger Bettinger (Uni Tübingen), Ulrich Koert (A8) and Gregor Witte (A2) investigated the impact of fluorination on the C1s core level energies in fluorinated acene derivates.

Fluorination affects the inner potential and thus the energy levels, as symbolized by the water level. The electron binding energies are probed via X-ray photoelectron spectroscopy (XPS). (Image: Y. Radiev, Reprinted with permission from ACS J. Phys. Chem. Lett. 2023. Copyright 2023 American Chemical Society.).

Fluorination is commonly used to tailor the frontier energy levels. In the present study, the authors utilized the recent achievements in the synthesis of regio-selectively fluorinated acenes and systematically investigated the core level binding energies by means of X-ray photoelectron spectroscopy (XPS) complemented by density functional theory (DFT) calculations.

These investigations reveal that fluorination leads to core level shifts, which are not limited to directly fluorinated carbon atoms, but also affect more distant carbon atoms. These shifts depend on the degree of fluorination, indicating that local fluorination affects the electron density of the entire aromatic system similar to doping. Since commonly core level shifts are used as fingerprint signatures for the identification of molecular entities, the new results challenge this method for fluorinated π-conjugated molecules. Moreover, as these shifts do not only influence the core levels, but also the molecular valence orbital energies, transitions from the former into the latter are hardly affected by fluorination, as verified by X-ray absorption spectroscopy (NEXAFS) measurements.

Overall, the results show that not only the energies of frontier orbitals but also of all core levels in fully π-conjugated systems are affected by local fluorination, hence limiting a chemical identification based on supposedly characteristic core level energies since they instead depend also on the degree of fluorination.

Publication

D. Bischof, Y. Radiev, M.W. Tripp, P.E. Hofmann, T. Geiger, H.F. Bettinger, U. Koert, G. Witte
Chemical Doping by Fluorination and Its Impact on All Energy Levels of π-Conjugated Systems
J. Phys. Chem. Lett. (2023) DOI:10.1021/acs.jpclett.3c00287

Contact

Prof. Dr. Gregor Witte
Philipps-Universität Marburg
SFB 1083 project A2
Tel.: 06421 28-21384
EMAIL

Poster Presentation Prize at DPT 2022 in Karlsruhe

Marleen Axt (B6) was awarded for the best poster presentation at the 26th German Conference of Women in Physics („Deutsche Physikerinnentagung“, DPT) in Karlsruhe

Poster: „Time-resolved second-harmonic imaging microscopy: Ultrafast processes in ultrathin materials“ by M. Axt, J. E. Zimmermann, G. Mette, and U. Höfer (Philipps-Universität Marburg).

The German Conference of Women in Physics takes place annually since 1997. Supported by the German Physical Society (DPG), it offers female scientists of all areas of physics and at different carrier levels – from student to professor as well as physicists in industry – the possibility for networking and professional exchange. The 2022 conference had 250 participants and was hosted by the Karlsruhe Institute of Technology (KIT) from November 24-27, 2022.

In her contribution, Marleen Axt (project B6) reported on investigations of ultrafast charge-transfer processes between van-der-Waals monolayers of different twist angles by means of time-resolved second-harmonic imaging microsocopy, a technique developed by the Höfer group. The experiments provide insight into fundamental electronic properties at interfaces.

Dr. Philip Klement (B2 & B13) receives the dissertation prize of the Justus-Liebig-Universität Gießen

We congratulate Dr. Philip Klement on receiving the 2021/22 dissertation prize of the Justus-Liebig-Universität Gießen in the category natural sciences for his excellent dissertation.

Prof. Martin Kramer (r.) and Prof. Volker Wissemann (m.) congratulate Dr. Philip Klement (l.). Photo: JLU / Roland Duss

Philip Klement advanced the understanding of interfaces by his studies on the influence between materials and their environment. Interfaces ‒ junctions between materials ‒ are crucial for the design and performance of modern electronic devices. The impact of interfaces on the materials properties increases continuously as structures become smaller.

In his dissertation “Interface Phenomena in Two-Dimensional Materials” Philip Klement combined the dynamic and highly competitive research areas of two-dimensional materials and organic-inorganic perovskites to gain innovative insights. In his central work, he discovered free-standing, single layers of an organic-inorganic mixed crystal ‒ something not deemed feasible before. Further, he discovered the thickness dependence of the emission wavelength of this material ‒ an effect which was to date unknown. These results may enable the facile color tuning in next-generation efficient and sustainable lighting and display technologies.

Philip Klement continues to explore these new developments and opportunities as a member of the SFB projects B2 (Chatterjee) & B13 (Chatterjee/Volz), and in close collaboration with A15 (Heine).

Please see the coverage of the award ceremony for more impressions and a recent audio interview of Dr. Klement and Prof. Chatterjee for more details of their research (both in German).

Orbital Cinema and Cyclacenes: European Research Council awards two ERC Synergy Grants to SFB 1083 members

The European Research Council (ERC) awarded two Synergy Grant to the SFB-related projects “Photoemission Orbital Cinematography: An ultrafast wave function lab” (Orbital Cinema) and “Tackling the Cyclacene Challenge” (TACY).

The ERC has awarded two Synergy Grants to Michael Gottfried, Ulrich Höfer, Stefan Tautz, and collaborators, for projects that built on work in SFB 1083.

Foto: Jan Hosan

Michael Gottfried, Vice Speaker of SFB 1083, receives around 4.5 million euros for “Tackling the Cyclacene Challenge” (TACY). Cyclacenes are an elusive class of ring-shaped carbon-based molecules with unique electronic and magnetic properties. They are expected to provide fundamental insight into the chemistry of strained aromatic systems and to find applications in organic electronic and spintronics. The TACY team, which includes Michael Mastalerz from Heidelberg and Holger Bettinger from Tübingen, pursues the goal of generating cyclacenes for the first time. The ERC funds this project with around 11 million euros.

Foto: Jan Hosan

The second Synergy Grant was awarded to Ulrich Höfer and Stefan Tautz, project leaders of SFB 1083, and their collaborators Rupert Huber from Regensburg and Peter Puschnig from Graz. Ulrich Koert and Jens Güdde, two other SFB 1083 project leaders, are associated partners. Their project “Photoemission Orbital Cinematography: An ultrafast wave function lab”, in short “Orbital Cinema”, aims to reach sub-cycle time resolution in orbital videography and to actively shape and functionalize molecular orbitals with lightwaves. This project is funded with up to 11.4 million euros.

For further information about these projects, see the following:

Leopoldina awards Greve Prize to Kerstin Volz and Jürgen Janek

Physicist Kerstin Volz and physical chemist Jürgen Janek will receive the 2022 Greve Prize from the German National Academy of Sciences Leopoldina for their fundamental insights into rechargeable batteries.

Image: Rolf K. Wegst (l.) | Christian Stein/Philipps-Universität Marburg (r.).

Kerstin Volz, Speaker of the SFB 1083 and project leader of A5, A14 und B13, and Leopoldina member Jürgen Janek, Director of the Center for Materials Research at the Justus Liebig University Giessen, investigate electrochemical energy storage devices and novel materials therefore. Their research has helped to improve high-performance batteries and develop new, resource-saving electrochemical energy storage concepts.

In their collaborative work, Kerstin Volz and Jürgen Janek investigate processes in solid-state batteries and structural changes during operation. Using a combination of electron microscopic and electrochemical methods they have managed, for example, to shed light on aging phenomena which lead to reductions in battery capacity.

The German National Academy of Science Leopoldina’s Greve Prize is awarded to scientists or research teams in Germany. The newly established prize is awarded every two years on a specific topic and honors outstanding research achievements in the natural sciences/medicine and engineering sciences. This year, the topic was the scientific foundations of sustainable energy supply. The prize is endowed with 250,000 euros, with funds from the Greve Foundation.

For further information, please see the press release by the Leopoldina (in German and English) as well as by the Philipps University Marburg (in German).

Contact

Prof. Dr. Kerstin Volz
Philipps-Universität Marburg
SFB 1083 spokeswoman
Tel.: 06421 28-22297
EMAIL

F-Center Mediated Growth of Patterned Organic Semiconductor Films on Alkali Halides – Publication by A2 (Witte)

In a combined experimental and theoretical study, the groups of Gregor Witte (A2) and Jérôme Cornil from the University Mons present a new approach of patterning organic semiconductor films with simultaneous molecular orientation control based on an electrostatic stabilization at the film/substrate interface in the presence of F-centers in alkali halide substrates created by controlled electron irradiation.

Scheme of the process chain that allows transfer of patterned organic films to any non-water-soluble substrate. Reprinted with permission from ACS Appl. Mater. Interfaces 2022. Copyright 2022 American Chemical Society.

A key problem in organic electronics remains the lateral patterning and structuring of organic films for device applications since photo­lithography is not applicable due to the lack of chemical robustness of the organic materials in the etching process. Therefore, alternative approaches are necessary for the patterning of organic films.

In this study, Darius Günder et al. demonstrate that electron irradiation of KCl(100) substrates induces surface localized F-centers (halide vacancies) that strongly influence the molecular orientation and lateral structure of subsequently grown organic films. By combining AFM, SEM and XRD measurements they show for the case of dinaphto­thieno­thiophene (DNTT) that molecules adopt a recumbent molecular orientation and form elongated fibers while hexagonally shaped islands with upright orientation are present on pristine KCl. Interestingly, both morphologies exhibit epitaxial alignments that are understood by higher-order commensurabilities. A complementary DFT-based theoretical analysis in the group of Jérôme Cornil identified electrostatic interactions between F-centers and interfacial DNTT molecules as origin of the different film morphologies. Furthermore, shadow masks or electron beam lithography techniques also allow spatially selective surface irradiation to generate patterns of F-centers, and thus enable lateral structuring of DNTT films.

Finally, it could be shown that due to the water solubility of the alkali halide growth templates, the patterned organic films can also be transferred to other substrates, including amorphous elastomeric plastic substrates, while the lateral and orientational order remain fully intact, hence underlining the great potential of this new patterning method for device applications.

Publication

D. Günder, V. Diez-Cabanes, A. Huttner, T. Breuer, V. Lemaur, J. Cornil, G. Witte
F-Center-Mediated Growth of Patterned Organic Semiconductor Films on Alkali Halides
ACS Appl. Mater. Interfaces (2022) DOI:10.1021/acsami.2c13934

Contact

Prof. Dr. Gregor Witte
Philipps-Universität Marburg
SFB 1083 project A2
Tel.: 06421 28-21384
EMAIL

Obituary for Prof. Dr. Stephan W. Koch – Nachruf für Prof. Dr. Stephan W. Koch

Die Mitglieder des Sonderforschungsbereichs 1083 „Struktur und Dynamik innerer Grenzflächen“ trauern um Prof. Dr. Stephan W. Koch, der im September 2022 im Alter von 69 Jahren verstorben ist.

Foto: Tim van de Bovenkamp; Copyright: SFB 1083

Stephan W. Koch promovierte 1979 in Frankfurt und war von 1977 bis 1984 wissenschaftlicher Mitarbeiter am Institut für Theoretische Physik der Universität Frankfurt, an dem er auch bereits 1983 habilitierte. Nach drei Jahren als Stipendiat der F. Thyssen-Stiftung und der DFG im Rahmen eines Heisenberg-Stipendiums ging er 1986 als Associate Professor an das Physics Department and Optical Sciences Center der University of Arizona in Tucson, wo er 1989 zum Full Professor ernannt wurde. 1993 kam er dann nach Marburg und übernahm in Nachfolge von Otfried Madelung und Stefan Schmitt-Rink den Lehrstuhl für Theoretische Festkörperphysik an der Philipps-Universität Marburg, wobei er weiterhin Adjunct Professor an der University of Arizona blieb. Diesen beiden Stationen blieb er bis zu seiner Pensionierung treu.

Seine Forschungsschwerpunkte lagen auf dem Gebiet der theoretischen Festkörperphysik. Besonders interessierten ihn hier die theoretischen Grundlagen der Wechselwirkung von Licht mit Materie in Halbleitermaterialien sowie in Laserstrukturen und Mikro-Resonatoren.

Stephan W. Koch war ein herausragender, international hoch angesehener Wissenschaftler. Durch seine Arbeiten zur Vielteilchenphysik und den optoelektronischen Eigenschaften von Halbleitern trug er maßgeblich zum heutigen Verständnis von Festkörpern und insbesondere Halbleiternanostrukturen bei. Für seine Leistungen wurde er 1997 mit dem Leibniz-Preis der Deutschen Forschungsgemeinschaft (DFG) sowie 1999 mit dem Max-Planck-Forschungspreis der Alexander-von-Humboldt-Stiftung und der Max-Planck-Gesellschaft ausgezeichnet.

Stephan Koch hat die Forschungslandschaft der Marburger Physik entscheidend mitgeprägt. Von 1995 bis 2001 leitete er den erfolgreichen SFB 383 „Disorder on mesoscopic scales“ und war seit 2013 Mitglied des SFB 1083 „Structure and dynamics of internal interfaces“.

Stephan Koch verstand es, seine vielen Schülerinnen und Schüler für die Halbleiterphysik zu begeistern. Viele von Ihnen sind heute an Hochschulen und Forschungseinrichtungen tätig.

Mit großer Dankbarkeit und Anerkennung werden wir uns an ihn als einen stets aufgeschlossenen Kollegen erinnern, der in seinem gesamten Schaffen immer wieder neue Impulse gegeben und Zeichen gesetzt hat.

Unser tiefes Mitgefühl und unsere Anteilnahme gelten seiner Ehefrau und seinen Angehörigen.

Wir werden ihn vermissen.

 

Formation of Moiré Interlayer Excitons in Space and Time – Publication by B9 (Malic) in Nature

A large research team including Ermin Malic and coworkers observed the formation of a “dark” moiré interlayer exciton for the first time

A large number of so-called optically dark excitons form between two twisted layers of tungsten diselenide (top) and molybdenum disulfide (bottom) after optical excitation. (Reprinted with permission from Nature, link see below)

Atomically thin structures made of two-dimensional semiconductor materials are promising candidates for future devices in electronics, optoelectronics and photovoltaics. The properties of these semiconductors can be controlled by stacking atomically thin layers on top of each other. However, the angle of rotation in the structure of the semiconductors can be adjusted as desired, and this angle of rotation is of interest for the production of novel solar cells. Typical experimental approaches have only indirect access to the moiré interlayer excitons and are blind to the ‘dark’ excitons.

An international research team including Ermin Malic and coworkers from the SFB succeeded in directly visualizing so-called dark moiré interlayer excitons by using time-resolved ARPES measurements combined with microscopic many-particle theory. The researchers show how the time-resolved momentum microscopy provides deepest microscopic insights into these technologically relevant questions.

These results not only provide a fundamental insight into the formation of dark moiré interlayer excitons, but also open up a new perspective to study the optoelectronic properties of these new and fascinating materials, e.g., the signature of the moiré potential and the influence of the combined properties of the two twisted semiconductor layers.

For further information, please see the press release by the university of Göttingen (in German).

Publication

D. Schmitt, J.P. Bange, W. Bennecke, A.A. Al Mutairi, G. Meneghini, K. Watanabe, T. Taniguchi, D. Steil, D.R. Luke, R.T. Weitz, S. Steil, G.S.M. Jansen, S. Brem, E. Malic, S. Hofmann, M. Reutzel, S. Mathias
Formation of moiré interlayer excitons in space and time
Nature 608 (2022) 499 DOI:10.1038/s41586-022-04977-7

Contact

Prof. Dr. Ermin Malic
Philipps-Universität Marburg
SFB 1083 project B9
Tel.: 06421 28-22640
EMAIL

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