Layer-by-layer deposition of organic molecules controlled by selective click reactions – Publication by A8 (Koert/Dürr) in Chemistry of Materials  

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In a joint effort, the research groups led by Ulrich Koert and Michael Dürr realized the controlled layer-by-layer synthesis of organic molecular structures on silicon.

Two selective click reactions are employed for the controlled layer-by-layer synthesis or organic structures on silicon. Each reaction step is performed in solution and monitored by means of X-ray photoelectron spectroscopy under ultra-high vacuum conditions. Reprinted with permission from Chem. Mater. 2024. Copyright 2024 American Chemical Society.

The application of molecular layer deposition on silicon surfaces may open the route to directly synthesizing organic molecular architectures with tailored physical and/or physicochemical properties on the technologically most relevant silicon substrates (“more than Moore”). 

In their most recent publication, the researchers from A8 show how to use a combination of two selective and orthogonal click reactions (Cu-mediated and strain promoted azide-alkyne couplings) for such a controlled layer-by-layer growth of organic architectures on Si(001). Starting point was the Si(001) substrate, which was selectively functionalized with a substituted cyclooctyne under ultrahigh-vacuum (UHV) conditions. The subsequent layer-by-layer synthesis using the two orthogonal click chemistry reaction steps was then performed in solution in an alternating fashion. The product of each reaction step was analyzed in UHV by means of X-ray photoelectron spectroscopy; controlled layer-by-layer growth up to 11 molecular layers was realized and monitored in this way.

Together with previous studies of the researchers from A8 (Koert/Dürr), B5 (Höfer/Mette) and A6 (Tonner) on selective functionalization of the Si(001) surface and the combination of UHV-based surface chemistry with solution-based click chemistry, a complete toolbox for the well-controlled growth of molecular structures on silicon is now available.

Publication

T. Glaser, J.A. Peters, D. Scharf, U. Koert, M. Dürr
Layer-by-Layer Deposition of Organic Molecules Controlled by Selective Click Reactions
Chem. Mater. 36 (2024) 561 DOI:10.1021/acs.chemmater.3c02707

Contact

Prof. Dr. Ulrich Koert
Philipps-Universität Marburg
SFB 1083 project A8
Tel.: 06421 28-26970
EMAIL

Prof. Dr. Michael Dürr
Justus-Liebig-Universität Gießen
SFB 1083 project A8
Tel.: 0641 99-33490
EMAIL

Enhanced Circular Dichroism and Polarized Emission in an Achiral, Low Band Gap Bismuth Iodide Perovskite Derivative

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Johanna Heine (A15) and Sangam Chatterjee (B2) successfully prepared a novel iodido bismuthate that shows strong optical activity despite being achiral

Reprinted with permission from J. Am. Chem. Soc. 2023. Copyright 2023 American Chemical Society.

Lead halide perovskites and related main group halogenido metalates offer unique semiconductor properties and diverse applications in photovoltaics, solid-state lighting, and photocatalysis. Recent advances in incorporating chiral organic cations have led to the emergence of chiral metal-halide semiconductors with intriguing properties such as chiroptical activity and chirality-induced spin selectivity. This enables the generation and detection of circularly polarized light and spin-polarized electrons for applications in spintronics and quantum information, fields that use the spin of electrons or photons to store and process data.

However, understanding the structural origin of chiroptical activity remains challenging due to macroscopic factors and experimental limitations. In general, chiroptical activity originates in the crystal symmetry of the solid state. However, the compound does not need to be chiral to exhibit chiroptical activity. Some non-centrosymmetric crystal classes are sufficient as well – a fact that is often overlooked in current research.

The groups of Dr. Heine (A15) and Prof. Chatterjee (B2) present a novel achiral perovskite derivative [Cu2(pyz)3(MeCN)2][Bi3I11] (pyz = pyrazine; MeCN = acetonitrile), that exhibits remarkable circular dichroism. Notably, single crystals display linear and circular optical activity as well as a significant degree of circularly polarized photoluminescence. The magnitude of these effects on par or even larger than what can be achieved by incorporating chiral organic molecules into perovskites. These findings provide insights into the macroscopic origin of circular dichroism and offer design guidelines for developing materials with high chiroptical activity without expensive chiral building blocks.

Publication

J. Möbs, P. Klement, G. Stuhrmann, L. Gümbel, M. Müller, S. Chatterjee, J. Heine
Enhanced Circular Dichroism and Polarized Emission in an Achiral, Low Band Gap Bismuth Iodide Perovskite Derivative
J. Am. Chem. Soc. 145 (2023) 23478 DOI:10.1021/jacs.3c06141

Contact

Dr. Johanna Heine
Philipps-Universität Marburg
SFB 1083 project A15
Tel.: 06421 28-25482
EMAIL

34. Erfinderlabor: Scientific curiosity of the next Generation

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Hessen’s young MINT scientists conduct research on hydrogen and renewable energies within the SFB 1083 and Philipps University Marburg

Group foto of the closing event.

The 34th Inventors’ Lab (Erfinderlabor) of the Center for Chemistry (Zentrum für Chemie, ZFC) has successfully entered its finale. This year’s event was once again organized by the ZFC in cooperation with the Philipps University of Marburg and Elkamet and supported by other renowned cooperation partners such as the SFB 1083.

The practice-oriented workshop not only offers valuable career orientation on career opportunities in the MINT environment (mathematics, informatics, natural sciences and technology), but also always addresses a current topic of high socio-political and economic relevance. The focus of this years Inventors’ Lab was on renewable energies and hydrogen.

The sixteen students in four teams dealt with different issues in the context of the energy transition in different research groups, which are part of the SFB 1083. The topics were novel crystalline materials for the use of surface structures as energy converters, the functioning of batteries and the basics of laser spectroscopy as well as the self-construction of a spectrometer. Finally, the storage of hydrogen in metal hydrides was investigated.

The experts were impressed by the technical curiosity and quick comprehension, but also by the motivation and team spirit of the young people. “Here, a highly complex topic was explained precisely,” said Prof. Dr. Gregor Witte from the SFB during the virtual closing event.

The local project partner was the Chemikum Marburg represented by Dr. Christof Wegscheid-Gerlach. “The Inventors’ Lab exemplifies how scientific topics of the future can be communicated at the intersection of school and university, and thus how both levels of education can be interlinked.”

Contact

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