AG Prof. Dr. Schirmeisen
- AG Prof. Dr. Schirmeisen - Neu
Research Group Prof. Dr. André Schirmeisen
Institute of Applied Physics
Justus-Liebig University Gießen
35392 Gießen, Germany
10/2019 "Elusive cousins of graphene": In a cooperation with the Universities of Marburg, Oldenburg and Erlangen-Nürnberg a new 2D graphene allotrope was created by on-surface synthesis techniques. This material contains odd-numbered rings, and is predicted to possess unusual (opto)electronic properties. See also feature article
5/2019 "3D Imaging of Molecular Bonds": Our group has expanded the chemical bond imaging method to assess the 3D structure of organic molecules. In D. Martin-Jimenez et al., Physical Review Letters 122 (2019) 196101 see also news coverage: , Nature Research Highlights, Physics World
2/2019: Selectivity is a key parameter for building customized organic nanostructures via bottom-up approaches. Therefore, strategies are needed, which allow connecting molecular entities at a specific stage of the assembly process in a chemoselective manner. Studying the mechanisms of such reactions is the key to apply these transformations for the build-up of organic nanostructures. In a collaboration with Prof. Wegner (JLU), Prof. Mollenhauer (JLU) and Prof. Chi (Soochow University, China) we show the selective dehalogenation of 4-bromo-3-iodo-p-terphenyl on the Cu(111) surface using bond imaging atomic force microscopy.
D. Ebeling et al. "Adsorption Structure of Mono- and Diradicals on a Cu(111) Surface: Chemoselective Dehalogenation of 4-Bromo-3''-iodo-p-terphenyl", ACS Nano 13 (2019) 324
12/2018: New 3-year DFG project granted, which aims to unravel the "Molecular mechanisms of C-C coupling: A microscopic view into the on-surface chemical bonding processes". This is an interdisciplinary joint project together with Prof. Herman Wegner (organic chemistry, JLU) and Prof. Doreen Mollenhauer (physical chemistry, JLU).
8/2018: Site-selective functionalization of only one of two identical chemical groups within one molecule is highly challenging, which hinders the production of complex organic macromolecules. In cooperation with Prof. Lifeng Chi's group at Soochow University, China, we demonstrate that adsorption of 4,4″-diamino-p-terphenyl on a metal surface leads to a dissymmetric binding affinity. With low temperature atomic force microscopy, using CO-tip functionalization, we reveal the asymmetric adsorption geometries of 4,4″-diamino-p-terphenyl on Cu(111), while on Au(111) the symmetry is retained. For details see article: Q. Zhong, D. Ebeling, J. Tschakert, Y. Gao, D. Bao, S. Du, C. Li, L. Chi, A. Schirmeisen, "Symmetry breakdown of 4,4″-diamino-p-terphenyl on a Cu(111) surface by lattice mismatch" Nature Communications 9 (2018) 3277
6/2018: Ever since Louis Pasteur’s ground-breaking research we know today that molecular chirality plays an important role in our everyday life because enantiomers (i.e., mirror images) of the same molecules can interact with living organisms in completely different ways. Many chirality related phenomena, in particular, the underlying molecular recognition mechanisms, are still not well understood. This is because it is difficult to study chirality at the level of individual molecules. In our study together with Prof. Schreiner’s group at JLU we are using low temperature atomic force microscopy (AFM) to image individual tetramantane molecules on a copper surface. Our approach represents a new toolset for studying molecular recognition that can enlighten ourunderstanding about the role of chirality in nature. Ebeling, Sekutor, Stiefermann, Tschakert, Dahl, Carlson, Schirmeisen, Schreiner,
"Assigning the absolute configuration of single aliphatic molecules by visual inspection"
Nature Communications 9 (2018) 2420 (link to article)
3/2018: In cooperation with Prof. Lifeng Chi's group (Soochow University, China) we investigated hierarchical dehydrogenation reactions on a copper surface at the example of DATP molecules just published in JACS. Hierarchical control of chemical reactions is being considered as one of the most ambitious and challenging topics in modern organic chemistry. In this study, we have realized the one-by-one scission of the X–H bonds (X = N and C) of aromatic amines in a controlled fashion on the Cu(111) surface. Each dehydrogenation reaction leads to certain metal–organic supramolecular structures, which were monitored in single-bond resolution via scanning tunneling microscopy and noncontact atomic force microscopy. This paves the way for connecting molecules into complex structures in a more reliable and predictable manner, utilizing carefully tuned stepwise on-surface synthesis protocols. Link to article. Q. Li, B. Yang, J. Björk, Q. Zhong, H. Ju, J. Zhang, N. Cao, Z. Shi, H. Zhang, D. Ebeling, A. Schirmeisen, J. Zhu, L. Chi, "Hierarchical Dehydrogenation Reactions on a Copper Surface"
Journal of the American Chemical Society (JACS) 140 (2018) 6076
9/2017: Cooperation with Prof. Schreiner group (JLU) and Stanford university shows importance of Londons Dispersion forces for the self-assembly of Nanodiamonds in a new publication in ACS Nano. London dispersion (LD) acts between all atoms and molecules in nature, but the role of LD interactions in the self-assembly of molecular layers is still poorly understood. In this study, direct visualization of single molecules using atomic force microscopy with CO-functionalized tips revealed the exact adsorption structures of bulky and highly polarizable tetramantane molecules on Au(111) and Cu(111) surfaces. Link to article.
D. Ebeling, M. Sekutor, M. Stiefermann, J. Tschakert, J.E.P. Dahl, R.M.K. Carlson, A. Schirmeisen, P.R. Schreiner, "London Dispersion directs On-Surface Self-Assembly of  Tetramantane Molecules",
ACS Nano 11 (2017) 9459 (link to article)
9/2017: Cooperation of AG Schirmeisen and AG Thummes developed world's smallest pulse tube cooler "SUSY" reaching >50mW cooling power at 4K (with 1kW input power). Plug and play system using conventional 220V power plugs, no water cooling necessary. See upcoming article in Cryogenics (2017) (link to article)
7/2017: What are the limits of superlubricity? Our recent publications in cooperation with Prof. Stich (Slovak academy of sciences) pinpoints the limits of zero friction sliding due to size thresholds. Structural superlubricity describes the state of virtually frictionless sliding if two atomically flat interfaces are incommensurate, that is, they share no common periodicity. Despite the exciting prospects of this low friction phenomenon, there are physical limitations to the existence of this state. Theory predicts that the contact size is one fundamental limit, where the critical size threshold mainly depends on the interplay between lateral contact compliance and interface interaction energies. Here we provide experimental evidence for this size threshold by measuring the sliding friction force of differently sized antimony particles on MoS2. Link to article.
D. Dietzel, J. Brndiar, I. Stich, A. Schirmeisen, "Limitations of structural superlubricity: Chemical bonds versus contact size", ACS Nano 11 (2017) 7642
3/2017: Chemistry textbook reaction Ullman-coupling observed step-by-step at chemical bond level. Cooperation with Prof. Wegner (JLU) and Prof. Mollenhauer (JLU) sheds light on 'intermediate-state' during coupling reaction of Bromo-Triphenylene on Cu surfaces. Link to article.
S. Zint, D. Ebeling, T. Schlöder, S. Ahles, D. Mollenhauer, H. Wegner, A. Schirmeisen, "Imaging Successive Intermediate States of the On-Surface Ullmann Reaction on Cu(111): Role of the Metal Coordination",
ACS Nano 11 (2017) 4183
7/2016: Contact ageing of nanoparticles - New publication in PRL highlights the mechanism of ageing for individual nanoparticles by analysis of their stick-slip behaviour during sliding in this cooperation with Prof. Grütters group (McGill University, Canada). The term “contact aging” refers to the temporal evolution of the interface between a slider and a substrate usually resulting in increasing friction with time. Current phenomenological models for multiasperity contacts anticipate that such aging is not only the driving force behind the transition from static to sliding friction, but at the same time influences the general dynamics of the sliding friction process. To correlate static and sliding friction on the nanoscale, we show experimental evidence of stick-slip friction for nanoparticles sliding on graphite over a wide dynamic range.
M. Feldmann, D. Dietzel, A. Tikiel, J. Topple, P. Grütter, and A. Schirmeisen, "Universal Ageing Mechanism for Static and Sliding Friction of Metallic Nanoparticles", Physical Review Letters 117 (2016) 025502
11/2015: Announcement: The 611th Heraeus seminar with the topic "Mechanisms of Tribology" organized by Prof. André Schirmeisen, together with Prof. Bennewitz (Saarbrücken) and Dr. Dienwiebel (Karlsruhe) will take place from 29.3. - 1.4.2016 in Ban Honnef, Germany. We encourage especially young scientists and PhD-students to participate and submit a poster. The seminar will be completely funded and locally organized by the 'Wilhelm and Else Heraeus Foundation'. For accepted participants free board and lodging will be supplied by the 'WE Heraeus-Foundation'. More information on www.tribomechanisms2016.de
9/2015: The "6th European Nanomanipulation Workshop" was successfully held from 23.-25 September 2015 at the JLU Giessen. More information www.nanomanipulation.eu