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Molecular switches at inorganic surfaces

Giuseppe Mercurio, Sergey Subach, Stefan Tautz


The photoinduced switching manifests itself through modification of molecular conformation, i.e. reversible transformation between two (meta)-stable states characterised by different geometry, under illumination with different wavelength. This provides an experimental control over the structure and therefore properties of individual molecules and the overall molecular phase. It was found however, that isomerisation process occurs to differ in cases of free and adsorbed molecule [P. Tegeder, et al., Appl. Phys. A 88 (2007) 465.].
Our research in this project is aimed for understanding of observed effect. With Normal Incidence X-ray Standing Wave method, we study the interaction of azobenzene-derived molecular switches with metallic surfaces (Ag(111), Cu(111), Au(111)) in order to elucidate the difference in adsorption mechanism and thus to understand why on some surfaces switching is possible whereas on others it is forbidden. Experiments are carried out at the European Synchrotron Radiation Facility (Grenoble), beam line ID32. Obtained results are analyzed in conformity with DFT calculations of corresponding systems.


P. Tegeder, M. Wolf, Freie Univ. Berlin,
K. Reuter, Fritz-Haber-Inst., Berlin.