Berlin 2018 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 111: Oxides and Insulators: Adsorption II
O 111.7: Vortrag
Freitag, 16. März 2018, 12:00–12:15, MA 041
Reversible and Efficient Photo-Switching of Azobenzene Derivatives on an Insulator Surface — •Simon Jaekel1, Antje Richter2, Robert Lindner2, Christophe Nacci1, Angelika Kühnle2, Stefan Hecht3, and Leonhard Grill1 — 1Department of Physical Chemistry, Karl-Franzens University of Graz, Austria — 2Institute for Physical Chemistry, Johannes-Gutenberg University Mainz, Germany — 3Department of Chemistry, Humboldt-University Berlin, Germany
Studying single molecular switches is of interest for a better understanding of fundamental physical and chemical processes, but also in view of their possible use in smart materials and molecular nanotechnology. Azobenzene is a prototypical molecular switch, which changes between trans and cis isomers at the central N=N bond upon an external stimulus. Adsorption on solid substrates allows to study their properties on the single-molecule scale. However, the mostly used metallic substrates can strongly influence the switching properties. Therefore, and also in view of potential electronic applications, the use of non-metallic substrates is desired. Here, we report non-contact atomic force microscopy (nc-AFM) results on the first switching of individual azobenzene molecules on an insulating calcite surface. Surprisingly, cis isomers appear on the surface already directly after preparation, indicating kinetic trapping. It is demonstrated that unlike on metals the molecules retain their efficient photoisomerization properties known from solution. Furthermore, the photoisomerization is shown to be reversible and selective, depending on the excitation wavelength.