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O: Fachverband Oberflächenphysik
O 81: Poster Focus Session: Molecular Nanostructures on Surfaces - New Concepts towards Complex Architectures
O 81.4: Poster
Mittwoch, 14. März 2018, 18:15–20:30, Poster A
Reversible switching of azobenzene tetramers molecules at a metal surface — •christophe nacci1, massimo baroncini2, alberto credi2, and leonhard grill1 — 1Department of Physical Chemistry, University of Graz, 8010 Graz, Austria — 2Photochemical Nanosciences Laboratory, University of Bologna, 40126 Bologna, Italy
Molecular switches revealing reversible isomerization properties are potentially relevant building blocks in the fields of molecular electronics, functionalized surfaces and information storage. Azobenzene is a prototypical molecular switch owing to the trans-cis isomerization of the central double nitrogen bond. Here, we report a study on azobenzene tetramers which are comprised of four azobenzene units in a tetrahedral arrangement. By using low-temperature scanning tunneling microscopy and spectroscopy (STM/STS) we can image individual molecules and study their switching properties with high spatial resolution. After adsorption on a Ag(111) surface we find molecular aggregates with characteristic hexagonal shapes that can be assigned to periodic adsorption sites. Reversible isomerization of azobenzene tetramer molecules was then induced either by the microscope tip or laser illumination. By analyzing the switching behavior, we obtain insight into the coupling with the surface and the effect on the physical/chemical properties of the molecules.