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O: Fachverband Oberflächenphysik

O 44: Focussed session: Functional molecules at surfaces II

O 44.9: Talk

Wednesday, March 28, 2012, 13:00–13:15, A 053

Role of the electronic structure of adsorbate/substrate complexes on the photoisomerization ability — •Michael Schulze, Christopher Bronner, Sebastian Hagen, and Petra Tegeder — Freie Universität Berlin, Fachbereich Physik, Arnimallee 14, 14195 Berlin

We use two-photon photoemission to study two molecular photoswitches at the Au(111) surface, namely azobenzene and its derivative tetra-tert-butyl- azobenzene (TBA). Electronic states at the substrate-adsorbate interface are found to be a sensitive probe for the isomerization state of TBA while azobenzene loses its switching ability at the surface. We partly attribute the latter to a shift of the highest occupied molecular orbital (HOMO) with respect to the gold d-bands which quenches the hole transfer involved in the switching mechanism of TBA.