Dresden 2009 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 42: Poster Session II (Nanostructures at surfaces: arrays; Nanostructures at surfaces: Dots, particles, clusters; Nanostructures at surfaces: Other; Nanostructures at surfaces: Wires, tubes; Metal substrates: Adsorption of O and/or H; Metal substrates: Clean surfaces; Metal substrates: Adsorption of organic/bio moledules; Metal substrates: Solid-liquid interfaces; Metal substrates: Adsorption of inorganic molecules; Metal substrates: Epitaxy and growth; Heterogeneous catalysis; Surface chemical reactions; Ab-initio approaches to excitations in condensed matter; Organic, polymeric, biomolecular films– also with adsorbates; Particles and clusters)

O 42.47: Poster

Mittwoch, 25. März 2009, 17:45–20:30, P2

Photoemission studies of ex-situ prepared butanethiol and azobenzene derivative SAMs on Au(111): heat- and light-induced modifications of electron spectra — •Till Leißner, Nils Heinemann, Timm Rohwer, Oleksiy Andreyev, and Michael Bauer — Institut für Experimentelle und Angewandte Physik, Uni Kiel

Molecular switches and their intriguing properties attract much interest in the field of molecular electronics. Wet chemical deposition is a generally used method for coating of metallic surfaces with azobenzene-based switching molecules. In fact, the obtained SAMs are often imperfect and very inhomogeneous.

In this contribution we will present an improved technology of the ex-situ SAMs preparation. For our studies we choose butanethiol molecules as a model system for the molecular switch 3-(4-(4-Hexylphenylazo)phenoxy)propan-1-thiol adsorbed on a Au(111) surface. The quality of the obtained butanethiol and molecular switch SAMs was checked by means of two photon photoemission (2PPE) and LEED.

Furthermore, we will present data showing the impact of annealing and laser illumination (80 MHz fs-laser system) on butanethiol/Au(111) samples. In contrast to butanethiol, the molecular switch revealed strong irreversible modifications of the electronic structure under laser irradiation. This result will be discussed particularly in the context of a potential switching mechanism.