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O: Fachverband Oberflächenphysik

O 27: Metal substrates: Adsorption of organic / bio molecules IV

O 27.6: Vortrag

Dienstag, 15. März 2011, 12:30–12:45, PHY C213

4,4’-dithiodipyridine on Au(111): An STM and STS study — •Norbert Maurer, Anna Tschetschetkin, Berndt Koslowski, and Paul Ziemann — Institut für Festkörperphysik, Albert-Einstein-Allee 11, University of Ulm, D-89081 Ulm

Driven by the overwhelming possibilities of molecular electronics, systems of inorganic substrates covered with organic materials evolved to a widely investigated field. Promising candidates in this respect are thiols containing heterocyclic groups, e.g. the 4,4’-dithiodipyridine (PySSPy). We prepared PySSPy/Au(111) in vacuo at a reduced temperature and investigated the result by scanning tunneling microscopy and spectroscopy with emphasis on z-V spectroscopy. PySSPy forms islands on Au(111) exhibiting a 13x3√3 superstructure where the substrate-induced enantiomeric-excess of the molecules plays an important role. In that structure the LUMO is found to be at 3.2 eV with a slight variation depending on the position/coordination of the PySSPy. By annealing the structure at room temperature, a chain growth can be observed. The LUMO is then found at ∼2.1 eV. We conclude that the PySSPy dissociates at RT on Au(111) and forms a thiolate.