Dresden 2009 – scientific programme

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O: Fachverband Oberflächenphysik

O 65: Time-resolved spectroscopies III

O 65.7: Talk

Friday, March 27, 2009, 12:45–13:00, SCH A315

Spectroscopy and dynamics of a surface-switchable phthalocyanine — •Nils Heinemann, Oleksiy Andreyev, Till Leißner, Timm Rohwer, and Michael Bauer — Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität Kiel

Molecular switching is a highly topical research field driven for instance by potential applications in molecular electronics.

The non-planar (shuttlecock-shaped) tin-phthalocyanine (SnPc) can adsorb in two different orientations on a surface due to its geometry. Wang et al. have demonstrated, that it is possible to induce a switching between these geometries with the tip of a scanning tunnelling microscope [1].

We present a two photon photoemission (2PPE) study of SnPc on Ag(111) suggesting the possibility of light-induced switching. The electronic structure of the adsorbate has been investigated and laser-induced, intensity dependent changes in the characteristic 2PPE spectra have been observed. We interpret this observation as a transient modification of the adsorbed molecules. Time-resolved 2PPE measurements show, that the characteristic relaxation dynamics take place on a femto- to picosecond time scale.

[1] Y. Wang, J. Kröger, R. Berndt, W. Hofer, Probing structural and electronic properties of ultrathin SnPc films on Ag(111) at the single molecule level, Angewandte Chemie (2008) (accepted)