Düsseldorf 2007 – scientific programme

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MO: Fachverband Molekülphysik

MO 30: Poster: Spectroscopy in He droplets

MO 30.4: Poster

Tuesday, March 20, 2007, 16:30–18:30, Poster A

Spectroscopy of PTCDA Complexes in Helium Nanodroplets — •Matthieu Dvorak and Oliver Bünermann — Physikalisches Institut, Universität Freiburg, Hermann-Herder-Str. 3, 79104 Freiburg

PTCDA (3,4,9,10 perylen-tetracarboxylic dianhydride) is a planar organic semi-conducting molecule. It became a model system for organic semiconductors because of the well-ordered films formed on surfaces. Attaching this molecule to helium nanodroplets is one of the best methods to collect very precise spectroscopic information. Due to the very low temperature (0.4 K) and the superfluid properties, helium nanodroplets provide a very cold and weak interacting matrix, ideal for spectroscopic measurements. The ability to form complexes of a desired composition via successive doping opens the way to probe oligomers and size effects. The previous studies obtained in our group concerning PTCDA [1] are extended into the blue und UV spectral region. Spectra of the monomer transition as well as the excitonic transition for PTCDA stacks were collected. Comparison with theory and film spectra quantify the red shift for monomer and excitonic transition of PDTCA films.

[1] M. Wever and F. Stienkemeier, PRB 67, 125201 (2003)