Dresden 2011 – scientific programme

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MO: Fachverband Molekülphysik

MO 35: Spectroscopy in He Droplets

MO 35.8: Talk

Friday, March 18, 2011, 12:15–12:30, MER 02

Spectroscopy of PTCDA Monomers and Oligomers Attached to Helium Nanodroplets and Rare Gas Clusters — •Markus Müller, Matthieu Dvorak, Sebastian Müller, and Frank Stienkemeier — Physikalisches Institut, Universität Freiburg, Hermann-Herder-Str. 3, 79104 Freiburg

PTCDA (3,4,9,10 perylen-tetracarboxylic dianhydride) with its semiconducting properties is an auspicious material for organic device applications in photovoltaics and light-emitting diodes. To learn about the internal energy structure and possible deexcitation paths we employ helium nanodroplet isolation (HENDI)-spectroscopy as a well established technique to analyze the vibrational structure of molecules as well as excitonic transitions of complexes and nanostructures at low temperatures (380mK).

Laser induced fluorescence (LIF) excitation and emission spectra provide insight into the vibrational structure of the electronic ground state and the first electronically excited state. Emission intensities allow to determine the fraction of internal relaxation before emitting a photon. We will present LIF absorption and emission spectra of PTCDA monomers, dimers and oligomers attached to helium nanodroplets. Furthermore, measurements on neon and argon clusters have been performed in order to study the effect of the different cryogenic environments.