Dresden 2003 – scientific programme

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HL: Halbleiterphysik

HL 14: Poster I

HL 14.52: Poster

Monday, March 24, 2003, 17:00–19:30, HSZ/P2

Exciton diffusion in PTCDA studied by luminescence quenching experiments — •R. Schüppel, A. Holzhey, L. Staemmler, and M. Hoffmann — Institut für Angewandte Photophysik, TU Dresden, 01062 Dresden, Germany

For opto-electronic applications of organic semiconductors, the properties of the photo-excited states (excitons) have to be understood in detail. In particular the exciton diffusion length is a decisive parameter to optimize devices. We investigate the diffusion of excitons in PTCDA (perylene-3,4:9,10-tetracarboxylic-dianhydride) in luminescence quenching experiments on PTCDA/vanadyl-phthalocyanine double-layers. From a variation of the layer thickness of PTCDA, the diffusion process can be separated from the capture process at the interface. Assuming a three level model, one can distinguish between the primarily excited, short-lived states at 2.8 eV and the emitting, long-lived states around 1.7 eV. This distinction is experimentally realized by time-resolved luminescence measurements using a streak camera setup.