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MO: Fachverband Molekülphysik

MO 9: Femtosecond Spectroscopy II

MO 9.1: Hauptvortrag

Dienstag, 13. März 2012, 10:30–11:00, V38.03

The Interplay between Electron Transfer and Förster Resonant Energy Transfer — •Igor Pugliesi¹, Patrick Kölle², Regina de Vivie Riedle², Heinz Langhals², and Eberhard Riedle¹ — ¹BioMolekulare Optik, LMU München — ²Dept. Chemie, LMU München

Energy and electron transfer are two fundamental processes on which the functioning of photoactive biological systems, solar cells and optoelectronic devices is based. The rates of these two processes can be described by Fermi's Golden Rule as they are both mediated by electronic coupling between donor and acceptor. This points to an intimate relation of energy and electron transfer on the electronic level. While energy transfer induced electron transfer has been observed in many artificial and biological systems, the inverse connection has not yet been investigated. Here we present an extended set of perylene diimide dyads with an donor-spacer-acceptor motif undergoing intramolecular FRET. Although the photoexcited donor is initially quenched by electron transfer from the spacer, after back transfer the energy of the donor is surprisingly transferred to the acceptor. Through broad-band pump-probe measurements and high level ab-initio calculations we show that the donor-spacer electron transfer state itself is responsible for the energy transfer via multipole-multipole interactions with the locally excited state of the acceptor. The dyads presented here are a first example that shows how electron transfer can be connected to energy transfer for the use in novel photovoltaic and optoelectronic devices.