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AKB: Biologische Physik
AKB 200: Poster Session II
AKB 200.17: Poster
Dienstag, 8. März 2005, 17:00–19:00, Poster TU C
Study of Energy-Transfer Processes in Metallo-Porphyrin Artificial Light-Harvesting Molecules — •Joachim Zeller1,2, Robert Hauschild1, Gernot Riedel1, Teodor S. Balaban2,3, Heinz Kalt1,2, N. Berova4, and K. Nakanishi4 — 1Institut fuer Angewandte Physik, Universitaet Karlsruhe (TH), 76131 Karlsruhe — 2Centrum fuer Funktionelle Nanostrukturen, Universitaet Karlsruhe (TH), 76131 Karlsruhe — 3Institut für Nanotechnologie, Forschungszentrum Karlsruhe, 76021 Karlsruhe — 4Columbia University, New York, USA
Artificial light harvesting molecules mimic photosynthesis in which light is transformed into chemical energy. They consist of an antenna, which absorbs light and acts as an energy donor, and an energy trap, to which the excitation is transferred. We investigated energy transfer in 3 conformationally different metallo-porphyrins using time-resolved fluorescence spectroscopy. They consist of a Zn-TPP moiety (antenna/energy donor) and a free-base-TPP moiety (energy trap) which are linked with a covalent steroidal bridge. An analysis of the time-resolved fluorescence spectra using the method of decay-associated spectra (DAS) reveals energy transfer between the Zn-TPP energy donor and the free-base-TPP energy trap with transfer times 0.91 ns, 0.99 ns and 1.1 ns for the 3 different molecule conformations. A comparison of the measured transfer times to the values expected from Foerster theory shows only limited agreement. These results will be compared to the energy transfer dynamics in H-bonded supramolecular porphyrin complexes.