München 2004 – wissenschaftliches Programm

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MO: Molekülphysik

MO 4: Femtosekundenspektroskopie: Elektrontransfer

MO 4.6: Vortrag

Montag, 22. März 2004, 12:15–12:30, HS 315

Pump-Probe-Spectroscopy of Ultrafast Heterogeneous Electron Transfer from Perylene to colloidal TiO₂ — •Ralph Ernstorfer¹, Lars Gundlach¹, Silke Felber¹, Petter Persson², Tobias Letzig¹, Carsten Zimmermann¹, Rainer Eichberger¹, and Frank Willig¹ — ¹Hahn-Meitner-Institut, Glienicker Str. 100, D-14109 Berlin — ²Department of Quantum Chemistry, Uppsala University, Sweden

The dynamics of photoinduced electron transfer from the excited singlet state of perylene chromophores into the conduction band of TiO₂ nanoparticles has been measured by fs-transient absorption spectroscopy in ultrahigh vacuum conditions. The energetic alignment of the molecular states relative to the semiconductor has been determined by stationary photoelectron spectroscopy. The electron transfer rate in such systems depends mainly on the electronic coupling between the adsorbate and the semiconductor. While retaining the anchor group of the chromophores, different bridge groups have been inserted between anchor group and dye. It will be shown that not only the distance between donor and acceptor but also the chemical nature of the bridge group determines the electron transfer rate.