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SYSM: Single Molecule Spectroscopy of Nanoobjects

SYSM 3: Single Molecule Spectroscopy of Nanoobjects III

SYSM 3.2: Hauptvortrag

Donnerstag, 5. März 2009, 17:10–17:50, VMP 8 HS

Single molecule studies of electronic excitation energy transfer: From transfer rates and mechanisms to manipulation — •Thomas Basche — Institut für Physikalische Chemie, Johannes Gutenberg-Universität Mainz

Electronic excitation energy transfer plays a key role for the functioning of natural light-harvesting complexes and light-emitting devices. In recent years single molecule spectroscopy of molecular aggregates has provided new insights into the fundamentals of this process. In order of increasing structural complexity we have studied simple molecular dimers and multichromophoric aggregates and (conjugated) polymers. It will be shown that the combination of frequency selective single molecule spectroscopy and confocal fluorescence microscopy at 1.4 K is a unique tool to study energy transfer in these systems. In particular, from the line widths of single molecule excitation spectra rate constants of energy transfer can be deduced directly. Detailed analyses shows that for several cases the mechanism of energy transfer cannot be described by the simple Förster model (dipole-dipole coupling). Furthermore, novel single molecule pump-probe experiments will be presented which allow for redirecting the excitation energy flow in individual molecular aggregates.