Hannover 2016 – wissenschaftliches Programm
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MO: Fachverband Molekülphysik
MO 6: Posters 1: Novelties in Molecular Physics: Femtosecond Spectroscopy
MO 6.3: Poster
Montag, 29. Februar 2016, 16:30–19:00, Empore Lichthof
Theoretical analysis of exciton annihilation in Squaraine-Squaraine Copolymers — •Kilian Hader1, Christoph Lambert2, Volkhard May3, and Volker Engel1 — 1Universität Würzburg, Institut für Physikalische und Theoretische Chemie, Emil-Fischer-Str. 42, Campus Nord, 97074 Würzburg, Germany — 2Universität Würzburg, Institut für Organische Chemie, Am Hubland, 97074 Würzburg, Germany — 3Institut für Physik, Humboldt Universität, Newtonstr. 15, D-12489 Berlin, Germany
We use a microscopic model [1] to describe exciton annihilation processes in Squaraine-Squaraine Copolymers. Transient absorption traces measured at different laser powers exhibit an unusual time-dependence [2]. The analysis shows that, at shorter times, exciton-exciton annihilation, being effective through the laser excitation of next-neighbor building blocks, determines the excited state decay. At later times, excitations being localized on units which are not directly connected remain so that diffusion or smaller long range interactions are the rate-limiting step leading to a slower decay.
[1] V. May, J. Chem. Phys. 140, 054103 (2014) [2] S. F. Völker, A. Schmiedel, M. Holzapfel, K. Renziehausen, V. Engel, C. Lambert, J. Phys. Chem. C, 118, 17467 (2014)