Mainz 2017 – wissenschaftliches Programm

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SYAD: Symposium SAMOP Dissertation-Prize 2017

SYAD 1: SAMOP Dissertation-Prize

SYAD 1.1: Hauptvortrag

Mittwoch, 8. März 2017, 11:00–11:30, RW 1

Exciton transport in disordered organic systems — •Franziska Fennel — Inst. für Physik, Universität Rostock, Albert-Einstein-Str. 23, 18051 Rostock — Center for Nanosystems Chemistry, Universität Würzburg, Theodor-Boveri-Weg, 97074 Würzburg

Large migration distances of Frenkel excitons in organic polymers and molecular systems are of high relevance for applications such as light harvesting systems and organic solar cells. A common property of spatially disordered organic systems, like polymers, is a substantially reduced exciton migration distance due to their significant energetic disorder, i.e. a variation of the electronic excitation energy between the individual sites. In order to calculate the exciton migration distance under the presence of energetic disorder, we developed an extension of the conventional Förster approach. It allows for a reliable prediction based on easy accessible observables like the absorption and emission spectrum. By means of transient absorption measurements, we characterized the energetic disorder of a model system and predicted the exciton diffusion length. In a second step the exciton diffusion length was experimentally determined by exciton exciton annihilation. The agreement between experiment and model demonstrates the reliability of the extended Förster approach.

Finally, I will show that the energetic disorder can be strongly reduced by self-assembly of molecules to large supramolecular structures and enhanced exciton migration distances result. Understanding the exciton migration on these complex structures and the formulation of design principles will pave the way for enhanced exciton migration.