Dresden 2009 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
CPP: Fachverband Chemische Physik und Polymerphysik
CPP 40: POSTERS Electronic and Optical Properties
CPP 40.17: Poster
Donnerstag, 26. März 2009, 17:00–19:30, P3
The oligomer length dependence of triplet excition diffusion in polyfluorenes — •Sebastian T. Hoffmann1, Lekshmi Sudha Devi1, Irene Bauer1, Esther Scheler2, Peter Strohriegl2, and Anna Köhler1 — 1Department of Physics, University of Bayreuth, 95440 Bayreuth, Germany — 2Department of Chemistry, University of Bayreuth, 95440 Bayreuth, Germany
Triplet excitons play an important role in organic light emitting diodes and solar cells. However, very little is known about the mechanism by which the triplet excitons move and the microscopic parameters which govern triplet (Dexter) energy transfer in conjugated polymers. For a heavy metal containing conjugated polymer and its associated monomer, we have recently shown that triplet diffusion occurs by quantum mechanical tunneling at low temperatures and by thermally activated hopping above a transition temperature. [1,2]. In the present study, we extend our investigation to a PF2/6 polymer, trimer and dimer. We find that for the polyfluorene compounds, triplet diffusion can be described by the same model. As theoretically predicted2, the activation energy in the hopping regime and the transition temperature between the hopping and the tunnelling regime decreases with oligomer length. We discuss the influence of disorder on the transport process.
References [1] L. S. Devi, M. K. Al-Suti, C. Dosche, M. S. Khan, R. H. Friend, and A. Kohler, Physical Review B 78 (2008). [2] I. I. Fishchuk, A. Kadashchuk, L. S. Devi, P. Here-mans, H. Bassler, and A. Kohler, Physical Review B 78 (2008).