Dresden 2017 – wissenschaftliches Programm
CPP 59.7: Vortrag
Donnerstag, 23. März 2017, 17:15–17:30, ZEU 222
Origin of high energy photoluminescence in poly(3-hexylthiophene) films — •Philipp Ehrenreich1, Daniel Proepper2, Stefan Jores1, Alexander Boris2, and Lukas Schmidt-Mende1 — 1Department of Physics, University of Konstanz, POB M 680, Konstanz 78457, Germany — 2Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, 70569 Stuttgart, Germany
A deeper understanding of exciton dynamics in polymer films is crucially important for improving charge generation in organic photovoltaics further. The large number of already existing polymers and unlimited possibilities of designing new materials demands for model systems, to which a comparison is possible. For this purpose, poly(3-hexylthiophene) is commonly used. Nonlinear decay kinetics have been interpreted by means of hot-excitons, torsional relaxation effects or exciton dissociation at amorphous/crystalline interfaces. However, it is often seen that observations vary. This is attributed to structural or energetic differences that depend on processing conditions. Using temperature dependent time-resolved photoluminescence measurements in combination with low temperature ellipsometry, we can show that P3HT is indeed a model system that follows the common diffusion model of excitons. Based on our results we can exclude the existence of hot-exciton emission as well as an impact of torsional relaxation dynamics on exciton decay dynamics.