Regensburg 2022 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 49: Polymer and Molecular Dynamics, Friction and Rheology
CPP 49.4: Vortrag
Freitag, 9. September 2022, 12:15–12:30, H39
Dynamics in polymer-fullerene blends for photovoltaic applications studied with quasielastic neutron scattering — •Dominik M. Schwaiger1, Wiebke Lohstroh2, and Peter Müller-Buschbaum1,2 — 1TU München, Physik-Department, LS Funktionelle Materialien, 85748 Garching — 2MLZ, TU München, 85748 Garching
In organic photovoltaics, donor - acceptor bulk heterojunctions are of- ten used as active layer due to their superior performance compared to e.g. planar structured devices. In this optically active polymer layer, photons are absorbed, excitons are created, subsequently dissipated at a material interface and hence free charges are provided. A promising low-bandgap electron donor material is the conjugated polymer PTB7 that is often used in combination with the fullerene derivate PCBM. Besides a large number of studies on structure and electrical prop- erties, the level of knowledge about dynamics in this system is very limited. We investigated films of PTB7, PCBM and different blends of these two, prepared out of chlorobenzene solutions. Quasielastic neutron scattering experiments were performed to determine hydro- gen dynamics on a pico- to nanosecond timescale. In addition, two well established techniques for performance enhancement in organic photovoltaics, namely the addition of DIO to the casting solution and a methanol posttreatment of the active layer, are applied and their influence on the polymer dynamics is investigated.