Dynamics of exciton diffusion in poly(p-phenylene vinylene)/fullerene heterostructures

The exciton diffusion process in a poly(p-phenylene vinylene)- (PPV-)based derivative is investigated using time-resolved photoluminescence in conjugated polymer/fullerene heterostructures. The decay of the luminescence in the polymer/fullerene heterostructures is governed by exciton diffusion and subsequent dissociation at the polymer/fullerene interface. The decay curves of polymer layers with varying thickness are consistently modeled using an exciton diffusion constant of 3 × 10−4 cm2/s. The resulting exciton migration radius amounts to 6 nm, which is a measure for the active part of the PPV/fullerene heterojunction for photovoltaic applications.