AbstractIn polymer:fullerene solar cells, the field-dependent photocurrent is due to a combination of polaron pair dissociation, competing with monomolecular recombination, and bimolecular recombination. We compare of the experimental photocurrent of P3HT:PCBM bulk heterojunction solar cells to Monte Carlo simulations of bilayer and bulk heterojunction devices. The shape of the photocurrent can be reproduced, the high quantum yield, however, cannot be explained with help of the simulations. In order to analyse the dominant experimental recombination mechanism, we apply the photo-CELIV technique. Our data can be fitted with bimolecular recombination, but only if a reduced Langevin recombination factor is assumed. Thermalisation is accounted for by measuring the time-dependent charge carrier mobility.
