Bimolecular recombination coefficient calculation by in situ potentiometry in a bulk heterojunction organic photovoltaic material

摘要

Polymer fullerene bulk heterojunction (BHJ) systems are an important class of active materials; however, charge transport and recombination mechanisms in these materials are not yet completely understood. We use lateral bulk heterojunction devices to perform in situ potentiometry on the BHJ system P3HT:PCBM. From current vs. voltage measurements performed at different light intensities, we provide evidence that the recombination mechanism in this material is bimolecular. The potential profile of the device channel is also constructed from these measurements, which is then used to determine the mobility of both charge carriers and calculate the bimolecular recombination coefficient.