The role of mobility in bulk heterojunction solar cells

In this letter, we employ a three-dimensional master equation calculation to investigate the mobility dependence of bulk heterojunction (BHJ) solar cell performance. By taking energetic disorder and morphology into consideration, we show mobility-enhanced device efficiency with a remarkable charge transport loss induced by molecular disorder and an open circuit voltage loss in high mobility region due to morphological defect-assisted bimolecular recombination. The result suggests that the description of interfacial processes is crucial in the modeling of BHJ photovoltaic devices. (C) 2011 American Institute of Physics. [doi:10.1063/1.3639273]