Open-circuit voltage of organic photovoltaics: Implications of the generalized Einstein relation for disordered semiconductors

The open-circuit voltage dependence on light intensity and temperature is calculated for organic photovoltaics, taking into account the generalized Einstein relation for disordered semiconductors. The results show that open-circuit voltage losses in bulk-heterojunction organic solar cells are affected from the diffusion enhancement inherent to disordered semiconductors. The model is validated by the fitting to recently published experimental data.