Influence of excitons interaction with charge carriers on photovoltaic parameters in organic solar cells

We report on theoretical analysis of excitons annihilation on charge carriers in organic solar cells. Numerical calculations based on transient one–dimensional drift–diffusion model have been carried out. An impact of three quantities (an annihilation rate constant, an exciton mobility and a recombination reduction factor) on current density and concentrations of charge carriers and excitons is investigated. Finally, we discuss the influence of excitons interaction with electrons and holes on four photovoltaic parameters (a short–circuit current, an open–circuit voltage, a fill factor and a power conversion efficiency). The conclusion is that the annihilation process visibly decreases the efficiency of organic photocells, if the annihilation rate constant is greater than 1E−15 m3 s−1 .