Electrical characterization of the light induced degradation in CH3NH3PbI3 thin film

Recently, organic metal halide perovskites have emerged as one of the most promising photoactive materials in the field of photovoltaics. Different reports shows that CH3NH3PbI3 based perovskite solar cells (PSCs) have got a power conversion efficiency of up to 20{\%}. However, Perovskites suffer inherent instability and degrade rapidly when exposed to an ambient operating atmosphere which limits their further application to commercialization. Several studies have been carried out to resolve this problem to some extent. Proper encapsulation of the device prevents from degradation due to moisture and oxygen. However, degradation due to light irradiation is difficult to manage. Recent studies demonstrated that in the steady state operation of the device, the Voc is unchanged by continuous illumination of light. Rather the reduction in the power conversion efficiency follows the trend of the Jsc. In this work, the effect of light on the electrical conductivity of the CH3NH3PbI3 thin film which is deposited on a glass substrate is investigated using a four point probe conductivity measurement. Further, the temperature dependent conductivity measurement demonstrated that the dominant conduction type in the film is electronic rather than ionic type.