Control of I−V Hysteresis in CH3NH3PbI3 Perovskite Solar Cell

ABSTRACT: Mismatch of current (I)-voltage (V) curves with respect to the scan direction, so-called I−V hysteresis, raises critical issue in MAPbI3 (MA = CH3NH3) perovskite solar cell. Although ferroelectric and ion migration have been proposed as a basis for the hysteresis, origin of hysteresis has not been apparently unraveled. We report here on the origin of I−V hysteresis of perovskite solar cell that was systematically evaluated by the interface-dependent electrode polarizations. Frequency ( f)-dependent capacitance (C) revealed that the normal planar structure with the TiO2/MAPbI3/spiro-MeOTAD config-uration showed most significant I−V hysteresis along with highest capacitance (10−2 F/cm2) among the studied cell configurations. Substantial reduction in capacitance to 10−3 F/cm2 was observed upon replacing TiO2 with PCBM, indicative of the TiO2 layer being mainly responsible for the hysteresis. The capacitance was intensively reduced to 10−5 F/cm2 and C−f feature shifted to higher frequency for the hysteresis-free planar structures with combination of PEDOT:PSS, NiO, and PCBM, which underlines the spiro-MeOTAD in part contributes to the hysteresis. This work is expecte