Origin of the Hysteresis in I–V Curves for Planar Structure Perovskite Solar Cells Rationalized with a Surface Boundary-induced Capacitance Model

Abstract

Abstract For efficient hybrid solar cells based on organometal halide perovskites, the real origin of the I–V hysteresis became a big issue and has been discussed widely. In this study, simulated I–V curves of different equivalent circuit models were validated with experimental I–V curves of a planar perovskite solar cell with the power conversion efficiency (PCE) of 18.0% and 8.8% on reverse scan (from open circuit to short circuit) and forward scan (from short circuit to open circuit), respectively. We found that an equivalent circuit model with a series of double diodes, capacitors, shunt resistances, and single series resistance produces simulated I–V curves with large hysteresis matching with the experimentally observed curves. The electrical capacitances generated by defects due to the lattice mismatch at the TiO2/CH3NH3PbI3 and CH3NH3PbI3/spiro-OMeTAD interface are truly responsible for the hysteresis in perovskite solar cells.