Suppression of hysteresis in all-inorganic perovskite solar cells by the incorporation of PCBM

Abstract

All-inorganic halide perovskites (AIHPs) have become one of the most promising materials for commercial perovskite photovoltaics owing to their enhanced efficiency and thermodynamic stability. Output instability, such as current hysteresis, is stressed in organic-inorganic hybrid perovskite photovoltaics but is neglected in AIHP solar cells. Here, the origin and suppression of current hysteresis in AIHP solar cells are addressed from a microscopic viewpoint. The incorporation of fullerene into AIHP films efficiently suppresses ion migration, which alleviates the macroscopic current hysteresis in solar cells. This result is confirmed by both Kelvin probe force microscopy and conductive atomic force microscopy measurements. Our results provide an advanced understanding of the microscopic properties of AIHPs but also clearly clarify how to suppress the macroscopic current hysteresis, which further inspires the optimization of solar cells up to the levels of organic–inorganic hybrid counterparts.