Eliminating J-V hysteresis in perovskite solar cells via defect controlling

Abstract

Organometal halide perovskite solar cell enjoys a rapid development in the last decade. However, the severe J-V hysteresis existed in perovskite solar cells leads to an over- or under-estimation of device efficiency. Herein, we introduce an ammonium salt as a new dopant of perovskite. As a result, the J-V hysteresis is almost eliminated, and a higher average efficiency is obtained. Besides, the degradation under constant illumination in ambient atmosphere observed in control devices is greatly improved. Thin film characterizations reveal that the addition of ammonium salt leads to smoother, more homogenous and better crystalline perovskite films, which exhibit more intense photoluminescence and a little longer fluorescent lifetime. Such improvements are owing to the dual-functional sulfoxide (SO) in the dopant that can assist in perovskite crystallization and passivate the surface defects, thus giving rise to the eliminated J-V hysteresis. Our results provide an easy way to eliminate the J-V hysteresis in perovskite solar cell.