Recent Progress on Defect Passivation of All-Inorganic Halide Perovskite Solar Cells

All-inorganic halide perovskite materials have attracted increasing attentions in recent years due to their superior stability and adjustable band gap which make them very suitable for the top cells of multi-junction solar cells. Nonetheless, the power conversion efficiency of all-inorganic halide perovskite solar cells is still far from satisfaction. The widespread use of the conventional solution method in the preparation process causes many different defects and carrier transport barriers at the grain boundaries and interfaces of the perovskite films, which can cause severe hysteresis behavior and non-radiative recombination, resulting in low efficiency and hindering their rapid commercialization. While, the selection of suitable passivation materials and techniques can have the most significant potential in reducing the defect recombination centers between the bulk perovskite, the film surface and grain boundaries, and the interface between the various communities (perovskite/electron transport layer [ETL], perovskite/hole transport layer [HTL]). Herein, this study reviews the current research process on various passivation strategies developed for all-inorganic halide perovskite solar cells, especially for the defects in the perovskite surface, and grain boundaries, perovskite/HTL interface and perovskite/ETL interface. Finally, the authors look ahead to the prospects and challenges of exploring defect passivation in all-inorganic halide perovskite solar cells.