Defects and Their Passivation in Hybrid Halide Perovskites toward Solar Cell Applications

The rise of hybrid metal-halide perovskites as potential solar energy materials has revolutionized research on next-generation solar cells. According to recent studies, the rationale behind such success is the rich defect physics of materials. Studies on the origin of different types of prevailing defects, their formation, and mechanism of defect passivation have hence become decisive avenues. Herein, the possible origins of defects and different defect analysis techniques in hybrid halide perovskites are discussed. While initiating the discussion with the archetypal methylammonium lead halide, perovskites beyond the conventional ABX3 structure are included. In this direction, some major advancements to date on defect formation in the bulk of hybrid halide perovskites, at the grains and grain boundaries, are summarized. Numerous effective methods to passivate the defects and the adverse effect of defects on device efficiency are further highlighted. Hence, the prospect of defect engineering in perovskite materials is pointed toward improving the power conversion efficiency and long-term stability of perovskite solar cells (PSCs). The discussion rightfully addresses that the in-depth exploration of defect engineering is anticipated to have a gigantic impact toward the achievement of predicted efficiency in metal-halide PSCs.