Perovskite solar cells passivated by guanidine-based materials

Based on the merits of over a decade of research, perovskite solar cells (PSCs) have emerged as a promising next-generation photovoltaic technology. However, the commercialization of PSCs is limited by the challenges involved in improving their efficiency and stability. The previous reports have demonstrated that passivation treatments repair the deep defects in perovskite crystals and at the perovskite/carrier transport layer interface, leading to an enhancement in PSC performance. Furthermore, guanidine-based materials have been intensively investigated in the passivation of PSC defects. In this review, the recent progress on the passivation of PSCs via guanidine-based materials is described in detail. First, the structure of PSCs and the application potential of guanidine-based materials in PSCs are introduced. Second, the passivation mechanisms of guanidine halide, non-halide guanidine, guanidine derivatives, and guanidine small molecules on PSCs are systematically analyzed. Finally, the conclusion and outlook for multifunctional guanidine-based materials are addressed.