Recent advancement in perovskite solar cell with imidazole additive

In this review, we briefly summarize imidazole (Im) and its derivatives as an additive for perovskite solar cells (PSCs) to enhance not only efficiency but also long-term stability. The energy conversion efficiency of halide PSCs has exceeded 25%, which is one of the most attractive photovoltaic technologies. However, one of the main bottlenecks toward their commercialization is their long-term stability, which requires that their life span should be more than 20 years. Additive engineering has been demonstrated to be an effective way to improve the lifetime of devices. Some organic or inorganic additives have been used to promote grain growth and increase power conversion efficiency (PCE). To enhance the performance of PSCs, the intrinsic defect density of polycrystalline halide perovskite films is required to be low enough to suppress the charge recombination loss. The stability of Im-modified perovskite films was improved by limiting the migration of ions at grain boundaries. Im as an aromatic and diamine species with a small ionic radius can be alloyed appropriately to increase bond interaction with ABX3 lattice, thus resulting in additional stability to air, light, and heat. A-site cation engineering for perovskite by utilizing imidazolium (IA) cation affords a tolerance factor of 1 to modulate the perovskite crystallization. These findings will pave an avenue for synergistically modulating crystallization and healing defect in perovskite to achieve efficient and stable solar cells.