High-Efficiency CsPbBr3 Perovskite Solar Cells Obtained by Adding NH4Ac in Ambient Air Conditions

Stability is a crucial factor in the commercialization of perovskite solar cells (PSCs). CsPbBr3 PSCs, despite being less efficient than organic–inorganic hybrid PSCs, have a significant advantage in terms of stability. This makes them have promising potential for commercialization. In this study, high-quality all-inorganic CsPbBr3 perovskite films were prepared by using a multistep method in ambient air conditions. The crystalline quality of the CsPbBr3 films was improved by adding an appropriate amount of ammonium acetate (NH4Ac) to the PbBr2 precursor solution. Finally, carbon-based hole transport layer-free CsPbBr3 PSCs were fabricated by selecting NH4Ac-optimized light-absorbing layers and carbon electrodes that have a good commercialization prospect. Compared with control devices, the NH4Ac-optimized CsPbBr3 cell devices significantly improved in both efficiency and stability. The photoelectric conversion efficiency increased from 7.80% to 9.68%. This study provides an effective strategy for the preparation of high-quality films by using a multistep method and is also of great significance in promoting the commercialization of PSCs.