High-Efficiency\nCsPbBr<sub>3</sub> Perovskite Solar\nCells Obtained by Adding NH<sub>4</sub>Ac in Ambient Air Conditions

Stability\nis a crucial factor in the commercialization of perovskite\nsolar cells (PSCs). CsPbBr<sub>3</sub> PSCs, despite being less efficient\nthan organic–inorganic hybrid PSCs, have a significant advantage\nin terms of stability. This makes them have promising potential for\ncommercialization. In this study, high-quality all-inorganic CsPbBr<sub>3</sub> perovskite films were prepared by using a multistep method\nin ambient air conditions. The crystalline quality of the CsPbBr<sub>3</sub> films was improved by adding an appropriate amount of ammonium\nacetate (NH<sub>4</sub>Ac) to the PbBr<sub>2</sub> precursor solution.\nFinally, carbon-based hole transport layer-free CsPbBr<sub>3</sub> PSCs were fabricated by selecting NH<sub>4</sub>Ac-optimized light-absorbing\nlayers and carbon electrodes that have a good commercialization prospect.\nCompared with control devices, the NH<sub>4</sub>Ac-optimized CsPbBr<sub>3</sub> cell devices significantly improved in both efficiency and\nstability. The photoelectric conversion efficiency increased from\n7.80% to 9.68%. This study provides an effective strategy for the\npreparation of high-quality films by using a multistep method and\nis also of great significance in promoting the commercialization of\nPSCs.