Sequential-dip-coating processed mixed organic and inorganic perovskite film from halide-free lead precursor for efficient perovskite solar cells

A novel all-sequential-dip-coated (SDC) deposited FA₁MA_1−yPbI_3−xBr_x perovskite films have been synthesized from an aqueous non-halide lead precursor towards an environmentally benign, cost-effective, and efficient approach for high-performance perovskite solar cells (PrSCs). The mixed-cationic FA₁MA_1−yPbI_3−xBr_x perovskite layers ensure the fractional incorporation of Br into the perovskite crystal lattice. The insertion of Br contents was regulated by modulating the FABr concentration into the FABr/MAI mixed-cationic precursor solution. The incorporation of minor FABr into MAI helps to improve the surface coverage and crystallinity of the synthesized per-ovskite layer in contrast to the other perovskite films prepared with higher FABr content under the same environment. The PrSCs with these FA₁MA_1−yPbI_3−xBr_x perovskite layers displayed good de-vice performances and stability with a PCE of 11.1%. These outcomes reveal that the synthesis of FA₁MA_1−yPbI_3−xBr_x perovskite films with the SDC approach is more efficient because of the use of environmentally benign solvents for synthesizing lead and perovskite layers.