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

Abstract A novel all‐sequential‐dip‐coated (SDC) deposited FA 1 MA 1−y PbI 3−x Br 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 FA 1 MA 1−y PbI 3−x Br 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 FA 1 MA 1−y PbI 3−x Br x perovskite layers displayed good de‐vice performances and stability with a PCE of 11.1%. These outcomes reveal that the synthesis of FA 1 MA 1−y PbI 3−x Br x perovskite films with the SDC approach is more efficient because of the use of environmentally benign solvents for synthesizing lead and perovskite layers.