Simple preparation of highly efficient MAxFA1−xPbI3 perovskite films from an aqueous halide-free lead precursor by all dip-coating approach and application in high-performance perovskite solar cells

All sequential-dip-coating deposition of mixed organic cationic MAxFA1−xPbI3 perovskite films from an aqueous non-halide lead precursor solution was effectively developed. Efficient crystal phase and surface morphologies of MAxFA1−xPbI3 perovskite films were successfully realized by varying MAI/FAI molar ratios in precursor solution over as-prepared Pb(NO3)2 layer. The various grain sizes and boundaries as well as cubical lumps of MAxFA1−xPbI3 perovskite crystal were also modulated after annealing at 120 °C of produced MAxFA1−xPbI3 perovskite films formed with suitable concentrations of MAI and FAI solution. Interestingly, all-dip-coating-treated MAxFA1−xPbI3 perovskite layers have no presence of δ-FAPbI3 perovskites, even at low MAI insertion into the FAI solution. Efficient device performances and improved stability with a power conversion efficiency of ~ 14.1% in perovskite solar cell devices with the all-dip-coating processed MA0.5FA0.5PbI3 perovskite layers realized by incorporating Pb(NO3)2 layers into MAI/FAI (1/1 molar ratio) solution.