Sequentially dip-coated processed MAyFA1−yPbI3−xBrx perovskite layers from an aqueous halide-free lead precursor for efficient perovskite solar cells

A facile all-sequential-dip-coating deposition of MAyFA1−yPbI3−xBrx perovskite layers from an aqueous halide-free lead precursor, Pb(NO3)2 were carried-out towards an efficient, low cost, and an environmentally friendly manufacturing approach for high-efficiency perovskite solar cells. The efficient MAyFA1−yPbI3−xBrx perovskite films were successfully realized by sequential dip-coating immersed in MABr and FAI mixed solution of Pb(NO3)2 layer deposited over a ZnO covered c-TiO2 bilayer substrate, in which the four-types of MABr/FAI proportions were investigated to modulate the cationic and anionic ligands such as MA/FA and Br/I components in formation of MAyFA1−yPbI3−xBrx perovskite structures. Although the characteristics of these MAyFA1−yPbI3−xBrx perovskite films were significantly affected by varying MABr/FAI molar ratios, the MAyFA1−yPbI3−xBrx perovskite films prepared with the 0.18-MABr/FAI presented the better light absorption efficiency, higher perovskite conversion factors, superior surface morphology, and better crystallinity with the appropriate Br insertion. The fabricated PrSCs devices with MAyFA1−yPbI3−xBrx perovskite films with 0.18-MABr/FAI exhibited a notable PCE value of 12.6% with high photocurrent of ~ 24 mA cm−2 and high photovoltage of 0.98 V, even it has a rather low fill factor of 0.54, providing efficient operational stability without any significant loss in photovoltaic performance for 500 h.