Crystallization and Defect Regulation in Sn–Pb Perovskite Solar Cells via Optimized Anti-Solvent Passivation Strategy

Low bandgap tin–lead halide perovskite (PVSK) presents promising opportunities for high-performance solar cells. However, the randomly crystallized Sn–Pb PVSK with a tin-rich surface is easily oxidized, leading to high-level p-type doping, which hinders the performance enhancement of the solar cell devices. Herein, an efficient anti-solvent passivation strategy to regulate defect, crystallization, and energy conversion performance based on anti-solvents composed of chlorobenzene, isopropanol, and methylammonium chloride (MACl) is proposed. It is shown that the Sn–Pb PVSK film gets more moderate and order, with less PbI 2 and more α-phase PVSK formed. Furthermore, it is revealed that the surface of the as-processed film is Pb-rich, demonstrating a decrease in the surface p-type concentration, which is more suitable for the photoelectric conversion enhancement of the inverting device. Finally, the MACl-assisted post-treated Sn–Pb PVSK invert solar cells exhibit a high current density of 26.49 mA cm −2 with a open-circuit voltage of 0.70 V and a power conversion efficiency of 16.05%. The modified anti-solvent process fuses the advantage of additive and anti-solvent engineering for growing highly crystallized hybrid tin-lead halide PVSK for photovoltaic devices.