Improved Morphology of Wide-Bandgap Perovskite Solar Cells Enabled by Double Anti-Solvent Pb–Halide Bonding Control

Wide-bandgap perovskites (WBPs) are promising for efficient indoor and outdoor photovoltaics, but their film quality is often degraded by surface wrinkles and halide phase segregation, which limit device performance. Here, we demonstrate that precise control of Pb–halide bonding via a double antisolvent treatment effectively suppresses wrinkle formation and mitigates halide phase segregation in WBP films without altering the crystal structure. This approach yields smoother, more uniform films with enhanced optical absorption, photoluminescence, and carrier lifetimes. Among the combinations tested, chlorobenzene (CB) followed by methyl acetate (MeAc) produced the highest performance, achieving power conversion efficiencies of 18.05% under 1 sun and 31% at 1000 lx, outperforming the single antisolvent (CB) process. These results highlight the fundamental link between Pb–halide bonding control and defect suppression and establish double antisolvent processing as a scalable route to high-performance WBP solar cells for diverse illumination environments.