Ternary solvent engineering incorporating hydrogen bonding for FAPbI₃ perovskite solar cells

This study explores crystallization rate control to improve grain size and surface roughness. Traditional binary solvent engineering has limitations for FAPbI₃ films because of rapid solvent evaporation at high annealing temperatures. Accordingly, this research proposes ternary solvent engineering (TSE) using dimethylformamide (DMF), dimethyl sulfoxide (DMSO), and anisole (AN), which delays crystallization by forming hydrogen bonding. This finding demonstrates that AN, which is typically used as an antisolvent, can be effectively utilized as a PbI₂ precursor solvent. This approach affords larger grain sizes, reduces surface roughness, and improves charge transport, leading to an improvement in PCE from 12.23 % to 13.85 % by enhancing the fill factor. The results of this study suggest that TSE with AN can significantly enhance the performance of PSCs, providing a new pathway for efficient perovskite film fabrication.