Mixed‐Antisolvent Engineering for Crystallization and Defect Regulation in Inverted Perovskite Solar Cells

ABSTRACT The performance of perovskite solar cells (PSCs) remains critically dependent on the quality of the perovskite absorber, which is largely established during the antisolvent‐assisted crystallization process. Single‐antisolvent engineering, however, is often constrained by the fixed physicochemical properties of the chosen solvent, leaving limited flexibility to balance solvent extraction, crystallization modulation, and defect suppression. Herein, we report a physicochemical‐property‐assisted binary‐antisolvent engineering for high‐efficiency inverted PSCs. A series of binary antisolvent combinations were screened by considering key solvent properties, among which the carbon disulfide/anisole (CS 2 :ANI) system delivered the best device performance. Comprehensive chemical, structural, and optical characterizations reveal that the CS 2 :ANI system enables a more coordinated crystallization process by regulating solvent removal and modifying the precursor environment through interactions between CS 2 ‐derived C═N‐containing species and the Pb–I framework. The resulting perovskite films exhibit compact morphology, reduced residual stress, and suppressed defect‐assisted nonradiative recombination. The optimized inverted PSCs achieve a champion power conversion efficiency (PCE) of 26.73% and a steady‐state output efficiency of 26.43%.