Suppressing Phase Segregation in CsPbIBr 2 Films via Anchoring Halide Ions toward Underwater Solar Cells.

Inorganic CsPbIBr 2 perovskite solar cells (PSCs) have accomplished many milestones, yet their progress has been constrained by ion migration and phase separation. This study explores the modulation of perovskite crystallization kinetics and halide ion migration through chlorobenzene (CB) antisolvent with bis(pentafluorophenyl)zinc (Zn(C 6 F 5 ) 2 ) additive. The photoluminescence and absorption spectra reveal the significantly reduced phase segregaton in CsPbIBr 2 film treated by CB with Zn(C 6 F 5 ) 2 . Moreover, this research analyzes the CsPbIBr 2 film's free carrier lifetime, diffusion length, and mobility using time-resolved microwave conductivity and transient absorption spectroscopy after Zn(C 6 F 5 ) 2 modification. Consequently, the modified CsPbIBr 2 PSCs offer a 12.57% power conversion efficiency (PCE), the highest value among CsPbIBr 2 PSCs with negligible hysteresis and prolonged stability. Furthermore, under 1-m-deep water, CsPbIBr 2 PSCs display a PCE of 14.18%. These findings provide an understanding of the development of phase-segregation-free CsPbIBr 2 films and showcase the prospective applications of CsPbIBr 2 PSCs in underwater power systems.