Improved Charge Collection in Highly Efficient CsPbBrI2 Solar Cells with Light-Induced Dealloying

Halide dealloying in CsPbBrI2 perovskite solar cells proves to be critical in achieving high performance. This dealloying occurs under steady illumination and is a reversible process, suggesting transitions between equilibrium states under dark and illuminated environments. Through decoupling charge collection in the electron- and hole-transporting layers, our photoluminescence, X-ray diffraction, and solar cell device characterization results suggest that the light-induced halide dealloying improves hole collection in solar cells, resulting in increased efficiency (9.2% +/- 0.64 on average with a champion power conversion efficiency of 10.3%). Our results provide deeper insights on the impact of dealloying on perovskite solar cell performance and highlight the growing potential of all -inorganic perovskite solar cells.