Illumination Durability and High-Efficiency Sn-Based Perovskite Solar Cell under Coordinated Control of Phenylhydrazine and Halogen Ions

The organic-inorganic hybrid Sn-based perovskite has attracted extensive attention because of its more suitable band gap and environmentally friendly characteristics, but the natural oxidization of Sn2+ makes for unsatisfactory illumination stability and efficiency in solar cells. Here, we successfully proved that the synergistical introduction of phenylhydrazine cation (PhNHNH3+) and halogen anions (Cl– and Br–) could substantially improve the illumination stability of FASnI3 (FA stands for NH2CH = NH2+) through the combination of experiments and theoretical calculations. The resultant device achieved a power conversion efficiency of 13.4% (certified 12.4%) with striking long-term durability; i.e., the optimized device maintained 82% of the original efficiency over 330 h under AM1.5G one-sun illumination. This method provides a universal way for improving the illumination stability and efficiency of Sn-based perovskites.