A Facile Strategy to Suppressing Impurity Phase in Perovskite Wet Films for Efficient and Stable Photovoltaics

Abstract Perovskite solar cells are among the most promising candidates for the next generation of photovoltaic technology. However, the heterogeneous nature of mixed halide perovskites as ionic crystals raises challenges to their photovoltaic performance and long‐term stability. Herein, a functional molecule, named 2‐amino‐4‐trifluoromethylpyridine (2A4TP), is introduced as an inhibitor of impurity phases in perovskite wet films, enabling the formation of optically active pure phase (α‐phase) perovskites at room temperature. Meanwhile, reducing aggregation barrier for perovskite colloidal particles contribute to accelerate perovskite nucleation rate. Ultimately, the resulting uniform perovskite films afford to the optimized perovskite solar cells (0.09 cm 2 ) exhibited a champion efficiency of 24.59% along with superior thermal and operational stability. Finally, 30x30 cm 2 modules fabricated in this way delivers an impressive efficiency of 16.12% (with an aperture area of 655.2 cm 2 ), demonstrating the large‐area compatibility of the strategy.