Regulating Perovskite Film Crystallization <italic> via</italic> Organic Amine Salts for Enhanced Photoelectric Conversion Efficiency and Stability

Currently, photoelectric conversion efficiency (PCE) of perovskite solar cells (PSCs) has reached 27%, yet their industrialization remains constrained by film quality and stability issues in perovskite layers. This study employed butylammonium iodide (BAI) as additive to regulate crystal orientation in perovskite films through retarded crystallization kinetics and induced preferred orientation growth, resulting in significantly enlarged grain sizes and reduced defect densities. Benefiting from the intrinsic high hydrophobicity of organic ammonium salts, optimized films demonstrated enhanced environmental tolerance. Consequently, achieved PCE of rigid devices improved from 22.32% to 23.46% with notably suppressed hysteresis, while that of flexible perovskite solar cells (F-PSCs) improved from 21.51% to 22.26%, confirming the strategy's universality across substrates. Stability tests demonstrated that treatment of perovskite film with BAI led to simultaneous improvements in the environmental stability, thermal stability and light stability of PSCs, as well as the mechanical stability of F-PSCs. This work provides a novel solution for enhancing crystallization control and stability in perovskite films, offering new insights for developing high-performance perovskite photovoltaics with significant industrial application potential.