Enhanced Crystallinity with Disappeared Pb⁰-Related Defects Resulted from Optimal Chain Length Alkylamine for...

Achieving high-quality, controllable crystallization of perovskite films is a core challenge in fabricating high-performance solar cells. In this work, the electrostatic potential, electrophilicity, nucleophilicity, and average free-radical index were calculated for a series of alkylamines with different chain lengths. The theoretical calculation results demonstrate that pentylamine reveals both strong nucleophilicity and high stability, showing optimal balance as the prime candidate for regulating crystallization. XPS results revealed that the Pb⁰ peak disappeared, indicating effectively restrained Pb⁰-related defect densities. Ultimately, the modified devices achieved a high efficiency of 23.43% and manifested excellent environmental stability. This work confirms the significant potential of small-molecule additives in addressing the challenge of controllable perovskite crystallization.