Interface-Driven Multi-Dimensional Regulation of Lead Ion Accumulation and Passivation to Enhance Environmental Stability of Air-Fabricated Perovskite Solar Cells

The interaction between trap states and interface defects exacerbates non-radiative recombination at the interface, reducing the photoconversion efficiency and affecting the long-term stability of perovskite solar cells (PSCs). In this study, it is designed a multifunctional modifier, 4-((cyano(2,4-difluorophenyl)methyl)amino)-5-methyl-1H-pyrazole-3-carboxylate (CDFP-MP), aimed at multi-level regulation of interface defects and perovskite crystallization. The spatial structural features and the synergistic action of its functional groups not only passivate the major charge defects at the perovskite interface caused by lead enrichment to the greatest extent but also exhibit good geometric compatibility with tin oxide, effectively reducing charge localization effects. Through coordination with lead ions in the perovskite, the excessive aggregation and growth of lead iodide during the two-step fabrication process are effectively suppressed, improving the crystallization dynamics of the perovskite and the stability of the interface environment. This leads to a reduction in carrier capture at defect states, enhanced charge transport efficiency, and increased charge diffusion length, resulting in a power conversion efficiency (PCE) of 25.09% for PSCs fabricated in air-based processes. The unencapsulated PSCs maintain 89.08% of the initial PCE after 2100 h at 30±5% humidity. Additionally, the application of CDFP-MP in large-area vacuum-deposited PSCs with air annealing highlights its scalability and commercial potential.