Homologous Fluorination Enables Asymmetric Dynamic Interfacial Coupling for Efficient and Sustainable Blade-Coated Perovskite Solar Cells.

Self-assembled monolayers (SAMs) are indispensable hole-transport interfaces in inverted perovskite solar cells (PSCs), yet conventional co-assembly strategies based on symmetric strong interactions often suffer from excessive aggregation, limited adaptability, and insufficient interfacial robustness. Here, we developed a homologous fluorination-enabled asymmetric interfacial interaction strategy by integrating fluorinated SAM molecule [2-(3,6-difluoro-9H-carbazol-9-yl)ethyl]phosphonic acid (F-2PACz) with perfluorooctanoic acid (PFOA) as a dynamic co-assembly modulator. Unlike conventional symmetric systems, PFOA formed weak fluorine-mediated interactions with F-2PACz to regulate SAM assembly and improve interfacial coverage, while establishing stronger hydrogen-bonding and coordination interactions with the perovskite layer for defect suppression and Pb2 + immobilization. This asymmetric interaction hierarchy optimized buried interface quality, promoted charge extraction, and enhanced device stability. Consequently, blade-coated inverted PSCs achieved a champion efficiency of 24.72% and retain 97.7% of their initial efficiency after 1140 h maximum power point tracking under ISOS-L-1I conditions. The strategy was compatible with perovskites of different bandgaps, enabling four-terminal all-perovskite tandems with 27.10% efficiency. Moreover, the fluorinated interface achieved a lead sequestration efficiency of 97.4%, mitigating lead leakage. This work establishes asymmetric fluorine-mediated interfacial coupling as a molecular design strategy for efficient, stable, and sustainable inverted PSCs.