Multiple‐Active‐Site Additives Enable Synergistic Surface Passivation and Defect Healing for High‐Efficiency and Durable Inverted Perovskite Solar Cells

ABSTRACT Crystal quality is essential for high‐performance and stable perovskite solar cells (PSCs). Surface and grain‐boundary defects can induce non‐radiative recombination, while water molecules and high temperatures can degrade perovskite and shorten device lifetime. Dual strategies of defect passivation and interfacial hydrophobicity are crucial for fundamentally boosting device performance. Herein, 12‐Pentafluorophenoxydodecylphosphonic acid (PFPA) is employed as a surface passivator for perovskite films. Its multiple active sites bind under‐coordinated Pb 2+ and fill iodide vacancies, suppressing phase transition, non‐radiative recombination, and extending operational stability. The PFPA‐passivated device delivers a champion PCE of 26.33% (a certified steady‐state efficiency of 25.63% for 300 s maximum power point tracking) and a high V oc of 1.19 V. Simulation studies have shown that PFPA can still effectively passivate at 400 K. At the same time, the adsorption of perovskite and H 2 O is reduced by 25%. After 1032 h of maximum power point tracking (MPPT) in a natural environment, the device still maintains above 90% of its initial efficiency. PFPA also improves both wide‐bandgap perovskite solar cells and perovskite‐silicon tandem solar cells, fully demonstrating its universality. This study has opened up a new avenue for improving the optoelectronic performance and stability of perovskite solar cells.