Multifunctional Aerogel Mediated Perovskite Crystallization Toward Self‐Healable and Eco‐Friendly Solar Cells

ABSTRACT Solution‐processed perovskites conventionally crystallize through defective, highly coordinated iodoplumbate species, which generate abundant intrinsic defects and consequently limit the performance of perovskite solar cells (PSCs). Herein, a multifunctional cross‐linking poly(acrylic acid)/poly (4‐vinylpyridine) (PAA‐P4VP) aerogel is employed to regulate perovskite crystallization. Benefiting from its cross‐linked architecture and strong multidentate interactions with perovskite constituents, the aerogel redirects the crystallization pathway toward rapid nucleation and slow crystal growth, yielding uniform perovskite grains with relieved lattice strain and effectively passivated undercoordinated defects. Embedded at grain boundaries, the aerogel reduces the Young's modulus of the perovskite film and imparts self‐healing capability, leading to significantly enhanced mechanical robustness. As a result, the aerogel‐modified PSCs deliver a champion power conversion efficiency of 26.50% on rigid substrates and 24.95% on flexible ones. Notably, the flexible devices maintain over 85% of their initial efficiency after 10 000 bending cycles at a 5 mm curvature radius. Furthermore, lead leakage from PSCs is markedly suppressed owing to the improved water resistance and ultrahigh lead adsorption capacity of the incorporated aerogel (up to 642 mg/g).