Synergistic Surface‐Bulk Induction of Uniform Out‐of‐Plane (100) Orientation for High‐Efficiency Perovskite Solar Cells

ABSTRACT Perovskite thin films featuring out‐of‐plane oriented (100) crystallographic facets are pivotal for advancing the efficiency and stability of perovskite solar cells, owing to their superior charge transport properties and reduced deep‐level defect density. However, conventional single‐strategy modification approaches are typically constrained by limited control over crystal orientation and spatially heterogeneous orientation distribution, hindering the full exploitation of such beneficial facets. Herein, we present a surface‐bulk synergistic induction strategy that overcomes the limitations of single modification approaches, effectively promoting directional grain alignment and cooperatively guiding ordered out‐of‐plane growth during thermal annealing. Benefiting from the successful fabrication of a perovskite film with a uniform and predominant preferred orientation, the inverted perovskite solar cells achieve a champion power conversion efficiency of 26.98% (certified 26.41%). Furthermore, the homogeneous texture and high intrinsic stability of the (100) facets enable the devices to retain 93.5% of their initial PCE after 1000 h of operational stability testing. This strategy effectively tackles the technical constraints of precursor solution regulation and solid‐state surface treatment, offering a novel research model for the precise modulation of perovskite thin film crystal facets and the secondary growth of polycrystalline thin films.