Surface Lattice Engineering Enables Efficient Inverted Perovskite Solar Cells

Abstract State‐of‐the‐art inverted perovskite solar cells (PSCs) have exhibited considerable promise for commercialization due to their prospective stability. However, the intricate crystallization of halide perovskite, especially for multi‐component perovskites, not only distorts the surface lattice from its ideal form but also introduces numerous unsaturated dangling bonds to form surface defects, which can easily lead to reduced stability and poor performance. Herein, a surface lattice engineering is developed by coupling surface unsaturated ions and regulating ion bonding lengths/angles to achieve efficient and stable inverted PSCs. The renovated surface lattice not only eliminates shallow/deep level defects on the surface of perovskite, but also enhances photo/thermal stability of the materials. Moreover, the surface lattice engineering contributes to uniform potential surface, and improves energy‐level alignment at the interfaces of the perovskite and C 60 carrier transport layer, enhancing charge carrier extraction and transportation. Finally, the champion PSC delivers an impressive efficiency of 25.82% (certified 25.5%). Moreover, these PSCs exhibit excellent operational stability, retaining 94% initial efficiency after more than ≈1 000h maximum power point test.