A Highly Tolerant Printing for Scalable and Flexible Perovskite Solar Cells

Abstract Homogeneity and stability of flexible perovskite solar cells (PSCs) are significant for the commercial feasibility in upscaling fabrication. Concretely, the mismatching between bottom interface and perovskite precursor ink can cause uncontrollable crystallization and undesired dangling bonds during the printing process. Herein, methylammonium acetate, serving as ink assistant (IAS) can effectively avoid the micron‐scale defects of perovskite film. The in situ optical microscope is applied to prove the IAS can inhibit the colloidal aggregation and induce more adequate crystallization growth, thus avoiding the micron‐scale defects of pinholes and intergranular cracking. Concurrently, 4‐chlorobenzenesulfonic acid is introduced into the electrode surface as a passivation layer to restore the deep traps at perovskite interface in nano‐scale. Finally, the target flexible devices (1.01 cm²) deliver a superior efficiency of 18.12% with improved air atmosphere stability. This multi‐scale defect repair strategy provides an integrated design concept of homogeneity and stability for scalable and flexible PSCs.