Modulating Growth Kinetics and Defect Passivation in Ambient‐Air Evaporation‐Spray Deposition Enables Efficient and Stable Rigid/Flexible Perovskite Solar Cells

Evaporation‐spray technique renders perovskites highly compatible with large‐scale manufacturing. However, the rapid reaction between organic halides and lead iodide induces the accumulation of film defects, rendering the fabrication of high‐quality perovskite films a formidable challenge. To address this critical bottleneck, this study proposes a multifunctional doping strategy based on acetylthiocholine chloride (ATC), which enables the synergistic modulation of the crystalline growth and defect passivation of perovskite films. By virtue of covalent coordination between carbonyl moieties and Pb 2+ , the requirement for intermediate phase transitions in perovskites is eliminated, thereby facilitating complete precursor conversion and decelerating crystal growth. Meanwhile, quaternary ammonium cations and chloride ions efficiently fill the vacancies of organic cations and halide ions, passivate film defects, and markedly suppress the segregation of bromide‐rich/iodide‐rich phases. Ultimately, the resultant perovskite solar cells achieve a power conversion efficiency (PCE) of 22.68%. Moreover, the devices retain 80.35% of their initial efficiency following 1000 h of continuous maximum power point (MPP) tracking tests. The mini‐module with an active area of 63.7 cm 2 achieves a PCE of 17.48%, whereas the flexible devices attain a record‐high PCE of 20.13%.