Bidirectional Synergistic Crystallization Strategy for Regulating Growth Kinetics Toward Highly Efficient and Stable Perovskite Solar Cells

Abstract Crystalline quality is paramount for the performance and stability of perovskite films and devices. By regulating the nucleation and growth processes, it is possible to significantly enhance the crystalline quality. This work introduces a bidirectional synergistic crystallization strategy (BSC strategy) that synchronizes the crystallization kinetics across both the top and bottom surfaces of the perovskite film, thereby enhancing film quality and boosting the efficiency of perovskite solar cells (PSCs). Employing time‐resolved optical characterization techniques, it is demonstrated that the BSC strategy effectively mitigates the dissolution–recrystallization cycle of the perovskite nuclei and grains during annealing, accelerates the evaporation of residual solvents at the bottom of the perovskite film, and suppresses void formation at the buried interface. Depth‐resolved grazing‐incidence wide‐angle scattering analyses further confirm that the BSC strategy improves the crystalline quality of the perovskite film, promotes oriented growth, and minimizes internal residual strains caused by uneven growth dynamics. This approach results in a champion device efficiency of 24.98%, with the low voltage deficit of 360 mV. Moreover, device stability is markedly enhanced, after 1000 h of continuous light exposure, the efficiency remains over 91% of the initial value.