Uniform infrared light field induced rapid crystallization and enhanced stability of perovskite solar cells

Infrared (IR) light has exhibited remarkable efficacy in facilitating the annealing crystallization process of perovskite film. However, the precise mechanisms underpinning the promotional effects of IR remain a subject of ongoing investigation. Herein, we address this critical knowledge gap by presenting a comprehensive investigation into the mechanisms governing IR-induced crystallization and its impact on the performance of perovskite solar cells. Our computational simulations reveal that IR light create a swift, stable, and homogenous annealing environment during the crystallization. The incident light field on the perovskite film surface orchestrates the controlled departure of excess iodide ions from the surface, consequently inducing the formation of iodine vacancies. This transformative process leads to a transition of the surface from a strong p-doped state to a more delicate n-doped state. Furthermore, the application of IR treatment demonstrates a pronounced propensity for facilitating the integration of methylammonium iodide (MAI) into the less compacted PbI2 lattice, thereby expediting the crystallization rate. Remarkably, devices processed within this uniform and stable light field exhibit augmented performance and heightened stability. In summary, our study furnishes invaluable insights into the intricate interplay underlying IR-assisted crystallization in perovskite solar cells. The elucidation of these mechanisms holds significant promise for advancing future industrial-scale fabrication techniques for enhanced perovskite solar cell production.