CO2 Laser Crystallization in Ambient for Highly Efficient FAPbI3 Perovskite Solar Cells

Abstract Metal halide perovskite solar cells have achieved tremendous progress and have attracted enormous research and development efforts since the first report of demonstration in 2009. Due to fabrication versatility, many heat treatment methods can be utilized to achieve perovskite film crystallization. Herein, 10.6 µm carbon dioxide laser process is successfully developed for the first time for perovskite film crystallization. In addition, this is the first time formamidinium lead triiodide solar cells by laser annealing under ambient are demonstrated. The champion cell produces a power conversion efficiency of 21.8%, the highest for laser‐annealed perovskite cells. And this is achieved without any additive, passivation, or post‐treatment.