Development of High Efficiency, Spray‐Coated Perovskite Solar Cells and Modules Using Additive‐Engineered Porous PbI2 Films

Abstract The development of anti‐solvent free, scalable, and printable perovskite film is crucial to realizing the low‐cost roll‐to‐roll development of perovskite solar cells (PSCs). Herein, large‐area perovskite film fabrication is explored using a spray‐assisted sequential deposition technique. How propylene carbonate (PC) solvent additive affects the transformation of lead halide (PbI 2 ) into perovskite at room temperature is investigated. The result shows that PC‐modified perovskite films exhibit a uniform, pinhole‐free morphology with oriented grains compared with pristine perovskite films. The PC‐modified perovskite film also has a prolonged fluorescence lifetime that indicates lower carrier recombination. The champion PSC devices based on PC‐modified perovskite film realize a power conversion efficiency (PCE) of 20.5% and 19.3% at an active area ( A ) of 0.09 cm 2 and 1 cm 2 , respectively. The fabricated PSCs are stable and demonstrate ≥85% PCE retention following 60 days of exposure to ambient conditions. Furthermore, perovskite solar modules ( A ≈ 13 cm 2 ) that yield a PCE of 15.8% are fabricated. These results are among the best reported for the state‐of‐art spray‐coated PSCs. Spray deposition coupled with a PC additive is highly promising for economical and high‐output preparation of PSCs.