One-Step Spray-Coated All-Inorganic CsPbI<sub>2</sub>Br Perovskite Solar Cells
Yu-Tien Yu, Shun‐Hsiang Yang, Li‐Hui Chou, Itaru Osaka, Xiaofeng Wang, Cheng‐Liang Liu
Abstract
Here, we report a scalable ultrasonic spray deposition under ambient conditions to fabricate a CsPbI2Br-based all-inorganic perovskite thin film for photovoltaic applications. With the cooperated aid of vacuum extraction of the as-fabricated perovskite film and the incorporation of lead(II) acetate (Pb(Ac)2) additive to the precursor solution, the quality of the perovskite film dramatically improved from the filled pinholes between the crystal grain with enhanced perovskite crystallinity. We found that the champion device for the 5% Pb(Ac)2-doped CsPbI2Br perovskite film combined with vacuum extraction achieved the best power conversion efficiency (PCE) of 10.06%, arising from the efficient defect dissipation within the film and the reduction in the charge recombination loss. Simultaneously, the thermal stability was boosted with the incorporation of Pb(Ac)2 after aging at 85 °C for 10 days. We believe that the spray-coating process combined with the optimization of the all-inorganic perovskite film will help in the fabrication of a photoabsorbing layer for the future industrial upscaling of perovskite solar cells.