Two-Step Sequential Blade-Coating of High Quality Perovskite Layers for Efficient Solar Cells and Modules

Although perovskite solar cells have achieved efficiency over 25%, the scalable fabrication of high efficiency and stable large perovskite solar modules is still a big challenge. To date, various up-scaling methods have been developed to deposit large area perovskite films, but most of them are mainly based on the MAPbI3 perovskites, few on the more stable FA-based perovskites. Here, two-step sequential blade-coating is employed for the scalable fabrication of FA-based perovskite solar cells from ~0.1 cm2 devices to 100 cm2 modules. It is found that a non-volatile solvent having strong coordination and low solubility with PbI2 is beneficial for self-formation of regular nano-porous structured PbI2 films through the blade-coating. This continuous porous structure is extremely important for the PbI2 films to be effectively converted to the black phase perovskites. Further combining with proper perovskite seed-assisted growth to improve the crystallinity, it achieves a champion efficiency of 20.49% for 0.16 cm2 devices, an efficiency of 16.54% for 5×5 cm2 perovskite solar modules, and an efficiency of 13.32% for 10×10 cm2 modules, respectively and all with outstanding stability. This indicates the great potential of two-step sequential printing of perovskite films in scalable production.