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Two-step sequential blade-coating of high quality perovskite layers for efficient solar cells and modules

Zhang, Junwen, Bu, Tongle, Li, Jing, Li, Hengyi, Mo, Yanping, Wu, Zhengli, Liu, Yifan, Zhang, Xiao-Li, Cheng, Yi-Bing, Huang, Fuzhi
Journal of materials chemistry A 2020 v.8 no.17 pp. 8447-8454
crystal structure, solar cells, solubility, solvents
Although perovskite solar cells have achieved an 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 and a 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 blade-coating. This continuous porous structure is extremely important for the PbI₂ films to be effectively converted to black phase perovskites. Upon further combining with appropriate perovskite seed-assisted growth to improve the crystallinity, 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 are achieved, all with outstanding stability. This indicates the great potential of two-step sequential printing of perovskite films in scalable production.