Liu, Yang, Zhang, Wu, Wei, Guo, Arumugam, Hu, Liu, Lin, Schropp, Mai (2020) Tailoring C60 for Efficient Inorganic CsPbI2 Br Perovskite Solar Cells and Modules Advanced materials (Deerfield Beach, Fla.) 32(8) e1907361


Although inorganic perovskite solar cells (PSCs) are promising in thermal stability, their large open-circuit voltage (VOC ) deficit and difficulty in large-area preparation still limit their development toward commercialization. The present work tailors C60 via a codoping strategy to construct an efficient electron-transporting layer (ETL), leading to a significant improvement in VOC of the inverted inorganic CsPbI2 Br PSC. Specifically, tris(pentafluorophenyl)borane (TPFPB) is introduced as a dopant to lower the lowest unoccupied molecular orbital (LUMO) level of the C60 layer by forming a Lewis acidic adduct. The enlarged free energy difference provides a favorable enhancement in electron injection and thereby reduces charge recombination. Subsequently, a nonhygroscopic lithium salt (LiClO4 ) is added to increase electron mobility and conductivity of the film, leading to a reduction in the device hysteresis and facilitating the fabrication of a large-area device. Finally, the as-optimized inorganic CsPbI2 Br PSCs gain a champion power conversion efficiency (PCE) of 15.19%, with a stabilized power output (SPO) of 14.21% (0.09 cm2 ). More importantly, this work also demonstrates a record PCE of 14.44% for large-area inorganic CsPbI2 Br PSCs (1.0 cm2 ) and reports the first inorganic perovskite solar module with the excellent efficiency exceeding 12% (10.92 cm2 ) by a self-developed quasi-curved heating method. © 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.