Buried Interface Modification for Efficient FAPbI3 Perovskite Modules by Full Blade-Coating Process

Large area, dense, and uniform SnO 2 films with fewer defects are essential for high-quality perovskite films and efficient n-i-p typed perovskite modules. In this respect, based on the self-synthesized SnO 2 nanoparticles (NPs) 4,4′-bipyridine is introduced as a multifunctional interface modifier at the SnO 2 /perovskite interface. Both experimental and DFT calculation results reveal that, the incorporation of 4,4′-bipyridine can simultaneously passivate interfacial defects from the SnO 2 surface and perovskite bottom surface. Moreover, it can also facilitate charge carrier transportation. Based on blade-coating technique for large area perovskite modules, this strategy significantly enhances the interfacial quality of large-area SnO 2 films and crystal quality of large-area perovskite layers. As a result, the champion small-area cell (0.076 cm 2 ) presents the efficiency of 25.75% while the minimodule (22.9 cm 2 aperture area) exhibits the efficiency of 23.50% with a certified efficiency of 22.70%. Both small-area devices and modules exhibited excellent operation and thermal stabilities, demonstrating that this interface treatment is a promising approach for large-scale production of high-efficiency perovskite modules.