A Study of Inverted-Type Perovskite Solar Cells with Various Composition Ratios of (FAPbI₃)1-x(MAPbBr₃)x.

This work presents mixed (FAPbI₃)1-x(MAPbBr₃)x perovskite films with various composition ratios, x (x = 0-1), which are formed using the spin coating method. The structural, optical, and electronic behaviors of the mixed (FAPbI₃)1-x(MAPbBr₃)x perovskite films are discussed. A device with structure glass/indium tin oxide (ITO)/poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS)/mixed perovskite/C60/BCP/Ag was fabricated. The mixed perovskite film was an active light-harvesting layer.

PEDOT: PSS was a hole transporting layer between the ITO and perovskite. Both C60 and bathocuproine (BCP) were electron transporting layers. MAPbBr₃ was added to FAPbI₃ with a composition ratio of x = 0.2, stabilizing the perovskite phase, which exhibited a uniform and dense morphology. The optimal device exhibited band matching with C60, resulting in a low series resistance (Rsh) and a high fill factor (FF). Therefore, the device with composition (FAPbI₃)1-x(MAPbBr₃)x and x = 0.2 exhibited outstanding performance.