Fullerene-Based Electron Transport Layers for Semi-Transparent MAPbBr3 Perovskite Films in Planar Perovskite Solar Cells

In this study, four kinds of structures[6,6]-phenyl-C-61-butyric acid methyl ester (PCBM), PCBM/fullerene (C-60), C-60/bathocuproine (BCP), and PCBM/C-60/BCPwere used as electron transport layers, and the structure, and optical and electronic behaviors of MAPbBr(3) perovskite layers after annealing treatments were observed. The experimental results indicate that PCBM/C-60 bi-layer structure is acceptable for MAPbBr(3) planar perovskite solar cells due to electron step transporting. Low-temperature annealing is suitable for smooth and large grain MAPbBr(3) films. The semi-transparent yellow C-60/PCBM/MAPbBr(3)/PEDOT:PSS/ITO glass-structure solar cells exhibit the best performance with a power conversion efficiency of 4.19%. The solar cells are revealed to be suitable for application in building integrated photovoltaic (BIPV) systems.