High-Performance Planar-Heterojunction Solar Cells Based on Ternary Halide Large-Band-Gap Perovskites

High-performance planar-heterojunction (PHJ) solar cells based on large band-gap (1.70-1.83 eV) perovskites are demonstrated. By incorporating Cl- into the MAPb(I1-YBrY)3, the crystallinity and homogeneity of the solution-processed perovskite thin films are much improved, which results in an increased charge carrier diffusion length from approximate to 160 nm to approximate to 700-800 nm. This enhancement leads to a high power conversion efficiency (PCE) of 10% in the low-temperature solution-processed PHJ devices.