Triple-cation mixed-halide perovskites: towards efficient, annealing-free and air-stable solar cells enabled by Pb(SCN)2 additive

-treated FMC unannealed films present micrometer-sized crystal grains and remarkably high moisture stability. Planar solar cells built upon these unannealed films exhibit a high PCE of 14.09% with significantly suppressed hysteresis phenomenon compared to those of thermal annealing. The corresponding room-temperature fabricated flexible solar cell shows an impressive PCE of 10.55%. This work offers a new avenue to low-temperature fabrication of air-stable, flexible and high-efficiency perovskite solar cells.