Enhancement of the Photoluminescence of Cs2AgBiBr6 Double Perovskite Film via Grain Size Regulation

Lead-free double halide perovskite, Cs2AgBiBr6, which exhibits better stability and lower toxicity than lead counterparts, has been considered as promising alternative for optoelectric application. However, intrincially indirect bandgap of Cs2AgBiBr6 has been a hindrance to be used as light-emitter. Recently it was reported that electron-phonon coupling can be weakened by decrasing dimenson of perovskite emitters.<br/>Here, we effectively tackled low PL intensity issue by decreasing grain size by synergistic control of annealing temperature and additive mixing into antisolvent. PL intensity from double halide perovskite film has been doubled at 100nm-sized homogenous grain compared to control smaple with larger grain size(~300nm). We anticipate these techniques would pave the way of Cs2AgBiBr6 as new candidates for lead-free light-emitters.