Stable mixed-cation perovskite light-emitting diodes

Stable mixed-cation perovskite light-emitting diodes (PeLEDs) were fabricated with an inverted structure of indium tin oxide/zinc oxide nanoparticle/polyvinyl alcohol/Cs(0.76)FA(0.24)PbBr(3)/poly(N-vinylcarbazole) (PVK)/molybdenum oxide/aluminum. Cs(0.76)FA(0.24)PbBr(3) with formamidinium cations at a low molar ratio was used as the electroluminescence emitter. A Cs(0.76)FA(0.24)PbBr(3)/PVK bilayer was prepared in one step by treating the Cs(0.76)FA(0.24)PbBr(3) surface with chlorobenzene antisolvent dissolved in 7.5 mg mL(-1) PVK while fabricating the emitting layer by spin coating. The PeLEDs exhibited an improved operational lifetime (the time for the luminance to decay to half of the initial luminance) of 11.7 min at a high initial brightness of 10,000 cd m(-2). The mechanism underlying the increased stability of the PeLEDs was possibly the intrinsic photoluminescence stability of Cs(0.76)FA(0.24)PbBr(3) with reduced traps.