Efficient eco-friendly light-emitting diodes enabled by lead-free cesium manganese bromine with superior luminescence

Abstract

Metal halide perovskites have opened up a frontier in light-emitting diodes (LEDs) by virtue of their superior optoelectronic performances. Nevertheless, concerns regarding the potential lead toxicity and environmental instability impeded their commercial deployment. Herein, a lead-free perovskite-inspired cesium manganese bromine (Cs3MnBr5) material is presented with a remarkable photoluminescence quantum yield of 90.2% and good environmental stability to fabricate eco-friendly LEDs. The Cs3MnBr5 powders synthesized by the facile wet grinding method exhibit industrial scalability with yields of 81.2% and demonstrate an intense green fluorescence that originates from the d–d transition of Mn2+ ion. Moreover, a thermal evaporation technique combined with post-annealing process is employed to fabricate electroluminescent Cs3MnBr5 films that show improved film morphology with less defect state densities and enhanced luminescence properties. Based on the optimized Cs3MnBr5 films, efficient green-emitting LEDs are demonstrated with a peak external quantum efficiency of 1.63% and a half-lifetime of 86 min. This work showcases a promising pathway for the development of efficient lead-free perovskite LEDs.