84% efficiency improvement in all-inorganic perovskite light-emitting diodes assisted by a phosphorescent material.

A novel mixed perovskite emitter layer is applied to design all-inorganic cesium lead halide perovskite light-emitting diodes (PeLEDs) with high electroluminescence (EL) performance, by combining CsPbBr with iridium(iii)bis[2-(4',6'-difluorophenyl)pyridinato-N,C']-picolinate (FIrpic), where FIrpic is a phosphorescent material with very high internal quantum efficiency (IQE) approaching 100%. The CsPbBr:FIrpic PeLEDs show a maximum luminance of 5486 cd m, and an external quantum efficiency of 0.47%, which are 1.