Morphology control towards bright and stable inorganic halide perovskite light-emitting diodes

Abstract

The effect of morphology control on the performance of inorganic cesium lead halide based green perovskite light-emitting diodes (PeLEDs) was analyzed. PeLEDs were prepared using two different formulation approaches: (1) the solution was prepared by dissolving CsPbBr₃ powders in dimethyl sulfoxide (DMSO), and (2) the precursor solution was formulated by dissolving CsBr and PbBr₂ powders with different molar ratios of CsBr to PbBr₂ in DMSO. A peak luminance of 4590 cd m⁻² was obtained for the PeLEDs prepared with CsPbBr₃-solution, which is 48 and 12 times higher than that of the optimized PeLEDs fabricated using CsBr/PbBr₂ precursor solutions with different molar ratios of CsBr to PbBr₂ of 2 : 1 and 1 : 1. Our results reveal that the morphology and control of excess Pb atoms in the perovskite emitting layer play an important role in modulating the current losses and the radiative decay rate, which were optimized in this work for attaining efficient operation of the PeLEDs.