Effect of A-site cations on MAPbBr3 perovskite light-emitting diodes

Abstract Perovskite light-emitting diodes (PeLEDs) have gained widespread acceptance in the field of optoelectronics due to their exceptional performance. In this paper, CsBr was added to MAPbBr3 emissive layer in order to reduce the non-radiative recombination defects of perovskite films. The maximum luminance of the optimized device is 4248 cd/m2, and the maximum external quantum efficiency is 0.44 %, which is 162% and 69% higher than that of the undoped device, respectively. This is primarily attributable to the fact that the incorporation of CsBr into the MAPbBr3 perovskite results in a reduction in the surface roughness of the perovskite film. Meanwhile, CsBr can passivate the internal defects of perovskites and inhibit the defect-assisted non-radiative recombination, thus improving the radiative recombination efficiency and leading to the enhancement of the device’s optoelectronic performance. These results have a positive effect on the further in-depth study of the performance and preparation process of PeLEDs.