All-solution-processed CsPbBr3 perovskite quantum dot light-emitting diodes passivated by phenylethylammonium bromide salt

All-inorganic CsPbBr3 perovskite quantum dots have wide application in the field of light-emitting diodes due to their excellent optoelectronic properties (such as high color purity, high photoluminescence quantum yield and solution processability, etc.). However, the performance of CsPbBr3 quantum dot light-emitting diodes is often hindered by the long-chain (oleic acid and oleylamine) insulating ligands on the surface of quantum dots. Herein, we introduce a solid-phase ligand exchange method to ameliorate the performance of perovskite quantum dot light-emitting diodes by passivating CsPbBr3 quantum dot films with phenylethylammonium bromide. As a result, the introduction of phenylethylammonium bromide effectively removes the long-chain ligands on the surface of quantum dot films, and passivates the bromide vacancy defects. Furthermore, the maximum luminance and external quantum efficiency of the all-solution-processed device increase from 570 cd m- 2 to 0.09 % to 1807 cd m- 2 and 0.27 %, respectively. This work provides a simple and feasible method for the development of lowcost all-solution-processed perovskite quantum dot light-emitting diodes.