Benzoic acid mediating ligand exchange of CsPbBr3 nanoplates for high performance blue perovskite LED

The performance of CsPbBr3-based blue perovskite light-emitting diodes (PeLEDs) is compromised due to the intrinsic properties of essential ligands, which hinder their application in full-color displays and lighting. In this study, CsPbBr3 nanoplates (NPLs) with high efficiency and exceptional stability have been synthesized by benzoic acid (BA) mediating ligand exchange. This innovative method employs BA to promote protonation and eliminate excess long-chain ligands. Subsequent in situ ligand exchange with dimethyl didodecylammonium bromide substituting for the long-chain ligands results in a notable enhancement of photoluminescence quantum yield (from 23% to 78%) and stability. As a result, CsPbBr3 NPLs based PeLEDs exhibit efficient pure blue electroluminescence with an external quantum efficiency of 1.10% at 468 nm, an International Commission on Illumination coordinate of (0.128, 0.099), and enhanced spectral stability.