柠檬酸配体改善绿光钙钛矿发光二极管发光效率OA

Metal halide perovskite nanocrystals(CsPbX3)have emerged as promising candidate materials for dis-play technologies due to their excellent optoelectronic properties.However,the weak coordination and long-chain structure of conventional ligands,such as oleic acid and oleylamine(OA/OLA),result in surface defects and hin-dered carrier transport,which significantly limit the performance enhancement of perovskite light-emitting diodes(PeLEDs).In this study,a short-chain,strongly chelating citric acid(CA)ligand was introduced.This ligand forms both coordination bonds and hydrogen bonds with the CsPbBr3 surface through its carboxyl(—COOH)and hydroxyl(—OH)functional groups,effectively passivating surface defects of the nanocrystals.Experimental results combined with density functional theory(DFT)calculations demonstrate that the adsorption energy of citric acid ligands is considerably higher than that of traditional OA/OLA ligands.This leads to a more uniform nanocrystal size distribution,significantly enhanced photoluminescence quantum yield(PLQY),and a substantial reduction in the non-radiative recombination rate.Green-emitting PeLEDs based on citric acid-modified CsPbBr3 nanocrystals exhibit excellent electroluminescent performance,achieving a peak external quantum efficiency(EQE)of 13.58％and a peak current efficiency of 42.93 cd/A.This study presents a novel strategy for surface defect engineering of perovskites through cost-effective ligand design,and the multidentate chelating mechanism may be applicable to oth-er optoelectronic devices such as photodetectors and solar cells.