Dual-function ligand surface control to achieve high efficiency and brightness perovskite quantum dots LED devices

Metal halide perovskite quantum dots (QDs) have significant potential for application in light-emitting diodes (LED) owing to their superior optical properties. However, the dynamic instability of traditional oleic acid/amine ligands has a considerable impact on the optical and chemical properties of the surface. Additionally, one of its insulating qualities restricts the practical application of electroluminescent devices. In this case, the dual-function ligand DDA-MeS can passivate surface defects while also stabilizing chelation on QDs surface. As a result, the electrical performance of green QDs-LED devices is greatly enhanced, the external quantum efficiency is raised to 10.18%, the maximum brightness is also boosted to 8025 cd/m2, and the turn-on voltage is decreased to 2.5 V. This work also provides a novel strategy for the development of green LED devices with dual-function ligands that can be highly effective and bright. •CsPbBr3 QDs synthesized by thermal injection of bifunctional ligands with S=O and quaternary ammonium groups DDA-MeS modification.•The modified QDs exhibit reduced defect density, and enhanced PLQY and carrier mobility.•High-efficiency perovskite LED based on dual-function ligand modification with EQE of 10.18% and luminance of 8025 cd/m2 is fabricated.