Surface Defect Passivation Enables Efficient and Stable Perovskite Quantum Dot Light-Emitting Diodes

Perovskite quantum dots have garnered significant interest in light-emitting diode applications, attributed to their remarkable optoelectronic properties. However, during the purification process involving polar solvents, the detachment of ligands from the quantum dot surface often induces crystal defects and reduces luminescence performance. This paper uses a two-site quantum dot surface defect passivation strategy based on the ligand molecule N-PS to stabilize the dynamic surface. N-PS greatly reduces the surface defects of quantum dots through the strong anchoring of (CH₂)₂N(CH₃)⁺ and SO₃⁻ functional groups. The electroluminescence performance of the corresponding quantum dot light-emitting diode is greatly improved, with the external quantum efficiency increased to 10.07% and the turn-on voltage reduced to 2.5 V. These QLEDs exhibit excellent optoelectronic properties, providing new insights into tuning the surface chemistry of perovskite quantum dots to achieve surface ligand design criteria for high-performance LEDs or other optoelectronic devices.