Rui Li, Dayong Liu, Danning Sun, Junzhe Feng, Mingze Liu, Yang Cao, Xin Zhi, Xiaodong Wang, Yuqi Peng, Hongyan Zhao, Weihua Di, Jie Li, Min Lu
PbSe colloidal quantum dots (CQDs) have emerged as a popular research subject in optoelectronic devices because of their tunable luminescence in the near-infrared (NIR) region. However, intrinsic defects generated during their synthesis make it challenging to obtain chemically stable and highly efficient PbSe CQDs. In this work, we demonstrate an effective passivation strategy using phenethylammonium chloride (PEACl) additives that form a robust Pb-Cl protective layer on the surface of PbSe CQDs. This approach boosts the photoluminescence quantum yield (PLQY) from 25.7% to 46.1% and enhances the air and thermal stabilities of PbSe CQDs. We have successfully fabricated high-performance phosphorescence conversion light-emitting diode (PC-LED) devices based on defect-passivated quantum dots. These PC-LEDs achieve a peak external quantum efficiency (EQE) of 2.88% at a low drive voltage of 2.08 V, demonstrating excellent photoconversion performance and holding significant application potential in the field of nondestructive optical inspection and food quality sensing.