Synergistic Chloride Passivation and Inorganic Shell Confinement in ZnMgO Nanoparticles for Efficient and Stable Blue ZnSeTe QLEDs

Blue ZnSeTe quantum dot light-emitting diodes (QLEDs) are promising candidates for next-generation displays, but their efficiency and stability lag behind those of red and green devices. Herein, we report a synergistic modification strategy that integrates halide ion passivation with inorganic shell confinement to boost the performance of blue ZnSeTe QLEDs. Chlorine ions (Cl^-) were employed to passivate oxygen vacancy defects on the surface of ZnMgO nanoparticles, followed by encapsulation with a Mg(OH)₂ inorganic shell to stabilize Cl^- ions. This approach significantly suppresses nonradiative recombination and exciton quenching. As a result, the blue ZnSeTe QLEDs with the engineered ZnMgO nanoparticles exhibit a high external quantum efficiency of 17.5% and a peak luminance of 13670 cd m^-2 at 6.0 V, alongside a 4.6-fold increase in operational lifetime compared to the untreated ones. This work provides a promising pathway to enhance the efficiency and longevity of blue QLEDs, narrowing the performance gap across the full color spectrum.