Spatially confined chloride passivation for efficient and stable green ZnSeTe quantum-dot light-emitting diodes

ZnSeTe quantum-dot light-emitting diodes (QLEDs) are attractive for cadmium-free green displays, but their performance is limited by surface-trap-assisted nonradiative recombination and interfacial instability. Herein, we report a spatially confined chloride-passivation strategy to improve both the efficiency and operational stability of green ZnSeTe QLEDs. Chloride ions introduced by ZnCl2 passivate under-coordinated surface sites of ZnSeTe quantum dots, while polyvinylpyrrolidone anchors the passivated surface and suppresses field-induced chloride migration. This synergistic treatment reduces the trap-state density in the emitting layer by more than 50% and improves interfacial charge recombination. The optimized devices achieve a maximum external quantum efficiency of 19.8% and a peak luminance of 32 933 cd m−2 at 6.0 V. More importantly, the operational lifetime reaches 188.9 h at an initial luminance of 1000 cd m−2, representing an approximately 60-fold enhancement over the untreated device. These results demonstrate that polymer-confined halide passivation is an effective interfacial engineering approach for efficient and stable cadmium-free ZnSeTe QLEDs.