Efficient, operation-stable green ZnSeTe quantum dot-light-emitting diodes: Impacts of shell dimension and Al incorporation

초록

ZnSeTe quantum dots (QDs) have emerged as promising alternative electroluminescent blue and green emitters to conventional InP-based QDs. Despite recent advancements demonstrating highly efficient blue and green ZnSeTe-based QD-light-emitting diodes (QLEDs), their operational stability remains insufficient for commercial applications. We develop highly efficient and stable green quantum dot-light-emitting diodes (QLEDs) by carefully engineering the shell structure of ZnSeTe quantum dots (QDs) and incorporating aluminum (Al). ZnSeTe cores with precisely tunable green emission are synthesized, and ZnSe inner shell thickness is systematically optimized to enhance electron wavefunction delocalization toward suppression of nonradiative recombination. Additionally, introducing Al into ZnS outer shell is found to significantly improve the thermal stability of QDs by forming an effective Al oxide barrier against oxidative degradation. Optimized Al-incorporated green QLEDs achieved an external quantum efficiency of 19.6 %, matching state-of-the-art performance, while demonstrating outstanding operational stability with a half-lifetime of 4189 h at 1000 cd/m2. These results emphasize that meticulous heterostructure design combined with controlled Al incorporation provides a robust pathway toward high-performance, commercially viable green QLEDs.

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