Strain Modulation in ZnSeTe Spherical Quantum Well Quantum Dots for Efficient Blue QLEDs
Chenglin Lai1, Sheng Cao1, Yi Liang1
1School of Physical Science and Technology, State Key Laboratory of Featured Metal Materials and Life-cycle Safety for Composite Structures, Guangxi University, Nanning 530004, China.
Abstract:
Eco-friendly ZnSeTe quantum dots (QDs) have attracted significant attention in blue quantum dot light-emitting diodes (QLEDs) due to their tunable bandgaps and superior blue emission properties. However, conventional ZnSeTe/ZnSe core-shell structures suffer from substantial lattice mismatch at the interface, resulting in interface strain and defect formation that severely limit the device luminescence properties. Herein, a spherical quantum well (SQW) architecture (ZnSe/ZnSeTe/ZnSe) is employed to regulate strain and optimize luminescence by tuning the thickness of the ZnSe inner shell. The results demonstrate that a moderate ZnSe inner shell thickness effectively alleviates interface strain, significantly reduces defect density, suppresses nonradiative recombination, and markedly enhances exciton radiative efficiency, achieving a photoluminescence quantum yield of 91%. Furthermore, blue QLEDs fabricated by using the optimized QDs exhibit excellent electroluminescent performance with an external quantum efficiency of 16.7%. This work provides valuable theoretical insights and practical guidance for the rational design of cadmium-free blue quantum dots and the advancement of high-performance QLED devices.
