Abstract: Colloidal quantum dots (QDs) are promising emissive materials for optoelectronic devices owing to their tunable emission wavelength, high color purity, and solution processability. Quantum dot light-emitting diodes (QLEDs), an important complementary technology to organic light-emitting diodes, have demonstrated considerable potential in display applications. However, the inherent toxicity of conventional Cd- and Pb-based QDs has driven the development of heavy-metal-free QD systems. Currently, heavy-metal-free blue QLEDs still lag significantly behind their red and green counterparts in device efficiency and operational stability, representing a critical bottleneck to their practical application. To address this issue, ZnSeTe QDs have attracted significant research interest due to their tunable bandgap and excellent blue emission properties. In this work, a comprehensive review of ZnSeTe QDs is provided. Firstly, their nucleation and growth mechanisms, as well as typical synthesis methods are introduced, and the key factors affecting their optical properties are discussed. On this basis, various performance optimization strategies, including band engineering, surface etching, shell passivation, and ligand regulation are systematically summarized. Furthermore, electroluminescence mechanisms of QLEDs and recent progress on the application of ZnSeTe QDs in blue-emitting devices are reviewed. Finally, the current challenges, such as low emission efficiency, limited device lifetime, and charge injection imbalance are discussed, and potential future development directions are proposed.

Key words: blue quantum dot, quantum dot light-emitting diode, ZnSeTe, core-shell engineering, ligand engineering, review