Blue-Emitting ZnSe(Te) Quantum Dots and Light-Emitting Diodes

Zn-based quantum dots (QDs) have been regarded as the most promising Cd-free candidates for blue-emitting applications. ZnSe QDs exhibit an ultra-narrow full width at half maximum (FWHM), high photoluminescence quantum yield (PLQY), and excellent environmental stability, making them ideal for blue-violet emitters. ZnSe/ZnS core-shell structures have achieved a near 100% PLQY, thereby enabling high performance QDs light-emitting diode (QLED) with an external quantum efficiency (EQE) of 13.6% at 443 nm. In order to extend the luminescence range for blue display, ZnSeTe QDs has been developed by doping Te ions into ZnSe. Currently, ZnSeTe QLEDs have achieved a maximum EQE of 24.7% at 460 nm, comparable to state-of-the-art Cd-based QLEDs, and a half-lifetime of nearly 30 000 h (@100 cd/m²), demonstrating exceptional commercial potential. This review focuses on blue-emitting ZnSe(Te) QDs, offering a comprehensive overview of recent advances. It presents a systematic discussion on ZnSe(Te) QDs, beginning with material properties and synthesis methods, following by the optimization strategies. Subsequently, the construction of LED devices is analyzed through improvements in both the emitting layer and carrier transport layers. Finally, the challenges in the development of ZnSe(Te) QLEDs are identified, and potential solutions are proposed, aiming to promote further advancements and accelerate their commercialization.