Te-alloyed ZnTeSe quantum-dot interlayer enables high-efficiency all-inorganic InP QLEDs

All-inorganic quantum dot (QD) light-emitting diodes (QLEDs) are promising for stable electroluminescent applications; however, their performance is often limited by inefficient hole injection and nonradiative recombination originating from the energy-level mismatch between inorganic metal oxide hole transport layers (HTLs) and QD emissive layers (EMLs). Herein, we demonstrate high-performance all-inorganic indium phosphide (InP) QLEDs by introducing wide-bandgap tellurium-alloyed zinc selenide (ZnTeSe) QDs as an interfacial layer between the HTL and the InP EML. The ZnTeSe QD interlayer enables simultaneous passivation of interfacial defects, suppression of electron leakage, and regulation of hole injection. Owing to its shallow conduction band minimum, ZnTeSe mitigates electron trapping at defect states in NiMgOx and suppresses fluorescence quenching in the InP EML, while Te-induced localized states modulate the valence band structure to facilitate hole transport into the EML. As a result, the external quantum efficiency is increased from 0.14% to 6.7%, and the maximum luminance is enhanced from 155 to 6657 cd m−2. This work underscores the importance of interfacial electronic structure engineering and provides an effective strategy for high-efficiency, cadmium-free all-inorganic QLEDs.