Core/Shell ZnMgO@MgLiO Electron Transport Layer for High‐Performance Green Quantum Dot Light‐Emitting Diodes Toward Rec.2020 Standard

Quantum dot light‐emitting diodes (QD‐LEDs) are among the most promising candidates for new‐generation displays and solid‐state lighting applications. However, state‐of‐the‐art QD‐LEDs with Rec. 2020 pure‐green emission remain challenging, attributable to the insufficient electron injection resulting in the low exciton formation rate. Herein, novel ZnMgO (ZMO) nanoparticles (NPs) capped with MgLiO (MLO) shells are developed as electron transport layers (ETL) to enhance the performance of green QD‐LEDs. MLO alloyed shells effectively passivate the defect states (such as oxygen vacancy) in ZMO thereby suppressing the interfacial exciton quenching, and elevating the electron injection, thereby improving exciton radiative recombination at a low voltage. As a result, the pure green QD‐LEDs exhibit the luminance of 1 385 780 cd m −2 at the voltage of 7.7 V among the highest reported green QD‐LEDs without light outcoupling technology, an operational lifetime T 95 (time for luminance to drop to 95% of its initial value) of 29 183 h at the initial luminance of 1 000 cd m −2 and remarkable spectral stability. These advances represent one of the best‐performing Rec.2020 pure‐green QD‐LEDs to date, and pave the way toward energy‐efficient QD‐LED displays.