Quantum dot (QD) light-emitting diodes (QD-LEDs), known for their high color quality and cost-effectiveness, have emerged as promising candidates for next-generation display and lighting technologies. However, suboptimal electron concentration resulting from defects at the QD core/shell interface limits the brightness and operational lifetime, thereby hindering the commercialization of QD-LEDs. Here, we present high-brightness and stable LEDs based on oleylamine (OAM)-assisted green ZnCdSe/ZnSeS/ZnS QDs. OAM treatment alleviates the dangling bonds on the QD core surfaces and eliminates defect states at the core/shell interface, thereby suppressing exciton quenching at the QD-electron transport layer (ETL) interface. Our findings demonstrate that QD-LEDs with OAM facilitate electron transport from the ETL to the QDs, increasing electron concentration, and reducing the hole injection barrier, ultimately accelerating carrier radiative recombination. Consequently, the green QD-LEDs exhibit a luminance of 1,105,500 cd/m² and a record-long T₉₅ operational lifetime of exceeding 24,800 h at 1000 cd/m². Our work provides an alternative pathway for the full-color and high-definition display application of high-performance QD-LEDs.

Quantum dot (QD) light-emitting diodes (QLEDs) have been considered one of the most promising candidates for next-generation lighting and displays. However, the suboptimal carrier dynamics at the interface between QDs and the hole transport layer (HTL), such as leakage and quenching induced by the accumulation of electrons at high brightness, severely deteriorates the device’s efficiency and stability. Here, we introduced the influence of carrier modulation by nanoshell engineering on the extermal quantum efficiency (EQE) and operation lifetime for QLEDs with large-sized QDs. The shell-driven engineering of energy level positions and band bending effectively eliminates the hole injection barrier and promotes charge injection balance. Photo-assisted Kelvin probe technique reveals that the ZnCdSe/ZnSeS QD/TFB (TFB = poly(9,9-dioctylfluorene-co-N-(4-(3-methylpropyl))diphenylamine)) interface presents an increased surface potential and quasi-Fermi level splitting, reducing heat generation during device operation at high brightness. The shell-driven carrier engineering strategy reveals that our devices exhibit a high external quantum efficiency of 26.44% and an ultralong operation time (exceeding 50,000 h) to 95% of the initial luminance at 1000 cd/m² (T₉₅@1000 cd/m²). We anticipate that our results provide insights into resolving the issues at the QD-HTL interface and demonstrate the importance of carrier management driven by QD nanostructure tailoring for the commercialization of QLEDs.