Bright and stable green quantum dot light-emitting diodes via increasing electron concentration

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.