Synthesis of narrow blue emission gradient ZnSeS quantum dots and their quantum dot light-emitting diode device performance

The performance of blue quantum dot light-emitting diode (QD-LED) device as one of the three primary color sources still lag behind that of red and green QD-LEDs. In this study, to obtain highly brightness, excellent color purity, and environmentally friendly blue-light-emitting materials for next generation display applications, we designed and synthesized ZnSeS quantum dots (GCS-QDs) from core Se–S composition-gradient to shell, in which the majority of Se resides close to the core domain and S dominantly locates outmost of the shells. The final GCS-QDs had a high quantum yield value of 78%, significantly narrow spectrum width of 12 nm, and reached an emission peak at 445 nm. Moreover, the blue-emitting QD-LED were fabricated by employing the GCS-QDs as light emitter, and the resulting device exhibited maximum brightness of 3,359 cd/m2, maximum current efficiency of 1.2 cd/A, maximum external efficiency of 3.5%, and full width at half maximum of only 16 nm at 448 nm).