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

• Published in: Journal of luminescence 2021-12, Vol.240, p.118415, Article 118415
• Main Authors: Yoo, Jeong-Yeol, Choi, Yoon-Jeong, Kim, Jong-Gyu
• Format: Article
• Language: English
• Subjects: Blue emitting; Color purity; Gradient shell; QD-LED; ZnSeS Quantum dots
• ISSN: 0022-2313; 1872-7883
• DOI: 10.1016/j.jlumin.2021.118415

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). •High-quality blue ZnSeS QDs with a uniform alloy as an intermediate shell prepared.•These exhibited excellent crystallinity and fluorescent stability and possessed outstanding PL properties.•QY of 78% and FWHM of 12 nm at an emission of 445 nm.•Corresponding QLEDs exhibited a maximum brightness of 3,359 cd/m2, EQE of 3.5%, EL FWHM of 16 nm, and CIE of (0.157, 0.045).