ZnSe:Te/ZnSeS/ZnS nanocrystals: an access to cadmium-free pure-blue quantum-dot light-emitting diodes. Issue 21 (20th May 2020)

• Record Type: Journal Article
• Authors: Bao, Zhen; Jiang, Zhen-Feng; Su, Qiang; Chiu, Hsin-Di; Yang, Heesun; Chen, Shuming; Chung, Ren-Jei; Liu, Ru-Shi
• Is Part Of: Nanoscale. Volume 12:Issue 21(2020)
• Page Start: 11556
• Page End: 11561
• Publication Date: 2020-05-20
• Subjects: Nanoscience -- Periodicals; Nanotechnology -- Periodicals; 620.505
• DOI: 10.1039/d0nr01019g
• Languages: English
• ISSNs: 2040-3364

Abstract

Abstract : The emission wavelength of ZnSe/ZnS quantum dots was successfully tuned from the violet (∼420 nm) to pure-blue (∼455 nm) region by doping Te into the ZnSe core. A specific structure QLED fabricated with ZnSe:0.03Te/ZnSeS/ZnS QDs realized pure-blue emission. Abstract : Cadmium-free quantum dots (QDs) are attracting considerable research attention because of their low toxicity. However, the bandgap of most cadmium-free QDs avoids the pure-blue region, which leads to difficulty in realizing pure-blue quantum-dot light-emitting diodes (QLEDs). In this work, we successfully tuned the emission wavelength of ZnSe/ZnS quantum dots from the violet region (∼420 nm) to the pure-blue region (450–460 nm) by doping Te into the ZnSe core. The ZnSe:0.03Te/ZnSeS/ZnS QD sample with emission at 450 nm and a quantum yield of 30% was the most balanced formula. To overcome the energy gap between the hole-transfer layer and QD layers, a specific hole-transfer layer was developed for normal-structure QLEDs. A QLED with such a structure with ZnSe:0.03Te/ZnSeS/ZnS QDs achieved the pure-blue light emission at 455 nm, a low turn-on voltage of 4.4 V, and an external quantum efficiency of 0.33%. Overall, our cadmium-free QLED achieved pure-blue emission, revealing the potential of ZnSe-based pure-blue QLEDs for future displays.