Alloyed Green-Emitting CdZnSeS/ZnS Quantum Dots with Dense Protective Layers for Stable Lighting and Display
Hongcheng Yang1,2, Yizun Liu3, Junjie Hao1,3,2
1Guangdong University Key Laboratory for Advanced Quantum Dot Displays and Lighting, Guangdong-Hong Kong-Macao Joint Laboratory for Photonic-Thermal-Electrical Energy Materials and Devices, and Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen 518055, China.
Abstract:
Alloyed green-emitting CdZnSeS/ZnS quantum dots (QDs) demonstrate potential applications in solid-state lighting and displays owing to their various advantages, such as high color purity, light conversion efficiency, and color rendering index. However, their applications in white light-emitting diodes (WLEDs) are limited by their poor photostabilities on blue-emitting gallium nitride (GaN) LED chips. In this study, the effect of the specific surface area (SSA) in the coating layers on the photostabilities of QDs was investigated. SSA was adjusted by controlling the proportions of dense aluminum oxide (AlO) layers and porous silica dioxide (SiO2) layers to fabricate QD protective layers via a catalyst-free sol-gel method. The results showed that the synthesized AlO possessing the lowest SSA among the synthesis protective layers presented the best QD photostabilities on the LED chips. Moreover, they exhibited a 9.9-fold increase in the operational lifetime (T80) compared to that of pristine QDs. In addition, the QD-based WLED achieved an excellent display performance with a wide color gamut (115%) of the National Television System Committee (NTSC) color gamut standard. This approach offers a promising strategy for enhancing the QD photostabilities for applications in solid-state lighting and displays by coating the protective layers on the QD surface.
