High Color Rendering Index Hybrid III-Nitride/Nanocrystals White Light-Emitting Diodes

• Published in: Advanced functional materials Vol. 26; no. 1; pp. 36 - 43
• Main Authors: Zhuang, Zhe, Guo, Xu, Liu, Bin, Hu, Fengrui, Li, Yi, Tao, Tao, Dai, Jiangping, Zhi, Ting, Xie, Zili, Chen, Peng, Chen, Dunjun, Ge, Haixiong, Wang, Xiaoyong, Xiao, Min, Shi, Yi, Zheng, Youdou, Zhang, Rong
• Format: Journal Article
• Language: English
• Published: Blackwell Publishing Ltd 06.01.2016
• Subjects: CdSe/ZnS nanocrystals; color rendering index; Color temperature; Emittance; Hybrid structures; Indium gallium nitrides; InGaN/GaN nanoholes; Light-emitting diodes; Nanocrystals; nanoimprint lithography; Nanostructure; nonradiative energy transfer; Rendering
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.201502870

An excellent hybrid III‐nitride/nanocrystal nanohole light‐emitting diode (h‐LED) has been developed utilizing nonradiative resonant energy transfer (NRET) between violet/blue emitting InGaN/GaN multiple quantum wells (MQWs) and various wavelength emitting nanocrystals (NCs) as color‐conversion mediums. InGaN/GaN MQWs are fabricated into nanoholes by soft nanoimprint lithography to minimize the separation between MQWs and NCs. A significant reduction in the decay lifetime of excitons in the MQWs of the hybrid structure has been observed as a result of the NRET from the nitride emitter to NCs. The NRET efficiency of the hybrid structures is obtained from the decay curves, as high as 80%. Moreover, a modified Förster formulation has exhibited that the exciton coupling distance in the hybrid structures is less than the Förster's radius, demonstrating a strong coupling between MQWs and NCs. Finally, based on a systemic optimization for white emission indexes, a series of hybrid ternary complementary color h‐LEDs have been demonstrated with a high color rendering index, up to 82, covering the white light emission at different correlated color temperatures ranging from 2629 to 6636 K, corresponding to warm white, natural white, and cold white. White light‐emitting diodes, with a novel nanohole nitride quantum well/II–VI nanocrystal hybrid structure, are demonstrated. High color‐conversion efficiency and high effective quantum yield are achieved in these devices by utilizing an efficient nonradiative energy transfer. Moreover, they can realize a high color rendering index, covering different correlated color temperatures corresponding to warm white, natural white, and cold white.