Article abstract
Nature Photonics 1, 717 - 722 (2007)
Published online: 18 November 2007 | doi:10.1038/nphoton.2007.226
Subject Categories: Lasers, LEDs and light sources | Quantum optics
Bright, multicoloured light-emitting diodes based on quantum dots
Qingjiang Sun1, Y. Andrew Wang2, Lin Song Li2, Daoyuan Wang2, Ting Zhu3, Jian Xu3, Chunhe Yang1 & Yongfang Li1
Abstract
Quantum-dot-based LEDs are characterized by pure and saturated emission colours with narrow bandwidth, and their emission wavelength is easily tuned by changing the size of the quantum dots. However, the brightness, efficiency and lifetime of LEDs need to be improved to meet the requirements of commercialization in the near future. Here, we report red, orange, yellow and green LEDs with maximum luminance values of 9,064, 3,200, 4,470 and 3,700 cd m-2, respectively, the highest values reported so far. Solution-processable core–shell quantum dots with a CdSe core and a ZnS or CdS/ZnS shell were used as emissive layers in the devices. By optimizing the thicknesses of the constituent layers of the devices, we were able to develop quantum-dot-based LEDs with improved electroluminescent efficiency (1.1–2.8 cd A-1), low turn-on voltages (3–4 V) and long operation lifetimes. These findings suggest that such quantum-dot-based LEDs will be promising for use in flat-panel displays.
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, China
- Ocean NanoTech, 700 Research Center Boulevard, Fayetteville, Arkansas 72701, USA
- Department of Engineering Science and Mechanics, Penn State University, University Park, Pennsylvania 16802, USA
Correspondence to: Yongfang Li1 e-mail: liyf@iccas.ac.cn
Correspondence to: Y. Andrew Wang2 e-mail: awang@oceannanotech.com
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