1. Bright alloy type-II quantum dots and their application to light-emitting diodes.
- Author
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Jin, Xiao, Li, Haiyang, Huang, Shujuan, Gu, Xiaobing, Shen, Huaibin, Li, Danyang, Zhang, Xugu, Zhang, Qin, Li, Feng, and Li, Qinghua
- Subjects
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LIGHT emitting diodes , *QUANTUM dots , *LIGHT sources , *HETEROSTRUCTURES , *PHOTOLUMINESCENCE , *CHEMICAL yield - Abstract
Type-II quantum dots (QDs) are emerging as a promising candidate for full color light sources owing to their advantages in achieving full color light by tuning the heterostructures. Despite the recent developments in type-II QDs, the choices of proper materials are limited for the composition of a high-quality QD and it still remains a big challenge to enhance the photoluminescence (PL) quantum yields (QYs) of type-II QDs for light-emitting diode (LED) applications. Here, we develop Cd x Zn 1−x S/ZnSe/ZnS type-II QDs with a maximum quantum yield as high as 88.5%. Time-resolved PL results show that the ZnS shell suppresses non-radiative pathways by passivating the surface of Cd x Zn 1−x S/ZnSe, thus leading to a high QY. Moreover, our results demonstrate that the outer ZnS also benefits the charge injection and radiative recombinations of the Cd x Zn 1−x S/ZnSe. The LED based on green Cd 0.2 Zn 0.8 S/ZnSe/ZnS QDs achieves a current efficiency (CE) of 9.17 cd A −1 , an external quantum efficiency (EQE) of 8.78% and a low turn-on voltage of ∼2.3 V. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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