Silicon-Quantum-Dot Light-Emitting Diodes With Interlayer-Enhanced Hole Transport

Silicon-Quantum-Dot Light-Emitting Diodes With Interlayer-Enhanced Hole Transport

Despite the technological importance of silicon quantum dots (Si QDs) which are solely made of abundant and nontoxic Si, Si-QD light-emitting diodes (LEDs) clearly lag behind those based on other QDs, especially Cd- or Pb-containing QDs. It is imperative that novel measures should be taken to boost...

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Bibliographic Details
Main Authors: Wei Gu, Xiangkai Liu, Xiaodong Pi, Xingliang Dai, Shuangyi Zhao, Li Yao, Dongsheng Li, Yizheng Jin, Mingsheng Xu, Deren Yang, Guogang Qin
Format: Article
Language:English
Published: IEEE 2017-01-01
Series:IEEE Photonics Journal
Subjects:
Silicon quantum dots (Si QDs)
light-emitting diodes (LEDs)
interlayer
hole transport
Online Access:https://ieeexplore.ieee.org/document/7858634/
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Summary:Despite the technological importance of silicon quantum dots (Si QDs) which are solely made of abundant and nontoxic Si, Si-QD light-emitting diodes (LEDs) clearly lag behind those based on other QDs, especially Cd- or Pb-containing QDs. It is imperative that novel measures should be taken to boost the performance of Si-QD LEDs. Here, we demonstrate that Si-QD LEDs can work much more efficiently after the use of interlayers between indium tin oxide (ITO) and poly(ethylene-dioxythiophene):polystyrene sulphonate (PEDOT:PSS) to enhance the hole transport of the devices. The interlayer of dipyrazino (2, 3-f:2&#x00A0;&#x2032;, 3&#x00A0;&#x2032;-h) quinoxaline-2,3,6,7,10,11-hexacarbonitrile (HAT-CN) or MoO<sub>3</sub> increases the work function of ITO and improves the band alignment, leading to better hole injection from ITO to PEDOT:PSS. The resulting mitigated charge unbalance causes both the external quantum efficiency (EQE) and stability of Si-QD LEDs to significantly increase (up to &#x223C;170&#x0025; for EQE and &#x223C;240&#x0025; for device half-lifetime). The highest EQE of &#x223C;2.4&#x0025; obtained in the current work is among the best values that have been reported for Si-QD LEDs. Even without encapsulation, the device half-lifetime is up to &#x223C;8.5 h. The enhancement of the hole transport induced by MoO<sub>3</sub> is more significant than that induced by HAT-CN. Therefore, MoO<sub>3</sub> more significantly enhances the performance of Si-QD LEDs than HAT-CN.
ISSN:1943-0655

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