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Minimizing heat generation in quantum dot light-emitting diodes by increasing quasi-Fermi-level splitting

Nature Nanotechnology volume 18, pages 1168–1174 (2023)Cite this article

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Abstract

Minimizing heat accumulation is essential to prolonging the operational lifetime of quantum dot light-emitting diodes (QD-LEDs). Reducing heat generation at the source is the ideal solution, which requires high brightness and quantum efficiency at low driving voltages. Here we propose to enhance the brightness of QD-LEDs at low driving voltages by using a monolayer of large QDs to reduce the packing number in the emitting layer. This strategy allows us to achieve a higher charge population per QD for a given number of charges without charge leakage, enabling enhanced quasi-Fermi-level splitting and brightness at low driving voltage. Due to the minimized heat generation, these LEDs show a high power conversion efficiency of 23% and a T95 operation lifetime (the time for the luminance to decrease to 95% of the initial value) of more than 48,000 h at 1,000 cd m−2.

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Fig. 1: Mitigating heat generation in QD-LEDs by achieving high brightness at low driving voltages.
Fig. 2: Characterizations of QD-LEDs.
Fig. 3: Electron quasi-Fermi-level splitting measurements.
Fig. 4: Device temperature at different brightnesses.
Fig. 5: Device stability tests.

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Data availability

The data that support the findings of this study are available from the corresponding author upon reasonable request. They are also available at figshare: https://doi.org/10.6084/m9.figshare.22817639, or from the attached Source Data files. Source data are provided with this paper.

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Acknowledgements

We gratefully acknowledge financial support from the National Natural Science Foundation of China (grant numbers U22A2072, 52272167, 62234006, 81788101, 11761131011, 51872275), the National Key R&D Program of China (grant number 2018YFA0306600), and the Postgraduate Cultivating Innovation and Quality Improvement Action Plan of Henan University (grant number SYLYC2022127).

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Author notes

  1. These authors contributed equally: Yan Gao, Bo Li, Xiaonan Liu.

Authors and Affiliations

  1. Key Laboratory for Special Functional Materials of Ministry of Education, National & Local Joint Engineering Research Center for High-efficiency Display and Lighting Technology, Henan University, Kaifeng, China

    Yan Gao, Xiaonan Liu, Huaibin Shen, Jiaojiao Song, Yihua Chong, Ruyun Yao, Shujie Wang, Lin Song Li & Zuliang Du

  2. Hefei National Laboratory for Physical Sciences at the Microscale and Department of Modern Physics, CAS Key Laboratory of Microscale Magnetic Resonance, Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, China

    Bo Li, Yang Song, Zhijie Yan, Xiaohan Yan & Fengjia Fan

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  1. Yan Gao
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Contributions

H.S. and F.F. conceived the concept and designed the experiments. H.S., F.F. and Z.D. supervised the project. Y.G., X.L. and J.S. synthesized the materials, fabricated the devices and collected the performance data of the QD-LEDs. B.L. and Y.S. developed the thermal simulation model and the electrical pump optical probe spectroscopy. F.F., H.S. and B.L. wrote the manuscript. All authors contributed to the scientific discussion and editing the manuscript.

Corresponding authors

Correspondence to Huaibin Shen, Fengjia Fan or Zuliang Du.

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The authors declare no competing interests.

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Nature Nanotechnology thanks Yanping Wang and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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Supplementary text, Figs. 1–17 and Tables 1–6.

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Gao, Y., Li, B., Liu, X. et al. Minimizing heat generation in quantum dot light-emitting diodes by increasing quasi-Fermi-level splitting. Nat. Nanotechnol. 18, 1168–1174 (2023). https://doi.org/10.1038/s41565-023-01441-z

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