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The Zn1−xMgxO electron transport layer for charge balance in high-brightness inverted quantum-dot light-emitting diodes

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Abstract

Colloidal quantum-dot light-emitting diodes (QLEDs) are rapidly gaining recognition as formidable contenders in the realm of next-generation lighting and display devices. Notwithstanding, the journey to commercialization of QLED devices encounters a roadblock in the form of inadequate flexibility exhibited by the electron transport layer, which is typically made of ZnO nanoparticles. The hindrance stems from the substantial specific surface area, existence of surface defect states, and the fixed ZnO bandgap. To surmount these obstacles, we delved into the potential of integrating Mg element as a dopant in ZnO, aiming to enhance the surface chemistry, electrical characteristics, and film morphology of colloidal ZnO nanoparticles. The results clearly indicated that Mg doping played a critical role in diminishing surface defects in ZnO, while simultaneously reducing the density of oxygen vacancies, thereby regulating its electron mobility. Through modulation of the Mg doping concentration, the bandgap width of ZnO can be fine-tuned, leading to the creation of a more suitable electron transport layer. The inverted QLED devices based on Zn1−xMgxO electron transport layers exhibited remarkable advancements, with a peak external quantum efficiency and current efficiency of 6.7% and 29 cd A−1, respectively. These values surpassed those of reference devices by 35 and 28%, underscoring the efficacy of Zn1−xMgxO as a viable approach for enhancing the efficiency of QLED devices.

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Data availability

Authors state that data supporting the results of our work are present within this research paper. The raw data collected during experiments are obtainable from the corresponding author, if required, on reasonable request.

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Funding

This research was funded by the National Natural Science Foundation of China, Grant No.  52202168, the Excellent Youth Fund of Henan Natural Science Foundation, China, Grant No. 212300410031, Key Technologies R&D Program of Henan, Grant No. 232102210168 and 242102211083, the Scientific Research Foundation of the Higher Education Institutions of Henan Province, China, Grant No. 23A140019 and 22B430009, and the Henan University of Engineering Foundation, China, Grant No. DKJ2019012.

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Authors and Affiliations

  1. College of Materials Engineering, Henan University of Engineering, Zhengzhou, China

    Ling Chen, Yukai Zhang, Yunling Kun, Kun Tuo, Jifang Shang, Wenjing Du & Shaohui Liu

  2. College of Science, Zhongyuan University of Technology, Zhengzhou, China

    Hui Qi

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  1. Ling Chen
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Chen, L., Zhang, Y., Kun, Y. et al. The Zn1−xMgxO electron transport layer for charge balance in high-brightness inverted quantum-dot light-emitting diodes. J Mater Sci: Mater Electron 35, 754 (2024). https://doi.org/10.1007/s10854-024-12556-x

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