Synthesis of Cu-Modified Nickel Oxide Nanocrystals and Their Applications as Hole-Injection layers for Quantum-Dot Light-Emitting Diodes |
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Authors: | Hui Du Luying Ma Dr. Xin Wang Yifei Li Maopeng Xu Dr. Xiaoyong Liang Dr. Desui Chen Prof. Yizheng Jin |
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Affiliation: | 1. Zhejiang Key Laboratory for Excited-State Materials, State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027 P. R. China;2. Zhejiang Key Laboratory for Excited-State Materials, State Key Laboratory of Silicon Materials, Department of Chemistry, Zhejiang University, Hangzhou, 310027 P. R. China |
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Abstract: | Solution-processed NiOx thin films have been applied as hole-injection layers (HILs) in quantum-dot light-emitting diodes (QLEDs). The commonly used NiOx HILs are prepared by the precursor-based route, which requires high annealing temperatures of over 275 °C to in situ convert the precursors into oxide films. Such high processing temperatures of NiOx HILs hinder their applications in flexible devices. Herein, we report a low-temperature approach based on Cu-modified NiOx (NiOx-Cu) nanocrystals to prepare HILs. A simple post-synthetic surface-modification step, which anchors the copper agents onto the surfaces of oxide nanocrystals, is developed to improve the electrical conductivity of the low-temperature-processed (135 °C) oxide-nanocrystal thin films. In consequence, QLEDs based on the NiOx-Cu HILs exhibit an external quantum efficiency of 17.5 % and a T95 operational lifetime of ∼2,800 h at an initial brightness of 1,000 cd m−2, meeting the commercialization requirements for display applications. The results shed light on the potential of using NiOx-Cu HILs for realizing high-performance flexible QLEDs. |
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Keywords: | Cu-modified nickel oxide nanocrystals hole-injection layers light-emitting diodes low-temperature-processed quantum dots |
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