Efficient green InP-based QD-LED by controlling electron injection and leakage

• 成果类型: Article
• 署名作者: Bian, Yangyang; Yan, Xiaohan; Chen, Fei; Li, Qian; Li, Bo; Hou, Wenjun; Lu, Zizhe; Wang, Shuaibing; Zhang, Han; Zhang, Wenjing; Zhang, Dandan; Tang, Aiwei; Fan, Fengjia; Shen, Huaibin
• 署名单位: Henan University; Chinese Academy of Sciences; University of Science & Technology of China, CAS; Hefei National Laboratory; Chinese Academy of Sciences; University of Science & Technology of China, CAS; Beijing Jiaotong University; TCL Inc.
• 刊物名称: Nature
• ISSN/ISSBN: 0028-5414
• DOI: 10.1038/s41586-024-08197-z
• 发表日期: 2024-11-28
• 关键词: light-emitting-diodes; electroluminescence; nanocrystals; transport; DYNAMICS

摘要

Green indium phosphide (InP)-based quantum dot light-emitting diodes (QD-LEDs) still suffer from low efficiency and short operational lifetime, posing a critical challenge to fully cadmium-free QD-LED displays and lighting1-3. Unfortunately, the factors that underlie these limitations remain unclear and, therefore, no clear device-engineering guidelines are available. Here, by using electrically excited transient absorption spectroscopy, we find that the low efficiency of state-of-the-art green cadmium-free QD-LEDs (which ubiquitously adopt the InP-ZnSeS-ZnS core-shell-shell structure) originates from the ZnSeS interlayer because it imposes a high injection barrier that limits the electron concentration and trap saturation. We demonstrate, both experimentally and theoretically, that replacing the currently widely used ZnSeS interlayer with a thickened ZnSe interlayer enables improved electron injection and depressed leakage simultaneously, allowing to achieve a peak external quantum efficiency of 26.68% and T95 lifetime (time for the luminance to drop to 95% of the initial value) of 1,241 h at an initial brightness of 1,000 cd m-2 in green InP-based QD-LEDs emitting at 543 nm-exceeding the previous best values by a factor of 1.6 and 165, respectively3,4. Replacing ZnSeS with a thickened ZnSe layer in green InP-based QD-LEDs improves the efficiency and lifetime, boosting electron injection and reducing leakage, enabling 26.68% external quantum efficiency and 1,241 h T95 lifetime.