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

Yangyang Bian; Xiaohan Yan; Fei Chen; Qian Li; Bo Li; Wenjun Hou; Zizhe Lu; Shuaibing Wang; Han Zhang; Wenjing Zhang; Dandan Zhang; Aiwei Tang; Fengjia Fan; Huaibin Shen

doi:10.1038/s41586-024-08197-z

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

Nature. 2024 Nov 20. doi: 10.1038/s41586-024-08197-z. Online ahead of print.

Authors

Yangyang Bian^#^{1

2

3}, Xiaohan Yan^#², Fei Chen⁴, Qian Li¹, Bo Li², Wenjun Hou⁵, Zizhe Lu⁵, Shuaibing Wang³, Han Zhang¹, Wenjing Zhang¹, Dandan Zhang¹, Aiwei Tang⁶, Fengjia Fan⁷, Huaibin Shen⁸

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.
² CAS Key Laboratory of Microscale Magnetic Resonance, School of Physical Sciences, Hefei National Laboratory, and Anhui Province Key Laboratory of Scientific Instrument Development and Application, University of Science and Technology of China, Hefei, China.
³ Key Laboratory of Luminescence and Optical Information, Ministry of Education, School of Physical Science and Engineering, Beijing Jiaotong University, Beijing, China.
⁴ 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. chenfei.henu@henu.edu.cn.
⁵ TCL Corporate Research, Shenzhen, China.
⁶ Key Laboratory of Luminescence and Optical Information, Ministry of Education, School of Physical Science and Engineering, Beijing Jiaotong University, Beijing, China. awtang@bjtu.edu.cn.
⁷ CAS Key Laboratory of Microscale Magnetic Resonance, School of Physical Sciences, Hefei National Laboratory, and Anhui Province Key Laboratory of Scientific Instrument Development and Application, University of Science and Technology of China, Hefei, China. ffj@ustc.edu.cn.
⁸ 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. shenhuaibin@henu.edu.cn.

^# Contributed equally.

PMID: 39567695
DOI: 10.1038/s41586-024-08197-z

Abstract

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 lighting^1-3. 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, respectively^3,4.