Dipole–dipole-interaction-assisted self-assembly of quantum dots for highly efficient light-emitting diodes

Huaiyu Xu, Jiaojiao Song, Penghao Zhou, Yang Song, Jian Xu, Huaibin Shen*, Shucheng Fang, Yan Gao, Zhenjiang Zuo, João M. Pina, Oleksandr Voznyy, Chunming Yang, Yongfeng Hu, Jun Li, Jiangfeng Du*, Edward H. Sargent*, Fengjia Fan*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

The external quantum efficiency of state-of-the-art quantum dot light-emitting diodes is limited by the low photon out-coupling efficiency. Light-emitting diodes using oriented nanostructures such as nanorods, nanoplatelets and dot-in-disc nanocrystals favour photon out-coupling; however, their internal quantum efficiency is often compromised and thus achieving a net gain has proved challenging. Here we report isotropic-shaped quantum dots featuring a mixed-crystallographic structure composed of wurtzite and zinc blende phases. The wurtzite phase promotes dipole–dipole interactions that orient quantum dots in solution-processed films, whereas the zinc blende phase helps lift the electronic state degeneracy to enable directional light emission. These combined features improve photon out-coupling without compromising internal quantum efficiency. Fabricated light-emitting diodes exhibit an external quantum efficiency of 35.6% and can be continuously operated with an initial brightness of 1,000 cd m2 for 4.5 years with a minimal performance loss of about 5%.

Original languageEnglish (US)
Pages (from-to)186-191
Number of pages6
JournalNature Photonics
Volume18
Issue number2
DOIs
StatePublished - Feb 2024

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics

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