Bright colloidal quantum dot light-emitting diodes enabled by efficient chlorination /639/925 /639/638/542 article

Xiyan Li, Yong Biao Zhao, Fengjia Fan*, Larissa Levina, Min Liu, Rafael Quintero-Bermudez, Xiwen Gong, Li Na Quan, James Fan, Zhenyu Yang, Sjoerd Hoogland, Oleksandr Voznyy, Zheng Hong Lu, Edward H. Sargent

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

292 Scopus citations

Abstract

The external quantum efficiencies of state-of-the-art colloidal quantum dot light-emitting diodes (QLEDs) are now approaching the limit set by the out-coupling efficiency. However, the brightness of these devices is constrained by the use of poorly conducting emitting layers, a consequence of the present-day reliance on long-chain organic capping ligands. Here, we report how conductive and passivating halides can be implemented in Zn chalcogenide-shelled colloidal quantum dots to enable high-brightness green QLEDs. We use a surface management reagent, thionyl chloride (SOCl2), to chlorinate the carboxylic group of oleic acid and graft the surfaces of the colloidal quantum dots with passivating chloride anions. This results in devices with an improved mobility that retain high external quantum efficiencies in the high-injection-current region and also feature a reduced turn-on voltage of 2.5 V. The treated QLEDs operate with a brightness of 460,000 cd m-2, significantly exceeding that of all previously reported solution-processed LEDs.

Original languageEnglish (US)
Pages (from-to)159-164
Number of pages6
JournalNature Photonics
Volume12
Issue number3
DOIs
StatePublished - Mar 1 2018

ASJC Scopus subject areas

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

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