Ligand-Asymmetric Janus Quantum Dots for Efficient Blue-Quantum Dot Light-Emitting Diodes

Ikjun Cho, Heeyoung Jung, Byeong Guk Jeong, Donghyo Hahm, Jun Hyuk Chang, Taesoo Lee, Kookheon Char, Doh C. Lee, Jaehoon Lim, Changhee Lee, Jinhan Cho, Wan Ki Bae

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

We present ligand-asymmetric Janus quantum dots (QDs) to improve the device performance of quantum dot light-emitting diodes (QLEDs). Specifically, we devise blue QLEDs incorporating blue QDs with asymmetrically modified ligands, in which the bottom ligand of QDs in contact with ZnO electron-transport layer serves as a robust adhesive layer and an effective electron-blocking layer and the top ligand ensures uniform deposition of organic hole transport layers with enhanced hole injection properties. Suppressed electron overflow by the bottom ligand and stimulated hole injection enabled by the top ligand contribute synergistically to boost the balance of charge injection in blue QDs and therefore the device performance of blue QLEDs. As an ultimate achievement, the blue QLED adopting ligand-asymmetric QDs displays 2-fold enhancement in peak external quantum efficiency (EQE = 3.23%) compared to the case of QDs with native ligands (oleic acid) (peak EQE = 1.49%). The present study demonstrates an integrated strategy to control over the charge injection properties into QDs via ligand engineering that enables enhancement of the device performance of blue QLEDs and thus promises successful realization of white light-emitting devices using QDs.

Original languageEnglish
Pages (from-to)22453-22459
Number of pages7
JournalACS Applied Materials and Interfaces
Volume10
Issue number26
DOIs
Publication statusPublished - 2018 Jul 5

Keywords

  • charge balance
  • hole transport layer engineering
  • interface engineering
  • ligand-asymmetric quantum dot
  • quantum dot-based light-emitting diode

ASJC Scopus subject areas

  • Materials Science(all)

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    Cho, I., Jung, H., Jeong, B. G., Hahm, D., Chang, J. H., Lee, T., Char, K., Lee, D. C., Lim, J., Lee, C., Cho, J., & Bae, W. K. (2018). Ligand-Asymmetric Janus Quantum Dots for Efficient Blue-Quantum Dot Light-Emitting Diodes. ACS Applied Materials and Interfaces, 10(26), 22453-22459. https://doi.org/10.1021/acsami.8b08300