Controlling charge balance using non-conjugated polymer interlayer in quantum dot light-emitting diodes

Jinyoung Yun, Jaeyun Kim, Ho Kyun Jang, Kook Jin Lee, Jung Hwa Seo, Byung Jun Jung, Gyutae Kim, Jeonghun Kwak

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

The balance of electron–hole charge carriers in quantum dot (QD) light-emitting diodes (QLEDs) is an important factor to achieve high efficiency. However, poor interfacial properties between QDs and their adjacent layers are likely to deteriorate the electron–hole charge balance, resulting in the poor performance of a QLED. In this paper, we report an enhanced efficiency in red-emitting inverted QLEDs by modifying the interface properties between QDs and ZnO electron transport layer (ETL) using a thin layer of non-conjugated polymer, poly(4-vinylpyridine) (PVPy). Based on the precise control of the electrical properties with PVPy, the maximum efficiency of the QLED is enhanced by 30% compared to the device without a PVPy layer. In particular, the efficiency at low current density region is significantly increased. We investigate the effect of the PVPy interlayer on the performance of QLEDs and find that this thin layer not only shifts the energy levels of the underlying ZnO ETL, but also effectively blocks the leakage current at the ETL/QD interface.

Original languageEnglish
Pages (from-to)82-86
Number of pages5
JournalOrganic Electronics
Volume50
DOIs
Publication statusPublished - 2017 Nov

Keywords

  • Interlayer
  • Light-emitting diodes
  • QLEDs
  • Quantum dots
  • poly(4-vinylpyridine) (PVPy)

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Chemistry(all)
  • Condensed Matter Physics
  • Materials Chemistry
  • Electrical and Electronic Engineering

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