Luminous efficiency enhancement in blue phosphorescent organic light-emitting diodes with an electron confinement layers

Jin Sung Kang, Ju An Yoon, Seung Il Yoo, Jin Wook Kim, Seungjun Yi*, Fu Rong ZHU, Kok Wai CHEAH, Woo Young Kim

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)

Abstract

This study reports the results of blue phosphorescent organic light emitting diodes (PHOLEDs) employing an electron confinement layer (ECL), tris-(phenylpyrazole)iridium (Ir(ppz)3) and a hole confinement layer (HCl), 1,3,5-tris(N-phenylbenzimiazole-2-yl)benzene (TPBi). The electrical and optical characteristics of PHOLEDs with different emissive layers, including current density, luminance, and luminous efficiency, were analyzed. The thickness of the individual emissive layer was optimized, however, and the total thickness of the emitting region was kept constant at 300 Å. This work reveals that the effective electron confinement, due to a large energy level offset between the electron confinement and emitting layers, helps to improve hole-electron current balance in the emitting region. The maximum external quantum efficiency of 23.40% at 1500 cd/m2 was achieved for PHOLEDs with an ECL, which is 60% higher than the structural identical control device without ECL.

Original languageEnglish
Pages (from-to)78-82
Number of pages5
JournalOptical Materials
Volume47
DOIs
Publication statusPublished - 2015

Scopus Subject Areas

  • Electronic, Optical and Magnetic Materials
  • Computer Science(all)
  • Atomic and Molecular Physics, and Optics
  • Spectroscopy
  • Physical and Theoretical Chemistry
  • Organic Chemistry
  • Inorganic Chemistry
  • Electrical and Electronic Engineering

User-Defined Keywords

  • Blue phosphorescent OLED
  • Electron confinement layer (ECL)
  • External quantum efficiency
  • Hole confinement layer (HCL)
  • Luminous efficiency

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