Molecules (Sep 2014)

Novel Hole Transporting Materials Based on 4-(9H-Carbazol-9-yl)triphenylamine Derivatives for OLEDs

  • Quynh Pham Bao Nguyen,
  • Sueng Ji Baek,
  • Mi Jin Kim,
  • Na Young Shin,
  • Gyeong Woo Kim,
  • Dong Cheol Choe,
  • Jang Hyuk Kwon,
  • Kyu Yun Chai

DOI
https://doi.org/10.3390/molecules190914247
Journal volume & issue
Vol. 19, no. 9
pp. 14247 – 14256

Abstract

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During the past few years, organic light emitting diodes (OLEDs) have been increasingly studied due to their emerging applicability. However, some of the properties of existing OLEDs could be improved, such as their overall efficiency and durability; these aspects have been addressed in the current study. A series of novel hole-transporting materials (HTMs) 3a–c based on 4-(9H-carbazol-9-yl)triphenylamine conjugated with different carbazole or triphenylamine derivatives have been readily synthesized by Suzuki coupling reactions. The resulting compounds showed good thermal stabilities with high glass transition temperatures between 148 and 165 °C. The introduction of HTMs 3b and 3c into the standard devices ITO/HATCN/NPB/HTMs 3 (indium tin oxide/dipyrazino(2,3-f:2ꞌ,3ꞌ-h)quinoxaline 2,3,6,7,10,11-hexacarbonitrile/N,Nꞌ-bis(naphthalen-1-yl)-N,Nꞌ-bis(phenyl)-benzidine/HTMs)/CBP (4,4ꞌ-Bis(N-carbazolyl)-1,1ꞌ-biphenyl): 5% Ir(ppy)3/Bphen/LiF/Al (tris[2-phenylpyridinato-C2,N]iridium(III)/4,7-diphenyl-1,10-phenanthroline/LiF/Al) resulted in significantly enhanced current, power, and external quantum efficiencies (EQE) as compared to the reference device without any layers of HTMs 3.

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