Carbazole-based coplanar molecule (CmInF) as a universal host for multi-color electrophosphorescent devices

Cheuk Lam Ho, Liang Chen Chi, Wen Yi Hung, Wei Jiun Chen, Yu Cheng Lin, Hao Wu, Ejabul Mondal, Gui Jiang Zhou, Ken Tsung Wong, Wai Yeung Wong

Research output: Journal article publicationJournal articleAcademic researchpeer-review

107 Citations (Scopus)

Abstract

The synthesis, isomerism, photophysics and electrophosphorescent characterization of some functional cyclometallated iridium(iii) complexes containing 2-[2-(N-phenylcarbazolyl)]pyridine and 2-[3-(N-phenylcarbazolyl)] pyridine molecular frameworks are described. A carbazole-based coplanar molecule (CmInF) obtained through the intramolecular ring closure of aryl substitutions at the C3 and C6 positions exhibits a high triplet energy (ET= 2.77 eV), morphological stability (Tg= 195 °C) and hole mobility in the range of up to 5 × 10-3cm2V-1s-1. Highly efficient multi-color electrophosphorescent devices have been successfully achieved employing CmInF as the universal host material doped with phosphorescent dopants of various colors under the same device configuration of ITO/PEDOT:PSS (300 Å)/TCTA (250 Å)/CmInF: dopant (250 Å)/TAZ (500 Å)/LiF/Al (PEDOT:PSS = poly(ethylene dioxythiophene):polystyrene sulfonate; TCTA = 4,4′,4′′-tri(N- carbazolyl)triphenylamine; TAZ = 3-(4-biphenylyl)-4-phenyl-5-(4-tert- butylphenyl)-1,2,4-triazole). Through the mixing of two phosphorescent dopants of complementary colors, we also fabricated a two-color white organic light-emitting device (WOLED) with the same device structure consisting of 12 wt% FIrpic and 0.3 wt% (Mpg)2Ir(acac) co-doped into CmInF as a single-emitting-layer, which exhibits peak WOLED efficiency of 13.4% (23.4 cd A-1) and 11.2 lm W-1with the Commission Internationale de L'Eclairage (CIE) coordinates of (0.33, 0.37). In addition, the use of such device structure in full-color OLEDs has the advantages of simplifying manufacturing process and reducing production cost that are the critical issues of commercialization.
Original languageEnglish
Pages (from-to)215-224
Number of pages10
JournalJournal of Materials Chemistry
Volume22
Issue number1
DOIs
Publication statusPublished - 7 Jan 2012
Externally publishedYes

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Chemistry

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