Color tuning of iridium complexes for organic light-emitting diodes: The electronegative effect and π-conjugation effect

Cheng Hsien Yang, Kai Hung Fang, Wei Lin Su, Shao Pin Wang, Shih Kang Su, I. Wen Sun

Research output: Contribution to journalArticlepeer-review

24 Citations (Scopus)

Abstract

Novel red phosphorescent emitter bis(4-phenylquinazolinato-N,C2′) iridium(acetylacetonate) [(pqz)2Ir(acac)], bis(1-(1′-naphthyl)-5-methylisoquinolinato-N,C2′)iridium(acetylacetonate) [(1-mniq)2Ir(acac)] and bis(1-(2′-naphthyl)-5-methylisoquinolinato-N,C2′)iridium(acetylacetonate) [(2-mniq)2Ir(acac)] have been synthesized and fully characterized. The electronegative effect of (pqz)2Ir(acac) ligand shows almost the same influence as the extended π-conjugation effect of (2-mniq)2Ir(acac). Density functional theory (DFT) was applied to calculate the Kohn-Sham orbitals of HOMOs and LUMOs in the iridium complexes to illustrate the N(1) electronegative atom effect. Finally, lowest triplet state (T1) energies calculated by time-dependent DFT (TDDFT) were compared with the experimental electroluminescent data. The calculated data for the iridium complexes agreed fairly well with experimental data. Electroluminescent devices with a configuration of ITO/NPB/CBP:dopant/BCP/AlQ3/LiF/Al were fabricated. The device using (pqz)2Ir(acac) as a dopant showed deep-red emission with 1931 CIE (Commission International de L'Eclairage) chromaticity coordinates x = 0.70, y = 0.30.

Original languageEnglish
Pages (from-to)2767-2773
Number of pages7
JournalJournal of Organometallic Chemistry
Volume691
Issue number12
DOIs
Publication statusPublished - 2006 Jun 1

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Physical and Theoretical Chemistry
  • Organic Chemistry
  • Inorganic Chemistry
  • Materials Chemistry

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