Manipulating charge-transfer character with electron-withdrawing main-group moieties for the color tuning of iridium electrophosphors

Guijiang Zhou, Cheuk Lam Ho, Wai Yeung Wong, Qi Wang, Dongge Ma, Lixiang Wang, Zhenyang Lin, Todd B. Marder, Andrew Beeby

Research output: Journal article publicationJournal articleAcademic researchpeer-review

446 Citations (Scopus)

Abstract

A new and synthetically versatile strategy has been developed for the phosphorescence color tuning of cyclometalated iridium phosphors by simple tailoring of the phenyl ring of ppy (Hppy = 2-phenylpyridine) with various main-group moieties in [Ir(ppy-X)2(acac)] (X = B(Mes)2, SiPh3, GePh3, NPh2, POPh2, OPh, SPh, SO2Ph). This can be achieved by shifting the charge-transfer character from the pyridyl groups in some traditional iridium ppy-type complexes to the electron-withdrawing main-group moieties and these assignments were supported by theoretical calculations. This new color tuning strategy in IrIII-based triplet emitters using electron-withdrawing main-group moieties provides access to IrIIIphosphors with improved electron injection/electron transporting features essential for highly efficient, color-switchable organic light-emitting diodes (OLEDs). The present work furnished OLED colors spanning from bluish-green to red (505-609 nm) with high electroluminescence efficiencies which have great potential for application in multicolor displays. The maximum external quantum efficiency of 9.4%, luminance efficiency of 10.3 cd A-1and power efficiency of 5.0 Im W-1for the red OLED (X = B(Mes)2), 11.1 %, 35.0 cd A-1, and 26.8 Im W-1for the bluish-green device (X = OPh), 10.3%, 36.9 cd A-1, and 28.6 Im W-1for the bright green device (X = NPh2) as well as 10.7%, 35.1 cd A-1, and 23.1 Im W-1for the yellow-emitting device (X = SO2Ph) can be obtained. KGaA.
Original languageEnglish
Pages (from-to)499-511
Number of pages13
JournalAdvanced Functional Materials
Volume18
Issue number3
DOIs
Publication statusPublished - 11 Feb 2008
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Condensed Matter Physics
  • Electrochemistry

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