Robust tris-cyclometalated iridium(III) phosphors with ligands for effective charge carrier injection/transport: Synthesis, redox, photophysical, and electrophosphorescent behavior

Guijiang Zhou, Qi Wang, Cheuk Lam HO, Wai Yeung WONG*, Dongge Ma, Lixiang Wang, Zhenyang Lin

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

92 Citations (Scopus)

Abstract

With the target to design and develop new functionalized green triplet light emitters that possess distinctive electronic properties for robust and highly efficient phosphorescent organic light-emitting diodes (PHOLEDs), a series of bluish-green to yellow-green phosphorescent tris-cyclometalated homoleptic iridium(III) complexes [Ir(ppy-X)3] (X = SiPh3, GePh3, NPh2, POPh2, OPh, SPh, SO 2Ph, Hppy = 2-phenylpyridine) have been synthesized and fully characterized by spectroscopic, redox, and photophysical methods. By chemically manipulating the lowest triplet-state character of Ir(ppy)3 with some functional main-group 14-16 moieties on the phenyl ring of ppy, a new family of metallophosphors with high-emission quantum yields, short triplet-state lifetimes, and good hole-injection/holetransporting or electron-injection/ electron-transporting properties can be obtained. Remarkably, all of these IrIII complexes show outstanding electrophosphorescent performance in multilayer doped devices that surpass that of the state-of-the-art green-emitting dopant Ir(ppy)3. The devices described herein can reach the maximum external quantum efficiency (ηext) of 12.3%, luminance efficiency (ηL) of 50.8 cdA-1, power efficiency (ηp) of 36.9 LmW-1 for [Ir(ppy-SiPh 3)3], 13.9%, 60.8 cdA-1, 49.1 LmW-1 for [Ir(ppy-NPh2)3], and 10.1%, 37.6 cdA-1, 26.1 Lm W-1 for [Ir(ppy-SO2Ph)3]. These results provide a completely new and effective strategy for carrier injection into the electrophosphor to afford high-performance PHOLEDs suitable for various display applications.

Original languageEnglish
Pages (from-to)1830-1841
Number of pages12
JournalChemistry - An Asian Journal
Volume3
Issue number10
DOIs
Publication statusPublished - 6 Oct 2008

Scopus Subject Areas

  • Biochemistry
  • Organic Chemistry

User-Defined Keywords

  • Electron transport
  • Iridium
  • Main group elements
  • Phosphorescence
  • UV/Vis spectroscopy

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