Tetrafluorinated phenylpyridine based heteroleptic iridium(iii) complexes for efficient sky blue phosphorescent organic light-emitting diodes

Zhao Chen, Songwut Suramitr, Nianyong Zhu, Cheuk Lam Ho, Supa Hannongbua, Shuming Chen (Corresponding Author), Wai Yeung Wong (Corresponding Author)

Research output: Journal article publicationJournal articleAcademic researchpeer-review

8 Citations (Scopus)


It is one of the most difficult and challenging targets to achieve blue phosphorescent organic light-emitting diodes. Herein, we employ tetrafluorinated 2-phenylpyridine (F4ppy) as a cyclometalated ligand, in which the tetrafluorophenyl group contributes to the stabilization of the highest occupied molecular orbital (HOMO) of its iridium(iii) complex. Meanwhile, N-heterocyclic carbene (NHC) and acidic pyrazolyl-pyridine (fppz) moieties as ancillary ligands are used to keep the lowest unoccupied molecular orbitals (LUMOs) of the phosphors relatively unchanged. Therefore, the energy gap between the HOMO and LUMO is enlarged and two sky blue emissive iridium(iii) phosphors, named (F4ppy)2Ir(CF3-pei) (Ir-1) and (F4ppy)2Ir(fppz) (Ir-2), are achieved. Strong phosphorescent emission at a wavelength of around 460 nm with a photoluminescence quantum yield of around 60% is observed in solution for these two phosphors. Moreover, the organic light-emitting devices made from Ir-1 and Ir-2 exhibit high-efficiencies, affording peak current efficiencies (CEs) of 47.6 and 45.5 cd A-1 with external quantum efficiencies (EQEs) of 20.6% and 19.6%, respectively.

Original languageEnglish
Pages (from-to)2551-2557
Number of pages7
JournalJournal of Materials Chemistry C
Issue number7
Publication statusPublished - 21 Feb 2020

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Chemistry

Cite this