Iridium(I) pyridyl azolate complexes with saturated red metal-to-ligand charge transfer phosphorescence; Fundamental and potential applications in organic light-emitting diodes

Chung Hong Fang, Yao Lun Chen, Cheng Han Yang, Yun Chi*, Yu Shan Yeh, Elisa Y. Li, Yi Ming Cheng, Chia Jung Hsu, Pi Tai Chou, Chin Ti Chen

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

27 Citations (Scopus)

Abstract

Preparation of a new series of neutral metal complexes [(cod)Ir-(fppz)] (1), [(cod)Ir(bppz)] (2), [(cod)Ir(fptz)] (3) and [(cod)Ir(bptz)] (4). bearing one cod ligand and a pyridyl azolate chelate are reported. A single-crystal X-ray diffraction study of 3 reveals the expected distorted square-planar geometry. The lowest absorption band consists of Ir1 atom increased triplet dπ-→* transitions (3MLCT), the assignment of which is firmly supported by the theoretical approaches. Complexes 1-4 exhibit weak phosphorescence in degassed solution at room temperature, whereas much more intense, solid-state phosphorescence appears in the range 622-649 nm. The pure MLCT emission was used as a prototypical model to address its remarkable spectral differences from the IrIII isoquinoline pyrrolide complex (5), which has mainly 3ππ phosphorescence. Complex 3 was used as a dopant to fabricate red-emitting phosphorescent organic light-emitting diodes (OLEDs). For the 7% doped device, a maximum brightness of 3010 cdm-2 was achieved at an applied voltage of 15 V and with CIE coordinates of (0.56, 0.33). demonstrating for the first time the potential of neutral Ir1 complexes in OLED applications.

Original languageEnglish
Pages (from-to)2686-2694
Number of pages9
JournalChemistry - A European Journal
Volume13
Issue number9
DOIs
Publication statusPublished - 2007
Externally publishedYes

Keywords

  • Cyclooctene
  • Iridium
  • Phosphorescence
  • Photochemistry
  • Pyridyl azolate

ASJC Scopus subject areas

  • Catalysis
  • Organic Chemistry

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