Syntheses, Photophysics, and Application of Iridium(III) Phosphorescent Emitters for Highly Efficient, Long‐Life Organic Light‐Emitting Diodes

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

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Author(s)

  • Tsang-Chi Lee
  • Chiung-Fang Chang
  • Yuan-Chieh Chiu
  • Tzu-Ying Chan
  • Yi-Ming Cheng
  • Chin-Hung Lai
  • Pi-Tai Chou
  • Gene-Hsiang Lee
  • Chen-Han Chien
  • Ching-Fong Shu
  • Jens Leonhardt

Detail(s)

Original languageEnglish
Pages (from-to)742-753
Journal / PublicationChemistry - An Asian Journal
Volume4
Issue number5
Online published28 Apr 2009
Publication statusPublished - 4 May 2009
Externally publishedYes

Abstract

Rational design and synthesis of Ir III complexes (1-3) bearing two cyclometalated ligands (C^N) and one 2- (diphenylphosphino)phenolate chelate (P^O) as well as the corresponding IrIII derivatives (4-6) with only one (C^N) ligand and two P^O chelates are reported, where (C^NH)=phenylpyridine (ppyH), 1-phenylisoquinoline (piqH), and 4-phenylquinazoline (nazoH). Single crystal X-ray diffraction studies of 3 reveal a distorted octahedral coordination geometry, in which two nazo ligands adopt an eclipsed configuration, with the third P^O ligand located trans to the phenyl group of both nazo ligands, confirming the general skeletal pattern for 1-3. In sharp contrast, complex 4 reveals a trans-disposition for the PPh 2 groups, along with the phenolate groups residing opposite the unique cyclometalated ppy ligand, which is the representative structure for 4-6. These Ir III complexes exhibit green-to-red photoluminescence with moderate to high quantum efficiencies in the degassed luid state and bright emission in the solid state. For 1-6, the resolved emission spectroscopy and relaxation dynamics are well rationalized by the computational approach. OLEDs fabricated using 12 wt.% of 3 doped in CBP and with BCP as hole blocking material, give bright electroluminescence with max= 628 nm and CIE xy coordinates (0.65, 0.34). The turn-on voltage is 3.2 V, while the current efficiency and the power efficiency reach 11.2 cd A -11 and 4.5 lm W -1 at 20 mA cm -2. The maximum efficiency reaches 14.7 cd A -1and 6.8 lm W -1 upon switching to TPBI as hole blocking material. For evaluating evice lifespan, the tested device incorporating CuPc as a passivation layer, 3 doped in CTP as an emitting layer, and Alq as hole blocking material, shows a remarkably long lifetime up to 36000 h at an initial luminance of 500 cd m -2

Research Area(s)

  • Density functional calculations, Iridium, Luminescence, OLEDs, Photophysics

Citation Format(s)

Syntheses, Photophysics, and Application of Iridium(III) Phosphorescent Emitters for Highly Efficient, Long‐Life Organic Light‐Emitting Diodes. / Lee, Tsang-Chi; Chang, Chiung-Fang; Chiu, Yuan-Chieh; Chi, Yun; Chan, Tzu-Ying; Cheng, Yi-Ming; Lai, Chin-Hung; Chou, Pi-Tai; Lee, Gene-Hsiang; Chien, Chen-Han; Shu, Ching-Fong; Leonhardt, Jens.

In: Chemistry - An Asian Journal, Vol. 4, No. 5, 04.05.2009, p. 742-753.

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review