標題: Syntheses, Photophysics, and Application of Iridium(III) Phosphorescent Emitters for Highly Efficient, Long-Life Organic Light-Emitting Diodes
作者: 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
應用化學系
Department of Applied Chemistry
關鍵字: density functional calculations;iridium;luminescence;OLEDs;photophysics
公開日期: 2009
摘要: Rational design and synthesis of Ir(III) complexes (1-3) bearing two cyclometalated ligands (C boolean AND N) and one 2-(diphenylphosphino)phenolate chelate (P boolean AND O) as well as the corresponding Ir(III) derivatives (4-6) with only one (C boolean AND N) ligand and two P boolean AND O chelates are reported, where (C boolean AND 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 boolean AND 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 fluid 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 lambda(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 11.2cd A(-1) and 4.5 lm W(-1) at 20 mA cm(-2). The maximum efficiency reaches 14.7 cd A(-1) and 6.8 lm W(-1) upon switching to TPBI as hole blocking material. For evaluating device lifespan, the tested device incorporating CuPc as a passivation layer, 3 doped in CTP as an emitting layer, and BAlq as hole blocking material, shows a remarkably long lifetime up to 36 000 h at an initial luminance of 500 cd m(-2).
URI: http://hdl.handle.net/11536/7816
http://dx.doi.org/10.1002/asia.200800468
ISSN: 1861-4728
DOI: 10.1002/asia.200800468
期刊: CHEMISTRY-AN ASIAN JOURNAL
Volume: 4
Issue: 5
起始頁: 742
結束頁: 753
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