Iridium(III) Complexes with Orthometalated Quinoxaline Ligands: Subtle Tuning of Emission to the Saturated Red Color
详细信息 查看全文
- 作者：Fu-Ming Hwang ; Hsing-Yi Chen ; Po-Shen Chen ; Chao-Shiuan Liu ; Yun Chi ; Ching-Fong Shu ; Fang-Iy Wu ; Pi-Tai Chou ; Shie-Ming Peng ; and Gene-Hsiang Lee
- 刊名：Inorganic Chemistry
- 出版年：2005
- 出版时间：March 7, 2005
- 年：2005
- 卷：44
- 期：5
- 页码：1344 - 1353
- 全文大小：223K
- 年卷期：v.44,no.5(March 7, 2005)
- ISSN：1520-510X
文摘
Rational design and syntheses of four iridium complexes (1-4) bearing two substituted quinoxalines and an additional5-(2-pyridyl) pyrazolate or triazolate as the third coordinating ligand are reported. Single-crystal X-ray diffractionstudies of 1 reveal a distorted octahedral geometry, in which two dpqx ligands adopt an eclipse configuration, forwhich the quinoxaline N atoms and the C atoms of orthometalated phenyl groups are located at the mutual trans-and cis-positions, respectively. The lowest absorption band for all complexes consists of a mixture of heavy-atomIr(III)-enhanced 3MLCT and 3
* transitions, and the phosphorescent peak wavelength can be fine-tuned to coverthe spectral range of 622-649 nm with high quantum efficiencies. The cyclic voltammetry was measured, showinga reversible, metal-centered oxidation with potentials at 0.76-1.03 V, as well as two reversible reduction waveswith potentials ranging from -1.61 to -2.06 V, attributed to the sequential addition of two electrons to the moreelectron-accepting heterocyclic portion of two distinctive cyclometalated C
N ligands. Complex 1 was used as therepresentative example to fabricate the red-emitting PLEDs by blending it into a PVK-PBD polymer mixture. Thedevices exhibited the characteristic emission profile of 1 with peak maxima located at 640 nm. The maximumexternal quantum efficiency was 3.15% ph/el with a brightness of 1751 cd/m2 at a current density of 67.4 mA/cm2,and the maximum brightness of 7750 cd/m2 was achieved at the applied voltage of 21 V and with CIE coordinatesof (0.64, 0.31).
* transitions, and the phosphorescent peak wavelength can be fine-tuned to coverthe spectral range of 622-649 nm with high quantum efficiencies. The cyclic voltammetry was measured, showinga reversible, metal-centered oxidation with potentials at 0.76-1.03 V, as well as two reversible reduction waveswith potentials ranging from -1.61 to -2.06 V, attributed to the sequential addition of two electrons to the moreelectron-accepting heterocyclic portion of two distinctive cyclometalated CN ligands. Complex 1 was used as therepresentative example to fabricate the red-emitting PLEDs by blending it into a PVK-PBD polymer mixture. Thedevices exhibited the characteristic emission profile of 1 with peak maxima located at 640 nm. The maximumexternal quantum efficiency was 3.15% ph/el with a brightness of 1751 cd/m2 at a current density of 67.4 mA/cm2,and the maximum brightness of 7750 cd/m2 was achieved at the applied voltage of 21 V and with CIE coordinatesof (0.64, 0.31).