Homoleptic Cyclometalated Iridium Complexes with Highly Efficient Red Phosphorescence and Application to Organic Light-Emitting Diode
Top Cited Papers
- 27 September 2003
- journal article
- research article
- Published by American Chemical Society (ACS) in Journal of the American Chemical Society
- Vol. 125 (42) , 12971-12979
- https://doi.org/10.1021/ja034732d
Abstract
Phosphorescence studies of a series of facial homoleptic cyclometalated iridium(III) complexes have been carried out. The complexes studied have the general structure Ir(III)(C−N)3, where (C−N) is a monoanionic cyclometalating ligand: 2-(5-methylthiophen-2-yl)pyridinato, 2-(thiophen-2-yl)-5-trifluoromethylpyridinato, 2,5-di(thiophen-2-yl)pyridinato, 2,5-di(5-methylthiophen-2-yl)pyridinato, 2-(benzo[b]thiophen-2-yl)pyridinato, 2-(9,9-dimethyl-9H-fluoren-2-yl)pyridinato, 1-phenylisoquinolinato, 1-(thiophen-2-yl)isoquinolinato, or 1-(9,9-dimethyl-9H-fluoren-2-yl)isoquinolinato. Luminescence properties of all the complexes at 298 K in toluene are as follows: quantum yields of phosphorescence Φp = 0.08−0.29, emission peaks λmax = 558−652 nm, and emission lifetimes τ = 0.74−4.7 μs. Bathochromic shifts of the Ir(thpy)3 family [the complexes with 2-(thiophen-2-yl)pyridine derivatives] are observed by introducing appropriate substituents, e.g., methyl, trifluoromethyl, or thiophen-2-yl. However, Φp of the red emissive complexes (λmax > 600 nm) becomes small, caused by a significant decrease of the radiative rate constant, kr. In contrast, the complexes with the 1-arylisoquinoline ligands are found to have marked red shifts of λmax and very high Φp (0.19−0.26). These complexes are found to possess dominantly 3MLCT (metal-to-ligand charge transfer) excited states and have kr values approximately 1 order of magnitude larger than those of the Ir(thpy)3 family. An organic light-emitting diode (OLED) device that uses Ir(1-phenylisoquinolinato)3 as a phosphorescent dopant produces very high efficiency (external quantum efficiency ηex = 10.3% and power efficiency 8.0 lm/W at 100 cd/m2) and pure-red emission with 1931 CIE (Commission Internationale de L'Eclairage) chromaticity coordinates (x = 0.68, y = 0.32).Keywords
This publication has 36 references indexed in Scilit:
- Luminescent Mononuclear and Dinuclear Iridium(III) Cyclometalated Complexes Immobilized in a Polymeric Matrix as Solid-State Oxygen SensorsAnalytical Chemistry, 1998
- Square Planar (SP-4) and Octahedral (OC-6) Complexes of Platinum(II) and -(IV) with Predetermined Chirality at the Metal CenterInorganic Chemistry, 1996
- Palladium-Catalyzed Cross-Coupling Reactions of Organoboron CompoundsChemical Reviews, 1995
- Luminescence characterizations of cyclometalated rhenium(I) carbonyl complexesInorganic Chemistry, 1993
- A new synthetic route to the preparation of a series of strong photoreducing agents: fac-tris-ortho-metalated complexes of iridium(III) with substituted 2-phenylpyridinesInorganic Chemistry, 1991
- Vibrational spectroscopic study of the temperature- and pressure-induced phase transition of norbornyleneThe Journal of Physical Chemistry, 1991
- Photochemistry of the orthometalated cis-bis[2-(2-thienyl)pyridine]platinum(II) complex in halocarbon solventsJournal of the American Chemical Society, 1987
- Photochemistry of metal coordination complexes: metal to ligand charge transfer excited statesPure and Applied Chemistry, 1986
- Gas-phase photofragmentation of chromium hexacarbonyl: time-resolved infrared spectrum and decay kinetics of "naked" chromium pentacarbonylJournal of the American Chemical Society, 1985
- A carbon-bonded tris(2,2'-bipyridine)iridium(III) complex: (2,2'-bipyridinyl-C3,N')bis(2,2'-bipyridine-N,N')iridium(III) perchlorate-water (3/1)Inorganic Chemistry, 1983