Electronic Structures and Spectroscopic Properties of a Novel Iridium (III) Complex with an Ancillary Ligand 2-(4-Trifluoromethyl -2-Hydroxylphenyl)Benzothiazole
LEI Li-Ping1, HAO Yu-Ying1,2**, FAN Wen-Hao1, XU Bing-She2
1Department of Physics and Optoelectronics, Taiyuan University of Technology, Taiyuan 030024 2Key Laboratory of Interface Science and Engineering in Advanced Materials, Taiyuan University of Technology, Taiyuan 030024
Electronic Structures and Spectroscopic Properties of a Novel Iridium (III) Complex with an Ancillary Ligand 2-(4-Trifluoromethyl -2-Hydroxylphenyl)Benzothiazole
LEI Li-Ping1, HAO Yu-Ying1,2**, FAN Wen-Hao1, XU Bing-She2
1Department of Physics and Optoelectronics, Taiyuan University of Technology, Taiyuan 030024 2Key Laboratory of Interface Science and Engineering in Advanced Materials, Taiyuan University of Technology, Taiyuan 030024
摘要Iridium (III) complexes with 2−phenylpyridine (ppy) have been demonstrated as a type of promising phosphorescence dopant in emitting layers of organic light emitting diodes (OLEDs). In most iridium (III) complexes, there exist the strong spin−orbit coupling between π−orbitals of cyclometalated ligands and 5d orbitals of the centric iridium. We study a novel iridium (III) complex (ppy)2Ir(4−TfmBTZ) with ppy as cyclometalated ligands and 2-(4-trifluoromethyl-2-hydroxylphenyl)benzothiazole (4-TfmBTZ) as an ancillary ligand using the Gaussian 03 program. The geometries, electronic structures and spectroscopic properties of this iridium (III) complex are investigated by density functional theory (DFT) and time−dependent density functional theory (TD-DFT). The results show that the spin-orbit coupling occurs not only between ppy and iridium atom but also between 4-TfmBTZ and iridium atom in this complex. The highest occupied molecular orbital is dominantly localized on the Ir atom and 4-TfmBTZ ligand, while the lowest unoccupied molecular orbital on 4-TfmBTZ ligand. The triplet lowest-lying transition is attributed to the Ir-to-4-TfmBTZ charge-transfer (3MLCT) transition while the sub−low-lying transitions are assigned to the 3MLCT transitions of Ir(ppy)2. The nature of the lowest unoccupied orbital changes from ppy−localized to 4-TfmBTZ-localized and reveals that phosphorescent color of Ir(III) complex can be controlled by the ancillary ligand and substituent.
Abstract：Iridium (III) complexes with 2−phenylpyridine (ppy) have been demonstrated as a type of promising phosphorescence dopant in emitting layers of organic light emitting diodes (OLEDs). In most iridium (III) complexes, there exist the strong spin−orbit coupling between π−orbitals of cyclometalated ligands and 5d orbitals of the centric iridium. We study a novel iridium (III) complex (ppy)2Ir(4−TfmBTZ) with ppy as cyclometalated ligands and 2-(4-trifluoromethyl-2-hydroxylphenyl)benzothiazole (4-TfmBTZ) as an ancillary ligand using the Gaussian 03 program. The geometries, electronic structures and spectroscopic properties of this iridium (III) complex are investigated by density functional theory (DFT) and time−dependent density functional theory (TD-DFT). The results show that the spin-orbit coupling occurs not only between ppy and iridium atom but also between 4-TfmBTZ and iridium atom in this complex. The highest occupied molecular orbital is dominantly localized on the Ir atom and 4-TfmBTZ ligand, while the lowest unoccupied molecular orbital on 4-TfmBTZ ligand. The triplet lowest-lying transition is attributed to the Ir-to-4-TfmBTZ charge-transfer (3MLCT) transition while the sub−low-lying transitions are assigned to the 3MLCT transitions of Ir(ppy)2. The nature of the lowest unoccupied orbital changes from ppy−localized to 4-TfmBTZ-localized and reveals that phosphorescent color of Ir(III) complex can be controlled by the ancillary ligand and substituent.
LEI Li-Ping;HAO Yu-Ying;**;FAN Wen-Hao;XU Bing-She
. Electronic Structures and Spectroscopic Properties of a Novel Iridium (III) Complex with an Ancillary Ligand 2-(4-Trifluoromethyl -2-Hydroxylphenyl)Benzothiazole[J]. 中国物理快报, 2011, 28(6): 63101-063101.
LEI Li-Ping, HAO Yu-Ying, **, FAN Wen-Hao, XU Bing-She
. Electronic Structures and Spectroscopic Properties of a Novel Iridium (III) Complex with an Ancillary Ligand 2-(4-Trifluoromethyl -2-Hydroxylphenyl)Benzothiazole. Chin. Phys. Lett., 2011, 28(6): 63101-063101.
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2011, Vol. 28 
