Theoretical study on the electronic structures and optical properties of blue-green and blue phosphorescent iridium(III) complexes with tetraphenylimidodiphosphinate ligand

Authors

  • Xiao-Hong Shang,

    1. State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, People's Republic of China
    2. College of Chemistry and Life Science, Changchun University of Technology, Changchun, People's Republic of China
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  • Yu-Qi Liu,

    1. State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, People's Republic of China
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  • Juan-Juan Su,

    1. State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, People's Republic of China
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  • Godefroid Gahungu,

    1. Département de Chimie, Unité de Chimie Théorique et Modélisation Moléculaire, Faculté des Sciences, Université du Burundi, Bujumbura, Burundi
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  • Xiao-Chun Qu,

    1. State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, People's Republic of China
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  • Zhi-Jian Wu

    Corresponding author
    1. State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, People's Republic of China
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Abstract

The electronic structures and photophysical properties of five iridium(III) complexes Ir(tfmppy)2(tpip) (1), Ir(dfppy)2(tpip) (2), Ir(afCNppy)2(tpip) (3), Ir(CNpyN3)2(tpip) (4), and Ir(2fphpta)2(tpip) (5) [where tfmppy = 4-trifluoromethylphenylpyridine; dfppy =4,6-difluorophenylpyridine; afCNppy = 6-fluoro-4-octyloxy-5-cyano-phenylpyridine; CNpyN3 = 2-(4-cyano-phenyl)-[1,2,3]-triazole; 2fphpta=2-(2,6-difluoro-phenyl-[1,2,4]-triazol-3-yl)-pyridine; tpip=tetraphenylimido-diphosphinate] have been investigated by using density functional theory (DFT) methods and time-dependent DFT ones, aiming at elucidating the influences of different substituents and cyclometalated ligands on the emission properties and quantum yield. The calculated results revealed that the different substituents in 1-3 have a great influence on the energy levels, in particular highest occupied molecular orbital. Meanwhile, we have also get a further insight into the reason for different phosphorescence quantum yields of the studied complexes. The higher quantum yield (Φ) reported for 1 was found to be closely related to both its smaller S1–T1 splitting energy ( inline image) and larger transition electric dipole moment ( inline image) upon the S0 → S1 transition. Complex 5 is expected to be a potential candidate for blue-emitting material with good organic light-emitting diodes performances. We propose that the optical properties of this class of materials can be tuned by the modifications of the cyclometalated ligands. © 2013 Wiley Periodicals, Inc.

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