title: Theoretical study on a series of iridium complexes with low efficiency roll-off property.
abstract: A series of heteroleptic cyclometalated Ir (III) complexes for OLEDs application have been investigated theoretically to explore their electronic structures and spectroscopic properties. The geometries, electronic structures, and the lowest-lying singlet absorptions and triplet emissions of (piq)₂Ir(acac) (labeled 1) and theoretically designed models (piq)₂Ir(dpis) (labeled 2), (4Fpiq)₂Ir(dpis) (labeled 3), (4F5M-piq)₂Ir(dpis) (labeled 4), (4,5-2F-piq)₂Ir(dpis) (labeled 5) and (5-F-piq)₂Ir(dpis) (labeled 6) were investigated with density functional theory (DFT)-based approaches, where, piq=1-phenylisoquinolato, acac=acetylacetonate and dpis=diphenylimidodisilicate. Their structures in the ground and excited states have been optimized at the DFT/B3LYP/LANL2DZ and TDDFT/B3LYP/LANL2DZ levels, and the lowest absorptions and emissions were evaluated at B3LYP and M062X level of theory, respectively. Furthermore, the energy-transfer mechanism of these complexes also be analyzed here, and the result shown that the complexes 1-6 are having the low efficiency roll-off property. Except that, the oscillator strength analyze shown that the complexes 2-6, which were designed by theory, are suitable for OLED since their high oscillator strength property.
authors.affiliation: College of Information Technology, Jilin Normal University, Siping 136000, People's Republic of China.
authors.forename: Ming-Xing
authors.initials: MX
authors.lastname: Song
authors.affiliation: College of Information Technology, Jilin Normal University, Siping 136000, People's Republic of China.
authors.forename: Guo-Feng
authors.initials: GF
authors.lastname: Wang
authors.affiliation: College of Information Technology, Jilin Normal University, Siping 136000, People's Republic of China.
authors.forename: Jin
authors.initials: J
authors.lastname: Wang
authors.affiliation: College of Information Technology, Jilin Normal University, Siping 136000, People's Republic of China.
authors.forename: Yu-Hai
authors.initials: YH
authors.lastname: Wang
authors.affiliation: Institute of Theoretical Chemistry, State Key Laboratory of Theoretical and Computational Chemistry, Jilin University, Changchun 130023, People's Republic of China. Electronic address: baifq@jlu.edu.cn.
authors.forename: Fu-Quan
authors.initials: FQ
authors.lastname: Bai
authors.affiliation: College of Information Technology, Jilin Normal University, Siping 136000, People's Republic of China. Electronic address: Qin_ZhengKun@126.com.
authors.forename: Zheng-Kun
authors.initials: ZK
authors.lastname: Qin
mesh_terms: D056831:Coordination Complexes / Q000737:chemistry*; D004583:Electrons; D007495:Iridium / Q000737:chemistry*; D008958:Models, Molecular; D011789:Quantum Theory
chemical_list: D056831:Coordination Complexes; D007495:Iridium
keywords: Efficiency roll-off; Excited state; Ir(III)-complex; OLEDs; TD-DFT