Density functional theory and time-dependent density functional study a series of iridium complexes with low-efficiency roll-off properties QinZheng-Kun ChiHao-Yuan XiGuo-Qing LiuXiang SongMing-Xing WangJia ZhangYong-Ling Shi-Quan ZhangHong-Jie 2020 <p>A series of blue phosphorescent heteroleptic cyclometalated Ir(III) complexes with mesitylphenyl-imidazole ligands for organic light-emitting devices have been theoretically studied. We want to find their electronic structures, spectroscopic properties, and application value for organic light-emitting devices. (fppz)<sub>2</sub>Ir(acac), (fppz)<sub>2</sub>Ir(tpip), (dfbdp)<sub>2</sub>Ir(fppz), (F-fppz)<sub>2</sub>Ir(acac), (F-fppz)<sub>2</sub>Ir(tpip), and (dfbdp)<sub>2</sub>Ir(F-fppz) are investigated with DFT and TD-DFT approaches, where, for (fppz)<sub>2</sub>Ir(acac), (fppz denotes 2-(5-(trifluoromethyl)-4H-pyrazol-3-yl)pyridine, and acac denotes acetylacetonate); for (fppz)<sub>2</sub>Ir(tpip), tpip denotes tetraphenylimido-diphosphinate; and, for (F-fppz)<sub>2</sub>Ir(acac) and (F-fppz)<sub>2</sub>Ir(tpip), F-fppz denotes 2-(5-fluoro-4H-pyrazol-3-yl)pyridine.</p>