Abstract: | A series of heteroleptic cyclometalated Ir (III) complexes with low‐color‐temperature and low‐efficiency roll‐off properties, which cause a fast reduction in efficiency when the drive current increases, for organic light‐emitting devices are investigated theoretically to explore their electronic structures and spectroscopic properties. The geometries, electronic structures, lowest‐lying singlet absorptions and triplet emissions of (ptpy)2Ir(acac), and the theoretically designed models (ptpy)2Ir(tpip), (F‐ptpy)2Ir(acac), (F‐ptpy)2Ir(tpip), (F2‐ptpy)2Ir(acac) and (F2‐ptpy)2Ir(tpip), are investigated with density functional theory approaches, where ptpy denotes 4‐phenylthieno 3,2‐c] pyridine, acac denotes acetylacetonate, tpip denotes tetraphenylimido‐diphosphinate, F‐ptpy denotes 4‐(3‐fluorophenyl) thieno 3,2‐c] pyridine, and F2‐ptpy denotes 4‐(2,4‐difluorophenyl) thieno 3,2‐c] pyridine. |