The geometry structures, electronic structures, absorption, and phosphorescence properties of four tris-cyclometalated iridium(III) complexes IrL3, that is, 1 (L = 2-(4,6-difluorophenyl)pyridinato,N,C 2′), 2 (L = 2-(4,6-difluorophenyl)pyridinato,N,C 2′-5-phenyl), 3 (L = 2-(4,6-difluorophenyl)pyridinato,N,C 2′-5-(p-tolyl)), and 4 (L = 2-(4,6-difluorophenyl) benzo[h]isoquinoline), have been investigated under the framework of the time-dependent density functional theory approach. For assumed 2 and 3, the emission energies are nearly the same, consistent with their similar HOMO-LUMO energy gaps. The calculated lowest energy emissions are localized at 523, 605, 616, and 642 nm for 1, 2, 3, and 4, respectively. Calculations of ionization potential and electron affinity were used to evaluate the injection abilities of holes and electrons into these complexes. For 2, the calculated results evidenced a larger 3MLCT contribution (27.0%), a large S0 → S1 transition dipole moment (μS1) of 1.43 D, and a small S1-T1 splitting energy (ΔES1-T1) of 0.33 eV, which could result in a large radiative decay rate (kr). We hope that this theoretical work can provide a suitable guide to the future design and synthesis of novel phosphorescent materials for use in the organic light-emitting diodes.
All Science Journal Classification (ASJC) codes
- Organic Chemistry