Correlating Experimental Photophysical Properties of Iridium(III) Complexes to Spin Orbit Coupled TDDFT Predictions
Correlating Experimental Photophysical Properties of Iridium(III) Complexes to Spin Orbit Coupled TDDFT Predictions
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DOI：
10.1021/jp410576a
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发表时间：
2013-12-05
影响因子：
3.7
通讯作者：
Dobbs, Kerwin D.
中科院分区：
文献类型：
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作者：
Younker, Jarod M.;Dobbs, Kerwin D.
Ir(III) 配合物是有效的磷光发射体。三重态流形和单重态流形之间的过渡偶极矩在形式上是自旋禁止的。然而，由 Ir 中的高角动量轨道引起的自旋轨道耦合 (SOC) 有效地将三重态流形与更高能量的单重态混合，从而增加了跃迁概率。零阶相对论近似 (ZORA) 内的自旋轨道耦合瞬态密度泛函 (TDDFT) 计算用于研究九种复合物，其发射范围为 450 至 630 nm，量子效率为 0.1-0.9。我们发现使用单态基态几何结构来计算辐射率与实验具有最佳的相关性。我们还表明，三重态流形中三个子能级的相等热布居足以理解 300 K 下的速率。我们发现，发射能量和辐射速率在 TD-B3LYP/TZP/DZP//BP86/TZ2P/TZP 理论水平上得到了最好的再现，其中为 Ir 提供了更大的基组。
Ir(III) complexes are efficient phosphorescent emitters. The transition dipole moment between the triplet and singlet manifolds is formally spin forbidden. However, spin-orbit coupling (SOC), induced by the high angular momentum orbitals in Ir, efficiently mixes the triplet manifold with higher-energy singlets, increasing the transition probability. Spin-orbit coupled time-dependent density functional (TDDFT) calculations within the zero-order relativistic approximation (ZORA) are used to study nine complexes that have a range of emissions from 450 to 630 nm and quantum efficiencies of 0.1-0.9. We find that using the singlet ground-state geometry to calculate radiative rates produces the best correlation with experiment. We also show that the equal thermal population of the three sublevels in the triplet manifold is sufficient to understand rates at 300 K. We find that emission energies and radiative rates are best reproduced at the TD-B3LYP/TZP/DZP//BP86/TZ2P/TZP level of theory, where the larger basis set is supplied for Ir.