The emitting wavelength and efficiency of a series of blue phosphorescent bis-tridentate iridium complexes have been quantitatively evaluated using comprehensive theoretical approaches. By comparing the effect of different substituent groups in the tridentate ligands, their concrete influence to the radiative and non-radiative process have been analysed. The calculated wavelengths of phosphorescent molecules are in accordance with experimental results. The slightly blue shift in the phosphorescence of complex 1–4 is attributed to the ether link between two aromatic groups as compared to skyblue molecule. The method of calculating radiative decay constant (k_r) and the non-radiative decay constant (k_nr) is verified and can predict the phosphorescent efficiency of iridium complexes in this study. The result shows that introducing ether link leads to the decrease of transition dipole moments, which consequently decreases k_r. On the other hand, comparing with the strong electron attracting group CF₃, k_r and k_nr can both be enhanced by the electron donating group Bu^t. Further analysis of vibrational modes indicates that although spin-orbit coupling (SOC) is important to k_nr, while in this case, a higher reorganization energy at low frequency region determines a faster non-radiative decay process. At last, the inter-system crossing process (ISC) is considered. Unlike experimental speculation, a rate determining step is identified as from S₁ to T₁/T₂/T₃ in different complexes. The present study is expected to provide a theoretical method to evaluate the phosphorescent efficiency of bis-tridentate iridium complexes and investigate the influence of electron donating (attracting) substituent groups.

一系列蓝色磷光双三齿铱配合物的发射波长和效率已使用全面的理论方法进行了定量评估。通过比较三齿配体中不同取代基的作用，已分析了它们对辐射和非辐射过程的具体影响。磷光分子的计算波长与实验结果一致。与天蓝色分子相比，复合物1-4的磷光中的轻微蓝移是由于两个芳族基团之间的醚键所致。辐射衰减常数（k _r）和非辐射衰减常数（k _nr）的计算方法）已经过验证，可以预测本研究中铱配合物的磷光效率。结果表明，引入醚键会导致跃迁偶极矩的减小，从而减小k _r。另一方面，与强电子吸引基团CF _3相比，k _r和k _nr都可以通过给电子基团Bu ^t来增强。振动模式的进一步分析表明，尽管自旋轨道耦合（SOC）对于k _nr很重要，但在这种情况下，低频区域的重组能量较高，决定了更快的非辐射衰减过程。最后，考虑了系统间穿越过程（ISC）。与实验推测不同，速率确定步骤被识别为在不同络合物中从S ₁至T ₁ / T ₂ / T ₃。本研究有望为评估双三齿铱配合物的磷光效率和研究给电子（吸引）取代基的影响提供理论方法。