Phosphorescent organic light-emitting diodes (PhOLEDs) are leading candidates for displays or lighting technologies. Recently, blue phosphorescent tetradentate Pt(II) complexes have been attracting extensive attention due to their high phosphorescence quantum efficiency and numerous chemical structures on account of flexible ligand frames and modifications. Using quantum chemistry coupled with our thermal vibration correlation function (TVCF) formalism, we investigated the triplet excited state energy surface and the decay processes involving both direct vibrational relaxation and minimum energy crossing point (MECP) via the transition state (³TS) to the ground state (S₀) for 16 recently experimentally reported blue-emitting tetradentate Pt(II) emitters containing fused 5/6/6 metallocycles. We found that (i) in most cases, the direct vibrational relaxation deactivations dominated the triplet non-radiative decay because either the ³TS is too high or the MECP is not reachable. Hence, results from the TVCF formalism agreed well with the experiments for the phosphorescence quantum efficiency; (ii) only when both ³TS and MECP are low, for instance, for PtON1-oMe, deactivations via MECP dominated the triplet non-radiative decay.

中文翻译：

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评估磷光量子效率的计算方案：应用于发蓝光的四齿 Pt(II) 配合物

磷光有机发光二极管 (PhOLED) 是显示器或照明技术的主要候选者。近年来，蓝色磷光四齿Pt( II )配合物因其高磷光量子效率和灵活的配体框架和修饰而引起的众多化学结构引起了广泛关注。使用量子化学结合我们的热振动相关函数 (TVCF) 形式，我们研究了三重激发态能量表面和涉及直接振动弛豫和最小能量交叉点 (MECP) 的衰变过程，通过过渡态 ( ³ TS) 到基态 (S ₀) 用于最近实验报告的 16 个含有稠合 5/6/6 金属环的蓝色四齿铂 ( II ) 发射体。我们发现 (i) 在大多数情况下，直接振动弛豫失活主导了三重态非辐射衰减，因为³ TS 太高或 MECP 无法达到。因此，TVCF 形式的结果与磷光量子效率的实验非常吻合；(ii) 只有当³ TS 和 MECP 都低时，例如，对于 PtON1-oMe，通过MECP 的失活主导了三重态非辐射衰变。