Solid-state effect plays an important role in defining the nature of excited states for thermally activated delayed fluorescence (TADF) molecules and further affects their luminescence properties. Theoretical investigation of photophysical properties with explicit consideration of intermolecular interactions in solid phase, is highly desired. In this work, the luminescent properties of new TADF molecule SBF-BP-DMAC with aggregation induced emission (AIE) feature are theoretically studied both in solution and solid phase. Solvent environment effect in Tetrahydrofuran (THF) is simulated by polarizable continuum model (PCM) and solid-state effect is considered by the combined quantum mechanics and molecular mechanics (QM/MM) method. By combing thermal vibration correlation function (TVCF) theory with first principles calculation, excited state energy consumption process is investigated. Our results show that the calculated prompt fluorescence efficiency, delayed fluorescence efficiency and total fluorescence efficiency in THF is 3.0%, 0.4‰ and 3.0% respectively, and corresponding value increases to 14.4%, 31.5% and 45.9% for molecule in solid phase, this verifies the AIE feature. To detect the inner mechanisms, the geometrical structures, Huang-Rhys (HR) factors and reorganization energies as well as excited state transition properties are analyzed. Decreased HR factor and reorganization energy are found in solid phase, this is caused by the restricted torsion motion of DMAC unit in rigid environment. Thus, non-radiative energy consumption process is suppressed and enhanced fluorescence efficiency is found in the solid phase. Moreover, the smaller energy gap between S₁ and T₁ in the solid state than that in THF, is more conducive for reverse intersystem crossing process and further improves the efficiency. This work provides reasonable explanation for the experimental measurements and reveals the inner perspectives for AIE and TADF mechanisms, which is advantageous to develop new non-doped OLEDs with advanced feature.

固态效应在定义热激活延迟荧光（TADF）分子的激发态性质方面起着重要作用，并进一步影响其发光特性。强烈希望对光物理性质进行理论研究，并明确考虑固相中的分子间相互作用。在这项工作中，理论上研究了在溶液相和固相中具有聚集诱导发射（AIE）特征的新型TADF分子SBF-BP-DMAC的发光性质。通过极化连续体模型（PCM）模拟了四氢呋喃（THF）中的溶剂环境效应，并结合了量子力学和分子力学（QM / MM）方法考虑了固态效应。通过将热振动相关函数（TVCF）理论与第一原理计算相结合，研究了激发态能耗过程。我们的结果表明，计算出的THF中快速荧光效率，延迟荧光效率和总荧光效率分别为3.0％，0.4‰和3.0％，固相分子的相应值分别增加到14.4％，31.5％和45.9％，这验证AIE功能。为了检测内部机理，分析了几何结构，黄-Rhys（HR）因子和重组能以及激发态跃迁特性。在固相中发现HR因子和重组能降低，这是由于DMAC单元在刚性环境中受限制的扭转运动引起的。因此，抑制了非辐射能量消耗过程并且在固相中发现增强的荧光效率。而且，S之间的能隙更小固体状态的₁和T ₁比THF中的状态更有利于逆系统间交叉过程，并进一步提高了效率。这项工作为实验测量提供了合理的解释，并揭示了AIE和TADF机制的内部观点，这有利于开发具有先进功能的新型非掺杂OLED。