采用非绝热动力学模拟探究溶剂效应对桨-轮形状的给体-受体复合物的激发态弛豫动力学的影响

充分理解给体-受体复合物的激发态动力学在实验和理论上都具有非常重要的意义. 本文首次结合电子结构计算和非绝热动力学模拟，探索了最近合成的一个桨-轮形状的给体-受体复合物的光致动力学过程，该复合物由三个氟硼二吡咯基团和一个六氧杂并三苯构成. 根据计算结果，得出结论，桨-轮形状的给体-受体复合物共轭物在激发时将被提升到氟硼二吡咯片段的局部激发状态，然后发生超快局部激发电子态到电荷转移电子态的激子转移. 与先前实验工作中提出的光致电子转移机理不同，这种激子转移过程伴随着从氟硼二吡咯基团到六氧杂并三苯基团上的空穴. 此外，还发现溶剂效应在该体系的光致动力学中起着重要作用. 具体而言，强极性的乙腈溶剂加速了空穴转移动力学，这可以归因于溶剂对电荷转移状态的显著影响，即局部激发和电荷转移激子之间的能隙大大减小，而与此同时非绝热耦合增加，这两个因素都可以促进空穴转移过程. 目前的工作不仅为桨-轮形状的给体-受体复合物的潜在光诱导机制提供了有价值的见解，而且有助于未来设计具有更好光电性能的新型给体-受体复合物.

Solvent E ects on Excited-State Relaxation Dynamics of Paddle-Wheel BODIPY-Hexaoxatriphenylene Conjugates: Insights from Non-adiabatic Dynamics Simulations

Understanding the excited state dynamics of donor-acceptor (D-A) complexes is of fundamental importance both experimentally and theoretically. Herein, we have first explored the photoinduced dynamics of a recently synthesized paddle-wheel BODIPY-hexaoxatriphenylene (BODIPY is the abbreviation for BF₂-chelated dipyrromethenes) conjugates D-A complexes with the combination of both electronic structure calculations and nonadiabatic dynamics simulations. On the basis of computational results, we concluded that the BODIPY-hexaoxatriphenylene (BH) conjugates will be promoted to the local excited (LE) states of the BODIPY fragments upon excitation, which is followed by the ultrafast exciton transfer from LE state to charge transfer (CT). Instead of the photoinduced electron transfer process proposed in previous experimental work, such a exciton transfer process is accompanied with the photoinduced hole transfer from BODIPY to hexaoxatriphenylene. Additionally, solvent e ects are found to play an important role in the photoinduced dynamics. Specifically, the hole transfer dynamics is accelerated by the acetonitrile solvent, which can be ascribed to significant influences of the solvents on the charge transfer states, i.e. the energy gaps between LE and CT excitons are reduced greatly and the non-adiabatic couplings are increased in the meantime. Our present work not only provides valuable insights into the underlying photoinduced mechanism of BH, but also can be helpful for the future design of novel donor-acceptor conjugates with better optoelectronic performance.