Photoinduced excitonic dynamics plays an essential role in the solar energy conversion of organic solar cells. Following our previous work [J. Phys. Chem. C 121 (2017) 27263] on the energy transfer of the 2-[[7-(5-N,N-ditolylaminothiophen-2-yl)-2,1,3-benzothiadiazol-4-yl]methylene]malononitrile (DTDCTB) dimer, we try to understand the role of the intermolecular charge-transfer (CT) electronic states in the excitonic dynamics. When the CT states lie higher than local excited (LE) states and the LE/CT couplings are weak, the CT state plays a minor role. When the LE/CT couplings are strong enough, the CT states start to be unneglectable. When the CT states show lower energies than LE states, the CT states become important. In addition, the near-resonance condition may appear in the excitonic dynamics, resulting in the low-frequency oscillation pattern in the time-dependent electronic populations. This work provides the interesting insight on the role of the CT states in the excitonic dynamics of organic photovoltaic systems.

光诱导的激子动力学在有机太阳能电池的太阳能转化中起着至关重要的作用。遵循我们以前的工作[J. 物理 化学 C 121（2017）27263]，关于2-[[7-（5-N，N-二糖基氨基噻吩-2-基）-2,1,3-苯并噻二唑-4-基]亚甲基]丙二腈（DTDCTB）的能量转移）二聚体，我们试图了解分子间电荷转移（CT）电子态在激子动力学中的作用。当CT状态高于局部激发（LE）状态且LE / CT耦合较弱时，CT状态起着次要作用。当LE / CT耦合足够牢固时，CT状态开始变得不可忽略。当CT状态显示的能量低于LE状态时，CT状态变得很重要。另外，在激子动力学中可能会出现近共振情况，导致在时间相关的电子族群中产生低频振荡模式。这项工作对CT状态在有机光伏系统的激子动力学中的作用提供了有趣的见解。