Conformational Dynamics Guides Coherent Exciton Migration in Conjugated Polymer Materials: First-Principles Quantum Dynamical Study
Conformational Dynamics Guides Coherent Exciton Migration in Conjugated Polymer Materials: First-Principles Quantum Dynamical Study
复制标题
DOI：
10.1103/physrevlett.120.227401
复制
发表时间：
2018-05-31
影响因子：
8.6
通讯作者：
Burghardt, Irene
中科院分区：
文献类型：
--
作者：
Binder, Robert;Lauvergnat, David;Burghardt, Irene
为了阐明半导体聚合物中基本激子输运步骤的争议性质，我们报道了在单链寡聚噻吩链段中光致激子迁移的高维量子动力学模拟。采用了一种新的第一性原理参数化Frenkel J聚合哈密顿量，大大超出了标准的Frenkel-Holstein哈密顿量。从光激发产生的非平衡态出发，这些模拟提供了在低温下超快的两个时间尺度过程的证据，涉及几十飞秒（fs）内的激子极化子形成，然后在类似于400 fs的时间尺度上扭转弛豫。第二步是激子迁移的驱动力，因为初始共轭断裂被动态平坦化去除。的量子相干性质的基本激子迁移步骤是一致的实验观察突出的相关性和振动相干性质的超快时间尺度上的动态。
We report on high-dimensional quantum dynamical simulations of photoinduced exciton migration in a single-chain oligothiophene segment, in view of elucidating the controversial nature of the elementary exciton transport steps in semiconducting polymers. A novel first-principles parametrized Frenkel J aggregate Hamiltonian is employed that goes significantly beyond the standard Frenkel-Holstein Hamiltonian. Departing from a nonequilibrium state created by photoexcitation, these simulations provide evidence of an ultrafast two-timescale process at low temperatures, involving exciton-polaron formation within tens of femtoseconds (fs), followed by torsional relaxation on an similar to 400 fs timescale. The second step is the driving force for exciton migration, as initial conjugation breaks are removed by dynamical planarization. The quantum coherent nature of the elementary exciton migration step is consistent with experimental observations highlighting the correlated and vibrationally coherent nature of the dynamics on ultrafast timescales.