Lee Franklin L, Barati Farimani Amir, Gu Kevin L, Yan Hongping, Toney Michael F, Bao Zhenan, Pande Vijay S
Department of Chemical Engineering, Stanford University , Stanford, California 94305, United States.
Department of Chemistry, Stanford University , Stanford, California 94305, United States.
J Phys Chem Lett. 2017 Nov 16;8(22):5479-5486. doi: 10.1021/acs.jpclett.7b02360. Epub 2017 Oct 30.
Conjugated polymers are the key material in thin-film organic optoelectronic devices due to the versatility of these molecules combined with their semiconducting properties. A molecular-scale understanding of conjugated polymers is important to the optimization of the thin-film morphology. We examine the solution-phase behavior of conjugated isoindigo-based donor-acceptor polymer single chains of various chain lengths using atomistic molecular dynamics simulations. Our simulations elucidate the transition from a rod-like to a coil-like conformation from an analysis of normal modes and persistence length. In addition, we find another transition based on the solvent environment, contrasting the coil-like conformation in a good solvent with a globule-like conformation in a poor solvent. Overall, our results provide valuable insights into the transition between conformational regimes for conjugated polymers as a function of both the chain length and the solvent environment, which will help to accurately parametrize higher level models.
共轭聚合物是薄膜有机光电器件中的关键材料，这是由于这些分子具有多功能性且兼具半导体特性。对共轭聚合物在分子尺度上的理解对于优化薄膜形态至关重要。我们使用原子分子动力学模拟研究了不同链长的基于异吲哚啉酮的共轭供体-受体聚合物单链在溶液相中的行为。我们的模拟通过对正常模式和持久长度的分析阐明了从棒状构象到线圈状构象的转变。此外，我们基于溶剂环境发现了另一种转变，将良溶剂中的线圈状构象与不良溶剂中的球状构象进行了对比。总体而言，我们的结果为共轭聚合物构象状态之间的转变提供了有价值的见解，该转变是链长和溶剂环境的函数，这将有助于准确地为更高层次的模型设定参数。
