Abstract：
The magnetic alignment of molecules, which exploits the anisotropy of diamagnetic susceptibility, provides a clean and versatile approach to the structural manipulation of semiconducting polymers. Here, the magnetic-alignment dynamics of two molecular-weight (MW) batches of a diketopyrrolopyrrole (DPP)-based copolymer (PDVT-8) were investigated. Microstructural characterizations revealed that the magnetically aligned, high-MW (Mn = 53.7 kDa) PDVT-8 film exhibited a higher degree of backbone chain alignment and film crystallinity compared with the low-MW (Mn = 17.6 kDa) PDVT-8 film grown via the same magnetic alignment method. We found that as the MW increases, the degree of preaggregation of the polymer molecules in solution significantly increases and the aggregation mode changes from H-aggregation to J-aggregation through a cooperative assembly mechanism. These events improved the responsiveness of high-MW polymer molecules to magnetic fields. Field-effect transistors based on the magnetic aligned high-MW PDVT-8 films exhibited a 6.8-fold increase in hole mobility compared to the spin-coated films, along with a mobility anisotropy ratio of 12.6. This work establishes a significant correlation among chain aggregation behavior in solution, polymer film microstructures, magnetic responsiveness, and carrier transport performance in donor-acceptor polymer systems.
摘要：
分子的磁性排列，利用反磁化率的各向异性，为半导体聚合物的结构操作提供了一种清洁和通用的方法。这里,研究了两批分子量（MW）的二酮吡咯并吡咯（DPP）基共聚物（PDVT-8）的磁排列动力学。微结构表征表明，磁性排列，高MW（Mn=53.7kDa）PDVT-8膜与通过相同的磁性排列方法生长的低MW（Mn=17.6kDa）PDVT-8膜相比，表现出更高的主链排列度和膜结晶度。我们发现随着MW的增加,聚合物分子在溶液中的预聚集程度显着增加，聚集模式通过协同组装机制从H聚集变为J聚集。这些事件改善了高MW聚合物分子对磁场的响应性。与旋涂薄膜相比，基于磁性取向的高MWPDVT-8薄膜的场效应晶体管的空穴迁移率提高了6.8倍，以及12.6的迁移率各向异性比。这项工作在解决方案中的链聚合行为之间建立了显著的相关性，聚合物薄膜微结构，磁响应，和在供体-受体聚合物体系中的载流子传输性能。
