Rothermund Mark A, Koehler Stephen J, Vaissier Welborn Valerie
Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24060, United States.
Macromolecules Innovation Institute (MII), Virginia Tech, Blacksburg, Virginia 24061, United States.
Chem Rev. 2024 Dec 11;124(23):13331-13369. doi: 10.1021/acs.chemrev.4c00490. Epub 2024 Nov 25.
Polymer-based electronic devices are limited by slow transport and recombination of newly separated charges. Built-in electric fields, which arise from compositional gradients, are known to improve charge separation, directional charge transport, and to reduce recombination. Yet, the optimization of these fields through the rational design of polymeric materials is not prevalent. Indeed, polymers are disordered and generate nonuniform electric fields that are hard to measure, and therefore, hard to optimize. Here, we review work focusing on the intentional optimization of electric fields in polymeric systems with applications to catalysis, energy conversion, and storage. This includes chemical tuning of constituent monomers, linkers, morphology, etc. that result in stronger molecular dipoles, polarizability or crystallinity. We also review techniques to characterize electric fields in polymers and emerging processing strategies based on electric fields. These studies demonstrate the benefits of optimizing electric fields in polymers. However, rational design is often restricted to the molecular scale, deriving new pendants on, or linkers between, monomers. This does not always translate in strong electric fields at the polymer level, because they strongly depend on the monomer orientation. A better control of the morphology and monomer-to-polymer scaling relationship is therefore crucial to enhance electric fields in polymeric materials.
基于聚合物的电子器件受到新分离电荷传输和复合缓慢的限制。由成分梯度产生的内建电场已知可改善电荷分离、定向电荷传输并减少复合。然而，通过合理设计聚合物材料来优化这些电场的情况并不普遍。实际上，聚合物是无序的，会产生难以测量的非均匀电场，因此难以优化。在此，我们回顾了旨在有意优化聚合物体系中电场并应用于催化、能量转换和存储的研究工作。这包括对构成单体、连接基、形态等进行化学调控，从而产生更强的分子偶极、极化率或结晶度。我们还回顾了表征聚合物中电场的技术以及基于电场的新兴加工策略。这些研究证明了优化聚合物中电场的益处。然而，合理设计通常局限于分子尺度，即在单体上衍生新的侧基或在单体之间引入新的连接基。这并不总能在聚合物层面产生强电场，因为它们在很大程度上取决于单体的取向。因此，更好地控制形态以及单体与聚合物的比例关系对于增强聚合物材料中的电场至关重要。
