A New Design Paradigm in Low Band Gap Conjugated Polymers

有了这个奖项，化学系的大分子、超分子和纳米化学项目资助了塞思·C·北达科他州州立大学化学与生物化学系的Rasmussen博士的论文，以促进对共轭聚合物结构-功能关系的基本理解。 共轭聚合物是长链有机分子。与硅等传统半导体非常相似，当施加电压（例如晶体管）或光（例如太阳能电池）时，这些聚合物可以变得导电。 该团队为构建新型共轭聚合物创造了设计策略，这些聚合物在有机电子，光电子和有机发光二极管中具有潜在的应用。 除了传统的合成技术，计算建模用于评估潜在的聚合物结构，并预测其电子性质。与这项研究相关的更广泛的活动集中在通过大学的自然项目与美国土著大学的联系上。 该团队还通过记录和传播有关共轭聚合物起源和发展的新历史出版物，为聚合物科学和技术的历史做出贡献。这项研究的重点是促进对共轭聚合物结构-功能关系的理解，特别是给体-受体相互作用在制备减小的带隙（Eg=1.5- 2.0eV）和低带隙（Eg 1.5eV）聚合物的努力中的作用。 带隙是有机半导体材料的关键参数，特别是对于它们在电致变色器件、有机光致发光器件、有机发光二极管和NIR光电探测器中的应用。这里特别关注的是将常规受体单元与噻吩并[3，4-B]吡嗪结构单元配对的新设计范例的应用。 这些结构单元同时充当非常强的受体和非常强的供体。共辄聚合物的制备使用直接芳基化聚合完成。计算技术有助于实验设计，预测所需的电子特性。 这种新的设计范例被应用于其他单体，如苊并[1，2-B]噻吩并[3，4-e]吡嗪、二苯并[f，h]噻吩并[3，4-B]喹喔啉和噻吩并[3 '，4'：5，6]吡嗪并[2，3-f][1，10]菲咯啉，并且通过建立的合作在设备中测试了一些材料。 这项研究解决了涉及两个单独的受体共轭聚合物的基本设计原则。 该化学奖具有变革性，具有很强的潜力，可以促进对共轭聚合物设计的基本理解，特别是在低带隙、n型和双极性聚合物的设计方面。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

With this award, the Macromolecular, Supramolecular, and Nanochemistry Program in the Division of Chemistry is funding Professor Seth C. Rasmussen of the Department of Chemistry and Biochemistry at North Dakota State University to advance fundamental understanding of structure-function relationships in conjugated polymers. Conjugated polymers are long chain, organic molecules. Much like traditional semiconductors such as silicon, these polymers can become conductive when one applies a voltage (such as in transistors) or light (such as in solar cells). This team creates design strategies for constructing new types of conjugated polymers with potential applications in organic electronics, photovoltaics and organic light-emitting diodes. In addition to conventional synthetic techniques, computational modelling is used to evaluate potential polymer structures and to predict their electronic properties. The broader activities associated with this research focus on outreach to Native American colleges via the university’s NATURE program. The team also contributes to the history of polymer science and technology via the documentation and dissemination of new historical publications on the origin and growth of conjugated polymers.This research is focused on advancing understanding of structure-function relationships in conjugated polymers, in particular the role of donor-acceptor interactions in efforts to produce reduced band gap (Eg=1.5-2.0 eV) and low band gap (Eg1.5 eV) polymers. The band gap is a critical parameter of organic semiconducting materials, particularly for their application in electrochromic devices, organic photovoltaics, organic light-emitting diodes, and NIR photodetectors. Of particular focus here is the application of a new design paradigm that pairs conventional acceptor units with thieno[3,4-b]pyrazine building blocks. These building block act simultaneously as very strong acceptors and very strong donors. The preparation of the conjugated polymers is accomplished using direct arylation polymerizations. Computational techniques aid in experimental design, predicting desired electronic properties. This new design paradigm is applied to other monomers such as acenaphtho[1,2-b]thieno[3,4-e]pyrazine, dibenzo[f,h]thieno[3,4-b]quinoxaline and thieno[3',4':5,6]pyrazino[2,3-f][1,10]phenanthroline, and some of the materials are tested in devices via established collaborations. This research addresses the fundamental design principle for conjugated polymers involving two separate acceptors. The chemistry is transformative with a strong potential to advance fundamental understanding of conjugated polymer design, especially in terms of the design of low band gap, n-type, and ambipolar polymers.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.