Understanding Thermal Transport Properties in Electrically Conductive Polymers

导电性聚合物彻底改变了现代设备，使塑料太阳能电池、电子产品和热电设备取得了进步。这些设备的性能与热量如何通过传导消散或如何通过绝缘捕获热量有关。本项目旨在研究导电聚合物中的热输运性质如何受到载流子和聚合物主链结构的影响。通过增强我们对聚合物热传输的基本理解，该项目将为设计高效聚合物基器件提供有价值的新知识和新的实用策略。通过为代表性不足的少数族裔社区提供研究机会，促进可再生能源领域的多样性，该项目还将通过可再生热能收集项目教育K-12和本科生，培养下一代能源技术工程师和科学家。了解聚合物中的热输运物理一直是一个长期的挑战。现有的理论和模拟不能定量地描述聚合物中导热性的增强（或降低）。该项目的总体目标是阐明载流子（极化子和双极化子）和结构参数（短程位置顺序、取向顺序和链构象）如何定量地影响沿着（和跨）链方向的导热性，这是在提供导电聚合物热传导的微观图像中缺失的部分。该项目将通过最先进的技术，包括瞬态频域热反射，研究温度相关的导热系数、热容、电导率和塞贝克系数。为了预测热导率，将通过电化学掺杂工程设计和合成具有精确控制掺杂水平、调节载流子密度和定制链结构的噻吩基共轭聚合物。该项目不仅将深入了解导电聚合物的热传输过程，还将为开发基于微观能量载流子相互作用的新型电子设备提供变革性机会。作为一种典型的聚合物，聚（3-烷基噻吩）共轭聚合物广泛应用于场效应晶体管和太阳能电池等有机电子产品中，其热导率可控，将为提高效率提供独特的机会。这项工作的更广泛的技术影响包括更好的热管理应用的新策略，如没有过热问题的有机发光二极管（oled）。该教育计划将促进工程劳动力中所有群体的多样性和包容性，包括女性和来自未被充分代表的种族和族裔群体的个人。该奖项反映了美国国家科学基金会的法定使命，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。

Electrically conductive polymers have revolutionized modern devices, enabling advancements in plastic solar cells, electronics, and thermoelectric devices. The performance of these devices is linked to how heat is dissipated through conduction or how heat is trapped through insulation. This project aims to investigate how thermal transport properties in electrically conductive polymers are affected by charge carriers and polymer backbone structures. By enhancing our fundamental understanding of thermal transport in polymers, this project will provide valuable new knowledge and new practical strategies to design high-efficiency polymer-based devices. By providing research opportunities to underrepresented minority communities and promoting the diversity of the renewable energy field, this project will also educate K-12 and undergraduate students with hands-on renewable thermal energy harvesting projects, creating the next generation of engineers and scientists in energy technologies.Understanding thermal transport physics in polymers has been a long-standing challenge. Existing theories and simulations do not quantitatively describe thermal conductivity enhancement (or reduction) in polymers. The overarching goal of this project is to elucidate how charge carriers (polarons and bipolarons) and structural parameters (short-range positional orders, orientational orders, and chain conformations) quantitively affect thermal conductivities along (and across) chain directions, which are the missing pieces in providing a microscopic picture of heat conduction in electrically conductive polymers. This project will study temperature-dependent thermal conductivities, heat capacities, electrical conductivities, and Seebeck coefficients through state-of-the-art techniques including a transient frequency-domain thermoreflectance. To tune the thermal conductivities predictively, thiophene-based conjugated polymers with precisely controlled doping levels, tuned charge carrier densities, and tailored chain structures will be designed and synthesized by electrochemical doping engineering. This project will not only create insights into thermal transport processes in electrically conductive polymers, but also provide transformative opportunities to develop novel electronic devices based on the interaction of microscopic energy carriers. As a model polymer, poly(3-alkylthiophene) conjugated polymer that is widely used for organic electronics, including field-effect transistors and solar cells, with controllable thermal conductivity will offer unique opportunities for improved efficiency. The broader technical impacts of this work include new strategies for better thermal management applications such as organic light-emitting diodes (OLEDs) without overheating issues. The education plan will promote diversity and inclusion of all groups in engineering workforce, including women and individuals from underrepresented racial and ethnic groups.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.