Understanding Thermal Transport Properties in Electrically Conductive Polymers

导电聚合物已经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的进步成为可能。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传输特性如何受到电荷载体和聚合物主链结构的影响。通过提高我们对聚合物热传输的基本理解，该项目将提供有价值的新知识和新的实用策略，以设计高效的聚合物基器件。通过为代表性不足的少数民族社区提供研究机会，促进可再生能源领域的多样性，该项目还将通过实践可再生热能收集项目教育K-12和本科生，培养能源技术领域的下一代工程师和科学家。了解聚合物中的热传输物理一直是一项长期挑战。现有的理论和模拟没有定量地描述聚合物中热导率的增强（或降低）。这个项目的首要目标是阐明电荷载流子（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）链方向的热导率，这是在提供导电聚合物中的热传导的微观图像中缺失的部分。该项目将通过包括瞬态频域热反射在内的最先进的技术来研究温度相关的热导率、热容、电导率和塞贝克系数。为了预测性地调整热导率，将通过电化学掺杂工程设计和合成具有精确控制的掺杂水平、调整的电荷载流子密度和定制的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中的热传输过程，还将为开发基于微观能量载体相互作用的新型电子设备提供变革性机会。聚（3-烷基噻吩）共轭聚合物作为一种模型聚合物，具有可控的热导率，广泛用于有机电子器件，包括场效应晶体管和太阳能电池，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，如有机发光二极管（OLED），而不会出现过热问题。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，包括妇女和来自代表性不足的种族和族裔群体的个人。该奖项反映了NSF的法定使命，并通过使用基金会的智力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.