Thermoelectric Properties of Doped Organic Semiconductors

非技术总和在美国，燃烧化石燃料发电所产生的大部分能源被浪费为热量。材料可以通过热电效应将温差转换为电压。这可以用在帮助捕获废热的设备中。目前最有效的热电材料是由稀有元素制成的。由丰富的碳制成的先进塑料也可以定制为导电，还具有热电效应。该项目由NSF材料研究部的固态和材料化学计划资助，开发了通过控制塑料的导电性和温差产生的电压来了解和优化塑料热电性能的方法。研究人员创造了新的材料，可以用来捕捉废热，或者与普通的电子设备集成，从环境中收集能量。这项研究是由研究生进行的，他们获得了分析塑料性能和如何开发新材料的技能。该培训为多学科科学领域的研究生研究人员做好准备，为未来在美国工作的职业生涯做准备。这些学生还通过在当地公立学校开展外联活动，帮助不同群体参与到研究的益处中来。更广泛的公众通过与专注于儿童科学和工程设计项目的项目建立合作伙伴关系。TECHNICAL SUMMARY有机热电材料提供了开发控制电能和热能转换的新方法的机会。该项目由美国国家科学基金会材料研究部的固态和材料化学计划资助，目前正在研究通过加工、理论和开发新的电掺杂方法来控制半导体聚合物热电性能的新方法。由于半导体聚合物的性能强烈依赖于加工方法，因此研究了允许半导体聚合物固定形态的电掺杂方法，以提供对无序材料中的热电势的洞察。利用热电势和电导率随温度变化的测量，研究了确定掺杂后电子态密度变化的模型。研究了结晶度和电导率之间的相互作用，以确定掺杂后电子结构的演变。还研究了本体聚合物的性质以及利用固态化学活化的可控掺杂方法。使用先进的同步辐射X射线散射技术和光谱方法研究了材料的微结构。研究了电掺杂对导热系数的影响，以确定改善导电性的加工方法是否也增加了导热系数。这项研究是由研究生进行的，他们获得了分析塑料性能和如何开发新材料的技能。该培训为多学科科学领域的研究生研究人员做好准备，为未来在美国工作的职业生涯做准备。这些学生还通过在当地公立学校开展外联活动，帮助不同群体参与到研究的益处中来。更广泛的公众通过与专注于儿童科学和工程设计项目的项目建立合作伙伴关系。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

NON-TECHNICAL SUMMARYMuch of the energy from burning fossil fuels to generate electricity in the U.S. is wasted as heat. Materials can convert a difference in temperature into an electrical voltage through the thermoelectric effect. This can be used in devices that help capture wasted heat. The most efficient thermoelectric materials are currently made from rare elements. Advanced plastics made from abundant carbon can also be tailored to conduct electricity and also have a thermoelectric effect. This project, funded by the Solid State and Materials Chemistry program in the Division of Materials Research at NSF, develops methods to understand and optimize the thermoelectric properties of plastics by controlling their electrical conductivity and the voltage generated by differences in temperature. The researchers create new materials that could be used to capture waste heat or integrated with common electronic devices for energy harvesting from the environment. This research is carried out by graduate students who gain skills in analyzing the properties of plastics and how to develop new materials. The training prepares graduate student researchers in multidisciplinary science for future careers in the U.S. workforce. These students also help to engage a diverse population in the benefits of research through outreach activities in local public schools. The broader public is engaged through partnerships with programs focused on science and engineering design projects for children.TECHNICAL SUMMARYOrganic thermoelectric materials present an opportunity to develop new means of controlling the conversion of electrical and thermal energy. New methods to control the thermoelectric properties of semiconducting polymers through processing, theory, and development of new electrical doping methods are being investigated in the project, which is funded by the Solid State and Materials Chemistry program in the Division of Materials Research at NSF. Because the properties of semiconducting polymers are strongly dependent on processing methods, electrical doping methods that allow fixed morphologies of semiconducting polymers are studied to provide insight into the thermopower in disordered materials. Models for determining the changes in the electronic density of states upon doping are investigated using temperature-dependent measurements of thermopower and electrical conductivity. The interplay between crystallinity and electrical conductivity is studied to determine the evolution of the electronic structure upon doping. The properties of bulk polymers and controlled methods for doping them that leverage chemical activation in the solid state are also investigated. The resulting microstructures of materials are studied using advanced synchrotron X-ray scattering techniques and by spectroscopic methods. The impact on thermal conductivity by electrical doping is examined to determine if processing methods that improve electrical conductivity also increase the thermal conductivity. This research is carried out by graduate students who gain skills in analyzing the properties of plastics and how to develop new materials. The training prepares graduate student researchers in multidisciplinary science for future careers in the U.S. workforce. These students also help to engage a diverse population in the benefits of research through outreach activities in local public schools. The broader public is engaged through partnerships with programs focused on science and engineering design projects for children.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.