Investigation of Zintl Compounds for Thermoelectric and Magnetic Applications

技术摘要：由热电材料制成的器件是环境友好的电源，为当今的能源问题提供了重要的解决方案。这些设备将热能直接转换为电能，几乎不需要燃料，维护最少，并且可以分段在很大的温度范围(300 1275K)下运行。Zintl相满足热电材料的许多要求。导致最佳热电器件的特性是高Seebeck系数、低电阻率和低热导率。该项目将确定可能是良好热电材料的材料，这些材料是带隙较小的半导体化合物，可以通过掺杂来增强或降低导电性，并且包含较大的单位电池、结构复杂和存在重元素。含Sb和Bi等重主族元素的锌化合物满足所有这些要求。这项提议强调从目前的范例开始寻找具有高品质因数的材料，这些材料将与现有材料兼容，用于能够在大温度梯度下工作的设备。该项目的重点是寻找新材料。它邀请研究生和本科生以及高中教师和学生对新材料进行探索性研究。他们学习合成设计，并参与使用最先进的技术进行表征。非技术摘要：热电设备是环境友好型电源，通过将热能直接转换为电能，提供一种解决能源需求的方案。这些设备几乎不需要燃料，维护最少，并且可以在很大的温度范围(300 1275K)下工作。这是一个研究领域，在这个领域，新材料具有降低成本和提高效率的潜力。锌化合物代表了一类很大程度上未被探索的相，具有良好热电性能所需的许多特性。这些化合物是具有大型复杂结构的半导体，可以很容易地进行掺杂和修饰，以优化所需的性能。这个多学科项目培训博士后、研究生和本科生新化合物的合成和表征。在面向高中生和教师的能源相关项目的研究机会方面，与社区的接触鼓励了未来的科学家，并增加了正在进行科学研究的人数。

Technical Abstract:Devices made from thermoelectric materials are environmentally benign power sources that provide a significant solution to todays energy problems. These devices convert thermal energy directly into electrical energy, require little-to-no fuel, minimal maintenance and can be segmented to operate over a large temperature range (300 1275 K). Zintl phases meet many of the requirements for thermoelectric materials. The properties that lead to optimal thermoelectric devices are high Seebeck coefficient, low electrical resistivity and low thermal conductivity. This project will identify materials as possible good thermoelectric materials which are are small band-gap, semiconducting compounds that can be doped to enhance or to reduce the conductivity, as well as containing large unit cells, structural complexity, and the presence of heavy elements. Zintl compounds containing heavy main group elements such as Sb and Bi meet all of these requirements. This proposal emphasizes the current paradigm as a starting place to look for materials with a high figure-of-merit that will be compatible with existing materials for a device that will be able to operate under large temperature gradients. The project focuses on a search for new materials. It engages graduate students and undergraduates as well as high school teachers and students in exploratory research on new materials. They learn about synthetic design and are involved in using state of the art techniques in characterization.Non-Technical Abstract:Thermoelectric devices are environmentally benign power sources that provide one solution to energy requirements through the direct conversion of heat into electrical energy. These devices require little-to-no fuel, minimal maintenance, and can operate over a large temperature range (300 1275 K). This is an area of research where new materials have the potential for reducing cost while increasing efficiency. Zintl compounds represent a class of largely unexplored phases with many of the desired characteristics for good thermoelectric properties. These compounds are semiconductors with large, complex structures that can be easily doped and modified to optimize desired properties. This multidisciplinary project trains postdoctoral, graduate and undergraduate students in the synthesis and characterization of new compounds. Outreach to the community in terms of research opportunities in energy related projects for high school students and teachers encourages future scientists and increases the number in the science pipeline.