FRG: Novel Approaches to the Search for Advanced Thermoelectric Materials

这个合作的重点研究小组（FRG）项目的目标是发明一种新的热电（TE）材料，将显着提高冷却和电力应用的效率。基于固体中的电子和热传输理论，半导体TE材料的理论模型已经存在了几十年。然而，没有已知的材料具有所有需要的电子和热特性。这项合作的目的是设计、合成和表征新型半导体热电材料，这些材料作为器件材料具有高效率。电子结构理论将为寻找这种材料提供一般性的指导。主要障碍是科学家无法预测新化合物的组成或结构，除非它们与已知化合物在化学上相似。然而，一旦发现新材料并确定其晶体结构，就可以计算其电子能带结构以及输运性质。因此，本研究具有很强的理论和实验成分。化学家，物理学家和理论家与他们的学生通过季度会议，互访和互联网通信之间的密切互动，将提供快速反馈和下一个实验和计算的规划。这个跨学科项目的教育和研究部分得到了很好的整合，通过特殊的协同作用，这个复杂项目的整体成功将得以实现。热电（TE）材料允许构造小型纯电子设备，这些设备在通过电流时提供热冷却，或者直接从热量产生电力。TE冷却器消除了对压缩机和气体（如氟利昂）的需求。然而，目前的TE冷却器效率较低（仅为最大允许值的10%，而家用冰箱的卡诺效率约为30%）。然而，这些器件用于效率不如小尺寸或可靠性重要的应用中。如果效率能提高到30%或更高，它们的使用将大大扩大，从而改善环境和经济效益。这是一个理想的训练基地，为学生。这个实验和理论项目是高度互动和跨学科的，参与的化学家和物理学家及其研究生和博士后学生之间表现出强大的协同作用。

The objective of this collaborative Focused Research Group (FRG) project is to invent a new class of thermoelectric (TE) materials that will significantly enhance the efficiency of cooling and power applications. Based on the theory of electronic and heat transport in solids, a theoretical model of semiconducting TE materials has been available for several decades. However, no known material has all the needed electronic and thermal characteristics. The purpose of this collaboration is to design, synthesize and characterize new classes of semiconducting thermoelectric materials that exhibit high efficiency as device materials. Electronic structure theory will provide general guidelines in the search for such materials. The main impediment is the inability of scientists to predict the composition or structure of new compounds, unless they are chemically similar to known compounds. However, once a new material is found and its crystal structure determined, its electronic band structure as well as transport properties can be calculated. Thus this research has both strong theoretical and experimental components. A close interaction between the chemists, physicists and theorists and their students through quarterly meetings, exchange visits, and internet communication, will provide rapid feedback and planning of the next experiments and calculations. The education and research components of this interdisciplinary project are well integrated, and overall success in this complex project will be realized through exceptional synergy.%%%Thermoelectric (TE) materials allow the construction of small, purely electronic devices that provide thermal cooling on passing a current, or that produce electricity directly from heat. TE coolers eliminate the need for compressors and gasses, such as freons. However, current TE coolers have low efficiency (only 10 % of the maximum allowed, while home refrigerators operate at about 30 % of Carnot efficiency.). Yet these devices are used in applications where efficiency is less important than small size or reliability. Their use would greatly expand if the efficiency could be raised to 30 % or more, resulting in environmental improvements and economic benefits. This is an ideal training ground for students. This experimental and theoretical project is highly interactive and interdisciplinary with strong synergy exhibited among the participating chemists and physicists and their graduate and postdoctoral students.