报告题目： COMPLEX THERMOELECTRIC MATERIALS 复杂热电材料
时 间 ：2018年5月24日下午16:00
地 点 ：虎溪校区图书馆1F-9
邀 请 人 ：周小元 卢旭
报告摘要：
The widespread use of thermoelectric generators has been limited by the low material efficiency of the thermoelectric material. A number of strategies for Complex Thermoelectric Materials with higher Thermoelectric figure of merit, zT, are being actively studied. Complex electronic band structures provide mechanisms to achieve high zT in thermoelectric materials through band structure engineering. High zT is obtained p-type PbTe and PbSe which contains both light and heavy valence bands that can be engineered by alloying to achieve high valley degeneracy which leads to an extraordinary peak zT of about 2 at 750K . Complex crystal structures that enable relatively low thermal conductivity have lead to several new classes of thermoelectric materials. Ca3AlSb3, Ca5Al2Sb6 and Yb14AlSb11 are complex Zintl compounds containing differently connected AlSb4 tetrahedra that obtain zT near 1 at high temperatures. Fast diffusing or ‘liquid-like’ elements in the complex materials Zn4Sb3 and Cu2Se provide additional mechanisms to scatter and otherwise inhibit phonon heat conductivity. The principles of Zintl chemistry facilitates the search for new complex materials and the tuning of known thermoelectric materials with earth abundant, non-toxic elements。 Finally, the incorporation of nanometer sized microstructure reduces thermal conductivity from long mean-free-path phonons. This principle has been successfully demonstrated in (Bi,Sb)2Te3 alloys with arrays of dislocations at grain boundaries . The synthesis of nanoscale composites can be controlled with the aid of equilibrium phase diagrams (experimental or theoretically determined) to produce microstructure of varying composition and length scale .
报告人介绍：
杰弗里·施耐德(G. Jeffrey Snyder)教授于1991年获得康奈尔大学(Cornell University) 理学学士学位，随后他在德国斯图加特的马克斯·普朗克研究所(Max Planck institute FKF, festkorperrendschung)从事固态化学研究。他于1997年获得了斯坦福大学应用物理学博士学位，主要研究领域为金属钙钛矿的磁性和磁电传输特性。他作为高级研究员，在美国宇航局喷气推进实验室热研究组从事9年(1997-2006)研究工作。与此同时，他也兼任加州理工学院(Caltech，2006-2014) 材料科学系研究教授，专注于热电材料和设备的研发。2015年，他成为西北大学材料科学系终身教授。他在热电领域的贡献包括发现新的Zintl相热电材料和纳米热电复合材料以及能带结构工程优化热电性能。目前斯奈德教授发表了超过400篇文章、书章和专利，其中包括Nature, Science, Nature Materials 等顶级刊物。作为热电领域的最杰出的科学家之一，他曾担任国际热电协会的财务主管和副主席。
施耐德教授在快速发展的热电领域发表了一系列开创性工作，是SCI高被引用的科学家之一(Thomson Reuters 2016)。2008年，他在《自然材料》杂志上发表了一篇评论文章，不仅对热电领域的员工起到指导作用，并向多学科的研究者介绍了热电的要点。这是2013年热电学中被引用最多的一篇文章。
