开发高性能PbTe基热电材料是热电学界研究的核心内容之一。PbTe属于面心立方结构，其熔点高、禁带宽度大，适用于中温区热电发电领域。目前热电研究主要集中在金属掺杂PbTe多晶体系，然而由于晶界、缺陷等非本征因素的影响，严重阻碍了对其各向同性和电声输运特性的理解。因此，亟需开发大尺寸PbTe基单晶的宏量制备技术，这是实现商业化应用的关键因素。本项目拟通过Pb位掺杂不同金属元素，利用垂直Bridgman法合成MxPb1-xTe(M=Sn,Mn,Ga,Ag等)系列单晶，调控和优化载流子浓度及能带结构，并结合理论与实验结果，研究金属掺杂前后PbTe单晶各向同性和各向异性的本质机理，获取不同取向上电声输运的基本物理参数，揭示金属原子与Pb、Te原子的相互作用关系、以及主导载流子与声子散射的内在机制，建立微结构、电声输运机制、各向异性与热电性能之间的关联，为设计和开发高效热电材料提供新思路。

One of core contents is to develop high-performance PbTe-based thermoelectric materials in thermoelectric research community. As for PbTe system, it has face-centered cubic structure with high melting point and large band gap. So far, thermoelectric studies are mainly focused on metal-doped PbTe polycrystal system. However, considering the unessential factors such as grain boundary, defects, etc., it seriously hinders the understanding of intrinsic characteristics of isotropy and electron and phonon transport. Therefore, it is urgent to develop the Macro fabrication technique of large-sized PbTe single crystals, which is the key factor for commercial applications. In this project, we will utilize the vertical Bridgeman method to fabricate a series of MxPb1-xTe (M=Sn, Mn, Ga, Ag, etc.) single crystals by different metal doping at Pb sites. Furthermore, we will modulate and optimize carrier concentration and band structure. Combined with theoretical and experimental results, we will study the essential mechanism of isotropy and anisotropy of metal-doped PbTe single crystals, and obtain the basic physical parameters of electron and phonon transport along different measured orientations. All of results will reveal the interaction among doped metal, Pb, and Te atoms, and intrinsic mechanism between dominant carrier and phonon scattering. Ultimately, we will establish the association among microstructure, electron-phonon transport mechanism, anisotropy, and thermoelectric performance, which provides new idea for the design and development of high efficient thermoelectric materials.