Saito Wataru, Hayashi Kei, Huang Zhicheng, Dong Jinfeng, Li Jing-Feng, Miyazaki Yuzuru
Department of Applied Physics, Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan.
State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China.
ACS Appl Mater Interfaces. 2020 Dec 30;12(52):57888-57897. doi: 10.1021/acsami.0c17462. Epub 2020 Dec 15.
MgSn is a potential thermoelectric (TE) material that exhibits environmental compatibility. In this study, we fabricated Sb-doped MgSn (MgSnSb) single-crystal ingots and demonstrated the enhancement of TE performance via point defect engineering and Sb doping. The MgSnSb single-crystal ingots exhibited considerably enhanced electrical conductivity because of the donor-doping effect in addition to high carrier mobility. Moreover, the MgSnSb single-crystal ingots contained Mg vacancy (V) as a point defect. The introduced V and doped Sb atoms formed nanostructures, both acting as phonon-scattering centers. Consequently, lower lattice thermal conductivity was achieved for the MgSnSb single-crystal ingots compared with polycrystalline counterparts. Owing to the significant enhancement in the electrical conductivity and the reduction in the lattice thermal conductivity, the maximum power factor of 5.1(4) × 10 W/(K m) and the maximum dimensionless figure of merit of 0.72(5) were achieved for the MgSnSb single-crystal ingot, which are higher than those of single-phase MgSnSb polycrystals.
MgSn是一种具有环境兼容性的潜在热电（TE）材料。在本研究中，我们制备了Sb掺杂的MgSn（MgSnSb）单晶锭，并通过点缺陷工程和Sb掺杂证明了热电性能的增强。由于施主掺杂效应以及高载流子迁移率，MgSnSb单晶锭表现出显著增强的电导率。此外，MgSnSb单晶锭包含Mg空位（V）作为点缺陷。引入的V和掺杂的Sb原子形成了纳米结构，二者均充当声子散射中心。因此，与多晶相比，MgSnSb单晶锭的晶格热导率更低。由于电导率的显著提高和晶格热导率的降低，MgSnSb单晶锭实现了5.1(4)×10 W/(K²m²)的最大功率因子和0.72(5)的最大无量纲品质因数，高于单相MgSnSb多晶。
