Tuning the Carrier Scattering Mechanism by Rare-Earth Element Doping for High Average zT in Mg3Sb2-Based Compounds.
Tuning the Carrier Scattering Mechanism by Rare-Earth Element Doping for High Average zT in Mg3Sb2-Based Compounds.
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DOI：
10.1021/acsami.1c23395
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发表时间：
2022-01
影响因子：
9.5
通讯作者：
Ke Liu;Chen Chen-Chen;Xiaofang Li;Jucai Jia;C. Xia;J. Mao;Quan Huang;J. Sui;Feng Cao;
中科院分区：
文献类型：
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作者：
Ke Liu;Chen Chen-Chen;Xiaofang Li;Jucai Jia;C. Xia;J. Mao;Quan Huang;J. Sui;Feng Cao;
mg3sb2基化合物具有优异的热电性能、低廉的成本和良好的力学性能，是一种很有前途的热电材料。在本研究中，Er、Dy、Gd和Nd都被证实是有效的n型掺杂剂，可以优化mg3sb2基化合物的载流子浓度，增加态有效质量密度，抑制离子杂质散射。通过提高烧结温度，可以获得更大的晶粒尺寸，并且可以有效地提高整个测量温度范围内载流子的迁移率。结果表明，Mg3.07Er0.03Bi0.5Sb1.5、Mg3.07Dy0.03Bi0.5Sb1.5和Mg3.07Nd0.03Bi0.5Sb1.5在673 K时zT最大值大于~ 1.6，在300 ~ 673 K之间zT平均值大于~ 1.0。此外，Mg3.07Dy0.03Bi0.5Sb1.5的抗压强度高达~ 180 MPa。因此，稀土元素掺杂的mg3sb2基化合物在热电领域具有广阔的应用前景。
Mg3Sb2-based compounds are promising thermoelectric materials because of their excellent thermoelectric performance, low cost, and good mechanical properties. In this work, Er, Dy, Gd, and Nd are all confirmed to be effective n-type dopants for optimizing the carrier concentration, increasing the density of states effective mass, and suppressing the ionized impurity scattering of Mg3Sb2-based compounds. By increasing the sintering temperature, a larger grain size can be achieved and can effectively improve the carrier mobility in the whole measured temperature range. As a result, maximum zT values above ∼1.6 at 673 K and average zTs above ∼1.0 between 300 and 673 K were achieved for Mg3.07Er0.03Bi0.5Sb1.5, Mg3.07Dy0.03Bi0.5Sb1.5, and Mg3.07Nd0.03Bi0.5Sb1.5. In addition, a high compressive strength of ∼180 MPa was obtained in Mg3.07Dy0.03Bi0.5Sb1.5. Therefore, rare-earth element-doped Mg3Sb2-based compounds are promising for thermoelectric applications.