Abstract Recently, Zintl phase Mg3Sb2 has displayed superior n-type thermoelectric properties. However, the corresponding p-type thermoelectric materials with high thermoelectric properties are still in urgent need. CaMg2Bi2-based Zintl compound attracts increasing enthusiasm in recent years due to its high carrier mobility and low lattice thermal conductivity. Here, Yb is used to replace Ca to further tune thermoelectric transport behavior of CaMg1.9Zn0.1Bi1.98, an optimized composition according to previous work. The synergistic effect of the enhanced carrier concentration caused by electronegativity difference in cation site and the suppressed lattice thermal conductivity induced by the stronger point defects scattering leads to the peak ZT of 1.0 in Ca0.65Yb0.35Mg1.9Zn0.1Bi1.98, which exceeds most of reported CaMg2Bi2-based materials. The maximum ZTeng of single p-type leg Ca0.65Yb0.35Mg1.9Zn0.1Bi1.98 is up to 0.54 between Tc = 300 K and Th = 773 K, catching up with the current highest level in 1-2-2 Bi-based materials. Moreover, the interrelationship between conversion efficiency and p-n pair cross-section area ratio (An/Ap) is considered. For n-type Mg3.1Co0.1Sb1.5Bi0.49Te0.01/p-type Ca0.65Yb0.35Mg1.9Zn0.1Bi1.98 pair, a maximum conversion efficiency of ~12% is obtained at the optimum An/Ap approaching to 1. This prominent conversion efficiency and equal cross-section area facilitate the module fabrication process and exhibit bright prospect of CaMg2Bi2-based thermoelectric materials.

中文翻译：

---

P型CaMg2Bi1.98的热电性能增强和等截面面积优化的CaAl2Si2型Zintl相模块

摘要 近年来，Zintl 相 Mg3Sb2 表现出优异的 n 型热电性能。然而，仍然迫切需要相应的具有高热电性能的p型热电材料。近年来，基于CaMg2Bi2 的Zintl 化合物由于其高载流子迁移率和低晶格热导率而受到越来越多的关注。在这里，Yb 用于代替 Ca 以进一步调整 CaMg1.9Zn0.1Bi1.98 的热电传输行为，这是根据先前工作优化的成分。由阳离子位点电负性差异引起的载流子浓度增强和更强点缺陷散射引起的晶格热导率抑制的协同作用导致 Ca0.65Yb0.35Mg1.9Zn0.1Bi1.98 的峰值 ZT 为 1.0，超过大多数报道的 CaMg2Bi2 基材料。单个p型腿Ca0.65Yb0.35Mg1.9Zn0.1Bi1.98的最大ZTeng在Tc = 300 K和Th = 773 K之间高达0.54，赶上了1-2-2 Bi-基于材料。此外，还考虑了转换效率和 pn 对横截面积比 (An/Ap) 之间的相互关系。对于 n 型 Mg3.1Co0.1Sb1.5Bi0.49Te0.01/p 型 Ca0.65Yb0.35Mg1.9Zn0.1Bi1.98 对，在最佳 An/Ap 接近于1. 这种突出的转换效率和相等的横截面积有利于模块的制造过程，并展现出 CaMg2Bi2 基热电材料的光明前景。考虑了转换效率和 pn 对横截面积比 (An/Ap) 之间的相互关系。对于 n 型 Mg3.1Co0.1Sb1.5Bi0.49Te0.01/p 型 Ca0.65Yb0.35Mg1.9Zn0.1Bi1.98 对，在最佳 An/Ap 接近于1. 这种突出的转换效率和相等的横截面积有利于模块的制造过程，并展现出 CaMg2Bi2 基热电材料的光明前景。考虑了转换效率和 pn 对横截面积比 (An/Ap) 之间的相互关系。对于 n 型 Mg3.1Co0.1Sb1.5Bi0.49Te0.01/p 型 Ca0.65Yb0.35Mg1.9Zn0.1Bi1.98 对，在最佳 An/Ap 接近于1. 这种突出的转换效率和相等的横截面积有利于模块的制造过程，并展现出 CaMg2Bi2 基热电材料的光明前景。