A10LaCdSb9 (A=Ca, Yb): a highly complex Zintl system and the thermoelectric properties.
A10LaCdSb9 (A=Ca, Yb): a highly complex Zintl system and the thermoelectric properties.
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DOI：
10.1002/asia.201200827
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
Jian Wang;S. Xia;X. Tao
中科院分区：
文献类型：
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作者：
Jian Wang;S. Xia;X. Tao
应用Zintl设计合成了两种新的Zintl化合物A(10)LaCdSb(9) (A=Ca, Yb)，即Ca(9.81(1))La(0.97(1))Cd(1.23(1))Sb(9)和Yb(9.78(1))La(0.97(1))Cd(1.24(1))Sb(9)。概念。虽然这两种化合物与其 Ca(11)InSb(9) 和 Yb(11)InSb(9) 类似物都是等电子的，但它们以正交空间群 Ibam (No.72) 的新结构类型结晶，并具有非常复杂的阴离子结构，由独特的 [Cd(2)Sb(6)](12-) 簇、哑铃形 [Sb(2)](4-) 二聚体和孤立的结构组成。 [Sb](3-) 阴离子。对于Yb(9.78(1))La(0.97(1))Cd(1.24(1))Sb(9)，在875 K时观察到极低的晶格热导率为0.29 W m(-1) K(-1)，这几乎接近非玻璃或非离子导电块体材料的最低报道极限。根据热重（TG）和差示扫描量热（DSC）分析，两种化合物都表现出非常好的热稳定性，并且在1173 K以下没有发现熔化或相变过程。尽管Yb(9.78(1))La(0.97(1))Cd(1.24(1))Sb(9)的相关热电性质研究仅在920 K时呈现出最大ZT为0.11，因为其塞贝克值较低系数，这些材料因其高温稳定性和低热导率仍然非常有前途。此外，由于混合阳离子具有不同的电荷，因此该系统在调整相关电性能方面非常灵活。
Two new Zintl compounds A(10)LaCdSb(9) (A=Ca, Yb), namely, Ca(9.81(1))La(0.97(1))Cd(1.23(1))Sb(9) and Yb(9.78(1))La(0.97(1))Cd(1.24(1))Sb(9), have been designed and synthesized by applying the Zintl concept. Although both compounds are isoelectronic with their Ca(11)InSb(9) and Yb(11)InSb(9) analogues, they crystallize in a new structure type with the orthorhombic space group Ibam (No.72) and feature very complex anion structures, which are composed of unique [Cd(2)Sb(6)](12-) clusters, dumbbell-shaped [Sb(2)](4-) dimers, and isolated [Sb](3-) anions. For Yb(9.78(1))La(0.97(1))Cd(1.24(1))Sb(9), an extremely low lattice thermal conductivity of 0.29 W m(-1) K(-1) was observed at 875 K, which almost approaches the lowest reported limit of nonglassy or nonionically conducting bulk materials. According to thermogravimetric (TG) and differential scanning calorimetry (DSC) analyses, both compounds show very good thermal stability and no melting or phase transition processes were found below 1173 K. Although related thermoelectric property studies on Yb(9.78(1))La(0.97(1))Cd(1.24(1))Sb(9) only present a maximum ZT of 0.11 at 920 K, owing to its low Seebeck coefficients, these materials are still very promising for their high temperature stability and low thermal conductivity. Furthermore, as mixed cations exist with different charges, it makes this system very flexible in tuning the related electrical properties.