Thermoelectric Materials and Devices Laboratory, Department of Physics, Indian Institute of Science, Bangalore-560012, India.
J Phys Condens Matter. 2013 Mar 13;25(10):105701. doi: 10.1088/0953-8984/25/10/105701. Epub 2013 Feb 8.
Void filling in (I) Bi(x)-added Co(4)Sb(12) or (II) Sb/Bi substitution of Co(4)Sb(12-x)Bi(x) has been investigated for structural and thermoelectric properties evaluation. X-ray powder data Rietveld refinements combined with electron probe microanalyses showed a polycrystalline and practically Bi-free CoSb(3) skutterudite phase as the major constituent as well as a secondary Bi phase in the grain boundaries. For series I alloys, the electrical conductivity, Seebeck coefficient and thermal conductivity were measured as a function of temperature in the range from 450 to 750 K. The electrical conductivity of all the samples increased with increasing temperature, showing a semiconducting nature with smaller values of the Seebeck coefficient for higher Bi fractions. Conduction over the entire temperature range was found to arise from a single p-type carrier. Thermal conductivity showed a reduction with Bi added in all the samples, except for Bi(0.75)Co(4)Sb(12), and the lowest lattice thermal conductivity was found for a Bi-added fraction of 0.5. The maximum zT value of 0.53 at 632 K is higher than that of Co(4)Sb(12).
已研究了（I）Bi 掺杂的 Co(Sb)(4)或（II）Co(Sb)(4-x)Bi(x)中的 Sb/Bi 取代，以评估其结构和热电性能。X 射线粉末数据 Rietveld 精修与电子探针微分析相结合表明，多晶且实际上无 Bi 的 CoSb(3) skutterudite 相是主要成分，晶界处存在次要的 Bi 相。对于系列 I 合金，在 450 至 750 K 的温度范围内测量了电导率、塞贝克系数和热导率随温度的变化。所有样品的电导率随温度升高而增加，表现出较小的塞贝克系数的半导体性质，较高的 Bi 分数。在整个温度范围内的传导被发现是由单一的 p 型载流子引起的。除了 Bi(0.75)Co(4)Sb(12)外，所有样品中添加 Bi 都会降低热导率，而添加 Bi 的分数为 0.5 时晶格热导率最低。在 632 K 时，最大 zT 值为 0.53，高于 Co(Sb)(4)。
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