采用溶剂热合成再热处理方法制备了Ag_xCo_4Sb_(12)(x=0,0.1,0.2)粉末,粉末经真空熔融处理得到块体试样.用X射线衍射和扫描电镜分别分析了样品的物相和断面显微结构.测试了试样从室温至773K的电导率和Seebeck系数.Ag掺杂的试样Seebeck系数均是正的,呈p-型导电,而未掺杂的试样在T～325K时从n-型转变为p-型.Ag的引入使CoSb_3的电导率显著提高,在整个测试范围内其功率因子均比CoSb_3的高.而x=0.2的试样其电导率和热电功率因子较其它试样都高,在299K时电导率达到4516S·cm~(-1),573K时功率因子达到12.3×10~(-6)W·K~(-2)·cm~(-1).分析认为Ag是以替代Co的形式进入CoSb_3晶格,而并非如预计的那样进入CoSb_3的结构孔洞.
Ag_xCo_4Sb_(12)(x=0, 0.1, 0.2) bulk materials have been prepared by combining solvothermal synthesis and vacuum melting method. The phase structures, compositions, and microstructures of the materials were characterized by XRD and SEM,respectively. The electrical conductivity and Seebeck coefficient of the samples were measured in the temperature range of 300～ 773K. The Ag doped samples show p-type conduction in all the temperature range measured, whereas the undoped sample changes from n-type to p-type at ～325K. The addition of Ag obviously increases electrical conductivity and power factor in the temperature range measured. The maximum electrical conductivity and power factor of the Ag_(0.2)Co_4 Sb_(12) sample are 4516S·cm~(-1) at 299K and 12.3×10~(-6)W·K~(-2)· cm~(-1) at 573K respectively. It is considered that Ag atoms are at Cosites rather than at the voids of the crystal structure, which is beyond our expectation.
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