CdI2 structure type as potential thermoelectric materials: Synthesis and high temperature thermoelectric properties of the solid solution TiSxSe2−x
CdI2 structure type as potential thermoelectric materials: Synthesis and high temperature thermoelectric properties of the solid solution TiSxSe2−x
复制标题
DOI：
10.1016/j.jallcom.2012.01.067
复制
发表时间：
2012-04
影响因子：
6.2
通讯作者：
F. Gascoin;N. Raghavendra;E. Guilmeau;Y. Bréard
中科院分区：
文献类型：
--
作者：
F. Gascoin;N. Raghavendra;E. Guilmeau;Y. Bréard
固溶体TiSxSe2− x（x从0到2变化）的多晶样品是使用化学计量量的元素的直接高温反应制备的。粉末X射线衍射数据的Rietveld精化与全固溶体的存在是一致的。对放电等离子烧结致密化的球团进行了高温塞贝克系数、电阻率和热扩散率的测量。这些测量结果表明，沿着固溶体的输运性质的变化，从相当金属和p型的TiSe 2的半导体和n型的TiS 2。这种导电制度的变化是负责的特殊的演变的运输性能的TiS0.5Se1.5随着温度的升高，变化有点不同，比其他成员的固溶体。正如预期的那样，由S和Se在阴离子位点上的混合占据所产生的无序是导致晶格热导率减小的原因。对于TiS1.5Se0.5，在400°C下达到高于0.4的最大zT。
Polycrystalline samples of the solid solution TiSxSe2−xwith x varying from 0 to 2 were prepared using direct high temperature reaction of stoichiometric amounts of the elements. Rietveld refinements of powder X-ray diffraction data are consistent with the existence of a full solid solution. High temperature Seebeck coefficient, electrical resistivity and thermal diffusivity measurements were performed on pellets densified by spark plasma sintering. These measurements reveal that along the solid solution the transport properties vary from the rather metallic and p-type character of TiSe2to the semiconducting and n-type of TiS2. This change of conduction regime is responsible for the peculiar evolutions of transport properties of TiS0.5Se1.5with increasing temperature that vary somewhat differently than that of the other members of the solid solution. As expected, the disorder generated by the mixed occupancy of the S and Se on the anionic site is responsible for the diminution of the lattice thermal conductivity. A maximum zT above 0.4 at 400°C is reached for TiS1.5Se0.5.