Bi_2Te_3/Bi_2Se_3纳米复合热电材料的制备和性能(英文)

Preparation and Properties of Bi_2Te_3/Bi_2Se_3 Thermoelectric Nanocomposite Materials

通过水热法分别合成了Bi2Te3和Bi2Se3纳米粉末,粉末按目标产物Bi2Te2.85Se0.15混合后真空热压烧结(523～623K,50或80MPa)制成块体材料。用X射线衍射(XRD)、扫描电镜(SEM)和场发射扫描电镜对合成的粉末和块体进行了分析,对块体在室温附近的载流子浓度、迁移率、霍尔系数、以及298～598K温度区间的电导率和Seebeck系数进行了测试。在623K,80MPa,保温60min真空热压烧结得到的样品的功率因子在298K达到了峰值19.1μWcm-1K-2。探讨了烧结温度和压力对材料相结构和形貌的影响。

Bi2Te3 and Bi2Se3 nanopowders were prepared by hydrothermal synthesis method.After having been mixed the Bi2Te3 and Bi2Se3 nanopowders were hot pressed at 523 to 623K and 50 or 80MPa in vacuum.The phase structure,morphology,and composition of the nanopowders and the hot pressed samples were examined by powder X-ray diffractometry,scanning electron microscopy,field emission scanning electron microscopy and energy dispersive spectroscopy,respectively.The carrier concentration,mobility,and Hall coefficient of the bulk samples were measured at room temperature.The electrical conductivity and Seebeck coefficient of the bulk samples were measured from room temperature up to 598K.The sample hot pressed at 623K and 80MPa for 60min reaches its maximum power factor -19.1μWcm-1 K-2 at -398K.And the influence of sintering temperature and pressure on the phase structure and morphology of the samples was studied.