中文摘要：

通过水热法合成不同Se掺杂量的Bi2Te3-xSex（0≤x≤0.45）纳米粉体,采用放电等离子烧结技术,制备出致密度较高的块体材料。通过X射线衍射、扫描电镜、透射电镜等测试手段对材料的微结构进行了表征,并重点研究了含有不同Se掺杂量块体材料的显微结构和热电性能。结果表明：Se元素的掺杂使得粉体XRD特征衍射峰向高角度偏移,并且衍射峰出现宽化,晶粒尺寸变小。随着Se掺杂量的增加,块体材料的电导率先增大后减小;Se元素的掺杂有效地降低了材料的热导率,并提高了材料的Seebeck系数。研究结果表明：在整个测试温度区间,所有经过Se掺杂的样品ZT值都高于未掺杂样品。当Se掺杂量为0.3时,样品具有最大的ZT值,平均约为0.51,并在475 K时达到最大值0.57,相比未经Se掺杂的Bi2Te3提高了159%。

英文摘要：

A hydrothermal method combined with a subsequent spark plasma sintering technique was successfully utilized to synthesize selenium （Se） doped bismuth telluride （Bi2Te〉xSex） （0≤x≤0.45）. The influence of Se-doping on the composition and morphology of n-type Bi2Te3.xSex was studied by X-ray diffraction, scanning electron microscope and transmission electron microscope. Thermoelectric properties of the as-prepared bulk Bi2Te3.xSex nanocomposites were investigated in detail. Results showed that the grain became finer by the Se-doping. With in- creasing Se doping content, the electrical conductivity of bulk Bi2Te3.xSex increased firstly and then decreased. Se-doping effectively reduced the thermal conductivity and improved the Seebeck coefficient to some extent. Con- sequently, a maximum ZT value of 0.57 was obtained from bulk Bi2Te2.7Se0.3 at 475 K, which was increased by 159% as compared with pure bulk Bi2Te3.