Preparation and Thermoelectric Properties of SnSe1+x Bulk Samples by HEBM+SPS Methods

Thermoelectric materials can directly achieve heat conversion to electricity or electricity to heat, and the conversion efficiency can be determined by the temperature ratio between the cold and hot ends and the dimensionless thermoelectric figure of merit ZT value. SnSe-based thermoelectric materials have the highest ZT value in medium-high temperatures. The method of preparing the materials includes preparing the powder by mechanical alloying (MA) and then preparing the tin selenide block by high energy ball milling (HEBM) and the spark plasma sintering (SPS) methods. It is convenient for us to introduce impurities or vacancies in SnSe-based thermoelectric materials by this preparation method. Moreover, the crystalline grain of tin selenide is homogeneous and the materials are compact by this preparation method. We have prepared p-type semiconductor materials such as SnSe[Formula: see text] ([Formula: see text]) by introducing vacancies trying to improve the conductivity of the materials, and optimize the Seebeck coefficient of materials, to improve the thermoelectric figure of merit. In this work, the highest ZT values were obtained in the SnSe[Formula: see text] sample (ZT is about 0.69 at 750[Formula: see text]K).