Thermoelectric properties of hydrothermally synthesized and hot pressed n-type Bi2Te3 alloys with different contents of Te

Nanosized Bi2Te3 based powders with the designed compositions of Bi2Tex (x = 2.85, 3.00, 3.15, 3.30, 3.45) have been synthesized by hydrothermal method. Bulk thermoelectric materials with crystal sizes smaller than 200 nm have been obtained by hot pressing of the hydrothermally synthesized Bi2Te3 based powders. It was found that all samples are n-type. A maximum power factor of 2.35 × 10−3 W m−1 K−2 was obtained at 312 K in the sample with a nominal composition of Bi2Te3.30.