Preparation and thermoelectric properties of n-type Bi2Te3-xSex nanostructured materials
The bulk of Bi,Te and Se were prepared into nanopowder by evaporation condensation method,and the Bi2Te3-xSexalloy powder was obtained after mechanical alloying of the nanopowder.The alloy powder was sintered using microwave sintering technology to obtain a nanostructured bulk material,and its microstructure and thermoe-lectric properties were characterized and analyzed.The sintered samples are composed of a single phase.The materi-als have a layered microstructure and the nanostructures composed of large number of fine grains with grain sizes of 50-100 nm.With the increase of Se content,the electrical transport characteristics of sintered samples change from semiconductors to metals,and the formation of nanostructures effectively reduces thermal conductivity,which is conducive to the improvement of thermoelectric properties.When the Se content x=0.20,the Bi2Te2.80 Se0.20 sample achieves a maximum ZT value of 0.85 near 423K.
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