Syntheses and thermoelectric properties of Bi2Te3∕Sb2Te3 bulk nanocomposites with laminated nanostructure

Abstract

Nanocomposites with constituent sizes of $<50\mathrm{nm}$ are considered as a promising approach to enhance the figure of merit of bulk thermoelectric materials. A simple route involving hydrothermal synthesis and hot pressing was used in this work to prepare ${\mathrm{Bi}}_2{\mathrm{Te}}_3∕{\mathrm{Sb}}_2{\mathrm{Te}}_3$ bulk nanocomposites. It is shown that the composites have a laminated structure composed of ${\mathrm{Bi}}_2{\mathrm{Te}}_3$ and ${\mathrm{Sb}}_2{\mathrm{Te}}_3$ nanolayers with the thickness varying alternately between 5 and $50\mathrm{nm}$ . The transport measurements indicate that the nanoscale laminated structure improves the thermoelectric performance with the maximal dimensionless figure of merit of 1.47 for the nanocomposite hot pressed from ${\mathrm{Bi}}_2{\mathrm{Te}}_3$ and ${\mathrm{Sb}}_2{\mathrm{Te}}_3$ nanopowders.