Preparation and thermoelectric properties of Bi2Te2.7Se0.3 nanocomposites

Cu- or Ag-dispersed Bi2Te2.7Se0.3 nanocomposites were prepared by using metal-acetate decomposition and hot pressing. Cu or Ag nanoparticles were well-dispersed in the Bi2Te2.7Se0.3 matrix, and thereby the power factor was greatly increased due to the increase in the effective mass of a carrier. However, Cu or Ag dispersion did not affect the carrier concentration and could not reduce the lattice thermal conductivity because Cu or Ag nanoparticles did not act as phonon scattering centers effectively. The thermoelectric figure of merit was enhanced remarkably over a wide temperature range of 323-523 K due to the high power factor. Compared to Ag dispersion, Cu dispersion was much more effective in enhancing the thermoelectric performance.