Cu-dispersed Bi2Te2.7Se0.3 nanocomposites were prepared by Cu(OAc)2 acetate decomposition and their thermoelectric properties were evaluated. The electrical conductivity did not change significantly by the Cu nanoparticle dispersion because the doping effect by Cu nanoparticles did not occur effectively to increase the carrier concentration and Cu nanoparticles were too small to introduce charge carrier scattering. All specimens had a negative Seebeck coefficient, which confirmed that the electrical charge was transported mainly by electrons. The absolute Seebeck coefficient was remarkably increased by the Cu dispersion and slightly reduced with an increase in the temperature. The power factor values for Cu-dispersed Bi2Te2.7Se0.3 were maintained higher in the whole temperature range, and the maximum power factor at 323 K reached around two times higher than that of Bi2Te2.7Se0.3. The thermal conductivity of Cu-dispersed Bi2Te2.7Se0.3 was slightly increased with an increase in the temperature because of the electronic contribution, and the Cu dispersion could not reduce it. The thermoelectric figure of merit was enhanced remarkably over a wide temperature range of 323~523 K due to the high power factor and the maintenance of a low thermal conductivity.

Keywords: Thermoelectric, Bismuth telluride, Dispersion.