Fabrication Process and Thermoelectric Properties of CNT/Bi2(Se,Te)3 Composites

Carbon nanotube/bismuth-selenium-tellurium composites were fabricated by consolidating CNT/Bi-2(Se,Te)(3) composite powders prepared from a polyol-reduction process. The synthesized composite powders exhibit CNTs homogeneously dispersed among Bi-2(Se,Te)(3) matrix nanopowders of 300 nm in size. The powders were densified into a CNT/Bi-2(Se,Te)(3) composite in which CNTs were randomly dispersed in the matrix through spark plasma sintering process. The effect of an addition of Se on the dimensionless figure-of-merit (ZT) of the composite was clearly shown in 3 vol.% CNT/Bi-2(Se,Te)(3) composite as compared to CNT/Bi2Te3 composite throughout the temperature range of 298 to 473 K. These results imply that matrix modifications such as an addition of Se as well as the incorporation of CNTs into bismuth telluride thermoelectric materials is a promising means of achieving synergistic enhancement of the thermoelectric performance levels of these materials.