A series of thermoelectric nanocomposite samples were prepared by integrating Bi2Se3 nanoparticles into a bulk Bi 2Te3 matrix. Primarily, spherical Bi2Se 3 nanoparticles with diameter of ∼30 nm were synthesized by combining bismuth acetate with elemental Te in oleic acid solution. Bi2Te3-based nanocomposite samples were prepared by consolidating the appropriate quantity of Bi2Se3 nanoparticles with the starting elements (Bi and Te) using typical solid-state synthetic reactions. The microstructure and composition of the Bi2Te3-based nanocomposites, as well as the effects of the Bi2Se3 nanoparticles on their thermoelectric properties, are investigated. Transmission electron microscopy observation of the Bi2Te3-based nanocomposites reveals two types of interface between the constituent materials, i.e., coherent and incoherent, depending on the Bi 2Se3 concentration. The Bi2Se3 nanoparticles in the Bi2Te3 matrix act as scattering centers for a wider range of phonon frequencies, thereby reducing the thermal conductivity. As a result, the maximum ZT value of 0.75 is obtained for the Bi2Te3 nanocomposite with 10 wt.% Bi2Se3 nanoparticles at room temperature. It is clear that the reduction in the thermal conductivity plays a central role in the enhancement of the ZT value.
Bibliographical noteFunding Information:
This work was supported by the Basic Science Research Program through the National Research Foundation of Korea (20110003767), Nano Material Technology Development Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science, and Technology (20110030147), and ‘‘Center for Nano-structured Materials Technology’’ under ‘‘21st Century Frontier R&D Programs’’ of the Ministry of Education, Science, and Technology, Korea (2011K000197). Prof. Yo acknowledges financial support from the KISTI ReSEAT Program, Korea.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering
- Materials Chemistry