Enhancement of the Thermoelectric Power Factor for Bismuth Antimony Telluride Based Composites Containing Single-Walled Carbon Nanohorns

Abstract

Bismuth antimony telluride (BST), which was commercialized as a thermoelectric material for application in the low temperature range of less than 500 K, has been actively researched. Among the various methods for increasing the thermoelectric performance of BST, an approach to improving the power factor by adjusting the electrical conductivity and the Seebeck coefficient has been proposed. Nanostructured carbon materials with excellent electrical conductivity to enhance the power factor can be expected to exhibit excellent thermoelectric performance when the carrier concentration and the carrier mobility are controlled. Among these nanostructured carbon materials, single-walled carbon nanohorns (SWCNHs) with sea-urchin-like aggregates of approximately 100 nm in diameter have high dispersibility in various solvents and matrix materials, which is advantageous for manufacturing composites and improving electrical characteristics. The highest power factor of (3.96 mW m？1K？2) which was 1.4 times higher than that of pure BST (2.83 mW m？1K？2) was obtained from the BST/SWCNHs composite with a content of 0.5 wt% SWCNHs. The use of a nanostructured SWCNH filler improved the electrical properties and thereby enhanced the thermoelectric effect.