Synthesis and thermoelectric characterisation of bismuth nanoparticles

An effective method of preparation of bismuth nanopowders by thermal decomposition of bismuth dodecyl-mercaptide Bi(SC₁₂H₂₅)₃ and preliminary results on their thermoelectric properties are reported. The thermolysis process leads to Bi nanoparticles due to the efficient capping agent effect of the dodecyl-disulfide by-product, which strongly bonds the surface of the Bi clusters, preventing their aggregation and significantly reducing their growth rate. The structure and morphology of the thermolysis products were investigated by differential scanning calorimetry, thermogravimetry, X-ray diffractometry, ¹H nuclear magnetic resonance spectroscopy, scanning electron microscopy, and energy dispersive spectroscopy. It has been shown that the prepared Bi nanopowder consists of spherical shape nanoparticles, with the average diameter depending on the thermolysis temperature. The first results on the thermoelectric characterization of the prepared Bi nanopowders reveal a peculiar behavior characterized by a semimetal–semiconductor transition, and a significant increase in the Seebeck coefficient when compared to bulk Bi in the case of the lowest grain size (170 nm).