Thermoelectric Material Synthesis and Characterization

Since the discovery of thermoelectric (TE) materials, they have been of much interest to the scientific community because they are able to convert thermal energy to electrical energy and, inversely, utilize electrical energy to create temperature gradients. This allows for TEs to recycle heat energy lost from processes, reducing energy consumption and increasing efficiency. These materials have many advantages over traditional heating and cooling appliances and power generators, for example noiseless operation, no moving parts, and no fluids such as freon. Despite these properties, TEs currently lack high power conversion.1 To improve these, n- and p-type dopants are added to create distortions in the crystal structure to increase phonon scattering. Increased scattering is also found in nanoscale TEs. TEs are usually synthesized using solid-state high energy routes such as ball milling which tend to have low yields.2 We utilize an alternative solution phase approach, modified polyol synthesis, to make TE nanoparticles.2 Appropriate metal salts are dissolved in tetraethylene glycol, reduced in solution by sodium borohydride, and heated. These nanoparticles are characterized primarily by X-ray diffraction spectroscopy and scanning electron microscopy. The focus of this research has been the optimization of this synthetic method and the fabrication of novel materials. 1. Wang, R. Y., Feser, J. P., Gu, X., Yu, K., Segalman, R. A., Majumdar, A., Millirion, D. J., Urban, J. J. Universal and Solution-Processable Precursor to Bismuth Chalcogenide Thermoelectrics. Chem. Mater. 2010, 22, 1943-1945. 2. Anderson, M. E., Bharadwaya, S. S. N., Schaak, R. E. Modified Polyol Synthesis of Bulk-Scale Nanostructured Bismuth Antimony Telluride. J. Mater. Chem. 2010, xx, 1-7