Thermoelectric conversion is a process of cooling and electrical generation, utilizing the fact that electrons in materials carry not only electrical charge but also heat energy. It is expected to have widespread applications, from topical cooling of specific areas that need to be cooled, to environmental power generation that derives electrical power from the natural fluctuations in temperature around us. However, we have yet to find materials that perform well in environments below minus 100 degrees Celsius, so the process only has limited use in environments close to room temperature, such as cooling of infrared sensors using bismuth-based materials. Our research focuses on the potential of a new tantalum-based material, Ta4SiTe4, to realize cooling and electrical power generation on a practical level in low-temperature environments. Our work to date has revealed that this material has a capacity for thermoelectric generation at low temperatures that greatly exceeds that of the materials currently in use. However, the material has only been formed as needle crystals of thicknesses of less than 10 microns, which is not sufficient to use for thermoelectric generation that usually requires bulk materials of several square millimeters. Applying a variety of different methods, we aim to synthesize a bulk specimen that can contribute to practical applications of thermoelectric generation that have not been possible to date.
