Extremely Low Thermal Conductivity Substances as Novel Thermoelectric Materials

Abstract

ABSTRACTWe have prepared polycrystalline bulk samples of various thallium compounds and measured their thermoelectric properties. The most remarkable point of the thermoelectric properties of the thallium compounds is the extremely low thermal conductivity. The state-of-the-art thermoelectric materials such as Bi2Te3 and TAGS materials indicate relatively low the thermal conductivity, around 1.5 W/m/K. However, the thermal conductivity of the thallium compounds is below 0.5 W/m/K; especially that of silver thallium tellurides is around 0.25 W/m/K at room temperature. This extremely low thermal conductivity leads a great advantage for an enhancement of the thermoelectric performance. In this paper, we report on the properties of some thallium compounds selected for study as novel thermoelectric materials. One of these compounds seems to have a thermoelectric figure of merit comparable to those of state-of-the-art materials.