Thermoelectric properties of the thallium-tellurium binary compounds

Abstract

We are paying attention to extremely low thermal conductivity (k) materials which have a potential to be next generation thermoelectric materials. Most of the extremely low Kmaterials that have been reported so far are ternary thallium tellurides such as Ag-Tl-Te ternary system. However, as for Tl-Te binary system, the thermoelectric properties have been scarcely reported. In the present study, the Tl-Te binary compounds, Tl2Te, Tl 5Te3, TlTe, and Tl2Te3, were prepared and their thermoelectric properties were investigated. The Kof TlTe was relatively high (approximately 4 Wm-1 K-1 at 300 K), while those of T12Te and Tl2Te3 were extremely low (̃0.5 Wm-1 K-1 at 300 K). These compounds indicated relatively high thermoelectric figure of merit ZT, e.g., T12Te showed the highest value of 0.2 at 586 K. ©2009 The Thermoelectrics Society of Japan.