- Anil Kumar: Polymorphism of thermoelectric TAGS-85
- 13. 3. 2019, 14:10
- lecture room F2, first floor Ke Karlovu 5
- more information
Abstract:
The alloys (GeTe)X(AgSbTe2)1-X (commonly known as TAGS) are among the best high-temperature thermoelectric materials, largely due to their low thermal conductivity. Here we focus on TAGS-85, which is reported to have a transition from a rhombohedral phase to a cubic phase above ~200 °C. We have found a way to stabilize both of these polymorphs at room temperature by careful adjustment of the synthesis conditions. We study the structural properties of both rhombohedral and cubic TAGS-85 as a function of thermal cycling and reveal a much more complex behavior than previously reported, involving transformations to novel layered structures. The thermoelectric properties of both polymorphs will be discussed with respect to their electrical conductivity, Seebeck coefficient and thermal conductivity.