ICT2014 Abstracts

The practical use of thermoelectric materials for commercial devices requires analysis of the thermal stability in order to approximate the operating temperatures of materials. It is long known that both lead telluride and germanium telluride are very efficient thermoelectric materials but possess high vapor pressure near their operating temperature. However complete analysis of evaporation rates to better design devices had not been published. The evaporation rates of four state of the art materials had been tested in this research. The materials chosen were (1) Iodine doped PbTe (2) Undoped Lead Tin Telluride (3) TAGS-85 and (4) Pb_0.13Ge_0.87Te doped with 3% Bi₂Te₃. The materials were tested under dynamic conditions of heating at 3°C/min and at steady state conditions for 20 hours at 500°C for the GeTe alloys and 600°C for the PbTe alloys. The results from the dynamic and steady state testing were comparable at a factor of 1.5-3. The proposed operation temperature for both of the PbTe based alloys for a 5x5 mm leg, is 490-510°C for an area reduction of 10%-20% over 10 years. The proposed operation temperature for both of the GeTe based alloys for a 5x5 mm leg, is 410-430°C for an area reduction of 10%-20% over 10 years.