Pb1-xSnxTe Alloys: Application Considerations

The search for alternative energy sources is at the forefront of applied research. In this context, thermoelectricity, i.e., direct conversion of thermal into electrical energy, plays an important role, particularly for exploitation of waste heat. Materials for such applications should exhibit thermoelectric potential and mechanical stability. PbTe-based compounds include well-known n-type and p-type compounds for thermoelectric applications in the 50A degrees C to 600A degrees C temperature range. This paper is concerned with the mechanical and transport properties of p-type Pb0.5Sn0.5Te:Te and PbTe < Na > samples, both of which have a hole concentration of similar to 1 x 10(20) cm(-3). The ZT values of PbTe < Na > were found to be higher than those of Pb0.5Sn0.5Te:Te, and they exhibited a maximal value of 0.8 compared with 0.5 for Pb0.5Sn0.5Te:Te at 450A degrees C. However, the microhardness value of 49 H-V found for Pb0.5Sn0.5Te:Te was closer to that of the mechanically stable n-type PbTe (30 H-V) than to that of PbTe < Na > (71 H-V). Thus, although lower ZT values were obtained, from a mechanical point of view Pb0.5Sn0.5Te:Te is preferable over PbTe < Na > for practical applications.