High performance n-type PbTe-based materials for thermoelectric applications

Lead telluride-based compounds are known for their favorable thermoelectric properties in the 50-600 °C temperature range. The transport properties of homogeneous, cold-compacted and sintered PbI2-doped PbTe samples were measured and compared to those of cast samples with similar dopant concentrations. Such a comparison is mandatory in order to determine the potential of graded samples, prepared by powder metallurgy, for thermoelectric applications. The present work focuses on improving the thermoelectric efficiency of PbTe-based materials by functional grading and by taking advantage of the specific features of indium as dopant element. The potential for achieving high thermoelectric efficiency in In-doped n-type PbTe-based thermoelectric compounds is described, and is compared to that of PbI2-doped PbTe. Design, synthesis and characterization procedures are reported for fabricating In- and PbI2-doped PbTe compounds with desired composition profiles.