Materials development and module fabrication in highly efficient lead tellurides

This chapter discusses new strategies leading to significant improvements in the thermoelectric figure of merit (ZT) and examines recent advances in module fabrication of lead telluride (PbTe)-based materials. PbTe is a traditional thermoelectric material for high-temperature use (600-900K); its ZT value continues to increase with the application of new strategies and have exceeded ~2.5 for p-type PbTe and ~1.8 for n-type PbTe. The reduction in lattice thermal conductivity by nanostructuring/hierarchical architecturing has been intensively studied in PbTe-based materials. The improvement of thermoelectric power factor by electronic band engineering has also been extensively developed in PbTe. The technology transfer between material development and module fabrication has already begun with the newly developed high-ZT PbTe. An efficiency of ~12% has been demonstrated in a cascade-type module made of nanostructured PbTe and Bi₂Te₃ for a hot-side temperature of 873K and a cold-side temperature of 283K.