A prototype thermoelectric module based on p-type colusite together with n-type nanostructured PbTe for power generation

Thermoelectric power generation from the prototype pi-shaped module composed of p-type colusite (Cu26Cr2Ge6S32) and n-type nanostructured PbTe (Pb0.98Ga0.02Te-3% GeTe) was demonstrated in this study. The thermoelectric figure of merit zT of Cu26Cr2Ge6S32 and Pb0.98Ga0.02Te-3% GeTe was & SIM;0.8 and & SIM;1.2 at 665 K, respectively. In PbTe, transmission electron microscopic images and energy-dispersive x-ray elemental maps reveal the insertion of nanoscale precipitates induced by the GeTe alloying. Contact layers based on Au and Co-Fe were used for p- and n-type thermoelectric legs, respectively, which allow the low electrical specific contact resistances of & LE;10 x 10(-10) omega m(2) at room temperature. Maximum thermoelectric conversion efficiency eta(max) of & SIM;5.5% was obtained for the Cu26Cr2Ge6S32 and Pb0.98Ga0.02Te-3% GeTe-based two-pair module when the hot-side T-h and cold-side T-c temperatures were maintained at 673 and 283 K, respectively. A three-dimensional finite-element simulation predicts the eta(max) of & SIM;7.1% for the module at T-h and T-c of 673 and 283 K, respectively.