Study on the fabrication and characterization of LAST and LASTT based thermoelectric generators

Thermoelectric modules are of great interest for power generation applications where temperature gradients of approximately 500K exist, and hot side temperatures near 800K. The fabrication of such modules requires optimization of the material compositions, low contact resistivities, and low thermal loss. AgPb_mSbTe_2+m (LAST) and Ag(Pb _1-xSn_x)_m SbTe_2+m (LASTT) compounds are among the best known materials appropriate for this temperature range. Various measurement systems have been developed and used to characterize bulk samples in the LAST and LASTT systems within this operating temperature range. From the characterized data, modeling of modules based on these materials and segmented legs using LAST(T) with Bi₂Te₃ have been used to identify the optimal geometry for the individual legs, and the length of the Bi₂Te₃ segments. We have segmented LAST(T) with Bi ₂Te₃ and achieved contact resistivities of less than 10 μΩ·cm². Here we give a detailed presentation on the procedures used in the fabrication of thermoelectric generators based on LAST, LASTT, and segmented with Bi₂Te₃ materials. We also present the output data on these generators.