Development of low resistance electrical contacts for thermoelectric devices based on n-type PbTe and p-type TAGS-85 ((AgSbTe2)0.15(GeTe)0.85)

Diffusion bonded very low resistance electrical contacts (specific contact resistance < 10 muOmega cm2) have been developed on n-type PbTe and p-type TAGS-85 ((AgSbTe2)0.15(GeTe)0.85) thermoelements. Thermoelectric devices (TEDs) having two p-n couples in series (each of four elements having 7.5 mm diameter) generated an output power of 1.2 W (at an operating current of ~17 A) at hot side temperature Th = 500 deg C and a temperature difference DeltaT = 410 deg C. Internal resistance of the devices was found to increase linearly with an increase in the number of thermoelements. The efficiency of developed TEDs was found to be 6%. The devices have been operated continuously for more than 8 months in air without any degradation of the output power.