Fabrication and characterization of thermoelectric power generators with segmented legs synthesized by one-step spark plasma sintering

A thermoelectric (TE) power generator with eight pairs of segmented TE legs was fabricated and characterized. The segmented TE legs were synthesized by one-step spark plasma sintering (SPS), including n-type Bi2Te3/PbSe0.5Te0.5 and p-type Bi0.3Sb1.7Te3/Zn4Sb3 legs. They were assembled on AlN substrates with patterned Cu electrodes by soldering to form a thermoelectric generator (TEG). Power generation of the TEG was measured using a desktop TEG testing instrument. A maximum output power of 48.6 mW was obtained at a temperature difference of 296 K. The Seebeck voltage of the segmented TE legs was 17.4% less than the theoretical value, which was satisfactory. The electrical resistance of the segmented legs was dramatically increased in comparison with that of the bulk materials, which was due to the large interfacial resistance between different segments in the TE legs; therefore, the interfacial resistance was found to be one of the key factors limiting the power generation of the segmented TEG. The output power of the segmented TEG without interfacial resistance was predicted to be 165.9 mW, and the corresponding efficiency was 1.53%. The experimental and simulation data demonstrate that it is feasible to fabricate a high-performance TEG with segmented legs synthesized by one-step SPS.