posted on 2023-11-21, 07:13authored byNirma Kumari, Amit Singh, Titas Dasgupta
Parasitic losses at various interfaces play a crucial
role in determining
the thermoelectric (TE) generator performance. In this work, we adopt
an approach wherein the interface contact resistance can be minimized
by using a combination of the multilayer (ML) contacting technique
and transient liquid phase (TLP) bonding. The technique was experimentally
verified with doped Mg3Sb1.5Bi0.5. First, a contacted leg consisting of the TE material, the diffusion
barrier layer, and an outer metallic (copper) layer was prepared by
the ML process. This was then joined to a copper bridge (mimicked
by copper holders) by using the TLP process with tin as the brazing
element. Our contact resistance measurements indicate an extremely
low value corresponding to 2.5% of the total resistance for the TLP-joined
layer, which corresponds to a ∼2.6% lowering of the peak efficiency
(ηmax) value compared to that of
an uncontacted leg. Thermoelectric generator (TEG) measurements were
obtained for the contacted leg. The contacted leg exhibited an ηmax value of ∼10% and a power output
of 80 mW when it was subjected to a temperature gradient (ΔT) of 330 K. These results demonstrate that, by combining
ML contacting with TLP bonding, interface contact engineering can
be a potential method for enhancing TE performance.