Segmented thermoelectric unicouple for an operating temperature range of 30–320$^\circ$C

The possibility of increasing the efficiency of a thermocouple in the temperature range of 30–320$^\circ$C is studied using an approach associated with the development of segmented thermoelectric unicouples. $n$- and $p$-type thermoelectric unicouples are constructed from low-temperature thermoelectric materials based on bismuth telluride and the addition of an intermediate-temperature material based on PbTe and GeTe, respectively. The thermoelectric unicouples are fabricated by spark plasma sintering (SPS). This method provides a contact resistance of $\le$ 10$\mu\Omega$ cm. The properties of segmented and conventional unicouples are compared. The efficiency of segmented unicouples in comparison with conventional ones increases by almost 70% and attains 5.3% in the operating range of 30–320$^\circ$C.