Towards Thermoelectric Weaves: Thermal Conductivity of Bi₂Te₃ Ribbons Using the Suspended 3ω Method.

Woven thermoelectric devices are important for conformal thermal energy harvesting in systems where traditional, more rigid, thermoelectric generators are not practical. For this purpose, it is necessary to characterize candidate materials for use in thermoelectric weaves. One such candidate is Bi₂Te₃, a well-researched material with high thermoelectric performance. Normally rigid, Bi₂Te₃ can be made into thin, flexible ribbons, ideal for our purposes. To that end, we measured the thermal conductivity of thin p-type Bi₂Te₃ ribbons using the suspended 3ω method. To our knowledge, this has not yet been done for Bi₂Te₃ in this configuration. We exfoliated these ribbons using a modified scotch-tape method and constructed an integrated measurement platform that allows us to measure all relevant parameters needed to calculate the figure of merit ZT with very little or no modification between measurement set ups. Our measurement of the average thermal conductivity was 4 W/mK, which is much higher than literature values, of order 1.5 W/mK. Improvements in this novel measurement method will therefore be explored in upcoming experiments. In addition to these results, new data on n-type Bi₂Te₃ ribbons will also be presented.