Bi2Te3 exfoliated in liquid phase for flexible thermoelectrics

Around 60% of the energy used in processes is wasted as heat. Thermoelectric (TE) materials convert temperature gradients into an electric voltage. Since the work of Dresselhaus and Hicks, traditional TE semiconductors have been nanostructured to achieve improved TE conversion efficiencies. In this work the band-gap evolution on solvothermally exfoliated bismuth telluride using UV-vis, Raman spectra analysis and DFT calculations was investigated. A bandgap broadening was observed due to the exfoliation and a peak shifting in Raman spectra were found as the material became thinner. In addition, we report FTEGs modules made with exfoliated-Bismuth-telluride/Graphene composites which were screen-printed on polyester fabric. As a result, the module reached Seebeck coefficients of −45.38μV/K and 41.18μV/K for devices made with 100% graphene and a composite of 20% bismuth telluride/80% graphene dispersions, respectively.