Enhanced thermoelectric performance of 3D-printed Bi2Te3-based materials via adding Te/Se

Bi2Te3-based materials were prepared by direct ink writing (DIW) 3D printing and their microstructure and thermoelectric properties were investigated with an emphasis on the effect of the content of DMF and Te/Se addition. As the mass ratio of DMF in the composition increased from 6.5% to 8.0% (in mass), the electrical conductivity deteriorated because of the corresponding increased porosity and organic remains in the samples. However, the volatilization of DMF would reduce the fluidity of the slurry. Thus, thermoelectric slurry with 7.0% DMF is the most suitable mass ratio for 3D printing. Additionally, adding Te in the p-type Bi0.4Sb1.6Te3 and adding Se in the n-type Bi2Te2.6Se0.4 have significantly improved their electrical conductivity due to the increased carrier concentration and mobility. Combining with the moderate Seebeck coefficient (-200 mV/K), high power factors with-802 mW center dot m-1 center dot K-2 and 1266 mW center dot m-1 center dot K-2 were obtained for the n-type Bi2Te2.6Se0.4+10%Se and p-type Bi0.4Sb1.6Te3+7%Te, respectively, which result in the final relatively high zT values of 0.68 at 573 K and 0.56 at 330 K for n -type and p-type 3D-printed samples.(c) 2022 The Authors. Published by Elsevier B.V. on behalf of The Chinese Ceramic Society. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

Bi2Te3-based materials were prepared by direct ink writing (DIW) 3D printing. The effect of DMF content and Te/Se addition on the microstructure and thermoelectric properties was investigated. Increasing DMF content led to decreased electrical conductivity due to increased porosity and organic remains. However, the volatilization of DMF reduced the fluidity of the slurry, making a 7.0% DMF content most suitable for 3D printing. Additionally, adding Te or Se significantly improved the electrical conductivity of the materials.