Development of Composite Thermocouple Materials Using PEDOT:PSS and Bi₂Te₃ for Wearables Thermopiles

This paper presents results on the preparation of thermoelectric composite materials for flexible and wearable electronics applications. Composite materials in the form of pastes for screen printing or stencil printing were made from a mixture of PEDOT:PSS paste and Bi₂Te₃ powder. The pastes showed good adhesion both to polyimide foil (Kapton) and polyester fabric substrates. Depending on the composition and the substrate used, the pastes had a sheet resistance of 26-264 Ω/sq, a Seebeck coefficient of 14-45 μV/K and a power factor of 0.05-0.8 μW/mK². The obtained pastes enabled the fabrication of textile thermopiles using Ag and PEDOT:PSS/Bi₂Te₃ materials for both arms. The output voltage of the obtained thermopiles on textile and foil substrates was 6-8 mV at a temperature gradient of 100 °C, and the output power was 0.01-0.12 μW. Energy harvesting from the human-ambient temperature gradient using the developed generators yielded promising results, with output voltages around 0.3 mV.