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

## TL;DR

Researchers developed flexible thermoelectric materials using PEDOT:PSS and Bi2Te3 for wearable thermopiles, achieving energy harvesting from body heat.

## Contribution

A novel composite thermocouple material combining PEDOT:PSS and Bi2Te3 for wearable thermopile fabrication is introduced.

## Key findings

- The composite pastes showed sheet resistances of 26–264 Ω/sq and Seebeck coefficients of 14–45 μV/K.
- Textile thermopiles generated 6–8 mV at a 100 °C temperature gradient.
- Energy harvesting from body heat produced output voltages of around 0.3 mV.

## Abstract

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.