Enhanced-Performance PEDOT:PSS/Cu₂Se-Based Composite Films for Wearable Thermoelectric Power Generators

Herein, we report the preparation and thermoelectric (TE) properties of flexible PEDOT:PSS/Cu₂Se-based nanocomposite films on a nylon membrane using facile vacuum filtration and then hot pressing. The main composition of the composite film changed during hot pressing, causing the change of the carrier transport and TE performance intensively. Consequently, the optimized film shows a high power factor of 820 μW/mK² at 400 K, which is 3 times as high as that of the nonhot-pressed one. The film shows excellent flexibility with 85% retention of the power factor after 1000 bending cycles around a 5 mm diameter rod. The outstanding flexibility results from a good combination between the nylon membrane and the Cu₂Se-based nanoporous structured film. By pairing with n-type PEDOT/Ag₂Se/CuAgSe films, a ten-legged flexible TE generator outputs maximum voltage and power of 50 mV and 1.55 μW, respectively, at a temperature difference of 44 K. Our research opens up a promising avenue to design high property flexible TE films for energy conversion.