Flexible thermoelectric (TE) generators have recently attracted increasing attention as they have the potential to power wearable devices using the temperature difference between the human body and the environment. Ag2S is recently reported to have plasticity near room temperature; however, it has very low electrical conductivity, leading to its poor TE property. Here, to improve the TE property, different amounts of Se (Se/Ag2S molar ratios being 0.4, 0.5, and 0.6) solid solution-substituted Ag2S films on a nylon membrane are prepared by combing wet-chemical synthesis, vacuum filtration, and hot-pressing. The film (Se/Ag2S molar ratio = 0.6) exhibits a better TE performance with a power factor of 477.4 ± 15.20 μW m-1 K-2 at room temperature, which is comparable to that of bulk Ag2S1-xSex. In addition, the film possesses excellent flexibility (only ∼5.4% decrease in electrical conductivity after 2000 times bending along a rod with a radius of 4 mm). The power density of a 6-leg TE generator assembled with the film is 6.6 W/m2 under a temperature difference of 28.8 K. This work provides a facile new route to Ag2S-based TE films with low cost, high TE performance, and ultrahigh flexibility.
Keywords: Ag2S; Se; flexibility; power generator; thermoelectric film.