High performance Ag2Se films by a one-pot method for a flexible thermoelectric generator

Abstract

Herein, a novel and facile method to fabricate a flexible Ag₂Se thermoelectric (TE) film on a nylon substrate is developed. The Ag₂Se film was prepared by vacuum-assisted filtration of the Ag₂Se powder synthesized by a one-pot method followed by hot pressing. An optimal Ag₂Se film shows a maximum power factor of ∼2043 μW m⁻¹ K⁻² at 300 K, which is one of the highest values reported for Ag₂Se films on flexible substrates. The excellent performance of the film is mainly due to the high density and good crystallinity of Ag₂Se grains with semi-coherent and coherent grain boundaries. Besides, the film also shows good flexibility. Furthermore, a 6-leg flexible TE generator (f-TEG) assembled from the optimal film produces a maximum power of ∼9.14 μW (corresponding power density of ∼30.46 W m⁻²) at a temperature gradient of 30.3 K, which proves that the film has exceptionally high TE properties. This work presents a simple, fast, low cost and environmentally friendly synthesis process for preparation of high performance Ag₂Se-based flexible TE films.