Ag2Se/nylon self-supporting composite films for wearable photo-thermoelectric generators with high output characteristics

Abstract

Recently, the skyrocketing interest in smart wearable devices has led to innovations in energy-harvesting materials. Flexible thermoelectric (TE) materials have thus developed rapidly, but in this process TE performances have been over pursued, leaving the research of more practical TE self-supporting films at a less advanced level. In this work, Ag₂Se/nylon self-supporting composite films with both excellent flexibility and leading TE performances (874.3 and 1825.1 μW m⁻¹ K⁻² with 80 and 90 wt% Ag₂Se contents) were prepared by sequential chemical silver plating, selenization reaction and vacuum hot-pressing processes using nylon mesh as the flexible backbone, and the excellent photothermal (PT) effect of Ag₂Se was introduced into the TE field for the first time to build a homogeneous synchronous photo-thermoelectric generator (PTEG). The PTEG can produce a high output voltage and power of 8.8 mV and 8.36 μW with low power NIR light irradiation of 100 mW cm⁻² without a cooling source, and considerable output characteristics under visible light irradiation of different intensities can also be acquired. The superior output power can be attributed to the outstanding TE and PT characteristics of the sample, as well as the thickness optimization due to the self-supporting film. This work provides a new idea for preparing high performance flexible TE self-supporting films and developing PTEGs with high output characteristics, and the PTEGs are expected to be applied to self-powered systems for wearable devices.