High performance wearable thermoelectric generators using Ag2Se films with large carrier mobility

Flexible thermoelectric generators are suitable for powering wearable electronic devices. In this work, single-phase AgxSe (x = 1.6, 1.8, 2.0, and 2.2) films were successfully deposited on the polyimide substrate by thermal evaporation. An extraordinary high electron mobility was achieved in the ab-plane of Ag1.8Se film because of the highly orientation and crystallization, as well as the lowered effective mass, leading to a high room-temperature power factor of ~17 μW cm−1 K−2 and a peak power factor of ~19 μW cm−1 K−2 at 380 K. A 4-leg flexible thermoelectric generator composed of the Ag1.8Se film demonstrates a maximum power density of 46.8 W m−2 working at the temperature difference of 50 K, and a robust mechanical property with negligible change in the device resistivity upon 1000 times bending. An output voltage of 3.5 mV and an output power of about 2.3 nW were obtained as dressed on the arm.