Researches on flexible thermoelectric materials usually focus on conducting polymers and conducting polymer-based composites; however, it is a great challenge to obtain high thermoelectric properties comparable to inorganic counterparts. Here, we report an n-type Ag₂Se film on flexible nylon membrane with an ultrahigh power factor ~987.4 ± 104.1 μWm⁻¹K⁻² at 300 K and an excellent flexibility (93% of the original electrical conductivity retention after 1000 bending cycles around a 8-mm diameter rod). The flexibility is attributed to a synergetic effect of the nylon membrane and the Ag₂Se film intertwined with numerous high-aspect-ratio Ag₂Se grains. A thermoelectric prototype composed of 4-leg of the Ag₂Se film generates a voltage and a maximum power of 18 mV and 460 nW, respectively, at a temperature difference of 30 K. This work opens opportunities of searching for high performance thermoelectric film for flexible thermoelectric devices.

Herein, we demonstrate that a flexible, air-permeable, thermoelectric (TE) power generator can be prepared by applying a TE polymer (e.g. poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate)) coated commercial fabric and subsequently by linking the coated strips with a conductive connection (e.g. using fine metal wires). The poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) coated fabric shows very stable TE properties from 300 K to 390 K. The fabric device can generate a TE voltage output (V) of 4.3 mV at a temperature difference (ΔT) of 75.2 K. The potential for using fabric TE devices to harvest body temperature energy has been discussed. Fabric-based TE devices may be useful for the development of new power generating clothing and self-powered wearable electronics.

A highly flexible Ag ₂ Se based composite film on nylon with a record power factor is prepared for thermoelectric generators.