Large-area, stretchable, super flexible and mechanically stable thermoelectric films of polymer/carbon nanotube composites

Recently, due to their unique advantages over inorganic materials, organic polymer thermoelectric (TE) materials have received considerable attention. However, most studies focus on TE performance enhancement. So far, little attention has been paid to large-area preparation, stretchability, super flexibility and mechanical stability, although these are the intrinsic advantages of polymer materials. Here we report for the first time large-area, stretchable, super flexible and mechanically stable TE films of polymer/carbon nanotube composites. Mechanically stretchable films with a diameter of similar to 18 cm are achieved by common vacuum filtration, whose thicknesses and sizes can be conveniently adjusted. Despite direct observations of films under various deformations of bending, rolling or twisting, quantitative measurements of minimum bending radii (<0.6 mm) further confirm the super flexibility. More importantly, after mechanical bending or stretching, no obvious deterioration of TE performance is found. Our findings represent a novel direction of polymer TE materials, and will speed up their applications.