Improvement of thermoelectric properties of composite films of PEDOT-PSS with xylitol by means of stretching and solvent treatment

Organic thermoelectric materials have advantages, such as their use in the easy and low-cost fabrication of flexible devices with a large area that can convert waste heat energy into electricity and vice versa. The critical point of the materials is their electroconductivity and flexibility for practical applications. Stiff and brittle poly(3,4-ethylenedioxythiophene) poly(4-styrenesulfonate) films are known to become flexible by forming composites with xylitol. Thus, we prepared flexible poly(3,4-ethylenedioxythiophene) poly(4-styrenesulfonate)/xylitol composite films and evaluated their thermoelectric properties. Stretching the composite films, fabricating composite films by adding dimethyl sulfoxide, and treating the films with dimethyl sulfoxide and/or pure water were found to increase the electrical conductivity and improve the thermoelectric properties of the films.