Highly conducting free-standing poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) films with improved thermoelectric performances

Highly conducting free-standing poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT/PSS) films with room-temperature electrical conductivity of about 300 S cm−1 were successfully prepared from PEDOT/PSS solution containing additives (DMSO or EG) on the smooth and flexible polypropylene (PP) film substrate with contact angle of 87°. As formed free-standing PEDOT/PSS films possess good flexibility and can be easily cut into various shapes with a knife. The contact angle of substrate has significant effect on the preparation of free-standing PEDOT/PSS films. Additionally, the process of adding DMSO or EG did not result in the change of carrier concentration but the increase of carrier mobility. The free-standing PEDOT/PSS film showed high electrical conductivity and stable Seebeck coefficient and its figure of merit (ZT) with high environment stability can be up to 10−2, one order of magnitude higher than that of pressed PEDOT/PSS pellets (10−3).