Facile preparation of flexible all organic PEDOT:PSS/methyl cellulose thermoelectric composite film by a screen printing process

Screen printing technology was employed to prepare flexible all organic poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)/methyl cellulose (MC) composite films on a polyvinylidene fluoride substrate. The influences of the contents of MC and dimethyl sulfoxide (DMSO) post-treatment on thermoelectric properties of the as-prepared PEDOT:PSS/MC composite films were investigated. The electrical conductivity of the PEDOT:PSS/MC composite films was decreased with the contents of MC increasing, whereas the Seebeck coefficient was kept almost constant. A maximum power factor of 2.1 μW m−1 K−2 was obtained at 360 K for the composite film containing 25.67 wt% MC. After the DMSO treatment, the power factor was increased to 16.2 µW m−1 K−2 at 340 K, which was ~7.7 times as that of the untreated composite film (2.1 μW m−1 K−2 at 360 K). The screen printing technology has the characteristics of easy operation and suitable for large-scale production, and therefore it is a great potential method for fabrication of flexible thermoelectric materials.