Modulation of charge transport properties in poly(3,4-ethylenedioxythiophene) nanocomposites for thermoelectric applications

Conjugated polymer poly(3,4-dioxyethylenthiofene) (PEDOT) has recently gained attention for room-temperature thermoelectric applications due to its low cost, safety, and the possibility to easily process it. This makes it an interesting prospective alternative to tellurides commonly used around room temperature. Still low thermoelectric efficiencies of polymers might be more easily increased, were a model of its transport properties available. Aim of this paper is to validate a model recently reported, making use of the concept of transport energy to frame the onset of transport properties reported over the last years in the literature. To this aim, PEDOT and PEDOT-based nanocomposites embedding CuO nanoplatelets were prepared and analysed. We found that the model adequately fits the trends observed in pure PEDOT and in its nanocomposites. Transport and Fermi energy were verified to depend on the polymer oxidation level only, while the transport coefficient was found to be sensitive to PEDOT stacking and was modulated by the introduction of CuO nanoplatelets.