Chemical synthesis and enhanced electrical properties of bulk poly(3,4-ethylenedioxythiophene)/reduced graphene oxide nanocomposites

•PEDOT/rGO nanocomposite bulk is prepared by in situ micro-emulsion polymerization followed by cold-pressing and annealing.•Thermal treatment and rGO doping lead to enhanced electrical conductivity and thermoelectric power factor.•The enhanced electrical properties are mainly due to the optimized microstructure and rGO serving as conducting channels.

PEDOT, poly(3,4-ethylenedioxythiophene), is an important conjugated conducting polymer, and a complex salt PEDOT:PSS has been widely researched on account of its advantages of favorable workability, excellent film-forming ability and decent electrical conductivity. Although PEDOT films with excellent thermoelectric properties have already been intensively described in the literature, few reports focused on thermoelectric properties of bulk forms of PEDOT. Here, we report on bulk PEDOT and its composites with reduced graphene oxide (PEDOT/rGO) synthesized by a chemical method combined with cold pressing and thermal treatment. The impact of the rGO doping and the thermal treatment on the electrical transport properties of PEDOT and PEDOT/rGO is discussed. The results show that 0.44 wt% of rGO doping improves the electrical conductivity of PEDOT by a factor of about 2. The electrical conductivity of PEDOT/0.44 wt% rGO is further increased by about 3 times after the thermal treatment. Moreover, the power factor of bulk PEDOT is enhanced by a factor of 16 following the thermal treatment. The π–π interaction between rGO and PEDOT, the closer packing within the polymer matrix, as well as the more ordered structure within the polymer matrix induced by the thermal treatment and the addition of rGO are of crucial importance for the remarkable improvement of the electrical conductivity and the power factor.