Conjugated Polymer Nanocomposite: Towards a Novel Material for Thermal Energy Microharversting

Conjugated polymers have recently gained attention as a valuable choice for electronics applications, due to their low cost, easy processability and environmental stability. Furthermore, safety and flexibility of these materials are interesting features for wearable electronics. Example of this application are thermoelectric body harvesters, i.e. flexible devices able to collect body heat and to convert it into electrical energy. To this aim, still low thermoelectrical power factor (PF) of conjugated polymers has to be improved. A strategy to reach this goal is nanostructuration of the material: such approach aims to generate energy filtering effect, which is known to cause a PF increase in inorganic semiconductors. The path to obtain samples of nanostructured polymer-based material has been to embed inorganic nanoparticles (NPs) with suitable electronic features, i.e. Mn 3 O 4 NPs, into poly(3,4-ethylendioxithiophene):tosylate, or PEDOT:Tos. The NPs have been grafted with succinyl-EDOT and suspended in the polymerization solution, then hybrid films are obtained by in situ polymerization technique. The study on such samples was focused on the influence of the NP density (NP DLS diameter 120±20 nm) on thermoelectrical properties. A conductivity of 240 S/cm and a Seebeck coefficient of 15 V/K were measured for a NP density of 4 . 10 11 cm -3 , while lower conductivities characterized higher NP densities films. An outlook of the possible improvement strategies will be given. (1) Kim, M.-K.; Kim, M.-S.; Lee, S.; Kim, C.; Kim, Y.-J. Smart Mater. Struct. 2014, 23 (10), 105002.Kim, S. J.; We, J. H.; Cho, B. J. Energy Environ. Sci. 2014, 7 (6), 1959. (2) Kim, G.-H.; Shao, L.; Zhang, K.; Pipe, K. P. Nat Mater 2013, 12 (8), 719–723. (3) Neophytou, N.; Zianni, X.; Kosina, H.; Frabboni, S.; Lorenzi, B.; Narducci, D. Nanotechnology 2013, 24, 205402.