Thermoelectric properties of Polythiophene/MWNT composites prepared by ball-milling

Polythiophene /multi-wall carbon nanotubes (MWNT) composites were prepared by ball-mailing. The morphology and internal structure of the composites were evaluated by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD). Their thermoelectric properties, i.e., the electrical conductivity, the Seebeck coefficient and the thermal conductivity, were investigated in detail. The results showed that the MWNT were uniformly dispersed in the polymer matrix, and that increasing the electrical conductivity is the key factor for enhancing the thermoelectric figure of merit at MWNT content below 70 wt%; with MWNT content beyond 70 wt%, the decrease of Seebeck coefficient and the increase of thermal conductivity led to the decrease of the thermoelectric figure of merit of the composites. The highest ZT is 2.43x10(-4) for the 70 wt% MWNT. This study suggests a simple way to improve the thermoelectric performances of conducting polymers.