Thermoelectric behavior of PEDOT:PSS/CNT/graphene composites

Hybrids of poly(3,4-ethylenedioxythiophene) (PEDOT): poly(4-styrene sulfonate) (PSS)/multi-walled carbon nanotube (MWCNT)/graphene (P/M/G), which have high electrical conductivity and low thermal conductivity, were successfully prepared in aqueous solution through in situ polymerization of 3,4-ethylenedioxythiophene (EDOT) monomers in the presence of poly(sodium 4-styrene sulfonate) (PSSNa). Meanwhile, the composites were characterized by Raman spectroscopy, infrared (IR) spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy. Thermoelectric properties of the samples were measured at room temperature and 50 degrees C. Compared with pristine PEDOT: PSS (P), PEDOT: PSS/MWCNT (P/M) and PEDOT: PSS/graphene (P/G), the power factor of P/M/G composites was significantly improved, whatever the temperature. It increased from 0.061 mu W/mK(2) to 0.105 mu W/mK(2) at room temperature and from 0.070 mu W/mK(2) to 0.142 mu W/mK(2) at 50 degrees C, meaning 72% and 103% enhancement, respectively. The increased power factor is attributed to the synergic effects of MWCNT and graphene, a hybrid structure with excellent electronic coupling and more electric channels.