Influence of graphene oxide surface treatment by diazonium salts on thermoelectrical behavior of polypyrrole-based composites

In this study, we investigate the influence of crude and surface-treated graphite by diazonium salt on the thermoelectric (TE) properties of six different mixtures of polypyrrole (PPy)-based ternary composites, which also contain poly(3,4- ethylenedioxythiophene) (PEDOT) or PEDOT:PSS and are prepared either by direct mixing procedure or copolymerization route according to an optimized formulation (Polymer I-Charges-Polymer II). The surface treatment, by 4-carboxybenzenediazonium tetrafluoroborate (DS-COOH), of reduced graphene oxide (FrGO) has been found to significantly improve TE properties of composites, wherein the higher obtained value of figure of merit (zT) has been greatened by a magnitude of 240 times comparatively to PPy alone. Moreover, composites obtained by the direct mixing process of component has exhibited more than twice the value of zT than that of composites obtained by the copolymerization method. Hence, surface treatment of FrGO by diazonium salt refines its seeked role in improving TE properties of polymeric composites and makes it a promising element when incorporated within organic composites to reach higher TE features.