One pot green synthesis of graphene-iron oxide nanocomposite (GINC): an efficient material for enhancement of thermoelectric performance

We report for the first time, a green method for graphene-iron oxide nanocomposite (GINC) synthesis by dispersing graphene and nano iron oxide (Fe2O3) in ethanol via ultrasonication followed by micro-wave irradiation. This is a simple method of making a broader range of graphene-metal oxide nanocomposites with excellent dispersion of 3D nanoparticles over 2D graphene. In addition, we have also demonstrated the synthesis of highly conductive PVAc-GINC and PVAc-graphene composites by ultrasonication followed by hot compaction for thermoelectric application. Graphene and GINC concentration were judiciously varied and optimized for the sake of high electrical conductivity and Seebeck coefficient. The fabricated PVAc-GINC film exhibited a conductivity of 2.18 x 10(4) S m(-1) with a Seebeck coefficient of 38.8 mVK(-1). Hence, the power factor (PF) reaches 32.90 mu Wm(-1) K-2, which is 27 fold higher than the thermoelectric material based on PVAc-graphene composite. This PF value is found to be the maximal ever reported without using conducting polymer.