Structural, optical, thermal and electrochemical properties of rGO/PEDOT:PSS/PVP composite for supercapacitor electrode application

In the present work, reduced graphene oxide (rGO)/poly(3,4-ethylene dioxythiophene) polystyrene sulphonate (PEDOT:PSS)/polyvinylpyrrolidone (PVP) composite films are synthesized with varying rGO content from 0 to 25wt.%. The estimated average particles’ sizes evaluated from scanning electron microscope of rGO/PEDOT:PSS/PVP are found to be in the range between 2.43 µm and 4.11 µm. The broad XRD peak at 2 θ ~ 21.4 o to 23° corresponds to (002) plane of rGO in rGO/PEDOT:PSS/PVP. The FTIR results at 829, 1287, 1344, 1413, 1421, 1642, 2950 and 3393 cm −1 correspond to vibration bonding of (C–S), (C–C), (S–O), (C–O–H), (C–N), (C=O), (C–H) and (O–H) respectively. The Raman spectra, I D / I G ratio varies from 0.31 to 0.35 for 15–25 wt%, indicating that the nitrogen bonding with carbon atom decreased with increasing rGO content. The absorption spectra at ~ 243.9 nm and 281.2 nm correspond to ( p – p *) and ( n – p *) transitions respectively from 15 to 25 wt% of rGO. Form Tauc’s plot optical bandgap was decreased from 5.2 to 4.79 eV with increasing of rGO contents. Thermal gravimetric analysis (TGA) spectrum indicates that thermal degradation of the rGO/PEDOT:PSS/PVP composite starts above ~ 350 °C. From CV analysis, the maximum specific capacitance was found to be 447.14 F/g and from the galvanic charge–discharge curve, the maximum specific capacitance was found to be 225.71 A/g for 25 wt% rGO content rGO/PEDOT:PSS/PVP.