Dissecting the Role of Reduced Graphene Oxide on the Dielectric Properties of Poly(vinyl alcohol)/Poly(3,4-ethylenedioxythiophene):Poly(styrenesulfonate) Blend

Herein, we present the fabrication of freestanding films of a reduced graphene oxide–poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)–poly(vinyl alcohol) (RGO–PEDOT:PSS–PVA) composite through a solution blending method at optimal synthesis conditions and varied RGO concentration. The frequency- and temperature-dependent dielectric properties were measured within the temperature range of 303–523 K for the frequency range 102–106 Hz. The temperature-dependent dielectric spectra suggest that, at the low-temperature regime (<358 K), polarization occurs due to the water molecules or -OH groups present in the composite, which is supported by the thermogravimetric analysis of the sample. Above 358 K and 100 Hz, the steep rise in the dielectric constant (ε′) and dielectric loss (ε″) to the order of 105 and 106, respectively, suggests an increase in the dc conductivity due to percolation of charge carriers. The RGO acts as a channel for charge percolation and transport and forms a barrier between the PVA and PEDOT:PSS through intermolecular hydrogen bonding and π−π interaction between the thiophene ring in PEDOT:PSS and sp2 carbon of RGO. The FTIR and microRaman data supports our claim along with dc conductivity data obtained from the Havriliak–Negami model. The temperature-dependent dielectric studies suggest the role of RGO in the polarization and relaxation mechanism of the composite and give an idea about the range of temperature at which the sample can be effectively used as a dielectric for practical use.