Electrical, optical and dielectric properties of polyvinylpyrrolidone/ graphene nanoplatelet nanocomposites

In this study, polyvinylpyrrolidone (PVP) nanocomposite films containing GnP in four different volume fractions (phi = 0.00, 2.00, 4.08, and 5.91) were prepared by the solution casting method. UV-Vis absorbance spectroscopy, reflectance spectroscopy, and two-point probe resistivity measurement techniques were used to examine the optical, electrical, and dielectric properties of these films. Optical band gap energies of the PVP/GnP nano-composites were obtained using the most commonly used Tauc, Kubelka-Munk (K-M), Absorbance Spectrum Fitting (ASF), and Derivative (DM) methods. The results obtained by Tauc, K-M, and ASF methods were found to be consistent with each other. In addition, basic optical parameters such as Urbach energy (Eu), refractive index (n), optical conductivity (sigma opt) and dielectric constant (epsilon) of the PVP/GnP nanocomposites were investigated. As the GnP volume fraction increased in the nanocomposites, the electrical conductivity, Eu, n, sigma opt and epsilon increased whereas Eg decreased. These nanocomposites produced by varying the GnP volume fraction are promising for using optics, electricity, optoelectronics, and many other industrial applications.