Facile synthesis of graphene oxide/PVA nanocomposites for laser optical limiting: band gap analysis and dielectric constants

Casting technique was used to prepare nanocomposites of polyvinyl alcohol (PVA) and graphene oxide (GO). GO has been set up by Hummer's method and characterized by SEM and X-ray spectroscopy. Samples have been designed to contain a different weight percent of GO as follows: (0.370, 0.926, 1.852, 2.778, 3.704, 9.259 wt%) inside PVA matrix under the homogenous ultrasonic system to have a highly dispersed GO in PVA matrix. The nanocomposites were described and analyzed by utilizing different methods such as UV-Vis-NIR, dielectric studies at room temperature and optical limiting properties. It is shown that the influence of the nanofiller leads to the increase in the absorption values while diminishing the optical band gap of both direct and indirect transition. The dielectric constant (epsilon') and the dielectric loss (epsilon aEuro(3)) were studied within the frequency range from 3 kHz to 10 MHz and were found to be depending on the GO contents. The conduction mechanism for the studied samples can be described by the correlated barrier hopping. PVA/GO nanocomposites showed good optical limiting properties. The synthesized GO-doped PAV can be used in electronic and optoelectronic applications especially in battery electrolyte and dye-sensitized solar cells.