Facile synthesis and optical characterization of graphene oxide-doped TiO₂/polyvinyl alcohol nanocomposites: Optical limiting applications

In this present research, PVA polymer was utilized as a host polymer to fabricate free-standing PVA/TiO₂: GO nanocomposites films. The fabricated films were subjected to different structural inspections; at first the surface topography was examined by scan electron microscopy, SEM. The analyzed PVA/TiO₂ doped 30 ml graphene oxide film revealed in most a smoothed surface without any microcracks or physical and/or chemical treatment (as a representative sample). Secondly, The crystal structure of the fabricated samples (PVA/TiO₂:doped GO) was analyzed through its recorded XRD patterns. At normal incidence, spectrophotometric properties such as: transmittance, Reflectance and absorbance, Abs were characterized to estimate the Optical constants such as refractive index (n) and extinction coefficient (k) for the fabricated samples. The linear and nonlinear propagation of probe normal light beam in PVA/TiO₂: GO nanocomposites were inspected and elucidated in wavelength from 250 to 2500 nm. The estimated values of the oscillator energy and strength are increased with the doping ratio from 0 to 40 ml. The calculated value of the group velocity is less (c = 3 × 10⁸ m sec^-1) and decreases with increasing of the GO-doping ratio. The extracted value of static refractive index and direct energy gap was found to be decreased from 5.42 to 1.22 and from 2.12 to 1.49 as GO-doping ratio was increased from 0 to 40 ml GO, respectively. The evaluated Attenuation power of the fabricated free-standing PVA/TiO₂: GO samples elucidated that the optical limiting results studies showed that it may be suitable to attenuate the laser power by utilizing the fabricated PVA/TiO₂: GO films.