▎ 摘　　要

In this current study, a set of five polymer-based graphene (PBG) thin films were prepared using polymer-in-polymer composite (70%PVP/30%PVA) doping with different concentrations of graphene (G) nanopowder, where a traditional preparation method was followed. The structures of the proposed graphene-doped PVA/PVP (PBG) polymeric composite films were characterized using XRD and FT-IR measurements, and the optical parameters were obtained using UV-Vis spectral analysis. The XRD patterns confirmed the amorphous phases of the synthesized PBG films with the existence of a semi-crystalline peak. The crystallinity degree was found to decrease when the graphene content was increased. The FT-IR spectra showed the characteristic features of both PVP and PVA polymers. The increase in the graphene content impacted the intensities of the vibrations of OH and C=O functional groups. When the graphene content was increased, the optical absorbance of the PVA/PVP composite increased with a decrease in the values of the direct and indirect optical energy bandgaps of the proposed polymeric films. Furthermore, the optical limiting (OL) effects decreased when increasing the weight concentration of graphene nanoparticles in the host blend polymer. The OL findings suggested that G-rich films could be used to protect optical sensors and human eyes from intense laser beams. The AC conductivities of the graphene-doped PVA/PVP polymeric composites increased linearly when the frequency of the applied field increased. The measured AC electrical conductivity was fitted using many theoretical approaches, where the correlated barrier hopping CBH model gives the best fit. Accordingly, the conduction mechanism has been assigned to the correlated hopping over the potential barriers. The as-synthesized graphene-doped PVA/PVP polymeric composite films with remarkable optical and electrical properties would be outstanding candidates for optoelectronic, laser limiter, optical filter, and biomedical laser applications.