Gamma irradiation boosted the optical and electrical properties of PVP/NaAlg/Au ternary nanocomposite films for flexible optoelectronic devices

Gold nanoparticles (Au NPs) were successfully biosynthesized using the extract Chenopodium murale leaves in a cooperative manner. Au NPs of weight percentage (0.38 wt%) were incorporated into the polymeric blend of polyvinyl pyrrolidone and sodium alginate (PVP/NaAlg) by the solution casting procedure. The prepared polymer nanocomposite sample was exposed to gamma irradiation with various doses (2, 4 and 6 Mrad). The FT-IR spectra indicated the functional groups of blend components (PVP and NaAlg) that interacted through the formation of hydrogen bonding. The amorphous character of PVP/NaAlg was confirmed by XRD technique, which was largely increased by both the incorporation of Au NP and the subsequent doses of radiation. Also, these functional groups were affected due to the processes of Au NPs and irradiation. The UV/vis spectra indicated the presence of Au NPs within the nanocomposite sample by showing the characterized surface plasmon resonance peak at 539 nm. The absorbance of this peak was enhanced, and its position is blue-shifted after the gamma irradiation reflecting the narrow size distribution and the production of smaller Au NPs. Also, the values of optical band gap, refractive index and Urbach energy were calculated. The TEM images showed the spherical morphology of Au NPs, and their sizes were decreased due to the irradiation effects such as chain scission and cross-linking reactions. SEM images showed the dispersion of Au NPs on the surface of the nanocomposite/6 Mrad sample, where the aggregations of Au NPs were decreased. The electrical conductivity and dielectric parameters values of PVP/NaAlg blend were improved as a result of Au NPs addition and gamma irradiation, where these values largely depended on the irradiation dose. Such promising features of irradiated PVP/NaAlg-Au nanocomposite samples depict their appropriateness in the development of the next generation of advanced optoelectronic devices, optical sensors, tunable-flexible nanodielectrics for microelectronic devices, porous membrane technology.