Enhancing the Optical Properties of Starch/ZnO Nanocomposite Using Graphene Oxide

Due to its biocompatibility, starch is an eco-friendly polymer for various applications, from medical applications to optoelectronic ones. Polymer nanocomposites based on starch, zinc oxide nanoparticles (ZnO NPs), and graphene oxide (GO) are synthesized using a casting technique. A UV-Vis spectrophotometer studied optical properties, and the nanocomposite molecular structure was determined using a Fourier transform infrared (FTIR) spectrometer. The starch absorption edge was shifted to the lower energy region, and it was found that starch has two absorption edges and hence two optical band gaps. The direct and indirect optical band gap values were determined for pure starch, starch/ZnO, and starch/GO nanocomposites. Incorporating 6wt.% of ZnO NPs reduces the indirect optical bandgap from 4.77 to 2.88 eV. Meanwhile, incorporating 2wt.% of GO reduced the bandgap to 2.15 eV.