Structural and Optical Characterization of ZnO-Graphene Nanocomposite Quantum Dots

In this research, zinc oxide quantum dots and graphene nanocomposites were synthesized via two different methods; In the first (direct) method, ZnO-graphene Nanocomposites were made mixing the synthesized zinc oxide and graphene. In the second (indirect) method, zinc nitrate, graphene, and sodium hydroxide were used to made ZnO-graphene Nanocomposites. XRD, FTIR and Raman spectroscopy analyses were used for phase and structural evaluations. The morphology of the nanocomposites w::as char::acterized by SEM. The specific surface area and porosity of the samples were characterized by BET analysis. The optical properties of the samples were investigated by photoluminescence and ultraviolet-visible spectroscopy analyses. Results showed that using graphene, increased the photoluminescence property and shifted the photoluminescence spectrum of the composites towards the visible light spectrum. The photoluminescence of the synthesized graphene-zinc oxide composite, in the visible light region, was closer to white light than that of pure zinc oxide. According to the results of BET test, the nanocomposite synthesized by direct method had a higher surface area (25.7 m2.g-1) and a higher porosity (0.32 cm3.g-1) than the nanocomposite synthesized by the indirect method with a specific surface area of (16.5 m2.g-1) and a porosity of 0.23 cm3.g-1).