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In this present work, the effects of coating of graphene oxide (GO) at different concentrations (0, 0.2, 0.3, 0.4, 0.5, and 0.6 mg/ml) onto zinc oxide (ZnO) nanostructured were investigated. ZnO and ZnO coated with GO (ZnO/GO) were prepared using immersion method. The structural, morphology and optical properties of all samples have been studied using x-ray diffraction (XRD), field emission scanning microscopy (FESEM) and UV Vis spectroscopy. The peak obtained from the XRD pattern shows that all samples are in the hexagonal-wurtzite structure. The (002) peak shows the strongest intensity for all samples with the highest (002) peak obtained for the ZnO/GO sample coated at a GO concentration of 0.5 mg/ml. The diameter of ZnO/GO nanostructured samples decreased after coating with GO at concentrations of 0.2 to 0.5 mg/ml and the diameter increased again when ZnO nanostructures were coated with GO at above 0.5 mg/ml. The highest transmission spectrum was obtained for the ZnO/GO sample coated with GO at a concentration of 0.5 mg/ml. In conclusion, the effect of GO coating on ZnO nanostructured can be changed at different concentrations of GO. The optimal properties of ZnO/GO may be suitable as a photoanode in DSSC applications.

The purpose of this study is to determine the effect of different graphene oxide (GO) solution immersion temperature on the structural, morphology, optical, and electrical properties of zinc oxide/graphene oxide (ZnO-GO) nanostructures. The ZnO/GO nanostructures prepared at various GO solution immersion temperature from 75-95℃ using solution immersion method. The structural properties of the samples were investigated using X-ray diffraction (XRD), and the recorded patterns revealed that all the samples had a preferred orientation along the (002) plane. The crystallinity of ZnO/GO nanostructures were enhanced with increasing GO solution immersion temperature. The morphology of ZnO/GO nanostructures was determined using field emission scanning electron microscopy (FESEM). Fourier transformation infrared spectroscopy (FTIR) was used to determine the molecular compounds of ZnO/GO nanostructures. The peak intensity of GO with ZnO nanoparticles is shifted at 744 to 1243 cm-1 when the temperature of GO solutions increases. The UV–visible spectrophotometer was used to examine the optical properties of ZnO/GO nanostructures. It is found that the highest transmittance ZnO/GO nanostructures was obtained at the highest GO solution immersion temperature which is 95℃. Based on the current-voltage(I–V) measurement, the electrical properties of ZnO/GO nanostructures increase when the GO solution immersion temperature increases. Thus, by variation of GO solution immersion temperature the structural, morphology, optical, and electrical behaviour were improved.

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The graphene sheets were aqueous processed via simple method liquid phase exfoliation. Sodium perylene-3, 4, 9, 10-tetracarboxylate (NaPTCA) were used as surfactant to assist the exfoliation process. The purpose of this research is to investigate the impact of NaPTCA concentration on the yield of liquid phase exfoliation of graphite to graphene sheets. The degree of exfoliation was found to be greatly influenced upon the concentration of NaPTCA surfactant. 1.0 mgmL-1 was identified as the optimal NaPTCA concentration as the graphene produced had a distinct x-ray diffraction crystallinity, scanning electron microscopic image features, high concentration of graphene dispersion (0.154 mgmL-1) and high conductivity values (751.88 Sm-1) in 2-probe electrical measurements, all of which comparison are much favourably with typical values obtained for multi-layer graphene. Hence, this simple approach for liquid-phase graphite exfoliation provides decent potential for mass production of high-quality graphene for a wide range of applications in energy storage, optical, and electronic areas.