Effect of PO Content on Luminescence of Reduced Graphene-Oxide-Doped ZnO-PO Nano-Structured Films Prepared via the Sol-Gel Method.

A convenient and low-cost sol-gel approach for the one-step synthesis of ZnO-PO-rGO nanostructures with tuned bandgap and fluorescence was investigated. The obtained hybrid nanostructures exploit the properties of zinc oxide, graphene oxide and phosphorous oxide as promising candidates for a wide range of optoelectronic applications. A predominant amorphous structure, ZnO-PO-rGO, containing ZnO nanorods was evidenced by X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM). The estimated size of the ZnO nanorods in nanostructures with PO was noticed to decrease when the PO/ZnO ratio was increased. The presence of ZnO, PO and rGO was confirmed by Fourier-transform infrared spectroscopy (FTIR) and Raman investigation. PO was noticed to tune the bandgap and the fluorescence emissions of the nanostructured films, as estimated by UV-Vis-NIR and fluorescence spectroscopy, respectively. The electrical measurements performed at room temperature showed that the main influence on the film's resistivity does not come from the 1% rGO doping but from the PO/ZnO ratio. It was found that a 10/90 molar ratio of PO/ZnO decreases the resistivity almost seven-fold compared with rGO-doped ZnO films.