Morphological evolution of ZnO nanostructures with hydrothermal oxidation time and their electrochemical glucose sensing properties

In this work, zinc oxide (ZnO) nanostructures have been grown from electrodeposited Zn thin film followed by hydrothermal oxidation. The Zn layer was grown on copper (Cu) substrate at room temperature and then oxidized hydrothermally at 95 degrees C for different time duration. X-ray diffraction (XRD) patterns depicted that Zn thin film transformation to ZnO started after 1 h of oxidation and almost completed after 24 h. SEM results show the morphological transformation from Zn thin film to ZnO nanostructures by varying hydrothermal oxidation time duration. The influence of this morphological transformation on the photoluminescence (PL) spectra and non-enzymatic glucose sensing has been investigated. The full width half maximum (FWHM) of the UV emission peak in PL spectra became narrow with an increase in oxidation time. The electrochemical glucose sensing measurements show that the current density rises with an increase in oxidation time. The maximum current density has been observed for ZnO nanostructure oxidized for 24 h.