Investigations on synthesis, characterization and humidity sensing properties of ZnO and ZnO-ZrO composite nanoparticles prepared by ultrasonic assisted wet chemical method.

In the present investigations, Zinc oxide (ZnO) and ZnO-ZrO composite nanoparticles were synthesized by ultrasonic assisted wet chemical method to investigate their structural, optical and humidity sensing properties. The synthesized nanoparticles were characterized by the techniques like X ray diffraction (XRD), UV-Vis absorption spectroscopy, Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS). XRD and EDS were employed to confirm the phase formation and phase purity respectively. SEM micrographs showed that morphology of the parent compound ZnO is considerably changed with varying concentration of ZrO. The optical absorption spectra showed that optical absorption of ZnO decreases with increase in ZrO content in the composite. The observed band gap values for ZnO and ZnO-ZrO composites were higher as compared to the bulk sample. The humidity sensing performance was substantiated for all the samples and the result of effect of concentration of ZrO in ZnO-ZrO composites on sensitivity, response and recovery time are discussed in detail.