One-pot synthesis of multifunctional ZnO nanomaterials: study of superhydrophobicity and UV photosensing property

Abstract

ZnO nanomaterials are synthesized using one-pot synthesis method. Equimolar solution of Zinc Nitrate hexahydrate (Zn(NO3)2.6H2O) and Hexamethylenetetramine (C6H12N4) is used as a precursor for ZnO formation. Different nanostructures of ZnO are achieved by controlling the pH of the growth solution in the range 2–12 (acidic to alkali). ZnO nanostructures are evaluated for hydrophobic property using static contact angle measurement setup and UV photosensing activity. Surface morphology, structural properties and compositional analysis of ZnO nanostructures are examined by field emission scanning electron microscope (FE-SEM), energy dispersive X-ray analysis (EDX), high-resolution transmission electron microscope (FEG-TEM) and X-ray diffraction (XRD) measurements. Existence of ZnO wurtzite structure is confirmed from XRD study and is analyzed by Rietveld refinement method. Nanomaterials are characterized using Raman spectroscopy which confirms highest oxygen deficiency in ZnO nanorods. The material shows remarkable superhydrophobic and UV photosensing property and hence the name multifunctional. Among all morphologies grown at different pH values, ZnO nanorods show superhydrophobic nature with contact angle more than 170°. Total surface energy value of ZnO nanostructures is calculated using Wendt two-component theory. Different ZnO nanostructures (with variation of pH value) are used to study UV photosensing property. Responsivity and photocurrent show a strong dependence on the morphology of ZnO.