Effect of Structural, Optical, and Antibacterial Properties of Various Zinc Oxide Morphologies

Abstract

This study investigates the influence of different zinc oxide morphologies on their structural, optical, and antibacterial properties. These investigations have extensive antibacterial capabilities of zinc oxide (ZnO) nanostructures, effectively targeting various microorganisms prevalent in environmental settings, including soil, water, and food. The synthesis of ZnO nanostructures was conducted through a hydrothermal method, varying the pH from 8 to 12, using zinc chloride (ZnCl) and sodium hydroxide (NaOH) as precursors, and subjected to the 24-hour heating process at 180°C. The characterisation of the samples involved X-ray diffraction (XRD), Ultraviolet-Visible (UV-Vis) spectroscopy, and inhibition zones in Escherichia coli (E. coli) agar plates. The XRD pattern illustrated the hexagonal wurtzite structure of the ZnO nanostructure, with the average crystallite size calculated. UV-Vis spectroscopy indicated absorption peaks of ZnO around 300 to 400 nm, signifying a blue shift. Furthermore, optical band gaps, derived from UV spectroscopy, demonstrated an increment from 2.88 to 3.25 eV across all samples. The size of the inhibitions zone increased as the pH values of ZnO increased. ZnO shows increased inhibition zones with higher pH, hexagonal wurtzite structure, and increasing optical band gaps. The relationship between zinc oxide morphologies and their structural, optical, and antibacterial properties offers the development of ZnO-based materials with enhanced performance for biomedical, pharmaceutical, and environmental applications.