Structural, optical and antimicrobial characteristics of ZnO green nanoparticles

In this paper, we exploit the sol-gel method to synthesize zinc oxide green nanoparticles (ZnO-GNPs) with different concentrations of zinc acetate dehydrate [Zn(Ac)(2)-2H(2)O] such as 1, 5, 7, and 9 % using Aloe-Vera extracts. The Rietveld refinement analysis of X-rays diffraction (XRD) patterns of ZnO-GNPs reveals the hexagonal unit cell structure with the space group P63mc. Scanning electron microscope (SEM) characterization exhibits that size of the particles increases with increasing concentration of Zn(Ac)(2)-2H(2)O. The PL spectra show an excitonic emission and oxygen defects at room temperature. The bandgap of ZnO-GNPs increases with increasing Zn (Ac)(2)-2H(2)O concentration. The Raman spectra show strong E-2 (H) vibrational mode along with A(l) (TO) and E-1(LO) Raman modes. The ZnO-GNPs demonstrate a strong antibacterial activity against Gram-positive (Staphylococcus aureus), ranging from 32 to 42 nm, and Gram-negative bacteria (Escherichia coli) in the range of 30-34 nm. These results suggest a potential use of green-synthesized ZnO-GNPs, being more eco-friendly than those synthesized by the chemical route, as an antimicrobial agent against drug-resistant microbes. [GRAPHICS] .