Structural, morphological, optical and biomedical applications of Berberis aristata mediated ZnO and Ag-ZnO nanoparticles

Herein, we prepared the zinc oxide (ZnO) and silver doped zinc oxide (Ag-ZnO) nanoparticles (NPs) using Berberis aristata plant extract as a reducing, capping and stabilizing agent. The x-ray diffraction (XRD) pattern confirms the formation of pure hexagonal wurtzite structure for both the samples with P4mm space group. The crystallite size reduces from 21.313 nm to 18.179 nm with the Scherrer technique with doping of Ag ions on ZnO NPs, while the Williamson Hall (WH) approach likewise demonstrates a decrease in crystallite size from 26.602 nm to 21.522 nm. The lattice strain increases from 0.0031 to 0.0064, indicating the presence of Ag-ions in the crystal lattice of ZnO NPs. For both samples, the metal-oxygen bond formation is supported by the Fourier Transform Infrared (FTIR) spectra. For ZnO, the peak in the UV-visible spectrum is approximately around 365 nm, but for Ag-ZnO, two peaks are observed around 235 nm and 360 nm. With the Ag doping, the bandgap increases from 3.01 eV to 3.02 eV. Transmission Electron Microscopy (TEM) micrographs show the formation of crystalline particles and Field Emission Scanning Electron Microscopy (FESEM) pictures show the formation of aggregated NPs with a spherical shape. Energy Dispersive x-ray Spectroscopy (EDX) and x-ray Photoelectron Spectroscopy (XPS) demonstrate the chemical purity of both the samples. The antibacterial activity of ZnO NPs was highest against Staphylococcus aureus i.e., 15 ± 0.53 mm, whereas, for Ag-ZnO NPs the highest activity was against Salmonella typhi i.e., 19 ± 0.53 mm.