Abstract:

In the present work, flower-like CuO nanostructures were synthesized by reflux condensation method without using any surfactants or templates. Structural analysis by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Raman studies revealed the formation of highly crystalline single phase CuO, exhibiting monoclinic structure. Morphological analysis by field emission scanning electron microscopy (FESEM) showed flower-shaped CuO hierarchical architecture made up of interpenetrating self-assembled nanosheets. Optical analysis by UV–Vis diffused reflectance spectra (DRS) exhibited considerable blue-shift in the optical band gap due to quantum confinement effect. Photoluminescence (PL) spectrum showed both UV as well as visible emissions. The antibacterial activity of flower-shaped CuO nanostructures were tested against gram-positive (Bacillus subtilis, Bacillus thuringiensis) and gram-negative (Salmonella paratyphi, Salmonella paratyphi-a, Salmonella paratyphi-b, Escherichia coli and Pseudomonas aeruginosa) bacteria. Also, the antifungal activity of CuO was investigated against Aspergillus niger, Rhizopus oryzae, Aspergillus flavus, Cladosporium carrionii, Mucor, Penicillium notatum and Alternaria alternata. Results demonstrate that the flower-shaped CuO nanostructures act as an effective antimicrobial agent against pathogenic bacteria and fungi.

Key words: CuO nanosheets, Hierarchical, X-ray diffraction, Photoluminescence, Antibacterial, Antifungal