Synthesis and optical properties of CuO nanostructures in imidazolium-based ionic liquids

Cupric oxide (CuO) nanostructures having different morphologies such as needle like leaf, nanowire, cluster-like and microbundle of nanorods have been successfully synthesized via an environment-friendly ionothermal method using ionic liquids [BMIM]Br and [OMIM]Br in different temperatures at ambient pressure. The structure and the optical properties of the these CuO particles are investigated by using X-ray diffraction (XRD), scanning electron microscopy (SEM), and UV-visible absorption spectroscopy. The results indicate that ionic liquids and temperature play an important role in size and morphology of the CuO nanostructures. A possible mechanism was proposed to explain the formation of CuO nanostructures with different morphologies. The band gaps are estimated to be 1.57-1.75 eV according to the results of the optical measurements of the CuO nanostructures. (C) 2013 Elsevier B.V. All rights reserved.