Solution-Phase Synthesis of Single-Crystal CuO Nanoribbons and Nanorings

A solution-phase route has been developed for the synthesis of single-crystal CuO nanoribbons with widths of 10−80 nm, thicknesses of 5−20 nm, and lengths ranging from several hundred nanometers to several micrometers and for nanorings with diameters of 100−300 nm. The CuO nanoribbons and nanorings were fabricated by the reaction of CuCl₂ and NaOH solutions with sodium dodecyl benzenesulfonate (SDBS). The as-synthesized products were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM), revealing that CuO nanoribbons and nanorings had single-crystal monoclinic structures and nanorings were closed but were not the simple superposition of two ends of the nanoribbons. On the basis of TEM observations, the formation processes of nanoribbons and nanorings can be interpreted by two stages:  initial nanoflakes split into nanoribbons due to the Brownian movement of surfactant molecules, and then these nanoribbons that possess polar surfaces coil into nanorings to reduce the electrostatic energy. This ringlike CuO nanomaterial may have some potential value in nanoscale applications.