Surfactant-free fabrication of Cu2O nanosheets from Cu colloids and their tunable optical properties

Novel sheetlike Cu2O two-dimensional (2D) nanoarchitectures were successfully synthesized via a copper nanoparticle-mediated process for the first time. Uniform and nearly monodisperse Cu nanocolloids were firstly synthesized by disproportionating reaction of Cu+ at the surfactant-free ambient conditions, and Cu2O nanosheets were subsequently synthesized by choosing ethanol solvent agent to limit the oxidized processes of Cu nanocolloids. The synthesized products were systematically studied by X-ray powder diffraction, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV–vis absorption spectra. It was demonstrated that the solvent agent of ethanol played key roles in the formation of the as-synthesized nanosheets. By choosing the different solvent agents to limit the oxidized processes, Cu2O nanospheres and nanocubes can be selectively synthesized accordingly.