Facile synthesis and phase control of copper chalcogenides with different morphologies

A series of stoichiometric and nonstoichiometric copper-chalcogenide nanocrystallines with different morphologies, e.g., extremely high aspect ratio nanofibers (Cu9S8), tubular structure (Cu (x) S (x=similar to 1.86-1.96), nanorods (CuS, Cu31S16), platelets (beta-CuSe, Cu3Se2), rope-like Cu3Se2, as well as spherical nanoparticles (Cu7Se4, Cu2-x Se), have been successfully synthesized in 20 vol% water and 80 vol% organic solvents mixture under mild conditions. The products were characterized by various techniques, including X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), electronic diffraction (ED), and high-resolution transmission electron microscopy (HRTEM). The studies of the optical properties revealed that the copper chalcogenides have a wide absorption in the range of about 400-700 nm, with accessional IR band. Systematic studies showed that the mixture of 20 vol% water and 80 vol% organic solvents played a key role in controlling the copper chalcogenides with different morphologies and phases.