Synthesis and characterization of cuprous sulfide crystals with novel morphology

Cuprous sulfide (Cu2−xS) crystals in different stoichiometries were synthesized by hydro- and solvo-thermal methods at 125 °C using Na2S2O3 as sulfur source in pure water, mixed solvents of ethylenediamine (en) and water, and pure en, respectively. The products were characterized by X-ray powder diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersion spectrometer (EDS), transmission electron microscope (TEM) and selected area electronic diffraction (SAED). Owing to different sulfur sources, crystal structures and morphologies of cuprous sulfides were different from those developed by some former researchers. Novel twelve-fold symmetrical Cu7S4 single crystals were synthesized at an en/water volume ratio of 3:1, and they were built up by two layers of about 80–100 nm in thickness. Moreover, the possible growth process had been discussed based on the analyses of detailed configuration of the products.