Formation of various morphologies of covellite copper sulfide submicron crystals by a hydrothermal method without surfactant

Covellite copper sulfide submicron crystals in the shapes of ball-like, rodlike, and chrysanthemum-like architectures congregated from nanoslices with thickness of 20 to 100 nm have been prepared by a hydrothermal method without using any surfactant and characterized by X-ray diffraction, energy-dispersive X-ray spectrometer (EDX), UV-vis optical absorption spectra, and electron-microscopy techniques. A systematic investigation has been carried out to understand the factors influencing the evolution of the crystal morphology which was found to be predominant by the reactant molar ratio (Tu:Cu(NO3)(2), Tu = thiourea), the hydrothermal reaction time, and the temperature. Possible crystal growth processes are also discussed.