One-step synthesis of metal sulfide/tellurium composites with distinct microstructures

Microsphere flower- and mushroom-shaped metal sulfide/tellurium composites were synthesized through a one-step and template-free approach in which the simultaneous formation of tellurium and NiS (or CdS) leads to well-dispersed composites. The development of such distinct microstructures has been systematically investigated as a function of reaction temperature, concentrations of the starting reagents, and reaction time. Characterizations with scanning and transmitting electron microscopy, energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and thermal gravimetric methods illustrate that the as-obtained metal sulfides exist in different phases in the composites. CdS was found to present as cubic sphalerite-type cadmium sulfide crystals, whereas NiS was in the amorphous form. Photo-excitation and emission property of the NiS/Te composite was also examined. (author)