Synthesis of Nanocrystalline Cobalt Selenide in Nonaqueous Solvent

Cobalt selenide nanocrystals have been synthesized by a solvothermal reaction between metallic cobalt and selenium at 140°C. The products obtained have been characterized by X-ray powder diffraction (XRD) and transmission electron microscopy (TEM). According to the XRD analysis, the as-produced cobalt selenide adopted a NiAs structure analogous to that of Ni0.85As. Therefore, it was termed Co0.85Se. Elemental analysis showed a cation-deficient composition of about Co0.844Se. TEM observation indicated that the obtained Co0.85Se nanocrystals were of foliate morphology. IR analysis suggested that the product was free from contaminants such as ethylenediamine. The influence of various solvents on this synthetic process has been discussed. Ni0.85As has also been synthesized with a similar synthetic process.