Synthesis and Spectral Studies of Ni(II) Dithiocarbamate Complexes and Their Use as Precursors for Nickel Sulphides Nanocrystals

Ni(II) dithiocarbamate complexes have been synthesized and characterized by UV-Vis, FTIR, and NMR spectroscopic techniques. Electronic spectra measurements indicate that the complexes are four-coordinate square planar geometry while the FTIR confirmed that the dithiocarbamates act as bidentate chelating ligands. The compounds were used as single source precursors and thermolysed at 220 degrees C to prepare HDA-capped NiS nanocrystals which were characterized by absorption and photoluminescence (PL) spectra measurements, powder X-ray diffraction (PXRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). Absorption spectra studies showed that the synthesized NiS nanoparticles are blue-shifted relative to the bulk material and PL studies showed emission maxima that are red-shifted compared to the absorption band edges. The XRD patterns of the as-prepared NiS nanoparticles revealed cubic crystalline phases. TEM images showed spherical and close-to-spherical nanocrystals with the size in the range 12-38 nm for NiS1, 8-11 nm for NiS2, and 9-16 nm for NiS3. SEM images showed homogeneous surface morphology and EDS confirmed the presence of Ni and S and the formation of NiS nanoparticles.