Preparation of CdS Nanoparticles from Thiosemicarbazone Complexes: Morphological Influence of Chlorido and Iodido Ligands

Cadmium(II) thiosemicarbazone complexes were prepared and characterized by elemental analysis and IR and NMR spectroscopy. The complexes were then investigated as potential single-source precursors for the synthesis of oleylamine-capped cadmium sulfide nanoparticles by solvothermal decomposition. The resulting nanomaterials were characterized by powder XRD, TEM, HRTEM, energy-dispersive X-ray analysis, and UV/Vis spectroscopy. Peak broadening in the XRD patterns confirmed the presence of relatively small hexagonal CdS nanocrystals. The TEM studies evidenced that the chlorido precursors produced CdS nanostructures whose morphologies differed from those obtained from the iodido precursors. CdS nanoparticles in the form of cubes/spheres/rods and nanodendrite structures were obtained from CdCl2 and CdI2 thiosemicarbazone complexes, respectively. The UV/Vis spectra revealed that the as-synthesized CdS nanoparticles exhibited a quantum effect due to their sharp band edges, which are blueshifted relative to those of bulk CdS. The size, morphology and shape of the nanoparticles were also shown to depend on the temperature of formation.