thioacetamide and cadmium-sulfide

CdMoO4@CdS core-shell hollow microspheres with the diameter of 2-3 μm were synthesized through a simple ion exchange hydrothermal method by using CdMoO4 solid microspheres as the sacrificial template in the presence of thioacetamide (TAA). Based on the detailed investigation it was found that the concentration of TAA in the starting solution affects the size of the CdS nanosheets and the hollowing process. At the TAA concentration of 0.1 M, CdMoO4@CdS core-shell hollow spheres with a CdS nanosheet thickness of 50-100 nm were obtained. The formed CdS nanosheets have a hexagonal wurtzite structure and exhibit good size uniformity and regularity. Furthermore, the photocatalytic activity of the as-prepared samples was evaluated towards degradation of Rhodomine B (RhB) aqueous dye solution under visible-light. Compared to CdMoO4 microspheres, CdMoO4@CdS core-shell hollow microspheres show enhanced photocatalytic activity. The observed photocatalytic performance was attributed to the synergetic effects of composite morphology, pore structure, and exposed two-dimensional (2D) CdS nanosheets with dominant 001 facets in CdMoO4@CdS core-shell hollow microspheres. Furthermore, the growth mechanism of CdMoO4@CdS hollow microspheres was discussed in detail.

Topics: Cadmium Compounds; Catalysis; Electrochemical Techniques; Light; Microscopy, Electron, Scanning; Microspheres; Photoelectron Spectroscopy; Sulfides; Thioacetamide

Thioacetamide (TAA) has served as an excellent sulfur source to react with cadmium stearate to controllably produce highly luminescent and monodisperse CdS nanocrystals through the hot-injection method in dodecylamine solvent. The kinetics and thermodynamics of nucleation/growth of CdS nanocrystals, as well as their optical properties are controlled by changing synthesis conditions such as reaction time, injection/growth temperatures, TAA concentration and cadmium source with different reactivity. Temperature-dependent release of reactive sulfur species from TAA, together with proper reactivity of cadmium source, facilitates the better separation of nucleation and growth stage, the formation of highly monodisperse CdS nanocrystals with tunable size and further self-assembly into ordered superlattices. When cadmium carboxylates such as cadmium stearate and cadmium oleate are used as cadmium sources, surface trap emission of CdS nanocrystals can be gradually removed to obtain bright pure-blue emission with increasing reaction time. The highest quantum efficiency of up to 33.6% is achieved when using cadmium stearate as cadmium source at the injection/growth temperatures of 230/210 degrees C for 90min.

Topics: Cadmium Compounds; Luminescence; Nanoparticles; Sulfides; Thioacetamide

A very fast, electroless, microwave method is described to synthesize electrically conductive CdS nanowires on DNA just within 60 s. The electrical characterization indicates that the CdS wires are continuous, have very low contact resistance, and exhibit Ohmic behavior. Highly selective deposition on DNA is obtained by specific complexation between the Cd(II) ion and DNA, followed by decomposition of thioacetamide to S(2-) to form CdS. The nanowires are found to have a diameter of 140-170 nm and a length of approximately 8-12 microm. The one-step process developed here does not perturb the overall conformation of the DNA chain. The nanowires we fabricated can be used as building blocks for functional nanodevices, tiny computers, sensors, and optoelectronics.

Topics: Cadmium Compounds; Costs and Cost Analysis; DNA; Electric Conductivity; Heating; Microscopy, Electron, Scanning; Microscopy, Electron, Transmission; Microwaves; Nanowires; Perchlorates; Spectrophotometry, Ultraviolet; Sulfides; Thioacetamide; Time Factors; Water; X-Ray Diffraction

A variety of nearly monodisperse semiconductor nanocrystals, such as CdS, ZnS, and ZnS:Mn, with controllable aspect ratios have been successfully prepared through a facile synthetic process. These as-prepared nanocrystals were obtained from the reactions between metal ions and thioacetamide by employing octadecylamine or oleylamine as the surfactants. The effects of reaction temperature and time, ratios of thioacetamide to inorganic precursors, and the reactant content on the size and crystal purity of the nanorods, have been systematically investigated. The optical properties and the formation mechanism of the nanorods have also been discussed. For the next biolabel applications, these hydrophobic nanocrystals have also been transferred into hydrophilic colloidal spheres by means of an emulsion-based bottom-up self-assembly approach.

Topics: Cadmium Compounds; Cations; Hydrophobic and Hydrophilic Interactions; Luminescence; Manganese; Microscopy, Electron, Transmission; Nanotechnology; Nanotubes; Particle Size; Semiconductors; Solvents; Spectrometry, Fluorescence; Sulfides; Surface-Active Agents; Temperature; Thioacetamide; X-Ray Diffraction; Zinc Compounds