ABSTRACT
This study reports the structural and optical properties of CdS/ZnTiO3 nanocomposites prepared using a chemical bath and different titanate concentrations. Commercial ZnTiO3 nanoparticles were introduced into a chemical bath that had been used to produce CdS semiconductor nanoparticles (NPs). Here, the growing CdS crystallites precipitated onto the suspended zinc titanate NPs. X-ray diffraction patterns revealed that samples of CdS/ZnTiO3 nanopowders were made of cubic ZnTiO3 and hexagonal CdS wurtzite. The morphology of the particles was studied using transmission electron microscopy and scanning electron microscopy images. These images demonstrated the different characteristics of the CdS/ZnTiO3 nanocomposites and their dependence on titanate concentration when placed into the CdS-growing solution. Photoluminescence spectra showed three main emission bands for the electron transitions in the CdS/ZnTiO3 composite. This composite produced three photoluminescence bands, the intensities of which depended on composite shape, which in turn depended on the relative concentrations of CdS and ZnTiO3 .
Subject(s)
Cadmium Compounds/chemistry , Luminescent Measurements , Nanostructures/chemistry , Oxides/chemistry , Sulfides/chemistry , Titanium/chemistry , Zinc/chemistry , Particle Size , Photochemical Processes , Porosity , Semiconductors , Surface PropertiesABSTRACT
The aim of this research was to synthesis biocompatible iron disulphide nanocrystals at different reaction temperatures using the colloidal synthesis methodology. Synthesis was conducted at the 220-240 °C range of reaction temperatures at intervals of 5 °C in an inert argon atmosphere. The toxicity of iron disulphide nanocrystals was evaluated in vitro using mouse fibroblast cell line. Two complementary assays were conducted: the first to evaluate cell viability of the fibroblast via an MTT assay and the second to determine the preservation of fibroblast nuclei integrity through DAPI staining, which labels nuclear DNA in fluorescence microscopes. Through TEM and HRTEM, we observed a cubic morphology of pyrite iron disulphide nanocrystals ranging in sizes 25-50 nm (225 °C), 50-70 nm (230 °C) and >70 nm (235 °C). Through X-ray diffraction, we observed a mixture of pyrite and pyrrohotite in the samples synthesized at 225 °C and 240 °C, showing the best photocatalytic activity at 80% and 65%, respectively, for the degradation of methylene blue after 120 minutes. In all experimental groups, iron disulphide nanocrystals were biocompatible, i.e. no statistically significant differences were observed between experimental groups as shown in a one-way ANOVA and Tukey's test. Based on all of these results, we recommend non-cytotoxic semiconductor iron sulphide nanocrystals for biomedical applications.
