Ternary metal sulphide nanocrystals in MCM-41 nanoparticles matrix: preparation and properties

The optical and structural properties of the ternary ZnCdS nanocrystals in MCM-41 are reported. The samples were obtained by sulfidation of the Zn²⁺ and Cd²⁺ ion-exchange zeolite in a Na₂S solution at room temperature. The final products (ZnCdS-MCM-41) were characterised by X-ray diffraction (XRD) pattern, scanning electron microscopy (SEM), transmission electron microscopy, infrared spectrometry and UV-vis spectroscopy. Their crystalline structure and morphology were studied by XRD and SEM. Exciton absorption peaks at higher energy than the fundamental absorption edge of bulk ZnS indicate quantum confinement effects in nanoparticles as a consequence of their small size. The absorption spectra show that the optical bandgap varies in the range 2.5-3.6-eV, depending on the semiconductor material and their relative concentration.