Synthesis, structural and optical characterisation of cadmium sulphide nanoparticles

Cadmium sulphide nanoparticles of uniform size have been synthesized at room temperature via wet chemical precipitation method using cadmium chloride and sodium sulphide with methanol as capping agent. The microstructure and morphology of the synthesized CdS nanoparticles have been characterized by X-ray diffraction and scanning electron microscopy analysis. XRD pattern reveals that as-synthesized CdS nanoparticles exhibit both sphalerite and wurtzite phases. The size of the particles calculated by Debye Scherrer formula according to the XRD spectra has been found to be about 13-17 nm. X-ray peak broadening analysis has been used to calculate the crystalline size and lattice strain by the Williamson-Hall (W-H) plot. The optical properties of the sample have been studied by UV-Visible and photoluminescence spectroscopy. The existence of blue shift in UV-visible spectroscopy reveals the quantum confinement effect of CdS nanoparticles. The photoluminescence spectrum shows two broad bands centered at 422 and 538 nm.