Synthesis and characterization of CdS nanoparticles prepared by precipitation in the presence of span 20 as surfactant

Abstract

Cadmium sulfide nanoparticles with average size of ≈16 nm have been synthesized using chemical precipitation reaction of CdCl₂ and Na₂S in the presence of nonionic surfactant stabilized reverse emulsions. Sorbian monolaurate (Span 20) is used for the stabilization of emulsions. The influence of Span 20 on controlling the size and properties of CdS nanoparticles were studied. The obtained CdS nanoparticles were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Energy-dispersive x-ray (EDX), and X-ray diffraction (XRD). The optical properties of CdS nanoparticles are investigated systematically by UV-visible absorption spectroscopy. The blue shift in the absorption region and increase in the bandgap to the larger value (2.77 eV) are attributed to the nanosize of the obtained particles.