Synthesis, characterization, and nonlinear optical properties of hybridized CdS-polystyrene nanocomposites

Hybrid composites of CdS nanoparticles embedded in sulfonated polystyrene (PS) matrixes have been prepared and characterized. The -SO3 groups acted as the coordination sites for cadmium ion aggregations and nanosized CdS particles were successfully grown in situ at these sites with the release of S2- ions from thioacetamide. The density and size of the nanoparticles were found to be a function of the sulfonate content of PS and the concentration of Cd2+ feed ions used. Ionic clusterings within the polymer matrix occurred at a sulfonate content of 9.9 mol % and has provided a confined medium for particle growth in uniform size. The optical properties of the prepared CdS-PS hybrid composites were characterized by linear absorption and fluorescence spectra. Z-scan measurement was also employed to investigate the nonlinear optical properties at a wavelength of 532 nm. The results showed that the nonlinear refractive index of the composite varies with the input irradiance, thus indicating not just third-order but possible higher order nonlinearity.