Abstract
AbstractPolymer matrices prevent semiconductor nanoparticles of CdS and ZnS from photooxidation and are benefit to immobilization of nanoparticles. Since the particles size of nanoparticles can be controlled efficiently by using the reverse micellar solution systems, such as water/AOT/isooctane micro- emulsion system, we prepare the semiconductor-polymer nanocomposites in reverse micellar solutions containing polymerizable surfactants.The particle size can be controlled by adjusting the water ratio (Wo) in the reverse micelles. The particle size of CdS ranges from 4.0nm to 6.2nm when the Wo adjusted from 0.5 to 2.5. The onset of the UV-Vis absorption spectrum is blue-shifted with particle sizes due to the quantum size confinement.We varied the parameter x (x=[Zn2+]/[Zn2+]+[Cd2+]) to discuss the characteristics of mixed CdS-ZnS, coprecipitated Zn(x)Cd(1-x)S, CdS/ZnS and ZnS/CdS core-shell nanoparticles with UV-Vis and PL spectra. The PL intensity of CdS/ZnS nanoparticles is the greatest among them because ZnS shell can provide a surface passivation for CdS core. Therefore, ZnS removes the non-radiative recombination and the electrons and holes on the surface of CdS will be prevented from undergoing redox processes with absorbed chemical species.In addition, we employed DLS, SEM and SAXS to measure the particle size which is under 10nm. And by using poly core-shell scattering intensity to fit SAXS data, we obtained the shell thickness of CdS/ZnS(x=0.75) to be 3.6A.Also, from the UV-Vis spectrum and SEM composition mapping, we can obtain some information about the resulting nanocomposite. The CdS/ZnS nanoparticle can be maintained and dispersed very well in the PCV matrix, and may find applications in optical devices.