CdS Nanoparticles: A Facile route to Size-Controlled Synthesis of Quantum Dots on a Polymer Matrix

An efficient route for fabrication of cadmium sulfide nanoparticles in polymer matrix is presented in this paper. CdS quantum dots have been prepared in polyvinyl alcohol (PVA) by SILAR method. The effect of cycle number on physical properties of CdS nanoparticles has been studied. The optical, structural and morphological properties of nanocrystal samples were characterized by Uv-Vis absorbance, X-Ray Diffraction (XRD) and atomic force microscopy (AFM), respectively. The shift of optical absorption edge to shorter wavelengths, than that for the bulk CdS, indicates that the nanometer-sized particles represent the quantum confinement effects. The band gaps are calculated from the optical absorption studies, ranging from 2.88 to 2.41 eV. Particle sizes are estimated from the effective mass approximation. In addition, particle sizes are calculated from the XRD studies that are in good agreement with those estimated from the band gap values. XRD results illustrate nanocrystals have cubic structure with (111) preferred orientation. AFM pictures of the CdS/PVA surfaces show cluster formation of nanoparticles