Linear and Nonlinear Optical Properties of CdS and CdSe Nanoparticles Stabilized with Poly(N-vinyl-2-pyrrolidone)
Abstract
CdS and CdSe nanoparticles were prepared in organic solvents in the presence of poly(N-vinyl-2-pyrrolidone) (PVP). PVP plays an essential role in preventing the flocculation of concentrated nanoparticles (stabilizing effect), and in controlling the particle size under the influence of the solvent used. FT-IR measurements were performed to study the effect of the functional groups of PVP on particle size control at molecular levels. The PVP-coated CdS and CdSe nanoparticles obtained were dispersed in acrylonitrile-styrene (AS) copolymer or poly(2-hydroxyethyl methacrylate) (PHEMA) organic films, and third-order nonlinear optical susceptibilities |χ (3) | of these films were measured using a degenerate four-wave mixing (DFWM) technique. The largest |χ (3) | value of 1.1×10 -7 esu was obtained by excitonic resonant excitation for about 4.0 vol% CdS-doped PHEMA film.