Optical properties of core/shell typed PMMA/CdS nanoparticles prepared by in situ and ex situ surfactant-free emulsion polymerization

摘要

Core/shell poly(methyl methacrylate)/cadmium sulfide (PMMA/CdS) nanoparticles were prepared by surfactant-free emulsion copolymerization with 2-(dimethylamino)ethyl methacrylate (DMAEMA) auxiliary monomer. According to the addition time of Cd~(~(2+)) ions, the synthesis of the hybrid nanoparticles was conducted in in situ and ex situ techniques. The core/shell PMMA/CdS nanoparticles synthesized by the post-addition (ex situ) of Cd~(~(2+)) ions showed a wide size distribution and interference fringes in the photoluminescence (PL) spectrum. However, these results were improved when the PMMA/CdS nanoparticles were synthesized in the presence of Cd~(2+) ions (in situ method). The in situ method made it possible to obtain monodisperse hybrid nanoparticles and fairly narrow band-gap emission.