Spatial Position Control of CdS Nanoclusters using a Self-Assembled Diblock Copolymer Template

摘要

Core-shell structured quantum dots (QDs) such as CdSe/ZnS and Au/CdSe/ZnS nanoparticles are synthesized, and enhanced photoluminescent properties are observed in these nanoparticles as compared to that of bare core nanoparticles. For controlling the spatial position of nanoparticles with block copolymers, it was found that the mercapto-ethanol modified CdS nanoparticles have a preferential binding to the poly(ethylene oxide) block of polystyrene-b- poly(ethylene oxide) diblock copolymer, with a saturated concentration of 7% in volume fraction, and the composites have a better thermal stability. When CdS clusters have been sequestered into the PEO domain, the morphology of CdS/PS-b- PEO composite thin film was found to be transformed from cylinders to spheres by the presence of hydrogen bonds between surface-hydroxylated CdS and PEO. In another case Pyridine-modified CdSe nanoparticles were found to selectively disperse in the poly(4-vinylpyridine) block of polystyrene-b-poly(4- vinylpyridine) diblock copolymer, with their luminescence retaining as in the pure state. Moreover, the photoluminescence and electroluminescence of the dendritic copolyfluorene are dramatically enhanced when a few percentage of CdS nanoparticles was incorporated.