CdSe/ZnS QD incorporated microbeads for ultra-sensitive chemo-sensor applications

CdSe/ZnS QD microbeads for detecting toxic and bio-materials with high sensitivity were prepared by the incorporation of CdSe/ZnS QDs into mesoporous silica. CdSe/ZnS core/shell QDs were synthesized from precursors such as CdO and zinc stearate with lower toxicity than pyrophoric precursors. In order to enhance the number of QDs encoded into the silica beads, the spherical mesoporous silica with the pore size of 20 - 30 nm is surface-modified by octadecyl silane. The QDs and QD microbeads were characterized by using transmission electron microscopy, IR spectroscopy and fluorescence microscopy. Based on the surface derivative reaction of the alkyl chains on the microbeads, the compatibility between the surface wetting properties of the QDs and the mesoporous silica is noted to play a key role in enhancing the diffusion of QDs into mesoporous silica.