Preparation of a new core-shell Ag@SiO_2 nanocomposite and its application for fluorescence enhancement

摘要

Ag@SiO_2 nanoparticles with different shell thicknesses were synthesized via modified St?ber method. Rhodamine B isothiocyanate was covalently bound onto the surface of Ag@SiO_2 nanoparticles to form fluorescent core-shell Ag@SiO_2 nanocomposites. Effects of shell thickness on the fluorescence enhancement were examined using the corresponding nanobubbles prepared by cyanide etching as a control. The result showed that the fluorescence enhanced as the shell thickness increased till the distance between fluorophore and metal core reached about 75 nm with the optimal enhancement factor of ～5-folds. Further increasing of fluorophore-metal distance caused a decrease in the enhancement factor.