Silica-covered Gold Nanoresonators For Optical Signal Modulating Of Graphene Quantum Dot

In recent years, core-shell nanomaterials have attracted much attention of scientists. Fabricating core-shell nano-structure appling gold nanoparticles as the core part is a hot research topic. As a new quantum dot, graphene quantum dot inherits the excellent properties of graphene and has a great application prospect. This paper puts forward using Au@SiO2nanoparticles to modulate photoluminescence of graphene quantum dot and enhance Raman signal of graphene quantum dot for the first time. The main contents of the thesis are as follows:(1)Au nanoparticles were synthesized by sodium citrate reduction. Au@SiO2nanopartices were synthesized while APTMS was used as surfactant and sodium silicate was used as the source of silicon. Au@SiO2nanopartices and Au nanoparticles were characterized. The influence of the change of silica shell thickness on UV-vis absorption spectrum of Au nanoparticles was studied.(2)Graphene oxide was synthesized. Graphene quantum dot was synthesized by hydrothermal method with graphene oxide. Graphene quantum dot and graphene oxide were characterized.(3)We utilized Au@SiO2nanopartices to modulate the fluorescence emission of graphene quantum dot. We changed the distance between Au nanoparticles and graphene quantum dot by changing the silica shell thickness. That Au@SiO2nanopartices modulated the fluorescence emission of graphene quantum dot came true by change the silica shell thickness.(4)We combined graphene quantum dot with Au nanoparticles and Au@SiO2nanopartices separately and achieved shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS). We researched on the influence of silica shell thickness on Raman enhancement effect.