Self-assembled synthesis of Ag nanodendrites and their applications to SERS

In this paper, SiO2 nanoparticles were synthesized using self-assembly for their fabrication. The SiO2 particles as a micro reactor were soaked into silver nitrate (AgNO3) aqueous solution. The dendritic Ag nanoparticles were prepared by a reaction of AgNO3 with template agent (CTAB) and AgBr decomposed into elemental Ag nanoparticles under visible light irradiation on the SiO2 micro reactor. The morphology and structure of synthesized Ag dendrites were determined by employing following techniques: X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), ultraviolet visible spectroscopy (UV–vis). The correlated surface-enhanced Raman scattering (SERS) effects have been investigated when 2-Mercaptobenzothiazole (2-MBT) was used as a Raman probe. Especially, the possible growth process was proposed by arresting the growth at a series of intermediate morphology stages during the shape evolution of Ag dendrites based on TEM observations. The results clearly showed that the dendritic Ag nanostructures could be obtained through oriented attachment of nanoparticles along a crystallographically special direction and the morphology of the dendrites was dependent on the reaction duration. Moreover, the investigation of the SERS revealed that the Ag nanodendrites were an excellent substrate with significant enhancement effect.