In-Situ Seeding Synthesis Of Walnut Kernel-Like Ag Nanostructures With Highly Efficient Sers Performance

By an in-situ seeding synthetic route, with biocompatible reagents being used, walnut kernel-like Ag nanostructures (Ag nanowalnuts) composed of nanoplates were fabricated. The in-situ formation of seeds and introduction of complex [Ag-3(C6H5O7)(n+1)](3n-) were indispensable steps for this kind of self-assembled nanostructure. The size of Ag nanowalnuts was in the range of 200-400 nm and the thickness of a single nanoplate was about 30 nm. The morphology of nanoplates was of variety, and their surface was bumpy. Such Ag nanostructures with rough surface and high curvature provided plenty of 'hot spots' on a single particle for surface-enhanced Raman scattering (SERS) enhancement. Experimental results indicated that the Ag nanowalnuts offered great surface enhancement for 4-mercaptobenzoic acid and malachite green molecules. The limit of detection was low to 10(-10) and 10(-8) M, respectively.