Centrifugation-based separation of triangular silver nanoplates from multi-shaped colloidal silver nanoparticles for fabrication of surface-enhanced Raman-scattering substrates

Abstract

. We synthesize and separate triangular silver nanoplates (TSNPs) from a mixture of colloidal silver nanoparticles of different shapes and sizes, aiming at fabrication of substrates for a surface-enhanced Raman scattering (SERS). The TSNPs are successfully synthesized via a photochemical process involving Ag nanoseeds. This is confirmed by the UV-visible spectroscopy and transmission electron-microscopy analyses. Centrifugation-based separation techniques are employed to isolate the TSNPs and minimize the other nanoparticle morphologies, thus resulting in a good SERS performance. The separated TSNPs manifest a remarkable sensitivity, with the detection limit amounting to 10 –12 M in the case of Rhodamine 6G molecules. A linear relationship between the Rhodamine 6G concentration and the Raman-peak intensity demonstrates a great potential of our SERS technique. Hence, our study combines a successful synthesis and separation of the TSNPs with demonstration of their efficient SERS performance. The latter offers new possibilities for the ultrasensitive trace-level detection of substances. These findings contribute to the development of reliable SERS measurements and the advance in the field of nanomaterial-based sensing techniques.