Centrifugation-Based Separation of Triangular Silver Nanoplates from Multi-Shaped Colloidal Silver Nanoparticles for Fabrication of Surface-Enhanced Raman-Scattering Substrates

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.