Tip-to-tip assembly of urchin-like Au nanostar at water-oil interface for surface-enhanced Raman spectroscopy...

Au Nanostar (NS) monolayer as a surface enhanced Raman scattering (SERS) substrate has been synthesized by self-assembly at a water-oil interface. It is confirmed from the experiment and simulation results that the Au NS monolayer includes lots of "hot spots" at or between the tips of the Au NSs, enhancing the local electromagnetic fields and giving rise to strong SERS signals sequentially. The limit of detection is determined to be down to 4.2 × 10^-12 M for rhodamine 6G. Furthermore, the Au NS monolayer can detect multiple molecules, including thiabendazole, methylene blue, 4-mercaptobenzoic acid, and p-amino thiophenol, indicating that the SERS substrate composed of Au NS monolayer has potential applications in analytical chemistry, food safety, and environmental safety.