An efficient double template strategy to construct large-area and highly ordered silver "urchin-like" arrays for sensitive SERS analysis

Plasmonic metal nanostructures possessing plentiful gaps or tips have attracted great attention in surface enhanced Raman scattering (SERS) due to their superior performance. Herein, we present an efficient fabrication strategy to construct a large-area and highly ordered 3D silver "urchin-like" array (SULA) based on the ultra-thin alumina membrane (UTAM) mask and the self-assembled polystyrene spheres template. Numerical simulations reveal that the proposed SULA possesses enormous hotspots at the tips of Ag nanocones and in the crevice gaps between the adjacent Ag nanocaps responsible for high sensitivity with an enhancement factor of 1.8 x 106 and excellent reproducibility with a relative standard deviation of 8.3% in SERS analysis. Furthermore, the SULA substrate exhibits great SERS performance for detecting the contaminant crystal violet and thiram in real water environments and excellent linear intensity-concentration dependence relationships. The results indicate the proposed SULAs are promising to be developed as high-performance SERS platforms in qualitative and quantitative trace contaminants in complex water environments.