Hot spots engineering in hierarchical silver nanocap array for surface-enhanced Raman scattering

We proposed a rapid, simple and room-temperature method to fabricate hierarchical silver nanocap arrays, in which hot spots could be facilely engineered on three-dimensional curved surface. Both optical property and surface-enhanced Raman scattering (SERS) activity displayed non-monotonic Ag thickness dependence. Furthermore, the simulation results obtained by finite-difference time-domain (FDTD) method reveal that hot spots intensity and density on three-dimensional curved surface significantly vary and strongly depend on deposited Ag thickness. The investigation opens a possibility for facile fabrication of SERS substrate with promising hot spot engineering on three-dimensional surface and extremely high SERS activity.

Highlights► Rapid and room-temperature method to fabricate hierarchical Ag array is proposed. ► Arrays consist of submicrosized ordered caps with nanoscale Ag particles on surface. ► Controlling Ag deposition thickness leads to various surface roughnesses. ► Both optical property and SERS activity display non-monotonic behaviors. ► Hot spots engineering on three-dimensional curved surface is facilely achieved.