Nanoparticle self-assembly based tripetaloid arrayed structures as surface-enhanced raman scattering substrates

This paper reports a novel highly-ordered tripetaloid arrayed structure (TPAS) which performs very well as an active surface-enhanced Raman scattering (SERS) substrate for its notable reproducibility and enormous SERS enhancement factor (EF). The TPAS is easily fabricated by anisotropic etching of a self-assembly silica-nanoparticle bilayer and a following metal deposition. Electromagnetic simulation indicates that the edge protrusions and narrow gaps of the structure act as hot spots. SERS experiments show that the EF of Au-film-covered TPAS is 12 times higher than that of regular Au-film-over-nanoparticles (AuFON). The spatially average EF of the TPAS is as high as 5.7×10⁶, and the local EF of its hot spots is much higher.