Synthesis of Gold Nanostar Arrays as Reliable, Large-Scale, Homogeneous Substrates for Surface-Enhanced Raman Scattering Imaging and Spectroscopy

We report a two-step approach for the fabrication of quasi-hexagonal ordered arrays of star-shaped gold nanoparticles (gold nanostars) as reliable, large-scale homogeneous substrates for surface-enhanced Raman scattering (SERS) spectroscopy by a combination of block-copolymer micelle nanolithography and electroless deposition. The applicability of this platform for SERS imaging is demonstrated by pH-sensitive Raman measurements of 4-mercaptobenzoic acid adsorbed to the nanostars in the array. A homogeneous enhancement factor of similar to 10(5) was observed on the nanostar monolayer over an area of several hundreds of square micrometers.