SERS Surfaces for Electrochemistry

Over the last few years there has been an increasing move away from roughened electrode surfaces for electrochemical SE(R)RS with all their inherent limitations 

Im et al. [128] have used optical lithography combined with atomic layer deposi- 

The most commonly used template particles are either polystyrene or silica spheres. These can be synthesized or obtained commercially and are available in a range of sizes (from about 100 nm upwards) with a narrow coefficient of variation ( 2%) in diameter. The size variation is important because the more uniform the size of the particles the more regular the packing. The particles can be assembled into templates in a variety of ways, including evaporation of the solvent [138], convective self-assembly [139-141], Langmuir-Blodgett deposition [142, 143], or by withdrawing the substrate slowly from a suspension of the colloidal particles [144]. The optimum methods for the assembly of the silica and polystyrene particles differ because of the differences in their densities and hence sedimentation rates. Once assembled on the surface the particles act as a template to define the deposition. 

Comparison of the enhancement factors between triangular nanoparticle arrays formed by nanosphere lithography and the MFON structures [8] shows that although the enhancement factor is about 10 times larger for the triangular 

Lu et al. [172] used a template assembled from uniform silica spheres to produce both an ordered macroporous Au-Ag nanostructure and an ordered hollow Au-Ag nanostructured film by electroless deposition. Both films showed SERS activity but were rather rough on the nanoscale and the authors attributed the surface enhancement to the presence of interconnected nanostructured aggregates and nanoscale roughness. 

---