Surface-enhanced Raman spectroscopy based on ordered nanocap arrays

Engineering of SERS Substrates Based on Noble Metal Nanomaterials for Chemical and Biomedical Applications

“…The most obvious example can be found in the preparation of gold nanorods, which involves seed formation and growth (74). Ag nanocubes with uniform edge lengths controllable in the range of 30-200 nm have been prepared by using preformed spherical or cubic seeds, in which the size was adjusted by varying the amount of AgNO 3 precursor added in the reaction solution (77). They claimed that the calculated EFs of Ag nanocubes did not vary much with the increase in size because both I SERS and N SERS became larger with increasing cube size.…”

Engineering Metal Nanostructure for SERS Application

“…One of the important parameters to characterize SERS substrates is the enhancement factor (EF), which is especially true for the practical application of SERS and the comparison with the theoretical calculation [10,15]. In fact, the most widely used definition of the enhancement factor is according to the following equation [1,15,16], which describes the overall enhancement in Raman scattering…”

“…As a result, there have appeared many researches focusing on preparing ideal noble metallic nanostructures as SERS substrates [5]. Taking Ag and Au nanostructures as examples, various shapes have emerged [10], such as nanocubes [18,19], nanorods [20,21], nanocaps [16], nanochains [22,23], nanoplates [24], honeycomb and hexagonally structured patterns [25], and nanoclusters [26]. Monodisperse nanoparticles show high SERS enhancement because of their special shapes and sizes.…”

“…MCC could be prepared by self-assembly process [68]. The target metal material can be deposited on the prepared MCC templates through plasma sputtering [69], magnetron sputtering [16], and so forth. In most cases, the templates finally need to be removed to produce ideal metal nanopatterns.…”

“…By varying the plasma sputtering deposition time, different nanopatterns with different spacing were generated, which showed different SPR intensity, thus tuning the SERS intensity. An order Ag nanocaps were also fabricated through magnetron sputtering Ag on the twodimensional PS monolayer colloidal crystal template, which showed a high SERS intensity with an enhance factor ∼10 12 using 4-mercaptopyridine (4-Mpy) as the probe molecule [16].…”