Wavelength Dependence of Raman Enhancement from Gold Nanorod Arrays: Quantitative Experiment and Modeling of a Hot Spot Dominated System

Abstract

Surface-enhanced Raman scattering (SERS) spectra from molecules adsorbed on the surface of vertically aligned gold nanorod arrays exhibit a variation in enhancement factor (EF) as a function of excitation wavelength that displays little correlation with the elastic optical properties of the surface. The key to understanding this lack of correlation and to obtaining agreement between experimental and calculated EF spectra lies with consideration of randomly distributed, sub-10 nm gaps between nanorods forming the substrate. Intense fields in these enhancement “hot spots” make a dominant contribution to the Raman scattering and have a very different spectral profile to that of the elastic optical response. Detailed modeling of the electric field enhancement at both excitation and scattering wavelengths was used to quantitatively predict both the spectral profile and the magnitude of the observed EF.

Application of AAO Matrix in Aligned Gold Nanorod Array Substrates for Surface-Enhanced Fluorescence and Raman Scattering

“…18,19 2D nanorod arrays have been applied to enable surface-enhanced Raman scattering (SERS) spectra from molecules adsorbed on the surface of vertically aligned gold nanorod arrays In addition, gold nanorods possess good chemical stability and biocompatibility under biological conditions. 17,21 Fluorescence spectroscopy is another well-known spectroscopic method playing a major role in selective detection of bioanalytes. 23 Similarly to the effect of increasing the Raman scattering of molecules, the presence of LSPRs on plasmonic metal nanostructures can enhance the fluorescence signal from locally situated fluorophores, a process known as metal enhanced (MEF) or surface enhanced fluorescence (SEF).…”

Controlling surface-plasmon-polaritons launching with hot spot cylindrical waves in a metallic slit structure

“…[23][24][25][26][27][28][29] Because of the strong field enhancement, hot spots have been applied in enormous areas of the second harmonics, Raman enhancement, surface-enhanced optical sensing, spectroscopy, and microscopy. [23][24][25][26][27][28] However, seldom works have done to concern the conversion of the localized hot spots to the nearby propagating SPPs in a platform. This conversion between the localized hot spots and propagating SPPs will be an important issue in integrated plasmonic circuits, and it can also provide a new degree of freedom in designing SPP-based devices.…”

CNTs-anchored egg shell membrane decorated with Ag-NPs as cheap but effective SERS substrates

“…Compared with the dispersed Ag colloidal nanoparticles (NPs), delicate spatial arrangement of Ag-NPs on the 3D-frameworks may ensure better reproducibility and reliability of SERS signals, and also provide additional signal enhancement due to the newly generated "hot spots" and possible cavity resonances [7][8][9]. Thus much effort has been made on the fabrication of SERS substrates with various arrangements of Ag nanostructures on nonplasmonic 3D-frameworks with high uniformity [6][7][8][9][10][11][12][13][14][15][16][17]. However, sophisticated fabrication procedures with high cost are usually required in the previously reported studies, which are time/ energy-consuming.…”