Progress in plasmonic engineering of surface-enhanced Raman-scattering substrates toward ultra-trace analysis

Abstract

This review describes advances made toward the application of surface-enhanced Raman scattering (SERS) in sensitive analysis and diagnostics. In the early sections of this review we briefly introduce the fundamentals of SERS including a discussion of SERS at the single-molecule level. Applications relevant to trace analysis, environmental monitoring, and homeland security and defense, for example high explosives and contaminant detection, are emphasized. Because the key to wider application of SERS analysis lies in the development of highly enhancing substrates, in the second half of the review we focus our attention on the extensive progress made in designing innovative soluble, supported, and ordered SERS-active nano-architectures to harness the potential of this technique toward solving current and emerging analytical tasks. No attempt or claim is made to review the field exhaustively in its entirety nor to cover all applications, but only to describe several significant milestones and progress made in these important areas and to provide some perspective on where the field is quickly moving.

Application of Surface-Enhanced Raman Spectroscopy for Detection of Beta Amyloid Using Nanoshells

“…To overcome this problem, the use of surface-enhanced Raman spectroscopy (SERS) has been instituted. SERS provides significant enhancement of the Raman intensity, on the order of 10 6 to 10 14 times, through electromagnetic field enhancement and chemical enhancement that increases the Raman cross section of the individual molecule when the molecule of interest is close to a roughened metal [40][41][42][43][44][45][46]. These enhancement factors are considered to represent the SERS signal at a Raman-scattered frequency υ S in Eq.…”

“…These enhancement factors are considered to represent the SERS signal at a Raman-scattered frequency υ S in Eq. 1 [45,46].…”

“…The enhancement is strongest when the surface plasmons are in resonance with both the excitation and Raman-scattered fields, and this enhancement is dependent, to the fourth power, on the local nanostructure field of the metal. These strong spatial and local nanostructure field dependencies may be producing the small, localized "hot spots" of extremely strong enhancement known to occur with SERS, which give the potential for trace analyte detection but also make the production of reproducible SERS surfaces difficult [45,46]. Nanoshells are spherical nanoparticles with a dielectric core surrounded by a metal shell with plasmon resonances that can be adjusted by altering the ratio of the core diameter to the shell diameter [47].…”

pH-Dependent Surface-enhanced Raman Scattering Analysis of Maleimide and Succinimide on Ag Nanocolloidal Surfaces

“…9 Ever since its discovery, 10 the surface-enhanced Raman scattering (SERS) phenomenon has become one of the most sensitive techniques for monitoring adsorbates on metal substrates at the submonolayer coverage limit. 11,12 The quantum chemistry community has regarded density functional theory (DFT) as a general procedure for studying molecules' physical properties and confirming their vibrational assignments. 13 Few reports have explored the direct chemisorption of MI or SI on metal surfaces.…”

Chemical approach to fabrication of semicontinuous Au nanolayers for SERS applications

“…The SERS effect, mainly attributed to the electromagnetic field enhancement caused by localized surface plasmon excitation in metallic nanostructures through the incident laser light, is strongly dependent on the morphology of metallic nanostructures [2]. Thus, it is not surprising that numerous studies have been dedicated to the design and fabrication of highly active SERS substrates based on nanostructured films and metallic nanoparticles [3][4][5]. Examples of SERS active structures include colloid aggregates [6], substrates fabricated by nanosphere lithography (NSL) [7], adaptive silver films (ASF) fabricated by electron beam evaporation [8][9] and Au and Ag nanoshells [10][11].…”