Single-molecule surface-enhanced Raman spectroscopy: a perspective on the current status

Abstract

This perspective presents an overview of single-molecule surface-enhanced Raman scattering (sm-SERS). Our overview is organized as a brief theoretical background, discussion of the factors that enhance SERS, various experimental preparations for inserting a single molecule in a hot spot, recent sm-SERS experiments, and a perspective. Although, there have been numerous review papers on sm-SERS, we mainly concentrated on the logical development of sm-SERS on the basis of the fundamental concepts and their physical significance, so that readers outside this field can understand the motivation and the underlying physics when describing current sm-SERS measurements. Indeed, understanding such current sm-SERS experiments conducted by representative groups would be very helpful for readers to answer for themselves the fundamental and practical questions surrounding sm-SERS: (1) what information can sm-SERS provide? (2) Which factors based on the SERS mechanism should be considered to significantly amplify the SERS signal? (3) What kinds of related microscopy techniques could be combined with sm-SERS to attain more meaningful results? (4) Which statistical approaches can be used and how they can be applied to properly analyze sm-SERS data? We hope that this review article can help readers answer these questions.

Plasmonic nanopore-based platforms for single-molecule Raman scattering

“…Therefore, additional Raman enhancement factor is 2.5 4 E40 and total Raman enhancement factor is over 2 Â 10 8 which evidently satisfies the requirement for single-molecule SERS (10 7 -10 8 ) [25]. It is worth mentioning that this figure was obtained based on considerations of limitations on available fabrication technologies.…”

High resolution fabrication of nanostructures using controlled proximity nanostencil lithography

“…Nanogap structures are important in a broad range of devices, including surface enhanced Raman spectroscopy (SERS) 10 , single molecule fluorescence sensing 11,12 , transverse electrodes for nanopore sensing 13 , spin 14 and ultrafast 15 transistors, molecular electronics 16,17 , magnetic tunneling junctions 18 , and nanomagnetics 19 . In many of these applications, device performance depends critically on both the gap size as well as the feature dimensions 20 , and is sensitive to geometric and surface imperfections that often lead to a significant deterioration in performance 21 .…”

Intense Raman scattering on hybrid Au/Ag nanoplatforms for the distinction of MMP-9-digested collagen type-I fiber detection

“…Ag NCsfibAu_NR sample S_3fibAu_NR exhibited the highest I sers and EF (6.92 Â 10 8 ). Since the intra-Ag NC and Au NR plasmon energies are most probably matched that increase the electron oscillation at Raman-active sites, the intensity of Raman signals and the value of EF thus increased (Lee et al, 2013;Rycenga et al, 2009;Sivashanmugan et al, 2015Sivashanmugan et al, , 2013aSivashanmugan et al, , 2013bYamamoto et al 2013;Yang et al 2014;Yilmaz et al 2014). In Fig.…”