Using a Fabry–Perot Cavity to Augment the Enhancement Factor for Surface-Enhanced Raman Spectroscopy and Tip-Enhanced Raman Spectroscopy

2018 ◽  
Vol 122 (26) ◽  
pp. 14865-14871 ◽  
Author(s):  
Yinsheng Guo ◽  
Song Jiang ◽  
Xu Chen ◽  
Michael Mattei ◽  
Jon. A. Dieringer ◽  
...  
2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Seongmin Hong ◽  
Xiao Li

Gold nanoparticles have been used as effective surface-enhanced Raman spectroscopy (SERS) substrates for decades. However, the origin of the enhancement and the effect of the size of nanoparticles still need clarification. Here, gold nanoparticles with different sizes from 17 to 80 nm were synthesized and characterized, and their SERS enhancement toward both 4-aminothiophenol and 4-nitrothiophenol was examined. For the same number of nanoparticles, the enhancement factor generated from the gold nanoparticles increases as the size of nanoparticles increases. Interestingly, when the concentration of gold or the total surface area of gold nanoparticles was kept the same, the optimal size of gold nanoparticles was found out to be around 50 nm when the enhancement factor reached a maximum. The same size effect was observed for both 4-aminothiophenol and 4-nitrothiophenol, which suggests that the conclusions drawn in this study might also be applicable to other adsorbates during SERS measurements.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
C. Awada ◽  
C. Dab ◽  
M. G. Grimaldi ◽  
A. Alshoaibi ◽  
F. Ruffino

AbstractWe report high optical enhancement in Ag/Au alloys and porous gold nanostructures using Surface Enhanced Raman Spectroscopy (SERS) technique. Scanning electron microscopy investigation shows the formation of Ag/Au alloys particles during irradiation of Ag–Au bilayer deposited on FTO (SnO2:F) substrate by laser fluency equal to 0.5 J/cm2 or 1.0 J/cm2 with 12 ns laser pulse duration. The dealloying process of these Au–Ag alloy particles leads to the formation of Au nanoporous particles. The obtained nanostructures were studied with SERS and revealed a promising enhancement factor in porous Au nanostructure and tunability of localized surface plasmon resonance. The highly dense strong hot spots and large specific area in porous structure of gold nanostructures is the origin of the highly enhancement factor observed experimentally and theoretically. A very good agreement between simulation and experimental results was found confirming the potential of Au/Ag alloys and particularly porous gold nanostructure in SERS application.


The Analyst ◽  
2017 ◽  
Vol 142 (23) ◽  
pp. 4422-4430 ◽  
Author(s):  
L. P. Hackett ◽  
L. L. Goddard ◽  
G. L. Liu

A plasmonic nanocone SERS substrate with a uniform enhancement factor is developed and applied for cell lysate studies.


2016 ◽  
Vol 71 (2) ◽  
pp. 279-287 ◽  
Author(s):  
Pietro Strobbia ◽  
Adam Mayer ◽  
Brian M Cullum

Surface-enhanced Raman spectroscopy (SERS) sensors offer many advantages for chemical analyses, including the ability to provide chemical specific information and multiplexed detection capability at specific locations. However, to have operative SERS sensors for probing microenvironments, probes with high signal enhancement and reproducibility are necessary. To this end, dynamic enhancement of SERS (i.e., in-situ amplification of signal-to-noise and signal-to-background ratios) from individual probes has been explored. In this paper, we characterize the use of optical tweezers to amplify SERS signals as well as suppress background signals via trapping of individual SERS active probes. This amplification is achieved through a steady presence of a single “hot” particle in the focus of the excitation laser. In addition to increases in signal and concomitant decreases in non-SERS backgrounds, optical trapping results in an eightfold increase in the stability of the signal as well. This enhancement strategy was demonstrated using both single and multilayered SERS sub-micron probes, producing combined signal enhancements of 24-fold (beyond the native 106 SERS enhancement) for a three-layered geometry. The ability to dynamically control the enhancement offers the possibility to develop SERS-based sensors and probes with tailored sensitivities. In addition, since this trapping enhancement can be used to observe individual probes with low laser fluences, it could offer particular interest in probing the composition of microenvironments not amenable to tip-enhanced Raman spectroscopy or other scanning probe methods (e.g., intracellular analyses, etc.).


2020 ◽  
Vol 8 (46) ◽  
pp. 16513-16519
Author(s):  
Eleonora Cara ◽  
Luisa Mandrile ◽  
Alessio Sacco ◽  
Andrea M. Giovannozzi ◽  
Andrea M. Rossi ◽  
...  

Determination of the SERS enhancement factor through the challenging measurement of the molecular surface density by reference-free X-ray fluorescence.


2019 ◽  
Vol 73 (8) ◽  
pp. 879-892 ◽  
Author(s):  
Hadi Savaloni ◽  
Shokoofe Goli-Haghighi ◽  
Reza Babaei

In this work, the surface engineering method is used to produce Mn helical star-shaped (pine-tree-like) nanosculptured thin films with three-, four-, and fivefold symmetries on Cu substrates using an oblique angle deposition technique together with rotation of the sample holder at certain angles. Nano structure and morphologies of the produced samples were obtained by means of atomic force microscope and field emission scanning electron microscope. Raman spectroscopy of the Mn/Cu samples impregnated by 4,4′-bipyridine (C10H8N2) solution with different concentrations, zidovudine (C10H13N5O4), and L-histidine (C6H9N3O2) was performed using 532 nm laser wavelength. A high degree of enhancement is achieved on Raman spectroscopy of all of these specimens. Comparison of the surface-enhanced Raman spectroscopy (SERS) results for 4,4′ bipyridine (bipy) obtained in this work with the published literature using Ag and Au substrates in different shapes showed a significant enhancement improvement by using Mn sculptured structures. Reduction of the bipy concentration changed the enhancement factor. Enhancement factors of 107 and 105 were obtained for threefold symmetry sample using 2.885 × 10–2 and 10–3 mol L–1 bipy concentrations, respectively. Surface-enhanced Raman spectroscopy results of this work show that Mn nanostructures designed and engineered in this work can not only replace Ag and Au materials, but also provide a much higher enhancement factor.


2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Nathan D. Israelsen ◽  
Cynthia Hanson ◽  
Elizabeth Vargis

Raman spectroscopy has enabled researchers to map the specific chemical makeup of surfaces, solutions, and even cells. However, the inherent insensitivity of the technique makes it difficult to use and statistically complicated. When Raman active molecules are near gold or silver nanoparticles, the Raman intensity is significantly amplified. This phenomenon is referred to as surface-enhanced Raman spectroscopy (SERS). The extent of SERS enhancement is due to a variety of factors such as nanoparticle size, shape, material, and configuration. The choice of Raman reporters and protective coatings will also influence SERS enhancement. This review provides an introduction to how these factors influence signal enhancement and how to optimize them during synthesis of SERS nanoparticles.


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