scholarly journals Surface-Enhanced Raman Spectroscopy on Hybrid Graphene/Gold Substrates near the Percolation Threshold

Nanomaterials ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 164 ◽  
Author(s):  
Dmitry E. Tatarkin ◽  
Dmitry I. Yakubovsky ◽  
Georgy A. Ermolaev ◽  
Yury V. Stebunov ◽  
Artem A. Voronov ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Percolation Threshold ◽  
Surface Enhanced Raman Spectroscopy ◽  
Effective Dielectric Constant ◽  
Gold Films ◽  
Maximum Enhancement ◽  
Sers Signal ◽  
Gold Substrates ◽  
Surface Enhanced ◽  
Surface Enhanced Raman

Graphene is a promising platform for surface-enhanced Raman spectroscopy (SERS)-active substrates, primarily due to the possibility of quenching photoluminescence and fluorescence. Here we study ultrathin gold films near the percolation threshold fabricated by electron-beam deposition on monolayer CVD graphene. The advantages of such hybrid graphene/gold substrates for surface-enhanced Raman spectroscopy are discussed in comparison with conventional substrates without the graphene layer. The percolation threshold is determined by independent measurements of the sheet resistance and effective dielectric constant by spectroscopic ellipsometry. The surface morphology of the ultrathin gold films is analyzed by the use of scanning electron microscopy (SEM) and atomic force microscopy (AFM), and the thicknesses of the films in addition to the quartz-crystal mass-thickness sensor are also measured by AFM. We experimentally demonstrate that the maximum SERS signal is observed near and slightly below the percolation threshold. In this case, the region of maximum enhancement of the SERS signal can be determined using the figure of merit (FOM), which is the ratio of the real and imaginary parts of the effective dielectric permittivity of the films. SERS measurements on hybrid graphene/gold substrates with the dye Crystal Violet show an enhancement factor of ~105 and also demonstrate the ability of graphene to quench photoluminescence by an average of ~60%.

scholarly journals Revisiting semicontinuous silver films as surface-enhanced Raman spectroscopy substrates

2019 ◽  
Vol 10 ◽  
pp. 1048-1055 ◽  
Author(s):  
Malwina Liszewska ◽  
Bogusław Budner ◽  
Małgorzata Norek ◽  
Bartłomiej J Jankiewicz ◽  
Piotr Nyga
Keyword(s):  
Raman Spectroscopy ◽  
Percolation Threshold ◽  
Physical Vapor Deposition ◽  
Surface Enhanced Raman Spectroscopy ◽  
Silver Films ◽  
Analytical Technique ◽  
Detection And Identification ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
The Many

Surface-enhanced Raman spectroscopy (SERS) is a very promising analytical technique for the detection and identification of trace amounts of analytes. Among the many substrates used in SERS of great interest are nanostructures fabricated using physical methods, such as semicontinuous metal films obtained via electron beam physical vapor deposition. In these studies, we investigate the influence of morphology of semicontinuous silver films on their SERS properties. The morphologies studied ranged from isolated particles through percolated films to almost continuous films. We found that films below the percolation threshold (transition from dielectric-like to metal-like) made of isolated silver structures provided the largest SERS enhancement of 4-aminothiophenol (4-ATP) analyte signals. The substrate closest to the percolation threshold has the SERS signal about four times lower than the highest signal sample.

A Practical Method to Fabricate Gold Substrates for Surface-Enhanced Raman Spectroscopy

2008 ◽  
Vol 62 (9) ◽  
pp. 992-1000 ◽  
Author(s):  
Ratna Tantra ◽  
Richard J. C. Brown ◽  
Martin J. T. Milton ◽  
Dipak Gohil
Keyword(s):  
Raman Spectroscopy ◽  
Practical Method ◽  
Surface Enhanced Raman Spectroscopy ◽  
Gold Substrates ◽  
Surface Enhanced ◽  
Surface Enhanced Raman

Effect of substituents on surface equilibria of thiophenols and isoquinolines on gold substrates studied using surface-enhanced Raman spectroscopy

2020 ◽  
Vol 22 (28) ◽  
pp. 15953-15965
Author(s):  
Erik D. Emmons ◽  
Jason A. Guicheteau ◽  
Augustus W. Fountain ◽  
Ashish Tripathi
Keyword(s):  
Raman Spectroscopy ◽  
Binding Affinity ◽  
Dipole Moments ◽  
Surface Adsorption ◽  
Surface Enhanced Raman Spectroscopy ◽  
Effect Of Substituents ◽  
Adsorption Equilibria ◽  
Gold Substrates ◽  
Surface Enhanced ◽  
Surface Enhanced Raman

The effect of substituents on the surface adsorption equilibria on gold substrates was studied using surface-enhanced Raman spectroscopy in order to determine the effects of the localized dipole moments and charge donating/withdrawing properties on the binding affinity.

scholarly journals Comparative Performance of Citrate, Borohydride, Hydroxylamine and β-Cyclodextrin Silver Sols for Detecting Ibuprofen and Caffeine Pollutants by Means of Surface-Enhanced Raman Spectroscopy

Nanomaterials ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2339
Author(s):  
Michele Lemos de Souza ◽  
Juan Carlos Otero ◽  
Isabel López-Tocón
Keyword(s):  
Raman Spectroscopy ◽  
Emerging Contaminants ◽  
Limit Of Detection ◽  
Surface Enhanced Raman Spectroscopy ◽  
Molar Ratio ◽  
Sers Substrate ◽  
Comparative Performance ◽  
Sers Signal ◽  
Surface Enhanced ◽  
Surface Enhanced Raman

The detection of emerging contaminants in the aquatic environment, such as ibuprofen and caffeine, was studied by means of surface-enhanced Raman spectroscopy (SERS) using Ag nanoparticles (AgNPs) synthesized with β-cyclodextrin (βCD) as a reducing agent. The effect on the SERS signal of different molar ratios of Ag+/βCD in the synthesis route and the aging process of AgNPs were investigated by using trans-cinnamic as a test molecule. The SERS effectiveness of these β-cyclodextrin colloids (Ag@βCD) was also checked and compared with that of other silver sols usually employed in SERS synthesized by using other reducing agents such as citrate, borohydride and hydroxylamine. All the synthesized SERS substrates were characterized by different techniques. The experimental results indicate that Ag@βCD with the more diluted Ag+/βCD molar ratio showed the best SERS signal, enabling detection at trace concentrations of 0.5 µM in the case of trans-cinnamic acid. The Ag@βCD sols also showed the best sensitivity for detecting ibuprofen and caffeine, reaching the lowest limit of detection (0.1 mM). The proposed synthetic route for Ag@βCD sols provides an improved SERS substrate for detecting organic pollutants with better performance than other standard silver sols.

On-Line Spectroscopic Characterization of Sodium Cyanide with Nanostructured Gold Surface-Enhanced Raman Spectroscopy Substrates

2002 ◽  
Vol 56 (12) ◽  
pp. 1524-1530 ◽  
Author(s):  
Peter M. Tessier ◽  
Steven D. Christesen ◽  
Kate K. Ong ◽  
Eva M. Clemente ◽  
Abraham M. Lenhoff ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Surface Enhanced Raman Spectroscopy ◽  
Sodium Cyanide ◽  
Raman Signal ◽  
Gold Films ◽  
Porous Gold ◽  
Wide Range ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
On Line

To implement surface-enhanced Raman spectroscopy as a practical detection method, highly enhancing, stable, and reproducible substrates need to be fabricated in an efficient manner, and their performance in different solution environments should be well characterized. In this work structured porous gold films have been fabricated using colloidal crystals to template gold nanoparticles. These films were integrated into an on-line flow chamber and used to study the effects of pH and other additives on the detection of sodium cyanide. The gold films proved to be highly enhancing and were used to detect cyanide over a wide range of pH values in the concentration range of ∼2 to 200 ppb. The Raman signal intensity could be increased by lowering the pH after the adsorption of cyanide, which was likely due to both a change in the ionization state and a conformational change of the bound molecules. The peak intensity could also be enhanced multifold by treating the substrate with silver nitrate. Cyanide could be removed from the substrates using hydrochloric acid, although this also passivated the structures, and the activity could only be restored partially with tannic acid. These results provide a rational method to optimize the online detection of cyanide in water.

Laser writing of single-crystalline gold substrates for surface enhanced Raman spectroscopy

2017 ◽  
Vol 4 (7) ◽  
pp. 075027 ◽  
Author(s):  
Astha Singh ◽  
Geeta Sharma ◽  
Neeraj Ranjan ◽  
Kshitij Mittholiya ◽  
Anuj Bhatnagar ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Surface Enhanced Raman Spectroscopy ◽  
Laser Writing ◽  
Single Crystalline ◽  
Gold Substrates ◽  
Surface Enhanced ◽  
Surface Enhanced Raman

Advanced silver and gold substrates for surface-enhanced Raman spectroscopy of pesticides

2021 ◽  
pp. 1-11
Author(s):  
Petar Asenov Atanasov ◽  
Nikolay Nedyalkov Nedyalkov ◽  
Naoki Fukata ◽  
Wipakorn Jevasuwan
Keyword(s):  
Raman Spectroscopy ◽  
Surface Enhanced Raman Spectroscopy ◽  
Gold Substrates ◽  
Surface Enhanced ◽  
Surface Enhanced Raman

Surface-enhanced raman spectroscopy on ultrathin gold/graphene substrates near the percolation threshold

2021 ◽  
Author(s):  
D. E. Tatarkin ◽  
D. I. Yakubovsky ◽  
D. A. Komissar ◽  
Y. V. Stebunov ◽  
A. V. Arsenin ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Percolation Threshold ◽  
Surface Enhanced Raman Spectroscopy ◽  
Surface Enhanced ◽  
Surface Enhanced Raman
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