Reassessing SERS enhancement factors: using thermodynamics to drive substrate design

2017 ◽  
Vol 205 ◽  
pp. 547-560 ◽  
Author(s):  
J. A. Guicheteau ◽  
A. Tripathi ◽  
E. D. Emmons ◽  
S. D. Christesen ◽  
Augustus W. Fountain
Keyword(s):  
Enhancement Factor ◽  
Sers Substrate ◽  
Us Army ◽  
Analytical Technique ◽  
Sers Substrates ◽  
Advantages And Disadvantages ◽  
Metal Interaction ◽  
Sers Enhancement ◽  
Aromatic Thiols ◽  
Underlying Mechanisms

Over the past 40 years fundamental and application research into Surface-Enhanced Raman Scattering (SERS) has been explored by academia, industry, and government laboratories. To date however, SERS has achieved little commercial success as an analytical technique. Researchers are tackling a variety of paths to help break through the commercial barrier by addressing the reproducibility in both the SERS substrates and SERS signals as well as continuing to explore the underlying mechanisms. To this end, investigators use a variety of methodologies, typically studying strongly binding analytes such as aromatic thiols and azarenes, and report SERS enhancement factor calculations. However a drawback of the traditional SERS enhancement factor calculation is that it does not yield enough information to understand substrate reproducibility, application potential with another analyte, or the driving factors behind the molecule–metal interaction. Our work at the US Army Edgewood Chemical Biological Center has focused on these questions and we have shown that thermodynamic principles play a key role in the SERS response and are an essential factor in future designs of substrates and applications. This work will discuss the advantages and disadvantages of various experimental techniques used to report SERS enhancement with planar SERS substrates and present our alternative SERS enhancement value. We will report on three types of analysis scenarios that all yield different information concerning the effectiveness of the SERS substrate, practical application of the substrate, and finally the thermodynamic properties of the substrate. We believe that through this work a greater understanding for designing substrates will be achieved, one that is based on both thermodynamic and plasmonic properties as opposed to just plasmonic properties. This new understanding and potential change in substrate design will enable more applications for SERS based methodologies including targeting molecules that are traditionally not easily detected with SERS due to the perceived weak molecule–metal interaction of substrates.

scholarly journals Label-free highly sensitive probe detection with novel hierarchical SERS substrates fabricated by nanoindentation and chemical reaction methods

2019 ◽  
Vol 10 ◽  
pp. 2483-2496
Author(s):  
Jingran Zhang ◽  
Tianqi Jia ◽  
Yongda Yan ◽  
Li Wang ◽  
Peng Miao ◽  
...  
Keyword(s):  
Ag Nanoparticles ◽  
Enhancement Factor ◽  
Low Cost ◽  
Hierarchical Structures ◽  
Production Method ◽  
Copper Surface ◽  
Sers Substrate ◽  
Label Free ◽  
Sers Substrates ◽  
Highly Sensitive

Nanostructures have been widely employed in surface-enhanced Raman scattering (SERS) substrates. Recently, in order to obtain a higher enhancement factor at a lower detection limit, hierarchical structures, including nanostructures and nanoparticles, appear to be viable SERS substrate candidates. Here we describe a novel method integrating the nanoindentation process and chemical redox reaction to machine a hierarchical SERS substrate. The micro/nanostructures are first formed on a Cu(110) plane and then Ag nanoparticles are generated on the structured copper surface. The effect of the indentation process parameters and the corrosion time in the AgNO3 solution on the Raman intensities of the SERS substrate with hierarchical structures are experimentally studied. The intensity and distribution of the electric field of single and multiple Ag nanoparticles on the surface of a plane and with multiple micro/nanostructures are studied with COMSOL software. The feasibility of the hierarchical SERS substrate is verified using R6G molecules. Finally, the enhancement factor using malachite green molecules was found to reach 5.089 × 109, which demonstrates that the production method is a simple, reproducible and low-cost method for machining a highly sensitive, hierarchical SERS substrate.

scholarly journals Optimizing the SERS enhancement of a facile gold nanostar immobilized paper-based SERS substrate

RSC Advances ◽  
2017 ◽  
Vol 7 (27) ◽  
pp. 16264-16272 ◽  
Author(s):  
Shuai He ◽  
Jefri Chua ◽  
Eddie Khay Ming Tan ◽  
James Chen Yong Kah
Keyword(s):  
Enhancement Factor ◽  
Low Cost ◽  
Sers Substrate ◽  
Sers Enhancement ◽  
Gold Nanostar

Schematic of study to optimize the SERS enhancement factor of a low cost and facile gold nanostar (AuNS)-based paper-SERS substrate through optimizing the paper materials, immobilization strategies, and SERS acquisition conditions.

scholarly journals Optimum fabrication parameters for preparing high performance SERS substrates based on Si pyramid structure and silver nanoparticles

RSC Advances ◽  
2021 ◽  
Vol 11 (50) ◽  
pp. 31189-31196
Author(s):  
Nguyen Thuy Ngoc Thuy ◽  
Huynh Nguyen Thanh Luan ◽  
Van Vo Kim Hieu ◽  
Mai Thi Thanh Ngan ◽  
Nguyen Tri Trung ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Food Security ◽  
Enhancement Factor ◽  
High Performance ◽  
Sers Substrate ◽  
Practical Applications ◽  
Sers Substrates ◽  
Pyramid Structure ◽  
Fabrication Parameters

AgNPs@PSi substrate can detect abamectin molecules at concentrations as low as 5.7 × 10−9 M, with an enhancement factor of 1 × 106. Such a remarkable SERS substrate promises great potential for practical applications in food security.

Prosperity to challenges: recent approaches in SERS substrate fabrication

2017 ◽  
Vol 36 (1) ◽  
Author(s):  
Lei Ouyang ◽  
Wen Ren ◽  
Lihua Zhu ◽  
Joseph Irudayaraj
Keyword(s):  
Raman Spectroscopy ◽  
Single Molecule ◽  
Surface Enhanced Raman Spectroscopy ◽  
Structural Features ◽  
In Situ Monitoring ◽  
Raman Signal ◽  
Sers Substrate ◽  
Basic Step ◽  
Analytical Technique ◽  
Sers Substrates

AbstractSurface-enhanced Raman spectroscopy (SERS) is a highly promising analytical technique that has been widely applied in health and environment monitoring. As a vibrational spectroscopic tool, its fingerprint spectrum contains abundant molecular information, and the greatly enhanced signal can be used to detect analytes at extremely low concentration, even down to the single molecule level. Because water molecules give very weak Raman response, Raman spectroscopy has also been applied for in situ monitoring of targets in solution. However, the Raman signal of an analyte could only be enhanced when it is in proximity to the SERS substrate, which enhances the signal depending on the shape, size, and orientation of the particles constituting the substrate. Further, when using the method for the detection of various analytes, it is necessary to functionalize the SERS substrates, with recognition ligands and encapsulation with a suitable shell among others. Hence, the fabrication of suitable substrates is a basic step in SERS-related research. Tremendous effort has been expended in the last decade in this area, resulting in the development of substrates with unique properties. In this review, we will introduce recent achievements in SERS substrate fabrication based on their structural features. Synthesized nanoparticles, two-dimensional planar substrates, and three-dimensional substrates with effective volume will be discussed in the context of their synthesis strategies along with their characteristic properties. In the future, with further improvement in SERS substrates, the applicability of SERS for detecting a range of analytes in complex environment will become possible.

Validation of SERS enhancement factor measurements

2017 ◽  
Vol 49 (3) ◽  
pp. 462-471 ◽  
Author(s):  
R. Pilot ◽  
R. Bozio
Keyword(s):  
Enhancement Factor ◽  
Sers Enhancement

Silver nanoparticle-incorporated ultralong hydroxyapatite nanowires with internal reference as SERS substrate for trace environmental pollutant detection

2018 ◽  
Vol 42 (22) ◽  
pp. 17950-17957
Author(s):  
Lei Zhang ◽  
Yongquan Luo ◽  
Yameng Zhao ◽  
Boxin Guan ◽  
Lingyi Zhang ◽  
...  
Keyword(s):  
Silver Nanoparticle ◽  
Environmentally Friendly ◽  
Environmental Pollutant ◽  
Sers Substrate ◽  
Internal Reference ◽  
Sers Substrates ◽  
Pollutant Detection

Silver nanoparticle-incorporated HAPNWs as SERS substrates exhibit unique characteristics including stability, convenience and simple and environmentally friendly preparation.

scholarly journals In-Situ Grown Silver Nanoparticles on Nonwoven Fabrics Based on Mussel-Inspired Polydopamine for Highly Sensitive SERS Carbaryl Pesticides Detection

Nanomaterials ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 384 ◽  
Author(s):  
Zhiliang Zhang ◽  
Tiantian Si ◽  
Jun Liu ◽  
Guowei Zhou
Keyword(s):  
Silver Nanoparticles ◽  
Collection Efficiency ◽  
High Sensitivity ◽  
Sers Substrate ◽  
Analytical Sensitivity ◽  
Sers Substrates ◽  
Rapid Sampling ◽  
Highly Sensitive ◽  
Highly Sensitive Detection

The rapid sampling and efficient collection of target molecules from a real-world surface is fairly crucial for surface-enhanced Raman scattering (SERS) to detect trace pesticide residues in the environment and in agriculture fields. In this work, a versatile approach was exploited to fabricate a flexible SERS substrate for highly sensitive detection of carbaryl pesticides, using in-situ grown silver nanoparticles (AgNPs)on non-woven (NW) fabric surfaces based on mussel-inspired polydopamine (PDA) molecules. The obtained NW@PDA@AgNPs fabrics showed extremely sensitive and reproducible SERS signals toward crystal violet (CV) molecules, and the detection limit was as low as 1.0 × 10−12 M. More importantly, these NW@PDA@AgNPs fabrics could be directly utilized as flexible SERS substrates for the rapid extraction and detection of trace carbaryl pesticides from various fruit surfaces through a simple swabbing approach. It was identified that the detection limits of carbaryl residues from apple, orange, and banana surfaces were approximately decreased to 4.02 × 10−12, 6.04 × 10−12, and 5.03 × 10−12 g, respectively, demonstrating high sensitivity and superior reliability. These flexible substrates could not only drastically increase the collection efficiency from multifarious irregular-shaped matrices, but also greatly enhance analytical sensitivity and reliability for carbaryl pesticides. The fabricated flexible and multifunctional SERS substrates would have great potential to trace pesticide residue detection in the environment and bioscience fields.

Core/shell Ag@silicate nanoplatelets and poly(vinyl alcohol) spherical nanohybrids fabricated by coaxial electrospraying as highly sensitive SERS substrates

RSC Advances ◽  
2016 ◽  
Vol 6 (71) ◽  
pp. 67204-67211 ◽  
Author(s):  
Chih-Wei Chiu ◽  
Po-Hsien Lin
Keyword(s):  
Vinyl Alcohol ◽  
Large Scale ◽  
High Efficiency ◽  
Poly Vinyl Alcohol ◽  
Core Shell ◽  
Sers Substrate ◽  
Sers Substrates ◽  
Highly Sensitive ◽  
Coaxial Electrospray

A novel flexible, freestanding, large-scale, and disposable SERS substrate of core/shell Ag@silicate and poly(vinyl alcohol) spherical nanohybrids, fabricated by coaxial electrospray, allows for the high-efficiency detection of adenine from DNA.

Self-assembly of various silver nanocrystals on PmPD/PAN nanofibers as a high-performance 3D SERS substrate

The Analyst ◽  
2015 ◽  
Vol 140 (16) ◽  
pp. 5707-5715 ◽  
Author(s):  
Peng Jia ◽  
Bing Cao ◽  
Jianqiang Wang ◽  
Jin Qu ◽  
Yuxuan Liu ◽  
...  
Keyword(s):  
Self Assembly ◽  
High Performance ◽  
Sers Substrate ◽  
Sers Substrates ◽  
Highly Sensitive ◽  
Nanofiber Mats ◽  
Pan Nanofiber

The AgNCs (AgNPs, AgNTs and AgNDs) decorated-PmPD/PAN nanofiber mats were obtained as highly sensitive 3D SERS substrates.

scholarly journals Indirect Quantification of Glyphosate by SERS Using an Incubation Process With Hemin as the Reporter Molecule: A Contribution to Signal Amplification Mechanism

2020 ◽  
Vol 8 ◽  
Author(s):  
Karen A. López-Castaños ◽  
Luis A. Ortiz-Frade ◽  
Erika Méndez ◽  
Enrique Quiroga-González ◽  
Miguel A. González-Fuentes ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Excitation Wavelength ◽  
Raman Signal ◽  
Sers Substrate ◽  
Silver Surface ◽  
Indirect Determination ◽  
Sers Substrates ◽  
Resonance Properties ◽  
Equilibrium Process ◽  
Vinyl Group

The indirect determination of the most used herbicide worldwide, glyphosate, was achieved by the SERS technique using hemin chloride as the reporter molecule. An incubation process between hemin and glyphosate solutions was required to obtain a reproducible Raman signal on SERS substrates consisting of silicon decorated with Ag nanoparticles (Si-AgNPs). At 780 nm of excitation wavelength, SERS spectra from hemin solutions do not show extra bands in the presence of glyphosate. However, the hemin bands increase in intensity as a function of glyphosate concentration. This allows the quantification of the herbicide using as marker band the signal associated with the ring breathing mode of pyridine at 745 cm−1. The linear range was from 1 × 10−10 to 1 × 10−5 M and the limit of detection (LOD) was 9.59 × 10−12 M. This methodology was successfully applied to the quantification of the herbicide in honey. From Raman experiments with and without silver nanoparticles, it was possible to state that the hemin is the species responsible for the absorption in the absence or the presence of the herbicide via vinyl groups. Likewise, when the glyphosate concentration increases, a subtle increase occurs in the planar orientation of the vinyl group at position 2 in the porphyrin ring of hemin over the silver surface, favoring the reduction of the molecule. The total Raman signal of the hemin-glyphosate incubated solutions includes a maximized electromagnetic contribution by the use of the appropriate laser excitation, and chemical contributions related to charge transfer between silver and hemin, and from resonance properties of Raman scattering of hemin. Incubation of the reporter molecule with the analyte before the conjugation with the SERS substrate has not been explored before and could be extrapolated to other reporter-analyte systems that depend on a binding equilibrium process.

Sign in / Sign up

Export Citation Format

Share Document