Prosperity to challenges: recent approaches in SERS substrate fabrication

2017 ◽  
Vol 36 (1) ◽  
Author(s):  
Lei Ouyang ◽  
Wen Ren ◽  
Lihua Zhu ◽  
Joseph Irudayaraj

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.

Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 2905
Author(s):  
Buse Bilgin ◽  
Cenk Yanik ◽  
Hulya Torun ◽  
Mehmet Cengiz Onbasli

Surface-enhanced Raman spectroscopy (SERS) is a highly sensitive and molecule-specific detection technique that uses surface plasmon resonances to enhance Raman scattering from analytes. In SERS system design, the substrates must have minimal or no background at the incident laser wavelength and large Raman signal enhancement via plasmonic confinement and grating modes over large areas (i.e., squared millimeters). These requirements impose many competing design constraints that make exhaustive parametric computational optimization of SERS substrates prohibitively time consuming. Here, we demonstrate a genetic-algorithm (GA)-based optimization method for SERS substrates to achieve strong electric field localization over wide areas for reconfigurable and programmable photonic SERS sensors. We analyzed the GA parameters and tuned them for SERS substrate optimization in detail. We experimentally validated the model results by fabricating the predicted nanostructures using electron beam lithography. The experimental Raman spectrum signal enhancements of the optimized SERS substrates validated the model predictions and enabled the generation of a detailed Raman profile of methylene blue fluorescence dye. The GA and its optimization shown here could pave the way for photonic chips and components with arbitrary design constraints, wavelength bands, and performance targets.


2021 ◽  
Vol 31 (4) ◽  
Author(s):  
Quynh-Ngan Luong ◽  
Tran Cao Dao ◽  
Thi Thu Vu ◽  
Manh Cuong Nguyen ◽  
Nhu Duong Nguyen

Surface-enhanced Raman spectroscopy (SERS) is increasingly being used as a method for detecting traces of contaminants in a variety of specimens. In order to maximize SERS’s performance, the most important thing is to have highly active SERS substrates. In this report, we present a simple method for synthesizing silver nanodendrites (AgNDs) on the surface of a copper (Cu) plate using chemical deposition method. The results showed that, after fabrication, a large number of fern-like AgNDs formed on the Cu surface. These AgNDs are distributed evenly across the entire Cu surface with a relatively thick density. The prepared AgNDs were applied as SERS substrates for detecting Rhodamine 6G (R6G) in chili powders. The results showed that, using the prepared AgNDs substrates, as low as 10−10 M R6G in chili powders can be detected. This demonstrates the applicability of fabricated AgNDs as a highly active SERS substrate.


Nanophotonics ◽  
2022 ◽  
Vol 0 (0) ◽  
Author(s):  
Yanlin Mi ◽  
Yinzhou Yan ◽  
Mengyuan Wang ◽  
Lixue Yang ◽  
Jing He ◽  
...  

Abstract Surface-enhanced Raman spectroscopy (SERS) has been widely investigated and employed as a powerful optical analytical technique providing fingerprint vibrational information of molecules with high sensitivity and resolution. In addition to metallic nanostructure, dielectric micro-/nano-structures with extraordinary optical manipulation properties have demonstrated capability in enhanced Raman scattering with ultralow energy losses. Here we report a facile cascaded structure composed of a large microsphere (LMS) and a small microsphere array with Ag nanoparticles as a novel hybrid SERS substrate, for the first time. The cascaded microsphere-coupled SERS substrate provides a platform to increase the molecular concentration, boost the intensity of localized excitation light, and direct the far-field emission, for giant Raman enhancement. It demonstrates the maximum enhancement factor of Raman intensity greater than 108 for the limit of detection down to 10−11 M of 4-nitrothiphenol molecules in aqueous solution. The present work inspires a novel strategy to fabricate cascaded dielectric/metallic micro-/nano-structures superior to traditional SERS substrates towards practical applications in cost-effective and ultrahigh-sensitive trace-detection.


Crystals ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 24
Author(s):  
Affi Nur Hidayah ◽  
Djoko Triyono ◽  
Yuliati Herbani ◽  
Rosari Saleh

Deltamethrin pesticides can cause inflammation, nephrotoxicity and hepatotoxicity as well as affect the activity of antioxidant enzymes in tissues. As a result of this concern, there is a rising focus on the development of fast and reliable pesticide residue testing to minimise potential risks to humans. The goal of this study is to use Au-Ag colloid nanoparticles as liquid surface-enhanced Raman spectroscopy (SERS) to improve the Raman signal in the detection of deltamethrin pesticide in a brewed tea. The liquid SERS system is fascinating to study due to its ease of use and its unlikeliness to cause several phenomena, such as photo-bleaching, combustion, sublimation and even photo-catalysis, which can interfere with the Raman signal, as shown in the SERS substrate. Our liquid SERS system is simpler than previous liquid SERS systems that have been reported. We performed the detection of pesticide analyte directly on brewed tea, without diluting it with ethanol or centrifuging it. Femtosecond laser-induced photo-reduction was employed to synthesise the liquid SERS of Au, Au-Ag, and Ag colloidal nanoparticles. The SERS was utilised to detect deltamethrin pesticide in brewed tea. The result showed that liquid SERS-based Ag NPs significantly enhance the Raman signal of pesticides compared with liquid SERS-based Au NPs and Au-Ag Nanoalloys. The maximum residue limits (MRLs) in tea in Indonesia are set at 10 ppm. Therefore, this method was also utilised to detect and improve, to 0.01 ppm, the deltamethrin pesticide Limit of Detection (LOD).


2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Gregory Mogilevsky ◽  
Laura Borland ◽  
Mark Brickhouse ◽  
Augustus W. Fountain III

Raman spectroscopy is an analytical technique with vast applications in the homeland security and defense arenas. The Raman effect is defined by the inelastic interaction of the incident laser with the analyte molecule’s vibrational modes, which can be exploited to detect and identify chemicals in various environments and for the detection of hazards in the field, at checkpoints, or in a forensic laboratory with no contact with the substance. A major source of error that overwhelms the Raman signal is fluorescence caused by the background and the sample matrix. Novel methods are being developed to enhance the Raman signal’s sensitivity and to reduce the effects of fluorescence by altering how the hazard material interacts with its environment and the incident laser. Basic Raman techniques applicable to homeland security applications include conventional (off-resonance) Raman spectroscopy, surface-enhanced Raman spectroscopy (SERS), resonance Raman spectroscopy, and spatially or temporally offset Raman spectroscopy (SORS and TORS). Additional emerging Raman techniques, including remote Raman detection, Raman imaging, and Heterodyne imaging, are being developed to further enhance the Raman signal, mitigate fluorescence effects, and monitor hazards at a distance for use in homeland security and defense applications.


Micromachines ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 282 ◽  
Author(s):  
Qi Qi ◽  
Chunhui Liu ◽  
Lintao Liu ◽  
Qingyi Meng ◽  
Shuhua Wei ◽  
...  

Surface-enhanced Raman spectroscopy (SERS) substrates with high sensitivity and reproducibility are highly desirable for high precision and even molecular-level detection applications. Here, large-scale uniformly hybrid nanoparticle-enhanced Raman spectroscopy (NERS) substrates with high reproducibility and controllability were developed. Using oxygen plasma treatment, large-area and uniformly rough polystyrene sphere (URPS) arrays in conjunction with 20 nm Au films (AuURPS) were fabricated for SERS substrates. Au nanoparticles and clusters covered the surface of the URPS arrays, and this increased the Raman signal. In the detection of malachite green (MG), the fabricated NERS substrates have high reproducibility and sensitivity. The enhancement factor (EF) of Au nanoparticles and clusters was simulated by finite-difference time-domain (FDTD) simulations and the EF was more than 104. The measured EF of our developed substrate was more than 108 with a relative standard deviation as low as 6.64%–13.84% over 15 points on the substrate. The minimum limit for the MG molecules reached 50 ng/mL. Moreover, the Raman signal had a good linear relationship with the logarithmic concentration of MG, as it ranged from 50 ng/mL to 5 μg/mL. The NERS substrates proposed in this work may serve as a promising detection scheme in chemical and biological fields.


Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1741
Author(s):  
Hiroyuki Takei ◽  
Kazuki Nagata ◽  
Natalie Frese ◽  
Armin Gölzhäuser ◽  
Takayuki Okamoto

Surface-enhanced Raman spectroscopy (SERS) is a powerful technique for obtaining structural information of molecules in solution at low concentrations. While commercial SERS substrates are available, high costs prevent their wide-spread use in the medical field. One solution is to prepare requisite noble metal nanostructures exploiting natural nanostructures. As an example of biomimetic approaches, butterfly wing scales with their intricate nanostructures have been found to exhibit exquisite SERS activity when coated with silver. Selecting appropriate scales from particular butterfly species and depositing silver of certain thicknesses leads to significant SERS activity. For morphological observations we used scanning electron microscopes as well as a helium ion microscope, highly suitable for morphological characterization of poorly conducting samples. In this paper, we describe a protocol for carrying out SERS measurements based on butterfly wing scales and demonstrate its LOD with a common Raman reporter, rhodamine 6 G. We also emphasize what special care is necessary in such measurements. We also try to shed light on what makes scales work as SERS substrates by carefully modifying the original nanostructures. Such a study allows us to either use scales directly as a raw material for SERS substrate or provides an insight as to what nanostructures need to be recreated for synthetic SERS substrates.


The Analyst ◽  
2021 ◽  
Author(s):  
Harmke Susanna Siebe ◽  
Qinglu Chen ◽  
Xinyuan Li ◽  
Yikai Xu ◽  
Wesley Browne ◽  
...  

Surface-enhanced Raman spectroscopy (SERS) is an emerging analytical technique for chemical analysis, due to its combination of short measurement time, high sensitivity and molecular specificity. However, the application of SERS...


2019 ◽  
Vol 7 (32) ◽  
pp. 9926-9932 ◽  
Author(s):  
Yukun Gao ◽  
Nan Yang ◽  
Sichen Lu ◽  
Tingting You ◽  
Penggang Yin

Plasmon-driven photocatalytic reaction is monitored at the gas-liquid-solid interface by using superhydrophobic surface enhanced Raman spectroscopy (SERS) substrates.


RSC Advances ◽  
2015 ◽  
Vol 5 (104) ◽  
pp. 85845-85853 ◽  
Author(s):  
Mirkó Palla ◽  
Filippo G. Bosco ◽  
Jaeyoung Yang ◽  
Tomas Rindzevicius ◽  
Tommy S. Alstrom ◽  
...  

Based on single molecule surface-enhanced Raman spectroscopy (SERS) intensity distribution theory, a mathematical model is developed for highly sensitive biomolecular quantification using Raman mapping on SERS substrates with planar geometries.


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