Graphene‐Veiled Gold Substrate for Surface‐Enhanced Raman Spectroscopy

Xu, Weigao; Xiao, Jiaqi; Chen, Yanfeng; Chen, Yabin; Ling, Xi; Zhang, Jin

doi:10.1002/adma.201204355

Cited by 217 publications

(201 citation statements)

References 36 publications

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“…While complex and laborious procedures are needed for coupling graphene to nanostructured surfaces, 7,8,17 GO coating can be simply obtained by physisorption of GO sheets in…”

Section: ■ Introductionmentioning

confidence: 99%

“…While complex and laborious procedures are needed for coupling graphene to nanostructured surfaces, 7,8,17 GO coating can be simply obtained by physisorption of GO sheets in aqueous solution. 18−21 Beside obvious advantages of this approach, a detailed investigation on how the assembly of GO should be conducted to control adsorption geometry and optical properties at the interface is still lacking.…”

Section: ■ Introductionmentioning

confidence: 99%

“…13−15 Recent findings also sustained the convenient use of GO and of mild reduced GO in generating SERS signals that accurately resemble the native spectrum of the molecules in solution without frequency shifts, which instead are typically generated as a consequence of the interaction with graphene or metal. 16 Overall, veiling plasmonic nanoparticles with GO sheets is perceived as a favorite strategy to fabricate advanced SERS substrates which hold the promise of improved sensitivity, signal stability, and reproducibility.While complex and laborious procedures are needed for coupling graphene to nanostructured surfaces, 7,8,17 GO coating can be simply obtained by physisorption of GO sheets in …”

mentioning

confidence: 99%

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Controlled Veiling of Silver Nanocubes with Graphene Oxide for Improved Surface-Enhanced Raman Scattering Detection

Banchelli

Tiribilli

Angelis

et al. 2016

ACS Appl. Mater. Interfaces

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Hybrid graphene oxide (GO)/metal nanocomposites have been recently proposed as novel surface-enhanced Raman scattering (SERS) substrates. Despite an increasing interest in these systems, standardization in their fabrication process is still lacking but urgently required to support their use for real-life applications. In this work we investigate how the assembly of GO should be conducted to control adsorption geometry and optical properties at the interface with plasmonic nanostructures as monolayer assemblies of silver nanocubes, by tuning main experimental parameters including GO concentration and self-assembly time. We finally identified the experimental conditions for building up a close-fitting soft dressing of the plasmonic surface, which shows optimal characteristics for flexible and reliable SERS detection. KEYWORDS: plasmonic nanoparticles, sensing, self-assembly, Raman spectroscopy, quartz crystal microbalance ■ INTRODUCTIONSurface-enhanced Raman scattering (SERS) spectroscopy is as a robust and versatile analytical technique with the ability to offer detailed and label-free chemical information with molecular selectivity and ultrasensitivity. 1−5 The SERS effect relies on huge electromagnetic fields concentrated at the metal surface of a plasmonic nanostructure, which dramatically enhance the Raman signal of molecules placed in its close proximity. In this respect, efficient SERS enhancements are typically generated within less than 10 nm from the metal surface and are mostly confined within the so-called "hot spots", i.e. highly curved nanoregions or gaps and junctions between adjacent nanoparticles. The ability to gather molecules in these regions in a homogeneous and reproducible manner represents a current impediment that is still preventing further diffusion of SERS as a systematic analytical tool.A recent trend toward upgrading the performance of SERS technology relies on the combination of plasmonic nanostructures made of silver and gold with graphene. 6−9 Graphene is a single-atom-thick sheet of sp 2 -hybridized carbon atoms arranged in a honeycomb lattice. A number of unique chemical, electronic, optical, and structural properties make this material a preferred choice for greatly improving electronic and photonic devices. 10,11 With a focus on SERS, current efforts are taking advantage of a thin graphene coating in drawing and concentrating target molecules as well as in conferring the plasmonic surface with a passivating layer that discards possible disturbances and signal variability induced by metal−molecule interactions. 12 Main fabrication methods of graphene sheets include mechanical peel-off, epitaxial growth, and chemical vapor deposition (CVD), which, however, appear unsuitable for large-scale production of graphene, ultimately limiting its practical application. A convenient alternative is now represented by graphene oxide (GO), which is derived by oxidation of graphite in the form of graphene sheets with abundant oxygen-containing functionalities. These confer chemical st...

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“…While complex and laborious procedures are needed for coupling graphene to nanostructured surfaces, 7,8,17 GO coating can be simply obtained by physisorption of GO sheets in…”

Section: ■ Introductionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

Controlled Veiling of Silver Nanocubes with Graphene Oxide for Improved Surface-Enhanced Raman Scattering Detection

Banchelli

Tiribilli

Angelis

et al. 2016

ACS Appl. Mater. Interfaces

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“…In a graphene-mediated SERS (G-SERS) substrate [13][14][15][16][17][18] ; the monolayer graphene (1G) provides an atomically flat surface for Raman enhancement. Because the graphene surface is chemically inert, signals from G-SERS substrates have great advantages over normal SERS by providing cleaner vibrational information free from various metal-molecule interactions (molecules cannot interact with the chemically active metal by graphene-mediated interactions) and being more stable against photo-induced damage 13 .…”

Section: Introductionmentioning

confidence: 99%

Plasmon-driven reaction controlled by the number of graphene layers and localized surface plasmon distribution during optical excitation

et al. 2015

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Graphene-plasmonic hybrid platforms have attracted an enormous amount of interest in surface-enhanced Raman scattering (SERS); however, the mechanism of employing graphene is still ambiguous, so clarification about the complex interaction among molecules, graphene, and plasmon processes is urgently needed. We report that the number of graphene layers controlled the plasmon-driven, surface-catalyzed reaction that converts para-aminothiophenol (PATP)-to-p,p9-dimercaptoazobenzene (DMAB) on chemically inert, graphene-coated, silver bowtie nanoantenna arrays. The catalytic reaction was monitored by SERS, which revealed that the catalytic reaction occurred on the chemical inertness monolayer graphene (1G)-coated silver nanostructures. The introduction of 1G enhances the plasmon-driven surface-catalyzed reaction of the conversion of PATP-to-p,p9-DMAB. The chemical reaction is suppressed by bilayer graphene. In the process of the catalytic reaction, the electron transfer from the PATP molecule to 1G-coated silver nanostructures. Subsequently, the transferred electrons on the graphene recombine with the hot-hole produced by the localized surface plasmon resonance of silver nanostructures. Then, a couple of PATP molecules lost electrons are catalyzed into the p,p9-DMAB molecule on the graphene surface. The experimental results were further supported by the finite-difference time-domain method and quantum chemical calculations.

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“…As reported previously, the enhancement also depends on the geometry of the deposited metal. [28][29][30] However, the morphology of both layers is similar, and thus, the enhancement can be attributed particularly to the graphene-metal interactions than to the sample geometry.…”

Section: Resultsmentioning

confidence: 97%

Surface‐enhanced Raman spectra on graphene

Weis

Vejpravová

Verhagen

et al. 2017

J Raman Spectroscopy

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Surface-enhanced Raman spectroscopy is a valuable tool for inspection of trace concentrations of various molecules; hence, this method has a great potential for characterization of functionalised graphene. However, to make this method a reliable analytical tool, the influence of the metal-graphene interactions on Raman spectra of the graphene must be understood. Here, the surface-enhanced Raman spectra of exfoliated single-layer graphene covered with gold or silver thin layers were studied. The metal-graphene interactions resulted in the broadening of the G mode and the 2D mode of graphene. A change of the 2D mode dispersion was also observed. The effects were found to be weaker for the silver layer; however, the Raman signal enhancement of the graphene features was found to be significantly stronger in case of the silver layer. Various scenarios of the observed effects are discussed: graphene-plasmon interaction, charge transfer between the metal and graphene, and selective enhancement at the lattice and topographic defects. Copyright © 2017 John Wiley & Sons, Ltd.Keywords: charge transfer; graphene; graphene-plasmon interaction; metal-graphene interaction; SERS IntroductionMetals such as gold and silver are known to strongly enhance the Raman signal of pristine graphene. [1,2] In particular, the approach is extremely important for the chemically functionalized graphene samples because it allows to identify the functional groups on the graphene surface. [3] However, it is also known that graphene may strongly interact with the metals, and this interaction is also mirrored in the Raman spectra. [4] Consequently, it is important to follow these effects.Raman spectra of a pristine graphene typically consist of the G mode, which appears at about 1,580 cm −1 , and the 2D mode, which is significantly dispersive and its wavenumber increases with the laser excitation energy. The dispersion comes from the slope of the Dirac cone; therefore, changes in the dispersion reflect changes in the electronic structure of the graphene. [5,6] In case that structural imperfections are present in a graphene sample, one can also observe the defect scattering related D and D' modes at around 1,350 and 1,620 cm −1 , respectively. As reported by several authors previously, the enhancement of a particular Raman mode of graphene depends on the excitation energy of the laser and plasmonic characteristics of the metallic structure in contact with the graphene, and consequently, the enhancement factors for the D, D', G, and 2D modes can be very different. [7,8] Moreover, not only the kind of metal but also the shape, dimensions, and mutual geometry of the metallic structure and graphene are of utmost importance.In a typical experiment, the enhancement of the Raman signal can be achieved by deposition of a thin layer of silver or gold or their nanoparticles over the graphene. This geometry, however, reduces intensity of the incoming light, and also, the scattered light is partly absorbed by the metal. Another option is to intercalate metal un...

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Graphene‐Veiled Gold Substrate for Surface‐Enhanced Raman Spectroscopy

Cited by 217 publications

References 36 publications

Controlled Veiling of Silver Nanocubes with Graphene Oxide for Improved Surface-Enhanced Raman Scattering Detection

Controlled Veiling of Silver Nanocubes with Graphene Oxide for Improved Surface-Enhanced Raman Scattering Detection

Plasmon-driven reaction controlled by the number of graphene layers and localized surface plasmon distribution during optical excitation

Surface‐enhanced Raman spectra on graphene

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