Surface enhanced Raman spectroscopy of molecular oxygen adsorbed on polydiacetylene single crystals

Batchelder, D. N.; Poole, N. J.; Bloor, D.

doi:10.1016/0009-2614(81)80463-0

Cited by 31 publications

(6 citation statements)

References 24 publications

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“…Surface‐enhanced Raman scattering (SERS) refers to the enhancement of Raman vibrational modes of molecules located at the vicinity of a plasmonic, quantum‐confined nanostructure . Such spectral enhancement originates from (a) chemical interactions through charge‐transfer between the molecule and the plasmonic nanostructure and (b) coupling of the Raman vibrational tensor to the plasmonic electromagnetic field created at the surface of the nanostructure . Although the SERS intensity predominantly originates from electromagnetic enhancement, the chemical enhancement often contributes to SERS spectral shifts and non‐uniform enhancement of the spectral features.…”

Section: Introductionmentioning

confidence: 99%

Surface‐enhanced Raman scattering platform operating over wide pH range with minimal chemical enhancement effects: Test case of tyrosine

Moronshing

Bhaskar

Mondal

et al. 2019

J Raman Spectroscopy

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Decoupling the contributions of electromagnetic and chemical enhancements in surface-enhanced Raman scattering (SERS) would lead to greater reliability and applicability in biological systems that involve large, localized pH gradients. However, suppressing short-range, chemical enhancement effects in SERS has proved challenging due to unavoidable charge-transfer interactions between analyte and the SERS platforms. This extends to both lithographically fabricated top-down and self-assembled bottom-up SERS platforms. Here, we employ a Soret effect-driven monodisperse nanoparticle assembly (Soret colloids [SCs]) with negligible surface charge (ξ < 16 mV) that provides exceptional SERS enhancement (analytical enhancement factor~10 6 ) contributed predominantly by excitation of localized surface plasmon resonance (electromagnetic enhancement) with minimal electrostatic or charge-transfer-based short-range interactions. Significantly, the low ξ of SCs is invariant over a wide pH range (pH 4-7) indicating minimal electrostatic surface charge. The interaction of such SCs with ionic analytes such as tyrosine leads to uniform SERS dictated by electromagnetic enhancement mechanism. The absence of contribution from chemical enhancement is clearly established by the vibrational fingerprints of tyrosine that are devoid of any spectral shifts originating from charge transfer between tyrosine and SCs. Accordingly, all features of the tyrosine that are independent of pH such as C-H stretch (2,700-3,000 cm −1 ) and C-C stretch (1,440 cm −1 ) and C-C-C bending (1,010 cm −1 ) are completely preserved without any spectral shifts. Simultaneously, pH-dependent vibrational features of tyrosine such as N-H stretch (1,545 cm −1 ), C¼O stretch (1,700 cm −1 ), COO − stretch (1,640 cm −1 ), C-O stretch (1,240 cm −1 ), and amide III bands (1,246 and 1,260 cm −1 ) are clearly observed. The intensities of such bands correspond exactly to the ionic state of tyrosine as dictated by the pH of the medium. This is reinforced by the crossover in the intensity of the pH-dependent vibrational modes (C-O vs. COOstretch, COO − vs. NH 3 + stretch) that coincides with the isoelectric pH of tyrosine. Finally, reliable quantification of the charge and concentration of tyrosine using SCs

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Section: Introductionmentioning

confidence: 99%

Surface‐enhanced Raman scattering platform operating over wide pH range with minimal chemical enhancement effects: Test case of tyrosine

Moronshing

Bhaskar

Mondal

et al. 2019

J Raman Spectroscopy

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“…The CT process is considered to be a resonant Raman-like enhancement, which is associated with the excited state of the molecule-metal system and the charge transfer between the molecule and the metal surface (or ad-atom and ad-clusters). [56][57][58][59][60][61] Different models have been proposed. Otto et al considered that the CT process proceeds via a four-step process: the generation of the surface plasmon excitation, the formation of the negative ionic molecule, the electron returning to the metal and finally the emission by the radiating photons.…”

Section: Introduction To Sers Mechanismsmentioning

confidence: 99%

Surface-enhanced Raman spectroscopic study of p-aminothiophenol

Huang

Zhu

et al. 2012

Phys. Chem. Chem. Phys.

249

274

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p-aminothiophenol (PATP) is an important molecule for surface-enhanced Raman spectroscopy (SERS). It can strongly interact with metallic SERS substrates and produce very strong SERS signals. It is a molecule that has often been used for mechanistic studies of the SERS mechanism as the photon-driven charge transfer (CT) mechanism is believed to be present for this molecule. Recently, a hot debate over the SERS behavior of PATP was triggered by our finding that PATP can be oxidatively transformed into 4,4'-dimercaptoazobenzene (DMAB), which gives a SERS spectra of so-called "b2 modes". In this perspective, we will give a general overview of the SERS mechanism and the current status of SERS studies on PATP. We will then demonstrate with our experimental and theoretical evidence that it is DMAB which contributes to the characteristic SERS behavior in the SERS spectra of PATP and analyze some important experimental phenomena in the framework of the surface reaction instead of the contribution "b2 modes". We will then point out the existing challenges of the present system. A clear understanding of the reaction mechanism for nitrobenzene or aromatic benzene will be important to not only understand the SERS mechanism but to also provide an economic way of producing azo dyes with a very high selectivity and conversion rate.

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“…Such long-term stability and good physicochemical resistance of the p-DCHD NCs are mainly due to the high degree of crystallinity and close-packed (or defect-free) rigid structure in the crystal lattices of the p-DCHD NCs, which would protect and prevent the reaction of ROS with the polymer backbone. 48 Moreover, such a polymer structure also contributes to the high thermal stability of p-DCHD NCs even above 250 °C (Fig. S7 † ).…”

Section: Resultsmentioning

confidence: 99%

“…3(b) , but all the samples did exhibit photocatalytic activity at a maximum wavelength of around 450 nm, a region which almost corresponded to the increase in photocurrent in the action spectrum of p-DCHD. 48 Evidently, it was found that the charge separation of e–h pairs generated in the photoexcited p-DCHD NCs was an initial process.…”

Section: Resultsmentioning

confidence: 99%

A promising visible light-driven photocatalytic activity of conjugated polymer nanocrystals

et al. 2018

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Surface enhanced Raman spectroscopy of molecular oxygen adsorbed on polydiacetylene single crystals

Cited by 31 publications

References 24 publications

Surface‐enhanced Raman scattering platform operating over wide pH range with minimal chemical enhancement effects: Test case of tyrosine

Surface‐enhanced Raman scattering platform operating over wide pH range with minimal chemical enhancement effects: Test case of tyrosine

Surface-enhanced Raman spectroscopic study of p-aminothiophenol

A promising visible light-driven photocatalytic activity of conjugated polymer nanocrystals

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