Graphene-enhanced Raman spectroscopy of thymine adsorbed on single-layer graphene

Abstract

Graphene-enhanced Raman scattering (GERS) spectra and coherent anti-Stokes Raman scattering (CARS) of thymine molecules adsorbed on a single-layer graphene were studied. The enhancement factor was shown to depend on the molecular groups of thymine. In the GERS spectra of thymine, the main bands are shifted with respect to those for molecules adsorbed on a glass surface, indicating charge transfer for thymine on graphene. The probable mechanism of the GERS enhancement is discussed. CARS spectra are in accord with the GERS results, which indicates similar benefit from the chemical enhancement.

Sensitive Raman detection of human recombinant interleukin-6 mediated by DCDR/GERS hybrid platforms

“…4 and 5). This result is consistent with the existence of additional Raman signal amplication of the IL-6 solutions when they are deposited onto the hybrid rGO/Si substrates, which would be associated with GERS phenomena [48][49][50] Interestingly, GERS amplication for biomolecules have been described mainly for aromatic amino acids and polypeptides, where the rGO Raman enhancement was related to the interactions of both aromatic p-p stacking and the local electric eld from the remaining oxygenated groups on the rGO sheet. [23][24][25][26][27] Coincidentally, in our case, IL-6 presents aromatic domains and basic amino acid residues that would favor a strong adsorption to the surface of the RGO sheet.…”

Potential Application of h-BNC Structures in SERS and SEHRS Spectroscopies: A Theoretical Perspective

“…Thus, a strong enlargement of the Raman activities of target molecules adsorbed on a graphene sheet is a priori unexpected. The experiments confirmed the small enhancement factor [2,3,4], reaching two orders of magnitude at most, and its origin in charge transfer (CT) transitions between the surface and the adsorbed molecule [1,6,10,12]. Even though a chemical mechanism based on charge transfer excitations could yield larger enhancement factors (EF), it is less likely that these factors might reach the Raman enhancements obtained with metallic nanoparticles, which were reported to be larger than ten orders of magnitude [15].…”

“…Since the discovery of the Surface Enhanced Raman Scattering (SERS) activity of extended graphene sheets [1], also known as Graphene Enhanced Raman Scattering (GERS) phenomena [2,3,4], experimental and theoretical efforts have been devoted to elucidate the possible enhancement mechanisms [5,6,7,8,9,10,11,12,13]. It is well-known that the closeness of the energy gap in extended graphene structures makes the optical activity and plasmon emission to be located within the THz region [14], ruling out the possibility of electromagnetic enhancement using UV laser sources.…”

Gold micro- and nano-particles for surface enhanced vibrational spectroscopy of pyridostigmine bromide

“…Chemical mechanism of Raman enhancement is connected with the electron transfer from the substrate to the absorbed molecule. It becomes possible, when the exciting light resonantly transfers electron from the Fermi level of the substrate to the lowest unoccupied molecular orbital of the adsorbed analyte [18][19][20][21][22][23].…”