Surface-Enhanced Raman Spectroscopy Characterization of Pristine and Functionalized Carbon Nanotubes and Graphene

Abstract

Carbon nanotubes (CNTs) and graphene are at the center of a significant research effort due to their unique physical and chemical properties, which promise high technological impact. For the future development of all the foreseen applications, it is of particular interest the study of binding interactions between carbon nanostructures and functional groups. An appropriate method is the surface-enhanced Raman spectroscopy (SERS), which provides a large amplification of Raman signals when the probed molecule is adsorbed on a nanosized metallic surface. In this chapter, we present a review of principal results obtained applying SERS for the characterization of pristine and functionalized CNTs and graphene. The obtained results encourage us to consider SERS as a powerful method to obtain a rapid monitor of the procedures used to interface graphene and nanotubes.

Tuning Magnetic Properties of a Carbon Nanotube-Lanthanide Hybrid Molecular Complex through Controlled Functionalization

“…This is generally analyzed in terms of the ratio of the I D /I G phonon peaks originating from first order spectrum [ 21 ]. However, although this analysis is well established for graphite, graphene, double and single walled nanotubes, the Raman spectrum of the MWNTs is characteristically different and more closely resembles the spectra of chars and carbon blacks [ 9 , 22 ], thus an intense D band peak is always observed, even in unfunctionalized (pristine samples). As a result of this, the conventional I D /I G ratio comparison is not as effective in giving an accurate quantitative idea of the level of disorder [ 9 , 22 ].…”

“…However, although this analysis is well established for graphite, graphene, double and single walled nanotubes, the Raman spectrum of the MWNTs is characteristically different and more closely resembles the spectra of chars and carbon blacks [ 9 , 22 ], thus an intense D band peak is always observed, even in unfunctionalized (pristine samples). As a result of this, the conventional I D /I G ratio comparison is not as effective in giving an accurate quantitative idea of the level of disorder [ 9 , 22 ]. In fact, it has been shown that upon functionalization, the I D /I G ratio does not necessarily change significantly [ 9 ] and thus it is important to investigate alternative mechanisms for determining variations in functionalization and disorder.…”

“…As a result of this, the conventional I D /I G ratio comparison is not as effective in giving an accurate quantitative idea of the level of disorder [ 9 , 22 ]. In fact, it has been shown that upon functionalization, the I D /I G ratio does not necessarily change significantly [ 9 ] and thus it is important to investigate alternative mechanisms for determining variations in functionalization and disorder. Beyond these studies, it is known well accepted that upon increasing disorder and subsequently sp 3 content, the interpretation of Raman spectrum can be categorized into various stages where the Kroenig–Tunistra interpretation breaks down [ 7 ].…”

“…It was shown that the minor bands and satellite modes near the main G and D bands can collectively lead to a deeper understanding of the structural modification during chemical treatment. This work has also been used to address the shortfalls of the Koenig–Tuinstra relation when using the I D /I G ratio in analyzing the structural deformity of multiwalled carbon nanotubes [ 9 ]. As shown in Figure 1 a, these deconvolution schemes evaluate the weighting of minor modes adjacent to G and D bands (S + G L and D R , D L and G R ).…”

Fabrication of a Label‐free Femtomolar Electrochemical Mercury Ion Biosensor Based on Oligonucleotide Receptor Layers Hybridized with Multi‐walled Carbon Nanotubes

“…RT Raman spectroscopy (l E ¼ 632 nm laser) further explored to characterize the ssDNA : MWNT hybridizations and the interactions with Hg 2 + ion as illustrated in Figure 4. In general, pristine graphite shows two distinct Raman features mainly [44], the G band due to strong CÀ C in-plane vibration appears around 1500 ~1600 cm À 1 (owing to E 1 2g symmetry), and the D band appears around 1300 ~1400 cm À 1 for out of plane breathing vibrational mode (A 1g symmetry) owing to the induced defects or damages to the hexagonal sp 2 networks [44]. Herein, for pristine MWNTs, the G and D bands observed at around 1568.3 cm À 1 and 1327.1 cm À 1 respectively (see Figure 4 hexagonal sp 2 network exploiting additional energy [45].…”