Raman study on defective graphene: Effect of the excitation energy, type, and amount of defects

Abstract

We present a detailed Raman study of defective graphene samples containing specific types of defects. In particular, we compared sp 3 sites, vacancies, and substitutional Boron atoms. We find that the ratio between the D and G peak intensities, I(D)/I(G), does not depend on the geometry of the defect (within the Raman spectrometer resolution). In contrast, in the limit of low defect concentration, the ratio between the D and G peak intensities is higher for vacancies than sp 3 sites. By using the local activation model, we attribute this difference to the term C S,x , representing the Raman cross section of I(x)/I(G) associated with the distortion of the crystal lattice after defect introduction per unit of damaged area, where x = D or D. We observed that C S,D = 0 for all the defects analyzed, while C S,D of vacancies is 2.5 times larger than C S,D of sp 3 sites. This makes I(D)/I(D) strongly sensitive to the nature of the defect. We also show that the exact dependence of I(D)/I(D) on the excitation energy may be affected by the nature of the defect. These results can be used to obtain further insights into the Raman scattering process (in particular for the D peak) in order to improve our understanding and modeling of defects in graphene.

Water-soluble polyaniline/graphene composites as materials for energy storage applications

“…The Raman spectrum of GO has displayed two strong peaks at 1341 and 1602 cm -1 , corresponding to the D (is related to the presence of edges and defects in the sp 2 lattice, being absent for pure graphene monolayers) [40] and G bands (is related to sp 2 carbon network) [41], respectively and the intensity ratio I D /I G is approximately 0.97 (Figure 3)). A broad absorption above 2660 cm -1 is observed and is assigned to the 2D band and its presence suggests the existence of multilayers besides monolayers of graphene [42].…”

Raman spectroscopy study of the transformation of the carbonaceous skeleton of a polymer-based nanoporous carbon along the thermal annealing pathway

“…Of interest here are those that have been experimentally observed for disordered carbons and are thought to be related to defects, namely the D' [22,[30][31][32][33][34], A [35][36][37][38][39][40][41] and TPA [40][41][42] bands. Similar to the D band, the D' band is caused by defect-induced breaking of translational symmetry [32].…”

Synthesis of Carbon Nanowalls and Few-Layer Graphene Sheets on Transparent Conductive Substrates

“…For example, the D-and D -modes are so called disorder induced bands which cannot be seen in defect-free graphene or graphite at all. Basically the relative intensity of the D-mode correlates with the extension of the -conjugated system and hence increases with the amount of defects in the graphene structure, while the intensity of D -mode is even depending on the type of defect [35]. The G-mode is correlated to bond stretching vibrations between neighbor sp 2 carbon atoms [24], while the second order (G -or) 2D-mode is used to determine the number of layers in graphene [36].…”

“…The number of graphene layers can be estimated on the basis of the I 2D /I G -ratio, where a single graphene layer shows roughly a ratio of 4, while graphite and few-layer graphene shows much lower values [39]. Finally the I D /I D -ratio seems to depend on the nature of the defects in graphene [35].…”