Structural analysis of polycrystalline graphene systems by Raman spectroscopy

Abstract

A theoretical model supported by experimental results explains the dependence of the Raman scattering signal on the evolution of structural parameters along the amorphization trajectory of polycrystalline graphene systems.Four parameters rule the scattering efficiencies, two structural and two related to the scattering dynamics. With the crystallite sizes previously defined from X-ray diffraction and microscopy experiments, the three other parameters (the average grain boundaries width, the phonon coherence length, and the electron coherence length) are extracted from the Raman data with the geometrical model proposed here. The broadly used intensity ratio between

Absorption of calcium ions on oxidized graphene sheets and study its dynamic behavior by kinetic and isothermal models

“…The spectra are for microcrystalline celluloses (cellulose powder, Aldrich) from rice straw as an example of different proportions of crystalline cellulose. This would suggest that microcrystalline cellulose contains a higher crystalline cellulose (Ribeiro-Soares et al 2015).…”

A Guide to and Review of the Use of Multiwavelength Raman Spectroscopy for Characterizing Defective Aromatic Carbon Solids: from Graphene to Amorphous Carbons

“…The ability of Raman spectroscopy to study these properties is presented in the work by Ferrari and Basko [62]. Jorio, Cançado, and Lucchese et al, in a series of papers [97][98][99][100][101][102], were able to characterize and distinguish the influence of 0D and 1D defects on graphene. Venezuela et al published a theoretical paper in 2011 [69] in which they calculated the double resonant Raman spectra of defective graphene, and reproduced the dispersion of D, D', 2D bands and weaker ones (which are combination bands but not necessarily, some bands being attributed to acoustic branches).…”

“…One can see that the I D /I D' ratio strongly depends on the C S,D' coefficient, which is found to be equal to 0.1 for sp 3 defects whereas it is 1.2 for vacancy defects. Ribeiro-Soares et al studied 1D defects in graphene [102]. They heated a diamond-like carbon from 1200 to 2800 • C. They obtained an expression for the I D /I G intensity ratio [102], by noting that two sets of two bands have to be considered: A first set of D and G bands occurring from the activated region, and one set of D and G bands, downshifted due to softening of the phonon modes, occurring from highly disordered areas.…”

“…Ribeiro-Soares et al studied 1D defects in graphene [102]. They heated a diamond-like carbon from 1200 to 2800 • C. They obtained an expression for the I D /I G intensity ratio [102], by noting that two sets of two bands have to be considered: A first set of D and G bands occurring from the activated region, and one set of D and G bands, downshifted due to softening of the phonon modes, occurring from highly disordered areas. Let us thus consider a structurally damaged ribbon (width l S ), and activated region (width l A ) and the mean size of a crystallite L a (see Figure 17b).…”

“…Creating point defects [101] and/or linear defects [97,102] and controlling their influence on the Raman spectrum of graphene have been the milestones of a bottom-up approach aiming at understanding the Raman spectra of more complex aromatic carbons. It has been one of the best progresses made over the last few years in order to overcome the old Tuinstra and Ferrari relations that were found to give more or less the order of magnitude/trends.…”