On the Suitability of Raman Spectroscopy to Monitor the Degree of Graphene Functionalization by Diazonium Salts
journal contributionposted on 27.08.2019, 20:16 authored by Krishna Sampathkumar, Valentin Diez-Cabanes, Petr Kovaricek, Elena del Corro, Milan Bouša, Jan Hošek, Martin Kalbac, Otakar Frank
Raman spectroscopy is undoubtedly the most frequently used technique for universal characterization of graphene and related materials. Quantification of parameters like disorder or strain is possible through analysis of particular Raman bands. However, under certain conditions, such evaluation can be jeopardized bysometimes hiddenconvolution of more overlapping effects. In this work, graphene functionalization by the common nitrobenzenediazonium salt under simultaneous biaxial tensile deformation induced by substrate swelling was investigated by Raman spectroscopy. As expected, the disorder-related D band appeared in the spectra documenting the covalent attack on the graphene lattice. However, the strain-induced shift of the graphene bands exposed additional peaks, masked at exactly the same positions as the unstrained graphene bands. The new bands were assigned to vibrations of the diazonium molecule and its decomposition products adsorbed on top of the functionalized graphene. The external strain thus provided means for more correct quantification of the lattice disorder.
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Graphene Functionalizationcovalent attackdiazonium moleculedecomposition productsgraphene bandsdisorder-related D bandDiazonium Salts Raman spectroscopygraphene latticegraphene functionalizationRaman spectroscopylattice disorderunstrained graphene bandsRaman Spectroscopyfunctionalized graphenestrain-induced shiftnitrobenzenediazonium saltRaman bands