Vibrational Signatures of Carboxylated Graphene: a Computational Study

Abstract

Raman and infrared (IR) spectroscopies are fast, efficient, and nondestructive techniques commonly used for structural characterization of carbon nanomaterials. Using computational methods based on density functional theory, we computed the vibrational Raman and IR absorption spectra of carboxylated graphene containing no surface defects, containing Stone?Wales defects, and containing divacancies. Our calculations demonstrated that the presence of point defects near the functionalization sites significantly altered the Raman and IR spectra of carboxylated graphene. In all cases, we observed the emergence of new Raman and IR absorption bands in the range of low and high frequencies. The calculated Raman and IR spectra showed clearly distinguishable spectroscopic signatures associated to different types of structural defects present in carboxylated graphene. The results of our study provide guidelines for the interpretation of Raman and IR spectra of chemically functionalized graphene.