How Reliable Are Raman Spectroscopy Measurements of Graphene Oxide?

Abstract

Graphene oxide (GO) has garnered attention for its tunable chemical, electrical, and optical properties. An integral part of the efforts to manipulate and improve the performance of GO is the ability to reliably characterize its complex structure. Raman spectroscopy and confocal Raman mapping are widely used for insight into the extent of GO’s nanoscale graphene-like domains, the degree of lattice order, and its sheet stacking structure. It has also been reported, however, that laser sources, similar to those used for Raman spectroscopy, can be used to intentionally reduce and ablate GO. In light of this, it is unclear how invasive Raman measurements of GO are and how reliable published Raman data is. In this study, we employ Raman laser doses spanning 4 orders of magnitude to investigate the impact of Raman measurements on GO structure. We find that GO undergoes reduction at all practical laser doses, with the degree of reduction increasing with dose. Lattice damage and ablation dominate at high laser doses. Based on our findings, we encourage the use of a minimal laser dose (8 × 10 7 J/m 2 or below) for Raman measurements of GO. Despite the resulting loss in signal, these conditions limit sample modification and measurement inaccuracies.