Surface enhanced infrared absorption spectroscopy for graphene functionalization on copper

Abstract

The monolayer form of CVD graphene is imposing crucial challenges in characterization of the targeted covalent functionalization due to the low amount of grafting moieties on the surface, which in turn hampers drawing conclusions about reactivity-properties relationships. Due to the growing interest in chemically modified graphene new, reliable and non-destructive methods for its characterization are critically required. Herein we demonstrate the use of surface-enhanced infrared absorption spectroscopy for detection of characteristic vibration modes of species being grafted to the material either via radical (Meerwein arylation) or nucleophilic substitution pathway on copper foil. The phenomenon is allowed by the appropriate metal surface morphology and no signal could have been obtained neither on Si/SiO2 substrate, nor on bare copper. The surface of copper foil exhibit partial corrosion during the reaction which leads to the creation of active substrate for SEIRA. The measurements were performed using reflection-absorption and attenuated total reflection modes with almost identical results, thus making this analytical approach feasible, practical, non-destructive and easy to use for routine characterization of graphene functionalization.