ESR Spectroscopy of Graphene with Adsorbed NaCl Particles

Due to its peculiar properties graphene is a good candidate for sensor materials. Therefore, it is important to study influence of different fluids on graphene layer. The presented studies showed pinning of NaCl microcrystals to graphene surface after immersing graphene in NaCl solution and subsequent careful rinsing with distilled water. The atomic force microscopy images revealed presence of many NaCl-related structures over 100 nm high on graphene surface. The electron spin resonance spectrum for magnetic field perpendicular to the graphene layer consisted of several lines originating from NaCl. The pinning of NaCl microcrystals resulted in increase of electron scattering, as confirmed by the Raman spectroscopy (the increase of intensity of D and D' bands) and weak localization measurement (the decrease of coherence length).