Water structure and charge transfer phenomena at the liquid-graphene interface

Physicochemical properties of the graphene-water interface have been investigated to scrutinize the perturbations with respect to the graphene-air interface, in terms of changes in optical and vibrational spectra, as well as in the 3D network of water. Experimental investigations were carried out using Raman spectroscopy and laser scanning confocal microscopy, and integrated with density functional theory (DFT) calculations. Results evidence a substantial orientation of the hydrogen-bonded water molecules at the interfacial region, which, in turn, induces disorder in the water clusters and interfacial charge transfer phenomena. Water-induced graphene p-doping and preferential orientation of hydrogen-bonded water at the interface with graphene are demonstrated by comparative experimental (Raman spectroscopy and confocal microscopy) and theoretical (DFT) investigations.