•The dispersion of graphene in alcohol solvents was investigated using DFT-D method.•The dispersion was evaluated by the binding energy of graphene and solvent molecule.•The binding energy increased linearly with alcohol from methanol to 1-pentanol.•The weak interaction was graphically shown by the reduced density gradient method.The dispersion of graphene in five different alcohol solvents was investigated by evaluating the binding energy between graphene and alcohol molecules using DFT-D method. The calculation showed the most stable binding energy appeared at the distance of ∼3.5 Å between graphene and alcohol molecules and increased linearly as changing the alcohol from methanol to 1-pentanol. The weak interaction was further graphically illustrated using the reduced density gradient method. The theoretical study revealed alcohols with more carbon atoms could be a good starting point for screening suitable solvents for graphene dispersion.Download high-res image (91KB)Download full-size image

Highlights•We investigate a new waveguide of a two-layer silver film with angled holes.•Light can propagate along opposite directions at different resonant wavelengths.•The propagation dimension can be as small as 10 nm.Using the discrete dipole approximation (DDA) method, we investigated the propagation of light within the visible wavelength region for a two-layer silver film with periodic angled holes. The perforation of the holes at an angle of 45° allows light to propagate selectively along different directions at two resonance wavelengths. The Poynting vector calculations show that light propagating along the direction of hole perforation at shorter wavelengths is due to the coupling between periodic holes, while the other one along the opposite direction at longer wavelengths is related to the coupling between the top and bottom layers in the film.Graphical abstract