Optical properties of two-dimensional zigzag and armchair graphyne nanoribbon semiconductor.

Optical properties of zigzag and armchair graphyne nanoribbon (GNR) sheet were investigated. Effect of increasing the width of nanoribbon on optical properties and optical band gap in particular was also studied. Calculations were based on density functional theory (DFT) and the results showed that these structures were semiconductors with the optical band gap of about 1-3.5 eV; this value was higher than for the armchair than zigzag structures. With increasing the width of the ribbons, optical band gap decreased in both structures and maximum electron energy loss spectroscopy (EELS) and dielectric constant increased for the zigzag and armchair structures. Moreover, for the armchair structure, maximum optical reflectivity versus GNR width was a linear function, while it showed a teeth behavior for the zigzag structure.