First-principles study of hydrogenated graphyne and its family: Stable configurations and electronic structures

Graphyne is a new two-dimensional carbon allotrope consisting of sp- and sp(2)-hybridized carbon atoms. We performed first-principles calculations to study the stable configurations and the corresponding electronic structures of hydrogenated graphyne and its family. We found that at low coverage, hydrogen atoms prefer to chemically adsorb on the carbon atoms in the chains rather than on those in the hexagons. The hydrogen adsorption on graphyne is stronger than that on graphene. The band gap of hydrogenated graphyne is tunable in a wide range upon changing the hydrogen coverage. This implies a promising route to tune the electronic properties of graphyne and its family via attaching foreign atoms or functional groups into its scaffolding. (C) 2012 Elsevier B.V. All rights reserved.