Patterned Partially Hydrogenated Graphene (C₄H) and Its One-Dimensional Analogues: A Computational Study

By means of density functional theory (DFT) computations, we systematically studied the structural and electronic properties of the experimentally just achieved new two-dimensional (2D) hydrocarbon — the patterned partially hydrogenated graphene with formula C 4 H ( Adv. Mater 2011, 23, 4497), and in particular its one-dimensional (1D) analogues. The C 4 H layer is a stable 2D crystal featured with periodic Clar sextet aromatic rings and is semiconducting with a wide band gap; however, this single-sided patterned partially hydrogenated C 4 H layer can only be obtained when the possibility of double-sided hydrogenation is excluded, since the double-sided graphane-embedded structure is energetically more favorable. The 1D C 4 H nanotubes, rolled up by the C 4 H layer, exhibit excellent thermodynamic properties and all have a wide band gap regardless of the tube diameter and chirality. In contrast, cutting the C 4 H layer into 1D C 4 H nanoribbons can result in rich electronic characteristics: they can be metallic or semiconducting depending on the chirality and edge configuration.