Band gaps and structural properties of graphene halides and their derivates: A hybrid functional study with localized orbital basis sets

Abstract

DFT calculations of the electronic structure of graphane and stoichiometrically halogenated graphene derivatives (fluorographene and other analogous graphene halides) show (i) localized orbital basis sets can be successfully and effectively used for such 2D materials; (ii) several functionals predict that the band gap of graphane is greater than that of fluorographene, whereas HSE06 gives the opposite trend; (iii) HSE06 functional predicts quite good values of band gaps w.r.t benchmark theoretical and experimental data; (iv) the zero band gap of graphene is opened by hydrogenation and halogenation and strongly depends on the chemical composition of mixed graphene halides; (v) the stability of graphene halides decreases sharply with increasing size of the halogen atom -fluorographene is stable, whereas graphene iodide spontaneously decomposes. In terms of band gap and stability, the C 2 FBr, and C 2 HBr derivatives seem to be promising materials, e.g., for (opto)electronics applications, because their band gaps are similar to those of conventional semiconductors, and they are expected to be stable under ambient conditions. The results indicate that other fluorinated compounds (C a H b F c and C a F b Y c , Y = Cl, Br, I) are stable insulators.

Towards a better understanding of the geometrical and orientational aspects of the electronic structure of halogens (F–I) adsorption on graphene

“…Our last verification is that this calculation method has been verified for fluorographene case with excellent agreement with previous studies in terms of DOS and band gap [3,17] (Fig. S3 in supplementary data).…”

Ab initiostudies of isolated boron substitutional defects ingraphane

“…The valence band maximum (VBM) and conduction band minimum (CBM) are separated by a band gap of 3.35 eV. This band gap value is in good agreement with the values previously reported in Refs [2,3,23,24,25] revealing that graphane is a wide band gap semiconductor. All the DOS plots show that the B doped graphane systems are non-magnetic, even if the spin is imposed before the calculations they turn out to be non-spin polarized after relaxation.…”

One-step synthesis of chlorinated graphene by plasma enhanced chemical vapor deposition

“…Inside, the covalent modification of graphene is much reliable to apply in the future electronic device, in contrast with the physisorption of chemical species. Graphene halide [4,5], one of graphene derivative including fluoride [6,7], chloride [8,9], bromide [10][11][12] and iodide [12,13], have been recently investigated for the band gap engineering. Among them, graphene chloride is a p-doping type covalent modification of graphene which could tailor the intrinsic properties of graphene [14,15].…”