| Full text | |
| Author(s): |
Guilhon, I.
;
Bechstedt, F.
;
Botti, Silvana
;
Marques, M.
;
Teles, L. K.
Total Authors: 5
|
| Document type: | Journal article |
| Source: | PHYSICAL REVIEW B; v. 95, n. 24, p. 14-pg., 2017-06-23. |
| Abstract | |
We study the incomplete oxidation of graphene or reduction of graphene oxide for hydroxyl and epoxy oxidant groups. While in wet oxidation hydroxyl groups are favorable, in a drier environment an oxygen atom can bridge two neighboring carbon atoms. We model composition variations and structural disorder within a statistical theory, the generalized quasichemical approximation, combined with density functional theory calculations of the local atomic geometries. A generalization of the statistical approach is developed to account for the antiparallel orientation of hydroxyl groups and a fourfold coordination of C atoms. The theoretical framework enables a thermodynamic treatment of graphene oxide as a function of oxygen content, allowing us to derive temperature-composition phase diagrams and investigate possible clustering and segregation. The resulting geometries, local and average electronic structures, and optical absorption spectra are discussed and compared with available experimental data. (AU) | |