Structural and electronic properties of oxidized graphene

Twist-boat conformation in graphene oxides

We have investigated the structural, electronic, and vibrational properties of graphene oxide based on first-principles density-functional calculations. A twist-boat conformation is identified as the energetically most favorable nonmetallic configuration for fully oxidized graphene. The calculated Raman G-band blue shift is in very good agreement with experimental observations. Our results provide important insight into structural and electronic characteristics that are useful for further development of graphene-based nanodevices.

Damaging graphene with ozone treatment: a chemically tunable metal-insulator transition

We present a multiscale ab initio study of electronic and transport properties of two-dimensional graphene after epoxide functionalization via ozone treatment. The orbital rehybridization induced by the epoxide groups triggers a strong intervalley scattering and changes dramatically the conduction properties of graphene. By varying the coverage density of epoxide defects from 0.1 to 4%, charge conduction can be tuned from a diffusive to a strongly localized regime, with localization lengths down to a few nanometers long. Experimental results supporting the interpretation as a metal-insulator transition are also provided.

Chemically derived graphene oxide: towards large-area thin-film electronics and optoelectronics

Chemically derived graphene oxide (GO) possesses a unique set of properties arising from oxygen functional groups that are introduced during chemical exfoliation of graphite. Large-area thin-film deposition of GO, enabled by its solubility in a variety of solvents, offers a route towards GO-based thin-film electronics and optoelectronics. The electrical and optical properties of GO are strongly dependent on its chemical and atomic structure and are tunable over a wide range via chemical engineering. In this Review, the fundamental structure and properties of GO-based thin films are discussed in relation to their potential applications in electronics and optoelectronics.

Engineering graphene by oxidation: a first-principles study

Graphene epoxide, with oxygen atoms lining up on pristine graphene sheets, is investigated theoretically here using first-principles calculations. Two distinct phases-metastable clamped and stable unzipped structures-are observed consistent with experimental observations. In the clamped structure, oxygen atoms form a regular lattice on the graphene sheet. In the unzipped phase, an epoxy group breaks the lower sp(2) bond and modifies the mechanical and electronic properties of graphene remarkably. The foldable epoxy ring structure reduces its Young's modulus by 42.4%, while leaving the tensile strength almost unchanged. The perturbation of epoxidation on the band structures depends on the density and symmetry of oxidation. These results pave the way for oxidation-based engineering of graphene-related materials.