UC Riverside

Graphene is a single layer of carbon atoms densely packed in a two-dimensional (2D) sp2 -bonded carbon hexagonal lattice and is considered as an essential structure element for a variety of carbon materials. Graphene oxide (GO) is chemically modified graphene containing oxygen functional groups and has conventionally served as a precursor for graphene synthesis. Recently GO has received much more attention by scientists for its unique chemical and electrical properties. For example, when covalently functionalized with oxygen-containing functional groups both on the basal plane and at the edges, GO has an assortment of sp2- and sp3-hybridized carbon atoms. Hence, the availability of numerous types of oxygen-containing functional groups lets GO react with a great range of organic and inorganic materials in covalent, non-covalent or ionic methods so that functional hybrids and composites with remarkable properties can be likely synthesized. Chemically treating a variety of size, shape and relative fractions of sp2-hybridized domains of GO becomes a powerful approach for application-purposed design and preparation of functionalized carbon materials for its optoelectronic characteristics1-3. Furthermore, compared with pristine graphene, GO is fluorescent over a broad range of wavelengths, because of its mixed electronic structures3-5. The objectives of this work is to design of a graphene-based device with reversibly controllable graphene/graphene oxide ratio through chemical and electrical approaches.