Graphene has been attracting great interest because of its distinctive band structure and physical properties. Today, graphene is limited to small sizes because it is produced mostly by exfoliating graphite. We grew large-area graphene films of the order of centimeters on copper substrates by chemical vapor deposition using methane. The films are predominantly single-layer graphene, with a small percentage (less than 5%) of the area having few layers, and are continuous across copper surface steps and grain boundaries. The low solubility of carbon in copper appears to help make this growth process self-limiting. We also developed graphene film transfer processes to arbitrary substrates, and dual-gated field-effect transistors fabricated on silicon/silicon dioxide substrates showed electron mobilities as high as 4050 square centimeters per volt per second at room temperature.

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Graphene sheets--one-atom-thick two-dimensional layers of sp2-bonded carbon--are predicted to have a range of unusual properties. Their thermal conductivity and mechanical stiffness may rival the remarkable in-plane values for graphite (approximately 3,000 W m(-1) K(-1) and 1,060 GPa, respectively); their fracture strength should be comparable to that of carbon nanotubes for similar types of defects; and recent studies have shown that individual graphene sheets have extraordinary electronic transport properties. One possible route to harnessing these properties for applications would be to incorporate graphene sheets in a composite material. The manufacturing of such composites requires not only that graphene sheets be produced on a sufficient scale but that they also be incorporated, and homogeneously distributed, into various matrices. Graphite, inexpensive and available in large quantity, unfortunately does not readily exfoliate to yield individual graphene sheets. Here we present a general approach for the preparation of graphene-polymer composites via complete exfoliation of graphite and molecular-level dispersion of individual, chemically modified graphene sheets within polymer hosts. A polystyrene-graphene composite formed by this route exhibits a percolation threshold of approximately 0.1 volume per cent for room-temperature electrical conductivity, the lowest reported value for any carbon-based composite except for those involving carbon nanotubes; at only 1 volume per cent, this composite has a conductivity of approximately 0.1 S m(-1), sufficient for many electrical applications. Our bottom-up chemical approach of tuning the graphene sheet properties provides a path to a broad new class of graphene-based materials and their use in a variety of applications.

The chemistry of graphene oxide is discussed in this critical review. Particular emphasis is directed toward the synthesis of graphene oxide, as well as its structure. Graphene oxide as a substrate for a variety of chemical transformations, including its reduction to graphene-like materials, is also discussed. This review will be of value to synthetic chemists interested in this emerging field of materials science, as well as those investigating applications of graphene who would find a more thorough treatment of the chemistry of graphene oxide useful in understanding the scope and limitations of current approaches which utilize this material (91 references).

Due to an oversight of the editorial office, a mistake was introduced in the references on page 3919, right column, at the start of the fourth paragraph. In the published paper the text segment on page 3919 reads: As mentioned, graphene can be grown on metal surfaces by surface segregation of carbon or by decomposition of hydrocarbons. However, this technique is only practical for graphene production if the as-grown graphene can be transferred from the metal substrates to other substrates, which looks straightforward but only was realized for multilayer and non-uniform films recently with Ni [160-162] and for uniform monolayer graphene, with Cu. [17] However, reference 160 does not relate to graphene segregation on metal surfaces. The authors first to report this technique were Qingkai Yu and co-workers as described in reference 246. Consequently, the start of the fourth paragraph on page 3919 should be corrected to read as follows: As mentioned, graphene can be grown on metal surfaces by surface segregation of carbon or by decomposition of hydrocarbons. However, this technique is only practical for graphene production if the as-grown graphene can be transferred from the metal substrates to other sub-strates, which looks straightforward but only was realized for multilayer and non-uniform films recently with Ni, [246,161,162] and for uniform monolayer graphene, with Cu. [17] The editorial office apologizes for any inconvenience caused. In addition, reference 160 was not published in 2009, so reference 160 should read: [160] J.