文档介绍：NATURE CHEMISTRY | VOL 2 | DECEMBER 2010 | urechemistry 1015 Graphene oxide as a chemically tunable platform for optical applications Kian Ping Loh 1 *, Qiaoliang Bao 1 , Goki E da 2 and M anish Chhowalla 2,3 * Chemically derived graphene oxide (GO) is an atomically thin sheet of graphite that has traditionally served as a precursor for graphene, but is increasingly attracting chemists for its own characteristics. It is covalently decorated with oxygen-containing functional groups — either on the basal plane or at the edges — so that it contains a mixture of sp 2- and sp 3-hybridized carbon atoms. In particular, manipulation of the size, shape and relative fraction of the sp 2-hybridized domains of GO by reduction chemistry provides opportunities for tailoring its optoelectronic properties. For example, as-synthesized GO is insulating but controlled deoxidation leads to an electrically and optically active material that is transparent and conducting. Furthermore, in contrast to pure graphene, GO is fluorescent over a broad range of wavelengths, owing to its heterogeneous electronic structure. In this Review, we highlight the recent advances in optical properties of chemically derived GO, as well as new physical and biological applications. T he exfoliation of graphite oxide — a material first discovered by the Oxford chemist Benjamin Brodie in 1859 — produces atomically thin graphene oxide sheets that are dispersible in basic media 1. Graphene oxide can be considered as the insulating and disordered analogue of the highly conducting crystalline graph - ene. The latter has attracted the interest of physicists because of its unique electronic structure with linear dispersion of Dirac elec - trons. The insulating and defective nature of GO does not allow the observation of fundamental two-dimensional condensed-matter effects, which has limited the interest of physicists in the material. Chemists, however, are increasingly drawn t