Atomically resolved imaging of highly ordered alternating fluorinated graphene

摘要

One of the most desirable goals of graphene research is to produce ordered two-dimensional (2D) chemical derivatives of suitable quality for monolayer device fabrication. Here we reveal, by focal series exit wave reconstruction (EWR), that Csub2/subF chair is a stable graphene derivative and demonstrates pristine long-range order limited only by the size of a functionalized domain. Focal series of images of graphene and Csub2/subF chair formed by reaction with XeFsub2/sub were obtained at 80?kV in an aberration-corrected transmission electron microscope. EWR images reveal that single carbon atoms and carbon–fluorine pairs in Csub2/subF chair alternate strictly over domain sizes of at least 150?nmsup2/sup with electron diffraction indicating ordered domains ≥0.16?μmsup2/sup. Our results also indicate that, within an ordered domain, functionalization occurs on one side only as theory predicts. In addition, we show that electron diffraction provides a quick and easy method for distinguishing between graphene, Csub2/subF chair and fully fluorinated stoichiometric CF 2D phases.