Nanotomy-based production of transferable and dispersible graphene nanostructures of controlled shape and size

Abstract

Because of the edge states and quantum confinement, the shape and size of graphene nanostructures dictate their electrical, optical, magnetic and chemical properties. The current synthesis methods for graphene nanostructures do not produce large quantities of graphene nanostructures that are easily transferable to different substrates/solvents, do not produce graphene nanostructures of different and controlled shapes, or do not allow control of Gn dimensions over a wide range (up to 100 nm). Here we report the production of graphene nanostructures with predetermined shapes (square, rectangle, triangle and ribbon) and controlled dimensions. This is achieved by diamond-edge-induced nanotomy (nanoscalecutting) of graphite into graphite nanoblocks, which are then exfoliated. our results show that the edges of the produced graphene nanostructures are straight and relatively smooth with an I D /I G of 0.22-0.28 and roughness < 1 nm. Further, thin films of Gn-ribbons exhibit a bandgap evolution with width reduction (0, 10 and ~35 meV for 50, 25 and 15 nm, respectively).

Large-scale solution synthesis of narrow graphene nanoribbons

“…Thus, optical and photoluminescence data confirm a significant structural difference between products 3, 4 and 5. Figure 2b illustrates structural transformations that occur by cyclodehydrogenation of polymer 4 to form GNRs 5, as observed by 13 C NMR. In polymer 4 the solid state 13 C spectrum shows two groups of resonances: one at 140 p.p.m.…”

“…Theoretical studies predict a bandgap comparable to that in silicon (1.1 eV) in narrow graphene nanoribbons (GNRs) that have atomically precise armchair edges and widths o2 nm (refs 4,5). Different top-down fabrication approaches, such as nanofabrication 6,7 , sonochemical method 8 , nanowire lithography 9,10 , nanoscale cutting of graphene using nickel nanoparticles 11,12 or a diamond knife 13 and unzipping of carbon nanotubes [14][15][16][17][18][19] , typically yield ribbons with width 410 nm and have limited control over their edge structure. Although several groups demonstrated that such GNRs could exhibit an insulating state in electrical measurements, it was later argued that the observed transport bandgaps of up to B200-400 meV (refs 7-9) are likely to be caused by strong localization effects due to edge disorder, rather than a true gap between valence and conduction bands [20][21][22] .…”

The New Graphene Family Materials: Synthesis and Applications in Oxygen Reduction Reaction

“…Usually, the GNRs can be obtained by unzipping CNTs [34,[59][60][61][62][63], cutting graphene [64][65][66] and cracking graphite [67,68]. Among them, employing the CNTs as the source to get the GNRs is mostly used in the literature because of the mature and large-scale availability of CNTs.…”

“…When the 3D graphite is used, the thickness and the width should all be decreased. A so-called diamond-edge-induced nanoscale cutting method was applied to produce the GNRs by Mohanty et al [68]. Firstly, the graphite nano-blocks with a certain width were obtained by cutting along the direction perpendicular to the graphitic planes of the highly oriented pyrolytic graphite (HOPG).…”

Strain-dependent conductivity in biased bilayer graphene

“…(9) one sees that short, thick beams are preferable. For a BLG ribbon with L x = 100 nm and L y = 25 nm (which is experimentally achievable 30 ) and the thickness taken to be L z = 7Å, twice the thickness of monolayer graphene 31 …”