Provided herein are graphene nanoribbons with high structural uniformity and low levels of impurities and methods of synthesis thereof. Also provided herein are graphene nanoplatelets of superior structural uniformity and low levels of impurities and methods of synthesis thereof. Further provided herein are mixtures of graphene nanoribbons and graphene nanoplatelets of good structural uniformity and low levels of impurities and methods of synthesis thereof. The method includes, for example, the steps of depositing catalyst on a constantly moving substrate, forming carbon nanotubes on the substrate, separating carbon nanotubes from the substrate, collecting the carbon nanotubes from the surface where the substrate moves continuously and sequentially through the depositing, forming, separating and collecting steps. Further processing steps convert the synthesized carbon nanotubes to graphene nanoribbons, graphene nanoplatelets and mixtures thereof.

The Present teachings provide, in part, methods of separating two-dimensional nanomaterials by atomic layer thickness. In certain embodiments, the present teachings provide methods of generating graphene nanomaterials having a controlled number of atomic layer(s).

A method for making a graphene nanoribbon composite structure includes providing a substrate including a plurality of protrusions spaced apart from each other. A graphene film is grown on a growth substrate, an adhesive layer is on a surface of the graphene film away from the growth substrate. After removing the growth substrate, the graphene film and the adhesive layer are cleaned with water or an organic solvent. The graphene film, the adhesive layer, and the substrate are combined and then are dried, so that a plurality of wrinkles are formed near the plurality of protrusions. The adhesive layer is removed, and after etching a surface of the graphene film away from the substrate, the graphene films except for the plurality of wrinkles are removed, to form a plurality of graphene nanoribbons.

Methods of transferring nanostructures from a first substrate to another substrate using a copolymer polymerized from one or more non-crosslinking monomers and one or more comonomers bearing crosslinkable groups as a transfer medium are provided. Relative to a poly(methyl methacrylate) homopolymer, the crosslinkable copolymers bond more strongly to the first substrate and, as a result, are able to transfer even very narrow nanostructures between substrates with high transfer yields.

This invention in one aspect relates to a method of synthesizing a self-assembled mixed-dimensional heterostructure including 2D metallic borophene and 1D semiconducting armchair-oriented graphene nanoribbons (aGNRs). The method includes depositing boron on a substrate to grow borophene thereon at a substrate temperature in an ultrahigh vacuum (UHV) chamber; sequentially depositing 4,4-dibromo-p-terphenyl on the borophene grown substrate at room temperature in the UHV chamber to form a composite structure; and controlling multi-step on-surface coupling reactions of the composite structure to self-assemble a borophene/graphene nanoribbon mixed-dimensional heterostructure. The borophene/aGNR lateral heterointerfaces are structurally and electronically abrupt, thus demonstrating atomically well-defined metal-semiconductor heterojunctions.

Disclosed herein are graphene nanoribbons, controllable and reproducible methods of synthesizing graphene nanoribbons, and uses thereof. Transistors containing graphene nanoribbons are also disclosed.

The present invention relates to a segmented graphene nanoribbon, comprising at least two different graphene segments covalently linked to each other, each graphene segment having a monodisperse segment width, wherein the segment width of at least one of said graphene segments is 4 nm or less and to a method for preparing it by polymerizing at least one polycyclic aromatic monomer compound and/or at least one oligo phenylene aromatic hydrocarbon monomer compound to form at least one polymer and by at least partially cyclodehydrogenating the one or more polymer.

A GNR is a ribbon-shaped graphene film which includes: five or more (for example, five, seven, or nine) six-membered rings of carbon atoms which are bonded and arranged in line in a short side direction; and a complete armchair type edge structure along a long side direction. By such a constitution, without using a transfer method, there are materialized a highly reliable graphene film which has an armchair type edge structure with a uniform width at a desired value and which enables an electric current on-off ratio of 10.sup.5 or more that is practically sufficient for exhibiting a desired band gap.

Embodiments of the present disclosure pertain to methods of making electrically conductive materials by applying nanowires and graphene nanoribbons onto a surface to form a network layer with interconnected graphene nanoribbons and nanowires. In some embodiments, the methods include the following steps: (a) applying graphene nanoribbons onto a surface to form a graphene nanoribbon layer; (b) applying nanowires and graphene nanoribbons onto the graphene nanoribbon layer to form the network layer; and (c) optionally applying graphene nanoribbons onto the formed network layer to form a second graphene nanoribbon layer on the network layer. Additional embodiments of the present disclosure pertain to the formed electrically conductive materials and their use as components of electronic devices, such as energy storage devices. Further embodiments of the present disclosure pertain to electronic devices that contain the electrically conductive materials of the present disclosure.

The present teachings provide, in part, methods of separating two-dimensional nanomaterials by atomic layer thickness. In certain embodiments, the present teachings provide methods of generating boron nitride nanomaterials having a controlled number of atomic layer(s).