115 results about "Monolayer graphene" patented technology

Disclosed are a graphene composite nanofiber and a preparation method thereof. The graphene composite nanofiber is produced by dispersing graphenes to at least one of a surface and inside of a polymer nanofiber or a carbon nanofiber having a diameter of 1˜1000 nm, and the graphenes include at least one type of monolayer graphenes, and multilayer graphenes having a thickness of 10 nm or less. The graphene composite nanofiber can be applied to various industrial fields, e.g., a light emitting display, a micro resonator, a transistor, a sensor, a transparent electrode, a fuel cell, a solar cell, a secondary cell, and a composite material, owing to a unique structure and property of graphene.

The present invention provides for a one or more layer graphene optical modulator. In a first exemplary embodiment the optical modulator includes an optical waveguide, a nanoscale oxide spacer adjacent to a working region of the waveguide, and a monolayer graphene sheet adjacent to the spacer. In a second exemplary embodiment, the optical modulator includes at least one pair of active media, where the pair includes an oxide spacer, a first monolayer graphene sheet adjacent to a first side of the spacer, and a second monolayer graphene sheet adjacent to a second side of the spacer, and at least one optical waveguide adjacent to the pair.

The invention discloses a method for rapidly preparing monolayer graphene oxide through a one-pot method. The method comprises the following steps: stirring, mixing and infiltrating graphite and concentrated acid or the mixed acid of the graphite and concentrated acid for 5 min to 1h at 20-50 DEG C, adding a strong oxidant and an intercalator for intercalating, slowly heating a mixed solution to 30-100 DEG C, and consistently stirring for 1-10 h; cooling a reaction solution to 20-37 DEG C, supplementing a certain amount of the concentrated acid or the mixed acid of the graphite and concentrated acid, slowly adding the strong oxidant, reacting for 0.5-3 h at 20-37 DEG C, heating to the temperature which is 10 DEG C lower than a safe temperature, further reacting for 2-8 h for oxidizing and stripping a graphite sheet layer, after completion of reaction, slowly pouring an obtained product into icy deionized water for diluting, adding hydrogen peroxide after the icy deionized water is stable, performing standing, cleaning precipitate with 1mol/L of dilute hydrochloric acid and deionized water repeatedly, and centrifuging to obtain the monolayer graphene oxide. The method is simple and controllable in preparation process and short in time consumption and low in energy consumption; by the one-pot method, the grapheme can be rapidly and directly converted to the monolayer graphene oxide.

The invention discloses a graphene oxide/hyaluronic acid nanometer drug carrier material. The graphene oxide/hyaluronic acid nanometer drug carrier material is characterized in that adipic acid hydrazide is covalently connected on the surface of monolayer graphene oxide, targeted molecular hyaluronic acid is further coupled by amino groups on the adipic acid hydrazide; the monolayer graphene oxide is 0.5-2nm thick; and the average size of the graphene oxide/hyaluronic acid nanometer drug carrier material is 50-300nm. According to the graphene oxide/hyaluronic acid nanometer drug carrier material provided by the invention, the hyaluronic acid is covalently modified on the surface of the graphene oxide and has a good targeting property; besides, the modified graphene oxide has good biocompatibility and benefits the biological application of the material; and moreover, the obtained functionalized nanometer material is expected to be used as a drug transmission carrier.

The invention discloses a pollution-free low-cost technology for preparing graphene oxide. The technology comprises the following steps: 1, mixing graphite with a strong acid to infiltrate graphite, adding a strong oxidant, and continuously stirring to oxidize and exfoliate graphite layers; 2, centrifuging the obtained reaction solution, recovering the strong acid to be used in a next reaction, slowly pouring the obtained muddy product into deionized water, stirring, washing by using dilute hydrochloric acid, repeatedly cleaning by using deionized water, and centrifuging to obtain monolayer graphene oxide; 3, introducing ammonia gas into wastewater until the pH value approaches 7 to obtain an inorganic fertilizer containing nitrogen, potassium, iron and phosphorus; and 4, concentrating an aqueous solution of graphene oxide, and drying to obtain graphene oxide with high density and high specific surface area. The technology has the advantages of simple, safe and controllable preparation process, less time and energy consumption, no explosion danger and no pollution. The cycle use of concentrated sulfuric acid in the raw material-to-fertilizer process makes all raw materials and elements fully used, so the preparation cost of graphene oxide is greatly reduced.

Disclosed are graphene shield enhanced photocathodes, such as high QE photocathodes. In certain embodiments, a monolayer graphene shield membrane ruggedizes a high quantum efficiency photoemission electron source by protecting a photosensitive film of the photocathode, extending operational lifetime and simplifying its integration in practical electron sources. In certain embodiments of the disclosed graphene shield enhanced photocathodes, the graphene serves as a transparent shield that does not inhibit photon or electron transmission but isolates the photosensitive film of the photocathode from reactive gas species, preventing contamination and yielding longer lifetime.

The invention discloses a method for preparing biocompatible graphite, comprising the steps of: ultrasonically dispersing prepared graphite oxide to obtain a graphene oxide solution, uniformly mixing the graphene oxide solution as well as sulfydryl-containing amino acid and a derivative thereof, placing the mixture in an oil bath for reaction for a certain time to obtain a graphene product, and carrying out vacuum filtration on the product to obtain the monolayer graphene with dispersion stability. The method has the advantages of simple technological conditions, no toxin and environmental-protection performance, and the prepared graphene can stably disperse in an aqueous solution, presents favorable biocompatibility, and has an excellent property when being used as a super capacitor electrode material.

The present invention relates to a method for producing graphene on a face-centered cubic metal catalyst having a plane oriented in one direction, and more particularly to a method of producing graphene on a metal catalyst having the (100) or (111) crystal structure and a method of producing graphene using a catalyst metal foil having a single orientation, obtained by electroplating a metal catalyst by a pulse wave current and annealing the metal catalyst. The invention also relates to a method of producing graphene using a metal catalyst, and more particularly to a method of producing graphene, comprising the steps of: alloying a metal catalyst with an alloying element; forming step structures on the metal catalyst substrate in an atmosphere of a gas having a molecular weight of carbon; and supplying hydrocarbon and hydrogen gases to the substrate. On unidirectionally oriented metal catalyst prepared according to the present invention, graphene can be grown uniformly and epitaxially. Moreover, a method for producing graphene according to the present invention can form monolayer graphene by epitaxially growing graphene while increasing the growth rate of graphene.

The invention provides a hard disc device, comprising a magnetic head and a disc body, wherein the magnetic head and the disc body are provided with low-friction atomic scale smooth surfaces; and each low-friction atomic scale smooth surface comprises monolayer graphene, molybdenium disulfide, bismuth, molybdenum, mica and the like. Vander wale force between the low-friction atomic scale smooth surfaces is used as soft support, thus greatly reducing the distance of the magnetic head and the disc body, correspondingly improving the storage density of a magnetic disc, and being capable of realizing contact reading and writing to a hard disc. Simultaneously, due to the extreme low friction coefficient between the atomic scale smooth surfaces, the extreme high rotating speed can be easily realized, so the reading and writing speed of data of the hard disc can be improved. In addition, the hard disc device can well solve the defects of the traditional hard disc in the aspects of high-low temperature resistance, vibration resistance, shock resistance and the like, and greatly improves the stability of the hard disc.

The present invention relates to a large-area single-crystal monolayer graphene film in which a graphene layer is formed on a single-crystal metal catalyst layer whose crystal plane orientation is (111) optionally on a substrate. In the large-area single crystal monolayer graphene film of the present invention, a single-crystal metal catalyst layer whose crystal plane orientation is (111) can be formed in the shape of a foil, plate, block or tube optionally on a substrate and a graphene layer is formed on the catalyst layer. The present invention also relates to a method for producing a large-area single-crystal monolayer graphene film whose crystal plane orientation is (111) by annealing and chemical vapor deposition of a metal precursor. According to the method of the present invention, a high-quality large-area graphene thin film applicable as a material for transparent electrodes, display devices, semiconductor devices, separation membranes, fuel cells, solar cells, and sensors can be produced on a commercial scale.

The invention discloses a broadband absorber based on a double-ring structure of graphene. With metal as a reflective substrate, an insulating dielectric layer and a graphene layer are above the reflective substrate in order. The graphene layer is formed by a periodic monolayer graphene double-ring structure. Since the graphene exhibits strong metallicity in infrared and terahertz bands, a graphene structure is directly used as a resonant structural unit, a strong resonance coupling between graphene nanostructures realizes a single-layer broadband absorber, and the processing process of the structure is greatly simplified. Because of the unique electrical properties of the graphene, a chemical potential and a surface conductivity can be changed by the change of applied bias voltage, and the absorption frequency range of an absorbing structure is regulated. The broadband absorber has the advantages of a simple structure and high absorption efficiency and has important application prospects in the fields of terahertz imaging, sensing, a continuous light source and the like.

A scalable process for fabricating graphene/hexagonal boron nitride (h-BN) heterostructures is disclosed herein. The process includes (BN)_XH_y-radical interfacing with active sites on silicon nitride coated silicon (Si₃N₄/Si) surfaces for nucleation and growth of large-area, uniform and ultrathin h-BN directly on Si₃N₄/Si substrates (B/N atomic ratio=1:1.11±0.09). Further, monolayer graphene van der Waals bonded with the produced h-BN surface benefits from h-BN's reduced roughness (3.4 times) in comparison to Si₃N₄/Si. Because the reduced surface roughness leads to reduction in surface roughness scattering and charge impurity scattering, therefore an enhanced intrinsic charge carrier mobility (3 folds) for graphene on h-BN/Si₃N₄/Si is found.

The invention relates to the field of detection, in particular to a nano-particle enhancement detection device based on non-modified monolayer graphene being used as a working electrode and the application thereof, provides the application of the non-modified monolayer graphene in the field of nano-particle enhancement detection, and further provides the nano-particle enhancement detection device, a nano-particle enhancement detection method and a relevant kit. According to the nano-particle enhancement detection method, the non-modified graphene is used as the working electrode, and therefore the electronic transmission rate is improved; modified nanogold and magnetic beads are used for amplifying current signals, and detection sensitivity is improved.

The invention provides a green and environmentally-friendly preparation method of graphene with low defect and large size. The preparation method comprises the steps of: synthesizing a pyrene-terminated copolymer by a RAFT (Reversible Addition Fragmentation Chain Transfer) polymerization method, and directly stripping monolayer graphene from the graphite surface through pi-pi superposition on the basis of not destroying the conjugation structure of graphene. According to the method, strong acid, strong base and cancerogenic substance hydrazine are not used, graphene is directly stripped from graphite, graphene with large size, low defect and excellent conductibility is prepared and the graphene preparation method is green and environmentally friendly; and as compared with the vapor deposition method and micro-mechanical stripping method, the method has the advantages of low cost, mass production and the like.

A method of preparing the electronic material called silicon intercalated epitaxial monolayer graphene comprises the steps of growing large scale high-quality graphene on metal surface, depositing silicon on the prepared epitaxial graphene and annealing to high temperature to intercalate the silicon to the interface of graphene and metal surface. Depending on the quantity of the silicon deposited on the graphene surface, the numbers of the silicon layers on the interface can be controlled and adjusted.

Periodic nanostructures for high energy-density and high-power density device and systems and uses thereof. Hierarchical nanostructured materials having stacked polymer nanowires forests interconnected by monolayer graphene sheets were fabricated through bottom-up nanofabrication. Driven by external voltage, aniline molecules and graphene oxide were alternatively assembled for hierarchical porous stacked nanostructures while graphene oxide was in-situ reduced to graphene during the assembly process. As-produced hierarchical nanostructures can be used as supercapacitor electrodes, which can utilize the discovered stack-dependent device properties.

The invention discloses a transfer method of CVD method prepared grapheme, characterized in that in a process of the existing transfer method, a target substrate is treated first, i.e. a layer of polymer solution is applied on the surface of the target substrate, and the solvent in the polymer is eliminated by drying. The polymer provided by the invention not only has strong adhesiveness on graphene, but also groups favorable for graphene doping are contained. Therefore, adhesive force between the target substrate and the graphene can achieve the 4B level, square resistance rise of monolayer graphene after transfer is almost zero, certain reduction effect is played, and the standard deviation rate of square resistance of a full piece (for example, 360mm*290mm) of graphene can not exceed 5%.

The invention relates to a preparation method of a composite material and the composite material. The preparation method comprises the following steps in parts by weight: a, adding 0.3-0.5 part of monolayer graphene oxide into 79 parts of anhydrous ethanol and ultrasonically stripping after magnetic stirring; b, adding 100 parts of UHMWPE (ultrahigh molecular weight polyethylene) into a solution and ultrasonically stripping after magnetic stirring; c, drying; d, grinding and smashing the dried substance; e, pre-pressing for 10-20 minutes at the pressure of 5-10MPa by using a press vulcanizer; f, electrically heating and airing; and g, sulfidizing and cooling. The composite material prepared by the method comprises 0.3-0.5 part by weight of monolayer graphene oxide and 100 parts by weight of UHMWPE. According to the preparation method of the composite material and the composite material, the mechanical property of UHMWPE is improved and the hardness, the tensile property and the friction and wear properties of the composite material are improved.

The present invention provides graphene nuclei including monolayer single-crystalline graphene nuclei and a method of growing from them two-dimensional graphene dendrites, with aspect ratio of the main branches increasing with growth time, on catalytic metal surface using thermal chemical vapor deposition. By controlling the supply rates of the carbon etching gas and the carbon deposition species, it results in graphene branches being merged to form a two-dimensional monolayer single-crystalline graphene plate and further allows multiple graphene plates to merge and form a large-area continuous monolayer graphene plate.

The invention discloses a micro ultra-wideband photodetector based on graphene. The micro ultra-wideband photodetector comprises a monocrystalline silicon substrate; a stress layer formed on the monocrystalline silicon substrate; and a heterojunction formed on the stress layer, wherein the heterojunction comprises a gate electrode, a first graphene layer, a dielectric layer, a second graphene layer, a source electrode which is parallel to and equidistant from the gate electrode, and a drain electrode layer structure, which are orderly arranged; the stress layer makes the heterojunction to be self-assembled into a microtube three-dimensional structure; and a current measurement loop is formed on the above structure. The invention further discloses a production method of the micro ultra-wideband photodetector based on the graphene. The three-dimensional microtube structure can greatly reduce the occupied area of chips, improve the light absorption rate and light utilization efficiency of the monolayer graphene, and greatly improve the responsivity of graphene photodetectors.

The invention discloses a preparation method of electronegative monolayer graphene. In the preparation method, graphite is taken as a raw material, water is taken as a dispersant, exfoliation of graphite is realized under assist of graphene quantum dot via mechanical exfoliation so as to obtain the electronegative monolayer graphene, wherein the carbon/hydrogen ratio of the graphene quantum dot ranges from 1.2:1 to 1.8:1. The electronegative monolayer graphene prepared via the above preparation method possesses a single layer structure and excellent electrical conductivity, and excellent water dispersibility at a pH value ranging from 2 to 12, and is negatively charged; the preparation method is simple, and is convenient to popularize; and cost is low.

The invention relates to a preparation method of a glassy carbon electrode for detecting pyrocatechol and/or paradioxybenzene in water. The method comprises the following steps: (1) adding deionized water into nitrogen doped graphene oxide until the concentration of the nitrogen doped graphene oxide in the deionized water is 2mg/mL, and carrying out ultrasonic dispersion for 2 hours to obtain dispersion liquid, wherein the nitrogen doped graphene oxide is synthesized from ammonium carbonate and monolayer graphene oxide as a precursor according to a weight ratio of (100 to 1) to (120 to 1) by virtue of a hydrothermal method; (2) polishing a bare glass carbon electrode with an effective diameter being 3mm to form a mirror surface, then sequentially carrying out ultrasonic treatment in absolute ethyl alcohol and deionized water for 5 minutes and drying; and (3) dropwise adding 10 microliter of dispersion liquid prepared by the step (1) on the surface of the bare glass carbon electrode treated by the step (2), and then drying to obtain the glassy carbon electrode. The glassy carbon electrode prepared by the method can be used for detecting pyrocatechol and/or paradioxybenzene in water, and is high in sensitivity, high in stability and high in repeatability.