KR20100090580A - Method of maufacturing graphene material - Google Patents

Abstract

The present invention relates to a method for preparing a graphene material having high crystallinity and metal-semiconductor transition and capable of forming a template-dependent appearance of a multilayer graphene and a multilayer graphene-X composite material. The present invention comprises the steps of preparing a cooled solidified hydrocarbon from the liquid phase; Obtaining a single-phase carbene precursor through a low temperature pyrolysis reaction on the cooled solidified hydrocarbon; And etching the single phase carbene precursor with an aqueous solution.

Description

Method of manufacturing graphene material {Method of maufacturing graphene material}

The present invention relates to a method for preparing a graphene material, and more particularly, to a method for preparing a high crystalline and metal-semiconductor transitional graphene material.

Currently, there is an increasing demand for cost and process reduction in the display industry. One of the solutions to this situation is the introduction of nanotechnology. In fact, nanotechnology has already been studied in the semiconductor and display industries. For example, there is a nanoimprinting technology that can replace the lithography process, which takes a large part of the TET-LCD manufacturing process and the semiconductor process, and nanotechnology is also applied to the nano ink used for the PDP electrode. The most attention is the carbon nanotubes (CNT), which are called 'dream materials' and 'jewels of 21st century nanotechnology'.

On the other hand, important advances have been made in the theoretical, physical and chemical formation methods for making carbon-based nanostructures with homogeneous topologies. In particular, morphological control or surface modification from carbon precursors to graphene multilayer materials in colloidal form has been a major topic in many studies because of their biochemical usefulness due to low toxicity and good biocompatibility.

The graphene refers to a two-dimensional thin film of a honeycomb structure made of a layer of carbon atoms. The carbon atoms form a carbon hexagonal network surface having a two-dimensional structure upon chemical bonding by sp ² hybrid orbits. The aggregate of carbon atoms having this planar structure is graphene, which is 0.3 nm thick with only one carbon atom. Graphene has become one of the hottest subjects in physics since 2005, when the AKGeim research group at the University of Manchester, UK, introduced how to make thin, one-atom carbon films from graphite.

The reason is that graphene has not been able to carry out research in the field of particle physics as well as the unique quantum hole effect of graphene based on the fact that it does not have an effective mass of electrons and thus behaves as a relative particle moving at 1,000 kilometers per second. This is because particle physics experiments can be implemented indirectly through graphene.

Conventional silicon-based semiconductor processing technology is unable to manufacture a semiconductor device having a high density of less than 30nm class. This is because, when the thickness of the atomic layer of metal such as gold or aluminum deposited on the substrate is 30 nm or less, it is thermodynamically unstable and metal atoms are entangled with each other to obtain a uniform thin film. This is because they become nonuniform at nanoscale.

However, graphene has the potential to overcome the integration limitations of this silicon-based semiconductor device technology. Graphene has a characteristic of changing electrical resistance due to the change of the charge density according to the gate voltage because the thickness of the graphene is very thin, which is not more than a few nm corresponding to the thickness of the electron shield. The metal transistor can be implemented using this, and since the mobility of the charge transport body is large, it is expected to be applied to various fields because it can implement a high-speed electronic device.

The conventional method for obtaining graphene is classified into the following three kinds. First is a micro cleavage method using cellophane tape. The method can reduce the thickness of the graphite by allowing the graphite to be continuously separated using a cellophane tape, and the thin graphite film thus obtained is transferred onto the substrate, or thin graphite by rubbing the graphite onto the substrate as if chalked on a blackboard. It is a method of obtaining a thin film.

However, the method depends on the quality of the adhesive tape of Highly Oriented Pyrolytic Graphite (HOPG), and it is difficult to pattern electrodes by electron beam lithography due to the large amount of useless thick graphite particles. There is.

The second method is the epitaxial growth technique through thermal decomposition of SiC under high vacuum. This method is a technique that sublimates Si on the surface of SiC at high vacuum and high temperature, such as Moleclar Beam Epitaxy (MBE), so that the carbon atoms remaining on the surface form graphene.

However, in the second method, SiC itself should be used as a substrate, which has a serious problem that performance is not as good as that of SiO ₂ as an electronic material.

The third method is a method of utilizing the chemical peeling action of the graphite compound. However, the third method has not only succeeded in obtaining graphene, but only a few hundred nm thick pieces of graphite, and also has a problem that the chemicals intercalated between the graphite layers are not completely removed. .

Accordingly, the present inventors have developed a method for producing graphene which can be manufactured at low temperature without thermal and physical post-treatment.

An object of the present invention is to provide a method for producing a graphene material having control properties of the template (template) form in addition to the physicochemical properties of nanotubes and nanotubes and fullerenes.

Another object of the present invention is to provide a graphene material manufacturing method capable of forming a highly crystalline and metal-semiconductor transitional graphene material without a separate physicochemical treatment.

The present invention comprises the steps of preparing a cooled solidified hydrocarbon from the liquid phase; Obtaining a single-phase carbene precursor through a low temperature pyrolysis reaction on the cooled solidified hydrocarbon; And etching the single-phase carbene precursor with an aqueous solution.

Here, the hydrocarbon is characterized in that any one of acetone, propanol, isopropyl alcohol.

The low temperature pyrolysis reaction is characterized in that proceeds at 500 to 600 ℃.

Obtaining the single phase carbene precursor is characterized by performing vapor pressure vapor deposition on the single phase carbene precursor.

The vapor pressure vapor deposition is characterized in that it is carried out at a vacuum degree of less than 10 ^-2 torr.

The vapor pressure vapor deposition is characterized by using an inert carrier gas.

The carrier gas is characterized in that the argon (Ar) or helium (He).

The carrier gas is characterized by having a flow rate of 1 to 50 cm 3 / min.

The aqueous solution is characterized in that the acidic aqueous solution.

In addition, the present invention comprises the steps of preparing a cooled solidified hydrocarbon from the mixed liquid phase; Obtaining a composite-phase carbene-X precursor through low temperature pyrolysis of the cooled solidified hydrocarbon; And etching the composite carbene-X precursor with an aqueous solution.

Here, the hydrocarbon is characterized in that any one of acetone, propanol, isopropyl alcohol.

In the composite carbene-X precursor, X is any one of boron, nitrogen, sulfur, silicon.

The low temperature pyrolysis reaction is characterized in that proceeds at 500 to 600 ℃.

Obtaining the composite phase carbene-X precursor is characterized by performing vapor pressure vapor deposition on the composite phase carbene-X precursor on a mold.

The vapor pressure vapor deposition is characterized in that it is carried out at a vacuum degree of less than 10 ^-2 torr.

The vapor pressure vapor deposition is characterized by using an inert carrier gas.

The carrier gas is characterized in that the argon (Ar) or helium (He).

The carrier gas is characterized by having a flow rate of 1 to 50 cm 3 / min.

The aqueous solution is characterized in that the acidic aqueous solution.

The present invention can produce a graphene material having excellent carbon crystallinity and a graphene material having a multilayer graphene composite at a low temperature of 500 to 650 ° C. without thermal and physical post-treatment. It can be interlocked with fuel cells, so it is possible to manufacture environmentally friendly objects.

In addition, the present invention provides a graphene material that can determine the size and shape of the multilayer graphene and the multilayer graphene composite according to the size and shape of the mold, so that the hydrophobicity of the outermost surface of the carbon film is easily obtained by physicochemical oxidation. It can be called hydrophilic.

In addition, the present invention can be used for specific applications requiring optical and electromagnetic applications by producing graphene materials expressing optical luminescence or electromagnetic properties by impurity introduction treatment such as deposition or supporting of metal ions.

Hereinafter, a method for preparing a graphene material according to embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the following embodiments, and has ordinary skill in the art. If grown, the graphene material manufacturing method according to the present invention can be implemented in various other methods without departing from the technical spirit of the present invention.

The present invention relates to a low temperature vacuum pyrolysis of molecular carbon precursors obtained from the controlled evaporation of a single / mixture of solidified cooling solids from a liquid phase, and to self-assembly of a carbon composite produced in conjunction. By implementing sufficient crystallinity of the pen and graphene composites, graphene materials that form highly crystalline and metal-semiconductor transitionable multilayer graphene materials or multilayer graphene composite materials having control properties of template dependent external morphology (Graphene Materials) : GM) can be manufactured.

In the graphene material manufacturing method according to an embodiment of the present invention, a multi-layer obtained by producing a carbene precursor by low-temperature thermal decomposition of the cooling solidified hydrocarbon from the liquid phase consisting of acetone, and depositing the carbene precursor in a vapor pressure gas phase on a mold Graphene is a method of etching an aqueous solution.

According to another aspect of the present invention, there is provided a method for preparing a graphene material, which generates a composite phase carbene-X precursor by low temperature thermal decomposition of a cooled solidified hydrocarbon from a mixed liquid phase containing acetone as a main material, and the carbene-X precursor. Is a method of etching a multilayer graphene-X composite obtained by vapor deposition on a mold by an aqueous solution. X in the carbene-X precursor is composed of any one of boron, nitrogen, sulfur, silicon.

According to the above method, the present invention can prepare a graphene material having a very good carbon crystallinity and a graphene material having a multilayer graphene composite at a low temperature of 500 ~ 650 ℃ without thermal and physical post-treatment.

In addition, the present invention can be used as a material for forming a carbon film hydrocarbon can be interlocked with the fuel cell and the like can produce an environmentally friendly object.

In addition, the present invention can produce a graphene material in which the size and shape of the multilayer graphene and the multilayer graphene composite are determined according to the size and shape of the mold.

In addition, the present invention, the hydrophobicity of the outermost surface of the carbon film can be easily converted to hydrophilic by physicochemical oxidation.

Specifically, the graphene material manufacturing method according to an embodiment of the present invention will be described.

First, a cooled solidified hydrocarbon is prepared from the liquid phase. The liquid phase is composed of any one of acetone, propanol, isopropyl alcohol, preferably, acetone. Thereafter, low temperature pyrolysis of the cooled solidified hydrocarbon is performed to produce a single phase carbene precursor. The carbene precursor is composed of a hydrocarbon, and the carbene precursor is preferably purchased and used by a manufacturer known or commercially available in the art.

Graphene material production method when the liquid phase is composed of acetone, put 100ml of acetone in a 200ml beaker, performing low-temperature pyrolysis in a vacuum, preferably, the temperature of the furnace to operate at 500 ~ 650 ℃ . As such, when the liquid phase is composed of a single material of acetone, carbene, which is a precursor of graphene formation, is formed at 590 ° C.

Thereafter, the degree of vacuum inside the reactor is maintained at 10 ⁻² torr or less without injecting a carrier gas from a mass flow controller (MFC), and vapor pressure vapor deposition is performed to suppress the oxide phase of the graphene material as much as possible. You get In the vapor pressure vapor deposition, a carrier gas uses argon (Ar), helium (He), etc. as an inert gas, and the inert gas is controlled to have a flow rate of 1 to 50 cm 3 / min, and as a binary gas. Nitrogen may be used representatively. Reactive gases may be used for special purposes, but with caution regarding the material selection of the reactor and accessories.

By controlling the flow rate and reaction time of the carrier gas, it is possible to control the thickness of the multilayered graphene material obtained and the size of the crystalline grains. Specifically, when operating at a low flow rate for a short time, a high graphene material of several nm thickness is obtained, and when operating at a high speed for a short time, an amorphous graphene material of several nm thickness is obtained. do. That is, the grain crystalline of the graphene material depends on the flow rate of the carrier gas, and the thickness of the crystalline depends linearly on the reactor operating time.

Next, the multilayer graphene is etched with an aqueous solution, thereby preparing a graphene material according to an embodiment of the present invention. The aqueous solution is an acidic aqueous solution, and serves to dissolve or wash the remaining porous silica or unreacted metal ions. Preferably, the graphene material is soaked for 3-10 hours at room temperature using an acidic aqueous solution of 5-9M, more preferably 7M. If agitated for effective treatment, the treatment effect can be increased. The pH for the treatment must maintain a strong acidity, the pH range is preferably 0 to 3. The acidic aqueous solution is advantageous to arsenic acid-based HF, HCl, or mixtures thereof, and when using oxygen acid-based sulfuric acid or nitric acid, graphene oxide can be increased to affect the electrical and optical properties. It is desirable to.

The graphene material prepared according to the present invention has a homogeneous graphene multilayer structure capable of controlling polarity (hydrophilicity / hydrophobicity), has a thickness of 1 to 50 nm, and has high crystallinity and metal-semiconductor transition.

Meanwhile, the graphene material manufacturing method according to another embodiment of the present invention will be described.

First, a cooled solidified hydrocarbon is produced from the mixed liquid phase. The mixed liquid phase uses any one of acetone, propanol and isopropyl alcohol as the main substance, preferably, uses acetone as the main substance and includes any one of ammonia, boric acid, carbon sulfide and silane chloride. . Thereafter, low temperature pyrolysis of the cooled solidified hydrocarbon is performed to produce a composite phase carbene-X precursor. The carbene precursor is composed of a hydrocarbon, and the carbene precursor is preferably purchased and used by a manufacturer known or commercially available in the art. In the composite carbene-X precursor, X is any one of ammonia, boric acid, carbon sulfide and silane chloride.

A method for producing a graphene material using acetone as the main material and containing any one of ammonia, boric acid, carbon sulfide and silane chloride may be performed by adjusting the proportion of the liquid mixture according to the properties required for the 200 ml beaker. 150 ml is added and low temperature pyrolysis is carried out in a vacuum, preferably the temperature of the furnace is operated at 500-650 ° C. For example, in order to obtain sulfide-treated graphene having improved conductivity, acetone: carbon sulfide = x: y is adjusted according to conductivity, and the smaller the ratio of x / y, the higher the conductivity. On the other hand, when the optical sensitivity is increased, the smaller the ratio value of acetone: ammonia number = x: y, the higher the optical quantum efficiency. In order to prevent the inhalation of water, it is necessary to install a trap for removing water or a desiccant before adding the reactor.

Thereafter, the degree of vacuum inside the reactor is maintained at 10 ⁻² torr or lower without injection of carrier gas from the MFC, and vapor pressure vapor deposition is performed while suppressing the oxide phase of the graphene material as much as possible to obtain a multilayer graphene-X composite. . In the vapor pressure vapor deposition, a carrier gas is used as an inert gas, Ar, He, etc., and the inert gas is controlled to have a flow rate of 1 to 50 cm 3 / min, and nitrogen may be used as a binary atom gas. Reactive gases may be used for special purposes, but with caution regarding the material selection of the reactor and accessories.

By controlling the flow rate and reaction time of the carrier gas, it is possible to control the thickness of the obtained multilayered graphene material and the size of the crystalline grains.

Thereafter, the multilayer graphene-X composite is etched with an aqueous solution, thereby preparing a graphene material according to another embodiment of the present invention. The aqueous solution is an acidic aqueous solution, and serves to dissolve or wash the remaining porous silica or unreacted metal ions. Preferably, the graphene material is soaked for 3-10 hours at room temperature using an acidic aqueous solution of 5-9M, more preferably 7M. If agitated for effective treatment, the treatment effect can be increased. The pH for the treatment must maintain a strong acidity, the pH range is preferably 0 to 3. The acidic aqueous solution is advantageous to the non-acidic HF, HCl or mixtures thereof, and when using oxygen acid sulfuric acid or nitric acid, the graphene oxide increases to affect the electrical and optical properties to use HF It is preferable.

1 is a schematic explanatory view of a method for obtaining product 1 and product 2 through a graphene material according to the present invention, and FIG. 2 is a schematic cross-sectional view of a reaction apparatus for producing another graphene material according to the present invention.

As shown in Figure 1 and 2, in the case of the product 1 using Cu or NaCl or polymide substrate (substrate, 100), through the vacuum pyrolysis of the low-temperature cooling solidified acetone through the reactor 10 The resultant composite (GM / substrate) 101 was pickled, washed with water, and ethyl acetate to obtain product 1, which is a flexible planar graphene structure (Flexible GM, 102) having a primary structure.

More specifically, after polishing a surface of a 1 cm x 1 cm Cu substrate using an Ar gun, it is horizontal to a quartz tube 210 of the reaction apparatus 10 shown in FIG. The substrate 200 is held at an inclination angle of 60 ° with respect to the substrate 200, and the vacuum is maintained at 10 ⁻² torr or less. Ar (291) was introduced at a flow rate of 10 cm 3 / min using an MFC connected to a quartz tube in a vacuum state, and after 10 minutes, the furnace was left at 590 ° C. at a rate of 20 degrees per minute. The solidified acetone 292 gas is introduced. The deposition thickness of the carbene layer thus formed is linearly proportional to the deposition time and is formed into a uniform thin film of 2 nm after 1 hour and 10 nm after 5 hours.

In order to prevent possible hygroscopicity, it is preferable to store in an inert 293 atmosphere of Ar and N ₂ , and it is recommended to separate the substrate by pickling immediately after cooling to room temperature. When the thin film has a thickness of 2 nm, it is pale yellow. At 10 nm thick, the color becomes thicker and black at 10 nm or more. In the case of pickling, a 20% graphene multilayer thin film / Cu complex was deposited by placing 20 ml of a 48% HF solution, which is a part of a known method, in a 50 ml polypropylene (PP) container, and after 12 hours, the graphene multilayer thin film was placed on top of the pickling solution. After recovering and washing with water twice, dried in the air, washed twice in ethanol and stored in hexane.

In the case of the product 2, nanoparticles, preferably, a composite obtained by vacuum pyrolysis of acetone having a mean diameter of 6 nm palladium (Pd) nanoparticles 110 by a known method and low temperature cooling solidified acetone through the reactor 10 (Pd / GM, 111) is pickled to obtain product 2 which is a graphene-based thin film permeable membrane (GM Membrane, 112).

More specifically, in the reversed phase method of forming a graphene multilayer on the palladium (Pd) nanoparticles 110, Pd (acac) ₂ (acac = acetylacetonate) (molecular weight: 304.64) 0.3 mmol = 0.0914 dried at 120 ° C. g, 0.0923 g (99%) was added, 100 cc of diphenylether 100 ml oleic acid and 0.15 cc of oleylamine were stirred at 120 ° C. for 1 hour to remove residual moisture. A cooler was installed and the temperature was increased to 220 ° C. at a rate of 10 ° per minute to adjust the growth of palladium nanoparticles to about 6 nm for 30 minutes.

Since the size adjustment of the palladium nanoparticles depends on the concentration and reaction time of two reaction factors according to nuclear growth, the average particle diameter is reduced to 3 nm when 0.1 mmol of Pd precursor is used under the same conditions. When the reaction precursor is used, the average diameter is increased to 10 nm. Since the reaction time promotes uneven growth of the nucleus, it is preferable to perform the reaction in 30 minutes or less. If the reaction time is reduced to 10 minutes under the same conditions, the average diameter becomes smaller to 2 nm. As such, the graphene thin film permeation was carried out in the same manner as in the production method of the product 1 while placing the palladium nanoparticles in an alumina container and tilting the quartz tube 210 of the reactor 10 shown in FIG. A film 112 is formed.

3 is an enlarged HRTEM image of product 1. FIG.

As can be seen in Figure 3, product 1 consists of a composite of particles having a spherical shape.

4 is a graph showing a graphene thin film permeable membrane of product 2. FIG.

As shown in FIG. 4, the left image is an image diagram of 6 nm Fe ₃ O ₄ nanoparticles, the upper right image is an enlarged image diagram of the particles measured in the (110) direction, and the lower right image is It shows good crystallinity.

As described above, the present invention provides a graphene material in which the size and shape of the multilayer graphene and the multilayer graphene composite are determined according to the size and shape of the mold, so that the hydrophobicity of the outermost surface of the carbon film is physicochemically treated. Can be easily converted to hydrophilic.

As mentioned above, although the present invention has been illustrated and described with reference to specific embodiments, the present invention is not limited thereto, and the following claims are not limited to the scope of the present invention without departing from the spirit and scope of the present invention. It can be easily understood by those skilled in the art that can be modified and modified.

1 is a schematic illustration of a method for obtaining product 1 and product 2 through a graphene material according to the present invention.

2 is a schematic cross-sectional view of a reaction apparatus for producing a graphene material according to the present invention.

3 is an enlarged HRTEM image of product 1. FIG.

4 is a graph showing a graphene thin film permeable membrane of product 2. FIG.

Explanation of symbols on the main parts of the drawings

10: reactor 100,200: substrate

101: composite (GM / substrate) 102: bendable planar graphene structure

110: 6 nm Pd nanoparticles with an average diameter 111: composite (Pd / GM)

112: graphene base thin film transmission membrane 210: quartz tube

291 argon 292 acetone

293: inactive

Claims (19)

Preparing a cooled solidified hydrocarbon from the liquid phase; Obtaining a single-phase carbene precursor through a low temperature pyrolysis reaction on the cooled solidified hydrocarbon; And Etching the single phase carbene precursor with an aqueous solution; Graphene material manufacturing method comprising a. The method of claim 1, The hydrocarbon is a graphene material manufacturing method, characterized in that any one of acetone, propanol, isopropyl alcohol. The method of claim 1, The low temperature pyrolysis reaction is a graphene material manufacturing method, characterized in that proceeds at 500 to 600 ℃. The method of claim 1, Obtaining the single phase carbene precursor, And subjecting the single-phase carbene precursor to vapor phase vapor deposition. The method of claim 4, wherein The vapor pressure vapor deposition is a method for producing a graphene material, characterized in that carried out at a vacuum degree of less than 10 ^-2 torr. The method of claim 4, wherein The vapor pressure vapor deposition is performed using an inert carrier gas. The method of claim 6, The carrier gas is an argon (Ar) or helium (He) characterized in that the graphene material manufacturing method. The method of claim 6, And the carrier gas has a flow rate of 1 to 50 cm 3 / min. The method of claim 1, The aqueous solution is a graphene material manufacturing method, characterized in that the acidic aqueous solution. Preparing a cooled solidified hydrocarbon from the mixed liquid phase; Obtaining a composite-phase carbene-X precursor through low temperature pyrolysis of the cooled solidified hydrocarbon; And Etching the composite carbene-X precursor with an aqueous solution; Graphene material manufacturing method comprising a. The method of claim 10, The hydrocarbon is a graphene material manufacturing method, characterized in that any one of acetone, propanol, isopropyl alcohol. The method of claim 10, In the composite carbene-X precursor, wherein X is any one of boron, nitrogen, sulfur, silicon. The method of claim 10, The low temperature pyrolysis reaction is a graphene material manufacturing method, characterized in that proceeds at 500 to 600 ℃. The method of claim 10, Obtaining the composite carbene-X precursor, A method for producing a graphene material, characterized in that the vapor phase vapor deposition of the composite phase carbene-X precursor on a mold. The method of claim 14, The vapor pressure vapor deposition is a method for producing a graphene material, characterized in that carried out at a vacuum degree of less than 10 ^-2 torr. The method of claim 14, The vapor pressure vapor deposition is performed using an inert carrier gas. The method of claim 16, The carrier gas is an argon (Ar) or helium (He) characterized in that the graphene material manufacturing method. The method of claim 16, And the carrier gas has a flow rate of 1 to 50 cm 3 / min. The method of claim 10, The aqueous solution is a graphene material manufacturing method, characterized in that the acidic aqueous solution.

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