KR102065048B1 - Analysis method of physical properties of graphene - Google Patents

Abstract

The present invention relates to a method for analyzing the physical properties (thickness, width, diameter, wrinkle, flatness) related to the graphene shape by using a scanning electron microscope (FE-SEM) equipment.
The present invention provides a method for manufacturing a metal substrate including: (a) providing a metal substrate having a plurality of grooves having a flat bottom; (b) uniformly dispersing a graphene sample on the metal substrate; And (c) observing the metal substrate with a scanning electron microscope (FE-SEM). It provides a method for observing the physical shape of the graphene containing ".

Description

{Analysis method of physical properties of graphene}

The present invention relates to a method for analyzing physical properties (thickness, width, diameter, wrinkle, flatness) related to the graphene shape by using a scanning electron microscope (FE-SEM) equipment.

Graphene includes synthetic graphene (Reduced Graphene Oxide), which is made by chemically exfoliating graphite, and graphene or graphene nanoplates made by physically breaking graphite, which is called the graphene family. Collectively.

Most of the research and development on graphene has been conducted in relation to industrial applications in terms of electrical properties, optical properties, and electromagnetic properties of the graphene electronic structure. However, the properties of graphene also show many differences depending on the morphological characteristics such as thickness, width, diameter, degree of wrinkles, and flatness.

Graphene is nanometer-sized, so you can see the electron microscope. The electron microscope is classified into a transmission electron microscope (FE-TEM) and a scanning electron microscope (FE-SEM). FE-TEM obtains information (morphology, atomic arrangement, crystal structure) about the material to be observed in the microscopic area of several tens of nanometers or less. The measurement condition is that the electron beam passes through the specimen and reaches the screen detector. Therefore, the specimen should be very thin and small. FE-SEM, on the other hand, requires that the irradiated electron beam stick out from the surface of the specimen. Therefore, the thickness and size of the specimen are irrelevant. In this case, the conductive treatment of the specimen is very important so that most of the irradiated electron beams can fit the specimen and flow through the current to the ground.

FE-SEM is a very important analytical tool for material research because it allows macroscopic observation and some degree of microscopic observation of specimens. The shape and average particle size of the existing 0-dimensional powder material, thickness and length information of the 1-dimensional linear material have been mainly obtained through the FE-SEM equipment. This is because the microscopic world is most easily understood by seeing directly.

However, graphene, a two-dimensional material, has plane diameters of several to several tens of micrometers, but its thickness is very thin compared to the plane diameter (1 nm or less from the atomic layer of graphene oxide). Due to these morphological characteristics, graphenes are stacked and crumpled, and it is not easy to separate and observe each graphene. In addition, the information on the degree of wrinkles, flatness, etc. of the graphene has not been known in the past.

If the physical information of graphene can be known in detail, it can provide key information on graphene adsorption properties, coating properties, and dispersing properties, which can be helpful for graphene specification and industrialization.

1. Patent Publication 10-2013-0142794 "graphene and graphene boundary analysis device and analysis method" 2. Patent 10-1663467 "graphene grain observation method and graphene grain observation device" 3. Patent 10-1494359 "Graphene reference derivation method and nano thin film analysis method using the same" 4. Patent 10-1538037 "X-ray analysis apparatus and X-ray analysis method for graphene having an extremely fine thickness" 5. Patent 10-1790506 "Method and Apparatus for Analyzing Graphene Family Organic Elements Using Plasma"

An object of the present invention is to provide a method for observing various physical and morphological characteristics of graphene, which have been difficult to analyze in the past, using a special substrate and a scanning electron microscope (FE-SEM).

The present invention provides a method for manufacturing a metal substrate including: (a) providing a metal substrate having a plurality of grooves having a flat bottom; (b) uniformly dispersing a graphene sample on the metal substrate; And (c) observing the metal substrate with a scanning electron microscope (FE-SEM). It provides a method for observing the physical shape of the graphene containing ".

As the metal substrate, a metal mesh laminated on the base plate, a TEM grid stacked on the base plate, or the like may be used.

In the step (b), the graphene dispersion solution may be dropped onto the metal substrate and then dried.

In the step (c), the graphene is attached to the upper surface of the metal substrate or the bottom of the groove, the part is attached to the upper surface of the metal substrate or the bottom of the groove and the remaining portion of the graphene and the metal substrate groove wall surface located in the empty space of the groove You can observe the graphene attached to it.

In addition, the present invention (d) step of determining whether the graphene adherence, flexibility, adhesion after bending, elasticity and permanent deformation (wrinkle state due to chemical bonding) based on the observation result in step (c) It can be done further.

According to the present invention has the following effects.

1. In the related art, although specific observation and analysis of physical properties according to the shape of graphene have not been made, according to the present invention, the degree of wrinkles, flatness, and adhesion in a bent state may be individually observed. .

2. At a glance, you can get information about the thickness and diameter of graphene.

3. Observe the physical shape to determine whether the graphene is wrinkled form, whether the graphene is wrinkled, or whether the graphene is thin and can be adsorbed on the base material.

4. It is possible to obtain information on the three-dimensional deformation of graphene by observing graphene bent in part and bent part in metal substrate.

1 is a schematic view of the metal substrate embodiments applied to the present invention.
FIG. 2 is a schematic diagram of a cross section of the metal substrate of FIG. 1. FIG.
FIG. 3 is a schematic view showing various cases of graphene positions when dispersing graphene on the grooved metal substrate.
4 is an enlarged image of the whole of the system grid and the through hole (the groove in the present invention) of the system grid.
FIG. 5 is a FE-SEM photograph showing a state in which graphene is aggregated on a conventional flat substrate (A, B) and graphene is separated and dispersed as much as possible by a grooved metal substrate (C). .
6 is a pleated graphene is attached to the metal substrate groove wall surface, the cross-sectional shape (A), the pleated portion (B1) located obliquely with respect to the plane and the FE photographed the pleated portion (B2) located on the plane -SEM picture.
FIG. 7 is an FE-SEM photograph of a portion C attached to the upper surface of the metal substrate and the remaining portion D attached to the groove wall surface, with each RGO placed at the edge of the metal groove inlet.
FIG. 8 is a FE-SEM photograph of GNP placed on the groove wall of a metal substrate.

The present invention provides a method for manufacturing a metal substrate including: (a) providing a metal substrate having a plurality of grooves having a flat bottom; (b) uniformly dispersing a graphene sample on the metal substrate; And (c) observing the metal substrate with a scanning electron microscope (FE-SEM). It provides a method for observing the physical shape of the graphene comprising a. ''

Hereinafter, with reference to the accompanying drawings and embodiments will be described in detail for each step the present invention.

1.step (a)

This step is to prepare a metal substrate having a plurality of grooves having a flat bottom.

Prepare a metal substrate that can flow the electron beam of the Scanning Electron Microscope (FE-SEM) to reduce the damage of graphene to a minimum, but can separate individual graphene particles and easily know the information about the diameter. In order to observe the three-dimensional deflection of graphene, a metal substrate having a plurality of grooves having a flat bottom is prepared.

1 shows embodiments of a metal substrate to which the present invention is applied. FIG. 2 illustrates a cross section of the metal substrate embodiments of FIG. 1.

FIG. 1A illustrates an integrated metal substrate 10a in which a plurality of grooves 12 recessed in the upper surface 11 are formed. The bottom surface 13 and the wall surface 14 of the groove can also be checked.

FIG. 1B illustrates a laminated metal substrate 10b in which a plate-like member having a plurality of through holes, such as a metal mesh and a TEM grid, is formed on the base plate 15. . In the present invention, the through hole is the groove 12, and the upper surface of the base plate 15 is the bottom surface 13 of the groove 12. Similarly, the thickness portion of the through hole immediately becomes the wall surface 14 of the groove 12.

The base plate and the metal mesh, the base plate and the system grid is laminated in a state of lamination with a tape (carbon double-sided tape, etc.), a binder (silver paste, carbon paste, bonds, etc.) or physical fastening method using a fastening member (Bolt fastening, fitting coupling, etc.) can be combined or attached by way of self-support. Of course, even in a non-bonded state, the base plate and the plate-shaped member formed with a plurality of through holes can be applied to the metal substrate of the present invention in a set.

 The metal substrates 10a and 10b of the present invention are not limited to metal type, thickness, groove shape, etc., but in order to intuitively grasp the size of the graphene through the present invention, the groove size information of the metal substrate should be known in advance.

 4 is an enlarged image of the whole of the system grid and the through hole (the groove in the present invention) of the system grid. The system grid is essentially a holder used essentially for a transmission electron microscope (FE-TEM), but can be used as a substrate member used for scanning electron microscope (FE-SEM) observation in the present invention.

As described above, when graphene is dispersed in the grooved metal substrate, the positional state of graphene may be roughly classified into the following three types.

(1) When attached to the upper surface of the metal substrate or the bottom surface of the groove

(2) When part is attached to the upper surface of the metal substrate or the bottom of the groove and the remaining part is located in the empty space of the groove

(3) When attached to the wall of metal substrate groove

Figure 3 is a schematic diagram showing the state of the above three graphene when the graphene is dispersed on the grooved metal substrate.

In a general flat plate, the graphene is entangled like agglomerates, and the viewing angle is limited because the graphene is stacked horizontally on the flat plate. However, by using the grooved metal substrate as described above, it is possible to separate and disperse the graphene. Since the dispersed graphene is placed in various positions as described above, the angles such as the attached state, the bending state, and the cross-sectional state of the metal substrate are various. Can be observed at

The metal substrate of the present invention is provided with a large specific surface area by the groove to separate the individual graphene as much as possible, the step is formed by the height is different by the groove, the state in which the graphene is laid 180 degrees from 0 ° to the horizontal plane By varying to °, the graphene observation angle of the two-dimensional shape is enriched.

As shown in (B) of FIG. 4, a method of changing the state of graphene placed in the groove may be added by coating a polymer on a metal mesh or forming a porous membrane to provide a step.

2. Step (b)

This step is to uniformly disperse the graphene sample on the metal substrate. This step may be proceeded to drop the graphene dispersion solution on the upper metal substrate and to dry.

Graphene (GP), graphene oxide (GO), graphene produced through reduction (RGO), graphene nanoplates (GNP), such as any of the family of graphene that is applied to the present invention 'graphene sample' Can be applied as

Graphene dispersion solution can be observed after dropping and drying on the metal substrate as it is without any special treatment. Powdered graphene is preferably prepared in a dilute concentration of the graphene dispersion solution, it is preferable to apply a small amount of dispersant to disperse through light sonication in order to prevent damage to the graphene specimens and improve dispersibility.

3. Step (c)

In this step, the metal substrate is observed by a scanning electron microscope (FE-SEM).

 In this step, the graphene of the three positions as described above, that is, the graphene attached to the smooth surface of the upper surface of the metal substrate or the bottom of the groove, the part is attached to the smooth surface of the upper surface of the metal substrate or the bottom of the groove, and the rest of the grooves The graphene located in the empty space and the graphene attached to the metal substrate groove wall can be observed.

4. Step (d)

This step is to determine whether the graphene adherence, flexibility, adhesion after bending, elasticity and permanent deformation (wrinkle state due to chemical bonding) based on the observation result in step (c).

Accordingly, it is possible to observe the detailed shape of the graphene, such as bending state (bending, bending, wrinkles, etc.), cross-sectional state of the graphene, as well as whether the graphene sample to be observed has the property of attaching to the base material, The physical behavior such as whether it can be attached to the base metal in a curved state can also be predicted.

FIG. 5 is a FE-SEM photograph showing a graph (a, b) in which graphene is aggregated on a conventional flat substrate and a graph (a) in which graphene is separated and dispersed as much as possible by a grooved metal substrate (C). .

FIG. 5A is a FE-SEM photograph of the state of the RGO powder on a planar substrate, where wrinkled and wrinkled shapes are observed, but the boundaries of individual powders cannot be identified, and in particular, observed in the present invention. There is no morphological information available about the graphene cross section, adsorption sites, and wrinkles.

FIG. 5B is a FE-SEM photograph taken in the state of GNP powder placed on a planar substrate, where the wrinkles are not well formed and how individual particles can be distinguished from each other. It is not possible to know in detail whether the shape of each particle and the shape of each particle.

(C) of Figure 5 is a FE-SEM photograph taken by applying the RGO powder as a sample by applying the present invention. The individual graphene particles are separated well so that the diameter information can be easily identified. In particular, the graphene particles can be attached to the substrate and can be attached vertically by bending.

6 is a pleated GO is attached to the metal substrate groove wall surface, the cross-sectional shape (A), the pleated portion (B1) located obliquely with respect to the plane and the pleated portion (B2) taken on the plane FE- SEM picture. The wrinkles can be observed at an angle so that the three-dimensional shape of the wrinkles can be easily measured and compared with the wrinkles on the plane.

FIG. 7 is a FE-SEM photograph of the RGO placed at the edge of the metal groove inlet and photographing the portion C attached to the upper surface of the metal substrate and the remaining portion D attached to the groove wall surface. From this picture, the observed RGO is observed to be attached to the upper surface of the metal substrate and the groove wall, and thus the graphene can be attached and bent, and deriving the property information that it can be attached even if the base metal is bent. I can do it. It is also confirmed that there are no wrinkles as found in GO observed in [FIG. 6].

FIG. 8 is a FE-SEM photograph of GNP placed on the groove wall of a metal substrate. Observation GNP can be seen that it has a flat nature without adsorption and bending as RGO shown in FIG. It can also be predicted that there is some elasticity through bending.

As described above, the present invention observes various morphological characteristics of graphene, which could not be understood in the conventional FE-SEM observation, and thus the adhesion of the graphene, flexibility, adhesion after bending, elasticity and permanent deformation (wrinkle state due to chemical bonding) ) Can be identified or predicted.

In the above, the present invention has been described in detail with specific examples. However, the present invention is not limited to the above embodiments and may be modified and modified without departing from the gist of the present invention. Therefore, the claims of the present invention include such modifications and variations.

10a, 10b: metal substrate 11: top 12: groove
13: groove bottom surface 14: groove wall surface

Claims (6)

(a) providing a metal substrate having a plurality of grooves having a flat bottom;
(b) uniformly dispersing a graphene sample on the metal substrate; And
(c) graphene attached to the upper surface of the metal substrate or the bottom surface of the groove by a scanning electron microscope (FE-SEM), a part of which is attached to the upper surface of the metal substrate or the bottom surface of the groove, and the remaining portion of the groove of the groove Discriminating and observing graphene positioned in a space and graphene attached to the metal substrate groove wall; Observing the physical shape of the graphene comprising a.
In claim 1,
The metal substrate is a physical shape observation method of the graphene, characterized in that the metal mesh laminated on the base plate.
In claim 1,
The metal substrate is a physical shape observation method of graphene, characterized in that the lamination (TEM Grid) on the base plate.
In claim 1,
In the step (b), the graphene dispersion solution is dropped on the upper surface of the metal substrate and dried, characterized in that the physical shape of the graphene.
delete The method according to any one of claims 1 to 4,
(d) based on the observation results in step (c) of the graphene, characterized in that the determination of the adhesion of the graphene, flexibility, adhesion after bending, elasticity and permanent deformation (wrinkle state due to chemical bonding) Physical shape observation method.

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