TWI411572B - Transmission electron microscope grid and method for making same - Google Patents

Abstract

The invention relates to a transmission electron microscope grid. The transmission electron microscope grid includes a grid, and a graphene sheet-carbon nanotube film composite structure covered on the grid. A part of the composite structure are suspended. The composite structure includes at least a carbon nanotube film structure and a plurality of graphene sheets. The carbon nanotube film structure includes a plurality of micropores. At least one micropore of the carbon nanotube film structure is covered by one of the plurality of graphene sheets. The present invention also relates to a method for making the transmission electron microscope grid.

Description

Transmission electron micro-gate and preparation method thereof

The invention relates to a transmission electron microscope microgrid and a preparation method thereof.

In transmission electron microscopy, an amorphous carbon support film (microgrid) is an important tool for carrying powder samples for high-resolution image observation (HRTEM) observation by transmission electron microscopy. With the continuous development of nanomaterial research, microgrids are increasingly used in the field of electron microscopy characterization of nanomaterials. In the prior art, the microgrid applied to a transmission electron microscope is usually formed by covering a metal mesh such as a copper mesh or a nickel mesh with a porous organic film and then vapor-depositing an amorphous carbon film. However, in practical applications, especially when observing the high-resolution image of the TEM of the nanometer-sized particles, the amorphous carbon film in the micro-gate is thicker, the contrast noise is larger, and the transmission electron microscope imaging of the nano-particles is performed. The increase in resolution has a great impact.

In view of the above, a TEM micro-grid and a preparation method thereof are provided, wherein the TEM micro-gate is more effective for nano-scale particles, and it is more necessary to obtain a high-resolution image of a transmission electron microscope.

A TEM microgrid comprising a grid and a graphene sheet-nanocarbon tube membrane composite structure covering the grid, and the grid portion is suspended by the grid portion, the graphene sheet-nanocarbon tube membrane composite structure The method includes at least one carbon nanotube film structure and a plurality of graphene sheets, and the carbon nanotube film structure comprises a plurality of micropores, wherein at least one micropores are covered by a graphene sheet.

A TEM microgrid comprising a grid, and a graphene sheet-nanocarbon tube membrane composite structure covering the grid, and being suspended by the grid portion, the graphene sheet-nanocarbon tube membrane composite The structure comprises at least one carbon nanotube film structure and a plurality of graphene sheets, wherein the carbon nanotube membrane structure comprises a plurality of nano carbon pipeline crossovers and a plurality of micros formed by the plurality of intersecting nanocarbon pipelines a hole, wherein at least one of the micropores is covered by a graphene sheet.

A method for preparing a transmission electron microstrip microgate, comprising the steps of: providing a self-supporting carbon nanotube film structure, and a graphene sheet dispersion comprising a plurality of micropores; the graphite The olefin dispersion disperses the surface of the carbon nanotube film structure; drying the carbon nanotube film structure infiltrated by the graphene sheet, thereby compounding the graphene sheet with the carbon nanotube film structure to form a graphene sheet a carbon nanotube film composite structure; and covering the graphene sheet-carbon nanotube film composite structure with a grid.

Compared with the prior art, the TEM microgrid and the preparation method thereof are obtained by extracting a carbon nanotube film structure from a carbon nanotube array, and using the carbon nanotube film structure as a microporous structure. Supporting the skeleton, the dangling arrangement of the graphene sheets is achieved by covering the micropores of the support skeleton with graphene sheets. Since the graphene sheets have an extremely thin thickness, the contrast noise generated in the transmission electron microscope observation is small, so that a TEM photograph with a higher resolution can be obtained.

The TEM micro-gate and the preparation method thereof provided by the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

Referring to FIG. 1, a method for preparing a TEM micro-gate according to a first embodiment of the present invention mainly includes the following steps:

In the first step, a carbon nanotube film structure and a graphene sheet dispersion are provided.

The carbon nanotube membrane structure comprises a plurality of layers of cross-laminated carbon nanotube membranes. The carbon nanotube film is obtained by directly pulling from a carbon nanotube array, and the preparation method thereof comprises the following steps:

First, an array of carbon nanotubes is provided on a growth substrate that is a super-aligned array of carbon nanotubes.

The carbon nanotube array is prepared by chemical vapor deposition, and the carbon nanotube array is a plurality of pure carbon nanotube arrays formed by carbon nanotubes which are parallel to each other and perpendicular to the growth substrate. Through the above controlled growth conditions, the aligned carbon nanotube array contains substantially no impurities, such as amorphous carbon or residual catalyst metal particles, and is suitable for drawing a carbon nanotube film therefrom. The carbon nanotube array provided by the embodiment of the invention is one of a single-walled carbon nanotube array, a double-walled carbon nanotube array, and a multi-walled carbon nanotube array. The carbon nanotubes have a diameter of 0.5 to 50 nm and a length of 50 nm to 5 mm. In this embodiment, the length of the carbon nanotubes is preferably from 100 micrometers to 900 micrometers.

Next, a carbon nanotube film is obtained by pulling a carbon nanotube from the carbon nanotube array using a stretching tool, which specifically includes the following steps: (a) from the super-shoring carbon nanotube array One of the plurality of carbon nanotubes having a certain width or a certain width is selected. In this embodiment, it is preferable to contact the carbon nanotube array with a tape, a tweezers or a clip having a certain width to select one or a plurality of carbon nanotubes having a certain width. (b) stretching the selected carbon nanotubes at a certain speed to form a plurality of carbon nanotube segments connected end to end, thereby forming a continuous carbon nanotube film. The pull direction is substantially perpendicular to the growth direction of the nanotube array.

In the above stretching process, the plurality of carbon nanotube segments are gradually separated from the growth substrate in the stretching direction under the tensile force, and the selected plurality of carbon nanotube segments are respectively combined with the other due to the van der Waals force. The carbon nanotube segments are continuously drawn end to end to form a continuous, uniform, self-supporting carbon nanotube film having a width. The so-called "self-supporting structure" means that the carbon nanotube film can maintain the shape of a film without being supported by a support. Referring to FIG. 2, the carbon nanotube film comprises a plurality of carbon nanotubes arranged in a preferred orientation in the same direction and connected end to end by a van der Waals force, the carbon nanotubes being arranged substantially in the stretching direction and parallel to the Nano carbon tube membrane surface. The method of directly stretching to obtain a carbon nanotube film is simple and rapid, and is suitable for industrial application.

The width of the carbon nanotube film is related to the size of the carbon nanotube array, and the length of the carbon nanotube film is not limited and can be obtained according to actual needs. When the area of the carbon nanotube array is 4 inches, the width of the carbon nanotube film is 3 mm to 10 cm, and the thickness of the carbon nanotube film is 0.5 nm to 100 μm.

It can be understood that the preparation method of the carbon nanotube film structure may further include: laminating and cross laying a plurality of the carbon nanotube films. Specifically, a carbon nanotube film may be first covered in one direction to one frame, and another carbon nanotube film may be covered in another direction to the surface of the previous carbon nanotube film, so that it is repeated several times. A plurality of carbon nanotube membranes are laid on the frame. The plurality of carbon nanotube films may be laid in different directions or may be laid only in two intersecting directions. It can be understood that the carbon nanotube membrane structure is also a self-supporting structure. The edge of the carbon nanotube membrane structure is fixed by the frame, and the middle portion is suspended.

Since the carbon nanotube film has a large specific surface area, the carbon nanotube film has a large viscosity, so the multilayer carbon nanotube film can be closely combined with each other to form a stable carbon nanotube through the van der Waals force. Membrane structure. In the carbon nanotube membrane structure, the number of layers of the carbon nanotube membrane is not limited, and the adjacent two layers of carbon nanotube membranes have an intersection angle α, 0° < α ≦ 90 °. This embodiment is preferably α=90°, that is, the plurality of carbon nanotube films are stacked on each other only in two mutually perpendicular directions, and the number of layers of the carbon nanotube film in the carbon nanotube film structure is 2 to 4 layers. .

After the above-described carbon nanotube film structure is formed, the carbon nanotube film structure may be further treated with an organic solvent to form a plurality of micropores in the carbon nanotube film structure.

The organic solvent is a volatile organic solvent at normal temperature, and one or a mixture of ethanol, methanol, acetone, dichloroethane and chloroform may be used. The organic solvent in this embodiment is ethanol. The organic solvent should have good wettability with the carbon nanotube. The step of treating with an organic solvent is specifically: infiltrating the entire surface of the carbon nanotube film structure formed on the frame by a test tube to infiltrate the entire carbon nanotube film structure, or the above-mentioned nano carbon can also be used. The tubular membrane structure is immersed in a container containing an organic solvent to infiltrate. Referring to FIG. 3 and FIG. 7 , after the carbon nanotube membrane structure is infiltrated by an organic solvent, the adjacent carbon nanotubes are gathered side by side and contracted into a nano carbon line with a spacing distribution, the nanometer. The carbon pipeline consists of a number of carbon nanotubes connected end to end by Van der Valli. There is a gap between the nanocarbon lines arranged substantially in the same direction. Since the carbon nanotubes in the adjacent two layers of carbon nanotube membranes have a crossing angle α and 0<α≦90°, the nanocarbon pipelines in the adjacent two layers of carbon nanotube membranes after the organic solvent treatment are mutually Crossing to form a plurality of micropores. After the organic solvent treatment, the viscosity of the carbon nanotube film is lowered. The size of the micropores of the carbon nanotube membrane structure is from 1 nm to 10 μm, preferably from 1 nm to 900 nm. In this embodiment, the intersection angle α=90°, so that the nanocarbon pipelines in the carbon nanotube membrane structure substantially cross each other perpendicularly to form a large number of micropores. Preferably, when the carbon nanotube structure comprises four stacked carbon nanotube membranes, the micropores having a size of nanometers in the nanocarbon membrane membrane structure can reach more than 60%. It can be understood that the larger the number of the laminated carbon nanotube film, the smaller the size of the micropores of the carbon nanotube film structure. Therefore, the desired pore size can be obtained by adjusting the number of the carbon nanotube membranes. The size of the micropores should be smaller than the size of the graphene sheet so that a graphene sheet can completely cover the micropores. It can be understood that the step is an optional step. When the solvent in the graphene sheet dispersion is a volatile organic solvent, the carbon nanotube membrane structure can be directly infiltrated through the dispersion through the subsequent step 2, and the step is achieved. The same effect.

The graphene sheet dispersion is obtained by dispersing a graphene sheet in a solvent. In this embodiment, the method for preparing the graphene sheet dispersion comprises: providing a certain amount of graphene sheets; placing the graphene sheets in a solvent to form a mixture; ultrasonically shaking the mixture to uniformly disperse the graphene sheets and It is suspended in the solvent to obtain a graphene sheet dispersion. In this example, the mixture was shaken in an ultrasonic shaker for about 15 minutes. It will be appreciated that other methods of dispersing the graphene sheet may be employed, such as stirring the mixture of the graphene sheet and the solvent by mechanical agitation.

The solvent should be selected as a low molecular weight solvent which is advantageous for the dispersion of graphene sheets and which is completely volatile, such as a mixture of one or more of water, ethanol, methanol, acetone, dichloroethane and chloroform. In this embodiment, the solvent is water. It can be understood that the solvent only functions to uniformly disperse the graphene sheet, so the solvent should not react with the graphene sheet, such as a chemical reaction or dissolution of the graphene sheet in a solvent.

The graphene sheet is composed of a single layer or a plurality of graphenes. Preferably, the number of layers of the graphene sheets in the graphene sheet dispersion is 1-3 layers, so that the transmission electron micro-gate has a better contrast. The graphene is a two-dimensional sheet-like structure formed by carbon atom fusion by sp2 bonding. The graphene sheet has a size of 10 microns or less and may be less than 1 micron. The graphene sheet has a concentration of 5% (volume percentage) or less in the sample dispersion to be tested.

In step two, the graphene sheet dispersion is impregnated onto the surface of the carbon nanotube membrane structure.

The graphene sheet dispersion can be dropwise added to the surface of the above-mentioned carbon nanotube film structure through a dropper so that the surface of the carbon nanotube film structure is wetted by the graphene sheet dispersion. It can be understood that when the structure of the carbon nanotube membrane is large, the whole carbon nanotube membrane structure can be immersed in the graphene sheet dispersion by other means, and the carbon nanotube membrane structure can be further Removed from the graphene sheet dispersion.

In the present embodiment, a carbon nanotube film structure infiltrated by the graphene sheet dispersion is formed on the frame by dropping a graphene sheet dispersion onto the surface of the carbon nanotube film structure laid on the frame.

After infiltrating the carbon nanotube film structure by the graphene sheet dispersion, another nano carbon tube film structure may be further covered on the surface of the above-mentioned carbon nanotube film structure infiltrated by the graphene sheet dispersion to form a sandwich structure. .

It will be appreciated that the other carbon nanotube membrane structure may comprise a single or multiple layer of carbon nanotube membranes, which may have the same or different structure as the original carbon nanotube membrane structure. This step may be repeated with the second step, that is, after the sandwich structure is formed, the graphene sheet dispersion droplet is further added to the surface of the sandwich structure, and further covers another carbon nanotube film structure, thereby forming a multilayer sandwich. structure. The multilayer sandwich structure comprises a multilayered carbon nanotube film structure laminated with a plurality of layers of graphene sheets dispersed in a liquid phase. In this embodiment, the sandwich structure is a three-layer sandwich structure formed by a two-layer carbon nanotube film structure and a layer of graphene sheet dispersion. The two-layer carbon nanotube film structure holds the graphene sheets in the middle graphene sheet dispersion, thereby making the graphene sheets more firmly fixed. This step is an optional step.

In the third step, the carbon nanotube film structure infiltrated by the graphene sheet is dried, so that the graphene sheet and the carbon nanotube film structure are combined to form a graphene sheet-nanocarbon tube film composite structure.

After the graphene sheet dispersion is dried, a graphene sheet layer is formed on the surface of the carbon nanotube film structure. The graphene sheets in the graphene sheet layer may be continuously or discretely distributed on the surface of the carbon nanotube film structure, depending on the number and concentration of the graphene sheet dispersion. Referring to FIG. 7, in the graphene sheet-nanocarbon tube film composite structure, at least one graphene sheet covers at least one micropores in the carbon nanotube film structure.

When a three-layer sandwich structure is formed, the carbon nanotubes in the two-layer carbon nanotube film structure sandwich the graphene sheets in the graphene sheet layer, thereby fixing the graphene sheets more stably in the three-layer sandwich layer. In the structure.

After forming the graphene sheet-nanocarbon tube film composite structure, the graphene sheet-nano carbon tube film composite structure may be further processed to make the graphene sheet and the carbon nanotube tube in the carbon nanotube film Bonded connection.

The processing step may specifically be irradiating the graphene sheet-carbon nanotube film composite structure by laser or ultraviolet light; or bombarding the graphene sheet-carbon nanotube film composite structure by high-energy particles. After the treatment, the carbon atoms in the graphene sheet and the carbon atoms in the carbon nanotubes are covalently bonded by sp3 hybridization, so that the graphene sheets are more stably fixed on the surface of the carbon nanotube membrane structure. This step is an optional step, and when the method does not include the step, the graphene sheet is bonded to the carbon nanotube by a van der Waals force.

In step four, the graphene sheet-nanocarbon tube film composite structure is covered with a metal grid.

The metal mesh has at least one through hole, and the graphene sheet-carbon nanotube film composite structure covers a portion of the through hole.

When the graphene sheet-nanocarbon tube film composite structure has a large area, the method further includes: spacing a plurality of metal grids; and covering the plurality of metals with the graphene sheet-nanocarbon tube film composite structure Grid; and disconnecting the graphene sheet-nanocarbon tube film composite structure from two adjacent metal grids, thereby forming a plurality of surfaces covered with a graphene sheet-nanocarbon tube film composite structure at one time Metal grid.

Specifically, a laser beam can be used to focus and illuminate between two adjacent metal meshes to blow the graphene sheet-carbon nanotube film composite structure. In this embodiment, the laser beam power is 5 to 30 watts (W), preferably 18 watts.

Further, the graphene sheet-nanocarbon tube film composite structure covering the metal grid may be treated with an organic solvent, so that the graphene sheet-nanocarbon tube film composite structure and the metal grid are tightly combined and along the metal The grid edge removes the excess graphene sheet-nano carbon tube film composite structure, which is made into a transmission electron microstrip.

The above organic solvent is an organic solvent which is volatile at normal temperature, such as ethanol, methanol, acetone, dichloroethane or chloroform, and ethanol is used in this embodiment. The organic solvent can be directly dropped on the surface of the graphene sheet-nanocarbon tube film composite structure, so that the graphene sheet-nanocarbon tube film composite structure and the metal mesh are tightly combined. Alternatively, the metal mesh covered with the graphene sheet-nanocarbon tube film composite structure may be entirely immersed in a container containing an organic solvent. The step of removing the excess graphene sheet-nanocarbon tube film composite structure other than the metal grid may be performed by focusing a laser beam and irradiating the edge of the metal grid for one week to ablate the graphene sheet-carbon nanotube The membrane composite structure removes excess graphene sheet-nanocarbon tube membrane composite structure outside the metal grid. This step is an optional step.

The preparation method of the TEM micro-gate provided by the embodiment of the invention has the following advantages. First, since the carbon nanotube film and the carbon nanotube film structure formed by the carbon nanotube film are self-supporting, they can be conveniently laid and laminated, and a carbon nanotube film structure can be conveniently covered. On the other surface of the carbon nanotube film structure having a graphene sheet, the two carbon nanotube film structure is sandwiched between the graphene sheets. Secondly, the method of treating the graphene sheet-nanocarbon tube film composite structure by laser, ultraviolet light or high energy particles enables the graphene sheet and the carbon nanotube film to be more firmly bonded by a covalent bond. Again, since the carbon nanotube film structure has a large specific surface area, it has a large viscosity and can adhere well to the metal mesh, and the carbon nanotube film structure and the metal are treated by an organic solvent. The combination of the grid is stronger. Further, the graphene sheet-nanocarbon tube membrane structure can be covered on a plurality of metal grids at one time, and the method is simple and quick, and the graphene sheet-nanocarbon tube membrane structure other than the metal grid can be removed. A TEM microgrid with stable properties was prepared in batches.

Referring to FIG. 4 , FIG. 5 and FIG. 7 , the present invention provides a TEM micro-gate 100 comprising a metal mesh 110 and a graphene sheet-carbon nanotube film composite structure 120 covering the surface of the metal mesh 110 . .

The graphene sheet-nanocarbon tube film composite structure 120 includes at least one carbon nanotube film structure 122 and a plurality of graphene sheets 124 disposed on the surface of the carbon nanotube film structure 122. The carbon nanotube membrane structure 122 includes a plurality of micropores 126, wherein at least one of the micropores 126 is covered by a graphene sheet 124.

Specifically, referring to FIG. 2 and FIG. 3 together, the carbon nanotube film structure 122 includes a plurality of stacked layers of carbon nanotube film. The carbon nanotube film is obtained by drawing from a carbon nanotube array, and comprises a plurality of carbon nanotubes which are oriented substantially in the same direction and arranged parallel to the surface of the carbon nanotube film. The carbon nanotubes are connected end to end by Van der Waals force. The plurality of carbon nanotube films in the carbon nanotube film structure 122 are interdigitated and laminated. Since the carbon nanotubes in each layer are arranged in a preferred orientation in one direction, the carbon nanotubes in the adjacent two layers of carbon nanotube membranes have an intersection angle α, 0° < α≦ 90°. This embodiment is preferably α = 90°.

Referring to FIGS. 5 and 7, the carbon nanotube structure 122 includes a plurality of intersecting nanocarbon lines 128 including carbon nanotubes stacked side by side and gathered by van der Waals force. Further, The nanocarbon line 128 includes carbon nanotubes that are connected end to end by van der Waals force and are arranged in a preferred orientation along substantially the same direction. The intersecting nanocarbon line 128 defines a plurality of micropores 126 in the carbon nanotube membrane structure 122. The size of the micropores 126 of the carbon nanotube membrane structure 122 is related to the number of layers of the carbon nanotube membrane. The number of layers of the carbon nanotube film in the carbon nanotube film structure 122 is not limited, and is preferably 2 to 4 layers. The pores 126 in the carbon nanotube membrane structure 122 may have a size of from 1 nm to 1 μm, and preferably, the pores of 100 nm or less may reach 60% or more.

The graphene sheet 124 includes one or more layers of graphene having a size greater than the size of the micropores 126 in the carbon nanotube membrane structure 122 and completely covering the microholes 126. The graphene sheet 124 has a size of 2 nm to 10 μm. Preferably, the graphene sheet has a size of from 2 nm to 1 μm. In this embodiment, the graphene sheet 124 includes 1 to 3 layers of graphene.

Further, the carbon atoms in the graphene sheet 124 and the carbon atoms in the carbon nanotubes can be bonded by sp3 hybridization, thereby stably fixing the graphene sheet 124 to the carbon nanotube film structure 122. .

Further, the graphene sheet-nanocarbon tube film composite structure 120 may include a plurality of carbon nanotube film structures 122 stacked and a plurality of graphene sheets 124 disposed on adjacent two carbon nanotube film structures 122. between. Referring to FIG. 6, the graphene sheet 124 may be disposed between the two carbon nanotube film structures 122 and sandwiched by the nano carbon line 128 in the two carbon nanotube film structure 122, thereby making the graphene sheet 124 Stabilized on the carbon nanotube membrane structure 122.

The metal mesh 110 is a metal piece formed with one or more through holes 112. The metal mesh 110 can be a metal mesh 110 for transmission electron mirrors. The material of the metal mesh 110 is copper or other metal material. The graphene sheet-nanocarbon tube film composite structure 120 substantially covers the metal grid 110, so that the graphene sheet-carbon nanotube film composite structure 120 can be partially suspended by the metal grid 110, this embodiment The graphene sheet-carbon nanotube film composite structure 120 has the same area and shape as the metal grid 110 and completely covers all the through holes 112 of the metal grid 110. In addition, the aperture of the through hole 112 of the metal mesh 110 is much larger than the size of the micropores 126 of the carbon nanotube film structure 122 and larger than the size of the graphene sheet 124. In this embodiment, the through hole 112 of the metal mesh has a diameter of 10 micrometers to 2 millimeters.

It can be understood that the TEM microgrid 100 can also replace the metal mesh 110 with a mesh made of other materials such as ceramics.

In the embodiment, the TEM micro-gate 100 is applied, and the sample 200 to be observed is disposed on the surface of the TEM micro-gate 100. Specifically, referring to FIG. 8 and FIG. 9 , the sample 200 is disposed on the surface of the graphene sheet 124 covering the micropores 126 of the carbon nanotube film structure 122 . The sample 200 can be a nanoparticle such as a nanowire, a nanosphere or a nanotube. The sample 200 may have a size of less than 1 micron, preferably less than 10 nanometers. Please refer to FIG. 9 and FIG. 10 , which are TEM images of different resolutions obtained by adding a nano-gold dispersion droplet to the surface of the TEM micro-gate 100 and drying under a transmission electron microscope. The black particles in the figure are the nano gold particles to be observed.

The TEM micro-gate 100 provided by the embodiment of the present invention has the following advantages.

First, the graphene sheet 124 functions as a carrier sample 200, and a large amount of the sample 200 can be uniformly distributed on the surface of the graphene sheet 124, which can be used to measure the statistical distribution of the particle size of the sample 200, and observe the self of the sample 200 on the surface of the graphene sheet. Assembly characteristics. Since the graphene sheet 124 covers the micropores 126, the sample 200 can be carried by the graphene sheet 124 to be evenly distributed over the micropores 126 of the carbon nanotube membrane structure 122, thereby improving the transmission electron microstrip. The probability of carrying 100 pairs of samples. Moreover, the particle diameter of the sample to be tested 200 is not limited, for example, only slightly smaller than the micropores 126.

Secondly, it is difficult to prepare a large-sized graphene sheet 124. The size of the graphene sheet 124 prepared by the prior method is less than 10 μm, and therefore, since the carbon nanotube film structure 122 has nano-scale micropores 126 (the size is 1 nm or more, and less than 1 micrometer), the size of the graphene sheet 124 does not need to be too large, and the micropores 126 can be completely covered, so that the effective area of the microgrid 100 for observation can be maximized, thereby avoiding The micropores are too large, causing the graphene sheets 124 to not completely cover the micropores.

Third, the graphene sheet has an extremely thin thickness, and the thickness of the single-layer graphene is about 0.335 nm, and the contrast noise generated in the transmission electron microscope observation is small, so that a higher resolution TEM image can be obtained. In addition, metal grids with small diameter (eg, less than 2 microns) vias must be fabricated by photolithography or other complex and costly processes. In this embodiment, the aperture of the metal mesh 110 does not need to be small, so the cost of the metal grid 110 is greatly reduced.

Fourth, since the carbon nanotube film obtained for drawing from the carbon nanotube array has high purity, it is not necessary to remove impurities by heat treatment. The method for preparing the carbon nanotube film is simple, and is advantageous for reducing the cost of the TEM microgrid 10. In the present embodiment, the transmission electron microstrip microgrid 10 has little interference to the morphology and structural analysis of the sample to be observed carried thereon, and has little influence on the high resolution image of the nanoparticle sample.

Further, since the carbon nanotube film structure 122 and the graphene sheet 124 are both formed by carbon atom bonding and have a similar structure, the carbon nanotube film structure 122 has good matching with the graphene sheet 124. The sp3 covalent bond can be formed by treatment to form a unitary structure, which is convenient for use or long-term storage.

In addition, the graphene sheet-nanocarbon tube film composite structure 120 may include at least two carbon nanotube film structures 122 and sandwich the graphite disposed between the two graphene sheet-carbon nanotube film composite structures 120. Alkene sheet 124. Such a structure allows the TEM microgrid 100 to have a more stable structure for re-use or long-term storage.

It will be understood by those skilled in the art that the micropores in the graphene sheet and the carbon nanotube film structure are rectangular or irregular polygonal structures, and the size of the graphene sheet refers to a point from the edge of the graphene sheet to another point. The maximum linear distance, the size of the micro-hole refers to the maximum linear distance from one point to another point in the micro-hole.

In summary, the present invention has indeed met the requirements of the invention patent, and has filed a patent application according to law. However, the above description is only a preferred embodiment of the present invention, and it is not possible to limit the scope of the patent application of the present invention. Equivalent modifications or variations made by those skilled in the art in light of the spirit of the invention are intended to be included within the scope of the following claims.

100‧‧‧ Transmission electron microscopy
112‧‧‧through hole
110‧‧‧Metal grid
120‧‧‧graphene sheet-nano carbon tube membrane composite structure
122‧‧‧Nano Carbon Membrane Structure
124‧‧‧graphene tablets
126‧‧‧Micropores
128‧‧‧Nano carbon pipeline
200‧‧‧ samples

1 is a schematic flow chart of a method for preparing a transmission electron microstrip micro-gate according to an embodiment of the present invention.

2 is a scanning electron micrograph of a carbon nanotube film in a transmission electron microstrip micro-gate according to an embodiment of the present invention.

3 is a scanning electron micrograph of a structure of a carbon nanotube film formed by a plurality of intersecting carbon nanotube films in a transmission electron microscope micro-gate according to an embodiment of the present invention.

4 is a schematic structural view of a transmission electron microscope micro-gate according to an embodiment of the present invention.

FIG. 5 is a schematic structural view showing a structure of a graphene sheet-nanocarbon tube film in a transmission electron microscope micro-gate according to an embodiment of the present invention.

6 is a schematic view showing the structure of another graphene sheet-nanocarbon tube membrane structure in a transmission electron microscope micro-gate according to an embodiment of the present invention.

7 is a transmission electron micrograph of a graphene sheet-nanocarbon tube membrane structure in a transmission electron microscope micro-gate according to an embodiment of the present invention.

FIG. 8 is a schematic structural view of a TEM micro-gate having a sample on the surface according to an embodiment of the present invention.

Fig. 9 is a transmission electron micrograph of a nano-particle for observation of a transmission electron microstrip micro-gate according to an embodiment of the present invention.

Figure 10 is a high resolution transmission electron micrograph of the nano gold particles observed in the TEM of the embodiment of the present invention.

Claims (23)

A TEM micro-gate comprising a grid, the improvement comprising: further comprising a graphene sheet-nanocarbon tube film composite structure covering the grid, and being suspended by the grid portion, the graphene sheet-nai The carbon nanotube film composite structure comprises at least one carbon nanotube film structure and a plurality of graphene sheets, wherein the carbon nanotube film structure comprises a plurality of micropores, wherein at least one micropores are covered by a graphene sheet. The TEM micro-gate according to claim 1, wherein the graphene sheet has a size of 2 nm to 10 μm. The TEM micro-gate according to claim 2, wherein the graphene sheet has a size of 2 nm to 1 μm. The TEM micro-gate according to claim 1, wherein the graphene sheet comprises 1 to 3 layers of graphene. The TEM micro-gate according to claim 1, wherein the carbon nanotube film structure comprises a plurality of carbon nanotubes arranged in a preferred orientation along substantially the same direction and connected end to end by a van der Waals force. The TEM micro-gate of claim 5, wherein the carbon nanotube film structure comprises a multi-layered carbon nanotube film cross-stacked arrangement. The TEM microgrid according to claim 1, wherein the micropore has a size of 1 nm to 1 μm. The TEM microgrid according to claim 7, wherein the micropores having a size of less than 100 nm account for more than 60% of the total number of micropores. The TEM microgrid according to claim 1, wherein the carbon atoms in the graphene sheet are bonded to the carbon atoms in the carbon nanotube film structure by sp3 hybridization. The TEM micro-gate according to claim 1, wherein the graphene sheet-nanocarbon tube film composite structure comprises a plurality of carbon nanotube film structure stacked and a plurality of graphene sheets are disposed adjacent to each other The two carbon nanotube membrane structures are sandwiched between the adjacent two carbon nanotube membrane structures. The TEM micro-gate according to claim 1, wherein the grid has at least one through hole having a pore diameter of 10 μm to 2 mm. The TEM micro-gate according to claim 1, wherein the material of the mesh is metal or ceramic. A TEM micro-gate comprising a grid, the improvement comprising: further comprising a graphene sheet-nanocarbon tube film composite structure covering the grid, and being suspended by the grid portion, the graphene sheet-nai The carbon nanotube film composite structure comprises at least one carbon nanotube film structure and a plurality of graphene sheets, wherein the carbon nanotube membrane structure comprises a plurality of nano carbon pipeline crossovers and nano carbon pipelines arranged by the plurality of intersections a plurality of micropores formed, wherein at least one of the micropores is covered by a graphene sheet. The TEM microgrid of claim 13, wherein the nanocarbon pipeline comprises carbon nanotubes stacked side by side and gathered by van der Waals force. The TEM microgrid according to claim 14, wherein the nanocarbon pipeline comprises a carbon nanotube arranged end to end by van der Waals force and arranged in a preferred orientation substantially in the same direction. A method for preparing a transmission electron microstrip, comprising the steps of:
Providing a self-supporting carbon nanotube film structure, and a graphene sheet dispersion comprising a plurality of micropores;
The graphene sheet dispersion is infiltrated into the surface of the carbon nanotube film structure;
Drying the carbon nanotube film structure infiltrated by the graphene sheet, thereby compounding the graphene sheet with the carbon nanotube film structure to form a graphene sheet-nanocarbon tube film composite structure; and forming the graphite The ene-nano carbon nanotube film composite structure covers a grid. The method for preparing a TEM micro-gate according to claim 16, wherein the method further comprises the step of treating the at least one carbon nanotube film structure with an organic solvent. The method for preparing a TEM micro-grid according to claim 16, wherein the graphene sheet dispersion is further immersed in the surface of the carbon nanotube film structure, and further comprises covering another carbon nanotube film structure. And forming a sandwich structure on the surface of the carbon nanotube film structure infiltrated by the graphene sheet dispersion. The method for preparing a TEM micro-grid according to claim 16, wherein after drying the carbon nanotube film structure impregnated by the graphene sheet, further comprising irradiating the graphene sheet with laser or ultraviolet light a carbon nanotube film composite structure; or a step of bombarding the graphene sheet-nanocarbon tube film composite structure with high energy particles to bond the graphene sheet to the carbon nanotube. The method for preparing a TEM micro-gate according to claim 16, wherein the graphene sheet-carbon nanotube film composite structure covers the grid, and further comprises treating the graphite with an organic solvent. The olefin-nano carbon nanotube film composite structure and the mesh are tightly combined. The method for preparing a TEM micro-grid according to claim 16, wherein the graphene sheet-nanocarbon tube film composite structure covers the grid, and further comprises removing excess along the edge of the grid. Step of graphene sheet-nano carbon tube film composite structure. The method for preparing a TEM micro-gate according to claim 16, wherein the method of covering the grid with the graphene sheet-carbon nanotube film composite structure further comprises the following steps:
Provide multiple grid spacing arrangements;
The graphene sheet-nanocarbon tube film composite structure is entirely covered in the plurality of meshes; and the graphene sheet-nanocarbon tube film composite structure is disconnected from the adjacent two grids, thereby being disposable A plurality of meshes are formed which are covered with a graphene sheet-nanocarbon tube film composite structure. The method for preparing a TEM micro-gate according to claim 21 or 22, wherein the removing the excess graphene sheet-carbon nanotube film composite structure or disconnecting from between two adjacent grids The method of the graphene sheet-nanocarbon tube film composite structure is to focus and irradiate the graphene sheet-carbon nanotube film composite structure with a laser beam.