TWI411004B - Transmission electron micro-gate and preparation method thereof - Google Patents

Abstract

The invention relates to a transmission electron microscope (TEM) grid. The TEM grid includes a pure carbon grid and at least one carbon nanotube film. The pure carbon grid defines a plurality of holes. The at least one carbon nanotube film covers the plurality of holes of the pure carbon grid.

Description

Transmission electron micro-gate and preparation method thereof

The invention relates to a TEM micro-grid and a preparation method thereof, in particular to a TEM micro-gate based on a carbon nanotube and a preparation method thereof.

In transmission electron microscopy, porous carbon support membranes (microgrids) are important tools 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, when the above-mentioned micro-gate is used to analyze the composition of the TEM high-resolution image of the sample to be tested, the metal mesh often contains a large amount of impurities, such as metal oxides, and the interference of the component analysis of the sample to be tested is large.

Since the early 1990s, nanomaterials represented by carbon nanotubes (see Helical microtubules of graphitic carbon, Nature, Sumio Iijima, vol 354, p56 (1991)) have caused people with their unique structure and properties. Great attention. The application of carbon nanotubes to the fabrication of microgrids is beneficial to reduce the interference of metal grids on the analysis of the components of the sample being tested.

In view of this, it is necessary to provide a TEM micro-grid based on a carbon nanotube and a preparation method thereof, and the TEM micro-grid has less interference to the composition analysis of the sample to be tested.

The TEM microgrid includes a pure carbon grid and at least one carbon nanotube membrane having a plurality of meshes, the at least one carbon nanotube film covering a plurality of the pure carbon grids Mesh.

A method for preparing a transmission electron microstrip, comprising the steps of: providing a pure carbon mesh preform; providing at least one carbon nanotube film, laying at least one carbon nanotube film on the surface of the pure carbon mesh preform And cutting the pure carbon mesh preform and the at least one carbon nanotube film to a predetermined size to form the TEM microgrid.

Compared with the prior art, the TEM microgrid provided by the present invention comprises a pure carbon grid and at least one carbon nanotube film, no metal mesh is required, and the pure carbon grid and at least one carbon nanotube film are relatively pure. It can effectively eliminate the interference of the metal grid in the traditional micro-grid on the analysis of the components of the sample to be tested, which is beneficial to improve the accuracy of component analysis by TEM.

10‧‧‧Transmission electron microscopy

104‧‧‧ at least one carbon nanotube film

102‧‧‧Pure carbon grid

106‧‧‧Mesh

108‧‧‧Micropores

FIG. 1 is a schematic exploded perspective view of a TEM micro-gate according to an embodiment of the present invention.

2 is a schematic perspective view showing the structure of a transmission electron microscope micro-gate according to an embodiment of the present invention.

3 is a cross-sectional structural view of a TEM micro-gate according to an embodiment of the present invention.

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

FIG. 5 is a scanning electron micrograph of a carbon nanotube rolled film in a transmission electron microscope micro-gate according to an embodiment of the present invention.

6 is a scanning electron micrograph of a carbon nanotube film in a TEM microgrid according to an embodiment of the present invention.

FIG. 7 is a schematic flow chart of a method for preparing a TEM micro-gate according to an embodiment of the present invention.

The TEM micro-gate of the present invention and its preparation method will be further described in detail below with reference to the accompanying drawings.

Referring to FIG. 1 and FIG. 3 together, the present invention provides a TEM micro-gate 10. Transmission electron microstrip 10 includes a pure carbon grid 102 and at least one carbon nanotube membrane 104. The at least one carbon nanotube film 104 is disposed on the surface of the pure carbon grid 102. The pure carbon grid 102 and the at least one carbon nanotube membrane 104 are relatively pure. The pure carbon grid 102 can be in the form of a disk having a diameter of about 3 mm.

The pure carbon grid 102 is a self-supporting structure and has a plurality of meshes 106. The self-supporting pure carbon grid 102 does not require a large area of carrier support, but can maintain its own sheet-like structure as long as it provides support force on both sides. The at least one carbon nanotube film 104 covers the plurality of meshes 106 of the pure carbon grid 102. The shape of the mesh 106 is not limited. When the plurality of meshes 106 are formed by laser irradiation according to different preparation methods, laser beams of different shapes or nets formed by different laser irradiation modes are selected. The shape of the holes 106 may be circular, square, elliptical, or the like. The size of the mesh 106 is not limited and can be adjusted according to actual application requirements. Preferably, the mesh 106 is a circular aperture. The mesh 106 can be a through hole, i.e., it can extend from one surface of the pure carbon grid 102 to another surface opposite the surface. The arrangement of the meshes 106 is not limited. The distance between the meshes 106 can be equal or unequal. Preferably, the mesh 106 is evenly distributed on the surface of the pure carbon mesh 102 or the plurality of meshes 106 are distributed in an array on the surface of the pure carbon mesh 102, and between adjacent meshes 106 The distance is equal. The distance between adjacent meshes 106 can be greater than 1 micron. The pure carbon grid 102 can have a thickness of about 3 to 20 microns. The mesh 106 has a size of about 10 microns to 200 microns. The material of the pure carbon grid 102 may be carbon black or carbon nanotubes.

When the material of the pure carbon grid 102 is carbon black, the pure carbon grid 102 is a disk-shaped carbon black film. The size of the mesh 106 is preferably from 30 micrometers to 200 micrometers.

When the material of the pure carbon grid 102 is a carbon nanotube, the pure carbon grid 102 is a disk-shaped carbon nanotube structure. The disk-shaped carbon nanotube structure is a self-supporting structure and has certain supporting properties. Preferably, the disk-shaped carbon nanotube structure has better support properties. The self-supporting disk-shaped carbon nanotube structure does not require a large-area carrier support, and as long as the supporting force is provided on both sides, it can be suspended as a whole to maintain its own sheet-like structure. The disk-shaped carbon nanotube structure can be Includes at least one layer of carbon nanotube film. The number of layers of the carbon nanotube film constituting the disk-shaped carbon nanotube structure is determined according to the thickness of the single-layer carbon nanotube film, and the wafer-shaped carbon nanotube structure has good support performance. . It can be understood that the smaller the thickness of the single-layer carbon nanotube film, the more the number of layers of the carbon nanotube film in the disk-shaped carbon nanotube structure; the greater the thickness of the single-layer carbon nanotube film, The fewer the number of layers of the carbon nanotube film in the disk-shaped carbon nanotube structure. The adjacent two layers of carbon nanotube membranes can be tightly bonded by van der Waals force. The carbon nanotube film may be a carbon nanotube film, a carbon nanotube film or a carbon nanotube film.

The carbon nanotube flocculation membrane comprises a plurality of carbon nanotubes which are intertwined and uniformly distributed. The carbon nanotubes are attracted and entangled with each other by van der Waals force to form a network structure to form a self-supporting carbon nanotube flocculation film. See FIG. 4 for a scanning electron micrograph. The carbon nanotube flocculation membrane is isotropic. The carbon nanotube flocculation membrane can be obtained by flocculation treatment on a carbon nanotube array. The carbon nanotube flocculation film and the preparation method thereof are described in the Chinese Patent Application No. 200844041 published on November 16, 2008. To save space, all of the technical disclosures in the application are also considered to be part of the disclosure of the present application. It is to be noted that the carbon nanotube flocculation membrane is not limited to the above preparation method. The carbon nanotube film has a thickness of from 1 micrometer to 2 millimeters. The carbon nanotube structure may include only one layer of carbon nanotube flocculation membrane, and its thickness is ensured to ensure better support performance.

The carbon nanotube rolled film comprises a plurality of carbon nanotubes arranged in disorder, arranged in a preferred orientation in one direction or in a preferred orientation in a plurality of directions, and the adjacent carbon nanotubes are combined by a van der Waals force. The carbon nanotube rolled film can be obtained by extruding the carbon nanotube array in a direction perpendicular to the substrate grown by the array of carbon nanotubes by using a planar indenter, and the carbon nanotube is rolled at this time. The carbon nanotubes in the membrane are disorderly arranged, and the carbon nanotube membrane is isotropic; the carbon nanotube membrane can also be rolled in a fixed direction by a roller-shaped indenter. Obtained by a carbon nanotube array, in which the carbon nanotubes in the carbon nanotube rolled film are arranged in the preferred orientation in the fixed direction The carbon nanotube rolled film can also be obtained by rolling the carbon nanotube array in different directions by a roller-shaped indenter, and the carbon nanotube along the carbon nanotube film is At different times, the carbon nanotube rolled film may include a plurality of portions, and the carbon nanotubes in each portion are arranged in a preferred orientation in one direction, and the nanocarbon in the adjacent two portions The arrangement of the tubes can be different. See Figure 5 for a scanning electron micrograph of the carbon nanotube rolled film. The carbon nanotube rolled film and the preparation method thereof are described in the Chinese Patent Application No. 200900348 published on January 1, 2009. To save space, all of the technical disclosures in the application are also considered to be part of the disclosure of the present application. The carbon nanotube rolled film has a thickness of 1 micrometer to 1 millimeter. The carbon nanotube structure may include only one layer of carbon nanotube rolled film, and its thickness is adjusted to achieve better support performance.

Referring to FIG. 6, the carbon nanotube film is a self-supporting structure composed of a plurality of carbon nanotubes. The plurality of carbon nanotubes are arranged in a preferred orientation along the same direction. The preferred orientation means that the overall extension direction of most of the carbon nanotubes in the carbon nanotube film is substantially in the same direction. Moreover, the overall extension direction of the majority of the carbon nanotubes is substantially parallel to the surface of the carbon nanotube film. Further, most of the carbon nanotubes in the carbon nanotube film are connected end to end by Van der Waals force. Specifically, each of the carbon nanotubes of the majority of the carbon nanotubes extending in the same direction in the carbon nanotube film is connected end to end with the carbon nanotubes adjacent in the extending direction by van der Waals force . Of course, there are a small number of randomly arranged carbon nanotubes in the carbon nanotube film, and these carbon nanotubes do not significantly affect the overall orientation of most of the carbon nanotubes in the carbon nanotube film. The self-supporting carbon nanotube film does not require a large-area carrier support, and as long as the support force is provided on both sides, it can be suspended in the whole to maintain its own film state, that is, the carbon nanotube film is placed (or When fixed on two supports arranged at a certain distance, the carbon nanotube film located between the two supports can be suspended to maintain its own film state. The self-supporting is mainly achieved by the presence of continuous carbon nanotubes extending through the ends of the van der Waals force through the carbon nanotube film.

Specifically, most of the carbon nanotubes extending substantially in the same direction in the carbon nanotube film are not absolutely linear, and may be appropriately bent; or may not be completely aligned in the extending direction, and may be appropriately deviated from the extending direction. Therefore, it is not possible to exclude partial contact between the carbon nanotubes juxtaposed in the majority of the carbon nanotubes extending substantially in the same direction of the carbon nanotube film. Specifically, each carbon nanotube film comprises a plurality of carbon nanotube segments arranged in a continuous and preferential orientation. The plurality of carbon nanotube segments are connected end to end by Van der Valli. Each of the carbon nanotube segments includes a plurality of substantially parallel carbon nanotubes, and the plurality of substantially parallel carbon nanotubes are tightly coupled by van der Waals force. The carbon nanotube segments have any length, thickness, uniformity, and shape. The carbon nanotubes in the carbon nanotube film are arranged in a preferred orientation in the same direction. The carbon nanotube film is obtained by drawing from a carbon nanotube array. The thickness of the carbon nanotube film is from 0.5 nm to 100 μm depending on the height and density of the carbon nanotubes in the carbon nanotube array. The width of the carbon nanotube film is related to the size of the carbon nanotube array for pulling the carbon nanotube film, and the length is not limited. When the thickness of the carbon nanotube film is from 0.5 nm to 100 μm, the carbon nanotube structure may include 10 or more laminated carbon nanotube films. Preferably, the carbon nanotube structure may include a carbon nanotube film disposed in a layer of more than 100 layers.

When the disk-shaped carbon nanotube structure comprises a plurality of carbon nanotube membranes and the carbon nanotubes in each of the carbon nanotube membranes are arranged in a preferred orientation in the same direction, in the adjacent two layers of carbon nanotube membranes The arrangement of the carbon nanotubes may be the same or different. Specifically, the carbon nanotubes in the adjacent carbon nanotube film have an intersection angle α between the α and the α is greater than or equal to 0 degrees and less than or equal to 90 degrees. When the carbon nanotubes in the plurality of carbon nanotube membranes in the disk-shaped carbon nanotube structure have an intersection angle α and α is not equal to 0 degrees, that is, when a plurality of carbon nanotube membranes are disposed at the intersection The carbon nanotubes are interwoven to form a network structure, which enhances the mechanical properties of the wafer-shaped carbon nanotube structure.

It can be understood that the intersection of a plurality of carbon nanotube membranes does not require any two adjacent layers of carbon nanotube membranes to be intersected, that is, the majority of carbon nanotubes in the adjacent two layers of carbon nanotube membranes are allowed to exist. arrangement The same direction, but it is necessary to ensure that the intersection angle between the arrangement directions of the majority of the carbon nanotubes in at least two layers of the carbon nanotube film is greater than 0 degrees and less than or equal to 90 degrees.

In the embodiment, the pure carbon grid 102 is a disk-shaped carbon nanotube structure with a self-supporting structure formed by the intersection of 100 layers of carbon nanotube film. The carbon nanotubes in the adjacent two layers of carbon nanotube film have an angle of intersection α, and the α is equal to 90 degrees. The mesh 106 is a circular hole having a pore size between 30 microns and 150 microns.

The at least one carbon nanotube film 104 covers a plurality of meshes 106 in the pure carbon grid 102. The at least one carbon nanotube film 104 covering the mesh 106 is suspended at the mesh. At least one carbon nanotube film 104 suspended at each of the meshes corresponds to an electron transmissive portion. The electron transmissive portion is used to carry the sample to be tested for transmission electron microscope observation. The at least one carbon nanotube film 104 is preferably a carbon nanotube film. When there are two or more layers of carbon nanotube film covering the plurality of meshes 106, the two or more layers of carbon nanotube film are preferably arranged in a cross. The angle of intersection between the two or more layers of carbon nanotube drawn films disposed at the intersection is preferably 90 degrees. Since the plurality of carbon nanotube film is disposed at the intersection, the carbon nanotubes in the different layers of the carbon nanotube film are interwoven to form a network structure, so that the mechanical properties of the at least one carbon nanotube film 104 are obtained. Reinforce, while the at least one carbon nanotube film 104 has a plurality of uniform and regularly arranged micropores 108, the pore size of the micropores 108 is related to the number of layers of the carbon nanotube film, and the number of layers is larger, the micropores The smaller the aperture of 108. The pores 108 may have a pore size of from 1 nm to 1 μm. Furthermore, the thickness of the at least one carbon nanotube film 104 is preferably less than 100 microns. In this embodiment, two layers of carbon nanotube film stretched across the plurality of meshes 106 in the TEM micro-gate 10.

Since the TEM micro-gate 10 in this embodiment is composed of a pure carbon grid 102 and at least one carbon nanotube film 104, it does not contain a metal mesh, and the pure carbon grid 102 and at least one carbon nanotube film 104 are relatively Pure, no interference to the analysis of the components of the sample to be tested, therefore, can effectively eliminate the interference of the metal grid in the traditional micro-grid on the analysis of the components of the sample to be tested, thereby facilitating the component analysis of the transmission electron microscope 10 Time accuracy.

In the present embodiment, the TEM microgrid 10 is applied to the surface of the at least one carbon nanotube film 104 when applied. When the size of the material sample is larger than the micropores 108 of the at least one carbon nanotube film 104, the micropores 108 can support the material sample. The material sample can be viewed through an electron transmissive portion corresponding to the mesh 106. And when the material sample has a smaller size than the micropores 108, especially when the material sample is a nanoparticle having a particle diameter of less than 5 nm, the material sample may pass through at least one carbon nanotube film 104. The adsorption of the carbon nanotubes is stably adsorbed on the surface of the carbon nanotube wall, and at this time, the material sample can also be observed through the electron-transmissive portion corresponding to the mesh 106. Thus, the TEM microgrid 10 of the present invention can be used to observe a sample of nanoparticle material having a particle diameter of less than 5 nm, thereby eliminating the amorphous carbon film in the conventional microgrid and the nanoparticle having a particle diameter of less than 5 nm. The effect of TEM on high resolution image observation.

Referring to FIG. 7, the present invention further provides a method for fabricating the above TEM micro-gate 10, the method comprising the following steps:

Step 1. Provide a pure carbon grid preform.

When the pure carbon mesh preform is a sheet carbon black film, the method for preparing the pure carbon mesh preform comprises the following steps: First, a carbon slurry and a support are provided.

The carbon slurry can include a liquid mixture and carbon black. Wherein, the liquid mixture may comprise 15-95% by mass (i.e., 15-95% by weight) of the carbon paste, and the carbon black may comprise 5-85% by weight of the carbon slurry. The liquid mixture can include a solvent and a viscosity modifier. The solvent may be water, an alcohol or a quinone compound or the like. The alcohol may be methanol, ethanol, propanol, butanol, pentanol, heptanol, ethylene glycol, propylene glycol, glycerol, benzyl alcohol or allyl alcohol. The terpenoids are isobornyl, borneol, ketone, sterol, benzyl, menthone, menthol or terpineol. The dissolution The weight percentage of the agent may range from 20 to 99.5 wt% of the liquid mixture. The viscosity modifier may be starch or a salt thereof, cellulose or a salt thereof, or a polyether. The cellulose or a salt thereof may be methyl cellulose, ethyl cellulose, cellulose acetate or sodium carboxymethyl cellulose. The polyethers are polyethylene glycol, polypropylene glycol, polyglycerol, or a copolymer of ethylene glycol and propylene glycol, and the like. The viscosity modifier may be present in an amount of from 0.5 to 40% by weight of the liquid mixture.

Alternatively, the liquid mixture may further comprise a surfactant or a binder. The surfactant may be a polyoxyethylene ether surfactant such as polyethylene glycol octylphenyl ether (Triton X 100) or octylphenol polyoxyethylene ether (Triton X405). The surfactant may comprise from 0.5 to 20% by weight of the liquid mixture. The binder may be added in an amount of from 0.5 to 20% by weight of the liquid mixture. The binder may be a powdered tin dioxide or a tin dioxide colloid.

The carbon slurry can be prepared by dissolving a viscosity modifier in a solvent, adding it uniformly, adding carbon black, and then mechanically stirring. The mechanical agitation time is about 3-6 hours. In this embodiment, 0.2 g of ethyl cellulose can be dissolved in 15 ml of isopropanol and mechanically stirred to uniformly mix, then about 6 g of carbon black powder is added, and mechanical stirring is continued for about 4 hours to form the Carbon slurry.

The support can be used to support the carbon slurry during preparation. The material of the support is not limited. The support may be a glass substrate or a ceramic sheet. In this embodiment, the support body is a glass substrate.

Next, the carbon paste is printed onto the support.

The method of printing the carbon paste to the support may be a screen printing method, a knife coating method, a spin coating film, a dropping film or a pulling method. In this embodiment, the carbon paste is printed to the support by a screen printing method.

Again, the carbon slurry is dried to form a pure carbon film. Can be taken to dry or heat at room temperature To dry the carbon slurry.

Finally, the pure carbon film is perforated according to a predetermined pattern, and the pure carbon film and the support are separated to form the pure carbon mesh preform.

A method of perforating the pure carbon film includes a laser perforation method. Specifically, the method for performing punching on the pure carbon film includes the steps of: providing a focused laser beam; irradiating the focused laser beam to the pure carbon film point by point according to a predetermined pattern, thereby forming a plurality of meshes 106. The laser beam can be generated by a conventional argon ion laser or carbon dioxide laser. The laser beam has a power of 5 to 30 watts (W), preferably 18 watts. Specifically, the pulsed laser beam can be selected to form a plurality of cells 106 by irradiating the pure carbon film by point-by-point scanning. The so-called "interval illumination" means that when the pure carbon film is subjected to laser drilling, the laser beam is intermittently irradiated and irradiated to different positions of the pure carbon film, and the different positions are separated by a certain distance to It is ensured that a plurality of spaced-apart meshes 106 are formed on the pure carbon film. The plurality of cells 106 are distributed in an array. The shape of the mesh 106 is not limited and may be circular, square or elliptical. In this embodiment, the mesh 106 has a circular shape.

When the material of the pure carbon mesh preform is a carbon nanotube, the preparation method of the pure carbon grid 102 includes the following steps: First, a sheet-shaped carbon nanotube structure is provided.

The sheet-like carbon nanotube structure is composed of at least one carbon nanotube film. The carbon nanotube film may be a carbon nanotube film, a carbon nanotube film or a carbon nanotube film. In this embodiment, the sheet-shaped carbon nanotube structure can be formed by laminating and cross-setting a plurality of carbon nanotube films, which are directly dried from a carbon nanotube array. Fara takes it. The method for preparing the carbon nanotube film comprises the steps of: providing a carbon nanotube array and extracting at least one carbon nanotube film having a certain width and length from the carbon nanotube array.

The carbon nanotube array can be a super-sequential carbon nanotube array. In this embodiment, the method for preparing the carbon nanotube array adopts a chemical vapor deposition method, and the specific steps thereof include: (a) providing a flat substrate, the substrate may be selected from a P-type or N-type germanium substrate, or may be formed. The ruthenium substrate having an oxide layer is preferably a 4-inch ruthenium substrate in this embodiment; (b) a catalyst layer is uniformly formed on the surface of the substrate, and the catalyst layer material may be selected from iron (Fe), cobalt (Co), and nickel (Ni). Or one of the alloys of any combination thereof; (c) annealing the substrate on which the catalyst layer is formed in air at 700 to 900 ° C for about 30 minutes to 90 minutes; (d) placing the treated substrate in a reaction furnace It is heated to 500-740 ° C in a protective gas atmosphere, and then reacted with a carbon source gas for about 5 to 30 minutes to grow a super-aligned carbon nanotube array having a height of 200 to 400 μm. The super-sequential carbon nanotube array is a plurality of pure carbon nanotube arrays formed of carbon nanotubes that are parallel to each other and perpendicular to the substrate. The super-sequential carbon nanotube array contains substantially no impurities such as amorphous carbon or residual catalyst metal particles, etc., by controlling the growth conditions described above. The carbon nanotubes in the array of carbon nanotubes are in close contact with each other to form an array by van der Waals force.

In the present embodiment, the carbon source gas may be a chemically active hydrocarbon such as acetylene, and the protective gas may be nitrogen, ammonia or an inert gas.

The step of extracting the carbon nanotube film from the carbon nanotube array by using a stretching tool comprises the following steps: (a) selecting a plurality of carbon nanotube segments of a certain width from the carbon nanotube array. In this embodiment, it is preferred to contact the carbon nanotube array with a tape having a certain width to select a plurality of carbon nanotube segments of a certain width; (b) to stretch at a certain speed along a growth direction substantially perpendicular to the growth direction of the carbon nanotube array. A plurality of carbon nanotube segments are formed to form the above-mentioned carbon nanotube film.

During the above stretching process, the plurality of carbon nanotube segments are gradually separated from the substrate in the stretching direction under the action of the tensile force, and the selected plurality of carbon nanotube segments are respectively associated with the other naphthalenes due to the van der Waals force. The carbon nanotube segments are continuously pulled out end to end to form a carbon nanotube film. The carbon nanotube film is a plurality of carbon nanotube segments arranged in the stretching direction A carbon nanotube film having a certain width is formed. The width of the carbon nanotube film is related to the size of the substrate on which the carbon nanotube array is grown. The length of the carbon nanotube film is not limited and can be obtained according to actual needs.

The step of laminating and cross-setting a plurality of carbon nanotube film may specifically include the following steps: First, a substrate is provided. The substrate has a flat surface and the material is not limited. In this embodiment, the substrate can be a ceramic sheet.

Next, the above-mentioned carbon nanotube film is laminated in this order and laid on the surface of the substrate.

Since the carbon nanotubes are relatively pure and have a large specific surface area, the carbon nanotube film obtained by directly drawing from the carbon nanotube array has good viscosity. The carbon nanotube film can be directly laid on the surface of the substrate or the surface of the other carbon nanotube film. The stacked and cross-connected, that is, in the laminated carbon nanotube film, the carbon nanotubes in the plurality of carbon nanotube films have an intersection angle α and α is not equal to 0 degrees. The two adjacent layers of carbon nanotubes are tightly bonded by van der Waals force.

Again, the sheet-like carbon nanotube structure is laser perforated to form a plurality of meshes 106.

In this embodiment, the manner of forming the plurality of cells 106 may specifically include the steps of: providing a focused laser beam, and illuminating the focused laser beam line by line to the sheet-shaped nanometer in a predetermined pattern. In the carbon tube structure, the carbon nanotubes in the sheet-like carbon nanotube structure at the position where the laser beam is irradiated are ablated, thereby forming a plurality of meshes 106. The plurality of cells 106 are distributed in an array. The shape of the mesh 106 is not limited and may be circular, square or elliptical. In this embodiment, the mesh 106 has a circular shape. The laser beam can be generated by a conventional argon ion laser or carbon dioxide laser. The laser beam has a power of 5 to 30 watts (W), preferably 18 watts.

Specifically, the pulsed laser beam can be selected to form a plurality of cells 106 on the surface of the sheet-shaped carbon nanotube structure by progressive line-by-point scanning according to a predetermined pattern. The plurality of meshes 106 can be Distributed in an array. Specifically, the following two ways can be implemented:

Method 1: Fixing the sheet-shaped carbon nanotube structure, moving the laser beam, and irradiating the laser beam to the surface of the sheet-shaped carbon nanotube structure according to a predetermined pattern.

Method 2: Fixing the laser beam, moving the sheet-shaped carbon nanotube structure, and irradiating the laser beam to the surface of the sheet-shaped carbon nanotube structure according to a predetermined pattern.

It can be understood that the above moving and illuminating steps can be controlled by a computer program. The so-called "interval illumination" means that when the sheet-shaped carbon nanotube structure is laser-perforated, the laser beam is intermittently irradiated and irradiated to different positions of the sheet-shaped carbon nanotube structure, the difference The locations are spaced apart by a distance to ensure that a plurality of spaced apart cells 106 are formed in the sheet of carbon nanotube structures. The meshes 106 are distributed in an array. The mesh 106 can be a through hole, that is, the carbon nanotubes in the mesh 106 can remain. It can be understood that a part of the carbon nanotubes may remain in the mesh 106, and the partial carbon nanotubes can also be used to support the sample to be tested.

Step 2, providing at least one carbon nanotube film 104, and laying at least one carbon nanotube film 104 on the surface of the pure carbon mesh 102.

The at least one carbon nanotube film 104 is preferably a carbon nanotube film, the preparation method of the carbon nanotube film and the preparation method of the carbon nanotube film constituting the sheet carbon nanotube structure the same.

Since the carbon nanotubes are relatively pure and have a large specific surface area, the carbon nanotube film obtained by directly drawing from the carbon nanotube array has good viscosity. The carbon nanotube film can be directly laid on the surface of the pure carbon grid 102 or the surface of another carbon nanotube film. When a plurality of carbon nanotube film is laid on the surface of the pure carbon grid 102, the plurality of carbon nanotube films may be laminated on the surface of the pure carbon grid 102 in a stack. The two adjacent layers of carbon nanotubes are tightly bonded by van der Waals force.

In this embodiment, four layers of carbon nanotube film are sequentially laminated and disposed on the pure carbon grid 102. surface. The angle between the carbon nanotubes in the adjacent two layers of carbon nanotube film is 90 degrees. The four-layer carbon nanotube film has a plurality of micropores 108. The pores 108 may have a pore size of from 1 nm to 1 μm.

Further, the at least one carbon nanotube film 104 and the pure carbon grid 102 may be treated with an organic solvent. 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 the organic solvent is specifically: dropping the organic solvent on the surface of the at least one carbon nanotube film 104 and the pure carbon mesh 102 through a test tube, or alternatively, the at least one carbon nanotube film 104 and the pure The carbon grid 102 is immersed in a container containing an organic solvent to infiltrate. After the organic solvent treatment, the pure carbon grid 102 composed of carbon nanotubes is side by side and adjacent carbon nanotubes are gathered, and the pure carbon grid 102 has good mechanical strength. After the at least one carbon nanotube film 104 is treated with an organic solvent, a portion of adjacent carbon nanotubes may aggregate to form a bundle of carbon nanotubes. Since the carbon nanotubes in the adjacent two carbon nanotube membranes have an intersection angle α and 0<α≦90°, the carbon nanotube bundles in the at least one carbon nanotube film 104 after the organic solvent treatment are mutually Crossing, thereby forming a plurality of microholes 108. The microholes 108 are preferably less than 10 microns in size, preferably less than 1 micron. It can be understood that the more the number of at least one carbon nanotube film 104 stacked on the pure carbon grid 102, the smaller the size of the micropores 108. Therefore, the desired size of the micropores 108 can be obtained by adjusting the number of the carbon nanotube membranes. Further, the at least one carbon nanotube film 104 may be combined with the pure carbon mesh 102 by an organic solvent treatment, so that the at least one carbon nanotube film 104 is more firmly fixed to the pure carbon grid 102. on.

Step 3: cutting the at least one carbon nanotube film 104 and the pure carbon grid 102 according to a predetermined size to form the TEM microgrid 10.

First, a focused laser beam is provided, and the focused laser beam is irradiated onto the surface of the at least one carbon nanotube film 104 and the pure carbon grid 102 to be cut to a predetermined size. In this embodiment, the laser beam can be generated by a conventional argon ion laser or a carbon dioxide laser, and the power is 5 to 30 watts (W). It is preferably 18W. Specifically, the laser beam can be directly focused on the surface of the at least one carbon nanotube film 104 and the pure carbon grid 102 from a front surface by focusing on a lens. It can be understood that the laser beam can be focused by vertical illumination or oblique illumination. On the surface of the at least one carbon nanotube film 104 and the pure carbon grid 102. The at least one carbon nanotube film 104 and the pure carbon grid 102 can absorb the energy of the laser beam to react with and decompose the oxygen in the air, so that at least one carbon nanotube film 104 having a predetermined size and pure The carbon grid 102 is disconnected from other parts. In this embodiment, after cutting, at least one carbon nanotube film 104 and a pure carbon mesh 102 having a diameter of about 3 mm are obtained.

It can be understood that the above cutting step can also be implemented by means of illuminating the sheet-shaped carbon nanotube structure at intervals, such as fixing the at least one carbon nanotube film 104 and the pure carbon grid 102, and moving the laser beam. Or a fixed laser beam, moving the at least one carbon nanotube film 104 and the pure carbon grid 102 to achieve. In addition, the time during which the laser beam is focused and irradiated in the cutting step may be slightly longer than the time when the laser beam is focused and irradiated during laser drilling of the sheet-shaped carbon nanotube structure, so as to realize the sheet-shaped nai at the irradiation point. The carbon nanotube structure is completely separated from other parts of the sheet-like carbon nanotube structure. This embodiment is not limited to the above-described laser processing method, and other methods in the prior art, such as physical or chemical etching, can also be used to cut the at least one carbon nanotube film 104 and the pure carbon grid 102.

It can be understood that the above steps can achieve rapid mass production of the TEM microgrid 10 by cutting at least one carbon nanotube film 104 and a pure carbon grid 102 of a larger size.

The TEM micro-gate provided by the embodiment of the invention and the preparation method thereof have the following advantages: First, the TEM micro-gate is composed of a pure carbon grid and at least one carbon nanotube film, without a metal mesh, and the The pure carbon grid and at least one carbon nanotube film are relatively pure, which can effectively eliminate the interference of the metal grid in the traditional micro-grid on the analysis of the components of the sample to be tested, thereby facilitating the improvement of the composition analysis by the transmission electron microscope. degree. Secondly, the TEM microgrid provided by the embodiment of the present invention provides a pure carbon grid and at least one carbon nanotube film and lays the at least one carbon nanotube film on the pure carbon. The surface of the mesh is prepared without an evaporation process, so the preparation method is relatively simple.

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.

10‧‧‧Transmission electron microscopy

104‧‧‧ at least one carbon nanotube film

102‧‧‧Pure carbon grid

Claims (18)

A transmission electron microstrip microgrid comprising a pure carbon grid and at least one carbon nanotube membrane, the pure carbon grid being a self-supporting structure, the pure carbon grid having a plurality of meshes, At least one carbon nanotube film covers a plurality of meshes of the pure carbon grid. The TEM microgrid according to claim 1, wherein the pure carbon mesh has a thickness of 3 micrometers to 20 micrometers, and the mesh has a pore diameter of 10 micrometers to 200 micrometers. The TEM microgrid according to claim 1, wherein the pure carbon grid is a disk-shaped carbon black film. The TEM microgrid according to claim 1, wherein the pure carbon grid is a disk-shaped carbon nanotube structure, and the wafer-shaped carbon nanotube structure is a self-supporting structure composed of a carbon nanotube. The TEM microgrid according to claim 1, wherein the carbon nanotube film is obtained by direct dry extraction from a carbon nanotube array. The TEM microgrid according to claim 1, wherein the carbon nanotube film is composed of a plurality of carbon nanotubes, and the plurality of carbon nanotubes are arranged in a preferred orientation in the same direction. The TEM microgrid according to claim 6, wherein the majority of the carbon nanotubes in the carbon nanotube film are connected end to end by Van der Waals force. The TEM micro-gate of claim 5, wherein the TEM micro-gate comprises a plurality of stacked and interdigitated carbon nanotube films covering a plurality of meshes of the pure carbon grid. The TEM microgrid according to claim 1, wherein the at least one carbon nanotube film covering the mesh is suspended at the mesh. The TEM microgrid according to claim 9, wherein the at least one carbon nanotube film suspended at the mesh has a plurality of micropores having a pore diameter of 1 nm to 1 μm. A method for preparing a transmission electron microstrip, comprising the following steps: Providing a pure carbon mesh preform; providing at least one carbon nanotube film, laying at least one carbon nanotube film on the surface of the pure carbon mesh preform; and cutting the pure carbon mesh prefabricated according to a predetermined size And the at least one carbon nanotube film forms the TEM microgrid. The method for preparing a TEM micro-grid according to claim 11, wherein the method for preparing the pure carbon mesh preform comprises the steps of: providing a carbon paste and a support; and printing the carbon paste to the a support body; drying the carbon slurry to form a pure carbon film; and perforating the pure carbon film according to a predetermined pattern, and separating the pure carbon film from the support to form the pure carbon mesh Prefabricated body. The method for producing a TEM micro-grid according to claim 12, wherein the carbon slurry is a mixture of carbon black, a viscosity modifier, and a solvent. The method for preparing a TEM micro-gate according to claim 12, wherein the step of puncturing the pure carbon film according to a predetermined pattern comprises the steps of: providing a focused laser beam; The beam of light is irradiated to the pure carbon film line by line at a point-by-point interval according to a predetermined pattern, and the pure carbon film at the irradiation position is ablated to form a plurality of meshes. The method for preparing a TEM micro-grid according to claim 11, wherein the method for preparing the pure carbon mesh preform comprises the steps of: providing a sheet-shaped carbon nanotube structure; and facing the sheet according to a predetermined pattern The carbon nanotube structure is perforated to form a plurality of meshes. The method of producing a TEM micro-grid according to claim 14 or 15, wherein the plurality of meshes are distributed in an array. A method of producing a TEM microgrid according to claim 11, wherein the predetermined size is cut The step of cutting the pure carbon mesh preform and the at least one carbon nanotube film specifically includes the steps of: providing a focused laser beam; and irradiating the focused laser beam to the pure carbon mesh prefabrication according to a predetermined size And the at least one carbon nanotube film forms the TEM microgrid. The method of producing a TEM micro-gate according to claim 17, wherein the TEM micro-gate is in the form of a disk having a diameter of 3 mm.