A method for preparing nanomaterial transmission electron microscope samples by using single-walled carbon nanotube film transfer

Abstract

The present invention relates to the field of transmission electron microscope sample preparation, and specifically to a method for preparing transmission electron microscope samples of nanomaterials by transferring single-walled carbon nanotube films. First, a single-walled carbon nanotube film with high purity, low catalyst residue and high transmittance prepared by floating catalyst chemical vapor deposition is pressed onto the nanomaterial on a substrate, and the filter membrane is removed after being moistened with alcohol; the substrate is etched in an etching solution, and the single-walled carbon nanotube film and the nanomaterial are combined with van der Waals forces to form a composite film; then the composite film is transferred to clean water for cleaning, and finally it is picked up using a carrier net or a support ring, and washed and dried by dripping alcohol to obtain a transmission electron microscope sample of the nanomaterial. The present invention solves the problem that it is difficult to cleanly and losslessly transfer nanoparticles or two-dimensional materials on a substrate to prepare transmission samples, and avoids the high-temperature heating process and organic polymer residues when traditionally transferring nanomaterials using organic polymers.

Description

Technical Field

[0001] The present invention relates to the field of transmission electron microscope sample preparation, and specifically to a method for preparing a transmission electron microscope sample of a nano material by transferring a single-walled carbon nanotube film. The method utilizes the van der Waals force between the single-walled carbon nanotube film and the nano material and the self-supporting property of the single-walled carbon nanotube film to transfer the nano material on a substrate to prepare the transmission electron microscope sample. The high light transmittance of the single-walled carbon nanotube is utilized to allow an electron beam to pass through the film, thereby facilitating clear transmission electron microscope characterization of the sample. Background Art

[0002] Transmission electron microscope (TEM) is a precision electronic instrument that mainly studies the microstructure of solid samples. It has extremely high resolution. With the development of science and technology, the structure of materials tends to be micronized, and the structural characterization of micronized samples becomes more and more important. Therefore, TEM has a wide range of applications in fields such as materials science.

[0003] Sample preparation is crucial in transmission electron microscopy analysis. Whether or not a clear transmission electron microscopy photograph can be obtained depends largely on the success of sample preparation. However, due to the high requirements of transmission electron microscopy on samples, sample preparation for transmission electron microscopy has always been one of the difficulties that plagues scientific researchers. The main requirements for transmission electron microscopy samples are: (1) The area of ​​the sample to be observed must be "transparent" to the electron beam; (2) The sample must be firm and have a certain degree of radiation resistance; (3) The sample should have a certain degree of conductivity to avoid charge accumulation affecting the characterization; (4) During the sample preparation process, the sample structure must not be destroyed and contamination must not be introduced.

[0004] Nanomaterials, such as nanoparticles or two-dimensional nanomaterials, are tiny in size and naturally "transparent" to electron beams. However, it is difficult for such nanomaterials to be self-supporting, and they often need to be attached to a certain substrate during their preparation. For example, the CVD growth of graphene needs to be attached to copper foil, platinum sheet, etc. The preparation of some nanoparticles requires the precursor to be loaded on a substrate (such as a silicon substrate), and then the structure and size of the nanoparticles are controlled through physical and chemical treatment processes. These two-dimensional materials and nanoparticles have strong interactions with the substrate, which creates great difficulties for the preparation of transmission electron microscope samples. (See literature: Literature 1, Baram G and Kaplan WD. Quantitative HRTEM analysis of FIB prepared specimens[J]. Journal of Microscopy, 2008 232(3):395-405; Literature 2, Dittmayer C, Goebel HH, Heppner FL, etal. Preparation of Samples for Large-Scale Automated Electron Microscopy of Tissue and Cell Ultrastructure[J].Microscopy and Microanalysis, 2021 27(4):815-827; Document 3, Zhang HW, Zhao YM, Wang YH, et al. On the microstructuralevolution pattern toward nano-scale of an AISI 304stainless steel during highstrain rate surface deformation[J]. Journal of Materials Science&Technology, 2020 44:148-159; Document 4, Yoreo JD, Gilbert PU, Sommerdijk NA,etal.Crystallization by particle attachment in synthetic,biogenic,and geologicenvironments[J].Science,2015 349(6247):498-508; Document 5, Zuo PL, Lu XH, SunZ G,etal.A review on syntheses,properties,characterization and bioanalyticalapplications of fluorescent carbon dots[J]. Microchim Acta, 2016 183(2):519-542; Document 6, Lee HC, Liu WW, Chai SP, et al. Review of the synthesis, transfer, characterization and growth mechanisms of single and multilayer graphene[J]. RSC Advances, 2017 7(26):15644–15693).

[0005] At present, the transfer and preparation of transmission electron microscopy samples of nanomaterials located on a substrate often requires the use of organic polymers (such as PMMA, rosin, polypropylene carbonate, ion gel, paraffin, etc.) as auxiliary media. However, this method is relatively complicated and requires two high-temperature curing steps, which may affect the structure of the nanomaterials. Moreover, organic polymers are often difficult to remove completely, which has a great impact on sample characterization. (See references: Reference 7, Zhang F, Hou PX, Liu C, et al. Growth of semiconducting single-wall carbon nanotubes with a narrow band-gap distribution [J]. Nature Communications, 2016 7: 11160; Reference 8, Ma LP, Wu ZB, Yin LC, et al. Pushing the conductance and transparency limit of monolayer graphene electrodes for flexible organic light-emitting diodes [J]. PNAS, 2020 117 (42): 25991–25998)

[0006] Therefore, the main problem currently faced is: how to achieve lossless and clean transfer of nanomaterials grown on substrates in order to obtain high-quality transmission electron microscopy samples. Summary of the invention

[0007] The purpose of the present invention is to provide a method for preparing nanomaterial transmission electron microscope samples by using single-walled carbon nanotube film transfer, which can simply and quickly prepare nanomaterial transmission electron microscope samples by using high-transmittance single-walled carbon nanotube film transfer, simplify the preparation process of nanoparticles grown on a substrate and two-dimensional material transmission samples, and obtain pollution-free transmission electron microscope samples with good structural integrity. Thus, the technical problems of the existing polymer-assisted transfer method, such as complex process, high-temperature treatment destroying the structure of nanomaterials, and residual transfer medium, are overcome.

[0008] The technical solution of the present invention is:

[0009] A method for preparing a nanomaterial transmission electron microscope sample by transferring a single-walled carbon nanotube film, utilizing the van der Waals force between the single-walled carbon nanotube film and the nanomaterial and the self-supporting property of the single-walled carbon nanotube film to transfer the nanomaterial on a substrate to prepare the transmission electron microscope sample, specifically: firstly, a single-walled carbon nanotube film with high purity, high transmittance and low catalyst residue prepared by a floating catalyst chemical vapor deposition method is cut into a suitable size and pressed onto the nanomaterial located on the substrate; then, the substrate is wetted with alcohol and etched in a substrate etching solution, and the single-walled carbon nanotube film and the nanomaterial are combined with the van der Waals force to form a composite film; then, the composite film is transferred to clean water for cleaning, and the composite film is picked up using a carrier net or a support ring, and alcohol is dripped on the film for cleaning again and air-dried to obtain the transmission electron microscope sample of the nanomaterial.

[0010] The method for preparing nanomaterial transmission electron microscope samples by transferring single-walled carbon nanotube films, wherein the single-walled carbon nanotube films are grown by floating catalyst chemical vapor deposition method and directly collected on a microporous filter membrane, the bundle size distribution range of the single-walled carbon nanotubes is 2 to 10 nm, the pore size distribution range of the single-walled carbon nanotubes is 5 to 500 nm, and the Raman spectrum I G / I D Above 100, the transmittance ranges from 95% to 98%, and the catalyst residue is less than 3wt.%.

[0011] The method for preparing nanomaterial transmission electron microscope samples by transferring single-walled carbon nanotube films first utilizes the van der Waals force between the single-walled carbon nanotubes and the nanomaterials to tightly bind the two; then etches the substrate to obtain a composite film of the single-walled carbon nanotubes and the nanomaterials; then utilizes the support of the single-walled carbon nanotube film network to transfer the composite film to prepare a transmission electron microscope sample; finally utilizes the ultra-high light transmittance of the single-walled carbon nanotube film to allow the electron beam to pass through for high-definition observation.

[0012] The method for preparing nanomaterial transmission electron microscope samples by transferring single-walled carbon nanotube films is as follows: using a glass slide or a quartz plate, the composite film is picked up from bottom to top, and after being transferred to clean water, the composite film is floated on the water surface by utilizing the difference between the hydrophilicity of the glass slide or the quartz plate and the hydrophobicity of the single-walled carbon nanotube film.

[0013] The method for preparing a nanomaterial transmission electron microscope sample by transferring a single-walled carbon nanotube film uses a Φ3mm carrier grid or support ring and utilizes the self-supporting characteristics of the single-walled carbon nanotube film to directly fish out the composite film from clean water and dry it to obtain the transmission electron microscope sample of the nanomaterial.

[0014] The method for preparing nanomaterial transmission electron microscope samples by transferring single-walled carbon nanotube films transfers nanoparticles grown on a substrate, or transfers two-dimensional materials grown on a substrate.

[0015] In the method for preparing nanomaterial transmission electron microscope samples by transferring single-walled carbon nanotube films, nanoparticles or two-dimensional materials are not limited by material and size. The minimum size of nanoparticles is 1-2nm, and the thinnest size of two-dimensional materials is 0.3-0.4nm.

[0016] The method for preparing nanomaterial transmission electron microscope samples by transferring single-walled carbon nanotube films provides a complete and clean structure of the transferred nanoparticles or two-dimensional materials, which is conducive to transmission electron microscope characterization of their intrinsic morphology or structure.

[0017] In the method for preparing nanomaterial TEM samples by transferring single-walled carbon nanotube films, the TEM samples are not prepared on conventional microgrids with carbon films, but the nanomaterial / single-walled carbon nanotube films are directly supported on a carrier grid or a support ring.

[0018] In the method for preparing nanomaterial transmission electron microscope samples by transferring single-walled carbon nanotube films, the type of etching solution is determined by the material of the substrate.

[0019] The design concept of the present invention is:

[0020] The present invention provides a method for preparing transmission electron microscope samples of nanoparticles or two-dimensional materials grown on a substrate in a simple, clean and rapid manner. A single-walled carbon nanotube film prepared by a floating catalyst chemical vapor deposition method is combined with the van der Waals force of a nanomaterial to form a composite film. The self-supporting and hydrophobic properties of the single-walled carbon nanotube film are utilized to enable the composite film to maintain the macroscopic and microscopic structures of the film in a substrate etching solution and a clear water liquid. The high light transmittance of the single-walled carbon nanotube film (due to the pore structure of the overlapped tubes and the size of the small tube bundle) is utilized to ensure that the observed nanomaterial is "transparent" to the electron beam, thereby achieving efficient characterization of the fine structure of the nanomaterial.

[0021] The advantages and beneficial effects of the present invention are:

[0022] 1. The present invention utilizes the van der Waals force between the single-walled carbon nanotube film and the nanomaterial and the self-supporting characteristics of the single-walled carbon nanotube film to transfer the nanomaterial that is difficult to transfer cleanly on the substrate to prepare a transmission electron microscope sample. The single-walled carbon nanotube film used has high purity (metal catalyst content <3wt.%), small tube bundle size, simple chemical composition, and large inter-tube gaps, which can achieve quantitative and qualitative characterization of the morphology, structure, and fine components of the nanomaterial.

[0023] 2. The present invention introduces almost no chemical pollution, does not require heating and curing, avoids the damage of high temperature to the structure of nanomaterials, and effectively maintains the real structure of nanomaterials.

[0024] 3. The single-walled carbon nanotube film used in the present invention has good flexibility, self-support and chemical stability. The large specific surface area ensures the effective adsorption and support of nanomaterials, and plays the role of transfer carrier and support carrier at the same time. No additional carbon support film is required, which reduces the preparation cost to a certain extent.

[0025] 4. The preparation process of the present invention is simple, does not require complex equipment, has a wide range of applications, and has strong universality.

[0026] 5. The present invention solves the problem of the difficulty in cleanly and losslessly transferring nanoparticles or two-dimensional materials on a substrate to prepare transmission samples, avoids the high-temperature heating process and organic polymer residues in the traditional use of organic polymers to transfer nanomaterials, and the prepared transmission electron microscope samples are easier to characterize. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 . Flowchart of the method for preparing nanomaterial transmission electron microscopy samples by transferring single-walled carbon nanotube films.

[0028] Figure 2 .Optical photograph of single-walled carbon nanotube film collected directly on a microporous filter membrane.

[0029] Figure 3 . (a) SEM photo, (b) TEM photo and (c) Raman spectrum of single-walled carbon nanotube film; in (c), the horizontal axis Raman shift represents the Raman shift (cm -1 ), the ordinate Intensity represents the intensity of the Raman peak (au).

[0030] Figure 4 .Scanning electron microscope image of gold (Au) particles on a silicon substrate.

[0031] Figure 5.Optical photograph of transmission electron microscope sample.

[0032] Figure 6 .(a) Transmission electron microscope photo, (b) electron energy spectrum scanning photo under transmission electron microscope and (c) high-resolution transmission electron microscope photo of gold (Au) nanoparticle sample prepared by transfer of single-walled carbon nanotube film.

[0033] Figure 7 .Transmission electron microscope photo of graphene sample prepared by single-walled carbon nanotube film transfer.

[0034] Figure 8 . Transmission electron microscopy image of gold (Au) nanoparticle sample assisted by polymethyl methacrylate (PMMA). DETAILED DESCRIPTION

[0035] like Figure 1 As shown in the figure, the method of preparing nanomaterial transmission electron microscope samples by transferring single-walled carbon nanotube films is divided into the following steps: (1) growing single-walled carbon nanotubes with high purity, low catalyst residue and high transmittance by floating catalyst chemical vapor deposition, and directly depositing them on a microporous filter membrane to obtain a single-walled carbon nanotube film with high flexibility, high mechanical strength and high transmittance, and then cutting the filter membrane into a suitable size; (2) placing the cut filter membrane loaded with single-walled carbon nanotubes on a substrate on which nanomaterials are grown, so that the single-walled carbon nanotube film is in close contact with the nanomaterial, and utilizing the strong interaction between the single-walled carbon nanotube film, the nanomaterial and the silicon substrate to form a nanomaterial. According to the characteristics of the interaction force between the single-walled carbon nanotube film and the microporous filter membrane, the microporous filter membrane is peeled off with tweezers, and then it is moistened with alcohol to improve the bonding force; (3) the substrate carrying the single-walled carbon nanotube film is placed in a suitable etching solution to etch the substrate, and the single-walled carbon nanotube film and the nanomaterial are combined through van der Waals force to form a composite film; (4) after the etching of the substrate is completed, the carbon nanotube film carrying the nanomaterial is transferred to clean water for cleaning with a clean quartz sheet or glass slide, and then it is fished out with a Φ3mm carrier mesh (or support ring); (5) a few drops of alcohol are applied, and the sample is cleaned again and dried to obtain a transmission electron microscope sample of the nanomaterial.

[0036] In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention is described in detail below through embodiments and drawings, but this is not intended to limit the scope of protection of the present application.

[0037] Example 1

[0038] (1) Under optimized floating catalyst chemical vapor deposition conditions (the previous invention of this research group, patent publication number: CN110155986A), high-purity, small-bundle single-walled carbon nanotubes are grown. For specific process parameters, please refer to Example 1 of the patent: Under the protection of 1000sccm of argon, the temperature of the reactor is first raised to 1100°C, and then 6500sccm of carrier gas hydrogen and 11sccm of gaseous carbon source ethylene are introduced. A mixed solution of liquid carbon source toluene, catalyst precursor ferrocene and growth promoter thiophene (mass ratio of 10:0.3:0.045) is injected into the reactor at a rate of 0.1 ml / hour using a syringe. The single-walled carbon nanotubes grown in the reactor form a single-walled carbon nanotube film on the porous filter membrane at the lower end of the reactor.

[0039] The single-walled carbon nanotubes were deposited on a microporous filter membrane (in this embodiment, a water-based microporous filter membrane was used, the filter membrane thickness was 0.1 mm, the pore size was 0.45 μm, and the microporosity was 8%). By adjusting the collection time, the light transmittance of the single-walled carbon nanotube film was about 95%. The microporous filter membrane deposited with the single-walled carbon nanotubes was cut into blocks of 3×3 mm in size. Figure 2 and Figure 3 As shown in FIG. 1 , the characteristics of the single-walled carbon nanotube film are as follows: the purity of the single-walled carbon nanotube film is high, there is almost no catalyst residue, the tube bundle diameter distribution is 2nm to 10nm, and the laser Raman spectroscopy characterization shows that the single-walled carbon nanotube film has a high crystallinity (I G / I D Up to 100 or more).

[0040] (2) Gold nanoparticles were prepared by magnetron sputtering on an N-type silicon wafer (resistivity 0.05-0.2Ω·cm, with a 300nm thick silicon oxide layer) with an area of ​​3mm×3mm and a thickness of 400μm. The size of the nanoparticles was 1-5nm. The deposition temperature was 400℃; the deposition power was 50W; the argon pressure was 10 -2 ~10 -3 Pa; deposition time: 10s. Figure 4 As shown in the SEM morphology of the gold particles after deposition, Figure 4 It can be seen that the gold nanoparticles are evenly distributed on the substrate and the size is about a few nanometers.

[0041] (3) The single-walled carbon nanotube film with a transmittance of 95% cut in step (1) is placed on the upper surface of the substrate prepared in step 2, so that the single-walled carbon nanotube film is in close contact with the substrate and the nanomaterials thereon, the microporous filter membrane is removed, and the single-walled carbon nanotube film is wetted with anhydrous ethanol.

[0042] (4) The silicon substrate loaded with the single-walled carbon nanotube film / gold nanoparticles is placed in a 5 wt % HF aqueous solution and the substrate is etched at room temperature.

[0043] (5) Use a clean glass slide to transfer the composite film after etching the substrate into clean water for cleaning, then use a Φ3mm molybdenum grid (150 mesh) to pick up the film, apply alcohol, clean it again, and then dry it to obtain the transmission electron microscope sample. Figure 5 As shown in the optical photograph of the obtained transmission sample, it can be seen that the carbon nanotube film is uniformly supported on the molybdenum grid. Figure 6 As shown in the transmission electron microscope photo and electron energy spectrum scan of gold nanoparticles, the gold particles are evenly distributed, the structure is clearly visible, and there is no pollution; the energy spectrum scan only shows Au and C elements, indicating that the chemical composition of the sample is not contaminated by the sample preparation process.

[0044] Example 2

[0045] (1) The same as step (1) in Example 1, the light transmittance of the single-walled carbon nanotube film was 96%.

[0046] (2) A two-dimensional graphene material is grown on pure copper foil using chemical vapor deposition. The thickness of the graphene is 0.35 nm. The copper substrate on which the graphene is grown is cut into small pieces of about 3 mm × 3 mm.

[0047] (3) Same as step (3) in Example 1.

[0048] (4) Placing the copper substrate loaded with the single-walled carbon nanotube film / graphene in a copper etching solution to etch the substrate, wherein the composition and content of the copper etching solution are as follows: 80-85% ferric chloride and 15-20% concentrated hydrochloric acid by weight percentage.

[0049] (5) Same as step (5) in Example 1. Figure 7 As shown in the photo of the prepared graphene transmission electron microscope sample, the graphene is flat, clean and pollution-free.

[0050] Example 3

[0051] (1) The same as step (1) in Example 1, the light transmittance of the single-walled carbon nanotube film is 98%.

[0052] (2) Silver nanoparticles were prepared by magnetron sputtering on an N-type silicon wafer (resistivity 0.05-0.2Ω·cm, with a 300nm thick silicon oxide layer) with an area of ​​3mm×3mm and a thickness of 400μm. The size of the nanoparticles was 1-10nm. The deposition temperature was 25°C; the deposition power was 50W; the argon pressure was 10 -2 ~10 -3 Pa; deposition time: 10s.

[0053] (3) Same as step (3) in Example 1.

[0054] (4) The silicon substrate loaded with single-walled carbon nanotubes / silver nanoparticles prepared in step 3 is placed in a KOH aqueous solution (the concentration of the KOH solution used in this example is 3.6 mol / L) to etch the substrate.

[0055] (5) Same as step (5) in Example 1. Typical transmission electron microscope photos of the prepared Ag particle transmission sample show that the Ag particles are evenly distributed, the structure is clearly visible, and there is no pollution.

[0056] Comparative Example

[0057] (1) Same as step (2) in Example 1.

[0058] (2) Spin-coat the PMMA solution onto the silicon substrate prepared in step 1 (the concentration of the PMMA solution used in this comparative example is 4%).

[0059] (3) The silicon substrate spin-coated with PMMA was placed in a furnace at 150° C. for curing for 30 min.

[0060] (4) Same as step (4) in Example 3.

[0061] (5) The PMMA film was fished out using a Φ3 mm carbon support film and cured again in a furnace at 150 °C for 30 min.

[0062] (6) Soak the solidified carbon support film in hot acetone until the PMMA is removed, take out the carbon support film, apply alcohol to clean it, and dry it to obtain a transmission electron microscopy sample of gold nanoparticles. Figure 8 As shown in the transmission electron microscope photo of typical gold nanoparticles, the gold particles are obviously agglomerated and there are a lot of PMMA residues, which obviously interferes with the characterization of the sample.

[0063] The results of the embodiments and comparative examples show that the present invention can prepare transmission electron microscope samples of nanomaterials grown on a substrate by using single-walled carbon nanotube film-assisted transfer. The transfer process is simple, efficient, and does not introduce pollutants. The transferred nanomaterials retain the original morphology and intrinsic structure of the original materials. The problems of complex preparation process, introduction of polymer pollutants, and damage to the structure of nanomaterials in polymer-assisted transfer are effectively avoided. This is of great significance for promoting basic research such as structural characterization and mechanism exploration of nanomaterials, as well as related application exploration.

Claims

1. A method for preparing nanomaterial transmission electron microscope samples by using single-walled carbon nanotube film transfer, characterized in that: The nanomaterials on the substrate are transferred to prepare transmission electron microscope samples by utilizing the van der Waals force between the single-walled carbon nanotube film and the nanomaterial and the self-supporting characteristics of the single-walled carbon nanotube film. Specifically, the single-walled carbon nanotube film with high purity, high transmittance and low catalyst residue prepared by the floating catalyst chemical vapor deposition method is cut into a suitable size and pressed onto the nanomaterial located on the substrate; then, the substrate is wetted with alcohol and etched in a substrate etching solution, and the single-walled carbon nanotube film and the nanomaterial are combined with the van der Waals force to form a composite film; then, the composite film is transferred to clean water for cleaning, and the composite film is picked up using a carrier mesh or a support ring, and alcohol is dripped on the film for cleaning again and dried to obtain a transmission electron microscope sample of the nanomaterial.

2. The method for preparing nanomaterial transmission electron microscope samples by using single-walled carbon nanotube film transfer according to claim 1, characterized in that: The single-walled carbon nanotube film used was grown by floating catalyst chemical vapor deposition and directly collected on a microporous filter membrane. The bundle size distribution range of the single-walled carbon nanotubes was 2 to 10 nm, the pore size distribution range was 5 to 500 nm, and the Raman spectrum I G / I D Above 100, the transmittance ranges from 95% to 98%, and the catalyst residue is less than 3wt.%.

3. The method for preparing nanomaterial transmission electron microscope samples by using single-walled carbon nanotube film transfer according to claim 1, characterized in that: First, the van der Waals force between the single-walled carbon nanotubes and the nanomaterials is used to tightly bind the two together; then the substrate is etched to obtain a composite film of the single-walled carbon nanotubes and the nanomaterials; Then, utilizing the supportive properties of the single-walled carbon nanotube film network, the composite film was transferred to prepare a transmission electron microscope sample; finally, the ultra-high light transmittance of the single-walled carbon nanotube film was utilized to allow the electron beam to pass through for high-definition observation.

4. The method for preparing nanomaterial transmission electron microscope samples by using single-walled carbon nanotube film transfer according to claim 1, characterized in that: The method for transferring the composite film between the etching solution and the clean water is as follows: use a glass slide or a quartz plate to pick up the composite film from the bottom to the top, transfer it to the clean water, and then use the difference between the hydrophilicity of the glass slide or the quartz plate and the hydrophobicity of the single-walled carbon nanotube film to make the composite film float on the water surface.

5. The method for preparing nanomaterial transmission electron microscope samples by using single-walled carbon nanotube film transfer according to claim 1, characterized in that: Using a Φ3mm grid or support ring and utilizing the self-supporting characteristics of the single-walled carbon nanotube film, the composite film is directly fished out from the clean water and air-dried to obtain a transmission electron microscope sample of the nanomaterial.

6. The method for preparing nanomaterial transmission electron microscope samples by using single-walled carbon nanotube film transfer according to claim 1, characterized in that: The method transfers nanoparticles grown on a substrate, or transfers two-dimensional materials grown on a substrate.

7. The method for preparing nanomaterial transmission electron microscope samples by using single-walled carbon nanotube film transfer according to claim 6, characterized in that: Nanoparticles or two-dimensional materials are not limited by material and size. The minimum size of nanoparticles is 1 to 2 nm, and the thinnest size of two-dimensional materials is 0.3 to 0.4 nm.

8. The method for preparing nanomaterial transmission electron microscope samples by using single-walled carbon nanotube film transfer according to claim 6, characterized in that: The transferred nanoparticles or two-dimensional materials have a complete and clean structure, which is conducive to the transmission electron microscopy characterization of their intrinsic morphology or structure.

9. The method for preparing nanomaterial transmission electron microscope samples by using single-walled carbon nanotube film transfer according to claim 1, characterized in that: The TEM samples are not prepared on conventional microgrids with carbon films, but the nanomaterials / single-walled carbon nanotube films are directly supported on the grid or support ring.

10. The method for preparing nanomaterial transmission electron microscope samples by using single-walled carbon nanotube film transfer according to claim 1 or 4, characterized in that: The type of etching solution is determined by the material of the substrate.

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