Method for rapidly and controllably preparing single-diameter carbon nanotube
By physically deposition of transition metals and carbon on a single-wall carbon nanotube network and using rapid heating to form ultrafine nanowires as catalysts, the rapid, controllable and efficient preparation of single-diameter carbon nanotubes is achieved, and the problem of difficulty in controlling the diameter of carbon nanotubes in the prior art is solved and its application prospects are broadened.
Patent Information
- Application Number
- CN202510075481.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-17
- Publication Date
- 2025-05-16
Smart Images
Figure CN120004254A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the field of controllable preparation of nano carbon materials, in particular to a method for rapidly and controllably preparing single-diameter carbon nanotubes. Background Art
[0002] Carbon nanotubes can be regarded as one-dimensional hollow tubular structures formed by curling graphene, in which the radial size of the hollow tube cavity is nanometer scale. The diameter of carbon nanotubes prepared by general methods is 0.6-100nm, among which the diameter of single-walled carbon nanotubes is 0.6-3.0nm, and the diameter of multi-walled carbon nanotubes is 5.0-100nm. The band gap of semiconducting single-walled carbon nanotubes is inversely proportional to the diameter. Semiconducting single-walled carbon nanotubes with the same band gap are ideal channel materials for field effect transistors. Multi-walled carbon nanotubes with different diameters can realize the screening and storage of molecules of different sizes, and are one of the ideal carriers for transporting drugs. However, there are few reports on the application of single-diameter carbon nanotubes, mainly because it is difficult to obtain carbon nanotubes with a single diameter.
[0003] It is very difficult to control the diameter of carbon nanotubes. This is mainly because carbon nanotubes usually grow under high temperature conditions using catalyst nanoparticles as "seeds" and "templates". There are still many unresolved problems in this process: (1) It is difficult to prepare catalyst nanoparticles of uniform size; (2) Catalyst nanoparticles tend to agglomerate and grow at high temperatures, further increasing the size difference; (3) There are two modes when carbon nanotubes nucleate from nanoparticles of uniform size, one is the "vertical mode" in which the diameter of the carbon nanotube is much smaller than the diameter of the nanoparticle, and the other is the "tangential mode" in which the diameter of the carbon nanotube is similar to the diameter of the nanoparticle. Currently, there is no method to make carbon nanotubes nucleate in a single mode; (4) During long-term high-temperature chemical vapor deposition, the temperature and the decomposition of the gaseous carbon source interfere with each other, making it difficult to provide equilibrium conditions for the nucleation and growth of carbon nanotubes.
[0004] Based on the above problems, researchers have developed a variety of methods to control the diameter of carbon nanotubes:
[0005] (1) Synthesis of catalyst nanoparticles with controllable size. The synthesis of catalyst precursors with uniform and controllable size is the prerequisite for obtaining uniform catalyst nanoparticles and then achieving controllable growth of carbon nanotubes. Researchers have developed a series of methods, such as using organic molecules to control the size of metal catalyst precursors. Dai et al. prepared Fe2O3 nanoparticles with uniform and adjustable size by controlling the amount of Fe ions filled into hollow apoferritin, and then grew carbon nanotubes with controllable diameter (Reference 1: J.Phys.Chem.B 2001,105(46),11424-11431); Liu et al. used octanoic acid and diisooctylamine as protective agents, and synthesized Fe-Mo nanoparticles with narrow diameter distribution in dioctyl ether through thermal cracking reaction of metal carbonyl complexes, and used this as a catalyst to grow carbon nanotubes with controllable diameter (Reference 2: Chem.Mat.2001,13(3),1008-1014). However, the diameter distribution of carbon nanotubes prepared by regulating the size of catalyst nanoparticles is still relatively wide, and its controllability needs to be improved.
[0006] (2) Optimize the chemical vapor deposition process. The nucleation mode is controlled by adjusting the reaction conditions such as the composition, concentration, and growth temperature of the carbon source gas in the chemical vapor deposition method to achieve controllable growth. For example, when CO is used as the carbon source, carbon nanotubes tend to adopt a vertical growth mode; when the carbon source is changed to CH4, carbon nanotubes tend to grow in a tangential mode (Reference 3: Nanoscale 2018, 10 (14), 6744-6750). The use of different carbon sources can regulate the nucleation mode of carbon nanotubes, but the lack of catalyst nanoparticles with uniform diameters means that the diameter range of carbon nanotubes grown by this method is still relatively wide.
[0007] (3) Designing catalysts with special structures. Zhang et al. used a block copolymer self-assembly method to prepare a monodisperse, uniformly sized partially carbon-coated Co catalyst nanoparticle, and controlled the nucleation and growth of carbon nanotubes from uncoated Co nanoparticles in a "vertical mode" to form semiconductor carbon nanotubes with narrow chirality distribution (Reference 4: Nat. Commun. 2016, 7(1), 11160). This achieved the controllable growth of carbon nanotubes with narrow diameter distribution, but the "vertical mode" can only ensure that the diameter of the carbon nanotube is smaller than the catalyst nanoparticle "template", and its controllability still needs to be further improved.
[0008] In summary, single-diameter carbon nanotubes have broad application prospects, but to achieve their controllable preparation, the following problems need to be solved urgently: (1) Obtain a high-temperature stable, uniform-sized catalyst nanoparticle "template". (2) Make the catalyst nanoparticles nucleate and grow carbon nanotubes of the same size as the catalyst in a "tangential mode". (3) Shorten the high-temperature heating time to ensure the uniformity of the size of the catalyst nanoparticles. Summary of the invention
[0009] The present invention aims to provide a method for rapidly and controllably preparing single-diameter carbon nanotubes, by rapidly heating the metal and carbon supported on the single-walled carbon nanotube network to induce the formation of ultrafine nanowires with carbon nanotube bundles, and rapidly raising and lowering the temperature to allow the nanowires to nucleate and grow single-diameter carbon nanotubes in a "tangential mode".
[0010] The technical solution of the present invention:
[0011] A method for rapidly and controllably preparing single-diameter carbon nanotubes comprises the following steps: using a physical deposition method to controllably deposit transition metals and carbon on a single-wall carbon nanotube network, rapidly heating at a heating rate of 50 to 1500°C / s to form ultrafine nanowires from metal nanoparticles on the single-wall carbon nanotubes, then using the physically deposited carbon as a solid carbon source, rapidly heating to a high temperature of 1000 to 2500°C at a rate of 50 to 1500°C / s, and then cooling at a rate of 50 to 1500°C / s to use the ultrafine metal nanowires as catalysts to nucleate and grow single-diameter carbon nanotubes having the same radial size as the single-wall carbon nanotubes in a tangential mode.
[0012] The method for rapidly and controllably preparing carbon nanotubes with a single diameter controls the process parameters in physical deposition and adjusts the heating rate and the maximum heating temperature in the rapid heating process to control the diameter of the ultrafine metal nanowires and the diameter and the number of tube walls of the grown carbon nanotubes, thereby obtaining carbon nanotubes with different diameters. By adjusting the heating rate, the maximum temperature, and the interaction between the transition metal and carbon during rapid heating, the diameter of the carbon nanotubes can be adjusted within the range of 2 to 15 nm and the number of tube walls can be adjusted within the range of 1 to 20 layers.
[0013] The method for rapidly and controllably preparing carbon nanotubes with a single diameter controls the radial size of ultrafine metal nanowires by regulating the deposition amount of transition metals during physical deposition and the maximum temperature of rapid heating, thereby achieving an adjustable diameter of the carbon nanotubes within a range of 2 to 15 nm; wherein the process parameters for controlling the deposition amount of transition metals during physical deposition are: deposition power of 2 to 50 W and deposition time of 50 to 500 s.
[0014] The method for rapidly and controllably preparing carbon nanotubes with a single diameter comprises a physical deposition method of ion beam sputtering, magnetron sputtering or thermal evaporation, a physically deposited transition metal that cannot form a stable compound with carbon and has a high melting point, and a transition metal of Ru, Rh, Nb, Mo, W, Re or Ta, which forms ultrafine metal nanowires under the induction effect of inter-tube confinement of carbon nanotubes, and whose diameter is 2 to 15 nm and aspect ratio is 1.5 to 10.
[0015] The method for rapidly and controllably preparing single-diameter carbon nanotubes can adjust the number of tube walls of the grown carbon nanotubes within a range of 1 to 20 layers by selecting transition metals with different carbon solubility, adjusting the carbon deposition amount and the rapid heating rate; wherein the process parameters for adjusting the carbon deposition amount are: deposition power of 5 to 60 W and deposition time of 200 to 5000 s.
[0016] The method for rapidly and controllably preparing single-diameter carbon nanotubes uses a high-quality single-walled carbon nanotube network. G / I D >120) single-walled carbon nanotube networks that induce metals to form ultrafine nanowires that can maintain a self-supporting structure after deposition of transition metals and carbon and subsequent rapid high-temperature heating.
[0017] The method for rapidly and controllably preparing single-diameter carbon nanotubes can achieve rapid preparation of single-diameter carbon nanotubes with controllable tube wall number and diameter within 1 to 10 seconds. The growth time of the carbon nanotubes is 1 to 10 seconds, and the aspect ratio is between 3 and 10. 3 Range-tunable carbon nanotubes.
[0018] The method for rapidly and controllably preparing carbon nanotubes of a single diameter uses different metals as catalysts and achieves controllable preparation of single-walled carbon nanotubes of a single diameter by regulating the amount of deposited metal, rapid heating and cooling rates, and maximum heating temperature. On this basis, the structural uniformity of the single-diameter carbon nanotubes is further improved by combining vapor phase etching to selectively grow single-walled carbon nanotubes of a single conductive property / chirality.
[0019] The method for rapidly and controllably preparing single-diameter carbon nanotubes comprises introducing an etching gas with suitable chemical reactivity, including NH3, CO2, NO2, H2O or SO3, by vapor phase etching to selectively remove metallic carbon nanotubes with high chemical reactivity, thereby obtaining semiconductor single-walled carbon nanotubes with a single band gap or single-chirality single-walled carbon nanotubes.
[0020] The design idea of the present invention is:
[0021] The present invention uses single-walled carbon nanotube bundles as a "template" to induce the formation of ultrafine nanowires, and uses the nanowires as template catalysts to nucleate and grow carbon nanotubes with radial dimensions consistent with the nanowires according to a determined "tangent mode"; a metal that has a suitable interaction with carbon is selected as a catalyst, and "carbon melts and carbon precipitates" during the rapid heating and cooling process to achieve rapid, efficient and controllable growth of carbon nanotubes.
[0022] A certain amount of transition metals (Ru, Rh, Nb, Mo, W, Re, Ta) and carbon are deposited on a high-quality single-walled carbon nanotube network by physical deposition methods such as ion beam sputtering, magnetron sputtering, and thermal evaporation; the metal nanoparticles are rapidly heated (heating rate 50-1500℃ / s) to form ultrafine nanowires (diameter 2-10nm) on the carbon nanotube bundle, and the metal nanowires are used as catalysts to grow carbon nanotubes with the same diameter along the tangent direction. In this method, the amount of metal and carbon deposition is regulated by regulating the power and deposition time of physical deposition, and the heating rate and the maximum heating temperature during the rapid heating process are combined to achieve the regulation of the diameter of the ultrafine metal nanowires and the diameter and number of walls of the grown carbon nanotubes, and obtain carbon nanotubes of different diameters. This method can complete the rapid, controllable, and efficient preparation of single-diameter carbon nanotubes within 1-10s, and can be combined with selective etching to prepare single-walled carbon nanotubes with single conductive properties / chirality.
[0023] The advantages and beneficial effects of the present invention are:
[0024] 1. The present invention provides a method for preparing single-diameter carbon nanotubes, which controls the ultra-fine nanowires to nucleate and grow single-diameter carbon nanotubes with uniform radial dimensions in a "tangent mode".
[0025] 2. The present invention provides a method for preparing ultrafine metal nanowires, which rapidly heats metal nanoparticles deposited on carbon nanotube bundles to form ultrafine nanowires.
[0026] 3. The present invention provides a method for rapidly preparing carbon nanotubes, which utilizes the heat generated by Joule heat to rapidly heat ultrafine nanowires to achieve "carbon dissolution-carbon precipitation", thereby completing the growth of carbon nanotubes within tens of seconds.
[0027] 4. The present invention combines methods such as vapor phase etching to further improve the structural uniformity of single-diameter carbon nanotubes and selectively grow single-walled carbon nanotubes with single conductive properties / chirality; it achieves efficient and controllable preparation of carbon nanotubes with controllable wall number and diameter within seconds, broadens the application scenarios of carbon nanotubes, and the obtained single-diameter carbon nanotubes have broad application prospects in the fields of drug delivery, nanoelectronic devices, etc. BRIEF DESCRIPTION OF THE DRAWINGS
[0028] Figure 1 . Schematic diagram of the process for rapid and controllable preparation of single-diameter carbon nanotubes.
[0029] Figure 2 .(a) Transmission electron microscopy photo and (b) Raman spectrum of single-walled carbon nanotube film (excitation wavelength: 633nm). (b) In the figure, the horizontal axis Ramanshift represents the Raman shift (cm -1 ), the vertical axis Intensity represents the relative intensity (au).
[0030] Figure 3 .Transmission electron micrograph of W nanowire / single-walled carbon nanotube composite film.
[0031] Figure 4 .Transmission electron micrograph of W2C nanowire / few-walled carbon nanotube composite film.
[0032] Figure 5 . Transmission electron micrograph of W2C nanowires and their grown few-walled carbon nanotubes.
[0033] Figure 6 .Transmission electron micrograph of Mo2C nanowire / few-walled carbon nanotube composite film.
[0034] Figure 7 . Transmission electron microscopy image of graphene film loaded with W nanoparticles. DETAILED DESCRIPTION
[0035] In the specific implementation process, the present invention proposes a method for preparing ultrafine nanowires by rapid heating and using them as catalysts to grow single-diameter carbon nanotubes, and the process is shown as follows: physical deposition methods such as ion beam sputtering, magnetron sputtering, and thermal evaporation are used to deposit transition metals and carbon on a high-quality single-walled carbon nanotube network; the power and time of the physical deposition and the type of deposited metal are regulated, and the metal is then rapidly heated to form ultrafine nanowires, and carbon nanotubes with controllable tube wall numbers and diameters are grown within seconds by adjusting the rapid heating rate and final temperature.
[0036] Below, the present invention is further described in detail by examples.
[0037] Example 1
[0038] like Figure 1 As shown, W nanowires nucleate and grow single diameter few-walled carbon nanotubes in a "tangent mode". The specific experimental steps are:
[0039] (1) Magnetron sputtering deposition of metal W
[0040] The high quality (G peak intensity I G and D peak intensity I D The ratio of I G / I D =170) Single-walled carbon nanotube film ( Figure 2 ) was placed in the chamber of the magnetron sputtering equipment and evacuated to 1.0×10 -5 Pa, heated to 300 ° C, sputtered metal W, the deposition power was 10 W, and the coating time was 175 s; then sputtered graphite to deposit carbon, the deposition power was 45 W, and the coating time was 1000 s, and W nanoparticles / single-walled carbon nanotube composite films ( Figure 3).
[0041] (2) Rapid heating of composite films of single-walled carbon nanotubes loaded with W nanoparticles
[0042] The W-deposited single-walled carbon nanotube film was placed in a rapid heating device, and rapidly heated to 2200°C (heating rate 1100°C / s) in an Ar gas (volume purity > 99.999%) atmosphere, and finally cooled to room temperature (cooling rate 1500°C / s). W nanoparticles formed ultrafine nanowires on the single-walled carbon nanotubes, with an average diameter of 6.1nm and an aspect ratio of 1.5 to 6.
[0043] (3) Structural characterization
[0044] The sample prepared in step (2) was placed in anhydrous ethanol and ultrasonically treated for 10 min. The dispersion was then dropped onto the microgrid using a pipette and dried before being observed under a transmission electron microscope. The morphology was as follows: Figure 4 As shown. It can be seen that the W2C nanowires have grown few-walled carbon nanotubes with the same diameter as the nanowires ( Figure 5 ), with an average diameter of 6.0 nm, a wall number of 3 to 10, and an aspect ratio of 3 to 10.
[0045] Example 2
[0046] In this embodiment, Mo nanowires are nucleated and grown into single diameter carbon nanotubes in a "tangential mode". The specific experimental steps are as follows:
[0047] (1) Ion beam sputtering deposition of metal Mo
[0048] High quality (I G / I D =130) The single-walled carbon nanotube film was placed in an ion beam sputtering coating machine and evacuated to a pressure of 3×10 -4 Pa, substrate temperature was 200 °C, deposition power was 20 W, and a Mona particle / single-walled carbon nanotube composite film was obtained.
[0049] (2) Rapid heating of composite films of single-walled carbon nanotubes loaded with Mo nanoparticles
[0050] The composite film was placed in a rapid heating device, 500ppmH2O was introduced in an Ar gas (volume purity>99.999%) atmosphere, and rapidly heated to 2500℃ (heating rate 1500℃ / s), and finally rapidly cooled to room temperature (cooling rate 1500℃ / s). Mo nanoparticles formed ultrafine nanowires on single-walled carbon nanotubes, with an average diameter of 5.9nm and an aspect ratio of 4-8.
[0051] (3) Structural characterization
[0052] The same as step (3) in Example 1. It can be seen that the carbon nanotubes ( Figure 6 ), with an average diameter of 8 nm, a wall number of 1 to 15, and an aspect ratio of 5 to 100. Electron diffraction analysis shows that it has a consistent electron diffraction pattern, indicating that it has a single chirality.
[0053] Example 3
[0054] In this embodiment, Nb nanowires are nucleated and grown into single-diameter double-walled carbon nanotubes in a "tangent mode". The specific experimental steps are as follows:
[0055] (1) Thermal evaporation deposition of metal Nb
[0056] High quality (I G / I D =150) single-walled carbon nanotube film was placed in a thermal evaporation coating apparatus and evacuated to 8.0×10 -4 Pa, heated to 200°C, evaporated metal Nb, the current was 1.0A, and the coating time was 200s; after the deposition, graphite was deposited, the deposition power was 50W, and the deposition time was 1200s to obtain a Nb nanoparticle / single-walled carbon nanotube composite film.
[0057] (2) Rapid heating of composite films of single-walled carbon nanotubes loaded with Nb nanoparticles
[0058] The composite film was placed in a rapid heating device, and rapidly heated to 1000°C (heating rate 50°C / s) in an Ar gas (volume purity > 99.999%) atmosphere, and finally rapidly cooled to room temperature (cooling rate 50°C / s). Nb nanoparticles formed ultrafine nanowires on single-walled carbon nanotubes, with an average diameter of 2.0nm and an aspect ratio of 1.5 to 3.
[0059] (3) Structural characterization
[0060] Similar to step (3) in Example 1, transmission electron microscopy characterization shows that the average diameter of the grown carbon nanotubes is 4.5 nm, the average number of tube walls is 2, and the aspect ratio is 100-1000.
[0061] Example 4
[0062] In this embodiment, Ru nanowires are nucleated and grown into single-diameter multi-walled carbon nanotubes in a "tangential mode". The specific experimental steps are as follows:
[0063] (1) Magnetron sputtering deposition of metal Ru
[0064] Same as step (1) in Example 1.
[0065] (2) Rapid heating of composite films of single-walled carbon nanotubes loaded with Ru nanoparticles
[0066] Different from step (2) in Example 1, after sputtering Ru and C, the film is placed in a rapid heating device, rapidly heated to 1500°C (heating rate 500°C / s) in a N2 (volume purity>99.999%) atmosphere, and finally rapidly cooled to room temperature (cooling rate 1500°C / s). Ru nanoparticles form ultrafine nanowires on single-walled carbon nanotubes, with an average diameter of 15nm and an aspect ratio of 5-10.
[0067] (3) Structural characterization
[0068] The same as step (3) in Example 1, the grown sample is a multi-walled carbon nanotube with an average diameter of 10.5 nm, a number of tube walls of 10-20, and an aspect ratio of 2-500.
[0069] Comparative Example 1
[0070] In a comparative example, metal W is deposited on a graphene support, and then carbon nanotubes are rapidly thermally grown. The specific steps are as follows:
[0071] (1) Magnetron sputtering deposition of metal W
[0072] Different from step (1) in Example 1, after the sputtering is completed, a W nanoparticle / graphene composite film is formed.
[0073] (2) Rapid heating of graphene-supported W nanoparticle composite films
[0074] Same as step (2) in Example 1.
[0075] (3) Structural characterization
[0076] The same as step (3) in Example 1, the transmission electron microscopy characterization results ( Figure 7 ) showed that W nanoparticles deposited on graphene film could not nucleate and grow carbon nanotubes after rapid heating. This shows that the single-walled carbon nanotube network is the key to the formation of ultra-fine nanowires and the growth of single-diameter carbon nanotubes in metals.
[0077] The results of the embodiments and comparative examples show that, compared with graphene film-supported metal catalysts, single-walled carbon nanotubes have a one-dimensional confined structure, which induces metals to form ultrafine nanowires during rapid heating, and the catalyst nanowire "template" nucleates and grows single-diameter carbon nanotubes in a "tangent mode". The greatest advantages of the present invention compared to the prior art are: (1) It provides a method for preparing single-diameter carbon nanotubes, controlling ultrafine nanowires to nucleate and grow single-diameter carbon nanotubes with consistent radial dimensions in a "tangent mode". (2) It provides a method for preparing ultrafine metal nanowires, which rapidly heats metal nanoparticles deposited on carbon nanotube bundles to form ultrafine nanowires. (3) It provides a method for rapidly preparing carbon nanotubes, which uses rapid heating energy to drive ultrafine nanowires to undergo "carbon dissolution-carbon precipitation", and completes the controllable preparation of single-diameter carbon nanotubes within tens of seconds.
[0078] Although the present invention has been described in detail above with general descriptions and specific embodiments, it is obvious to those skilled in the art that modifications or improvements can be made based on the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection claimed by the present invention.
Claims
1. A method for rapidly and controllably preparing carbon nanotubes of a single diameter, characterized in that: A physical deposition method is used to controllably deposit transition metals and carbon on a single-walled carbon nanotube network. Metal nanoparticles are rapidly heated at a heating rate of 50 to 1500°C / s to form ultrafine nanowires on the single-walled carbon nanotubes. The physically deposited carbon is then used as a solid carbon source and the temperature is rapidly increased to a high temperature of 1000 to 2500°C at 50 to 1500°C / s. The temperature is then lowered at 50 to 1500°C / s to allow the ultrafine metal nanowires to serve as catalysts to nucleate and grow single-diameter carbon nanotubes with the same radial size in a tangential mode.
2. A method for rapidly and controllably preparing carbon nanotubes with a single diameter according to claim 1, characterized in that: The method achieves regulation of the diameter of ultrafine metal nanowires and the diameter and number of tube walls of grown carbon nanotubes by regulating process parameters in physical deposition and combining regulation of heating rate and maximum heating temperature in the rapid heating process, thereby obtaining carbon nanotubes of different diameters. By regulating the heating rate, maximum temperature, and interaction between transition metals and carbon during rapid heating, the diameter of the carbon nanotubes can be adjusted within the range of 2 to 15 nm and the number of tube walls can be adjusted within the range of 1 to 20 layers.
3. A method for rapidly and controllably preparing carbon nanotubes with a single diameter according to claim 2, characterized in that: The radial size of the ultrafine metal nanowires is controlled by regulating the deposition amount of the transition metal during the physical deposition process and the maximum temperature of the rapid heating, so that the diameter of the carbon nanotubes can be adjusted within the range of 2 to 15 nm. The process parameters for regulating the deposition amount of the transition metal during the physical deposition process are: deposition power 2 to 50 W and deposition time 50 to 500 s.
4. A method for rapidly and controllably preparing carbon nanotubes with a single diameter according to claim 2, characterized in that: The physical deposition method is ion beam sputtering, magnetron sputtering or thermal evaporation. The physically deposited transition metal cannot form a stable compound with carbon and has a high melting point. The transition metal is Ru, Rh, Nb, Mo, W, Re or Ta. Under the induction of inter-tube confinement of carbon nanotubes, ultrafine metal nanowires are formed with a diameter of 2 to 15 nm and an aspect ratio of 1.5 to 10.
5. A method for rapidly and controllably preparing carbon nanotubes with a single diameter according to claim 2 or 4, characterized in that: By selecting transition metals with different carbon solubility, adjusting the carbon deposition amount and the rapid heating rate, the number of tube walls of the grown carbon nanotubes can be adjusted within the range of 1 to 20 layers; wherein, the process parameters for adjusting the carbon deposition amount are: deposition power 5 to 60W and deposition time 200 to 5000s.
6. A method for rapidly and controllably preparing carbon nanotubes with a single diameter according to claim 1, characterized in that: The single-walled carbon nanotube network used is of high quality (I G / I D >120) single-walled carbon nanotube networks that induce metals to form ultrafine nanowires that can maintain a self-supporting structure after deposition of transition metals and carbon and subsequent rapid high-temperature heating.
7. A method for rapidly and controllably preparing carbon nanotubes with a single diameter according to claim 1, characterized in that: The method can achieve rapid preparation of single-diameter carbon nanotubes with controllable tube wall number and diameter within 1 to 10 seconds. The growth time of the carbon nanotubes is 1 to 10 seconds, and the aspect ratio is 3 to 10. 3 Range-tunable carbon nanotubes.
8. A method for rapidly and controllably preparing carbon nanotubes with a single diameter according to claim 1, characterized in that: This method uses different metals as catalysts, and achieves controllable preparation of single-diameter single-walled carbon nanotubes by regulating the amount of deposited metal, rapid heating and cooling rates, and maximum heating temperature. On this basis, it further improves the structural uniformity of single-diameter carbon nanotubes by combining vapor phase etching, and selectively grows single-walled carbon nanotubes with a single conductive property / chirality.
9. A method for rapidly and controllably preparing carbon nanotubes with a single diameter according to claim 8, characterized in that: Vapor phase etching introduces an etching gas with suitable chemical reactivity, including NH3, CO2, NO2, H2O or SO3, to selectively remove metallic carbon nanotubes with high chemical reactivity to obtain single-bandgap semiconductor single-walled carbon nanotubes or single-chirality single-walled carbon nanotubes.