A method for processing a micro-triangle cross-section trench array graphene film

Abstract

The application discloses a processing method of a micrometer triangular cross-section trench array graphene film, and comprises the following steps: A, pre-treating a flexible sheet material to obtain a flexible sheet substrate; B, coating a carbon precursor material on the flexible sheet substrate according to the thickness of a required solid-state carbon precursor, and solidifying to obtain a flexible composite film loaded with the solid-state carbon precursor; the carbon precursor material has a triazine ring network cross-linking structure; C, adjusting laser parameters, and performing direct writing scanning on the surface of the solid-state carbon precursor by using a laser light source, and then cleaning and drying to obtain the micrometer triangular cross-section trench array graphene film. The processing method of the micrometer triangular cross-section trench array graphene film can solve the problems that the traditional processing technology cannot meet the high precision and three-dimensionalization of the graphene film micro-nano structure, the process is complex, the quality control is difficult, and the controllability is low.

Description

Technical Field

[0001] This invention relates to the field of graphene film processing, and in particular to a method for processing micron-sized triangular cross-section grooved array graphene films. Background Technology

[0002] Graphene materials possess excellent mechanical, optical, and electrochemical properties, and have significant application value in various fields such as electronics, information technology, energy, and materials.

[0003] In the field of electronic devices, as electronic devices continue to develop towards miniaturization and high performance, higher requirements are placed on the conductivity, stability and specific surface area of ​​electrode materials, and the demand for graphene films that can provide higher effective specific area and have a periodic array structure is also increasing.

[0004] Currently, graphene film preparation techniques include chemical vapor deposition, liquid phase exfoliation, and chemical reduction. However, for graphene films that need to achieve trench arraying at the micro-nano scale to obtain higher effective specific area and periodic array structure, traditional processing techniques such as chemical vapor deposition, liquid phase exfoliation, and chemical reduction produce graphene with difficult quality control, high cost, and complex processes, which cannot meet the high precision and three-dimensional requirements of graphene micro-nano structures.

[0005] Building upon the achievement of trench arraying at the micro- and nano-scale, further defining the cross-section of graphene films as triangular, with regular longitudinal channels, effectively disperses external stress, reduces stress concentration, exhibits excellent durability under cyclic loading, and maintains the high mechanical stability of graphene. Fabricating the aforementioned micron-sized triangular cross-section trench array graphene films typically requires template and photolithography methods, which are complex. Adjusting the structure necessitates the re-fabrication of the template, resulting in low controllability, difficult structural design, and complex processes. Summary of the Invention

[0006] To address the aforementioned shortcomings, the present invention aims to propose a method for processing micron-sized triangular cross-section groove array graphene films, thereby solving the problems that current traditional processing techniques cannot meet the high precision and three-dimensionality requirements of graphene film micro / nano structures, and that the processes are complex, quality control is difficult, and controllability is low.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] A method for fabricating a micron-sized triangular cross-section grooved array graphene film includes the following steps:

[0009] A. Pre-treat the flexible sheet material to obtain a flexible sheet substrate;

[0010] B. Based on the required thickness of the solid carbon precursor, the carbon precursor material is coated onto a flexible thin film substrate and cured to obtain a flexible composite film loaded with solid carbon precursor.

[0011] The carbon precursor material has a triazine ring-network cross-linked structure;

[0012] D. Adjust the laser parameters and use the laser source to perform direct writing scanning on the surface of the solid carbon precursor, then clean and dry to obtain a micron-sized triangular cross-section groove array graphene film.

[0013] Preferably, in step C, the laser parameters include a laser wavelength of 200–360 nm, a pulse width of less than 12 picoseconds, a laser power of 3–5 W, and a defocusing method for unidirectional overlapping linear laser scanning.

[0014] The spacing of the laser unidirectional overlapping linear scanning is 20-60% of the spot size, the defocusing amount is -2 to -8 mm, and the scanning speed is 80-150 mm / s.

[0015] Preferably, in step B, the carbon precursor material is one of cyanate ester resin, polytriazine polymer, and conjugated triazine polymer;

[0016] The thickness of the carbon precursor material is 60–150 μm.

[0017] Preferably, the flexible sheet material is one of polyimide, polyethylene terephthalate, polyetherimide, polyethylene naphthalate, and MXene; and the flexible sheet material is in the form of a flexible film material or a flexible paper-based material.

[0018] The thickness of the flexible sheet material is 30–150 μm.

[0019] Furthermore, when the flexible sheet material is in the form of a flexible film material, in step A, the pretreatment is a hydrophilization treatment, and the contact angle of the pretreated flexible sheet material is less than 90°;

[0020] The hydrophilization treatment is one of oxidation treatment, plasma treatment, coating with a surface activator, and laser engraving modification.

[0021] Furthermore, when the hydrophilic treatment is laser engraving modification, step A includes the following steps:

[0022] The flexible sheet material is placed at the focal point, and a laser light source is used to scribble a grid on the flexible sheet material to complete the hydrophilic treatment;

[0023] The laser source has a wavelength of 200–360 nm, a pulse width of less than 12 picoseconds, a laser power of 6–8 W, a laser scanning speed of 600–900 mm / s, and a scanning spacing of 60–100 μm.

[0024] Preferably, in step B, the operation of coating the carbon precursor material onto the flexible sheet substrate is as follows: a mask is attached to the flexible sheet substrate, the mask has an opening not smaller than the pretreatment area, the opening corresponds to the pretreatment area, and the thickness of the mask is consistent with the thickness of the desired carbon precursor.

[0025] A carbon precursor material is coated in the pretreatment area, and then the excess carbon precursor material is scraped off to control the thickness of the carbon precursor material.

[0026] The opening of the mask is processed by one of the following methods: physical cutting, photolithography, etching, and laser processing.

[0027] Preferably, when the flexible sheet material is in the form of a flexible paper-based material, the pretreatment method in step A is one of the following: impregnation, coating, and spin coating.

[0028] Furthermore, in step B, the operation of coating the carbon precursor material onto the flexible sheet substrate is as follows: the carbon precursor material is completely dissolved in a solvent to obtain a carbon precursor solution.

[0029] A carbon precursor solution is spin-coated onto a flexible sheet substrate to the required thickness using a spin coater.

[0030] Preferably, in step C, the atmosphere of the laser source is one of an air atmosphere, an inert protective gas atmosphere, an oxygen / inert gas mixture environment, and a vacuum environment.

[0031] The technical solution provided by this invention may include the following beneficial effects:

[0032] By utilizing a carbon precursor material with a triazine ring-network cross-linked structure, loaded onto a high-temperature resistant flexible sheet material, and performing direct writing scanning with specific laser parameters, graphene and corresponding micro / nano structures are formed simultaneously. This enables high-precision processing and three-dimensional fabrication of graphene films with a simple process. Furthermore, by limiting the range of laser parameters, high-quality triangular cross-section groove array graphene films can be obtained. Adjusting the parameters within this range allows for the corresponding adjustment of the micro / nano structure size, thereby regulating device performance and providing high controllability. Attached Figure Description

[0033] Figure 1 This is a SEM cross-sectional view of Embodiment 1 of the present invention.

[0034] Figure 2This is a laser confocal microscope image of Embodiment 1 of the present invention.

[0035] Figure 3 This is a SEM cross-sectional view of Comparative Example 1 of the present invention.

[0036] Figure 4 This is a laser confocal microscope image of Comparative Example 2 of the present invention.

[0037] Figure 5 These are the volt-ampere curve and potential-time curve of the capacitor obtained in Embodiment 1 of the present invention.

[0038] Figure 6 These are the current-voltage curve and potential-time curve of the capacitor obtained in Comparative Example 1 of the present invention. Detailed Implementation

[0039] The technical solution of the present invention will be further illustrated below through specific embodiments.

[0040] To facilitate understanding of the present invention, a more complete description is provided below. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the present invention.

[0041] Where specific techniques or conditions are not specified in the examples, they shall be performed in accordance with the techniques or conditions described in the literature in this field or in accordance with the product instructions. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0042] A method for fabricating a micron-sized triangular cross-section grooved array graphene film includes the following steps:

[0043] A. Pre-treat the flexible sheet material to obtain a flexible sheet substrate;

[0044] B. Based on the required thickness of the solid carbon precursor, the carbon precursor material is coated onto a flexible thin film substrate and cured to obtain a flexible composite film loaded with solid carbon precursor.

[0045] The carbon precursor material has a triazine ring-network cross-linked structure;

[0046] E. Adjust the laser parameters and use the laser source to perform direct writing scanning on the surface of the solid carbon precursor, then clean and dry to obtain a micron-sized triangular cross-section groove array graphene film.

[0047] As electronic devices continue to evolve towards miniaturization and high performance, graphene films with higher effective specific area and periodic array structures are needed to meet the demands of corresponding flexible devices. However, traditional processing techniques for graphene films are difficult to control in terms of quality, costly, and complex, failing to meet the requirements for high precision and three-dimensionality in micro / nano structures. Furthermore, when the electrical, mechanical, and chemical properties of the device change, the template needs to be remade, resulting in low controllability and high costs.

[0048] To address this, this invention proposes a method for fabricating micron-sized triangular cross-section grooved array graphene films. This method employs ultraviolet ultrafast lasers to perform direct-write scanning on a solid carbon precursor loaded on a flexible composite film, achieving the high precision and three-dimensional fabrication requirements for graphene films in micro / nano structures. Direct-write scanning using a laser source is a highly efficient, low-cost, and high-precision micro / nano fabrication technology for material synthesis and conversion. It possesses rapid processing capabilities with high efficiency and precision, broad material compatibility, and a wide processing range. Furthermore, the non-contact and high-speed nature of direct-write scanning using ultraviolet ultrafast lasers effectively avoids the complex mask preparation process in traditional photolithography. By controlling specific laser parameters, various micro / nano structures of graphene films can be efficiently fabricated, achieving three-dimensional fabrication and thus enabling macroscopic control of graphene quality.

[0049] Meanwhile, the carbon precursor material used in this invention, after curing, possesses a triazine ring-network cross-linked structure. The triazine ring-network cross-linked polymer is connected by multi-point covalent bonds, forming a high degree of cross-linking. This gives the carbon precursor with the triazine ring-network cross-linked structure excellent mechanical properties, thermal stability, and chemical resistance. After ultraviolet ultrafast laser irradiation scanning, it can effectively control the thermal diffusion of the laser irradiation area, and will not burn or expand in a large area during laser processing. This ensures high processing accuracy while being less prone to thermal deformation and surface damage. Furthermore, the high degree of cross-linking of this structure makes the surface after laser processing relatively smooth, and it can quickly maintain the formed micro-nano structure after laser removal. Furthermore, graphene can be directly synthesized on a flexible composite film loaded with the solid carbon precursor using a laser light source for direct writing scanning. The dense laser beam can generate extremely high temperatures on the target material, sufficient to break the chemical bonds of the material and cause carbon atoms to rearrange into graphene. Processing is carried out according to steps A to C, and the flexible sheet material is pretreated. The resulting flexible sheet substrate is conducive to the coating of the carbon precursor material in step B. After the carbon precursor material is coated and cured, a flexible composite film loaded with the solid carbon precursor is obtained. Under certain laser parameters, graphene can be induced to form on the surface of the solid carbon precursor while forming a regular micro-nano trench structure. The morphology and size of the micro-nano trench structure can be controlled with high precision by controlling the laser parameters. The obtained graphene has good quality and excellent conductivity, and can be used to prepare micro-advanced devices such as capacitors and sensors. This solves the problems that current traditional processing technology cannot meet the high precision and three-dimensionality of graphene film micro-nano structures, cannot control the morphology and size of micro-nano structures, and has difficulty in quality control.

[0050] Preferably, in step B, the curing conditions need to be cured according to different temperature programs based on the characteristics of various carbon precursor materials, so that the cured carbon precursor material transforms from a monomer into a highly cross-linked solid polymer and is uniformly loaded on the flexible film substrate.

[0051] Preferably, in step C, the laser parameters include a laser wavelength of 200–360 nm, a pulse width of less than 12 picoseconds, a laser power of 3–5 W, and a defocusing method for unidirectional overlapping linear laser scanning.

[0052] The spacing of the laser unidirectional overlapping linear scanning is 20-60% of the spot size, the defocusing amount is -2 to -8 mm, and the scanning speed is 80-150 mm / s.

[0053] Micrometer-scale trench array graphene films with triangular cross-sections can enhance charge transport, reduce charge accumulation and local supersaturation, improve electrochemical reactivity, and increase mechanical stability. However, this type of graphene film requires processing a solid carbon precursor using a laser source under specific laser parameters. Limiting these laser parameters ensures the full superposition and combined effect of the Gaussian effect of the laser and the Marangoni effect of the molten resin, guaranteeing the conversion of the resin into high-quality graphene while simultaneously constructing the micro-nano-scale graphene structure, resulting in a trench array graphene film with a triangular cross-section. Specifically, one factor is the Gaussian effect of lasers. The intensity distribution of a laser beam follows a Gaussian distribution, with the highest energy density in the central region and decreasing gradually with distance from the center. During linear scanning, this energy distribution causes different areas of the material surface to be heated to varying degrees. The concentrated energy in the central region leads to excessive ablation of graphene, forming a grooved array on the material surface. The lowest part of the grooves corresponds to the region with the highest laser energy. Another factor is the Marangoni effect. The Marangoni effect refers to the flow phenomenon caused by the uneven distribution of surface tension within a liquid under a temperature gradient. When a laser beam irradiates a carbon precursor material, the high energy input causes the material to rapidly heat up and transform into a high-temperature molten state. In this state, the material's fluidity increases significantly, and the Marangoni effect comes into play. Because the energy density is highest at the center of the laser beam, the molten carbon material formed in the central region flows to the lower energy sides due to the difference in surface tension. This causes the molten carbon material to stack on both sides of the laser beam path, ultimately forming a triangular micro / nano structure. Through the synergistic effect of the Gaussian and Marangoni effects of lasers, a carbonized layer is formed on the upper surface of the solid carbon precursor. The uncarbonized carbon precursor in the lower layer is also affected by the laser and flows. The upper and lower layers together form a composite micro-nano structure. That is, the laser source can prepare graphene films with fine micro-nano structures, and more specifically, it can prepare groove array graphene films with triangular cross sections.

[0054] The specified laser wavelength of 200–360 nm and pulse width of less than 12 picoseconds ensure the absorption rate of the carbon precursor material, enabling more effective absorption of laser energy and thus improving processing efficiency and quality. Simultaneously, the short pulse width of less than 12 picoseconds generates high energy density on the carbon precursor surface, guaranteeing laser processing precision and meeting the requirements of micro / nano structures. The specified laser power of 3–5 W is compatible with the performance of carbon precursors possessing a triazine ring-network cross-linked structure, preventing damage to the surface structure such as phase explosions. Within the specified scanning speed range, the corresponding laser power meets the conditions for high-quality graphene generation, satisfying quality control requirements and reducing the occurrence of insufficient coverage and poor microstructure morphology regularity. Regarding the defocusing amount, too small a defocusing amount results in an excessively small laser spot size during laser scanning, leading to highly concentrated energy and a tendency for over-ablation or over-etching. Conversely, too large a defocusing amount disperses laser energy, hindering the formation of the groove array structure. Therefore, the defocusing amount is limited to -2 to -8 mm to ensure the formation of a regular groove structure in the graphene film. Furthermore, regarding the linear scanning interval, too small an interval leads to dense laser irradiation, easily causing over-ablation. Too large an interval results in incomplete graphitization coverage, preventing the formation of the desired micro / nano structures. Therefore, the interval of the unidirectional overlapping linear laser scan is limited to 20-60% of the spot size, i.e., 16-47 μm, to ensure the cross-sectional morphology and elevation differences are within the required range, forming a regular triangular cross-section. This prevents the transformation, destruction, and disorder of the micro / nano structures, ensuring the quality of the obtained graphene film.

[0055] Preferably, the height difference of the triangular cross-section trench array structure of the graphene film is 10–50 μm, and the aspect ratio is 0.2–1.5. Exceeding this range can lead to problems such as poor graphene quality, incomplete graphene coverage, excessive ablation, and structural disorder. However, within the limited laser parameters of this invention, especially the defocusing amount, scanning spacing, and laser power, the size, spacing, and height difference of the triangular trench array can be adjusted as needed without exceeding the limits of the height difference and aspect ratio. This allows for adjustment of the electrical, mechanical, and chemical properties of the device, providing flexibility for performance optimization of energy storage devices and sensors. Specifically, under single-factor variation, the scanning spacing during laser linear overlapping scanning primarily affects the base length and height of the triangles in the cross-section. Changes in laser power represent changes in laser energy density. Fine-tuning the laser energy density can control the increase or decrease in the height difference of the trench array structure. For example, increasing the laser power increases the height difference of the trenches. This can be adjusted as needed, offering high controllability, eliminating the need to re-fabricate templates, and reducing costs.

[0056] Preferably, in step B, the carbon precursor material is one of cyanate ester resin, polytriazine polymer, and conjugated triazine polymer;

[0057] The thickness of the carbon precursor material is 60–150 μm.

[0058] Regarding the generation of graphene, different carbon precursor materials produce graphene with varying thicknesses, qualities, and generation conditions. The carbon precursor materials, after curing, possess a triazine ring-network cross-linked structure, specifically one of cyanate ester resin, polytriazine polymers, and conjugated triazine polymers. This ensures that the resulting graphene film has a regular array structure, is orderly and not easily disordered, and has good structural stability. This lays the foundation for laser processing, ensuring that the corresponding structure can be adjusted by controlling the laser parameters to obtain the desired performance.

[0059] Specifically, the thickness of the carbon precursor material is 60–150 μm to ensure the graphene structure forming effect during laser processing and to avoid excessive ablation or disorder of the micro-nano structure.

[0060] Preferably, the carbon precursor material is a cyanate ester resin. Cyanate ester resin has good thermal stability and electrical conductivity, adjustable specific surface area and pore structure, good compatibility with graphene, and good structural molding stability, which is beneficial for forming graphene films with corresponding structures.

[0061] Preferably, the flexible sheet material is one of polyimide, polyethylene terephthalate, polyetherimide, polyethylene naphthalate, and MXene; and the flexible sheet material is in the form of a flexible film material or a flexible paper-based material.

[0062] The thickness of the flexible sheet material is 30–150 μm.

[0063] Specifically, the flexible sheet material is one of polyimide, polyethylene terephthalate, polyetherimide, polyethylene naphthalate, and MXene. These flexible sheet materials all have good heat resistance, mechanical properties, and chemical stability, which is beneficial for maintaining dimensional stability during processing.

[0064] Meanwhile, the flexible sheet material serving as the substrate acts as a flexible load, without affecting the subsequent fabrication of flexible devices. The thickness of the flexible sheet material is 30-150μm, which ensures flexibility while avoiding excessive cost. It is compatible with laser scanning processing technology, will not be damaged by laser scratching, and is not prone to warping caused by thermal stress concentration.

[0065] Furthermore, when the flexible sheet material is in the form of a flexible film material, in step A, the pretreatment is a hydrophilization treatment, and the contact angle of the pretreated flexible sheet material is less than 90°;

[0066] The hydrophilization treatment is one of oxidation treatment, plasma treatment, coating with a surface activator, and laser engraving modification.

[0067] Specifically, for flexible thin film materials, the pretreatment is a hydrophilization treatment, the purpose of which is to create a hydrophilic region to facilitate the subsequent loading of carbon precursor materials. The hydrophilization treatment makes the material surface more easily wetted by water, with a contact angle of less than 90°, so that the subsequent carbon precursor materials can better wet the flexible thin film material.

[0068] In addition, the hydrophilic treatment is one of oxidation treatment, plasma treatment, coating with surface activators and laser engraving modification. While improving the hydrophilicity of the flexible film material, it will not significantly affect the mechanical properties of the flexible film material, ensuring that subsequent operations can proceed normally. At the same time, it ensures that the obtained triangular cross-section groove array graphene film has good stability and durability, which is beneficial to the subsequent fabrication of flexible electronic devices.

[0069] Furthermore, when the hydrophilic treatment is laser engraving modification, step A includes the following steps:

[0070] The flexible sheet material is placed at the focal point, and a laser light source is used to scribble a grid on the flexible sheet material to complete the hydrophilic treatment;

[0071] The laser source has a wavelength of 200–360 nm, a pulse width of less than 12 picoseconds, a laser power of 6–8 W, a laser scanning speed of 600–900 mm / s, and a scanning spacing of 60–100 μm.

[0072] Specifically, the above operations and corresponding parameters ensure the completion of the hydrophilication treatment, i.e., modification using laser. The flexible sheet material is placed at the focusing position to ensure that the laser beam patterns the image when the spot size is minimized, preventing excessive ablation. The defined laser parameters ensure that the polyimide has a sufficiently high absorption rate for the laser, effectively completing the subsequent mesh marking operation. The defined scanning spacing ensures that the marked pattern achieves the best hydrophilic effect.

[0073] Preferably, in step B, the operation of coating the carbon precursor material onto the flexible sheet substrate is as follows: a mask is attached to the flexible sheet substrate, the mask has an opening not smaller than the pretreatment area, the opening corresponds to the pretreatment area, and the thickness of the mask is consistent with the thickness of the desired carbon precursor.

[0074] A carbon precursor material is coated in the pretreatment area, and then the excess carbon precursor material is scraped off to control the thickness of the carbon precursor material.

[0075] The opening of the mask is processed by one of the following methods: physical cutting, photolithography, etching, and laser processing.

[0076] Specifically, the mask with an opening is tightly fitted to the flexible sheet substrate. The opening corresponds to the pretreatment area and is not smaller than the pretreatment area. The mask and the flexible sheet substrate together form an open micro-container, which is then filled with carbon precursor material. The thickness of the mask is 60-150 μm, which is consistent with the required thickness of the carbon precursor, thereby achieving control over its thickness.

[0077] Preferably, the length and width of the opening of the mask are both 1-3 mm larger than the pretreatment area.

[0078] Preferably, the opening shape of the mask is consistent with the pre-processing area, and can be rectangular, triangular or rhomboid.

[0079] Preferably, when the flexible sheet material is in the form of a flexible paper-based material, the pretreatment method in step A is one of the following: impregnation, coating, and spin coating.

[0080] Specifically, the flexible paper-based material itself is porous and can absorb carbon precursor materials. By using impregnation, coating or spin coating methods, a flexible paper-based material that uniformly absorbs carbon precursor materials can be obtained. This is beneficial for loading more carbon precursor materials onto its surface in the future. It prevents the paper-based material from absorbing carbon precursor materials when coating the flexible thin film substrate in step B, which would make coating difficult. It also prevents the surface structure from becoming disordered during the subsequent laser processing, which would affect the preparation of the micro-nano trench structure.

[0081] Preferably, the pretreatment is an impregnation method, using cyanate ester resin as the carbon precursor material. The cyanate ester resin is uniformly dissolved in a solvent at a volume ratio of 1:2 to obtain a carbon precursor solution. The flexible paper-based material is pretreated by immersing it in the carbon precursor solution for 10–30 minutes, ensuring at least 10 minutes to guarantee that the carbon precursor solution fully penetrates the flexible paper-based material. The carbon precursor solution used must be consistent with the carbon precursor material to be coated subsequently, meeting the material requirements of having a triazine ring-network crosslinked structure after curing. The material is then removed and dried at 50–80°C for 30–60 minutes to remove the solvent, completing the pretreatment. The solvent can be an organic solvent such as acetone, toluene, or methyl ethyl ketone (MEK), used to adjust the viscosity and flowability of the resin.

[0082] Furthermore, in step B, the operation of coating the carbon precursor material onto the flexible sheet substrate is as follows: the carbon precursor material is completely dissolved in a solvent to obtain a carbon precursor solution.

[0083] A carbon precursor solution is spin-coated onto a flexible sheet substrate to the required thickness using a spin coater.

[0084] Specifically, a solvent is selected that can effectively dissolve the carbon precursor material without reacting with it, and which can volatilize upon heating to avoid introducing other components during processing. After the pretreatment in step A, where the flexible paper-based material absorbs sufficient carbon precursor material to form a flexible sheet substrate conducive to loading, in step B, the carbon precursor needs to be loaded onto its surface using a spin coating method. The carbon precursor solution is uniformly spin-coated onto the flexible sheet substrate using a spin coater to control the thickness of the carbon precursor.

[0085] Preferably, the spin coating time is within 15s to 40s, the spin coating speed is 1500 to 4000 rpm, and the number of spin coatings is not less than 3, thereby limiting the final spin coating thickness to the range of 60 to 150 μm.

[0086] Preferably, in step C, the atmosphere of the laser source is one of an air atmosphere, an inert protective gas atmosphere, an oxygen / inert gas mixture environment, and a vacuum environment.

[0087] Specifically, a confined atmosphere can ensure that no other unrelated chemical reactions occur during the graphene generation process, and thus guarantee the quality of the graphene.

[0088] The technical solution of the present invention will be further illustrated below through specific embodiments.

[0089] Example 1

[0090] A. A polyimide film is adhered tightly to a glass substrate with dimensions of 120mm × 60mm × 3mm. The portion of the polyimide film larger than the substrate is cut off. The film is then repeatedly pressed firmly with an acrylic rod. After cleaning and drying, a 355nm, 10ps ultraviolet picosecond laser is used for grid etching, followed by hydrophilic treatment to obtain a flexible thin-film substrate. The laser etching defocusing amount is 0mm, the laser power is 8W, the scanning rate is 500mm / s, the designed grid pattern is a 50mm × 40mm rectangle, the grid spacing is 64μm, and the thickness of the polyimide film is 120μm.

[0091] B. Using a commercially available solid polyimide film as a mask, a 100mm × 40mm rectangular opening is engraved on a 120mm × 60mm polyimide film using a 355nm, 10ps ultraviolet picosecond laser. This opening is adapted to the size of the grid pattern used in step A for hydrophilic treatment. The mask and polyimide film are then pressed together and reinforced repeatedly using tweezers and a small acrylic rod. A commercially available cyanate ester resin is selected as the carbon precursor material and heated to 120°C on a heating stage. This resin is then coated onto the opening area of ​​the mask, i.e., the hydrophilic treatment area. The excess cyanate ester resin above the mask is scraped off using a coating rod, and the film is cured to obtain a flexible composite film loaded with a solid carbon precursor. The laser engraving defocus is 0mm, the laser power is 7W, and the scanning rate is 60mm / s. The mask thickness is 120μm, and the solid carbon precursor, i.e., the solid cyanate ester resin, has dimensions of 100mm × 40mm × 0.12mm.

[0092] C. Using an ultraviolet picosecond laser, the surface of the solid carbon precursor of the flexible composite film is subjected to unidirectional overlapping linear scanning in a defocused manner. Then, it is cleaned with deionized water and dried using a constant temperature heating stage. It is then peeled off from the carrier glass sheet to obtain a micron-sized triangular cross-section groove array graphene film. The laser parameters are as follows: laser wavelength is 355nm, pulse width is 10ps, laser power is 4W, defocusing amount is -2.8mm, scanning speed is 100mm / s, and the spacing of the unidirectional overlapping linear scanning is 32μm.

[0093] Comparative group

[0094] Comparative Example 1

[0095] Compared to Example 1, Comparative Example 1 directly used polyimide film as a carbon precursor.

[0096] A. Attach the polyimide film tightly to the glass sheet. The size of the carrier glass sheet is 120mm×60mm×3mm. Cut off the part of the polyimide film that is larger than the carrier glass sheet. Use an acrylic rod to repeatedly press it firmly. Then clean and dry it.

[0097] B. The surface of the solid carbon precursor of the flexible composite film is subjected to unidirectional overlapping linear scanning using an ultraviolet picosecond laser in a defocused manner. Then, it is cleaned with deionized water and dried using a constant temperature heating stage. The resulting graphene film is then peeled off from the carrier glass sheet. The laser wavelength is 355nm, the pulse width is 10ps, the laser power is 4W, the defocusing amount is -9mm, the scanning speed is 100mm / s, and the spacing of the unidirectional overlapping linear scanning is 26μm.

[0098] Comparative Example 2

[0099] Compared with Example 1, the difference in Comparative Example 2 is that, in step C, the spacing of the laser unidirectional overlapping linear scan is 82 μm.

[0100] The SEM cross-sectional image of the graphene film obtained in Example 1 is shown below. Figure 1 As shown, its image under a laser confocal microscope is as follows: Figure 2 As shown in the figure, the graphene film obtained in Example 1 has a distinct triangular cross-section at the micrometer scale, and the groove array is regular and orderly.

[0101] Comparative Example 1 differs from Example 1 in that it uses a different carbon precursor material. The SEM image of the graphene film in Comparative Example 1 is shown below. Figure 3 As shown in the figure, the upper layer is laser-induced graphene (LIG) and the lower layer is polyimide (PI). The graphene film does not have a uniform structure and the array structure is not obvious. Specifically, it is a porous graphene with disordered micro-nano structures, without regular groove arrays, and without triangular cross-sections.

[0102] In Comparative Example 2, the scanning distance during laser processing exceeded the range defined in this invention. The image of the graphene film obtained in Comparative Example 2 under a laser confocal microscope is shown below. Figure 4 As shown, the three-dimensional image of the graphene film is no longer a triangular cross-section, but an array of grooves formed by multiple linear laser scans. At the same time, the generated graphene film has a low thickness and poor electrical conductivity.

[0103] The graphene films obtained in Example 1 and Comparative Example 1 were used to prepare capacitors, and the prepared capacitors were then tested. Figure 5 The current-voltage curve and potential-time curve of the capacitor prepared from the graphene film in Example 1 are shown. Figure 6 The current-voltage curve and potential-time curve of the capacitor made from the graphene film of Comparative Example 1 are shown in the figure. As can be seen from the figure, under the same current density, the capacitor of Example 1 has a longer charge-discharge time and a higher isal capacitance value, reaching 15.06 mF / cm. 2 .

[0104] The technical principles of the present invention have been described above with reference to specific embodiments. These descriptions are merely for explaining the principles of the invention and should not be construed as limiting the scope of protection of the invention in any way. Based on this explanation, those skilled in the art can readily conceive of other specific embodiments of the invention without inventive effort, and these embodiments will all fall within the scope of protection of the present invention.

Claims

1. A method for processing a micron-sized triangular cross-section grooved array graphene film, characterized in that, Includes the following steps: A. Pre-treat the flexible sheet material to obtain a flexible sheet substrate; B. Based on the required thickness of the solid carbon precursor, the carbon precursor material is coated onto a flexible thin film substrate and cured to obtain a flexible composite film loaded with solid carbon precursor. The carbon precursor material has a triazine ring-network cross-linked structure; C. Adjust the laser parameters and use the laser source to perform direct writing scanning on the surface of the solid carbon precursor, then clean and dry to obtain a micron-sized triangular cross-section groove array graphene film.

2. The method for processing a micron-sized triangular cross-section grooved array graphene film according to claim 1, characterized in that: In step C, the laser parameters include a laser wavelength of 200–360 nm, a pulse width of less than 12 picoseconds, a laser power of 3–5 W, and a defocusing method for unidirectional overlapping linear laser scanning. The spacing of the laser unidirectional overlapping linear scanning is 20-60% of the spot size, the defocusing amount is -2 to -8 mm, and the scanning speed is 80-150 mm / s.

3. The method for processing a micron-sized triangular cross-section grooved array graphene film according to claim 1, characterized in that: In step B, the carbon precursor material is one of cyanate ester resin, polytriazine polymer, and conjugated triazine polymer; The thickness of the carbon precursor material is 60–150 μm.

4. The method for processing a micron-sized triangular cross-section grooved array graphene film according to claim 1, characterized in that: The flexible sheet material is one of polyimide, polyethylene terephthalate, polyetherimide, polyethylene naphthalate, and MXene; and the flexible sheet material is in the form of a flexible film material or a flexible paper-based material. The thickness of the flexible sheet material is 30–150 μm.

5. The method for processing a micron-sized triangular cross-section grooved array graphene film according to claim 4, characterized in that: When the flexible sheet material is in the form of a flexible film material, in step A, the pretreatment is a hydrophilization treatment, and the contact angle of the pretreated flexible sheet material is less than 90°; The hydrophilization treatment is one of oxidation treatment, plasma treatment, coating with a surface activator, and laser engraving modification.

6. The method for processing a micron-sized triangular cross-section grooved array graphene film according to claim 5, characterized in that, When the hydrophilization treatment is laser engraving modification, step A includes the following steps: The flexible sheet material is placed at the focal point, and a laser light source is used to scribble a grid on the flexible sheet material to complete the hydrophilic treatment; The laser source has a wavelength of 200–360 nm, a pulse width of less than 12 picoseconds, a laser power of 6–8 W, a laser scanning speed of 600–900 mm / s, and a scanning spacing of 60–100 μm.

7. The method for processing a micron-sized triangular cross-section grooved array graphene film according to claim 5, characterized in that, In step B, the operation of coating the carbon precursor material onto the flexible sheet substrate is as follows: a mask is attached to the flexible sheet substrate, the mask has an opening not smaller than the pretreatment area, the opening corresponds to the pretreatment area, and the thickness of the mask is consistent with the thickness of the required carbon precursor. A carbon precursor material is coated in the pretreatment area, and then the excess carbon precursor material is scraped off to control the thickness of the carbon precursor material. The opening of the mask is processed by one of the following methods: physical cutting, photolithography, etching, and laser processing.

8. The method for processing a micron-sized triangular cross-section grooved array graphene film according to claim 4, characterized in that: When the flexible sheet material is in the form of a flexible paper-based material, the pretreatment method in step A is one of the following: impregnation, coating, and spin coating.

9. The method for processing a micron-sized triangular cross-section grooved array graphene film according to claim 8, characterized in that, In step B, the operation of coating the carbon precursor material onto the flexible sheet substrate is as follows: the carbon precursor material is completely dissolved in a solvent to obtain a carbon precursor solution. A carbon precursor solution is spin-coated onto a flexible sheet substrate to the required thickness using a spin coater.

10. The method for processing a micron-sized triangular cross-section grooved array graphene film according to claim 1, characterized in that: In step C, the atmosphere of the laser source is one of the following: an air atmosphere, an inert protective gas atmosphere, an oxygen / inert gas mixture environment, and a vacuum environment.

Images