Processing method of micron triangular cross section groove array graphene film

Abstract

The invention discloses a method for processing a micron triangular section groove array graphene film, which comprises the following steps of: A, pretreating a flexible sheet material to obtain a flexible sheet substrate; b, coating a carbon precursor material on a flexible sheet substrate according to the thickness of a required solid carbon precursor, and curing to obtain a flexible composite film loaded with the solid carbon precursor; the carbon precursor material has a triazine ring network cross-linked structure; and C, adjusting laser parameters, performing direct writing scanning on the surface of the solid carbon precursor by using a laser light source, and then cleaning and drying to obtain the micron triangular cross section groove array graphene film. According to the processing method of the micron triangular cross section groove array graphene film, the problems that the high precision and the three-dimensional performance of a graphene film micro-nano structure are difficult to meet, the process is complex, the quality control is difficult and the controllability is low in the current traditional processing process are solved.

Description

Technical Field

[0001] The present invention relates to the field of graphene film processing, and in particular to a method for processing a graphene film with a micron triangular cross-section groove array. Background Art

[0002] Graphene materials have excellent mechanical, optical, and electrochemical properties, and have important application values in various fields such as electronic information, energy, and materials.

[0003] In the field of electronic devices, with the continuous development of electronic devices towards miniaturization and high performance, higher requirements are put forward for the conductivity, stability, and specific surface area of electrode materials, and the demand for graphene films that can provide a higher effective specific area and have a periodic array structure also increases accordingly.

[0004] At present, the preparation technologies of graphene films include chemical vapor deposition method, liquid phase exfoliation method, chemical reduction method, etc. However, for graphene films that need to achieve trench arraying at the micro-nano scale to achieve a higher effective specific area and periodic array structure, traditional processing techniques such as chemical vapor deposition method, liquid phase exfoliation method, chemical reduction method, etc. have difficulties in quality control of the generated graphene, high cost, and complex processes, and cannot meet the requirements of high precision and three-dimensionalization of graphene micro-nano structures.

[0005] On the basis of achieving trench arraying at the micro-nano scale, further defining a graphene film with a triangular cross-section has regular longitudinal channels, can effectively disperse external stress, reduce stress concentration, has excellent durability under cyclic loading, and maintains the high mechanical stability of graphene. To prepare the above-mentioned graphene film with a micron triangular cross-section groove array, it is usually necessary to achieve it through the methods of template and lithography. The production is complex. If you want to adjust the structure, you need to prepare a template again. The controllability is low, the structure design is difficult, and the process is complex. Summary of the Invention

[0006] Aiming at the above defects, the purpose of the present invention is to propose a method for processing a graphene film with a micron triangular cross-section groove array, to solve the problems that the current traditional processing techniques are difficult to meet the high precision and three-dimensionalization of graphene film micro-nano structures, the process is complex, the quality control is difficult, and the controllability is low.

[0007] To achieve this purpose, the present invention adopts the following technical solutions:

[0008] A method for processing a graphene film with a micron triangular cross-section groove array, comprising the following steps:

[0009] A. Pretreat the flexible sheet material to obtain a flexible sheet substrate;

[0010] B. Coating a carbon precursor material on a flexible thin-film substrate according to the required thickness of the solid carbon precursor, and curing to obtain a flexible composite film loaded with the solid carbon precursor;

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

[0012] D. Adjusting the laser parameters, using a laser light source to perform direct writing scanning on the surface of the solid carbon precursor, and then cleaning and drying to obtain a graphene film with a micron triangular cross-section groove array.

[0013] Preferably, in step C, among the laser parameters, the laser wavelength is 200 - 360 nm, the pulse width is less than 12 picoseconds, the laser power is 3 - 5 W, and the laser is scanned unidirectionally and overlapped linearly in a defocused manner;

[0014] The spacing of the laser unidirectional overlapping linear scanning is 20 - 60% of the spot size, the defocus amount is -2 - -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 thin-film material is one of polyimide, polyethylene terephthalate, polyetherimide, polyethylene naphthalate, and MXene; and the form of the flexible thin-film material is a flexible film material or a flexible paper-based material;

[0018] The thickness of the flexible thin-film material is 30 - 150 μm.

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

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

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

[0022] Placing the flexible thin-film material at the focusing position, using a laser light source to perform grid scribing on the flexible thin-film material to complete the hydrophilic treatment;

[0023] The wavelength of the laser light source is 200 - 360 nm, the pulse width is less than 12 picoseconds, the laser power is 6 - 8 W, the laser scanning speed is 600 - 900 mm / s, and the scanning pitch is 60 - 100 μm.

[0024] Preferably, in step B, the operation of coating the carbon precursor material on the flexible thin-film substrate is as follows: a mask is attached to the flexible thin-film substrate, the mask is provided with an opening not smaller than the pretreatment area, the opening corresponds to the pretreatment area, and the thickness of the mask is the same as the required thickness of the carbon precursor;

[0025] The 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 processing method of the opening of the mask is one of physical cutting, photolithography technology, etching technology, and laser processing.

[0027] Preferably, when the form of the flexible thin-film material is a flexible paper-based material, in step A, the pretreatment method is one of the dipping method, the coating method, and the spin coating method.

[0028] Furthermore, in step B, the operation of coating the carbon precursor material on the flexible thin-film substrate is as follows: the carbon precursor material is completely dissolved in a solvent to obtain a carbon precursor solution;

[0029] The carbon precursor solution is spin-coated on the flexible thin-film substrate according to the required thickness by using a spin coater.

[0030] Preferably, in step C, the atmosphere of the laser light 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 the present invention may include the following beneficial effects:

[0032] By using a carbon precursor material with a triazine ring network cross-linked structure, which is loaded on a high-temperature resistant flexible thin-film material, and directly writing and scanning through certain laser parameters, while forming graphene, a corresponding micro-nano structure is formed, realizing high-precision processing and three-dimensionalization of the graphene thin film, and the process is simple; in addition, by limiting the range of laser parameters, within this range, a triangular cross-section groove array graphene thin film with good quality can be obtained, and by adjusting the parameters within the range, the size of the micro-nano structure can be correspondingly adjusted, thereby adjusting the performance of the device, and the controllability is high. Description of the Drawings

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

[0034] Figure 2It is the confocal laser microscope image of Example 1 of the present invention.

[0035] Figure 3 It is the SEM cross-sectional image of Comparative Example 1 of the present invention.

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

[0037] Figure 5 It is the volt-ampere curve and potential-time curve of the capacitor corresponding to Example 1 of the present invention.

[0038] Figure 6 It is the volt-ampere curve and potential-time curve of the capacitor corresponding to Comparative Example 1 of the present invention. Detailed implementation manners

[0039] The technical solution of the present invention will be further described below through specific implementation manners.

[0040] For the convenience of understanding the present invention, the present invention will be described more comprehensively below. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0041] For those not specified in the embodiments in terms of specific technologies or conditions, they shall be carried out according to the technologies or conditions described in the literature in this field or according to the product specifications. For the reagents or instruments not specified in terms of the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0042] A processing method for a graphene film with a micron triangular cross-section groove array includes the following steps:

[0043] A. Pretreat the flexible sheet material to obtain a flexible sheet substrate;

[0044] B. Coat the carbon precursor material on the flexible sheet substrate according to the required thickness of the solid carbon precursor, and cure it to obtain a flexible composite film loaded with the solid carbon precursor;

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

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

[0047] With the continuous development of electronic devices towards miniaturization and high performance, in order to meet the requirements of corresponding flexible devices, graphene films with higher effective specific area and periodic array structure are needed. However, the quality control of graphene films generated by traditional processing techniques is difficult, the cost is high, and the process is relatively complex, which cannot meet the requirements for the high precision and three-dimensionalization of graphene films in micro-nano structures. Moreover, when the electrical, mechanical, and chemical property requirements of the device change, it is necessary to remake the template, with low controllability and high cost.

[0048] Therefore, the present invention proposes a processing method for a graphene film with a micron triangular cross-section trench array. By using an ultraviolet ultrafast laser to perform direct writing scanning on a solid carbon precursor loaded on a flexible composite film, the requirements for the high precision and three-dimensionalization of the graphene film in micro-nano structures are realized. Using a laser light source for direct writing scanning is an efficient, low-cost, and high-precision micro-nano processing technology for material synthesis and conversion, with the ability of fast processing with high efficiency and high precision, and also has broad material compatibility and a wide processing range. In addition, due to the non-contact and high-speed characteristics of using an ultraviolet ultrafast laser for direct writing scanning, the complex process of mask preparation in traditional lithography technology is effectively avoided. By regulating specific laser parameters, various micro-nano structures of graphene films can be efficiently prepared to achieve three-dimensionalization, and then the quality of graphene can be macroscopically regulated.

[0049] Meanwhile, the carbon precursor material used in the present invention has a triazine ring network cross-linked structure after curing. The polymer with the triazine ring network cross-linked structure is connected by multi-point covalent bonds to form a highly cross-linked structure, enabling the carbon precursor with the triazine ring network cross-linked structure to have excellent mechanical properties, thermal stability and chemical tolerance. After ultraviolet ultrafast laser irradiation and scanning, it can effectively control the heat diffusion in the laser irradiation area, and will not burn and expand in size on a large scale during the laser processing. While ensuring high processing accuracy, it is not prone to thermal deformation and surface damage. Moreover, the high cross-linking property of this structure makes the surface after laser processing relatively flat, and can quickly maintain the formed micro-nano structure after the laser is removed. In addition, on the flexible composite film loaded with the solid carbon precursor, direct writing and scanning with a laser light source can directly synthesize graphene. The intense laser beam can generate extremely high temperatures on the target material, which is sufficient to break the chemical bonds of the material and prompt the rearrangement of carbon atoms into graphene. According to steps A to C for processing, the flexible sheet material is pretreated, and the obtained 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 groove structure. The morphology and size of the micro-nano groove structure can be precisely controlled 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, solving the problems that the current traditional processing technology is difficult to meet the high precision and three-dimensionalization of the graphene film micro-nano structure, unable to control the morphology and size of the micro-nano structure, and difficult in quality control.

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

[0051] Preferably, in step C, among the laser parameters, the laser wavelength is 200 - 360 nm, the pulse width is less than 12 picoseconds, the laser power is 3 - 5 W, and the laser is scanned linearly in a single direction with defocusing;

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

[0053] The graphene film with a grooved array of triangular cross-sections at the micron scale can enhance charge transport, reduce charge accumulation and local supersaturation, improve the performance of electrochemical reactions, and increase mechanical stability. The graphene film with this structure needs to be formed by processing a solid carbon precursor using a laser light source under certain laser parameters. Defining the laser parameters can ensure the full superposition and co-action 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 constructing the micro-nano scale structure of graphene, and forming a grooved array graphene film with a triangular cross-section. Specifically, on the one hand, it is the Gaussian effect of the laser. The intensity distribution of the laser beam follows a Gaussian distribution. In the central region of the laser beam, the energy density is the highest, and as the distance from the center increases, the energy density gradually decreases. When performing linear scanning, this energy distribution will cause different regions of the material surface to be heated to different degrees. The concentrated energy in the central part will cause excessive ablation of graphene, forming a grooved array on the material surface, where the lowest part of the groove corresponds to the region with the highest laser energy. On the other hand, it is the influence of the Marangoni effect. The Marangoni effect refers to the flow phenomenon generated inside a liquid due to the uneven distribution of surface tension under a temperature gradient. When the laser beam irradiates the carbon precursor material, due to the high energy input of the laser, the material will quickly heat up and transform into a high-temperature molten state. In this state, the fluidity of the material is greatly improved, and the Marangoni effect begins to play a role. Since the energy density at the center of the laser beam is the highest, the molten carbon material formed in the central region will flow to the two sides with lower energy due to the difference in surface tension, resulting in the stacking of the molten carbon material on both sides of the laser beam path, and finally forming a micro-nano structure with a triangular cross-section. Through the synergistic effect of the Gaussian effect and the Marangoni effect of the laser, a carbonized layer is formed on the upper surface of the solid carbon precursor, and the uncarbonized carbon precursor in the lower layer will also be affected by the laser and flow. The upper and lower layers together form a composite micro-nano structure, that is, the laser light source can prepare a graphene film with a fine micro-nano structure, and more specifically, it can prepare a grooved array graphene film with a triangular cross-section.

[0054] Among them, the laser wavelength is limited to 200-360 nm and the pulse width is less than 12 picoseconds, which can ensure the absorption rate of the carbon precursor material to the laser, that is, it can absorb laser energy more effectively, thereby improving the processing efficiency and quality; at the same time, the pulse width is less than 12 picoseconds, and the short pulse width can generate a high energy density on the surface of the carbon precursor, ensuring the accuracy of laser processing and meeting the requirements of micro-nano structures. The laser power is limited to 3-5 W, which is adapted to the performance of the carbon precursor with a triazine ring network cross-linked structure, and can avoid the damage of surface structures such as phase explosion. Within the limited scanning speed range, the corresponding laser power can meet the conditions for the generation of high-quality graphene and meet the requirements of quality control, reducing the occurrence of insufficient coverage and poor micro-structure morphology regularity. For the defocus amount, too small defocus amount will make the laser spot too small during laser scanning, and the energy is highly concentrated, which is prone to over-etching or over-etching. Too large defocus amount will disperse the laser energy and it is not easy to form a trench array structure. Therefore, the defocus amount is limited to -2 to -8 mm to ensure that the trench structure of the graphene film can be formed and regular. In addition, for the linear scanning interval, too small linear scanning interval will lead to dense laser irradiation and is prone to over-etching, while too large linear scanning interval will lead to incomplete coverage of the graphitized area and the required micro-nano structure cannot be formed. Therefore, the interval of the unidirectional overlapping linear scanning of the laser is limited to 20-60% of the spot size, that is, 16-47 μm, to ensure that the cross-sectional morphology and height difference are within the required range, that is, a regular triangular cross-section is formed, preventing the transformation, damage and disorder of the micro-nano structure and 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 depth-to-width ratio ranges from 0.2 to 1.5. Beyond this range, problems such as poor graphene quality, incomplete graphene coverage, over-etching and structural disorder will occur. Within the limited laser parameter range of the present invention, especially the defocus amount, scanning spacing and laser power, the size, spacing and height difference of the triangular trench array can be adjusted according to the requirements without exceeding the limited range of the height difference and depth-to-width ratio, and then the electrical, mechanical and chemical properties of the device can be adjusted, providing flexibility for the performance optimization of energy storage devices and sensors. Specifically, under the condition of single-factor variation, the scanning spacing during the laser linear overlapping scanning mainly has a significant impact on the bottom length and height of the triangle in the cross-section, while the change of the laser power represents the change of the laser energy density. The fine adjustment of the laser energy density can control the increase and decrease of the height difference of the trench array structure. For example, when the laser power increases, the height difference of the trench becomes larger, which can be adjusted according to the requirements, with high controllability, no need to remake the template, and the cost is reduced.

[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] In terms of the generation of graphene, the thickness, quality, and generation conditions of graphene generated by different carbon precursor materials are different. The carbon precursor material has a triazine ring network cross-linked structure after curing, specifically one of cyanate ester resin, polytriazine polymers, and conjugated triazine polymers, ensuring that the prepared graphene film has a regular array structure, with a neat structure, not easily disordered, and having good mechanical stability, laying a foundation for laser processing, and ensuring that the corresponding structure can be adjusted by controlling laser parameters to obtain the required performance.

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

[0060] Preferably, the carbon precursor material is cyanate ester resin. Cyanate ester resin has good thermal stability and conductivity, adjustable specific surface area and pore structure, good compatibility with graphene, and good structure forming stability, which is beneficial to the formation of a graphene film with a corresponding structure.

[0061] Preferably, the flexible sheet material is one of polyimide, polyethylene terephthalate, polyetherimide, polyethylene naphthalate, and MXene; and the form of the flexible sheet material is 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 are beneficial to maintaining the dimensional stability during processing.

[0064] At the same time, the flexible sheet material as the substrate plays the role of a flexible load, does not affect the preparation of subsequent flexible devices. The thickness of the flexible sheet material is 30 - 150 μm, which not only ensures the flexible effect but also avoids too high cost, is suitable for the laser scanning processing technology, will not be damaged due to being penetrated by laser scribing, and is not easily warped due to thermal stress concentration.

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

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

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

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

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

[0070] Place the flexible thin sheet material at the focusing position, and use a laser light source to perform grid scribing on the flexible thin sheet material to complete the hydrophilic treatment;

[0071] The wavelength of the laser light source is 200 - 360 nm, the pulse width is less than 12 picoseconds, the laser power is 6 - 8 W, the laser scanning speed is 600 - 900 mm / s, and the scanning pitch is 60 - 100 μm.

[0072] Specifically, the above operations and corresponding parameters ensure the completion of the hydrophilic treatment, that is, using laser for modification treatment. Place the flexible thin sheet material at the focusing position to ensure that the laser beam performs pattern scribing when the light spot is the smallest, preventing excessive ablation. The defined laser parameters ensure that the polyimide has a high enough absorption rate for the laser, enabling effective completion of the subsequent grid scribing operation, and the defined scanning pitch ensures the best hydrophilic effect for the scribed pattern.

[0073] Preferably, in step B, the operation of coating the carbon precursor material on the flexible thin sheet substrate is as follows: Attach a mask to the flexible thin sheet substrate. The mask has an opening not smaller than the pretreatment area, and the opening corresponds to the pretreatment area. The thickness of the mask is the same as the thickness of the required carbon precursor;

[0074] Coat the carbon precursor material in the pretreatment area, and then scrape off the excess carbon precursor material to control the thickness of the carbon precursor material;

[0075] The processing method of the opening of the mask is one of physical cutting, photolithography technology, etching technology, and laser processing.

[0076] Specifically, a mask with an opening is closely attached 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 a micro-container with an opening, and then a carbon precursor material is filled. The thickness of the mask is 60 - 150 μm, which is consistent with the thickness of the required carbon precursor, achieving the control of its thickness.

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

[0078] Preferably, the shape of the opening of the mask is the same as that of the pretreatment area, and can be rectangular, triangular or rhombic.

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

[0080] Specifically, the flexible paper-based material itself has porous looseness and can absorb the carbon precursor material by itself. Using the impregnation method, coating method or spin coating method, a flexible paper-based material that uniformly absorbs the carbon precursor material is obtained, which is beneficial to loading more carbon precursor materials on its surface subsequently. When the carbon precursor material is coated on the flexible sheet substrate in step B, it can prevent the paper-based material from absorbing the carbon precursor material, resulting in difficult coating, and can also prevent the surface structure from being disordered during the subsequent laser processing, which affects the preparation of the micro-nano groove structure.

[0081] Preferably, the pretreatment is the impregnation method. Cyanate ester resin is selected as the carbon precursor material, and the cyanate ester resin is uniformly dissolved in a solvent. The volume ratio of the cyanate ester resin to the solvent is 1:2 to obtain a carbon precursor solution. The flexible paper-based material is pretreated by the impregnation method, and the paper-based material is immersed in the carbon precursor solution for 10 - 30 minutes. At least 10 minutes is ensured to make the carbon precursor solution fully penetrate into the flexible paper-based material. The carbon precursor solution used must be the same as the carbon precursor material to be coated subsequently, meeting the material requirements of having a triazine ring network cross-linked structure after curing. Then it is taken out and dried at 50 - 80 °C for 30 - 60 minutes to remove the solvent, and the pretreatment is completed. The solvent can be an organic solvent such as acetone, toluene, methyl ethyl ketone, etc., which is used to adjust the viscosity and fluidity of the resin.

[0082] Furthermore, in step B, the operation of coating the carbon precursor material on the flexible sheet substrate is: completely dissolving the carbon precursor material in a solvent to obtain a carbon precursor solution;

[0083] Using a spin coater, the carbon precursor solution is spin-coated on the flexible sheet substrate according to the required thickness.

[0084] Specifically, a solvent that can effectively dissolve the carbon precursor material and will not react with the carbon precursor material is selected, and it can volatilize after heating to avoid introducing other components during processing. After the pretreatment in step A, that is, after the flexible paper-based material absorbs sufficient carbon precursor material, a flexible thin-film substrate that is conducive to loading is formed. In step B, spin coating is also required to load the carbon precursor on its surface. The carbon precursor solution is evenly spin-coated on the flexible thin-film substrate by a spin coater to control the thickness of the carbon precursor.

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

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

[0087] Specifically, defining the atmosphere can ensure that no other irrelevant chemical reactions occur during the process of generating graphene and ensure the quality of graphene.

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

[0089] Example 1

[0090] A. Stick the polyimide film tightly on the glass sheet. The size of the carrier glass sheet is 120 mm × 60 mm × 3 mm. Cut off the part of the polyimide film that is larger than the carrier glass sheet, and repeatedly press it firmly with an acrylic rod. After cleaning and drying, use a 355 nm, 10 ps ultraviolet picosecond laser for grid scribing and hydrophilic treatment to obtain a flexible thin-film substrate; among them, the defocus amount of laser engraving is 0 mm, the laser power is 8 W, the scanning speed is 500 mm / s, the designed grid pattern is a rectangle of 50 mm × 40 mm, the spacing of the grid is 64 μm, and the thickness of the polyimide film is 120 μm;

[0091] B. Select a commercially available solid polyimide film as the mask. Use a 355 nm, 10 ps ultraviolet picosecond laser to engrave a 100 mm × 40 mm rectangular opening on a 120 mm × 60 mm polyimide film, which is adapted to the size of the hydrophilic treatment grid pattern in step A. Press the mask tightly against the polyimide film, and repeatedly press and reinforce it with tweezers and a small acrylic rod. Select a commercially available cyanate ester resin as the carbon precursor material and heat it to 120° on a heating table. Coat it on the opening area of the mask, that is, the hydrophilic treatment area. Use a coating rod to scrape off the cyanate ester resin higher than the mask evenly, and cure it to obtain a flexible composite film loaded with the solid carbon precursor. Among them, the defocus amount of laser engraving is 0 mm, the laser power is 7 W, and the scanning speed is 60 mm / s. The thickness of the mask is 120 μm, and the size of the solid carbon precursor, that is, the solid cyanate ester resin, is 100 mm × 40 mm × 0.12 mm;

[0092] C. Use an ultraviolet picosecond laser to perform laser unidirectional overlapping linear scanning on the surface of the solid carbon precursor of the flexible composite film in a defocused manner, then wash it with deionized water, and dry it using a constant temperature heating table. Peel it from the carrier glass sheet to obtain a graphene film with a micron triangular cross-section groove array. Among them, the laser parameters are: the laser wavelength is 355 nm, the pulse width is 10 ps, the laser power is 4 W, the defocus amount is -2.8 mm, the scanning speed is 100 mm / s, and the spacing of the laser unidirectional overlapping linear scanning is 32 μm.

[0093] Control group

[0094] Control Example 1

[0095] Compared with Example 1, in Control Example 1, the polyimide film was directly used as the carbon precursor.

[0096] A. Press the polyimide film tightly on the glass sheet. The size of the carrier glass sheet is 120 mm × 60 mm × 3 mm. Cut off the part of the polyimide film larger than the carrier glass sheet, and repeatedly press it firmly with an acrylic rod, and perform cleaning and drying treatments;

[0097] B. Use an ultraviolet picosecond laser to perform laser unidirectional overlapping linear scanning on the surface of the solid carbon precursor of the flexible composite film in a defocused manner, then wash it with deionized water, and dry it using a constant temperature heating table. Peel it from the carrier glass sheet to obtain a graphene film. Among them, the laser wavelength is 355 nm, the pulse width is 10 ps, the laser power is 4 W, the defocus amount is -9 mm, the scanning speed is 100 mm / s, and the spacing of the laser unidirectional overlapping linear scanning is 26 μm.

[0098] Control Example 2

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

[0100] The SEM cross-sectional view of the graphene film obtained in Example 1 is as Figure 1 shown, and its image under the laser confocal microscope is as Figure 2 shown. It can be seen from the figure that the graphene film obtained in Example 1 has an obvious triangular cross-section at the micron scale, and the trench array is regular and orderly.

[0101] Compared with Example 1, the carbon precursor material used in Comparative Example 1 is different. The SEM image of the graphene film in Comparative Example 1 is as Figure 3 shown. It can be seen from the figure that the upper layer is laser-induced graphene (LIG), and the lower layer is polyimide (PI). This graphene film does not have a uniform structure, and the array structure is not obvious. Specifically, it is a porous graphene with a disordered micro-nano structure, without a regular trench array and even less a triangular cross-section.

[0102] During laser processing in Comparative Example 2, its scanning spacing exceeds the range defined by the present invention. The image of the graphene film obtained in Comparative Example 2 under the laser confocal microscope is as Figure 4 shown. It can be seen that the three-dimensional image of the graphene film is no longer a triangular cross-section, but an array trench after multiple linear laser scans, and at the same time, the thickness of the generated graphene film is low and the conductivity is poor.

[0103] The graphene films obtained in Example 1 and Comparative Example 1 were respectively used to prepare capacitors, and then the prepared capacitors were tested. Figure 5 are the volt-ampere curve and potential-time curve of the capacitor made of the graphene film in Example 1. Figure 6 are the volt-ampere curve and potential-time curve of the capacitor made of the graphene film in Comparative Example 1. It can be seen from the figure that at the same current density, the charge and discharge time of the capacitor in Example 1 is longer, and it has a higher specific capacitance value, up to 15.06 mF / cm 2 .

[0104] The technical principle of the present invention has been described above in conjunction with specific embodiments. These descriptions are only for explaining the principle of the present invention and cannot be construed in any way as a limitation on the protection scope of the present invention. Based on the explanations herein, those skilled in the art can readily conceive of other specific embodiments of the present invention without creative efforts, and these embodiments will fall within the protection scope of the present invention.

Claims

1. A processing method for a graphene film with a micron triangular cross-section groove array, characterized in that, It includes the following steps: A. Pretreat the flexible sheet material to obtain a flexible sheet substrate; B. Coat the carbon precursor material on the flexible sheet substrate according to the required thickness of the solid carbon precursor, and cure it to obtain a flexible composite film loaded with the solid carbon precursor; The carbon precursor material has a triazine ring network cross-linked structure; C. Adjust the laser parameters, use a laser light source to perform direct writing scanning on the surface of the solid carbon precursor, and then clean and dry it to obtain a graphene film with a micron triangular cross-section groove array.

2. The processing method of a micron triangular cross-section groove array graphene film according to claim 1, characterized in that: In step C, among the laser parameters, the laser wavelength is 200 - 360 nm, the pulse width is less than 12 picoseconds, the laser power is 3 - 5 W, and the laser is scanned unidirectionally and linearly in an off-focus manner; The spacing of the unidirectional overlapping linear scanning of the laser is 20 - 60% of the spot size, the defocus amount is -2 - -8 mm, and the scanning speed is 80 - 150 mm / s.

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

4. The processing method of a micron triangular cross-section groove 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 form of the flexible sheet material is a flexible film material or a flexible paper-based material; The thickness of the flexible sheet material is 30 - 150 μm.

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

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

7. The processing method of a micron triangular cross-section groove array graphene film according to claim 5, characterized in that, In step B, the operation of coating the carbon precursor material on the flexible sheet substrate is: attach a mask on the flexible sheet substrate, the mask is provided with an opening not smaller than the pretreatment area, the opening corresponds to the pretreatment area, and the thickness of the mask is the same as the required thickness of the carbon precursor; Coat the carbon precursor material in the pretreatment area, and then scrape off the excess carbon precursor material to control the thickness of the carbon precursor material; The processing method of the opening of the mask is one of physical cutting, photolithography technology, etching technology, and laser processing.

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

9. The processing method of a micron triangular cross-section groove array graphene film according to claim 8, characterized in that, In step B, the operation of coating the carbon precursor material on the flexible sheet substrate is: completely dissolve the carbon precursor material in a solvent to obtain a carbon precursor solution; Use a spin coater to spin coat the carbon precursor solution on the flexible sheet substrate according to the required thickness.

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

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