TWI747699B - Method for preparing laser-induced graphene - Google Patents

Abstract

A method for preparing laser-induced graphene, comprising providing a substrate; and adjusting a laser light source and a far-infrared auxiliary light source to irradiate the substrate, and further forming a laser light-induced graphene on a surface of the substrate. By combining the technical features of the method with the far-infrared auxiliary light source, the present invention can effectively improve the defect and the electrical properties of the laser-induced graphene.

Description

Method for preparing graphene induced by laser light

The present invention relates to a preparation method of graphene, in particular to a preparation method of graphene induced by laser light.

In recent years, Graphene nanomaterials are due to their unique physical and chemical properties (such as high surface area, high conductivity, good mechanical strength, etc.), and their applications in the fields of biology, materials, energy, and communications. Potential, and received widespread attention from all over the world. In the past, common preparation methods for graphene include physical mechanical peeling, chemical vapor deposition, etc., which usually involve high-temperature processing or multi-step chemical synthesis, and the process is complicated and difficult to pattern.

Until 2014, laser-induced graphene (LIG) and related preparation methods were proposed, which greatly changed the ecology of the graphene preparation process. Laser-induced graphene is a material that is directly written on a carbon substrate through laser light in an ordinary atmospheric environment; this technology can not only combine the preparation of 3D graphene with patterning, but also does not require traditional wet chemistry Steps; significantly reduce processing costs. Since then, laser light-induced graphene has aroused extensive research interest; in addition to the discussion of the mechanism itself, its application in the fields of energy, sensing, and environment is also quite worth looking forward to.

However, the laser light-induced graphene made by direct writing with laser light is often found to have many defects after being measured by Raman spectroscopy. Regarding the defect of graphene induced by laser light, researchers in the field of the present invention have also proposed different solutions, such as adjusting the choice of carbon substrate or laser light source, and the number of passes of the laser light. Based on this, it can be understood that how to adjust the laser light-induced graphene process to improve the defect status is a problem that needs to be solved urgently in the field of the present invention.

The summary of the invention aims to provide a simplified summary of the invention so that readers have a basic understanding of the invention. This summary is not a complete overview of the invention, and its intention is not to point out important or key elements of the embodiments of the invention or to define the scope of the invention.

In view of the content mentioned in the prior art, the main purpose of the present invention is to provide a method for preparing laser-induced graphene; the method includes not only the laser light source for direct writing, but also the common use of far-infrared auxiliary light sources. , And then prepare laser-induced graphene with lower defects and better electrical properties.

Specifically, the present invention provides a method for preparing laser light-induced graphene, which includes the following steps. First, a substrate is provided; then, a laser light source and a far-infrared auxiliary light source are adjusted to irradiate the substrate, and then a laser light-induced graphene is formed on a surface of the substrate. According to some embodiments of the present invention, the substrate includes a polymer; and further, the polymer is a polyimide (PI, Polyimide) or a polyetherimide (PEI, Polyetherimide).

According to some embodiments of the present invention, the form of the substrate is an electronic circuit substrate, a flexible substrate, a rigid substrate, a film, a mass, a powder, or any combination thereof.

According to some embodiments of the present invention, the laser light source is a CO ₂ laser light source, a UV laser light source, a visible light laser light source, or a fiber laser light source.

According to some embodiments of the present invention, adjusting the laser light source includes adjusting one or more parameters of the laser light source; and further, the one or more parameters of the laser light source are laser light wavelength, laser light power, The energy density of the laser light, the distance between the laser light source and the substrate, the frequency of the laser light, the laser scanning rate, the laser scanning path, the distance between the laser scanning paths, or any combination thereof.

According to some embodiments of the present invention, adjusting the far-infrared auxiliary light source includes adjusting one or more parameters of the far-infrared auxiliary light source; and further, the one or more parameters of the far-infrared auxiliary light source are far-infrared auxiliary light source power , The distance between the far-infrared auxiliary light source and the substrate or any combination thereof.

According to some embodiments of the present invention, the laser light-induced graphene is a single-layer graphene, a multi-layer graphene, a porous graphene, an unfunctionalized graphene, a functionalized graphene, or any combination thereof.

In order to make the description of the present invention more detailed and complete, the following provides an illustrative description for the implementation aspects and specific embodiments of the present invention, but this is not the only way to implement or use the specific embodiments of the present invention. In the scope of this specification and the appended patent application, unless the context clarifies otherwise, "a" and "the" can also be interpreted as plurals. In addition, in the scope of this specification and the appended patent application, unless otherwise stated, "installed on something" can be regarded as directly or indirectly in contact with the surface of something by attaching or other forms. The definition of the surface It should be judged based on the semantics of the preceding and following/paragraphs of the description and the general knowledge of the field to which this description belongs.

Although the numerical ranges and parameters used to define the present invention are approximate numerical values, the relevant numerical values in the specific embodiments have been presented here as accurately as possible. However, any value inherently inevitably contains standard deviations due to individual test methods. Here, "about" usually means that the actual value is within plus or minus 10%, 5%, 1%, or 0.5% of a specific value or a range. Or, the word "about" means that the actual value falls within the acceptable standard error of the average value, which is determined by those with ordinary knowledge in the field of the present invention. Therefore, unless otherwise stated to the contrary, the numerical parameters disclosed in this specification and the accompanying patent scope are approximate values and can be changed according to requirements. At least these numerical parameters should be understood as the indicated effective number of digits and the value obtained by applying the general carry method.

definition

Laser-induced graphene (LIG) refers to graphite made by direct writing of a laser light on a carbon substrate under a normal atmospheric pressure and normal temperature environment. Ene.

Raman spectra means a kind of vibrational spectroscopy. The principle is to use a laser light source with a fixed wavelength to excite the sample to be tested. When the excitation light interacts with the sample molecule, if the photon collides with the molecule, the collision occurs after the photon collides with the molecule. Energy exchange, the photon transfers part of the energy to the sample molecule or obtains a part of the energy from the sample molecule, thereby changing the frequency of the light; this change is the Raman shift. The amount of Raman shift does not change due to the wavelength of the laser, so it can be used to understand the molecular bonding and structure, and it can also further understand the environment of the molecule. For example, the impurities in the sample can be caused by stress and strain. ) Causes the bond to change and react in the Raman shift; the deformation of the compound in different states, such as melting and crystallization caused by heating or external force, will also have an impact.

Method of implementation

In order to solve the problems found on the basis of the prior art, the present invention proposes a method for preparing laser light-induced graphene. Fig. 1 is a flowchart of a method according to an embodiment of the present invention; as shown in Fig. 1, the method for preparing laser-induced graphene includes steps S1-S2. First, step S1 is to provide a substrate; next, step S2 is to adjust a laser light source and a far-infrared auxiliary light source to irradiate the substrate, and further form a laser light-induced graphene on a surface of the substrate. By combining the technical features of the method with the far-infrared auxiliary light source, the present invention can effectively improve the defect and electrical properties of the graphene induced by laser light.

Specifically, in step S2, adjusting the laser light source includes adjusting one or more parameters of the laser light source; furthermore, the one or more parameters are laser light wavelength, laser light power, laser light The energy density, the distance between the laser light source and the substrate, the frequency of the laser light, the laser scanning rate, the laser scanning path, the distance between the laser scanning paths, or any combination thereof.

On the other hand, in step S2, adjusting the far-infrared auxiliary light source includes adjusting one or more parameters of the far-infrared auxiliary light source; further speaking, one or more parameters of the far-infrared auxiliary light source are far-infrared auxiliary light sources Power, the distance between the far-infrared auxiliary light source and the substrate, or any combination thereof.

In addition, in step S2, the laser light induced graphene-based single-layer graphene, multi-layer graphene, porous graphene, unfunctionalized graphene, functionalized graphene, or any combination thereof.

FIG. 2A is a schematic diagram of a laser direct writing system according to an embodiment of the present invention, and FIGS. 2B and 2C are schematic diagrams of a light spot according to FIG. 2A. Please refer to Figs. 1-2C together. A laser light source 100 is arranged with a telecentric lens 102 facing a platform 110. A substrate 120 is placed on a surface of the platform 110 facing the telecentric lens 102, and the substrate 120 and the There is a distance Z1 between the telecentric lenses 102. At the same time, a far-infrared auxiliary light source 130 is arranged toward the substrate 120 to illuminate the substrate 120.

Specifically, the laser light source 100 is used to emit a laser light, which passes through the telecentric lens 102 and irradiates the surface of the substrate 120 to form a plurality of light spots 122. However, the laser light is basically focused on a focal plane 112, and the focal plane 112 is a distance Z2 from the telecentric lens 102. Based on this, it can be understood that if the distance Z2 is equal to the distance Z1, the laser light will mark the surface of the substrate 120 as shown in Figure 2B; and if the length of the distance Z1 is less than When the distance Z2, in other words, is in the up-defocus state, the laser light will mark the surface of the substrate 120 with a spot pattern as shown in FIG. 2C. On the other hand, the platform 110 can substantially move along the X and Y axes, so a laser scanning rate can be defined accordingly; thereby, the complex number of spots 122 can not only further form a specific laser based on the laser scanning rate In the scanning path aspect, a laser scanning path distance 124 can also be defined between the individual circle centers of the plurality of light spots 122. In detail, the form of the substrate 120 is an electronic circuit substrate, a flexible substrate, a rigid substrate, a film, a mass, a powder, or any combination thereof. In addition, the substrate 120 includes a polymer; and preferably, the polymer is a polyimide (PI, Polyimide) or a polyetherimide (PEI, Polyetherimide). In addition, the laser light source 100 is a CO ₂ laser light source, a UV laser light source, a visible light laser light source, or a fiber laser light source; preferably, the laser light source 100 is a UV laser light source, and more preferably , Which is a UV nanosecond pulse laser.

The content described below is mainly related to the measurement results of the laser light-induced graphene prepared in the first to fourth embodiments. It should be particularly noted that those with ordinary knowledge in the technical field of the present invention should understand that in the Raman spectrogram generated by measuring graphene with a Raman spectrometer, special attention should be paid to the G, D, and 2D peaks. Among them, the G peak generally appears at the position where the ^{Raman shift is about 1580 cm-1 ; it represents the vibration mode of the sp 2} bonding in graphene, and the observer can use it to understand the ^{integrity of the sp 2} bonding of the sample, and then infer The crystalline characteristics of the sample; ^{the D peak located at about 1270 to 1450 cm-1} expresses the characteristics of sample defects, amorphous carbon or graphite edges; and the generation of 2D peaks is closely related to the number of graphite layers.

Based on the foregoing, in the present embodiment, the material properties of graphene Ruoyu interpretation of samples, respectively, taking into account any peak intensity D / G peak intensity (hereinafter, referred to as I _D / I _G) of the peak intensity value and the 2D / G peak intensity ( Hereinafter, it is referred to as the value of _{I 2D} /I _{G ).} The _{higher the I 2D} / _IG value, the higher the defect degree of the graphene sample. The I _2D /I _G value is used to determine the number of graphene sample layers. When its value is between 1.5-2, it means that the sample is single-layer graphene; when its value is less than 1, it means that the sample is multi-layer graphene.

The first embodiment

The laser light source 100 is a CO ₂ laser light source, a UV laser light source, a visible light laser light source or a fiber laser light source; according to the first embodiment, the laser light source 100 is a UV nanosecond pulse laser, And the power of the laser light source 100 is adjusted to 3W. Accordingly, the distance Z1 can be adjusted to be between 15000-20000μm and be in a defocused state (in terms of the focal length of the UV laser, the distance Z2 is between 20000-30000μm); and according to the first embodiment In other words, the distance Z1 is 17000 μm. In addition, the frequency of the laser light source is 100kHZ; the distance between the laser scanning paths 124 is 0.05mm; and the laser scanning rate can be adjusted between 50-150mm/s. According to the first embodiment, The laser scanning rate is 100mm/s.

On the other hand, the form of the substrate 120 is an electronic circuit substrate, a flexible substrate, a rigid substrate, a film, a mass, a powder, or any combination thereof. In addition, the substrate 120 includes a polymer, and the polymer is a polyimide (PI, Polyimide) or a polyetherimide (PEI, Polyetherimide); according to the first embodiment, the polymer It is a polyimide (PI, Polyimide).

Then, Raman spectroscopy is performed on the laser light-induced graphene made with and without the far-infrared auxiliary light source 130 (the results of using and not using the far-infrared auxiliary light source 130 are shown in Figure 3A and Figure 3B, respectively) and electrical properties analyze. Wherein, the power of the far-infrared auxiliary light source 130 is between 200-400W; according to the first embodiment, it is 300W. As shown in section 3A and FIG. 3B, the far-infrared is not used auxiliary light source 130 of the I _D / I _G is 1.185, I _2D / I _G is 0.737; using the far infrared auxiliary light source 130. I _D / I _G value of 1.005, I _2D / I _G value of 0.789. Based on this, it can be understood that when the far-infrared auxiliary light source 130 is used, the degree of graphene defect is significantly reduced; and in both cases, multilayer graphene is produced. In addition, in terms of electrical results, when the far-infrared auxiliary light source 130 is not used, the resistance value of graphene is 17Ω, and when the far-infrared auxiliary light source 130 is used, the resistance value of graphene is 16Ω , Showing better electrical properties.

Second embodiment

The laser light source 100 is a CO ₂ laser light source, a UV laser light source, a visible light laser light source or a fiber laser light source; according to the second embodiment, the laser light source 100 is a UV nanosecond pulse laser, And the power of the laser light source 100 is adjusted to 3W. Accordingly, the distance Z1 can be adjusted to be between 15000-20000μm and be in a defocused state (in terms of the focal length of the UV laser, the distance Z2 is between 20000-30000μm); and according to the second embodiment In other words, the distance Z1 is 17000 μm. In addition, the frequency of the laser light source is 100kHZ; the distance between the laser scanning paths 124 is 0.05mm; and the laser scanning rate can be adjusted between 50-150mm/s. According to the second embodiment, The laser scanning rate is 125mm/s. On the other hand, the form of the substrate 120 is an electronic circuit substrate, a flexible substrate, a rigid substrate, a film, a mass, a powder, or any combination thereof. In addition, the substrate 120 includes a polymer, and the polymer is a polyimide (PI, Polyimide) or a polyetherimide (PEI, Polyetherimide); according to the second embodiment, the polymer It is a polyimide (PI, Polyimide).

Then, Raman spectroscopy analysis was performed on the laser light-induced graphene made with and without the far-infrared auxiliary light source 130 (the results of using and not using the far-infrared auxiliary light source 130 are shown in Figure 4A and Figure 4B, respectively) and electrical properties analyze. Wherein, the power of the far-infrared auxiliary light source 130 is between 200-400W; according to the second embodiment, it is 300W. As shown in FIG. 4A and FIG. 4B are not on the far-infrared auxiliary light source 130. I _D / I _G is 1.125, I _2D / I _G is 0.747; using the far infrared auxiliary light source 130. I _D / I _G value of 1.063, I _2D / I _G value of 0.738. Based on this, it can be understood that when the far-infrared auxiliary light source 130 is used, the degree of graphene defect is significantly reduced; and in both cases, multilayer graphene is produced. In addition, in terms of electrical results, when the far-infrared auxiliary light source 130 is not used, the resistance value of graphene is 22Ω, and when the far-infrared auxiliary light source 130 is used, the resistance value of graphene is 19Ω , Showing better electrical properties.

The third embodiment

The laser light source 100 is a CO ₂ laser light source, a UV laser light source, a visible light laser light source or a fiber laser light source; according to the third embodiment, the laser light source 100 is a UV nanosecond pulse laser, And the power of the laser light source 100 is adjusted to 4W. Accordingly, the distance Z1 can be adjusted to be between 15000-20000μm and be in a defocused state (in terms of the focal length of the UV laser, the distance Z2 is between 20000-30000μm); and according to the third embodiment In other words, the distance Z1 is 17000 μm. In addition, the frequency of the laser light source is 100kHZ; the distance between the laser scanning paths 124 is 0.05mm; and the laser scanning rate can be adjusted between 50-150mm/s. According to the third embodiment, The laser scanning rate is 50mm/s. On the other hand, the form of the substrate 120 is an electronic circuit substrate, a flexible substrate, a rigid substrate, a film, a mass, a powder, or any combination thereof. In addition, the substrate 120 includes a polymer, and the polymer is a polyimide (PI, Polyimide) or a polyetherimide (PEI, Polyetherimide); according to the third embodiment, the polymer It is a polyimide (PI, Polyimide).

Then, Raman spectroscopy is performed on the laser light-induced graphene made with and without the far-infrared auxiliary light source 130 (the results of using and not using the far-infrared auxiliary light source 130 are shown in Figure 5A and Figure 5B, respectively) and electrical properties analyze. Wherein, the power of the far-infrared auxiliary light source 130 is between 200-400W; according to the third embodiment, it is 300W. 5A and 5B as in the first shown in FIG not using the far-infrared auxiliary light source 130. I _D / I _G is 0.778, I _2D / I _G is 0.690; using the far infrared auxiliary light source 130. I _D / I _G value of 0.687, I _2D / I _G value of 0.832. Based on this, it can be understood that when the far-infrared auxiliary light source 130 is used, the degree of graphene defect is significantly reduced; and in both cases, multilayer graphene is produced. In addition, in terms of electrical results, when the far-infrared auxiliary light source 130 is not used, the resistance value of graphene is 12Ω, and when the far-infrared auxiliary light source 130 is used, the resistance value of graphene is 10Ω , Showing better electrical properties.

Fourth embodiment

The laser light source 100 is a CO ₂ laser light source, a UV laser light source, a visible light laser light source or a fiber laser light source; according to the fourth embodiment, the laser light source 100 is a UV nanosecond pulse laser, And the power of the laser light source 100 is adjusted to 5W. Accordingly, the distance Z1 can be adjusted to be between 15000-20000μm and be in a defocused state (in terms of the focal length of the UV laser, the distance Z2 is between 20000-30000μm); and according to the fourth embodiment In other words, the distance Z1 is 17000 μm. In addition, the frequency of the laser light source is 100kHZ; the laser scanning path distance 124 is 0.05mm; and the laser scanning rate can be adjusted between 50-150mm/s. According to the fourth embodiment, The laser scanning rate is 50mm/s.

On the other hand, the form of the substrate 120 is an electronic circuit substrate, a flexible substrate, a rigid substrate, a film, a mass, a powder, or any combination thereof. In addition, the substrate 120 includes a polymer, and the polymer is a polyimide (PI, Polyimide) or a polyetherimide (PEI, Polyetherimide); according to the first embodiment, the polymer It is a polyimide (PI, Polyimide).

Then, Raman spectroscopy is performed on the laser light-induced graphene made with and without the far-infrared auxiliary light source 130 (the results of using and not using the far-infrared auxiliary light source 130 are shown in Figure 6A and Figure 6B respectively) and electrical properties analyze. Wherein, the power of the far-infrared auxiliary light source 130 is between 200-400W; according to the fourth embodiment, it is 300W. As shown in FIG. 6B and 6A of not using the far-infrared auxiliary light source 130. I _D / I _G is 0.729, I _2D / I _G is 0.801; using the far infrared auxiliary light source 130. I _D / I _G value It is 0.587, and the I _2D /I _G value is 0.803. Based on this, it can be understood that when the far-infrared auxiliary light source 130 is used, the degree of graphene defect is significantly reduced; and in both cases, multilayer graphene is produced. In addition, in terms of electrical results, when the far-infrared auxiliary light source 130 is not used, the resistance value of graphene is 34Ω, and when the far-infrared auxiliary light source 130 is used, the resistance value of graphene is 12Ω , Showing better electrical properties.

In summary, it can be understood from the embodiments defined by the present invention and specific and different examples that through the method for preparing laser-induced graphene provided by the present invention, it is possible to obtain lower defects and better electrical properties. The laser light induces graphene.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention. Anyone with ordinary knowledge in the relevant technical field can make some changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be based on what is defined by the attached patent application scope.

S1-S2: steps 100: Laser light source 102: Telecentric lens 110: platform 112: focal plane 120: Substrate 122: light spot 124: Laser scanning path spacing 130: far-infrared auxiliary light source

In order to make the above and other objects, features, advantages and embodiments of the present invention easier to understand, the description of the accompanying drawings is as follows: Figure 1 is a flowchart of a method according to an embodiment of the present invention; Figure 2A is a schematic diagram of a laser direct writing system according to an embodiment of the present invention; Figures 2B and 2C are based on the schematic diagram of the light spot drawn in Figure 2A; Figures 3A-6B are graphene Raman spectrograms of an embodiment of the present invention.

According to the usual operation method, the various features and elements in the figure are not drawn according to the actual scale, and the drawing method is to present the specific features and elements related to the present invention in the best way. In addition, in different drawings, the same or similar element symbols are used to refer to similar elements and components.

S1~S2: steps

Claims (4)

A method for preparing laser light-induced graphene includes the following steps: providing a substrate, wherein the substrate includes a polyimide (PI, Polyimide) or a polyetherimide (PEI, Polyetherimide), and the The form of the substrate is an electronic circuit substrate, a flexible substrate, a rigid substrate, a film, a mass, a powder, or any combination thereof; and a laser light source and a far-infrared auxiliary light source are adjusted to irradiate the substrate, and then on one of the substrates A laser light-induced graphene is formed on the surface, where the power of the far-infrared auxiliary light source is between 200-400W; where the laser light source is a UV nanosecond pulse laser with power between 3-5W, The frequency is 100kHZ, and the scan rate is between 50-150mm/s. The method according to claim 1, further comprising adjusting the laser light wavelength of the laser light source, the laser light energy density of the laser light source, the distance between the laser light source and the substrate, and the laser scanning of the laser light source The path, or the distance between the laser scanning path of the laser light source. The method according to claim 1, further comprising adjusting the distance between the far-infrared auxiliary light source and the substrate. The method according to claim 1, wherein the laser light-induced graphene is a single-layer graphene, a multilayer graphene, a porous graphene, an unfunctionalized graphene, a functionalized graphene, or any combination thereof.

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