Laser transfer printing film preparation method and transfer printing film

Abstract

The invention provides a laser transfer printing film preparation method and a transfer printing film, and the method comprises the steps: providing a substrate which comprises a first surface and a second surface which are oppositely arranged; a plurality of grooves are formed in the direction, close to the second surface, of the first surface; an anti-reflection layer is prepared on the second surface, the anti-reflection layer is cured, and the second surface is covered with the anti-reflection layer; a hydrophobic and oleophobic layer is prepared on the first surface with the grooves, the hydrophobic and oleophobic layer is cured, and the first surface and the grooves are covered with the hydrophobic and oleophobic layer. On the basis of an existing laser transfer printing film structure, a transparent coating with hydrophobic and oleophobic characteristics is added to the front face, and slurry can be completely separated from a transfer printing template, so that silver slurry is saved, and the height-width ratio of a grid line is increased. In addition, an anti-reflection layer is additionally arranged on the back face, reflection loss generated when laser penetrates through the transfer printing film is reduced, enhancement of actual laser power is ensured, and then the use efficiency of the laser is improved.

Description

Technical Field

[0001] The invention relates to the field of solar cells, and in particular to a laser transfer film preparation method and a transfer film. Background Art

[0002] Laser transfer technology is an advanced printing technology that uses a laser beam to irradiate the grooves on the laser transfer film that is pre-filled with slurry, so that the slurry falls off the transfer film and is accurately transferred to the surface of the cell, thereby achieving accurate pattern transfer. However, in actual application, due to the complexity of the laser process and the matching problem of slurry adhesion, some technical difficulties often arise in the transfer process. For example, the gate line of laser transfer may be broken, that is, the gate line breaks during the transfer process and cannot form a complete conductive path; in addition, edge sputtering may also occur, that is, the slurry may sputter to the non-target area of ​​the cell under laser irradiation, affecting the accuracy and aesthetics of the pattern.

[0003] The existence of these problems makes the laser transfer technology face challenges in achieving accurate transfer of grid lines. At the same time, after the transfer film is used, a part of the slurry that has not fallen off will remain, which will not only lead to a reduction in the actual wet weight, thereby reducing the aspect ratio of the grid line and affecting the conductivity of the battery cell; moreover, these residual slurries will also make the laser transfer film unable to be reused, thereby increasing the cost of laser transfer technology. Therefore, how to solve the matching problem between the laser process and the adhesion of the slurry, improve the transfer accuracy, reduce the slurry residue, and realize the reuse of the transfer film has become a key problem that needs to be solved in laser transfer technology. Summary of the invention

[0004] The purpose of the present invention is to solve the problem that the laser transfer film in the prior art reduces the aspect ratio of the grid lines and has low transfer accuracy.

[0005] In a first aspect, the present invention provides a method for preparing a laser transfer film, comprising:

[0006] Providing a substrate, the substrate comprising a first surface and a second surface disposed opposite to each other;

[0007] A plurality of grooves are formed on the first surface in a direction close to the second surface;

[0008] Preparing an anti-reflection layer on the second surface and curing the anti-reflection layer, wherein the anti-reflection layer covers the second surface;

[0009] A hydrophobic and oleophobic layer is prepared on the first surface after the grooves are formed, and the hydrophobic and oleophobic layer is solidified, so that the hydrophobic and oleophobic layer covers the first surface and the grooves.

[0010] Furthermore, the hydrophobic and oleophobic layer is a transparent coating.

[0011] Furthermore, the groove is formed by a nano-imprinting method, and the groove is in an inverted trapezoidal shape.

[0012] Furthermore, before preparing the anti-reflection layer, the method further includes: cleaning the first surface and the second surface of the substrate.

[0013] Furthermore, the substrate is cleaned with deionized water, anhydrous ethanol and petroleum ether in sequence.

[0014] Furthermore, the anti-reflection layer or the hydrophobic and oleophobic layer is solidified by irradiating with an ultraviolet lamp.

[0015] Furthermore, the irradiation time of the ultraviolet lamp is 3 minutes to 5 minutes.

[0016] In a second aspect, the present invention provides a laser transfer film, which is prepared by the laser transfer film preparation method as described in any one of the above items, comprising:

[0017] A substrate, the substrate comprising a first surface and a second surface arranged opposite to each other, the first surface being provided with a plurality of grooves extending toward the second surface;

[0018] a hydrophobic and oleophobic layer, the hydrophobic and oleophobic layer being disposed on the first surface and covering the first surface and the first groove;

[0019] An anti-reflection layer is disposed on the second surface and covers the second surface.

[0020] Furthermore, the thickness of the substrate is 45 μm-75 μm.

[0021] Furthermore, the thickness of the anti-reflection layer is 0.3 μm-0.36 μm.

[0022] Furthermore, the hydrophobic and oleophobic layer has a thickness of 1 μm-2 μm.

[0023] Compared with the prior art, the present invention has at least the following beneficial effects: on the existing laser transfer film structure, by adding a layer of transparent coating with hydrophobic and oleophobic properties on the front side, the adhesion of alcohol ether and ester organic solvents to the transfer film surface is reduced. It helps the slurry to be completely separated from the transfer template, thereby saving the use of silver paste and improving the aspect ratio of the grid line. In addition, an anti-reflection layer is added on the back side to reduce the reflection loss when the laser penetrates the transfer film, ensuring the enhancement of the actual laser power, thereby improving the efficiency of laser use. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0025] Figure 1 This is a flow chart of a method for preparing a laser transfer film in one embodiment of the present invention;

[0026] Figure 2 This is a schematic diagram of the structure of a laser transfer film in one embodiment of the present invention;

[0027] Figure 3 A microscope image of a reference group of grid lines in one embodiment of the present invention;

[0028] Figure 4 This is a microscope image of the grid lines of the experimental group in one embodiment of the present invention.

[0029] Among them, 1-hydrophobic and oleophobic layer; 2-substrate; 3-anti-reflection layer. DETAILED DESCRIPTION

[0030] A method for preparing a laser transfer film and a transfer film of the present invention will be described in more detail below in conjunction with schematic diagrams, wherein preferred embodiments of the present invention are shown, and it should be understood that those skilled in the art may modify the present invention described herein while still achieving the advantageous effects of the present invention. Therefore, the following description should be understood as being widely known to those skilled in the art and not as a limitation of the present invention.

[0031] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0032] The present invention is described in more detail in the following paragraphs by way of example with reference to the accompanying drawings. The advantages and features of the present invention will become more apparent from the following description. It should be noted that the accompanying drawings are in very simplified form and are not in exact proportions, and are only used to facilitate and clearly assist in illustrating the purpose of the embodiments of the present invention.

[0033] In the first aspect, the present invention provides a method for preparing a laser transfer film. Figure 1 ,include:

[0034] Providing a substrate 2, wherein the substrate 2 comprises a first surface and a second surface arranged opposite to each other;

[0035] A plurality of grooves are formed on the first surface in a direction close to the second surface;

[0036] preparing an anti-reflection layer 3 on the second surface, and curing the anti-reflection layer 3, wherein the anti-reflection layer 3 covers the second surface;

[0037] A hydrophobic and oleophobic layer 1 is prepared on the first surface after the grooves are formed, and the hydrophobic and oleophobic layer 1 is cured, so that the hydrophobic and oleophobic layer 1 covers the first surface and the grooves.

[0038] In other embodiments other than this embodiment, the hydrophobic and oleophobic layer 1 may be formed first, and then the anti-reflection layer 3 may be formed. The order of forming the anti-reflection layer 3 and the hydrophobic and oleophobic layer 1 may be adjusted as needed. In this embodiment, the preparation order of the anti-reflection layer 3 and the hydrophobic and oleophobic layer 1 is not limited.

[0039] Specifically, in this embodiment, a substrate 2 is provided, which has two oppositely arranged surfaces, namely a first surface and a second surface. On the first surface of the substrate 2, a plurality of grooves are provided in the direction toward the second surface. These grooves are for increasing the mechanical strength of the film, improving the transfer effect or adjusting the characteristics of the film. An anti-reflection layer 3 is prepared on the second surface of the substrate 2, the purpose of which is to reduce the reflection of the laser during the transfer process and improve the transfer efficiency. After the preparation is completed, the anti-reflection layer 3 is cured to ensure its stability and durability.

[0040] A hydrophobic and oleophobic layer 1 is prepared on the first surface after the grooves are formed. This layer can increase the repellency of the film to ink or laser, prevent pollution, and improve the transfer quality. Similarly, a curing treatment is required after the preparation is completed.

[0041] Furthermore, the hydrophobic and oleophobic layer 1 is a transparent coating.

[0042] The core of laser transfer technology is to use laser energy to transfer patterns or substances from a transfer film to another surface. If the hydrophobic and oleophobic layer 1 is not transparent, it will block the transmission of the laser, reduce the transfer efficiency or even make the transfer impossible. At the same time, the use of a transparent hydrophobic and oleophobic layer 1 allows the operator or machine vision system to directly observe the surface under the transfer film, which is very important for precise alignment to ensure the accuracy of the transferred pattern. During the transfer process, the transparent layer allows the operator to monitor the effect of the laser in real time and adjust the parameters in time to ensure the transfer quality. The non-transparent layer may decompose or release pollutants under laser irradiation, which will contaminate the transfer surface or affect the transfer quality.

[0043] Furthermore, the groove is formed by a nano-imprinting method, and the groove is in an inverted trapezoidal shape.

[0044] Nanoimprint technology is a high-precision replication technology used to form micro-nanoscale structures. The specific process includes:

[0045] A nanoscale mold (imprint head) having a desired shape is placed on the first surface of substrate 2. Pressure is applied to the mold so that it is pressed into the surface of substrate 2, thereby forming a groove corresponding to the shape of the mold on substrate 2. After the mold is removed, the desired groove structure will be left on the surface of substrate 2.

[0046] The inverted trapezoidal structure can provide better mechanical stability and help to withstand external forces during the transfer process. At the same time, it helps to improve the propagation characteristics of the laser on the film, thereby improving the transfer efficiency.

[0047] Furthermore, before preparing the anti-reflection layer 3 , the method further includes: cleaning the first surface and the second surface of the substrate 2 .

[0048] Furthermore, the sample was washed with deionized water, anhydrous ethanol and petroleum ether in sequence.

[0049] Cleaning can remove pollutants such as dust, grease, fingerprints, and residual chemicals on the surface of the substrate 2, which will affect the adhesion and performance of the anti-reflection layer 3 and the hydrophobic and oleophobic layer 1. At the same time, it can enable the subsequently coated anti-reflection layer 3 to better wet and adhere to the substrate 2. The cleaned surface helps to reduce defects in the film layer, such as bubbles and cracks, thereby improving the overall quality of the product.

[0050] In the present embodiment, deionized water is used to remove soluble inorganic salts, ionic pollutants and most water-soluble impurities on the surface of substrate 2. Substrate 2 is immersed in deionized water, gently scrubbed with a brush, or cleaned with an ultrasonic cleaner, then taken out and rinsed with deionized water. Anhydrous ethanol is used to dissolve and remove grease, wax and other non-polar organic pollutants on the surface of substrate 2. After cleaning with deionized water, substrate 2 is immersed in anhydrous ethanol, and a brush or ultrasonic cleaner can also be used, and then rinsed with anhydrous ethanol. Petroleum ether is a non-polar solvent used to remove hydrophobic pollutants on the surface of substrate 2, such as incompletely dissolved grease and certain resins. After cleaning with anhydrous ethanol, substrate 2 is immersed in petroleum ether for cleaning, then rinsed with petroleum ether and dried.

[0051] After completing the above cleaning steps, the substrate 2 should be thoroughly dried, and nitrogen purging, a dryer or heating methods can be used to ensure that there is no liquid residue on the surface of the substrate 2. Only after the substrate 2 is completely dried can the anti-reflection layer 3 be prepared to prevent moisture or other solvents from affecting the performance of the anti-reflection layer 3.

[0052] Furthermore, the anti-reflection layer 3 or the hydrophobic and oleophobic layer 1 is cured by irradiation with an ultraviolet lamp.

[0053] Furthermore, the irradiation time of the ultraviolet lamp is 3 min-5 min, for example, 3.5 min, 4 min or 4.5 min.

[0054] Specifically, UV curing is a photo-induced curing process in which the photoinitiator decomposes under UV light to produce free radicals, which in turn initiate polymerization of double bonds in the resin or monomer, thereby achieving the curing effect. This curing method has the advantages of being fast, efficient, and environmentally friendly because it does not require high temperatures and does not produce organic solvent volatilization.

[0055] After the anti-reflection layer 3 or the hydrophobic and oleophobic layer 1 is coated, the substrate 2 is placed under the UV lamp. The UV lamp is turned on and the entire coating layer is evenly exposed to light. After irradiation for 3 to 5 minutes, the UV lamp is turned off and the curing effect is checked. If the curing is not complete, the irradiation time or the intensity of the lamp needs to be adjusted.

[0056] In a second aspect, the present invention provides a laser transfer film, please refer to Figure 2 , prepared by the laser transfer film preparation method as described in any one of the above items, comprising:

[0057] A substrate 2, the substrate 2 comprising a first surface and a second surface arranged opposite to each other, the first surface being provided with a plurality of grooves extending toward the second surface;

[0058] A hydrophobic and oleophobic layer 1, wherein the hydrophobic and oleophobic layer 1 is disposed on the first surface and covers the first surface and the first groove;

[0059] The anti-reflection layer 3 is disposed on the second surface and covers the second surface.

[0060] The presence of the anti-reflection layer 3 reduces the loss of laser energy, thereby improving the transfer efficiency. The hydrophobic and oleophobic layer 1 ensures the cleanliness of the film surface during the transfer process, reducing contamination and defects. The groove design increases the mechanical strength of the film, making it more suitable for various transfer processes and applications.

[0061] Furthermore, the thickness of the substrate 2 is 45 μm-75 μm.

[0062] Furthermore, the thickness of the anti-reflection layer 3 is 0.3 μm-0.36 μm.

[0063] Furthermore, the hydrophobic and oleophobic layer 1 has a thickness of 1 μm-2 μm.

[0064] The thickness of the substrate 2 needs to be sufficient to provide the necessary mechanical strength and stability, but also thin enough to maintain flexibility and adapt to the user's specific transfer process. Substrates 2 of different thicknesses will affect the transmission and reflection characteristics of the laser, thereby affecting the transfer effect. Too thick will result in insufficient laser penetration, while too thin will lack sufficient supporting force. In this embodiment, the thickness of the substrate 2 is preferably 50 μm, and the material of the substrate 1 can be selected from PET (polyethylene terephthalate) or PC (polycarbonate).

[0065] The thickness of the anti-reflection layer 3 needs to be precisely controlled to ensure that it can effectively reduce the reflection of the laser while not hindering the transmission of the laser. If the anti-reflection layer 3 is too thin, it cannot fully reduce the reflection, while if it is too thick, it absorbs too much laser energy and reduces the transfer efficiency. In this embodiment, the thickness of the anti-reflection layer 3 is preferably 0.3 μm, and the material of the anti-reflection layer 3 includes but is not limited to MgF2 gel, porous ZrO2 gel, porous nano-SiO2 gel, fluorine-modified polyurethane resin or fluorine-containing methyl methacrylate resin.

[0066] The thickness of the hydrophobic and oleophobic layer 1 needs to be sufficient to provide effective hydrophobic and oleophobic properties, but it should not be too thick so as not to affect other properties of the transfer film, such as flexibility and light transmittance. Appropriate thickness can ensure that ink or other substances will not easily adhere to the surface of the film during the transfer process, keeping the surface of the film clean. In this embodiment, the thickness of the anti-reflection layer 3 is preferably 1.2μm, 1.5μm or 1.7μm, and the hydrophobic and oleophobic layer 1 material includes but is not limited to fluorine-containing polyurethane resin, perfluoropolyether (PFPE) resin, polytetrafluoroethylene, oleophobic modified polyethylene, silica gel, and nano-silicon oxide type fluorine-containing acrylic composite resin.

[0067] The transfer film formed by the above method, please refer to the experimental group data in Table 1 below, and Figure 3 and Figure 4 Schematic diagram under the microscope shown. In Table 1, Jsc is the short-circuit current density of the photovoltaic cell, which can reflect the shielding loss of the grid line. FF is the fill factor of the photovoltaic cell, which can reflect the resistance loss during the current transmission process. It can be seen that the transfer film obtained by the method in the present application has a significantly increased aspect ratio of the grid line, and the Jsc value and FF value generated by it are increased at the same time, which means that the solar cell can generate more current, thereby having a higher power output.

[0068] Table 1

[0069]

[0070] The above specific examples are used to illustrate the present invention, which is only used to help understand the present invention and is not intended to limit the present invention. For those skilled in the art, according to the concept of the present invention, some simple deductions, modifications or substitutions can be made.

Claims

1. A method for preparing a laser transfer film, characterized in that: include: Providing a substrate, the substrate comprising a first surface and a second surface disposed opposite to each other; A plurality of grooves are formed on the first surface in a direction close to the second surface; Preparing an anti-reflection layer on the second surface and curing the anti-reflection layer, wherein the anti-reflection layer covers the second surface; A hydrophobic and oleophobic layer is prepared on the first surface after the grooves are formed, and the hydrophobic and oleophobic layer is solidified, so that the hydrophobic and oleophobic layer covers the first surface and the grooves.

2. The method for preparing a laser transfer film according to claim 1, wherein: The hydrophobic and oleophobic layer is a transparent coating.

3. The method for preparing a laser transfer film according to claim 1, wherein: The groove is formed by a nano-imprinting method and has an inverted trapezoidal shape.

4. The method for preparing a laser transfer film according to claim 1, wherein: Before preparing the anti-reflection layer, the method further includes: cleaning the first surface and the second surface of the substrate.

5. The method for preparing a laser transfer film according to claim 4, characterized in that: The substrate is cleaned with deionized water, anhydrous ethanol and petroleum ether in sequence.

6. The method for preparing a laser transfer film according to claim 1, wherein: The anti-reflection layer or the hydrophobic and oleophobic layer is cured by irradiating with an ultraviolet lamp.

7. The method for preparing a laser transfer film according to claim 6, wherein: The irradiation time of the ultraviolet lamp is 3min-5min.

8. A laser transfer film prepared by the laser transfer film preparation method according to any one of claims 1 to 7, characterized in that: include: A substrate, the substrate comprising a first surface and a second surface arranged opposite to each other, the first surface being provided with a plurality of grooves extending toward the second surface; a hydrophobic and oleophobic layer, the hydrophobic and oleophobic layer being disposed on the first surface and covering the first surface and the first groove; An anti-reflection layer is disposed on the second surface and covers the second surface.

9. The method for preparing a laser transfer film according to claim 8, wherein: The thickness of the substrate is 45 μm-75 μm.

10. The method for preparing a laser transfer film according to claim 8, wherein: The thickness of the anti-reflection layer is 0.3 μm-0.36 μm.

11. The method for preparing a laser transfer film according to claim 8, wherein: The hydrophobic and oleophobic layer has a thickness of 1 μm-2 μm, and the hydrophobic and oleophobic layer is a transparent coating.

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