Laser preparation method and application of metal electrode and solar cell

Abstract

The invention relates to the technical field of metal electrode preparation, and provides a metal electrode laser preparation method and application thereof, and a solar cell. The laser preparation method of the metal electrode comprises the following steps that (1) a substrate is immersed in a transparent or semitransparent metal salt solution, and the depth of the metal salt solution ranges from the millimeter level to the centimeter level; and (2) carrying out laser irradiation on the metal salt solution, so that metal ions in the metal salt solution are reduced into metal elementary substances, and the metal elementary substances are deposited and solidified on the surface of the substrate. The laser preparation method of the metal electrode can realize one-time patterning and metallization, and is simple in process, safe, environment-friendly and suitable for industrial application.

Description

Technical Field

[0001] The invention relates to the technical field of preparing metal electrodes, and in particular to a laser preparation method for metal electrodes and applications thereof, and a solar cell. Background Art

[0002] Solar cells are devices that use the photovoltaic effect to directly convert light energy into electrical energy. In order to fully collect the carriers generated by the photovoltaic effect, metal grid lines are prepared on the front surface of the solar cell, and metal grid lines or entire metal electrodes are prepared on the back surface to form physical positive and negative electrodes that can conduct the current generated by the photovoltaic effect. At present, the conventional preparation methods of metal electrodes in solar cells include: (1) After the solar cell completes the ITO conductive film layer process, a 60-150nm copper seed layer is first plated using PVD equipment, and then a photosensitive material is used to mask the front and back sides, and the electrode pattern is prepared by exposure and development to form a copper seed layer; (2) After the electrode pattern is completed, a chemical electroplating process is used to complete the electroplating of copper or copper plus tin electrodes, and finally the mask layer is removed and the excess copper seed layer is etched back to complete the preparation of the copper electrode.

[0003] However, the process of making the seed layer adopts traditional semiconductor material lithography technology, which requires first preparing the metal seed layer through PVD, and then completing the graphic production through three steps of masking, exposure and development. The process flow is complicated, the production cost is high, and the precision control is difficult. Moreover, the production technology of mass production equipment for the later copper electroplating process has not yet been mastered, and the wastewater has a serious environmental pollution and high treatment cost.

[0004] Therefore, it is of great value to develop a metal electrode preparation method that is simple in process, safe, environmentally friendly, and suitable for industrial application. Summary of the invention

[0005] The purpose of the present invention is to overcome the above problems existing in the prior art and provide a laser preparation method for a metal electrode and its application, and a solar cell, wherein the solar cell comprises a metal electrode prepared by the method. The laser preparation method for the metal electrode can realize one-time patterning and metallization, has a simple process, is safe and environmentally friendly, and is suitable for industrial application.

[0006] In order to achieve the above object, the first aspect of the present invention provides a laser preparation method for a metal electrode, comprising the following steps:

[0007] (1) immersing the substrate in a metal salt solution, wherein the metal salt solution is transparent or translucent and has a depth ranging from millimeters to centimeters;

[0008] (2) The metal salt solution is irradiated with laser light, so that the metal ions in the metal salt solution are reduced to metal elements and deposited and solidified on the surface of the substrate.

[0009] In one example, the method for laser preparation of the metal electrode further includes: forming a target pattern metal electrode on the substrate by moving the laser.

[0010] In one example, the laser includes at least one of a dot laser, a line laser, and a surface laser.

[0011] In one example, the process parameters of the dot laser include: a pulse width of 100 fs - 20 ps, a laser power of 5 W - 30 W, a wavelength of 500 nm - 1030 nm, a pulse frequency of 0.1 - 2 MHz, a pulse mode of 1 - 8 pulse trains, including MHz and GHz pulse trains, and a single pulse energy of 15 - 20 μJ.

[0012] In one example, a mask plate is disposed between the substrate and the light source of the laser.

[0013] In a preferred example, a mask plate is disposed above the metal salt solution.

[0014] In one example, the material of the mask plate includes a metal or a metal alloy.

[0015] In one example, the metal salt solution is selected from at least one of soluble metal salt solutions containing copper, silver, nickel, aluminum, and tin elements.

[0016] In one example, the metal salt solution is selected from at least one of cuprous nitrite solution, copper sulfate solution, copper nitrate solution, silver nitrate solution, nickel nitrate solution, silver nitrate solution, and aluminum chloride solution.

[0017] In one example, the concentration of the metal salt solution is not less than 40%.

[0018] In one example, the metal salt solution is a cuprous nitrite solution.

[0019] In one example, the substrate is a polymer material, an electrolyte material, a semiconductor material, or a conductor material;

[0020] In one example, the substrate is selected from at least one of single crystal silicon, polycrystalline silicon, ceramics, glass, flexible materials, metals, alloys, or metal matrix composites.

[0021] In one example, the metal electrode is a metal electrode in a solar cell, a light emitting diode, microelectronics, or an energy device.

[0022] In one example, the metal electrode is a metal electrode of a solar cell, and the solar cell further includes a silicon substrate and a TCO film.

[0023] The second aspect of the present invention provides a method for preparing a solar cell, including the application of the laser preparation method of the metal electrode described in the first aspect of the present invention in the preparation of a solar cell.

[0024] The third aspect of the present invention provides a solar cell, including a metal electrode, wherein the metal electrode is prepared by the method described in the first aspect of the present invention, or by the method described in the second aspect of the present invention.

[0025] The present invention adopts the above technical solutions and has the following advantages:

[0026] (1) The laser preparation method of the metal electrode provided by the present invention avoids high-cost and multi-process process routes such as photolithography, development, and electroplating; avoids the high pollution and high complexity brought by the copper electroplating process; can achieve one-time patterning and metallization, with simple process, safety, and environmental protection;

[0027] (2) The laser preparation method of the metal electrode provided by the present invention can be mass-produced on a large scale and is more suitable for industrial application;

[0028] (3) The laser preparation method of the metal electrode provided by the present invention can finely control the width and thickness of the metal electrode, making the size of the prepared metal electrode more accurate.

[0029] The endpoints and any values within the processing parameter ranges disclosed herein are obtained based on actual experiments. However, due to differences in processing equipment, generally, they are not completely limited to the precise range or value, and can be extended, thus covering a wider range of parameters. For numerical ranges, the endpoints of each range, between the endpoints of each range and individual point values, and between individual point values can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein. Description of the Drawings

[0030] Figure 1 The figure shows a schematic diagram of preparing a metal electrode by single-point continuous scanning with a dot laser.

[0031] Figure 2 The figure shows a schematic diagram of preparing a metal electrode by line scanning with a line laser.

[0032] Figure 3 The figure shows a schematic diagram of preparing a metal electrode by surface scanning with a surface laser.

[0033] Reference numerals: 1 - vessel; 2 - metal salt solution; 3 - substrate; 4 - laser source; 5 - metal electrode; 6 - mask plate. Detailed Embodiments

[0034] The specific embodiments of the present invention are described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0035] Unless otherwise defined, all scientific and technical terms used in the present invention have the same meanings as commonly understood by one of ordinary skill in the art to which the present invention relates.

[0036] A first aspect of the present invention provides a laser preparation method for a metal electrode, comprising the following steps:

[0037] (1) immersing the substrate in a metal salt solution, wherein the metal salt solution is transparent or translucent and has a depth ranging from millimeters to centimeters;

[0038] (2) The metal salt solution is irradiated with laser light, so that the metal ions in the metal salt solution are reduced to metal elements and solidified and deposited on the surface of the substrate.

[0039] In the present invention, since different metals are selected when preparing different metal electrodes, the specific selection of the metal salt solution is not limited. A soluble metal salt solution can be selected according to actual needs. It can be a single metal salt solution or a combination of two or more different metal salts.

[0040] In the present invention, the metal salt solution is "transparent or translucent" according to the concentration of the metal salt solution. Generally, the metal salt solution is transparent or translucent when it is saturated or unsaturated. The transparent or translucent metal salt solution can allow the laser to pass normally.

[0041] In one example, the "transparent state" refers to a state where the transmittance is ≥ 90%; the "semi-transparent state (or certain transmittance)" refers to a state where the transmittance is between 20% and 90%. In the present invention, the transmittance of the metal salt solution can be tested by spectrophotometer colorimetry.

[0042] In one example, the depth of the metal salt solution is in the range of millimeters to centimeters, which can fully ensure that the laser beam reaches the sample surface for chemical reaction, reduce laser energy loss, and improve the efficiency of preparing metal electrodes.

[0043] Through research, the inventors of the present invention found that by immersing a substrate in a metal salt solution that allows laser light to pass through and directly irradiating it with a laser, metal ions in the metal salt solution can be reduced to metallic elements and deposited on the substrate, and the deposited metal material can be patterned into a metal electrode by utilizing the thermal effect generated by the laser. This method for laser preparation of metal electrodes, on the one hand, can achieve one-time patterning and metallization, with a simple process (without processes such as preparing a seed layer, mask, and exposure), being safe, environmentally friendly, and very suitable for industrial application; on the other hand, by using laser irradiation, metallic elements are only deposited in the patterned area, with no impact on other non-irradiated areas, and the prepared metal electrodes have high dimensional accuracy and can be precisely controlled at the micron scale.

[0044] In the present invention, the method for laser preparation of metal electrodes includes steps (1) and (2), and may also include other operating steps, such as a drying step.

[0045] In order to make the process of the method for laser preparation of metal electrodes simpler and the dimensions of the prepared metal electrodes more precise, one or more of the features can be optimized.

[0046] In one example, the method further includes: forming a target patterned metal electrode on the substrate by moving the laser. For example, when preparing grid line metal electrodes suitable for solar cells, the moving path of the laser is preset to correspond to the pattern of the grid line electrodes. In this way, metallic elements can be deposited on the lines of the target pattern by moving the laser, and finally, the preset patterned grid line metal electrodes can be obtained.

[0047] No specific limitation is imposed on the type of laser irradiation, which can be selected according to the requirements of the prepared metal electrodes. Exemplarily, the laser includes at least one of spot laser, line laser, and surface laser.

[0048] In one example, the process parameters of the spot laser include: pulse width: 100 fs - 20 ps, laser power 5 - 30 W, wavelength 500 nm - 1030 nm (such as 532 nm or 1030 nm), pulse frequency 0.1 MHz - 2 MHz, pulse mode (burst mode) 1 - 8 pulse trains, including MHz and GHz pulse trains, and single pulse energy 15 - 20 μJ (such as 17 μJ).

[0049] Selecting a spot laser can prepare metal electrodes with simple patterning or dot patterning; selecting a line laser can prepare metal electrodes with complex patterning or line patterning; selecting a surface laser can prepare metal electrodes with more complex patterning or higher thickness requirements. The specific process parameters of the spot laser, line laser, and surface laser can be adjusted according to the performance parameters of the prepared metal battery.

[0050] In one embodiment, a mask is disposed between the substrate and the laser light source. The mask can be disposed at any position between the substrate and the laser, for example, it can be immersed in the metal solution, or it can be disposed above the metal solution (not immersed) or on the surface of the metal solution (semi-immersed), and the light source close to the substrate or close to the laser can be freely adjusted.

[0051] In the present invention, the "mask" refers to a light-shielding material with a target graphic (pattern) that can prevent laser penetration, wherein the hollowed-out portion of the graphic allows the laser to penetrate.

[0052] When preparing a patterned metal electrode, adding a mask of the target pattern to the preparation process can improve process efficiency and achieve patterning and metallization at one time.

[0053] In one embodiment, a mask is placed above the metal salt solution. In this way, the mask does not need to be immersed in the metal solution, which can prevent the metal element from being deposited on the mask to block the holes and affect the preparation of the patterned metal electrode, and can also improve the dimensional accuracy of the metal electrode.

[0054] The mask can be freely selected according to the laser wavelength. For example, the material of the mask can be metal or metal alloy, such as metal W, Mo, etc., such as pure metal block or metal film, with a film thickness ranging from nanometer to micrometer level.

[0055] In one example, a laser preparation method for a metal electrode may be any one or more of the following three process schemes:

[0056] i: reference Figure 1 , a substrate 3 is placed in a vessel 1 containing a metal salt solution 2, and then a lens / galvanometer / objective lens is used to focus a spot-shaped laser source 4, which is irradiated on the solution / substrate interface to reduce the metal ions in the metal salt solution into metal elements, so that the metal elements are deposited on the surface of the substrate 3, and the deposited materials are connected and solidified by the thermal effect generated during the processing to prepare a metal electrode 5. Among them, the spot-shaped laser moves in the form of direct writing scanning, which can realize the metal element on the substrate according to the preset circuit graphic processing.

[0057] ii: reference Figure 2, placing the substrate 3 in a metal salt solution (the metal salt solution is omitted), setting a mask 6 of the target pattern between the metal salt solution and the laser light source 4, making the substrate 3 and the mask 6 overlap one-to-one (corresponding in the vertical direction), using the linear laser source 4 to scan back and forth, the laser passes through the hollow part of the mask 6 to reduce the metal ions in the metal salt solution into metal elements, so that the metal elements are deposited on the surface of the substrate, and the target pattern is achieved at one time, and the metal electrode 5 is prepared. The metal ions that can be reduced in one scan are limited, and linear laser reciprocating scanning can be used until the required line thickness is reached and a patterned electrode is formed.

[0058] iii: Reference Figure 3 , place the substrate 3 in a metal salt solution (the metal salt solution is omitted), set a mask 6 of a target pattern between the metal salt solution and the laser light source 4, use a planar laser 4 to overlap the substrate 3 and the mask 6 in a one-to-one correspondence (corresponding in the vertical direction), irradiate the metal salt solution by controlling the energy and switching frequency of the planar laser, and the laser passes through the hollow part of the mask 6 to reduce the metal ions in the metal solution into a metal element, so that the metal is deposited on the surface of the substrate and forms a pattern, thereby preparing a metal electrode 5.

[0059] In one example, the metal salt solution is selected from at least one of soluble metal salt solutions containing copper, silver, nickel, aluminum, and tin elements.

[0060] In one example, the metal salt solution is selected from at least one of a copper nitrite solution, a copper sulfate solution, a copper nitrate solution, a silver nitrate solution, a nickel nitrate solution, a silver nitrate solution and an aluminum chloride solution.

[0061] In one example, the metal salt solution is a copper nitrite solution.

[0062] By limiting and optimizing the types of metal salt solutions and selecting several metal salt solutions with good use effects in the art, the preparation method can be optimized, making the preparation process simpler and more conducive to achieving one-time patterning and metallization.

[0063] In one example, the concentration of the metal salt solution is not less than 40%, for example, 40%, 50%, 60%, 70%, 80%, 90%, 100% (saturated state of metal salt dissolution).

[0064] In one example, the metal salt solution is a mixture of a saturated copper nitrite solution and a C1-C6 low-carbon alcohol (such as methanol, ethanol, and propanol); the mixing ratio of the two is not limited and can be reasonably adjusted according to the performance of the prepared metal electrode. Exemplarily, the mass ratio of the saturated copper nitrite solution to the C1-C6 low-carbon alcohol can be 1:(0.5-2).

[0065] In one example, the metal salt solution is a mixture of a saturated copper nitrite solution and ethylene glycol, and the mass ratio of the two is 1:1.

[0066] In one example, the concentration of the copper nitrite solution is 80%-100%.

[0067] The film formation rate of the metal electrode is closely related to the concentration of the metal salt solution. It is preferable to keep the concentration of the metal salt solution within a suitable range to avoid the influence of too low concentration on the formation and deposition rate of the metal element and further shorten the process time.

[0068] In one example, the substrate is a polymer material, an electrolyte material, a semiconductor material or a conductor material. The specific type can be selected according to different application fields. For example, when preparing the metal electrode of a solar cell, the substrate can be single crystal silicon or polycrystalline silicon.

[0069] In one example, the substrate is selected from at least one of single crystal silicon, polycrystalline silicon, ceramics, glass, flexible materials, metals (including various metal alloys) and metal matrix composites.

[0070] Exemplarily, the metal electrode can be the metal electrode in a solar cell, a light emitting diode, microelectronics or an energy device, or can also be a battery or an instrument device in other technical fields. As long as it contains the metal electrode prepared by the method proposed by the present invention, it is within the protection scope of the present invention.

[0071] In one example, the metal electrode is the metal electrode of a solar cell, and the solar cell further includes a silicon substrate and a TCO film (Transparent Conductive Oxide, abbreviated as TCO).

[0072] In one example, the silicon substrate can be single crystal silicon or polycrystalline silicon.

[0073] In one example, the TCO film can be an ITO film (Indium-Tin oxide transparent conductive, abbreviated as ITO), and also includes AZO, FTO, etc.

[0074] The present invention also provides a method for preparing a metal electrode of a solar cell. The solar cell includes a cell sheet composed of a silicon substrate and a TCO film, and includes the following steps:

[0075] (1) Immerse the cell sheet in a metal salt solution, and the metal salt solution is transparent or semi-transparent;

[0076] (2) Perform laser irradiation on the cell sheet so that metal ions in the metal salt solution are reduced to metal elements and deposited on the surface of the cell sheet.

[0077] The metal electrodes of solar cells are usually grid-shaped grid electrodes, that is, patterned electrodes. Using the preparation method of the present invention, one-time patterning and metallization can be achieved, and the metal electrodes of solar cells can be prepared quickly and simply.

[0078] In the present invention, the energy focus of the laser is on the surface of the silicon substrate, and the ITO film on the surface of the silicon substrate has a certain processing ability, which can improve the adhesion of the metal electrode on the surface of the ITO film.

[0079] In one example, a method for preparing a metal electrode of a solar cell can be any one or more of the following three process schemes:

[0080] Scheme 1: Place the silicon substrate after ITO coating in a copper salt solution containing Cu ions, and then irradiate it with spot-shaped laser light to reduce the Cu ions in the copper salt solution to Cu elemental nanomaterials. Use the thermal effect generated by the laser to deposit and connect the Cu elemental nanomaterials on the surface of the silicon substrate. Among them, the spot-shaped laser moves in a direct writing and scanning form, and the line patterning of Cu nanomaterials on the silicon substrate can be realized synchronously.

[0081] Scheme 2: Place the silicon substrate after ITO coating in a copper salt solution containing Cu ions, and set a mask template of the target pattern between the copper salt solution and the laser light source, so that the substrate and the mask template are in one-to-one correspondence in an overlapping manner (corresponding in the vertical direction). Use linear laser to scan back and forth. The laser passes through the hollowed-out part of the mask template to reduce the Cu ions in the copper salt solution to Cu elemental nanomaterials. Use the thermal effect generated by the laser to deposit and connect the Cu elemental nanomaterials on the surface of the silicon substrate, and achieve the target pattern at one time. The amount of Cu ions that can be reduced by one scan is limited, and linear laser can be used to scan back and forth until the required line thickness is reached and a patterned electrode is formed.

[0082] Scheme 3: Place the silicon substrate after ITO coating in a copper salt solution containing Cu ions, and set a mask template of the target pattern between the copper salt solution and the laser light source. Use planar laser to make it in one-to-one correspondence with the silicon substrate / mask template in an overlapping manner (corresponding in the vertical direction). By controlling the energy and switching frequency of the planar laser, irradiate the copper salt solution. The laser passes through the hollowed-out part of the mask template to reduce the Cu ions in the copper salt solution to Cu elemental nanomaterials. Use the thermal effect generated by the laser to deposit and connect the Cu elemental nanomaterials on the surface of the silicon wafer and form a pattern.

[0083] In the above Scheme 1, the width of the metal electrode can be adjusted by controlling the size of the laser spot and the power density of the laser.

[0084] In the above-mentioned schemes 2 and 3, the laser is in a focused or defocused state (the power density of the laser light source on the ITO film is the maximum, and the spot is the minimum at the focused position). As the electrode is generated, the defocused regional thermal effect is gradually used to induce material deposition and connection, so that the patterned area on the ITO film corresponding to the mask plate can grow in the thickness direction to form a patterned Cu electrode with uniform texture.

[0085] In the above-mentioned schemes 2 and 3, the position of the mask is designed to be highly adjustable, so that the width of the laser projected on the silicon wafer can be adjusted by adjusting the height position of the mask, and finally the width of the deposited patterned Cu electrode can be adjusted. The laser is usually irradiated vertically, but there will be slight scattering when the laser moves horizontally or obliquely, which will cause a slight change in the projection width, and then fine-tune the width of the patterned metal electrode. Usually, the fine-tuning distance change is less than 1 micron.

[0086] In the above-mentioned schemes 2 and 3, the mask is set far away from the silicon substrate, and it is preferred that the mask is not immersed in the metal salt solution. In this way, the laser energy is not absorbed by the mask, and the Cu element cannot adhere to the mask to cause hole blockage, thereby ensuring the smooth progress of the electrode preparation process and not affecting the dimensional accuracy of the electrode.

[0087] In the above-mentioned solutions 1, 2 and 3, the thickness of the metal electrode can be precisely controlled by controlling the number of laser scans, so that the size of the prepared metal electrode can be more precise.

[0088] In one example, the thickness of the metal electrode is 5-15 μm.

[0089] In one example, the width of the metal electrode is 5-100 μm.

[0090] The second aspect of the present invention provides the use of the laser preparation method of the metal electrode described in the first aspect of the present invention in the preparation of a solar cell. Except for the preparation of the metal electrode, the remaining methods or processes for preparing the solar cell can be carried out in a conventional manner in the art. The present invention provides a new means for preparing a solar cell (at least a new means for preparing a metal electrode).

[0091] A third aspect of the present invention provides a solar cell, comprising a metal electrode, wherein the metal electrode is prepared by the method described in the first aspect of the present invention.

[0092] In one example, the solar cell is a silicon solar cell, which can be a monocrystalline silicon solar cell, a polycrystalline silicon thin film solar cell, an amorphous silicon thin film solar cell, or other types of solar cells. As long as the metal electrode of the solar cell is obtained by the preparation method provided by the present invention, it is within the protection scope of the present invention.

[0093] Next, in combination with the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0094] The materials, reagents, etc. used in the following embodiments can be obtained from commercial channels without special instructions.

[0095] The present invention will be described in detail below with specific embodiments, and these embodiments are for understanding rather than limiting the present invention.

[0096] Example A: Preparation of copper electrodes by single-point continuous scanning of dot-shaped laser

[0097] Example A1

[0098] A method for preparing a metal electrode of a solar cell includes the following steps:

[0099] (1) Place the silicon wafer after ITO coating in a vessel containing a metal salt solution, and the metal salt solution is a mixed solution prepared by mixing saturated copper nitrite solution and ethylene glycol in a mass ratio of 1:1;

[0100] (2) Use dot-shaped laser to perform single-line continuous scanning on the copper nitrite solution, and induce the reduction of Cu ions in the copper nitrite solution to elemental Cu;

[0101] Among them, the parameters of the dot-shaped laser are set as follows: power 17w, wavelength 1030nm, pulse frequency 2MHz, single-pulse energy 17μJ, defocus amount 2mm;

[0102] (3) The dot-shaped laser moves continuously to generate a continuous patterned Cu electrode.

[0103] Example A2

[0104] Basically the same as Example A1, the difference is that when the defocus amount is 0, while obtaining the electrode, the laser has a certain destructive ablation effect on the silicon wafer, which can make the deposited copper and the silicon wafer combine better.

[0105] Example B: Preparation of copper electrodes by line scanning of linear laser

[0106] A method for preparing a metal electrode of a solar cell includes the following steps:

[0107] (1) Place the silicon wafer after ITO coating in a vessel containing a metal salt solution, and the metal salt solution is a mixed solution prepared by mixing saturated copper nitrite solution and ethylene glycol in a mass ratio of 1:1;

[0108] (2) A mask plate is arranged above the cuprous nitrite solution. The mask plate is a light-shielding plate with a patterned hollow structure prepared from a metal material;

[0109] (3) Use a linear laser to reciprocally scan the cuprous nitrite solution to induce the reduction of Cu ions in the cuprous nitrite solution into elemental Cu;

[0110] (3) The linear laser passes through the mask plate for scanning, and the target pattern can be realized on the silicon wafer at one time. The amount of Cu ions that can be reduced by one scan is limited. The linear laser is used for reciprocating scanning until the required line thickness is reached, and finally a continuous patterned Cu electrode is generated.

[0111] Example C: Use a planar laser for planar scanning to prepare a copper electrode

[0112] A method for preparing a metal electrode of a solar cell includes the following steps:

[0113] (1) Place the silicon wafer after ITO coating in a container containing a metal salt solution. The metal salt solution is a mixed solution prepared by mixing saturated cuprous nitrite solution and ethylene glycol in a mass ratio of 1:1;

[0114] (2) A mask plate is arranged above the cuprous nitrite solution. The mask plate is a light-shielding plate with a patterned hollow structure prepared from a metal material;

[0115] (3) Use a planar laser to reciprocally scan the cuprous nitrite solution to induce the reduction of Cu ions in the cuprous nitrite solution into elemental Cu;

[0116] (3) The planar laser passes through the mask plate and reciprocally scans and irradiates at a certain time frequency, and the target pattern can be realized on the silicon wafer at one time. The amount of Cu ions that can be reduced by one scan is limited. The linear laser is used for reciprocating scanning until the required line thickness is reached, and finally a continuous patterned Cu electrode is generated.

[0117] The methods for preparing the metal electrodes provided in the above embodiments avoid high-cost and multi-process process routes such as photolithography, development, and electroplating; they also avoid the highly polluting and difficult processes of copper electroplating; they can all achieve one-time patterning and metallization, with simple processes, safety, environmental protection, scalability in mass production, and suitability for industrial applications.

[0118] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for laser preparation of a metal electrode, characterized in that, It includes the following steps: (1) Immerse the substrate in a metal salt solution, the metal salt solution being transparent or semi-transparent, and the depth of the metal salt solution being in the millimeter to centimeter range; (2) Irradiate the metal salt solution with laser light, causing the metal ions in the metal salt solution to be reduced to metallic elements and deposited and solidified on the surface of the substrate.

2. The method according to claim 1, wherein, The method further includes: forming a target pattern metal electrode on the substrate by moving the laser.

3. The method according to claim 2, wherein, The laser includes at least one of a dot laser, a line laser, and a surface laser; Preferably, the process parameters of the dot laser include: a pulse width of 100 fs - 20 ps, a laser power of 5 W - 30 W, a wavelength of 500 nm - 1030 nm, a pulse frequency of 0.1 MHz - 2 MHz, a pulse mode of 1 - 8 pulse trains, including MHz and GHz pulse trains, and a single pulse energy of 15 - 20 μJ.

4. The method according to claim 1, wherein The method further includes: arranging a mask between the substrate and the light source of the laser, preferably arranging the mask above the metal salt solution; Preferably, the material of the mask includes a metal or a metal alloy.

5. The method according to any one of claims 1-4, wherein, The metal salt solution is selected from at least one of soluble metal salt solutions containing copper, silver, nickel, aluminum, and tin elements; Preferably, the metal salt solution is selected from at least one of cuprous nitrite solution, copper sulfate solution, copper nitrate solution, silver nitrate solution, nickel nitrate solution, silver nitrate solution, and aluminum chloride solution.

6. The method according to any one of claims 1-4, wherein, The concentration of the metal salt solution is not less than 40%; Preferably, the metal salt solution is a cuprous nitrite solution.

7. The method according to any one of claims 1 to 4, wherein, The substrate is a polymer material, an electrolyte material, a semiconductor material, or a conductor material; Preferably, the substrate is selected from at least one of single crystal silicon, polycrystalline silicon, ceramics, glass, flexible materials, metals, alloys, or metal matrix composites.

8. The method according to any one of claims 1-4, wherein, The metal electrode is a metal electrode in a solar cell, a light-emitting diode, microelectronics, or an energy device; And / or, the metal electrode is a metal electrode of a solar cell, and the solar cell further includes a silicon substrate and a TCO film.

9. Application of the laser preparation method of the metal electrode according to any one of claims 1 - 8 in the preparation of a solar cell.

10. A solar cell, comprising a metal electrode, characterized in that, The metal electrode is prepared by the method according to any one of claims 1 - 8.

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