Texturing cleaning method and solar cell

Abstract

The present invention discloses a texturing cleaning method and a solar cell, comprising the following steps: performing a first texturing treatment on a silicon wafer using a first texturing liquid, and cleaning and removing the first texturing liquid on the surface of the silicon wafer to form a primary texturing structure on the surface of the silicon wafer; performing a second texturing treatment on the silicon wafer using a second texturing liquid, and cleaning and removing the second texturing liquid on the surface of the silicon wafer to form a secondary texturing structure on the surface of the silicon wafer; wherein the formation speed of the primary texturing structure is greater than the formation speed of the secondary texturing structure, the primary texturing structure includes a plurality of first pyramids, the secondary texturing structure includes a plurality of second pyramids, and the plurality of second pyramids are dispersed in the gaps between the plurality of first pyramids. In the texturing cleaning method provided by the present invention, the first texturing treatment and the second texturing treatment are combined to improve the coverage of the pyramids on the silicon wafer.

Description

Technical Field

[0001] The invention relates to the technical field of heterojunction solar cells, and in particular to a texturing and cleaning method and a solar cell. Background Art

[0002] Heterojunction solar cells are silicon solar cells that use a heterojunction structure. In the preparation process of heterojunction solar cells, the silicon wafers are generally required to be texturized and cleaned to form a velvet structure including multiple pyramids on the surface of the silicon wafer, that is, to form a microscopically "uneven" silicon wafer surface to improve the reflectivity of the silicon wafer surface, thereby improving the light conversion efficiency of the heterojunction solar cell. However, in the current texturizing and cleaning process, the texturizing additives cannot be completely evenly attached to the surface of the silicon wafer during texturizing, resulting in low coverage of the formed pyramids. Summary of the invention

[0003] The main purpose of the invention is to provide a texturing and cleaning method and a solar cell, which can improve the coverage of pyramids on the surface of a silicon wafer.

[0004] To achieve the above object, the present invention provides a method for cleaning a velvet, comprising the following steps:

[0005] Performing a first texturing treatment on the silicon wafer using a first texturing liquid, and cleaning and removing the first texturing liquid on the surface of the silicon wafer to form a primary texturing structure on the surface of the silicon wafer, wherein the first texturing liquid includes a first alkali solution and a first texturing additive;

[0006] Performing a second texturing treatment on the silicon wafer using a second texturing liquid, and cleaning and removing the second texturing liquid on the surface of the silicon wafer to form a secondary texturing structure on the surface of the silicon wafer, wherein the second texturing liquid comprises a second alkali solution and a second texturing additive, and the second texturing additive is different from the first texturing additive;

[0007] The formation speed of the primary velvet structure is greater than that of the secondary velvet structure, the primary velvet structure includes a plurality of first pyramids, the secondary velvet structure includes a plurality of second pyramids, and the plurality of second pyramids are dispersed in the gaps between the plurality of first pyramids.

[0008] Optionally, the adhesion of the second texturing additive to the surface of the silicon wafer is greater than the adhesion of the first texturing additive to the surface of the silicon wafer.

[0009] Optionally, the alkali concentration of the first alkali solution is greater than that of the second alkali solution, and the alkali concentration of the first alkali solution is 3-10wt%, and the alkali concentration of the second alkali solution is 0.5-5wt%.

[0010] Optionally, the first alkali solution and the second alkali solution both comprise potassium hydroxide.

[0011] Optionally, the temperature of the first texturing treatment is 75-85° C., the temperature of the second texturing treatment is 50-80° C., and the temperature of the first texturing treatment is higher than the temperature of the second texturing treatment.

[0012] Optionally, the time of the first texturing treatment is 100 to 500 seconds, the time of the second texturing treatment is 200 to 600 seconds, and the time of the first texturing treatment is shorter than the time of the second texturing treatment.

[0013] Optionally, before the step of performing a first texturing treatment on the silicon wafer using the first texturing liquid and cleaning and removing the first texturing liquid on the surface of the silicon wafer, the step further includes:

[0014] Performing a diffusion gettering process on the silicon wafer to form an impurity concentration layer on the surface of the silicon wafer;

[0015] The impurity concentration layer is removed, and the silicon wafer is subjected to surface oxidation treatment.

[0016] The present invention also provides a solar cell, the solar cell comprising a silicon wafer, the silicon wafer being obtained by the above-mentioned texturing and cleaning method;

[0017] The silicon wafer surface has a primary velvet structure and a secondary velvet structure, the primary velvet structure includes a plurality of first pyramids, the secondary velvet structure includes a plurality of second pyramids, and the plurality of second pyramids are dispersed in the gaps between the plurality of first pyramids.

[0018] Optionally, a size of the first pyramid is greater than a size of the second pyramid.

[0019] Optionally, the sizes of the first pyramid and the second pyramid are both in micrometer level.

[0020] In the technical solution of the present invention, a first texturing treatment with a faster formation speed is combined with a second texturing treatment with a slower formation speed. When the formation speed is faster, the first pyramids formed by corrosion are large and there are gaps between them. When the formation speed is slower, the second pyramids formed by corrosion are small but uniformly dense, thereby filling the gaps between the first pyramids. In this way, the combination of the first texturing treatment and the second texturing treatment improves the coverage of the pyramids on the silicon wafer. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] 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 some embodiments of the present invention. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 A schematic flow chart of an embodiment of the texturing and cleaning method proposed by the present invention;

[0023] Figure 2 This is a microstructure diagram of the silicon wafer surface after the first texturing treatment in the present invention;

[0024] Figure 3 This is a microstructure diagram of the silicon wafer surface after the second texturing treatment in the present invention.

[0025] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0026] To make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them.

[0027] It should be noted that, in the embodiments, those without specifying specific conditions are carried out according to normal conditions or conditions recommended by the manufacturer. Those without specifying the manufacturer of reagents or instruments used are conventional products that can be purchased commercially. In addition, the meaning of "and / or" appearing in the full text includes three parallel schemes, and "A and / or B" is taken as an example, including schemes A, B, or A and B that meet the same time. In addition, the technical schemes between the various embodiments can be combined with each other, but must be based on the ability of ordinary technicians in the field to achieve. When the combination of the technical schemes is contradictory or cannot be achieved, it should be considered that the combination of such technical schemes does not exist, and is not within the scope of protection required by the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work, all belong to the scope of protection of the present invention.

[0028] The present invention provides an embodiment of a method for cleaning a velvet, please refer to Figure 1 , including the following steps:

[0029] Step S10, performing a first texturing treatment on the silicon wafer using a first texturing liquid, and cleaning and removing the first texturing liquid on the surface of the silicon wafer to form a primary texturing structure on the surface of the silicon wafer, wherein the first texturing liquid includes a first alkali solution and a first texturing additive.

[0030] The first alkali solution is an aqueous solution of common alkalis such as sodium hydroxide, potassium hydroxide, etc., which etches the silicon wafer when in contact with the silicon wafer. When the silicon wafer has good crystallinity, the etching rates of the hydroxide ions in the first alkali solution along different crystal directions are different, that is, the etching rate is anisotropic, but the difference between the etching rates along different crystal directions is small. The first texturing additive is a mixed organic matter with complex components, which can usually be purchased directly from different suppliers (such as Changzhou Shichuang, Japan Lin Junyao, etc.) according to actual application needs. The first texturing additive can adhere well to the surface of the silicon wafer, slow down the etching rate of each crystal direction, and thus amplify the difference between the etching rates in different crystal directions, which is reflected in the morphology. A square pyramid, that is, a "pyramid" structure, is etched on the surface of the silicon wafer. In this embodiment, the first texturing treatment forms a primary velvet structure on the surface of the silicon wafer. The primary velvet structure includes multiple first pyramids, see Figure 2 , which can improve the reflectivity of the silicon wafer surface.

[0031] Before the first texturing treatment, there may be some unwashed contaminants on the surface of the silicon wafer, such as small particles and organic matter. These contaminants prevent the first texturing additive from adhering to the surface of the silicon wafer, resulting in the failure to form the first pyramid at these locations, or the difference in etching rates between different crystal directions at these locations is not sufficiently amplified, and the size of the pyramid formed is much smaller than the first pyramid, which is not conducive to improving the reflectivity of the silicon wafer surface. Figure 2 As shown in the dashed box, there are gaps between the first pyramids. Of course, other reasons may also form Figure 2 This phenomenon includes fluctuations in texturing conditions and fluctuations in the crystallization properties of the silicon wafer itself.

[0032] In this embodiment, after the first texturing treatment, the first texturing liquid on the surface of the silicon wafer is cleaned and removed, usually using HF+HCL+O3 or KOH+H2O2 solution, to react and remove the first texturing additive remaining on the surface of the silicon wafer after the first texturing treatment. This cleaning process also removes the above-mentioned pollutants attached to the surface of the silicon wafer, so that the gap area where the first pyramid is not formed is exposed. The specific parameters of the cleaning process can be adjusted according to the actual application requirements, and this application does not limit this.

[0033] Step S20, performing a second texturing treatment on the silicon wafer using a second texturing liquid, and cleaning and removing the second texturing liquid on the surface of the silicon wafer to form a secondary texturing structure on the surface of the silicon wafer, wherein the second texturing liquid includes a second alkali solution and a second texturing additive, and the second texturing additive is different from the first texturing additive.

[0034] The second alkali solution is similar to the first alkali solution, and specific parameters such as concentration and temperature can be adjusted according to actual application requirements. Similar to the principle of the first texturing treatment, the second texturing treatment can form a secondary velvet structure on the surface of the silicon wafer, and the secondary velvet structure includes multiple second pyramids. This embodiment adjusts the specific parameters of the first alkali solution and the second alkali solution, and selects a second texturing additive that is different from the first texturing additive, so that the formation speed of the primary velvet structure is greater than the formation speed of the secondary velvet structure, and multiple second pyramids are dispersed in the gaps between multiple first pyramids, such as Figure 3 shown.

[0035] That is to say, after the first velvet structure is formed and the first velvet additive is removed by cleaning, the gap area between the first pyramids is exposed, and then the second velvet treatment is performed. The second velvet additive is attached to the surface of the silicon wafer, amplifying the difference between the etching rates of the hydroxide ions in the second alkaline solution on different crystal directions of silicon, thereby forming multiple second pyramids in the gaps of the first pyramids, such as Figure 3 As shown, the coverage of the pyramids on the surface of the silicon wafer is improved, and the reflectivity of the surface of the silicon wafer is further improved.

[0036] Furthermore, the second texturing treatment is performed after the first texturing additive on the surface of the silicon wafer is cleaned and removed, thereby avoiding mutual interference between different texturing additives, reducing the influence of uncontrollable factors in the texturing process, and ensuring that the expected silicon wafer surface is obtained.

[0037] During this process, the second texturing additive will also cover the first pyramid. This embodiment controls the formation speed of the secondary texturing structure to be lower than the formation speed of the primary texturing structure. While forming the second pyramid, the influence on the already formed first pyramid is minimized as much as possible, thereby further improving the reflectivity of the silicon wafer surface.

[0038] After the secondary velvet structure is formed, the second velvet liquid on the surface of the silicon wafer is further cleaned to remove it for subsequent treatment. Specifically, the same or similar cleaning conditions as those after the first velvet treatment can be used, which can be adjusted according to actual application requirements, and this application does not limit this.

[0039] In some embodiments, the adhesion of the second texturing additive on the surface of the silicon wafer is greater than the adhesion of the first texturing additive on the surface of the silicon wafer. For example, the first texturing additive can be Shichuang TS53V01, and the second texturing additive can be Linchunyao TK81. In this way, the adhesion of the second texturing additive in the gaps of the first pyramids can be ensured, further improving the success rate of forming the second pyramids and improving the efficiency of the second texturing treatment. In the technical solution of the present invention, a first texturing treatment with a faster formation speed and a second texturing treatment with a slower formation speed are combined. When the formation speed is faster, the first pyramids formed by corrosion are large and there are gaps between them. When the formation speed is slower, the second pyramids formed by corrosion are small but uniformly dense, thereby filling the gaps between the first pyramids. In this way, the combination of the first texturing treatment and the second texturing treatment improves the coverage of the pyramids on the silicon wafer.

[0040] In some embodiments, the alkali concentration of the first alkali solution is greater than that of the second alkali solution, and the first texturing treatment has a larger alkali concentration, resulting in a larger difference in corrosion rates between different crystal orientations and a faster formation speed of the first pyramid, while the second texturing treatment has a smaller alkali concentration, resulting in a smaller difference in corrosion rates between different crystal orientations and a slower formation speed of the second pyramid, and different additives are used to improve the quality of the pyramids.

[0041] In some embodiments, the alkali concentration of the first alkali solution is 3-10wt%, such as 3wt%, 5wt%, 6wt% or 10wt%, and the alkali concentration of the second alkali solution is 0.5-5wt%, such as 0.5wt%, 1wt%, 3wt% or 5wt%. Under the premise that the alkali concentration of the first alkali solution is greater than the alkali concentration of the second alkali solution, when the alkali concentration of the first alkali solution is 3-10wt% and the alkali concentration of the second alkali solution is 0.5-5wt%, both the pyramid formation speed of the two texturing treatments can be guaranteed and the morphology quality of the pyramid can be improved.

[0042] In some embodiments, the first alkali solution and the second alkali solution both include potassium hydroxide. Potassium hydroxide provides an alkaline environment for the first alkali solution and the second alkali solution, and potassium hydroxide has a wide source, which is conducive to reducing costs.

[0043] In some embodiments, the temperature of the first texturing treatment is 75-85°C, such as 75°C, 80°C or 85°C, and the temperature of the second texturing treatment is 50-80°C, such as 50°C, 60°C, 65°C, 70°C or 80°C, and the temperature of the first texturing treatment is higher than that of the second texturing treatment. Generally speaking, if the temperature is too high, the pyramid continuity will be poor, and if the temperature is too low, the corrosion will be slow and the texturing cycle will be long. However, the present solution limits the temperature of the first texturing treatment to 75-85°C and the temperature of the second texturing treatment to 50-80°C, on the premise that the temperature of the first texturing treatment is higher than that of the second texturing treatment, thereby ensuring the stability of the difference between the first pyramid formation speed and the second pyramid formation speed.

[0044] In some embodiments, the time of the first texturing treatment is 100 to 500 seconds, such as 100 seconds, 200 seconds, 300 seconds or 500 seconds, and the time of the second texturing treatment is 200 to 600 seconds, such as 200 seconds, 300 seconds, 400 seconds, 500 seconds or 600 seconds, and the time of the first texturing treatment is less than the time of the second texturing treatment. The texturing process requires a certain amount of time, but too long a reaction time will also have an adverse effect on the formed pyramid structure, such as causing the pyramid to disappear. This solution limits the time of the first texturing treatment to 100 to 500 seconds and the time of the second texturing treatment to 300 to 600 seconds, on the premise that the time of the first texturing treatment is less than the time of the second texturing treatment, which helps to ensure that the first pyramid and the second pyramid have a good coverage on the surface of the silicon wafer.

[0045] In some embodiments, before the step of performing a first texturing treatment on the silicon wafer using the first texturing liquid and cleaning and removing the first texturing liquid from the surface of the silicon wafer, the step further includes:

[0046] Step 30, performing a diffusion gettering process on the silicon wafer to form an impurity concentration layer on the surface of the silicon wafer;

[0047] Step 40: remove the impurity concentration layer and perform surface oxidation treatment on the silicon wafer.

[0048] Before the silicon wafer is cleaned by texturing, there are metal impurities in it, which will seriously affect the performance of the silicon wafer after texturing and cleaning. Diffusion gettering is the process of diffusing and enriching these metal impurities on the surface of the silicon wafer. In this scheme, metal impurities are enriched on the surface of the silicon wafer through diffusion gettering to form an impurity concentration layer, which is then removed to effectively remove metal impurities and improve the performance of the silicon wafer after texturing and cleaning; in addition, the hydrophilicity of the silicon wafer surface will be increased after surface oxidation treatment, which is convenient for subsequent texturing.

[0049] In some embodiments, step 30 includes:

[0050] Step 31: Use POCl3 to perform diffusion gettering treatment on the silicon wafer. The temperature condition of the diffusion gettering treatment is 700-1200°C, and the time of the gettering treatment is 10-30 minutes.

[0051] In some embodiments, step 40 includes:

[0052] Step 41, cleaning the silicon wafer with HF+HCl+O3 solution at 15-30° C. for 30-600 seconds to remove the impurity concentration layer, wherein the HF+HCl+O3 solution has a HF concentration of 0.2-3 wt %, a HCl concentration of 0.01-0.1 wt %, and an O3 concentration of 20-80 ppm;

[0053] Step 42: Clean the sixth silicon wafer with a KOH+H2O2 solution at 50-85°C for 30-600s to oxidize the surface of the silicon wafer, wherein the concentration of KOH in the KOH+H2O2 solution is 0.5-3wt%, and the concentration of H2O2 is 1-5wt%.

[0054] In some embodiments, before the step of performing a first texturing treatment on the silicon wafer using the first texturing liquid and cleaning and removing the first texturing liquid from the surface of the silicon wafer, the step further includes:

[0055] Step 50: Clean and remove impurities and organic matter on the surface of the silicon wafer, and then perform rough polishing to remove the damaged layer on the surface of the silicon wafer.

[0056] In some embodiments, step 50 includes:

[0057] Step S51, washing the silicon wafer with HF+HCl+O3 solution at 15-30° C. for 30-600 seconds to remove impurities and organic matter on the surface of the silicon wafer, wherein the concentration of HF in the HF+HCl+O3 solution is 0.2-3wt%, the concentration of HCl is 0.01-0.1wt%, and the concentration of O3 is 20-80ppm;

[0058] Step S52, washing the silicon wafer with a KOH solution at 50-90°C for 30-600s to remove the damaged layer on the surface of the silicon wafer, wherein the concentration of KOH in the KOH solution is 3-20wt%;

[0059] Step S53, pickling the silicon wafer with HF+HCl solution at 20-50° C. for 30-600 s to remove the oxide layer and metal ions on the surface of the silicon wafer, wherein the concentration of HF in the HF+HCl solution is 1-10 wt %, and the concentration of HCl is 0.2-5 wt %;

[0060] Step S54, dehydrating the surface of the silicon wafer in pure water at 20 to 50° C. by slow pulling, and the surface dehydration treatment time is 30 to 600 seconds;

[0061] Step S55: drying the surface of the silicon wafer by hot air drying.

[0062] In some embodiments, after the step of performing a second texturing treatment on the silicon wafer using a second texturing liquid and cleaning and removing the second texturing liquid on the surface of the silicon wafer, the method further includes:

[0063] Step 60 , rounding the first pyramid and the second pyramid on the surface of the silicon wafer, and then cleaning to remove the metal ions and oxide layer on the surface of the silicon wafer.

[0064] In some embodiments, step 60 includes:

[0065] Step S61, cleaning the silicon wafer with HF+HCl+O3 solution at 15-30° C. for 30-600 seconds to round the corners of the first pyramid and the second pyramid, wherein the concentration of HF in the HF+HCl+O3 solution is 0.2-3wt%, the concentration of HCl is 0.01-0.1wt%, and the concentration of O3 is 20-80ppm;

[0066] Step S62, washing the silicon wafer with HCl+H2O2 solution at 50-85°C for 30-600s to remove metal ions on the surface of the silicon wafer, wherein the concentration of HCl in the HCl+H2O2 solution is 1-6wt%, and the concentration of H2O2 is 1-5wt%;

[0067] Step S63, washing the silicon wafer with an HF solution at 20 to 50° C. for 30 to 600 seconds to remove the oxide layer on the surface of the silicon wafer, wherein the concentration of HF in the HF solution is 1 to 10 wt %;

[0068] Step S64, dehydrating the surface of the silicon wafer in pure water at 20 to 50° C. by slow pulling, and the surface dehydration treatment time is 30 to 600 seconds;

[0069] Step S65: Drying the surface of the silicon wafer by hot air.

[0070] Based on the same inventive concept, the present invention also proposes an embodiment of a solar cell, the solar cell includes a silicon wafer, and the silicon wafer is obtained by the above-mentioned texturing and cleaning method; wherein the surface of the silicon wafer has a primary velvet structure and a secondary velvet structure, the primary velvet structure includes a plurality of first pyramids, the secondary velvet structure includes a plurality of second pyramids, and the plurality of second pyramids are dispersed in the gaps between the plurality of first pyramids. Since the solar cell includes all the embodiments of the above-mentioned texturing and cleaning method, it has all the beneficial effects brought by all the embodiments of the above-mentioned texturing and cleaning method, which will not be described one by one here.

[0071] In some embodiments, the size of the first pyramid is larger than that of the second pyramid, that is, the first pyramid produced by the first texturing treatment is larger, and the second pyramid produced by the second texturing treatment is smaller. This can better ensure that multiple second pyramids fill the gaps between multiple first pyramids, and the coverage of the pyramids on the silicon wafer is better.

[0072] In some embodiments, the sizes of the first pyramid and the second pyramid are both in the micron level. The micron-level pyramid is smaller in size, which helps to improve the performance of the silicon wafer.

[0073] The technical solution of the present invention is further described in detail below in conjunction with specific examples and drawings. It should be understood that the following examples are only used to explain the present invention and are not used to limit the present invention. Among them, Comparative Example 1 and Examples 1-5 are obtained by using the steps described in the above embodiments, and the specific process parameters are only changed in the temperature, time, and alkali concentration of the first and second texturing treatments, and the other steps remain the same. The process parameters of Comparative Example 1 and Examples 1-5 are compared as shown in Table 1 below.

[0074] Table 1 Specific process parameters of each embodiment

[0075]

[0076] The properties of the silicon wafers after texturing and cleaning prepared in Examples 1-5 and the silicon wafer after texturing and cleaning prepared in Comparative Example 1 were tested respectively. The results are shown in Table 2.

[0077] Table 2 Properties of silicon wafers after various texturing and cleaning

[0078]

[0079] In Table 2, the surface area ratio is the ratio of the surface area after the pyramid surface structure is formed to the original plane surface area, EFF is the conversion efficiency of the battery made of silicon wafer after texturing and cleaning, I sc is the short-circuit current of the battery made of silicon wafer after texturing and cleaning, V oc is the open circuit voltage of the battery made of silicon wafers after texturing and cleaning, and FF is the fill factor of the battery made of silicon wafers after texturing and cleaning.

[0080] It can be seen from Table 2 that the reflectivity of Examples 1-5 is lower than that of Comparative Example 1, indicating that the silicon wafer pyramid coverage of Examples 1-5 is better, proving that the silicon wafer texturing and cleaning method provided by the present invention improves the coverage of the pyramids on the silicon wafer, thereby optimizing the conversion efficiency and electrical performance.

[0081] The above are only preferred embodiments of the present invention, and do not limit the patent scope of the present invention. For those skilled in the art, the present invention may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the patent protection scope of the present invention.

Claims

1. A method for cleaning a velvet, characterized in that: The following steps are involved: Performing a first texturing treatment on the silicon wafer using a first texturing liquid, and cleaning and removing the first texturing liquid on the surface of the silicon wafer to form a primary texturing structure on the surface of the silicon wafer, wherein the first texturing liquid includes a first alkali solution and a first texturing additive; Performing a second texturing treatment on the silicon wafer using a second texturing liquid, and cleaning and removing the second texturing liquid on the surface of the silicon wafer to form a secondary texturing structure on the surface of the silicon wafer, wherein the second texturing liquid comprises a second alkali solution and a second texturing additive, and the second texturing additive is different from the first texturing additive; The formation speed of the primary velvet structure is greater than the formation speed of the secondary velvet structure, the primary velvet structure includes a plurality of first pyramids, the secondary velvet structure includes a plurality of second pyramids, and the plurality of second pyramids are dispersed in the gaps between the plurality of first pyramids; The adhesion of the second texturing additive to the surface of the silicon wafer is greater than the adhesion of the first texturing additive to the surface of the silicon wafer; The time of the first texturing treatment is 100 to 500 seconds, the time of the second texturing treatment is 200 to 600 seconds, and the time of the first texturing treatment is shorter than the time of the second texturing treatment.

2. The texturing cleaning method according to claim 1, characterized in that: The alkali concentration of the first alkali solution is greater than that of the second alkali solution, and the alkali concentration of the first alkali solution is 3-10 wt %, and the alkali concentration of the second alkali solution is 0.5-5 wt %.

3. The texturing cleaning method according to claim 2, characterized in that: The first alkali solution and the second alkali solution both include potassium hydroxide.

4. The texturing cleaning method according to claim 1, characterized in that: The temperature of the first texturing treatment is 75-85° C., the temperature of the second texturing treatment is 50-80° C., and the temperature of the first texturing treatment is higher than the temperature of the second texturing treatment.

5. The texturing cleaning method according to any one of claims 1 to 4, characterized in that: Before the step of performing a first texturing treatment on the silicon wafer using the first texturing liquid and cleaning and removing the first texturing liquid on the surface of the silicon wafer, the method further includes: Performing a diffusion gettering process on the silicon wafer to form an impurity concentration layer on the surface of the silicon wafer; The impurity concentration layer is removed, and the silicon wafer is subjected to surface oxidation treatment.

6. A solar cell, characterized in that: The solar cell comprises a silicon wafer, and the silicon wafer is obtained by the texturing and cleaning method according to any one of claims 1 to 5; The silicon wafer surface has a primary velvet structure and a secondary velvet structure, the primary velvet structure includes a plurality of first pyramids, the secondary velvet structure includes a plurality of second pyramids, and the plurality of second pyramids are dispersed in the gaps between the plurality of first pyramids.

7. The solar cell according to claim 6, characterized in that: The size of the first pyramid is greater than that of the second pyramid.

8. The solar cell according to claim 7, characterized in that: The sizes of the first pyramid and the second pyramid are both in micrometer level.

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