A two-step texturizing additive, a two-step texturizing solution, a preparation method and use thereof

Abstract

The application provides a two-step texturing additive, a two-step texturing solution, a preparation method and an application, the two-step texturing additive comprising a first texturing agent and a second texturing agent; the first texturing agent comprises the following components in a weight ratio: a texturing agent 0.1-2 parts; a first surfactant 0.01-0.5 parts; a first etching catalyst 0.5-5 parts; a first inorganic alkali 1-5 parts; and first deionized water 50-90 parts; and the second texturing agent comprises the following components in a weight ratio: a second surfactant 0.01-2 parts; a second etching catalyst 1-5 parts; a second inorganic alkali 1-5 parts; and second deionized water 40-80 parts. The two-step texturing additive is suitable for the field of high-efficiency solar cells, has the advantages of green environmental protection, high texturing efficiency, stability and long service life, and can prepare a submicron-level texturing structure with low reflectivity and high density.

Description

Technical Field

[0001] This invention relates to monocrystalline silicon surface treatment technology, and more particularly to a two-step texturing additive, a two-step texturing solution, a preparation method, and its uses. Background Technology

[0002] Perovskite thin films are typically deposited using solution spin-coating. To achieve good contact between crystalline silicon and perovskite, a relatively flat surface on the Si substrate is required. However, this planar structure leads to significant photocurrent loss due to light reflection. Some long-wavelength light cannot be absorbed and utilized by the bottom silicon cell, resulting in a large current mismatch between the two sub-cells, ultimately limiting the current density of the stacked device. To increase the short-circuit current of the crystalline silicon / perovskite stacked cell, the silicon substrate retains a textured structure. Currently, pyramidal textured surfaces with good light-trapping effects are typically between 1.5-3 μm in size. However, due to the limited thickness of solution-processed perovskite films (≈1 μm), micron-sized pyramidal textures are not well-suited for perovskite solution processing. To ensure that the perovskite uniformly covers all micron-sized surface textures, the perovskite thickness needs to be increased to the micron level.

[0003] However, increased film thickness leads to greater stress in the crystallization process, inducing crack formation. Simultaneously, increased precursor solution concentration results in increased viscosity, causing poor contact at the Si pyramid valleys, which severely hinders further improvements in the efficiency of crystalline silicon / perovskite tandem solar cells.

[0004] To better meet the evolving needs of crystalline silicon / perovskite tandem solar cell technology, the textured surface size of crystalline silicon cells needs to be controlled within the submicron or nanometer range. Reducing the textured surface size typically comes at the cost of sacrificing reflection. To achieve optimal light-trapping capability at submicron or nanometer-scale textured surface sizes, the incident light must exhibit multiple scattering and gradient refraction effects within the submicron or nanometer-scale textured structure. This requires higher uniformity, a larger aspect ratio, and more light-trapping microstructures within the submicron or nanometer-scale textured surface structure.

[0005] Therefore, how to develop a submicron textured surface structure that combines low reflection and high density has become one of the urgent problems to be solved in the current crystalline silicon solar cell technology. Summary of the Invention

[0006] The purpose of this invention is to address the problem that traditional texturing methods cannot simultaneously achieve a high-density submicron textured surface structure and low reflectivity. This invention proposes a two-step texturing additive suitable for the field of high-efficiency solar cells. This additive offers advantages such as being environmentally friendly, highly efficient, stable, and having a long lifespan. It can produce solar cells that combine low reflectivity (reflectance ≤ 9.0%) and high density (texture density ≥ 250,000 / mm²). 2The submicron-scale velvety structure.

[0007] It should be noted that, in this invention, unless otherwise specified, the specific meaning of "comprising" in relation to composition and description includes both open-ended meanings such as "comprising," "including," etc., and closed-ended meanings such as "composed of," "consisting of," etc., and similar meanings.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is: a two-step texturing additive, comprising a first texturing agent and a second texturing agent;

[0009] The first texturing agent comprises the following components by weight:

[0010]

[0011] The second texturing agent comprises the following components by weight:

[0012]

[0013] Furthermore, the texturing agent is a natural low-viscosity polysaccharide polymer.

[0014] Furthermore, the viscosity of the fabricating agent is ≤200 mPa·s.

[0015] Furthermore, the down-forming agent is one or more of guar gum, okra gum, flaxseed gum, acacia gum, and peach gum.

[0016] Furthermore, the texturing agent is preferably acacia resin.

[0017] Furthermore, the amount of the down-forming agent is 0.5-1 part.

[0018] Furthermore, the first surfactant is a gemini-type anionic polyether-modified silicone surfactant, the structure of which is shown in Formula I:

[0019]

[0020] In Formula I, m is the addition number of the -(CH3)2SiO group, and its value is an integer from 0 to 10;

[0021] n is the number of addition groups of EO, which is an integer between 5 and 100;

[0022] R is a sulfonic acid group or a carboxyl group.

[0023] Furthermore, m is an integer from 0 to 2, for example, m is 0, 1, or 2.

[0024] Furthermore, n is an integer between 10 and 30, for example, n is 10, 15, 20, 25, 30, etc.

[0025] Further, the first surfactant is one or more of the following: Gemini anionic polyether modified organosilicon sulfonic acid, Gemini anionic polyether modified organosilicon carboxylic acid, Gemini anionic polyether modified organosilicon sulfonate, and Gemini anionic polyether modified organosilicon carboxylic acid salt.

[0026] Furthermore, the first surfactant is preferably a gemini anionic polyether modified organosilicon sulfonic acid and / or a gemini anionic polyether modified organosilicon sulfonate.

[0027] Furthermore, the first surfactant is 0.1-0.2 parts.

[0028] Furthermore, the first etching catalyst is a phosphonic acid derivative.

[0029] Furthermore, the first etching catalyst is one or more of dimethylphosphonic acid, nonylphosphonic acid, diethylphosphonic acid, 2-hydroxyethylphosphonic acid, ibandronic acid, neridonic acid, risedronic acid, and zoledronic acid.

[0030] Furthermore, the first etching catalyst is preferably a nitrogen-containing bisphosphonic acid and / or a hydroxyl-containing phosphonic acid.

[0031] Furthermore, the nitrogen-containing bisphosphonic acid is one or more of risedronic acid, zoledronic acid, neridronic acid, and ibandronic acid.

[0032] Furthermore, the hydroxyl-containing phosphonic acid is one or more of dimethylphosphonic acid, nonylphosphonic acid, diethylphosphonic acid, and 2-hydroxyethylphosphonic acid.

[0033] Furthermore, the first etching catalyst is more preferably a nitrogen-containing bisphosphonic acid and a hydroxyl-containing phosphonic acid in a mass ratio of 1-9:1.

[0034] Furthermore, the first etching catalyst is preferably zoledronic acid and 2-hydroxyethyl phosphoric acid.

[0035] Furthermore, the first etching catalyst is more preferably zoledronic acid and 2-hydroxyethyl phosphoric acid in a mass ratio of 1-9:1.

[0036] Furthermore, the first etching catalyst is 1-2 parts.

[0037] Furthermore, the first inorganic base is NaOH and / or KOH.

[0038] Furthermore, the first inorganic base is preferably NaOH.

[0039] Furthermore, the first inorganic base is 1-3 parts.

[0040] Furthermore, the first deionized water is 70-80 parts.

[0041] Furthermore, the second surfactant is a nonionic surfactant or an amphoteric surfactant.

[0042] Furthermore, the second surfactant is one or more of fatty alcohol polyoxyethylene ether AEO-9, cocoyl glucoside, fatty acid diethanolamide, octylphenol polyoxyethylene ether, nonylphenol polyoxyethylene ether, cocamidopropyl betaine, and cocamidopropyl hydroxysulfonate betaine.

[0043] Furthermore, the second surfactant is a betaine-type zwitterionic surfactant.

[0044] Furthermore, the second surfactant is preferably cocamidopropyl betaine and / or cocamidopropyl hydroxysulfonate betaine.

[0045] Furthermore, the second surfactant is 0.3-0.5 parts.

[0046] Furthermore, in this invention, the second etching catalyst may be the same as or different from the first etching catalyst. For example, the second etching catalyst may be the same as the first etching catalyst, and the second etching catalyst may be one or more of phosphonic acid and its derivatives.

[0047] Furthermore, the second etching catalyst is one or more of dimethylphosphonic acid, nonylphosphonic acid, diethylphosphonic acid, hydroxyethyl phosphate, ibandronic acid, neridonic acid, risedronic acid, and zoledronic acid.

[0048] Furthermore, the second etching catalyst is preferably zoledronic acid and 2-hydroxyethyl phosphoric acid.

[0049] Furthermore, the second etching catalyst is more preferably zoledronic acid and 2-hydroxyethyl phosphoric acid in a mass ratio of 1-9:1.

[0050] Furthermore, the second etching catalyst is 1-2 parts.

[0051] Furthermore, the second inorganic base is NaOH and / or KOH.

[0052] Furthermore, the second inorganic base is preferably KOH.

[0053] Furthermore, the second inorganic base is 1-3 parts.

[0054] Furthermore, the second deionized water is preferably 50-80 parts.

[0055] Another object of the present invention discloses a two-step method for preparing a flocking additive, comprising the following steps:

[0056] Preparation of the first texturing agent: At room temperature, add all components except the first deionized water to 1 / 3-1 / 2 of the first deionized water, stir until all components are completely mixed, then add the remaining first deionized water, and continue stirring to obtain the first texturing agent.

[0057] Preparation of the second texturing agent: At room temperature, add all components except the second deionized water to 1 / 3 to 1 / 2 of the second deionized water, stir until all components are completely mixed, then add the remaining second deionized water and continue stirring to obtain the second texturing agent.

[0058] Another objective of this invention is to disclose the application of a two-step texturing additive in the field of wet etching texturing of single-crystal silicon.

[0059] Another object of the present invention discloses a two-step texturing solution, comprising a first texturing solution and a second texturing solution, wherein the first texturing solution comprises a first texturing agent, an alkali, and deionized water in the two-step texturing additive, and the second texturing solution comprises a second texturing agent, an alkali, and deionized water.

[0060] Furthermore, the first texturing solution comprises a first texturing agent, alkali, and deionized water in a mass ratio of 0.1-1:4-6:80-100.

[0061] Furthermore, the first texturing solution comprises a first texturing agent, alkali, and deionized water in a preferred mass ratio of 0.5-0.6:5:80-100.

[0062] Furthermore, the base is NaOH and / or KOH.

[0063] Furthermore, the second texturing solution comprises a second texturing agent, alkali, and deionized water in a mass ratio of 0.1-1:2-3:80-100.

[0064] Furthermore, the second texturing solution comprises a second texturing agent, alkali, and deionized water in a preferred mass ratio of 0.5-0.6:2.5:80-100.

[0065] Furthermore, the base is NaOH and / or KOH.

[0066] Another object of the present invention discloses a method for preparing a two-step texturing solution, comprising the following steps:

[0067] Preparation of the first texturing solution: The first texturing agent and alkali are added to deionized water at 80-85℃ and stirred and mixed evenly to prepare the first texturing solution;

[0068] Preparation of the second texturing solution: The second texturing agent and alkali are added to deionized water at 65-70℃ and stirred until homogeneous to prepare the second texturing solution.

[0069] Another objective of this invention is to disclose the application of a two-step texturing solution in the field of wet etching texturing of single-crystal silicon.

[0070] Furthermore, the single-crystal silicon wafer is wet-etched and texturized using the aforementioned two-step texturing solution, comprising the following steps:

[0071] S1: Place the monocrystalline silicon wafer into the first texturing solution to perform the first texturing step;

[0072] S2: Rinse the monocrystalline silicon wafer after the first texturing step with deionized water, and then put the monocrystalline silicon wafer into the second texturing solution for the second texturing step;

[0073] S3: Rinse the front and back sides of the texturized monocrystalline silicon wafer with deionized water and ethanol respectively, and dry the monocrystalline silicon wafer in an N2 atmosphere.

[0074] This invention employs a two-step texturing process: first, a dense and uniform high-density pyramid shape is formed on the silicon wafer surface using a first texturing solution, and then a second micro-etching is performed using a second texturing solution to obtain a textured surface structure that combines low reflection, high density, and submicron level.

[0075] The two-step texturing additive, two-step texturing solution, their preparation method, and applications of the present invention have the following advantages compared with the prior art:

[0076] 1) The first surfactant in the first texturing agent of this invention, while possessing both good wetting and defoaming effects, achieves the preparation of a uniform, high aspect ratio texturing surface through charge gradient interface regulation. Preferably, when R is a sulfonic acid group, the "dumbbell-shaped" structure of the gemini sulfonate surfactant is anchored to defect sites on the silicon surface through the disulfonic acid group, and its polyether chains form a gradient charge layer at the liquid / solid interface: a high charge density region near the silicon surface, gradually transitioning to a neutral region outwards. This gradient electric field guides OH... - Ions accumulate at the bottom of the pyramid, causing the etching rate at the bottom to be significantly higher than that at the peak, thus achieving self-optimization of the aspect ratio of the textured surface.

[0077] 2) The preferred nitrogen-containing bisphosphonic acid and hydroxyl-containing phosphonic acid catalyst in the first texturing agent of this invention achieve a stable etching rate through a chelation-dissociation dynamic equilibrium and thermal stability synergistic mechanism, thereby avoiding texturing surface collapse caused by local over-etching. The nitrogen-containing bisphosphonic acid forms a stable multi-ring chelate with the ≡Si-O- on the silicon surface through a bidentate coordination mode. In an alkaline environment, the activation energy of the etching reaction, which involves the breaking of the PO-Si bond in the chelate, is reduced, thus achieving rapid etching. Simultaneously, the nitrogen-containing bisphosphonic acid can undergo a protonation-deprotonation cycle at high temperatures, dynamically releasing H₂. + To neutralize local OH -Concentration is controlled to avoid excessive etching and surface collapse due to excessively high local concentration, ensuring the uniformity and integrity of submicron structure dimensions; a three-dimensional hydrogen bond network constructed from 2-hydroxyethyl phosphate and zoledronic acid is used to stabilize the ring-opening rate of zoledronic acid, thereby effectively extending its service life.

[0078] 3) In the two-step texturing additive system of the present invention, the first surfactant in the first texturing agent constructs a strong electronegativity on the initially formed pyramid surface. Utilizing the principle of charge compatibility, it synergistically enhances the effect with the nonionic surfactant or amphoteric surfactant in the second texturing agent. While avoiding charge repulsion and strong adsorption, it achieves the function of "vertex protection + crystal surface micro-etching", ultimately realizing precise graded control of the dynamics of the texturing liquid. Thus, under a wider process window, a submicron-level texturing structure with excellent light-trapping properties is obtained.

[0079] Using the two-step pile-forming additive of this invention, the pile surface density of the resulting pile structure is >250,000 / mm². 2 The textured surface height is close to 1 μm, and the reflectivity can be controlled between 8.5% and 9.0%. Therefore, the two-step high-efficiency texturing additive system proposed in this invention achieves the preparation of low-reflectivity submicron-level textured structures under the premise of high textured surface density, and has very good application prospects and large-scale industrialization potential in the field of monocrystalline silicon texturing. Attached Figure Description

[0080] Figure 1 This is a 15,000x magnified SEM image of the surface of the piled surface after pile formation using the two-step pile-forming solution of Example 9;

[0081] Figure 2 This is a 15,000x magnified SEM image of the surface of the piled surface after using the two-step piled solution from Comparative Example 6. Detailed Implementation

[0082] The present invention will be further described below with reference to embodiments. The description of the technical features described below is based on representative embodiments and specific examples of the present invention, but the present invention is not limited to these embodiments and specific examples. It should be noted that:

[0083] Unless otherwise stated, all units used in this specification are international standard units, and all numerical values ​​and ranges appearing in this invention should be understood to include systematic errors that are unavoidable in industrial production.

[0084] In this specification, the range of values ​​referred to as "value A to value B" refers to the range including the endpoint values ​​A and B.

[0085] In this specification, the numerical range indicated by "above" or "below" refers to the numerical range that includes the stated number.

[0086] In this specification, the word "may" has two meanings: to perform a certain process and not to perform a certain process.

[0087] In this specification, the terms "optional" or "optional" are used to indicate the use or omission of certain substances, components, procedures, application conditions, etc.

[0088] In this instruction manual, when "room temperature" or "room temperature" is used, the temperature can be 15-25℃.

[0089] Unless otherwise specified, all reagents or instruments used in this instruction manual are commercially available products.

[0090] Examples 1-8

[0091] Examples 1-8 disclose a variety of two-step fabrication additives, which include a first fabrication agent and a second fabrication agent. The components and weight ratios of the first and second fabrication agents are shown in Table 1.

[0092] The first surfactant used in the first texturing agent is a gemini-type anionic polyether-modified silicone surfactant, the structure of which is shown in Formula I:

[0093]

[0094] In Formula I, m is the addition number of the -(CH3)2SiO group, and its value is an integer from 0 to 10;

[0095] n is the number of addition groups of EO, which is an integer between 5 and 100;

[0096] R is a sulfonic acid group or a carboxyl group.

[0097] The preparation method of the two-step flocking additive includes the following steps:

[0098] Preparation of the first texturing agent: At room temperature, all components except the first deionized water are added to 1 / 2 of the first deionized water and stirred until all components are completely mixed. Then, the remaining 1 / 2 of the first deionized water is added and stirring is continued for 2 hours to obtain the first texturing agent.

[0099] Preparation of the second texturing agent: At room temperature, add all components except the second deionized water to 1 / 2 of the second deionized water, stir until all components are completely mixed, then add the remaining 1 / 2 of the second deionized water, and continue stirring for 1 hour to obtain the second texturing agent.

[0100] Table 1. Components and weight ratios of the two-step fabrication additives in Examples 1-8

[0101]

[0102]

[0103] Comparative Examples 1-5

[0104] Comparative Examples 1-5 disclose various two-step texturing additives, each comprising a first texturing agent and a second texturing agent; the components and weight ratios of the first and second texturing agents are shown in Table 2. Their preparation methods are the same as in Example 1.

[0105] In Comparative Examples 1-3, the first surfactant used in the first texturing agent was a gemini-type anionic polyether-modified silicone surfactant, the same as in Example 1.

[0106] In Comparative Example 4, the first surfactant used in the first texturing agent has the structure shown in Formula II:

[0107]

[0108] Table 2 shows the components and weight ratios of the two-step flocking additives used in Comparative Examples 1-5.

[0109]

[0110]

[0111] Examples 9-16

[0112] Examples 9-16 disclose various two-step texturing solutions, the components and weight ratios of which are shown in Table 3.

[0113] The preparation method of the two-step texturing solution is as follows:

[0114] Preparation of the first texturing solution: The first texturing agent and alkali are added to deionized water at 83°C and stirred and mixed evenly to prepare the first texturing solution;

[0115] Preparation of the second texturing solution: The second texturing agent and alkali are added to deionized water at 68°C and stirred until homogeneous to prepare the second texturing solution.

[0116] Table 3. Components and weight ratios of the two-step texturing solutions in Examples 9-16

[0117]

[0118]

[0119] Comparative Examples 6-10

[0120] Comparative Examples 6-10 disclose various two-step texturing solutions, the components and weight ratios of which are shown in Table 4.

[0121] Table 4 shows the components and weight ratios of the two-step texturing solutions used in Comparative Examples 6-10.

[0122]

[0123]

[0124] The two-step texturing solutions of Examples 9-16 and Comparative Examples 6-10 were tested respectively. The test methods and results are as follows:

[0125] Fleece making method:

[0126] S1: The monocrystalline silicon wafer is placed in the first texturing solution for the first step of texturing. The texturing temperature is 82℃ and the texturing time is 300s.

[0127] S2: After texturing in step S1, the monocrystalline silicon wafer is rinsed in 40°C deionized water for 100 seconds, and then placed in the second texturing solution at 68°C for the second texturing step for 140 seconds.

[0128] S3: After texturing in step S2, rinse the front and back sides of the monocrystalline silicon wafer with deionized water and ethanol for 15 seconds each, and then dry them in an N2 atmosphere.

[0129] Table 3. Performance test data of the two-step texturing solution in Examples 9-16 and Comparative Examples 6-10

[0130] Example 9 27.0 0.99 8.5 Example 10 26.8 0.97 8.6 Example 11 26.2 0.93 8.5 Example 12 26.5 0.98 8.7 Example 13 25.6 0.95 8.5 Example 14 25.7 0.96 8.6 Example 15 25.3 0.97 8.8 Example 16 25.1 0.94 9.0 Comparative Example 6 24.8 0.61 13.0 Comparative Example 7 23.9 0.75 11.2 Comparative Example 8 21.5 0.73 12.3 Comparative Example 9 23.4 0.63 15.1 Comparative Example 10 22.8 0.79 10.3

[0131] Using Example 9 and Comparative Example 6 for texturing, 3D microscopy showed that the resulting textured silicon wafers had a similar pyramid size, around 1.0 μm. However, the pyramid height of Example 9 was slightly higher than that of Comparative Example 6, with the texture height of Example 9 around 0.99 μm and that of Comparative Example 6 around 0.61 μm. The most significant improvement was in reflection; Example 9 showed a reduction of approximately 4.5% in reflection compared to Comparative Example 6, with the reflection of Example 9 around 8.5% and that of Comparative Example 6 around 13%. The significant improvement in reflection in Example 9 is due to both the increased aspect ratio and, most importantly, the presence of the pyramid-shaped surface microstructure formed by the two-step texturing process, which further increases the effective optical path length of the submicron textured surface. The texture height of Comparative Examples 7-10 was lower than that of the Examples; their reflection was higher.

[0132] Performance testing:

[0133] Reflectivity measurement: velvet reflectometer.

[0134] Measurement of velour size, height, and density: 3D microscope.

[0135] Figure 1 and Figure 2 compared to, Figure 1 The pyramids on the textured silicon wafers are basically the same size, which proves that the two-step texturing process proposed in this invention has successfully achieved the preparation of microstructures on the pyramid surface, helping to achieve lower reflection in the submicron textured surface morphology.

[0136] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A two-step flocking additive, characterized in that, Including the first and second texturing agents; The first texturing agent comprises the following components by weight: 0.1-2 parts of down-forming agent; The first surfactant is 0.01-0.5 parts; 0.5-5 parts of the first etching catalyst; 1-5 parts of the first inorganic base; 50-90 parts of first-stage deionized water; The first etching catalyst is a phosphonic acid derivative; The first surfactant is a gemini-type anionic polyether-modified silicone surfactant, and its structure is shown in Formula I: ； Formula I; In Formula I, m is the addition number of the -(CH3)2SiO group, and its value is any integer from 0 to 10; n is the number of addition groups of EO groups, which can be any integer from 5 to 100; R is a sulfonic acid group or a carboxyl group; The second texturing agent comprises the following components by weight: The second surfactant is 0.01-2 parts; 1-5 parts of the second etching catalyst; 1-5 parts of the second inorganic base; 40-80 parts of second deionized water; The second surfactant is a nonionic surfactant or an amphoteric surfactant; The second etching catalyst is one or more of phosphonic acid and its derivatives.

2. The two-step flocking additive according to claim 1, characterized in that, The texturing agent is a natural low-viscosity polysaccharide polymer.

3. The two-step flocking additive according to claim 1 or 2, characterized in that, The down-producing agent is one or more of the following: guar gum, okra gum, flaxseed gum, acacia gum, and peach gum; And / or, the first etching catalyst is one or more of dimethylphosphonic acid, nonylphosphonic acid, diethylphosphonic acid, 2-hydroxyethylphosphonic acid, ibandronic acid, neridonic acid, risedronic acid, and zoledronic acid.

4. The two-step flocking additive according to claim 1, characterized in that, The second surfactant is one or more of the following: fatty alcohol polyoxyethylene ether AEO-9, cocoyl glucoside, fatty acid diethanolamide, octylphenol polyoxyethylene ether, nonylphenol polyoxyethylene ether, cocamidopropyl betaine, and cocamidopropyl hydroxysulfonate betaine.

5. A method for preparing the two-step flocking additive according to any one of claims 1-4, characterized in that, Includes the following steps: Preparation of the first texturing agent: At room temperature, add all components except the first deionized water to 1 / 3-1 / 2 of the first deionized water, stir until all components are completely mixed, then add the remaining first deionized water, and continue stirring to obtain the first texturing agent; Preparation of the second texturing agent: At room temperature, add all components except the second deionized water to 1 / 3 to 1 / 2 of the second deionized water, stir until all components are completely mixed, then add the remaining second deionized water and continue stirring to obtain the second texturing agent.

6. The application of the two-step texturing additive according to any one of claims 1-4 in the field of wet etching texturing of single crystal silicon.

7. A two-step texturing solution, characterized in that, The mixture includes a first texturing solution and a second texturing solution. The first texturing solution includes an alkali, deionized water, and a first texturing agent from the two-step texturing additives described in any one of claims 1-4. The second texturing solution includes an alkali, deionized water, and a second texturing agent from the two-step texturing additives described in any one of claims 1-4.

8. The two-step texturing solution according to claim 7, characterized in that, The first texturing solution comprises a first texturing agent, alkali, and deionized water in a mass ratio of 0.1-1:4-6:80-100; The second texturing solution comprises a second texturing agent, alkali, and deionized water in a mass ratio of 0.1-1:2-3:80-100.

9. A method for preparing the two-step texturing solution according to claim 7 or 8, characterized in that, Includes the following steps: Preparation of the first texturing solution: The first texturing agent and alkali are added to deionized water at 80-85℃ and stirred and mixed evenly to prepare the first texturing solution; Preparation of the second texturing solution: The second texturing agent and alkali are added to deionized water at 65-70℃ and stirred until homogeneous to prepare the second texturing solution.

10. The application of the two-step texturing solution of claim 7 or 8 in the field of wet etching texturing of single crystal silicon.

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