Monocrystalline silicon texturing additive, preparation method thereof and texturing liquid containing monocrystalline silicon texturing additive

Abstract

The invention provides a monocrystalline silicon texturing additive, a preparation method thereof and texturing liquid containing the monocrystalline silicon texturing additive. The texturing additive is prepared from the following raw material components in percentage by mass relative to the total weight of the monocrystalline silicon texturing additive: 0.1 to 0.8 percent of an alkaline reagent, 1.0 to 5.0 percent of a nucleating agent, 0.8 to 3.0 percent of a nucleating aid, 0.012 to 0.3 percent of a surfactant, 0.002 to 2.0 percent of a chelating agent, 0.001 to 6.0 percent of a dispersion stabilizer and the balance of deionized water. The monocrystalline silicon texturing additive can form a pyramid-like structure which is uniform in size and has concave side surfaces, so that the reflectivity is remarkably reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of solar cells, and more specifically to a texturing additive for single-crystal silicon and a preparation method thereof, as well as a texturing solution for single-crystal silicon wafers. Background Art

[0002] In the manufacture of photovoltaic cells, reducing the reflectivity of silicon wafer surfaces is a key step in improving light absorption efficiency. The reflectivity of untreated single-crystal silicon surfaces in the visible light band (400–1100 nm) is as high as over 30%, resulting in a large amount of incident light loss. Although traditional anti-reflection technologies (such as anti-reflection coatings) can partially improve optical performance, their performance is highly dependent on the surface morphology of the substrate. Studies have shown that the reflection suppression effect of direct coating on smooth single-crystal silicon surfaces is significantly inferior to that of a velvet-structured substrate. The light trapping effect brought about by this velvet-structured substrate forms a synergistic effect with the refractive index gradient effect of the anti-reflection film, making the velvet process a necessary prerequisite for achieving low reflection (<3%) in single-crystal silicon solar cells.

[0003] The wet-texturing pyramid structure forms a dense array of micron-scale pyramids on the surface of the silicon wafer through chemical etching, significantly reducing the reflectivity by utilizing multiple reflections and light trapping effects. However, the existing wet-texturing technology still faces bottlenecks in further reducing the reflectivity, mainly due to the following limitations: 1) Uniformity of pyramid morphology: Traditional alkaline etching forms random pyramids, which makes the size distribution of the pyramid morphology too wide (0.5μm–5μm), resulting in differences in local light scattering efficiency; 2) The influence of surface defects: Microcracks or "pits" generated during the etching process increase carrier recombination, offsetting the anti-reflection benefits; 3) Angle dependence: The anti-reflection effect of the random pyramid structure for oblique incident light decays rapidly (when the incident angle of the light is greater than 30°, the reflectivity rebounds). The latest research trends focus on breaking through the above limitations through precise control of morphology. Summary of the Invention

[0004] In view of the above, the purpose of the present invention is to provide a single crystal silicon texturing additive. The single crystal silicon texturing additive forms a pyramid-like structure of uniform size on the surface of the single crystal silicon through a combination of a specific content of an alkaline agent, a nucleating agent, a nucleating promoter, a surfactant, a chelating agent, and a dispersion stabilizer. At the same time, it also forms an inwardly concave side surface on the side of the pyramid-like structure, which increases the chance of secondary reflection compared to a traditional pyramid structure and further reduces the reflectivity of the single crystal silicon surface. In addition, the single crystal silicon texturing additive is low in cost and suitable for mass production.

[0005] Furthermore, another object of the present invention is to provide a method for preparing a single crystal silicon texturing additive.

[0006] Furthermore, another object of the present invention is to provide a texturing solution for single crystal silicon wafers, wherein the texturing solution comprises the single crystal silicon texturing additive and an alkaline aqueous solution.

[0007] The above-mentioned object of the present invention is achieved through the following technical solutions.

[0008] On the one hand, the present invention provides a single crystal silicon texturing additive, the raw materials of which include the following components: relative to the total weight of the single crystal silicon texturing additive, 0.1 mass%~0.8 mass% of alkaline reagent, 1.0 mass%~5.0 mass% of nucleating agent, 0.8 mass%~3.0 mass% of nucleating agent, 0.012 mass%~0.3 mass% of surfactant, 0.002 mass%~2.0 mass% of chelating agent, 0.001 mass%~6.0 mass% of dispersion stabilizer and the balance deionized water.

[0009] Optionally, the alkaline reagent is one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium acetate, potassium acetate and ammonia water.

[0010] Optionally, the nucleating agent is one or more of water-soluble polyethers and water-soluble alcohols.

[0011] Optionally, the nucleating agent is one or more of organic acid salts and alcohols.

[0012] Optionally, the surfactant is one or more anionic surfactants.

[0013] Optionally, the chelating agent is one or more polydentate chelating agents.

[0014] Optionally, the dispersion stabilizer is one or more water-soluble electrolytes.

[0015] Optionally, the nucleating agent is one or more of alkoxy-containing water-soluble polyethers and polyhydroxy-containing water-soluble alcohols; the nucleating agent is one or more of potassium tartrate, sodium benzoate, ethylene glycol and 1,3-propylene glycol; the surfactant is one or both of sodium hexadecyl diphenyl ether sulfonate and sodium polyoxyethylene alkyl alcohol ether sulfate; the chelating agent is one or both of sodium ethylenediaminetetramethylenephosphonate and disodium EDTA; and / or the dispersion stabilizer is one or more of sodium tripolyphosphate, sodium hexametaphosphate and sodium pyrophosphate.

[0016] On the other hand, the present invention provides a method for preparing a single crystal silicon texturing additive, which is a method for preparing the single crystal silicon texturing additive, comprising the following steps: (1) Adding an alkaline reagent into deionized water, stirring and dissolving, to obtain an alkaline aqueous solution system; (2) At room temperature, the nucleating agent, the nucleating agent, the surfactant, the chelating agent, the dispersing stabilizer and the balance deionized water are sequentially added to the alkaline aqueous solution system, and stirring is continued during the addition of each component to finally obtain a single crystal silicon texturing additive.

[0017] On the other hand, the present invention provides a texturing solution for single crystal silicon wafers, the texturing solution comprising the single crystal silicon texturing additive and an alkaline aqueous solution, wherein the mass ratio of the texturing additive to the alkaline aqueous solution is 0.2-0.5:100.

[0018] The present invention can produce the following beneficial technical effects: The present invention, for the first time, uses a combination of specific amounts of alkaline reagents, nucleating agents, nucleating promoters, surfactants, chelating agents, and dispersing stabilizers in a single-crystal silicon texturing additive to form a pyramid structure of uniform size on the surface of the single-crystal silicon while also forming an inward-concave structure on the side of the pyramid structure. Since the pyramid-like structure of uniform size with inward-concave sides has more multiple reflections than the traditional pyramid structure, the reflectivity of the single-crystal silicon wafers produced using the single-crystal silicon texturing additive of the present invention is significantly reduced. While having an excellent texturing effect, the preparation method of the single-crystal silicon texturing additive of the present invention is simple, low-cost, and has safe and environmentally friendly ingredients, making it suitable for mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the implementation cases of this application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. All other implementation methods obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0020] Figure 1 This is a scanning electron microscope test image of the pyramid morphology obtained after texturing in Example 1 (taken at a 0° angle); Figure 2 : This is a scanning electron microscope test image of the pyramid morphology obtained after texturing in Example 1 (taken at a 45° angle); Figure 3 This is a scanning electron microscope test image of the pyramid morphology obtained after texturing in Example 1 (taken at a 90° angle). DETAILED DESCRIPTION

[0021] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the following specific embodiments. Obviously, the specific embodiments described are part of the embodiments of the present invention. Based on the described embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] According to one aspect of the present invention, a single crystal silicon texturing additive is provided, wherein the raw materials of the texturing additive include the following components: relative to the total weight of the single crystal silicon texturing additive, 0.1-0.8 mass% of an alkaline agent, preferably 0.4-0.6 mass% and more preferably 0.5 mass%; 1.0-5.0 mass% of a nucleating agent, preferably 1.5-3.5 mass% and more preferably 1.8-2.6 mass%; 0.8-3.0 mass% of a nucleating agent, preferably 1.2-2.8 mass% and more preferably The composition comprises the following components: a surfactant (0.012-0.3 mass%, preferably 0.019-0.280 mass%, more preferably 0.15-0.20 mass%); a chelating agent (0.002-2.0 mass%, preferably 0.05-1.6 mass%, more preferably 0.08-1.2 mass%); a dispersion stabilizer (0.001-6.0 mass%, preferably 0.8-3.9 mass%, more preferably 1.6-2.2 mass%); and the balance deionized water.

[0023] In the single crystal silicon texturing additive of the present invention, a certain concentration of nucleating agent can be uniformly adsorbed on the surface of the single crystal silicon to form uniformly dispersed adsorption points, and these adsorption points can form masking points on the surface of the single crystal silicon, and the remaining unadsorbed areas will be etched under the action of the alkaline solution, which lays the foundation for the formation of the pyramid. The nucleating agent in the single crystal silicon texturing additive of the present invention selectively adsorbs on high-energy crystal planes such as Si (110), suppressing their etching rate, while the Si (100) crystal plane continues to etch rapidly in an alkaline environment. This difference causes the sides of the formed pyramid structure to be concave inward. The surfactant in the single crystal silicon texturing additive of the present invention can reduce the interfacial energy of the silicon liquid, causing a "retraction effect" at the side wall of the pyramid structure at the etching front, further promoting the formation of the concave morphology of the side surface.

[0024] In addition, the nucleating agent and the dispersing stabilizer in the single crystal silicon texturing additive of the present invention can form a soluble complex, accelerate the etching in the vertical direction, and locally block the progress of lateral etching, thereby causing the Si (100) surface to preferentially sink inward during the etching process, while the Si (111) surface, as a slow-etching surface, forms the edge of the pyramid, thereby promoting the formation of an inward-concave morphology on the side.

[0025] The surfactant in the monocrystalline silicon texturing additive of the present invention can effectively adjust the surface tension of the texturing solution, thereby controlling the desorption rate of bubbles generated during the texturing process within a suitable range, thereby ensuring the uniformity and aesthetics of the pyramid velvet surface.

[0026] According to a preferred embodiment of the present invention, the alkaline agent can be one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium acetate, potassium acetate and ammonia water, preferably sodium hydroxide.

[0027] According to a preferred embodiment of the present invention, the nucleating agent is one or more water-soluble polyethers and water-soluble alcohols. The water-soluble polyethers may be one or more water-soluble polyethers containing alkoxy groups, preferably polyethylene glycol (molecular weight 200-600) and / or propylene glycol block polyether; the water-soluble alcohols may be one or more water-soluble alcohols containing polyhydroxy groups, preferably polyvinyl alcohol 1799, polyvinyl alcohol 2488, liquid polyvinyl alcohol 0388 and / or liquid polyvinyl alcohol 0599.

[0028] According to a preferred embodiment of the present invention, the nucleating agent is one or more of organic acid salts and alcohols, and the organic acid salts can be one or more of cinnamic acid, potassium sorbate, potassium tartrate and sodium benzoate, preferably potassium tartrate and sodium benzoate; the alcohol can be one or more of ethylene glycol, 1,4-cyclohexanediol, isohexanediol, 1,4-butanediol and 1,3-propylene glycol, preferably ethylene glycol and 1,3-propylene glycol.

[0029] According to a preferred embodiment of the present invention, the surfactant is one or more anionic surfactants, and the anionic surfactant can be one or more of sodium cetyl diphenyl ether sulfonate, sodium dodecyl sulfate, sodium dodecylbenzene sulfonate and sodium alkyl ether polyoxyethylene ether sulfate, preferably sodium cetyl diphenyl ether sulfonate and / or sodium alkyl alcohol polyoxyethylene ether sulfate.

[0030] According to a preferred embodiment of the present invention, the chelating agent is one or more polydentate chelating agents, which may be one or more of sodium ethylenediaminetetramethylenephosphonate, disodium EDTA, tetrasodium EDTA, and trisodium NTA, preferably sodium ethylenediaminetetramethylenephosphonate or disodium EDTA. The polydentate chelating agent has a polydentate chelating ability.

[0031] According to a preferred embodiment of the present invention, the dispersion stabilizer is one or more water-soluble electrolytes, and the dispersion stabilizer can be one or more of sodium carbonate, sodium polyacrylate, partially hydrolyzed polyacrylamide, sodium tripolyphosphate, sodium hexametaphosphate and sodium pyrophosphate, preferably sodium tripolyphosphate, sodium hexametaphosphate or sodium pyrophosphate.

[0032] According to a preferred embodiment of the present invention, the single crystal silicon texturing additive is used to prepare a single crystal silicon wafer having a pyramid-like morphology with concave side surfaces.

[0033] On the other hand, the present invention provides a method for preparing a single crystal silicon texturing additive, which is a method for preparing the single crystal silicon texturing additive, comprising the following steps: (1) Adding an alkaline reagent of electronic grade purity into deionized water, stirring and dissolving, to obtain an alkaline aqueous solution system; (2) Add the nucleating agent to the alkaline aqueous solution system at room temperature, stir and dissolve at room temperature; then add the nucleating agent, stir evenly at room temperature until it is clear; then add the surfactant, stir evenly at room temperature until it is clear; then add the chelating agent, stir evenly until it is clear; add the dispersion stabilizer, stir evenly until it is clear; finally, add the remaining amount of deionized water to prepare the single crystal silicon texturing additive.

[0034] On the other hand, the present invention provides a texturing liquid for single crystal silicon wafers, the texturing liquid comprising the single crystal silicon texturing additive and an alkaline aqueous solution, wherein the mass ratio of the texturing additive to the alkaline aqueous solution is 0.2-0.5:100, preferably 0.35:100.

[0035] If the mass ratio of the monocrystalline silicon texturing additive to the alkaline aqueous solution is too high or too low, the nucleating agent will not be evenly adsorbed on the surface of the monocrystalline silicon wafer, and thus will not form uniform masking points on the surface of the monocrystalline silicon wafer. Specifically, when the mass ratio of the monocrystalline silicon texturing additive to the alkaline aqueous solution is too high, the nucleating agent content is excessive, resulting in an overly dense nucleating agent adsorption point density and excessive masking, which will cause the pyramid-like arrangement of the produced velvet surface to be too dense. Furthermore, due to the certain aspect ratio of the pyramid-like structure, the resulting pyramid-like structure will be too small and short, which is not conducive to reducing reflectivity and may even cause the velvet surface to be reflective. When the mass ratio of the monocrystalline silicon texturing additive to the alkaline aqueous solution is too low, the nucleating agent content is insufficient, resulting in fewer nucleating agent adsorption points and insufficient masking points on the monocrystalline silicon wafer surface. This will cause corrosion over a large area of ​​the monocrystalline silicon wafer and prevent the formation of sufficient pyramid-like morphology, resulting in a partially missing velvet surface, uneven texture, and excessively high reflectivity.

[0036] Example The embodiments of the present invention use the following test methods to test aspect ratio, curvature radius and reflectivity performance.

[0037] 1. Test Method (1) Aspect ratio test According to the international standard SEMI PV22-0212 (Guidelines for Silicon Wafer Surface Texturing), which recommends using SEM or optical methods to characterize textured structures, the aspect ratio measurement method of this invention is performed. Using a scanning electron microscope (SEM) to directly measure the cross-sectional images of pyramids on the surface of a single-crystal silicon wafer, the height (h) and base width (w) of each pyramid are directly measured, and the aspect ratio (AR) is calculated as h / w. The test results for each sample are expressed as the average range of three measurements.

[0038] (2) Test of curvature radius By using a scanning electron microscope (COXEM Co., Ltd., South Korea) to photograph the pyramid structure on the surface of a single-crystal silicon wafer, the central axis of the pyramid structure is used as the y-axis, and the base of the pyramid is used as the x-axis. The coordinates of the top, middle, and bottom points of the curved arc are selected. The arc function f(x)=y=ax can be fitted based on the coordinates of these three points. 2 +bx+c, calculate the values ​​of a, b and c.

[0039] Then, according to the curvature k=|y| / (1+(y) 2 ) 3 / 2 , the radius of curvature R = 1 / k, and the derivative of y, y' = dy / dx, and y' again derivative, get a fixed value y''. According to k = y'' / (1+(y') 2 ) 3 / 2 , by substituting any one of the three points, the curvature radius R can be calculated.

[0040] In the image captured by SEM (90-degree cross-section), three groups of two pyramids of different sizes were selected. The radius of curvature of the pyramid sides was calculated for each group, and the average value was calculated. This average value represents the test result for each sample.

[0041] (3) Reflectivity test The reflectivity of the single crystal silicon wafer of the present invention is tested according to the standard GB / T 31351-2014 "Test method for texture surface of crystalline silicon solar cells".

[0042] 2. Preparation Process of Texturing Additive and Single Crystal Silicon Wafer for Examples (1) Preparation process of texturing additives Deionized water was added to a dosing and stirring tank, and an alkaline reagent was added to the deionized water. After stirring and dissolving, an alkaline aqueous solution system was obtained. At room temperature, a nucleating agent, a nucleating promoter, a surfactant, a chelating agent, and a dispersion stabilizer as shown in Table 1 were added to the alkaline aqueous solution system in sequence with continuous stirring. After the first component was stirred evenly until clear, the next component was added. Finally, the remaining amount of deionized water was added and stirred evenly to obtain a single crystal silicon texturing additive.

[0043] (2) Preparation process of texturing agent A sodium hydroxide alkaline aqueous solution with a mass fraction of 0.5% is prepared. According to the mass ratio of the single crystal silicon texturing additive of the present invention to the alkaline aqueous solution is 0.2-0.5:100. The single crystal silicon texturing additive of the present invention is added to the sodium hydroxide alkaline aqueous solution, and after stirring evenly, a texturing liquid is prepared.

[0044] (3) Preparation process of single crystal silicon wafers The single crystal silicon wafer is immersed in a 60-65°C cleaning solution in a cleaning tank for cleaning pretreatment, and the cleaning pretreatment time is 2-5 minutes; the single crystal silicon wafer after cleaning pretreatment is immersed in an alkaline solution in an alkaline polishing tank for alkaline polishing, and the reaction temperature of the alkaline polishing is 70-72°C, and the time is 1-3 minutes; the polished single crystal silicon wafer is sent to a spray device, and the polished single crystal silicon wafer is corroded by spraying the texturing liquid of the present invention, and the temperature of the texturing liquid is 72-75°C, and the reaction time is 300-410s; then the texturized single crystal silicon wafer is spray cleaned; the cleaned texturized single crystal silicon wafer is sent to a drying chamber for drying; after drying, a single crystal silicon wafer is obtained.

[0045] 3. Examples 1-9 and Comparative Examples 1-4 Unless otherwise specified, the raw materials and equipment used in the present invention are commonly used in this field.

[0046] Example 1 20% by mass of deionized water, relative to the total weight of the single crystal silicon texturing additive, was added to a dosing and stirring bucket. 0.1% by mass of sodium hydroxide was added to the deionized water, stirred and dissolved, to obtain an alkaline aqueous solution system. At room temperature, 1.9% by mass of polyethylene glycol (molecular weight 600), 1.6% by mass of potassium tartrate, 0.17% by mass of sodium hexadecyl diphenyl ether sulfonate, 1.0% by mass of sodium ethylenediamine tetramethylenephosphonate, and 1.7% by mass of sodium tripolyphosphate were sequentially added to the alkaline aqueous solution system with continuous stirring. After the first component was stirred uniformly until clear, the second component was added. Finally, the remaining amount of deionized water was added and stirred uniformly to obtain the single crystal silicon texturing additive.

[0047] A sodium hydroxide alkaline aqueous solution with a mass fraction of 0.5% is prepared, and the single crystal silicon texturing additive of the present invention is added to the sodium hydroxide alkaline aqueous solution according to a mass ratio of the single crystal silicon texturing additive to the alkaline aqueous solution of 0.5:100. After stirring evenly, a texturing liquid is prepared.

[0048] The single crystal silicon wafer is immersed in a 60-65°C cleaning solution in a cleaning tank for cleaning pretreatment, and the cleaning pretreatment time is 2-5 minutes; the single crystal silicon wafer after cleaning pretreatment is immersed in an alkaline solution in an alkaline polishing tank for alkaline polishing, and the reaction temperature of the alkaline polishing is 70-72°C, and the time is 1-3 minutes; the polished single crystal silicon wafer is sent to a spray device, and the polished single crystal silicon wafer is corroded by spraying the texturing liquid of the present invention, and the temperature of the texturing liquid is 72-75°C, and the reaction time is 300-410s; then the texturized single crystal silicon wafer is spray cleaned; the cleaned texturized single crystal silicon wafer is sent to a drying chamber for drying; after drying, a single crystal silicon wafer is obtained.

[0049] Example 2 20% by mass of deionized water, relative to the total weight of the single-crystal silicon texturing additive, was added to a dosing and stirring tank. 0.1% by mass of sodium hydroxide was added to the deionized water and stirred until dissolved to obtain an alkaline aqueous solution. At room temperature, 1.1% by mass of polyethylene glycol (molecular weight 600), 0.9% by mass of potassium tartrate, 0.015% by mass of sodium hexadecyl diphenyl ether sulfonate, 0.005% by mass of sodium ethylenediaminetetramethylenephosphonate, and 0.007% by mass of sodium tripolyphosphate were added to the alkaline aqueous solution in this order. The remaining steps were the same as in Example 1.

[0050] Example 3 20% by mass of deionized water, relative to the total weight of the single-crystal silicon texturing additive, was added to a dosing and stirring tank. 0.1% by mass of sodium hydroxide was added to the deionized water and stirred until dissolved to obtain an alkaline aqueous solution. At room temperature, 4.8% by mass of polyethylene glycol (molecular weight 600), 2.8% by mass of potassium tartrate, 0.27% by mass of sodium hexadecyl diphenyl ether sulfonate, 1.6% by mass of sodium ethylenediaminetetramethylenephosphonate, and 5.1% by mass of sodium tripolyphosphate were added to the alkaline aqueous solution in this order. The remaining steps were the same as in Example 1.

[0051] Example 4 1.9 mass % of polyethylene glycol (molecular weight 600) was replaced by 1.9 mass % of polyvinyl alcohol 1799. The remaining steps were the same as those in Example 1.

[0052] Example 5 1.9 mass % of polyethylene glycol (molecular weight 600) was replaced by 1.9 mass % of propylene glycol block polyether. The remaining steps were the same as in Example 1.

[0053] Example 6 1.9 mass % of polyethylene glycol (molecular weight 600) was replaced with 1.9 mass % of liquid polyvinyl alcohol 0388. The remaining steps were the same as those in Example 1.

[0054] Example 7 20% by mass of deionized water, relative to the total weight of the single-crystal silicon texturing additive, was added to a dosing and stirring tank. 0.1% by mass of sodium hydroxide was added to the deionized water, stirred, and dissolved to obtain an alkaline aqueous solution. At room temperature, 1.9% by mass of polyethylene glycol (molecular weight 600), 1.0% by mass of polyvinyl alcohol 1799, 1.6% by mass of ethylene glycol, 0.17% by mass of sodium hexadecyl diphenyl ether sulfonate, 1.0% by mass of sodium ethylenediaminetetramethylenephosphonate, and 1.7% by mass of sodium tripolyphosphate were sequentially added to the alkaline aqueous solution. The remaining steps were the same as in Example 1.

[0055] Example 8 Relative to the total weight of the single crystal silicon texturing additive, 20% by mass of deionized water was added to a dosing stirring barrel, 0.1% by mass of sodium hydroxide was added to the deionized water, stirred and dissolved, to obtain an alkaline aqueous solution system. At room temperature, 1.9% by mass of propylene glycol block polyether, 1.0% by mass of liquid polyvinyl alcohol 0388, 1.6% by mass of ethylene glycol, 0.17% by mass of sodium hexadecyl diphenyl oxide sulfonate, 1.0% by mass of sodium ethylenediamine tetramethylenephosphonate, and 1.7% by mass of sodium tripolyphosphate were added to the alkaline aqueous solution system in sequence. The remaining steps were the same as in Example 1.

[0056] Example 9 Relative to the total weight of the monocrystalline silicon texturing additive, 20% by mass of deionized water was added to the dosing stirring barrel, 0.1% by mass of sodium hydroxide was added to the deionized water, stirred and dissolved, and an alkaline aqueous solution system was obtained. At room temperature, 1.0% by mass of polyvinyl alcohol 1799, 1.9% by mass of propylene glycol block polyether, 0.5% by mass of ethylene glycol, 1.6% by mass of 1,3-propylene glycol, 0.17% by mass of sodium alkyl alcohol polyoxyethylene ether sulfate, 1.0% by mass of sodium ethylenediamine tetramethylenephosphonate, 0.5% by mass of sodium tripolyphosphate, 1.0% by mass of sodium hexametaphosphate and 0.8% by mass of sodium pyrophosphate were added to the alkaline aqueous solution system in sequence. The remaining steps were the same as in Example 1.

[0057] Comparative Example 1 The remaining steps were the same as those in Example 1 except that 1.9% by mass of polyethylene glycol (molecular weight 600) was replaced with 0.5% by mass of polyethylene glycol (molecular weight 600).

[0058] Comparative Example 2 The remaining steps were the same as in Example 1 except that 1.9% by mass of polyethylene glycol (molecular weight 600) was replaced by 5.8% by mass of polyethylene glycol (molecular weight 600), and 1.6% by mass of potassium tartrate was replaced by 0.9% by mass of potassium tartrate.

[0059] Comparative Example 3 The remaining steps were the same as those in Example 1 except that 1.6% by mass of potassium tartrate was replaced with 0.6% by mass of potassium tartrate.

[0060] Comparative Example 4 The remaining steps were the same as in Example 1 except that 1.9% by mass of polyethylene glycol (molecular weight 600) was replaced by 4.8% by mass of polyethylene glycol (molecular weight 600), and 1.6% by mass of potassium tartrate was replaced by 3.5% by mass of potassium tartrate.

[0061] Table 1. Content of each component in the texturing additive of the present invention

[0062] Table 2. Content of each component in the comparative example

[0063] 4. Effect of Components of Single Crystal Silicon Texturing Additive on Pyramidal Structure and Properties of Textured Surface Table 3. Effects of various components in single crystal silicon texturing additives on the texture structure and properties

[0064] It can be seen from the test results of the embodiments and comparative examples in Tables 1 to 3 that: According to Examples 1 to 6 and Comparative Examples 1 to 4, the use of the texturing additive of the present invention can obtain a pyramid-like structure with uniform size and concave side surfaces with a curvature radius of 7.00 to 7.50 μm, thereby further reducing the reflectivity of the single crystal silicon wafer to 8.1%-8.9%.

[0065] If the nucleating agent content is below the content range of the present invention (Comparative Example 1), the pyramids on the surface of the resulting single-crystal silicon wafer are oversized and have a large radius of curvature, ultimately resulting in excessively high reflectivity. If the nucleating agent content is above the content range of the present invention (Comparative Example 2), the pyramids on the surface of the resulting single-crystal silicon wafer are too small and too densely arranged, preventing the pyramids from growing and resulting in a low aspect ratio, ultimately resulting in excessively high reflectivity. Furthermore, if the nucleating agent content is above or below the content range of the nucleating agent of the present invention (Comparative Examples 3 and 4), the size of the pyramids on the surface of the single-crystal silicon wafer and the radius of curvature of the concave side surfaces of the pyramids will also be affected, resulting in excessively high reflectivity of the single-crystal silicon wafer, failing to meet the requirements of the present invention. Thus, the effect of the single-crystal silicon texturing additive of the present invention on the pyramid morphology does not rely on a single component, but rather is achieved through the combined action of the specific contents of the components in the single-crystal silicon texturing additive, ultimately reducing the reflectivity of the single-crystal silicon wafer.

[0066] Furthermore, Examples 7-9 of the present invention demonstrate that the combined use of multiple nucleating agents or multiple nucleating promoters can further reduce the reflectivity of single-crystal silicon wafers while reducing the amount of nucleating agent or nucleating promoter added. This indicates that the combined use of multiple nucleating agents and / or multiple nucleating promoters can further reduce the radius of curvature of the pyramid-like concave side surfaces of the single-crystal silicon wafer, thereby further reducing the reflectivity of the single-crystal silicon wafer.

[0067] In summary, the monocrystalline silicon texturing additive of the present invention can form a pyramid structure with uniform size and concave side faces on the surface of the monocrystalline silicon, thereby significantly reducing the reflectivity of the monocrystalline silicon wafer.

[0068] The technical solution of the present invention is not limited to the specific embodiments or examples described above. The specific embodiments or examples described above are merely illustrative and not restrictive. Those skilled in the art may make many improvements and variations based on the specific embodiments or examples described herein without departing from the spirit of the present invention and the scope of protection of the claims. Such improvements and variations shall fall within the scope of protection of the present invention.

Claims

1. A single crystal silicon texturing additive, characterized in that: The raw materials of the texturing additive include the following components: Relative to the total weight of the single crystal silicon texturing additive, the alkaline agent is 0.1 mass% to 0.8 mass%, the nucleating agent is 1.0 mass% to 5.0 mass%, the nucleating agent is 0.8 mass% to 3.0 mass%, the surfactant is 0.012 mass% to 0.3 mass%, the chelating agent is 0.002 mass% to 2.0 mass%, the dispersion stabilizer is 0.001 mass% to 6.0 mass% and the balance is deionized water.

2. The single crystal silicon texturing additive according to claim 1, characterized in that: The alkaline reagent is one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium acetate, potassium acetate and ammonia water.

3. The single crystal silicon texturing additive according to claim 1, characterized in that: The nucleating agent is one or more of water-soluble polyethers and water-soluble alcohols.

4. The single crystal silicon texturing additive according to any one of claims 1 to 3, characterized in that: The nucleating agent is one or more of organic acid salts and alcohols.

5. The single crystal silicon texturing additive according to any one of claims 1 to 3, characterized in that: The surfactant is one or more anionic surfactants.

6. The single crystal silicon texturing additive according to any one of claims 1 to 3, characterized in that: The chelating agent is one or more polydentate chelating agents.

7. The single crystal silicon texturing additive according to any one of claims 1 to 3, characterized in that: The dispersion stabilizer is one or more water-soluble electrolytes.

8. The single crystal silicon texturing additive according to any one of claims 1 to 3, characterized in that: The nucleating agent is one or more of alkoxy-containing water-soluble polyethers and polyhydroxy-containing water-soluble alcohols; the nucleating agent is one or more of potassium tartrate, sodium benzoate, ethylene glycol and 1,3-propylene glycol; the surfactant is one or both of sodium hexadecyl diphenyl ether sulfonate and sodium polyoxyethylene alkyl alcohol ether sulfate; the chelating agent is one or both of sodium ethylenediaminetetramethylenephosphonate and disodium EDTA; and / or the dispersion stabilizer is one or more of sodium tripolyphosphate, sodium hexametaphosphate and sodium pyrophosphate.

9. A method for preparing a single crystal silicon texturing additive, characterized in that: The method for preparing the single crystal silicon texturing additive according to any one of claims 1 to 8 comprises the following steps: (1) Adding an alkaline reagent into deionized water, stirring and dissolving, to obtain an alkaline aqueous solution system; (2) At room temperature, the nucleating agent, the nucleating agent, the surfactant, the chelating agent, the dispersing stabilizer and the balance deionized water are sequentially added to the alkaline aqueous solution system, and stirring is continued during the addition of each component to finally obtain a single crystal silicon texturing additive.

10. A texturing solution for single crystal silicon wafers, characterized in that: The texturing solution comprises the single crystal silicon texturing additive according to any one of claims 1 to 8 and an alkaline aqueous solution, wherein the mass ratio of the texturing additive to the alkaline aqueous solution is 0.2-0.5:100.

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