A single crystal silicon texturing additive, a preparation method thereof and a texturing solution comprising the same

Abstract

The present application provides a single crystal silicon texturing additive, a preparation method thereof and a texturing solution comprising the same. The raw material of the texturing additive comprises the following components: 0.1-0.8 mass% of an alkaline reagent, 1.0-5.0 mass% of a nucleating agent, 0.8-3.0 mass% of a nucleating aid, 0.012-0.3 mass% of a surfactant, 0.002-2.0 mass% of a chelating agent, 0.001-6.0 mass% of a dispersion stabilizer and the balance of deionized water, relative to the total weight of the single crystal silicon texturing additive. The single crystal silicon texturing additive can form a pyramid-like structure with uniform size and concave side surface, so as to significantly reduce the reflectivity.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of solar cells. More particularly, it relates to a single crystal silicon texturing additive and a preparation method thereof, and a single crystal silicon wafer texturing solution. BACKGROUND

[0002] In the manufacture of photovoltaic cells, reducing the reflectivity of the silicon wafer surface is a key link to improve light absorption efficiency. The reflectivity of the untreated single crystal silicon surface in the visible light band (400-1100 nm) is as high as more than 30%, resulting in a large amount of incident light loss. Although the traditional anti-reflection technology (such as anti-reflection coating) can partially improve the optical performance, its performance is highly dependent on the surface morphology of the substrate. Studies have shown that the reflection suppression effect of directly coating the film on the smooth single crystal silicon surface is significantly worse than that of the textured structure substrate. The light trapping effect brought by this textured structure substrate and the refractive index gradient effect of the anti-reflection film form a synergistic effect, so that the texturing process becomes a necessary prerequisite for single crystal silicon solar cells to achieve low reflectivity (<3%).

[0003] The wet texturing pyramid structure forms a dense array of micron-scale pyramids on the surface of the silicon wafer through chemical etching, and significantly reduces the reflectivity by using multiple reflection and light trapping effects. However, the existing wet texturing technology still faces the bottleneck of further reducing the reflectivity, which is mainly limited by: 1) uniformity of pyramid morphology: the traditional alkaline etching forms random pyramids, resulting in a wide size distribution of the pyramid morphology (0.5 μm-5 μm), which leads to differences in local light scattering efficiency; 2) influence of surface defects: micro-cracks or "pits" generated during the etching process will increase the carrier recombination, which offsets the anti-reflection benefits; 3) angle dependence: the random pyramid structure attenuates the anti-reflection effect of oblique incident light quickly (when the incident angle of light is > 30°, the reflectivity rises again). The latest research trend focuses on breaking through the above limitations through precise control of the morphology. SUMMARY

[0004] In view of the above, the purpose of the present application is to provide a single crystal silicon texturing additive, which, by combining specific contents of alkaline reagents, nucleating agents, nucleating aids, surfactants, chelating agents, and dispersion stabilizers, forms a pyramid-like structure with uniform size on the surface of the single crystal silicon, and also forms a concave side on the side of the pyramid-like structure, which increases the opportunity for secondary reflection compared to the traditional pyramid structure, further reducing 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] Further, another purpose of the present application is to provide a preparation method of a single crystal silicon texturing additive.

[0006] Further, another object of the present application is to provide a single crystal silicon wafer etching solution, which comprises the single crystal silicon etching additive and an alkaline aqueous solution.

[0007] The above-mentioned objects of the present application are achieved by the following technical solutions.

[0008] In one aspect, the present application provides a single crystal silicon etching additive, which comprises the following components: 0.1-0.8% by mass of an alkaline agent, 1.0-5.0% by mass of a nucleating agent, 0.8-3.0% by mass of a nucleating aid, 0.012-0.3% by mass of a surfactant, 0.002-2.0% by mass of a chelating agent, 0.001-6.0% by mass of a dispersion stabilizer, and the balance of deionized water, relative to the total weight of the single crystal silicon etching additive.

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

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

[0011] Optionally, the nucleating aid is one or more of organic acid salt and alcohol.

[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 water-soluble polyether containing alkoxyl group and water-soluble alcohol containing polyhydroxy group; the nucleating aid is one or more of potassium tartrate, sodium benzoate, ethylene glycol, and 1,3-propanediol; the surfactant is one or both of sodium hexadecyl diphenyl ether sulfonate and alkyl alcohol polyoxyethylene ether sodium sulfate; the chelating agent is one or both of sodium ethylenediamine tetramethylene phosphonate and disodium EDTA; and / or the dispersion stabilizer is one or more of sodium tripolyphosphate, sodium hexametaphosphate, and sodium pyrophosphate.

[0016] In another aspect, the present application provides a preparation method of a single crystal silicon etching additive, which is a method for preparing the single crystal silicon etching additive, comprising the following steps:

[0017] (1) adding an alkaline agent into deionized water, stirring and dissolving to obtain an alkaline aqueous solution system;

[0018] (2) At room temperature, the nucleating agent, nucleating agent, surfactant, chelating agent, dispersing stabilizer and the balance deionized water are added sequentially to the alkaline aqueous solution system, and the mixture is continuously stirred during the addition of each component to finally obtain a single crystal silicon texturing additive.

[0019] In another aspect, the present invention provides a texturing solution for monocrystalline silicon wafers, the texturing solution comprising the monocrystalline 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.

[0020] The present invention can produce the following beneficial technical effects:

[0021] This invention, for the first time, utilizes a combination of specific amounts of alkaline reagents, nucleating agents, nucleation aids, surfactants, chelating agents, and dispersing stabilizers in a monocrystalline silicon texturing additive to create a uniformly sized pyramidal structure on the surface of monocrystalline silicon, while simultaneously forming a concave structure on the sides of the pyramidal structure. Because the uniformly sized pyramidal structure with concave sides increases reflections compared to a traditional pyramidal structure, the reflectivity of monocrystalline silicon wafers fabricated using this invention's monocrystalline silicon texturing additive is significantly reduced. In addition to its excellent texturing effect, the preparation method of this invention's monocrystalline silicon texturing additive is simple, low-cost, and its components are safe and environmentally friendly, making it suitable for mass production. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the implementation examples of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. All other implementation methods obtained by those skilled in the art without creative effort are within the protection scope of this invention.

[0023] Figure 1 The image shows a scanning electron microscope (SEM) image of the pyramidal morphology obtained after texturing in Example 1 (taken at 0° angle).

[0024] Figure 2 This is a scanning electron microscope (SEM) image of the pyramidal morphology obtained after texturing in Example 1 (taken at a 45° angle).

[0025] Figure 3 The image shows a scanning electron microscope (SEM) image of the pyramidal morphology obtained after texturing in Example 1 (taken at a 90° angle). Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the following specific embodiments. Obviously, the described specific embodiments are only a part of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0027] According to one aspect of the present invention, a texturing additive for monocrystalline silicon is provided, wherein the raw materials of the texturing additive comprise the following components: relative to the total weight of the monocrystalline silicon texturing additive, an alkaline reagent of 0.1-0.8% by mass, preferably 0.4-0.6% by mass, more preferably 0.5% by mass; a nucleating agent of 1.0-5.0% by mass, preferably 1.5-3.5% by mass, more preferably 1.8-2.6% by mass; and a nucleation aid of 0.8-3.0% by mass, preferably 1.2-2.8% by mass, more preferably... The composition is 1.5 to 2.4% by mass; surfactant 0.012 to 0.3% by mass, preferably 0.019 to 0.280% by mass, more preferably 0.15 to 0.20% by mass; chelating agent 0.002% to 2.0% by mass, preferably 0.05 to 1.6% by mass, more preferably 0.08 to 1.2% by mass; dispersing stabilizer 0.001 to 6.0% by mass, preferably 0.8 to 3.9% by mass, more preferably 1.6 to 2.2% by mass; and the balance being deionized water.

[0028] In the monocrystalline silicon texturing additive of the present invention, a certain concentration of nucleating agent can be uniformly adsorbed on the surface of monocrystalline silicon, forming uniformly dispersed adsorption points. These adsorption points can form masking points on the surface of monocrystalline silicon, and the remaining unadsorbed areas will be etched under the action of alkaline solution, which lays the foundation for the formation of pyramids. The nucleating agent in the monocrystalline silicon texturing additive of the present invention selectively adsorbs on high-energy crystal planes such as Si(110), inhibiting their etching rate, while the Si(100) crystal plane is continuously and rapidly etched in an alkaline environment. This difference causes the sides of the formed pyramid structure to be concave inward. The surfactant in the monocrystalline silicon texturing additive of the present invention can reduce the silicon liquid interface energy, causing a "retraction effect" at the sidewalls of the pyramid structure at the etching front, further promoting the formation of the concave morphology on the sides.

[0029] Furthermore, the nucleating agent and dispersing stabilizer in the single-crystal silicon texturing additive of the present invention can form a soluble complex, which accelerates vertical etching and locally blocks lateral etching, thereby causing the Si(100) surface to preferentially indent during the etching process, while the Si(111) surface forms the edge of the pyramid as a slow etching surface, thus promoting the formation of the concave morphology on the side.

[0030] The surfactant in the monocrystalline silicon texturing additive of this invention can effectively regulate the surface tension of the texturing liquid, thereby controlling the desorption rate of bubbles generated during the texturing process within a suitable range, thus ensuring the uniformity and aesthetics of the pyramid textured surface.

[0031] According to a preferred embodiment of the present invention, the alkaline reagent may be one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium acetate, potassium acetate and ammonia water, preferably sodium hydroxide.

[0032] According to a preferred embodiment of the present invention, the nucleating agent is one or more of water-soluble polyethers and water-soluble alcohols. The water-soluble polyethers may be one or more of alkoxy-containing water-soluble polyethers, preferably polyethylene glycol (molecular weight 200-600) and / or propylene glycol block polyethers; the water-soluble alcohols may be one or more of polyhydroxy-containing water-soluble alcohols, preferably polyvinyl alcohol 1799, polyvinyl alcohol 2488, liquid polyvinyl alcohol 0388 and / or liquid polyvinyl alcohol 0599.

[0033] According to a preferred embodiment of the present invention, the nucleating agent is one or more of organic acid salts and alcohols. The organic acid salts may be one or more of cinnamic acid, potassium sorbate, potassium tartrate, and sodium benzoate, preferably potassium tartrate or sodium benzoate. The alcohols may be one or more of ethylene glycol, 1,4-cyclohexanediol, isohexanediol, 1,4-butanediol, and 1,3-propanediol, preferably ethylene glycol or 1,3-propanediol.

[0034] According to a preferred embodiment of the present invention, the surfactant is one or more anionic surfactants, which may be one or more of sodium hexadecyl diphenyl ether sulfonate, sodium dodecyl sulfate, sodium dodecylbenzene sulfonate and sodium alkyl ether polyoxyethylene ether sulfate, preferably sodium hexadecyl diphenyl ether sulfonate and / or sodium alkyl alcohol polyoxyethylene ether sulfate.

[0035] According to a preferred embodiment of the present invention, the chelating agent is one or more multidentate 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 multidentate chelating agent is a chelating agent with multidentate chelating ability.

[0036] According to a preferred embodiment of the present invention, the dispersing stabilizer is one or more water-soluble electrolytes, and the dispersing stabilizer may 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.

[0037] According to a preferred embodiment of the present invention, the monocrystalline silicon texturing additive is used to prepare monocrystalline silicon wafers with a pyramid-like morphology having concave side surfaces.

[0038] On the other hand, the present invention provides a method for preparing a texturing additive for monocrystalline silicon, which includes the following steps:

[0039] (1) Add an electronically pure alkaline reagent to deionized water, stir and dissolve to obtain an alkaline aqueous solution system;

[0040] (2) At room temperature, the nucleating agent is added to the alkaline aqueous solution system, stirred and dissolved at room temperature; then, the nucleating agent is added, stirred evenly at room temperature until clear; then, the surfactant is added, stirred evenly at room temperature until clear; then, the chelating agent is added and stirred evenly until clear; the dispersing stabilizer is added and stirred evenly until clear; finally, the remaining deionized water is added to obtain a single crystal silicon texturing additive.

[0041] On the other hand, the present invention provides a texturing solution for monocrystalline silicon wafers, the texturing solution comprising the monocrystalline 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.

[0042] If the mass ratio of the texturing additive to the alkaline aqueous solution is too high or too low, the nucleating agent cannot be uniformly adsorbed onto the surface of the monocrystalline silicon wafer, thus failing to form uniform masking points. Specifically, if the mass ratio is too high, the nucleating agent content is excessive, resulting in overly dense adsorption points and excessive masking, leading to an overly compact arrangement of the textured pyramid-like structures. Furthermore, because these pyramid-like structures have a certain aspect ratio, they tend to be small and short, hindering the reduction of reflectivity and potentially causing surface reflection. Conversely, if the mass ratio is too low, the nucleating agent content is insufficient, resulting in fewer adsorption points and inadequate masking on the wafer surface. This leads to corrosion of most areas of the wafer, preventing the formation of sufficient pyramid-like morphology and resulting in a textured, uneven, and excessively reflective surface.

[0043] Example

[0044] The embodiments of the present invention employ the following testing methods to test aspect ratio, radius of curvature, and reflectivity performance.

[0045] 1. Test Method

[0046] (1) Aspect Ratio Test

[0047] According to the international standard SEMI PV22-0212 (Guideline for Texturing Silicon Wafer Surfaces), SEM or optical methods are recommended to characterize the textured surface structure for measuring the aspect ratio of this invention. Using a scanning electron microscope (SEM) to directly measure the pyramids on the surface of a single-crystal silicon wafer, cross-sectional images of the pyramids are obtained. The height (h) and base width (w) of each individual pyramid are directly measured, and the aspect ratio AR = h / w is calculated. The test results for each sample are represented by the average range of three measurements.

[0048] (2) Test of radius of curvature

[0049] Using a scanning electron microscope (COXEM Co., Ltd., South Korea) to capture an image of a pyramid structure on the surface of a single-crystal silicon wafer, with the central axis of the pyramid structure as the y-axis and the base of the pyramid as the x-axis, three points—the top, middle, and bottom of the curved arc—are selected. Based on the coordinates of these three points, a function f(x) = y = ax can be fitted to the arc. 2 Given bx + c, calculate the values ​​of a, b, and c.

[0050] Subsequently, according to the curvature k = |y| / (1 + (y) 2 ) 3 / 2 Given the radius of curvature R = 1 / k, differentiating y with respect to y', we get y' = dy / dx. Differentiating y' again yields a fixed value y''. Based on k = y'' / (1 + (y')... 2 ) 3 / 2 By substituting any one of the three points, the radius of curvature R can be calculated.

[0051] After selecting the cross-sectional dimensions (SEM (90 degrees)), three groups of pyramids of different sizes were selected, with two pyramids in each group. The radius of curvature of the side surface of each pyramid was calculated, and then the average value was calculated. The test result of each sample is represented by this average value.

[0052] (3) Test of reflectivity

[0053] The reflectivity of the monocrystalline silicon wafer of this invention is tested according to the standard GB / T 31351-2014 "Test Method for Textured Surface of Crystalline Silicon Solar Cells".

[0054] 2. Preparation Process of Texturing Additive and Single Crystal Silicon Wafer for Examples

[0055] (1) Preparation process of fabrication additives

[0056] Deionized water was added to a mixing tank, and then the alkaline reagent was added to the deionized water. After stirring and dissolving, an alkaline aqueous solution system was obtained. At room temperature, the nucleating agent, nucleating aid, surfactant, chelating agent, and dispersing stabilizer shown in Table 1 were added sequentially to the alkaline aqueous solution system, and stirring was continued. After the previous component was stirred evenly and clarified, the next component was added. Finally, the remaining deionized water was added, and the mixture was stirred evenly to obtain a monocrystalline silicon texturing additive.

[0057] (2) Preparation process of texturing agent

[0058] Prepare a 0.5% sodium hydroxide alkaline aqueous solution. According to the mass ratio of the monocrystalline silicon texturing additive of the present invention to the alkaline aqueous solution of sodium hydroxide, which is 0.2-0.5:100, add the monocrystalline silicon texturing additive of the present invention to the sodium hydroxide alkaline aqueous solution and stir evenly to prepare the texturing solution.

[0059] (3) Fabrication process of single crystal silicon wafers

[0060] The monocrystalline silicon wafer is pre-treated by immersing it in a cleaning solution at 60-65°C in a cleaning tank for 2-5 minutes. After pre-treatment, the wafer is then immersed in an alkaline polishing tank at 70-72°C for 1-3 minutes. The polished wafer is then fed into a spraying device where it is etched by spraying the texturing solution of this invention at 72-75°C for 300-410 seconds. The texturized wafer is then sprayed for cleaning. Finally, the cleaned texturized wafer is dried in a drying chamber to obtain the final monocrystalline silicon wafer.

[0061] 3. Examples 1-9 and Comparative Examples 1-4

[0062] Unless otherwise specified, the raw materials and equipment used in this invention are all commonly used in the field.

[0063] Example 1

[0064] Relative to the total weight of the monocrystalline silicon texturing additive, 20% by mass of deionized water was added to a mixing tank, and 0.1% by mass of sodium hydroxide was added to the deionized water. After stirring and dissolving, an alkaline aqueous solution system was obtained. 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 ethylenediaminetetramethylenephosphonate, and 1.7% by mass of sodium tripolyphosphate were added sequentially to the alkaline aqueous solution system, and stirring was continued. After the previous component was stirred evenly and clarified, the next component was added. Finally, the remaining deionized water was added, and the mixture was stirred evenly to obtain the monocrystalline silicon texturing additive.

[0065] Prepare a 0.5% sodium hydroxide alkaline aqueous solution. Add the monocrystalline silicon texturing additive of the present invention to the sodium hydroxide alkaline aqueous solution according to a mass ratio of 0.5:100. After stirring evenly, a texturing solution is prepared.

[0066] The monocrystalline silicon wafer is pre-treated by immersing it in a cleaning solution at 60-65°C in a cleaning tank for 2-5 minutes. After pre-treatment, the wafer is then immersed in an alkaline polishing tank at 70-72°C for 1-3 minutes. The polished wafer is then fed into a spraying device where it is etched by spraying the texturing solution of this invention at 72-75°C for 300-410 seconds. The texturized wafer is then sprayed for cleaning. Finally, the cleaned texturized wafer is dried in a drying chamber to obtain the final monocrystalline silicon wafer.

[0067] Example 2

[0068] Relative to the total weight of the monocrystalline silicon texturing additive, 20% by mass of deionized water was added to the dosing tank, and 0.1% by mass of sodium hydroxide was added to the deionized water. After stirring and dissolving, an alkaline aqueous solution system was obtained. 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 sequentially to the alkaline aqueous solution system. The remaining steps were the same as in Example 1.

[0069] Example 3

[0070] Relative to the total weight of the monocrystalline silicon texturing additive, 20% by mass of deionized water was added to the dosing tank, and 0.1% by mass of sodium hydroxide was added to the deionized water. After stirring and dissolving, an alkaline aqueous solution system was obtained. 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 sequentially to the alkaline aqueous solution system. The remaining steps were the same as in Example 1.

[0071] Example 4

[0072] Replace 1.9% by mass of polyethylene glycol (molecular weight 600) with 1.9% by mass of polyvinyl alcohol 1799. The remaining steps are the same as in Example 1.

[0073] Example 5

[0074] Replace 1.9% by weight of polyethylene glycol (molecular weight 600) with 1.9% by weight of propylene glycol block polyether. The remaining steps are the same as in Example 1.

[0075] Example 6

[0076] Replace 1.9% by mass of polyethylene glycol (molecular weight 600) with 1.9% by mass of liquid polyvinyl alcohol 0388. The remaining steps are the same as in Example 1.

[0077] Example 7

[0078] Relative to the total weight of the monocrystalline silicon texturing additive, 20% by mass of deionized water was added to the dosing tank, and 0.1% by mass of sodium hydroxide was added to the deionized water. After stirring and dissolving, an alkaline aqueous solution system was obtained. 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 added sequentially to the alkaline aqueous solution system. The remaining steps were the same as in Example 1.

[0079] Example 8

[0080] Relative to the total weight of the monocrystalline silicon texturing additive, 20% by mass of deionized water was added to the dosing tank, and 0.1% by mass of sodium hydroxide was added to the deionized water. After stirring and dissolving, an alkaline aqueous solution system was obtained. 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 ether sulfonate, 1.0% by mass of sodium ethylenediaminetetramethylenephosphonate, and 1.7% by mass of sodium tripolyphosphate were added sequentially to the alkaline aqueous solution system. The remaining steps were the same as in Example 1.

[0081] Example 9

[0082] Relative to the total weight of the monocrystalline silicon texturing additive, 20% by mass of deionized water was added to the dosing tank, and 0.1% by mass of sodium hydroxide was added to the deionized water. After stirring and dissolving, 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-propanediol, 0.17% by mass of sodium alkyl alcohol polyoxyethylene ether sulfate, 1.0% by mass of sodium ethylenediaminetetramethylenephosphonate, 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.

[0083] Comparative Example 1

[0084] Replace 1.9% by mass of polyethylene glycol (molecular weight 600) with 0.5% by mass of polyethylene glycol (molecular weight 600). The remaining steps are the same as in Example 1.

[0085] Comparative Example 2

[0086] Replace 1.9% by mass of polyethylene glycol (molecular weight 600) with 5.8% by mass of polyethylene glycol (molecular weight 600) and 1.6% by mass of potassium tartrate with 0.9% by mass of potassium tartrate. The remaining steps are the same as in Example 1.

[0087] Comparative Example 3

[0088] Replace 1.6% by mass of potassium tartrate with 0.6% by mass of potassium tartrate. The remaining steps are the same as in Example 1.

[0089] Comparative Example 4

[0090] Replace 1.9% by mass of polyethylene glycol (molecular weight 600) with 4.8% by mass of polyethylene glycol (molecular weight 600) and 1.6% by mass of potassium tartrate with 3.5% by mass of potassium tartrate. The remaining steps are the same as in Example 1.

[0091] Table 1. Content of each component in the fabrication additive of the present invention

[0092]

[0093] Table 2. Content of each component in the comparative examples

[0094]

[0095] 4. Effect of Components of Single Crystal Silicon Texturing Additive on Pyramidal Structure and Properties of Textured Surface

[0096] Table 3. Effects of each component in the texturing additive for monocrystalline silicon on the texture and properties of the texturing surface.

[0097]

[0098] As can be seen from the test results of the examples and comparative examples in Tables 1-3:

[0099] As can be seen from Examples 1-6 and Comparative Examples 1-4, the texturing additive of the present invention can obtain a pyramid-like structure with uniform size and concave side surface with a radius of curvature of 7.00-7.50 μm, thereby further reducing the reflectivity of the monocrystalline silicon wafer to 8.1%-8.9%.

[0100] If the nucleating agent content is lower than the content range of the present invention (Comparative Example 1), the pyramid size and radius of curvature on the surface of the obtained monocrystalline silicon wafer will be too large, ultimately resulting in excessively high reflectivity of the monocrystalline silicon wafer. If the nucleating agent content is higher than the content range of the present invention (Comparative Example 2), the pyramid size on the surface of the obtained monocrystalline silicon wafer will be too small and too densely packed, preventing the pyramid-like structures from growing and resulting in a low aspect ratio, also ultimately leading to excessively high reflectivity of the monocrystalline silicon wafer. Furthermore, if the nucleating agent content is higher or lower than the nucleating agent content range of the present invention (Comparative Examples 3 and 4), it will also affect the pyramid-like size and the radius of curvature of the concave side surface of the monocrystalline silicon wafer, thereby causing excessively high reflectivity of the monocrystalline silicon wafer and failing to meet the requirements of the present invention. It can be seen that the effect of the monocrystalline silicon texturing additive of the present invention on the pyramid morphology does not depend on a single component, but rather on the combined effect of the components in specific amounts in the monocrystalline silicon texturing additive, ultimately reducing the reflectivity of the monocrystalline silicon wafer.

[0101] Furthermore, as can be seen from embodiments 7-9 of the present invention, the combined use of multiple nucleating agents or multiple nucleation aids of the present invention can further reduce the reflectivity of monocrystalline silicon wafers while reducing the amount of nucleating agent or nucleation aid added. It is evident that the combined use of multiple nucleating agents and / or multiple nucleation aids of the present invention can further reduce the radius of curvature of the pyramid-like concave side surface of the monocrystalline silicon wafer, thereby further reducing the reflectivity of the monocrystalline silicon wafer.

[0102] In summary, the monocrystalline silicon texturing additive of the present invention can form a pyramid structure with uniform size and concave side surface on the surface of monocrystalline silicon, thereby significantly reducing the reflectivity of monocrystalline silicon wafers.

[0103] The technical solutions of this invention are 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, under the guidance of the specific embodiments or examples described in this invention, can make many improvements and variations without departing from the spirit and scope of the claims. All such improvements and variations fall within the protection scope of this invention.

Claims

1. A texturing additive for monocrystalline silicon, characterized in that, The raw materials for the flocking additive include the following components: Relative to the total weight of the monocrystalline silicon texturing additive, the following components are present: alkaline reagent 0.1%~0.8% by mass, nucleating agent 1.0%~5.0% by mass, nucleation aid 0.8%~3.0% by mass, surfactant 0.012%~0.3% by mass, chelating agent 0.002%~2.0% by mass, dispersing stabilizer 0.001%~6.0% by mass, and the balance being deionized water. The nucleating agent is one or more of polyethylene glycol, propylene glycol block polyether, polyvinyl alcohol 1799, polyvinyl alcohol 2488, liquid polyvinyl alcohol 0388, and liquid polyvinyl alcohol 0599 with a molecular weight of 200-600; the nucleating aid is one or more of potassium tartrate, sodium benzoate, ethylene glycol, and 1,3-propanediol; and the dispersing stabilizer is one or more of sodium tripolyphosphate, sodium hexametaphosphate, and sodium pyrophosphate.

2. The texturing additive for monocrystalline silicon 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 texturing additive for monocrystalline silicon according to any one of claims 1-2, characterized in that, The surfactant is one or more anionic surfactants.

4. The texturing additive for monocrystalline silicon according to any one of claims 1-2, characterized in that, The chelating agent is one or more multidentate chelating agents.

5. The texturing additive for monocrystalline silicon according to any one of claims 1-2, characterized in that, The surfactant is one or both of sodium hexadecyl diphenyl ether sulfonate and sodium alkyl alcohol polyoxyethylene ether sulfate; and / or the chelating agent is one or both of sodium ethylenediaminetetramethylenephosphonate and disodium EDTA.

6. A method for preparing a texturing additive for single-crystal silicon, characterized in that, The method for preparing the texturing additive for monocrystalline silicon according to any one of claims 1-5 includes the following steps: (1) Add the alkaline reagent to deionized water, stir and dissolve to obtain an alkaline aqueous solution system; (2) At room temperature, the nucleating agent, nucleating agent, surfactant, chelating agent, dispersing stabilizer and the balance deionized water are added sequentially to the alkaline aqueous solution system, and the mixture is continuously stirred during the addition of each component to finally obtain a single crystal silicon texturing additive.

7. A texturing solution for monocrystalline silicon wafers, characterized in that, The texturing solution comprises a monocrystalline silicon texturing additive as described in any one of claims 1-5 and an alkaline aqueous solution, wherein the mass ratio of the texturing additive to the alkaline aqueous solution is 0.2-0.5:100.

Images