Low-reflectivity uniform inverted pyramid suede monocrystalline silicon texturing additive and application thereof

Abstract

The invention relates to a low-reflectivity uniform inverted pyramid suede monocrystalline silicon texturing additive and application thereof, and relates to the technical field of solar photovoltaics, and the low-reflectivity uniform inverted pyramid suede monocrystalline silicon texturing additive comprises the following components: hexahydro-1, 3, 4-tris (hydroxyethyl)-s-triazine, alkylphenol polyoxyethylene ether, an organic solvent and a complexing agent. The inverted pyramid textured monocrystalline silicon texturing additive provided by the invention can be applied to a conventional texturing additive process, an inverted pyramid structure can be obtained without adding metal catalysis, and the structure is beneficial to reducing the reflectivity of a silicon wafer, absorbing sunlight to a greater extent and finally improving the photoelectric conversion efficiency of solar energy. Meanwhile, compared with a conventional texturing additive sold in the market, the light trapping performance is superior, the reflectivity of the conventional additive after texturing is 10%-11%, the inverted pyramid textured surface can refract sunlight for multiple times, the reflectivity can be reduced to 7%-9%, and therefore the battery efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of solar photovoltaics, and particularly to a low-reflectivity uniform inverted pyramid textured monocrystalline silicon texturing additive and its application. Background Art

[0002] The power generation of a solar photovoltaic cell is a process of absorbing sunlight and converting it into electrical energy. The reflectivity of the original silicon wafer is above 30%. In order to improve the photoelectric conversion efficiency of monocrystalline silicon solar cells, it is necessary to texture the surface of monocrystalline silicon to etch a textured surface that can absorb sunlight to the maximum extent, so that the incident sunlight is reflected and refracted multiple times on the surface of the monocrystalline silicon wafer, thereby improving the conversion efficiency of the solar cell. At present, the textured surfaces etched by conventional texturing means and the additives used are randomly protruding pyramids. After texturing, the reflectivity of the monocrystalline silicon surface is around 10%. There are also some inverted pyramid textured surfaces whose reflectivity can be further reduced. The current main methods for forming inverted pyramids are optical imprinting technology and etching plans. Among them, etching technology is divided into dry etching and wet etching. Dry etching technology requires harsh environments, needs to be carried out under vacuum conditions and has extremely high costs. Wet etching is mainly a metal deposition method, which has high costs and is difficult to clean. The residual metal ions will cause recombination centers and seriously affect the photoelectric conversion efficiency.

[0003] Patent CN 107955974A mentions a wet chemical etching texturing process for monocrystalline silicon wafers that can form an inverted pyramid textured surface without the catalysis of precious metal ions such as silver and copper. However, the inverted pyramids formed by this process are small and irregular, and there may be a problem that the reduction of the reflectivity of monocrystalline silicon is not obvious. Therefore, it is necessary to develop a uniform inverted pyramid structure with low reflectivity, and this structure can be obtained by a conventional alkaline texturing process. Summary of the Invention

[0004] To solve the above problems, the present invention provides a low-reflectivity uniform inverted pyramid textured monocrystalline silicon texturing additive and its application.

[0005] In a first aspect, the present invention provides a low-reflectivity uniform inverted pyramid textured monocrystalline silicon texturing additive, and the low-reflectivity uniform inverted pyramid textured monocrystalline silicon texturing additive comprises the following components: hydroxyethyl hexahydro-s-triazine, alkylphenol polyoxyethylene ether, organic solvent, and complexing agent.

[0006] Further, in terms of weight percentage, the low-reflectivity uniform inverted pyramid textured monocrystalline silicon texturing additive comprises the following components:

[0007] Hydroxyethyl hexahydro-s-triazine 0.02 - 0.07%, alkylphenol polyoxyethylene ether 1 - 13%, organic solvent 1 - 6%, complexing agent 1 - 10%, and the balance is water.

[0008] Further, the alkylphenol polyoxyethylene ether includes at least one of nonylphenol polyoxyethylene ether and octylphenol polyoxyethylene ether; the organic solvent includes at least one of ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, 1,2-propanediol, diethylene glycol monomethyl ether, and 2-methyl-1,3-propanediol; the complexing agent includes at least one of sodium ethylenediaminetetramethylenephosphonate, diethylenetriamine pentamethylenephosphonate, and amine trimethylenephosphate.

[0009] In a second aspect, the present invention provides an application of the low-reflectivity uniform inverted pyramid textured monocrystalline silicon texturing additive according to any one of the first aspect in texturing the surface of monocrystalline silicon.

[0010] In a third aspect, the present invention provides a low-reflectivity uniform inverted pyramid textured monocrystalline silicon texturing solution, and the low-reflectivity uniform inverted pyramid textured monocrystalline silicon texturing solution contains an alkali solution and the low-reflectivity uniform inverted pyramid textured monocrystalline silicon texturing additive according to any one of the first aspect.

[0011] Further, the weight ratio of the alkali solution to the low-reflectivity uniform inverted pyramid textured monocrystalline silicon texturing additive is (1-5):100, and the alkali solution includes at least one of an aqueous sodium hydroxide solution with a mass fraction of 1-3% and an aqueous potassium hydroxide solution with a mass fraction of 1-3%.

[0012] In a fourth aspect, the present invention provides a method for texturing a low-reflectivity uniform inverted pyramid textured monocrystalline silicon, and the preparation method includes the following steps:

[0013] Using the low-reflectivity uniform inverted pyramid textured monocrystalline silicon texturing additive according to any one of the first aspect, and / or using the low-reflectivity uniform inverted pyramid textured monocrystalline silicon texturing solution according to any one of the second aspect to texture the monocrystalline silicon wafer, to obtain the low-reflectivity uniform inverted pyramid textured monocrystalline silicon.

[0014] Further, the working parameters of the texturing include: the texturing temperature is 75-83°C, and the texturing time is 300-500 s.

[0015] In a fifth aspect, the present invention provides a low-reflectivity uniform inverted pyramid textured monocrystalline silicon, and the low-reflectivity uniform inverted pyramid textured monocrystalline silicon is prepared by using the texturing method according to any one of the fourth aspect; the surface reflectivity of the low-reflectivity uniform inverted pyramid textured monocrystalline silicon is 7%-9%.

[0016] The above technical solutions provided by the embodiments of the present invention have at least the following advantages compared with the prior art:

[0017] 1) The present invention provides a low-reflectivity uniform inverted pyramid textured monocrystalline silicon texturing additive. This inverted pyramid textured monocrystalline silicon texturing additive can be applied to the conventional texturing additive process, and an inverted pyramid structure can be obtained without adding metal catalysts. This structure is beneficial to reducing the reflectivity of the silicon wafer, can absorb sunlight to a greater extent, and ultimately improve the photoelectric conversion efficiency of solar energy. At the same time, compared with the conventional texturing additives sold in the market, it has superior light-trapping performance. After texturing with the conventional additives, the reflectivity is 10%-11%, while the inverted pyramid texture can refract sunlight multiple times, and the reflectivity can be reduced to 7%-9%, thereby improving the battery efficiency.

[0018] 2) The present invention provides a low-reflectivity uniform inverted pyramid textured monocrystalline silicon texturing additive, and the mutual synergistic effects of the components in this inverted pyramid textured monocrystalline silicon texturing additive are as follows:

[0019] As a key substance in the additive, hydroxyethyl hexahydro-s-triazine contains carbon-nitrogen bonds with strong polarity. The Si-H bonds on the surface of the monocrystalline silicon wafer form strong hydrogen bonds with the carbon-nitrogen bonds, and are adsorbed at fixed points on the silicon wafer surface, forming more stable nucleation sites, assisting the strong adsorption and corrosion of the silicon wafer surface by the hydroxyl groups in the alkaline solution; the hydroxyl group structure in hydroxyethyl hexahydro-s-triazine can assist the generated hydrogen to quickly detach from the silicon wafer surface, further accelerating the reaction, and is more conducive to the formation of inverted pyramids.

[0020] Alkylphenol polyoxyethylene ether has strong stability, is resistant to acids and alkalis, and is conducive to stable existence in the texturing alkaline solution; alkylphenol polyoxyethylene ether has good water solubility and wettability, can improve the contact between the texturing alkaline solution and the silicon wafer, is conducive to the uniform progress of the reaction, and ensures the uniform formation of inverted pyramids.

[0021] The complexing agent complexes metal ions and is not easily dissociated, has good chemical stability, and is easily biodegradable.

[0022] 3) On the one hand, applying the texturing additive of the present invention to texture the surface of monocrystalline silicon to obtain a uniform inverted pyramid structure does not require the use of precious metal copper and silver catalysts, and has the characteristics of large-area uniformity and adjustable size. On the other hand, the inverted pyramid structure obtained by applying the texturing additive of the present invention has a low reflectivity, can absorb sunlight more effectively, and is beneficial to improving the photoelectric conversion efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings here are incorporated into the specification and constitute a part of this specification, showing embodiments in line with the present invention, and are used together with the specification to explain the principles of the present invention.

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required for the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0025] Figure 1 This is the SEM top view of the inverted pyramid of the silicon wafer after texturing in Embodiment 2 of the present invention.

[0026] Figure 2 This is the SEM top view of the conventional pyramid of the silicon wafer after texturing in Comparative Example 1 of the present invention.

[0027] Figure 3 This is the SEM top view of the conventional pyramid of the silicon wafer after texturing in Comparative Example 2 of the present invention. Detailed Embodiments

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0029] Unless otherwise specifically stated, various raw materials, reagents, instruments, and equipment used in the present invention can be obtained through market purchases or can be prepared by existing methods.

[0030] In a first aspect, the present invention provides a low-reflectivity uniform inverted pyramid textured monocrystalline silicon texturing additive, and the low-reflectivity uniform inverted pyramid textured monocrystalline silicon texturing additive includes the following components: hydroxyethyl hexahydro-s-triazine, alkylphenol polyoxyethylene ether, organic solvent, and complexing agent.

[0031] The present invention provides a low-reflectivity uniform inverted pyramid textured monocrystalline silicon texturing additive. This inverted pyramid textured monocrystalline silicon texturing additive can be applied to the process of conventional texturing additives. An inverted pyramid structure can be obtained without adding metal catalysts. This structure is beneficial for reducing the reflectivity of the silicon wafer, can absorb sunlight to a greater extent, and ultimately improve the solar photovoltaic conversion efficiency. At the same time, compared with the conventional texturing additives sold in the market, it has superior light-trapping performance. The reflectivity after texturing with conventional additives is 10%-11%, while the inverted pyramid texture can refract sunlight multiple times, and the reflectivity can be reduced to 7%-9%, thereby improving the battery efficiency. The mutual synergistic effects of the components of this inverted pyramid textured monocrystalline silicon texturing additive are as follows:

[0032] As a key substance in the additive, the carbon-nitrogen bonds contained in hydroxyethyl hexahydro-s-triazine have strong polarity. The Si-H bonds on the surface of the monocrystalline silicon wafer form strong hydrogen bonds with the carbon-nitrogen bonds, adsorbing at fixed points on the silicon wafer surface to form more stable nucleation sites, assisting the strong adsorption and corrosion of the silicon wafer surface by the hydroxyl groups in the alkaline solution; the hydroxyl group structure in hydroxyethyl hexahydro-s-triazine can assist the generated hydrogen to quickly detach from the silicon wafer surface, further accelerating the reaction and being more conducive to the formation of inverted pyramids.

[0033] Alkylphenol polyoxyethylene ether has strong stability, is resistant to acids and alkalis, and is conducive to stable existence in the alkaline solution for texturing; alkylphenol polyoxyethylene ether has good water solubility and wettability, can improve the contact between the alkaline solution for texturing and the silicon wafer, and is conducive to the uniform progress of the reaction, ensuring the uniform formation of inverted pyramids.

[0034] The complexing agent complexes metal ions and is not easily dissociated, has good chemical stability, and is easily biodegradable.

[0035] In the present invention, the "low reflectivity" specifically refers to that the surface reflectivity of the inverted pyramid textured monocrystalline silicon obtained after texturing with the inverted pyramid textured monocrystalline silicon texturing additive provided by the present invention can reach 7%-9%.

[0036] In the present invention, the "uniformity" specifically refers to the inverted pyramid textured monocrystalline silicon obtained after texturing with the inverted pyramid textured monocrystalline silicon texturing additive provided by the present invention.

[0037] In some specific embodiments, by weight percentage, the low reflectivity and uniform inverted pyramid textured monocrystalline silicon texturing additive comprises the following components:

[0038] Hydroxyethyl hexahydro-s-triazine 0.02-0.07%, alkylphenol polyoxyethylene ether 1-13%, organic solvent 1-6%, complexing agent 1-10%, and the balance is water.

[0039] In some specific embodiments, the alkylphenol polyoxyethylene ether comprises at least one of nonylphenol polyoxyethylene ether and octylphenol polyoxyethylene ether; the organic solvent comprises at least one of ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, 1,2-propanediol, diethylene glycol monomethyl ether, and 2-methyl-1,3-propanediol; the complexing agent comprises at least one of sodium ethylene diamine tetra(methylene phosphonate), diethylenetriamine penta(methylene phosphonate), and amine trimethylene phosphate.

[0040] In a second aspect, based on a general inventive concept, the present invention provides an application of the low reflectivity and uniform inverted pyramid textured monocrystalline silicon texturing additive according to any one of the first aspect in texturing the surface of monocrystalline silicon.

[0041] On the one hand, by applying the texturing additive of the present invention to texture the surface of monocrystalline silicon, a uniform inverted pyramid structure can be obtained without using precious metals such as copper and silver as catalysts, featuring large-area uniformity and adjustable size. On the other hand, the inverted pyramid structure obtained by applying the texturing additive of the present invention has a low reflectivity, can more effectively absorb sunlight, and is beneficial to improving the photoelectric conversion efficiency.

[0042] In the third aspect, based on the same inventive concept, the present invention provides a texturing solution for monocrystalline silicon with a uniform inverted pyramid texture and low reflectivity, which contains an alkaline solution and the texturing additive for monocrystalline silicon with a uniform inverted pyramid texture and low reflectivity according to any one of the first aspect.

[0043] The texturing solution for monocrystalline silicon with a uniform inverted pyramid texture and low reflectivity provided by the present invention is realized based on the texturing additive for monocrystalline silicon with an inverted pyramid texture according to any one of the first aspect. Therefore, it has at least the beneficial effects described in the first aspect, which will not be elaborated here one by one.

[0044] In some specific embodiments, the weight ratio of the alkaline solution to the texturing additive for monocrystalline silicon with a uniform inverted pyramid texture and low reflectivity is (1 - 5):100, and the alkaline solution includes at least one of an aqueous sodium hydroxide solution with a mass fraction of 1 - 3% and an aqueous potassium hydroxide solution with a mass fraction of 1 - 3%.

[0045] In the fourth aspect, based on the same inventive concept, the present invention provides a method for texturing monocrystalline silicon with a uniform inverted pyramid texture and low reflectivity, and the preparation method includes the following steps:

[0046] Using the texturing additive for monocrystalline silicon with a uniform inverted pyramid texture and low reflectivity according to any one of the first aspect, and / or using the texturing solution for monocrystalline silicon with a uniform inverted pyramid texture and low reflectivity according to any one of the second aspect to texture the monocrystalline silicon wafer, so as to obtain the monocrystalline silicon with a uniform inverted pyramid texture and low reflectivity.

[0047] In some specific embodiments, the working parameters of the texturing include: the texturing temperature is 75 - 83 °C, and the texturing time is 300 - 500 s.

[0048] In the fifth aspect, based on the same inventive concept, the present invention provides a monocrystalline silicon with a uniform inverted pyramid texture and low reflectivity, which is obtained by using the texturing method according to any one of the fourth aspect; the surface reflectivity of the monocrystalline silicon with a uniform inverted pyramid texture and low reflectivity is 7% - 9%.

[0049] It should be noted that without special limitations or explanations, the raw material compounds involved in the present invention can directly use commercially available products or be prepared by oneself according to the existing preparation processes. At the same time, for the preparation process steps of the low-reflectivity uniform inverted pyramid textured monocrystalline silicon texturing additive and the application method steps of the low-reflectivity uniform inverted pyramid textured monocrystalline silicon texturing additive involved in the present invention, without special limitations or specific explanations, they can all be carried out according to the existing technologies, and will not be elaborated one by one in this application document.

[0050] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. The experimental methods without specific conditions noted in the following embodiments are usually determined according to national standards. If there is no corresponding national standard, they are carried out according to general international standards, conventional conditions, or the conditions recommended by the manufacturer.

[0051] Example 1

[0052] The texturing method for obtaining low-reflectivity uniform inverted pyramid textured monocrystalline silicon in this example includes the following process:

[0053] 1) Preparation of texturing additive: Mix 0.02% by mass of hydroxyethyl hexahydro-s-triazine, 3.0% of nonylphenol polyoxyethylene ether, 3.0% of ethylenediaminetetra(methylenephosphonic acid) sodium, 1.5% of organic acid ethylene glycol monomethyl ether and the balance of deionized water to prepare a monocrystalline silicon texturing additive;

[0054] 2) Preparation of alkaline texturing solution: The additive prepared in step 1) is added to the alkaline solution and mixed evenly, where the mass ratio of the texturing additive to the alkali solution is 3.2:100; the alkali solution is a 3.5 wt% aqueous sodium hydroxide solution.

[0055] 3) Texturing method: Put the monocrystalline silicon wafer into the alkaline texturing solution prepared in step 2) for surface texturing, etch the silicon surface to form an inverted pyramid structure, the texturing time is 350 s, and the texturing temperature is 80 °C.

[0056] Example 2

[0057] The texturing method for obtaining low-reflectivity uniform inverted pyramid textured monocrystalline silicon in this example includes the following process:

[0058] 1) Preparation of texturing additive: Mix 0.03% by mass of hydroxyethyl hexahydro-s-triazine, 3.0% of nonylphenol polyoxyethylene ether, 3.0% of ethylenediaminetetra(methylenephosphonic acid) sodium, 1.5% of organic acid diethylene glycol monomethyl ether and the balance of deionized water to prepare a monocrystalline silicon texturing additive;

[0059] 3) Preparation of alkaline texturing solution: The additive prepared in step 1) is added to the alkaline solution and mixed evenly. The mass ratio of the texturing additive to the alkaline solution is 4:100; the alkaline solution is a 3.0 wt% aqueous sodium hydroxide solution.

[0060] 3) Texturing method: The monocrystalline silicon wafer is placed in the alkaline texturing solution prepared in step 2) for surface texturing to etch an inverted pyramid structure on the silicon surface. The texturing time is 400 s and the texturing temperature is 78 °C.

[0061] Example 3

[0062] The texturing method for obtaining a monocrystalline silicon wafer with a low-reflectivity uniform inverted pyramid textured surface in this example includes the following process:

[0063] 1) Preparation of texturing additive: A monocrystalline silicon texturing additive is prepared by mixing 0.05% by mass of hydroxyethyl hexahydro-s-triazine, 3.0% of nonylphenol polyoxyethylene ether, 5.0% of ethylenediamine tetramethylene phosphonic acid sodium, 3.0% of organic acid 2-methyl-1,3-propanediol and the balance of deionized water.

[0064] 4) Preparation of alkaline texturing solution: The additive prepared in step 1) is added to the alkaline solution and mixed evenly. The mass ratio of the texturing additive to the alkaline solution is 3:100; the alkaline solution is a 3.8 wt% aqueous sodium hydroxide solution.

[0065] 3) Texturing method: The monocrystalline silicon wafer is placed in the alkaline texturing solution prepared in step 2) for surface texturing to etch an inverted pyramid structure on the silicon surface. The texturing time is 380 s and the texturing temperature is 81 °C.

[0066] Example 4

[0067] The texturing method for obtaining a monocrystalline silicon wafer with a low-reflectivity uniform inverted pyramid textured surface in this example includes the following process:

[0068] 1) Preparation of texturing additive: A monocrystalline silicon texturing additive is prepared by mixing 0.06% by mass of hydroxyethyl hexahydro-s-triazine, 3.0% of nonylphenol polyoxyethylene ether, 3.0% of amine trimethylene phosphate, 1.5% of organic acid diethylene glycol monomethyl ether and the balance of deionized water.

[0069] 5) Preparation of alkaline texturing solution: The additive prepared in step 1) is added to the alkaline solution and mixed evenly. The mass ratio of the texturing additive to the alkaline solution is 3:100; the alkaline solution is a 3.8 wt% aqueous sodium hydroxide solution.

[0070] 3) Texturing method: The monocrystalline silicon wafer is placed in the alkaline texturing solution prepared in step 2) for surface texturing to etch an inverted pyramid structure on the silicon surface. The texturing time is 380 s and the texturing temperature is 81 °C.

[0071] Comparative Example 1

[0072] The texturing method for obtaining a low-reflectivity uniform inverted pyramid textured monocrystalline silicon in this example includes the following process:

[0073] 1) Preparation of texturing additive: Mix 3.0% nonylphenol polyoxyethylene ether, 3.0% ethylenediaminetetra(methylene phosphonic acid) sodium salt, 1.5% ethylene glycol methyl ether of organic acid and the balance deionized water by mass percentage to prepare a texturing additive for monocrystalline silicon;

[0074] 2) Preparation of alkaline texturing solution: The additive prepared in step 1) is added to the alkaline solution and mixed evenly, where the mass ratio of the texturing additive to the alkali solution is 3.2:100; the alkali solution is a 3.5 wt% aqueous sodium hydroxide solution;

[0075] 3) Texturing method: Put the monocrystalline silicon wafer into the alkaline texturing solution prepared in step 2) for surface texturing, etch an inverted pyramid structure on the silicon surface, the texturing time is 350 s, and the texturing temperature is 80 °C.

[0076] Comparative Example 2

[0077] The texturing method for obtaining a low-reflectivity uniform inverted pyramid textured monocrystalline silicon in this example includes the following process:

[0078] 1) Preparation of texturing additive: Mix 0.02% pyrrolo[2,1-f][1,2,4]triazine-4-amine, 3.0% nonylphenol polyoxyethylene ether, 3.0% ethylenediaminetetra(methylene phosphonic acid) sodium salt, 1.5% ethylene glycol methyl ether of organic acid and the balance deionized water by mass percentage to prepare a texturing additive for monocrystalline silicon;

[0079] 2) Preparation of alkaline texturing solution: The additive prepared in step 1) is added to the alkaline solution and mixed evenly, where the mass ratio of the texturing additive to the alkali solution is 3.2:100; the alkali solution is a 3.5 wt% aqueous sodium hydroxide solution;

[0080] 3) Texturing method: Put the monocrystalline silicon wafer into the alkaline texturing solution prepared in step 2) for surface texturing, etch an inverted pyramid structure on the silicon surface, the texturing time is 350 s, and the texturing temperature is 80 °C.

[0081] Test Example

[0082] In this example, the performance of the monocrystalline silicon wafers after texturing treatment in the above examples and comparative examples was tested, and the test results are shown in Table 1.

[0083] 1) Test of surface reflectivity: Use a D8 reflectivity instrument.

[0084] 2) Test of surface uniformity: Scan the pyramid uniformity by SEM.

[0085] Table 1 Reflectivity Results of Monocrystalline Silicon Wafers after Texturing Treatment in Examples and Comparative Examples

[0086] Group Reflectance after texturing % Example 1 9.00 Example 2 8.85 Example 3 8.23 Example 4 8.00 Comparative Example 1 10.56 Comparative Example 2 10.53

[0087] As can be seen from the results in Table 1, the reflectivities of Examples 1 - 4 are all more than 1 point lower than that of Comparative Example 1, indicating that the light trapping effect of the inverted pyramid is far superior to that of Comparative Example 1.

[0088] In addition, the SEM top view of the inverted pyramid of the silicon wafer after texturing in Example 2 of the present invention is as shown in Figure 1 shown, and the SEM top view of the conventional pyramid of the silicon wafer after texturing in Comparative Example 1 is as shown in Figure 2 shown, and the SEM top view of the conventional pyramid of the silicon wafer after texturing in Comparative Example 2 is as shown in Figure 3 shown. Through the comparison of Figure 1 and Figure 2 , it can be known that the inverted pyramid structure cannot be formed without hydroxyethyl hexahydro - s - triazine; through the comparison of Figure 1 and Figure 3 , it can also be known that the homologues of hydroxyethyl hexahydro - s - triazine cannot achieve the inverted pyramid structure either.

[0089] In summary, the present invention provides a low - reflectivity uniform inverted pyramid textured surface monocrystalline silicon texturing additive and its application. The inverted pyramid textured surface monocrystalline silicon texturing additive provided by the present invention can be applied to the process of conventional texturing additives, and the inverted pyramid structure can be obtained without adding metal catalysts. This structure is beneficial to reducing the reflectivity of the silicon wafer, can absorb sunlight to a greater extent, and ultimately improve the photoelectric conversion efficiency of solar energy. At the same time, compared with the conventional texturing additives on the market, it has superior light trapping performance. The reflectivity after texturing with conventional additives is 10% - 11%, while the inverted pyramid textured surface can refract sunlight multiple times, and the reflectivity can be reduced to 7% - 9%, thereby improving the battery efficiency.

[0090] The various embodiments of the present invention may exist in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be construed as a rigid limitation on the scope of the present invention; therefore, it should be considered that the range description has specifically disclosed all possible sub - ranges and the individual values within the range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub - ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and the individual numbers within the range, such as 1, 2, 3, 4, 5, and 6, which applies regardless of the range. Additionally, whenever a numerical range is indicated herein, it means including any cited number (fraction or integer) within the indicated range.

[0091] The above are only specific embodiments of the present invention, enabling those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather will conform to the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A low-reflectivity uniform inverted pyramid texture single-crystalline silicon texturing additive, characterized in that, The low-reflectivity uniform inverted pyramid texture single-crystalline silicon texturing additive comprises the following components: hydroxyethyl hexahydro-s-triazine, alkylphenol polyoxyethylene ether, organic solvent, and complexing agent.

2. The low-reflectivity uniform inverted pyramid textured monocrystalline silicon texturing additive according to claim 1, wherein By weight percentage, the low-reflectivity uniform inverted pyramid texture single-crystalline silicon texturing additive comprises the following components: hydroxyethyl hexahydro-s-triazine 0.02-0.07%, alkylphenol polyoxyethylene ether 1-13%, organic solvent 1-6%, complexing agent 1-10%, and the balance is water.

3. The low-reflectivity uniform inverted pyramid textured monocrystalline silicon texturing additive according to any one of claims 1 to 2, characterized in that, The alkylphenol polyoxyethylene ether includes at least one of nonylphenol polyoxyethylene ether and octylphenol polyoxyethylene ether; the organic solvent includes at least one of ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, 1,2-propanediol, diethylene glycol monomethyl ether, and 2-methyl-1,3-propanediol; the complexing agent includes at least one of sodium ethylenediamine tetramethylenephosphonate, diethylenetriamine pentamethylenephosphonate, and amine trimethylenephosphate.

4. Application of the low-reflectivity uniform inverted pyramid texture single-crystalline silicon texturing additive according to any one of claims 1 to 3 in texturing the surface of single-crystalline silicon.

5. A texturing solution for low-reflectivity uniform inverted pyramid textured monocrystalline silicon, characterized in that, The low-reflectivity uniform inverted pyramid texture single-crystalline silicon texturing solution contains an alkali solution and the low-reflectivity uniform inverted pyramid texture single-crystalline silicon texturing additive according to any one of claims 1 to 3.

6. The low-reflectivity uniform inverted pyramid textured monocrystalline silicon texturing solution according to claim 5, wherein The weight ratio of the alkali solution to the low-reflectivity uniform inverted pyramid texture single-crystalline silicon texturing additive is (1-5):100, and the alkali solution includes at least one of an aqueous sodium hydroxide solution with a mass fraction of 1-3% and an aqueous potassium hydroxide solution with a mass fraction of 1-3%.

7. A method for making velvet single-crystalline silicon with a uniform inverted pyramid and low reflectivity, characterized in that, The preparation method comprises the following steps: Using the low-reflectivity uniform inverted pyramid texture single-crystalline silicon texturing additive according to any one of claims 1 to 3, and / or using the low-reflectivity uniform inverted pyramid texture single-crystalline silicon texturing solution according to claim 5 or 6 to texture a single-crystalline silicon wafer to obtain the low-reflectivity uniform inverted pyramid texture single-crystalline silicon.

8. The texturing method according to claim 7, characterized in that The working parameters of the texturing include: the texturing temperature is 75-83 °C, and the texturing time is 300-500 s.

9. A uniform inverted pyramid textured monocrystalline silicon with a low reflectivity, characterized in that, The low-reflectivity uniform inverted pyramid texture single-crystalline silicon is obtained by the texturing method according to claim 7 or claim 8; the surface reflectivity of the low-reflectivity uniform inverted pyramid texture single-crystalline silicon is 7%-9%.

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