A texturing additive suitable for preparing homogeneous crack textured monocrystalline silicon and its application method

Abstract

This invention discloses a texturing additive and its application method suitable for preparing homogeneous textured monocrystalline silicon, relating to the field of monocrystalline silicon solar cell manufacturing technology. It comprises the following components in weight percentage: 0.5-1% texturing nucleating agent; 0.02-2% defoamer; 0.1-0.5% auxiliary nucleating agent; 0.1-1% surfactant; 0.23-1.3% other functional components; and the balance being deionized water; the total content of all components is 100%. The other functional components are a mixture of heavy metal chelating stabilizer, silanol passivating protectant, dispersing synergist, morphology modifier, and rhamnose glycolipid in a weight ratio of (0.5-3):(0.8-4):(0.4-2.5):(0.6-3):(0.3-2). This additive can synergistically induce homogeneous cracking of pyramids, reduce silicon wafer reflectivity, and increase the specific surface area of ​​the pyramids.

Description

Technical Field

[0001] This invention relates to the field of monocrystalline silicon solar cell manufacturing technology, and in particular to a texturing additive suitable for preparing monocrystalline silicon with a uniformly cracked textured surface and its application method. Background Technology

[0002] Monocrystalline silicon wafers are the core substrate for photovoltaic cells and semiconductor devices, and the uniformity of their surface texture directly affects light absorption efficiency and device performance. The current mainstream texturing process is alkaline texturing, which involves anisotropic etching of the silicon wafer with alkaline solutions such as sodium hydroxide and potassium hydroxide to form a pyramidal textured surface. However, traditional alkaline texturing has significant drawbacks: firstly, the etching rate is greatly affected by the silicon wafer's crystal orientation and surface defects, easily leading to localized over- or under-etching, resulting in poor texture uniformity; secondly, conventional additives such as isopropanol and polyethylene glycol can only suppress the etching rate to a limited extent and cannot precisely control the homogeneous crack morphology of the textured surface, making it difficult to meet the requirements of high-efficiency photovoltaic cells for ultra-uniform textured surfaces.

[0003] As the conversion efficiency of photovoltaic cells continues to improve, the industry's requirements for the textured surface of monocrystalline silicon wafers have upgraded from a "pyramid structure" to a "uniformly cracked texture." A uniformly cracked texture refers to a textured surface where the size, depth, and density of the pits formed by corrosion are highly consistent, with no obvious crystal orientation preference. This structure can maximize the reduction of light reflectivity while improving carrier collection efficiency. However, existing texturing systems struggle to achieve this goal: the corrosion selectivity of a single alkaline solution depends on the difference in bond energy between crystal plane atoms, making it impossible to eliminate corrosion inhomogeneity caused by crystal orientation; most existing additives can only slow down the overall corrosion rate through adsorption, and cannot specifically regulate the corrosion kinetics of different crystal planes.

[0004] It is evident that developing a texturing additive that can induce uniform cracking in the pyramid structure, further reduce reflectivity, and increase specific surface area, along with its application method, is of significant technical and industrial value for overcoming the performance bottlenecks of existing texturing technologies and improving the photoelectric conversion efficiency of monocrystalline silicon solar cells. Summary of the Invention

[0005] The main objective of this invention is to overcome the shortcomings of the prior art and provide a texturing additive and its application method suitable for preparing homogeneous cracked textured monocrystalline silicon. This texturing additive is fully compatible with existing production lines and can synergistically induce uniform cracking of pyramids, reduce silicon wafer reflectivity, suppress metal recombination loss, stabilize the textured storage morphology, extend the service life of the texturing tank, and eliminate over-etching defects at the edges of thin silicon wafers.

[0006] To achieve the above objectives, the present invention provides a texturing additive suitable for preparing homogeneous cracked textured monocrystalline silicon, comprising the following components in weight percentage: Nucleating agent for suede surface: 0.5-1%; Defoamer 0.02-2%; Nucleation aid 0.1-0.5%; Surfactant 0.1-1%; Other functional components: 0.23-1.3%; The remainder is deionized water; the total content of the above components is 100%; the other functional components are heavy metal chelating stabilizers, silanol passivating protectants, dispersing synergists, morphology regulators, and rhamnolipids compounded in a mass ratio of (0.5-3):(0.8-4):(0.4-2.5):(0.6-3):(0.3-2).

[0007] Preferably, the nucleating agent for the velvet surface is one or more of the following: brown algae polyphenols, water-soluble chitosan, sodium polyacrylate, and cyclodextrin.

[0008] Preferably, the water-soluble chitosan has a degree of deacetylation ≥90% and a weight-average molecular weight of 200,000; the cyclodextrin is technical-grade hydroxypropyl β-cyclodextrin with a molar degree of substitution of 0.5-1, provided by Shandong Binzhou Zhiyuan Biotechnology Co., Ltd.; and the sodium polyacrylate has a weight-average molecular weight of 5100.

[0009] Preferably, the defoamer is one or more of sucrose and sodium alginate.

[0010] Preferably, the auxiliary nucleating agent is one or more of tartaric acid, sodium citrate, glycerol polyether, and anthocyanin; the glycerol polyether is glycerol polyoxyethylene ether G-18.

[0011] Preferably, the surfactant is one or more of PEG-200, PEG-400, PEG-600, fluorocarbon surfactant, and AEO-9; the fluorocarbon surfactant is designated as FHJ-633.

[0012] Preferably, the heavy metal chelating stabilizer is a compound of disodium EDTA, sodium gluconate, and phytic acid in a mass ratio of 1:(0.8-1.2):(1-2).

[0013] Preferably, the silanol passivation agent is at least one of mannitol, sorbitol, and xylitol.

[0014] Preferably, the dispersing synergist is polyglutamic acid with a molecular weight of 10 kDa-2000 kDa, provided by Nanjing Xuankai Biotechnology Co., Ltd.

[0015] Preferably, the morphology regulator is fructooligosaccharide 95 powder, provided by Shandong Bailong Chuangyuan Biotechnology Co., Ltd.

[0016] Another objective of this invention is to provide a method for preparing the texturing additive suitable for preparing homogeneous cracked textured monocrystalline silicon, comprising the following steps: mixing each component evenly according to the weight parts, stirring continuously at 200-220 r / min for 25-35 min; then letting it stand for 25-35 min, circulating and filtering it 2-4 times using a 0.2 μm aqueous filter membrane, sealing and dispensing the filtrate in plastic buckets, and storing it at room temperature away from light to obtain the finished texturing additive.

[0017] Another object of the present invention is to provide a method for using the texturing additive suitable for preparing homogeneous crack textured monocrystalline silicon, comprising the following steps: Step S1, One-step texturing: Place the monocrystalline silicon wafer in the first alkaline texturing solution and react at 70-90℃ for 200-500 seconds to form a pyramid structure on the surface of the silicon wafer. Step S2, Water washing: The silicon wafer after texturing in step S1 is washed with deionized water at 20-30℃ for 115-125 seconds. Step S3, two-step texturing: The silicon wafer cleaned in step S2 is placed in the second alkaline texturing solution and reacted at 50-80℃ for 50-300 seconds. Step S4, Post-processing: The silicon wafer after texturing in step S3 is washed with deionized water at 20-30℃ for 115-125 seconds and then dried.

[0018] Preferably, the first alkaline texturing solution in step S1 is made of the following components by weight percentage: 0.1% to 2% of the first step texturing additive, 0.5% to 3% of the alkali, and the balance being deionized water; the alkali is one or both of sodium hydroxide and potassium hydroxide; the brand of the first step texturing additive is JUNHE®2550.

[0019] Preferably, the second alkaline texturing solution in step S3 is made of the following components by weight percentage: 0.1%-2% of the second-step texturing additive, 0.1%-2% of the alkali, and the balance being deionized water, wherein the alkali is one or both of sodium hydroxide or potassium hydroxide; the second-step texturing additive is the above-mentioned texturing additive suitable for preparing homogeneous cracked textured monocrystalline silicon.

[0020] Preferably, the drying temperature in step S4 is 80-100℃ and the drying time is 400-800 seconds.

[0021] Due to the application of the above technical solution, the present invention has the following beneficial effects: (1) The texturing additive and its application method disclosed in this invention are suitable for preparing homogeneous cracked textured monocrystalline silicon. The additive uses a multi-component compounded functional texturing additive in combination with a two-step segmented alkaline texturing process. Through the synergistic coupling effect of the nucleating agent, the auxiliary nucleating agent and the morphology control agent, the initial pyramid structure on the silicon wafer surface can be actively induced to be uniformly cracked, the crystal orientation corrosion preference can be weakened, and the size, depth and nucleation density of the textured pits can be precisely controlled. This solves the problems of excessive local corrosion and uneven corrosion in traditional processes, and achieves the formation of a uniform cracked textured structure on the whole wafer, which greatly improves the overall uniformity of the textured surface of the monocrystalline silicon wafer.

[0022] (2) The texturing additive and its application method disclosed in this invention, suitable for preparing homogeneous textured monocrystalline silicon, employs a formulation system of surfactants, dispersants, and defoamers in a synergistic manner. This optimizes the surface tension and solution dispersion stability of the texturing solution. Compared with conventional single additives such as isopropanol and polyethylene glycol, it allows the texturing solution to spread evenly on the silicon wafer surface without any residual bubbles, ensuring that the etching reaction proceeds stably and synchronously throughout the entire process. Simultaneously, the bio-activation synergistic effect of rhamnolipids effectively increases the specific surface area of ​​the silicon wafer on the basis of uniform etching, further reducing the surface light reflectivity of the silicon wafer and maximizing the capture of incident light sources. This provides core structural support for improving the photoelectric conversion efficiency of monocrystalline silicon solar cells, overcoming the shortcomings of traditional texturing processes, such as a single textured surface structure and limited anti-reflection effect.

[0023] (3) The texturing additive and its application method disclosed in this invention, applicable to the preparation of homogeneous textured monocrystalline silicon, employs a composite functional combination of a heavy metal chelating stabilizer and a silanol passivating protectant to form a dual protective synergistic effect. This effectively chelates trace heavy metal impurities in the texturing solution, avoiding carrier recombination losses caused by impurities. Simultaneously, it passivates the active silanol groups on the silicon wafer surface, inhibiting surface oxidation and morphological changes after texturing, effectively stabilizing the storage morphology of the homogeneous textured surface, and improving the stability and yield of the finished silicon wafer. Furthermore, this compound component can reduce the deposition of impurities in the texturing tank and the rate of alkaline degradation during the texturing process, significantly extending the service life of the texturing tank and reducing the cost of replacement and maintenance of consumables in the production line.

[0024] (4) The texturing additive and its application method disclosed in this invention, applicable to the preparation of homogeneous cracked textured monocrystalline silicon, adopts a segmented, dual-system texturing solution with step-by-step etching process. Combined with the targeted regulation characteristics of the special homogeneous cracking additive, it can effectively match the etching requirements of the two core stages of pyramid forming and homogeneous cracking. The first step forms the pyramid substrate, and the second step achieves structural homogeneous cracking modification. The two processes complement each other and can specifically solve the technical problems of edge stress concentration and over-etching of thin silicon wafers, effectively reducing the edge damage and morphological defects of thin silicon wafers, and meeting the high-efficiency texturing production requirements of ultra-thin silicon wafers.

[0025] (5) The texturing additive and its usage method disclosed in this invention, applicable to the preparation of homogeneous crack textured monocrystalline silicon, wherein the other functional components are a heavy metal chelating stabilizer, a silanol passivating protectant, a dispersing synergist, a morphology modifier, and rhamnolipids in a mass ratio of (0.5-3):(0.8-4):(0.4-2.5):(0.6-3):(0.3-2). The morphology modifier and the dispersing synergistically optimize the uniformity of texturing corrosion, meeting the requirements of homogeneous crack textured surface forming; the rhamnolipids can further improve the overall dispersion and wetting performance of the additives, assisting in refining the microstructure of the textured surface; the heavy metal chelating stabilizer can remove harmful impurities from the texturing system in real time, avoiding interference from impurities on textured surface forming; the silanol passivating protectant simultaneously locks the formed textured surface structure. The five components each perform their respective functions and mutually enhance each other, forming a multi-dimensional gain effect from corrosion control, impurity removal, structural protection, and interface optimization, effectively improving the stability, accuracy, and adaptability of the texturing system. Attached Figure Description

[0026] Fig. 1 This is a top-view SEM image of the pyramid on the surface of a texturized silicon wafer provided in Embodiment 1 of the present invention.

[0027] Fig. 2 This is a top-view SEM image of the pyramid on the surface of a texturized silicon wafer provided in Embodiment 2 of the present invention.

[0028] Fig. 3 This is a top-view SEM image of the pyramid on the surface of a texturized silicon wafer provided in Embodiment 3 of the present invention. Detailed Implementation

[0029] See attached diagram. Figs. 1-3 Scanning electron microscopy (SEM) revealed that the surface of the silicon wafer pyramid structure after texturing with the texturing additives provided in Examples 1-3 of this invention exhibits multiple interconnected pyramidal structures, with uniform cracking characteristics on the pyramidal surface. This microstructure significantly reduces reflectivity by inducing multiple refractions and scatterings of light.

[0030] Example 1: A texturing additive suitable for preparing homogeneous crack textured monocrystalline silicon, composed of the following components in weight percentage: Nucleating agent for suede surface: 0.5%; Defoamer 0.02%; Nucleation aid 0.1%; Surfactant 0.1%; Other functional components: 0.23%; The remainder is deionized water; the total content of the above components is 100%; the other functional components are heavy metal chelating stabilizers, silanol passivating protectants, dispersing synergists, morphology regulators, and rhamnolipids compounded in a mass ratio of 0.5:0.8:0.4:0.6:0.3; the velvety nucleating agent is brown algae polyphenols.

[0031] The defoamer is sucrose; the nucleating agent is tartaric acid; the surfactant is PEG-200; the heavy metal chelating stabilizer is a mixture of disodium EDTA, sodium gluconate, and phytic acid in a mass ratio of 1:0.8:1; the silanol passivating protectant is mannitol; the dispersing synergist is polyglutamic acid with a molecular weight of 10 kDa-2000 kDa, provided by Nanjing Xuankai Biotechnology Co., Ltd.; and the morphology regulator is fructooligosaccharide 95 powder, provided by Shandong Bailong Chuangyuan Biotechnology Co., Ltd.

[0032] A method for preparing a texturing additive suitable for preparing homogeneous cracked textured monocrystalline silicon includes the following steps: mixing each component evenly according to the weight parts, stirring continuously at 200 r / min for 25 min; then letting it stand for 25 min, filtering twice using a 0.2 μm aqueous filter membrane, sealing the filtrate in plastic buckets, and storing it at room temperature away from light to obtain the finished texturing additive.

[0033] A method of using the texturing additive suitable for preparing homogeneous crack textured monocrystalline silicon includes the following steps: Step S1, One-step texturing: Place the monocrystalline silicon wafer in the first alkaline texturing solution and react at 70°C for 200 seconds to form a pyramid structure on the surface of the silicon wafer; Step S2, Water washing: The silicon wafer after texturing in step S1 is washed with deionized water at 20°C for 115 seconds. Step S3, two-step texturing: The silicon wafer cleaned in step S2 is placed in the second alkaline texturing solution and reacted at 50°C for 50 seconds. Step S4, Post-processing: The silicon wafer after texturing in step S3 is washed with deionized water at 20°C for 115 seconds and then dried.

[0034] The first alkaline texturing solution in step S1 is made of the following components by weight percentage: 0.1% of the first step texturing additive, 0.5% of the alkali, and the balance being deionized water; the alkali is sodium hydroxide; the grade of the first step texturing additive is JUNHE®2550.

[0035] In step S3, the second alkaline texturing solution is made of the following components by weight percentage: 0.1% of the second-step texturing additive, 0.1% of the alkali, and the balance being deionized water, wherein the alkali is sodium hydroxide; the second-step texturing additive is the above-mentioned texturing additive suitable for preparing monocrystalline silicon with a uniformly cracked textured surface; the drying temperature in step S4 is 80°C, and the drying time is 400 seconds.

[0036] Example 2: A texturing additive suitable for preparing homogeneous cracked textured monocrystalline silicon, composed of the following components in weight percentage: 0.6% nucleating agent for suede surface; Defoamer 0.5%; Nucleating agent 0.2%; Surfactant 0.3%; Other functional components: 0.4%; The remainder is deionized water; the total content of all the above components is 100%; the other functional components are heavy metal chelating stabilizers, silanol passivating protectants, dispersing synergists, morphology modifiers, and rhamnolipids compounded in a mass ratio of 1:2:1:1:0.6; the textured nucleating agent is water-soluble chitosan; the degree of deacetylation of the water-soluble chitosan is ≥90%, and the weight-average molecular weight is 200,000.

[0037] The defoamer is sodium alginate; the nucleating agent is sodium citrate; the surfactant is PEG-400; the heavy metal chelating stabilizer is a mixture of disodium EDTA, sodium gluconate, and phytic acid in a mass ratio of 1:0.9:1.3; the silanol passivating protectant is sorbitol; the dispersing synergist is polyglutamic acid with a molecular weight of 10 kDa-2000 kDa, provided by Nanjing Xuankai Biotechnology Co., Ltd.; and the morphology regulator is fructooligosaccharide 95 powder, provided by Shandong Bailong Chuangyuan Biotechnology Co., Ltd.

[0038] A method for preparing a texturing additive suitable for preparing homogeneous cracked textured monocrystalline silicon includes the following steps: mixing each component evenly according to the weight parts, stirring continuously at 205 r / min for 27 min; then letting it stand for 28 min, filtering it three times using a 0.2 μm aqueous filter membrane, sealing the filtrate in plastic buckets, and storing it at room temperature away from light to obtain the finished texturing additive.

[0039] A method of using the texturing additive suitable for preparing homogeneous crack textured monocrystalline silicon includes the following steps: Step S1, One-step texturing: Place the monocrystalline silicon wafer in the first alkaline texturing solution and react at 75°C for 300 seconds to form a pyramid structure on the surface of the silicon wafer. Step S2, Water washing: The silicon wafer after texturing in step S1 is washed with deionized water at 23°C for 118 seconds. Step S3, two-step texturing: The silicon wafer cleaned in step S2 is placed in the second alkaline texturing solution and reacted at 60°C for 100 seconds. Step S4, Post-processing: The silicon wafer after texturing in step S3 is washed with deionized water at 23°C for 118 seconds and then dried.

[0040] The first alkaline texturing solution in step S1 is made of the following components by weight percentage: 0.6% of the first step texturing additive, 1% of the alkali, and the balance being deionized water; the alkali is potassium hydroxide; the grade of the first step texturing additive is JUNHE®2550.

[0041] In step S3, the second alkaline texturing solution is made of the following components by weight percentage: 0.8% of the second-step texturing additive, 0.8% of the alkali, and the balance being deionized water, wherein the alkali is potassium hydroxide; the second-step texturing additive is the above-mentioned texturing additive suitable for preparing monocrystalline silicon with a uniformly cracked textured surface; the drying temperature in step S4 is 85°C and the drying time is 500 seconds.

[0042] Example 3: A texturing additive suitable for preparing homogeneous crack textured monocrystalline silicon, composed of the following components in weight percentage: 0.8% nucleating agent for suede surface; Defoamer 1.3%; Nucleation aid 0.3%; Surfactant 0.6%; Other functional components: 0.8%; The remainder is deionized water; the total content of all the above components is 100%; the other functional components are a mixture of heavy metal chelating stabilizer, silanol passivating protectant, dispersing synergist, morphology modifier, and rhamnose glycolipid in a mass ratio of 2:2.5:1.6:1.5:1.2; the textured nucleating agent is sodium polyacrylate; the weight average molecular weight of the sodium polyacrylate is 5100; the defoamer is sucrose; the auxiliary nucleating agent is glycerol polyether; the glycerol polyether is glycerol polyoxyethylene ether. G-18; the surfactant is PEG-600; the heavy metal chelating stabilizer is a mixture of disodium EDTA, sodium gluconate, and phytic acid in a mass ratio of 1:1:1.5; the silanol passivation protectant is xylitol; the dispersing synergist is polyglutamic acid with a molecular weight of 10 kDa-2000 kDa, provided by Nanjing Xuankai Biotechnology Co., Ltd.; the morphology regulator is fructooligosaccharide 95 powder, provided by Shandong Bailong Chuangyuan Biotechnology Co., Ltd.

[0043] A method for preparing a texturing additive suitable for preparing homogeneous cracked textured monocrystalline silicon includes the following steps: mixing each component evenly according to the weight parts, stirring continuously at 210 r / min for 30 min; then letting it stand for 30 min, filtering it three times using a 0.2 μm aqueous filter membrane, sealing the filtrate in plastic buckets, and storing it at room temperature away from light to obtain the finished texturing additive.

[0044] A method of using the texturing additive suitable for preparing homogeneous crack textured monocrystalline silicon includes the following steps: Step S1, One-step texturing: Place the monocrystalline silicon wafer in the first alkaline texturing solution and react at 80°C for 350 seconds to form a pyramid structure on the surface of the silicon wafer; Step S2, Water washing: The silicon wafer after texturing in step S1 is washed with deionized water at 25°C for 120 seconds. Step S3, two-step texturing: The silicon wafer cleaned in step S2 is placed in the second alkaline texturing solution and reacted at 65°C for 180 seconds. Step S4, Post-processing: The silicon wafer after texturing in step S3 is washed with deionized water at 25°C for 120 seconds and then dried.

[0045] In step S1, the first alkaline texturing solution comprises the following components by weight percentage: 1.2% of the first-step texturing additive, 2% of the alkali, and the balance being deionized water; the alkali is sodium hydroxide; the grade of the first-step texturing additive is JUNHE®2550; In step S3, the second alkaline texturing solution comprises the following components by weight percentage: 1% of the second-step texturing additive, 1.3% of the alkali, and the balance being deionized water; the alkali is sodium hydroxide; the second-step texturing additive is the above-mentioned texturing additive suitable for preparing homogeneous cracked textured monocrystalline silicon; In step S4, the drying temperature is 90°C and the drying time is 600 seconds.

[0046] Example 4: A texturing additive suitable for preparing homogeneous crack textured monocrystalline silicon, composed of the following components in weight percentage: 0.9% nucleating agent for suede surface; Defoamer 1.8%; Nucleation aid 0.4%; Surfactant 0.8%; Other functional components: 1.1%; The remainder is deionized water; the total content of all the above components is 100%; the other functional components are heavy metal chelating stabilizers, silanol passivating protectants, dispersing synergists, morphology regulators, and rhamnolipids in a mass ratio of 2.5:3.5:2.3:2.5:1.5; the textured nucleating agent is a mixture of brown algae polyphenols, water-soluble chitosan, sodium polyacrylate, and cyclodextrin in a mass ratio of 1:0.8:0.5:1; the water-soluble chitosan has a degree of deacetylation ≥90% and a weight-average molecular weight of 200,000; the cyclodextrin is technical-grade hydroxypropyl β-cyclodextrin with a molar substitution degree of 0.5-1, provided by Shandong Binzhou Zhiyuan Biotechnology Co., Ltd.; the sodium polyacrylate has a weight-average molecular weight of 5100.

[0047] The defoamer is a mixture of sucrose and sodium alginate in a mass ratio of 1:2; the nucleating agent is a mixture of tartaric acid, sodium citrate, glycerol polyether, and anthocyanins in a mass ratio of 0.8:1:1:2; the glycerol polyether is glycerol polyoxyethylene ether G-18; the surfactant is a mixture of PEG-200, PEG-400, PEG-600, fluorocarbon surfactant, and AEO-9 in a mass ratio of 1:2:1:0.8:1; the fluorocarbon surfactant is designated as FHJ. -633; the heavy metal chelating stabilizer is a compound of disodium EDTA, sodium gluconate, and phytic acid in a mass ratio of 1:1.1:1.8; the silanol passivation protectant is a compound of mannitol, sorbitol, and xylitol in a mass ratio of 1:2:3; the dispersing synergist is polyglutamic acid with a molecular weight of 10 kDa-2000 kDa, provided by Nanjing Xuankai Biotechnology Co., Ltd.; the morphology regulator is fructooligosaccharide 95 powder, provided by Shandong Bailong Chuangyuan Biotechnology Co., Ltd.

[0048] A method for preparing a texturing additive suitable for preparing homogeneous cracked textured monocrystalline silicon includes the following steps: mixing each component evenly according to the weight parts, stirring continuously at 215 r / min for 33 min; then letting it stand for 33 min, filtering it four times using a 0.2 μm aqueous filter membrane, sealing the filtrate in plastic buckets, and storing it at room temperature away from light to obtain the finished texturing additive.

[0049] A method of using the texturing additive suitable for preparing homogeneous crack textured monocrystalline silicon includes the following steps: Step S1, One-step texturing: Place the monocrystalline silicon wafer in the first alkaline texturing solution and react at 85°C for 450 seconds to form a pyramid structure on the surface of the silicon wafer. Step S2, Water washing: The silicon wafer after texturing in step S1 is washed with deionized water at 28°C for 123 seconds. Step S3, two-step texturing: The silicon wafer cleaned in step S2 is placed in the second alkaline texturing solution and reacted at 75°C for 250 seconds. Step S4, Post-processing: The silicon wafer after texturing in step S3 is washed with deionized water at 28°C for 123 seconds and then dried.

[0050] In step S1, the first alkaline texturing solution comprises the following components by weight percentage: 1.8% of the first-step texturing additive, 2.5% of the alkali, and the balance being deionized water; the alkali is sodium hydroxide; the grade of the first-step texturing additive is JUNHE®2550; In step S3, the second alkaline texturing solution comprises the following components by weight percentage: 1.8% of the second-step texturing additive, 1.8% of the alkali, and the balance being deionized water, the alkali being sodium hydroxide; the second-step texturing additive is the above-mentioned texturing additive suitable for preparing homogeneous cracked textured monocrystalline silicon; In step S4, the drying temperature is 95°C, and the drying time is 750 seconds.

[0051] Example 5: A texturing additive suitable for preparing homogeneous crack textured monocrystalline silicon, composed of the following components in weight percentage: 1% nucleating agent for suede surface; Defoamer 2%; Nucleation aid 0.5%; 1% surfactant; Other functional components: 1.3%; The remainder is deionized water; the total content of all the above components is 100%; the other functional components are a mixture of heavy metal chelating stabilizer, silanol passivating protectant, dispersing synergist, morphology regulator, and rhamnolipid in a mass ratio of 3:4:2.5:3:2; the velvet nucleating agent is brown algae polyphenol; the defoamer is sucrose; the auxiliary nucleating agent is tartaric acid; the surfactant is AEO-9; the heavy metal chelating stabilizer is a mixture of disodium EDTA, sodium gluconate, and phytic acid in a mass ratio of 1:1.2:2; the silanol passivating protectant is mannitol; the dispersing synergist is polyglutamic acid with a molecular weight of 10 kDa-2000 kDa, provided by Nanjing Xuankai Biotechnology Co., Ltd.; the morphology regulator is fructooligosaccharide 95 powder, provided by Shandong Bailong Chuangyuan Biotechnology Co., Ltd.

[0052] A method for preparing a texturing additive suitable for preparing homogeneous cracked textured monocrystalline silicon includes the following steps: mixing each component evenly according to the weight parts, stirring continuously at 220 r / min for 35 min; then letting it stand for 35 min, filtering it four times using a 0.2 μm aqueous filter membrane, sealing the filtrate in plastic buckets, and storing it at room temperature away from light to obtain the finished texturing additive.

[0053] A method of using the texturing additive suitable for preparing homogeneous crack textured monocrystalline silicon includes the following steps: Step S1, One-step texturing: Place the monocrystalline silicon wafer in the first alkaline texturing solution and react at 90°C for 500 seconds to form a pyramid structure on the surface of the silicon wafer. Step S2, Water washing: The silicon wafer after texturing in step S1 is washed with deionized water at 30°C for 125 seconds. Step S3, two-step texturing: The silicon wafer cleaned in step S2 is placed in the second alkaline texturing solution and reacted at 80°C for 300 seconds. Step S4, Post-processing: The silicon wafer after texturing in step S3 is washed with deionized water at 30°C for 125 seconds and then dried.

[0054] In step S1, the first alkaline texturing solution comprises the following components by weight percentage: 2% of the first-step texturing additive, 3% of the alkali, and the balance being deionized water; the alkali is sodium hydroxide; the grade of the first-step texturing additive is JUNHE®2550; In step S3, the second alkaline texturing solution comprises the following components by weight percentage: 2% of the second-step texturing additive, 2% of the alkali, and the balance being deionized water, the alkali being sodium hydroxide; the second-step texturing additive is the above-mentioned texturing additive suitable for preparing homogeneous cracked textured monocrystalline silicon; In step S4, the drying temperature is 100°C, and the drying time is 800 seconds.

[0055] Comparative Example 1 A texturing additive and its application method suitable for preparing homogeneous cracked textured monocrystalline silicon are basically the same as in Example 5, except that an equal amount of silanol passivating protectant is used instead of rhamnolipid.

[0056] Comparative Example 2 A texturing additive and its application method suitable for preparing homogeneous cracked textured monocrystalline silicon are basically the same as in Example 5, except that an equal amount of rhamnose lipolipide is used instead of the silanol passivation protectant.

[0057] Comparative Example 3 A texturing additive and its method of use suitable for preparing homogeneous cracked textured monocrystalline silicon are basically the same as those in Example 5, except that an equal amount of rhamnose glycolipid is used instead of the morphology modifier.

[0058] Comparative Example 4 A texturing additive and its method of use suitable for preparing homogeneous cracked textured monocrystalline silicon are basically the same as those in Example 5, except that an equal amount of morphology modifier is used instead of rhamnolipin.

[0059] To further illustrate the beneficial technical effects of the texturing additive applicable to the preparation of uniformly cracked textured monocrystalline silicon according to the embodiments of the present invention, relevant performance tests were conducted on the silicon wafers prepared in each example. The test results are shown in Table 1. The monocrystalline silicon wafers used for testing were M2, P-type, and... <100> The crystal orientation of the single-crystal silicon wafer is as follows: The reflectance of the front and back sides of the silicon wafer is measured using an NXT Helios-rc reflectance meter, and the average value is taken as the average reflectance; the surface morphology is observed using a scanning electron microscope (SEM), and the pyramidal specific surface area (the ratio of the actual surface area to the projected area) is calculated based on image analysis.

[0060] Table 1

[0061] As shown in Table 1, the test data indicates that Example 5 of this invention, through a specific ratio of heavy metal chelating stabilizer, silanol passivating protectant, dispersing synergist, morphology modifier, and rhamnolipid, achieves a good synergistic effect among its components. The average reflectance of the texturized monocrystalline silicon wafer is as low as 9.0%, and the pyramidal specific surface area reaches 1.35. This performance is significantly better than that of Comparative Examples 1-4, which replaced or lacked key functional components, and is also significantly superior to similar products in the prior art (which have an average reflectance of 10.2% and a pyramidal specific surface area of ​​1.24). Each comparative example, due to the disruption of the formulation system, the lack of rhamnolipid micro-homogenization regulation or silanol passivation, and the lack of morphology regularization, all exhibited problems of increased reflectance and decreased specific surface area. This confirms that the formulation can effectively optimize the textured surface morphology of silicon wafers and improve light absorption performance.

[0062] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention. The scope of protection claimed by the appended claims and their equivalents is defined.

Claims

1. A texturing additive suitable for preparing homogeneous cracked textured monocrystalline silicon, characterized in that, It consists of the following components by mass percentage: Nucleating agent for suede surface: 0.5-1%; Defoamer 0.02-2%; Nucleation aid 0.1-0.5%; Surfactant 0.1-1%; Other functional components: 0.23-1.3%; The remainder is deionized water; the total content of the above components is 100%; the other functional components are heavy metal chelating stabilizers, silanol passivating protectants, dispersing synergists, morphology regulators, and rhamnolipids compounded in a mass ratio of (0.5-3):(0.8-4):(0.4-2.5):(0.6-3):(0.3-2).

2. The texturing additive according to claim 1, suitable for preparing homogeneous cracked textured monocrystalline silicon, is characterized in that, The nucleating agent for the textured surface is one or more of brown algae polyphenols, water-soluble chitosan, sodium polyacrylate, and cyclodextrin; the water-soluble chitosan has a degree of deacetylation ≥90% and a weight-average molecular weight of 200,000; the cyclodextrin is technical grade hydroxypropyl β-cyclodextrin with a molar degree of substitution of 0.5-1; and the sodium polyacrylate has a weight-average molecular weight of 5100.

3. The texturing additive according to claim 1, suitable for preparing homogeneous cracked textured monocrystalline silicon, is characterized in that, The defoamer is one or more of sucrose and sodium alginate; the nucleating agent is one or more of tartaric acid, sodium citrate, glycerol polyether, and anthocyanin; and the glycerol polyether is glycerol polyoxyethylene ether G-18.

4. The texturing additive according to claim 1, suitable for preparing homogeneous cracked textured monocrystalline silicon, is characterized in that, The surfactant is one or more of PEG-200, PEG-400, PEG-600, fluorocarbon surfactant, and AEO-9; the grade of the fluorocarbon surfactant is FHJ-633.

5. The texturing additive according to claim 1, suitable for preparing homogeneous cracked textured monocrystalline silicon, characterized in that, The heavy metal chelating stabilizer is a compound of disodium EDTA, sodium gluconate, and phytic acid in a mass ratio of 1:(0.8-1.2):(1-2); the silanol passivation protectant is at least one of mannitol, sorbitol, and xylitol.

6. The texturing additive according to claim 1, suitable for preparing homogeneous cracked textured monocrystalline silicon, is characterized in that, The dispersing synergist is polyglutamic acid with a molecular weight of 10 kDa-2000 kDa; the morphology regulator is fructooligosaccharide 95 powder.

7. A method for preparing a texturing additive suitable for preparing homogeneous cracked textured monocrystalline silicon according to any one of claims 1-6, characterized in that, The process includes the following steps: mixing each component according to its weight proportions, stirring continuously at 200-220 r / min for 25-35 min; then letting it stand for 25-35 min, filtering it 2-4 times using a 0.2 μm aqueous filter membrane, sealing the filtrate in plastic containers, and storing it at room temperature away from light to obtain the finished fabrication additive.

8. A method of using a texturing additive according to any one of claims 1-6 for preparing homogeneous cracked textured monocrystalline silicon, characterized in that, Includes the following steps: Step S1, One-step texturing: Place the monocrystalline silicon wafer in the first alkaline texturing solution and react at 70-90℃ for 200-500 seconds to form a pyramid structure on the surface of the silicon wafer. Step S2, Water washing: The silicon wafer after texturing in step S1 is washed with deionized water at 20-30℃ for 115-125 seconds. Step S3, two-step texturing: The silicon wafer cleaned in step S2 is placed in the second alkaline texturing solution and reacted at 50-80℃ for 50-300 seconds; Step S4, Post-processing: The silicon wafer after texturing in step S3 is washed with deionized water at 20-30℃ for 115-125 seconds and then dried.

9. The method of using the texturing additive for preparing homogeneous cracked textured monocrystalline silicon according to claim 8, characterized in that, The first alkaline texturing solution in step S1 is made of the following components by weight percentage: 0.1% to 2% of the first step texturing additive, 0.5% to 3% of the alkali, and the balance being deionized water; the alkali is one or both of sodium hydroxide or potassium hydroxide; the brand of the first step texturing additive is JUNHE®2550.

10. The method of using the texturing additive for preparing homogeneous cracked textured monocrystalline silicon according to claim 8, characterized in that, In step S3, the second alkaline texturing solution comprises the following components by weight percentage: 0.1%-2% of the second-step texturing additive, 0.1%-2% of the alkali, and the balance being deionized water. The alkali is one or both of sodium hydroxide and potassium hydroxide. The second-step texturing additive is the texturing additive described above suitable for preparing monocrystalline silicon with a uniformly cracked textured surface. In step S4, the drying temperature is 80-100°C, and the drying time is 400-800 seconds.

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