CN116496444B

CN116496444B - Polyvinylpyrrolidone copolymer and preparation method and application thereof

Info

Publication number: CN116496444B
Application number: CN202310769661.XA
Authority: CN
Inventors: 王宇; 朱广东; 陈占; 郭永江
Original assignee: SHANGHAI YUKING WATER SOLUBLE MATERIAL Tech CO Ltd
Current assignee: SHANGHAI YUKING WATER SOLUBLE MATERIAL Tech CO Ltd
Priority date: 2023-06-28
Filing date: 2023-06-28
Publication date: 2023-09-22
Anticipated expiration: 2043-06-28
Also published as: CN116496444A

Abstract

The invention provides a polyvinylpyrrolidone copolymer, a preparation method and application thereof, wherein the polyvinylpyrrolidone copolymer is prepared from N-vinylpyrrolidone, hydroxyl-containing monomers, amino-containing monomers, anionic monomers and organosilane modifiers. The polyvinylpyrrolidone copolymer can be used for preparing monocrystalline silicon slice texturing additives, and the prepared monocrystalline silicon slice texturing additives have good adsorption effect on the surface of the silicon slice, and have the characteristics of short texturing time, uniform texturing, regular textured pyramid structure, adjustable textured size, simple preparation of monocrystalline silicon slice texturing liquid, small addition amount, good texturing stability and the like.

Description

Polyvinylpyrrolidone copolymer and preparation method and application thereof

Technical Field

The invention belongs to the field of monocrystalline silicon piece preparation, and particularly relates to a polyvinylpyrrolidone copolymer, a preparation method and application thereof.

Background

The surface reflectivity of the monocrystalline silicon solar cell is one of important factors influencing the photoelectric conversion efficiency of the monocrystalline silicon solar cell, the textured structure on the surface of the silicon wafer can effectively reduce the surface reflection, and wet chemical corrosion is the preparation method of the monocrystalline silicon textured structure with the lowest cost and the most extensive application. The anisotropic corrosion characteristic of the monocrystalline silicon in hot alkali liquor is generally utilized to realize that a pyramid suede structure is corroded on the surface, the reflectivity of the surface of a silicon wafer is reduced, a light trap is formed in the battery, and the strong incident light absorption efficiency and the conversion efficiency of the monocrystalline silicon solar battery are improved.

Sodium carbonate is adopted for texturing, the reaction temperature is controlled to be 80-90 ℃, alkali is consumed and silicate is continuously generated in the reaction process, a large amount of bubbles are generated, the concentration of hydroxyl ions in the reactant is reduced, the surface of a silicon wafer cannot fully contact alkali liquor, the texturing efficiency is affected, and the pyramid size is unevenly distributed, so that the ideal effect cannot be achieved in the texturing process. The reaction is generally inhibited by adding sodium silicate and isopropanol in industry, and the reaction rate is controlled, so that a better suede state is obtained.

CN105671642a discloses a solar photovoltaic cell silicon wafer texturing solution, which consists of a texturing agent and an oxidant, wherein the texturing agent comprises sodium hydroxide, sodium silicate, sodium acetate, ethanol, isopropanol, lactic acid and pure water; the texturing agent and the oxidant are packaged separately, the texturing agent is subjected to preliminary texturing treatment, and the oxidant is subjected to texturing modification; the volume ratio of the texturing agent to the oxidant is 1:1-4. The texturing solution provided by the technical scheme has good texturing effect, can uniformly, stably and finely process the solar silicon wafer, and has low damage rate to the silicon wafer. However, isopropanol has relatively low boiling point, is easy to volatilize, has strict temperature control requirement in the corrosion process, and is added continuously according to consumption in the corrosion process, so that the method is unfavorable for large-scale use, and therefore, the alcohol-free texturing additive is widely researched and applied by people.

CN110396725a discloses a texturing additive for monocrystalline silicon piece and application thereof, the texturing additive comprises the following components in percentage by weight: inorganic alkali with mass concentration of 1-2.5%; a surfactant with a mass concentration of 1-20%; chelating agent with mass concentration of 0.5% -2.5%; defoaming agent with mass concentration of 0.5-2.5% and wetting dispersant with mass concentration of 1-15%; the balance of deionized water. The wool making additive provided by the technical scheme is low in cost, friendly to human bodies and environment, harmless, capable of shortening the wool making time and improving the wool making efficiency.

CN111321471a discloses a monocrystalline silicon wool making additive with low weight and application thereof, the monocrystalline silicon wool making additive comprises the following components in percentage by weight: the monocrystalline silicon wool making additive provided by the technical scheme can effectively shorten wool making time, improve the density of a pyramid obtained by wool making, reduce the volume of the pyramid, and reduce the weight of a silicon wafer during wool making.

However, the existing alcohol-free texturing additives are mostly prepared by compounding a surfactant and organic/inorganic salts, and the problems that the surfactant is difficult to effectively adsorb on the surface of a silicon wafer, the etching rate is controlled, the texturing temperature is high and the texturing time is long still exist, meanwhile, as the use time of the texturing liquid is prolonged, the adsorption performance of the texturing additives is seriously affected due to the generation of silicate and the like, and the texturing effect is obviously reduced.

Therefore, development of a texturing additive which has good adsorption effect on the surface of a monocrystalline silicon wafer, good texturing effect, short texturing time and low cost is urgently needed.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide a polyvinylpyrrolidone copolymer, and a preparation method and application thereof. The polyvinylpyrrolidone copolymer is used for preparing the monocrystalline silicon piece texturing additive, and the prepared monocrystalline silicon piece texturing additive has the characteristics of good adsorption effect on the surface of a silicon piece, short texturing time, uniform texturing, regular textured pyramid structure, adjustable textured size, simple preparation of monocrystalline silicon piece texturing liquid, small addition amount, good texturing stability and the like.

To achieve the purpose, the invention adopts the following technical scheme:

in a first aspect, the present invention provides a polyvinylpyrrolidone copolymer, the polyvinylpyrrolidone copolymer being prepared from N-vinylpyrrolidone, a hydroxyl-containing monomer, an amino-containing monomer, an anionic monomer and an organosilane modifier.

In the invention, silicon atoms of different crystal faces of monocrystalline silicon have different energies, and the alkaline etching process has anisotropic characteristic. The etching rate of the monocrystalline silicon piece texturing additive is regulated and controlled on the surface of the monocrystalline silicon piece through adsorption, the degree of the texturing anisotropy is changed, and the monocrystalline silicon piece texturing additive is the most important factor affecting whether a good gold sub-tower textured structure can be obtained in the monocrystalline silicon piece texturing process. The invention prepares the polyvinylpyrrolidone copolymer with various group structural characteristics through N-vinyl pyrrolidone, hydroxyl-containing monomers, amino-containing monomers, anionic monomers and organosilane modifiers. In the polyvinylpyrrolidone copolymer, lactam groups introduced by N-vinylpyrrolidone can have good nonselective adsorption on the surface of a monocrystalline silicon piece, so that the polyvinylpyrrolidone copolymer can uniformly adsorb all crystal faces of the monocrystalline silicon; the amino-containing monomer is introduced with tertiary amine groups, and the adsorption of the polyvinylpyrrolidone copolymer on the surface of the alkaline monocrystalline silicon piece can be enhanced under alkaline environment by the weak cation characteristic of the tertiary amine groups; the silicon oxygen base and the silicon hydrogen base introduced by the organosilane modifier have excellent structural similarity with the silicon surface, so that the polyvinylpyrrolidone copolymer and the wetting adsorption characteristics of monocrystalline silicon wafer texturing liquid comprising the polyvinylpyrrolidone copolymer and the monocrystalline silicon wafer surface are greatly improved, and the long-term stable adsorption and defoaming capability of the polyvinylpyrrolidone copolymer on the monocrystalline silicon wafer surface is greatly improved; the hydroxyl introduced by the hydroxyl-containing monomer and the anionic group introduced by the anionic monomer provide good alkali resistance for the polyvinylpyrrolidone copolymer, so that the polyvinylpyrrolidone copolymer can stably exist under a high-temperature strong base system, hydroxide ion exchange is provided, and corrosion texturing is continuously carried out on the surface of the monocrystalline silicon piece.

Preferably, the hydroxyl-containing monomer comprises an alkyl enol.

Preferably, the alkyl enols comprise any one or a combination of at least two of 2-methyl-2-propen-1-ol, 3-buten-1-ol, cis-2-penten-1-ol, 4-penten-1-ol, 3-methyl-2-buten-1-ol, 1-penten-3-ol or ethylene glycol monovinyl ether.

Preferably, the amino group-containing monomer comprises a tertiary amine type acrylamide monomer.

Preferably, the tertiary amine acrylamide monomer comprises any one or a combination of at least two of N, N-dimethylacrylamide, 4-acryloylmorpholine or dimethylaminopropyl acrylamide.

Preferably, the anionic monomer comprises a vinyl-containing monomer capable of ionizing anions in aqueous solution.

Preferably, the anionic monomer comprises any one or a combination of at least two of acrylic acid, methacrylic acid, p-styrenesulfonic acid, methyl-p-styrenesulfonic acid, 2-methyl-2-acrylamido-1-propanesulfonic acid, itaconic anhydride, maleic acid or maleic anhydride.

Preferably, the organosilane modifier comprises any one or a combination of at least two of a monohalogen silane monomer, a monohydroxy silane monomer or a monoalkoxysilane monomer.

Preferably, the organosilane modifier comprises any one or a combination of at least two of trimethylchlorosilane, trimethylbromosilane, triethylchlorosilane, triphenylchlorosilane, dimethylmonohydrosilane, phenyldimethylchlorosilane, diphenylmethylchlorosilane, trimethylmonohydroxysilane, triethylmonohydroxysilane, triphenylmonohydroxysilane, trimethylmonomethoxysilane or trimethylethoxysilane.

Preferably, the mass ratio of the N-vinyl pyrrolidone to the hydroxyl-containing monomer to the amino-containing monomer to the anionic monomer is 100:10-20:15-30:5-15. For example, the hydroxyl group-containing monomer may be 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 17 parts, 18 parts, 19 parts, 20 parts, or the like, the amino group-containing monomer may be 15 parts, 16 parts, 18 parts, 20 parts, 21 parts, 23 parts, 25 parts, 26 parts, 27 parts, 29 parts, or 30 parts, or the like, and the anionic monomer may be 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, or 15 parts, or the like, based on 100 parts by mass of the N-vinylpyrrolidone.

In the invention, hydroxyl-containing monomers and anionic monomers in the raw materials for preparing the polyvinylpyrrolidone copolymer introduce hydroxyl and anionic groups into the polyvinylpyrrolidone copolymer, so that the alkali resistance and hydroxyl ion exchange effect are provided, if the mass parts of the hydroxyl-containing monomers and the anionic monomers are too small, the alkali resistance of the prepared polyvinylpyrrolidone copolymer is reduced, the high tolerance in a strong alkali environment cannot be met, and the texturing rate is reduced; if the mass fraction is too large, the prepared polyvinylpyrrolidone copolymer has too high hydroxide ion exchange rate, and the texturing effect is reduced. The addition of the amino-containing monomer enables the polyvinylpyrrolidone copolymer to obtain a certain cationic characteristic, can effectively assist in increasing the adsorption effect of the polyvinylpyrrolidone copolymer on the surface of the monocrystalline silicon wafer in a strong alkaline environment, has the advantages of unobvious adsorption effect when the mass fraction is too small, and is difficult to elute from the surface of the monocrystalline silicon wafer and remain on the surface of the monocrystalline silicon wafer when the mass fraction is too large, so that the performance of the monocrystalline silicon solar cell panel is affected.

Preferably, the mass of the organosilane modifying agent is 30-80%, for example 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75% or 80% of the mass of the hydroxyl-containing monomer.

In the invention, the organosilane modifier is grafted on the polyvinylpyrrolidone copolymer through hydroxyl coupling, so that the wetting and adsorption characteristics of the polyvinylpyrrolidone copolymer on the surface of the monocrystalline silicon piece are effectively improved. If the mass fraction of the polyvinyl pyrrolidone is too small, the improvement on the polyvinyl pyrrolidone copolymer is not obvious, and the wettability of the polyvinyl pyrrolidone copolymer on the monocrystalline silicon piece is difficult to be obviously improved; when the mass fraction is too large, the hydrophobicity of the polyvinylpyrrolidone copolymer is increased, which is unfavorable for maintaining the stability under the high-temperature strong alkali environment.

Preferably, the raw materials for preparing the polyvinylpyrrolidone copolymer further comprise an initiator.

Preferably, the initiator comprises an organic peroxide initiator.

Preferably, the organic peroxide initiator comprises any one or a combination of at least two of di-tert-amyl peroxide, di-tert-butyl peroxide, dicumyl peroxide, dibenzoyl peroxide, tert-butyl peroxybenzoate, tert-butyl peroxyethylhexanoate or tert-butyl peroxyacetate.

Preferably, the mass of the initiator is 0.5-10%, such as 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10% of the total mass of the N-vinylpyrrolidone, hydroxyl group-containing monomer, amino group-containing monomer and anionic monomer, etc.

In a second aspect, the present invention provides a process for the preparation of a polyvinylpyrrolidone copolymer as described in the first aspect, the process comprising the steps of: mixing N-vinyl pyrrolidone, hydroxyl-containing monomer, amino-containing monomer and anion monomer, reacting at a constant temperature, and adding organosilane modifier for modification to obtain the polyvinylpyrrolidone copolymer.

Preferably, the mixing further comprises mixing the solvent and the initiator with the N-vinyl pyrrolidone, the hydroxyl-containing monomer, the amino-containing monomer, and the anionic monomer.

Preferably, the solvent comprises a hydrophilic polar solvent.

Preferably, the solvent comprises any one or a combination of at least two of ethylene glycol methyl ether, ethylene glycol butyl ether, propylene glycol butyl ether, diethylene glycol methyl ether, diethylene glycol dimethyl ether, dipropylene glycol methyl ether, N-methylpyrrolidone, N-dimethylformamide or dimethyl sulfoxide.

Preferably, the step of mixing comprises adding a mixture of N-vinylpyrrolidone, hydroxyl-containing monomer, amino-containing monomer, anionic monomer and initiator to a solvent of 90-160 ℃ (e.g., 90 ℃,100 ℃, 110 ℃, 120 ℃, 130 ℃, 140 ℃,150 ℃ or 160 ℃ etc.) at once.

Preferably, the step of mixing comprises adding the mixed solution of N-vinylpyrrolidone, hydroxyl group-containing monomer, amino group-containing monomer, anionic monomer and initiator to the solvent of 90 to 160 ℃ (e.g., 90 ℃,100 ℃, 110 ℃, 120 ℃, 130 ℃, 140 ℃,150 ℃, 160 ℃, etc.) in equal portions in stages of 2 to 10 (e.g., 2, 3, 4, 5, 6, 7, 8, 9, 10, etc.) times, each time at intervals of 30 to 60 minutes, e.g., 35 minutes, 40 minutes, 45 minutes, 50 minutes, 55 minutes, 60 minutes, etc.

Preferably, the step of mixing comprises dropwise adding a mixture of N-vinylpyrrolidone, hydroxyl group-containing monomer, amino group-containing monomer, anionic monomer and initiator to a solvent of 90-160 ℃ (e.g., 90 ℃,100 ℃, 110 ℃, 120 ℃, 130 ℃, 140 ℃,150 ℃ or 160 ℃ etc.) for a period of 2-5 h, e.g., 2h, 2.5 h, 3h, 3.5h, 4 h, 4.5 h or 5h, etc.

Preferably, the sum of the mass percentages of the N-vinylpyrrolidone, hydroxyl group-containing monomer, amino group-containing monomer and anionic monomer is 40 to 60%, such as 40%, 42%, 44%, 46%, 48%, 50%, 52%, 54%, 56%, 58% or 60%, etc., based on 100% of the mass of the N-vinylpyrrolidone, hydroxyl group-containing monomer, amino group-containing monomer, anionic monomer and solvent.

Preferably, the reaction is carried out under nitrogen.

Preferably, the temperature of the reaction is 90-160 ℃ (e.g., 90 ℃,100 ℃, 110 ℃, 120 ℃, 130 ℃, 140 ℃,150 ℃ or 160 ℃, etc.), and the reaction time is 1-3 h. (e.g., 1 h, 1.2 h, 1.5 h, 1.8 h, 2h, 2.4 h, 2.5 h, 2.6 h, 2.8 h, or 3h, etc.).

Preferably, the modification is at a temperature of 40-70 ℃ (e.g., 40 ℃, 45 ℃, 48 ℃, 50 ℃, 55 ℃, 60 ℃, 65 ℃, 68 ℃, or 70 ℃, etc.), and the modification is for a time of 1-5 h (e.g., 1 h, 1.5 h, 2h, 2.5 h, 3h, 3.5h, 4 h, 4.5 h, 4.8 h, or 5h, etc.).

Preferably, the modification further comprises a step of neutralization, wherein the neutralization is performed by adding an alkaline substance.

Preferably, the alkaline substance comprises an organic base and/or an inorganic base.

Preferably, the alkaline substance comprises any one or a combination of at least two of ethanolamine, triethanolamine, ammonia water, sodium hydroxide or strong potassium oxide.

In a third aspect, the present invention provides a monocrystalline silicon wafer texturing additive comprising a polyvinylpyrrolidone copolymer as described in the first aspect.

Preferably, the monocrystalline silicon piece texturing additive comprises the following components in percentage by mass: the polyvinylpyrrolidone copolymer of the first aspect is 0.1-2% (e.g., 0.1%, 0.3%, 0.5%, 0.7%, 1%, 1.2%, 1.5%, 1.8%, or 2%, etc.) and deionized water 98-99.9% (e.g., 98%, 98.2%, 98.4%, 98.6%, 98.8%, 99%, 99.4%, 99.6%, or 99.9%, etc.).

In a fourth aspect, the invention provides a monocrystalline silicon piece texturing solution, which comprises the polyvinylpyrrolidone copolymer according to the first aspect or the monocrystalline silicon piece texturing additive according to the third aspect.

Preferably, the monocrystalline silicon piece texturing solution comprises the following components in percentage by mass: the monocrystalline silicon piece texturing additive according to the third aspect, 0.1-1.5% (e.g. 0.1%, 0.2%, 0.4%, 0.6%, 0.8%, 0.10%, 0.12%, 0.14% or 0.15%, etc.) and 98.5-99.9% (e.g. 98.5%, 98.7%, 98.9%, 99.0%, 99.2%, 99.4%, 99.6%, 99.8% or 99.9%, etc.) of an inorganic alkali solution.

Preferably, the inorganic alkaline solution is a sodium hydroxide solution having a mass percent of 0.5-1% (e.g., 0.5%, 0.55%, 0.6%, 0.65%, 0.7%, 0.75%, 0.8%, 0.85%, 0.9%, 0.95%, 1%, etc.) of sodium hydroxide.

In a fifth aspect, the present invention provides the use of a polyvinylpyrrolidone copolymer as described in the first aspect for the texturing of monocrystalline silicon wafers.

Preferably, the application comprises the steps of:

(1) Mixing the polyvinylpyrrolidone copolymer of the first aspect with deionized water to obtain the monocrystalline silicon piece texturing additive.

(2) Mixing the monocrystalline silicon piece texturing additive prepared in the step (1) with sodium hydroxide alkali solution to obtain monocrystalline silicon piece texturing solution.

(3) Immersing the monocrystalline silicon piece into the monocrystalline silicon piece texturing solution in the step (2) for texturing, wherein the temperature is 75-95 ℃ (such as 75 ℃, 77 ℃, 79 ℃, 80 ℃, 82 ℃, 84 ℃, 86 ℃, 88 ℃, 90 ℃, 92 ℃ or 95 ℃ and the like) and the time is 4-8 min (such as 4min, 4.5 min, 5 min, 5.5 min, 6min, 6.5 min, 7 min, 7.5 min or 8min and the like), so as to obtain the textured monocrystalline silicon piece.

Compared with the prior art, the invention has the following beneficial effects:

the invention prepares the polyvinylpyrrolidone copolymer with various group structural characteristics through N-vinyl pyrrolidone, hydroxyl-containing monomers, amino-containing monomers, anionic monomers and organosilane modifiers. The polyvinylpyrrolidone copolymer effectively solves the problems that the prior monocrystalline silicon wafer texture-making additive has poor adsorption on the surface of a silicon wafer and is difficult to effectively regulate the corrosion rate of the surface of the silicon wafer, and the monocrystalline silicon wafer texture-making additive prepared by the polyvinylpyrrolidone copolymer has the characteristics of uniform texture, regular texture pyramid structure, short texture-making time, adjustable texture size, simple texture-making liquid preparation, less polyvinylpyrrolidone copolymer addition, good texture-making stability and the like, can obviously reduce the reflectivity of the monocrystalline silicon wafer, and improves the light absorption conversion rate of the monocrystalline silicon wafer.

Drawings

Fig. 1 is an SEM electron microscope image of a textured monocrystalline silicon piece provided in example 1.

Detailed Description

The technical scheme of the invention is further described by the following specific embodiments. It will be apparent to those skilled in the art that the examples are merely to aid in understanding the invention and are not to be construed as a specific limitation thereof.

Example 1

The embodiment provides a polyvinylpyrrolidone copolymer, a preparation method and application thereof, wherein the mass ratio of N-vinylpyrrolidone, hydroxyl-containing monomer (2-methyl-2-propylene-1-ol), amino-containing monomer (N, N-dimethylacrylamide) and anionic monomer (acrylic acid) in the preparation raw materials of the polyvinylpyrrolidone copolymer is 100:10:15:10; the mass of the organosilane modifier (trimethylchlorosilane) is 50% of the mass of the hydroxyl-containing monomer.

The preparation method comprises the following steps:

under the nitrogen environment, 150 g ethylene glycol methyl ether is added into a flask, heated to 160 ℃, dropwise added with a mixed solution consisting of 100g of N-vinyl pyrrolidone, 10g of 2-methyl-2-propylene-1-alcohol, 15g of N, N-dimethyl acrylamide, 10g acrylic acid, 13.5 g di-tert-butyl peroxide and 53 g ethylene glycol methyl ether, the dropwise added time is 2h, the dropwise added time is 1 h after the completion of dropwise adding, the temperature is reduced to 70 ℃, 5g trimethylchlorosilane is added, stirring modification treatment is 1 h, and 6g sodium hydroxide and 28 g water are added for neutralization treatment, thus obtaining the polyvinylpyrrolidone copolymer.

The application of the polyvinylpyrrolidone copolymer in the texturing of monocrystalline silicon wafers comprises the following steps:

(1) And mixing the polyvinylpyrrolidone copolymer with deionized water, wherein the mass percentage of the polyvinylpyrrolidone copolymer is 1% based on 100% of the total mass of the polyvinylpyrrolidone copolymer and the deionized water, and thus the monocrystalline silicon wafer texturing additive is obtained.

(2) Mixing the monocrystalline silicon piece texturing additive and a sodium hydroxide solution (the mass percentage of sodium hydroxide is 0.5%), wherein the mass percentage of the monocrystalline silicon piece texturing additive is 0.5% based on 100% of the total mass of the monocrystalline silicon piece texturing additive and the sodium hydroxide solution, and obtaining monocrystalline silicon piece texturing liquid.

(3) Immersing the monocrystalline silicon piece into the monocrystalline silicon piece texturing solution in the step (2), texturing for 5 min at 85 ℃ to obtain the textured monocrystalline silicon piece, and continuously texturing for 12 hours.

Example 2

The embodiment provides a polyvinylpyrrolidone copolymer, a preparation method and application thereof, wherein the mass ratio of N-vinylpyrrolidone, hydroxyl-containing monomer (3-methyl-2-butene-1-ol), amino-containing monomer (N, N-dimethyl methacrylamide) and anionic monomer (methacrylic acid) in the preparation raw materials of the polyvinylpyrrolidone copolymer is 100:20:25:5; the mass of the organosilane modifier (triethylmonohydroxy silane) was 30% of the mass of the hydroxyl group-containing monomer.

The preparation method comprises the following steps:

under nitrogen environment, adding 100g diethylene glycol methyl ether into a flask, heating to 140 ℃, dropwise adding a mixed solution consisting of 100g of N-vinyl pyrrolidone, 20g of 3-methyl-2-butene-1-ol, 25g of N, N-dimethyl methacrylamide, 5g methacrylic acid, 4.5g di-tert-amyl peroxide and 50 g diethylene glycol methyl ether, dropwise adding for 4 h, carrying out heat preservation reaction 2h after dropwise adding, cooling to 40 ℃, adding 6g triethyl monohydroxy silane, stirring and modifying 5h, adding 4.0 g ethanolamine and 24 g water, and carrying out neutralization treatment to obtain the polyvinylpyrrolidone copolymer.

(1) And mixing the polyvinylpyrrolidone copolymer with deionized water, wherein the mass percentage of the polyvinylpyrrolidone copolymer is 1.5% based on 100% of the total mass of the polyvinylpyrrolidone copolymer and the deionized water, and thus the monocrystalline silicon slice texturing additive is obtained.

(2) Mixing the monocrystalline silicon piece texturing additive with a sodium hydroxide solution (the mass percentage of sodium hydroxide is 0.7%), wherein the mass percentage of the monocrystalline silicon piece texturing additive is 1% based on 100% of the total mass of the monocrystalline silicon piece texturing additive and the sodium hydroxide solution, and obtaining monocrystalline silicon piece texturing liquid.

(3) Immersing the monocrystalline silicon piece into the monocrystalline silicon piece texturing solution in the step (2), texturing for 8min at 75 ℃ to obtain the textured monocrystalline silicon piece, and continuously texturing for 12 hours.

Example 3

The embodiment provides a polyvinylpyrrolidone copolymer, a preparation method and application thereof, wherein the mass ratio of N-vinylpyrrolidone, hydroxyl-containing monomer (2-butene-1-ol), amino-containing monomer (4-acryloylmorpholine) and anionic monomer (p-styrenesulfonic acid) in the preparation raw materials of the polyvinylpyrrolidone copolymer is 100:15:30:15; the mass of the organosilane modifier (trimethylethoxysilane) was 80% of the mass of the hydroxyl group-containing monomer.

The preparation method comprises the following steps:

under the nitrogen environment, 107g N-methyl pyrrolidone is added into a flask, the flask is heated to 110 ℃, mixed liquid consisting of 100g N-vinyl pyrrolidone, 15g 2-butene-1-ol, 30g 4-acryloylmorpholine, 15g p-styrenesulfonic acid and 8g tert-butyl peroxyethylhexanoate is dripped for 5 hours, the reaction is carried out for 2 hours after the dripping is finished, the temperature is reduced to 50 ℃, 12g trimethyl-ethoxysilane is added, stirring modification treatment is carried out for 2 hours, 5g potassium hydroxide and 11g water are added for neutralization treatment, and the polyvinylpyrrolidone copolymer is obtained.

(1) And mixing the polyvinylpyrrolidone copolymer with deionized water, wherein the mass percentage of the polyvinylpyrrolidone copolymer is 0.1% based on 100% of the total mass of the polyvinylpyrrolidone copolymer and the deionized water, and thus the monocrystalline silicon slice texturing additive is obtained.

(2) Mixing the monocrystalline silicon piece texturing additive with a sodium hydroxide solution (the mass percentage of sodium hydroxide is 1%), wherein the mass percentage of the monocrystalline silicon piece texturing additive is 1.5% based on the total mass of the monocrystalline silicon piece texturing additive and the sodium hydroxide solution being 100%, and obtaining monocrystalline silicon piece texturing liquid.

(3) Immersing the monocrystalline silicon piece into the monocrystalline silicon piece texturing solution in the step (2), texturing for 4min at 95 ℃ to obtain the textured monocrystalline silicon piece, and continuously texturing for 12 hours.

Example 4

The embodiment provides a polyvinylpyrrolidone copolymer, a preparation method and application thereof, wherein the mass ratio of N-vinylpyrrolidone to hydroxyl-containing monomer (ethylene glycol monovinyl ether), amino-containing monomer (dimethylaminopropyl acrylamide) to anionic monomer (2-methyl-2-acrylamide-1-propane sulfonic acid) in the preparation raw materials of the polyvinylpyrrolidone copolymer is 100:15:30:15; the mass of the organosilane modifier (trimethylchlorosilane) is 30% of the mass of the hydroxyl-containing monomer.

The preparation method comprises the following steps:

under the nitrogen environment, 100g of ethylene glycol butyl ether is added into a flask, heated to 90 ℃, dropwise added with a mixed monomer solution consisting of 100g N-vinyl pyrrolidone, 15g of ethylene glycol monovinyl ether, 20g of dimethylaminopropyl acrylamide, 10g of 2-methyl-2-acrylamide-1-propane sulfonic acid, 11.6g of dibenzoyl peroxide and 45g of ethylene glycol butyl ether, dropwise added for 3.5 hours, reacted for 3 hours after dropwise adding, cooled to 60 ℃, added with 4.5g of trimethylchlorosilane, stirred and modified for 2 hours, added with 3g of ethanolamine and 7.5g of water for neutralization treatment, and thus the polyvinylpyrrolidone copolymer is obtained.

(1) And mixing the polyvinylpyrrolidone copolymer with deionized water, wherein the mass percentage of the polyvinylpyrrolidone copolymer is 2% based on 100% of the total mass of the polyvinylpyrrolidone copolymer and the deionized water, and thus the monocrystalline silicon wafer texturing additive is obtained.

(2) Mixing the monocrystalline silicon piece texturing additive with a sodium hydroxide solution (the mass percentage of sodium hydroxide is 0.8%), wherein the mass percentage of the monocrystalline silicon piece texturing additive is 0.1% based on 100% of the total mass of the monocrystalline silicon piece texturing additive and the sodium hydroxide solution, and obtaining monocrystalline silicon piece texturing liquid.

(3) Immersing the monocrystalline silicon piece into the monocrystalline silicon piece texturing solution in the step (2), texturing for 6min at 80 ℃ to obtain the textured monocrystalline silicon piece, and continuously texturing for 12 hours.

Example 5

The present example provides a polyvinylpyrrolidone copolymer, a preparation method and an application thereof, which differ from example 1 only in that the organosilane modifier is phenyl dimethyl chlorosilane, and the mass of the organosilane modifier is 25% of the mass of the hydroxyl-containing monomer; in the preparation method, the mass of phenyl dimethyl chlorosilane is 2.5g, and other raw materials, the dosage and the preparation method are the same as those of the example 1.

Example 6

The embodiment provides a polyvinylpyrrolidone copolymer, a preparation method and application thereof, which are different from embodiment 1 only in that the organosilane modifier is triethylchlorosilane, and the mass of the organosilane modifier is 90% of the mass of the hydroxyl-containing monomer; in the preparation method, the mass of triethylchlorosilane is 9g, and other raw materials, the dosage and the preparation method are the same as those of the example 1.

Example 7

The embodiment provides a polyvinylpyrrolidone copolymer, a preparation method and an application thereof, which are different from embodiment 1 only in that the hydroxyl-containing monomer is cis-2-pentene-1-ol, and the mass ratio of the N-vinyl pyrrolidone to the hydroxyl-containing monomer to the amino-containing monomer to the anionic monomer is 100:6:15:10; in the preparation method, the mass of cis-2-pentene-1-ol is 6g, and other raw materials, the dosage and the preparation method are the same as those of the example 1.

Example 8

The embodiment provides a polyvinylpyrrolidone copolymer, a preparation method and an application thereof, which are different from embodiment 1 only in that the hydroxyl-containing monomer is 3-methyl-2-butene-1-ol, and the mass ratio of the N-vinyl pyrrolidone to the hydroxyl-containing monomer to the amino-containing monomer to the anionic monomer is 100:25:15:10; in the preparation method, the mass of 3-methyl-2-buten-1-ol is 25g, and other raw materials, the using amount and the preparation method are the same as those of the example 1.

Example 9

The embodiment provides a polyvinylpyrrolidone copolymer, a preparation method and an application thereof, which are different from embodiment 1 only in that the amino-containing monomer is N, N-dimethylacrylamide, and the mass ratio of the N-vinylpyrrolidone to the hydroxyl-containing monomer to the amino-containing monomer to the anionic monomer is 100:10:10:10; in the preparation method, the mass of the N, N-dimethylacrylamide is 10g, and other raw materials, the using amount and the preparation method are the same as those of the example 1.

Example 10

The embodiment provides a polyvinylpyrrolidone copolymer, a preparation method and an application thereof, which are different from embodiment 1 only in that the amino-containing monomer is N, N-dimethylacrylamide, and the mass ratio of the N-vinylpyrrolidone to the hydroxyl-containing monomer to the amino-containing monomer to the anionic monomer is 100:10:35:10; in the preparation method, the mass of the N, N-dimethylacrylamide is 35 g, and other raw materials, the using amount and the preparation method are the same as those of the example 1.

Example 11

The embodiment provides a polyvinylpyrrolidone copolymer, a preparation method and an application thereof, which are different from embodiment 1 only in that the anionic monomer is itaconic acid, and the mass ratio of the N-vinyl pyrrolidone to the hydroxyl-containing monomer to the amino-containing monomer to the anionic monomer is 100:10:15:2; in the preparation method, the mass of itaconic acid is 2g, and other raw materials, the dosage and the preparation method are the same as those of the example 1.

Example 12

The embodiment provides a polyvinylpyrrolidone copolymer, a preparation method and an application thereof, which are different from embodiment 1 only in that the anionic monomer is maleic anhydride, and the mass ratio of the N-vinyl pyrrolidone, the hydroxyl-containing monomer, the amino-containing monomer and the anionic monomer is 100:10:15:20; in the preparation method, the mass of the maleic anhydride is 20g, and other raw materials, the using amount and the preparation method are the same as those of the example 1.

Comparative example 1

The comparative example provides a texturing additive and application thereof, wherein the texturing additive is a commercial texturing additive Phara-06.

The application comprises the following steps:

(1) Mixing the texturing additive Phara-06 with deionized water, wherein the mass percentage of the texturing additive Phara-06 is 2%, and obtaining the monocrystalline silicon slice texturing additive.

(2) Mixing the monocrystalline silicon piece texturing additive with a sodium hydroxide solution (the mass percentage of sodium hydroxide is 1%), wherein the mass percentage of the monocrystalline silicon piece texturing additive is 1.5%, and obtaining monocrystalline silicon piece texturing liquid.

(3) Immersing the monocrystalline silicon piece into the monocrystalline silicon piece texturing solution in the step (2), texturing for 8min at 80 ℃ to obtain the textured monocrystalline silicon piece, and continuously texturing for 12 hours.

Comparative example 2

This comparative example provides a polyvinylpyrrolidone copolymer and a preparation method and application thereof, which are different from example 1 only in that no organosilane modifier (trimethylchlorosilane) is added, and other raw materials, amounts and preparation methods are the same as those of example 1.

Comparative example 3

This comparative example provides a polyvinylpyrrolidone copolymer and a preparation method and application thereof, which are different from example 1 only in that no amino group-containing monomer (N, N-dimethylacrylamide) is added, and other raw materials, amounts and preparation methods are the same as in example 1.

Comparative example 4

This comparative example provides a polyvinylpyrrolidone copolymer, a preparation method and application thereof, which are different from example 1 only in that no anionic monomer (acrylic acid) is added, and other raw materials, amounts and preparation methods are the same as in example 1.

Performance testing

The silicon loss amount of the silicon wafers after texturing prepared in examples and comparative examples was measured for reflectivity and corrosion, respectively. Monocrystalline silicon slice texturing is carried out in a way of vertically entering the monocrystalline silicon slice, the lower part of the monocrystalline silicon slice close to the bottom of the groove, and the other end of the monocrystalline silicon slice is the upper part. After the initial stage and continuous texturing operation 12 h, the reflectivities of the upper part and the lower part of the prepared monocrystalline silicon piece at the position 4 cm away from the edge of the monocrystalline silicon piece are respectively tested, and the average reflectivities of the front surface and the back surface of the monocrystalline silicon piece in the upper part and the lower part of the monocrystalline silicon piece are respectively calculated to obtain the average reflectivities of the upper part of the monocrystalline silicon piece and the lower part of the monocrystalline silicon piece, wherein the reflectivities are measured by an ultraviolet-visible spectrophotometer.

Silicon loss amount: and calculating the silicon loss by measuring the quality change of the monocrystalline silicon wafer before and after texturing.

In addition, sodium hydroxide solution (the mass percentage of sodium hydroxide is 0.5%) is adopted as monocrystalline silicon wafer texturing solution, so that the prepared silicon wafer is used as a blank comparison sample.

The test results are shown in Table 1.

TABLE 1

In Table 1 "-" represents that the result was not measured.

As can be seen from the results in Table 1, when the polyvinylpyrrolidone copolymer provided by the invention is applied to the texturing of monocrystalline silicon wafers, the prepared monocrystalline silicon wafers after the texturing have similar reflectivities at different positions, have good reflectivity uniformity, can achieve the obvious effect of reducing the reflectivity under the condition of less additive amount, and show that the polyvinylpyrrolidone copolymer provided by the invention has good controllability on the texturing process, can effectively control the texturing generation process and structure, and has important significance for reducing the thickness of the silicon wafers or the texturing of ultrathin silicon wafers. Fig. 1 is an SEM image of a monocrystalline silicon wafer after texturing, which is obtained when the polyvinylpyrrolidone copolymer provided in example 1 is applied to monocrystalline silicon wafer texturing, and fig. 1 shows that texturing is uniform and the textured pyramid structure is regular.

Examples 1 to 4, the average reflectance of the upper and lower portions of the monocrystalline silicon piece after texturing obtained in the initial stage were each in the range of 9.33% to 10.02%, and the silicon loss amount was 187 to 228 mg/dm ³ The method comprises the steps of carrying out a first treatment on the surface of the After the continuous texturing operation of 12 h, the average reflectivity of the upper part and the average reflectivity of the lower part are both in the range of 9.38-10.01%, and the silicon loss is 193-231 mg/dm ³ The stable wool making effect is still maintainedAnd the fruit is good in wool making stability. Examples 5 to 10 and example 12, the average reflectance of the upper and lower portions of the textured monocrystalline silicon wafer obtained in the initial stage were in the range of 10.56% to 12.57%, and the silicon loss amount was 225 to 350 mg/dm ³ The method comprises the steps of carrying out a first treatment on the surface of the After the continuous texturing operation of 12 h, the average reflectivity of the upper part and the lower part is in the range of 10.63-12.63%, and the silicon loss is 232-378 mg/dm ³ The average reflectivity and the amount of silicon loss increase.

When the addition amount of the organosilane modifying agent was decreased (example 5) or the addition amount of the organosilane modifying agent was increased (example 6) as compared with example 1, the average reflectance of the upper portion, the average reflectance of the lower portion and the silicon loss amount of the single crystal silicon wafer were all increased, and it was confirmed that the performance was better by using the organosilane modifying agent in a specific addition amount range.

When the amount of the hydroxyl group-containing monomer added was decreased (example 7) or the amount of the hydroxyl group-containing monomer added was increased (example 8) as compared with example 1, the average reflectance of the upper portion, the average reflectance of the lower portion and the silicon loss amount of the single crystal silicon wafer were all increased, and it was confirmed that the performance was better by using the hydroxyl group-containing monomer in the specific addition amount range.

When the amount of the amino group-containing monomer added was decreased (example 9) or the amount of the amino group-containing monomer added was increased (example 10) as compared with example 1, the average reflectance of the upper portion, the average reflectance of the lower portion and the silicon loss amount of the single crystal silicon wafer were all increased, and it was confirmed that the performance was better by using the amino group-containing monomer in the specific addition amount range.

The amount of anionic monomer added was reduced (example 11) as compared with example 1, and the alkali resistance of the resulting polyvinylpyrrolidone copolymer was reduced, and the resulting monocrystalline silicon wafer texturing solution was in a cloudy state; the addition amount of the anionic monomer was increased (example 12), and the average reflectance of the upper portion, the average reflectance of the lower portion and the silicon loss amount of the single crystal silicon wafer were all increased, demonstrating that the performance was better by using the anionic monomer in the specific addition amount range.

Compared with example 1, if no organosilane modifier was added (comparative example 2), the average reflectance increased both at the initial stage and after the continuous texturing operation of 12 h, and the silicon loss increased, because the wetting and adsorptivity of the prepared polyvinylpyrrolidone copolymer with a silicon single crystal wafer were poor, the silicon single crystal wafer was much weight-reduced, and the textured structure and reflectance were difficult to obtain effective control.

Compared with example 1, when no amino group-containing monomer was added (comparative example 3), the average reflectance increased at the initial stage and after the continuous texturing operation of 12 h, and the silicon loss amount increased, because the adsorption of the obtained polyvinylpyrrolidone copolymer on the silicon wafer surface became poor, the obtained textured surface uniformity became poor, and the reflectance was high.

Compared with example 1, if no anionic monomer is added (comparative example 4), the prepared polyvinylpyrrolidone copolymer has poor alkali resistance, and the prepared monocrystalline silicon wafer texturing solution is in a turbid state, so that the use requirement under the high-temperature strong alkali environment is difficult to meet.

The applicant states that the present invention is illustrated by the above examples as well as the preparation method and application thereof, but the present invention is not limited to the above examples, i.e. it is not meant that the present invention must be practiced in dependence upon the above examples. It should be apparent to those skilled in the art that any modification of the present invention, equivalent substitution of raw materials for the product of the present invention, addition of auxiliary components, selection of specific modes, etc., falls within the scope of the present invention and the scope of disclosure.

Claims

1. The polyvinylpyrrolidone copolymer is characterized in that the preparation raw materials of the polyvinylpyrrolidone copolymer comprise N-vinylpyrrolidone, hydroxyl-containing monomers, amino-containing monomers, anionic monomers and organosilane modifiers;

the polyvinylpyrrolidone copolymer is prepared by the following method: mixing N-vinyl pyrrolidone, hydroxyl-containing monomers, amino-containing monomers and anionic monomers, reacting, and adding an organosilane modifier for modification to obtain the polyvinylpyrrolidone copolymer;

the hydroxyl-containing monomers include alkyl enols;

the amino group-containing monomers include tertiary amine type acrylamide monomers;

the anionic monomers include vinyl-containing monomers capable of ionizing anions in aqueous solution;

the mass ratio of the N-vinyl pyrrolidone to the hydroxyl-containing monomer to the amino-containing monomer to the anionic monomer is 100:10-20:15-30:5-15;

the mass of the organosilane modifier is 30-80% of that of the hydroxyl-containing monomer;

the organosilane modifier comprises any one or a combination of at least two of a single halogen silane monomer, a single hydroxyl silane monomer or a single alkoxy silane monomer.

2. The polyvinylpyrrolidone copolymer of claim 1, wherein the alkyl enol comprises any one or a combination of at least two of 2-methyl-2-propen-1-ol, 3-buten-1-ol, cis-2-penten-1-ol, 4-penten-1-ol, 3-methyl-2-buten-1-ol or 1-penten-3-ol.

3. The polyvinylpyrrolidone copolymer of claim 1, wherein the tertiary amine acrylamide monomer comprises any one or a combination of at least two of N, N-dimethylacrylamide, N-dimethylmethacrylamide, 4-acryloylmorpholine or dimethylaminopropyl acrylamide;

the anionic monomer comprises any one or a combination of at least two of acrylic acid, methacrylic acid, p-styrene sulfonic acid, methyl p-styrene sulfonic acid, 2-methyl-2-acrylamide-1-propane sulfonic acid, itaconic anhydride, maleic acid or maleic anhydride.

4. The polyvinylpyrrolidone copolymer of claim 1, wherein the monohalogen silane monomer comprises any one or a combination of at least two of trimethylchlorosilane, trimethylbromosilane, triethylchlorosilane, triphenylchlorosilane, dimethylmonohydrosilane, phenyldimethylchlorosilane, or diphenylmethylchlorosilane;

the monohydroxy silane monomer comprises any one or a combination of at least two of trimethyl monohydroxy silane, triethyl monohydroxy silane and triphenyl monohydroxy silane;

the monoalkoxysilane monomer comprises trimethyl-monomethoxy silane and/or trimethyl-monomethoxy silane.

5. The polyvinylpyrrolidone copolymer according to claim 1, wherein the raw materials for preparing the polyvinylpyrrolidone copolymer further comprise an initiator;

the initiator comprises an organic peroxide initiator;

the organic peroxide initiator comprises any one or a combination of at least two of di-tert-amyl peroxide, di-tert-butyl peroxide, dicumyl peroxide, dibenzoyl peroxide, tert-butyl peroxybenzoate, tert-butyl peroxyethylhexanoate or tert-butyl peroxyacetate;

the mass of the initiator is 0.5-10% of the total mass of N-vinyl pyrrolidone, hydroxyl-containing monomers, amino-containing monomers and anionic monomers.

6. The method for preparing a polyvinylpyrrolidone copolymer according to any one of claims 1 to 5, characterized in that the method comprises the steps of: mixing N-vinyl pyrrolidone, hydroxyl-containing monomer, amino-containing monomer and anion monomer, reacting, and adding organosilane modifier for modification to obtain the polyvinylpyrrolidone copolymer.

7. The method of preparing according to claim 6, wherein the mixing further comprises mixing a solvent and an initiator with the N-vinyl pyrrolidone, the hydroxyl-containing monomer, the amino-containing monomer, and the anionic monomer;

the solvent comprises a hydrophilic polar solvent;

the solvent comprises any one or a combination of at least two of ethylene glycol methyl ether, ethylene glycol butyl ether, propylene glycol butyl ether, diethylene glycol methyl ether, diethylene glycol dimethyl ether, dipropylene glycol methyl ether, N-methylpyrrolidone, N-dimethylamide or dimethyl sulfoxide;

the step of mixing includes adding a mixture of N-vinylpyrrolidone, hydroxyl-containing monomer, amino-containing monomer, anionic monomer and initiator to a solvent at 90-160 ℃;

the adding mode comprises any one of one-time adding, equal-amount sectional adding or dripping adding;

the sectional addition is carried out for 2-10 times, and the time interval of each time is 30-60 min;

the dripping time is 2-5 h;

the sum of the mass percentages of the N-vinyl pyrrolidone, the hydroxyl-containing monomer, the amino-containing monomer and the anionic monomer is 40-60 percent based on 100 percent of the mass of the N-vinyl pyrrolidone, the hydroxyl-containing monomer, the amino-containing monomer and the solvent;

the reaction is carried out under nitrogen atmosphere;

the temperature of the reaction is 90-160 ℃ and the time is 1-3 h;

the modification temperature is 40-70 ℃, and the modification time is 1-5 h;

the modified method further comprises a step of neutralization, wherein the neutralization is performed by adding an alkaline substance;

the alkaline substance comprises an organic base and/or an inorganic base.

8. The method according to claim 7, wherein the alkaline substance comprises any one or a combination of at least two of ethanolamine, triethanolamine, aqueous ammonia, sodium hydroxide, and potassium hydroxide.

9. A monocrystalline silicon piece texturing additive, characterized in that the monocrystalline silicon piece texturing additive comprises the polyvinylpyrrolidone copolymer of any one of claims 1-5.

10. The monocrystalline silicon piece texturing additive of claim 9, wherein the monocrystalline silicon piece texturing additive comprises the following components in mass percent: the polyvinylpyrrolidone copolymer of any one of claims 1 to 5 0.1-2% and deionized water 98-99.9%.

11. A monocrystalline silicon piece texturing solution, characterized in that the monocrystalline silicon piece texturing solution comprises the polyvinylpyrrolidone copolymer according to any one of claims 1 to 5 or the monocrystalline silicon piece texturing additive according to claim 9.

12. The monocrystalline silicon piece texturing solution according to claim 11, wherein the monocrystalline silicon piece texturing solution comprises the following components in percentage by mass: the monocrystalline silicon piece texturing additive of claim 9, 0.1-1.5% and 98.5-99.9% of inorganic alkali solution;

the inorganic alkali solution is sodium hydroxide solution with the mass percent of 0.5-1 percent of sodium hydroxide.

13. The use of a polyvinylpyrrolidone copolymer according to any one of claims 1 to 5 for the texturing of monocrystalline silicon wafers,

the application comprises the following steps:

(1) Mixing the polyvinylpyrrolidone copolymer of any one of claims 1-5 with deionized water to obtain a monocrystalline silicon piece texturing additive;

(2) Mixing the monocrystalline silicon wafer texturing additive prepared in the step (1) with sodium hydroxide alkali solution to obtain monocrystalline silicon wafer texturing solution;

(3) Immersing the monocrystalline silicon piece into the monocrystalline silicon piece texturing liquid in the step (2) for texturing, wherein the temperature is 75-95 ℃ and the time is 4-8 min, and obtaining the textured monocrystalline silicon piece.