阅读说明：本技术 一种腐蚀液及其制备方法和应用 (Corrosive liquid and preparation method and application thereof ) 是由 张临安 邓伟伟 于 2019-11-15 设计创作，主要内容包括：本发明提供了一种腐蚀液及其制备方法和应用；所述腐蚀液包括质量百分比为0.5-4.5％的碱、0.01-0.225％的山梨酸钾、0.01-0.225％的乙酸钠、0.005-0.15％的十二烷基苯硫酸钠、0.055-0.46％的消泡剂、0.055-0.78％的表面活性剂、0.035-0.42％的分散剂、0.47-4.42％的功能性助剂以及余量的水；该腐蚀液用于基片层的制备时,能够控制基片的背面形成较均匀的金字塔型绒面,并能保证基片正面的发射极层不被破坏,且能够控制金字塔型的尺寸,使其保持较低的金字塔型的高宽比,从而降低背面绒面的比表面积,有利于背面钝化,降低复合；提高N型接触电池的太阳能转化效率。(The invention provides a corrosive liquid and a preparation method and application thereof; the corrosive liquid comprises 0.5-4.5% of alkali, 0.01-0.225% of potassium sorbate, 0.01-0.225% of sodium acetate, 0.005-0.15% of sodium dodecyl benzene sulfate, 0.055-0.46% of defoaming agent, 0.055-0.78% of surfactant, 0.035-0.42% of dispersing agent, 0.47-4.42% of functional auxiliary agent and the balance of water by mass percentage; when the corrosive liquid is used for preparing a substrate layer, the back of the substrate can be controlled to form a uniform pyramid-shaped suede, the emitter layer on the front of the substrate can be prevented from being damaged, the size of the pyramid can be controlled, and the pyramid-shaped depth-width ratio can be kept low, so that the specific surface area of the back suede is reduced, the back passivation is facilitated, and the recombination is reduced; the solar energy conversion efficiency of the N-type contact cell is improved.)

1. The corrosive liquid is characterized by comprising, by mass, 0.5-4.5% of alkali, 0.01-0.225% of potassium sorbate, 0.01-0.225% of sodium acetate, 0.005-0.15% of sodium dodecylbenzene sulfate, 0.055-0.46% of a defoaming agent, 0.055-0.78% of a surfactant, 0.035-0.42% of a dispersing agent, 0.47-4.42% of a functional auxiliary agent and the balance of water.

2. The corrosion solution according to claim 1, wherein the corrosion solution comprises, by mass, 2.4-3% of alkali, 0.0195-0.105% of potassium sorbate, 0.015-0.1% of sodium acetate, 0.012-0.075% of sodium dodecylbenzene sulfate, 0.105-0.31% of an antifoaming agent, 0.105-0.36% of a surfactant, 0.066-0.195% of a dispersant, 2.75-4.42% of a functional auxiliary agent, and the balance of water.

3. The etching solution of claim 1 or 2, wherein the base comprises sodium hydroxide and/or potassium hydroxide;

preferably, the defoamer comprises a polyether modified silicone oil and/or a polysiloxane, preferably a polydimethylsiloxane.

4. The etching solution of any one of claims 1 to 3, wherein the surfactant comprises a combination of any one or more of alkylphenol ethoxylates, fatty alcohol-polyoxyethylene ethers, propylene glycol block polyethers, or perfluoroalkyl quaternary ammonium iodides;

preferably, the dispersant comprises any one or a combination of at least two of polystyrene, polyethylene, polypropylene or sodium polyacrylate.

5. The etching solution of any one of claims 1 to 4, further comprising 0.47 to 4.42 mass% of a functional auxiliary;

preferably, the functional adjuvant comprises an oxidizing agent and/or a stabilizing agent.

6. The method of preparing the etching solution according to any one of claims 1 to 5, comprising: mixing potassium hydroxide, a texturing additive, a single-side polishing additive, deionized water and an optional functional auxiliary agent to obtain the corrosive liquid;

preferably, the mixing is performed under stirring conditions.

7. A substrate layer is characterized by comprising an N-type substrate layer, an emitter layer and a borosilicate glass layer which are sequentially arranged on the front surface of the N-type substrate layer, and a texture surface of a pyramid-shaped structure arranged on the back surface of the N-type substrate layer, wherein the texture surface of the pyramid-shaped structure is formed by etching with the etching solution according to any one of claims 1 to 5.

8. The method for producing a substrate layer according to claim 7, comprising: etching the pretreated N-type substrate by using the corrosive liquid of any one of claims 1 to 5 to obtain the substrate layer;

preferably, the etching temperature is 50-90 ℃;

preferably, the etching time is 300-;

preferably, the preparation method of the pretreated N-type substrate comprises the following steps: b diffusion is carried out on the N-type substrate of the prefabricated product, then back etching is carried out to remove the borosilicate glass layer with the back and the side being wound and expanded, and the pretreated N-type substrate is obtained;

preferably, the preform N-type substrate is double-sided textured with an N-type base layer.

9. A method of making an N-type passivated contact cell, wherein the N-type passivated contact cell is made with the substrate layer of claim 7.

10. The N-type passivated contact cell prepared according to the preparation method of claim 9.

Technical Field

The invention belongs to the field of corrosion, and relates to a corrosive liquid, and a preparation method and application thereof.

Background

The corrosion refers to that the surface of a substance is damaged due to chemical reaction when the substance is contacted with the substance, and although the corrosion can damage the surface of the substance to a certain extent, the corrosion always has two sides, and if the corrosion process is applied to a proper field and a proper environment, the corrosion process can play a corresponding role in helping life and industrial production; such as etching of glass, to obtain glass with specific patterns, such as metallographic etching, can be used for preparing alloys, or the principle of etching can be used for removing unwanted impurities or obtaining substances needed by human beings.

CN109553305A discloses a glass etching solution, which is prepared by mixing phosphate, pyrophosphate, inorganic alkali, surfactant and deionized water, and the weight fractions are respectively: 0.5-8% of phosphate, 0.5-8% of pyrophosphate, 0.01-0.5% of inorganic base, 5-45% of surfactant, 30-95% of deionized water, 20-99% of potassium difluoride and 1-80% of at least one water-soluble multivalent cation salt; the glass corrosive liquid has a good corrosion effect on glass, but the application range is too narrow, and the glass corrosive liquid is only suitable for corrosion of glass.

CN107604360A discloses a selective copper etching solution, which comprises the following components in percentage by weight: 1-20% of an oxidant, 0.001-5% of a hydrogen peroxide stabilizer, 0.01-10% of an inorganic acid, 1-4% of a soluble organic acid cupric salt, 0.01-8% of a chelating agent and/or a corrosion inhibitor, 0.001-3% of a surfactant and the balance of water, wherein the oxidant mainly comprises hydrogen peroxide; the etching liquid enables uniform etching to control the shape of the electrode, but it is only known to play a role of etching.

For an N-type passivated contact double-sided battery, the back morphology has a great influence on the double-sided rate, surface passivation and metallization contact of the battery. Therefore, it is necessary to provide an etchant that does not damage the mask layer during the fabrication of the N-type passivated contact double-sided cell and does not affect the back passivation structure.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides the corrosive liquid and the preparation method and the application thereof, and the corrosive liquid can control the back of the substrate to form a uniform pyramid suede in the process of preparing the substrate layer, can ensure that an emitter layer on the front of the substrate is not damaged, and can control the size of the pyramid to keep the height-width ratio of the pyramid to be lower, thereby reducing the specific surface area of the suede on the back, being beneficial to passivating the back and reducing the recombination; in addition, the method has a higher etching rate, and the etching process can be completed in a shorter time; the N-type contact cell comprising the substrate layer has higher solar energy conversion efficiency.

The invention aims to provide a corrosive liquid, which comprises 0.5-4.5% of alkali, 0.01-0.225% of potassium sorbate, 0.01-0.225% of sodium acetate, 0.005-0.15% of sodium dodecyl benzene sulfate, 0.055-0.46% of defoaming agent, 0.055-0.78% of surfactant, 0.035-0.42% of dispersing agent and the balance of water by mass percentage.

In the process of preparing the substrate layer, the corrosive liquid can control the back surface of the substrate to form a uniform pyramid suede, can ensure that an emitter layer on the front surface of the substrate is not damaged, and can control the size of the pyramid, so that the pyramid is kept at a lower height-to-width ratio, thereby reducing the specific surface area of the back suede, being beneficial to back passivation and reducing recombination.

In the present invention, the alkali may be 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, or the like in mass%.

In the present invention, the potassium sorbate may be 0.01%, 0.025%, 0.05%, 0.075%, 0.1%, 0.125%, 0.15%, 0.175%, 0.2%, 0.225% or the like in mass%.

In the present invention, the mass percentage of sodium acetate may be 0.01%, 0.025%, 0.05%, 0.075%, 0.1%, 0.125%, 0.15%, 0.175%, 0.2%, 0.225%, or the like.

In the present invention, the sodium dodecylbenzene sulfate may be 0.005%, 0.006%, 0.007%, 0.008%, 0.009%, 0.01%, 0.011%, 0.012%, 0.013%, 0.014%, 0.015%, or the like in mass%.

In the present invention, the defoaming agent may be 0.055%, 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, 0.46%, or the like in mass%.

In the present invention, the surfactant may be 0.055%, 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, 0.5%, 0.55%, 0.6%, 0.65%, 0.7%, 0.75%, 0.78%, or the like, in mass%.

In the present invention, the mass percentage of the dispersant may be 0.035%, 0.05%, 0.08%, 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.42%, etc.

As a preferable technical scheme of the invention, the corrosive liquid comprises 2.4-3% of alkali, 0.0195-0.105% of potassium sorbate, 0.015-0.1% of sodium acetate, 0.012-0.075% of sodium dodecyl benzene sulfate, 0.105-0.31% of defoaming agent, 0.105-0.36% of surfactant, 0.066-0.195% of dispersing agent and the balance of water by mass percent.

In the present invention, the alkali includes sodium hydroxide and/or potassium hydroxide.

In the present invention, the defoaming agent includes polyether-modified silicone oil and/or polysiloxane, preferably polydimethylsiloxane.

In the invention, the surfactant comprises one or more of alkylphenol ethoxylates, fatty alcohol-polyoxyethylene ether, propylene glycol block polyether or perfluoroalkyl quaternary ammonium iodide.

In the present invention, the dispersant includes any one or a combination of at least two of polystyrene, polyethylene, polypropylene, or sodium polyacrylate.

In the present invention, the etching solution further includes 0.47 to 4.42% by mass of a functional auxiliary, such as 0.47%, 0.5%, 0.8%, 1%, 1.2%, 1.5%, 1.7%, 2%, 2.2%, 2.5%, 2.7%, 3%, 3.2%, 3.5%, 3.7%, 4%, 4.42%, etc.

In the present invention, the functional assistant includes an oxidizing agent and/or a stabilizer.

In the invention, the functional auxiliary agent is matched with the defoaming agent, the surfactant and the dispersing agent for use, so that the suede is modified, and the emitter layer on the front side is prevented from being corroded by alkali liquor.

Another object of the present invention is to provide a method for producing the etching solution according to the first object, the method comprising: and mixing potassium hydroxide, a texturing additive, a single-side polishing additive, deionized water and an optional functional auxiliary agent to obtain the corrosive liquid.

In the present invention, the mixing is performed under stirring conditions.

The preparation method of the corrosive liquid has the advantages of easily available raw materials, low price, easy realization and convenient industrial large-scale production and application.

The invention also aims to provide a substrate layer which comprises an N-type substrate layer, an emitter layer and a borosilicate glass layer which are sequentially arranged on the front surface of the N-type substrate layer, and a texture surface of a pyramid-shaped structure arranged on the back surface of the N-type substrate layer, wherein the texture surface of the pyramid-shaped structure is formed by etching the etching solution for one purpose.

The substrate layer is applied to the N-type passivated contact battery, and the texture of the pyramid-shaped structure on the back side can solve the problem of poor back side metalized contact; the pyramid suede formed by etching the etching solution has larger pyramid size and can reduce the height-width ratio of the pyramid, thereby reducing the specific surface area of the back suede and being beneficial to back passivation; and the corrosive liquid can not damage the emitter layer on the front side in the process of etching the back side of the substrate layer; and the etching speed is high and the etching time is short in the etching process, so that the efficiency of industrial production is improved.

In the pyramid-shaped structure, the pyramid structure is directly formed on the back N-shaped substrate, the bottom of the pyramid structure is the deepest position of the pyramid, and the height of the pyramid structure refers to the vertical distance from the top of the pyramid structure to the bottom of the pyramid; the width of the pyramid shape refers to the maximum linear distance between any two points on the bottom surface of the pyramid shape.

In the present invention, the N-type substrate refers to silicon doped with an element of main group V, and illustratively includes a phosphorus-doped single crystal silicon wafer or a phosphorus-doped pseudo single crystal silicon wafer; the N-type base layer will be referred to hereinafter in the same sense.

In the present invention, it is to be understood that the terms "front" and "back" indicate orientations and positional relationships based on those shown in the drawings, which are only for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention.

A fourth object of the present invention is to provide a method for producing a substrate layer according to the third object, the method comprising: and etching the pretreated N-type substrate by using the etching solution of one of the purposes to obtain the substrate layer.

In the invention, the etching temperature is 50-90 ℃.

In the invention, the etching time is 300-1200 s.

In the invention, the preparation method of the pretreated N-type substrate comprises the following steps: and carrying out boron diffusion on the N-type substrate of the prefabricated product, and then carrying out single-side etching to obtain the pretreated N-type substrate.

In the invention, the N-type substrate of the prefabricated product is obtained by double-sided texturing of an N-type base layer.

The fifth object of the present invention is to provide a method for producing an N-type passivated contact cell produced by the substrate layer according to the third object.

The sixth purpose of the invention is to provide an N-type passivated contact battery prepared by the preparation method described in the fifth purpose.

The N-type passivated contact battery has the advantages of long minority carrier lifetime, low attenuation and high light conversion efficiency; in addition, the cell structure is also suitable for single-sided and double-sided photovoltaic modules.

In the present invention, an N-type passivated contact cell comprises:

an N-type base layer;

the emitter layer, the oxidation passivation layer, the anti-reflection layer and the front electrode layer are sequentially arranged on the front surface of the N-type substrate layer, and the front electrode layer sequentially penetrates through the anti-reflection layer and the oxidation passivation layer and is connected with the front surface of the emitter layer;

and the oxide layer, the polycrystalline silicon doping layer, the protection layer and the back electrode layer are sequentially arranged on the back surface of the N-type substrate layer, and the back electrode layer penetrates through the protection layer and is connected with the polycrystalline silicon doping layer.

In the description of the invention, it is to be noted that, unless explicitly stated or limited otherwise, the terms "connected" and "connected" are to be interpreted broadly, e.g. as a fixed connection, a detachable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art through specific situations.

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

in the process of preparing the substrate layer, the corrosive liquid can control the back surface of the substrate to form a uniform pyramid suede, can ensure that an emitter layer on the front surface of the substrate is not damaged, and can control the size of the pyramid, so that the pyramid is kept at a lower height-to-width ratio, thereby reducing the specific surface area of the back suede, being beneficial to back surface passivation and reducing compounding; in addition, the method has a higher corrosion rate, and the corrosion process can be completed in a shorter time; the N-type contact cell comprising the substrate layer has higher solar energy conversion efficiency, and the light conversion efficiency is as high as 22.97%.

Drawings

FIG. 1 is a schematic view of the structure of a substrate layer in example 1;

FIG. 2 is a scanning electron microscope image of the width of the pyramid-shaped textured surface of the back surface of the substrate layer in example 1;

FIG. 3 is a scanning electron microscope image of the pyramidal texture height of the back side of the substrate layer in example 1;

fig. 4 is a schematic diagram of an N-type passivated contact cell in accordance with an embodiment.

Detailed Description

The technical solution of the present invention is further explained by the following embodiments. It should be understood by those skilled in the art that the examples are only for the understanding of the present invention and should not be construed as the specific limitations of the present invention.

Example 1

The embodiment provides a corrosive liquid, which comprises, by mass, 2.6% of potassium hydroxide, 0.05% of potassium sorbate, 0.05% of sodium acetate, 0.05% of sodium dodecyl benzene sulfate, 0.5% of a defoaming agent (model LJ-618, manufactured by beijing ruilange), 0.2% of a surfactant (model ZJ-821, manufactured by guangzhou frontier), 0.12% of a dispersant (model ZJ-855, manufactured by guangzhou frontier) and the balance of water.

The preparation method of the corrosive liquid comprises the following steps: and stirring and mixing the raw materials to obtain the corrosive liquid.

The present embodiment further provides a substrate layer, as shown in fig. 1, including an N-type substrate layer 100, an emitter layer 101 and a borosilicate glass layer 102 sequentially disposed on the front surface of the N-type substrate layer, and a textured surface 103 of a pyramid structure disposed on the back surface of the N-type substrate layer, the textured surface being formed by etching with the etching solution.

The method for preparing the substrate layer comprises the following steps:

(1) carrying out double-sided texturing on an N-type substrate layer (a phosphorus-doped monocrystalline silicon wafer) in advance, then carrying out boron diffusion on the textured N-type substrate layer in three steps, wherein in the first step, in boron tribromide with the flow rate of 500sccm, source deposition is carried out at the temperature of 900 ℃ for 40min, in the second step, in nitrogen with the flow rate of 15slm, propulsion treatment is carried out at the temperature of 1050 ℃ for 60min, in the third step, in oxygen with the flow rate of 15slm, oxidation treatment is carried out at the temperature of 1050 ℃ for 80min, and the N-type substrate layer with an emitter layer and a borosilicate glass layer sequentially laminated on the front surface, the back surface and the side surface is obtained;

(2) removing the borosilicate glass layers wound and expanded on the back surface and the side surface of the N-type substrate layer, which is obtained in the step (1), of which the front surface, the back surface and the side surface are sequentially laminated with the emitter layer and the borosilicate glass layer by adopting HF acid corrosion with the concentration of 3 percent to obtain a pretreated N-type substrate;

(3) and (3) placing the pretreated N-type substrate obtained in the step (2) in the corrosive liquid, etching for 600s at 80 ℃, removing the emitter layer on the back and the emitter layer wound and expanded on the side, and simultaneously forming a textured surface with a pyramid structure to obtain a substrate layer.

Fig. 2 is a scanning electron microscope image of the width of the pyramid-shaped texture on the back surface of the substrate layer in the present embodiment, which shows that the width of the pyramid is 2.85 μm; FIG. 3 is a scanning electron microscope image of the pyramid-shaped texture height of the back surface of the substrate layer in this embodiment, which shows that the pyramid-shaped texture height is 1.06 μm; as can be seen from fig. 2 and 3, the texture of the pyramid-shaped structure obtained in this embodiment has a low aspect ratio of 0.37.

Example 2

The embodiment provides a corrosive liquid, which comprises, by mass, 2.4% of potassium hydroxide, 0.105% of potassium sorbate, 0.015% of sodium acetate, 0.075% of sodium dodecyl benzene sulfate, 0.105% of a defoaming agent (model LQ-0907, manufacturer tianjin kelangqi), 0.36% of a surfactant (model FP415, manufacturer guangzhou Runzi), 0.066% of a dispersant (model 5027, manufacturer Runxin chemical industry), and the balance of water.

The preparation method of the corrosive liquid comprises the following steps: and stirring and mixing the raw materials to obtain the corrosive liquid.

The embodiment also provides a substrate layer, which comprises an N-type substrate layer, an emitter layer and a borosilicate glass layer which are sequentially arranged on the front surface of the N-type substrate layer, and a texture surface of a pyramid-shaped structure arranged on the back surface of the N-type substrate layer, wherein the texture surface is formed by etching the etching liquid.

The substrate layer was prepared in the same manner as in example 1 except that the etching temperature was 50 ℃ and the etching time was 1200 seconds.

The aspect ratio of the textured surface of the pyramid-shaped structure obtained in this embodiment is 0.33.

Example 3

The embodiment provides a corrosive liquid, which comprises, by mass, 3% of potassium hydroxide, 0.0195% of potassium sorbate, 0.1% of sodium acetate, 0.012% of sodium dodecyl benzene sulfate, 0.31% of a defoaming agent (model LJ-618, beijing ruilange), 0.105% of a surfactant (model FP415, product guangzhou Runzhong), 0.195% of a dispersant (model ZJ-855, product guangzhou Zhijing), and the balance of water.

The preparation method of the corrosive liquid comprises the following steps: and stirring and mixing the raw materials to obtain the corrosive liquid.

The embodiment also provides a substrate layer, which comprises an N-type substrate layer, an emitter layer and a borosilicate glass layer which are sequentially arranged on the front surface of the N-type substrate layer, and a texture surface of a pyramid-shaped structure arranged on the back surface of the N-type substrate layer, wherein the texture surface is formed by etching the etching liquid.

The substrate layer was prepared in the same manner as in example 1 except that the etching temperature was 90 deg.c and the etching time was 300 seconds.

The aspect ratio of the textured surface of the pyramid-shaped structure obtained in this embodiment is 0.27.

Example 4

The embodiment provides a corrosive liquid, which comprises, by mass, 0.5% of sodium hydroxide, 0.225% of potassium sorbate, 0.01% of sodium acetate, 0.15% of sodium dodecylbenzene sulfate, 0.055% of a defoaming agent (model LQ-0907, manufacturer tianjin kelangqi), 0.78% of a surfactant (model ZJ-821, manufacturer guangzhou border-stopper), 0.035% of a dispersant (model 5027, manufacturer Runxin chemical industry), and the balance of water.

The preparation method of the corrosive liquid comprises the following steps: and stirring and mixing the raw materials to obtain the corrosive liquid.

The embodiment also provides a substrate layer, which comprises an N-type substrate layer, an emitter layer and a borosilicate glass layer which are sequentially arranged on the front surface of the N-type substrate layer, and a texture surface of a pyramid-shaped structure arranged on the back surface of the N-type substrate layer, wherein the texture surface is formed by etching the etching liquid.

The substrate layer was prepared in the same manner as in example 1 except that the etching temperature was 80 ℃ and the etching time was 500 seconds.

The aspect ratio of the textured surface of the pyramid-shaped structure obtained in this embodiment is 0.23.

Example 5

The embodiment provides a corrosive liquid, which comprises, by mass, 4.5% of sodium hydroxide, 0.01% of potassium sorbate, 0.225% of sodium acetate, 0.005% of sodium dodecylbenzene sulfate, 0.46% of a defoaming agent (model LJ-618, manufactured by beijing ruilange), 0.055% of a surfactant (model ZJ-821, manufactured by guangzhou tang), 0.42% of a dispersing agent (model ZJ-855, manufactured by guangzhou tang) and the balance of water.

The preparation method of the corrosive liquid comprises the following steps: and stirring and mixing the raw materials to obtain the corrosive liquid.

The embodiment also provides a substrate layer, which comprises an N-type substrate layer, an emitter layer and a borosilicate glass layer which are sequentially arranged on the front surface of the N-type substrate layer, and a texture surface of a pyramid-shaped structure arranged on the back surface of the N-type substrate layer, wherein the texture surface is formed by etching the etching liquid.

The substrate layer was prepared in the same manner as in example 1 except that the etching temperature was 60 ℃ and the etching time was 1000 seconds.

The aspect ratio of the textured surface of the pyramid-shaped structure obtained in this embodiment is 0.38.

Comparative example 1

The etching solution used in this comparative example was a mixture of hydrofluoric acid having a concentration of 7% and nitric acid having a concentration of 24%.

The method for preparing the substrate layer comprises the following steps: the N-type base layer obtained in step (1) in example 1, in which the emitter layer and the borosilicate glass layer were sequentially laminated on the front surface, the back surface, and the side surfaces, was etched with hydrofluoric acid having a concentration of 7% and nitric acid having a concentration of 24% to remove the emitter layer and the borosilicate glass layer having been diffracted on the back surface and the side surfaces, thereby obtaining a substrate layer.

The back surface obtained in the comparative example is a relatively flat polished-like back surface structure, and a pyramid-shaped structure is difficult to form.

Comparative example 2

The only difference from example 1 is that sodium acetate is not included, the amount of sodium dodecylbenzene sulfate added is the same as that of example 1, and the remaining composition and preparation method are the same as those of example 1.

The aspect ratio of the texture of the pyramid-shaped structure obtained in the comparative example was 0.48; as can be seen from a comparison between comparative example 2 and example 1, the pyramid structure obtained in example 1 has a lower aspect ratio.

Comparative example 3

The only difference from example 1 is that sodium dodecylbenzene sulfate was not included, sodium acetate was added in the same amount as in example 1, and the remaining composition and preparation method were the same as in example 1.

The aspect ratio of the texture of the pyramid-shaped structure obtained in the comparative example was 0.55; as can be seen from a comparison between comparative example 3 and example 1, the pyramid structure obtained in example 1 has a lower aspect ratio.

Comparative example 4

The difference from example 1 is that potassium sorbate is not included, and the remaining composition and preparation method are the same as those of example 1.

The aspect ratio of the texture of the pyramid-shaped structure obtained in the comparative example was 0.47; as can be seen from a comparison between comparative example 4 and example 1, the pyramid structure obtained in example 1 has a lower aspect ratio.

Comparative example 5

The difference from example 1 is only in the composition of the etching solution, which includes: 2% of potassium hydroxide, 0.5% of potassium sorbate, 0.005% of sodium acetate, 0.3% of sodium dodecyl benzene sulfonate, 0.02% of defoaming agent, 0.9% of surfactant, 0.02% of dispersant and the balance of water.

The aspect ratio of the texture of the pyramid-shaped structure obtained in the comparative example was 0.51; as can be seen from a comparison between comparative example 5 and example 1, the pyramid structure obtained in example 1 has a lower aspect ratio.

Comparative example 6

The difference from example 1 is only in the composition of the etching solution, which includes: 5% of potassium hydroxide, 0.005% of potassium sorbate, 0.3% of sodium acetate, 0.001% of sodium dodecyl benzene sulfonate, 0.5% of defoaming agent, 0.03% of surfactant, 0.5% of dispersing agent and the balance of water.

The aspect ratio of the texture of the pyramid-shaped structure obtained in the comparative example was 0.43; as can be seen from a comparison of comparative example 6 and example 1, the pyramid structure obtained in example 1 has a lower aspect ratio.

The substrate layers of examples 1-5 and comparative examples 1-6 were prepared to produce N-type passivated contact cells, as shown in fig. 4, comprising: an N-type substrate layer 1; the emitter layer 2, the oxidation passivation layer 3, the anti-reflection layer 4 and the front electrode layer 5 are arranged on the front surface of the N-type substrate layer and are sequentially connected, and the front electrode layer 5 sequentially penetrates through the anti-reflection layer 4 and the oxidation passivation layer 3 and is connected with the emitter layer 2; the oxide layer 6, the polycrystalline silicon doping layer 7, the protection layer 8 and the back electrode layer 9 are arranged on the back surface of the N-type substrate layer 1 and are sequentially connected, and the back electrode layer 9 penetrates through the protection layer 8 and is connected with the polycrystalline silicon doping layer 7; the oxidation passivation layer is an aluminum oxide passivation layer; the thickness of the aluminum oxide passivation layer is 10 nm; the anti-reflection layer is a silicon nitride anti-reflection layer; the thickness of the antireflection layer is 100 nm; the refractive index of the anti-reflection layer is 2.02; the front electrode layer is an Ag-Al electrode layer; the thickness of the front electrode layer is 20 μm; the oxide layer is a silicon oxide layer; the thickness of the silicon oxide layer is 2 nm; the thickness of the polycrystalline silicon doping layer is 200 nm; the protective layer is a silicon nitride layer; the thickness of the silicon nitride layer is 100 nm; the back electrode layer is a silver electrode layer; the thickness of the silver electrode layer was 10 μm.

The preparation method of the N-type passivated contact battery comprises the following steps:

s1, oxidizing the back surface of the substrate layer with nitric acid for 10min, then performing thermal oxidation for 10min at the temperature of 580 ℃ to obtain an N-type substrate layer with an oxide layer on the back surface, then depositing polycrystalline silicon on the surface of the oxide layer by a chemical vapor deposition method under the condition that the pressure is 300mTorr, performing phosphorus diffusion in three steps under the condition that a phosphorus source is phosphorus oxychloride, performing first source-through deposition for 30min at 750 ℃ in phosphorus oxychloride with the flow of 500sccm in the first step, performing propulsion treatment for 40min at 900 ℃ in nitrogen with the flow of 3000sccm in the second step, performing second source-through deposition for 5min at 770 ℃ in phosphorus oxychloride with the flow of 300sccm in the third step, and obtaining the N-type substrate layer with the doped layer;

s2, removing the phosphorosilicate glass layer on the front surface of the N-type substrate layer with the doped layer obtained in the step S1 through a first etching method by using a hydrofluoric acid solution with the concentration of 5%, then removing the polycrystalline silicon wound and plated on the front surface of the N-type substrate layer with the doped layer through a potassium hydroxide solution with the concentration of 20%, and finally removing the borosilicate glass layer on the front surface of the N-type substrate layer with the doped layer and the phosphorosilicate glass layer on the back surface through a second etching method by using a hydrofluoric acid solution with the concentration of 10% to obtain the N-type substrate layer with the silicon oxide layer and the polycrystalline silicon doped layer on the back surface;

s3, firstly forming an aluminum oxide passivation layer with the thickness of 5nm on the front side of the processed N-type substrate layer with the silicon oxide layer and the N-type polycrystalline silicon layer on the back side obtained in the step S2 through an atomic layer deposition method, then forming a silicon nitride antireflection layer with the thickness of 80nm and the refractive index of 2.02 through a plasma chemical vapor deposition method, and forming a silicon nitride protection layer with the thickness of 120nm on the back side through the plasma chemical vapor deposition method to obtain the N-type substrate layer with a passivation structure;

and S4, screen printing the N-type base layer with the passivation structure obtained in the step S3, and then sintering at 800 ℃ for 60S to form a front Ag-Al electrode layer and a back Ag electrode layer, so that the N-type passivation contact battery is obtained.

The obtained N-type passivated contact cell was subjected to performance testing, the test results are shown in table 1:

TABLE 1

In table 1:

wherein, the voltage (V), the current (A) and the filling factor (%) are the corresponding voltage, current and filling factor given in the table 1; the area of the battery is 244.32 square centimeters; the voltage (V) and the current (A) are the voltage and the current generated by the battery under the irradiation of 1000W light intensity, the model of the adopted testing machine is German Halm-2400, and the model of the testing software is 18-KW 05; the fill factor is the ratio of the maximum output power of the battery to the product of the short circuit current and the open circuit voltage.

As can be seen from table 1, the passivated contact cells prepared according to the present invention have higher light conversion efficiency; as can be seen from the comparison between example 1 and comparative example 1, the back structure obtained by acid etching is similar to a polished flat structure, and the open-circuit voltage and the short-circuit current are higher in the aspect of electrical properties, but the filling factor is lower and the efficiency is lower; as can be seen from the comparison between the example 1 and the comparative examples 2 to 3, the suede can be modified by the sodium acetate and the sodium dodecyl benzene sulfate which are used together, the height-width ratio is reduced, and the open-circuit voltage and the short-circuit current of the battery are improved; from the comparison between the embodiment 1 and the comparative example 4, the potassium sorbate can modify the suede surface to a certain extent, reduce the aspect ratio and improve the open-circuit voltage and the short-circuit current of the battery; as can be seen from the comparison between the embodiment 1 and the comparative examples 5 to 6, the suede structure with a low aspect ratio can be obtained by optimizing the proportion of the corrosive liquid, and the open-circuit voltage and the short-circuit current of the battery can be improved, so that the conversion efficiency of the battery is improved.

The applicant declares that the above description is only a specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and it should be understood by those skilled in the art that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are within the scope and disclosure of the present invention.