Silicon wafer for solar cells and method for texturing the same, optoelectronic device and photovoltaic system

Abstract

The application provides a silicon wafer for a solar cell, a texturing method thereof, a photoelectric device and a photovoltaic system, and relates to the technical field of crystalline silicon solar cells. The texturing method comprises the following steps: performing first texturing on a silicon wafer by using a first texturing solution to obtain a first target silicon wafer; and performing second texturing on the first target silicon wafer by using a second texturing solution to form a pyramid-type texturing structure with a curved surface structure on the side surface. The mass concentration of alkali in the first texturing solution is higher than that in the second texturing solution. The mass concentration of a first texturing additive in the first texturing solution is higher than that in the second texturing solution. The temperature of the first texturing is lower than that of the second texturing. The technical scheme can improve the interaction between the texturing solution and the silicon wafer, improve the uniformity of the pyramid-type texturing structure, make the lines of the pyramid-type texturing structure more round, and make the curved pyramid-type texturing structure not easy to break, thereby reducing the silicon wafer fragment rate and improving the long-term stability and reliability of the solar cell.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of crystalline silicon solar cell, in particular to a silicon wafer for solar cell, a texturing method thereof, a photoelectric device and a photovoltaic system. BACKGROUND

[0002] The texturing of silicon wafer is a very important step in the process of manufacturing crystalline silicon solar cell, and its main purpose is to form a specific microstructure on the surface of the silicon wafer to improve the performance of the cell. The silicon wafer is usually textured by alkali pyramid etching method to form a random pyramid structure. The pyramid textured surface formed on the surface of the silicon wafer can reduce the reflection of sunlight, increase the absorption of light, and help to improve the photoelectric conversion efficiency of the cell.

[0003] However, when the silicon wafer is bent after being textured by the conventional method to form a pyramid textured surface structure, the pyramid textured surface structure is easily broken, the fragment rate is high, and thus the long-term stability and reliability of the solar cell are affected.

[0004] It should be noted that the above content is not necessarily prior art, and is not used to limit the patent protection scope of the present application. SUMMARY

[0005] In view of the deficiencies of the prior art, the purpose of the present application is to provide a silicon wafer for solar cell, a texturing method thereof, a photoelectric device and a photovoltaic system. The silicon wafer is sequentially subjected to first texturing and second texturing, and the process parameters of the first texturing and the second texturing are controlled. The interaction between the texturing solution and the silicon wafer can be improved, the uniformity of the pyramid textured surface structure can be improved, the pyramid textured surface structure can be modified, the lines of the pyramid textured surface structure are more rounded, the pyramid textured surface structure with curved surface structure on the side is formed, the curved pyramid textured surface structure is not easily broken when the silicon wafer is bent, the silicon wafer fragment rate is reduced, and thus the long-term stability and reliability of the solar cell are improved.

[0006] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0007] The texturing method of the silicon wafer for solar cell comprises:

[0008] The first texturing liquid is used to perform first texturing on the silicon wafer to obtain a first target silicon wafer; the first texturing liquid comprises a first alkali solution and a first texturing additive;

[0009] The second texturing liquid is used to perform second texturing on the first target silicon wafer to form a pyramid textured surface structure with curved surface structure on the side, i.e. the silicon wafer for solar cell; the second texturing liquid comprises a second alkali solution and a second texturing additive;

[0010] The mass concentration of the alkali in the first texturing liquid is higher than the mass concentration of the alkali in the second texturing liquid; the mass concentration of the first texturing additive in the first texturing liquid is higher than the mass concentration of the second texturing additive in the second texturing liquid; and the temperature of the first texturing is lower than the temperature of the second texturing.

[0011] In some embodiments, the mass concentration of the first texturing additive in the first texturing liquid is 0.5-1.5%; and / or

[0012] The mass concentration of the second texturing additive in the second texturing liquid is 0.1-0.5%.

[0013] In some embodiments, the mass concentration of the alkali in the first texturing liquid is 0.5-5%; and / or

[0014] The mass concentration of the alkali in the second texturing liquid is 0.2-1.5%.

[0015] In some embodiments, the sum of the time of the first texturing and the time of the second texturing is 400-500s;

[0016] In some embodiments, the temperature of the first texturing is controlled at 70-85℃, and the time of the first texturing is controlled at 60-400s; and / or

[0017] The temperature of the second texturing is controlled at 85-90℃, and the time of the second texturing is controlled at 10-500s.

[0018] In some embodiments, the first texturing additive comprises isopropyl alcohol and an additive; and the second texturing additive comprises isopropyl alcohol and an additive.

[0019] In some embodiments, the mass concentration of the isopropyl alcohol in the first texturing additive is denoted as W1, and the mass concentration of the additive in the first texturing additive is denoted as W2.

[0020] The mass concentration of the isopropyl alcohol in the second texturing additive is denoted as W1', and the mass concentration of the additive in the second texturing additive is denoted as W2'; W1 and W1' satisfy: W1>W1'; and W2 and W2' satisfy: W2

[0021] In some embodiments, the texturing method further comprises: before the second texturing of the first target silicon wafer, washing the first target silicon wafer with alkali; and / or

[0022] After the second texturing of the first target silicon wafer, washing the first target silicon wafer with alkali.

[0023] The application also provides a silicon wafer for solar cells, which is prepared by the above method.

[0024] The application also provides a photoelectric device comprising the above silicon wafer for solar cells.

[0025] In some embodiments, the photoelectric device comprises a crystalline silicon solar cell.

[0026] The application also provides a photovoltaic system comprising the above photoelectric device.

[0027] In the technical solution of the application, the silicon wafer is sequentially subjected to first texturing and second texturing, and the process parameters of the first texturing and the second texturing are controlled, so that the interaction between the texturing solution and the silicon wafer is improved, the uniformity of the pyramid-shaped textured surface structure is improved, the pyramid-shaped textured surface structure is modified, the lines of the pyramid-shaped textured surface structure are smoother, the pyramid-shaped textured surface structure with a curved surface structure is formed, the curved pyramid-shaped textured surface structure is not easy to break when the silicon wafer is bent, the silicon wafer breakage rate is reduced, and the long-term stability and reliability of the solar cell are improved. BRIEF DESCRIPTION OF DRAWINGS

[0028] In the drawings, like reference numerals designate like or similar elements throughout the several views. The drawings are not necessarily to scale, the emphasis instead being placed upon illustrating the principles of the application. It should be understood that the drawings are merely depictions of some embodiments of the application and should not be interpreted in a limiting sense.

[0029] Figure 1 The straight surface state schematic diagram and the bent state schematic diagram of the pyramid-shaped textured surface structure prepared in Comparative Example 1 of the application are shown in the figure.

[0030] Figure 2 The straight surface state schematic diagram and the bent state schematic diagram of the pyramid-shaped textured surface structure prepared in the example of the application are shown in the figure. DETAILED DESCRIPTION

[0031] Embodiments of the application are described in detail below, examples of which are shown in the accompanying drawings. In the drawings, the size and relative sizes of layers, regions, elements, and the like can be exaggerated for clarity. Identical or similar components are denoted by identical or similar reference numerals throughout the drawings. The embodiments described below are exemplary and are intended to explain the application, but should not be interpreted as limiting the application. It should be noted that the embodiments in the application and the features in the embodiments can be combined with each other without conflict.

[0032] It will be understood that when an element or layer is referred to as being "on" or "connected to" another element or layer, it can be directly on or connected to the other element or layer or intervening elements or layers can be present. In contrast, when an element is referred to as being "directly on" or "directly connected to" another element, there are no intervening elements or layers present. It will be understood that, although the terms first, second, third, etc. can be used herein to describe various elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the present application. Similarly, a second element, component, region, layer or section discussed below could be termed a first element, component, region, layer or section without departing from the teachings of the present application.

[0033] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting", "fixing" and the like should be understood in a broad sense, for example, can be fixedly connected, or can be detachably connected, or can be integrated; can be mechanically connected, or can be electrically connected; can be directly connected, or can be indirectly connected through an intermediate medium; can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise explicitly limited. For those skilled in the art, the specific meaning of the above-mentioned terms in the present application can be understood according to the specific circumstances.

[0034] It should be noted that the terms "first", "second", and so on in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily describe a specific order or sequence. It should be understood that the terms used in this way can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not necessarily limit to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0035] In the present application, when a numerical interval (i.e., a numerical range) is involved, the distribution of the optional numbers in the numerical interval is considered to be continuous and includes both numerical endpoints (i.e., the minimum value and the maximum value) of the numerical interval and each number between the two numerical endpoints, unless otherwise specified. When a numerical interval refers only to integers within the numerical interval, including both endpoint integers and each integer between the two endpoints, it is equivalent to directly listing each integer, unless otherwise specified. When multiple numerical ranges are provided to describe a feature or a characteristic, the numerical ranges can be combined. In other words, unless otherwise indicated, the numerical ranges disclosed in the present application should be understood to include any and all sub-ranges therein. The "numbers" in the numerical interval can be any quantitative value, such as a number, a percentage, a ratio, etc. The "numerical interval" is intended to broadly include quantitative intervals such as percentage intervals, ratio intervals, and value intervals.

[0036] The embodiments of the present application aim to provide a silicon wafer for solar cells, a texturing method thereof, a photoelectric device, and a photovoltaic system. In the technical solution of the present application, the silicon wafer is sequentially subjected to first texturing and second texturing, and the process parameters of the first texturing and the second texturing are controlled, so as to improve the interaction between the texturing solution and the silicon wafer, improve the uniformity of the pyramid-shaped textured surface structure, and further modify the pyramid-shaped textured surface structure, so that the lines of the pyramid-shaped textured surface structure are more rounded, and a pyramid-shaped textured surface structure with a curved surface structure is formed. When the silicon wafer is bent, the curved pyramid-shaped textured surface structure is not easy to break, thereby reducing the silicon wafer fragment rate and further improving the long-term stability and reliability of the solar cell. In addition, the curved pyramid-shaped textured surface structure can further reduce light loss and further improve the light absorption effect. Moreover, the functional layers such as PN junction, passivation layer, and anti-reflection film are more easily and uniformly laid on the surface of the curved pyramid-shaped textured surface structure, the connection tightness between the functional layers and the curved pyramid-shaped textured surface structure is higher, and the photoelectric conversion efficiency of the cell is effectively improved.

[0037] The embodiments of the present application provide a texturing method of a silicon wafer for solar cells, which comprises the following steps:

[0038] The first texturing liquid comprises a first alkaline solution and a first texturing additive.

[0039] The second texturing liquid comprises a second alkaline solution and a second texturing additive.

[0040] The mass concentration of the alkali in the first texturing solution is higher than the mass concentration of the alkali in the second texturing solution; the mass concentration of the first texturing additive in the first texturing solution is higher than the mass concentration of the second texturing additive in the second texturing solution; and the temperature of the first texturing is lower than the temperature of the second texturing.

[0041] In the embodiments of the present application, the type of the silicon wafer for solar cells can be single crystal silicon or polycrystalline silicon. The texturing method of the silicon wafer for solar cells can be used for single-side texturing or double-side texturing, and single-side texturing or double-side texturing can be selected according to actual needs. In the embodiments of the present application, the first alkali solution can be a sodium hydroxide solution or a potassium hydroxide solution, the second alkali solution can be a sodium hydroxide solution or a potassium hydroxide solution, and the first alkali solution and the second alkali solution can be the same or different. In addition, the first texturing additive and the second texturing additive can be the same or different.

[0042] In the embodiments of the present application, the silicon wafer is sequentially subjected to the first texturing and the second texturing, and the process parameters of the first texturing and the second texturing are controlled, so as to improve the interaction between the texturing solution and the silicon wafer, improve the uniformity of the pyramid-shaped textured structure, and also modify the pyramid-shaped textured structure, so that the lines of the pyramid-shaped textured structure are more rounded, the pyramid-shaped textured structure with curved surface structure is formed, the curved pyramid-shaped textured structure is not easy to break when the silicon wafer is bent, which reduces the silicon wafer fragment rate, and further improves the long-term stability and reliability of the solar cell. In addition, the curved pyramid-shaped textured structure can further reduce light loss, and further improve the light absorption effect. Moreover, the connection tightness between each functional layer and the curved pyramid-shaped textured structure is higher, and thus the photoelectric conversion efficiency of the cell can be effectively improved.

[0043] In optional embodiments, the mass concentration of the first texturing additive in the first texturing solution is 0.5-1.5% (for example, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%); and / or

[0044] The mass concentration of the second texturing additive in the second texturing solution is 0.1-0.5% (for example, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%).

[0045] In the embodiments of the present application, the concentration of the texturing additive in the texturing solution is optimized, which can improve the interaction between the texturing solution and the silicon wafer, form a higher reaction rate difference between the top and bottom of the pyramid, help to modify the pyramid texture structure, make the lines of the pyramid texture structure more rounded, form a pyramid texture structure with curved surface structure on the side surface, and the curved pyramid texture structure is not easy to break when the silicon wafer is bent, which can further reduce the silicon wafer fragment rate, and further improve the long-term stability and reliability of the solar cell. In addition, the curved pyramid texture structure can further reduce the light loss, and further improve the light absorption effect.

[0046] In optional embodiments, the mass concentration of the alkali in the first texturing solution is 0.5-5% (for example, 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, 4.0%, 4.5%, 5.0%); and / or

[0047] The mass concentration of the alkali in the second texturing solution is 0.2-1.5% (for example, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%).

[0048] In the embodiments of the present application, the concentration of the alkali in the texturing solution is optimized, which can improve the interaction between the texturing solution and the silicon wafer, form a higher reaction rate difference between the top and bottom of the pyramid, help to modify the pyramid texture structure, make the lines of the pyramid texture structure more rounded, form a pyramid texture structure with curved surface structure on the side surface, and the curved pyramid texture structure is not easy to break when the silicon wafer is bent, which can further reduce the silicon wafer fragment rate, and further improve the long-term stability and reliability of the solar cell. In addition, the curved pyramid texture structure can further reduce the light loss, and further improve the light absorption effect.

[0049] In optional embodiments, the sum of the first texturing time and the second texturing time is 400-500s (for example, 400s, 410s, 420s, 430s, 440s, 450s, 460s, 470s, 480s, 490s, 500s);

[0050] In the embodiments of the present application, the concentration of the alkali in the texturing solution is optimized, which can improve the interaction between the texturing solution and the silicon wafer, form a higher reaction rate difference between the top and bottom of the pyramid, help to modify the pyramid texture structure, make the lines of the pyramid texture structure more rounded, form a pyramid texture structure with curved surface structure on the side surface, and the curved pyramid texture structure is not easy to break when the silicon wafer is bent, which can further reduce the silicon wafer fragment rate, and further improve the long-term stability and reliability of the solar cell. In addition, the curved pyramid texture structure can further reduce the light loss, and further improve the light absorption effect.

[0051] When the first target silicon wafer is subjected to the second texturing, the temperature is controlled at 85-90℃ (for example, 80℃, 81℃, 82℃, 83℃, 84℃, 85℃, 86℃, 87℃, 88℃, 89℃, 90℃), and the time is controlled at 10-500s (for example, 10s, 50s, 100s, 150s, 200s, 250s, 300s, 350s, 400s, 450s, 500s).

[0052] In the embodiments of the present application, the temperature for optimizing texturing can improve the interaction between the texturing solution and the silicon wafer, so that a higher difference in reaction rate is formed between the top of the pyramid and the bottom of the pyramid, which helps to modify the pyramid-shaped texturing structure, so that the lines of the pyramid-shaped texturing structure are smoother, and a pyramid-shaped texturing structure with curved surface structure is formed on the side surface. When the silicon wafer is bent, the curved pyramid-shaped texturing structure is not easy to break, which further reduces the silicon wafer fragment rate, and further improves the long-term stability and reliability of the solar cell. It can also further reduce the light loss, and further improve the light absorption effect.

[0053] In optional embodiments, the first texturing additive comprises isopropyl alcohol and an additive; and the second texturing additive comprises isopropyl alcohol and an additive.

[0054] In the first texturing additive, the mass concentration of isopropyl alcohol is denoted as W1, and the mass concentration of the additive is denoted as W2.

[0055] In the second texturing additive, the mass concentration of isopropyl alcohol is denoted as W1', and the mass concentration of the additive is denoted as W2'. W1 and W1' satisfy W1>W1'; and W2 and W2' satisfy W2

[0056] It should be noted that the classic formula of the texturing additive is as follows: the texturing additive comprises, by mass percentage, 0.1%-3% of sodium hydroxide, 2%-10% of isopropyl alcohol, 0.01%-2% of an additive, and the balance of water, totaling 100%; wherein the additive comprises, by mass percentage, 0.001%-3% of glucose, sodium gluconate or potassium gluconate, 100 ppb-8000 ppb of polyoxyethylene ether, 0.001%-2% of sodium lactate or sodium citrate, 0.001%-2% of propylene glycol, 0.01%-6% of sodium silicate, 0.001%-2% of sodium carbonate or sodium bicarbonate, and the balance of water, totaling 100%. In the embodiments of the present application, the content of isopropyl alcohol and the additive in the texturing additive is optimized, which can improve the interaction between the texturing solution and the silicon wafer, form a higher reaction rate difference between the top and bottom of the pyramid, help to modify the pyramid structure, make the lines of the pyramid structure more rounded, form a pyramid structure with curved surface structure on the side surface, and when the silicon wafer is bent, the curved pyramid structure is not easy to break, which can further reduce the silicon wafer breakage rate, and further improve the long-term stability and reliability of the solar cell. It can also further reduce the light loss, and further improve the light absorption effect.

[0057] In optional embodiments, the texturing method further comprises: before the second texturing of the first target silicon wafer, performing an alkali cleaning on the first target silicon wafer after the first texturing of the silicon wafer; and / or

[0058] After the second texturing of the first target silicon wafer, performing an alkali cleaning on the first target silicon wafer.

[0059] In the embodiments of the present application, the alkali cleaning of the silicon wafer can effectively remove the impurities on the surface of the silicon wafer, and improve the cleanliness of the prepared silicon wafer.

[0060] The following specific embodiments further illustrate the present application, but should not be construed as limiting the present application. Modifications or replacements of the methods, steps or conditions of the present application, without departing from the spirit and essence of the present application, all belong to the scope of the present application.

[0061] Embodiment 1

[0062] The texturing method of the silicon wafer for solar cells comprises:

[0063] (1) Pre-cleaning: a single crystal silicon wafer with a thickness of 150 μm is placed in a mixed solution of NaOH+H2O2 for pre-cleaning, and a damage layer and impurities on the surface of the silicon wafer are removed by rough polishing to obtain a pre-cleaned silicon wafer;

[0064] (2) First water cleaning: the pre-cleaned silicon wafer is cleaned with pure water to obtain a first water cleaned silicon wafer;

[0065] (3) first texturing: using a first texturing solution to texturize the once washed silicon wafer, the temperature is controlled at 70℃, the time is controlled at 60s, to obtain a first target silicon wafer; the first texturing solution comprises a first alkali solution and a first texturing additive, the mass concentration of the first texturing additive in the first texturing solution is 0.5%; the first alkali solution is a sodium hydroxide solution, the mass concentration of sodium hydroxide in the first texturing solution is 0.5%; the model of the first texturing additive is Shichuang TS50;

[0066] (4) first alkali washing: putting the first target silicon wafer into a mixed solution of NaOH+H2O2 for alkali washing to remove the impurities on the surface of the silicon wafer, to obtain a once alkali washed silicon wafer;

[0067] (5) second texturing: using a second texturing solution to texturize the once alkali washed silicon wafer, the temperature is controlled at 85℃, the time is controlled at 440s, to obtain a twice texturized silicon wafer; the second texturing solution comprises a second alkali solution and a second texturing additive, the mass concentration of the second texturing additive in the second texturing solution is 0.1%; the second alkali solution is a sodium hydroxide solution, the mass concentration of sodium hydroxide in the second texturing solution is 0.2%; the model of the second texturing additive is Shichuang TS50;

[0068] (6) second alkali washing: putting the twice texturized silicon wafer into a mixed solution of NaOH+H2O2 for alkali washing to remove the impurities on the surface of the silicon wafer, to obtain a twice alkali washed silicon wafer;

[0069] (7) second water washing: using pure water to clean the alkali solution on the surface of the twice alkali washed silicon wafer, to obtain a twice water washed silicon wafer;

[0070] (8) acid washing: using hydrofluoric acid to wash the twice water washed silicon wafer, to remove metal impurities and make the silicon wafer more easily dehydrated, to obtain an acid washed silicon wafer;

[0071] (9) third water washing: using pure water to clean the hydrofluoric acid on the surface of the acid washed silicon wafer, to obtain a thrice water washed silicon wafer;

[0072] (10) drying: drying the thrice water washed silicon wafer to obtain the silicon wafer for solar cells; the pyramid textured surface structure of the silicon wafer for solar cells in straight face state and curved state is shown in FIG. 1. Figure 2

[0073] Example 2

[0074] The texturing method of the silicon wafer for solar cells comprises:

[0075] (1) pre-washing: putting a single crystal silicon wafer with a thickness of 150μm into a mixed solution of NaOH+H2O2 for pre-washing, rough polishing to remove the damage layer and the impurities on the surface of the silicon wafer, to obtain a pre-washed silicon wafer; ​

[0076] (2) first water washing: using pure water to clean the pre-washed silicon wafer to obtain a first water washed silicon wafer;

[0077] (3) first texturing: using a first texturing solution to perform first texturing on the first water washed silicon wafer, wherein the temperature is controlled at 85°C and the time is controlled at 400s to obtain a first target silicon wafer; the first texturing solution comprises a first alkali solution and a first texturing additive, the mass concentration of the first texturing additive in the first texturing solution is 1.5%; the first alkali solution is a potassium hydroxide solution, the mass concentration of potassium hydroxide in the first texturing solution is 5%; the model of the first texturing additive is Shichuang TS52;

[0078] (4) first alkali washing: placing the first target silicon wafer into a mixed solution of NaOH+H2O2 for alkali washing to remove impurities on the surface of the silicon wafer to obtain a first alkali washed silicon wafer;

[0079] (5) second texturing: using a second texturing solution to perform second texturing on the first alkali washed silicon wafer, wherein the temperature is controlled at 90°C and the time is controlled at 50s to obtain a second texturing silicon wafer; the second texturing solution comprises a second alkali solution and a second texturing additive, the mass concentration of the second texturing additive in the second texturing solution is 0.5%; the second alkali solution is a potassium hydroxide solution, the mass concentration of potassium hydroxide in the second texturing solution is 1.5%; the model of the second texturing additive is Shichuang TS52;

[0080] (6) second alkali washing: placing the second texturing silicon wafer into a mixed solution of NaOH+H2O2 for alkali washing to remove impurities on the surface of the silicon wafer to obtain a second alkali washed silicon wafer;

[0081] (7) second water washing: using pure water to clean the alkali solution on the surface of the second alkali washed silicon wafer to obtain a second water washed silicon wafer;

[0082] (8) acid washing: using hydrofluoric acid to perform acid washing on the second water washed silicon wafer to remove metal impurities and make the silicon wafer more easily dehydrated to obtain an acid washed silicon wafer;

[0083] (9) third water washing: using pure water to clean the hydrofluoric acid on the surface of the acid washed silicon wafer to obtain a third water washed silicon wafer;

[0084] (10) drying: drying the third water washed silicon wafer to obtain the silicon wafer for solar cells; the pyramid textured surface structure of the silicon wafer for solar cells in a straight state and a curved state is shown in FIG. 1. Figure 2

[0085] Example 3

[0086] The method for texturing a silicon wafer for solar cells comprises:

[0087] ​(1) Pre-cleaning: a single crystal silicon wafer with a thickness of 150 μm is put into a mixed solution of NaOH+H2O2 for pre-cleaning, and a damaged layer and impurities on the surface of the silicon wafer are removed by rough polishing to obtain a pre-cleaned silicon wafer;

[0088] (2) First water washing: the pre-cleaned silicon wafer is cleaned with pure water to obtain a first water-washed silicon wafer;

[0089] (3) First texturing: the first water-washed silicon wafer is subjected to first texturing using a first texturing solution, wherein the temperature is controlled at 75℃ and the time is controlled at 200s to obtain a first target silicon wafer; the first texturing solution comprises a first alkali solution and a first texturing additive, the mass concentration of the first texturing additive in the first texturing solution is 0.8%, the first alkali solution is a sodium hydroxide solution, the mass concentration of sodium hydroxide in the first texturing solution is 2%, and the type of the first texturing additive is Shichuang TS50;

[0090] (4) First alkali washing: the first target silicon wafer is put into a mixed solution of NaOH+H2O2 for alkali washing to remove impurities on the surface of the silicon wafer to obtain a first alkali-washed silicon wafer;

[0091] (5) Second texturing: the first alkali-washed silicon wafer is subjected to second texturing using a second texturing solution, wherein the temperature is controlled at 87℃ and the time is controlled at 200s to obtain a second-textured silicon wafer; the second texturing solution comprises a second alkali solution and a second texturing additive, the mass concentration of the second texturing additive in the second texturing solution is 0.3%, the second alkali solution is a potassium hydroxide solution, the mass concentration of potassium hydroxide in the second texturing solution is 0.7%, and the type of the second texturing additive is Shichuang TS52;

[0092] (6) Second alkali washing: the second-textured silicon wafer is put into a mixed solution of NaOH+H2O2 for alkali washing to remove impurities on the surface of the silicon wafer to obtain a second alkali-washed silicon wafer;

[0093] (7) Second water washing: the second alkali-washed silicon wafer is cleaned with pure water to remove the alkali solution on the surface of the silicon wafer to obtain a second water-washed silicon wafer;

[0094] (8) Acid washing: the second water-washed silicon wafer is subjected to acid washing with hydrofluoric acid to remove metal impurities and make the silicon wafer more easily dehydrated to obtain an acid-washed silicon wafer;

[0095] (9) Third water washing: the acid-washed silicon wafer is cleaned with pure water to remove the hydrofluoric acid on the surface of the silicon wafer to obtain a third water-washed silicon wafer;

[0096] (10) Drying: the third water-washed silicon wafer is dried to obtain the silicon wafer for solar cells; the pyramid-shaped textured surface structure of the silicon wafer for solar cells in a straight state and a curved state is shown in FIGS. 1 and 2. Figure 2

[0097] ​Example 4

[0098] The silicon wafer for solar cell of Example 4 was prepared according to the texturing method of Example 3, except that:

[0099] Step (3) in Example 4 was: using the first texturing solution to texturize the silicon wafer after the first water washing, the temperature was controlled at 75℃, the time was controlled at 200s, and the first target silicon wafer was obtained; the first texturing solution included the first alkali solution and the first texturing additive, the mass concentration of the first texturing additive in the first texturing solution was 0.3%; the first alkali solution was sodium hydroxide solution, the mass concentration of sodium hydroxide in the first texturing solution was 2%; the type of the first texturing additive was Shichuang TS50.

[0100] Step (5) in Example 4 was: using the second texturing solution to texturize the silicon wafer after the first alkali washing, the temperature was controlled at 87℃, the time was controlled at 200s, and the twice-textured silicon wafer was obtained; the second texturing solution included the second alkali solution and the second texturing additive, the mass concentration of the second texturing additive in the second texturing solution was 0.1%; the second alkali solution was potassium hydroxide solution, the mass concentration of potassium hydroxide in the second texturing solution was 0.7%; the type of the second texturing additive was Shichuang TS52.

[0101] Example 5

[0102] The silicon wafer for solar cell of Example 5 was prepared according to the texturing method of Example 3, except that:

[0103] Step (3) in Example 5 was: using the first texturing solution to texturize the silicon wafer after the first water washing, the temperature was controlled at 75℃, the time was controlled at 200s, and the first target silicon wafer was obtained; the first texturing solution included the first alkali solution and the first texturing additive, the mass concentration of the first texturing additive in the first texturing solution was 1.5%; the first alkali solution was sodium hydroxide solution, the mass concentration of sodium hydroxide in the first texturing solution was 2%; the type of the first texturing additive was Shichuang TS50.

[0104] Step (5) in Example 5 was: using the second texturing solution to texturize the silicon wafer after the first alkali washing, the temperature was controlled at 87℃, the time was controlled at 200s, and the twice-textured silicon wafer was obtained; the second texturing solution included the second alkali solution and the second texturing additive, the mass concentration of the second texturing additive in the second texturing solution was 0.9%; the second alkali solution was potassium hydroxide solution, the mass concentration of potassium hydroxide in the second texturing solution was 0.7%; the type of the second texturing additive was Shichuang TS52.

[0105] Example 6

[0106] The silicon wafer for solar cell of Example 6 was prepared by referring to the texturing method of Example 3, except that:

[0107] Step (3) in Example 6 was: using the first texturing solution to texturize the once water-washed silicon wafer, the first texturing was controlled at 75℃, and the time was controlled at 200s, to obtain the first target silicon wafer; the first texturing solution included the first alkali solution and the first texturing additive, the mass concentration of the first texturing additive in the first texturing solution was 0.8%; the first alkali solution was sodium hydroxide solution, the mass concentration of sodium hydroxide in the first texturing solution was 5%; the model of the first texturing additive was Shichuang TS50.

[0108] Step (5) in Example 6 was: using the second texturing solution to texturize the once alkali-washed silicon wafer, the second texturing was controlled at 87℃, and the time was controlled at 200s, to obtain the twice texturized silicon wafer; the second texturing solution included the second alkali solution and the second texturing additive, the mass concentration of the second texturing additive in the second texturing solution was 0.3%; the second alkali solution was potassium hydroxide solution, the mass concentration of potassium hydroxide in the second texturing solution was 3%; the model of the second texturing additive was Shichuang TS52.

[0109] Example 7

[0110] The silicon wafer for solar cell of Example 7 was prepared by referring to the texturing method of Example 3, except that:

[0111] Step (3) in Example 7 was: using the first texturing solution to texturize the once water-washed silicon wafer, the first texturing was controlled at 75℃, and the time was controlled at 200s, to obtain the first target silicon wafer; the first texturing solution included the first alkali solution and the first texturing additive, the mass concentration of the first texturing additive in the first texturing solution was 0.8%; the first alkali solution was sodium hydroxide solution, the mass concentration of sodium hydroxide in the first texturing solution was 0.3%; the model of the first texturing additive was Shichuang TS50.

[0112] Step (5) in Example 7 was: using the second texturing solution to texturize the once alkali-washed silicon wafer, the second texturing was controlled at 87℃, and the time was controlled at 200s, to obtain the twice texturized silicon wafer; the second texturing solution included the second alkali solution and the second texturing additive, the mass concentration of the second texturing additive in the second texturing solution was 0.3%; the second alkali solution was potassium hydroxide solution, the mass concentration of potassium hydroxide in the second texturing solution was 2%; the model of the second texturing additive was Shichuang TS52.

[0113] Example 8

[0114] The silicon wafer for solar cell of Example 8 was prepared by referring to the texturing method of Example 3, except that:

[0115] Step (3) in Example 8 is: using the first texturing solution to perform first texturing on the once water-washed silicon wafer, the first texturing is controlled at 70℃, the time is controlled at 200s, to obtain the first target silicon wafer; the first texturing solution comprises a first alkali solution and a first texturing additive, the mass concentration of the first texturing additive in the first texturing solution is 0.8%; the first alkali solution is sodium hydroxide solution, the mass concentration of sodium hydroxide in the first texturing solution is 2%; the model of the first texturing additive is Shichuang TS50.

[0116] Step (5) in Example 8 is: using the second texturing solution to perform second texturing on the once alkali-washed silicon wafer, the second texturing is controlled at 75℃, the time is controlled at 200s, to obtain the twice-textured silicon wafer; the second texturing solution comprises a second alkali solution and a second texturing additive, the mass concentration of the second texturing additive in the second texturing solution is 0.3%; the second alkali solution is potassium hydroxide solution, the mass concentration of potassium hydroxide in the second texturing solution is 0.7%; the model of the second texturing additive is Shichuang TS52.

[0117] Example 9

[0118] The silicon wafer for solar cells in Example 9 is prepared by referring to the texturing method of Example 3, with the difference being that:

[0119] Step (3) in Example 9 is: using the first texturing solution to perform first texturing on the once water-washed silicon wafer, the first texturing is controlled at 75℃, the time is controlled at 200s, to obtain the first target silicon wafer; the first texturing solution comprises a first alkali solution and a first texturing additive, the mass concentration of the first texturing additive in the first texturing solution is 0.8%; the first alkali solution is sodium hydroxide solution, the mass concentration of sodium hydroxide in the first texturing solution is 2%; the model of the first texturing additive is Shichuang TS50.

[0120] Step (5) in Example 9 is: using the second texturing solution to perform second texturing on the once alkali-washed silicon wafer, the second texturing is controlled at 80℃, the time is controlled at 200s, to obtain the twice-textured silicon wafer; the second texturing solution comprises a second alkali solution and a second texturing additive, the mass concentration of the second texturing additive in the second texturing solution is 0.3%; the second alkali solution is potassium hydroxide solution, the mass concentration of potassium hydroxide in the second texturing solution is 0.7%; the model of the second texturing additive is Shichuang TS52.

[0121] Example 10

[0122] The silicon wafer for solar cells in Example 10 is prepared by referring to the texturing method of Example 3, with the difference being that:

[0123] Step (3) in Embodiment 10 is: using the first texturing solution to texturize the once-washed silicon wafer, and the first texturing is controlled at 75℃ and for 200s to obtain the first target silicon wafer; the first texturing solution comprises a first alkali solution and a first texturing additive, and the mass concentration of the first texturing additive in the first texturing solution is 0.8%; the first alkali solution is a sodium hydroxide solution, and the mass concentration of sodium hydroxide in the first texturing solution is 2%; the first texturing additive comprises, by mass percentage: sodium hydroxide 0.5%, isopropyl alcohol 5%, additive 0.5%, and the balance is water, totaling 100%; the additive comprises, by mass percentage: sodium gluconate 0.06%, polyoxyethylene ether 3000ppb, sodium citrate 0.2%, propylene glycol 0.7%, sodium silicate 0.9%, sodium carbonate 0.6%, and the balance is water, totaling 100%.

[0124] Step (5) in Embodiment 10 is: using the second texturing solution to texturize the once-washed silicon wafer, and the second texturing is controlled at 87℃ and for 200s to obtain the twice-textured silicon wafer; the second texturing solution comprises a second alkali solution and a second texturing additive, and the mass concentration of the second texturing additive in the second texturing solution is 0.3%; the second alkali solution is a potassium hydroxide solution, and the mass concentration of potassium hydroxide in the second texturing solution is 0.7%; the second texturing additive comprises, by mass percentage: sodium hydroxide 0.5%, isopropyl alcohol 3%, additive 0.7%, and the balance is water, totaling 100%; the additive comprises, by mass percentage: sodium gluconate 0.06%, polyoxyethylene ether 3000ppb, sodium citrate 0.2%, propylene glycol 0.7%, sodium silicate 0.9%, sodium carbonate 0.6%, and the balance is water, totaling 100%.

[0125] Embodiment 11

[0126] The silicon wafer for solar cells in Embodiment 11 is prepared by referring to the texturing method in Embodiment 3, except that:

[0127] Step (3) in Example 11 is: using the first texturing solution to perform the first texturing on the once water-washed silicon wafer, the temperature is controlled at 75℃, the time is controlled at 200s, and a first target silicon wafer is obtained; the first texturing solution comprises a first alkali solution and a first texturing additive, and the mass concentration of the first texturing additive in the first texturing solution is 0.8%; the first alkali solution is a sodium hydroxide solution, and the mass concentration of sodium hydroxide in the first texturing solution is 2%; the first texturing additive comprises, in percentage by mass: 0.5% of sodium hydroxide, 7% of isopropyl alcohol, 0.5% of an additive, and the balance being water, totaling 100%; the additive comprises, in percentage by mass: 0.06% of sodium gluconate, 3000ppb of polyoxyethylene ether, 0.2% of sodium citrate, 0.7% of propylene glycol, 0.9% of sodium silicate, 0.6% of sodium carbonate, and the balance being water, totaling 100%.

[0128] Step (5) in Example 11 is: using the second texturing solution to perform the second texturing on the once alkali-washed silicon wafer, the temperature is controlled at 87℃, the time is controlled at 200s, and a twice-textured silicon wafer is obtained; the second texturing solution comprises a second alkali solution and a second texturing additive, and the mass concentration of the second texturing additive in the second texturing solution is 0.3%; the second alkali solution is a potassium hydroxide solution, and the mass concentration of potassium hydroxide in the second texturing solution is 0.7%; the second texturing additive comprises, in percentage by mass: 0.5% of sodium hydroxide, 2% of isopropyl alcohol, 2% of an additive, and the balance being water, totaling 100%; the additive comprises, in percentage by mass: 0.06% of sodium gluconate, 3000ppb of polyoxyethylene ether, 0.2% of sodium citrate, 0.7% of propylene glycol, 0.9% of sodium silicate, 0.6% of sodium carbonate, and the balance being water, totaling 100%.

[0129] Comparative Example 1

[0130] A texturing method for a silicon wafer for a solar cell comprises:

[0131] (1) Pre-cleaning: a single crystal silicon wafer with a thickness of 150μm is placed into a mixed solution of NaOH+H2O2 for pre-cleaning, a rough polishing is performed to remove a damage layer and impurities on the surface of the silicon wafer, and a pre-cleaned silicon wafer is obtained;

[0132] (2) First water washing: the pre-cleaned silicon wafer is cleaned with pure water, and a once water-washed silicon wafer is obtained;

[0133] (3) Texturing: a texturing solution is used to perform the first texturing on the once water-washed silicon wafer, the temperature is controlled at 80℃, the time is controlled at 400s, and a first target silicon wafer is obtained; the texturing solution comprises an alkali solution and a texturing additive, and the mass concentration of the texturing additive in the texturing solution is 0.8%; the alkali solution is a sodium hydroxide solution, and the mass concentration of sodium hydroxide in the first texturing solution is 1.5%; the texturing additive is a type of Shichuang TS50;

[0134] (4) Alkaline cleaning: the first target silicon wafer is put into a mixed solution of NaOH + H2O2 for alkaline cleaning to remove impurities on the surface of the silicon wafer, and an alkaline cleaned silicon wafer is obtained;

[0135] (5) Second water cleaning: the surface of the alkaline cleaned silicon wafer is cleaned with pure water to remove the alkaline solution, and a second water cleaned silicon wafer is obtained;

[0136] (6) Acid cleaning: the second water cleaned silicon wafer is subjected to acid cleaning with hydrochloric acid + hydrofluoric acid to remove impurities on the surface of the silicon wafer, and an acid cleaned silicon wafer is obtained;

[0137] (7) Third water cleaning: the surface of the acid cleaned silicon wafer is cleaned with pure water to remove the acid solution, and a third water cleaned silicon wafer is obtained;

[0138] (8) Slow pulling: the third water cleaned silicon wafer is subjected to slow pulling with pure water to remove the acid solution and pre-dehydrate the silicon wafer, and a slow pulled silicon wafer is obtained;

[0139] (9) Drying: the third water cleaned silicon wafer is dried in a nitrogen atmosphere to obtain the silicon wafer for solar cells; the pyramid textured structure of the silicon wafer for solar cells in a straight state and a curved state is shown in FIG. 1. Figure 1

[0140] The silicon wafers for solar cells prepared in the above examples and comparative examples are tested, and the test results are shown in Table 1.

[0141] Table 1 (with reference to Comparative Example 1, the silicon wafer fragment rate reduction effect and the silicon wafer reflectivity reduction effect data of Examples 1-11 are obtained)

[0142]

[0143] The data in the above table show that, taking Example 1 as an example, the silicon wafer fragment rate in Example 1 is reduced by 0.55% compared with Comparative Example 1; the silicon wafer reflectivity in Example 1 is reduced by 0.21% compared with Comparative Example 1. Referring to the test data of Examples 1-11, in the technical scheme of the present application, the silicon wafer is sequentially subjected to first texturing and second texturing, and the process parameters of the first texturing and the second texturing are controlled, which can improve the interaction between the texturing solution and the silicon wafer, improve the uniformity of the pyramid textured structure, and also modify the pyramid textured structure to make the lines of the pyramid textured structure more rounded, form a pyramid textured structure with curved surface structure on the side surface, and the curved pyramid textured structure is not easy to break when the silicon wafer is bent, thereby reducing the silicon wafer fragment rate and improving the long-term stability and reliability of the solar cell. It can further reduce light loss and improve light absorption effect.

[0144] ​Referring to the detection data of the above-mentioned Examples 1-3, Examples 4-5, it can be seen that optimizing the concentration of the texturing additive in the texturing solution can improve the interaction between the texturing solution and the silicon wafer, form a higher reaction rate difference between the top position and the bottom position of the pyramid, help to modify the pyramid texture structure, make the lines of the pyramid texture structure more rounded, form a pyramid texture structure with curved surface on the side surface, and the curved pyramid texture structure is not easy to break when the silicon wafer is bent, which can further reduce the silicon wafer fragment rate, and further improve the long-term stability and reliability of the solar cell. It can also further reduce the light loss, and further improve the light absorption effect.

[0145] Referring to the detection data of the above-mentioned Examples 3, Examples 6-7, it can be seen that optimizing the concentration of the alkali in the texturing solution can improve the interaction between the texturing solution and the silicon wafer, form a higher reaction rate difference between the top position and the bottom position of the pyramid, help to modify the pyramid texture structure, make the lines of the pyramid texture structure more rounded, form a pyramid texture structure with curved surface on the side surface, and the curved pyramid texture structure is not easy to break when the silicon wafer is bent, which can further reduce the silicon wafer fragment rate, and further improve the long-term stability and reliability of the solar cell. It can also further reduce the light loss, and further improve the light absorption effect.

[0146] Referring to the detection data of the above-mentioned Examples 3, Examples 8-9, it can be seen that optimizing the texturing temperature can improve the interaction between the texturing solution and the silicon wafer, form a higher reaction rate difference between the top position and the bottom position of the pyramid, help to modify the pyramid texture structure, make the lines of the pyramid texture structure more rounded, form a pyramid texture structure with curved surface on the side surface, and the curved pyramid texture structure is not easy to break when the silicon wafer is bent, which can further reduce the silicon wafer fragment rate, and further improve the long-term stability and reliability of the solar cell. It can also further reduce the light loss, and further improve the light absorption effect.

[0147] Referring to the detection data of the above-mentioned Examples 3, Examples 10-11, it can be seen that optimizing the content of isopropyl alcohol and the additive in the texturing additive can improve the interaction between the texturing solution and the silicon wafer, form a higher reaction rate difference between the top position and the bottom position of the pyramid, help to modify the pyramid texture structure, make the lines of the pyramid texture structure more rounded, form a pyramid texture structure with curved surface on the side surface, and the curved pyramid texture structure is not easy to break when the silicon wafer is bent, which can further reduce the silicon wafer fragment rate, and further improve the long-term stability and reliability of the solar cell. It can also further reduce the light loss, and further improve the light absorption effect.

[0148] To sum up, in the technical scheme of the application, the silicon wafer is sequentially subjected to first texturing and second texturing, and the process parameters of the first texturing and the second texturing are controlled, so that the interaction between the texturing solution and the silicon wafer is improved, the uniformity of the pyramid-shaped textured structure is improved, the pyramid-shaped textured structure is modified, the lines of the pyramid-shaped textured structure are smoother, the pyramid-shaped textured structure with a curved surface structure is formed, the curved pyramid-shaped textured structure is not easy to break when the silicon wafer is bent, the silicon wafer breakage rate is reduced, and the long-term stability and reliability of the solar cell are improved. The light loss is further reduced, and the light absorption effect is improved.

[0149] In addition, the silicon wafer is textured according to the method in Comparative Example 1. In order to ensure the quality of the silicon wafer, the drying must be carried out in a nitrogen atmosphere, which increases the cost of drying the silicon wafer. According to the method of the application, the silicon wafer is textured, and the final drying step can be carried out in an air atmosphere. Compared with the above, the drying cost is lower. Therefore, according to the texturing process of the application, the subsequent drying step is facilitated.

[0150] The application can provide a silicon wafer for a solar cell, which is prepared by the above method. The silicon wafer for a solar cell prepared by the above method has the advantages of the above.

[0151] The application can provide a photoelectric device comprising the above-mentioned silicon wafer for a solar cell. The silicon wafer for a solar cell has the advantages of the above. The photoelectric device comprises a crystalline silicon solar cell.

[0152] The application can provide a photovoltaic system comprising the above-mentioned photoelectric device (e.g., a crystalline silicon solar cell). The photovoltaic system has the advantages of the above-mentioned solar cell, which will not be described here. The application field of the photovoltaic system is wide, and is not limited to photovoltaic power stations, such as ground power stations, roof power stations, and water surface power stations, but also includes various devices and apparatuses that utilize solar energy to generate electricity, such as user solar power sources, solar street lamps, solar cars, and solar buildings. Of course, it can be understood that the application field of the photovoltaic system is not limited to this, that is, the photovoltaic system can be applied in all fields that need to use solar energy to generate electricity. For example, the photovoltaic system can include a photovoltaic array, a combiner box, and an inverter. The photovoltaic array can be an array combination of a plurality of photovoltaic components. For example, a plurality of photovoltaic components can form a plurality of photovoltaic arrays. The photovoltaic array is connected to the combiner box. The combiner box can combine the current generated by the photovoltaic array. The combined current flows through the inverter to convert it into alternating current required by the power grid, and then is connected to the power grid to realize solar power supply.

[0153] It should be noted that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like are merely intended to facilitate the description of the application and simplify the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the application. The orientation terms "inner" and "outer" refer to the inner and outer of the profile of each component itself. For example, if the device in the drawings is inverted, the device described as "above" or "above" other devices or structures will be positioned "below" or "below" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below" orientations. The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein are interpreted accordingly.

[0154] It should also be noted that the "one embodiment", "another embodiment", "embodiment" and the like mentioned in the present application refer to the specific features, structures or characteristics described in connection with the embodiment, which are included in at least one embodiment described generally in the present application. The same expression appearing in several places in the specification does not necessarily refer to the same embodiment. Further, when a specific feature, structure or characteristic is described in connection with any embodiment, it is claimed that the implementation of such feature, structure or characteristic in connection with other embodiments also falls within the scope of the present application.

[0155] In the above embodiments, the description of each embodiment has its own emphasis, and the parts not described in detail in a certain embodiment can be referred to the relevant description of other embodiments.

[0156] It should also be noted that the above is only the preferred embodiment of the present application, and does not limit the patent protection scope of the present application, and any equivalent structure or equivalent process transformation using the content of the present application specification and drawings, or direct or indirect application in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A method for texturing a silicon wafer for solar cells, characterized in that, The method comprises the following steps: carrying out first texturing on a silicon wafer by using a first texturing solution to obtain a first target silicon wafer; the first texturing solution comprises a first alkali solution and a first texturing additive; carrying out second texturing on the first target silicon wafer by using a second texturing solution to form a pyramid texturing structure with curved surface structure on the side surface, thereby obtaining the silicon wafer for solar cells; the second texturing solution comprises a second alkali solution and a second texturing additive; wherein the mass concentration of alkali in the first texturing solution is higher than that in the second texturing solution; the mass concentration of the first texturing additive in the first texturing solution is higher than that of the second texturing additive in the second texturing solution; and the temperature of the first texturing is lower than that of the second texturing.

2. The method of claim 1, wherein, in terms of mass percentage: the mass concentration of the first texturing additive in the first texturing solution is 0.5-1.5%; and / or the mass concentration of the second texturing additive in the second texturing solution is 0.1-0.5%.

3. The method of claim 1, wherein, in terms of mass percentage: the mass concentration of alkali in the first texturing solution is 0.5-5%; and / or the mass concentration of alkali in the second texturing solution is 0.2-1.5%.

4. The method according to claim 1, characterized in that: the sum of the time of the first texturing and the time of the second texturing is 400-500s; wherein the temperature of the first texturing is controlled at 70-85℃, and the time of the first texturing is controlled at 60-400s; and / or the temperature of the second texturing is controlled at 85-90℃, and the time of the second texturing is controlled at 10-500s.

5. The method of claim 1, wherein, the first texturing additive comprises isopropyl alcohol and an additive; and the second texturing additive comprises isopropyl alcohol and an additive; wherein the mass concentration of isopropyl alcohol in the first texturing additive is denoted as W1, and the mass concentration of the additive in the first texturing additive is denoted as W2; the mass concentration of isopropyl alcohol in the second texturing additive is denoted as W1', and the mass concentration of the additive in the second texturing additive is denoted as W2'; W1 and W1' satisfy the relationship W1>W1'; and W2 and W2' satisfy the relationship W2 6. The method of claim 1, wherein, further comprising: carrying out alkali washing on the first target silicon wafer after the first texturing and before the second texturing; and / or carrying out alkali washing on the first target silicon wafer after the second texturing. prepared by the method according to any one of claims 1-6.

7. A silicon wafer for a solar cell, characterized by, the silicon wafer for solar cells according to claim 7.

8. An optoelectronic device, characterized in that the optoelectronic device comprises a crystalline silicon solar cell.

9. The optoelectronic device of claim 8, wherein, the optoelectronic device according to claim 8 or 9.

10. A photovoltaic system characterized by, ​

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