Method for preparing silicon dioxide nanoparticles and method for preparing heterojunction solar cell

Abstract

The present invention provides a method for preparing silicon dioxide nanoparticles and a method for preparing a heterojunction solar cell. The method for preparing silicon dioxide nanoparticles involves using an organic amine as a catalyst and a template agent and using tetraethyl orthosilicate as a precursor, adding a silicon source precursor to a target solution, and then performing temperature control to evaporate the organic amine solvent ethanol, making it difficult for the organic amine catalyst to come into contact with the reactant, thus greatly inhibiting the hydrolysis of tetraethyl orthosilicate, so that a two-dimensional network silicon dioxide nanostructure can be obtained. When a liquid containing the two-dimensional network silicon dioxide nanostructure is applied to a heterojunction solar cell, significant hydrophobicity and anti-reflection performance can be shown. In addition, the method for preparing silicon dioxide nanoparticles has a short reaction time and a simple preparation process and greatly saves the preparation cost.

Description

Preparation method of silicon dioxide nanoparticles and heterojunction solar cells Technical Field

[0001] The present invention relates to the technical field of solar cells, and more particularly to a method for preparing silicon dioxide nanoparticles and heterojunction solar cells. Background Art

[0002] Because the contact area between the surface of the superhydrophobic structure and water is limited, the chemical reaction and chemical bond combination with water are inhibited, thus having excellent interfacial properties such as anti-pollution, self-cleaning, anti-snow and ice, and anti-corrosion. It is expected to be used in windshields, display screens, solar cell covers, architectural glass curtain walls and other fields.

[0003] Silicon heterojunction solar cells have an ITO conductive glass on the surface. This ITO conductive glass is susceptible to water absorption and failure, and its high reflectivity due to its limited refractive index. Therefore, silicon heterojunction solar cells require a structure that combines anti-reflection and self-cleaning properties. Silicon dioxide nanomaterials have attracted much attention due to their low refractive index, low cost, and ease of preparation and modification. Technical issues

[0004] Many researchers, both domestically and internationally, have conducted a series of studies on the application of silica hydrophobic materials. For example, a sol-gel method has been used to prepare chain- and granular silica aggregates, using silica chains to anchor silica particles to achieve a durable superhydrophobic coating on a glass substrate. Another approach has been to use a sol-gel impregnation method, using tetraethyl orthosilicate and trimethylethoxysilane as co-precursors, and then base-catalyzing the hydrolysis to produce a methyl-containing nano-silica sol, to prepare a coating with high transmittance and excellent superhydrophobicity.

[0005] However, these methods currently have certain limitations, such as cumbersome operations, long reaction times, difficulty in controlling product size, and difficulty in large-scale preparation, which makes the preparation cost very high and difficult to scale up production. Technical Solutions

[0006] In view of this, in order to solve the above problems, the present invention provides a method for preparing silicon dioxide nanoparticles and heterojunction solar cells, and the technical solution is as follows:

[0007] A method for preparing silicon dioxide nanoparticles, comprising:

[0008] Dispersing tetraethyl orthosilicate in anhydrous ethanol to obtain a silicon source precursor;

[0009] dissolving an organic amine catalyst in a mixed solution of water and ethanol, and stirring at a first speed to obtain a target solution;

[0010] adding the silicon source precursor to the target solution and stirring at a second speed, and performing temperature control during the stirring process to react and obtain silicon dioxide nanoparticles;

[0011] The silica nanoparticles are alternately centrifuged and washed at a third speed based on ethanol and water, and dried to obtain a two-dimensional network silica nanostructure; wherein the two-dimensional silica nanoparticles in the two-dimensional network silica nanostructure are composed of long circular chains, and the network gaps are filled with air.

[0012] Preferably, in the above-mentioned method for preparing silicon dioxide nanoparticles, the volume of tetraethyl orthosilicate ranges from 1 ml to 6 ml;

[0013] The volume of the anhydrous ethanol ranges from 8 ml to 48 ml.

[0014] Preferably, in the above-mentioned method for preparing silicon dioxide nanoparticles, the weight range of the organic amine catalyst is 0.1g-1.0g;

[0015] The volume of water in the mixed solution ranges from 35 ml to 45 ml, and the volume of ethanol in the mixed solution ranges from 15 ml to 25 ml.

[0016] Preferably, in the above-mentioned method for preparing silicon dioxide nanoparticles, the organic amine catalyst is a dodecylamine catalyst or a hexadecylamine catalyst.

[0017] Preferably, in the above-mentioned method for preparing silicon dioxide nanoparticles, the first speed ranges from 800 rpm to 1200 rpm, and the duration of stirring at the first speed ranges from 1 min to 3 min.

[0018] Preferably, in the above-mentioned method for preparing silicon dioxide nanoparticles, the second speed ranges from 250 rpm to 350 rpm, and the duration of stirring at the second speed ranges from 3 h to 4.5 h.

[0019] Preferably, in the above-mentioned method for preparing silica nanoparticles, the third speed ranges from 7000 rpm to 9000 rpm, and the duration of alternating centrifugal washing at the third speed ranges from 4 min to 6 min;

[0020] The drying temperature of the drying process is in the range of 75° C. to 85° C., and the drying duration of the drying process is in the range of 8 h to 12 h.

[0021] Preferably, in the above-mentioned method for preparing silicon dioxide nanoparticles, the temperature range of the temperature control treatment is 45° C.-65° C., and the duration range of the temperature control treatment is 2 h-5 h.

[0022] The present application also provides a method for preparing a heterojunction solar cell, the method comprising:

[0023] Prepare a dispersion of a two-dimensional network silica nanostructure, wherein the two-dimensional network silica nanostructure is the two-dimensional network silica nanostructure prepared by any one of the above methods;

[0024] The dispersion of the two-dimensional network silicon dioxide nanostructure is dispersed on the surface of a heterojunction solar cell and dried to obtain a heterojunction solar cell having a film layer of the two-dimensional network silicon dioxide nanostructure.

[0025] Preferably, in the above-mentioned method for preparing heterojunction solar cells, the dispersion liquid for configuring the two-dimensional network silica nanostructure comprises:

[0026] dispersing the two-dimensional network silica nanostructure in a mixed solution and performing ultrasonic treatment;

[0027] The volume of the mixed solution ranges from 8 ml to 12 ml, the mixed solution is a mixed solution of chloroform and ethanol, and the volume ratio of chloroform to ethanol in the mixed solution ranges from 4:1 to 5:1. Beneficial effects

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] The present invention provides a method for preparing silica nanoparticles, comprising: dispersing tetraethyl orthosilicate in anhydrous ethanol to obtain a silicon source precursor; dissolving an organic amine catalyst in a mixed solution of water and ethanol and stirring at a first speed to obtain a target solution; adding the silicon source precursor to the target solution and stirring at a second speed, while controlling the temperature during the stirring process, to react and obtain silica nanoparticles; washing the silica nanoparticles by alternating centrifugation with ethanol and water at a third speed, and drying to obtain a two-dimensional network silica nanostructure; wherein the two-dimensional silica nanoparticles in the two-dimensional network silica nanostructure are composed of long circular chains, and the network gaps are filled with air. The method uses an organic amine as a catalyst and template and tetraethyl orthosilicate as a precursor. After the silicon source precursor is added to the target solution, the temperature is controlled to evaporate the organic amine solvent ethanol, making it difficult for the organic amine catalyst to contact the reactants, thereby greatly inhibiting the hydrolysis of the tetraethyl orthosilicate, thereby obtaining a two-dimensional network silica nanostructure. Applying a liquid containing the two-dimensional mesh-like silica nanostructure to a heterojunction solar cell exhibits significant hydrophobicity and anti-reflection properties. Furthermore, the preparation method for the silica nanoparticles has a short reaction time and a simple preparation process, significantly reducing preparation costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0031] FIG1 is a schematic flow chart of a method for preparing silicon dioxide nanoparticles provided in an embodiment of the present invention;

[0032] FIG2 is a schematic diagram of a water contact angle test on the surface of silicon dioxide nanoparticles provided in an embodiment of the present invention;

[0033] FIG3 is a schematic diagram of light transmittance of a glass having a two-dimensional network of silica nanostructures provided by an embodiment of the present invention;

[0034] FIG4 is a transmission electron microscope diagram of a silicon dioxide nanoparticle provided in an embodiment of the present invention;

[0035] FIG5 is a schematic flow chart of a method for preparing a heterojunction solar cell provided in an embodiment of the present invention. Best Mode for Carrying Out the Invention

[0036] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0037] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0038] Referring to FIG1 , FIG1 is a schematic flow chart of a method for preparing silicon dioxide nanoparticles provided in an embodiment of the present invention. The method for preparing silicon dioxide nanoparticles provided in an embodiment of the present invention comprises:

[0039] S101: Dispersing tetraethyl orthosilicate in anhydrous ethanol to obtain a silicon source precursor.

[0040] Specifically, in this step, tetraethyl orthosilicate can be ultrasonically dispersed in anhydrous ethanol to obtain a silicon source precursor, wherein the volume of the tetraethyl orthosilicate is in the range of 1 ml to 6 ml; and the volume of the anhydrous ethanol is in the range of 8 ml to 48 ml.

[0041] S102: dissolving an organic amine catalyst in a mixed solution of water and ethanol, and stirring the mixed solution at a first rotation speed to obtain a target solution.

[0042] Specifically, in this step, stirring is performed at a first speed to make it as uniform as possible to obtain a target solution, the weight range of the organic amine catalyst is 0.1g-1.0g; the volume range of water in the mixed solution is 35ml-45ml, and the volume range of ethanol in the mixed solution is 15ml-25ml.

[0043] The organic amine catalyst includes but is not limited to a dodecylamine catalyst or a hexadecylamine catalyst.

[0044] The first speed ranges from 800 rpm to 1200 rpm, and the duration of stirring at the first speed ranges from 1 min to 3 min.

[0045] S103: adding the silicon source precursor to the target solution and stirring at a second rotation speed, and performing temperature control during the stirring process to react and obtain silicon dioxide nanoparticles.

[0046] Specifically, in this step, the second speed ranges from 250 rpm to 350 rpm, and the duration of stirring at the second speed ranges from 3 h to 4.5 h.

[0047] The temperature range of the temperature control treatment is 45° C.-65° C., and the duration range of the temperature control treatment is 2 h-5 h.

[0048] S104: Washing the silica nanoparticles by alternating centrifugation with ethanol and water at a third speed, and obtaining a two-dimensional network silica nanostructure after drying; wherein the two-dimensional silica nanoparticles in the two-dimensional network silica nanostructure are composed of long circular chains, and the network gaps are filled with air.

[0049] Specifically, in this step, the speed range of the third speed is 7000rpm-9000rpm, and the duration range of alternating centrifugal washing at the third speed is 4min-6min; the drying temperature range of the drying treatment is 75℃-85℃, and the drying duration range of the drying treatment is 8h-12h.

[0050] Specifically, in the present embodiment, the method for preparing silica nanoparticles uses an organic amine as a catalyst and template, and tetraethyl orthosilicate as a precursor. After the silicon source precursor is added to the target solution, the temperature is controlled to evaporate the organic amine's solvent, ethanol, making it difficult for the organic amine catalyst to come into contact with the reactants. This significantly inhibits the hydrolysis of the tetraethyl orthosilicate, resulting in a two-dimensional network of silica nanostructures. When a liquid containing this two-dimensional network of silica nanostructures is applied to a heterojunction solar cell, it exhibits significant hydrophobicity and anti-reflection properties.

[0051] Specifically, this method for preparing silica nanoparticles utilizes an organic amine-water-alcohol system to produce silica nanoparticles with a large specific surface area. A two-dimensional mesh silica nanostructure is obtained through a one-step synthesis process, resulting in a short reaction time and a simple preparation process, significantly reducing production costs. Because the silica nanoparticles are coated with a large amount of organic amine on their surface, they possess strong hydrophobicity. Furthermore, due to the air filling, the silica nanoparticles have an equivalent refractive index lower than that of the transparent electrode on a heterojunction solar cell. Applying a liquid containing this two-dimensional mesh silica nanostructure to the surface of the heterojunction solar cell creates a surface hydrophobic structure, enhancing the anti-reflection effect of the heterojunction solar cell. This surface hydrophobic structure requires no modification and exhibits both self-cleaning and anti-reflection properties. Modes for Carrying Out the Invention

[0052] The technical solution of the present invention is further illustrated below with seven specific embodiments.

[0053] Specific embodiment 1

[0054] Dissolve 3ml of tetraethyl orthosilicate in 35ml of anhydrous ethanol and sonicate for 10 minutes to thoroughly mix. This is used as the silicon source precursor reaction solution. Weigh 0.4g of dodecylamine as an organic amine catalyst and place it in a reaction vessel. Add 20ml of anhydrous ethanol and 35ml of deionized water, respectively. Stir at 1000rpm. After approximately 2 minutes, add the silicon source precursor reaction solution and mix thoroughly. Then, reduce the stirring speed to 300rpm and heat in a 45°C water bath for 4 hours. Wash the solid product six times by alternating centrifugation with ethanol and water at 8000rpm for 5 minutes, then dry it in a forced air drying oven at 80°C for 10 hours.

[0055] Among them, the reaction at 45°C obtains a two-dimensional network silica nanostructure, wherein the two-dimensional silica nanoparticles in the two-dimensional network silica nanostructure are composed of long circular chains, and the network gaps are filled with air. This is the key to the two-dimensional network silica nanostructure for reducing the refractive index on the glass surface. When the reaction temperature increases, the probability of contact between the organic amine and the reactant decreases, and the growth of silica nucleation is restricted. The slowdown of its surface growth rate is a key condition for obtaining a two-dimensional network silica nanostructure. Referring to Figure 2, Figure 2 is a schematic diagram of a water contact angle test on the surface of a silica nanoparticle provided in an embodiment of the present invention. As shown in Figure 2, it exhibits obvious hydrophobicity, and its use on the surface of heterojunction solar cells can obviously achieve the purpose of self-cleaning. Referring to Figure 3, Figure 3 is a schematic diagram of the light transmittance of a glass having a two-dimensional network silica nanostructure provided by an embodiment of the present invention. The transmittance is increased by reducing the refractive index. The result of the two-dimensional network silica nanostructure on the glass surface is shown in Figure 3. The net increase in transmittance is about 1.2%. Obviously, this is a low-cost, environmentally friendly and efficient preferred material for heterojunction battery anti-reflection and glass coating.

[0056] It should be noted that the blank glass in FIG3 refers to glass without a two-dimensional network silica nanostructure, and the coated glass refers to glass with a two-dimensional network silica nanostructure.

[0057] Specific embodiment 2

[0058] Dissolve 3ml of tetraethyl orthosilicate in 35ml of anhydrous ethanol and sonicate for 10 minutes to thoroughly mix. This is used as the silicon source precursor reaction solution. Weigh 0.4g of dodecylamine as an organic amine catalyst and place it in a reaction vessel. Add 20ml of anhydrous ethanol and 35ml of deionized water, respectively. Stir at 1000rpm. After approximately 2 minutes, add the silicon source precursor reaction solution and mix thoroughly. Then, reduce the stirring speed to 300rpm and heat in a 45°C water bath for 4 hours. Wash the solid product six times by alternating centrifugation with ethanol and water at 8000rpm for 5 minutes, then dry it in a forced air drying oven at 80°C for 10 hours.

[0059] Refer to Figure 4, which is a transmission electron microscope diagram of a silicon dioxide nanoparticle provided by an embodiment of the present invention, that is, Figure 4 shows a transmission electron microscope diagram of a two-dimensional network silicon dioxide nanostructure obtained by reaction under heating in a 45°C water bath.

[0060] Specific embodiment three

[0061] Dissolve 3ml of tetraethyl orthosilicate in 35ml of anhydrous ethanol and sonicate for 10 minutes to thoroughly mix. This solution is then used as the silicon source precursor reaction solution. 0.4g of dodecylamine, as an organic amine catalyst, is weighed and placed in a reaction vessel. 20ml of anhydrous ethanol and 35ml of deionized water are then added, followed by stirring at 1000rpm. After approximately 2 minutes, the silicon source precursor reaction solution is added and thoroughly mixed. The stirring speed is then reduced to 300rpm, and the mixture is heated in a 50°C water bath for 4 hours. The solid product is washed six times by alternating centrifugation with ethanol and water at 8000rpm for 5 minutes, and then dried in a forced air drying oven at 80°C for 10 hours. The resulting two-dimensional network silica nanostructure contains dispersed spherical silica particles.

[0062] Compared with the first specific embodiment, it can be seen that high temperature will inhibit the activity of silicon source hydrolysis, thereby slowing down the rate of silica spheroidization. The state before silica spheroidization is the target product nano-network structure in the embodiment of the present invention, that is, a two-dimensional network silica nanostructure.

[0063] Specific embodiment 4

[0064] Dissolve 3ml of tetraethyl orthosilicate in 35ml of anhydrous ethanol and sonicate for 10 minutes to thoroughly mix. This is used as the silicon source precursor reaction solution. Weigh 0.4g of hexadecylamine as an organic amine catalyst and place it in a reaction vessel. Add 20ml of anhydrous ethanol and 35ml of deionized water, followed by stirring at 1000rpm. After approximately 2 minutes, add the silicon source precursor reaction solution and mix thoroughly. Then, reduce the stirring speed to 300rpm and heat in a 45°C water bath for 4 hours. Wash the solid product six times by alternating centrifugation with ethanol and water at 8000rpm for 5 minutes, then dry it in a forced air drying oven at 80°C for 10 hours.

[0065] Compared with the first embodiment, it can be seen that changing the type of organic amine affects the reaction rate. This is because the longer the carbon chain of the organic amine catalyst, the weaker the catalytic effect, so the reaction time required to obtain the target product is prolonged; under the same conditions, the reaction temperature is higher.

[0066] Specific embodiment five

[0067] Dissolve 3ml of tetraethyl orthosilicate in 35ml of anhydrous ethanol and sonicate for 10 minutes to thoroughly mix. This is used as the silicon source precursor reaction solution. Weigh 0.4g of dodecylamine as an organic amine catalyst and place it in a reaction vessel. Add 20ml of anhydrous ethanol and 45ml of deionized water, followed by stirring at 1000rpm. After approximately 2 minutes, add the silicon source precursor reaction solution and mix thoroughly. Then, reduce the stirring speed to 300rpm and heat in a 45°C water bath for 4 hours. Wash the solid product six times by alternating centrifugation with ethanol and water at 8000rpm for 5 minutes, then dry it in a forced air drying oven at 80°C for 10 hours.

[0068] That is to say, by changing the amount of solvent within a certain range, similar results to those in the first embodiment can be obtained.

[0069] Specific embodiment six

[0070] Dissolve 2ml of tetraethyl orthosilicate in 35ml of anhydrous ethanol and sonicate for 10 minutes to thoroughly mix. This is used as the silicon source precursor reaction solution. Weigh 0.4g of dodecylamine as an organic amine catalyst and place it in a reaction vessel. Add 20ml of anhydrous ethanol and 35ml of deionized water, respectively. Stir at 1000rpm. After approximately 2 minutes, add the silicon source precursor reaction solution and mix thoroughly. Then, reduce the stirring speed to 300rpm and heat in a 45°C water bath for 4 hours. Wash the solid product six times with ethanol and water, alternating centrifugation at 8000rpm for 5 minutes, and dry it in a forced air drying oven at 80°C for 10 hours.

[0071] That is, by changing the amount of the silicon source reagent within a certain range, similar results to those in the first specific embodiment can be obtained.

[0072] Specific embodiment seven

[0073] Dissolve 3ml of tetraethyl orthosilicate in 35ml of anhydrous ethanol and sonicate for 10 minutes to thoroughly mix. This is used as the silicon source precursor reaction solution. Weigh 0.2g of dodecylamine as an organic amine catalyst and place it in a reaction vessel. Add 20ml of anhydrous ethanol and 35ml of deionized water, respectively. Stir at 1000rpm. After approximately 2 minutes, add the silicon source precursor reaction solution and mix thoroughly. Then, reduce the stirring speed to 300rpm and heat in a 45°C water bath for 4 hours. Wash the solid product six times by alternating centrifugation with ethanol and water at 8000rpm for 5 minutes, then dry it in a forced air drying oven at 80°C for 10 hours.

[0074] That is, by changing the amount of the organic amine catalyst within a certain range, similar results to those in the first specific embodiment can be obtained.

[0075] In summary, the two-dimensional network silicon dioxide nanostructures prepared in Specific Examples 2 to 7 were used on the surface of heterojunction solar cells, and similar results as those in Specific Example 1 were achieved in terms of enhanced hydrophobicity and light transmittance.

[0076] Based on the above embodiments of the present invention, another embodiment of the present invention further provides a method for preparing a heterojunction solar cell. Referring to FIG5 , FIG5 is a schematic flow chart of a method for preparing a heterojunction solar cell provided in an embodiment of the present invention. The method for preparing a heterojunction solar cell includes:

[0077] S201: preparing a dispersion of a two-dimensional network silica nanostructure, wherein the two-dimensional network silica nanostructure is the two-dimensional network silica nanostructure prepared in the above embodiment of the present invention.

[0078] Specifically, in this step, a dispersion of two-dimensional network silica nanostructures is prepared, including: dispersing the two-dimensional network silica nanostructures in a mixed solution and performing ultrasonic treatment; wherein the volume range of the mixed solution is 8ml-12ml, the mixed solution is a mixed solution of chloroform and ethanol, the volume ratio of chloroform to ethanol in the mixed solution ranges from 4:1 to 5:1, and the ultrasonic treatment time is 10min-30min.

[0079] S202: dispersing the dispersion of the two-dimensional network silica nanostructure on the surface of a heterojunction solar cell, and performing a drying process to obtain a heterojunction solar cell having a film layer of the two-dimensional network silica nanostructure.

[0080] Specifically, in this step, before dispersing the dispersion of the two-dimensional network silica nanostructure on the surface of the heterojunction solar cell, the heterojunction solar cell needs to be pretreated. The pretreatment includes ultrasonic treatment with acetone, ethanol and deionized water for 10 minutes respectively, and then dispersing the dispersion of the two-dimensional network silica nanostructure on the surface of the heterojunction solar cell, for example, dispersing it on the surface of the ITO conductive glass of the heterojunction solar cell; drying at a temperature environment of 45°C-55°C for 8min-12min, for example, drying at 50°C for 10min, to obtain a heterojunction solar cell carrying the two-dimensional network silica nanostructure. By conducting optical performance tests on it, it was found that the hydrophobicity and light transmittance of the heterojunction solar cell carrying the two-dimensional network silica nanostructure were significantly enhanced.

[0081] It should be noted that the dispersion of the two-dimensional network silica nanostructure can also be dispersed on optical glass with other structures, so that the optical glass also has significant hydrophobicity and light transmittance.

[0082] The specific process of dispersing the dispersion of the two-dimensional network silica nanostructure on the surface of the heterojunction solar cell or optical glass can be: using a syringe to slowly inject the dispersion of the two-dimensional network silica nanostructure onto the surface of ultrapure water, using an immersion puller to fix the cleaned heterojunction solar cell or optical glass, and performing coating to achieve anti-reflection and hydrophobic effects at the same time.

[0083] The above is a detailed introduction to the preparation method of silicon dioxide nanoparticles and heterojunction solar cells provided by the present invention. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core concept. At the same time, for those skilled in the art, according to the concept of the present invention, there may be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as limiting the present invention.

[0084] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Reference can be made to the common and similar parts between the various embodiments. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the method description.

[0085] It should also be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that the process, method, article, or apparatus comprising a series of elements inherent to the elements, or also including elements inherent to these processes, methods, articles, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus comprising the element.

[0086] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing silicon dioxide nanoparticles, characterized in that: The method for preparing the silicon dioxide nanoparticles comprises: Dispersing tetraethyl orthosilicate in anhydrous ethanol to obtain a silicon source precursor; Dissolving an organic amine catalyst in a mixed solution of water and ethanol, and stirring at a first speed to obtain a target solution; Adding the silicon source precursor to the target solution and stirring at a second speed, and performing temperature control during the stirring process, to react and obtain silicon dioxide nanoparticles; The silica nanoparticles are washed by alternating centrifugation with ethanol and water at a third speed, and dried to obtain a two-dimensional network silica nanostructure; wherein the two-dimensional silica nanoparticles in the two-dimensional network silica nanostructure are composed of long circular chains, and the network gaps are filled with air.

2. The method for preparing silicon dioxide nanoparticles according to claim 1, characterized in that: The volume range of the tetraethyl orthosilicate is 1 ml to 6 ml; The volume range of the anhydrous ethanol is 8ml-48ml.

3. The method for preparing silicon dioxide nanoparticles according to claim 1, characterized in that: The weight range of the organic amine catalyst is 0.1g-1.0g; The volume of water in the mixed solution ranges from 35 ml to 45 ml, and the volume of ethanol in the mixed solution ranges from 15 ml to 25 ml.

4. The method for preparing silicon dioxide nanoparticles according to claim 1, characterized in that: The organic amine catalyst is a dodecylamine catalyst or a hexadecylamine catalyst.

5. The method for preparing silicon dioxide nanoparticles according to claim 1, characterized in that: The first speed ranges from 800 rpm to 1200 rpm, and the duration of stirring at the first speed ranges from 1 min to 3 min.

6. The method for preparing silicon dioxide nanoparticles according to claim 1, characterized in that: The speed range of the second speed is 250 rpm-350 rpm, and the duration range of stirring at the second speed is 3 h-4.5 h.

7. The method for preparing silicon dioxide nanoparticles according to claim 1, characterized in that: The third speed ranges from 7000 rpm to 9000 rpm, and the duration of alternating centrifugal washing at the third speed ranges from 4 min to 6 min; The drying temperature range of the drying process is 75° C.-85° C., and the drying duration range of the drying process is 8 h-12 h.

8. The method for preparing silicon dioxide nanoparticles according to claim 1, characterized in that: The temperature range of the temperature control treatment is 45° C.-65° C., and the duration range of the temperature control treatment is 2 h-5 h.

9. A method for preparing a heterojunction solar cell, characterized in that: The preparation method of the heterojunction solar cell comprises: A dispersion of a two-dimensional network silica nanostructure is prepared according to any one of claims 1 to 8; The dispersion liquid of the two-dimensional network silicon dioxide nanostructure is dispersed on the surface of a heterojunction solar cell and dried to obtain a heterojunction solar cell having a film layer of the two-dimensional network silicon dioxide nanostructure.

10. The method for preparing a heterojunction solar cell according to claim 9, characterized in that: The dispersion liquid configured with the two-dimensional network silica nanostructure comprises: Dispersing the two-dimensional network silica nanostructure in a mixed solution and performing ultrasonic treatment; The volume range of the mixed solution is 8 ml-12 ml, the mixed solution is a mixed solution of chloroform and ethanol, and the volume ratio of chloroform:ethanol in the mixed solution is in the range of 4:1 to 5:1.

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