CN112442669A

CN112442669A - Preparation method of self-cleaning antireflection film

Info

Publication number: CN112442669A
Application number: CN202011321176.9A
Authority: CN
Inventors: 姚函妤; 唐群涛; 巨佳; 王龙龙; 刘佳琦; 申亚宁; 王帅康; 吴心怡
Original assignee: Nanjing Institute of Technology
Current assignee: Nanjing Institute of Technology
Priority date: 2020-11-23
Filing date: 2020-11-23
Publication date: 2021-03-05
Anticipated expiration: 2040-11-23
Also published as: CN112442669B

Abstract

The invention discloses a method for preparing a self-cleaning anti-reflection film, comprising the following steps: Step 1: take a cleaned glass substrate, place it in a chamber of a magnetron sputtering device, and use a metal target and a silicon dioxide target for co-sputtering Step 2: Immerse the deposited glass substrate in a special demetallization solution, oscillate ultrasonically for 0.5-1h, and perform wet etching to obtain a silicon dioxide film; Step 3: Wash the demetallized glass substrate with flowing water Clean, and then immerse in dilute hydrochloric acid solution to remove excess lye; Step 4: Take out the neutralized and cleaned glass substrate, rinse it with running water, dry the surface, and place it in an annealing furnace for annealing at 300‑500℃ for 1‑ For 2h, the silicon dioxide thin film is crystallized, and finally a silicon dioxide crystalline thin film with a hole structure is obtained on the glass substrate. The preparation method of the self-cleaning anti-reflection film provided by the invention can play the dual functions of self-cleaning and anti-reflection.

Description

Preparation method of self-cleaning antireflection film

Technical Field

The invention relates to a preparation method of a self-cleaning antireflection film, and belongs to the technical field of film materials.

Background

The advantages of the glass such as transparency, high temperature resistance, corrosion resistance and easiness in preparation of various shapes enable the glass to be widely applied to daily life and industrial production. For example, the solar cell is covered on a light absorption surface of the solar cell as a protection device, which can ensure high solar light transmittance and prevent the solar cell from being damaged by rain, dust, gas and the like.

Due to the different propagation rates of light in different media (different refractive indexes of the media), when light enters another medium from one medium, a reflection phenomenon occurs at the interface of the media, and the transmittance of the light is reduced. This phenomenon is very disadvantageous for products requiring transparent protection, such as solar cell modules, and the high reflectivity of the surface of the encapsulation glass leads to reduced absorption of light by the cell, thereby reducing its photoelectric conversion efficiency. In addition, if the glass is often exposed to severe environments (such as wind sand and rain), the transmittance of the glass is also reduced due to the adsorption of dust and water on the glass. With the increasing application of glass in the fields of solar cells and the like, the requirements on the self-cleaning function of glass and the reduction of light reflection phenomena are higher and higher.

In the prior art, methods for reducing the light reflection phenomenon of glass include: growing magnesium fluoride with low refractive index of 60nm on a common silicon dioxide glass substrate with the thickness of 5mm, then superposing niobium oxide with high refractive index of 10nm, further superposing titanium oxide with high refractive index of 10nm, further superposing silicon dioxide with low refractive index of 60nm, and further superposing silicon nitride with medium refractive index of 15 nm. The above-mentioned superimposed film can be formed into refractive index gradient change, and can reduce reflectivity and raise transmittance.

That is, at present, the common glass antireflection method is to plate multiple functional thin films, i.e. high refractive index, low refractive index, high refractive index, and low refractive index layers are laminated to obtain a film structure with gradually changed refractive index. Such a film structure inevitably leads to complexity and high cost of production. Moreover, the fixed oxide film has a specific refractive index, and the overall refractive index can only be adjusted by repeatedly stacking different types of films, but this causes the overall thickness of the glass to increase, so that the effect of increasing the transmittance is not significant. In addition, the method can not cause the glass to have self-cleaning effect.

In addition, in the prior art, the technical scheme for realizing self-cleaning of glass includes: the glass substrate is prepared by melting and sintering quartz sand, aluminum hydroxide, soda ash, boric acid and calcite at a high temperature, so that the glass substrate has a silicon dioxide surface and achieves the self-cleaning effect. The self-cleaning glass prepared by sintering causes cost rise, and the technology is complex and single and cannot be applied to a plurality of finished glass products.

Disclosure of Invention

The purpose of the invention is as follows: in order to overcome the defects in the prior art, the invention provides a preparation method of a self-cleaning antireflection film, which can solve the problem that when glass is used as an encapsulation material, the transmittance of light entering the glass from air is increased, and on the other hand, the glass prepared by the method has a super-hydrophobic structure, and can prevent the transmittance from being reduced due to the fact that the surface is polluted by dust, water stain and the like.

In order to solve the technical problems, the technical scheme adopted by the invention is as follows:

a preparation method of a self-cleaning antireflection film comprises the following steps:

the method comprises the following steps: putting a cleaned glass substrate in a chamber of a magnetron sputtering device, and depositing a metal particle and silicon dioxide mixture film on the glass substrate by adopting co-sputtering of a metal target and a silicon dioxide target;

step two: immersing the glass substrate after deposition into a metal removing solution, carrying out ultrasonic oscillation for 0.5-1h, and carrying out wet etching to obtain a silicon dioxide film;

step three: cleaning the glass substrate with the metal removed by using flowing water, and then immersing the glass substrate into a dilute hydrochloric acid solution to remove redundant alkali liquor;

step four: and taking out the neutralized and cleaned glass substrate, washing the glass substrate by using flowing water, drying the surface of the glass substrate, and annealing the glass substrate in an annealing furnace at the temperature of 300-500 ℃ for 1-2h to crystallize the silicon dioxide film, thereby finally obtaining the silicon dioxide crystallized film with the hole structure on the glass substrate.

The power of the metal target is 70W-20W, the power of the silicon dioxide target is 50-150W, and the thickness of the obtained mixture film is 50 nm.

The power of the metal target is 70W-20W, the power of the silicon dioxide target is 50W-150W, the power of the metal target is increased by 10W every 2min in the sputtering process, and the thickness of the obtained mixture film is 126 nm.

The content of the metal particles in the mixture film gradually increases from the surface of the glass substrate to the outer surface of the mixture film.

The preparation method of the metal removing solution comprises the following steps: adding 30mL of 5-30% hydrogen peroxide into 100mL of 5-30% ammonia water, diluting with 200mL of ultrapure water, adding various surfactants into the diluted solution, wherein the various surfactants comprise 1-10g of sodium lauryl sulfate, 1-5g of sodium glycocholate, 1-4.5g of sodium dioctyl succinate, 5-50mL of coconut diethanolamide and 1-5g of polyoxyethylene lanolin, and heating at 20-50 ℃ and uniformly stirring until the mixture is fully dissolved to form a homogeneous solution.

The surface drying is to dry the surface by adopting nitrogen.

The concentration of the dilute hydrochloric acid solution is 2-5%.

The refractive index of the silicon dioxide crystalline film is 1.21-1.32, and the contact angle of the silicon dioxide crystalline film and a water drop is 137-141 degrees.

The material of the metal target comprises copper, silver, nickel, gold, iron, tin or aluminum.

The glass substrate comprises ultra-white float glass, soda-lime glass, quartz glass or a silicon wafer.

The invention has the following beneficial effects:

1. the invention provides a self-cleaning antireflection film capable of being deposited on glass, which can play double roles of self-cleaning and antireflection.

2. According to the invention, metal copper particles are combined with the silicon dioxide dielectric film, the power of a sputtering copper target is adjusted to control the copper metal content, and the mixed film with the copper content changing in a gradient manner is prepared, so that the content of the copper metal particles is high at a position far away from a glass substrate, the formed porosity is high, and the porosity of a part close to the glass substrate is low, so that the gradient of refractive index from low to high is presented in the film, and the effect on reducing light reflection and increasing light transmission is better.

3. The invention adopts special metal removing solution to carry out wet etching, creates a silicon dioxide film layer with a certain porosity structure, and realizes that the refractive index of the silicon dioxide film is adjustable. The invention can also form a silicon dioxide film layer with gradient and gradual change of porosity, thereby realizing gradient change of the refractive index of the silicon dioxide antireflection film.

4. According to the invention, the super-hydrophobic structure is realized through the hole structure of the film, no additional hydrophobic material is needed to be added, and the self-cleaning effect is realized while the reflection is reduced.

5. According to the invention, because the copper particles in the mixture film formed by co-sputtering are as small as nanometer level, when the mixture film is corroded by common acid liquor, the holes left after the copper on the surface is corroded are at nanometer level, so that the solution can not be better immersed into the film to corrode redundant copper particles, and the residual copper is left in the film to prevent light waves from entering the film. The invention adopts multiple surfactants to regulate the surface energy of the solution, and ensures that the metal-removing solution can smoothly enter the film, thereby thoroughly removing copper particles.

6. The invention is simple and controllable, and can realize mass production by adopting the existing assembly line equipment; the refractive index of the porous film is simple and controllable, the refractive index gradient and gradual change can be easily formed, and the achievement in the aspect of reducing the reflectivity is remarkable. The film has high bonding force with a glass substrate, and has wide selection range of glass substrate materials, such as ultra-white float glass, common soda-lime glass, quartz glass and the like. The self-cleaning antireflection film can be prepared even on the surface of a device directly, for example, the self-cleaning antireflection film is directly grown on the surface of a silicon wafer. The invention can also realize the self-cleaning effect, common oxide antireflection films are all hydrophilic structures, and a hydrophobic film needs to be grown for realizing the hydrophobic structure.

Drawings

FIG. 1 is a flow chart of the present invention;

FIG. 2 is a graph showing the contact angle of a water droplet with a film of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. The specific embodiments described herein are merely illustrative of the invention and are not intended to be limiting.

Example 1:

the preparation flow of this embodiment is as shown in fig. 1, and a method for preparing a self-cleaning anti-reflection film includes cleaning a glass substrate with a length and a width of 300mm and a thickness of 3mm according to a standard flow, and placing the cleaned glass substrate in a chamber of a magnetron sputtering apparatus. A copper metal particle and silicon dioxide mixture film is deposited on a glass substrate by co-sputtering with a power of 50W of a copper target and a power of 120W of a silicon dioxide target, and the thickness of the obtained mixture film is 50 nm.

And soaking the glass substrate after deposition into a special metal removing solution without any protection and mask for simple wet etching, standing for 1h, and adding ultrasonic oscillation during standing to accelerate the dissolution of copper particles.

The preparation method of the metal removing solution comprises the following steps:

adding 30mL of 30% hydrogen peroxide into 100mL of 25% ammonia water, diluting with 200mL of ultrapure water, respectively adding a plurality of surfactants, namely 10g of sodium lauryl sulfate, 5g of sodium glycocholate, 4.5g of sodium dioctyl sulfosuccinate, 50mL of coconut diethanolamide and 3g of polyoxyethylene lanolin, into the diluted solution, heating to 50 ℃, and uniformly stirring until the mixture is fully dissolved to form a homogeneous solution.

Because the copper particles in the mixture film formed by co-sputtering are as small as nanometer level, when the mixture film is corroded by common acid liquor, the holes left after the copper on the surface is corroded are at nanometer level, so that the solution can not be better immersed into the film to corrode redundant copper particles, and residual copper is left in the film to prevent light waves from entering the film. In the embodiment, the surface energy of the solution is regulated by adopting multiple surfactants, so that the metal removing solution can smoothly enter the film, and copper particles are thoroughly removed.

And cleaning the glass substrate subjected to wet etching by using flowing water, and then soaking the glass substrate into a dilute hydrochloric acid solution with the concentration of 2% to remove redundant alkali liquor.

And taking out the neutralized and cleaned glass substrate, washing the glass substrate by using flowing water, drying the glass substrate by using nitrogen on the surface, and annealing the glass substrate in an annealing furnace at 500 ℃ for 2 hours to crystallize the silicon dioxide film, thereby finally obtaining the silicon dioxide crystallized film with a hole structure on the glass substrate.

The silica crystalline film was tested to have a refractive index of 1.32. The refractive index of air is 1, the refractive index of silicon dioxide is 1.5, and the refractive index of the silicon dioxide film is effectively reduced due to the existence of a hole structure in the silicon dioxide crystalline film, so that a refractive index gradient is formed between the air and the glass with the main component of silicon dioxide. Meanwhile, because of the deposition nonuniformity of the copper metal particles, the silicon dioxide crystalline film with the thickness of 50nm also has gradual change of refractive index, thereby reducing the reflection of light and increasing the transmittance of the light. The transmittance at a light wavelength of 550nm increased from 96.2% to 97.3% of that of ordinary glass.

As shown in FIG. 2, the contact angle of the silicon dioxide crystalline film and a water drop is 137 degrees when the silicon dioxide crystalline film is tested, and due to the existence of the hole structure in the silicon dioxide crystalline film, the contact angle between the water drop and the film layer is increased, the hydrophilic structure on the surface of the common glass is modified into the super-hydrophobic structure, and the possibility of water stain and dust contamination is reduced.

Example 2:

a preparation method of a self-cleaning antireflection film comprises the steps of cleaning a glass substrate with the length and the width of 300mm and the thickness of 3mm according to a standard process, and placing the cleaned glass substrate in a chamber of a magnetron sputtering device. Co-sputtering by adopting 70W-20W of power of a copper target and 120W of power of a silicon dioxide target, increasing the power of the copper target by 10W every 2min in the sputtering process, and depositing a mixture film of copper metal particles and silicon dioxide on a glass substrate, wherein the thickness of the obtained mixture film is 126 nm.

And soaking the glass substrate after deposition into a metal removing solution without any protection and mask for simple wet etching, standing for 0.5h, and adding ultrasonic oscillation during standing to accelerate the dissolution of copper particles.

adding 30mL of 5% hydrogen peroxide into 100mL of 5% ammonia water, diluting with 200mL of ultrapure water, respectively adding various surfactants, namely 1g of sodium lauryl sulfate, 1g of sodium glycocholate, 1g of sodium dioctyl sulfosuccinate, 5mL of coconut diethanolamide and 1g of polyoxyethylene lanolin, into the diluted solution, heating at 20 ℃, and uniformly stirring until the mixture is fully dissolved to form a homogeneous solution.

And cleaning the glass substrate subjected to wet etching by using flowing water, and then soaking the glass substrate into an aqueous solution containing 5% of dilute hydrochloric acid to neutralize and remove redundant alkali liquor in the metal solution.

The refractive index of the entire crystalline silica thin film of this example was tested to be 1.21. Since the copper metal particles are contained in a high content at a position far from the glass substrate, the porosity of the formed film is high, and the porosity of a portion near the glass substrate is low, so that the silica crystalline thin film of the present embodiment has a gradient of refractive index from low to high, and the effect of reducing light reflection and increasing light transmission is better. The transmittance at a light wavelength of 550nm was 98.2%.

The contact angle of the crystalline silicon dioxide film of the embodiment with water drops is 141 degrees, and the crystalline silicon dioxide film is also of a super-hydrophobic structure, so that the possibility of water stain and dust contamination is reduced.

Example 3:

this example differs from example 1 only in that: co-sputtering was performed using a power of 20W for the copper target and a power of 150W for the silicon dioxide target. And step four, annealing for 1h at 300 ℃ in an annealing furnace.

adding 30mL of 20% hydrogen peroxide into 100mL of 30% ammonia water, diluting with 200mL of ultrapure water, respectively adding various surfactants, namely 5g of sodium lauryl sulfate, 3g of sodium glycocholate, 3g of sodium dioctyl sulfosuccinate, 30mL of coconut diethanolamide and 5g of polyoxyethylene lanolin, into the diluted solution, heating to 35 ℃, and uniformly stirring until the mixture is fully dissolved to form a homogeneous solution.

The refractive index of the entire crystalline silica thin film of this example was tested to be 1.22. The transmittance at a light wavelength of 550nm was 98.7%.

Example 4:

this example differs from example 1 only in that: co-sputtering was performed using a power of 70W for the copper target and 50W for the silicon dioxide target. And step four, annealing for 1.5 hours at 400 ℃ in an annealing furnace.

Example 5:

this example differs from example 2 only in that: the power of the silica target was 50W.

Example 6:

this example differs from example 2 only in that: the power of the silica target was 150W.

Example 7:

this example differs from example 1 only in that: the copper particles (i.e., the material of the copper target) can be replaced by other metal particles, such as silver, nickel, gold, iron, tin, aluminum, etc., which can be corroded by the demetallizing solution to form a metal salt soluble in water.

The glass substrate comprises any one of ultra-white float glass, soda-lime glass, quartz glass and silicon wafers.

The foregoing shows and describes the general principles, essential features, and advantages of the invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.

Claims

1. A preparation method of a self-cleaning antireflection film is characterized by comprising the following steps: the method comprises the following steps:

2. The method of claim 1, wherein the self-cleaning anti-reflective film comprises: the power of the metal target is 70W-20W, the power of the silicon dioxide target is 50-150W, and the thickness of the obtained mixture film is 50 nm.

3. The method of claim 1, wherein the self-cleaning anti-reflective film comprises: the power of the metal target is 70W-20W, the power of the silicon dioxide target is 50W-150W, the power of the metal target is increased by 10W every 2min in the sputtering process, and the thickness of the obtained mixture film is 126 nm.

4. The method of claim 3, wherein said self-cleaning anti-reflective film is prepared by: the content of the metal particles in the mixture film gradually increases from the surface of the glass substrate to the outer surface of the mixture film.

5. The method of claim 1, wherein the self-cleaning anti-reflective film comprises: the preparation method of the metal removing solution comprises the following steps: adding 30mL of 5-30% hydrogen peroxide into 100mL of 5-30% ammonia water, diluting with 200mL of ultrapure water, adding various surfactants into the diluted solution, wherein the various surfactants comprise 1-10g of sodium lauryl sulfate, 1-5g of sodium glycocholate, 1-4.5g of dioctyl sodium sulfosuccinate, 5-50mL of coconut diethanolamide and 1-5g of polyoxyethylene lanolin, and heating at 20-50 ℃ to stir uniformly until the mixture is fully dissolved to form a homogeneous solution.

6. The method of claim 1, wherein the self-cleaning anti-reflective film comprises: the surface drying is to dry the surface by adopting nitrogen.

7. The method of claim 1, wherein the self-cleaning anti-reflective film comprises: the concentration of the dilute hydrochloric acid solution is 2-5%.

8. The method of claim 1, wherein the self-cleaning anti-reflective film comprises: the refractive index of the silicon dioxide crystalline film is 1.21-1.32, and the contact angle of the silicon dioxide crystalline film and a water drop is 137-141 degrees.

9. The method of claim 1, wherein the self-cleaning anti-reflective film comprises: the material of the metal target comprises copper, silver, nickel, gold, iron, tin or aluminum.

10. The method of claim 1, wherein the self-cleaning anti-reflective film comprises: the glass substrate comprises ultra-white float glass, soda-lime glass, quartz glass or a silicon wafer.