阅读说明：本技术 一种ZnO-SiO2双涂层的下转换减反射膜及其制备方法 (ZnO-SiO2Double-coating down-conversion antireflection film and preparation method thereof ) 是由 黄建勇 费广涛 许少辉 于 2021-10-11 设计创作，主要内容包括：本发明属于纳米材料领域,特别涉及一种ZnO-SiO-(2)双涂层的下转换减反射膜及其制备方法。本发明采用溶胶-凝胶法,先在玻璃基片上制备一层ZnO下转换涂层,然后烘干再镀制一层SiO-(2)涂层,将ZnO量子点作为下转换发光材料,ZnO材料无毒,原料成本低,而且在400-1100nm具有很高的透明性；SiO-(2)涂层可以保护ZnO涂层,使其不被腐蚀,还可以显著提高透过率。所获得的双层减反射涂层,具有很好的增透和下转换发光的双重作用,解决了现有技术中发光材料与减反射膜复合时的不匹配问题。(The invention belongs to the field of nano materials, and particularly relates to ZnO-SiO 2 A double-coating down-conversion antireflection film and a preparation method thereof. The invention adopts a sol-gel method to prepare a ZnO down-conversion coating on a glass substrate, then the ZnO down-conversion coating is dried and plated with a SiO layer 2 The coating takes ZnO quantum dots as a down-conversion luminescent material, the ZnO material is nontoxic, the cost of the raw material is low, and the ZnO quantum dots have high transparency at 400-1100 nm; SiO 2 2 The coating can protect the ZnO coating from being corroded and can also obviously improve the transmittance. The obtained double-layer antireflection coating has good dual functions of antireflection and down-conversion luminescence, and solves the problem of mismatching of luminescent materials and antireflection films in the prior art.)

1. ZnO-SiO₂The down-conversion antireflection film with double coatings is characterized by sequentially comprising a glass substrate, a ZnO coating and SiO from bottom to top in structure₂A coating, wherein the ZnO coating has a thickness of 80-150nm, and the SiO is₂The thickness of the coating is 100-200 nm.

2. The ZnO-SiO of claim 1₂The preparation method of the down-conversion antireflection film with the double coatings is characterized by comprising the following steps of:

s1, preparing ZnO quantum dot coating liquid: preparing ZnO quantum dots by a sol-gel method, dispersing the ZnO quantum dots in absolute ethyl alcohol, and preparing clear ZnO quantum dot coating liquid with the concentration of 0.2-2 mol/L;

s2 preparation of basic SiO₂Sol: preparing alkaline SiO by sol-gel method with tetraethyl orthosilicate TEOS as silicon source, ammonia water as catalyst and absolute ethyl alcohol as solvent₂Sol of SiO₂The concentration of the alcohol is 0.5-0.8mol/L, and the alcohol is aged for 3-7 days at room temperature for standby;

s3, plating a ZnO coating on the glass substrate: pulling a coating film in the ZnO quantum dot coating liquid by using the cleaned glass substrate to obtain the glass substrate plated with the ZnO coating, and drying for later use;

s4, plating SiO on the ZnO coating₂Coating: aging for 3-7 days with alkaline SiO₂HNO for sol₃Adjusting the pH value of the sol to 5-7, then pulling the glass substrate coated with the ZnO coating in the sol for coating, and drying in an oven after coating to obtain the ZnO-SiO₂A dual-coated down-conversion antireflection film;

wherein, the steps S2 and S3 are not in sequence.

3. The ZnO-SiO of claim 2₂The preparation method of the double-coating down-conversion antireflection film is characterized in that the preparation steps of the ZnO quantum dots in the step S1 are as follows:

s11, weighing 2.4g of zinc acetate dihydrate, adding the zinc acetate dihydrate into 30-50ml of absolute ethyl alcohol, stirring for 40-60min in a water bath kettle at the temperature of 60 ℃, adjusting the water bath temperature to 28-32 ℃, and reducing the temperature of the solution to a constant temperature, and marking as solution A;

s12, adding 0.45g of KOH into 20-30ml of absolute ethyl alcohol, and stirring until the KOH is dissolved to obtain an ethanol solution of potassium hydroxide, which is marked as solution B;

and S13, adding the solution B into the solution A, stirring until the mixed solution becomes clear, adding n-hexane with the volume 2-3 times of that of the clear solution into the clear solution to generate white precipitate, standing for 10-20min, centrifuging, and washing to obtain the ZnO quantum dot.

4. The ZnO-SiO of claim 2₂The preparation method of the down-conversion antireflection film with double coatings is characterized in that the basic SiO in the step S2₂The preparation method of the sol comprises the following steps:

s21, tetraethyl orthosilicate (TEOS) and absolute ethyl alcohol (EtOH) are mixed according to the molar ratio of TEOS: mixing EtOH 1:10, and stirring for 20-30min at room temperature by magnetic force to obtain solution C;

s22, mixing H₂O, EtOH and NH₃·H₂O is H in a molar ratio₂O:EtOH:NH₃·H₂O is 5: 10, (0.2-0.5) mixing, and stirring for 2-3min at room temperature by magnetic force to obtain a solution D;

s23, slowly adding the solution C into the solution D with stirring, wherein the molar ratio of the substances in the mixed solution of C and D is TEOS: EtOH: H₂O:NH₃·H₂O is 1:20:5 (0.2-0.5), the mixed solution is placed in a constant temperature water bath kettle for magnetic stirring, the stirring speed is set to be 500-₂And (3) sol.

5. The ZnO-SiO of claim 2₂The preparation method of the down-conversion antireflection film with the double coatings is characterized in that the cleaning step of the glass substrate in the step S3 is as follows: soaking a glass substrate with a proper size in a 5-10 wt% sodium hydroxide solution for 20-30min, taking out, washing under tap water, wiping with silk cloth, washing with deionized water, soaking in absolute ethyl alcohol, pouring off the absolute ethyl alcohol, and drying for later use.

6. The ZnO-SiO of claim 2₂The method for preparing a double-coated down-conversion antireflection film is characterized in that the coating is pulled in the steps S3 and S4The body parameters are: when the film is pulled up, the descending speed is 50-100mm/min, the dipping time of the glass substrate in the dispersion liquid is 30-60s, and the ascending speed is 50-100 mm/min.

Technical Field

The invention belongs to the field of nano materials, and particularly relates to a ZnO down-conversion coating layer as a bottom layer and SiO as a top layer₂A film which consists of an antireflection film coating and has down-conversion and antireflection functions and a preparation method thereof.

Background

In recent years, with the rapid development of society and the increasing global energy consumption, energy shortage has become an increasingly important issue. Solar energy is receiving attention as a renewable energy source, but at present, the photovoltaic conversion efficiency of solar cells is not high. On one hand, the band gap energy (main response wavelength is 400-1100nm) of the silicon semiconductor is not completely matched with the solar spectrum (250-2500nm), which limits the energy efficiency, and the loss of the spectral mismatch accounts for more than 60% of the energy loss of the solar cell. On the other hand, the surfaces of solar cells and photovoltaic glass may reflect sunlight, causing energy loss.

The antireflection film can effectively eliminate or reduce reflection of incident light, but the solar cell still cannot utilize energy other than the response wavelength. Most of the high-energy ultraviolet light cannot be utilized by the solar cell, so that the efficiency of the solar cell is greatly reduced, and in addition, the ultraviolet light can accelerate the aging of the solar cell and reduce the service life of the solar cell. The down-converting material may convert ultraviolet light into visible or near-infrared light for absorption and utilization by the solar cell. Therefore, the down-conversion luminescence can reduce the harmful effect of ultraviolet illumination on the solar cell and improve the photoelectric conversion efficiency of the solar cell.

Rare earth ions or quantum dots are generally used as down-conversion luminescent materials, and are doped or compounded into an antireflection film to obtain a film which can reduce light reflection and has the dual functions of down-conversion luminescence. However, the light emitting material is often poorly matched to the antireflection film, resulting in a decrease in the original antireflection effect of the antireflection film. For example, R u bia et al convert rare earth Er³⁺Although the antireflection film has light conversion performance, the average transmittance of the antireflection film plated on the glass substrate after being compounded in the visible light and near infrared bands is reduced by 7% (Solar Energy 170(2018) 752-761). Moreover, when a light emitting material is compounded into the antireflection film, the amount of the added light emitting material is greatly limited, which also limits the improvement of the down-conversion light emission intensity. The application of down-conversion luminescence in photovoltaics is still a challenging issue.

Disclosure of Invention

The invention aims to solve the technical problem of mismatching of a luminescent material and an antireflection film during compounding in the prior art, and provides ZnO-SiO with down-conversion and antireflection functions₂A double-coating down-conversion antireflection film and a preparation method thereof.

In order to solve the technical problem of the invention, the technical scheme adopted is that ZnO-SiO₂The down-conversion antireflection film with double coatings structurally comprises a glass substrate, a ZnO coating and SiO sequentially from bottom to top₂A coating, wherein the ZnO coating has a thickness of 80-150nm, and the SiO is₂The thickness of the coating is 100-200 nm.

In order to solve the technical problem of the invention, another technical scheme is that ZnO-SiO₂The preparation method of the down-conversion antireflection film with the double coatings comprises the following steps:

s1, preparing ZnO quantum dot coating liquid: preparing ZnO quantum dots by a sol-gel method, dispersing the ZnO quantum dots in absolute ethyl alcohol, and preparing clear ZnO quantum dot coating liquid with the concentration of 0.2-2 mol/L;

s2 preparation of basic SiO₂Sol: preparing alkaline SiO by sol-gel method with tetraethyl orthosilicate TEOS as silicon source, ammonia water as catalyst and absolute ethyl alcohol as solvent₂Sol of SiO₂The concentration of the alcohol is 0.5-0.8mol/L, and the alcohol is aged for 3-7 days at room temperature for standby;

s3, plating a ZnO coating on the glass substrate: pulling a coating film in the ZnO quantum dot coating liquid by using the cleaned glass substrate to obtain the glass substrate plated with the ZnO coating, and drying for later use;

s4, plating SiO on the ZnO coating₂Coating: aging for 3-7 days with alkaline SiO₂HNO for sol₃Adjusting the pH value of the sol to 5-7, then pulling the glass substrate coated with the ZnO coating in the sol for coating, and drying in an oven after coating to obtain the ZnO-SiO₂A dual-coated down-conversion antireflection film;

wherein, the steps S2 and S3 are not in sequence.

As ZnO-SiO₂The preparation method of the down-conversion antireflection film with the double coating is further improved:

preferably, the sol-gel method for preparing the ZnO quantum dots comprises the following steps:

s11, weighing 2.4g of zinc acetate dihydrate, adding the zinc acetate dihydrate into 30-50ml of absolute ethyl alcohol, stirring for 40-60min in a water bath kettle at the temperature of 60 ℃, adjusting the water bath temperature to 28-32 ℃, and reducing the temperature of the solution to a constant temperature, and marking as solution A;

s12, adding 0.45g of KOH into 20-30ml of absolute ethyl alcohol, and stirring until the KOH is dissolved to obtain an ethanol solution of potassium hydroxide, which is marked as solution B;

and S13, adding the solution B into the solution A, stirring until the mixed solution becomes clear, adding n-hexane with the volume 2-3 times of that of the clear solution into the clear solution to generate white precipitate, standing for 10-20min, centrifuging, and washing to obtain the ZnO quantum dot.

Preferably, the basic SiO in step S2₂The preparation method of the sol comprises the following steps:

s21, tetraethyl orthosilicate (TEOS) and absolute ethyl alcohol (EtOH) are mixed according to the molar ratio of TEOS: mixing EtOH 1:10, and stirring for 20-30min at room temperature by magnetic force to obtain solution C;

s22, mixing H₂O, EtOH and NH₃·H₂O is H in a molar ratio₂O:EtOH:NH₃·H₂O is 5: 10, (0.2-0.5) mixing, and stirring for 2-3min at room temperature by magnetic force to obtain a solution D;

s23, slowly adding the solution C into the solution D with stirring, wherein the molar ratio of the substances in the mixed solution of C and D is TEOS: EtOH: H₂O:NH₃·H₂O ═ 1:20:5 (0.2-0.5). The mixed solution is placed in a constant temperature water bath kettle for magnetic stirring, the stirring speed is set to be 500-₂And (3) sol.

Preferably, the cleaning step of the glass substrate in step S3 is as follows: soaking a glass substrate with a proper size in a 5-10 wt% sodium hydroxide solution for 20-30min, taking out, washing under tap water, wiping with silk cloth, washing with deionized water, soaking in absolute ethyl alcohol, pouring off the absolute ethyl alcohol, and drying for later use.

Preferably, the specific parameters of the pulling coating film in the steps S3 and S4 are as follows: when the film is pulled up, the descending speed is 50-100mm/min, the dipping time of the glass substrate in the dispersion liquid is 30-60s, and the ascending speed is 50-100 mm/min.

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

(1) the invention avoids the mismatching problem when the luminescent material is compounded with the antireflection film, and prepares the down-conversion luminescent material into the down-conversion coating; firstly, a ZnO down-conversion coating is prepared on a glass substrate, then the glass substrate is dried and then a SiO layer is plated₂And (4) coating. The ZnO quantum dots can absorb light before 400nm and mainly emit light between 500-600nm, the ZnO material has high transparency in the 400-1100nm waveband, the refractive index of the coating prepared from the ZnO quantum dots is high, and the transmittance is reduced when the coating is plated on the surface of photovoltaic glass. Moreover, ZnO is an amphoteric oxide, and ZnO materials are unstable in an acidic environment with the pH lower than 6.0 or an alkaline solution with the pH higher than 10.0, so that ZnO quantum dot films are easy to corrode when exposed outside. Thus, a layer of low refractive index SiO is plated on the ZnO coating₂The coating can increase the transmission and protect the ZnO coating. The obtained double-layer antireflection coating has good dual functions of antireflection and down-conversion luminescence.

(2) ZnO quantum dots are used as down-conversion luminescent materials, the ZnO materials are nontoxic, the raw material cost is low, and the ZnO quantum dots have high transparency at 400-1100 nm; SiO 2₂The coating can protect the ZnO coating from being corroded and can also obviously improve the transmittance. ZnO quantum dot and SiO of the invention₂The sol is prepared by sol-gel method, ZnO coating and SiO₂The thickness of the coating can be adjusted according to the coating times, the concentration of the coating liquid and the pulling speed, the process is mature, and the operation is simple. The double-layer coating does not need annealing treatment, and has the anti-reflection effect and down-conversion luminescence property.

Drawings

FIG. 1 is a SEM photograph of a thin film in which (a) SiO₂Sol adjusted to weakly acidic film plane after coating, (b) SiO₂Sol is adjusted to be the section of the film after weak acid coating, and (c) ZnO-SiO₂Upper surface of double-layer film, (d) ZnO-SiO₂The thickness of the double-layer film;

FIG. 2 shows ZnO coating and ZnO-SiO₂Double layer coating on glass and pure glass transmittance；

FIG. 3 shows pure glass, a single-layer ZnO coating film of comparative example 2, and ZnO-SiO prepared in example 2₂The double-layer coating film has an emission peak tested by 365nm light excitation;

FIG. 4 shows ZnO-SiO of example 2₂The double-layer coating film is excited by 365nm light to obtain an emission peak.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to embodiments, and all other embodiments obtained by a person of ordinary skill in the art without any creative effort based on the embodiments of the present invention belong to the protection scope of the present invention.

Comparative example 1

The preparation method of the single-layer ZnO coating film comprises the following steps:

s1, preparing the ZnO quantum dots by adopting a sol-gel method: a cylinder was used to measure 40ml of absolute ethanol, which was added to a conical flask, followed by 2.4g of zinc acetate dihydrate (Zn (AC)₂·2H₂O) is added into absolute ethyl alcohol, then the mixture is put into a water bath kettle with the temperature set to 60 ℃ to be stirred for 40-60min, and then the temperature of the water bath is adjusted to 30 ℃. After the temperature was decreased to 30 deg.C, a KOH ethanol solution (wherein KOH was 0.45g, and absolute ethanol was 20ml) was added. Stirring for several minutes until the mixed solution becomes clear. And adding a normal hexane solution with the volume being 3 times that of the clear solution, quickly generating white precipitate in the clear solution, standing for 10min, and centrifuging to obtain the ZnO quantum dots after the precipitate is completely finished. And dispersing the centrifuged ZnO quantum dots in absolute ethyl alcohol to prepare the clear ZnO quantum dot coating liquid. Wherein the concentration of the ZnO quantum dots is 0.5 mol/L;

s2, pulling and coating: the coating liquid of the ZnO quantum dots is used for coating on a cleaned glass substrate in a pulling coating mode. And (3) when the coating is pulled up, the descending speed is 100mm/min, the glass substrate is soaked in the dispersion liquid for 30s, the ascending speed is 100mm/min, and then the single-layer ZnO coating film is obtained by pulling up for 2 times.

Comparative example 2

The preparation method of the single-layer ZnO coating film comprises the following steps:

s1, preparing the ZnO quantum dots by adopting a sol-gel method. A cylinder was used to measure 40ml of absolute ethanol, which was added to a conical flask, followed by 2.4g of zinc acetate dihydrate (Zn (AC)₂·2H₂O) is added into absolute ethyl alcohol, then the mixture is put into a water bath kettle with the temperature set to 60 ℃ to be stirred for 40-60min, and then the temperature of the water bath is adjusted to 30 ℃. After the temperature was decreased to 30 deg.C, a KOH ethanol solution (wherein KOH was 0.45g, and absolute ethanol was 20ml) was added. Stirring for several minutes until the mixed solution becomes clear. And adding a normal hexane solution with the volume being 3 times that of the clear solution, quickly generating white precipitate in the clear solution, standing for 10min, and centrifuging to obtain the ZnO quantum dots after the precipitate is completely finished. And dispersing the centrifuged ZnO quantum dots in absolute ethyl alcohol to prepare the clear ZnO quantum dot coating liquid. Wherein the concentration of the ZnO quantum dots is 0.5 mol/L.

S2, pulling and coating: the coating liquid of the ZnO quantum dots is used for coating on a cleaned glass substrate in a pulling coating mode. And (3) during film coating lifting, the descending speed is 100mm/min, the glass substrate is soaked in the dispersion liquid for 30s, the ascending speed is 100mm/min, and then the single-layer ZnO coating film is obtained by lifting and pulling for 3 times.

Example 1

ZnO-SiO₂The preparation method of the double-layer coating film comprises the following steps:

s1, preparing the ZnO quantum dots by adopting a sol-gel method: a cylinder was used to measure 40ml of absolute ethanol, which was added to a conical flask, followed by 2.4g of zinc acetate dihydrate (Zn (AC)₂·2H₂O) is added into absolute ethyl alcohol, then the mixture is put into a water bath kettle with the temperature set to 60 ℃ to be stirred for 40-60min, and then the temperature of the water bath is adjusted to 30 ℃. After the temperature was decreased to 30 deg.C, a KOH ethanol solution (wherein KOH was 0.45g, and absolute ethanol was 20ml) was added. Stirring for several minutes until the mixed solution becomes clear. And adding a normal hexane solution with the volume being 3 times that of the clear solution, quickly generating white precipitate in the clear solution, standing for 10min, and centrifuging to obtain the ZnO quantum dots after the precipitate is completely finished. Dispersing the centrifuged ZnO quantum dots in anhydrousAnd preparing clear ZnO quantum dot coating liquid in ethanol. Wherein the concentration of the ZnO quantum dots is 0.5 mol/L;

s2, pulling and coating: the coating liquid of the ZnO quantum dots is used for coating on a cleaned glass substrate in a pulling coating mode. When the coating is pulled up, the descending speed is 100mm/min, the glass substrate is soaked in the dispersion liquid for 30s, the ascending speed is 100mm/min, and then the single-layer ZnO coating film is obtained by pulling up for 2 times;

s3 preparation of basic SiO₂Sol: tetraethyl orthosilicate (TEOS) and absolute ethanol (EtOH) were mixed in a molar ratio of TEOS: EtOH ═ 1:10 and mixed and magnetically stirred at room temperature for 30min to obtain solution A. H is to be₂O, EtOH and NH₃·H₂O is H in a molar ratio₂O：EtOH：NH₃·H₂O is 5: 10: 0.4 and magnetically stir at room temperature for 3min to record as solution B. Then, the solution A is slowly added into the solution B with continuous stirring, wherein the molar ratio of substances of the mixed solution of the solution A and the solution B is TEOS: EtOH: h₂O：NH₃·H₂O is 1:20:5: 0.4. placing the mixed solution in a constant-temperature water bath kettle for magnetic stirring, setting the stirring speed to be 600r/min, setting the water bath temperature to be 30 ℃, and setting the reaction time to be 7 hours to obtain the alkaline SiO₂And (3) sol. Then aging for 5 days at room temperature;

s4, and plating alkaline SiO on the ZnO coating₂Coating: firstly, aging 5 days of alkaline SiO₂HNO for sol₃The pH value of the sol is adjusted to be weakly acidic. Then coating the glass slide coated with the ZnO coating in the sol, wherein the pulling condition is the same as the condition for coating the ZnO coating. After the film coating is finished, putting the film in an oven for drying to prepare ZnO-SiO₂A double-layer coated film.

Example 2

ZnO-SiO₂The preparation method of the double-layer coating film comprises the following steps:

s1, preparing the ZnO quantum dots by adopting a sol-gel method: a cylinder was used to measure 40ml of absolute ethanol, which was added to a conical flask, followed by 2.4g of zinc acetate dihydrate (Zn (AC)₂·2H₂O) is added into absolute ethyl alcohol, and then is put into a temperature settingStirring the mixture in a water bath kettle at the temperature of 60 ℃ for 40-60min, and then adjusting the temperature of the water bath to 30 ℃. After the temperature was decreased to 30 deg.C, a KOH ethanol solution (wherein KOH was 0.45g, and absolute ethanol was 20ml) was added. Stirring for several minutes until the mixed solution becomes clear. And adding a normal hexane solution with the volume being 3 times that of the clear solution, quickly generating white precipitate in the clear solution, standing for 10min, and centrifuging to obtain the ZnO quantum dots after the precipitate is completely finished. And dispersing the centrifuged ZnO quantum dots in absolute ethyl alcohol to prepare the clear ZnO quantum dot coating liquid. Wherein the concentration of the ZnO quantum dots is 0.5 mol/L;

s2, pulling and coating: the coating liquid of the ZnO quantum dots is used for coating on a cleaned glass substrate in a pulling coating mode. When the coating is pulled up, the descending speed is 100mm/min, the glass substrate is soaked in the dispersion liquid for 30s, the ascending speed is 100mm/min, and then the single-layer ZnO coating film is obtained by pulling up for 3 times;

s3, and then preparing the basic SiO₂Sol: tetraethyl orthosilicate (TEOS) and absolute ethanol (EtOH) were mixed in a molar ratio of TEOS: EtOH ═ 1:10 and mixed and magnetically stirred at room temperature for 30min to obtain solution A. H is to be₂O, EtOH and NH₃·H₂O is H in a molar ratio₂O：EtOH：NH₃·H₂O is 5: 10: 0.4 and magnetically stir at room temperature for 3min to record as solution B. Then, the solution A is slowly added into the solution B with continuous stirring, wherein the molar ratio of substances of the mixed solution of the solution A and the solution B is TEOS: EtOH: h₂O：NH₃·H₂O is 1:20:5: 0.4. placing the mixed solution in a constant-temperature water bath kettle for magnetic stirring, setting the stirring speed to be 600r/min, setting the water bath temperature to be 30 ℃, and setting the reaction time to be 7 hours to obtain the alkaline SiO₂And (3) sol. Then aging for 5 days at room temperature;

s4, and plating alkaline SiO on the ZnO coating₂Coating: firstly, aging 5 days of alkaline SiO₂HNO for sol₃The pH value of the sol is adjusted to be weakly acidic. Then coating the glass slide coated with the ZnO coating in the sol, wherein the pulling condition is the same as the condition for coating the ZnO coating. After the film coating is finished, the film is placed in an oven for drying to prepare ZnO-SiO₂A double-layer coated film.

The scanning SEM of the thin films of comparative example 1 and example 1 was performed, and the results are shown in fig. 1, and it can be seen from fig. 1 that: single layer SiO₂The thickness of the coating film is 170nm, ZnO-SiO₂The thickness of the double-layer film is 248 nm; single layer SiO₂Cracks appear on the surface of the coating film, and ZnO-SiO₂The surface cracks of the double-layer coating film disappear.

Testing of the Single-layer ZnO coating film of comparative example 1, ZnO-SiO prepared in example 1₂The transmittance of the double-layer coating film and the pure glass is shown in fig. 2, and the results are shown in fig. 2: when a ZnO coating is coated, the transmittance of the glass is reduced, and a SiO layer is coated on the ZnO coating₂The transmittance after the film is obviously improved.

Testing of the Single-layer ZnO coating film of comparative example 2, ZnO-SiO prepared in example 2₂The transmittance of the double-layer coating film and the pure glass is shown in fig. 3, and the results are shown in fig. 3: the results of FIG. 3 are similar to those of FIG. 2, in that the transmittance of the glass is reduced after the ZnO coating is applied, and a SiO layer is applied₂The transmittance is significantly improved.

Test example 2 ZnO-SiO₂The result of the emission peak of the double-layer coating film excited by 365nm light is shown in FIG. 4, and it can be seen from FIG. 4 that: ZnO-SiO₂The double-layer film can convert the light to emit light and convert ultraviolet light into visible light.

It should be understood by those skilled in the art that the foregoing is only illustrative of several embodiments of the invention, and not of all embodiments. It should be noted that many variations and modifications are possible to those skilled in the art, and all variations and modifications that do not depart from the gist of the invention are intended to be within the scope of the invention as defined in the appended claims.