High-transmittance anti-radiation uv-cut glass cover plate for space photovoltaic and preparation method thereof

Abstract

The application discloses a high-transmittance anti-radiation UV cut-off glass cover plate for space photovoltaics and a preparation method thereof, and belongs to the technical field of anti-radiation materials. The glass cover plate comprises a glass substrate and a composite film layer arranged on the surface of the glass substrate; the composite film layer is composed of a first SiO2 layer, a CeO2-doped Si3N4 layer and a second SiO2 layer which are sequentially stacked; wherein the doping proportion of CeO2 in the CeO2-doped Si3N4 layer is 35wt%-45wt%. The preparation method comprises sequentially depositing each layer on the glass substrate by a magnetron sputtering method. Through the three-layer film structure design, the UV absorption characteristics and the variable valence anti-radiation mechanism of the CeO2-doped Si3N4 material are utilized, the synergistic effect of strong UV cut-off, high visible light transmittance and excellent anti-radiation performance is realized, the film layer structure is simple, the process compatibility is good, and the glass cover plate is suitable for the field of space solar cells.

Description

Technical Field

[0001] This invention belongs to the field of radiation-resistant materials technology, and particularly relates to a high-transmittance radiation-resistant UV-blocking glass cover for space photovoltaics and its preparation method. Background Technology

[0002] Space solar cells are the primary energy supply device for spacecraft, and their performance and lifespan directly affect the reliability and service life of the spacecraft. The space environment contains high-energy electrons, protons, and ultraviolet radiation, which can severely damage solar cells, leading to a decrease in photoelectric conversion efficiency. Therefore, it is necessary to cover the surface of the solar cells with a protective glass cover to block harmful radiation.

[0003] In the existing technology, radiation-resistant glass covers for space applications mainly adopt the following technical solutions:

[0004] (1) Radiation-resistant glass: rare earth oxides such as CeO2 are doped into the glass body, utilizing Ce... 3+ / Ce 4+ Variable valence mechanisms suppress the formation of radiation color centers. For example, the radiation-resistant glass specified in GJB1976A-2021 "Specification for Radiation-Resistant Glass for Space Use" has a CeO2 content of 5.0±0.3 wt%. (2) Antireflective coating: A single or multiple antireflective coating is deposited on the glass surface to improve the transmittance of visible light. Commonly used materials are MgF2, SiO2, etc. (3) UV cut-off film: The UV cut-off is achieved by using an interference film system or an absorption film system to protect the battery from UV damage.

[0005] However, the aforementioned existing technologies still have the following drawbacks or limitations: (1) Single function: Existing technologies either only consider radiation resistance or only consider anti-reflection or UV cutoff, making it difficult to meet multiple performance requirements at the same time; (2) Insufficient UV cutoff effect: Traditional interference-type UV cutoff films typically have a transmittance of >10% at 300nm, which is insufficient to effectively block UV radiation; (3) Low visible light transmittance: Due to CeO2 doping, the visible light transmittance of radiation-resistant glass is reduced, usually <92%; (4) Complex membrane structure: Existing UV cut-off membranes require more than 5 layers, which are complex and costly. (5) Insufficient radiation resistance: Ordinary antireflective films have no radiation resistance design, and the light transmittance decreases significantly after irradiation.

[0006] Therefore, there is an urgent need for a multifunctional, UV-blocking, high visible light transmittance, simple film structure, and excellent radiation resistance glass cover. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to overcome the deficiencies and defects mentioned in the background art above, and to provide a high transmittance anti-radiation UV cut-off glass cover for space photovoltaics and its preparation method.

[0008] To solve the above-mentioned technical problems, the technical solution proposed by this invention is as follows: A high-transmittance, radiation-resistant UV-blocking glass cover for space photovoltaic applications includes: a glass substrate and a composite film layer disposed on the surface of the glass substrate; the composite film layer is composed of a first SiO2 layer, a CeO2-doped Si3N4 layer and a second SiO2 layer stacked sequentially; wherein the CeO2 doping ratio in the CeO2-doped Si3N4 layer is 35 wt%-45 wt%.

[0009] In the aforementioned high-transmittance, radiation-resistant UV-blocking glass cover for space photovoltaics, the thickness of the first SiO2 layer is 80-90 nm, the thickness of the CeO2-doped Si3N4 layer is 105-120 nm, the thickness of the second SiO2 layer is 80-90 nm, and the thickness of the glass substrate is 70-80 μm.

[0010] Furthermore, the CeO2 doping ratio in the CeO2-doped Si3N4 layer is 40 wt%.

[0011] Furthermore, the high-transmittance anti-radiation UV-blocking glass cover for space photovoltaics has a transmittance of ≤1% for 300 nm wavelength ultraviolet light and an average transmittance of ≥95% for 400-700 nm wavelength visible light.

[0012] Furthermore, the glass cover plate is subjected to 1 MeV electrons and 1×10 15 e / cm 2 After irradiation, its transmittance decreases by ≤0.8%.

[0013] Based on a general inventive concept, the present invention also provides a method for preparing a high-transmittance, radiation-resistant UV-blocking glass cover for space photovoltaic applications, comprising the following steps: S1. A first SiO2 layer is deposited on a glass substrate by magnetron sputtering. S2. A CeO2-doped Si3N4 layer is deposited on the first SiO2 layer by magnetron sputtering. S3. A second SiO2 layer is deposited on the CeO2-doped Si3N4 layer by magnetron sputtering.

[0014] The above-described preparation method further includes a magnetron sputtering method that is radio frequency direct sputtering, wherein: The target material for depositing the first and second SiO2 layers is a pure SiO2 target. The sputtering power is 100-200 W, the working gas is Ar gas with a flow rate of 30-50 sccm and a working pressure of 0.3-0.5 Pa. The substrate temperature is 200-300 ℃, the deposition rate is 1-2 nm / min, and the deposition time is 40-45 min. The target material for depositing the CeO2-doped Si3N4 layer is a CeO2-doped Si3N4 target with a CeO2 doping ratio of 35wt%-45wt%. The sputtering power is 150-250 W, the working gas is Ar with a flow rate of 30-50 sccm, the working pressure is 0.3-0.5 Pa, the substrate temperature is 250-350 ℃, the deposition rate is 1-1.5 nm / min, and the deposition time is 75-80 min.

[0015] Furthermore, the magnetron sputtering method is a combination of reactive sputtering and radio frequency sputtering, and the sputtering mode is bipolar pulse or radio frequency sputtering, wherein: The target material for depositing the first and second SiO2 layers is a pure Si target, the sputtering power is 100-200 W, the working gas is an Ar / O2 mixture, the Ar:O2 flow ratio (sccm:sccm) is 60:40~90:10, the total flow rate is 40-60 sccm, the working pressure is 0.3-0.5 Pa, the substrate temperature is 200-300 ℃, and the deposition rate is 2-3 nm / min. The target material for depositing CeO2-doped Si3N4 layer (2) is a CeO2-doped Si3N4 target. Radio frequency sputtering is used with a sputtering power of 150-250 W, a working gas of pure Ar with a total flow rate of 40-60 sccm, a working pressure of 0.3-0.5 Pa, a substrate temperature of 250-350 ℃, and a deposition rate of 1.5-2 nm / min.

[0016] Furthermore, before the magnetron sputtering deposition, the glass substrate is ultrasonically cleaned with acetone, ethanol, and deionized water for 10-20 minutes each.

[0017] Furthermore, during the deposition process, the vacuum level is reduced to a background vacuum of <5×10⁻⁶. -4 Pa.

[0018] The working principle of this invention is as follows: (1) Visible light antireflection principle: The three-layer LHL structure forms an antireflection film system; the first SiO2 layer and the third SiO2 layer are low refractive index layers (n≈1.46), and the middle CeO2-doped Si3N4 layer is a high refractive index layer (n≈2.25); by optimizing the film thickness, the reflected light in the visible light region undergoes destructive interference, thereby maximizing the transmittance.

[0019] (2) UV cutoff principle: On the one hand, CeO2-doped Si3N4 has a high extinction coefficient in the UV region (0.720~0.132 at 200 nm~0.132 at 300 nm), which strongly absorbs ultraviolet light; on the other hand, the film system is designed to form high reflectivity in the UV region, and the two work together to achieve strong UV cutoff.

[0020] (3) Radiation resistance principle: Doped CeO2 passes through Ce 3+ / Ce 4+ The valence mechanism traps electrons generated by high-energy electron irradiation (Ce 4+ + e - →Ce 3+ This prevents electrons from being captured by defect centers in the glass or film to form color centers, thereby maintaining the material's high light transmittance.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention utilizes the UV absorption characteristics and variable valence radiation resistance mechanism of CeO2-doped Si3N4 material through a three-layer film structure design to achieve a synergistic effect of strong UV cutoff, high visible light transmittance, and excellent radiation resistance. Moreover, the film structure is simple, has good process compatibility, and is suitable for the field of space solar cells.

[0022] 2. This invention employs a three-layer antireflective film structure with matching low-high-low refractive indices, which significantly reduces reflectivity through interference effects. Tests show that the average transmittance in the 400-700 nm visible light region can reach 96.02%, and the peak transmittance (at 550 nm) can reach 99.98%. Compared with existing radiation-resistant glass (transmittance <92%), the transmittance is increased by more than 4%, effectively improving the photoelectric conversion efficiency of solar cells.

[0023] 3. This invention utilizes the strong absorption characteristics of CeO2-doped Si3N4 material in the ultraviolet region, combined with the film interference enhancement effect, to achieve a superior cutoff function for ultraviolet light. Test results show that the transmittance at 300 nm wavelength can be as low as 0.00%, which is far superior to traditional interference-type UV cutoff films (300 nm transmittance is usually >10%), improving the cutoff effect by more than 10 times, and can more effectively protect the battery from ultraviolet radiation damage.

[0024] 4. This invention introduces CeO2 into the film layer, utilizing Ce... 3+ / Ce 4+ The variable valence mechanism captures free electrons generated by high-energy electron irradiation, effectively preventing the formation of color centers; after 1 MeV electrons, 1×10 15 e / cm 2After irradiation, the light transmittance decreases by ≤0.6%, which is better than the requirement of ≤0.8% in the GJB1976A-2021 standard, significantly improving the service life and optical stability of the glass cover in the space radiation environment.

[0025] 5. This invention requires only 3 thin films to simultaneously achieve the three functions of anti-reflection, UV blocking, and radiation protection, with a total thickness of approximately 283 nm. Compared with the complex film systems of 5 or more layers used in the prior art to achieve UV blocking, the structure of this invention is more streamlined, the process is simpler, production costs are significantly reduced, and product yield is improved.

[0026] 6. This invention adopts a mature magnetron sputtering process, which can be either radio frequency direct sputtering (using ceramic targets) or reactive sputtering (using metal targets to prepare SiO2), making the process route flexible; this process is highly compatible with existing photovoltaic glass coating production lines and can achieve large-scale production without major equipment modifications. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the structure of the high transmittance anti-radiation UV cut-off glass cover plate for space photovoltaics in an embodiment of the present invention; Figure 2 This is the transmittance curve of the high transmittance anti-radiation UV cutoff glass cover plate for space photovoltaics in Embodiment 1 of the present invention, which is UTG / SiO2 / 40%CeO2-Si3N4 / SiO2.

[0029] Legend: 1-First SiO2 layer; 2-CeO2-doped Si3N4 layer; 3-Second SiO2 layer; 4-Glass substrate. Detailed Implementation

[0030] To facilitate understanding of the present invention, the present invention will be described more fully and in detail below with reference to the accompanying drawings and preferred embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments.

[0031] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0032] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0033] Example 1 A high-transmittance, UV-resistant glass cover for space photovoltaic applications, such as Figure 1 As shown, it includes a first SiO2 layer 1 with a thickness of 85 nm, a CeO2-doped Si3N4 layer 2 with a thickness of 113 nm (doping amount 40 wt%), a second SiO2 layer 3 with a thickness of 85 nm, and a glass substrate 4 with a thickness of 75 μm.

[0034] This embodiment uses radio frequency direct sputtering equipment for film deposition, and includes the following steps: (1) Substrate cleaning: The ultra-white glass substrate was ultrasonically cleaned with acetone, ethanol and deionized water for 15 min each in sequence; Dry with nitrogen and place in the magnetron sputtering chamber; (2) Vacuuming: Vacuuming until the background vacuum is <5×10 -4 Pa; (3) Deposition of the first SiO2 layer: The target material is a pure SiO2 target, the sputtering method is radio frequency sputtering, the sputtering power is 150 W, the working gas is Ar gas, the flow rate is 40 sccm, the working pressure is 0.4 Pa, the substrate temperature is 250 ℃, the deposition rate is 1.5 nm / min, and the deposition time is about 45 min (thickness 85 nm). The first and third SiO2 layers are low refractive index layers (n≈1.46, see Table 1). Table 1: Optical constants of SiO2

[0035] (4) Deposition of CeO2-doped Si3N4 layer: The target material is 40 wt% CeO2-doped Si3N4 target material, the sputtering method is radio frequency sputtering, the sputtering power is 200 W, the working gas is pure Ar gas, the flow rate is 40 sccm, the working pressure is 0.4 Pa, the substrate temperature is 300 ℃, the deposition rate is 1.5 nm / min, and the deposition time is about 80 min (thickness 113 nm). The middle CeO2-doped Si3N4 layer is a high refractive index layer (n≈2.25, see Table 2); Table 2: Optical constants of 40 wt% CeO2-doped Si3N4

[0036] (5) Deposit the second SiO2 layer: parameters are the same as in step (3); (6) Cooling and removing: Allow the sample to cool naturally to room temperature and then remove it.

[0037] The product performance test data for this embodiment are shown in Table 3. Figure 2 The test results are shown in Table 4, where the film thickness is expressed as the first SiO2 layer / CeO2-doped Si3N4 layer / second SiO2 layer.

[0038] Depend on Figure 2 As can be seen, the product of this embodiment has light transmittance data in the range of 300 nm to 900 nm. Ultraviolet light with wavelengths below 320 nm is completely blocked, while at a wavelength of 375 nm, the transmittance is increased to nearly 100%. In the entire visible light range (400 nm-700 nm), the average transmittance is better than 96%.

[0039] Table 3: Product Performance Test Data from Example 1

[0040] Table 4: Data Comparison of Examples 1-3

[0041] Example 2 A high-transmittance, UV-resistant glass cover for space photovoltaic applications, such as Figure 1 As shown, the substrate includes a first SiO2 layer 1 with a thickness of 90 nm, a CeO2-doped Si3N4 layer 2 with a thickness of 120 nm (doping amount 35 wt%), a second SiO2 layer 3 with a thickness of 90 nm, and a glass substrate 4 with a thickness of 75 μm. The preparation method is the same as in Example 1.

[0042] The performance comparison results are shown in Table 4.

[0043] Example 3 A high-transmittance, UV-resistant glass cover for space photovoltaic applications, such as Figure 1 As shown, the substrate includes a first SiO2 layer 1 with a thickness of 80 nm, a CeO2-doped Si3N4 layer 2 with a thickness of 105 nm (doping amount 45 wt%), a second SiO2 layer 3 with a thickness of 80 nm, and a glass substrate 4 with a thickness of 75 μm. The preparation method is the same as in Example 1.

[0044] The performance comparison results are shown in Table 4.

[0045] As shown in Tables 3 and 4, the glass cover provided by this invention exhibits excellent performance in visible light transmittance, UV cutoff effect, and radiation resistance, and all indicators are superior to existing technical standards. Among them, Example 1 demonstrates the best overall performance.

[0046] Example 4 A high-transmittance, UV-resistant glass cover for space photovoltaic applications, such as Figure 1 As shown, it includes a first SiO2 layer 1 with a thickness of 85 nm, a CeO2-doped Si3N4 layer 2 with a thickness of 113 nm (doping amount 40 wt%), a second SiO2 layer 3 with a thickness of 85 nm, and a glass substrate 4 with a thickness of 75 μm.

[0047] This embodiment uses reactive sputtering equipment for film deposition, and includes the following steps: Steps (1)-(2): Same as in Example 1; (3) Deposition of the first SiO2 layer: The target material is a pure Si target, the sputtering method is radio frequency sputtering, the sputtering power is 150 W, the working gas is an Ar / O2 mixture, the Ar:O2 flow rate ratio is 60:40, the total flow rate is 50 sccm, the working pressure is 0.4 Pa, the substrate temperature is 250 ℃, and the deposition rate is 2.5 nm / min; Steps (4)-(6): Same as in Example 1.

[0048] The product performance test data for this embodiment is shown in Table 5. The test data comparison is shown in Table 6, where the film thickness is expressed as the first SiO2 layer / CeO2-doped Si3N4 layer / second SiO2 layer.

[0049] Table 5: Product Performance Test Data from Example 4

[0050] Table 6: Data Comparison of Examples 4-6

[0051] Example 5 A high-transmittance, UV-resistant glass cover for space photovoltaic applications, such as Figure 1 As shown, the substrate includes a first SiO2 layer 1 with a thickness of 90 nm, a CeO2-doped Si3N4 layer 2 with a thickness of 120 nm (doping amount of 35 wt%), a second SiO2 layer 3 with a thickness of 90 nm, and a glass substrate 4 with a thickness of 75 μm. The preparation method is the same as in Example 4.

[0052] The performance comparison results are shown in Table 6.

[0053] Example 6 A high-transmittance, UV-resistant glass cover for space photovoltaic applications, such as Figure 1As shown, the substrate includes a first SiO2 layer 1 with a thickness of 80 nm, a CeO2-doped Si3N4 layer 2 with a thickness of 105 nm (doping amount 45 wt%), a second SiO2 layer 3 with a thickness of 80 nm, and a glass substrate 4 with a thickness of 75 μm. The preparation method is the same as in Example 4.

[0054] The performance comparison results are shown in Table 6.

[0055] As shown in Tables 5 and 6, the glass cover plate provided by this invention exhibits excellent performance in visible light transmittance, UV cutoff effect, and radiation resistance, and all indicators are superior to existing technical standards. Among them, Example 4 shows the best overall performance. However, the performance differences among the groups are not significant.

[0056] Comparative Example 1 (Different Preparation Processes) This comparative example uses an electron beam evaporation process to prepare a glass cover plate with the same structure as in Example 1, using a bulk material of CeO2-doped Si3N4 (40 wt%) as the evaporation source.

[0057] The following limitations exist: (1) Poor uniformity of film layer during large-area deposition leads to poor consistency of product optical performance (such as transmittance); (2) The stability and repeatability of the process are difficult to meet the requirements of large-scale industrial production.

[0058] Comparative Example 2 (Different Doping Ratios) This comparative example is based on the preparation method of Example 1, only adjusting the doping ratio of CeO2 in the Si3N4 layer to 30 wt% (Comparative Example 2-1) or 50 wt% (Comparative Example 2-2).

[0059] Compared with Example 1 (doping ratio 40 wt%), the performance test results are shown in Table 7. The results show that when CeO2 is doped with 30%, the ultraviolet cutoff function is poor and the irradiation attenuation is >1%; while when CeO2 is doped with 50%, the visible light transmittance is less than 93%. Considering both visible light transmittance and ultraviolet cutoff function, the 40% doping amount has the best function.

[0060] Table 7: Data Comparison of Example 1 and Comparative Example 2

[0061] This comparative example shows that: (1) When the doping ratio is too low (30 wt%), the UV cutoff effect and radiation resistance are insufficient, making it difficult to meet the requirement of irradiation attenuation ≤0.8% in the GJB1976A-2021 standard; (2) When the doping ratio is too high (50 wt%), although the UV cutoff effect and radiation resistance are excellent, the visible light transmittance decreases significantly, which affects the photoelectric conversion efficiency of the solar cell.

[0062] In summary, compared with the above comparative examples, the embodiments of the present invention, by optimizing the film structure, preparation process and CeO2 doping ratio, can achieve the best balance between visible light transmittance, UV cutoff effect and radiation resistance, and also have excellent process compatibility and mass production feasibility.

Claims

1. A high-transmittance, UV-resistant glass cover for space photovoltaic applications, characterized in that, include: A glass substrate (4) and a composite film layer disposed on the surface of the glass substrate (4); the composite film layer is composed of a first SiO2 layer (1), a CeO2-doped Si3N4 layer (2) and a second SiO2 layer (3) stacked sequentially; wherein the doping ratio of CeO2 in the CeO2-doped Si3N4 layer (2) is 35 wt%-45 wt%.

2. The high-transmittance, radiation-resistant UV-blocking glass cover for space photovoltaic applications according to claim 1, characterized in that, The thickness of the first SiO2 layer (1) is 80-90 nm, the thickness of the CeO2-doped Si3N4 layer (2) is 105-120 nm, the thickness of the second SiO2 layer (3) is 80-90 nm, and the thickness of the glass substrate (4) is 70-80 μm.

3. The high-transmittance, radiation-resistant UV-blocking glass cover for space photovoltaic applications according to claim 1, characterized in that, The CeO2 doping ratio in the CeO2-doped Si3N4 layer (2) is 40 wt%.

4. The high-transmittance, radiation-resistant UV-blocking glass cover for space photovoltaic applications according to any one of claims 1-3, characterized in that, The high-transmittance anti-radiation UV-blocking glass cover for space photovoltaics has a transmittance of ≤1% for 300 nm wavelength ultraviolet light and an average transmittance of ≥95% for 400-700 nm wavelength visible light.

5. The high-transmittance, UV-resistant glass cover for space photovoltaic applications according to any one of claims 1-3, characterized in that, The glass cover plate is subjected to 1 MeV electrons and 1×10 15 e / cm 2 After irradiation, its transmittance decreases by ≤0.8%.

6. A method for preparing a high-transmittance, radiation-resistant UV-blocking glass cover for space photovoltaic applications as described in any one of claims 1-5, characterized in that, Includes the following steps: S1. A first SiO2 layer (1) is deposited on a glass substrate (4) by magnetron sputtering. S2. A CeO2-doped Si3N4 layer (2) is deposited on the first SiO2 layer (1) by magnetron sputtering. S3. A second SiO2 layer (3) is deposited on the CeO2-doped Si3N4 layer (2) by magnetron sputtering.

7. The preparation method according to claim 6, characterized in that, The magnetron sputtering method is radio frequency direct sputtering, wherein: The target material for depositing the first SiO2 layer (1) and the second SiO2 layer (3) is a pure SiO2 target, the sputtering power is 100-200 W, the working gas is Ar gas with a flow rate of 30-50 sccm, the working gas pressure is 0.3-0.5 Pa, the substrate temperature is 200-300 ℃, the deposition rate is 1-2 nm / min, and the deposition time is 40-45 min; The target material for depositing the CeO2-doped Si3N4 layer (2) is a CeO2-doped Si3N4 target, wherein the CeO2 doping ratio is 35 wt%-45 wt%, the sputtering power is 150-250 W, the working gas is Ar gas with a flow rate of 30-50 sccm, the working pressure is 0.3-0.5 Pa, the substrate temperature is 250-350 ℃, the deposition rate is 1-1.5 nm / min, and the deposition time is 75-80 min.

8. The preparation method according to claim 6, characterized in that, The magnetron sputtering method is reactive sputtering, and the sputtering mode is bipolar pulse or radio frequency sputtering, wherein: The target material for depositing the first SiO2 layer (1) and the second SiO2 layer (3) is a pure Si target, the sputtering power is 100-200 W, the working gas is an Ar / O2 mixture, the Ar:O2 flow ratio is 60:40~90:10, the total flow rate is 40-60 sccm, the working pressure is 0.3-0.5 Pa, the substrate temperature is 200-300 ℃, and the deposition rate is 2-3 nm / min; The target material for depositing CeO2-doped Si3N4 layer (2) is a CeO2-doped Si3N4 target. Radio frequency sputtering is used with a sputtering power of 150-250 W, a working gas of pure Ar with a total flow rate of 40-60 sccm, a working pressure of 0.3-0.5 Pa, a substrate temperature of 250-350℃, and a deposition rate of 1.5-2 nm / min.

9. The preparation method according to any one of claims 6-8, characterized in that, Before the magnetron sputtering deposition, the glass substrate is ultrasonically cleaned with acetone, ethanol and deionized water for 10-20 min each.

10. The preparation method according to any one of claims 6-8, characterized in that, During the deposition process, the vacuum level is reduced to a background vacuum of <5×10⁻⁶. -4 Pa.

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