Photovoltaic cover plate and preparation method and application thereof

Abstract

The invention relates to a photovoltaic cover plate and a preparation method thereof, the photovoltaic cover plate comprises a substrate and a film coating layer, the film coating layer comprises a first film coating layer and a second film coating layer which are sequentially laminated on the surface of the substrate; the first coating layer is an amorphous carbon film layer with a diamond-like structure, and the second coating layer is a nano hydrophobic film layer containing fluorinated groups. The prepared photovoltaic cover plate film layer is high in hardness, good in friction resistance, small in surface energy, large in contact angle and good in light transmission, and a photovoltaic module comprising the prepared photovoltaic cover plate can keep stable power generation power and good safety and stability when being applied to the photovoltaic field of special severe environments such as the sea; on the other hand, preparation of the first film coating layer and the second film coating layer is achieved by switching the potential of the substrate end in the preparation process, alternate film coating is not needed, the prepared product is more compact in structure and good in light transmission, and the process complexity is low.

Description

Technical Field

[0001] The present invention relates to the field of photovoltaic cover plates, and in particular to a photovoltaic cover plate and a preparation method and use thereof. Background Art

[0002] Offshore photovoltaics is an effective way to deal with the contradiction between photovoltaic development and land resources, but unlike the relatively mature land photovoltaic technology, offshore photovoltaic technology is still in its infancy. Facing harsh sea conditions such as cyclic loads in waves, wind and currents, salt spray environment at sea, and easy accumulation of biological fouling, the power generation, safety and stability of photovoltaic modules have been seriously affected, thereby increasing the operation and maintenance burden and the risk of photovoltaic modules in offshore applications.

[0003] Photovoltaic cover plays an important role in the structure of photovoltaic modules. CN101950766A discloses a traditional land photovoltaic cover glass technology, which can be used for centralized, distributed and BIPV building photovoltaics, etc., and can protect the internal battery components from mechanical, water vapor, oxidation and aging resistance, but it is not adaptable enough to the continuous seawater and sediment scouring and marine microbial environment in the field of offshore photovoltaic applications, and cannot take into account the light transmittance, low friction coefficient and wear resistance required for offshore photovoltaic applications. Summary of the invention

[0004] The purpose of the present invention is to provide a photovoltaic module and a preparation method and use thereof. The photovoltaic cover plate prepared by the present invention has a low friction coefficient, high hardness and good friction resistance, as well as a small surface energy, a large contact angle and good light transmittance. The photovoltaic module including the photovoltaic cover plate prepared by the present invention can maintain stable power generation, good safety and stability when used in the offshore photovoltaic field.

[0005] In order to achieve the above-mentioned object, the present invention provides a photovoltaic cover plate in a first aspect, comprising a substrate and a coating layer, wherein the coating layer comprises a first coating layer and a second coating layer sequentially stacked on the surface of the substrate;

[0006] The first coating layer is an amorphous carbon film layer with a diamond-like structure, and the second coating layer is a nano-hydrophobic film layer containing fluorinated groups.

[0007] Optionally, the material of the substrate is selected from one or more of low-iron rolled glass, chemically tempered glass, anti-reflection coated glass, ethylene-tetrafluoroethylene copolymer and ethylene-chlorotrifluoroethylene copolymer;

[0008] Optionally, the coating layer comprises sp 3 Hybridized bonds and sp 2 Hybrid bond; wherein the sp 3 Hybridized bonds and sp2 The total molar content of the hybrid bonds is taken as the basis, and the sp 3 The molar content of the hybrid bond is 30 to 62%, based on the sp 3 The total molar content of carbon-carbon bonds and carbon-hydrogen bonds in the hybrid bonds is taken as the basis, and the sp 3 The molar content of carbon-carbon bonds in hybrid bonds is 70-82%;

[0009] The fluorinated groups include CF, CF2 and CF3;

[0010] Among them, the carbon-fluorine bonds, sp 3 Hybridized bonds and sp 2 The molar content of the fluorocarbon groups is 22-40% based on the total molar content of the hybrid bonds.

[0011] Optionally, the thickness of the first coating layer is 4 to 30 nm, preferably 4 to 10 nm; the thickness of the second coating layer is 2 to 10 nm, preferably 2 to 5 nm.

[0012] Optionally, the transmittance of the photovoltaic cover plate is 80-92%.

[0013] A second aspect of the present invention provides a photovoltaic module, wherein the photovoltaic module comprises a back sheet, a first adhesive film, a battery material, a second adhesive film and the photovoltaic cover sheet according to the first aspect of the present invention, which are stacked in sequence.

[0014] The third aspect of the present invention provides a method for preparing the photovoltaic cover plate according to the first aspect of the present invention, wherein the method comprises:

[0015] The first coating layer and the second coating layer are sequentially formed on the surface of the substrate by plasma enhanced chemical vapor deposition.

[0016] Optionally, the substrate is at a negative potential when the first coating layer is prepared, and the substrate is at a zero potential when the second coating layer is prepared.

[0017] Optionally, the conditions for depositing the first coating layer include: the reaction gas is a hydrocarbon gas, preferably one or more of methane, acetylene and butane; the gas flow rate is 5 to 30 sccm; the automatic pressure controller adjusts the gas pressure range to 0.13 to 10 Pa; the RF power supply power is 100 to 600 W; the chamber back vacuum is better than 2×10 -3 Pa;

[0018] The conditions for depositing the second coating layer include: the reaction gas is a mixture of carbon tetrafluoride gas and the hydrocarbon gas; the volume ratio of carbon tetrafluoride gas to the mixed gas is (0.25-1):1, preferably (0.45-0.55):1; the gas flow rate is 10-50 sccm; the automatic pressure controller adjusts the gas pressure range to 0.3-10 Pa; the radio frequency power supply power is 100-600 W; the chamber back vacuum is better than 2×10 -3 Pa;

[0019] The purity of the hydrocarbon gas is above 99.99%, and the purity of the carbon tetrafluoride gas is above 99.99%.

[0020] The fourth aspect of the present invention provides the use of the photovoltaic cover plate described in the first aspect of the present invention in offshore photovoltaics, desert photovoltaics, Gobi photovoltaics and desert photovoltaics.

[0021] Through the above technical solution, the present invention provides a coating layer containing sp in the photovoltaic cover plate. 3 Hybridized bonds and sp 2 The first coating layer of the diamond-like structure of the hybrid bond is beneficial to improving the hardness and wear resistance of the film layer as well as the light transmittance of the film layer; the second coating layer containing the fluorinated group is beneficial to improving the hydrophobicity of the film layer, so that the photovoltaic cover plate has a low friction coefficient, high hardness and good friction resistance, and at the same time has a small surface energy, a large contact angle and good light transmittance, so that the photovoltaic module assembled using the photovoltaic cover plate having the film layer structure of the present invention, and the photovoltaic module including the photovoltaic cover plate prepared by the present invention can maintain stable power generation, good safety and stability when used in the offshore photovoltaic field.

[0022] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present invention but do not constitute a limitation of the present invention. In the accompanying drawings:

[0024] Figure 1 This is a schematic structural diagram of the photovoltaic cover plate prepared in Example 1 of the present invention.

[0025] Figure 2 This is a schematic diagram of the structure of the photovoltaic module prepared in Example 1 of the present invention.

[0026] Figure 3 Schematic diagram of the process for preparing Example 1 of the present invention, wherein (a) is a schematic diagram of the process for preparing the first coating layer; and (b) is a schematic diagram of the process for preparing the second coating layer.

[0027] Figure 4 is the surface roughness of the photovoltaic cover plate, wherein (a) is the surface roughness of the photovoltaic cover plate prepared in Comparative Example 1 of the present invention; (b) is the surface roughness of the photovoltaic cover plate prepared in Example 1 of the present invention.

[0028] Figure 5 are SEM images of photovoltaic cover plates, wherein (a) is a SEM image of the photovoltaic cover plate prepared in comparative example 1 of the present invention after friction; (b) is a SEM image of the photovoltaic cover plate prepared in example 1 of the present invention after friction.

[0029] Description of Reference Numerals

[0030] 1. Photovoltaic cover plate; 2. First adhesive film; 3. Solar cell; 4. Second adhesive film; 5. Back plate.

[0031] 11. Photovoltaic cover substrate; 12. First coating layer; 13. Second coating layer.

[0032] S1, air inlet; S2, gas distribution plate; S3, vacuum chamber; S4, shielding cover; S5, substrate; S6, substrate table; S7, RF power supply; S8, matching device; S9, grounding terminal; S10, air outlet; S11, negative potential terminal. DETAILED DESCRIPTION

[0033] The specific implementation of the present disclosure is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the present disclosure, and is not used to limit the present disclosure.

[0034] A first aspect of the present disclosure provides a photovoltaic cover plate, comprising a substrate and a coating layer, wherein the coating layer comprises a first coating layer and a second coating layer sequentially stacked on the surface of the substrate;

[0035] The first coating layer is an amorphous carbon film layer with a diamond-like structure, and the second coating layer is a nano-hydrophobic film layer containing fluorinated groups.

[0036] In the present invention, the photovoltaic cover plate prepared by the present invention has a low friction coefficient, high hardness and good friction resistance, and at the same time has a small surface energy, a large contact angle and good light transmittance.

[0037] In a specific embodiment of the present invention, the material of the photovoltaic cover plate is one or more of low-iron rolled glass, chemically tempered glass, anti-reflective coated glass, ethylene-tetrafluoroethylene copolymer and ethylene-chlorotrifluoroethylene copolymer, preferably low-iron rolled glass;

[0038] In the above-mentioned embodiment, the low-iron rolled glass is prepared through the process steps of melt mixing, melting, rolling, annealing, cutting, coating, tempering and the like.

[0039] In a specific embodiment of the present invention, the coating layer comprises sp 3 Hybridized bonds and sp 2 Hybrid bond; sp in the coating layer 3 Hybridized bonds and sp 2 The total molar content of the hybrid bonds is taken as the basis, and the sp 3 The molar content of the hybrid bond is 35 to 62%, preferably 40 to 62%, based on the sp 3 The total molar content of carbon-carbon bonds and carbon-hydrogen bonds in the hybrid bonds is taken as the basis, and the sp 3 The molar content of carbon-carbon bonds in the hybrid bonds is 70 to 82%, preferably 75 to 82%;

[0040] In the above embodiment, sp 3 Hybrid bonds contain CC sp 3 Hybrid bonds and CH sp 3 Hybrid bonds, among which high content of CC sp 3 Hybrid bonds are beneficial to improving the hardness and wear resistance of the film. 3 Hybrid bonds are beneficial to improving the light transmittance of the film; on the other hand, sp 2 Hybrid bonds give the photovoltaic cover plate surface the advantages of low friction coefficient and small surface roughness, which can make the photovoltaic module resistant to microbial erosion. 3 Hybridized bonds and sp 2 When the content ratio of the hybrid bonds is within the preferred range of the present invention, the hardness, wear resistance and light transmittance of the prepared photovoltaic cover plate can be further improved.

[0041] In one embodiment of the present invention, the fluorinated group comprises CF, CF2 and CF3;

[0042] Among them, the carbon-fluorine bonds, sp 3 Hybridized bonds and sp 2 Based on the total molar content of the hybrid bonds, the molar content of the carbon-fluorine bonds is 22 to 40%, preferably 30 to 40%.

[0043] In the above embodiment, the presence of carbon-fluorine bonds makes the surface of the photovoltaic cover plate have good hydrophobicity. When seawater washes the photovoltaic module, the liquid still gathers into a sphere. After the next wave hits, the droplets roll and are carried away instead of spreading on the glass surface. This is beneficial for the photovoltaic module to resist seawater washing and has better safety and stability.

[0044] In a specific embodiment of the present invention, the thickness of the first coating layer is 4 to 30 nm, preferably 4 to 10 nm; the thickness of the second coating layer is 2 to 10 nm, preferably 2 to 5 nm.

[0045] In a specific embodiment of the present invention, the transmittance of the photovoltaic cover plate is 80-92%, preferably 90-92%.

[0046] In the above-mentioned embodiment, the photovoltaic cover plate having the film layer structure of the present invention has high transmittance, and the photovoltaic module including the photovoltaic cover plate prepared by the present invention can maintain stable power generation under long-term sunlight irradiation conditions and operate safely for a long time.

[0047] A second aspect of the present disclosure provides a photovoltaic module, wherein the photovoltaic module comprises a back sheet, a first adhesive film, a battery material, a second adhesive film and the photovoltaic cover sheet according to the first aspect of the present disclosure, which are stacked in sequence.

[0048] The photovoltaic module including the photovoltaic cover plate prepared by the present invention can maintain stable power generation, good safety and stability when used in photovoltaic fields in special harsh environments such as offshore photovoltaics, desert photovoltaics, Gobi photovoltaics and desert photovoltaics.

[0049] The third aspect of the present disclosure provides a method for preparing the photovoltaic cover plate according to the first aspect of the present disclosure, wherein the method comprises:

[0050] The first coating layer and the second coating layer are sequentially formed on the surface of the substrate by plasma enhanced chemical vapor deposition.

[0051] The present invention adopts plasma enhanced chemical vapor deposition to deposit the film layer, thus avoiding the problems of high input energy and carbon conduction sparking when preparing the carbon film by magnetron sputtering, and reducing the cost of the preparation process.

[0052] In a specific embodiment of the present invention, the photovoltaic cover substrate is at a negative potential when the first coating layer is prepared, and the photovoltaic cover substrate is at a zero potential when the second coating layer is prepared.

[0053] In the above embodiment, when depositing the first coating layer, the substrate is placed at a negative potential end, so that when the positive ions in the plasma atmosphere bombard the substrate, a certain amount of energy is supplied to the substrate, so that the CC sp 3 The hybrid bond content is higher and the structure is denser, which is beneficial to improving the hardness and wear resistance of the film layer; when preparing the second coating layer, switching the substrate to the zero potential end is beneficial to increasing the deposition rate of the carbon fluoride group, increasing the carbon fluoride group content, and improving the hydrophobicity of the photovoltaic cover surface. The preparation of the first coating layer and the second coating layer is achieved by switching the potential at the substrate end, without the need for alternating coating, and the process complexity is low.

[0054] In a specific embodiment of the present invention, the conditions for depositing the first coating layer include: the reaction gas is a hydrocarbon gas, preferably one or more of methane, acetylene and butane, more preferably high-purity methane gas; the gas flow rate is 5 to 30 sccm, preferably 5 to 15 sccm; the automatic pressure controller adjusts the gas pressure range to 0.13 to 10 Pa, preferably 0.13 to 1 Pa; the RF power is 100 to 600 W, preferably 100 to 300 W; the chamber back vacuum is better than 2×10 -3 Pa, preferably better than 2×10 -4 Pa;

[0055] The conditions for depositing the second coating layer include: the reaction gas is a mixed gas of carbon tetrafluoride gas and the hydrocarbon gas; the volume ratio of carbon tetrafluoride gas to the mixed gas is (0.25-1):1, preferably (0.45-0.55):1, and more preferably 0.5:1; the gas flow rate is 10-50sccm, preferably 10-30sccm; the automatic pressure controller adjusts the gas pressure range to 0.3-10Pa, preferably 0.3-1Pa; the radio frequency power is 100-600W, preferably 200-400W; the chamber back vacuum is better than 2×10 -3 Pa, preferably better than 2×10 -4 Pa;

[0056] The purity of the hydrocarbon gas is above 99.99%, preferably above 99.999%; the purity of the carbon tetrafluoride gas is above 99.99%, preferably above 99.999%.

[0057] The fourth aspect of the present disclosure provides the use of the photovoltaic cover plate described in the first aspect of the present disclosure in offshore photovoltaics, desert photovoltaics, Gobi photovoltaics and desert photovoltaics.

[0058] The present invention is further illustrated by the following examples, but the present invention is not limited thereto.

[0059] Example 1

[0060] a. Through the process steps of melt mixing, melting, rolling, annealing, cutting, coating, tempering, etc., a low-iron ultra-white rolled photovoltaic cover glass substrate is obtained, and then it is transferred to a plasma enhanced chemical vapor deposition (PECVD) device on an automatic transmission line for standby use;

[0061] b. Connect the photovoltaic cover glass substrate of step a to a radio frequency power supply. Due to the electrode self-bias effect, a negative potential is generated at the substrate end. Vacuum treatment is performed. The vacuum degree is 2×10 -4Pa, high-purity methane gas is introduced with a gas flow rate of 10 sccm, and the gas pressure range is adjusted to 0.3 Pa by an automatic pressure controller. After the pressure stabilizes, the RF power supply is turned on with a power of 200 W, and the first coating layer is deposited on the ultra-clear photovoltaic cover glass. The deposition time is 80 seconds and the thickness is 8 nm;

[0062] c. Change the potential access mode in the device of step b, connect the ultra-clear photovoltaic cover glass substrate to the ground terminal (i.e., zero potential), and perform vacuum treatment with a vacuum degree of 2×10 -4 Pa, a mixed gas of high-purity carbon tetrafluoride and methane is introduced, wherein the gas flow rate of CF4 is 10sccm and the gas flow rate of CH4 is 10sccm, and the gas pressure range is adjusted to 0.5Pa by an automatic pressure controller. After the pressure is stable, the RF power supply is turned on with a power of 300W, and a second coating layer is deposited on the first coating layer for 120 seconds with a thickness of 4nm;

[0063] d. Arrange and assemble the back plate, adhesive film, battery materials interconnected in a certain manner, adhesive film and the cover plate prepared by the method from bottom to top, and package them into photovoltaic modules using a lamination process.

[0064] Example 2

[0065] The method of Example 1 is adopted, the only difference is that in step c, the volume ratio of CF4 gas to CH4 gas is 3:1, wherein the gas flow rate of CF4 is 15 sccm, and the gas flow rate of CH4 is 5 sccm.

[0066] Example 3

[0067] The method of Example 1 is adopted, except that the deposition time of the first coating layer is 100 seconds, the thickness is 15 nm, and the deposition time of the second coating layer is 150 seconds, the thickness is 8 nm.

[0068] Example 4

[0069] The method of Example 1 is adopted, the only difference being that in step c, the potential of the photovoltaic cover substrate is not switched, wherein the substrate end is at zero potential in both step b and step c.

[0070] Comparative Example 1

[0071] Conventional photovoltaic cover glass is prepared through a series of process steps including melt mixing, melting, rolling, annealing, cutting, coating and tempering.

[0072] Test Case

[0073] The photovoltaic covers prepared in Examples 1 to 4 and Comparative Example 1 and the photovoltaic modules assembled using the photovoltaic covers were tested as follows:

[0074] The surface hardness of the film layer was tested by NNMT micro-nano mechanical properties testing system (Agilent Nano Indenter G200 from CSM, Switzerland).

[0075] The wear scar width of the film layer was tested by a friction and wear tester (HSR-2M high-speed reciprocating friction and wear tester, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences). The specific steps were as follows: a linear reciprocating mode was used, the wear object was a SiN hard ball with a diameter of φ4, the load was 0.49N, there was no lubrication, the stroke was 7mm, and the speed was 50rpm.

[0076] The surface morphology of the film layer was observed by atomic force microscopy (Agilent 5500, Veeco) and the surface roughness Ra was calculated.

[0077] The static contact angle between the film surface and water was tested by a contact angle tester (KRUSS DSA100, Germany), and the measurement method adopted was the angle measurement method.

[0078] The molar contents of groups and hybrid bonds were determined by Raman spectroscopy (HR800 microscopic laser Raman spectrometer from JY Company, France) with an excitation wavelength of 532 nm and a power of 0.1 mW.

[0079] Table 1

[0080]

[0081] According to the test results in Table 1, it can be seen that the photovoltaic cover prepared by the preparation method provided by the present invention is CC sp 3 A high content of hybrid bonds is beneficial to improving the hardness of the film layer, making the film layer have better friction resistance. At the same time, it has a small surface energy, a large contact angle, and good light transmittance. It can maintain stable power generation, good safety and stability when used in photovoltaic fields in special harsh environments such as sea and desert.

[0082] It can be seen from the test results of Examples 1 to 4 that when the preparation method and the film structure are within the specified range of the present invention, the effect and performance of the product prepared by the present invention can be improved. By comparing Example 1 with Examples 2 to 4, it can be seen that when the type and content of the groups in the film layer, the thickness of the film layer, and the coating process method and process parameters are all within the preferred specified range of the present invention, the hardness, light transmittance and wear resistance of the photovoltaic cover plate prepared by the present invention can be further improved; by comparing the test results of Example 1 with Example 4, it can be seen that switching the potential of the photovoltaic cover plate substrate during the coating process can improve the sp 3 The content of hybrid bonds makes the prepared film layer structure more compact, so that the prepared film layer has a smaller friction coefficient, higher hardness and better friction resistance.

[0083] From the test results of Comparative Example 1, it can be seen that the photovoltaic cover plate in Comparative Example 1 does not contain the film layer structure of the present invention, which will result in the prepared photovoltaic cover plate having a low friction coefficient, hardness and contact angle, a large surface roughness, a large wear mark width after friction, and the product quality and performance are significantly worse than those of Examples 1 to 4.

[0084] The preferred embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0085] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0086] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A photovoltaic cover plate, wherein: It comprises a substrate and a coating layer, wherein the coating layer comprises a first coating layer and a second coating layer which are sequentially stacked on the surface of the substrate; The first coating layer is an amorphous carbon film layer with a diamond-like structure, and the second coating layer is a nano-hydrophobic film layer containing fluorinated groups.

2. The photovoltaic cover plate according to claim 1, wherein: The material of the substrate is selected from one or more of low-iron rolled glass, chemically tempered glass, anti-reflection coated glass, ethylene-tetrafluoroethylene copolymer and ethylene-chlorotrifluoroethylene copolymer.

3. The photovoltaic cover plate according to claim 1, wherein: The coating layer contains sp 3 Hybridized bonds and sp 2 Hybrid bond; sp in the coating layer 3 Hybridized bonds and sp 2 The total molar content of the hybrid bonds is taken as the basis, and the sp 3 The molar content of the hybrid bond is 35 to 62%; 3 The total molar content of carbon-carbon bonds and carbon-hydrogen bonds in the hybrid bonds is taken as the basis, and the sp 3 The molar content of carbon-carbon bonds in hybrid bonds is 70-82%; The fluorinated groups include CF, CF2 and CF3; Among them, the carbon-fluorine bonds, sp 3 Hybridized bonds and sp 2 The molar content of the carbon-fluorine bond is 22-40% based on the total molar content of the hybrid bond.

4. The photovoltaic cover plate according to claim 1, wherein: The thickness of the first coating layer is 4-30 nm, preferably 4-10 nm; the thickness of the second coating layer is 2-10 nm, preferably 2-5 nm.

5. The photovoltaic cover plate according to claim 1, wherein: The transmittance of the photovoltaic cover plate is 80-92%.

6. A photovoltaic module, wherein: The photovoltaic module comprises a back sheet, a first adhesive film, a battery material, a second adhesive film and the photovoltaic cover sheet according to any one of claims 1 to 5 which are stacked in sequence.

7. A method for preparing a photovoltaic cover sheet according to any one of claims 1 to 5, wherein: The method includes: The first coating layer and the second coating layer are sequentially formed on the surface of the substrate by plasma enhanced chemical vapor deposition.

8. The method according to claim 7, wherein: When the first coating layer is prepared, the substrate is at a negative potential, and when the second coating layer is prepared, the substrate is at a zero potential.

9. The method according to claim 7, wherein: The conditions for depositing the first coating layer include: the reaction gas is a hydrocarbon gas, preferably one or more of methane, acetylene and butane; the gas flow rate is 5 to 30 sccm; the automatic pressure controller adjusts the gas pressure range to 0.13 to 10 Pa; the RF power supply power is 100 to 600 W; the chamber back vacuum is better than 2×10 - 3 Pa; The conditions for depositing the second coating layer include: the reaction gas is a mixture of carbon tetrafluoride gas and the hydrocarbon gas; the volume ratio of carbon tetrafluoride gas to the mixed gas is (0.25-1):1, preferably (0.45-0.55):1; the gas flow rate is 10-50 sccm; the automatic pressure controller adjusts the gas pressure range to 0.3-10 Pa; the radio frequency power supply power is 100-600 W; the chamber back vacuum is better than 2×10 -3 Pa; The purity of the hydrocarbon gas is above 99.99%, and the purity of the carbon tetrafluoride gas is above 99.99%.

10. Use of the photovoltaic cover plate according to any one of claims 1 to 5 in offshore photovoltaics, desert photovoltaics, Gobi photovoltaics and desert photovoltaics.

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