Radiation refrigeration product, radiation refrigeration film and preparation method of radiation refrigeration film

Abstract

The invention provides a radiation refrigeration product, a radiation refrigeration film and a preparation method of the radiation refrigeration film, the radiation refrigeration film comprises an emission layer and an anti-reflection layer which are sequentially stacked, in the visible light wavelength range, the effective refractive indexes of air, the anti-reflection layer and the emission layer are gradually increased, the emission layer and the anti-reflection layer are both made of light-transmitting materials, and the anti-reflection layer is of a porous structure. According to the radiation refrigeration film, the emission layer is arranged, so that the radiation refrigeration film has excellent emissivity in a middle infrared band and has high transmittance in a visible light band; the anti-reflection layer with the porous structure is arranged on one side of the emission layer, and the anti-reflection layer with the porous structure is matched with the emission layer to form the radiation refrigeration film with high emissivity and high transmittance in the visible light wavelength range.

Description

Technical Field

[0001] The present invention relates to the field of radiation refrigeration technology, and in particular to a radiation refrigeration product, a radiation refrigeration film and a preparation method thereof. Background Art

[0002] Radiative cooling is a green, environmentally friendly, energy-saving and efficient cooling technology. Without consuming energy, the energy of objects on Earth is transmitted to outer space through the "atmospheric window (8-13μm)" in the form of radiation, thereby achieving spontaneous cooling of the surface of objects. Currently, most radiative cooling materials are used in the textile and construction industries, without considering the transmittance of the materials in the visible light band, which limits the application of radiative cooling materials in optical windows. Summary of the invention

[0003] The main technical problem solved by the present invention is to provide a radiation cooling product, a radiation cooling film and a preparation method thereof, so as to solve the problem in the prior art that the transmittance in the visible light band is poor when the film layer has a high emissivity.

[0004] In order to solve the above technical problems, the first technical solution adopted by the present invention is: to provide a radiation cooling film, the radiation cooling film includes an emission layer and an anti-reflection layer stacked in sequence, in the visible light wavelength range, the effective refractive index of the air, the anti-reflection layer and the emission layer gradually increases, the emission layer and the anti-reflection layer are both made of light-transmitting materials, and the anti-reflection layer is a porous structure.

[0005] Wherein, the effective refractive index of the emitting layer is in the range of 2.30 to 2.60; and / or the effective refractive index of the anti-reflection layer is in the range of 1.18 to 1.30.

[0006] Wherein, the emission layer and the anti-reflection layer are both made of inorganic materials.

[0007] Wherein, the material of the emission layer is a combination of any two of silicon carbide, titanium dioxide and silicon nitride; and / or the material of the anti-reflection layer is any one of silicon dioxide and calcium fluoride.

[0008] Among them, the porosity of the anti-reflection layer is 39%~66%; the pore size of the anti-reflection layer is 50 nanometers~120 nanometers.

[0009] Wherein, the thickness of the anti-reflection layer is 100 nanometers to 200 nanometers; and / or the thickness of the emission layer is 400 nanometers to 500 nanometers.

[0010] In order to solve the above technical problems, the second technical solution adopted by the present invention is: to provide a method for preparing a radiation cooling film, the preparation method comprising: forming an emission layer; An anti-reflection layer with a porous structure is formed on one side of the emission layer; wherein, in the visible light wavelength range, the effective refractive indexes of the air, the anti-reflection layer and the emission layer gradually increase, and both the emission layer and the anti-reflection layer are made of light-transmitting materials.

[0011] The forming of the emission layer comprises: The emission layer is formed with the first inorganic material and the second inorganic material as raw materials; the first inorganic material and the second inorganic material are different, and the first inorganic material and the second inorganic material are any two of silicon carbide, titanium dioxide and silicon nitride.

[0012] The method of forming an emission layer using the first inorganic material and the second inorganic material as raw materials includes: The emission layer is formed by sputtering the first inorganic material and the second inorganic material as raw materials in a physical vapor deposition manner.

[0013] Wherein, the preparation method comprises: Obtaining a substrate; the substrate is a metal substrate, a plastic substrate, a building material substrate, a textile material substrate or a glass substrate; An emission layer is formed, comprising: An emission layer is formed on one side of the substrate.

[0014] Wherein, an anti-reflection layer with a porous structure is formed on one side of the emission layer, comprising: A prefabricated layer is formed on one side of the emission layer using a third inorganic material and a fourth inorganic material as raw materials; the third inorganic material and the fourth inorganic material are different; The fourth inorganic material in the prefabricated layer is removed, so that the third inorganic material forms an anti-reflection layer with a porous structure.

[0015] Wherein, the third inorganic material is any one of silicon dioxide and calcium fluoride; the fourth inorganic material is magnesium oxide; A prefabricated layer is formed on one side of the emission layer using the third inorganic material and the fourth inorganic material as raw materials, comprising: Sputtering a third inorganic material and a fourth inorganic material as raw materials on one side of the emission layer to form a prefabricated layer by physical vapor deposition; And / or, removing the fourth inorganic material in the prefabricated layer so that the third inorganic material forms an anti-reflection layer with a porous structure, comprising: The fourth inorganic material in the prefabricated layer is removed by chemical etching, so that the third inorganic material forms an anti-reflection layer with a porous structure.

[0016] In order to solve the above technical problems, the third technical solution adopted by the present invention is: to provide a radiation cooling product, the radiation cooling product includes a substrate and a radiation cooling film as mentioned above, the radiation cooling film is arranged on the substrate, and the emission layer of the radiation cooling film is in contact with the substrate.

[0017] The beneficial effects of the present invention are as follows: Different from the prior art, a radiation cooling product, a radiation cooling film and a preparation method thereof are provided, wherein the radiation cooling film comprises an emission layer and an anti-reflection layer stacked in sequence, and within the visible light wavelength range, the effective refractive indexes of the air, the anti-reflection layer and the emission layer gradually increase, and the emission layer and the anti-reflection layer are both made of light-transmitting materials, and the anti-reflection layer is a porous structure. The emission layer provided in the radiation cooling film of the present application enables the radiation cooling film to have excellent emissivity in the mid-infrared band and high transmittance in the visible light band; by providing an anti-reflection layer with a porous structure on one side of the emission layer, a radiation cooling film with high transmittance within the visible light wavelength range is formed by the anti-reflection layer with a porous structure cooperating with the emission layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0019] Figure 1 It is a schematic structural diagram of the radiation refrigeration product provided by the present invention; Figure 2 A comparison chart of the transparency of the original glass and the transparency of the coated glass provided by the present application; Figure 3 It is a schematic flow chart of an embodiment of a method for preparing a radiation cooling film provided by the present invention; Figure 4 It is a schematic structural diagram of a substrate in a radiation refrigeration product provided by the present invention; Figure 5 It is a schematic diagram of the structure of the radiation cooling product provided by the present invention, in which the substrate is covered with an emission layer; Figure 6 yes Figure 3 A schematic flow chart of a specific embodiment of step S2 in the method for preparing a radiant cooling film is provided; Figure 7 yes Figure 6 A structural schematic diagram corresponding to step S21 in the method for preparing a radiant cooling film provided in FIG.

[0020] In the figure: radiation cooling product 100; substrate 10; radiation cooling film 20; emission layer 201; anti-reflection layer 202; porous structure 2021; prefabricated layer 203. DETAILED DESCRIPTION

[0021] The scheme of the embodiment of the present application is described in detail below in conjunction with the drawings of the specification.

[0022] In the following description, for the purpose of explanation rather than limitation, specific details such as specific system structures, interfaces, and technologies are provided to facilitate a thorough understanding of the present application.

[0023] The term "and / or" in this article is only a description of the association relationship of the associated objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship. In addition, "many" in this article means two or more than two.

[0024] In order to enable those skilled in the art to better understand the technical solution of the present invention, a radiation cooling product, a radiation cooling film and a preparation method thereof provided by the present invention are further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein are only for the purpose of describing the embodiments of this application and are not intended to limit this application.

[0026] Before further describing the embodiments of the present application in detail, the nouns and terms involved in the embodiments of the present application are explained. The nouns and terms involved in the embodiments of the present application are subject to the following interpretations.

[0027] Physical Vapor Deposition (PVD) is a technology that uses physical methods to vaporize the surface of a material source into gaseous atoms or molecules, or partially ionize it into ions under vacuum conditions, and deposits a thin film with certain special functions on the surface of a substrate through a low-pressure gas (or plasma) process. PVD technology includes vacuum evaporation coating, vacuum sputtering coating, arc plasma coating, ion coating and molecular beam epitaxy (MBE).

[0028] Radiative cooling is a passive way of heat dissipation. It is a method of radiating heat in the form of electromagnetic waves through the "atmospheric transparent window (8-13μm)" to the outer space of the cold source to achieve the purpose of lowering the temperature. The whole process does not require any energy input, achieving true zero-carbon emissions. Radiative cooling needs to have a high emissivity and low absorptivity in the "atmospheric window" band. Radiative cooling technology can be widely used in building cooling, radiative cooling clothing fabrics, outdoor equipment heat dissipation, agricultural greenhouse cooling and other fields, and has a wide range of applications.

[0029] Currently, most radiation cooling materials are used in the textile and construction industries without considering the transmittance of the materials in the visible light band, which limits the application of radiation cooling materials in optical windows.

[0030] In order to improve the problem of poor transmittance of radiation cooling materials in the visible light band, some researchers have developed flexible transparent radiation cooling window materials. The radiation cooling materials are composed of multiple film layers. By adding a visible light transmittance-enhancing layer, the radiation cooling materials can achieve high transmittance in the visible light band and high reflection in the near infrared. Among them, the radiation cooling material is composed of multiple films, which are a mid-infrared emission layer, a near-infrared anti-reflection layer and a visible light transmittance-enhancing layer. Polydimethylsiloxane is used as the mid-infrared emission layer to achieve mid-infrared band emission, silver is used as the near-infrared anti-reflection layer to achieve reflection of the near-infrared 0.8μm-2.5μm solar spectrum, and polycarbonate is used as the visible light transmittance-enhancing layer. By constructing a polymer-metal-polymer structure, the functions of visible light transmission and near-infrared high reflection are achieved. However, the designed film system has an average transmittance of 0.6 in the visible light band of 0.4μm-0.8μm, and its transmittance is relatively low. Therefore, the application of this flexible transparent radiation cooling window material is limited in some high-transmittance demanding scenarios such as optical glass windows. In addition, the mid-infrared emission layer and the visible light transmittance enhancement layer use organic polymers, but organic materials are easily degraded, resulting in a decrease in the radiation cooling efficiency of the film layer, which limits its outdoor application.

[0031] Since the sum of the absorptivity, transmittance and reflectivity of a material is 1, the present application reduces the reflectivity of the radiation cooling material by introducing an anti-reflection layer, thereby increasing the transmittance of the radiation cooling material in the visible light band.

[0032] See also Figure 1 , Figure 1 It is a schematic structural diagram of the radiation refrigeration product provided by the present invention.

[0033] In this embodiment, a radiation cooling product 100 is provided, which includes a substrate 10 and a radiation cooling film 20, wherein the radiation cooling film 20 is disposed on the substrate 10. The radiation cooling film 20 includes an emission layer 201 and an anti-reflection layer 202 which are stacked in sequence. The emission layer 201 is in contact with the substrate 10, and the anti-reflection layer 202 is disposed on a surface of the emission layer 201 which is away from the substrate 10.

[0034] In one embodiment, the substrate 10 is a metal substrate, a plastic substrate, a building material substrate, a textile material substrate or a glass substrate. In the following embodiments, the substrate 10 is a glass substrate as an example for detailed description.

[0035] The emissive layer 201 has high emissivity in the mid-infrared wavelength range and high transmittance in the visible light wavelength range. The mid-infrared wavelength range is 0.8μm~2.5μm, and the visible light wavelength range is 0.4μm~0.8μm. Emissivity is a physical quantity that characterizes the ability of an object to emit infrared radiation, and its value range is from 0 to 100%, where 100% represents a completely black body that can emit 100% of its thermal radiation. Transmittance is usually expressed as a percentage, and its value range is between 0% and 100%, where 100% means that all incident light is completely transmitted by the material, and 0% means that no light is transmitted.

[0036] The anti-reflection layer 202 and the emission layer 201 are both made of inorganic materials. The radiation cooling film 20 made of inorganic materials can effectively improve the problem of easy aging and degradation of the existing radiation cooling film 20, and improve the bonding strength between the radiation cooling film 20 and the substrate 10, so that the radiation cooling film 20 is suitable for outdoor scenes, and the application range of the radiation cooling film 20 is expanded.

[0037] In the visible light wavelength range, the effective refractive index of air, anti-reflection layer 202 and emission layer 201 gradually increases. Both emission layer 201 and anti-reflection layer 202 are made of light-transmitting materials, and anti-reflection layer 202 is a porous structure 2021. The effective refractive index represents the ratio of the reflection of light on an object to the refractive index, and reflects the ability of the object to absorb, penetrate and scatter light. Among them, the effective refractive index of the glass substrate is 1.5. In this embodiment, by providing an anti-reflection layer with a porous structure, in the visible light range, the incident light is easily specularly reflected on the smooth surface. When the incident light is irradiated on the porous structure; the incident light may be reflected and scattered multiple times inside the porous structure, reducing the chance of direct reflection, and the porous structure will scatter the light into diffuse reflection, thereby reducing the total reflectivity and thus reducing the radiation cooling product 100.

[0038] In this embodiment, the gradient refractive index can reduce the number of scattering centers, thereby reducing scattering losses and improving the light transmittance of the material; and since light does not change suddenly at the interface between different refractive index regions, reflection losses are reduced and transmittance can be improved. Therefore, the anti-reflection layer 202 and the emission layer 201 are set to have different refractive indices, and in order to ensure that the effective refractive index of the anti-reflection layer 202 of the radiation cooling product 100 is as close to 2k+1 / 4λ as possible within the visible light wavelength range, the effective refractive index of the anti-reflection layer 202 should be as low as possible, so the effective refractive indices of air, the anti-reflection layer 202 and the emission layer 201 are set to increase gradually.

[0039] The effective refractive indexes of the emitting layer 201 and the anti-reflection layer 202 are respectively related to the effective refractive index of the glass substrate. The effective refractive indexes of the emitting layer 201 and the anti-reflection layer 202 arranged on different substrates 10 are all different.

[0040] In one embodiment, the effective refractive index of the emission layer 201 is in the range of 2.3 to 2.6. The effective refractive index of the emission layer 201 may be in the range of 2.35 to 2.57. Specifically, the effective refractive index of the emission layer 201 is 2.4, 2.43, 2.46, 2.50, 2.52, or 2.56.

[0041] In one embodiment, the material of the emission layer 201 is a combination of any two of silicon carbide, titanium dioxide, and silicon nitride. The effective refractive index of the emission layer 201 is determined based on the mass ratio of the two inorganic materials in the emission layer 201 and the refractive index of the inorganic materials. For example, when the material of the emission layer 201 includes the first inorganic material A and the second inorganic material B, the effective refractive index n of the emission layer 201 is 发射层 =n A *x+n B *(1-x), where x is the content of the first inorganic material A in the emission layer 201, n A is the refractive index of the first inorganic material A; n B is the refractive index of the second inorganic material B. The first inorganic material A is different from the second inorganic material B, thereby improving the phenomenon that the radiation cooling film 20 made of a single inorganic material is easily brittle.

[0042] In this embodiment, the emissivity of the emission layer 201 in the mid-infrared band can be adjusted by adjusting the ratio of the first inorganic material and the second inorganic material in the emission layer 201 .

[0043] The emission layer 201 provided in this embodiment is prepared by a physical vapor deposition process. Specifically, the emission layer 201 is prepared by a magnetron sputtering process. The emission layer 201 prepared by the physical vapor deposition process can improve the bonding force between the emission layer 201 and the substrate 10, which helps to improve the reliability of the radiation cooling product 100.

[0044] In one embodiment, the thickness of the emission layer 201 may be 400 nanometers to 500 nanometers. For example, the thickness of the emission layer 201 may be 400 nanometers, 410 nanometers, 420 nanometers, 430 nanometers, 440 nanometers, 450 nanometers, 460 nanometers, 470 nanometers, 480 nanometers, 490 nanometers, 500 nanometers, etc., and may be set according to actual conditions. In one embodiment, when the thickness of the emission layer is 450 nanometers, the transmittance of the manufactured radiation cooling product is optimal.

[0045] In one embodiment, the effective refractive index of the anti-reflection layer 202 is in the range of 1.18 to 1.30. The effective refractive index of the anti-reflection layer 202 may be in the range of 1.20 to 1.28. Specifically, the effective refractive index of the anti-reflection layer 202 is 1.22, 1.23, 1.24, 1.25, 1.26, 1.27, 1.28. Specifically, the effective refractive indexes of different emission layers and the transmittances corresponding to the effective refractive indexes of different anti-reflection layers are shown in Table 1.

[0046] Table 1

[0047] Because the optimal refractive index of the radiation cooling product 100 obtained by the square root of the product of the refractive index of the substrate 10 and the refractive index of the air should be 1.23. In order to improve the spectral band anti-reflection range and mid-infrared emissivity of the radiation cooling product 100, the emission layer 201 with a relatively high film thickness is introduced, and the emission layer 201 has a relatively high effective refractive index. Because the optical thickness of the radiation cooling product 100 is the film thickness*refractive index, in order to ensure that the effective refractive index of the anti-reflection layer of the radiation cooling product 100 is as close to 2k+1 / 4λ as possible within the visible light wavelength range, the refractive index of the anti-reflection layer should be as low as possible, but the low refractive index of the anti-reflection layer also represents an increase in porosity. Therefore, after comprehensive consideration, after calculation and adaptation, when the effective refractive index of the emission layer is 2.45 and the effective refractive index of the anti-reflection layer is 1.22, the light transmission effect of the radiation cooling product 100 is the best.

[0048] In one embodiment, the material of the anti-reflection layer 202 is silicon dioxide or calcium fluoride. The effective refractive index of the anti-reflection layer 202 is determined based on the refractive index and material ratio of the inorganic material constituting the emission layer 201. For example, the material of the anti-reflection layer 202 is the third inorganic material C, and the effective refractive index n of the anti-reflection layer 202 is 抗反射层 =n C *x+n 空气 *(1-x). Wherein, x is the content of the third inorganic material C in the anti-reflection layer 202. The third inorganic material may be the same as the first inorganic material or the second inorganic material, or may be different from the first inorganic material.

[0049] The anti-reflection layer 202 in this embodiment is prepared by a physical vapor deposition process and a chemical etching process, wherein the physical vapor deposition process may be a magnetron sputtering process.

[0050] By changing the effective refractive index of the emitting layer 201 and the anti-reflection layer 202, the effective refractive index of the emitting layer 201, the effective refractive index of the anti-reflection layer 202 and the effective refractive index of the substrate 10 satisfy (n 发射层 / n 抗反射层 ) 2 =n基材 *n 空气 This relationship can improve the transmittance of the radiation cooling product 100 in the visible light band.

[0051] In one embodiment, the thickness of the anti-reflection layer may be 100 nanometers to 200 nanometers. For example, the thickness of the emission layer 201 may be 100 nanometers, 110 nanometers, 120 nanometers, 130 nanometers, 140 nanometers, 150 nanometers, 160 nanometers, 170 nanometers, 180 nanometers, 190 nanometers, 200 nanometers, etc., and may be set according to actual conditions. In one embodiment, when the thickness of the anti-reflection layer is 130 nanometers, the transmittance of the manufactured radiation cooling product is optimal.

[0052] The porosity of the anti-reflection layer is 39% to 66%. For example, the porosity of the anti-reflection layer 202 can be 39%, 45%, 50%, 55%, 60%, 65%, etc., which is set according to actual conditions.

[0053] The pore size of the anti-reflection layer 202 is 50 nanometers to 120 nanometers. For example, the pore size of the anti-reflection layer 202 can be 50 nanometers, 60 nanometers, 70 nanometers, 80 nanometers, 90 nanometers, 100 nanometers, 110 nanometers, 115 nanometers, or 120 nanometers.

[0054] In this embodiment, the radiation cooling film 20 including the anti-reflection layer 202 and the emission layer 201 is prepared by physical vapor deposition process and chemical etching process. The radiation cooling film 20 has simple components and a simple preparation process, and is easy to be mass-produced and applied.

[0055] By adjusting the material ratio of the two inorganic materials forming the emission layer 201, the effective refractive index of the emission layer 201 is adjusted, thereby increasing the emissivity of the radiation cooling film 20 in the mid-infrared wavelength range; by adjusting the porosity of the porous structure 2021 in the anti-reflection layer 202, the effective refractive index of the anti-reflection layer 202 can be adjusted. By adjusting the relationship between the effective refractive index of the anti-reflection layer 202 and the effective refractive index of the emission layer 201, the transmittance of the radiation cooling film 20 in the visible light band is increased, the anti-reflection effect of the radiation cooling film 20 is achieved, and the applicable range of the radiation cooling film 20 is increased.

[0056] See also Figure 2 , Figure 2 A comparison chart of the transparency of original glass and the transparency of the coated glass provided in this application is provided.

[0057] In one embodiment, if Figure 2As shown, the original glass is formed by coating the radiation cooling material currently on the market on the glass; the coated glass is formed by coating the radiation cooling film 20 provided in this embodiment on the glass. When the visible light wavelength range is 450nm~600nm, the transparency of the original glass is about 92%; the transparency of the coated glass is increased to about 95%, which is 3% higher than that of the original glass, thereby increasing the application range of the radiation cooling film 20.

[0058] In the radiation cooling product 100 provided in this embodiment, the radiation cooling film 20 includes an emission layer 201 and an anti-reflection layer 202 which are stacked in sequence. In the visible light wavelength range, the effective refractive indexes of air, the anti-reflection layer 202 and the emission layer 201 gradually increase. The emission layer 201 and the anti-reflection layer 202 are both made of light-transmitting materials, and the anti-reflection layer 202 is a porous structure 2021. In the present application, an anti-reflection layer 202 having a porous structure 2021 is provided on one side of the emission layer 201, and the anti-reflection layer 202 having a porous structure 2021 cooperates with the emission layer 201 to form a radiation cooling film 20 with high transmittance in the visible light wavelength range.

[0059] See also Figure 3 , Figure 3 It is a schematic flow chart of an embodiment of a method for preparing a radiation cooling film provided by the present invention.

[0060] The present embodiment provides a method for preparing a radiation cooling film 20 , and the method for preparing the radiation cooling film 20 includes the following steps.

[0061] S1: forming an emission layer.

[0062] S2: An anti-reflection layer with a porous structure is formed on one side of the emission layer; wherein, in the visible light wavelength range, the effective refractive indexes of the air, the anti-reflection layer and the emission layer gradually increase, and the emission layer and the anti-reflection layer are both made of light-transmitting materials.

[0063] See also Figure 4 , Figure 4 It is a schematic structural diagram of a substrate in a radiation refrigeration product provided by the present invention.

[0064] In one embodiment, the method for preparing the radiative cooling film 20 further includes obtaining a substrate 10. The substrate 10 is a metal substrate, a plastic substrate, a building material substrate, a textile material substrate or a glass substrate. An emission layer 201 is formed on one side of the substrate 10. In the following embodiments, the substrate 10 is a glass substrate as an example for detailed description.

[0065] Specifically, the specific implementation of forming the emission layer 201 in step S1 is as follows.

[0066] In one embodiment, the emission layer 201 is formed using a first inorganic material and a second inorganic material as raw materials; the first inorganic material and the second inorganic material are different, and the first inorganic material and the second inorganic material are any two of silicon carbide, titanium dioxide and silicon nitride.

[0067] See also Figure 5 , Figure 5 It is a schematic diagram of the structure of the radiation cooling product provided by the present invention, in which the substrate is covered with an emission layer.

[0068] In a specific embodiment, the emission layer 201 is formed by sputtering the first inorganic material and the second inorganic material as raw materials in a physical vapor deposition manner.

[0069] Specifically, the glass substrate is pretreated, for example, the glass substrate is placed in an ethanol solution and subjected to ultrasound for 15 to 30 minutes, then the glass substrate is taken out and the surface of the glass substrate is blown dry with nitrogen to clean the surface of the glass substrate.

[0070] The pretreated glass substrate is placed in a magnetron device and the parameters of the magnetron device are set. For example, the magnetron device can be evacuated to a vacuum range of 3×10 -4 Pa~5×10 -4 Pa; the argon flow rate range can be set to 15mL / min-30mL / min; the working gas pressure range can be set to 0.6Pa~1.2Pa; the sputtering power range can be set to 80W~120W; the temperature range of the sample stage can be set to 200℃~400℃; the sputtering time range can be set to 3h~30h. In the magnetron device, target A and target B are co-sputtered to form the emission layer 201. Target A and target B are respectively any two of silicon carbide, titanium dioxide and silicon nitride. After the sputtering time is reached, target A and target B stop working.

[0071] Through the above steps, an emission layer 201 formed of the first inorganic material and the second inorganic material can be formed on the glass substrate.

[0072] In a specific embodiment, the glass substrate is placed in an ethanol solution and ultrasonicated for 20 minutes, after which the glass substrate is taken out and the surface of the glass substrate is blown dry with nitrogen to clean the surface of the glass substrate. The pretreated glass substrate is placed in a magnetron device and the magnetron device is evacuated to a vacuum degree of 4.5×10 -4 Pa; set the argon gas flow rate to 30 mL / min; set the working gas pressure to 1.0 Pa; set the sputtering power to 120 W; set the temperature of the sample stage to 200° C.; use target A and target B to co-sputter in the magnetron device to form the emission layer 201. Target A sputters silicon carbide, and target B sputters titanium dioxide.

[0073] In a specific embodiment, when target A is silicon carbide, the power of the RF power supply is 120W, the working pressure is 1.0Pa, the sputtering time is 18h, and the sample stage temperature is 200°C; when target B is titanium dioxide, the RF power supply is 120W, the working pressure is 1.0Pa, the sputtering time is 15h. The sample stage temperature is 200°C. In the magnetron device, target A and target B are co-sputtered to form the emission layer 201.

[0074] In a specific embodiment, when target A is silicon carbide, the power of the RF power supply is 120W, the working pressure is 1.0Pa, the sputtering time is 17h, and the sample stage temperature is 200° C.; when target B is silicon nitride, the RF power supply is 120W, the working pressure is 1.0Pa, the sputtering time is 23h, and the sample stage temperature is 200° C. In the magnetron device, target A and target B are co-sputtered to form the emission layer 201.

[0075] In a specific embodiment, when target A is titanium dioxide, the power of the RF power supply is 120 W, the working pressure is 1.0 Pa, the sputtering time is 15 hours, and the sample stage temperature is 200° C.; when target B is silicon nitride, the RF power supply is 120 W, the working pressure is 1.0 Pa, the sputtering time is 20 hours, and the sample stage temperature is 200° C. In the magnetron device, target A and target B are co-sputtered to form the emission layer 201.

[0076] Specifically, a specific implementation of forming the anti-reflection layer 202 having a porous structure 2021 on one side of the emission layer 201 in step S2 is as follows.

[0077] See also Figure 6 , Figure 6 yes Figure 3 A schematic flow chart of a specific embodiment of step S2 in a method for preparing a radiative cooling film is provided.

[0078] S21: forming a prefabricated layer on one side of the emission layer using a third inorganic material and a fourth inorganic material as raw materials; the third inorganic material and the fourth inorganic material are different.

[0079] Specifically, the third inorganic material is silicon dioxide; and the fourth inorganic material is magnesium oxide.

[0080] See also Figure 7 , Figure 7 yes Figure 6 A structural schematic diagram corresponding to step S21 in the method for preparing a radiant cooling film provided in FIG.

[0081] The prefabricated layer 203 is formed by sputtering the third inorganic material and the fourth inorganic material as raw materials on one side of the emission layer 201 in a physical vapor deposition manner.

[0082] In one embodiment, the emission layer 201 is further placed in a magnetron device, and the parameters of the magnetron device for forming the prefabricated layer 203 are the parameters for forming the emission layer 201 .

[0083] The magnetron device uses a C target and a D target to co-sputter to form a prefabricated layer 203. The C target sputters a third inorganic material, which is silicon dioxide. The D target sputters a fourth inorganic material, which is magnesium oxide. After the sputtering time is reached, the C target and the D target stop working.

[0084] Through the above steps, a prefabricated layer 203 formed of the third inorganic material and the fourth inorganic material may be formed on the anti-reflection layer 202 .

[0085] In a specific embodiment, the sputtering power of the magnetron device is set to 100W, and the parameters of other magnetron devices are consistent with the parameters for forming the emission layer 201. The A target and the B target of the magnetron device are turned off, and the C target and the D target are turned on. After the sputtering is completed, the prefabricated layer 203 is formed on the side of the emission layer 201 away from the glass substrate. Among them, the C target sputters silicon dioxide, and the D target sputters magnesium oxide.

[0086] In a specific embodiment, when target C is silicon dioxide, the power of the RF power supply is 100W, the working pressure is 1.0Pa, the sputtering time is 3h, and the sample stage temperature is 200°C; when target D is magnesium oxide, the RF power supply is 100W, the working pressure is 1.0Pa, and the sputtering time is 3h. Targets A and B of the above magnetron device are turned off, and targets C and D are turned on. After the sputtering is completed, a prefabricated layer 203 is formed on the side of the emission layer 201 away from the glass substrate.

[0087] In a specific embodiment, when target C is calcium fluoride, the power of the RF power source is 100W, the working pressure is 1.0Pa, the sputtering time is 3 hours, and the sample stage temperature is 200°C; target D is magnesium oxide, the RF power source is 100W, the working pressure is 1.0Pa, and the sputtering time is 3 hours. Targets A and B of the above magnetron device are turned off, and targets C and D are turned on. After the sputtering is completed, a prefabricated layer 203 is formed on the side of the emission layer 201 away from the glass substrate.

[0088] S22: removing the fourth inorganic material in the prefabricated layer, so that the third inorganic material forms an anti-reflection layer with a porous structure.

[0089] In one embodiment, if Figure 1 As shown, the fourth inorganic material in the prefabricated layer 203 is removed by chemical etching, so that the third inorganic material forms the anti-reflection layer 202 of the porous structure 2021 .

[0090] In a specific embodiment, hydrochloric acid is used to chemically etch the magnesium oxide in the prefabricated layer 203 to remove the magnesium oxide in the prefabricated layer 203. A porous structure 2021 is generated in the prefabricated layer 203 from which the magnesium oxide is removed, so that the prefabricated layer 203 forms an anti-reflection layer 202 of the porous structure 2021.

[0091] Through the above steps, a radiation cooling product 100 can be obtained, which is composed of a glass substrate, an emission layer 201 and an anti-reflection layer 202 stacked in sequence.

[0092] In the preparation method of the radiation cooling film 20 provided in the present embodiment, the emission layer 201 provided in the radiation cooling film 20 enables the radiation cooling film 20 to have excellent emissivity in the mid-infrared band and high transmittance in the visible light band; by providing an anti-reflection layer 202 with a porous structure 2021 on one side of the emission layer 201, the anti-reflection layer 202 with the porous structure 2021 cooperates with the emission layer 201 to form a radiation cooling film 20 with high emissivity in the mid-infrared wavelength range and high transmittance in the visible light wavelength range.

[0093] The above are only implementation modes of the present invention, and are not intended to limit the patent protection scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A radiation cooling film, characterized in that: The radiation cooling film includes an emission layer and an anti-reflection layer stacked in sequence. In the visible light wavelength range, the effective refractive indexes of air, the anti-reflection layer and the emission layer gradually increase. The emission layer and the anti-reflection layer are both made of light-transmitting materials, and the anti-reflection layer is a porous structure.

2. The radiative cooling film according to claim 1, characterized in that: The effective refractive index of the emitting layer is in the range of 2.30 to 2.60; and / or the effective refractive index of the anti-reflection layer is in the range of 1.18 to 1.

3.

3. The radiation cooling film according to claim 1, characterized in that: The emission layer and the anti-reflection layer are both made of inorganic materials.

4. The radiation cooling film according to claim 3, characterized in that: The material of the emission layer is a combination of any two of silicon carbide, titanium dioxide and silicon nitride; and / or the material of the anti-reflection layer is any one of silicon dioxide and calcium fluoride.

5. The radiative cooling film according to claim 1, characterized in that: The porosity of the anti-reflection layer is 39% to 66%; the pore size of the anti-reflection layer is 50 nanometers to 120 nanometers.

6. The radiative cooling film according to claim 1, characterized in that: The thickness of the anti-reflection layer is 200 nanometers to 400 nanometers; and / or the thickness of the emission layer is 80 micrometers to 120 micrometers.

7. A method for preparing a radiation cooling film, characterized in that: The preparation method comprises: forming an emission layer; An anti-reflection layer with a porous structure is formed on one side of the emission layer; wherein, in the visible light wavelength range, the effective refractive indexes of air, the anti-reflection layer and the emission layer gradually increase, and the emission layer and the anti-reflection layer are both made of light-transmitting materials.

8. The method for preparing the radiative cooling film according to claim 7, characterized in that: The forming of the emission layer comprises: The emission layer is formed with a first inorganic material and a second inorganic material as raw materials; the first inorganic material and the second inorganic material are different, and the first inorganic material and the second inorganic material are any two of silicon carbide, titanium dioxide and silicon nitride.

9. The method for preparing the radiative cooling film according to claim 8, characterized in that: The step of forming the emission layer using the first inorganic material and the second inorganic material as raw materials comprises: The emission layer is formed by sputtering using the first inorganic material and the second inorganic material as raw materials in a physical vapor deposition manner.

10. The method for preparing a radiative cooling film according to claim 7, characterized in that: The preparation method comprises: Obtaining a substrate; the substrate is a metal substrate, a plastic substrate, a building material substrate, a textile material substrate or a glass substrate; The forming of the emission layer comprises: The emission layer is formed on one side of the substrate.

11. The method for preparing a radiative cooling film according to claim 7, characterized in that: The anti-reflection layer having a porous structure formed on one side of the emission layer comprises: A prefabricated layer is formed on one side of the emission layer using a third inorganic material and a fourth inorganic material as raw materials; the third inorganic material and the fourth inorganic material are different; The fourth inorganic material in the prefabricated layer is removed so that the third inorganic material forms the anti-reflection layer with a porous structure.

12. The method for preparing a radiative cooling film according to claim 11, characterized in that: The third inorganic material is any one of silicon dioxide and calcium fluoride; the fourth inorganic material is magnesium oxide; The method of using the third inorganic material and the fourth inorganic material as raw materials to form a prefabricated layer on one side of the emission layer comprises: The prefabricated layer is formed by sputtering the third inorganic material and the fourth inorganic material as raw materials on one side of the emission layer by physical vapor deposition; And / or, removing the fourth inorganic material in the prefabricated layer so that the third inorganic material forms the anti-reflection layer with a porous structure comprises: The fourth inorganic material in the prefabricated layer is removed by chemical etching, so that the third inorganic material forms the anti-reflection layer of the porous structure.

13. A radiation cooling product, characterized in that: The radiation cooling product comprises a substrate and the radiation cooling film according to any one of claims 1 to 6, wherein the radiation cooling film is disposed on the substrate, and an emission layer of the radiation cooling film is in contact with the substrate.

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