Radiation refrigeration film and preparation method and application thereof

Abstract

The invention relates to a radiation refrigeration film and a preparation method and application thereof.The preparation method comprises the following steps that a plurality of mask plates are sequentially arranged on a transparent substrate in a stacked mode, each mask plate is provided with a plurality of open holes distributed in an array mode, and the open holes of any two mask plates are equal in number and correspond to each other in position; when vapor deposition starts, the multiple mask plates are placed in an overlapped mode, and along with vapor deposition, at least one mask plate gradually deviates from the initial position, so that the deposition area formed by the radiation refrigeration material through the open pores is gradually reduced; and after vapor deposition is finished, the radiation refrigeration film is obtained. According to the preparation method disclosed by the invention, the light transmittance of the prepared radiation refrigeration film can be improved while relatively high radiation efficiency is maintained, and the radiation refrigeration film can be suitable for scenes such as high-light-transmittance optical windows and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of radiation refrigeration, in particular to a radiation refrigeration film and a preparation method and application thereof. BACKGROUND

[0002] Radiation refrigeration is a green, energy-saving and efficient cooling technology. Under the premise of not consuming energy, the energy of objects on the earth is transmitted to outer space in the form of radiation through the atmospheric window (8-13 pm), thereby realizing spontaneous cooling of the surface of the object. However, the radiation refrigeration film prepared by the traditional method is mainly applied to the fields of textiles and buildings, and has a low light transmittance in the visible light band, which limits its application in some high-transmittance scenarios such as optical windows. SUMMARY

[0003] Therefore, it is necessary to provide a radiation refrigeration film and a preparation method and application thereof to solve the above problems. The preparation method can make the prepared radiation refrigeration film have a high radiation efficiency and a high light transmittance, and can be applied to high-transmittance scenarios such as optical windows.

[0004] A preparation method of a radiation refrigeration film, comprising the following steps:

[0005] A plurality of mask plates are sequentially stacked on the transparent substrate, and the mask plates have a plurality of array-distributed openings, wherein the number of openings of any two mask plates is equal and the positions of the openings correspond to each other.

[0006] At the beginning of vapor deposition, the plurality of mask plates are placed in overlap, and as the vapor deposition proceeds, at least one mask plate gradually deviates from the initial position, so that the deposition area formed by the openings gradually decreases.

[0007] After the vapor deposition is completed, the radiation refrigeration film is obtained.

[0008] In one of the embodiments, the opening shape and the opening size of any two mask plates are the same.

[0009] In one of the embodiments, when there are two mask plates gradually deviating from the initial position, the moving directions of the two mask plates are opposite.

[0010] In one of the embodiments, in any opposite direction movement, the relative movement distance of the two mask plates is 10 nm to 100 nm.

[0011] In one of the embodiments, when the opening shape is an n-sided polygon, there are at least two mask plates gradually deviating from the initial position, and the included angle between the moving directions of the two mask plates is 360° / n, wherein n is an integer greater than or equal to 3.

[0012] In one of the embodiments, there are n mask plates gradually deviating from the initial position.

[0013] In one of the embodiments, the number of times of mask plate deviation is 1-25.

[0014] A radiation cooling film prepared by the preparation method of the radiation cooling film as described above, comprising a transparent substrate, and a radiation cooling layer arranged on the surface of the transparent substrate, wherein the radiation cooling layer comprises arrayed radiation cooling micro-nano structures, and the cross-sectional area of the radiation cooling micro-nano structures parallel to the surface of the transparent substrate decreases in the direction away from the transparent substrate.

[0015] In one of the embodiments, the maximum width of the radiation cooling micro-nano structure is 100-500 nm, the maximum height is 100-500 nm, and the interval distance between two adjacent radiation cooling micro-nano structures is 300-1000 nm.

[0016] The application of the radiation cooling film as described above in an optical window.

[0017] The preparation method of the present application is based on the traditional mask process, and by dynamically adjusting the position of the mask plate during the vapor deposition process, the deposition area formed by the opening gradually decreases in the direction away from the transparent substrate, so as to realize the superposition of the radiation cooling single-layer film structure with gradually changing surface area to form the radiation cooling micro-nano structure. The present application breaks through the subtractive manufacturing method used in the traditional radiation cooling film process and develops an additive manufacturing method, which does not require complex and expensive devices and can realize efficient preparation by using only the mask plate. The method is simple and easy to operate, which is conducive to reducing the manufacturing cost and promoting the application. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiment or prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments described in the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0019] Figure 1 The preparation process schematic diagram of two mask plates gradually deviating from the initial position in an embodiment of the present application;

[0020] Figure 2 The structure schematic diagram of the radiation cooling film in an embodiment of the present application;

[0021] Figure 3 The preparation process schematic diagram of four mask plates gradually deviating from the initial position in another embodiment of the present application.

[0022] Wherein, 10, mask plate; 20, opening; S, deposition area; 101, first mask plate; 102, second mask plate; 103, third mask plate; 104, fourth mask plate; 201, first opening; 202, second opening; 203, third opening; 204, fourth opening; 30, radiative cooling film; 301, transparent substrate; 302, radiative cooling layer; 3021, radiative cooling micro-nano structure. DETAILED DESCRIPTION

[0023] For the purpose of promoting an understanding of the principles of the application, the application will be described in greater detail below. It will, however, be understood that the application can be practiced in many different forms and is not limited to the embodiments or examples described herein. Rather, these embodiments or examples are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the application to those skilled in the art.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the application herein is for the purpose of describing particular embodiments or examples only and is not intended to be limiting of the application. In this application, numbers expressing quantities of ingredients, reaction conditions, and other numerical data, as used in the detailed description are to be understood as being modified in all instances by the term "about". Unless otherwise indicated, all ranges or ratios are approximate, and thus include the minimum and maximum values, and every value between the minimum and maximum values. Further, unless otherwise indicated, the singular forms "a", "an", and "the" include plural referents. In other words, unless otherwise expressly indicated, the use of "a" or "an" or "the" preceding an element or item herein is not intended to substitute for the use of "at least one" or "one or more". Additionally, the words "comprising," "including," containing," and "having" are to be construed in their broadest sense as open-ended terms meaning that other steps, elements, features, or components can be added. Additionally, the words "preferred" and "preferably" are used herein to mean that the described embodiment is more highly preferred or particularly suitable for the described use. Additionally, the words "exemplary" and "example" are used herein to mean serving as an example, instance, or illustration. Any implementation described herein as "exemplary" or as an "example" is not necessarily to be construed as preferred or advantageous over other implementations. Likewise, the term "embodiment of the application" does not require all embodiments to include the discussed feature, advantage or mode of operation. Rather, the term "embodiment of the application" is intended to encompass one or more implementations or examples of the present application.

[0025] CONJUGATE Figure 1 AND Figure 2 As shown in the figure, a preparation method of a radiative cooling film provided by the application includes the following steps:

[0026] Step one, sequentially stack a plurality of mask plates 10 on the transparent substrate 301, the mask plate 10 has a plurality of openings 20 arranged in an array, wherein the number of openings 20 of any two mask plates 10 is equal and the positions correspond to each other;

[0027] Step two, at the beginning of vapor deposition, the plurality of mask plates 10 are overlapped and placed, as the vapor deposition proceeds, at least one mask plate 10 gradually deviates from the initial position, so that the deposition area S formed by the radiative cooling material through the openings gradually decreases;

[0028] Step three, after the vapor deposition is completed, the radiative cooling film 30 is obtained.

[0029] In step one, unlike the traditional mask process which usually uses only one mask plate 10 at a time, the present application simultaneously uses multiple mask plates 10. It can be understood that multiple mask plates 10 means that the mask plates 10 are at least two, and the number of mask plates 10 can correspond to the number of deposited layers of the radiative cooling material.

[0030] It should be noted that the array distribution means that the openings 20 are arranged in order in any direction, and the distance between any two adjacent openings 20 is the same. The present application does not limit the shape of the openings 20, including but not limited to circular, square, and irregular shapes. The shape of the openings 20 of each mask plate 10 can be the same or different; all openings on any mask plate 10 can be of the same shape or of multiple different shapes, and the present application does not limit this. The positions of the openings 20 correspond to each other means that the center points of the openings 20 overlap. It can be understood that when the shapes of the openings 20 in the stacked mask plates 10 are different, such as circular and square, the center points of the circular and square openings can be overlapped. The number of openings 20 of any two mask plates 10 is equal and the positions correspond to each other, in other words, the number of openings 20 of the overall mask plate formed by stacking multiple mask plates 10 is equal to that of any mask plate 10, and there is no problem of reducing the number of openings 20 of the overall mask plate due to any opening 20 being blocked.

[0031] As a preferred embodiment, the shape and size of the openings 20 of any two mask plates 10 are the same.

[0032] In step two, by dynamically adjusting the position of the mask plate 10 during the vapor deposition process, the deposition area S formed by the openings in the direction away from the transparent substrate 301 gradually decreases, thereby realizing the superposition of the radiative cooling single-layer film structure with gradually changing surface area to form the radiative cooling micro-nano structure 3021.

[0033] In the traditional radiative cooling film process, in order to realize the preparation of micro-nano structures, subtractive manufacturing methods such as laser etching are usually used, but this method is complex to operate and the device is expensive, resulting in high manufacturing cost of the radiative cooling film 30. The present application breaks through the traditional mask process and develops an additive manufacturing method, which does not require complex and expensive devices and can realize efficient preparation by using only the mask plate 10. The method is simple and easy to operate, which is conducive to reducing the manufacturing cost and promoting the application.

[0034] It should be noted that the overlapping placement of multiple mask plates 10 means that the multiple mask plates 10 are stacked one by one, and the circumferential length is consistent. It can be understood that when the shapes and sizes of the openings 20 of all mask plates 10 are the same, the overall mask plate formed by overlapping multiple mask plates 10 is only different from any mask plate 10 in that the thickness is the superposition of multiple mask plates 10.

[0035] In an embodiment of the present application, when there is a case that one mask plate 10 gradually deviates from the initial position as the vapor deposition proceeds, it can be understood that due to the displacement of one mask plate 10 relative to the transparent substrate 301 or the remaining mask plates, the edges of the openings in the displaced mask plate 10 are partially blocked, resulting in a smaller projected area of the openings formed by the overlapped placement of the plurality of mask plates 10 after displacement, thereby reducing the deposition area S formed by the radiation refrigeration material passing through the openings.

[0036] In another embodiment of the present application, when there is a case that at least two mask plates 10 gradually deviate from the initial position as the vapor deposition proceeds, it can be understood that when the directions in which the plurality of mask plates 10 deviate from the initial position are the same, the plurality of mask plates 10 can be regarded as a whole mask plate, and in this case, it is equivalent to a displacement of the whole mask plate relative to the transparent substrate 301 or the remaining mask plates, and the edges of the openings in the displaced whole mask plate are partially blocked, resulting in a smaller projected area of the openings formed by the overlapped placement of the plurality of mask plates 10 after displacement, thereby reducing the deposition area S formed by the radiation refrigeration material passing through the openings; when the directions in which the plurality of mask plates 10 deviate from the initial position are different, the plurality of mask plates 10 are relatively displaced relative to the transparent substrate 301 or the remaining mask plates, and the edges of the openings in the displaced plurality of mask plates 10 are partially blocked, resulting in a smaller projected area of the openings formed by the overlapped placement of the plurality of mask plates 10 after displacement, thereby reducing the deposition area S formed by the radiation refrigeration material passing through the openings.

[0037] It should be noted that the deposition method described in the present application is intermittent deposition or continuous deposition, and the movement of the mask plate 10 can be controlled outside the deposition device. The movement of the mask plate 10 can be intermittent or continuous, and it can be understood that when the mask plate 10 moves intermittently, there is a stepped structure between adjacent two radiation refrigeration material deposition films, and the width of the step is less than or equal to the displacement distance; when the deposition method is continuous deposition, the movement time of the mask plate 10 is relatively short and can be ignored relative to the magnetron time, so it does not affect the formation of the stepped structure.

[0038] It should be noted that the present application does not limit the movement direction of the mask plate 10, and the mask plate 10 can move in any direction around the center point of the mask plate 10 in a plane parallel to the transparent substrate 301. When there are two or more mask plates 10 gradually deviating from the initial position, it is preferred that the movement directions of the two or more mask plates 10 are different, and it is more preferred that the movement directions of all the mask plates 10 are evenly distributed by 360°, which is beneficial to the uniform change of the projected area of the openings, reduces the deposition area formed by the radiation refrigeration material passing through the openings, and thus makes the radiation refrigeration micro-nano structure 3021 regular and ordered, and further balances the high radiation efficiency and high light transmittance of the radiation refrigeration film 30.

[0039] In an embodiment of the present application, when there are two mask plates 10 gradually deviating from the initial position, the moving directions of the two mask plates 10 are opposite. In combination Figure 1 As shown in FIG. 1, the two mask plates 10 are respectively denoted as a first mask plate 101 and a second mask plate 102, wherein the second mask plate 102 is located between the first mask plate 101 and the transparent substrate 301. At the beginning of the vapor deposition, since the first mask plate 101 and the second mask plate 102 can completely overlap, the deposition area S formed at this time is equal to the opening area. As the vapor deposition proceeds, the first mask plate 101 and the second mask plate 102 move in opposite directions. At this time, part of the edge of the opening 202 in the second mask plate 102 blocks part of the structure of the opening 201 in the first mask plate 101, so that the projection area of the opening formed by the overlapped placement of the first mask plate 101 and the second mask plate 102 after displacement becomes smaller, thereby reducing the deposition area S formed by the opening through which the radiation refrigeration material passes.

[0040] As preferred, in any opposite direction movement, the relative movement distance of the two mask plates 10 is 10 nm to 100 nm, including but not limited to any point value or range value between any two of 10 nm, 20 nm, 40 nm, 60 nm, 80 nm, 100 nm, and more preferably 10 nm to 50 nm. It should be noted that the relative movement distance generated by each displacement can be the same or different, and the present application does not limit this.

[0041] It can be understood that, when the two mask plates 10 move in opposite directions, they can move in the direction perpendicular to the opposite sides of the mask plate 10 as shown in FIG. 1, or they can move in the diagonal direction of the mask plate 10, and the present application does not limit this. Figure 1

[0042] In another embodiment of the present application, when the opening shape is an n-sided polygon, there are at least two mask plates gradually deviating from the initial position, and the included angle between the moving directions of the two mask plates is 360° / n, wherein n is an integer greater than or equal to 3. For example, when the opening shape is a triangle, there can be two mask plates gradually deviating from the initial position, and preferably the moving directions of the two mask plates are on the perpendicular lines of the adjacent sides of the triangle, and the included angle between the perpendicular lines of the adjacent sides of the triangle is 120°, i.e. the included angle between the moving directions of the two mask plates is 360° / 3 = 120°. When the opening shape is a quadrilateral, there can be two mask plates gradually deviating from the initial position, and preferably the moving directions of the two mask plates are on the perpendicular lines of the adjacent sides of the quadrilateral, and the included angle between the perpendicular lines of the adjacent sides of the quadrilateral is 90°, i.e. the included angle between the moving directions of the two mask plates is 360° / 4 = 90°.

[0043] ​As preferred, when the opening shape is an n-gon, there are n mask plates gradually deviating from the initial position, and the included angle of the motion directions of two mask plates is 360° / n, for example, when the opening shape is a triangle, there can be three mask plates gradually deviating from the initial position, and the motion directions of each mask plate are on the perpendicular lines of the triangle sides, the included angle of the perpendicular lines of adjacent sides in the triangle is 120°, and the included angle of the motion directions of two mask plates is 360° / 3 = 120°; when the opening shape is a square, there can be four mask plates gradually deviating from the initial position, and the motion directions of each mask plate are on the perpendicular lines of the square sides or on the diagonal lines of the square, the included angle of the perpendicular lines of adjacent sides in the square is 90° or the included angle of the two diagonal lines of the square is 90°, and the included angle of the motion directions of two mask plates is 360° / 4 = 90°. Specifically, referring to FIG. 1, the four mask plates 10 are respectively marked as a first mask plate 101, a second mask plate 102, a third mask plate 103, and a fourth mask plate 104, wherein the second mask plate 102, the third mask plate 103, and the fourth mask plate 104 are sequentially located between the first mask plate 101 and the transparent substrate 301. At the beginning of the vapor deposition, the first mask plate 101 can completely overlap the second mask plate 102, the third mask plate 103, and the fourth mask plate 104, and at this time, the deposition area S formed is equal to the opening area. As the vapor deposition proceeds, the first mask plate 101, the second mask plate 102, the third mask plate 103, and the fourth mask plate 104 respectively move along the perpendicular lines of the square sides, and at this time, due to the displacement, part of the edges of the opening 201 in the first mask plate 101, the opening 202 in the second mask plate 102, the opening 203 in the third mask plate 103, and the opening 204 in the fourth mask plate 104 are shielded from each other, and after the shielding, the projection area of the opening becomes smaller, thereby reducing the deposition area S formed by the radiation refrigeration material passing through the opening. Figure 3

[0044] It should be noted that the included angle of the motion directions of two mask plates represents the included angle of the straight lines on which the motion directions of the two mask plates are located, and the motion direction of the mask plate can be judged by the moving direction of the center point of the mask plate. The included angle of the motion directions of two mask plates in the present application is the included angle of two adjacent motion directions, that is, there is no motion direction of other mask plates in the included angle region.

[0045] In another embodiment of the present application, when there are three mask plates 10 gradually deviating from the initial position, the included angle of the motion directions of any two mask plates 10 of the three mask plates 10 is 120°.

[0046] ​In an embodiment of the present application, the number of times of deviation of the mask plate 10 is 1-25. It can be understood that the more the number of times of deviation of the mask plate 10, the more the number of layers of the deposited film of the radiative cooling material formed. For example, when the number of times of deviation of the mask plate 10 is 8, the number of layers of the deposited film of the radiative cooling material formed is 8.

[0047] In an embodiment of the present application, before vapor deposition is performed, the transparent substrate 301 is first placed in an ethanol solution for ultrasonic treatment, and then the surface is blown to dry with nitrogen or inert gas, and then dried at 60-90℃ for 30-60min to remove impurities attached to the surface of the transparent substrate 301. The transparent substrate 301 described in the present application includes but is not limited to glass.

[0048] It should be noted that before vapor deposition is performed using the mask plate 10, a layer of radiative cooling material can be deposited on the surface of the transparent substrate 301 where the mask plate 10 is placed.

[0049] In an embodiment of the present application, the radiative cooling material includes but is not limited to at least one of silicon dioxide, silicon carbide, titanium dioxide, and silicon nitride.

[0050] In an embodiment of the present application, the vapor deposition process described in the present application is preferably magnetron sputtering, wherein the vacuum degree is 1x10 -5 Pa-1x10 -4 Pa, the argon flow rate is 10-40mL / min, the working gas pressure is 0.5-2Pa, the sputtering power is 50-100w, and the sample stage temperature is 150-300℃. When sputtering starts, the sputtering time is determined according to the required thickness of the deposited film of the radiative cooling material, and the magnetron time interval between adjacent two deviations is 30-60min.

[0051] Further preferably, the magnetron sputtering is performed in a mode of A target and B target double-target co-sputtering, wherein the materials of the A target and the B target are independently selected from two of silicon dioxide, silicon carbide, titanium dioxide, and silicon nitride.

[0052] In combination Figure 2 As shown in FIG. 1, a radiative cooling film 30 prepared by the preparation method of the radiative cooling film described above is provided in the present application, which includes a transparent substrate 301, and a radiative cooling layer 302 arranged on the surface of the transparent substrate 301. The radiative cooling layer 302 includes arrayed radiative cooling micro-nano structures 3021, and the cross-sectional area of the radiative cooling micro-nano structures 3021 parallel to the surface of the transparent substrate 301 decreases in the direction away from the transparent substrate 301.

[0053] It should be noted that, considering that the preparation method is additive manufacturing, the radiation refrigeration micro-nano structure 3021 is actually composed of a plurality of layers of radiation refrigeration material deposition films stacked, and the present application does not limit the number of layers of the radiation refrigeration material deposition film, which is preferably 1-25 layers.

[0054] In an embodiment of the present application, the maximum width of the radiation refrigeration micro-nano structure 3021 is 100-500 nm, the maximum height is 100-500 nm, and the spacing distance between adjacent two radiation refrigeration micro-nano structures is 300-1000 nm. It can be understood that the maximum width represents the contact surface width of the radiation refrigeration micro-nano structure 3021 and the transparent substrate 301, i.e. the bottom surface width of the radiation refrigeration micro-nano structure 3021; the maximum height represents the vertical distance from the bottom surface to the top surface of the radiation refrigeration micro-nano structure 3021. By adjusting the size and spacing distance of the radiation refrigeration micro-nano structure 3021, the distribution density of the radiation refrigeration micro-nano structure 3021 can be controlled, which is beneficial to further balance the high radiation efficiency and high light transmittance of the radiation refrigeration film 30.

[0055] The present application also provides an application of the radiation refrigeration film as described above in an optical window.

[0056] The radiation refrigeration film provided by the present application not only has high radiation efficiency, but also has high light transmittance in the visible light band, overcoming the defects such as insufficient light transmittance of traditional radiation refrigeration films, and can be applied to optical windows and other scenes with high light transmittance.

[0057] Hereinafter, the radiation refrigeration film, the preparation method and the application thereof will be further described through the following specific examples. However, those skilled in the art will understand that the following examples are only used to illustrate the present application, and should not be regarded as limiting the scope of the present application. If the specific conditions are not specified in the examples, the conventional conditions or the conditions recommended by the manufacturer are used. If the reagents or instruments used are not specified by the manufacturer, they are all conventional products that can be obtained by purchase.

[0058] Example 1

[0059] The transparent glass was placed in an ethanol solution and ultrasonicated for 40 min, then the surface was blown to dryness with nitrogen, and then placed in an oven at 80°C for drying for 30 min.

[0060] Two mask plates with the same size as the transparent glass were used, both of which had square openings with the same number, size and position. Specifically, the side length of the square opening was 300 μm, the height was 280 nm, and the opening interval was 1000 nm. The treated transparent glass was placed in a magnetron vacuum cavity, and the positions of the two mask plates were adjusted so that the two mask plates overlapped. A target and a target were used for co-sputtering, and the target and the target were made of silicon dioxide and silicon carbide, respectively. The vacuum degree was adjusted to about 1x10-5 Pa, argon flow rate is about 20 mL / min, working pressure is about 1 Pa, sputtering power is about 60 w, sample stage temperature is about 210℃; start sputtering, first keep the mask plate stationary, the magnetron time is 15 min; then move the two mask plates horizontally in opposite directions along the left and right sides, the relative motion distance of the two mask plates is 20 nm, the movement is controlled within 1 second, which can be ignored relative to the magnetron time, continue magnetron sputtering for 30 min, repeat the above movement 14 times, each time the same distance, the deposition area variable is also the same, each time interval 15 min magnetron sputtering, finally the radiation refrigeration film is prepared.

[0061] Example 2

[0062] The transparent glass is placed in the ethanol solution and ultrasonically treated for 45 min, then the surface is blown to surface dry with nitrogen, and then placed in an oven at 60℃ for drying for 50 min.

[0063] Four mask plates with the same size as the transparent glass are used, and the four mask plates all have square openings with the same number, size and position. Specifically, the side length of the square opening is 400 μm, the height is 200 nm, and the opening interval is 500 nm. The treated transparent glass is placed in the magnetron vacuum cavity, and the positions of the two mask plates are adjusted to make the four mask plates coincide. A target and a B target are used for co-sputtering, the A target and the B target use titanium dioxide and silicon nitride respectively, the vacuum degree is extracted to about 5x10 -4 Pa, argon flow rate is about 30 mL / min, working pressure is about 2 Pa, sputtering power is about 100 w, sample stage temperature is about 250℃; start sputtering, first keep the mask plate stationary, the magnetron time is 20 min; then move the four mask plates horizontally in four directions, and the included angle between any two adjacent motion directions is 90°, wherein the relative motion distance of the mask plates in any two opposite motion directions is 80 nm, the movement is controlled within 1 second, which can be ignored relative to the magnetron time, and the magnetron sputtering is continued for 50 min; repeat the above movement 4 times, control the same distance each time, and interval 50 min magnetron sputtering, finally the radiation refrigeration film is prepared.

[0064] Example 3

[0065] The transparent glass is placed in the ethanol solution and ultrasonically treated for 45 min, then the surface is blown to surface dry with nitrogen, and then placed in an oven at 60℃ for drying for 50 min.

[0066] Three mask plates with the same size as the transparent glass are used, and the three mask plates all have triangular openings with the same number, size and position. Specifically, the triangular openings have a side length of 500 μm and a height of 300 nm, and the openings are spaced 750 nm apart. The treated transparent glass is placed in a magnetron vacuum cavity, and the positions of the two mask plates are adjusted so that the three mask plates overlap. A target A and a target B are used for co-sputtering, and the target A and the target B are titanium dioxide and silicon nitride, respectively. The vacuum degree is adjusted to about 1x10 -4 Pa, the argon flow rate is about 15 mL / min, the working gas pressure is about 1.5 Pa, the sputtering power is about 80 w, and the sample table temperature is about 230℃. The sputtering is started, and the mask plates are first kept stationary for 35 min. Then, the three mask plates are moved horizontally in three directions, the included angle between any two directions is 120°, and the moving distance is 50 nm. The movement is controlled to be completed within 1 second, which can be ignored relative to the magnetron time, and the magnetron sputtering is continued for 35 min. The above movement is repeated 5 times, the same distance is controlled for each movement, and the magnetron sputtering is continued for 35 min each time. Finally, the radiation refrigeration film is obtained.

[0067] The radiation refrigeration films obtained in all the examples are subjected to performance testing, and the test results are shown in Table 1.

[0068] Table 1

[0069]

[0070] According to Table 1, the prepared radiation refrigeration film has high radiation efficiency and high light transmittance.

[0071] The technical features of the above-described examples can be combined in any manner. To make the description concise, all possible combinations of the technical features in the above-described examples are not described, but as long as the combinations of the technical features do not contradict each other, they should be considered within the scope of the present disclosure.

[0072] The above-described examples only express several embodiments of the present disclosure, and the description is more specific and detailed, but it should not be construed as limiting the scope of the patent. It should be noted that for ordinary skilled persons in the art, without departing from the concept of the present disclosure, a number of modifications and improvements can be made, which are within the scope of the present disclosure. Therefore, the scope of protection of the present patent should be subject to the appended claims.

Claims

1. A method of making a radiative cooling film, the method comprising: The method comprises the following steps: a plurality of mask plates are sequentially stacked on a transparent substrate, the mask plates have a plurality of array-distributed openings, wherein the number of openings of any two mask plates is equal and the positions of the openings correspond to each other; at the beginning of vapor deposition, the plurality of mask plates are placed in overlap, as the vapor deposition proceeds, at least one mask plate gradually deviates from the initial position, so that the deposition area formed by the openings gradually decreases in the direction away from the transparent substrate; after the vapor deposition is completed, a radiation refrigeration film is obtained.

2. The method of claim 1, wherein the radiation-reflecting film is prepared by a method comprising: The opening shape and opening size of any two mask plates are the same.

3. The method of claim 1 or 2, wherein the radiation-cooled membrane is prepared by a method comprising: When there are two mask plates gradually deviating from the initial position, the moving directions of the two mask plates are opposite.

4. The method of claim 3, wherein the radiation-reflecting film is prepared by a method comprising: In any one opposite direction movement, the relative movement distance of the two mask plates is 10 nm to 100 nm.

5. The method of claim 1 or 2, wherein the radiation-cooled membrane is prepared by a method comprising: When the opening shape is an n-sided polygon, at least two mask plates gradually deviate from the initial position, and the included angle between the moving directions of the two mask plates is 360° / n, wherein n is an integer greater than or equal to 3.

6. The method of claim 5, wherein the radiation-reflecting film is prepared by a process comprising: There are n mask plates gradually deviating from the initial position.

7. The method of claim 1, wherein the radiation-reflecting film is prepared by a method comprising: forming a first layer on a substrate; forming a second layer on the first layer; and forming a third layer on the second layer. The number of times of deviation of the mask plate is 1 to 25.

8. The radiative cooling film prepared by the method of any one of claims 1-7. The radiation refrigeration film comprises a transparent substrate and a radiation refrigeration layer arranged on the surface of the transparent substrate, the radiation refrigeration layer comprises array-distributed radiation refrigeration micro-nano structures, and the cross-sectional area of the radiation refrigeration micro-nano structures parallel to the surface of the transparent substrate decreases in the direction away from the transparent substrate.

9. The radiative cooling film of claim 8, wherein, The maximum width of the radiation refrigeration micro-nano structure is 100 nm to 500 nm, the maximum height is 100 nm to 500 nm, and the spacing distance between adjacent two radiation refrigeration micro-nano structures is 300 nm to 1000 nm.

10. Application of the radiation refrigeration film according to claim 8 or 9 in an optical window.

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