Spectral selective absorption film layer, structure, device, application and film layer preparation method

Abstract

The invention relates to the technical field of wave-absorbing materials, and discloses a spectrum selective absorption film layer, a structure, a device, application and a film layer preparation method, the spectrum selective absorption film layer comprises a substrate, the surface of the substrate is provided with a functional area, and the functional area is provided with a micro-nano structure; and the spectrum selective absorption layer is arranged on the surface of the substrate and located in the functional area, and the spectrum selective absorption layer comprises at least one of aluminum hydroxide powder and boehmite powder. The spectrum selective absorption film layer is simple in preparation method, stable in structure and excellent in spectrum selective absorption performance.

Description

Technical Field

[0001] The present application relates to the technical field of absorbing materials, and in particular to spectrally selective absorbing films, structures, devices, applications, and methods for preparing the films. Background Art

[0002] At present, films with spectrally selective absorption properties have important applications in many fields such as passive cooling, radiation cooling, radiation heating, refractory materials, infrared camouflage, and infrared detection. For example, radiation cooling applications usually require that the surface of the material has a high reflectivity in the ultraviolet to near-infrared band to reduce the absorption of solar energy, and at the same time has a high emissivity in the mid-infrared band to enhance thermal radiation heat dissipation, thereby achieving the effect of cooling the surface of the material. However, the spectrally selective absorption film layer in the related art has problems such as complex preparation methods, poor adhesion, and poor environmental adaptability, which limits its large-scale application. Therefore, developing a spectrally selective absorption film layer with a simple preparation method, stable structure and excellent spectrally selective absorption properties is one of the current challenges.

[0003] Application Contents

[0004] The present application aims to address, at least to some extent, one of the technical problems in the related art. To this end, one object of the present application is to provide a spectrally selective absorption film layer, structure, device, application, and film layer preparation method and application. The preparation method of the spectrally selective absorption film layer of the present application is simple, and the prepared spectrally selective absorption film layer has excellent spectrally selective absorption performance.

[0005] In a first aspect of the present application, a spectrally selective absorption film layer is proposed, comprising:

[0006] A substrate, wherein the surface of the substrate has a functional area, and the functional area has a micro-nano structure;

[0007] A spectrally selective absorption layer is provided on the surface of the substrate and is located in the functional area. The spectrally selective absorption layer includes at least one of aluminum hydroxide powder and boehmite powder.

[0008] The spectrally selective absorption film layer is obtained by setting a spectrally selective absorption layer on the surface of a substrate with a micro-nano structure. The micro-nano structure of the substrate surface can enable the spectrally selective absorption layer to be stably set on the substrate surface to avoid falling off. At the same time, the selected aluminum hydroxide powder and boehmite powder are both high infrared emissive materials with excellent spectral regulation capabilities. The combination of the two helps to obtain a spectrally selective absorption film layer with a stable structure and excellent spectrally selective absorption performance.

[0009] In some embodiments of the present application, the spectrally selective absorption layer is composed of at least one of aluminum hydroxide powder and boehmite powder, thereby facilitating the formation of a spectrally selective absorption film layer with spectral control capability.

[0010] In some embodiments of the present application, the spectrally selective absorption layer satisfies at least one of the following conditions:

[0011] The particle size of the aluminum hydroxide powder is 0.01 μm to 100 μm;

[0012] The particle size of the boehmite powder is 0.01 μm to 100 μm, which helps to further obtain a spectrally selective absorption film layer with a stable structure.

[0013] In some embodiments of the present application, the thickness of the spectrally selective absorption layer is 1 μm to 1000 μm, thereby helping to improve the spectrum control capability of the spectrally selective absorption film layer.

[0014] In some embodiments of the present application, the substrate comprises at least one of a metal material, a ceramic material, a semiconductor material, and a polymer material, thereby providing a wide range of substrate materials and a large selection.

[0015] In some embodiments of the present application, the substrate material satisfies at least one of the following conditions:

[0016] The metal material includes at least one of gold, silver, platinum, aluminum, aluminum alloy, magnesium, magnesium alloy, zinc, zinc alloy, copper, copper alloy, titanium, titanium alloy, tungsten, tungsten alloy, nickel, nickel alloy, manganese, manganese alloy, iron, and steel;

[0017] The ceramic material includes at least one of aluminum oxide, zirconium oxide, silicon oxide, silicon nitride, silicon carbide, boron nitride, boron carbide, aluminum nitride, titanium nitride, barium titanate, lithium niobate, lithium tantalate, titanium oxide, magnesium oxide, zinc oxide, vanadium oxide, tin oxide, hydroxyapatite, silicate glass, and oxynitride ceramics;

[0018] The semiconductor material includes at least one of silicon, germanium, gallium arsenide, gallium oxide, gallium nitride, cadmium telluride, zinc oxide, zinc selenide, silicon carbide, indium phosphide, and diamond;

[0019] The polymer material includes at least one of polydimethylsiloxane, polyethylene terephthalate, polycarbonate, polymethyl methacrylate, polyimide, polytetrafluoroethylene, polystyrene, polyethylene, polypropylene, polyamide, polyurethane, and photoresist. Thus, the substrate material selection is wide, which helps to further improve the selectivity of the substrate material.

[0020] In some embodiments of the present application, the micro-nanostructure includes a microstructure and / or a nanostructure, wherein the nanostructure is located on the surface of the substrate or the microstructure; wherein the microstructure includes at least one of a micro-protrusion structure and a micro-recess structure; and the nanostructure includes at least one of nanoparticles, nanoripples, nanosynapses, nanopits, nanoprotrusions, nanogratings, nanohairs, nanowires, nanotubes, nanosheets, nanoflowers, and nanograss. This facilitates the selection of different processing methods based on the characteristics of the material to achieve the micro-nanostructure, while also enhancing the bonding of the spectrally selective absorption layer to the substrate.

[0021] In some embodiments of the present application, the lateral dimension of the microstructure is 1 μm to 1000 μm, the height of the microstructure is 1 μm to 1000 μm, and the spacing between two adjacent microstructures is 1 μm to 1000 μm. The lateral dimension of the microstructure is the maximum distance between any two points on the contour line of the microstructure close to the surface of the substrate; the height of the microstructure is the maximum distance between the microstructure and the substrate surface in a direction perpendicular to the substrate surface; and the spacing between two adjacent microstructures is the shortest distance between the surfaces of two adjacent microstructures close to the substrate. This helps further enhance the bonding of the spectrally selective absorption layer to the substrate.

[0022] In a second aspect of the present application, a spectrally selective absorption structure is proposed, comprising:

[0023] ontology;

[0024] The aforementioned spectrally selective absorption film layer is disposed on at least a portion of the surface of the body, thereby helping to obtain a spectrally selective absorption structure that is simple to process and has spectrally selective absorption performance.

[0025] In some embodiments of the present application, at least a portion of the body constitutes a substrate in the film layer, thereby reducing costs during use and making the spectrally selective absorption structure suitable for large-scale application.

[0026] The third aspect of the present application provides a method for preparing a spectrally selective absorption film layer, comprising:

[0027] Processing at least a portion of the surface of the substrate to form a functional area having a micro-nano structure;

[0028] The spectrally selective absorption material is coated on at least a portion of the functional area, and then scraped and compacted in sequence to form the spectrally selective absorption film layer. Thus, the preparation method is simple, and the spectrally selective absorption film layer prepared by this method has excellent spectral control capabilities.

[0029] In some embodiments of the present application, processing at least a portion of the surface of the substrate includes at least one of laser processing, mechanical processing, ultrasonic processing, electrical discharge machining, dry etching, wet etching, imprinting, template processing, 3D printing, and photolithography. Preferably, the processing is laser processing. This facilitates adapting different processing methods to different substrate materials.

[0030] In some embodiments of the present application, the laser processing satisfies at least one of the following conditions:

[0031] The wavelength of the laser processing is 10nm to 20000nm;

[0032] The power of the laser processing is 1mW to 10kW;

[0033] The pulse width of the laser processing is 1 fs to 1 s, which helps to further process the substrate surface to obtain micro-nano structures.

[0034] In some embodiments of the present application, the spectrally selective absorption raw material is provided in the form of dry powder and / or slurry, which is simple to operate and can be used to prepare a spectrally selective absorption film layer according to actual conditions.

[0035] In a fourth aspect of the present application, a spectrally selective absorption device is provided, comprising the aforementioned spectrally selective absorption film layer or spectrally selective absorption structure, thereby having excellent spectrally selective absorption performance.

[0036] The fifth aspect of the present application proposes the application of the aforementioned spectrally selective absorption film layer or spectrally selective absorption structure or spectrally selective absorption device in the fields of passive cooling, radiation cooling, radiation heating, refractory materials, infrared camouflage, infrared detection, etc.

[0037] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a scanning electron microscope image of a substrate obtained by laser processing in one embodiment of the present application.

[0039] Figure 2 This is a scanning electron microscope image of a substrate obtained by laser processing in one embodiment of the present application.

[0040] Figure 3 This is a scanning electron microscope image of a substrate obtained by laser processing in one embodiment of the present application.

[0041] Figure 4This is a scanning electron microscope image of a substrate obtained by laser processing in one embodiment of the present application.

[0042] Figure 5 This is a reflectivity test result diagram of the spectrally selective absorption film layer in one embodiment of the present application obtained by using an ultraviolet-visible-near-infrared spectrophotometer.

[0043] Figure 6 This is a reflectivity test result diagram of the spectrally selective absorption film layer in one embodiment of the present application obtained by using an ultraviolet-visible-near-infrared spectrophotometer.

[0044] Figure 7 This is a reflectivity test result diagram of the spectrally selective absorption film layer in one embodiment of the present application obtained by using a Fourier transform infrared spectrometer.

[0045] Figure 8 This is a reflectivity test result diagram of the spectrally selective absorption film layer in one embodiment of the present application obtained by using a Fourier transform infrared spectrometer.

[0046] Figure 9 This is a reflectivity test result diagram of the spectrally selective absorption film layer in one embodiment of the present application obtained by using an ultraviolet-visible-near-infrared spectrophotometer.

[0047] Figure 10 This is a reflectivity test result diagram of the spectrally selective absorption film layer in one embodiment of the present application obtained by using a Fourier transform infrared spectrometer.

[0048] Figure 11 This is a reflectivity test result diagram of the spectrally selective absorption film layer in one embodiment of the present application obtained by using an ultraviolet-visible-near-infrared spectrophotometer.

[0049] Figure 12 This is a reflectivity test result diagram of the spectrally selective absorption film layer in one embodiment of the present application obtained by using a Fourier transform infrared spectrometer.

[0050] Figure 13 This is a reflectivity test result diagram of a spectrally selective absorption layer in a comparative example of the present application obtained by using a Fourier transform infrared spectrometer. DETAILED DESCRIPTION

[0051] The embodiments of the present application are described in detail below. The embodiments described below are exemplary and intended to be used to explain the present application, but should not be understood as limiting the present application.

[0052] This application is based on the following findings and knowledge of the applicant:

[0053] As mentioned above, the preparation method of the spectrally selective absorption surface in the related art is complex and has poor adhesion. Based on this, the inventors considered placing a material with spectral control ability directly on the substrate plane to prepare a film layer with spectrally selective absorption performance. For example, aluminum hydroxide and boehmite are common infrared emitting materials with excellent spectral control ability. However, directly using aluminum hydroxide or boehmite to press into a film layer is unstable and easily broken into powder, resulting in the inability to have stable spectral selectivity. If aluminum hydroxide powder and boehmite powder are coated on the substrate surface, the structural instability problem caused by the use of aluminum hydroxide and boehmite alone can be solved to a certain extent. However, when aluminum hydroxide or boehmite is directly coated on a smooth substrate surface, it is easy to peel off, which will also affect the structural stability of the spectrally selective absorption film layer, thereby affecting the spectrally selective absorption performance. Based on the above considerations, the applicant has developed a new spectrally selective absorption film layer with a stable structure, a simple preparation method, and excellent spectrally selective absorption performance.

[0054] In a first aspect of the present application, a spectrally selective absorption film layer is proposed, comprising:

[0055] A substrate, wherein the surface of the substrate has a functional area, and the functional area has a micro-nano structure;

[0056] A spectrally selective absorption layer is provided on the surface of the substrate and is located in the functional area. The spectrally selective absorption layer includes at least one of aluminum hydroxide powder and boehmite powder.

[0057] The spectrally selective absorption film layer is obtained by setting a spectrally selective absorption layer on the surface of a substrate with a micro-nano structure. The micro-nano structure of the substrate surface can stably set the spectrally selective absorption layer on the substrate surface to avoid falling off, which can improve the mechanical stability of the spectrally selective absorption film layer; at the same time, aluminum hydroxide powder and boehmite powder are both high infrared emissivity materials with excellent spectral regulation capabilities. At the same time, the chemical properties are stable, which can ensure that no chemical reactions occur in complex environments, which helps to improve the environmental adaptability of the spectrally selective absorption film layer. Therefore, the spectrally selective absorption film layer of the present application has a stable structure, strong environmental adaptability and excellent spectrally selective performance.

[0058] Spectral selectivity refers to high reflectivity (>80%) in the ultraviolet to near-infrared band (0.25μm~2.5μm) and high emissivity (>80%) in the mid-infrared band (2.5μm~25μm).

[0059] In some embodiments of the present application, the spectrally selective absorption layer is composed of at least one of aluminum hydroxide powder and boehmite powder. Aluminum hydroxide has high infrared emissivity and can efficiently radiate heat outward in the atmospheric window band (8μm~13μm), with a good radiation cooling effect; the crystal structure of boehmite is flaky or blocky, which is conducive to forming a specific microstructure in the material system, optimizing the scattering, absorption and emission path of light, thereby improving the spectrum control ability. However, aluminum hydroxide powder and boehmite powder themselves are difficult to form a film layer, making it difficult to exert their excellent spectrum control ability. In this application, aluminum hydroxide powder and boehmite powder are combined with a substrate with a micro-nano structure, and aluminum hydroxide powder and boehmite powder are firmly set on the surface of the substrate. This can not only give play to the excellent light control ability of aluminum hydroxide powder and boehmite powder, but also ensure that aluminum hydroxide powder and boehmite powder do not fall off on the surface of the substrate. Thus, it is helpful to further obtain a spectrally selective absorption film layer with spectrum control ability.

[0060] In some embodiments of the present application, the particle size of the aluminum hydroxide powder is 0.01μm to 100μm, specifically, it can be 0.01μm, 0.1μm, 1μm, 2μm, 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, 20μm, 30μm, 40μm, 50μm, 60μm, 70μm, 80μm, 90μm, 100μm, etc. The particle size of the aluminum hydroxide powder within the above range helps to be evenly dispersed on the surface of the substrate, making the spectrally selective absorption film layer more uniform and stable, thereby improving the performance of the film layer.

[0061] In some embodiments of the present application, the particle size of the boehmite powder is 0.01μm to 100μm, specifically, 0.01μm, 0.1μm, 1μm, 2μm, 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, 20μm, 30μm, 40μm, 50μm, 60μm, 70μm, 80μm, 90μm, 100μm, etc. The particle size of the boehmite powder within the above range helps to be evenly dispersed on the surface of the substrate, making the spectrally selective absorption film layer more uniform and stable, thereby improving the performance of the film layer.

[0062] In some embodiments of the present application, the thickness of the spectrally selective absorption layer is 1μm to 1000μm, specifically, it can be 1μm, 10μm, 20μm, 30μm, 40μm, 50μm, 60μm, 70μm, 80μm, 90μm, 100μm, 200μm, 300μm, 400μm, 500μm, 600μm, 700μm, 800μm, 900μm, 1000μm, etc. The thickness of the spectrally selective absorption layer within the above range helps to further improve the structural stability and spectral regulation ability of the spectrally selective absorption film layer, and to a certain extent avoids the problems of weak spectral regulation ability of the spectrally selective absorption film layer due to the thin thickness of the spectrally selective absorption layer, and unstable structure of the spectrally selective absorption film layer and waste of raw materials due to the thick thickness of the spectrally selective absorption layer.

[0063] In some embodiments of the present application, the substrate includes at least one of a metal material, a ceramic material, a semiconductor material, and a polymer material. Specifically, the metal material includes at least one of gold, silver, platinum, aluminum, aluminum alloy, magnesium, magnesium alloy, zinc, zinc alloy, copper, copper alloy, titanium, titanium alloy, tungsten, tungsten alloy, nickel, nickel alloy, manganese, manganese alloy, iron, and steel. The above metal materials have good electrical conductivity and thermal conductivity, which helps to maintain the stability of light regulation performance in different environments. At the same time, the above metal materials are not easy to deform or damage. The above ceramic materials include at least one of aluminum oxide, zirconium oxide, silicon oxide, silicon nitride, silicon carbide, boron nitride, boron carbide, aluminum nitride, titanium nitride, barium titanate, lithium niobate, lithium tantalate, titanium oxide, magnesium oxide, zinc oxide, vanadium oxide, tin oxide, hydroxyapatite, silicate glass, and oxynitride ceramics. The above ceramic materials have stable chemical properties, high hardness, and wear resistance, which helps to improve the structural stability of the spectrally selective absorption film layer. At the same time, they have different refractive indices. It helps to regulate and enhance the spectral regulation capability of the spectrally selective absorption film layer; the semiconductor material includes at least one of silicon, germanium, gallium arsenide, gallium oxide, gallium nitride, cadmium telluride, zinc oxide, zinc selenide, silicon carbide, indium phosphide, and diamond. The above semiconductor materials have characteristics such as adjustable band gap and nonlinear optical response, which help to regulate and enhance the spectral regulation capability of the spectrally selective absorption film layer; the polymer material includes at least one of polydimethylsiloxane, polyethylene terephthalate, polycarbonate, polymethyl methacrylate, polyimide, polytetrafluoroethylene, polystyrene, polyethylene, polypropylene, polyamide, polyurethane, and photoresist. The above polymer material has the advantages of light weight, strong processability, adjustable refractive index, and designable wave transmission / absorbing performance. In particular, in the infrared band, its absorption capability for specific wavelengths can be enhanced through doping, compounding or structural design.

[0064] In some embodiments of the present application, the micro-nano structure of the functional area can be a micron structure, a nanostructure, or a nanostructure on the surface of a micron structure. Among them, the microstructure includes a micron protrusion structure, a micron recessed structure, etc., and the nanostructure includes nanoparticles, nanoripples, nanosynapses, nanopits, nanoprotrusions, nanogratings, nanohairs, nanowires, nanotubes, nanosheets, nanoflowers, nanograss, etc. This helps to select different processing methods according to the characteristics of the substrate material to realize the micro-nano structure, and at the same time helps to ensure the stable adhesion of the spectrally selective absorption layer on the substrate.

[0065] In some embodiments of the present application, the lateral size of the microstructure is 1 μm to 1000 μm, and the lateral size of the microstructure is the maximum distance between any two points on the contour line of the microstructure close to the surface of the substrate. Specifically, the lateral size of the microstructure can be 1 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm, 1000 μm, etc. As an example, Figure 1 The lateral dimension A of the microstructure is shown. A lateral dimension of the microstructure within the above range helps increase the contact area between the spectrally selective absorption layer, i.e., the aluminum hydroxide powder and boehmite powder, and the substrate, thereby strengthening the bond between the two. This can essentially avoid problems such as excessively large lateral dimensions of the microstructure, which reduces the number of structures per unit area, thereby reducing the actual contact area between the spectrally selective absorption layer and the substrate and making it easy for the spectrally selective absorption layer to fall off the substrate. Problems such as increased difficulty in substrate processing and difficulty for the spectrally selective absorption layer to enter the interior of the microstructure, which may be caused by excessively small lateral dimensions of the microstructure, can also be avoided.

[0066] In some embodiments of the present application, the height of the microstructure is 1 μm to 1000 μm, wherein the height of the microstructure is the maximum distance between the microstructure and the substrate surface in a direction perpendicular to the substrate surface. Specifically, the height of the microstructure can be 1 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm, 1000 μm, etc. As an example, Figure 1The height C of the microstructure is shown. A microstructure height within the above range helps increase the contact area between the spectrally selective absorption layer, i.e., the aluminum hydroxide powder and the boehmite powder, and the substrate, thereby strengthening the bond between the two. This can essentially avoid problems such as excessively high microstructures leading to a decrease in mechanical strength and susceptibility to damage, which in turn increases the processing cost of the microstructure, and excessively low heights leading to insufficient use of the spectrally selective absorption layer, thereby affecting the spectral control performance of the spectrally selective absorption film layer.

[0067] In some embodiments of the present application, the spacing between two adjacent microstructures is 1 μm to 1000 μm, and the spacing between two adjacent microstructures is defined as the shortest distance between the surfaces of the two adjacent microstructures close to the substrate. Specifically, the spacing between two adjacent microstructures can be 1 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm, 1000 μm, etc. As an example, Figure 1 The spacing B between the microstructures is shown. This helps to further enhance the bonding strength of the spectrally selective absorption layer on the substrate, thereby preventing the spectrally selective absorption layer from falling off the substrate.

[0068] In some embodiments of the present application, the size of the nanostructure may be 1 nm to 100 μm, where the size of the nanostructure is the maximum distance between any two points of the nanostructure in any direction, where any direction may include: a direction in which the nanostructure is perpendicular to the substrate or the surface of the microstructure, or a direction in which the nanostructure is close to the surface of the substrate or the microstructure. Specifically, the size of the nanostructure may be 1 nm, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, 1 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, etc. The size of the nanostructure within the above range helps to increase the contact area between the spectrally selective absorption layer, i.e., aluminum hydroxide powder and boehmite powder, and the substrate, making the bond between the two stronger. It can basically avoid the problem that the nanostructure size is too large, resulting in a reduction in the number of structures per unit area, thereby avoiding the actual contact area between the spectrally selective absorption layer and the substrate becoming relatively smaller, making it easy to fall off from the substrate, and the problems such as the increased difficulty in substrate processing due to the small size of the nanostructure and the difficulty for the spectrally selective absorption layer to enter the interior of the nanostructure.

[0069] In a second aspect of the present application, a spectrally selective absorption structure is proposed, comprising:

[0070] A body; the aforementioned spectrally selective absorption film layer, the spectrally selective absorption film layer being disposed on at least a portion of the surface of the body. The spectrally selective absorption structure includes the aforementioned spectrally selective absorption film layer, and thus, the spectrally selective absorption structure possesses all the features and advantages of the aforementioned spectrally selective absorption film layer, which are not further elaborated here.

[0071] In some embodiments of the present application, at least a portion of the body constitutes the substrate in the film layer, and a portion of the body serves as the substrate of the spectrally selective absorption film layer. Specifically, a surface of the body can serve as the substrate in the spectrally selective absorption film layer, and a surface of the body can be directly processed to obtain a micro-nano structure, and then the spectrally selective absorption layer is set in the micro-nano structure. For example: a metal electronic device housing is processed to obtain a substrate with a micro-nano structure, and a material with spectral regulation capability is combined with the substrate to form a stable film layer. The film layer can quickly dissipate the heat generated by the operation of the electronic device in the form of infrared radiation, thereby achieving passive cooling and ensuring stable operation of the equipment. This helps to reduce costs, and the spectrally selective absorption structure can be used on a large scale in related fields.

[0072] The third aspect of the present application provides a method for preparing a spectrally selective absorption film layer, comprising:

[0073] S10: processing at least a portion of the surface of the substrate to form a functional area having a micro-nano structure.

[0074] In this step, different processing methods can be used to process the substrate to obtain a substrate with a micro-nano structure. Specifically, the processing method can be laser processing, mechanical processing, ultrasonic processing, electric discharge processing, dry etching, wet etching, imprinting, template method, 3D printing or photolithography, etc. Since laser processing has higher precision and higher adaptability and can process different materials such as metals and non-metals, the preferred processing method is laser processing.

[0075] In some embodiments of the present application, the wavelength of laser processing is 10nm-20000nm, for example, it can be 10nm, 100nm, 500nm, 1000nm, 5000nm, 10000nm, 15000nm, 20000nm, etc. Therefore, by adjusting the laser processing wavelength within the above range, a micro-nano structure of appropriate size can be obtained, which helps to enhance the combination of the spectrally selective absorption layer and the substrate material, and further enhance the spectral control ability of the spectrally selective absorption film layer.

[0076] In some embodiments of the present application, the power of laser processing is 1mW to 10kW, for example, it can be 1mW, 10mW, 100mW, 1W, 10W, 100W, 1kW, 10kW, etc. Therefore, by adjusting the laser processing power within the above range, a micro-nano structure of appropriate size can be obtained, which not only helps to enhance the combination of the spectrally selective absorption layer and the substrate material, but also helps to enhance the spectral control ability of the spectrally selective absorption film layer.

[0077] In some embodiments of the present application, the pulse width of the laser processing is 1fs to 1s, for example, it can be 1fs, 10fs, 100fs, 200fs, 300fs, 400fs, 500fs, 800fs, 1ps, 2ps, 10ps, 20ps, 1ns, 10ns, 20ns, 100ns, 200ns, 300ns, 400ns, 500ns, 1μs, 1ms, 1s, etc. The pulse width of the laser within the above range is helpful to obtain micro-nano structures of appropriate sizes on the substrate surface of different materials, and by adjusting the pulse width of the laser processing within the above range, flexible control of the size and morphology of the micro-nano structure can be achieved, which not only helps to enhance the combination of the spectrally selective absorption layer and the substrate material, but also helps to enhance the spectral control ability of the spectrally selective absorption film layer.

[0078] S20: coating a spectrally selective absorption material on at least a portion of the functional area, and then successively performing scraping and compacting to form the spectrally selective absorption film layer.

[0079] In this step, the spectrally selective absorption raw material can be provided in the form of dry powder or slurry, and the spectrally selective absorption raw material is coated on the functional area to cover the micro-nano structure, ensuring that the amount of spectrally selective absorption raw material is sufficient, thereby helping to prepare a spectrally selective absorption film layer with excellent spectral selection performance; after the spectrally selective absorption raw material is coated on the functional area, the spectrally selective absorption raw material is scraped and compacted. Specifically, appropriate pressure can be applied by a physical press head or other flattening and compacting tools and devices to make the absorption raw material more fully fill the microstructure gaps and form a good bonding interface with the substrate, thereby optimizing the structural integrity and optical properties of the spectrally selective absorption film.

[0080] In some embodiments of the present application, the slurry includes suspensions, pastes, solutions, emulsions, and the like, and the form of the slurry is not limited here.

[0081] As an example, when the spectrally selective absorbing raw material is provided in the form of a suspension, an inorganic solvent or an organic solvent can be used to prepare the spectrally selective absorbing raw material into a suspension. Specifically, the inorganic solvent can be water, and the organic solvent can be ethanol, acetone, isopropanol, etc.

[0082] A fourth aspect of the present application provides a spectrally selective absorption device comprising the aforementioned spectrally selective absorption film or structure. This spectrally selective absorption device includes the aforementioned spectrally selective absorption film or structure, and thus possesses all the features and advantages of the aforementioned spectrally selective absorption film or structure, which are not further elaborated here.

[0083] Specifically, spectrally selective absorption devices can be optical filters, radiative cooling components, and the like. Specifically, optical filters can utilize spectrally selective absorption films or structures to transmit or absorb light within specific wavelength ranges, thereby filtering out light in the desired spectral band. Radiative cooling components can utilize spectrally selective absorption films or structures to achieve high reflectivity in the ultraviolet to near-infrared bands to reduce solar energy absorption, while simultaneously achieving high emissivity in the mid-infrared band to enhance thermal radiation dissipation, thereby cooling the surface of a material or object.

[0084] The fifth aspect of the present application proposes the application of the aforementioned spectrally selective absorption film layer, the aforementioned spectrally selective absorption structure and the aforementioned spectrally selective absorption device in the fields of passive cooling, radiation cooling, radiation heating, refractory materials, infrared camouflage, infrared detection, etc.

[0085] For example, in the field of passive coolant radiation cooling, the spectrally selective absorption film layer in this application can be applied to building glass and exterior wall coatings. The spectrally selective absorption film layer can reflect infrared and part of the visible light in solar radiation, so that the interior of the building absorbs less heat and achieves passive cooling; or the spectrally selective absorption film layer of this application can be applied to the glass of commercial buildings in hot areas to reduce indoor cooling needs, etc.

[0086] The present application is described below with reference to specific examples. It should be noted that these examples are merely illustrative and do not limit the present application in any way. Where specific techniques or conditions are not specified in the examples, the techniques or conditions described in the literature in the art or in the product instructions shall be followed.

[0087] Example 1

[0088] The spectrally selective absorption film layer is prepared using the preparation method of the spectrally selective absorption film layer of the present application, specifically as follows:

[0089] S10: Pure copper was used as the substrate. The polished pure copper sample was ultrasonically cleaned in anhydrous ethanol for 10 minutes to remove surface contaminants. The sample was then dried with dry nitrogen and used as the substrate.

[0090] Nanosecond laser was used to process the substrate surface. The laser processing wavelength was 1064nm, the pulse width was 150ns, the average power was 70W, the scanning speed (i.e. the relative movement speed of the laser and the sample) was 2500mm / s, the number of scans was 150 times, and the spacing between adjacent microstructures was 250μm.

[0091] S20: evenly coating the surface of the substrate obtained in S10 with boehmite powder having an average particle size of about 1 μm, and performing a flattening and compacting process on the surface of the substrate. The thickness of the boehmite powder is about 350 μm.

[0092] Examples 2 to 12

[0093] Same as Example 1, main differences are shown in Table 1.

[0094] Comparative Example 1

[0095] A certain mass of boehmite powder (average particle size of about 1 μm, purity ≥ 99.5%) was taken and pressed into a sheet with a diameter of about 25 mm and a thickness of about 2.5 mm.

[0096] Comparative Example 2

[0097] A certain mass of aluminum hydroxide powder (average particle size of about 2.5 μm, purity ≥ 99.5%) was taken and pressed into a sheet with a diameter of about 25 mm and a thickness of about 2.5 mm.

[0098] Comparative Examples 3 to 11 are substrates prepared in Examples 1 to 9.

[0099] Test method: Spectral testing was performed using a UV-Vis-NIR spectrophotometer and a Fourier transform infrared spectrometer.

[0100] Test results: The average reflectivity of the spectrally selective absorption films prepared in Examples 1 to 12 and Comparative Examples 1 to 11 is shown in Table 1.

[0101] The scanning electron microscope image of the substrate obtained by nanosecond laser processing in Example 1 is shown in FIG. Figure 2 a, a regularly arranged micro-cone structure is obtained on the surface of pure copper; the scanning electron microscope image of the substrate obtained by femtosecond laser processing in Example 10 is shown in FIG. Figure 2 In b, a regularly arranged micro-cone structure is obtained on the surface of pure copper.

[0102] Examples 1 to 4 are nanosecond laser processing, and the scanning electron microscope images of the substrate obtained by changing the number of scanning times of the laser processing are shown in FIG. Figure 3a, b, c, and d in the figure. It can be seen that after 25 laser scans, the micro-nanostructure formed on the substrate surface is relatively flat, with fewer sharp structures, the overall surface is relatively smooth, and the periodic characteristics of the surface structure are not obvious; after 50 laser scans, the surface structure becomes slightly more obvious, the micro-nanostructure becomes more regular and sharper, forming more prominent micro-cones. Compared with 25 scans, the surface morphology becomes more complex, which helps to improve the adhesion between the powder layer and the substrate; after 100 laser scans, the sharpness of the micro-nanostructure is further enhanced, the width of the microgrooves is further reduced, and a denser and more symmetrical micro-cone structure appears on the surface, showing good periodic characteristics; after 150 laser scans, the surface microstructure becomes denser and more regular, the micro-cones are sharper, and a dense periodic microstructure is formed.

[0103] Examples 5 to 8 are nanosecond laser processing, and the SEM images of the substrates obtained by changing the spacing between adjacent micron structures are shown in FIG. Figure 4 As can be seen in a, b, c, and d, at a spacing of 150 μm, the substrate surface exhibits a dense and regular microcone structure; when the spacing increases to 200 μm, the surface microcone structure becomes loose; as the spacing further increases (250 μm and 300 μm), the spacing between microcones increases significantly, and the surface exhibits a more open structure, showing larger inter-cone gaps.

[0104] The spectral selectivity of the spectrally selective absorption films prepared in Example 9 and Example 11 was tested using an ultraviolet-visible-near infrared spectrophotometer. The test results are shown in Figure 5 ;

[0105] The spectral selectivity of the spectrally selective absorption films prepared in Example 1 and Example 10 was tested using an ultraviolet-visible-near infrared spectrophotometer. The test results are shown in Figure 6 ;

[0106] The spectrum selectivity of the spectrally selective absorption film layers prepared in Example 9 and Example 11 was tested using a Fourier transform infrared spectrometer. The test results are shown in the figure. Figure 7 ;

[0107] The spectral selectivity of the spectrally selective absorption film layers prepared in Example 1 and Example 10 was tested using a Fourier transform infrared spectrometer. The test results are shown in the figure. Figure 8 ;

[0108] from Figures 5 to 8It can be seen that the four samples of Example 1 and Examples 9 to 11 all have significant spectrally selective absorption properties, with high reflectivity in the ultraviolet-visible-near-infrared band and high emissivity (i.e., very low reflectivity) in the mid-infrared band. Specifically, the substrate surface processed by nanosecond laser has a stronger spectrally selective absorption effect than the substrate surface processed by femtosecond laser. Comparing the coating of aluminum hydroxide powder on the nanosecond laser-processed substrate surface (Example 1) with the coating of boehmite powder on the nanosecond laser-processed substrate surface (Example 11), the former has a higher mid-infrared emissivity, while the latter has a higher ultraviolet-visible-near-infrared reflectivity.

[0109] The spectral selectivity of the spectrally selective absorption film layers prepared in Examples 1 to 4 was tested using an ultraviolet-visible-near infrared spectrophotometer. The test results are shown in Figure 9 ;

[0110] The spectrum selectivity of the spectrally selective absorption film prepared in Examples 1 to 4 was tested using a Fourier transform infrared spectrometer. The test results are shown in the figure. Figure 10 ;

[0111] from Figures 9 and 10 It can be seen that appropriately increasing the number of laser scans is beneficial to improving the reflectivity of the substrate surface in the ultraviolet-visible-near-infrared band and the emissivity in the mid-infrared band, thereby enhancing its spectrally selective absorption characteristics.

[0112] The spectral selectivity of the spectrally selective absorption film layers prepared in Examples 5 to 8 was tested using an ultraviolet-visible-near infrared spectrophotometer. The test results are shown in Figure 11 ;

[0113] The spectrum selectivity of the spectrally selective absorption film layers prepared in Examples 5 to 8 was tested using a Fourier transform infrared spectrometer. The test results are shown in the figure. Figure 12 ;

[0114] from Figures 11 and 12 As can be seen, in the ultraviolet-visible-near-infrared band (0.25-2.5 μm), as the spacing between adjacent microcones increases from 150 μm to 300 μm, the reflectivity of the spectrally selective absorption surface gradually increases to over 90% and stabilizes. In the mid-infrared band (2.5-25 μm), the reflectivities of the four samples are very similar, all below 10% (i.e., emissivity is above 90%), demonstrating good infrared radiation properties. The research results indicate that by varying the spacing of the substrate surface microstructures, the substrate surface's reflectivity in the ultraviolet-visible-near-infrared band (to over 90%) and emissivity in the mid-infrared band (to over 90%) can be increased, thereby enhancing its spectrally selective absorption properties.

[0115] The spectral selectivity test of the samples prepared in Comparative Examples 1 and 2 was carried out using a Fourier transform infrared spectrometer. The test range was 2.5-25 μm, and the reflectivity curve was used to analyze the reflectivity characteristics in the mid-infrared band. The test results are shown in Figure 13 It can be seen that the aluminum hydroxide powder tablets have obvious characteristic absorption peaks in the mid-infrared band, and the reflectivity is low in the 8-15μm atmospheric window range, showing strong infrared radiation ability (i.e., high infrared emissivity); the reflectivity curve of the boehmite powder tablets is relatively flat, and it shows low reflectivity in the entire 2.5-25μm range, which means that it has stable and efficient infrared emission capabilities in the mid-infrared band. However, since the sheet samples pressed by aluminum hydroxide powder and boehmite powder have very low strength and are easily broken into powder, it is impossible to test their reflectance spectra in the ultraviolet-visible-near infrared bands, indicating that aluminum hydroxide and boehmite powders cannot be directly used as spectrally selective absorption surfaces.

[0116] Table 1

[0117]

[0118]

[0119] Conclusion: The spectrally selective absorption film layer obtained by this application has a relatively high reflectivity in the ultraviolet-visible-near infrared band (0.25μm~2.5μm), especially in the visible light band (400nm~800nm), while the reflectivity in the mid-infrared band (2.5μm~25μm) is generally low. Therefore, the spectrally selective absorption film layer has excellent infrared high emission and spectrally selective absorption properties.

[0120] In the description of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of such features. In the description of this application, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0121] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0122] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A spectrally selective absorption film layer, characterized in that: include: A substrate, wherein the surface of the substrate has a functional area, and the functional area has a micro-nano structure; A spectrally selective absorption layer is provided on the surface of the substrate and is located in the functional area. The spectrally selective absorption layer includes at least one of aluminum hydroxide powder and boehmite powder.

2. The spectrally selective absorption film layer according to claim 1, characterized in that: The spectrally selective absorption layer is composed of at least one of aluminum hydroxide powder and boehmite powder.

3. The spectrally selective absorption film layer according to claim 1, characterized in that: Meet at least one of the following conditions: The particle size of the aluminum hydroxide powder is 0.01 μm to 100 μm; The particle size of the boehmite powder is 0.01 μm to 100 μm.

4. The spectrally selective absorption film layer according to claim 1, characterized in that: The thickness of the spectrally selective absorption layer is 1 μm to 1000 μm.

5. The spectrally selective absorption film layer according to claim 1, characterized in that: The substrate includes at least one of metal materials, ceramic materials, semiconductor materials, and polymer materials.

6. The spectrally selective absorption film layer according to claim 5, characterized in that: Meet at least one of the following conditions: The metal material includes at least one of gold, silver, platinum, aluminum, aluminum alloy, magnesium, magnesium alloy, zinc, zinc alloy, copper, copper alloy, titanium, titanium alloy, tungsten, tungsten alloy, nickel, nickel alloy, manganese, manganese alloy, iron, and steel; The ceramic material includes at least one of aluminum oxide, zirconium oxide, silicon oxide, silicon nitride, silicon carbide, boron nitride, boron carbide, aluminum nitride, titanium nitride, barium titanate, lithium niobate, lithium tantalate, titanium oxide, magnesium oxide, zinc oxide, vanadium oxide, tin oxide, hydroxyapatite, silicate glass, and oxynitride ceramics; The semiconductor material includes at least one of silicon, germanium, gallium arsenide, gallium oxide, gallium nitride, cadmium telluride, zinc oxide, zinc selenide, silicon carbide, indium phosphide, and diamond; The polymer material includes at least one of polydimethylsiloxane, polyethylene terephthalate, polycarbonate, polymethyl methacrylate, polyimide, polytetrafluoroethylene, polystyrene, polyethylene, polypropylene, polyamide, polyurethane, and photoresist.

7. The spectrally selective absorption film layer according to claim 1, characterized in that: The micro-nano structure includes a microstructure and / or a nanostructure, and the nanostructure is located on the surface of the substrate or the microstructure; Wherein, the micron structure includes at least one of a micron protruding structure and a micron recessed structure; The nanostructure includes at least one of nanoparticles, nanoripples, nanosynapses, nanopits, nanoprotrusions, nanogratings, nanohairs, nanowires, nanotubes, nanosheets, nanoflowers, and nanograss.

8. The spectrally selective absorption film layer according to claim 7, characterized in that: The lateral size of the microstructure is 1 μm to 1000 μm, the height of the microstructure is 1 μm to 1000 μm, and the spacing between two adjacent microstructures is 1 μm to 1000 μm; The lateral dimension of the microstructure is the maximum distance between any two points on the contour line of the microstructure close to the surface of the substrate; The height of the microstructure is the maximum distance between the microstructure and the substrate surface in a direction perpendicular to the substrate surface; The spacing between two adjacent microstructures is the shortest distance between the surfaces of the two adjacent microstructures close to the substrate.

9. A spectrally selective absorption structure, characterized in that: include: ontology; The spectrally selective absorption film layer according to any one of claims 1 to 8, wherein the spectrally selective absorption film layer is provided on at least a portion of the surface of the body.

10. The spectrally selective absorption structure according to claim 9, characterized in that: At least a portion of the body constitutes a base in the spectrally selective absorption film layer.

11. A method for preparing a spectrally selective absorption film layer, characterized in that: include: Processing at least a portion of the surface of the substrate to form a functional area having a micro-nano structure; The spectrally selective absorption material is coated on at least a portion of the functional area, and is subsequently scraped and compacted to form the spectrally selective absorption film layer.

12. The method for preparing a spectrally selective absorption film layer according to claim 11, characterized in that: The processing of at least a portion of the surface of the substrate includes at least one of laser processing, mechanical processing, ultrasonic processing, electric discharge processing, dry etching, wet etching, imprinting, template method, 3D printing, and photolithography. Preferably, the processing is laser processing.

13. The method for preparing a spectrally selective absorption film layer according to claim 12, characterized in that: The laser processing satisfies at least one of the following conditions: The wavelength of the laser processing is 10nm to 20000nm; The power of the laser processing is 1mW to 10kW; The pulse width of the laser processing is 1 fs to 1 s.

14. The method for preparing a spectrally selective absorption film layer according to claim 11, characterized in that: The spectrally selective absorption raw material is provided in the form of dry powder and / or slurry.

15. A spectrally selective absorption device, characterized in that: The invention comprises the spectrally selective absorption film layer according to any one of claims 1 to 8 or the spectrally selective absorption structure according to claims 9 to 10.

16. Application of the spectrally selective absorption film layer according to any one of claims 1 to 8, the spectrally selective absorption structure according to claims 9 to 10, or the spectrally selective absorption device according to claim 15 in the fields of passive cooling, radiation cooling, radiation heating, refractory materials, infrared camouflage, and infrared detection.

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