Daytime radiant cooling glass and method of making and use thereof

Abstract

The present application relates to the technical field of energy-saving materials, and particularly relates to a daytime radiative cooling glass, a preparation method and application thereof. The daytime radiative cooling glass is provided with a grating on the surface of the glass, and a porous scattering layer is arranged below the grating, and the porous scattering layer comprises micropores and nanopores. In the present application, the surface of the glass is irradiated by laser, and then the surface microstructure and the porous reflection layer are obtained through chemical corrosion. The grating structure effectively reduces the phonon-polaron vibration reflection of SiO2 in the glass, and improves the surface emissivity; the porous reflection layer effectively reflects sunlight. Compared with the traditional daytime radiative cooling material, the daytime radiative cooling glass provided by the present application has excellent weather resistance, and can continuously play a cooling role in the complex outdoor environment.

Description

Technical Field

[0001] This invention relates to the field of energy-saving materials technology, specifically to a daytime radiation cooling glass, its preparation method, and its application. Background Technology

[0002] Daytime radiative cooling materials are a class of excellent passive cooling materials. They exhibit high reflectivity and low absorption in the solar spectrum, and high emissivity in the mid-infrared spectrum, especially in the atmospheric window (8μm–13μm). The material surface can achieve a cooling effect below ambient temperature, and has been widely researched and applied in energy-efficient buildings and transportation facilities in recent years. They mainly include two structural types: porous structures and metal-layered high-emissivity surface structures. Porous structures utilize the difference in refractive index between the material and air to cause solar scattering and reflection. Simultaneously, due to the intrinsic properties and porous characteristics of the material, they exhibit high emissivity in the mid-infrared band. For example, the P(VdF-HFP)HP film with a hierarchical porous structure prepared by Yu et al. (Science 362, 2018, 315–319) achieved a solar reflectivity of 0.96 and a mid-infrared emissivity of 0.97 at 890 W·m⁻¹. -2 Under certain irradiation intensities, porous membranes can achieve a cooling effect of 6°C below room temperature. Invention patent CN113025133B combines hydrophobically modified inorganic nanoparticles with organic resin, utilizing the resin curing process during solvent evaporation to obtain a superhydrophobic porous membrane, achieving excellent radiative cooling. However, in practical applications, such materials based on organic resins face challenges in weather resistance under complex outdoor environments, and their porous nature also results in low mechanical strength.

[0003] A metal layer with a high surface emissivity structure is used to achieve low absorption of the solar spectrum by reflecting light through the metal layer. Simultaneously, the high-emissivity layer covering the metal layer continuously radiates heat into the low-temperature universe, achieving passive cooling. Silver is commonly chosen as the metal. For example, Fan et al. (Nature 515, 2014, 540-544) prepared a structure with several alternating SiO2 / HfO2 layers covering a silver layer using electron beam evaporation. This structure reflects 97% of sunlight and exhibits high emissivity in the atmospheric window band (8–13 μm), reaching 850 W·m⁻¹. -2 Under certain irradiation intensities, a metal-multilayer film structure can achieve a cooling effect 4.9°C below room temperature. Invention patent CN110274326B describes a structure fabricated on glass using electron beam evaporation, with a silver layer as the lower layer and alternating SiO2 / TiO2…-MgF2 / ZnS layers as the upper layer, resulting in a radiation cooling device with a solar reflectivity greater than 96% and an emissivity close to 1 in the 8–13 μm range. However, in practical applications, the protection of the metal layer and the manufacturing cost of the multilayer film need to be considered, and the structure also faces the problem of poor weather resistance. Summary of the Invention

[0004] The purpose of this invention is to provide a daytime radiative cooling material with high weather resistance and low manufacturing cost. It is a glass material with high solar reflectivity and high emissivity that achieves daytime radiative cooling performance. Compared with polymer materials and silver-containing multilayer film materials, it has excellent outdoor weather resistance and cost advantages.

[0005] The first aspect of the present invention provides a daytime radiation-cooled glass, wherein a grating is provided on the surface of the glass, and a porous scattering layer is provided below the grating, the porous scattering layer including micron-pores and nano-pores.

[0006] Preferably, the spacing of the grating in A1) is 1 to 10 μm, for example, it can be 1 to 2 μm, 2 to 3 μm, 3 to 4 μm, 4 to 5 μm, 5 to 6 μm, 6 to 7 μm, 7 to 8 μm, 8 to 9 μm, 9 to 10 μm, etc. The spacing of the grating refers to the distance between two adjacent protrusions.

[0007] Preferably, the width of the grating in A2) is 1 to 10 μm, for example, it can be 1 to 2 μm, 2 to 3 μm, 3 to 4 μm, 4 to 5 μm, 5 to 6 μm, 6 to 7 μm, 7 to 8 μm, 8 to 9 μm, or 9 to 10 μm.

[0008] Preferably, the height of the grating in A3) is 1 to 10 μm, for example, it can be 1 to 2 μm, 2 to 3 μm, 3 to 4 μm, 4 to 5 μm, 5 to 6 μm, 6 to 7 μm, 7 to 8 μm, 8 to 9 μm, 9 to 10 μm, etc., to reflect the ultraviolet and short-wave visible light bands in the solar spectrum;

[0009] Preferably, the pore size of the micron-sized pore (A4) is 1–8 μm, for example, it can be 1–2 μm, 2–3 μm, 3–4 μm, 4–5 μm, 5–6 μm, 6–7 μm, 7–8 μm, etc.

[0010] Preferably, the pore size of the nanopores described in A5) is 50-500 nm, for example, it can be 50-100 nm, 100-150 nm, 150-200 nm, 200-250 nm, 250-300 nm, 300-350 nm, 350-400 nm, 400-450 nm, 450-500 nm, etc., reflecting the ultraviolet and short-wave visible light bands in the solar spectrum.

[0011] Preferably, the spectral modulation of the daytime radiation-cooled glass is selected from one or more of the 0.3–2.5 μm sunlight and 8–13 μm mid-infrared light bands.

[0012] Preferably, the daytime radiation cooling glass described in B1) has a reflectivity of >90% for 0.3–2.5 μm sunlight, and more preferably, the daytime radiation cooling glass has a reflectivity of 90%–98% for 0.3–2.5 μm sunlight;

[0013] Preferably, the emissivity of the daytime radiation cooling glass in the 8-13μm mid-infrared band is >0.9; more preferably, the emissivity of the daytime radiation cooling glass in the 8-13μm mid-infrared band is 0.9-0.98.

[0014] The second aspect of the present invention provides a method for preparing the above-mentioned daytime radiation-cooled glass, comprising irradiating the glass with a laser, and then sequentially performing acid etching and alkaline etching to obtain the daytime radiation-cooled glass.

[0015] This invention first performs a first laser irradiation treatment. To ensure the porous glass surface formed by etching has a certain strength and to achieve an ideal sunlight reflection effect, the porous layer adopts a discontinuous multi-layer layout. Pulsed lasers irradiate the glass surface in a point-like pattern with different focal lengths. The laser power is adjusted to ensure that the irradiated area of ​​the glass exceeds its optical damage threshold without ablating the glass. The glass material in the focal area is modified, and its corrosion rate by acid or alkali aqueous solutions is 30 to 50 times that of the non-irradiated area. In the subsequent selective etching process, a porous scattering layer is formed. Then, a second laser irradiation is performed, with linear irradiation of the glass surface at a certain power and focal length according to the designed spacing. After laser irradiation, a glass blank is formed.

[0016] After laser irradiation, the glass surface exhibits differences in its resistance to acid and alkali etching, with the irradiated area showing a faster corrosion rate. Hydrofluoric acid etching of glass results in a relatively strong reaction, forming micropores and surface grating structures through acid etching; the reaction between alkali and glass is relatively mild, serving as a supplementary finishing etching process after acid etching and forming nanopores.

[0017] Preferably, the glass described in C1) is silicate glass;

[0018] Preferably, C2) the laser irradiation includes a first laser irradiation;

[0019] Preferably, the acid used for etching in C3) is selected from one or more of HF, HCl, H2SO4 and HNO3;

[0020] Preferably, the acid etching temperature of C4) is 20-50°C, to obtain a glass with a micron-sized porous layer and a surface grating structure.

[0021] Preferably, the alkali used for alkaline etching in C5) is selected from one or more of KOH, NaOH, LiOH and NH3·H2O;

[0022] Preferably, the alkaline etching temperature of C6) is 40-95°C to obtain a glass with a porous layer having nanopores.

[0023] Preferably, in feature C1), the silicate glass is selected from one or more of soda-lime glass, aluminosilicate glass, and borosilicate glass;

[0024] Preferably, in feature C2), the laser irradiated by the first laser is selected from one or more of millisecond, microsecond, and nanosecond lasers;

[0025] Preferably, in feature C2), the linear spacing of the laser beam irradiated by the first laser is 1 to 5 mm, for example, it can be 1 to 2 mm, 2 to 3 mm, 3 to 4 mm, 4 to 5 mm, etc.

[0026] Preferably, in feature C2), the power of the first laser irradiation is 10 to 1000W, for example, it can be 10 to 100W, 100 to 200W, 200 to 300W, 300 to 400W, 400 to 500W, 500 to 600W, 600 to 700W, 700 to 800W, 800 to 900W, 900 to 1000W, etc.

[0027] Preferably, in feature C2), the center wavelength of the first laser irradiation is selected from one or more of 980nm, 1053nm, and 1064nm;

[0028] Preferably, in feature C2), the pulse width of the first laser irradiation is 1.5-2 mm and is 20 nanoseconds to 5 milliseconds;

[0029] Preferably, in feature C2), the beam size of the first laser irradiation is 0.1 to 3 mm, for example, it can be 0.1 to 0.5 mm, 0.5 to 1 mm, 1 to 1.5 mm, 2 to 2.5 mm, 2.5 to 3 mm, etc.

[0030] Preferably, in feature C2), the laser focal point of the first laser irradiation is 5-15 μm away from the glass surface, for example, it can be 5-6 μm, 6-7 μm, 7-8 μm, 8-9 μm, 9-10 μm, 10-11 μm, 11-12 μm, 12-13 μm, 13-14 μm, 14-15 μm, etc.

[0031] Preferably, in feature C2), the scanning speed of the first laser irradiation is 0.05 to 2 m / s;

[0032] Preferably, in feature C2), the line spacing of the first laser irradiation scan is 0.1–3 mm;

[0033] Preferably, in characteristic C3), the aqueous solution of the acid has a mass concentration of 0.1 to 5.0 wt%.

[0034] Preferably, in characteristic C5), the aqueous solution of the alkali has a mass concentration of 0.1 to 5.0 wt%.

[0035] Preferably, the laser irradiation includes a second laser irradiation.

[0036] Preferably, D1) the laser used for the second laser irradiation is selected from one or more of nanosecond, picosecond, and femtosecond lasers;

[0037] Preferably, in D2), the power of the second laser irradiation is 50-1000W, for example, it can be 50-100W, 100-200W, 200-300W, 300-400W, 400-500W, 500-600W, 600-700W, 700-800W, 800-900W, 900-1000W, etc.

[0038] Preferably, (D3) the center wavelength of the second laser irradiation is selected from one or more of 532nm, 660nm, 980nm and 1064nm;

[0039] Preferably, in D4), the pulse width of the second laser irradiation is 100 femtoseconds to 5 nanoseconds;

[0040] Preferably, the minimum beam size of the second laser irradiation (D5) is 3-20 μm, 3-5 μm, 5-10 μm, 10-15 μm, 15-20 μm, etc.

[0041] Preferably, in D6), the laser focal point of the second laser irradiation is 5-10 μm away from the glass surface, for example, it can be 5-6 μm, 6-7 μm, 7-8 μm, 8-9 μm, 9-10 μm, etc.

[0042] Preferably, the scanning speed of the second laser irradiation (D7) is 0.1 to 1 m / s, for example, it can be 0.1 to 0.4 m / s, 0.4 to 0.6 m / s, 0.6 to 0.8 m / s, 0.8 to 1 m / s, etc.

[0043] Preferably, the line spacing of the second laser irradiation scan (D8) is 0.01 to 0.02 mm.

[0044] The third aspect of the present invention provides an application of daytime radiation cooling glass, which is used for passive cooling of buildings, heat dissipation and cooling in the fields of power and transportation.

[0045] The present invention has the following beneficial effects:

[0046] 1) This invention employs laser irradiation to treat the glass surface, followed by chemical etching to obtain surface microstructures and a porous reflective layer. The grating structure effectively reduces the reflection of phonon-polaron vibrations in SiO2 within the glass, thereby increasing surface emissivity; the porous reflective layer effectively reflects sunlight, resulting in daytime radiation-cooled glass with high solar reflectivity and high emissivity. Compared to traditional daytime radiation-cooling materials, the daytime radiation-cooled glass provided by this invention exhibits excellent weather resistance and can sustainably provide cooling in complex outdoor environments.

[0047] 2) This invention uses a preparation method suitable for large-scale industrial application to obtain daytime radiation cooling materials, which better meets market demand and provides alternative heat dissipation and cooling materials for energy-saving buildings, power, transportation and other fields. Attached Figure Description

[0048] Figure 1 These are schematic diagrams of the surface structure of the daytime radiation cooling glass in Embodiments 1-4 of the present invention; reference numeral 1 refers to the grating, and reference numeral 2 refers to the porous scattering layer;

[0049] Figure 2 The transmittance-reflectance curves are those of the daytime radiation cooling glass in embodiments 4 and 10 of the present invention.

[0050] Figure 3 The mid-infrared emissivity curves are for the daytime radiation cooling glass in Examples 1-4 of this invention. Detailed Implementation

[0051] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0052] Please see Figures 1 to 3 It should be understood that the structures, proportions, sizes, etc., illustrated in the accompanying drawings are merely for illustrative purposes to aid those skilled in the art and to facilitate understanding. They are not intended to limit the scope of the invention and therefore have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness and objectives of the invention, should still fall within the scope of the technical content disclosed herein. Furthermore, the terms such as "upper," "lower," "left," "right," "middle," and "one" used in this specification are merely for clarity and not intended to limit the scope of the invention or alter its relative relationships.

[0053] Unless otherwise specified, all reagents, glass raw materials, and instruments used in the following embodiments are commercially available.

[0054] Example 1

[0055] 1) Using 2mm thick soda-lime glass, the glass is first subjected to a millisecond laser irradiation treatment. The pulsed laser parameters are: center wavelength 1064nm, pulse width 5ms, minimum beam size 2mm, and laser focus located about 10μm below the glass surface. The glass is irradiated line by line along a straight line at a scanning speed of 0.4m / s with a line spacing of about 2mm to obtain a porous pretreatment layer with a dotted distribution.

[0056] 2) The surface grating structure is subjected to a second laser irradiation treatment using a picosecond laser. The pulsed laser parameters are: center wavelength 1064nm, pulse width 100 picoseconds, minimum spot size 20μm, laser focus located about 5μm below the glass surface, and the glass is irradiated line by line along a straight line at a scanning speed of 0.5m / s with a line spacing of about 0.02mm to obtain the surface grating structure pretreatment layer.

[0057] 3) The laser-pretreated glass was placed in an acid etching solution for chemical etching. The etching solution was HF 0.2wt%, and the etching was carried out at 50°C for 16 hours.

[0058] 4) The acid-etched glass is placed in an alkaline etching solution, which is a KOH solution with a KOH concentration of 0.5 wt%. The glass is etched at 90°C for 20 hours, then removed, cleaned, and dried to obtain a daytime radiation cooling glass with a grating structure on the surface and a porous scattering layer below the grating structure. The glass has a solar reflectivity (0.3~2.4μm) of 0.9 and a mid-infrared emissivity of 0.91.

[0059] Example 2

[0060] 1) Using 2mm thick aluminosilicate glass, the glass is first treated with nanosecond laser irradiation. The pulsed laser parameters are: center wavelength 532nm, pulse width 20 nanoseconds, minimum beam size 1mm, laser focus located about 10μm below the glass surface, and the glass is irradiated along a straight line at a scanning speed of 1m / s with a line spacing of about 1mm to obtain a porous pretreatment layer with a pulse dot distribution.

[0061] 2) A femtosecond laser is used to perform a second laser irradiation treatment on the surface grating structure. The pulsed laser parameters are: center wavelength 800nm, pulse width 120 femtoseconds, minimum beam size 8μm, and laser focus located about 7μm below the glass surface. The glass is irradiated line by line along a straight line at a scanning speed of 0.5m / s with a line spacing of about 0.01mm to obtain the surface grating structure pretreatment layer.

[0062] 3) The laser-pretreated glass was placed in an acid etching solution for chemical etching. The etching solution consisted of 0.2 wt% HF, 0.1 wt% H2SO4, and 0.1 wt% HNO3. The etching was carried out at 50°C for 16 hours.

[0063] 4) The acid-etched glass is placed in an alkaline etching solution, which is a KOH solution with a KOH concentration of 0.5 wt%. The glass is etched at 90°C for 24 hours, then removed, cleaned, and dried to obtain a daytime radiation cooling glass with a grating structure on the surface and a porous scattering layer below the grating structure. The glass has a solar reflectivity (0.3~2.4μm) of 0.9 and a mid-infrared emissivity of 0.945.

[0064] Example 3

[0065] 1) Using 2mm thick high borosilicate glass, the glass is first treated with millisecond laser irradiation. The pulsed laser parameters are: center wavelength 1064nm, pulse width 5ms, minimum beam size 2mm, and laser focus located about 10μm below the glass surface. The glass is irradiated line by line along a straight line at a scanning speed of 0.5m / s with a line spacing of about 2mm to obtain a porous pretreatment layer with pulsed dot distribution.

[0066] 2) The surface grating structure is subjected to a second laser irradiation treatment using a picosecond laser. The pulsed laser parameters are: center wavelength 800nm, pulse width 120 picoseconds, minimum spot size 8μm, laser focus located about 5μm below the glass surface, and the glass is irradiated line by line along a straight line at a scanning speed of 0.5m / s with a line spacing of about 0.015mm to obtain the surface grating structure pretreatment layer.

[0067] 3) The laser-pretreated glass was placed in an acid etching solution for chemical etching. The etching solution was HF 1.0wt%, and the etching was carried out at 25°C for 15 hours.

[0068] 4) The acid-etched glass is placed in an alkaline etching solution, which is a NaOH solution with a NaOH concentration of 1.0 wt%. The glass is etched at 95°C for 10 hours, then removed, cleaned, and dried to obtain a daytime radiation cooling glass with a grating structure on the surface and a porous scattering layer below the grating structure. The glass has a solar reflectivity (0.3~2.4μm) of 0.9 and a mid-infrared emissivity of 0.93.

[0069] Example 4

[0070] 1) Using 2mm thick ultra-white soda-lime glass, the glass is first treated with nanosecond laser irradiation. The pulsed laser parameters are: center wavelength 532nm, pulse width 20 nanoseconds, minimum beam size 1mm, laser focus located about 10μm below the glass surface, and the glass is irradiated in a straight line at a scanning speed of 1m / s with a line spacing of about 1mm to obtain a porous pretreatment layer with a pulse dot distribution.

[0071] 2) A femtosecond laser is used to perform a second laser irradiation treatment on the surface grating structure. The pulsed laser parameters are: center wavelength 800nm, pulse width 120 femtoseconds, minimum beam size 8μm, and laser focus located about 7μm below the glass surface. The glass is irradiated line by line along a straight line at a scanning speed of 0.5m / s with a line spacing of about 0.01mm to obtain the surface grating structure pretreatment layer.

[0072] 3) The laser-pretreated glass was placed in an acid etching solution for chemical etching. The etching solution was HF 0.2wt.%, and the etching was carried out at 50°C for 16 hours.

[0073] 4) Immerse the acid-etched glass in an alkaline etching solution (KOH solution, 0.5 wt%) at 90°C for 24 hours. Remove, clean, and dry to obtain a daytime radiation-cooled glass with a grating structure on the surface and a porous scattering layer beneath it. The transmittance and reflectance curves of sunlight (0.3–2.4 μm) are shown in the attached figure. Figure 2 As shown in the attached figure, the mid-infrared emissivity curve is... Figure 3 As shown, the reflectivity is 0.91 and the emissivity is 0.94.

[0074] Example 5

[0075] 1) Using 2mm thick soda-lime glass, the glass is first subjected to a millisecond laser irradiation treatment. The pulsed laser parameters are: center wavelength 1064nm, pulse width 5ms, minimum beam size 2mm, and laser focus located about 10μm below the glass surface. The glass is irradiated line by line along a straight line at a scanning speed of 0.4m / s with a line spacing of about 2mm to obtain a porous pretreatment layer with a dotted distribution.

[0076] 2) A second laser irradiation treatment of the surface grating structure is performed using a millisecond laser. The pulsed laser parameters are: center wavelength 1064nm, pulse width 5ms, minimum spot size 1μm, and laser focus located about 5μm below the glass surface. The glass is irradiated line by line along a straight line at a scanning speed of 0.5m / s with a line spacing of about 1mm to obtain the surface grating structure pretreatment layer.

[0077] 3) The laser-pretreated glass was placed in an acid etching solution for chemical etching. The etching solution was HF 2.0wt%, and the etching was carried out at 50°C for 16 hours.

[0078] 4) The acid-etched glass is placed in an alkaline etching solution, which is a KOH solution with a KOH concentration of 5.0 wt%. The glass is etched at 90°C for 20 hours, then removed, cleaned, and dried to obtain a daytime radiation cooling glass with a grating structure on the surface and a porous scattering layer below the grating structure. The glass has a solar reflectivity (0.3~2.4μm) of 0.92 and a mid-infrared emissivity of 0.88.

[0079] Example 6

[0080] 1) Using 2mm thick ultra-white soda-lime glass, the glass is first treated with nanosecond laser irradiation. The pulsed laser parameters are: center wavelength 980nm, pulse width 20 nanoseconds, minimum beam size 1mm, laser focus located about 10μm below the glass surface, and the glass is irradiated along a straight line at a scanning speed of 1m / s with a line spacing of about 1mm to obtain a porous pretreatment layer with a pulse dot distribution.

[0081] 2) A femtosecond laser was used to perform a second laser irradiation treatment on the surface grating structure. The pulsed laser parameters were: center wavelength 980 nm, pulse width 120 femtoseconds, minimum spot size 8 μm, and laser focus located approximately 7 μm below the glass surface. The glass was irradiated line by line along a straight line at a scanning speed of 0.5 m / s, with a line spacing of approximately 0.01 mm, to obtain the surface grating structure pretreatment layer. 3) The laser-pretreated glass was then placed in an acid etching solution (HF 0.5 wt%) for chemical etching at 40°C for 10 hours.

[0082] 4) The acid-etched glass is placed in an alkaline etching solution, which is a KOH solution with a KOH concentration of 0.5 wt%. The glass is etched at 80°C for 20 hours, then removed, cleaned, and dried to obtain a daytime radiation cooling glass with a grating structure on the surface and a porous scattering layer below the grating structure. The glass has a solar reflectivity (0.3~2.4μm) of 0.915 and a mid-infrared emissivity of 0.938.

[0083] Example 7

[0084] 1) Using 2mm thick ultra-white soda-lime glass, the glass is first treated with nanosecond laser irradiation. The pulsed laser parameters are: center wavelength 532nm, pulse width 20 nanoseconds, minimum beam size 1mm, and laser focus located about 6μm below the glass surface. The glass is irradiated in a straight line at a scanning speed of 1m / s, first scanning laterally and then longitudinally, with a line interval of about 1mm, to obtain a porous pre-treatment layer with a pulse dot distribution.

[0085] 2) A femtosecond laser is used to perform a second laser irradiation treatment on the surface grating structure. The pulsed laser parameters are: center wavelength 800nm, pulse width 120 femtoseconds, minimum beam size 8μm, and laser focus located about 3μm below the glass surface. The glass is irradiated line by line along a straight line at a scanning speed of 0.5m / s with a line spacing of about 0.01mm to obtain the surface grating structure pretreatment layer.

[0086] 3) The laser-pretreated glass was placed in an acid etching solution for chemical etching. The etching solution was HF 0.2wt%, and the etching was carried out at 25°C for 20 hours.

[0087] 4) The acid-etched glass is placed in an alkaline etching solution, which is a KOH solution with a KOH concentration of 0.5 wt%. The glass is etched at 90°C for 24 hours, then removed, cleaned, and dried to obtain a daytime radiation cooling glass with a grating structure on the surface and a porous scattering layer below the grating structure. The glass has a solar reflectivity of 0.76 and a mid-infrared emissivity of 0.87.

[0088] Example 8

[0089] 1) 2mm thick ultra-white soda-lime glass is used, which is irradiated with picosecond laser. The pulse laser parameters are: center wavelength 1064nm, pulse width 100 picoseconds, minimum beam size 15μm, laser focus located about 5μm below the glass surface, and the glass is irradiated line by line along a straight line at a scanning speed of 1m / s with a line spacing of about 0.02mm. Pretreatment layer.

[0090] 2) The laser-pretreated glass was placed in an acid etching solution for chemical etching. The etching solution was HF 0.2wt%, and the etching was carried out at 25°C for 20 hours.

[0091] 3) The acid-etched glass is placed in an alkaline etching solution, which is a KOH solution with a KOH concentration of 0.5wt%. The glass is etched at 90℃ for 24 hours, then removed, cleaned, and dried to obtain a daytime radiation cooling glass with a grating structure on the surface and a porous scattering layer below the grating structure. The glass has a solar reflectivity of 0.46 and a mid-infrared emissivity of 0.89.

[0092] Example 9

[0093] 1) Using 2mm thick ultra-white soda-lime glass, the glass is first treated with millisecond laser irradiation. The pulsed laser parameters are: center wavelength 1064nm, pulse width 2ms, minimum beam size 2mm, laser focus located about 10μm below the glass surface, and the glass is irradiated along a straight line at a scanning speed of 1m / s with a line spacing of about 1mm to obtain a porous pre-treatment layer with a pulse dot distribution.

[0094] 2) Perform a longitudinal scan with the same parameters, with the laser focus located 15 μm below the glass surface;

[0095] 3) A femtosecond laser is used to perform a second laser irradiation treatment on the surface grating structure. The pulsed laser parameters are: center wavelength 800nm, pulse width 120 femtoseconds, minimum beam size 8μm, and laser focus located about 7μm below the glass surface. The glass is irradiated line by line along a straight line at a scanning speed of 0.5m / s with a line spacing of about 0.01mm to obtain the surface grating structure pretreatment layer.

[0096] 4) The laser-pretreated glass is placed in an acid etching solution for chemical etching. The etching solution is 0.2 wt% HF, and the etching is carried out at 25°C for 20 hours.

[0097] 5) Immerse the acid-etched glass in an alkaline etching solution (KOH solution, 0.5 wt%) at 90°C for 24 hours. Remove, clean, and dry to obtain a daytime radiation-cooled glass with a grating structure on the surface and a porous scattering layer beneath it. The transmittance and reflectance curves of sunlight (0.3–2.4 μm) are shown in the attached figure. Figure 2 As shown in the attached figure, the mid-infrared emissivity curve is... Figure 3 As shown, the reflectivity is 0.95 and the emissivity is 0.943.

[0098] Example 10

[0099] 1) Using 2mm thick ultra-white soda-lime glass, the glass is first treated with nanosecond laser irradiation. The pulsed laser parameters are: center wavelength 532nm, pulse width 20 nanoseconds, minimum beam size 1mm, laser focus located about 10μm below the glass surface, and the glass is irradiated in a straight line at a scanning speed of 1m / s with a line spacing of about 1mm to obtain a porous pretreatment layer with a pulse dot distribution.

[0100] 2) A femtosecond laser is used to perform a second laser irradiation treatment on the surface grating structure. The pulsed laser parameters are: center wavelength 800nm, pulse width 120 femtoseconds, minimum beam size 8μm, and laser focus located about 7μm below the glass surface. The glass is irradiated line by line along a straight line at a scanning speed of 0.5m / s with a line spacing of about 0.01mm to obtain the surface grating structure pretreatment layer.

[0101] 3) The laser-pretreated glass was placed in an acid etching solution for chemical etching. The etching solution was HF 2wt%, and the etching was carried out at 50°C for 16 hours.

[0102] 4) Immerse the acid-etched glass in an alkaline etching solution (KOH solution, 5wt% KOH concentration) at 90°C for 24 hours. Remove, clean, and dry to obtain a daytime radiation-cooled glass with a grating structure on the surface and a porous scattering layer beneath the grating structure. The transmittance and reflectance curves of sunlight (0.3–2.4 μm) are shown in the attached figure. Figure 2 As shown in the attached figure, the mid-infrared emissivity curve is... Figure 3 As shown, the reflectivity is 0.97 and the emissivity is 0.95.

[0103] Example 11

[0104] 1) Use 2mm thick soda-lime glass, without laser treatment, and directly perform acid and alkali etching. The acid etching solution is HF concentration 0.2wt%, and the etching is carried out at 50℃ for 16 hours.

[0105] 2) Immerse the acid-etched glass in an alkaline etching solution (KOH solution, 0.5wt%) at 90°C for 20 hours, then remove, clean, and dry. The reflectivity to sunlight (0.3–2.4 μm) is 0.25, and the mid-infrared emissivity is 0.9.

[0106] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any form or substance. It should be noted that those skilled in the art can make various improvements and additions without departing from the method of the present invention, and these improvements and additions should also be considered within the scope of protection of the present invention. Any modifications, alterations, and equivalent changes made by those skilled in the art based on the above-disclosed technical content without departing from the spirit and scope of the present invention are equivalent embodiments of the present invention. Furthermore, any modifications, alterations, and evolutions made to the above embodiments based on the essential technology of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A daytime radiation cooling glass, characterized in that, A grating is provided on the glass surface, and a porous scattering layer is provided below the grating. The porous scattering layer includes micron-pores and nano-pores. The porous scattering layer adopts a discontinuous multilayer layout. The spacing of the grating is 1~10μm; The width of the grating is 1~10μm; The height of the grating is 1~10μm; The pore size of the micron-sized pore is 1~8μm; The pore size of the nanopore is 50~500nm; The method for preparing the daytime radiation-cooled glass includes irradiating the glass with a laser, and then sequentially performing acid etching and alkaline etching to obtain the daytime radiation-cooled glass. The laser irradiation includes a first laser irradiation and a second laser irradiation performed sequentially. The laser used for the first laser irradiation is selected from one or more of millisecond, microsecond, and nanosecond lasers; the power of the first laser irradiation is 10~1000W; the beam spot size of the first laser irradiation is 0.1~3mm; and a porous pretreatment layer with a dotted distribution is formed on the glass surface by the first laser irradiation. The laser used for the second laser irradiation is selected from one or more of nanosecond, picosecond, and femtosecond lasers; the power of the second laser irradiation is 50~1000W; the minimum beam size of the second laser irradiation is 3~20μm; and a grating structure pretreatment layer is formed on the glass surface by the second laser irradiation.

2. The daytime radiation cooling glass according to claim 1, characterized in that, The spectral modulation of the daytime radiation-cooled glass is selected from one or more of the 0.3~2.5μm sunlight and 8~13μm mid-infrared light bands.

3. The daytime radiation cooling glass according to claim 2, characterized in that, Includes at least one of the following technical features: B1) The daytime radiation cooling glass has a reflectivity of >90% for sunlight of 0.3~2.5μm. B2) The emissivity of the daytime radiation-cooled glass to the mid-infrared band of 8~13μm is >90%.

4. The daytime radiation cooling glass according to claim 3, characterized in that, Includes at least one of the following technical features: C1) The glass described is silicate glass; C2) The acid used for etching is selected from one or more of HF, HCl, H2SO4 and HNO3; The acid etching temperature described in C3) is 20~50℃; C4) The alkali used for alkaline etching is selected from one or more of KOH, NaOH, LiOH, and NH3·H2O; The alkaline etching temperature described in C5 is 40~95℃.

5. The daytime radiation cooling glass according to claim 4, characterized in that, Includes at least one of the following technical features: In feature C1), the silicate glass is selected from one of soda-lime glass, aluminosilicate glass, and borosilicate glass; C12) The linear spacing of the laser beams irradiated by the first laser is 1~5mm; C13) The center wavelength of the first laser irradiation is selected from one or more of 980nm, 1053nm and 1064nm; C14) The pulse width of the first laser irradiation is 20 nanoseconds to 5 milliseconds; C15) The laser focal point of the first laser irradiation is 5~15μm away from the glass surface; C16) The scanning speed of the first laser irradiation is 0.05~2m / s; C17) The line spacing of the first laser irradiation scan is 0.1~3mm; In characteristic C2), the mass concentration of the acid is 0.1~5.0 wt% (C18). In characteristic C4), the mass concentration of the alkali is 0.1~5.0 wt%.

6. The daytime radiation cooling glass according to claim 1, characterized in that, Includes at least one of the following technical features: D1) The center wavelength of the second laser irradiation is selected from one or more of 532nm, 660nm, 980nm and 1064nm; D2) The pulse width of the second laser irradiation is 100 femtoseconds to 5 nanoseconds; D3) The laser focal point of the second laser irradiation is 5~10μm away from the glass surface; D4) The scanning speed of the second laser irradiation is 0.1~1m / s; D5) The line spacing of the second laser irradiation scan is 0.01~0.02mm.

7. An application of daytime radiation cooling glass, characterized in that, The daytime radiative cooling glass according to any one of claims 1-6 is used for passive cooling of buildings and heat dissipation and cooling in the power and transportation fields.

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