Ga2O3 / PDMS radiation refrigeration photon film, preparation method and application
Through the Ga2O3/PDMS composite film structure, the problem of the inability to achieve both the refractive index and the band gap of the dielectric particle material is solved, and efficient radiative cooling performance and self-cleaning ability are achieved, which is suitable for building energy conservation, outdoor electronic cooling and wearable devices.
Patent Information
- Application Number
- CN202511014831.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-23
- Publication Date
- 2025-10-10
AI Technical Summary
The dielectric particle materials in existing photonic films have the problem of not having both refractive index and band gap, which leads to severe absorption of sunlight or poor scattering efficiency, affecting the radiative cooling performance.
A Ga2O3/PDMS composite film structure is adopted, and gallium oxide dielectric particles are uniformly dispersed in a polydimethylsiloxane matrix. The particle size is 0.5-1.5 μm, the refractive index is greater than 1.8, and the band gap is greater than 4.13 eV. The photonic film is prepared by doctor blade coating and degassing process.
It achieves a balance between high solar reflectivity and mid-infrared emissivity, improves the reflectivity and cooling performance of radiation cooling materials, has good mechanical flexibility and self-cleaning ability, and is suitable for building energy conservation, outdoor electronic cooling and wearable device temperature control.
Smart Images
Figure CN120758043A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of radiation refrigeration materials, and particularly relates to a Ga2O3 / PDMS radiation refrigeration photonic film, a preparation method and application thereof. BACKGROUND
[0002] As a new passive cooling technology, radiation refrigeration technology utilizes the infrared radiation ability of materials in the atmospheric transparent window 8-13 mu m to directly emit heat to outer space, thereby realizing natural cooling independent of any external energy. The key to realizing effective daytime radiation refrigeration lies in that the material simultaneously has high solar reflectivity and strong infrared emissivity. Existing radiation refrigeration materials include multilayer films, metal-dielectric structures, micro-nano porous films, and random particle structures, etc. Among them, the photonic film composed of dielectric particles and polymers has attracted widespread attention due to its simple structure, low cost, and easy preparation.
[0003] However, the dielectric particles such as TiO2 and ZnO used in the existing photonic film usually face the contradiction that the refractive index and the band gap cannot be compatible: high refractive index materials often have small band gaps, resulting in serious solar light absorption and reducing the reflectivity; and wide band gap materials such as SiO2 have good transparency, but due to the low refractive index, the scattering efficiency is poor, and the refrigeration performance is limited. SUMMARY
[0004] Therefore, some embodiments disclose a Ga2O3 / PDMS radiation refrigeration photonic film, which is a composite film structure of a polydimethylsiloxane matrix and gallium oxide dielectric particles; in the composite film structure, the gallium oxide dielectric particles are uniformly dispersed in the matrix, the particle size of the gallium oxide dielectric particles is between 0.5-1.5 mu m, and the mass fraction of the gallium oxide dielectric particles is 20%; the refractive index of the gallium oxide dielectric particles is greater than 1.8, and the band gap is greater than 4.13 eV; the average reflectivity of the photonic film in the wavelength range of 0.3-2.5 mu m of the solar spectrum is 94.5%, and the average emissivity in the infrared band of 8-13 mu m is 94.5%.
[0005] On the other hand, some embodiments disclose a preparation method of the Ga2O3 / PDMS radiation refrigeration photonic film, comprising the following steps:
[0006] S1, adding gallium oxide dielectric particles and a curing agent into a polydimethylsiloxane precursor solution to obtain a mixture; the particle size of the gallium oxide dielectric particles is between 0.5-1.5 mu m, the mass fraction of the gallium oxide dielectric particles is 20%, the refractive index of the gallium oxide dielectric particles is greater than 1.8, and the band gap is greater than 4.13 eV;
[0007] S2, uniformly stirring the mixture to obtain a composite slurry in which the gallium oxide particles are uniformly dispersed;
[0008] S3, applying the composite slurry evenly on the surface of the glass substrate by doctor blade coating to remove air from the composite slurry;
[0009] S4, degassing and then solidifying to obtain Ga2O3 / PDMS radiation cooling photonic film.
[0010] Furthermore, in the method for preparing the Ga2O3 / PDMS radiation cooling photonic film disclosed in some embodiments, in step S1, the mass ratio of the curing agent to the polydimethylsiloxane matrix is 1:10.
[0011] In the method for preparing the Ga2O3 / PDMS radiation cooling photonic film disclosed in some embodiments, in step S2, the stirring rate is 1000 rpm and the stirring time is 20 minutes.
[0012] In the preparation method of the Ga2O3 / PDMS radiation cooling photonic film disclosed in some embodiments, in step S3, degassing is performed under vacuum for 30 minutes.
[0013] In the method for preparing the Ga2O3 / PDMS radiation cooling photonic film disclosed in some embodiments, in step S4, the degassed film is naturally cured at room temperature for 24 hours, or thermally cured at 80°C for 2 hours.
[0014] On the other hand, some embodiments disclose applications of Ga2O3 / PDMS radiation cooling photonic films, where the Ga2O3 / PDMS radiation cooling photonic films are used as cooling materials.
[0015] Furthermore, in some embodiments, the application of Ga2O3 / PDMS radiation cooling photonic film disclosed in the embodiment shows that the net cooling power of Ga2O3 / PDMS radiation cooling photonic film reaches 115.9W / m2 at an ambient temperature of 27°C. 2 ; When the solar irradiance exceeds 700W / m 2 Under these conditions, the maximum temperature drop was 9.1℃.
[0016] The Ga2O3 / PDMS radiation cooling photonic film, preparation method, and application disclosed in the embodiments of the present invention have the following beneficial technical effects:
[0017] The Ga2O3 / PDMS composite structure effectively avoids the conflict between scattering intensity and visible light absorption in traditional granular photonic films while taking into account high solar reflectivity and mid-infrared emissivity, thereby improving the reflectivity and cooling performance of the photonic film as a daytime radiation cooling material.
[0018] A design principle for selecting particles based on material band gap and refractive index was proposed, providing a scalable technical route for building efficient dielectric scattering systems. Compared with commonly used materials such as TiO2 and ZnO, it has more comprehensive advantages in optical performance and environmental adaptability.
[0019] The photonic film formation process is simple, requires no solvents, and requires minimal equipment. It is suitable for the preparation of large-area flexible substrates and has the potential for industrial application. The resulting photonic film also has good mechanical flexibility, self-cleaning ability, and environmental stability, meeting the needs of long-term outdoor operation.
[0020] The photonic thin film material provided by the embodiment of the present invention has a wide range of applicability and can be applied to multiple scenarios such as building energy conservation, outdoor electronic cooling, and wearable device temperature control. It has strong practicality and promotion potential. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Figure 1 Flow chart of the preparation method of Ga2O3 / PDMS radiation cooling photonic film in Example 1;
[0022] Figure 2 Figure 1 shows the microstructure of the Ga2O3 / PDMS radiative cooling photonic film in Example 1; (a) scanning electron micrograph of a cross-section of the film, (b) surface morphology of the film, (c) element distribution of the film, (d) particle size distribution of Ga2O3 particles, and (e) infrared absorption spectra of the PDMS substrate and the Ga2O3 / PDMS photonic film.
[0023] Figure 3 The reflection spectrum and emission spectrum of the Ga2O3 / PDMS radiation cooling photonic film in Example 1 in the solar spectrum and infrared band;
[0024] Figure 4 The cooling performance test results of the Ga2O3 / PDMS photonic film in Example 1 under outdoor conditions are shown as follows: (a) daytime temperature change, (b) cooling amplitude, (c) solar irradiance, and (d) net cooling power under different heat transfer coefficients.
[0025] Figure 5 The comprehensive performance test results of the Ga2O3 / PDMS photonic film in Example 1; (a) thermogravimetric analysis curve, (b) comparison of spectral performance before and after 60 days of outdoor exposure, (c) contact angle measurement; (d) self-cleaning performance; (e) stress-strain curve, (f) display of mechanical properties such as stretching, twisting, and bending. DETAILED DESCRIPTION
[0026] The term "embodiment" is used herein specifically to describe any embodiment as "exemplary," and should not be construed as superior or preferable to other embodiments. Performance indicators in the embodiments of the present invention were tested using conventional testing methods in the art, unless otherwise specified. It should be understood that the terms used in the embodiments of the present invention are intended solely to describe specific implementations and are not intended to limit the disclosure of the embodiments of the present invention.
[0027] Unless otherwise specified, the technical and scientific terms used herein have the same meanings as commonly understood by those skilled in the art to which the embodiments of the present invention pertain; any experimental methods and technical means not otherwise specified in the embodiments of the present invention refer to experimental methods and technical means commonly used by those skilled in the art.
[0028] As used herein, the terms "substantially" and "approximately" are used to describe small fluctuations. For example, they can refer to less than or equal to ±5%, such as less than or equal to ±2%, such as less than or equal to ±1%, such as less than or equal to ±0.5%, such as less than or equal to ±0.2%, such as less than or equal to ±0.1%, such as less than or equal to ±0.05%. Numerical data expressed or presented in range format herein are used for convenience and brevity only and should therefore be interpreted flexibly to include not only the values explicitly listed as the limits of the range, but also all independent values or subranges contained within the range. For example, a numerical range of "1-5%" should be interpreted to include not only the explicitly listed values of 1% to 5%, but also the independent values and subranges within the indicated range. Thus, included in this numerical range are independent values such as 2%, 3.5%, and 4%, and subranges such as 1% to 3%, 2% to 4%, and 3% to 5%, etc. This principle also applies to ranges that only list a single value. Furthermore, this interpretation applies regardless of the width of the range or the characteristics described.
[0029] Throughout this document, including in the claims, transitional terms such as "comprises," "includes," "with," "having," "contains," "involving," and "accommodating" are understood to be open-ended, meaning "including but not limited to." Only the transitional terms "consisting of" and "composed of" are closed transitional terms.
[0030] In order to better illustrate the present invention, numerous specific details are provided in the following specific examples. It should be understood by those skilled in the art that the present invention can be practiced without certain specific details. In the examples, some methods, means, instruments, and equipment well known to those skilled in the art are not described in detail in order to highlight the main purpose of the present invention.
[0031] Under the premise of no conflict, the technical features disclosed in the embodiments of the present invention can be arbitrarily combined, and the resulting technical solutions belong to the contents disclosed in the embodiments of the present invention.
[0032] In some embodiments, the Ga2O3 / PDMS radiative cooling photonic film is a composite film structure of a polydimethylsiloxane matrix and gallium oxide dielectric particles; in the composite film structure, the gallium oxide dielectric particles are uniformly dispersed in the matrix, the particle size of the gallium oxide dielectric particles is between 0.5 and 1.5 μm, and the mass fraction of the gallium oxide dielectric particles is 20%; the refractive index of the gallium oxide dielectric particles is greater than 1.8, and the band gap is greater than 4.13 eV; the average reflectivity of the photonic film in the wavelength range of 0.3 to 2.5 μm in the solar spectrum reaches 94.5%, and the average emissivity in the infrared band of 8 to 13 μm reaches 94.5%.
[0033] On the other hand, some embodiments disclose a method for preparing a Ga2O3 / PDMS radiation cooling photonic film, comprising the steps of:
[0034] S1. Adding gallium oxide dielectric particles and a curing agent to a polydimethylsiloxane precursor solution to obtain a mixed material; the particle size of the gallium oxide dielectric particles is between 0.5 and 1.5 μm, and the mass fraction of the gallium oxide dielectric particles is 20%; the refractive index of the gallium oxide dielectric particles is greater than 1.8, and the band gap is greater than 4.13 eV;
[0035] S2. Stirring the mixture uniformly to obtain a composite slurry in which gallium oxide particles are uniformly dispersed;
[0036] S3, applying the composite slurry evenly on the surface of the glass substrate by doctor blade coating to remove air from the composite slurry;
[0037] S4, degassing and then solidifying to obtain Ga2O3 / PDMS radiation cooling photonic film.
[0038] Furthermore, in the method for preparing the Ga2O3 / PDMS radiation cooling photonic film disclosed in some embodiments, in step S1, the mass ratio of the curing agent to the polydimethylsiloxane matrix is 1:10.
[0039] In the method for preparing the Ga2O3 / PDMS radiation cooling photonic film disclosed in some embodiments, in step S2, the stirring rate is 1000 rpm and the stirring time is 20 minutes.
[0040] In the preparation method of the Ga2O3 / PDMS radiation cooling photonic film disclosed in some embodiments, in step S3, degassing is performed under vacuum for 30 minutes.
[0041] In the method for preparing the Ga2O3 / PDMS radiation cooling photonic film disclosed in some embodiments, in step S4, the degassed film is naturally cured at room temperature for 24 hours, or thermally cured at 80°C for 2 hours.
[0042] In another aspect, some embodiments disclose applications of Ga2O3 / PDMS radiative cooling photonic films, which are used as refrigeration materials. These refrigeration materials can be applied in a variety of scenarios, including building energy conservation, outdoor electronics cooling, and temperature control for wearable devices.
[0043] Furthermore, in some embodiments, the application of Ga2O3 / PDMS radiation cooling photonic film disclosed in the embodiment shows that the net cooling power of Ga2O3 / PDMS radiation cooling photonic film reaches 115.9W / m2 at an ambient temperature of 27°C. 2 ; When the solar irradiance exceeds 700W / m 2 Under these conditions, the maximum temperature drop was 9.1℃.
[0044] The technical details are further illustrated below with reference to embodiments.
[0045] Example 1
[0046] In Example 1, Figure 1 As shown, the preparation method of Ga2O3 / PDMS radiation cooling photonic film includes:
[0047] Ga2O3 particles are added to a PDMS precursor solution at a mass fraction of 20%, and a matching curing agent is added, wherein the mass ratio of the curing agent to the PDMS precursor is 1:10, to obtain a uniform mixture; wherein the PDMS precursor solution uses Component A of Dow Corning Sylgard 184, and the curing agent uses Component B of Dow Corning Sylgard 184, and the main component of the curing agent is a combination of a platinum-containing catalyst and a hydrogen-containing siloxane crosslinker;
[0048] The mixture was stirred at 1000 rpm for 20 minutes to ensure that the Ga2O3 particles were evenly dispersed to form a uniformly mixed composite slurry;
[0049] The composite slurry was evenly coated on the surface of the glass substrate by knife coating, and placed in a vacuum box for degassing at room temperature for 30 minutes to remove air from the mixture and ensure the uniformity of the film;
[0050] The degassed film was thermally cured at 80°C for 2 hours to obtain the Ga2O3 / PDMS radiation cooling photonic film.
[0051] Example 2
[0052] In Example 2, the Ga2O3 / PDMS radiation cooling photonic film obtained in Example 1 was characterized for its microstructure;
[0053] like Figure 2As shown, the Ga2O3 / PDMS radiative cooling photonic film obtained in Example 1 is composed of a PDMS matrix and uniformly dispersed Ga2O3 particles; wherein, the scanning electron microscope image (a) shows that the film thickness is about 550μm and the structure is dense; the surface image (b) shows that the Ga2O3 particles are evenly distributed without obvious agglomeration; the element energy spectrum analysis (c) shows that Si, C, O and Ga elements are evenly distributed in the PDMS film, and the Ga element is in the form of discrete points, indicating that the Ga2O3 particles are well dispersed; the particle size distribution diagram (d) shows that the average particle size of the Ga2O3 particles is 1.26μm, and the distribution is concentrated, which is conducive to stimulating Mie scattering and can improve the solar reflectivity; the infrared absorption spectrum (e) shows that PDMS has multiple vibration absorption peaks in the 8-13μm band, which can effectively improve the thermal radiation in the infrared band; the high reflection and high emission characteristics of the photonic film make it an ideal material for daytime radiative cooling.
[0054] Example 3
[0055] In Example 3, the spectral selectivity test of the Ga2O3 / PDMS radiative cooling photonic film obtained in Example 1 was performed;
[0056] like Figure 3 As shown, the Ga2O3 / PDMS radiative cooling photonic film obtained in Example 1 exhibits excellent spectrally selective radiative cooling performance; within the solar spectrum wavelength range of 0.3 to 2.5 μm, the average reflectivity of the photonic film reaches 94.5%, as shown by the red curve, which can effectively reflect solar radiation and reduce heat absorption; within the atmospheric transparent window of 8 to 13 μm, the average emissivity of the film is 94.5%, as shown by the blue curve, which can efficiently radiate its own heat to outer space; this combination of high reflectivity and high emissivity gives the film excellent thermal insulation and cooling capabilities during the day, providing an excellent solution for achieving efficient daytime radiative cooling.
[0057] Example 4
[0058] In Example 4, the cooling performance of the Ga2O3 / PDMS radiation cooling photonic film obtained in Example 1 was tested;
[0059] The Ga2O3 / PDMS radiative cooling photonic film obtained in Example 1 was tested outdoors under natural conditions. The cooling performance tests were conducted on the rooftop of Zhengzhou University, China (113°37′30″E, 34°44′49.924″N). During the tests, the photonic film was placed in a custom test setup measuring 20×10×15cm. 3The film is constructed of aluminum foil and thermally insulating foam to effectively isolate external thermal interference. The film surface temperature and ambient temperature are monitored in real time using pre-calibrated K-type thermocouples (TASiTA 612). Solar irradiance is measured by a solar power meter (RS-RA-AL) located near the device.
[0060] The test results are as follows Figure 4 As shown in Figure 2, (a) shows that the surface temperature of the Ga2O3 / PDMS photonic film is always lower than the ambient temperature during the period from 12:00 to 16:00, verifying that it has the ability to passively cool down under direct sunlight. (b) and (c) further show that when the solar irradiance exceeds 700W / m 2 Under the condition of 27℃, the photonic film can achieve a maximum daytime cooling of 9.1℃, with an average cooling range of 5.8℃; (d) is the net cooling power test result of the photonic film under different heat transfer coefficients. When the ambient temperature is 27℃, the net cooling power of the film can reach 115.9W / m 2 ; Even under conditions of higher heat transfer coefficients, stable cooling performance can be maintained, indicating that the photonic film can achieve continuous and stable cooling effects without the need for external energy input.
[0061] Example 5
[0062] In Example 5, the stability and adaptability of the Ga2O3 / PDMS radiation cooling photonic film obtained in Example 1 were tested;
[0063] The test results are as follows Figure 5 As shown, Ga2O3 / PDMS photonic film exhibits good stability and adaptability in a variety of performance tests;
[0064] Figure 5In the figure, the thermogravimetric analysis results in (a) show that the mass loss of the photonic film is less than 2% in the temperature range of 25 to 200 ° C, which confirms its structural stability and ability to remain intact in common temperature fluctuations without decomposition or structural damage; (b) shows the optical properties of the photonic film material after 60 days of outdoor exposure, where the changes in solar reflectivity and infrared emissivity are less than 1%, indicating that even after long-term exposure to environmental factors such as sunlight, moisture, and temperature changes, the photonic film can still maintain stable spectral characteristics, showing excellent durability; the static contact angle measurement in (c) shows that the maximum value reaches 121.36°, proving that the surface of the photonic film is hydrophobic, which helps the droplets roll off; (d The dynamic images in (e) record the phenomenon that water droplets slide down quickly after contacting the photonic film, which shows that no liquid droplets will be retained on the surface of the photonic film, and the adhesion of pollution can be reduced under conditions of rain erosion or air dust. It has a certain self-cleaning ability, which is beneficial to extend the service life and reduce maintenance requirements; the mechanical test results in (e) confirm that the photonic film can withstand a strain of more than 200% without structural failure, showing its high ductility and elasticity; (f) records that the photonic film can return to its original state after stretching, twisting and bending, without obvious permanent deformation, and the structural integrity is maintained, which makes the photonic film suitable for use in dynamic environments; these characteristics together ensure the reliable operation of the film in various extreme and complex environments.
[0065] The technical solutions and technical details disclosed in the embodiments of the present invention are merely illustrative of the inventive concept of the present invention and do not constitute a limitation on the technical solutions of the embodiments of the present invention. Any conventional changes, replacements or combinations of the technical details disclosed in the embodiments of the present invention have the same inventive concept as the present invention and are within the scope of protection of the claims of the present invention.
Claims
1. Ga2O3 / PDMS radiation cooling photonic film, characterized by: The photonic film is a composite film structure of a polydimethylsiloxane matrix and gallium oxide dielectric particles. In the composite film structure, the gallium oxide dielectric particles are uniformly dispersed in the matrix, the particle size of the gallium oxide dielectric particles is between 0.5 and 1.5 μm, and the mass fraction of the gallium oxide dielectric particles is 20%. The refractive index of the gallium oxide dielectric particles is greater than 1.8, and the band gap is greater than 4.13 eV. The average reflectivity of the photonic film in the wavelength range of 0.3 to 2.5 μm in the solar spectrum is 94.5%, and the average emissivity in the infrared band of 8 to 13 μm is 94.5%.
2. The method for preparing the Ga2O3 / PDMS radiation cooling photonic film according to claim 1, characterized in that: Including steps: S1. Adding gallium oxide dielectric particles and a curing agent to a polydimethylsiloxane precursor solution to obtain a mixed material; the particle size of the gallium oxide dielectric particles is between 0.5 and 1.5 μm, the mass fraction of the gallium oxide dielectric particles is 20%, and the refractive index of the gallium oxide dielectric particles is greater than 1.8 and the band gap is greater than 4.13 eV; S2. Stirring the mixture uniformly to obtain a composite slurry in which gallium oxide particles are uniformly dispersed; S3, applying the composite slurry evenly on the surface of the glass substrate by doctor blade coating to remove air from the composite slurry; S4, degassing and then solidifying to obtain Ga2O3 / PDMS radiation cooling photonic film.
3. The method for preparing the Ga2O3 / PDMS radiation cooling photonic film according to claim 2, characterized in that: In step S1, the mass ratio of the curing agent to the polydimethylsiloxane matrix is 1:
10.
4. The method for preparing the Ga2O3 / PDMS radiation cooling photonic film according to claim 2, characterized in that: In step S2, the stirring rate is 1000 rpm and the stirring time is 20 min.
5. The method for preparing the Ga2O3 / PDMS radiation cooling photonic film according to claim 2, characterized in that: In step S3, degassing is performed under vacuum, and the degassing time is 30 minutes.
6. The method for preparing the Ga2O3 / PDMS radiation cooling photonic film according to claim 2, characterized in that: In step S4, the degassed film is naturally cured at room temperature for 24 hours, or thermally cured at 80° C. for 2 hours.
7. The use of the Ga2O3 / PDMS radiation cooling photonic film according to claim 1, characterized in that: The Ga2O3 / PDMS radiation refrigeration photonic film is used as a refrigeration material.
8. The use of the Ga2O3 / PDMS radiation cooling photonic film according to claim 7, characterized in that: At an ambient temperature of 27°C, the net cooling power of the Ga2O3 / PDMS radiation cooling photonic film reaches 115.9W / m 2 ; When the solar irradiance exceeds 700W / m 2 Under these conditions, the maximum temperature drop was 9.1℃.