VO2 / ZnSe composite film, and preparation method and application thereof

Abstract

The present application relates to the technical field of thermochromic film, in particular to a VO2 / ZnSe composite film, a preparation method and application thereof.The VO2 / ZnSe composite film comprises a thermochromic functional film layer (2) and a color regulation layer (3); the thermochromic functional film layer (2) is combined with a substrate (1).The present application provides a VO2 / ZnSe composite film, by continuously depositing a ZnSe film on the VO2 thermochromic functional film layer, the specific absorption characteristics of the ZnSe film in the visible light segment are used to change the brownish yellow color of the VO2-based thermochromic film, so that the composite film achieves a balance between optical performance and color in line with architectural aesthetics.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of thermochromic thin films, in particular to a VO2 / ZnSe composite thin film and a preparation method and application thereof. BACKGROUND

[0002] Statistics show that building energy consumption accounts for about 40% of the total global energy consumption, and this value is expected to further increase with the continuous growth of the population, so an efficient energy management system is the core method to prevent large-scale power outages due to severe energy shortages. Windows, as a medium for heat exchange between buildings and the outside world, account for the largest proportion of building energy consumption, so improving the energy-saving effect of windows is the key to reducing building energy loss. Therefore, the intelligent window with environmental perception and dynamic adjustment of solar radiation has become a research hotspot. For example, vanadium dioxide (VO2) is a thermotropic phase change material that changes from an insulator state to a metal state at a phase change temperature of 68℃. When the temperature is lower than 68℃, VO2 exhibits a monoclinic structure and exhibits insulating properties. The infrared transmittance of the VO2 thin film is very high. When the temperature is higher than 68℃, it exhibits a rutile structure and exhibits a metal state. The infrared transmittance of the VO2 thin film is greatly reduced. Therefore, the thermochromic intelligent window based on VO2 can prevent the interior of the building from overheating by reflecting most of the incident light in summer, and can transmit sunlight and absorb solar heat to keep the room warm in winter, which can improve the efficiency of energy utilization. However, in practical applications, the unattractive brownish yellow color, high phase change temperature (T c ) and the difficulty in balancing the visible light transmittance (T lum ) and the solar energy regulation efficiency (ΔT sol ) of the intrinsic VO2 thin film seriously restrict the commercial application of the VO2 thin film intelligent window.

[0003] In order to improve the performance of the VO2 thin film intelligent window, there are generally three methods. One is doping, which changes the transmittance and solar energy regulation efficiency of the VO2 thin film by doping other metal ions; the second is to deposit an antireflection layer on the surface of the VO2 thin film to reduce the reflection of visible light and improve the transmittance; and the third is to design and prepare a subwavelength micro-nano structure (such as a moth eye structure) based on the equivalent medium theory, which can also improve the visible light transmittance and solar energy regulation efficiency of the VO2 thin film by increasing the surface roughness and reducing the surface equivalent refractive index. The above methods can improve the thermochromic performance of the VO2 thin film to some extent, but cannot control the color of the VO2 thin film. Therefore, designing and preparing a new type of VO2 composite thin film is the key to solving the contradiction between the performance of the intelligent window and the aesthetics of the building. SUMMARY

[0004] The application aims to provide a VO2 / ZnSe composite film and a preparation method and application thereof.

[0005] To achieve the above-mentioned object, the application provides the following solutions.

[0006] In one of the technical solutions of the application, the VO2 / ZnSe composite film comprises a thermochromic functional film layer and a color control layer.

[0007] The thermochromic functional film layer (2) is a VO2 film, and the color control layer (3) is a ZnSe film.

[0008] The thermochromic functional film layer is combined with a substrate.

[0009] In some embodiments of the application, the thickness of the thermochromic functional film layer is 50-150 nm.

[0010] In some embodiments of the application, the thickness of the color control layer is 200-400 nm.

[0011] In another technical solution of the application, a preparation method of the above-mentioned VO2 / ZnSe composite film comprises the following steps.

[0012] The thermochromic functional film layer is deposited on a substrate by using a pulse laser deposition method, and then the color control layer is deposited on the thermochromic functional film layer to obtain the VO2 / ZnSe composite film.

[0013] In some embodiments of the application, when the thermochromic functional film layer is deposited on the substrate, the target material for deposition is a V target, the oxygen pressure is 0.2-1.2 Pa, the oxygen flow rate is 10-90 sccm, the substrate temperature is 150-500 DEG C, the laser frequency is 1-12 Hz, the growth rate of the thermochromic functional film layer is 0.5-2 nm / min, and the deposition time is 20-80 min.

[0014] In some embodiments of the application, when the color control layer is deposited on the thermochromic functional film layer, the target material for deposition is a ZnSe target, the deposition is carried out in a vacuum environment, the substrate temperature is 50-550 DEG C, the laser frequency is 2-12 Hz, the growth rate of the color control layer is 5-20 nm / min, and the deposition time is 5-30 min.

[0015] In some embodiments of the application, the substrate is a quartz glass substrate.

[0016] The method further comprises the steps of sequentially placing the substrate in acetone, anhydrous ethanol and deionized water for ultrasonic cleaning for 20 minutes.

[0017] The third aspect of the present application is the application of the VO2 / ZnSe composite film in the thermochromic smart window.

[0018] The fourth aspect of the present application is a thermochromic smart window comprising the VO2 / ZnSe composite film and quartz glass.

[0019] The present application has the following technical effects:

[0020] The present application provides a VO2 / ZnSe composite film, which is prepared by depositing a ZnSe film on a VO2 thermochromic functional film layer, and the brownish yellow color of the VO2-based thermochromic film is changed by using the specific absorption characteristics of the ZnSe film in the visible light range, so that the composite film achieves a balance between optical performance and color that meets the architectural aesthetics.

[0021] The VO2 / ZnSe composite film has a double-layer composite structure, which changes the brownish yellow color of the VO2-based thermochromic film to green that meets the architectural aesthetics, and improves the thermochromic performance of the VO2-based thermochromic film.

[0022] The VO2 / ZnSe composite film can be prepared by a pulsed laser deposition system, and the preparation process does not depend on high-cost and high-precision process conditions and equipment such as templates and photolithography, and the preparation process is more simple and stable. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0024] Figure 1 The figure is a structural diagram of the VO2 / ZnSe composite film of the present application, wherein 1 is a glass substrate layer, 2 is a thermochromic functional film layer (VO2), and 3 is a color adjusting layer.

[0025] Figure 2 The figure is a transmittance spectrum of the VO2 film prepared in the comparative example in the visible-near infrared wide spectrum domain, and the inserted figure is a photograph of the comparative example.

[0026] Figure 3 The figure is a transmittance spectrum of the VO2 / ZnSe composite film prepared in Example 1 in the visible-near infrared wide spectrum domain, and the inserted figure is a photograph of Example 1.

[0027] Figure 4 The transmittance spectrum of the VO2 / ZnSe composite film prepared in Example 2 in the visible-near infrared wide spectrum domain, the inset is the actual photo of Example 2. DETAILED DESCRIPTION

[0028] Various exemplary embodiments of the present application will now be described in detail, which should be considered to be illustrative of certain aspects, features and embodiments of the present application, but not a limitation of the present application.

[0029] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application. Additionally, for a range of values of a parameter, unless otherwise stated, each intervening value of the parameter is also specifically included within the scope of the present application. The intervening values of the parameter are combined with a stated value of the parameter in range form. These are only exemplary of the various preferred embodiments and are not intended to be limiting on the scope of the application. Other embodiments of the present application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. Various embodiments of the present application will be described in detail, by reference to drawings, wherein:

[0030] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present application, the preferred methods and materials are described. All patents, patent applications, publications, and descriptions mentioned herein are incorporated by reference in their entirety for the disclosure and

[0031] Many modifications and variations of this application can be made in the light of the above teachings without departing from the spirit and scope thereof, and it is to be understood that all such modifications and variations warrant the patentable subject matter under the patent statutes. Other embodiments of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. Additional embodiments of the present application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the application being indicated by the following claims.

[0032] As used herein, the terms "comprise", "comprising", "include", "including", "have", "having" and the like are open-ended and do not exclude additional, unrecited elements or method steps.

[0033] The meanings of the abbreviations used in the present application are as follows:

[0034] ΔT sol : solar regulation efficiency

[0035] T c : phase transition temperature

[0036] T lum : visible light transmittance

[0037] The first aspect of the present application provides a VO2 / ZnSe composite film, comprising a thermochromic functional film layer and a color control layer.

[0038] The thermochromic functional film layer (2) is a VO2 film; and the color control layer (3) is a ZnSe film.

[0039] The thermochromic functional film layer is combined with the substrate.

[0040] In some embodiments of the present application, the thickness of the thermochromic functional film layer is 50-150 nm.

[0041] In some embodiments of the present application, the thickness of the color control layer is 200-400 nm.

[0042] The ZnSe film exhibits a high absorption rate in the wavelength range of about 550-650 nm, indicating that it has a strong absorption capacity for red light, resulting in a relatively increased green component in the transmitted light, so that the transmitted light appears greenish. The ZnSe film with a thickness of about 300 nm not only exhibits a high transmittance in the near-infrared segment, but also has specific absorption characteristics in the visible light segment, and has excellent optical properties. Due to its optical properties and good crystallinity, the ZnSe film can be used as a material for improving the color of VO2. The present application utilizes the specific absorption characteristics of the ZnSe film in the visible light segment to change the brownish yellow color of the VO2-based thermochromic film, so that the VO2 intelligent window film balances between excellent optical performance and color that meets the architectural aesthetics, and provides new ideas and theoretical guidance for the microstructure design of new high-performance VO2-based intelligent window.

[0043] In the present application, the color control layer is used to generate an absorption peak in the visible light range to control the color of the film; and the thermochromic functional film layer is used to adjust the thermochromic performance.

[0044] In the present application, too thin or too thick thickness of the thermochromic functional film layer will result in poor thermochromic performance of the sample, so the present application preferably limits the thickness of the thermochromic functional film layer to the above parameter range.

[0045] In the present application, too thin or too thick thickness of the color control layer will result in no absorption peak in the visible light range, and the color cannot be effectively controlled, so the present application preferably limits the thickness of the color control layer to the above parameter range.

[0046] The second aspect of the present application provides a preparation method of the above-mentioned VO2 / ZnSe composite film, comprising the following steps:

[0047] The quartz glass substrate is sequentially placed in acetone, anhydrous ethanol and deionized water for ultrasonic cleaning for 20 min, so as to remove impurities, oil stains, particles and other organic or inorganic contaminants on the surface of the substrate.

[0048] The heat-induced color change functional film layer is deposited on a quartz glass substrate by using a pulse laser deposition system, the target material for deposition is a V target, the oxygen pressure is 0.2-1.2 Pa, the oxygen flow rate is 10-90 sccm, the substrate temperature is 150-500 DEG C, the laser frequency is 1-12 Hz, the growth rate of the heat-induced color change functional film layer 2 is 0.5-2 nm / min, and the deposition time is 20-80 min; the color control layer is deposited on the heat-induced color change functional film layer, the target material for deposition is a ZnSe target, in a vacuum atmosphere, the substrate temperature is 50-550 DEG C, the laser frequency is 2-12 Hz, the growth rate of the color control layer is 5-20 nm / min, and the deposition time is 5-30 min.

[0049] In the present application, the parameters for depositing the heat-induced color change functional film layer exceeding the above-mentioned parameter range will result in a decrease in film quality, and it is possible to produce impurities such as V2O3 and V2O5 due to insufficient or excessive oxygen; the parameters for depositing the color control layer exceeding the above-mentioned parameter range will result in uneven film formation and poor quality of the color control layer, respectively.

[0050] The third aspect of the present application provides the application of the above-mentioned VO2 / ZnSe composite film in a heat-induced color change intelligent window.

[0051] The fourth aspect of the present application provides a heat-induced color change intelligent window comprising the above-mentioned VO2 / ZnSe composite film and a quartz glass.

[0052] As an improvement of the technical solution of the present application, other functional films can be further introduced above or below the structure of the VO2 / ZnSe composite film of the present application, so that the composite film has better performance or function.

[0053] The detection method involved in the embodiments and the control examples of the present application: the light transmission spectrum of the VO2 / ZnSe composite film or the VO2 film is measured by using a UV-3600 (Shimazu) ultraviolet-visible-infrared spectrophotometer, and all tests are carried out in an atmospheric environment.

[0054] The raw materials used in the embodiments of the present application can be obtained through commercial channels, unless otherwise specified.

[0055] The quartz glass substrate used in the embodiments of the present application needs to be pretreated before being put into the chamber of the pulse laser deposition system, the quartz glass is sequentially ultrasonically cleaned in acetone, anhydrous ethanol and deionized water for 20 min, and then dried with nitrogen to remove surface impurities, oil stains, particles and other organic or inorganic pollutants.

[0056] The present application is further described below through examples.

[0057] Example 1

[0058] As shown in the figure, the VO2 / ZnSe composite film is composed of a thermochromic functional film layer 2 and a color control layer 3; the thermochromic functional film layer 2 is deposited on the transparent quartz glass substrate layer 1, and the color control layer 3 is formed on the thermochromic functional film layer 2. Figure 1

[0059] The preparation method of the VO2 / ZnSe composite film is as follows:

[0060] The transparent quartz glass substrate is placed in the chamber of the pulsed laser deposition system, the thermochromic functional film layer 2 is deposited on the transparent quartz glass substrate layer 1, the target material for deposition is a V target, the oxygen pressure is 0.9 Pa, the oxygen flow rate is 30 sccm, the substrate temperature is 480°C, the laser frequency is 2 Hz, the growth rate of the thermochromic functional film layer 2 is 1.2 nm / min, and the deposition time is 60 min; the color control layer 3 is deposited on the thermochromic functional film layer, the target material for deposition is a ZnSe target, the substrate temperature is 200°C in a vacuum environment, the laser frequency is 5 Hz, the growth rate of the color control layer 3 is 15 nm / min, and the deposition time is 20 min; and the VO2 / ZnSe composite film is obtained.

[0061] Figure 3 The transmittance spectrum of the VO2 / ZnSe composite film prepared in this example in the visible-near infrared wide spectral domain is shown in the figure, and the inset is a photograph of the actual product of Example 1. Figure 3 As can be seen, the VO2 / ZnSe composite film is green, and the solar energy regulation efficiency in the wavelength range of 280-2650 nm is 10.94%.

[0062] Example 2

[0063] The difference between this example and Example 1 is only that the deposition time of the thermochromic functional film layer 2 on the transparent quartz glass substrate layer 1 is 70 min, and the remaining steps and parameters are the same as those of Example 1; and the VO2 / ZnSe composite film is obtained. (That is, the deposition time of the thermochromic functional film layer 2 in Example 1 is adjusted from 60 min to 70 min)

[0064] Figure 4 The transmittance spectrum of the VO2 / ZnSe composite film prepared in this example in the visible-near infrared wide spectral domain is shown in the figure, and the inset is a photograph of the actual product of Example 2. Figure 4 As can be seen, the VO2 / ZnSe composite film is green, and the solar energy regulation efficiency in the wavelength range of 280-2650 nm is 12.5%.

[0065] Comparative Example

[0066] ​The difference between the example 1 and the present comparative example is that the deposition of the color regulating layer 3 is omitted, and the rest of the steps and parameters are the same as those of the example 1; a VO2 thin film is obtained. (i.e. the thermochromic functional thin film layer 2 is directly deposited on the transparent quartz glass substrate layer 1, and the preparation conditions are the same as those of the example 1, and there is no second color regulating layer 3)

[0067] Figure 2 The transmittance spectrum of the VO2 thin film prepared for the present comparative example in the visible-near infrared wide spectral domain is shown in the drawing, and the photograph of the comparative example is shown in the drawing, which is prepared by Figure 2 It can be seen that the single-layer VO2 thin film is brown, and the solar energy regulation efficiency in the wavelength range of 280-2650 nm is 7.1%.

[0068] The above-described examples only describe the preferred modes of the present application, and do not limit the scope of the present application. Various modifications and improvements to the technical solutions of the present application made by those skilled in the art without departing from the design spirit of the present application shall fall within the protection scope of the present application defined by the claims.

Claims

1. A V02 / ZnSe composite thin film, characterized in that, The VO2 / ZnSe composite thin film comprises a thermochromic functional thin film layer (2) and a color control layer (3). The thermochromic functional thin film layer (2) is a VO2 thin film, and the color control layer (3) is a ZnSe thin film. The thermochromic functional thin film layer (2) is combined with the substrate (1). The thickness of the thermochromic functional thin film layer (2) is 50-150 nm. The thickness of the color control layer (3) is 200-400 nm.

2. A method for preparing the VO2 / ZnSe composite film according to claim 1, characterized in that, The VO2 / ZnSe composite thin film comprises the following steps: The thermochromic functional thin film layer (2) is deposited on the substrate (1), and then the color control layer (3) is deposited on the thermochromic functional thin film layer (2) to obtain the VO2 / ZnSe composite thin film.

3. The method for preparing the VO2 / ZnSe composite thin film according to claim 2, characterized in that, When the thermochromic functional thin film layer (2) is deposited on the substrate (1), the target material for deposition is a V target, the oxygen pressure is 0.2-1.2 Pa, the oxygen flow rate is 10-90 sccm, the substrate (1) temperature is 150-500℃, the laser frequency is 1-12 Hz, the growth rate of the thermochromic functional thin film layer (2) is 0.5-2 nm / min, and the deposition time is 20-80 min.

4. The method for preparing the VO2 / ZnSe composite thin film according to claim 2, characterized in that, When the color control layer (3) is deposited on the thermochromic functional thin film layer (2), the target material for deposition is a ZnSe target, the deposition is carried out in a vacuum environment, the substrate (1) temperature is 50-550℃, the laser frequency is 2-12 Hz, the growth rate of the color control layer (3) is 5-20 nm / min, and the deposition time is 5-30 min.

5. The method for preparing the VO2 / ZnSe composite thin film according to claim 2, characterized in that, The substrate (1) is a quartz glass substrate.

6. The application of the VO2 / ZnSe composite thin film in a thermochromic intelligent window according to claim 1.

7. A thermochromic smart window, characterized in that, The VO2 / ZnSe composite thin film and the quartz glass according to claim 1.

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