WO2024007275A1

WO2024007275A1 - Smart window foil self-adaptive to illumination intensity, and preparation method therefor and use thereof

Info

Publication number: WO2024007275A1
Application number: PCT/CN2022/104508
Authority: WO
Inventors: 王京霞; 孟维豪; 高颖韬; 江雷
Original assignee: 北京仿生界面科学未来技术研究院
Priority date: 2022-07-05
Filing date: 2022-07-08
Publication date: 2024-01-11
Also published as: CN115353701B; CN115353701A

Abstract

A smart window foil self-adaptive to illumination intensity, and a preparation method therefor and the use thereof. The smart window foil comprises a carrier and photochromic inorganic nanoparticles, and may also comprise a catalyst, wherein the photochromic inorganic nanoparticles are converted from an oxidation state to a reduction state after absorbing sunlight, such that the color of the smart window foil changes from light to dark during self-adaption to the sunlight intensity; when the photochromic inorganic nanoparticles cannot absorb sunlight, the photochromic inorganic nanoparticles are converted into an oxidation state from a reduction state, such that the color of the smart window foil changes from dark to light until reaching a colorless state during self-adaption to sunlight intensity; and the catalyst affects the sensitive degree of the self-adaptivity of the smart window foil to illumination. The smart window foil is prepared by means of a coating method, is suitable for large-area production, is transparent in a colorless oxidation state and a colored reduction state, can be attached to existing window glass without replacing existing windows, is convenient to use, has the advantages of flexibility, a self-supporting property, low cost, no scattering, better energy conservation and environmental protection properties, etc., and has wide application prospects.

Description

A smart window foil that can adapt to light intensity and its preparation method and application

Technical field

The invention relates to the technical field of layered products, and in particular to an intelligent window foil that can adapt to light intensity and its preparation method and application.

Background technique

As environmental protection and energy conservation receive increasing attention, calls for rational utilization of energy are getting louder and louder. At the same time, great progress has been made in the research and development of energy-saving products. Against this background, in the early 1980s, C.M. Lampert, C.G. Granqvist and others first proposed the application of electrochromic materials in energy-saving lighting systems for buildings, automobiles, aircraft, etc., to form a "system that can dynamically adjust the transmittance of solar radiation." "Smartwindow". In recent years, the research and application of smart windows has been a hot research topic.

At present, electrochromic smart windows based on tungsten trioxide or polymer-dispersed liquid crystal are widely used. However, their device structures are complex, their production costs are high, they require complex circuit devices, require additional energy consumption, and will cause certain safety issues. Hidden danger.

Therefore, passive thermochromic or photochromic smart windows that regulate their transmittance based on changes in environmental temperature or light intensity have received widespread attention. Photochromic smart windows are currently mainly based on organic photochromic dyes, which suffer from poor stability and poor fatigue resistance. Photochromic inorganic nanoparticles show good stability and fatigue resistance. The most representative of inorganic photochromic materials is tungsten trioxide. However, the preparation method of inorganic photochromic smart windows requires a high-temperature sintering process, which limits its use on rigid substrates, or requires expensive high-vacuum magnetron sputtering equipment on flexible substrates, increasing manufacturing costs or limiting the use of smart windows. The existing ordinary windows need to be replaced, which is complex and costly, which seriously hinders the development of smart window materials. In addition, the slow switching speed of photochromic smart windows between different transmittances is also a problem that needs to be solved urgently.

Therefore, it is very important to develop a smart window foil based on inorganic photochromic nanoparticles that can adapt to light intensity to overcome the above problems.

Contents of the invention

In order to solve the cost and efficiency problems of photochromism, the present invention provides an intelligent window foil that can adapt to light intensity and its preparation method and application. When using the intelligent window foil, there is no need to replace the original window and it is directly attached It can be used on the surface of ordinary windows, is easier to operate, has no external energy consumption, and is flexible, self-supporting, low cost, and non-scattering. The preparation method is simple and eliminates the need for high-temperature sintering or the like in traditional preparation processes. High-vacuum magnetron sputtering and other methods have broadened the scope of use and reduced manufacturing costs; the application of smart window foils that can adapt to light intensity is used to adjust the solar transmittance.

The invention provides an intelligent window foil that can adapt to light intensity, including a carrier and photochromic inorganic nanoparticles;

The carrier is used to uniformly distribute the photochromic inorganic nanoparticles;

Photochromic inorganic nanoparticles have an oxidation state and a reduction state. The oxidation state is a colorless state and the reduction state is a colored state. Photochromic inorganic nanoparticles are used to convert from the oxidation state to the reduction state after absorbing sunlight to make smart window foils The color of the smart window foil adapts to the sunlight intensity from light to dark. The photochromic inorganic nanoparticles are used to convert from the reduced state to the oxidation state when the sunlight cannot be absorbed, so that the color of the smart window foil adapts to the sunlight intensity from dark to light. Reach colorless state.

The present invention is a smart window foil that can adapt to light intensity. As a preferred mode, the components of the smart window foil also include a catalyst. The catalyst is used to regulate the conversion of photochromic inorganic nanoparticles from a reduced state to an oxidized state. rate.

In the smart window foil that can adapt to light intensity according to the present invention, as a preferred mode, the photochromic inorganic nanoparticles are wide bandgap semiconductor materials;

Photochromic inorganic nanoparticles are any of the following: titanium dioxide, tungsten trioxide and molybdenum trioxide;

The material of the carrier is polymer, which is colorless and transparent;

Smart window foil is a transparent sheet structure.

In the smart window foil that can adapt to light intensity according to the present invention, as a preferred method, the particle size of the photochromic inorganic nanoparticles is 2 to 10 nm, and the weight ratio of the photochromic inorganic nanoparticles to the polymer is 5 to 5 nm. 10%, the light absorption band of photochromic inorganic nanoparticles is 250~400nm;

The carrier is any of the following: polymethyl methacrylate, polycarbonate and polystyrene;

The thickness of smart window foil is 20~60μm.

In a smart window foil that can adapt to light intensity according to the present invention, as a preferred mode, the catalyst is any one of the following: platinum, copper chloride and chromium chloride, and the weight ratio of the catalyst to the photochromic inorganic nanoparticles is 0～10%.

The invention provides a method for preparing intelligent window foil that can adapt to light intensity, including the following steps:

S1. Preparing the sol: Dissolve the precursor of the photochromic inorganic nanoparticles in the first solvent and stir to obtain the sol;

S2. Preparation of solid sol: Add the sol to the second solvent containing the polymer. The solubility of the photochromic inorganic nanoparticles in the first solvent is greater than the solubility in the polymer. The photochromic effect is achieved by supersaturating the solution. Inorganic nanoparticles are dispersed in polymers to obtain solid sol;

S3. Preparation of smart window foil: Use a coating method to evenly apply the solid solution on the glass substrate, dry and demould to obtain a smart window foil that can adapt to light intensity.

In the preparation method of a smart window foil that can adapt to light intensity according to the present invention, as a preferred way, in step S1, the first solvent is N,N-dimethylformamide, and the photochromic inorganic nanoparticles are in the sol The concentration in the product is 0.1~0.3g/mL, and the stirring time is 1~3h;

In step S2, the second solvent is dichloroethane, and the concentration of the polymer in the second solvent is: 0.2~0.6g/mL;

In step S3, the drying temperature is 40-70°C, and the drying time is 1-4 hours.

The preparation method of a smart window foil that can adapt to light intensity according to the present invention, as a preferred method, includes the following steps:

S1. Preparing the sol: Dissolve the precursor and catalyst of the photochromic inorganic nanoparticles in the first solvent, and obtain the sol after stirring;

S3. Preparation of smart window foil: Use the coating method to evenly apply the solid solution on the glass substrate. After drying and demoulding, a smart window foil that can adapt to light intensity is obtained.

In the preparation method of a smart window foil that can adapt to light intensity according to the present invention, as a preferred method, the first solvent is N,N-dimethylformamide, and the concentration of photochromic inorganic nanoparticles in the sol is 0.1～0.3g/mL, the concentration of the catalyst in the sol is 0.02～0.03g/mL, and the stirring time is 1～3h;

The present invention is an application of an intelligent window foil that can adapt to light intensity. The intelligent window foil is used to adjust the transmittance of sunlight.

The present invention is an intelligent window foil that can adapt to light intensity, including polymers, photochromic inorganic nanoparticles and catalysts;

Polymers include but are not limited to colorless and transparent polymethylmethacrylate, polycarbonate, polystyrene, etc.;

Preferably, the polymer is polymethylmethacrylate;

Photochromic inorganic nanoparticles include but are not limited to titanium dioxide, tungsten trioxide, molybdenum trioxide, etc.;

Preferably, the photochromic inorganic nanoparticles are tungsten trioxide;

Catalysts include but are not limited to platinum, copper chloride, chromium chloride, etc.;

Preferably, the catalyst is copper chloride;

Preferably, the weight ratio of tungsten trioxide to polymethyl methacrylate is 5wt% to 10wt%;

Preferably, the weight ratio of copper chloride to tungsten trioxide is 0wt% to 10wt%;

The absorption band of tungsten trioxide is 250~400nm;

The thickness of smart window foil that can adapt to light intensity is 20μm~60μm.

The invention provides a method for preparing a smart window foil that can adapt to light intensity, which includes the following steps: dissolving the precursor of photochromic inorganic nanoparticles in N,N-dimethylformamide, stirring to form a sol, and then The sol is added to a solution containing a transparent polymer, stirred, and coated with a smart window foil that can adapt to light intensity;

The precursor of the photochromic inorganic nanoparticles is chloride; preferably, the concentration of tungsten chloride in the sol is 0.1 to 0.3g/mL; preferably, the polymethyl methacrylate in the solution containing polymethyl methacrylate The concentration is 0.2~0.6g/mL;

The stirring time is 1 to 3 hours, the drying temperature is 40 to 70°C, and the drying time is 1 to 2 hours.

The invention provides an application of an intelligent window foil that can adapt to light intensity in adjusting the solar transmittance.

The first object of the present invention is to provide an intelligent window foil that can adapt to light intensity. When using this smart window foil, there is no need to replace the original window. It can be directly attached to the surface of ordinary windows for use. It is easier to operate, has no external energy consumption, and is flexible, self-supporting, low cost, and has no scattering.

The second object of the present invention is to provide a method for preparing the above smart window foil that can adapt to light intensity. The preparation method has a simple process and eliminates the need for high-temperature sintering or high-vacuum magnetron sputtering in traditional preparation processes, broadens the scope of use, and reduces manufacturing costs.

The third object of the present invention is to provide an application in adjusting the solar transmittance using the above intelligent window foil that can adapt to the light intensity.

In order to achieve the above-mentioned first purpose, the present invention adopts the following technical solutions:

The invention discloses an intelligent window foil that can adapt to light intensity, including a polymer, inorganic photochromic nanoparticles and a catalyst.

In the present invention, the addition of inorganic photochromic nanoparticles can achieve the purpose of adaptive light intensity adjustment. The transparency will change with the light intensity. When the light intensity is strong, the transparency decreases and the light transmission decreases. When the light intensity decreases, , the transparency gradually recovers, and the polymer, as the main component of the smart window foil, has the effect of dispersing the photochromic material, avoiding the local scattering of light caused by aggregation due to uneven dispersion. Therefore, the joint effect of the two Under this circumstance, smart window foil achieves better adaptive light intensity effect.

The photochromic material provided by the present invention includes two different states: colorless state and colored state. Under different light intensities, the photochromic material can present different states. Take tungsten trioxide as an example. When tungsten trioxide is in the oxidized state, due to its wide bandgap semiconductor material characteristics, it absorbs light in the ultraviolet light band and has no absorption in the visible light band, making the smart window foil transparent. When oxidized tungsten trioxide absorbs ultraviolet light, a pair of electrons and holes are generated. The electrons are re-injected into the interior of tungsten trioxide and captured by oxygen vacancies to generate reduced W ⁵⁺ . The holes are captured by water in the air to form O ₂ and H ⁺ , H ⁺ are embedded in the tungsten trioxide lattice to form HWO ₃ , that is, reduced tungsten trioxide. The reduced tungsten trioxide forms an F color center due to oxygen vacancies capturing electrons, and a large number of free electrons. Scattering will have strong absorption of visible light and infrared light, making the smart window foil colored. When the reduced tungsten trioxide stops being irradiated by ultraviolet light, the oxygen in the air will slowly oxidize the reduced tungsten trioxide, returning it from W ⁵⁺ to W ⁶⁺ , and the corresponding H ⁺ will move from the tungsten trioxide crystal lattice It is released from the film to generate WO ₃ and water, that is, the reverse reaction of the photochromic reaction occurs, and the smart window foil returns from the colored state to the transparent state.

In the present invention, the inorganic photochromic material is nanoscale, and its particle size is 2 to 10 nm.

Further, the weight ratio of the inorganic photochromic material to the polymer is 5wt% to 10wt%.

Further, the weight ratio of the catalyst to the inorganic photochromic material is 0wt% to 10wt%.

In order to better realize the effect of smart window foil adapting to light intensity, the inventor screened out a catalyst that matches the inorganic photochromic material through a large number of experiments. The addition of the catalyst mainly affects the photochromic material from a colored state to a colorless state. The recovery rate will in turn affect the sensitivity of the smart window foil to the adaptive nature of light, improve the sensitivity of the adaptive nature of light, and shorten the recovery time after discoloration. When no catalyst is added, oxygen in the air is required to slowly oxidize to achieve the fading of the smart window foil. When the catalyst is introduced, it can promote the fading process and accelerate the recovery process of the photochromic material. However, those skilled in the art can understand that the discoloration process and fading process of smart window foils are in a competitive relationship. Although adding a catalyst can shorten the recovery rate after discoloration, it will reduce the discoloration rate. Of course, this field has Technicians can choose whether to add a catalyst as needed.

When there is a catalyst in the system, taking copper chloride as an example, during the photochromic reaction, part of the generated photoelectrons are captured by the oxygen vacancies of tungsten trioxide, and part of them are absorbed by Cu ²⁺ to form Cu ⁺ , ^which is not The stable intermediate valence state is more easily oxidized by oxygen in the air to form Cu ²⁺ , and Cu ²⁺ will absorb the electrons captured by the oxygen vacancies of tungsten trioxide and promote the fading process.

Specifically, when tungsten trioxide absorbs ultraviolet light, W ⁶⁺ is reduced to W ⁵⁺ and Cu ²⁺ is reduced to Cu ⁺ . When the light intensity becomes weaker, Cu ⁺ and W ⁵⁺ are oxidized back to The Cu ²⁺ and W ⁶⁺ states allow the smart window foil to quickly recover from the colored reduction state to the colorless oxidation state. In some preferred embodiments, the weight ratio of copper chloride to tungsten trioxide is 0 wt% to 10 wt%. Further preferably, the weight ratio of lithium iodide to tungsten trioxide includes but is not limited to 4wt%, 5wt%, 6wt%, etc.

Moreover, the doping amount of photochromic nanomaterials will affect the initial transparency and discoloration effect of smart window foils. Taking tungsten trioxide and polymethyl methacrylate as an example, when the weight ratio of tungsten trioxide to polymethyl methacrylate exceeds 10wt%, significant aggregation will occur in the formed smart window foil, resulting in the deterioration of the entire film. Transparency and uniformity are reduced. When the weight ratio of tungsten trioxide to polymethyl methacrylate is less than 2 wt%, ultraviolet light has almost no photochromic effect. In some preferred embodiments, the weight ratio of the tungsten trioxide to polymethyl methacrylate is 5 wt% to 10 wt%. Further preferably, the weight ratio of tungsten trioxide to polymethyl methacrylate includes but is not limited to 7.5 wt%, etc.

Further, the absorption band of the tungsten trioxide nanoparticles is 250 to 400 nm.

The thickness of the smart window foil is related to the solution concentration and the thickness of the liquid film during the coating process. In order to ensure the good practicality and production cost of the smart window foil, the thickness of the smart window foil is set to 20 μm ~ 40 μm.

In order to achieve the above second purpose, the present invention adopts the following technical solutions:

The invention discloses a preparation method for intelligent window foil with adaptive light intensity as described above, which includes the following steps:

Dissolve the precursor of photochromic inorganic nanoparticles in N,N-dimethylformamide and stir to form a sol. Then add the sol to the dichloroethane solution containing the polymer. After stirring evenly, use coating Using this method, the solution is evenly applied on the glass substrate, and after drying, it is demoulded to obtain a smart window foil that can adapt to light intensity.

The formation of photochromic inorganic nanoparticles directly affects the performance of smart window foils that can adapt to light intensity. Traditional nanoparticle preparation processes, such as hydrothermal methods and ball milling methods, are not suitable for preparing smart window foils in the present invention. On the one hand, these processes consume high energy, are complex to operate, and have certain risks; on the other hand, the prepared photochromic inorganic nanoparticles have large particle sizes, have no obvious discoloration effect, and have poor compatibility with the polymer matrix. Aggregation easily occurs in materials. More importantly, the present invention is not only for preparing photochromic inorganic nanoparticles, but also requires a method that can form photochromic inorganic nanoparticles under a smart window foil preparation system. Overcome the problem of being unable to prepare a smart window foil that meets the requirements, that is, a transparent and flexible smart window foil cannot be obtained by directly mixing photochromic inorganic nanoparticles and polymers, and the automatic smart window foil cannot be realized only under changes in light intensity. The problem of the change of color from colorless and transparent to colored. The solution supersaturation method can be used to convert the precursor chloride into photochromic inorganic nanoparticles in the smart window foil preparation system, and be well dispersed in the polymer to form a solid sol, realizing the transition from an organic sol to a polymer solid. The transformation of the sol not only reduces the preparation process and costs, but also avoids the scattering of light caused by excessive size or aggregation of nanoparticles. The most important thing is that it has a good photochromic effect.

The solution supersaturation method refers to a method of preparing a sol by utilizing the widely different solubilities of the same substance in different solvents. The precursor chloride of the photochromic inorganic nanoparticles in the present invention can be well dissolved in N,N-dimethylformamide, but has poor solubility in polymers. After drying the solvent, it can be obtained Uniformly dispersed photochromic inorganic nanoparticle-polymer solid sol.

In a specific embodiment, tungsten chloride is selected as the precursor of tungsten trioxide; copper chloride is selected as the catalyst; preferably, the concentration of tungsten chloride in the sol is 0.1 to 0.3g/mL, and the copper chloride The concentration is 0.02-0.03g/mL; preferably, the concentration of polymethylmethacrylate in the polymethylmethacrylate solution is 0.2-0.6g/mL.

Further, the stirring time is 1 to 3 hours.

Further, the drying temperature is 50-70°C; the drying temperature is 1-4 hours. When choosing the drying temperature, the evaporation rate of the solvent is mainly considered, because in the process of preparing solid sol smart window foil using the solution supersaturation method, the rapid evaporation of the solvent is the key to affecting the transparency of the smart window foil. The evaporation time of the solvent is too long. If the evaporation rate is too long, the nanoparticles will have a greater probability of collision and aggregation during the film formation process, which will eventually cause the smart window foil to scatter light. However, if the volatilization rate is too fast, volatilized pores will be formed on the smart window foil when the solvent is removed. , this will also cause the smart window foil to scatter light and affect the transmittance of the smart window foil. Therefore, the drying temperature is controlled at 50 to 70°C to ensure that the drying process is completed within 1 to 4 hours. In the specific implementation , the set drying temperature is 60℃ and the drying time is 1h.

In order to achieve the above third purpose, the present invention discloses an application in adjusting the solar transmittance using the above intelligent window foil that can adapt to the light intensity.

When strong sunlight or light from a solar simulator irradiates the smart window foil with adaptive light intensity provided by the present invention, the transparency of the smart window foil is reduced and the light transmission is reduced. Specifically, when tungsten trioxide is irradiated by a solar simulator (100mW/cm ² ) for 5 minutes, the transparent and colorless smart window foil turns blue, and the color deepens as the irradiation time increases. When the sunlight simulator is turned off, the blue color of the smart window foil will slowly disappear under dark conditions, and the smart window foil will return to a colorless state.

The invention has the following advantages:

The invention discloses an intelligent window foil that can adapt to light intensity, its preparation and application. The smart window foil contains polymers, photochromic inorganic nanoparticles and catalysts, where the photochromic inorganic nanoparticles include a colorless oxidation state and a colored reduction state. After absorbing sunlight, the photochromic inorganic nanoparticles convert from a colorless oxidation state to a colored reduction state, allowing the smart window foil to adapt to the intensity of sunlight to appear light or dark. Doping the catalyst will affect the recovery rate of the photochromic inorganic nanoparticles, thereby affecting the adaptive sensitivity of the smart window foil to light. This smart window foil is transparent in its own oxidized state and in its colored reduced state, and can be attached to existing window glass without replacing the existing window. It is easy to use, flexible, self-supporting, and low cost. It has the advantages of no scattering, more energy saving and environmental protection, and has broad application prospects.

Description of the drawings

Figure 1 is a schematic structural diagram of a smart window foil that can adapt to light intensity;

Figure 2 is a flow chart of Embodiment 2 of a method for preparing a smart window foil that can adapt to light intensity;

Figure 3 is a flow chart of Embodiment 3 of a method for preparing a smart window foil that can adapt to light intensity;

Figure 4 is a schematic process diagram of the preparation method of

embodiments

4 and 5 of an intelligent window foil that can adapt to light intensity;

Figure 5a is a schematic diagram of the macroscopic transparency of the smart window foil before sunlight irradiation in Example 4 of a method for preparing an intelligent window foil that can adapt to light intensity;

Figure 5b is a schematic diagram of the macroscopic transparency of the smart window foil after sunlight irradiation in Example 4 of a method for preparing an intelligent window foil that can adapt to light intensity;

Figure 5c is a diagram showing the change in transmittance of the smart window foil before and after under light irradiation in Example 4 of a method for preparing an intelligent window foil that can adapt to light intensity;

Figure 6a is a schematic diagram of the macroscopic transparency of the smart window foil before sunlight irradiation in Example 5 of a method for preparing an intelligent window foil that can adapt to light intensity;

Figure 6b is a schematic diagram of the macroscopic transparency of the smart window foil after sunlight irradiation in Example 5 of a method for preparing an intelligent window foil that can adapt to light intensity;

Figure 6c is a diagram showing the change in transmittance of the smart window foil before and after under light irradiation in Example 5 of a method for preparing an intelligent window foil that can adapt to light intensity;

Figure 7a is a schematic diagram of the transmittance of the smart window foil in Examples 4 and 5 of Examples 4 and 5 of a method for preparing an intelligent window foil that can adapt to light intensity under a 365 nm ultraviolet lamp of 100 mW·cm ^-2 for 0 seconds;

Figure 7b is a schematic diagram of the transmittance of the smart window foil in Examples 4 and 5 of Examples 4 and 5 of a method for preparing an intelligent window foil with adaptive light intensity when illuminated under a 365nm ultraviolet lamp of 100 mW·cm ^-2 for 1 minute;

Figure 7c is a schematic diagram of the transmittance of the smart window foil in Examples 4 and 5 of Examples 4 and 5 of a method for preparing an intelligent window foil with adaptive light intensity when illuminated under a 365nm ultraviolet lamp of 100 mW·cm ^-2 for 2 minutes;

Figure 7d is a schematic diagram of the transmittance of the smart window foil in Examples 4 and 5 of a method for preparing an intelligent window foil with adaptive light intensity when illuminated under a 365nm ultraviolet lamp of 100 mW·cm ^-2 for 3 minutes;

Figure 7e is a schematic diagram of the transmittance of the smart window foil in Examples 4 and 5 of a method for preparing an intelligent window foil with adaptive light intensity when illuminated under a 365nm ultraviolet lamp of 100 mW·cm ^-2 for 4 minutes;

Figure 7f is a schematic diagram of the transmittance of the smart window foil in Examples 4 and 5 of Examples 4 and 5 of a method for preparing an intelligent window foil with adaptive light intensity when illuminated under a 365nm ultraviolet lamp of 100 mW·cm ^-2 for 5 minutes;

Figure 7g is a schematic diagram of the transmittance of the smart window foil in Examples 4 and 5 of Examples 4 and 5 of a method for preparing an intelligent window foil with adaptive light intensity when illuminated under a 365nm ultraviolet lamp of 100 mW·cm ^-2 for 10 minutes;

Figure 7h is a schematic diagram of the transmittance of the smart window foil in Examples 4 and 5 of a method for preparing an intelligent window foil with adaptive light intensity when illuminated under a 365nm ultraviolet lamp of 100 mW·cm ^-2 for 15 minutes;

Figure 7i is a graph showing the change in transmittance at 1050nm of the smart window foil in Examples 4 and 5 of a method for preparing an intelligent window foil that can adapt to light intensity under a 365nm ultraviolet lamp of 100mW·cm ^-2 ;

Figure 8a is a schematic diagram of the transmittance of the smart window foil in Examples 4 and 5 of the smart window foil fading recovery process at 0 min of a method for preparing an adaptive light intensity smart window foil;

Figure 8b is a schematic diagram of the transmittance of the smart window foil in Examples 4 and 5 of a method for preparing an intelligent window foil that can adapt to light intensity for 10 minutes during the smart window foil fading recovery process;

Figure 8c is a schematic diagram of the transmittance of the smart window foil in Examples 4 and 5 of the intelligent window foil preparation method with adaptive light intensity for 20 minutes during the smart window foil fading recovery process;

Figure 8d is a schematic diagram of the transmittance of the smart window foil in Examples 4 and 5 of the smart window foil fading recovery process for 30 minutes of a method for preparing an adaptive light intensity smart window foil;

Figure 8e is a schematic diagram of the transmittance of the smart window foil in Examples 4 and 5 of the smart window foil fading recovery process for 40 minutes of a method for preparing an adaptive light intensity smart window foil;

Figure 8f is a schematic diagram of the transmittance of the smart window foil in Examples 4 and 5 of the intelligent window foil preparation method for adaptive light intensity for 50 minutes during the smart window foil fading recovery process;

Figure 8g is a schematic diagram of the transmittance of the smart window foil in Examples 4 and 5 of the smart window foil fading recovery process for 60 minutes of a method for preparing an adaptive light intensity smart window foil;

Figure 8h is a schematic diagram of the transmittance of the smart window foil in Examples 4 and 5 of a method for preparing a smart window foil that can adapt to light intensity when it returns to its original state during the smart window foil fading recovery process;

Figure 8i is a diagram showing the change in transmittance at 1050nm of the smart window foil in Examples 4 and 5 of the smart window foil preparation method with adaptive light intensity during the smart window foil fading recovery process;

Figure 9 is a transmission electron microscope image of a smart window foil that can adapt to light intensity and its preparation method and application embodiment 4.

Figure 10 is a transmission electron microscope image of a smart window foil that can adapt to light intensity and its preparation method and application example 5.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention.

Example 1

As shown in Figure 1, a smart window foil that can adapt to light intensity. The components of the smart window foil include a carrier and photochromic inorganic nanoparticles;

Photochromic inorganic nanoparticles have an oxidation state and a reduction state. The oxidation state is a colorless state and the reduction state is a colored state. Photochromic inorganic nanoparticles are used to convert from the oxidation state to the reduction state after absorbing sunlight to make smart window foils The color of the smart window foil adapts to the sunlight intensity from light to dark. The photochromic inorganic nanoparticles are used to convert from the reduced state to the oxidation state when the sunlight cannot be absorbed, so that the color of the smart window foil adapts to the sunlight intensity from dark to light. Reach colorless state;

The components of the smart window foil also include a catalyst, which is used to regulate the conversion rate of the photochromic inorganic nanoparticles from the reduced state to the oxidized state;

The particle size of the photochromic inorganic nanoparticles is 2 to 10 nm, the weight ratio of the photochromic inorganic nanoparticles to the polymer is 5 to 10%, and the light absorption band of the photochromic inorganic nanoparticles is 250 to 400 nm;

The material of the carrier is a polymer, which is colorless and transparent. The polymer is any one of the following: polymethyl methacrylate, polycarbonate and polystyrene;

Photochromic inorganic nanoparticles are wide bandgap semiconductor materials;

Smart window foil is a transparent sheet structure, and the thickness of smart window foil is 20~60μm;

The catalyst is any one of the following: platinum, copper chloride and chromium chloride, and the weight ratio of the catalyst to the photochromic inorganic nanoparticles is 0 to 10%.

Example 2

As shown in Figure 2, a method for preparing a smart window foil that can adapt to light intensity includes the following steps:

S1. Preparing the sol: Dissolve the precursor of the photochromic inorganic nanoparticles in the first solvent and stir to obtain the sol; you can also dissolve the precursor and the catalyst of the photochromic inorganic nanoparticles in the first solvent and stir to obtain the sol. ,;

The precursor of the photochromic inorganic nanoparticles includes tungsten chloride, the first solvent is N,N-dimethylformamide, the concentration of the photochromic inorganic nanoparticles in the sol is 0.1-0.3g/mL, and the stirring time is 1～3h;

The second solvent is dichloroethane, and the concentration of the polymer in the second solvent is: 0.2~0.6g/mL;

S3. Preparation of smart window foil: Use the coating method to evenly apply the solid solution on the glass substrate. After drying and demoulding, a smart window foil that can adapt to the light intensity is obtained; the drying temperature is 40-70°C. , the drying time is 1 to 4 hours.

Example 3

As shown in Figure 3, a method for preparing a smart window foil that can adapt to light intensity includes the following steps:

S1. Preparing the sol: Dissolve the precursor and catalyst of the photochromic inorganic nanoparticles in the first solvent, and stir to obtain the sol; you can also dissolve the precursor and the catalyst of the photochromic inorganic nanoparticles in the first solvent and stir. A sol is obtained, and the concentration of the catalyst in the sol is 0.02~0.03g/mL;

Example 4

As shown in Figure 4, a method for preparing a smart window foil that can adapt to light intensity includes the following steps:

Dissolve 0.3g tungsten chloride (WCl ₆ ) and 0.015g copper chloride (CuCl ₂ ) in 1.5ml N,N-dimethylformamide (DMF), stir at room temperature for 2 hours to form a sol, and set aside;

Dissolve 4g polymethylmethacrylate (PMMA) in dichloroethane, the concentration of PMMA is 0.4g·ml ^-1 , stir at 60 degrees Celsius for 2h, and set aside;

Add the sol to the PMMA dichloroethane solution, stir at room temperature for 2 hours, pour it on the glass substrate on the surface of the coater, set the liquid film thickness to 200 microns, the glass substrate temperature to 60°C, and dry for 1 hour. After demoulding, a smart window foil (Cu-WO ₃ /PMMA) that can adapt to illumination can be obtained. The thickness of the smart window foil is 40 μm.

Example 5

Dissolve 0.3g tungsten chloride (WCl ₆ ) in 1.5ml N,N-dimethylformamide (DMF), stir at room temperature for 2h to form a sol, and set aside;

Add the sol to the PMMA dichloroethane solution, stir at room temperature for 2 hours, pour it on the glass substrate on the surface of the coater, set the liquid film thickness to 200 microns, the glass substrate temperature to 70°C, and dry for 1 hour. After demoulding, a smart window foil (WO ₃ /PMMA) that can adapt to illumination can be obtained. The thickness of the smart window foil is 40 μm.

Example 6

Dissolve 0.14g titanium tetrachloride (TiCl ₄ ) and 0.015g copper chloride (CuCl ₂ ) in 1.5ml N,N-dimethylformamide (DMF), stir at room temperature for 2 hours to form a sol, and set aside;

Add the sol to the PMMA dichloroethane solution, stir at room temperature for 2 hours, pour it on the glass substrate on the surface of the coater, set the liquid film thickness to 200 microns, the glass substrate temperature to 50°C, and dry for 1 hour. After demoulding, a smart window foil (Cu-TiO ₂ /PMMA) that can adapt to illumination can be obtained. The thickness of the smart window foil is 40 μm.

Example 7

Dissolve 0.20g molybdenum chloride (MoCl ₅ ) and 0.015g copper chloride (CuCl ₂ ) in 1.5ml N,N-dimethylformamide (DMF), stir at room temperature for 2 hours to form a sol, and set aside;

Add the sol to the PMMA dichloroethane solution, stir at room temperature for 2 hours, pour it on the glass substrate on the surface of the coater, set the liquid film thickness to 200 microns, the glass substrate temperature to 60°C, and dry for 1 hour. After demoulding, a smart window foil (Cu-MoO ₃ /PMMA) that can adapt to illumination can be obtained. The thickness of the smart window foil is 40 μm.

Example 8

Dissolve 4g polycarbonate (PC) in dichloroethane, the concentration of PC is 0.4g·ml ^-1 , stir at 60 degrees Celsius for 2 hours, and set aside;

Add the sol to the dichloroethane solution of PC, stir for 2 hours at room temperature, and pour it onto the glass substrate on the surface of the coater. Set the liquid film thickness to 200 microns, the glass substrate temperature to 50°C, and dry for 1 hour. After demoulding, a smart window foil (Cu-WO ₃ /PC) that can adapt to illumination can be obtained. The thickness of the smart window foil is 40 μm.

Example 9

Dissolve 4g polystyrene (PS) in dichloroethane, the concentration of PS is 0.4g·ml ^-1 , stir at 70 degrees Celsius for 2 hours, and set aside;

Add the sol to the dichloroethane solution of PC, stir for 2 hours at room temperature, pour it on the glass substrate on the surface of the coater, set the liquid film thickness to 200 microns, the glass substrate temperature to 60°C, and dry for 1 hour. After demoulding, a smart window foil (Cu-WO ₃ /PS) that can adapt to illumination can be obtained. The thickness of the smart window foil is 40 μm.

The smart window foils of Examples 4 to 5 were placed under sunlight for 10 minutes, and the transparency changes are shown in Figures 5a, 5b, 6a, and 6b. It can be found that the smart window foil is completely transparent before illumination, which is recorded as a colorless state. After illumination, the color of the film becomes darker, and the light transmittance decreases significantly, which is recorded as a colored state. As shown in Figures 5c and 6c, the transmission spectrum and reflection spectrum of the smart window foil show that the colorless smart window foil only absorbs ultraviolet light, while the colored smart window foil absorbs ultraviolet, visible and infrared light. All have strong absorption. The smart window foil was placed under a solar simulator and irradiated with a power of 100 mW·cm ^-2 for 15 minutes. The coloring process and the transparency changes during the fading recovery process are shown in Figures 7a to 7h and 8a to 8h. It can be found that both The transparency slowly decreases with the illumination time, and the transparency gradually recovers with time after no illumination. It can be seen that the Cu-WO ₃ /PMMA smart window foil doped with the catalyst copper chloride takes about 1 hour to fade, while without the catalyst Copper chloride's WO ₃ /PMMA smart window foil hardly fades after 1 hour. The change of transmittance at 1050nm with illumination time during the discoloration and fading process is shown in Figure 7i and Figure 8i. The smart window foil was placed under 365nm ultraviolet light and irradiated with a power of 5mW·cm ^-2 for 180s. The transmittance Slowly decreases with the irradiation time. After turning off the light source, the transmittance of Cu-WO ₃ /PMMA smart window foil doped with catalyst copper chloride slowly returns to the initial state within 1 hour, while that of WO ₃ without doped copper chloride catalyst The transmittance of /PMMA smart window foil only returns to 40% within 1 hour.

The smart window foils of Examples 4 to 5 were sliced and observed under a transmission electron microscope. As shown in Figures 9 and 10, it can be seen that the distribution of tungsten trioxide nanoparticles in the smart window foil is about 20nm in size. .

Examples 1 to 2 and 6 to 9 can also achieve the same effect.

Example 10

An application of smart window foil that can adapt to light intensity and is used to adjust the transmittance of sunlight.

The above are only preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person familiar with the technical field can, within the technical scope disclosed in the present invention, implement the technical solutions of the present invention. Equivalent substitutions or changes of the inventive concept thereof shall be included in the protection scope of the present invention.

Claims

A smart window foil that can adapt to light intensity, characterized by: including a carrier and photochromic inorganic nanoparticles;

The carrier is used to uniformly distribute the photochromic inorganic nanoparticles;

The photochromic inorganic nanoparticles have an oxidation state and a reduction state, the oxidation state is a colorless state, and the reduction state is a colored state. The photochromic inorganic nanoparticles are used to absorb sunlight and then absorb sunlight from the oxidation state. The photochromic inorganic nanoparticles are used to convert from the reduced state to the oxidized state when the sunlight cannot be absorbed. state so that the color of the smart window foil adapts to the intensity of sunlight from dark to light until it reaches a colorless state.
A smart window foil that can adapt to light intensity according to claim 1, characterized in that: the components of the smart window foil also include a catalyst, and the catalyst is used to adjust the photochromic inorganic nanoparticles from The conversion rate of the reduced state to the oxidized state.
A smart window foil that can adapt to light intensity according to claim 1, characterized in that: the photochromic inorganic nanoparticles are wide bandgap semiconductor materials;

The photochromic inorganic nanoparticles are any one of the following: titanium dioxide, tungsten trioxide and molybdenum trioxide;

The material of the carrier is a polymer, and the polymer is colorless and transparent;

The smart window foil is a transparent sheet structure.
A smart window foil that can adapt to light intensity according to claim 1, characterized in that: the particle size of the photochromic inorganic nanoparticles is 2 to 10 nm, and the photochromic inorganic nanoparticles and the The weight ratio of the polymer is 5 to 10%, and the light absorption band of the photochromic inorganic nanoparticles is 250 to 400 nm;

The carrier is any one of the following: polymethyl methacrylate, polycarbonate and polystyrene;

The thickness of the smart window foil is 20-60 μm.
A smart window foil with adaptive light intensity according to claim 2, characterized in that: the catalyst is any one of the following: platinum, copper chloride and chromium chloride, and the catalyst is in contact with the photoinduced The weight ratio of the color-changing inorganic nanoparticles is 0 to 10%.
The method for preparing an intelligent window foil with adaptive light intensity according to any one of claims 1, 3 to 4, characterized in that it includes the following steps:

S1. Preparing the sol: Dissolve the precursor of the photochromic inorganic nanoparticles in the first solvent and stir to obtain the sol;

S2. Prepare solid sol: add the sol to a second solvent containing a polymer. The solubility of the photochromic inorganic nanoparticles in the first solvent is greater than the solubility in the polymer. Through the solution The supersaturation method is used to disperse the photochromic inorganic nanoparticles in the polymer to obtain a solid sol;

S3. Preparing smart window foil: Use a coating method to evenly apply the solid solution on the glass substrate, dry and demould to obtain a smart window foil that can adapt to light intensity.
The method for preparing an intelligent window foil with adaptive light intensity according to claim 6, characterized in that: in step S1, the first solvent is N,N-dimethylformamide, and the photoinduced The concentration of the color-changing inorganic nanoparticles in the sol is 0.1-0.3g/mL, and the stirring time is 1-3h;

In step S2, the second solvent is dichloroethane, and the concentration of the polymer in the second solvent is: 0.2-0.6g/mL;

In step S3, the drying temperature is 40-70°C, and the drying time is 1-4 hours.
The method for preparing an intelligent window foil with adaptive light intensity according to any one of claims 2, 3 to 5, characterized in that it includes the following steps:

S1. Preparing the sol: Dissolve the precursor and catalyst of the photochromic inorganic nanoparticles in the first solvent, and obtain the sol after stirring;

S2. Prepare solid sol: add the sol to a second solvent containing a polymer. The solubility of the photochromic inorganic nanoparticles in the first solvent is greater than the solubility in the polymer. Through the solution The supersaturation method is used to disperse the photochromic inorganic nanoparticles in the polymer to obtain a solid sol;

S3. Preparing smart window foil: Use a coating method to evenly apply the solid solution on the glass substrate, dry and demould to obtain a smart window foil that can adapt to light intensity.
The method for preparing an intelligent window foil with adaptive light intensity according to claim 8, characterized in that: in step S1, the first solvent is N,N-dimethylformamide, and the photoinduced The concentration of the color-changing inorganic nanoparticles in the sol is 0.1~0.3g/mL, the concentration of the catalyst in the sol is 0.02~0.03g/mL, and the stirring time is 1~3h;

In step S2, the second solvent is dichloroethane, and the concentration of the polymer in the second solvent is: 0.2-0.6g/mL;

In step S3, the drying temperature is 40-70°C, and the drying time is 1-4 hours.
The application of an intelligent window foil that can adapt to light intensity according to any one of claims 1 to 9, characterized in that the intelligent window foil is used to adjust the transmittance of sunlight.