CN101613187B - A Method for Improving the Gas-induced Cycle Performance of WO3 Membrane - Google Patents

Abstract

The invention belongs to the technical field of environmental protection and energy-saving materials, and relates to a method for improving the aerochromic cycle performance of a WO ₃ thin film. The WO ₃ sol is doped with inorganic substances that can increase the porosity of the WO ₃ aerochromic thin film. The inorganic Compounds include SiO ₂ , Al ₂ O ₃ , P ₂ O ₅ , Fe ₂ O ₃ , CuO ₂ . The stable WO ₃ composite sol was prepared by the Sol-gel method; a transparent and uniform composite WO ₃ porous film doped with catalyst was plated on ordinary glass by the pulling method or the spin coating method. Compared with the untreated film, the aerochromic thin film prepared by doping and compounding the sol of the present invention greatly improves the cycle of aerochromic color; compared with the aerochromic thin film prepared by magnetron sputtering, etc. The performance is the same, and the cost will be significantly lower; compared with the electrochromic film, it also has the same advantages. The invention well makes up for the shortcomings of the aerochromic smart windows prepared by the sol-gel method, and makes the technology of such smart windows more mature.

Description

A Method for Improving the Gas-induced Cycle Performance of WO3 Membrane

technical field

The invention belongs to the technical field of environmental protection and energy-saving materials, and relates to the gas-induced color change technology of _WO3 thin film, especially a method for improving the gas-induced cycle performance of _WO3 thin film.

Background technique

At present, energy shortage has become an issue of increasing concern to governments at all levels, and the use of clean, renewable, safe and reliable energy is imminent. Buildings are one of the units with high energy consumption. In my country, their energy consumption has reached 27.6% of the total energy consumption of the society and will exceed 33%. 40% of the energy loss is caused by windows, which is 2-3 times that of developed countries. . According to statistics, under heating or air conditioning conditions, the heat lost by single glass windows in winter accounts for about 30-50% of the heat load, and in summer, the cooling energy consumed due to solar radiation heat entering the room through glass windows accounts for about 20% of the air conditioning load. -30%. Therefore, the comprehensive utilization of new energy-saving materials and energy-saving technologies and solar energy has been brought to the agenda. If the window glass with high energy consumption is coated with a layer of transparent thermal insulation film material, energy can be effectively saved. According to the estimate of MIT in the United States, the heat loss of single-layer glass windows (without coating) is about 7 US dollars/m ² per year. If a layer of transparent heat insulation film material is coated on the glass, the heat loss of the window can be reduced to about 3.2 per year. USD/m ² . According to the estimates of Uppsala University in Sweden, under the climatic conditions in central Europe, coating a layer of transparent thermal insulation film on the window glass can save energy by 20% in the home and 12% in the office.

As early as the 1980s, Europe, the United States, Japan, China and other countries carried out research on transparent thermal insulation and energy-saving film materials, and achieved good applications in modern buildings (ie glass curtain walls), achieving better energy saving effect. However, this material has a single function and fixed spectral characteristics. Regardless of whether it is sunny or daytime, indoor lighting is still used, people cannot enjoy the sunlight of nature, and energy saving in summer consumes energy in winter; conversely, energy saving in winter consumes energy in summer. For the temperate zone where we live, its optical characteristics and energy-saving characteristics cannot be adjusted with the changes of seasons and day and night. Therefore, in order to provide a comfortable living and working environment, people have long been looking for a coating that can be intelligently controlled, whose optical properties can change reversibly with changes in the external environment, and that integrates energy saving, decoration, heat insulation, and heat preservation. glass material. The birth of the chromogenic smart window can solve this problem.

Chromogenic smart windows can intelligently control the sunlight passing through the windows dynamically, reversibly and arbitrarily, and can be widely used in buildings, automobiles, spaceships, etc. It provides a new design method for the manufacture of modern energy-saving window systems.

Generally, chromogenic smart windows are divided into thermochromic, photochromic, and electrochromic. In terms of the form of action, photochromism and thermochromism are passive color-changing materials, which only change color when external conditions such as light intensity and temperature change, and people cannot flexibly control them. The electrochromic material is an active functional material. Its optical properties (such as transmittance, color) can be changed according to the surrounding environment. , reversible, and arbitrarily changed, so that the optical density can be continuously adjusted. Therefore, it has the most practical application prospects. Developed countries such as the United States, Japan, and Europe, as well as many domestic units, are conducting commercial application research, but this color-causing smart window Usually composed of five layers of thin film materials, the structure of the device is complex, there are many influencing factors, the preparation cost is high, and it is difficult to produce on a large scale. Although this electrochromic material already has small-sized commercial products such as car mirrors and sunglasses, it has not been commercially applied as a large-sized building energy-saving window.

In recent years, the latest research on chromogenic materials in the world shows that a color-changing material with a similar color-changing mechanism to electrochromism—aerochromic film is attracting great interest. This chromogenic smart window is only composed of a chromogenic film and an extremely thin catalyst layer or a chromogenic film containing a catalyst. Gas molecules (such as hydrogen) are decomposed into atoms by the catalyst and enter the chromogenic film through diffusion. Changes in optical properties are caused in the material, resulting in continuous, reversible, and arbitrary changes in the transmittance of the thin film material. The chromogenic material with a solid-state structure has a simple structure, fewer influencing factors, and a wider optical adjustment range, which is convenient for large-scale production, and the device operates without energy consumption. This new type of aerochromic smart window was first proposed and developed by the Fraunhofer Institute for Solar Energy Systems in Germany, and then universities and research institutes in a few countries such as the United States and Slovenia have carried out work in this area. At present, only Tongji University and the Guangzhou Institute of Solar Energy Research of the Chinese Academy of Sciences have carried out research in this area in China.

In principle, the electrochromic smart window device is that small cations and electrons are double-injected and extracted from the chromogenic film under the action of an electric field, resulting in electrochromic and fading effects. For gasochromic smart window devices, hydrogen molecules are decomposed into hydrogen atoms after being acted on by catalysts, which diffuse into the chromogenic film to produce a color-causing effect, and when oxygen atoms or air diffuse into the film, fading occurs. Therefore, both hydrogen Different injection/exit drive mechanisms require different microstructural properties of thin film materials.

At present, in the world, the most promising aerochromic properties of amorphous WO ₃ thin film materials are mainly studied, and how to improve the hydrogen atom diffusion rate and diffusion rate of aerochromic window devices made of amorphous WO ₃ thin film materials. Issues of uniformity, color consistency, rate of color change, durability, etc. are being intensively studied.

The sol of SiO ₂ or P ₂ O ₅ , Al ₂ O ₃ , Fe ₂ O ₃ and other relatively hydrogen-stable materials is a common and cheap material. The film prepared from this material has the advantages of low raw material, simple preparation process, physical and chemical Features such as stable performance.

At present, there is no relevant patent report on improving the aerochromic performance of amorphous WO ₃ thin film material by using WO3/SiO2 two-phase dispersed doping technology.

Contents of the invention

The object of the present invention is to provide a method for improving the gas-induced cycle performance of the WO ₃ film.

A method for improving the gas-induced cycle performance of WO ₃ thin film, the WO ₃ sol is doped with inorganic substances that can increase the porosity of WO ₃ aerochromic thin films, and the inorganic substances include SiO ₂ , Al ₂ O ₃ /AAO templates , P ₂ O ₅ , Fe ₂ O ₃ , CuO ₂ .

Further: Include the following steps:

Preparation of WO ₃ sol;

Selection and preparation of SiO ₂ and Al ₂ O ₃ sols;

Preparation of catalyst-doped WO ₃ /SiO ₂ , WO ₃ /Al ₂ O ₃ sols:

Catalyst-doped WO ₃ /SiO ₂ and WO ₃ /Al ₂ O ₃ films were prepared.

Preparation of WO ₃ sol:

Using the sol-gel method, under normal temperature and pressure, tungsten powder and hydrogen peroxide solution were stirred and reacted for 50-70 minutes, the molar ratio of tungsten powder and hydrogen peroxide was 1:3-1:4, centrifuged and filtered to obtain Light yellow transparent solution; then add absolute ethanol to the resulting solution, the amount of absolute ethanol added is 1/2 to 4/5 of the volume of the container, and reflux in an oil bath at 75-85°C for 1.5-2 hours until the sol is transformed into Orange yellow, that is, to obtain WO ₃ ethanol sol;

Preparation of SiO _sol :

The preparation process of SiO ₂ sol mainly involves the hydrolysis of silicon source, and the hydrolysis rate is very related to the ratio of silicon source, water, solution pH value and room temperature conditions. Below we recommend tetraethyl orthosilicate hydrolysis

(1) Selection and preparation of SiO ₂ sol

① Preparation of acidic catalytic SiO ₂ sol:

Use a volumetric flask and a pipette to accurately measure deionized water, absolute ethanol, and silicon source (such as tetraethyl orthosilicate). The ratio can be adjusted appropriately according to the requirements of the experimental temperature, type of silicon source, and test time. Using tetraethyl orthosilicate as the silicon source, the ratio used at room temperature is: 23.5/100/77.8 (the ratio of absolute ethanol depends on the concentration of the solution, which is adjusted accordingly to the actual required film color depth, etc., with this water The ratio to TEOS is the best ratio for film formation, and can also be adjusted according to the response of other raw materials); the ratio of deionized water to tetraethyl orthosilicate needs to be considered in combination with various factors such as water in WO3 sol, silicon source, room temperature, etc., the key The ratio is not less than the ratio of the sol-gel, and not greater than the ratio that affects the film formation of the sol.

Among them, according to the amount of deionized water taken, the concentrated hydrochloric acid (can be catalyzed by various acids, such as: tungstic acid, nitric acid, phosphoric acid, oxalic acid, etc.) In beaker A, put a clean magnetic stirring bar into beaker A; then pour the required tetraethyl orthosilicate and the required amount of anhydrous ethanol into beaker A in sequence; use cleaning film and Seal the mouth of the beaker A with a rubber band and place it on a magnetic stirrer _{for stirring. The acidic SiO 2 sol} prepared according to the above recommended ratio can be prepared after stirring for 2-4 hours. If the pH value is relatively small, it can be used relatively short stirring time.

Or ② Preparation of basic catalytic SiO ₂ sol:

The raw materials and proportions required for the preparation of SiO _sol by the basic catalytic method can be appropriately adjusted according to the requirements of the experimental temperature, type of silicon source, and test time. The recommended molar ratio is as follows: tetraethyl orthosilicate (TEOS): ethanol: ammonia water = 1 /38/2.45 (ammonia water in this ratio is the ratio of faster hydrolysis, and other ratios are also acceptable). The preparation process of the sol should be carried out in a clean environment with a relative humidity of less than 60%. The specific steps are as follows: use a volumetric flask and a pipette Use a pipette to accurately measure 1/2 of the required amount of absolute ethanol and pour it into beaker A; use a pipette to accurately measure the required amount of concentrated ammonia water with pH = 12 and pour it into beaker A (the ammonia water in this proportion is hydrolyzed The faster ratio, other ratios are also available, and the mixing with WO3 needs to reduce the amount of ammonia water as much as possible, but the pH>7 is required, and an alkaline environment is required.); Put a clean magnetic stirrer into beaker A , seal the mouth of beaker A with a clean film and a rubber band, place it on a magnetic stirrer and stir for about 20 minutes to achieve the purpose of uniform dispersion;

Use a volumetric flask and a pipette to accurately measure the required tetraethyl orthosilicate and 1/2 of the required amount of absolute ethanol and pour them into beaker B in sequence; put a clean magnetic stirring bar into beaker B, and use a clean Seal the mouth of beaker B with a film and rubber band, place it on a magnetic stirrer and stir for about 20 minutes to achieve uniform dispersion; use a magnet to take out the magnetic stirrer in beaker A along the outer wall, and pour the mixed solution in beaker A into the pear-shaped separating funnel; slowly drop the mixed solution in the pear-shaped separating funnel into the beaker B placed on the magnetic stirrer, while keeping stirring evenly; It is mixed evenly, and then the stirring bar in the beaker B is taken out along the outer wall with a magnet;

Seal the beaker B with a clean film and a rubber band and let it stand in a stable environment (16-24°C, relative humidity <50%) for aging. The aged sol is in the form of light blue latex. At this time, the particles in the sol The average particle size of the sol is less than 10nm. Take out the sol and pour it into a round bottom flask. The sol must not be immersed in more than 2/3 of the flask; add a small amount of clean molecular sieve to the round bottom flask to prevent bumping, and then fix the flask with an iron stand In a water bath heating pot with silicone oil; adjust the temperature of the oil bath between 80°C and 85°C to keep the sol liquid surface in a slightly boiling state; use a serpentine reflux tube for reflux, and use the wetted quantitative pH test paper in the reflux tube Test at the pH test paper until there is no change in the pH test paper, stop heating, and take out the flask after natural cooling; pour the sol into a beaker and seal it for storage;

Or ③ Preparation of other SiO ₂ sols

Use tetraethyl orthosilicate, methyl triethoxysilane and other silicon sources to mix with alcohol according to the required ratio (this ratio is adjusted according to the actual operation, and the value is arbitrary) to prepare a sol with a corresponding concentration.

Or ④ Preparation of Al ₂ O ₃ sol

Volumetric flask and pipette respectively accurately measure anhydrous aluminum chloride + deionized water + ethanol + propylene oxide (6mmol: 0.65ml: 6-40ml: 0.32ml); or aluminum isopropoxide + water + isopropanol + Catalyst (acid or base, take hydrochloric acid as an example), the ratio is 1mmol: 3mmol: 1-10ml: 0.1mmol (this ratio); (the above two ratios need to be considered in combination with water, aluminum source, room temperature, etc. in WO3 sol The key ratio is not less than the ratio of the sol-gel and not greater than the ratio affecting the film formation of the sol. Only recommended values can be given here. The amount of these two catalysts is the recommended ratio. The catalyst is recommended to be added dropwise. It is better to form a gel) Pour the required sol into the beaker; seal the mouth of the beaker with a cleaning film and a rubber band, place it on a magnetic stirrer for stirring, and the stirring time is 4 hours; aging at 50 degrees for 1 hour .

(3) Preparation of WO ₃ and SiO ₂ composite sol:

Add the sol obtained in step (2) to the sol obtained in step (1), and the dispersion ratio (SiO ₂ /WO ₃ molar ratio) > 0/1 has the improvement of cycle performance, and the attenuation of cycle performance is different, but when > 1/ 1 It is easier to use drying means to achieve cyclic recovery. The suggested molar ratio here is: 1/1.

(4) Preparation of catalyst-doped WO ₃ /SiO ₂ sol:

Add catalyst to the sol obtained in step (3), stir at normal temperature for 2 to 3 hours, when the sol is a reddish-brown stable sol, store it under normal pressure and zero temperature for subsequent use; the molar ratio of catalyst to tungsten powder is 1: 40～1:100, the catalyst is K ₂ [PtCl ₄ ] or PdCl ₂ ;

(5) Preparation of catalyst-doped WO ₃ film: prepared by pulling dipping method or spin coating method:

①Use the pulling and immersion plating method to prepare catalyst-doped WO ₃ thin films on the surface of glass slides or polished silicon wafers, and the pulling speed is 4-6.5cm/min;

Or: ②Use the spin coating method to prepare catalyst-doped WO ₃ film on the surface of silicon wafer or K9 glass, the pre-coating rate is 900-1100r/min, and the spin-coating rate is 2500-3500r/min;

The obtained catalyst-doped WO ₃ thin film is baked in an air atmosphere at a temperature of 50°C-250°C for 50-70 minutes.

Or ③AAO template method, immerse the 70nm Al ₂ O ₃ template in the prepared palladium-doped WO ₃ sol, vibrate in ultrasonic for 30 minutes; take out the Al ₂ O ₃ template, and place the obtained catalyst-doped WO ₃ thin film in the air , the baking temperature is 50°C-250°C, and the time is 50-70 minutes.

In order to obtain a thicker film, use the method of increasing the concentration of WO ₃ sol or the pulling speed. In the method of spin coating, the film is heat-treated at a temperature of 40-55° C. for 2-5 minutes between every two spin coatings.

WO ₃ and SiO ₂ are uniformly dispersed and compounded. The above-mentioned SiO ₂ sol preparation methods and proportions are only two examples. The SiO ₂ sol involved can use any form of SiO ₂ sol to disperse WO ₃ , such as using HNO ₃ acid, tungsten SiO ₂ is prepared by using various acids such as acid as a catalyst, or using other silicon sources.

The aerochromic performance of the obtained WO ₃ film is tested:

A UV/visible/infrared spectrophotometer (V-570, Jasco Inc.) was used to test the aerochromic performance of the UV-treated WO ₃ film mixed with catalyst. The surrounding edges of the coated glass and the uncoated glass are sealed with glass glue to form a device with a hollow (coated inside) structure, and a small hole (reserved for the introduction of hydrogen gas) is left to form an aerochromic device. When testing the aerochromic properties, argon gas with a volume content of 5% hydrogen is introduced, and a gas flow rate of 4ρ/min and an air pressure of 0.15 MPa are adopted. UV/visible/infrared spectrophotometer (V-570 type, Jasco Inc.) was used to test the transmittance of the film before and after the coloration, the wavelength range was 190-2500cm ^-1 , the wavelength accuracy was 1.5nm, and the light source in the visible light region was Halogen tungsten lamp, deuterium lamp in the ultraviolet region, automatic switching of light source.

The experimental results show that after the dispersed WO ₃ /SiO ₂ composite sol, the film WO ₃ /SiO ₂ is uniformly dispersed, and the stability of the film is improved; The entry and exit of H ₂ O becomes easier, and there is still no obvious sign of weakening after 500 cycles. An aerochromic window with good permeability and cycle performance can be prepared by adjusting the molar ratio of WO ₃ /SiO ₂ to about 1.25:1.

The method of adopting two-phase dispersed doping in the present invention is a technical method for improving the aerochromic cycle performance of the amorphous catalyst-doped _WO3 thin film material.

In the present invention, the WO ₃ sol and SiO ₂ sol prepared by the sol-gel method are dispersed and doped by the two phases according to a certain ratio to obtain a stable amorphous WO ₃ film doped with a catalyst with a large spatial pore structure, so as to make the amorphous Modification of catalyst-doped _WO3 thin film materials.

The present invention uses an ultraviolet/visible/infrared spectrophotometer (type V-570, Jasco Inc.) to test the aerochromic performance of a composite doped WO ₃ thin film doped with a catalyst. Compared with the thin film of single phase _WO3 , the aerochromic thin film prepared by the method of the present invention has greatly improved the cycle performance of aerochromic; compared with the aerochromic thin film prepared by methods such as magnetron sputtering, the performance is the same, and the cost is the same. Significantly lower; compared with electrochromic film, it also has the same advantages. The invention makes up for the shortcomings of the previous aerochromic smart windows prepared by the sol-gel method, and makes the technology of such smart windows more mature.

Description of drawings

Fig. 1 is common palladium-doped WO ₃ thin film aerochromic effect figure in embodiment 1

Fig. 2 is the aerochromic effect figure of palladium-doped WO ₃ /SiO ₂ thin film in embodiment 1

Fig. 3 is common palladium-doped WO in embodiment ₁ Circular discoloration curve of thin film

Fig. 4 is the discoloration curve of 450-500 cycles of palladium-doped WO ₃ /SiO ₂ films in Example 1

5 is a surface structure diagram of the palladium-doped WO ₃ thin film in Example 1.

Fig. 6 is the surface structure diagram of palladium-doped WO ₃ /SiO ₂ film in embodiment 1

FIG. 7 is a microscopic topography diagram of the palladium-doped WO ₃ thin film in Example 1.

Figure 8 is the microscopic topography of the palladium-doped WO ₃ /SiO ₂ film in Example 1

FIG. 9 is a schematic diagram of the circulation of the composite films with different SiO ₂ contents in Example 1.

Detailed ways

The present invention is further illustrated below by way of examples.

Embodiment 1: prepare two-phase mixed doping WO3/ _SiO2 film, concrete steps are as follows:

(1) Preparation of WO ₃ sol:

Using the sol-gel method, under normal temperature and pressure, tungsten powder and hydrogen peroxide solution were stirred and reacted for 50-70 minutes, the molar ratio of tungsten powder and hydrogen peroxide was 1:3-1:4, centrifuged and filtered to obtain Light yellow transparent solution; then add absolute ethanol to the resulting solution, the amount of absolute ethanol added is 1/2 to 4/5 of the volume of the container, and reflux in an oil bath at 75-85°C for 1.5-2 hours until the sol is transformed into Orange yellow, namely to obtain WO ₃ ethanol sol.

(2) Preparation of acidic catalytic SiO2 sol

Accurately measure deionized water, absolute ethanol (Eth), and tetraethyl orthosilicate (TEOS) with a volumetric flask and a pipette. The ratio is: 23.5/100/77.8; Measure concentrated hydrochloric acid to prepare a hydrochloric acid solution with PH=2, pour it into beaker A, put a clean magnetic stirring bar into beaker A; then accurately measure the required tetraethyl orthosilicate and the required amount of Pour absolute ethanol (Eth) into beaker A in turn; seal the mouth of beaker A with a cleaning film and a rubber band, place it on a magnetic stirrer for stirring, and the stirring time is 4 hours;

(3) Preparation of WO ₃ and SiO ₂ composite sol

Add the sol obtained in step (2) to the sol obtained in step (1), and the ratio of this sol is adjusted according to the thickness and color depth of the required film. This dispersion ratio is recommended to adopt WO3/ _SiO The molar ratio is 1.25/ 1

(4) WO3/SiO _sol of doping catalyst Preparation:

Add catalyst to the sol obtained in step (3), stir at normal temperature for 2 to 3 hours, when the sol is a reddish-brown stable sol, store it under normal pressure and zero temperature for subsequent use; the molar ratio of catalyst to tungsten powder is 1: 40～1:100, the catalyst is K ₂ [PtCl ₄ ] or PdCl ₂ ;

(5) Preparation of catalyst-doped WO ₃ film: prepared by pulling dipping method or spin coating method:

①Use the pulling and immersion plating method to prepare catalyst-doped WO ₃ thin films on the surface of glass slides or polished silicon wafers, and the pulling speed is 4-6.5cm/min;

Or: ②Use the spin coating method to prepare catalyst-doped WO ₃ film on the surface of silicon wafer or K9 glass, the pre-coating rate is 900-1100r/min, and the spin-coating rate is 2500-3500r/min;

Baking the obtained catalyst-doped WO ₃ film in an air atmosphere at a temperature of 50°C-250°C for 50-70 minutes;

The film prepared by this method has good cycle performance, and there is still no obvious attenuation after 500 cycles.

Embodiment 2: Preparation of two-phase mixed doping WO3/ _SiO2 film preparation

(1) Preparation of WO ₃ sol:

Using the sol-gel method, under normal temperature and pressure, tungsten powder and hydrogen peroxide solution were stirred and reacted for 50-70 minutes, the molar ratio of tungsten powder and hydrogen peroxide was 1:3-1:4, centrifuged and filtered to obtain Light yellow transparent solution; then add absolute ethanol to the resulting solution, the amount of absolute ethanol added is 1/2 to 4/5 of the volume of the container, and reflux in an oil bath at 75-85°C for 1.5-2 hours until the sol is transformed into Orange yellow, namely to obtain WO ₃ ethanol sol.

(2) Preparation of acidic catalytic SiO2 sol

Accurately measure deionized water, absolute ethanol (Eth), and tetraethyl orthosilicate (TEOS) with a volumetric flask and a pipette. The ratio is: 23.5/100/77.8; Measure concentrated hydrochloric acid (or nitric acid, oxalic acid, phosphoric acid) to prepare an acid solution with PH=2, pour it into beaker A, put a clean magnetic stirring bar into beaker A; then accurately measure the required orthosilicic acid Tetraethyl ester and required amount of absolute ethanol (Eth) are poured into the beaker A successively; After the mouth of the beaker A is sealed with a cleaning film and a rubber band, place it on a magnetic stirrer for stirring, and the stirring time is 4 hours;

(3) Preparation of WO ₃ and SiO ₂ composite sol

Add the sol obtained in step (2) to the sol obtained in step (1), and the ratio of this sol is adjusted according to the thickness and color depth of the required film. This dispersion ratio is recommended to adopt WO3/ _SiO The molar ratio is 1.25/ 1

(4) WO3/SiO _sol of doping catalyst Preparation:

Add catalyst to the sol obtained in step (3), stir at normal temperature for 2 to 3 hours, when the sol is a reddish-brown stable sol, store it under normal pressure and zero temperature for subsequent use; the molar ratio of catalyst to tungsten powder is 1: 40～1:100, the catalyst is K ₂ [PtCl ₄ ] or PdCl ₂ ;

(5) Preparation of catalyst-doped WO ₃ film: prepared by pulling dipping method or spin coating method:

①Use the pulling and immersion plating method to prepare catalyst-doped WO ₃ thin films on the surface of glass slides or polished silicon wafers, and the pulling speed is 4-6.5cm/min;

Or: ②Use the spin coating method to prepare catalyst-doped WO ₃ film on the surface of silicon wafer or K9 glass, the pre-coating rate is 900-1100r/min, and the spin-coating rate is 2500-3500r/min;

Baking the obtained catalyst-doped WO ₃ film in an air atmosphere at a temperature of 50°C-250°C for 50-70 minutes;

The film prepared by this method has good cycle performance, and there is still no obvious attenuation after 500 cycles.

Embodiment 3: Preparation of two-phase mixed-doped WO3/ _SiO2 film preparation

(1) Preparation of WO ₃ sol:

Using the sol-gel method, under normal temperature and pressure, tungsten powder and hydrogen peroxide solution were stirred and reacted for 50-70 minutes, the molar ratio of tungsten powder and hydrogen peroxide was 1:3-1:4, centrifuged and filtered to obtain Light yellow transparent solution; then add absolute ethanol to the resulting solution, the amount of absolute ethanol added is 1/2 to 4/5 of the volume of the container, and reflux in an oil bath at 75-85°C for 1.5-2 hours until the sol is transformed into Orange yellow, namely to obtain WO ₃ ethanol sol.

(2) Preparation of basic catalytic SiO2 sol

The raw materials and proportions (molar ratio) required for the preparation of SiO2 sol by basic catalytic method are as follows: ethyl orthosilicate (TEOS): ethanol (EtOH): ammonia water (NH3 H2O) = 1/38/2.45, the preparation process of the sol It should be carried out in a clean environment with a relative humidity of less than 60%. The specific steps are as follows: use a volumetric flask and a pipette to accurately measure 1/2 of the required amount of absolute ethanol (Eth) and pour it into beaker A; Accurately measure the required amount of concentrated ammonia water with pH = 12 and pour it into beaker A; put a clean magnetic stirring bar into beaker A, seal the mouth of beaker A with a clean film and rubber band, and place it on a magnetic Stir on a mixer for 20 minutes; use a volumetric flask and a pipette to accurately measure the required tetraethyl silicate (TEOS) and 1/2 of the required amount of absolute ethanol (Eth) and pour them into beaker B in turn ; Put a clean magnetic stirrer into beaker B, seal the mouth of beaker A with a clean film and rubber band, and place it on a magnetic stirrer for 20 minutes; Take out the stirring bar, and pour the mixed solution in the beaker A into the pear-shaped separating funnel; slowly drop the mixed solution in the pear-shaped separating funnel into the beaker B placed on the magnetic stirrer, while keeping Stir evenly; continue to stir for 2 h after the dropwise addition, and then use a magnet to take out the stirring bar in beaker B along the outer wall. Seal the beaker B with a clean film and a rubber band and place it in a stable environment (20°C, relative humidity 20%) for aging, aging time: 72h; the aged sol is in the form of light blue latex (at this time, the sol The average particle size of the inner particles is less than 10nm), take out the sol and pour it into a round bottom flask, the sol must not submerge more than 2/3 of the flask; add a small amount of clean molecular sieve into the round bottom flask to prevent bumping, and then fix the flask with an iron stand Submerged in a water bath filled with silicone oil. Adjust the temperature of the oil bath between 80°C and 85°C to keep the liquid surface of the sol in a slightly boiling state; use a serpentine reflux tube for reflux, and the reflux time depends on the amount of sol; Carry out the test, stop heating until the pH test paper has no change, take out the flask after natural cooling; pour the sol into a beaker and seal it for storage.

(3) Preparation of WO ₃ and SiO ₂ composite sol

Add the sol obtained in step (2) to the sol obtained in step (1), and the ratio of this sol is adjusted according to the thickness and color depth of the required film. This dispersion ratio is recommended to adopt WO3/ _SiO The molar ratio is 1.25/ 1

(4) WO3/SiO _sol of doping catalyst Preparation:

Add catalyst to the sol obtained in step (3), stir at normal temperature for 2 to 3 hours, when the sol is a reddish-brown stable sol, store it under normal pressure and zero temperature for subsequent use; the molar ratio of catalyst to tungsten powder is 1: 40～1:100, the catalyst is K ₂ [PtCl ₄ ] or PdCl ₂ ;

(5) Preparation of catalyst-doped WO ₃ film: prepared by pulling dipping method or spin coating method:

①Use the pulling and immersion plating method to prepare catalyst-doped WO ₃ thin films on the surface of glass slides or polished silicon wafers, and the pulling speed is 4-6.5cm/min;

Or: ②Use the spin coating method to prepare catalyst-doped WO ₃ film on the surface of silicon wafer or K9 glass, the pre-coating rate is 900-1100r/min, and the spin-coating rate is 2500-3500r/min;

Baking the obtained catalyst-doped WO ₃ film in an air atmosphere at a temperature of 50°C-250°C for 50-70 minutes;

The film prepared by this method has good cycle performance, and there is still no obvious attenuation after 500 cycles.

Embodiment 4: Preparation of two-phase mixed doping WO3/ _SiO2 film preparation

(1) Preparation of WO ₃ sol:

Using the sol-gel method, under normal temperature and pressure, tungsten powder and hydrogen peroxide solution were stirred and reacted for 50-70 minutes, the molar ratio of tungsten powder and hydrogen peroxide was 1:3-1:4, centrifuged and filtered to obtain Light yellow transparent solution; then add absolute ethanol to the resulting solution, the amount of absolute ethanol added is 1/2 to 4/5 of the volume of the container, and reflux in an oil bath at 75-85°C for 1.5-2 hours until the sol is transformed into Orange yellow, namely to obtain WO ₃ ethanol sol.

(2) Preparation of Si sol

Use a volumetric flask and a pipette to accurately measure orthoethyl silicate (TEOS) or methyltriethoxysilane and alcohol, the ratio is: 77.8/100; seal the mouth of beaker A with a cleaning film and a rubber band Place it on a magnetic stirrer for stirring, and the stirring time is half an hour;

(3) Preparation of WO ₃ and SiO ₂ composite sol

Add step (2) gained sol in the sol of step (1) gained, the ratio of this kind of sol is adjusted according to the thickness of required film and the depth of coloring, and this dispersion ratio suggests adopting WO3/ _SiO Molar ratio is 1/ 1

(4) WO3/SiO _sol of doping catalyst Preparation:

Add catalyst to the sol obtained in step (3), stir at normal temperature for 2 to 3 hours, when the sol is a reddish-brown stable sol, store it under normal pressure and zero temperature for subsequent use; the molar ratio of catalyst to tungsten powder is 1: 40～1:100, the catalyst is K ₂ [PtCl ₄ ] or PdCl ₂ ;

(5) Preparation of catalyst-doped WO ₃ film: prepared by pulling dipping method or spin coating method:

①Use the pulling and immersion plating method to prepare catalyst-doped WO ₃ thin films on the surface of glass slides or polished silicon wafers, and the pulling speed is 4-6.5cm/min;

Or: ②Use the spin coating method to prepare catalyst-doped WO ₃ film on the surface of silicon wafer or K9 glass, the pre-coating rate is 900-1100r/min, and the spin-coating rate is 2500-3500r/min;

Baking the obtained catalyst-doped WO ₃ film in an air atmosphere at a temperature of 50°C-250°C for 50-70 minutes;

The film prepared by this method has good cycle performance, and there is still no obvious attenuation after 500 cycles.

Example 5: Preparation of two-phase mixed doped WO3/Al ₂ O ₃ film preparation

(1) Preparation of WO ₃ sol:

Using the sol-gel method, under normal temperature and pressure, tungsten powder and hydrogen peroxide solution were stirred and reacted for 50-70 minutes, the molar ratio of tungsten powder and hydrogen peroxide was 1:3-1:4, centrifuged and filtered to obtain Light yellow transparent solution; then add absolute ethanol to the resulting solution, the amount of absolute ethanol added is 1/2 to 4/5 of the volume of the container, and reflux in an oil bath at 75-85°C for 1.5-2 hours until the sol is transformed into Orange yellow, namely to obtain WO ₃ ethanol sol.

(2) Preparation of Al ₂ O ₃ sol

Volumetric flask and pipette respectively accurately measure anhydrous aluminum chloride + deionized water + ethanol + propylene oxide (6mmol: 0.65ml: 6-40ml: 0.32ml); or aluminum isopropoxide + water + isopropanol + Catalyst (acid or alkali, take hydrochloric acid as an example), the ratio is 1mmol: 3mmol: 1-10ml: 0.1mmol; accurately measure the required sol into the beaker; seal the mouth of the beaker with a cleaning film and a rubber band Finally, it was placed on a magnetic stirrer for stirring for 4 hours; aging at 50°C for 1 hour.

(3) Preparation of WO ₃ and Al ₂ O ₃ composite sol

Add the sol obtained in step (2) to the sol obtained in step (1), and the ratio of this sol is adjusted according to the thickness and color depth of the required film. This dispersion ratio is recommended to adopt WO3/ _SiO The molar ratio is 1.25/ 1

(4) Preparation of catalyst-doped WO3/Al ₂ O ₃ sol:

Add catalyst to the sol obtained in step (3), stir at normal temperature for 2 to 3 hours, when the sol is a reddish-brown stable sol, store it under normal pressure and zero temperature for subsequent use; the molar ratio of catalyst to tungsten powder is 1: 40～1:100, the catalyst is K ₂ [PtCl ₄ ] or PdCl ₂ ;

(5) Preparation of catalyst-doped WO ₃ film: prepared by pulling dipping method or spin coating method:

①Use the pulling and immersion plating method to prepare catalyst-doped WO ₃ thin films on the surface of glass slides or polished silicon wafers, and the pulling speed is 4-6.5cm/min;

Or: ②Use the spin coating method to prepare catalyst-doped WO ₃ film on the surface of silicon wafer or K9 glass, the pre-coating rate is 900-1100r/min, and the spin-coating rate is 2500-3500r/min;

Baking the obtained catalyst-doped WO ₃ film in an air atmosphere at a temperature of 50°C-250°C for 50-70 minutes;

The film prepared by this method has good cycle performance, and there is still no obvious attenuation after 500 cycles.

Example 6: Preparation of two-phase mixed doped WO3/Al ₂ O ₃ thin film

(1) Preparation of WO ₃ sol:

Using the sol-gel method, under normal temperature and pressure, tungsten powder and hydrogen peroxide solution were stirred and reacted for 50-70 minutes, the molar ratio of tungsten powder and hydrogen peroxide was 1:3-1:4, centrifuged and filtered to obtain Light yellow transparent solution; then add absolute ethanol to the resulting solution, the amount of absolute ethanol added is 1/2 to 4/5 of the volume of the container, and reflux in an oil bath at 75-85°C for 1.5-2 hours until the sol is transformed into Orange yellow, namely to obtain WO ₃ ethanol sol.

(2) WO3/ _SiO sol of doping catalyst Preparation:

Add catalyst to the sol obtained in step (1), stir at normal temperature for 2 to 3 hours, when the sol is a reddish-brown stable sol, store it under normal pressure and zero temperature for subsequent use; the molar ratio of catalyst to tungsten powder is 1: 40～1:100, the catalyst is K ₂ [PtCl ₄ ] or PdCl ₂ ;

(3) Composite film preparation of WO ₃ sol and Al ₂ O ₃ template

Soak the 70nm Al ₂ O ₃ template in the sol prepared in (2), and vibrate in ultrasonic for 30 minutes; take out the Al ₂ O ₃ template, and place the obtained catalyst-doped WO ₃ thin film in the air atmosphere, and bake the glue at a temperature of 50°C-250°C, the time is 50-70 minutes;

The film prepared by this method has good cycle performance, and there is still no obvious attenuation after 500 cycles.

The present invention should use solidification and dispersion technology to reduce the agglomeration of WO ₃ and improve the porosity of WO ₃ aerochromic film by using additive materials to realize the cycle life of the aerochromic film. The stable WO ₃ composite sol was prepared by the Sol-gel method; a transparent and uniform composite WO ₃ porous film doped with catalyst was plated on ordinary glass by the pulling method or the spin coating method. This curing dispersion technology improves and strengthens the pore structure of the film, reduces the interaction between WO ₃ , and improves the cycle life and thermal stability of the aerochromic film prepared by the sol-gel technology. Compared with the untreated film, the aerochromic thin film prepared by doping and compounding the sol of the present invention greatly improves the cycle of aerochromic color; compared with the aerochromic thin film prepared by magnetron sputtering, etc. The performance is the same, and the cost will be significantly lower; compared with the electrochromic film, it also has the same advantages. The invention well makes up for the shortcomings of the aerochromic smart windows prepared by the sol-gel method, and makes the technology of such smart windows more mature.

The above description of the embodiments is for those of ordinary skill in the art to understand and apply the present invention. It is obvious that those skilled in the art can easily make various modifications to these embodiments, and apply the general principles described here to other embodiments without creative effort. Therefore, the present invention is not limited to the embodiments herein, and improvements and modifications made by those skilled in the art according to the disclosure of the present invention should fall within the protection scope of the present invention.

Claims (5)

1. A method for improving WO ₃ film gas-induced cycle performance, characterized in that: adopting WO ₃ The inorganic matter that can improve the porosity of the aerochromic thin film is doped to WO ₃ sol, and said inorganic matter includes SiO ₂ , Al ₂ O ₃ ; The method comprises the steps of: (1) preparation of WO ₃ sol; (2) Selection and preparation of SiO ₂ and Al ₂ O ₃ sols; (3) Preparation of WO ₃ and SiO ₂ , Al ₂ O ₃ composite sol: (4) Preparation of catalyst-doped WO ₃ /SiO ₂ , WO ₃ /Al ₂ O ₃ sols: (5) Preparation of catalyst-doped WO ₃ /SiO ₂ , WO ₃ /Al ₂ O ₃ films; The preparation of the WO ₃ sol: Using the sol-gel method, under normal temperature and pressure, tungsten powder and hydrogen peroxide solution were stirred and reacted for 50-70 minutes, the molar ratio of tungsten powder and hydrogen peroxide was 1:3-1:4, centrifuged and filtered to obtain Light yellow transparent solution; then add absolute ethanol to the resulting solution, the amount of absolute ethanol added is 1/2 to 4/5 of the volume of the container, and reflux in an oil bath at 75-85°C for 1.5-2 hours until the sol is transformed into Orange yellow, that is, to obtain WO ₃ ethanol sol; The preparation of the SiO ₂ and Al ₂ O ₃ sols: including: ① Preparation of acidic SiO ₂ sol: Use a volumetric flask and a pipette to accurately measure deionized water, absolute ethanol, and tetraethyl orthosilicate as the silicon source. The ratio can be adjusted appropriately according to the experimental temperature, type of silicon source, and test time. Deionized water at room temperature The proportion of tetraethyl orthosilicate is: 23.5/77.8; the acid is accurately weighed according to the amount of deionized water taken to prepare an acid solution with pH<7, pour it into beaker A, and put a clean magnetic stirring bar into beaker A; then accurately measure the required amount of tetraethyl orthosilicate and the required amount of absolute ethanol into beaker A in turn; seal the mouth of beaker A with a cleaning film and rubber band and place it in a magnetic stirrer Stir on, according to the acidic _SiO prepared according to the above ratio The sol stirring time is 2-4 hours and just can make the acidic SiO _sol ; Or ② Preparation of Alkaline SiO ₂ Sol: The raw materials and proportions required for the preparation of _SiO2 sol by alkaline catalysis, the molar ratio is as follows: tetraethyl orthosilicate (TEOS): ethanol: ammonia water = 1/38/2.45, the preparation process of the sol should be in a clean, relative humidity Carry out under the environment of being less than 60%, the steps are as follows: use volumetric flask and pipette to accurately measure the dehydrated alcohol of required amount 1/2 and pour in beaker A; Use pipette to accurately measure required amount of pH= Pour 12% concentrated ammonia water into beaker A; put a clean magnetic stirrer into beaker A, seal the mouth of beaker A with a cleaning film and rubber band, place it on a magnetic stirrer and stir for about 20 minutes to achieve uniform dispersion Purpose; Use a volumetric flask and a pipette to accurately measure the required tetraethyl orthosilicate and 1/2 of the required amount of absolute ethanol and pour them into beaker B in sequence; put a clean magnetic stirring bar into beaker B, and use a clean Seal the mouth of beaker B with a film and rubber band, place it on a magnetic stirrer and stir for about 20 minutes to achieve uniform dispersion; use a magnet to take out the magnetic stirrer in beaker A along the outer wall, and pour the mixed solution in beaker A into the pear-shaped separating funnel; slowly drop the mixed solution in the pear-shaped separating funnel into the beaker B placed on the magnetic stirrer, while keeping stirring evenly; It is mixed evenly, and then the stirring bar in the beaker B is taken out along the outer wall with a magnet; Seal the beaker B with a clean film and a rubber band and let it stand in a stable environment: 16-24°C, relative humidity <50% for aging. The aged sol is in the form of light blue latex. At this time, the particles in the sol The average particle size is less than 10nm. Take out the sol and pour it into a round bottom flask. The sol must not be immersed in more than 2/3 of the flask; add a small amount of clean molecular sieve to the round bottom flask to prevent bumping, and then fix the flask with an iron stand Silicone oil in a water bath heating pot; adjust the temperature of the oil bath between 80°C and 85°C to keep the sol liquid surface in a slightly boiling state; use a serpentine reflux tube for reflux, and use the wetted quantitative pH test paper at the mouth of the reflux tube Carry out the test until the pH test paper has no change, stop heating, take out the flask after natural cooling; pour the sol into a beaker and seal it for storage; Or ③ preparation of other SiO ₂ sols: Use methyltriethoxysilane silicon source and alcohol to mix according to the required ratio to form a sol with corresponding concentration; Or ④ Preparation of Al ₂ O ₃ sol: Volumetric flasks and pipettes were used to accurately measure anhydrous aluminum chloride + deionized water + ethanol + propylene oxide, or aluminum isopropoxide + water + isopropanol + catalyst; pour the required sol into In a beaker; seal the mouth of the beaker with a cleaning film and a rubber band and place it on a magnetic stirrer for stirring for 4 hours; aging at 50°C for 1 hour; Preparation of the WO ₃ and SiO ₂ , Al ₂ O ₃ composite sol: Add the sol obtained in step (2) to the sol obtained in step (1), the dispersion ratio: SiO ₂ : WO ₃ molar ratio ≥ 1/1 or Al ₂ O ₃ : WO ₃ molar ratio: 1/1; Preparation of the catalyst-doped WO ₃ /SiO ₂ , WO ₃ /Al ₂ O ₃ sols: Add catalyst to the sol obtained in step (3), stir at normal temperature for 2 to 3 hours, when the sol is a reddish-brown stable sol, store it under normal pressure and zero temperature for subsequent use; the molar ratio of catalyst to tungsten powder is 1: 40 to 1:100, the catalyst is K ₂ [PtCl ₄ ] or PdCl ₂ . 2. The method according to claim 1, characterized in that: the catalyst-doped WO ₃ /SiO ₂ , WO ₃ /Al ₂ O ₃ thin films are prepared by pulling and dipping or spin coating: ①Prepare catalyst-doped WO ₃ /SiO ₂ , WO ₃ /Al ₂ O ₃ thin films on the surface of glass slides or polished silicon wafers by pulling dip-plating method, the pulling speed is 4-6.5cm/min; Or: ②Use the spin coating method to prepare catalyst-doped WO ₃ /SiO ₂ , WO ₃ /Al ₂ O ₃ thin films on the surface of silicon wafers or K9 glass. The pre-coating rate is 900-1100r/min, and the spin-coating rate is 2500- 3500r/min; The obtained catalyst-doped WO ₃ /SiO ₂ and WO ₃ /Al ₂ O ₃ films are baked in an air atmosphere at a temperature of 50°C-250°C for 50-70 minutes. 3. The method according to claim 1, characterized in that: in order to obtain a thicker film, adopt the method of improving _WO sol concentration or pulling speed, the higher the concentration, the faster the pulling speed and the thicker the film; or adopt In the method of multiple spin coatings, the film is heat-treated at a temperature of 40-55° C. for 2-5 minutes between each spin coating. 4. The method according to claim 1, characterized in that: the catalyst in the preparation of the acidic _SiO sol is one of hydrochloric acid, tungstic acid, nitric acid, phosphoric acid, oxalic acid, and the pH=2 is adjusted. 5. The method according to claim 1, characterized in that: in the preparation of the _Al2O3 sol, the ratio of anhydrous aluminum chloride+deionized water+ethanol+propylene oxide is 6mmol: 0.65ml _: 6 - 40ml: 0.32ml; or the ratio of aluminum isopropoxide + water + isopropanol + hydrochloric acid is 1mmol: 3mmol: 1-10ml: 0.1mmol.

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