阅读说明：本技术 一种电化学沉积法制备氧化钨电致变色薄膜的方法 (Method for preparing tungsten oxide electrochromic film by electrochemical deposition method ) 是由 姚爱华 貌俊达 耿磊 于 2019-08-28 设计创作，主要内容包括：本发明涉及一种电化学沉积法制备氧化钨电致变色薄膜的方法。本发明的目的是要解决现有的水溶液体系下氧化钨电致变色薄膜的调制范围窄、薄膜寿命短以及制备方法复杂所导致的不适合大规模生产的技术问题。本发明：一、清洗导电玻璃基片；二、配置电沉积溶液；三、电化学法沉积薄膜；四、薄膜电沉积后处理。本发明的有益效果：1、本发明所使用的电沉积方法和条件简单,可以作为大规模生产的方法；2、本发明所获得的氧化钨的电致变色调制范围广,寿命好,脱色态下的薄膜在可见光范围内有很高的透过率,可供实际电致变色玻璃器件使用；3、本发明方法不需要大型的仪器和贵重药品,操作方法简单,成本低廉,便于实施,可应用于大规模工业生产。(The invention relates to a method for preparing a tungsten oxide electrochromic film by an electrochemical deposition method. The invention aims to solve the technical problems that the tungsten oxide electrochromic film in the existing aqueous solution system is narrow in modulation range, short in service life and complex in preparation method, and is not suitable for large-scale production. The invention comprises the following steps: firstly, cleaning a conductive glass substrate; secondly, preparing an electrodeposition solution; thirdly, depositing a film by an electrochemical method; and fourthly, performing post-treatment of film electrodeposition. The invention has the beneficial effects that: 1. the electro-deposition method and conditions used by the invention are simple and can be used as a method for large-scale production; 2. the tungsten oxide obtained by the invention has wide electrochromic modulation range and long service life, and the thin film in a decolored state has high transmittance in a visible light range, so that the tungsten oxide can be used for an actual electrochromic glass device; 3. the method of the invention does not need large-scale instruments and expensive medicines, has simple operation method, low cost and convenient implementation, and can be applied to large-scale industrial production.)

1. A method for preparing a tungsten oxide electrochromic film by an electrochemical deposition method is characterized in that the preparation method of the tungsten oxide electrochromic film is carried out according to the following steps:

the method comprises the following steps: cleaning the conductive glass substrate: ultrasonically cleaning a conductive glass substrate for 5-15 minutes by using acetone, absolute ethyl alcohol and deionized water in sequence, and drying to obtain a clean conductive glass substrate; the conductive glass substrate is an ITO substrate or an FTO glass substrate.

Step two: and preparing an electrodeposition solution for later use.

Step three: and (3) depositing a film by an electrochemical method: and (3) using the solution obtained in the step two as an electrodeposition solution, using the conductive glass substrate obtained in the step one as a working electrode, using a platinum sheet or a titanium-platinum sheet as a counter electrode, using an Ag/AgCl electrode as a reference electrode, and depositing a tungsten oxide film on the conductive glass substrate by a constant potential method.

Step four: film treatment: and taking the conductive glass deposited with the film out of the electrodeposition solution, immediately washing with deionized water, and then drying the moisture on the surface of the glass to obtain the tungsten oxide electrochromic film.

2. The method for preparing the tungsten oxide electrochromic film by the electrochemical deposition method according to claim 1, wherein the preparation of the electrodeposition solution in the second step comprises the following steps:

weighing tungsten powder (analytically pure) with a certain mass, putting the tungsten powder into a container, and adding a hydrogen peroxide solution (30% by mass fraction) according to the following proportion: the mass of tungsten powder per 1L of hydrogen peroxide solution was 229.8 g. The two reactants are placed at room temperature for reaction, and stirring is carried out simultaneously in the reaction process.

② when the solution after reaction is cooled to room temperature, inserting platinum sheet to catalyze and decompose unreacted hydrogen peroxide. And taking out the platinum sheet and stopping the reaction when the volume of the solution V2(ml) after the reaction/the volume of the hydrogen peroxide solution V1(ml) added in the first step is 0.75-0.85.

Preparing a mixed solution of water and isopropanol (Vwater: Visopropanol: 7:3), adding the mixed solution into the solution obtained in the step (2), and diluting to 25 times of the original volume.

Stirring the solution diluted in the previous step for 12-50h until the solution presents uniform and transparent yellow.

3. The method for preparing the tungsten oxide electric transformation film by the electrochemical deposition method according to claim 1, wherein the constant potential deposition potential adopted in the third step is-0.4V to-5V.

4. The method for preparing the tungsten oxide electric transformation film by the electrochemical deposition method according to claim 1, wherein the deposition time of the constant potential deposition adopted in the step three is 20-60 min.

5. The method for preparing the tungsten oxide electric transformation film by the electrochemical deposition method according to claim 1, wherein the moisture on the surface of the glass is removed by using warm air flow in the fourth step.

Technical Field

The invention relates to a preparation method of an electrochromic film, in particular to a method for preparing a tungsten oxide electrochromic film by an electrochemical deposition method.

Background

The electrochromic material refers to a material of which the optical properties (such as transmittance, reflectivity, absorptivity and the like) can generate stable reversible change under the action of an applied electric field, and the material is shown in appearance as reversible change between the color and the transparency of the material. The electrochromic material has the advantages of good memory function, low driving voltage, low energy consumption, rich colors, intelligence, controllability and the like, and has wide application prospect in the fields of intelligent glass, automatic anti-glare rearview mirrors, information displays and the like. The intelligent color-changing glass can regulate and control heat exchange through a window by regulating the light transmittance under a lower voltage (2-5V), so that the purpose of energy saving is achieved, and the effects of improving the natural illumination degree and preventing peeping are achieved. For example, the windows of Germany BMW and Audi cars are provided with electrochromic glass, and the glass not only has the characteristics of all safety glass, but also has the privacy protection function of controlling the transparency of the glass. The glass after changing color not only can effectively shelter from sunlight to protect the interior trim plastic part of the automobile, but also can play the purposes of cooling and reducing the temperature in the automobile body, and has great benefit on the comfort during driving. In addition, the field test of products of Asachi Glass company, Gesimat company and Sage Glass company in Japan is respectively carried out by Lorentsback national laboratory in America, and the result shows that the application of the electrochromic Glass can save 75% of electricity for the lighting peak of a commercial building and 25% of electricity for the air conditioning peak, thereby greatly reducing the energy consumption of the building. The automatic anti-dazzling rearview mirror prepared from the electrochromic material can adjust the intensity of reflected light according to the intensity of external light through an electronic induction system, so that the anti-dazzling effect is achieved, and driving is safer.

At present, the application bottlenecks of the oxide electrochromic material are that the color change response is slow, the contrast is low, and the phenomenon that the electrochromic performance of the film is degraded in the use process. Moreover, most of the electrochromic films on the market are prepared by a magnetron sputtering method, and the coating method has high equipment cost and needs a high-vacuum environment, so that the later-period running cost is also quite high. The invention provides a method for preparing a large-area tungsten oxide electrochromic film by an electrochemical deposition method, which has the advantages of relatively low equipment cost, no need of a vacuum device, greatly simplified production process and higher production efficiency, and thus, the production cost can be greatly reduced.

Chinese patents CN109336195A and CN109437241A propose methods for preparing tungsten oxide films by electrodeposition, however, their methods require first preparing polystyrene microsphere templates on glass substrates, then electrodepositing tungsten oxide films, and finally removing the templates to obtain glass with porous structure. It is clear that this method is only suitable for laboratory performance and is not suitable for large-scale production. Compared with the method disclosed by the invention, the method disclosed by the invention can be used for obtaining the large-area nickel oxide film with good electrochromic performance without preparing a template on the substrate in advance.

Disclosure of Invention

The invention aims to provide a preparation method for preparing an electrochromic tungsten oxide film by an electrodeposition method, which is simple in process, aiming at the technical problems of narrow optical modulation range, slow color change response, short cycle life and high production cost of the film prepared by the existing tungsten oxide electrochromic film method.

The method for preparing the tungsten oxide electrochromic film by the electrochemical deposition method is carried out according to the following steps:

firstly, cleaning a conductive glass substrate: ultrasonically cleaning a conductive glass substrate for 5-10 minutes by using acetone, absolute ethyl alcohol and deionized water in sequence, and drying or blow-drying to obtain a clean conductive glass substrate; the conductive glass substrate is an ITO substrate or an FTO glass substrate.

Secondly, preparing an electrodeposition solution:

(1) weighing tungsten powder (analytically pure) with a certain mass, putting the tungsten powder into a container, and adding a hydrogen peroxide solution (30% by mass fraction) according to the following proportion: the mass of tungsten powder per 1L of hydrogen peroxide solution was 229.8 g. The two reactants are placed at room temperature for reaction, and stirring is carried out simultaneously in the reaction process.

(2) And when the solution after reaction is cooled to room temperature, inserting a platinum sheet to catalyze and decompose unreacted hydrogen peroxide. Volume V of solution after reaction₂(ml)/volume V of hydrogen peroxide solution added in the first step₁When the amount of (ml) is 0.75 to 0.85, the platinum sheet is taken out and the reaction is stopped.

(3) Preparing a mixed solution (V) of water and isopropanol_{Water (W)}：V_{Isopropanol (I-propanol)}7:3), adding the mixture into the solution obtained in the step (2), and diluting the mixture until the original body is obtained25 times the product.

(4) And stirring the solution diluted in the previous step for 12-50h until the solution is uniform and transparent yellow.

Thirdly, depositing a film by an electrochemical method: and (3) taking the solution obtained in the step two as an electrodeposition solution, taking the conductive glass substrate obtained in the step one as a working electrode, taking a platinum sheet or a titanium-platinum sheet as a counter electrode, taking an Ag/AgCl electrode as a reference electrode, and keeping the distance between the working electrode and the counter electrode to be 1.5-3 cm. The constant potential deposition time is 20-60 min; the deposition potential is-0.4V to-5V.

Fourthly, film post-treatment: and taking the conductive glass deposited with the film out of the electrodeposition liquid, immediately washing with deionized water, and blow-drying the surface moisture of the glass by using normal-temperature airflow to obtain the tungsten oxide electrochromic film.

Compared with the prior art, the tungsten oxide electrochromic film prepared by the method has the following advantages:

1. the invention adopts the electrochemical deposition method to prepare the tungsten oxide electrochromic film, and compared with the magnetron sputtering method, the cost is low and the operation is simple; compared with a sol-gel method, the preparation process is simpler and controllable, and large-scale production is easy to realize.

2. The tungsten oxide electrochromic film prepared by the electrochemical deposition method has the characteristics of wide optical modulation range (delta T is more than 85%), short fading response time (<15s) and long cycle life (the number of fading/developing cycles in propylene carbonate solution of lithium perchlorate is more than 8000).

3. The electrochemical deposition method adopted by the invention can prepare the large-area tungsten oxide electrochromic film.

Drawings

FIG. 1 is a graph showing transmittance curves of glass after 1 and 8000 cycles of development/fading of a tungsten oxide electrochromic film having an area of 5cm × 5cm prepared in example 1 of the present invention, which shows that the optical modulation range of the film is wide.

Fig. 2 is an optical photograph of the electrochromic film of tungsten oxide prepared in example 1 of the present invention in a discolored state and a developed state.

Fig. 3 shows the response time of the light transmittance at wavelength λ of 633nm after 1 and 8000 cycles of developing/decoloring of the tungsten oxide electrochromic film prepared in example 1 according to the present invention, which illustrates that the response time of developing and decoloring of the film is short.

Fig. 4 is a cyclic voltammetry curve of the tungsten oxide electrochromic film prepared in example 1 of the present invention after 1 and 8000 development/decolorization cycles, which shows that the film has no performance degradation and long cycle life after 8000 cycles.

FIG. 5 is an optical photograph of an electrochromic film of tungsten oxide having an area of 10cm by 10cm prepared in example 2 of the present invention in a bleached state and a developed state.

Detailed Description

The present invention will be described in detail with reference to the following examples and drawings, but the present invention is not limited thereto.

Example 1

Firstly, cleaning a conductive glass substrate: and (3) sequentially ultrasonically cleaning an ITO conductive glass substrate (the square resistance is 7-10 omega) with the area of 5m multiplied by 5cm by acetone, absolute ethyl alcohol and deionized water for 10min, and drying at 50 ℃ to obtain the clean conductive glass substrate.

Secondly, preparing an electrodeposition solution:

5.745g of tungsten powder (analytically pure) is weighed and placed in a container.

Measuring 25ml of hydrogen peroxide solution (30 mass percent), adding the hydrogen peroxide solution into a container containing tungsten powder, reacting at room temperature, and stirring simultaneously in the reaction process.

And thirdly, when the solution after reaction is cooled to room temperature, inserting a platinum sheet to catalyze and decompose unreacted hydrogen peroxide, and stirring simultaneously in the reaction process. And when the volume of the solution after the reaction is 20ml, taking out the platinum sheet and stopping the reaction.

And fourthly, 336ml of deionized water and 144ml of isopropanol are added into the solution after the reaction in the previous step for dilution, and finally 500ml of solution is obtained.

Fifthly, stirring the diluted solution for 35 hours to obtain uniform and transparent yellow solution.

Thirdly, depositing a film by an electrochemical method: and (3) taking the solution obtained in the step two as an electrodeposition solution, taking the ITO conductive glass substrate obtained in the step one as a working electrode, taking a platinum sheet with the area of 5cm multiplied by 5cm as a counter electrode, taking an Ag/AgCl electrode as a reference electrode, keeping the distance between the working electrode and the counter electrode at 1.5cm, setting the deposition potential to be-0.5V, taking out the ITO glass deposited with the tungsten oxide film after constant potential deposition for 20min, and immediately cleaning the ITO glass with deionized water. Fourthly, film post-treatment: and drying the moisture on the surface of the glass by using a hair drier with the power of 1000W to obtain the tungsten oxide electrochromic film.

Electrochromic properties of the tungsten oxide electrochromic film prepared in example 1 were tested: (1) dissolving lithium perchlorate in propylene carbonate to prepare 1mol/L solution; (2) the ITO glass deposited with the tungsten oxide film is used as a working electrode, a platinum sheet is used as a counter electrode, an Ag/AgCl electrode is used as a reference electrode, and voltages of-0.5V and 0.5V are applied to find that the tungsten oxide film reversibly changes between transparency and blue, and the change of the transmittance of the film between 350-850nm wave bands is detected after 8000 times of development and fading cycles, wherein the results are shown in Table 1 and figure 1; the electrochromic response speed of the film was measured as the response change of light transmittance at wavelength λ 633nm, and the result is shown in fig. 2; the current-voltage curve was measured after 1 cycle of 8000 cycles, and the change in the properties was evaluated, and the results are shown in FIG. 3.

TABLE 1 comparison of performance of tungsten oxide electrochromic films prepared in example 1 after 1 and 8000 development/bleaching cycles

Table 1 shows the transmittance, transmittance change rate in developed and faded state, and development and fading time of the tungsten oxide electrochromic film prepared in example 1 of the present invention after 1 and 8000 development/fading cycles, which indicates that the film has no performance degradation and long cycle life after 8000 development/fading cycles.

Example 2

Firstly, cleaning a conductive glass substrate: and (2) sequentially ultrasonically cleaning an ITO conductive glass substrate (the square resistance is 7-10 omega) with the area of 10m multiplied by 10cm by acetone, absolute ethyl alcohol and deionized water for 10 minutes, and drying at 50 ℃ to obtain the clean conductive glass substrate.

Secondly, preparing an electrodeposition solution:

11.49g of tungsten powder (analytically pure) is weighed and placed in a container.

Measuring 50ml of hydrogen peroxide solution (30 mass percent), adding the hydrogen peroxide solution into a container containing tungsten powder, and reacting at room temperature.

And thirdly, when the solution after reaction is cooled to room temperature, inserting a platinum sheet to catalyze and decompose unreacted hydrogen peroxide, and stirring simultaneously in the reaction process. When the volume of the solution after the reaction was 40ml, the platinum sheet was taken out and the reaction was stopped.

And fourthly, 672ml of deionized water and 288ml of isopropanol are added into the solution after the reaction in the previous step for dilution, and finally 1000ml of solution is obtained.

Fifthly, stirring the diluted solution for 48 hours to obtain uniform and transparent yellow solution.

Thirdly, depositing a film by an electrochemical method: and (3) taking the solution obtained in the step two as an electrodeposition solution, taking the ITO conductive glass substrate obtained in the step one as a working electrode, taking a titanium platinum sheet with the area of 14cm multiplied by 14cm as a counter electrode, taking an Ag/AgCl electrode as a reference electrode, keeping the distance between the working electrode and the counter electrode at 2.5cm, setting the deposition potential to be-0.7V, taking out the ITO glass deposited with the tungsten oxide film after constant potential deposition for 30min, and immediately cleaning the ITO glass with deionized water.

Fourthly, film post-treatment: drying the moisture on the surface of the film by using a hair drier with the power of 1200W to obtain the oxide electrochromic film with the area of 10cm multiplied by 10 cm.

Optical photographs of the tungsten oxide electrochromic film prepared in example 2 in the color-developed state and the color-faded state are shown in fig. 5. The optical modulation range of the film is tested as follows: delta T is more than 85 percent, the developing time is 10.3, the decoloring time is 9.6s, and the developing/decoloring cycle number in the propylene carbonate solution of lithium perchlorate is more than 8000.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.