A super-large variable emission and transmittance laminated electrochromic device and its preparation method

Abstract

The present invention discloses an ultra-large emission, high-transmittance, high-gap stacked electrochromic device and its preparation method. The present invention uses ammonium metatungstate and polyvinyl pyrrolidone as structural morphology directing agents to grow WO3 thin films, and optimizes film performance by stacking WO3 and V2O5. Experimental results show that the change in emissivity in the front hemisphere between the fading state and the colored state of the film prepared by this patent can reach 0.4650, the change in normal emissivity is equal to 0.4660, and the visible transmittance change ∆T lum Equal to 39.50%, thermal regulation capacity ∆T sol The device can reach 26.55%. It has a wide color change range. When used in aerospace thermal control, it can adjust the spacecraft's outer surface's thermophysical properties, such as hemispherical emissivity and transmittance, through electrical signals, thereby controlling the spacecraft's surface thermal balance. The device also has broad application prospects in displays, smart windows, light modulators, sensors, smart glasses, and variable infrared / near-infrared devices.

Description

Technical Field

[0001] The present invention relates to an ultra-large variable emission and transmittance stacked electrochromic device and a preparation method thereof, belonging to the field of new materials. Background Art

[0002] Electrochromic materials are materials that undergo reversible and dramatic changes in transmittance or emissivity through the insertion and extraction of ions in the presence of an applied electric and ionic field. Common electrochromic materials include WO3, V2O5, TiO2, Ta2O5, RuO2, MoO3, MnO2, CuO, NiO, MoO3, conductive polymers (polyaniline, polythiophene, polypyrrole), organic single molecules (violet essence), Prussian blue, and metal-organic frameworks. Although electrochromic displays based on organic molecules, polymers, and metal-organic frameworks exhibit a variety of color characteristics, these materials lack the thermal and chemical stability of their inorganic electrochromic counterparts, which has seriously hindered their commercial application.

[0003] Inorganic electrochromic displays are considered to be at the forefront of commercial electrochromic display technology. V2O5 and WO3 can achieve yellow-green-gray-black and transparent-blue transitions, respectively, during electrochromic changes. Therefore, they have a wide range of applications in electrochromic films, gas sensors, supercapacitors, and electrochemical devices. V2O5's layered crystal structure can accommodate the insertion and removal of lithium ions, but strain can lead to structural disintegration and interlayer delamination. Furthermore, V2O5's relatively low lithium ion diffusion coefficient and moderate conductivity limit the rapid diffusion of ions, resulting in a sluggish switching response in the device.

[0004] There are many methods for preparing WO3 and V2O5 thin films. The sol-gel method has attracted widespread attention due to its low equipment cost, ease of scalable production, and commercial application. V2O5 can be melted at 850°C to prepare a sol. However, the melting point of tungsten oxide (1473°C) is higher than that of vanadium pentoxide (690°C), making it difficult to prepare a precursor sol by melting the oxide at high temperatures. Currently, three common sol-gel methods for preparing WO3 precursor sols include wet chemical methods, where tungsten or tungsten carbide powder reacts with hydrogen peroxide to produce a peroxytungstic acid sol; inorganic sol methods, where WCl6 is dissolved in an alcohol solution; and the synthesis of a tungsten oxide sol by reacting tungstic acid with sodium tungstate dihydrate. The present invention utilizes a method for preparing a high-concentration WO3 precursor sol by dissolving ammonium metatungstate in water. Although nitrogen and carbon impurities are introduced into the sol, these elements evaporate as NH3 and CO2 during subsequent high-temperature annealing of the film. The prepared tungsten oxide film has a higher gap, which is conducive to the contact between ions and the FTO conductive substrate, showing higher charge density and higher transmittance optical performance. Summary of the Invention

[0005] To address the poor electrochemical performance of V2O5, this invention proposes a novel WO3 / V2O5 stacked electrochromic device with ultra-large variable emission and transmittance, as well as a preparation method. The tungsten and vanadium sources are derived from ammonium metatungstate and vanadium pentoxide, resolving the shortcomings of existing technologies.

[0006] The invention is implemented as follows:

[0007] A super-large variable emission and transmittance laminated electrochromic device, characterized in that the device includes FTO glass sheets at both ends, and between the two FTO glass sheets are sequentially provided: a single-sided conductive copper tape, glass beads, UV light-cured adhesive, a gel electrolyte, a single-sided conductive copper tape, a V2O5 film, and a WO3 film; a layer of single-sided conductive copper tape is fixed at the edge of the conductive surface of the FTO glass sheet; the FTO glass sheet and the single-sided conductive copper tape serve as the conductive layer of the device; the V2O5 film and the WO3 film serve as the laminated electrochromic layer of the device; the glass beads, UV light-cured adhesive, and gel electrolyte serve as the ion storage layer of the device; a fern-shaped high-gap WO3 film is generated on the surface of the FTO glass immersed in an ammonium metatungstate precursor sol by a constant temperature film pulling machine, and then a layer of V2O5 film is deposited to form a WO3 / V2O5 laminated film. Ammonium metatungstate and polyvinyl pyrrolidone (or other structure-directing agents such as polyethylene glycol) are used to prepare WO3 precursor sol, and then a WO3 and V2O5 stacking scheme is used to optimize the film properties.

[0008] The method for preparing a high-gap laminated electrochromic device with ultra-large variable emissivity and transmittance of the present invention is characterized in that the preparation method comprises:

[0009] Step 1: Ultrasonic clean two 5.0cm*5.0cm FTO glass sheets with alcohol and acetone for half an hour respectively. After drying, fix a 7.0cm long single-sided conductive copper tape on the edge of the conductive surface of the glass sheet. Connect the extra length of single-sided conductive copper tape to the positive and negative terminals of the electrochemical workstation. Flatten the single-sided conductive copper tape and set aside for use.

[0010] Step 2: Weigh 34g of ammonium metatungstate or ammonium tungstate into 80ml of distilled water and stir at room temperature for 1 hour to obtain ammonium metatungstate or ammonium tungstate precursor sol, add an appropriate amount of structure directing agent with a mass fraction of 20%, stir evenly, and stop stirring to obtain tungsten oxide precursor sol; then use a film pulling machine to pull the FTO glass sheet cleaned in step 1 to grow a layer of WO3 precursor film;

[0011] Step 3: placing the stacked WO3 precursor film deposited in step 2 into a muffle furnace and annealing at 650° C. for 3 hours to obtain a thin film electrochromic film;

[0012] Step 4: Weigh 4 grams of V2O5 powder and put it into a crucible. Place the crucible in a muffle furnace and heat it to 850°C. After keeping warm for half an hour, quickly pour the molten V2O5 into 200 ml of distilled water. Stir for half an hour to form a V2O5 sol. Then centrifuge it to filter out the undissolved V2O5, and pour the V2O5 sol into a beaker. Then, a layer of V2O5 precursor film is deposited on the FTO glass sheet on which WO3 is deposited in step 2 through a film pulling machine. The parameters of the film pulling machine are the same as those in step 2. The centrifuge parameters are set to: 3500 rpm, 2 hours.

[0013] Step 5: Place the laminated film deposited in step 4 in a muffle furnace and anneal at 300° C. for 3 hours; change the film thickness by changing the number of pull-ups;

[0014] Step 6: Mix 20 ml of 1.0 mol / L battery-grade 100 vol% lithium perchlorate propylene carbonate electrolyte with 5 g of polymethyl methacrylate (PMMA) at 80°C under a nitrogen or argon atmosphere. The resulting viscous gel electrolyte is ready for use.

[0015] Step 7: Place 4 100μm glass beads around the conductive surface of the laminated WO3 / V2O5 film annealed in step 4, and then apply an appropriate amount of gel electrolyte prepared in step 6 on the laminated surface; as the outermost layer, slowly place the FTO glass sheet on top of the gel electrolyte from the edge; after removing the bubbles in the middle of the glass sheet, seal it with an appropriate amount of UV light curing glue on all sides, and place it under a purple lamp for 10 minutes to obtain a high-gap WO3 / V2O5 laminated electrochromic device.

[0016] Furthermore, the structure directing agent is a mixture of one or more of polyvinyl alcohol, citric acid, dodecylbenzenesulfonic acid, ethylenediaminetetraacetic acid, and polyvinylpyrrolidone (PVP-K30); the molecular weight of the polyvinylpyrrolidone is 10,000-100,000.

[0017] Furthermore, the parameters of the film pulling machine are set as follows: pulling speed is 200 μm / s, pulling times is 10 times, pulling interval is 13 minutes, dwell interval is 30 seconds, and temperature is room temperature.

[0018] The beneficial effect of adopting the above technical solution is that although the use of ammonium metatungstate and structure-directing agents introduces N and C element impurities, after subsequent annealing, the N and C elements will escape as NH3 and CO2, and the prepared WO3 film will have a higher gap. The high-gap WO3 film is beneficial to the contact between ions and the FTO conductive substrate, showing a higher charge density, with sensitive coloring efficiency and good electrochromic stability. The improved sol-gel method has low equipment cost, mild and safe reaction, simple preparation process and short cycle. The crystallinity of the tungsten oxide film can be controlled by controlling the annealing temperature to improve the electron transport efficiency. Experimental results show that the change in hemispherical emissivity between the faded state and the colored state of the film can reach 0.4650, the change in normal emissivity is equal to 0.4660, and the visible transmittance change ∆T lum Equal to 39.50%, thermal regulation capacity ∆T sol The device can reach 26.55%. When used in aerospace thermal control, it can adjust the spacecraft's outer surface's thermophysical properties, such as hemispherical emissivity and transmittance, through electrical signals, thereby controlling the spacecraft's surface thermal balance. The device also has broad application prospects in displays, smart windows, light modulators, sensors, smart glasses, and variable infrared / near-infrared devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 SEM photograph of the surface morphology of the film prepared in Example 1 after annealing at 650°C;

[0020] Figure 2 Spectral transmittance curves of Example 3 and related prepared coating samples at 200nm to 2500nm;

[0021] Figure 3 Schematic diagram of the preparation process of the WO3 / V2O5 laminated electrochromic film of the present invention;

[0022] Figure 4 Schematic diagram of the structure of the WO3 / V2O5 stacked electrochromic device of the present invention;

[0023] Among them, 1-FTO glass sheet, 2-single-sided conductive copper tape, 3-glass microbeads, 4-UV light curing glue, 5-gel electrolyte, 6-V2O5 film, 7-WO3 film. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and effect of the present invention clearer and more specific, the following examples are given to further illustrate the present invention in detail. It should be noted that the specific implementation described here is only used to explain the present invention and is not intended to limit the present invention.

[0025] The preparation method of the present invention is as follows:

[0026] (1) Ultrasonic cleaning of the FTO glass slide with alcohol and acetone for half an hour respectively. After drying, a layer of 7.0 cm long single-sided conductive copper tape is fixed on the edge of the conductive surface of the glass slide (the extra length of the single-sided conductive copper tape is for connecting the positive and negative terminals of the electrochemical workstation). The single-sided conductive copper tape is flattened and set aside for use.

[0027] (2) Weigh 34g of ammonium metatungstate (or ammonium tungstate) and pour it into 80ml of distilled water. Stir at room temperature for 1 hour to obtain ammonium metatungstate (or ammonium tungstate) precursor sol. Pour an appropriate amount of structure-directing agent (a mixture of one or more of polyvinyl alcohol, citric acid, dodecylbenzenesulfonic acid, ethylenediaminetetraacetic acid, and polyvinyl pyrrolidone) with a mass fraction of 20%, stir evenly, and stop stirring. Obtain tungsten oxide precursor sol. Then, use a film pulling machine (pulling speed of 200μm / s, pulling times of 10 times, pulling interval of 13 minutes, dwell interval of 30 seconds, and temperature of room temperature) to pull and grow a layer of WO3 precursor film on the FTO glass sheet cleaned in step (1).

[0028] (3) The laminated WO3 precursor film deposited in step 2 was placed in a muffle furnace and annealed at 650°C for 3 hours to obtain a thin film electrochromic film. The micromorphology of the film is shown in FIG. Figure 1 As shown in the figure, the transmission spectrum curves of WO3 and WO3 / V2O5 stacks in bleached and colored states with different pulling times are shown in the figure. Figure 2 shown.

[0029] (4) Weigh 4 g of V2O5 powder and place it in a crucible. Place the crucible in a muffle furnace and heat it to 850°C. After keeping the temperature for half an hour, quickly pour the molten V2O5 into 200 ml of distilled water. Stir for half an hour to form a V2O5 sol. Centrifuge the crucible (3500 rpm, 2 hours) to filter out the undissolved V2O5. Pour the V2O5 sol into a beaker. Then, deposit a layer of V2O5 precursor film on the FTO glass sheet with WO3 deposited in step 2 through a film drawing machine. The film drawing machine settings are the same as those in step 2.

[0030] (5) Place the laminated film deposited in step 4 in a muffle furnace and anneal at 300°C for 3 hours. The transmission spectrum curves of the bleached state and the colored state with different pulling times are shown in Fig. Figure 2 The preparation process diagram is shown in Figure 3 .

[0031] (6) Mix a certain amount of 1.0 mol / L battery-grade 100 vol% lithium perchlorate propylene carbonate electrolyte with a certain amount of PMMA and stir them at 80°C under a nitrogen (or argon) atmosphere until uniform. A viscous gel electrolyte is obtained and removed for later use.

[0032] (7) Figure 2As shown, four 100μm glass beads are placed around the conductive surface of the laminated WO3 / V2O5 film after annealing in step 4, and then an appropriate amount of gel electrolyte prepared in step 6 is coated on the laminated surface. As the outermost layer, a FTO glass sheet is slowly placed on top of the gel electrolyte from the edge. After removing the bubbles in the middle of the glass sheet, an appropriate amount of UV light curing glue is used to seal the surrounding area. Place it under a purple light for 10 minutes. A high-gap WO3 / V2O5 laminated electrochromic device is obtained. The schematic diagram of the structure of the WO3 / V2O5 laminated electrochromic device is shown in Figure 4 As shown, it includes FTO glass sheets 1 at both ends, and between the two FTO glass sheets 1 are sequentially: single-sided conductive copper tape 2, glass beads 3, UV light curing glue 4, gel electrolyte 5, single-sided conductive copper tape 2, V2O5 film 6, and WO3 film 7.

[0033] The present invention is described below with reference to specific examples.

[0034] Example 1

[0035] (1) Ultrasonic cleaning of the FTO glass slide with alcohol and acetone for half an hour respectively. After drying, a layer of 7.0 cm long single-sided conductive copper tape is fixed on the edge of the conductive surface of the glass slide (the extra length of the single-sided conductive copper tape is for connecting the positive and negative terminals of the electrochemical workstation). The single-sided conductive copper tape is flattened and set aside for use.

[0036] (2) Weigh 34g of ammonium metatungstate (or ammonium tungstate) and pour it into 80ml of distilled water. Stir at room temperature for 1 hour to obtain ammonium metatungstate (or ammonium tungstate) precursor sol. Pour an appropriate amount of polyvinyl pyrrolidone structure directing agent with a mass fraction of 20%, stir evenly, and stop stirring. Obtain tungsten oxide precursor sol. Then, use a film pulling machine (pulling speed of 50μm / s, pulling number of times of 5 times, pulling interval of 13 minutes, dwell interval of 30 seconds, temperature of room temperature) to pull and grow a layer of WO3 precursor film on the FTO glass sheet cleaned in step (1).

[0037] (3) The WO3 precursor film deposited in step 2 was placed in a muffle furnace and annealed at 650°C for 3 hours to obtain a WO3 electrochromic thin film.

[0038] (4) Weigh 4 g of V2O5 powder and place it in a crucible. Place the crucible in a muffle furnace and heat it to 850°C. After keeping the temperature for half an hour, quickly pour the molten V2O5 into 200 ml of distilled water. Stir for half an hour to form a V2O5 sol. Centrifuge the crucible (3500 rpm, 2 hours). After filtering out the undissolved V2O5, pour the V2O5 sol into a beaker. Then, deposit a layer of V2O5 precursor film on the FTO glass sheet with WO3 deposited in step 2 through a film pulling machine. The film pulling machine is set to a pulling speed of 50 μm / s, a pulling number of 5 times, a pulling interval of 13 minutes, a dwell interval of 30 seconds, and a temperature of room temperature.

[0039] (5) The laminated film deposited in step 4 is placed in a muffle furnace and annealed at 300° C. for 3 hours to obtain a laminated electrochromic film.

[0040] (6) Mix 20 ml of 1.0 mol / L battery-grade 100 vol% lithium perchlorate in propylene carbonate with 5 g of PMMA and stir at 80°C under a nitrogen (or argon) atmosphere until uniform. A viscous gel electrolyte is obtained and is ready for use.

[0041] (7) Figure 2 As shown, four 100μm glass beads are placed around the conductive surface of the laminated WO3 / V2O5 film after annealing in step 4, and then an appropriate amount of gel electrolyte prepared in step 5 is coated on the laminated surface. As the outermost layer, an FTO glass sheet is slowly placed on top of the gel electrolyte from the edge. After removing the bubbles in the middle of the glass sheet, an appropriate amount of UV light curing glue is used to seal the surrounding area. Place it under a purple light for 10 minutes. A high-gap WO3 / V2O5 laminated electrochromic device 1 is obtained. At 10V, the hemispherical emissivity of device 1 changes from 0.2240 to 0.6670 before and after power is applied, and the normal emissivity changes from 0.2370 to 0.6930. The change in hemispherical emissivity is 0.4430. The change in normal emissivity is 0.456.

[0042] The surface morphology SEM photos of the film prepared in Example 1 after annealing at 650°C are as follows: Figure 1 After annealing, WO3 forms a fern-like leaf-like structure with a high gap on the glass surface, which is beneficial for increasing the contact area between electrons and the stacked electrochromic layer, showing a higher charge density and having sensitive and excellent coloring efficiency.

[0043] Example 2

[0044] (1) Ultrasonic cleaning of the FTO glass slide with alcohol and acetone for half an hour respectively. After drying, a layer of 7.0 cm long single-sided conductive copper tape is fixed on the edge of the conductive surface of the glass slide (the extra length of the single-sided conductive copper tape is for connecting the positive and negative terminals of the electrochemical workstation). The single-sided conductive copper tape is flattened and set aside for use.

[0045] (2) Weigh 34g of ammonium metatungstate (or ammonium tungstate) and pour it into 80ml of distilled water. Stir at room temperature for 1 hour to obtain ammonium metatungstate (or ammonium tungstate) precursor sol. Pour an appropriate amount of polyvinyl pyrrolidone structure directing agent with a mass fraction of 20%, stir evenly, and stop stirring. Obtain tungsten oxide precursor sol. Then, use a film pulling machine (pulling speed of 50μm / s, pulling number of times of 10 times, pulling interval of 13 minutes, dwell interval of 30 seconds, temperature at room temperature) to pull and grow a layer of WO3 precursor film on the FTO glass sheet cleaned in step (1).

[0046] (3) The WO3 precursor film deposited in step 2 was placed in a muffle furnace and annealed at 650°C for 3 hours to obtain a WO3 electrochromic thin film.

[0047] (4) Weigh 4 g of V2O5 powder and place it in a crucible. Place the crucible in a muffle furnace and heat it to 850°C. After keeping the temperature for half an hour, quickly pour the molten V2O5 into 200 ml of distilled water. Stir for half an hour to form a V2O5 sol. Centrifuge the crucible (3500 rpm, 2 hours). After filtering out the undissolved V2O5, pour the V2O5 sol into a beaker. Then, deposit a layer of V2O5 precursor film on the FTO glass sheet with WO3 deposited in step 2 through a film pulling machine. The film pulling machine is set to a pulling speed of 50 μm / s, 10 pulling times, a pulling interval of 13 minutes, a dwell interval of 30 seconds, and room temperature.

[0048] (5) The laminated film deposited in step 4 was placed in a muffle furnace and annealed at 300°C for 3 hours to obtain a laminated electrochromic film. The microscopic morphology is shown in FIG. Figure 1 ,

[0049] (6) Mix 20 ml of 1.0 mol / L battery-grade 100 vol% lithium perchlorate in propylene carbonate with 5 g of PMMA and stir at 80°C under a nitrogen (or argon) atmosphere until uniform. A viscous gel electrolyte is obtained and is ready for use.

[0050] (7) Figure 2 As shown, four 100μm glass beads are placed around the conductive surface of the laminated WO3 / V2O5 film after annealing in step 4, and then an appropriate amount of gel electrolyte prepared in step 5 is coated on the laminated surface. As the outermost layer, an FTO glass sheet is slowly placed on top of the gel electrolyte from the edge. After removing the bubbles in the middle of the glass sheet, an appropriate amount of UV light curing glue is used to seal the surrounding area. Place it under a purple light for 10 minutes. A high-gap WO3 / V2O5 laminated electrochromic device 2 is obtained. At a voltage of 10V, the hemispherical emissivity of device 2 changes from 0.2840 to 0.7490 before and after power is applied, and the normal emissivity changes from 0.2920 to 0.7580. The change in hemispherical emissivity is 0.4650. The change in normal emissivity is 0.4660.

[0051] Example 3

[0052] (1) Ultrasonic cleaning of the FTO glass slide with alcohol and acetone for half an hour respectively. After drying, a layer of 7.0 cm long single-sided conductive copper tape is fixed on the edge of the conductive surface of the glass slide (the extra length of the single-sided conductive copper tape is for connecting the positive and negative terminals of the electrochemical workstation). The single-sided conductive copper tape is flattened and set aside for use.

[0053] (2) Weigh 68g of ammonium metatungstate (or ammonium tungstate) and pour it into 80ml of distilled water. Stir at room temperature for 1 hour to obtain an ammonium metatungstate (or ammonium tungstate) precursor sol. Pour an appropriate amount of polyvinyl pyrrolidone structure directing agent with a mass fraction of 20%, stir evenly, and stop stirring. Obtain a tungsten oxide precursor sol. Then, use a film pulling machine (pulling speed of 50μm / s, pulling number of times of 10 times, pulling interval of 13 minutes, dwell interval of 30 seconds, temperature at room temperature) to pull and grow a layer of WO3 precursor film on the FTO glass sheet cleaned in step (1).

[0054] (3) The stacked WO3 precursor film deposited in step 2 was placed in a muffle furnace and annealed at 650°C for 3 hours to obtain a WO3 electrochromic thin film.

[0055] (4) Weigh 4 g of V2O5 powder and place it in a crucible. Place the crucible in a muffle furnace and heat it to 850°C. After keeping the temperature for half an hour, quickly pour the molten V2O5 into 200 ml of distilled water. Stir for half an hour to form a V2O5 sol. Centrifuge the crucible (3500 rpm, 2 hours). After filtering out the undissolved V2O5, pour the V2O5 sol into a beaker. Then, deposit a layer of V2O5 precursor film on the FTO glass sheet with WO3 deposited in step 2 through a film pulling machine. The film pulling machine is set to a pulling speed of 50 μm / s, 10 pulling times, a pulling interval of 13 minutes, a dwell interval of 30 seconds, and room temperature.

[0056] (5) The laminated film deposited in step 4 is placed in a muffle furnace and annealed at 300° C. for 3 hours to obtain a laminated electrochromic film.

[0057] (6) Mix 20 ml of 1.0 mol / L battery-grade 100 vol% lithium perchlorate in propylene carbonate with 5 g of PMMA and stir at 80°C under a nitrogen (or argon) atmosphere until uniform. A viscous gel electrolyte is obtained and is ready for use.

[0058] (7) Place four 100μm glass beads around the conductive surface of the laminated WO3 / V2O5 film after annealing in step 4, and then apply an appropriate amount of gel electrolyte prepared in step 5 on the laminated surface. As the outermost layer, slowly place the FTO glass sheet on top of the gel electrolyte from the edge. After removing the bubbles in the middle of the glass sheet, seal it with an appropriate amount of UV light curing glue on all sides. Place it under a purple light for 10 minutes. A high-gap WO3 / V2O5 laminated electrochromic device 3 is obtained. Under a voltage of 10V, the hemispherical emissivity of device 3 changes from 0.5250 to 0.790 before and after power is applied, and the normal emissivity changes from 0.5550 to 0.8260. The change in hemispherical emissivity is 0.2650. The change in normal emissivity is 0.2710. The visible transmittance change ∆T lum Equal to 39.50%. Thermal regulation capacity ∆Tsol It is 26.55%.

[0059] The spectral reflectance curves of the coating samples prepared in Example 3 and related preparations at 200nm to 2500nm are as follows: Figure 2 As shown in the figure. The light gray area in the figure represents the solar radiation spectrum when the sun is at an angle of 37 degrees to the horizon and the atmosphere is at an atmospheric mass of 1.5, while the dark gray area represents the human visual function curve. The figure shows that the transmission spectrum curves of the WO3 / V2O5 stack in the bleached and colored states vary significantly. The transmittance difference at 600nm can reach 42.58%, indicating a transmittance change of ∆T. lum Equal to 39.50%. Thermal regulation capacity ∆T sol It is 26.55%.

[0060] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements can be made without departing from the principles of the present invention. These improvements should also be regarded as the scope of protection of the present invention.

Claims

1. A variable emissivity and transmittance stacked electrochromic device, characterized in that: The device comprises an FTO glass sheet (1) at both ends, and the two FTO glass sheets (1) sequentially comprise: a single-sided conductive copper tape (2), glass microbeads (3), UV light curing glue (4), a gel electrolyte (5), a single-sided conductive copper tape (2), a V2O5 film (6), and a WO3 film (7); a layer of single-sided conductive copper tape (2) is fixed at the edge of the conductive surface of the FTO glass sheet (1); the FTO glass sheet (1) and the single-sided conductive copper tape (2) serve as the conductive layer of the device; the V2O5 film (6) and the WO3 film (7) serve as the laminated electrochromic layer of the device; the glass microbeads (3), UV light curing glue (4), and the gel electrolyte (5) serve as the ion storage layer of the device; a high-gap WO3 film in the shape of a fern leaf is formed on the surface of the FTO glass immersed in an ammonium metatungstate precursor sol by a constant temperature film pulling machine, and then a layer of V2O5 film is deposited to form a WO3 / V2O5 laminated film.

2. A method for preparing a variable emissivity and transmittance stacked electrochromic device according to claim 1, characterized in that: The preparation method is: Step 1: Ultrasonic clean two 5.0cm*5.0cm FTO glass sheets with alcohol and acetone for half an hour respectively. After drying, fix a 7.0cm long single-sided conductive copper tape on the edge of the conductive surface of the glass sheet. Connect the extra length of single-sided conductive copper tape to the positive and negative terminals of the electrochemical workstation. Flatten the single-sided conductive copper tape and set aside for use. Step 2: Weigh 34g of ammonium metatungstate or ammonium tungstate into 80ml of distilled water and stir at room temperature for 1 hour to obtain ammonium metatungstate or ammonium tungstate precursor sol, add an appropriate amount of structure directing agent with a mass fraction of 20%, stir evenly, and stop stirring to obtain tungsten oxide precursor sol; then use a film pulling machine to pull the FTO glass sheet cleaned in step 1 to grow a layer of WO3 precursor film; Step 3: placing the stacked WO3 precursor film deposited in step 2 into a muffle furnace and annealing at 650° C. for 3 hours to obtain an electrochromic thin film; Step 4: Weigh 4 grams of V2O5 powder and put it into a crucible. Place the crucible in a muffle furnace and heat it to 850°C. After keeping warm for half an hour, quickly pour the molten V2O5 into 200 ml of distilled water. Stir for half an hour to form a V2O5 sol. Then, centrifuge it to filter out the undissolved V2O5, and pour the V2O5 sol into a beaker. Then, the FTO glass sheet with the WO3 thin film deposited in step 2 is passed through a film pulling machine to deposit another layer of V2O5 precursor film. The centrifuge parameters are set to: 3500 rpm, 2 hours; Step 5: Place the laminated film deposited in step 4 in a muffle furnace and anneal at 300° C. for 3 hours; change the film thickness by changing the number of pull-ups; Step 6: Take 20 ml of 1.0 mol / L battery-grade 100 Vol% lithium perchlorate propylene carbonate electrolyte and mix it with 5 g of polymethyl methacrylate under nitrogen or argon atmosphere at 80° C. and stir until evenly mixed to obtain a viscous gel electrolyte, which is then taken out for use; Step 7: Place 4 100μm glass beads around the conductive surface of the laminated WO3 / V2O5 film annealed in step 4, and then apply an appropriate amount of gel electrolyte prepared in step 6 on the laminated surface; as the outermost layer, slowly place the FTO glass sheet on top of the gel electrolyte from the edge; after removing the bubbles in the middle of the glass sheet, seal it with an appropriate amount of UV light curing glue on all sides, and place it under a purple lamp for 10 minutes to obtain a high-gap WO3 / V2O5 laminated electrochromic device.

3. The method for preparing a variable emissivity and transmittance stacked electrochromic device according to claim 2, characterized in that: The structure directing agent is a mixture of one or more of polyvinyl alcohol, citric acid, dodecylbenzenesulfonic acid, ethylenediaminetetraacetic acid, and polyvinyl pyrrolidone; the molecular weight of the polyvinyl pyrrolidone is 10,000-100,000.

4. The method for preparing a variable emissivity and transmittance stacked electrochromic device according to claim 2, characterized in that: The parameters of the film pulling machine are set as follows: pulling speed is 200 μm / s, pulling times is 10 times, pulling interval is 13 minutes, dwell interval is 30 seconds, and temperature is room temperature.

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