High-stability sedimentary electrochromic device as well as preparation method and application thereof
By using C3N4-CNT electrodes and phenyltrimethylammonium bromide material in deposition-type electrochromic devices, the Br-/Br3- conversion was improved, the self-fading problem was solved, the cycle performance and color retention were enhanced, energy consumption was reduced, the preparation process was simplified, and the stability was improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-02-25
- Publication Date
- 2026-04-10
AI Technical Summary
Existing deposition-type electrochromic devices have shortcomings in terms of cycle performance and color maintenance, and are prone to self-fading, resulting in increased energy consumption and poor stability.
A highly stable electrochromic device was fabricated using a C3N4-CNT electrode and phenyltrimethylammonium bromide material. By improving the conversion of Br-/Br3- at the electrode and suppressing the self-diffusion of Br3-, a Cu2+-free electrolyte was used, combined with a spin-coating process.
It improves the device's cycle performance and color retention, reduces energy consumption, simplifies the fabrication process, and enhances the device's stability and ability to retain the transparent state.
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Figure CN121832167A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of electrochromic devices, in particular to a high-stability deposition type electrochromic device and a preparation method and application thereof. BACKGROUND
[0002] The active materials commonly used in the dynamic window of the deposition type electrochromic technology are metal silver (Ag), copper (Cu), bismuth (Bi), zinc (Zn) and the like, and the metal ions in the electrolyte are deposited on the transparent electrode by electrochemical deposition to realize the reversible color switching between the transparent state and the dark state. Compared with the traditional electrochromic material, the metal deposition type electrochromic technology generally produces a higher extinction coefficient and a higher optical contrast. Secondly, the deposition and dissolution of the metal make the structure simpler than the ion intercalation / deintercalation device, thereby significantly reducing the manufacturing and material costs of the device.
[0003] However, the devices in the current research generally have the problems of Cu 2+ and Br3 - , wherein the addition of Cu 2+ helps to help the dissolution after silver deposition, and can have good cycle performance, but the initial color of the electrolyte is yellow after adding Cu 2+ , and the colorless transparent state cannot be completely maintained. Secondly, Br - in the electrolyte can form a complex with silver to improve the solubility in the electrolyte and the effect of charge compensation reaction at the counter electrode. However, in the reaction process, Br - will become Br3 - , and when the concentration of Br3 - becomes large, it will spontaneously diffuse to the working electrode and corrode the deposited silver film. This will cause the phenomenon of self-fading, and the color retention effect is poor, and if the color state is to be maintained, a regular voltage needs to be constantly applied, resulting in a large energy consumption. There are still obvious shortcomings in the application of the deposition type electrochromic technology, and the device is prone to self-fading, which directly leads to weak cycle performance and poor color maintenance, which becomes a key problem restricting the further landing of the technology. SUMMARY
[0004] The purpose of the present application is to provide a high-stability deposition type electrochromic device and a preparation method and application thereof, which solves the problems in the background art.
[0005] To achieve the above-mentioned purpose, the present application provides a preparation method of a high-stability deposition type electrochromic device, comprising the following steps: S1, triazine and carbon nanotubes are added to an organic solvent and ultrasonically treated, heated and stirred, then filtered, washed and dried to obtain a powder for standby use; S2, the powder obtained in S1 is placed at the bottom of a quartz boat, the first ITO glass is covered on the top of the quartz boat, the cover of the quartz boat is placed on the first ITO glass, the entire quartz boat is wrapped with tin paper, and the quartz boat is placed in a tube furnace for heating reaction; after cooling to room temperature, the C3N4-CNT electrode is obtained; S3, the Nafion solution, the organic solvent and the phenyltrimethylammonium bromide are mixed to obtain a mixed solution after ultrasonic treatment; S4, the C3N4-CNT electrode in S2 is placed in a glue spreading machine, the mixed solution in S3 is dropped on the C3N4-CNT electrode, and the C3N4-CNT-PTMAB electrode is obtained after heating after spin coating; S5, one side of the silica gel pad is adhered to the second ITO glass, and the C3N4-CNT-PTMAB electrode in S4 is adhered to the other side of the silica gel pad, and the sandwich structure device is obtained after pressing; S6, the silica gel pad of the sandwich structure device in S5 has a notch gap, and the silver-containing electrolyte is injected into the notch gap, and the deposition type electrochromic device is obtained after sealing.
[0006] Preferably, the mass ratio of melamine to carbon nanotube is 3:0.01-0.05.
[0007] Preferably, in S2, the conductive side of the first ITO glass is covered on the top of the quartz boat.
[0008] Preferably, in S2, the heating atmosphere is air atmosphere, the heating temperature is 500-600℃, the heating rate is 1-5℃ / min, and the heating time is 1-5h.
[0009] Preferably, in S4, the spin coating speed is 1500-2500r / min, the spin coating time is 10-30s, the heating temperature is 50-70℃, and the heating time is 1-5h.
[0010] Preferably, in S5, the shape of the silica gel pad is the same as that of the second ITO glass, and the side of the silica gel pad is provided with a notch gap.
[0011] Preferably, in S6, the silver-containing electrolyte comprises one or more of silver nitrate, tetrabutylammonium bromide, citric acid and polyvinylpyrrolidone.
[0012] Preferably, the first ITO glass and the second ITO glass are cleaned before use, and are sequentially soaked in cleaning agent, water and anhydrous ethanol for ultrasonic treatment for 30min, and are blown dry and treated with ultraviolet ozone.
[0013] The above-mentioned preparation method of the deposition type electrochromic device with high stability can prepare the deposition type electrochromic device.
[0014] The aforementioned highly stable deposition-type electrochromic device is applied in smart windows, low-power displays, and wearable color-changing devices.
[0015] Therefore, the present invention employs the above-mentioned highly stable deposition-type electrochromic device, its preparation method, and its application, and its beneficial effects are as follows: 1. This invention improves the performance of the counter electrode Br by preparing a C3N4-CNT electrode. - / Br3 - The conversion improves cycle performance, and the spin-coating of phenyltrimethylammonium bromide material promptly adsorbs excess Br3 generated in the electrolyte during the reaction. - Avoid Br3 - Self-diffusion to the working electrode leads to self-fading phenomenon; 2. The electrolyte provided by this invention does not use Cu. 2+ The key factors that cause the initial coloration are directly eliminated at the core component level. Secondly, as a transmission-type deposition-type electrochromic device, the C3N4-CNT electrode itself is colorless and transparent, which further ensures that the initial state of the entire device is not affected from the structural level. 3. The preparation method provided by the present invention has the characteristics of strong cycle performance, simple preparation process and convenient operation, and has good application prospects.
[0016] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description
[0017] Figure 1 This is a schematic diagram of the structure of a highly stable deposition-type electrochromic device according to the present invention; Figure 2 This is a diagram showing the combination of the deposition-type electrochromic device under different voltages in an embodiment of the present invention, wherein... Figure 2 (a) in the figure is the transmittance curve in the wavelength range of 400-800nm; Figure 2 (b) in the figure shows the color change of the deposition-type electrochromic device; Figure 3 This is a cyclic current-voltage curve of the deposition-type electrochromic device in an embodiment of the present invention; Figure 4 This is a transmittance response diagram of the deposition-type electrochromic device at 550 nm during cyclic voltammetry testing in an embodiment of the present invention. Figure 5 This is a performance comparison diagram of the embodiments and comparative examples in this invention; wherein, Figure 5 (a) in the figure is a comparison of the fading response curves at a voltage of 0.7V; Figure 5 (b) in the figure is the transmittance cycle stability test curve at a wavelength of 550 nm; Figure 6 This is a color retention transmittance response curve of the deposition-type electrochromic device at a wavelength of 550nm after coloring, as shown in the embodiment of the present invention. Figure 7 This is a coloring efficiency diagram of the deposition-type electrochromic device in an embodiment of the present invention; Figure 8 This is a coloring and fading time diagram of the deposition-type electrochromic device in an embodiment of the present invention. Detailed Implementation
[0018] The present invention will be further described below with reference to the accompanying drawings and embodiments. Unless otherwise defined, the technical or scientific terms used in this invention should be understood in their ordinary sense by those skilled in the art. The features mentioned above or in the specific examples mentioned in this invention can be combined arbitrarily, and these specific embodiments are only used to illustrate the invention and are not intended to limit the scope of the invention.
[0019] like Figure 1 As shown, this invention provides a method for fabricating a highly stable deposition-type electrochromic device, comprising the following steps: S1. Melamine and carbon nanotubes are added to an organic solvent and ultrasonically treated. After heating and stirring, the mixture is filtered, washed, and dried to obtain a powder for later use. Ultrasonic treatment ensures that melamine and carbon nanotubes are uniformly dispersed in methanol to prevent agglomeration. Heating and reflux promotes the interaction between melamine and the surface of carbon nanotubes (CNTs), forming a preliminary composite.
[0020] S2. Place the powder obtained in S1 into the bottom of the quartz boat, cover the top of the quartz boat with the first ITO glass, place the lid of the quartz boat on the first ITO glass, wrap the entire quartz boat with tin foil, place it in a tube furnace for heating and reaction, and remove it after cooling to room temperature to obtain the C3N4-CNT electrode; during the heating process, melamine is thermally polymerized to generate g-C3N4, and CNTs are embedded in the C3N4 structure. At the same time, the generated C3N4-CNTs are directly deposited on the conductive surface of the ITO glass, enhancing adhesion and electrical contact.
[0021] S3. Mix Nafion solution, organic solvent, and phenyltrimethylammonium bromide, and sonicate to obtain a mixed solution; the quaternary ammonium salt structure of phenyltrimethylammonium bromide can electrostatically adsorb Br3 in the electrolyte. - This inhibits its diffusion into the second ITO glass of the working electrode.
[0022] S4. Place the C3N4-CNT electrode from S2 into a spin coater. Drop the mixed solution from S3 onto the C3N4-CNT electrode. Spin coat and heat to obtain a C3N4-CNT-PTMAB electrode. Use centrifugal force to spread the mixed solution evenly. Heat to remove the organic solvent, allowing phenyltrimethylammonium bromide and Nafion solution to form a uniform Br3 mixture on the surface of the C3N4-CNT electrode. - Adsorption layer, to obtain C3N4-CNT-PTMAB electrode.
[0023] S5. Attach one side of the silicone pad to the second ITO glass, and attach the C3N4-CNT-PTMAB electrode from S4 to the other side of the silicone pad, pressing them together to obtain a sandwich structure device. The thickness of the silicone pad is the thickness of the electrolyte chamber and defines the size of the colored area. The second ITO glass serves as the working electrode, where silver is deposited / dissolved. The C3N4-CNT-PTMAB electrode serves as the counter electrode, combining catalytic and adsorption functions.
[0024] In S6 and S5, the silicone pads of the sandwich structure devices have gaps. Silver-containing electrolyte is injected into the gaps and then sealed to obtain a deposition-type electrochromic device.
[0025] In some embodiments of the present invention, the mass ratio of melamine to carbon nanotubes is 3:0.01-0.05. Melamine pyrolysis produces graphitic carbon nitride g-C3N4, which has catalytic activity and can promote Br… - / Br3 - Conversion. Carbon nanotubes provide a highly conductive network, enhancing electrode conductivity and promoting electron transfer.
[0026] In some embodiments of the present invention, in S2, the conductive side of the first ITO glass is covered on the top of the quartz boat.
[0027] In some embodiments of the present invention, in step S2, the heating atmosphere is air, the heating temperature is 500-600°C, the heating rate is 1-5°C / min, and the heating time is 1-5 hours. Controlling the heating rate and slowly increasing the temperature is beneficial for forming uniform and well-crystallized C3N4.
[0028] In some embodiments of the present invention, in step S4, the spin coating speed is 1500-2500 r / min, the spin coating time is 10-30 s, the heating temperature is 50-70℃, and the heating time is 1-5 h.
[0029] In some embodiments of the present invention, in S5, the shape of the silicone pad is the same as the shape of the second ITO glass, and the side of the silicone pad is provided with a notch or gap.
[0030] In some embodiments of the present invention, in step S6, the silver-containing electrolyte includes one or more of silver nitrate, tetrabutylammonium bromide, citric acid, and polyvinylpyrrolidone. Silver nitrate provides Ag... + For deposition, excess Br - Citric acid and polyvinylpyrrolidone (PVP) are used to form soluble complexes and to stabilize the system.
[0031] In some embodiments of the present invention, the first ITO glass and the second ITO glass are cleaned before use, and are then immersed in cleaning agent, water and anhydrous ethanol in sequence and sonicated for 30 minutes, dried and then treated with ultraviolet ozone.
[0032] Example S1. Before use, clean the first and second ITO glass, immerse them sequentially in cleaning agent, water, and anhydrous ethanol, and sonicate for 30 minutes. After drying, treat with ultraviolet ozone. Add 3g of melamine and 3g of carbon nanotubes with a mass concentration of 0.69wt% to 80mL of methanol and sonicate for 1 hour. Then, heat in an oil bath at 60℃ and stir under reflux for 2 hours. After filtration, wash three times with deionized water and anhydrous ethanol, and dry at 60℃ for 1-2 days to obtain powder. Then, grind the dried powder and collect it for later use.
[0033] S2. Place 0.25g of the powder obtained in S1 into the bottom of the quartz boat, cover the top of the quartz boat with the conductive side of the first ITO glass, then place the lid of the quartz boat on the first ITO glass, and wrap the entire quartz boat with tin foil. Place it in a tube furnace and heat the reaction in an air atmosphere at a temperature of 550℃, a heating rate of 3℃ / min, and a heating time of 3h. After cooling to room temperature, remove the C3N4-CNT electrode.
[0034] S3. Mix 20 μl Nafion solution, 980 μl anhydrous ethanol and 0.02 g phenyltrimethylammonium bromide, and sonicate for 1 h to obtain a mixed solution.
[0035] S4. Place the C3N4-CNT electrode from S2 into a spin coater, drop the mixed solution from S3 onto the C3N4-CNT electrode, spin coat at a speed of 2000 r / min for 20 s, heat at 60 ℃ for 2 h, and heat to remove the solvent after spin coat to obtain the C3N4-CNT-PTMAB electrode.
[0036] S5. The silicone pad has the same shape as the second ITO glass, with a central effective area of 2×2cm. 2A 1mm thick double-sided adhesive silicone pad has notches and gaps on its side. One side of the double-sided adhesive silicone pad is attached to the second ITO glass, and the C3N4-CNT-PTMAB electrode in S4 is attached to the other side of the double-sided adhesive silicone pad as the counter electrode. The two are then pressed together to obtain a sandwich structure device.
[0037] In S6, 10 mmol / L silver nitrate, 50 mmol / L tetrabutylammonium bromide, 20 mmol / L citric acid, and 20 mmol / L polyvinylpyrrolidone were added to 20 ml of dimethyl sulfoxide and stirred for 1 h to obtain a silver-containing electrolyte. In S5, the silicone gasket of the sandwich structure device had gaps; the silver-containing electrolyte was injected into these gaps, and the gaps and edges were sealed with silicone rubber to obtain a deposition-type electrochromic device.
[0038] Comparative Example The difference between this comparative example and the embodiment is that steps S1-S4 are not performed. In step S5, one side of the silicone pad is attached to the second ITO glass, and the first ITO glass is attached to the other side of the silicone pad. The two are then pressed together to obtain a sandwich structure device. The remaining steps in the uniform embodiment are the same to obtain an electrochromic device.
[0039] Test case In electrochemical testing, a two-step voltage method is used to achieve color change in the device. A reverse voltage is then applied to achieve fading. The first step, the nucleation voltage, involves a relatively high voltage applied for a short duration to form uniformly dispersed silver nuclei. This voltage ranges from -3V to -4V and lasts for 0.05-0.1s. The second step, the growth voltage, is the main stage of color change and the process of continuous silver nuclei growth. This voltage ranges from -1.5V to -2.5V, and the duration can vary from 1 to 20s depending on the specific color change.
[0040] The transmittance of the device under different voltages was measured using an electrochemical workstation and a UV-Vis spectrophotometer. The transmittance of the device in different wavelength ranges was measured using the UV-Vis spectrophotometer, and the cycling performance and color retention performance were evaluated based on the transmittance response at 550 nm.
[0041] like Figure 2 As shown, Figure 2 Figure (a) shows the transmittance curves of the deposited electrochromic device in the 400-800 nm wavelength range under different voltage conditions. With increasing deposition time, the surface plasmon resonance absorption peak generated by the silver nanoparticles gradually redshifts from 500 nm to 550 nm. Meanwhile, changing the deposition voltage can effectively control the coloring behavior of the deposited electrochromic device, such as... Figure 2As shown in (b), the deposition-type electrochromic device exhibits different colors such as yellow, orange, red, purple, and green.
[0042] like Figure 3 As shown, within the set operating voltage range, at different scan rates, the deposition-type electrochromic device can still maintain good deposition and dissolution response characteristics, exhibiting a stable and fast response across a wide range of scan rates from slow to fast.
[0043] like Figure 4 As shown, the transmittance of the deposition-type electrochromic device remained unchanged from 0V to -1.95V. However, when the voltage exceeded -1.95V, the transmittance began to decrease, indicating that silver ions began to continuously deposit onto the working electrode. This also suggests that the working cutoff voltage for silver nucleation must be at least above -1.95V. Subsequently, as the voltage increased, the transmittance of the deposition-type electrochromic device continuously decreased until it reached a minimum of 6.8% at around -1.53V. At this point, it exhibited a mirror-like state, and the transmittance change (ΔT) of the device reached 75%.
[0044] like Figure 5 As shown, after applying a fading voltage of 0.7V for 15 seconds, the deposited electrochromic device was able to return to its initial state, while the fading degree of the electrochromic device in the comparative example differed from that of the example by 20%. This indicates that C3N4-CNT significantly promotes Br... - / Br3 - The conversion reaction improves the conduction efficiency of the circuit current, which in turn facilitates the dissolution process of silver. Figure 5 (b) shows the cycling response curve of the deposition-type electrochromic device at a wavelength of 550 nm, which shows that it has a fast response speed and good cycling stability during both coloring and fading processes.
[0045] like Figure 6 As shown, the transmittance of the deposition-type electrochromic device remains unchanged with increasing resting time, indicating that PTMAB plays a role in fixing Br3. - This effect slows down the self-fading rate of deposition-type electrochromic devices. For example... Figure 7 As shown, the coloring efficiency of the deposition-type electrochromic device can reach 137.65 cm⁻¹. 2 / C indicates that deposition-type electrochromic devices have high silver deposition efficiency during the electrochromic process. For example... Figure 8 As shown, the fading time remains stable within 4 seconds even with the extension of the coloring time, further demonstrating that C3N4-CNT has significant advantages in improving the overall performance of the device.
[0046] Therefore, this invention employs the aforementioned highly stable deposition-type electrochromic device, its fabrication method, and its application, by fabricating a C3N4-CNT electrode to improve the performance of the counter electrode Br. - / Br3 - The conversion improves cycle performance, and the spin-coating of phenyltrimethylammonium bromide material promptly adsorbs excess Br3 generated in the electrolyte during the reaction. - Avoid Br3 - Self-diffusion to the working electrode leads to self-fading.
[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.
Claims
1. A method for fabricating a highly stable deposition-type electrochromic device, characterized in that: Includes the following steps: S1. Melamine and carbon nanotubes are added to an organic solvent and ultrasonically treated. After heating and stirring, the mixture is filtered, washed, and dried to obtain a powder for later use. S2. Place the powder obtained in S1 into the bottom of the quartz boat, cover the top of the quartz boat with the first ITO glass, place the lid of the quartz boat on the first ITO glass, wrap the entire quartz boat with tin foil, put it into a tube furnace for heating and reaction, and take it out after cooling to room temperature to obtain the C3N4-CNT electrode. S3. Mix Nafion solution, organic solvent and phenyltrimethylammonium bromide, and sonicate to obtain a mixed solution; S4. Place the C3N4-CNT electrode from S2 into a spin coater, drop the mixed solution from S3 onto the C3N4-CNT electrode, spin coat and heat to obtain the C3N4-CNT-PTMAB electrode. S5. Attach one side of the silicone pad to the second ITO glass, and attach the C3N4-CNT-PTMAB electrode from S4 to the other side of the silicone pad, and press them together to obtain a sandwich structure device. In S6 and S5, the silicone pads of the sandwich structure devices have gaps. Silver-containing electrolyte is injected into the gaps and then sealed to obtain a deposition-type electrochromic device.
2. The method for fabricating a highly stable deposition-type electrochromic device according to claim 1, characterized in that: The mass ratio of melamine to carbon nanotubes is 3:0.01-0.
05.
3. The method for fabricating a highly stable deposition-type electrochromic device according to claim 1, characterized in that: In S2, the conductive side of the first ITO glass is covered on the top of the quartz boat.
4. The method for fabricating a highly stable deposition-type electrochromic device according to claim 1, characterized in that: In S2, the heating atmosphere is air, the heating temperature is 500-600℃, the heating rate is 1-5℃ / min, and the heating time is 1-5h.
5. The method for fabricating a highly stable deposition-type electrochromic device according to claim 1, characterized in that: In S4, the spin coating speed is 1500-2500 r / min, the spin coating time is 10-30 s, the heating temperature is 50-70℃, and the heating time is 1-5 h.
6. The method for fabricating a highly stable deposition-type electrochromic device according to claim 1, characterized in that: In S5, the shape of the silicone pad is the same as that of the second ITO glass, and the silicone pad has a notch or gap on its side.
7. The method for fabricating a highly stable deposition-type electrochromic device according to claim 1, characterized in that: In S6, the silver-containing electrolyte includes one or more of silver nitrate, tetrabutylammonium bromide, citric acid, and polyvinylpyrrolidone.
8. The method for fabricating a highly stable deposition-type electrochromic device according to claim 1, characterized in that: Before use, the first ITO glass and the second ITO glass are cleaned, and then immersed in cleaning agent, water and anhydrous ethanol in sequence for 30 minutes by ultrasonication. After drying, they are treated with ultraviolet ozone.
9. A highly stable deposition-type electrochromic device, characterized in that: The device is prepared according to any one of claims 1-8. It is a high-stability deposition-type electrochromic device.
10. An application of a highly stable deposition-type electrochromic device, characterized in that: The highly stable deposition-type electrochromic device according to claim 9 is applied to smart windows, low-power displays, and wearable color-changing devices.