Reversible metal electrodeposition type electrochromic device with high response speed

Abstract

The invention discloses a reversible metal electro-deposition type electrochromic device with a high response speed. The reversible metal electro-deposition type electrochromic device comprises a first conductive base material, a second conductive base material, a sealant and a reversible electro-deposition solution, the sealant is arranged between the peripheral areas of the first conductive base material and the second conductive base material along the circumferential direction, so that the two conductive base materials are mutually combined in a sealing manner and a cavity is defined; the reversible electrodeposition solution is arranged in the cavity; wherein the reversible electro-deposition solution comprises a reversible metal electro-deposition material and a medium body for promoting metal electro-deposition and dissolution; under the action of external field voltage, the reversible metal electrodeposition material can perform reversible metal electrodeposition and dissolution operation on the surface of the conductive substrate. According to the electrochromic device, rapid switching from a transparent state to a mirror surface state is achieved, stable switching between high reflectivity and high transparency is achieved, and the requirements for high-performance electrochromic devices in the fields of intelligent windows, display equipment, optical switches and the like can be met.

Description

Technical Field

[0001] The present invention relates to the technical field of electrochromism, and particularly to a reversible metal electrodeposition type electrochromic device with a fast response speed. Background Art

[0002] The reversible metal electrodeposition type electrochromic technology is a technology that realizes reversible changes in the optical properties (such as transparency and reflectivity) of materials through electrochemical methods. The core of this technology lies in using an external electric field or current to deposit metal ions on the electrode surface to form a mirror surface or dissolve to restore the transparent state, thereby realizing the switching of the optical state. Due to its characteristics of fast response and high contrast, this technology has broad application prospects in fields such as smart windows, display devices, and optical switches.

[0003] However, the existing reversible metal electrodeposition type electrochromic devices still face some challenges in practical applications. First, the response speed of traditional devices is relatively slow, usually taking more than ten seconds or even dozens of seconds to complete the switching from transparent to mirror or from mirror to transparent. This slow response speed is particularly insufficient in application scenarios that require rapid switching. Second, traditional devices also have deficiencies in optical performance, such as the reflectivity change not being fast and stable enough to meet the requirements of rapid switching in practical applications. These problems limit the application of the reversible metal electrodeposition type electrochromic technology in a wider range of fields. Therefore, the development of an electrochromic device with a fast response speed and excellent optical performance has become a research hotspot in this field. Summary of the Invention

[0004] In view of the above deficiencies of the prior art, the present invention provides a reversible metal electrodeposition type electrochromic device with a fast response speed to solve the technical problems such as slow response speed and unstable optical performance of traditional electrochromic devices.

[0005] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0006] A reversible metal electrodeposition type electrochromic device with a fast response speed, the electrochromic device comprising:

[0007] A substantially transparent first conductive substrate, which includes a first surface and a second surface, and the first surface faces the observer;

[0008] A substantially transparent second conductive substrate, which includes a third surface and a fourth surface, and the fourth surface faces away from the observer, and the first conductive substrate and the second conductive substrate are arranged in a spaced-apart relationship;

[0009] A sealant, which is basically circumferentially disposed between the outer peripheral regions of the first conductive substrate and the second conductive substrate to hermetically bond the second surface and the third surface to each other and define a cavity; and

[0010] A reversible electrodeposition solution, which is disposed in the cavity;

[0011] Wherein, the reversible electrodeposition solution includes a reversible metal electrodeposition material and a medium for promoting metal electrodeposition and dissolution; when the electrochromic device is under the action of an external field voltage, the reversible metal electrodeposition material can perform reversible metal electrodeposition and dissolution operations on one of the surfaces of the first conductive substrate or the second conductive substrate.

[0012] The electrochromic device of the present invention realizes reversible metal electrodeposition and dissolution under the action of an external field voltage by adopting a substantially transparent first conductive substrate and a second conductive substrate, and providing a cavity defined by a sealant therebetween, and a reversible electrodeposition solution containing a reversible metal electrodeposition material and a medium. This structural design not only ensures the rapid switching between the transparent and mirror states of the device, but also significantly improves the response speed of electrodeposition and dissolution due to the presence of the medium, thus solving the problem of slow response speed of traditional electrochromic devices and providing a basis for rapid switching of optical states.

[0013] As a preferred technical solution, the first conductive substrate is composed of a substantially transparent first substrate and a first transparent conductive layer deposited on the second surface of the first substrate; the second conductive substrate is composed of a substantially transparent second substrate and a second transparent conductive layer deposited on the third surface of the second substrate; the first transparent conductive layer and the second transparent conductive layer are in contact with the reversible electrodeposition solution.

[0014] As a preferred technical solution, the reversible metal electrodeposition material is a silver-containing compound; preferably, the reversible metal electrodeposition material is a silver salt compound; more preferably, the reversible metal electrodeposition material includes but is not limited to AgNO 3 、AgBr、AgClO 4 or one or a combination of AgCl. The present invention selects a silver-containing compound as the reversible metal electrodeposition material, especially a silver salt compound, such as AgNO 3 、AgBr、AgClO 4 or AgCl, etc. Not only the excellent optical properties of silver (such as high reflectivity) are utilized, but also the efficiency and reversibility of the metal electrodeposition process are ensured. The deposition and dissolution processes of silver are relatively fast and stable, which enables the device to switch between the transparent and mirror states more quickly and reliably, significantly improving the optical performance and service life of the device.

[0015] As a preferred technical solution, the dielectric is a cerium-containing compound; preferably, the dielectric is a cerium salt compound; more preferably, the dielectric is a salt formed by tetravalent cerium. The use of a cerium-containing compound as the dielectric in the present invention, especially a salt formed by tetravalent cerium, is one of the key innovations of the present invention. The salt formed by tetravalent cerium has unique redox characteristics in the electrochemical reaction, and can efficiently promote the deposition and dissolution processes of metal ions. Specifically, compared with tetravalent cerium, the reversible metal electrodeposition material silver (Ag) has a higher electron potential; however, electrons usually want to discard energy and transfer to a lower energy state. Therefore, when tetravalent cerium contacts the silver layer formed by deposition, silver transfers electrons to tetravalent cerium ions. As a result, the silver layer dissolves and reformed silver ions dissolve into the original solution, while tetravalent cerium ions are reduced to the trivalent state. The cerium-containing compound in the present invention acts as a dielectric and serves as an electron transfer medium, greatly improving the deposition metal dissolution reaction rate; moreover, due to the presence of cerium ions, the activation energy of metal deposition at the transparent conductive layer is also significantly reduced. Experiments show that after using tetravalent cerium salt as the dielectric, both the ON response speed and the OFF response speed of the device are significantly improved, both less than or equal to 5 seconds. This fast response speed enables the device to complete the switching from the transparent state to the mirror state and the recovery from the mirror state to the transparent state in an extremely short time, greatly enhancing the user experience. In addition, the addition of tetravalent cerium salt also improves the stability and conductivity of the electrolyte, further optimizing the overall performance of the device.

[0016] As a preferred technical solution, the reversible electrodeposition solution further includes an electrolyte composed of a supporting electrolyte and a solvent. The reversible electrodeposition solution in the present invention further includes an electrolyte composed of a supporting electrolyte and a solvent, and this design further optimizes the stability of the electrodeposition process. The presence of the supporting electrolyte helps to maintain the conductivity of the solution, ensure the uniform distribution of current, and thus improve the uniformity and efficiency of electrodeposition.

[0017] As a preferred technical solution, the supporting electrolyte is at least one inorganic salt selected from lithium salts, potassium salts or sodium salts; preferably, the lithium salt is at least one inorganic salt selected from LiBr, LiCl, LiI, LiBF 4 、LiClO 4 ; the potassium salt is at least one selected from KCl, KBr, KI; the sodium salt is at least one selected from NaCl, NaBr, NaI. As a preferred technical solution, the supporting electrolyte is a quaternary ammonium salt compound with an unspecified hydrocarbon group length; preferably, the quaternary ammonium salt compound is tetraethylammonium chloride (TEACl), tetraethylammonium bromide (TEABr), tetrabutylammonium bromide (TBABr), tetrabutylammonium perchlorate (TBAClO 4at least one of those in

[0018] As a preferred technical solution, the driving voltage of the electrochromic device in the ON state is -2.0V to -2.9V.

[0019] As a preferred technical solution, the driving voltage of the electrochromic device in the OFF state is +0.3V to +1.2V.

[0020] As a preferred technical solution, both the ON response speed and the OFF response speed of the electrochromic device are less than or equal to 5 seconds.

[0021] Advantages of the present invention:

[0022] The present invention provides a reversible metal electrodeposition type electrochromic device with a fast response speed. By innovatively introducing a cerium-containing compound as a dielectric in the reversible electrodeposition solution, not only a rapid switch from a transparent state to a mirror state is achieved, but also a stable conversion between a high reflectivity and a high transparency is realized. This design not only enhances the response speed of the electrodeposition and dissolution processes, but also maintains the optical performance and stability of the device, which helps to reduce energy consumption and extend the service life of the device.

[0023] Generally speaking, the electrochromic device of the present invention not only has excellent optical performance, but also has a fast response speed (both the ON and OFF response speeds are less than or equal to 5 seconds), and can meet the high-performance requirements in fields such as smart windows, automotive rearview mirrors, and optical switches. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a cross-sectional view of the reversible metal electrodeposition type electrochromic device according to an embodiment of the present invention.

[0025] Figure 2 It is a schematic diagram of the physical appearance of the reversible metal electrodeposition type electrochromic device according to an embodiment of the present invention.

[0026] Figure 3 It is a schematic circuit diagram of the metal electrodeposition coloring state of the reversible metal electrodeposition type electrochromic device according to an embodiment of the present invention.

[0027] Figure 4 It is a schematic circuit diagram of the transparent state of the reversible metal electrodeposition type electrochromic device according to an embodiment of the present invention.

[0028] Figure 5 It is the experimental data of the ON response speed and the OFF response speed of the reversible metal electrodeposition type electrochromic device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments in the following description are only examples, and other obvious variations can be conceived by those skilled in the art.

[0030] Embodiment

[0031] This embodiment has a reversible metal electrodeposition type electrochromic device with a fast response speed, which includes a substantially transparent first conductive substrate, a substantially transparent second conductive substrate, a sealant, and a reversible electrodeposition solution; the first conductive substrate includes a first surface and a second surface, and the first surface faces the observer; the second conductive substrate includes a third surface and a fourth surface, and the fourth surface faces away from the observer, and the first conductive substrate and the second conductive substrate are arranged in a spaced-apart relationship; the sealant is disposed substantially circumferentially between the outer peripheral regions of the first conductive substrate and the second conductive substrate to hermetically bond the second surface and the third surface to define a cavity; the reversible electrodeposition solution is disposed in the cavity; wherein, the reversible electrodeposition solution includes a reversible metal electrodeposition material and a medium that promotes metal electrodeposition and dissolution; when the electrochromic device is under the action of an external field voltage, the reversible metal electrodeposition material can perform reversible metal electrodeposition and dissolution operations on one of the surfaces of the first conductive substrate or the second conductive substrate.

[0032] In one preferred embodiment, the first conductive substrate is composed of a substantially transparent first substrate and a first transparent conductive layer deposited on the second surface of the first substrate; the second conductive substrate is composed of a substantially transparent second substrate and a second transparent conductive layer deposited on the third surface of the second substrate; the first transparent conductive layer and the second transparent conductive layer are in contact with the reversible electrodeposition solution. In one embodiment, the first substrate and the second substrate can be independently selected from one of substantially transparent glass, organic resin, or ceramic. The glass can be selected from ordinary electronic grade float soda-lime glass, medium silicon-aluminum glass, high silicon-aluminum glass, or high borosilicate glass; and the glass is colorless or light-colored glass. The first transparent conductive layer and the second transparent conductive layer can be independently selected from at least one of indium-doped tin oxide (ITO), fluorine-doped tin oxide (FTO), aluminum-doped zinc oxide (AZO), indium zinc oxide, or graphene.

[0033] In one preferred embodiment, the reversible metal electrodeposition material is a silver-containing compound; preferably, the reversible metal electrodeposition material is a silver salt compound; more preferably, the reversible metal electrodeposition material includes, but is not limited to, one or a combination of AgNO3, AgBr, AgClO4, or AgCl.

[0034] In one preferred embodiment, the dielectric is a cerium-containing compound; preferably, the dielectric is a cerium salt compound; more preferably, the dielectric is a salt formed by tetravalent cerium.

[0035] In one preferred embodiment, the reversible electrodeposition solution further includes an electrolyte solution composed of a supporting electrolyte and a solvent. In one preferred embodiment, the supporting electrolyte is at least one inorganic salt such as a lithium salt, a potassium salt, or a sodium salt; preferably, the lithium salt is at least one of LiBr, LiCl, LiI, LiBF 4 , LiClO 4 ; the potassium salt is at least one of KCl, KBr, KI; the sodium salt is at least one of NaCl, NaBr, NaI. In another preferred embodiment, the supporting electrolyte is a quaternary ammonium salt compound with an unspecified alkyl chain length; preferably, the quaternary ammonium salt compound is at least one of tetraethylammonium chloride (TEACl), tetraethylammonium bromide (TEABr), tetrabutylammonium bromide (TBABr), tetrabutylammonium perchlorate (TBAClO 4 ). The solvent is not particularly limited as long as it can stably dissolve materials, etc.; by way of example, solvents such as triglyme (TGM), propylene carbonate (PC), and dimethylformamide (DMF) can be selected.

[0036] In one preferred embodiment, the driving voltage of the electrochromic device in the ON state is -2.0 V to -2.9 V. The driving voltage of the electrochromic device in the OFF state is +0.3 V to +1.2 V. By selecting a suitable voltage range, rapid and stable reversible metal electrodeposition and dissolution operations can be achieved, thereby improving the response speed and optical performance of the device.

[0037] The specific embodiments described below are only for illustration, and those skilled in the art can think of other obvious variations.

[0038] Example 1

[0039] This example has a reversible metal electrodeposition type electrochromic device with a fast response speed, such as Figures 1 to 4As shown in the figure, it includes a first conductive substrate, a second conductive substrate, a sealant 15, and a reversible electrodeposition solution 30; the first conductive substrate is composed of a first glass substrate 10 and a first ITO transparent conductive layer 12 deposited on the second surface of the first glass substrate 10; the second conductive substrate is composed of a second glass substrate 20 and a second ITO transparent conductive layer 22 deposited on the third surface of the second glass substrate 20. The first conductive substrate and the second conductive substrate are arranged in a spaced-apart relationship, which can be specifically achieved by incorporating glass bead spacers with a diameter of 200 μm into the sealant 15. The sealant 15 is basically arranged circumferentially between the outer peripheral regions of the first conductive substrate and the second conductive substrate to hermetically bond the second surface and the third surface to each other and define a cavity, and the spacing distance of the cavity is about 200 μm. After the first glass substrate 10 and the second glass substrate 20 are bonded, a liquid filling port is left for filling the reversible electrodeposition solution 30 into the cavity with a thickness of 200 μm of the manufactured box by vacuum liquid filling method.

[0040] The preparation of the reversible electrodeposition solution 30 is specifically as follows: 100 mM of silver nitrate (AgNO 3 ) as the electrodeposition material containing Ag, 50 mM of ammonium cerium nitrate ((NH 4 ) 2 Ce(NO 3 ) 6 ) as the dielectric material, and 500 mM of lithium bromide (LiBr) as the supporting electrolyte are dissolved in the solvent DMF, and the reversible electrodeposition solution 30 is obtained after being modulated into an electrolyte.

[0041] The first conductive substrate and the second conductive substrate are respectively electrically led out by conductive clips, and then connected to an external power supply to form an electrical circuit. Figure 3 As shown in the figure is the drive circuit of the electrochromic device in the metal electrodeposition coloring state (i.e., ON state). By applying a DC drive voltage of -2.8 V to it, the precipitation of the silver metal layer can be achieved, and the coloring process of the electrochromic device is completed. Specifically, among them, the first ITO transparent conductive layer 12 on the first glass substrate 10 is the negative electrode, and the second ITO transparent conductive layer 22 on the second glass substrate 20 is the positive electrode; an Ag layer 35 is precipitated on the first ITO transparent conductive layer 12 on the negative electrode side to form a reflective mirror surface. Figure 4 As shown in the figure is the drive circuit of the electrochromic device in the transparent state (i.e., OFF state). After applying a reverse voltage of +1.2 V to it, the accumulated Ag layer 35 dissolves, and the optical device returns to the initial transparent state again.

[0042] The reflectance of the constructed reversible electrodeposition electrochromic device was evaluated using a microfiber spectrophotometer SR-4VN500-25 manufactured by Ocean Optics, Inc. in the United States. After setting the light intensity in the state without a sample to 100%, the incident angle and the reflection angle were both set to a 25° angle (with respect to the normal) by rotating the optical axis, and calibration was performed using a standard mirror. The sensitivity reflectance was obtained from the relative light intensity of the reflected light of the sample in the stationary state, and this sensitivity reflectance was used as the reflectance value of the device. Figure 5 The curve showing the change in reflectance over time under the drive of an external power supply is displayed. The results show that when using (NH 4 ) 2 Ce(NO 3 ) 6 as the dielectric, the ON response speed is 3.85 seconds and the OFF response speed is 4.5 seconds, showing a fast switching time. The ON response speed is defined as the time (unit: second) from when the ON voltage is applied in the transparent state until the reflectance increases from 10% of the initial reflectance to 65%. The OFF response speed is defined as the time (unit: second) from when the reflectance decreases from 65% to 10% of the initial transmittance.

[0043] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art of this industry should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification is only the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed.

Claims

1. A reversible metal electrodeposition electrochromic device with fast response speed, characterized in that: The electrochromic device comprises: a substantially transparent first conductive substrate comprising a first surface and a second surface, the first surface facing a viewer; a substantially transparent second conductive substrate comprising a third surface and a fourth surface, the fourth surface facing away from a viewer, the first conductive substrate and the second conductive substrate being arranged in a spaced-apart relationship; a sealant disposed substantially circumferentially between the first conductive substrate and the outer peripheral region of the second conductive substrate to sealingly bond the second surface and the third surface to each other and define a cavity; and a reversible electrodeposition solution disposed in the cavity; Wherein, the reversible electrodeposition solution includes a reversible metal electrodeposition material and a dielectric body that promotes metal electrodeposition and dissolution; when the electrochromic device is under the action of an external field voltage, the reversible metal electrodeposition material can perform reversible metal electrodeposition and dissolution operations on one of the surfaces of the first conductive substrate or the second conductive substrate.

2. The reversible metal electrodeposition electrochromic device with fast response speed as claimed in claim 1, characterized in that: The first conductive substrate consists of a substantially transparent first substrate and a first transparent conductive layer deposited on the second surface of the first substrate; the second conductive substrate consists of a substantially transparent second substrate and a second transparent conductive layer deposited on the third surface of the second substrate; the first transparent conductive layer and the second transparent conductive layer are in contact with a reversible electrodeposition solution.

3. The reversible metal electrodeposition electrochromic device with fast response speed as claimed in claim 1, characterized in that: The reversible metal electrodeposition material is a silver-containing compound; preferably, the reversible metal electrodeposition material is a silver salt compound; more preferably, the reversible metal electrodeposition material includes but is not limited to one of AgNO3, AgBr, AgClO4 or AgCl or a combination thereof.

4. The reversible metal electrodeposition electrochromic device with fast response speed as claimed in claim 1, characterized in that: The medium is a cerium-containing compound; preferably, the medium is a cerium salt compound; more preferably, the medium is a salt formed by tetravalent cerium.

5. The reversible metal electrodeposition electrochromic device with fast response speed as claimed in claim 1, characterized in that: The reversible electrodeposition solution also includes an electrolyte consisting of a supporting electrolyte and a solvent.

6. The reversible metal electrodeposition electrochromic device with fast response speed as claimed in claim 5, characterized in that: The supporting electrolyte is at least one inorganic salt selected from lithium salt, potassium salt or sodium salt; preferably, the lithium salt is at least one selected from LiBr, LiCl, LiI, LiBF4, LiClO4; the potassium salt is at least one selected from KCl, KBr, KI; the sodium salt is at least one selected from NaCl, NaBr, NaI.

7. The reversible metal electrodeposition electrochromic device with fast response speed as claimed in claim 5, characterized in that: The supporting electrolyte is a quaternary ammonium salt compound with an unspecified hydrocarbon group length; preferably, the quaternary ammonium salt compound is at least one of tetraethylammonium chloride, tetraethylammonium bromide, tetrabutylammonium bromide, and tetrabutylammonium perchlorate.

8. The reversible metal electrodeposition electrochromic device with fast response speed as claimed in claim 1, characterized in that: The driving voltage of the electrochromic device in the ON state is -2.0V to -2.9V.

9. The reversible metal electrodeposition electrochromic device with fast response speed as claimed in claim 1, characterized in that: The driving voltage of the electrochromic device in the OFF state is +0.3V to +1.2V.

10. The reversible metal electrodeposition electrochromic device with fast response speed as claimed in claim 1, characterized in that: The ON response speed and OFF response speed of the electrochromic device are both less than or equal to 5 seconds.

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