A method for manufacturing an electrochromic device

Abstract

The application provides a preparation method of an electrochromic device. The preparation method comprises the following steps: preparing a first electrochromic layer: forming the first electrochromic layer on a first transparent conductive layer of a first substrate; preparing a second electrochromic layer: forming the second electrochromic layer on a second transparent conductive layer of a second substrate; assembling the electrochromic device: forming an electrolyte coating layer on the first electrochromic layer, and then covering the second electrochromic layer on the electrolyte coating layer to obtain the electrochromic device; wherein the first electrochromic layer and the second electrochromic layer are both cathode electrochromic materials or both anode electrochromic materials, and when a first voltage in a first direction is applied to the electrochromic device, the first electrochromic layer changes from a first color to a third color, and the second electrochromic layer remains unchanged in a second color. The application realizes switching between different colors and expands the selection range of electrochromic materials.

Description

[0001] This invention patent application is a divisional application of Chinese patent application filed on April 1, 2020, entitled "An electrochromic device and its color-changing method", with application number 202010249974.9. Technical Field

[0002] This invention belongs to the field of color-changing device technology, and specifically relates to a method for preparing an electrochromic device. Background Technology

[0003] Electrochromism refers to the phenomenon where the optical properties of a material undergo stable and reversible color changes under the influence of an applied electric field, manifesting as reversible changes in color and transparency. Materials exhibiting electrochromic properties are called electrochromic materials, and devices made from electrochromic materials are called electrochromic devices. Electrochromic devices have significant application prospects in fields such as photochromic glasses, electronic displays, military concealment, and building energy conservation.

[0004] Existing electrochromic devices generally employ a stacked structure of a conductive layer, an electrochromic layer, an electrolyte layer, an ion storage layer (electrochromic layer), and another conductive layer. The electrochromic layer is one of the core components of the device, and the electrochromic materials constituting it can be divided into inorganic and organic electrochromic materials. Inorganic electrochromic materials have advantages such as stability and fast response, such as tungsten trioxide (WO3), vanadium pentoxide (V2O5), nickel oxide (NiO), and titanium dioxide (TiO2). Organic electrochromic materials are diverse, offer rich colors, and are easy to design, such as violet and polythiophene. Electrochromic materials can also be classified into cathodic and anodic electrochromic materials based on their color change. Cathodic electrochromic materials gain electrons and undergo a reduction reaction, switching between coloring and fading; anodic electrochromic materials lose electrons and undergo an oxidation reaction, also switching between coloring and fading.

[0005] Currently, most electrochromic devices are complex to manufacture and offer limited color variations, making it difficult to meet the demands of multi-color displays and personalized customization. To achieve color switching in electrochromic devices, existing technologies employ cathode and anodic electrochromic materials with mutually compatible color changes to assemble the devices. For example, a cathode electrochromic material with a color-changing range from red to colorless and an anodic electrochromic material with a color-changing range from colorless to blue can be used to assemble the device, enabling switching between red and blue.

[0006] CN 105278198A discloses a complementary inorganic all-solid-state electrochromic device and its fabrication method. The device comprises, from bottom to top, a substrate, a transparent conductive layer, an anode electrochromic layer, an ion storage layer, a fast ion transport layer, a cathode electrochromic layer, and a transparent conductive layer. CN 105607375A discloses a high-throughput screening electrochromic device for solid-state inorganic electrochromic materials and its fabrication method. Each electrochromic device unit, starting from the lower transparent conductive layer, is sequentially plated with a cathode electrochromic layer, a solid electrolyte layer, an anode electrochromic layer, and an upper transparent layer from the inside out. CN110109311A discloses an all-solid-state electrochromic device and its fabrication method. The device is composed of a substrate A, a transparent conductive layer A, an anode electrochromic layer, a solid electrolyte layer, a cathode electrochromic layer, a transparent conductive layer B, and a substrate B, arranged sequentially. The cathode electrochromic layer is a tungsten oxide thin film doped with metal atoms, and the anode electrochromic layer is a nickel oxide thin film doped with metal atoms. These electrochromic devices all employ a structure that combines a cathode electrochromic layer and an anode electrochromic layer.

[0007] However, due to the limited variety of electrochromic materials currently available, it may be difficult to find a matching cathode (or anode) electrochromic material for a given anodic (or cathode) electrochromic material, requiring independent design and development. Furthermore, those that do match the color may all be either anodic or cathode electrochromic materials. This makes the practical application of electrochromic devices with the aforementioned structure susceptible to limitations in color, materials, or manufacturing processes, hindering their expansion to support switching between a wider range of colors. Summary of the Invention

[0008] To address the shortcomings of existing technologies, the present invention aims to provide an electrochromic device and its color-changing method. This electrochromic device employs a structure with two electrochromic layers, both made of anodic or cathodic electrochromic materials. Combined with a specific color-changing method, it achieves switching between different colors, expands the selection range of electrochromic materials, and is easily extended to switching between more colors, thus meeting the needs of multi-color display and personalized customization.

[0009] To achieve this objective, the present invention adopts the following technical solution:

[0010] In a first aspect, the present invention provides an electrochromic device, the electrochromic device comprising a first substrate, a first transparent conductive layer, a first electrochromic layer, an electrolyte layer, a second electrochromic layer, a second transparent conductive layer, and a second substrate stacked sequentially.

[0011] The materials of the first electrochromic layer and the second electrochromic layer are either both cathode electrochromic materials or both anodic electrochromic materials.

[0012] The electrochromic device provided by this invention uses either a cathode electrochromic material or an anode electrochromic material for both electrochromic layers. Combined with a specific color-changing method, it can switch between different colors, thus expanding the range of electrochromic materials that can be selected, as the materials of the two electrochromic layers are not limited to a combination of cathode and anode electrochromic materials.

[0013] In one embodiment of the present invention, the first transparent conductive layer and the second transparent conductive layer are each independently formed from at least one of indium-tin oxide (ITO), aluminum zinc oxide (AZO), fluorine-doped tin oxide (FTO), silver nanowires, graphene, carbon nanotubes, metal meshes, and silver nanoparticles.

[0014] In one embodiment of the present invention, the thickness of the first transparent conductive layer and the second transparent conductive layer are each independently 1-1000nm, for example, they can be 1nm, 2nm, 5nm, 8nm, 10nm, 15nm, 20nm, 25nm, 50nm, 70nm, 100nm, 150nm, 200nm, 250nm, 300nm, 350nm, 400nm, 450nm, 500nm, 550nm, 600nm, 650nm, 700nm, 750nm, 800nm, 850nm, 900nm, 950nm or 1000nm, etc.

[0015] In this field, cathode electrochromic materials include cathode electrochromic reduced-state coloring materials, cathode electrochromic oxidized-state coloring materials, and cathode electrochromic multicolor materials.

[0016] Anodic electrochromic materials include anodic electrochromic reduced-state coloring materials, anodic electrochromic oxidized-state coloring materials, and anodic electrochromic multicolor materials.

[0017] Among them, the initial state of the cathode electrochromic reduced-state coloring material is colorless, and it becomes colored after gaining electrons and reducing to a reduced state; such materials include TiO2, WO3, Nb2O5, MoO3, Ta2O5, viologen and its derivatives, etc.

[0018] Cathodic electrochromic oxidized coloring materials are initially colored, but become colorless upon gaining electrons and reducing to a colorless state; such materials include Prussian blue and its derivatives, ruthenium purple and its derivatives, etc.

[0019] The color change of cathode electrochromic multicolor materials can be multiple color changes, for example, the initial state is color a, the intermediate state after gaining electrons is color b, and the reduced state after gaining electrons becomes color c; or it can be a two-color change, for example, the initial state is color a', and the reduced state after gaining electrons becomes color c'; such materials include CoO. x , Rh2O3, ferrocene and its derivatives, etc.

[0020] Anodic electrochromic reducing-state coloring materials are initially colored, but become colorless upon losing electrons and oxidizing; such materials include polythiophene and its derivatives.

[0021] Anodic electrochromic oxidized coloring materials are initially colorless, but become colored after losing electrons; such materials include NiO, IrO2, polytriphenylamines and their derivatives, etc.

[0022] The color change of anodic electrochromic polychromatic materials can be multiple color changes, such as the initial state being color d, the intermediate state after losing electrons being color e, and the oxidized state after losing electrons becoming color f; or a two-color change, such as the initial state being color d', and the oxidized state after losing electrons becoming color f'; such materials include V2O5, MnO2, polyaniline and its derivatives, polypyrrole and its derivatives, etc.

[0023] The materials of the first and second electrochromic layers of the electrochromic device provided by this invention can be selected from a cathode electrochromic reduced-state coloring material, a cathode electrochromic oxidized-state coloring material, and a cathode electrochromic multicolor material, respectively. Alternatively, the materials of the first and second electrochromic layers can also be selected from an anode electrochromic reduced-state coloring material, an anode electrochromic oxidized-state coloring material, and an anode electrochromic multicolor material, respectively. Combined with a specific color-changing method, switching between different colors is possible. Different types of materials can be matched according to the color requirements of the end product.

[0024] In one embodiment of the present invention, the materials of the first electrochromic layer and the second electrochromic layer are not simultaneously cathode electrochromic polychromatic materials, nor are they simultaneously anode electrochromic polychromatic materials.

[0025] In one embodiment of the present invention, the materials of the first electrochromic layer and the second electrochromic layer are neither cathode electrochromic polychromatic materials nor anodic electrochromic polychromatic materials.

[0026] Because the selection and color matching of cathode and anodic electrochromic multicolor materials are complex, when the end product requires electrochromic devices to switch between two color states, cathode electrochromic reduced-state coloring materials, cathode electrochromic oxidized-state coloring materials, and anodic electrochromic reduced-state and anodic oxidized-state coloring materials are preferred. It is understood that this does not preclude the use of cathode and anodic electrochromic multicolor materials.

[0027] In one embodiment of the present invention, the materials of the first electrochromic layer and the second electrochromic layer are either cathode electrochromic reduced-state coloring materials, cathode electrochromic oxidized-state coloring materials, anodic electrochromic reduced-state coloring materials, or anodic electrochromic oxidized-state coloring materials. The resulting electrochromic device, after pretreatment, will have one layer (layer A) colored and the other layer (layer B) colorless when a forward voltage is applied; when a reverse voltage is applied, it will switch to one layer (layer A) being colorless and the other layer (layer B) being colored; the color can switch between the two colors.

[0028] In this invention, the materials of the two electrochromic layers can be either a cathode electrochromic reduced-state coloring material and a cathode electrochromic oxidized-state coloring material; or one can be an anodic electrochromic reduced-state coloring material and the other an anodic electrochromic oxidized-state coloring material. The resulting electrochromic device can switch between colorless and the superimposed color of the two electrochromic layers.

[0029] In one embodiment of the present invention, the first electrochromic layer and the second electrochromic layer are made of different materials. Specifically, taking the example that both electrochromic layers are made of cathode electrochromic reduced-state coloring materials, it is preferable that the materials of the first and second electrochromic layers are two materials selected from the cathode electrochromic reduced-state coloring materials. If the first and second electrochromic layers are made of the same material, the electrochromic device will not have a color switching effect after applying forward and reverse voltages. Therefore, in the present invention, the materials of the first and second electrochromic layers are preferably different materials.

[0030] In one embodiment of the present invention, the maximum charge transfer per unit area of ​​the first electrochromic layer is 0-35 C / cm². 2 And it does not include 0, for example it could be 0.05C / cm 2 0.1C / cm 2 0.5C / cm 2 1C / cm 2 2C / cm 2 5C / cm 28C / cm 2 10C / cm 2 12C / cm 2 15C / cm 2 18C / cm 2 20C / cm 2 22C / cm 2 25C / cm 2 28C / cm 2 30C / cm 2 32C / cm 2 Or 35C / cm 2 The second electrochromic layer has a maximum charge transfer rate of 0-35 C / cm² per unit area. 2 And it does not include 0, for example it could be 0.05C / cm 2 0.1C / cm 2 0.5C / cm 2 1C / cm 2 2C / cm 2 5C / cm 2 8C / cm 2 10C / cm 2 12C / cm 2 15C / cm 2 18C / cm 2 20C / cm 2 22C / cm 2 25C / cm 2 28C / cm 2 30C / cm 2 32C / cm 2 Or 35C / cm 2 wait.

[0031] In one embodiment of the present invention, the ratio of the maximum charge transfer per unit area of ​​the first electrochromic layer to that of the second electrochromic layer is 1:50-50:1, for example, it can be 1:50, 1:45, 1:40, 1:35, 1:30, 1:25, 1:20, 1:15, 1:10, 1:8, 1:6, 1:5, 1:3, 1:2, 1:1, 2:1, 3:1, 5:1, 6:1, 8:1, 10:1, 15:1, 20:1, 25:1, 30:1, 35:1, 40:1, 45:1 or 50:1; more preferably, it is 1:10-10:1.

[0032] The maximum charge transfer per unit area of ​​an electrochromic layer is related to the material type and the thickness of the electrochromic layer. For an electrochromic layer with a specific material, the maximum charge transfer per unit area increases with increasing thickness. If the thickness of the first and second electrochromic layers is too large, the maximum charge transfer per unit area will be too large, which may lead to a longer color change time, incomplete color change, and poor color switching effect. If the thickness of the first and second electrochromic layers is too small, the maximum charge transfer per unit area will be too small, which may result in a lighter color, poorer color changing effect, and shorter device lifespan. If the difference in the maximum charge transfer per unit area between the first and second electrochromic layers is too large, the difference in color depth between the two will also easily lead to poor color switching effect.

[0033] In one embodiment of the present invention, the electrolyte layer is a gel electrolyte layer, a liquid electrolyte layer or a solid electrolyte layer, more preferably a solid electrolyte layer, and even more preferably a solid polymer electrolyte layer.

[0034] In one embodiment of the present invention, the thickness of the electrolyte layer is 0.1-200 μm; for example, it can be 0.1 μm, 0.2 μm, 0.5 μm, 0.8 μm, 1 μm, 2 μm, 5 μm, 8 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 150 μm, 160 μm, 180 μm or 200 μm, etc.

[0035] This invention does not impose any special restrictions on the type of electrolyte layer. For example, a solid electrolyte layer made of the following materials can be selected: In one embodiment of this invention, the solid electrolyte layer contains neutral organic small molecules, the weight percentage of which is ≤30wt%, such as 25wt%, 20wt%, 15wt%, 10wt%, 5wt%, etc.; the molecular weight of which is ≤3000, such as 2500, 2000, 1500, 1000, 500, etc. In one embodiment of this invention, the solid electrolyte layer contains a solid electrolyte polymer, the solid electrolyte polymer having plasticizing groups linked by covalent bonds. In one embodiment of this invention, the solid electrolyte polymer is a copolymer of a monomer or oligomer and an ion-conducting polymer, the side chains of which have plasticizing groups. Further, the components of the solid electrolyte layer also include monomer or oligomer fragments with crosslinking groups on their side chains. The term "furthermore" in this invention refers to the fact that, in the above-described limitation, the composition of the solid electrolyte layer includes copolymers of monomers or oligomers and ionically conductive polymers, preferably the copolymers also include monomer or oligomer fragments with crosslinked groups on their side chains; the same interpretation applies to "furthermore" in the following text. The plasticizing groups and plasticizable groups refer to groups that can weaken the interactions between polymers and reduce the crystallinity of the polymers. In one embodiment of this invention, the solid electrolyte polymer is a plasticizing linear polymer and an ionically conductive polymer, which are chemically bonded together. The glass transition temperature of the plasticizing linear polymer is below -20°C. Further, the composition of the solid electrolyte layer also includes monomers or polymers with crosslinked groups on their side chains, and the monomers or polymers with crosslinked groups on their side chains are chemically bonded together with the plasticizing linear polymer and the ionically conductive polymer. In one embodiment of the present invention, the solid electrolyte polymer is a polymer with plasticizing groups on its side chains and a glass transition temperature below -20°C, and an ion-conducting polymer, which are chemically bonded together. Further, the solid electrolyte layer also includes monomers or polymers with crosslinking groups on their side chains, which are chemically bonded together with the polymer with plasticizing groups on its side chains and a glass transition temperature below -20°C, and the ion-conducting polymer. In another embodiment of the present invention, the solid electrolyte polymer is a brush-like polymer, which has a flexible polymer backbone, ion-conducting side chains, and immiscible side chains. Further, the solid electrolyte layer also includes monomers or oligomers with crosslinking groups on their side chains, which are chemically bonded to the brush-like polymer in the form of block copolymerization.The immiscible side chains described in this invention refer to side chains whose properties differ significantly from other side chains or polymers, making them ineffectively miscible. The brush-like polymer provided in this invention refers to a polymer whose main chain is a flexible polymer with two types of side chains: one type for ion conduction, and the other type of side chain whose properties differ significantly from the ion-conducting side chain, making them ineffectively miscible. Introducing such immiscible side chains in this invention can reduce the crystallinity of the polymer, placing it in a random state, thereby improving the overall ion conduction capability and transparency of the polymer. In one embodiment of this invention, the ion transfer layer is a solid flexible electrolyte layer. The polymer of the solid flexible electrolyte layer can be selected from the following four major categories of polymers. Where x, y, and z are each independently selected from integers greater than 0. The rectangles shown in the formula represent polymer blocks with ion-conducting functions (ion-conducting polymer blocks), and the ellipses represent monomers or polymers with side chains such as PR (plasticizing groups), CL (crosslinking groups), NM (immiscible groups), or IC (ion-conducting groups).

[0036] (1) A block copolymer (denoted as PEGPRCL) formed by copolymerizing an ion-conducting polymer block y (such as polyethylene glycol or other materials reported in the literature) with a monomer or polymer block x having a plasticizing group (PR) on its side chain, and a monomer or polymer block z having a crosslinking group (CL) on its side chain. Alternatively, a block copolymer (denoted as PEGPR) formed by copolymerizing an ion-conducting polymer block y (such as polyethylene glycol or other materials reported in the literature) with a monomer or polymer block x having a plasticizing group (PR) on its side chain.

[0037] (2) A block copolymer (denoted as PEGSPCL) is formed by copolymerizing ion-conducting polymer blocks y (such as polyethylene glycol or other materials reported in the literature) with linear plasticizing polymer (SP) blocks x (such as polyethylene, polybutene, polyisobutylene, siloxane, or other materials reported in the literature) having a glass transition temperature below -20°C, and monomers or polymer blocks z with crosslinking groups (CL) on their side chains. Alternatively, a block copolymer (denoted as PEGSP) is formed by chemically linking ion-conducting polymer blocks y (such as polyethylene glycol or other materials reported in the literature) with linear plasticizing polymer (SP) blocks x (such as polyethylene, polybutene, polyisobutylene, siloxane, or other materials reported in the literature) having a glass transition temperature below -20°C.

[0038] (3) A block copolymer (denoted as PEGSP-PRCL) is formed by chemically linking ion-conducting polymeric blocks y (such as polyethylene glycol or other materials reported in the literature) with plasticized polymeric (SP-PR) blocks x having plasticized side chains, and then copolymerizing them with monomeric or oligomeric (CL) blocks z having crosslinking groups on the side chains. Alternatively, a block copolymer (denoted as PEGSP-PR) is formed by chemically linking ion-conducting polymeric blocks y (such as polyethylene glycol or other materials reported in the literature) with plasticized polymeric (SP-PR) blocks x having plasticized side chains.

[0039] (4) A comb-shaped block copolymer (ICNMCL) is formed by chemically linking a flexible polymer block x with ion-conducting oligomers or polymers (such as polyethylene glycol or other materials reported in the literature) as side chains and a flexible polymer block y with side chains that are not miscible with the ion-conducting polymer (such as alkyl, aromatic, or alkyl-aromatic mixed side chains). This block copolymer is then copolymerized with a monomer or oligomer (CL) block z with crosslinking groups on its side chains. Alternatively, a comb-shaped block copolymer (ICNM) is formed by chemically linking a flexible polymer block x with ion-conducting oligomers or polymers (such as polyethylene glycol or other materials reported in the literature) as side chains and a flexible polymer block y with side chains that are not miscible with the ion-conducting polymer (such as alkyl, aromatic, or alkyl-aromatic mixed side chains).

[0040] The aforementioned polymeric materials used in the ion transfer layer also need to be blended with a certain amount of organic and / or inorganic salts to form an electrolyte precursor. The inorganic salts include, but are not limited to, lithium, sodium, potassium, magnesium, calcium, and aluminum salts; the organic salts include, but are not limited to, ionic liquids, such as EMITFSI and EMIOTF. Sometimes, an initiator is also needed to be introduced to blend and form the electrolyte precursor. The electrolyte precursor is then crosslinked through methods such as heating or photoinitiation to form the final all-solid-state electrolyte.

[0041] In this invention, the plasticizing group (PR) includes, but is not limited to, the following structures:

[0042]

[0043] Crosslinking groups (CL) include, but are not limited to, the following structures:

[0044]

[0045] The backbone of comb-like block copolymers includes, but is not limited to, the following structures:

[0046]

[0047] Ionic conductive groups (ICs) include, but are not limited to, the following structures:

[0048]

[0049] In one embodiment of the present invention, the materials of the first substrate and the second substrate are each independently glass or flexible.

[0050] The material is preferably a transparent material. The flexible material includes, but is not limited to, PET (polyethylene terephthalate), cyclic olefin copolymers, and cellulose triacetate.

[0051] In a second aspect, the present invention provides a method for changing the color of the electrochromic device described in the first aspect, the method comprising the following steps:

[0052] (1) Apply a second voltage in a second direction to the pre-treated electrochromic device, the second direction being opposite to the first direction, so that the first electrochromic layer changes from a third color to a first color, and the second electrochromic layer changes from a second color to a fourth color; the pre-treatment is: apply a first voltage in a first direction to the electrochromic device, so that the first electrochromic layer changes from a first color to a third color, and the second electrochromic layer remains unchanged in its second color;

[0053] (2) Apply a third voltage in the first direction to the pretreated electrochromic device, so that the first electrochromic layer changes from the first color to the third color, and the second electrochromic layer changes from the fourth color to the second color.

[0054] In this invention, the pretreatment process induces a reversible oxidation / reduction reaction in the first electrochromic layer through the gain and loss of electrons, causing its color to switch. Simultaneously, the second electrochromic layer undergoes a non-Faraday reaction and a partial irreversible electrochemical reaction, generating charges that balance the charge of the electrochromic device. At this point, the second electrochromic layer does not undergo any color-changing-related Faraday reactions, thus maintaining its color. After pretreatment, the electrochromic device can switch between different colors by cyclically applying voltages in opposite directions. Furthermore, the pretreatment step only needs to be performed during the first use of the electrochromic device; subsequent uses do not require further pretreatment. In contrast, existing electrochromic devices do not employ a pretreatment step during color change. This invention, by setting both electrochromic layers to be either anodic or cathodic electrochromic materials, combined with the specific color-changing method described above, enables the electrochromic device provided by this invention to switch between different colors, expanding the range of electrochromic materials that can be selected.

[0055] In practical applications, the pretreatment can be performed by the manufacturer of the electrochromic device or by the user during the first use, and those skilled in the art can choose according to actual needs.

[0056] It should be noted that the critical voltage V1 for changing the first electrochromic layer from the first color to the third color in the preprocessing step of this invention is higher than the critical voltage V1' for changing the first electrochromic layer from the first color to the third color in step (2). Therefore, if voltage V1' is applied to the electrochromic device of this invention according to the existing usage method of electrochromic devices, it is impossible to preprocess the electrochromic device, and thus it is impossible to achieve color switching. V1 can be measured by gradually increasing the voltage and observing the reversibility of the color change of the first electrochromic layer; or by measuring the cyclic volt-ampere curve of the electrochromic device.

[0057] In one embodiment of the present invention, the absolute value of the first voltage is greater than or equal to V1, wherein V1 is the critical voltage that causes the second electrochromic layer to undergo an irreversible electrochemical reaction.

[0058] The pretreatment step of this invention requires the use of a relatively high voltage (greater than or equal to V1, less than V2) to cause an irreversible electrochemical reaction in the second electrochromic layer, where V2 is the breakdown voltage of the electrochromic device. If the first voltage is greater than V2, a portion of the electrochromic layer material will undergo irreversible changes, the structure will be destroyed, leading to a decrease in the quality of the electrochromic device, or even damage.

[0059] In one embodiment of the present invention, the absolute value of the third voltage is less than the absolute value of the first voltage. During the color switching process, the third voltage is sufficient to allow the electrochromic layer material to undergo a sufficient reversible electrochemical reaction, without the need for an irreversible electrochemical reaction. Therefore, this voltage is less than the voltage required for the pretreatment step.

[0060] Thirdly, the present invention provides an electronic terminal that includes the electrochromic device as described in the first aspect.

[0061] The electronic terminal can be a consumer electronics product, door or window, cabinet, electronic tag, wearable device, smart glasses, phototherapy device, etc. For example, when the electrochromic device is applied to the above-mentioned electronic terminal, it can be set at any desired location such as the surface or inside of the terminal, and can achieve effects such as diversifying appearance, shielding privacy, status display, information differentiation, adjusting ambient light, and filtering / transmitting light of different preset wavelengths, depending on the specific application scenario.

[0062] Fourthly, the present invention provides a method for preparing an electrochromic device, the method comprising:

[0063] Preparation of the first electrochromic layer: The first electrochromic layer is formed on the first transparent conductive layer of the first substrate;

[0064] Preparation of the second electrochromic layer: A second electrochromic layer is formed on the second transparent conductive layer of the second substrate;

[0065] Assemble an electrochromic device: Form an electrolyte coating on the first electrochromic layer, then cover the electrolyte coating with a second electrochromic layer in a staggered manner, and cure it with ultraviolet light or heat to form a solid electrolyte layer, thus obtaining an electrochromic device.

[0066] The first electrochromic layer and the second electrochromic layer are both cathode or both are anodic electrochromic materials. When a first voltage in a first direction is applied to the electrochromic device, the first electrochromic layer changes from a first color to a third color, while the second electrochromic layer remains unchanged in its second color.

[0067] The solid electrolyte layer contains a solid electrolyte polymer.

[0068] Preferably, the method further includes: applying a first voltage in a first direction to the electrochromic device, causing the first electrochromic layer to change from a first color to a third color, while the second electrochromic layer retains its second color.

[0069] Preferably, the absolute value of the first voltage is greater than or equal to V1, where V1 is the critical voltage that causes the second electrochromic layer to undergo an irreversible electrochemical reaction.

[0070] Preferably, the absolute value of the first voltage is less than V2, where V2 is the voltage at which the electrochromic device is broken down.

[0071] Preferably, the first voltage is a positive voltage. When the potential of the first electrochromic layer is higher than the potential of the second electrochromic layer, the voltage direction is called positive.

[0072] Preferably, the first electrochromic layer and the second electrochromic layer are made of different materials.

[0073] Preferably, the preparation of the first electrochromic layer includes: dissolving 300 mg of poly-2-[(2-ethylhexyloxy)methyl]3,4-thiophene-1,4-dioxane in 10 mL of o-xylene, stirring magnetically for 10 h, then dropping the resulting solution onto a first transparent conductive layer plated on a first substrate, spin-coating, and drying to form the first electrochromic layer;

[0074] The preparation of the second electrochromic layer includes: dissolving 400 mg of poly(3-hexylthiophene) in 10 mL of chloroform, stirring magnetically for 10 h, then dropping the resulting solution onto the second transparent conductive layer plated on the second substrate, spin-coating, and drying to form the second electrochromic layer;

[0075] The assembly of the electrochromic device includes: mixing 10 wt% lithium perchlorate, 89.9 wt% polymer H precursor and 0.1 wt% azobisisobutyronitrile, coating the mixture onto the first electrochromic layer to form an electrolyte coating; then misaligning the second electrochromic layer over the electrolyte coating, and curing it with ultraviolet light to form an electrolyte layer, thereby obtaining the electrochromic device.

[0076] Preferably, the thickness of the first electrochromic layer is 200 nanometers and the thickness of the second electrochromic layer is 300 micrometers.

[0077] Preferably, the preparation of the first electrochromic layer includes: dissolving 600 mg of poly-2-[(2-ethylhexyloxy)methyl]3,4-thiophene-1,4-dioxane in 10 mL of o-xylene, stirring magnetically for 10 h, then dropping the resulting solution onto a first transparent conductive layer plated on a first substrate, spin-coating, and drying to form the first electrochromic layer;

[0078] The preparation of the second electrochromic layer includes: dissolving 50 mg of poly(3-hexylthiophene) in 10 mL of chloroform, stirring magnetically for 10 h, then dropping the resulting solution onto the second transparent conductive layer plated on the second substrate, spin-coating, and drying to form the second electrochromic layer;

[0079] The assembly of the electrochromic device includes: mixing 10 wt% lithium perchlorate, 89.9 wt% polymer B precursor and 0.1 wt% potassium hydroxide (85%), and coating the mixture onto the first electrochromic layer to form an electrolyte coating; then misaligning the second electrochromic layer over the electrolyte coating and curing it with ultraviolet light to form an electrolyte layer, thereby obtaining the electrochromic device.

[0080] Preferably, the material of the first electrochromic layer is poly-2-[(2-ethylhexyloxy)methyl]3,4-thiophene, and the material of the second electrochromic layer is NiO; the electrolyte coating is made by mixing 10wt% lithium perchlorate, 89.9wt% polymer E precursor and 0.1wt% carbonyl diimide.

[0081] Compared with the prior art, the present invention has the following beneficial effects:

[0082] The electrochromic device provided by this invention uses either cathode or anodic electrochromic materials for both electrochromic layers. Combined with a specific color-changing method, it can switch between different colors. This expands the selection range of electrochromic materials, eliminating the limitation of using only cathode and anodic electrochromic materials. This electrochromic device is easily adaptable to switching between more colors, meeting the needs of multi-color displays and personalized customization. Attached Figure Description

[0083] Figure 1 This is a schematic diagram of the structure of the electrochromic device provided in an embodiment of the present invention;

[0084] Wherein, 1 is the first substrate, 2 is the first transparent conductive layer, 3 is the first electrochromic layer, 4 is the electrolyte layer, 5 is the second electrochromic layer, 6 is the second transparent conductive layer, and 7 is the second substrate. Detailed Implementation

[0085] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments. Those skilled in the art should understand that the specific embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention.

[0086] In this embodiment of the invention, the preparation method of the electrolyte polymer component in the electrolyte layer is as follows:

[0087] The preparation method of polymer A (a solid electrolyte polymer belonging to PEGPRCL) is as follows:

[0088]

[0089] A mixture of PEG (polyethylene glycol) with bromoisobutyric acid ends, acrylate with plasticizing groups, crosslinking groups with two acrylic acids, a monovalent copper catalyst, and PMDETA (N,N,N',N",N"-pentamethyldiethylenetriamine) ligand was added to a suitable organic solvent. This mixture (which, without solvent, can also be used directly as an electrolyte precursor for device fabrication) was reacted at 100°C for 12 hours. The solvent was removed by diatomaceous earth filtration and vacuum distillation to obtain polymer A.

[0090] The preparation method of polymer B (a solid electrolyte polymer belonging to PEGPR) is as follows:

[0091]

[0092] PEG diamine (polyethylene glycol diamine) and phthaloyl chloride are added to a suitable organic solvent, and the mixture is directly polymerized under alkaline conditions to obtain a polymeric electrolyte (this mixture without solvent can also be used as an electrolyte precursor for direct device fabrication). After washing with water, separation, drying, and removal of the solvent, polymer B is obtained.

[0093] The preparation method of polymer C (a solid electrolyte polymer belonging to PEGSPCL) is as follows:

[0094]

[0095]

[0096] PEG (polyethylene glycol), polysiloxane diamine, crosslinking agent tetraamine, and condensing agent CDI (carbonyl diimidazole) are added to a suitable organic solvent (this mixture without solvent can also be used directly as an electrolyte precursor for device fabrication). The reaction is carried out at 90°C to obtain the polymer. After washing with water, separation, drying, and removal of the solvent, high molecular weight C is obtained.

[0097] The preparation method of polymer D (a type of solid electrolyte polymer belonging to PEGSP) is as follows:

[0098]

[0099] PEG (polyethylene glycol), polysiloxane diamine, and the condensing agent CDI (carbonyl diimidazole) are added to a suitable organic solvent (this mixture without solvent can also be used directly as an electrolyte precursor for device fabrication). The reaction is carried out at 120°C to obtain a polymer, which is then washed with water, separated, dried, and the solvent is removed to obtain polymer D.

[0100] The preparation method of polymer E (a type of solid electrolyte polymer belonging to PEGSP-PRCL) is as follows:

[0101]

[0102] PEG (polyethylene glycol), polysiloxane glycol, crosslinking agent tetraol, and condensing agent CDI (carbonyl diimidazole) are added to a suitable organic solvent (this mixture without solvent can also be used directly as an electrolyte precursor for device fabrication). The mixture is reacted at 100°C to obtain a polymer. After washing with water, separation, drying, and removal of the solvent, polymer E is obtained.

[0103] The preparation method of polymer F (a solid electrolyte polymer belonging to PEGSP-PR) is as follows:

[0104]

[0105] PEG (polyethylene glycol), polysiloxane glycol, and the condensing agent CDI (carbonyl diimidazole) are added to a suitable organic solvent (this mixture without solvent can also be used directly as an electrolyte precursor for device fabrication). The reaction is carried out at 100°C to obtain the polymer. After washing with water, separation, drying, and removal of the solvent, polymer F is obtained.

[0106] The preparation method of polymer G (a type of solid electrolyte polymer belonging to ICN-MCL) is as follows:

[0107]

[0108] Alkyl acrylate, polyethylene glycol acrylate, polyethylene diacrylate, and AIBN (azobisisobutyronitrile) are added to a suitable organic solvent (this mixture without solvent can also be used directly as an electrolyte precursor for device fabrication). A photo-reaction is then performed to obtain the polymer. After washing with water, separation, drying, and removal of the solvent, polymer G is obtained.

[0109] The preparation method of polymer H (a type of solid electrolyte polymer belonging to ICNM) is as follows:

[0110]

[0111] Alkyl acrylate, polyethylene glycol acrylate, and AIBN (azobisisobutyronitrile) are added to a suitable organic solvent (this mixture without solvent can also be used directly as an electrolyte precursor for device fabrication). A photo-reaction is then performed to obtain the polymer. After washing with water, separation, drying, and removal of the solvent, polymer H is obtained.

[0112] It should be noted that, in this embodiment of the invention, when the potential of the first electrochromic layer 3 is higher than the potential of the second electrochromic layer 5, the voltage direction is called positive; when the potential of the first electrochromic layer 3 is lower than the potential of the second electrochromic layer 5, the voltage direction is called negative.

[0113] In this embodiment of the invention, the method for testing the maximum charge transfer per unit area of ​​the electrochromic layer is as follows:

[0114] 1. The electrochromic layer to be tested is used as the working electrode, Ag / AgCl as the reference electrode, and Pt electrode as the counter electrode, and connected to a three-electrode system. The electrolyte solution is a propylene carbonate solution containing 50% lithium perchlorate.

[0115] 2. Cyclic voltammetry tests were performed on the above three-electrode system using an electrochemical workstation. The starting and ending voltages were set to 0V, the scan rate to 0.05V / s, the number of scan cycles to 6, and the sensitivity to e^(-2). The highest and lowest scanning voltages were adjusted appropriately according to the material of the electrochromic layer. The test was successful when the electrochromic layer showed a complete symmetrical redox peak during the scan.

[0116] 3. Integrate the area of ​​the cyclic voltammetry curve, and denote the result of the area integral as S;

[0117] 4. Calculate the maximum charge transfer per unit area, Q = S / (2 × V × A);

[0118] Where V is the scan rate when scanning the cyclic voltammetry curve, and A is the area of ​​the electrochromic layer immersed in the electrolyte solution.

[0119] Example 1

[0120] This embodiment provides an electrochromic device, the structural schematic of which is shown below. Figure 1 As shown, it includes a first substrate 1, a first transparent conductive layer 2, a first electrochromic layer 3, an electrolyte layer 4, a second electrochromic layer 5, a second transparent conductive layer 6, and a second substrate 7, which are stacked in sequence; wherein, the materials of the first electrochromic layer 3 and the second electrochromic layer 5 are both anodic electrochromic reduced-state coloring materials.

[0121] The fabrication method of this electrochromic device is as follows:

[0122] 1) Preparation of the first electrochromic layer 3:

[0123] 300 mg of poly-2-[(2-ethylhexyloxy)methyl]3,4-thieno-1,4-dioxane was dissolved in 10 mL of o-xylene and magnetically stirred for 10 h. The resulting solution was then dropped onto an ITO layer (first transparent conductive layer 2) deposited on a glass substrate (first substrate 1), spin-coated, and dried to form a first electrochromic layer 3 (200 nm thick). The maximum charge transfer per unit area of ​​the first electrochromic layer 3 was measured to be 3.3 C / cm². 2 .

[0124] 2) Preparation of the second electrochromic layer 5:

[0125] 400 mg of poly(3-hexylthiophene) (P3HT) was dissolved in 10 mL of chloroform and magnetically stirred for 10 h. The resulting solution was then dropped onto an ITO layer (second transparent conductive layer 6) deposited on a glass substrate (second substrate 7), spin-coated, and dried to form a second electrochromic layer 5 (300 nm thick). The maximum charge transfer per unit area of ​​the second electrochromic layer 5 was measured to be 4.2 C / cm². 2 The ratio of the maximum charge transfer per unit area of ​​the first electrochromic layer 3 to the second electrochromic layer 5 is 0.79:1.

[0126] 3) Assemble electrochromic devices:

[0127] 10 wt% lithium perchlorate, 89.9 wt% polymer H precursor and 0.1 wt% azobisisobutyronitrile are mixed and coated on the first electrochromic layer 3 to form an electrolyte coating; then the second electrochromic layer 5 (together with the ITO layer and the glass substrate) is misaligned and covered on the electrolyte coating, and ultraviolet curing is performed to form an electrolyte layer 4 (with a thickness of 50 μm) to obtain an electrochromic device.

[0128] 4) Electrode arrangement:

[0129] The materials of the first electrochromic layer 3 and the second electrochromic layer 5 exposed by misalignment are cleaned with acetone to expose the first transparent conductive layer 2 and the second transparent conductive layer 6. Copper paste is then attached to the conductive layers to serve as positive and negative electrodes, respectively.

[0130] This embodiment also provides a color-changing method for the above-mentioned electrochromic device, including the following steps:

[0131] (1) Perform preprocessing to apply a positive voltage:

[0132] The first electrochromic layer 3 is connected to the positive terminal of the power supply, and the second electrochromic layer 5 is connected to the negative terminal of the power supply. A positive voltage (1.8V) is applied to the device, causing the first electrochromic layer 3 to be oxidized from blue-violet to colorless, while the second electrochromic layer 5 retains its red color. This invention does not impose any particular restriction on the timing of the pretreatment; it can be performed at any time before the electrochromic device first switches between different colors, and after the electrode placement step of the aforementioned preparation method.

[0133] (2) Switching between different colors:

[0134] A reverse voltage (-1.0V) is applied to the electrochromic device, causing the first electrochromic layer 3 to be reduced from colorless to blue-violet, and the second electrochromic layer 5 to be oxidized from red to colorless; a forward voltage (0V) is applied to the electrochromic device, causing the first electrochromic layer 3 to be oxidized from blue-violet to colorless, and the second electrochromic layer 5 to be reduced from colorless to red; the reverse voltage (-1.0V) and the forward voltage (0V) are applied to the device in a cyclic manner, causing the device color to switch between blue-violet and red.

[0135] The electrochromic device provided in this embodiment can be used in consumer electronics, electronic tags, doors and windows, cabinets, wearable devices, smart glasses, phototherapy devices, and other end products. For example, when applied to phototherapy devices, these devices can be glasses, helmets, displays, etc., fabricated as lenses or display screens to filter / transmit light of different preset wavelengths, directing specific wavelengths of light to the user's eyes, thereby achieving effects such as adjusting jet lag, improving sleep quality, relieving fatigue, and soothing emotions.

[0136] Example 2

[0137] This embodiment provides an electrochromic device, the structural schematic of which is shown below. Figure 1 As shown, it includes a first substrate 1, a first transparent conductive layer 2, a first electrochromic layer 3, an electrolyte layer 4, a second electrochromic layer 5, a second transparent conductive layer 6, and a second substrate 7, which are stacked in sequence; wherein, the materials of the first electrochromic layer 3 and the second electrochromic layer 5 are both cathode electrochromic oxidative coloring materials.

[0138] The fabrication method of this electrochromic device is as follows:

[0139] 1) Preparation of the first electrochromic layer 3:

[0140] 80 mg of potassium ferricyanide was dissolved in 25 mL of deionized water, and 60 mg of nickel acetate was dissolved in 25 mL of deionized water. The solutions were stirred thoroughly. The potassium ferricyanide solution was added to the nickel acetate solution to form a precipitate, which was washed three times with water and ethanol, respectively. The precipitate was dried, and 50 mg was redispersed in 10 mL of deionized water to form a solution. The resulting solution was then dropped onto an ITO layer (first transparent conductive layer 2) deposited on a glass substrate (first substrate 1), spin-coated, and dried to form the first electrochromic layer 3 (Prussian blue type, 200 nm thick). The maximum charge transfer per unit area of ​​the first electrochromic layer 3 was measured to be 8.9 C / cm². 2 .

[0141] 2) Preparation of the second electrochromic layer 5:

[0142] First, prepare 50 mL of a 35 mmol / mL potassium chloride solution and deoxygenate it under nitrogen purging. Then, take 25 mL of this solution and dissolve tetrapotassium hexacyanorhenate hydrate in it. Use the remaining 25 mL of the deoxygenated potassium chloride solution to prepare a 1 mmol / mL ferric chloride solution. Quickly stir the two solutions with a magnetic stirrer to obtain a bright purple ruthenium violet colloidal suspension. Adjust the pH of the obtained colloidal solution to 2 with hydrochloric acid. Finally, under nitrogen purging, add 1 mL of a 1 mmol / mL ruthenium chloride solution. Transfer the resulting solution to an electrochemical cell. Using ITO (second transparent conductive layer 6) on a glass substrate (second substrate 7) as the electrode, cyclic voltammetry is used, cycling between -0.2 V and 0.6 V, to electrochemically deposit a ruthenium violet film onto the electrode to form a second electrochromic layer 5 (250 nm thick). The maximum charge transfer per unit area of ​​the second electrochromic layer 5 is measured to be 10.2 C / cm². 2 The ratio of the maximum charge transfer per unit area of ​​the first electrochromic layer 3 to the second electrochromic layer 5 is 0.87:1.

[0143] 3) Assemble electrochromic devices:

[0144] A mixture of 10 wt% lithium perchlorate, 89.9 wt% polymer G precursor, 40% KCl solution (40 mmol / mL), and 0.1 wt% azobisisobutyronitrile was coated onto the first electrochromic layer 3 to form an electrolyte coating. Then, the second electrochromic layer 5 (along with the ITO layer and the glass substrate) was misaligned and covered onto the electrolyte coating. Ultraviolet curing was performed to form an electrolyte layer 4 (10 μm thick) to obtain the electrochromic device.

[0145] 4) Electrode arrangement:

[0146] The materials of the first electrochromic layer 3 and the second electrochromic layer 5 exposed by misalignment are cleaned with acetone to expose the first transparent conductive layer 2 and the second transparent conductive layer 6. Copper paste is then attached to the conductive layers to serve as positive and negative electrodes, respectively.

[0147] This embodiment also provides a color-changing method for the above-mentioned electrochromic device, including the following steps:

[0148] (1) Perform preprocessing to apply reverse voltage:

[0149] A reverse voltage (-1.2V) is applied to the device, causing the first electrochromic layer 3 to be reduced from deep blue to colorless, while the second electrochromic layer 5 remains purple. The present invention does not impose any particular limitation on the timing of the pretreatment; it can be performed when the electrochromic device first switches between different colors, or immediately after the electrode arrangement step of the aforementioned fabrication method of the electrochromic device.

[0150] (2) Switching between different colors:

[0151] A forward voltage (0.5V) is applied to the electrochromic device, causing the first electrochromic layer 3 to be oxidized from colorless to dark blue, and the second electrochromic layer 5 to be reduced from purple to colorless; a reverse voltage (-0.5V) is applied to the electrochromic device, causing the first electrochromic layer 3 to be reduced from dark blue to colorless, and the second electrochromic layer 5 to be oxidized from colorless to purple; the forward voltage (0.5V) and the reverse voltage (-0.5V) are applied to the device cyclically, causing the device color to switch between dark blue and purple.

[0152] The electrochromic device provided in this embodiment can be used in consumer electronics, electronic tags, doors and windows, cabinets, wearable devices, smart glasses, phototherapy equipment, and other end products. For example, when applied to consumer electronics such as mobile phones, tablets, computers, and watches, it can be placed on the product casing, display screen, or any other location, thereby giving the consumer electronics a rich aesthetic effect and enabling the display of different status information based on different color states.

[0153] Example 3

[0154] This embodiment provides an electrochromic device, the structural schematic of which is shown below. Figure 1 As shown, it includes a first substrate 1, a first transparent conductive layer 2, a first electrochromic layer 3, an electrolyte layer 4, a second electrochromic layer 5, a second transparent conductive layer 6, and a second substrate 7, which are stacked in sequence; wherein, the materials of the first electrochromic layer 3 and the second electrochromic layer 5 are both cathode electrochromic reduced-state coloring materials.

[0155] The fabrication method of this electrochromic device is as follows:

[0156] 1) Preparation of the first electrochromic layer 3:

[0157] 100 mg of 99.9% pure tungsten powder was dissolved in 10 mL of 30 wt% hydrogen peroxide solution and stirred at room temperature for 4 h. After stirring, the lower precipitate was filtered off, and anhydrous ethanol and glacial acetic acid were added, followed by stirring for another 4 h. The resulting solution was then dropped onto an ITO layer (first transparent conductive layer 2) deposited on a glass substrate (first substrate 1), spin-coated, and dried at 450 °C to form the first electrochromic layer 3 (WO3, 10 nm thick). The maximum charge transfer per unit area of ​​the first electrochromic layer 3 was measured to be 7 C / cm². 2 .

[0158] 2) Preparation of the second electrochromic layer 5:

[0159] 130 mg of Nb₂O₅ powder was dissolved in a mixed solution of 2.5 mL glacial acetic acid and 12.5 mL butanol, and magnetically stirred for 10 h. The resulting solution was then dropped onto an ITO layer (second transparent conductive layer 6) deposited on a glass substrate (second substrate 7), spin-coated, and dried at 700 °C to form the second electrochromic layer 5 (50 nm thick). The maximum charge transfer per unit area of ​​the second electrochromic layer 5 was measured to be 13 C / cm². 2 The ratio of the maximum charge transfer per unit area of ​​the first electrochromic layer 3 to the second electrochromic layer 5 is 0.54:1.

[0160] 3) Assemble electrochromic devices:

[0161] A mixture of 10 wt% lithium perchlorate, 89.9 wt% polymeric C precursor, and 0.1 wt% carbonyl diimidazole is coated onto the first electrochromic layer 3 to form an electrolyte coating. Then, the second electrochromic layer 5 (together with the ITO layer and the glass substrate) is misaligned and covered onto the electrolyte coating. The mixture is then thermo-cured at 90°C to form an electrolyte layer 4 (80 μm thick), thus obtaining an electrochromic device.

[0162] 4) Electrode arrangement:

[0163] The materials of the first electrochromic layer 3 and the second electrochromic layer 5 exposed by misalignment are cleaned with acetone to expose the first transparent conductive layer 2 and the second transparent conductive layer 6. Copper paste is then attached to the conductive layers to serve as positive and negative electrodes, respectively.

[0164] This embodiment also provides a color-changing method for the above-mentioned electrochromic device, including the following steps:

[0165] (1) Perform preprocessing to apply reverse voltage:

[0166] A reverse voltage (-3.0V) is applied to the device, causing the first electrochromic layer 3 to be reduced from colorless to blue, while the second electrochromic layer 5 remains colorless. The present invention does not impose any particular limitation on the timing of the pretreatment; it can be performed when the electrochromic device first switches between different colors, or immediately after the electrode placement step of the aforementioned fabrication method of the electrochromic device.

[0167] (2) Switching between different colors:

[0168] A forward voltage (1.5V) is applied to the electrochromic device, causing the first electrochromic layer 3 to be oxidized from blue to colorless, and the second electrochromic layer 5 to be reduced from colorless to light gray. A reverse voltage (-1.5V) is applied to the electrochromic device, causing the first electrochromic layer 3 to be reduced from colorless to blue, and the second electrochromic layer 5 to be oxidized from light gray to colorless. The forward voltage (1.5V) and the reverse voltage (-1.5V) are applied to the device in a cyclic manner, causing the device color to switch between light gray and blue.

[0169] The electrochromic device provided in this embodiment can be used in consumer electronics, electronic tags, doors and windows, cabinets, wearable devices, smart glasses, phototherapy equipment, and other end products. For example, when applied to doors and windows, it can be used in the glass to adjust the color and transmittance of the glass according to user needs, thereby achieving effects such as privacy protection, ambient light regulation, and temperature control.

[0170] Example 4

[0171] This embodiment provides an electrochromic device, which differs from Embodiment 1 in that the materials of the first electrochromic layer 3 and the second electrochromic layer 5 are both anodic electrochromic oxidative coloring materials, and the raw materials of the electrolyte layer 4 are replaced with polymer F.

[0172] The first electrochromic layer 3 is made of NiO, which is formed by reactive sputtering using Ni as a metal target. The thickness is 90 nm, and the maximum charge transfer number per unit area is 18 C / cm². 2 The second electrochromic layer 5 is made of IrO2, formed by reactive sputtering using Ir as the metal target, with a thickness of 125 nm and a maximum charge transfer number per unit area of ​​25 C / cm². 2 The ratio of the maximum charge transfer per unit area of ​​the first electrochromic layer 3 to the second electrochromic layer 5 is 0.66:1; the electrolyte layer 4 is formed by mixing 10wt% lithium perchlorate, 89.9wt% polymer F precursor and 0.1wt% carbonyl diimidazole, and then thermally curing at 100°C, with a thickness of 50μm.

[0173] This embodiment also provides a color-changing method for the above-mentioned electrochromic device, including the following steps:

[0174] (1) Preprocessing by applying a positive voltage:

[0175] A positive voltage (3V) is applied to the device, causing the first electrochromic layer 3 to oxidize from colorless to brownish-red, while the second electrochromic layer 5 remains colorless. The present invention does not impose any particular limitation on the timing of the pretreatment; it can be performed when the electrochromic device first switches between different colors, or immediately after the electrode arrangement step of the aforementioned preparation method of the electrochromic device.

[0176] (2) Switching between different colors:

[0177] A reverse voltage (-1.8V) is applied to the electrochromic device, causing the first electrochromic layer 3 to be reduced from brownish-red to colorless, and the second electrochromic layer 5 to be oxidized from colorless to bluish-black. A forward voltage (1.8V) is applied to the electrochromic device, causing the first electrochromic layer 3 to be oxidized from colorless to brownish-red, and the second electrochromic layer 5 to be reduced from bluish-black to colorless. The reverse voltage (-1.8V) and the forward voltage (1.8V) are applied to the device in a cyclic manner, causing the device color to switch between bluish-black and brownish-red.

[0178] The electrochromic device provided in this embodiment can be used in consumer electronics, electronic tags, doors and windows, cabinets, wearable devices, smart glasses, phototherapy devices, and other end products. For example, when applied to cabinets, it can be used on the surface or glass of the cabinet to provide effects such as diverse appearance, privacy protection, and temperature regulation inside the cabinet.

[0179] Example 5

[0180] This embodiment provides an electrochromic device, which differs from Embodiment 1 in that 600 mg of poly-2-[(2-ethylhexyloxy)methyl]3,4-thieno-1,4-dioxane was weighed when preparing the first electrochromic layer 3, the spin-coated thickness was 800 nm, and the maximum charge transfer per unit area was 12.2 C / cm². 2 ; 50 mg of poly(3-hexylthiophene) (P3HT) was weighed when preparing the second electrochromic layer 5. The spin-coated thickness was 12 nm, and the maximum charge transfer number per unit area was 0.25 C / cm. 2 The ratio of the maximum charge transfer per unit area of ​​the first electrochromic layer 3 to the second electrochromic layer 5 is 48.8:1; the raw material of the electrolyte layer 4 is replaced with polymer B, which is formed by mixing 10wt% lithium perchlorate, 89.9wt% polymer B precursor and 0.1wt% potassium hydroxide of 85% for 12h, and the thickness is 50μm.

[0181] By applying a forward voltage (1.8V) to the electrochromic device provided in this embodiment for pretreatment, and then cyclically applying a reverse voltage (-1.0V) and a forward voltage (0.4V), the device color can switch between blue-violet and red.

[0182] The electrochromic device provided in this embodiment can be used in consumer electronics, electronic tags, doors and windows, cabinets, wearable devices, smart glasses, phototherapy equipment, and other end products. For example, when applied to wearable devices, it can be used in the casing or display area of ​​the device to achieve effects such as aesthetic diversification and light filtering.

[0183] Example 6

[0184] This embodiment provides an electrochromic device, which differs from Embodiment 1 in that the material of the first electrochromic layer 3 is a cathode electrochromic reduced-state coloring material, the material of the second electrochromic layer 5 is a cathode electrochromic oxidized-state coloring material, and the raw material of the electrolyte layer 4 is replaced with polymer A.

[0185] The first electrochromic layer 3 is made of WO3, and the preparation method is as described in Example 3. It has a thickness of 50 nm and a maximum charge transfer number per unit area of ​​20 C / cm². 2 The second electrochromic layer 5 is made of ruthenium violet, prepared according to the method described in Example 2, with a thickness of 250 nm and a maximum charge transfer number per unit area of ​​10.2 C / cm². 2 The ratio of the maximum charge transfer per unit area of ​​the first electrochromic layer 3 to the second electrochromic layer 5 is 1.96:1; the electrolyte layer 4 is formed by thermosetting at 100°C by mixing 10wt% lithium perchlorate, 89.9wt% polymer A precursor, 0.05wt% cuprous chloride and 0.1wt% N,N,N',N",N"-pentamethyldiethylenetriamine, with a thickness of 150μm.

[0186] By applying a reverse voltage (-3V) to the electrochromic device provided in this embodiment for pretreatment, and then cyclically applying a forward voltage (1.2V) and a reverse voltage (-1.5V), the device color can switch between colorless and superimposed colors (blue and purple).

[0187] The electrochromic device provided in this embodiment can be used in consumer electronics, electronic tags, doors and windows, cabinets, wearable devices, smart glasses, phototherapy equipment, and other end products. For example, when applied to electronic tags, it serves to display status and differentiate information.

[0188] Example 7

[0189] This embodiment provides an electrochromic device, which differs from Embodiment 1 in that the material of the first electrochromic layer 3 is an anodic electrochromic reduced-state coloring material, the material of the second electrochromic layer 5 is an anodic electrochromic oxidized-state coloring material, and the raw material of the electrolyte layer is replaced with polymer E.

[0190] The first electrochromic layer 3 is made of poly-2-[(2-ethylhexyloxy)methyl]3,4-thiophene, prepared according to Example 1, with a thickness of 200 nm and a maximum charge transfer number per unit area of ​​3.3 C / cm². 2 The second electrochromic layer 5 is made of NiO, prepared according to Example 4, with a thickness of 180 nm and a maximum charge transfer number per unit area of ​​32 C / cm². 2 The ratio of the maximum charge transfer per unit area of ​​the first electrochromic layer 3 to the second electrochromic layer 5 is 1:10; the electrolyte layer 4 is formed by mixing 10wt% lithium perchlorate, 89.9wt% polymer E precursor and 0.1wt% carbonyl diimide, and then thermally curing at 100°C, with a thickness of 30μm.

[0191] By applying a positive voltage (1.8V) to the electrochromic device provided in this embodiment for preprocessing, and then cyclically applying a reverse voltage (-1.0V) and a positive voltage (1V), the device color can switch between colorless and superimposed colors (brownish-black and blue-purple).

[0192] The electrochromic device provided in this embodiment can be used in consumer electronics, electronic tags, doors and windows, cabinets, wearable devices, smart glasses, phototherapy equipment and other end products.

[0193] Example 8

[0194] This embodiment provides an electrochromic device, which differs from Embodiment 2 in that 160 mg of potassium ferricyanide is weighed when preparing the first electrochromic layer 3, the spin-coated thickness is 400 nm, and the maximum charge transfer per unit area is 16 C / cm². 2 The second electrochromic layer 5 has a thickness of 250 nm and a maximum charge transfer number per unit area of ​​10.2 C / cm². 2 The ratio of the maximum charge transfer per unit area of ​​the first electrochromic layer 3 to the second electrochromic layer 5 is 1.57:1.

[0195] By applying a reverse voltage (-1.2V) to the electrochromic device provided in this embodiment for pretreatment, and then cyclically applying a forward voltage (0.5V) and a reverse voltage (-0.5V), the device's color can switch between deep blue and purple. The electrochromic device provided in this embodiment can be used in consumer electronics, electronic tags, doors and windows, cabinets, wearable devices, smart glasses, phototherapy equipment, and other end products.

[0196] Example 9

[0197] This embodiment provides an electrochromic device, which differs from Embodiment 3 in that the thickness of the first electrochromic layer 3 is 75 nm, and the maximum charge transfer number per unit area is 30 C / cm². 2 The second electrochromic layer 5 has a thickness of 20 nm and a maximum charge transfer number per unit area of ​​3 C / cm². 2 The ratio of the maximum charge transfer per unit area of ​​the first electrochromic layer 3 to that of the second electrochromic layer 5 is 10:1.

[0198] By applying a reverse voltage (-3V) to the electrochromic device provided in this embodiment for pretreatment, and then cyclically applying a forward voltage (1.5V) and a reverse voltage (-1.5V), the device color can switch between light gray and blue. The electrochromic device provided in this embodiment can be used in consumer electronics, electronic tags, doors and windows, cabinets, wearable devices, smart glasses, phototherapy equipment, and other end products.

[0199] Example 10

[0200] This embodiment provides an electrochromic device, the structural schematic of which is shown below. Figure 1 As shown, it includes a first substrate 1, a first transparent conductive layer 2, a first electrochromic layer 3, an electrolyte layer 4, a second electrochromic layer 5, a second transparent conductive layer 6, and a second substrate 7, which are stacked in sequence; wherein, the materials of the first electrochromic layer 3 and the second electrochromic layer 5 are both anodic electrochromic multicolor materials.

[0201] The fabrication method of this electrochromic device is as follows:

[0202] 1) Preparation of the first electrochromic layer 3:

[0203] The 0.1 mol / L aniline was dissolved in a 1 mol / L sulfuric acid solution using a constant current method, with an anode flow rate of 10 μA / cm. 2 A first electrochromic layer 3 (polyaniline film, 280 nm thick) was formed on an ITO layer deposited on a glass substrate by deposition at a current density of 30 min. The maximum charge transfer per unit area of ​​the first electrochromic layer 3 was measured to be 20 C / cm². 2 .

[0204] 2) Preparation of the second electrochromic layer 5:

[0205] 300 mg of V₂O₅ flaky crystals were crushed and placed in a crucible. The crucible was heated to 800 °C in a muffle furnace until completely melted into a fluid colloidal state. After holding at this temperature for 5 minutes, the mixture was poured into a container and 20 mL of deionized water was added. The mixture was stirred until homogeneous to obtain a V₂O₅ colloidal solution. This solution was then dropped onto an ITO layer deposited on a glass substrate and spin-coated to form a second electrochromic layer 5 (350 nm thick). The maximum charge transfer per unit area of ​​the second electrochromic layer 5 was measured to be 35 C / cm². 2 The ratio of the maximum charge transfer per unit area of ​​the first electrochromic layer 3 to the second electrochromic layer 5 is 0.57:1.

[0206] 3) Assemble electrochromic devices:

[0207] 10 wt% lithium perchlorate, 89.9 wt% polymer D precursor and 0.1 wt% carbonyl diimidazole are mixed and coated on the first electrochromic layer 3 to form an electrolyte coating; then the second electrochromic layer 5 (together with the ITO layer and the glass substrate) is misaligned and covered on the electrolyte coating, and thermosetting at 120°C to form an electrolyte layer 4 (60 μm thick) to obtain an electrochromic device.

[0208] 4) Electrode arrangement:

[0209] The materials of the first electrochromic layer 3 and the second electrochromic layer 5 exposed by misalignment are cleaned with acetone to expose the first transparent conductive layer 2 and the second transparent conductive layer 6. Copper paste is then attached to the conductive layers to serve as positive and negative electrodes, respectively.

[0210] This embodiment also provides a color-changing method for the above-mentioned electrochromic device, including the following steps:

[0211] (1) Perform preprocessing to apply a positive voltage:

[0212] A positive voltage (2.5V) is applied to the device, causing the first electrochromic layer 3 to oxidize from green to dark blue, while the second electrochromic layer 5 remains yellow. The present invention does not impose any particular limitation on the timing of the pretreatment; it can be performed when the electrochromic device first switches between different colors, or immediately after the electrode arrangement step of the aforementioned fabrication method of the electrochromic device.

[0213] (2) Switching between different colors:

[0214] Applying a reverse voltage (-1.0V) to the electrochromic device reduces the first electrochromic layer 3 from dark blue to green and oxidizes the second electrochromic layer 5 from yellow to grayish-black. Applying a forward voltage (1.2V) to the electrochromic device oxidizes the first electrochromic layer 3 from green to dark blue and reduces the second electrochromic layer 5 from grayish-black to yellow. Cyclicly applying forward voltage (1.2V) and reverse voltage (-1.0V) to the device allows for color switching.

[0215] The electrochromic device provided in this embodiment can be used in consumer electronics, electronic tags, doors and windows, cabinets, wearable devices, smart glasses, phototherapy equipment and other end products.

[0216] Example 11

[0217] This embodiment provides an electrochromic device, which differs from Embodiment 7 in that 20 mg of poly-2-[(2-ethylhexyloxy)methyl]3,4-thieno-1,4-dioxane was weighed when preparing the first electrochromic layer 3, the spin-coated thickness was 6 nm, and the maximum charge transfer per unit area was 0.1 C / cm. 2 The second electrochromic layer 5 has a thickness of 25 nm and a maximum charge transfer number per unit area of ​​5 C / cm². 2 The ratio of the maximum charge transfer per unit area of ​​the first electrochromic layer 3 to the second electrochromic layer 5 is 0.02:1.

[0218] By applying a positive voltage (1.8V) to the electrochromic device provided in this embodiment for preprocessing, and then cyclically applying a reverse voltage (-1.0V) and a positive voltage (1V), the device color can switch between colorless and superimposed colors (brownish-black and blue-purple).

[0219] The electrochromic device provided in this embodiment can be used in consumer electronics, electronic tags, doors and windows, cabinets, wearable devices, smart glasses, phototherapy equipment and other end products.

[0220] Comparative Example 1

[0221] The color switching is performed using the electrochromic device provided in Example 1. The difference between the method and Example 1 is that the device is directly and cyclically subjected to a positive voltage (1.2V) and a reverse voltage (-1.2V) to change color.

[0222] (1) When a positive voltage (1.2V) is applied to the device, the first electrochromic layer 3 cannot lose electrons and undergo oxidation, and the second electrochromic layer 5 cannot gain electrons and undergo reduction. Neither the first electrochromic layer 3 nor the second electrochromic layer 5 changes color.

[0223] (2) When a reverse voltage (-1.2V) is applied to the device, the first electrochromic layer 3 cannot gain electrons and undergo a reduction reaction, and the second electrochromic layer 5 cannot lose electrons and undergo an oxidation reaction. Neither the first electrochromic layer 3 nor the second electrochromic layer 5 changes color.

[0224] (3) When the positive voltage (1.2V) and the reverse voltage (-1.2V) are applied cyclically, the device color cannot be switched.

[0225] Since both the first electrochromic layer 3 and the second electrochromic layer 5 are anodic electrochromic reduced-state coloring materials, they are both in the reduced state in the initial state. Due to the low voltage potential, they cannot provide enough charge to oxidize and fade the material, so the device cannot switch colors.

[0226] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for preparing an electrochromic device, characterized in that, The preparation method includes: Preparation of the first electrochromic layer: The first electrochromic layer is formed on the first transparent conductive layer of the first substrate; Preparation of the second electrochromic layer: A second electrochromic layer is formed on the second transparent conductive layer of the second substrate; Assemble an electrochromic device: Form an electrolyte coating on the first electrochromic layer, then cover the electrolyte coating with a second electrochromic layer in a staggered manner, and cure it with ultraviolet light or heat to form a solid electrolyte layer, thus obtaining an electrochromic device. The first electrochromic layer and the second electrochromic layer are both cathode or both are anodic electrochromic materials. When a first voltage in a first direction is applied to the electrochromic device, the first electrochromic layer changes from a first color to a third color, while the second electrochromic layer remains unchanged in its second color. The solid electrolyte layer contains a solid electrolyte polymer.

2. The method for preparing the electrochromic device according to claim 1, characterized in that, The method further includes: applying a first voltage in a first direction to the electrochromic device, causing the first electrochromic layer to change from a first color to a third color, while the second electrochromic layer remains unchanged in its second color.

3. The method for preparing the electrochromic device according to claim 2, characterized in that, The absolute value of the first voltage is greater than or equal to V1, where V1 is the critical voltage that causes the second electrochromic layer to undergo an irreversible electrochemical reaction.

4. The method for preparing the electrochromic device according to claim 3, characterized in that, The absolute value of the first voltage is less than V2, where V2 is the voltage at which the electrochromic device breaks down.

5. The method for preparing the electrochromic device according to claim 2, characterized in that, The first voltage is a positive voltage. When the potential of the first electrochromic layer is higher than the potential of the second electrochromic layer, the voltage direction is called positive.

6. The method for preparing the electrochromic device according to claim 1, characterized in that, The first electrochromic layer and the second electrochromic layer are made of different materials.

7. The method for preparing the electrochromic device according to any one of claims 1 to 6, characterized in that, The preparation of the first electrochromic layer includes: dissolving 300 mg of poly2-[(2-ethylhexyloxy)methyl]3,4-thiophene-1,4-dioxane in 10 mL of o-xylene, stirring magnetically for 10 h, then dropping the resulting solution onto the first transparent conductive layer plated on the first substrate, spin-coating, and drying to form the first electrochromic layer. The preparation of the second electrochromic layer includes: dissolving 400 mg of poly(3-hexylthiophene) in 10 mL of chloroform, stirring magnetically for 10 h, then dropping the resulting solution onto the second transparent conductive layer plated on the second substrate, spin-coating, and drying to form the second electrochromic layer; The assembly of the electrochromic device includes: mixing 10 wt% lithium perchlorate, 89.9 wt% polymer H precursor and 0.1 wt% azobisisobutyronitrile, coating the mixture onto the first electrochromic layer to form an electrolyte coating; then misaligning the second electrochromic layer over the electrolyte coating, and curing it with ultraviolet light to form an electrolyte layer, thereby obtaining the electrochromic device.

8. The method for preparing the electrochromic device according to claim 7, characterized in that, The first electrochromic layer has a thickness of 200 nanometers, and the second electrochromic layer has a thickness of 300 micrometers.

9. The method for preparing the electrochromic device according to any one of claims 1 to 6, characterized in that, The preparation of the first electrochromic layer includes: dissolving 600 mg of poly-2-[(2-ethylhexyloxy)methyl]3,4-thiophene-1,4-dioxane in 10 mL of o-xylene, stirring magnetically for 10 h, then dropping the resulting solution onto the first transparent conductive layer plated on the first substrate, spin-coating, and drying to form the first electrochromic layer. The preparation of the second electrochromic layer includes: dissolving 50 mg of poly(3-hexylthiophene) in 10 mL of chloroform, stirring magnetically for 10 h, then dropping the resulting solution onto the second transparent conductive layer plated on the second substrate, spin-coating, and drying to form the second electrochromic layer; The assembly of the electrochromic device includes: mixing 10 wt% lithium perchlorate, 89.9 wt% polymer B precursor and 0.1 wt% potassium hydroxide (85%), and coating the mixture onto the first electrochromic layer to form an electrolyte coating; then misaligning the second electrochromic layer over the electrolyte coating and curing it with ultraviolet light to form an electrolyte layer, thereby obtaining the electrochromic device.

10. The method for preparing the electrochromic device according to any one of claims 1 to 6, characterized in that, The first electrochromic layer is made of poly-2-[(2-ethylhexyloxy)methyl]3,4-thiophene, and the second electrochromic layer is made of NiO. The electrolyte coating is made by mixing 10 wt% lithium perchlorate, 89.9 wt% polymer E precursor and 0.1 wt% carbonyl diimide.

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