Multicolor Electrochromic Structures and Their Applications

Abstract

This invention discloses a multi-color electrochromic structure and its applications. The multi-color electrochromic structure includes a working electrode, an electrolyte, and a counter electrode, with the electrolyte distributed between the working electrode and the counter electrode. The working electrode includes a first reflective surface and a second reflective surface arranged opposite to each other and parallel to each other. A dielectric layer is disposed between the first and second reflective surfaces. The first reflective surface, the second reflective surface, and the dielectric layer form an optical cavity. The dielectric layer is mainly composed of an electrochromic material. The multi-color electrochromic structure of this invention can achieve the fusion of structural color and electrochromism, exhibiting a rich variety of color changes. Furthermore, its structure is simple, easy to prepare, and low in cost, showing broad application prospects.

Description

[0001] This application is a divisional application of the patent application filed on May 15, 2019, with application number 201910401595.4 and invention title "Multicolor Electrochromic Structure, Preparation Method Thereof and Application". Technical Field

[0002] This invention relates to an electrochromic device, specifically to a multi-color electrochromic structure, its preparation method and application, belonging to the field of optoelectronic technology. Background Technology

[0003] Electrochromism is a phenomenon in which the electronic structure and optical properties (reflectivity, transmittance, absorptivity, etc.) of electrochromic materials undergo stable and reversible changes under the influence of an applied electric field or current, manifesting as reversible changes in color and transparency. Electrochromic devices made from electrochromic materials are widely used in smart windows, displays, and imaging equipment. Traditionally, electrochromism can be divided into two models: transmissive electrochromic devices and reflective electrochromic devices. However, the color of an electrochromic device is determined solely by the electronic structure and optical properties of the electrochromic material itself, belonging to chemical color. For specific electrochromic materials or prepared electrochromic devices, the color change is limited, which greatly restricts the application of electrochromism in displays, imaging equipment, and other fields.

[0004] Document CN104423114A discloses an all-solid-state electrochromic composite device, which is mainly formed by superimposing a PVD decorative color layer containing a base color on the outer transparent conductive layer of a tungsten trioxide-based electrochromic device. When the electrochromic layer is transparent and colorless without voltage, the device displays the base color of the PVD itself; when voltage is applied to the electrochromic layer and it turns blue, the device displays a color that is a combination of blue and the PVD base color. By designing the PVD decorative color layer to be different colors, various color changes can be achieved. However, this method is based on the principle of color composite between the color of tungsten trioxide and the base color. Since tungsten trioxide only has two states, colorless to blue, the multi-color modulation achieved by this method is very limited. In addition, this scheme requires designing different PVD decorative color layers to be superimposed on the electrochromic transparent conductive layer, which is costly and increases the complexity of the entire device.

[0005] Developing multi-color electrochromic devices with unrestricted color modulation and relatively simple structure has become a pressing problem in this field. Summary of the Invention

[0006] The main objective of this invention is to provide a multicolor electrochromic structure, its preparation method and application, so as to overcome the shortcomings of the prior art.

[0007] To achieve the aforementioned objectives, the technical solution adopted by this invention includes:

[0008] One aspect of this invention provides a multi-color electrochromic structure, including a working electrode, an electrolyte, and a counter electrode. The electrolyte is distributed between the working electrode and the counter electrode. The working electrode includes an electrochromic layer. The electrochromic layer includes a first reflective surface and a second reflective surface arranged opposite to each other and parallel to each other. A dielectric layer is disposed between the first reflective surface and the second reflective surface. The first reflective surface, the second reflective surface, and the dielectric layer form an optical cavity. When incident light enters the optical cavity, there is a phase shift between the reflected light formed on the first reflective surface and the reflected light formed on the second reflective surface. d is the thickness of the dielectric layer. Let λ be the refractive index of the dielectric layer, and λ be the wavelength of the incident light. The angle of refraction of the incident light as it passes through the first reflecting surface is denoted as ...

[0009] Another aspect of the present invention provides a multi-color electrochromic structure, including a first reflective surface and a second reflective surface arranged opposite to each other and parallel to each other, with a dielectric layer disposed between the first reflective surface and the second reflective surface. The dielectric layer includes an electrochromic material. The first reflective surface, the second reflective surface, and the dielectric layer form an optical cavity, and when incident light enters the optical cavity, there is a phase shift between the reflected light formed on the first reflective surface and the reflected light formed on the second reflective surface. d is the thickness of the dielectric layer. Let λ be the refractive index of the dielectric layer, and λ be the wavelength of the incident light. The angle of refraction of the incident light as it passes through the first reflecting surface is denoted as ...

[0010] In some implementations, the first reflective surface is the first surface of the dielectric layer, and the second reflective surface is the interface between the second surface of the dielectric layer and the metal reflective layer, with the first surface and the second surface facing away from each other.

[0011] In some embodiments, the electrochromic layer includes a metallic reflective layer and at least one dielectric layer, the dielectric layer being primarily composed of an electrochromic material, such as an inorganic electrochromic material.

[0012] In some implementations, the metal reflective layer also serves as a current collector for the electrochromic layer.

[0013] As a preferred embodiment, the multicolor electrochromic structure is an all-solid-state structure.

[0014] Another aspect of the present invention provides a method for preparing the multicolor electrochromic structure, comprising:

[0015] Fabrication of a metal reflective layer and a dielectric layer to form a working electrode; and

[0016] The working electrode, electrolyte, and counter electrode are assembled to form a multicolor electrochromic structure.

[0017] Another aspect of the present invention provides a method for controlling the multicolor electrochromic structure, comprising:

[0018] Connect the working electrode and the counter electrode to the power supply to form a working circuit.

[0019] The potential difference between the working electrode and the counter electrode is adjusted to at least change the refractive index of the electrochromic material in the dielectric layer, thereby controlling the color of the multicolor electrochromic structure.

[0020] This invention also provides applications of the multi-color electrochromic structure, such as its use in the fabrication of electrochromic devices and image display devices.

[0021] Compared with existing technologies, the embodiments of the present invention can obtain a rich variety of structural colors by adjusting the material of the metal reflective layer, the material of the dielectric layer, and / or the thickness of the electrochromic layer. At the same time, by applying a voltage to the electrochromic layer, the refractive index of the electrochromic material is changed (for example, by inserting or de-extracting ions into the electrochromic material, causing a change in the refractive index of the electrochromic material), thereby changing the optical constants (refractive index and extinction factor) of the dielectric layer, ultimately leading to a change in the color of the electrochromic structure. This fusion of structural color and electrochromism can realize a colorful electrochromic structure with rich color variations. Moreover, its preparation process is simple and low-cost, suitable for large-scale production and application, and has broad application prospects in optoelectronic technology and other fields. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of a multicolor electrochromic structure in a typical embodiment of the present invention;

[0023] Figure 2 yes Figure 1 Schematic diagram of the working electrode in the middle;

[0024] Figure 3 This is a schematic diagram of the structure of the working electrode inside a multicolor electrochromic device according to Embodiment 1 of the present invention;

[0025] Figure 4A These are photographs of the working electrodes in the multicolor electrochromic device with different tungsten oxide thicknesses in Embodiment 1 of the present invention;

[0026] Figure 4B This is a photograph of the tungsten oxide layer formed directly on a PET plastic sheet in the control group of Example 1 of the present invention;

[0027] Figure 5These are photographs of a pink working electrode in Embodiment 1 of the present invention under different voltages;

[0028] Figure 6 The image shows the reflectance curves of a pink working electrode under different voltages in Embodiment 1 of the present invention.

[0029] Figure 7 These are photographs of a working electrode, originally blue, under different voltages in Embodiment 1 of the present invention.

[0030] Figure 8 The image shows the reflectance curves of a working electrode, originally blue, under different voltages in Embodiment 1 of the present invention.

[0031] Figure 9 This is a schematic diagram of the working electrode structure in a multicolor electrochromic device according to Embodiment 2 of the present invention;

[0032] Figure 10 These are photographs of the working electrodes in the multicolor electrochromic device with different tungsten oxide thicknesses in Embodiment 2 of the present invention;

[0033] Figure 11 This is a schematic diagram of the working electrode structure in a multicolor electrochromic device according to Embodiment 3 of the present invention;

[0034] Figure 12 These are photographs of the working electrodes in the multicolor electrochromic device with different nickel oxide thicknesses in Embodiment 3 of the present invention;

[0035] Figure 13 This is a schematic diagram of the electrochromic layer in a multicolor electrochromic device according to Embodiment 4 of the present invention;

[0036] Figure 14 These are images of the electrochromic electrode under different voltages in the multicolor electrochromic device with different tungsten oxide thicknesses and a silver optimization layer in Embodiment 4 of the present invention;

[0037] Figure 15 This is a schematic diagram of a multicolor electrochromic structure in another typical embodiment of the present invention. Detailed Implementation

[0038] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0039] Furthermore, it should be noted that in this specification, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0040] Some embodiments of the present invention provide a multi-color electrochromic structure including a first reflective surface and a second reflective surface arranged opposite to each other and parallel to each other, a dielectric layer disposed between the first reflective surface and the second reflective surface, the dielectric layer comprising an electrochromic material, the first reflective surface, the second reflective surface and the dielectric layer forming an optical cavity, and when incident light enters the optical cavity, the phase shift of the reflected light formed at the first reflective surface and the reflected light formed at the second reflective surface... d is the thickness of the dielectric layer. Let λ be the refractive index of the dielectric layer, and λ be the wavelength of the incident light. The angle of refraction of the incident light as it passes through the first reflecting surface is denoted as ...

[0041] In some more specific embodiments, the multicolor electrochromic structure may include a working electrode, an electrolyte, and a counter electrode, with the electrolyte distributed between the working electrode and the counter electrode. The working electrode includes a first reflective surface and a second reflective surface arranged opposite to each other and parallel to each other. A dielectric layer is disposed between the first reflective surface and the second reflective surface. The first reflective surface, the second reflective surface, and the dielectric layer form an optical cavity, and when incident light enters the optical cavity, there is a phase shift between the reflected light formed on the first reflective surface and the reflected light formed on the second reflective surface. d is the thickness of the dielectric layer. Let λ be the refractive index of the dielectric layer, and λ be the wavelength of the incident light. The angle of refraction of the incident light as it passes through the first reflecting surface is denoted as ...

[0042] A more specific embodiment of the present invention provides a multi-color electrochromic structure that may include a working electrode, an electrolyte, and a counter electrode. The electrolyte is distributed between the working electrode and the counter electrode. The working electrode includes an electrochromic layer. The electrochromic layer includes a first reflective surface and a second reflective surface arranged opposite to each other and parallel to each other. A dielectric layer is disposed between the first reflective surface and the second reflective surface. The first reflective surface, the second reflective surface, and the dielectric layer form an optical cavity. When incident light enters the optical cavity, there is a phase shift between the reflected light formed on the first reflective surface and the reflected light formed on the second reflective surface. d is the thickness of the dielectric layer. Let λ be the refractive index of the dielectric layer, and λ be the wavelength of the incident light. The angle of refraction of the incident light as it passes through the first reflecting surface is denoted as ...

[0043] Furthermore, in the aforementioned embodiments, the first reflective surface is the first surface of the dielectric layer, and the second reflective surface is the interface between the second surface of the dielectric layer and the metal reflective layer, with the first surface and the second surface arranged opposite to each other.

[0044] When the multicolor electrochromic structure provided in the foregoing embodiments of the present invention is in operation, the reflected light formed by the incident light on the first surface of the dielectric layer (i.e., the first reflecting surface) and the reflected light formed by the incident light passing through the dielectric layer on the surface of the metal layer (i.e., the second reflecting surface) interfere and superimpose.

[0045] Furthermore, if the refractive index of the medium material on the first surface of the medium layer is defined as... Then the reflection coefficient of the first reflecting surface in The incident angle of the incident light.

[0046] Furthermore, if the refractive index of the medium material on the second surface of the medium layer is defined as... Then the reflection coefficient of the second reflecting surface in The angle of refraction is the angle at which the incident light passes through the second reflecting surface.

[0047] Furthermore, the reflectance coefficient of the electrochromic layer is expressed as: Reflectivity is expressed as:

[0048] Furthermore, the working electrode includes a metal reflective layer and at least one dielectric layer, the dielectric layer being mainly composed of the electrochromic material.

[0049] In the foregoing embodiments of the present invention, the electrochromic material may be selected from organic electrochromic materials or inorganic electrochromic materials. Inorganic electrochromic materials may be oxides of Co, Rh, Ir, Ni, Cr, Mn, Fe, Ti, V, Nb, Ta, Mo, and W, such as LiNiO2 (lithium nickel oxide), IrO2, NiO, V2O5, LixCoO2 (lithium cobalt oxide), Rh2O3, CrO3, WO3, MoO3, Nb2O5, Ta2O5, or TiO2, and are not limited thereto. Organic electrochromic materials may be organic polymers, small organic molecules, metal supramolecular polymers, organometallic compounds, such as methyl viologen, violarin, polyaniline, polythiophene, polypyrrole, Prussian blue, organometallic chelates (e.g., titanium cyanide compounds), polydiyne, and are not limited thereto.

[0050] In the foregoing embodiments of the present invention, the type of electrolyte is not particularly limited, and liquid electrolytes, gel polymer electrolytes, or inorganic solid electrolytes can be used. In some embodiments, the electrolyte is in contact with the dielectric layer and provides a material for the movement of ions, such as hydrogen ions or lithium ions, that cause the electrochromic material to change or decolorize.

[0051] In some embodiments, the electrolyte may contain one or more compounds, such as H+. + 、Li + Al 3 + Na + K + 、Rb + or Cs + The electrolyte layer may contain lithium salt compounds, such as LiClO4, LiBF4, LiAsF6, or LiPF6. Ions contained in the electrolyte can influence the color change or light transmittance of the device as they are inserted into or removed from the dielectric layer according to the polarity of the applied voltage.

[0052] In some embodiments, the electrolyte may be a liquid electrolyte, such as aqueous solutions of LiCl, AlCl3, HCl, or H2SO4.

[0053] In some embodiments, the electrolyte may be a mixed electrolyte, such as a mixed electrolyte composed of two or more salts from aqueous systems, including LiCl, AlCl3, HCl, MgCl2, and ZnCl2. When using an electrolyte containing two or more ions, compared to using an electrolyte containing only a single ion, the electrochromic structure of the foregoing embodiments of the present invention can exhibit richer color changes and higher color saturation.

[0054] In some embodiments, the electrolyte may further comprise a carbonate compound-based electrolyte. Carbonate-based compounds have high dielectric constants, which can increase the ionic conductivity provided by lithium salts. At least one of the following can be used as the carbonate compound: PC (propylene carbonate), EC (ethylene carbonate), DMC (dimethyl carbonate), DEC (diethyl carbonate), and EMC (ethyl methyl carbonate). For example, organic-based propylene carbonate electrolytes such as LiClO4 or Na(ClO4)3 can be used.

[0055] In some embodiments, the electrolyte may be a gel electrolyte, such as PMMA-PEG-LiClO4, PVDF-PC-LiPF6, etc., but is not limited thereto.

[0056] In some preferred embodiments, when an inorganic solid electrolyte is used as the electrolyte, the electrolyte may contain LiPON or Ta₂O₅. For example, the electrolyte may be, but is not limited to, a Li-containing metal oxide film, such as LiTaO or LiPO. Furthermore, the inorganic solid electrolyte may be an electrolyte in which LiPON or Ta₂O₅ is supplemented with components such as B, S, and W, for example, LiBO₂+Li₂SO₄, LiAlF₄, LiNbO₃, Li₂O-B₂O₃, etc.

[0057] In some preferred embodiments, the electrolyte is an all-solid electrolyte, which can be combined with a solid dielectric layer, a metal reflective layer, a counter electrode, etc., to form an all-solid multicolor electrochromic structure.

[0058] In some more specific embodiments, the all-solid electrolyte within the aforementioned all-solid multicolor electrochromic structure can take the form of a solid ion-conducting layer. The color-changing principle of this type of all-solid multicolor electrochromic structure is as follows: the metal reflective layer and other layer materials constitute a metal-dielectric structure, and may also include other layers, such as an ion-conducting layer, an ion storage layer, and a transparent conductive layer. By adjusting the thickness of each layer to a suitable range, an electrochromic device with structural color can be fabricated. Furthermore, by applying a voltage, the refractive index of the electrochromic material can be adjusted, and the color of the all-solid multicolor electrochromic device can be further adjusted.

[0059] In some embodiments, the thickness of the dielectric layer is 0–3000 nm, preferably 100–500 nm, so as to make the color saturation of the multicolor electrochromic structure higher.

[0060] In some embodiments, the thickness of the metal reflective layer is preferably 20 nm or more, and more preferably 50 to 3000 nm.

[0061] In some embodiments, the material of the metal reflective layer may be selected from non-reactive metals, such as chromium, gold, silver, copper, tungsten, titanium or alloys thereof, and is not limited thereto.

[0062] In some preferred embodiments, the metal reflective layer also serves as a current collector for the dielectric layer. Therefore, the metal reflective layer can preferably be formed of a metallic material with high conductivity, such as silver (Ag) or copper (Cu).

[0063] In some embodiments, the counter electrode includes a transparent conductive electrode having an ion storage layer, the material of which may be selected from, but is not limited to, NiO, Fe2O3, TiO2, etc. The ion storage layer is in contact with the electrolyte.

[0064] In the foregoing embodiments of the present invention, the transparent conductive electrode can be formed by comprising a material having characteristics such as high light transmittance and low sheet resistance. For example, it can be formed by comprising any of the following: a transparent conductive oxide selected from ITO (indium tin oxide), FTO (fluorine-doped tin oxide), AZO (aluminum-doped zinc oxide), GZO (gallium-doped zinc oxide), ATO (antimony-doped tin oxide), IZO (indium-doped zinc oxide), NTO (niobium-doped titanium oxide), ZnO, OMO (oxide / metal / oxide), and CTO; silver (Ag) nanowires; a metal mesh; or OMO (oxide-metal oxide).

[0065] There are no particular limitations on the method for forming the transparent conductive electrode; any known method can be used without restriction. For example, a thin film electrode layer containing transparent conductive oxide particles can be formed on a glass base layer by methods such as sputtering or printing (screen printing, gravure printing, inkjet printing, etc.). In the case of a vacuum method, the thickness of the electrode layer thus prepared can be in the range of 10 nm to 500 nm, while in the case of a printing method, the thickness can be in the range of 0.1 μm to 20 μm. In one example, the visible light transmittance of the transparent conductive electrode layer can be from 70% to 95%.

[0066] In some embodiments, a metal material layer, particularly a thin metal layer, may be added to the dielectric layer to optimize the color of the multicolor film. Specifically, for certain materials or multicolor films of suitable thickness, adding a metal material of suitable thickness can improve the intensity difference of the reflectance curve, thereby improving the color saturation. The metal may be selected from Ag, Al, Cu, Ni, etc., but is not limited thereto. The thickness of the metal layer is preferably 0–30 nm, and particularly preferably 1–10 nm.

[0067] In some embodiments, semiconductor materials can be added to the dielectric layer to optimize the color of the multicolor thin film. For multicolor thin films of certain materials or thicknesses, adding a semiconductor material of appropriate thickness can improve the intensity difference of the reflectivity curve, thereby improving the color saturation. The semiconductor can be selected from Al2O3, SiO2, ZnS, MgF2, silicon nitride, etc., but is not limited to these. The thickness of the semiconductor is preferably 0–300 nm, and particularly preferably 1–100 nm.

[0068] Please see Figure 1 The present invention illustrates a multicolor electrochromic structure in a typical embodiment, which includes a working electrode 1, a counter electrode 3 and an electrolyte layer 2, wherein the electrolyte layer 2 is disposed between the working electrode 1 and the counter electrode 3.

[0069] The electrolyte layer 2 can be selected from suitable aqueous electrolyte, organic electrolyte, or gel electrolyte, such as aqueous solutions of LiCl, AlCl3, HCl, and H2SO4, propylene carbonate electrolyte of LiClO4, etc., and is not limited to these.

[0070] Please see again Figure 2 As shown, the working electrode 1 includes a substrate 10, a metal reflective layer 11, and a dielectric layer 12, wherein the dielectric layer 12 is composed of an electrochromic material.

[0071] Referring to the above, the structural color of the working electrode can be changed by adjusting the materials and thickness of the metal reflective layer and the dielectric layer. Furthermore, by adjusting the voltage and current applied to the working electrode, the color of the working electrode can be reversibly changed.

[0072] The electrochromic material can be an inorganic electrochromic material or an organic electrochromic material, but the former is preferred.

[0073] The substrate can be made of inorganic or organic materials, such as, but not limited to, glass, plexiglass, plastic sheets, wood panels, or metals.

[0074] In some embodiments, the electrolyte includes a liquid electrolyte, a gel electrolyte, or a solid electrolyte.

[0075] In some more specific implementations, the operating voltage of the multicolor electrochromic structure is -4V to +4V, but it is not limited to this.

[0076] In another typical embodiment of the present invention, see [reference needed]. Figure 15As shown, a multi-colored electrochromic structure may include a working electrode, an electrolyte, and a counter electrode. The working electrode may include a substrate 10, a metal reflective layer 11, and a dielectric layer 12. The electrolyte 13 may be in the form of an ion-conducting layer, and the counter electrode 15 may be a transparent conductive layer. The multi-colored electrochromic structure may also include an ion storage layer 14, which may be disposed between the ion-conducting layer and the transparent conductive layer. All these structural layers may be solid-state. By adjusting the thickness of each structural layer to a suitable range, an electrochromic device with structural colors can be fabricated. Furthermore, by applying a voltage, the refractive index of the electrochromic material can be adjusted, and the color of the multi-colored electrochromic structure can be further adjusted.

[0077] Another aspect of the present invention provides a method for preparing the multicolor electrochromic structure, comprising:

[0078] Fabrication of a metal reflective layer and a dielectric layer to form a working electrode; and

[0079] The working electrode, electrolyte, and counter electrode are assembled to form a multicolor electrochromic structure.

[0080] In some implementations, the metal reflective layer and dielectric layer can be formed by at least one of the following methods: magnetron sputtering, ion plating, electron beam evaporation, thermal evaporation, chemical vapor deposition, and electrochemical deposition.

[0081] More specifically, the dielectric layer can be prepared by methods such as magnetron sputtering, ion plating, electron beam evaporation, thermal evaporation, chemical vapor deposition, and electrochemical deposition.

[0082] More specifically, metal reflective layers can be prepared by methods such as magnetron sputtering, ion plating, electron beam evaporation, thermal evaporation, and chemical vapor deposition.

[0083] In some implementations, the liquid electrolyte can be encapsulated or the gel electrolyte can be tightly pressed together to form an electrolyte layer and bonded between the working electrode and the counter electrode.

[0084] Furthermore, the metal reflective layer and the dielectric layer can be formed sequentially on the substrate.

[0085] Another aspect of the present invention provides a method for controlling a multi-color electrochromic structure, comprising:

[0086] Connect the working electrode and the counter electrode to the power supply to form a working circuit.

[0087] The potential difference between the working electrode and the counter electrode is adjusted to at least change the refractive index of the electrochromic material within the dielectric layer, thereby controlling the color of the multicolor electrochromic structure. This control process can be dynamic.

[0088] In some implementations, the material of the metal reflective layer and / or the thickness and / or material of the dielectric layer can also be adjusted to adjust the color of the multicolor electrochromic structure.

[0089] Another aspect of this invention provides an electrochromic device incorporating the multi-color electrochromic structure. The electrochromic device may further include additional packaging structures, control modules, power modules, and other components, which can be conventionally integrated with the multi-color electrochromic structure.

[0090] Another aspect of the present invention provides a device that includes the multicolor electrochromic structure or the electrochromic device, such as electronic devices (e.g., display screens, imaging devices, and other image display devices), buildings, transportation equipment, etc., but is not limited thereto.

[0091] The multi-color electrochromic structure provided in this invention overcomes the limited color modulation of traditional organic or inorganic electrochromic devices by integrating diverse structural colors with electrochromic properties, thus enriching the color modulation of electrochromic devices and achieving dynamic control of multiple colors. The electrochromic electrode, i.e., the aforementioned working electrode, mainly consists of a metal reflective layer and a dielectric layer, with the dielectric layer composed of an electrochromic material. The electrochromic electrode can achieve a rich variety of structural colors by adjusting the metal layer material, dielectric layer material, and dielectric layer thickness. Simultaneously, by using the electrochromic electrode as the working electrode and applying voltage, ions in the electrolyte layer are inserted into or extracted from the electrochromic material, causing changes in the optical constants (refractive index and extinction factor) of the dielectric layer material, resulting in color changes. This multi-color electrochromic structure in this invention utilizes the fusion of structural colors and electrochromic properties to achieve rich and varied color changes in electrochromic materials, especially inorganic electrochromic materials. In addition, within the multicolor electrochromic structure provided in this embodiment of the invention, the metal reflective layer can also serve as a current collector for the dielectric layer, thereby further simplifying the multicolor electrochromic structure, reducing costs, and making the device thinner and more compact.

[0092] The technical solution of the present invention will be further described in detail below through several embodiments and in conjunction with the accompanying drawings. However, the selected embodiments are only for illustrating the present invention and do not limit the scope of the present invention.

[0093] Example 1 This example discloses a multi-color electrochromic device including a working electrode, an electrolyte layer and a counter electrode, wherein the electrolyte layer is disposed between the working electrode and the counter electrode.

[0094] See Figure 3 As shown, the working electrode includes a metal reflective layer and a dielectric layer disposed on a substrate, wherein the metal reflective layer is formed of tungsten and the dielectric layer is formed of tungsten oxide. The substrate can be a PET plastic sheet, etc.

[0095] The working electrode is prepared as follows: On a clean PET plastic plate, a tungsten film is first magnetron sputtered, preferably with a thickness of about 100 nm. Then, a tungsten oxide layer is magnetron sputtered on the tungsten film, preferably with a thickness of 150 nm to 400 nm.

[0096] Of course, the aforementioned tungsten film can also be prepared using methods known in the industry, such as electron beam evaporation, thermal evaporation, and ion plating. The aforementioned tungsten oxide layer can be prepared using methods known in the industry, such as electron beam evaporation, thermal evaporation, and electrochemical deposition.

[0097] See Figure 4A As shown, by controlling the thickness of the tungsten oxide layer, different colored dielectric layers can be obtained, which appear as colored films under visible light.

[0098] See Figure 4B As shown, as a control group, a tungsten oxide layer with a thickness of 150nm to 400nm was formed directly on a clean PET plastic sheet using magnetron sputtering, which appears colorless and transparent under visible light.

[0099] By combining the aforementioned working electrode with a pair of electrodes (e.g., a NiO counter electrode), encapsulating them with a LiClO4-PC electrolyte, and then extending a lead wire, a multi-color electrochromic device can be fabricated. The color of the resulting multi-color electrochromic device can be further modulated by applying a voltage.

[0100] Figures 5-6 This document presents reflectance modulation diagrams of some originally pink working electrodes in an open system at different voltages, along with color photographs (all under visible light) at three of these voltages. The open system test used Pt wire as the counter electrode and Ag / AgCl as the reference electrode. It can be seen that the color of the working electrode can be adjusted from red to yellow, and then from yellow to green.

[0101] Figure 7-Figure 8 This document presents reflectance modulation diagrams and color photographs at five different voltages in an open system for some of the originally blue working electrodes in Example 1. The open system test used Pt wire as the counter electrode and Ag / AgCl as the reference electrode. It can be seen that the color of the working electrode can change between different shades of blue.

[0102] Example 2: This example discloses a multi-color electrochromic device including a working electrode, an electrolyte layer and a counter electrode, wherein the electrolyte layer is disposed between the working electrode and the counter electrode.

[0103] See Figure 9As shown, the working electrode includes a metal reflective layer and a dielectric layer disposed on a substrate, wherein the metal reflective layer is formed of copper and the dielectric layer is formed of tungsten oxide. The substrate can be a PET plastic sheet, etc.

[0104] The working electrode is prepared as follows: On a clean PET plastic plate, a copper film is first magnetron sputtered, preferably with a thickness of about 100 nm. Then, a tungsten oxide layer is magnetron sputtered on the tungsten film, preferably with a thickness of 150 nm to 400 nm.

[0105] Of course, the aforementioned copper film can also be prepared using methods known in the industry, such as electron beam evaporation, ion plating, and thermal evaporation. The aforementioned tungsten oxide layer can also be prepared using methods known in the industry, such as electron beam evaporation, thermal evaporation, and electrochemical deposition.

[0106] See Figure 10 As shown, by controlling the thickness of the tungsten oxide layer, different colored dielectric layers can be obtained, which appear as colored films.

[0107] Referring to Example 1, after assembling a working electrode that is initially red with a counter electrode and a PMMA-PEG-LiClO4 gel electrolyte to form a multicolor electrochromic device, when a power supply with a voltage of -2.5V to +2.5V is applied, the color of the working electrode will change in real time between red, orange, yellow and green.

[0108] Example 3: The multi-color electrochromic device disclosed in this example includes a working electrode, an electrolyte layer and a counter electrode, wherein the electrolyte layer is disposed between the working electrode and the counter electrode.

[0109] See Figure 11 As shown, the working electrode includes a metal reflective layer and a dielectric layer disposed on a substrate, wherein the metal reflective layer is formed of silver and the dielectric layer is formed of nickel oxide. The substrate can be a PET plastic sheet, etc.

[0110] The working electrode is prepared as follows: On a clean PET plastic plate, a silver film is first magnetron sputtered, preferably with a thickness of about 200 nm. Then, a nickel oxide layer is magnetron sputtered on the silver film, preferably with a thickness of 50 nm to 300 nm.

[0111] Of course, the aforementioned silver film can also be prepared using methods known in the industry, such as electron beam evaporation, ion plating, and thermal evaporation. The aforementioned nickel oxide layer can also be prepared using methods known in the industry, such as electron beam evaporation, thermal evaporation, and electrochemical deposition.

[0112] See Figure 12 As shown, by controlling the thickness of the nickel oxide layer, different colored dielectric layers can be obtained, which appear as colored films.

[0113] Referring to Example 1, after assembling a working electrode that is initially yellow with a counter electrode and a propylene carbonate electrolyte of LiPF6 to form a multicolor electrochromic device, when a voltage of -3V to +3V is applied between the working electrode and the counter electrode, the color of the working electrode will change in real time between yellow, orange, and orange-red.

[0114] Example 4: This example discloses a multi-color electrochromic device including a working electrode, an electrolyte layer and a counter electrode, wherein the electrolyte layer is disposed between the working electrode and the counter electrode.

[0115] See Figure 13 As shown, the working electrode includes a metal reflective layer, a dielectric layer, and an optimization layer disposed on a substrate. The metal reflective layer is formed of tungsten, the dielectric layer is formed of tungsten oxide, and the optimization layer is composed of silver. The substrate can be a PET plastic sheet, etc.

[0116] The working electrode is prepared as follows: On a clean PET plastic plate, a tungsten film is first magnetron sputtered, preferably with a thickness of about 100 nm. Then, a tungsten oxide layer is magnetron sputtered onto the tungsten film, preferably with a thickness of 150 nm to 400 nm. Finally, a silver layer is magnetron sputtered onto the tungsten oxide layer, preferably with a thickness of 1 nm to 15 nm.

[0117] Of course, the aforementioned tungsten film can also be prepared using methods known in the industry, such as electron beam evaporation, ion plating, and thermal evaporation. The aforementioned tungsten oxide layer can be prepared using methods known in the industry, such as electron beam evaporation, thermal evaporation, and electrochemical deposition. The aforementioned silver layer can be prepared using methods known in the industry, such as electron beam evaporation, ion plating, thermal evaporation, and electrochemical deposition.

[0118] In this embodiment, by controlling the thickness of the silver layer, the color of the multicolor electrochromic device can be further optimized compared to Embodiment 1. See also... Figure 14 The image shows the color display of the working electrode at different voltages (-3V to +3V) when a multicolor electrochromic device is assembled from working electrode samples with different tungsten oxide thicknesses (150nm to 250nm) having an Ag-optimized layer (Ag thickness of about 5nm), a counter electrode, and an electrolyte, and is powered on.

[0119] Example 5: This example discloses a multi-color electrochromic device including a working electrode and a counter electrode. The working electrode may consist of a metal reflective layer and a dielectric layer formed on a PET plastic sheet, wherein the metal reflective layer may be formed of a gold film with a thickness of 100 nm, and the dielectric layer may be formed of polydiyne with a thickness of 50 nm.

[0120] The working electrode is prepared as follows: On a clean PET plastic plate, a gold film is first deposited by physical vapor deposition, and then polydiyne is deposited on the gold film by thermal evaporation to form a dielectric layer.

[0121] When the power is off, the working electrode of this multi-color electrochromic device is red, and when a power supply of -5V to +5V is applied, the color changes between red, yellow and green.

[0122] Example 6: The structure of the multi-color electrochromic device in this example is basically the same as that in Example 4, but the silver layer, which serves as the optimization layer, is replaced by a ZnS layer. The thickness can be adjusted within a range greater than 0 and less than or equal to 300 nm, preferably 1 to 100 nm. When the multi-color electrochromic device in this example is not powered, it displays a single color. However, when the power is applied, its color can change between multiple colors depending on the voltage.

[0123] Example 7: The multi-color electrochromic device in this example is an all-solid-state structure, which also includes a working electrode, an electrolyte, and a counter electrode. The structure of this device can be found in [reference needed]. Figure 15 As shown in the diagram. The metal reflective layer is made of metal W, the dielectric layer is made of WO3, the ion-conducting layer (dielectric layer) is made of LiNbO3, the ion storage layer is made of NiO, and the counter electrode is made of ITO. The thickness of the metal reflective layer W is 500 nm, the thickness of the dielectric layer WO3 is 163 nm, the thickness of the ion-conducting layer LiNbO3 is 600 nm, the thickness of the ion storage layer NiO is 200 nm, and the thickness of the counter electrode ITO is 200 nm.

[0124] The inorganic all-solid-state multicolor electrochromic device of this embodiment presents a single color when not powered on, but its color can switch between multiple colors as the voltage changes after the power is turned on.

[0125] Example 8: The structure of the inorganic all-solid-state multicolor electrochromic device in this example can also be found in [reference needed]. Figure 15 Its metal reflective layer is made of Cr metal with a thickness of 50 nm, the dielectric layer is made of polythiophene with a thickness of 100 nm, the ion-conducting layer is made of LiAlF4 with a thickness of 400 nm, the ion storage layer is made of Fe2O3 with a thickness of 100 nm, and the counter electrode is made of transparent carbon nanotube film with a thickness of 20 nm.

[0126] Example 9: The structure of the inorganic all-solid-state multicolor electrochromic device in this example can also be found in [reference needed]. Figure 15Its metal layer is made of metal W with a thickness of 100nm, the electrochromic layer is made of Prussian blue with a thickness of 100nm, the ion-conducting layer is made of Li2O-B2O3 with a thickness of 100nm, the ion storage layer is made of TiO2 with a thickness of 100nm, and the conductive layer is made of AZO with a thickness of 80nm.

[0127] Example 10: The structure of the inorganic all-solid-state multicolor electrochromic device in this example can also be found in [reference needed]. Figure 15 The device employs a 100nm thick metal W layer, a 200nm thick tungsten trioxide electrochromic layer, a mixed ionic electrolyte of LiCl and ZnCl2, a 100nm thick TiO2 ion storage layer, and a 200nm thick ITO conductive layer. The use of a mixed ion electrolyte in this embodiment, compared to using a single ion, allows for richer color variations and higher color saturation in the electrochromic device.

[0128] In addition, the inventors of this application also conducted experiments using other electrochromic materials, metallic reflective materials, substrate materials, etc. listed in this specification to replace the corresponding materials in the aforementioned embodiments, and found that the obtained multicolor electrochromic structures and devices all have similar advantages.

[0129] The multicolor electrochromic device provided in this invention can achieve the fusion of structural color and electrochromism, displaying a rich variety of color changes, laying a solid foundation for the application of multicolor electrochromism and having broad prospects.

[0130] It should be understood that the above embodiments are merely illustrative of the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A multi-color electrochromic structure, comprising a working electrode, an electrolyte, and a counter electrode, wherein the electrolyte is distributed between the working electrode and the counter electrode, and the working electrode includes an electrochromic layer; characterized in that: The electrochromic layer includes a first reflective surface and a second reflective surface that are opposite to each other and arranged in parallel. A dielectric layer is disposed between the first reflective surface and the second reflective surface. The dielectric layer is composed of an electrochromic material and is disposed on a metal reflective layer. The first reflective surface is the first surface of the dielectric layer, and the second reflective surface is the interface between the second surface of the dielectric layer and the metal reflective layer. The first surface and the second surface are arranged opposite to each other. The first reflecting surface, the second reflecting surface, and the dielectric layer form an optical cavity, and when incident light enters the optical cavity, the phase shifts of the reflected light formed on the first reflecting surface and the reflected light formed on the second reflecting surface are as follows: Where d is the thickness of the dielectric layer. Let λ be the refractive index of the dielectric layer, and λ be the wavelength of the incident light. The angle of refraction of the incident light as it passes through the first reflecting surface is denoted as ...

2. The multicolor electrochromic structure according to claim 1, characterized in that, The reflection coefficient of the first reflecting surface is: The reflection coefficient of the second reflecting surface is: in, Let be the angle of incidence of the incident light. The angle of refraction is the angle at which the incident light passes through the second reflecting surface. The refractive index of the medium material on the first surface of the medium layer is given by [reference to a specific material]. is the refractive index of the medium material on the second surface of the medium layer.

3. The multicolor electrochromic structure according to claim 1, characterized in that, The reflectance coefficient of the electrochromic layer is: The reflectance of the electrochromic layer is:

4. The multicolor electrochromic structure according to claim 1, characterized in that, The thickness of the dielectric layer is greater than 0 and less than or equal to 0 to 3000 nm.

5. The multicolor electrochromic structure according to claim 4, characterized in that, The thickness of the dielectric layer is 100–500 nm.

6. The multicolor electrochromic structure according to claim 1, characterized in that, The thickness of the metal reflective layer is above 20 nm.

7. The multicolor electrochromic structure according to claim 6, characterized in that, The thickness of the metal reflective layer is 50–3000 nm.

8. The multicolor electrochromic structure according to claim 1, characterized in that, The electrochromic material includes oxides of Co, Rh, Ir, Ni, Cr, Mn, Fe, Ti, V, Nb, Ta, Mo, or W.

9. The multicolor electrochromic structure according to claim 1, characterized in that, The electrochromic material includes any one or more combinations of Prussian blue or its derivatives, and heteropolyacids.

10. The multicolor electrochromic structure according to claim 1, characterized in that, The electrochromic material is selected from any one or more combinations of small organic molecules, organic polymers, and organometallic compounds.

11. The multicolor electrochromic structure according to claim 10, characterized in that, The organic small molecules include methyl violarin or violarin.

12. The multicolor electrochromic structure according to claim 10, characterized in that, The organic polymer includes any one or more combinations of polydiyne, polyaniline, polythiophene, and polypyrrole.

13. The multicolor electrochromic structure according to claim 10, characterized in that, The organometallic compounds include organometallic chelates.

14. The multicolor electrochromic structure according to claim 1, characterized in that, The material of the metal reflective layer includes non-reactive metals.

15. The multicolor electrochromic structure according to claim 14, characterized in that, The inert metals include gold, silver, copper, tungsten, or titanium.

16. The multicolor electrochromic structure according to claim 1, characterized in that, The working electrode also includes a substrate, and the electrochromic layer is disposed on the substrate.

17. The multicolor electrochromic structure according to claim 16, characterized in that, The substrate can be made of glass, plexiglass, plastic sheet, wood, or metal.

18. The multicolor electrochromic structure according to claim 1, characterized in that, The electrolyte includes liquid electrolytes, gel electrolytes, or solid electrolytes.

19. The multicolor electrochromic structure according to claim 18, characterized in that, The electrolyte used is a solid electrolyte.

20. The multicolor electrochromic structure according to claim 1, characterized in that, The multi-color electrochromic structure is an all-solid-state structure.

21. The multicolor electrochromic structure according to claim 1, characterized in that, The counter electrode includes a transparent conductive electrode.

22. The multicolor electrochromic structure according to claim 21, characterized in that, An ion storage layer is also provided between the transparent conductive electrode and the dielectric layer.

23. The multicolor electrochromic structure according to claim 1, characterized in that, The metal reflective layer also serves as a current collector for the electrochromic layer.

24. The method for controlling the multicolor electrochromic structure as described in any one of claims 1-23, characterized in that... include: Connect the working electrode and the counter electrode to the power supply to form a working circuit. The potential difference between the working electrode and the counter electrode is adjusted to at least change the refractive index of the electrochromic material in the dielectric layer, thereby controlling the color of the multicolor electrochromic structure.

25. An electrochromic device, characterized in that... It includes the multicolor electrochromic structure described in any one of claims 1-23.

26. The electrochromic device according to claim 25, characterized in that, The electrochromic device is an all-solid-state structure.

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