Electrochromic device and method of making the same

Abstract

This invention discloses an electrochromic device and its fabrication method. The electrochromic device includes an electrochromic layer and a first electrode layer and a second electrode layer acting on two opposite surfaces of the electrochromic layer. The electrochromic layer is made of viologen, and the first electrode layer and / or the second electrode layer contains a transition metal material selected from one or more of nickel, copper, silver, palladium, zinc, molybdenum, niobium, and palladium. This invention uses a transparent conductive film based on a transition metal (such as nickel or palladium) that readily donates electrons, greatly increasing the duration of the colored state without affecting the conductivity, thus achieving large-area, uniform, and rapid color change.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of electronic device component preparation, and in particular to an electrochromic device and a method for manufacturing the same. BACKGROUND

[0002] Electrochromism refers to a phenomenon that when an external voltage is applied to an electrochromic material, the material itself will undergo an oxidation-reduction reaction and reversibly change its color, spectral transmittance and reflectance. Due to the low energy consumption, low driving voltage, the ability to maintain the display state without voltage and rich color of the electrochromic device, the electrochromic device has a very good application prospect in the fields of smart windows, automobile rearview mirrors, displays and the like. The light modulation property of the electrochromic device plays a very important role in building energy saving. For example, in summer, the absorption of infrared rays by the smart window can be changed to reduce the increase of indoor temperature and reduce the energy consumption of air conditioning. At the same time, due to the blocking of the visible light region by the color change, the situation of opening the curtains and turning on the light can be replaced, thereby reducing the light intensity entering the room and further reducing the building energy consumption.

[0003] All-in-one electrochromic devices have attracted extensive attention due to their simple preparation and potential low-cost preparation advantages. For example, the porthole of Boeing 787 adopts an all-in-one electrochromic device structure. The electrochromic material of the all-in-one electrochromic device mainly adopts a viologen compound. The biggest problem of the viologen compound is that the time for maintaining the color is short, mostly within 30 minutes, and a continuous voltage needs to be provided to maintain the colored state.

[0004] The information disclosed in this BACKGROUND section is only for the purpose of increasing the understanding of the background of the present application and should not be regarded as an acknowledgment or any form of suggestion that this information forms prior art that is publicly known. SUMMARY

[0005] The present application aims to provide an electrochromic device and a method for manufacturing the same, which can overcome the technical problem of short time for maintaining the color in the prior art.

[0006] To achieve the above-mentioned purpose, an embodiment of the present application provides an electrochromic device, comprising an electrochromic layer and a first electrode layer and a second electrode layer respectively acting on opposite two surfaces of the electrochromic layer,

[0007] The material of the electrochromic layer comprises a viologen,

[0008] The material of the first electrode layer and / or the second electrode layer contains a transition metal material, and the transition metal material is selected from one or more of nickel, copper, silver, palladium, zinc, molybdenum, niobium and palladium.

[0009] In one or more embodiments of the present application, the first electrode layer and / or the second electrode layer comprises:

[0010] a conductive electrode layer;

[0011] a transition metal electrode layer formed between the conductive electrode layer and the electrochromic layer, the material of the transition metal electrode layer comprising the transition metal material.

[0012] In one or more embodiments of the present application, the material of the conductive electrode layer is selected from one or more of nickel, copper, silver, palladium, zinc, molybdenum, niobium, palladium.

[0013] In one or more embodiments of the present application, the conductive electrode layer employs a metal mesh electrode, and / or

[0014] the transition metal electrode layer employs a metal mesh electrode.

[0015] In one or more embodiments of the present application, the electrochromic layer simultaneously functions as an electrolyte layer and an ion storage layer.

[0016] To achieve the above object, an embodiment of the present application further provides a method for manufacturing an electrochromic device, comprising:

[0017] providing a first electrode layer and a second electrode layer, the material of the first electrode layer and / or the second electrode layer comprising a transition metal material selected from one or more of nickel, copper, silver, palladium, zinc, molybdenum, niobium, palladium;

[0018] preparing an electrochromic paste containing a viologen;

[0019] curing the electrochromic paste between the first electrode layer and the second electrode layer to form an electrochromic layer.

[0020] In one or more embodiments of the present application, the first electrode layer and / or the second electrode layer comprises:

[0021] a conductive electrode layer;

[0022] a transition metal electrode layer formed between the conductive electrode layer and the electrochromic layer, the material of the transition metal electrode layer comprising the transition metal material.

[0023] In one or more embodiments of the present application, the material of the conductive electrode layer is selected from one or more of nickel, copper, silver, palladium, zinc, molybdenum, niobium, palladium.

[0024] In one or more embodiments of the present application, the step of providing a first electrode layer and a second electrode layer comprises:

[0025] a first conductive electrode layer and a first transition metal electrode layer are sequentially formed on a surface of the first substrate;

[0026] a second conductive electrode layer and a second transition metal electrode layer are sequentially formed on a surface of the second substrate,

[0027] The step of curing the electrochromic paste between the first electrode layer and the second electrode layer comprises:

[0028] The electrochromic paste is cured between the first transition metal electrode layer and the second transition metal electrode layer.

[0029] In one or more embodiments of the present application, the electrochromic layer simultaneously serves as an electrolyte layer and an ion storage layer.

[0030] Compared with the prior art, the present application uses a transition metal-based (such as nickel, palladium) transparent conductive film that easily donates electrons, greatly increases the maintenance time of the colored state without affecting the electrical conductivity, and realizes large-area uniform and rapid color change. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 is a structural schematic diagram of an electrochromic device according to an embodiment of the present application;

[0032] Figure 2 is a flowchart of the manufacturing process of an electrochromic device according to an embodiment of the present application;

[0033] Figure 3a and Figure 3b is an intermediate structural schematic diagram of the manufacturing process of an electrochromic device according to an embodiment of the present application. DETAILED DESCRIPTION

[0034] The specific embodiments of the present application will be described in detail below with reference to the accompanying drawings, but it should be understood that the scope of protection of the present application is not limited by the specific embodiments.

[0035] Unless otherwise explicitly indicated, throughout the specification and claims, the term "comprise" or its variants such as "comprises" or "comprising" will be understood to encompass the stated elements or components, without excluding the presence of other elements or components.

[0036] As shown in Figure 1 An electrochromic device 10 according to a preferred embodiment of the present application includes an electrochromic layer 11 and first and second electrode layers 12 and 13 respectively acting on the opposite two surfaces of the electrochromic layer 11.

[0037] The first electrode layer 12 serves as a working electrode, and the second electrode layer 13 serves as a counter electrode. After being powered on, an electric field can be formed between the first electrode layer 12 and the second electrode layer 13, so that the electrochromic layer 11 can change color.

[0038] The electrochromic layer 11 adopts a multi-in-one electrochromic layer, which means that the electrochromic layer 11 simultaneously has the functions of an electrochromic layer, an electrolyte layer, and an ion storage layer.

[0039] The electrochromic layer 11 adopts a composite structure of a polymer binder and an electrochromic material.

[0040] The polymer binder serves as the skeleton of the electrolyte, such as polyvinyl butyral (PVB), polymethyl methacrylate (PMMA), polyvinylidene fluoride (PVDF), polyethylene oxide (PEO, PEG), etc.

[0041] The electrochromic material refers to a material that, under the action of current or an electric field, undergoes light absorption or light scattering, thereby causing a stable and reversible change in color. In this embodiment, the electrochromic material is a viologen and its homologues.

[0042] Under normal circumstances, the viologen becomes colored by receiving electrons, and after the voltage is removed, the viologen loses electrons and becomes transparent.

[0043] In order to enable the electrochromic layer 11 to simultaneously have the functions of an ion storage layer and an electrolyte layer, the material of the electrochromic layer 11 also contains an ion storage material, a salt, and a solvent. The ion storage material is mainly ferrocene, etc.; the salt is mainly lithium salt, such as LiTFSI, lithium perchlorate, etc.; and the solvent is propylene carbonate, etc.

[0044] The material of the multi-in-one electrochromic layer adopts a viologen compound, and the biggest problem is that the colored state cannot be maintained for a long time, and a continuous voltage needs to be provided to maintain the colored state.

[0045] In order to overcome the above problems, this embodiment uses a transition metal that is easy to give electrons as the material of the first electrode layer 12 or the second electrode layer 13. In a preferred embodiment, the material of the transition metal that is easy to give electrons includes nickel, or palladium, or a combination of nickel and palladium.

[0046] This embodiment takes full advantage of the characteristics that the viologen becomes colored by receiving electrons, and after the voltage is removed, the transition metal can give electrons to keep the entire system in the colored state, thereby prolonging the colored time.

[0047] In an embodiment, the first electrode layer 12 includes a first conductive electrode layer 121 and a first transition metal electrode layer 122, and the first transition metal electrode layer 122 is formed between the electrochromic layer 11 and the first conductive electrode layer 121.

[0048] The first conductive electrode layer 121 is used to provide good conductivity, and uses a material with high light transmittance, low sheet resistance, etc. The material can include one or more of the following: 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 (zinc oxide), OMO (oxide / metal / oxide), and transparent conductive oxides of CTO, silver (Ag) nanowires, metal mesh, or OMO (oxide metal oxide), etc.

[0049] One challenge in the industrial application of electrochromic devices is large-area preparation, and the main problem is the preparation of large-area electrodes. For example, traditional electrochromic devices use ITO as the electrode, but the high cost, long preparation time (using sputtering method), and large resistance restrict the preparation and application of large-area electrochromic devices.

[0050] To overcome the above problems, in a preferred embodiment, the first conductive electrode layer 121 uses a metal mesh electrode, and the material of the metal mesh electrode can use nickel, copper, silver, palladium, zinc, molybdenum, niobium, or palladium, or a combination thereof, etc. The light transmittance of the metal mesh transparent electrode is 50%-90%, and the sheet resistance of the metal mesh transparent electrode is 0.05-20 Ω / □.

[0051] The first transition metal electrode layer 122 is a metal mesh electrode, and uses a transition metal material, such as one or more of nickel, copper, silver, palladium, zinc, molybdenum, niobium, or palladium. In this case, the metal mesh electrode can have good conductivity, and the properties of nickel, palladium, and other transition metals can be used to maintain a certain coloring time, avoiding the need for constant voltage to maintain the colored state, reducing energy consumption and extending the life of the device.

[0052] This embodiment makes full use of the aspect ratio of the metal mesh structure, ensuring high conductivity while maintaining high transmittance, allowing for easy production of large-area devices, and the electrochromic area can be greater than or equal to 10 cm*10 cm.

[0053] In other embodiments, when the first transition metal electrode layer 122 can ensure good conductivity, the first conductive electrode layer 121 structure can also be omitted. That is, the first electrode layer 12 can be a metal mesh electrode that can provide electrons to the electrochromic layer 11.

[0054] In one embodiment, the second electrode layer 13 includes a second conductive electrode layer 131 and a second transition metal electrode layer 132, and the second transition metal electrode layer 132 is formed between the electrochromic layer 11 and the second conductive electrode layer 131.

[0055] The second conductive electrode layer 131 is used to provide good conductivity, and uses a material with high light transmittance, low sheet resistance, etc. It can include one or more of the following materials: 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 (zinc oxide), OMO (oxide / metal / oxide), and transparent conductive oxides of CTO, silver (Ag) nanowires, metal mesh, or OMO (oxide metal oxide), etc.

[0056] In a preferred embodiment, the second conductive electrode layer 131 uses a metal mesh electrode, and the material of the metal mesh electrode can use nickel, copper, silver, palladium, zinc, molybdenum, niobium, or palladium, or a combination thereof. The metal mesh transparent electrode has a light transmittance of 50%-90% and a sheet resistance of 0.05-20 Ω / □.

[0057] The second transition metal electrode layer 132 is a metal mesh electrode, and uses a transition metal material, such as one or more of nickel, copper, silver, palladium, zinc, molybdenum, niobium, or palladium. In this case, the metal mesh electrode can have good conductivity, and the use of transition metals such as nickel and palladium can maintain a certain coloring time, avoiding the need for constant voltage to maintain the colored state, reducing energy consumption and prolonging the life of the device.

[0058] This embodiment makes full use of the aspect ratio of the metal mesh structure to ensure high conductivity while maintaining high transmittance, making it easy to make large-area devices. The electrochromic area can be greater than or equal to 10 cm*10 cm.

[0059] In other embodiments, when the second transition metal electrode layer 132 can ensure good conductivity, the second conductive electrode layer 131 structure can also be omitted. That is, the second electrode layer 13 can be a metal mesh electrode that can provide electrons to the electrochromic layer 11.

[0060] It should be noted that the first electrode layer 12 and the second electrode layer 13 can also be selectively selected from transition metal materials, such as the first electrode layer 12 containing nickel, palladium, and other transition metals, and the second electrode layer 13 directly using ITO and other materials.

[0061] By changing the thickness of the first electrode layer 12 and the second electrode layer 13 and the type of transition metal material, the color change and maintenance time of the device can be controlled.

[0062] The electrochromic device 10 further comprises a first substrate 14 and a second substrate 15. The first substrate 14, the first electrode layer 12, the electrochromic layer 11, the second electrode layer 13 and the second substrate 15 are sequentially stacked.

[0063] The first substrate 14 and the second substrate 15 are made of transparent material, and are used for supporting the first electrode layer 12 and the second electrode layer 13 and as protective cover plate. The transparent material has a light transmittance greater than 70%, and is preferably glass or resin (such as PEN, PET, etc.). When the material is glass, the device can be applied to building window glass, automobile window glass, etc.

[0064] In specific embodiments, the glass can be, for example, alkali-free glass, borosilicate glass, soda-lime glass, etc. The resin can be, for example, polycarbonate resin, acrylic resin, epoxy resin, phenolic resin, etc.

[0065] In other embodiments, the first substrate 14 and the second substrate 15 can also be made of metal, such as aluminum, stainless steel, etc.

[0066] In combination Figure 2 As shown, the present embodiment also provides a method for manufacturing an electrochromic device, comprising the following steps.

[0067] In combination Figure 3a As shown, a first substrate 14 is provided, and a first conductive electrode layer 121 and a first transition metal electrode layer 122 are sequentially formed on the first substrate 14.

[0068] The first substrate 14 is made of transparent material, and has a light transmittance greater than 70%, and is preferably glass or resin. When the material is glass, the device can be applied to building window glass, automobile window glass, etc.

[0069] In specific embodiments, the glass can be, for example, alkali-free glass, borosilicate glass, soda-lime glass, etc. The resin can be, for example, polycarbonate resin, acrylic resin, epoxy resin, phenolic resin, etc.

[0070] In other embodiments, the first substrate 14 can also be made of metal, such as aluminum, stainless steel, etc.

[0071] The first conductive electrode layer 121 is used to provide good conductivity, and adopts a material with high light transmittance, low sheet resistance, etc. It can include one or more of the following materials: 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 (zinc oxide), OMO (oxide / metal / oxide), and transparent conductive oxides of CTO, silver (Ag) nanowires, metal mesh, or OMO (oxide metal oxide), etc.

[0072] In a preferred embodiment, the first conductive electrode layer 121 adopts a metal mesh electrode, and the material of the metal mesh electrode can adopt nickel, copper, silver, palladium, zinc, molybdenum, niobium, or palladium, or a combination thereof. The light transmittance of the metal mesh transparent electrode is 50%-90%, and the sheet resistance of the metal mesh transparent electrode is 0.05-20 Ω / □.

[0073] The first conductive electrode layer 121 can be prepared by methods such as blade coating, electroplating, etc.

[0074] The first transition metal electrode layer 122 is a metal mesh electrode, and adopts a transition metal material, such as one or more of nickel, copper, silver, palladium, zinc, molybdenum, niobium, or palladium. In this case, the metal mesh electrode can have good conductivity, and the characteristics of nickel, palladium, etc. can be used to maintain a certain coloring time, avoiding the need for constant voltage to maintain the colored state, reducing energy consumption and prolonging the service life of the device.

[0075] The first transition metal electrode layer 122 can be prepared by methods such as blade coating, electroplating, etc.

[0076] Step s2, combining Figure 3b As shown, a second substrate 15 is provided, and a second conductive electrode layer 131 and a second transition metal electrode layer 132 are sequentially formed on the second substrate 15.

[0077] The second substrate 15 adopts a transparent material, and the light transmittance should be greater than 70%, and is preferably glass or resin. When it is glass, the device can be applied to building window glass, automobile window glass, etc.

[0078] In specific embodiments, the glass can adopt, for example, alkali-free glass, borosilicate glass, soda-lime glass, etc. The resin can adopt, for example, polycarbonate resin, acrylic resin, epoxy resin, phenolic resin, etc.

[0079] In other embodiments, the second substrate 15 can also adopt a metal such as aluminum, stainless steel, etc.

[0080] In a preferred embodiment, the second substrate 15 and the first substrate 14 adopt the same material.

[0081] The second conductive electrode layer 131 is used to provide good conductivity, and adopts a material with high light transmittance, low sheet resistance, etc. It can include one or more of the following materials: 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 (zinc oxide), OMO (oxide / metal / oxide), and transparent conductive oxides of CTO, silver (Ag) nanowires, metal mesh, or OMO (oxide metal oxide), etc.

[0082] In a preferred embodiment, the second conductive electrode layer 131 adopts a metal mesh electrode, and the material of the metal mesh electrode can adopt nickel, copper, silver, palladium, zinc, molybdenum, niobium, or palladium, or a combination thereof, etc. The light transmittance of the metal mesh transparent electrode is 50%-90%, and the sheet resistance of the metal mesh transparent electrode is 0.05-20 Ω / □.

[0083] The second conductive electrode layer 131 can be prepared by methods such as blade coating and electroplating.

[0084] The second transition metal electrode layer 132 is a metal mesh electrode, and adopts one or more of transition metal materials such as nickel, copper, silver, palladium, zinc, molybdenum, niobium, or palladium. In this case, the metal mesh electrode can not only have good conductivity, but also can maintain a certain coloring time by using the characteristics of transition metals such as nickel and palladium, avoiding the need for constant voltage to maintain the colored state, reducing energy consumption and prolonging the service life of the device.

[0085] The second transition metal electrode layer 132 can be prepared by methods such as blade coating and electroplating.

[0086] Step s3: preparing a multi-in-one electrochromic paste including an electrochromic material, a polymer binder, an ion storage material, a salt, and a solvent, so that the electrochromic layer 11 has the functions of an electrochromic layer, an electrolyte layer, and an ion storage layer at the same time.

[0087] The polymer binder serves as the skeleton of the electrolyte, such as polyvinyl butyral (PVB), polymethyl methacrylate (PMMA), polyvinylidene fluoride (PVDF), polyethylene oxide (PEO, PEG), etc.

[0088] The electrochromic material refers to a material that undergoes light absorption or light scattering under the action of current or electric field, thereby causing a stable and reversible change in color. In this embodiment, the electrochromic material is a viologen and its homologues.

[0089] The ion storage material is mainly ferrocene, and the salt is mainly lithium salt such as LiTFSI, lithium perchlorate, etc., and the solvent is propylene carbonate, etc.

[0090] Step s4, combining Figure 1 The all-in-one electrochromic paste is placed between the first transition metal electrode layer 122 and the second transition metal electrode layer 132, the thickness of the device is regulated by double-sided adhesive or microspheres, generally 30-200 microns, and the device is packaged by using ultraviolet curing glue, and the device preparation is completed.

[0091] The all-in-one electrochromic paste of ethyl viologen is prepared, LiTFSI is used as the Li salt, propylene carbonate is used as the solvent, and polyvinyl butyral is used as the connecting material, the performance of the obtained device is compared and shown in Table 1 by changing the electrode material and structure.

[0092] Table 1

[0093]

[0094]

[0095] As shown in Table 1, when the electrode is made of transition metal material, the performance of the device based on viologen electrochromic layer can be greatly improved: the coloration state transmittance is 5-20%, the bleaching state transmittance is 70-90%, the color change time is 0.5-8s, and the coloration state maintenance time is more than 3h, especially when the electrode layer is made of composite electrode and the transition metal material is selected from nickel or palladium, the coloration state maintenance time is more than 8h.

[0096] The foregoing description of specific exemplary embodiments of the application is intended to be illustrative only and is not intended to limit the application to the precise forms described. Many modifications and variations are possible in light of the above teachings without departing from the spirit or essential characteristics of the application. The exemplary embodiments were chosen and described in order to explain the principles of the application and its practical application and to allow others skilled in the art to understand the application for various exemplary embodiments with various modifications being suited to the particular use contemplated. The scope of the application is intended to be defined by the claims and their equivalents.

Claims

1. An electrochromic device, characterized in that, comprising an electrochromic layer and a first electrode layer and a second electrode layer respectively acting on opposite surfaces of the electrochromic layer, a material of the electrochromic layer comprises a viologen, the first electrode layer comprises a first conductive electrode layer and a first transition metal electrode layer, the first transition metal electrode layer being formed between the electrochromic layer and the first conductive electrode layer, the second electrode layer comprises a second conductive electrode layer and a second transition metal electrode layer, the second transition metal electrode layer being formed between the electrochromic layer and the second conductive electrode layer, a material of the first conductive electrode layer is silver, a material of the second conductive electrode layer is silver, a material of the first transition metal electrode layer is selected from nickel, palladium, copper, zinc, molybdenum or niobium, a material of the second transition metal electrode layer is selected from nickel, palladium, copper, zinc, molybdenum or niobium, the first conductive electrode layer and the second conductive electrode layer adopt a metal mesh electrode, and the first transition metal electrode layer and the second transition metal electrode layer adopt a metal mesh electrode.

2. The electrochromic device of claim 1, wherein, the electrochromic layer simultaneously serves as an electrolyte layer and an ion storage layer.

3. A method of fabricating an electrochromic device, the method comprising: comprising: providing a first electrode layer and a second electrode layer, the first electrode layer comprising a first conductive electrode layer and a first transition metal electrode layer, the first transition metal electrode layer being formed between the electrochromic layer and the first conductive electrode layer, the second electrode layer comprising a second conductive electrode layer and a second transition metal electrode layer, the second transition metal electrode layer being formed between the electrochromic layer and the second conductive electrode layer, a material of the first conductive electrode layer and the second conductive electrode layer being silver, a material of the first transition metal electrode layer and the second transition metal electrode layer being selected from one of nickel, palladium, copper, zinc, molybdenum or niobium, the first conductive electrode layer and the second conductive electrode layer adopting a metal mesh electrode, and the first transition metal electrode layer and the second transition metal electrode layer adopting a metal mesh electrode; preparing an electrochromic slurry containing a viologen; curing the electrochromic slurry between the first electrode layer and the second electrode layer to form an electrochromic layer.

4. The method of producing an electrochromic device according to claim 3, wherein the step of providing a first electrode layer and a second electrode layer comprises: providing a first substrate, sequentially forming a first conductive electrode layer and a first transition metal electrode layer on a surface of the first substrate; providing a second substrate, sequentially forming a second conductive electrode layer and a second transition metal electrode layer on a surface of the second substrate, the step of curing the electrochromic slurry between the first electrode layer and the second electrode layer comprises: curing the electrochromic slurry between the first transition metal electrode layer and the second transition metal electrode layer.

5. The method of producing an electrochromic device according to claim 3, wherein the electrochromic layer simultaneously serves as an electrolyte layer and an ion storage layer.

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