KR102170911B1 - Manufacturing method of electrochromic device and electrochromic device thereby - Google Patents

Abstract

The present invention relates to a method of manufacturing an electrochromic device and an electrochromic device therefrom. The method of manufacturing an electrochromic device according to an embodiment of the present invention comprises: forming a tungsten thin film on a first transparent conductive oxide substrate. Forming; Oxidizing the tungsten thin film into a tungsten oxide thin film by applying an acidic solution on the tungsten thin film; And injecting and sealing an electrolyte between the tungsten oxide thin film and the second transparent conductive oxide substrate.

Description

TECHNICAL FIELD The manufacturing method of an electrochromic device and an electrochromic device by the method TECHNICAL FIELD [MANUFACTURING METHOD OF ELECTROCHROMIC DEVICE AND ELECTROCHROMIC DEVICE THEREBY}

The present invention relates to a method of manufacturing an electrochromic device and an electrochromic device thereby.

In general, electrochromism is a reaction in which ions and electrons enter and exit through electrochemical reduction reaction (anode reaction) and oxidation reaction (cathode reaction) when an external current is applied to a substance. It refers to a phenomenon in which the color of is reversibly changed, that is, when an electric field is applied, it becomes colored, and when an opposite electric field is applied, it becomes discolored.

These electrochromic reaction phenomena are used to manufacture display devices, display devices for use in electronic paper, smart glasses, and the like, and electrochromic materials include vanadium pentaoxide, cobalt oxide, tungsten oxide, tungsten molybdenum oxide, and fluorine. Ride glasses and the like are mainly used. Such an electrochromic material has a characteristic of changing color by an applied voltage, and electrochromic materials return to their original color when the applied voltage disappears or the polarity is reversed.

Tungsten oxide (WO ₃ ) is the most widely used electrochromic material so far. Tungsten oxide has high ion mobility, absorbs light in the visible region and is colored blue. Electrochromic thin films such as tungsten oxide undergo a reversible color change by application of an electric field or current.

The formation of a tungsten oxide thin film is prepared by liquid application and sputtering. Liquid application is a method in which tungsten powder is oxidized in a liquid state to form a sol, and it is difficult to use fine tungsten powder, and a process time for making a sol is required. In addition, sputtering using a tungsten oxide target requires the use of RF voltage because tungsten oxide is a ceramic, and since sputtering does not occur smoothly, a suitable manufacturing process method is required in terms of productivity and mass production to form the required thickness.

Accordingly, as a technology for securing productivity and mass production, the process conditions are optimized when forming a tungsten oxide layer in electrochromic device manufacturing to shorten the process time, control response speed, coloring efficiency, light transmittance, and charge density. There is a need for a method of manufacturing an excellent electrochromic device.

The present invention is to solve the above problems, and an object of the present invention is to provide a method of manufacturing an electrochromic device capable of reducing time and manufacturing cost by simplifying the process method and improving productivity and mass production problems. Is to do.

Another object of the present invention is to provide an electrochromic device having a fast response speed, linear light transmittance control through discoloration, and excellent durability and lifespan.

However, the problems to be solved by the present invention are not limited to those mentioned above, and other problems that are not mentioned will be clearly understood by those skilled in the art from the following description.

An aspect of the present invention, forming a tungsten thin film on a first transparent conductive oxide substrate; Oxidizing the tungsten thin film into a tungsten oxide thin film by applying an acidic solution on the tungsten thin film; Injecting and sealing an electrolyte between the tungsten oxide thin film and the second transparent conductive oxide substrate is provided, including a method of manufacturing an electrochromic device.

In one embodiment, the method of forming the tungsten thin film includes a sputtering method, an atomic layer deposition (ALD) method, and a plasma enhanced amotic layer deposition (PE-ALD) method. , Chemical Vapor Deposition (CVD) method, Plasma-Enhanced Chamical Vapor Deposition (PE-CVD) method, Pulsed Laser Deposition (PLD) method, and molecular beam epitaxy (Molecular At least one selected from the group consisting of Beam Epitaxy (MBE) method is included, and the tungsten thin film may be formed to have a thickness of 140 nm to 170 nm.

In one embodiment, the acidic solution may include at least one selected from the group consisting of hydrogen peroxide, nitric acid, hydrochloric acid, sulfuric acid, and hydrofluoric acid, and the concentration of the acidic solution may be 20% to 40%.

In one embodiment, after the step of oxidizing the tungsten thin film into a tungsten oxide thin film by applying an acidic solution on the tungsten thin film, removing impurities formed on the tungsten oxide thin film; further comprising, the tungsten oxide The step of removing the impurities formed on the thin film may include washing the first transparent conductive oxide substrate including the tungsten oxide thin film with distilled water; Removing the distilled water using an air knife; And drying in a drying furnace to evaporate the residue; may include.

Another aspect of the present invention is manufactured by the method of manufacturing an electrochromic device according to an aspect of the present invention, and has a light transmittance of 80% or more when an electric field is applied, and a light transmittance of 5% to 30% when an electric field is removed. , It provides an electrochromic device in which the driving voltage is 1 V to 3 V, and the response speed is within 60 seconds.

The electrochromic device is driven by a low voltage according to the manufacturing method of an electrochromic device according to an embodiment of the present invention, and has a fast response speed within 60 seconds and a linear light transmittance control through discoloration, and has excellent durability and lifespan. The device can be manufactured.

The conventional electrochromic device manufacturing method is manufactured through a high cost and complex process method, but the introduction of a wet oxidation treatment method different from the existing method reduces manufacturing cost and reduces the time by simplifying the process method, and productivity and mass production problems Can be improved.

The electrochromic device of the present invention may be driven by a device even at a low voltage, and may have a fast response speed and linear light transmittance control through discoloration, and excellent durability and longevity.

1 is a flowchart illustrating a method of manufacturing an electrochromic device according to an embodiment of the present invention.
2 is a cross-sectional view of an electrochromic device according to an embodiment of the present invention.
3 is a photograph of impurities formed after applying a hydrogen peroxide solution on a tungsten thin film according to an embodiment of the present invention.
4 is a photograph after impurities are removed after applying a hydrogen peroxide solution on a tungsten thin film according to an embodiment of the present invention.
5 is a photograph before applying a voltage of 5 V to the electrochromic device according to an embodiment of the present invention.
6 is a photograph after applying a voltage of 5 V to the electrochromic device according to an embodiment of the present invention.
7 is a light spectrum showing the intensity of light according to the concentration of lithium ions in the electrochromic device according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In describing the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, a detailed description thereof will be omitted. In addition, terms used in the present specification are terms used to properly express a preferred embodiment of the present invention, which may vary depending on the intention of users or operators, or customs in the field to which the present invention belongs. Accordingly, definitions of these terms should be made based on the contents throughout the present specification. The same reference numerals in each drawing indicate the same members.

Throughout the specification, when a member is said to be positioned "on" another member, this includes not only the case where a member is in contact with another member, but also the case where another member exists between the two members.

Throughout the specification, when a part "includes" a certain component, it means that other components may be further included rather than excluding other components.

Hereinafter, a method of manufacturing an electrochromic device and an electrochromic device according to the method of the present invention will be described in detail with reference to examples and drawings. However, the present invention is not limited to these examples and drawings.

An aspect of the present invention, forming a tungsten thin film on a first transparent conductive oxide substrate; Oxidizing the tungsten thin film into a tungsten oxide thin film by applying an acidic solution on the tungsten thin film; Injecting and sealing an electrolyte between the tungsten oxide thin film and the second transparent conductive oxide substrate is provided, including a method of manufacturing an electrochromic device.

1 is a flow chart showing a method of manufacturing an electrochromic device according to an embodiment of the present invention. Referring to FIG. 1, a method of manufacturing an electrochromic device according to an embodiment of the present invention includes a tungsten thin film forming step 110, an oxidation step 120 with a tungsten oxide thin film, and an electrolyte injection and sealing step 130. Include.

In one embodiment, the step of forming the tungsten thin film 110 may include forming a tungsten thin film on the first transparent conductive oxide substrate.

In one embodiment, the first transparent conductive oxide substrate may be formed of a first transparent conductive oxide on the first substrate.

In one embodiment, the first substrate is glass, alumina, SiO ₂ , polyethylene terephalate (PET), polyethylene naphthalate (PEN), polyethersulfonate (PES), and polycarbonate. It may contain at least one selected from the group consisting of (polycarbonate, PC).

In one embodiment, the first transparent conductive oxide is, indium tin oxide (ITO), indium zinc oxide (IZO), fluorine-doped tin oxide (FTO), Al-doped zinc oxide (AZO), Ga-doped It may include at least one selected from the group consisting of ZnO (GZO) and transparent conductive oxide (TCO). The transparent conductive oxide may be an electrode, the first transparent conductive oxide of the first transparent conductive oxide substrate may be a lower electrode, and the second transparent conductive oxide of the second transparent conductive oxide substrate may be an upper electrode. Alternatively, the first transparent conductive oxide of the first transparent conductive oxide substrate may be an upper electrode, and the second transparent conductive oxide of the second transparent conductive oxide substrate may be a lower electrode. The upper electrode and the lower electrode may have the same substrate and transparent conductive oxide, or may be different from each other.

In one embodiment, the method of forming the tungsten thin film includes a sputtering method, an atomic layer deposition (ALD) method, and a plasma enhanced amotic layer deposition (PE-ALD) method. , Chemical Vapor Deposition (CVD) method, Plasma-Enhanced Chamical Vapor Deposition (PE-CVD) method, Pulsed Laser Deposition (PLD) method, and molecular beam epitaxy (Molecular It may include at least one selected from the group consisting of Beam Epitaxy; MBE) method. Preferably, it may be to use a sputtering method.

In one embodiment, in the case of using the sputtering method, the target of the tungsten thin film may be a tungsten target close to ultrapure water having a purity of 100%.

In one embodiment, the tungsten thin film may be formed to a thickness of 140 nm to 170 nm. If the tungsten thin film is less than 140 nm, the electrochromic device is easily destroyed at a high voltage and the number of driving changes in decolorization and coloring, resulting in poor stability and durability.If it exceeds 170 nm, the sheet resistance of the electrochromic device increases and the transmittance is good. There is no problem.

In one embodiment, the oxidizing step 120 with the tungsten oxide thin film may be to oxidize the tungsten thin film into a tungsten oxide thin film by applying an acidic solution on the tungsten thin film.

In one embodiment, the acidic solution may include at least one selected from the group consisting of hydrogen peroxide, nitric acid, hydrochloric acid, sulfuric acid, and hydrofluoric acid.

In one embodiment, the acidic solution may be applied on the tungsten thin film by at least one method selected from the group consisting of drop casting, spin casting, spin coating, dip coating, spray coating, and flow coating. have.

In one embodiment, the concentration of the acidic solution may be 20% to 40%. If the concentration of the acidic solution is less than 20%, the reaction rate becomes more than several minutes, causing an increase in the process time, and if it exceeds 40%, the film quality is not flat.

In one embodiment, the applied acidic solution may react with the tungsten thin film at room temperature to form a ceramic tungsten oxide thin film. The tungsten oxide thin film may be slightly thicker than the tungsten thin film, but the difference may be insignificant.

In one embodiment, after the step of oxidizing the tungsten oxide thin film into a tungsten oxide thin film by applying an acidic solution on the tungsten thin film, removing impurities formed on the tungsten oxide thin film (not shown); further comprising: I can.

In one embodiment, the removing of the impurities formed on the tungsten oxide thin film includes: washing the first transparent conductive oxide substrate including the tungsten oxide thin film with distilled water (not shown); Removing the distilled water using an air knife (not shown); And drying in a drying furnace to evaporate the residue (not shown); may include. The residue may include distilled water, an acidic solution, a tungsten oxide thin film that has fallen off, and H ₂ O after the reaction.

In one embodiment, drying in a drying furnace for removing the impurities may be from 5 minutes to 20 minutes at a temperature of 100 ℃ to 150 ℃. As the drying time increases, the characteristics of the electrochromic device may be improved, but the degree of improvement is insignificant, and there is no need to lengthen it because it is for shortening the process time of the present invention.

In one embodiment, the electrolyte injection and sealing step 130 may include injecting and sealing an electrolyte between the tungsten oxide thin film and the second transparent conductive oxide substrate.

In one embodiment, the electrolyte to be inserted between the transparent conductive oxide of the first transparent conductive oxide substrate and the transparent conductive oxide of the second transparent conductive oxide substrate plays a role of causing tungsten oxide and coloring/discoloration when voltage is applied. The medium through which lithium ions can move is a solvent such as polycarbonate (PC), poly(vinylidene fluoride), copolymer of vinylidene fluoride and hexafluoropropylene, polyamide, aromatic polyamide, polyolefin, polyester. , Polyimide, poly(meth)acrylate, and may include at least one selected from the group consisting of polyacrylonitrile. LiClO ₄ , LiCl, LiBr, LiI, LiBF ₄ , LiB ₁₀ Cl ₁₀ , LiPF ₆ , LiCF ₃ SO ₃ , LiCF ₃ CO ₂ , LiAsF ₆ , LiSbF ₆ , LiAlCl ₄ , CH ₃ SO ₃ Li, CF ₃ SO ₃ Li, (CF ₃ SO ₂ ) ₂ NLi, lithium chloroborane, lithium lower aliphatic carboxylic acid, and lithium tetraphenylborate may contain at least any one selected from the group consisting of have.

In one embodiment, the concentration of the electrolyte may be 0.5 M to 1.5 M. If the concentration of the electrolyte is less than 0.5 M, the concentration of reacting lithium ions may not be able to contribute to the device characteristics, and if the concentration of the electrolyte is greater than 1.5 M, residual lithium remains or a secondary reactant that forms a chemical potential is formed. This can have an adverse effect on the electrochromic device.

The electrochromic device is driven by a low voltage according to the manufacturing method of an electrochromic device according to an embodiment of the present invention, and has a fast response speed within 60 seconds and a linear light transmittance control through discoloration, and has excellent durability and lifespan. The device can be manufactured.

The conventional electrochromic device manufacturing method is manufactured through a high cost and complex process method, but the introduction of a wet oxidation treatment method different from the existing method reduces manufacturing cost and reduces the time by simplifying the process method, and productivity and mass production problems Can be improved.

Another aspect of the present invention is manufactured by the method of manufacturing an electrochromic device according to an aspect of the present invention, and has a light transmittance of 80% or more when an electric field is applied, and a light transmittance of 5% to 30% when an electric field is removed. , It provides an electrochromic device in which the driving voltage is 1 V to 3 V, and the response speed is within 60 seconds.

2 is a cross-sectional view of an electrochromic device according to an embodiment of the present invention. Referring to FIG. 2, an electrochromic device 200 according to an embodiment of the present invention includes a first transparent conductive substrate 210 including a first substrate 212 and a second transparent conductive oxide 214 , A tungsten oxide thin film 220, an electrolyte 230, a second substrate 242, and a second transparent conductive substrate 240 including a second transparent conductive oxide 244 may be included.

In one embodiment, the first transparent conductive oxide substrate 210 may be a first transparent conductive oxide 214 formed on the first substrate 212.

In one embodiment, the first substrate 212 is glass, alumina, SiO ₂ , polyethylene terephalate (PET), polyethylene naphthalate (PEN), polyethersulfonate (PES) And at least one selected from the group consisting of polycarbonate (PC).

In one embodiment, the first transparent conductive oxide 214 is, indium tin oxide (ITO), indium zinc oxide (IZO), fluorine-doped tin oxide (FTO), Al-doped zinc oxide (AZO), Ga -It may include at least one selected from the group consisting of doped ZnO (GZO) and transparent conductive oxide (TCO). The transparent conductive oxide may be an electrode, and the first transparent conductive oxide 214 of the first transparent conductive oxide substrate 210 is a lower electrode, and a second transparent conductive oxide of the second transparent conductive oxide substrate 240 ( 244 may be an upper electrode. Alternatively, the first transparent conductive oxide 214 of the first transparent conductive oxide substrate 210 may be an upper electrode, and the second transparent conductive oxide 244 of the second transparent conductive oxide substrate 240 may be a lower electrode. The upper electrode and the lower electrode may have the same substrate and transparent conductive oxide, or may be different from each other.

In one embodiment, the thickness of the tungsten oxide thin film 220 may be 150 nm to 180 nm. When the tungsten oxide thin film is less than 150 nm, stability and durability are deteriorated due to the number of driving changes of the electrochromic device and the number of driving changes in color and high voltage, and when it exceeds 180 nm, the sheet resistance of the electrochromic device increases and the transmittance is increased. There is a bad problem.

In one embodiment, the electrolyte 230 serves to cause coloration and discoloration with the tungsten oxide thin film 220 when voltage is applied. The medium through which lithium ions can move is a solvent such as polycarbonate (PC), poly(vinylidene fluoride), copolymer of vinylidene fluoride and hexafluoropropylene, polyamide, aromatic polyamide, polyolefin, polyester. , Polyimide, poly(meth)acrylate, and may include at least one selected from the group consisting of polyacrylonitrile. LiClO ₄ , LiCl, LiBr, LiI, LiBF ₄ , LiB ₁₀ Cl ₁₀ , LiPF ₆ , LiCF ₃ SO ₃ , LiCF ₃ CO ₂ , LiAsF ₆ , LiSbF ₆ , LiAlCl ₄ , CH ₃ SO ₃ Li, CF ₃ SO ₃ Li, (CF ₃ SO ₂ ) ₂ NLi, lithium chloroborane, lithium lower aliphatic carboxylic acid, and lithium tetraphenylborate may contain at least any one selected from the group consisting of have.

The electrochromic device of the present invention may be driven by a device even at a low voltage, and may have a fast response speed and linear light transmittance control through discoloration, and excellent durability and longevity.

Hereinafter, the present invention will be described in detail with reference to the following Examples and Comparative Examples. However, the technical idea of the present invention is not limited or limited thereby.

[Example]

A 140 nm tungsten thin film was deposited on the ITO surface of the ITO glass substrate as an upper electrode under the condition of plasma formation using a tungsten target in DC sputter. Subsequently, a 35% concentration hydrogen peroxide (H ₂ O ₂ ) solution (H ₂ O: H ₂ O ₂ = 65: 35) was applied to the tungsten thin film by a drop casting method to perform wet oxidation treatment. The applied hydrogen peroxide solution reacted with tungsten at room temperature to form tungsten oxide in ceramic. When the hydrogen peroxide solution applied to the upper electrode reacts with tungsten, distilled water or a reactant included in the solution may adversely affect the quality, durability, and life of the device. Therefore, a process of removing impurities was performed. In the process of removing residues and impurities after the wet oxidation treatment, distilled water was first washed, and the remaining distilled water was removed by secondarily using an air knife. Then, it was dried in a drying furnace at a temperature of 120° C. for 5 minutes to evaporate the residue. At this time, the residue contained distilled water, hydrogen peroxide, tungsten oxide that fell off, and H ₂ O after the reaction.

3 is a photograph of impurities formed after applying a hydrogen peroxide solution on the tungsten thin film according to an embodiment of the present invention, and FIG. 4 is a photograph of impurities after applying the hydrogen peroxide solution on the tungsten thin film according to an embodiment of the present invention. This is a picture after it has been removed. It can be seen that the tungsten oxide thin film that has gone through the impurity removal process is clean. Subsequently, an electrolyte was applied between the ITO glass substrate as the upper electrode and the lower electrode on which the tungsten oxide thin film was formed. Polycarbonate (PC) was used as a solvent for lithium ions to move, and lithium perchlorate (LiClO ₄ ) was used as a solute to provide lithium ions used in the electrolyte at a concentration of 0.7 M and 1.0 M. A liquid lithium ion electrolyte was prepared in. To apply the electrolyte, a glass 5 mm wide and 7 μm thick was placed in a square shape on the edge of the tungsten oxide thin film formed on the lower electrode and bonded with a sealant to form a gap. Proceeding in the manner of coating, an electrochromic device was manufactured.

5 is a photograph before applying a 5 V voltage to an electrochromic device according to an embodiment of the present invention, and FIG. 6 is a photograph after applying a 5 V voltage to an electrochromic device according to an embodiment of the present invention. Referring to FIGS. 5 and 6, it can be seen that the electrochromic device was colored before applying a voltage and then decolored after applying the voltage. It can be seen that the drive works well even at low voltage.

7 is a light spectrum showing the intensity of light according to the concentration of lithium ions in the electrochromic device according to an embodiment of the present invention. Referring to FIG. 7, it can be seen that the characteristics of color transmittance and discoloration transmittance are most excellent at 0.7 M.

As described above, although the embodiments have been described by the limited embodiments and drawings, various modifications and variations are possible from the above description by those of ordinary skill in the art. For example, even if the described techniques are performed in a different order from the described method, and/or the described components are combined or combined in a form different from the described method, or are replaced or substituted by other components or equivalents. Appropriate results can be achieved. Therefore, other implementations, other embodiments, and claims and equivalents fall within the scope of the claims to be described later.

Claims (5)

Forming a tungsten thin film on the first transparent conductive oxide substrate;
Oxidizing the tungsten thin film into a tungsten oxide thin film by applying an acidic solution on the tungsten thin film; And
Injecting and sealing an electrolyte between the tungsten oxide thin film and the second transparent conductive oxide substrate;
Including,
The concentration of the acidic solution is from 20% to 40%,
Method of manufacturing an electrochromic device.
The method of claim 1,
The method of forming the tungsten thin film includes a sputtering method, an atomic layer deposition (ALD) method, a plasma enhanced amotic layer deposition (PE-ALD) method, a chemical vapor deposition method. Vapor Deposition (CVD) method, Plasma-Enhanced Chamical Vapor Deposition (PE-CVD) method, Pulsed Laser Deposition (PLD) method and Molecular Beam Epitaxy (MBE) method Including at least any one selected from the group consisting of,
The tungsten thin film is formed to a thickness of 140 nm to 170 nm,
Method of manufacturing an electrochromic device.

The method of claim 1,
The acidic solution contains at least any one selected from the group consisting of hydrogen peroxide, nitric acid, hydrochloric acid, sulfuric acid and hydrofluoric acid,
Method of manufacturing an electrochromic device.

The method of claim 1,
After the step of oxidizing the tungsten thin film to a tungsten oxide thin film by applying an acidic solution on the tungsten thin film,
Removing impurities formed on the tungsten oxide thin film;
Including more,
The step of removing the impurities formed on the tungsten oxide thin film,
Washing the first transparent conductive oxide substrate including the tungsten oxide thin film with distilled water;
Removing the distilled water using an air knife; And
Drying in a drying furnace to evaporate the residue;
It includes,
Method for manufacturing an electrochromic device.

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