KR20170142364A - Flexible electrochromic device having an electrode with high quality graphene complex and method of manufacturing the same - Google Patents

Abstract

Provided are a flexible electrochromic device using a high-quality graphene complex electrode with high reliability and excellent properties and a manufacturing method thereof, using a high-quality graphene and a transparent conductive layer as one electrode portion. The manufacturing method of an electrochromic device comprises: a graphene growth step of growing graphene on a growth substrate; a step of performing an atomic layer deposition process on the graphene layer to form an atomic layer; a first transparent conductive layer forming step of forming a transparent conductive layer on the atomic layer; a step of sequentially forming an ion storage layer, an electrolyte layer, and an electrochromic layer on the transparent conductive layer; and a second transparent conductive layer forming step of forming a transparent conductive layer on the electrochromic layer.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible electrochromic device using a high quality graphene composite electrode as one electrode and a method for manufacturing the same,

The present invention relates to a flexible electrochromic device using a high-quality graphene composite electrode as one electrode and a method of manufacturing the same, and more particularly to a flexible electrochromic device using a high-quality graphene and a transparent conductive layer in an electrochromic unit or an ion storage unit And a method of manufacturing the same.

An electrochromic device is a device in which a discoloration substance is stimulated by an external stimulus such as electricity, a chemical reaction occurs, and a discoloring effect occurs visually. In the electrochromic device, a first electrode formed on a first substrate and a second electrode formed on a second substrate are opposed to each other, and an ion storage layer, an electrolyte layer and an electrochromic layer are laminated between the first and second electrodes Structure. Further, in order to protect the plurality of layers from the outside, a barrier or the like using a polymer or the like is provided between the outer side of the plurality of layers, and between the first and second substrates.

In the electrochromic device, when a potential difference is generated between the first electrode and the second electrode, ions contained in the electrolyte layer migrate into the electrochromic layer and undergo oxidation / reduction reaction so that the color changes visually or the color hue changes Is a device using the principle that For example, in the case of a device in which the electrochromic layer is colored by a reduction reaction, the electrochromic layer is colored when a current flows from the electrochromic layer to the ion storage layer. On the contrary, when an electric current flows from the ion storage layer to the electrochromic layer, Discoloration occurs in the discoloration layer. Of course, when the electrochromic layer is a substance that is colored by the oxidation reaction, coloration and decolorization reaction occur in the current flow in the direction opposite to the example.

Such an electrochromic device is widely used as a smart window that utilizes light transmission characteristics, a room mirror for an automobile, a shield plate for a transparent display, and a display device.

Considering the range and ease of use of the electrochromic device, the electrochromic device needs to be fabricated to have flexibility, and transparency of the electrode is very important. Therefore, a transparent conductive oxide such as indium tin oxide is mainly used. In order to achieve conductivity for use as an electrode material, indium tin oxide must be formed to a thickness of more than a certain thickness. However, as the thickness of indium tin oxide is increased, the flexibility and transparency of the electrode are lowered.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and it is an object of the present invention to provide a high-reliability electrochromic device having excellent characteristics using a high quality graphene composite electrode as one electrode of an electrochromic device and a method of manufacturing the same. .

According to another aspect of the present invention, there is provided a method of fabricating an electrochromic device, including: growing graphene on a growth substrate; Performing an atomic layer deposition process on the graphene layer to form an atomic layer; A first forming step of forming a transparent conductive layer on the atomic layer; Sequentially forming an ion storage layer, an electrolyte layer, and an electrochromic layer on the first transparent conductive layer; And a second transparent conductive layer forming step of forming a transparent conductive layer on the electrochromic layer.

The step of forming the atomic layer may be to deposit the atomic layer to heal the defects of the graphene layer on the graphene layer. The atomic layer may be a layer of atoms of a metal or metal oxide.

A method of manufacturing an electrochromic device according to the present invention includes: removing a growth substrate; And bonding the graphene layer to the flexible substrate.

The flexible substrate may be formed of a material such as polymethyl methacrylate (PMMA), polyethyleneterephthalate (PET), polyethylenenaphthalate (PEN), polycarbonate (PC), and polyimide ), And the like.

According to another aspect of the present invention, there is provided a flexible substrate comprising: a flexible substrate; A graphene layer formed on the flexible substrate; An atomic layer formed on the graphene layer; And a first transparent conductive layer formed on the atomic layer; An electrochromic unit sequentially comprising an ion storage layer, an electrolyte layer, and an electrochromic layer on the first transparent conductive layer; And a second transparent conductive layer formed on the electrochromic portion.

The ion storage layer and the electrochromic layer may include a transition metal oxide or a polymer that undergoes discoloration and discoloration of the thin film by an electrochemical reaction. Further, the electrolyte layer may include a solid electrolyte.

As described above, the high-quality graphene composite electrode applied to the electrochromic device according to the embodiments of the present invention heats graphene defects by applying an atomic layer having a size similar to that of the defects, It can be used as an electrode substrate, and quality deterioration due to defects can be minimized even in a process of applying a high energy such as a transparent conductive layer, for example, an ITO layer forming process, so that the quality of a transparent electrode used in an electrochromic device can be maintained There is an effect that can be.

In addition, the conductivity of the electrode is ensured due to high-quality graphene, so that the thickness of the transparent conductive layer is minimized, and the flexibility and transparency of the electrochromic device formed thereby can be increased. Also, since graphene acts as a barrier between the transparent conductive layer and the growth substrate, the components of the growth substrate are prevented from diffusing into the transparent conductive layer, so that the conductivity and transparency of the transparent conductive layer are maintained, It is possible to manufacture an electrochromic device.

FIGS. 1 to 6 are views provided for explaining a method of manufacturing an electrochromic device according to an embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, the embodiments of the present invention can be modified into various other forms, and the scope of the present invention is not limited to the embodiments described below. The embodiments of the present invention are provided to enable those skilled in the art to more fully understand the present invention. It should be understood that while the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein, The present invention is not limited thereto.

FIGS. 1 to 6 are views provided for explaining a method of manufacturing an electrochromic device according to an embodiment of the present invention. A method of fabricating an electrochromic device according to an embodiment of the present invention includes a graphene growth step of growing a graphene layer 120 on a growth substrate 110; Performing an atomic layer (130) deposition process on the graphene layer (120) to form an atomic layer (130); Forming a first transparent conductive layer (140) that forms a transparent conductive layer on the atomic layer (130); Sequentially forming an ion storage layer (151), an electrolyte layer (152), and an electrochromic layer (153) on the first transparent conductive layer (140); And a second transparent conductive layer (160) forming a transparent conductive layer on the electrochromic layer (153).

In the present invention, a method of manufacturing an electrochromic device 100 including an electrode in which a graphene layer is formed on a transparent conductive layer in an electrochromic device including a transparent conductive layer as an electrode to complement the physical properties of the transparent electroconductive layer .

Graphene is formed by connecting a plurality of carbon atoms to each other through a covalent bond to form a polycyclic aromatic molecule to form a layer or a sheet form. The carbon atoms covalently bonded in the graphene layer form a 6-membered ring as a basic repeating unit, but the graphene layer may further include a 5-membered ring or a 7-membered ring. In particular, when the growth direction of graphene differs at the domain boundary of graphene, the respective domains collide to form a 5-membered ring or a 7-membered ring, and this irregular arrangement of crystals causes degradation of graphene quality.

The domain of graphene refers to the region where crystals increase as the graphene grows from one point and the resulting horizontal expansion occurs. That is, a graphene within a boundary formed at a point where a region of graphene formed at a certain point and a region of graphene formed at another point meet, is called a domain. Due to the difference in the growth directions of the different domains at the interface of the graphene domain, irregular crystal arrays occur as described above when the domains are contacted, and this irregularity acts as a defect of graphene.

Graphene is a single layer of covalently bonded carbon atoms (usually sp2 bonds). The graphene may have a variety of structures, and such a structure may vary depending on the content of the five-membered ring and / or the seven-membered ring which may be contained in the graphene. The graphene may be composed of a single layer of graphene as described above, but it is also possible to form a plurality of layers by stacking a plurality of these graphenes, and usually the lateral end portions of the graphene can be saturated with hydrogen atoms.

In order to manufacture an electrochromic device according to the present invention, a graphene growth step is performed in which a graphene layer 120 is grown on a growth substrate 110 (FIG. 1). The graphene can be synthesized in various ways, in this embodiment, it is synthesized by a direct growth method in which graphene is synthesized directly on a growth substrate. The growth substrate 110 functions as a seed layer for growing graphene, and is not limited to a specific material. For example, the growth substrate 110 may include at least one of Ni, Co, Fe, Pt, Au, Al, Cr, Cu, Mg, Mn, Mo, Rh, Si, Ta, Ti, W, U, V, Zr, , Baikong, stainless steel and Ge, or an alloy thereof. Alternatively, the growth substrate 110 may be a SiO ₂ substrate or a glass substrate.

The growth substrate 110 may further include a catalyst layer (not shown) that adsorbs carbon well to facilitate growth of graphene. The catalyst layer is not limited to a specific material and may be formed of the same or different material as the growth substrate 110. On the other hand, the thickness of the catalyst layer is not limited and may be a thin film or a thick film.

When the growth substrate is prepared, a graphen growth step is performed in which graphene is grown on the growth substrate 110. As a method of forming the graphene layer 120 on the growth substrate 110, a chemical vapor deposition (CVD) method may be used. Herein, the chemical vapor deposition may be performed by a method such as high temperature chemical vapor deposition (RTCVD), inductively coupled plasma chemical vapor deposition (ICP) CVD, low pressure chemical vapor deposition (LPCVD), atmospheric pressure chemical vapor deposition (APCVD), metal organic chemical vapor deposition Or chemical vapor deposition (PECVD).

The growth substrate 110 is put into the reactor and the graphene layer 120 can be formed by growing the graphene through the atmospheric pressure heat treatment under the supply condition of the reaction gas used as a carbon source.

The heat treatment temperature for growth of graphene may be 300 ° C to 2,000 ° C. When the growth substrate 110 is reacted with a carbon source at high temperature and pressure, the supplied carbon is dissolved or adsorbed in the growth substrate 110, and then dissolved and adsorbed carbon atoms are crystallized on the surface of the growth substrate 110, Thereby forming a crystal structure.

Meanwhile, the number of layers of the graphene layer 120 can be controlled by controlling the type and thickness of the growth substrate 110 (including the catalyst layer), the reaction time, the cooling rate, and the concentration of the reaction gas in the above-

The carbon source may be carbon monoxide, carbon dioxide, methane, ethane, ethylene, ethanol, acetylene, propane, butane, butadiene, pentane, pentene, cyclopentadiene, hexane, cyclohexane, benzene or toluene.

By controlling the temperature while supplying the reaction gas containing the carbon source to the gas phase, the carbon atoms of the reaction gas form a hexagonal plate-like structure on the surface of the growth substrate 110 to synthesize graphene (FIG.

When the graphene layer 120 is formed, a step of depositing an atomic layer 130 on the graphene layer 120 to form the atomic layer 130 is performed. Referring to FIG. 1, a graphene crystal structure 121 having a hexagonal structure is formed on a graphene layer 120, and three graphene domains collide to form a graphene domain boundary 122. This graphene domain boundary 122 destroys the crystal structure of the ideal hexagonal structure of the graphene layer 120, which acts as a graphene defect. That is, the conductivity of the graphene layer 120 is deteriorated and a leakage current is generated, which causes a problem that the reliability of the product is deteriorated in manufacturing transparent electrodes using the graphene layer 120 and the like. In addition, the graphene layer 122 becomes a region in which energy or the like coheres under high-temperature and high-pressure conditions during a subsequent process, thereby further damaging the graphene layer 120.

In the method of manufacturing an electrochromic device according to the present invention, a step of forming an atomic layer 130 by performing an atomic layer deposition process on a graphene layer is performed as a method of healing the graphene defects 122. Referring to FIG. 2, an atomic layer is deposited on the graphene defect 122. The presence of the atomic layer 130 on the graphene layer 120 in the present invention means that the atomic layer 130 is formed on the upper surface of the graphene layer 120, Is a concept including a state in which an atomic line is arranged to apply a defect, that is, an atomic arrangement forming part of one layer, in the pin defect 122 portion. This type of atomic arrangement can be implemented by atomic layer deposition (ALD) process.

The ALD process is a process in which a precursor gas of an atom to be deposited is injected and a reactive gas is injected together to form a thin film by layering atoms on a substrate to be deposited.

For example, a single layer of atomic layer 130 is formed on the graphene layer 120 through a multi-step ALD process. However, due to the graphene defects 122 present on the graphene layer 120, the atomic layer 130 is not formed as a single layer over the graphene layer 120 according to the ALD process, 122). That is, an atomic layer by ALD is formed along the graphene defects 122 as shown in FIG.

3 is a cross-sectional view of the graphene layer formed with the atomic layer in FIG. The atomic layer 130 is intensively arranged in the graphene defects 122 of the graphene layer 120 because the arrangement of the atoms according to the ALD process is preferentially deposited on portions of the graphene defects 122, This can be interpreted as

As the atomic layer 130, an atomic layer of a metal or a metal oxide may be formed. For example, a metal oxide atomic layer such as aluminum oxide or zinc oxide may be formed. In the case of aluminum oxide, in the case of the graphene layer 120 having a thickness of 1 to 10 nm, since the diameter of the atomic layer is about 0.67 angstroms, an aluminum oxide atomic layer is formed inside the graphene defects 122, And may be formed along the graphene domain boundary 122 in the form of a line.

When the atomic layer 130 is formed around the graphene defects 122, a high-temperature and high-energy process for forming the first transparent conductive layer 140, for example, a vacuum deposition process / a plasma deposition process, Excessive concentration of energy toward the graphene defects 122 can be suppressed. Accordingly, it is possible to prevent the graphene defects 122 from being enlarged and deterioration of the physical properties of the graphene layer 120 when the first transparent conductive layer 140 is formed.

The atomic layer 130 may be formed by repeating the atomic layer deposition process a plurality of times. The number of atomic layer deposition times can be selected in consideration of the thickness of the graphene layer 120, the size and frequency of the graphene defects 122, and the like.

If the atomic layer deposition process is repeated many times, the atomic layer 130 may be implemented as a single layer.

The atomic layer 130 may include a metal or a metal oxide as described above, but may be formed so as not to adversely affect the conductivity of the graphene layer 120 or the first transparent conductive layer 140. That is, although a slight decrease in conductivity may occur in the graphene layer 120 due to the introduction of an oxide-type heterogeneous material, since it is an atomic layer, it does not adversely affect the conductivity of the first transparent conductive layer 140, The effect of the atomic layer on the graphene composite electrode can be neglected, since defects occurring when the transparent conductive layer 140 is formed are minimized.

Once the atomic layer 130 is formed, a transparent conductive layer is formed on the atomic layer 130 to form the first transparent conductive layer 140, which functions as one electrode (FIG. 4). The transparent conductive layer 140 is formed of a transparent conductive material such as indium tin oxide (ITO), indium zinc oxide (IZO), F-doped tin oxide (FTO), antimony tin oxide (ATO) AZO (ZnO: Al), GZO (ZnO: Ga), a-IGZO (In 2 O 3: Ga 2 O 3: ZnO), MgIn 2 O 4, Zn 2 SnO 4, ZnSnO 3, (Ga, In) 2 At least one metal oxide selected from the group consisting of Cu, Al, Sn, In ₂ O ₃ , Zn ₂ In ₂ O ₅ , InSn ₃ O ₁₂ , In ₂ O ₃ , SnO ₂ , Cd ₂ SnO ₄ , CdSnO ₃ and CdIn ₂ O ₄ , At least one metal selected from the group consisting of Ni, W, Ti, Cr, Co, Zn, Ta, V, Au, Ag, TiN and Pt, or nanowires such as Cu or Ag.

The transparent conductive layer 140 may be formed using a physical or chemical deposition process such as thermal deposition, chemical vapor deposition, or sputtering, or may be formed using a coating process.

The graphene layer 120, the atomic layer 130 and the first transparent conductive layer 140 on the growth substrate 110 according to the present invention can be used as a transparent electrode of an electrochromic device. Although the graphene layer 120 can be used as a transparent electrode independently by taking advantage of the flexibility, transparency and thinness of the thickness, it is difficult to attain a desired level of conductivity as an electrode, and thus it is difficult to use it as a single electrode. The first transparent conductive layer 140 exhibits high transparency and conductivity but is low in flexibility and is difficult to be realized as a flexible electrode. In order to secure a high conductivity, the thickness of the electrode becomes thick, thereby decreasing transparency and flexibility. There is a difficulty in achieving the desired quality.

Any one of the electrodes of the electrochromic device according to the present invention may include a first transparent conductive layer 140 on the graphene layer 120 to complement the low conductivity of the graphene layer 120, 140) to reduce transparency and ensure flexibility of the electrode. The graphene layer 120 between the growth substrate 110 and the first transparent conductive layer 140 prevents impurities from flowing into the growth substrate 110 during the heat treatment of the transparent conductive layer 140, The conductivity and transparency of the conductive layer 140 can be maintained.

An electrochromic portion 150 is formed on the first transparent conductive layer 140 to allow discoloration through voltage application. An ion storage layer 151, an electrolyte layer 152, and an electrochromic layer 153 may be sequentially formed on the first transparent conductive layer 140. Alternatively, the electrochromic layer 150 may be formed on the first transparent conductive layer 140 in the order of the electrochromic layer 153, the electrolyte layer 152, and the ion storage layer 151.

The ion storage layer 151 is involved in the influx of ions involved in the electrochromic reaction. In the case where ions are emitted from the electrochromic layer 153, ions from the electrochromic layer 153 are accommodated in the ion storage layer 151 and ions are received in the electrochromic layer 153 And provides corresponding ions in the ion storage layer 151. The ion storage layer 151 may be an ion storage material or an oxidation / reduction coloring material for storing a plurality of positive ions such as hydrogen ions or lithium ions or other kinds of ions participating in electrochromism.

The ion storage layer 151 may function as another electrochromic layer for increasing the discoloration efficiency of the device together with the electrochromic layer 153. The ion storage layer 151 of the electrochromic device may be composed of an electrochromic material having a corresponding reaction in the redox reaction with the electrochromic layer 153. That is, when the electrochromic layer 153 is a reducing discoloring material, the ion storage layer 151 may be an oxidative discoloring material, or vice versa. When the ion storage layer 151 of the electrochromic device is composed of another electrochromic layer, the coloring transmittance of the device is reduced and the discoloration efficiency is increased.

The electrolyte layer 152 is formed on the ion storage layer 151, and a material containing ions involved in the electrochromic reaction may be used. For example, the electrolyte layer 152 is _{Ta 2 O 5, LiClO 4,} LiNbO 3, Li 3 + x PO 4 - x N x (LiPON), LiVO 3 / SiO 2 / Li 4 SiO 4 -Li 3 VO 4 (LVSO), LiPF ₆ , Li ₃ PO ₄ , and the like. The electrolyte may be a solid electrolyte. The electrolyte layer 152 may be a single layer using a single material or a multi-layer structure formed by alternating heterogeneous materials.

The electrochromic layer 153 is formed on the electrolyte layer 152. The electrochromic layer 153 may be formed using an electrochromic material whose color changes according to an electrical signal, and the electrochromic material may be an inorganic material or an organic material.

The electrochromic material used as the ion storage layer 151 and the electrochromic layer 153 may be selected flexibly depending on the reaction of the oxidation reaction or the reduction reaction, Can be selected so that the oxidation-reduction reaction can be completed when they are connected to each other. When the electrochromic material used as the ion storage layer 151 and the electrochromic layer 153 is an inorganic material, a transition metal oxide deposited in the form of a thin film may be used. NiO, Cr ₂ O ₃ , MnO ₂ , Rh ₂ At least one selected from O ₃ , CoO _x , Ir (OH) _x , Fe ₂ O ₃ , WO ₃ , ZnO, NbO ₅ , V ₂ O ₅ , TiO ₂ and MoO ₃ can be used. The organic electrochromic material may be a viologen compound, a diphtahlocyanine compound or a tetrathiafulvalene compound, and a polyaniline, polythiophene, or 3,4-ethylenedioxythiophene (PEDOT) compound. There are a variety of macromolecular compounds. Organic electrochromic materials are disadvantageous in that they can be decomposed into sunlight to shorten the lifetime, but they can be widely used because they can produce a desired color by properly mixing them.

When the electrochromic portion 150 is formed, a second transparent conductive layer 160 is formed as an electrode facing the first transparent conductive layer 140 (FIG. 5). The second transparent conductive layer 160 may be implemented with a transparent and conductive metal oxide or the like that is the same as or similar to the first transparent conductive layer 140.

Unlike the first transparent conductive layer 140, the second transparent conductive layer 160 is not formed with the graphene layer 120. Accordingly, the second transparent conductive layer 160 may be formed to have a thickness larger than that of the first transparent conductive layer 140 or may be formed of a material having higher conductivity, if necessary.

A second transparent conductive layer 160 is finally formed to form an electrochromic element 160 leading to the graphene layer 120, the first transparent conductive layer 140, the electrochromic portion 150 and the second transparent conductive layer 160 When the necessary elements are completed, the growth substrate 110 for growth of graphene is removed, and the flexible substrate 170 is attached to the graphene layer 120 (FIG. 6).

The electrochromic device 100 according to the present invention includes a flexible substrate 170; A graphene layer 120 formed on the flexible substrate 170; An atomic layer 130 formed on the graphene layer 120; And a first transparent conductive layer (140) formed on the atomic layer (130); An electrochromic portion 150 sequentially including an ion storage layer 151, an electrolyte layer 152, and an electrochromic layer 153 on the first transparent conductive layer 140; And a second transparent conductive layer 160 formed on the electrochromic portion 150.

The flexible substrate 150 is a flexible substrate having a plastic substrate such as poly methyl methacrylate (PMMA), polyethylene terephthalate (PET), polyethylenenaphthalate , PEN), a polycarbonate (PC), and a transparent polymer film such as polyimide (PI).

The removal of the growth substrate 110 may be performed using a roll-to-roll apparatus including a chamber containing an etching solution for selectively removing the growth substrate 110 and a chamber containing an etching solution. The etching solution may be selected corresponding to the type of the growth substrate 110, for example, hydrogen fluoride (HF), buffered oxide etch (BOE), ferric chloride (FeCl ₃ ) solution, or ferric nitrate Fe (NO ₃ ) ₃ ) solution.

As described above, in the embodiments of the present invention, the electrode of the electrochromic device is implemented using the transparent conductive layer, and the conductivity of the transparent conductive layer is improved by using the defective healed graphene layer in any one of the transparent conductive layer electrodes And the flexible substrate can be attached to the graphene layer to produce a flexible electrochromic device.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, many modifications and changes may be made by those skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims. The present invention can be variously modified and changed by those skilled in the art, and it is also within the scope of the present invention.

100 electrochromic device 110 growth substrate
120 graphene layer 121 graphene crystal structure
122 graphene defect 130 atomic layer
140 first transparent conductive layer 150 electrochromic portion
151 Ion storage layer 152 Electrolyte layer
153 Electrochromic layer 160 Second transparent conductive layer
170 soft substrate

Claims (8)

A graphene growth step of growing graphene on a growth substrate;
Performing an atomic layer deposition process on the graphene layer to form an atomic layer;
A first transparent conductive layer forming step of forming a transparent conductive layer on the atomic layer;
Sequentially forming an ion storage layer, an electrolyte layer, and an electrochromic layer on the first transparent conductive layer; And
And a second transparent conductive layer forming step of forming a transparent conductive layer on the electrochromic layer.
The method according to claim 1,
Wherein forming the atomic layer comprises:
Wherein an atomic layer is deposited on the graphene layer to heal defects of the graphene layer.
The method according to claim 1,
Wherein the atomic layer is a layer of atoms of a metal or a metal oxide.
The method according to claim 1,
Removing the growth substrate; And
And bonding the graphene layer to the flexible substrate.
The method of claim 4,
The flexible substrate may be formed of a material selected from the group consisting of poly (methyl methacrylate), PMMA, polyethyleneterephthalate (PET), polyethylenenaphthalate (PEN), polycarbonate (PC), and polyimide PI), and the like. The electrochromic device according to claim 1,
A flexible substrate;
A graphene layer formed on the flexible substrate;
An atomic layer formed on the graphene layer;
A first transparent conductive layer formed on the atomic layer;
An electrochromic portion sequentially including an ion storage layer, an electrolyte layer, and an electrochromic layer on the first transparent conductive layer; And
And a second transparent conductive layer formed on the electrochromic portion.
The method of claim 6,
Wherein the ion storage layer and the electrochromic layer include a transition metal oxide or a polymer that undergoes discoloration and discoloration of a thin film by an electrochemical reaction.
The method of claim 6,
Wherein the electrolyte layer comprises a solid electrolyte.

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