KR102437446B1 - Electrochromic device comprising inorganic coating layer formed on the electrochromic layer - Google Patents

Abstract

The present application relates to an electrochromic device with reduced leakage current by an inorganic material for surface modification coated on the electrochromic layer, and more particularly, an inorganic coupling agent at the interface between the electrolyte and the color-changing layer of the electrochromic device. It relates to improving the stability and durability of the electrochromic element by reducing the leakage of the current flowing in the electrochromic element through the electrolyte by coating it.

Description

Electrochromic device comprising inorganic coating layer formed on the electrochromic layer

The present application relates to an electrochromic device in which leakage current is reduced by an inorganic layer coated on the electrochromic layer. More particularly, it relates to improving the stability and durability of the electrochromic element by forming an inorganic coating layer at the interface between the electrolyte and the color-changing layer of the electrochromic element to reduce leakage of current flowing in the electrochromic element through the electrolyte.

Electrochromism refers to a phenomenon in which the optical properties of an electrochromic material are changed by an electrochemical oxidation or reduction reaction, and a device using this phenomenon is called an electrochromic device. In general, an electrochromic element includes an electrochromic layer, an electrolyte layer, and an ion storage layer between two opposing electrodes, and each of the electrochromic layer and the ion storage layer contains a color-changing material whose reaction for color development is opposite to each other. Included.

In general, a change in the optical properties of a device can be realized through a color change of a layer or thin film containing an electrochromic material. This electrochromic phenomenon is mainly observed in transition metal oxides having a high oxidation number, and the electrochromic properties appearing differ depending on the material. For example, when tungsten oxide (WO ₃ ) close to colorless and transparent is used as an electrochromic material, when electrolyte ions and electrons move by voltage application, a reduction reaction occurs, and the color of the layer or thin film containing the electrochromic material It is discolored to this blue system. Conversely, when an oxidation reaction occurs in the layer or thin film, the layer or thin film is decolorized to its original transparent state.

On the other hand, the current flowing in the device by the voltage applied to the electrochromic device flows through the electrolyte constituting the device (current leakage) occurs. Preventing such leakage current is one of the important factors to increase the lifetime of the device.

Therefore, for example, in the case of a device having a stacked structure of several materials, such as a transistor or a display device, various existing prior technologies such as the use of a material for preventing leakage current or post-processing in a process exist, and in the electrochromic device There is a need to prepare a plan for reducing leakage current.

Accordingly, it is an object of the present application to provide an electrochromic element having excellent efficiency, stability and durability by reducing power consumption by reducing leakage of current flowing in the electrochromic element through the electrolyte.

One aspect of the present application relates to an electrochromic device.

In one example, the electrode layer; an electrochromic layer formed on the electrode layer; an electrolyte layer formed on the electrochromic layer; and an inorganic coating layer disposed between the electrochromic layer and the electrolyte layer.

In one example, it may further include an ion storage layer formed on the opposite surface of the electrolyte layer facing one surface of the inorganic coating layer, and an electrode layer.

In one example, the electrode layer may be a transparent electrode or a reflective electrode.

In one example, the transparent electrode may include a transparent conductive compound (TCO); conductive polymers; silver nanowires; And it may include one selected from the group consisting of a metal mesh.

In one example, the transparent electrode may have a thickness in the range of 1 nm to 1 μm, and transmittance for visible light in the range of 70% to 95%.

In one example, the electrochromic layer may include one or more metal oxides selected from the group consisting of Cr, Mn, Fe, Co, Ni, Li, Rh, Ir, Ti, Nb, Mo, V, Ta, and W. .

In one example, the electrochromic layer may be an electrochromic device satisfying the following [General Formula 1]:

[General formula 1]

ΔT(%) = T ₁ - T ₂ ≥ 30

In Formula 1, T ₁ is the transmittance of visible light when the electrochromic layer is decolorized, and T ₂ is the transmittance of visible light when the electrochromic layer is colored.

In one example, the electrolyte layer may include at least one selected from the group consisting of a liquid electrolyte, a gel-polymer electrolyte, and an inorganic solid electrolyte.

In one example, the electrolyte layer may have a thickness of 30 μm to 200 μm, and a light transmittance of 70% to 95% for visible light.

In one example, the inorganic coating layer may include a silane (Si _n H _2n+2 )-based inorganic material.

In one example, the thickness of the inorganic coating layer may be 15nm to 20nm.

In one example, the surface roughness (thickness uniformity) Ra value according to the ISO4287 standard of the inorganic coating layer may be 0.4 nm to 0.6 nm.

In one example, the ion storage layer may include one or more oxides selected from the group consisting of Cr, Mn, Fe, Co, Ni, Li, Rh, Ir, Ti, Nb, Mo, V, Ta and W.

In one example, an inorganic coating layer disposed between the ion storage layer and the electrode layer may be further included.

In one example, the inorganic coating layer disposed between the ion storage layer and the electrode layer may include a silane (Si _n H _2n+2 )-based inorganic material.

According to an embodiment of the present application, an inorganic coupling agent is coated on the interface between the electrolyte and the color-changing layer of the electrochromic element to maintain the color-changing characteristics, and current flowing in the electrochromic element is prevented from leaking through the electrolyte when a voltage is applied It can effectively control and reduce unnecessary power consumption. Furthermore, it is possible to improve the stability and durability of the electrochromic device and increase the lifespan.

1 schematically illustrates an electrochromic device according to an embodiment of the present application.
2 is a graph of measuring the current per hour (normal current) of the electrochromic device according to an embodiment of the present application, and is a graph of measuring the normal current of Example 1 and Comparative Example 1. Referring to FIG.

Since the present application can have various changes and can have various embodiments, specific embodiments are illustrated in the drawings and described in detail in the detailed description.

However, this is not intended to limit the present application to specific embodiments, and it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present application. In describing the present application, if it is determined that a detailed description of a related known technology may obscure the gist of the present application, the detailed description thereof will be omitted.

Terms such as first, second, etc. may be used to describe various elements, but the elements should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

The terms used in the present application are used only to describe specific embodiments, and are not intended to limit the present application. The singular expression includes the plural expression unless the context clearly dictates otherwise.

In the present application, terms such as “comprises” or “have” are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, but one or more other features It is to be understood that this does not preclude the possibility of the presence or addition of numbers, steps, operations, components, parts, or combinations thereof.

Accordingly, the configuration shown in the embodiment described in the present specification is only the most preferred embodiment of the present application and does not represent all the technical spirit of the present application, so various equivalents that can be substituted for them at the time of the present application and variations.

In addition, it should be understood that the accompanying drawings in the present application are enlarged or reduced for convenience of description.

Hereinafter, the present application will be described in more detail.

The present application relates to an electrode layer in one embodiment; an electrochromic layer formed on the electrode layer; an electrolyte layer formed on the electrochromic layer; and an inorganic coating layer disposed between the electrochromic layer and the electrolyte layer.

In addition, it may further include an ion storage layer and an electrode layer formed on the opposite surface of the electrolyte layer facing one surface of the inorganic coating layer.

Meanwhile, the electrode layer may refer to a configuration capable of supplying electric charge to the electrochromic layer. In one example, it may be a transparent electrode or a reflective electrode. The transparent electrode may include a transparent conductive compound (TCO); conductive polymers; silver nanowires; and at least one selected from the group consisting of a metal mesh. More specifically, ITO (Indium Tin Oxide), FTO (Fluor doped Tin Oxide), AZO (Aluminum doped Zinc Oxide), GZO (Galium doped Zinc Oxide), ATO (Antimony doped Tin Oxide), IZO (Indium doped Zinc Oxide) , at least one transparent conductive compound (TCO) selected from the group consisting of Niobium doped Titanium Oxide (NTO), Zinc Oxide (ZnO), Oxide/Metal/Oxide (OMO), and Cadmium Tin Oxide (CTO); conductive polymers; silver nanowires; and a metal mesh may be used as the electrode material, but the type of material forming the electrode layer is not particularly limited as long as it has conductivity to function as an electrode. In another example, the electrode layer may have a structure in which two or more electrode materials are stacked in a plurality of layers.

Here, the conductive polymer is CMC (carboxymethyl cellulose), PEDOT-PSS (poly(3,4-ethylenedioxythiophene) polystyrene sulfonate), PEDOT-PANI (poly(3,4-ethylenedioxythiophene) polyaniline), EDOT (Ethylenedioxythiophene), CNT (Carbon) Nano Tube), PVDF (polyvinylidene fluoride), PEDOT: PPy, and may include one or more selected from the group consisting of SBR resin.

In particular, CMC (carboxymethyl cellulose), PEDOT-PSS (poly(3,4-ethylenedioxythiophene) polystyrene sulfonate), or PEDOT-PANI has higher electrical conductivity than other conductive polymers. Therefore, they facilitate the movement of electrons between the color-changing materials, and accordingly, the ionic conductivity increases, and as a result, the effect of increasing the color-changing speed can be obtained.

A method of forming the electrode layer is not particularly limited, and a known method may be used without limitation. For example, the electrode layer may be provided by forming an electrode material including transparent conductive oxide particles on a transparent glass substrate in the form of a thin film through a sputtering process.

The thickness of the electrode layer is not particularly limited, but considering flexibility or interlayer adhesion, for example, the transparent electrode may have a thickness in the range of 1 nm to 1 μm. The electrode layer may have a thickness of 1 nm or more, 150 nm or more, or 300 nm or more within the range of 1 nm to 1 μm. The upper limit of the thickness of the electrode layer is not particularly limited, but the electrode layer may have a thickness of 800 nm or less, 700 nm or less, or 500 nm or less to realize low resistance.

In addition, the electrode layer may have a transmittance of 70% to 95% of visible light. Visible light in the present application may mean light having a wavelength range of about 350 nm to 750 nm, and more specifically, may mean light having a wavelength of 550 nm.

Meanwhile, the electrochromic layer may include an electrochromic material whose color is changed by being colored or discolored by application of a voltage. The electrochromic layer may include at least one metal oxide selected from the group consisting of Cr, Mn, Fe, Co, Ni, Li, Rh, Ir, Ti, Nb, Mo, V, Ta and W.

In one example, the electrochromic layer may include one or more oxides selected from the group consisting of Cr, Mn, Fe, Co, Ni, Li, Rh, and Ir, which are oxidative electrochromic materials. The oxidative discoloration material refers to a material exhibiting low light transmittance while discoloration (coloring) occurs during an oxidation reaction according to voltage application. The oxidative discoloration material exhibits high light transmittance while discoloration (discoloration) occurs during the reduction reaction.

In one example, the electrochromic layer may include one or more oxides selected from the group consisting of Ti, Nb, Mo, V, Ta, and W, which are reducing electrochromic materials. The reductive discoloration material refers to a material that exhibits low light transmittance while discoloration (coloring) occurs during a reduction reaction according to voltage application. The reducible color-changing material exhibits high light-transmitting properties while discoloration (discoloration) occurs during an oxidation reaction.

In addition, the electrochromic layer may be an electrochromic device satisfying the following [General Formula 1]. :

[General formula 1]

ΔT(%) = T ₁ - T ₂ ≥ 30

In [General Formula 1], T ₁ is the transmittance of visible light when the electrochromic layer is discolored, and T ₂ is the transmittance of visible light when the electrochromic layer is colored.

In the present application, "transmittance" means transmittance with respect to visible light of the electrochromic layer having the layer configuration described in the present application. Transmittance can be measured using known devices and methods. For example, a known device such as a Solidspec 3700 or an ellipsometer may be used to measure the transmittance of the electrochromic layer. In this case, the visible light may refer to light having a wavelength range of about 350 nm to 750 nm, and more specifically, light having a wavelength of 550 nm.

The electrochromic layer according to the present application has a difference in transmittance for visible light when the light transmittance of the device is bleached and the transmittance for visible light when the light transmittance of the device is colored in [General Formula 1]. is configured to satisfy at least 30% or more. More specifically, it may be 35% or more, 40% or more, 45% or more, 50% or more, 55% or more, or 60% or more.

On the other hand, the electrolyte layer may be configured to provide electrolyte ions involved in the electrochromic reaction. In this case, the electrolyte ions are inserted into the electrochromic layer and may be monovalent cations that can participate in the color change reaction, for example, H ⁺ , Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , or Cs ⁺ . .

The type of electrolyte is not particularly limited. For example, the electrolyte layer may be any one of a liquid electrolyte, a gel-polymer electrolyte, or an inorganic solid electrolyte. The electrolyte layer may be used in the form of one layer or a film so as to be laminated together with an adjacent layer configuration.

Here, the electrolyte layer may include at least one of poly(ethylene glycol) methyl ether methacrylate (PEGMA) and poly(ethylene glycol) methyl ether dimethacrylate (PEGDMA).

The electrolyte layer may have a thickness of 30 μm to 200 μm, and a light transmittance of 70% to 95% for visible light. More specifically, the electrolyte layer may have a thickness of 30 μm to 50 μm, 30 μm to 100 μm, 50 μm to 100 μm, 50 μm to 200 μm, 100 μm to 200 μm, or 150 μm to 200 μm, and , the light transmittance in visible light may be in the range of 75% to 95%, 85% to 95%, 90% to 95%, 70% to 80%, or 70% to 90%. In this case, the visible light may refer to light having a wavelength range of about 350 nm to 750 nm, and more specifically, light having a wavelength of 550 nm.

Meanwhile, the inorganic coating layer may include a silane (Si _n H _2n+2 )-based inorganic material. More specifically, vinyl silane coupling agents such as vinyl trichlorosilane, vinyl tris (2-methoxyethoxy) silane, vinyl triethoxy silane, and vinyl trimethoxy silane; (meth)acrylic silane compounds such as 3-methacryloxypropyltrimethoxysilane and 3-methacryloxypropyltriethoxysilane; epoxy-based silane compounds such as 2-(3,4-epoxycyclohexyl)-ethyltrimethoxysilane, 3-glycidyloxypropyltrimethoxysilane, and 3-glycidyloxypropylmethyldiethoxysilane; N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, 3 -amino silane compounds, such as aminopropylmethyldiethoxysilane, 3-aminopropyltrimethoxysilane, and 3-aminopropyltriethoxysilane; and/or an alkoxy-based silane compound such as 3-chloropropyltrimethoxysilane and 3-chloropropyltriethoxysilane may be used, but the above-listed materials are not particularly limited.

In the present application, due to problems such as adhesion, wetting, or electrolyte thickness occurring at the interface between the electrochromic layer and the electrolyte layer, the current flowing in the device flows through the electrolyte when the device is driven ( In order to prevent current leakage), the inorganic coating layer including a silane (Si _n H _2n+2 )-based inorganic material is disposed between the electrochromic layer and the electrolyte layer.

A method of coating the inorganic coating layer is not particularly limited. For example, it may be coated by spin coating, dip coating, spray coating, gravure coating, flow coating or bar coating. Preferably, it may be coated through a step of heat treatment after application to the electrochromic layer by spin coating.

The thickness of the inorganic coating layer may be in the range of 15 nm to 20 nm. More specifically, 15 nm to 19.5 nm, 15 nm to 19 nm, 15 nm to 18.5 nm, 15 nm to 18 nm, 15 nm to 17.5 nm, 15 nm to 17 nm, 15.5 nm to 20 nm, 15.5 nm to 19.5 nm, 15.5 nm to 19 nm, 15.5 nm to 18.5 nm, 15.5 nm to 18 nm, 15.5 nm to 17.5 nm, 15.5 nm to 17 nm, 16 nm to 20 nm, 16 nm to 19.5 nm, 16 nm to 19 nm, 16 nm to 18.5 nm, 16 nm to 18 nm, 16 nm to 17.5 nm, 16 nm to 17 nm, 16.5 nm to 20 nm, 16.5 nm to 19.5 nm, 16.5 nm to 19 nm, 16.5 nm to 18.5 nm, 16.5 nm to 18 nm, 16.5 nm to 17.5 nm, or 16.5 nm to 17 nm.

The surface roughness (thickness uniformity, surface roughness) Ra value according to the ISO4287 standard of the inorganic coating layer may be in the range of 0.4 nm to 0.6 nm. More specifically, 0.43 nm to 0.6 nm, 0.46 nm to 0.6 nm, 0.4 nm to 0.57 nm, 0.43 nm to 0.57 nm, 0.46 nm to 0.57 nm, 0.4 nm to 0.54 nm, 0.43 nm to 0.54 nm, 0.46 nm to 0.54 nm, 0.4 nm to 0.5 nm, 0.43 nm to 0.5 nm, or 0.46 nm to 0.5 nm.

On the other hand, the ion storage layer formed on the opposite surface of the electrolyte layer facing one surface of the inorganic coating layer balances the charge with the electrochromic layer during a reversible oxidation/reduction reaction for discoloration of the electrochromic material. It may mean a layer formed for More specifically, the ion storage layer may refer to a layer capable of participating in a color change reaction because charged particles necessary for the redox reaction of the electrochromic layer may be inserted or desorbed.

The ion storage layer may include one or more metal oxides selected from the group consisting of Cr, Mn, Fe, Co, Ni, Li, Rh, Ir, Ti, Nb, Mo, V, Ta and W.

In one example, in order to balance the charge between the electrochromic layer and the ion storage layer, a complementary electrochromic material may be used for each of the electrochromic layer and the ion storage layer. Accordingly, when the electrochromic layer contains an oxidative color-changing material such as lithium nickel oxide (LiNiOx), the ion storage layer may include a reducing color-changing material such as tungsten oxide (WOx).

The thickness of the ion storage layer is not particularly limited. For example, the thickness of the ion storage layer may be 1 μm or less. Specifically, the thickness may be 50 nm or more, 100 nm or more, 150 nm or more, or 200 nm or more, and may be 900 nm or less, 700 nm or less, 500 nm or less, or 400 nm or less.

In addition, the inorganic coating layer may further include an inorganic coating layer disposed between the ion storage layer and the electrode layer formed on the opposite surface of the electrolyte layer facing one surface of the inorganic coating layer.

The inorganic coating layer may include a silane (Si _n H _2n+2 )-based inorganic material. A detailed description of the inorganic coating layer will be omitted since it is the same as the inorganic coating layer described above.

Hereinafter, the present application will be described in detail through examples. However, the protection scope of the present application is not limited by the examples described below.

Experimental Example 1: Measurement of current leakage of electrochromic device

For the electrochromic device manufactured as follows, leakage current was measured.

Example 1: Preparation of an electrochromic device coated with an inorganic coating layer

As a silica-based precursor, a silane compound, tetraethyl orthosilicate (TEOS) was dissolved in an aqueous methanol solution at a ratio of TEOS:MeOH:H ₂ O=1:20:8 to cause a hydrolysis reaction.

Next, HCl was added as a catalyst to induce a condensation reaction in the precursor to prepare a sol-type coating solution.

Thereafter, the sol-type coating solution prepared as described above was coated on the electrochromic layer by spin coating at 500 rpm for 30 seconds, and then dried in an oven at 150° C. for 3 minutes.

1 schematically illustrates the electrochromic device 10 according to an embodiment of the present application described above. In Example 1 of the present application, the conductive polymer PEDOT-PSS (poly(3,4-ethylenedioxythiophene) polystyrene sulfonate) was used as the electrode layer 11, and WO ₃ (tungsten oxide) was used as the electrochromic layer 12 for reductive discoloration. As the material, TEOS was used as the inorganic coating layer 13 , and a poly(ethylene glycol) methyl ether methacrylate (PEGMA)-based polymer electrolyte was used as the electrolyte layer 14 .

Comparative Example 1: The same electrochromic device as in Example 1 was prepared except that the inorganic coating layer was not coated.

2 is a graph of measuring the current per hour (normal current) of the electrochromic device according to an embodiment of the present application, and is a graph of measuring the normal current of Example 1 and Comparative Example 1. Referring to FIG.

The leakage current may be measured as a steady-current value of the electrochromic element. The steady current means the value of the current flowing in the device immediately before the opposite voltage is applied when a constant voltage is applied to sufficiently move ions in the direction of each electrode (energy storing).

Referring to FIG. 2 , a saturated current value (saturation current, the maximum current that does not increase any more when a voltage above a certain level is applied) is measured in a specific section when a voltage is applied, and this value is defined as a steady current value. . In the present application, 3V was applied when color by reduction occurred, and 0V was applied when discoloration by oxidation occurred.

Referring to FIG. 2 , it can be seen that the electrochromic device coated with the inorganic coating layer of the present application (Example 1) has a reduced leakage current compared to the electrochromic device that is not coated with the inorganic coating layer (Comparative Example 1).

Therefore, according to the electrochromic device of the present application described above, an inorganic coupling agent is coated on the interface between the electrolyte layer and the electrochromic layer to maintain the color change characteristics, and when a voltage is applied, the current flowing in the electrochromic device leaks through the electrolyte It is possible to reduce unnecessary power consumption by effectively controlling and reducing the Furthermore, it is possible to improve the stability and durability of the electrochromic device and increase the lifespan.

10: electrochromic element
11: electrode layer
12: electrochromic layer
13: inorganic coating layer
14: electrolyte layer

Claims (15)

electrode layer; an electrochromic layer formed on the electrode layer; an electrolyte layer formed on the electrochromic layer; and
An inorganic coating layer disposed between the electrochromic layer and the electrolyte layer,
The inorganic coating layer reduces or prevents leakage current flowing through the electrolyte,
The inorganic coating layer includes a silane (Si _n H _2n+2 )-based inorganic material,
An electrochromic device having a surface roughness (thickness uniformity) Ra value of 0.4 nm to 0.6 nm according to ISO4287 standard of the inorganic coating layer. The method of claim 1,
The electrochromic device further comprising an ion storage layer formed on the opposite surface of the electrolyte layer facing one surface of the inorganic coating layer, and an electrode layer.
3. The method according to claim 1 or 2,
The electrode layer is an electrochromic device that is a transparent electrode or a reflective electrode.
4. The method of claim 3,
The transparent electrode may include a transparent conductive compound (TCO); conductive polymers; silver nanowires; And Electrochromic device comprising at least one selected from the group consisting of a metal mesh.
5. The method of claim 4,
The transparent electrode has a thickness in the range of 1 nm to 1 μm, and transmittance for visible light is in the range of 70% to 95% of the electrochromic device.
The method of claim 1,
The electrochromic layer is an electrochromic device comprising at least one metal oxide selected from the group consisting of Cr, Mn, Fe, Co, Ni, Li, Rh, Ir, Ti, Nb, Mo, V, Ta and W.
The method of claim 1,
The electrochromic layer is an electrochromic device satisfying the following general formula 1:
[General formula 1]
ΔT(%) = T ₁ - T ₂ ≥ 30
In [General Formula 1], T ₁ is the transmittance of visible light when the electrochromic layer is discolored, and T ₂ is the transmittance of visible light when the electrochromic layer is colored.
The method of claim 1,
The electrolyte layer is an electrochromic device comprising at least one selected from the group consisting of a liquid electrolyte, a gel-polymer electrolyte, and an inorganic solid electrolyte.
The method of claim 1,
The electrolyte layer has a thickness of 30 μm to 200 μm, and an electrochromic device having a light transmittance of 70% to 95% for visible light.
delete The method of claim 1,
The thickness of the inorganic coating layer is 15nm to 20nm electrochromic device.
delete 3. The method of claim 2,
The ion storage layer is an electrochromic device comprising at least one metal oxide selected from the group consisting of Cr, Mn, Fe, Co, Ni, Li, Rh, Ir, Ti, Nb, Mo, V, Ta and W.
3. The method of claim 2,
An electrochromic device further comprising an inorganic coating layer disposed between the ion storage layer and the electrode layer.
delete

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