KR20180107866A - Electrochromic device, display including the same and method of preparing transmissivity changeable device - Google Patents

Abstract

Provided is an electrochromic device capable of driving at low voltages which comprises: an operating electrode; an opponent electrode; a nanostructure layer including an inorganic nanoparticle positioned on one surface of the operating electrode facing the opponent electrode; and an electrolyte including viologen and ferrocene.

Description

TECHNICAL FIELD [0001] The present invention relates to an electrochromic device, a display device including the electrochromic device, and a method of manufacturing the electrochromic device. BACKGROUND ART [0002] Electrochromic devices,

A display device including the same, and a method of manufacturing an electrochromic device.

An electrochromic device (ECD) is a device using an electrochromic phenomenon that changes light transmittance by using a substance that is colored by an electric oxidation-reduction reaction when a voltage is applied. The most successful products utilizing the above-mentioned electrochromic devices include a rearview mirror for automatically controlling the glare of light at the rear at night, a smart window (smart window, which can be automatically controlled according to the intensity of light) window. The smart window has a characteristic that it changes into a darker color tone in order to reduce the amount of light when the amount of solar radiation is large, and the energy saving efficiency is changed by changing to a bright color tone on a cloudy day. In addition, development is being continuously carried out for applications such as electric sign boards or e-book displays.

An embodiment of the present invention provides an electrochromic device capable of increasing a change in light transmittance and capable of driving at a low voltage.

Another embodiment of the present invention provides a display device including the electrochromic device.

Another embodiment of the present invention provides a method of manufacturing an electrochromic device, which is simple in manufacturing process, has increased light transmittance variation, and can be driven at a low voltage.

In one embodiment of the present invention, the working electrode; A counter electrode; A nanostructure layer including inorganic nanoparticles positioned on one surface of the working electrode facing the counter electrode; And an electrolyte comprising viologen and ferrocene.

In another embodiment of the present invention, the electrochromic device; And a voltage applying means electrically connected to the electrochromic device.

In another embodiment of the present invention, there is provided a method of manufacturing a semiconductor device, comprising: forming inorganic nanoparticles on a working electrode to form a nanostructure layer; A counter electrode; Adding viologen and ferrocene to the solvent to prepare a liquid electrolyte;

Assembling the working electrode having the nanostructured layer formed thereon such that the nanostructure layer faces the counter electrode and disposing the liquid electrolyte between the working electrode and the counter electrode and sealing the liquid electrolyte between the working electrode and the counter electrode A method of manufacturing an electrochromic device is provided.

The electrochromic device can be fabricated with a simpler manufacturing process, in which a change in light transmittance is increased, low voltage driving is possible, and the like.

1 schematically shows a cross section of an electrochromic device according to an embodiment of the present invention.
2 is a cross-sectional view of an electrochromic device according to another embodiment of the present invention, which schematically shows the behavior of an electrolyte when a voltage is applied and when a voltage is not applied.
3 shows a cross section of the display device according to another embodiment of the present invention.
4 is a graph showing the light transmittance of the electrochromic device of Example 1 when a voltage is applied and when no voltage is applied.
5 is a graph showing the light transmittance of the electrochromic device of Comparative Example 1 when a voltage is applied and when no voltage is applied.
6 is a graph showing the light transmittance of the electrochromic device of Comparative Example 2 when a voltage is applied and when no voltage is applied.
7 is a graph showing the light transmittance of the electrochromic device of Comparative Example 3 when a voltage is applied and when no voltage is applied.
FIG. 8 is a graph showing a comparison between Example 1 of FIG. 4 and Comparative Example 2 of FIG.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art to which the present invention pertains. The present invention may be embodied in many different forms and is not limited to the embodiments described herein.

In order to clearly illustrate the present invention, parts not related to the description are omitted, and the same or similar components are denoted by the same reference numerals throughout the specification.

In the drawings, the thicknesses are enlarged to clearly indicate layers and regions. In the drawings, for the convenience of explanation, the thicknesses of some layers and regions are exaggerated.

Hereinafter, the formation of any structure in the "upper (or lower)" or the "upper (or lower)" of the substrate means that any structure is formed in contact with the upper surface (or lower surface) of the substrate However, the present invention is not limited to not including other configurations between the substrate and any structure formed on (or under) the substrate.

In one embodiment of the invention,

Working electrode;

A counter electrode;

A nanostructure layer including inorganic nanoparticles positioned on one surface of the working electrode facing the counter electrode; And

Electrolytes including viologen and ferrocene;

And an electrochromic device.

Fig. 1 schematically shows a cross-section of the electrochromic device 100. Fig. 1, the electrochromic device 100 includes a working electrode 10; A nanostructure layer 30, an electrolyte 40, and a counter electrode 20.

The light transmittance of the electrochromic device 100 may be changed depending on whether a voltage is applied or not.

The electrochromic device 100 can realize a higher light transmittance change.

As the electrochromic device 100 realizes a higher light transmittance change, it can be driven at a low voltage and thus has a low power consumption.

The working electrode 10 and the counter electrode 20 may each independently be a transparent conductive metal oxide.

Specifically, the transparent conductive metal oxide may be selected from the group consisting of indium tin oxide (ITO), indium zinc oxide (IZO), fluorine doped tin oxide (FTO), aluminum doped zinc oxide, and combinations thereof .

The nanostructured layer 30 may be formed by coating the inorganic nanoparticles on one surface of the working electrode 10.

1, the nanostructured layer 30 is formed of a layer in which the inorganic nanoparticles 30a are stacked, and is formed into a structure including pores as a space between the inorganic nanoparticles 30a is formed do.

The nanostructure layer 30 acts to facilitate the movement of electrons from the working electrode 10 toward the electrolyte 40 when a voltage is applied.

The average particle diameter of the inorganic nanoparticles 30a may be 5 nm to 20 nm. If the average particle diameter of the inorganic nanoparticles 30a is less than 5 nm, there is a limit to the implementation of the paste due to intergranular agglomeration, and when the inorganic nanoparticles 30 are larger than 20 nm, the surface area is reduced.

The inorganic nanoparticles 30a may be a transparent semiconductor material.

In one embodiment, the inorganic nanoparticles (30a) may include one selected from the group consisting of TiO _2, ITO, and combinations thereof.

The thickness of the nanostructured layer 30 may be between 1 탆 and 10 탆. If the thickness of the nanostructured layer 30 is less than 1 m, the surface area of the nanostructured layer 30 is reduced. If the thickness of the nanostructured layer 30 exceeds 10 m, the transmittance of the nanostructured layer 30 is lowered.

The electrolyte (40) may be liquid, molten salt or solid.

In one embodiment, the electrolyte 40 can be a liquid electrolyte 40, and specifically, the liquid electrolyte 40 can include one selected from the group consisting of dimethylsulfoxide, acetonitrile, and combinations thereof. have. Dimethylsulfoxide is highly soluble in ferrocene.

The electrolyte (40) is a liquid electrolyte (40), and the solvent and the phase may include the viologen dissolved in a solvent and the ferrocene.

When a voltage is applied to the working electrode 10, at least some of the viols contained in the electrolyte 40 adhere to the surface of the inorganic nanoparticles 30a of the nanostructure layer 30, May be present in the electrolyte 40 in a dissolved state.

The viologen may have a terminal group introduced therein, and the terminal group may be attached to the surface of the inorganic nanoparticle 30a by chemical bonding or chemisorption.

The terminal group may be a functional group capable of chemically bonding with the surface of the inorganic nanoparticles 30a, and any functional group capable of being introduced into the virosene may be used without limitation. Specifically, the viologen may be one in which a substituent of -PO ₃ H ₂ is introduced.

Specifically, in the above viologen, all of the two nitrogen atoms of 4,4'-bipyridine may be substituted with a substituent of -PO ₃ H ₂ .

The viologen is a dye material which is discolored when an electron is received. When the voltage is applied, the viologen is partially adhered to the surface of the inorganic nanoparticles 30a and discolored, and the remaining part of the viologen is discolored in the electrolyte 40 as it is. Since the viologen is discolored among the electrolyte 40, the electrochromic device can realize a lower light transmittance upon discoloration.

2 schematically shows movement of the biologen when a voltage is applied to the electrochromic device 200. Fig.

2 shows a state in which the viologen 50 and the ferrocene 60 in the electrolyte 40 are dissolved and dispersed and the right part shows a state in which a part of the viologen 50 is in a nano- Is attached to the surface of the inorganic nanoparticles 30a of the structure layer 30 and the remaining part of the inorganic nanoparticles 30a is dissolved and remains in the electrolyte 40. The viologen is discolored in this voltage application state.

The viologen 50 may be contained in the electrolyte 40 in an amount of 10 mM to 50 mM.

If the viologen 50 is included in the electrolyte 40 out of the range, it may be difficult to achieve a predetermined photochromic rate. The electrolyte 40 includes the ferrocene 60 as well as the viologen 50.

The ferrocene 60 can increase the electrical conductivity and the ion conductivity of the electrolyte 40, thereby helping the color change of the biologen 50.

The ferrocene 60 may be contained in an amount of 5 to 50% by weight of the electrolyte 40.

If the ferrocene 60 is contained in an amount of less than 5% by weight of the electrolyte 40, it may be difficult to achieve a predetermined photochromism.

In the electrochromic devices 100 and 200, the viologen 50 is included in the electrolyte 40, and when a voltage is applied, a part of the viologen 50 present in the electrolyte 40 reacts with the inorganic nanoparticles 30a. However, it is not manufactured by coating the surface of the inorganic nanoparticles (30a) separately at the time of manufacturing the nanostructured layer. Therefore, there is an advantage that a separate process for coating virosens may not be performed during the manufacturing process of forming the nanostructured layer.

Since the process is shortened, the viologen 50 can be discolored even in the electrolyte 40, so that the light transmittance can be further reduced when a voltage is applied. Accordingly, the change in light transmittance of the electrochromic devices 100 and 200 can be increased.

Specifically, the change in the light transmittance before and after the voltage application of the electrochromic devices 100 and 200 can be 70% or more under the condition of applying the voltage of -1.5 V.

The electrochromic devices 100 and 200 may additionally include a known configuration for further increasing the change in light transmittance in addition to the above-described configuration. However, since the electrochromic devices 100 and 200 can attain a high light transmittance change as described above, rather than including an additional structure for further increasing the light transmittance change, the light transmittance change is 70% Or more.

For example, when a counter-material layer is additionally formed on one surface of the counter electrode 20 facing the working electrode 10, the counter material helps smooth the transfer of electrons, The oxidation and reduction reaction can be performed more efficiently electrochemically, and the change in light transmittance can be further improved. The counter material may be inorganic nanoparticles of a metal oxide, and specific examples thereof include antimony doped tin oxide (ATO) and the like.

As the counter electrode material layer is not formed on the counter electrode 20, the loss of light transmittance caused by the counter material layer can also be prevented. Therefore, it is possible to further improve the decolorization transmittance when the voltage is not favorable, and furthermore, the change in the light transmittance can be further increased.

Specifically, the electrochromic devices 100 and 200 may have a light transmittance of 60% to 77% when the voltage is not applied.

As described above, since the electrochromic devices 100 and 200 can attain a high light transmittance change, a change in the light transmittance can be achieved without forming a layer containing the counter material in the counter electrode 20, % Or more.

In one embodiment, the counter electrode 20 may be directly exposed to the electrolyte 40 without forming additional layers on one side opposite the working electrode 10.

In another embodiment of the present invention, the electrochromic device; And a voltage application means electrically connected to the electrochromic device.

3 shows a display device 300 formed by connecting power to the working electrode 10 and the counter electrode 20 of the electrochromic device.

In another embodiment of the present invention,

Coating inorganic nanoparticles on the working electrode to form a nanostructure layer;

Adding viologen and ferrocene to the solvent to prepare a liquid electrolyte;

Assembling the working electrode having the nanostructured layer formed thereon so that the nanostructure layer faces the counter electrode and injecting the liquid electrolyte between the working electrode and the counter electrode and sealing the liquid electrolyte;

The present invention also provides a method of manufacturing an electrochromic device.

The above-described electrochromic device can be produced by the above-described method for producing an electrochromic device.

Since the method of manufacturing the electrochromic device does not further include a step of coating the inorganic nanoparticles with a substance such as an electrochromic dye after the step of forming the nanostructured layer as described above, And cost reduction is possible.

As described above, the method of manufacturing an electrochromic device can also realize a high light transmittance change without forming a counter material layer on one side of the counter electrode, so that the step of coating the counter material is omitted So that the manufacturing process can be shortened.

In the method of manufacturing an electrochromic device, the working electrode, the counter electrode, and the liquid electrolyte have been described in detail above.

The inorganic nanoparticles may be TiO ₂ particles.

The viologen may be one in which a substituent of -PO ₃ H ₂ is introduced.

The electrolyte may be a liquid electrolyte comprising one selected from the group consisting of dimethylsulfoxide, acetonitrile, and combinations thereof.

Hereinafter, examples and comparative examples of the present invention will be described. The following embodiments are only examples of the present invention, and the present invention is not limited to the following embodiments.

( Example )

Example  One

TiO ₂ is prepared by mixing titanium tetraisopropoxide (TTIP) with a mixed solution of ethanol and water, adjusting the pH by using nitric acid (HNO ₃ ), and adding TiO ₂ Were synthesized. 10 wt% of ethyl cellulose and 2.5 wt% of lauric acid were added to the synthesized TiO ₂ nanoparticles, and the amount of terpineol added was adjusted to prepare a coating paste having an appropriate viscosity. The prepared paste was coated on a film by doctor blade method and heat treated at 500 ° C to prepare a porous TiO ₂ film.

TiO ₂ nanoparticles (average particle size 7 nm) were coated on the fluorine doped tin oxide (FTO) working electrode to a thickness of 5 μm to prepare a working electrode having a nanostructure layer formed of TiO ₂ particles on one surface.

On the other hand, an FTO counter electrode was prepared.

Separately, a liquid electrolyte was prepared by mixing 20 mM viologen and 0.1 M ferrocene having an ethyl group and - (CH ₂ ) ₂ PO (OH) ₂ as a terminal substituent in dimethylsulfoxide (DMSO).

The working electrode and the counter electrode were assembled by separating the working electrode and the counter electrode so that the nanostructure layer of the working electrode faced the counter electrode. The prepared liquid electrolyte was injected as an electrolyte solution and sealed to manufacture an electrochromic device.

Comparative Example  One

First, a working electrode and a counter electrode were prepared in the same manner as in Example 1. The solution was dissolved in methanol at a concentration of 20 mM of viologen having an ethyl group and - (CH ₂ ) ₂ PO (OH) ₂ as a terminal substituent, and the working electrode thus prepared was carried thereon for 18 hours to prepare viologen coated TiO ₂ particles A working electrode having a formed nanostructure layer on one side was prepared.

On the other hand, a counter electrode coated with antimony doped tin oxide (ATO) nanoparticles on one side of the FTO counter electrode was prepared.

The working electrode and the counter electrode were assembled apart from each other so that the coating surface of the nanostructure layer of the working electrode and the coating surface of the ATO nanoparticle of the counter electrode faced each other. An electrolytic solution of 0.1M ferrocene mixed in dimethylsulfoxide (DMSO) And sealed to prepare an electrochromic device.

Comparative Example  2

A working electrode of the FTO and a counter electrode of the FTO were prepared.

Separately, a liquid electrolyte was prepared by mixing 20 mM viologen and 0.1 M ferrocene having an ethyl group and - (CH ₂ ) ₂ PO (OH) ₂ as a terminal substituent in dimethylsulfoxide (DMSO).

The working electrode and the counter electrode were assembled by separating the working electrode and the counter electrode so that the nanostructure layer of the working electrode faced the counter electrode. The prepared liquid electrolyte was injected as an electrolyte solution and sealed to manufacture an electrochromic device.

Comparative Example  3

First, a working electrode and a counter electrode were prepared in the same manner as in Example 1. The solution was dissolved in methanol at a concentration of 20 mM of viologen having an ethyl group and - (CH ₂ ) ₂ PO (OH) ₂ as a terminal substituent, and the working electrode thus prepared was carried thereon for 18 hours to prepare viologen coated TiO ₂ particles A working electrode having a formed nanostructure layer on one side was prepared.

On the other hand, a counter electrode coated with antimony doped tin oxide (ATO) nanoparticles on one side of the FTO counter electrode was prepared.

The working electrode and the counter electrode were assembled apart from each other so that the coating surface of the nanostructure layer of the working electrode and the coating surface of the ATO nanoparticle of the counter electrode faced each other, and 0.1 M lithium perchlorate (LiClO ₄ ) Was injected and sealed to prepare an electrochromic device.

evaluation

Experimental Example  One: Light transmittance

Voltages were applied to the electrochromic devices prepared in Example 1 and Comparative Example 1, respectively, and the transmittance and the transmittance were measured by UV / Vis Spectrum (PerkinElmer, Lambda 35) when the voltage was not applied and the voltage was applied.

4 is a graph showing the light transmittance of Example 1. Fig.

5 is a graph showing a measurement of the light transmittance of Comparative Example 1. Fig.

The electrochromic device of Example 1 was evaluated for light transmittance at 550 nm. In Table 1, the light transmittance at the time of voltage application (change in color) and the change in light transmittance at the time of voltage uncolored (discoloration), ΔT (%) are calculated and described.

division Transmittance (%) ΔT (%) Example 1 Decolorization (0V) 73.719 71.588 Discoloration (-1.5V) 2.131

The electrochromic devices of Comparative Examples 1 to 3 were evaluated for light transmittance at 550 nm.

6 is a graph showing the light transmittance of Comparative Example 2 measured.

7 is a graph showing the light transmittance of Comparative Example 3 measured.

In Table 2, the difference in light transmittance at 550 nm upon application of voltage (discoloration) and the difference in light transmittance at 550 nm when no voltage is applied (discoloration) and ΔT (%) are calculated and described.

division Transmittance (%) ΔT (%) Comparative Example 1 Decolorization (0V) 59.387 - Discoloration (-3V) 4.113 55.274 Discoloration (-1.5V) 20.712 38.675 Comparative Example 2 Decolorization (0V) 76.133 - Discoloration (-1.5V) 53.717 22.416 Comparative Example 3 Decolorization (0V) 63.218 Discoloration (-3V) 8.72 54.498 Discoloration (-1.5V) 50.368 12.85

From the results shown in Tables 1 and 2, the light transmittance in Example 1 was 73.719% at the time of decolorization, and the light transmittance at the time of decolorization in Comparative Example 1 was higher than 59.387%, thereby increasing the light transmittance at the time of decolorization and discoloration. This is because, in Example 1, the ATO layer was not formed on the counter electrode, thereby increasing the light transmittance upon decolorization. In addition, in Example 1, since a change in light transmittance is increased, sufficient color change can proceed even at a low color change voltage, so that it can be understood that low voltage drive is possible.

Experimental Example  2

The voltage of -1.5 V was applied to the electrochromic devices prepared in Example 1 and Comparative Example 2, respectively, and the transmittance and the transmittance were measured using a UV / Vis Spectrum (PerkinElmer, Lambda 35) when the voltage was not applied.

8 is a graph showing a comparison between the light transmittance (discoloration) and the light untransmitted (discolored) light transmittance at -1.5 V voltage application in Example 1 of FIG. 4 and Comparative Example 2 of FIG.

Table 3 shows the measured values of light transmittance at 550 nm for the electrochromic devices of Example 1 and Comparative Example 2. In Table 3, the difference (? T (%)) between the light transmittance at the time of voltage application (discoloration) and the light transmittance at the time of no voltage change (discoloration) is calculated and described.

decolorization% % Discoloration (-1.5V) ΔT% Example 1 74.686 1.453 73.232 Comparative Example 2 76.133 53.717 22.416

As a result of measurement of the voltage unfavorable visible light transmittance and the change of the light transmittance even when a voltage of -1.5 V was applied, it was confirmed that the light transmittance was excellent in Example 1. However, Comparative Example 2 in which the TiO ₂ nanostructure layer was not formed, , The light transmittance change was low even though it was prepared by dissolving the viologen compound used in the electrolyte.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, Of the right.

10: working electrode
20: counter electrode
30: nanostructure layer
30a: inorganic nanoparticles
40: electrolyte
50: Biologen
60: Ferrocene
100, 200: electrochromic device
300: display device

Claims (18)

Working electrode;
A counter electrode;
A nanostructure layer including inorganic nanoparticles positioned on one surface of the working electrode facing the counter electrode; And
Electrolytes including viologen and ferrocene;
And an electrochromic device.
The method according to claim 1,
Wherein the working electrode and the counter electrode are each independently a transparent conductive metal oxide
Electrochromic device.
3. The method of claim 2,
Wherein the transparent conductive metal oxide is selected from the group consisting of indium tin oxide (ITO), indium zinc oxide (IZO), fluorine doped tin oxide (FTO), aluminum doped zinc oxide,
Electrochromic device.
The method according to claim 1,
The inorganic nanoparticles are transparent semiconductor materials
Electrochromic device.
The method according to claim 1,
The inorganic nano-particles comprising one selected from the group consisting of TiO _2, ITO, and combinations thereof
Electrochromic device.
The method according to claim 1,
Wherein the nanostructured layer is a layer in which the inorganic nanoparticles having an average particle diameter of 5 nm to 20 nm are stacked and includes pores formed in the space between the inorganic nanoparticles
Electrochromic device.
The method according to claim 1,
Wherein the thickness of the nanostructured layer is 1 占 퐉 to 10 占 퐉
Electrochromic device.
The method according to claim 1,
Wherein the viologen is contained in an amount of 10 mM to 50 mM in the electrolyte
Electrochromic device.
The method according to claim 1,
The Biology halogen is a substituent of -PO ₃ H ₂ introduced
Electrochromic device.
The method according to claim 1,
At the time of voltage application, at least a portion of the viologen is attached to the surface of the inorganic nanoparticles of the nanostructured layer, and at least another portion is present dissolved in the electrolyte
Electrochromic device.
11. The method of claim 10,
When the voltage is applied, the viologen attached to the surface of the nanoparticles and the viologen dissolved in the electrolyte are discolored together
Electrochromic device.
The method according to claim 1,
The electrolyte may be liquid, molten salt or solid
Electrochromic device.
The method according to claim 1,
Wherein the electrolyte is a liquid electrolyte comprising one selected from the group consisting of dimethylsulfoxide, acetonitrile, and combinations thereof.
Electrochromic device.
The method according to claim 1,
The counter electrode may be formed on a surface opposite to the working electrode without forming an additional layer,
Electrochromic device.
The method according to claim 1,
Wherein the electrochromic device has a light transmittance of 60% to 77%
Electrochromic device.
An electrochromic device according to any one of claims 1 to 15; And
And voltage applying means electrically connected to the electrochromic device.
Coating inorganic nanoparticles on the working electrode to form a nanostructure layer;
Adding viologen and ferrocene to the solvent to prepare a liquid electrolyte;
Assembling the working electrode having the nanostructure layer and the counter electrode so that the nanostructure layer faces the counter electrode and injecting the liquid electrolyte between the working electrode and the counter electrode and sealing ;
Wherein the electrochromic device further comprises an electrochromic device.
18. The method of claim 17,
Wherein the inorganic nanoparticles comprise TiO ₂
A method of manufacturing an electrochromic device.

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