KR100765120B1 - Electrochromic device with reduced light scattering property and method for preparing the same - Google Patents

Abstract

The present invention relates to an electrochromic device in which light scattering is reduced by adjusting the refractive index of an electrolyte, and a method of reducing light scattering in an electrochromic device by using an electrolyte in which the refractive index is controlled.

Light Scattering, Electrochromic Device, Refractive Index, Electrochromic, Electrochromic Material

Description

Electrochromic device with reduced light scattering property and method for preparing the same}

1 schematically shows an electrochromic device having electrodes coated with an electrochromic material.

FIG. 2A schematically illustrates light scattering that occurs when an electrolyte having an unrefractive index is used in an electrochromic device having an electrode coated with an electrochromic material.

FIG. 2B schematically shows that in an electrochromic device having an electrode coated with an electrochromic material, light scattering is reduced when using an electrolyte having a controlled refractive index.

3 is a graph showing the light scattering characteristics measured using the integrating sphere method of the electrochromic device of the embodiment.

Here, A represents light scattering of air, B represents light scattering of Comparative Example 1 in which the refractive index of the electrolyte is not controlled, and 3c represents light scattering when the compound of Formula 1c is added as an electrolyte regulator (Example 1). And 3a show light scattering when the compound of Chemical Formula 1a is added as an electrolyte regulator (Example 2).

4 shows that a tungsten oxide electrochromic material formed by etching nano silica particles included in a tungsten oxide thin film is applied to an electrode.

FIG. 5 is a view in which the electrochromic material is coated on a transparent electrode of a glass substrate so that light is transmitted when the power is cut off (A) and is discolored when the power is applied to serve as a smart window that blocks only light of a specific wavelength. (B) is shown schematically.

6 is a schematic diagram showing a structure of an electrochromic device in which an electrochromic material is disposed on an upper substrate of a mirror surface to form an electrochromic mirror .

Figure 7 is a graph showing the results of measuring the coloration and decolorization time as the operating characteristics of the electrochromic devices prepared in Comparative Example 1 and Example 1. (A: Comparative Example 1, B: Example 1)

<Short description of symbols>

1, 5: substrate

2, 4: electrode

3: electrochromic material

6: electrolyte

7: power

8: light

The present invention relates to an electrochromic device in which light scattering is reduced by adjusting the refractive index of an electrolyte, and a method of reducing light scattering in an electrochromic device by using an electrolyte in which the refractive index is controlled.

Electrochromic is a phenomenon in which the color changes depending on the potential of the applied electric field. By using the electrochromic phenomenon, electro-optical switch devices such as electrochromic devices, information storage devices, and solar cells can be manufactured. In particular, as a electrochromic device (ECD) using such electrochromic properties, smart windows or electrochromic mirrors, which are used for controlling light transmittance and reflectivity in windows and mirrors, are currently used.

Electrochromic materials can be divided into inorganic electrochromic materials (Inorganic EC material), organic electrochromic material (Organic EC material) and organic-inorganic hybrid discoloration material. Representative inorganic electrochromic materials include WO ₃ , NiO _x H _y , Nb ₂ O ₅ , V ₂ O ₅ , TiO ₂ , MoO ₃ , and organic electrochromic materials. -Inorganic hybrid material is a type of material in which viologen is chemically adsorbed onto anatase TiO ₂ nanoparticles.

The electrochromic material is generally used in the form of a thin film coated on the electrode or dispersed in the electrolyte. Among them, in particular, the electrochromic material in the form of a metal oxide has a nanoparticle structure, and they are often used by coating or applying an electrode in the form of a nanoparticle film. Nanoparticle films of these metal oxides have been applied in various fields such as electrochromic and photoelectric power generation.

Meanwhile, the electrochromic materials may be used by surface treatment with other electrochromic materials, and metal oxides without electrochromic properties may be surface treated with electrochromic materials.

Nanoparticle films formed by metal oxides surface-treated with electrochromic materials are very useful in applications that require optical modulation, such as smart windows or autosensing rear mirrors in automobiles. For example, WO-A-97 / 35227 and WO-A-98 / 35267 also show examples of electrochromic devices including nanostructured metal oxide films and electrodes modified by chemisorption of electrochromic compounds. The electrochromic device using a nanostructured metal oxide film modified by chemisorption of the electrochromic compound as an electrode has an advantage that the surface area of the electrode is very wide compared to the general electrochromic device, so that the driving speed is fast and no afterimages remain during decolorization.

However, the electrochromic device has a structure in which an electrolyte is filled between both electrodes, and there is a problem in that light scattering occurs due to a difference in refractive index between the electrochromic material and the electrolyte.

In particular, titanium dioxide (TiO ₂ ) having a refractive index of about 2.4 or tungsten trioxide (WO ₃ ) having a refractive index of 1.68 is mainly used as metal oxide nanoparticles, and α-butyrolactone having a refractive index of 1.436 (mp: -45 ° C, bp) is used as an electrolyte. : 204 DEG C), they have a difference in refractive index. As shown in FIG. 2A, light scattering due to the difference in refractive index occurs. Such light scattering does not affect an electrochromic device having an opaque background color such as an electronic paper, but may be a problem in an electrochromic device having a mirror surface such as a transparent or electrochromic mirror such as a smart window. That is, such light scattering phenomenon causes a problem of reducing the sharpness of the image passing through or reflecting the electrochromic device when using a metal electrode used as a transparent electrode or a mirror surface as a back electrode such as a smart window or an automatic discolored rear mirror.

As such, it is necessary to suppress light scattering, in particular light scattering between the electrochromic material and the electrolyte, in order to improve the image clarity in the electrochromic device.

Accordingly, the present inventors have studied to increase the sharpness of the phase transmitted through the electrochromic device having an electrode treated with the electrochromic material or the electrochromic device in which the electrochromic material is dispersed in the electrolyte, thereby adjusting the refractive index of the electrolyte. The present invention has been accomplished by knowing that light scattering can be reduced.

Accordingly, the present invention aims to reduce light scattering by adjusting the refractive index of the electrolyte to increase the sharpness of the phase transmitted through the electrochromic device.

In addition, an object of the present invention is to provide an electrochromic device in which light scattering is minimized using an electrolyte having a refractive index controlled and a method of manufacturing the device.

The present invention also provides a method of controlling the refractive index of the electrochromic device by adjusting the refractive index of the electrolyte.

The present invention provides an electrochromic device having an electrode treated with an electrochromic material, using an electrolyte to which a refractive index modifier is added.                     

The present invention, for example, as shown in Figure 1, the front substrate (1); A first electrode 2 formed on the front substrate; An electrochromic material layer 3 formed on the first electrode; A rear substrate 5 disposed to face the front substrate; A second electrode (4) formed in a direction toward the front substrate from the rear substrate surface; And an electrolyte 6 filled between the electrodes, wherein the electrolyte is provided with an electrochromic device in which a refractive index regulator having a different refractive index from that of the electrolyte is mixed.

On the other hand, in the case of an electrochromic device in which the electrochromic material is distributed in the electrolyte, the electrochromic material will be dispersed in the electrolyte unlike FIG. 1.

In the electrochromic apparatus, the front substrate and the rear substrate are spaced apart from each other to form a space between the first electrode formed on the front substrate and the second electrode formed on the back substrate, and the electrolyte is filled in the space. When the front substrate portion including the first electrode and the back substrate portion including the second electrode are in contact with each other, the electrolyte is filled with a predetermined gap for filling the electrolyte, instead of sealing the entire surface with the bonding material. do. After the electrolyte is filled, the gap may be filled to seal the electrolyte.

In the electrochromic device according to the present invention, light scattering can be reduced by adjusting the refractive index of the electrolyte. As the difference between the refractive index value of the electrolyte and the refractive index value of the electrochromic material decreases, light scattering is reduced. Preferably, the refractive index of the electrolyte and the refractive index of the electrochromic material are adjusted to 1.0 or less, which is effective to prevent light scattering.

In general, since the refractive index of the electrochromic material is larger than that of the electrolyte, the refractive index is adjusted by increasing the refractive index of the electrolyte.                     

Accordingly, the present invention provides an electrochromic device capable of minimizing light scattering by using an electrolyte having an increased refractive index by addition to a refractive index regulator.

The present invention also provides a method of reducing light scattering of an electrochromic device by increasing the refractive index of the electrolyte.

In addition, the present invention provides a refractive index regulator that can be added to the electrolyte of the electrochromic device to reduce light scattering.

In the electrochromic device according to the present invention, when the ionic liquid or the ionic liquid gel is used as the electrolyte, the light scattering reduction effect is excellent. The effect of this reduction in light scattering can also be seen in solid electrolytes.

Examples of the electrolyte usable in the present invention include γ-buryrolactone , ethylene carbonate , propylene carbonate, dimethyl carbonate, and the like, but the electrolyte is not limited thereto. Preferably, γ-butyrolactone mixed with lithium bisimide and ferrocene may be easily used.

The refractive index adjusting agent usable in the electrochromic device according to the present invention may be used as long as it is a material capable of reducing the difference in refractive index between the electrolyte and the electrochromic material and can be dissolved or incorporated in the electrolyte. In addition, a material without color and high transparency is more preferable as the refractive index regulator. It is preferable that the modifier is not electrochemically active, and therefore, as long as it is soluble in the electrolyte, the modifier may exhibit the effect of the refractive index regulator regardless of the type of the electrolyte or the type of the refractive index regulator.

In general, since the refractive index of the electrolyte is lower than that of the electrochromic material, the refractive index regulator according to the present invention will be a material having a larger refractive index than the electrolyte.

In general, organic molecules have a refractive index of 1.42 to 1.50, and when a large number of atoms such as S, P, Br, etc. are included in a molecule, organic molecules have a high refractive index of 1.55 to 1.61. In addition, when the monomolecular high refractive material is polymerized, the refractive index increases (see Bai Yang et al. J. Appl. Polym. Sci. 2000, 75 , 1474).

Therefore, preferably, a compound of a single molecule or a polymer having a refractive index of 1.5 or more including Br, S, and P can be used as the refractive index regulator according to the present invention.

Specifically, the refractive index regulator suitable for the present invention, tetrabromobisphenol A (Formula 1a), 2,4,6-tribromophenyl acrylate (Formula 1b), 2,4,6-tribromophenyl ethoxyacrylate (Formula 1c) or 2,2'6,6 bromine compounds such as' tetrabromobisphenol A ethoxylate (1 EO / phenol) diacrylate (Formula 1d); Examples include sulfur-based materials such as thiodiglycol diacrylate (Formula 1e) and polymers of these materials. In addition, the refractive index control agent may be a solid material that is dissolved in an electrolyte such as diphenyl sulfide (Formula 1f) or triphenyl phosphate (Formula 1g) as well as a liquid. In addition, 2,5-dimercapto-1,3,4-thiadiazole represented by the following Chemical Formula 1h and 2-aminophenyl disulfide represented by the Chemical Formula 1i may be used. Of course, the compounds can be used in combination.                     

(tetrabromobisphenol A, n = 1.64)

(2,4,6-tribromophenyl acrylate, n = 1.587)

(2,4,6-tribromophenyl ethoxyacrylate, n = 1.564)

(2,2'6,6'-tetrabromobisphenol A ethoxylate (1 EO / phenol) diacrylate, n = 1.564)

(thiodiglycol diacrylate, n = 1.511)

(diphenyl sulfide, n = 1.632)

(triphenyl phosphate, n = 1.568)

(2,5-dimercapto-1,3,4-thiadiazole)                     

(2-aminophenyl disulfide)

As described above, the refractive index of the electrolyte to which the refractive index regulator with high refractive index is added increases compared to before the addition, and the difference in refractive index with the metal oxide nanoparticle thin film is reduced, so that the light goes straight and the scattering of light is reduced and the image is much clearer. Done.

The amount of the refractive index control agent used depends on the refractive index of the electrochromic material and the refractive index of the electrolyte. The smaller the difference between the refractive index of the electrochromic material and the refractive index of the electrolyte, the better the light scattering reduction effect, and in particular, since the difference in refractive index is preferably 1.0 or less, those skilled in the art can adjust the refractive index regulator so that the difference in refractive index can be within 1.0 or less. You can adjust the amount.

In general, the refractive index regulator may be contained in the electrolyte at a concentration of 0.5 M or less. Naturally, the amount is controlled according to the refractive index of the refractive index regulator and the refractive index of the electrolyte. However, if the amount of the refractive index regulator is too large, there is a problem in that the performance of the electrolyte is reduced, so it is preferable that the amount of the refractive index regulator not exceed the concentration of 0.5M in the electrolyte as described above. Preferably, the refractive index regulator is contained in the electrolyte at a concentration of 0.2M or less, more preferably at a concentration of 0.1M or less.

Those skilled in the art will be able to appropriately select and use the refractive index regulator and its amount so that the difference between the refractive index of the electrochromic material and the refractive index of the electrolyte is as small as possible while not increasing the amount of the refractive index regulator.

On the other hand, the electrochromic material used in the electrochromic device according to the present invention can be used without limitation as long as the material can change color by the change of the electric field. For example, as an electrochromic material in the form of a metal oxide, TiO ₂ , WO ₃ , SnO ₂ , MoO ₃ , ZnO ₂ , NiO ₂ , FeO ₃ , IrO ₃ , RuO ₂ , NiO _x H _y , Nb ₂ O ₅ , V ₂ O ₅ , TiO _2, and the like may be used, and polyaniline may be used as the organic electrochromic material. In addition, the surface of the material having no electrochromic properties may be modified with a material having electrochromic properties to be used as an electrochromic material. On the other hand, by modifying the electrochromic material may be used to improve the electrochromic properties. For example, an electrochromic material may be used in which the surface of a metal oxide having electrochromic properties is treated with a compound having electrochromic properties to improve its color change rate.

As a specific example, in the case of the above-described electrode oxide, WO ₃ may form nanostructures such as nano holes, and TiO ₂ may be treated with a viologen compound to improve its discoloration rate. Substances that improve electrochromic properties by being applied to the surface of metal oxides, such as viologen compounds, are also called electrochromic dyes. In particular, electrochromic dyes self-assemble on metal oxide nanoparticle surfaces during chemical modification. It will form a self-assembled mono-layer.

As the electrochromic dye material applicable for improving the properties of the electrochromic material used in the electrochromic device according to the present invention, there is preferably a viologen compound. In particular, 2-((α '-(4' ''-N, N-dimethylylridinium) -4 ''-α-)-4,4'-dipyridinium) -ethylphosphonicacid trichloride salt represented by the following Chemical Formula 2 (DMAP- VP) or bis- (2-phosphonoethyl) -4,4'-bipyridinium dichloride (PVP). Of course, compounds having other electrochromic properties can also be used.

(DMAP-VP)

(PVP)                     

As the electrode material, any material having electrical conductivity can be used without limitation. For example, a metal, a metal oxide, or an organic material may be used as the electrode material. Those skilled in the art may select and use a required electrode according to the use of the electrochromic device.

For example, when the electrochromic device according to the present invention is used for transmitting light such as a smart window, a transparent electrode should be used, and if a light should be reflected like an autochromic mirror, a mirror surface electrode should be used. . As the transparent electrode, indium tin oxide (ITO) or fluorine doped tin oxide (FTO) may be mainly used, and as the mirror electrode, a metal mirror surface such as silver or chromium, or a metal oxide such as antimony-doped tin oxide (ATO) Nanoparticle membranes can be used.

The electrochromic material is applied or coated on at least one electrode, and is applied by a method such as screen printing, sol-gel method or doctor blading.

The electrode to which the electrochromic material is applied is generally a transparent electrode. In an electrochromic device having mirror characteristics, the mirror surface electrode is generally disposed on the side opposite to the electrode to which the electrochromic material is applied. For example, on the side opposite to the electrode to which the electrochromic material is applied, the transparent substrate can be used as a smart window, and the metal electrode can be applied as an auto-sensing rear mirror.

The electrodes to which the electrochromic material is applied and the opposite electrodes opposite to each other are bonded to face each other at a predetermined interval. At this time, the electrolyte is injected and sealed by using an inert gas in the vacuum chamber by leaving a part of the adhesive part. After the electrolyte is injected, a part of the adhesive is completely sealed to maintain airtightness.                     

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the present invention is not limited by the following examples or comparative examples.

Comparative Example 1

Anatase-type TiO ₂ was coated on a glass substrate coated with fluorine doped tin oxide (FTO) 25 cm wide and 7 cm long as an electrode, and 24 cm wide and 6 cm long as an electrochromic material. A transparent electrode was prepared by surface modification with '-(4'''-N, N-dimethylylridinium) -4 ''-α-)-4 and 4'-dipyridinium) -ethylphosphonicacid trichloride salt.

Specifically, Ti (O-iPr) ₄ was hydrolyzed to make TiO ₂ nanocrystalline colloidal dispersions. The average particle size of the initially prepared nanocrystals was 7 nm, and autoclave was carried out at 200 ° C. for 12 hours to obtain an average particle size of 12 nm. The solvent was distilled under reduced pressure to obtain a concentration of 160 g / L, and 40 wt% of Carbowax 20000 [which is poly (ethylene oxide) having an average molecular weight of 20000] was added to TiO ₂ to give a high viscosity white titania sol paste. Made. The dough was screen printed onto an ITO transparent electrode using a screen printing method and sintered at a high temperature of 450 ° C. to make a transparent electrode coated with TiO ₂ metal oxide including nanopores.

For surface modification of the TiO ₂ , 2-((α '-(4'''-N, N-dimethylylridinium) -4 ''-α-)-4,4'-dipyridinium) -ethylphosphonicacid at a concentration of 10 mM After dipping the above-mentioned working transparent electrode in 50 ml of trichloride salt (Formula 2) for 30 minutes, washing twice with 50 ml of ethanol and drying at room temperature for 4 hours to complete the transparent electrode coated with electrochromic material. At this time, the thickness of the surface-modified titanium oxide (TiO ₂ ) thin film was 4 μm.

A chromium metal mirror surface was used as a counter electrode of the transparent electrode coated with the electrochromic material. That is, the counter electrode was fabricated by sputtering chromium to a thickness of 200 nm on a washed glass substrate of 25 cm in width and 7 cm in length.

The electrochromic material-coated transparent electrode and the chromium mirror surface electrode were bonded with a thermosetting adhesive to face each other at an interval of 80 μm. At this time, one part of the adhesive part was left about 2 mm to inject the electrolyte. Electrolyte was injected into the bonded electrochromic device using argon gas in a vacuum chamber. The electrochromic device after the electrolyte injection was completely sealed by applying an ultraviolet curable adhesive and irradiating ultraviolet rays with the injection part left for electrolyte injection. The injected electrolyte was a mixture of lithium bisimde 0.2M and ferrocene 0.02M in a γ-butyrolactone solvent with a refractive index of 1.436.

The production characteristics of the electrochromic device was measured at 500nm wavelength and the light scattering characteristics were measured using an Automatic Haze Meter, Model TC-H III DP / K (Tokyo Denshoku Co. Ltd). As a result of measuring the light scattering after the electrolyte injection, the electrolyte scattering degree was measured to 1.5%. For reference, the scattering degree was 2.3% before the electrolyte was injected. This is because light scattering decreases as an electrolyte having a refractive index higher than that of air having a refractive index of 1 is injected.

As a result of measuring the operating characteristics of the electrochromic device manufactured as described above, it was confirmed that the coloring time was about 3 seconds and the decoloring time was about 4 seconds as shown in FIG.

<Example 1>

An electrochromic device was manufactured in the same manner as in Comparative Example 1, except that 2,4,6-tribromophenyl ethoxyacrylate having a refractive index of 1.56 was added to the electrolyte so as to have a concentration of 0.02 M. As described above, light scattering of the electrochromic device using the electrolyte to which the refractive index regulator was added was measured by an automatic haze meter in the same manner as in Comparative Example 1. As a result, scattering was measured at 1.3%.

That is, as compared with the scattering degree of 1.5% (Comparative Example 1) of the electrolyte, the refractive index is not controlled, it can be seen that the transparency is improved by 13% or more when the compound represented by Formula 1c is added as the refractive index regulator. As a result of measuring the operating characteristics of the electrochromic device manufactured as described above, it was confirmed that the coloring time was about 3 seconds and the decoloring time was about 4 seconds as shown in B of FIG. 7. As a result of the measurement, it can be seen that the produced electrochromic device did not reduce the self-coloring rate characteristic even when the refractive index regulator was added.

<Example 2>                     

An electrochromic device was manufactured in the same manner as in Comparative Example 1, except that tetrabromobisphenol A (Formula 1a) having a refractive index of 1.64 was added to the electrolyte so as to have a concentration of 0.02M. As described above, light scattering of the electrochromic device using the electrolyte to which the refractive index regulator was added was measured by an automatic haze meter in the same manner as in Comparative Example 1. As a result, scattering was measured at 1.2%.

That is, as compared with the scattering degree of 1.5% (Comparative Example 1) of the electrolyte having no controlled refractive index, it was found that the transparency was improved by about 20% when the compound represented by Chemical Formula 1a was added as the refractive index regulator. Since the refractive index (1.64) of the compound of Formula 1a is higher than the refractive index (1.56) of the compound of Formula 1c, it can be seen that the scattering degree by the compound of Formula 1a is greater when used at the same concentration.

Comparative Example 2

Electrochromic material by forming nano holes on a tungsten oxide thin film coated with a sol-gel coating method having a width of 24 cm and a length of 6 cm on a glass substrate coated with 25 cm and 7 cm fluorine doped tin oxide (FTO) as an electrode. This coated transparent electrode was prepared.

Specifically, according to the method described in Korean Patent Application Publication No. 2003-0037100 (Application No. 2001-0068201), a tungsten oxide electrochromic material thin film in which nano holes are formed in a sol-gel coated tungsten oxide thin film is formed. It was. At this time, the thickness of the tungsten oxide thin film was 300 nm.                     

As a counter electrode of the metal oxide nanoparticle electrode, a metal mirror surface made of silver (Ag) was used. Specifically, silver was deposited by sputtering on a washed glass substrate having a width of 25 cm and a length of 7 cm to produce a metal mirror surface. The same electrolyte was filled in the same manner as in Comparative Example 1.

Operation and light scattering properties of the electrochromic device were measured in the same manner as in Comparative Example 1. As a result, the scattering degree was 1.4%.

<Example 3>

An electrochromic device was manufactured in the same manner as in Comparative Example 2, except that tetrabromobisphenol A (Formula 1a) having a refractive index of 1.64 was added to the electrolyte so as to have a concentration of 0.02 M. As a result of measuring light scattering of the electrochromic device using the electrolyte to which the refractive index regulator was added, the scattering degree was measured to be 1.25%. As compared with the scattering degree of the electrolyte having no controlled refractive index of 1.4% (Comparative Example 2), it was found that the transparency was improved by about 10%.

The degree of improvement in scattering degree was small compared with the results of Examples 1 and 2, since the tungsten oxide thin film used was relatively thinner than the thickness of the titanium oxide thin films of Examples 1 and 2, so that light scattering was not large and thus relatively low. The decrease in scattering degree was also not significant.

Comparative Example 3                     

As an electrochromic material, an electrochromic device was manufactured in the same manner as in Comparative Example 1 except that a nickel oxide thin film having a thickness of 2 m was formed by a sol-gel method using nickel oxide particles having a size of 10 to 35 nm. Light scattering of the electrochromic device using the same electrolyte as in Comparative Example 1 was measured in the same manner as in Comparative Example 1. As a result, the scattering degree was determined to be 1.55%.

<Example 4>

An electrochromic device was manufactured in the same manner as in Comparative Example 3, except that 2,4,6-tribromophenyl ethoxyacrylate having a refractive index of 1.56 was added to the electrolyte so as to have a concentration of 0.02M.

The light scattering of the electrochromic device using the electrolyte to which the refractive index regulator was added was measured in the same manner as in Comparative Example 1, and the scattering degree was 1.3%. That is, it can be seen that the transparency is improved when compared with the electrolyte scattering degree of 1.55% for which the refractive index is not controlled by the electrolyte to which the compound represented by Chemical Formula 1c is added.

The above embodiment relates to an electrochromic mirror. When the transparent electrode is used without using a metal mirror surface as a counter electrode, the electrochromic glass may be manufactured. In the embodiment for the electrochromic glass, light scattering reduction effect can be obtained as in the electrochromic mirror.

By using the present invention, it is possible to reduce the light scattering degree of the electrochromic device by adjusting the refractive index of the electrolyte of the electrochromic device, thereby improving the sharpness of the image passing through the electrochromic glass or the electrochromic mirror.

Claims (16)

Front substrate; A first electrode formed on the front substrate; A rear substrate disposed to face the front substrate; A second electrode formed from the rear substrate side toward the front substrate; An electrochromic material present between the first electrode and the second electrode; And An electrolyte filled between the electrodes; In the electrochromic device comprising a, The electrolyte is mixed with a refractive index regulator having a different refractive index and the refractive index of the electrolyte, the refractive index control agent is characterized in that the compound containing at least one atom selected from the group consisting of Br, S and P or a mixture thereof Discoloration device. The electrochromic device of claim 1, wherein the second electrode is a metal mirror surface or a transparent electrode. The electrochromic device according to claim 1, wherein the electrolyte is made of an ionic liquid or an ionic liquid gel. The electrochromic device of claim 1, wherein the refractive index control agent is a material having a refractive index larger than that of the electrolyte. The electrochromic device according to claim 1, wherein the refractive index adjusting agent has a refractive index of 1.5 or more. delete The electrochromic device of claim 1, wherein the refractive index control agent comprises at least one compound selected from the group consisting of compounds represented by Formulas 1a to 1i: [Formula 1a]

(tetrabromobisphenol A, n = 1.64) [Formula 1b]

(2,4,6-tribromophenyl acrylate, n = 1.587) [Formula 1c]

(2,4,6-tribromophenyl ethoxyacrylate, n = 1.564) [Formula 1d]

(2,2'6,6'-tetrabromobisphenol A ethoxylate (1 EO / phenol) diacrylate, n = 1.564) [Formula 1e]

(thiodiglycol diacrylate, n = 1.511) [Formula 1f]

(diphenyl sulfide, n = 1.632) [Formula 1g]

(triphenyl phosphate, n = 1.568) [Formula 1h]

(2,5-dimercapto-1,3,4-thiadiazole) Formula 1i]

(2-aminophenyl disulfide) The electrochromic device of claim 1, wherein the electrochromic material is selected from the group consisting of TiO ₂ , WO ₃ , SnO ₂ , MoO ₃ , ZnO ₂ , NiO, FeO ₃ , IrO _3, and RuO ₂ . The electrochromic device of claim 8, wherein the electrochromic material is surface-modified by a viologen compound. The method of claim 9, The viologen compound is 2-((α '-(4' ''-N, N-dimethylylridinium) -4 ''-α-)-4,4'-dipyridinium) -ethylphosphonicacid trichloride represented by Chemical Formula 2 below. salt (DMAP-VP) or bis- (2-phosphonoethyl) -4,4'-bipyridinium dichloride (PVP) represented by the following formula (3). [Formula 2]

(DMAP-VP) [Formula 3]

(PVP) Front substrate; A first electrode formed on the front substrate; A rear substrate disposed to face the front substrate; A second electrode formed from the rear substrate side toward the front substrate; An electrochromic material disposed between the first electrode and the second electrode; And an electrolyte filled between the electrodes; a method of reducing light scattering of an electrochromic device comprising: A refractive index regulator having a refractive index higher than that of the electrolyte is further added to the electrolyte, wherein the refractive index regulator comprises at least one atom selected from the group consisting of Br, S, and P, and the compound having a refractive index of 1.5 or more or a mixture thereof Characterized in that the method. delete The method of claim 11, wherein the refractive index adjusting agent comprises at least one compound selected from the group consisting of compounds represented by Formulas 1a to 1i: [Formula 1a]

(tetrabromobisphenol A, n = 1.64) [Formula 1b]

(2,4,6-tribromophenyl acrylate, n = 1.587) [Formula 1c]

(2,4,6-tribromophenyl ethoxyacrylate, n = 1.564) [Formula 1d]

(2,2'6,6'-tetrabromobisphenol A ethoxylate (1 EO / phenol) diacrylate, n = 1.564) [Formula 1e]

(thiodiglycol diacrylate, n = 1.511) [Formula 1f]

(diphenyl sulfide, n = 1.632) [Formula 1g]

(triphenyl phosphate, n = 1.568) [Formula 1h]

(2,5-dimercapto-1,3,4-thiadiazole) Formula 1i]

(2-aminophenyl disulfide) A refractive index regulator for an electrolyte in an electrochromic device, comprising a compound having a refractive index of 1.5 or more having at least one atom of Br, S, and P. 15. The refractive index modifier of claim 14, wherein the compound is selected from the group consisting of compounds represented by Formulas 1a to 1i. [Formula 1a]

(tetrabromobisphenol A, n = 1.64) [Formula 1b]

(2,4,6-tribromophenyl acrylate, n = 1.587) [Formula 1c]

(2,4,6-tribromophenyl ethoxyacrylate, n = 1.564) [Formula 1d]

(2,2'6,6'-tetrabromobisphenol A ethoxylate (1 EO / phenol) diacrylate, n = 1.564) [Formula 1e]

(thiodiglycol diacrylate, n = 1.511) [Formula 1f]

(diphenyl sulfide, n = 1.632) [Formula 1g]

(triphenyl phosphate, n = 1.568) [Formula 1h]

(2,5-dimercapto-1,3,4-thiadiazole) Formula 1i]

(2-aminophenyl disulfide) 15. The refractive index regulator of claim 14, wherein the electrolyte is an electrolyte of an electrochromic device including a pair of substrates, a pair of electrodes facing each other, an electrochromic material, and an electrolyte filled between the electrodes. .

Images