KR102669249B1 - Photo-curable electrochromic material, electrochromic device comprising same, and method for manufacturing same - Google Patents

Abstract

The present invention relates to a photocurable electrochromic material with improved surface hardness and capable of micrometer-sized patterning, an electrochromic device containing the same, and a method for manufacturing the same. The electrochromic material of the present invention is a polyhedral oligomer silcet containing a vinyl group. Polyhedral Oligomeric Silsesquioxane (POSS) derivatives have a network structure formed by cross-linking with a compound represented by the following formula (1).
[Formula 1]
[X] _n
In Formula 1, R ₁ is selected from C0, methylene group, phenyl group, thiophene group, acetylene group, vinyl group, cyanovinyl group, phosphonic group or carbazole group, R ₂ is C1 to C10 alkylene group, It is selected from a phenyl group or a thiophene group, n is an integer of 2 to 4, and X is an anion.

Description

Photo-curable electrochromic material, electrochromic device comprising same, and method for manufacturing same {Photo-curable electrochromic material, electrochromic device comprising same, and method for manufacturing same}

The present invention relates to a photocurable electrochromic material with improved surface hardness and capable of micrometer-sized patterning, an electrochromic device containing the same, and a method of manufacturing the same.

Electrochromism refers to a phenomenon in which a reversible color change occurs when an electrochemical oxidation or reduction reaction occurs in a high electrode material. Electrochromic devices refer to devices that exhibit electrochromic effects when voltage is applied, and new color-changing materials are continuously being developed to apply these electrochromic devices to displays and smart windows.

In particular, the demand for display development is increasing significantly due to the development of cutting-edge technologies such as self-driving cars, augmented reality, virtual reality, and the Internet of Things. Recently, electricity has been developed to meet specific requirements such as low power, lightweight, high transparency, and deformability. Next-generation displays based on electrochemical devices (ECDs) are being developed.

These electrochemical devices (ECDs) can also be used as smart windows that block harmful ultraviolet rays, and have advantages such as low-voltage operation, simple manufacturing process, and user-controllable characteristics when applying various potential biases. Additionally, the application of electrochemical devices (ECDs) to anti-glare mirrors, camouflage devices, and electronic paper technologies has recently been expanding in the industrial market.

Conventional electrochemical devices (ECDs) have generally used a liquid electrolyte containing a metal salt in a liquid solvent. However, this type of electrolyte has limitations such as leakage and low stability. Therefore, research on solid electrolytes including gel polymer electrolytes (GPEs) and solid polymer electrolytes (SPEs) has been conducted recently.

Thermal curing method is an efficient method for generating high ionic conductivity for charge transfer and viscosity of gel polymer electrolytes, but it requires significant heat and long curing times, and has the disadvantage of low productivity, which negatively affects low-cost commercialization.

Meanwhile, inorganic metal oxides, metal complexes, conductive polymers, and viologens are being used as electrochromic materials (ECMs). However, most inorganic metal oxides and metal complexes provide only a single color change, and conductive polymers suffer from slow response times and poor cycling stability when exposed to heat and sunlight. Additionally, viologen-based electrochemical devices have the disadvantage of low coloring efficiency and short cycle life.

Therefore, there is a need to develop electrochromic materials that can be applied to displays and smart windows with high optical contrast, coloring efficiency, and low cost, have high surface hardness, and are capable of micro-sized patterning.

One object of the present invention is to provide an electrochromic material capable of expressing various colors, improving surface strength, and enabling micrometer-sized patterning, an electrochromic device containing the same, and a method of manufacturing the same.

The electrochromic material according to an embodiment of the present invention is a polyhedral oligomeric silsesquioxane (POSS) derivative containing a vinyl group cross-linked by a compound represented by the following formula (1) to form a network structure. It is characterized by

[Formula 1]

[X] _n

In Formula 1, R ₁ is selected from C0, methylene group, phenyl group, thiophene group, acetylene group, vinyl group, cyanovinyl group, phosphonic group or carbazole group, R ₂ is C1 to C10 alkylene group, is selected from a phenyl group or a thiophene group, n is an _integer of ₂ to 4, _and

In one embodiment, the compound represented by Formula 1 may include one or more compounds selected from the compounds of Formulas 1-1 to 1-3 below.

[Formula 1-1]

[X] ₂

[Formula 1-2]

[X] ₂

[Formula 1-3]

[X] ₄

In Formulas 1-1 to 1-3, X is the same as Formula 1.

In one embodiment, the compounds of Chemical Formulas 1-1 to 1-3 each express three primary colors of blue, red, and green, and a secondary color and a secondary color by mixing two or more colors. It can appear black.

Specifically, when the compounds of Formula 1-1, Formula 1-2, and Formula 1-3 are included in a molar ratio of 1:1:1, black color may be expressed.

Meanwhile, in order to increase the surface hardness and ionic conductivity of the electrochromic material, the electrochromic material of the present invention contains a polyhedral oligomeric silsesquioxane (POSS) derivative containing a vinyl group, and is represented by the following formula (2) It can be.

[Formula 2]

In Formula 2, POSS is polyhedral oligomeric silsesquioxane (POSS), and R ₃ is a C1 to C10 alkylene group, phenyl group, thiophene group, acetylene group, vinyl group, cyanovinyl group, phosphide. It is selected from a phonic group or a carbazole group, and m is an integer of 1 to 8.

The polyhedral oligomeric silsesquioxane (POSS) derivative represented by Formula 2 forms a cross-link with the compound represented by Formula 1, and the electrochromic material of the present invention forms a network by forming such cross-links. It may have a structure that forms . Therefore, the film containing the electrochromic material of the present invention has improved surface hardness due to the network structure, and can be patterned in various structures, enabling detailed information to be transmitted.

Meanwhile, an electrochromic device according to another embodiment of the present invention includes first and second conductive substrates, and an electrochromic layer disposed between the first and second conductive substrates, and the electrochromic layer is according to the present invention. It may contain electrochromic materials. (see Figure 1)

In one embodiment, the electrochromic material may be included in an ionic gel, and the ionic gel may include a polymer matrix, an ion conductive material, and an anode material.

In one embodiment, the polymer matrix is not particularly limited, but includes poly(ethylene glycol) diacrylate (PEG-DA), polyurethane (PU) and its derivatives, and polyvinyl alcohol (polyvinyl alcohol). alcohol, PVA), polyvinyl butyral (PVB), polyvinylidene fluoride (PVDF) and its derivatives, and polymethyl methacrylate (PMMA). can do.

In one embodiment, the ion conductive material is not particularly limited, but includes 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (BMIM-TFSI), 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMIM- It may contain at least one selected from room temperature ionic liquids including TFSI) and similar substances, or lithium salts having various counter ions.

In one embodiment, the anode material is not particularly limited, but may include ferrocene and its derivatives, or hydroquinone and its derivatives.

In one embodiment, the electrochromic layer of the electrochromic device is preferably formed as a single layer, but to increase the hardness of the surface of the electrochromic layer, an ion conductive layer may be additionally formed on the electrochromic layer.

Meanwhile, a method of manufacturing an electrochromic device according to another embodiment of the present invention includes a polyhedral oligomeric silsesquioxane (POSS) derivative containing a vinyl group, a compound represented by Formula 1 above, on a first conductive substrate. , forming an electrochromic layer by applying an ionic gel composition containing a polymer matrix, an ion conductive material, an anode material, a solvent, and an initiator, and placing a second conductive substrate on the electrochromic layer and then UV curing it. Includes steps.

In one embodiment, the compound represented by Formula 1 may include one or more compounds selected from compounds represented by Formulas 1-1 to 1-3.

In one embodiment, the compounds of Chemical Formulas 1-1 to 1-3 each express three primary colors of blue, red, and green, and a secondary color and a secondary color by mixing two or more colors. It can appear black.

Specifically, when the compounds of Formula 1-1, Formula 1-2, and Formula 1-3 are included in a molar ratio of 1:1:1, black color may be expressed.

Meanwhile, in order to increase the surface hardness and ionic conductivity of the electrochromic device, the electrochromic layer includes a polyhedral oligomeric silsesquioxane (POSS) derivative containing the vinyl group, and can be represented by the formula (2) there is.

Since the polyhedral oligomeric silsesquioxane (POSS) derivative represented by Formula 2 contains a photocurable functional group (vinyl group), photocuring performance can be improved when forming an electrochromic layer of an electrochromic device. , may be cross-linked with the compound represented by Formula 1 through photocuring to form a network structure. Accordingly, the electrochromic device of the present invention has the advantage of improved surface hardness and the ability to provide patterning of various structures, enabling detailed information to be transmitted.

In one embodiment, the polymer matrix included in the ionic gel composition is poly(ethylene glycol) diacrylate (PEG-DA), polyurethane (PU) and its derivatives, and polyvinyl alcohol ( one or more selected from polyvinyl alcohol (PVA), polyvinyl butyral (PVB), polyvinylidene fluoride (PVDF) and its derivatives, and polymethyl methacrylate (PMMA) It includes, and the ion conductive material is 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (BMIM-TFSI), 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMIM-TFSI), and similar room temperature ionic liquids. , or lithium salts having various counterions, and the anode material includes ferrocene and its derivatives, or hydroquinone and its derivatives, and the solvent is It contains at least one selected from acetone, ethanol, methanol, dimethylformamide, dimethyl sulfoxide and dimethylacetamide, and the initiator is dimethoxyphenylacetophenone and derivatives or 2-hydroxy-2-methylpropiophenone and derivatives. It may include, but is not limited to this.

In one embodiment, the first and second conductive substrates may independently use a polyester optical film, a polycarbonate substrate, etc. coated with indium tin oxide, which is a conductive material. A small amount of doping material may be included to improve electrical conductivity.

In one embodiment, the electrochromic layer of the electrochromic element is formed, but is not particularly limited, and spray coating, doctor blade coating, bar coating, etc. may be used. You can.

In one embodiment, in the electrochromic device, the electrochromic layer is preferably formed as a single layer, but in order to increase the hardness of the surface of the electrochromic layer, an ion conductive layer may be additionally formed on the electrochromic layer. .

The electrochromic material according to the present invention has a structure in which a vinyl group-containing polyhedral oligomeric silsesquioxane (POSS) derivative is cross-linked by a vinyl group-containing viologen derivative to form a network, and thus includes this. Electrochromic devices have the advantage of significantly improving surface strength and enabling micrometer-sized patterning to deliver detailed information. In addition, the electrochromic layer containing the electrochromic material of the present invention does not have a leakage problem due to the liquid electrolyte even when applied as a single layer to an electrochromic device.

In addition, the electrochromic device according to the present invention can realize various colors by mixing various electrochromic materials with different structures, and exhibits long-term cycle stability, low driving voltage, high coloring efficiency, and fast switching speed, so it can be applied to smart windows, displays, etc. possible.

1 is a schematic diagram showing an electrochromic device according to an embodiment of the present invention.
Figure 2 shows frontier molecular orbital results obtained through DFT calculation of electrochromic materials according to an embodiment of the present invention.
Figure 3 shows the electrochromic characteristics (cyclic voltammetric curve (a)) of electrochromic devices containing [DA-DPyEV][PF ₆ ] ₂ , [DA-TPyPhV][PF ₆ ] ₄ , and [DAV][PF ₆ ] ₂ - c), a graph showing the spectroelectrochemical curve (d - f), and the transmittance change curve (g - i).
4 ( _a ) _- ( _{c )} show _the coloring _and This is a graph showing the movement stability during electrostatic stepping in the bleached state, and (d) - (f) are graphs showing the transition time required for coloring and bleaching.
Figure 5 is a graph showing the electrochromic characteristics of the electrochromic device according to Example 4 of the present invention.

Hereinafter, various embodiments and experimental examples of the present invention will be described in detail. However, the following examples are only some examples of the present invention, and the present invention should not be construed as being limited to the following examples.

<Manufacturing of electrochromic material>

[Example 1: Synthesis of diallyl-viologen (DAV)]

A mixture of 4,4'-bipyridine (2 g, 2.80 mmol) and allyl bromide (3.87 g, 32.01 mmol) was stirred in acetonitrile at 900°C in a nitrogen atmosphere for 24 hours.

After cooling, the resulting light yellow solid was filtered and washed three times with diethyl ether and acetonitrile. Afterwards, the solid was dried at room temperature to obtain diallyl-viologen (DAV) (1.82 g, yield 91%).

¹ H NMR (DMSO-d ₆ , 25°C, 500 MHz): δ = 9.29 (4H, d, Ar H), 8.74 (4H,d, Ar H), 6.22 (2H, m, N-CH ₂ ), 5.50-5.48 (4H, d, -CH ₂ ), 5.34-5.33 (4H, d, -CH ₂ ). HR-LCMS: C ₁₆ H ₁₈ N ₂ ²⁺ , 238.15 (Theoretical); C ₁₆ H ₁₈ N ₂ ²⁺ , 238.14 (Found)

[Example 2: Synthesis of diallyl-dipyridyl-ethylene cross-linked viologen (DA-DPyEV)]

A mixture of 1,2-di-(4-pyridyl)ethylene (DPyEV) (2 g, 10.97 mmol) and allyl bromide (3.31 g, 27.43 mmol) was added to 20 mL acetonitrile and incubated at 900°C for 24 h in a nitrogen atmosphere. It was stirred.

After cooling, the resulting solid was filtered and washed with acetonitrile and diethyl ether to obtain pure DA-DPyEV (1.76 g, 88%) as a yellow solid.

¹ H-NMR (DMSO-d ₆ , 25°C, 500 MHz): δ = 9.15 (4H, d, Ar-H), 8.35 (4H, d, Ar-H), 8.11 (2H, s, -CH ₂ ), 6.15-6.14 (2H, d, N-CH ₂ ), 5.48-5.43 (4H, m, -CH ₂ -CH ₂ ), 5.24 (4H, d, CH ₂ ). HR-LCMS: C ₁₈ H ₂₀ N ₂ ²⁺ , 264.16 (Theoretical); C ₁₈ H ₂₀ N ₂ ²⁺ , 264.16 (Found)

[Example 3: Synthesis of diallyl-tetrapyridyl-phenyl bridged viologen (DA-TPyPhV)]

A mixture of 4-(2,4,5-tri(pyridin-4-yl)phenyl)pyridine (TPyPhV) (1 g, 2.58 mmol) and allyl bromide (1.40 g, 11.65 mmol) was added to 20 mL acetonitrile and placed under nitrogen atmosphere. It was stirred at 90°C for 48 hours.

After cooling, the resulting solid was filtered and washed with acetonitrile and diethyl ether to obtain pure DA-TPyPhV (1.55 g, 65.5%) as a gray solid.

¹ H-NMR (DMSO-d6, 25°C, 500 MHz): δ = 8.75-8.65 (8H, d, Ar-H), 8.0 (2H, s, Ar-H), 7.96-7.95 (8H, d, Ar-H), 6.06-6.05 (2H, d, CH ₂ ), 5.48-5.43 (4H, m, -CH ₂ -CH ₂ ), 5.24 (4H, d, CH ₂ ). HR-LCMS: C ₃₈ H ₃₈ N ₄ ⁴⁺ , 550.31 (Theoretical); C ₃₈ H ₃₈ N ₄ ⁴⁺ , 549.30 (Found)

Then, the electrochromic materials of Examples 1 to 3 and NH ₄ PF ₆ (about 1:3 molar ratio) were dissolved in 10 mL of methanol and stirred at room temperature for 24 hours. After completion of the reaction, the product was separated by filtration and washed repeatedly with distilled water to remove excess reactants and residual by-products. Then, the solid was obtained by filtration and dried at room temperature to produce [DAV][PF ₆ ] _{2 ,} [DA-DPyEV][PF ₆ ] ₂ and [DA-TPyPhV][PF ₆ ] ₄ , respectively.

<Electrochromic material characteristics>

To understand the electronic structure of vinyl-substituted viologens, molecular orbital diagrams along with HOMO and LUMO levels were obtained by density functional theory (DFT) calculations (see Figure 2).

Referring to Figure 2, insertion of an ethylene moiety between two pyridinium rings and insertion of a phenyl ring between four pyridinium rings were shown to be effective in controlling the energy band gap. The calculated energy band gap of DAV was 2.23 eV, and after insertion of the ethylene moiety (DA-DPyEV), the energy band gap slightly increased to 2.25 eV. The increased bandgap led to an absorption shift to shorter wavelengths, resulting in a red (R) color due to the separation of the two pyridinium rings.

Meanwhile, the phenyl ring (DA-TPyPhV) located between the four pyridinium rings lowered the energy band gap to 1.58 eV. Therefore, when a phenyl ring is inserted, it is absorbed at a longer wavelength and appears green (G).

<Manufacturing of single-layer electrochromic device>

Before manufacturing the electrochromic device, hydroxylation and surface modification of the ITO-glass substrate were performed. Specifically, the ITO glass substrate was sequentially ultrasonically cleaned with deionized water, acetone, and isopropyl alcohol for 20 minutes. After drying, the ITO glass substrate was cut into 2.5 cm Afterwards, the solution was heated to 60°C and maintained for 1 hour, then the hydroxide ITO-glass was rinsed three times with distilled water and dried at room temperature.

Next, for surface modification, triethoxyvinylsilane (10 mg) was used in the prepared UV-curable ion gel composition to form covalent bonds with hydroxide ITO glass after UV curing during electrochromic device fabrication. The film formed due to the covalent bond between triethoxyvinylsilane and hydroxylated ITO-glass can exhibit hardness and strong adhesive properties.

[Example]

A single-layer electrochromic device was manufactured using an ion gel composition containing vinyl group-substituted viologen according to Examples 1 to 3.

The UV curable ion gel composition for red (R), green (G), and blue (B) coloring is [DA-DPyEV][PF ₆ ] ₂ for red (R), [DA-TPyPhV][PF ₆ ] _4, respectively. It contains 200 mg of each for green (G) and [DAV][PF ₆ ] ₂ as a discoloration material for blue (B), methyl-ferrocene (dm-Fc) (10 mg) as an anode material, and PEG-DA. (poly(ethylene glycol)diacrylate) (1 g) as the polymer matrix, [BMIM][TFSI] (1 g) as the ion conductive material, OV-POSS (octavinyl substituted POSS) (50 mg) as the cross-linking additive, and DMPAP (2 -dimethylamino-4-(methyl-phenylamino)-phenol) (5 mg) was prepared by mixing it with acetone as an auxiliary solvent as an initiator.

Meanwhile, for the purpose of obtaining black for privacy protection and solar light modulation, RGB electrochromic material was mixed with the ion gel composition in a 1:1:1 ratio (Example 4).

Afterwards, the mixed solution was stirred at 50°C for 24 hours to form a homogeneous ion gel under dark conditions. Next, the ion gel was coated on the ITO glass substrate with a working area of 2.5 cm by drop-casting, and Surlyn® film with a thickness of 60 ㎛ was used as a spacer. Afterwards, the deposited ion gel was maintained at 75°C for 1 hour to remove the solvent, and the formed gel-like film was covered using another ITO glass.

Next, the electrochromic devices (ECDs) were kept under UV irradiation (Lamp-4, 144 W, peak intensity 365 nm) for curing. In the solid film formed after UV curing for 30 to 60 seconds, the ferrocene and aromatic viologen residues were dissolved to form a slightly yellow film in the bleached state.

[Comparative Example 1]

An electrochromic device was manufactured in the same manner as in the example, except that the ion gel composition was prepared without adding OV-POSS.

[Comparative Example 2]

After preparing an ion gel composition using a discoloring material (OHV-POSS) represented by the following formula (3) as a discoloring material and PVDF-HFP (poly(vinylidene fluoride-co-hexafluoropropylene)) as a polymer material, the ion gel An electrochromic device was manufactured by coating the composition on an ITO substrate, drying it at 60°C for 1 hour, and then covering it with another ITO substrate.

[Formula 3]

[Comparative Example 3]

An electrochromic device was manufactured in the same manner as in Comparative Example 2, except that an ion gel composition was prepared using a color-changing material ([DHV][PF ₆ ] ₂ ) represented by the following formula 4 as a color-changing material.

[Formula 4]

[Comparative Example 4]

An electrochromic device was manufactured in the same manner as in Comparative Example 2, except that an ion gel composition was prepared using the color-changing material [NV][PF ₆ ] ₂ ) represented by the following formula (5).

[Formula 5]

<Evaluation of electrochromic device characteristics>

The driving voltage, permeability difference, color change performance, color change speed, color change stability, surface hardness, color, patterning, and ionic conductivity of the electrochromic devices (Examples 1 to 4 and Comparative Examples 1 to 4) containing electrochromic materials were determined. evaluated. The characteristic evaluation results are summarized in Table 1 below, and the specific characteristic evaluation conditions, methods, and result values for each item are as follows.

Driving
Voltage Transmittance
difference discoloration
Performance discoloration
speed discoloration
stability surface
Hardness Hardening
method patterning
Whether color Example 1 ◎ ○ ○ ○ ◎ 2H light curing ○ blue Example 2 ◎ ○ ○ ◎ ◎ 2H light curing ○ Red Example 3 ○ ◎ ○ ○ ◎ 4H light curing ○ green Example 4 ○ ○ ◎ ◎ ◎ 4H light curing ○ black Comparative Example 1 ◎ ◎ × × △ B light curing △ blue Comparative example 2 ◎ ○ ◎ ◎ ◎ B heat drying × blue Comparative Example 3 ◎ △ × × × B heat drying × blue Comparative Example 4 ◎ × × ◎ × B heat drying × blue

1) Operation voltage (V)

The voltage at which color change occurs was indicated through cyclic voltammetry (CV) measurement. If driving below -1.5 V is possible, it is marked as ◎, if driven above -1.5 V but below -2.0 V, it is marked as ○, and if driven above -2.0 V, it is marked as Х, as shown in Table 1.

Looking at the results in Table 1, the films of Examples 1 to 4 showed redox behavior at low operating voltages due to improved ionic conductivity (see Table 1 and Figure 3).

The CV curves in Figure 3 were obtained by increasing the scan rate at which both the anodic (I _pa ) and cathodic (I _pc ) peak currents increased, showing the linear dependence of I _pa and I _pc on the square root of the scan rate. According to the Randle-Sevcik equation, this result corresponds to a typical one-electron transfer process.

DA-DPyEV(R) film (Example 2) showed fast redox behavior with red coloration at a low operating voltage of -1.5 V (see Figure 3a). The DA-TPyPhV(G) film (Example 3) exhibited redox behavior at -1.8 V with a rapid bleaching and coloring process, resulting in a dark green color (see Figure 3b). Similarly, the DAV(B) film (Example 1) showed reversible blue coloration at -1.5V (see Figure 3c).

The black Example 4 film showed a fast redox process for black coloration at a low operating voltage of -1.8 V (Figure 5a).

2) Transmittance difference (△T)

The transmittance difference at the maximum absorption wavelength was measured, and if the transmittance difference was 80% or more, it was indicated as ◎, if it was 60% to 79%, it was indicated as ○, if it was 40% to 59%, it was indicated as △, and if it was 39% or less, it was indicated as Х, as shown in Table 1.

As a result, the DA-DPyEV(R) film (Example 2) started to change color to red at -0.8 V with simultaneous peaks at 705 nm and 785 nm and a maximum absorption wavelength (λ _max ) at 521 nm in the visible region. did. The transmittance difference (ΔT) for the corresponding wavelengths was 56.7% (521 nm), 74.09% (705 nm), and 79.05% (785 nm), respectively (Figures 3d and 3g). The ethylene group insertion showed absorption at shorter wavelengths than calculated from DFT studies.

Similarly, the DA-TPyPhV(G) film (Example 3) started coloring dark green at -1.1 V with absorption at 400 nm and 621 nm. Additionally, the absorption at 854 nm increased simultaneously in the NIR region. The transmittance difference (ΔT) for the corresponding wavelengths was 80.1% (854 nm), 67.8% (400 nm), and 49.5% (621 nm), respectively (Figures 3e and 3h). The long wavelength absorption for the green coloration is due to the low bandgap obtained by inserting the phenyl ring. Additionally, the NIR absorption originated from the dissociation of four positively charged electron acceptors after incorporating the phenyl moiety. The resulting acceptor-donor-acceptor structure induced a bathochromic shift.

In contrast, the DAV(B) film (Example 1) began to color blue at -0.7 V with a maximum absorption wavelength (λ _max ) of 605 nm and showed a transmittance difference (ΔT) of 65.08% (FIGS. 3f and 3i).

Meanwhile, the black film (Example 4) appeared black by covering the entire visible region at 550 nm (λ _max ) at -1.8V (FIG. 5b).

3) Coloration efficiency (CE)

Color change performance is expressed as the ratio of optical density to applied voltage, and if the coloration effieciency value is >300 cm ² /C, it is ◎, if it is 250 to 299 cm ² /C, it is ○, and if it is 200 to 249 cm ² If it is /C, it is marked with △, and if it is 199 cm ² /C or less, it is marked with ×, as shown in Table 1.

4) Color change speed (switching time, seconds)

The discoloration speed was measured by measuring the time it takes to change between the colored state and the bleached state. If the average discoloration speed is 10 seconds or less, it is ◎, if it is 11 to 20 seconds or less, it is ○, if it is 21 to 30 seconds or less, it is △, and if it is more than 31 seconds, it is ◎. It is denoted by Х and shown in Table 1.

Meanwhile, the kinetic stability behavior of the electrochromic devices was investigated by applying alternating wave potentials between the bleached state and the colored state, and is shown in Figures 4 and 5c.

As a result, the DA-DPyEV(R) film (Example 2) showed an overall transmittance change of 69.09% along with an optical density (ΔOD) of 0.727 and a color efficiency (CE) change of 264.4 cm ² /C during the stability measurement. . The transition times required for the colored and bleached states were measured to be 10 seconds each (Figures 4a and 4d).

Meanwhile, the DA-TPyPhV(G) film (Example 3) showed a total transmittance change of 80.4% with a change in optical density (ΔOD) of 0.716 and a change in color efficiency (CE) of 287.5 cm ² /C. The transition times required for the colored and bleached states were measured and found to be 12 and 14 seconds, respectively (Figures 4b and 4e).

The DAV(B) film (Example 1) had a transmittance change (△T) value of 65.1%, an optical density (△OD) value of 0.762, and a color efficiency (CE) value of 278.2 at 605 nm under 0 to -2V sweeping conditions. It was found to be cm ² /C. The transition times required to reach the colored and bleached states were 13 and 12 s (Figures 4c and 4f).

The black film (Example 4) showed an overall transmittance change of 68.8% along with an optical density (ΔOD) of 1.02 and a color efficiency (CE) change of 341.1 cm ² /C. The transition times required for the colored and bleached states were each measured to be 6.0 s (Figure 5c).

The specific total transmittance change (%), optical density (ΔOD), conversion time required for coloring and bleaching states, and color efficiency (CE) values of Examples 1 to 4 are summarized in Table 2 below.

Viologens Transmittance difference (%) Optical density (OD) Switching time to
colored state(s) Switching time to bleached state (s) Coloration efficiency [DAV][PF ₆ ] ₂ (B)
(Example 1) 65.1 0.762 13 12 278.2 [DA-DPyEV][PF ₆ ] ₂ (R)
(Example 2) 69.9 0.727 10 10 264.4 [DA-TPyPhV][PF ₆ ] ₄ (G)
(Example 3) 80.4 0.716 12 14 287.5 R+G+B=Black
(Example 4) 68.8 1.026 6.0 6.0 341.1

5) Discoloration stability (cyclic stability)

When repeatedly driven, it is evaluated as the driving time that maintains more than 90% of the initial transmittance difference, ◎ for 12,000 seconds or more, ○ for 10,000 to 11,999 seconds or less, △ for 8,000 to 9,999 seconds or less, and × for 7,999 seconds or less. It is indicated in Table 1.

Looking at Table 1, during the long-term stability experiment, the DA-DPyEV(R) (Example 2), DA-TPyPhV(G) (Example 3), and DAV(B) (Example 1) films and the Example 4 film had 3 It exhibited excellent long-term stability for >12000 seconds with less than % initial transmittance loss.

6) Surface hardness

Surface hardness was measured using a pencil hardness measurement method and is shown in Table 1 above.

Referring to Table 1, the films of Comparative Examples 1 to 4 were seriously damaged by B, but the films of Examples 1 to 4 showed excellent surface hardness of up to 4H due to the cross-linked structure due to the presence of POSS molecules inside the polymer matrix. indicated. These results show that OV-POSS provides solid mechanical strength and surface hardness to the ion gel film.

7) Whether patterning

After post-treatment by curing method, immersion in IPA (isopropyl alcohol) and sufficient water washing, if the coating pattern of 10 If no pattern remains, it is marked with △, and if no pattern remains, it is marked with ×, as shown in Table 1.

As a result, in Examples 1 to 4, the coating pattern remained completely intact due to the cross-linked structure of OV-POSS and electrochromic material by UV photocuring, but in Comparative Examples 1 to 4, the coating pattern was The results showed that transformation occurred.

8) Color

When an electrochromic device was manufactured and electrochromic was applied, the color produced was visually determined and shown in Table 1.

As a result of color gamut measurement of the 1931 CIE xy chromaticity diagram, DA-DPyEV(R), DA-TPyPhV(G), and DAV(B) were (0.594, 0.399), (0.284, 0.519), and (0.179, 0.105), respectively. x,y) coordinates were shown, and the single-layer electrochromic device showed 44.6% of the NTSC color gamut.

Meanwhile, the black film of Example 4 achieved black color by applying a reduction potential to an electrochromic device, and L ^* , a ^* , b ^* values were measured at the D65 light source based on the 1976 CIE color diagram. Here, the L ^* , a ^* , and b ^* values correspond to brightness, red-green balance, and yellow-blue balance.

As a result, the (L ^* , a ^* , b ^* ) values of the neutral and fully reduced states were measured as (88.31, 4.63, 12.96) and (13.03, 11.36, 1.24), respectively (Figure 5d). The color difference (E ^* ) was calculated as 76.4 according to the formula below.

9) Ionic conductivity value

Electrochemical impedance spectroscopy (EIS) measurements show that incorporating OV-POSS into PEG-DA and [BMIM][TFSI] yields 4.14 It was confirmed that high ionic conductivity of 10 ^-3 was induced. This shows that incorporating POSS into the polymer matrix improves anion mobility and increases ionic conductivity. As a result, thermal and electrochemical stability and ion transport capacity are improved.

Although the present invention has been described above with reference to preferred embodiments, those skilled in the art can make various modifications and changes to the present invention without departing from the spirit and scope of the present invention as set forth in the following patent claims. You will understand that it is possible.

Claims (15)

An electrochromic material having a network structure in which a polyhedral oligomeric silsesquioxane (POSS) derivative containing a vinyl group is cross-linked by a compound represented by the following formula (1):
[Formula 1]
[X] _n
In Formula 1,
R ₁ is selected from C0, methylene group, phenyl group, thiophene group, acetylene group, vinyl group, cyanovinyl group, phosphonic group or carbazole group,
R ₂ is selected from C1 to C10 alkylene group, phenyl group or thiophene group,
n is an integer from 2 to 4,
X is an anion selected from PF ₆ , Cl, Br, F, TFSI (bis(trifluoromethylsulfonyl)imide), BF ₄ and ClO ₄ . According to paragraph 1,
The compound represented by Formula 1 is an electrochromic material comprising one or more compounds selected from the compounds of Formulas 1-1 to 1-3:
[Formula 1-1]
[X] ₂
[Formula 1-2]
[X] ₂
[Formula 1-3]
[X] ₄
In Formulas 1-1 to 1-3, X is the same as Formula 1. According to paragraph 2,
An electrochromic material characterized in that the compounds of Formula 1-1, Formula 1-2, and Formula 1-3 are contained in a molar ratio of 1:1:1, respectively. According to paragraph 1,
The polyhedral oligomeric silsesquioxane (POSS) derivative containing the vinyl group is an electrochromic material represented by the following formula (2):
[Formula 2]

In Formula 2,
POSS is Polyhedral Oligomeric Silsesquioxane (POSS),
R ₃ is selected from C1 to C10 alkylene group, phenyl group, thiophene group, acetylene group, vinyl group, cyanovinyl group, phosphonic group or carbazole group,
m is an integer from 1 to 8. first and second conductive substrates; and
It includes an electrochromic layer disposed between the first and second conductive substrates,
The electrochromic layer includes the electrochromic material according to claim 1,
Electrochromic device. According to clause 5,
The electrochromic material is characterized in that it is contained in an ionic gel,
Electrochromic device. According to clause 6,
The ionic gel is characterized in that it includes a polymer matrix, an ion conductive material, and an anode material.
Electrochromic device. In clause 7,
The polymer matrix is poly(ethylene glycol-diacrylated, PEG-DA), polyurethane (PU) and its derivatives, polyvinyl alcohol (PVA), and polyvinyl butyral. , PVB), polyvinylidene fluoride (PVDF) and its derivatives, polymethyl methacrylate (PMMA),
Electrochromic device. In clause 7,
The ion conductive material is a room temperature ionic liquid containing 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (BMIM-TFSI) or 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMIM-TFSI), or lithium. Characterized in that it contains a salt (lithium salt),
Electrochromic device. In clause 7,
The anode material is characterized in that it contains ferrocene and its derivatives, or hydroquinone and its derivatives,
Electrochromic device. Polyhedral oligomeric silsesquioxane (POSS) derivative containing a vinyl group on the first conductive substrate, a compound represented by the following formula (1), a polymer matrix, an ion conductive material, an anode material, ions including a solvent and an initiator forming an electrochromic layer by applying a gel composition; and
A method of manufacturing an electrochromic device comprising: placing a second conductive substrate on the electrochromic layer and then UV curing it:
[Formula 1]
[X] _n
In Formula 1,
R ₁ is selected from C0, methylene group, phenyl group, thiophene group, acetylene group, vinyl group, cyanovinyl group, phosphonic group or carbazole group,
R ₂ is selected from C1 to C10 alkylene group, phenyl group or thiophene group,
n is an integer from 2 to 4,
X is an anion selected from PF ₆ , Cl, Br, F, TFSI (bis(trifluoromethylsulfonyl)imide), BF ₄ , and ClO ₄ . According to clause 11,
A method of manufacturing an electrochromic device, wherein the compound represented by Formula 1 includes one or more compounds selected from the compounds of Formulas 1-1 to 1-3:
[Formula 1-1]
[X] ₂
[Formula 1-2]
[X] ₂
[Formula 1-3]
[X] ₄
In Formulas 1-1 to 1-3, X is the same as Formula 1. According to clause 12,
The ionic gel composition is a method of manufacturing an electrochromic device, characterized in that it contains the compounds of Formula 1-1, Formula 1-2, and Formula 1-3, respectively, at a molar ratio of 1:1:1. According to clause 11,
A method of manufacturing an electrochromic device, wherein the polyhedral oligomeric silsesquioxane (POSS) derivative containing the vinyl group is represented by the following formula (2):
[Formula 2]

In Formula 2,
POSS is Polyhedral Oligomeric Silsesquioxane (POSS),
R ₃ is selected from C1 to C10 alkylene group, phenyl group, thiophene group, acetylene group, vinyl group, cyanovinyl group, phosphonic group or carbazole group,
m is an integer from 1 to 8. According to clause 11,
The polymer matrix is poly(ethylene glycol-diacrylated, PEG-DA), polyurethane (PU) and its derivatives, polyvinyl alcohol (PVA), and polyvinyl butyral. , PVB), polyvinylidene fluoride (PVDF) and its derivatives, and polymethyl methacrylate (PMMA),
The ion conductive material is a room temperature ionic liquid containing 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (BMIM-TFSI) or 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMIM-TFSI), or lithium. Contains lithium salt,
The anode material includes ferrocene and its derivatives, or hydroquinone and its derivatives,
The solvent includes one or more selected from acetone, ethanol, methanol, dimethylformamide, dimethyl sulfoxide, and dimethylacetamide,
The initiator is characterized in that it includes dimethoxyphenylacetophenone and derivatives, or 2-hydroxy-2-methylpropiophenone and derivatives,
Method of manufacturing electrochromic device.