Electrochromic element and driving method thereof

Abstract

To provide an electrochromic element having high memory property without color remaining.SOLUTION: An electrochromic element is provided, including: a first electrode; a second electrode apart from and opposite to the first electrode; an electrolyte layer between the first and second electrodes, containing at least one of an oxidizable substance and a reducible substance; an oxidizing electrochromic layer between the first electrode and the electrolyte layer, containing an oxidizing electrochromic compound; and a reducing electrochromic layer between the second electrode and the electrolyte layer, containing a reducing electrochromic compound, wherein an oxidation potential of the oxidizable substance is nobler than that of the oxidizing electrochromic compound, a reduction potential of the reducible substance is baser than that of the reducing electrochromic compound, an oxidation reaction of the oxidizable substance is irreversible, and the reduction reaction of the reducible substance is irreversible.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an electrochromic element and a method for driving the same.

Background Art

[0002] Electrochromism is a phenomenon in which a reversible oxidation-reduction reaction occurs by applying a voltage, and the color of a substance changes. Since the electrochromism can be used, for example, for dimming, signage, etc., extensive research and development have been carried out.

[0003] An electrochromic element that utilizes the electrochromism (hereinafter, "electrochromic" may be described as "EC") generally has an ion-conductive electrolyte layer provided between two opposing electrodes, and an oxidation-reduction reaction is caused by applying a voltage between the electrodes. When a reduction reaction occurs on the surface of one of the two opposing electrodes, an oxidation reaction, which is the reverse reaction, occurs on the surface of the other electrode.

[0004] One of the problems of the EC element is that even when driving to return to the initial state after driving to change the color from the initial state, color residue that does not completely return to the initial state occurs. When the EC element is used for dimming applications, the reliability as an EC element is lost due to the color residue. For this reason, various proposals have been made for the EC element without color residue. For example, in a complementary EC element in which an EC compound is dissolved in an electrolyte, an EC element having an oxidizable substance that is more easily oxidized than the oxidizing EC compound or a reducible substance that is more easily reduced than the reducing EC compound has been proposed (see, for example, Patent Document 1). Also, an EC element containing in the electrolyte an oxidized substance that is less likely to be oxidized than the reversible oxidation reaction of the oxidizing EC compound and is more likely to be oxidized than the irreversible oxidation reaction of the oxidizing EC compound, and a reduced substance that is less likely to be reduced than the reversible reduction reaction of the reducing EC compound and is more likely to be reduced than the irreversible reduction reaction of the reducing EC compound has been proposed (see, for example, Patent Document 2). However, the above proposal was insufficient as an EC element without color residue. Summary of the Invention Problems to be Solved by the Invention

[0005] An object of the present invention is to provide an electrochromic element having high memory properties and no color residue. The absence of color residue means that the colors in the colored state and the bleached state can be maintained even when driving is repeated. Means for Solving the Problems

[0006] The electrochromic element of the present invention as means for solving the above problems is a first electrode, a second electrode provided opposite to the first electrode with a space therebetween, an electrolyte layer containing at least one of an oxidizable substance and a reducible substance between the first electrode and the second electrode, an oxidizing electrochromic layer containing an oxidizing electrochromic compound between the first electrode and the electrolyte layer, a reducing electrochromic layer containing a reducing electrochromic compound between the second electrode and the electrolyte layer, and the oxidation potential of the oxidizable substance is nobler than the oxidation potential of the oxidizing electrochromic compound, the reduction potential of the reducible substance is lower than the reduction potential of the reducing electrochromic compound, the oxidation reaction of the oxidizable substance is irreversible, the reduction reaction of the reducible substance is irreversible. Advantages of the Invention

[0007] According to the present invention, it is possible to provide an electrochromic element having high memory properties and no color residue. Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Mode for Carrying Out the Invention

[0009] (Electrochromic device) The electrochromic device of the present invention has a first electrode, a second electrode, an electrolyte layer, and an electrochromic layer, and further has other members as required.

[0010] A first aspect of the electrochromic device of the present invention includes a first electrode, a second electrode provided opposite to the first electrode with a space therebetween, an electrolyte layer containing at least one of an oxidizable substance and a reducible substance between the first electrode and the second electrode, an oxidizing electrochromic layer containing an oxidizing electrochromic compound between the first electrode and the electrolyte layer, and a reducing electrochromic layer containing a reducing electrochromic compound between the second electrode and the electrolyte layer. The oxidation potential of the oxidizable substance is nobler than the oxidation potential of the oxidizing electrochromic compound, the reduction potential of the reducible substance is lower than the reduction potential of the reducing electrochromic compound, the oxidation reaction of the oxidizable substance is irreversible, the reduction reaction of the reducible substance is irreversible, and further has other means as required. The electrochromic device of the first aspect is also referred to as a complementary electrochromic device.

[0011] A second aspect of the electrochromic device of the present invention includes a first electrode, a second electrode provided opposite to the first electrode with a space therebetween, an electrolyte layer containing an oxidizable substance between the first electrode and the second electrode, and an electrochromic layer containing an electrochromic compound between the first electrode and the electrolyte layer. The oxidation potential of the oxidizable substance is more noble than the oxidation potential of the electrochromic compound, and the oxidation reaction of the oxidizable substance is irreversible. Further, other means are provided as necessary. The electrochromic device of the second aspect is also referred to as an oxidation-type electrochromic device.

[0012] A third aspect of the electrochromic device of the present invention includes a first electrode, a second electrode provided opposite to the first electrode with a space therebetween, an electrolyte layer containing a reducible substance between the first electrode and the second electrode, and a electrochromic layer containing a electrochromic compound between the second electrode and the electrolyte layer. The reduction potential of the reducible substance is more negative than the reduction potential of the electrochromic compound, and the reduction reaction of the reducible substance is irreversible. Further, other means are provided as necessary. The electrochromic device of the third aspect is also referred to as a reduction-type electrochromic device.

[0013] EC devices without color residue have been studied before. For example, Japanese Patent No. 5778590 describes an EC device having an oxidizable substance that is more easily oxidized than an electrochromic compound or a reducible substance that is more easily reduced than a reducible electrochromic compound in a complementary EC device in which an electrochromic compound is dissolved in an electrolyte. Although this EC device can eliminate color residue, there are problems such as poor coloration / bleaching responsiveness and memory properties due to the electrochromic compound not being supported on the electrode surface, and high power consumption. Japanese Patent Application Laid-Open No. 2018-022131 proposes an EC element containing, in an electrolyte, an oxidizable substance that is less likely to be oxidized than the reversible oxidation reaction of an oxidizing EC compound and is more likely to be oxidized than the irreversible oxidation reaction of the oxidizing EC compound, and a reducible substance that is less likely to be reduced than the reversible reduction reaction of a reducing EC compound and is more likely to be reduced than the irreversible reduction reaction of the reducing EC compound. When detecting color residue, this EC element causes the oxidized and reduced substance to undergo an oxidation-reduction reaction by applying a voltage greater than the coloring voltage, and then applies a bleaching voltage to eliminate the color residue. However, this method requires detecting color residue, and to eliminate color residue, it must pass through a dark coloring state from the state where color residue has occurred. Also, whether the color residue has been eliminated must be detected again, which not only impairs the appearance but also requires complex control. In addition, only an EC element in which an EC compound is dissolved in an electrolyte solution is shown in the examples, and an EC element in which an EC compound is supported on the electrode surface is not shown.

[0014] Therefore, as a result of intensive studies by the present inventors, by adding a substance containing an oxidizable substance or a reducible substance to the electrolyte layer and applying a voltage to return to the initial state, an oxidation-reduction reaction that is paired with the oxidation-reduction reaction when the EC compound in the color change state returns to the initial state is caused by the oxidizable substance or the reducible substance, and it has been found that the EC element can be returned to the initial state. As a result, in an EC element in which an EC compound is supported as a layer on an electrode, when it does not return to the initial state after driving to return to the initial state, an EC element that can be returned to the initial state without detecting that it has not returned to the initial state has been found, leading to the completion of the present invention.

[0015] Here, the electrochromic element of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram showing an example of an electrochromic element 201 in a first aspect. The electrochromic element 201 has a first electrode 1 and a second electrode 2 facing the first electrode 1. Further, the electrochromic element 201 has an oxidative electrochromic layer 6, an electrolyte layer 5, and a reductive electrochromic layer 9 between the first electrode 1 and the second electrode 2, and the electrolyte layer 5 contains at least one of an oxidizable substance and a reducible substance. The oxidizable substance and the reducible substance may be a single substance using chemical bonds or the like. The electrochromic element 201 may have other members as necessary. Regarding the driving method of the electrochromic element of the first aspect, in the step P1 of applying a voltage larger than the threshold voltage Vc necessary for the electrochromic element to change color from the initial state to the first electrode 1 and the second electrode 2 of the electrochromic element 201, the oxidative electrochromic compound contained in the oxidative electrochromic layer 6 undergoes an oxidation reaction, the oxidative electrochromic layer 6 changes color, the reductive electrochromic compound contained in the reductive electrochromic layer 9 undergoes a reduction reaction, the reductive electrochromic layer 9 changes color, and a color change state of the electrochromic element 201 is obtained. Further, in the step P2 of applying a voltage for returning from the color change state to the initial state, the oxidized form of the oxidative electrochromic compound undergoes a reduction reaction and returns to the original oxidative electrochromic compound, the reduced form of the reductive electrochromic compound undergoes an oxidation reaction and returns to the original reductive electrochromic compound, and the electrochromic element 201 can be returned to the initial state.

[0016] FIG. 2 is a schematic diagram showing an example of the electrochromic element 202 of the second aspect. The electrochromic element 202 has a first electrode 1 and a second electrode 2 facing the first electrode 1. Further, the electrochromic element 202 has an oxidative electrochromic layer 6 and an electrolyte layer 5 between the first electrode 1 and the second electrode 2, and the electrolyte layer 5 contains an oxidizable substance. The electrochromic element 202 may have other members as necessary. Regarding the driving method of the electrochromic element according to the second aspect, in step P1 of applying a voltage greater than the threshold voltage Vc required for the electrochromic element to change color from the initial state to the first electrode 1 and the second electrode 2 of the electrochromic element 202, the electrochromic compound contained in the electrochromic layer 6 undergoes an oxidation reaction, causing the electrochromic layer 6 to change color, and the color change state of the electrochromic element 201 is obtained. Further, in step P2 of applying a voltage to return from the color change state to the initial state, the oxidized form of the electrochromic compound undergoes a reduction reaction, returning to the original electrochromic compound, and the electrochromic element 202 can be returned to the initial state.

[0017] FIG. 3 is a schematic diagram showing an example of the electrochromic element 203 according to the third aspect. The electrochromic element 203 has a first electrode 1 and a second electrode 2 facing the first electrode 1. Further, the electrochromic element 203 has a reducing electrochromic layer 9 and an electrolyte layer 5 between the first electrode 1 and the second electrode 2, and the electrolyte layer 5 contains a substance to be reduced. The electrochromic element 203 may have other members as required. Regarding the driving method of the electrochromic element according to the third aspect, in step P1 of applying a voltage greater than the threshold voltage Vc required for the electrochromic element to change color from the initial state to the first electrode 1 and the second electrode 2 of the electrochromic element 203, the reducing electrochromic compound contained in the reducing electrochromic layer 9 undergoes a reduction reaction, causing the reducing electrochromic layer 9 to change color, and the color change state of the electrochromic element 203 is obtained. Further, in step P2 of applying a voltage to return from the color change state to the initial state, the reduced form of the reducing electrochromic compound undergoes an oxidation reaction, returning to the original reducing electrochromic compound, and the electrochromic element 203 can be returned to the initial state.

[0018] <The first electrode, the second electrode> As the materials for the first electrode and the second electrode, there is no particular limitation as long as they are commonly used conductors, and they can be appropriately selected according to the purpose. However, a transparent electrode having transparency is preferred. There is no particular limitation on the transparent electrode, and it can be appropriately selected according to the purpose. For example, indium tin oxide doped with tin (hereinafter referred to as "ITO"), tin oxide doped with fluorine, tin oxide doped with antimony, and inorganic materials such as zinc oxide can be mentioned. Among these, InSnO, GaZnO, SnO, In 2 O 3 , ZnO are preferred. Furthermore, a carbon nanotube having transparency or other highly conductive non-transparent materials such as Au, Ag, Pt, and Cu can be formed in a fine network shape, and an electrode with improved conductivity while maintaining transparency may be used. The thickness of each of the first electrode and the second electrode is adjusted so that an electric resistance value required for the oxidation-reduction reaction of the electrochromic layer can be obtained. When ITO is used as the material for the first electrode and the second electrode, the thickness of each of the first electrode and the second electrode is preferably, for example, 50 nm or more and 500 nm or less.

[0019] There is no particular limitation on the manufacturing method of each of the first electrode and the second electrode, and it can be appropriately selected according to the purpose. For example, a vacuum evaporation method, a sputtering method, an ion plating method, etc. can be used. As long as the materials of each of the first electrode and the second electrode can be formed by coating, there is no particular limitation. For example, spin coating method, casting method, microgravure coating method, gravure coating method, bar coating method, roll coating method, wire bar coating method, dip coating method, slit coating method, capillary coating method, spray coating method, nozzle coating method, gravure printing method, screen printing method, flexographic printing method, offset printing method, reverse printing method, inkjet printing method and other various printing methods can be used.

[0020] <Electrolyte layer> The electrolyte layer is filled between the first electrode and the second electrode. The electrolyte layer of the electrochromic device of the present invention contains at least one of an oxidizable substance and a reducible substance, and further contains other components as necessary. The electrolyte layer of the electrochromic device according to the second aspect of the present invention contains an oxidizable substance, and further contains other components as necessary. The electrolyte layer of the electrochromic device according to the third aspect of the present invention contains a reducible substance, and further contains other components as necessary.

[0021] -Oxidizable substance- The oxidizable substance is a substance that exhibits an electrochemical oxidation reaction. The oxidation potential of the oxidizable substance is preferably nobler than the oxidation potential of the oxidizing electrochromic compound described later. This is because in normal coloration / bleaching driving in a state without color residue, it is preferable that the oxidizable substance does not undergo an oxidation-reduction reaction. Since the oxidation potential of the oxidizable substance is nobler than the oxidation potential of the oxidizing electrochromic compound, even when a potential at which the oxidizing electrochromic compound undergoes an oxidation reaction is applied to the electrode, the amount of oxidation reaction of the oxidizable substance can be kept low. When the oxidation potential of the oxidizable substance is lower than the oxidation potential of the oxidizing electrochromic compound, not only does the oxidizable substance undergo an oxidation reaction during normal coloration / bleaching driving and the efficiency deteriorates, but also the oxidizable substance gives electrons to the oxidized form of the oxidizing electrochromic compound, so that the electrochromic device cannot maintain its color change state and the memory property deteriorates. When the oxidation potential of the oxidizable substance is nobler than the oxidation potential of the oxidizing electrochromic compound, the electrochromic device in the color change state can maintain its color change state and can be returned to the initial state at any timing by applying a voltage. As the oxidizable substance satisfying this condition, although it depends on the oxidation potential of the electrochromic compound, for example, since the oxidation potential of a triarylamine derivative is approximately 0.2 to 0.6 V (vs. ferrocene), any functional group that undergoes an oxidation reaction at a potential more noble than this can be used. Specifically, pyridines, polycyclic aromatics, heterocyclic compounds, alkoxybenzenes, cyanobenzenes, phosphate esters, phosphites, annulenes, etc. can be used.

[0022] It is preferable that the oxidation reaction of the oxidizable substance is irreversible. Here, "irreversible" means that it is not easy for the oxidized form of the oxidizable substance after the oxidation reaction to be reduced back to the original oxidizable substance. Here, not being easy to return means that the ratio of returning to the original oxidizable substance is small. As the ratio of returning to the original oxidizable substance, 1 / 2 or less is preferable, 1 / 10 or less is more preferable, and 1 / 100 or less is even more preferable. When the oxidation reaction of the oxidizable substance is reversible, since the oxidized form of the oxidizable substance undergoes a reduction reaction when returning to the original oxidizable substance, in the complementary electrochromic device as in the first embodiment, the reduction reaction of the electrochromic compound does not occur by the amount of the reduction reaction, and there arises a problem that the color of the electrochromic device becomes different from the original. Also, when the oxidizable substance oxidized on the surface of the second electrode reaches the first electrode through the electrolyte layer, the oxidized form of the oxidizable substance and the electrochromic compound having oxidizing properties exchange electrons, and the electrochromic compound having oxidizing properties changes to a color-changing state. When the oxidation reaction of the oxidizable substance is irreversible, the above-mentioned problems do not occur, so the color of the electrochromic device remains the same as the original when the color changes.

[0023] Examples of the oxidizable substance showing the irreversible oxidation reaction include substances containing phenols, alkoxybenzenes, cyanobenzenes, phosphate esters, phosphites, annulenes, etc.

[0024] --Phenols-- Examples of the phenols include compounds represented by the following general formula X1. [Chemical formula] (General formula X1) Here, R31 to R35 in the general formula X1 are each independently a hydrogen atom, a halogen atom, a hydroxyl group, a nitro group, a cyano group, an amide group, a carbonyl group, an alkyl group which may have a substituent, an aryl group which may have a substituent, an alkoxy group which may have a substituent, an aryloxy group which may have a substituent, an alkylthio group which may have a substituent, an arylthio group which may have a substituent, a heterocyclic group which may have a substituent, etc. Among these, from the viewpoint of stable operation, an alkyl group, an alkoxy group, a hydrogen atom, an aryl group, an aryloxy group, and a halogen atom are preferable.

[0025] Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, a tertiary butyl group, etc. Examples of the aryl group include a phenyl group, a naphthyl group, etc. Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, etc. Examples of the aryloxy group include a phenoxy group, a 1-naphthyloxy group, a 2-naphthyloxy group, a 4-methoxyphenoxy group, a 4-methylphenoxy group, etc. Examples of the heterocyclic group include carbazole, dibenzofuran, dibenzothiophene, oxadiazole, thiadiazole, etc. Examples of the substituent that is further substituted by the substituent include a halogen atom, a nitro group, a cyano group, an alkyl group such as a methyl group and an ethyl group, an alkoxy group such as a methoxy group and an ethoxy group, an aryloxy group such as a phenoxy group, an aryl group such as a phenyl group and a naphthyl group, a benzyl group, etc.

[0026] Specific examples of the compound (phenols) represented by the general formula X1 include compounds having structures as shown below. The phenols are not limited to these.

[0027] [Exemplary Compound X1-1] [Chemical Formula]

[0028] [Exemplary Compound X1-2] [Chemical Formula]

[0029] [Exemplary Compound X1-3] [Chemical Formula]

[0030] [Exemplary Compound X1-4] [Chemical Formula]

[0031] [Exemplary Compound X1-5] [Chemical Formula]

[0032] [Exemplary Compound X1-6] [Chemical Formula]

[0033] [Exemplary Compound X1-7] [Chemical Formula]

[0034] [Exemplary Compound X1-8] [Chemical formula]

[0035] [Exemplary compound X1-9] [Chemical formula]

[0036] [Exemplary compound X1-10] [Chemical formula]

[0037] [Exemplary compound X1-11] [Chemical formula]

[0038] [Exemplary compound X1-12] [Chemical formula]

[0039] [Exemplary compound X1-13] [Chemical formula]

[0040] [Exemplary compound X1-14] [Chemical formula]

[0041] --Alkoxybenzenes-- Examples of the alkoxybenzenes include compounds represented by the following general formula X2, etc.

[0042] [Chemical formula] (General formula X2) Here, as R36 to R41 in the above general formula X2, each independently represents a hydrogen atom, a halogen atom, a nitro group, a cyano group, an amide group, a carbonyl group, an alkyl group which may have a substituent, an aryl group which may have a substituent, an alkoxy group which may have a substituent, an aryloxy group which may have a substituent, an alkylthio group which may have a substituent, an arylthio group which may have a substituent, a heterocyclic group which may have a substituent, and the like. However, at least one or more of R36 to R41 is an alkoxy group. Since the alkoxy group has an electron-donating property, the number of the alkoxy groups in the above general formula X2 is preferably 1 to 3. When the number of the alkoxy groups in the above general formula X2 is 1 to 3, problems such as the oxidation potential becoming too low can be solved. Among these, from the viewpoint of stable operation, an alkyl group, an alkoxy group, a hydrogen atom, an aryl group, an aryloxy group, and a halogen atom are preferable.

[0043] Specific examples of the compound (alkoxybenzenes) represented by the above general formula X2 include compounds having structures shown below. Note that the alkoxybenzenes are not limited to these.

[0044] [Exemplary Compound X2-1] [Chemical formula]

[0045] [Exemplary Compound X2-2] [Chemical formula]

[0046] [Exemplary Compound X2-3] [Chemical formula]

[0047] [Exemplary Compound X2-4] [Chem.]

[0048] [Exemplary Compound X2-5] [Chem.]

[0049] [Exemplary Compound X2-6] [Chem.]

[0050] [Exemplary Compound X2-7] [Chem.]

[0051] [Exemplary Compound X2-8] [Chem.]

[0052] [Exemplary Compound X2-9] [Chem.]

[0053] [Exemplary Compound X2-10] [Chem.]

[0054] [Exemplary Compound X2-11] [Chem.]

[0055] [Exemplary Compound X2-12] [Chem.]

[0056] [Exemplary Compound X2-13] [Chem.]

[0057] [Exemplary Compound X2-14] [Chem.]

[0058] --Cyano-benzenes-- Examples of the cyano-benzenes include compounds represented by the following general formula X3, etc.

[0059] [Chem.] (General formula X3) Here, R42 to R46 in the general formula X3 each independently represent a hydrogen atom, a halogen atom, a nitro group, a cyano group, an amide group, a carbonyl group, an alkyl group which may have a substituent, an aryl group which may have a substituent, an aryloxy group which may have a substituent, an alkylthio group which may have a substituent, an arylthio group which may have a substituent, a heterocyclic group which may have a substituent, etc.

[0060] Specific examples of the compound (cyano-benzenes) represented by the general formula X3 include compounds having structures as shown below. Note that the cyano-benzenes are not limited to these.

[0061] [Exemplary Compound X3-1] [Chem.]

[0062] [Exemplary Compound X3-2] [Chemical]

[0063] [Exemplary Compound X3-3] [Chemical]

[0064] [Exemplary Compound X3-4] [Chemical]

[0065] [Exemplary Compound X3-5] [Chemical]

[0066] [Exemplary Compound X3-6] [Chemical]

[0067] [Exemplary Compound X3-7] [Chemical]

[0068] [Exemplary Compound X3-8] [Chemical]

[0069] [Exemplary Compound X3-9] [Chemical]

[0070] [Exemplary Compound X3-10] [Chemical]

[0071] --Phosphate salts-- Examples of the phosphate salts include compounds represented by the following general formula X4.

[0072] [Chemical formula] (General formula X4) Here, R47 and R48 in the general formula X4 each independently include an alkyl group which may have a substituent, an aryl group which may have a substituent, an aryloxy group which may have a substituent, a heterocyclic group which may have a substituent, and the like. X in the general formula X4 is a cation that forms a pair with the anion part, and is not particularly limited as long as it does not inhibit the electrochemical reaction of the electrochromic compound, the electrochemical reactions of the substance to be oxidized and the substance to be reduced. Examples of X in the general formula X4 include alkali metal ions such as lithium, potassium, and sodium; imidazole derivatives such as N,N-dimethylimidazole, N,N-methylethylimidazole, and N,N-methylpropylimidazole; pyridinium derivatives such as N,N-dimethylpyridinium and N,N-methylpropylpyridinium; aliphatic quaternary ammonium systems such as trimethylpropylammonium, triethylhexylammonium, and tetraethylammonium. Further, X may be chemically bonded via R47 or R48 and may be a zwitterion.

[0073] Specific examples of the compound (phosphate salts) represented by the general formula X4 include compounds having structures shown below. Note that the phosphate salts are not limited to these.

[0074] [Exemplary compound X4-1] [Chemical formula]

[0075] [Exemplary Compound X4-2] [Chem.]

[0076] [Exemplary Compound X4-3] [Chem.]

[0077] [Exemplary Compound X4-4] [Chem.]

[0078] [Exemplary Compound X4-5] [Chem.]

[0079] --Phosphite Esters-- Examples of the phosphite esters include compounds represented by the following general formula X5.

[0080] [Chem.] (General formula X5) Here, R49 to R51 in the general formula X5 each independently represent a hydrogen atom, a halogen atom, a nitro group, a cyano group, an amide group, a carbonyl group, an alkyl group which may have a substituent, an aryl group which may have a substituent, an alkoxy group which may have a substituent, an aryloxy group which may have a substituent, an alkylthio group which may have a substituent, an arylthio group which may have a substituent, a heterocyclic group which may have a substituent, and the like.

[0081] Specific examples of the compound (phosphite esters) represented by the general formula X5 include compounds having structures shown below. Incidentally, the phosphites are not limited to these.

[0082] [Exemplary Compound X5-1] [Chemical Formula]

[0083] [Exemplary Compound X5-2] [Chemical Formula]

[0084] [Exemplary Compound X5-3] [Chemical Formula]

[0085] [Exemplary Compound X5-4] [Chemical Formula]

[0086] [Exemplary Compound X5-5] [Chemical Formula]

[0087] [Exemplary Compound X5-6] [Chemical Formula]

[0088] [Exemplary Compound X5-7] [Chemical Formula]

[0089] [Exemplary Compound X5-8] [Chemical Formula]

[0090] --Anulenes-- Examples of the anulenes include compounds represented by the following general formula X6.

[0091] [Chemical formula] (General formula X6) Here, R52 to R59 in the general formula X6 are each independently a hydrogen atom, a halogen atom, a nitro group, a cyano group, an amide group, a carbonyl group, an alkyl group which may have a substituent, an aryl group which may have a substituent, an alkoxy group which may have a substituent, an aryloxy group which may have a substituent, an alkylthio group which may have a substituent, an arylthio group which may have a substituent, a heterocyclic group which may have a substituent, and the like.

[0092] Specific examples of the compound (anulenes) represented by the general formula X6 include compounds having structures as shown below. Note that the anulenes are not limited to these.

[0093] [Exemplary compound X6-1] [Chemical formula]

[0094] [Exemplary compound X6-2] [Chemical formula]

[0095] [Exemplary compound X6-3] [Chemical formula]

[0096] [Exemplary compound X6-4] [Chemical formula]

[0097] [Exemplary Compound X6-5] [Chem.]

[0098] [Exemplary Compound X6-6] [Chem.]

[0099] [Exemplary Compound X6-7] [Chem.]

[0100] The oxidizable substance is preferably colorless and transparent. When the oxidizable substance is not colorless and transparent, even when the electrochromic element is in a non-color-changing state, the color of the oxidizable substance may develop, so that the color state originally desired to be realized by the electrochromic element may not be reproduced.

[0101] -Reducible Substance- The reducible substance is a substance that exhibits an electrochemical reduction reaction. The reducible substance has a reducible group, which is a functional group that exhibits an electrochemical reduction reaction in the reducible substance.

[0102] The reduction potential of the reducible substance is preferably lower than the reduction potential of the reducing electrochromic compound. In normal coloration / bleaching driving in a state without color residue, it is preferable that the reducible substance does not undergo an oxidation-reduction reaction. Since the reduction potential of the reducible substance is lower than the reduction potential of the reducing electrochromic compound, even when a potential at which the reducing electrochromic compound undergoes a reduction reaction is applied to the electrode, the amount of the reduction reaction of the reducible substance can be kept low. When the reduction potential of the reducible substance is nobler than the reduction potential of the reductive electrochromic compound, not only does the reducible substance undergo a reduction reaction during normal color development and fading driving, resulting in poor efficiency, but also the reducible group takes electrons from the reduced form of the reductive electrochromic compound, so that the electrochromic element cannot maintain its color change state and its memory property deteriorates. When the reduction potential of the reducible group is lower than the reduction potential of the reductive electrochromic compound, the electrochromic element in the color change state can maintain its color change state and can be returned to the initial state at any timing by applying a voltage. Examples of the reducible substance that satisfies such conditions include, although it depends on the reduction potential of the reductive electrochromic compound, for example, since the reduction potential of the viologen system is approximately -1.2 to -0.8 V (vs. ferrocene), any functional group that undergoes a reduction reaction at a potential lower than this potential can be used. Specifically, acid anhydrides, aromatic ketones, unsaturated fatty acid esters, etc. can be used.

[0103] The reduction reaction of the reducible group is preferably irreversible. Here, being irreversible means that it is not easy for the reduced form of the reducible group after the reduction reaction to be oxidized and return to the original reducible group. When the reduction reaction of the reducible group is reversible, since the reduced form of the reducible group undergoes an oxidation reaction when returning to the original reducible group, in the complementary electrochromic element which is the first aspect of the present invention, the oxidation reaction of the oxidative electrochromic compound does not occur by the amount of the oxidation reaction, and a problem occurs that the color tone of the electrochromic element is different from the original. When the reduction reaction of the reducible group is irreversible, the above-mentioned problem does not occur, so the color tone at the time of color change of the electrochromic element remains the same as the original. Examples of the reducible substance showing the irreversible reduction reaction include substances containing acid anhydrides, aromatic ketones, unsaturated fatty acid esters, etc.

[0104] --Acid anhydrides-- Examples of the acid anhydrides include compounds represented by the following general formula X7 and the like.

[0105] [Chemical Formula] (General formula X7) Here, R60 and R61 in the general formula X7 are each independently a hydrogen atom, a halogen atom, a nitro group, a cyano group, an amide group, a carbonyl group, an alkyl group which may have a substituent, an aryl group which may have a substituent, an alkoxy group which may have a substituent, an aryloxy group which may have a substituent, an alkylthio group which may have a substituent, an arylthio group which may have a substituent, a heterocyclic group which may have a substituent, and the like. R60 and R61 in the general formula X7 may be connected via an organic group.

[0106] Specific examples of the compound (acid anhydrides) represented by the general formula X7 include compounds having structures shown below and the like. Note that the acid anhydrides are not limited to these.

[0107] [Exemplary compound X7-1] [Chemical Formula]

[0108] [Exemplary compound X7-2] [Chemical Formula]

[0109] [Exemplary compound X7-3] [Chemical Formula]

[0110] [Exemplary compound X7-4] [Chemical Formula]

[0111] [Exemplary Compound X7-5] [Chem.]

[0112] [Exemplary Compound X7-6] [Chem.]

[0113] [Exemplary Compound X7-7] [Chem.]

[0114] [Exemplary Compound X7-8] [Chem.]

[0115] [Exemplary Compound X7-9] [Chem.]

[0116] [Exemplary Compound X7-10] [Chem.]

[0117] [Exemplary Compound X7-11] [Chem.]

[0118] [Exemplary Compound X7-12] [Chem.]

[0119] --Aromatic ketones-- Examples of the aromatic ketones include compounds represented by the following general formula X8, etc.

[0120] [Chemical formula] Here, as R62 to R67 in general formula X7, each independently represents a hydrogen atom, a halogen atom, a nitro group, an amide group, a carbonyl group, an ester group, an alkyl group which may have a substituent, an aryl group which may have a substituent, an alkoxy group which may have a substituent, an aryloxy group which may have a substituent, an alkylthio group which may have a substituent, an arylthio group which may have a substituent, a heterocyclic group which may have a substituent, etc.

[0121] Specific examples of the compound (aromatic ketones) represented by the general formula X8 include compounds having structures as shown below. Note that the aromatic ketones are not limited to these.

[0122] [Exemplary compound X8-1] [Chemical formula]

[0123] [Exemplary compound X8-2] [Chemical formula]

[0124] [Exemplary compound X8-3] [Chemical formula]

[0125] [Exemplary compound X8-4] [Chemical formula]

[0126] [Exemplary Compound X8-5] [Chem.]

[0127] [Exemplary Compound X8-6] [Chem.]

[0128] [Exemplary Compound X8-7] [Chem.]

[0129] [Exemplary Compound X8-8] [Chem.]

[0130] [Exemplary Compound X8-9] [Chem.]

[0131] --Unsaturated Fatty Acid Esters-- Examples of the unsaturated fatty acid esters include compounds represented by the following general formula X9, etc.

[0132] [Chem.] Here, R68 and R69 each independently represent a hydrogen atom, a halogen atom, a nitro group, a cyano group, an amide group, a carbonyl group, an alkyl group which may have a substituent, an alkenyl group which may have a substituent, an alkoxy group which may have a substituent, an alkylthio group which may have a substituent, a heterocyclic group which may have a substituent, etc.

[0133] Specific examples of the compound (unsaturated fatty acid esters) represented by the general formula X9 include compounds having structures as shown below. Note that the unsaturated fatty acid esters are not limited to these.

[0134] [Exemplary Compound X9-1] [Chemical Formula]

[0135] [Exemplary Compound X9-2] [Chemical Formula]

[0136] [Exemplary Compound X9-3] [Chemical Formula]

[0137] [Exemplary Compound X9-4] [Chemical Formula]

[0138] [Exemplary Compound X9-5] [Chemical Formula]

[0139] [Exemplary Compound X9-6] [Chemical Formula]

[0140] [Exemplary Compound X9-7] [Chemical Formula]

[0141] The reducible substance is preferably colorless and transparent. When the reducible substance is not colorless and transparent, even when the electrochromic element is in a non-color-changing state, the color of the reducible substance may develop, and thus the color state that the electrochromic element originally intends to achieve may not be reproducible. In addition, the oxidizable substance and the reducible substance may be the same substance via a chemical bond.

[0142] -Other components- There are no particular restrictions on the other components as long as they are those used in ordinary electrochromic elements, and they can be appropriately selected according to the purpose. Examples include electrolytes.

[0143] There are no particular restrictions on the electrolyte, and it can be appropriately selected according to the purpose. For example, inorganic ion salts such as alkali metal salts and alkaline earth metal salts, quaternary ammonium salts, acids, and supporting salts of alkalis can be used. Specifically, LiClO 4 , LiBF 4 , LiAsF 6 , LiPF 6 , LiCF 3 SO 3 , LiCF 3 COO, KCl, NaClO 3 , NaCl, NaBF 4 , NaSCN, KBF 4 , Mg(ClO 4 ) 2 , Mg(BF 4 ) 2 etc. can be mentioned. As the electrolyte, an ionic liquid obtained by arbitrarily combining a cation component and an anion component may be used. Since the ionic liquid has a molecular structure that exhibits a liquid state in a wide temperature range including room temperature, it is preferable.

[0144] The cation component is not particularly limited and can be appropriately selected according to the purpose. For example, imidazole derivatives such as N,N-dimethylimidazole salts, N,N-methylethylimidazole salts, and N,N-methylpropylimidazole salts; pyridinium derivatives such as N,N-dimethylpyridinium salts and N,N-methylpropylpyridinium salts; aliphatic quaternary ammonium systems such as trimethylpropylammonium salts, trimethylhexylammonium salts, and triethylhexylammonium salts, etc. can be mentioned.

[0145] The anion component is not particularly limited and can be appropriately selected according to the purpose. However, considering the stability in the atmosphere, it is preferable to use a fluorine-containing compound. Specific examples include BF 4 - , CF 3 SO 3 - , PF 4 - , (CF 3 SO 2 ) 2 N - , etc. can be mentioned.

[0146] The electrolyte may be directly dissolved in any of the photopolymerizable monomer, oligomer, and liquid crystal material. In the case of poor solubility, a solution obtained by dissolving the electrolyte in a small amount of solvent may be mixed with any of the photopolymerizable monomer, oligomer, and liquid crystal material and used.

[0147] The solvent is not particularly limited and can be appropriately selected according to the purpose. For example, propylene carbonate, acetonitrile, γ-butyrolactone, ethylene carbonate, sulfolane, dioxolane, tetrahydrofuran, 2-methyltetrahydrofuran, dimethyl sulfoxide, 1,2-dimethoxyethane, 1,2-ethoxymethoxyethane, polyethylene glycol, alcohols, or a mixed solvent thereof, etc. can be mentioned.

[0148] The electrolyte layer containing the electrolyte does not necessarily have to be a low-viscosity liquid and can take various forms such as gel-like, polymer crosslinked type, liquid crystal dispersed type, etc. By forming the electrolyte layer into a gel-like or solid state, advantages such as improved element strength and reliability can be obtained. As a solidification method, it is preferable to hold the electrolyte in a polymer resin. This is because high ionic conductivity and solid strength can be obtained. Furthermore, as the polymer resin, a resin that can be photocured is preferable. This is because the element can be manufactured at a low temperature and in a short time compared to methods of thinning the film by thermal polymerization or evaporating the solvent.

[0149] There is no particular limitation on the average thickness of the electrolyte layer, and it can be appropriately selected according to the purpose, but it is preferably 100 nm or more and 100 μm or less.

[0150] <Electrochromic layer> In the first aspect, it has an oxidative electrochromic layer and a reductive electrochromic layer. In the second aspect, it has an oxidative electrochromic layer. In the third aspect, it has a reductive electrochromic layer.

[0151] -Oxidative electrochromic layer- The oxidative electrochromic layer is between the first electrode and the electrolyte layer and may be laminated on the first electrode. Only one layer of the oxidative electrochromic layer may be laminated, or two or more layers may be laminated.

[0152] The oxidative electrochromic layer contains an oxidative electrochromic compound. The oxidative electrochromic compound is a compound whose light absorption in the light wavelength region targeted by the electrochromic device changes by an electrochemical oxidation reaction from the initial state. The oxidizing electrochromic compound is not particularly limited as long as it can be held as a layer on the electrode, and can be appropriately selected according to the purpose, and may be an inorganic compound or an organic compound.

[0153] The inorganic compound is not particularly limited and can be appropriately selected according to the purpose. Examples thereof include iridium oxide, nickel oxide, rhodium oxide, chromium oxide, and the like. These may be used alone or in combination of two or more. The organic compound is not particularly limited and can be appropriately selected according to the purpose. Examples thereof include amines having an aromatic ring (for example, phenazine derivatives, triarylamine derivatives), thiophene derivatives, pyrrole derivatives, thiazine derivatives, allylaryl methane derivatives, bisphenyl methane derivatives, xanthene derivatives, fluoran derivatives, and spiropyran derivatives. Among these, triarylamine derivatives are preferable from the viewpoints of high driving durability, light durability, color selectivity, and contrast. These may be used alone or in combination of two or more.

[0154] Examples of the triarylamine derivative include compounds represented by the following general formula 1. A n -B m [General formula 1] However, in the general formula 1, when n = 2, m is 0, and when n = 1, m is 0 or 1. A in the general formula 1 has a structure represented by the following general formula 2, and is bonded to B at any position from R 1 to R 15 . B in the general formula 1 has a structure represented by the following general formula 3, and is bonded to A at any position from R 16 to R 21 .

Chemical formula

Chemical formula

[0155] The polymerizable functional group is not particularly limited as long as it has a carbon-carbon double bond and is polymerizable, and can be appropriately selected according to the purpose. For example, a vinyl group, a styryl group, a 2-methyl-1,3-butadienyl group, a vinylcarbonyl group, an acryloyloxy group, an acryloylamide group, a vinylthioether group, etc. can be mentioned.

[0156] The functional group capable of being directly or indirectly bonded to the hydroxyl group is not particularly limited as long as it can be directly or indirectly bonded to the hydroxyl group by hydrogen bonding, adsorption or chemical reaction, and can be appropriately selected according to the purpose. Specific examples of its structure include silyl groups (or silanol groups) such as phosphonic acid groups, phosphoric acid groups, trichlorosilyl groups, trialkoxysilyl groups, monochlorosilyl groups, monoalkoxysilyl groups, and carboxyl groups. Examples of the trialkoxysilyl group include a triethoxysilyl group and a trimethoxysilyl group. Among these, a phosphonic acid group and a silyl group (trialkoxysilyl group or trihydroxysilyl group) having a high binding force to a conductive or semiconductive nanostructure are preferable.

[0157] The monovalent organic group is not particularly limited and can be appropriately selected according to the purpose. For example, each independently, a hydrogen atom, a halogen atom, a hydroxyl group, a nitro group, a cyano group, a carboxyl group, an alkoxycarbonyl group which may have a substituent, an aryloxycarbonyl group which may have a substituent, an alkylcarbonyl group which may have a substituent, an arylcarbonyl group which may have a substituent, an amide group, a monoalkylaminocarbonyl group which may have a substituent, a dialkylaminocarbonyl group which may have a substituent, a monoarylaminocarbonyl group which may have a substituent, a diarylaminocarbonyl group which may have a substituent, a sulfonic acid group, an alkoxysulfonyl group which may have a substituent, an aryloxysulfonyl group which may have a substituent, an alkylsulfonyl group which may have a substituent, an arylsulfonyl group which may have a substituent, a sulfonamide group, a monoalkylaminosulfonyl group which may have a substituent, a dialkylaminosulfonyl group which may have a substituent, a monoarylaminosulfonyl group which may have a substituent, a diarylaminosulfonyl group which may have a substituent, an amino group, a monoalkylamino group which may have a substituent, a dialkylamino group which may have a substituent, an alkyl group which may have a substituent, an alkenyl group which may have a substituent, an alkynyl group which may have a substituent, an aryl group which may have a substituent, an alkoxy group which may have a substituent, an aryloxy group which may have a substituent, an alkylthio group which may have a substituent, an arylthio group which may have a substituent, a heterocyclic group which may have a substituent, etc. may be mentioned. Among these, from the viewpoint of stable operation, an alkyl group which may have a substituent, an alkoxy group which may have a substituent, a hydrogen atom, an aryl group which may have a substituent, an aryloxy group which may have a substituent, a halogen atom, an alkenyl group which may have a substituent, an alkynyl group which may have a substituent are preferable. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, and the like. Examples of the aryl group include a phenyl group, a naphthyl group, and the like. Examples of the aralkyl group include a benzyl group, a phenethyl group, a naphthylmethyl group, and the like. Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, and the like. Examples of the aryloxy group include a phenoxy group, a 1-naphthyloxy group, a 2-naphthyloxy group, a 4-methoxyphenoxy group, a 4-methylphenoxy group, and the like. Examples of the heterocyclic group include carbazole, dibenzofuran, dibenzothiophene, oxadiazole, thiadiazole, and the like. Examples of the substituent that is further substituted by the substituent include a halogen atom, a nitro group, a cyano group, an alkyl group such as a methyl group and an ethyl group, an alkoxy group such as a methoxy group and an ethoxy group, an aryloxy group such as a phenoxy group, an aryl group such as a phenyl group and a naphthyl group, an aralkyl group such as a benzyl group and a phenethyl group, and the like.

[0158] Specific examples of the compound (oxidative electrochromic compound) represented by the general formula 1 include compounds having structures shown below. The oxidative electrochromic compound is not limited thereto.

[0159] [Exemplary Compound 1] [Chemical formula]

[0160] [Exemplary Compound 2] [Chemical formula]

[0161] [Exemplary Compound 3] [Chemical formula]

[0162] [Exemplary Compound 4] [Chem.]

[0163] [Exemplary Compound 5] [Chem.]

[0164] [Exemplary Compound 6] [Chem.]

[0165] [Exemplary Compound 7] [Chem.]

[0166] [Exemplary Compound 8] [Chem.]

[0167] [Exemplary Compound 9] [Chem.]

[0168] [Exemplary Compound 10] [Chem.]

[0169] [Exemplary Compound 11] [Chem.]

[0170] [Exemplary Compound 12] [Chemical formula]

[0171] [Exemplary Compound 13] [Chemical formula]

[0172] [Exemplary Compound 14] [Chemical formula]

[0173] [Exemplary Compound 15] [Chemical formula]

[0174] [Exemplary Compound 16] [Chemical formula]

[0175] [Exemplary Compound 17] [Chemical formula]

[0176] [Exemplary Compound 18] [Chemical formula]

[0177] The voltage (threshold voltage) for causing the oxidation electrochromic compound to develop color can be determined by measuring the oxidation potential. There is no particular limitation on the method for measuring the oxidation potential, and it can be appropriately selected according to the purpose. For example, it can be measured by cyclic voltammetry.

[0178] The method for forming the oxidative electrochromic layer is not particularly limited and can be appropriately selected according to the purpose. When the oxidative electrochromic compound is an inorganic compound, examples thereof include a sputtering method, a vapor deposition method, application of nano-particles, an electro-deposition method, and the like. When the oxidative electrochromic compound is an organic compound, examples thereof include a method for forming a polymer film, a method for forming a structure supported on conductive or semiconductive fine particles, and the like.

[0179] Specific examples of the method for forming the polymer film include a method of dissolving a polymerized organic EC compound in a solvent, applying it to an electrode, and removing the solvent; a method of applying both an organic EC compound having a polymerizable functional group and a polymerization initiator to an electrode and polymerizing them. As the method for applying to the electrode, for example, various printing methods such as a spin coating method, a casting method, a micro gravure coating method, a gravure coating method, a bar coating method, a roll coating method, a wire bar coating method, a dip coating method, a slit coating method, a capillary coating method, a spray coating method, a nozzle coating method, a gravure printing method, a screen printing method, a flexographic printing method, an offset printing method, an intaglio printing method, an inkjet printing method can be used.

[0180] The average thickness of the oxidative electrochromic layer is not particularly limited and can be appropriately selected according to the purpose. However, it is preferably 0.1 μm or more and 30 μm or less, and more preferably 0.4 μm or more and 10 μm or less. When the average thickness is 0.1 μm or more, a deep coloring density is easily obtained. When it is 30 μm or less, the manufacturing cost can be suppressed, and further, a decrease in visibility due to coloring is less likely to occur.

[0181] - Reductive electrochromic layer - The reductive electrochromic layer is between the second electrode and the electrolyte layer and may be laminated on the second electrode. The reductive electrochromic layer may be laminated only in one layer or may be laminated in two or more layers.

[0182] The reducing electrochromic layer contains a reducing electrochromic compound. The reducing electrochromic compound is a compound in which the light absorption in the light wavelength region targeted by the electrochromic element changes by an electrochemical reduction reaction from the initial state. There is no particular limitation on the reducing electrochromic compound, and it can be appropriately selected according to the purpose, and it may be an inorganic compound or an organic compound. There is no particular limitation on the inorganic compound, and it can be appropriately selected according to the purpose. Examples include tungsten oxide, molybdenum oxide, iridium oxide, titanium oxide, and the like. These may be used alone or in combination of two or more. There is no particular limitation on the organic compound, and it can be appropriately selected according to the purpose. Examples include anthraquinone-based, viologen-based, thioindigo-based, terephthalic acid-based, and the like. Among these, viologen-based compounds are preferable from the viewpoints of durability and color tone. These may be used alone or in combination of two or more.

[0183] The reducing electrochromic layer can be formed in the same manner as the method for forming the oxidizing electrochromic layer described above.

[0184] The average thickness of the reducing electrochromic layer is preferably 0.1 μm or more and 30 μm or less, and more preferably 0.4 μm or more and 10 μm or less. When the average thickness is 0.1 μm or more, a deep color density is easily obtained. When it is 30 μm or less, the manufacturing cost can be suppressed, and furthermore, a decrease in visibility due to coloring is less likely to occur.

[0185] <Other members> There is no particular limitation on the other members, and they can be appropriately selected according to the purpose. Examples include a support (sometimes referred to as a substrate), an insulating porous layer, a deterioration prevention layer, a protective layer, and the like.

[0186] -Support- As the support, as long as it is formed of a transparent material capable of supporting each layer and has a structure capable of supporting each layer, there are no particular limitations on its shape, structure, size, material, etc., and it can be appropriately selected according to the purpose. The shape of the support is not particularly limited and can be appropriately selected according to the purpose. Examples include a flat plate shape and a shape having a curved surface. The material of the support only needs to be transparent, and well-known organic materials and inorganic materials can be used as they are. Examples include glass substrates such as non-alkali glass, borosilicate glass, float glass, and soda-lime glass, and resin substrates such as polycarbonate resin, acrylic resin, polyethylene, polyvinyl chloride, polyester, epoxy resin, melamine resin, phenol resin, polyurethane resin, and polyimide resin.

[0187] In addition, a transparent insulating layer, a UV cut layer, an antireflection layer, etc. may be provided on the surface of the support to enhance the water vapor barrier property, gas barrier property, UV resistance, and visibility.

[0188] -Insulating Porous Layer- The insulating porous layer functions to isolate the first electrode layer and the second electrode layer so that they are electrically insulated and to hold the electrolyte. The material of the insulating porous layer is not particularly limited as long as it is porous and can be appropriately selected according to the purpose. However, it is preferable to use organic materials, inorganic materials, and composites thereof that have high insulation and durability and excellent film-forming properties. The method for forming the insulating porous layer is not particularly limited and can be appropriately selected according to the purpose. Examples include a sintering method (using pores generated between particles by partially fusing polymer fine particles or inorganic particles with the addition of a binder, etc.), an extraction method (forming a layer with an organic or inorganic substance soluble in a solvent and a binder insoluble in the solvent, and then dissolving the organic or inorganic substance with the solvent to obtain pores), a foaming method of foaming, a phase inversion method of operating a good solvent and a poor solvent to phase-separate a mixture of polymers, a radiation irradiation method of irradiating various radiations to form pores, etc.

[0189] -Deterioration prevention layer- The role of the deterioration prevention layer is to undergo a chemical reaction opposite to that of the electrochromic layer, balance the charges, and suppress the corrosion and deterioration of the first electrode layer and the second electrode layer due to irreversible redox reactions. Note that the reverse reaction includes not only the case where the deterioration prevention layer undergoes redox reactions but also the case where it acts as a capacitor. The material of the deterioration prevention layer is not particularly limited as long as it can play a role in preventing the corrosion of the first electrode layer and the second electrode layer due to irreversible redox reactions, and can be appropriately selected according to the purpose. For example, stannic antimonate oxide, nickel oxide, titanium oxide, zinc oxide, tin oxide, or a conductive or semiconductive metal oxide containing a plurality of them can be mentioned. The deterioration prevention layer can be composed of a porous thin film that does not inhibit the injection of the electrolyte. For example, conductive or semiconductive metal oxide fine particles such as stannic antimonate oxide, nickel oxide, titanium oxide, zinc oxide, and tin oxide can be fixed to the second electrode by a binder such as an acrylic-based, alkyd-based, isocyanate-based, urethane-based, epoxy-based, or phenol-based binder to obtain a suitable porous thin film that satisfies the electrolyte permeability and the function as a deterioration prevention layer.

[0190] -Protection layer- The roles of the protection layer include, for example, protecting the element from external stress and chemicals in the cleaning process, preventing the leakage of the electrolyte, and preventing the intrusion of moisture, oxygen, etc. in the atmosphere that are unnecessary for the stable operation of the electrochromic element. The average thickness of the protection layer is not particularly limited and can be appropriately selected according to the purpose, but 1 μm to 200 μm is preferred. The material of the protection layer is not particularly limited and can be appropriately selected according to the purpose. For example, ultraviolet curable or thermosetting resins can be used. Specific examples of the protection layer include acrylic-based resins, urethane-based resins, epoxy-based resins, etc.

[0191] (Driving method of electrochromic element) The driving method of the electrochromic element of the present invention can be preferably performed by the electrochromic element of the present invention. The driving method of the electrochromic element of the present invention includes a step of applying a voltage higher than the threshold voltage Vc required for the electrochromic element to change from the initial state to the color change state to the electrochromic element, and a step of applying a voltage having a polarity opposite to that of the threshold voltage Vc, and further includes other steps as necessary.

[0192] The driving method includes a step (P1 step) of applying a voltage higher than the threshold voltage Vc required for the electrochromic element to change from the initial state to the color change state to the electrochromic element, and a step (P2 step) of applying a voltage having a polarity opposite to that of the threshold voltage Vc.

[0193] In the P1 step, a voltage higher than the threshold voltage Vc is applied between two electrodes in the electrochromic element. Thereby, an oxidation reaction in which the oxidative electrochromic compound exhibits electrochromism occurs, and the electrochromic element obtains a color change state from the initial state. In the P2 step, a voltage Vb having a polarity opposite to that of the threshold voltage Vc is applied. By applying the voltage Vb with the opposite polarity, the oxidation reaction of the oxidizable substance can be promoted, and the element can be quickly returned to the initial state. In the P2 step, the oxidative electrochromic compound, which is an oxidized product, undergoes a reduction reaction, and a part of the oxidation reaction paired with the reduction reaction is carried out by the oxidizable substance. Thereby, the electrochromic element returns from the color change state to the initial state. The redox reaction in the P2 step proceeds only as long as the oxidized form of the oxidative electrochromic compound remains. That is, it is not necessary to detect whether the oxidized form of the oxidative electrochromic compound exists, and the electrochromic element can be returned to the initial state by simply continuing to apply a voltage for returning the electrochromic element to the initial state.

[0194] The threshold voltage Vc is the difference between the potential at which a substance undergoes a reduction reaction at the reduction-side electrode and the potential at which a substance undergoes an oxidation reaction at the oxidation-side electrode in the electrochromic element. In the electrochromic element (complementary EC element) of the first aspect, the difference in redox potential between the oxidizing electrochromic compound and the reducing electrochromic compound is about 0.1 V lower. This is because the redox reaction occurs from a potential lower than the redox potential, resulting in a value about 0.05 V lower. Therefore, the combined value of both the oxidizing electrochromic compound and the reducing electrochromic compound is 0.1 V lower.

[0195] The threshold voltage Vc also varies depending on the material of the deterioration prevention layer. For example, in the electrochromic element (oxidation-type EC element) of the second aspect, when titanium oxide is used for the deterioration prevention layer, the reduction reaction of the titanium oxide occurs at about -0.7 V. Therefore, when an oxidizing electrochromic compound with a redox potential of 0.38 V is used, the threshold voltage Vc is about 1.0 V in combination with the redox potential of the oxidizing electrochromic compound. For example, in the electrochromic element (reduction-type EC element) of the third aspect, when an ATO film is used for the deterioration prevention layer, the ATO film does not undergo a redox reaction, but capacitive current characteristics can be obtained (charge amount = capacitance × voltage). In such an electrochromic element, a high voltage application is required to obtain a sufficient charge amount on the ATO side. Therefore, the voltage applied in the P1 process is a voltage higher than the threshold voltage Vc. The P1 process and the P2 process can be performed by applying a voltage waveform between both electrodes using a potentiostat.

Examples

[0196] Hereinafter, examples of the present invention will be described, but the present invention is not limited to these examples at all.

[0197] <Electrochemical measurement> Electrochemical measurements were performed on the following compounds. For the measurement of the oxidation-reduction potentials of the oxidative electrochromic compound and the reductive electrochromic compound, measurement solutions in which these compounds were dissolved in the electrolytic solution were used. As the electrolytic solution, a solution prepared by dissolving tetra-n-butylammonium perchlorate (manufactured by Tokyo Chemical Industry Co., Ltd.) at 100 mM in benzonitrile (manufactured by Tokyo Chemical Industry Co., Ltd.) was used. Compounds A, a triarylamine derivative which is an oxidative electrochromic compound, and Compound B, a viologen-based compound which is a reductive electrochromic compound, were each dissolved in this electrolytic solution at 5 mM to prepare respective measurement solutions for electrochemical measurement. The structures of Compound A and Compound B are shown below.

[0198] [Compound A] [Chemical formula]

[0199] [Compound B] [Chemical formula]

[0200] As the cell for performing the electrochemical measurement, a platinum disk electrode was used as the working electrode, a platinum wire was used as the counter electrode, and an Ag / Ag+ electrode was used as the reference electrode. The electrochemical measurement was performed using a potentiostat (ALS660C, manufactured by BAS Inc.), and the measurement method was cyclic voltammetry (CV). The measurement results are shown in Table 1. The oxidation potential of Compound A was 0.38 V, and the reduction potential of Compound B was -0.84 V.

[0201] Subsequently, the redox potential between the oxidizable substance and the reducible substance, and whether the redox reaction is an irreversible reaction were examined. As the electrolytic solution, the same one as that used for measuring the electrochromic compound was used. As the oxidizable substance and the reducible substance, the following Compounds 1 to 30 were dissolved in the electrolytic solution to a concentration of 5 mM to prepare each measurement solution.

[0202] [Compound 1] Butylferrocene (manufactured by Tokyo Chemical Industry Co., Ltd.) [Chemical formula]

[0203] [Compound 2] 2,2,6,6-Tetramethylpiperidine 1-Oxyl Free Radical (manufactured by Tokyo Chemical Industry Co., Ltd.) [Chemical formula]

[0204] [Compound 3] 2,6-Di-tert-butyl-4-methylphenol (manufactured by Tokyo Chemical Industry Co., Ltd.) [Chemical formula]

[0205] [Compound 4] Tripropylamine (manufactured by Tokyo Chemical Industry Co., Ltd.) [Chemical formula]

[0206] [Compound 5] Anthracene (manufactured by Tokyo Chemical Industry Co., Ltd.) [Chemical formula]

[0207] [Compound 6] Thianthrene (manufactured by Tokyo Chemical Industry Co., Ltd.) [Chem.]

[0208] [Compound 7] Triphenyl Phosphite (manufactured by Tokyo Chemical Industry Co., Ltd.) [Chem.]

[0209] [Compound 8] Triethyl Phosphite (manufactured by Tokyo Chemical Industry Co., Ltd.) [Chem.]

[0210] [Compound 9] Tris(2,4 - di - tert - butylphenyl) phosphite: Trade name SONGNOX1680 (manufactured by Sumitomo Chemical Co., Ltd.) [Chem.]

[0211] [Compound 10] 6 - [3 - (3 - tert - Butyl - 4 - hydroxy - 5 - methylphenyl) propoxy] - 2,4,8,10 - tetra - tert - butyldibenzo[d,f][1,3,2] dioxaphosphepin Trade name: Sumilizer GP (manufactured by Sumitomo Chemical Co., Ltd.) [Chem.]

[0212] [Compound 11] 4 - Ethyl - 4 - biphenylcarbonitrile (manufactured by Tokyo Chemical Industry Co., Ltd.) [Chem.]

[0213] [Compound 12] 1-Butyl-3-methylimidazolium Dibutyl Phosphate(manufactured by Tokyo Chemical Industry Co., Ltd.) [Chem.]

[0214] [Compound 13] 1,3-Dimethylimidazolium Dimethyl Phosphate(manufactured by Tokyo Chemical Industry Co., Ltd.) [Chem.]

[0215] [Compound 14] 1,3,5,7-Cyclooctatetraene(manufactured by Tokyo Chemical Industry Co., Ltd.) [Chem.]

[0216] [Compound 15] 1,3-Dimethoxybenzene(manufactured by Tokyo Chemical Industry Co., Ltd.) [Chem.]

[0217] [Compound 16] 2,5-Dimethoxytoluene(manufactured by Tokyo Chemical Industry Co., Ltd.) [Chem.]

[0218] [Compound 17] 2,4,5-Trimethoxybenzaldehyde(manufactured by Tokyo Chemical Industry Co., Ltd.) [Chemical formula]

[0219] [Compound 18] 1,3 - Diethoxybenzene (manufactured by Tokyo Chemical Industry Co., Ltd.) [Chemical formula]

[0220] [Compound 19] Tetracyanoquinodimethane (manufactured by Tokyo Chemical Industry Co., Ltd.) [Chemical formula]

[0221] [Compound 20] 1,4 - Benzoquinone (manufactured by Tokyo Chemical Industry Co., Ltd.) [Chemical formula]

[0222] [Compound 21] Chloranil (manufactured by Tokyo Chemical Industry Co., Ltd.) [Chemical formula]

[0223] [Compound 22] p - Tolquinone (manufactured by Tokyo Chemical Industry Co., Ltd.) [Chemical formula]

[0224] [Compound 23] Ethyl benzoate (manufactured by Tokyo Chemical Industry Co., Ltd.) [Chemical formula]

[0225] [Compound 24] 1,4-Diacetylbenzene (manufactured by Tokyo Chemical Industry Co., Ltd.)

Chem.

[0226] [Compound 25] Benzaldehyde (manufactured by Tokyo Chemical Industry Co., Ltd.)

Chem.

[0227] [Compound 26] Dimethyl maleate (manufactured by Tokyo Chemical Industry Co., Ltd.)

Chem.

[0228] [Compound 27] 2,3-Dimethylmaleic anhydride (manufactured by Tokyo Chemical Industry Co., Ltd.)

Chem.

[0229] [Compound 28] Succinic anhydride (manufactured by Tokyo Chemical Industry Co., Ltd.)

Chem.

[0230] [Compound 29] n-Octanoic anhydride (manufactured by Tokyo Chemical Industry Co., Ltd.)

Chem.

[0231] [Compound 30] Citraconic anhydride (manufactured by Tokyo Chemical Industry Co., Ltd.)

Chem.

[0232] For the electrochemical measurement device and the measurement cell, those similar to the measurement of electrochromic compounds were used. Also, the measurement of the oxidation-reduction potential was performed by the CV method in the same manner as for electrochromic compounds. The evaluation of the reversibility of the oxidation-reduction reaction was carried out by the double-step chronoamperometry (DSCA) method, which involves performing steps at a potential higher and lower than the oxidation-reduction potential. The evaluation of the oxidation-reduction potential was calculated from the half-wave potential, which is the midpoint between the peak potential of the oxidation current and the peak potential of the reduction current in the CV method. Since the oxidation-reduction reaction is irreversible, for substances where the oxidation-reduction current does not form a peak shape when returning to the initial state, the potential at which the oxidation-reduction current rises was used. The oxidation potential of the oxidizable substance was compared with that of Compound A, and the reduction potential of the reducible substance was compared with that of Compound B. The evaluation of the oxidation-reduction reaction used the ratio of currents in the DSCA method. In the DSCA method, for example, when the measurement target is a substance that undergoes an oxidation reaction and the oxidation reaction is reversible, the ratio of the oxidation current iox due to the constant potential step of the oxidation reaction and the reduction current ired of the constant potential step that reduces the oxidized form generated in this step is known to be the following formula (1). JPEG0007687074000148.jpg1972Here, in the above formula (1), t is the measurement time, and τ is the time of the constant potential step of the oxidation reaction. When both potential steps are the same time, the ratio of the oxidation current to the reduction current is 0.29. When the oxidation-reduction reaction is irreversible, this current ratio becomes smaller, and when the oxidized form does not return to the initial state at all, this current ratio becomes 0. Here, when the current ratio is 0.145 or less, which is half of 0.29, it was considered that the oxidation-reduction reaction is irreversible. The electrochemical measurement results are shown in Table 1.

[0233] [Table 1]

[0234] (Example 1) <Fabrication of an Oxidative Electrochromic Element> <<Fabrication of an Oxidative Electrochromic Layer>> To form an oxidative electrochromic layer on the first electrode, a solution with the following composition was prepared. [Composition] Oxidative electrochromic compound: 50 parts by mass of Compound A Ion conductor: 50 parts by mass of PEG400DA (manufactured by Nippon Kayaku Co., Ltd.) Polymerization initiator: 5 parts by mass of IRGACURE184 (manufactured by BASF) Solvent: 900 parts by mass of methyl ethyl ketone The obtained solution was applied to an ITO glass substrate (40 mm × 40 mm, thickness 0.7 mm, ITO film thickness: about 100 nm) as the first electrode by spin coating. The obtained coating film was irradiated with UV light at 10 mW for 60 seconds using a UV irradiation device (SPOT CURE, manufactured by USHIO Inc.), and annealed at 60 °C for 10 minutes to form an oxidative electrochromic layer with an average thickness of 1.3 μm.

[0235] <<Fabrication of a Degradation Prevention Layer>> An ITO glass substrate (40 mm × 40 mm, thickness 0.7 mm, ITO film thickness: about 100 nm) as the second electrode was coated with a titanium oxide nanoparticle dispersion (product name: SP210, manufactured by Showa Titanium Co., Ltd., average particle diameter: about 20 nm) as a degradation prevention layer by spin coating, and annealed at 120 °C for 15 minutes to fabricate a degradation prevention layer composed of a titanium oxide particle film with a thickness of 1.0 μm.

[0236] <<Formation of an Electrolyte Layer>> As monomers, 195 parts by weight of Brenmer AME400 (manufactured by NOF Corporation) and 195 parts by weight of Brenmer ADE400A (manufactured by NOF Corporation), 10 parts by weight of IRGACURE 184 (manufactured by BASF) as a polymerization initiator, 600 parts by weight of ethylmethylimidazolium bisfluorosulfonimide (trade name: EMIMFSI, manufactured by Kanto Chemical Co., Inc.) as an ionic liquid, and 50 parts by weight of Compound 3 as an oxidizable substance were mixed to obtain a monomer composition liquid. 30 mg of the obtained monomer composition liquid was measured with a micropipette and dropped onto an ITO glass substrate having a deterioration prevention layer to obtain an electrolyte layer composed of the monomer composition liquid.

[0237] [[Fabrication of Electrochromic Device]] An ITO glass substrate having an electrochromic layer and an ITO glass substrate having a deterioration prevention layer and an electrolyte layer were bonded together so that the electrochromic layer and the electrolyte layer were in contact with each other to obtain a bonded element. The obtained bonded element was irradiated with UV (wavelength 250 nm) at 10 mW for 60 seconds using a UV irradiation device (trade name: SPOT CURE, manufactured by USHIO Inc.) to fabricate the electrochromic device of Example 1.

[0238] (Examples 2 to 13) In Example 1, electrochromic devices of Examples 2 to 13 were fabricated in the same manner as in Example 1, except that the oxidizable substance in the electrolyte layer was replaced with each of the compounds shown in Table 2.

[0239] (Comparative Example 1) In Example 1, a comparative electrochromic device of Comparative Example 1 was fabricated in the same manner as in Example 1, except that no oxidizable substance was added to the electrolyte layer.

[0240] (Comparative Examples 2 to 6) In Example 1, electrochromic devices of Comparative Examples 2 to 6 were fabricated in the same manner as in Example 1, except that the oxidizable substance in the electrolyte layer was replaced with each of the compounds shown in Table 2.

[0241] <Evaluation of Oxidative Electrochromic Devices> For the electrochromic devices (oxidative electrochromic devices) of Examples 1 to 13 and Comparative Examples 1 to 6, memory property evaluation, color residue evaluation, and coloring density were evaluated. The threshold voltage Vc of the oxidative electrochromic device of the example was 1.0 V. In the following evaluations, the coloring voltage of the device was set to 1.2 V in order to obtain sufficient coloring. The evaluation results are shown in Table 2.

[0242] <Memory Property Evaluation> For each obtained electrochromic device, a constant voltage of 1.2 V was applied for 5 seconds, and then the circuit was opened. The absorbance at 730 nm immediately after opening the circuit and 30 minutes after starting to open the circuit was measured using an optical spectroscope (product name: USB4000, manufactured by Ocean Optics). Those in which the absorbance changed by applying a constant voltage could be maintained at 50% or more after 30 minutes were marked as "〇", and those that could not be maintained were marked as "×".

[0243] <Color Residue Evaluation> A constant voltage of 1.2 V was applied for 5 seconds, and subsequently, a constant voltage of -1.0 V was applied for 5 seconds as the voltage application step P2, and P1 and P2 were repeated alternately 100 times. After repeating 100 times, it was visually confirmed whether or not color residue of the electrochromic compound occurred. Those with color residue were marked as "×", and those without color residue were marked as "〇".

[0244] <Coloring Density> For the electrochromic devices in which no color residue occurred in the color residue evaluation, the absorbance at 730 nm was measured immediately after applying a constant voltage of 1.2 V for 5 seconds, and the influence of coloring density due to color residue removal was evaluated. Those in which the absorbance before the color residue evaluation could be maintained at 50% or more were marked as "○", and those that could not be maintained were marked as "×". Note that electrochromic devices with color residue were marked as "-" because they were not evaluable.

[0245]

Table 2

[0246] (Example 14) (Fabrication of Reduced-Type Electrochromic Element) (Formation of Degradation Prevention Layer) On the first electrode, a TFP dispersion of an aqueous polyurethane resin and ATO nanoparticles (manufactured by Mitsubishi Materials Corporation) was spin-coated, and a degradation prevention layer was formed by annealing at 120°C for 15 minutes.

[0247] (Fabrication of Reductive Electrochromic Layer) On an ITO glass substrate (40 mm × 40 mm, thickness 0.7 mm, ITO film thickness: about 100 nm) as the second electrode, a titanium oxide nanoparticle dispersion (product name: SP210, manufactured by Showa Titanium Co., Ltd., average particle diameter: about 20 nm) was applied by the spin-coating method. Then, by performing annealing treatment at 120°C for 15 minutes, a nanostructured semiconductor material composed of a titanium oxide particle film of about 1.0 μm was formed. Next, a 2,2,3,3-tetrafluoropropanol (hereinafter abbreviated as "TFP") solution containing 1% by mass of Compound B, which is a reductive electrochromic compound represented by the following structural formula, was applied onto the obtained titanium oxide particle film by the spin-coating method. Then, annealing treatment was performed at 120°C for 10 minutes. As described above, a reductive electrochromic layer composed of a titanium oxide particle film and a reductive electrochromic compound was formed.

[0248] [Compound B] [Chemical Formula]

[0249] (Fabrication of Electrolyte Layer) An electrolyte layer was formed in the same manner as in Example 1, except that the oxidizable substance in the electrolyte layer in the oxidized-type electrochromic element of Example 1 was replaced with Compound 25, which is a reducible substance.

[0250] <<Fabrication of Electrochromic Element>> An electrochromic element of Example 14 was fabricated in the same manner as the oxidized electrochromic element of Example 1.

[0251] (Examples 15 to 19) In Example 14, electrochromic elements of Examples 15 to 19 were fabricated in the same manner as Example 14, except that the reducible substance in the electrolyte layer was replaced with the compounds shown in Table 3.

[0252] (Comparative Example 7) In Example 14, an electrochromic element of Comparative Example 7 was fabricated in the same manner as Example 14, except that no reducible substance was added to the electrolyte layer.

[0253] (Comparative Examples 8 to 13) In Example 14, electrochromic elements of Comparative Examples 8 to 13 were fabricated in the same manner as Example 14, except that the oxidizable substances in the electrolyte layer were replaced with the compounds shown in Table 3, respectively.

[0254] <Evaluation of Reduced Electrochromic Element> For the electrochromic elements (reduced electrochromic elements) of Examples 14 to 19 and Comparative Examples 7 to 13, memory property evaluation, color residue evaluation, and coloring density were evaluated. The threshold voltage Vc of the reduced electrochromic element of the example was 0.5V. In the following evaluation, the coloring voltage of the element was set to 2.0V in order to obtain sufficient coloring. The evaluation results are shown in Table 3.

[0255] <Memory Property Evaluation> For each of the obtained electrochromic elements, a constant voltage of 2.0V was applied for 5 seconds, and then the circuit was opened. The absorbance at 610 nm immediately after opening the circuit and 30 minutes after starting to open the circuit was measured using an optical spectrometer (trade name: USB4000, manufactured by Ocean Optics). For those in which the absorbance changed by constant voltage application could be maintained at 50% or more after 30 minutes, it was marked as "〇", and for those that could not be maintained, it was marked as "×".

[0256] <Color residue evaluation> For the obtained electrochromic device, a constant voltage of 2.0 V was applied for 5 seconds as the voltage application step P1, and then a constant voltage of -1.0 V was applied for 5 seconds as the voltage application step P2, and P1 and P2 were repeated alternately 100 times. After repeating 100 times, it was visually confirmed whether or not color residue of the electrochromic compound occurred. Those with color residue were marked as "×", and those without color residue were marked as "〇".

[0257] <Color development density> For the electrochromic device in which no color residue occurred in the color residue evaluation, the absorbance at 610 nm was measured immediately after applying a constant voltage of 1.2 V for 5 seconds, and the influence of color residue removal on the color development density was evaluated. For those in which the absorbance before the color residue evaluation could be maintained at 50% or more, it was marked as "○", and for those that could not be maintained, it was marked as "×". Note that since the electrochromic device with color residue was not evaluable, it was marked as "-".

[0258]

Table 3

[0259] (Example 20) <Fabrication of complementary electrochromic device> In the same manner as in Example 1, an oxidative electrochromic layer was formed on the first electrode. In the same manner as in Example 14, a reductive electrochromic layer was formed on the second electrode.

[0260] <<Fabrication of electrolyte layer>> 195 parts by weight of Brenmer AME400 (manufactured by NOF Corporation), 195 parts by weight of Brenmer ADE400A (manufactured by NOF Corporation), 10 parts by weight of IRGACURE 184 (manufactured by BASF) as a polymerization initiator, 600 parts by weight of ethylmethylimidazolium bisfluorosulfonimide (trade name: EMIMFSI, manufactured by Kanto Chemical Co., Inc.) as an ionic liquid, and 50 parts by weight of Compound 3 as an oxidizable substance were mixed to obtain a monomer composition liquid. Next, 30 mg of the monomer composition liquid was measured with a micropipette and dropped onto an ITO glass substrate having a reducing electrochromic layer to obtain an electrolyte layer composed of the monomer composition liquid.

[0261] <<Fabrication of Electrochromic Device>> An ITO glass substrate having an oxidizing electrochromic layer and an ITO glass substrate having a reducing electrochromic layer and an electrolyte layer were bonded together so that the oxidizing electrochromic layer and the electrolyte layer were in contact with each other to obtain a bonded device. The obtained bonded device was irradiated with UV (wavelength 250 nm) at 10 mW for 60 seconds using a UV irradiation device (trade name: SPOT CURE, manufactured by USHIO INC.) to fabricate the electrochromic device of Example 20.

[0262] (Example 21) An electrochromic device of Example 21 was fabricated in the same manner as in Example 20, except that the oxidizable substance was replaced with the reducible substances shown in Tables 4 to 6.

[0263] (Example 22) An electrochromic device of Example 22 was fabricated in the same manner as in Example 20, except that 50 parts by weight of Compound 25 was added as a reducible substance to the electrolyte layer.

[0264] (Comparative Example 14) An electrochromic device of Comparative Example 14 was fabricated in the same manner as in Example 20, except that no oxidizable substance and reducible substance were added to the electrolyte layer.

[0265] (Comparative Examples 15 to 17) In Example 20, electrochromic devices of Comparative Examples 15 to 17 were each fabricated in the same manner as in Example 22, except that the oxidizable substance in the electrolyte layer was replaced with each of the compounds shown in Tables 4 to 6.

[0266] (Comparative Examples 18 to 19) In Example 21, electrochromic devices of Comparative Examples 18 to 19 were each fabricated in the same manner as in Example 21, except that the reducible substance in the electrolyte layer was replaced with each of the compounds shown in Tables 4 to 6.

[0267] (Comparative Examples 20 to 24) In Example 22, electrochromic devices of Comparative Examples 20 to 24 were each fabricated in the same manner as in Example 22, except that the oxidizable substance and the reducible substance in the electrolyte layer were replaced with each of the compounds shown in Tables 4 to 6.

[0268] (Evaluation of Complementary Electrochromic Device) The threshold voltage Vc of the complementary electrochromic device of the example was 1.1 V. In the following evaluation, the coloring voltage of the device was set to 1.5 V in order to obtain sufficient coloring.

[0269] (Memory Property Evaluation) A constant voltage of 1.5 V was applied to each of the obtained complementary electrochromic devices for 5 seconds, and then the circuit was opened. The absorbance at 610 nm immediately after opening the circuit and 30 minutes after starting to open the circuit was measured using an optical spectroscope (trade name: USB4000, manufactured by Ocean Optics). Those in which the absorbance changed by applying a constant voltage could be maintained at 50% or more after 30 minutes were marked as "〇", and those that could not be maintained were marked as "×".

[0270] (Evaluation 1: Color Retention) For the electrochromic devices (complementary electrochromic devices) of Example 20, Example 22, Comparative Examples 14 to 17, and Comparative Examples 20 to 24, the color residue was evaluated. For the obtained electrochromic device, a constant voltage of 1.5 V was applied for 5 seconds as the voltage application step P1, and then a constant voltage of -1.0 V was applied for 5 seconds as the voltage application step P2, and P1 and P2 were alternately repeated 100 times. After repeating 100 times, it was visually confirmed whether or not a color residue of the electrochromic compound occurred. The evaluation results are shown in Tables 4 to 6. Those with color residue were marked as "×", and those without color residue were marked as "〇". In Comparative Example 14 to which no oxidizable substance and reducible substance were added, color residue due to the oxidative electrochromic compound occurred in this evaluation. On the other hand, Examples 20 and 22 to which an oxidizable substance was added were able to eliminate the color residue that occurred in Comparative Example 14.

[0271] <<Evaluation 2: Color>> After the operation of the above Evaluation 1: color residue, a voltage of 1.5 V was applied for 5 seconds, and the color of the EC device was visually confirmed. When it was the same as the color before repetition, it was marked as "〇", and when it was different, it was marked as "×". The evaluation results are shown in Tables 4 to 6.

[0272] <<Evaluation 3: Color residue>> For the electrochromic devices (complementary electrochromic devices) of Examples 21 to 22 and Comparative Examples 18 to 24, the color residue was evaluated as follows. For the obtained electrochromic device, a constant voltage of 1.5 V was applied for 5 seconds as the voltage application step P1, and then a constant voltage of -1.0 V was applied for 5 seconds as the voltage application step P2, and P1 and P2 were alternately repeated 100 times. At this time, the electrochromic device was irradiated with simulated sunlight using a xenon tester (Q-SUN Xe-1, manufactured by Q-Lab Corporation). After repeating 100 times while irradiating with simulated sunlight, it was visually confirmed whether or not color residue of the electrochromic compound occurred. Those with color residue were marked as "×", and those without were marked as "〇". The evaluation results are shown in Tables 4 to 6. In Comparative Example 14 to which no oxidizable substance and reducible substance were added, color residue due to the reducing electrochromic compound occurred in this evaluation. On the other hand, Examples 21 to 22 to which a reducible substance was added were able to eliminate the color residue that occurred in Comparative Example 14.

[0273] <<Evaluation 4: Color>> After the color residue evaluation 3, a voltage of 1.5 V was applied for 5 seconds to confirm the color of the EC element. When it was the same as the color before repetition, it was marked as "〇", and when it was different, it was marked as "×". The evaluation results are shown in Tables 4 to 6.

[0274]

Table 4

[0275]

Table 5

[0276]

Table 6

[0277] As an aspect of the present invention, for example, it is as follows. <1>A first electrode, A second electrode provided to face the first electrode with a space therebetween, An electrolyte layer containing at least one of an oxidizable substance and a reducible substance between the first electrode and the second electrode, An oxidizing electrochromic layer containing an oxidizing electrochromic compound between the first electrode and the electrolyte layer, It has a reducing electrochromic layer containing a reducing electrochromic compound between the second electrode and the electrolyte layer. The oxidation potential of the oxidizable substance is nobler than the oxidation potential of the electrochromic compound. The reduction potential of the reducible substance is lower than the reduction potential of the electrochromic compound. The oxidation reaction of the oxidizable substance is irreversible. The electrochromic device is characterized in that the reduction reaction of the reducible substance is irreversible. <2>The electrochromic device according to <1>, wherein one or both of the oxidizable substance and the reducible substance are colorless and transparent. <3>The electrochromic device according to any one of <1> to <2>, wherein the oxidizable substance is at least one selected from phenols, alkoxybenzenes, cyanobenzenes, phosphites, phosphate salts, and annulenes. <4>The electrochromic device according to any one of <1> to <3>, wherein the reducible substance is at least one selected from acid anhydrides, aromatic ketones, and unsaturated fatty acid esters. <5>The electrochromic device according to any one of <1> to <4>, wherein the electrochromic compound is a triarylamine derivative. <6>A first electrode, A second electrode provided opposite to the first electrode with a space therebetween, An electrolyte layer containing an oxidizable substance between the first electrode and the second electrode, An electrochromic layer containing an electrochromic compound between the first electrode and the electrolyte layer, and The oxidation potential of the oxidizable substance is nobler than the oxidation potential of the electrochromic compound. The electrochromic device is characterized in that the oxidation reaction of the oxidizable substance is irreversible. <7>The electrochromic device according to <6>, wherein the oxidizable substance is colorless and transparent. <8>The electrochromic device according to any one of <6> to <7>, wherein the oxidizable substance is at least one selected from phenols, alkoxybenzenes, cyanobenzenes, phosphites, phosphate salts, and annulenes. <9>The electrochromic device according to any one of <6> to <8>, wherein the oxidative electrochromic compound is a triarylamine derivative. <10>A first electrode, A second electrode provided opposite to the first electrode with a space therebetween, An electrolyte layer containing a reducible substance between the first electrode and the second electrode, A reducing electrochromic layer containing a reducing electrochromic compound between the second electrode and the electrolyte layer, and having: The reduction potential of the reducible substance is lower than the reduction potential of the reducing electrochromic compound, The electrochromic device, wherein the reduction reaction of the reducible substance is irreversible. <11>The electrochromic device according to <10>, wherein the reducible substance is colorless and transparent. <12>The electrochromic device according to any one of <10> to <11>, wherein the reducible substance is at least one selected from acid anhydrides, aromatic ketones, and unsaturated fatty acid esters. <13>A first electrode, A second electrode provided opposite to the first electrode with a space therebetween, An electrolyte layer containing at least one of an oxidizable substance and a reducible substance between the first electrode and the second electrode, An oxidative electrochromic layer containing an oxidative electrochromic compound between the first electrode and the electrolyte layer, A reducing electrochromic layer containing a reducing electrochromic compound is provided between the second electrode and the electrolyte layer. For an electrochromic device having a step of applying a voltage greater than the threshold voltage Vc required for the electrochromic device to change from the initial state to the color change state; a step of applying a voltage having a polarity opposite to that of the threshold voltage Vc; A method for driving an electrochromic device, characterized by comprising the above steps. <14>A first electrode, a second electrode provided opposite to the first electrode with a space therebetween, an electrolyte layer containing an oxidizable substance provided between the first electrode and the second electrode, an oxidizing electrochromic layer containing an oxidizing electrochromic compound provided between the first electrode and the electrolyte layer, For an electrochromic device having a step of applying a voltage greater than the threshold voltage Vc required for the electrochromic device to change from the initial state to the color change state; a step of applying a voltage having a polarity opposite to that of the threshold voltage Vc; A method for driving an electrochromic device, characterized by comprising the above steps. <15>A first electrode, a second electrode provided opposite to the first electrode with a space therebetween, an electrolyte layer containing a reducible substance provided between the first electrode and the second electrode, a reducing electrochromic layer containing a reducing electrochromic compound provided between the second electrode and the electrolyte layer, For an electrochromic device having a step of applying a voltage greater than the threshold voltage Vc required for the electrochromic device to change from the initial state to the color change state; a step of applying a voltage having a polarity opposite to that of the threshold voltage Vc; A method for driving an electrochromic device, characterized by comprising the above steps.

[0278] According to the electrochromic element described in any one of <1> to <12> above and the driving method of the electrochromic element described in any one of <13> to <15> above, various problems in the prior art can be solved, and the object of the present invention can be achieved.

Explanation of Signs

[0279] 1 First electrode 2 Second electrode 5 Electrolyte layer 6 Oxidative electrochromic layer 9 Reductive electrochromic layer 201 Electrochromic element of the first aspect 202 Electrochromic element of the second aspect 203 Electrochromic element of the third aspect

Prior Art Documents

Patent Documents

[0280]

Patent Document 1

Patent Document 2

Claims

1. a first electrode; a second electrode provided to face the first electrode with a gap therebetween; an electrolyte layer containing at least one of an oxidizable substance and a reducible substance, disposed between the first electrode and the second electrode; an oxidative electrochromic layer containing an oxidative electrochromic compound, disposed between the first electrode and the electrolyte layer; a reductive electrochromic layer containing a reductive electrochromic compound, disposed between the second electrode and the electrolyte layer; and the oxidation potential of the oxidizable substance is nobler than the oxidation potential of the oxidative electrochromic compound; the reduction potential of the reducible substance is lower than the reduction potential of the reductive electrochromic compound; the oxidation reaction of the oxidizable substance is irreversible; the reduction reaction of the reducible substance is irreversible, and when a voltage greater than a threshold voltage Vc required for the electrochromic element to change from an initial state to a color change state is applied between the first electrode and the second electrode, the electrochromic element changes from the initial state to the color change state; when a constant voltage (excluding an alternating voltage) having a polarity opposite to that of the threshold voltage Vc is continuously applied between the first electrode and the second electrode, the electrochromic element changes from the color change state to the initial state.

2. The electrochromic element according to claim 1, wherein one or both of the oxidizable substance and the reducible substance are colorless and transparent.

3. The electrochromic element according to any one of claims 1 to 2, wherein the oxidizable substance is at least one selected from phenols, alkoxybenzenes, cyanobenzenes, phosphites, phosphate esters, and annulenes.

4. The electrochromic element according to any one of claims 1 to 3, wherein the reducible substance is at least one selected from acid anhydrides, aromatic ketones, and unsaturated fatty acid esters.

5. The electrochromic element according to any one of claims 1 to 4, wherein the oxidative electrochromic compound is a triarylamine derivative.

6. a first electrode; a second electrode provided to face the first electrode with a gap therebetween; an electrolyte layer containing an oxidizable substance, disposed between the first electrode and the second electrode; An electrochromic layer containing an oxidizing electrochromic compound is provided between the first electrode and the electrolyte layer. The oxidation potential of the substance to be oxidized is nobler than the oxidation potential of the oxidizing electrochromic compound. An electrochromic device in which the oxidation reaction of the substance to be oxidized is irreversible. When a voltage greater than the threshold voltage Vc required for the electrochromic device to change from the initial state to the color change state is applied between the first electrode and the second electrode, the device changes from the initial state to the color change state. An electrochromic device characterized in that when a constant voltage (excluding alternating voltage) having a polarity opposite to that of the threshold voltage Vc is continuously applied between the first electrode and the second electrode, the device changes from the color change state to the initial state. **Claim 7** The electrochromic device according to claim 6, wherein the substance to be oxidized is colorless and transparent. **Claim 8** The electrochromic device according to any one of claims 6 to 7, wherein the substance to be oxidized is at least one selected from phenols, alkoxybenzenes, cyanobenzenes, phosphites, phosphate salts, and annulenes. **Claim 9** The electrochromic device according to any one of claims 6 to 8, wherein the oxidizing electrochromic compound is a triarylamine derivative. **Claim 10** A first electrode A second electrode provided opposite to the first electrode with a gap therebetween. An electrolyte layer containing a substance to be reduced is provided between the first electrode and the second electrode. A reducing electrochromic layer containing a reducing electrochromic compound is provided between the second electrode and the electrolyte layer. The reduction potential of the substance to be reduced is lower than the reduction potential of the reducing electrochromic compound. An electrochromic device in which the reduction reaction of the substance to be reduced is irreversible. When a voltage greater than the threshold voltage Vc required for the electrochromic device to change from the initial state to the color change state is applied between the first electrode and the second electrode, the device changes from the initial state to the color change state. An electrochromic device characterized in that when a constant voltage (excluding alternating voltage) having a polarity opposite to that of the threshold voltage Vc is continuously applied between the first electrode and the second electrode, the device changes from the color change state to the initial state. **Claim 11** The electrochromic device according to claim 10, wherein the substance to be reduced is colorless and transparent.

12. The electrochromic device according to any one of claims 10 to 11, wherein the substance to be reduced is at least one selected from acid anhydrides, aromatic ketones, and unsaturated fatty acid esters.

13. A first electrode, A second electrode provided to face the first electrode with a space therebetween, An electrolyte layer containing at least one of an oxidizable substance and a reducible substance between the first electrode and the second electrode, An oxidizing electrochromic layer containing an oxidizing electrochromic compound between the first electrode and the electrolyte layer, A reducing electrochromic layer containing a reducing electrochromic compound between the second electrode and the electrolyte layer, For an electrochromic device having A step of applying a voltage greater than the threshold voltage Vc required for the electrochromic device to change from the initial state to the color change state, A step of continuously applying a constant voltage having a polarity opposite to that of the threshold voltage Vc (excluding an alternating voltage), A method for driving an electrochromic device, characterized by comprising the above steps.

14. A first electrode, A second electrode provided to face the first electrode with a space therebetween, An electrolyte layer containing an oxidizable substance between the first electrode and the second electrode, An oxidizing electrochromic layer containing an oxidizing electrochromic compound between the first electrode and the electrolyte layer, For an electrochromic device having A step of applying a voltage greater than the threshold voltage Vc required for the electrochromic device to change from the initial state to the color change state, A step of continuously applying a constant voltage having a polarity opposite to that of the threshold voltage Vc (excluding an alternating voltage), A method for driving an electrochromic device, characterized by comprising the above steps.

15. A first electrode, A second electrode provided to face the first electrode with a space therebetween, An electrolyte layer containing a reducible substance between the first electrode and the second electrode, A reducing electrochromic layer containing a reducing electrochromic compound between the second electrode and the electrolyte layer, For an electrochromic device having A step of applying a voltage greater than the threshold voltage Vc required for the electrochromic device to change from the initial state to the color change state, A step of continuously applying a constant voltage (excluding an alternating voltage) having a polarity opposite to that of the threshold voltage Vc; A method for driving an electrochromic element, characterized by comprising the step.

Images