JP2009300494A - Electrode for electrochemical display element and display element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrode for electrochemical display elements which has a simple member configuration and can be driven by a low voltage and is free from characteristic changes in repeated driving and has a high rewrite speed, and a display element using the same. <P>SOLUTION: The electrode for electrochemical display elements contains at least a carbon material and has a nitrogen-containing functional group aligned on a surface of the carbon material and has an auxiliary compound which can be electrochemically changed to the nitrogen-containing functional group by redox reaction, fixed thereto. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a novel electrode for an electrochemical display element and a display element using the same.

  In recent years, with the increase in the operating speed of personal computers, the spread of network infrastructure, the increase in capacity and price of data storage, information such as documents and images provided on printed paper on paper has become easier to use electronic information. Opportunities to obtain and browse electronic information are increasing more and more.

  As a means for browsing such electronic information, a conventional liquid crystal display or CRT, and in recent years, a light emitting type such as an organic EL display is mainly used. In particular, when the electronic information is document information, it is relatively long time. It is necessary to pay close attention to this browsing means, and these actions are not human-friendly means. Generally, as a disadvantage of the light-emitting display, flickering causes eye fatigue, inconvenience to carry, reading posture is limited, It is known that it is necessary to adjust the line of sight to a still screen, and that power consumption increases when read for a long time.

  As a display means to compensate for these drawbacks, a reflection type display using so-called "memory" that uses external light and does not consume power for image retention is known. However, it has sufficient performance for the following reasons. It is hard to say that it has.

  That is, the method using a polarizing plate such as a reflective liquid crystal has a low reflectance of about 40%, which makes it difficult to display white, and it is difficult to say that many of the manufacturing methods used to manufacture the constituent members are simple. In addition, the polymer dispersed liquid crystal requires a high voltage and utilizes the difference in refractive index between organic substances, so that the resulting image has insufficient contrast. In addition, the polymer network type liquid crystal has problems such as a high voltage and a complicated TFT circuit required to improve the memory performance. In addition, a display element based on electrophoresis requires a high voltage of 10 V or more, and there is a concern about durability due to electrophoretic particle aggregation.

  As a display method for solving the disadvantages of each of the above-mentioned methods, there are an electrochromic display element (hereinafter abbreviated as EC method) and an electrodeposition method (hereinafter abbreviated as ED method) using dissolution precipitation of metal or metal salt. Are known. The EC method has the advantage of being capable of full-color display at a low voltage of 3V or less, a simple cell configuration, and excellent white quality. The ED method can also be driven at a low voltage of 3V or less and is a simple cell. There are advantages such as excellent configuration, black-to-white contrast and black quality, and various methods are disclosed (for example, see Patent Documents 1 to 5).

  As a problem of the ED method or EC method, there is a problem that the characteristics of the electrode change when it is repeatedly driven. Further, as another problem, it has been necessary to improve the rewriting speed of the display screen in order to expand the application.

  With respect to the problem that the characteristics of the electrode change when it is repeatedly driven, studies have been made to improve it by improving the durability of the electrode by using a carbon material as the electrode material (see, for example, Patent Document 6). .)

As a result of examining the technique disclosed in Patent Document 6 in detail, the present inventor has an effect of improving the characteristics of the electrode when the electrode is made of a carbon material when it is repeatedly driven. It has been found that further improvement is necessary for the screen rewriting speed.
WO2004 / 068231 Specification WO 2004/066773 specification U.S. Pat. No. 4,240,716 Japanese Patent No. 3428603 JP 2007-72368 A JP 2008-19120 A

  The present invention has been made in view of the above problems, and its purpose is to provide an electrode for an electrochemical display element that has a simple member configuration, can be driven at a low voltage, has little characteristic change in repeated driving, and has a fast rewriting speed. And providing a display element using the same.

  The above object of the present invention is achieved by the following configurations.

  1. Electricity characterized in that it contains at least a carbon material, nitrogen-containing functional groups are oriented on the surface of the carbon material, and auxiliary compounds that can be electrochemically oxidized and reduced are immobilized on the nitrogen-containing functional groups. Electrode for chemical display element.

  2. 2. The electrode for an electrochemical display element as described in 1 above, wherein an aqueous solution containing carbamic acid is electrolytically oxidized with a carbon electrode to orient a nitrogen-containing functional group on the surface of the carbon material.

  3. 3. The electrode for an electrochemical display element according to 1 or 2, wherein the nitrogen-containing functional group is an amino group.

  4). 4. The electrochemical display element according to any one of 1 to 3, wherein the carbon material is at least one selected from glassy carbon, carbon nanotube, carbon felt, plastic molded carbon, and diamond. electrode.

  5). Any one of the above 2 to 4, wherein the aqueous solution containing carbamic acid is at least one selected from an aqueous solution of ammonium carbamate, an aqueous solution of ammonium carbonate containing carbamic acid, and an aqueous solution of ammonium bicarbonate containing carbamic acid. The electrode for an electrochemical display element described in the item.

  6). 6. The electrode for an electrochemical display element according to any one of 1 to 5, wherein the auxiliary compound that can be electrochemically oxidized and reduced is a counter electrode reactant.

  7. 7. The electrode for an electrochemical display element as described in 6 above, wherein the counter electrode reactant is an N-oxyl derivative.

  8). 7. The electrode for an electrochemical display element as described in 6 above, wherein the counter electrode reactant is a metal complex having a compound represented by the following general formula [I] as an organic ligand.

[Wherein R ₃₁ , R ₃₂ , R ₃₃ and R ₃₄ are each independently a hydrogen atom, amino group, hydroxy group, mercapto group, alkoxy group, alkyl group, alkenyl group, alkynyl group, aryl group or heterocyclic group. These substituents may further have a substituent. R ₃₁ and R ₃₂ , R ₃₂ and R _33, and R ₃₃ and R ₃₄ may be connected to each other to form an aromatic or non-aromatic cyclic structure, and a substituent is present at any position on the ring. You may have. ]
9. The electrode for an electrochemical display element according to any one of 1 to 8 above, wherein the counter electrode includes an electrolyte layer containing a metal salt compound and a white scatterer, and at least one of the counter electrodes is the electrode for an electrochemical display element according to any one of 1 to 8 above. A display element which displays black and white by applying a voltage between the counter electrodes.

  10. 10. The display element according to 9, wherein the metal salt compound is a silver salt compound.

  11. 11. The display element according to 9 or 10, wherein the electrolyte layer contains a compound represented by the following general formula (G-1) or (G-2).

General formula (G-1)
_{Rg 11} -S-Rg ₁₂
[Wherein, Rg ₁₁ and Rg ₁₂ each represent a substituted or unsubstituted hydrocarbon group. Further, these hydrocarbon groups may contain one or more nitrogen atom, oxygen atom, phosphorus atom, sulfur atom or halogen atom, and Rg ₁₁ and Rg ₁₂ may be connected to each other to take a cyclic structure. ]

[Wherein, M represents a hydrogen atom, a metal atom or quaternary ammonium. Z represents an atomic group necessary for constituting a nitrogen-containing heterocyclic ring. n represents an integer of 0 to 5, Rg ₂₁ represents a substituent, and when n is 2 or more, each Rg ₂₁ may be the same or different, and may be connected to each other to form a condensed ring. It may be formed. ]
12 Between the counter electrodes, an electrochromic compound, an electrolyte layer, and a white scattering layer, and at least one of the counter electrodes is the electrode for an electrochemical display element according to any one of 1 to 8, A display element that displays a colored display other than black and white by applying a voltage between the counter electrodes.

  13. 13. The display element as described in 12 above, wherein the electrochromic compound is a compound represented by the following general formula (L).

[Wherein, Rl ₁ represents a substituted or unsubstituted aryl group, and Rl ₂ and Rl ₃ each represent a hydrogen atom or a substituent. X represents> N—Rl ₄ , an oxygen atom or a sulfur atom, and Rl ₄ represents a hydrogen atom or a substituent. ]
14 The compound represented by the said general formula (L) is -COOH, -P = O (OH) ₂ , -OP = O (OH) _2, and -Si (OR) ₃ (R represents an alkyl group.) 14. The display element as described in 13 above, which has at least one group selected from the group consisting of:

  15. 15. The display element according to the item 13 or 14, wherein the compound represented by the general formula (L) is immobilized on an electrode surface.

  16. The electrochemical display according to any one of 1 to 8, wherein an electrochromic compound, an electrolyte layer containing a metal salt compound and a white scattering layer are provided between the counter electrodes, and at least one of the counter electrodes is one of the above 1 to 8. A display element which is an element electrode and displays a colored display other than black and white by applying a voltage between the counter electrodes.

  17. 17. The display device as described in 16 above, wherein the metal salt compound is a silver salt compound.

  18. The display element according to 16 or 17, wherein the electrolyte layer contains a compound represented by the following general formula (G-1) or (G-2).

General formula (G-1)
_{Rg 11} -S-Rg ₁₂
[Wherein, Rg ₁₁ and Rg ₁₂ each represent a substituted or unsubstituted hydrocarbon group. Further, these hydrocarbon groups may contain one or more nitrogen atom, oxygen atom, phosphorus atom, sulfur atom or halogen atom, and Rg ₁₁ and Rg ₁₂ may be connected to each other to take a cyclic structure. ]

[Wherein, M represents a hydrogen atom, a metal atom or quaternary ammonium. Z represents an atomic group necessary for constituting a nitrogen-containing heterocyclic ring. n represents an integer of 0 to 5, Rg ₂₁ represents a substituent, and when n is 2 or more, each Rg ₂₁ may be the same or different, and may be connected to each other to form a condensed ring. It may be formed. ]
19. 19. The display element according to any one of 16 to 18, wherein the electrochromic compound is a compound represented by the following general formula (L).

[Wherein, Rl ₁ represents a substituted or unsubstituted aryl group, and Rl ₂ and Rl ₃ each represent a hydrogen atom or a substituent. X represents> N—Rl ₄ , an oxygen atom or a sulfur atom, and Rl ₄ represents a hydrogen atom or a substituent. ]
20. The compound represented by the said general formula (L) is -COOH, -P = O (OH) ₂ , -OP = O (OH) _2, and -Si (OR) ₃ (R represents an alkyl group.) 20. The display element as described in 19 above, which has at least one group selected from the group consisting of:

  21. 21. The display element as described in 19 or 20 above, wherein the compound represented by the general formula (L) is immobilized on an electrode surface.

  According to the present invention, it was possible to provide an electrode for an electrochemical display element that can be driven with a simple member configuration, low voltage, has little characteristic change in repeated driving, and has a high rewrite speed, and a display element using the same. .

  Hereinafter, the best mode for carrying out the present invention will be described in detail.

  As a result of intensive studies in view of the above problems, the present inventor 1) contains at least a carbon material, a nitrogen-containing functional group is oriented on the surface of the carbon material, and is electrochemically oxidized to the nitrogen functional group. Electrode for an electrochemical display element characterized in that an auxiliary compound that can be reduced is immobilized, 2) Between the counter electrode, an electrolyte layer containing a metal salt compound and a white scatterer, and the counter electrode Wherein at least one of the electrodes is an electrode for an electrochemical display element according to the above item 1) of the present invention, and black and white are displayed by applying a voltage between the counter electrodes. Element, or 3) having an electrolyte layer containing a metal salt compound and a white scatterer between the counter electrodes, and at least one of the counter electrodes is for the electrochemical display element according to item 1) of the present invention An electrode and the opposite A display element characterized by displaying black and white by applying a voltage between the electrodes, can be driven with a simple member configuration, low voltage, little characteristic change in repeated driving, and high rewriting speed It has been found that an electrode for an electrochemical display element and a display element using the same can be realized, and the present invention has been achieved.

  Details of the present invention will be described below.

[Basic structure of display element]
In the display element of the present invention, the display portion is provided with one corresponding counter electrode. A transparent electrode such as an ITO electrode is fixed to the electrode 1 which is one of the counter electrodes close to the display portion, and an electrochemically active compound is fixed to the other electrode 2 via the nitrogen-containing functional group according to the present invention. A conductive electrode made of a carbon material is provided. Between the electrode 1 and the electrode 2, an electrolyte layer containing a metal salt compound and a white scattering layer are provided. By applying a voltage of both positive and negative polarities between the counter electrodes, the white display and the black display are reversible. Can be switched.

[Carbon material]
The carbon material according to the present invention is preferably a carbon material such as graphite having conductivity, and among them, glassy carbon, carbon nanotube, carbon felt, plastic molded carbon, or diamond electrode is more preferable.

[Nitrogen-containing functional group]
The electrode for an electrochemical display element of the present invention contains the above carbon material, and a nitrogen-containing functional group is oriented on the surface of the carbon material.

  The nitrogen-containing functional group according to the present invention may be any group containing nitrogen in the chemical structure, such as an amide group, amino group, imino group, ureido group, enamine group, oxime group, nitrile group, nitro group, lactam. Groups and the like. An amino group is preferred as the nitrogen-containing functional group that satisfies the effects of the present invention.

[Electrodes composed of carbon materials with nitrogen-containing functional groups]
An electrode composed of a carbon material having a nitrogen-containing functional group bonded thereto according to the present invention is obtained by electrolytically oxidizing an aqueous solution containing carbamic acid using a carbon electrode and covalently bonding the nitrogen-containing functional group to the surface of the carbon electrode. It is formed by. In the method for producing an electrode material, the nitrogen-containing functional group is preferably an amino group. In the method for producing the electrode material, the aqueous solution containing carbamic acid is preferably ammonium carbamate, ammonium carbonate containing carbamic acid, or ammonium hydrogen carbonate containing carbamic acid.

  In an electrode composed of a carbon material to which a nitrogen-containing functional group is bonded according to the present invention, an auxiliary compound that can be electrochemically oxidized / reduced is immobilized on the nitrogen-containing functional group, thereby reducing deterioration of the electrode due to repeated driving. A display element with high rewriting speed can be provided.

  The electrode made of a carbon material to which a nitrogen-containing functional group is bonded according to the present invention is an electrode material having improved redox characteristics by covalently bonding the nitrogen-containing functional group to a carbon atom on the surface of the carbon material. It is said.

  As an embodiment of the electrode material according to the present invention, the nitrogen-containing functional group is preferably an amino group. Further, this amino group may be oxidized to form a nitro group or a nitroso group. In order to covalently bond the amino group to the carbon atom on the surface of the carbon material, the carbamic acid is directly covalently bonded to the carbon atom on the surface of the carbon material by electrolytic oxidation of an aqueous solution containing carbamic acid using the carbon material as an electrode. A method of decarboxylating and introducing an amino group directly into a carbon atom on the surface of the carbon material by a covalent bond is preferable.

  An example of a structure in which an amino group is directly covalently bonded to a carbon atom on the surface of a carbon material as described above is shown below.

  As shown in the above structural formula, in addition to amino groups, oxygen-containing functional groups such as hydroxyl groups and carboxylic acids are bonded to the surface of the carbon material.

[Auxiliary compounds that can be oxidized and reduced electrochemically]
In the display device of the present invention, an auxiliary compound (hereinafter referred to as a promoter) that can be oxidized and reduced may be added in order to promote the electrochemical reaction of the compound that reversibly changes color due to the electrochemical redox reaction. preferable. The promoter may be one that does not change the optical density in the visible region (400 to 700 nm) as a result of the oxidation-reduction reaction, or one that changes, that is, a compound that reversibly discolors due to the electrochemical oxidation-reduction reaction. Alternatively, it may be fixed on the electrode, or may be added to the electrolyte. These promoters can be used, for example, as counter electrode reactants or as redox mediators.

  For example, when a compound that reversibly changes color due to an electrochemical redox reaction on the display electrode side is oxidized (or reduced), a low drive is achieved by utilizing the reduction (or oxidation) reaction of the promoter on the counter electrode side. It is possible to obtain a high color density with voltage. Thus, when a promoter is used as a counter electrode reactant, it is preferable to use a promoter having a redox activity opposite to that of a compound reversibly discolored by an electrochemical redox reaction, immobilized on a counter electrode. . When a promoter is used as a counter electrode material, it is preferable that the promoter does not change the optical density in the visible region (400 to 700 nm) as a result of the redox reaction. However, as described in the preferred embodiment of the present invention, in the embodiment in which white scatterers are used in the display element to block color development by the promoter, the promoter in which the optical density in the visible region (400 to 700 nm) changes. That is, a compound that changes color reversibly by an electrochemical redox reaction may be used. Such a configuration is preferable because it facilitates selection of a promoter. As another embodiment, it is one of preferred embodiments to use a promoter that exhibits the same color as a compound that reversibly changes color by an electrochemical redox reaction on the display electrode side.

  On the other hand, the redox mediator is a material generally used in the field of organic electrolytic synthesis. Each organic compound has an oxidation overvoltage that depends on the electrolysis method and electrolysis conditions, in addition to its own oxidation potential, and when the anode potential is higher than the combined oxidation potential, an oxidation reaction actually occurs. Due to experimental limitations on the anodic potential, it is not possible to oxidize all substrates by direct methods. When a substrate having a high oxidation potential is oxidized, no electron transfer from the substrate to the anode occurs. When a mediator that causes electron transfer (oxidation) to the anode at a low potential coexists in this reaction system, the mediator is first oxidized, and the substrate is oxidized by the oxidized mediator to obtain a product. The advantage of this reaction system is that it is possible to oxidize the substrate at an anodic potential lower than the oxidation potential of the substrate, and that the oxidized mediator returns to the original mediator when the substrate is oxidized. It acts as a catalytic amount. Further, since oxidation at a low potential is possible, decomposition of the substrate and product can be suppressed.

  In the present invention, for example, when a compound that reversibly discolors by an electrochemical redox reaction that oxidizes and develops as the substrate, the display element is driven at a low driving voltage by coexisting a catalytic amount of an oxidation mediator. The durability of the display element is increased. Further, there are advantages such as an improvement in display switching speed and high color development efficiency. Similarly, the above effect can be obtained by a combination of a reducing mediator and a compound that reversibly discolors by an electrochemical redox reaction that produces a reduction color.

  In the display element of the present invention, as shown in the field of organic electrolytic synthesis, a single mediator may be used, or a plurality of mediators may be used in combination. When a promoter is used as a mediator in the present invention, it is preferable to fix a compound that changes color reversibly by an electrochemical redox reaction on a display electrode and to localize the promoter in the vicinity thereof.

  In the present invention, a promoter may be used as a counter electrode reactant or a mediator. For both purposes, a plurality of promoters may be used in combination at the same time.

  There is no restriction | limiting in particular as a promoter, According to the objective, it can select suitably. In particular, when used as a counter electrode reactant, it is possible to use a compound that reversibly discolors by a known electrochemical redox reaction. In addition, when used as a redox mediator, in accordance with the properties of a compound that reversibly changes color by an electrochemical redox reaction, Journal of Synthetic Organic Chemistry, Vol. 43, No. 6 (“Organic synthesis using electric energy”). The known mediators described in “Special Issue” (1985) and the like can be appropriately selected and used.

  Preferred promoters that can be used in the present invention include, for example, the following compounds.

1) N-oxyl derivatives such as TEMPO (2,2,6,6-tetramethylpiperidinyl-N-oxyl), N-hydroxyphthalimide derivatives, hydroxamic acid derivatives, etc., compounds having an N—O bond ,
2) a compound having an allyloxy free radical having a bulky substituent introduced at the 0-position, such as galvinoxyl;
3) metallocene derivatives such as ferrocene,
4) benzyl (diphenylethanedione) derivative,
5) Tetrazolium salt / formazan derivative,
6) Azine compounds such as phenazine, phenothiazine, phenoxazine, acridine,
7) pyridinium compounds such as viologen,
In addition, hydrazyl free radical compounds such as benzoquinone derivatives, verdazyl, thiazyl free radical compounds, hydrazone derivatives, phenylenediamine derivatives, triallylamine derivatives, tetrathiafulvalene derivatives, tetracyanoquinodimethane derivatives, thianthrene derivatives, etc. can also be used as promoters. .

  In the display element of the present invention, promoters in the categories 1) to 7) are preferable, and 1) is particularly preferable.

  Hereinafter, compounds in the category 1) will be described in detail.

  N-oxyl (also called nitroxide radical) is an oxygen-centered radical generated by radically cleaving the oxygen-hydrogen bond of hydroxylamine. Nitroxide radicals are known to have two reversible redox pairs as shown in the scheme below. The nitroxide radical becomes an oxoammonium cation by one-electron oxidation, which is reduced to regenerate the radical. The nitroxide radical is converted into an aminoxy anion by one-electron reduction, which is oxidized to regenerate the radical. Therefore, the nitroxide radical can function as a p-type counter electrode reactant or an n-type counter electrode reactant. In addition, oxoammonium cation has a high oxidation ability and can function as a mediator because it can oxidize leuco dyes and the like.

  The N-oxyl derivative may be contained in the electrolyte or may be immobilized on the electrode surface. Examples of the method of immobilizing on the electrode surface include a method of introducing a group that chemically or physically adsorbs with the electrode surface into the N-oxyl derivative, a method of forming a thin film on the electrode surface by polymerizing the N-oxyl derivative It is done. The N-oxyl derivative may be added in the form of an N-oxyl radical, or may be added in the form of an N-hydroxy compound, and further in the form of an oxoammonium cation.

  As N-oxyl derivatives, derivatives substituted with various substituents such as TEMPO (2,2,6,6-tetramethylpiperidinyl-N-oxyl) are commercially available. In addition, various derivatives including polymers can be easily synthesized according to known literature.

  In general, it is known that when hydrogen is substituted on the α-position carbon of the nitroxide radical, it is easily disproportionated to hydroxyamine and nitrone. For this reason, the four methyl groups at the N-oxyl group α-position of TEMPO can be said to be indispensable structures when present as stable radicals, but conversely, when the reactivity falls due to the steric hindrance of these four methyl groups. There is. Azaadamantane N-oxyl derivatives or azabicyclo N-oxyl derivatives are preferred in that they do not cause a decrease in activity.

  Next, N-hydroxyphthalimide derivatives, hydroxamic acid derivatives and the like will be described. As shown in the following scheme, phthalimide N-oxyl (PINO) generated by electrode oxidation of N-hydroxyphthalimide (NHPI) oxidizes a secondary alcohol to produce a ketone. That is, it has been reported that NHPI functions as an oxidation mediator (Chem. Commun., 1983, 479.). As can be seen from this example, it is understood that the redox couple of NHPI / PINO functions as a counter electrode reactant or mediator also in the display element of the present invention. As with NHPI, hydroxamic acid derivatives and trihydroxyimino cyanuric acid (THICA) can also be used as promoters.

  When the display element of the present invention is manufactured using these compounds, it is preferably added in the state of N—OH. After a display element is manufactured in the state of N—OH, radicals are generated by driving the display element to oxidize.

  The promoter represented by the category 1) can be represented by the following general formula (M1), and promoters represented by the following general formulas (M2) to (M6) are preferable. In particular, a polycyclic N-oxyl derivative represented by the general formula (M6) is preferable. Various promoters represented by the general formulas (M1) to (M5) are commercially available and can be easily obtained. Various derivatives can be easily synthesized according to known literature. The promoter represented by the general formula (M6) is J.P. Am. Chem. Soc. , 128, 8412 (2006) and Tetrahedron Letters 49 (2008) 48-52.

  Further, promoters obtained by polymerizing these are disclosed in, for example, JP-A Nos. 2004-227946, 2004-228008, 2006-73240, 2007-35375, 2007-70384, and 2007. -184227, 2007-298713, and the like.

  First, the compound represented by general formula (M1) is demonstrated.

In the general formula (M1), Rm ₁₁ and Rm ₁₂ are each independently an aliphatic hydrocarbon group, an aromatic hydrocarbon group, a heterocyclic group or>C═O,> C═S, which may have a substituent. ,> C = N—Rm represents a group bonded to a nitrogen atom via ₁₃ . Rm ₁₃ represents a hydrogen atom or an aliphatic hydrocarbon group, an aromatic hydrocarbon group or a heterocyclic group which may have a substituent. Rm ₁₁ and Rm ₁₂ may be connected to each other to form a cyclic structure.

  The aliphatic hydrocarbon group includes chain and cyclic groups, and the chain group includes linear and branched groups. Such aliphatic hydrocarbon groups include methyl, ethyl, vinyl, propyl, isopropyl, propenyl, butyl, iso-butyl, tert-butyl, pentyl, isopentyl, neopentyl, hexyl, iso-hexyl, cyclohexyl, cyclohexenyl, Examples include octyl, iso-octyl, cyclooctyl, 2,3-dimethyl-2-butyl and the like.

  Examples of the aromatic hydrocarbon group include a phenyl group and a naphthyl group. Examples of the heterocyclic group include a pyridyl group, a thiazolyl group, an oxazolyl group, an imidazolyl group, a furyl group, a pyrrolyl group, a pyrazinyl group, a pyrimidinyl group, and a pyridazinyl group. , Serenazolyl group, sulfolanyl group, piperidinyl group, pyrazolyl group, tetrazolyl group, morpholino group and the like.

  These substituents may further have a substituent. These substituents are not particularly limited, and examples thereof include alkyl groups (for example, methyl group, ethyl group, propyl group, isopropyl group, tert-butyl group, pentyl group, hexyl group, octyl group, dodecyl group, tridecyl group, Tetradecyl group, pentadecyl group etc.), cycloalkyl group (eg cyclopropyl group, cyclopentyl group, cyclohexyl group etc.), alkenyl group (eg vinyl group, allyl group, butenyl group, octenyl group etc.), cycloalkenyl group (eg , 2-cyclopenten-1-yl group, 2-cyclohexen-1-yl group, etc.), alkynyl group (eg, propargyl group, ethynyl group, trimethylsilylethynyl group, etc.), aryl group (eg, phenyl group, naphthyl group, p) -Tolyl group, m-chlorophenyl group, o-hexadecanoylamino Phenyl group, etc.), heterocyclic group (for example, pyridyl group, thiazolyl group, oxazolyl group, imidazolyl group, furyl group, pyrrolyl group, pyrazinyl group, pyrimidinyl group, pyridazinyl group, selenazolyl group, sulfolanyl group, piperidinyl group, pyrazolyl group, Tetrazolyl group, morpholino group, etc.), heterocyclic oxy group (for example, 1-phenyltetrazol-5-oxy group, 2-tetrahydropyranyloxy group, pyridyloxy group, thiazolyloxy group, oxazolyloxy group, imidazolyloxy group, etc.) ), Halogen atoms (for example, chlorine atom, bromine atom, iodine atom, fluorine atom, etc.), alkoxy groups (for example, methoxy group, ethoxy group, propyloxy group, tert-butoxy group, pentyloxy group, hexyloxy group, octyl) Oxy group, dodecyloxy Group), cycloalkoxy group (for example, cyclopentyloxy group, cyclohexyloxy group, etc.), aryloxy group (for example, phenoxy group, 2-naphthyloxy group, 2-methylphenoxy group, 4-tert-butylphenoxy group, 3 -Nitrophenoxy group, 2-tetradecanoylaminophenoxy group, etc.), alkylthio group (eg, methylthio group, ethylthio group, propylthio group, pentylthio group, hexylthio group, octylthio group, dodecylthio group, etc.), cycloalkylthio group (eg, Cyclopentylthio group, cyclohexylthio group, etc.), arylthio group (for example, phenylthio group, 1-naphthylthio group, etc.), heterocyclic thio group (for example, pyridylthio group, thiazolylthio group, oxazolylthio group, imidazolylthio group, furylthio group, pinyl) Rorylthio group, etc.), alkoxycarbonyl group (eg, methoxycarbonyl group, ethoxycarbonyl group, butoxycarbonyl group, octyloxycarbonyl group, dodecyloxycarbonyl group, etc.), aryloxycarbonyl group (eg, phenyloxycarbonyl group, naphthyloxycarbonyl) Group), sulfamoyl group (for example, aminosulfonyl group, methylaminosulfonyl group, dimethylaminosulfonyl group, butylaminosulfonyl group, hexylaminosulfonyl group, cyclohexylaminosulfonyl group, octylaminosulfonyl group, dodecylaminosulfonyl group, phenylamino) Sulfonyl group, naphthylaminosulfonyl group, 2-pyridylaminosulfonyl group, morpholinosulfonyl group, pyrrolidinosulfonyl group, etc.), ureido (For example, methylureido group, ethylureido group, pentylureido group, cyclohexylureido group, octylureido group, dodecylureido group, phenylureido group, naphthylureido group, 2-pyridylaminoureido group, etc.), acyl group (for example, acetyl group Ethylcarbonyl group, propylcarbonyl group, pentylcarbonyl group, cyclohexylcarbonyl group, octylcarbonyl group, 2-ethylhexylcarbonyl group, dodecylcarbonyl group, phenylcarbonyl group, naphthylcarbonyl group, pyridylcarbonyl group, etc.), acyloxy group (for example, Formyloxy, acetyloxy, pivaloyloxy, stearoyloxy, benzoyloxy, p-methoxyphenylcarbonyloxy, ethylcarbonyloxy, Rucarbonyloxy group, octylcarbonyloxy group, dodecylcarbonyloxy group, phenylcarbonyloxy group, etc.), acylamino group (for example, acetylamino group, benzoylamino group, formylamino group, pivaloylamino group, lauroylamino group, 3, 4, 5-tri-n-octyloxyphenylcarbonylamino group), carbamoyl group (for example, aminocarbonyl group, methylaminocarbonyl group, dimethylaminocarbonyl group, propylaminocarbonyl group, pentylaminocarbonyl group, cyclohexylaminocarbonyl group, octyl) Aminocarbonyl group, 2-ethylhexylaminocarbonyl group, dodecylaminocarbonyl group, phenylaminocarbonyl group, naphthylaminocarbonyl group, 2-pyridylaminocarbonyl group , Morpholinocarbonyl group, piperazinocarbonyl group, etc.), alkanesulfinyl group or arylsulfinyl group (for example, methanesulfinyl group, ethanesulfinyl group, butanesulfinyl group, cyclohexanesulfinyl group, 2-ethylhexanesulfinyl group, dodecanesulfinyl group) , Phenylsulfinyl group, naphthylsulfinyl group, 2-pyridylsulfinyl group, etc.), alkanesulfonyl group or arylsulfonyl group (for example, methanesulfonyl group, ethanesulfonyl group, butanesulfonyl group, cyclohexanesulfonyl group, 2-ethylhexanesulfonyl group, Dodecanesulfonyl group, phenylsulfonyl group, naphthylsulfonyl group, 2-pyridylsulfonyl group, etc.), amino group (for example, amino group, methylamino group, Tilamino group, dimethylamino group, butylamino group, cyclopentylamino group, 2-ethylhexylamino group, dodecylamino group, anilino group, N-methylanilino group, diphenylamino group, naphthylamino group, 2-pyridylamino group), silyloxy group (Eg, trimethylsilyloxy group, tert-butyldimethylsilyloxy group, etc.), aminocarbonyloxy group (eg, N, N-dimethylcarbamoyloxy group, N, N-diethylcarbamoyloxy group, morpholinocarbonyloxy group, N, N -Di-n-octylaminocarbonyloxy group, Nn-octylcarbamoyloxy group, etc.), alkoxycarbonyloxy group (for example, methoxycarbonyloxy group, ethoxycarbonyloxy group, tert-butoxycarbonyl) Oxy group, n-octylcarbonyloxy group, etc.), aryloxycarbonyloxy group (for example, phenoxycarbonyloxy group, p-methoxyphenoxycarbonyloxy group, pn-hexadecyloxyphenoxycarbonyloxy group, etc.), alkoxycarbonylamino Groups (for example, methoxycarbonylamino group, ethoxycarbonylamino group, tert-butoxycarbonylamino group, n-octadecyloxycarbonylamino group, N-methyl-methoxycarbonylamino group, etc.), aryloxycarbonylamino groups (for example, phenoxycarbonyl) Amino group, p-chlorophenoxycarbonylamino group, mn-octyloxyphenoxycarbonylamino group, etc.), sulfamoylamino group (for example, sulfamoylamino group, N, N -Dimethylaminosulfonylamino group, Nn-octylaminosulfonylamino group, etc.), mercapto group, arylazo group (eg, phenylazo group, naphthylazo group, p-chlorophenylazo group, etc.), heterocyclic azo group (eg, pyridylazo group) , Thiazolylazo group, oxazolylazo group, imidazolylazo group, furylazo group, pyrrolylazo group, 5-ethylthio-1,3,4-thiadiazol-2-ylazo group, etc., imino group (for example, N-succinimido-1-yl group, N-phthalimido-1-yl group, etc.), phosphino group (for example, dimethylphosphino group, diphenylphosphino group, methylphenoxyphosphino group, etc.), phosphinyl group (for example, phosphinyl group, dioctyloxyphosphinyl group, di) Ethoxyphosphinyl group, etc.), phosphine Nyloxy group (for example, diphenoxyphosphinyloxy group, dioctyloxyphosphinyloxy group, etc.), phosphinylamino group (for example, dimethoxyphosphinylamino group, dimethylaminophosphinylamino group, etc.), silyl group (For example, trimethylsilyl group, tert-butyldimethylsilyl group, phenyldimethylsilyl group, etc.), cyano group, nitro group, hydroxyl group, sulfo group, carboxyl group and the like can be mentioned.

  The compound represented by the general formula (M1) may be a multimer such as a dimer or trimer linked by these substituents, or may be a polymer.

  Next, the compound represented by formula (M2) will be described.

In the general formula (M2), Rm ₂₁ , Rm ₂₂ , Rm ₂₃ , and Rm ₂₄ are each independently an aliphatic hydrocarbon group, an aromatic hydrocarbon group, or a heterocyclic ring that may have a hydrogen atom or a substituent. Represents a group. These aliphatic hydrocarbon group, aromatic hydrocarbon group, and heterocyclic group have the same meanings as those in formula (M1).

Z ₁ represents an atomic group necessary for forming a cyclic structure, and preferably forms a 5-membered ring or a 6-membered ring. Z ₁ may further have a substituent, and examples of the substituent include the same substituents as exemplified in the general formula (M1). The atoms constituting Rm _{21 to} Rm ₂₄ and Z ₁ may be linked to each other to form a cyclic structure. For example, together with the nitrogen atom, a polycyclic structure such as an azanorbornene structure or an azaadamantane structure is taken. Also good.

  The ring structure of the compound represented by the general formula (M2) is preferably a piperidine ring, a pyrrolidine ring, or an azaadamantane ring.

  Next, the compound represented by formula (M3) will be described.

  In this invention, it is one of the preferable aspects that the N-oxyl derivative based on this invention is a compound represented by general formula (M3).

In the general formula (M3), Rm ₃₁ is an aliphatic hydrocarbon group or aromatic hydrocarbon which may be substituted directly or substituted with a carbonyl carbon atom via an oxygen atom, a nitrogen atom or a sulfur atom. Rm ₃₂ represents an aliphatic hydrocarbon group, an aromatic hydrocarbon group, or a heterocyclic group which may have a substituent. These aliphatic hydrocarbon group, aromatic hydrocarbon group, and heterocyclic group have the same meanings as those in formula (M1). Rm ₃₁ and Rm ₃₂ may be connected to each other to form a cyclic structure.

In the general formula (M3), Rm ₃₂ is preferably an aromatic hydrocarbon group, particularly preferably a phenyl group which may have a substituent. The substituent on the phenyl group is preferably an electron-withdrawing group such as a cyano group, an alkoxycarbonyl group, or a trifluoromethyl group. Rm ₃₁ is preferably a phenyl group or an aliphatic hydrocarbon group directly bonded to a carbonyl carbon atom, particularly preferably a branched alkyl group or a cycloalkyl group. Note that it is preferable that the compound represented by the general formula (M3) be added in a state of N—OH to manufacture a display element.

  Next, the compound represented by formula (M4) will be described.

  In this invention, it is one of the preferable aspects that the N-oxyl derivative which concerns on this invention is a compound represented by the said general formula (M4).

In the above general formula (M4), Z ₂ represents an atomic group necessary for forming a cyclic structure, and preferably forms a 5-membered ring or a 6-membered ring. Z ₂ may further have a substituent, and examples of the substituent include the substituents exemplified in Formula (M1). Z ₂ may be a condensed ring. Note that the compound represented by the general formula (M4) is preferably added in the state of N—OH to manufacture a display element.

  Next, the compound represented by formula (M5) will be described.

  In this invention, it is one of the preferable aspects that the N-oxyl derivative which concerns on this invention is a compound represented by the said general formula (M5).

In the general formula (M5), Rm _{51 to} Rm ₅₅ each independently represents an aliphatic hydrocarbon group, an aromatic hydrocarbon group, or a heterocyclic group which may have a substituent. These aliphatic hydrocarbon group, aromatic hydrocarbon group, and heterocyclic group have the same meanings as those in formula (M1).

In the general formula (M5), Rm ₅₁ is preferably an aromatic hydrocarbon group, particularly preferably a phenyl group which may have a substituent. The substituent on the phenyl group is preferably an electron-withdrawing group such as a cyano group, an alkoxycarbonyl group, or a trifluoromethyl group. The Rm ₅₂ ~Rm _55, preferably an alkyl group having 1 to 6 carbon atoms, a methyl group is particularly preferred.

  Next, the compound represented by formula (M6) will be described.

In the general formula (M6), Rm ₆₁ and Rm ₆₂ each independently represent a hydrogen atom or an aliphatic hydrocarbon group which may have a substituent. Rm ₆₁ and Rm ₆₂ are preferably a hydrogen atom or a linear alkyl group having 4 or less carbon atoms, and at least one of Rm ₆₁ and Rm ₆₂ is preferably a hydrogen atom.

Z ₃ , Z ₄ and Z ₅ each represent an atomic group necessary for forming a cyclic structure (for example, carbon, nitrogen, oxygen, sulfur, etc.) and each form a 5-membered ring or a 6-membered ring. preferable. Z ₃ , Z ₄ and Z ₅ may further have a substituent.

  n represents 0 or 1, but when n = 0, the general formula (M6) represents a bicyclo compound, and when n = 1, a tricyclo compound.

  As the compound represented by the general formula (M6), n = 1 is preferable, and an azaadamantane derivative is particularly preferable.

  Specific examples of promoters that can be used in the present invention are shown below, but are not limited thereto.

[Compound represented by general formula [I]]
In the present invention, the auxiliary compound that can be electrochemically oxidized / reduced is a counter electrode reactant, and the counter electrode reactant further has a partial structure of a carbon-nitrogen double bond represented by the above general formula [I]. It is preferable that it is a metal complex which uses the compound which has as an organic ligand.

In the general formula [I], R ₃₁ , R ₃₂ , R ₃₃ and R ₃₄ are each independently a hydrogen atom, amino group, hydroxy group, mercapto group, alkoxy group, alkyl group, alkenyl group, alkynyl group or aryl group. Alternatively, it represents a heterocyclic group, and these substituents may further have a substituent. R ₃₁ and R ₃₂ , R ₃₂ and R ₃₃ and R ₃₃ and R ₃₄ may be linked to each other to form an aromatic or non-aromatic cyclic structure, and any position on the cyclic structure May have a substituent.

A compound in which R ₃₁ and R ₃₂ , R ₃₂ and R ₃₃ or R ₃₃ and R ₃₄ are linked to each other to form an aromatic or non-aromatic cyclic structure is preferable.

When R ₃₁ and R ₃₂ are connected to each other to form a cyclic structure, the organic ligand having a carbon-nitrogen double bond as a partial structure according to the present invention is represented by the following general formula [II] Is preferred.

In the general formula [II], R ₃₃ and R ₃₄ have the same meanings as those in the general formula [I], and Z represents an atomic group necessary to form a cyclic structure together with C═N. Further, these cyclic structures may have a substituent at any substitutable position. These ring structures are preferably aromatic heterocyclic structures.

  Specific examples of the cyclic structure skeleton in which substituents are omitted are illustrated below, but are not limited thereto. In addition, in each cyclic structure skeleton shown below, * represents a bonding position.

In the general formula [I], when R ₃₁ and R ₃₂ and R ₃₃ and R ₃₄ are connected to each other to form a cyclic structure, the organic compound having a carbon-nitrogen double bond according to the present invention as a partial structure. The ligand is preferably a compound represented by the following general formula [III].

In the general formula [III], Z ₁ and Z ₂ together with C═N represent an atomic group necessary for forming a cyclic structure. Further, the compound represented by the general formula [III] may have a substituent at any substitutable position on the two cyclic structures. There is no restriction | limiting in particular as this substituent, The substituent shown as a concrete cyclic structure of the said general formula [I] may be sufficient.

In the above general formula [I], when R ₃₂ and R ₃₃ are connected to each other to form a cyclic structure, the organic ligand having a carbon-nitrogen double bond as a partial structure according to the present invention is: A compound represented by the general formula [IV] is preferable.

In the general formula [IV], R ₃₁ and R ₃₄ have the same meanings as those in the general formula [I], and Z ₃ represents an atomic group necessary for forming a cyclic structure together with two carbon atoms. To express. Further, this cyclic structure may have a substituent at any substitutable position.

  Among the general formulas [I] to [IV], a compound represented by the following general formula [V] or general formula [VI] is particularly preferable.

In the general formula [V], R ₃₁ and R ₃₄ have the same meanings as those in the general formula [I]. In the general formula [VI], R ₄₁ and R ₄₂ each represents an alkyl group which may have a substituent.

  The organic ligand having a carbon-nitrogen double bond as a partial structure according to the present invention is a chemically or physically adsorbing trivalent adsorbing group from the electrode from the viewpoint of adhesion to the electrode surface and durability of the film. It is preferable to have at least one.

  The chemical adsorption according to the present invention is a relatively strong adsorption state due to a chemical bond with the electrode surface, and the physical adsorption according to the present invention is a relatively strong van der Waals force acting between the electrode surface and the adsorbed substance. It is weakly adsorbed.

The adsorptive group of the present invention is preferably a chemisorbable group. Examples of the adsorptive group to be chemisorbed include —COOH, —P—O (OH) ₂ , —OP═O (OH) ₂ and -Si (OR) ₃ (R represents an alkyl group).

  Hereinafter, specific examples of the organic ligand having a carbon-nitrogen double bond as a partial structure according to the present invention, and further having an adsorptive group that chemically or physically adsorbs on the electrode surface However, it is not limited to these.

  Next, examples of metal complexes in which at least one organic ligand having a carbon-nitrogen double bond as a partial structure used in the present invention is coordinated are shown, but the invention is not limited thereto. In the table, M represents a central metal, L represents an organic ligand, n represents the number of ligands, and A represents a counter salt for neutralizing the charge.

[Metal salt compounds]
The metal salt compound according to the present invention is any compound as long as it contains a metal species that can be dissolved and precipitated by driving the counter electrode on at least one electrode on the counter electrode. There may be. Preferred metal species are silver, bismuth, copper, nickel, iron, chromium, zinc and the like, and particularly preferred are silver and bismuth.

[Silver salt compound]
The silver salt compound according to the present invention is silver or a compound containing silver in the chemical structure, such as silver oxide, silver sulfide, metallic silver, silver colloidal particles, silver halide, silver complex compound, silver ion and the like. There are no particular restrictions on the phase state species such as the solid state, the solubilized state in liquid, and the gas state, and the charged state species such as neutral, anionic, and cationic.

  In the display element of the present invention, silver iodide, silver chloride, silver bromide, silver oxide, silver sulfide, silver citrate, silver acetate, silver behenate, silver p-toluenesulfonate, silver trifluoromethanesulfonate, mercapto It is preferable to use a known silver salt compound such as a silver salt with an acid or a silver complex with iminodiacetic acid. Among these, it is more preferable to use, as the silver salt, a compound that does not have a nitrogen atom having coordination properties with halogen, carboxylic acid, or silver, and for example, silver p-toluenesulfonate is particularly preferable.

  The metal ion concentration contained in the electrolyte according to the present invention is preferably 0.2 mol / kg ≦ [Metal] ≦ 2.0 mol / kg. If the metal ion concentration is 0.2 mol / kg or more, a silver solution having a sufficient concentration can be obtained, and a desired driving speed can be obtained. If the metal ion concentration is 2 mol / kg or less, precipitation is prevented, and storage at low temperature is possible. The stability of the electrolyte solution is improved.

[Halogen ion, metal ion concentration ratio]
In the display element of the present invention, the molar concentration of halogen ions or halogen atoms contained in the electrolyte layer is [X] (mol / kg), and the molar concentration of metal ions contained in the electrolyte layer is [Metal] ( Mol / kg), it is preferable to satisfy the conditions defined by the following formula (1).

Formula (1)
0 ≦ [X] / [Metal] ≦ 0.01
The halogen atom as used in the field of this invention means an iodine atom, a chlorine atom, a bromine atom, and a fluorine atom. When [X] / [Metal] is larger than 0.01, X ⁻ → X ₂ is generated during the metal redox reaction, and X ₂ easily cross-oxidizes with the deposited metal to dissolve the deposited metal. Therefore, the molar concentration of halogen atoms is preferably as low as possible relative to the molar concentration of metallic silver. In the case of adding halogen ions, the halogen species preferably have a total molar concentration of [I] <[Br] <[Cl] <[F] from the viewpoint of improving memory properties.

[Electrochromic compound]
The electrochromic compound (EC compound) according to the present invention is not particularly limited as long as it exhibits an action of coloring or decoloring by at least one of an electrochemical oxidation reaction and a reduction reaction, and may be appropriately selected according to the purpose. it can. EC compounds include tungsten oxide, iridium oxide, nickel oxide, cobalt oxide, vanadium oxide, molybdenum oxide, titanium oxide, indium oxide, chromium oxide, manganese oxide, Prussian blue, indium nitride, tin nitride, zirconium nitride chloride, etc. In addition to compounds, organometallic complexes, conductive polymer compounds, and organic dyes are known.

  Examples of the organometallic complex exhibiting electrochromic properties include metal-bipyridyl complexes, metal phenanthroline complexes, metal-phthalocyanine complexes, rare earth diphthalocyanine complexes, and ferrocene dyes.

  Examples of the conductive polymer compound exhibiting electrochromic characteristics include polypyrrole, polythiophene, polyisothianaphthene, polyaniline, polyphenylenediamine, polybenzidine, polyaminophenol, polyvinylcarbazole, polycarbazole, and derivatives thereof.

  For example, a polymer material composed of a bisterpyridine derivative and a metal ion as described in JP-A-2007-112957 also exhibits electrochromic properties.

  Examples of organic dyes exhibiting electrochromic properties include pyridinium compounds such as viologen, azine dyes such as phenothiazine, styryl dyes, anthraquinone dyes, pyrazoline dyes, fluorane dyes, donor / acceptor compounds (for example, tetracyanoquino compounds) Dimethane, tetrathiafulvalene) and the like. In addition, compounds known as redox indicators and pH indicators can also be used.

(Classification of EC compounds by color tone)
The EC compounds according to the present invention are classified into the following three classes when classified in terms of color change.

  Class 1: EC compounds that change from one specific color to another by redox.

  Class 2: EC compounds that are substantially colorless in the oxidized state and exhibit a specific colored state that is the reduced state.

  Class 3: EC compounds that are substantially colorless in the reduced state and exhibit a particular colored state that is the oxidized state.

  In the display element of the present invention, the class 1 to class 3 EC compounds can be appropriately selected depending on the purpose and application.

<Class 1 EC compounds>
Class 1 EC compounds are EC compounds that change from a specific color to another color by oxidation-reduction, and are compounds capable of displaying two or more colors in their possible oxidation states.

As a compound classified into class 1, for example, V ₂ O ₅ changes from an orange state to a green color by changing from an oxidation state to a reduction state, and similarly Rh ₂ O ₃ changes from a yellow color to a dark green color.

  Many of the organometallic complexes are classified as class 1, and ruthenium (II) bipyridine complexes, such as tris (5,5'-dicarboxylethyl-2,2'-bipyridine) ruthenium complexes, are between +2 and -4 valences, The color changes from orange to purple, blue, green blue, brown, red rust and red. Many of the rare earth diphthalocyanines also exhibit such multicolor characteristics. For example, in the case of lutetium diphthalocyanine, the color gradually changes from purple to blue, green, and red-orange according to oxidation.

  Many of the conductive polymers are also classified as class 1. For example, polythiophene changes from blue to red by changing from an oxidized state to a reduced state, and polypyrrole changes from brown to yellow. In addition, polyaniline or the like exhibits multicolor characteristics and changes from an amber color in an oxidation state to blue, green, and light yellow in order.

  EC compounds classified as class 1 have a merit that multicolor display is possible with a single compound, but on the other hand, they have a drawback that a state that can be said to be substantially colorless cannot be made.

<Class 2 EC compounds>
Class 2 EC compounds are compounds that are colorless or extremely light in an oxidized state and exhibit a specific colored state that is a reduced state.

Examples of the inorganic compounds classified as class 2 include the following compounds, each of which shows the color shown in parentheses in the reduced state. WO ₃ (blue), MnO ₃ (blue), Nb ₂ O ₅ (blue), TiO ₂ (blue) and the like.

  As an organometallic complex classified into class 2, for example, a tris (vasophenanthroline) iron (II) complex can be mentioned, which shows red in a reduced state.

  Examples of organic dyes classified as class 2 include compounds described in JP-A Nos. 62-71934 and 2006-71765, such as dimethyl terephthalate (red), 4,4'-biphenylcarboxylic acid. Examples thereof include diethyl (yellow), 1,4-diacetylbenzene (cyan), and tetrazolium salt compounds described in JP-A-1-230026, JP-T 2000-504964, and the like.

  The most typical compounds classified as class 2 are pyridinium compounds such as viologen. Viologen compounds have the advantages of vivid display and the ability to have color variations by changing substituents. Therefore, they are the most actively studied among organic dyes. ing. Color development is based on organic radicals generated by reduction.

  Examples of pyridinium-based compounds such as viologen include compounds described in the following patents, starting with JP 2000-506629 A.

  JP-A-5-70455, JP-A-5-170738, JP-A-2000-235198, JP-A-2001-114769, JP-A-2001-172293, JP-A-2001-181292, JP-A-2001-181293, Table 2001-510590, JP-A-2004-101729, JP-A-2006-154683, JP-T-2006-519222, JP-A-2007-31708, 2007-171817, 2007-219271, 2007-219272, JP-T JP 2007-279659, JP 2007-279570, JP 2007-279571, JP 2007-279572, and the like.

  Examples of pyridinium compounds such as viologen that can be used in the present invention are shown below, but are not limited thereto.

<Class 3 EC compounds>
Class 3 EC compounds are compounds that are colorless or extremely pale in the reduced state and exhibit a specific colored state that is an oxidized state.

  Examples of inorganic compounds classified as class 3 include iridium oxide (dark blue), Prussian blue (blue), and the like (each exhibiting the color shown in parentheses in the oxidized state).

  There are few examples of conductive polymers classified into class 3, but examples include phenyl ether compounds described in JP-A-6-263846.

  Many dyes are known as class 3 dyes, but styryl dyes, azine dyes such as phenazine, phenothiazine, phenoxazine, and acridine, azole dyes such as imidazole, oxazole, and thiazole are preferable. .

  Examples of styryl dyes, azine dyes, and azole dyes that can be used in the present invention are shown below, but are not limited thereto.

  In a preferred embodiment of the present invention, a metal salt that reversibly dissolves and precipitates by an electrochemical redox reaction is used in combination with the EC dye, and a multicolor of three or more colors of black display, white display, and non-black color display. Display. In this case, since the metal salt is reduced to give a black display, the EC dye is preferably a class 3 EC compound that develops color by oxidation, and in particular, azoles in terms of color development diversity, low driving voltage, memory properties, and the like. System dyes are preferred.

[Compound represented by formula (L)]
In the present invention, the most preferable dye is a compound represented by the general formula (L).

  Hereinafter, the electrochromic compound represented by the general formula (L) according to the present invention will be described.

In the general formula (L), Rl ₁ represents a substituted or unsubstituted aryl group, and Rl ₂ and Rl ₃ each represent a hydrogen atom or a substituent. X represents> N—Rl ₄ , an oxygen atom or a sulfur atom, and Rl ₄ represents a hydrogen atom or a substituent.

When Rl ₁ represents an aryl group having a substituent, the substituent is not particularly limited, and examples thereof include the following substituents.

  Alkyl groups (eg, methyl, ethyl, propyl, isopropyl, tert-butyl, pentyl, hexyl, etc.), cycloalkyl groups (eg, cyclohexyl, cyclopentyl, etc.), alkenyl groups, cycloalkenyl groups , Alkynyl groups (for example, propargyl group), glycidyl groups, acrylate groups, methacrylate groups, aromatic groups (for example, phenyl group, naphthyl group, anthracenyl group, etc.), heterocyclic groups (for example, pyridyl group, thiazolyl group, oxazolyl group) Group, imidazolyl group, furyl group, pyrrolyl group, pyrazinyl group, pyrimidinyl group, pyridazinyl group, selenazolyl group, sriphoranyl group, piperidinyl group, pyrazolyl group, tetrazolyl group, etc.), alkoxy group (for example, methoxy group, ethoxy group, propyloxy) Group, pliers Oxy group, cyclopentyloxy group, hexyloxy group, cyclohexyloxy group, etc.), aryloxy group (eg, phenoxy group, etc.), alkoxycarbonyl group (eg, methyloxycarbonyl group, ethyloxycarbonyl group, butyloxycarbonyl group, etc.) , Aryloxycarbonyl group (for example, phenyloxycarbonyl group), sulfonamide group (for example, methanesulfonamide group, ethanesulfonamide group, butanesulfonamide group, hexanesulfonamide group, cyclohexanesulfonamide group, benzenesulfonamide group ), Sulfamoyl group (for example, aminosulfonyl group, methylaminosulfonyl group, dimethylaminosulfonyl group, butylaminosulfonyl group, hexylaminosulfonyl group, cyclohexylamino) Sulfonyl group, phenylaminosulfonyl group, 2-pyridylaminosulfonyl group, etc.), urethane group (for example, methylureido group, ethylureido group, pentylureido group, cyclohexylureido group, phenylureido group, 2-pyridylureido group), acyl Groups (eg, acetyl, propionyl, butanoyl, hexanoyl, cyclohexanoyl, benzoyl, pyridinoyl, etc.), carbamoyl groups (eg, aminocarbonyl, methylaminocarbonyl, dimethylaminocarbonyl, propylamino) Carbonyl group, pentylaminocarbonyl group, cyclohexylaminocarbonyl group, phenylaminocarbonyl group, 2-pyridylaminocarbonyl group, etc.), acylamino group (for example, acetylamino group, benzoyla) Mino group, methylureido group etc.), sulfonyl group (eg methylsulfonyl group, ethylsulfonyl group, butylsulfonyl group, cyclohexylsulfonyl group, phenylsulfonyl group, 2-pyridylsulfonyl group etc.), amino group (eg amino group, Ethylamino group, dimethylamino group, butylamino group, cyclopentylamino group, anilino group, 2-pyridylamino group, etc.), halogen atom (eg chlorine atom, bromine atom, iodine atom etc.), cyano group, nitro group, sulfo group Carboxyl group, hydroxyl group, phosphono group (for example, phosphonoethyl group, phosphonopropyl group, phosphonooxyethyl group) and the like. Further, these groups may be further substituted with these groups.

Rl ₁ is preferably a substituted or unsubstituted phenyl group, more preferably a substituted or unsubstituted 2-hydroxyphenyl group or 4-hydroxyphenyl group.

The substituent represented by R1 ₂ or Rl ₃ is not particularly limited, and examples thereof include the substituents exemplified as the substituent on the aryl group of Rl ₁ . Rl ₂ and Rl ₃ are preferably an alkyl group, a cycloalkyl group, an aromatic group, or a heterocyclic group, which may have a substituent. Rl ₂ and Rl ₃ may be linked to each other to form a ring structure. The combination of Rl ₂ and Rl ₃ may be a phenyl group or a heterocyclic group, both of which may have a substituent, or Either one is a phenyl group or a heterocyclic group which may have a substituent, and the other is a combination of an alkyl group which may have a substituent.

X is preferably a> N-Rl _4. Rl ₄ is preferably a hydrogen atom, an alkyl group, an aromatic group, a heterocyclic group or an acyl group, more preferably a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an aryl group having 5 to 10 carbon atoms, or acyl. It is a group.

  In the display element of the present invention, the compound represented by the general formula (L) preferably has an adsorptive group that is chemically or physically adsorbed to the electrode surface. The chemical adsorption referred to in the present invention is a relatively strong adsorption state due to a chemical bond with the electrode surface, and the physical adsorption referred to in the present invention is a relatively strong van der Waals force acting between the electrode surface and the adsorbed substance. It is weakly adsorbed.

In the present invention, the adsorptive group is preferably a chemisorbable group, and as the adsorptive group to be chemisorbed, —COOH, —P═O (OH) ₂ , —OP═O (OH) ₂ and -Si (OR) ₃ (R represents an alkyl group) is preferable.

  Among the azole dyes represented by the general formula (L), an imidazole dye represented by the following general formula (L2) is particularly preferable.

In the general formula (L2), Rl ₂₁ and Rl ₂₂ represent an aliphatic group, an aliphatic oxy group, an acylamino group, a carbamoyl group, an acyl group, a sulfonamide group, and a sulfamoyl group, and R1 ₂₃ represents an aromatic group or an aromatic group. Represents a heterocyclic group, Rl ₂₄ represents a hydrogen atom, an aliphatic group, an aromatic group or an aromatic heterocyclic group, and Rl ₂₅ represents a hydrogen atom, an aliphatic group, an aromatic group or an acyl group.

These groups represented by Rl ₂₁ to Rl ₂₅ may be further substituted with an arbitrary substituent. However, at least one of the groups represented by Rl ₂₁ to Rl ₂₅ has, as its partial structure, —COOH, —P═O (OH) ₂ , —OP═O (OH) ₂ and —Si (OR) ₃ ( R represents an alkyl group.

In the general formula (L2), the group represented by Rl ₂₁ or Rl ₂₂ is preferably an alkyl group (particularly a branched alkyl group), a cycloalkyl group, an alkyloxy group, or a cycloalkyloxy group. Rl ₂₃ is preferably a substituted or unsubstituted phenyl group, a 5-membered or 6-membered heterocyclic group (for example, thienyl group, furyl group, pyrrolyl group, pyridyl group, etc.). Rl ₂₄ is preferably a substituted or unsubstituted phenyl group, a 5-membered or 6-membered heterocyclic group, or an alkyl group. Rl ₂₅ is particularly preferably a hydrogen atom or an aryl group.

In addition, when the compound represented by the general formula (L2) is fixed on the electrode, at least one of the groups represented by Rl _{21 to} Rl ₂₅ includes —P═O (OH) ₂ , —Si as a partial structure. It is preferable to have (OR) ₃ (R represents an alkyl group), and in particular, —Si (OR) ₃ (R represents an alkyl group) as a partial structure of the group represented by Rl ₂₃ or Rl _24. It is preferable to have.

  Specific examples of the EC dye represented by the general formula (L2) and specific examples of the EC dye included in the general formula (L) are shown below, although they do not correspond to the general formula (L2). Is not limited to these exemplified compounds.

[Organic solvent]
Organic solvents are generally used in electrochemical cells and batteries, and include various additives such as electrochromic compounds used in the present invention, metal salt compounds that reversibly dissolve and precipitate by electrochemical redox reactions, promoters, and the like. Any solvent that can be dissolved can be used.

  Specifically, acetic anhydride, methanol, ethanol, tetrahydrofuran, propylene carbonate, nitromethane, acetonitrile, dimethylformamide, dimethyl sulfoxide, hexamethylphosphoamide, ethylene carbonate, dimethoxyethane, γ-butyrolactone, γ-valerolactone, sulfolane, dimethoxy Ethane, propiononitrile, glutaronitrile, adiponitrile, methoxyacetonitrile, dimethylacetamide, methylpyrrolidinone, dimethyl sulfoxide, dioxolane, sulfolane, trimethyl phosphate, triethyl phosphate, tripropyl phosphate, ethyldimethyl phosphate, tributyl phosphate, phosphorus Tripentyl phosphate, trihexyl phosphate, triheptyl phosphate, trioctyl phosphate, trinonyl phosphate, phosphate Ridecyl, tris phosphate (trifluoromethyl), tris phosphate (pentafluoroethyl), triphenyl polyethylene glycol phosphate, polyethylene glycol, and the like can be used. Furthermore, room temperature molten salts can also be used as solvents. The room temperature molten salt is a salt composed of ion pairs that are melted at room temperature (that is, in a liquid state) consisting only of ion pairs that do not contain a solvent component, and usually has a melting point of 20 ° C. or lower, and 20 ° C. The salt which consists of an ion pair which is liquid at the temperature over is shown. The room temperature molten salt can be used alone or in combination of two or more.

  The electrolyte solvent used in the present invention is preferably an aprotic polar solvent, particularly propylene carbonate, ethylene carbonate, dimethyl sulfoxide, dimethoxyethane, acetonitrile, γ-butyrolactone, sulfolane, dioxolane, dimethylformamide, dimethoxyethane, tetrahydrofuran, adiponitrile, Methoxyacetonitrile, dimethylacetamide, methylpyrrolidinone, dimethyl sulfoxide, dioxolane, sulfolane, trimethyl phosphate, and triethyl phosphate are preferred. The solvent may be used alone or in combination of two or more.

[White scattered matter]
In the present invention, from the viewpoint of further increasing the display contrast and the white display reflectance, it is preferable to contain a white scattering material, and a porous white scattering layer may be formed and present.

  The porous white scattering layer applicable to the present invention can be formed by applying and drying an aqueous mixture of an aqueous polymer and a white pigment that is substantially insoluble in the electrolyte solvent.

  In the present invention, “substantially insoluble in an electrolyte solvent” is defined as a state in which the dissolved amount per kg of electrolyte solvent is 0 g or more and 10 g or less at a temperature of −20 ° C. to 120 ° C. The amount of dissolution can be determined by a known method such as a component determination method using a chromatogram or a gas chromatogram.

  In the present invention, examples of the water-based polymer that does not substantially dissolve in the electrolyte solvent include a water-soluble polymer and a polymer dispersed in the water-based solvent.

Examples of water-soluble compounds include proteins such as gelatin and gelatin derivatives, or cellulose derivatives, natural compounds such as starch, gum arabic, dextran, pullulan, and carrageenan polysaccharides, polyvinyl alcohol, polyethylene glycol, polyvinyl pyrrolidone, and acrylamide polymers. And synthetic polymer compounds such as derivatives thereof. As gelatin derivatives, acetylated gelatin, phthalated gelatin, polyvinyl alcohol derivatives as terminal alkyl group-modified polyvinyl alcohol, terminal mercapto group-modified polyvinyl alcohol, and cellulose derivatives include hydroxyethyl cellulose, hydroxypropyl cellulose, carboxymethyl cellulose and the like. It is done. Furthermore, Research Disclosure and those described in pages (71) to (75) of JP-A No. 64-13546, US Pat. No. 4,960,681, JP-A No. 62-245260, etc. superabsorbent polymers described, namely -COOM or -SO 3 M _(M is a hydrogen atom or an alkali metal) homopolymer or a vinyl monomer together or with other vinyl monomers of the vinyl monomer having a (e.g., sodium methacrylate, Copolymers with ammonium acid, potassium acrylate, etc.) are also used. These binders can be used in combination of two or more.

  In the present invention, polyvinyl alcohol, polyethylene glycol, and polyvinylpyrrolidone compounds can be preferably used.

  Polymers dispersed in water-based solvents include natural rubber latex, styrene butadiene rubber, butadiene rubber, nitrile rubber, chloroprene rubber, isoprene rubber and other latexes, polyisocyanate, epoxy, acrylic, silicon, polyurethane, Examples thereof include a thermosetting resin in which urea, phenol, formaldehyde, epoxy-polyamide, melamine, alkyd resin, vinyl resin and the like are dispersed in an aqueous solvent. Of these polymers, it is preferable to use an aqueous polyurethane resin described in JP-A-10-76621.

  The average molecular weight of the water-based polymer of the present invention is preferably in the range of 10,000 to 2,000,000, more preferably in the range of 30,000 to 500,000 on a weight average basis.

  Examples of the white pigment applicable in the present invention include titanium dioxide (anatase type or rutile type), barium sulfate, calcium carbonate, aluminum oxide, zinc oxide, magnesium oxide and zinc hydroxide, magnesium hydroxide, magnesium phosphate, Magnesium hydrogen phosphate, alkaline earth metal salt, talc, kaolin, zeolite, acidic clay, glass, organic compounds such as polyethylene, polystyrene, acrylic resin, ionomer, ethylene-vinyl acetate copolymer resin, benzoguanamine resin, urea-formalin resin, A melamine-formalin resin, a polyamide resin, or the like may be used alone or in combination, or in a state having voids that change the refractive index in the particles.

In the present invention, among the white particles, titanium dioxide is preferably used. In particular, titanium dioxide surface-treated with an inorganic oxide (Al ₂ O ₃ , AlO (OH), SiO _2, etc.), in addition to these surface treatments. Titanium dioxide that has been treated with an organic substance such as trimethylolethane, triethanolamine acetate, or trimethylcyclosilane is more preferably used.

  Of these white particles, it is more preferable to use titanium oxide or zinc oxide from the viewpoint of coloring prevention at high temperature and the reflectance of the element due to the refractive index.

  In the present invention, the water mixture of the water-based compound and the white pigment is preferably in a form in which the white pigment is dispersed in water according to a known dispersion method. The mixing ratio of the aqueous compound / white pigment is preferably 1 to 0.01, more preferably 0.3 to 0.05 in terms of volume ratio.

  The thickness of the porous white scattering layer is preferably in the range of 5 to 50 μm, more preferably in the range of 10 to 30 μm.

  As the alcohol solvent, a compound having high solubility in water such as methanol, ethanol, isopropanol is preferably used, and the mixing ratio with the water / alcohol solvent is preferably in the range of 0.5 to 20 by mass ratio, More preferably, it is the range of 2-10.

  In the present invention, the medium for applying the water mixture of the water-based compound and the white pigment may be at any position as long as it is on the component between the counter electrodes of the display element, but on the electrode surface of at least one of the counter electrodes. It is preferable to give to.

  As a method for applying to a medium, for example, a coating method, a liquid spraying method, a spraying method via a gas phase, a method of flying droplets using vibration of a piezoelectric element, for example, a piezoelectric inkjet head, Examples thereof include a bubble jet (registered trademark) type ink jet head that causes droplets to fly using a thermal head that uses bumping, and a spray type that sprays liquid by air pressure or liquid pressure.

  As a coating method, it can select suitably from a well-known coating method. For example, air doctor coater, blade coater, rod coater, knife coater, squeeze coater, impregnation coater, reverse roller coater, transfer roller coater, curtain coater, double roller coater, slide hopper coater, gravure coater, kiss roll coater, bead coater, Examples include cast coaters, spray coaters, calendar coaters, and extrusion coaters.

  Drying of the water mixture of the aqueous compound and the white pigment applied on the medium may be performed by any method as long as water can be evaporated. For example, heating from a heat source, a heating method using infrared light, a heating method using electromagnetic induction, and the like can be given. Further, water evaporation may be performed under reduced pressure.

  Porous as used in the present invention refers to the formation of a porous white scattering material by applying a water admixture of the water-based compound and the white pigment onto the electrode and drying it, and then the silver or silver is chemically treated on the scattering material. After supplying an electrolyte solution containing the compound contained in the structure, it can be sandwiched between opposing electrodes, giving a potential difference between the opposing electrodes, causing a silver dissolution precipitation reaction, and penetrating ions that can move between the electrodes Tell the state.

  In the display element of the present invention, it is desirable to carry out a curing reaction of the water-based compound with a curing agent during or after applying and drying the water mixture described above.

  Examples of the hardener used in the present invention include, for example, U.S. Pat. No. 4,678,739, column 41, 4,791,042, JP-A-59-116655, and 62-245261. No. 61-18942, 61-249054, 61-245153, JP-A-4-218044, and the like. More specifically, aldehyde hardeners (formaldehyde, etc.), aziridine hardeners, epoxy hardeners, vinyl sulfone hardeners (N, N'-ethylene-bis (vinylsulfonylacetamide) Ethane, etc.), N-methylol hardeners (dimethylolurea, etc.), boric acid, metaboric acid or polymer hardeners (compounds described in JP-A-62-234157). When gelatin is used as the aqueous compound, it is preferable to use a vinyl sulfone type hardener or a chlorotriazine type hardener alone or in combination. Moreover, when using polyvinyl alcohol, it is preferable to use boron-containing compounds such as boric acid and metaboric acid.

  These hardeners are used in an amount of 0.001 to 1 g, preferably 0.005 to 0.5 g, per 1 g of the aqueous compound. In addition, it is possible to perform heat treatment and humidity adjustment during the curing reaction in order to increase the film strength.

〔Electrolytes〕
As the supporting electrolyte that can be used in the display element of the present invention, salts, acids, and alkalis that are usually used in the field of electrochemistry or the field of batteries can be used.

  There are no particular limitations on the salts, and for example, inorganic ion salts such as alkali metal salts and alkaline earth metal salts; quaternary ammonium salts; cyclic quaternary ammonium salts; quaternary phosphonium salts and the like can be used.

Specific examples of the salts include halogen ions, SCN ⁻ , ClO ₄ ⁻ , BF ₄ ⁻ , CF ₃ SO ₃ ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ , (C ₂ F ₅ SO ₂ ) ₂ N ⁻ , PF _{^{6 -, AsF 6 -, CH}} 3 COO -, CH 3 (C 6 H 4) SO 3 -, and _{(C 2 F 5 SO 2)} 3 C - Li salt having a counter anion selected from, Na salt or K salt is mentioned.

Further, halogen ions, SCN ⁻ , ClO ₄ ⁻ , BF ₄ ⁻ , CF ₃ SO ₃ ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ , (C ₂ F ₅ SO ₂ ) ₂ N ⁻ , PF ₆ ⁻ , AsF _{6 ^{-, CH 3 COO -, CH}} 3 (C 6 H 4) SO 3 -, and _{(C 2 F 5 SO 2)} 3 C - 4 quaternary ammonium salt having a counter anion selected from, specifically, (CH ₃ ) ₄ NBF ₄ , (C ₂ H ₅ ) ₄ NBF ₄ , (n-C ₄ H ₉ ) ₄ NBF ₄ , (C ₂ H ₅ ) ₄ NBr, (C ₂ H ₅ ) ₄ NClO ₄ , (n- C ₄ H ₉ ) ₄ NClO ₄ , CH ₃ (C ₂ H ₅ ) ₃ NBF ₄ , (CH ₃ ) ₂ (C ₂ H ₅ ) ₂ NBF ₄ , (CH ₃ ) ₄ NSO ₃ CF ₃ , (C ₂ H _{5) 4 NSO 3 CF 3,} (n-C 4 H 9 ₄ NSO ₃ CF _3,
Furthermore,

Etc.

Further, halogen ions, SCN ⁻ , ClO ₄ ⁻ , BF ₄ ⁻ , CF ₃ SO ₃ ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ , (C ₂ F ₅ SO ₂ ) ₂ N ⁻ , PF ₆ ⁻ , AsF _{6 ^{-, CH 3 COO -, CH}} 3 (C 6 H 4) SO 3 -, and _{(C 2 F 5 SO 2)} 3 C - phosphonium salt having a counter anion selected from, specifically, _(CH 3) ₄ PBF ₄ , (C ₂ H ₅ ) ₄ PBF ₄ , (C ₃ H ₇ ) ₄ PBF ₄ , (C ₄ H ₉ ) ₄ PBF _{4 and the} like. Moreover, these mixtures can also be used suitably.

The supporting electrolyte of the present invention is preferably a quaternary ammonium salt, particularly preferably a quaternary spiro ammonium salt. The _ClO ⁴ as counter anion ^{_{-, BF 4 -, CF 3}} SO 3 -, (C 2 F 5 SO 2) 2 N -, PF 6 - are preferable, and BF ₄ ^- is preferable.

  The amount of the electrolyte salt used is arbitrary, but in general, the electrolyte salt is present in the solvent as an upper limit of 20 mol / L or less, preferably 10 mol / L or less, more preferably 5 mol / L or less. The lower limit is usually 0.01 mol / L or more, preferably 0.05 mol / L or more, more preferably 0.1 mol / L or more.

  In the case of a solid electrolyte, the following compounds exhibiting electronic conductivity and ionic conductivity can be contained in the electrolyte.

Vinyl fluoride polymer containing perfluorosulfonic acid, polythiophene, polyaniline, polypyrrole, triphenylamines, polyvinylcarbazoles, polymethylphenylsilanes, Cu ₂ S, Ag ₂ S, Cu ₂ Se, AgCrSe _2, etc. Fluorine-containing compounds such as chalcogenide, CaF ₂ , PbF ₂ , SrF ₂ , LaF ₃ , TlSn ₂ F ₅ , CeF ₃ , Li salts such as Li ₂ SO ₄ , Li ₄ SiO ₄ , Li ₃ PO ₄ , ZrO ₂ , CaO , Cd ₂ O ₃ , HfO ₂ , Y ₂ O ₃ , Nb ₂ O ₅ , WO ₃ , Bi ₂ O ₃ , AgBr, AgI, CuCl, CuBr, CuBr, CuI, LiI, LiBr, LiCl, LiAlCl ₄ , LiAlF _{4 , AgSBr, C 5 H 5 NHAg} 5 I 6, Rb 4 Cu 16 _{7 Cl 13, Rb 3 Cu 7} Cl 10, LiN, compounds such as _{Li 5 NI 2, Li 6 NBr} 3 , and the like.

[Compounds Represented by General Formulas (G-1) and (G-2)]
In this invention, in order to accelerate | stimulate melt | dissolution precipitation of metal salt (especially silver salt), it is preferable to contain the compound represented by the following general formula (G-1) or general formula (G-2).

(Compound represented by General Formula (G-1) or General Formula (G-2))
In the display element of this invention, it is preferable that electrolyte contains at least 1 sort (s) of the compound represented by the following general formula (G-1) or general formula (G-2). The compounds represented by the general formulas (G-1) and (G-2) are compounds that promote the solubilization of silver in the electrolyte in order to cause dissolution and precipitation of silver in the present invention.

  In general, in order to cause dissolution and precipitation of silver, it is necessary to solubilize silver in the electrolyte. For example, silver that causes a coordinate bond with silver and a weak covalent bond with silver. A compound containing a chemical structural species that interacts with is useful. As the chemical structural species, halogen atoms, mercapto groups, carboxyl groups, imino groups and the like are known, but in the present invention, compounds containing thioether groups and mercaptoazoles are useful as silver solvents and It has a feature that it has little influence on coexisting compounds and high solubility in a solvent.

In the general formula (G-1), Rg ₁₁ and Rg ₁₂ each represent a substituted or unsubstituted hydrocarbon group. These hydrocarbon groups may contain one or more nitrogen atoms, oxygen atoms, phosphorus atoms, sulfur atoms, and halogen atoms, and Rg ₁₁ and Rg ₁₂ may be linked to each other to form a cyclic structure.

In the general formula (G-2), M represents a hydrogen atom, a metal atom, or quaternary ammonium. Z represents an atomic group necessary for constituting a nitrogen-containing heterocyclic ring. n represents an integer of 0 to 5, Rg ₂₁ represents a substituent, and when n is 2 or more, each Rg ₂₁ may be the same or different, and may be connected to each other to form a condensed ring. It may be formed.

In the general formula (G-1), Rg ₁₁ and Rg ₁₂ each represent a substituted or unsubstituted hydrocarbon group. In these hydrocarbon groups, one or more nitrogen atoms, oxygen atoms, phosphorus atoms, sulfur An atom may be included, and Rg ₁₁ and Rg ₁₂ may be connected to each other to take a cyclic structure.

  Examples of groups that can be substituted for the hydrocarbon group include amino groups, guanidino groups, quaternary ammonium groups, hydroxyl groups, halogen compounds, carboxylic acid groups, carboxylate groups, amide groups, sulfinic acid groups, sulfonic acid groups, and sulfates. Groups, phosphonic acid groups, phosphate groups, nitro groups, cyano groups and the like.

  Specific examples of the compound represented by General Formula (G-1) that can be applied in the present invention are shown below, but the present invention is not limited to these exemplified compounds.

G1-1: CH ₃ SCH ₂ CH ₂ OH
G1-2: HOCH ₂ CH ₂ SCH ₂ CH ₂ OH
G1-3: HOCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ OH
G1-4: HOCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ OH
G1-5: HOCH ₂ CH ₂ SCH ₂ CH ₂ OCH ₂ CH ₂ OCH ₂ CH ₂ SCH ₂ CH ₂ OH
_{G1-6: HOCH 2 CH 2 OCH 2} CH 2 SCH 2 CH 2 SCH 2 CH 2 OCH 2 CH 2 OH
G1-7: H ₃ CSCH ₂ CH ₂ COOH
G1-8: HOOCCH ₂ SCH ₂ COOH
G1-9: HOOCCH ₂ CH ₂ SCH ₂ CH ₂ COOH
G1-10: HOOCCH ₂ SCH ₂ CH ₂ SCH ₂ COOH
G1-11: HOOCCH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ COOH
G1-12: HOOCCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH (OH) CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ COOH
G1-13: HOOCCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH (OH) CH (OH) CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ COOH
G1-14: H ₃ CSCH ₂ CH ₂ CH ₂ NH ₂
G1-15: H ₂ NCH ₂ CH ₂ SCH ₂ CH ₂ NH ₂
G1-16: H ₂ NCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ NH ₂
G1-17: H ₃ CSCH ₂ CH ₂ CH (NH ₂ ) COOH
G1-18: H ₂ NCH ₂ CH ₂ OCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ OCH ₂ CH ₂ NH _{2
G1-19: H 2 NCH 2 CH 2} SCH 2 CH 2 OCH 2 CH 2 OCH 2 CH 2 SCH 2 CH 2 NH 2
G1-20: H ₂ NCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ NH ₂
G1-21: HOOC (NH ₂ ) CHCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ CH (NH ₂ ) COOH
G1-22: HOOC (NH ₂ ) CHCH ₂ SCH ₂ CH ₂ OCH ₂ CH ₂ OCH ₂ CH ₂ SCH ₂ CH (NH ₂ ) COOH
G1-23: HOOC (NH ₂ ) CHCH ₂ OCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ OCH ₂ CH (NH ₂ ) COOH
_{G1-24: H 2 N (O =} ) CCH 2 SCH 2 CH 2 OCH 2 CH 2 OCH 2 CH 2 SCH 2 C (= O) NH 2
_{G1-25: H 2 N (O =} ) CCH 2 SCH 2 CH 2 SCH 2 C (= O) NH 2
_{G1-26: H 2 NHN (O =} ) CCH 2 SCH 2 CH 2 SCH 2 C (= O) NHNH 2
_{G1-27: H 3 C (O =} ) NHCH 2 CH 2 SCH 2 CH 2 SCH 2 CH 2 NHC (= O) CH 3
_{G1-28: H 2 NO 2 SCH 2} CH 2 SCH 2 CH 2 SCH 2 CH 2 SO 2 NH 2
_{G1-29: NaO 3 SCH 2 CH 2} CH 2 SCH 2 CH 2 SCH 2 CH 2 CH 2 SO 3 Na
G1-30: H ₃ CSO ₂ NHCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ NHO ₂ SCH ₃
G1-31: H ₂ N (NH) CSCH ₂ CH ₂ SC (NH) NH ₂ .2HBr
_{G1-32: H 2 (NH) CSCH} 2 CH 2 OCH 2 CH 2 OCH 2 CH 2 SC (NH) NH 2 · 2HCl
G1-33: H ₂ N (NH) CNHCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ NHC (NH) NH ₂ .2HBr
G1-34: [(CH ₃ ) ₃ NCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ N (CH ₃ ) ₃ ] 2 ⁺ · 2Cl ⁻

  Of the above-exemplified compounds, Exemplified Compounds G1-2 and G1-3 are particularly preferable from the viewpoint that the object and effects of the present invention can be exhibited.

  Next, the compound represented by formula (G-2) according to the present invention will be described.

In the general formula (G-2), M represents a hydrogen atom, a metal atom, or quaternary ammonium. Z represents an atomic group necessary for constituting a nitrogen-containing heterocyclic ring. n represents an integer of 0 to 5, Rg ₂₁ represents a substituent, and when n is 2 or more, each Rg ₂₁ may be the same or different, and may be connected to each other to form a condensed ring. It may be formed.

In the general formula (G-2), examples of the metal atom represented by M include Li, Na, K, Mg, Ca, Zn, and Ag. Examples of the quaternary ammonium include NH ₄ , N (CH ₃ ) ₄ , N (C ₄ H ₉ ) ₄ , N (CH ₃ ) ₃ C ₁₂ H ₂₅ , N (CH ₃ ) ₃ C ₁₆ H ₃₃ , N (CH ₃ ) ₃ CH ₂ C ₆ H ₅ Etc.

  Examples of the nitrogen-containing heterocycle having Z as a constituent of general formula (G-2) include, for example, a tetrazole ring, a triazole ring, an imidazole ring, an oxadiazole ring, a thiadiazole ring, an indole ring, an oxazole ring, a benzoxazole ring, Examples include a benzimidazole ring, a benzothiazole ring, a benzoselenazole ring, and a naphthoxazole ring.

In the general formula (G-2), the substituent represented by Rg ₂₁ is not particularly limited, and examples thereof include the following substituents.

  Halogen atom (eg, fluorine atom, chlorine atom, bromine atom, iodine atom) Alkyl group (eg, methyl, ethyl, propyl, i-propyl, butyl, t-butyl, pentyl, cyclopentyl, hexyl, cyclohexyl, octyl, dodecyl) , Hydroxyethyl, methoxyethyl, trifluoromethyl, benzyl, etc.), aryl groups (eg, phenyl, naphthyl, etc.), alkylcarbonamide groups (eg, acetylamino, propionylamino, butyroylamino, etc.), arylcarbonamide groups ( For example, benzoylamino etc.), alkylsulfonamide groups (eg methanesulfonylamino group, ethanesulfonylamino group etc.), arylsulfonamide groups (eg benzenesulfonylamino group, toluenesulfonylamino group etc.), Alkyloxy group (eg, phenoxy), alkylthio group (eg, methylthio, ethylthio, butylthio, etc.), arylthio group (eg, phenylthio group, tolylthio group, etc.), alkylcarbamoyl group (eg, methylcarbamoyl, dimethylcarbamoyl, ethylcarbamoyl, diethyl) Carbamoyl, dibutylcarbamoyl, piperidylcarbamoyl, morpholylcarbamoyl, etc.), arylcarbamoyl groups (eg, phenylcarbamoyl, methylphenylcarbamoyl, ethylphenylcarbamoyl, benzylphenylcarbamoyl, etc.), alkylsulfamoyl groups (eg, methylsulfamoyl, Dimethylsulfamoyl, ethylsulfamoyl, diethylsulfamoyl, dibutylsulfamoyl, piperidylsulfamoy , Morpholylsulfamoyl, etc.), arylsulfamoyl groups (eg, phenylsulfamoyl, methylphenylsulfamoyl, ethylphenylsulfamoyl, benzylphenylsulfamoyl, etc.), alkylsulfonyl groups (eg, methanesulfonyl) Group, ethanesulfonyl group, etc.), arylsulfonyl group (for example, phenylsulfonyl, 4-chlorophenylsulfonyl, p-toluenesulfonyl, etc.) alkoxycarbonyl group (for example, methoxycarbonyl, ethoxycarbonyl, butoxycarbonyl, etc.), aryloxycarbonyl group ( For example, phenoxycarbonyl etc.), alkylcarbonyl groups (eg acetyl, propionyl, butyroyl etc.), arylcarbonyl groups (eg benzoyl group, alkylbenzoyl groups etc.), acyl Ruoxy group (for example, acetyloxy, propionyloxy, butyroyloxy, etc.), heterocyclic group (for example, oxazole ring, thiazole ring, triazole ring, selenazole ring, tetrazole ring, oxadiazole ring, thiadiazole ring, thiazine ring, triazine ring, Benzoxazole ring, benzthiazole ring, indolenine ring, benzselenazole ring, naphthothiazole ring, triazaindolizine ring, diazaindolizine ring, tetraazaindolizine ring group). These substituents further include those having a substituent.

  Next, although the preferable specific example of a compound represented by general formula (G-2) is shown, this invention is not limited to these compounds.

  Among the above-exemplified compounds, Exemplified Compounds G2-12 and G2-18 are particularly preferable from the viewpoint that the object and effects of the present invention can be exhibited.

[Electrolyte solvent]
In the display element of the present invention, the electrolyte preferably contains a compound represented by the following general formula (S1) or (S2).

In the general formula (S1), L represents an oxygen atom or an alkylene group, and Rs _{11 to} Rs ₁₄ each represent a hydrogen atom, an alkyl group, an alkenyl group, an aryl group, a cycloalkyl group, an alkoxyalkyl group, or an alkoxy group.

In the general formula (S2), Rs ₂₁ and Rs ₂₂ each represents an alkyl group, an alkenyl group, an aryl group, a cycloalkyl group, an alkoxyalkyl group, or an alkoxy group.

  First, the detail of the compound represented by general formula (S1) is demonstrated.

In the general formula (S1), L represents an oxygen atom or an alkylene group, and Rs _{11 to} Rs ₁₄ each represents a hydrogen atom, an alkyl group, an alkenyl group, an aryl group, a cycloalkyl group, an alkoxyalkyl group, or an alkoxy group, These substituents may be further substituted with an arbitrary substituent.

  Examples of alkyl groups include methyl, ethyl, propyl, isopropyl, tert-butyl, pentyl, hexyl, octyl, dodecyl, tridecyl, tetradecyl, pentadecyl, and the like as aryl groups. Examples of the cycloalkyl group such as phenyl group, naphthyl group and the like include, for example, a cyclopentyl group, cyclohexyl group and the like, an alkoxyalkyl group, for example, a β-methoxyethyl group, a γ-methoxypropyl group and the like, as an alkoxy group, Examples thereof include a methoxy group, an ethoxy group, a propyloxy group, a pentyloxy group, a hexyloxy group, an octyloxy group, and a dodecyloxy group.

  Hereinafter, although the specific example of a compound represented by general formula (S1) is shown, in this invention, it is not limited only to these illustrated compounds.

  Subsequently, the detail of the compound represented by general formula (S2) is demonstrated.

In the general formula (S2), Rs ₂₁ and Rs ₂₂ each represents an alkyl group, an alkenyl group, an aryl group, a cycloalkyl group, an alkoxyalkyl group, or an alkoxy group.

  Examples of alkyl groups include methyl, ethyl, propyl, isopropyl, tert-butyl, pentyl, hexyl, octyl, dodecyl, tridecyl, tetradecyl, pentadecyl, and the like as aryl groups. Examples of the cycloalkyl group such as phenyl group, naphthyl group and the like include, for example, a cyclopentyl group, cyclohexyl group and the like, an alkoxyalkyl group, for example, a β-methoxyethyl group, a γ-methoxypropyl group and the like, as an alkoxy group, Examples thereof include a methoxy group, an ethoxy group, a propyloxy group, a pentyloxy group, a hexyloxy group, an octyloxy group, and a dodecyloxy group.

  Hereinafter, although the specific example of a compound represented by general formula (S2) is shown, in this invention, it is not limited only to these illustrated compounds.

  Among the compounds represented by the general formula (S1) and the general formula (S2) exemplified above, the exemplary compounds S1-1, S1-2, and S2-3 are particularly preferable.

  In the present invention, the electrolyte solvent may be a single type or a mixture of solvents, but a mixed solvent containing ethylene carbonate is preferred. The addition amount of ethylene carbonate is preferably 10% by mass or more and 90% by mass or less of the total electrolyte solvent mass. A particularly preferable electrolyte solvent is a mixed solvent having a mass ratio of propylene carbonate / ethylene carbonate of 7/3 to 3/7. When the propylene carbonate ratio is larger than 7/3, the ionic conductivity is inferior and the response speed is lowered. When the propylene carbonate ratio is smaller than 3/7, the electrolyte tends to be deposited at a low temperature.

  In the present invention, the compound represented by the general formula (1) and the general formula (2) is included in the electrolyte, and is represented by the general formula (1) and the general formula (2) according to the present invention. The resulting compound functions as a gelling agent in the electrolyte solvent. This is because the compounds represented by the general formula (1) and the general formula (2) according to the present invention form a three-dimensionally entangled fibrous network structure with a π-π interaction as a driving force, It is considered that an organic gel is formed by forming a structure in which an electrolyte solvent is included in these voids. In addition, with a conventional gelling agent using a hydrogen bond as a driving force, it is difficult to efficiently gel a polar organic solvent or a hydrogen bonding (protic) organic solvent, but the general formula (1 ) And the compound represented by the general formula (2) use a π-π interaction instead of a hydrogen bond as a driving force, and thus can be gelled in all kinds of solvents.

[Ionic liquid]
An ionic liquid can be applied to the display element of the present invention. The ionic liquid referred to in the present invention is also called a room temperature molten salt, and is a salt having a melting point of 100 ° C. or lower. This salt is composed of the same number of cations and anions, and there are many substances having a melting point below room temperature depending on the molecular structure, and these are in a liquid state at room temperature without adding any solvent. An ionic liquid has a strong characteristic that it has a strong electrostatic interaction and thus has almost no vapor pressure, and does not evaporate even at high temperatures.

  The ionic liquid used in the present invention may be any substance that is generally studied and reported. In particular, an organic ionic liquid has a molecular structure that exhibits a liquid in a wide temperature range including room temperature.

The ionic liquid that can be suitably used in the present invention is represented by the formula Q ⁺ A ⁻ and is 20 to 100 ° C., preferably 20 to 80 ° C., more preferably 20 to 60 ° C., and still more preferably 20 to 40 ° C. In particular, it refers to a salt that exists as a liquid at 20 ° C., and the viscosity (25 ° C.) is not particularly limited as long as it is a melt at normal temperature, but it is preferably 1 to 200 mPa · s. Further, the cation component represented by Q + in the formula is preferably an onium cation, and more preferably an ammonium cation, an imidazolium cation, a pyridinium cation, a sulfonium cation, and a phosphonium cation.

The above ionic liquid will be specifically described in detail. As Q ⁺ in the above formula, R ₁ R ₂ R ₃ R ₄ N ⁺ , R ₁ R ₂ R ₃ S ⁺ , R ₁ R ₂ R ₃ R ₄ P ⁺ , R ₁ R ₂ N ⁺ = CR ₃ R ₄ , R ₁ R ₂ P ⁺ = CR ₃ R ₄ [where R ₁ to R ₄ are, independently of one another, hydrogen, saturated or unsaturated carbon C 1 -C 12 alkyl group, a cycloalkyl group having 3 to 8 carbon atoms, an aryl group or an aralkyl group having a carbon number of 7-11 having 6 to 10 carbon _{atoms, R 5 -X- (R 6 -Y-} ) n - (Wherein R ₅ represents an alkyl group having 4 or less carbon atoms, R ₆ represents an alkylene group having 4 or less carbon atoms, X and Y represent an oxygen atom or a sulfur atom, and n represents an integer of 0 to 10). And the group may be substituted] ammonium selected from the group consisting of Phosphonium _{^{ion, R 1 R 2 N + =}} CR 3 -R 7 -R 3 C = N + R 1 R 2, R 1 R 2 S + -R 7 -S + R 1 R 2, R 1 R 2 P + ^{_{= CR 3 -R 7 -R 3 C}} = P + R 1 R 2 ( _wherein, R 1, _{R 2} and _{R 3} are the same as defined above, and _{R 7} is 1 to carbon atoms A quaternary ammonium and / or phosphonium ion selected from the group consisting of 6 alkylene or phenylene groups, which may have a substituent, and nitrogen represented by the following general formula: Examples thereof include nitrogen ions containing 1, 2 or 3 atoms selected from sulfur and phosphorus atoms, ammonium ions derived from sulfur and phosphorus atom-containing heterocycles, sulfonium ions, phosphonium ions, and the like.

Wherein R ₁ and R ₂ are as defined above, and Z is an atom capable of constituting a 4-10 membered ring containing N ⁺ , N ⁺ = C, S ⁺ , P ⁺ or P ⁺ = C And the constituent atoms may have a substituent.

Specific examples of R ₁ to R _{4 in} the above are methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, octyl, A linear or branched alkyl group such as nonyl and decyl; a cycloalkyl group such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl and cyclooctyl; unsubstituted or halogen atoms (eg, F, Cl, Br, I ), Hydroxyl group, lower alkoxy group (eg, methoxy, ethoxy, propoxy, butoxy, etc.), carboxyl group, acetyl group, propanoyl group, thiol group, lower alkylthio group (eg, methylthio, ethylthio, propylthio, butylthio, etc.) Each group), amino group, lower alkyl Amino group include phenyl having one to three substituents, such as di-lower alkyl amino group, naphthyl, tolyl, aryl group xylyl, and the like aralkyl groups such as benzyl. Further, specific examples of _{R 5} include methyl, ethyl, n- propyl, isopropyl, n- butyl, isobutyl, sec- butyl, and alkyl group such as tert- butyl group, methylene as _{R 6} And alkylene groups such as ethylene, propylene and butylene groups. Furthermore, specific examples of R ₇ include alkylene groups such as methylene, ethylene, propylene, and butylene, and phenylene groups such as phenylene.

Further, A in the formula ^- Examples of the counter anion represented by, hexafluorophosphate, hexafluoroantimonate, hexafluoroarsenate, fluorosulfonate salts, tetrafluoroborate, nitrate, alkyl sulfonate Represents a fluorinated alkyl sulfonate or a hydrogen sulfate.

  Furthermore, WO95 / 18456, JP-A-8-259543, JP-A-2001-243959, Electrochemistry 65, 11, 923 (1997), EP-716288, J. Org. Electrochem. Soc. , Vol. 143, no. 10, 3099 (1996), Inorg. Chem. The pyridinium salts, imidazolium salts, triazolium salts and the like described in 1996, 35, 1168 to 1178 can be selected and used in a timely manner according to the present invention.

[Solid electrolyte, gel electrolyte]
The electrolyte according to the present invention is not only a solution electrolyte composed of a solvent or an ionic liquid, but also a high-viscosity electrolyte or a gel electrolyte (hereinafter, referred to as a solid electrolyte or a polymer compound containing substantially no solvent). Gel electrolyte) can be used.

  Examples of the solid electrolyte and gel electrolyte applicable to the present invention include a solid electrolyte described in JP-A No. 2002-341387, a polymer solid electrolyte described in JP-A No. 2002-341387, and JP-A No. 2004-20928. A solid polymer electrolyte described in JP-A No. 2004-191945, a solid polymer electrolyte described in JP-A No. 2005-338204, and a polymer described in JP-A No. 2006-323022 Examples thereof include solid electrolytes, solid electrolytes described in JP-A No. 2007-141658, solid electrolytes described in JP-A No. 2007-163865, and gel electrolytes.

(Electronic insulation layer)
In the display element of the present invention, an electrical insulating layer can be provided.

  The electronic insulating layer applicable to the present invention may be a layer having both ionic conductivity and electronic insulating properties. For example, a solid electrolyte membrane in which a polymer or salt having a polar group is formed into a film, electronic insulating properties And a porous solid body having a low relative dielectric constant, such as a silicon-containing compound, and the like.

  As a method for forming a porous film, a sintering method (fusing method) (using fine pores formed between particles by partially fusing polymer fine particles or inorganic particles by adding a binder, etc.), extraction method ( After forming a constituent layer with a solvent-soluble organic substance or inorganic substance and a binder that does not dissolve in the solvent, the organic substance or inorganic substance is dissolved with the solvent to obtain pores), and the polymer is heated or degassed Known forming methods such as foaming method for foaming, phase change method for phase separation of polymer mixture by manipulating good solvent and poor solvent, radiation irradiation method for radiating various radiations to form pores, etc. Can be used. Specifically, JP-A-10-30181, JP-A-2003-107626, JP-B-7-95403, JP-A-2635715, JP-A-2894523, JP-A-2987474, JP-A-3066426, and JP-A-3464513. No. 3,483,464, No. 3535942, No. 30622203, and the like.

[Thickener added with electrolyte]
In the display element of the present invention, a thickener can be used for the electrolyte. For example, gelatin, gum arabic, poly (vinyl alcohol), hydroxyethyl cellulose, hydroxypropyl cellulose, cellulose acetate, cellulose acetate butyrate, poly ( Vinylpyrrolidone), poly (alkylene glycol), casein, starch, poly (acrylic acid), poly (methyl methacrylic acid), poly (vinyl chloride), poly (methacrylic acid), copoly (styrene-maleic anhydride), copoly ( Styrene-acrylonitrile), copoly (styrene-butadiene), poly (vinyl acetal) s (eg, poly (vinyl formal) and poly (vinyl butyral)), poly (esters), poly (urethanes), phenoxy resins, poly (PVC Redene), poly (epoxides), poly (carbonates), poly (vinyl acetate), cellulose esters, poly (amides), hydrophobic transparent binders such as polyvinyl butyral, cellulose acetate, cellulose acetate butyrate, polyester, Examples include polycarbonate, polyacrylic acid, polyurethane and the like.

  These thickeners may be used in combination of two or more. Moreover, the compound as described in pages 71-75 of Unexamined-Japanese-Patent No. 64-13546 can be mentioned. Among these, the compounds preferably used are polyvinyl alcohols, polyvinyl pyrrolidones, hydroxypropyl celluloses, and polyalkylene glycols from the viewpoint of compatibility with various additives and improvement in dispersion stability of white particles.

  In the display element of the present invention, polyethylene glycol having an average polymerization degree of 100 to 500 is preferable as the thickener, and it is preferably added in a range of 5 to 20% by mass ratio with respect to the organic solvent of the electrolyte layer. .

[Other additives]
Examples of the constituent layers of the display element of the present invention include auxiliary layers such as a protective layer, a filter layer, an antihalation layer, a crossover light cut layer, and a backing layer. Sensitizer, noble metal sensitizer, photosensitive dye, supersensitizer, coupler, high boiling point solvent, antifoggant, stabilizer, development inhibitor, bleach accelerator, fixing accelerator, color mixing inhibitor, formalin scavenger, Toning agents, hardeners, surfactants, thickeners, plasticizers, slip agents, UV absorbers, anti-irradiation dyes, filter light absorbing dyes, anti-bacterial agents, polymer latex, heavy metals, antistatic agents, matting agents Etc. can be contained as required.

  These additives mentioned above are more specifically described in Research Disclosure (hereinafter abbreviated as RD), Volume 176 Item / 17643 (December 1978), Volume 184, Item / 18431 (August 1979), 187. Volume Item / 18716 (November 1979) and Volume 308 Item / 308119 (December 1989).

  The types of compounds and their descriptions shown in these three research disclosures are listed below.

Additive RD17643 RD18716 RD308119
Page Classification Page Classification Page Classification Chemical sensitizer 23 III 648 Upper right 96 III
Sensitizing dye 23 IV 648-649 996-8 IV
Desensitizing dye 23 IV 998 IV
Dye 25-26 VIII 649-650 1003 VIII
Development accelerator 29 XXI 648 Upper right Anti-fogging agent / stabilizer
24 IV 649 Upper right 1006-7 VI
Brightener 24 V 998 V
Hardener 26 X 651 Left 1004-5 X
Surfactant 26-7 XI 650 Right 1005-6 XI
Antistatic agent 27 XII 650 Right 1006-7 XIII
Plasticizer 27 XII 650 Right 1006 XII
Slipper 27 XII
Matting agent 28 XVI 650 Right 1008-9 XVI
Binder 26 XXII 1003-4 IX
Support 28 XVII 1009 XVII
〔substrate〕
The substrate that can be used in the present invention is preferably a transparent substrate. Examples of such a transparent substrate include polyester (for example, polyethylene terephthalate), polyimide, polymethyl methacrylate, polystyrene, polypropylene, polyethylene, and polyamide. Nylon, polyvinyl chloride, polyvinylidene chloride, polycarbonate, polyether sulfone, silicon resin, polyacetal resin, fluororesin, cellulose derivative, polyolefin and other polymer films, plate substrates, glass substrates, and the like are preferably used. The transparent substrate used in the present invention refers to a substrate having a transmittance for visible light of at least 50%.

  Further, as the counter substrate, for example, an opaque substrate such as an inorganic substrate such as a metal substrate or a ceramic substrate can be used.

〔electrode〕
In the display element of the present invention, the nitrogen-containing functional group is oriented on the surface of the carbon material, and the auxiliary compound that can be electrochemically oxidized and reduced is immobilized on the nitrogen functional group. Various known electrodes can be used together with the electrodes.

(Display side transparent electrode)
Of the counter electrodes, the electrode positioned on the display side is preferably a transparent electrode.

  The transparent electrode is not particularly limited as long as it is transparent and conducts electricity. For example, Indium Tin Oxide (ITO: Indium Tin Oxide), Indium Zinc Oxide (IZO: Indium Zinc Oxide), Fluorine Doped Tin Oxide (FTO), Indium Oxide, Zinc Oxide, Platinum, Gold, Silver, Rhodium, Copper, Examples thereof include chromium, carbon, aluminum, silicon, amorphous silicon, and BSO (Bismuth Silicon Oxide).

  In addition, polythiophene, polypyrrole, polyaniline, polyacetylene, polyparaphenylene, polyselenophenylene, etc., and their modifying compounds can be used alone or in combination.

  The surface resistance value is preferably 100Ω / □ or less, and more preferably 10Ω / □ or less. The thickness of the transparent electrode is not particularly limited, but is generally 0.1 to 20 μm.

(Transparent porous electrode)
As one embodiment of the transparent electrode, a nanoporous electrode having a nanoporous structure can be provided on the transparent electrode. This nanoporous electrode is substantially transparent when a display element is formed, and can carry an electroactive substance such as an electrochromic dye.

  The nanoporous structure as used in the present invention refers to a state in which an infinite number of nanometer-sized pores exist in a layer and ionic species contained in the electrolyte can move within the nanoporous structure.

  As a method for forming such a nanoporous electrode, a dispersion containing fine particles constituting the nanoporous electrode is formed in layers by an ink jet method, a screen printing method, a blade coating method, etc., and then heated at a predetermined temperature. A method of making porous by drying, baking, a method of making nanoporous by forming an electrode layer by sputtering, CVD, atmospheric pressure plasma, etc., and then anodizing, photoelectrochemical etching, etc. Is mentioned. Also, the sol-gel method, Adv. Mater. It can also be formed by the method described in 2006, 18, 2980-2983.

The main components of the fine particles constituting the nanoporous electrode are metals such as Cu, Al, Pt, Ag, Pd and Au, metal oxides such as ITO, SnO ₂ , TiO ₂ and ZnO, carbon nanotubes, glassy carbon, and diamond. It can be selected from carbon electrodes such as like carbon and nitrogen-containing carbon, and is preferably selected from metal oxides such as ITO, SnO ₂ , TiO ₂ , and ZnO.

  In order for the nanoporous electrode to have transparency, it is preferable to use fine particles having an average particle diameter of about 5 nm to 10 μm. As the shape of the fine particles, those having an arbitrary shape such as an indefinite shape, a needle shape, and a spherical shape can be used.

  The film thickness of the nanoporous electrode is preferably in the range of 0.1 to 10 μm, more preferably in the range of 0.25 to 5 μm.

(Grid electrode: auxiliary electrode)
An auxiliary electrode can be attached to at least one of the counter electrodes according to the present invention.

  The auxiliary electrode is preferably made of a material having a lower electrical resistance than the main electrode portion. For example, metals such as platinum, gold, silver, copper, aluminum, zinc, nickel, titanium, bismuth, and alloys thereof can be preferably used.

  The auxiliary electrode can be installed either between the main electrode portion and the substrate, or on the surface of the main electrode portion opposite to the substrate. In any case, it is only necessary that the auxiliary electrode is electrically connected to the main electrode portion.

  There are no particular restrictions on the arrangement pattern of the auxiliary electrodes. It can be appropriately formed according to the required performance, such as linear, mesh, or circular. When the main electrode part is divided into a plurality of parts, the divided electrode parts may be connected to each other. However, in the case where the main electrode portion is a transparent electrode provided on the display-side substrate, the auxiliary electrode is required to be provided with a shape and frequency that do not impair the visibility of the display element.

  As a method of forming the auxiliary electrode, a known method can be used. For example, patterning by a photolithographic method, printing method, ink jet method, electrolytic plating, electroless plating, or a method of forming a pattern by exposing and developing using a silver salt photosensitive material may be used.

  The line width and line spacing of the auxiliary electrode pattern may be arbitrary values, but the line width needs to be increased in order to increase the conductivity. On the other hand, when an auxiliary electrode is attached to the transparent electrode, from the viewpoint of visibility, the area coverage of the auxiliary electrode viewed from the display element observation side is preferably 30% or less, and more preferably 10% or less.

  Thus, from the viewpoint of transmittance and conductivity, the line width of the auxiliary electrode is preferably 1 μm or more and 100 μm or less, and the line interval is preferably 50 μm to 1000 μm.

(Method of forming electrode)
A known method can be used to form the transparent electrode and the metal auxiliary electrode. For example, a method of depositing a mask on a substrate by sputtering or the like, a method of patterning by photolithography after forming the entire surface, and the like can be given.

  Electrodes can also be formed by electrolytic plating, electroless plating, printing methods, and ink jet methods.

  After forming an electrode pattern including a catalyst layer having a monomer polymerization ability on a substrate using an inkjet method, a monomer component that is polymerized by the catalyst and becomes a conductive polymer layer after polymerization is added, It is also possible to form a metal electrode pattern by polymerizing and further performing metal plating such as silver on the conductive polymer layer, so that a photoresist or mask pattern is not used. It can be simplified.

  When the electrode material is formed by a coating method, for example, a known method such as a dipping method, a spinner method, a spray method, a roll coater method, a flexographic printing method, a screen printing method, or the like can be used.

  Among the ink jet methods, the following electrostatic ink jet method is capable of continuously printing a highly viscous liquid with high accuracy and is preferably used for forming the transparent electrode and the metal auxiliary electrode of the present invention. The viscosity of the ink is preferably 30 mPa · s or more, and more preferably 100 mPa · s or more.

<Electrostatic inkjet method>
In the display element of the present invention, at least one of the transparent electrode of the composite electrode and the metal auxiliary electrode has a liquid discharge head having a nozzle with an internal diameter of 30 μm or less for discharging a charged liquid, and supplies a solution into the nozzle. It is one of the preferable embodiments that the liquid discharge device is provided with a supply unit that performs the discharge and a discharge voltage application unit that applies a discharge voltage to the solution in the nozzle. Further, it is preferable that the solution in the nozzle is formed by using a discharge device provided with a convex meniscus forming means for forming a state where the solution rises from the nozzle tip.

  In addition, it comprises operation control means for controlling application of drive voltage for driving the convex meniscus forming means and application of discharge voltage by the discharge voltage application means, and this operation control means applies application of the discharge voltage by the discharge voltage application means. It is also preferable to use a liquid ejection apparatus having a first ejection control unit that applies a driving voltage to the convex meniscus forming means when ejecting liquid droplets.

  In addition, an operation control unit that controls driving of the convex meniscus forming unit and voltage application by the discharge voltage applying unit is provided, and the operation control unit includes an operation for raising the solution by the convex meniscus forming unit, and application of the discharge voltage. A liquid discharge device having a second discharge control unit that synchronizes the liquid, and the operation control means includes a liquid level at the tip of the nozzle after the swell operation of the solution and the application of the discharge voltage. It is also a preferred form to use a liquid ejection apparatus having a liquid level stabilization control unit that performs operation control for drawing in the inside.

  By producing an electrode pattern using such an electrostatic inkjet, it is advantageous that an electrode having excellent on-demand characteristics, little waste material, and excellent dimensional accuracy can be obtained.

[Other components of the display element]
In the display element of the present invention, a sealant, a columnar structure, and spacer particles can be used as necessary.

  Sealing agent is for sealing so that it does not leak to the outside and is also called sealing agent. Epoxy resin, urethane resin, acrylic resin, vinyl acetate resin, ene-thiol resin, silicon resin, modified resin A curing type such as a polymer resin, such as a thermosetting type, a photocurable type, a moisture curable type, and an anaerobic curable type can be used.

  The columnar structure provides strong self-holding (strength) between the substrates, for example, a columnar body, a quadrangular columnar body, an elliptical columnar body, a trapezoidal array arranged in a predetermined pattern such as a lattice arrangement. A columnar structure such as a columnar body can be given. Alternatively, stripes arranged at predetermined intervals may be used. This columnar structure is not a random array, but can be properly maintained at intervals of the substrate, such as an evenly spaced array, an array in which the interval gradually changes, and an array in which a predetermined arrangement pattern is repeated at a constant period. The arrangement is preferably considered so as not to disturb the display. If the ratio of the area occupied by the columnar structure in the display area of the display element is 1 to 40%, a practically sufficient strength as a display element can be obtained.

  A spacer may be provided between the pair of substrates for uniformly maintaining a gap between the substrates. Examples of the spacer include a sphere made of resin or inorganic oxide. Further, a fixed spacer having a surface coated with a thermoplastic resin is also preferably used. In order to hold the gap between the substrates uniformly, only the columnar structure may be provided, but both the spacer and the columnar structure may be provided, or instead of the columnar structure, only the spacer is used as the space holding member. May be used. The diameter of the spacer is equal to or less than the height of the columnar structure, preferably equal to the height. When the columnar structure is not formed, the diameter of the spacer corresponds to the thickness of the cell gap.

[Display element driving method]
The driving operation of the display element of the present invention may be simple matrix driving or active matrix driving. The simple matrix driving in the present invention is a driving method in which a current is sequentially applied to a circuit in which a positive line including a plurality of positive electrodes and a negative electrode line including a plurality of negative electrodes are opposed to each other in a vertical direction. Say that. By using simple matrix driving, there is an advantage that the circuit configuration and driving IC can be simplified and manufactured at low cost. The active matrix drive is a system in which scanning lines, data lines, and current supply lines are formed in a grid pattern, and are driven by TFT circuits provided in each grid pattern. Since switching can be performed for each pixel, there are merits such as gradation and memory function. For example, a circuit described in FIG. 5 of JP-A-2004-29327 can be used.

[Product application]
The display element of the present invention can be used in an electronic book field, an ID card field, a public field, a traffic field, a broadcast field, a payment field, a distribution logistics field, and the like. Specifically, keys for doors, student ID cards, employee ID cards, various membership cards, convenience store cards, department store cards, vending machine cards, gas station cards, subway and railway cards, bus cards, Cash cards, credit cards, highway cards, driver's licenses, hospital examination cards, electronic medical records, health insurance cards, Basic Resident Registers, passports, electronic books, etc.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated concretely, this invention is not limited to these. In addition, although the display of "part" or "%" is used in an Example, unless otherwise indicated, "part by mass" or "mass%" is represented.

Example 1
<< Production of display element >>
(Preparation of electrolyte)
(Preparation of electrolyte 1)
In 2.5 g of dimethyl sulfoxide (DMSO), 0.1 g of bismuth chloride, 0.1 g of lithium bromide, and 0.025 g of spiro- (1,1 ′)-bipyrrolidinium tetrafluoroborate are dissolved. Got.

(Preparation of electrolyte 2)
In 2.5 g of dimethyl sulfoxide, 0.1 g of silver p-toluenesulfonate (also referred to as silver tosylate) and 0.025 g of spiro- (1,1 ′)-bipyrrolidinium tetrafluoroborate are dissolved. 2 was obtained.

(Preparation of electrolyte 3)
In 2.5 g of compound S1-4, 0.1 g of silver p-toluenesulfonate, 0.2 g of compound G2-12, and 0.025 g of spiro- (1,1 ′)-bipyrrolidinium tetrafluoroborate are dissolved. Thus, an electrolytic solution 3 was obtained.

(Preparation of electrolyte 4)
In 2.5 g of compound S1-4, 0.1 g of silver p-toluenesulfonate, 0.2 g of compound G1-3, and 0.025 g of spiro- (1,1 ′)-bipyrrolidinium tetrafluoroborate are dissolved. Thus, an electrolytic solution 4 was obtained.

[Production of electrodes]
(Production of electrode 1)
An ITO (Indium Tin Oxide) film was formed on a 2 cm × 4 cm glass substrate having a thickness of 1.5 mm according to a known method to obtain a transparent electrode (electrode 1).

(Preparation of electrode 2)
A silver film containing 2% palladium is formed on a 2 cm × 4 cm glass substrate having a thickness of 1.5 mm according to a known method, and then the following titanium dioxide dispersion is dried so that the average film thickness after drying is 20 μm. The electrode 2 on which the porous white scattering layer was formed by screen printing on the silver film obtained, and then drying at 50 ° C. for 30 minutes to evaporate the solvent and then drying in an atmosphere at 85 ° C. for 1 hour. Produced.

<Preparation of titanium dioxide dispersion>
Kuraray Poval PVA235 (manufactured by Kuraray Co., Ltd., polyvinyl alcohol resin) was added to a water / ethanol mixed solution so as to have a solid content concentration of 2% by mass, and dissolved by heating. Was dispersed with an ultrasonic disperser so as to be 20% by mass to obtain a titanium dioxide dispersion.

(Preparation of electrode 3)
The titanium dioxide dispersion was screen-printed on a 2 cm x 4 cm glassy carbon electrode with a thickness of 1.5 mm so that the average film thickness after drying was 20 µm, and then dried at 50 ° C for 30 minutes to evaporate the solvent. After that, the electrode 3 was formed by drying in an atmosphere at 85 ° C. for 1 hour to form a porous white scattering layer.

(Preparation of electrode 4)
A 1.5 mm thick 2 cm × 4 cm glassy carbon electrode was used as a working electrode, a platinum plate as a counter electrode, and a silver-silver chloride electrode as a reference electrode, and ALS630C manufactured by BAS was used, and 0.1 M (mol / liter) was used. An aqueous solution of ammonium carbamate was electrolytically oxidized.

  The electrolytic oxidation was performed for 1 hour by applying a constant potential (between 0.8 V and 1.3 V). During the constant potential electrolysis, the ammonium carbamate aqueous solution was stirred with a stirrer. After the electrolytic oxidation treatment, the working electrode was washed with distilled water to produce a carbon electrode to which an amino group that is a nitrogen-containing functional group was bonded.

  Next, the titanium dioxide dispersion is screen-printed so that the average film thickness after drying is 20 μm, then dried at 50 ° C. for 30 minutes to evaporate the solvent, and then dried in an atmosphere at 85 ° C. for 1 hour. Thus, an electrode 4 having a porous white scattering layer formed thereon was produced.

(Preparation of electrode 5)
A 1.5 mm thick 2 cm × 4 cm glassy carbon electrode is used as a working electrode, a platinum plate as a counter electrode, and a silver-silver chloride electrode as a reference electrode, and ALS630C manufactured by BAS Co., Ltd., 0.1 M (mol / liter) carbamine An aqueous ammonium acid solution was electrolytically oxidized.

  The electrolytic oxidation was performed for 1 hour by applying a constant potential (between 0.8 V and 1.3 V). In addition, the ammonium carbamate aqueous solution was stirred with the stirrer 20 during constant potential electrolysis. After the electrolytic oxidation treatment, the working electrode was washed with distilled water to produce a carbon electrode to which an amino group that is a nitrogen-containing functional group was bonded.

  Next, the carbon electrode to which the amino group obtained above was bonded was immersed in a solution obtained by dissolving the compound (M9) in acetonitrile so as to have a concentration of 0.3 mM, and further 1-ethyl-3- (3- (dimethylamino) Propyl) carbodiimide) was added and allowed to stand at room temperature overnight. The carbon electrode was washed with distilled water to prepare a carbon electrode in which the compound (M9) was fixed to the amino group with an amide bond.

  Next, the titanium dioxide dispersion is screen-printed so that the average film thickness after drying is 20 μm, then dried at 50 ° C. for 30 minutes to evaporate the solvent, and then dried in an atmosphere at 85 ° C. for 1 hour. Thus, an electrode 5 having a porous white scattering layer was produced.

  Using electrode 5 as a working electrode, a platinum plate as a counter electrode, and a silver-silver chloride electrode as a reference electrode, using ALS630C manufactured by BAS, cyclic voltammetry was measured in acetonitrile using tetrabutylammonium perchloride as an indicator salt, A redox peak derived from the compound (M9) was confirmed.

(Preparation of electrode 6)
An electrode 6 was produced in the same manner as the electrode 5 except that the compound (M9) was changed to the compound A-1.

(Preparation of electrode 7)
An electrode 7 was produced in the same manner as the electrode 5 except that the compound (M9) was changed to the compound (M56).

(Preparation of electrode 8)
A carbon felt electrode having a thickness of 1.5 mm and 2 cm × 4 cm is used as a working electrode, a platinum plate as a counter electrode, and a silver-silver chloride electrode as a reference electrode. An aqueous ammonium acid solution was electrolytically oxidized.

  The electrolytic oxidation was performed for 1 hour by applying a constant potential (between 0.8 V and 1.3 V). In addition, the ammonium carbamate aqueous solution was stirred with the stirrer 20 during constant potential electrolysis. After the electrolytic oxidation treatment, the working electrode was washed with distilled water to produce a carbon electrode to which an amino group that is a nitrogen-containing functional group was bonded.

  Next, the titanium dioxide dispersion is screen-printed so that the average film thickness after drying is 20 μm, then dried at 50 ° C. for 30 minutes to evaporate the solvent, and then dried in an atmosphere at 85 ° C. for 1 hour. Thus, an electrode 8 having a porous white scattering layer formed thereon was produced.

(Preparation of electrode 9)
A carbon felt electrode having a thickness of 1.5 mm and 2 cm × 4 cm is used as a working electrode, a platinum plate as a counter electrode, and a silver-silver chloride electrode as a reference electrode. An aqueous ammonium acid solution was electrolytically oxidized.

  The electrolytic oxidation was performed for 1 hour by applying a constant potential (between 0.8 V and 1.3 V). In addition, the ammonium carbamate aqueous solution was stirred with the stirrer 20 during constant potential electrolysis. After the electrolytic oxidation treatment, the working electrode was washed with distilled water to produce a carbon electrode to which an amino group that is a nitrogen-containing functional group was bonded.

  Next, the carbon electrode to which the amino group obtained above was bonded was immersed in a solution in which the compound (M9) was dissolved in acetonitrile so as to be 0.3 mmol, and further 1-ethyl-3- (3- (dimethylamino) was obtained. Propyl) carbodiimide) was added and allowed to stand at room temperature overnight. The carbon electrode was washed with distilled water to prepare a carbon electrode in which the compound (M9) was fixed to the amino group with an amide bond.

  Next, the titanium dioxide dispersion was screen-printed so that the average film thickness after drying was 20 μm, then dried at 50 ° C. for 30 minutes to evaporate the solvent, and then dried in an atmosphere at 85 ° C. for 1 hour. Thus, an electrode 9 having a porous white scattering layer formed thereon was produced.

  Using electrode 5 as a working electrode, a platinum plate as a counter electrode, and a silver-silver chloride electrode as a reference electrode, using ALS630C manufactured by BAS, cyclic voltammetry was measured in acetonitrile using tetrabutylammonium perchloride as an indicator salt, A redox peak derived from the compound (M9) was confirmed.

(Production of electrode 10)
An electrode 10 was produced in the same manner as the electrode 9 except that the compound (M9) was changed to the compound A-1.

[Production of display element]
(Preparation of display element 1-1)
The periphery of the electrode 2 is edged with an olefin-based sealant containing glass spherical beads having an average particle diameter of 40 μm as a volume fraction of 10%, and then bonded so that the electrode 2 and the electrode 1 are orthogonal to each other and further heated. An empty cell was produced by pressing. The electrolytic solution 1 was vacuum-injected into the empty cell, and the injection port was sealed with an epoxy-based ultraviolet curable resin to produce a display element 1-1.

(Production of display elements 1-2 to 1-16)
Display elements 1-2 to 1-16 were fabricated in the same manner as the display element 1-1 except that the electrolyte solution and the electrode were changed to the combinations shown in Table 1.

  In addition, the detail of the compound A-1 used for preparation of the display element 1-10 is as follows.

<< Evaluation of display element >>
[Evaluation of reflectance stability (repeated resistance) when driven repeatedly]
When both electrodes of the display element are connected to both terminals of the constant voltage power source, a voltage of +1.5 V is applied for 1 second, and then a voltage of -1.5 V is applied for 0.5 second to display gray The reflectance at a wavelength of 550 nm was measured with a spectrocolorimeter CM-3700d manufactured by Konica Minolta Sensing. Under the same driving conditions, driving was performed 10 times in total, and the average value of the obtained reflectances was defined as R _ave1 . Further, after driving repeatedly 10,000 times, R _ave2 was obtained by the same method. ΔR _BK1 = | R _ave1 −R _ave2 | was used as an index of stability of reflectance when ΔR _BK1 was repeatedly driven. Here, the smaller the value of ΔR _BK1, the better the stability of the reflectance when repeatedly driven, that is, the repeated resistance.

[Evaluation of rewriting speed of black display]
Connect both electrodes of the display element to both terminals of the constant voltage power source, apply a low voltage of +1.5 V to the display side electrode for 3 seconds to display white, and then apply a constant voltage of -1.5 V to 1 The reflectance at a wavelength of 550 nm when gray was applied for 2 seconds was measured with a spectrocolorimeter CM-3700d manufactured by Konica Minolta Sensing Co., Ltd., and the obtained value was defined as R _BK . Here, as the value of R _BK is small, resulting in faster rewriting speed of the black display.

  Table 1 shows the configurations and evaluation results of the display elements obtained as described above.

  As is apparent from the results shown in Table 1, it can be seen that the display element satisfying the configuration of the present invention has improved reflectance stability and rewriting speed when driven repeatedly compared to the comparative example.

Example 2
<< Production of display element >>
(Preparation of electrolyte)
(Preparation of electrolyte 5)
0.025 g of tetrafluoroborate spiro- (1,1 ′)-bipyrrolidinium was dissolved in 2.5 g of dimethyl sulfoxide to obtain an electrolytic solution 5.

(Preparation of electrolyte 6)
In 2.5 g of Compound S1-4, 0.025 g of spiro- (1,1 ′)-bipyrrolidinium tetrafluoroborate was dissolved to obtain an electrolytic solution 6.

(Preparation of electrode 11)
On the electrode 1 produced in Example 1, a titanium dioxide film having a thickness of 5 μm (about 4 to 10 particles having an average particle diameter of 17 nm had been necked) was formed. Next, after immersing the obtained electrode in a solution of compound (Ot1) in acetonitrile / ethanol so as to be 3 mmol / L for 1 hour at room temperature, the electrode was taken out and washed thoroughly with ethanol to obtain an electrode 11. Got.

(Preparation of electrode 12)
An electrode 12 was produced in the same manner as the electrode 11 except that the compound (Ot1) was changed to the compound (L26).

(Preparation of electrode 13)
An electrode 13 was produced in the same manner as the electrode 11 except that the compound (Ot1) was changed to the compound (L18).

(Preparation of electrode 14)
An electrode 14 was produced in the same manner as the electrode 11 except that the compound (Ot1) was changed to the compound (L1).

[Production of display element]
(Preparation of display element 2-1)
The periphery of the electrode 2 is bordered with an olefin sealant containing glass spherical beads having an average particle diameter of 40 μm as a volume fraction of 10%, and then bonded so that the electrode 2 and the electrode 11 are orthogonal to each other and further heated. An empty cell was produced by pressing. The electrolytic solution 5 was vacuum-injected into the empty cell, and the injection port was sealed with an epoxy-based ultraviolet curable resin to produce a display element 2-1.

(Preparation of display elements 2-2 to 2-18)
Display elements 2-2 to 2-18 were produced in the same manner as the display element 2-1, except that the electrolyte solution and the electrode were changed to the combinations shown in Table 2.

<< Evaluation of display element >>
[Evaluation of reflectance stability (repeated resistance) when driven repeatedly]
Visible when both electrodes of the display element are connected to both terminals of a constant voltage power supply, and a voltage of -1.5 V is applied for 1 second, and then a voltage of +1.5 V is applied for 0.5 second to cause color display. The reflectance at the maximum absorption wavelength in the light region was measured with a spectrocolorimeter CM-3700d manufactured by Konica Minolta Sensing. Under the same driving conditions, driving was performed 10 times in total, and the average value of the obtained reflectances was defined as R _ave3 . Further, after driving repeatedly 10,000 times, R _ave4 was obtained by the same method. ΔR _COLOR1 = | R _ave3 −R _ave4 | was used as an index of stability of reflectance when ΔR _COLOR1 was repeatedly driven. Here, the smaller the value of ΔR _COLOR1 , the _better the stability of the reflectance when repeatedly driven, that is, the repeated durability.

[Evaluation of rewriting speed of colored display]
Connect both electrodes of the display element to both terminals of the constant voltage power source, apply a low voltage of -1.5 V to the display side electrode for 3 seconds to display white, and then apply a constant voltage of +1.5 V to 1 The reflectance at the maximum absorption wavelength in the visible light region when applied and colored for 2 seconds was measured with a spectrocolorimeter CM-3700d manufactured by Konica Minolta Sensing Co., Ltd., and the obtained value was defined as R _COLOR . Here, the smaller the value of R _COLOR, the faster the rewriting speed of the colored display.

  Table 2 shows the configuration and evaluation results of each display element obtained as described above.

  As is apparent from the results shown in Table 2, it can be seen that the display element satisfying the configuration of the present invention has improved reflectance stability and rewriting speed when driven repeatedly compared to the comparative example.

Example 3
<< Production of display element >>
(Preparation of display element 3-1)
The periphery of the electrode 2 is bordered with an olefin sealant containing glass spherical beads having an average particle diameter of 40 μm as a volume fraction of 10%, and then bonded so that the electrode 2 and the electrode 11 are orthogonal to each other and further heated. An empty cell was produced by pressing. The electrolyte 3 was vacuum-injected into the empty cell, and the injection port was sealed with an epoxy-based ultraviolet curable resin to produce a display element 3-1.

(Preparation of display elements 3-2 to 3-20)
Display elements 3-2 to 3-20 were produced in the same manner as the display element 3-1, except that the electrolyte solution and the electrode were changed to the combinations shown in Table 3.

<< Evaluation of display element >>
In the same manner as in the method described in Example 1, the stability of the reflectance and the rewriting speed were evaluated when it was repeatedly driven between black and white display. Similarly, by the method described in Example 2, the evaluation of the stability of stability (repetition resistance) and the rewriting speed when it was repeatedly driven between colored display and white display were evaluated.

  Table 4 shows the configurations and evaluation results of the display elements obtained as described above.

  As is apparent from the results shown in Table 4, it can be seen that the display element satisfying the configuration of the present invention has improved reflectance stability and rewriting speed when driven repeatedly compared to the comparative example.

Claims (21)

Electricity characterized in that it contains at least a carbon material, nitrogen-containing functional groups are oriented on the surface of the carbon material, and auxiliary compounds that can be electrochemically oxidized and reduced are immobilized on the nitrogen-containing functional groups. Electrode for chemical display element. The electrode for an electrochemical display element according to claim 1, wherein an aqueous solution containing carbamic acid is electrolytically oxidized with a carbon electrode to orient a nitrogen-containing functional group on the surface of the carbon material. The electrode for an electrochemical display element according to claim 1, wherein the nitrogen-containing functional group is an amino group. The electrochemical display element according to any one of claims 1 to 3, wherein the carbon material is at least one selected from glassy carbon, carbon nanotube, carbon felt, plastic molded carbon, and diamond. Electrode. 5. The aqueous solution containing carbamic acid is at least one selected from an aqueous solution of ammonium carbamate, an aqueous solution of ammonium carbonate containing carbamic acid, and an aqueous solution of ammonium bicarbonate containing carbamic acid. 2. Electrode for electrochemical display device according to item 1. 6. The electrode for an electrochemical display element according to claim 1, wherein the auxiliary compound that can be electrochemically oxidized and reduced is a counter electrode reactant. The electrode for an electrochemical display element according to claim 6, wherein the counter electrode reactant is an N-oxyl derivative. The electrode for an electrochemical display element according to claim 6, wherein the counter electrode reactant is a metal complex having a compound represented by the following general formula [I] as an organic ligand.

[Wherein R ₃₁ , R ₃₂ , R ₃₃ and R ₃₄ are each independently a hydrogen atom, amino group, hydroxy group, mercapto group, alkoxy group, alkyl group, alkenyl group, alkynyl group, aryl group or heterocyclic group. These substituents may further have a substituent. R ₃₁ and R ₃₂ , R ₃₂ and R _33, and R ₃₃ and R ₃₄ may be connected to each other to form an aromatic or non-aromatic cyclic structure, and a substituent is present at any position on the ring. You may have. ] The electrode for an electrochemical display element according to any one of claims 1 to 8, wherein the counter electrode includes an electrolyte layer containing a metal salt compound and a white scattering material, and at least one of the counter electrodes is an electrode for an electrochemical display element according to any one of claims 1 to 8. A display element characterized by displaying black and white by applying a voltage between the counter electrodes. The display element according to claim 9, wherein the metal salt compound is a silver salt compound. The display element according to claim 9 or 10, wherein the electrolyte layer contains a compound represented by the following general formula (G-1) or (G-2).
General formula (G-1)
_{Rg 11} -S-Rg ₁₂
[Wherein, Rg ₁₁ and Rg ₁₂ each represent a substituted or unsubstituted hydrocarbon group. Further, these hydrocarbon groups may contain one or more nitrogen atom, oxygen atom, phosphorus atom, sulfur atom or halogen atom, and Rg ₁₁ and Rg ₁₂ may be connected to each other to take a cyclic structure. ]

[Wherein, M represents a hydrogen atom, a metal atom or quaternary ammonium. Z represents an atomic group necessary for constituting a nitrogen-containing heterocyclic ring. n represents an integer of 0 to 5, Rg ₂₁ represents a substituent, and when n is 2 or more, each Rg ₂₁ may be the same or different, and may be connected to each other to form a condensed ring. It may be formed. ] It has an electrochromic compound, an electrolyte layer, and a white scattering layer between the counter electrodes, and at least one of the counter electrodes is an electrode for an electrochemical display element according to any one of claims 1 to 8. A display element characterized by displaying a colored display other than black and white by applying a voltage between the counter electrodes. The display element according to claim 12, wherein the electrochromic compound is a compound represented by the following general formula (L).

[Wherein, Rl ₁ represents a substituted or unsubstituted aryl group, and Rl ₂ and Rl ₃ each represent a hydrogen atom or a substituent. X represents> N—Rl ₄ , an oxygen atom or a sulfur atom, and Rl ₄ represents a hydrogen atom or a substituent. ] The compound represented by the said general formula (L) is -COOH, -P = O (OH) ₂ , -OP = O (OH) _2, and -Si (OR) ₃ (R represents an alkyl group.) The display element according to claim 13, comprising at least one group selected from the group consisting of: The display device according to claim 13 or 14, wherein the compound represented by the general formula (L) is immobilized on an electrode surface. The electrochemical device according to any one of claims 1 to 8, wherein an electrochromic compound, an electrolyte layer containing a metal salt compound and a white scattering layer are provided between the counter electrodes, and at least one of the counter electrodes is electrochemical. A display element which is an electrode for a display element and displays a colored display other than black and white by applying a voltage between the counter electrodes. The display element according to claim 16, wherein the metal salt compound is a silver salt compound. The display element according to claim 16, wherein the electrolyte layer contains a compound represented by the following general formula (G-1) or (G-2).
General formula (G-1)
_{Rg 11} -S-Rg ₁₂
[Wherein, Rg ₁₁ and Rg ₁₂ each represent a substituted or unsubstituted hydrocarbon group. Further, these hydrocarbon groups may contain one or more nitrogen atom, oxygen atom, phosphorus atom, sulfur atom or halogen atom, and Rg ₁₁ and Rg ₁₂ may be connected to each other to take a cyclic structure. ]

[Wherein, M represents a hydrogen atom, a metal atom or quaternary ammonium. Z represents an atomic group necessary for constituting a nitrogen-containing heterocyclic ring. n represents an integer of 0 to 5, Rg ₂₁ represents a substituent, and when n is 2 or more, each Rg ₂₁ may be the same or different, and may be connected to each other to form a condensed ring. It may be formed. ] The display element according to claim 16, wherein the electrochromic compound is a compound represented by the following general formula (L).

[Wherein, Rl ₁ represents a substituted or unsubstituted aryl group, and Rl ₂ and Rl ₃ each represent a hydrogen atom or a substituent. X represents> N—Rl ₄ , an oxygen atom or a sulfur atom, and Rl ₄ represents a hydrogen atom or a substituent. ] The compound represented by the said general formula (L) is -COOH, -P = O (OH) ₂ , -OP = O (OH) _2, and -Si (OR) ₃ (R represents an alkyl group.) The display element according to claim 19, comprising at least one group selected from the group consisting of: The display device according to claim 19 or 20, wherein the compound represented by the general formula (L) is immobilized on an electrode surface.