JP6387673B2 - Electrochromic compound, electrochromic composition, display device and light control device - Google Patents

Description

  The present invention relates to an electrochromic compound, an electrochromic composition, and a display device and a light control device using the electrochromic compound or electrochromic composition that exhibit a black color when colored.

In recent years, electronic paper has been actively developed as an electronic medium replacing paper.
Since electronic paper is characterized in that the display device is used like paper, characteristics different from those of a conventional display device such as a CRT or a liquid crystal display are required. For example, it is a reflection type display device, has a high white reflectance and a high contrast ratio, can display a high definition, has a memory effect in display, can be driven even at a low voltage, is thin and light, and is inexpensive It is necessary to have characteristics such as Among these, in particular, as characteristics relating to display quality, there is a high demand for white reflectance and contrast ratio equivalent to paper.

  So far, as a display device for electronic paper, for example, a method using a reflective liquid crystal, a method using electrophoresis, a method using toner migration, and the like have been proposed, but among them, the mainstream is the electrophoresis method. Currently, it is widely used in electronic paper that is on the market as a product. However, it is difficult to give a high white reflectance particularly with this method, and it is known that this method shows a very low value of about 40% with respect to 80% for paper and 60% for newspaper. It has become a big issue.

As a promising technique for solving this problem and realizing a reflective display device, there is a method using an electrochromic phenomenon. When a voltage is applied, a phenomenon in which a redox reaction occurs reversibly according to the polarity and the color changes reversibly is called electrochromism. An electrochromic display device is a display device that utilizes the coloring / decoloring (hereinafter referred to as color erasing) of an electrochromic compound that causes this electrochromic phenomenon. Since this electrochromic display device is a reflective display device, has a memory effect, and can be driven at a low voltage, it is a leading candidate for display device technology for electronic paper use, from material development to device design. R & D has been conducted extensively. It has been confirmed that the white reflectance in this method is 60%, which is almost the same value as that of actual paper (Patent Document 1: Japanese Patent Application Laid-Open No. 2006-267829).
In an electrochromic display device, it is a method that can cover many of the above-mentioned problems, but it is used for a monochrome display element described in Patent Document 2 (Japanese Patent Laid-Open No. 2011-102287) created by this method. In the electrochromic compound, the color of the decolored state has a slight yellowishness, and the high white reflectance characteristic of this method cannot be realized.

  The present invention has been made in view of the above-described problems in the prior art. An electrochromic compound, an electrochromic composition (electrochromic composition) which develops a black color and does not have an absorption band at the time of decoloring and is colorless. An electrochromic composition in which a compound is bonded or adsorbed to a conductive or semiconducting nanostructure), and a display element having high white reflectance and high contrast using the electrochromic compound or electrochromic composition, or An object of the present invention is to provide a light control device having high transmittance and high contrast.

As a result of intensive studies, the present inventors have found that the above problems can be solved by using an electrochromic compound having a specific structure, and have reached the present invention.
That is, the said subject is solved by the "electrochromic compound" as described in following (1).
(1) “An electrochromic compound represented by the following general formula (I):

(In the formula, at least two of X ₁ , X ₂ and X ₃ of the general formula (I) have the structure of the general formula (II). When the structure of the general formula (II) is two, the remaining Any one of X ₁ , X ₂ , and X _{3 is} an aliphatic hydrocarbon group, an aromatic hydrocarbon group, or a hydrogen atom that may have a functional group, Y _{1 to} Y _8. Each independently represents a hydrogen atom or a monovalent group, which may have a substituent, R represents a monovalent group that may have a functional group, and The valent group may have a substituent, m is any one of 0 to _3. A ⁻ represents a monovalent anion, X ₁ , X ₂ , X ₃ in the general formula (I) The structures of Y ₁ to Y ₈ , m, and A ^{− in} the general formula (II) that are included may be independently different. ”

  As is clear from the following detailed and specific description, according to the present invention, a black-colored electrochromic compound or electrochromic composition having no absorption band at the time of decoloring and having a colorless decolored state is obtained. Can do.

It is the schematic which shows the structural example of the general display element using the electrochromic compound of this invention. It is the schematic which shows the structural example of the general display element using the electrochromic composition of this invention. It is the schematic which shows the structural example of the general light control element using the electrochromic composition of this invention. It is a figure which shows the absorption spectrum in the decoloring state and coloring state of the display electrode in which the electrochromic display layer produced in Example 1 was formed. It is a figure which shows the absorption spectrum in the decolored state of the electrochromic display element produced in Example 1, and the electrochromic display element produced in the comparative example 1. FIG. It is a figure which shows the comparison of the color value of the electrochromic display element produced in Example 1, and the electrochromic display element produced in the comparative example 1. FIG. It is a figure which shows the absorption spectrum in the decoloring state and coloring state of the display electrode in which the electrochromic display layer produced in Example 3 was formed.

Hereinafter, the present invention will be described in detail.
The present invention relates to the “electrochromic compound” described in (1) above, and this “electrochromic compound” includes the following aspects of “electrochromic compound” described in (2) to (6). To do. The present invention also includes the “display element” described in the following (7) and the “light control element” described in (8), and therefore the “electrochromic compound” described in (2) to (8). ”,“ Display element ”, and“ light control element ”will also be described in detail.
(2) “The electrochromic compound according to (1) above, wherein _two of X ₁ , X ₂ and X _{3 in} the general formula (I) have the structure of the general formula (II)”.
(3) The electrochromic as described in (1) or (2) above, wherein at least one of R in the general formula (II) has a functional group that can be directly or indirectly bonded to a hydroxyl group Compound".
(4) The above-mentioned (1) to (3), wherein at least one of X _{1 to} X _{3 in} the general formula (I) has a functional group that can be directly or indirectly bonded to a hydroxyl group. The electrochromic compound according to any one of the above.
(5) “The functional group that can be bonded directly or indirectly to the hydroxyl group is a group selected from a phosphonic acid group, a phosphoric acid group, a carboxylic acid group, a silyl group, or a silanol group” The electrochromic compound according to (3) or (4) above.
(6) “Electrochromic composition characterized in that the electrochromic compound according to any one of (1) to (5) and a conductive or semiconducting nanostructure are bonded or adsorbed”.
(7) “A display electrode, a counter electrode provided to face the display electrode at a distance from each other, and an electrolyte disposed between the two electrodes, and at least the (1 A display element comprising a display layer containing the electrochromic compound or electrochromic compound according to any one of (1) to (5) and the electrochromic composition according to (6) above.
(8) “A display electrode, a counter electrode provided to face the display electrode with a space therebetween, and an electrolyte disposed between the two electrodes, and at least an electrochromic compound on the surface of the display electrode Alternatively, in an element having an electrochromic composition, the electrochromic compound or electrochromic composition is the electrochromic compound according to any one of (1) to (5) or the electrochromic composition according to (6). A light control element characterized in that the display electrode, the counter electrode, and the electrolyte are transparent.
By using the electrochromic compound or the electrochromic composition of the present invention, a monochrome display element having high white reflectance and high contrast can be provided. Furthermore, it is possible to provide a monochrome light control device having high transparency and high contrast.

  As described above, as a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved if the electrochromic compound represented by the following general formula (I) is used. . That is, the electrochromic compound represented by the general formula (I) exhibits a black color, and is less colored when decolored.

（式中，一般式（Ｉ）のＸ_１，Ｘ₂，Ｘ₃のうち、少なくとも２つが一般式（ＩＩ）の構造を有する。一般式（ＩＩ）の構造が２つである場合，残りのＸ_１，Ｘ₂，Ｘ₃のいずれかの部位は官能基を有していてもよい脂肪族炭化水素基、芳香族炭化水素基、あるいは、水素原子のいずれかである。Y_１〜Y_８は各々独立に水素原子または一価の基を示し、これら一価の基は置換基を有していてもよい。Rは官能基を有していてもよい一価の基を示し、これら一価の基は置換基を有していてもよい。ｍは０〜３のいずれかである。Ａ⁻は１価のアニオンを表す。一般式（Ｉ）のＸ_１，Ｘ₂，Ｘ₃に入る一般式（ＩＩ）のY_１〜Y_８，ｍ，Ａ⁻の構造は独立して異なっていてもよい。

(In the formula, at least two of X ₁ , X ₂ and X ₃ of the general formula (I) have the structure of the general formula (II). When the structure of the general formula (II) is two, the remaining Any one of X ₁ , X ₂ , and X _{3 is} an aliphatic hydrocarbon group, an aromatic hydrocarbon group, or a hydrogen atom that may have a functional group, Y _{1 to} Y _8. Each independently represents a hydrogen atom or a monovalent group, which may have a substituent, R represents a monovalent group that may have a functional group, and The valent group may have a substituent, m is any one of 0 to _3. A ⁻ represents a monovalent anion, X ₁ , X ₂ , X ₃ in the general formula (I) The structures of Y ₁ to Y ₈ , m, and A ^{− in} the general formula (II) to be entered may be independently different.

In the general formula (II), the monovalent groups represented by Y _{1 to} Y ₈ are each independently a hydrogen atom, halogen atom, hydroxyl group, nitro group, cyano group, carboxyl group, carbonyl group, amide group, amino group. Carbonyl group, sulfonic acid group, sulfonyl group, sulfonamido group, aminosulfonyl group, amino group, alkyl group, alkenyl group, alkynyl group, aryl group, alkoxy group, aryloxy group, alkylthio group, arylthio group, and heterocyclic group The monovalent group selected from these is mentioned, These monovalent groups may have a substituent. Examples of the monovalent group represented by R include a monovalent group that may have a functional group selected from an alkyl group, an alkenyl group, an alkynyl group, and an aryl group. The group may have a substituent. Here, as the carbonyl group which may have a substituent, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkylcarbonyl group, an arylcarbonyl group and the like may have a substituent. As a monoalkylaminocarbonyl group, a dialkylaminocarbonyl group, a monoarylaminocarbonyl group, a diarylaminocarbonyl group, etc., and as the sulfonyl group, an alkoxysulfonyl group, an aryloxysulfonyl group, an alkylsulfonyl group, an arylsulfonyl group, etc. However, the aminosulfonyl group optionally having a substituent includes a monoalkylaminosulfonyl group, a dialkylaminosulfonyl group, a monoarylaminosulfonyl group, a diarylaminosulfonyl group, and the like, Te is a monoalkylamino group, such as dialkylamino group may be mentioned, respectively.

That is, in the general formula (II), the monovalent group represented by Y _{1 to} Y ₈ has a hydrogen atom, a halogen atom, a hydroxyl group, a nitro group, a cyano group, a carboxyl group, or a substituent. Alkoxycarbonyl group, optionally substituted aryloxycarbonyl group, optionally substituted alkylcarbonyl group, optionally substituted arylcarbonyl group, amide group, substituted A monoalkylaminocarbonyl group which may have a group, a dialkylaminocarbonyl group which may have a substituent, a monoarylaminocarbonyl group which may have a substituent, and a substituent. Diarylaminocarbonyl group, sulfonic acid group, alkoxysulfonyl group which may have a substituent, aryl which may have a substituent Xylsulfonyl group, optionally substituted alkylsulfonyl group, optionally substituted arylsulfonyl group, sulfonamide group, optionally substituted monoalkylaminosulfonyl group, substituted A dialkylaminosulfonyl group which may have a group, a monoarylaminosulfonyl group which may have a substituent, a diarylaminosulfonyl group which may have a substituent, an amino group and a substituent A monoalkylamino group which may have a substituent, a dialkylamino group which may have a substituent, an alkyl group which may have a substituent, an alkenyl group which may have a substituent, and a substituent. An alkynyl group which may have a substituent, an aryl group which may have a substituent, an alkoxy group which may have a substituent, an aryl which may have a substituent Oxy group which may have a substituent alkylthio group which may have a substituent arylthio group, and a heterocyclic group which may have a substituent. In addition, as the monovalent group represented by B, each independently an alkyl group which may have a functional group, an alkenyl group which may have a functional group, or an alkynyl which may have a functional group Groups, and aryl groups which may have a functional group, and the like, and these monovalent groups may have a substituent.

Since the monovalent group of Y _{1 to} Y ₈ can impart solubility of the electrochromic compound to the solvent, the device manufacturing process is facilitated. On the other hand, the stability such as heat resistance and light resistance is likely to be lowered by these groups. Therefore, a hydrogen atom, a halogen, or a substituent having 6 or less carbon atoms is preferable.

A ⁻ represents a monovalent anion and is not particularly limited as long as it forms a stable pair with the cation moiety, but bromine ion (Br ⁻ ), chlorine ion (Cl ⁻ ), perchlorate ion ( ClO ₄ ⁻ ), hexafluorophosphate ion (PF ₆ ⁻ ), tetrafluoroborate ion (BF ₄ ⁻ ), trifluoromethanesulfonate ion (CF ₃ SO ₃ ⁻ ) and the like are preferable.

In the electrochromic compound of the present invention, two or three of X _{1 to} X _{3 in} the general formula (I) have the structure of the general formula (II). In the case of three, the color of black is colored in both cases, but in the case of two, the solubility of the electrochromic compound is higher and the device fabrication process becomes easier.

  The electrochromic compound of the present invention preferably has a functional group that can be directly or indirectly bonded to a hydroxyl group. The functional group that can be directly or indirectly bonded to the hydroxyl group may be any functional group that can be directly or indirectly bonded to the hydroxyl group by hydrogen bonding, adsorption or chemical reaction, and the structure is limited. Although not preferred, preferred examples include phosphonic acid groups, phosphoric acid groups, trichlorosilyl groups, trialkoxysilyl groups, monochlorosilyl groups, monoalkoxysilyl groups, and other silyl groups (or silanol groups) and carboxyl groups. Can be mentioned. The trialkoxysilyl group is preferably a triethoxysilyl group or a trimethoxysilyl group. Among these, a phosphonic acid group or a silyl group (trialkoxysilyl group or trihydroxysilyl group) having a high binding force to the conductive or semiconducting nanostructure is particularly preferable.

As the position of the functional group that can be bonded directly or indirectly to the hydroxyl group, the R site in the general formula (II) is the best. In the structure in which two general formulas (II) are introduced with respect to X ₁ , X ₂ , and X ₃ in general formula (I), the remaining one of X ₁ , X ₂ , and X ₃ You may introduce | transduce the functional group which can be couple | bonded directly or indirectly with respect to a hydroxyl group. Of course, the number of functional groups that can be directly or indirectly bonded to the hydroxyl group is not limited to one, and two or three functional groups may be introduced.

  Specific examples of the electrochromic compound of the present invention are shown in the following structural formulas (3) to (29), but the electrochromic compound of the present invention is not limited thereto.

The electrochromic composition according to the present invention is characterized in that a conductive or semiconducting nanostructure is bonded to the electrochromic compound of the present invention [electrochromic compound represented by the general formula (I)]. It is what.
The electrochromic composition of the present invention exhibits a black color when used in an electrochromic display element, and further has excellent image memory properties, that is, a color image retention property. Note that the conductive or semiconducting nanostructure is a structure having nanoscale unevenness such as a nanoparticle or a nanoporous structure.

  As described above, when the functional group that can be directly or indirectly bonded to the hydroxyl group in the general formula (I), for example, the electrochromic compound of the present invention has a sulfonic acid group or When it has a phosphoric acid group or a carboxyl group, the electrochromic compound is easily complexed with the nanostructure and becomes an electrochromic composition having excellent color image retention. A plurality of the sulfonic acid group, phosphoric acid group and carboxyl group may be present in the electrochromic compound. In addition, when the electrochromic compound of the present invention has a silyl group or a silanol group, it is bonded to the nanostructure through a siloxane bond, and the bond becomes strong, and a stable electrochromic composition is also obtained. . The siloxane bond referred to here is a chemical bond via a silicon atom and an oxygen atom. In addition, the electrochromic composition only needs to have a structure in which the electrochromic compound and the nanostructure are bonded via a siloxane bond, and the bonding method and form thereof are not particularly limited.

  The material constituting the conductive or semiconducting nanostructure is preferably a metal oxide in terms of transparency and conductivity. Examples of such metal oxides include titanium oxide, zinc oxide, tin oxide, zirconium oxide, cerium oxide, yttrium oxide, boron oxide, magnesium oxide, strontium titanate, potassium titanate, barium titanate, calcium titanate. Metal oxides mainly composed of calcium oxide, ferrite, hafnium oxide, tungsten oxide, iron oxide, copper oxide, nickel oxide, cobalt oxide, barium oxide, strontium oxide, vanadium oxide, aluminosilicate, calcium phosphate, aluminosilicate, etc. Used. Moreover, these metal oxides may be used independently and 2 or more types may be mixed and used.

  In view of physical properties such as electrical properties and optical properties such as electrical conductivity, from metal oxides such as titanium oxide, zinc oxide, tin oxide, zirconium oxide, iron oxide, magnesium oxide, indium oxide and tungsten oxide When one kind selected or a mixture thereof is used, the response speed of color development and decoloration is excellent. In particular, when titanium oxide is used, the response speed of color development and decoloration is more excellent.

The shape of the metal oxide is preferably metal oxide fine particles having an average primary particle diameter of 30 nm or less. As the particle diameter is smaller, the light transmittance with respect to the metal oxide is improved, and a shape having a larger surface area per unit volume (hereinafter referred to as “specific surface area”) is used. By having a large specific surface area, the electrochromic compound is more efficiently supported, and a multicolor display with an excellent display contrast ratio for color development and decoloration is possible. Although the specific surface area of a nanostructure is not specifically limited, For example, it can be 100 m < ² > / g or more.

Next, the display element according to the present invention will be described.
A display element of the present invention includes a display electrode, a counter electrode provided to face the display electrode with a space therebetween, and an electrolyte disposed between both electrodes, and the display electrode on the counter electrode side of the display electrode It has the display layer containing the electrochromic compound represented by the said general formula (I) on the surface.

  FIG. 1 shows a configuration example of a general display element using the electrochromic compound of the present invention. As shown in FIG. 1, a display element 10 of the present invention includes a display electrode 1, a counter electrode 2 provided to face the display electrode 1 at a distance from each other, and both electrodes (opposing the display electrode 1 And an electrolyte 3 in which at least the electrochromic compound (organic electrochromic compound) 4 described in the present invention is dissolved. In the present display element, the electrochromic compound develops and discolors only on the electrode surface by a redox reaction.

FIG. 2 shows another structural example of a general display element using the electrochromic compound of the present invention.
The display element 20 of the present invention is disposed between the display electrode 1, the counter electrode 2 provided to face the display electrode 1 with a space therebetween, and both electrodes (the display electrode 1 and the counter electrode 2). And a display layer 5 including at least the electrochromic composition 4 a of the present invention on the surface of the display electrode 1. The counter electrode 2 has a white reflective layer 6 made of white particles on the display electrode 1 side.
As the electrochromic compound in the electrochromic composition of the present invention, a functional group (adsorptive group) that can be directly or indirectly bonded to a hydroxyl group in the molecular structure, that is, a compound having a so-called bonding group is used. Therefore, the bonding group can be bonded to a conductive or semiconducting nanostructure to form an electrochromic composition. The electrochromic composition is provided in a layered manner on the display electrode 1 to form the display layer 5.

Hereinafter, constituent materials used for the electrochromic display elements 10 and 20 according to the embodiment of the present invention will be described.
As a material constituting the display electrode 1, it is desirable to use a transparent conductive substrate. The transparent conductive substrate is preferably glass or a plastic film coated with a transparent conductive thin film.
The transparent conductive thin film material is not particularly limited as long as it is a conductive material, but a transparent conductive material that is transparent and excellent in conductivity is used because it is necessary to ensure light transmission. . Thereby, the visibility of the color to develop can be improved more.
As the transparent conductive material, it is possible to use an inorganic material such as tin-doped indium oxide (abbreviation: ITO), fluorine-doped tin oxide (abbreviation: FTO), or antimony-doped tin oxide (abbreviation: ATO). In particular, an inorganic material containing any one of indium oxide (hereinafter referred to as In oxide), tin oxide (hereinafter referred to as Sn oxide), or zinc oxide (hereinafter referred to as Zn oxide) It is preferable that In oxides, Sn oxides, and Zn oxides are materials that can be easily formed by a sputtering method, and are excellent in transparency and electrical conductivity. Particularly preferable materials are InSnO, GaZnO, SnO, In ₂ O ₃ and ZnO.
Examples of the material constituting the display substrate (not shown) on which the display electrode 1 is provided include glass or plastic. If a plastic film is used as the display substrate, a lightweight and flexible display element can be manufactured.

As the counter electrode 2, a transparent conductive film such as ITO, FTO, or zinc oxide, a conductive metal film such as zinc or platinum, or carbon is used. The counter electrode 2 is also generally formed on a counter substrate (not shown). The counter electrode substrate is also preferably glass or plastic film. When a metal plate such as titanium or zinc is used as the counter electrode 2, the counter electrode 2 also serves as a substrate.
Further, when the material constituting the counter electrode 2 includes a material that causes a reverse reaction opposite to the oxidation-reduction reaction caused by the electrochromic composition of the display layer, stable color development and decoloration is possible. That is, when the electrochromic composition is colored by oxidation, a reduction reaction is caused. When the electrochromic composition is colored by reduction, a material that causes an oxidation reaction is used as the counter electrode 2. The reaction of color development and decoloration in 5 becomes more stable.

As a material constituting the electrolyte 3, a material in which a supporting salt is dissolved in a solvent is generally used.
As the supporting salt, for example, inorganic ion salts such as alkali metal salts and alkaline earth metal salts, quaternary ammonium salts, acids, and alkali supporting salts can be used. Specific examples include LiClO ₄ , LiBF ₄ , LiAsF ₆ , LiPF ₆ , CF ₃ SO ₃ Li, CF ₃ COOLi, KCl, NaClO ₃ , NaCl, NaBF ₄ , NaSCN, KBF ₄ , Mg (ClO ₄ ) _2. Mg (BF ₄ ) ₂ or the like can be used.

  Examples of the solvent include propylene carbonate, acetonitrile, γ-butyrolactone, ethylene carbonate, sulfolane, dioxolane, tetrahydrofuran, 2-methyltetrahydrofuran, dimethyl sulfoxide, 1,2-dimethoxyethane, 1,2-ethoxymethoxyethane, and polyethylene glycol. , Alcohols are used.

In addition, since it is not particularly limited to a liquid electrolyte in which a supporting salt is dissolved in a solvent, a gel electrolyte or a solid electrolyte such as a polymer electrolyte is also used. For example, there are solid systems such as perfluorosulfonic acid polymer membranes. The solution system has an advantage of high ionic conductivity, and the solid system is suitable for producing a highly durable element without deterioration.
When the display element of the present invention is used as a reflective display element, it is desirable to provide a white reflective layer 6 between the display electrode 1 and the counter electrode 2 as shown in FIG. For the white reflective layer 6, it is the simplest production method to disperse white pigment particles in a resin and apply it on the counter electrode 2.
As the white pigment fine particles, particles made of a general metal oxide can be applied, and specific examples include titanium oxide, aluminum oxide, zinc oxide, silicon oxide, cesium oxide, yttrium oxide and the like. Moreover, it can also serve as a white reflective layer by mixing white pigment particles in the polymer electrolyte.

  As a driving method of the display elements 10 and 20, any method may be used as long as an arbitrary voltage and current can be applied. If a passive driving method is used, an inexpensive display element can be manufactured. Further, if the active driving method is used, high-definition and high-speed display can be performed. Active driving can be easily performed by providing an active driving element on the counter substrate.

FIG. 3 shows a configuration example of another general light control device using the electrochromic compound of the present invention.
The light control element 30 of the present invention is disposed between the display electrode 1, the counter electrode 2 provided to face the display electrode 1 with a space therebetween, and both electrodes (the display electrode 1 and the counter electrode 2). And a display layer 5 containing at least the electrochromic composition 4 a of the present invention on the surface of the display electrode 1.
As the electrochromic compound in the electrochromic composition of the present invention, a functional group (adsorptive group) that can be directly or indirectly bonded to a hydroxyl group in the molecular structure, that is, a compound having a so-called bonding group is used. Therefore, the bonding group can be bonded to a conductive or semiconducting nanostructure to form an electrochromic composition. The electrochromic composition is provided in a layered manner on the display electrode 1 to form the display layer 5.

Hereinafter, the constituent material used for the electrochromic light control element 30 according to the embodiment of the present invention will be described.
As a material constituting the display electrode 1, it is necessary to use a transparent conductive substrate. The transparent conductive substrate is preferably glass or a plastic film coated with a transparent conductive thin film.
The transparent conductive thin film material is not particularly limited as long as it is a conductive material, but a transparent conductive material that is transparent and excellent in conductivity is used because it is necessary to ensure light transmission. . Thereby, the visibility of the color to develop can be improved more.
As the transparent conductive material, it is possible to use an inorganic material such as tin-doped indium oxide (abbreviation: ITO), fluorine-doped tin oxide (abbreviation: FTO), or antimony-doped tin oxide (abbreviation: ATO). In particular, an inorganic material containing any one of indium oxide (hereinafter referred to as In oxide), tin oxide (hereinafter referred to as Sn oxide), or zinc oxide (hereinafter referred to as Zn oxide) It is preferable that In oxides, Sn oxides, and Zn oxides are materials that can be easily formed by a sputtering method, and are excellent in transparency and electrical conductivity. Particularly preferable materials are InSnO, GaZnO, SnO, In ₂ O ₃ and ZnO.

Examples of the material constituting the display substrate (not shown) on which the display electrode 1 is provided include glass or plastic. If a plastic film is used as the display substrate, a lightweight and flexible display element can be manufactured.
As with the display electrode 1, the counter electrode 2 also needs to use a transparent conductive substrate. The transparent conductive substrate is preferably glass or a plastic film coated with a transparent conductive thin film.

The transparent conductive thin film material is not particularly limited as long as it is a conductive material, but a transparent conductive material that is transparent and excellent in conductivity is used because it is necessary to ensure light transmission. . Thereby, the visibility of the color to develop can be improved more.
As the transparent conductive material, it is possible to use an inorganic material such as tin-doped indium oxide (abbreviation: ITO), fluorine-doped tin oxide (abbreviation: FTO), or antimony-doped tin oxide (abbreviation: ATO). In particular, an inorganic material containing any one of indium oxide (hereinafter referred to as In oxide), tin oxide (hereinafter referred to as Sn oxide), or zinc oxide (hereinafter referred to as Zn oxide) It is preferable that In oxides, Sn oxides, and Zn oxides are materials that can be easily formed by a sputtering method, and are excellent in transparency and electrical conductivity. Particularly preferable materials are InSnO, GaZnO, SnO, In ₂ O ₃ and ZnO.

Similarly to the display electrode 1, examples of the material constituting the display substrate (not shown) provided with the counter electrode 2 include glass or plastic. If a plastic film is used as the display substrate, a lightweight and flexible display element can be manufactured.
Further, when the material constituting the counter electrode 2 includes a material that causes a reverse reaction opposite to the oxidation-reduction reaction caused by the electrochromic composition of the display layer, stable color development and decoloration is possible. That is, when the electrochromic composition is colored by oxidation, a reduction reaction is caused. When the electrochromic composition is colored by reduction, a material that causes an oxidation reaction is used as the counter electrode 2. The reaction of color development and decoloration in 5 becomes more stable.
As a material constituting the electrolyte 3, a material in which a supporting salt is dissolved in a solvent is generally used. In the case of a light control element, in particular, the electrolyte 3 needs to be colorless and transparent.

As the supporting salt, for example, inorganic ion salts such as alkali metal salts and alkaline earth metal salts, quaternary ammonium salts, acids, and alkali supporting salts can be used. Specific examples include LiClO ₄ , LiBF ₄ , LiAsF ₆ , LiPF ₆ , CF ₃ SO ₃ Li, CF ₃ COOLi, KCl, NaClO ₃ , NaCl, NaBF ₄ , NaSCN, KBF ₄ , Mg (ClO ₄ ) _2. Mg (BF ₄ ) ₂ or the like can be used.

Examples of the solvent include propylene carbonate, acetonitrile, γ-butyrolactone, ethylene carbonate, sulfolane, dioxolane, tetrahydrofuran, 2-methyltetrahydrofuran, dimethyl sulfoxide, 1,2-dimethoxyethane, 1,2-ethoxymethoxyethane, and polyethylene glycol. , Alcohols are used.
In addition, since it is not particularly limited to a liquid electrolyte in which a supporting salt is dissolved in a solvent, a gel electrolyte or a solid electrolyte such as a polymer electrolyte is also used. For example, there are solid systems such as perfluorosulfonic acid polymer membranes. The solution system has an advantage of high ionic conductivity, and the solid system is suitable for producing a highly durable element without deterioration.
As a method for driving the light control element 30, any method may be used as long as an arbitrary voltage and current can be applied. If a passive driving method is used, an inexpensive light control element can be manufactured. Further, if a transparent active drive element is used, high-definition and high-speed light control can be performed. For example, IGZO is an example of a transparent active drive element.

  Hereinafter, the electrochromic compound and the electrochromic composition of the present invention, and the display device or the light control device using the same will be described with reference to examples, but the present invention is not limited to these examples.

[Example 1]
<Synthesis of Electrochromic Compound (9) [Structural Formula (9)]>
<a> Synthesis of intermediate (9-1)

The flask was charged with 3.0 g of 2,4,6-trichloro-1,3,5-triazine and replaced with argon gas, and then dioxane (100 mL), phenylpyridineboronic acid pinacol ester (18.5 g), PdCl ₂ ( PPh ₃ ) ₂ (600 mg) was added. 2M K ₂ CO ₃ (17 mL) was added, and the mixture was stirred at 50 ° C. for 14 hours, and further stirred at room temperature for 16 hours. The contents were filtered through Celite, and water and chloroform were added to the filtrate to separate the organic layer. The aqueous layer was extracted with chloroform three times. The combined organic layers were washed with saturated brine, dried over sodium sulfate, and the filtrate was concentrated to obtain a crude product. (Yield 7.5 g)
Purified by silica gel chromatography (developing solvent CHCl3 / MeOH = 93/7), the obtained solid was dispersed and washed in chloroform / hexane, and the filtered solid was vacuum-dried to obtain the desired product as a white solid. (Yield 6.9g, Yield 78%)

<B> Synthesis of Electrochromic Compound (9) [Structural Formula (9)]

To a 25 ml three-necked flask, 0.5 g of the intermediate (9-1), 4.0 g of 8-bromooctylphosphonic acid, and 3.0 ml of dimethylformamide were added and reacted at 90 ° C. for 8 hours. After returning to room temperature, this solution was discharged into 2-propanol, and then the obtained solid content was dispersed in 2-propanol and then recovered and dried under reduced pressure at 100 ° C. for 2 days to obtain the desired product. It was.
Yield 1.1 g, yield 85%.

[Production and evaluation of electrochromic display elements]
(A) Formation of display electrode and electrochromic display layer First, a 25 mm × 30 mm glass substrate with an FTO conductive film (manufactured by AGC Fabricec) was prepared, and a titanium oxide nanoparticle dispersion liquid was prepared in a 19 mm × 15 mm region on the upper surface. (SP210 manufactured by Showa Titanium Co., Ltd.) was applied by spin coating and annealed at 120 ° C. for 15 minutes to form a titanium oxide particle film. A 1 wt% 2,2,3,3-tetrafluoropropanol solution of the compound represented by the structural formula (22) is applied to the titanium oxide particle film by a spin coating method as a coating solution, and annealed at 120 ° C. for 10 minutes. Thus, the display layer 5 in which the electrochromic compound was adsorbed on the surface of the titanium oxide particles was formed.
In addition, the structure of the produced electrochromic display element is based on the structure of FIG. 2 (except for the white reflective layer).

(B) Formation of white reflective layer Further, a solution in which 10 wt% of urethane paste (HW140SF manufactured by DIC) was dissolved as a binder polymer in a 2,2,3,3-tetrafluoropropanol solution was prepared. A paste in which 50 wt% of titanium oxide particles (trade name: CR90, manufactured by Ishihara Sangyo Co., Ltd., average particle size: about 250 nm) is dispersed is applied to the electrochromic layer surface by spin coating, and annealed at 120 ° C. for 5 minutes. As a result, a white reflective layer of about 1 μm was formed.

(C) Formation of counter electrode On the other hand, a glass substrate with an ITO conductive film of 25 mm × 30 mm (manufactured by Geomat Co., Ltd.) was prepared separately from the glass substrate, and used as a counter substrate.

(D) Production of electrochromic display element A display substrate and a counter substrate were bonded to each other through a 75 μm spacer to produce a cell. Next, an electrolyte solution in which 20% by weight of tetrabutylammonium perchlorate was dissolved in dimethyl sulfoxide was prepared and sealed in a cell to produce an electrochromic display element.

[Comparative Example 1]
An electrochromic compound represented by the following structural formula (44) represented by [Chemical Formula 46] described in Patent Document 2 (Japanese Patent Laid-Open No. 2011-102287) was synthesized.

  A display electrode and an electrochromic display layer were formed in exactly the same manner as in Examples 1 (a) to (d) except that the obtained electrochromic compound was used, thereby producing an electrochromic display element.

[Color-decoloration comparison test 1]
A display electrode (a) on which an electrochromic display layer prepared in Example 1 and Comparative Example 1 is formed is put in a quartz cell, and a platinum electrode is used as a counter electrode, and an Ag / Ag + electrode is used as a reference electrode. -7), and the inside of the cell was filled with an electrolytic solution in which 0.1 M of tetrabutylammonium perchlorate was dissolved in dimethyl sulfoxide. The quartz cell was irradiated with deuterium tungsten halogen light (Ocean Optics DH-2000), the transmitted light was detected with a spectrometer (Ocean Optics USB4000), and the absorption spectrum was measured. FIG. 4 shows absorption spectra in the decolored state and the colored state. In the decolored state before voltage application, there was no absorption in the entire visible range of 400 nm to 700 nm, and it was transparent. When a voltage of -1.5 V was applied using a potentiostat (ALS Co., Ltd. ALS-660C), black color was developed.
FIG. 5 shows a comparison of absorption spectra in the decolored state between the electrochromic display layer (d) of Example 1 and the electrochromic display layer (d) of Comparative Example 1. In Comparative Example 1, absorption was observed at around 400 nm even in the decolored state, and the decolored body was more colored than the electrochromic compound of Example 1.

Each electrochromic display element (d) produced in Example 1 and Comparative Example 1 was subjected to comparative evaluation of color development and decoloration. Evaluation of color development / decoloration was performed by irradiating diffused light using a spectrocolorimeter MCPD7700 manufactured by Otsuka Electronics Co., Ltd. The color value was evaluated in the color space of CIE L * a * b *, and a * vs b * was plotted in FIG.
In the coloring state after applying a voltage of −4.0 V to each display element, both the electrochromic display elements of Example 1 and Comparative Example 1 are very close to the origin of the a * vs b * plot, and are almost the same as black. I was able to confirm that it was colored.
In the decolored state before voltage application, Example 1 shows almost the same color in the a * vs b * plot as compared to Japan Color White plotted at the origin. On the other hand, regarding Comparative Example 1, the value of b * was large, and it was found that there was yellow coloring.
From the above results, it can be seen that when the electrochromic display elements of Example 1 and Comparative Example 1 are compared, Example 1 is less colored in a decolored state and has a higher white reflectance.

[Example 2]
[Production and evaluation of electrochromic light control devices]
(A) Formation of display electrode and electrochromic display layer First, a 25 mm × 30 mm glass substrate with an FTO conductive film (manufactured by AGC Fabricec) was prepared, and a titanium oxide nanoparticle dispersion liquid was prepared in a 19 mm × 15 mm region on the upper surface. (SP210 manufactured by Showa Titanium Co., Ltd.) was applied by spin coating and annealed at 120 ° C. for 15 minutes to form a titanium oxide particle film. A 1 wt% 2,2,3,3-tetrafluoropropanol solution of the compound represented by the structural formula (9) is applied to the titanium oxide particle film by a spin coating method as a coating solution, and annealed at 120 ° C. for 10 minutes. Thus, the display layer 5 in which the electrochromic compound was adsorbed on the surface of the titanium oxide particles was formed.
In addition, the structure of the produced electrochromic light control element is based on the structure of FIG. 3 (a white reflective layer is excluded).

(B) Formation of counter electrode On the other hand, a glass substrate with an ITO conductive film of 25 mm × 30 mm (manufactured by Geomatic Co., Ltd.) was prepared separately from the glass substrate, and used as a counter substrate.

(C) Production of electrochromic light control device The display substrate and the counter substrate were bonded to each other through a 75 μm spacer to produce a cell. Next, an electrolyte solution in which 20% by weight of tetrabutylammonium perchlorate was dissolved in dimethyl sulfoxide was prepared, and sealed in a cell to produce an electrochromic light control device.

[Color-decoloration test 2]
The light control device (c) produced in Example 2 was irradiated with deuterium tungsten halogen light (Ocean Optics DH-2000), the transmitted light was detected with a spectrometer (Ocean Optics USB4000), and the transmission spectrum was measured. did. In the decolored state before voltage application, there was no absorption in the entire visible range of 400 nm to 700 nm, and it was transparent. In particular, the transmittance at 550 nm was 80%. On the other hand, when a voltage was applied to this device at −6.0 V for 2 seconds, black color was developed, and it was confirmed that the transmittance at 550 nm was reduced to 25%.
From this result, a high-contrast light control device was obtained by using the electrochromic compound represented by the structural formula (9).

[Example 3]
<Synthesis of Electrochromic Compound (10) [Structural Formula (10)]>
<a> Synthesis of intermediate (10-1)

The flask was charged with 3.0 g of 2,4,6-trichloro-1,3,5-triazine and substituted with argon gas, and then dioxane (100 mL), pyridylboronic acid pinacol ester (9.0 g), PdCl ₂ (PPh ₃ ). ₂ (300 mg) was added. 2M K ₂ CO ₃ (14 mL) was added, and the mixture was stirred at 50 ° C. for 8 hours, and further stirred at room temperature for 10 hours. The contents were filtered through Celite, and water and chloroform were added to the filtrate to separate the organic layer. The aqueous layer was extracted with chloroform three times. The combined organic layers were washed with saturated brine, dried over sodium sulfate, and the filtrate was concentrated to obtain a crude product. (Yield 4.5 g)
Purification by silica gel chromatography (developing solvent CHCl ₃ / MeOH = 93/7), the obtained solid was dispersed and washed in chloroform / hexane, and the collected solid was dried under vacuum to obtain the desired product as a white solid. (Yield 4.1 g, Yield 81%).

<B> Synthesis of Electrochromic Compound (10) [Structural Formula (10)]

  In the same manner as in Example 1 <b>, the target product as a colorless powder was obtained using intermediate (10-1) and 8-bromooctylphosphonic acid.

[Production and evaluation of electrochromic display elements]
An electrochromic display element was produced in the same manner as in Example 1 except that the electrochromic compound used was changed to that synthesized in Example 3.

[Color-decoloration test 3]
The result of measuring the absorption spectrum by the same method as in Example 1 is shown in FIG. In the decolored state before voltage application, there was no absorption in the entire visible range of 400 nm to 700 nm, and it was transparent. When a voltage of -1.5 V was applied using a potentiostat (ALS Co., Ltd. ALS-660C), black color was developed.

  When -3V was applied to the electrochromic display device produced in each example for 3 seconds, the color was black. At this time, the reflectance at 550 nm was as shown in the following table.

DESCRIPTION OF SYMBOLS 1 Display electrode 2 Counter electrode 3 Electrolyte 4 Electrochemical compound 4a Electromic composition 5 Display layer 6 White reflective layer 10 Display element 20 Display element 30 Light control element

JP 2006-267829 A JP 2011-102287 A

Claims (7)

An electrochromic compound represented by the following general formula (I):

(In the formula, at least two of X ₁ , X ₂ and X ₃ in the general formula (I) have the structure of the general formula (II). When the structure of the general formula (II) is two, the remaining Any one of X ₁ , X ₂ , and X _{3 is} an aliphatic hydrocarbon group, an aromatic hydrocarbon group, or a hydrogen atom that may have a functional group, Y _{1 to} Y _8. Each independently represents a hydrogen atom or a monovalent group, which may have a substituent, R represents a monovalent group that may have a functional group, valent group rather it may also have a substituent, .m having at least one directly or indirectly bondable functional group relative to the hydroxyl group of R is either 0 to 3 .A ^-. the _Y 1 _{to Y} 8 in the general formula (II) entering the _{X 1,} X 2, _{X 3} of a monovalent anion general formula (I), m, ^- of the structure may be different independent). _{2. The} electrochromic compound according to claim ₁ , wherein _two of X ₁ , X ₂ , and X _{3 in} the general formula (I) have the structure of the general formula (II). X in general formula (I) ₁ ~ X ₃ 3. The electrochromic compound according to claim 1, wherein at least one of them has a functional group capable of binding directly or indirectly to a hydroxyl group. The functional group that can be directly or indirectly bonded to a hydroxyl group is a group selected from a phosphonic acid group, a phosphoric acid group, a carboxylic acid group, a silyl group, and a silanol group. 4. The electrochromic compound according to any one of 3. An electrochromic composition comprising the electrochromic compound according to any one of claims 1 to 4 and a conductive or semiconducting nanostructure bonded or adsorbed. A display electrode, a counter electrode provided to face the display electrode at a distance from each other, and an electrolyte disposed between the two electrodes, the surface of the display electrode having at least any one of claims 1 to 4 A display element comprising a display layer comprising the electrochromic compound according to claim 1 or the electrochromic compound and the electrochromic composition according to claim 5. A display electrode; a counter electrode provided opposite to the display electrode at an interval; and an electrolyte disposed between the electrodes, and at least an electrochromic compound or an electrochromic composition on the surface of the display electrode In an element having a structure, the electrochromic compound or the electrochromic composition is the electrochromic compound according to any one of claims 1 to 4 or the electrochromic composition according to claim 5, wherein the display electrode and the counter electrode A light control device, wherein the electrolyte is transparent.

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