JP2015101691A - Electrochromic compound and display element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrochromic material that facilitates color adjustment in color development, and a display element using the electrochromic material.SOLUTION: An electrochromic material is a polymer having a plurality of kinds of chromophores coupled through a coupling group in a main chain.

Description

  The present invention relates to an electrochromic compound that allows easy color adjustment during color development, and a display device using the electrochromic compound.

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
Of these, the white reflectance / contrast ratio equivalent to that of paper and the demand for color display are particularly high as characteristics relating to display quality.

Until now, 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.
However, it is very difficult for any of the above methods to perform multicolor display while ensuring white reflectance / contrast ratio.

In general, a color filter is provided to perform multicolor display. However, when a color filter is provided, the color filter itself absorbs light and the reflectance decreases.
Furthermore, since the color filter divides one pixel into red (R), green (G), and blue (B), the reflectance of the display device is lowered, and the contrast ratio is lowered accordingly.
When the white reflectance / contrast ratio is significantly reduced, the visibility is very poor and it is difficult to use as electronic paper.

Patent Documents 1 and 2 disclose a reflective color display medium in which a color filter is formed on an electrophoretic element. However, it is clear that good image quality cannot be obtained even when a color filter is formed on a display medium using electrophoresis with low white reflectance and low contrast ratio.

Furthermore, Patent Documents 3 and 4 disclose electrophoretic elements that perform colorization by moving particles colored in a plurality of colors. However, in principle, these methods are expensive. The above problem of simultaneously satisfying the white reflectance and the high contrast ratio cannot be solved.

On the other hand, as a promising technique for realizing a reflective display device without providing the color filter as described above, there is a method using an electrochromic phenomenon. The electrochromic phenomenon is a phenomenon in which a redox reaction occurs reversibly and a color changes reversibly by applying a voltage.
An electrochromic display device is a display device that utilizes the coloring / decoloring of an electrochromic compound that causes the electrochromic phenomenon (hereinafter also referred to as color development / decoloration).

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.
However, the electrochromic display device has a drawback that the response speed of color development / decoloration is slow because of the principle of performing color development / decoloration using an oxidation-reduction reaction.

Patent Document 5 describes an example in which an electrochromic compound is fixed in the vicinity of an electrode to improve the response speed of color development and decoloration. According to the description in Patent Document 5, conventionally, the time required for color development / decoloration was about several tens of seconds, but both the color development time from colorless to blue and the color elimination time from blue to colorless have been improved to about 1 second. It is said that
However, this is not sufficient, and in the research and development of electrochromic display devices, it is necessary to further improve the response speed of color development and decoloration.

An electrochromic display device is expected as a multicolor display device because it can generate various colors depending on the structure of the electrochromic compound. In particular, since a colorless state and a color development state are reversibly changed, a stacked multi-color configuration can be realized.
In color display with a stacked structure, it is not necessary to divide one pixel into red (R), green (G), and blue (B) as in the prior art, so the reflectance and contrast ratio of the display device do not decrease. .

There are some known examples of such a multicolor display device using an electrochromic display device.
For example, Patent Document 6 discloses a multicolor display device using an electrochromic compound in which fine particles of a plurality of types of electrochromic compounds are stacked. Specifically, an example of a multicolor display device is described in which a plurality of electrochromic compounds, which are polymer compounds having a plurality of functional functional groups with different voltages exhibiting color development, are stacked to form a multicolor display electrochromic compound. Yes.

  Further, Patent Document 7 discloses a display device in which a multi-layer electrochromic layer is formed on an electrode, and multiple colors are developed by using a difference in voltage value or current value necessary for the color development. Specifically, a multi-color display device having a display layer formed by laminating or mixing a plurality of electrochromic compounds that develop different colors and have different threshold voltages for color development and different charge amounts necessary for color development. An example is given.

  Furthermore, Patent Document 8 describes an example of a multicolor display device in which a plurality of structural units each having an electrochromic layer and an electrolyte sandwiched between a pair of transparent electrodes are stacked. Further, Patent Document 9 describes an example of a multicolor display device that forms a passive matrix panel and an active matrix panel using the structural units described in Patent Document 8 and corresponds to RGB three colors.

  However, the styryl dyes used in the electrochromic display devices described in Patent Documents 5 and 6 and Patent Document 7 produce good yellow, magenta, and cyan colors, but are stable in color development and repeated durability. There's a problem.

  In addition, the viologen-based organic electrochromic compounds exemplified in Patent Documents 8, 9, and 10 are compounds having high stability and high durability. It does not develop the three primary colors yellow, magenta, and cyan, which are necessary for full color by the law.

  Patent Document 11 reports a phthalic acid-based compound that develops yellow, magenta, and cyan. However, there is a problem that phthalic acid compounds have poor memory performance.

  In this way, satisfactory electrochromic compounds for realizing full-color electronic paper do not yet exist, and the appearance of materials excellent in color tone, durability, and stability is desired.

Conventionally, the color developed by an electrochromic display device is a color developed by charge injection into an electrochromic compound, so it is necessary to change the electrochromic compound itself in order to develop a desired color. In order to make fine adjustments, the molecular structure of the electrochromic molecule itself had to be changed.
The present invention has been made in view of the above-described problems in the prior art, and an object thereof is to provide an electrochromic material in which color adjustment of color development is easy, and a display element using the electrochromic material.

  As a result of intensive studies, the present inventors have found that the above problems can be solved by a polymer obtained by copolymerizing a plurality of electrochromic dyes, and have completed the present invention.

That is, the said subject is solved by following (1)-(4) of this invention.
(1) An electrochromic material, which is a polymer having a plurality of types of chromophores bonded to each other through a linking group in the main chain.
(2) The electro described in the above item (1), which is a polymer composed of structural units represented by the following general formula (I), wherein A is a plurality of types of units different in the polymer. Chromic materials;

（一般式（Ｉ）中、Ｒ^１及びＲ^２はそれぞれ独立に水素原子または一価の置換基であり、ａ及びｂはそれぞれ独立に０から４の整数を表し、Ｒは二価の置換基を表し、Ａは単結合または共役ユニットから選択される二価の置換基を表す。）。
（３）下記一般式（ＩＩ）または（ＩＩＩ）で表される重合体であることを特徴とする前記（１）項または前記（２）項に記載のエレクトロクロミック材料；

(In the general formula (I), R ¹ and R ² are each independently a hydrogen atom or a monovalent substituent, a and b are each independently an integer of 0 to 4, and R is a divalent substituent. A represents a divalent substituent selected from a single bond or a conjugated unit.
(3) The electrochromic material as described in (1) or (2) above, which is a polymer represented by the following general formula (II) or (III);

（一般式（ＩＩ）、及び一般式（ＩＩＩ）中、Ｒは二価の置換基を表し、Ａ^１からＡ^３はそれぞれ異なる、単結合または共役ユニットから選択される二価の置換基を表し、ｘ、ｙ、ｚはそれぞれ繰り返し単位の組成比を表す。）。
（４）表示電極と、該表示電極に対向した状態で間隔をおいて設けられた対向電極と、前記表示電極と前記対向電極との間に配置された電解質とを備え、
前記表示電極における前記対向電極との対向面に表示層を有する表示素子であって、
前記表示層は、少なくとも前記（１）項乃至（３）項のいずれかに記載のエレクトロクロミック材料を含むことを特徴とする表示素子。

(In general formula (II) and general formula (III), R represents a divalent substituent, and A ¹ to A ³ each represent a divalent substituent selected from different single bonds or conjugated units. , X, y, and z each represent the composition ratio of the repeating unit.
(4) comprising a display electrode, a counter electrode provided at a distance in opposition to the display electrode, and an electrolyte disposed between the display electrode and the counter electrode,
A display element having a display layer on a surface of the display electrode facing the counter electrode,
The display element includes at least the electrochromic material according to any one of the items (1) to (3).

  As will be understood from the following detailed and specific description, according to the present invention, it is possible to provide an electrochromic compound in which the color adjustment of color development is easy, and a display element using the electrochromic compound.

It is the schematic which shows the structural example of the general display element using the electrochromic compound which concerns on this invention. 6 is a graph showing absorption spectra at the time of coloring and decoloring of the electrochromic display element of Example 3.

<Electrochromic materials>
The electronic material of the present invention will be described in detail.
The electrochromic polymer according to the present invention is a polymer having a plurality of types of chromophores via a linking group in the main chain.
Specifically, it has a structural unit represented by the following general formula (I), and has different types of units as the unit represented by A.

（一般式（Ｉ）中、Ｒ^１及びＲ^２はそれぞれ独立に水素原子または一価の置換基であり、ａ及びｂはそれぞれ独立に０から４の整数を表し、Ｒは二価の置換基を表し、Ａは単結合または共役ユニットから選択される二価の置換基を表す。）

(In the general formula (I), R ¹ and R ² are each independently a hydrogen atom or a monovalent substituent, a and b are each independently an integer of 0 to 4, and R is a divalent substituent. And A represents a divalent substituent selected from a single bond or a conjugated unit.)

Specific examples of R ¹ and R ² in the general formula (I) include hydrogen atom, halogen atom, substituted or unsubstituted alkyl group, substituted or unsubstituted alkoxy group, substituted or unsubstituted aryl group, substituted or Examples thereof include an unsubstituted aryloxy group, a substituted or unsubstituted alkylthio group, and a substituted or unsubstituted arylthio group.

  Specific examples of R in the general formula (I) include an alkylene group, an alkenylene group, an alkynylene group, a polyoxyalkylene group, an arylene group, or a divalent group composed of these, and these are substituted. It may have a group.

A in the general formula (I) is a single bond or a conjugated unit, and the conjugated unit may have a substituent.
Examples of the conjugated unit include a halogen atom, a hydroxyl group, a nitro group, a cyano group, a carboxyl group, an optionally substituted alkoxycarbonyl group, an optionally substituted aryloxycarbonyl group, and a substituted group. An alkylcarbonyl group which may have a group, an arylcarbonyl group which may have a substituent, an amide group, a monoalkylaminocarbonyl group which may have a substituent, and a substituent. May be a dialkylaminocarbonyl group, a monoarylaminocarbonyl group which may have a substituent, a diarylaminocarbonyl group which may have a substituent, a sulfonic acid group, an alkoxy which may have a substituent Sulfonyl group, aryloxysulfonyl group which may have a substituent, alkyls which may have a substituent A sulfonyl group, an optionally substituted arylsulfonyl group, a sulfonamide group, an optionally substituted monoalkylaminosulfonyl group, an optionally substituted dialkylaminosulfonyl group, a substituted group A monoarylaminosulfonyl group which may have a group, a diarylaminosulfonyl group which may have a substituent, an amino group, a monoalkylamino group which may have a substituent, and a substituent A dialkylamino group which may have a substituent, an alkyl group which may have a substituent, an alkenyl group which may have a substituent, an alkynyl group which may have a substituent, and a substituent. An aryl group which may have a substituent, an alkoxy group which may have a substituent, an aryloxy group which may have a substituent, an alkylthio group which may have a substituent, Good arylthio group which may have a group, and heterocyclic group which may have a substituent.

The polymer of the present invention represented by the general formula (I) has two pyridinium structures in one repeating unit.
Since the pyridinium structure is a monovalent cation, a counter anion exists in the polymer of the present invention represented by the general formula (I). The counter anion is not particularly limited as long as it is stably paired with a cation moiety having a pyridinium structure. Examples of the anion include Br ion, Cl ion, ClO ₄ ion, PF ₆ ion, and BF. ₄ ion, _CF 3 SO ₃ ion, and the like.

  The electrochromic polymer represented by the general formula (I) is a copolymer having a plurality of dye skeletons in one molecule. By changing the chromophore to be introduced and the abundance ratio of the chromophore, an electrochromic reaction is performed. This makes it possible to easily control the color to be developed.

The polymer represented by the general formula (I) has a plurality of different units as the unit represented by A. Specifically, the polymer is represented by the following general formula (II) or general formula (III). A polymer is preferred.

（一般式（ＩＩ）、一般式（ＩＩＩ）中、Ｒは、二価の置換基を表し、Ａ^１からＡ^３はそれぞれ異なる、単結合または共役ユニットから選択される二価の置換基を表し、Ｘ、Ｙ、Ｚはそれぞれ繰り返し単位の組成比を表す。）

(In General Formula (II) and General Formula (III), R represents a divalent substituent, and A ¹ to A ³ each represent a different divalent substituent selected from a single bond or a conjugated unit. , X, Y, and Z each represent a composition ratio of repeating units.)

As shown in the general formula (II), by differentiating the structures of A ¹ and A ² and arranging a plurality of electrochromic dyes in the polymer, each dye can be colored, The color tone can be controlled by changing the composition ratio of each repeating unit.
Furthermore, as shown in the general formula (III), it is possible to further increase the type of the A portion.

Examples of R in the general formula (II) and general formula (III) include the same ones as R in the general formula (I). A ^{1 to} A ³ may be the same as those in the general formula (I). It may either be similar to those listed a, a ¹ ~A ³ are different from each other.

Further, the electrochromic polymer according to the present invention has a large molecular weight, has a plurality of different chromophores, and has low crystallinity, so that a stable thin film can be formed on the electrode surface.
The molecular weight of the electrochromic polymer according to the present invention is preferably 5000 or more.

<Method for producing polymer>
Next, the manufacturing method of the electrochromic polymer which concerns on this invention is demonstrated.
The electrochromic polymer according to the present invention includes, for example, a bipyridine compound having a conjugated unit represented by A ¹ between two pyridine rings and an A ² between two pyridine rings as shown in the following reaction formula. a bipyridine compound having conjugated units represented in, can be produced by linking at R, including R number of moles same amount of combined monomer containing the a ² and monomers containing the a ¹ It can be synthesized by using a monomer.

前記Ｒを含むモノマー中、Ｘはハロゲン、トリフルオロメタンスルホニルオキシ基、メタンスルホニルオキシ基、トルエンスルホニルオキシ基などの脱離基を表し、これらは反応の進行により生成したピリジニウムカチオンの対アニオンとして存在する。

In the monomer containing R, X represents a leaving group such as halogen, trifluoromethanesulfonyloxy group, methanesulfonyloxy group, and toluenesulfonyloxy group, and these exist as counter anions of the pyridinium cation generated by the progress of the reaction. .

  The reaction proceeds by stirring in a solvent such as DMF, nitromethane, and toluene, usually at a temperature of about 100 ° C.

<Display element>
Next, the display element according to the present invention will be described.
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), a display element of the present invention includes a display electrode, a counter electrode provided to face the display electrode at an interval, and both electrodes (display electrode, counter electrode). And a display layer including at least the electrochromic compound of the present invention on the surface of the display electrode on the counter electrode side (the surface facing the counter electrode).
In the display element of FIG. 1A, the display layer is formed on the surface of the display electrode on the counter electrode side using the electrochromic compound of the present invention.
As the formation method, any method such as dipping, dipping, spin coating, printing, and ink jet may be used.

In addition, as shown in FIG. 1B, it is possible to have a solution configuration in which an electrolyte is dissolved in a solvent, and it is also possible to dissolve an electrochromic compound in the solution.
In this case, the electrochromic compound develops and discolors only by the oxidation-reduction reaction on the electrode surface. That is, in the solution containing the electrochromic compound, the surface of the display electrode facing the counter electrode functions as a display layer.

Further, as shown in FIG. 1C, a configuration having a white reflective layer made of white particles or the like and scattering light between the electrochromic display layer and the counter electrode is also possible.
In this case, it is possible to display an image colored on a white background by an electrochromic reaction.

Next, materials used for the electrochromic display element according to the embodiment of the present invention will be described.
It is desirable to use a transparent conductive substrate as the display electrode. The transparent conductive substrate is preferably glass or a plastic film coated with a transparent conductive thin film. If a plastic film is used, a lightweight and flexible display element can be produced.

  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.

Examples of the transparent conductive material include indium oxide doped with tin (hereinafter referred to as ITO), tin oxide doped with fluorine (hereinafter referred to as FTO), and tin oxide doped with antimony (hereinafter referred to as ATO). An inorganic material can be used, but in particular, an indium oxide (hereinafter referred to as In oxide), a tin oxide (hereinafter referred to as Sn oxide), or a zinc oxide (hereinafter referred to as Zn oxide). It is preferable that it is an inorganic material containing any one.
In oxides, Sn oxides, and Zn oxides are materials that can be easily formed by sputtering, and are materials that can provide good transparency and electrical conductivity. Particularly preferable materials are InSnO, GaZnO, SnO, In ₂ O ₃ and ZnO.

As the counter electrode, a transparent conductive film such as ITO, FTO, or zinc oxide, or a conductive metal film such as zinc or platinum, or carbon is used. The counter electrode is also generally formed on the substrate. The counter electrode substrate is also preferably glass or plastic film.
When a metal plate such as zinc is used as the counter electrode, the counter electrode also serves as the substrate.

Further, when the material of the counter electrode 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 develops color by oxidation, it causes a reduction reaction. When the electrochromic composition develops color by reduction, a material that causes oxidation reaction is used as a counter electrode in the display layer containing the electrochromic composition. The reaction of color development and decoloration becomes more stable.

As the electrolyte, generally, an electrolyte obtained by dissolving a supporting salt in a solvent is 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.
Specifically, 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, and the like 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 between the display electrode and the counter electrode as shown in FIG.
For the white reflective layer, the simplest production method is to disperse white pigment fine particles in a resin and apply it on the counter electrode.

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 element, 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.

  Hereinafter, although the electrochromic polymer of the present invention and the display element using the same will be described in Examples, the present invention is not limited to the following Examples.

[Example 1]
(Synthesis of electrochromic polymer (P-1))
The electrochromic compound (P-1) was synthesized according to the following scheme.

５０ｍｌフラスコにモノマー（ｍ−１）０．０７９ｇ（０．２６６ｍｍｏｌ）、モノマー（ｍ−２）０．１００ｇ（０．２６６ｍｍｏｌ）、モノマー（ｍ−３）０．１９２ｇ（０．５３２ｍｍｏｌ）を入れ、アルゴン置換した。脱水ＤＭＦ ５ｍｌを加え、１００℃で８時間撹拌した。
室温に戻した後、反応溶液を２−プロパノールに滴下し、析出した固体を濾取した。得られた固体を酢酸エチルで洗浄した後、真空乾燥し、目的の共重合体（Ｐ−１）を０．３７１ｇ得た。収率７９％。

Into a 50 ml flask was charged 0.079 g (0.266 mmol) of monomer (m-1), 0.100 g (0.266 mmol) of monomer (m-2), 0.192 g (0.532 mmol) of monomer (m-3), Argon substitution was performed. 5 ml of dehydrated DMF was added and stirred at 100 ° C. for 8 hours.
After returning to room temperature, the reaction solution was added dropwise to 2-propanol, and the precipitated solid was collected by filtration. The obtained solid was washed with ethyl acetate and then vacuum-dried to obtain 0.371 g of the desired copolymer (P-1). Yield 79%.

The data of a copolymer (P-1) infrared absorption spectrum are shown.
IR (NaCl) ν / cm -1; 3391, 3035, 2927, 2466, 1633, 1597, 1556, 1532, 1513, 1493, 1464, 1418, 1227, 1163, 1027, 841, 822, 751.

[Example 2]
(Production of electrochromic display element)
First, a 30 mm × 30 mm glass substrate was prepared, and an ITO film was formed in a 16 mm × 23 mm region on the upper surface by a sputtering method so as to have a thickness of about 100 nm, thereby forming a display electrode. The sheet resistance between the electrode ends of this display electrode was measured and found to be about 200Ω.
Next, the 2,2,3,3-tetrafluoropropanol solution of the electrochromic polymer (P-1) synthesized in Example 1 was cast and dried to form an electrochromic display layer on the ITO film. did.

  The display substrate and the counter substrate with ITO 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 a display element using an electrochromic polymer (P-1).

[Example 3]
(Decoloration test of the produced electrochromic display element)
The electrochromic display element produced in Example 2 was subjected to comparative evaluation of color development and decoloration.
The negative electrode was connected to the display electrode of the display element and the positive electrode was connected to the counter electrode, and the absorption spectrum accompanying voltage application from 0 V to −2 V was measured. The results are shown in FIG.
With application of voltage, a sharp absorption band near 550 nm derived from an electrochromic reaction of a pyridinium unit containing N-phenylpyrrole, 600 to 800 nm and 400 derived from an electrochromic reaction of a pyridinium unit containing diphenyloxadiazole A broad absorption band from 1 to 500 nm appeared at the same time.

[Example 4]
(Synthesis of electrochromic polymer (P-2))
An electrochromic compound (P-2) was synthesized according to the following scheme.

５０ｍｌフラスコに、モノマー（ｍ−２）３６．２ｍｇ（９６．２μｍｏｌ）、モノマー（ｍ−４）２２．４ｍｇ（９６．２μｍｏｌ）、モノマー（ｍ−５）４７．６ｍｇ（９６．２μｍｏｌ）を入れ、アルゴン置換した。
脱水ＤＭＦ ８ｍｌ及びトルエン２ｍｌを加え、１００℃で１０分撹拌した。この溶液に、モノマー（ｍ−６） ９４．７ｍｇ （２８８．７μｍｏｌ）を引き続き１００℃で２７時間撹拌した。
室温に戻した後、反応溶液を２−プロパノールに滴下し、析出した固体を濾取した。得られた固体を酢酸エチルで洗浄した後、真空乾燥し、目的の共重合体（Ｐ−２）を１９０ｍｇ得た。収率９５％。

Into a 50 ml flask was placed 36.2 mg (96.2 μmol) of monomer (m-2), 22.4 mg (96.2 μmol) of monomer (m-4), and 47.6 mg (96.2 μmol) of monomer (m-5). And replaced with argon.
8 ml of dehydrated DMF and 2 ml of toluene were added and stirred at 100 ° C. for 10 minutes. To this solution, 94.7 mg (288.7 μmol) of monomer (m-6) was subsequently stirred at 100 ° C. for 27 hours.
After returning to room temperature, the reaction solution was added dropwise to 2-propanol, and the precipitated solid was collected by filtration. The obtained solid was washed with ethyl acetate and then vacuum-dried to obtain 190 mg of the target copolymer (P-2). Yield 95%.

The data of a copolymer (P-2) infrared absorption spectrum are shown.
IR (NaCl) ν / cm @ -1; 2925, 2863, 1712, 1634, 1598, 1559, 1489, 1463, 1409, 1292, 1247, 1176, 1010, 829, 750, 666.

JP 2003-161964 A JP 2004-361514 A Japanese translation of PCT publication No. 2004-520621 Special table 2004-536344 gazette Special table 2001-510590 gazette JP 2003-121883 A JP 2006-106669 A JP 2003-270671 A JP 2004-151265 A JP 2008-122578 A JP 2006-71767 A

Claims (4)

An electrochromic material which is a polymer having a plurality of kinds of chromophores bonded to each other through a linking group in the main chain. 2. The electrochromic material according to claim 1, wherein the electrochromic material is a polymer composed of structural units represented by the following general formula (I), wherein A is a plurality of different units in the polymer.

(In the general formula (I), R ¹ and R ² are each independently a hydrogen atom or a monovalent substituent, a and b are each independently an integer of 0 to 4, and R is a divalent substituent. And A represents a divalent substituent selected from a single bond or a conjugated unit.) The electrochromic material according to claim 1 or 2, which is a polymer represented by the following general formula (II) or (III).

(In general formula (II) and general formula (III), R represents a divalent substituent, and A ¹ to A ³ each represent a divalent substituent selected from different single bonds or conjugated units. , X, y, and z each represent the composition ratio of the repeating unit.) A display electrode, a counter electrode provided at a distance in opposition to the display electrode, and an electrolyte disposed between the display electrode and the counter electrode,
A display element having a display layer on a surface of the display electrode facing the counter electrode,
The display element comprising the electrochromic material according to claim 1 at least.

Images