CN106886113B

CN106886113B - Electrochromic display element

Info

Publication number: CN106886113B
Application number: CN201611152087.XA
Authority: CN
Inventors: 篠田雅人; 山本谕; 匂坂俊也; 后藤大辅; 堀内保; 高桥裕幸; 金子史育; 井上满美子; 八代彻
Original assignee: Ricoh Co Ltd
Current assignee: Ricoh Co Ltd
Priority date: 2015-12-15
Filing date: 2016-12-14
Publication date: 2020-08-25
Anticipated expiration: 2036-12-14
Also published as: JP2017111434A; CN106886113A; JP6870288B2

Abstract

The present invention relates to an electrochromic display element. The present invention addresses the problem of providing an electrochromic display element which can be driven at low voltage using an oxidative color-developing electrochromic display compound. An electrochromic display element of the present invention has a first electrode, a second electrode, and an electrolyte between the first electrode and the second electrode, and has a layer containing an oxidative color-developing electrochromic display compound on the first electrode, and a layer containing a specific compound represented by the following chemical formula (1) on the second electrode: chemical formula (1)

In the above formula, R₁～R₅Each independently represents a hydrogen atom, a halogen atom, a monovalent organic group, R₁～R₅At least one of which has a functional group capable of bonding directly or indirectly to a hydroxyl group.

Description

Electrochromic display element

Technical Field

The present invention relates to an electrochromic display element.

Background

A phenomenon in which a reversible redox reaction occurs and a color reversibly changes by application of a voltage is called electrochromism. Generally, in an electrochromic display element in which an electrolyte layer capable of conducting ions is provided between two opposed electrodes, a redox reaction is caused. When a reduction reaction occurs in the vicinity of one of the two electrodes opposed to each other, an oxidation reaction, which is a reverse reaction, occurs in the vicinity of the other electrode. In such an electrochromic display element, when a transparent display device is to be obtained or when a device having a laminated structure of three coloring layers of cyan (C), magenta (C), and yellow (Y) is to be constructed, it is important to form the electrochromic display element from a material having a colorless transparent state.

Examples of such a material include viologen compounds which exhibit an electrochromic phenomenon and are transparent in a neutral state and emit color in a reduced state. Further, as an oxidation color-developing electrochromic material which is transparent in a neutral state and develops color in an oxidized state, a triarylamine compound and the like have been reported (see non-patent documents 1 to 2).

On the other hand, the present applicant proposed an electrochromic display element using a triarylamine compound which can stably operate and has excellent light resistance in a conventional patent application (japanese patent application 2015-134017). However, a technique relating to the reduction side of the counter electrode, particularly a technique enabling driving at a low voltage using an oxidative color-developing electrochromic material, has not been studied.

In another conventional patent application (japanese patent application 2014-171858), an electrochromic display element having a high contrast is proposed in which a combination of a reduced-side viologen and an oxidized-side triarylamine is used. However, since the reducing side and the oxidizing side develop color together, there is a problem that it is difficult to obtain color only on the oxidizing side.

As described above, no known documents and known techniques have been found which disclose a technique for improving the color-changing display characteristics, particularly driving at a low voltage, by using an oxidative color-developing electrochromic material.

[ Prior art documents ]

[ non-patent literature ]

[ non-patent document 1 ] chem.mater.2006, 18, 5823-.

Non-patent document 2 org. electron.2014, 15, 428-.

Disclosure of Invention

An object of the present invention is to solve the above-described various problems of the conventional art and to provide an electrochromic display element which can be driven at a low voltage using an oxidative color-developing electrochromic display compound.

The present inventors have continued their studies to solve the above-described problems, and as a result, have found that an electrochromic display element which can be driven at a low voltage can be obtained by providing a layer containing a compound having a phenol structure, particularly a hindered phenol structure, on a second electrode.

That is, the above problem is solved by the invention of the following 1).

1) An electrochromic display element having a first electrode, a second electrode, and an electrolyte between the first electrode and the second electrode, characterized in that:

the first electrode has a layer containing an oxidative color-developing electrochromic display compound, and the second electrode has a layer containing a specific compound represented by the following chemical formula (1):

chemical formula (1)

In the present invention, the "layer containing an oxidative color-developing electrochromic display compound" is also referred to as a "first layer", and the "layer containing a specific compound represented by chemical formula (1)" is also referred to as a "second layer".

The following describes the effects of the present invention:

according to the present invention, an electrochromic display element which can be driven at a low voltage using an oxidative color-developing electrochromic display compound can be provided. Further, since this element does not absorb light in the visible region and does not exhibit reductive color development, it is possible to obtain a color of only the used oxidative color-developing electrochromic display compound.

Drawings

Fig. 1 is a schematic view showing an example of an electrochromic display device according to the present invention.

Fig. 2 is an IV characteristic diagram in CV measurement of the element of example 1.

Fig. 3 is a graph of the CV and TV characteristics in the transmittance measurement of the element of example 1.

Fig. 4 is an IV characteristic diagram in CV measurement of the element of comparative example 1.

Fig. 5 is a graph showing CV and TV characteristics in transmittance measurement of the element of comparative example 1.

Fig. 6 is an IV characteristic diagram in CV measurement of the element of comparative example 2.

Detailed Description

The present invention 1) will be described in detail below, but embodiments thereof also include the following 2) to 7).

2) The electrochromic display element according to claim 1), wherein the monovalent organic group in the specific compound is an organic group selected from an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a heteroaryl group, an alkoxy group, an aryloxy group, and a heteroaryloxy group.

3) The electrochromic display element according to 1) or 2), wherein R in the above-mentioned specific compound₃Containing a functional group capable of bonding directly or indirectly to a hydroxyl group.

4) The electrochromic display element according to any one of claims 1) to 3), wherein the functional group capable of bonding directly or indirectly to a hydroxyl group is a functional group selected from a phosphonic acid group, a phosphoric acid group, a carboxylic acid group, a sulfonyl group, a silyl group, and a silanol group.

5) The electrochromic display element according to any one of 1) to 4), wherein the functional group capable of bonding directly or indirectly to a hydroxyl group contains an alkyl group, an aryl group, or an aryl group substituted with an alkyl group.

6) The electrochromic display element according to any one of 1) to 5), wherein the specific compound is bonded to or adsorbed on a conductive or semiconductive nanostructure provided on the second electrode.

7) The electrochromic display element according to any one of claims 1) to 5), wherein the layer containing the specific compound represented by the above chemical formula (1) is a counter electrode layer provided on the second electrode.

(electrochromic display element)

An electrochromic (electrochromic) element of the present invention has a first electrode, a second electrode, and an electrolyte between the first electrode and the second electrode, and further has other components as necessary.

The first electrode has a layer containing an oxidative color-developing electrochromic display compound, and the second electrode has a layer containing a specific compound represented by the following chemical formula (1).

Chemical formula (1)

(in the above formula, R₁～R₅Each independently represents a hydrogen atom, a halogen atom, a monovalent organic group, R₁～R₅At least one of which has a functional group capable of bonding directly or indirectly to a hydroxyl group).

< specific Compound represented by the formula (1) >)

The specific compound is present on the second electrode, but may be present in a state of being bonded to, adsorbed to, or mixed with a counter electrode layer or the like provided on the second electrode.

R₁～R₅Each represents a hydrogen atom, a halogen atom, or a monovalent organic group, and may be the same or different.

The monovalent organic groups are each independently a hydroxyl group, a nitro group, a cyano group, a carboxyl group, an alkoxycarbonyl group which may have a substituent, an aryloxycarbonyl group which may have a substituent, an alkylcarbonyl group which may have a substituent, an allylcarbonyl group which may have a substituent, an amide group, a monoalkylaminocarbonyl group which may have a substituent, a dialkylaminocarbonyl group which may have a substituent, a monoarylaminocarbonyl group which may have a substituent, a diarylaminocarbonyl group which may have a substituent, a sulfonic acid group, an alkoxysulfonyl group which may have a substituent, an aryloxysulfonyl group which may have a substituent, an alkylsulfonyl group which may have a substituent, an arylsulfonyl group which may have a substituent, a sulfonamido group, a monoalkylaminosulfonyl group which may have a substituent, a dialkylaminosulfonyl group which may have a substituent, a monoarylaminosulfonyl group which may have a substituent, a diarylaminosulfonyl group which may have a substituent, an amino group, a monoalkylamino group which may have a substituent, a dialkylamino group which may have a substituent, an alkyl group which may have a substituent, an alkenyl group which may have a substituent, an alkynyl group which may have a substituent, an aryl group which may have a substituent, an alkoxy group which may have a substituent, an aryloxy group which may have a substituent, an alkylthio group which may have a substituent, an arylthio group which may have a substituent, a heterocyclic group which may have a substituent, and the like.

Among them, particularly preferred are alkyl groups, alkoxy groups, hydrogen atoms, aryl groups, aryloxy groups, heteroaryl groups, heteroaryloxy groups, halogen groups, alkenyl groups, alkynyl groups from the viewpoints of motion stability and light resistance.

Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom and the like.

Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, and a butyl group.

Examples of the aryl group include phenyl and naphthyl.

Examples of the aralkyl group include a benzyl group, a phenethyl group, a naphthylmethyl group and the like.

Examples of the alkoxy group include a methoxy group, an ethoxy group, and a propoxy group.

Examples of the aryloxy group include a phenoxy group, a 1-naphthoxy group, a 2-naphthoxy group, a 4-methoxyphenoxy group, and a 4-methylphenoxy group.

Examples of the above-mentioned polycyclic group include carbazole, dibenzofuran, dibenzothiophene, oxadiazolone, thiadiazole and the like.

Examples of the substituent to which the substituent is further substituted include a halogen atom, a nitro group, a cyano group, an alkyl group such as a methyl group or an ethyl group, an alkoxy group such as a methoxy group or an ethoxy group, an aryloxy group such as a phenoxy group, an aryl group such as a phenyl group or a naphthyl group, an aralkyl group such as a benzyl group or a phenethyl group, and the like.

Examples of the functional group to which the hydroxyl group can be directly or indirectly bonded include a phosphonic acid group, a phosphoric acid group, a carboxylic acid group, a sulfonyl group, a silyl group, and a silanol group, and the following compounds are preferable.

-PO(OH)₂-Si(OH)₃-SiCl₃-CH₂-PO(OH)₂

-OPO(OH)₂-Si(OEt)₃-PO(OH)₂-(CH₂)₂-PO(OH)₂

-COOH -CH₂-COOH -CH₂-PO(OH)(OEt)

The functional group to which the above-mentioned hydroxyl group can be directly or indirectly bonded may have a group containing an alkyl group, an aryl group, or an aryl group substituted with an alkyl group, or the like.

Examples of the aryl group include phenyl and naphthyl.

Specific examples of the specific compounds are shown below, but the specific compounds are not limited to these.

< oxidative color-developing electrochromic display Compound >

In the present invention, the first electrode has a layer containing an oxidative color-developing electrochromic display compound. Examples of the oxidative color-developing electrochromic display compound that can be used include azobenzene-based, tetrathiafulvalene-based, triphenylmethane-based, triphenylamine-based, and white dyes, and among them, a compound having a triarylamine skeleton is preferable.

As the compound having a triarylamine skeleton, compounds represented by the following chemical formulae 2 to 4 are preferable.

Chemical formula (2)

Chemical formula (3)

Chemical formula (4)

R in chemical formula 2-4₂₇～R₈₉The monovalent organic groups may be the same or different.

As the above-mentioned monovalent organic group, there may be mentioned R in the above-mentioned relation to the formula (1)₁～R₅The monovalent organic group in (1) is the same as the compound exemplified on pages 4 to 5 of the present specification.

The form of the layer containing the oxidative color-developing electrochromic display compound is not particularly limited as long as it has compatibility with an electrolyte. For example, the polymer may be present in a low molecular state on the first electrode, or may be present in a cured state from a photocrosslinkable group such as acrylate or methacrylate. The particles may be present in a state of being bonded or adsorbed to the supporting particles or the conductive particles.

The average thickness of the layer containing the oxidative color-developing electrochromic display compound is preferably 0.1 to 30 μm, more preferably 0.4 to 10 μm.

< first electrode and second electrode >

The material of the first electrode and the second electrode is not particularly limited as long as it is a transparent material having conductivity, and may be appropriately selected according to the purpose. Examples thereof include tin-doped indium oxide (ITO), fluorine-doped tin oxide (FTO), antimony-doped tin oxide (ATO), and zinc oxideAnd the like. Among them, InSnO, GaZnO, SnO and In are preferable₂O₃，ZnO。

Further, a carbon nanotube having transparency, or an electrode in which conductivity is improved while transparency is maintained by forming a fine network of another highly conductive non-transmissive material such as Au, Ag, Pt, or Cu may be used.

The thicknesses of the first electrode and the second electrode are adjusted to obtain resistance values necessary for the oxidation-reduction reaction of the electrochromic layer. The electrochromic layer herein means a "layer containing an oxidative color-developing electrochromic display compound" (first layer).

The thickness of each of the first electrode and the second electrode when ITO is used is preferably 50 to 500nm, for example.

As a method for manufacturing the first electrode and the second electrode, a coating method, a printing method, a vacuum deposition method, a sputtering method, an ion plating method, or the like can be used.

In the above coating method, as long as the respective materials of the first electrode and the second electrode can be coated, there is no particular limitation, and for example, a spin coating method, a casting method, a micro gravure coating method, a bar coating method, a roll coating method, a wire bar coating method, a draw coating method, a slit coating method, a capillary coating method, a spray coating method, a nozzle spray coating method, or the like can be used.

As the printing method, various printing methods such as a gravure coating printing method, a screen printing method, a flexographic printing method, an offset printing method, a reverse printing method, and an inkjet printing method can be used.

< electrolyte >

The electrolyte is filled between the first electrode and the second electrode.

As the electrolyte, for example, inorganic ion salts such as alkali metal salts, alkaline earth metal salts and the like, 4-valent ammonium salts, acids, alkali supporting salts can be used. Specific examples thereof include LiClO₄，LiBF₄，LiAsF₆，LiPF₆，LiCF₃SO₃，LiCF₃COO，KCl，NaClO₃，NaCl，NaBF₄，NaSCN，KBF₄，Mg(ClO₄)₂，Mg(BF₄)₂And the like.

As a material of the electrolyte, an ionic liquid may also be used. Among them, organic ionic liquids are more suitable because they have a molecular structure showing a liquid state in a wide range of temperature fields including room temperature.

Examples of the cationic component in the molecular structure include imidazole derivatives such as N, N-dimethylimidazolium salt, N-methylethylimidazolium salt, and N, N-methylpropylimidazolium salt; pyridine derivatives such as N, N-dimethylpyridine salts and N, N-methylpropylpyridine salts; aliphatic 4-valent ammonium such as trimethylpropylammonium salt, trimethylhexylammonium salt and triethylhexylammonium salt. As the anionic component in the molecular structure, a fluorine-containing compound is preferably used in view of stability in air, and examples thereof include BF₄ ^－，CF₃SO₃ ^－，PF₄ ^－，(CF₃SO₂)₂N^－And the like.

As the electrolyte material, an ionic liquid in which the above-described cationic component and the above-described anionic component are arbitrarily combined is preferably used.

The ionic liquid may be directly dissolved in any one of the photopolymerizable monomer, oligomer, and liquid crystal material. When the solubility is poor, the solution may be dissolved in a small amount of a solvent and mixed with any one of the photopolymerizable monomer, oligomer, and liquid crystal material.

Examples of the solvent include propylene carbonate, acetonitrile, γ -butyrolactone, ethylene carbonate, cyclosulfane, dioxolane, tetrahydrofuran, 2-methyltetrahydrofuran, dimethyl sulfoxide, 1, 2-dimethoxyethane, 1, 2-ethoxymethoxyethane, polyethylene glycol, alcohols, and a mixed solvent thereof.

The electrolyte is not limited to a low viscosity liquid, and may be in various forms such as a gel form, a polymer crosslinked form, and a liquid crystal dispersed form. When the electrolyte is in a gel or solid state, advantages such as improvement in element strength and improvement in reliability can be obtained.

As the solidification method, a method of holding an electrolyte and a solvent in a polymer resin is preferable. High ionic conductivity and solid strength can thereby be obtained.

Further, as the polymer resin, a resin which can be hardened by light is preferable. This is because the device can be manufactured at a low temperature in a short time as compared with a method of forming a thin film by thermal polymerization or evaporation of a solvent.

The average thickness of the electrolyte layer composed of the electrolyte is not particularly limited and may be appropriately selected according to the purpose, and is preferably 100nm to 10 μm.

< counter electrode layer >

The counter electrode layer has an opposite chemical reaction with the electrochromic display layer to obtain a charge balance, and inhibits the first electrode or the second electrode from being corroded or deteriorated due to the irreversible redox reaction. The electrochromic display layer herein means a "layer containing an oxidative color-developing electrochromic display compound" (first layer). The reverse reaction also includes a function as a capacitor in addition to the redox reaction on the electrode layer.

The material of the counter electrode layer is not particularly limited as long as it functions to prevent corrosion of the first electrode and the second electrode due to irreversible redox reaction, and may be appropriately selected according to the purpose. Examples thereof include antimony tin oxide, nickel oxide, titanium oxide, zinc oxide, tin oxide, and a conductive or semiconductive metal oxide containing a plurality of these oxides.

When importance is attached to prevention of deterioration, the counter electrode layer may be formed of a porous film to such an extent that electrolyte injection is not hindered. For example, when conductive or semiconductive metal oxide fine particles such as antimony tin oxide, nickel oxide, titanium oxide, zinc oxide, and tin oxide are fixed to the second electrode with a binder such as acrylic, alkyd, isocyanate, urethane, epoxy, or phenol, a porous film that satisfies the functions of a permeable electrolyte and a deterioration prevention layer can be obtained.

As a material constituting the conductive or semiconductive nanostructure, a metal oxide is preferable from the viewpoint 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 oxide, ferrite, hafnium oxide, tungsten oxide, iron oxide, copper oxide, nickel oxide, cobalt oxide, barium oxide, strontium oxide, vanadium oxide, aluminosilicate, calcium phosphate, and the like. These metal oxides may be used alone or in combination of two or more.

< other Components >

The other member is not particularly limited and may be appropriately selected according to the purpose, and examples thereof include a support, an insulating porous layer, and a protective layer.

A support

As the support, any known organic material or inorganic material can be used as long as it is a transparent material capable of supporting each layer.

Examples thereof include glass substrates such as alkali-free glass, borosilicate glass, float glass, and soda-lime glass. Further, resin substrates such as polycarbonate resin, acrylic resin, polyethylene, polyvinyl chloride, polyester, epoxy resin, melamine resin, phenol resin, polyurethane resin, and polyimide resin may be used. In addition, a transparent insulating layer, a UV-blocking layer, an antireflection layer, or the like may be coated on the surface of the support in order to improve the water vapor barrier property, the gas barrier property, the ultraviolet resistance, and the visibility.

The shape of the support is not particularly limited, and may be rectangular or circular.

The support may be a laminate of a plurality of materials, and for example, if the electrochromic display dimming element is sandwiched between two glass substrates, the water vapor barrier property and the gas barrier property can be improved.

Insulating porous layer-

The insulating porous layer has a function of isolating so that the first electrode and the second electrode are electrically insulated while retaining the electrolyte.

The material of the insulating porous layer is not particularly limited as long as it is porous, and organic materials, inorganic materials, and composites thereof having high insulating properties and durability and excellent film forming properties are preferably used.

Examples of the method for forming the insulating porous layer include a sintering method (in which fine polymer particles, fine inorganic particles, a binder or the like are added and locally melted to utilize pores formed between the particles), an extraction method (in which a structural layer is formed using an organic or inorganic substance soluble in a solvent, a binder insoluble in a solvent, or the like, and then the organic or inorganic substance is dissolved in the solvent to obtain pores), a foaming method in which the structural layer is foamed, a phase inversion method in which a mixture of the fine polymer substances is phase-separated by operating a good solvent and a poor solvent, and a radiation irradiation method in which various types of radiation are irradiated to form pores.

Protective layer-

The protective layer functions to protect the element from external stress or a cleaning agent, prevent leakage of an electrolyte, stabilize the operation of the electrochromic display element, and prevent entry of unnecessary substances such as moisture, oxygen, and the like in the atmosphere.

As the material of the protective layer, ultraviolet-curable or thermosetting resins can be used, and specific examples thereof include acrylic resins, urethane resins, and epoxy resins.

The thickness of the protective layer is not particularly limited and may be suitably selected according to the purpose, and is preferably 1 to 200 μm.

Here, an example of the structure of the electrochromic display element of the present invention is shown in fig. 1.

The electrochromic display element of fig. 1 comprises a support (1), a first electrode (2), a second electrode (3) disposed opposite to the first electrode with a gap therebetween, and an electrolyte (5) between the electrodes.

The surface of the first electrode (2) is provided with a layer (4) containing the oxidative color-developing electrochromic display compound according to the present invention. The specific compound (6) according to the present invention is present in a state of being attached to or adsorbed on the counter electrode layer (7). The layer (4) develops color on the surface of the first electrode by an oxidation reaction and is decolored by a reverse reaction (reduction reaction).

Application-

The electrochromic display element of the present invention can stably operate, and is particularly excellent in transparency and light resistance. Therefore, the present invention can be applied to large display panels such as electrochromic displays and stock price display panels, light control elements such as antiglare glasses and light control glasses, low voltage driving elements such as touch panel type key switches, optical memories, electronic paper, electronic photo albums, and the like.

[ examples ] A method for producing a compound

The present invention will be described in more detail below by way of examples and comparative examples, but the present invention is not limited to these examples. In the examples, "parts" are "parts by mass".

Example 1

Formation of an electrochromic display layer onto the first electrode

In order to form an electrochromic display layer on the first electrode, an oxidative color-developing electrochromic display composition was prepared in the following compounding ratio.

[ compounding ratio ]

An oxidative color-developing triarylamine compound represented by the following chemical formula (A): 50 portions of

Chemical formula (A)

IRGACURE184 (manufactured by BASF JAPAN corporation): 5 portions of

PEG400DA having 2-functional acrylate (manufactured by Nippon chemical Co., Ltd.): 50 portions of

Methyl ethyl ketone: 900 portions

The obtained oxidative color-developing electrochromic composition was applied to an ITO glass substrate (40 mm. times.40 mm, thickness 0.7mm, ITO film thickness: about 100nm) as a first electrode by spin coating. The obtained coating film was subjected to UV irradiation with a UV irradiation apparatus (SPOT CURE, manufactured by Usio electric Motor Co.) at 10m W for 60 seconds and to annealing treatment at 60 ℃ for 10 minutes to form a crosslinked electrochromic display layer having an average thickness of 0.4. mu.m.

Formation of a counter electrode layer on the second electrode

A Titanium oxide nanoparticle dispersion (trade name: SP210, manufactured by Showa Titanium corporation, average particle diameter: about 20nm) was applied by spin coating to an ITO glass substrate (40 mm. times.40 mm, thickness: 0.7mm, ITO film thickness: about 100nm) as a second electrode, and annealing treatment was performed at 120 ℃ for 15 minutes as a deterioration prevention layer to form a Titanium oxide particle film having a thickness of 1.0. mu.m.

Next, a composition of 5 parts of a compound represented by the following chemical formula (B) and 95 parts of methanol was prepared, and the composition was applied to a titanium oxide particle film by a spin coating method to form a counter electrode layer.

Chemical formula (B)

Modulation of the electrolyte

An electrolyte solution was prepared in the following proportions.

IRGACURE184 (manufactured by BASF JAPAN corporation): 5 portions of

PEG400DA (manufactured by japan chemicals): 100 portions of

50 parts of 1-ethyl-3-methylimidazolium tetracyanoborate (Merck)

Production of electrochromic display elements

30mg of the electrolyte solution was measured by a micropipette and dropped onto the counter electrode layer of the ITO glass substrate having the counter electrode layer. On the top surface of the substrate, an ITO glass substrate having a crosslinked electrochromic display layer was bonded so that the electrode lead-out portion was present, and the electrochromic display layer was opposed to the counter electrode layer, thereby producing a bonded element.

This pasted element was irradiated with UV (wavelength 250nm) radiation (SPOT CURE, manufactured by Usio electric Co., Ltd.) for 60 seconds at 10mW to fabricate an electrochromic display element.

< evaluation of Driving Voltage based on transmittance Change and CV characteristic >

The color development/color loss of the produced electrochromic display element was confirmed. Specifically, CV measurement was performed by connecting measurement terminals to the lead-out portion of the first electrode layer and the lead-out portion of the second electrode layer.

The electrical characteristics were measured at an insertion speed of-50 mV/sec. The average transmittance at this time was monitored at 380 to 780nm using USB4000 (manufactured by Ocean Optics), and the coloring voltage until the average transmittance reached about 30% and the decoloring voltage until the image was returned to the decoloring state were measured. As a result, coloring voltage: -2.4V, erasing voltage: + 0.3V.

Fig. 2 and 3 show the results of the current change (IV characteristic) with respect to the voltage and the transmittance change (TV characteristic) with respect to the voltage at this time.

Comparative example 1

An element was produced in the same manner as in example 1 except that the titanium oxide particle film was used as it is without spin coating the compound represented by the chemical formula (B) in "formation of the counter electrode layer on the second electrode" in example 1, and the coloring voltage and the decoloring voltage were determined in the same manner as in example 1. As a result, coloring voltage: -2.4V, erasing voltage: + 2.0V.

Fig. 4 and 5 show the results of the current change (IV characteristic) with respect to the voltage and the transmittance change (TV characteristic) with respect to the voltage at this time, respectively.

Comparative example 2

An electrochromic display element was produced in the same manner as in example 1, except that a composition of 5 parts of decylphosphonic acid (manufactured by tokyo chemical corporation) and 95 parts of methanol, which is represented by the following chemical formula (C), was prepared instead of the composition of the compound represented by the chemical formula (B) in "formation of the counter electrode layer on the second electrode" in example 1, and the counter electrode layer was formed by applying the composition onto the titanium oxide particle film by a spin coating method. In this element, CV characteristics were measured in the same manner as in example 1, and a coloring voltage and a decoloring voltage were obtained, and no coloring was observed even when applied at-5V. For reference, the current change (IV characteristic) with respect to voltage is shown in fig. 6.

Chemical formula (C)

Example 2

An electrochromic display element was produced in the same manner as in example 1, except that the compound represented by the chemical formula (a) in "formation of an electrochromic display layer on a first electrode" in example 1 was changed to an oxidative color-developing electrochromic display compound represented by the following chemical formula (D). In this cell, the coloring voltage and the decoloring voltage were determined in the same manner as in example 1. The results are shown in Table 1.

Chemical formula (D)

Comparative example 3

An electrochromic display element was produced in the same manner as in example 2, except that the titanium oxide particle film was used as it is without spin coating the compound represented by the chemical formula (B) in "formation of the counter electrode layer on the second electrode" in example 2. In this cell, the coloring voltage and the decoloring voltage were determined in the same manner as in example 1. The results are shown in Table 1.

Example 3

The operation of "formation of an electrochromic display layer on a first electrode" in example 1 was changed as follows to form an electrochromic display layer having an oxidative color-developing triarylamine compound.

A Titanium oxide nanoparticle dispersion (trade name: SP210, manufactured by Showa Titanium corporation, average particle diameter: about 20nm) was applied to an ITO glass substrate (40 mm. times.40 mm, average thickness: 0.7mm, ITO film thickness: about 100nm) as a first electrode layer by spin coating, and annealing was carried out at 120 ℃ for 15 minutes to form a Titanium oxide particle film having a thickness of about 1.0. mu.m.

Next, an oxidative color-developing electrochromic display composition having the following composition was prepared, which was placed on the titanium oxide particle film.

[ compounding ratio ]

An oxidative color-developing triarylamine compound represented by the following chemical formula (E): 50 portions of

Chemical formula (E)

Methanol: 950 portions of

The obtained oxidation color-developing electrochromic display composition was applied to the titanium oxide particle film by a spin coating method, and annealed at 120 ℃ for 10 minutes to form an electrochromic display layer on the titanium oxide particle film.

Next, an electrochromic display element was produced in the same manner as in example 1, except that the first electrode layer formed by the electrochromic display layer was used, and the coloring voltage and the decoloring voltage were determined in the same manner as in example 1. The results are shown in Table 1.

Comparative example 4

An electrochromic display element was produced in the same manner as in example 3, except that the titanium oxide particle film was used as it is without spin coating the compound represented by the chemical formula (B) in "formation of the counter electrode layer on the second electrode" in example 3. In this cell, the coloring voltage and the decoloring voltage were determined in the same manner as in example 1. The results are shown in Table 1.

Example 4

The operation of "formation of an electrochromic display layer on a first electrode" in example 1 was changed as follows to form an electrochromic display layer having an oxidative color-developing triarylamine polymer.

That is, first, an oxidative color-developing electrochromic display composition having the following composition was prepared.

[ compounding ratio ]

An oxidative color-developing triarylamine polymer 103 represented by the following chemical formula (F): 50 portions of

Chemical formula (F)

(in the formula, n represents an integer of 180 to 150 (estimated from polystyrene conversion))

Toluene: 950 portions of

Next, the obtained oxidation color-developing electrochromic display composition was applied to an ITO glass substrate (40 mm. times.40 mm, thickness: 0.7mm, ITO film thickness: about 100nm) by a spin coating method, and dried at 120 ℃ for 10 minutes to form an electrochromic display layer.

An electrochromic display element was produced in the same manner as in example 1, except that this electrochromic display layer was used. In this cell, the coloring voltage and the decoloring voltage were determined in the same manner as in example 1. The results are shown in Table 1.

Comparative example 5

An electrochromic display element was produced in the same manner as in example 4, except that the titanium oxide particle film was used as it is without spin coating the compound represented by the chemical formula (B) in "formation of the counter electrode layer on the second electrode" in example 4. In this cell, the coloring voltage and the decoloring voltage were determined in the same manner as in example 1. The results are shown in Table 1.

TABLE 1

	Colour development voltage	Achromatic voltage		Colour development voltage	Achromatic voltage
						Example 1	-2.4	+0.3	Comparative example 1	-2.4	+2.0
Example 2	-2.4	+0.3	Comparative example 3	-2.4	+2.0
						Example 3	-2.4	+0.8	Comparative example 4	-2.4	+2.2
Example 4	-2.3	+1.0	Comparative example 5	-2.3	+2.0

As is clear from example 1 and comparative example 1, when the specific compound according to the present invention is added to the second electrode, the decoloring voltage is lowered and the driving is possible at a lower voltage than when the specific compound is not added. Further, in comparative example 2 using an alkylphosphonic acid, since an electrochromic display operation cannot be obtained, it can be said that the effect is obtained by the compound having a specific structure according to the present invention.

As is clear from table 1, the addition of the specific compound of the present invention to the second electrode can provide an effect on a low voltage even in an electrochromic display element having different forms of oxidation color development.

The embodiments of the present invention have been described above with reference to the drawings, but the present invention is not limited to the above embodiments. Various modifications may be made within the scope of the technical idea of the present invention, and they are within the scope of the present invention.

Claims

1. An electrochromic display element having a first electrode, a second electrode, and an electrolyte between the first electrode and the second electrode, characterized in that:

chemical formula (1)

In the above formula, R₁～R₅Each independently represents a hydrogen atom, a halogen atom, a monovalent organic group, R₁～R₅Wherein the monovalent organic group in the above specific compound is an organic group selected from alkyl, alkenyl, alkynyl, aryl, heteroaryl, alkoxy, aryloxy, and heteroaryloxy.

2. The electrochromic display element according to claim 1 wherein R in said specific compound is₃Containing a functional group capable of bonding directly or indirectly to a hydroxyl group.

3. The electrochromic display element according to claim 1 or 2, wherein said functional group capable of bonding directly or indirectly to a hydroxyl group is a functional group selected from a phosphonic acid group, a phosphoric acid group, a carboxylic acid group, a sulfonyl group, a silyl group, and a silanol group.

4. The electrochromic display element according to claim 1 or 2, wherein the functional group capable of bonding directly or indirectly to a hydroxyl group contains an alkyl group, or an aryl group substituted with an alkyl group.

5. The electrochromic display element according to claim 1 or 2, wherein the specific compound is bonded to or adsorbed on a conductive or semiconductive nanostructure provided on the second electrode.

6. The electrochromic display element according to claim 1 or 2, wherein the layer containing the specific compound represented by the above chemical formula (1) is a counter electrode layer provided on the second electrode.