JPH07207260A - Material for electrochromic element and electrochloromic element made thereof - Google Patents

Abstract

PURPOSE:To produce a material for an electrochromic element which has a high coloration efficiency, can easily form a thin film of a large area and can give a long-life electrochromic element by making it of fine particles formed by the vaproization-in-gas method. CONSTITUTION:By the vaporization-in-gas method comprising setting a material (e.g. phthalocyanine) for an electrochromic element on a coil or boat heating element for direct or indirect heating, and energizing the heating element in a vessel containing a low-pressure gas of Ar, He or the like to sublime and evaporate the material, fine particles of the material are produced. These partciles are dispersed in a solution containing a resin (e.g. polyvinyl butyral) and the obtained solution is applied to a transparent electrode base plate by, for example, a coating method to form an elecrochromic layer. Thus, an electrochromic element can be produced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrochromic device having a high coloring efficiency, a large area, and a long life.

[0002]

2. Description of the Related Art An electrochromic device that applies electrochromism in which a color is reversibly changed by applying a current has a memory property for display, consumes less power, has no viewing angle dependency, and is suitable for large-area display. Due to the advantages such as being provided, researches on dimming elements, display elements and the like have been conducted. An electrochromic device generally has a laminated structure in which a transparent electrode, an electrolyte and an electrochromic layer are combined. The thin film used as the electrochromic layer is
A metal compound such as tungsten oxide, an inorganic or organic material such as a metal complex and an organic dye can be used. These thin film layers are formed by vacuum vapor deposition, sputtering, electric field film formation, chemical film formation, or the like.

Film formation by vacuum vapor deposition or sputtering requires an expensive apparatus, and it is necessary to maintain a high vacuum inside the apparatus. Further, in order to obtain an electrochromic device with high coloring efficiency, it is necessary to increase the film thickness of the electrochromic layer to promote the movement of ions, the vapor deposition time becomes long, and the film formation conditions are strictly controlled. There is a need. These problems make it difficult to save energy and increase the area of the device. In order to form a thin film by the electric field film formation or the chemical film formation method, it is necessary to strictly control the film formation conditions, and there is a problem that raw materials and devices used are limited. Further, when a display pattern is required, etching,
Special processing such as masking is required.

As a chemical film forming method, for example, a method in which a tungsten oxide prepared by applying a solution of an organic tungsten compound dissolved in an organic solvent on a transparent electrode substrate and then heating it is used as an electrochromic layer ( JP-A-56-38379), a method of forming an electrochromic layer by coating and drying a transition metal compound solution such as an alcohol solution of tungsten chloride on an electrode substrate (JP-A-55-11207), a chlorine-based tungsten system. After reacting the compound with an organic acid, it is reacted with an organic solvent having a hydroxy group to synthesize an organic compound of tungsten, and the organic compound of the tungsten compound is supplied onto a transparent electrode substrate and then heated to form an electrochromic layer. Forming method (JP-A-62-112132, JP-A-63-15)
No. 228, JP-A-63-15229), but in these methods, a solution of an organometallic compound in an organic solvent is applied on a substrate and then heated.
It is difficult to obtain a stable electrochromic device because the heating temperature is difficult to control and the organic metal compound is oxidized, and the thermal expansion coefficient and thermal stability of the substrate and coating are different. It was

Further, since ordinary organic compounds contain impurities such as unreacted products, intermediate products, and inorganic salts, when used in electrochromic devices, ionic conduction is hindered and good results are obtained. It was difficult to obtain electrochromic properties. In the conventional sublimation purification method under high vacuum, the refined fine powder is scattered during the purification to lower the recovery yield, and the impurities cannot be sufficiently removed to improve the purity. Further, in the sublimation purification method, the particle size increases after purification, which makes it difficult to carry out the dispersion step for preparing a coating solution during chemical film formation. Large particles are dry- or wet-milled into fine particles. I need to add more steps,
It was difficult to set those optimization conditions.

[0006]

DISCLOSURE OF THE INVENTION The present invention has the drawbacks of the conventional electrochromic device, such as low coloring efficiency, energy saving when forming the electrochromic layer, difficulty in increasing the area, and short life. It was made to overcome the shortcomings.

[0007]

That is, the present invention relates to an electrochromic device material comprising fine particles produced by an in-gas evaporation method. Further, the present invention relates to an electrochromic element forming material obtained by dispersing the above electrochromic element material in a solution containing a solvent or a resin. Furthermore, the present invention relates to an electrochromic device comprising an electrochromic layer containing the above electrochromic device material formed on a transparent electrode substrate.

The electrochromic device material of the present invention is refined by a gas evaporation method and made into fine particles. In the gas evaporation method, the electrochromic element material is set in a coil-shaped or boat-shaped heating element capable of direct or indirect heating, and low-pressure Ar,
In this method, a heating element is heated in a container into which a gas such as He, nitrogen, oxygen, or ammonia is introduced to sublimate or evaporate the material. An inert gas such as Ar or He can be used to obtain the metal fine particles, an oxygen gas can be used to obtain the metal oxide fine particles, and a nitrogen gas or an ammonia gas can be used to obtain the metal nitride fine particles. . Further, high purity organic compound fine particles can be obtained by using a gas such as Ar, He and nitrogen, and oxygen doping can also be performed by using an oxygen gas. Evaporation is ^10-5
It is carried out under a pressure of 10 Toor. The evaporate collides with gas molecules in the container and is made into fine particles, and the size of the fine particles can be controlled by the sublimation temperature, the type of gas, the flow rate of gas, the pressure, and the like. The particle size of the fine particles can be controlled within the range of 5 nm to 10 μm, and preferably within the range of 10 nm to 100 nm. A method for producing fine particles by the gas evaporation method is described in, for example, JP-A-1-162705,
JP-A-2-97501, JP-A-2-131134,
JP-A-2-153008, JP-A-2-153807
No. 3,70,738, Japanese Patent Publication No. 3-52401, and the like.

In the in-gas evaporation method, evaporated molecules are aggregated or united in an inert gas to form fine particles, so that fine particles with few defects and contamination can be obtained. Further, the method of producing fine particles by the in-gas evaporation method has the advantages that purification and control of the particle size of the produced particles are easy, the particle size distribution of the particle size is sharp, the yield is high, and the purity of the fine particles is high. for that reason,
The electrochromic device using the electrochromic device material of the present invention has high electrochromic properties such as high coloring efficiency, good memory properties, high contrast ratio, fast response speed, and high purity even on a large-area electrode. It is possible to obtain a smooth electrochromic thin film.

The electrochromic device material used in the electrochromic layer of the present invention may be any known substance exhibiting electrochromism. Examples of the inorganic substance include Ti, V, Cr, Mn, Fe, and C.
o, Ni, Cu, Zr, Nb, Mo, Tc, Ru, R
h, In, Sn, W, Re, Os, Ir, Pr, Sm,
Metals such as Dy, Ho, Er and Lu, or metal compounds such as oxides, nitrides and hydroxides thereof, such as W
O ₃ , MoO ₃ , IrO _x , NiO _x , CoO _x , TiO ₂ ,
Cr ₂ O ₃ , V ₂ O ₅ , Ta ₂ O ₅ , Nb ₂ O ₅ , InN, Sn
N _x , ZrNCl, Ir (OH) ₂ , Ni (OH) ₂ , C
Examples thereof include inorganic substances such as o (OH) ₂ and solid solutions thereof, but are not limited thereto. Here, X does not represent a constant numerical value and is not necessarily an integer. Organic substances include Prussian blue, bathophenatroline, bipyridine, phthalocyanine, diphthalocyanine,
Metal complex substances such as porphyrin, phenanthroline, pyridinoporphyrazine, viologen, 2, 4, 5, 7
-Tetranitro-9-fluorenone, 2,4,7-trinitrofluorenylidene malononitrile, tetracyanoquinodimethane, tetrathiofulvalene, o-aminophenol, o-phenylenediamine, styryl derivative, hydrazone derivative, thiophene derivative , A pyrrole derivative,
Aniline derivative, or polypyrrole, poly (3-methylthiophene), poly (N-vinylcarbazole),
Poly-ruthenium (4-methyl-4'-vinyl-2,
There are organic polymer substances such as 2′-bipyridine) ₃ .

The oxidative coloring type electrochromic layer of the electrochromic device is a film in which a substance exhibiting electrochromism is oxidized to develop a color, and the reduction coloring type electrochromic layer is a film in which a substance exhibiting electrochromism is reduced to develop a color. Is.

The electrochromic layer of the present invention is applied by a physical method such as vacuum deposition or sputtering of metal, metal compound or organic fine particles, and a coating liquid in which the metal, metal compound or organic fine particles are dispersed together with a resin if necessary. It is formed by a chemical method such as a coating method, an LB film method, and a plasma polymerization method. The electrochromic layer produced by vacuum deposition or sputtering is usually 1T
The metal compound is heated in a low vacuum container at or below to form a thin film on the transparent electrode substrate. The atmosphere may be vacuum, nitrogen, chlorine, hydrogen, ammonia, argon, helium, or the like. Resins used in chemical methods are known, and polyvinyl butyral, polyacrylate, polycarbonate, polyester, phenoxy, acrylic, acrylic polyol, polyamide, urethane, epoxy, silicone, polystyrene, cellulose, polyvinyl chloride, vinyl chloride It may be a polymer, a phenol, a melamine resin or the like, or a mixture of these resins. Isocyanate, melamine, or the like may be added to these resins or the prepared coating liquid to form an electrochromic layer by thermosetting, UV light or electron beam curing. The thickness of the electrochromic layer is preferably 0.01 to 10 μm.

A known solvent or a mixture thereof can be used as the dispersion solvent used in the preparation of the electrochromic layer by a chemical method, and any of an organic solvent, an inorganic solvent, water and the like may be used. The organic solvent is alcoholic,
Any of ketone type, ether type, ester type, hydrocarbon type and halogen type may be used. As a specific example, methanol,
Examples thereof include ethanol, isopropyl alcohol, acetone, methyl ethyl ketone, diethyl ether, dipropyl ether, tetrahydrofuran, 1,4-dioxane, toluene, xylene, carbon tetrachloride, chloroform and the like. As the inorganic solvent, liquid ammonia, silicone oil, acid or alkaline aqueous solution is suitable. Also,
Inorganic or organic antioxidants, ultraviolet absorbers and the like may be added to the electrochromic layer to prevent the layer from deteriorating.

The electrochromic device of the present invention includes a transparent electrode, an electrolyte, an electrochromic layer, an electrochromic device having a laminated structure of a transparent electrode, or a transparent electrode, a first electrochromic layer, an electrolyte and a second electrochromic layer. , An electrochromic device including a transparent electrode is preferable, but the device structure is not limited to these. The oxidative coloring type electrochromic layer of the electrochromic element is a film in which a substance exhibiting electrochromism is oxidized to develop a color, and the reduction coloring type electrochromic layer is a film in which a substance exhibiting electrochromism is reduced to develop a color.

The electrode of the electrochromic device of the present invention is preferably a transparent electrode having a high electric conductivity such as tin oxide, indium oxide or ITO, and the substrate is a solid such as glass or resin and has a high light transmittance. Any material may be used. A known electrolyte can be used as the electrolyte, and either an inorganic or organic electrolyte may be used, but a resin or a dielectric containing a solvent or a cation having a high ionic conductivity such as H, Li, K, Na, or Mg is preferable. The electrolyte may be liquid, solid solution, or solid. Thickness of electrolyte is 1m
m-0.01 micrometer is preferable.

[0016]

EXAMPLES The present invention will be specifically described below with reference to examples. However, the present invention is not limited to the following examples. (Particle Preparation Method 1) 20 g of nickel was placed in the sublimation boat (10) in the particle evaporation chamber (1) shown in FIG. 1, the vapor deposition chamber was evacuated to 10 ⁻⁴ Torr, and then He gas was introduced. The sublimation boat is heated to melt the nickel in the sublimation boat at 1800 ° C. Gas inlet at the bottom of the evaporation chamber (9)
To supply He gas at a flow rate of 10 liters / minute to evaporate the fine particles by setting the degree of vacuum in the evaporation chamber to 2 Torr.
The particulate collection chamber (13) was set to 10 ^-3 Too by a vacuum pump
After setting to r, oxygen gas is injected from the upper gas inlet (15) to keep the fine particle recovery chamber at 2 × 10 ^-2 Toor. At that time, by making a pressure difference between the fine particle evaporation chamber and the fine particle rising chamber, the fine particles rising from below were conveyed to the fine particle collecting chamber and collected by the cooling mesh plate (14). From the powder X-ray diffraction pattern and infrared absorption spectrum of the recovered fine particles, it was confirmed that they were nickel oxide fine particles. 11.3g
The obtained nickel fine particles were and the average particle size measured from the electron micrograph was 20 nm.

(Particle preparation method 2) 20 g of dysprosium diphthalocyanine was placed in the sublimation boat (10) in the particle evaporation chamber (1) shown in FIG. 2 and the evaporation chamber was set to 10 ^-5 To.
After exhausting to rr, He gas is introduced so that the degree of vacuum is 0.1 Toor. Dysprosium diphthalocyanine in the sublimation boat was heated at 350 ° C. for 30 minutes, and fine particles were deposited on the recovered film (4) cooled by the cooling plate (3). From the powder X-ray diffraction pattern and infrared absorption spectrum of the recovered fine particles, it was confirmed that they were dysprosium diphthalocyanine fine particles. 15.2 g of dysprosium diphthalocyanine fine particles were obtained, and the average particle size was 15 nm.

Example 1 Nickel oxide fine particles 2.0 obtained by the fine particle preparation method 1
g, 10 ml of methyl ethyl ketone, and 0.6 g of a dispersion medium composed of xylene: butyl acetate: acrylic polyol = 1: 1: 1 (weight ratio) were put in a ball mill and dispersed for 24 hours to prepare a dispersion liquid. Next, IT of 10Ω / cm ²
The above dispersion was applied onto an O glass transparent electrode by a spin coater at 2000 rpm to obtain a thin film of 0.2 μm. This coating film was dried at 50 ° C. for 6 hours to obtain an electrochromic layer. The haze ratio of this layer is 1.5%,
It turned out to be highly transparent. Furthermore, 1 standard KOH
The electrochromic film to which +1 V was applied for 30 seconds as an electrolyte showed an extremely dark brown color, and the transmittance at 600 nm was 12%. The electrochromic layer applied with -1 V for 1 minute has an extremely high transmittance,
The transmittance in nm was 90%.

The electrochromic layer thus obtained was used as a first electrochromic layer, and an ITO electrode of 10 Ω / cm ² was used as a second electrochromic layer. After sandwiching the two electrochromic layers with a spacer and adhering them with an epoxy resin, a 0.1 N KOH aqueous solution was injected between the electrochromic layer and the counter electrode to prepare an electrochromic element as an electrolyte. As a result of examining the coloring and decoloring response of the obtained electrochromic device, it is found that the transmittance changes from 15% to 70% in 10 seconds, and the responsiveness is good. In addition, from the measurement result of the cyclic voltammogram, the injected charge amount of this electrochromic device is 10 mC / cm.
² was a good coloring efficiency.

Example 2 The first electrochromic layer was formed by vacuum evaporation method 1
Except for forming by vacuum of 0 ^{over 5} Toor was prepared an electrochromic device in the same manner as in Example 1. In this electrochromic device, the transmittance changed from 15% to 70% for 13 seconds, and from the measurement result of the cyclic voltammogram, the injected charge amount was 8 mC / cm ² , showing a good coloring efficiency.

Example 3 Example 1 was repeated except that the tungsten trioxide fine particles prepared by the same method as the fine particle preparation method 1 as the second electrochromic layer were propylene carbonate containing 1M lithium perchlorate as the electrolyte. An electrochromic device was produced in the same manner as in. In this electrochromic device, the transmittance changed from 15% to 70% for 9 seconds, and from the measurement result of the cyclic voltammogram, the injected charge amount was 12 mC / cm ² , showing a good coloring efficiency.

Example 4 2.0 g of dysprosium diphthalocyanine fine particles obtained by the method 2 for producing fine particles, 10 ml of 1,4-dioxane, xylene: butyl acetate: acrylic polyol = 1: 1: 1
A dispersion medium (0.6 g) (weight ratio) was placed in a ball mill and dispersed for 24 hours to prepare a dispersion liquid. Then 10
The above dispersion liquid was applied at 2000 rpm by a spin coater onto an ITO glass transparent electrode of Ω / cm ² to form 0.3.
A thin film of μm was obtained. This coating film was dried at 50 ° C. for 6 hours to obtain an electrochromic layer. The haze ratio of this layer is 1
%, And it was found that the transparency was high. Further, a cyclic voltammogram was measured using 1N H ₂ SO ₄ as an electrolyte. The initial film is green with absorption peaks at 460nm and 670nm, but when + 0.7V is applied to oxidize the film, it becomes red with absorption peaks at 500nm and 700nm, and -0.6V is applied to the film. Was reduced to a red color with absorption peaks at 630 nm and 700 nm. From the measurement results of cyclic voltammogram,
The amount of injected charges was 8 mC / cm ² , showing good coloring efficiency.

[0023]

EFFECT OF THE INVENTION The electrochromic layer formed from the fine particles formed by the gas evaporation method has high coloring efficiency, and an electrochromic device in which a large-area thin film can be easily formed can be manufactured. Further, the fine particles of the present invention can remove as much as possible raw materials present in particles having a large particle size and impurities mixed in during synthesis or purification, and can be used for physical or chemical thin film formation such as vacuum deposition or sputtering. Also, a uniform thin film with high purity can be obtained. The electrochromic device manufactured using the material of the present invention is used for panel displays, signboards, light control glass, antiglare mirrors, etc., and its industrial significance is great.

[Brief description of drawings]

FIG. 1 is a schematic view of an in-gas evaporation method apparatus used in Examples.

FIG. 2 is a schematic view of a gas evaporation method apparatus used in Examples.

[Explanation of symbols]

 1. Fine particle evaporation chamber 2. Recovery roll 3. Cooling plate 4. Film 5. Exhaust port 6. Vacuum gauge 7. Vacuum valve 8. Vacuum pump 9. Lower gas inlet 10. Sublimation boat 11. Sample 12. Evaporative heating power supply 13. Fine particle collection chamber 14. Cooling mesh plate 15. Upper gas inlet

Claims (3)

[Claims] 1. An electrochromic device material comprising fine particles produced by an in-gas evaporation method. 2. An electrochromic element forming material obtained by dispersing the electrochromic element material according to claim 1 in a solution containing a solvent or a resin. 3. An electrochromic device comprising an electrochromic layer containing the electrochromic device material according to claim 1 formed on a transparent electrode substrate.