JP2971482B2 - Electrochromic device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an element (electrochromic (EC) element) that changes color when a voltage is applied, and particularly to an all-solid-state EC element.

(Background technology)

EC materials exhibit their function by changing the absorption spectrum of light due to the oxidation-reduction reaction. It is used for memory sensors and the like that utilize the characteristics.

For all-solid-state EC materials, solid electrolytes have been studied as ion supply materials. However, the conventional EC material using the solid electrolyte has a low response speed and a large deterioration. Recently, improvements in solid electrolytes have been made, but satisfactory performance has not yet been obtained.

The inventors of the present invention have studied the properties of the extended conjugated quinone-based compound, and have found that this compound reversibly assumes an oxidized state and a reduced state. Furthermore, the oxidation of these
Since the reduced state exists stably and the light absorption spectrum changes drastically, it was examined as a new EC material.

(Basic idea of the invention)

In the extended conjugated quinone-based compound, the oxidation-reduction state proceeds reversibly, the oxidation-reduction state is stable, and the light absorption spectrum changes significantly. By sandwiching this between electrodes, the EC operation was confirmed without using a solid electrolyte, and the present invention was completed.

[Disclosure of the Invention]

That is, the present invention provides an extended conjugated quinone-based compound between at least one of two electrode layers in which one electrode is light-transmitting, and is present between the charge injection layer or the charge injection layer. An electrochromic device having a color tone changing layer that is laminated on the device.

 Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 shows one embodiment of the device of the present invention. That is, at least one is provided with two electrode layers 2 and 4 that are light-transmitting, and between these two electrodes 2 and 4 is a color change layer (hereinafter abbreviated as EC layer) made of an extended conjugated quinone compound. 3) An EC element provided with 3. FIG. 2 is an example of another embodiment of the present invention.
An EC layer 13 and a charge injection layer 15 are stacked between 2 and 14. In FIG. 2, the electrode in contact with the substrate is called a first electrode, and the electrode on the opposite side is called a second electrode. FIG. 3 shows still another embodiment, in which the EC layer 13 has the charge injection layers 15 and 1.
It exists between 5 '.

The EC layer in the present invention is an organic compound thin film composed of an extended conjugated quinone compound. As the extended conjugated quinone-based compound, parabenzoquinone, diphenoquinone, stilbenequinone, the compounds represented by general structural formulas 1 and 2, and derivatives thereof are effective. Is an organic compound having a π-electron system and easily excited. Structural formula 1
In the formula, Χ represents oxygen (O), sulfur (S), selenium (Se)
And specific examples thereof include derivatives such as dihydrofurandylidenebisbenzoquinone, dihydrothiophendiylidenebisbenzoquinone, and dihydroselenophendiylidenebisbenzoquinone. Structural formula 2 is dihydrothienothiophenediilidenebisbenzoquinone and its derivatives. In these structural formulas, R is hydrogen, methyl, ethyl, propyl, tertiary butyl, methoxy, ethoxy, halogen, phenyl, phenoxy, hydroxy (OH), mercapto (SH)
And an amino group. n is 1,2,3 and 4
It is.

The EC layer can be formed into a thin film by a method such as solution coating or vacuum deposition. The thickness of the EC layer is not particularly limited, but is usually about 50 to 5000 °. Of course, other ranges can be used.

In the present invention, the EC layer exists between the electrodes,
A more preferred structure is one in which the EC layer is sandwiched between the charge injection layers or the charge injection layer is stacked on the EC layer. As a material constituting the charge injection layer, a metal complex thin film,
An aromatic amine compound thin film, a semiconductor thin film and the like are effectively used. The metal complex thin film is effective as a good conductor of electrons, and can be used by being mixed with the EC layer in addition to the charge injection layer. The aromatic amine compound thin film can be effectively used as a hole injection layer and the semiconductor thin film layer can be effectively used as an electron or hole injection layer by doping impurities.

First, the metal complex is described as a complex compound formed from a metal and a ligand of an organic substance. Specifically, as a metal forming a complex, Al, Ga, Ir, Z
n, Cd, Mg, Pb, Ta, Tb, Eu, etc., and are not particularly limited. Organic ligands include porphyrin, chlorophyll, 8-hydroxyquinoline (oxin (Ox)), 5,7-dibromooxine, 5,7-diiodoxin, thiooxin, selenooxin, methyloxin, and phthalocyanine. , Salicylaldehyde oxime, 1
-Nitroso-2-naphthol, kuferon, dithizone,
Acetyl acetone or the like is used.

Further, the present invention does not prevent the use of an organic compound having a π-electron system which is easily subjected to external perturbation and which is easily excited with a metal complex. As the organic compound, for example, condensed polycyclic aromatic hydrocarbon, p-
Terphenyl, 2,5-diphenyloxazole, 1,4-bi
s- (2-methylstyryl) -benzene, xanthine,
Coumarin, acridine, cyanine dye, benzophenone, phthalocyanine, aromatic amine, aromatic polyamine, a compound having a quinone structure and forming a complex in an excited state, polyacetylene, polysilane, or the like is used.

These are used by mixing or laminating. Also,
Although the thickness is not particularly limited, it is usually 500 mm.
The following works well.

Various methods such as vacuum deposition, ion plating, sublimation, and coating can be effectively used as a method for forming a thin film.

As the semiconductor thin film, one kind or two or more kinds of inorganic semiconductor thin films are effectively used. These are also useful as amorphous, microcrystalline, polycrystalline, single crystal, or thin films in which amorphous and microcrystals are intermingled, as well as laminated thin films and artificial lattice thin films.

Semiconductor materials useful for forming these thin films include C, Ge, Si, Sn
Primary semiconductor such as, binary IV-IV semiconductor such as SiC, III-V semiconductor such as AlSb, BN, BP, GaN, GaSb, GaAs, GaP, InSb, InAs, InP, CdS, CdSe, Examples thereof include II-VI group semiconductor materials such as CdTe, ZnO, ZnS, and ZnSe, and multi-component compound semiconductor materials. Preferred material is Si (silicon)
To give a specific example, amorphous silicon (a-
Si), hydrogenated amorphous silicon (a-Si: H), microcrystalline silicon (μc-Si), polycrystalline silicon, single crystal silicon,
Hydrogenated amorphous silicon carbide (Si _1-X C _X : H), microcrystalline silicon carbide (μc-SiC), single crystal silicon carbide, amorphous silicon nitride, hydrogenated amorphous silicon nitride, microcrystalline nitride Silicon or the like is preferably used.

Here, the above-mentioned semiconductor thin film has a p-type or n-type property, or is doped to be p-type or n-type. The thickness is not particularly limited, and a sufficient function can be exhibited at 500 mm or less. The semiconductor thin film is formed by a photo CVD method, a plasma CVD method,
It is deposited by various physical or chemical thin film forming methods such as a CVD method, a molecular beam epitaxy (MBE) method, an organic metal decomposition method (MOCVD), an evaporation method, a sputtering method, and the like.

As the two electrode layers in the present invention, metal, alloy,
Metal oxide, metal silicide, conductive polymer materials, etc.
Alternatively, one or two or more of these stacked thin films are used. More preferably, a material having a high efficiency of injecting electrons or holes into the contacting thin film is selected.

Hereinafter, specifically, as an example, the first electrode layer, p-type a-SiC:
The element formed in the order of the H thin film layer and the charge injection layer composed of the metal complex, the EC layer composed of the extended conjugated quinone-based compound, the charge injection layer composed of the metal complex, and the second electrode layer are specifically exemplified and described. I will do it.

The first electrode layer is preferably made of an electrode material having a good hole injection efficiency into the p-type a-SiC: H semiconductor thin film. More specifically, as the electrode material, a metal compound thin film such as a metal, an alloy, or a metal oxide having a large electron work function, or a thin film obtained by laminating them is used. In addition, by making the first electrode light-transmissive, a structure is provided in which the discoloration of the EC layer can be recognized from the outside. Specific examples of the light-transmitting electrode material include thin films of metal oxides such as tin oxide (SnO ₂ ), indium oxide, and indium-tin oxide (ITO); , Au, Se, Pd, N
Metals and alloy thin films such as i, W, Ta, Te, and their laminated films, C
Suitable examples thereof include metal salt thin films such as uI, and laminated films thereof. Since the second electrode layer injects electrons into the EC layer made of an extended conjugated quinone-based compound, a metal or alloy thin film having a small electron work function, a laminated thin film thereof, or the like is generally used. Even more specifically,
Alkali metals such as Mg, Li, Na, K, Ca, Rb, Sr, Ce, alkaline earth metals, rare earth elements, alloys such as Mg-Ag, Cs-O-Ag,
A thin film such as Cs ₃ Sb, Na ₂ KSb, (Cs) Na ₂ KSb, or a laminated thin film thereof is suitable.

The device of the present invention comprises an electrode layer / EC layer / electrode layer / EC layer / electrode layer
/ EC layer / electrode ... may be multi-tiered. With this element structure, it is also possible to adjust the color tone and make the color multi-colored. Also, a large number of such elements may be arranged on a plane. The elements arranged on this plane can also exhibit various functions as color display members by changing the color tone of each element.

[Example 1] An ITO film was formed on a glass substrate to a thickness of 800 S
O ₂ film is formed to a thickness of 200 mm, a transparent conductive film (TCO) is formed,
This was the first electrode layer. Using a resistance heating vacuum evaporation method, an aluminum trisoxynate (Al (Ox) ₃ ) thin film, bisdihydrothiophenedylidenebisditertiarybutylbenzoquinone (in the structural formula 1, (X = S, R = t−
Butyl group, n = 2) thin film (referred to as bisthienylidene thin film), aluminum trisoxynate (Al (Ox) ₃ )
An EC layer sandwiched between charge injection layers was formed by depositing the thin films in the order of 100 °, 200 °, and 100 °, respectively. further,
On this layer, a Mg thin film was deposited by an electron beam evaporation method, and a second electrode layer of the present invention as shown in FIG.
An EC element was obtained. The area of the deposited Mg metal film is 3 mm square.

A voltage is applied to this light emitting element at a repetition frequency of 1 Hz from 0 →
The voltage was swept from 1.5V and then from 1.5 to 0V. It changes from pale green to very pale purple white at 1V or more, and this change in color tone can be obtained with good reproducibility even after 10,000 or more repetitions.
It was confirmed that the EC device of the present invention was excellent in stability and responsiveness.

[Example 2] Polythiophene obtained by electrolytic polymerization of thiophene on a gold electrode was used as a first electrode, and a bisthienylidene thin film and an Al (Ox) ₃ thin film were formed thereon in a thickness of 200 in this order.
An EC element as shown in FIG. 2 was obtained by forming in the same manner as in Example 1 except that an EC layer and a charge injection layer were formed by depositing {100} to form an EC layer, and an ITO layer was formed as a second electrode.

Also in the present EC device, discoloration was obtained with good reproducibility even after 10,000 or more repetitions as in Example 1, and it was confirmed that results were excellent in stability and excellent in response speed.

〔The invention's effect〕

The present invention provides an all-solid-state EC device having good stability and excellent response speed by using a color tone changing material composed of an extended conjugated quinone compound in the EC layer. As is clear from the embodiment, such an EC device according to the present invention has a high performance which could not be reached in the prior art.
An EC element, which is industrially extremely useful as a display member or the like.

[Brief description of the drawings]

1 to 3 are explanatory views showing an example of the layer configuration of the device of the present invention. In the figure, 1,11 ... a substrate such as a glass plate, 2,12, ... a first electrode layer made of TCO, metal, conductive polymer material, etc., 3,13 ... made of an extended conjugated quinone compound EC layer, 4,14..., Second electrode layer made of TCO, metal material, etc., 15, 15 ′... Metal complex, charge injection layer made of semiconductor thin film layer.

Claims (1)

(57) [Claims] At least one electrode contains an extended conjugated quinone-based compound between two electrode layers, each of which is light-transmissive, and is sandwiched by a charge injection layer or is present in a charge injection layer. An electrochromic device having a color tone changing layer that is stacked.