JPS6186735A - Electrochromic element - Google Patents

Abstract

PURPOSE:To obtain an electrochromic (EC) element having an increased response speed and a prolonged life by interposing an insulating layer consisting of laminated thin ZrO2 and SiO2 films between anode and cathode side EC layers. CONSTITUTION:The 1st transparent electrode 2 is formed on a transparent substrate 1, and an Ir(OH)2 film as an anode side EC layer 3 is formed on the electrode 2. An insulating layer consisting of laminated two layers is formed on the layer 3 by laminating a thin SiO2 film 4b and a thin ZrO2 film 4a. A cathode side EC layer 6 such as a WO3 film is formed on the film 4a, and the 2nd electrode 5 of transparent or translucent Au or the like is formed on the layer 6. Since the insulating layer is formed by laminating the SiO2 film 4b having high electron blocking property and stability and the ZrO2 film 4a having high ionic conductivity, an EC element having an increased response speed and a prolonged life is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an electrochromic device that utilizes an electrochemical coloring/decoloring phenomenon, that is, an electrochromic phenomenon.

Electrochemically quenched dye elements, or electrochromic devices, utilize such electrochromic phenomena.
For example, it can be applied to numeric display elements, X-Y matrix displays, optical shutters, aperture mechanisms, etc. Classified by material, it can be divided into liquid discs and solid types, but the present invention is particularly applicable to all-solid type electrochromic elements. It is related to.

[Background of the invention]

Two structural examples of electrochromic elements utilizing the electrochromic phenomenon are shown in FIGS. 2 and 3.

These figures are electrified.

This figure shows the general structure of the element.

The electrochromic device shown in FIG. 2 includes a transparent substrate 1, a first electrode 2 formed from a transparent conductive film, an electrochromic layer 3 formed from a coloring layer on the anode side, an insulating layer 4 made of a dielectric film, The second electrode 5 made of a conductive film is sequentially laminated.

Furthermore, the electrochromic element shown in FIG.
Between the insulating layer 4 and the second electrode 5 in the structure shown in the figure,
Further, a second electrochromic layer 6, which is a coloring layer on the cathode side, is laminated.

In the above structure, the substrate 1 is generally formed of a glass plate, but this is not limited to a glass plate, and may be any colorless and transparent plate such as a plastic plate or an acrylic plate. Also, not under the first electrode 2,
It may be provided on the second electrode 5, or may be provided on both sides depending on the purpose (for example, to serve as a protective cover). However, depending on these cases, it is necessary to make the second electrode 5 a transparent conductive film, or to make both the electrodes on both sides transparent conductive films. If both electrodes are transparent, a transparent dust element can be created. The insulating layer 4 may be made of not only a dielectric but also a solid electrolyte or the like.

The transparent conductive film is an ITO film (indium oxide In2
O3 doped with tin oxide 5n02), NESA film, etc. are used. The electrochromic layer 3, which is the coloring layer on the anode side, has conventionally been made of tetratrioxide (CrzOs), iridium hydroxide (Ir(OH)2), nickel hydroxide (N
t(oH)z ), etc. The insulating layer 4 made of dielectric material is made of zircon dioxide (Zr02), tantalum pentoxide (Ta205), silicon oxide (810,5
It is formed using an oxide such as i02) or a fluoride such as lithium heptadide (LiF) or magnesium fluoride (MgFz). In addition, the electrochromic layer 6, which is the coloring layer on the cathode side, is made of tungsten oxide (WO2#WO3), molybdenum oxide (Mo02
It is formed using ゜Mo03), vanadium pentoxide (V2O3), etc.

An electrochromic element with such a structure has a first
By applying a voltage between the electrode 2 and the second electrode 5, an electrochemical reaction occurs, resulting in coloring and decoloring. It is generally said that this coloring mechanism is based on formation of bronze by double injection of cations and electrons into the electrochromic layer 6, for example. For example, when using WO,5 as an electrochromic substance, the following (1)
The oxidation-reduction reaction expressed by the formula occurs, resulting in color.

WO3+ xH+ + xe−-: HJCWO3(1
) According to formula (1), tungsten bronze HxWo
5 is formed and colored, but if the applied voltage is reversed at this point, it becomes a decolored state. In an electrochromic element, such a reaction of formula (1) is caused by protons H+ being supplied by an insulating layer inside the element and causing coloration.

[Problems that the invention attempts to solve]

Such electrochromic elements still have problems in terms of response speed and lifespan.

[Purpose of the invention]

The present invention aims to provide such an electrochromic element that has better response speed and longer life than conventional electrochromic elements.

[Summary of the invention]

The electrochromic device according to the present invention is characterized by a first electrode made of a conductive film, an electrochromic layer which is an anode side coloring layer, an insulating layer made of a dielectric, and a second electrode which is a cathode side coloring layer. In an electrochromic element having an electrochromic layer and a second electrode made of a conductive film, the insulating layer is a two-layer stacked type, and the two layers are made of a ZrO layer and a S loz layer. It is in the fact that

〔Effect of the invention〕

ZrO2 film is quite good as the so-called insulating layer (which can be considered as a solid electrolyte) of electrochromic elements, but the performance of electron f4 and king is lower than that of 8102 film, and furthermore, it is not stable when used as a single film. The quality (lifespan) is also bad. On the other hand, although the 5to2 film has good electron blocking performance, it has poor ionic conductivity, and using only a single film deteriorates the characteristics of the electrochromic device.

The electrochromic device according to the present invention has an insulating layer made of a laminate of ZrO2 film and SiO2 film as described above, thereby compensating for the above-mentioned drawbacks of these thin films, which could not be achieved with a single film of each film alone. By stacking layers, we can bring out the performance and provide electrochromic elements that are far superior to conventional ones.

[Embodiments of the invention]

An embodiment of the electrochromic element according to the present invention is shown in FIG. Since the basic structure of this electrochromic element is the same as that shown in FIG. 3, the same parts as shown in FIG. 3 are designated by the same reference numerals.

In the illustrated embodiment, 1 is a transparent substrate, 2 is a first electrode made of a transparent conductor, 3 is a first electrochromic layer which is a coloring layer on the anode side, and 6 is a coloring layer on the cathode side. Reference numeral 2 indicates an electroconductive layer, and reference numeral 5 indicates a second electrode made of a conductive film.

The insulating layer disposed between the first and second electrochromic layers 3 and 6 includes a ZrO2 film 4a and a 5to2 film 4.
It is composed of b.

In the above structure, the first electrochromic layer 3 and the second electrochromic layer 6 may be reversed. Further, in the insulating layer formed by laminating the ZrO2 film 4a and the 5to2 film 4b, it is preferable that the ZrO2 film 4a side is in contact with the coloring layer on the cathode side. Further, the thickness of each film is 1000 to 4000× for the ZrO2 film.

The sio2 film is preferably between 30 and 500X.

Example 1 On a transparent substrate 1, an electrode 2 made of an ITO film having appropriate extraction electrode parts and lead parts was formed. Introducing a gas with a ratio of H2 gas and 02 gas of 1:2,
．． Under a pressure of 4 Torr, the first electrochromic layer 3, which is a coloring layer on the anode side, is formed on the above electrode 2 using a reactive Takaoka wave A layer containing metal Ir as a tarduct.
As a result, an I r (OH) 2 film 500X was formed. Next, as the insulating layers 4m and 4b, S
The iO2 film was 1001. 28001 ZrO2 films (respectively, 5i02.ZrO2 was used as the vapor deposition material) were formed. 40,001 WO3 films were formed as the electrochromic layer 6, which is a coloring layer on the cathode side, and a semi-transparent Au electrode was attached as the second electrode 5 on top of these films.

The electrochromic device formed in this way has two
．． With constant voltage drive of 2V, the response speed until ΔC0D0.3 is 150m5ec, and the lifespan is 106 times.
Significant improvements were seen in response speed and lifespan.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of an electrochromic device according to the present invention, and FIGS. 2 and 3 are cross-sectional views showing the general structure of the electrochromic device. 1... Substrate, 2... First electrode, 3...
- Electrochromic layer, 4... Insulating layer, 5-... Second electrode, 6... Electrochromic layer, 4a, 4b... Insulating layer. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] A first electrode made of a conductive film, an electrochromic layer which is an anode side coloring layer, an insulating layer made of a dielectric film, a second electrochromic layer which is a cathode side coloring layer, and a second electrochromic layer made of a conductive film. An electrochromic device comprising two electrodes laminated in sequence, characterized in that the insulating layer is a lamination of a ZrO_2 film and a SiO_2 film.