JPS6240432A - Whole solid-state electrochromic element - Google Patents

Abstract

PURPOSE:To maintain a water amount necessary to operating the EC to almost a constant value without affecting a direct effect of an atmosphere surrounding the element by coating the surface of the whole solid-state EC element with a plasma- polymerized film. CONSTITUTION:The titled element is the whole solid-state electrochromic element having a laminated part obtd. by laminating the transparent electroconductive film, the 1st film, the solid electrolyte film, the 2nd film and the electroconductive film in order, and constituted of the substance generating the electrochromism reaction which colors any one of the 1st film or the 2nd film with the oxidation and colors an another film with the reduction. The whole solid-state EC element is coated the laminated part 4 and the substrate 41 with the plasma-polymerized film 5 of an org. compd. The org. compd. of forming the plasma-polymerized film preferably comprises a methane, an acetylene, a furan, an acrylic acid and a tetrafluoroethylene. The prescribed film contg. many of a crosslinked structure and having a very small space free volume and a water permeability suitable to use for the whole solid-state EC element is obtd. by plasma-polymerizing the prescribed org. compds. The thickness of the plasma-polymerized film is preferably 10-10,000mum considering the water permeability thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an all-solid-state electrochromic (hereinafter referred to as EC) element that electrochromically changes color and fades upon application of voltage.

[Prior art and its problems]

EC elements are non-emissive elements like liquid crystals, but they have characteristics such as wide visibility, memory function, and the ability to be driven with low voltage9, making them suitable for use as display elements. Applications are expected.

Further, as a light control body, for example, it is possible to control external light according to the amount of solar radiation.

EC elements are roughly classified into molten gI type and solid type, and the amount of solution is one in which an electrolytic solution is filled between an EC membrane and an electrode facing it. On the other hand, the solid type replaces the above electrolyte with a solid electrolyte, and has the drawbacks of the solution type, such as difficulty in creating a curved structure 9 reflection type structure, and liquid scattering when broken.

It is said that everything can be overcome.

FIG. 2 is a cross-sectional view schematically showing the general structure of an all-solid-state EC element. This element is placed on a substrate glass 11,
Transparent conductive film 12 made of indium-tin oxide (hereinafter referred to as ITO). Nickel oxide (NO
) film 13. Tang pentoxide fv (T
axes) membrane 14. It has a five-layer stacked structure including a film 15 of tungsten oxide (W(h)), which is a reduced coloring substance, and an upper conductive film 16 made of ITO or aluminum (Ae). Films are formed by methods such as swabbing and ion blating.

The EC element having the structure shown in FIG.
If we add a potential difference between 6.

WOs + 'H++ xe-,: As shown by the formula HJWOj, proton (H') and electron (e-)
It is said that a reaction due to the double injection and release of ions proceeds in the WO3 and NiO films, repeating coloring and decoloring. Here, protons are generated by decomposition of water contained in the TazOs film 14 and the WO3 film 15.

It is believed that this will be supplied.

In other words, the characteristics of an all-solid-state EC device are affected by moisture outside the device. That is, when an element is placed in a low-humidity atmosphere or a high-temperature atmosphere, moisture in the element decreases, which may lower the color density.

JP-A No. 60-21030 discloses that silicon dioxide (8+Ot) or nitroxysilicon (81
An EC device has been disclosed in which a film of @N4) is formed by a method such as plasma CVD, and then a glass plate is bonded to the top of the device using an organic adhesive. However, in order to form a film, the entire device is heated to 10"
10')-/L/(torr)■ Since the EC element must be kept in a vacuum, the moisture in the EC element will dissipate, and the EC element may become completely inoperable after the 5iOj, 8i, or N4 film is formed.

In addition, S.07 or S.3N4 has a high ability to prevent moisture permeation, so they should be taken out into the atmosphere after treatment.

There is a problem in that the probability that a malfunctioning element will recover its operation is not high.

[Problems to be solved by the present invention]

Therefore, the inventors conducted four types of studies in order to solve the problems of the above-mentioned all-solid-state EC elements.

As a result, even if it covers an all-solid-state EC element.

Considering the formation of a buffer M that can block the transmission of changes in the usage environment to some extent, the buffer layer is made of:

We have reached the conclusion that it is desirable to have the following properties: The buffer layer prevents moisture in the EC element from scattering out of the EC element under high temperature or low humidity atmospheres, and prevents moisture from entering the element under low temperature and high humidity atmospheres. The results show that it is desirable to have a material C that has a certain degree of blocking ability against moisture permeation so that moisture can be taken in, and that can elastically absorb deformation caused by the operation of the element. In this way, the present invention was accomplished.

[Means and effects for solving the problems] The present invention has the following features:
A transparent conductive film, a first film, a solid electrolyte film, a second film on the substrate,
It has a laminated part formed by sequentially disintegrating conductive films, and has a first film and a second film.
One of the membranes is colored by oxidation and the other is made of a substance exhibiting an electrochromic reaction that turns blue by reduction, and the surface of the element is coated with an organic compound O plasma silica film. This is an all-solid-state electrochromic device with all the following characteristics.

An example of the structure of an all-solid-state EC device according to the present invention will be explained with reference to FIG.

The substrate 41 is usually a plate made of transparent glass, and its shape may be a flat plate or a curved plate.
It serves as a coloring/decoloring display surface of the device.

The transparent conductive film 42 constituting the laminated portion 4 is transparent and has a transparent conductive film 4e! is transmitted through the first membrane 43. This allows the state of coloring and decoloring of the second pattern 45 to be observed from the substrate 11 side. Further, the first film 43. One of the 10,000 parts of the second film 45 is made of a substance that becomes colored when exposed to acid, and the other part is made of a substance that becomes dark when it is reduced with carbon.

The material constituting the transparent conductive film 42 is ITO.

SnO2, etc. can be used. The materials constituting the first and second films include N i O, tr02, Rb02, etc., which are colored by oxidation, and WO3, MoOx V2, which are colored by reduction.
05. etc. can also be used. The solid bottom solute 1 44 is an inert material for transferring protons and electrons between the first membrane and the second membrane. Vx as a concrete substance constituting the solid N solution,
Ta, 05.0r203. A conductive film 46 as an electrode is provided on the second film O, which may be made of SiOz or the like,
Between the transparent conductive film 42, a first film, a solid Go1 decomposition film,
An electric field is applied to the second film.

The material for forming the conductive film 7I6 is the transparent conductive film 4.
2 may be used, or an opaque material such as A(1, Al, Sn, etc.) may be used. In the case of a transparent material such as ITO, a transmissive all-solid-state EC element, Ae, etc. If it is made of an opaque substance, it becomes a single reflection type EC element.

The all-solid-state EC device according to the present invention is formed by coating the laminated portion 4 and the substrate 41 with a plasma polymerized film 5 of an organic compound. Methane (CH4) is used as an organic compound for forming a plasma polymerized film.

Acetylene (02H-), furan c c, u, o >
, acrylic acid (OH, = CHCOOH), tetrafluoroethylene (F2c = cFz), etc. are commonly used.If these compounds are plasma polymerized,9 ordinary synthetic polymers can be formed into a thin film by a method such as Nupinar coating. It contains more crosslinked structures than those molded into polysilicon, has an extremely small free space volume, and has moisture permeability suitable for all-solid EC devices.For example, commercially available polysalt f
The water permeability is approximately 1/10' times higher than that of a membrane formed by dissolving hibinyl in a solvent and using a spinner coating method.

The thickness of the plasma polymerized film is preferably about 10 to 10,000 nm in consideration of moisture permeability and the like.

If the thickness is less than iQnm, moisture will easily pass through.

If it exceeds 10,000 nmi, the moisture permeation blocking ability becomes too large. In addition, plasma polymerization of 110000n or more @
This is not preferable because the film in the process of being formed is exposed to a plasma space for a long time, which tends to induce changes in the chemical composition of the formed film and also causes cracks to occur.

A method for forming a plasma polymerized film is, for example, as follows. First, the vapor of an organic r-arsenite for film formation is
A predetermined input is applied from a high frequency power source to a vacuum container filled with water at a pressure of about 1 to 18 (torr), and electrons and radicals are generated in the container.

A polymer film made of organic compounds is formed on the surface of the

Cover the laminate. During plasma polymerization film formation, the temperature of the laminated portion only rises to about 1001°C.

If the pressure is 0.05 ) -3 or higher and the stacked EC device is not placed in a low pressure state as in the plasma CVD method, it will normally operate as expected. Also.

Even if the moisture in the laminated portion dissipates during the formation of the plasma polymerized membrane, the plasma polymerized membrane will allow a moderate amount of moisture to pass through.
The operation of the element is restored.

Also, what are the chemical structures and physical properties of plasma polymerized films?

This is different from the case using general polymerization methods, and it is difficult to specify it as a fixed method. C these are.

Different types of offal are produced depending on the type of organic compound and conditions such as pressure. As mentioned above, the gas pressure during plasma polymerization is preferably in the range of 0.01 to 1 Torr.

If it is less than 0.01)-L, the film formation rate is low; ) - L or more, the density of the obtained film becomes low, resulting in inconvenience.

Furthermore, during plasma polymerization, an inert gas such as helium or argon, a halogen gas such as fluorine, hydrogen gas, or the like may coexist in the container. In this case, the resulting material has a high degree of crosslinking, and by changing the amount of gas mixed in, the water permeability and ejection ability can be adjusted over a wide range.

Between the transparent conductive legs 42 and the conductive film 46 of the all-solid-state EC element and D
/ic! When a total pressure is applied and the voltage is changed, a solid electrolyte W
, the entire membrane 46 is 1ffi, and protons and electrons are exchanged between the 141st and 2nd membranes, fillN.

The second film changes color and performs D operation as an EC element.

At this time, if the device is placed in a high temperature, low pressure or (low humidity) atmosphere, the plasma polymerized film will cause υ.

On the other hand, water dispersion from the laminate is moderately prevented.

If placed in a high humidity atmosphere, moisture will prevent O from accumulating. As a result, even if the atmosphere changes, the amount of moisture clouding in the laminated portion remains approximately constant.

[Effects of the present invention] All-solid-state EC element - The entire surface is coated with a plasma polymerized film, which eliminates moisture necessary for EC operation.

It is possible to maintain a constant value without being directly affected by the atmosphere around the element. Therefore, the all-H, r1-body EC Shiko according to the present invention is not affected by the surrounding atmosphere.

Changes in color and fading (decolorization) can be performed under stable operation with a nearly constant rate of discoloration.

〔Example〕

The present invention will be explained in detail below.

First, the main parts of the plasma polymerization apparatus used in the examples are shown in FIG. 5 in a private diagram. The vacuum container 2 consists of a jar 21 made of Galanu and a metal stand 2 that consists of the bottom of the jar 21.
The connecting portion between the two parts 4 and 9 has a structure that does not allow gas to pass through easily.

The jar 21 is a bottomless glass container with a height of about 501 m and a body diameter of about 30 cm, having a protrusion 22 with a diameter of about 71 at the top.

A gas introduction passage 29 such as ArJ(e, LL, etc.) is provided at the tip of the protrusion 22. A copper plate as an electrode 23 for applying a high-frequency electric field is wound around the center of the protrusion 22. It is.

On the other hand, the metal base 24 has an introduction passage 27 for introducing an organic compound as a raw material gas, an exhaust passage 28 for discharging the gas in the jar 21, and a grounding terminal 25.

Furthermore, an EC element is mounted on the upper surface of the metal base 24, and a vacuum pump (not shown) connected to the discharge passage 28 is used to
Evacuate the air in the vacuum container. next.

While exhausting air with a vacuum pump, an organic r-hyde compound is introduced from the introduction passage 27, and the pressure in the vacuum container is adjusted to a predetermined pressure.

When polymerization is carried out in the coexistence of other gases such as inert gases, the entire gas introduction passage 29 is used.

In this state, a high frequency power source (not shown) is connected between the droplet f'@23 and the metal fitting 25 to bring the inside of the vacuum container into a plasma state. A plasma polymerized film is formed on the surface of the EC element 31, which is placed vertically on the sample stage 26. After a predetermined period of time has elapsed, the application of the high frequency electric field is stopped, air is introduced into the vacuum container, and the EC element is taken out.

Example 1 Methane as an organic compound was introduced into a vacuum container, and the pressure in the container was set to 0.2 Torr.

A plasma polymerized film of methane was formed on the element at a power of 50 watts and a frequency of 13.9 between the electric box and the metal fittings.

This is followed by introducing air into the container, opening the jar, and
The metal frame to which the C element was pasted was turned upside down, and plasma polymerization was performed again under the same conditions for 15 minutes. As a result, an all-solid-state EC device coated with a uniform plasma polymerized film having a thickness of about 500 OA was obtained.

Example 2 Introduce 003 torr of methane into a vacuum vessel.

Example 1 except that hydrogen was then further introduced and the pressure inside the container was set to 0.2 Torr. Under the same conditions as above, an all-solid-state EC device was obtained in which the surface of the EC device was coated with a plasma polymerized film having a thickness of about 50 OA.

Example 3 Plasma polymerization was carried out under the same conditions as in Example 1, except that acetylene was used as the raw material gas and the high frequency electric field was applied for 5 minutes in total. As a result, an all-solid-state EC device coated with a plasma polymerized film having a thickness of about 5,000 mm was obtained.

Example 4 Furan as raw material gas? Plasma polymerization was carried out under the same conditions as in Example 1, except that the two high-frequency electric fields were used for 1 hour and 10 minutes in total. An all-solid-state EC device coated with a plasma polymerized film having a thickness of about 420 OA was thus obtained.

Example 5 Acrylic acid was used as the raw material gas, and the pressure inside the container was set to 0.
The same conditions as in Example 1 were obtained except that the setting was 1 torr.

Example 6 Tetrafluoroethylene as raw material gas? Plasma polymerization was carried out under the same conditions as in Example 1, except that the high-frequency electric field was applied for 10 minutes.

FIG. 1 shows a schematic partial cross-sectional view of the all-solid-state EC device of each of the above embodiments. The EC element is placed on the glass substrate 41,
2000A thick ITO film 42° Ta2O, film 44. 1500mm thick AONiO film 45 and 2000mm thick
ITOIIit [46] were sequentially laminated by vacuum vapor deposition to form a laminated part. In addition, the size of the laminated part is 3.5
X 3.5 ff. The all-solid-state EC device of each example is one in which the above EC device is coated with a plasma polymerized film 47.

Next, the coloring/decoloring characteristics of the all-solid-state EC element Q of each example are compared to the uncoated conventional example (comparative example 1) and the 8i0.
The evaluation was made in comparison with that coated with (thickness: 2000A) (Comparative Example 2).

The evaluation conditions were 2.The ambient temperature was constant at 25℃ and the humidity was 80%.
, 55%, and 20% three-stripe atmosphere for one day each. During the holding, an AC voltage of ±2Y, 0.2Hz was applied to the ITO.
The charge was applied between i42 and 46 to cause coloring and decolorization, and at this time, the amount of charge injected per unit area of the device was determined. The results are summarized in the table.

When the elements of each example were placed in an atmosphere with a humidity of 55%,
When placed in an atmosphere with humidity of 80% and 20%, the amount of charge injected is 58 to 2.4 millicoulombs (mC)/c-F.
It is within the A range and does not change significantly. However, in Comparative Example 10, f3 r Q ? Since moisture is scattered from the device during film formation and is not replenished from the outside thereafter, the amount of injected charge is extremely small, and therefore the amount of coloring cannot be of a value that can be used in practice.

] At a comparative meeting, when the humidity was changed from 55% to 80%,
Although the amount of injected charge increases to 6.0 mQ/cd.

When the humidity is lowered to 20%, it decreases to 2.0 mC/d. In other words, it can be seen that the coloring and fading characteristics are affected by removal and humidification, especially by dehumidification.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing an example of the structure of an all-solid-state electrochromic device according to the present invention, and FIG. 2 is a cross-sectional view of a conventional all-solid-state electrochromic device.
FIG. 5 is a cross-sectional view schematically showing a plasma polymerization apparatus used in Examples. 2...Vacuum container, 4...Lamination part. 11, di... board. 42...Transparent conductive film, 43...First film. 44...Solid electrolyte membrane, 45...Second complaint. Roganjin Co., Ltd. Toyota Central Research Institute

Claims (3)

[Claims] (1) It has a laminated part formed by sequentially laminating a transparent conductive film, a first film, a solid electrolyte film, a second film, and a conductive film on a substrate, and one of the first film and the second film is oxidized. An all-solid-state electrochromic device comprising a substance exhibiting an electrochromic reaction in which one color is colored and the other is colored by reduction, the device being characterized in that the surface of the device is coated with a plasma-polymerized film of an organic compound. chromic element. (2) The above organic compounds include methane, furan, acrylic acid,
The all-solid-state electrochromic device according to claim (1), characterized in that it is any one of tetrafluoroethylene. (3) The organic compound is an organic compound mixed with an inert gas such as helium or argon, a halogen gas such as fluorine, or hydrogen.
) The all-solid-state electrochromic device described in item 1.