JPH03119325A - Production of electrochromic element - Google Patents

Abstract

PURPOSE:To obtain the EC element having a high response speed by forming insulating layers initially at a high substrate temp., then at a low temp. CONSTITUTION:The lamination of the insulating layers 4 is executed at the high substrate temp. then at the low substrate temp. at the time of forming the boundary with a 1st electrochromic layer 3. Namely, the insulating layers 4 are formed at the high substrate temp. in the initial period of the vapor deposition and are thereafter formed at the low substrate temp. The high substrate temp. refers to 90 to 180 deg.C, more preferably 90 to 120 deg.C. Advantage is taken out the characteristics at the time of the film formation at the respective temps. and simultaneously, the drawbacks in the film formation are eliminated by changing the substrate temp. at the time of the vapor deposition of the insulating layers 4 in such a manner. The EC element which has the excellent response speed and the good adhesive strength between the layers is obtd. in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for manufacturing an electrochromic (hereinafter referred to as EC) element, and more particularly to a method for manufacturing an EC element characterized by a method for forming an insulating layer.

(Prior art) EC phenomenon is a phenomenon in which the light absorption range of a substance changes and the substance becomes colored or decolored due to the induction of reversible electrochemical reactions (oxidation/reduction reactions) that occur when voltage is applied. say.

Electrochemical adsorption/quenching molecules utilizing such EC phenomenon are called E.
It is called a C element and is expected to be applied to, for example, variable ND filters, anti-glare mirrors, numeric display elements, XY matrix displays, optical shutters, aperture mechanisms, etc.

As shown in FIG. 2, the conventional EC element described above generally has a first electrode 2 made of a transparent conductive film on a transparent substrate 1, and an insulating layer made of a first ECC84 dielectric film which is a colored layer on the anode side. 4. The second ECC 50, which is a colored layer on the cathode side, and the second electrode 6 are sequentially laminated.

In the above structure, the substrate l is generally formed of a glass plate, but is not limited to glass, and may be a transparent plastic plate such as an acrylic plate, a polystyrene plate, or a polycarbonate plate.

The -EC layer 3, which is a colored layer on the anode side, is formed of, for example, iridium oxide (Ire), nickel oxide (Nip), chromium trioxide (Cr*0□), or the like. The intermediate insulating layer 4 made of a dielectric material is made of, for example, tantalum pentoxide (T
a*Os), silicon dioxide (SiO□), or a fluoride such as lithium fluoride (LiF), magnesium fluoride (Mgh), etc.

The second EC layer 5, which is a colored layer on the cathode side, is made of tungsten trioxide (WOs), tungsten dioxide (WO□), molybdenum dioxide (MOOI), molybdenum trioxide (M
oOs), vanadium pentoxide (vtos), etc.

The all-solid-state EC element with the above structure has a first electrode 2
By applying a voltage between the material and the second electrode 6, an electrochemical reaction occurs in the EC element, and the light wavelength range of the substance changes, causing coloring and decoloring.

Such a coloring mechanism is, for example, the hydrogen ion H of ECC50.
It is said that bronze is formed by double injection of + and electron e-.

For example, when WO2 is used as the EC substance, the following (
1) Redox reaction WOs + xH"+ xe--e H1lWO3(1
) formed in accordance with Ngsten Bronze H, WO
3 turns blue. On the other hand, if the applied voltage is reversed here, a colorless state is achieved.

In the reaction shown in equation (1), in an all-solid-state EC element, hydrogen ions H' are supplied by an insulating layer inside the element and the element is colored.

In the process of forming the conventional EC element as described above,
The insulating layer 4 was laminated on the -EC layer 3 under certain conditions by vacuum evaporation or the like.

(Problems to be Solved by the Invention) In the conventional EC element as described above, when the surface shape of the -th EC layer 3 is uneven as shown in Fig. 2 and is thermally unstable, (1) Since the surface of the layer 3 is uneven, if the insulating layer 4 is formed at a low temperature, the interface between the two will not be properly bonded, resulting in deterioration of the characteristics of the EC element.

(2) If the insulating layer 4 is formed at a high temperature, the eyebrows 3 are thermally unstable, resulting in deterioration of the characteristics of the EC element.

Due to this problem, a sufficient response speed as an EC element could not be obtained.

Specifically, the -EC layer 3 is made of IrOx by an anodic oxidation method.
In the case where the insulating layer 4 is a Ta2es film formed by electron beam method, 80
When heat of ℃ or more is applied intermittently to the IrOx film for 5 minutes or more, a part of the Ir(1+ film is gradually reduced and becomes metallic, causing deterioration of the characteristics of the EC element.The extent of this will depend on the temperature The higher the temperature and the longer the time, the larger the temperature becomes.In order to solve this problem, the substrate should be cooled and kept at 80° C. or lower.

However, when forming the interface between the Ir(1+ film 3 and the insulating layer 4) at the beginning of vapor deposition, the surface shape of the IrOx film is complex, so if the substrate temperature is below 90°C, the energy imparted to the vapor deposited particles is small. However, there is a drawback that the adhesion between the films decreases, creating spaces, etc., making it difficult to transport the ions necessary for coloring and decoloring, resulting in deterioration of characteristics.

As described above, when the insulating layer 4 is formed under the condition of a constant substrate temperature, there is a drawback that the response speed as an EC element is insufficient.

Therefore, an object of the present invention is to solve the above-mentioned problems in forming an insulating layer in the conventional example, and to provide an EC element having good characteristics without deterioration of the first EC layer during film formation. ..

(Means to solve the problem) The above objects are achieved by the present invention as described below.

That is, the present invention comprises a first electrode made of a conductive film on a substrate, an -EC layer which is a colored layer on the anode side, an electronic insulation layer of a good ionic conductor made of a -dielectric film, and a colored layer on the cathode side. In a method for manufacturing an EC element in which a certain second EC layer and a second electrode made of a conductive film are sequentially laminated, the lamination of the insulating layers is
EC characterized in that the interface with the -EC layer is formed at a high substrate temperature, and thereafter at a low substrate temperature.
This is a method for manufacturing an element.

(Function) As mentioned above, by changing the substrate temperature during vapor deposition of the insulating layer, the characteristics of film formation at each temperature are utilized, and at the same time, the defects in film formation are eliminated, thereby making the process more efficient than conventional methods. EC with excellent response speed and good adhesion between each layer
An element is provided.

(Preferred Embodiments) Next, the present invention will be described in more detail by citing preferred embodiments.

As shown in FIG. 1, the EC element manufactured by the present invention has the same structure as the conventional example, and each component is a transparent substrate l, a first electrode 2, a -th EC layer 3, intermediate insulating layer 4,
The second ECC 50, second electrode, etc. are also formed and laminated using the same materials and methods as in the conventional example.

The present invention is characterized by the method of forming the insulating layer. In the step of forming the insulating layer 4, when forming the interface with the -EC layer, that is, in the early stage of vapor deposition, the insulating layer is formed at a high substrate temperature. 4 is formed, and the subsequent formations are performed at a low substrate temperature. Here, the high substrate temperature is 90°C to 180°C, more preferably 90°C to 120°C.

Further, the time period for which the high substrate temperature is maintained needs to be short because if it is too long, the EC element will suffer thermal deterioration.

Preferably, the time is about 0.5 minutes to 5 minutes.

As described above (after forming an insulating layer at a high substrate temperature at the interface with the -EC layer), the remaining insulating layers are formed at a low substrate temperature. Here, the low substrate temperature is preferably about 40°C to 80°C. The temperature is more preferably 40°C to 60°C.

Further, in the above, the insulating layer deposited at a high substrate temperature preferably has a thickness of about 1 to 10% of the entire insulating layer.

Further, the gradient of the substrate temperature with respect to the thickness of the insulating layer may be reduced linearly or stepwise. Preferably, the substrate temperature is set using a temperature controller.

FIG. 1 is a diagram schematically showing a cross section of an EC element in which the insulating layer 4 is formed by changing the substrate temperature in the present invention. 4a is a part of an insulating layer formed at a high temperature to form a good bonding surface with the -EC layer 3 having an uneven surface, and within a time period that does not cause thermal deterioration; 4b is a part of the insulating layer formed on the -EC layer 3 having an uneven surface This is the remaining portion of the insulating layer formed at a low temperature that does not cause thermal deterioration.

(Example) Next, the present invention will be described in more detail with reference to conventional examples and examples.

Conventional Example 1 An IrL film was formed from a metal iridium film by anodic oxidation using the apparatus shown in FIGS. 3 and 4.

In Fig. 3, 31 is a metal iridium film with a thickness of 400 Å formed on a glass substrate with ITO by the electron beam method (the film thickness is usually 500 Å or less, and 300 Å or less in order to create the film without peeling). (preferably 400 people)
32 is a reference electrode 5EC133 is a platinum electrode, 34
is O, OIN 1(, SO, aqueous solution.

The anodic oxidation cell as described above is driven by a glass cell driving device as shown in FIG. 4, and the metal iridium film 31 is anodized to form an IrOx film. 45 is a potentiostat, and 46 is a potential sweeper.

As shown in Table 1 below, the amplitude of the potential is increased stepwise until the speed is 0. IrO was swept at IV/sec.
x film 3 was created.

Furthermore, as an insulating layer, Ta, 0. The film 4 was heated to a substrate temperature of 100°C.
The film was deposited to a thickness of 3,000 people at a deposition rate of 1.5 people/sec. Next, as the second EC layer 5, a WO2 film with a thickness of 4.000
The all-solid-state EC device of Conventional Example 1 shown in FIG. It is.

When a DC voltage of +1.5V was applied between the first electrode 2 and the second electrode 6 to this element with the first electrode 2 as a reference, a concentration change of Δ0D=0.43 was observed at 250 m5ec. .

The Ir(1+ film of the above EC element) was exposed to heat at 100°C for more than 30 minutes, resulting in deterioration in characteristics such as part of the film being reduced and becoming metallic, resulting in insufficient response speed as an element. There wasn't.

Conventional Example 2 The AEC element shown in FIG. 2 was produced in the same manner as in Conventional Example 1 except that the substrate temperature was 50° C. when forming the insulating layer.

When a DC voltage of +1.5V was applied between the first electrode 2 and the second electrode 6 to this EC element with the first electrode 2 as a reference, a concentration change of Δ0D=0.49 occurred at 250 m5ec. Indicated.

In addition, because the substrate temperature was low when forming the interface between the insulating layer and the Ir(1+ film), the adhesion between the films was weak and transport of ions was difficult, resulting in insufficient response speed as an element. Ta.

Example 1 Similar to Conventional Example 1, Ir as the -EC layer is formed on the first electrode 2.
Ox film 3 was created. On top of that, as shown in Figure 1, I
As the insulating layer 4a forming the interface with the rOx film 3, Ta
*Os film 4 was deposited at a substrate temperature of 120°C and a deposition rate of 1.5 people/s.
It was deposited for 1.5 minutes under the conditions of
An a*Os film 4a is stacked. Next, the insulating layer 4b forming the interface with the second EC layer 5 is deposited on the substrate at a temperature of 70°C and a deposition rate of 1.
Deposited to a thickness of 2,865 people under the conditions of 5 people/see,
An insulating layer 4 having a total thickness of 3,000 layers was laminated by an electron beam method, and then the same procedure as in Conventional Example 1 was carried out to produce an EC element of the present invention.

When a DC voltage of +1.5V was applied between the first electrode 2 and the second electrode 6 to this EC element with the first electrode 2 as a reference, a concentration change of Δ0D=0.65 was observed at 250 o+sec. , the response speed was improved.

Example 2 In the same manner as in Example 1, IrO+ is used as an insulating layer 4a forming an interface with the film 3, a Ta5ks film is deposited for 1 minute at a substrate temperature of 90°C, and a Tag's film with a thickness of 90 mm is laminated. 6 Next, an insulating layer 4b forming an interface with the second EC layer is deposited to a thickness of 2,910 layers at a substrate temperature of 60°C, resulting in a total film thickness of 3.
,000 insulating layer 4 was formed, and thereafter, the same procedure as in Example 1 was carried out to produce an EC element of the present invention.

When a DC voltage of +1.5V was applied between the first electrode 2 and the second electrode 6 to this EC element with the first electrode 2 as a reference, a concentration change of Δ0D=0.71 was observed at 250 a+gec. , the response speed was improved.

Example 3 In the same manner as in Example 1, a Ta*Os film was deposited for 0.5 minutes at a substrate temperature of 100°C as an insulating layer 4a forming an interface with the IrOx film 3, and a 45-layer Taxes film was laminated. Next, the insulating layer 4b that forms the interface with the second EC layer is deposited to a thickness of 2,955 layers at a substrate temperature of 50° C. to form an insulating layer 4 with a total thickness of 3,000 layers. Example 1
An EC element of the present invention was produced in the same manner as described above.

When a DC voltage of +1.5V was applied between the first electrode 2 and the second electrode 6 to this EC element with the first electrode 2 as a reference, a concentration change of Δ0D=0.78 was observed at 250 m5ec. , the response speed was improved.

(Effect of the invention).

As explained above, when forming the insulating layer, by forming the insulating layer at a high substrate temperature first and then at a lower temperature, it is possible to create an EC element with faster response speed than conventional examples. done.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of an EC element manufactured by the manufacturing method of the present invention, FIG. 2 is a cross-sectional view of an EC element manufactured by a conventional manufacturing method, and FIG. 3 is a cross-sectional view of an EC element manufactured by a conventional manufacturing method. A glass cell is shown, FIG. 4 is a driving device for the glass cell, and FIG. 5 is a sweeping waveform. 1: Substrate 2: First electrode 3: -EC layer (anode side) 4: Insulating layer 5: Second EC layer (cathode side) 6: Second electrode 31.41: Metal iridium film 32.42: Reference electrode (SEC) 33.43: Counter electrode (platinum) 34: Sulfuric acid (H, SO,) aqueous solution 45: Potentiostat 46: Potentio siveber Fig. 2

Claims (3)

[Claims] (1) A first electrode made of a conductive film on a substrate, a first electrochromic layer that is a colored layer on the anode side, an electronic insulating layer that is a good ionic conductor made of a dielectric film, and a second colored layer on the cathode side. In a method for manufacturing an electrochromic device in which an electrochromic layer and a second electrode made of a conductive film are sequentially laminated, the lamination of the insulating layer is performed using a high substrate when forming an interface with the first electrochromic layer. 1. A method for manufacturing an electrochromic device, characterized in that the process is carried out at a low temperature and thereafter at a low substrate temperature. (2) The method for manufacturing an electrochromic device according to claim 1, wherein the first electrochromic layer is an anodized iridium film. (3) The method for manufacturing an electrochromic device according to claim 1, wherein the insulating layer is a tantalum pentoxide film.