JPH0511608B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Field of Industrial Application) The present invention relates to a method for manufacturing an all-solid-state electrochromic device, and more specifically, to an improvement method for improving the characteristics of an all-solid-state electrochromic device. It is related to quality processing.

(Prior Art and Problems to be Solved by the Invention) Electrochromic devices (hereinafter abbreviated as ECD) are characterized by the fact that when a voltage is applied from the outside, a redox reaction is induced in the electrochromic substance in the device. It is an element whose color and light transmittance change reversibly, and is being put into practical use as an element with features not found in LEDs or LCDs.

Various types of ECDs have been developed, but all-solid-state ECDs, in which all layers constituting the element are made of solid materials, are highly reliable and
It has excellent features in terms of cost, versatility, etc.

However, the conventional all-solid-state ECD has a liquid-type ECD.
The drawback was that the change in light transmittance was generally small compared to that of the conventional method. In particular, when used in transmission mode, a large change in light transmittance is often required, which has been a problem.

Structure of the Invention (Means for Solving the Problems) In order to solve the above problems, the present invention provides an oxidized coloring layer, an ion donor layer, and a reducing layer between two electrodes, at least one of which is a transparent electrode. A method was adopted in which an all-solid-state ECD comprising laminated coloring layers was brought into contact with an electrolytic solution and a voltage was applied between both electrodes to cause the element to develop and/or discolor at least once.

(Function) When a voltage is applied between both electrodes while the all-solid-state ECD after lamination is brought into contact with an electrolyte, ions in the electrolyte become more likely to be incorporated into the oxidized coloring layer in the all-solid-state ECD. The ions act on the oxidized coloring layer, causing a chemical change in the oxidized coloring layer.

As a result, the light transmittance change of the all-solid-state ECD becomes large, low-voltage driving becomes possible, and the responsiveness of coloring and erasing improves.

(Example) An example embodying the manufacturing method of the present invention will be described below with reference to FIGS. 1 to 5.

The ECD 1 manufactured in this example is a cellular all-solid-state ECD used in transmission mode, and as shown in FIG. It is formed with an inter-electrode area of 50 x 20 mm.

First, the structure of the ECD 1 after manufacture will be explained according to FIG. The upper surface of the lower transparent electrode 3 is made of _NiO
an oxidized coloring layer ₄ of
Approximately 6000Å thick made of WO ₃ (tungsten oxide)
The reduction color forming layers 6 are sequentially laminated.

Further, an upper transparent electrode 7 made of ITO and having a thickness of about 2000 Å is formed on the upper surface of the reduction color forming layer 6, and lead wires 8 and 9 are connected to the ends of the lower transparent electrode 3 and the upper transparent electrode 7, respectively. There is.

There are several types of all-solid-state ECDs, but
In terms of durability, a type in which an oxidized coloring layer 4, an ion donor layer 5, and a reduced coloring layer 6 are laminated between a pair of electrodes 3 and 7, like the ECD 1 of this embodiment, is advantageous. Compared to a type with a single coloring layer, redox reactions occur complementary to both coloring layers 4 and 6, so
ECD due to corrosion without gas generation due to side reactions
This is because the deterioration of No. 1 is less.

Furthermore, the ECD 1 of this example has been subjected to a modification treatment in which ions are incorporated into the oxidized coloring layer 4 made of _NiO Responsiveness is improved.

Next, the method for manufacturing the ECD 1 will be explained. First, the configurations of the laminating device A and the reforming device B used for manufacturing the ECD 1 will be explained.

The lamination apparatus A is constructed using a vacuum chamber 21 as shown in FIG. 2, and at the center of the inner bottom of the vacuum chamber 21 is a crucible 23 for placing tablets of raw materials for each layer 3, 4, 5, 6, and 7. is installed. Below the crucible 23 is an EB gun 25 connected to an EB (electron beam) power source 24.
High-frequency coils 27 connected to a high-frequency power source 26 are provided above the tablets, so that the tablet vapor evaporated by the EB gun 25 is ionized by the high-frequency coils 27 as required. Further, a holder 28 for supporting the substrate 2 is provided inside and above the vacuum chamber 21.
8 is a heater 29 for heating the substrate 2.
is provided.

As shown in FIG.
1 is placed in the electrolyte tank 32 and ECD1 is
The voltage application device 33 is configured to apply a rectangular wave voltage of 1.5V or any other voltage, and the lead wires 8 and 9 are connected to the output of the voltage application device 33.

Now, the method for manufacturing the ECD 1 using the above-mentioned apparatus will be explained by listing the items in the order of steps.

(1) Cleaning of the substrate 2 First, the substrate 2 is ultrasonically cleaned in a neutral detergent solution, rinsed with distilled water, and air-dried in a clean atmosphere.

(2) Formation of lower transparent electrode 3 The substrate 2 is set in the holder 28 of the laminating apparatus A as shown in FIG.
Heat to 200℃. This is to improve the adhesion of ITO. In addition, the inside of the vacuum chamber 21 is set at 1×10 ^-5 Torr.
After reducing the pressure to 5×10 ^-4 Torr, supply argon gas and oxygen gas.

Next, place the ITO tablet in crucible 23.
It is vaporized by the electron beam emitted from the EB gun 25, and the vapor is transferred to the high frequency coil 27.
The lower transparent electrode 3 was formed by ionizing the electrode and depositing it on the substrate 2.

This method is called ion plating, and because the ion collision energy is extremely high, it is able to form a denser and stronger adhesive layer than the EB method or sputtering method.

(3) Formation of oxidized coloring layer 4 While heating the substrate 2 to 200°C, only argon gas is supplied into the vacuum chamber 21 to reduce the temperature to 1×10 ^-3 Torr.
The atmosphere is as follows.

Then, the _NiOx tablet placed in the crucible 23 was evaporated by an electron beam emitted from the EB gun 25, and the vapor was directly deposited on the lower transparent electrode 3, thereby forming the oxidized coloring layer 4.

This is a method called the EB method (electron beam method), and since the collision energy is lower than that of the ion plating method, it is possible to form an adhesion layer with appropriate porosity. The porosity of the oxidized coloring layer 4 increases the coloring density.

(4) Formation of ion donor layer 5 The substrate 2 is heated to about 300°C, and argon gas and oxygen gas are supplied into the vacuum chamber 21 to give a temperature of 5×10 ^-4 Torr.
The atmosphere is as follows.

Then, Ta ₂ O ₅ placed in the crucible 23 was evaporated and ionized by the ion plating method described above to form an ion donor layer 5 on the upper surface of the oxidized coloring layer 4 .

(5) Formation of reduction coloring layer 6 The substrate 2 is heated to about 200°C, and argon gas or nitrogen gas is supplied into the vacuum chamber 21 to form a 1×10 ^-3
Creates a Torr atmosphere.

Then, the WO ₃ placed in the crucible 23 was evaporated by the EB method described above to form a reduction coloring layer 6 on the upper surface of the ion donor layer 5.

(6) Formation of upper transparent electrode 7 The upper transparent electrode 7 was formed on the upper surface of the reduction coloring layer 6 by the same method as the lower transparent electrode 3.
This completes the lamination process of ECD1.

(7) Attaching the lead wires 8 and 9 Take out the ECD 1 from the vacuum chamber 21 of the laminating device A,
Lead wires 8 and 9 were bonded to both electrodes 3 and 7.

(8) Modification process Next, as shown in FIG. was connected to the other output terminal 35.

In addition, a 1.7N (regular) LiCl aqueous solution is put into the electrolytic solution layer 32 of the reforming treatment device B as the electrolytic solution 31,
The ECD 1 was dipped in the electrolytic solution 31.

Then, as shown in FIG. 3, the voltage application device 33 outputs a
Apply a square wave voltage of 1.5V and a period of 10 seconds, and ECD1
was colored and discolored.

That is, when the ground voltage of the voltage application device 33 connected to the upper transparent electrode 7 is set to 0V and 1.5V is applied to the lower transparent electrode 3, the oxidized coloring layer 4, which was previously light brown, becomes dark brown. At the same time, the reduction color forming layer 6, which had been transparent until then, developed a blue color, so that the entire color developed into a dark gray color.

Similarly, when -1.5V is applied to the lower transparent electrode 3, the oxidation coloring layer 4 also reduces the reduction coloring layer 6.
It also faded back to its original color. It is believed that these coloring and decoloring phenomena occur because an oxidation-reduction reaction occurs between the oxidized coloring layer 4 and the reduced coloring layer 6.

Here, since the above voltage application is performed in the electrolytic solution 31, ions in the electrolytic solution 31 are transferred to the oxidized color forming layer 4.
(NiO _x ), and a chemical change occurs in the oxidized coloring layer 4. One manifestation of this is that the oxidized coloring layer 4 had a pale brown color when it was laminated, but after the coloring and decoloring, it changed to a clear transparent color (both colors when no voltage is applied).

As above, apply a rectangular wave voltage of 300 to ECD1.
After repeating color development and decolorization 30 times by applying the voltage for 2 seconds, the ECD 1 was taken out from the electrolytic solution 31, rinsed with distilled water, and dried. Above
The modification process of ECD1 is completed.

(9) Light Transmittance Test A light transmittance test was conducted in the atmosphere for each of the untreated ECD before the modification treatment and the treated ECD 1 after the treatment to confirm the effect of the modification treatment.

In this test, the upper transparent electrode 7 of each ECD is 0V, and the lower transparent electrode 3 is 1V → 1.2V → 1.4V → 1.6V →
A DC voltage of 1.7V (1.7V is only for untreated ECD) is applied stepwise until the light transmittance is almost saturated, and the light transmittance when the color is erased by applying -1V is used as the reference. The ΔOD (optical density, change in optical density) was measured for each wavelength of light.

ΔOD is a logarithmic representation of the change in light transmittance, and ΔOD of 0 means that the light transmittance does not change compared to the time of decolorization. Also, ΔOD of 1 means that the light transmittance has changed to 10%,
ΔOD of 2 means that the light transmittance has changed to 1%.

Figure 4 shows the measurement results of untreated ECD, and Figure 5
The figure shows the measurement results of processed ECD1.

Now, if we compare Figures 4 and 5, we can see that the unprocessed
It can be seen that, compared to the ECD, in the treated ECD 1, ΔOD increases at all wavelengths when the same voltage (for example, 1.4 V) is applied.

Also, in order to make ΔOD on the long wavelength side 2,
While the untreated ECD requires the application of 1.7V, the treated ECD1 requires the application of 1.6V. That is, it can be seen that a desired change in light transmittance can be obtained with a lower voltage in the treated ECD 1 than in the untreated ECD, and therefore low voltage driving is possible.

These effects in the treated ECD 1 are due to the fact that ions in the electrolytic solution 31 are incorporated into the oxidized coloring layer 4 (NiO _x ) through the modification treatment, and a chemical change occurs in the oxidized coloring layer 4. This is thought to be due to this.

(10) Responsiveness test Next, a decoloring responsiveness test was conducted in the air for each of the untreated ECD and the treated ECD1 to confirm the effect of the modification treatment.

This test requires 1.5V to the lower transparent electrode 3 of each ECD.
was applied to develop color, and then -1.5V was applied to the lower transparent electrode 3, and the decoloring response time (time shown in FIG. 3) was measured.

As a result, the decolorization response time is 0.90 for untreated ECD.
The decolorization response time was 0.60 seconds for the treated ECD1, so it can be seen that the decolorization response time was shortened by 33% by the modification treatment. This effect is also considered to be due to the fact that ions in the electrolytic solution 31 are incorporated into the oxidized coloring layer 4 and act on it due to the modification treatment, causing a chemical change in the oxidized coloring layer 4.

In addition, it was confirmed that not only the decoloring response but also the coloring response was similarly improved by the modification treatment.

As mentioned above, the ECD manufactured by the method of this example
1 has a large change in light transmittance due to the modification treatment and improved responsiveness for coloring and decoloring, so it is suitable for use in transmission mode where a large change in transmittance is required or for use where high responsiveness is required. Not only is it suitable for use in applications, but it also has excellent versatility because it can be driven at low voltage.

Furthermore, since the modification treatment can be performed using simple equipment and processes, excellent ECD can be easily and inexpensively produced as described above.

It should be noted that the present invention is not limited to the configuration of the above-mentioned embodiments, and may be modified and embodied as desired without departing from the spirit of the invention, for example, as described below.

(1) As the electrolyte 31, in addition to LiCl, H ₂ SO ₄ ,
HCl, NaCl, KCl, MgCl ₂ , CaCl ₂ , NaBr,
NaNO ₃ , Na ₂ SO ₄ , NaClO ₄ , LiClO ₄ ,
KNO ₃ , Mg(NO ₃ ) _2, etc. can be used. In short, any electrolytic solution can be selected as long as it can take in many ions and increase the current.

Among the electrolytes mentioned above, those with particularly high reforming effects were H ₂ SO ₄ , HCl, NaCl, KNO ₃ ,
It was _NaClO4 .

However, electrolytes with a pH higher than 7, such as NaF,
ECD of the above example to NaOH, Na ₂ CO ₃ , K ₂ CO ₃
When dipping No. 1, peeling occurred in the upper transparent electrode 7, so care must be taken. this is,
This is considered to be because the reduced coloring layer 6 (WO ₃ ) was dissolved by the alkali. However, by changing the constituent materials of the reduction coloring layer 6 and the like, it is possible to use an electrolytic solution with a pH exceeding 7.

In addition, although HCl has a large modifying effect, when the concentration was increased, elution of transparent electrodes 3 and 7 was observed.
It is preferable to avoid using high concentrations.

(2) The concentration of the electrolytic solution 31 is not limited to the above-mentioned 1.7N, but can be changed significantly depending on the type of electrolytic solution.

FIG. 6 shows the results of investigating the influence of the electrolyte concentration on the decoloring response time and its durability using NaCl as the electrolyte.

Regardless of the concentration from 0.0017N to 1.7N, the decolorization response time immediately after the modification treatment is shortened.

However, those treated with an electrolytic solution having a concentration of 0.17N or more are particularly preferable because there is little delay (deterioration) in the decoloring response time even in the durability test after treatment.

(3) The applied voltage and method in the modification treatment are not limited to the methods of the above embodiments, and can be arbitrarily changed.

The appropriate voltage to be applied is 1 to 2 V, taking processing efficiency and ECD corrosion into consideration. In addition to a rectangular wave, a sine wave, a triangular wave, a pulse wave, etc. can be used as the applied waveform, and there is no particular limitation on the period.

The number of voltage applications (cycle number) is also not limited to 30 times, and may be arbitrarily determined in the range of about 1 to 1000 times depending on the type and concentration of the electrolytic solution, the applied voltage, etc.

Practically speaking, it is considered preferable in terms of efficiency to apply a rectangular wave voltage of ±1.3V with a period of about 1 second.

In addition, the applied voltage does not necessarily have to be an alternating voltage, but simply applying direct current for a certain period of time,
Even if ECD is caused to produce only either color development or color decolorization, the modification effect is observed.

(4) In addition to soda glass, organic glass such as polymethyl methacrylate can also be used as the substrate 2. However, when organic glass is used, all-solid-state molding is performed on the same glass at a temperature below its deformation temperature.
Must be allowed to form an ECD.

Further, the substrate 2 may be placed on either side of the electrodes 3 and 7.

(5) The present invention is not limited to all-solid-state ECDs used in transparent mode, but can also be implemented in ECDs used in reflective mode. In this case, at least one of the electrodes 3 and 7 may be a transparent electrode, and the other electrode may be a reflective layer or a colored layer. Further, the substrate 2 in the case of reflection mode may be opaque.

(6) As the constituent material of the transparent electrodes 3 and 7, other than ITO, thin films such as TiO ₂ , SnO ₂ , Au, Ag, Pt, etc. can also be used. That is, any material that is electrically conductive and substantially transparent to light may be used.

(7) In addition to NiO _x , the constituent substances of the oxidized coloring layer 4 include Ni(OH) _x , Cr ₂ O ₃ , Ir(OH) _x , IrO _x ,
_RhOx , Rh(OH) _x , Ru(OH) _x , etc. can be used.

Further, even when forming the same oxidized coloring layer 4 of NiO _x , it is also possible to perform the EB method using a Ni tablet and oxidize it during evaporation to form NiO _x .

(8) The constituent materials of the ion donor layer 5 include those mentioned above.
In addition to Ta ₂ O ₅ , LiF, SiO ₂ , ZrO ₂ , Cr ₂ O ₃ ,
MgF ₂ , CaF ₂ , Ai ₂ O ₃ , Y ₂ O ₃ , Na-β-alumina, Li ₃ N (Li ⁺ ), etc. can be used.
That is, any material can be selected as long as it allows ions to pass through but not electrons.

(9) In addition to WO ₃ , MoO ₃ , V ₂ O ₅ , Nb ₂ O ₅ and the like can be used as constituent substances of the reduction coloring layer 6. The lamination position of the reduction coloring layer 6 in the above embodiment may be replaced with the lamination position of the oxidation coloring layer 4.

(10) Each of the layers 3, 4, 5, 6, and 7 can also be formed by an ion plating method, an EB method, a sputtering method, or a vacuum evaporation method other than the methods employed in the embodiments.

Effects of the Invention As detailed above, according to the manufacturing method of the present invention, it is possible to easily and inexpensively produce an electrochromic element that has a large change in light transmittance, can be driven at low voltage, and has good coloring and decoloring responsiveness. It has the excellent effect of being able to be manufactured in a number of ways.

[Brief explanation of drawings]

1 to 5 show an embodiment embodying the present invention, FIG. 1 is a cross-sectional view showing the modification process of an all-solid-state ECD, and FIG. 2 is a cross-sectional view showing the lamination process of the ECD. Figure 3 is a diagram showing the voltage applied to the ECD and the change in light transmittance of the ECD over time, and Figure 4 is an untreated diagram.
A diagram showing the relationship between applied voltage, wavelength, and optical density change in ECD, Figure 5 is a diagram showing the relationship between applied voltage, wavelength, and optical density change in processed ECD, and Figure 6 is a diagram showing the relationship between applied voltage, wavelength, and optical density change in ECD. FIG. 2 is a diagram showing the relationship between the concentration of an electrolytic solution, the cycle of color development and decolorization, and the decolorization response time. 1... Electrochromic device (ECD), 2
... Substrate, 3 ... Lower transparent electrode, 4 ... Oxidation coloring layer, 5 ... Ion donor layer, 6 ... Reduction coloring layer,
7... Upper transparent electrode, 31... Electrolyte, 33...
Voltage application device.

Claims (1)

[Claims] 1. An all-solid-state electrochromic device in which an oxidation coloring layer 4, an ion donor layer 5, and a reduction coloring layer 6 are laminated between two electrodes 3 and 7, at least one of which is a transparent electrode. In the manufacturing method of the Tsuku element,
All-solid-state electrochromic device 1 after lamination
An all-solid-state electrochromic device characterized in that the device 1 is colored and/or decolored at least once by applying a voltage between the electrodes 3 and 7 while bringing the device 1 into contact with an electrolytic solution 31. manufacturing method. 2. The method for manufacturing an all-solid-state electrochromic device according to claim 1, wherein the electrolytic solution 31 is an electrolytic solution having a pH of 7 or less. 3 The voltage applied between the electrodes 3 and 7 is 1 to 2 V.
A method for manufacturing an all-solid-state electrochromic device according to claim 1.