JP2009145458A - Electrochromic device and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrochromic device having a highly transparent porous electrode having a porous structure and excellent adhesiveness, and to provide its manufacturing method. <P>SOLUTION: In the electrochromic device wherein a counter electrode structure 12 having a first transparent electrode 72 and a first porous electrode 8 carrying an organic radical compound 13 which are formed on a first supporting substrate 6 and a display electrode structure 11 having a second transparent electrode 2 and a second porous electrode 4 carrying an electrochromic dyestuff 3 which are formed on a second supporting substrate 1 are disposed sandwiching an electrolyte layer 5 so that both transparent electrodes are opposed to each other, the first porous electrode is composed of a cylindrical body having pores each nearly vertical to the surface of the first supporting substrate and having ≤20 nm in length. The first porous electrode is manufactured by a magnetron sputtering method at low temperature in a vacuum vessel in which an inert gas and an oxygen gas in its rate of 10 to 90% expressed in terms of patial pressure exist and which has 0.5 to 6.0 Pa total pressure. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electrochromic device and a method for manufacturing the same, and in particular, it has excellent response speed, color development efficiency, display color purity, can form a clear and sharp image, has excellent repeated durability, and is made thin and flexible. The present invention also relates to an electrochromic device that can cope with the above and a manufacturing method thereof.

  In recent years, there has been a growing demand for display pigment materials and display elements using the same that are bright and excellent in color purity, have low power consumption, and can be easily applied to full-color display. Conventionally, CRT (Cathode Ray Tube), PDP (Plasma Display Panel), ELD (Electroluminescence Display) VFD (Vacuum Fluorescent Display), FED (Field Emission Display), LED (Light Emitting Diode) and other light emitting elements, DMD (Digital Many technologies have been proposed for non-light emitting elements such as a micromirror display (LCD), a liquid crystal display (LCD), an electrochromic display (ECD), and an electrophoresis display (EPD).

  However, a display device using various light-emitting elements known in the art is used in such a form that the user directly looks at the light emission, and thus has a problem of causing visual fatigue when viewed for a long time.

  In particular, LCD is a technology with increasing demand among non-light emitting devices, and it is used for various display applications such as large and small. However, LCD has a narrow viewing angle and is improved from the viewpoint of ease of viewing. There are issues to be addressed. In addition, mobile devices such as mobile phones that use LCDs are often used outdoors, and there is a problem in that visibility deteriorates because display light is offset under sunlight.

  With respect to reflective display elements among non-light emitting elements, various techniques have been proposed in the past due to an increase in demand for electronic paper. For example, a reflective LCD or an electrophoretic display device can be used.

  As the reflective LCD, a GH type liquid crystal system using a dichroic dye, a cholesteric liquid crystal, and the like are known. These methods have the advantage of power saving because they do not use a backlight as compared to conventional transmissive LCDs, but they have a viewing angle dependency and low light reflection efficiency, so There is a problem that the screen becomes dark.

  On the other hand, an electrophoretic display device uses a phenomenon in which charged particles dispersed in a solvent move by an electric field, and has the advantages of low power consumption and no viewing angle dependency. However, when performing full color, it is necessary to apply a juxtaposed mixing method using a color filter, so that there is a problem that the reflectance is lowered and the screen is inevitably darkened.

  In recent years, an electrochromic (hereinafter abbreviated as EC) element has been proposed for a light control mirror, a timepiece, or the like of an automobile. This EC element does not require a polarizing plate, has no viewing angle dependency, has a color development type, has excellent visibility, has a simple structure and can be easily enlarged, and displays various colors depending on the choice of materials. Has the advantage of being possible.

  As an example of a display device using a specific EC element, there is a display device having a structure in which a semiconductor nanoporous layer is provided on at least one of a pair of transparent electrodes and an EC dye is supported on the semiconductor nanoporous layer. It has been proposed (see, for example, Patent Documents 1 and 2 and Non-Patent Documents 1 and 2 described later). These display devices can be held in a static state just by forming an open circuit to block the movement of electrons between the electrodes and maintaining the oxidation-reduction state, so no power is required to maintain the display image and consumption It is excellent in that the power is extremely low.

  An EC display having a structure in which structural units each supporting EC dyes of yellow, cyan, and magenta are stacked and capable of performing full color display is well known (for example, Patent Documents 3, 4, and 5 described later). See).

  Patent Documents 1 and 2 and Non-Patent Document 1 to be described later describe a configuration in which a metal oxide semiconductor porous electrode supporting a phenothiazine derivative is provided, and Non-Patent Document 2 to be described later as a counter electrode. A configuration in which an antimony-doped tin oxide (ATO) porous electrode is provided on a transparent electrode is described.

  Patent Documents 1 and 2 entitled “Electrochromic Device” include the following description.

  The method for forming the semiconductor nanoporous layer is not particularly limited and can be appropriately selected depending on the type of semiconductor. For example, metal anodization method, cathode deposition method, screen printing method, sol-gel method, thermal oxidation Method, vacuum vapor deposition method, dc and rf sputtering method, chemical vapor deposition method, metalorganic chemical vapor deposition method, molecular beam deposition method, laser ablation method, etc. Layers can also be made.

Non-Patent Document 3 to be described later describes the influence of oxygen partial pressure on the properties of an indium tin oxide (ITO) film formed on a glass substrate by RF reactive magnetron sputtering. Document 4 describes the preparation of antimony-doped tin oxide (SnO ₂ : Sb) by RF magnetron sputtering on a glass substrate.

JP 2003-248242 A (paragraph 0008, paragraph 0025, FIGS. 1 and 2) JP 2003-270670 A (paragraph 0008, paragraph 0031, FIGS. 1 to 4) JP 2007-10975 A (paragraph 0028, paragraph 0046) JP 2007-41259 (paragraphs 0011 to 0012, paragraph 0148, FIGS. 1 to 4) JP 2007-121714 A (paragraphs 0071 to 0088) H. Pettersson et al, “Direct-driven electrochromic displays based on nanocrystalline electrodes”, Display, 25 (2004) 223-230 (Abstract) D. Cummins et al, “Ultrafast Electrochromic Windows Based on Redox-Chromophore Modified Nanostructured Semiconducting and Conducting Films”, J. Phys. Chem. B 2000, 104, 11459 11459 (Abstract) L. J. Meng, M. P. dos Snatos, “Study of the effect of the oxygen partial pressure on the properties of rf reactive magnetron sputtered tin-doped indium oxide films”, Applied surface Science, 120 (1997) 243-249 (Abstract, Conclusions) Y. Wang et al, “Structural and photoluminescence characters of SnO2: Sb films deposited by RF magnetron sputtering”, Journal of Luminescence 114 (2005) 71-76 (Abstract, Conclusions) E. P. Barrett et al, “The Determination of Pore Volume and Area Distributions in Porous Substance. I. Computations from Nitrogen Isotherms”, J. Am. Chem. Soc., 73 (1951) 373 -380 (Summary)

  Antimony-doped tin oxide (ATO) constituting the counter electrode of the display device described in Non-Patent Document 2 is a material that is colored dark gray, and is not a suitable material as an electrode material for performing color display. There wasn't.

  Moreover, the phenothiazine derivative carried on the metal oxide semiconductor porous electrode constituting the counter electrode of the display device described in Patent Documents 1 and 2 and Non-Patent Document 1 has a property of developing a red color by an oxidation reaction. For this reason, the display electrode side has the disadvantage of hindering the desired color display by the EC dye. In particular, three color layers of cyan (C), magenta (M), and yellow (Y) were laminated for the purpose of obtaining a transparent display device or for clear full-color image display. When constructing a device having a configuration, the counter electrode is made of a colorless and transparent material, and the material carried on the counter electrode may not cause a hue change due to an oxidation / reduction reaction. Ideal.

  In such an electrochromic display device, it is required to positively charge (oxidize) the counter electrode, that is, the counter electrode needs a storage capacity, and in order to realize a counter electrode having a storage capacity, (1) A method of using an ATO (antimony-doped tin oxide) electrode having a storage capacity as a porous electrode, (2) A method of supporting (adsorbing) an oxidizable (capable of storing) organic substance on a porous electrode having no storage capacity However, in the method (1), as described above, the ATO is a material that is colored dark gray and is always colored, and has the disadvantage of degrading the display quality. In the method (2), the voltage is reduced. There is a disadvantage that the color produced by the oxidation of the organic substance when applied is applied and the display quality is deteriorated.

  In order to display a full-color image, when a device having a structure in which three color developing layers of cyan (C), magenta (M), and yellow (Y) are stacked is to be constructed, the support substrate is transparent. A suitable material is preferred. In order to reduce the parallax of each pixel, a thin material having sufficient mechanical strength is suitable for the support substrate.

  Furthermore, in order to increase the degree of freedom of shape in order to improve the convenience as a display device, it is desirable that it is a flexible form. In this case, a plastic material is suitable for the support substrate. Therefore, it is necessary to ensure strong adhesion between the porous electrode and the support substrate so that the change in shape can be followed.

  However, in the prior art, since the porous electrode is formed under a high temperature condition, there is a problem that it cannot be applied to the case where the flexible display device described above is manufactured due to the heat resistance of the plastic material. It was.

  As an electrode of a display device for performing color display, it has been desired to form an electrode film (layer) having no dark color and excellent in transparency on a plastic substrate under a low temperature condition.

  Note that Patent Document 1 and Patent Document 2 describe that a porous electrode can be formed by a sputtering method, but do not describe details of film forming conditions by the sputtering method. Further, there is no description about forming a transparent porous electrode having a large transmittance by a magnetron sputtering method.

  Although the formation of flat ATO films and ITO films has been studied by sputtering, no report has been made that a porous film having mesoscale pores has been created by sputtering. This is presumably because the ATO film and ITO film have poor electrical characteristics unless they have a dense structure.

  Non-Patent Documents 3 and 4 describe that an ATO film and an ITO film are formed on a glass substrate by magnetron sputtering, but the mesoscale pore structure is not described.

  Hereinafter, in this specification, the “porous electrode” means an electrode having a large specific surface area and a pore structure capable of supporting any molecule, and IUPAC (International Union of Pure and Applied Chemistry) of a porous body according to pore diameter. ), Pores with 2 nm <diameter <50 nm are referred to as mesopores, and “mesoscale pores” mean pores with 2 nm <diameter <50 nm.

  The present invention has been made in order to solve the above-described problems, and the object thereof is to be formed under relatively low temperature conditions, and has a pore structure and excellent adhesion to a support substrate. Another object of the present invention is to provide a preliminary method for manufacturing an electrochromic device that has a highly transparent porous electrode, is suitable for color display, has high color purity, and is excellent in repeated durability of color development and decoloration.

  That is, the present invention provides a first transparent electrode (transparent electrodes 7, 7a, 7b in the embodiment described later) on the first support substrate (support substrates 6, 6a, 6b, 6c in the embodiment described later). 7c), and a counter electrode structure (described later) in which a first porous electrode (porous electrodes 8, 8a, 8b, 8c in embodiments described later) is formed on the first transparent electrode. Counter electrode structures 12, 12 a, 12 b, 12 c) in the form and a second transparent electrode (support described later) on the second support substrate (support substrates 1, 1 a, 1 b, 1 c in the embodiment described later) Transparent electrodes 2, 2 a, 2 b, 2 c) are formed, and a second porous electrode (porous electrodes 4, 4 a, 4 b, 4 c in embodiments described later) is formed on this second transparent electrode. , Oxidation reaction or reduction on the second porous electrode Display electrode structures (display electrode structures 11, 11a, 11b in the embodiments described later) on which electrochromic dyes (organic EC dyes 3, 3a, 3b, 3c in the embodiments described later) are supported 11c) and an electrolyte layer sandwiched between the first and second transparent electrodes (electrolyte layers 5, 5a, 5b, 5c in the embodiments described later), and the first porous The electrode relates to an electrochromic device in which the electrode is substantially perpendicular to the surface of the first support substrate and is made of a columnar body having mesoscale pores.

  The present invention also provides a counter electrode structure in which a first transparent electrode is formed on a first support substrate, and a first porous electrode is formed on the first transparent electrode, and a second support substrate. A second transparent electrode is formed thereon, a second porous electrode is formed on the second transparent electrode, and an electrochromic dye that develops color by an oxidation reaction or a reduction reaction is supported on the second porous electrode. The display electrode structure is a method for manufacturing an electrochromic device in which an electrolyte layer is sandwiched so that the first and second transparent electrodes are opposed to each other, on the first transparent electrode The first porous electrode comprising a step of forming the first porous electrode by magnetron sputtering, and comprising a columnar body having mesoscale pores substantially perpendicular to the surface of the first support substrate. Formed, elect Those relating to the manufacturing method of chromic device.

  According to the present invention, the first porous electrode is formed of a columnar body that is substantially perpendicular to the surface of the first support substrate and has mesoscale pores. Therefore, in addition to the gap between the columnar bodies, The transparent first porous electrode having a good pore structure as an electrode for an EC element and having excellent adhesion to the first support substrate needs to be subjected to a high-temperature baking process of about 500 degrees. However, it can be formed under relatively low temperature conditions, and a plastic substrate or a thin layer substrate can be used as the first support substrate. It is possible to provide an electrochromic device that has a response speed and color development efficiency that are practically sufficient for color display, is clear, has high color purity, and is excellent in durability of repeated color development and decoloration. The mesoscale pores mean pores having 2 nm <diameter <50 nm.

  In addition, according to the present invention, the method includes a step of forming the first porous electrode on the first transparent electrode by magnetron sputtering, and is substantially perpendicular to the surface of the first support substrate. Since the first porous electrode is formed of a columnar body having a plurality of pores, the first porous electrode has an excellent pore structure as an electrode for an EC element in addition to the gap between the columnar bodies. The transparent first porous electrode having excellent adhesion to the support substrate can be formed under relatively low temperature conditions, and a plastic substrate or a thin layer substrate can be used as the first support substrate. It is possible to increase the degree of freedom of configuration, such as flexibility, has a response speed and coloration efficiency sufficient for practical use for color display, is clear and has high color purity, and excellent durability for repeated color development and decoloration. Made electrochromic devices The method can be provided.

  In the electrochromic device of the present invention, the first porous electrode is preferably composed of a columnar body having pores of 20 nm or less. According to this configuration, since the columnar body has pores of 20 nm or less, in addition to the gaps between the columnar bodies, an organic radical compound having a nitrooxy radical group (an organic radical compound in an embodiment described later) 13, 13a, 13b, and 13c) can be adsorbed and supported in the single molecule state as much as possible, the electric capacity in the counter electrode structure can be increased, and the color development efficiency can be improved.

  The first porous electrode is made of a semiconductor, and the semiconductor is made of a metal oxide or a composite of metal oxide, and the metal is any one of indium, tin, zinc, and aluminum. It is good to do. According to this configuration, the first porous electrode can be formed transparently, and a configuration for performing color display can be realized. The metal oxide may contain a dopant.

  Further, the first porous electrode uses an RF (high frequency) power source or a DC (direct current) power source, and oxygen gas is present in a ratio of 10% to 90% in terms of partial pressure in addition to the inert gas. And it is good to set it as the structure formed by magnetron sputtering in the vacuum chamber whose total pressure is 0.5 Pa or more and 6.0 Pa or less. According to this configuration, it is possible to form a transparent porous electrode having a pore structure and excellent adhesion to the first support substrate.

  The first porous electrode may be an antimony-doped tin oxide porous electrode. According to this configuration, since a transparent porous electrode can be formed, it is possible to provide an electrochromic device that is clear and can have high color purity.

  The antimony-doped tin oxide porous electrode is preferably supported by an organic radical compound having a nitrooxy radical group. According to this configuration, the electric capacity of the counter electrode structure can be increased, and the coloring efficiency can be improved.

  The antimony-doped tin oxide porous electrode may be formed by magnetron sputtering using a target material mainly composed of tin or tin oxide. According to this configuration, since a transparent porous electrode can be formed, it is possible to realize an electrochromic device that is clear and can have high color purity. More specifically, the target material may be mainly composed of an antimony-tin sintered body or alloy, or antimony-doped tin oxide.

  The first support substrate may be a plastic substrate, and the surface temperature of the plastic substrate when the antimony-doped tin oxide porous electrode is formed may be 300 degrees Celsius or less. According to this configuration, it is possible to provide an electrochromic device that can increase the degree of freedom of configuration, such as flexibility.

  The counter electrode structure may have a transmittance of 85% or more in a wavelength region of 450 nm to 800 nm. According to this configuration, it is possible to provide an electrochromic device that is clear and can have high color purity. Here, the transmittance is measured for the counter electrode structure in which the first transparent electrode and the first porous electrode are formed on the first support substrate, It is the transmittance | permeability measured in the state by which the organic radical compound which has a nitrooxy radical group is not carry | supported by the 1st porous electrode.

  In the method for manufacturing an electrochromic device of the present invention, the first porous electrode composed of a columnar body having pores of 20 nm or less is preferably formed. According to this configuration, since the columnar body has pores of 20 nm or less, a large number of organic radical compounds having a nitrooxy radical group are adsorbed to the pores in addition to the gaps between the columnar bodies in a single molecular state as much as possible. An electrochromic device that can increase the electric capacity of the counter electrode structure and improve the color development efficiency can be manufactured.

  The first porous electrode is made of a semiconductor, and the semiconductor is made of a metal oxide or a composite of metal oxide, and the metal is any one of indium, tin, zinc, and aluminum. It is good to do. According to this configuration, the first porous electrode can be formed transparently, and an electrochromic device capable of performing a color display can be manufactured. The metal oxide may contain a dopant.

  Further, the first porous electrode uses an RF (high frequency) power source or a DC (direct current) power source, and oxygen gas is present in a ratio of 10% to 90% in terms of partial pressure in addition to the inert gas. And it is good to set it as the structure formed by magnetron sputtering in the vacuum chamber whose total pressure is 0.5 Pa or more and 6.0 Pa or less. According to this configuration, it is possible to manufacture an electrochromic device in which a porous electrode having a pore structure and excellent adhesion to the first support substrate is formed.

  Further, it is preferable that power is directly supplied to the first transparent electrode and a voltage is applied between the first transparent electrode and the target. According to this configuration, since power is directly supplied to the first transparent electrode and a voltage is applied between the first transparent electrode and the target, plasma is efficiently generated, and sputtering from the target is promoted. The deposition rate of the particles sputtered from the target onto the first transparent electrode can be increased.

  The first porous electrode may be an antimony-doped tin oxide porous electrode. According to this configuration, since a transparent porous electrode can be formed, it is possible to manufacture an electrochromic device that is clear and can have high color purity.

  Moreover, it is good to set it as the structure which has the process of carry | supporting the organic radical compound which has a nitrooxy radical group in the said antimony dope tin oxide porous electrode. According to this configuration, it is possible to manufacture an electrochromic device that can increase the electric capacity of the counter electrode structure and improve the coloring efficiency.

  The antimony-doped tin oxide porous electrode may be formed by magnetron sputtering using a target material mainly composed of tin or tin oxide. According to this configuration, since a transparent porous electrode can be formed, it is possible to manufacture an electrochromic device that is clear and can have high color purity. More specifically, the target material may be mainly composed of an antimony-tin sintered body or alloy, or antimony-doped tin oxide.

  The first support substrate may be a plastic substrate, and the surface temperature of the plastic substrate when the antimony-doped tin oxide porous electrode is formed may be 300 degrees Celsius or less. According to this configuration, it is possible to manufacture an electrochromic device that can increase the degree of freedom of configuration, such as flexibility.

  The counter electrode structure may have a transmittance of 85% or more in a wavelength region of 450 nm to 800 nm. According to this configuration, it is possible to manufacture an electrochromic device that is clear and can have high color purity. Here, the transmittance is measured for the counter electrode structure in which the first transparent electrode and the first porous electrode are formed on the first support substrate, It is the transmittance | permeability measured in the state by which the organic radical compound which has a nitrooxy radical group is not carry | supported by the 1st porous electrode.

  Hereinafter, the electrochromic device of the present invention will be specifically described with reference to the drawings. However, the present invention is not limited to the following examples, and conventionally known configurations can be appropriately added, and this does not depart from the gist of the present invention.

Embodiments Conventionally, a high temperature heating step of about 500 ° C. was required in the production of a porous electrode for an organic electrochromic (EC) device, but it was formed on a polymer substrate for the purpose of practical use. It is necessary to form a transparent porous electrode on the dense transparent electrode formed by a non-heating step without heating the polymer substrate to a high temperature. In the present invention, the antimony-doped tin oxide porous electrode is formed on the transparent electrode by a non-heating step by magnetron sputtering. Thereby, the transparent porous electrode for organic EC apparatuses very suitable for full color display can be provided. The transparent porous electrode of the present invention is composed of an assembly of columnar bodies having a columnar structure and grown in a columnar shape, the columnar body has mesoscale pores, and the transparent porous electrode grows in a columnar shape on the transparent electrode. And has a columnar structure made up of a collection of columnar bodies that are substantially perpendicular to the surface of the support substrate and have mesoscale pores.

  The electrochromic device according to the present invention is excellent in adhesion with a transparent electrode to which a voltage is directly applied, has a high light transmittance, can be formed under relatively low temperature conditions, and is an organic electrochromic compound and / or organic It has a porous electrode with pores that fully support radical compounds, has a sufficient response speed and color development efficiency for color display, has excellent display color purity, and enables clear and sharp image formation. It is excellent in repeated durability and can be made thin and flexible.

  The electrochromic device according to the present embodiment includes a first support substrate, a first transparent electrode formed on the first support substrate, and a first porous electrode formed on the first transparent electrode. Display electrode structure including a porous electrode, a second support substrate, and a second porous electrode (ATO (antimony trioxide) formed on the second transparent electrode formed on the second support substrate A counter electrode structure including a tin oxide composite oxide) porous electrode), a display electrode structure, and an electrolyte layer sandwiched between the counter electrode structures, and a first transparent electrode and a second transparent electrode, Are arranged so as to face each other, and an organic electrochromic compound that develops color by an oxidation reaction or a reduction reaction is supported on the second porous electrode, and the voltage applied between the first transparent electrode and the second transparent electrode is controlled. By organic electrochromic Electrochromic device that performs reversible color development and decolorization with a chemical compound, and is inactive using a target material based on antimony-tin or antimony trioxide-tin oxide composite oxide, RF power supply or DC power supply In a vacuum chamber (film formation chamber) in which at least oxygen gas is present in a ratio of 10% or more and 90% or less in terms of partial pressure in addition to gas, and the total pressure is 0.5 Pa or more and 6.0 Pa or less The ATO porous electrode is formed by magnetron sputtering.

  The ATO porous electrode is transparent, and its transmittance is 85% or more in the region of 450 nm or more and 800 nm or less, and 90% or more in the region of 500 nm or more and 800 nm or less. The first and second support substrates are plastic substrates, and the surface temperature of the plastic substrate when the porous electrode is formed (the temperature shown below is in degrees Celsius) is 300 degrees or less.

  The manufacturing method of the electrochromic device according to the present embodiment uses a target material mainly composed of antimony-tin or antimony trioxide-tin oxide composite oxide, an RF power source or a DC power source, and at least in addition to an inert gas. In a vacuum chamber (deposition chamber) in which oxygen gas is present at a rate of 10% or more and 90% or less in terms of partial pressure, and the total pressure is 0.5 Pa or more and 6.0 Pa or less, by magnetron sputtering, A step of forming an ATO (antimony trioxide-tin oxide composite oxide) porous electrode.

  In the above production method, a tin oxide porous electrode having a transmittance of 85% or more can be formed in a region of 450 nm or more and 800 nm or less, and 90% or more in a region of 500 nm or more and 800 nm or less. An ATO porous electrode having a transmittance of can be formed. Furthermore, a plastic substrate can be used as the first and second support substrates, and the surface temperature of the plastic substrate when forming the ATO porous electrode can be set to 300 ° C. or less.

  In the above manufacturing method, when the oxygen gas is present at a ratio of 10% or more and 50% or less in terms of partial pressure, and the total pressure is 2 Pa, the deposition rate of the ATO porous electrode is increased. Further, when the oxygen gas is present at a ratio of 50% in terms of partial pressure and the total pressure is 2.0 Pa or less, the film formation rate of the ATO porous electrode is increased.

Further, when oxygen gas is present at a ratio of 50% in terms of partial pressure and the total pressure is 0.5 Pa or more and 6.0 Pa or less, the BET specific surface area is about 10 to about 40 (cm ² g ^{− 1} ) When the film thickness is 3 μm, an ATO porous electrode having an average transmittance of about 85% or more at 400 nm to 800 nm can be formed, and oxygen gas is in a ratio of 50% in terms of partial pressure. 400 nm when the BET specific surface area is about 20 to about 40 (cm ² g ⁻¹ ) and the film thickness is 3 μm when the total pressure is 0.5 Pa or more and 2.0 Pa or less. An ATO porous electrode having an average transmittance of about 90% or more at ˜800 nm can be formed. Here, the average transmittance of the ATO porous electrode is the three-layer portion of the support substrate, the transparent electrode, and the ATO porous electrode. In the electrode structure in which the electrochromic dye is not supported on the ATO porous electrode. The transmittance for light having a wavelength of 400 nm to 800 nm is shown.

  FIG. 1 is a cross-sectional view illustrating a schematic configuration of an example of an electrochromic device according to an embodiment of the present invention.

  As shown in FIG. 1, an electrochromic device 10 has a display electrode structure including a transparent electrode 2 and a porous electrode 4 on which an electrochromic compound 3 described later is supported on a support substrate 1 made of a polymer. 11 and a counter electrode structure 12 including a transparent electrode 7 and a porous electrode 8 on which an organic radical compound 13 described later is supported on a support substrate 6 made of a polymer, with an electrolyte layer 5 interposed therebetween. It has the structure arranged facing each other. As will be described later, the porous electrodes 4 and 8 are made of a porous film having high transmittance formed by magnetron sputtering.

  The transparent electrodes 2 and 7 have a low resistance and are composed of thin layers densely formed on the support substrates 1 and 6, and a voltage for the oxidation-reduction reaction of the electrochromic compound 3 is applied. The porous electrodes 4 and 8 are excellent in adhesiveness with the transparent electrodes 2 and 7 and have high light transmittance. The porous electrodes 4 and 8 are formed at a relatively low temperature and sufficiently support an organic electrochromic compound and / or an organic radical compound. And have a sufficient specific surface area. In FIG. 1, the porous electrodes 4 and 8 are formed on both of the opposing transparent electrodes 2 and 7, but the present invention is not limited to this configuration, and only one electrode is necessary if necessary. A porous electrode may be formed, and the electrochromic compound 3 may be supported on the porous electrode. In order to make the response speed of coloring and decoloring sufficient, it is desirable that the porous electrodes 4 and 8 have as low resistance as possible. For example, when evaluated by a sheet resistance value [Ω / □], the porous electrodes 4 and 8 are porous. When the thickness of the counter electrode is 100 nm or more, it is preferably 100000 [Ω / □] or less. Further, when the film thickness is 1 μm or more, it is desirably 5000 [Ω / □] or less.

  First, formation of a porous electrode using a magnetron sputtering apparatus will be described.

  FIG. 2 is a diagram schematically showing a schematic configuration example of a magnetron sputtering apparatus in the embodiment of the present invention.

As shown in FIG. 2, in the magnetron sputtering apparatus 20 in the embodiment of the present invention, a rotation holder 24 on which targets 26 a and 26 b and a base 27 are mounted is disposed in a film forming chamber 21 evacuated by a vacuum pump 25. ing. When film formation is performed on the substrate 27, the rotary holder 24 is driven to rotate from the outside. When film formation is performed on the substrate 27, Ar gas and O ₂ gas are introduced into the film formation chamber 21 as necessary. The film forming chamber 21 includes an Ar gas mass flow controller 22 that controls the flow rate of Ar gas introduced into the film forming chamber 21, and an O ₂ gas that controls the flow rate of O ₂ gas introduced into the film forming chamber 21. _{A two-} gas mass flow controller 23, a diaphragm vacuum gauge 28 and an ionization vacuum gauge 29 for measuring the degree of vacuum inside the film forming chamber 21 are connected.

  The pressure (Pa) in the film forming chamber 21 is measured using a diaphragm vacuum gauge 28. A diaphragm vacuum gauge measures the amount of deformation of a thin metal film (diaphragm) stretched over a part of a container kept in a vacuum according to the degree of vacuum of the atmosphere, and measures the degree of vacuum with a strain gauge. Yes, it can be used from atmospheric pressure to low vacuum.

  The base body 27 provided on the anode and the targets 26a and 26b provided on the cathode face each other, and magnets 30a and 30b are disposed on the back portions of the targets 26a and 26b, respectively. Ar ions in plasma generated by applying a high voltage between the rotary holder 24 on which the base 27 is mounted and the targets 26a, 26b by the power sources 31a, 31b sputter the targets 26a, 26b. Particles sputtered from the targets 26 a and 26 b are deposited on the base 27.

The base 27 is a support substrate 1 or 6 made of a polymer on which dense transparent electrodes 2 and 7 such as an ITO film are formed, and the targets 26a and 26b are metal Sn targets or SnO ₂ targets and are doped with antimony. 2, ATO (antimony trioxide-tin oxide composite oxide) porous electrodes 4, 8 are formed on the transparent electrodes 2, 7 by the magnetron sputtering apparatus 20 shown in FIG. 2.

  A configuration in which a high voltage is applied between the rotary holder 24 on which the substrate 27 is mounted and the targets 26a and 26b and a voltage is indirectly applied between the transparent electrodes 2 and 7 and the targets 26a and 26b is a sliding electrode. It is also possible to apply power directly to the transparent electrodes 2 and 7 and apply a voltage between the transparent electrodes 2 and 7 and the targets 26a and 26b. This configuration improves the efficiency of plasma generation, Sputtering can be promoted, and the deposition rate of the sputtered particles on the transparent electrodes 2 and 7 can be increased.

The ATO porous electrodes 4 and 8 can be formed using either a metal Sn target or a SnO ₂ target. In the case of using a metal Sn target, the apparatus 20 is operated as a reactive DC magnetron sputtering apparatus that performs film formation while introducing O ₂ gas into the film formation chamber 21 using a direct current power source as the power supplies 31a and 31b. be able to. When using the SnO ₂ target, the apparatus 20 can be operated as a radio frequency (RF) magnetron sputtering apparatus using a high frequency power supply as the power supplies 31a and 31b.

  The distance between the base body 27 and the targets 26a and 26b is suitably 3.0 cm or more, and the deposition rate decreases as the distance increases.

In addition, when Sn is used as a target, the power supply to the target needs to be 200 W / 3 inches or less (4.5 W / cm ² or less because Sn has a low melting point. On the other hand, SnO ₂ is used as a target. When used, the power supply can be increased to the kW order (the film quality does not change with the magnitude of the power supply, but the deposition rate changes).

  In the example shown in FIG. 2, a configuration using metal Sn targets 26 a and 26 b is shown. The deposition rate of the porous film depends on the oxygen partial pressure and the total pressure, as will be described later.

  The ATO porous electrodes 4 and 8 can be formed on the transparent electrodes 2 and 7 by the magnetron sputtering apparatus shown in FIG. 2, and the display electrode structure 11 that functions as a display electrode in the electrochromic device functions as a counter electrode. The counter electrode structure 12 can be formed.

  In the above description, the example in which the ATO porous electrodes 4 and 8 are formed on the transparent electrodes 2 and 7 has been described. However, the transparent porous electrode formed on the transparent electrodes 2 and 7 is composed of a semiconductor layer. The semiconductor may be formed of a metal oxide or a metal oxide composite, and the metal may be any one of indium, tin, zinc, and aluminum.

  Next, the components of the electrochromic device will be sequentially described below.

<Support substrate>
As a material for the supporting substrates 1 and 6, generally, a material having sufficient heat resistance and high dimensional stability in the plane direction is suitable. In particular, in view of performing color display, a highly transparent material is desirable. Specific examples include glass materials and transparent resins. When a display device to be finally manufactured is flexible, it is particularly preferable to apply a thin transparent resin substrate.

  When the resin material is applied to the support substrates 1 and 6, for example, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyamide (PA), polysulfone (PS), polyethersulfone (PES), polyether Use polymer materials such as ether ketone (PEEK), polyphenylene sulfide (PPS), polycarbonate (PC), polyimide (PI), polymethyl methacrylate (PMMA), polystyrene, etc. Can do.

  As a specific example, a polyimide (PI) substrate (for example, trade name “Neoprim L” manufactured by Mitsubishi Gas Chemical Co., Ltd., heat resistant temperature: 285 degrees, light transmittance 90% (thickness 100 μm)), fluororesin substrate (heat resistant temperature: 250 degrees), polyethersulfone (PES) substrate (for example, trade name “Sumilite FS” manufactured by Sumitomo Bakelite Co., Ltd., heat-resistant temperature: 180 degrees, light transmittance 88% (thickness 550 nm)), polyethylene naphthalate (PEN) Examples include substrates (heat-resistant temperature: 160 degrees) and polyethylene terephthalate (PET) substrates (heat-resistant temperature: 140 degrees).

<Transparent electrode>
According to the known prior art, the transparent electrodes 2 and 7 are formed by applying and baking a predetermined electrode material to form a film. Examples of the electrode material constituting the transparent electrodes 2 and 7 include a mixture of In ₂ O ₃ and SnO ₂ , an ITO (Indium Tin Oxide) film, a GTO (Gallium Tin Oxide) film, SnO ₂ or In ₂ O _3. And a film coated with. An ITO film or a film coated with SnO ₂ or In ₂ O ₃ may be doped with Sn, Sb, F, etc., and the fluorine-doped tin oxide film is called an FTO film. In addition, MgO, ZnO, etc. are applicable. AZO (Aluminum doped Zinc Oxide) film in which Zn is doped with Al, GZO (Gallium doped Zinc Oxide) film in which ZnO is doped with gallium (Ga), IZO (Indium Zinc Oxide) film in which ZnO is doped with indium (In), etc. Can also be applied.

<Porous electrode>
Next, the porous electrode will be described. The porous electrode 4 constituting the display electrode structure 11 is preferably made of a material having a large surface area in order to obtain a high organic EC dye carrying function. Examples thereof include a porous shape having fine pores on the surface and inside, a lot shape, a wire shape, a mesoporous shape, and an aggregated particle shape. Moreover, in order to produce an organic EC device having a laminated structure, the porous electrode 4 needs to be transparent. Furthermore, in order to obtain an organic EC device capable of a high response speed, the porous electrode 4 needs to have a band structure that enables smooth electron transfer with the organic EC dye.

The porous electrode 4 can be formed of, for example, an oxide semiconductor, a complex oxide semiconductor, an organic semiconductor, or the like. Examples of the oxide semiconductor include TiO ₂ , SnO ₂ , Fe ₂ O ₃ , SrTiO ₃ , WO ₃ , ZnO, ZrO ₂ , Ta ₂ O ₅ , Nb ₂ O ₅ , V ₂ O ₅ , In ₂ O ₃ , Examples thereof include CdO, MnO, CoO, TiSrO ₃ , KTiO ₃ , Cu ₂ O, sodium titanate, barium titanate, and potassium niobate.

Examples of the complex oxide semiconductor include SnO ₂ —ZnO, Nb ₂ O ₅ —SrTiO ₃ , Nb ₂ O ₅ —Ta ₂ O ₅ , Nb ₂ O ₅ —ZrO ₂ , Nb ₂ O ₅ —TiO _2. , Ti—SnO ₂ , Zr—SnO ₂ , Sb—SnO ₂ , Bi—SnO ₂ , In—SnO _2, etc., and particularly TiO ₂ , SnO ₂ , Sb—SnO ₂ , and In—SnO ₂ are suitable. .

  Examples of the organic semiconductor include polythiophene, polypyrrole, polyacetylene, polyphenylene vinylene, and polyphenylene sulfide.

In order to finally configure the target electrochromic device for color display, it is optimal that the porous electrode is colorless and transparent. In particular, TiO ₂ , SnO ₂ , Sb—SnO ₂ , In by using -SnO _2, it is possible to produce a highly transparent porous electrode by a magnetron sputtering apparatus having a DC or RF power supply.

  Next, the porous electrode 8 will be described. The porous electrode 8 constituting the counter electrode structure 12 is composed of at least a metal oxide (intrinsic semiconductor or oxide semiconductor) made of indium, antimony, tin, zinc, or aluminum, or a composite made of multiple components of the metals. A metal oxide or composite oxide made of an oxide semiconductor, particularly antimony, is preferred.

  The porous electrode 8 constituting the counter electrode structure 12 has a large contact area with the electrolytic solution (electrolyte layer 5) and is preferably a porous film having a large specific surface area to support an organic radical compound described later. . Moreover, in order to produce an organic EC device having a laminated structure, the porous electrode 8 needs to be transparent. Furthermore, in order to obtain an organic EC device capable of a fast response, the porous electrode 8 needs to have a large electric capacity and a redox potential. In addition, the porous electrode 8 needs to have a band structure that enables a smooth redox reaction with the electrolytic solution (electrolyte layer 5). Furthermore, in order to produce a flexible EC device, it is necessary that the adhesion between the porous electrode 8 and the transparent electrode 7 be good.

  The porous electrode 8 is preferably formed by magnetron sputtering using a material mainly composed of antimony-tin or antimony trioxide-tin oxide composite oxide as a target. At this time, a DC power source or an RF power source can be applied as a power source. However, when a target material mainly composed of antimony-doped tin oxide or antimony trioxide-tin oxide composite oxide is used, it is preferable to use an RF power source.

  In magnetron sputtering, an oxygen gas is introduced into a film formation chamber (vacuum chamber) 21 in which film formation is performed in addition to an inert gas for sputtering. The amount of oxygen gas introduced is 10% or more and 90% or less in terms of partial pressure. When the partial pressure of oxygen gas is 10% or less, the proportion of Sn atoms (or Sb atoms) that do not have a bond with O atoms increases, and properties close to metals are exhibited. On the other hand, if it is 90% or more, the number of O atoms is excessive with respect to Sn atoms (or Sb atoms), which is not preferable because it is far from suitable p-type semiconductor properties.

  The total pressure in the film forming chamber 21 is set to 0.5 Pa or more and 6.0 Pa or less. If the total pressure in the film forming chamber 21 is 0.5 Pa or less, a porous structure is not formed, which is not preferable. On the other hand, when the pressure is 6.0 Pa or more, a heterogeneous pore structure is formed on the order of several hundred nanometers to micrometers, so that the amount of the organic radical compound 13 supported is low and the optical transparency is also deteriorated. Therefore, it is not preferable.

  The surface temperature of the film-forming surface at the time of sputtering shall be selected according to the heat resistance (glass transition point) of the material applied as a support substrate. The surface temperature can be adjusted by the sputtering rate, that is, mainly by sputtering conditions such as power output. When a plastic material is applied to the support substrate, the surface temperature is preferably 300 ° C. or less, and more preferably the glass transition point or softening point of the applied plastic material.

<Electrochromic compound (organic EC dye)>
Next, the organic EC dye 3 will be described. It is assumed that the organic EC dye 3 is carried on the surface of the porous electrode 4 and the fine pores inside. Any material known as an electrochromic dye can be applied to the organic EC dye 3. However, it is preferable that the molecular structure has a functional group so that the organic EC dye 3 is supported on the porous electrode 4. Specific examples of functional groups that act as adsorbing groups for adsorbing the organic EC dye 3 to the porous electrode 4 include acidic groups such as carboxyl groups, sulfonic acid groups, and phosphonic acid groups, amino groups, metal alkoxides, metal halides, and the like. Is mentioned. As the organic EC dye 3, only a single compound may be used, or a plurality of compounds may be mixed and used.

  Although FIG. 1 shows a configuration in which the organic EC dye 3 is supported only on the porous electrode 4 on the display electrode structure 11 side, the present invention is not limited to the configuration example shown in FIG. The porous electrode 8 on the counter electrode structure 12 side may be configured to carry an organic EC dye similarly to the porous electrode 4. However, in such a case, a material that reverses the oxidation / reduction reaction in the color development / decoloration reaction of the organic EC dye in both electrode structures 11 and 12 is selected.

  For example, when the organic EC dye carried on the porous electrode material 4 becomes a radical state by the reduction reaction and develops color, the porous electrode 8 has the same color tone as the dye carried on the porous electrode 4 in a steady state. Select an organic EC dye that develops color by oxidation reaction.

  In this way, by adopting a configuration in which the organic EC dye is supported on both electrode structures 11 and 12, the color display density can be made sufficiently high, and in the finally obtained electrochromic device, color development is achieved. Clarification and image clarity can be improved.

  Specific examples of the organic EC dye (electrochromic compound) 3 are shown in the following formulas (1) to (13). In the following formulae, Me is a methyl group. The compounds represented by the following formulas (1) and (5) are 4,4′-bipyridine derivatives, the compounds represented by the following formula (2) are 2,5-bis (4-pyridyl) furan derivatives, the following formula ( The compound represented by 3) is a 2,5-bis (4-pyridyl) thiophene derivative, the compound represented by the following formula (4) is a 2,5-bis (4-pyridyl) -1H-pyrrole derivative, The compound represented by (6) is a 3,4'-bipyridine derivative, and the compounds represented by the following formulas (7), (11), (12), and (13) are 4,4 '-(1,4- Phenylene) dipyridine derivative, a compound represented by the following formula (8) is a bis (4-pyridyl) ketone derivative, and a compound represented by the following formula (9) is 4,4′-bis (4-pyridyl)- Benzophenone derivative, represented by the following formula (10) Compounds is the is the 2,5-bis (4-pyridyl) -1,3,4-oxadiazole derivatives can be regarded respectively.

<Supporting electrochromic compound (organic EC dye) on porous electrode>
Prior to loading the organic EC dye on the porous electrode, the porous electrode is treated with UV ozone. The UV ozone treatment apparatus used (Samco Co., Ltd., UV-300) uses a low-pressure mercury lamp that emits emission lines of 185 nm and 254 nm as a light source, and the dissociation reaction of oxygen molecules is caused by 185 nm (<240 nm) rays (O ₂ → O ( ³ P) + O ( ³ P)). The generated triplet ground oxygen atom (O ( ³ P)) reacts with oxygen molecules to generate ozone (O ( ³ P) + O ₂ → O ₃ ). Ozone has an absorption band in the vicinity of 260 nm, and a dissociation reaction occurs due to the 254 nm line. This dissociation reaction generates singlet excited oxygen atoms (O ₃ → O ₂ + O ( ¹ D)). This excited oxygen atom oxidizes the C—H bond on the surface of the porous electrode excited by ultraviolet rays (184 nm and 254 nm), and the surface of the porous electrode has a hydrophilic functional group (—CO, —CHO, — COO, -COOH, etc.).

  UV ozone treatment decomposes and removes organic substances, water, etc. in the air that are physically or chemically adsorbed on the surface of the porous electrode, and adsorbs the adsorbing groups of the organic EC dye (forms hydrogen bonds) And the amount of organic EC dye adsorbed on the porous electrode can be increased.

  Next, a method for supporting the organic EC dye on the porous electrode 4 will be described. For example, conventionally known techniques such as a method of adsorbing on the surface of the porous electrode 4 and a method of chemically bonding the surface of the porous electrode and the organic EC dye can be applied. As specific methods, a dry process such as a vacuum deposition method, a coating method such as spin coating, an electric field deposition method, an electric field polymerization method, a natural adsorption method of immersing in a solution of a compound to be supported, etc. can be applied. A natural adsorption method that is not required and a method in which an organic EC dye is chemically bonded to the surface of the porous electrode are suitable.

  As a natural adsorption method, a method is prepared by dissolving a predetermined organic EC dye in a predetermined solvent to prepare a solution, and dipping the solution after drying the transparent substrate on which the porous electrode 4 is formed, The method of apply | coating the solution in which the predetermined | prescribed organic EC pigment | dye was melt | dissolved to the porous electrode 4 is mentioned. In this natural adsorption method, in order to securely support the organic EC dye on the porous electrode 4, it is necessary to introduce a functional group having adsorptivity into the chemical structure of the organic EC dye.

  The functional group having the adsorptivity is appropriately selected according to the material of the porous electrode 4. For example, when the porous electrode 4 is made of an oxide semiconductor, the adsorptive functional group in the chemical structure of the organic EC dye includes a phosphonic acid group, a sulfonic acid group, a carboxyl group, a hydroxy group, an amino group, etc. Is preferably introduced in advance.

  The functional group may be introduced directly into the skeleton of the chemical structure of the organic EC dye, or may be introduced by forming a bond via another predetermined functional group. In the case of passing through a predetermined functional group, for example, an adsorptive functional group can be introduced through an alkyl group, a phenyl group, an ester, an amide group or the like.

  Examples of the solvent for dissolving the organic EC dye include water, alcohol, acetonitrile, propionitrile, halogenated hydrocarbons, ethers, dimethyl sulfoxide, N, N-dimethylformamide, N-methylpyrrolidone, esters, Carbonates, ketones, hydrocarbons and the like can be applied. These may be used singly or may be mixed as appropriate.

  A method of supporting the electrochromic compound on the surface of the porous electrode by chemical bonding is also suitable. When the organic EC dye is chemically bonded to the surface of the porous electrode 4, a predetermined functional group may be interposed between the surface of the porous electrode 4 and the organic EC dye skeleton. For example, functional groups such as an alkyl group, a phenyl group, an ester, and an amide can be mentioned.

  Further, after the surface of the porous electrode 4 is modified with a silane coupling agent or the like, an organic EC dye may be chemically bonded and formed. By such surface modification, when the organic EC dye forms a chemical bond with the material of the porous electrode 4, the binding force of the organic EC dye becomes stronger. This is advantageous in the case of using a high one, and the material selectivity of the organic EC dye is enhanced, and the durability of the electrochromic device is improved.

<Electrolyte layer>
The electrolyte layer 5 has a configuration in which a supporting electrolyte is dissolved in a solvent. Examples of the supporting electrolyte include lithium salts such as LiCl, LiBr, LiI, LiBF ₄ , LiClO ₄ , LiPF ₆ , and LiCF ₃ SO ₃ , potassium salts such as KCl, KI, and KBr, and NaCl, NaI, for example. And sodium salts such as NaBr, and tetraalkylammonium salts such as tetraethylammonium borofluoride, tetraethylammonium perchlorate, tetrabutylammonium borofluoride, tetrabutylammonium perchlorate, and tetrabutylammonium halide.

  A known redox compound may be added to the electrolyte layer 5 as necessary. As the redox substance, for example, a ferrocene derivative, a tetracyanoquinodimethane derivative, a benzoquinone derivative, a phenylenediamine derivative, or the like can be applied.

  As said solvent, the thing which melt | dissolves a support electrolyte and does not melt | dissolve the organic EC pigment | dye mentioned above is selected. For example, it is appropriately selected from water, acetonitrile, dimethylformamide, propylene carbonate, dimethyl sulfoxide, propylene carbonate and the like.

Further, a so-called matrix material may be applied to the electrolyte layer 5. Matrix material can be appropriately selected depending on the purpose, for example, skeletal unit _{respectively, - (CC-O) n} -, - (CC (CH 3) -O) n -, - (CC-N ) _N- or-(C-C-S) _n- , polyethylene oxide, polypropylene oxide, polyethyleneimine, and polyethylene sulfide. Note that these skeleton units may have a branched structure as the main chain structure. Polymethyl methacrylate, polyvinylidene fluoride, polyvinylidene chloride, polycarbonate, and the like are also suitable.

  The electrolyte layer 5 may be a polymer solid electrolyte layer. In this case, it is preferable to add a predetermined plasticizer to the polymer of the matrix material. As the plasticizer, when the matrix polymer is hydrophilic, water, ethyl alcohol, isopropyl alcohol, and a mixture thereof are preferable. When the matrix polymer is hydrophobic, propylene carbonate, dimethyl carbonate, ethylene carbonate, γ- Butyrolactone, acetonitrile, sulfolane, dimethoxyethane, ethyl alcohol, isopropyl alcohol, dimethylformamide, dimethyl sulfoxide, dimethylacetamide, n-methylpyrrolidone, and mixtures thereof are preferred.

<Organic radical compound>
Next, the organic radical compound 13 will be described. This is a compound having a functional group represented by the following formula (14). For the porous electrode 8, the organic radical compound 13 is supported on the porous electrode 8 in order to improve the storage capacity of the electrode. As the organic radical compound 13, the compounds described later can be used. The organic radical compound 13 in FIG. 1 is a material having a function of charging the opposite electrode structure 12 to a charge opposite to the state when the organic EC dye 3 of the display electrode structure 11 is colored, thereby providing a color display function. Is increased.

  Specific examples of the organic radical compound 13 having a functional group of the formula (14) are shown in the following formulas (15) to (57).

<Supporting organic radical compound on porous electrode>
As in the case of loading the organic dye on the porous electrode, prior to loading the organic radical compound on the porous electrode, the porous electrode is subjected to UV ozone treatment, and the surface of the porous electrode is hydrophilic containing oxygen. A porous electrode can be formed by forming functional groups (-CO, -CHO, -COO, -COOH, etc.) and increasing the surface sites on which the adsorbing groups of organic radical compounds are adsorbed (forming hydrogen bonds). The amount of the organic radical compound adsorbed on can be increased.

  Similar to the organic EC compound 3 described above, the organic radical compound 13 has an adsorbing group for adsorbing to the porous electrode 8 in the chemical structure. Specific examples of the adsorbing group include an acidic group such as a carboxyl group, a sulfonic acid group, and a phosphonic acid group, an amino group, a metal alkoxide, a metal halide, and the like, and a phosphonic acid group is particularly preferable. Similar to the organic EC compound 3 supported on the porous electrode 4, the organic radical compound 13 has a functional group that acts as an adsorbing group, so that the organic EC compound 3 is supported on the porous electrode 4. In the same manner, the organic radical compound 13 can be supported on the porous electrode 8. The organic radical compound 13 may be a single type of compound or a mixture of a plurality of types of compounds.

  A method for manufacturing the electrochromic device of the present invention will be described. First, the display electrode structure 11 is produced. A transparent electrode 2 is formed on a support substrate 1 having a predetermined material and film thickness, and then a porous electrode 4 is formed. After that, for example, the dye is supported by being immersed in an organic EC dye aqueous solution, and a washing process and a drying process are performed with an ethanol solution.

  Subsequently, the counter electrode structure 12 is produced by forming the transparent electrode 7 on the support substrate 6 having a predetermined material and film thickness, and then forming the porous electrode 8. Next, the organic radical compound 13 is supported on the porous electrode 8.

  In addition, about the detailed formation method of the porous electrodes 4 and 8, it shall follow the method mentioned above. The electrode for supporting the organic EC dye is also appropriately selected to be both or one. When organic EC dyes are supported on both porous electrodes, different types of EC dyes are used, the porous electrode 4 is supported with a color developing upon reduction, and the porous electrode 8 is colored with oxidation. Support what you want to carry.

  Next, a solution for the electrolyte layer is prepared. Subsequently, the display electrode structure 11 and the counter electrode structure 12 are bonded together using a predetermined adhesive. At this time, an injection port is formed in a part so that an electrolytic solution can be injected in a later process. . Thereafter, an electrolytic solution is injected from the injection port and sealed with a resin adhesive, whereby an electrochromic device having an opposing electrode structure is manufactured.

  Next, a display method using the electrochromic device 10 of the present invention will be described.

  In the electrochromic device 10 of FIG. 1, the surface of the porous electrode 4 carries a predetermined compound that is an organic EC compound that does not absorb in the visible region in a steady state.

  A predetermined lead wire is connected to the pair of electrode structures 11 and 12 constituting the electrochromic device 10 to constitute a display device. When a predetermined voltage is applied through a predetermined lead wire, electrons are transferred between the porous electrode 4 and the organic EC compound supported on the porous electrode 4, and an electrochemical reduction reaction occurs in the organic EC compound. Color develops in the radical state of.

  The porous electrode 8 on the counter electrode structure 12 side is charged with a charge opposite to that of the organic EC dye (when the organic EC dye is charged with a negative charge by a reduction reaction, the porous electrode 8 is + Charge) and enhance and stabilize the coloring function by the dye.

  An example of the thickness of each layer constituting the electrochromic device shown in FIG. 1 is as follows.

Thickness of support substrate 1 = 10 μm to 10 mm,
Support substrate 6 thickness = 10 μm to 10 mm,
The thickness of the transparent electrode 2 = 40 nm to 1000 nm,
The thickness of the transparent electrode 7 = 40 nm to 1000 nm,
The thickness of the porous electrode 4 = 1.5 μm to 30 μm,
Thickness of porous electrode 8 = 1.5 μm to 30 μm,
Display electrode structure 11 thickness = 11 μm to 11 mm,
The thickness of the counter electrode structure 12 = 11 μm to 11 mm,
The distance between the transparent electrode 2 and the transparent electrode 7 is 1 μm to 1 mm.

  The electrochromic device of the present invention is not limited to the configuration shown in FIG. 1, but can be applied to a device configuration capable of multicolor display. That is, an electrochromic compound that has the same structure as the electrochromic structure shown in FIG. 1 and that is converted into a radical state by an electrochemical reaction and develops magenta (M), yellow (Y), and cyan (C). An electrode structure is prepared by carrying it on a predetermined porous electrode, and by using these three layers, a magenta (M), yellow (Y), and cyan (C) laminated structure is formed, thereby providing a color-decoloring display. An electrochromic device with full color display that can be performed reversibly is obtained.

  As an electrochromic compound (organic EC dye), a dye having an absorption maximum in the yellow region (range of 430 to 490 nm), magenta region (range of 500 to 580 nm), and cyan region (range of 600 to 700 nm) should be used. Is desirable.

  The electrochromic device for full-color display sandwiches an electrolyte layer so that a pair of electrode structures (a display electrode structure and a counter electrode structure) having at least a transparent electrode formed on a support substrate face each other. A porous electrode carrying an electrochromic compound is formed on at least the transparent electrode of the display electrode structure among the transparent electrodes constituting the pair of electrode structures, Color development can be performed by controlling the voltage applied between the electrode structures, and (a) a porous electrode carrying an electrochromic compound is formed and reversible color development of cyan is performed. An electrochromic device structure capable of performing reversible color development of yellow, and (c) possible magenta. It is formed by laminating three element structures of an electrochromic element structure that can produce a typical color, and displays a full color image as a whole by controlling the voltage applied to each electrochromic element structure can do.

  FIG. 3 is a cross-sectional view illustrating a schematic configuration of an example of an electrochromic device capable of performing color display according to an embodiment of the present invention.

  Each of the electrochromic element structures 10A, 10B, and 10C shown in FIG. 3 has the same configuration as the electrochromic device shown in FIG.

  The electrochromic device capable of performing color display shown in FIG. 3 includes: (a) a first support substrate (support substrates 1a, 1b, 1c), and a first transparent substrate formed on the first support substrate. Display electrode structures 11a, 11b including electrodes (transparent electrodes 2a, 2b, 2c) and a first porous electrode (porous electrodes 4a, 4b, 4c) formed on the first transparent electrode, 11c, (b) a second support substrate (support substrates 6a, 6b, 6c), a second transparent electrode (transparent electrodes 7a, 7b, 7c) formed on the second support substrate, and this Counter electrode structures 12a, 12b, 12c including second porous electrodes (porous electrodes 8a, 8b, 8c) formed on the second transparent electrode, and (c) display electrode structures 11a, 11b, 11 and the counter electrode structures 12a, 12b, and 12c. Sandwiched the electrolyte layer 5a, it is equipped 5b, and 5c.

  The first transparent electrode (2a, 2b, 2c) and the second transparent electrode (7a, 7b, 7c) are arranged to face each other through the electrolyte layers 5a, 5b, 5c, and the organic EC dye (3a, 3b, 3c) are carried on the first porous electrodes (4a, 4b, 4c), and organic radical compounds (13a, 13b, 13c) are carried on the second porous electrodes (8a, 8b, 8c). Electrochromic element structures 10A, 10B, and 10C are formed.

  The electrochromic element structures 10A, 10B, and 10C are stacked, and the first transparent electrodes (2a, 2b, and 2c) and the second transparent electrodes (7a, 10c) of the electrochromic element structures 10A, 10B, and 10C are stacked. By controlling the voltage applied between 7b and 7c), reversible color erasing with an electrochromic compound can be performed. An organic EC device that performs color display can be manufactured by a laminated structure of transparent electrochromic element structures 10A, 10B, and 10C.

  The organic EC dyes (3a, 3b, 3c) carried on the first porous electrodes (4a, 4b, 4c) of the electrochromic element structures 10A, 10B, 10C, respectively, are viewed from above in FIG. Then, magenta, yellow, and cyan.

  The electrochromic compound used in the electrochromic device shown in FIG. 1 and FIG. 3 is in a decolored state without absorption in the visible light region when no voltage is applied, and visible when a voltage is applied. A compound that absorbs in the light region and becomes a colored state. Conversely, when a voltage is applied, the compound is in a decolored state with no absorption in the visible light region, and absorbs in the visible light region when no voltage is applied. It may be any of a compound that exhibits a colored state or a compound that can be in a multi-colored state that varies in color depending on the magnitude of applied voltage, and can be appropriately selected according to the purpose. A full color image can be displayed by controlling the voltage applied to each of the bodies 10A, 10B, and 10C.

  In addition, in the electrochromic device shown in FIGS. 1 and 3, in order to perform active matrix driving, a first transparent electrode (transparent electrodes 2, 2a) is provided on a first support substrate (support substrates 1, 1a, 1b, 1c). 2b, 2c) are formed as fractions, that is, a plurality of fractions that are mutually independent so as to correspond to each pixel are formed in a matrix, and a first porous electrode ( A porous electrode 4, 4a, 4b, 4c) is formed, and a thin film transistor (TFT) connected by a gate line and a source line is formed and arranged on the first transparent electrode corresponding to each fraction. It can also be set as the apparatus which has. According to this apparatus, by controlling the voltage applied to the thin film transistor, it is possible to control the color development / decoloration in the fraction corresponding to each pixel of the electrochromic element structures 10A, 10B, and 10C.

Further, in the electrochromic device shown in FIG. 1, the transparent electrode 2 is fractionated and formed so as to correspond to the pixels, that is, the first, second and second corresponding to cyan, magenta, and yellow for performing active matrix driving. A matrix-like transparent electrode 2 composed of a plurality of fractions composed of the third fraction is formed on the support substrate 1, and a porous electrode 4 is formed on the first, second and third fractions, Electrochromic compounds capable of coloring cyan, magenta, and yellow are supported on the porous electrodes 4 formed on the first, second, and third fractions, respectively, and the first, second, and third fractions are supported. Correspondingly, a device having a configuration in which a thin film transistor connected by a gate line and a source line is formed and arranged on the transparent electrode 2 can be provided. According to this apparatus, by controlling the voltage applied to the thin film transistor, it is possible to control the color development / decoloration in the first, second, and third fractions corresponding to the respective pixels.
The

  Next, specific examples of the electrochromic device of the present invention and a comparative example thereof will be described.

Example [Production Example of Electrochromic Device: Evaluation Example]
(Preparation of display electrode structure): Display electrode structure used in examples and comparative examples described later An ITO film having a surface resistance of 13Ω / □ on a support substrate 1 made of polyethylene naphthalate (PEN) having a thickness of 150 μm. (Transparent electrode 2) was formed by a coating / firing method to produce a base body 27 (ITO-PEN substrate).

  The total pressure in the film forming chamber 21 of the magnetron sputtering apparatus 20 shown in FIG. 2 is 2.0 Pa, the partial pressure of oxygen gas is 50%, the partial pressure of argon gas is 50%, and a 4-inch Sn target is used. Using two simultaneously, the power output to each target was set to 100 W (total output was 200 W). The distance between the targets 26a and 26b and the substrate 7 was 7.5 cm. Reactive RF magnetron sputtering was performed to form a 2.6 μm thick porous tin oxide film on the surface of the ITO film (transparent electrode 2). The surface temperature of the substrate (PEN) 1 during film formation was 150 ° C. or less.

  Subsequently, the ITO-PEN substrate on which the porous electrode 4 made of a porous tin oxide film is formed is subjected to UV ozone treatment, and then is added to a 2 mM aqueous solution of an organic EC dye represented by the above formula (12) at 40 degrees below. The organic EC dye was adsorbed by immersion for 24 hours. Thereafter, washing treatment with an ethanol solution and drying treatment by nitrogen blowing were performed to obtain a display electrode structure.

[Preparation of First Counter Electrode Structure] First counter electrode structure used in examples to be described later On a support substrate 6 made of polyethylene naphthalate (PEN) having a thickness of 150 μm, the surface resistance is 13Ω / □. A substrate (base 27) (ITO-PEN substrate) on which an ITO film (transparent electrode 2) was formed was prepared.

The degree of vacuum in the film forming chamber 21 of the magnetron sputtering apparatus 20 shown in FIG. 2 is 7.21 × 10 ⁻⁴ Pa, the total pressure is 4.0 Pa (the partial pressure of oxygen gas with respect to the total pressure is 50%, and the argon gas and pressure was set at 50%.), a _{4wt% -Sb 2 O 3 / 96wt} % -SnO 2 target 3 inch with one, set the power output to the target to 150 W. The distance between the targets 26a and 26b and the substrate (base 27) was 7.5 cm.

  Sputtering was performed on the ITO film surface for 570 minutes to form an antimony-doped tin oxide film (ATO porous electrode) having a thickness of 4.5 μm. The film formation rate was 470 nm / hour, and the substrate surface temperature during film formation was 120 ° C. or less.

  Subsequently, the ITO-PEN substrate on which the porous electrode 8 made of an ATO film was formed was subjected to UV ozone treatment, and then 4-phosphosoxy-TEMPO (organic radical compound (TEMPO: 2, 2) represented by the above chemical formula (22). , 6,6-Tetramethylpiperidine 1-oxyl))) soaked in an aqueous solution of 5 mM at 40 ° C. for 24 hours, and the organic radical compound was applied to the ATO porous electrode. Adsorbed. Thereafter, washing treatment with an ethanol solution and drying treatment by nitrogen blowing were performed to obtain a first counter electrode structure.

[Preparation of Second Counter Electrode Structure] Second counter electrode structure used in Comparative Example 1 described later On a support substrate 6 made of polyethylene naphthalate (PEN) having a thickness of 150 μm, the surface resistance is 13Ω / □. The board | substrate (base | substrate 27) (ITO-PEN board | substrate) with which ITO film | membrane (transparent electrode 2) was formed was produced.

The degree of vacuum in the film forming chamber 21 of the magnetron sputtering apparatus 20 shown in FIG. 2 is 3.25 × 10 ⁻⁴ Pa, the total pressure is 0.25 Pa (the partial pressure of oxygen gas with respect to the total pressure is 50%, the fraction of argon gas and pressure was set at 50%.), a _{4wt% -Sb 2 O 3 / 96wt} % -SnO 2 target 3 inch with one, set the power output to the target to 150 W. The distance between the targets 26a and 26b and the substrate (base 27) was 7.5 cm.

  Sputtering was performed on the ITO film surface for 480 minutes to form an antimony-doped tin oxide film (ATO porous electrode) having a thickness of 4.2 μm. The film formation rate was 525 nm / hour, and the substrate surface temperature during film formation was 120 ° C. or less.

  Subsequently, the ITO-PEN substrate on which the porous electrode 8 made of an ATO film is formed is subjected to UV ozone treatment, and then added to a 5 mM aqueous solution of 4-Phosphonooxy-TEMPO represented by the chemical formula (22) at 40 ° C. for 24 hours. The organic radical compound was adsorbed on the ATO porous electrode by dipping. Thereafter, washing treatment with an ethanol solution and drying treatment by nitrogen blowing were performed to obtain a second counter electrode structure.

[Production of Third Counter Electrode Structure] Three counter electrode structures used in Comparative Example 2 described later On a support substrate 6 made of polyethylene naphthalate (PEN) having a thickness of 150 μm, the surface resistance is 13Ω / □. A substrate (base 27) (ITO-PEN substrate) on which an ITO film (transparent electrode 2) was formed was prepared.

The degree of vacuum in the film forming chamber 21 of the magnetron sputtering apparatus 20 shown in FIG. 2 is 3.25 × 10 ⁻⁴ Pa, the total pressure is 2.0 Pa (the partial pressure of oxygen gas with respect to the total pressure is 0%, the argon gas is divided) and pressure was set to 100%.), a _{4wt% -Sb 2 O 3 / 96wt} % -SnO 2 target 3 inch with one, set the power output to the target to 150 W. The distance between the targets 26a and 26b and the substrate (base 27) was 7.5 cm.

  Sputtering was performed on the surface of the ITO film for 450 minutes to form an antimony-doped tin oxide film (ATO porous electrode) having a film thickness of 4.7 μm. The film formation rate was 625 nm / hour, and the substrate surface temperature during film formation was 120 ° C. or less.

  Subsequently, the ITO-PEN substrate on which the porous electrode 8 made of an ATO film is formed is subjected to UV ozone treatment, and then added to a 5 mM aqueous solution of 4-Phosphonooxy-TEMPO represented by the chemical formula (22) at 40 ° C. for 24 hours. The organic radical compound was adsorbed on the ATO porous electrode by dipping. Thereafter, a washing treatment with an ethanol solution and a drying treatment by nitrogen blowing were performed to obtain a third counter electrode structure.

[Fabrication of Fourth Counter Electrode Structure] Fourth counter electrode structure used in Comparative Example 3 to be described later On a support substrate 6 made of polyethylene naphthalate (PEN) having a thickness of 150 μm, the surface resistance is 13Ω / □. The board | substrate (base | substrate 27) (ITO-PEN board | substrate) with which ITO film | membrane (transparent electrode 2) was formed was produced.

  An antimony-doped tin oxide (ATO) having a primary particle size of 20 nm is dispersed in water in an amount of 20% by weight to prepare a slurry, and polyethylene glycol is dissolved in this slurry at a ratio of 5% by weight to form a paint. Prepared. This paint was applied on the ITO film by a squeegee method. Subsequently, an ITO-PEN substrate on which a porous electrode made of antimony-doped tin oxide (ATO) having a film thickness of 14 μm was formed by performing a drying treatment at 80 ° C. for 15 minutes using a hot plate.

Subsequently, the ITO-PEN substrate on which the porous electrode 8 made of an ATO film is formed is subjected to UV ozone treatment, and then added to a 5 mM aqueous solution of 4-Phosphonooxy-TEMPO represented by the chemical formula (22) at 40 ° C. for 24 hours. The organic radical compound was adsorbed on the ATO porous electrode by dipping. Thereafter, a washing treatment with an ethanol solution and a drying treatment by nitrogen blowing were performed to obtain a fourth counter electrode structure.
(Preparation of solution for electrolyte)
A solution obtained by dissolving 0.1 mol / L of lithium perchlorate in gamma-butyrolaclone, dehydrating and degassing was prepared.

[Lamination of electrode structure]
The first to fourth counter electrode structures 12 (the substrate on which the porous electrode 8 on which the organic radical compound 13 is adsorbed) and the display electrode structure 11 are bonded to each other with a thermoplastic film having a thickness of 50 μm. Bonding was performed at 90 degrees using an agent. At this time, an injection port was formed in a part so that the electrolyte solution could be injected in a later step.

[Injection of electrolyte solution]
An electrolyte solution was injected, and then an injection port was sealed with an epoxy thermosetting resin, and an electrochromic device including an electrode structure facing each other with the electrolyte layer sandwiched therebetween was completed.

Example 1
The basic physical properties of the ATO porous electrode in the first counter electrode structure described above were evaluated by X-ray diffraction, field emission scanning electron microscope (FE-SEM), nitrogen adsorption / desorption measurement, and absorption spectrum measurement. Below, an evaluation result is demonstrated.

  FIG. 4 is a diagram showing an X-ray diffraction pattern of a porous electrode according to an embodiment of the present invention, where the vertical axis represents diffraction intensity (cps) and the horizontal axis represents each diffraction (2θ (degrees)).

  As shown in FIG. 4, in the X-ray diffraction pattern of the ATO film (porous electrode), (110), (101), (200), (211), due to the rutile phase tin oxide that is tetragonal, The diffraction peaks of (002) and (112) were observed. From this, it was found that the crystal structure of the ATO film formed on the transparent electrode was mainly tin oxide.

  FIG. 5 is a diagram showing an FE-SEM photograph (magnification: 150,000) of the surface of the porous electrode according to an embodiment of the present invention.

  FIG. 6 is a diagram showing an FE-SEM photograph (magnification 22,000) of a cross section of a porous electrode according to an example of the present invention.

  As apparent from the field emission scanning electron microscope (FE-SEM) photographs shown in FIGS. 5 and 6, the ATO film formed by magnetron sputtering has a densely assembled diameter from the surface FE-SEM image. Nanoparticle-like morphology of about 50 nm to 100 nm was observed, and it was found from a cross-sectional FE-SEM image that it was composed of columnar bodies having a diameter of about 100 nm grown in a direction perpendicular to the support substrate. As will be described later, the ATO film was found to have mesoscale pores from the results of measurement of nitrogen adsorption / desorption isotherms.

SnO _2: Sb is the uncharged Sn or Sb, oxygen molecules O ₂ or oxygen molecular ions O ₂ ^- is formed by the reaction of (or oxygen radicals O ^·), of the films grown on the surface of the ITO film Accelerated particles (atoms) collide with the outermost convex part, and the convex part grows selectively, the convex part grows more convex, the concave part remains difficult to grow, and is a collection of columnar bodies It is considered that an ATO film having a columnar structure formed from the body was formed.

  In addition, the higher the pressure, the lower the energy of the colliding particles (atoms), so it is difficult to diffuse on the collided convex surface, and the crystalline particles are randomly sputtered on a minute scale on the column surface. (Or atoms) accumulate, and mesoscale pores are formed inside the columnar structure. In this manner, a columnar body is formed as a whole by the deposition of the crystalline particles sputtered from the target, and an ATO film having a columnar structure is formed by the aggregate. In the pressure range of 0.5 Pa to 6.0 Pa, a columnar body having mesoscale pores is formed, and it is considered that an ATO film having a columnar structure is easily formed.

  FIG. 7 is a diagram showing an FE-SEM photograph of a cross section of a porous electrode according to an embodiment of the present invention. The magnifications of the SEM photographs shown in FIGS. 7 (A) and 7 (B) are 330,000, respectively. 150,000.

  As can be seen from the cross-sectional FE-SEM image shown in FIG. 7, it can be seen that mesoscale pores exist inside the columnar structure. As described above, the porous electrode formed by magnetron sputtering is a mesoporous electrode characterized by having mesoscale pores inside the columnar body in addition to the gap between the columnar bodies grown perpendicular to the support substrate. is there. A portion assumed to be a typical mesoscale pore is indicated by an arrow in FIG. This mesoporous electrode is useful for adjusting the charge balance in the electrolyte solution during color development of the display element, has a large contact area with the electrolyte, and is suitable for adjusting the charge balance. In addition, it is possible to increase the amount of an organic radical compound having a nitrooxy radical group (which functions to lower the potential necessary for color development) on the mesoporous electrode.

Since oxygen is used when forming an ATO porous electrode on the ITO film surface by magnetron sputtering, a reaction between the generated plasma and oxygen occurs. Therefore, a singlet excited oxygen atom O ( ¹ D) is formed by a dissociation reaction due to collision between electrons and oxygen molecules (e ⁻ + O ₂ → O ( ³ P) + O ( ¹ D) + e ⁻ , e ⁻ + O. ( ³ P) → O ( ¹ D) + e ⁻ ). Due to the attack of the singlet excited oxygen atoms on the material surface, relatively weak chemical bonds on the material surface are dissociated. In addition, since the excited oxygen atoms are likely to react on the material surface because of the reduced pressure, the functional group on the substrate surface is dissociated near the outermost surface of the substrate at the start of magnetron sputtering film formation, and the substrate and the porous solid are separated. Form chemical bonds.

  That is, at the start of magnetron sputtering film formation, the ITO surface is modified by excited oxygen atoms, and a highly reactive hydrophilic group is formed on the ITO surface, so that a chemical bond between ITO, Sn (or Sb), and O is formed. Since the film formed with the chemical bond between ITO, Sn (or Sb) and O grows in a surface form reflecting the smoothness of the ITO surface, it is in the nanometer scale order of ITO and ATO. A uniform dense film is formed as an intermediate layer on the ITO surface. Further, when the magnetron sputtering film formation is advanced, the columnar body grows on the intermediate layer as described above, the intermediate layer is formed on the ITO-PEN substrate, and the columnar body grows further on the intermediate layer. An ATO film is formed in a state accompanied by a change in shape in the direction.

  As a result, a film having high adhesion with ITO was obtained, and it was confirmed that even if the ITO-PEN substrate on which the ATO porous electrode was formed was bent, the ITO film and ATO film were not peeled off, and the adhesion was improved. Improved durability.

  When an ATO film is formed, as the atomic layer is deposited, the shape changes as described above. Therefore, the lower layer part (the intermediate layer) of the ATO film and the upper layer part above the ATO film are in mesoscale order. The form of is very different. Further, the thickness of the dense film (the above intermediate layer) is considered to depend on the output during sputtering.

  FIG. 8 is a diagram showing an FE-SEM photograph (magnification: 1,1000, 3 kV) of the cross section of the interface between the porous electrode and the substrate according to the embodiment of the present invention.

  FIG. 8 is a cross-sectional FE-SEM image in which an ATO porous film is formed on an amorphous glass substrate and includes an interface portion, and is approximately smooth with a thickness of about 25 nm at the interface between the grown porous film and the glass substrate. A dense film (intermediate layer) was observed.

  Nitrogen adsorption / desorption isotherm is known as a method for evaluating the pore structure of porous membranes, and it can be used to evaluate the specific surface area, pore size distribution, and pore volume. Useful. The specific surface area is a surface area per unit weight and can be measured using physical adsorption of an inert gas such as nitrogen gas.

As a pretreatment of the measurement sample, the sample is introduced into a glass tube connected to a nitrogen adsorption / desorption measuring device (BELSORP-miniII, manufactured by Nippon Bell Co., Ltd.), and 150 mg of an ATO film sample is heated at 120 degrees for 3 hours in a nitrogen atmosphere The adsorbed water inside and outside the pores was removed. Then, 77K (saturated vapor pressure of the glass tube: 760 mmHg) and cooled to alter the relative pressure (P / P ₀ = adsorption equilibrium pressure / saturated vapor pressure) in the sample tube was measured change in pressure in the glass tube. The sample surface attracts nitrogen molecules with van der Waals force and physically adsorbs them. As a result, a pressure change in the sample tube having a known volume occurs, and the amount of nitrogen physically adsorbed on the sample surface is known.

The measured relative pressure and gas adsorption amount are plotted, and from the slope and intercept of the straight line, V _m (monolayer adsorbed gas amount) and C value (Langmuir theory is expanded to multi-layer adsorption) BET constant) is determined, and the BET specific surface area can be calculated from V _m and the cross-sectional area of nitrogen molecules (nitrogen molecule cross-sectional area: 16.2 ² ).

The BET specific surface area of the ATO porous electrode formed by magnetron sputtering was calculated to be 33.3 m ² / g. In order to make a porous electrode having a large electric capacity by supporting as much organic radical compound as possible, the specific surface area of the porous electrode is preferably about 10 m ² / g or more. Compared to the specific surface area of the sintered ATO porous nanoparticle film (having a particle diameter of several tens of nanometers), the specific surface area is sufficiently large.

  FIG. 9 is a diagram showing a nitrogen adsorption / desorption isotherm of a porous electrode according to an embodiment of the present invention.

FIG. 10 is a diagram showing the pore distribution of a porous electrode according to an embodiment of the present invention, where the horizontal axis is the pore diameter (nm), and the vertical axis is the differential pore volume (V: pore volume, D : Pore diameter, dV / dD) (mm ³ nm ⁻¹ g ⁻¹ ).

  As shown in FIG. 9, the adsorption-side isotherm obtained by sequentially increasing (adsorbing) the adsorption equilibrium pressure is different from the desorption-side isotherm obtained by sequentially decreasing (desorbing) the equilibrium pressure. A line was obtained, showing an isotherm of type IV (according to IUPAC isotherm classification), indicating the presence of mesopores (2 nm to 50 nm).

  As shown in FIG. 10, the porous electrode in the first counter electrode structure described above is not uniform, but has a pore size distribution of 20 nm or less, and includes pores having a diameter of 2 nm to 20 nm.

  The organic radical compounds represented by the chemical formulas (15) to (57) used for increasing the electric capacity of the counter electrode structure cannot be introduced into the micropores (diameter <2 nm) in view of their molecular diameters. Some organic radical compounds tend to aggregate when adsorbed on the surface, and since smooth electron transfer is inhibited by aggregation, it is necessary to adsorb as many compounds as possible in a single molecule state. It is preferable that the pore diameter does not deviate from the meso region, and the result shown in FIG. 10 shows a distribution including pores of 2 nm to 20 nm, which is suitable for adsorption of organic radical compounds.

  Transparency of the ATO porous film in the first counter electrode structure described above was evaluated for transmittance in a wavelength range of 200 to 800 nm by ultraviolet-visible absorption spectrum measurement.

  FIG. 11 is a diagram showing the measurement results of the transmittance of the porous electrode according to the example of the present invention, where the vertical axis represents the transmittance (%) and the horizontal axis represents the wavelength (nm). Here, the transmittance was measured for a counter electrode structure in which a transparent electrode and a porous electrode were formed on a support substrate, and the organic radical compound was not supported on the porous electrode. It is the measured transmittance.

  As is clear from FIG. 11, the curve indicating the change in transmittance is undulated by interference due to the layer structure of the electrode structure including the support substrate, the transparent electrode, and the ATO porous film, but is formed by magnetron sputtering. The filmed ATO film had a very high transmittance, the transmittance at 400 nm was about 60%, the transmittance at 450 nm was about 90%, the transmittance at 600 nm was 96%, and the transmittance at 700 nm was 98%. .

  Tripolar measurement was performed by cyclic voltammetry of the first counter electrode structure 12.

FIG. 12 is a diagram showing the results of cyclic voltammetry of the first counter electrode structure 12 according to the embodiment of the present invention, where the horizontal axis represents the voltage (V) with respect to the reference electrode (Ag / AgNO ₃ ), and the vertical axis. Indicates current (A).

Cyclic voltammetry (CV) uses a general three-electrode system, the above-mentioned first counter electrode structure is a working electrode, the counter electrode is a platinum electrode, and the reference electrode is Ag / AgNO ₃ . The voltage sweep rate in the voltage-current curve was 50 mV / s, and the data of the third cycle in the continuous measurement was adopted. As shown in the voltage-current curve of FIG. 12, a reduction peak was observed at 0.18V and an oxidation peak was observed at 0.35V. Since clear oxidation / reduction peaks are observed in the CV curve, it is possible to reduce power consumption.

  Using the display electrode structure described above and the first counter electrode structure, an electrochromic device having the configuration shown in FIG. 1 is manufactured, and a voltage is applied between the transparent electrodes 2 and 7 to generate voltage-optical characteristics ( The change in absorbance at 635 nm was measured.).

  FIG. 13 is a diagram showing the change in absorbance during color development and decoloration of the display element in the embodiment of the present invention. The horizontal axis represents the voltage applied to the transparent electrodes 2 and 7, that is, the porous electrode ( The voltage applied to the ATO electrode 8 on which 4-Phosphonooxy-TEMPO represented by the chemical formula (22) is supported, and the vertical axis represents the absorbance at 635 nm.

  When a voltage of -1.2 V was applied between the transparent electrodes 2 and 7, a cyan color was developed immediately. The response speed for changing the display from OFF to ON is about 150 ms, which is a sufficiently good speed for practical use. Subsequently, when the voltage was raised to about -1.4 V and then the voltage between the electrodes was reduced to about -1.2 V, the color immediately disappeared and became transparent. The response speed from ON to OFF of color display was about 50 ms, which was a sufficiently good speed for practical use.

  Subsequently, when -1.5 V and 0.5 V were alternately applied 1 million times at 1 Hz between the display electrode structure and the counter electrode structure, the initial state was maintained after 1 million times. It was confirmed that the spectrum shape was hardly changed and the durability was sufficiently excellent in practical use.

  The display device in this example uses a colorless material as the porous electrode constituting the display electrode structure, so that it is surely colorless and transparent when decolored and displays a bright cyan color when colored. I was able to. In addition, since magnetron sputtering is applied as a method for forming the porous electrode constituting the counter electrode structure, it is possible to form a film on a plastic substrate such as a polyethylene naphthalate substrate, and it is practical even in a low temperature environment. It was also confirmed that a display electrode having sufficient color-decoloring characteristics was formed.

(Comparative Example 1)
Using the display electrode structure and the second counter electrode structure described above, an electrochromic device having the configuration shown in FIG. 1 is manufactured, and a voltage is applied between the transparent electrodes 2 and 7 to obtain voltage-optical characteristics (635 nm). As a result of measuring the change in absorbance of the sample, almost no color was observed. This is because the pressure in the vacuum chamber was as low as 0.25 Pa in the manufacturing process of the porous electrode of the second counter electrode structure, so that a very dense antimony-doped tin oxide film was formed in the film formation by magnetron sputtering. This is probably because the contact area with the electrolytic solution was low and the organic EC dye did not sufficiently develop color practically.

(Comparative Example 2)
Using the display electrode structure and the third counter electrode structure described above, an electrochromic device having the configuration shown in FIG. 1 is manufactured, and a voltage is applied between the transparent electrodes 2 and 7 to generate voltage-optical characteristics (635 nm). As a result of measuring the change in absorbance of the sample, almost no color was observed. This is because, in the manufacturing process of the porous electrode of the third counter electrode structure, since there was no oxygen in the vacuum chamber, a crystal structure close to metal was formed in the film formation by magnetron sputtering, and the organic This is probably because the EC dye could not be sufficiently developed.

(Comparative Example 3)
The transparency of the ATO nanoparticle film in the fourth counter electrode structure described above was evaluated for transmittance in a wavelength range of 200 to 800 nm using an ultraviolet-visible absorption spectrometer.

  FIG. 14 is a diagram showing the measurement results of the transmittance of the porous electrode according to the comparative example of the present invention, where the vertical axis represents the transmittance (%) and the horizontal axis represents the wavelength (nm). Here, the transmittance was measured for a counter electrode structure in which a transparent electrode and a porous electrode were formed on a support substrate, and the organic radical compound was not supported on the porous electrode. It is the measured transmittance.

As is clear from FIG. 14, the transmittance of the ATO nanoparticle film formed by the coating method is
It is much lower than the transmittance of the ATO porous electrode in the first counter electrode structure described above (shown in FIG. 11). The transmittance at 400 nm is 0%, the transmittance at 500 nm is 0%, and the transmittance at 600 nm. The transmittance was 1%, and the transmittance at 700 nm was 3%.

  Tripolar measurement was performed by cyclic voltammetry of the fourth counter electrode structure 12.

FIG. 15 is a diagram showing the results of cyclic voltammetry of the fourth counter electrode structure 12 according to a comparative example of the present invention, where the horizontal axis represents the voltage (V) with respect to the reference electrode (Ag / AgNO ₃ ), and the vertical axis. Indicates current (A).

  Cyclic voltammetry was performed in the same manner as in FIG. 12, and as shown in the voltage-current curve of FIG. 12, a reduction peak at 0.10 V and an oxidation peak at 0.35 V were observed.

  Using the above-described fourth display electrode structure and fourth counter electrode structure, an electrochromic device having the structure shown in the figure is produced, and a voltage is applied between the transparent electrodes 2 and 7 to produce voltage-optical characteristics. (Measure the change in absorbance at 635 nm).

  FIG. 16 is a diagram showing a change in absorbance during color development and decoloration of the display element in the comparative example of the present invention, and the horizontal axis represents the voltage applied to the transparent electrodes 2 and 7, that is, the porous electrode ( The voltage applied to the ATO electrode 8 on which 4-Phosphonooxy-TEMPO represented by the chemical formula (22) is supported, and the vertical axis represents the absorbance at 635 nm.

  In this comparative example, when a voltage of -1.2 V was applied between the transparent electrodes 2 and 7, a very thin cyan color was exhibited. The response speed for changing the display from OFF to ON was about 5 s. Further, when the voltage was increased to about -1.4 V and then the interelectrode voltage was decreased to 0 V, the color density was slowly reduced. The response speed for changing the display from ON to OFF was about 8 s.

  In the display device of this comparative example, it was confirmed that even when the voltage was lowered after color development and became 0 V, it was not completely colorless and transparent, and remained unerased. This is due to the low temperature of the heat treatment after applying the predetermined paint by the squeegee method in the manufacturing process of the porous electrode of the fourth display electrode structure, so that the antimony-doped tin oxide nanoparticles are necked (bonded). ) Could not be formed, and polyethylene glycol as a template was not removed. Therefore, it was considered that smooth electron transfer hardly occurred, the color was not developed with sufficient absorbance, and a good response speed could not be obtained.

  As is clear from the above, the use of a colorless and transparent support substrate and porous electrode material, and the use of an organic radical compound makes it extremely excellent in response, sharp colors, and reversible electrochromic. It was possible to realize an electrochromic device capable of stably performing color development and decoloration display using a compound, particularly an electrochromic device suitable for full color display.

  Further, according to the present invention, since the magnetron sputtering method is used as a method for producing the porous electrode, an antimony-doped tin oxide (ATO) porous electrode can be formed under a relatively low temperature condition. ATO porous electrodes can be formed on plastic materials and thin-layer substrates that have lower heat resistance than glass substrates that have been widely used, increasing the degree of freedom in device shape and mode, and flexible display It became possible to fabricate the device.

  In addition, according to the present invention, in the production process of the ATO electrode by the magnetron sputtering method, the pore structure is brought into a good state by performing the pressure under a pressure of 0.5 Pa to 6.0 Pa in the presence of oxygen gas. The color display density on the display electrode side could be sufficiently increased.

  The electrochromic device according to the present invention can be used for display elements and display boards, anti-glare mirrors, dimming elements, optical switches, optical memories and the like used for various applications.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to the above-mentioned embodiment, Various deformation | transformation based on the technical idea of this invention is possible.

  For example, the electrochromic compound supported on the porous electrode can be appropriately selected according to the intended use, and is not limited to the above-described examples. The organic radical compound is not limited to 4-Phosphonooxy-TEMPO represented by the chemical formula (22), and can be arbitrarily changed. Furthermore, the dimension of each illustrated part is not limited to this, It can set suitably according to the objective use.

  Furthermore, the porous electrode is not limited to the tin oxide porous electrode, and may be a porous electrode made of an oxide other than tin oxide, and can be arbitrarily changed as necessary.

    As described above, according to the present invention, a high-performance electrochromic device and a manufacturing method thereof can be provided.

It is sectional drawing explaining schematic structure of an example of the electrochromic apparatus by embodiment of this invention. It is a figure which shows typically the example of schematic structure of a magnetron sputtering apparatus same as the above. It is sectional drawing explaining schematic structure of an example of the electrochromic apparatus which can perform a color display same as the above. It is a figure which shows the X-ray-diffraction pattern of the porous electrode by the Example of this invention. It is a figure which shows the FE-SEM photograph (magnification 150,000) of the surface of a porous electrode same as the above. It is a figure which shows the FE-SEM photograph of the cross section of a porous electrode same as the above. It is a figure which shows the FE-SEM photograph of the cross section of a porous electrode same as the above. It is a figure which shows the FE-SEM photograph of the cross section of the interface of a porous electrode and a board | substrate same as the above. It is a figure which shows the nitrogen adsorption-desorption isotherm of a porous electrode same as the above. It is a figure which shows pore distribution of a porous electrode same as the above. It is a figure which shows the measurement result of the transmittance | permeability of a porous electrode same as the above. It is a figure which shows the result of the cyclic voltammetry of the 1st counter electrode structure 12 same as the above. It is a figure which shows the change of the light absorbency at the time of color development and decoloring of a display element same as the above. It is a figure which shows the measurement result of the transmittance | permeability of the porous electrode by the comparative example of this invention. It is a figure which shows the result of the cyclic voltammetry of the 4th counter electrode structure 12 same as the above. It is a figure which shows the change of the light absorbency at the time of color development and decoloring of a display element same as the above.

Explanation of symbols

1, 1, 1a, 1b, 1c, 6, 6a, 6b, 6c ... support substrate,
2, 2a, 2b, 2c, 7, 7a, 7b, 7c ... transparent electrodes,
3, 3a, 3b, 3c ... organic EC dye, 5, 5a, 5b, 5c ... electrolyte layer,
4, 4a, 4b, 4c, 8, 8a, 8b, 8c ... porous electrode,
10A, 10B, 10C ... electrochromic element structure,
10 ... electrochromic device, 12, 12a, 12b, 12c ... counter electrode structure,
11, 11, 11a, 11b, 11c ... display electrode structure,
13, 13a, 13b, 13c ... organic radical compound 20 ... magnetron sputtering apparatus, 21 ... film formation chamber,
22, 23 ... mass flow controller, 24 ... rotary holder, 25 ... vacuum pump,
26a, 26b ... target, 27 ... substrate, 28 ... diaphragm gauge,
29 ... Ionization gauge, 30a, 30b ... Magnet, 31a, 31b ... Power supply

Claims (19)

A counter electrode structure in which a first transparent electrode is formed on a first support substrate, and a first porous electrode is formed on the first transparent electrode;
A second transparent electrode is formed on the second support substrate, a second porous electrode is formed on the second transparent electrode, and the second porous electrode is colored by an oxidation reaction or a reduction reaction. A display electrode structure carrying a chromic dye; and
An electrolyte layer sandwiched between the first and second transparent electrodes, the first porous electrode being substantially perpendicular to the surface of the first support substrate, and mesoscale pores An electrochromic device, comprising a columnar body having a structure.   The electrochromic device according to claim 1, wherein the first porous electrode is formed of a columnar body having pores of 20 nm or less.   The first porous electrode is made of a semiconductor, and the semiconductor is made of a metal oxide or a metal oxide composite, and the metal is any one of indium, tin, zinc, and aluminum. The electrochromic device described in 1.   The first porous electrode is an RF (high frequency) power source or a DC (direct current) power source, and in addition to the inert gas, oxygen gas is present at a ratio of 10% to 90% in terms of partial pressure, The electrochromic device according to claim 1, wherein the electrochromic device is formed by magnetron sputtering in a vacuum chamber having a total pressure of 0.5 Pa or more and 6.0 Pa or less.   The electrochromic device according to claim 1, wherein the first porous electrode is an antimony-doped tin oxide porous electrode.   The electrochromic device according to claim 5, wherein an organic radical compound having a nitrooxy radical group is supported on the antimony-doped tin oxide porous electrode.   The electrochromic device according to claim 5, wherein the antimony-doped tin oxide porous electrode is formed by magnetron sputtering using a target material mainly composed of tin or tin oxide.   The electrochromic device according to claim 7, wherein the first support substrate is a plastic substrate, and a surface temperature of the plastic substrate at the time of forming the antimony-doped tin oxide porous electrode is 300 ° C or less.   The electrochromic device according to claim 5, wherein the counter electrode structure has a transmittance of 85% or more in a wavelength region of 450 nm or more and 800 nm or less.   A counter electrode structure in which a first transparent electrode is formed on a first support substrate, a first porous electrode is formed on the first transparent electrode, and a second transparent electrode on the second support substrate A display electrode structure in which an electrode is formed, a second porous electrode is formed on the second transparent electrode, and an electrochromic dye that develops color by an oxidation reaction or a reduction reaction is supported on the second porous electrode Is a method of manufacturing an electrochromic device in which an electrolyte layer is sandwiched so that the first and second transparent electrodes are opposed to each other, and the first porous electrode is formed on the first transparent electrode. Forming an electrode by magnetron sputtering, and forming the first porous electrode comprising a columnar body having mesoscale pores substantially perpendicular to the surface of the first support substrate. Chromic clothing The method of production.   The method for manufacturing an electrochromic device according to claim 10, wherein the first porous electrode made of a columnar body having pores of 20 nm or less is formed.   The said 1st porous electrode consists of a semiconductor, This semiconductor is comprised by the composite of the metal oxide or the metal oxide, and the said metal is indium, tin, zinc, or aluminum. A method for producing an electrochromic device as described in 1.   The first porous electrode is an RF (high frequency) power source or a DC (direct current) power source, and in addition to the inert gas, oxygen gas is present at a ratio of 10% to 90% in terms of partial pressure, And the manufacturing method of the electrochromic device of Claim 10 formed by magnetron sputtering in the vacuum chamber whose total pressure is 0.5 Pa or more and 6.0 Pa or less.   The method for manufacturing an electrochromic device according to claim 13, wherein power is directly supplied to the first transparent electrode and a voltage is applied between the first transparent electrode and a target.   The method for manufacturing an electrochromic device according to claim 10, wherein the first porous electrode is an antimony-doped tin oxide porous electrode.   The method for producing an electrochromic device according to claim 15, further comprising a step of supporting an organic radical compound having a nitrooxy radical group on the antimony-doped tin oxide porous electrode.   The method for manufacturing an electrochromic device according to claim 15, wherein the antimony-doped tin oxide porous electrode is formed by magnetron sputtering using a target material mainly composed of tin or tin oxide.   The method of manufacturing an electrochromic device according to claim 17, wherein the first support substrate is a plastic substrate, and a surface temperature of the plastic substrate at the time of forming the antimony-doped tin oxide porous electrode is 300 degrees or less.   The method of manufacturing an electrochromic device according to claim 15, wherein the counter electrode structure has a transmittance of 85% or more in a wavelength region of 450 nm or more and 800 nm or less.