JP5987540B2 - Electrochromic display device and secondary battery integrated solid state element - Google Patents

Description

  The present invention relates to a novel solid-state device having both a secondary battery function and an electrochromic display device function. In particular, the present invention reversibly initiates a redox reaction by applying a voltage, and charges are generated according to the redox reaction. Electrochromic display device / rechargeable battery integrated solid state element in which light transmittance (with color change) changes in conjunction with the accumulation or release of electric charges as well as the storage or release of secondary charge (secondary battery function) It is.

A phenomenon in which a redox reaction occurs reversibly and a color changes reversibly by applying a voltage is called electrochromism. A device using this electrochromism is an electrochromic device. Many studies have been conducted on electrochromic devices to date that applications derived from the characteristics of electrochromism can be realized.
For example, since the colored state and the decolored state change reversibly, an electrochromic device in which the colored state and the transparent state change reversibly can be obtained by using a transparent conductive material as the electrode layer and the counter electrode layer. Is possible. As a result, application to light control glass and ND (dimming) filters can be expected.
As another example, an electrochromic that reversibly changes between a high-reflection state and a low-reflection state by including a metal material that is specularly reflected on one of the electrode layer and the counter electrode layer and using a transparent conductive layer on the other. It is possible to obtain a device. Accordingly, application as an antiglare mirror that suppresses glare can be expected.
As another example, an electrode that includes a material that reflects white in one of the electrode layer and the counter electrode layer and a transparent electroconductive layer on the other is used to reversibly change the high reflection state and the low reflection state. It is possible to obtain a chromic device. As a result, application as a display element of various reflective display displays including electronic paper can be expected.

In addition, the electrochromism phenomenon is characterized in that both the oxidation state and the reduction state can be stably maintained by adjusting conditions such as the structure and composition of the material. According to this feature, since the voltage is applied only when the state is changed, there is an advantage that the energy consumption is small. A display element using such an electrochromism phenomenon can save energy consumption as compared with, for example, a display device that always needs to be driven to emit light using a light emitting source.
Furthermore, the electrochromism phenomenon is characterized in that charges are accumulated in the electrochromic material during the oxidation-reduction reaction. According to this feature, since application as a secondary battery can be expected, secondary batteries using a radical polymer having electrochromic properties have also been developed.

As an electrochromic material, as an organic material, as an electrochromic compound of polymer type, dye type, azobenzene type, anthraquinone type, diarylethene type, dihydroprene type, styryl type, styryl spiropyran type, spirooxazine type, spirothiopyran type Thioindigo, tetrathiafulvalene, terephthalic acid, triphenylmethane, triphenylamine, naphthopyran, viologen, pyrazoline, phenazine, phenylenediamine, phenoxazine, phenothiazine, phthalocyanine, fluoran Low molecular organic electrochromic compounds such as fluoride, fulgide, benzopyran, and metallocene, and conductive polymer compounds such as polyaniline, polythiophene, and PEDOTPS It is. As the inorganic material, inorganic metal oxides such as WO ₃ , Ir (OH) x, MoO ₃ , V ₂ O ₅ , TiO ₂ , NiO and LiNiO ₂ and inorganic complex compounds such as Prussian blue are used.

Since organic materials can be designed with a molecular structure, they have been developed as having the advantage of being able to adjust the color and redox potential.
On the other hand, inorganic materials have problems in color control, but are particularly durable when using a solid electrolytic layer. Utilizing this feature, practical application to a light control glass or ND filter is being studied as an application in which a weak color is an advantage. However, an apparatus using a solid electrolytic layer has a problem that the response speed is slow.

These electrochromic materials are generally sandwiched between two opposing electrodes, and undergo an oxidation-reduction reaction in a configuration in which an electrolyte layer capable of ion conduction is filled between the electrodes. Therefore, the performance of the electrolyte layer (ion conductivity, etc.) affects the response speed and the memory effect of color development. When the electrolyte layer is in the form of a liquid in which the electrolyte is dissolved in a solvent, it is easy to obtain a quick response to some extent. However, improvement by solidification and gelation has been studied in terms of element strength and reliability.
That is, conventionally, since batteries and electrochromic display devices as electrochemical elements have used an electrolytic solution, there are not only the leakage of the electrolytic solution and the drying of the battery due to the volatilization of the solvent, but also the inside of the battery container. Then, due to the bias of the electrolyte, the diaphragm was partially dried, which caused an increase in internal impedance or an internal short circuit.
Especially when an electrochromic device is used for dimming glass or display applications, it is necessary to seal at least one direction with a transparent material such as glass or plastic. This is because it is difficult, and leakage and volatilization of the electrolyte become a larger problem.

As a method for solving the above-described drawbacks, it has been proposed to use a polymer solid electrolyte. Specific examples include a solid solution of a matrix polymer containing an oxyethylene chain or an oxypropylene chain and an inorganic salt, which are completely solid and excellent in processability, but their conductivity is a normal non-aqueous electrolyte. Compared to this, it has a practical problem of being several orders of magnitude lower.
Moreover, in order to improve the electrical conductivity of the polymer solid electrolyte, a method of dissolving an organic electrolyte in a polymer to make it semi-solid (for example, see Patent Document 1), or a liquid monomer to which an electrolyte is added A method for producing a crosslinked polymer containing an electrolyte by polymerization reaction has been proposed, but has not yet reached a practical level.

  As an example using an organic electrochromic compound, Patent Document 2 describes an example in which an organic electrochromic compound is fixed in the vicinity of an electrode to improve the response speed of color development and decoloration. According to the description in Patent Document 2, the time required for color development and decoloration, which has been about several tens of seconds, has been improved to about 1 second for both the color development time from colorless to blue and the color elimination time from blue to colorless. Yes. However, this method does not solve the problem of durability.

  As another example using an organic electrochromic compound, Patent Document 3 discloses an example in which an electronic shuttle material that supports the reaction of an organic electrochromic material is used to improve the response speed of color development and decoloration. Have been described. According to the description in Patent Document 3, the response speed as an antiglare mirror is reduced by 15%. However, it takes about 10 seconds to change the transmittance, and there is still a problem with the response speed.

  On the other hand, as an example using an inorganic electrochromic compound, in an electrochromic device having a structure in which a reduced color layer and an oxidized color layer are disposed opposite to each other with a solid electrolyte layer interposed therebetween, the reduced color layer contains tungsten oxide and titanium oxide. A metal oxide or metal other than nickel oxide, or nickel oxide between the oxidation color development layer and the solid electrolyte layer. An electrochromic device is described in which a transparent intermediate layer composed mainly of a composite of a metal oxide other than a product and a metal is disposed (see Patent Document 4). According to Patent Document 4, it is described that repeating characteristics and responsiveness are improved by forming an intermediate layer, and a color development / erasing drive is possible in a few seconds. However, the structure is complicated, and forming the inorganic chromic compound layer in multiple layers by vacuum film formation is difficult to increase in size and increases the cost.

Furthermore, as a device using an inorganic electrochromic compound, a method of imparting a redox function by changing a metal oxide layer by ultraviolet irradiation has been proposed (see Patent Document 5). In Patent Document 5, a film composed of a metal oxide and an insulator organic compound is spin-formed on an ITO electrode, and is changed to a functional film capable of oxidation and reduction by irradiating with ultraviolet rays. Further, it is described that an electrochromic device in which a nickel oxide layer and an ITO counter electrode are sequentially formed thereon has a color development / decoloration response in several tens of milliseconds. This example is superior in terms of size and cost because an electrolytic layer is not required and a redox functional layer composed of a metal oxide and an insulator organic compound is formed into a spin film.
In addition, according to this technology, it can be applied as a secondary battery. As a semiconductor secondary battery or a quantum battery by Mr. Hatakeyama (see Non-Patent Document 1) of Hiroshima University, Guera Technology (see Non-Patent Document 2) and others. Development is underway, and since it is a high energy density and a solid-state device, it is expected to have advantages such as high safety and excellent environmental resistance.

As described above, Patent Document 5 shows that an electrochromic display device using a redox functional layer is superior in terms of size and cost, whereas according to this technique, a semiconductor secondary battery, Or it is suggested that it is useful as a quantum battery (refer nonpatent literature 1 and nonpatent literature 2).
However, the change in the photoexcitation structure of the composite oxide thin film as described in Non-Patent Document 1 and Non-Patent Document 2 is a new phenomenon, and there is an unclear point about the operating mechanism of the semiconductor secondary battery to which it is applied. Many guidelines for improvement of characteristics were not shown.
The present invention solves the above problems and improves the characteristics of an electrochromic display device / secondary battery integrated solid state device having both a secondary battery function and an electrochromic display device function [for example, charge capacity as a secondary battery It is another object of the present invention to provide an effective technique for improving light transmittance change (color change) as an electrochromic display device.
The solid state element integrated with an electrochromic display device / secondary battery according to the present invention reversibly generates a redox reaction by applying a voltage, and the active layer accumulates or releases charges according to the redox reaction (secondary charge). In addition to the battery function), the light transmittance (color) changes in conjunction with the accumulation or release of the charge (electrochromic display device function), and these characteristics (functions) are improved. .

As a result of detailed analysis, the present inventors have found that a substrate, a first electrode, and an active layer that is composed of a composite of a semiconductor metal oxide and an insulating metal oxide and reversibly causes a redox reaction by voltage application, In the solid-state device configuration including the electron blocking layer and the second electrode, the above problem is solved by providing a porous layer made of a semiconductor metal oxide between the active layer and the first electrode. As a result, the present invention was reached.
That is, the above-described problem is that a substrate, a first electrode, a porous layer made of a semiconductor metal oxide, and a composite of a semiconductor metal oxide and an insulating metal oxide are reversibly oxidized and reduced by voltage application. An active layer, an electron blocking layer, and a second electrode. The active layer accumulates or releases charges by an oxidation-reduction reaction, and the light transmittance changes in conjunction with the accumulation or release of the charges. This is solved by an electrochromic display device / secondary battery integrated solid-state element.

  The electrochromic display device / secondary battery integrated solid element of the present invention includes a substrate, a first electrode, a porous layer made of a semiconductor metal oxide, and a composite of a semiconductor metal oxide and an insulating metal oxide. Comprising an active layer that reversibly causes a redox reaction upon application of a voltage, an electron blocking layer, and a second electrode, and is formed of a semiconductor metal oxide between the first electrode and the active layer. As a result, the area contributing to charge accumulation or emission in the active layer increases, and the charge / discharge capacity as a secondary battery and the change in light transmittance as an electrochromic display device (color) Change) can be improved.

It is sectional drawing which shows schematic structure of the conventional electrochromic display element and a secondary battery element (conventional solid-state element). It is a Si2p spectrum figure [no charge (a), charge state (b)] which shows the partial reduction state of the insulating metal oxide in the active layer observed by X-ray photoelectron spectroscopy analysis. It is sectional drawing which shows schematic structure (a) and the principal part (b) of the electrochromic display apparatus and secondary battery integrated solid element concerning this invention.

  As described above, the electrochromic display device / secondary battery integrated solid element according to the present invention includes a substrate, a first electrode, a porous layer made of a semiconductor metal oxide, a semiconductor metal oxide, and an insulating metal oxide. An active layer that reversibly causes a redox reaction upon application of a voltage, an electron blocking layer, and a second electrode, wherein the active layer accumulates or releases charges by a redox reaction, The light transmittance is changed in conjunction with the accumulation or release of the charge.

The best mode for carrying out the present invention will be described below with reference to the drawings.
FIG. 1 is a cross-sectional view showing a schematic configuration of a conventional electrochromic display element and a secondary battery element (abbreviation: “conventional solid element”).
As shown in FIG. 1, a conventional solid-state element is formed on a substrate 11 in the order of a first electrode 12, an active layer 13, an electron blocking layer 14, and a second electrode 15.
For example, in an electric field sensitive element having a similar structure described in Patent Document 5 (WO2008 / 053561), a light transmitting material made of, for example, indium tin oxide (ITO) is formed on a substrate having a light surface color. Functional layer (corresponding to the first electrode 12), and the first electrode is covered with a translucent layer consisting of a metal oxide and an insulator covering it, and this covering layer has an optical function that exhibits chromism The second electrode layer A [nickel oxide (NiO)] (corresponding to the electron blocking layer 14) and the second electrode layer B [indium oxide. Tin (ITO)] (corresponding to the second electrode 15) is sequentially formed.
In the conventional solid-state device manufactured as described above, when a negative bias is applied to the first electrode side and electrons are injected into the active layer, the active layer is colored along with charge accumulation, and then passes through an external circuit. When the first electrode and the second electrode are connected, the color disappears with the release of electric charge.
However, until now, charge accumulation in the active layer is a phenomenon that occurs at the interface between the first electrode and the active layer, and it has been considered to occur partially near the interface with the first electrode. It is not known how much area actually contributes to charging and what kind of change occurs during charging.

Therefore, the inventors manufactured a conventional solid-state device in accordance with the configuration shown in FIG. 1, applied a negative bias to the first electrode of the solid-state device, and injected electrons from the first electrode to thereby activate the active layer 13. In the active layer, the X-ray photoelectron spectroscopy (XPS) is performed while etching the solid element from the second electrode side by Ar sputtering. The effective active layer region was analyzed by measuring the state.
As a result, a partial reduction state of the insulating metal oxide was observed in a predetermined region from the interface between the first electrode 12 and the active layer 13 toward the upper side of the active layer (the side in contact with the electron blocking layer 14). It was done.
FIG. 2 shows an example of data indicating a partial reduction state when SiO ₂ is used as the insulating metal oxide.
That is, FIG. 2 is a Si2p spectrum diagram showing the partially reduced state of the insulating metal oxide in the active layer observed by X-ray photoelectron spectroscopy [no charge (a), charge state (b)].
The change indicating the partially reduced state observed in the charged state (b) was not observed in the uncharged state (a).
Note that the active layer in FIG. 2 is composed of a mixture (composite oxide) of a semiconductor metal oxide made of tin oxide and an insulating metal oxide made of silicon oxide.

  From the above analysis results, the inventors set the region where the partially reduced state of the insulating metal oxide is observed in the active layer as the effective active layer region. Therefore, by designing a cell structure that increases the active layer area in the active layer, both the charge / discharge capacity as a secondary battery and the light transmittance change (color change) performance as an electrochromic display device are improved. An electrochromic display device / rechargeable battery integrated solid-state device having a structure in which a porous layer made of a semiconductor metal oxide is provided between the first electrode layer and the active layer is obtained. This technology has been completed.

3 (a) and 3 (b), the schematic configuration and the main part of the electrochromic display device / secondary battery integrated solid element of the present invention (hereinafter sometimes referred to as "solid element of the present invention"). FIG.
As shown in FIG. 3A, the solid element of the present invention has an overall configuration in which the first electrode 12, the porous layer 16, the active layer 13, the electron blocking layer 14, and the second electrode 15 are arranged on the substrate 11 in order. Formed.
The porous layer 16 has voids as shown in FIG. 3B, and the voids are shown to be spherical in the figure, but they are not necessarily spherical and may have a random shape. Absent.
That is, the void of the porous layer may have an unspecified shape, and the pore diameter of the void is preferably 20 nm or more and 1 μm or less, and more preferably 50 nm or more and 500 nm or less. In this pore diameter range, it was possible to effectively contribute to an increase in the accumulated charge amount, that is, an improvement in the charge capacity and the transmittance change amount. That is, the pore size values in the range shown here have a correlation with the analysis result of the active layer region effective by X-ray photoelectron spectroscopy, and the introduction of the porous layer according to the present invention (between the first electrode layer and the active layer). It was concluded that a porous layer made of a semiconductor metal oxide was inserted into the effective active layer region. The effective active layer region described above may vary depending on the composition such as the metal material of the active layer and the oxygen deficiency rate, but in this case as well, the effective active layer region is appropriately set by X-ray photoelectron spectroscopy analysis in the same procedure. It can be reflected in the pore size of the porous layer.
The thickness of the porous layer is preferably 20 nm or more, and more preferably 50 nm or more. The upper limit of the thickness is not particularly problematic as long as the porous layer can be produced uniformly and the electron transportability is not significantly reduced. However, when used as an electrochromic display device, the light at the time of color change (decoloration) In consideration of not reducing the transmittance and sufficiently reducing the transmittance change during coloring, 1 μm or less is preferable.

  For the porous layer 16 provided as a constituent layer of the solid element of the present invention, it is possible to use a semiconductor metal oxide such as tin oxide, indium oxide, titanium oxide, zinc oxide, niobium oxide, and tungsten oxide. These may be used alone or as a composite oxide comprising a plurality of them. In particular, at least one semiconductor metal oxide selected from tin oxide or indium oxide, or a composite oxide thereof (for example, ITO) is preferably used.

As a method for forming the porous layer, a method of using nanoparticles, a method of forming a meso or macroporous structure using a surfactant, a method of using a network electrode material, or the like can be used.
In particular, the porous layer is preferably formed using semiconductor metal oxide nanoparticles. By using semiconductor oxide nanoparticles, it is possible to easily form a porous layer simply by applying a dispersion liquid in which nanoparticles are dispersed in a suitable dispersion medium, followed by baking. Such a material comprises at least one semiconductor oxide semiconductor metal oxide selected from the aforementioned tin oxide, indium oxide, titanium oxide, zinc oxide, niobium oxide, and tungsten oxide. Nanometer-sized fine particles are preferably used.
For example, the porous layer can be formed by dispersing the nanometer-sized semiconductor metal oxide fine particles in a solvent to form a dispersion, which is applied and dried on the first electrode. Thereby, a porous layer can be formed easily and reliably.

Hereinafter, each constituent material and formation process in each layer other than the porous layer constituting the electrochromic display device / secondary battery integrated solid element of the present invention (solid element of the present invention) will be described.
〔substrate〕
The substrate 11 is made of a material such as glass, thin film metal, or plastic, and for example, alkali-free glass, borosilicate glass, float glass, soda lime glass, polymer resin, or the like can be used. However, when using a substrate having low heat resistance, it is necessary to set the process temperature to be equal to or lower than the heat resistant temperature of the substrate. When using a metal substrate, it is necessary to form an insulating layer to prevent a short circuit with the first electrode. In the case of using as an electrochromic display device, it is necessary to use a substrate that transmits visible light.

[First electrode]
The first electrode 12 used in the present invention is not particularly limited as long as it is a conductive material when used as a secondary battery, and a known metal, metal oxide, or organic conductive material can be used. . On the other hand, when used as an electrochromic display device, a transparent material can be used.
Examples of the first electrode 11 include indium tin oxide (hereinafter referred to as ITO), fluorine-doped tin oxide (hereinafter referred to as FTO), antimony-doped tin oxide (hereinafter referred to as ATO), and indium / zinc oxide. Metal, niobium / titanium oxide, graphene, and the like, and metals such as CNT, Al, Ti, Ag, Au, and Pt may be used, and these may be used alone or in combination.

  Although there is no restriction | limiting in particular in the thickness of the 1st electrode 12, when using as a secondary battery, a thing with a low specific resistance is preferable from the point of energy density. The film thickness is preferably 5 nm to 1 μm, and more preferably 20 nm to 100 nm. Moreover, when using as an electrochromic display device, it is necessary to use an electrode with high visible light transmittance, and ITO, FTO, ATO, graphene, etc. are preferable in the above.

As the formation process of the first electrode 12, there are known vacuum film formation such as sputtering and vapor deposition, and film formation methods by various printing methods.
In the case of forming by printing, formation by coating pyrolysis of various metal nanoparticle inks or organometallic salt complex inks, formation by a sol-gel method, or the like is possible. Various printing methods such as inkjet method, dispenser method, letterpress, offset, gravure, intaglio, rubber plate, screen printing, dipping method, spray method, wire bar method, spin coating method, roller coating method, blade coating method, etc. Can be used.

[Active layer]
As the active layer 13 constituting the solid state device of the present invention, a thin film made of a composite (composite oxide) in which a semiconductor metal oxide and an insulating metal oxide are mixed can be used.
As the semiconductor metal oxide, tin oxide (tin oxide), titanium oxide (titanium oxide), zinc oxide (zinc oxide) and the like are preferably used. In particular, tin oxide or titanium oxide is preferably used.
On the other hand, as the insulating metal oxide, silicon oxide (silicon oxide) or aluminum oxide (alumina) is preferably used. In particular, silicon oxide is preferably used.

As a process for forming the active layer 13, a nanoparticle ink containing a semiconductor metal oxide and an insulating metal oxide or an organometallic complex ink is used to form by coating and thermal decomposition, or by a sol-gel method. It is possible to apply a method or the like.
When an insulating material such as various silicone compounds is used as the insulating metal oxide, it can be formed by dissolving in a solvent and mixing with a metal material.
When the active layer 13 is formed using a printing process, the same technique as that for the first electrode 12 can be used.
When using the precursor solution for the active layer, for example, a mixed solution of tin 2-ethylhexanoate, toluene, and silicon oil is applied to the surface of the porous layer 16 (for example, spin coating), and after drying, about 500 ° C. The composite oxide thin film which consists of a composite of a tin oxide and a silicon oxide is formed by performing a baking process by.
Next, the composite oxide thin film thus formed is changed into the active layer 13 by performing a structure change process.
As the structure change treatment, a method using ultraviolet irradiation, electron beam irradiation, or the like can be used. As the ultraviolet ray, a high-pressure mercury lamp, a low-pressure mercury lamp, a YAG laser, or the like can be used, and a process with a high irradiation energy density is preferable because the tact time during production can be shortened.
When the active layer (tin oxide and silicon oxide) on the first electrode (for example, ITO) and the porous layer (ITO fine particles) is irradiated with ultraviolet rays by the structure change treatment, the tin oxide (SnO ₂ ) Electrons in the valence band are excited to the conduction band. In the vicinity of the interface with ITO, the electrons pass through the insulator with probability and are temporarily captured by ITO, and the interatomic distance of the site from which the electrons in the valence band have escaped changes. The trapped electrons return to the valence band of tin oxide (SnO ₂ ) again, but the level moves into the band gap. By repeating such an event, a large number of levels are formed in the band gap during ultraviolet irradiation. On the other hand, the electrons to be trapped in these levels are excited by ultraviolet rays and move to ITO, and the levels in the band gap in the absence of the generated electrons remain even after the ultraviolet irradiation ends. The energy of light absorbed by the metal oxide depends on the level in the band gap. In the case of tin oxide (SnO ₂ ), the light transmittance is large when the number of electrons in the band gap is small.
An insulating metal oxide (for example, silicon oxide: SiO ₂ ) plays a role of passing excited electrons. That is, the structure of tin oxide (SnO ₂ ) is changed by being irradiated with ultraviolet rays in a state where silicon oxide (SiO ₂ ) is interposed between ITO and tin oxide (SnO ₂ ).

[Block layer]
The block layer 14 plays a role of preventing unnecessary electron injection from the second electrode 15 to the active layer 13.
As the block layer 14, for example, a thin film made of nickel oxide can be used.
The nickel oxide thin film can be formed by sputtering using NiO as a target.
As the organic material for forming the block layer 14, various p-type semiconductor materials can be used. As an example, a polymer such as polythiophene or a low molecular material such as pentacene can be used.
As a process for forming a block layer made of an organic material, when a polymer material soluble in an organic solvent is used, it can be formed by a printing process. Further, when a low molecular material is used, it can be formed by a process such as vacuum deposition.
In addition, when the electrochromic display device / secondary battery integrated solid element according to the present invention is used as an electrochromic display device, an increase in film thickness causes a decrease in transmittance, so an optimum value needs to be set.

[Second electrode]
As the material used for the second electrode 15, the same materials and processes as those for the first electrode 12 can be applied. That is, when it uses as a secondary battery, if it is an electroconductive material, it will not specifically limit, A well-known metal, a metal oxide, and an organic electroconductive material can be used. On the other hand, when used as an electrochromic display device, the above-mentioned transparent material (for example, ITO) can be used.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated further more concretely, this invention is not limited to these Examples at all.

[Comparative Example 1]
In accordance with the layer configuration shown in the cross-sectional view of FIG.
As the substrate 11, a glass substrate having a length of 40 mm × width of 40 mm and a thickness of 0.7 mm was prepared.
A first electrode layer (first electrode 12) was formed on this glass substrate by depositing an ITO film to a thickness of about 150 nm by a sputtering method through a shadow mask.
Next, a mixed solution of 0.24 g of tin 2-ethylhexanoate, 1.28 ml of toluene, and 1.2 g of silicon oil (TSF433) was prepared. This mixed solution was applied to the surface of the ITO film (first electrode 12) by a spin coat method, dried, and then baked at 500 ° C. for 1 hour to form a mixed film of tin oxide and silicon oxide. . Next, the film subjected to the baking treatment was irradiated with ultraviolet rays. The irradiation intensity was 40 mW / cm ^{2 at} 254 nm and the irradiation time was 5 hours. Thus, the active layer 13 was formed. The film thickness was approximately 400 nm.
After the formation of the active layer 13, a nickel oxide film having a thickness of 140 nm was formed on the active layer 13 using NiO as a target by sputtering to form an electron blocking layer.
Further, a second electrode layer (second electrode 15) was formed on the electron blocking layer 14 by depositing an ITO film with a thickness of about 150 nm by sputtering through a shadow mask.
Thus, a conventional solid element (Comparative Example 1) conforming to the layer configuration shown in FIG. 1 was produced.

The charge / discharge characteristics and the transmittance change were evaluated using the conventional solid-state device (Comparative Example 1) produced above.
When the charge capacity was 0.5 μAhr / cm ² and constant current discharge was measured at 10 μA / cm ² , the final voltage was −0.1 V, the average voltage was −0.9 V, and the discharge capacity was 0.41 μAhr / cm ² . there were.
When the charge capacity was 1.0 μAhr / cm ² and the constant current discharge was measured at 10 μA / cm ^{2, the} average voltage was −0.91 V at a final voltage of −0.1 V, and the discharge capacity was 0.42 μAhr / cm ² . there were.
When the charge capacity was 1.5 μAhr / cm ² and constant current discharge was measured at 10 μA / cm ² , the final voltage was −0.1 V, the average voltage was −0.9 V, and the discharge capacity was 0.41 μAhr / cm ² . there were.
A voltage was applied to the element of Comparative Example 1 at ± 4 V and 1 V / s. The transmittance change at that time (light transmittance change accompanying the color change) varied from 78% to 72% at a wavelength of 555 nm with high visibility.
Table 1 below collectively shows the evaluation results of the charge / discharge characteristics and transmittance change of Comparative Example 1.

[Example 1]
In accordance with the layer structure shown in FIG. 3A, the electrochromic display device / secondary battery integrated element of the present invention (solid element of the present invention) was produced as follows.
As the substrate 11, a glass substrate having a length of 40 mm × width of 40 mm and a thickness of 0.7 mm was prepared.
A first electrode layer (first electrode 12) was formed on this glass substrate by depositing an ITO film to a thickness of about 150 nm by a sputtering method through a shadow mask.
Further, a dispersion liquid in which ITO fine particles having a particle diameter of 80 nm are dispersed in toluene is adjusted to a desired concentration, and this dispersion liquid is applied to the surface of the first electrode 12 by spin coating, and then dried and baked to obtain a thickness of about 80 nm. A porous layer 16 was formed. The size of the voids of the porous layer 16 had a structure with a pore diameter of 50 nm to 200 nm in the plane direction parallel to the first electrode surface.
Next, a mixed solution of 0.24 g of tin 2-ethylhexanoate, 1.28 ml of toluene, and 1.2 g of silicon oil (TSF433) was prepared. This mixed liquid was applied to the surface of the porous layer 16 made of the ITO fine particles by a spin coating method, dried, and then subjected to a baking treatment at 500 ° C. for 1 hour to form a mixed film of tin oxide and silicon oxide. . Next, the film subjected to the baking treatment was irradiated with ultraviolet rays. The irradiation intensity was 40 mW / cm ^{2 at} 254 nm and the irradiation time was 5 hours. Thus, the active layer 13 was formed. The film thickness was approximately 400 nm.
After the formation of the active layer 13, a nickel oxide film having a thickness of 140 nm was formed on the active layer 13 using NiO as a target by sputtering to form an electron blocking layer.
Further, a second electrode layer (second electrode 15) was formed on the electron blocking layer 14 by depositing an ITO film with a thickness of about 150 nm by sputtering through a shadow mask.
This produced the solid element (Example 1) of this invention based on the layer structure shown to Fig.3 (a).

The charge / discharge characteristics and transmittance change were evaluated using the solid element (Example 1) of the present invention produced above.
When the charge capacity was 0.5 μAhr / cm ² and constant current discharge was measured at 10 μA / cm ² , the final voltage was −0.1 V, the average voltage was −0.88 V, and the discharge capacity was 0.43 μAhr / cm ² . there were.
When the charge capacity was set to 1.0 μAhr / cm ² and constant current discharge was measured at 10 μA / cm ^{2, the} average voltage was −0.92 V at a final voltage of −0.1 V, and the discharge capacity was 0.81 μAhr / cm ² . there were.
When the charge capacity was 1.5 μAhr / cm ² and constant current discharge was measured at 10 μA / cm ^{2, the} average voltage was −0.93 V at a final voltage of −0.1 V, and the discharge capacity was 0.92 μAhr / cm ² . there were.
A voltage was applied to the device of Example 1 at ± 4 V and 1 V / s. The transmittance change at that time (light transmittance change accompanying the color change) varied from 76% to 62% at a wavelength of 555 nm with high visibility.
Table 1 below summarizes the evaluation results of charge / discharge characteristics and transmittance change of Example 1.

[Comparative Example 2]
1 except that titanium 2-ethylhexanoate was used instead of tin 2-ethylhexanoate used in Comparative Example 1 (Comparative Example 2) ) Was produced.

The charge / discharge characteristics and the transmittance change were evaluated using the conventional solid-state device (Comparative Example 2) produced above.
When the charge capacity was 0.5 μAhr / cm ² and constant current discharge was measured at 10 μA / cm ^{2, the} average voltage was −1.2 V at a final voltage of −0.1 V, and the discharge capacity was 0.35 μAhr / cm ² . there were.
When the charge capacity was 1.0 μAhr / cm ² and the constant current discharge was measured at 10 μA / cm ^{2, the} average voltage was −1.1 V at a final voltage of −0.1 V, and the discharge capacity was 0.36 μAhr / cm ² . there were.
When the charge capacity was 1.5 μAhr / cm ² and constant current discharge was measured at 10 μA / cm ² , the final voltage was −0.1 V, the average voltage was −1.2 V, and the discharge capacity was 0.37 μAhr / cm ² . there were.
A voltage was applied to the element of Comparative Example 2 at ± 4 V and 1 V / s. The transmittance change at that time (light transmittance change accompanying color change) varied from 81% to 77% at a wavelength of 555 nm with high visibility.
Table 1 below collectively shows the evaluation results of the charge / discharge characteristics and transmittance change of Comparative Example 2.

[Example 2]
The solid element of the present invention conforming to the layer structure shown in FIG. 3 (a) in the same manner as in Example 1 except that titanium 2-ethylhexanoate was used instead of tin 2-ethylhexanoate used in Example 1. Example 2) was prepared.

The charge / discharge characteristics and the transmittance change were evaluated using the solid element (Example 2) of the present invention produced above.
When the charge capacity was 0.5 μAhr / cm ² and constant current discharge was measured at 10 μA / cm ² , the final voltage was −0.1 V, the average voltage was −1.1 V, and the discharge capacity was 0.40 μAhr / cm ² . there were.
When the charge capacity was 1.0 μAhr / cm ² and the constant current discharge was measured at 10 μA / cm ^{2, the} average voltage was −1.31 V at a final voltage of −0.1 V, and the discharge capacity was 0.72 μAhr / cm ² . there were.
When the charge capacity was 1.5 μAhr / cm ² and constant current discharge was measured at 10 μA / cm ^{2, the} average voltage was −1.2 V at a final voltage of −0.1 V, and the discharge capacity was 0.72 μAhr / cm ² . there were.
A voltage was applied to the device of Example 1 at ± 4 V and 1 V / s. The transmittance change at that time (light transmittance change accompanying the color change) varied from 79% to 68% at a wavelength of 555 nm with high visibility.
Table 1 below summarizes the evaluation results of charge / discharge characteristics and transmittance change of Example 2.

  That is, a predetermined region (appropriate range analyzed by X-ray photoelectron spectroscopy analysis) from the interface where the first electrode 12 and the active layer 13 are in contact toward the upper side of the active layer (the side where the electron blocking layer is in contact); In Example 1 and Example 2 of the present invention in which a porous layer made of a semiconductor oxide was provided on about 500 nm), both discharge capacity and transmittance change (according to color change) compared to Comparative Example 1 and Comparative Example 2 It has been clarified that the light transmittance change is improved. That is, it was confirmed that this is an effective technique for improving the charge capacity as a secondary battery and improving the light transmittance change (color change) as an electrochromic display device.

  The electrochromic display device / secondary battery integrated element of the present invention is excellent in terms of upsizing and manufacturing cost because a solid element can be formed regardless of a complicated process, and is also a solid element. Therefore, advantages such as high safety and excellent environmental resistance can be expected. Therefore, it is considered that a useful and effective technique can be provided in the application fields (various secondary batteries, light control glass, ND filter, electronic paper, etc.) as future secondary batteries and electrochromic display devices.

(Reference numerals in FIGS. 1 and 3)
DESCRIPTION OF SYMBOLS 11 Board | substrate 12 1st electrode 13 Active layer 14 Electron block layer 15 2nd electrode 16 Porous layer

Japanese Patent Publication No. 3-73081 Japanese Patent No. 3955641 JP 2009-276800 A Japanese Patent No. 4105537 WO2008 / 053561 publication

Hiroshima University New Technology Briefing 2010 Guera Technology HP http://www.guala-tec.co.jp/

Claims (4)

  An active layer comprising a substrate, a first electrode, a porous layer made of a semiconductor metal oxide, and a composite of a semiconductor metal oxide and an insulating metal oxide, which causes a redox reaction reversibly upon voltage application And an electron blocking layer and a second electrode, wherein the active layer accumulates or releases charges by an oxidation-reduction reaction, and the light transmittance changes in conjunction with the accumulation or release of the charges. Electrochromic display device and secondary battery integrated solid state element.   2. The electrochromic display / secondary battery integrated solid according to claim 1, wherein the porous layer comprises at least one semiconductor metal oxide selected from tin oxide or indium oxide. element. The porous layer, an electrochromic display device, a secondary battery integrated solid state device as claimed in claim 1 or 2, characterized in that it consists of a semiconductor metal oxide nanoparticles. The active layer is a mixture of at least one semiconductor metal oxide selected from tin oxide or titanium oxide and an insulating metal oxide made of silicon oxide. 4. The electrochromic display device / secondary battery integrated solid element according to any one of 3 ).