JP2013015805A - Electrochromic device and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrochromic device superior in productivity including durability, responsiveness, and enlargement.SOLUTION: The electrochromic device includes: an electrode layer 11a; a counter electrode layer 12a disposed so as to face the electrode layer 11a; and an electrochromic layer 13 provided between the electrode layer 11a and the counter electrode layer 12a and in contact with the electrode layer 11a. The electrochromic layer 13 includes a nickel oxide compound layer 13b comprising a compound having a nickel oxide as a main component and a semiconductor particulate-filled layer 13a which is provided between the nickel oxide compound layer 13b and the electrode layer 11a and is filled with semiconductor particulates 13a1.

Description

  The present invention relates to an electrochromic device and a method for manufacturing the same.

  A phenomenon in which a redox reaction occurs reversibly and a color changes reversibly by applying a voltage is called electrochromism (or electrochromic). 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, in order to reversibly change the colored state and the decolored state, an electrochromic device that reversibly changes the colored state and the transparent state is obtained by using a transparent conductive material as the electrode layer and the counter electrode layer. It is possible. Thereby, application to light control glass and ND filter can be expected. As another example, an electrochromic that reversibly changes between a high-reflection state and a low-reflection state by including a mirror-reflecting metal material 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 electrochromic that reversibly changes between a high reflection state and a low reflection state by including a white reflective material in one of the electrode layer and the counter electrode layer and using a transparent conductive layer in the other. It is possible to obtain a 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 (memory effect). According to this feature, it is not necessary to always drive to emit light as in a display device using a light source, and the voltage is applied only when the state is changed. For example, as a display element, energy consumption can be saved as compared with a display device that needs to be driven to emit light at all times using a light source.

  Furthermore, the electrochromism phenomenon is characterized in that charges are accumulated in the electrochromic material during the oxidation-reduction reaction. Since this feature can be expected to be applied as a secondary battery, secondary batteries using an electrochromic radical polymer have also been developed.

As an electrochromic material, organic materials include polymer-based and dye-based electrochromic compounds such as azobenzene, anthraquinone, diarylethene, dihydroprene, styryl, styryl spiropyran, spirooxazine, spirothiopyran. Thioindigo, tetrathiafulvalene, terephthalic acid, triphenylmethane, triphenylamine, naphthopyran, viologen, pyrazoline, phenazine, phenylenediamine, phenoxazine, phenothiazine, phthalocyanine, Low molecular organic electrochromic compounds such as fluoran, fulgide, benzopyran, and metallocene, and conductive polymer compounds such as polyaniline, polythiophene, and PEDOTPSS It is needed. 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.

  Here, the organic material can be developed in various colors depending on its molecular structure, and thus has been developed as a color display device. However, since it is an organic material, there is a problem in durability. 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 light control glass and ND filters is being studied as an application that has an advantage of low color saturation. However, an apparatus using a solid electrolytic layer has a problem that the response speed is slow.

  In addition, these electrochromic materials are generally formed 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. The electrochromic device has a drawback in that the response speed of color development / decoloration is slower than that of a liquid crystal display device because of the principle of performing color development / decoloration utilizing an oxidation-reduction reaction.

  Furthermore, since electrochromic is an electrochemical phenomenon, the performance of the electrolyte layer (such as ionic conductivity) affects the response speed and the memory effect of color development. Conventionally, batteries and electrochromic display devices as electrochemical elements have used an electrolyte solution. Therefore, not only is there leakage of the electrolyte solution and drying of the battery due to volatilization of the solvent. Due to the deviation of the liquid, the diaphragm was partially dried, which caused an increase in internal impedance or an internal short circuit. That is, when the charge layer is in a liquid form in which an electrolyte is dissolved in a solvent, quick response can be easily obtained, but there is a problem in terms of device strength and reliability. 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. It is difficult, and leakage and volatilization of the electrolyte become a larger problem. Therefore, improvement by solidification and gelation of the electrolyte layer has been studied.

  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 for the 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, the problem of durability has not been solved.

  As another example using an organic electrochromic compound, Patent Document 3 describes 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. ing. According to the description in Patent Document 3, the response speed as an antiglare mirror is reduced by 15%, but it takes about 10 seconds to change the transmittance, and there is still a problem with the response speed.

  On the other hand, in the inorganic electrochromic compound, in the electrochromic element having a structure in which the reduction coloring layer and the oxidation coloring layer are arranged to face each other with the solid electrolyte layer sandwiched in Patent Document 4, the reducing coloring layer contains tungsten oxide and titanium oxide. A metal oxide or metal other than nickel oxide, or a nickel oxide between the oxidation color developing layer and the solid electrolyte layer. An electrochromic device in which a transparent intermediate layer composed mainly of a composite of a metal oxide and a metal other than the above is disclosed. According to this document, it is described that the repetition characteristics and responsiveness are improved by forming the intermediate layer, and the color development driving can be performed in a few seconds. However, the structure is complicated and the formation of multiple inorganic chromic compound 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 (for example, see Patent Document 5). In this document, a film composed of a metal oxide and an insulator organic compound is spin-deposited on an ITO electrode, changed to a functional film capable of oxidation / reduction by irradiating with ultraviolet rays, and a nickel oxide layer is further formed thereon. It is described that an electrochromic device in which ITO counter electrodes are sequentially formed responds to color development and decoloration in several tens of milliseconds. In this example, an electrolytic layer is not required, and a redox functional layer composed of a metal oxide and an insulator organic compound is formed by spin film formation, which is excellent in terms of size and cost. However, there is still a problem with productivity, such as requiring ultraviolet irradiation treatment for 1 hour.

  The present invention has been made in view of the above-described problems in the prior art, and an object thereof is to provide an electrochromic device excellent in productivity including durability, responsiveness, and enlargement, and a manufacturing method thereof. .

  The present invention provided to solve the above problems is provided with an electrode layer, a counter electrode layer disposed opposite to the electrode layer, and between the electrode layer and the counter electrode layer and in contact with the electrode layer In the electrochromic device having an electrochromic layer, the electrochromic layer is provided between a nickel oxide compound layer made of a compound containing nickel oxide as a main component, the nickel oxide compound layer, and the electrode layer. An electrochromic device comprising: a semiconductor fine particle filling layer filled with semiconductor fine particles.

  In addition, the present invention provided to solve the above problems includes an electrode layer, a counter electrode layer disposed opposite to the electrode layer, and the electrode layer and the counter electrode layer between and in contact with the electrode layer. An electrochromic device provided with a method of forming an electrochromic device, the step of forming a semiconductor fine particle packed layer filled with semiconductor fine particles by coating on the electrode layer, with respect to the formation of the electrochromic layer; And forming a nickel oxide compound layer made of a compound containing nickel oxide as a main component on the semiconductor fine particle filling layer by a vacuum film forming method.

According to the electrochromic device of the present invention, the semiconductor fine particle filling layer functioning as an electron transporting layer and the nickel oxide compound layer that exhibits an oxidation-reduction reaction by giving and receiving electrons are provided. A reaction is obtained. The size can be increased.
According to the method for manufacturing an electrochromic device of the present invention, the electrochromic device of the present invention can be manufactured by a simple method.

It is sectional drawing which shows the structure in one Embodiment of the electrochromic apparatus which concerns on this invention. It is sectional drawing which shows the structure in other embodiment of the electrochromic apparatus which concerns on this invention. It is a top view which shows the structural example of the electrochromic apparatus in an Example. It is a figure which shows the result of the color development / erasing drive evaluation (1) in Example 1. FIG. It is a figure which shows the result of the color development / erasing drive evaluation (2) in Example 1. FIG. It is a figure which shows the current-voltage characteristic of the light control glass-1, the light control glass-3 (2), and the light control glass-3 (3) in Example 1,3.

The configuration of the electrochromic device according to the present invention will be described below.
FIG. 1 is a cross-sectional view showing the configuration of an electrochromic device according to an embodiment of the present invention.
As shown in FIG. 1, an electrochromic device 10 according to the present invention includes an electrode layer 11a provided on a substrate 11, a counter electrode layer 12a disposed to face the electrode layer 11a, and the electrode layer 11a and the counter electrode layer. In the electrochromic device having the electrochromic layer 13 provided between and in contact with the electrode layer 11a, the electrochromic layer 13 is a nickel oxide compound layer 13b made of a compound mainly composed of nickel oxide. And a semiconductor fine particle filling layer 13a provided between the nickel oxide compound layer 13b and the electrode layer 11a and densely filled with semiconductor fine particles 13a1 so that electrons can be exchanged between them. Have.
The “dense” of the semiconductor fine particle filling layer 13a means that the semiconductor fine particles 13a1 are in contact with each other and electrons can travel from the electrode layer 11a to the nickel oxide compound layer 13b or from the nickel oxide compound layer 13b to the electrode layer 11a. It means that the semiconductor fine particles 13a1 are filled with high density.

  Here, the substrate 11 is made of a material such as highly transparent glass or plastic, and has no absorption in the visible region such as non-alkali glass, borosilicate glass, float glass, soda lime glass, polymer resin, and the like. A transparent material can be used. In particular, a multilayer glass substrate that selectively reflects light in the infrared and ultraviolet regions or has an effect of reducing thermal conductivity may be used. Moreover, you may use plastics, such as PET (polyethylene terephthalate) and a polycarbonate. Among these, it is preferable to use a transparent plastic film for the substrate 11 because a lightweight and flexible display device can be obtained.

  The electrode layer 11a is formed on the substrate 11 before the electrochromic layer 13 is formed.

  The counter electrode layer 12a is applied after the formation of the block layer 14 (the electrochromic layer 13 when the block layer 14 is omitted).

For the electrode layer 11a and the counter electrode layer 12a, the same electrode material can be used, and a support is not necessarily required in a configuration in which strength and sealability are sufficiently maintained. The electrode material is not particularly limited as long as it is a conductive material. Specific examples thereof include metals such as platinum, gold, silver, copper, and aluminum, carbon such as graphite, fullerene, and carbon nanotube. Conductive metal oxides such as carbon compounds, tin-doped indium oxide (hereinafter ITO), fluorine-doped tin oxide (hereinafter FTO), antimony-doped tin oxide (hereinafter ATO), polythiophene, polyaniline, etc. The conductive polymer is mentioned. In addition, when using the electrochromic apparatus 10 as light control glass, since it is necessary to ensure the light transmittance as a whole, the transparent conductive material excellent in transparency and electroconductivity is used. Thereby, the transparency of the glass can be obtained and the coloring contrast can be further increased. As the transparent conductive material, an inorganic material such as ITO, FTO, or ATO can be used. In particular, indium oxide (hereinafter referred to as In oxide) formed by vacuum film formation, tin oxide (hereinafter referred to as In oxide) It is preferably an inorganic material containing any one of Sn oxide and zinc oxide (hereinafter referred to as Zn oxide). In oxides, Sn oxides, and Zn oxides are materials that can be easily formed by sputtering, and are materials that can provide good transparency and electrical conductivity. Particularly preferable materials are InSnO, GaZnO, SnO, In ₂ O ₃ and ZnO. When the electrochromic device 10 is used as a dimming mirror, either the electrode layer 11a or the counter electrode layer 12a may have a reflective function. In that case, a metal layer is included. Examples of the metal layer include Pt, Ag, Au, Cr, rhodium and alloys thereof, or a laminate of these.

  The film thicknesses of the electrode layer 11a and the counter electrode layer 12a are adjusted so as to obtain an electric resistance value necessary for an electrochromic oxidation-reduction reaction. When ITO is used, it is usually in the range of 50 to 500 nm.

  Regarding the formation of the electrode layer 11a, the electrode layer 11a can be appropriately formed on the substrate 11 by a technique such as coating, laminating, vapor deposition, CVD, and bonding depending on the type of electrode material used. Further, regarding the formation of the counter electrode layer 12a, the block layer 14 (when the block layer 14 is omitted) is appropriately selected depending on the type of electrode material used and the type of the block layer 14 (electrochromic layer 13 when the block layer 14 is omitted). Can be formed on the electrochromic layer 13) by techniques such as coating, laminating, vapor deposition, CVD, and bonding.

The counter protection layer 12 is a layer for protecting the surface of the counter electrode layer 12a from the environment.
As a material of the opposing protective layer 12, a general UV curing or thermosetting resin can be used as a transparent resin. Moreover, the preferable film thickness range of the opposing protective layer 12 is 0.5 micrometer-10 micrometers. Moreover, it is also possible to make arbitrary color light control glass (electrochromic device) by coloring the opposing protective layer 12. Further, the counter protective layer 12 can include a substrate similar to the substrate 11.

  When the electrochromic device 10 is used as a dimming mirror, either the substrate 11 or the counter protective layer 12 may be transparent and the other may have a reflective function. Includes metal materials. Examples of the metal material include Pt, Ag, Au, Cr, rhodium and alloys thereof, or those obtained by laminating them.

  As described above, the electrochromic layer 13 is provided between the nickel oxide compound layer 13b made of a compound containing nickel oxide as a main component and between the nickel oxide compound layer 13b and the electrode layer 11a. And a semiconductor fine particle filling layer 13a in which the semiconductor fine particles 13a1 are densely filled so that electrons can be exchanged.

  Among these, the semiconductor fine particle filling layer 13a is an electron transport layer in which the semiconductor fine particles 13a1 are densely filled. The semiconductor fine particle filling layer 13a preferably includes an organic resin (binder resin) 13a2 for binding the semiconductor fine particles 13a1. By including the binder resin 13a2, the interelectrode current that does not contribute to the oxidation-reduction reaction in the electrochromic layer 13 can be reduced, the current efficiency at the time of color development / decoloration is improved, and the reaction speed is improved.

  The material constituting the semiconductor fine particles 13a1 is not particularly limited as long as it is a semiconductor material as an electron transport material, and a known material can be used. Specifically, a single semiconductor such as silicon or germanium, a compound semiconductor typified by a metal chalcogenide, a compound having a perovskite structure, or the like can be given.

  Specifically, titanium oxide, zinc oxide, tin oxide, aluminum oxide (hereinafter referred to as alumina), zirconium oxide, cerium oxide, silicon oxide (hereinafter referred to as silica), yttrium oxide, oxygen boron, magnesium oxide, strontium titanate, potassium titanate, titanium Main components are barium oxide, calcium titanate, calcium oxide, ferrite, hafnium oxide, tungsten oxide, iron oxide, copper oxide, nickel oxide, cobalt oxide, barium oxide, strontium oxide, vanadium oxide, aluminosilicate, calcium phosphate, aluminosilicate, etc. And metal oxides. Moreover, these metal oxides may be used independently and 2 or more types may be mixed and used.

  Among these, titanium oxide, zinc oxide, tin oxide, alumina, zirconium oxide, iron oxide, magnesium oxide, indium oxide, tungsten oxide are considered in view of electrical characteristics such as electrical conductivity and physical characteristics such as optical properties. One kind selected from the above or a mixture thereof is suitable because it can operate with excellent response speed of color development and decoloration. Of these, titanium oxide is most preferred. Titanium oxide fine particles are inexpensive (not used with noble metals) and have excellent redox response in electrochromic devices. The crystal type of these semiconductors is not particularly limited, and may be single crystal, polycrystal, or amorphous.

  Further, the shape of the semiconductor fine particles 13a1 is not particularly limited, but a shape having a large surface area per unit volume (hereinafter referred to as specific surface area) is used. By having a large specific surface area, it is possible to efficiently promote the oxidation-reduction reaction in the nickel oxide compound layer 13b to cause color development and decoloration.

  In addition, although there is no restriction | limiting in particular in the size of the semiconductor fine particle 13a1, 1-100 nm is preferable and, as for the average particle diameter of a primary particle, 5-30 nm is more preferable.

  Moreover, although there is no restriction | limiting in the film thickness of the semiconductor fine particle filling layer 13a, 10 nm-1 micrometer are preferable and 20 nm-700 nm are more preferable.

  There is no restriction | limiting in particular in the preparation methods of the semiconductor fine particle filling layer 13a, The method of forming a thin film in vacuum, such as sputtering, and the wet film-forming method are mentioned. In view of the manufacturing cost and the like, a wet film forming method is particularly preferable, and a method of preparing a dispersion liquid or paste in which a powder or sol of semiconductor fine particles is dispersed and applying it on the electrode layer 11a is preferable.

  When this wet film-forming method is used, the coating method is not particularly limited, and can be performed according to a known method. For example, dip method, spray method, wire bar method, spin coating method, roller coating method, blade coating method, gravure coating method, and wet printing methods such as relief printing, offset, gravure, intaglio printing, rubber printing, screen printing, etc. Can be used.

  In the case of preparing a dispersion using mechanical pulverization or a mill, it is preferable to form at least the semiconductor fine particles 13a1 alone or a mixture of the semiconductor fine particles 13a1 and the resin that becomes the binder resin 13a2 in water or an organic solvent. Alternatively, a nanoparticle in which the binder resin 13a2 is formed in advance on the surface of the semiconductor fine particle 13a1 may be prepared and applied and formed using this particle dispersion paste. In this case, it becomes easy to reliably form the material of the binder resin 13a2 on the surface of the semiconductor fine particles 13a1.

  As the resin used at this time, polymers and copolymers of vinyl compounds such as styrene, vinyl acetate, acrylic acid ester, methacrylic acid ester, silicon resin, phenoxy resin, polysulfone resin, polyvinyl butyral resin, polyvinyl formal resin, Examples include polyester resin, cellulose ester resin, cellulose ether resin, urethane resin, phenol resin, epoxy resin, polycarbonate resin, polyarylate resin, polyamide resin, polyimide resin, and the like.

  The weight ratio of the semiconductor fine particles 13a1 to the binder resin 13a2 (binder resin 13a2 / semiconductor fine particles 13a1) is preferably about 0.5% to 20%. When the amount of the binder resin 13a2 is less than 0.5%, the effect of improving the responsiveness due to the binder resin 13a2 is not sufficient, and when it exceeds 20%, the electrical resistance value of the semiconductor fine particle packed layer 13a becomes high, The color development / decoloration response of the electrochromic layer 13 is reduced.

  As a solvent for dispersing the semiconductor fine particles 13a1, alcohol solvents such as water, methanol, ethanol, isopropyl alcohol, and α-terpineol, ketone solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, ethyl formate, ethyl acetate, or acetic acid Ester solvents such as n-butyl, ether solvents such as diethyl ether, dimethoxyethane, tetrahydrofuran, dioxolane, or dioxane, N, N-dimethylformamide, N, N-dimethylacetamide, or N-methyl-2-pyrrolidone Amido solvents, dichloromethane, chloroform, bromoform, methyl iodide, dichloroethane, trichloroethane, trichloroethylene, chlorobenzene, o-dichlorobenzene, fluorobenzene Halogenated hydrocarbon solvents such as bromobenzene, iodobenzene, or 1-chloronaphthalene, n-pentane, n-hexane, n-octane, 1,5-hexadiene, cyclohexane, methylcyclohexane, cyclohexadiene, benzene, toluene, Examples thereof include hydrocarbon solvents such as o-xylene, m-xylene, p-xylene, ethylbenzene, and cumene. These can be used alone or as a mixed solvent of two or more.

  A dispersion of semiconductor fine particles 13a1 or a paste of semiconductor fine particles 13a1 obtained by a sol-gel method or the like is used in order to prevent re-aggregation of the particles. Acids such as hydrochloric acid, nitric acid and acetic acid, polyoxyethylene (10) octylphenyl ether And the like, chelating agents such as acetylacetone, 2-aminoethanol, and ethylenediamine can be added.

It is also an effective means to add a thickener for the purpose of improving the film formability.
Examples of the thickener added at this time include polymers such as polyethylene glycol and polyvinyl alcohol, and thickeners such as ethyl cellulose.

  The semiconductor fine particles 13a1 are subjected to electronic contact after coating, and firing, microwave irradiation, electron beam irradiation, laser light irradiation are performed in order to improve film strength and adhesion to the substrate (electrode layer 11a). Alternatively, it is preferable to perform a press treatment. These processes may be performed alone or in combination of two or more.

When firing, the range of the firing temperature is not particularly limited, but if the temperature is raised too much, the resistance of the substrate may be increased or the substrate may be melted, so 30 to 700 ° C is preferable, and 100 to 600 ° C is more preferable. Moreover, although there is no restriction | limiting in particular also in baking time, 10 minutes-10 hours are preferable.
After firing, for the purpose of increasing the surface area of the semiconductor fine particles 13a1, for example, chemical plating using an aqueous solution of titanium tetrachloride or a mixed solution with an organic solvent, or electrochemical plating using an aqueous solution of titanium trichloride may be performed. .

  The nickel oxide compound layer 13b is a layer that develops and fades color by an oxidation-reduction reaction, and a material in which the composition ratio of Ni and O is adjusted is used. At this time, if the film is formed so as to contain a large amount of O with respect to NiO, the color density at the time of color development is improved, and high contrast is easily obtained. Furthermore, other metal elements can be used as a material for stabilizing the oxidation-reduction reaction of nickel oxide. The doped metal is preferably Li.

The nickel oxide compound layer 13b can be formed by a particle dispersion paste or a sol-gel method, but the vacuum film formation method is preferable because it is easy to adjust the composition ratio of Ni and O. Particularly preferred is a method in which the partial pressure of O ₂ gas mixed with Ar gas is adjusted, and sputtering film formation is performed with a NiO target.

  Moreover, the preferable film thickness range of the nickel oxide compound layer 13b is 100 nm-500 nm. When the thickness of the nickel oxide compound layer 13b is less than 100 nm, it is difficult to obtain a color-decoloring contrast, and when it exceeds 500 nm, it is easy to color even in a decolored transparent state, and productivity is lowered.

  A preferable film thickness range of the electrochromic layer 13 configured as described above is 0.2 to 5.0 μm. When the film thickness of the electrochromic layer 13 is less than 0.2 μm, it is difficult to obtain the color density, and when it exceeds 5.0 μm, the manufacturing cost increases and the visibility is liable to decrease due to coloring.

  Although the block layer 14 can be omitted, it is useful when the electrochromic layer 13 has a high conductivity. By providing the block layer 14, the interelectrode current that does not contribute to the redox reaction of the electrochromic layer 13 can be reduced, so that the current efficiency during color development is improved and the reaction rate is improved.

As a material of the block layer 14, an n-type semiconductor or an insulator is used. As a specific example, a polymer material is preferable as the organic material, and examples thereof include polyethylene, polyvinyl chloride, polyester, epoxy resin, melamine resin, phenol resin, polyurethane resin, and polyimide resin. As the inorganic material, it is possible to use a material of the aforementioned semiconductor particles 13a1, in terms of insulating _{properties, SiO 2, HfO 2, Ta} 2 O 5, Al 2 O 3, ZrO 2, Si 3 N 4, ZnS And mixtures thereof. Among these, in consideration of physical characteristics of the nickel oxide compound layer 13b, it is preferable to use titanium oxide, which is a metal oxide, as a main component because it has an effect of improving the response speed. At this time, another metal oxide may be mixed with titanium oxide.

  As a method for forming the block layer 14, in the case of the inorganic material, it can be formed by vacuum film formation or particle dispersion paste. On the other hand, the organic material is applied and formed as a solution dissolved in a solvent.

  A preferable film thickness of the block layer 14 varies depending on conditions such as a voltage (drive voltage) applied between the electrode layer 11a and the counter electrode layer 12a, but is approximately 2 nm to 500 nm. Among these, when driving at a low voltage of about 3 to 6 V, 2 nm to 10 nm is preferable. When the film thickness of the block layer 14 is outside this range, an appropriate electrical resistance cannot be obtained between the electrode layer 11a and the counter electrode layer 12a, and it is difficult to obtain the effect of improving the reaction rate (responsiveness).

  In the electrochromic device 10 of the present invention configured as described above, a voltage is applied between the electrode layer 11a and the counter electrode layer 12a, so that the electrochromic layer 13 undergoes an oxidation-reduction reaction by transferring charges (electrons). The color is turned off. That is, the electrochromic layer 13 is colored or uncolored so as to be reversibly changeable. Specifically, when a negative potential is applied to the electrode layer 11a and a positive potential is applied to the counter electrode layer 12a, electrons are supplied from the electrode layer 11a to the nickel oxide compound layer 13b via the semiconductor fine particle filling layer 13a in the electrochromic layer 13. The nickel oxide compound layer 13b is colored black by the oxidation reaction. Further, when a positive potential is applied to the electrode layer 11a and a negative potential is applied to the counter electrode layer 12a, electrons are deprived from the nickel oxide compound layer 13b in the electrochromic layer 13 (the deprived electrons are removed from the semiconductor fine particle filled layer 13a to the electrode layer 11a). The nickel oxide compound layer 13b is transparently decolored by a reduction reaction.

Thereby, the electrochromic device 10 can be operated as a light control glass, a light control mirror or the like or a battery.
For example, in the electrochromic device 10, when both the electrode layer 11a and the counter electrode layer 12a are transparent layers, the transparent state can be reversibly changed by applying a voltage between the electrode layer 11a and the counter electrode layer 12a. Or it can be in a colored state and can be applied to a light control glass, a display device, an ND filter and the like.

  Further, in the electrochromic device 10, when one of the electrode layer 11a and the counter electrode layer 12a is a transparent layer and the other is a layer containing a metal material that is specularly reflected, the electrode layer 11a and the counter electrode layer 12a By applying a voltage between them, it can be reversibly changed to a high reflection state or a low reflection state with respect to incident light, and can be applied to an anti-glare mirror or the like. Alternatively, in the electrochromic device 10, when one of the electrode layer 11 a and the counter electrode layer 12 a is a transparent layer and the other is a layer containing a material that reflects white, between the electrode layer 11 a and the counter electrode layer 12 a Therefore, it is possible to change the incident light to a high reflection state or a low reflection state so as to be reversibly changeable by application of the voltage, and application to a display device or the like is possible.

  As a method of manufacturing the electrochromic device 10 having the above-described configuration, regarding the formation of the electrochromic layer 13, first, a step of forming the semiconductor fine particle filling layer 13a filled with the semiconductor fine particles 13a1 by coating on the electrode layer 11a, And forming a nickel oxide compound layer 13b made of a compound containing nickel oxide as a main component on the semiconductor fine particle filling layer 13a by a vacuum film formation method.

  Thereby, it is possible to manufacture the electrochromic device 10 of the present invention by a simple method. That is, since the semiconductor fine particle filling layer 13a is formed by coating, a thick film layer can be easily obtained, and multilayer formation by vacuum film formation can be reduced, so that the electrochromic device of the present invention can be enlarged. Further, the productivity is excellent. Further, the film state of the nickel oxide compound layer 13b can be easily controlled, and in the electrochromic device 10, the nickel oxide compound layer 13b can be brought into a desired redox state by applying a voltage to the electrochromic layer 13. it can.

  At this time, in the step of forming the semiconductor fine particle filling layer, a dispersion liquid containing semiconductor fine particles 13a1 and an organic resin material is applied onto the electrode layer 11a, and the semiconductor fine particles 13a1 are bonded to each other with an organic resin (binding). It is preferable to form the semiconductor fine particle filling layer 13a by filling the semiconductor fine particles 13a1 in a layered state with the resin 13a2) bound thereto.

Next, FIG. 2 is a cross-sectional view showing a configuration in another embodiment of the electrochromic device according to the present invention.
The electrochromic device 20 according to the present invention includes an electrode layer 11a provided on the substrate 11, a counter electrode layer 12a disposed to face the electrode layer 11a, and the electrode layer 11a and the counter electrode layer 12a. An electrochromic device having an electrochromic layer 23 provided in contact with the electrode layer 11a, wherein the electrochromic layer 23 includes a nickel oxide compound portion made of a compound mainly composed of nickel oxide, and the nickel oxide compound. It includes semiconductor fine particles 13a1 filled in the layer so as to enable electron exchange between the portion and the electrode layer 11a.

  Here, in the electrochromic device 20 of this embodiment, the substrate 11, the electrode layer 11a, the block layer 14, the counter electrode layer 12a, and the counter protective layer 12 are the same as the electrochromic device 10 shown in FIG. Only the chromic layer 23 is different. Specifically, as shown in FIG. 2, the electrochromic layer 23 includes a semiconductor fine particle filled layer 23a filled with the semiconductor fine particles 13a1, an intermediate layer 23b made of a semiconductor material or an insulating material different from the semiconductor fine particles 13a1, and the A nickel oxide compound layer 23c made of a compound containing nickel oxide as a main component is laminated in this order from the electrode layer 11a side.

  In addition, the semiconductor fine particles 13a1 constituting the semiconductor fine particle filling layer 23a and the nickel oxide compound layer 23c constituting compounds mainly composed of nickel oxide are the same as those used in the electrochromic device 10 shown in FIG. Therefore, it differs from the electrochromic device 10 shown in FIG. 1 in the layer structure of the electrochromic layer 23 and the constituent material of the intermediate layer 23b.

The intermediate layer 23b is a thin film made of a semiconductor material or an insulating material different from the semiconductor fine particles 13a1. By providing the intermediate layer 23b, the interelectrode current that does not contribute to the oxidation-reduction reaction in the electrochromic layer 23 can be reduced, the current efficiency at the time of color development / decoloration is improved, and the reaction speed is improved.
In addition, it is preferable to make the film thickness of the intermediate | middle layer 23b thin to such an extent that the electron transfer between the nickel oxide compound layer 23c and the electrode layer 11a is not prevented.

Further, as the material constituting the intermediate layer 23b, a compound made of a semiconductor material or an insulating material different from the material constituting the semiconductor fine particles 13a1 is used, and an organic material or an inorganic material may be used. Such a material is not particularly limited, but a transparent material having excellent heat resistance is preferable from the viewpoint of device manufacturing process and device durability. As a specific material, an organic material is preferably a polymer material from the above viewpoint, and examples thereof include polyethylene, polyvinyl chloride, polyester, epoxy resin, melamine resin, phenol resin, polyurethane resin, and polyimide resin. Although Examples of the inorganic material may be a material of the aforementioned semiconductor particles 13a1, in terms of insulating _{properties, SiO 2, HfO 2, Ta} 2 O 5, Al 2 O 3, ZrO 2, Si 3 N 4, ZnS Or a mixture thereof.

  In addition, the intermediate layer 23b can be formed by a vacuum film forming method, but it is preferably formed by coating from the viewpoint of productivity. For example, when the intermediate layer material is an organic material, it is formed by coating using a solution dissolved in a solvent.

In the electrochromic device 20 of the present invention configured as described above, a voltage is applied between the electrode layer 11a and the counter electrode layer 12a, so that the electrochromic layer 23 undergoes an oxidation-reduction reaction by transferring charges (electrons). The color is turned off. Specifically, when a negative potential is applied to the electrode layer 11a and a positive potential is applied to the counter electrode layer 12a, electrons are supplied from the electrode layer 11a to the nickel oxide compound layer 23c via the semiconductor fine particle filling layer 23a in the electrochromic layer 23. The nickel oxide compound layer 23c is colored black by the oxidation reaction. When a positive potential is applied to the electrode layer 11a and a negative potential is applied to the counter electrode layer 12a, electrons are deprived from the nickel oxide compound layer 23c in the electrochromic layer 23 (the deprived electrons are depleted from the semiconductor fine particle filled layer 23a to the electrode layer 11a). The nickel oxide compound layer 23c is transparently decolored by the reduction reaction.
Thereby, the electrochromic device 20 can be operated as a light control glass or a battery.

  As a method of manufacturing the electrochromic device 20 having the above configuration, with respect to the formation of the electrochromic layer 23, first, a step of forming the semiconductor fine particle filled layer 23a filled with the semiconductor fine particles 13a1 by coating on the electrode layer 11a, and filling the semiconductor fine particles A step of forming an intermediate layer 23b made of a semiconductor material or an insulating material different from the semiconductor fine particles 13a1 on the layer 23a by a coating or vacuum film forming method, and nickel oxide as a main component on the intermediate layer 23b by a vacuum film forming method. And a step of forming the nickel oxide compound layer 23c made of the compound to be formed.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, embodiment of this invention is not limited to these Examples.

Example 1
[Production of light control glass device]
<Formation of electrode layer / electrochromic layer / counter electrode layer>
A glass substrate having a size of 40 mm × 40 mm and a thickness of 0.7 mm is prepared as the substrate 11, and an electrode layer 11 a is formed on the glass substrate by depositing an ITO film to a thickness of about 100 nm by a sputtering method. Formed.
Next, a titanium oxide nanoparticle dispersion (trade name: SP210, manufactured by Showa Titanium Co., Ltd., average particle size: about 20 nm) is applied to the surface of the ITO film by a spin coating method and annealed at 120 ° C. for 15 minutes. A semiconductor fine particle packed layer 13a made of a titanium oxide particle film having a thickness of about 1.0 μm was formed. The titanium oxide nanoparticle dispersion was mixed with an organic polymer (mixed product of about 1% hydrophilic organic polymer) as a binder so that the weight ratio of organic polymer / titanium oxide was 5 wt%.
Subsequently, using NiO as a target and a sputtering gas in which the O ₂ partial pressure is 12% with respect to Ar, a compound layer (made of nickel oxide) is formed on the semiconductor fine particle packed layer 13a (titanium oxide particle film) by sputtering. A nickel oxide compound layer 13b) was formed. Furthermore, the counter electrode layer 12a was formed by forming an ITO film on it to a thickness of about 100 nm by sputtering.
The electrochromic light control glass-1 which is the electrochromic device 10 (however, the block layer 14 and the opposing protective layer 12 are omitted) having the configuration shown in FIG. FIG. 3 shows a configuration of the manufactured sample as viewed from above. Here, the electrochromic reaction region (the region where the electrode layer 11a formation region, the electrochromic layer 13 formation region, and the counter electrode layer 12a formation region overlap) is 25 mm × 10 mm.

[Color-erasing drive evaluation (1)]
The electrochromic reaction region of the produced light control glass-1 was in a black colored state.
First, a positive electrode was connected to the electrode layer 11a of this light control glass, a negative electrode was connected to the counter electrode layer 12a, and a voltage of +7 V was applied for 5 seconds. As a result, the electrochromic reaction region disappeared transparently.
Next, when a negative electrode was connected to the electrode layer 11a and a positive electrode was connected to the counter electrode layer 12a, and a voltage of -7V was applied for 5 seconds, it returned to a black colored state. Further, even after applying a voltage of −7 V for 5 seconds and then leaving it for 60 minutes without applying a voltage, the colored state was maintained, and thus it was confirmed that the memory property was excellent. In the memory, an open circuit configuration is used between the electrode layer 11a and the counter electrode layer 12a.
FIG. 4 shows the transmission spectrum in the decolored state and the transmission state in the colored state of the light control glass 1 at this time. The transmittance at a wavelength of 550 nm with high visibility changed from 54% (decolored state) to 33% (colored state). Thus, it was confirmed that the sample of the electrochromic device 10 of the present invention exhibits a transparent-colored electrochromic.

[Color-erasing drive evaluation (2)]
A constant voltage was applied to the produced light control glass-1, and the decoloring response speed was measured. Here, + 4V, + 5V, + 7V, and + 10V are applied with the electrode layer 11a as the positive electrode and the counter electrode layer 12a as the negative electrode, and −4V is applied with the electrode layer 11a as the negative electrode and the counter electrode layer 12a as the positive electrode. Then, the change in transmittance at a wavelength of 550 nm due to voltage application time was measured. The result is shown in FIG.
It was confirmed that the sample of the present invention had a decoloring response in 18 seconds under a +4 V application condition (13 seconds under a +5 V application condition) and 1 second under a +10 V application condition (FIG. 5A). On the other hand, it was confirmed that a coloring response was obtained in 5 seconds under a -4V application condition (FIG. 5B).

(Example 2)
In Example 1, the nickel oxide compound layer 13b was formed by using NiO as a target and LiNiO (Li: 15 atm%), and electrochromic light control glass-2 was produced in the same manner as in Example 1.

The electrochromic reaction region of the produced light control glass-2 was in a black colored state. When a positive electrode was connected to the electrode layer 11a of the light control glass-2 and a negative electrode was connected to the counter electrode layer 12a, and a voltage of +10 V was applied for 3 seconds, the electrochromic reaction region disappeared transparently.
Next, the negative electrode was connected to the electrode layer 11a, the positive electrode was connected to the counter electrode layer 12a, and a voltage of −10 V was applied for 3 seconds. Further, even after applying a voltage of −10 V for 3 seconds and then leaving it for 60 minutes without applying a voltage, the colored state was maintained, and thus it was confirmed that the memory property was excellent. In the memory, an open circuit configuration is used between the electrode layer 11a and the counter electrode layer 12a.
At this time, the transmittance of the light control glass-2 at a wavelength of 550 nm was changed from 52% (decolored state) to 23% (colored state). It was confirmed that the sample of the electrochromic device 10 of the present invention exhibits a transparent-colored electrochromic.

(Example 3)
(Test Example 3-1)
In Example 1, a TiO ₂ film having a thickness of about 20 nm is formed by sputtering on the nickel oxide compound layer 13b (NiO film) between the electrochromic layer 13 and the counter electrode layer 12a. Thus, the block layer 14 was formed, and electrochromic light control glass-3 (1) was produced in the same manner as in Example 1 except that.

The electrochromic reaction region of the produced light control glass-3 (1) was in a black colored state. When a positive electrode was connected to the electrode layer 11a of the light control glass-3 (1) and a negative electrode was connected to the counter electrode layer 12a, and a voltage of +7 V was applied for 2 seconds, the electrochromic reaction region was transparently decolored.
Next, when a negative electrode was connected to the electrode layer 11a and a positive electrode was connected to the counter electrode layer 12a, and a voltage of −7 V was applied for 2 seconds, the state returned to a black colored state. Further, even after applying a voltage of −7 V for 2 seconds and then leaving it for 60 minutes without applying a voltage, the colored state was maintained, and thus it was confirmed that the memory property was excellent. In the memory, an open circuit configuration is used between the electrode layer 11a and the counter electrode layer 12a.
At this time, the transmittance of the light control glass-3 (1) at a wavelength of 550 nm was changed from 58% (decolored state) to 30% (colored state). It was confirmed that the sample of the electrochromic device 10 of the present invention exhibits a transparent-colored electrochromic.

(Test Example 3-2)
In Test Example 3-1, the thickness of the block layer 14 (TiO ₂ film) was 10 nm, and electrochromic light control glass-3 (2) was prepared in the same manner as in Test Example 3-1.

The electrochromic reaction region of the produced light control glass-3 (2) was in a black colored state. When a positive electrode was connected to the electrode layer 11a of the light control glass-3 (2) and a negative electrode was connected to the counter electrode layer 12a, and a voltage of +7 V was applied for 2 seconds, the electrochromic reaction region was decolorized transparently.
Next, the negative electrode was connected to the electrode layer 11a, the positive electrode was connected to the counter electrode layer 12a, and a voltage of −4 V was applied for 4 seconds. Further, even after applying a voltage of −4 V for 4 seconds and leaving it for 60 minutes without applying a voltage, the colored state was maintained, and thus it was confirmed that the memory property was excellent. In the memory, an open circuit configuration is used between the electrode layer 11a and the counter electrode layer 12a.
At this time, the transmittance of the light control glass-3 (2) at a wavelength of 550 nm was changed from 57% (decolored state) to 35% (colored state). It was confirmed that the sample of the electrochromic device 10 of the present invention exhibits a transparent-colored electrochromic.

(Test Example 3-3)
In Test Example 3-1, the thickness of the block layer 14 (TiO ₂ film) was set to 2 nm. Otherwise, Electrochromic light control glass-3 (3) was produced in the same manner as in Test Example 3-1.

The electrochromic reaction region of the produced light control glass-3 (3) was in a black colored state. When a positive electrode was connected to the electrode layer 11a of the light control glass-3 (3) and a negative electrode was connected to the counter electrode layer 12a, and a voltage of +7 V was applied for 2 seconds, the electrochromic reaction region was transparently erased.
Next, when a negative electrode was connected to the electrode layer 11a and a positive electrode was connected to the counter electrode layer 12a, and a voltage of −4 V was applied for 3 seconds, the state returned to a black colored state. Further, even after applying a voltage of −4 V for 3 seconds and then leaving it for 60 minutes without applying a voltage, the colored state was maintained, and thus it was confirmed that the memory property was excellent. In the memory, an open circuit configuration is used between the electrode layer 11a and the counter electrode layer 12a.
At this time, the transmittance of the light control glass-3 (3) at a wavelength of 550 nm was changed from 57% (decolored state) to 38% (colored state). It was confirmed that the sample of the electrochromic device 10 of the present invention exhibits a transparent-colored electrochromic.

(Test Example 3-4)
In Test Example 3-1, the thickness of the block layer 14 (TiO ₂ film) was 1 nm, and electrochromic light control glass-3 (4) was prepared in the same manner as in Test Example 3-1.

The electrochromic reaction region of the produced light control glass-3 (4) was in a black colored state. When a positive electrode was connected to the electrode layer 11a of the light control glass-3 (4) and a negative electrode was connected to the counter electrode layer 12a, and a voltage of +7 V was applied for 2 seconds, the electrochromic reaction region was transparently decolored.
Next, when the negative electrode was connected to the electrode layer 11a and the positive electrode was connected to the counter electrode layer 12a, and a voltage of -4V was applied, it returned to the black colored state in 5 seconds, which was longer than Test Example 3-3. . Further, even after applying a voltage of −4 V for 5 seconds and then leaving it for 60 minutes without applying a voltage, the colored state was maintained, and thus it was confirmed that the memory property was excellent. In the memory, an open circuit configuration is used between the electrode layer 11a and the counter electrode layer 12a.
At this time, the transmittance of the light control glass-3 (4) at a wavelength of 550 nm was changed from 59% (decolored state) to 38% (colored state). It was confirmed that the sample of the electrochromic device 10 of the present invention exhibits a transparent-colored electrochromic.

FIG. 6 shows the current-voltage characteristics (CV characteristics) of the light control glass-1, light control glass-3 (2), and light control glass-3 (3).
As shown in FIG. 6, in the light control glass-3 (2) (block layer 14 thickness 10 nm) and the light control glass-3 (3) (block layer 14 thickness 2 nm), a negative bias is applied, that is, during coloring. It turned out that the electric current value is suppressed rather than the light control glass-1 (without the block layer 14). That is, by inserting the block layer 14, the current component that does not contribute to the oxidation-reduction reaction during coloring is suppressed, and efficient driving can be realized. As a result, the responsiveness during coloring is improved. In addition, the decoloring reaction was not adversely affected by the insertion of the block layer 14.

(Comparative Example 1)
In Example 1, instead of the semiconductor fine particle filling layer 13a (titanium oxide particle film), a TiO ₂ film is formed on the electrode layer 11a (ITO electrode layer) by sputtering so as to have a thickness of about 200 nm. Otherwise, Comparative Sample-1 for comparison was produced in the same manner as in Example 1.

  The electrochromic reaction region of the produced comparative sample-1 was in a black colored state. However, a positive electrode was connected to the electrode layer 11a of this comparative sample-1 and a negative electrode was connected to the counter electrode layer 12a, and a voltage of +10 V was applied for 20 seconds, but the electrochromic reaction region did not become transparent.

  As described above, according to the electrochromic device of the present invention, a result of a color development / decoloration response at a high speed was obtained. This is considered to be due to the improvement in the redox efficiency of the nickel oxide compound layer 13b due to the surface sensitization of the semiconductor fine particles 13a1.

Although the present invention has been described with the embodiments shown in the drawings, the present invention is not limited to the embodiments shown in the drawings, and other embodiments, additions, modifications, deletions, etc. Can be changed within the range that can be conceived, and any embodiment is included in the scope of the present invention as long as the effects and advantages of the present invention are exhibited.
For example, in the present embodiment, the semiconductor fine particle filling layers 13a and 23a and the nickel oxide compound layers 13b and 23c are configured as separate layers, but these may be formed as one layer. That is, the electrochromic layer may be filled with the semiconductor fine particles 13a1 carrying a compound containing nickel oxide as a main component.

10, 20 Electrochromic device 11 Substrate 11a Electrode layer 12 Counter protective layer 12a Counter electrode layer 12a
13, 23 Electrochromic layer 13a, 23a Semiconductor fine particle filling layer 13a1 Semiconductor fine particle 13a2 Binder resin 13b, 23c Nickel oxide compound layer 14 Block layer 23b Intermediate layer

Japanese Patent Publication No. 3-73081 Japanese Patent No. 3955641 JP 2009-276800 A Japanese Patent No. 4105537 International Publication No. 2008/053561

Claims (11)

In an electrochromic device comprising: an electrode layer; a counter electrode layer disposed opposite to the electrode layer; and an electrochromic layer provided between and in contact with the electrode layer.
The electrochromic layer includes a nickel oxide compound layer made of a compound containing nickel oxide as a main component, a semiconductor fine particle filled layer provided between the nickel oxide compound layer and the electrode layer, and filled with semiconductor fine particles. And an electrochromic device.   The electrochromic device according to claim 1, wherein the semiconductor fine particle packed layer includes a binder resin that binds the semiconductor fine particles.   The electrochromic device according to claim 1, wherein the semiconductor fine particles are made of a metal oxide semiconductor material.   The electrochromic device according to any one of claims 1 to 3, further comprising a block layer containing an n-type semiconductor material or an insulating material between the electrochromic layer and the counter electrode layer.   The electrochromic device according to claim 4, wherein the block layer is made of titanium oxide.   6. The electrochromic device according to claim 4, wherein the block layer has a thickness of 2 nm or more and 10 nm or less.   The electrochromic layer is in a colored state or a non-colored state so as to be reversibly changeable by application of a voltage between the electrode layer and the counter electrode layer. Electrochromic device.   The electrode layer and the counter electrode layer are both transparent, and are in a transparent state or a colored state that can be reversibly changed by applying a voltage between the electrode layer and the counter electrode layer. The electrochromic device described.   Either one of the electrode layer and the counter electrode layer is transparent, and the other includes a metal material that reflects specularly or a material that reflects white, and is reversible when a voltage is applied between the electrode layer and the counter electrode layer. The electrochromic device according to claim 7, wherein the electrochromic device is in a high reflection state or a low reflection state with respect to incident light so as to be changeable. A method for manufacturing an electrochromic device, comprising: an electrode layer; a counter electrode layer disposed opposite to the electrode layer; and an electrochromic layer provided between and in contact with the electrode layer Because
Regarding the formation of the electrochromic layer, a step of forming a semiconductor fine particle filled layer filled with semiconductor fine particles by coating on the electrode layer, and a main component of nickel oxide by a vacuum film forming method on the semiconductor fine particle filled layer And a step of forming a nickel oxide compound layer comprising the compound to be produced. The step of forming the semiconductor fine particle filling layer is performed by applying a dispersion liquid containing semiconductor fine particles and an organic resin material on the electrode layer, and binding the semiconductor fine particles with an organic resin. The method for producing an electrochromic device according to claim 10, wherein a layer of semiconductor fine particles is formed by filling the layers in a layer form.