Crystal oriented film, structure, and production method for crystal oriented film

Abstract

To provide a novel crystal oriented film that contains tungsten.SOLUTION: A crystal oriented film contains a hexagonal ring structure consisting of a tungsten-oxygen octahedral block and a one-dimensional tunnel structure. The one-dimensional tunnel structure is oriented perpendicular to the film plane of the crystal oriented film.SELECTED DRAWING: Figure 13

Description

[Technical Field]

[0001] The present invention relates to a crystal orientation film, a structure, and a method for manufacturing a crystal orientation film. [Background technology]

[0002] Patent Document 1 discloses an infrared-shielding material microparticle dispersion in which infrared-shielding material microparticles are dispersed in a medium, the infrared-shielding material microparticles containing tungsten oxide microparticles and / or composite tungsten oxide microparticles, and the particle diameter of the infrared-shielding material microparticles is 1 nm or more and 800 nm or less.

[0003] Patent Document 2 discloses a laminated structure for shading solar radiation, which is formed by sandwiching an intermediate layer containing fine particles having a solar radiation shielding function between two laminated plates selected from glass plates, plastics, and plastics containing fine particles having a solar radiation shielding function, and which is characterized in that the fine particles having a solar radiation shielding function are composed of tungsten oxide fine particles and / or composite tungsten oxide fine particles.

[0004] Patent Document 3 describes a tungsten oxide or / and composite tungsten oxide film having a maximum transmittance of 10% or more and less than 92% in the wavelength range of 400 nm or more and 780 nm or less, and a film surface resistance (sheet resistance) of 1.0 × 10 10 A transparent conductive film characterized by a resistivity of Ω / □ or less is disclosed. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2005 / 037932 [Patent Document 2] International Publication No. 2005 / 087680 [Patent Document 3] Japanese Patent Application Laid-Open No. 2006-96656 [Non-patent literature]

[0006] [Non-Patent Document 1] ACS Nano 2020,14,15216 Summary of the Invention [Problem to be solved by the invention]

[0007] As disclosed in Patent Documents 1 to 3, tungsten oxides and composite tungsten oxides are known to function as infrared shielding materials, transparent conductive films, and the like, and can be used for a variety of applications.

[0008] Furthermore, new films using tungsten-containing oxides have been desired in order to realize new functions and to be applied to new applications.

[0009] Therefore, one aspect of the present invention aims to provide a new crystal orientation film containing tungsten. [Means for solving the problem]

[0010] In one aspect of the present invention, there is provided a crystal orientation film, It contains a six-membered ring structure consisting of tungsten-oxygen octahedral blocks and a one-dimensional tunnel structure. A crystal orientation film is provided in which the one-dimensional tunnel structure is oriented in a direction perpendicular to the film surface of the crystal orientation film. [Effects of the Invention]

[0011] In one aspect of the present invention, a new crystallographically oriented film containing tungsten can be provided. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is an explanatory diagram of the crystal structure of hexagonal tungsten bronze, which is an example of the crystal orientation film of this embodiment. [Figure 2]FIG. 2 is an explanatory diagram of the crystal structure of orthorhombic (pseudo-hexagonal) tungsten bronze, which is an example of the crystal orientation film of this embodiment. [Figure 3] FIG. 3 is an explanatory diagram of the crystal structure of monoclinic (pseudo-orthorhombic) tungsten bronze, which is an example of the crystal orientation film of this embodiment. [Figure 4] FIG. 4 is an explanatory diagram of the crystal structure of a layered compound made of Cs6W11O36 and a molecular film made of Cs4W11O36. [Figure 5] FIG. 5 is an explanatory diagram of the crystal structure of an example of the crystal orientation film of this embodiment. [Figure 6] FIG. 6 is a schematic cross-sectional view of an example of the crystal orientation film of this embodiment. [Figure 7] FIG. 7 is a schematic cross-sectional view of an example of the structure of this embodiment. [Figure 8] FIG. 8 is a schematic cross-sectional view of an example of the structure of this embodiment. [Figure 9] FIG. 9 is a schematic cross-sectional view of an example of the structure of this embodiment. [Figure 10] FIG. 10 is a schematic cross-sectional view of an example of the structure of this embodiment. [Figure 11] FIG. 11 is a schematic cross-sectional view of an example of the structure of this embodiment. [Figure 12] FIG. 12 shows an X-ray diffraction pattern of the crystalline orientation film according to Example 1. As shown in FIG. [Figure 13] FIG. 13 is a transmission electron microscope image of the oriented crystal film according to Example 1. As shown in FIG. [Figure 14] FIG. 14 is a transmission electron microscope image of the oriented crystal film according to Example 2. [Figure 15] FIG. 15 is a transmission electron microscope image of the oriented crystal material according to Comparative Example 1. [Figure 16] FIG. 16 shows the X-ray diffraction pattern of the crystalline orientation film according to Reference Example 1. As shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. However, the present invention is not limited to the following embodiments, and various modifications and substitutions can be made to the following embodiments without departing from the scope of the present invention. [Crystalline Orientation Film] (1) Crystal structure of crystal-oriented films The crystalline oriented film of this embodiment preferably includes a six-membered ring structure made of tungsten-oxygen octahedral blocks and a one-dimensional tunnel structure. The crystalline oriented film of this embodiment can also be composed of only the six-membered ring structure made of tungsten-oxygen octahedral blocks and the one-dimensional tunnel structure, but this does not exclude the inclusion of unavoidable impurities mixed in during the manufacturing process, etc.

[0014] The six-membered ring structure and one-dimensional tunnel structure contained in the crystalline orientation film of this embodiment will be described with reference to FIG. 1, which is an example of a schematic plan view.

[0015] 1 shows the crystal structure of hexagonal tungsten bronze having a plurality of tungsten-oxygen octahedral blocks 11 formed of WO units. The crystal oriented film of this embodiment may contain, for example, such hexagonal tungsten bronze. The tungsten-oxygen octahedral blocks 11 have a structure in which oxygen is located at the vertices of the octahedron and tungsten is located at the center of the octahedron.

[0016] The crystal oriented film of this embodiment has a six-membered ring structure 11A formed by an assembly of six tungsten-oxygen octahedral blocks 11, similar to the hexagonal tungsten bronze shown in Figure 1. The six-membered ring structure 11A can be the same as or similar to the structure of hexagonal tungsten bronze. The hexagonal tungsten bronze can have a one-dimensional tunnel structure 12 at the center of the six-membered ring structure 11A along the direction perpendicular to the plane of the paper in Figure 1 (the c-axis direction).

[0017] The crystalline oriented film of this embodiment may also contain a composite tungsten oxide. When the crystalline oriented film of this embodiment contains a composite tungsten oxide, the composite tungsten oxide has a structure including a six-membered ring structure 11A formed by an assembly of six tungsten-oxygen octahedral blocks 11 and a one-dimensional tunnel structure 12 that is a hexagonal void. The composite tungsten oxide can have a structure in which a single unit is formed by the six-membered ring structure 11A and M13, an element or atomic group contained in the composite tungsten oxide, which is arranged in the one-dimensional tunnel structure 12, and many such units are assembled. Elements and atomic groups that can be suitably used as M13, the element or atomic group contained in the composite tungsten oxide, will be described later. Note that part or all of M13 may be a void.

[0018] The crystal oriented film of this embodiment can have the same hexagonal crystal structure as hexagonal tungsten bronze, as well as the orthorhombic crystal structure shown in FIG. 2 or the monoclinic crystal structure shown in FIG. 3. The orthorhombic crystal structure shown in FIG. 2 is almost the same as the hexagonal tungsten bronze having the hexagonal crystal structure shown in FIG. 1, but is slightly stretched in the b-axis direction. The monoclinic crystal structure shown in FIG. 3 is almost the same as the hexagonal tungsten bronze having the hexagonal crystal structure shown in FIG. 1, but is slightly stretched in the b-axis direction and slightly tilted in the a-axis direction.

[0019] Even the orthorhombic and monoclinic crystal structures shown in Figures 2 and 3 have six-membered ring structures 11A formed by assembling six tungsten-oxygen octahedral blocks 11, and one-dimensional tunnel structures 12 in the direction perpendicular to the paper surface (c-axis direction).

[0020] The crystalline oriented film of this embodiment includes a six-membered ring structure 11A consisting of tungsten-oxygen octahedral blocks 11 and a one-dimensional tunnel structure 12, and the one-dimensional tunnel structure 12 is oriented in a direction perpendicular to the film surface of the crystalline oriented film. By having such a structure, the crystalline oriented film of this embodiment can be made into a crystalline oriented film with a high carrier density (free electron density).

[0021] Furthermore, by introducing oxygen vacancies into the tungsten-oxygen octahedral blocks, it is possible to obtain a crystal-oriented film with a particularly high carrier density.

[0022] The crystalline oriented film of this embodiment has a sheet shape, and therefore can exhibit high electrical properties even when it is thin. Furthermore, the crystalline oriented film of this embodiment can reduce light scattering of visible light and provide excellent visible light transmittance.

[0023] The crystalline oriented film of this embodiment has near-infrared shielding properties due to its high carrier density. The crystalline oriented film of this embodiment can selectively shield near-infrared radiation while transmitting visible light by absorbing or reflecting near-infrared radiation due to the carriers (free electrons) in the crystalline oriented film interacting with near-infrared radiation. Furthermore, the crystalline oriented film of this embodiment suppresses coloration such as blue in the transmitted color, resulting in less discomfort when viewed visually. The more coloration such as blue is suppressed in films that selectively transmit light, such as near-infrared shielding films, the easier it is to tone the color with other pigments or dyes, thereby expanding the range of applications.

[0024] As will be described later, the crystalline oriented film of this embodiment can be manufactured by, for example, spreading a molecular film, which is a precursor of the crystalline oriented film, on a substrate and heat-treating it in a reducing atmosphere.

[0025] The molecular film that is the precursor of the crystal orientation film of this embodiment is Cs6W having a layered crystal structure. 11 O 36 and Cs 8.5 W 15 O 48 The raw material can be a layered compound with a layered pyrochlore structure such as Cs6W. The molecular film can be produced by peeling the raw material such as the layered compound down to a single layer, which is the basic minimum unit of the crystal structure, using soft chemical processing. Depending on the conditions of the soft chemical processing, the molecular film can be made into a film equivalent to two or three layers, and a crystal-oriented film can also be produced using the molecular film. For example, the Cs6W shown in Figure 4(A) 11 O 36 The layered compound was peeled off to a single layer, and the Cs4W11 O 36 2- However, these compositions are just examples, and the general formula is Cs 6+A W 11 O 36 (0≦A≦0.31) and Cs 6+A-a W 11 O 36 a- (0≦a≦6.31).

[0026] The crystalline orientation film of this embodiment can have a sheet shape with a thickness of, for example, about 1 nm to 200 nm (corresponding to several to several hundred atoms).

[0027] The crystalline oriented film of this embodiment can be manufactured by arranging multiple molecular films having the above-mentioned layered crystalline structure on a base material (substrate) and then heat treating them. During the heat treatment, adjacent molecular films react with each other, resulting in the crystalline oriented film of this embodiment becoming a continuous polycrystalline film. However, the crystalline oriented film of this embodiment may contain voids resulting from the gaps between the molecular films arranged on the base material before the heat treatment.

[0028] During the heat treatment, it is preferable to carry out the heat treatment in an inert gas atmosphere, a vacuum atmosphere, or a reducing atmosphere, from the viewpoint of introducing oxygen vacancies into the tungsten-oxygen octahedral blocks contained in the molecular film as the raw material, thereby exhibiting particularly excellent electrical properties.

[0029] As described above, the crystallographically oriented film of this embodiment preferably includes a six-membered ring structure made of tungsten-oxygen octahedra and a one-dimensional tunnel structure, and the one-dimensional tunnel structure is oriented perpendicular to the film surface of the crystallographically oriented film. There are no particular limitations on the method for confirming that the crystallographically oriented film includes a six-membered ring structure made of tungsten-oxygen octahedra and a one-dimensional tunnel structure, and that the one-dimensional tunnel structure is oriented perpendicular to the film surface of the crystallographically oriented film. For example, this can be confirmed by analyzing an electron diffraction pattern measured using a transmission electron microscope or an X-ray diffraction (XRD) pattern measured using an XRD device.

[0030] The crystalline oriented film may be in the form of a sheet with a thickness of approximately 1 nm to 10 nm. Therefore, when measuring the structure of the crystalline oriented film of this embodiment using an X-ray diffractometer, it is necessary to measure the XRD pattern using thin-film X-ray diffraction rather than powder X-ray diffraction. Thin-film X-ray diffraction involves fixing the X-ray incident angle at a small angle of 0.5° or less, near the critical angle for total reflection. This allows the X-ray to penetrate the sample to a depth of several tens of nanometers, allowing the diffracted X-ray signal to be detected with high accuracy without being affected by the substrate. Thin-film X-ray diffraction methods include grazing incidence X-ray diffraction (GI-XRD) and in-plane X-ray diffraction, with in-plane X-ray diffraction being the most preferred. In-plane X-ray diffraction, also known as the φ-2θχ scan method, involves scanning the goniometer horizontally within the sample plane, making it important to accurately adjust the inclination and tilt axes within the sample plane. As a result, the angle of the incident X-rays can be controlled to less than 0.3°, making it possible to measure the crystalline state of ultra-thin films with a thickness of less than a few nm, as well as the orientation of the crystal planes in the direction perpendicular to the substrate surface. Examples of devices that can perform measurements using in-plane X-ray diffraction include the Rigaku SmartLab fully automated multipurpose X-ray diffractometer.

[0031] The crystalline alignment film and molecular film of this embodiment may be flexible and may have a bent sheet shape in a liquid, etc. Since the flexibility is maintained even in a solid, the crystalline alignment film can be bent together with a flexible substrate, for example, and even when bent, the structure of the atomic arrangement and the like within the crystalline alignment film is maintained without being destroyed. (2) Composition The crystal orientation film of this embodiment may contain a composite tungsten oxide. Alternatively, the crystal orientation film of this embodiment may be composed of only composite tungsten. However, even in this case, the inclusion of unavoidable impurities is not excluded.

[0032] The composite tungsten oxide that can be suitably contained in the crystal oriented film of this embodiment will be described below. (composite tungsten oxide) Tungsten oxide (WO3) is not an effective conductive material because it does not have any available free electrons.

[0033] On the other hand, WO 3-δ It is known that composite tungsten oxides, such as those made by adding electropositive elements like Na to WO3, are conductive materials with free electrons. Furthermore, analysis of single crystals of these materials with free electrons suggests that the free electrons respond to light in the infrared region.

[0034] By adding M, an element or atomic group (molecule) described below, to the above-mentioned WO3 to form a composite tungsten oxide, free electrons are generated in the WO3, making it effective as a conductive material. Furthermore, by introducing oxygen vacancies, it exhibits particularly excellent conductive properties.

[0035] That is, by controlling the amount of oxygen in WO3 and adding M, which generates free electrons, in combination, it is possible to obtain an excellent conductive material. For this reason, the crystal orientation film of this embodiment preferably contains a composite tungsten oxide. The general formula of the composite tungsten oxide obtained by controlling the amount of oxygen and adding M, which generates free electrons, in combination is M. x W y O zWhen expressed as above, it is preferable that x, y, and z satisfy the relationships 0.001≦x / y≦1 and 2.0≦z / y≦3.5. However, M in the above general formula can be one or more types selected from a group of elements and a group of atomic groups. The above element group includes H (hydrogen), Li (lithium), Na (sodium), K (potassium), Rb (rubidium), Cs (cesium), Be (beryllium), Mg (magnesium), Ca (calcium), Sr (strontium), Ba (barium), Sc (scandium), Y (yttrium), La (lanthanum), Ce (cerium), Pr (praseodymium), Nd (neodymium), Pm (promethium), Sm (samarium), Eu (europium), Gd (gadolinium), Tb (terbium), Dy (dysprosium), Ho (holmium), Er (erbium), Tm (thulium), Yb (ytterbium), Lu (lutetium), Ti (titanium), Zr (zirconium), Hf (hafnium), V (vanadium), Nb (niobium), Ta (Tantalum), Cr (Chromium), Mo (Molybdenum), Mn (Manganese), Re (Rhenium), Fe (Iron), Ru (Ruthenium), Os (Osmium), Co (Cobalt), Rh (Rhodium), Ir (Iridium), Ni (Nickel), Pd (Palladium), Pt (Platinum), Cu (Copper), Ag (Silver), Au (Gold), Zn (Zinc), Cd (Cadmium), B (Boron), Al ( Examples of the atomic group include tungsten (Aluminum), Ga (Gallium), In (Indium), Tl (Thallium), C (Carbon), Si (Silicon), Ge (Germanium), Sn (Tin), Pb (Lead), N (Nitrogen), P (Phosphorus), As (Arsenic), Sb (Antimony), Bi (Bismuth), S (Sulfur), Se (Selenium), Te (Tellurium), F (Fluorine), Cl (Chlorine), Br (Bromine), and I (Iodine). Examples of the atomic group include HO (Water), HO (Hydronium), and NH (Ammonium). In the above general formula, W represents tungsten, and O represents oxygen. The crystal oriented film of this embodiment can also contain a composite tungsten oxide as described above. In this case, the composite tungsten oxide contained in the crystal oriented film preferably satisfies the above general formula.

[0036] First, the value of x / y, which indicates the amount of M added, will be explained.

[0037] If the value of x / y is 0.001 or more, a sufficient amount of free electrons is generated in the composite tungsten oxide, and the desired electrical properties can be obtained. The more M is added, the more the supply of free electrons increases and the electrical properties also improve, but this effect saturates when the value of x / y is about 1. Furthermore, if the value of x / y is 1 or less, the generation of impurity phases can be suppressed, which is preferable.

[0038] Next, the z / y value, which indicates the control of the oxygen amount, will be explained. y O z In the case of tungsten oxide, which is expressed as z / y, free electrons can be generated by oxygen vacancies by making z / y less than 3. Therefore, in the case of tungsten oxide, electrical properties can be exhibited by making z / y less than 3.

[0039] In contrast, the general formula M x W y O z In the composite tungsten oxide represented by the general formula W y O z In addition to the mechanism similar to that of tungsten oxide expressed as z / y, even when z / y is 3≦z / y≦3.5, the addition of free electrons as described above is also possible. Furthermore, in a crystal-oriented film, the surface may be negatively charged, so even when z / y is 3.5, electrical properties may be exhibited due to the supply of free electrons. However, the WO2 crystalline phase may degrade electrical properties. Therefore, from the viewpoint of suppressing the generation of WO2, z / y is preferably 2.0 or greater. Therefore, 2.0≦z / y≦3.5 is preferred, 2.2≦z / y≦3.3 is more preferred, and 2.45≦z / y≦3.3 is even more preferred.

[0040] Here, from the viewpoint of enhancing the stability of the composite tungsten oxide, it is more preferable that M, which is an element or atomic group in the general formula of the composite tungsten oxide, contains one or more elements selected from H, Li, Na, K, Rb, Cs, Ca, Sr, Ba, Fe, Cu, Ag, In, Tl, Sn, Pb, and Yb.

[0041] The crystalline structure of the composite tungsten oxide is not particularly limited, and may have one or more structures selected from, for example, hexagonal, orthorhombic, monoclinic, cubic, tetragonal, and the like.

[0042] The composite tungsten oxide may have, for example, the atomic arrangement shown in FIG. 1 in the crystal oriented film of this embodiment.

[0043] As described above, six tungsten-oxygen octahedral blocks 11 are assembled to form one-dimensional tunnel structures 12, each of which is a hexagonal gap. M13 contained in the composite tungsten oxide is then arranged in the one-dimensional tunnel structure 12 to form a single unit, and many such units can be assembled. Such unit structures may be regularly or randomly arranged in the crystalline oriented film of this embodiment. The inclusion of such a structure in the crystalline oriented film of this embodiment particularly improves the transmission of light in the visible light region.

[0044] When M13 is added to the one-dimensional tunnel structure 12, which is the hexagonal void, light transmission in the visible light region is particularly improved, and electrical properties are particularly improved. Generally, the unit structure shown in FIG. 1 is easily formed when M13 with a large ionic radius or molecular size (atomic group size) is added. Specifically, the unit structure shown in FIG. 1 is easily formed when M contains one or more elements selected from the group consisting of Cs, Rb, K, Tl, In, Ba, Li, Ca, Sr, Fe, and Sn. Therefore, it is preferable that the composite tungsten oxide contains one or more elements selected from the group consisting of Cs, Rb, K, Tl, In, Ba, Li, Ca, Sr, Fe, and Sn as M. Note that M may also be composed of one or more elements selected from the above group of elements.

[0045] Furthermore, in a composite tungsten oxide containing one or more elements selected from Cs and Rb among these elements with large ionic radii, the unit structure shown in Figure 1 is easily formed, and it is possible to achieve both electrical properties and light transmission in the visible light range and to demonstrate particularly high performance. For this reason, it is more preferable that M contains one or more elements selected from Cs and Rb.

[0046] Of course, even if M includes an element or atomic group other than those mentioned above, it is sufficient that M13 exists in the one-dimensional tunnel structure 12, which is a hexagonal void formed by WO6 units, and it is not limited to the above elements. Also, some or all of M may be void.

[0047] When the composite tungsten oxide having the above structure has a uniform crystal structure, the amount of M added preferably satisfies the value of x / y, 0.001≦x / y≦1, and more preferably 0.2≦x / y≦0.6. (3) Characteristics of crystal orientation films As described above, in the crystalline orientation film of this embodiment, the one-dimensional tunnel structure is oriented in a direction perpendicular to the film surface of the crystalline orientation film. 5(B), when a crystal orientation film 62 is disposed on a substrate 61, the one-dimensional tunnel structure 12 is oriented perpendicular to a film surface 62A of the crystal orientation film 62 and the substrate 61. The tungsten-oxygen octahedral block 11, the six-membered ring structure 11A, and the element or atomic group M13 contained in the composite tungsten oxide have already been explained, and therefore further explanation will be omitted. Figure 5(A) is a cross-sectional view taken along line AA' in Figure 5(B), and Figure 5(B) is a side view of the crystalline orientation film 62 and the substrate-attached crystalline orientation film 60. Figures 5(A) and 5(B) show the arrangement of the one-dimensional tunnel structure 12 by schematically illustrating the atoms of the crystalline orientation film 62, and do not accurately represent the size ratio with the substrate 61, etc. The crystalline orientation film of this embodiment can include one or more crystallites. Therefore, as shown in Figure 6, for example, in a cross section of the crystalline orientation film 62 along the thickness direction, the crystalline orientation film 62 can include a crystallite 621, a crystallite 622, and a crystallite 623.

[0048] At this time, each crystallite has a one-dimensional tunnel structure oriented in a direction perpendicular to the film surface 62A, which is the upper surface of the crystal orientation film 62 (direction along the Y axis in FIG. 6). When a crystal-oriented film is analyzed by in-plane X-ray diffraction, the detected diffraction peaks are crystal planes perpendicular to the substrate 61 or film surface 62 A. Therefore, the crystal orientation corresponding to the crystal plane of the detected diffraction peak can be said to be a crystal orientation oriented in a direction parallel to the film surface or substrate.

[0049] Furthermore, among the crystal orientations of the crystals contained in the crystal orientation film, the crystal orientation that is perpendicular to all of the crystal orientations corresponding to the crystal planes of the detected diffraction peaks can be said to be a crystal orientation that is oriented perpendicular to the film surface or substrate.

[0050] The carrier density is particularly increased by the one-dimensional tunnel structure being oriented perpendicular to the substrate 61 and the film surface 62A of the crystal orientation film 62. This is because the one-dimensional tunnel structure, which is thought to be the oxygen diffusion path, is perpendicular to the substrate, so oxygen vacancies are introduced throughout the crystal orientation film, and uniform reduction occurs, resulting in a uniformly high carrier density throughout the crystal orientation film.

[0051] Furthermore, because the one-dimensional tunnel structure is oriented perpendicular to the substrate 61 and the film surface 62A of the crystal orientation film 62, coloration such as blue in the transmitted light can be suppressed. This is because the dielectric response of the electrons in the material, i.e., the interaction between light, which is an electromagnetic wave, and the electrons in the material, changes depending on the orientation of the one-dimensional tunnel structure.

[0052] The crystalline oriented film of this embodiment preferably contains crystals having any one of a hexagonal, orthorhombic, and monoclinic crystal structure. The crystalline oriented film of this embodiment may be any one of a hexagonal, orthorhombic, and monoclinic crystal structure, i.e., may be composed of crystals having any one of a hexagonal, orthorhombic, and monoclinic crystal structure. The crystal oriented film of this embodiment more preferably contains crystals having a hexagonal crystal structure. The crystal oriented film of this embodiment may be hexagonal, i.e., may be composed of crystals having a hexagonal crystal structure.

[0053] This is because the carrier density can be particularly increased by including crystals having a hexagonal crystal structure in the crystal oriented film. The crystal oriented film of this embodiment preferably includes a composite tungsten oxide containing, for example, Cs, and the composite tungsten oxide preferably has a hexagonal crystal structure.

[0054] The crystalline oriented film of this embodiment may also have chromic properties. Tungsten oxide and composite tungsten oxide, like other hydrated tungsten oxides, are known as both photochromic and electrochromic materials. The crystalline oriented film of this embodiment may also be both a photochromic and electrochromic material. The crystalline oriented film of this embodiment may also exhibit a photochromic reaction in response to high-energy light, such as ultraviolet light or visible light. Furthermore, if the energy threshold required for the reaction is low, it may also exhibit a photochromic reaction in response to infrared light. In response to ultraviolet light or visible light, cation species such as protons generated around the crystalline oriented film are adsorbed by the crystalline oriented film, creating a light absorption / reflection region. For this reason, it is preferable to increase the surface area of ​​photochromic materials so that they can adsorb a large number of cation species. It is also preferable to increase crystallinity so that the generation of light absorption regions due to the adsorption of cation species can be further enhanced. Examples of sources of protons in response to ultraviolet light or visible light include organic substances. Specific examples of sources of the protons include additives such as bulky guests typified by quaternary ammonium ions used in the soft chemical treatments described below, and resins used as matrices for the structures.

[0055] As described above, the crystalline oriented film of this embodiment has a high carrier density and can be used in semiconductors and various applications requiring desired electrical properties. In addition, the crystalline oriented film of this embodiment has high visible light transmittance and near-infrared shielding properties, and the transmitted light is not colored blue or the like, so it can also be used as a near-infrared shielding film and various applications requiring desired optical properties.

[0056] The electrical properties of the crystalline orientation film of this embodiment are not particularly limited, but the mobility of the crystalline orientation film of this embodiment is 0.01 cm 2 / (V·s) or more 1000cm 2 / (V·s) or less is preferable, and 0.1 cm 2 / (V·s) or more 500cm 2 / (V·s) or less is more preferable, and 0.1 cm2 / (V·s) or more 100cm 2 It is more preferable that the value is not more than / (V·s).

[0057] The carrier density of the crystal orientation film of this embodiment is 1.0×10 19 / cm 3 Over 1.0 x 10 24 / cm 3 Preferably, it is 1.0 x 10 or less. 20 / cm 3 Over 1.0 x 10 23 / cm 3 More preferably, it is 1.0×10 or less. 21 / cm 3 Over 1.0 x 10 23 / cm 3 It is even more preferable that:

[0058] The crystalline oriented film of this embodiment preferably satisfies the above-mentioned preferred range for either the mobility or the carrier density, and more preferably satisfies the above-mentioned preferred range for both. The visible light transmittance of the crystalline orientation film of this embodiment is preferably 60% or more and 100% or less, and more preferably 70% or more and 95% or less.

[0059] Furthermore, the minimum transmittance of the crystalline orientation film of this embodiment for light in the near-infrared region with wavelengths of 780 nm or more and 2600 nm or less is preferably 70% or less.

[0060] Furthermore, it is preferable that the maximum value of the reflectance of the crystal orientation film of this embodiment for light in the near-infrared region with a wavelength of 780 nm or more and 2600 nm or less is 10% or more.

[0061] In addition, the crystal orientation film of this embodiment has a blue coloring index b * is preferably 0 or more, and more preferably 2 or more.

[0062] b * L * yaa *The results are as follows: First, the transmitted light profile is measured at 5 nm intervals in the wavelength range of 380 nm to 780 nm. Next, tristimulus values ​​X, Y, and Z for the D65 standard light source and a light source angle of 10° are calculated based on JIS Z 8701 (1999). From the obtained tristimulus values ​​X, Y, and Z, the L * a * b * The color index can be obtained.

[0063] The crystal orientation film of this embodiment is preferably in the form of a film.

[0064] A crystal orientation film is easier to form into a film when the number of molecular film layers in the manufacturing process is 5 or more, which is particularly preferable from the viewpoint of achieving both high electrical properties and visible light transmittance. The number of molecular film layers corresponds to the number of coatings (layering times) on a substrate in the coating process when manufacturing the crystal orientation film, and corresponds to the number of repetitions of a series of coating operations in the coating process described in the Examples below. The greater the number of molecular film layers, the thicker the crystal orientation film will be; when the number of layers is 5 or more, the film thickness can be 9 nm or more.

[0065] As mentioned above, the thickness (film thickness) of the crystalline oriented film of this embodiment is not particularly limited and can be, for example, 1 nm or more and 200 nm or less. In the crystalline oriented film of this embodiment, as mentioned above, the lower limit of the film thickness is preferably 9 nm or more. That is, the film thickness of the crystalline oriented film of this embodiment is preferably 9 nm or more and 200 nm or less.

[0066] Furthermore, in the crystalline orientation film 62 of this embodiment, the average length (average length) of the contained crystallites along the film surface 62A of the crystalline orientation film 62 is preferably 100 nm or more, more preferably 300 nm or more and 1 mm or less, and even more preferably 1 μm or more and 1 mm or less.

[0067] In the oriented crystal film of this embodiment, the electrical properties can be particularly improved by making the average length of the contained crystallites 100 nm or more.

[0068] In addition, the crystal orientation film of this embodiment preferably has an average thickness (average thickness) of the contained crystallites of 2 nm or more, more preferably 3 nm to 100 nm, even more preferably 5 nm to 100 nm, and particularly preferably 10 nm to 50 nm. In the crystal orientation film of this embodiment, by making the average thickness of the contained crystallites 2 nm or more, the electrical properties can be particularly improved.

[0069] The average length and thickness of the crystallites can be set within the above-mentioned ranges by selecting the crystal size of the composite tungsten oxide having a layered crystal structure before exfoliation, which is used as the raw material, and the conditions of the heat treatment.

[0070] The average crystallite length can be calculated from an image of a cross section of a crystal-oriented film along the thickness direction observed with a transmission electron microscope (TEM). The average crystallite length is the average of the maximum lengths of the crystallites along the film surface 62A measured for a plurality of arbitrarily selected crystallites in the observed image. The number of crystallites measured is not particularly limited, but is preferably 5 to 20, for example.

[0071] The average crystallite thickness is the average value of the crystallite thickness measured at multiple measurement points in the observation image, each of which is spaced apart by 20 nm to 100 nm, along the thickness direction of the molecular film, etc. The number of measurement points is not particularly limited, but is preferably 5 to 20 points, for example. In this specification, the thickness (film thickness) of the crystal orientation film is the average value of thicknesses measured at a plurality of arbitrarily selected measurement points in the above-mentioned observation image. The number of measurement points is not particularly limited, but is preferably, for example, 5 to 20 points. (4) Structure of crystal orientation film The crystalline orientation film may be disposed on a substrate 61 as shown in FIG. 6 to form a substrate-attached crystalline orientation film 60. FIG. 6 is a schematic cross-sectional view of a plane perpendicular to the substrate. In the case of a substrate-attached crystalline orientation film 60, FIG. 6 shows an example in which a crystalline orientation film 62 is disposed only on one surface 61A of the substrate 61, but a crystalline orientation film may also be disposed on the other surface 61B of the substrate 61. The crystalline orientation film disposed on one surface 61A and the crystalline orientation film disposed on the other surface 61B may differ in material content, composition, etc.

[0072] The crystalline alignment film can also be constructed solely from the crystalline alignment film, in a locally supported, free-standing state without a substrate. Even without a substrate, the crystalline alignment film can still exhibit its electrical properties.

[0073] When the crystal orientation film 62 is disposed on the substrate 61, the substrate 61 may be any substrate capable of supporting the crystal orientation film, and there are no particular limitations on the material or shape thereof. Because crystal orientation films are often used for transparent electrodes in displays, the crystal orientation film preferably has a shape of a sheet, board, or film. Therefore, the substrate 61 also preferably has a shape of a sheet, board, or film.

[0074] The material of the substrate 61 is not particularly limited, and can be selected depending on the wavelength range of light that is required to be transmitted, absorbed, and reflected by the crystal orientation film, as well as the strength, thickness, and other factors required by the crystal orientation film.

[0075] The substrate 61 may include one or more materials selected from a single crystal material, a polycrystalline material, glass, a metal, an alloy, a ceramic, and a resin. The substrate 61 may be made of any of the above materials, and may be a single crystal material substrate, a polycrystalline material substrate, a glass substrate, a metal substrate, an alloy substrate, a ceramic substrate, or a resin substrate. Furthermore, the substrate 61 may have a coating provided on its surface as needed.

[0076] When the substrate 61 includes a single crystal material, the single crystal material is not particularly limited, and examples thereof include a silicon substrate, a silicon substrate with an oxide film, a silver substrate, an aluminum substrate, a gold substrate, a bismuth substrate, a cadmium substrate, a cobalt substrate, a chromium substrate, a copper substrate, a dysprosium substrate, an erbium substrate, an iron substrate, a germanium substrate, a gadolinium substrate, a hafnium substrate, a holmium substrate, an indium substrate, an iridium substrate, a lithium substrate, a magnesium substrate, a molybdenum substrate, a niobium substrate, a nickel substrate, a nickel aluminum substrate, a lead substrate, a palladium substrate, a platinum substrate, a rhenium substrate, a rhodium substrate, a ruthenium substrate, an antimony substrate, a tin substrate, a tantalum substrate, a terbium substrate, a tellurium substrate, a titanium substrate, a vanadium substrate, a tungsten substrate, a yttrium substrate, a zinc substrate, a zirconium substrate, an alloy crystal substrate, a silicon carbide substrate, a gallium nitride substrate, a gallium phosphide substrate, an indium phosphide substrate, a and at least one substrate selected from the group consisting of silicon substrate, lithium fluoride substrate, lanthanum fluoride substrate, magnesium fluoride substrate, strontium fluoride substrate, potassium bromide substrate, potassium chloride substrate, sodium chloride substrate, mica substrate, aluminum oxide substrate, titanium oxide substrate, cobalt oxide substrate, chromium oxide substrate, manganese oxide substrate, nickel oxide substrate, tin oxide substrate, zinc oxide substrate, copper oxide substrate, iron oxide substrate, strontium titanate substrate, lithium niobate substrate, lithium tantalate substrate, potassium tantalate substrate, yttrium aluminate substrate, lanthanum aluminate substrate, lanthanum strontium aluminate substrate, lanthanum strontium gallate substrate, dysprosium scandate substrate, gadolinium scandate substrate, neodymium scandate substrate, gadolinium gallium garnet substrate, and yttrium aluminum garnet substrate.

[0077] When the base material 61 contains a polycrystalline material, a substrate made of the same material as the single crystal material described above can be suitably used, except that the constituent material is polycrystalline.

[0078] When the substrate 61 contains glass, the glass material is not particularly limited, but is preferably one or more types selected from various functional glasses such as fused silica glass, synthetic quartz glass, soda-lime glass, borosilicate glass, crystal glass, alkali-free glass, lead glass, uranium glass, tempered glass, heat-resistant glass, heat-absorbing glass, and Low-E glass.

[0079] When the substrate 61 contains a metal, the specific material is not particularly limited, but is preferably one or more selected from, for example, silver, aluminum, gold, bismuth, cadmium, cobalt, chromium, copper, dysprosium, erbium, iron, gallium, germanium, gadolinium, hafnium, holmium, indium, iridium, lithium, magnesium, molybdenum, niobium, nickel, lead, palladium, platinum, rhenium, rhodium, ruthenium, antimony, scandium, tin, tantalum, terbium, titanium, vanadium, tungsten, yttrium, zinc, and zirconium.

[0080] When the substrate 61 contains an alloy, the material is not particularly limited, but the alloy is preferably one or more selected from the group consisting of aluminum alloy, gold alloy, cobalt alloy, chromium alloy, copper alloy, iron-based alloy, germanium alloy, magnesium alloy, manganese alloy, nickel alloy, palladium alloy, platinum alloy, titanium alloy, tungsten alloy, zirconium alloy, and SUS (stainless steel).

[0081] When the substrate 61 includes ceramics, the specific material is not particularly limited, but the ceramic may be, for example, one or more types selected from borides, carbides, and nitrides in addition to oxides. Note that ceramics overlap with single crystal materials, polycrystalline materials, and glass to some extent.

[0082] When the substrate 61 contains a resin, the resin to be used is not particularly limited, but it is preferable that the resin does not cause any problems in the surface condition or durability of the substrate containing the resin. Examples of the resin include polyester polymers such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and polyethylene-2,6-naphthalate; cellulose polymers such as diacetyl cellulose and triacetyl cellulose; carbonate polymers such as polycarbonate; acrylic polymers such as polymethyl methacrylate; styrene polymers such as polystyrene and acrylonitrile-styrene copolymers; olefin polymers such as polyethylene, polypropylene, polyolefins having a cyclic or norbornene structure, and ethylene-propylene copolymers; amide polymers such as vinyl chloride polymers and aromatic polyamides; ether polymers such as polyethersulfone and polyetheretherketone; imide polymers; sulfone polymers; phenylene sulfide polymers; vinylidene chloride polymers; oxymethylene polymers; epoxy polymers; vinyl alcohol polymers; and polyvinyl acetals such as polyvinyl butyral. Examples of the resin include any of various binary and ternary copolymers, graft copolymers, and blends of two or more resins selected from these resin groups. When the substrate 61 contains a resin, the resin is preferably one or more selected from polyethylene terephthalate, polybutylene terephthalate, polyethylene-2,6-naphthalate, polycarbonate, polymethyl methacrylate, and polyvinyl butyral, and it is particularly preferable that the substrate 61 is a biaxially oriented polyester film such as the polyethylene terephthalate film in terms of mechanical properties, optical properties, heat resistance, and cost efficiency. The biaxially oriented polyester film may be a copolymer polyester film.

[0083] The thickness of the substrate 61 is not particularly limited and can be selected depending on the strength and optical properties required of the crystal orientation film, etc. For example, it is preferably 0.001 mm or more and 100 mm or less, and more preferably 0.01 mm or more and 30 mm or less. [Method of manufacturing crystal orientation film] Next, a method for manufacturing a crystal orientation film according to this embodiment will be described. Since the method for manufacturing a crystal orientation film according to this embodiment can manufacture the crystal orientation film already described, a description of the matters already described will be omitted.

[0084] The method for producing a crystal orientation film of this embodiment can include the following molecular film formation step, coating step, and heat treatment step.

[0085] In the molecular film formation step, a molecular film containing tungsten as an element can be produced.

[0086] In the coating step, the molecular film can be coated onto the substrate.

[0087] In the heat treatment step, the molecular film coated on the substrate can be heat treated at a temperature of 650°C or higher and 750°C or lower in a reducing atmosphere.

[0088] Each step will be described below. (1)Molecular film formation process In the method for producing a crystal-oriented film according to this embodiment, for example, a composite tungsten oxide having a layered crystal structure can be used as a raw material. The raw material having a layered crystal structure can be peeled off into one or more layers, which are the basic minimum units of the crystal structure, by soft chemical processing, to obtain a molecular film. Furthermore, by subjecting this to reduction processing, a crystal-oriented film with excellent electrical properties can be obtained.

[0089] Soft chemical treatment is a combination of acid treatment and colloidal treatment. Specifically, a composite tungsten oxide powder having a layered crystal structure is contacted with an aqueous acid solution such as hydrochloric acid. The resulting product is filtered, washed, and then dried. Some or all of the alkali metal ions present between the layers before the acid treatment are exchanged for hydrogen ions, resulting in a hydrogen-type substance. The resulting hydrogen-type substance is then placed in an aqueous solution such as an amine and stirred to form a colloid. During this process, the layers that constituted the layered crystal structure are peeled off one by one. The layers that constituted the layered crystal structure specifically refer to oxides containing elemental tungsten, such as those with a basic skeleton consisting of a repeating tungsten-oxygen octahedral block structure.

[0090] Therefore, the molecular film forming step in the method for producing a crystal orientation film of this embodiment can include the following acid treatment step and colloidal formation step.

[0091] In the acid treatment step, a raw material having a layered crystal structure is brought into contact with an aqueous acid solution, and the product is washed and dried to obtain a hydrogen-type substance.

[0092] In the colloidal process, a hydrogen-type substance is mixed with a liquid containing a bulky guest to obtain a molecular film.

[0093] As a raw material having a layered crystal structure, for example, a composite tungsten oxide can be used. 6+A W 11 O 36 (0≦A≦0.31), Cs 8+B W 15 O 48 It is preferable that the composite tungsten oxide contains one or more composite tungsten oxides selected from the group consisting of (0≦B≦0.5). These composite tungsten oxides have alkali metal ions of Cs present between the layers.

[0094] In soft chemical treatment, for example, a composite tungsten oxide powder having a layered crystal structure is brought into contact with an acid solution to obtain a hydrogen-type substance. 6+A-a Ha W 11 O 36 (0≦a≦6.31), Cs 8+B-b H b W 15 O 48 (0≦b≦8.5) to obtain hydrogen-type materials. These hydrogen-type materials are obtained by exchanging some or all of the alkali metal ions and cations that existed between the layers before acid treatment for hydrogen ions. The hydrogen-type materials become hydrates in aqueous solution, and even after filtration, washing, and drying, they retain this hydrate when air-dried at room temperature. It is also possible to obtain materials in which hydrogen H is replaced by oxonium.

[0095] The acid solution used for the acid treatment is not particularly limited as long as it does not dissolve the composite tungsten oxide, and hydrochloric acid, nitric acid, sulfuric acid, carbonic acid, etc. can be used. The ion exchange capacity can be changed by changing the type and concentration of the acid and the number of treatments.

[0096] Next, by inserting a bulky guest between the layers of the hydrogen-type substance, which is the acid-treated product, the hydrogen-type substance can be exfoliated into a single layer, which is the basic minimum unit of the crystal structure, and a sheet-shaped molecular film can be obtained. 6+A-a W 11 O 36 a- (0≦a≦6.31), Cs 8+B-b W 15 O 48 b- A crystal orientation film with a lattice constant of (0≦b≦8.5) can be obtained. When the molecular film is strictly cut, it is obtained in a negatively charged state, but because the bulky guest compounds modify the surface of the molecular film as cations, the overall state, including the bulky guest compounds, is thought to be close to neutral.

[0097] Bulky guests, such as quaternary ammonium ions, are used by contacting them with a hydrogen-type substance in a liquid such as water or an organic solvent. For example, a bulky guest supplying material, such as a quaternary ammonium salt, is dissolved in a suitable liquid, the hydrogen-type substance is added thereto, and the liquid is mixed and shaken to exfoliate the hydrogen-type substance into a single layer.

[0098] As the ion serving as a bulky guest, one or more kinds of quaternary ammonium ions selected from tetrabutylammonium ion, tetrapropylammonium ion, tetraethylammonium ion, tetramethylammonium ion, etc. can be preferably used. However, tetrabutylammonium ion (hereinafter referred to as "TBA + ") can be particularly preferably used. As a material for supplying a bulky guest, the above-mentioned quaternary ammonium salts can be preferably used, and tetrabutylammonium hydroxide can be particularly preferably used.

[0099] For example, the composite tungsten oxide having a layered crystal structure as the raw material is Cs6W shown in Figure 4(A). 11 O 36 Consider the case where Cs6W is used. 11 O 36 has a layered crystal structure in which layers of a repeating structure of tungsten-oxygen octahedral blocks (hereinafter also referred to as "octahedral block layers") and faces containing only Cs (hereinafter also referred to as "Cs faces") are alternately stacked. In other words, it has a structure in which Cs faces containing the alkali metal Cs are arranged between the layers of the octahedral block layers. The structure of the octahedral block layers is a pyrochlore structure. Cs6W, which has this layered crystal structure, 11 O 36When the Cs-containing octahedron block layer is subjected to acid treatment, some or all of the Cs present on the Cs-containing octahedron surface is extracted as ions into the aqueous acid solution, and hydrogen ions or oxonium ions are introduced into the voids, yielding a hydrogen-type material. Depending on the acid treatment conditions, Cs within the octahedron block layer structure may also be extracted during the acid treatment. The hydrogen-type material is then added to a liquid containing quaternary ammonium ions, which function as bulky guests, and the liquid is mixed and shaken. This procedure allows the hydrogen-type material to be peeled off into a single layer while preserving the six-membered ring structure of the octahedron block layer and the one-dimensional tunnel structure of Cs. A molecular film of the octahedron block layer is then obtained. Because the quaternary ammonium ions, which function as bulky guests, act as a surface modifier and dispersant for the molecular film, the molecular film is obtained in a dispersed state in the liquid, i.e., a dispersion containing the molecular film is obtained. This dispersion can be used as a coating liquid, for example, in the coating process described below.

[0100] Depending on the acid treatment conditions such as the type, concentration, and number of treatments, for example, the general formula Cs 6-a H a W 11 O 36 The amount of a in the hydrogen-type substance, expressed as (0≦a≦6), i.e., the amount of ion exchange, can be changed. For example, when all of the Cs present on the Cs plane is ion-exchanged, a=2, and it is Cs4H2W 11 O 36 The hydrogen-type material Cs4W 11 O 36 2- A molecular film of Cs4W is obtained. 11 O 36 2- The surface of the molecular film is negatively charged. Normally, the maximum valence of W is 6+, so the crystal orientation film has a charge state of -2. However, since the bulky guest ions modify the surface of the molecular film as cations at the same time as the molecular film is obtained, the overall state, including the bulky guest ions, is thought to be close to neutral.

[0101] To fully promote the reaction that separates the hydrogen-type material into a single layer after acid treatment, it is preferable to carry out ion exchange with a=2 or more, which corresponds to the amount of Cs ions present on the Cs plane, i.e., the amount of Cs ions present between the octahedral block layers. Therefore, it is preferable to carry out acid treatment so that a in the above general formula is 2 or more, and it is preferable to carry out acid treatment with hydrochloric acid, nitric acid, sulfuric acid, or carbonic acid at a concentration of 6N or more, at a solid-liquid ratio of (solid) / (aqueous solution)=10g / L or less. However, this is because the raw material is Cs6W 11 O 36 These are the preferred acid treatment conditions when using the above, and the preferred conditions vary depending on the raw material used.

[0102] The amount of the bulky guest added is not particularly limited. For example, Cs 6-a H a W 11 O 36 TBA, a bulky guest ion relative to the hydrogen ion amount of the hydrogen-type substance represented by (0≦a≦6) + It is preferable to add the compound so that the molar ratio is in the range of 0.5 to 2. By setting the molar ratio at 0.5 or more, it is possible to promote delamination between layers particularly sufficiently. Furthermore, by setting the molar ratio at 2 or less, it is possible to prevent the crystal structure of the hydrogen-type substance and the molecular film from collapsing. More preferably, when the molar ratio is about 1, it is possible to obtain the molecular film in the highest yield.

[0103] The size of the resulting molecular film is not particularly limited, but it can have a thickness equivalent to that of a single octahedral block layer, for example, a thickness of 1 nm to 3 nm. The thickness of the raw material molecular film is not limited to this range, and the thickness can be selected depending on the raw material used, etc.

[0104] The longitudinal length of the resulting molecular film can be, for example, 20 nm or more and 1 mm or less. That is, the aspect ratio can be, for example, 7 or more and 1,000,000 or less. This can be controlled by adjusting the synthesis (calcination) temperature of the starting composite tungsten oxide having a layered crystal structure, or by using a composite tungsten oxide or a single crystal of tungsten oxide. Furthermore, the molecular film can be destroyed by stirring or ultrasonic irradiation of the dispersion containing the resulting molecular film. Therefore, for example, by applying gentle stirring, the width (longitudinal length) can be controlled to 1 μm or more, and by applying strong shear force such as ultrasonic irradiation, the width can be controlled to 1 μm or less. However, it is currently difficult to synthesize a giant molecular film longer than 1 mm.

[0105] Any unreacted material generated in the above reaction can be removed by further centrifuging the resulting dispersion containing the molecular film. (2) Coating process In the coating process, a molecular film can be coated on a substrate. Specifically, in the coating process, a dispersion containing a molecular film can be coated on at least one surface of the substrate. This makes it possible to obtain a molecular film on the substrate or a molecular film assembly in which multiple molecular films are stacked. Here, the dispersion containing a molecular film is referred to as the coating liquid.

[0106] A surfactant may be added to the dispersion containing the molecular film to form a coating liquid, for example, for the purpose of applying the coating uniformly to the substrate. Various surfactants, such as nonionic, anionic, cationic, and amphoteric surfactants, can be used depending on the purpose and the material of the substrate.

[0107] The method for applying the coating liquid to the substrate surface is not particularly limited, but it is preferable to apply the coating liquid uniformly so that the substrate surface and the main surface of the molecular film are parallel. For example, the coating liquid can be applied to the substrate surface by wet methods such as bar coating, dip coating, electrophoresis, spray coating, spin coating, Langmuir-Blodgett (LB) method, layer-by-layer method, and the single-droplet assembly method described in Non-Patent Document 1. The molecular film contained in the dispersion has a large aspect ratio, so the substrate surface and the main surface of the molecular film are likely to be parallel, regardless of the application method, making it easy to apply the coating uniformly. Furthermore, from the perspective of applying only a single layer of the molecular film over a wide area while accumulating the molecular film, it is more preferable to use one or more methods selected from spin coating, Langmuir-Blodgett, layer-by-layer adsorption, and single-droplet assembly. Among these, the single droplet assembly method is particularly preferred because it is simple and minimizes the consumption of molecular film.

[0108] After the coating liquid is applied to the surface of the substrate, drying or heat treatment at a temperature lower than the heat treatment temperature in the heat treatment step described below may be carried out as needed.

[0109] The coating step may be repeated, or the coating step and the heat treatment such as drying may be alternately repeated. In the coating process, it is preferable that the number of layers of the molecular film is 5 or more. In other words, it is preferable that the number of coatings (layers) on the substrate is 5 or more. This is because the crystal orientation film is easier to form into a film when the number of layers of the molecular film in the manufacturing process is 5 or more, which is more preferable from the viewpoint of achieving both high electrical properties and visible light transmittance. (3) Heat treatment process In the heat treatment step, the molecular film coated on the substrate can be heat treated at a temperature of 650°C or higher and 750°C or lower in a reducing atmosphere.

[0110] The reducing gas used in the reducing atmosphere is not particularly limited, but H2 (hydrogen) is preferred. When H2 is used as the reducing gas, the reducing atmosphere is preferably composed of an inert gas such as Ar or N2, with H2 mixed in an amount of more than 0% to 5.0% by volume. The inert gas is also not particularly limited, but from the viewpoint of cost, one or more selected from the above-mentioned Ar and N2 are preferred.

[0111] The heat treatment temperature is not particularly limited, but is preferably 650°C to 750°C, more preferably 670°C to 750°C, and even more preferably 700°C to 730°C. In the heat treatment process, heat treatment at 650°C or higher rearranges the atoms contained in the molecular film, producing a crystallographically oriented film containing a six-membered ring structure consisting of tungsten-oxygen octahedra and a one-dimensional tunnel structure, with the one-dimensional tunnel structure oriented perpendicular to the film surface of the crystallographically oriented film. Furthermore, oxygen vacancies can be introduced into the tungsten-oxygen octahedra, increasing carrier density. Heat treatment at 650°C or higher can promote reactions, particularly between adjacent molecular films, and increase crystallite size. Heat treatment at 750°C or lower can suppress the generation of by-products, reactions between the crystallographically oriented film and the substrate, and sublimation of the molecular film. (4) Separation process The method for producing a crystal orientation film according to this embodiment may further include any optional step, such as a separation step of separating the crystal orientation film from the substrate. Depending on the material of the substrate, the crystal orientation film may be separated from the substrate by, for example, dissolving only the substrate or peeling the crystal orientation film from the substrate. The separated crystal orientation film may be placed on another substrate or placed in a structure, as described below. [Structure] Next, the structure of this embodiment will be described.

[0112] The structure of this embodiment can include the above-mentioned crystal orientation film.

[0113] The structure of this embodiment may have a matrix such as a solid medium and the above-mentioned crystal orientation film disposed in the matrix. A conductive matrix having electrical conductivity can be suitably used as the matrix.

[0114] As described above, the structure of this embodiment can have a matrix of an appropriate solid medium having electrical conductivity and the above-mentioned crystal orientation film, which is a filler, arranged in the matrix by kneading, etc. The matrix generally refers to a base material, but here it refers to a solid medium into which the crystal orientation film, etc., which is a filler, is kneaded.

[0115] The structure of this embodiment can have a matrix 71 and a crystal orientation film 62 disposed within the matrix 71, as in the structure 70 shown in Fig. 7. In the drawings explaining the structure such as Fig. 7, the crystallites in the crystal orientation film 62 are omitted.

[0116] The structure of this embodiment can have a matrix 71 and a substrate-attached crystalline oriented film 60 disposed within the matrix 71, as in the structure 80 shown in Fig. 8. The structure 80 shown in Fig. 8 illustrates an example in which the substrate-attached crystalline oriented film 60 is formed from a substrate 61 and a crystalline oriented film 62 disposed on the substrate 61, and then disposed within the matrix 71.

[0117] In this way, the structure of this embodiment can have a substrate-attached crystalline oriented film kneaded into the matrix together with the substrate, that is, the structure can include the substrate in the matrix.

[0118] 9, the structure of this embodiment may also have a substrate. That is, the structure 90 may have a substrate 91 and a matrix 71 containing the above-described crystal orientation film 62 provided on the substrate 91.

[0119] For example, as in the case of the structure 100 shown in Figure 10, the crystalline orientation film placed within the matrix 71 can also be in the form of a substrate-attached crystalline orientation film 60 in which a crystalline orientation film 62 is placed on a substrate 61.

[0120] Furthermore, like the structure 110 shown in FIG. 11, the structure of this embodiment can further contain conductive particles 111. The conductive particles 111 can be arranged, for example, in the matrix 71. The conductive particles 111 are a component other than the crystal orientation film or the crystal orientation film with a substrate. There are no particular limitations on the conductive particles 111, and various conductive materials can be used. Examples of conductive particles include metal particles such as Ag and Au, WO 3-x Tungsten oxide particles such as Cs 0.33 WO 3-x hexaboride particles such as LaB6; element-doped indium oxide particles such as In2O3:Sn; element-doped tin oxide particles such as SnO2:Sb; and element-doped zinc oxide particles such as ZnO:Ga.

[0121] In the structure 110, the matrix 71 containing the conductive particles 111 and the crystal orientation film 62 can also be provided on the base material 91. The structure 110 does not necessarily have to have the base material 91.

[0122] The matrix may be any matrix into which the crystal orientation film can be kneaded, and its shape is not particularly limited. Since the structure of this embodiment is often used for electrodes, electric circuits, etc., it is preferable that it has any one of a sheet shape, a board shape, and a film shape. Therefore, it is preferable that the matrix also has any one of a sheet shape, a board shape, and a film shape.

[0123] The matrix material is not particularly limited and can be selected depending on the wavelength range of light that is required to be transmitted, absorbed, or reflected by the structure, as well as the strength, thickness, electrical properties, and the like that are required by the structure.

[0124] The matrix may contain the same material as the substrate described above in the substrate-attached crystal oriented film, but preferably contains a resin from the viewpoint of lightweight, economical, and durable properties, as well as the ease and processability required when kneading the crystal oriented film, etc. Since resin has a low softening point, it is easy to obtain a sheet-, board-, or film-shaped matrix kneaded with the crystal oriented film, etc., filler, by melt mixing and stretching processing, etc.

[0125] The resin to be used is not particularly limited, but is preferably one that does not cause problems with the surface condition or durability of the matrix containing the resin. The resin can be suitably selected from the materials described above when the substrate 61 contains a resin. The resin is preferably one or more conductive polymers selected from polyacetylene, polythiophene, poly(p-phenylene vinylene), polypyrrole, polyaniline, and poly(p-phenylene sulfide), in terms of electrical properties, mechanical properties, optical properties, heat resistance, and cost efficiency.

[0126] The material of the substrate 91 is not particularly limited, and for example, the same material as the substrate 61 described for the substrate-attached crystalline orientation film 60 can be suitably used. [Example]

[0127] The present invention will be specifically described below with reference to examples, although the present invention is not limited to the following examples. [Example 1] (1)Molecular film formation process First, a coating solution was prepared according to the following procedure.

[0128] 4.30 g of cesium carbonate and 10.70 g of tungsten (VI) oxide were mixed so that the Cs:W molar ratio was 6.3:11, and the mixture was fired at 900°C for 5 hours in an air atmosphere. The powder X-ray diffraction pattern of the fired product indicated Cs6W 11 O 36 The composition is shown in the composition column of the fired product in Table 1. 11 O 36It was also confirmed that the compound has a pyrochlore crystal structure with a basic framework consisting of repeating tungsten-oxygen octahedral blocks.

[0129] The obtained Cs6W 11 O 36 0.5 g of this was taken and added to 50 mL of 12 N hydrochloric acid, and the mixture was left at room temperature for one day, i.e., without any heat treatment such as heating or cooling, for acid treatment. After removing the hydrochloric acid by decantation, the mixture was replaced with fresh hydrochloric acid and similar acid treatment was carried out for an additional day (a total of two days of acid treatment), followed by filtration, washing with water, and air drying to recover the solid residue that was the acid treatment product (acid treatment step).

[0130] The Cs and W concentrations of the obtained solid residue were analyzed using an ICP atomic emission spectrometer (Shimadzu Corporation, Model ICPE-9000), and were found to be 17 wt% and 65 wt%, respectively. Furthermore, the chemical formula was calculated from the results, and it was confirmed that the solid residue had a molar ratio of Cs / W = 4 / 11. The analysis results of the above hydrogen-type substance, which is the solid residue obtained after the acid treatment process, are shown in the hydrogen-type substance column of Table 1. Specifically, in the hydrogen-type substance column in Table 1, the columns for each element indicated by Cs and W show the mass proportions of each element in the obtained hydrogen-type substance, and the Cs / W column shows the molar ratio of Cs to W.

[0131] 0.4 g of the resulting solid residue was added to 100 cm of a 0.0029 mol / L aqueous solution of tetrabutylammonium hydroxide. 3 The mixture was stirred at 150 rpm for 7 days, and then the precipitated components were removed by centrifugation. 11 O 36 2- A dispersion containing a molecular film of the above was obtained (colloidization step). Here, the molecular film was obtained in a negatively charged state, but the surface of the molecular film was charged with tetrabutylammonium ions (TBA + It is thought that the overall state is close to neutral.

[0132] The obtained Cs4W 11 O 36 2-A dispersion containing the molecular film was dropped onto a microgrid for observation of transmission electron microscope images, and the molecular film was transferred and observed by transmission electron microscope. For the 10 molecular films observed for morphology, it was confirmed that the average longitudinal length of the molecular film was 5 μm. Furthermore, analysis of the crystal structure from the electron diffraction pattern of the molecular film revealed that the obtained molecular film was the same as that of Cs6W before acid treatment. 11 O 36 As in the previous study, it was confirmed that the molecular film has a basic skeleton consisting of a repeating structure of tungsten-oxygen octahedral blocks.

[0133] The obtained Cs4W 11 O 36 2- 0.1 mL of the dispersion containing the molecular film, 5.0 mL of pure water, and 0.03 mL of ethanol were mixed together to prepare a coating liquid according to Example 1. (2) Coating process The coating operation was carried out by the single droplet accumulation method using the coating solution according to Example 1. After heating the quartz substrate, which is the base material, to a temperature of 120°C using a hot plate, the coating solution according to Example 1 was dropped onto the base material, and then the supplied coating solution was slowly sucked up with a pipette to form a Cs4W 11 O 36 2- A molecular film assembly composed of these was fabricated on a quartz substrate, and then dried at 200°C for 3 minutes to adhere the molecular film assembly to the quartz substrate.

[0134] The series of coating steps using the single droplet assembly method was repeated a total of eight times to stack molecular film assemblies. This resulted in eight molecular films and molecular film assemblies stacked together, i.e., an eight-layer stack with eight molecular film layers. The number of times the coating steps were repeated is shown in the "Number of Layers" column in Table 1.

[0135] The X-ray diffraction pattern of the molecular film assembly, which is a coating of molecular film formed on a quartz substrate, was measured using in-plane X-ray diffraction with an X-ray diffractometer. Analysis of the X-ray diffraction pattern confirmed that the molecular film assembly contains a molecular film with a pyrochlore crystal structure, whose basic structure is a repeating structure of tungsten-oxygen octahedral blocks. Furthermore, since all of the diffraction peaks were derived from the molecular film, it was confirmed that the resulting coating film contains the molecular film as the main component of the crystalline substance. (3) Heat treatment process Then, the substrate was heated under a gas containing 4% by volume of H2 gas with Ar gas as a carrier gas, and subjected to a reduction heat treatment at 700°C for 30 minutes. 11 O z The crystal orientation film according to Example 1 having a crystal orientation of (z<36) was obtained. The column for heat treatment conditions in Table 1 shows the heat treatment conditions in the heat treatment step.

[0136] The X-ray diffraction pattern of the crystal oriented film according to Example 1 was measured by in-plane X-ray diffraction using an X-ray diffractometer. Analysis of the X-ray diffraction pattern confirmed that the oxide thin film (oxide molecular film) that is the crystal oriented film according to Example 1 has a basic skeleton consisting of a repeating structure of tungsten-oxygen octahedral blocks. The peak positions of the X-ray diffraction pattern correspond to the Cs of hexagonal tungsten bronze. 0.9 The peak position coincided with that of W3O9 (ICDD 04-009-6455). This confirmed that the crystal oriented film of Example 1 was a hexagonal tungsten bronze, with a six-membered ring structure consisting of tungsten-oxygen octahedra and a one-dimensional tunnel structure. The crystal structure of the crystal oriented film is shown in the crystal structure column of Table 2.

[0137] Furthermore, when the diffraction planes were identified from the peak positions of the X-ray diffraction pattern, only the diffraction plane where l = 0 was confirmed when expressed in Miller indices hkl. Specifically, as shown in Figure 12, the hexagonal Cs 0.9Diffraction peaks originating from the (110), (200), (300), (220), (310), (400), (320), and (420) planes of W3O9 were confirmed. The diffraction peaks detected by in-plane X-ray diffraction are originating from planes perpendicular to the substrate or film surface. Therefore, for example, the (110) and (320) planes can be considered crystal planes perpendicular to the substrate or film surface, and the

[0001] crystal orientation parallel to the (110) and (320) planes was found to be perpendicular to the substrate or film surface. Since the

[0001] crystal orientation in hexagonal tungsten bronze is parallel to the one-dimensional tunnel structure, it was confirmed that the one-dimensional tunnel structure of the crystal-oriented film of Example 1 is perpendicular to the substrate or film surface. The column for the direction of the one-dimensional tunnel structure in Table 2 shows the relationship between the one-dimensional tunnel structure and the substrate or film surface.

[0138] Carbon was vapor-deposited on the crystalline oriented film of Example 1, and a cross-sectional thin section sample (thickness less than 100 nm) was prepared using a focused ion beam (FIB) processing device. Carbon was vapor-deposited as a protective film to prevent the crystalline oriented film from being damaged during processing. The cross-sectional thin section sample was then observed using a transmission electron microscope (JEOL JEM-ARM200F), and the transmission electron microscope image shown in FIG. 13 was obtained.

[0139] The crystalline oriented film 131 of Example 1 was observed in the obtained transmission electron microscope image. In FIG. 13, the crystalline oriented film 131 is located between a protective film 132 and a substrate (base material) 133. The protective film 132 is a carbon-deposited film and does not constitute a crystalline oriented film. The lattice fringes of hexagonal tungsten bronze, which are visible when observed at a

[0010] axis incidence, were confirmed in the crystalline oriented film, revealing that the one-dimensional tunnel structure of the crystalline oriented film is perpendicular to the film surface of the base material and the crystalline oriented film. Furthermore, before the heat treatment process, eight molecular films were stacked on top of each other, but they all reacted to form a single continuous film.

[0140] In addition, transmission electron microscope images were checked at multiple locations to determine the average film thickness. Furthermore, when crystallites were identified from lattice fringes, sheet-like crystallites were confirmed at every location. Therefore, the average length and thickness of the crystallites were determined.

[0141] The average film thickness was calculated by measuring the film thickness at 10 arbitrarily selected points in a cross-sectional image of the crystal orientation film taken by a transmission electron microscope, and averaging the measured film thickness values ​​at the 10 points.

[0142] The average crystallite length was calculated by measuring the maximum length of 10 arbitrarily selected crystallites along the film surface 62A (see Figure 6) in a cross-sectional image of the crystal-oriented film taken by a transmission electron microscope, and then calculating the average of the measured lengths of the 10 crystallites.

[0143] The thickness of the crystallites was measured at 10 measurement points spaced 50 nm apart from each other, and the average value of the measurements at the 10 points was calculated.

[0144] As a result, the film thickness was 15 nm, the average crystallite length was 1 μm, and the average crystallite thickness was 15 nm. The evaluation results are shown in the film thickness, crystallite length, and crystallite thickness columns in Table 2, respectively.

[0145] The crystal orientation film of Example 1 was analyzed by X-ray photoelectron spectroscopy (Ulvac-Phi XPS-Versa Probe III). 25 W Al-Kα X-rays were irradiated to measure excited photoelectrons, and the W4f spectrum observed in the vicinity of 30 to 45 eV was determined by peak fitting. 7 / 2 6+ , W4f 5 / 2 6+ , W4f 7 / 2 5+ , W4f 5 / 2 5+ , W5p 3 / 2 The peaks were separated into five. The ratio of W valences of 6+ and 5+ was calculated from the intensity area of ​​each peak. 6+ is 79.2%, W 5+The average valence of tungsten is calculated from this as follows: W 5.79+ In addition, the composition ratio of Cs and W was calculated to be Cs / W = 0.35. 0.35 WO z Assuming the composition formula is as follows, z was calculated to be 3.1. The results of the XPS evaluation are shown in the XPS column of Table 2.

[0146] Here, we will explain how to calculate z. Cs 0.35 WO z Assume that the charge is neutral. Since the valence of Cs is +1, considering the charge balance, 0.35 × 1 + (79.2 × 6 + 20.8 × 5) / 100 - 2 × z = 0. Solving this gives z = 3.1. The same calculation method was adopted in the following Example 2, Example 3, Comparative Example 1, Comparative Example 2, and Reference Example 1.

[0147] The transparency of the obtained crystal orientation film was evaluated using a spectrophotometer (UH4150 manufactured by Hitachi High-Tech Science Corporation). Transmitted light profiles and reflected light profiles were measured at 5 nm intervals in the wavelength range of 200 nm to 2600 nm. Visible light transmittance was calculated based on JIS R 3106 (2019) in the wavelength range of 380 nm to 780 nm, and was found to be 84%. Furthermore, in the near-infrared wavelength range of 780 nm to 2600 nm, the minimum transmittance was 55%, and the maximum reflectance was 13%. * a * b * The color index was calculated by first calculating the tristimulus values ​​X, Y, and Z for the D65 standard light source and a light source angle of 10° based on JIS Z 8701 (1999), and then calculating the tristimulus values ​​based on JIS Z 8729 (2004). * is 93, a * is 0.2, b * The optical property data obtained is shown in the spectroscopic measurement column of Table 2. The crystal orientation film obtained in this example has a visible light transmittance of 60% or more, a minimum transmittance of 70% or less in the near-infrared region, a maximum reflectance of 10% or more, and *0 or more. That is, it was confirmed that the crystalline orientation film according to Example 1 has excellent visible light transmittance and near-infrared shielding properties, and that blue coloration of the transmitted light is suppressed.

[0148] The mobility and carrier density of the obtained crystal orientation film were evaluated using a Hall effect measurement controller (M91 FastHall manufactured by Lake Shore). The mobility was 0.3 (cm 2 / (V s)), and the carrier density is 6.2 × 10 22 / cm 3 The crystal orientation film obtained in this example had a mobility of 0.01 (cm 2 / (V s)) or more, carrier density 1.0×10 19 / cm 3 The results are shown in the Hall effect measurement column in Table 2. [Example 2] A series of coating operations using the coating solution of Example 1 in the single droplet assembly method were repeated five times to form molecular film assemblies and laminated films of molecular film assemblies on the quartz substrate. The number of times the coating operation was repeated is shown in the column of the number of laminated layers in Table 1.

[0149] The X-ray diffraction patterns of the molecular film assemblies, which are coatings of molecular films formed on quartz substrates, and the molecular film assembly laminates were measured using in-plane X-ray diffraction with an X-ray diffractometer. Analysis of the X-ray diffraction patterns confirmed that all of the molecular film assemblies, which are coatings of molecular films, contain a molecular film with a pyrochlore crystal structure, with a basic skeleton consisting of a repeating structure of tungsten-oxygen octahedral blocks. Furthermore, since all of the diffraction peaks were derived from the molecular film, it was confirmed that all of the resulting coatings contained the molecular film as the main component of the crystalline substance. Note that the above coatings are molecular film assemblies, etc., after the coating process and before the heat treatment process.

[0150] A heat treatment process was carried out under the same conditions as in Example 1, except that the molecular film assembly and its laminate film according to Example 2 was used instead of the molecular film assembly and its laminate film according to Example 1, to produce a crystal oriented film according to Example 2, and the X-ray diffraction pattern was measured and analyzed in the same manner as in Example 1. As a result, it was confirmed that the oxide molecular film, which is the crystal oriented film according to Example 2, has a hexagonal tungsten bronze crystal structure and includes a six-membered ring structure consisting of tungsten-oxygen octahedra and a one-dimensional tunnel structure. It was also confirmed that the one-dimensional tunnel structure of the crystal oriented film according to Example 2 is perpendicular to the substrate and the film surface of the crystal oriented film.

[0151] Similar to Example 1, cross-sectional thin-section samples of the crystalline oriented film of Example 2 were prepared and observed using a transmission electron microscope. The transmission electron microscope image shown in FIG. 14 was obtained. From the transmission electron microscope image, it was confirmed that the crystalline oriented film of Example 2 all had a hexagonal tungsten bronze crystal structure, and contained a six-membered ring structure consisting of tungsten-oxygen octahedra and a one-dimensional tunnel structure. It was also revealed that the one-dimensional tunnel structure of the crystalline oriented film of Example 2 was perpendicular to the film surface of the crystalline oriented film. In FIG. 14, the crystalline oriented film 141 is located between a protective film 142 and a substrate 143.

[0152] Furthermore, in Example 2, five molecular films were stacked before the heat treatment step, but all of them reacted to form one continuous film.

[0153] The crystal structure, direction of the one-dimensional tunnel structure, film thickness, crystallite length, crystallite thickness, W valence ratio and composition, optical properties, mobility, and carrier density of the crystal orientation film of Example 2 were measured in the same manner as in Example 1. The evaluation results are shown in Table 2. [Example 3] A series of coating operations using the coating solution of Example 1 in the single droplet assembly method were repeated a total of 28 times to form molecular film assemblies and laminated films of molecular film assemblies on the quartz substrate. The number of times the coating operation was repeated is shown in the column of the number of laminated layers in Table 1.

[0154] The X-ray diffraction patterns of the molecular film assemblies, which are coatings of molecular films formed on quartz substrates, and the molecular film assembly laminates were measured using in-plane X-ray diffraction with an X-ray diffractometer. Analysis of the X-ray diffraction patterns confirmed that all of the molecular film assemblies, which are coatings of molecular films, contain a molecular film with a pyrochlore crystal structure, with a basic skeleton consisting of a repeating structure of tungsten-oxygen octahedral blocks. Furthermore, since all of the diffraction peaks were derived from the molecular film, it was confirmed that all of the resulting coatings contained the molecular film as the main component of the crystalline substance. Note that the above coatings are molecular film assemblies, etc., after the coating process and before the heat treatment process.

[0155] A heat treatment process was carried out under the same conditions as in Example 1, except that the molecular film assembly and its laminate film according to Example 3 were used instead of the molecular film assembly and its laminate film according to Example 1, to produce a crystal oriented film according to Example 3. The X-ray diffraction pattern of the crystal oriented film according to Example 3 was measured and analyzed in the same manner as in Example 1. As a result, it was confirmed that the oxide molecular film, which is the crystal oriented film according to Example 3, has a hexagonal tungsten bronze crystal structure and includes a six-membered ring structure consisting of tungsten-oxygen octahedra and a one-dimensional tunnel structure. It was also confirmed that the one-dimensional tunnel structure of the crystal oriented film according to Example 3 is perpendicular to the substrate and the film surface of the crystal oriented film.

[0156] Similar to Example 1, cross-sectional thin-section samples of the crystal-oriented film according to Example 3 were prepared and observed using a transmission electron microscope. As a result, it was confirmed that the crystal structure of each of the crystal-oriented films according to Example 3 was hexagonal tungsten bronze, and that it contained a six-membered ring structure consisting of tungsten-oxygen octahedra and a one-dimensional tunnel structure. It was also revealed that the one-dimensional tunnel structure of the crystal-oriented film according to Example 3 was perpendicular to the substrate and the film surface of the crystal-oriented film. In Example 3, 28 molecular films were stacked before the heat treatment process, but they all reacted to form a single continuous film.

[0157] The crystal structure, direction of the one-dimensional tunnel structure, film thickness, crystallite length, crystallite thickness, W valence ratio and composition, optical properties, mobility, and carrier density of the crystal orientation film of Example 3 were measured in the same manner as in Example 1. The evaluation results are shown in Table 2. [Comparative Example 1] A series of coating operations using the coating solution of Example 1 in the single droplet assembly method were repeated three times to form molecular film assemblies and laminated films of molecular film assemblies on the quartz substrate. The number of times the coating operations were repeated is shown in the column of the number of laminated layers in Table 1.

[0158] The X-ray diffraction patterns of the molecular film assemblies, which are coatings of molecular films formed on quartz substrates, and the molecular film assembly laminates were measured using in-plane X-ray diffraction with an X-ray diffractometer. Analysis of the X-ray diffraction patterns confirmed that all of the molecular film assemblies, which are coatings of molecular films, contain a molecular film with a pyrochlore crystal structure, with a basic skeleton consisting of a repeating structure of tungsten-oxygen octahedral blocks. Furthermore, since all of the diffraction peaks were derived from the molecular film, it was confirmed that all of the resulting coatings contained the molecular film as the main component of the crystalline substance. Note that the above coatings are molecular film assemblies, etc., after the coating process and before the heat treatment process.

[0159] A heat treatment process was carried out under the same conditions as in Example 1, except that the molecular film assembly of Comparative Example 1 was used instead of the molecular film assembly and its laminated film of Example 1, to produce a crystalline oriented material of Comparative Example 1. As in Example 1, the X-ray diffraction pattern of the crystalline oriented material of Comparative Example 1 was measured and analyzed. As a result, it was confirmed that the crystalline oriented material of Comparative Example 1 had a hexagonal tungsten bronze crystal structure, and contained a six-membered ring structure consisting of tungsten-oxygen octahedra and a one-dimensional tunnel structure, with the one-dimensional tunnel structure being perpendicular to the substrate.

[0160] A cross-sectional thin section sample of the crystalline oriented material according to Comparative Example 1 was prepared in the same manner as in Example 1. When the sample was observed using a transmission electron microscope, the transmission electron microscope image shown in FIG. 15 was obtained. It was found that the obtained crystalline oriented material 151 was not in the form of a film, but was composed of particles of several tens to several hundreds of nanometers distributed in an island-like pattern. In FIG. 15, the crystalline oriented material 151 is located between a protective film 152 and a substrate 153.

[0161] As in Example 1, an attempt was made to evaluate the mobility and carrier density of the oriented crystal material of Comparative Example 1 using a Hall effect measurement controller, but measurement was impossible due to high resistance. It was presumed that the conductive paths were not connected because the particles were distributed in an island-like manner. The evaluation results of the oriented crystal material according to Comparative Example 1 are shown in Table 2. Comparative Example 2 A molecular film assembly was formed on a quartz substrate by performing a series of coating operations using the single droplet assembly method only once using the coating solution of Example 1. The number of coating operations is shown in the column of the number of layers in Table 1.

[0162] The X-ray diffraction patterns of molecular film assemblies, which are coatings of molecular films formed on quartz substrates, were measured using in-plane X-ray diffraction with an X-ray diffractometer. Analysis of the X-ray diffraction patterns confirmed that all molecular film assemblies, which are coatings of molecular films, contain a molecular film with a pyrochlore crystal structure, whose basic structure is a repeating structure of tungsten-oxygen octahedral blocks. Furthermore, since all of the diffraction peaks were derived from the molecular film, it was confirmed that all of the resulting coatings contained the molecular film as the main component of the crystalline substance. Note that the above coatings are molecular film assemblies, etc., after the coating process and before the heat treatment process.

[0163] A heat treatment step was carried out under the same conditions as in Example 1, except that the molecular film assembly of Comparative Example 2 was used instead of the laminated film of the molecular film assembly of Example 1, to produce a crystalline oriented material of Comparative Example 2. As in Example 1, the X-ray diffraction pattern of the crystalline oriented material of Comparative Example 2 was measured and analyzed. As a result, it was confirmed that the crystalline oriented material of Comparative Example 2 had a hexagonal tungsten bronze crystal structure, and contained a six-membered ring structure consisting of tungsten-oxygen octahedra and a one-dimensional tunnel structure, with the one-dimensional tunnel structure being perpendicular to the substrate.

[0164] A cross-sectional thin section sample of the oriented crystal material according to Comparative Example 2 was prepared in the same manner as in Example 1. When observed with a transmission electron microscope, it was found that the oriented crystal material obtained was not in the form of a film, but was composed of particles of several tens to 100 nm distributed in an island shape.

[0165] Similar to Example 1, an attempt was made to evaluate the mobility and carrier density of the oriented crystal material of Comparative Example 2 using a Hall effect measurement controller, but measurement was impossible due to high resistance. It was presumed that the conductive paths were not connected because the particles were distributed in an island-like manner. The evaluation results of the oriented crystal material according to Comparative Example 2 are shown in Table 2. [Reference example 1] 10.2 g of cesium carbonate and 40.0 g of tungsten (VI) oxide were mixed so that the Cs:W molar ratio was 4:11, and the mixture was fired at 850°C for 5 hours in an air atmosphere. The powder X-ray diffraction pattern of the fired product indicated Cs4W. 11 O 35 The composition is shown in the composition column of the fired product in Table 1. 11 O 35 It was also confirmed that the compound has an orthorhombic crystal structure with a basic skeleton consisting of repeating tungsten-oxygen octahedral blocks.

[0166] The obtained Cs4W 11 O 350.5 g of the above was taken and added to 50 mL of 12 N hydrochloric acid, and the mixture was left at room temperature for 1 day, i.e., without heat treatment such as heating or cooling, and the mixture was mixed and stirred for an acid treatment. After removing the hydrochloric acid by decantation, the mixture was replaced with fresh hydrochloric acid and the same acid treatment was carried out for an additional 4 days (a total of 5 days of acid treatment), followed by filtration, washing with water, and air drying to recover the solid residue that was the acid treatment product (acid treatment step).

[0167] The Cs and W concentrations of the solid residue obtained were analyzed using an ICP optical emission spectrometer (Shimadzu Corporation, Model ICPE-9000), and were found to be 13 wt% and 66 wt%, respectively. Furthermore, the chemical formula was calculated from the results, and it was confirmed that the solid residue had a molar ratio of Cs / W = 3 / 11. The analytical results of the above hydrogen-type substance, which was the solid residue obtained after the acid treatment process, are shown in the hydrogen-type substance column in Table 1.

[0168] 0.4 g of the resulting solid residue was added to 100 cm of a 0.0016 mol / L aqueous solution of tetrabutylammonium hydroxide. 3 The mixture was stirred at 200 rpm for 7 days, and then the precipitated components were removed by centrifugation. 11 O 35 - A dispersion containing a molecular film of the above was obtained (colloidization step). Here, the molecular film was obtained in a negatively charged state, but the surface of the molecular film was charged with tetrabutylammonium ions (TBA + It is thought that the overall state is close to neutral.

[0169] The obtained Cs3W 11 O 35 - A dispersion containing the molecular film was dropped onto a microgrid for observation of transmission electron microscope images, and the molecular film was transferred and observed by transmission electron microscope. For the 10 molecular films observed for morphology, it was confirmed that the average longitudinal length of the molecular film was 5 μm. Furthermore, analysis of the crystal structure from the electron diffraction pattern of the molecular film revealed that the obtained molecular film was the same as that of Cs4W before acid treatment. 11 O 35As in the previous study, it was confirmed that the molecular film has a basic skeleton consisting of a repeating structure of tungsten-oxygen octahedral blocks.

[0170] The obtained Cs3W 11 O 35 - 0.1 mL of the dispersion containing the molecular film, 5.0 mL of pure water, and 0.03 mL of ethanol were mixed to prepare a coating liquid according to Reference Example 1. (2) Coating process The coating operation was carried out by the single droplet accumulation method using the coating solution according to Example 1. After heating the quartz substrate, which was the base material, to a temperature of 120°C on a hot plate, the coating solution according to Example 1 was dropped onto the base material, and then the supplied coating solution was slowly sucked up with a pipette to form a Cs3W 11 O 35 - A molecular film assembly composed of these was fabricated on a quartz substrate, and then dried at 200°C for 3 minutes to adhere the molecular film assembly to the quartz substrate.

[0171] The series of coating steps using the single droplet assembly method was repeated a total of eight times to stack molecular film assemblies. This resulted in eight molecular films and molecular film assemblies stacked together, i.e., an eight-layer stack. The number of times the coating steps were repeated is shown in the "Number of Layers" column in Table 1.

[0172] The X-ray diffraction pattern of the molecular film assembly, which is a coating film of a molecular film formed on a quartz substrate, was measured by in-plane X-ray diffraction using an X-ray diffractometer. Analysis of the X-ray diffraction pattern confirmed that the molecular film assembly contains a molecular film with an orthorhombic crystal structure whose basic skeleton is a repeating structure of tungsten-oxygen octahedral blocks. Furthermore, since all of the diffraction peaks were derived from the molecular film, it was confirmed that the resulting coating film contains the molecular film as the main component of the crystalline substance. (3) Heat treatment process Then, the substrate was heated under a gas containing 4% H2 gas by volume with Ar gas as a carrier gas, and a reduction heat treatment was performed at 600°C for 180 minutes, resulting in the deposition of Cs3W on one side of the substrate. 11 O zA crystal oriented film having a crystal orientation of (z<35) was obtained according to Reference Example 1. The column for heat treatment step conditions in Table 1 shows the heat treatment conditions in the heat treatment step.

[0173] The X-ray diffraction pattern of the crystal oriented film according to Reference Example 1 was measured by in-plane X-ray diffraction using an X-ray diffractometer. Analysis of the X-ray diffraction pattern confirmed that the oxide thin film (oxide molecular film) that is the crystal oriented film according to Reference Example 1 has a basic skeleton consisting of a repeating structure of tungsten-oxygen octahedral blocks. Furthermore, the peak positions of the X-ray diffraction pattern were determined to be those of hexagonal Cs 0.9 Since the peak position coincided with that of W3O9 (ICDD 04-009-6455), it was confirmed that the crystal oriented film of Example 1 had a hexagonal crystal structure.

[0174] Furthermore, when the diffraction planes were identified from the peak positions in the X-ray diffraction pattern, only diffraction planes where h and k are the same when expressed using Miller indices hkl were confirmed. Specifically, as shown in Figure 16, diffraction peaks were confirmed from the (002), (110), (111), (112), (113), (004), (220), (222), (224), (006), and (331) planes. The diffraction peaks detected by in-plane X-ray diffraction are from planes perpendicular to the substrate or film surface. Therefore, for example, the (002) and (004) planes can be said to be crystal planes perpendicular to the substrate or film surface. This indicates that the

[0001] crystal orientation perpendicular to the (002) and (004) planes is parallel to the substrate or film surface. In addition, the (110) and (220) planes can be said to be crystal planes perpendicular to the substrate or film surface, and this indicates that the

[0110] crystal orientation perpendicular to the (110) and (220) planes is parallel to the substrate or film surface. Furthermore, the [-110] crystal orientation perpendicular to both the

[0001] and

[0110] crystal orientations is perpendicular to the substrate or film surface.

[0175] Carbon was vapor-deposited on the crystal-oriented film of Reference Example 1, and a cross-sectional thin section sample was prepared using a focused ion beam (FIB) processing device. Carbon was vapor-deposited as a protective film to protect the crystal-oriented film from damage during processing. Observation of the cross-sectional thin section sample using a transmission electron microscope confirmed the lattice fringes of hexagonal tungsten bronze, which are visible when observed with the 0001 axis incident. Specifically, it was revealed that the crystal-oriented film of Reference Example 1 contains a six-membered ring structure consisting of tungsten-oxygen octahedra and a one-dimensional tunnel structure, with the one-dimensional tunnel structure being parallel to the substrate and the film surface of the crystal-oriented film. Furthermore, prior to the heat treatment process, eight molecular films were stacked on top of each other, but all of them reacted to form a single continuous film. The crystal structure, direction of the one-dimensional tunnel structure, film thickness, crystallite length, crystallite thickness, W valence ratio and composition, optical properties, mobility, and carrier density of the crystal orientation film of Reference Example 1 were measured in the same manner as in Example 1. The evaluation results are shown in Table 2.

[0176] The crystalline oriented films obtained in Examples 1 to 3 have a visible light transmittance of 60% or more, a minimum transmittance of 70% or less in the near-infrared region, a maximum reflectance of 10% or more, and * 0 or more. That is, it was confirmed that the crystal orientation films obtained in Examples 1 to 3 have excellent visible light transmittance and near-infrared shielding properties, and that the blue coloration of the transmitted light is suppressed. In addition, the mobility was 0.01 (cm 2 / (V s)) or more, carrier density 1.0×10 19 / cm 3 As mentioned above, it was confirmed that the film had excellent electrical properties, i.e., it was found that both optical and electrical properties were achieved.

[0177] It was also confirmed that the carrier density of the crystal orientation films according to Examples 1 to 3 was higher than that of Reference Example 1, and that they had excellent electrical properties. * was 0 or more, and it was confirmed that the blue coloring of the transmitted light was suppressed more than in Reference Example 1. [Table 1] [Table 2] [Explanation of symbols]

[0178] 11 Tungsten-Oxygen Octahedral Block 11A Six-membered ring structure 12 One-dimensional tunnel structure 13 M 60 Crystal-oriented film with substrate 61 Base material 61A One side 61B The other side 621 Crystal 622 Crystal 623 Crystallite 62 Crystal Orientation Film 62A Membrane surface 70 Structure 80 structure 90 Structure 100 structures 110 Structure 71 Matrix 91 Base material 111 Conductive particles 131 Crystal Orientation Film 132 Protective film 133 PCB 141 Crystal Orientation Film 142 Protective film 143 PCB 151 Crystal orientation 152 Protective film 153 PCB

Claims

1. A crystal orientation film, It contains a six-membered ring structure and a one-dimensional tunnel structure made of tungsten-oxygen octahedral blocks, A crystalline orientation film in which the one-dimensional tunnel structure is oriented in a direction perpendicular to the film surface of the crystalline orientation film.

2. General formula M ｘ W ｙ O ｚ (However, M is H, Li, Na, K, Rb, Cs, Be, Mg, Ca, Sr, Ba, Sc, Y, La, Ce, Pr, Nd, Pm , Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, Mn, Element group including Re, Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, In, Tl, C, Si, Ge, Sn, Pb, N, P, As, Sb, Bi, S, Se, Te, F, Cl, Br, I, and H ２ O, H ３ O, N.H. ４ 2. The crystalline oriented film according to claim 1, comprising a composite tungsten oxide represented by the formula: (x / y)=1, 2.0≦z / y≦3.5, where W is tungsten, O is oxygen, and 0.001≦x / y≦1, 2.0≦z / y≦3.

5.

3. 3. The crystalline oriented film according to claim 2, wherein M includes one or more elements selected from the group consisting of H, Li, Na, K, Rb, Cs, Ca, Sr, Ba, Fe, Cu, Ag, In, Tl, Sn, Pb, and Yb.

4. The oriented crystal film according to claim 2 , wherein the M includes at least one element selected from the group consisting of Cs and Rb.

5. 3. The crystalline oriented film according to claim 1, comprising crystals having any one of a hexagonal, monoclinic, and orthorhombic crystal structure.

6. 3. The crystalline oriented film according to claim 1, comprising crystals having a hexagonal crystal structure.

7. Mobility is 0.01 cm ２ / (V・s) or more 1000cm ２ 3. The crystalline oriented film according to claim 1, wherein the axial tension is 1 / (V·s) or less.

8. Carrier density is 1.0 × 10 １９ / cm ３ Above 1.0 x 10 ２４ / cm ３ 3. The crystalline oriented film according to claim 1, wherein:

9. 3. The crystalline oriented film according to claim 1, wherein the average length of the crystallites contained in the crystalline oriented film along the film surface is 100 nm or more.

10. A structure comprising the crystal orientation film according to claim 1 or 2.

11. a molecular film formation step of producing a molecular film containing tungsten as an element; a coating step of coating the molecular film on a substrate; and a heat treatment step of heat treating the molecular film coated on the substrate at a temperature of 650° C. or higher and 750° C. or lower in a reducing atmosphere.

12. The method for producing a crystal oriented film according to claim 11 , wherein the number of layers of the molecular film is 5 or more in the coating step.

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