JP4849375B2 - Fine particle array thin film, method for manufacturing the same, and fine particle array thin film manufacturing apparatus - Google Patents

Description

  The present invention relates to a fine particle array thin film and a method for manufacturing the same, and a fine particle array thin film manufacturing apparatus. More specifically, the present invention relates to a fine particle array thin film in which monodisperse fine particles are regularly arranged three-dimensionally, a method for manufacturing the same. The present invention relates to a fine particle array thin film manufacturing apparatus for manufacturing such a fine particle array thin film.

A structure in which monodispersed fine particles (colloidal particles) having a diameter of about 50 nm to 1 μm are regularly arranged in a three-dimensional manner is called a “colloidal crystal” compared with a crystal in which atoms and molecules are regularly arranged in a three-dimensional manner. There are colloidal crystals in which fine particles are regularly arranged in a liquid and the fine particles are not in contact with each other and in which the fine particles are in contact with each other. The latter is particularly called “artificial opal”.
Further, when a colloidal crystal is used as a template and another substance is embedded in the void and the fine particles are removed, a structure in which pores corresponding to the size of the fine particles are regularly arranged in three dimensions is obtained. Such a structure is generally called “inverse opal”.

  Since the colloidal crystal has a periodicity as long as the wavelength of light, it has the property of Bragg-reflecting light of a specific wavelength. For this reason, colloidal crystals are expected to be applied to optical elements and sensors such as narrow band filters. Inverse opal produced using colloidal crystals as a template is considered to be one of candidate materials for photonic crystals that are expected to be applied as high-efficiency optical transmission lines or high-efficiency light-emitting elements.

  The interaction acting between the fine particles dispersed in an appropriate dispersion medium is represented by the sum of the electrostatic repulsive force generated by the electric potential distribution on the fine particle surface and the attractive force due to the van der Waals force. Therefore, in order to disperse the particles in the dispersion medium and to regularly arrange the fine particles, the electrostatic force acting between the fine particles needs to be well controlled. As a method for obtaining a colloidal crystal by regularly arranging fine particles, the following methods are specifically known.

  For example, Patent Document 1 discloses that a cell is formed by stacking two plates each having a recess inside and whose inner surfaces are flat and parallel to each other, and polystyrene spheres are dispersed in the cell recess. A filter device obtained by injecting an aqueous solution, sealing the cell and leaving it at room temperature is disclosed. In this document, the lattice constant of a colloidal crystal is changed by controlling the temperature of the cell and / or the external electric field applied to the cell, and thereby the wavelength for Bragg reflection can be varied, and the concentration of polystyrene spheres increases. The point that the lattice constant of the colloidal crystal is reduced is described.

  Non-Patent Document 1 discloses a method for producing a colloidal crystal in which a hydrophilic glass substrate is vertically immersed in a colloid solution and the glass substrate is pulled up at a constant speed. In this document, the film thickness can be controlled by controlling the particle concentration in the colloid solution and / or the pulling speed, and the colloidal crystal obtained by such a method has an interval of 10 μm to 100 μm. The point where the crack has occurred is indicated.

Patent Document 2 discloses a container in which a spacer is provided around a flat upper support, a lower support having a predetermined uneven pattern formed on the surface thereof, and an opening is formed at one end thereof, and the container. A method for producing an artificial crystal is disclosed in which an opening is held obliquely, a colloidal solution is injected from the opening, and a solvent component is evaporated from the opening. In the same document,
(1) When the colloid solution is injected from the opening, the colloid solution penetrates into the gap between the inner surface of the upper support and the convex portion of the lower support by capillary action,
(2) After several hours in this state, the fine particles settle down under the action of gravity, colloidal crystals are formed at the bottom,
(3) It is described that the solvent component slowly evaporates from the opening, and the solvent component can be completely evaporated without destroying the colloidal crystal.

  Patent Document 3 discloses an artificial crystal body in which a gap module having a gap formed by two supports so as to have openings at least in the vertical direction is immersed in a colloidal solution, and the gap module is pulled upward. A manufacturing method is disclosed. In this document, an artificial crystal in which silica particles are regularly arranged in a face-centered cubic structure is obtained by immersing the gap module in a colloidal silica solution, lifting the gap module at a pulling rate of 1 μm per second, and drying for 12 hours. Points are listed.

Further, in Non-Patent Document 2, a packing cell in which a rectangular gasket (resin film hollowed out inside) is sandwiched between two glass substrates and an injection tube is provided in the center of the upper glass plate, and this packing A method for producing a colloidal crystal in which a colloidal solution is injected from a cell injection tube and ultrasonic vibration is applied to the packing cell is disclosed. In this document, various methods are used to form a groove narrower than the diameter of the colloidal particles between the resin film and the glass substrate, and when ultrasonic vibration is applied to the packing cell, the solvent flows out of the groove, and between the glass substrates. Describes that a colloidal crystal can be formed, and that a crack is generated in the colloidal crystal by drying and is divided into domains of about 100 × 100 μm ² .

U.S. Pat. No. 4,632,517 JP 2003-201198 A JP 2003-201194 A Z.-Z. Gu et al., Chem. Mate. 14 (2002) 760 Y. Lu et al., Langmuir 17 (2001) 6344

  The filter device disclosed in Patent Document 1 exhibits excellent optical filter characteristics. However, since this is a regular arrangement structure in the liquid, if the liquid is not completely sealed, there is a disadvantage that the liquid evaporates and the filter characteristics change. Further, when a strong impact is applied to the cell, there is a drawback that the structure of the colloidal crystal formed in the liquid is easily broken.

  Further, the pulling method disclosed in Non-Patent Document 1 is a method in which a substrate having good affinity for fine particles is inserted vertically (or may be inclined) into the fine particle dispersion, and then the substrate is slowly pulled up to an appropriate amount. The fine particle dispersion is transferred to the surface of the substrate, and then the particles are self-ordered in the process of evaporation of the dispersion medium from the transferred fine particle dispersion. In this method, since the pulling direction is unidirectional, the crystal orientation of the obtained film is relatively uniform, and it is said that an ordered array thin film close to a single crystal state can be obtained.

However, if the fine particle solution in which the fine particles are dispersed is allowed to stand, the fine particles in the dispersion gradually settle. Therefore, in the case of preparing a regular array thin film by the pulling method, the larger the particle size of the fine particles contained in the dispersion (> 400 nm), the easier the fine particles settle during the pulling, and the fine particles having a uniform film thickness. Fabrication of the arrayed thin film becomes difficult.
The pulling method is a method of forming an arrayed thin film by immersing the substrate in a container such as a beaker. Therefore, although it depends on the size of the substrate, it requires at least several tens of ml of dispersion. It is common. Moreover, it is necessary to pull up the immersed substrate at a low speed of 0.1 μm / sec to 10 μm / sec, and a complicated apparatus such as computer control is required.

  Furthermore, since the dispersion medium gradually evaporates during the pulling up, the concentration of the dispersion changes and the film thickness changes in the early and late stages of the formation of the array film. This film thickness non-uniformity can be controlled by changing the pulling speed between the initial stage and the later stage of film formation, but the process becomes more complicated. In addition, the crystal orientation shifts due to the shape of the interface between the substrate and the dispersion and the gas phase (meniscus), and it is difficult to obtain a single crystal plane on the entire substrate surface, and the drying of the dispersion near the meniscus is abrupt. There are also problems such as the occurrence of cracks because they occur.

  On the other hand, the methods disclosed in Patent Documents 2 and 3 and Non-Patent Document 1 are all methods for forming a fine particle array thin film using a physical confinement effect. However, the method disclosed in Patent Document 3 basically has the same problem as the pulling method described above.

  Further, the method disclosed in Patent Document 2 is a method for obtaining a fine particle array structure having a fine special shape, and the fine particle dispersion cannot be replenished. Therefore, it is difficult to obtain a large area thin film by this method. In addition, the solvent in the fine particle dispersion that has permeated into the gap between the inner surface of the upper support and the convex portion of the lower support volatilizes from the periphery of the gap and passes through the gap between the recess and the spacer. Evaporates from the opening. That is, the solvent in the fine particle dispersion between the inner surface of the upper support and the convex portion of the lower support flows in a two-dimensional direction. Therefore, even if this method is applied to a large area thin film, a crack occurs in the thin film during drying, and a sound large area thin film cannot be obtained.

  Furthermore, the method disclosed in Non-Patent Document 2 needs to form a groove having a width smaller than the particle diameter of the colloidal particles between the glass substrate and the gasket, and requires a complicated process such as photolithography. To do. In addition, since the solvent in the fine particle dispersion held in the voids flows in a two-dimensional direction, cracks are generated in the thin film during drying, and a sound large-area thin film cannot be obtained. Furthermore, in order to obtain an array structure by this method, it is necessary to apply a driving force such as ultrasonic vibration to the packing cell.

The problem to be solved by the present invention is a fine particle array thin film that is resistant to vibration and has no characteristic change due to liquid leakage, a method for manufacturing the same, and a fine particle array thin film manufacturing apparatus capable of producing such a fine particle array thin film. It is to provide.
Another problem to be solved by the present invention is a fine particle array thin film having a uniform crystal orientation in the film plane, few cracks and a large area, a method for producing the same, and such a fine particle array. An object of the present invention is to provide a fine particle array thin film manufacturing apparatus capable of manufacturing a body thin film.
Furthermore, another problem to be solved by the present invention is to produce a fine particle array thin film capable of producing a large particle array thin film from a small amount of fine particle dispersion without using a complicated apparatus or process. The object is to provide a method and a fine particle array thin film manufacturing apparatus.

Particle array film according to the present invention in order to solve the above problems, comprises a thin film monodisperse particles are regularly arranged, have a crystal orientation uniform periodic structure of the film surface, the area ratio of cracks There Ri der than 8%, and the magnitude of the thin film is summarized as a this is 45 mm × 20 mm or more.
Further, fine particle arrangement thin film manufacturing apparatus according to the present invention, one is the upper surface side, so the other is a lower surface side, two flat plate-like support which face each other with a spacing of Jo Tokoro, two said At least both ends of the flat plate support are sealed, a gap is formed between the two flat plate supports, and a first opening is formed at the tip of the two flat plate supports. And a reservoir for holding a fine particle dispersion in which monodisperse fine particles are dispersed, provided on the rear end side of the two flat plate-like supports. And
Furthermore, the method for producing a fine particle array thin film according to the present invention is a method using the fine particle array thin film production apparatus according to the present invention, wherein an injection step of injecting the fine particle dispersion into the reservoir portion, And an arranging step of arranging the monodispersed fine particles in the void.

  In the present invention, the driving force for obtaining a regular array structure (close-packed structure) is the flow of the dispersion generated in the voids as the dispersion medium in the dispersion evaporates from the openings. That is, when both ends of the two plate-like supports are sealed and the fine particle dispersion is injected into a liquid reservoir provided on the rear end side, the space is filled with the fine particle dispersion. Next, as the dispersion medium gradually evaporates from the opening at the front end, a one-way flow from the rear end side toward the first opening at the front end side is generated in the dispersion liquid in the gap. Due to this flow, the fine particles are carried to the first opening and regularly deposited in the vicinity of the first opening. Further, since the fine particle dispersion liquid is replenished from the liquid reservoir portion, the fine particles are regularly deposited in the entire void portion.

  In the present invention, since the flow of the dispersion liquid is aligned in one direction, an array body in a single crystal state in which the crystal orientation is aligned in the film plane is obtained. Moreover, since the drying location is limited, drying proceeds very slowly. Therefore, the frequency of cracks that occur during drying is significantly reduced. Further, since the fine particle dispersion is appropriately replenished in the voids, a large-area thin film can be obtained from an extremely small amount of the dispersion. Furthermore, since the fine particle array thin film according to the present invention has a crystal state close to a single crystal and has an extremely low crack density, it exhibits excellent optical characteristics such as high wavelength selectivity and high reflectance.

Hereinafter, an embodiment of the present invention will be described in detail.
The fine particle array thin film according to the first embodiment of the present invention includes a thin film in which monodispersed fine particles are regularly arranged, has a periodic structure in which crystal orientations in the film surface are aligned, and has a crack area. The rate is 8% or less.

In the present invention, “monodispersed fine particles” refers to those having a particle size variation represented by the following formula (1) of 10% or less. If the variation in particle diameter exceeds 10%, it becomes difficult to regularly arrange the fine particles. In order to obtain a fine particle array thin film that is close to a single crystal state, the smaller the variation in particle diameter, the better.
Variation in particle diameter (%) = σ × 100 / d _mean (1)
However, (sigma) is a standard deviation and _dmean is an average particle diameter. The standard deviation σ is expressed by the following equation (2). The standard deviation σ and the average particle diameter d _mean are respectively determined by measuring the particle size distribution of the fine particles. As the particle size distribution measurement method, there are (1) an image method in which a large number of particles are directly observed by SEM or TEM, (2) a static light scattering method, and (3) a dynamic light scattering method.

  The average particle size of the monodispersed fine particles is not particularly limited, and any monodispersed particles that can form at least a stable colloidal solution may be used. In order to form a stable colloidal solution, the average particle size of the monodisperse fine particles is preferably 5 nm to 2 μm. Generally, when the average particle size of monodispersed fine particles changes, the optical characteristics of the fine particle array thin film change. Accordingly, the average particle size of the monodispersed fine particles is selected in accordance with the use of the fine particle array thin film, the required characteristics, and the like.

The material of the monodispersed fine particles is not particularly limited, and various materials can be used. Generally, when the material (in particular, refractive index) of monodispersed fine particles changes, the optical characteristics of the fine particle array thin film change. Accordingly, the material of the monodisperse fine particles is selected in accordance with the use of the fine particle array thin film, the required characteristics, and the like.
As monodisperse fine particles, specifically,
(1) Ceramic particles such as silica fine particles,
(2) Polymer particles such as polystyrene fine particles, polymethyl methacrylate (PMMA),
(3) The surface of the core made of ceramic particles, polymer particles, etc. is coated with a shell made of a material different from the core (for example, metal fine particles, metal oxide fine particles such as titania, metal oxide nanosheets such as titania). Core / shell particles,
(4) Hollow-type particles obtained by removing the core from the core / shell-type particles using a method such as firing or extraction,
and so on.

The fine particle array thin film may be a single layer film in which only one monodispersed fine particle is regularly arranged (a structure in which monodispersed fine particles are two-dimensionally ordered), or such a monolayer film. May be a multilayer film (a structure in which monodisperse fine particles are regularly arranged in a three-dimensional manner) in which a plurality of layers are regularly stacked in the film thickness direction.
The number of monolayer films in the fine particle array thin film changes the average particle diameter of the monodispersed fine particles and the height of the voids (interval between two parallel flat plates) of the fine particle array thin film manufacturing apparatus described later. Therefore, it can be arbitrarily controlled.
Similarly, the film thickness of the fine particle array thin film can be arbitrarily controlled by changing the height of the gap of the fine particle array thin film manufacturing apparatus described later. The thickness of the fine particle array thin film is not particularly limited, but is preferably 0.2 mm or less. This is because if the thickness is too large, the fine particle dispersion liquid flows out (or leaks) from the opening, making it difficult to hold the dispersion liquid inside the gap and form a fine particle array thin film. is there.

The area of the fine particle array thin film can be arbitrarily controlled by changing the area of the flat support of the fine particle array thin film manufacturing apparatus described later. When a fine particle array thin film manufacturing apparatus described later is used, a fine particle array thin film having a relatively large area (specifically, 10 cm ² or more) can be produced from an extremely small amount of the fine particle dispersion.

The “periodic structure in which the crystal orientations in the film plane are aligned” means that there is almost no crystal grain boundary and is almost in the same state as a single crystal. Specifically, it means that in an area of 90% or more of the entire film surface, the diffraction pattern measured from the direction perpendicular to the film surface shows a spot pattern, and the arrangement direction of the spots is within ± 5 °.
In principle, the diffraction pattern is measured by irradiating a laser beam perpendicularly to the film and observing the transmitted light on a screen placed behind the sample. However, if it is not possible in principle to observe the diffraction pattern with the laser beam due to the relationship between the particle diameter and the wavelength of the laser beam, two-dimensional Fourier transform is performed on the particle array of the scanning electron microscope (SEM) image. The pattern obtained by the above may be substituted.

The “area ratio of cracks” refers to the percentage of the total area of cracks included in the 200 μm × 300 μm region (the ratio of the crack area per unit area). Generally, in order to improve the optical characteristics of the fine particle array thin film, the smaller the crack area ratio, the better. When using the fine particle array thin film manufacturing apparatus described later, the fine particle array thin film has a crack area ratio of 8% or less, and if the manufacturing conditions are optimized, the crack area ratio is 2% or less, or 1% or less. Even a fine particle array thin film can be manufactured.
Furthermore, if the manufacturing conditions are optimized, it is possible to manufacture even a fine particle array thin film in which the area of the area where the crack area ratio is not more than the above-described value is 90% or more of the entire film surface.

  In order to improve the optical characteristics of the fine particle array thin film, the width of the crack is preferably as narrow as possible. When a microparticle array thin film manufacturing apparatus described later is used, a microparticle array thin film having a crack width of 4 times or less the average particle diameter of monodispersed microparticles can be obtained. In addition, if the manufacturing conditions are optimized, a fine particle array thin film having a crack width of 3 times or less, 2 times or less, 1 time or less, or 0.5 times or less the average particle diameter of monodispersed fine particles can be obtained. .

In the present invention, the regularly arranged monodisperse fine particles are in contact with any one or more of the adjacent monodisperse fine particles. The regular arrangement structure of the monodisperse fine particles is not particularly limited, and can take various structures such as a face-centered cubic structure, a hexagonal close-packed structure (closest packed structure), a body-centered cubic structure, a simple cubic structure, and the like. .
Among these, the regularly arranged structure of monodisperse fine particles is preferably a (111) -oriented face-centered cubic structure or a hexagonal close-packed structure in the film thickness direction. When a fine particle array thin film manufacturing apparatus according to the present invention described later is used, a fine particle array thin film in which fine particles are closely packed in the film thickness direction can be easily manufactured.

Further, the gaps between the monodispersed fine particles that are in contact with each other may be filled with gas, liquid, or a solid made of a material different from the monodispersed fine particles. In general, since the refractive index of gas is smaller than that of liquid or solid, the effective refractive index of the fine particle array thin film can be arbitrarily controlled by appropriately selecting the material to be filled in the gaps between the monodisperse fine particles. .
Specific examples of the gas filled in the gaps between the monodisperse fine particles include air.
Specifically, the liquid to be filled between the monodispersed fine particles includes (1) water, (2) an organic solvent such as alcohol, ether and ester, (3) a cationic component such as imidazolium salt and pyridinium salt, and BF. ionic liquids consisting of anionic components ⁴ and ^{PF 6-,} etc. (ambient temperature molten salt), and the like.
Specific examples of the solid filled between the monodisperse fine particles include (1) polymers such as acrylic (polyacrylic acid ester), polystyrene, fluororesin, and silicone resin, and (2) TiO ₂ , Al ₂ O ₃ , Si _There are ceramics such as ₃ N ₄ and SiO ₂ and (3) semiconductors such as Si and Ge.
Furthermore, the monodispersed fine particles may be filled with only one of the above-described gas, liquid, or solid, or may be filled with two or more.

When at least one of gas and liquid is filled in the gaps between the monodisperse fine particles, one surface or both surfaces of the fine particle array thin film must be supported by a flat plate-like support. In addition, if necessary, both surfaces of the fine particle array thin film may be supported by two flat support members and the periphery thereof may be sealed. On the other hand, when the solid is filled in the gaps between the monodisperse fine particles, the fine particle array thin film is a self-supporting film, and thus a flat plate-like support is not always necessary.
The material of the flat support is not particularly limited as long as it does not adversely affect the optical characteristics of the fine particle array thin film, and can be arbitrarily selected according to the use of the fine particle array thin film, required characteristics, and the like. For example, when the fine particle array thin film according to the present invention is used as an optical filter that transmits only light of a specific wavelength included in incident light, the flat support is made of a material that transmits at least light of a specific wavelength. It is preferable to use it. On the other hand, when both surfaces of the fine particle array thin film are supported by a flat support, when using reflection characteristics, at least one of the flat supports may be a material that transmits light of a specific wavelength. .
Specific examples of the material of the flat support include (1) glass, (2) Si wafer, (3) metal plate such as iron, stainless steel, and aluminum.

Next, the fine particle array thin film according to the second embodiment of the present invention will be described. The fine particle array thin film according to the present embodiment has a so-called “reverse opal” structure, and includes a thin film in which monodispersed fine particles are regularly arranged, and has a periodic structure in which crystal orientations are aligned in the film plane. It is obtained by removing the monodisperse fine particles from the fine particle array thin film in which the area ratio of cracks is 8% or less and the monodispersed fine particles are filled with a solid different from the monodispersed fine particles.
Other points regarding the fine particle array thin film such as “monodisperse fine particles”, “periodic structure”, “crack area ratio”, “solid” and the like are the same as those in the first embodiment, and thus the description thereof is omitted. To do. A method for removing monodisperse fine particles will be described later.

Next, the fine particle array thin film manufacturing apparatus according to the present invention will be described.
FIG. 1 shows a schematic configuration diagram of a fine particle array thin film manufacturing apparatus. In FIG. 1, the fine particle array thin film manufacturing apparatus 10 includes flat plate supports 12 a and 12 b, spacers (first spacers) 14 a and 14 b, and a liquid reservoir 16. The two flat plate supports 12a and 12b are opposed to each other with a predetermined interval, and both ends thereof are sealed by a pair of spacers 14a and 14b inserted between the flat plate supports 12a and 12b. Yes. The spacers 14a and 14b are for forming a gap 18a having a predetermined height and width between two flat plate-like supports. In addition, a first opening 18b is formed on the front end side of the plate-like supports 12a and 12b sealed at both ends by the spacers 14a and 14b. The first opening 18b is for volatilizing the dispersion medium contained in the fine particle dispersion filled in the gap 18a.

The liquid reservoir 16 is for holding a fine particle dispersion in which monodisperse fine particles are dispersed, and for replenishing the void portion 18a with the fine particle dispersion. In order to generate a unidirectional flow in the fine particle dispersion filled in the gap 18a, the liquid reservoir 16 is provided on the rear end side (that is, the first opening) of the two plate-like supports 12a and 12b. It is necessary to provide it on the side opposite to the portion 18b.
The structure of the liquid reservoir 16 is not particularly limited, and the fine particle dispersion can be replenished in the void 18a, and a one-way flow can be generated in the fine particle dispersion in the void 18a. Anything is possible. For example, by replacing the pair of spacers 14a and 14b with U-shaped spacers, or by inserting a third spacer on the rear end side of the plate-like supports 12a and 12b, etc. The rear ends of the supports 12a and 12b may be sealed, and a cylindrical or rectangular liquid reservoir may be provided on the rear end of the upper surface of the flat support 12b.

  In the example shown in FIG. 1, the liquid reservoir 16 supplies the fine particle dispersion to the gap 18 a from the second opening 18 c formed at the rear ends of the two flat supports 12 a and 12 b. ing. That is, the flat plate-like support body 12a on the lower surface side is longer than the flat plate-shaped support body 12b on the upper surface side. An upper cover 20 is provided above a portion extended to the rear end side of the flat support 12a. The extension on the rear end side of the flat support 12a, both ends of the upper cover 20, and the end face on the rear end side of the flat support 12b are sealed with second spacers 22a and 22b. The liquid reservoir 16 includes a rear end extension of the flat support 12a, the upper cover 20, and the second spacers 22a and 22b, and the fine particle dispersion is held in a space surrounded by these. When the liquid reservoir 16 is connected to the second opening 18c, there is an advantage that the fine particle array thin film can be formed in the entire gap 18a.

The thickness of the first spacers 14a and 14b may be any thickness that allows the fine particle dispersion to enter the gap 18a by capillary action. By changing the thickness of the first spacers 14a and 14b, the distance between the two flat plate-like supports 12a and 12b (that is, the thickness of the fine particle array thin film formed in the void 18a) can be changed. it can.
However, the thickness of the first spacers 14a and 14b is preferably larger than the average particle diameter of the monodispersed fine particles contained in the fine particle dispersion. In order to obtain a fine particle array thin film in which a plurality of monodispersed fine particles are laminated, the thickness of the first spacers 14a and 14b is preferably larger than twice the average particle size of the monodispersed fine particles.
On the other hand, the thickness of the first spacers 14a and 14b is preferably 0.2 mm or less. When the thickness of the first spacers 14a and 14b exceeds 0.2 mm, the fine particle dispersion liquid flows out (or leaks) from the first opening 18b, and the fine particle array body holds the dispersion liquid inside the gap. Since it becomes difficult to form a thin film, it is not preferable.

The thickness of the second spacers 22a and 22b is not particularly limited, and an optimal one is selected according to the shape of the upper cover 20, the volume of the fine particle dispersion held in the liquid reservoir 16, and the like. For example, as shown in FIG. 1, when the upper cover 20 has a flat plate shape, the thickness of the second spacers 22a and 22b is necessarily "the thickness of the upper flat plate support 12b + the first spacer. 14a and 14b ".
On the other hand, when the side surface shape of the upper cover 20 is stepped, a larger amount of the fine particle dispersion can be held in the liquid reservoir 16. In this case, the shape of the second spacers 22a and 22b is made to be stepped to match the shape of the side surface of the upper cover 20 so that both side ends of the stepped upper cover 20 and the flat support 12a are sealed.
The length and width of the plate-like supports 12a and 12b (that is, the length and width of the void 18a) are not particularly limited, and depend on the length and width of the fine particle array thin film to be produced. Choose the best one.

The plate-like supports 12a and 12b may be any plate and any material and size can be used. Specific examples of the material of the flat supports 12a and 12b include (1) glass, (2) Si wafer, (3) various metal plates such as iron, stainless steel, and aluminum.
However, when the prepared fine particle array thin film is used as it is in the state of being supported by the flat supports 12a and 12b, at least one of the flat supports 12a and 12b has light with a target wavelength. It is preferable to use a transparent material such as glass or transparent plastic.

Further, in order to produce a fine particle array thin film with few defects, it is necessary to perform treatment for improving wettability to the fine particle dispersion on at least one of the plate-like supports 12a and 12b.
For example, when the dispersion medium of the fine particle dispersion is water and the both surfaces of the fine particle array thin film are used while being sandwiched by the flat plate supports 12a and 12b, the inner surfaces of both the flat plate supports 12a and 12b are used. It is preferable to perform hydrophilic treatment (for example, UV / ozone cleaning). On the other hand, when it is necessary to remove one of the plate-like supports 12a and 12b during the manufacturing process, one of them is subjected to a hydrophilic treatment, and the other (the one to be removed) is subjected to a hydrophobic treatment (for example, tetramethyldisilazane HMDS). , Surface treatment with a silane coupling agent such as octylsilane OTMS and octadecyltrichlorosilane OTS) is preferably performed.

The first spacers 14a and 14b can be made of any material as long as the height of the gap 18a can be kept constant when monodispersed fine particles are arranged and liquid leakage and liquid evaporation can be prevented. Things can be used. The second spacers 22a and 22b may be made of any material as long as they can prevent liquid leakage and liquid evaporation when the monodisperse fine particles are arranged.
Specific examples of the material of the first spacers 14a and 14b include ultra-thin double-sided adhesive tape, polyester, polyolefin (polyethylene, polypropylene, etc.), fluororesin (tetrafluoroethylene, etc.), silicone resin, and the like. Moreover, it is a thin film that can be controlled by a film thickness of about several tens of nanometers formed by a vacuum deposition film, a sputtering film, etc., and it can be used even if it is a thin film made of various materials (for example, metal, ceramics, etc.). Can do.
Specific examples of the material of the second spacers 22a and 22b include silicone sheets, polyesters, polyolefins (polyethylene, polypropylene, etc.), fluororesins (tetrafluoroethylene, etc.), and silicone resins.
Since the upper cover 20 is for holding the fine particle dispersion injected into the liquid reservoir 16, there is no limitation on the material thereof, and treatment for improving the wettability with respect to the fine particle dispersion is not necessarily required. There is no need to apply.

  Next, a method for manufacturing a fine particle array thin film using the fine particle array thin film manufacturing apparatus shown in FIG. 1 will be described. The manufacturing method according to the first embodiment of the present invention is a method of manufacturing a fine particle array thin film in which gas is filled between monodisperse fine particles, and includes an injection step, an alignment step, and an evaporation step. ing.

  The injection step is a step of injecting the fine particle dispersion into the liquid reservoir 16 of the fine particle array thin film manufacturing apparatus 10 described above. When the fine particle dispersion is injected into the liquid reservoir 16, the entire gap 18a is filled with the fine particle dispersion by capillary action. In this case, in order to suppress the evaporation of the dispersion medium from the inlet of the liquid reservoir 16, it is preferable to seal the inlet with a polymer film. Even when the dispersion medium evaporates from the injection port, if there is a sufficient amount of the fine particle dispersion in the liquid reservoir 16 to form the fine particle array in the entire gap 18a, the injection port is sealed. May be omitted.

  Here, the “fine particle dispersion” refers to a solution in which the above-mentioned monodisperse fine particles are dispersed in an appropriate dispersion medium. The dispersion medium is not particularly limited, but it is preferable to use water, an aqueous solution prepared by adding acid, alkali, or the like to water and the like.

  Among the monodispersed fine particles dispersed in the dispersion medium, polymer particles such as polystyrene particles can be synthesized by emulsion polymerization, and ceramic particles such as silica particles can be synthesized by the Stover method.

  Core / shell type particles use polymer particles, ceramic particles, etc. as the core, and a material different from the core particles (for example, polymer fine particles, metal fine particles, ceramic fine particles, or ceramic nanosheets) is electrically charged on the surface. It can be produced by adsorbing by mechanical interaction. Further, when the charge of the core particle and the charge of the shell material are the same, the intermediate layer made of a material having a different charge from the core particle and the shell material and the shell material are alternately adsorbed on the surface of the core particle. By (alternate adsorption method), core / shell type monodispersed fine particles having a desired composition can be produced.

Furthermore, hollow particles can be synthesized by removing the core from such core / shell particles. As the method for removing the core, an optimum method is selected according to the material of the core and the shell. For example, when the core is polymer particles such as polystyrene particles and the shell is made of ceramics such as titania nanosheets, a method of extracting and removing with a solvent that dissolves the polymer particles, a method of firing the polymer particles, a method of treating with oxygen plasma, etc. There is.
For example, when the core is made of silica or the like, there are a method of heating in an aqueous sodium hydroxide solution and a method of etching with an aqueous hydrofluoric acid solution.

As the concentration of the monodispersed fine particles in the fine particle dispersion, an optimum concentration is selected according to the material of the monodispersed fine particles, the average particle diameter, and the like. However, if the concentration of the monodisperse fine particles is too low, the amount of liquid for obtaining a fine particle array thin film having a certain area is increased, and the volume of the liquid reservoir portion 16 needs to be increased. On the other hand, if the concentration of the monodisperse fine particles is too high, the viscosity of the dispersion becomes high, and the fine particle dispersion does not easily penetrate into the thin gap portion 18a.
Specifically, the concentration of the monodisperse fine particles is preferably 0.1 wt% or more and 50 wt% or less, more preferably 1 wt% or more and 20 wt% or less.

The arranging step is a step of arranging the monodisperse fine particles in the void portion 18a. When the fine particle dispersion is injected into the gap 18a, the solvent gradually volatilizes from the first opening 18b, so that the dispersion from the liquid reservoir 16 toward the first opening 18b is dispersed in the gap 18a. Liquid flow occurs. This flow becomes a driving force, and the monodisperse fine particles gradually align from the first opening 18b side. Further, since the fine particle dispersion is supplied from the liquid reservoir 16, the fine particle array thin film grows from the first opening 18a side toward the liquid reservoir 16 side.
When a predetermined time elapses, the entire void portion 18a becomes a fine particle array thin film. At this point, the monodispersed fine particles are in contact with each other, and the dispersion medium is filled between the monodispersed fine particles.

The temperature at which the monodispersed fine particles are arranged is preferably relatively low. When the apparatus is held at a relatively low temperature, the volatilization of the dispersion medium proceeds slowly, so that a fine particle array thin film having a uniform crystal orientation can be obtained. However, if the temperature is too low, the fine particle dispersion may freeze, which is not preferable. Specifically, the temperature at which the monodispersed fine particles are arranged is preferably 0 ° C. or higher and 80 ° C. or lower, more preferably 5 ° C. or higher and 50 ° C. or lower.
The time required for the monodisperse fine particles to be regularly arranged in the entire void portion 18a varies depending on the composition of the fine particle dispersion, the area of the fine particle array thin film, the holding temperature, etc., but is usually several hours to several tens of hours. is there.

The evaporation step is a step of evaporating the dispersion medium contained in the fine particle dispersion liquid from the first opening 18a after the monodisperse fine particles are regularly arranged in the void portion 18a.
The method for removing the dispersion medium is not particularly limited, and various methods can be used. For example, the apparatus 10 may be left at room temperature as it is, and the dispersion medium may be gradually volatilized from the first opening 18a. Alternatively, the dispersion medium may be forcibly evaporated using a heat drying method, a vacuum drying method, a freeze drying method, or the like.

  When the dispersion medium is completely removed, a fine particle array thin film in which adjacent monodispersed fine particles come into contact with each other and gas is filled between the monodispersed fine particles is obtained. Since the obtained fine particle array thin film is not a self-supporting film, it is used in a state in which it is sandwiched between flat plate supports 12a and 12b or in a state in which any one of flat plate supports 12a and 12b is removed. . Alternatively, one or both of the flat supports 12a and 12b may be replaced with a flat support made of another material having a predetermined optical characteristic.

Incidentally, it omitted evaporation process, or, without completely removing the Oite dispersion medium evaporating step may be stopped dried in a state in which a part thereof remained. If the evaporation step is omitted or if the drying is stopped halfway, all or part of the gaps between the monodisperse fine particles are filled with the dispersion medium. Therefore, the fine particle arrangement can be achieved by controlling the remaining amount of the dispersion medium. The optical characteristics of the body thin film can be changed. In this case, if the dispersion medium volatilizes during use, the optical properties of the fine particle array thin film change with time, so that both surfaces of the fine particle array thin film are sandwiched between the plate-like supports 12a and 12b, and the dispersion medium evaporates. It is preferable to seal around it so that it does not occur.

Next, a manufacturing method of the fine particle array thin film according to the second embodiment of the present invention will be described. The manufacturing method according to the present embodiment is a manufacturing method of a fine particle array thin film in which liquid is filled between monodisperse fine particles, and includes an injection step, an alignment step, an evaporation step, and a liquid filling step. Yes. Among these, injection step, aligning step及beauty evaporation step is omitted because it is similar to the first embodiment.

Liquid filling step, after removal of the solvent is between Oite monodisperse particles in the evaporation step, a step of filling a liquid between the monodisperse particles.
The liquid filled between the monodispersed fine particles is not particularly limited, and an optimal one is selected according to the use of the fine particle array thin film, the required characteristics, and the like. Examples of the liquid to be filled include water, an organic solvent, and an ionic liquid described above.

The liquid filling method is not particularly limited,
(1) A method of infiltrating a liquid by capillary action from the first opening 18b or the second opening 18c (hereinafter referred to as “capillary method”),
(2) A method in which the flat plate-like support 12b on the upper surface is removed and a liquid is dropped from the upper surface of the fine particle array thin film (hereinafter referred to as “dropping method”)
Etc. can be used.
In the fine particle array thin film after drying, since the monodispersed fine particles are in contact with each other, even if the dropping method is used, the liquid can be dispersed without disturbing the regular arrangement of the monodispersed fine particles by gently dropping the liquid. Can be filled. Further, the dropping method can efficiently fill the liquid as compared with the capillary method.

  When the amount of liquid to be filled is adjusted, a fine particle array thin film in which adjacent monodispersed fine particles come into contact with each other and all or part of the gaps between the monodispersed fine particles are filled with a predetermined liquid is obtained. Since the obtained fine particle array thin film is not a self-supporting film, it is sandwiched between the plate-like supports 12a and 12b, and in order to prevent the liquid from evaporating, it should be used in a sealed state. preferable. However, when filling with a non-volatile liquid, you may use it in the state which removed any one of flat support body 12a, 12b. Furthermore, before filling with the liquid, one or both of the flat supports 12a and 12b may be replaced with a flat support made of another material having a predetermined optical property.

Next, a manufacturing method of the fine particle array thin film according to the third embodiment of the present invention will be described. The manufacturing method according to the present embodiment is a manufacturing method of a fine particle array thin film in which solids are filled between monodisperse fine particles, and includes an injection step, an alignment step, an evaporation step, and a solid filling step. Yes. Among these, injection step, aligning step及beauty evaporation step is omitted because it is similar to the first embodiment.

Solid filling step, after removing the dispersion medium is between Oite monodisperse particles in the evaporation step, a step of filling the different solids and monodisperse particles between the monodisperse particles.
The solid to be filled between the monodispersed fine particles is not particularly limited, and an optimal one is selected according to the use of the fine particle array thin film, required characteristics, and the like. Examples of the solid to be filled include the polymers, ceramics, and semiconductors described above.

The solid filling method is selected according to the solid material.
For example, when the solid is a polymer, a method in which the polymer is dissolved in an appropriate solvent, and this solution is introduced between the monodispersed fine particles using a capillary method, a dropping method, or the like, and solidified is preferable.
For example, when the solid is a ceramic, a semiconductor, etc.
(1) A method in which an alkoxide solution is introduced between monodispersed fine particles, followed by hydrolysis and condensation,
(2) A method of depositing a solid between monodisperse fine particles using a vapor phase method such as CVD, PVD, sputtering, etc.
and so on.

  When the solid filling conditions are optimized, a fine particle array thin film in which adjacent monodispersed fine particles are in contact with each other and all or part of the voids between the monodispersed fine particles is filled with a predetermined solid is obtained. Since the obtained fine particle array thin film is a self-supporting film, it can be used with one or both of the flat supports 12a and 12b removed. Further, in a state of being sandwiched between the flat plate supports 12a and 12a, or one or both of the flat plate supports 12a and 12b are replaced with a flat plate support made of another material having predetermined optical characteristics. It can also be used in the state. Furthermore, after filling a predetermined solid in a part of the space between the monodisperse fine particles, all or a part of the remaining space may be further filled with the above-described various liquids.

Next, a method for manufacturing a fine particle array thin film according to the fourth embodiment of the present invention will be described. The manufacturing method according to the present embodiment is a manufacturing method of a fine particle array thin film having a so-called “reverse opal structure”, and includes an injection step, an alignment step, an evaporation step, a solid filling step, and a removal step. I have. Among these, injection step, aligning step, evaporation step及 beauty solid filling process will be omitted because it is similar to the third embodiment.

The removing step is a step of removing the monodispersed fine particles after filling the solids between the monodispersed fine particles. As the method for removing the monodisperse fine particles, an optimum one is selected according to the monodisperse fine particles and the solid material filled therearound.
For example, when the monodisperse fine particles are polymer particles and the solid is ceramics, semiconductor, etc., as a removal method,
(1) A method of immersing the fine particle array thin film in a solvent for dissolving the polymer particles and extracting and removing the polymer particles,
(2) A method of burning and removing polymer particles by performing firing treatment, oxygen plasma treatment, etc. on the fine particle array thin film,
Etc. are preferably used.
Further, for example, when the monodispersed fine particles are silica particles and the solid is a polymer, as a removal method, (1) a method of heating in sodium hydroxide, (2) a method of etching with an aqueous hydrofluoric acid solution , Etc. are preferably used.

  When the monodispersed fine particles are removed, solids are filled in the spaces between the monodispersed fine particles, and voids equal to the outer diameter of the monodispersed fine particles are formed in the portions that were the monodispersed fine particles. A fine particle array thin film having an “opposite opal structure” is obtained. Since the obtained fine particle array thin film is a self-supporting film, it can be used with one or both of the flat supports 12a and 12b removed. Further, in a state of being sandwiched between the flat plate supports 12a and 12a, or one or both of the flat plate supports 12a and 12b are replaced with a flat plate support made of another material having predetermined optical characteristics. It can also be used in the state.

  Next, the operation of the fine particle array thin film, the manufacturing method thereof, and the fine particle array thin film manufacturing apparatus according to the present invention will be described. FIG. 2 is a schematic diagram showing a state change of the fine particle dispersion introduced into the void 18a of the fine particle array thin film manufacturing apparatus 10. As shown in FIG. When the fine particle dispersion is injected into the liquid reservoir 16 of the fine particle array thin film manufacturing apparatus 10, the fine particle dispersion enters the gap 18a by capillary action. At this time, the monodispersed fine particles 30 in the voids 18a are in a randomly dispersed state as shown in FIG.

If left at a predetermined temperature in this state, the dispersion medium in the fine particle dispersion gradually volatilizes from the first opening 18b, so that the liquid reservoir 16 passes through the first opening 18b in the gap 18a. A unidirectional flow is generated. This becomes a driving force, and the monodisperse fine particles 30 gather near the first opening 18b.
At this time, since an electrostatic repulsive force acts between the monodispersed fine particles 30, the monodispersed fine particles 30 are regularly arranged in the vicinity of the first opening 18b as shown in FIG. Further, when the conditions for arranging the monodisperse fine particles 30 are optimized, the monodisperse fine particles 30 are deposited on the close-packed structure by the flow force. Specifically, the monodisperse fine particles 30 are deposited so that the film surface is a (111) plane and the drying direction is a <1-10> direction under predetermined conditions.

Further, when the temperature is maintained at a predetermined temperature in this state, the fine particle dispersion is sequentially replenished from the liquid reservoir 16, so that a region where the monodisperse fine particles 30 are regularly arranged grows toward the liquid reservoir 16. Then, after a predetermined time has elapsed, as shown in FIG. 2 (c), the fine particle array thin film is formed in the entire gap 18a.
Thereafter, (1) the first opening 18 b and the second opening 18 c are sealed while the dispersion medium is filled between the monodispersed fine particles 30, and (2) the remaining between the monodispersed fine particles 30. (3) After the dispersion medium is completely removed, a liquid or a solid is filled between the monodispersed fine particles 30, or (4) a solid is added between the monodispersed fine particles 30. After the filling, if the monodispersed fine particles 30 are removed, the fine particle arrayed thin film according to the present invention can be obtained.

  In the manufacturing apparatus and the manufacturing method using the same according to the present invention, a unidirectional flow is generated in the void portion 18a and the monodisperse fine particles 30 are regularly arranged using this as a driving force. A single crystal thin film with uniform orientation can be easily obtained. Moreover, since the drying location is limited to one location, the drying proceeds very slowly. Therefore, the generation density of cracks during drying is extremely small, and the width of cracks is significantly narrower than that of the conventional method. In addition, since the monodisperse fine particles are in contact with each other, they are resistant to impact. Further, in the fine particle array thin film in which gas and / or solid is filled in the gaps between the monodispersed fine particles 30, there is no change with time in optical characteristics due to evaporation of the liquid.

  Furthermore, since the liquid reservoir 16 is provided on the rear end side of the void 18a, the fine particle dispersion can be efficiently supplied from the liquid reservoir 16 to the void 18a. Therefore, a large-area thin film close to a single crystal state can be obtained from an extremely small amount of dispersion. In addition, although the obtained thin film includes point defects and stacking faults, it has a crystal state close to a single crystal, and there are almost no crystal grain boundaries present in a polycrystalline state. Also, the density of cracks is extremely low. Therefore, when the fine particle array thin film according to the present invention is applied to various optical elements for Bragg reflection of visible light, excellent characteristics such as high wavelength selectivity and high reflectance are exhibited.

Example 1
[1. Production of fine particle array thin film manufacturing apparatus]
A fine particle array thin film manufacturing apparatus 10 shown in FIG. 1 was produced. For the flat supports 12a and 12b and the upper cover 20, slide glass (Matsunami S-111, 76 × 26 × 1 mm) subjected to UV / ozone cleaning was used. Further, an ultrathin double-sided adhesive tape (Nitto Denko, No. 5601) having a thickness of 10 μm was used for the first spacers 14a and 14b. Furthermore, a silicone sheet having a thickness of 1 mm was used for the second spacers 22a and 22b. In the case of this example, the area of the gap 18a was 45 mm × 20 mm.

[2. Preparation of fine particle array thin film]
The concentration of the monodispersed silica fine particle aqueous dispersion (KE-W30, manufactured by Nippon Shokubai Co., Ltd., average particle size: 290 nm) was adjusted to 5 wt% with ion-exchanged water, and this was the liquid reservoir of the fine particle array production apparatus 16 was injected. The amount of liquid injected was approximately 0.3 ml. The fine particle dispersion injected into the liquid reservoir 16 immediately entered the gap 18a by capillary action, and reached the first opening 18a in about 10 seconds after the injection.
After injecting the fine particle dispersion, the inlet of the liquid reservoir 16 is sealed with PARAFILM (registered trademark, manufactured by Perchiney Plastic Packaging, Inc. (175 Western Avenue, Neenah, WI 54956 USA)) and room temperature (23 ° C. to 25 ° C.). (C).

[3. Evaluation]
FIG. 3 shows the result of observing the process from the injection of the fine particle dispersion into the liquid reservoir 16 until the fine particle array thin film is obtained. From this observation, it was found that the final fine particle array thin film (state C) was formed through three stages of changes (states A, B, and C).
That is, immediately after injecting the fine particle dispersion, as shown in FIG. 3A, the dispersion in the gap 18a was transparent. When about 10 hours passed after injecting the fine particle dispersion, as shown in FIG. 3B, the entire void portion 18a changed to a state A showing an iris color (pink) peculiar to a colloidal crystal. Moreover, when about 50 hours passed after injecting the fine particle dispersion, as shown in FIG. 3 (c), the entire void portion 18a changed to a state B exhibiting a light pink color. Furthermore, when about 180 hours passed after injecting the fine particle dispersion, as shown in FIG. 3 (d), the entire gap portion 18a changed to a state C in which the color was light green.

For each stage of states A, B, and C, reflection spectrum analysis was performed using the angle-resolved reflection spectrum method. FIG. 4 shows an example of reflection spectrum analysis.
What is reflection spectrum analysis?
(1) The reflection spectrum is measured at a plurality of incident angles (FIG. 4 (a)),
(2) The reflection peak wavelength is plotted against the measured incident angle (FIG. 4 (b)),
(3) The obtained plot was fitted with the Bragg equation (λ _peak = 2d (n _eff ² −sin ² θ) ^1/2, d: distance between lattice planes, n _eff : effective refractive index), and the lattice plane Find the distance d and the effective refractive index n _eff
Say that.

Table 1 shows the inter-lattice distance d and the effective refractive index n _eff obtained by angle-resolved reflection spectrum measurement. From Table 1, it was found that the state A is a state in which the silica fine particles are regularly arranged in close packing so that the silica fine particles are in contact with each other, and water as a dispersion medium is filled in the gaps between the regularly arranged fine particles. Further, it was found that the state C is a state in which the silica fine particles are regularly arranged in a close-packed manner, and the gaps between the regularly arranged fine particles are filled with air. Furthermore, it was found that the state B is an intermediate state between the state A and the state C, and a slight amount of water as a dispersion medium remains in the gaps between regularly arranged fine particles.

  Next, the result of evaluating the particle arrangement state (crystallinity) of the obtained fine particle array thin film (state C) is shown. FIG. 5 shows the result of observing the surface of the fine particle array thin film using a scanning electron microscope (SEM) by removing one of the two slide glasses for observation. FIG. 6 shows an SEM photograph of the fine particle array thin film produced by the pulling method disclosed in Non-Patent Document 1 as a comparison. FIG. 5A and FIG. 6 are substantially the same magnification.

As shown in FIG. 6, the fine particle array thin film disclosed in Non-Patent Document 1 shows that cracks are generated at intervals of 20 to 30 μm. In the case of FIG. 6, the crack area ratio was 8.4% in a 200 × 300 μm region. The crack width was 5 to 20 times (1 to 4 μm) the particle diameter.
In contrast, as shown in FIG. 5A, the fine particle array thin film obtained in this example had a very low crack generation density and a crack spacing of about 100 μm. In the case of FIG. 5A, the area ratio of cracks was 1.3% in a 200 × 300 μm region. Further, as shown in FIG. 5 (b), although the presence of stacking faults, point defects, and particles adhering to the surface is recognized, the presence of crystal grain boundaries is not recognized, and at least about 20 × 30 μm observed. It can be seen that the region is in a single crystal state. In addition, it is thought that the particles adhering to the surface adhered when the slide glass was peeled off. Furthermore, as shown in FIG.5 (c), the width of the crack was about 0.5 to 2.0 times the particle diameter.

  Next, the crystallinity of a wider area was evaluated. FIG. 7 shows an appearance photograph of the obtained fine particle array thin film. SEM observation was performed in the vicinity of the marks A to E in FIG. 7, and a two-dimensional Fourier transform was performed on a 10 × 10 μm region of the obtained image. FIG. 8 shows the obtained pattern. Each pattern shows a 6-fold symmetrical spot pattern, and the direction in which the spot appears from the center of the pattern is almost the same. This indicates that at each point of A to E shown in FIG. 7, the fine particles are arranged in a hexagonal crystal structure (closest packed structure), and the crystal orientation is almost uniform. . That is, the fine particle array thin film obtained in this example has a uniform crystal orientation in the film plane, indicating that it is close to a single crystal state.

(Comparative Example 1)
An aqueous dispersion of monodispersed silica fine particles (KE-W30, manufactured by Nippon Shokubai Co., Ltd., average particle size: 290 nm)) was adjusted to a concentration of 5 wt% with ion-exchanged water, and this was subjected to UV / ozone cleaning slide glass ( One drop was dropped on a matsunami S-1111 (76 × 26 × 1 mm) using a dropper and dried at room temperature to prepare a fine particle array thin film.
FIG. 9 shows an SEM photograph of the prepared fine particle array thin film. FIG. 9 shows that the presence of crystal grain boundaries is observed even in a region of only about 20 × 30 μm, and the obtained thin film is in a polycrystalline state.

The reflection spectrum of the fine particle array thin film obtained in Example 1 and Comparative Example 1 was measured. For the measurement, a multi-channel type spectrometer S-2650 manufactured by Soma Optical Co., Ltd. was used, a halogen lamp was used for incident light, and the incident angle measured from the normal of the thin film surface was 9 ° and the detection angle was 9 °. Then, a wavelength range of 300 to 1000 nm was measured. FIG. 10 shows the result. In addition, the vertical axis | shaft of FIG. 10 was represented by the reflectance when the reflectance from an Al mirror is 100%.
As shown in FIG. 10, the fine particle array thin film prepared in Example 1 has higher reflectance and a smaller half-value width of the reflection peak, and has excellent characteristics as an optical filter that reflects a specific wavelength. Recognize. This is due to the excellent crystallinity of the fine particle array thin film obtained in Example 1.

(Example 2)
In accordance with the same procedure as in Example 1, the fine particle dispersion was poured into the reservoir 16 and dried at room temperature. Approximately 10 hours have passed since the start of drying, and when the entire gap 18a became in the state A shown in FIG. 3B, the fine particle dispersion remaining in the liquid reservoir 16 was removed. Furthermore, the first opening 18b and the second opening 18c were sealed using an ultraviolet curable resin, and a fine particle array thin film in which the fine particles were arranged in the closest packing and the gaps were filled with water was obtained. .

FIG. 11 shows an appearance photograph of the obtained fine particle array thin film. Example 1 in which the refractive index of silica particles constituting the fine particle array thin film is 1.45, the refractive index of water of the medium is 1.33, and the periphery of the fine particles is filled with air (refractive index: 1.0) Compared with the fine particle array thin film, the difference in refractive index between the fine particles and the medium is small, so that it is found that a thin film having high visible light permeability is obtained with little influence of light scattering by the fine particles.
FIG. 12 shows a reflection spectrum measured for the fine particle array thin film obtained in this example. The measurement conditions were the same as in Example 1. In this example, since silica fine particles having an average particle diameter of 290 nm are used, the reflection peak wavelength is in the infrared region. This indicates that the fine particle array thin film obtained in this example may be applicable to an infrared reflecting film that is transparent to visible light and reflects infrared light. In addition, by using fine particles having a smaller particle diameter, it is possible to produce an optical filter film that reflects light of a specific wavelength in the visible light region and has high transmittance of light of other wavelengths. It is shown that.

(Example 3)
In accordance with the same procedure as in Example 1, after preparing a fine particle array thin film filled with air between the fine particles, the fine particle array having the same structure as in Example 2 was filled with water from the first opening 18b. A thin film was prepared. When the reflection spectrum of the obtained fine particle array thin film was measured under the same conditions as in Example 2, a reflection spectrum equivalent to that in Example 2 was shown, although not shown.

Example 4
In accordance with the same procedure as in Example 1, the fine particle dispersion was poured into the reservoir 16 and dried at room temperature. Approximately 10 hours have passed since the start of drying, and when the entire gap 18a is in the state A shown in FIG. 3 (b), the entire solution is frozen with liquid nitrogen, and then placed in a vacuum dryer to perform freeze-drying. went. When it was taken out 24 hours after the start of freeze-drying, it was changed to the same state as state C shown in FIG. 3D, and formation of a fine particle array thin film composed of fine particles and air was observed. By using lyophilization, a fine particle array thin film composed of fine particles and air could be produced from the fine particle dispersion in less than 40 hours.

  Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the present invention.

  The fine particle array thin film according to the present invention can be used as a template for obtaining an optical element such as a narrow band filter and a reverse opal structure fine particle array thin film expected as a photonic crystal.

1 (a) is a perspective view of a fine particle array thin film manufacturing apparatus according to the present invention, FIG. 1 (b) is a front view thereof, FIG. 1 (c) is a plan view thereof, and FIG. 1 (d) is a right side view thereof. It is. It is a schematic diagram which shows the process in which the monodisperse fine particles in the fine particle dispersion liquid introduce | transduced into the space | gap part of the fine particle array thin film manufacturing apparatus shown in FIG. 1 are arranged. It is a photograph which shows the external appearance change accompanying drying of the fine particle dispersion liquid introduce | transduced into the space | gap part of the fine particle array thin film manufacturing apparatus shown in FIG. FIG. 4A is a diagram illustrating an example of a reflection spectrum using the angle-resolved reflection spectrum method, and FIG. 4B is a plot of the peak wavelength obtained in FIG. 4A with respect to the incident angle. FIG. FIG. 5A and FIG. 5B are a low-magnification SEM photograph (× 350) and a high-magnification SEM photograph (× 4000), respectively, of the fine particle array thin film obtained in Example 1, and FIG. c) is an enlarged SEM photograph (× 8000) near the crack. 4 is a low-magnification SEM photograph (× 350) of a fine particle array thin film disclosed in Non-Patent Document 1. 2 is an appearance photograph of a fine particle array thin film obtained in Example 1. FIG. 7 is a spot pattern obtained by performing a two-dimensional Fourier transform on the positions of fine particles in a 10 × 10 μm region at points A to E shown in FIG. 7. 4 is a high-magnification SEM photograph (× 4000) of the fine particle array thin film obtained in Comparative Example 1. It is a figure which shows the reflection spectrum of the fine particle array thin film obtained in Example 1 and Comparative Example 1. 2 is an external appearance photograph of a fine particle array thin film obtained in Example 2. FIG. 6 is a diagram showing a reflection spectrum of a fine particle array thin film obtained in Example 2. FIG.

Claims (20)

It has a thin film in which monodisperse fine particles are regularly arranged.
Have a uniform periodic structure crystal orientation in the film plane,
The area ratio of cracks is Ri der than 8%, and,
The fine particle array thin film, wherein the thin film has a size of 45 mm x 20 mm or more .   2. The fine particle array thin film according to claim 1, wherein a width of the crack is 4 times or less of a diameter of the monodispersed fine particles.   The fine particle array thin film according to claim 1 or 2, wherein the thin film has a thickness of 0.2 mm or less.   The fine particle array thin film according to any one of claims 1 to 3, wherein one surface or both surfaces of the thin film are supported by a flat support.   The fine particle array thin film according to claim 4, wherein a gas is filled between the monodispersed fine particles.   The fine particle array thin film according to claim 4 or 5, wherein a liquid is filled between the monodispersed fine particles.   The fine particle array thin film according to any one of claims 1 to 6, wherein the monodispersed fine particles are filled with a solid different from the monodispersed fine particles.   A fine particle array thin film having an inverse opal structure obtained by removing the monodisperse fine particles from the fine particle array thin film according to claim 7.   The fine particle array thin film according to any one of claims 1 to 8, wherein the monodisperse fine particles have an average particle diameter of 50 nm to 2 µm.   The fine particle array thin film according to any one of claims 1 to 9, wherein the monodispersed fine particles have a (111) -oriented face-centered cubic structure in a film thickness direction or a hexagonal close-packed structure. One becomes the lower surface, as the other is the upper surface side, two flat plate-like support which face each other with a spacing of Jo Tokoro,
At least both ends of the two flat plate supports are sealed, a gap is formed between the two flat plate supports, and a first opening is formed at the tip of the two flat plate supports. A pair of spacers for forming
A reservoir portion for holding a fine particle dispersion in which monodisperse fine particles are dispersed, provided on the rear end side of the two plate-like supports;
A fine particle array thin film manufacturing apparatus comprising:   12. The fine particle array according to claim 11, wherein the liquid reservoir portion supplies the fine particle dispersion liquid to the gap portion from a second opening formed at a rear end of the two flat plate-like supports. Thin film manufacturing equipment.   The apparatus for producing a fine particle array thin film according to claim 11 or 12, wherein an interval between the two plate-like supports is larger than an average particle diameter of the monodispersed fine particles and 0.2 mm or less. A method for producing a fine particle array thin film using the fine particle thin film production apparatus according to any one of claims 11 to 13,
An injection step of injecting the fine particle dispersion into the liquid reservoir;
An arranging step of arranging the monodispersed fine particles in the voids;
A method for producing a fine particle array thin film comprising:   The method for producing a fine particle array thin film according to claim 14, further comprising an evaporation step of evaporating a dispersion medium contained in the fine particle dispersion from the first opening.   16. The method for producing a fine particle array thin film according to claim 15, wherein the evaporation step evaporates the dispersion medium using a heat drying method, a vacuum drying method or a freeze drying method.   The method for producing a fine particle array thin film according to claim 15 or 16, further comprising a liquid filling step of filling a liquid between the monodispersed fine particles after the evaporation step.   The method for producing a fine particle array thin film according to claim 17, wherein the liquid is water, an organic solvent, or an ionic liquid.   The method for producing a fine particle array thin film according to claim 15 or 16, further comprising a solid filling step of filling a solid different from the monodispersed fine particles between the monodispersed fine particles after the evaporation step.   20. The method for producing a fine particle array thin film according to claim 19, further comprising a removal step of removing the monodispersed fine particles after the solid filling step.

Images