Photon up-conversion film and method for manufacturing the same

Abstract

The present invention can provide a photon up-conversion film and a simple manufacturing method thereof, wherein the photon up-conversion film is a film that can perform high-efficiency up-conversion even in air or under low-intensity light. The photon up-conversion film of an embodiment of the present invention has a matrix and a void portion formed of a resin, and at least includes: a sensitizing component that can absorb light in a first wavelength region λ1; and a luminescent component that can emit light in a second wavelength region λ2 with a wavelength shorter than the first wavelength region λ1; the sensitizing component and the luminescent component are present at the interface between the matrix and the void portion.

Description

Technical Field

[0001] The invention relates to a photon up-conversion film and a manufacturing method thereof. Background Art

[0002] Photon up-conversion (hereinafter sometimes referred to as "up-conversion") technology, which converts low-energy light into high-energy light, is expected to be applied to various fields such as solar cells or solar power generation, photocatalysts, bioimaging, optical equipment, etc. As up-conversion luminescence in organic materials, a technology that utilizes triplet-triplet annihilation (TTA) that occurs when triplet molecules collide with each other is known. In the up-conversion using TTA, in a solution system in which a donor compound and an acceptor compound are dissolved in a solvent, energy is efficiently transferred by diffusion of the donor compound molecules and the acceptor compound molecules. On the other hand, the solution system has the problem of limited practical application areas.

[0003] Due to the above situation, research and development of upconversion luminescence in a solid state has been continued. However, since molecular diffusion hardly occurs in a solid state, there is a problem that TTA cannot be used efficiently. For example, a resin film with a donor compound and an acceptor compound introduced has been studied, but the upconversion luminescence intensity is not sufficient.

[0004] Furthermore, conventional upconversion technologies do not adequately convert low-intensity light (such as sunlight), and particularly do not adequately convert near-infrared light to visible light. Furthermore, conventional upconversion technologies do not adequately perform upconversion in air.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent No. 5491408 Summary of the invention

[0008] Problem that the invention aims to solve

[0009] The present invention is made to solve the above-mentioned conventional problems, and its main purpose is to provide a photon up-conversion film and a simple manufacturing method thereof, wherein the photon up-conversion film is a film that can perform high-efficiency up-conversion even in air or under low-intensity light.

[0010] Means for solving problems

[0011] The photon up-conversion film of an embodiment of the present invention has a matrix and a void portion formed by a resin, and at least includes: a sensitizing component that can absorb light located in a first wavelength region λ1; and a luminescent component that can emit light located in a second wavelength region λ2 with a wavelength shorter than that of the first wavelength region λ1; the sensitizing component and the luminescent component are present at the interface between the matrix and the void portion.

[0012] In one embodiment, the porosity of the photon up-conversion film is 5.0 volume % to 60.0 volume %.

[0013] In one embodiment, the void portion has independent cells and an open cell structure in which a plurality of cells are connected.

[0014] In one embodiment, the resin is a water-soluble resin selected from polystyrene sulfonate, polyethylene oxide, polyethyleneimine, polyvinyl alcohol resin and cellulose resin. In another embodiment, the resin is an oil-soluble resin selected from (meth)acrylic resin and polystyrene.

[0015] In one embodiment, the photon up-conversion film comprises 7.00×10 -9 mol~5.00×10 -6 mol of the sensitizing component, and 5.00×10 -6 mol~7.00×10 - 5 mol of the above luminescent component.

[0016] In one embodiment, the first wavelength range λ1 is 510 nm to 550 nm, the second wavelength range λ2 is 400 nm to 500 nm, the sensitizing component is the following compound, and the luminescent component is the following compound:

[0017] <sensitizing ingredient>

[0018] [Chemical formula 1]

[0019]

[0020] <Luminous Components>

[0021] [Chemical formula 2-1]

[0022]

[0023] [Chemical formula 2-2]

[0024]

[0025] In one embodiment, the first wavelength region λ1 is 610 nm to 650 nm, the second wavelength region λ2 is 500 nm to 600 nm, the sensitizing component is the following compound, and the luminescent component is the following compound:

[0026] <sensitizing ingredient>

[0027] [Chemical formula 3]

[0028]

[0029] <Luminous Components>

[0030] [Chemical formula 4]

[0031]

[0032] In one embodiment, the first wavelength region λ1 is 700 nm to 810 nm, the second wavelength region λ2 is 500 nm to 700 nm, the sensitizing component is the following compound, and the luminescent component is the following compound:

[0033] <Sensitizing ingredient>

[0034] [Chemical formula 5]

[0035]

[0036] <Luminous Components>

[0037] [Chemical formula 6]

[0038]

[0039] [Chemical formula 7]

[0040]

[0041] In one embodiment, the first wavelength region λ1 is 700 nm to 730 nm, the second wavelength region λ2 is 400 nm to 500 nm, the sensitizing component is the following compound, and the luminescent component is the following compound:

[0042] <sensitizing ingredient>

[0043] [Chemical formula 8]

[0044]

[0045] <Luminous Components>

[0046] [Chemical formula 9]

[0047]

[0048] In one embodiment, the first wavelength region λ1 is 410 nm to 500 nm, the second wavelength region λ2 is 300 nm to 400 nm, the sensitizing component is the following compound, and the luminescent component is the following compound:

[0049] <sensitizing ingredient>

[0050] [Chemical formula 10]

[0051]

[0052] <Luminous Components>

[0053] [Chemical formula 11]

[0054]

[0055] In one embodiment, the sensitizing component is a quantum dot, and the luminescent component is the following compound:

[0056] [Chemical formula 12]

[0057]

[0058] [Chemical formula 13]

[0059]

[0060] In one embodiment, the photon up-conversion film can perform up-conversion luminescence at -196°C to 180°C.

[0061] According to another aspect of the present invention, a method for manufacturing a photon upconversion film is provided. One of the manufacturing methods comprises the following steps: preparing an oil-in-water emulsion from an aqueous solution of a water-soluble resin and an oily solvent solution or oily solvent dispersion of a sensitizing component and a luminescent component; applying the oil-in-water emulsion on a substrate to form a coating film; drying the coating film; and applying external force and / or heat to the dried coating film to form a thin film, the thin film having a matrix and a void portion formed by the water-soluble resin, and the sensitizing component and the luminescent component are present at the interface between the matrix and the void portion.

[0062] Another manufacturing method comprises the following steps: preparing a water-in-oil emulsion from an oily solvent solution of an oil-soluble resin and an aqueous solution or a water dispersion of a sensitizing component and a luminescent component; applying the water-in-oil emulsion on a substrate to form a coating film; drying the coating film; and forming a thin film by the drying, wherein the thin film has a matrix and a void portion formed by the oil-soluble resin, and the sensitizing component and the luminescent component are present at the interface between the matrix and the void portion.

[0063] Effects of the Invention

[0064] According to an embodiment of the present invention, a photon up-conversion film is formed by a porous film having a matrix and a void portion, and a sensitizing component and a luminescent component are present at the interface between the matrix and the void portion, thereby realizing a photon up-conversion film that can perform high-efficiency up-conversion even in air or under low-intensity light. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Figure 1 This is a conceptual diagram of energy levels that explains the mechanism of upconversion.

[0066] Figure 2 This is a microscope image showing the comparison of the states of the dry coating film before and after being peeled off from the substrate in the method for producing the up-conversion thin film according to the embodiment of the present invention.

[0067] Figure 3 This is a photographic image showing upconversion when low-intensity light of the level of sunlight is incident on the upconversion film of Example 1.

[0068] Figure 4 is a scanning electron microscope (SEM) photograph image of a cross section of the upconversion thin film of Example 3.

[0069] Figure 5 is a scanning electron microscope (SEM) photograph image of a cross section of the upconversion film of Example 7. DETAILED DESCRIPTION

[0070] Embodiments of the present invention will be described below, but the present invention is not limited to these embodiments.

[0071] A. Photon Upconversion Film

[0072] A-1. Mechanism of photon upconversion

[0073] Reference Figure 1 First, the donor absorbs the incident light and is excited by the singlet state S D The excited triplet state T D Then, triplet-triplet energy transfer (TTET) occurs from the donor to the acceptor, generating an excited triplet state T A Then, in the excited triplet state T A The receptors diffuse and collide with each other, thus producing triplet-triplet annihilation (TTA). As a result, a highly excited singlet energy state S of the receptor is generated. A Then from this highly excited singlet energy state S A Upconverted light (light with greater energy than the excitation light) is emitted.

[0074] A-2. Overall composition of photon upconversion film

[0075] The photon upconversion film (hereinafter sometimes referred to as "upconversion film") of an embodiment of the present invention has a matrix and a void portion formed by a resin. That is, the upconversion film is typically a porous film. The upconversion film includes at least: a sensitizing component (donor) that can absorb light located in the first wavelength region λ1; and a luminescent component (acceptor) that can emit light located in the second wavelength region λ2 of a shorter wavelength than the first wavelength region λ1. In an embodiment of the present invention, the sensitizing component and the luminescent component are present at the interface between the matrix and the void portion of the porous film. Typically, the sensitizing component and the luminescent component are present at the interface between the matrix and the void portion in a mixed state. Typically, the sensitizing component and the luminescent component are located near each other in a manner that allows energy transfer. According to the manufacturing method described in item B below, the sensitizing component and the luminescent component can be present at the interface between the matrix and the void portion of the porous film. The presence of the sensitizing component and the luminescent component at the interface between the matrix and the void portion can be confirmed based on the results of time-of-flight secondary ion mass spectrometry (TOF-SIMS) and scanning electron microscope (SEM) photo images. In addition, the method for confirming the presence position of the sensitizing component and the luminescent component will be described in detail in the following embodiments. By forming an upconversion film from a porous film and making the sensitizing component and the luminescent component present at the interface between the matrix and the void portion, compared with the upconversion formed by the resin film only mixed with the sensitizing component and the luminescent component, up to hundreds of times of upconversion luminescence intensity can be achieved. A considerable part of the advantages can be obtained by forming an upconversion film from a porous film. In more detail, it is speculated that it may be due to the following mechanism: by forming an upconversion film from a porous film, the upconversion light will be repeatedly diffused and scattered inside the film, thereby making the light extraction efficiency of light extracted from the film leap-forward, and the aggregation of sensitizing component molecules and / or luminescent component molecules that may be the main cause of triplet exciton deactivation can be significantly suppressed. In addition, by making the sensitizing component and the luminescent component present at the interface between the matrix and the void portion, the sensitizing component and the luminescent component can be suppressed from being brought into the entanglement of the resin molecules of the matrix, and as a result, the frequency of diffusion and collision can be particularly increased. In addition, the mechanism described in the specification of this application is only a speculation, does not deny the possibility of other mechanisms, and does not limit the present invention.

[0076] In one embodiment, the photon up-conversion film can perform up-conversion luminescence in the temperature range of -196°C to 180°C. If the sensitizing component and the luminescent component exist in a liquid state dissolved in a solvent, it is difficult to perform up-conversion luminescence below the melting point of the solvent. In contrast, it is speculated that the sensitizing component and the luminescent component contained in the photon up-conversion film in this embodiment are different from the liquid state, and exist in a solid state (or a state relatively closer to a solid than a liquid). Therefore, the photon up-conversion film can perform up-conversion luminescence in the entire temperature range of -196°C to 180°C.

[0077] The porosity of the upconversion film is preferably 5.0 volume % to 60 volume %, more preferably 7.0 volume % to 60 volume %, and more preferably 7.0 volume % to 50 volume %. If the porosity is within the range, the sensitizing component and the luminescent component can be appropriately present at the interface between the matrix and the void portion. The porosity can be controlled by adjusting the oil droplet ratio of the water-in-oil emulsion or the water droplet ratio of the oil-in-water emulsion when manufacturing the upconversion film. The details of the method for manufacturing the upconversion film will be described in item B below. In addition, the porosity can be calculated, for example, based on the value of the refractive index measured by the ellipsometer using the Lorentz-Lorenz's formula, or it can be obtained from a scanning electron microscope (SEM) image using any appropriate image analysis processing.

[0078] The surface density of the upconversion film is preferably 0.002 g / cm 2 ~0.006g / cm 2 , preferably 0.0025 g / cm 2 ~0.0055g / cm 2 , more preferably 0.003 g / cm 2 ~0.005g / cm 2 If the surface density is within the above range, the desired porosity can be easily achieved. The surface density can be obtained by, for example, measuring the weight of a test sample punched into a predetermined shape with an electronic balance and dividing the weight by the area of ​​the main surface of the test sample.

[0079] The density of the upconversion film is preferably 0.3 g / cm 3 ~1.7g / cm 3 , preferably 0.35 g / cm 3 ~1.6g / cm 3 , more preferably 0.4 g / cm 3 ~1.5g / cm 3 If the density is within the above range, the desired porosity can be easily achieved. The density can be obtained by, for example, measuring the weight of a test sample punched into a predetermined shape with an electronic balance and dividing the weight by the volume of the test sample.

[0080] The upconversion film may be a porous film having any appropriate micropores. In other words, the void portion of the upconversion film may have any appropriate micropore structure. In one embodiment, the void portion may also have a micropore structure like pumice. Moreover, as described in item B below, it can be inferred that the void portion can be formed by, for example, applying external force and / or heat to the compressed oil droplet portion in the dried coating film of the water-in-oil emulsion, and then releasing the pressure of the compressed oil droplet portion to form a foam-like state. Therefore, in one embodiment, the void portion may also have a foam-like structure (bubble structure).

[0081] The void portion may be formed only of independent bubbles, may have a continuous bubble structure in which a plurality of bubbles are connected, or may be formed by a combination of these.

[0082] The average size of the voids (holes) in the void portion is preferably 0.2 μm to 400 μm, more preferably 0.2 μm to 200 μm, and more preferably 0.2 μm to 100 μm. If the average size of the voids (holes) is within the range, the sensitizing component and the luminescent component can be appropriately present at the interface between the matrix and the void portion. The average size of the voids (holes) can be controlled by adjusting the average size of the oil droplets of the water-in-oil emulsion or the average size of the water droplets of the oil-in-water emulsion when manufacturing the upconversion film. The average size of the voids (holes) can be measured using the BET test method, and can also be quantified from the SEM image by any appropriate image analysis process.

[0083] The thickness of the upconversion film is preferably 5 μm to 200 μm, more preferably 10 μm to 150 μm, and more preferably 15 μm to 100 μm. If the thickness of the upconversion film is within the above range, the desired void portion can be well formed in the entire region in the thickness direction of the film. If the thickness is too large, sometimes a void cannot be formed in the center of the thickness direction of the film, and as a result, the desired upconversion cannot be achieved. If the thickness is too small, sometimes the film shape cannot be maintained.

[0084] The voids of the upconversion film are not filled with liquid (typically a liquid containing a sensitizing component and a luminescent component). Therefore, even if it is formed into a thin film shape (especially a thinner film shape as described above), the liquid will not seep out to the surface of the upconversion film, and the upconversion film is suitable for application to various industrial products. In addition, if the voids of the upconversion film are not filled with liquid, the solvent used to manufacture the upconversion film may also remain in the upconversion film. It can be inferred that there are gases such as solvent vapor or water vapor in the voids, or substances such as granular forms formed by swelling the pigment.

[0085] A-3. Matrix

[0086] As described above, the matrix is ​​formed of a resin. The resin can be appropriately selected according to the method for producing the upconversion film. Specifically, the resin can be a water-soluble resin or an oil-soluble resin.

[0087] As the water-soluble resin, any appropriate water-soluble resin can be used as long as it can form a matrix. Specific examples of the water-soluble resin include polystyrene sulfonate, polyethylene oxide, polyethyleneimine, polyvinyl alcohol resin, and cellulose resin. Examples of polystyrene sulfonate include sodium polystyrene sulfonate. Examples of polyethyleneimine include polyethyleneimine hydrochloride. Examples of polyvinyl alcohol resin include polyvinyl alcohol, amine-modified polyvinyl alcohol, and carboxylic acid-modified polyvinyl alcohol. Examples of cellulose resin include hydroxyethyl cellulose.

[0088] As long as the oil-soluble resin can form a matrix, any appropriate oil-soluble resin can be used. Specific examples of the oil-soluble resin include (meth)acrylic resins, polystyrene, polycarbonate resins, and polyester resins. Examples of (meth)acrylic resins include polymethyl methacrylate (PMMA). Examples of polyester resins include polyethylene terephthalate (PET).

[0089] The Hansen solubility parameter (HSP) distance Ra between the resin forming the matrix and the sensitizing component and the luminescent component is, for example, 10 (MPa) each. 1 / 2 Above, for example, 11 (MPa) 1 / 2 Above, and preferably 12 (MPa) 1 / 2 Above, more preferably 15 (MPa) 1 / 2 More than, more preferably 18 (MPa) 1 / 2 On the other hand, the HSP distance Ra between the resin forming the matrix and the sensitizing component and the luminescent component is, for example, 25 (MPa) 1 / 2 Below, preferably 23 (MPa) 1 / 2 Below, more preferably 21 (MPa) 1 / 2 The HSP distance Ra being within the above range means that the resin forming the matrix has low affinity with each of the sensitizing component and the luminescent component. As a result, the migration of the sensitizing component and the luminescent component into the matrix can be significantly inhibited, and the sensitizing component and the luminescent component can be present at the interface between the matrix and the void portion of the porous film through the synergistic effect with the effect brought about by the manufacturing method described in the subsequent item B.

[0090] HSP is the division of the Hildebrand solubility parameter into three components: dispersion force (δD), permanent dipole intermolecular force (δP), and hydrogen bonding force (δH), and is represented by a vector drawn into a three-dimensional space. It can be judged that the solubility of the vectors is high. That is, the similarity of solubility can be judged from the HSP distance Ra between each other. The definition and calculation of HSP are recorded in Hansen Solubility Parameters: A Users Handbook (CRC Press, 2007) by Charles M. Hansen. Regarding HSP values, various resins and solvents have known values, which can be used directly, or values ​​calculated using the computer software HSPiP (Hansen Solubility Parameters in Practice) can be used. In addition, the HSPiP also has a database of resins and solvents.

[0091] Resin (HSP value: δD R ,δP R , δH R ) and the sensitizing component or luminescent component (HSP value: δD C ,δP C , δH C ) can be calculated by formula (1).

[0092] Ra={4×(δD R -δD C )2+(δP R -δP C )2+(δH R -δH C )2}1 / 2…(1)

[0093] In formula (1), δD R Indicates the dispersion force of the resin, δP R Indicates the permanent dipole intermolecular force of the resin, δH R Indicates the hydrogen bonding force of the resin, δD C Indicates the dispersion power of the sensitizing component or the luminescent component, δP C Indicates the permanent dipole intermolecular force of the sensitizing component or the luminescent component, δH C Indicates the hydrogen bonding force of the sensitizing component or the luminescent component.

[0094] A-4. Sensitizing component and luminescent component

[0095] A-4-1. Sensitizing ingredients

[0096] It is obvious from the mechanism described in item A-1 that the sensitizing component absorbs light (incident light) and becomes an excited triplet state by intersystem crossing from an excited singlet state, while causing triplet-triplet energy transfer to occur in the luminescent component. Examples of sensitizing components include compounds having a porphyrin structure, a phthalocyanine structure or a fullerene structure. The compound may also contain a metal atom in the molecule. Examples of metal atoms include Pt, Pd, Zn, Ru, Re, Ir, Os, Cu, Ni, Co, Cd, Au, Ag, Sn, Sb, Pb, P, and As. Pt, Pd, and Os are preferred. In addition, specific examples of compounds that can function as sensitizing components will be described in item A-4-3 later.

[0097] The sensitizing component may also be a quantum dot. The quantum dot may be formed of any appropriate material. The quantum dot may preferably be formed of an inorganic material, more preferably of an inorganic conductor material or an inorganic semiconductor material. Semiconductor materials include, for example, II-VI, III-V, IV-VI and IV semiconductors. Specific examples include: Si, Ge, Sn, Se, Te, B, C (including diamond), P, BN, BP, BAs, AlN, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb, InN, InP, InAs, InSb, AlN, AlP, AlAs, AlSb, GaN, GaP, GaAs, GaSb, ZnO, ZnS, ZnSe, ZnTe, CdS, CdSe, CdSeZ n, CdTe, HgS, HgSe, HgTe, BeS, BeSe, BeTe, MgS, MgSe, GeS, GeSe, GeTe, SnS, SnSe, SnTe, PbO, PbS, PbSe, PbTe, CuF, CuCl, CuBr, CuI, Si3N4, Ge3N4, Al2O3, (Al, Ga, In)2(S, Se, Te)3, Al2CO and combinations (complexes) thereof.

[0098] The sensitizing component is contained in the up-conversion film in the following ratio: preferably 7.00×10 -9 mol~5.00×10 -6 mol, preferably 1.00×10 -8 mol~3.00×10 -6 mol, more preferably 4.50×10 - 8 mol~2.00×10 -6If the content of the sensitizing component is too low, sufficient triplet excitons may not be generated, resulting in insufficient efficiency in achieving triplet-triplet annihilation. If the content of the sensitizing component is too high, the efficiency may become insufficient due to triplet-triplet annihilation between molecules of the sensitizing component or reabsorption of upconversion luminescence energy.

[0099] A-4-2. Luminescent components

[0100] It is obvious from the mechanism described in item A-1 that the luminescent component receives the movement of triplet-triplet energy from the sensitizing component to generate an excited triplet state, and at the same time, triplet-triplet annihilation occurs through the diffusion and collision of the luminescent component molecules in the excited triplet state, generating an excited singlet state of a higher energy level. As luminescent components, various compounds with condensed aromatic rings are known. Specific examples include compounds with naphthalene structure, onion structure, pyrene structure, perylene structure, tetracene structure, fluoroboron dipyrrole (Bodipy) structure (boron dipyrromethene (borondipyrromethene) structure), and pyrrolopyrrole diketo structure. In addition, specific examples of compounds that can function as luminescent components will be described in item A-4-3 later.

[0101] The luminescent component is contained in the up-conversion film in the following ratio: preferably 5.00×10 -6 mol~7.00×10 -5 mol, preferably 6.00×10 -6 mol~6.00×10 -5 mol, more preferably 7.00×10 - 6 mol~5.00×10 -5 If the content of the luminescent component is too low, the distance between the molecules of the luminescent component may become larger, so that the triplet excitons received from the sensitizing dye cannot diffuse between the molecules of the luminescent component. If the content of the luminescent component is too high, it may be deactivated due to concentration quenching.

[0102] The blending ratio of the sensitizing component to the luminescent component (sensitizing component: luminescent component) (molar ratio) is preferably 1:10 to 1:7000, more preferably 1:25 to 1:3000, further preferably 1:30 to 1:200, and particularly preferably 1:35 to 1:100. When the blending ratio is within the above range, triplet excitons generated from the sensitizing component efficiently move to the luminescent pigment, and deactivation between luminescent pigments is suppressed as much as possible, so that triplet-triplet annihilation can be well achieved.

[0103] A-4-3. Combination of sensitizing component and luminescent component

[0104] Preferred combinations of sensitizing components and luminescent components corresponding to the wavelengths of incident light and up-converted light are as follows.

[0105] The sensitizing component that absorbs light in the wavelength region λ1 of 510 nm to 550 nm is the following compound, and the luminescent component that emits (luminesces) light in the wavelength region λ2 of 400 nm to 500 nm is the following compound. This combination can up-convert green light into blue light.

[0106] <sensitizing ingredient>

[0107] [Chemical formula 14]

[0108]

[0109] <Luminous Components>

[0110] [Chemical formula 15-1]

[0111]

[0112] [Chemical formula 15-2]

[0113]

[0114] The sensitizing component that absorbs light in the wavelength region λ1 of 610 nm to 650 nm is the following compound, and the luminescent component that emits (luminesces) light in the wavelength region λ2 of 500 nm to 600 nm is the following compound. This combination can up-convert red light into yellow-green light.

[0115] <sensitizing ingredient>

[0116] [Chemical formula 16]

[0117]

[0118] <Luminous Components>

[0119] [Chemical formula 17]

[0120]

[0121] The sensitizing component that absorbs light in the wavelength region λ1 of 700 nm to 810 nm is the following compound, and the luminescent component that emits (luminesces) light in the wavelength region λ2 of 500 nm to 700 nm is the following compound. This combination can up-convert near infrared light into visible light (red to green light).

[0122] <sensitizing ingredient>

[0123] [Chemical formula 18]

[0124]

[0125] <Luminous Components>

[0126] [Chemical formula 19]

[0127]

[0128] [Chemical formula 20]

[0129]

[0130] The sensitizing component that absorbs light in the wavelength region λ1 of 700 nm to 730 nm is the following compound, and the luminescent component that emits (luminesces) light in the wavelength region λ2 of 400 nm to 500 nm is the following compound. This combination can up-convert near infrared light into visible light (blue light).

[0131] <Sensitizing ingredient>

[0132] [Chemical formula 21]

[0133]

[0134] <Luminous Components>

[0135] [Chemical formula 22]

[0136]

[0137] The sensitizing component that absorbs light in the wavelength region λ1 of 410 nm to 500 nm is the following compound, and the luminescent component that emits (luminesces) light in the wavelength region λ2 of 300 nm to 400 nm is the following compound. This combination can up-convert blue light into ultraviolet light.

[0138] <sensitizing ingredient>

[0139] [Chemical formula 23]

[0140]

[0141] <Luminous Components>

[0142] [Chemical formula 24]

[0143]

[0144] The sensitizing component that absorbs light in the wavelength region λ1 near 630nm to 640nm (e.g. 635nm) is a quantum dot (CdSe, CdSe / ZnS), and the luminescent component that emits (luminesces) light in the wavelength region λ2 near 440nm to 460nm (e.g. 450nm) is the following compound. This combination can up-convert near-infrared light into visible light (blue light).

[0145] <Luminous Components>

[0146] [Chemical formula 25]

[0147]

[0148] The sensitizing component that absorbs light in the wavelength region λ1 near 970nm to 990nm (e.g. 980nm) is a quantum dot (PbSe, PbS / CdS), and the luminescent component that emits (luminesces) light in the wavelength region λ2 near 550nm to 570nm (e.g. 560nm) is the following compound. This combination can up-convert near-infrared light into visible light (green light).

[0149] <Luminous Components>

[0150] [Chemical formula 26]

[0151]

[0152] B. Method for manufacturing upconversion film

[0153] A typical example of a method for producing an upconversion thin film will be described. Specifically, an embodiment using an oil-in-water (O / W) emulsion and an embodiment using a water-in-oil (W / O) emulsion will be described.

[0154] B-1. Embodiment using O / W type emulsion

[0155] The manufacturing method of this embodiment includes the following steps: preparing an oil-in-water emulsion from an aqueous solution of a water-soluble resin and an oily solvent solution or oily solvent dispersion of a sensitizing component and a luminescent component (hereinafter sometimes collectively referred to as "oily solvent solution, etc."); applying the oil-in-water emulsion on a substrate to form a coating film; drying the coating film; and applying external force and / or heat to the dried coating film to form a thin film, the thin film having a matrix and a void portion formed by the water-soluble resin, and the sensitizing component and the luminescent component are present at the interface between the matrix and the void portion. Each step is described in detail below.

[0156] <Preparation of emulsion>

[0157] The water-soluble resin is as described in the above-mentioned item A-3. The concentration of the aqueous solution can be, for example, 3% to 20% by weight, and can be, for example, 5% to 10% by weight. The sensitizing component and the luminescent component are each as described in the above-mentioned item A-4. For example, a volatile solvent can be used as the oily solvent. Specific examples of the solvent include: esters such as ethyl acetate, butyl acetate, and propyl acetate; aromatic hydrocarbons such as toluene and benzene; alicyclic hydrocarbons such as cyclohexane, cyclopentanone, and methylcyclohexane; aliphatic hydrocarbons such as hexane; ketones such as methyl ethyl ketone; halogenated hydrocarbons such as chloroform and dichloromethane, etc. The concentration of the sensitizing component in the oily solvent solution can be, for example, 0.001mM to 1mM, and the concentration of the luminescent component can be, for example, 1mM to 50mM. The aqueous solution of the water-soluble resin and the oily solvent solution of the sensitizing component and the luminescent component are mixed in such a manner that the blending amount of the sensitizing component and the luminescent component relative to the water-soluble resin (matrix resin) becomes the desired range described in the above-mentioned item A-4. The amount of the mixed aqueous solution and the amount of the oily solvent solution etc. can be adjusted by adjusting the concentration of the water-soluble resin in the aqueous solution, the concentration of the sensitizing component and the concentration of the luminescent component in the oily solvent solution etc. As a result, the concentration (e.g., volume fraction) and size of the oil droplets (hereinafter, sometimes referred to as emulsion particles) in the emulsion can be adjusted, and thus the porosity and the size of the pores (holes) of the obtained upconversion film can be adjusted.

[0158] The emulsion can be prepared by any appropriate method. For example, an aqueous solution of a water-soluble resin is mixed with an oily solvent solution of a sensitizing component and a luminescent component, and the mixed solution is emulsified using a homogenizer, thereby preparing an emulsion. The obtained emulsion can also be defoamed as required. The volume fraction of the emulsion particles can be, for example, 2% to 25%. If the volume fraction of the emulsion particles is within the range, an upconversion film with a desired porosity can be obtained. The average particle size of the emulsion particles can be, for example, 0.2μm to 400μm. If the average particle size of the emulsion particles is within the range, an upconversion film with a desired void (pore) size can be obtained.

[0159] <Film Formation and Drying>

[0160] Next, the emulsion obtained above is applied to a substrate to form a coating film. The substrate typically includes a resin sheet or glass. Any appropriate resin can be used as the resin forming the resin sheet. Specific examples include: cellulose resins such as polyimide resins, triacetyl cellulose (TAC), or transparent resins such as polyester, polyvinyl alcohol, polycarbonate, polyamide, polyethersulfone, polysulfone, polystyrene, polynorbornene, polyolefin, (meth) acrylic acid, and acetate. In addition, thermosetting resins or ultraviolet curing resins such as (meth) acrylic acid, urethane, (meth) acrylic acid urethane, epoxy, and silicone can also be listed. In addition, glassy polymers such as siloxane polymers can also be listed. Any appropriate method can be used for the coating method. Specific examples include: roller coating, spin coating, wire rod coating, dip coating, die coating, curtain coating, spray coating, and knife coating (comma coating, etc.). Furthermore, a drum film-forming machine can also be used to form the coating film. In this case, the film-forming roller (drying roller) of the drum film-forming machine can function as a substrate. The film-forming roller (drying roller) is formed of, for example, a metal such as nickel, chromium, copper, iron, stainless steel, etc. The temperature of the emulsion during coating can be, for example, 10°C to 60°C. The thickness of the coating film is adjusted so that the thickness of the obtained up-conversion film is within the desired range described in the above-mentioned item A-2 (for example, 5μm to 200μm). The thickness of the coating film can be, for example, 100μm to 1000μm.

[0161] Next, the coating is dried. Drying can be performed by any appropriate means (e.g., an oven). The drying temperature can be, for example, 60° C. to 90° C., and the drying time can be, for example, 20 minutes to 60 minutes. By drying, a dry coating having substantially the same thickness as the obtained upconversion film can be obtained. The dried coating can typically be cooled naturally to room temperature.

[0162] <Formation of Upconversion Thin Film>

[0163] Finally, an external force and / or heat is applied to the dry coating to form an upconversion film. By applying an external force and / or heat to the dry coating, a void portion is formed, and a sensitizing component and a luminescent component are configured at the interface between the matrix formed by the water-soluble resin and the void portion. The external force and / or heat can be applied by any appropriate means. Among them, as a specific example of applying an external force, it can be listed as follows: peeling, shearing, cutting, bending, vibrating, and decompressing the dry coating from the substrate. In addition, an electric field or a magnetic field can also be applied. According to this embodiment, by peeling the dry coating from the substrate, a void portion is automatically formed, and a sensitizing component and a luminescent component are configured at the interface between the matrix formed by the water-soluble resin and the void portion, so further operations and / or steps for applying external force can be omitted. The formation of the void portion by applying an external force and the configuration of the sensitizing component and the luminescent component at the interface between the matrix and the void portion are presumably due to the following mechanism: as described above, by drying the coating of the emulsion, the thickness can be less than 1 / 10. As a result, the emulsion particles will be in a compressed state. This is presumed from the fact that the dry coating film before being peeled off from the substrate shows a uniform state in the microscope image ( Figure 2 ), and the coating film is transparent under visual observation. In addition, the sensitizing component and the luminescent component are essentially present only in the emulsion particles in the emulsion, and even if the emulsion particles are compressed in the dry coating film, they will not move into the resin (matrix), but will remain in the compressed emulsion particles. If an external force is applied in this state (for example, if the dry coating film is peeled off from the substrate), the pressure is released, and the compressed emulsion particles become a foaming state, and bubbles (voids) are formed. The formation of bubbles (voids) by peeling can be seen from Figure 2 The microscopic image of the film is confirmed. By forming bubbles (voids) in this way, an interface between the bubbles (voids) and the matrix is ​​formed. As described above, the sensitizing component and the luminescent component will remain in the compressed emulsion particles, so the sensitizing component and the luminescent component will adhere to the interface due to the formation of the interface. By proceeding in the above manner, a film can be obtained, which has a matrix and a void portion formed by a water-soluble resin, and the sensitizing component and the luminescent component are present at the interface between the matrix and the void portion. In addition, the above mechanism is only a speculation, does not deny the possibility of other mechanisms, and does not limit the present invention.

[0164] B-2. Embodiment using W / O type emulsion

[0165] The manufacturing method of this embodiment includes the following steps: preparing an oil-in-water emulsion from an oily solvent solution of an oil-soluble resin and an aqueous dispersion of a sensitizing component and a luminescent component; applying the oil-in-water emulsion on a substrate to form a coating film; drying the coating film; and forming a thin film by the drying, the thin film having a matrix and a void portion formed by the oil-soluble resin, and the sensitizing component and the luminescent component are present at the interface between the matrix and the void portion. The oil-soluble resin is as described in the above-mentioned item A-3. The oily solvent solution of the oil-soluble resin and the aqueous dispersion of the sensitizing component and the luminescent component are mixed in such a manner that the blending amount of the sensitizing component and the luminescent component relative to the oil-soluble resin (matrix resin) is within the desired range described in the above-mentioned item A-4. Examples of the oily solvent include aliphatic hydrocarbons such as n-hexane and n-heptane; alicyclic hydrocarbons such as cyclohexane, methylcyclohexane, and ethylcyclohexane; aromatic hydrocarbons such as benzene, toluene, and xylene; esters such as methyl acetate, ethyl acetate, butyl acetate, isobutyl acetate, propyl acetate, and isoamyl acetate; ketones such as methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone, and cyclohexanone; and halogenated hydrocarbons such as dichloromethane, chloroform, chlorobenzene, and dichlorobenzene. The amount of the mixed aqueous solution and the amount of the oily solvent solution can be adjusted by adjusting the concentration of the oil-soluble resin in the oily solvent solution, the concentration of the sensitizing component in the aqueous dispersion, and the concentration of the luminescent component. As a result, the concentration (e.g., volume fraction) and size of the water droplets (emulsion particles) in the emulsion can be adjusted, and thus the porosity and the size of the pores (holes) of the obtained upconversion film can be adjusted. The W / O type emulsion of this embodiment is formed by using a sensitizing component and a luminescent component that are insoluble in an oily solvent and water, so that the sensitizing component and the luminescent component in a solid state are aggregated between the oily solvent and water droplets to function as a surfactant. As a result, unlike the O / W type emulsion described in Item B-1, a void portion can be formed without applying external force and / or heat to the dried coating film, and the sensitizing component and the luminescent component can be arranged at the interface between the matrix formed by the oil-soluble resin and the void portion.

[0166] Example

[0167] Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited to these examples. In addition, "parts" and "%" in the examples are by weight unless otherwise specified.

[0168] <Example 1>

[0169] 1. Preparation of oily solvent solutions of sensitizing components and luminescent components

[0170] Meso-tetraphenyl-tetraanthraporphyrin palladium (PdTPTAP: the following chemical formula) is used as a sensitizing component, and rubrene (the following chemical formula) is used as a luminescent component. In a glove box, a toluene solution of rubrene and PdTPTAP is prepared. The concentration of PdTPTAP in the solution is set to 0.554 mM, and the concentration of rubrene is set to 20 mM. That is, the molar ratio of the sensitizing component: the luminescent component is set to 1:36. The prepared solution is sealed and stored in a vial until the emulsification step.

[0171] <sensitizing ingredient>

[0172] [Chemical formula 27]

[0173]

[0174] <Luminous Components>

[0175] [Chemical formula 28]

[0176]

[0177] 2. Preparation of Emulsion

[0178] 0.4 ml of the above solution was added to 5 g of polyvinyl alcohol (PVA) aqueous solution (9%). The amount of solution added to 1 g of PVA was 0.89 ml, and the amount (concentration) of the sensitizing component to 1 g of PVA was 4.92 × 10 -7 mol and the luminescent component amount (concentration) is 1.78×10 -5 mol. The solution was injected through a tube with an inner diameter of 0.75 mm while being stirred with a homogenizer (17500 rpm) until the whole was emulsified. Argon was blown into the obtained emulsion for about 2 minutes, and a stirrer (THINK Y) was used to stir for 3 minutes in a defoaming mode (2200 rpm) and for 7 minutes in a mixing mode (2000 rpm). An O / W type emulsion was prepared in the above manner. It should be noted that PVA with a degree of polymerization of 1700 and a saponification degree of 95.5% to 97.5% was used.

[0179] 3. Formation of upconversion film

[0180] Use an applicator to apply the above-obtained O / W type emulsion on a polyimide film (substrate) with a coating thickness of 700 μm. Dry the coating / polyimide film laminate in a constant temperature oven. The drying temperature is 80°C and the drying time is 30 minutes. After drying, the laminate is naturally cooled to room temperature. Finally, the dried coating is peeled off from the polyimide film to obtain an upconversion film (thickness 47 μm). According to SEM observation, the obtained film is a porous film with voids formed by a bubble structure. In addition, the steps after the preparation of the emulsion are carried out in the air in a dark place (under a darkroom light only).

[0181] <Optical Evaluation>

[0182] The obtained film was irradiated with a wavelength of 810 nm and a temperature of 110 mW / cm 2 , irradiate with a laser of 1.2 mm in diameter. The excitation light density is adjusted with an ND filter at 5 W / cm 2 The measurement was performed within the following range. The upconversion luminescence was detected by a spectrometer through an optical fiber, and the detection range was set to include the entire laser diameter. As a result, upconversion luminescence with a peak wavelength of about 560nm was observed. The luminescence peak integral value (500nm to 730nm) was 778 times that of the film of Comparative Example 1 described later.

[0183] <Evaluation of Porous Structure>

[0184] The surface density of the obtained film was obtained by measuring the weight of the test sample punched into a predetermined shape with an electronic balance and dividing it by the area of ​​the main surface of the test sample. The result was 0.0041 g / cm 2 The density was obtained by measuring the weight of the test sample punched into a predetermined shape with an electronic balance and dividing it by the volume of the test sample. The result was 0.8772 g / cm 3 . The porosity and average particle size are obtained by using the difference in brightness between the pores and the resin part of the cross-sectional SEM image, using image analysis software (Image J) for image analysis, and performing binarization to extract the pores. The particle size is defined as the equivalent circle diameter, which is the diameter of a circle corresponding to the area of ​​the extracted pores, and the average particle size is calculated. As a result, the average particle size is 0.8 μm. In addition, the volume of the particles is calculated using the equivalent circle diameter of a sphere having the same diameter as the particles. The porosity is calculated by dividing the total volume of the obtained particles by the area of ​​the main surface of the cross-sectional SEM image. As a result, the porosity is 40%.

[0185] <Evaluation of the Existence Positions of Sensitizing Components and Luminescent Components>

[0186] The obtained film was cut by ultrathin microtome under freezing condition (about -60°C) to prepare cross section, and then TOF-SIMS analysis was performed. Bi3 2+ Primary ion irradiation to the film cross section (irradiation dose: 2.8×10 12 ions / cm 2 ), and observe the marked 40 μm square portion at an acceleration voltage of 30 kV. More specifically, the marked portion is imaged, the index ions of the sensitizing component and the luminescent component (hereinafter referred to as the dye) are set to m / z 586, and the color is used to distinguish it from other portions, thereby obtaining a two-dimensional image. More specifically, in the two-dimensional image, the dye portion is set to green, and the other portions are set to red.

[0187] Moreover, after the cross section (marked portion) obtained by the ultrathin slicer of the above-mentioned film was subjected to conductive treatment, a secondary electron image of the cross section was obtained by a field emission scanning electron microscope (FE-SEM, manufactured by Hitachi, SU-8220) at an accelerating voltage of 2 kV. The magnification of the secondary electron image was adjusted to be the same as the magnification of the two-dimensional image obtained by TOF-SIMS analysis. The void portion present in the cross section of the film was confirmed in the secondary electron image.

[0188] Next, the two-dimensional image obtained by TOF-SIMS analysis was superimposed on the secondary electron image obtained by SEM to confirm the relative positional relationship between the dye part and the void part. The result showed that the dye part was located at a position overlapping with the void part. Thus, it was confirmed that the sensitizing component and the luminescent component existed at the interface between the matrix and the void part.

[0189] <Example 2>

[0190] A diketopyrrolopyrrole (DPP) derivative (chemical formula below) was used as a light-emitting component instead of rubrene, and the amount (concentration) of the sensitizing component was set to 4.92×10 -7 mol and the luminescent component amount (concentration) is set to 4.92×10 -5 mol (i.e., the molar ratio of the sensitizing component to the luminescent component was set to 1:100), and an upconversion film (thickness 51 μm) was obtained in the same manner as in Example 1. The obtained film was subjected to the same evaluation as in Example 1. As a result, upconversion luminescence with a peak wavelength of about 630 nm was observed. The surface density of the obtained film was 0.0045 g / cm 2 , density is 0.8775g / cm 3The integrated value of the luminescence peak (500 nm to 730 nm) was four times that of the film of Comparative Example 1 described later.

[0191] <Luminous Components>

[0192] [Chemical formula 29]

[0193]

[0194] <Example 3>

[0195] Octaethylporphyrin platinum (PtOEP: chemical formula) was used as a sensitizing component, and diphenylonium (DPA: chemical formula below) was used as a luminescent component. The amount (concentration) of the sensitizing component was set to 2.39×10 -7 mol, the luminescent component amount (concentration) is set to 4.78×10 -5 mol (ie, the molar ratio of the sensitizing component: the luminescent component is set to 1:200). The solutions of the sensitizing component and the luminescent component are prepared in air. Except for these, an upconversion thin film (thickness 44 μm) is obtained in the same manner as in Example 1.

[0196] <sensitizing ingredient>

[0197] [Chemical formula 30]

[0198]

[0199] <Luminous Components>

[0200] [Chemical formula 31]

[0201]

[0202] The obtained film was irradiated with a laser beam of 532 nm wavelength, 174 mW, and 100 μm diameter. The excitation light density was adjusted with an ND filter at 150 W / cm 2 The measurement was performed within the following range. The upconversion luminescence was detected by a spectrometer through an optical fiber, and the detection range was set to include the entire laser diameter. As a result, upconversion luminescence with a peak wavelength of about 430nm was observed. The surface density of the obtained film was 0.0050g / cm 2 , density is 1.1286g / cm 3 The average particle size was 0.6 μm, the porosity was 39%, and the integrated value of the luminescence peak (400 nm to 510 nm) was 11 times that of the film of Comparative Example 2 described later.

[0203] The obtained thin film was subjected to evaluation of the porous structure and evaluation of the presence positions of the sensitizing component and the light-emitting component in the same manner as in Example 1. The cross-sectional SEM image of the thin film of Example 3 is shown in FIG. Figure 4 . Figure 4 In the above, it was confirmed that the void portion had independent bubbles and a continuous bubble structure in which a plurality of bubbles were connected. More specifically, continuous bubbles having holes connected to other pores and independent bubbles having no holes connected to other pores were confirmed.

[0204] <Example 4>

[0205] An upconversion thin film was obtained in the same manner as in Example 3 except that octaethylporphyrin palladium (PdOEP: the following chemical formula) was used as a sensitizing component. The obtained thin film was subjected to the same evaluation as in Example 3. As a result, upconversion luminescence with a peak wavelength of about 430 nm was observed. The luminescence peak integral value (400 nm to 510 nm) was 5 times that of the thin film of Comparative Example 5 described later.

[0206] <sensitizing ingredient>

[0207] [Chemical formula 32]

[0208]

[0209] <Example 5>

[0210] The upconversion film was obtained in the same manner as in Example 3 except that hydroxyethyl cellulose (HEC) was used instead of PVA. According to SEM observation, the obtained film was a porous film having a void portion formed by a bubble structure. The obtained film was subjected to the same evaluation as in Example 3. As a result, upconversion luminescence with a peak wavelength of about 430 nm was observed. The luminescence peak integral value (400 nm to 510 nm) was 19 times that of the film of Comparative Example 2 described later.

[0211] <Example 6>

[0212] The amount (concentration) of the sensitizing component was set to 1.78×10 -8 mol, the luminescent component amount (concentration) is set to 1.78×10 -5 The up-conversion film was obtained in the same manner as in Example 1 except that the molar ratio of the sensitizing component to the luminescent component was 1:1000. The obtained film was subjected to the same evaluation as in Example 1. As a result, up-conversion luminescence with a peak wavelength of about 560 nm was observed. The luminescence peak integral value (500 nm to 730 nm) was 74 times that of the film of Comparative Example 1 described later.

[0213] <Example 7>

[0214] The amount of solution added to 1 g of PVA (sensitizing component concentration and luminescent component concentration are the same as in Example 1) was set to 2.7 ml. An upconversion film (thickness 68 μm) was obtained in the same manner as in Example 1. The obtained film was subjected to the same evaluation as in Example 1. As a result, upconversion luminescence with a broad peak at about 570 nm to about 600 nm was observed. The surface density of the obtained film was 0.0033 g / cm 2 , density is 0.4804g / cm 3 The average particle size was 1.0 μm and the porosity was 42%. The luminescence peak integral value (500 nm to 730 nm) was 372 times that of the film of Comparative Example 1 described later. In addition, the cross-sectional SEM image of the film of Example 7 is shown in FIG. Figure 5 .exist Figure 5 In, also with Figure 4 Similarly, open cells having pores communicating with other pores and closed cells having no pores communicating with other pores were confirmed.

[0215] <Comparative Example 1>

[0216] An upconversion film (thickness 28 μm) was obtained in the same manner as in Example 1, except that tetrahydrofuran (THF: water-soluble solvent) was used instead of toluene to prepare the solutions of the sensitizing component and the luminescent component. No emulsion was formed during the manufacturing process. According to SEM observation, no bubbles were observed in the obtained film. The obtained film was subjected to the same evaluation as in Example 1. As a result, upconversion luminescence with a peak wavelength of about 560 nm was observed. The surface density of the obtained film was 0.0035 g / cm 2 , density is 1.2362g / cm 3 .

[0217] <Comparative Example 2>

[0218] An upconversion film (thickness 27 μm) was obtained in the same manner as in Example 3, except that tetrahydrofuran (THF: water-soluble solvent) was used instead of toluene to prepare the solutions of the sensitizing component and the luminescent component. No emulsion was formed during the manufacturing process. According to SEM observation, no bubbles were observed in the obtained film. The obtained film was subjected to the same evaluation as in Example 1. As a result, upconversion luminescence with a peak wavelength of about 440 nm was observed. The surface density of the obtained film was 0.0045 g / cm 2 , density is 1.6404g / cm 3 .

[0219] <Up-conversion of low-intensity light to the same degree as sunlight>

[0220] The film of Example 1 was irradiated with a low intensity (2.5 mW / cm 2 ) xenon light. As a result, the following was observed Figure 3 On the other hand, in the thin film of Comparative Example 1, no up-conversion luminescence was observed.

[0221] <Example 8>

[0222] An upconversion film was obtained in the same manner as in Example 3 except that PVA having a degree of polymerization of 1800 and a saponification degree of 83.0% to 86.0% was used. According to SEM observation, the obtained film was a porous film having a void portion formed by a bubble structure. The obtained film was subjected to the same evaluation as in Example 3. As a result, upconversion luminescence with a peak wavelength of about 430 nm was observed. The luminescence peak integral value (400 nm to 510 nm) was 2.6 times that of the film of Comparative Example 2.

[0223] <Example 9>

[0224] An upconversion film was obtained in the same manner as in Example 3, except that PVA having a degree of polymerization of 500 and a saponification degree of 98.0% to 99.0% was used. According to SEM observation, the obtained film is a porous film having voids formed by a bubble structure. The obtained film was subjected to the same evaluation as in Example 3. As a result, upconversion luminescence with a peak wavelength of about 430 nm was observed. The luminescence peak integral value (400nm to 510nm) is 2.6 times that of the film of Comparative Example 2. Moreover, the average particle size of the obtained film is 0.3 μm, and the porosity is 25%.

[0225] <Example 10>

[0226] In addition to using amine modification (NR3 + Cl - )PVA (saponification degree 85.5% to 88.0%) was used as PVA, and an upconversion film was obtained in the same manner as in Example 3. According to SEM observation, the obtained film is a porous film with voids formed by a bubble structure. The obtained film was subjected to the same evaluation as in Example 3. As a result, upconversion luminescence with a peak wavelength of about 430nm was observed. The luminescence peak integral value (400nm to 510nm) was 3.5 times that of the film of Comparative Example 2.

[0227] <Example 11>

[0228] The upconversion film was obtained in the same manner as in Example 3 except that carboxylic acid-modified (carboxyl group-introduced) PVA (saponification degree 96.5% or more) was used as PVA. According to SEM observation, the obtained film is a porous film having voids formed by a bubble structure. The obtained film was subjected to the same evaluation as in Example 3. As a result, upconversion luminescence with a peak wavelength of about 430 nm was observed. The luminescence peak integral value (400 nm to 510 nm) was 5.4 times that of the film of Comparative Example 2.

[0229] <Example 12>

[0230] An upconversion film was obtained in the same manner as in Example 3, except that poly(sodium 4-styrenesulfonate) (manufactured by Sigma-Aldrich, molecular weight ~1000000) was used instead of PVA. According to SEM observation, the obtained film is a porous film having voids formed by a bubble structure. The obtained film was subjected to the same evaluation as in Example 3. As a result, upconversion luminescence with a peak wavelength of about 430nm was observed. The luminescence peak integral value (400nm~510nm) is 3.5 times that of the film of Comparative Example 2. Moreover, the average particle size of the obtained film is 0.6μm, and the porosity is 16%.

[0231] <Example 13>

[0232] An upconversion film was obtained in the same manner as in Example 3 except that polyethylene oxide (manufactured by Wako Pure Chemical Industries, Ltd., molecular weight 50,000) was used instead of PVA. According to SEM observation, the obtained film is a porous film having a void portion formed by a bubble structure. The obtained film was subjected to the same evaluation as in Example 3. As a result, upconversion luminescence with a peak wavelength of about 430 nm was observed. The luminescence peak integral value (400 nm to 510 nm) was 2.3 times that of the film of Comparative Example 2.

[0233] <Example 14>

[0234] 1. Preparation of oily solvent solutions of sensitizing components and luminescent components

[0235] A water-soluble TPP derivative (chemical formula below) was used as a sensitizing component, and a water-soluble DPA derivative (chemical formula below) was used as a luminescent component. 296 μg of TPP derivative and 28.2 mg of DPA derivative were placed in a test tube, 2.61 mL of a 1% toluene solution of a nonionic surfactant (Span80) was added, and stirred with a homogenizer. 1.05 mL of water was further added and stirred with a homogenizer to prepare an emulsion.

[0236] <sensitizing ingredient>

[0237] [Chemical formula 33]

[0238]

[0239] <Luminous Components>

[0240] [Chemical formula 34]

[0241]

[0242] 2. Preparation of Emulsion

[0243] The total amount of the above-obtained emulsion was added to a vial containing 5.23 g of a toluene solution (20%) of polymethyl methacrylate (PMMA), and stirred with a homogenizer to prepare a W / O type emulsion. The amount (concentration) of the sensitizing component relative to 1 g of PMMA was 2.39 × 10 -7 mol and the luminescent component amount (concentration) is 4.78×10 -5 That is, the molar ratio of the sensitizing component to the luminescent component is 1:200.

[0244] 3. Formation of upconversion film

[0245] The W / O type emulsion obtained above was drop-coated on glass (substrate). The coating / glass laminate was dried while blowing nitrogen, and further vacuum dried in a dryer. Finally, the dried coating was peeled off from the glass to obtain an upconversion film (thickness 38 μm). According to SEM observation, the obtained film was a porous film with voids formed by a bubble structure.

[0246] <Optical Evaluation>

[0247] The obtained film was placed in a groove and sealed in an argon atmosphere to serve as a measurement sample. This measurement sample was subjected to the same evaluation as in Example 3. As a result, upconversion luminescence with a peak wavelength of about 460 nm was observed. The luminescence peak integral value (400 nm to 510 nm) was 3.0 times that of Comparative Example 3 described later.

[0248] <Comparative Example 3>

[0249] The upconversion film was obtained in the same manner as in Example 14 except that the suspension of the sensitizing component and the luminescent component was prepared without adding water. No emulsion was formed during the manufacturing process. According to SEM observation, no bubbles were observed in the obtained film. The obtained film was subjected to the same evaluation as in Example 14. As a result, upconversion luminescence with a peak wavelength of about 460 nm was observed.

[0250] <Example 15>

[0251] An upconversion film was obtained in the same manner as in Example 14 except that a toluene solution (15%) of polystyrene (PS) was used instead of a toluene solution (20%) of PMMA. According to SEM observation, the obtained film is a porous film having voids formed by a bubble structure. The obtained film was subjected to the same evaluation as in Example 14. As a result, upconversion luminescence with a peak wavelength of about 460 nm was observed. The luminescence peak integral value (400 nm to 510 nm) is 35.9 times that of Comparative Example 4 described later.

[0252] <Comparative Example 4>

[0253] The up-conversion film was obtained in the same manner as in Example 15 except that the suspension of the sensitizing component and the luminescent component was prepared without adding water. No emulsion was formed during the manufacturing process. According to SEM observation, no bubbles were observed in the obtained film. The obtained film was subjected to the same evaluation as in Example 14. As a result, up-conversion luminescence having peaks at about 460 nm and about 510 nm (maximum) was observed.

[0254] <Example 16>

[0255] The amount of solution added to 1 g of PVA (sensitizing component concentration and luminescent component concentration are the same as in Example 1) was set to 0.22 ml. An upconversion film (thickness 29 μm) was obtained in the same manner as in Example 1. The obtained film was subjected to the same evaluation as in Example 1. As a result, upconversion luminescence with a broad peak at about 570 nm to about 600 nm was observed. The surface density of the obtained film was 0.0043 g / cm 2 , density is 1.4966g / cm 3 The average particle size was 1.0 μm, the porosity was 7%, and the integrated value of the luminescence peak (500 nm to 730 nm) was 39 times that of the film of Comparative Example 1.

[0256] <Comparative Example 5>

[0257] The up-conversion film was obtained in the same manner as in Example 4 except that tetrahydrofuran (THF: water-soluble solvent) was used instead of toluene to prepare the solution of the sensitizing component and the luminescent component. No emulsion was formed during the manufacturing process. According to SEM observation, no bubbles were observed in the obtained film. The obtained film was subjected to the same evaluation as in Example 1. As a result, up-conversion luminescence with a peak wavelength of about 440 nm was observed.

[0258] <Example 17>

[0259] An upconversion film was obtained in the same manner as in Example 1 except that the PdTPTAP concentration in the solution was set to 0.1 mM (i.e., the molar ratio of the sensitizing component: the luminescent component was set to 1:200). The obtained film was subjected to the same evaluation as in Example 1. As a result, upconversion luminescence with a peak wavelength of about 560 nm was observed. The luminescence peak integral value (500 nm to 730 nm) was 616 times that of the film of Comparative Example 1.

[0260] <Example 18>

[0261] An upconversion film was obtained in the same manner as in Example 1 except that meso-tetraphenyl-tetraanthraporphyrin platinum (PtTPTAP: the following chemical formula) was used as a sensitizing component. The obtained film was subjected to the same evaluation as in Example 1. As a result, upconversion luminescence with a peak wavelength of about 560 nm was observed. The luminescence peak integral value (500 nm to 730 nm) was 80 times that of the film of Comparative Example 1.

[0262] [Chemical formula 35]

[0263]

[0264] <Example 19>

[0265] A diphenylonion derivative (DPA2: the following chemical formula) was used as the luminescent component, and the amount (concentration) of the sensitizing component was set to 1.20×10 -6 mol and the luminescent component amount (concentration) is set to 2.39×10 -4 An upconversion film was obtained in the same manner as in Example 3 except that the molar ratio of the sensitizing component to the luminescent component was 1:200. The obtained film was subjected to the same evaluation as in Example 3. The luminescence peak integral value (400 nm to 510 nm) was 9 times that of the film in Comparative Example 3.

[0266] [Chemical formula 36]

[0267]

[0268] <Confirmation of ultra-low temperature upconversion (UC) luminescence>

[0269] After the upconversion film of each example shown in Table 1 was immersed in liquid nitrogen for 2 to 3 minutes, the upconversion film immersed in liquid nitrogen was irradiated with a laser having a wavelength shown in Table 1. In addition, the laser with a wavelength of 810 nm was 8600 mW / cm 2 , irradiation diameter 1.2mm, wavelength 532nm laser 135mW / cm 2 , irradiation diameter 1.0 mm. The presence or absence of up-conversion luminescence was visually confirmed. As a result, up-conversion luminescence (ultra-low temperature UC luminescence) was observed in the up-conversion thin film of each example. The presence or absence and color of ultra-low temperature UC luminescence are shown in Table 1.

[0270] <Confirmation of high-temperature upconversion (UC) luminescence>

[0271] The upconversion film of each embodiment shown in Table 1 is arranged on a cover glass and heated on a heating plate heated to 180°C for 1 minute. After that, the upconversion film on the heating plate is irradiated with a laser having a wavelength shown in Table 1 (the same as confirming the extremely low temperature UC luminescence). The presence or absence of upconversion luminescence is visually confirmed. As a result, upconversion luminescence (high temperature UC luminescence) is observed in the upconversion film of each embodiment. The presence or absence of high temperature UC luminescence is shown in Table 1. That is, it has been confirmed that the upconversion film of the embodiment can perform UC luminescence at high temperature (180°C), room temperature (25°C) and extremely low temperature (-196).

[0272] <Reference Example 1>

[0273] The toluene solution of rubrene and PdTPTAP obtained in "1. Preparation of an oily solvent solution of a sensitizing component and a luminescent component" in Example 1 was confirmed to have UC luminescence at room temperature (25°C) and very low temperature (-196°C) in the same manner as above. It was confirmed that the toluene solution of rubrene and PdTPTAP had UC luminescence at room temperature (25°C), but no UC luminescence was confirmed at very low temperature (-196°C).

[0274] <Reference Example 2>

[0275] Octaethylporphyrin palladium (PdOEP) as a sensitizing component and diphenylonium (DPA) as a luminescent component were dissolved in N,N-dimethylformamide (DMF: a water-soluble solvent) in a molar ratio of sensitizing component:luminescent component of 1:200 to prepare a DMF solution of PdOEP and DPA. The presence or absence of UC luminescence at room temperature (25°C) and extremely low temperature (-196°C) was confirmed in the same manner as above for the DMF solution of PdOEP and DPA. It was confirmed that the DMF solution of PdOEP and DPA had UC luminescence at room temperature (25°C), but no UC luminescence was confirmed at extremely low temperature (-196°C).

[0276] [Table 1]

[0277] Table 1

[0278]

[0279] Industrial Applicability

[0280] The photon up-conversion film according to the embodiment of the present invention is suitable for use in solar cells, solar power generation, photocatalysts, bioimaging, optical devices, and the like.

Claims

1. A photon upconversion film having a matrix and a void portion formed of a resin, and comprising at least: a sensitizing component that absorbs light in a first wavelength region λ1; and A luminescent component that can emit light in a second wavelength region λ2 having a shorter wavelength than the first wavelength region λ1; The sensitizing component and the luminescent component exist at the interface between the matrix and the void portion. 2 . The photon up-conversion film according to claim 1 , wherein the porosity thereof is 5.0 volume % to 60.0 volume %.

3. The photon up-conversion film according to claim 1 or 2, wherein: The void portion has independent cells and a continuous cell structure in which a plurality of cells are continuous.

4. The photon up-conversion film according to claim 1 or 2, wherein: The resin is a water-soluble resin selected from polystyrene sulfonate, polyethylene oxide, polyethyleneimine, polyvinyl alcohol resin and cellulose resin.

5. The photon up-conversion film according to claim 1 or 2, wherein: The resin is an oil-soluble resin selected from (meth)acrylic resins and polystyrene.

6. The photon up-conversion film according to claim 1 or 2, comprising 7.00×10 -9 mol~5.00×10 -6 mol of the sensitizing component, and 5.00×10 -6 mol~7.00×10 - 5 mol of the luminescent component.

7. The photon up-conversion film according to claim 1 or 2, wherein: The first wavelength region λ1 is 510 nm to 550 nm, the second wavelength region λ2 is 400 nm to 500 nm, the sensitizing component is the following compound, and the luminescent component is the following compound: <sensitizing ingredient> <Luminous Components> 。 8. The photon up-conversion film according to claim 1 or 2, wherein: The first wavelength region λ1 is 610 nm to 650 nm, the second wavelength region λ2 is 500 nm to 600 nm, the sensitizing component is the following compound, and the luminescent component is the following compound: <sensitizing ingredient> <Luminous Components> 。 9. The photon up-conversion film according to claim 1 or 2, wherein: The first wavelength region λ1 is 700 nm to 810 nm, the second wavelength region λ2 is 500 nm to 700 nm, the sensitizing component is the following compound, and the luminescent component is the following compound: <sensitizing ingredient> <Luminous Components> 。 10. The photon up-conversion film according to claim 1 or 2, wherein: The first wavelength region λ1 is 700 nm to 730 nm, the second wavelength region λ2 is 400 nm to 500 nm, the sensitizing component is the following compound, and the luminescent component is the following compound: <sensitizing ingredient> <Luminous Components> 。 11. The photon up-conversion film according to claim 1 or 2, wherein: The first wavelength region λ1 is 410 nm to 500 nm, the second wavelength region λ2 is 300 nm to 400 nm, the sensitizing component is the following compound, and the luminescent component is the following compound: <sensitizing ingredient> <Luminous Components> 。 12. The photon up-conversion film according to claim 1 or 2, wherein: The sensitizing component is a quantum dot, and the luminescent component is the following compound: 。 13. The photon up-conversion film according to claim 1 or 2, which can perform up-conversion luminescence in a temperature range of -196°C to 180°C.

14. A method for manufacturing a photon upconversion film, comprising the following steps: An oil-in-water emulsion is prepared from an aqueous solution of a water-soluble resin and an oily solvent solution or oily solvent dispersion of a sensitizing component and a luminescent component; Applying the oil-in-water emulsion on a substrate to form a coating film; allowing the coating to dry; and applying external force and / or heat to the dried coating film to form a thin film, the thin film having a matrix formed of the water-soluble resin and a void portion, and the sensitizing component and the luminescent component are present at the interface between the matrix and the void portion, The sensitizing component can absorb light in the first wavelength region λ1, The light emitting component may emit light in a second wavelength region λ2 having a shorter wavelength than the first wavelength region λ1.

15. A method for manufacturing a photon upconversion film, comprising the following steps: The water-in-oil emulsion is prepared from an oily solvent solution of an oil-soluble resin and an aqueous solution or aqueous dispersion of a sensitizing component and a luminescent component; Applying the water-in-oil emulsion on a substrate to form a coating film; allowing the coating to dry; and By the drying, a thin film is formed, the thin film having a matrix formed of the oil-soluble resin and a void portion, and the sensitizing component and the luminescent component are present at the interface between the matrix and the void portion, The sensitizing component can absorb light in the first wavelength region λ1, The light emitting component may emit light in a second wavelength region λ2 having a shorter wavelength than the first wavelength region λ1.

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