Photon upconversion material and photon upconversion film

Abstract

Provided is a photon upconversion material in which temporal performance degradation is suppressed. A photon upconversion material according to an embodiment of the present invention includes a sensitizing component capable of absorbing light in a first wavelength region λ1, a luminescent component capable of emitting light in a second wavelength region λ2 that is shorter than the first wavelength region λ1, and a dispersion medium, wherein the dispersion medium contains a compound selected from phosphorus-based compounds, sulfur-based compounds, selenium-based compounds, arsenic-based compounds, or tellurium-based compounds, the photon upconversion material contains, with respect to 100 parts by weight of the compound, 1.0×10-5 to 10.0 parts by weight of the sensitizing component and 1.0×10-4 to 50.0 parts by weight of the luminescent component.

Description

Photon upconversion materials and photon upconversion films

[0001] The present invention relates to photon upconversion materials and photon upconversion films.

[0002] Photon upconversion technology, which converts low-energy light into high-energy light, is expected to be applied to various fields such as solar cells or photovoltaic power generation, photocatalysis, bioimaging, and optical devices. A known photon upconversion luminescence in organic materials utilizes triplet-triplet annihilation (TTA), which occurs when triplet-state molecules collide with each other. In photon upconversion materials that utilize TTA, the sensitizing component and / or luminescent component may deteriorate over time, resulting in a decrease in performance, such as photon upconversion efficiency.

[0003] Patent No. 5491408

[0004] The present invention has been made to solve the above-mentioned problems of the prior art, and a main object of the present invention is to provide a photon upconversion material in which deterioration of performance over time is suppressed.

[0005] [1] A photon upconversion material according to an embodiment of the present invention includes a sensitizer capable of absorbing light in a first wavelength region λ1, a light-emitting component capable of emitting light in a second wavelength region λ2 having a wavelength shorter than the first wavelength region λ1, and a dispersion medium; the dispersion medium includes a compound selected from a phosphorus-based compound, a sulfur-based compound, a selenium-based compound, an arsenic-based compound, and a tellurium-based compound; and the photon upconversion material includes a sensitizer component in an amount of 1.0 × 10 with respect to 100 parts by weight of the compound. －５ parts by weight to 10.0 parts by weight of the light-emitting component, and －４The dispersion medium contains from 1 to 50.0 parts by weight. [2] In the above [1], the dispersion medium has an antioxidant function. [3] In the above [1] or [2], the dispersion medium is a phosphorus-based compound or a sulfur-based compound. [4] In any of the above [1] to [3], the dispersion medium is selected from tris(2-ethylhexyl)phosphite, triphenylphosphine, triphenylphosphine, methyldiphenylphosphine, methoxydiphenylphosphine, dimethyl phenylphosphonite, phenoxydiphenylphosphine, tributylphosphine, 4,6-bis(octylthiomethyl)-o-cresol, ditridecyl 3,3'-thiobispropionate, diphenyl sulfide, dibutyl sulfide, diphenyl disulfide, and butyl disulfide. [5] In any of the above [1] to [4], the sensitizing component has an absorption maximum wavelength in the range of 400 nm to 1200 nm. [6] In any of the above [1] to [5], the sensitizing component is a compound having a porphyrin structure, a phthalocyanine structure, a BODIPY structure, a coumarin structure, a quinone structure, a xanthene structure, a fullerene structure, a phenoxazine structure, a phenothiazine structure, an acridone structure, a carbazole structure, or a phenazaborine structure. [7] In any of the above [1] to [6], the light-emitting component has a maximum emission wavelength of 300 nm to 1100 nm. [8] In any of the above [1] to [7], the light-emitting component is a compound having a naphthalene structure, an anthracene structure, a pyrene structure, a perylene structure, a tetracene structure, a BODIPY structure, a diketopyrrolopyrrole structure, an oxazole structure, or an oligophenylene structure. [9] In any one of [1] to [8] above, the photon upconversion material further contains a binder resin and water, forms an oil-in-water emulsion or a water-in-oil emulsion, and has film-forming ability.

[10] In [9] above, the photon upconversion material contains 1 to 150 parts by weight of the binder resin per 1 part by weight of the compound contained in the dispersion medium.

[11] In the above [9] or

[10] , the binder resin includes a polyvinyl alcohol-based resin, a polyurethane-based resin, a polystyrene-based resin, a polycarbonate-based resin, or a poly(meth)acrylate-based resin.

[12] In the above

[11] , the binder resin is a polyvinyl alcohol-based resin.

[13] According to another aspect of the present invention, there is provided a photon upconversion film. The photon upconversion film is formed from the photon upconversion material of any one of the above [9] to

[12] . The photon upconversion film includes a matrix composed of the binder resin, and the sensitizing component, the light-emitting component, and a phosphorus-based compound, sulfur-based compound, selenium-based compound, arsenic-based compound, or tellurium-based compound derived from the dispersion medium, dispersed in the matrix.

[0006] According to an embodiment of the present invention, it is possible to realize a photon upconversion material in which deterioration of performance over time is suppressed.

[0007] FIG. 1 is a conceptual diagram of energy levels illustrating the mechanism of photon upconversion.

[0008] Representative embodiments of the present invention will be described below, but the present invention is not limited to these embodiments.

[0009] A. Mechanism of Photon Up-Conversion The mechanism of photon up-conversion (hereinafter sometimes simply referred to as "up-conversion") will be described with reference to Figure 1. First, a donor absorbs incident light and converts it to an excited singlet state S Ｄ Intersystem crossing from Ｄ Then, triplet-triplet energy transfer (TTET) occurs from the donor to the acceptor, resulting in the excited triplet state T Ａ is generated. Then, the triple excited state T Ａ The triplet-triplet annihilation (TTA) occurs when the acceptors in the high excited singlet energy state S Ａ is generated. This high excited singlet energy state SＡ Upconversion light (light with more energy than the pump light) is emitted from the

[0010] B. Photon Upconversion Material B-1. Overview of Photon Upconversion Material A photon upconversion material according to an embodiment of the present invention includes a sensitizing component (donor) capable of absorbing light in a first wavelength region λ1, a light-emitting component (acceptor) capable of emitting light in a second wavelength region λ2 that has a shorter wavelength than the first wavelength region λ1, and a dispersion medium. In the photon upconversion material of this embodiment, the sensitizing component and the light-emitting component are dispersed or dissolved in the dispersion medium. The dispersion medium may be a liquid or a solid. Therefore, in this specification, the term "dispersion medium" refers to a liquid or solid in which the sensitizing component and the light-emitting component can be dispersed or dissolved.

[0011] In an embodiment of the present invention, the dispersion medium contains a phosphorus-based compound, a sulfur-based compound, a selenium-based compound, an arsenic-based compound, or a tellurium-based compound (these compounds may be referred to as "specific compounds"). Furthermore, in an embodiment of the present invention, the photon up-conversion material contains 1.0×10 sensitizing components per 100 parts by weight of the specific compounds. －５ parts by weight to 10.0 parts by weight, and 1.0×10 －４ parts by weight to 50.0 parts by weight inclusive.

[0012] In one embodiment, the photon upconversion material may further include a binder resin and water. In this embodiment, the photon upconversion material may typically form an oil-in-water emulsion or a water-in-oil emulsion. Furthermore, since the photon upconversion material includes a binder resin, it may have film-forming ability. Therefore, a photon upconversion film may be obtained from such a photon upconversion material. The obtained photon upconversion film may typically include a matrix composed of a binder resin, and a sensitizing component, a light-emitting component, and a specific compound dispersed in the matrix.

[0013] Each component contained in the photon upconversion material will be described below.

[0014] B-2. Sensitizing Component and Light-Emitting Component B-2-1. Sensitizing Component As is clear from the mechanism described in Section A, the sensitizing component absorbs light (incident light), transitions from an excited singlet state to an excited triplet state through intersystem crossing, and induces triplet-triplet energy transfer in the light-emitting component. Sensitizing components typically have a maximum absorption wavelength of 400 nm to 1200 nm. Examples of sensitizing components include compounds having a porphyrin structure, a phthalocyanine structure, a BODIPY (borondipyrromethene) structure, a coumarin structure, a quinone structure, a xanthene structure, a fullerene structure, a phenoxazine structure, a phenothiazine structure, an acridone structure, a carbazole structure, or a phenazaborine structure. Such compounds may contain metal atoms 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. Specific examples of compounds that can function as a sensitizing component will be described later in Section B-2-3.

[0015] The sensitizing component may be a quantum dot. The quantum dot may be made of any suitable material. The quantum dot may be made of preferably an inorganic material, more preferably an inorganic conductive material or an inorganic semiconducting material. Semiconductor materials include, for example, semiconductors of Groups II-VI, III-V, IV-VI, and IV. 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, Z nO, ZnS, ZnSe, ZnTe, CdS, CdSe, CdSeZn, CdTe, HgS, HgSe, HgTe, BeS, BeSe, BeTe, MgS, MgSe, GeS, GeSe, GeTe, SnS, SnSe, SnTe, PbO, PbS, PbSe, PbTe, CuF, CuCl, CuBr, CuI, Si３ N ４ , Ge ３ N ４ , Al ２ O ３ , (Al, Ga, In) ２ (S, Se, Te) ３ , Al ２ CO, and combinations (complexes) thereof.

[0016] The sensitizing component was 1.0×10 as described above relative to 100 parts by weight of the specific compound contained in the dispersion medium. －５ parts by weight to 10.0 parts by weight, preferably 1.0 x 10 －４ parts by weight to 5.0 parts by weight, more preferably 1.0 x 10 －３ parts by weight to 3.0 parts by weight, more preferably 2.0×10 －３ The photon upconversion material may contain the sensitizer component in an amount of 1.0 to 1.0 parts by weight. If the content of the sensitizer component is too small, sufficient triplet excitons may not be generated, resulting in insufficient efficiency in triplet-triplet annihilation. If the content of the sensitizer component is too large, the efficiency may be insufficient due to triplet-triplet annihilation between sensitizer component molecules or reabsorption of upconversion luminescence energy.

[0017] B-2-2. Light-Emitting Component As is clear from the mechanism described in Section A, the light-emitting component receives triplet-triplet energy transfer from the sensitizing component to generate an excited triplet state, and the light-emitting component molecules in the excited triplet state diffuse, collide, or come into proximity within a range where energy transfer is possible, causing triplet-triplet annihilation to generate an excited singlet of a higher energy level. The light-emitting component typically has an absorption maximum wavelength of 300 nm to 1100 nm. Various compounds having fused aromatic rings are known as light-emitting components. Specific examples include compounds having a naphthalene structure, an anthracene structure, a pyrene structure, a perylene structure, a tetracene structure, a BODIPY structure, a diketopyrrolopyrrole structure, an oxazole structure, or an oligophenylene structure. Specific examples of compounds that can function as light-emitting components will be described later in Section B-2-3.

[0018] The light-emitting component was 1.0 × 10 as described above with respect to 100 parts by weight of the specific compound contained in the dispersion medium. －４ parts by weight to 50.0 parts by weight, preferably 1.0 x 10 －３ parts by weight to 30.0 parts by weight, more preferably 2.0 × 10 －２ parts by weight to 20.0 parts by weight, more preferably 2.7×10 －２ parts by weight to 15.0 parts by weight, particularly preferably 5.0 x 10 －２ The photon upconversion material may contain the luminescent component in an amount of 1 to 10.0 parts by weight. If the content of the luminescent component is too small, the distance between the luminescent component molecules may become too large, and triplet excitons received from the sensitizing dye may not be able to diffuse between the luminescent component molecules. If the content of the luminescent component is too large, concentration quenching may occur, leading to inactivation.

[0019] 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, even more preferably 1:30 to 1:200, and particularly preferably 1:35 to 1:100. When the blending ratio is within this range, triplet excitons generated from the sensitizing component are efficiently transferred to the luminescent dye, deactivation between the luminescent dyes is minimized, and triplet-triplet annihilation can be satisfactorily achieved.

[0020] B-2-3. Combinations of Sensitizing Components and Light-Emitting Components Representative combinations of sensitizing components and light-emitting components according to the wavelengths of incident light and upconversion light are as follows: Note that these combinations are merely examples, and embodiments of the present invention are not limited to these combinations.

[0021] The sensitizing component that absorbs light in the wavelength region λ1 of 510 nm to 550 nm is the following compound, and the light-emitting component that emits (emits) light in the wavelength region λ2 of 400 nm to 500 nm is the following compound. This combination can upconvert green light to blue light. <Sensitizing Component> <Luminescent components>

[0022] The sensitizing component that absorbs light in the wavelength region λ1 of 610 nm to 650 nm is the following compound, and the light-emitting component that emits (emits) light in the wavelength region λ2 of 500 nm to 600 nm is the following compound. This combination can upconvert red light to yellow-green light. <Sensitizing Component> <Luminescent components>

[0023] The sensitizing component that absorbs light in the wavelength region λ1 of 700 nm to 810 nm is the following compound, and the light-emitting component that emits (emits) light in the wavelength region λ2 of 500 nm to 700 nm is the following compound. This combination can upconvert near-infrared light to visible light (red light to green light). <Sensitizing Component> <Luminescent components>

[0024] The sensitizing component that absorbs light in the wavelength region λ1 of 700 nm to 730 nm is the following compound, and the light-emitting component that emits (emits) light in the wavelength region λ2 of 400 nm to 500 nm is the following compound. This combination can upconvert near-infrared light to visible light (blue light). <Sensitizing Component> <Luminescent components>

[0025] The sensitizing component that absorbs light in the wavelength region λ1 of 410 nm to 500 nm is the following compound, and the light-emitting component that emits (emits) light in the wavelength region λ2 of 300 nm to 400 nm is the following compound. This combination can upconvert blue light to ultraviolet light. <Sensitizing Component> <Luminescent components>

[0026] The sensitizing component that absorbs light in the wavelength region λ1 of around 630 nm to 640 nm (e.g., 635 nm) is quantum dots (CdSe, CdSe / ZnS), and the light-emitting component that emits (emits) light in the wavelength region λ2 of around 440 nm to 460 nm (e.g., 450 nm) is the following compound. This combination can upconvert near-infrared light to visible light (blue light). <Light-emitting component>

[0027] The sensitizing component that absorbs light in the wavelength region λ1 of around 970 nm to 990 nm (for example, 980 nm) is quantum dots (PbSe, PbS / CdS), and the light-emitting component that emits (emits) light in the wavelength region λ2 of around 550 nm to 570 nm (for example, 560 nm) is the following compound. This combination can upconvert near-infrared light to visible light (green light). <Light-emitting component>

[0028] B-2-4. Dispersion Medium As described above, the dispersion medium contains a phosphorus-based compound, a sulfur-based compound, a selenium-based compound, an arsenic-based compound, or a tellurium-based compound (specific compound). The specific compounds may be used alone or in combination of two or more. These specific compounds typically have an antioxidant function. By using a dispersion medium containing such a specific compound, a photon upconversion material can be realized in which performance degradation over time is suppressed. More specifically, by using such a specific compound as a dispersion medium, a very large amount of the specific compound can be introduced into the photon upconversion material. Specifically, the content of the specific compound in the photon upconversion material can be significantly greater than the content of the sensitizing component and the luminescent component. As described above, the specific compound typically has an antioxidant function, and such a large amount of the specific compound can significantly suppress oxidation of the sensitizing component and the luminescent component. As a result, performance degradation over time of the photon upconversion material can be significantly suppressed. While various factors contribute to such performance degradation over time, using a large amount of the specific compound can particularly suppress performance degradation due to light. That is, according to an embodiment of the present invention, a photon upconversion material with excellent light resistance can be realized. Furthermore, by using a large amount of the specific compound compared to the sensitizing component and the light-emitting component, when a photon upconversion film is formed from the photon upconversion material, a predetermined amount or more of the specific compound can remain in the resulting film. As a result, the photon upconversion film can also have excellent light resistance. Note that the above mechanism is merely speculation and does not restrict the present invention or interpret the present invention in a limiting manner.

[0029] Examples of phosphorus compounds include triphenylphosphine, methyldiphenylphosphine, ethoxydiphenylphosphine, methoxydiphenylphosphine, ethyldiphenylphosphine, dimethyl phenylphosphonite, diphenylpropylphosphine, phenyl diphenylphosphine, tributylphosphine, triphenyl phosphite, diethyl phenylphosphonite, isopropyldiphenylphosphine, dimethylphenylphosphine, diethylphenylphosphine, triisopropyl phosphite, trimethylphosphine, triethylphosphine, triethyl phosphine, diphenylphosphine, triisopropylphosphine, phenylphosphine, trimethyl phosphite, diisopropylphosphine, methyldiphenyl phosphite, tripropylphosphine, diethyl methylphosphonite, triisobutylphosphine, bis(1-methylethyl)phosphine, diisobutylphosphine, tri(phenyl-2,3,4,5,6,-d5)phosphine, diisopropyl phenylphosphonite, bis(1-methylethyl)phenylphosphine, (2-methylpropyl)phosphine, Diethyl ethyl phosphonite, diphenyl phenyl phosphonite, dimethyl methyl phosphonite, phenyl dipropyl phosphine, tripropyl phosphite, dimethyl ethyl phosphonite, butyl diphenyl phosphine, dimethyl 1-methylethyl phosphite, dibutyl phenyl phosphine, dibutyl phosphine, tri(methyl-d3)phosphine, methyl phenyl phosphine, 1-methylethyl diphenyl phosphonite, (2-methylpropyl)diphenyl phosphine, methyl dipropyl phosphine, dimethyl propyl phosphine, methyl bis(1-methylethyl)phosphine, (1-methylpropyl)diphenyl phosphine, ethyl bis(1-methylethyl)phosphine, bis(1-methylethyl)phenyl phosphine, diethyl phenyl phosphite, methyl-P-methyl-P-phenyl phosphonite, (2-methylpropyl)phenyl phosphine, (1-methylethyl)phenyl phosphine, diethyl 1-methylethyl phosphite, bis(1-methylethyl)P-methyl phosphonite, methyl dipropyl phosphite, methyl(1-methylethyl)phenyl phosphine, propyl P,P-dipropyl phosphonite, ethyl bis(1-methylethyl) phosphite, phenylpropyl phosphine, ethyl P,P-dibutyl phosphonite, butylmethylphenylphosphine, diethylmethyl phosphite, butylphenylphosphine, butyldiethylphosphine, dibutylethylphosphine, butylmethylphosphine, phenyldipropyl phosphite, diphenylisopropyl phosphite, methyl(2-methylpropyl)phenylphosphine, methylbis(1-methylethyl) phosphite, ethylphenylphosphine, methylphenylpropylphosphine, (1-methylpropyl)phenylphosphine, ethyl P,P-diethyl phosphonite, bis(1-methylethyl) P-ethyl phosphonite, dipropyl P-propyl phosphonite, ethylphenylpropylphosphine, butylphenylpropylphosphine, diethylmethylphosphine, dipropylphosphine, dibutyl(1-methylpropyl)phosphine, tris(1-methylpropyl ) phosphine, phenylphosphine-d, bis(1-methylethyl)phosphonite, 1-methylethyl P-ethyl-P-phenylphosphonite, dipropyl P-phenylphosphonite, ethyl methylphenylphosphine, ethyl methylphenylphosphine, 1-methylethyl P,P-dibutylphosphonite, methyl(1-methylethyl)phenylphosphine, diphenyl P-(1-methylethyl)phosphonite, monoethyl phosphite, methylphenylpropylphosphine, bis(1-methylethyl)propyl phosphite, dipropyl phosphonite, ethyl ethyl methylphosphonite, diethyl P-(1-methylethyl)phosphonite, butylethylphenylphosphine, bis(1-methylpropyl)phenylphosphine, butyldimethylphosphine, dimethyl(1-methylpropyl)phosphine, tri(ethyl-d5)phosphine, tri(phenyl-2,6-d2)phosphine, tri(phenyl-2-d)phosphine, tri(phenyl-3,5-d2) Phosphine, triphenyl phosphite, trisnonylphenyl phosphite, tricresyl phosphite, triethyl phosphite, triethyl phosphite, tris(2-ethylhexyl) phosphite, tridecyl phosphite, trilauryl phosphite, tris(tridecyl) phosphite, trioleyl phosphite, diphenyl mono(2-ethylhexyl) phosphite, diphenyl monodecyl phosphite, diphenyl mono(tridecyl) phosphite, trilauryl trithiophosphine Examples of the phosphate include bis(2-ethylhexyl)hydrogen phosphite, diethyl hydrogen phosphite, bis(2-ethylhexyl)hydrogen phosphite, dilauryl hydrogen phosphite, diphenyl hydrogen phosphite, tetraphenyldipropylene glycol diphosphite, bis(decyl)pentaerythritol diphosphite, bis(tridecyl)pentaerythritol diphosphite, tristearyl phosphite, distearyl pentaerythritol diphosphite, and tris(2,4-di-t-butylphenyl)phosphite.

[0030] Examples of sulfur compounds include thioanisole, thiophenol, tert-butylmethyl sulfide, tert-butyl mercaptan, tert-butyl sulfide, [(1-methylethyl)thio]benzene, 3-methyl-1-butanethiol, 2-methyl-1-butanethiol, (propylthio)benzene, benzenesulfenyl chloride, 4-methyl-1-pentanethiol, 2-ethyl-1-butanethiol, [(1-methylpropyl)thio]benzene, 2-methyl-2-pentanethiol, 2-methyl-2-butanethiol, 2-(ethylthio)-2-methylpropane, 3,3-dimethyl-1-butanethiol, 3-methyl-1-butanethiolethyl-3-pentanethiol, 2-methyl-1-pentanethiol, isobutylphenyl sulfide, 2-methyl-3-pentanethiol, 4-methyl-2-pentanethiol, 3-methyl-2-pentanethiol, 3-[(1,1-dimethylethyl)thio]-1-propene, 2,4,4,-trimethyl-1-pentanethiol, 2- Methyl-2-hexanethiol, 2-methyl-2-[(1-methylethyl)thio]propane, 2,2-dimethyl-1-butanethiol, 2-methyl-2-undecanethiol, 3-methyl-1-pentanethiol, [(1,1-dimethylethyl)thio]benzene, 1-[(1,1-dimethylethyl)thio]butane, 2,3-dimethyl-1-butanethiol, 4,4-dimethyl-2-pentanethiol, 2,3,3-trimethyl-1-butanethiol, 2,2,3-trimethyl-1-butanethiol, 2,2-diethyl-1-butanethiol, 3-ethyl-1-pentanethiol, 5,5-dimethyl-2-hexanethiol, 2,4,4-trimethyl-2-pentanethiol, 4,4-dimethyl-1-pentanethiol, 2-methyl-2-octanethiol, 2-methyl-2-(propylthio)propane, 2-methyl-2-(methylthio)butane, [(3-methylbutyl)thio]benzene, 2,2-dimethyl-1-(methylthio)propane, 3-methyl-3-(methylthio)-1-butyne, 2,4,6-trimethyl-4-nonanethiol, 2-methyl-3-(methylthio)butane, [(2-methyl-3-buten-1-yl)thio]benzene, 3-methyl-3-pentanethiol, 3-methyl-3-hexanethiol, 2-methyl-2-heptanethiol, [(2,2-dimethylpropyl)thio]benzene, 2-(ethylthio)-2-methylbutane, 3-methyl-3-undecanethiol, 2-(ethylthio)-2-methylbutane[(1,1-dimethylethyl)thio]pyrimidine, 3-[(1,1-dimethylethyl)thio]-1-propyne, 2-[(1,1-dimethylethyl)thio]naphthalene, 2-methyl-2-pentadecanethiol, 2-[(1,1-dimethylethyl)thio]pyridine, 1-[(1,1-dimethylethyl)thio]hexane, (methyl-13C-thio)benzene, 5,5-dimethyl-1-hexanethiol, 4,8,8-trimethyl-4-nonanethiol, 2,2,4-trimethyl-1-pentanethiol, 3-ethyl-3-hexanethiol, [(3,3-dimethylbutyl)thio]benzene, 3-[(1,1-dimethylethyl)thio]pyridazine, [(2-ethyl 2-(ethynylthio)-2-methylpropane, 2-methyl-2-tridecanethiol, 3,3-dimethyl-2-butanethiol, 5-methyl-1-hexanethiol, 4-methyl-1-hexanethiol, 3-methyl-1-hexanethiol, 4,4-dimethyl-1-hexanethiol, 1-[(1,1-dimethylethyl)thio]naphthalene, [(2,2-dimethyl-1-methylenepropyl)thio]benzene, 2,2,3 , 3-tetramethyl-1-butanethiol, 2,3-dimethyl-3-pentanethiol, [(1,1-dimethyl-2-propen-1-yl)thio]benzene, [(1,1,5-trimethylhexyl)thio]benzene, 2-methyl-2-nonanethiol, 2-[(1,1,2-trimethylpropyl)thio]pyridine, [[2-methyl-1-(1-methylethyl)propyl]thio]benzene, 2,2-dimethyl-1-pentanethiol, [(2-methyl-3-butyn-1-yl)thio]benzene, and 2-methyl-1-hexanethiol.

[0031] Examples of selenium compounds include phenylselenol, diphenyldiselenide, dimethyldiselenide, diethyldiselenide, (methylseleno)benzene, (propylseleno)benzene, 2-(methylseleno)pyridine, 2,2'-selenobis[propane]3,3'-selenobis[1-propene], and 1-(propylseleno)propane.

[0032] Examples of arsenic compounds include triphenylarsine, triethylarsine, trimethylarsine, dimethylphenylarsine, trimethyl arsenite, triphenyl arsenite, and triethynylarsine.

[0033] Examples of tellurium compounds include 1,1'tellurobis[butane], dimethyl tellurium, 1,1'-tellurobis[benzene], 2,2'tellurobis[furan], 1,1'tellurobis[propane], and (methyltelluro)benzene.

[0034] Among the specific compounds, phosphorus-based compounds or sulfur-based compounds can be preferably used. Phosphorus-based compounds or sulfur-based compounds have the advantage of easily reacting with oxygen. Preferred phosphorus-based compounds include, for example, tris(2-ethylhexyl)phosphite, triphenylphosphine, triphenylphosphine, methyldiphenylphosphine, methoxydiphenylphosphine, dimethyl phenylphosphonite, phenoxydiphenylphosphine, and tributylphosphine. Preferred sulfur-based compounds include, for example, 4,6-bis(octylthiomethyl)-o-cresol, ditridecyl 3,3'-thiobispropionate, diphenyl sulfide, dibutyl sulfide, diphenyl disulfide, and butyl disulfide.

[0035] In addition to the specific compound, the dispersion medium may contain any appropriate liquid compound, such as toluene, 4'-phenyl-4-cyanobiphenyl (5CB), tetrahydrofuran (THF), dichloromethane, chloroform, ethyl acetate, dimethyl sulfoxide, phenylcyclohexane, hexylbenzene, and 4-phenyl-1-cyclohexane.

[0036] The content of the specific compound in the dispersion medium is preferably 5% by weight or more, more preferably 10% by weight or more, even more preferably 20% by weight or more, particularly preferably 50% by weight or more, and particularly preferably 65% ​​by weight or more. The content of the specific compound in the dispersion medium may be, for example, 100% by weight. That is, the dispersion medium may be composed only of the specific compound.

[0037] B-2-5. Binder Resin The binder resin can be appropriately selected depending on the configuration of the photon upconversion material, the type of emulsion to be formed (oil-in-water type or water-in-oil type), and the desired configuration and properties of the resulting photon upconversion film. Specifically, the binder resin may be a water-soluble resin or an oil-soluble resin.

[0038] Specific examples of water-soluble resins include polystyrene sulfonate, polyethylene oxide, polyethyleneimine, polyvinyl alcohol resins, cellulose resins, and polyurethane resins. Examples of polystyrene sulfonate include sodium polystyrene sulfonate. Examples of polyethyleneimine include polyethyleneimine hydrochloride. Examples of polyvinyl alcohol resins include polyvinyl alcohol, amine-modified polyvinyl alcohol, and carboxylic acid-modified polyvinyl alcohol. Examples of cellulose resins include hydroxyethyl cellulose.

[0039] Specific examples of oil-soluble resins include (meth)acrylic resins, polystyrene resins, polycarbonate resins, polyester resins, and polyurethane resins. Examples of (meth)acrylic resins include polymethyl methacrylate (PMMA). Examples of polyester resins include polyethylene terephthalate (PET).

[0040] The Hansen solubility parameter (HSP) distance Ra between the binder resin and the sensitizing component and the luminescent component is, for example, 10 (MPa) １／２ or more, for example, 11 (MPa)１／２ or more, preferably 12 (MPa) １／２ More preferably, 15 (MPa) １／２ More preferably, 18 (MPa) １／２ On the other hand, the HSP distance Ra between the binder resin and the sensitizing component and between the binder resin and the luminescent component is, for example, 25 (MPa) １／２ is less than or equal to 23 (MPa) １／２ More preferably, 21 (MPa) or less. １／２ The HSP distance Ra is in this range, which means that the affinity between the binder resin and the sensitizing component and the luminescent component is low. As a result, the migration of the sensitizing component and the luminescent component into the binder resin is significantly suppressed, and in the resulting photon upconversion film (porous film), the sensitizing component and the luminescent component can be present at the interface between the matrix (binder resin) and the voids. Details of the HSP distance Ra are described, for example, in International Publication No. 2023 / 074040. The description of this publication is incorporated herein by reference.

[0041] The binder resin is preferably a polyvinyl alcohol resin, because it has an excellent balance of oxygen permeability, availability, ease of handling, ease of film formation, and the like.

[0042] The photon up-conversion material preferably contains 150 parts by weight or less of binder resin per 1 part by weight of the specific compound, more preferably 50 parts by weight or less, even more preferably 30 parts by weight or less, particularly preferably 20 parts by weight or less, and especially preferably 10 parts by weight or less. The lower limit of the binder resin content may be, for example, 1 part by weight or more, or, for example, 2 parts by weight or more, or, for example, 3 parts by weight or more. When the binder resin content in the photon up-conversion material is within this range, the sensitizing component and the light-emitting component can be encapsulated in the binder resin, and the light-emitting intensity can be increased.

[0043] B-2-6. Water The water content in the photon up-conversion material can be appropriately set depending on the type of binder resin (water-soluble or oil-soluble), the type of emulsion that can be formed depending on the type of binder resin (oil-in-water type or water-in-oil type), the structure and properties desired for the resulting photon up-conversion film, etc.

[0044] C. Photon Upconversion Film As described above, the photon upconversion material according to an embodiment of the present invention can form a photon upconversion film. Accordingly, such photon upconversion films can also be encompassed within the scope of the present invention. As described above, the photon upconversion film can include a matrix composed of a binder resin and a sensitizing component, a light-emitting component, and a specific compound dispersed in the matrix. For example, when a cross section of the photon upconversion film is observed with a scanning electron microscope (SEM), the film may have a structure that appears uniform in appearance, or a structure in which the dispersion medium appears to be phase-separated (a sea-island structure in which the dispersion medium is an island). When the film has an apparent phase-separated structure, the size of the dispersed phase (island portion) can be, for example, several hundred nanometers to several tens of micrometers. The dispersed phase may contain the dispersion medium (essentially the sensitizing component, the light-emitting component, and / or the specific compound dispersed or dissolved in the dispersion medium), or it may be voids.

[0045] The thickness of the photon up-conversion film is preferably 5 μm to 200 μm, more preferably 10 μm to 150 μm, and even more preferably 15 μm to 100 μm. If the thickness of the photon up-conversion film is within this range, light with high emission intensity can be extracted. If the thickness is too large, light may not reach the inside of the film, and the amount of luminescent components involved in emission may decrease. As a result, the emission intensity of the extracted light may decrease. If the thickness is too small, the amount of sensitizing components may decrease, and as a result, the emission intensity of the extracted light may decrease.

[0046] D. Light Resistance As described above, the photon upconversion material according to the embodiment of the present invention exhibits reduced performance degradation over time, particularly reduced performance degradation due to light. That is, the photon upconversion material has excellent light resistance. This is true for both the photon upconversion material described in Section B and the photon upconversion film described in Section C.

[0047] The photon upconversion material (and consequently the photon upconversion film) maintains good upconversion efficiency, transmittance, and absorbance, even after, for example, accelerated light resistance testing using xenon. Specifically, when the luminous efficiency before the accelerated test is φ1 and the luminous efficiency after the accelerated test is φ2, φ2 / φ1 is preferably 0.21 or greater, more preferably 0.40 or greater, and even more preferably 0.50 or greater. φ2 / φ1 can ideally be 1.0. Similarly, when the transmittance before the accelerated test is T1 and the transmittance after the accelerated test is T2, T2 / T1 is preferably 2.4 or less, more preferably 1.8 or less, and even more preferably 1.5 or less. T2 / T1 can also ideally be 1.0. Furthermore, when the absorbance before the accelerated test is A1 and the absorbance after the accelerated test is A2, (A1-A2) is preferably 0.6 or less, more preferably 0.3 or less, and even more preferably 0.15 or less. Ideally, (A1-A2) can be 0.0. The accelerated light resistance test using xenon can be performed under the following conditions, for example: Xenon lamp illuminance: 120 W / m ２ (300nm to 400nm) Testing environment: 30°C, 55% RH Testing time: 1 hour

[0048] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. Measurement and evaluation methods in the examples are as follows. Unless otherwise specified, "parts" and "%" in the examples are by weight.

[0049] (1) Upconversion (UC) Efficiency (1-1) Photon Upconversion Material 3 mL of the photon upconversion solution obtained in the Examples and Comparative Examples was placed in a standard quartz cell for a spectrophotometer (fully transparent, optical path length 10 mm, optical path width 10 mm, size 12.7 mm × 12.7 mm × 45 mm), and left to stand for 1 hour under a white fluorescent light of 380 lx in the atmosphere. After that, the luminous efficiency φ1 before the test and the luminous efficiency φ2 after the test were measured using an absolute quantum yield measurement system (manufactured by Hamamatsu Photonics K.K., product name "Quantaurus-QY Plus C11347-02", detection wavelength: 300 nm to 1100 nm). For absolute quantum yield measurements, a diode laser (808 nm, 200 mW, 532 nm, 75 mW, 460 nm, 500 mW, RGB Photonics) was used as an excitation source, with the light intensity adjusted using the laser output and an ND filter. The 808 nm wavelength was 27,000 mW / cm. ２ , 532 nm is 31,000 mW / cm ２ , 460 nm is 31000 mW / cm ２ The light intensity was adjusted so that the sample was irradiated with light at a ratio of φ2 / φ1. The ratio φ2 / φ1 was calculated and evaluated according to the following criteria: A (Good): φ2 / φ1 is 0.5 or more B (Acceptable): φ2 / φ1 is 0.2 or more and less than 0.5 C (Unacceptable): φ2 / φ1 is less than 0.2

[0050] (1-2) Photon Up-Conversion Film The photon up-conversion films obtained in the examples and comparative examples were measured for luminous efficiency φ1 before testing using an absolute quantum yield measurement system (manufactured by Hamamatsu Photonics, product name "Quantaurus-QY Plus C11347-02", detection wavelength: 300 nm to 1100 nm). The measurement conditions were the same as those in (1-1) above. Next, the photon up-conversion films were subjected to an accelerated light resistance test using xenon. The specific conditions for the accelerated test were as follows: Testing machine: Xenon weather meter testing machine (manufactured by Suga Test Instruments Co., Ltd., product name "SX75") Xenon lamp illuminance: 120 W / m ２(300 nm to 400 nm) Environment inside the tester: 30°C, 55% RH Test time: 1 hour After the test, the luminous efficiency φ2 of the film was measured in the same manner as above. Finally, φ2 / φ1 was calculated and evaluated according to the following criteria: A (Good): φ2 / φ1 is 0.5 or more B (Acceptable): φ2 / φ1 is 0.2 or more and less than 0.5 C (Unacceptable): φ2 / φ1 is less than 0.2

[0051] (2) Transmittance and Absorbance (2-1) Photon Up-Conversion Material 3 mL of the photon up-conversion solution obtained in the Examples and Comparative Examples was placed in a standard quartz cell for spectrophotometers (fully transparent, optical path length 10 mm, optical path width 10 mm, size 12.7 mm x 12.7 mm x 45 mm) and left to stand for 1 hour under atmospheric pressure and a white fluorescent lamp at 380 lx. After this, the transmittance T1 before the test and the transmittance T2 after the test were measured using an ultraviolet-visible-near-infrared spectrophotometer (manufactured by JASCO Corporation, product name "V-750"). The measurement was performed in the wavelength range of 200 nm to 900 nm, and the transmittance at the wavelength of the longest wavelength among the peaks showing the minimum transmittance of the sensitizing component was used as the transmittance in this evaluation. Furthermore, the absorbances A1 and A2 were calculated from the measured transmittances T1 and T2 using the following formula. T2 / T1 and (A1-A2) were calculated and evaluated according to the following criteria. A = log10(1 / T) <Transmittance> A (Good): T2 / T1 is less than 1.5 B (Acceptable): T2 / T1 is 1.5 or more and less than 2.4 C (Fail): T2 / T1 is 2.4 or more <Absorbance> A (Good): (A1 - A2) is less than 0.15 B (Acceptable): (A1 - A2) is 0.15 or more and less than 0.30 C (Failable): (A1 - A2) is 0.30 or more

[0052] (2-2) Photon Up-Conversion Film The transmittance T1 before testing of the photon up-conversion films obtained in the Examples and Comparative Examples was measured using an ultraviolet-visible-near-infrared spectrophotometer (Hitachi High-Tech Corporation, product name "UH4150"). The measurement was performed in the wavelength range of 200 nm to 1200 nm, and the transmittance was determined in the same manner as in (2-1) above. The photon up-conversion films were then subjected to an accelerated light resistance test using xenon. The accelerated test conditions were the same as in (1-2) above. The transmittance T2 of the films after the test was measured in the same manner as above. The absorbances A1 and A2 were calculated from T1 and T2 in the same manner as above. Finally, T2 / T1 and (A1-A2) were calculated and evaluated according to the following criteria. <Transmittance> A (Good): T2 / T1 is less than 1.5 B (Acceptable): T2 / T1 is 1.5 or more and less than 2.4 C (Fail): T2 / T1 is 2.4 or more <Absorbance> A (Good): (A1 - A2) is less than 0.15 B (Acceptable): (A1 - A2) is 0.15 or more and less than 0.30 C (Failable): (A1 - A2) is 0.30 or more

[0053] Example 1 In a glove box, 4.7 × 10 meso-tetraphenyl-tetraanthraporphyrin palladium (PdTPTAP: chemical formula shown below) was used as a sensitizing component. －２ mg, and 5.8 × 10 rubrene (chemical formula below) as a luminescent component －１ The specific compound was dissolved in 2,000 mg of tris(2-ethylhexyl)phosphite and 866 mg of toluene to prepare a solution. －３ parts and the luminescent component rubrene at 2.9 × 10 －２ A solution was prepared by partially dissolving the PdTPTAP in the solution. The concentration of PdTPTAP in the solution was 0.01 mM, and the concentration of rubrene was 0.36 mM. That is, the molar ratio of sensitizing component to luminescent component was 1:36. The absorption wavelength of the obtained solution was 797 nm, and the emission wavelength was 540 nm. The obtained solution was subjected to the evaluations (1) and (2) above. The results are shown in Table 1. <Sensitizing component> <Luminescent components>

[0054] Comparative Example 1 A solution was prepared in the same manner as in Example 1, except that 2598 mg of toluene was used instead of 2000 mg of tris(2-ethylhexyl)phosphite and 866 mg of toluene, i.e., no specific compound was used as the dispersion medium. The obtained solution was subjected to the same evaluations as in Example 1. The results are shown in Table 1.

[0055] Example 2 1. Preparation of a solution of a sensitizing component and a luminescent component PdTPTAP 3.4 × 10 as a sensitizing component －１ 4.3 mg of rubrene as a light-emitting component was dissolved in 400 mg of triphenyl phosphite and 400 mg of tetrahydrofuran (THF) to prepare a solution. －２ A solution was prepared by dissolving 1.1 parts of sensitizing component and 1.1 parts of luminescent component rubrene. The PdTPTAP concentration in the solution was 0.277 mM, and the rubrene concentration was 10 mM. That is, the molar ratio of sensitizing component to luminescent component was 1:36.

[0056] 2. Preparation of Emulsion 0.8 ml of the solution obtained above was added to 5 g of an aqueous polyvinyl alcohol (PVA) solution (9% by mass). The solution was poured into a tube with an inner diameter of 0.75 mm and stirred (17,500 rpm) with a homogenizer until the entire mixture was emulsified. Using a mixer (THINKY), the mixture was stirred for 5 minutes in mixing mode (2,000 rpm) and for 5 minutes in degassing mode (2,200 rpm). In this way, an emulsion was prepared. The PVA used had a degree of polymerization of 1,700 and a degree of saponification of 99%.

[0057] 3. Preparation of Photon Up-Conversion Film The emulsion obtained above was applied to a polyimide film (substrate) using an applicator to a coating thickness of 700 μm. The coating / polyimide film laminate was dried in a thermostatic chamber. The drying temperature was 80°C, and the drying time was 30 minutes. After drying, the laminate was allowed to cool naturally to room temperature (23°C). Finally, the dried coating was peeled off from the polyimide film to obtain a photon up-conversion film (thickness 63 μm). Note that the steps after emulsion preparation were performed in air in a dark place (under an environment with only darkroom light). The absorption wavelength of the obtained film was 797 nm, and the emission wavelength was 540 nm. The obtained film was subjected to the evaluations (1) and (2) above. The results are shown in Table 1.

[0058] Comparative Example 2 A photon up-conversion film was produced in the same manner as in Example 2, except that 346 mg of 5CB and 400 mg of THF were used instead of 400 mg of triphenyl phosphite and 400 mg of THF, i.e., no specific compound was used as the dispersion medium. The resulting film was subjected to the same evaluations as in Example 2. The results are shown in Table 1.

[0059] Examples 3 to 12 Photon up-conversion films were produced in the same manner as in Example 2, except that the types of sensitizing component, luminescent component, and dispersion medium (specific compound), as well as the amounts used (blending ratios) thereof, were as shown in Table 1. The obtained films were subjected to the same evaluations as in Example 2. The results are shown in Table 1 together with the absorption wavelength and emission wavelength.

[0060]

[0061] The symbols for the sensitizing component, light-emitting component, and specific compounds in Table 1 mean the following: <Sensitizing component> A: meso-tetraphenyl-tetraanthraporphyrin palladium (PdTPTAP) B: platinum (II) 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrin (PtOEP: chemical formula below) C: 3,3'-carbonylbis(7-diethylaminocoumarin) (chemical formula below) <Light-emitting component> X: rubrene Y: 9,10-diphenylanthracene (chemical formula below) Z: 1,4-bis((triisopropylsilyl)ethynyl)naphthalene (chemical formula below) <Specific Compounds> I: Tris(2-ethylhexyl)phosphite II: Triphenylphosphite III: Ditridecyl 3,3'-thiobispropionate IV: 4,6-bis(octylthiomethyl)-o-cresol

[0062] The photon upconversion materials according to the embodiments of the present invention can be suitably used to prepare photon upconversion films, which can be suitably used in solar cells or photovoltaics, photocatalysis, bioimaging, optical instruments, and the like.

Claims

1. A photosensitive material comprising a sensitizing component capable of absorbing light in a first wavelength region λ1, a light-emitting component capable of emitting light in a second wavelength region λ2 having a wavelength shorter than the first wavelength region λ1, and a dispersion medium, wherein the dispersion medium contains a compound selected from a phosphorus-based compound, a sulfur-based compound, a selenium-based compound, an arsenic-based compound, or a tellurium-based compound, and the sensitizing component is added in an amount of 1.0 x 10 parts by weight per 100 parts by weight of the compound. －５ parts by weight to 10.0 parts by weight of the light-emitting component, and －４ parts by weight to 50.0 parts by weight of a photon upconversion material.

2. The photon upconversion material according to claim 1, wherein the dispersion medium has an antioxidant function.

3. The photon upconversion material according to claim 2, wherein the dispersion medium is a phosphorus-based compound or a sulfur-based compound.

4. The photon upconversion material of claim 3, wherein the dispersion medium is selected from tris(2-ethylhexyl)phosphite, triphenylphosphine, triphenylphosphine, methyldiphenylphosphine, methoxydiphenylphosphine, dimethyl phenylphosphonite, phenoxydiphenylphosphine, tributylphosphine, 4,6-bis(octylthiomethyl)-o-cresol, or ditridecyl 3,3'-thiobispropionate, diphenyl sulfide, dibutyl sulfide, diphenyl disulfide, or butyl disulfide.

5. The photon upconversion material of claim 1, wherein the sensitizing component has a maximum absorption wavelength in the range of 400 nm to 1200 nm.

6. The photon upconversion material of claim 5, wherein the sensitizing component is a compound having a porphyrin structure, a phthalocyanine structure, a BODIPY structure, a coumarin structure, a quinone structure, a xanthene structure, a fullerene structure, a phenoxazine structure, a phenothiazine structure, an acridone structure, a carbazole structure, or a phenazaborine structure.

7. The photon upconversion material of claim 5, wherein the luminescent component has a maximum emission wavelength in the range of 300 nm to 1100 nm.

8. The photon upconversion material of claim 7, wherein the light-emitting component is a compound having a naphthalene structure, an anthracene structure, a pyrene structure, a perylene structure, a tetracene structure, a BODIPY structure, a diketopyrrolopyrrole structure, an oxazole structure, or an oligophenylene structure.

9. The photon upconversion material according to any one of claims 1 to 8, further comprising a binder resin and water, forming an oil-in-water emulsion or a water-in-oil emulsion, and having film-forming properties.

10. The photon upconversion material according to claim 9, wherein the binder resin is contained in an amount of 1 to 150 parts by weight per 1 part by weight of the compound contained in the dispersion medium.

11. The photon upconversion material according to claim 10, wherein the binder resin comprises a polyvinyl alcohol-based resin, a polyurethane-based resin, a polystyrene-based resin, a polycarbonate-based resin, or a poly(meth)acrylate-based resin.

12. The photon upconversion material according to claim 11, wherein the binder resin is a polyvinyl alcohol-based resin.

13. A photon up-conversion film formed from the photon up-conversion material according to claim 9, comprising a matrix made of the binder resin, and the sensitizing component, the luminescent component, and a phosphorus-based compound, sulfur-based compound, selenium-based compound, arsenic-based compound, or tellurium-based compound derived from the dispersion medium dispersed in the matrix.

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