Photon upconversion porous body, method for producing same, light irradiation method, and flow path for light irradiation

Abstract

By using this photon upconversion porous body which has a skeleton part that includes a donor and an acceptor, and a through hole of, for example, 0.1 µm to 100 µm, UC light irradiation in a flow system becomes possible in various fields including a photochemical reaction in which UC light is used.

Description

Photon upconversion porous body, its manufacturing method, light irradiation method, and light irradiation flow path

[0001] The present invention relates to a photon upconversion porous body useful as a source of ultraviolet light, a method for producing the same, and a light irradiation method and a light irradiation flow path using the photon upconversion porous body.

[0002] Photon upconversion (UC) is a technology that converts low-energy light into high-energy light. It has attracted attention as an energy generation technology that can improve the efficiency of solar-powered devices, including solar cells, organic photoreactions, and artificial photosynthesis. A known material system driven by photon upconversion is a photon upconversion composition that combines a donor that functions as a triplet sensitizer and an acceptor that functions as an emitter. In this composition, when the donor is excited to an excited singlet state by irradiation with excitation light, it undergoes intersystem crossing to an excited triplet state, and the triplet energy is transferred to the acceptor. When the acceptor receives energy and reaches an excited triplet state, the triplets between the two molecules meet, causing triplet-triplet annihilation (TTA), and one of the molecules transitions to an excited singlet state with higher energy than the excited triplet state, resulting in light emission (photon upconversion luminescence). In this composition, irradiated light can be converted into light with higher energy (light with shorter wavelength) through such photon upconversion by triplet-triplet annihilation (TTA-UC). Development of such photon upconversion compositions that can achieve higher upconversion efficiency is underway, and among these, research on porous photon upconversion materials is also being conducted.

[0003] For example, Non-Patent Document 1 and Patent Document 1 propose a photon upconversion porous film in which an O / W emulsion of a toluene solution of Pd-tetraphenyltetraanthraporphyrin (sensitizing component) and rubrene (light-emitting component) with an aqueous polyvinyl alcohol solution is applied to a substrate, dried, and then peeled off to generate bubbles. In this porous film, the sensitizing component and light-emitting component are present at the interface between the polymer skeleton (matrix) and the voids, and upconversion light is generated by the upconversion mechanism of these components.

[0004] ACS Macro Lett. 2023, 12, 523-529

[0005] International Publication No. 2023 / 074040

[0006] As mentioned above, Non-Patent Document 1 and Patent Document 1 describe photon upconversion porous films. In these photon upconversion porous films, compressed emulsion particles in a dried coating undergo pseudo-foaming due to external forces applied during the peeling process, generating bubbles (voids). The voids are formed by either independent bubbles or the merging of multiple bubbles. Porous films with such bubbles have low fluid permeability, making them unsuitable for use in flow systems where a porous body is placed in a flow path to allow fluid to pass through, limiting their range of application. In light of this, the present inventors have conducted extensive research with the aim of providing a photon upconversion material that can be used in flow systems and has a wide range of applications.

[0007] As a result of intensive research to solve the above problems, the present inventors have found that by forming a photon upconversion material into a shape with through-holes, a photon upconversion porous body that can be used in a flow system and has a wide range of applications can be realized. The present invention has been proposed based on this finding and specifically has the following configuration.

[0008] [1] A photon upconversion porous body having a skeleton containing a donor and an acceptor and through-holes. [2] The photon upconversion porous body according to [1], wherein the through-hole diameter of the porous body is 0.1 to 100 μm. [3] The photon upconversion porous body according to [1] or [2], wherein the donor is dispersed in the acceptor. [4] The photon upconversion porous body according to [1] or [2], wherein the donor is present on the surface of the skeleton. [5] The photon upconversion porous body according to [1] or [2], wherein the skeleton further contains a matrix resin. [6] The photon upconversion porous body according to [5], wherein the acceptor is dispersed in the matrix resin. [7] The photon upconversion porous body according to [6], wherein the donor is further dispersed in the matrix resin. [8] The photon upconversion porous body according to any one of [1] to [7], wherein the skeleton is monolithic. [9] The photon upconversion porous body according to any one of [1] to [8], which absorbs visible light and emits ultraviolet light.

[10] The photon upconversion porous body according to [9], which emits ultraviolet light with a wavelength of 280 to 320 nm.

[11] A light irradiation method comprising irradiating the photon upconversion porous body according to any one of [1] to

[10] with light and irradiating a substance present in the through-holes with the photon upconversion light generated thereby.

[12] The light irradiation method according to

[11] , wherein the substance is supplied into the through-holes from outside the photon upconversion porous body.

[13] The light irradiation method according to

[11] or

[12] , wherein the photon upconversion porous body is irradiated with light while a fluid containing the substance is passed through the photon upconversion porous body.

[14] A flow path for light irradiation, in which the photon upconversion porous body according to any one of [1] to

[10] is installed in a flow path for a substance-containing fluid to flow.

[15] A method for producing a photon upconversion porous medium having a skeleton containing a donor and an acceptor and through-holes, the method comprising the steps of filling a porous mold having through-holes with a fluid containing the donor and the acceptor, solidifying the fluid, and then dissolving and removing the porous mold to form the skeleton.

[16] The production method according to

[15] , wherein the fluid further contains a monomer, and the solidification is carried out by polymerizing the monomer.

[17] A method for producing a photon upconversion porous medium having a skeleton containing a donor and an acceptor and through-holes, the method comprising the steps of filling a porous mold having through-holes with a fluid containing the acceptor, solidifying the fluid, then dissolving and removing the porous mold, and attaching the donor to the surface of the resulting porous medium to form the skeleton.

[18] A method for producing a photon upconversion porous material having a skeleton containing a donor and an acceptor and through-holes, the method comprising: preparing a solution in which the donor, the acceptor, a monomer, and a polymerization initiator are dissolved in two or more solvents; polymerizing the monomer to cause phase separation into a solid phase having the skeleton and a liquid phase; and removing the liquid phase.

[0009] The photon upconversion porous body of the present invention can also be applied to a flow system. Therefore, the photon upconversion porous body of the present invention enables UC light irradiation in a flow system in various fields that utilize UC light, such as photochemical reactions. The light irradiation method of the present invention allows a substance to be efficiently irradiated with UC light emitted from the photon upconversion porous body. The light irradiation flow path of the present invention allows a substance to be efficiently irradiated with UC light emitted from the photon upconversion porous body in a flow system.

[0010] FIG. 1 is a diagram illustrating the UC emission mechanism of the photon upconversion porous body of the present invention. FIG. 2 is an SEM photograph of a porous silica monolith produced in an example. FIG. 3 is a perspective view showing the manufacturing process of Example 1. FIG. 4 is an SEM photograph of UC porous body 1 produced in Example 1. FIG. 5 is a UC emission spectrum measured for UC porous body 1 at different excitation light intensities. FIG. 6 is a perspective view showing the manufacturing process of Example 2. FIG. 7 is an SEM photograph of the porous body of compound A2 produced in Example 2. FIG. 8 is an SEM photograph of UC porous body 2 produced in Example 2. FIG. 9 is a UC emission spectrum measured for UC porous body 2 at different excitation light intensities. FIG. 10 is a perspective view showing the manufacturing process of Example 3. FIG. 11 is an SEM photograph of the porous body produced in Example 3. FIG. 12 is a UC emission spectrum measured for UC porous body 3 at different excitation light intensities.

[0011] The present invention will be described in detail below. The following description of the constituent elements may be based on representative embodiments or specific examples, but the present invention is not limited to such embodiments. In this specification, a numerical range expressed using "to" means a range including the numerical values ​​before and after "to" as the lower and upper limits. In addition, the isotopes of hydrogen atoms present in the molecules of the compound used in the present invention are not particularly limited, and for example, when all hydrogen atoms in the molecule are １ H, or part or all of ２ H (deuterium D). In this specification, "visible light" means light having a wavelength in the range of more than 400 nm to 800 nm, and "ultraviolet light" means light having a wavelength in the range of 200 nm to 400 nm. In addition, in this specification, ultraviolet light having a wavelength of 280 to 320 nm is referred to as "UVB light," and light having a wavelength of 320 to 400 nm is referred to as "UVA light."

[0012] <Photon upconversion porous body> The photon upconversion porous body of the present invention has a skeleton containing a donor and an acceptor, and through-holes. The "photon upconversion porous body" of the present invention refers to a porous body that exhibits the ability to absorb light supplied to the porous body and emit light of a shorter wavelength. Thus, the "photon upconversion porous body" of the present invention exhibits the function of converting light supplied to the porous body into light of a shorter wavelength. The "porous body" in the "photon upconversion porous body" of the present invention refers to a solid having a skeleton (matrix) surrounding pores and through-holes. In this specification, the outer surface of the overall shape of the porous body is referred to as the "external surface," and the surface surrounding the through-holes in the skeleton and other pores (the internal surface of the porous body) is sometimes referred to as the "inner surface." In the photon upconversion porous body of the present invention, the source light converted into "shorter wavelength light" is light whose wavelength overlaps with the wavelength region (absorption wavelength region) in which the photon upconversion porous body exhibits optical absorption. Specifically, it is light whose wavelength overlaps with the wavelength region (absorption wavelength region) in which the donor described below exhibits optical absorption. This source light is preferably light in a wavelength region longer than the ultraviolet light region, and more preferably visible light. Furthermore, the "shorter wavelength light" to be converted is preferably ultraviolet light. The source light and the converted light may be light with a single maximum emission wavelength, or may be composite light containing multiple lights with different maximum emission wavelengths. In a preferred embodiment of the present invention, the photon upconversion porous body is a porous body that absorbs visible light and emits ultraviolet light. In a preferred embodiment of the present invention, the photon upconversion porous body is a porous body that absorbs visible light and emits UVB light. UVB light is light with a wavelength of 280 to 320 nm, for example, light with a wavelength of 280 to 315 nm. Here, UVB light is a type of light that does not pass through ordinary glass, so when a photon upconversion porous body that emits UVB light is placed in a glass container to form a UC light-emitting device, there is no need to take measures such as covering the glass with a shielding material to prevent the emitted UVB light from leaking to the outside.Therefore, photon upconversion porous bodies that emit UVB light are highly practical.

[0013] In this specification, the conversion of light absorbed by a photon upconversion porous body into light with a shorter wavelength and emission thereof is referred to as "photon upconversion luminescence" or "UC luminescence," the light emitted by photon upconversion luminescence (light with a shorter wavelength than the irradiated light) is referred to as "UC light," and the conversion efficiency of light irradiated onto a photon upconversion porous body into UC light is referred to as "upconversion efficiency" or "UC efficiency."

[0014] The "photon upconversion porous material" of the present invention contains at least a donor and an acceptor in the skeleton. Here, the "donor" absorbs light supplied to the composition, becomes excited, and provides the energy of the excited triplet state to the acceptor. The "acceptor" receives energy from the excited triplet state donor, causes photon upconversion by triplet-triplet annihilation (TTA-UC), and emits photon upconversion light (UC emission) by radiative deactivation from the excited singlet state thus generated. The mechanism of this UC emission will be explained with reference to FIG. 1. Here, the acceptor is an electron transport molecule having a lowest excited singlet energy level S １，Ａ is the lowest excited singlet energy level S of the donor １，Ｄ and its lowest excited triplet energy level T １，Ａ is the lowest excited triplet energy level T of the donor １，Ｄ In the present invention, the lowest excited triplet energy level T １，Ａ is the lowest excited triplet energy level T of the donor １，ＤIn FIG. 1, the light supplied to the composition is excitation light for the donor, that is, light whose wavelength overlaps with the absorption wavelength range of the donor. In FIG. 1, "ISC" indicates intersystem crossing, "TET" indicates triplet energy transfer from the donor to the acceptor, and "TTA" indicates triplet-triplet annihilation. First, when excitation light is irradiated onto a photon upconversion porous body containing a donor and an acceptor, the donor molecule (donor molecule) absorbs the light and transitions to an excited singlet state (S １，Ｄ ), then intersystem crossing occurs to form the excited triplet state (T １，Ｄ The energy of the donor molecule in the excited triplet state is transferred to the acceptor molecule (acceptor molecule). This results in a transition to the excited triplet state (T １，Ａ ), the triplet of the two molecules meets, triplet-triplet annihilation occurs, and one of the molecules enters the excited singlet state (S １，Ａ ) transition. In other words, photon upconversion occurs due to triplet-triplet annihilation of the acceptor molecule. The acceptor molecule thus reaches an excited singlet state, emitting fluorescence (UC light) and becoming inactivated, causing the composition to emit UC light. At this time, the excited singlet state (S １，Ａ ) has a very high energy level, and UC light with higher energy (shorter wavelength) than the excitation light can be obtained by radiative deactivation from its excited singlet state. Here, the fact that the light emitted from the porous body is photon upconversion light emission due to triplet-triplet annihilation means that the lifetime of photon upconversion light emission is between 10 and 150 ms. －１ The delayed fluorescence is on the order of milliseconds, and can be confirmed by the change in slope from 2 to 1 in a double logarithmic plot of the excitation light intensity dependence of photon upconversion luminescence intensity.

[0015] The skeleton and through-holes of the photon upconversion porous material of the present invention will be described in detail below. In the following description, unless otherwise specified, the terms "alkyl group," "alkoxy group," and "aryl group" refer to substituents within the ranges shown below. The "alkyl group" may be linear, branched, or cyclic. It preferably has 1 to 20 carbon atoms, more preferably 1 to 10, and even more preferably 1 to 6. Specific examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, and an isopropyl group, but the "alkyl group" is not limited to these specific examples. At least one hydrogen atom of the alkyl group may be substituted with a substituent. The "alkoxy group" may be linear or branched. It preferably has 1 to 20 carbon atoms, more preferably 1 to 10, and even more preferably 1 to 6. Specific examples of the alkoxy group include a methoxy group, an ethoxy group, an n-propoxy group, and an isopropoxy group, but the "alkoxy group" is not limited to these specific examples. At least one hydrogen atom of the alkoxy group may be substituted with a substituent. An "aryl group" may be composed of a monocyclic aromatic ring, a fused ring in which two or more aromatic rings are fused, or a linked ring in which two or more aromatic rings are linked. When two or more aromatic rings are linked, they may be linked in a linear or branched chain. The number of carbon atoms in the aromatic ring constituting the aryl group is preferably 6 to 22, more preferably 6 to 18, even more preferably 6 to 14, and even more preferably 6 to 10. Specific examples of the aryl group include a phenyl group, a naphthalenyl group, and a biphenyl group, but the "aryl group" is not limited to these specific examples. At least one hydrogen atom in the aryl group may be substituted with a substituent.

[0016] [Skeleton] The "skeleton" of the photon upconversion porous body of the present invention is the portion other than the pores of the porous body, and includes at least a donor and an acceptor. The donor and acceptor may be uniformly present in the skeleton, or may be localized in a specific region of the skeleton. The donor and acceptor are not particularly limited as long as they are capable of functioning in the above-described UC luminescence mechanism, but for example, the donors and acceptors shown below can be used.

[0017] [Donor] The donor used in the present invention is preferably a compound that satisfies the following condition (A), and more preferably a compound that satisfies all of the following conditions (A) to (C): (A) The lowest excited singlet energy level S of the acceptor １，Ａ The lowest excited singlet energy level S １，Ｄ and the lowest excited triplet energy level T of the acceptor １，Ａ The lowest excited triplet energy level T １，Ｄ (B) High absorbance. (C) Low absorbance in at least the region of the ultraviolet range that overlaps with the wavelength range of UC light. The molecules of a compound that satisfy condition (A) have the lowest excited singlet energy level S of the acceptor. １，Ａ The lowest excited singlet energy level S １，Ｄ By having this property, it is possible to excite the acceptor to the singlet state using irradiation light having a wavelength longer than that of UC light. In addition, the molecule of the compound satisfying condition (A) has the lowest excited triplet energy level T １，Ａ The lowest excited triplet energy level T １，Ｄ Therefore, by using a compound that satisfies condition (A) as a donor, the mechanism of UC emission shown in Figure 1 can be more reliably achieved. １，Ａ and the lowest excited singlet energy level S of the donor １，Ｄ The difference between (S １，Ａ -S １，Ｄ) is preferably 0.3 to 2 eV, more preferably 0.4 to 1 eV, and even more preferably 0.4 to 0.8 eV. １，Ｄ and the lowest excited triplet energy level T of the acceptor １，Ａ The difference between (T １，Ｄ -T １，Ａ ) is preferably 0.01 to 1 eV, more preferably 0.01 to 0.5 eV, and even more preferably 0.01 to 0.2 eV. １，Ａ , S １，Ｄ and the lowest excited triplet energy level T １，Ａ , T １，Ｄ The measurement method for the lowest excited singlet energy level S １ and the lowest excited triplet energy level T １ The description in the column of "Method of measuring UC light" can be referred to. In addition, these energy levels can also be calculated by density functional theory. Furthermore, a compound that satisfies condition (A) as well as conditions (B) and (C) can efficiently absorb irradiated light but does not absorb UC light. Therefore, by using such a compound as a donor, it is possible to obtain a threshold excitation intensity I ｔｈ The threshold excitation intensity I ｔｈ " refers to the excitation light intensity at the inflection point of a double logarithmic graph showing the dependency of UC luminescence intensity on the excitation light intensity. The lower this value, the lower the excitation light intensity required for UC luminescence. In other words, it means that UC luminescence occurs efficiently. In condition (B), "high absorbance" means that the extinction coefficient is 50,000 M －１ cm －１ In condition (C), "low absorbance" means that the absorption coefficient is 40,000 M or more. －１ cm －１ This means that:

[0018] The donor may be, for example, a compound having a coumarin skeleton (coumarin compound). An example of a coumarin compound that can be used as the donor is a compound represented by the following general formula (1):

[0019] General formula (1)

[0020] In general formula (1), R １ ~R ６ R each independently represents a hydrogen atom or a substituent. １ ~R ６ may be the same or different. １ ~R ５ Examples of substituents that R may have include halogen atoms (e.g., fluorine atoms, chlorine atoms, bromine atoms, iodine atoms), halogenated alkyl groups (e.g., trifluoromethyl groups), halogenated aryl groups (e.g., bromophenyl groups), primary amino groups, secondary amino groups (e.g., alkylamino groups, arylamino groups), tertiary amino groups (e.g., dialkylamino groups, diarylamino groups, alkylarylamino groups), thiocarbonyl groups, hydroxyl groups, alkyl groups, cyano groups, imine groups, benzothiazole groups, benzoxazole groups, benzimidazole groups, furan groups, pyrrole groups, thiophene groups, oxazole groups, imidazole groups, and thiazole groups. ６ Examples of the substituent that R may have include a halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom), an alkoxy group, an alkyl group, an amino group, an alkylamino group, a phenylamino group, a pyridyl group, and a hydroxyl group. １ and R ２ , R ２ and R ３ , R ３ and R ４ , R ４ and R ５may be bonded to each other to form a ring. The ring may be an aromatic ring or an alicyclic ring. Examples of the ring include a benzene ring, a polycyclic aromatic ring formed by condensing two or more benzene rings (e.g., a naphthalene ring, an anthracene ring), a cyclohexadiene ring, a cyclohexene ring, a cyclopentaene ring, a dihydrofuran ring, a heterocycle (e.g., a furan ring, a pyrrole ring, a thiophene ring, an oxazole ring, an imidazole ring, a thiazole ring, a benzothiazole ring, a benzoxazole ring, a benzimidazole ring, a piperidine ring, a pyrrolidine ring, and a ring formed by condensing two or more of these), and a BODIPY ring (boron-dipyrromethene ring). For details and specific examples of the compound represented by general formula (1), see WO2023 / 037848A1

[0028] to

[0030] .

[0021] Specific examples of donors that can be used in the present invention include the following heavy metal-containing compounds.

[0022] Specific examples of donors that can be used in the present invention include the following heavy metal-free compounds.

[0023] [Acceptor] The acceptor of the photon upconversion composition used in the present invention is preferably a compound that satisfies the following condition (D): (D) The lowest excited singlet energy level S of the donor １，Ｄ The lowest excited singlet energy level S １，Ａ and the lowest excited triplet energy level T of the donor １，Ｄ The lowest excited triplet energy level T １，Ａ The acceptor molecule that satisfies condition (D) has the lowest excited singlet energy level S of the donor. １，Ｄ The lowest excited singlet energy level S １，Ａ By having this, it is possible to emit UC light having a shorter wavelength than the excitation light of the donor. In addition, the acceptor molecule that satisfies condition (D) has the lowest excited triplet energy level T １，Ｄ The lowest excited triplet energy level T １，ＡTherefore, by using a compound that satisfies condition (D) as an acceptor, the UC emission mechanism shown in Figure 1 can be more reliably realized. １，Ａ and the lowest excited singlet energy level S of the donor １，Ｄ The difference between (S １，Ａ -S １，Ｄ ) is preferably 0.3 to 2 eV, more preferably 0.4 to 1 eV, and even more preferably 0.4 to 0.8 eV. １，Ｄ and the lowest excited triplet energy level T of the acceptor １，Ａ The difference between (T １，Ｄ -T １，Ａ ) is preferably 0.01 to 1 eV, more preferably 0.01 to 0.5 eV, and even more preferably 0.01 to 0.2 eV. １，Ａ , S １，Ｄ and the lowest excited triplet energy level T １，Ａ , T １，Ｄ The measurement method for the lowest excited singlet energy level S １ and the lowest excited triplet energy level T １ These energy levels can also be calculated by density functional theory.

[0024] Acceptors that can be used include compounds having a fused ring formed by condensing an aromatic ring with a heterocyclic ring (provided that the total number of rings present in the molecule of the compound is 2 to 5 and the compound does not contain a coumarin ring) and substituted polycyclic aromatic hydrocarbon compounds. In the following description, a "compound having a fused ring formed by condensing an aromatic ring with a heterocyclic ring (provided that the total number of rings present in the molecule of the compound is 2 to 5 and the compound does not contain a coumarin ring)" is sometimes referred to as a "polycyclic aromatic heterocompound." Furthermore, the term "substituted polycyclic aromatic hydrocarbon compound" as used herein refers to a polycyclic aromatic hydrocarbon compound in which at least one hydrogen atom is substituted with a substituent, and the substituent substituted on the polycyclic structure formed by condensing benzene rings is not limited to hydrocarbons. Substituted naphthalene compounds and substituted pyrene compounds are preferred. The photon upconversion composition may contain, as an acceptor, one or more compounds selected from the group of compounds consisting of polycyclic aromatic heterocompounds and substituted polycyclic aromatic hydrocarbon compounds. However, in one embodiment of the present invention, the acceptor is a compound other than a naphthalene compound substituted with a substituent containing at least one selected from the group consisting of an alkynyl group, a substituted silyl group, a benzene ring, a heteroaromatic ring, a cyano group, and a halogen atom.

[0025] In the fused ring of the polycyclic aromatic hetero compound used as the acceptor, at least one hydrogen atom may be substituted with a substituent. When the substituent of the fused ring contains a ring, the "total number of rings" in the above "the total number of rings present in the compound molecule is 2 to 5" refers to the sum of the total number of rings constituting the fused ring and the total number of rings contained in the substituent. For example, in the case of the following compound shown as a specific example of a polycyclic aromatic hetero compound in the following section, the total number of rings is 5.

[0026]

[0027] The aromatic ring constituting the fused ring of a polycyclic aromatic heterocyclic compound may be an aromatic ring composed of carbon atoms and hydrogen atoms (aromatic hydrocarbon ring) or an aromatic ring containing a heteroatom (aromatic heterocycle). An example of an aromatic hydrocarbon ring is a benzene ring. Examples of heteroatoms constituting an aromatic heterocycle include a nitrogen atom, an oxygen atom, and a sulfur atom, with a nitrogen atom being preferred. The aromatic heterocycle may contain one or more heteroatoms. When an aromatic heterocycle contains two or more heteroatoms, the heteroatoms may be the same or different. A preferred example of an aromatic heterocycle is a nitrogen-containing aromatic heterocycle having five or six ring members, one to three of which are nitrogen atoms, and a more preferred example is a nitrogen-containing aromatic heterocycle having six ring members, one to three of which are nitrogen atoms. Specific examples of aromatic heterocycles include a pyridine ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, and a triazine ring. The heterocycle constituting the fused ring of the polycyclic aromatic heterocycle may be an aromatic heterocycle or an alicyclic heterocycle. Examples of heteroatoms constituting the heterocycle include a nitrogen atom, an oxygen atom, a sulfur atom, and a cerium atom. The heterocycle may contain one or more heteroatoms. When the heterocycle contains two or more heteroatoms, the heteroatoms may be the same or different. The heterocycle preferably has 5 or 6 ring members, and 1 to 3 of the ring members are heteroatoms. Specific examples of the heterocycle include a pyrrole ring, a pyrroline ring, a pyrazole ring, an imidazole ring, a triazole ring, a pyridine ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, a triazine ring, a thiophene ring, a 2,3-dihydrodiphene ring, a furan ring, a 2,3-dihydrofuran ring, a 1,3-dioxole ring, a 2,3-dihydro-1,4-dioxin ring, an oxazole ring, an isoxazole ring, an oxadiazole ring, a thiazole ring, an isothiazole ring, a thiadiazole ring, and a selenadiazole ring. The number of rings constituting the fused ring may be any of 2 to 5, but is preferably 2 or 3.Specific examples of fused rings constituting polycyclic aromatic hetero compounds are shown below, but the polycyclic aromatic hetero compounds that can be used as acceptors in the present invention are not limited to those having these fused rings.

[0028]

[0029] As described above, at least one hydrogen atom of a fused ring constituting a polycyclic aromatic hetero compound or at least one hydrogen atom of a fused ring constituting a polycyclic aromatic hydrocarbon compound may be substituted with a substituent. The substituent is not particularly limited, but examples thereof include an alkynyl group, a substituted silyl group, an aryl group, a heteroaryl group, and a cyano group. For an explanation of the aryl group, its preferred range, and specific examples, please refer to the description of the "aryl group" above. The alkynyl group may be linear, branched, or cyclic. The alkynyl group preferably has 2 to 20 carbon atoms, more preferably 2 to 10 carbon atoms, and even more preferably 2 to 6 carbon atoms. Examples include an ethynyl group, a propynyl group, and a butynyl group. At least one hydrogen atom of the alkynyl group may be substituted with a substituent. Examples of the substituent include an alkyl group, a halogenated alkyl group, a dialkoxyalkyl group, a substituted silyl group, an aryl group, and a pinacolatoboryl group. For the description, preferred range, and specific examples of the substituted silyl group, please refer to the description of the substituted silyl group as a substituent of a fused ring below. For the description, preferred range, and specific examples of the aryl, please refer to the description of the "aryl group" above. The alkyl group as a substituent of the alkynyl group may be linear, branched, or cyclic, but is preferably linear or branched. The alkyl group preferably has 1 to 20 carbon atoms. Specific examples of linear alkyl groups include methyl, ethyl, and n-propyl groups, as well as long-chain alkyl groups such as dodecyl, tridecyl, tetradecyl, pentadecyl, and hexadecyl groups. Specific examples of branched alkyl groups include branched alkyl groups having 3 to 6 carbon atoms such as isopropyl, isobutyl, sec-butyl, tert-butyl, isopentyl, neopentyl, tert-pentyl, and isohexyl. The halogenated alkyl group as a substituent of the alkynyl group may be a halogenated alkyl group in which all hydrogen atoms of the alkyl group have been substituted with halogen atoms, or may be a partially halogenated alkyl group in which some hydrogen atoms of the alkyl group have been substituted with halogen atoms.For a description of the alkyl group substituted with a halogen atom, its preferred range, and specific examples, please refer to the description of the "alkyl group" above. Examples of halogen atoms include fluorine, chlorine, bromine, and iodine atoms, with fluorine atoms being preferred. A dialkoxyalkyl group as a substituent on an alkynyl group preferably has a structure in which two alkoxy groups are bonded to the terminal carbon atoms of the alkyl group. For a description of the alkyl group constituting a "dialkoxyalkyl group," its preferred range, and specific examples, please refer to the description of the "alkyl group" above. The two alkoxy groups constituting a "dialkoxyalkyl group" may be linear or branched. The alkoxy group preferably has 1 to 20 carbon atoms, more preferably 1 to 10 carbon atoms, and even more preferably 1 to 6 carbon atoms. Specific examples of alkoxy groups include methoxy, ethoxy, n-propoxy, and isopropoxy. The two alkoxy groups constituting a "dialkoxyalkyl group" may be the same or different. The substituted silyl group as a substituent on a fused ring may be a mono-substituted silyl group, a di-substituted silyl group, or a tri-substituted silyl group, with a tri-substituted silyl group being preferred. In di-substituted silyl groups and tri-substituted silyl groups, the multiple substituents may be the same or different. Examples of substituents for the substituted silyl group include alkyl groups and aryl groups. The alkyl group may be linear, branched, or cyclic, with linear or branched being preferred. The number of carbon atoms in the alkyl group may be one or more, but is preferably two or more, and more preferably three or more. Furthermore, when the substituted silyl group is a trialkylsilyl group, the total number of carbon atoms in the three alkyl groups is preferably six or more. There is no particular upper limit on the number of carbon atoms, but it is preferably 20 or less. For a description of the aryl group, its preferred range, and specific examples, please refer to the description of the "aryl group" above. Specific examples of the substituted silyl group include a trimethylsilyl group, a triethylsilyl group, a tri-n-propylsilyl group, a triisopropylsilyl group, and a triphenylsilyl group.The heteroaryl group as a substituent of the fused ring is preferably composed of a monocyclic aromatic heterocycle. Examples of heteroatoms constituting the aromatic heterocycle include nitrogen, oxygen, and sulfur atoms. The aromatic heterocycle may contain one or more heteroatoms. When the aromatic heterocycle contains two or more heteroatoms, the heteroatoms may be the same or different. More preferably, the heteroaryl group is composed of a 5- or 6-membered aromatic heterocycle, 1 to 3 of which are heteroatoms. Specific examples of aromatic heterocycles constituting the heteroaryl group include a pyrrole ring, an imidazole ring, a pyridine ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, a triazine ring, a furan ring, a thiophene ring, an oxazole ring, and a thiazole ring. At least one hydrogen atom of the aromatic heterocycle may be substituted with a substituent.

[0030] The positions of the substituents on the fused ring are not particularly limited, and the number of substitutions may be any number within the range not exceeding the number of substitutable positions. The number of substituents may be selected, for example, from the range of 1 to 4, or from the range of 1 to 3, or may be 1 or 2. For example, when a fused ring containing a benzene ring has two substituents, the positions of the substituents may be ortho-positions relative to each other on the benzene ring, meta-positions relative to each other, or para-positions relative to each other. Furthermore, when a fused ring is substituted with two or more substituents, the substituents may be the same or different.

[0031] Specific examples of acceptors are shown below, but the acceptors that can be used in the present invention should not be construed as being limited by these specific examples. Furthermore, known acceptor compounds, including those described in WO2023 / 037848A1

[0042] , can also be used in the present invention.

[0032]

[0033] A specific example of an acceptor that emits UVB light is the following compound described in Angew. Chem. Int. Ed. 2023, 62, e202215340. In the following formula, TIPS represents a triisopropylsilyl group.

[0034]

[0035] Specific examples of acceptors that emit UVB light include the following compounds:

[0036] (Lowest excited singlet energy level S １ and the lowest excited triplet energy level T １ The lowest excited singlet energy level S of the compound used in the present invention is １ The lowest excited triplet energy level T of the compound used in the present invention can be obtained by measuring the fluorescence spectrum of the compound in solution and converting the wavelength of the fluorescence peak on the shortest wavelength side into an energy value using the following conversion formula. １ can be obtained by dissolving the compound, measuring the phosphorescence spectrum, and converting the wavelength of the phosphorescence peak into an energy value using the following conversion formula. The solvent used to dissolve the compound should be one that can dissolve the compound (e.g., tetrahydrofuran). The concentration of the solution should be one that allows spectrum measurement (e.g., 100 μM). The emission spectrum can be measured using a JASCO FP-8300 made by JASCO Corporation, using a xenon lamp as the excitation light source. Conversion formula: S １ [eV]=1239.85 / λ Ｆ Conversion formula: T １ [eV]=1239.85 / λ Ｐ In the above equation, λ Ｆ is the fluorescence peak wavelength [nm], and λ Ｐ is the phosphorescence peak wavelength [nm].

[0037] [Embodiments of the Skeleton] The skeleton contains at least a donor and an acceptor. The skeleton may be composed of only a donor and an acceptor, or may contain other components. Examples of other components include a matrix resin. Here, "matrix resin" refers to a resin contained in the skeleton and serves as a dispersion medium for at least one of the donor and the acceptor. In a preferred embodiment of the present invention, the skeleton is composed of a material in which the donor is dispersed in the acceptor. In a preferred embodiment of the present invention, the skeleton is composed of a material in which the donor and the acceptor are dispersed in the matrix resin. In one embodiment of the present invention, the donor is present on the surface of the skeleton. Here, the "surface" of the skeleton on which the donor is present refers to both the outer surface of the skeleton and the inner surface surrounding the through-holes of the skeleton. However, the donor only needs to be present on at least a portion of the surface of the skeleton, and may be present throughout the entire surface of the skeleton or on a portion of the surface of the skeleton. However, it is preferable that the donor is present at least on the inner surface surrounding the through-holes. The donor present on the surface of the skeleton may be attached to the surface or may be absorbed from the surface to the interior (present near the surface). In one embodiment of the present invention, the skeleton contains an acceptor, and the donor is present on the surface of the skeleton. In this case, the portion of the skeleton excluding the donor may be composed of only the acceptor, or may be composed of a material in which the acceptor is dispersed in a matrix resin.

[0038] [Matrix Resin] A polymer that is in a solid state at room temperature (25° C.) can be used as the matrix resin. In the present invention, the term “polymer” refers to a polymer compound having structural units derived from a sufficient number of monomers to exhibit a solid state at room temperature (usually a polymer compound having structural units derived from 30 or more monomers).

[0039] While any known polymer can be appropriately selected for use, amorphous polymers are preferred due to their high light transmittance. Amorphous polymers can be confirmed by the absence of a clear melting point. Examples of polymers include acrylic, vinyl, styrene, allyl, divinyl, epoxy, isocyanate, diamine, dicarboxylic acid, dicarboxylic acid chloride, diol, dithiol, cyclic olefin, fluorine-containing, isothiocyanate, bismaleimide, lactone, lactide, and disulfonyl chloride homopolymers, as well as copolymers of two or more of these. For example, polystyrene, poly(alkyl methacrylate), poly(alkyl acrylate), poly(N-alkylacrylamide), and polyvinyl alcohol are preferably used, and bioplastics may also be used. Bioplastics contain substances derived from renewable organic resources as raw materials and can be appropriately selected from those synthesized chemically or biologically. For example, cellulose and protein can be used, with biodegradable biopolymers being particularly preferred. In the present invention, two or more of these polymers may be used in combination. In one embodiment of the present invention, the photon upconversion porous body comprises a matrix resin containing polymethyl methacrylate. In one embodiment of the present invention, the photon upconversion porous body comprises a matrix resin containing polyvinyl alcohol. The degree of polymerization of the polymer can be selected from the range of 10 to 50,000, and may be 10 to 1,000, 1,000 to 10,000, or 10,000 to 50,000. The weight-average molecular weight of the polymer can be selected from the range of 1,000 to 5,000,000, and may be 1,000 to 100,000, 100,000 to 1,000,000, or 1,000,000 to 5,000,000. Here, the weight-average molecular weight of the polymer is the weight-average molecular weight measured by gel permeation chromatography (GPC).

[0040] The polymer may have a glass transition temperature of room temperature (25°C) or higher, or may have a glass transition temperature below room temperature. When a polymer having a glass transition temperature above room temperature is used, the polymer exhibits hard properties, making molecular diffusion difficult, and energy transfer between compound molecules occurs mainly by energy diffusion. On the other hand, when a polymer having a glass transition temperature below room temperature is used, the polymer exhibits soft properties, making energy transfer by molecular diffusion possible. The glass transition temperature of a polymer can be measured using a differential scanning calorimeter.

[0041] Furthermore, when a photon upconversion porous body is produced by the first or second production method described below, it is preferable to select a matrix resin polymer that is highly resistant to the solvent used to dissolve and remove the porous template. Furthermore, for photon upconversion porous bodies used in a flow system or batch system that uses an organic solvent, it is preferable to select a matrix resin polymer that is highly resistant to the organic solvent. In this case, to increase the resistance to the organic solvent, a crosslinked structure may be introduced between the polymer chains of the matrix resin, or a coating layer such as a silica coating (a coating layer containing silicon dioxide) may be formed on the surface of the skeleton. In one aspect of the present invention, the matrix resin comprises an epoxy-based polymer having a crosslinked structure. In one aspect of the present invention, the skeleton comprises a matrix resin containing polyvinyl alcohol, and the surface of the skeleton has a coating layer, for example, a silica coating.

[0042] [Coating Layer] As described above, a silica coat can be used as the coating layer formed on the skeleton. The coating layer formed on the skeleton may also be formed by treating the surface of the skeleton with a silane coupling agent. Examples of the silane coupling agent include compounds represented by the following general formula (3): General Formula (3) R １ ｎ Six （４－ｎ） (In general formula (3), X represents a hydrolyzable group that generates a silanol group upon hydrolysis, and R １represents a hydrolyzable group that generates a silanol group upon hydrolysis, or a substituted or unsubstituted alkyl group. n is an integer of 1 to 3. The silane coupling agent represented by general formula (3) forms a coating layer by reacting the silanol group or silyl group generated by hydrolysis of X with the functional group on the surface of the core particle. In the general formula, X and R １ Examples of the "hydrolyzable group that generates a silanol group" that R can take include alkoxy groups such as methoxy and ethoxy groups, and halogen groups. １ Examples of the substituent of the substituted alkyl group that can be taken include a halogen group, an amino group, an epoxy group, and a phenyl group. Examples of the silane coupling agent represented by general formula (3) include tetraethoxysilane, triethoxyalkylsilane, diethoxydialkylsilane, ethoxytrialkylsilane, tetramethoxysilane, trimethoxyalkylsilane, dimethoxydialkylsilane, methoxytrialkylsilane, and trichloroalkylsilane. The silane coupling treatment for forming a coating layer on the skeleton can be carried out according to a conventional method.

[0043] The thickness of the coating layer formed on the skeleton can be selected, for example, from the range of 1.0 to 500.0 nm, may be selected from the range of 1.0 to 10.0 nm, may be selected from the range of 10.0 to 100.0 nm, or may be selected from the range of 100.0 to 500.0 nm.

[0044] [Donor and Acceptor Blending Ratio and Content] In a skeleton embodiment in which the donor is dispersed in the acceptor, and in a skeleton embodiment in which the donor and acceptor are dispersed in a matrix resin, the donor to acceptor molar ratio [(number of donor moles / number of acceptor moles) × 100] is preferably 0.01 to 20%, more preferably 0.1 to 10%, and even more preferably 1 to 5%. When the donor has low absorbance at the emission wavelength of the acceptor, the donor concentration can be increased to allow for better absorption of excitation light.

[0045] In the embodiment of the skeleton in which the donor and the acceptor are dispersed in the matrix resin, the total amount of the donor and the acceptor is the ratio of the total amount of the donor, the acceptor, and the matrix resin (R calculated by the following formula: ＤＡ ) is preferably 10% by weight or more, may be 20% by weight or more, 30% by weight or more, or may be 40% by weight or more. ＤＡ may be 90% by weight or less, 80% by weight or less, or 70% by weight or less. ＤＡ = [(W Ｄ +W Ａ ) / (W Ｄ +W Ａ +W Ｐ ) × 100 W Ｄ : Donor content W Ａ : Acceptor content W Ｐ : Polymer content

[0046] In an embodiment in which the donor is present on the surface of the skeleton, the amount of the donor is the ratio R Ｄ The ratio R is preferably 0.001% by weight or more, may be 0.01% by weight or more, 0.1% by weight or more, or may be 1% by weight or more. Ｄ In an embodiment in which the donor is present on the surface of the skeleton and the acceptor is dispersed in the matrix resin, the content of the acceptor is determined by the ratio of the acceptor content to the total amount of the acceptor and the matrix resin (R calculated by the following formula: Ａ ) is preferably 10% by weight or more, may be 20% by weight or more, 30% by weight or more, or may be 40% by weight or more. Ａ may be 90% by weight or less, 80% by weight or less, or 70% by weight or less. Ａ = [(W Ａ ) / (W Ａ +W Ｐ ) × 100 W Ａ : Acceptor content W Ｐ : Polymer content

[0047] [Other Components] The skeleton may further contain other components in addition to the donor, acceptor, and matrix resin, such as a colorant and an antioxidant.

[0048] [Through Holes] The photon upconversion porous body of the present invention is characterized by having through holes. In the present invention, "through holes" refers to continuous holes that penetrate from one outer surface of the photon upconversion porous body to the other outer surface. In other words, "through holes" in the present invention are continuous holes that are open on at least one outer surface and the other outer surface of the porous body. Here, the through holes may be open on two outer surfaces, or on three or more outer surfaces. By having such through holes, when the porous body is placed in a flow path and a fluid is flowed through it, the fluid easily passes from one side to the other through the through holes, exhibiting high permeability. Therefore, the photon upconversion porous body of the present invention can also be used in flow systems, and has a wide range of applications and is highly useful. The through holes may be those that penetrate linearly from one outer surface to the other outer surface, or those that penetrate irregularly from one outer surface to the other outer surface, or may have a three-dimensionally connected structure, or may have a three-dimensionally co-continuous structure formed by the continuous pores and the skeleton.

[0049] The through-pore diameter of the photon upconversion porous body is, for example, 0.1 to 100 μm, preferably 1 to 10 μm. The through-pore diameter here refers to the average pore diameter, and is calculated by measuring the diameter of a sphere that can pass through each pore present within a specific surface of the photon upconversion porous body and dividing the sum by the number of measured pores. The surface to be measured can be a surface passing through the center of gravity of the photon upconversion porous body, but a specific exposed surface may be selected for measurement for simplicity. The photon upconversion porous body may have pores closed at one or both ends in addition to through-pores, but in one embodiment of the present invention, there are no pores with a maximum diameter of 1 μm or more and closed at both ends. In a preferred embodiment of the present invention, there are no pores with a maximum diameter of 0.1 μm or more and closed at both ends. In a preferred embodiment of the present invention, all of the pores in the photon upconversion porous body are spatially connected, and no closed pores exist.

[0050] [Shape and porosity of photon upconversion porous body] In the photon upconversion porous body of the present invention, the shape and size of the porous body are not particularly limited and can be appropriately selected depending on the application. Examples of the outer diameter shape of the porous body include film, filter, block, cylindrical, and granular shapes. The size of the porous body may be in the range of 1 mm to 10 m in maximum diameter, for example, 5 mm to 10 cm, or 20 cm to 10 m. In one aspect of the present invention, the photon upconversion porous body is film-shaped and has through-holes that open on the front and back surfaces of the film. In one aspect of the present invention, the photon upconversion porous body is filter-shaped and has through-holes that open on the front and back surfaces of the filter. In one aspect of the present invention, the photon upconversion porous body is a cube-shaped block and has through-holes that open on at least two surfaces. In one aspect of the present invention, the photon upconversion porous body is cylindrical and has through-holes that open on the top and bottom surfaces. In one embodiment of the present invention, the photon upconversion porous body is granular and has through-holes that open at at least two locations on the particle surface. Each through-hole in these embodiments may be open on only two faces, or on three or more faces. One embodiment of the photon upconversion porous body of the present invention is a monolithic porous body. Here, "monolithic" refers to a porous body having three-dimensionally interconnected pores, and is formed by a three-dimensional co-continuous structure of interconnected pores and a material skeleton.

[0051] The porosity of the photon upconversion porous body of the present invention is, for example, 1 to 20%, for example, 10 to 50%, for example, 30 to 80%. The porosity of the porous body can be determined by measuring the volume and mass of the entire porous body including the pores and from the specific gravity of the skeleton.

[0052] (Substances that the photon upconversion porous body should not contain) The photon upconversion porous body of the present invention preferably does not contain heavy metals. Here, the "heavy metals" in "does not contain heavy metals" refer to substances with a specific gravity of 4 g / cm ３ The term "heavy metal-free" means that the composition is substantially free of heavy metals in any form, including heavy metals as constituent elements of compounds and heavy metals as simple substances, and does not exclude the inclusion of heavy metals as unavoidable impurities. Here, "substantially free of heavy metals" means that the content of heavy metals in the composition is 0.1 ppm or less.

[0053] <Light Irradiation Method> Next, the light irradiation method of the present invention will be described. The light irradiation method of the present invention involves irradiating a photon upconversion porous body having a framework containing a donor and an acceptor and through-holes with light, and irradiating the resulting photon upconversion light (UC light) onto a substance present in the through-holes. In the following description, the "substance" in the present invention will be referred to as the "irradiated substance." For an explanation of the photon upconversion porous body used in the present invention, please refer to the description in the <Photon Upconversion Porous Body> section above. The photon upconversion porous body used in the present invention has a high degree of design freedom in terms of its shape and dimensions. For example, it can take various shapes such as a film, filter, block, or granule, and can be manufactured in a variety of shapes, from fine granular shapes to large-area or large-surface-area shapes. Therefore, the shape and dimensions of the photon upconversion porous body can be easily adjusted to match the shape and size of the flow channel or batch-type container described below.

[0054] In the present invention, the irradiated substance present in the through-holes is, for example, a substance that undergoes some kind of reaction due to UC light irradiated from the photon upconversion porous body. The reaction caused by the irradiated substance may be any reaction caused by UC light, such as a photochemical reaction. Examples of photochemical reactions include photoisomerization reactions, photocyclization reactions, photodimerization reactions, photodecomposition reactions, and photo-Fries transition reactions. Examples of the irradiated substance include raw materials for organic synthesis using photochemical reactions, precursors for chemical modification using photochemical reactions, and substances that are subject to sterilization by ultraviolet irradiation (e.g., photodimerization of thymine in DNA).

[0055] The irradiated substance present in the through-holes may be supplied from outside the photon upconversion porous body or may be applied to the inner surface surrounding the through-holes during the manufacturing process of the photon upconversion porous body, but is preferably supplied from outside. When the irradiated substance is supplied into the through-holes from outside, the light irradiation method of the present invention may be performed in a flow system or a batch system. In a preferred embodiment of the present invention, the light irradiation method of the present invention is performed using a flow system. In a flow system, a photon upconversion porous body is placed in a flow path of a fluid containing the irradiated substance, and while the fluid is passing through the porous body, the photon upconversion porous body is irradiated with light whose wavelength overlaps with the absorption wavelength range of the donor. This light irradiation activates the UC emission mechanism, and the irradiated substance passing through the through-holes is irradiated with UC light. As a result, for example, a desired reaction occurs in the irradiated substance to produce a reactant, which is then separated and collected downstream of the flow path to obtain the target reactant. In a flow system, the irradiated material is continuously supplied into the microscopic space of the through-hole, and UC light is irradiated from the inner surface surrounding the through-hole. This allows for uniform and efficient UC light irradiation of the irradiated material, and the UC light irradiation time for the irradiated material can be precisely controlled. In a batch system, a photon upconversion porous body is immersed in a fluid containing the irradiated material, the fluid is stirred as needed, and the porous body is irradiated with light whose wavelength overlaps the absorption wavelength range of the donor. This light irradiation activates the UC emission mechanism, and the UC light is irradiated onto the irradiated material that has permeated the through-hole. As a result, for example, a desired reaction occurs in the irradiated material, generating a reactant. This can be separated from other components of the porous body and fluid to obtain the desired reactant.

[0056] The fluid containing the irradiated substance may be a melt (melt) of the irradiated substance above its melting point, or a solution or dispersion containing the irradiated substance. The solvent for the solution or dispersion may be an organic solvent, water, or a mixed solvent of organic solvent and water, but it is preferable to select a solvent that the porous body has high resistance to. If water is selected as the solvent, the present invention can be applied to a wide range of reactions in water, including reactions related to biology and agriculture, and is particularly useful. Furthermore, if an organic solvent is selected as the solvent, the present invention can be applied to reactions of poorly water-soluble or water-insoluble substances, and can also be applied to various reactions including industrial reactions. The organic solvent can be appropriately selected from known organic solvents, and can be selected from, for example, aromatics such as benzene, toluene, xylene, and chlorobenzene; ethers such as diethyl ether, dibutyl ether, tetrahydrofuran, 1,4-dioxane, dimethoxyethane, and diethylene glycol dimethyl ether; esters such as methyl acetate, ethyl acetate, butyl acetate, and ethyl propionate; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; hydrocarbons such as hexane, heptane, octane, and nonane; halogenated hydrocarbons such as dichloromethane, chloroform, and 1,2-dichloroethane; organic acids such as formic acid, acetic acid, and propionic acid; polar solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone; and mixed solvents thereof.

[0057] The content of the irradiated substance in the fluid is, for example, 0.01M to 0.1M, for example, 0.1M to 1M, for example, 1M to 10M.

[0058] In a preferred embodiment of the present invention, the light irradiated onto the photon upconversion porous body is visible light. The visible light may be a single light having a maximum emission wavelength at a specific wavelength in the visible region, a composite light obtained by combining multiple visible light beams with different maximum emission wavelengths, or a composite light obtained by combining light beams with continuous wavelengths in the visible region. Examples of the irradiation source include sunlight, LED, Xe lamp, and laser. The irradiation intensity is 0.1 to 1000 mW / cm. ２ is preferably 0.5 to 100 mW / cm ２ More preferably, it is 1 to 50 mW / cm ２ The irradiation time is a time that allows the desired photoreaction to occur, and may be, for example, one minute or more.

[0059] <Light Irradiation Channel> The light irradiation channel of the present invention is a channel through which a fluid containing a substance flows, and the photon upconversion porous body is disposed in the channel. The photon upconversion porous body is a porous body having a skeleton containing a donor and an acceptor and through-holes. For an explanation of the photon upconversion porous body, please refer to the description in the above <Photon Upconversion Porous Body> section, and for an explanation of the fluid containing a substance, please refer to the corresponding description in the above <Light Irradiation Method> section. The shape and size of the channel used in the present invention are not particularly limited, and examples include column-type channel, tubular channel, and chip-type channel. The diameter of the channel may be, for example, in the range of 1 mm to 10 m, for example, in the range of 5 mm to 10 cm, or for example, in the range of 20 cm to 10 m.

[0060] <First manufacturing method for photon upconversion porous body> Next, the first manufacturing method for photon upconversion porous body of the present invention will be described. The first manufacturing method for photon upconversion porous body of the present invention is a method for manufacturing a photon upconversion porous body containing a donor and an acceptor and having through-holes, and includes the steps of filling a porous mold having through-holes with a fluid containing the donor and acceptor, solidifying the fluid, and then dissolving and removing the porous mold. For an explanation of the photon upconversion porous body manufactured by the present invention and the donor and acceptor used in the present invention, please refer to the description in the <Photon upconversion porous body> section above.

[0061] The porous template having through-holes used in the present invention is a template whose internal space has a shape corresponding to the skeleton of the target photon upconversion porous material. In one embodiment of the present invention, the porous template is a monolith, for example, a porous silica monolith. Since the porous silica monolith is easily dissolved in a solvent in the process of dissolving and removing the porous template, it is preferably a porous silica monolith obtained by low-temperature firing of a gel prepared by a sol-gel method. The temperature for low-temperature firing is, for example, 100 to 300°C, for example, 300 to 600°C, for example, 600 to 900°C.

[0062] The fluid containing the donor and acceptor used in the present invention may be a melt at or above the melting point of the donor and acceptor mixture, or may be a solution or dispersion containing the donor and acceptor. The fluid may also contain, in addition to the donor and acceptor, a monomer material that serves as a structural unit of the matrix resin. The monomer material may contain one type of monomer or two or more types of monomers. For an explanation of the matrix resin, please refer to the description in the above section [Polymer as Matrix Resin]. The solvent for the solution and dispersion may be appropriately selected from known solvents. For specific examples, please refer to the description of "Solvent for Solution and Dispersion" in the above section [Light Irradiation Method].

[0063] To produce a photon upconversion porous material using the production method of the present invention, first, a fluid containing a donor and an acceptor is filled into the porous mold and the fluid is solidified. The fluid may be solidified by cooling or by solid precipitation due to a polymerization reaction of the monomer material. Next, the porous mold is dissolved and removed. This results in a photon upconversion porous material that corresponds to the internal shape of the porous mold. To dissolve the porous mold, a solvent that dissolves the porous mold but does not dissolve the photon upconversion porous material can be used. Examples of solvents include alkaline solutions such as an aqueous solution of an alkali metal hydroxide or an aqueous solution of an alkaline earth metal hydroxide. Preferably, an aqueous solution of an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide is used, and more preferably, an aqueous solution of sodium hydroxide is used.

[0064] <Second Production Method of Photon Upconversion Porous Material> The second production method of the photon upconversion porous material of the present invention is a method for producing a photon upconversion porous material containing a donor and an acceptor and having through-holes, and includes the steps of filling a porous mold having through-holes with a fluid containing an acceptor, solidifying the fluid, dissolving and removing the porous mold, and attaching the donor to the surface of the resulting porous material. For an explanation of the photon upconversion porous material produced by the present invention and the donor and acceptor used in the present invention, please refer to the description in the <Photon Upconversion Porous Material> section above.

[0065] The acceptor-containing fluid used in the present invention may be a melt of the acceptor at or above its melting point, or a solution or dispersion containing the acceptor. The acceptor-containing fluid may consist solely of the acceptor, or may contain a monomer material that will serve as a structural unit of the matrix resin. The monomer material may contain one type of monomer, or two or more types of monomers. For an explanation of the matrix resin, please refer to the description in the above section "Polymer as Matrix Resin." The solvent for the solution and dispersion may be appropriately selected from known solvents. For specific examples, please refer to the description of "Solvent for Solution and Dispersion" in the above section "Light Irradiation Method."

[0066] To produce a photon upconversion porous body using the production method of the present invention, first, a fluid containing an acceptor is filled into the porous mold and solidified. The fluid may be solidified by cooling or by solid precipitation due to a polymerization reaction of the monomer material. Next, the porous mold is dissolved and removed. This results in an acceptor-containing porous body corresponding to the internal shape of the porous mold. For an explanation of the porous mold and the porous mold solvent, please refer to the description in the "First Production Method" section above. Next, a donor is attached to the surface of the obtained acceptor-containing porous body to obtain a photon upconversion porous body. Here, the "surface" of the porous body refers to both the outer surface of the porous body and the inner surface of the through-holes inside the porous body (the inner surface surrounding the through-holes of the skeleton). However, the donor only needs to be attached to at least a portion of the surface of the porous body. It may be attached to the entire surface of the porous body or to a portion of the surface, but it is preferable to attach it to at least the inner surface of the through-holes. The donor can be attached to the surface of the porous material by, for example, immersing the acceptor-containing porous material in a micellar solution of the donor, then removing the porous material from the micellar solution, washing, and drying. The donor attached to the surface of the acceptor-containing porous material may remain on the surface or may be absorbed into the framework of the completed photon upconversion porous material.

[0067] <Third Production Method of Photon Upconversion Porous Material> The third production method of the photon upconversion porous material of the present invention is a method for producing a photon upconversion porous material having a skeleton containing a donor and an acceptor and through-holes, and includes the steps of preparing a solution in which a donor, an acceptor, a monomer, and a polymerization initiator are dissolved in two or more solvents, polymerizing the monomer to cause phase separation into a solid phase having the skeleton and a liquid phase, and then removing the liquid phase. For an explanation of the photon upconversion porous material produced by the present invention and the donor and acceptor used in the present invention, please refer to the description in the <Photon Upconversion Porous Material> section above.

[0068] When preparing a solution according to the third production method, two or more solvents are used. It is preferable to select one or more good solvents and one or more poor solvents. A nonpolar aromatic solvent such as toluene can be preferably selected as the good solvent. A polar solvent such as propanol can be preferably selected as the poor solvent. The amount of the good solvent used is preferably less than that of the poor solvent. The upper limit can be set to, for example, 30% by volume or less, 25% by volume or less, or 20% by volume or less of the total solvent amount, and the lower limit can be set to, for example, 5% by volume or more, 10% by volume or more, or 15% by volume or more. Using a larger amount of the good solvent tends to result in finer pores in the resulting photon upconversion porous material. On the other hand, using an excessively large amount of the good solvent tends to reduce the solubility of the donor and acceptor. The prepared solution can be ultrasonicated or nitrogen-bubbled before polymerizing the monomer. Polymerizing the monomer according to the third production method separates the solid phase of the polymer from the liquid phase of the solvent. At this time, the polymer becomes a solid phase with a porous skeleton, and phase separation occurs with the liquid phase filling the porous pores. Polymerization is carried out under conditions that facilitate the formation of such a porous skeleton. For example, polymerization can be carried out at 50 to 100°C for 1 to 24 hours. After polymerization, the liquid phase is removed. At this time, the solvent used in the polymerization reaction may be exchanged for another solvent. For example, solvent exchange can be carried out by immersion in ethanol. Solvent removal can be carried out by selecting an appropriate means from among conventional solvent removal methods, such as drying under reduced pressure. According to the third production method, a photon upconversion porous material can be easily produced because it does not require the use of a porous silica monolith. The third production method is useful in that it is highly reproducible and allows for control of the porous structure.

[0069] The features of the present invention will be explained in more detail below with reference to examples and comparative examples. The materials, amounts used, ratios, treatment details, treatment procedures, etc. shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be interpreted as being limited by the specific examples shown below. In the following examples, a spectrophotometer (JASCO: V-780) was used to measure the absorption spectrum, and a spectrofluorometer (JASCO: FP-8300) was used to measure the emission spectrum. UC efficiency η ＵＣ was calculated by a relative method using the following compound D1 as a standard substance. This relative method utilizes the phosphorescence quantum yield of the compound D1 solution, the absorbance and emission spectrum of each measurement solution, the excitation light intensity during measurement, and the refractive index of the solvent, and a multichannel spectrometer (MCPD-9800 manufactured by Otsuka Electronics Co., Ltd.) was used to measure the emission spectrum. A fluorescence lifetime measurement device (Quantaurus-Tau C11367-02 / C11567-01 manufactured by Hamamatsu Photonics KK) was used to measure the UC emission lifetime.

[0070] [Donors and Acceptors (Photon Upconversion Compositions), and Polymers Used in the Examples] The donors, acceptors, and polymers used in the examples are shown below.

[0071] acceptor

[0072] (Production of Porous Silica Monolith) In this example, a porous silica monolith produced by the following sol-gel method was used as the porous template. Urea (450 mg) and polyethylene glycol (PEG 10000: Sigma-Aldrich) (575 mg) were added to 10 mM aqueous acetic acid solution (5 mL) and stirred to obtain a solution. Tetramethoxysilane (2.5 mL) was added to this solution in an ice bath and stirred for 90 minutes. This reaction solution was poured into a straight polypropylene pipe (inner diameter: 4 mm or 6 mm) (it can be freely molded by transferring it to any container) and left overnight in a water bath at 30 °C to gel. The resulting gel was heated at 110 °C for 4 hours, cooled to room temperature, removed from the straight pipe, and immersed in water five times and in a 2:1 water / ethanol solution three times, each for half a day, to perform solvent exchange. The washed gel was dried in the atmosphere and then calcined at 600 °C for 5 hours to obtain a white porous silica monolith. A scanning electron microscope (SEM) photograph of the porous silica monolith is shown in FIG.

[0073] Example 1: Preparation and Evaluation of UC Porous Body 1 Comprising a UC Composition Consisting of Compounds D1 and A1 and Polystyrene (Using a Porous Silica Monolith) The porous silica monolith used in this example, the composite formed in this preparation process, and the shape of the UC porous body 1 are shown in Figure 3. First, a solution of azobisisobutyronitrile initiator (2 mg), Compound A1 (23 mg, 47 μmol), and Compound D1 (0.47 μmol) dissolved in styrene (200 mg) was subjected to nitrogen bubbling for 2 minutes, followed by the addition of porous silica monolith (5 mg), sealing, and allowing to stand for 30 minutes to allow the solution to penetrate and fill the porous silica monolith. The silica monolith filled with the solution was heated in a water bath at 90°C for 6 hours to carry out a polymerization reaction. After cooling to room temperature, it was washed with ethanol and dried overnight. The composite of this polymer and silica monolith was immersed in 1 M aqueous NaOH solution (1 mL) for 1 week to dissolve and remove the silica monolith. The remaining polymer was immersed in water for one day, a process repeated three times to exchange the solvent, and then dried under reduced pressure to obtain UC porous material 1. An SEM photograph of UC porous material 1 is shown in Figure 4. The SEM photograph confirmed that UC porous material 1 had a bicontinuous structure on the micrometer scale.

[0074] [Evaluation of UC characteristics] The UC porous body 1 produced in Example 1 was subjected to a blue laser (λ ＥＸ : 445 nm) excitation intensity of 1.7 to 773 Wcm －２ The UC emission spectrum was measured by changing the UC efficiency in the range of . The measured UC emission spectrum is shown in Figure 5. The measurement was performed by placing a 425 nm short wavelength pass filter between the sample and the spectrometer. ＵＣ was 0.15%.

[0075] Example 2: Preparation and Evaluation of UC Porous Body 2 Having Compound D2 Adhered to the Surface of a Porous Body of Compound A2 Figure 6 shows an outline of the porous body (monolith) of Compound A2 formed in this example and the UC porous body 2 having Compound D2 attached to the surface of this porous body. Porous silica monolith (10 mg) and Compound A2 (100 mg) were sealed in a glass tube under reduced pressure and heated to 230°C, above the melting point of Compound A2, for 60 minutes to fill the porous silica monolith with a molten solution of Compound A2. The porous silica monolith filled with the molten solution was cooled to room temperature to solidify Compound A2, after which excess Compound A2 was removed. The monolith was then immersed in a 1M aqueous NaOH solution (1 mL) for one week to dissolve and remove the silica monolith. The remaining molded body was immersed in water for half a day three times to perform solvent exchange, followed by drying under reduced pressure to obtain a porous body (monolith) of Compound A2. An SEM photograph of the porous body of Compound A2 is shown in Figure 7. Next, this porous body (3.5 mg) was immersed in an aqueous micellar solution of compound D2 (25 μM, water: 350 μL) for 2 hours. After immersion, the porous body was removed from the aqueous micellar solution, washed three times with water, and then vacuum dried to obtain UC porous body 2, in which compound D2 was attached to the surface of the porous body of compound A2. An SEM image of UC porous body 2 is shown in Figure 8. The SEM image confirmed that UC porous body 2 has a micrometer-scale bicontinuous structure. Furthermore, powder X-ray diffraction, thermogravimetric analysis, and luminescence property measurements confirmed that the obtained UC porous body 2 had compound D2 uniformly adsorbed on the surface of the porous body of compound A2, and it was also confirmed that energy transfer occurred from compound D2 to compound A2.

[0076] [Evaluation of UC characteristics] The UC emission spectrum of the UC porous body 2 produced in Example 2 measured under the same conditions as in Example 1 is shown in FIG. ｔｈ is 705.9 mW / cm ２ , UC emission lifetime τ Ｔ was 345 μs.

[0077] Example 3: Preparation and Evaluation of UC Porous Body 3 Comprising a UC Composition Composed of Compound D1 and Compound A1 and Polystyrene (No Porous Silica Monolith Used) Figure 10 shows an outline of the changes caused by polymerization and solvent removal in this example, as well as the resulting porous body 3. A solution containing azobisisobutyronitrile initiator (2 mg), Compound A1 (35 mg, 71.6 μmol), Compound D1 (1.43 μmol), styrene (100 μL), divinylbenzene (100 μL), toluene (50 μL), and 2-propanol (250 μL) was ultrasonically treated for 15 minutes and then subjected to nitrogen bubbling for 2 minutes. The solution was heated at 90°C in a water bath or oven for 5 hours, cooled to room temperature, and then immersed in ethanol for 12 hours to exchange the solvent. The solution was then dried under reduced pressure at 80°C for 6 hours to obtain UC Porous Body 3. An SEM photograph of the resulting porous body 3 is shown in Figure 11.

[0078] [Evaluation of UC characteristics] The UC emission spectrum of the UC porous body 3 produced in Example 3 measured under the same conditions as in Example 1 is shown in FIG. ｔｈ is 0.98 mW / cm ２ , UC emission lifetime τ Ｔ is 5.42ms, UC efficiency η ＵＣ was 0.43%.

[0079] The photon upconversion porous material of the present invention can also be applied to a flow system. Therefore, according to the present invention, UC light irradiation in a flow system becomes possible in various fields that utilize photochemical reactions, which can greatly contribute to improving reaction accuracy and reaction efficiency. Therefore, the present invention has high industrial applicability.

Claims

1. A photon upconversion porous material having a framework containing donors and acceptors and through-holes.

2. The photon upconversion porous body according to claim 1, wherein the through-pore diameter of the porous body is 0.1 to 100 μm.

3. The photon upconversion porous body of claim 1, wherein the donor is dispersed in the acceptor.

4. The photon upconversion porous body according to claim 1, wherein the donor is present on the surface of the framework.

5. The photon upconversion porous body according to claim 1, further comprising a matrix resin in the skeleton portion.

6. The photon upconversion porous body according to claim 5, wherein the acceptor is dispersed in the matrix resin.

7. The photon upconversion porous body according to claim 6, wherein the donor is further dispersed in the matrix resin.

8. The photon upconversion porous body according to claim 1, wherein the framework is monolithic.

9. The photon upconversion porous body according to claim 1, which absorbs visible light and emits ultraviolet light.

10. The photon upconversion porous body according to claim 9, which emits ultraviolet light having a wavelength of 280 to 320 nm.

11. A light irradiation method comprising irradiating the photon upconversion porous body according to any one of claims 1 to 10 with light, and irradiating the resulting photon upconversion light onto a substance present within the through-holes.

12. The light irradiation method according to claim 11, wherein the substance is supplied into the through-holes from outside the photon upconversion porous body.

13. The light irradiation method according to claim 11, wherein the photon upconversion porous body is irradiated with light while a fluid containing the substance is transmitted through the photon upconversion porous body.

14. A flow path for light irradiation, comprising a photon upconversion porous body according to any one of claims 1 to 10 disposed in a flow path for a substance-containing fluid to flow.

15. A method for producing a photon upconversion porous body having a skeleton containing a donor and an acceptor and through holes, the method comprising the steps of filling a fluid containing the donor and the acceptor into a porous mold having through holes, solidifying the fluid, and then dissolving and removing the porous mold to form the skeleton.

16. The method of claim 15, wherein said fluid further comprises a monomer, and said solidifying is accomplished by polymerizing said monomer.

17. A method for producing a photon upconversion porous body having a skeleton containing a donor and an acceptor and through holes, the method comprising the steps of filling a porous mold having through holes with a fluid containing the acceptor, solidifying the fluid, and then dissolving and removing the porous mold, and attaching the donor to the surface of the resulting porous body to form the skeleton.

18. A method for producing a photon upconversion porous body having a skeleton containing a donor and an acceptor and through holes, the method comprising: preparing a solution in which the donor, the acceptor, a monomer and a polymerization initiator are dissolved in two or more solvents; polymerizing the monomer to cause phase separation into a solid phase having the skeleton and a liquid phase; and removing the liquid phase.

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