Method for manufacturing light up-conversion organic film, device for manufacturing light up-conversion organic film, and light up-conversion organic film

Abstract

The present invention implements: a precursor holding step (S1) in which a powder precursor containing a triplet sensitizer and an organic light-emitting material is held in a holding space of a precursor holding unit having a holding space having a height in the Z direction; a pressing step (S2) in which the powder precursor is pressed in the Z direction; and a temperature adjustment step for adjusting the temperature of the powder precursor by heating a first temperature, which is the temperature of the first end of the powder precursor, and a second temperature, which is the temperature of the second end of the powder precursor, to a temperature equal to or higher than the melting point of the organic light-emitting material, with the-X-side end of the powder precursor being a first end and the + X-side end being a second end, while maintaining the temperature difference between the first temperature and the second temperature. And the first temperature and the second temperature are gradually reduced to be lower than the freezing point of the organic light-emitting material.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing an upconversion organic film, an upconversion organic film manufacturing apparatus, and an upconversion organic film. Background Art

[0002] As a technology for converting low-energy light into high-energy light, upconversion has attracted much attention. For example, in Non-Patent Document 1, in a combination of a sensitizer (e.g., PtOEP) having a large intersystem crossing rate constant from the lowest excited singlet state to the lowest excited triplet state and a luminescent molecule (e.g., diphenylanthracene (DPA)), the following mechanism has been proposed: luminescent molecules (DPA) excited to the lowest excited triplet state by energy transfer from the sensitizer undergo triplet-triplet annihilation (TTA) with each other to generate the lowest excited singlet state and emit light.

[0003] Technologies related to upconversion are described in, for example, Patent Documents 1 to 2 and Non-Patent Documents 2 to 7 in addition to Non-Patent Document 1.

[0004] In addition, Non-Patent Documents 6 to 7 disclose the manufacture of an upconversion organic film. Specifically, after dissolving a sensitizer and a luminescent molecule in a solvent, the solvent is evaporated to mix the sensitizer and the luminescent molecule. Then, the mixture is dropped onto a substrate, heated and dissolved in an inert atmosphere, and then quenched to generate an upconversion organic film.

[0005] Prior Art Documents

[0006] Patent Documents

[0007] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2020-111751

[0008] Patent Document 2: U.S. Patent No. 10950803 Specification

[0009] Non-Patent Documents

[0010] Non-Patent Document 1: Journal of Applied Physics, 101, 023101 (2007)

[0011] Non-Patent Document 2: J. Phys. Chem. Lett., 2013, 4, 4113-4118

[0012] Non-Patent Document 3: J. Phys. Chem. C, 2014, 118, 14256-14265

[0013] Non-Patent Document 4: Mater. Horiz., 2017, 4, 83-87

[0014] Non-Patent Document 5: J. Mater. Chem. C, 2018, 6, 5609-5615

[0015] Non-Patent Document 6: J. Mater. Chem. C, 2014, 2, 2837-2841

[0016] Non-Patent Document 7: ACS Appl. Mater. Interfaces 2016, 8, 15732-15740 Summary of the Invention

[0017] Problems to be Solved by the Invention

[0018] In Non-Patent Documents 6 to 7 above, after dissolving a sensitizer and a luminescent molecule in an organic solvent, the organic solvent was volatilized to obtain a mixture of the sensitizer and the luminescent molecule. However, there are concerns about the environmental impact due to the use of organic solvents, and a more environmentally friendly method is desired.

[0019] In addition, in the methods of Non-Patent Documents 6 to 7 in which the whole mixture is heated and then quenched, as an amorphous glass, an upconversion organic film formed by solidifying a melt was fabricated, but there is a problem of low upconversion efficiency. Therefore, a high-quality upconversion organic film and a method for manufacturing the same are desired.

[0020] In addition, in order to efficiently and effectively utilize sunlight, the application of upconversion organic films has also been studied. The ultraviolet light (UV light) contained in sunlight is composed of high-energy photons and is used for various purposes. For example, ultraviolet light is used for photocatalyst generation of green hydrogen and hydrocarbons, photopolymerization, disinfection, etc. However, among the photons contained in sunlight on the ground, only about 4% constitute ultraviolet light, so it hinders the efficient and effective utilization of sunlight. Therefore, an upconversion organic film that can effectively convert visible light into ultraviolet light with an excitation threshold intensity equal to or lower than the intensity of sunlight on the earth's surface is desired.

[0021] An object of the present invention is to provide a method for manufacturing an upconversion organic film, an upconversion organic film manufacturing apparatus, and an upconversion organic film that impose a small burden on the environment and can manufacture a high-quality upconversion organic film.

[0022] Another object of the present invention is to provide an upconversion organic film that can stably upconvert light in the visible light region into light in the ultraviolet light region in the atmosphere and exhibits a high upconversion quantum efficiency at an excitation light intensity lower than the intensity of sunlight irradiated on the earth's surface (for example, an intensity about 0.3 times the sunlight intensity).

[0023] Means for Solving the Problems

[0024] One embodiment of the method for manufacturing an upconversion organic film according to the present invention comprises the following steps: a precursor holding step of holding a powder precursor containing a triplet sensitizer and an organic light-emitting material in the holding space of a precursor holding portion having a holding space of a specified height; a pressing step of pressing the powder precursor in the height direction of the holding space; and a temperature adjusting step of heating the temperature of one end side in the axial direction of the powder precursor, i.e., the first temperature, and the temperature of the other end side in the axial direction of the powder precursor, i.e., the second temperature, to above the melting point of the organic light-emitting material, and then gradually decreasing the first temperature and the second temperature while maintaining the temperature difference between the first temperature and the second temperature until the temperatures are lower than the freezing point of the organic light-emitting material, with one direction orthogonal to the height direction as the axial direction.

[0025] In the method for manufacturing an upconversion organic film according to one embodiment of the present invention, preferably, a temperature decreasing rate for gradually decreasing the temperature of the powder precursor is preset with respect to the temperature difference, and the larger the temperature difference, the faster the temperature decreasing rate.

[0026] One embodiment of the method for manufacturing an upconversion organic film according to the present invention comprises the following steps: a precursor holding step of holding a powder precursor containing a triplet sensitizer and an organic light-emitting material in the holding space of a precursor holding portion having a holding space of a specified height; a pressing step of pressing the powder precursor in the height direction of the holding space; and a temperature adjusting step of relatively moving a heating member having a temperature gradient along the axial direction from a high temperature zone above the melting point of the organic light-emitting material to a low temperature zone below the freezing point of the organic light-emitting material with respect to the precursor holding portion in the axial direction.

[0027] In the method for manufacturing an upconversion organic film according to one embodiment of the present invention, preferably, the pressing step presses the powder precursor with the setting environment of the precursor holding portion being in a reduced pressure state.

[0028] In the method for manufacturing an upconversion organic film according to one embodiment of the present invention, preferably, the crystal of the organic light-emitting material has uniaxial orientation.

[0029] In the method for manufacturing an upconversion organic film according to one embodiment of the present invention, preferably, the organic light-emitting material contains an oxazole derivative, and the triplet sensitizer contains a coumarin derivative.

[0030] One aspect of the present invention relates to an apparatus for manufacturing an upconversion organic film, which includes: a precursor holding part having a holding space with a predetermined height, for holding a powder precursor containing a triplet sensitizer and an organic light-emitting material in the holding space; a pair of clamping parts for clamping the precursor holding part in the height direction; a pressing part for pressing at least one of the pair of clamping parts in a direction approaching each other; and a first heating mechanism. Taking a direction orthogonal to the height direction as the axial direction, taking one end side of the powder precursor in the axial direction as the first end, taking the other end side of the powder precursor in the axial direction as the second end, taking the temperature of the first end as the first temperature, and taking the second end as the second temperature, the first heating mechanism heats the first temperature and the second temperature of the powder precursor to different temperatures to generate a temperature gradient along the axial direction. After heating the first temperature and the second temperature above the melting point of the organic light-emitting material, while maintaining the temperature difference between the first temperature and the second temperature, the first temperature and the second temperature are gradually decreased to below the freezing point of the organic light-emitting material.

[0031] In the apparatus for manufacturing an upconversion organic film according to one aspect of the present invention, preferably, the first heating mechanism includes: a first heating part provided on one end side of the clamping part in the axial direction; a second heating part provided on the other end side of the clamping part in the axial direction, capable of being driven independently of the first heating part; and a cooling part provided on the other end side of the clamping part in the axial direction for cooling the second end.

[0032] In the apparatus for manufacturing an upconversion organic film according to one aspect of the present invention, preferably, the first heating part is a first rod heater respectively embedded in one end side of the pair of clamping parts in the axial direction, and the second heating part is a second rod heater respectively embedded in the other end side of the pair of clamping parts in the axial direction.

[0033] In the apparatus for manufacturing an upconversion organic film according to one aspect of the present invention, preferably, the precursor holding part is a pair of substrates separated in the height direction with a spacer, and the holding space is formed by the gap between the pair of substrates. A buffer member for absorbing stress in the height direction is provided between the pair of clamping parts and the precursor holding part.

[0034] In the apparatus for manufacturing an upconversion organic film according to one aspect of the present invention, preferably, a decompression mechanism is further included for maintaining the ambient environment of the precursor holding part, the pair of clamping parts, the pressing part, and the first heating mechanism in a decompressed state.

[0035] In the upconversion organic film manufacturing apparatus according to an aspect of the present invention, preferably, an adiabatic material is further provided which is grounded on the side opposite to the side of the pair of clamping portions that clamp the precursor holding portion.

[0036] The upconversion organic film manufacturing apparatus according to an aspect of the present invention includes: a precursor holding portion having a holding space with a predetermined height, for holding a powder precursor containing a triplet sensitizer and an organic light-emitting material in the holding space; a pair of guiding portions which are members that press and clamp the precursor holding portion in the height direction, guiding the precursor holding portion in a direction orthogonal to the height direction as an axial direction so as to be able to move relatively along the axial direction; a second heating mechanism which heats the guiding portions to generate a temperature gradient along the axial direction from a high-temperature region above the melting point of the organic light-emitting material to a low-temperature region below the freezing point of the organic light-emitting material; and a moving mechanism which relatively moves the precursor holding portion in the axial direction with respect to the guiding portions.

[0037] In the upconversion organic film manufacturing apparatus according to an aspect of the present invention, preferably, the precursor holding portion is a pair of substrates separated in the height direction with a spacer therebetween, and the holding space is formed by the gap between the pair of substrates. The pair of guiding portions are a pair of guiding plates that clamp the precursor holding portion in the height direction. The second heating mechanism heats the guiding plates to generate the temperature gradient such that the temperatures at positions opposite to each other in the pair of guiding plates are the same. The moving mechanism relatively moves the precursor holding portion with respect to the guiding portions by pressing the precursor holding portion into the space between the pair of guiding plates in the axial direction.

[0038] In the upconversion organic film manufacturing apparatus according to an aspect of the present invention, preferably, the precursor holding portion includes a pair of substrates separated in the height direction with a spacer therebetween and a pair of support plates that clamp the pair of substrates and are longer than the substrates in the axial direction. The holding space is formed by the gap between the pair of substrates. The pair of guiding portions are constituted by arranging a plurality of pairs of rollers in the axial direction. The rollers in the pair of rollers are paired in the height direction and rotate about a rotation axis orthogonal to the height direction and the axial direction. The precursor holding portion is clamped by the pair of rollers paired in the height direction. The moving mechanism relatively moves the precursor holding portion in the axial direction with respect to the pair of guiding portions by rotating the rollers. The second heating mechanism individually adjusts the temperatures of the pairs of rollers arranged in the axial direction such that the pairs of rollers with higher temperatures in the high-temperature region to the pairs of rollers with lower temperatures in the low-temperature region are arranged in sequence along the axial direction.

[0039] In the light upconversion organic film manufacturing apparatus according to one aspect of the present invention, preferably, the second heating mechanism heats the guiding portion so as to generate a temperature gradient along the axial direction in which a low temperature region, a high temperature region, and a low temperature region are sequentially arranged.

[0040] According to one aspect of the present invention, there is provided a light upconversion organic film which contains a triplet sensitizer and an organic light emitting material, the organic light emitting material has ultraviolet light emitting property, and the light upconversion organic film is a film having crystallinity.

[0041] In the light upconversion organic film according to one aspect of the present invention, preferably, the triplet sensitizer absorbs excitation light to generate excited triplet excitons, and the organic light emitting material emits light having a maximum peak in a wavelength region shorter than the maximum peak wavelength on the longest wavelength side of the absorption spectrum of the triplet sensitizer and below 400 nm.

[0042] In the light upconversion organic film according to one aspect of the present invention, preferably, the crystal of the organic light emitting material has uniaxial orientation.

[0043] In the light upconversion organic film according to one aspect of the present invention, preferably, the organic light emitting material contains an oxazole derivative.

[0044] In the light upconversion organic film according to one aspect of the present invention, the fluorescence quantum yield of the organic light emitting material is preferably 40% or more.

[0045] In the light upconversion organic film according to one aspect of the present invention, preferably, the triplet sensitizer does not contain a metal atom in the molecule.

[0046] In the light upconversion organic film according to one aspect of the present invention, preferably, the triplet sensitizer contains only hydrogen atoms, carbon atoms, oxygen atoms, and nitrogen atoms in the molecule.

[0047] In the light upconversion organic film according to one aspect of the present invention, preferably, the triplet sensitizer contains a coumarin derivative.

[0048] In the light upconversion organic film according to one aspect of the present invention, preferably, the molar ratio of the triplet sensitizer to the organic light emitting material is 1:1000 to 1:100000.

[0049] According to one aspect of the present invention, there can be provided a method for manufacturing a light upconversion organic film, a light upconversion organic film manufacturing apparatus, and a light upconversion organic film which are less burdensome to the environment and can manufacture a high-quality light upconversion organic film.

[0050] According to one aspect of the present invention, there can be provided an upconversion organic film capable of stably upconverting light in the visible light region to light in the ultraviolet light region in the atmosphere and exhibiting a high upconversion quantum efficiency at an excitation light intensity lower than the intensity of sunlight irradiated onto the earth's surface (for example, an intensity about 0.3 times the intensity of sunlight). BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 FIG. is a diagram showing a general configuration of an organic film manufacturing apparatus according to the first embodiment.

[0052] Figure 2 FIG. is a block diagram showing a general configuration of the organic film manufacturing apparatus according to the present embodiment.

[0053] Figure 3 FIG. is an enlarged cross-sectional view showing a holding portion of a precursor holding portion and a pair of clamping portions according to the present embodiment.

[0054] Figure 4 FIG. is a flowchart showing a method for manufacturing an upconversion organic film according to the present embodiment.

[0055] Figure 5 FIG. is a diagram showing temperature changes of a pair of clamping portions in a temperature adjustment step according to the present embodiment.

[0056] Figure 6 FIG. is a diagram showing a cooling state of a powder precursor in a temperature adjustment step according to the present embodiment.

[0057] Figure 7 FIG. is a schematic diagram showing a general configuration of an organic film manufacturing apparatus according to the second embodiment.

[0058] Figure 8 FIG. is a schematic diagram showing a general configuration of an organic film manufacturing apparatus according to a modification of the present embodiment.

[0059] Figure 9 FIG. is a flowchart showing a method for manufacturing an upconversion organic film according to the present embodiment.

[0060] Figure 10 FIG. is a schematic diagram showing a general configuration of an organic film manufacturing apparatus according to the third embodiment.

[0061] Figure 11 FIG. is a flowchart showing a method for manufacturing an upconversion organic film according to the present embodiment.

[0062] Figure 12 FIG. is a schematic diagram showing an upconversion mechanism in an upconversion organic film.

[0063] Figure 13AIt is a graph showing the temperature change of a pair of clamping parts when forming the upconversion organic film related to Example 1.

[0064] Figure 13B It is a graph showing the temperature change of a pair of clamping parts when forming the upconversion organic film related to Example 2.

[0065] Figure 13C It is a graph showing the temperature change of a pair of clamping parts when forming the upconversion organic film related to Example 3.

[0066] Figure 13D It is a graph showing the temperature change of a pair of clamping parts when forming the upconversion organic film related to Example 4.

[0067] Figure 13E It is a graph showing the temperature change of a pair of clamping parts when forming the upconversion organic film related to Example 5.

[0068] Figure 14 They are optical microscope images of the respective upconversion organic films related to the examples.

[0069] Figure 15 It is a graph showing the powder X-ray diffraction (PXRD) patterns of the PPO powder and the upconversion organic film powder.

[0070] Figure 16 It is a graph showing the crystal structure of PPO obtained by Pawley and Rietveld analysis.

[0071] Figure 17 It is a graph showing the photophysical properties of the upconversion organic film and CBDAC.

[0072] Figure 18A It is a schematic diagram of the device for measuring photophysical properties.

[0073] Figure 18B It is an enlarged cross-sectional view of the sample for photophysical measurement.

[0074] Figure 19A It is a graph showing the dependence of the upconversion quantum efficiency on the excitation intensity at a wavelength of 440 nm.

[0075] Figure 19B It is a graph showing the dependence of the upconversion quantum efficiency on the excitation intensity at a wavelength of 440 nm.

[0076] Figure 20 It is a graph showing the excitation threshold intensity (I th ) of the upconversion organic film and the molar ratio M A / M S of the organic light-emitting material relative to the triplet sensitizer.

[0077] Figure 21 It is a graph showing the sunlight intensity dependence of the upconversion luminescence intensity.

[0078] Figure 22 It is a graph showing the light stability of the upconversion organic film.

[0079] Figure 23 It is a schematic diagram of an experimental method showing an example of the practicality of the upconversion organic film. Detailed implementation mode

[0080] [First implementation mode]

[0081] Hereinafter, an upconversion organic film manufacturing apparatus and an upconversion organic film manufacturing method according to a first implementation mode of the present invention will be described. It should be noted that the upconversion organic film manufacturing apparatus is simply abbreviated as the organic film manufacturing apparatus.

[0082] Figure 1 It is a cross-sectional view showing a general configuration of the organic film manufacturing apparatus 10 of the present implementation mode. Figure 2 It is a block diagram showing the organic film manufacturing apparatus 10 according to the present implementation mode.

[0083] The organic film manufacturing apparatus 10 of the present implementation mode is a manufacturing apparatus for manufacturing an upconversion organic film. As Figure 1 shown, it includes a precursor holding portion 11, a pair of holding portions (first holding portion 12A, second holding portion 12B) that hold the precursor holding portion 11, a first heating mechanism 13 (see Figure 2 ), a pressing mechanism 14, a decompression mechanism 15 (see Figure 2 ), and an adjustment controller 16 that adjusts the first heating mechanism 13 (see Figure 2 ).

[0084] The precursor holding part 11 holds the powder precursor 111 for forming the light up-conversion organic film. The powder precursor 111 is a powder containing a triplet sensitizer and an organic light-emitting material. In the present embodiment, a powder precursor 111 with a molar ratio of triplet sensitizer to organic light-emitting material of 1:1000 to 1:100000 is used. It should be noted that, in the present embodiment, as an example, as the triplet sensitizer, a powder of CBDAC (3,3-carbonylbis(7-diethylaminocoumarin)) is used, and as the organic light-emitting material, a powder of PPO (2,5-diphenyloxazole) having a uniaxial orientation crystal is used. It should be noted that the triplet sensitizer and the organic light-emitting material that can be used in the manufacturing apparatus and manufacturing method of the present embodiment are not limited to the examples of CBDAC and PPO. For example, they can be selected and used from the triplet sensitizer and the organic light-emitting material described in the fourth embodiment below.

[0085] Figure 3 It is an enlarged cross-sectional view of the holding part of the precursor holding part 11, which is the precursor holding part 11 and a pair of clamping parts 12A and 12B.

[0086] As Figure 3 shown, the precursor holding part 11 includes a pair of glass substrates 112A and 112B and a spacer 113 that maintains a predetermined distance between the pair of glass substrates 112A and 112B. The space surrounded by these glass substrates 112A and 112B and the spacer 113, that is, the gap between the pair of glass substrates 112A and 112B, constitutes a holding space 114 for accommodating the powder precursor 111.

[0087] Here, the mutually opposing surfaces of the pair of glass substrates 112A and 112B are taken as the XY plane, and the direction orthogonal to the XY plane is taken as the Z direction.

[0088] The first clamping part 12A and the second clamping part 12B are members that clamp the precursor holding part 11 from the Z direction. The first clamping part 12A is arranged on the +Z side of the precursor holding part 11, and the second clamping part 12B is arranged on the -Z side of the precursor holding part 11. Preferably, these first clamping part 12A and second clamping part 12B are made of a material with high thermal conductivity such as metal.

[0089] The surface of the first clamping part 12A opposite to the second clamping part 12B and the surface of the second clamping part 12B opposite to the first clamping part 12A each have an XY plane opposite to the glass substrates 112A and 112B. In addition, between the first clamping part 12A and the second clamping part 12B, a holding member 121 for holding the precursor holding part 11 is arranged. The holding member 121 can be integrally provided with the first clamping part 12A or the second clamping part 12B, for example.

[0090] The holding member 121 is provided, for example, with a recess or a through hole for holding the precursor holding portion 11 at the central portion in the XY plane. In the recess or the through hole of the holding member 121, an O-ring 122 is disposed as a buffer member when the precursor holding portion 11 is clamped by the first clamping portion 12A and the second clamping portion 12B. The precursor holding portion 11 is disposed on the inner diameter side surrounded by the O-ring 122.

[0091] The O-ring 122 has a thickness in the Z direction that is equal to or greater than the height of the holding member 121 in the Z direction. It is clamped and pressed by the first clamping portion 12A and the second clamping portion 12B, and thus elastically deformed to the same thickness as the precursor holding portion 11. Therefore, when the precursor holding portion 11 is held by the first clamping portion 12A and the second clamping portion 12B, a sealed space is formed on the inner diameter side of the O-ring 122, and the pressure is reduced by a pressure reducing mechanism 15 described later, so that the inner diameter side of the O-ring 122 is maintained in a reduced pressure environment.

[0092] The first heating mechanism 13 adjusts the temperature of the first clamping portion 12A and the second clamping portion 12B.

[0093] Here, one axial direction along the XY plane is defined as the X direction. The first heating mechanism 13 includes: a first heating portion 131 provided on the -X side (one end side in the X direction) of the first clamping portion 12A and the second clamping portion 12B; a second heating portion 132 provided on the +X side (the other end side in the X direction) of the first clamping portion 12A and the second clamping portion 12B; and a cooling portion 133 connected to the +X side of the first clamping portion 12A and the second clamping portion 12B in the X direction.

[0094] The first heating portion 131 is a member that heats the -X side of the first clamping portion 12A and the second clamping portion 12B. For example, as Figure 1 shown, the first heating portion 131 is composed of first rod heaters 131A and 131B respectively embedded in the first clamping portion 12A and the second clamping portion 12B at positions closer to the -X side than the holding member 121. The first rod heater 131A embedded in the first clamping portion 12A and the first rod heater 131B embedded in the second clamping portion 12B are at the same position in the X direction and are arranged side by side along the Z direction. These first rod heaters 131A and 131B are adjusted to the same temperature, for example, by being connected to the same drive circuit.

[0095] The second heating portion 132 is a member that heats the +X side of the first clamping portion 12A and the second clamping portion 12B. For example, as Figure 1As shown, the second heating unit 132 is composed of second rod heaters 132A and 132B respectively embedded in the first clamping part 12A and the second clamping part 12B at positions on the +X side of the holding part 121. The second rod heater 132A embedded in the first clamping part 12A and the second rod heater 132B embedded in the second clamping part 12B are at the same position in the X direction and are arranged side by side along the Z direction. These second rod heaters 132A and 132B are adjusted to the same temperature, for example, by being connected to the same drive circuit. In addition, the second rod heaters 132A and 132B are driven by a drive circuit independent of the first rod heaters 131A and 131B that make up the first heating unit 131 and can be adjusted to a temperature different from that of the first heating unit 131.

[0096] The cooling unit 133 is composed of a heat transfer part 133A and a cooling element 133B.

[0097] The heat transfer part 133A is a member with high thermal conductivity connected to the +X side of the first clamping part 12A and the second clamping part 12B, and is composed of a metal foil such as copper foil, for example.

[0098] The cooling element 133B cools the heat transferred to the heat transfer part 133A. As the cooling element 133B, an element capable of appropriately adjusting the cooling efficiency is preferably used. For example, a Peltier element, a fan using air cooling or water cooling, a heat sink, etc. can be used.

[0099] In addition, the first clamping part 12A and the second clamping part 12B are each provided with a plurality of temperature sensors 134(I) to 134(V) along the X direction. As these temperature sensors 134(I) to 134(V), for example, thermocouples embedded inside the first clamping part 12A and the second clamping part 12B can be exemplified.

[0100] Furthermore, the first clamping part 12A and the second clamping part 12B are clamped by a pair of heat insulating materials 135 from the Z direction. Specifically, the heat insulating materials 135 are respectively arranged at positions overlapping the holding part 121 when viewed from the Z direction on the +Z side of the first clamping part 12A and the -Z side of the second clamping part 12B.

[0101] In such a first heating mechanism 13, the heating temperature in the first heating part 131, the heating temperature in the second heating part 132, and the cooling temperature in the cooling part 133 can be adjusted respectively. Thereby, for the first clamping part 12A and the second clamping part 12B, a temperature gradient along the X direction can be generated, and the temperature difference ΔT between the ±X sides of the first clamping part 12A and the second clamping part 12B can be maintained constant, and the overall temperature of the first clamping part 12A and the second clamping part 12B can be adjusted up and down. It should be noted that the "constant" mentioned here allows for errors within a specified range, and is not limited to a strict temperature difference ΔT. In the up and down adjustment of the temperature, as long as the temperature difference ΔT is approximately constant.

[0102] In addition, by clamping the first clamping part 12A and the second clamping part 12B with the heat insulating material 135, heat loss caused by heat release in the region between the first heating part 131 and the second heating part 132 (the position overlapping with the precursor holding part 11 in the Z direction) is suppressed.

[0103] The pressing mechanism 14 corresponds to the pressing part of the present invention, and presses the first clamping part 12A and the second clamping part 12B in the direction of approaching each other. That is, for the pair of glass substrates 112A, 112B of the precursor holding part 11 clamped by the first clamping part 12A and the second clamping part 12B, they are pressed in the direction of approaching each other, and a load is applied to the powder precursor 111 in the holding space 114.

[0104] Here, as the pressing mechanism 14, a configuration that presses both the first clamping part 12A and the second clamping part 12B in the direction of approaching each other can be adopted, or a configuration that presses either the first clamping part 12A or the second clamping part 12B toward the other can be adopted.

[0105] In the present embodiment, as Figure 1 shown, through holes 124 penetrating in the Z direction are formed at the ±X side ends of the first clamping part 12A and the second clamping part 12B, and fixing shafts 141 are inserted into these through holes 124. The +Z sides of these fixing shafts 141 are fixed to the fixing table 142.

[0106] In addition, the movable table 143 is penetrated by the fixed shaft 141, and the heat insulating material 135, the first clamping portion 12A, the second clamping portion 12B on the +Z side and the heat insulating material 135 on the -Z side are clamped by the movable table 143 and the fixed table 142. And, on the -Z side of the movable table 143, a biasing member 144 such as a spring that biases the movable table 143 toward the fixed table 142 is arranged. By the acting force of the biasing member 144, the movable table 143 is pressed toward the fixed table 142. Thus, as described above, the precursor holding portion 11 is held from the Z direction by the first clamping portion 12A and the second clamping portion 12B, and the powder precursor 111 clamped by the pair of glass substrates 112A, 112B is pressed in the Z direction. In addition, the pair of heat insulating materials 135 are respectively in contact with the first clamping portion 12A and the second clamping portion 12B to suppress heat loss.

[0107] It should be noted that, in the present embodiment, although an example in which the movable table 143 is pressed toward the fixed table 142 by the biasing member 144 is shown, it may also be configured such that the movable table 143 is pressed toward the fixed table 142 by a driving force output from a driving source such as a motor.

[0108] Specifically, the pressure reducing mechanism 15 is as Figure 2 shown as a vacuum chamber 151 and a vacuum pump 152. In the present embodiment, the above-mentioned first clamping portion 12A, second clamping portion 12B, first heating mechanism 13, pressing mechanism 14 and precursor holding portion 11 are arranged in the vacuum chamber 151. And, the pressure reducing mechanism 15 discharges the gas in the vacuum chamber 151 by using the vacuum pump 152, thereby setting the inside of the vacuum chamber 151 to a reduced pressure state, preferably a vacuum state.

[0109] In the present embodiment, during the process of making the first clamping portion 12A and the second clamping portion 12B approach each other by the pressing mechanism 14, the inside of the vacuum chamber 151 is depressurized, thereby discharging the air between the pair of glass substrates 112A, 112B of the precursor holding portion 11. Thus, the sealed space surrounded by the O-ring 122 is maintained in a reduced pressure state (preferably a vacuum state), and when the powder precursor 111 is melted to form the light up-conversion organic film, the mixing of bubbles can be suppressed, and a higher quality light up-conversion organic film can be manufactured.

[0110] As Figure 2 shown, the adjustment controller 16 adjusts the first heating mechanism 13, the pressing mechanism 14 and the pressure reducing mechanism 15.

[0111] Specifically, the adjustment controller 16 includes: a first heating drive circuit 161 connected to the first heating unit 131, a second heating drive circuit 162 connected to the second heating unit 132, a cooling drive circuit 163 connected to the cooling unit 133, a pressure reduction drive circuit 164 that adjusts the vacuum pump 152, and a processor 165 that outputs an adjustment signal to these drive circuits. As the pressing mechanism 14, when pressing the powder precursor 111 using a drive source such as a motor, a drive circuit that adjusts the drive source can be provided.

[0112] By making the first heating drive circuit 161 and the second heating drive circuit 162 independent of each other, as described above, it is possible to independently adjust the heating temperature in the first heating unit 131 and the heating temperature in the second heating unit 132, and a temperature gradient along the X axis can be generated.

[0113] The pressure reduction drive circuit 164 drives the vacuum pump 152, thereby reducing the pressure in the vacuum chamber 151.

[0114] In addition, as described above, the processor 165 maintains the temperature difference ΔT between the heating temperature of the first heating unit 131 and the heating temperature of the second heating unit 132, and raises and lowers the temperature of the entire first clamping portion 12A and the second clamping portion 12B. At this time, preferably, the processor 165 adjusts the cooling drive circuit 163 based on the temperatures measured by the respective temperature sensors 134(I) to 134(V), and performs feedback adjustment on the cooling efficiency of the cooling unit 133.

[0115] [Manufacturing Method of Photoluminescent Upconversion Organic Film]

[0116] Next, a manufacturing method of a photoluminescent upconversion organic film using the organic film manufacturing apparatus 10 as described above will be described.

[0117] Figure 4 It is a flowchart showing the manufacturing method of the photoluminescent upconversion organic film of the present embodiment.

[0118] In the present embodiment, when manufacturing a photoluminescent upconversion organic film, first, a powder precursor 111 is prepared and held in the precursor holding portion 11 (step S1: precursor holding step).

[0119] As described above, the powder precursor 111 is a powder containing a triplet sensitizer and an organic light emitting material. Then, the powder precursor 111 prepared as described above is filled into the gap (holding space 114) between a pair of glass substrates 112A and 112B disposed opposite to each other with a spacer 113 interposed therebetween.

[0120] Next, the precursor holding portion 11 is fixed to the holding member 121, and the second clamping portion 12B is urged toward the first clamping portion 12A by the urging member 144 (Step S2: pressing process). Thereby, the powder precursor 111 held between the pair of glass substrates 112A and 112B is pressed in the Z direction.

[0121] In addition, in this step S2, the decompression mechanism 15 decompresses the inside of the vacuum chamber 151, and the powder precursor 111 is pressed in the decompressed state.

[0122] Then, the adjustment controller 16 adjusts the first heating mechanism 13 via the first heating drive circuit 161, the second heating drive circuit 162, and the cooling drive circuit 163 to heat the first clamping portion 12A and the second clamping portion 12B, thereby implementing a temperature adjustment step of adjusting the temperature of the powder precursor 111.

[0123] Figure 5 It is a diagram showing the temperature changes of the first clamping portion 12A and the second clamping portion 12B in the temperature adjustment step. In Figure 5 the line L1 is the temperature measured by the temperature sensor 134(I) of the first clamping portion 12A disposed at the end on the -X side. The line L2 is the temperature measured by the temperature sensor 134(II) of the first clamping portion 12A arranged as the second one counted from the -X side. The line L3 is the temperature measured by the temperature sensor 134(III) of the first clamping portion 12A arranged as the third one (center) counted from the -X side. The line L4 is the temperature measured by the temperature sensor 134(IV) of the first clamping portion 12A arranged as the second one counted from the +X side. The line L5 is the temperature measured by the temperature sensor 134(V) of the first clamping portion 12A disposed at the end on the +X side. The line L6 is the temperature measured by the temperature sensor 134(II) of the second clamping portion 12B arranged as the second one counted from the -X side.

[0124] The line L7 is the temperature measured by the temperature sensor 134(III) of the second clamping portion 12B arranged as the third one counted from the -X side. The line L8 is the temperature measured by the temperature sensor 134(IV) of the second clamping portion 12B arranged as the second one counted from the +X side.

[0125] In the temperature adjustment step, first, in order to melt the powder precursor 111, the processor 165 heats the temperature of the pair of clamping portions (the first clamping portion 12A, the second clamping portion 12B) to at least the melting point T of the organic light-emitting material (PPO) melt(PPO) or more (Step S3: Figure 5During t0 to t1). At this time, the processor 165 causes the temperature difference ΔT between the -X side end and the +X side end of a pair of clamping parts (the first clamping part 12A and the second clamping part 12B) to reach a constant value. For example, the first clamping part 12A and the second clamping part 12B are heated at a heating rate of 5°C / min.

[0126] Here, the temperature of the -X side end (the first end) of the powder precursor 111 held by the precursor holding part 11 is represented by the line L2 measured by the temperature sensor 134(II), and the temperature of the +X side end (the second end) of the powder precursor 111 is represented by the line L4 measured by the temperature sensor 134(IV). As long as the temperature of the second heating part 132 set to a lower temperature than the first heating part 131 is the melting point T melt(PPO) above, the part (the part corresponding to the temperature sensors 134(II) to 134(IV)) where the powder precursor 111 is disposed reaches the melting point T melt(PPO) above.

[0127] In addition, in the present embodiment, the temperature difference ΔT between the two ends of the pair of clamping parts 12A and 12B is maintained constant and the temperature of the pair of clamping parts is raised and lowered. At this time, the temperature difference ΔT' between the temperature of the -X side end of the powder precursor 111 (the first temperature, the temperature measured by the temperature sensor 134(II)) and the temperature of the +X side end of the powder precursor 111 (the second temperature, the temperature measured by the temperature sensor 134(IV)) is also maintained constant and raised and lowered. That is, the operation of raising and lowering the pair of clamping parts 12A and 12B while maintaining the temperature difference ΔT is the same as the operation of raising and lowering the temperature of the powder precursor 111 while maintaining the temperature difference ΔT' between the first temperature of the -X side end and the second temperature of the +X side end of the powder precursor 111.

[0128] Next, the processor 165 maintains the temperatures of the first heating part 131 and the second heating part 132 for a specified time (step S4: Figure 5 during t1 to t2). As a result, the powder precursor 111 held by the precursor holding part 11 melts. The time of step S4 is the time for melting the powder precursor 111, and can be appropriately set according to the amount of the powder precursor 111 held by the precursor holding part 11, the types and molar ratios of the triplet sensitizer and the organic light-emitting material constituting the powder precursor 111, etc.

[0129] Then, the processor 165 reduces the temperatures of the first heating part 131 and the second heating part 132 at a specified cooling rate while maintaining the temperature difference ΔT between the first heating part 131 and the second heating part 132 (step S5: Figure 5 during t2 to).

[0130] Figure 6A diagram showing the temperature-lowering state of the powder precursor 111 based on step S5.

[0131] In the present embodiment, while maintaining the temperature difference ΔT, the first heating unit 131 and the second heating unit 132 are cooled, as Figure 6 shown, the powder precursor 111 is cooled in a state where a temperature gradient is generated. Therefore, the powder precursor 111 is cooled from the +X side to the -X side in turn to a temperature lower than the freezing point T solid(PPO) Here, in the present embodiment, as the organic light-emitting material, PPO having uniaxial orientation is used. Therefore, the molten powder precursor 111 is cooled and crystallized in turn along the X-axis, which is the direction of the temperature gradient.

[0132] The cooling rate in step S5 is appropriately set based on the types, molar ratios, and temperature difference ΔT (or temperature difference ΔT´) of the triplet sensitizer and the organic light-emitting material constituting the powder precursor 111 held in the precursor holding unit 11. For example, in the present embodiment, as the triplet sensitizer, CBDAC is used, as the organic light-emitting material, PPO is used, the molar ratio is 1:30000, and the temperature gradient along the X direction is 20 °C / 24 mm (= 0.83 °C / mm). As long as the length along the X direction from the first heating unit 131 to the second heating unit 132 is 24 mm, the temperature difference ΔT = 20 °C can be set. At this time, it is preferable to set the cooling rate to -3 °C / min. By increasing the temperature difference ΔT (or temperature difference ΔT´), the cooling rate can be increased, and the same crystal growth can be achieved.

[0133] Thereby, a light up-conversion organic film having a crystal orientation along the X direction is manufactured.

[0134] It should be noted that in the present embodiment, a plurality of temperature sensors 134(I) to 134(V) are arranged along the X direction. Therefore, in the temperature adjustment steps of steps S3 to S5, the heating temperature of the first heating unit 131, the heating temperature of the second heating unit 132, and the cooling efficiency of the cooling unit 133 can be feedback-adjusted so that the temperatures of the respective temperature sensors 134(I) to 134(V) reach the desired temperatures, and the temperature difference ΔT and the temperature difference ΔT´ can be adjusted with high precision.

[0135] [Function and Effect of the Present Embodiment]

[0136] The manufacturing method of the light up-conversion organic film of the present embodiment implements a precursor holding step (step S1), a pressing step (step S2), and a temperature adjustment step (steps S3 to S5).

[0137] In the precursor holding step, a powder precursor 111 containing a triplet sensitizer and an organic light-emitting material is held in a holding space 114 at a specified height provided in a precursor holding unit 11.

[0138] In the pressing step, the powder precursor 111 is pressed along the height direction (Z direction) of the holding space 114.

[0139] In the temperature adjustment step, the first temperature at the -X side end and the second temperature at the +X side end of the powder precursor 111 are heated to the melting point T of the organic light-emitting material. melt(PPO) After the above (step S3 to step S4), while maintaining the temperature difference ΔT' between the first temperature and the second temperature, the first temperature and the second temperature are gradually decreased to be lower than the freezing point T of the organic light-emitting material. solid(PPO) (step S5).

[0140] In such a method for manufacturing a light up-conversion organic film, through step S5, the powder precursor 111 is cooled in sequence from the +X side of the molten powder precursor 111 to be lower than the freezing point T. solid(PPO) , a light up-conversion organic film formed by crystal growth along one axial direction can be manufactured. Thereby, a light up-conversion organic film with high light up-conversion efficiency and good quality can be manufactured.

[0141] In addition, in the present embodiment, for example, it is not necessary to drop an organic solvent in which a triplet sensitizer and an organic light-emitting material are dissolved onto a substrate and volatilize it as in the past. That is, since it is not necessary to use an organic solvent, the environmental burden in the manufacture of the light up-conversion organic film can be reduced.

[0142] In the present embodiment, with respect to the temperature difference ΔT (or the temperature difference ΔT'), a temperature reduction rate at which the temperature of the powder precursor 111 is gradually decreased is preset in advance. The larger the temperature difference ΔT (or the temperature difference ΔT'), the faster the temperature reduction rate.

[0143] Thereby, the crystallization of the molten powder precursor 111 can be appropriately induced, and a higher-quality light up-conversion organic film can be manufactured.

[0144] In the present embodiment, in the pressing step (step S2), the setting environment of the precursor holding unit 11 is set to a reduced pressure state by a pressure reducing mechanism 15, and the powder precursor 111 is pressed.

[0145] Thereby, in the temperature adjustment step, it is possible to suppress the inclusion of bubbles in the light up-conversion organic film undergoing crystallization, and a higher-quality light up-conversion organic film can be manufactured.

[0146] In the present embodiment, the crystal of the organic light-emitting material has uniaxial orientation.

[0147] Therefore, as described above, when the powder precursor 111 is subjected to crystal growth in a state where a temperature gradient along the X direction is generated, crystals with orientation along the X direction can be formed.

[0148] The above organic light-emitting material contains an oxazole derivative, and the above triplet sensitizer contains a coumarin derivative. By combining such a triplet sensitizer and an organic light-emitting material and using them in the manufacturing method of the present embodiment, it is easy to manufacture a high-quality light-upconversion organic film with high light upconversion efficiency.

[0149] In addition, the organic film manufacturing apparatus 10 of the present embodiment includes a precursor holding portion 11, a pair of clamping portions 12A and 12B, a pressing mechanism 14, and a first heating mechanism 13.

[0150] The precursor holding portion 11 has a holding space 114 with a predetermined height, and holds the powder precursor 111 containing the triplet sensitizer and the organic light-emitting material in the holding space 114.

[0151] A pair of clamping portions 12A and 12B (the first clamping portion 12A and the second clamping portion 12B) clamp the precursor holding portion 11 in the height direction (Z direction).

[0152] The pressing mechanism 14 presses the pair of clamping portions 12A and 12B in a direction approaching each other.

[0153] The first heating mechanism 13 heats the temperature of the -X side end portion of the powder precursor 111, i.e., the first temperature, and the temperature of the +X side end portion, i.e., the second temperature, to different temperatures, so as to generate a temperature gradient along the X direction. Then, after heating the powder precursor 111 to the melting point T of the organic light-emitting material melt(PPO) and above, while maintaining the temperature difference ΔT' between the first temperature and the second temperature, the first temperature and the second temperature are gradually decreased to below the freezing point T solid(PPO) .

[0154] With such an organic film manufacturing apparatus 10, a light-upconversion organic film can be manufactured by the manufacturing method described above. That is, the first heating mechanism 13 can sequentially cool the +X side of the molten powder precursor 111 to below the freezing point T solid(PPO) , and a light-upconversion organic film with crystal growth along the X direction can be manufactured. Thus, a light-upconversion organic film with high light upconversion efficiency and good quality can be manufactured.

[0155] In addition, since no organic solvent needs to be used, the environmental burden in the manufacture of the light-upconversion organic film can be reduced.

[0156] In the organic film manufacturing apparatus 10 of the present embodiment, the first heating mechanism 13 includes a first heating unit 131 provided at the -X side end of the pair of clamping parts 12A and 12B, a second heating unit 132 provided at the +X side end, and a cooling unit 133 connected to the +X side end.

[0157] By adjusting the heating temperatures of the first heating unit 131 and the second heating unit 132 respectively, a temperature gradient along the X direction can be generated in the pair of clamping parts 12A and 12B. On the other hand, when only the first heating unit 131 and the second heating unit 132 are used, since the heat on the -X side of the high-temperature side is excessively transferred to the +X side of the low-temperature side, it becomes difficult to appropriately adjust the temperature difference ΔT. In contrast, by providing the cooling unit 133, the temperature difference ΔT (and the temperature difference ΔT´) can be appropriately adjusted.

[0158] The first heating unit 131 is composed of a first rod heater 131A embedded in the -X side end of the first clamping part 12A and a first rod heater 131B embedded in the -X side end of the second clamping part 12B. Similarly, the second heating unit 132 is composed of a second rod heater 132A embedded in the +X side end of the first clamping part 12A and a second rod heater 132B embedded in the +X side end of the second clamping part 12B.

[0159] Thereby, both the first clamping part 12A and the second clamping part 12B can be maintained at the same temperature gradient. That is, it is possible to suppress the occurrence of a temperature difference in the Z direction of the powder precursor 111, and a temperature gradient only along the X direction can be generated.

[0160] In the present embodiment, the precursor holding part 11 is a pair of glass substrates 112A and 112B separated in the Z direction with a spacer 113 therebetween, and a holding space 114 is formed by the gap between the pair of glass substrates 112A and 112B. And, the precursor holding part 11 and an O-ring 122 for absorbing stress in the Z direction are provided between the pair of clamping parts 12A and 12B.

[0161] By using the gap between the pair of glass substrates 112A and 112B with the spacer 113 therebetween, the powder precursor 111 can be accommodated in the holding space 114 with a uniform thickness in the Z direction, and a light up-conversion organic film with a uniform thickness can be manufactured.

[0162] In the present embodiment, as the decompression mechanism 15, there is a vacuum chamber 151. The precursor holding part 11, the pair of clamping parts 12A and 12B, the pressing mechanism 14, and the first heating mechanism 13 are accommodated in the vacuum chamber 151, and it is set to a decompressed state by a vacuum pump 152.

[0163] Accordingly, air can be discharged when the powder precursor 111 is pressed by the pressing mechanism 14. Therefore, a light up-conversion organic film with suppressed air bubble mixing can be manufactured.

[0164] In the present embodiment, there is also provided a heat insulating material 135 that clamps the pair of clamping portions 12A and 12B in the Z direction.

[0165] Accordingly, external outflow of heat from the pair of clamping portions 12A and 12B can be suppressed, and it is easy to maintain the temperature difference ΔT between the -X side end portion and the +X side end portion of the pair of clamping portions 12A and 12B constant. In particular, the heat insulating material 135 is provided so as to cover the position overlapping with the precursor holding portion 11 in the Z direction. Accordingly, the temperature gradient of the precursor holding portion 11 along the X direction can be appropriately maintained.

[0166] [Second Embodiment]

[0167] Next, the second embodiment will be described.

[0168] In the above first embodiment, the precursor holding portion 11 is clamped by the pair of clamping portions 12A and 12B that have a temperature gradient generated by heating by the first heating mechanism 13, and the heating temperature of the first heating mechanism 13 is decreased at a constant speed. In contrast, in the second embodiment, it is different from the above first embodiment in that the precursor holding portion 11 is moved relative to a heating region having a temperature gradient.

[0169] Figure 7 It is a schematic diagram showing a general configuration of the organic film manufacturing apparatus 20 in the second embodiment.

[0170] The organic film manufacturing apparatus 20 of the present embodiment includes a precursor holding portion 21, a pair of guide plates (a first guide plate 22A and a second guide plate 22B), a second heating mechanism 23, a moving mechanism 24, a decompression mechanism 25, and a control regulator 26.

[0171] The precursor holding portion 21 is the same as the precursor holding portion 11 of the first embodiment, and a holding space 114 is formed by a pair of glass substrates 112A and 112B and a spacer 113, and the powder precursor 111 is held in the holding space 114. It should be noted that, in the first embodiment, it is an intermittent process type organic film manufacturing apparatus 10 for manufacturing one light up-conversion organic film. On the other hand, in the second embodiment, it is a continuous process type organic film manufacturing apparatus 20 that can continuously manufacture a light up-conversion organic film with the X direction as the length direction. Therefore, it can be formed to be longer in the X direction than the precursor holding portion 11 of the first embodiment.

[0172] The first guide plate 22A and the second guide plate 22B function as a pair of guide parts for guiding the movement of the precursor holding part 21 in the X direction. In the present embodiment, the first guide plate 22A and the second guide plate 22B are separated by a constant distance in the Z direction, and their opposing surfaces are parallel to the XY plane.

[0173] The precursor holding part 21 is clamped by the first guide plate 22A and the second guide plate 22B in the Z direction, so that the precursor holding part 21 is pressed in the Z direction. That is, in the present embodiment, the pair of first guide plates 22A and second guide plates 22B function as pressing parts.

[0174] The second heating mechanism 23 generates a temperature gradient along the X direction in the first guide plate 22A and the second guide plate 22B. For example, the second heating mechanism 23 is a plurality of rod heaters 231 buried at constant intervals along the X direction in the first guide plate 22A and the second guide plate 22B, and the driving of each is adjusted individually. Thus, by individually adjusting the temperature of each rod heater 231, a temperature gradient is generated in the pair of guide plates 22A and 22B along the X direction.

[0175] More specifically, the second heating mechanism 23 generates a temperature gradient of a low temperature region, a high temperature region, and a low temperature region along the X direction of the pair of guide plates 22A and 22B. The temperature of the low temperature region is lower than the freezing point of the organic light-emitting material. The temperature of the high temperature region is above the melting point of the organic light-emitting material. At this time, the temperature is adjusted so that the opposing positions of the first guide plate 22A and the second guide plate 22B are at the same temperature.

[0176] Here, the temperature gradient of the part changing from the high temperature region to the low temperature region is greater than that of the part changing from the low temperature region to the high temperature region when moving from the -X side toward the +X side. In addition, in the high temperature region, the temperature above the melting point of the organic light-emitting material is maintained for a certain distance along the X direction. Thus, when the precursor holding part 11 is moved at a constant speed from the +X side toward the -X side, the powder precursor 111 at any position is heated at a specified heating rate, maintained at a temperature above the melting point of the organic light-emitting material for a constant time, and then cooled at a specified cooling rate. Here, the cooling rate of the powder precursor 111 conveyed along the X direction is set according to the temperature difference ΔT´ between the -X side end and the +X side end of the powder precursor 111 moving from the high temperature region to the low temperature region. For example, when ΔT´ = 10 °C, it is set to -3 °C / min.

[0177] It should be noted that in the above example, the precursor holding part 21 is relatively moved toward the -X side at a constant speed, and the powder precursor 111 is heated in sequence at a preset heating rate (for example, 5 °C / min), and the powder precursor 111 is cooled at a preset cooling rate (for example, -3 °C / min). Therefore, the temperature of each part is adjusted so that the temperature gradient of the part changing from the low-temperature region to the high-temperature region is larger than that of the part changing from the high-temperature region to the low-temperature region when moving from the -X side toward the +X side.

[0178] On the other hand, it is also possible to make the temperature gradients of the part changing from the low-temperature region to the high-temperature region and the part changing from the high-temperature region to the low-temperature region the same when moving from the -X side toward the +X side. At this time, it is only necessary to appropriately adjust the moving speed of the precursor holding part 21 starting from the +X side and perform heating based on the preset heating rate and cooling based on the preset cooling rate.

[0179] After the moving mechanism 24 presses the precursor holding part 21 holding the powder precursor 111 between a pair of guide plates 22A and 22B, the precursor holding part 21 is moved toward the -X side.

[0180] It should be noted that in the present embodiment, although the moving mechanism 24 is shown as Figure 7 a pair of guide plates 22A and 22B are fixed and the precursor holding part 21 is moved toward the -X side, it is not limited thereto. Figure 8 It is a schematic diagram showing a general configuration of an organic film manufacturing apparatus 20A according to a modified example of the second embodiment.

[0181] For example, as Figure 8 shown, it can be configured such that a pair of guide plates 22A and 22B are moved toward the +X side by using, for example, a driving roller or the like.

[0182] Similar to the first embodiment, the pressure reducing mechanism 25 is composed of, for example, a vacuum chamber and a vacuum pump (not shown), and maintains the installation environment of the precursor holding part 21, a pair of guide plates 22A and 22B, the second heating mechanism 23, and the moving mechanism 24 in a reduced-pressure state.

[0183] The adjustment controller 26 adjusts the second heating mechanism 23, the moving mechanism 24, and the pressure reducing mechanism 25. Although not shown, it includes a heating drive circuit for separately adjusting each rod heater 231, a moving adjustment circuit for adjusting the moving mechanism 24, a pressure reducing adjustment circuit for adjusting the pressure reducing mechanism 25, and a processor.

[0184] The processor appropriately outputs adjustment signals to these drive circuits. Thereby, the second heating mechanism 23 is adjusted to generate a temperature gradient in a pair of guide plates 22A and 22B, and the precursor holding part 11 is relatively moved with respect to the pair of guide plates 22A and 22B.

[0185] Figure 9 It is a flowchart showing a method for manufacturing an upconversion organic film according to this embodiment.

[0186] In this embodiment, step S1 is carried out in the same manner as in the first embodiment, preparing the powder precursor 111 and holding it in the precursor holding part 21. In addition, the precursor holding part 21 is fixed relative to the moving mechanism 24.

[0187] Next, the processor adjusts the second heating mechanism 23 to heat the pair of guide plates 22A, 22B to generate the temperature gradient described above (step S12).

[0188] Next, the processor adjusts the moving mechanism 24 to press the precursor holding part 21 between the pair of guide plates 22A, 22B and move it toward the X side (step S13).

[0189] Thereby, the powder precursor 111 is pressed by the pair of guide plates 22A, 22B in the Z direction. In addition, the powder precursor 111 held in the precursor holding part 21 moves toward the -X side. By moving from the low-temperature region on the +X side to the high-temperature region, the powder precursor 111 is heated at a prescribed heating rate and heated to the melting point T melt(PPO) above and melted. After that, by moving the powder precursor 111 from the high-temperature region toward the low-temperature region, cooling is sequentially performed from the -X side end of the powder precursor 111 at a prescribed cooling rate. Thus, in the same manner as in the first embodiment, the molten powder precursor 111 is sequentially crystallized along the X direction which is the direction of the temperature gradient.

[0190] Thereby, an upconversion organic film having a crystal orientation along the X direction is manufactured.

[0191] In this embodiment, by continuously moving the precursor holding part 21 toward the -X side by using the moving mechanism 24, an upconversion organic film can be continuously manufactured.

[0192] [Function and effect of this embodiment]

[0193] In the method for manufacturing an upconversion organic film according to this embodiment, in step S1, the powder precursor 111 containing a triplet sensitizer and an organic light-emitting material is held in the holding space 114 of the precursor holding part 21. In step S12, the guide plates 22A, 22B are heated to generate a temperature gradient along the X direction. Then, in step S13, the precursor holding part 21 is relatively moved in the X direction with respect to the pair of guide plates 22A, 22B as heating members.

[0194] Thus, through step S13, the powder precursor 111 transported to the high-temperature region melts, and the molten powder precursor 111 further moves toward the -X side. Thus, it is gradually cooled from the -X side end to a temperature below the freezing point T solid(PPO) . Therefore, similarly to the first embodiment, it is possible to manufacture a high-quality light-upconversion organic film with high light-upconversion efficiency that has undergone crystal growth along the X direction.

[0195] In addition, in this embodiment, it is not necessary to use an organic solvent, and the environmental burden in the manufacture of the light-upconversion organic film can be reduced.

[0196] The organic film manufacturing apparatus 20 of this embodiment includes a precursor holding portion 21, a pair of guide plates 22A, 22B (guide portions), a second heating mechanism 23, and a moving mechanism 24.

[0197] The precursor holding portion 21, similarly to the first embodiment, has a holding space 114 for holding the powder precursor 111 containing the triplet sensitizer and the organic light-emitting material.

[0198] The pair of guide plates 22A, 22B press and clamp the precursor holding portion 21 in the Z direction and guide the precursor holding portion 21 so as to be movable along the X direction.

[0199] The second heating mechanism 23 heats the pair of guide plates 22A, 22B so as to generate a temperature gradient along the X direction from a high-temperature region above the melting point of the organic light-emitting material to a low-temperature region below the freezing point of the organic light-emitting material.

[0200] The moving mechanism 24 relatively moves the precursor holding portion 21 with respect to the pair of guide plates 22A, 22B in the X direction.

[0201] With such an organic film manufacturing apparatus 20, it is possible to manufacture a light-upconversion organic film using the manufacturing method described above. That is, the second heating mechanism 23 causes the pair of guide plates 22A, 22B to generate a temperature gradient along the X direction, and the moving mechanism 24 moves the powder precursor 111 held by the precursor holding portion 21 along the X direction. Therefore, it is possible to melt the powder precursor 111 in the high-temperature region and cool the powder precursor 111 from the -X side toward the +X side in sequence to a temperature below the freezing point T solid(PPO) , and it is possible to manufacture a light-upconversion organic film that has undergone crystal growth along the X direction.

[0202] In addition, since it is not necessary to use an organic solvent, the environmental burden in the manufacture of the light-upconversion organic film can be reduced.

[0203] [Third Embodiment]

[0204] Next, the third embodiment will be described.

[0205] Figure 10 This is a schematic diagram showing the general configuration of the organic film manufacturing apparatus 30 in the third embodiment.

[0206] In the above-described second embodiment, a temperature gradient is generated in a pair of guide plates 22A and 22B constituting the guide portion, and between the pair of guide plates 22A and 22B, the precursor holding portion 21 is relatively moved in the -X direction with respect to the pair of guide plates 22A and 22B.

[0207] In contrast, the organic film manufacturing apparatus 30 in the third embodiment includes a precursor holding portion 31, a plurality of roll pairs 32, a roll heating mechanism 33, a decompression mechanism 25, and a control regulator 36.

[0208] The precursor holding portion 31 of the present embodiment includes a pair of glass substrates 112A and 112B, a spacer 113, and a powder precursor 111 held in a holding space 114 formed by the pair of glass substrates 112A and 112B, in the same manner as the precursor holding portion 21 of the second embodiment. In addition, the precursor holding portion 31 of the present embodiment further includes a pair of support plates 31A and 31B that sandwich the pair of glass substrates 112A and 112B in the Z direction. These support plates 31A and 31B are preferably made of a material having good thermal conductivity, such as metal or the like.

[0209] The roll pair 32 is composed of a pair of rolls 321 arranged in the Z direction, and the precursor holding portion 31 is sandwiched by the pair of rolls 321 arranged in the Z direction. By arranging a plurality of roll pairs 32 in the X direction, the precursor holding portion 31 is held in the XY plane. That is, one of the pair of guide portions of the present invention is constituted by the rolls 321 on the +Z side of the plurality of roll pairs 32, and the other of the pair of guide portions of the present invention is constituted by the rolls 321 on the -Z side of the plurality of roll pairs 32. Each roll 321 has a rotation axis parallel to the Y direction orthogonal to the X direction and the Z direction, and is rotationally driven about the axis by a drive source such as an electric motor. By the rotational drive of the roll 321, the precursor holding portion 31 held in the XY plane is conveyed to the -X side. That is, these roll pairs 32 also function as the moving mechanism of the present invention.

[0210] The roll heating mechanisms 33 independently heat the respective roll pairs 32. That is, the roll heating mechanism 33 functions as the second heating mechanism of the present invention. It should be noted that the pair of rolls 321 arranged in the Z direction constituting one roll pair 32 have the same temperature. Examples of the configuration for heating each roll 321 include a configuration in which a heater is provided on the rotation axis of the roll 321.

[0211] Here, in the present embodiment, the roll heating mechanism 33 heats the roll pair 32 disposed at the -X side end to a temperature lower than the freezing point T of the organic light-emitting materialsolid(PPO) temperature. Further, the roller heating mechanism 33 causes the temperatures of a predetermined number of roller pairs 32 arranged from the roller pair 32 at the -X side end toward the +X side to increase successively toward the +X side, and at least makes the temperature of the Mth (the third in the Figure 10 example) roller pair 32 be the melting point T of the organic light-emitting material melt(PPO) or higher temperature. The temperatures of a predetermined number of roller pairs 32 arranged further toward the +X side from the Mth roller pair 32 decrease successively toward the +X side, and the temperature of the Nth (the fifth in the Figure 10 example) roller pair 32 is set to be lower than the solidification point T of the organic light-emitting material solid(PPO) temperature. It should be noted that, in Figure 10 , for the sake of simplifying the drawing, an example in which there are 5 roller pairs 32 and 3 roller pairs 32 are at high temperature is shown. Actually, more roller pairs 32 are arranged to more finely adjust the temperatures of the respective roller pairs 32. Thus, similarly to the second embodiment, the precursor holding part 31 can be moved so that the powder precursor 111 is heated at a preset heating rate and cooled at a preset cooling rate.

[0212] By transporting the precursor holding part 31 toward the -X side using such a plurality of roller pairs 32, the heat of the roller pairs 32 is respectively transferred to the support plates 31A and 31B of the precursor holding part 31. Thus, the amount of heat transferred to the pair of support plates 31A and 31B varies depending on the position, and a temperature gradient along the X direction is generated in the precursor holding part 31. That is, among the pair of support plates 31A and 31B, the region corresponding to the Mth roller pair 32 corresponds to the high-temperature region of the second embodiment, and the regions corresponding to the roller pair 32 at the -X side end and the Nth roller pair 32 correspond to the low-temperature regions of the second embodiment. Therefore, in this embodiment, similarly to the second embodiment, by moving the powder precursor 111 to the -X side, the powder precursor 111 at any position in the X direction is adjusted from a temperature lower than the solidification point T solid(PPO) to a temperature equal to or higher than the melting point T of the organic light-emitting material at a specified heating rate and melted, and is cooled at a specified cooling rate to a temperature lower than the solidification point T melt(PPO) . Thus, the powder precursor 111 is cooled at the above-mentioned cooling rate in a state having a temperature gradient along the X direction, and thereby crystal growth occurs along the X direction to manufacture the light up-conversion organic film. solid(PPO) The pressure reducing mechanism 25, similarly to the second embodiment, is composed of, for example, a vacuum chamber and a vacuum pump (not shown), and maintains the installation environment of the precursor holding part 31, the plurality of roller pairs 32, and the roller heating mechanism 33 in a reduced-pressure state.

[0213] The pressure reducing mechanism 25, similarly to the second embodiment, is composed of, for example, a vacuum chamber and a vacuum pump (omitted from the drawing), and maintains the installation environment of the precursor holding part 31, the plurality of roller pairs 32, and the roller heating mechanism 33 in a reduced-pressure state.

[0214] The adjustment controller 36 adjusts the roller pair 32, the roller heating mechanism 33, and the pressure reducing mechanism 25. Although not shown in the figure, the adjustment controller 36 includes a heating drive circuit that individually adjusts the roller heating mechanisms 33 of the respective roller pairs 32, a rotation adjustment circuit that rotationally drives the pair of rollers 321 of the roller pair 32, a pressure reduction adjustment circuit that adjusts the pressure reducing mechanism 25, and a processor.

[0215] The processor appropriately outputs adjustment signals to these drive circuits. Thereby, the roller heating mechanism 33 is adjusted to generate a temperature gradient in the precursor holding portion 31 conveyed by the roller pair 32, and the precursor holding portion 11 is moved in the X direction.

[0216] It should be noted that in Figure 10 In the example shown, although an example in which the precursor holding portion 31 is conveyed in the X direction by a plurality of roller pairs 32 is shown, it is not limited thereto, and any configuration that relatively moves the precursor holding portion 31 in the X direction is acceptable. For example, it can be configured such that a plurality of roller pairs 32 maintain their intervals and move toward the +X side with respect to the precursor holding portion 31, or it can be configured such that a plurality of roller pairs 32 move toward the X side and the precursor holding portion 31 moves toward the -X side.

[0217] Figure 11 It is a flowchart showing the manufacturing method of the upconversion organic film of the present embodiment.

[0218] In the present embodiment, the upconversion organic film can be manufactured by a method substantially the same as that of the second embodiment.

[0219] First, step S1 is implemented to prepare the powder precursor 111 and hold it in the precursor holding portion 31. It should be noted that in the present embodiment, a pair of glass substrates 112A and 112B are further clamped by a pair of support plates 31A and 31B.

[0220] Next, the processor adjusts the roller heating mechanism 33 to heat the plurality of roller pairs 32 arranged in the X direction independently. That is, as described above, the temperature of each roller pair 32 is independently adjusted so that from the roller pair 32 at the -X side end to the Mth roller pair 32, it gradually becomes higher toward the +X side, and from the Mth to the Nth roller pair, it gradually becomes lower toward the +X side (step S22).

[0221] Next, the processor adjusts the rotation of each roller pair 32 to convey the precursor holding portion 31 from the roller pair 32 at the +X side end toward the -X side (step S23).

[0222] Thus, a pair of rollers 321 arranged in the Z direction press the powder precursor 111 in the Z direction. In addition, the powder precursor 111 held by the precursor holding portion 31 moves toward the -X side. By transporting the precursor holding portion 31 from the roller pair 32 configured as the Nth and at a low temperature to the roller pair 32 configured as the Mth and at a high temperature, the powder precursor 111 is heated at a prescribed heating rate. Then, near the Mth roller pair 32, the powder precursor 111 is heated to the melting point T melt(PPO) and thus melted. After that, by moving the powder precursor 111 from the Mth roller pair 32 toward the -X side, the powder precursor 111 is cooled sequentially from the -X side end portion thereof at a prescribed cooling rate. Thus, similarly to the above-described embodiments, the melted powder precursor 111 crystallizes sequentially along the X direction, which is the direction of the temperature gradient.

[0223] Thus, an upconversion organic film having a crystal orientation along the X direction can be manufactured.

[0224] In the present embodiment, similarly to the second embodiment, by continuously moving the precursor holding portion 31 toward the -X side using a plurality of roller pairs 32, an upconversion organic film can be continuously manufactured.

[0225] [Function and Effect of the Present Embodiment]

[0226] In the method for manufacturing an upconversion organic film of the present embodiment, in step S1, a powder precursor 111 containing a triplet sensitizer and an organic light-emitting material is held in the holding space 114 of the precursor holding portion 31. In step S22, a plurality of roller pairs are heated respectively so as to generate a temperature gradient along the X direction. Then, in step S23, the precursor holding portion 31 is relatively moved in the X direction using a plurality of roller pairs 32 as heating members.

[0227] Thus, in step S23, the powder precursor 111 transported to the heated roller pair 32 (the Mth roller pair) at a high temperature is melted, and the melted powder precursor 111 is further transported toward the -X side, and thus is gradually cooled from the -X side end portion to a temperature lower than the freezing point T solid(PPO) . Therefore, similarly to the above-described first and second embodiments, an upconversion organic film having a high upconversion efficiency with crystal growth along the X direction and of good quality can be manufactured.

[0228] In addition, in the present embodiment, an organic solvent is not required, and the environmental burden in the manufacture of the upconversion organic film can be reduced.

[0229] The organic film manufacturing apparatus 30 of the present embodiment includes a precursor holding portion 31, a plurality of roller pairs 32 (guide portions), and a roller heating mechanism 33 (second heating mechanism).

[0230] Similar to the first and second embodiments, the precursor holding unit 31 includes a pair of glass substrates 112A and 112B and spacers 113 that form a holding space 114 for holding the powder precursor 111 containing the triplet sensitizer and the organic light-emitting material, and further includes a pair of support plates 31A and 31B that sandwich the pair of glass substrates 112A and 112B.

[0231] A plurality of roller pairs 32 function as a guiding portion of the present invention, and include rollers 321 that rotate about a rotation axis parallel to the Y direction orthogonal to the Z direction and the X direction. A pair of rollers 321 are paired in the Z direction.

[0232] The roller heating mechanism 33 individually adjusts the temperature of each roller pair 32 arranged in the X direction so that the roller pair 32 with the temperature in the high-temperature region (the Mth roller pair 32) to the roller pair 32 with the temperature in the low-temperature region (the roller pair 32 at the -X side end) are arranged in sequence along the X direction.

[0233] With such an organic film manufacturing apparatus 30, an upconversion organic film can be manufactured by the manufacturing method described above. That is, the temperature of a plurality of roller pairs 32 arranged in the X direction is adjusted by the roller heating mechanism 33 to generate a temperature gradient along the X direction. In addition, by the rotational drive of each roller 321 of the roller pair 32, the precursor holding unit 31 holding the powder precursor 111 is moved in the X direction. Therefore, the powder precursor 111 can be melted at a high temperature, and the powder precursor 111 can be cooled from the -X side to below the freezing point T in sequence toward the +X side. solid(PPO) An upconversion organic film that has undergone crystal growth along the X direction can be manufactured.

[0234] In addition, since it is not necessary to use an organic solvent, the environmental burden in the manufacture of the upconversion organic film can be reduced.

[0235] [Fourth Embodiment]

[0236] This embodiment relates to an upconversion organic film. Upconversion is sometimes referred to as photon upconversion.

[0237] The upconversion organic film of this embodiment contains a triplet sensitizer and an organic light-emitting material, and the organic light-emitting material has ultraviolet light-emitting properties. The upconversion organic film of this embodiment is a film having crystallinity.

[0238] In the light upconversion organic film of the present embodiment, the triplet sensitizer absorbs light and is excited, and triplet excitons are generated through intersystem crossing from the lowest excited singlet state to the lowest excited triplet state. The triplet excitons of the organic light-emitting material generated by triplet-triplet energy transfer from the triplet sensitizer diffuse within the crystal of the organic light-emitting material molecules (triplet exciton diffusion), and collide with each other to cause triplet-triplet annihilation (TTA). As a result of TTA, singlet excitons of the organic light-emitting material molecules are generated. The organic light-emitting material in the light upconversion organic film of the present embodiment can emit light with a shorter wavelength than the light absorbed by the triplet sensitizer (upconversion).

[0239] Figure 12 shows the upconversion mechanism in the light upconversion organic film of the present embodiment. As Figure 12 shown, upon absorption of excitation light (e.g., visible photons), the lowest excited singlet state is excited, and the lowest excited triplet state of the triplet sensitizer is generated through intersystem crossing from this lowest excited singlet state. Triplet energy transfer (TET) to the organic light-emitting material occurs, generating the lowest excited triplet state of the organic light-emitting material. When two organic light-emitting material molecules in the triplet state collide, the lowest excited singlet state of the organic light-emitting material is generated through TTA. Luminescence (e.g., UV photons) is generated from the lowest excited singlet state of the organic light-emitting material at an energy level higher than the lowest excited singlet state of the triplet sensitizer. In Figure 12 , respectively, S represents the ground state of the sensitizer, 1 S ＊ represents the lowest excited singlet state of the sensitizer, 3 S ＊ represents the lowest excited triplet state of the sensitizer, A represents the ground state of the light-emitting material, 1 A ＊ represents the lowest excited singlet state of the light-emitting material, 3 A ＊ represents the lowest excited triplet state of the light-emitting material, Φ ISC represents the intersystem crossing quantum efficiency of the sensitizer from the lowest excited singlet state to the lowest excited triplet state, Φ F(S) represents the luminescence quantum efficiency of the sensitizer emitting light from the lowest excited singlet state, Φ F(A) represents the luminescence quantum efficiency of the light-emitting material emitting light from the lowest excited singlet state.

[0240] In the light upconversion organic film of the present embodiment, the triplet sensitizer is a material that absorbs excitation light to generate excited triplet excitons.

[0241] In the light upconversion organic film of the present embodiment, the organic light-emitting material is preferably a material that emits light having a maximum peak in a wavelength region shorter than the maximum peak wavelength on the longest wavelength side of the absorption spectrum of the triplet sensitizer and having a wavelength region of 400 nm or less (preferably 315 nm or more and 400 nm or less).

[0242] Here, the maximum peak wavelength of the triplet sensitizer is the maximum peak wavelength in the absorption spectrum of the individual triplet sensitizer, and the maximum peak wavelength of the organic light-emitting material is the maximum peak wavelength in the emission spectrum of the individual organic light-emitting material.

[0243] The light upconversion organic film according to the present embodiment can upconvert visible light into ultraviolet light. In this specification, ultraviolet light is light in a wavelength region of 315 nm or more and 400 nm or less.

[0244] In the light upconversion organic film according to the present embodiment, preferably, the triplet sensitizer is contained in a state dispersed in the crystalline film of the organic light-emitting material. By dispersing the triplet sensitizer in the crystalline film of the organic light-emitting material, triplet-triplet energy transfer from the triplet sensitizer to the organic light-emitting material easily occurs.

[0245] In the light upconversion organic film of the present embodiment, the molar ratio of the triplet sensitizer to the organic light-emitting material is preferably 1:1000 to 1:100000, more preferably 1:5000 to 1:80000, and further preferably 1:10000 to 1:50000.

[0246] The molar amount M of the organic light-emitting material in the light upconversion organic film of the present embodiment A relative to the molar amount M of the triplet sensitizer S The ratio M A / M S is preferably 1000 or more and 100000 or less. The molar ratio M A / M S is more preferably 5000 or more, and further preferably 10000 or more. The molar ratio M A / M S is more preferably 80000 or less, and further preferably 50000 or less.

[0247] When the ratio M A / M S is 1000 or more, the upconversion quantum efficiency is easily improved, and the excitation threshold intensity can be decreased.

[0248] When the ratio MA / M S is 100,000 or less, and can prevent the decrease in the upconversion quantum efficiency caused by the following (i) and (ii).

[0249] (i) Excessive triplet sensitizer decreases the lifetime of the lowest excited triplet state.

[0250] (ii) The upconversion luminescence is reabsorbed by the triplet sensitizer itself.

[0251] It should be noted that in this specification, for example, the numerical range expressed as "AA to BB" means the range that includes the numerical value AA described before the "to" in "AA to BB" as the lower limit value and the numerical value BB described after the "to" in "AA to BB" as the upper limit value.

[0252] The upconversion organic film of this embodiment preferably does not contain a high molecular compound. The high molecular compound is, for example, a compound having a molecular weight of 10,000 or more. As the high molecular compound, for example, a polymer can be cited. The triplet sensitizer and the organic light-emitting material are also preferably not high molecular compounds.

[0253] The total content of the triplet sensitizer and the content of the organic light-emitting material in the upconversion organic film of this embodiment is preferably 90% by mass or more, more preferably 95% by mass or more, and further preferably 99% by mass or more.

[0254] The upconversion organic film of this embodiment preferably consists essentially of only two components, namely a triplet sensitizer and an organic light-emitting material.

[0255] In the upconversion organic film according to this embodiment, the content of the organic solvent is preferably 1% by mass or less, more preferably 0.1% by mass or less, and further preferably 0.01% by mass or less. The upconversion organic film according to this embodiment preferably does not contain an organic solvent. Since the organic solvent has volatility, flammability, and biological toxicity, the lower the content of the organic solvent in the film, the more excellent the safety and stability of the upconversion organic film, and the easier it is to be applied to environmentally friendly applications.

[0256] In the upconversion organic film according to this embodiment, the excitation threshold intensity is preferably 50 mW / cm 2 or less, more preferably 45 mW / cm 2 or less, further preferably 30 mW / cm 2 or less, and even more preferably 25 mW / cm 2 or less.

[0257] (Organic light-emitting material)

[0258] In the light up-conversion organic film of the present embodiment, the fluorescence quantum yield of the organic light-emitting material is preferably 40% or more, more preferably 50% or more. By having the fluorescence quantum yield of the organic light-emitting material be 40% or more, it is easy to improve the up-conversion quantum efficiency.

[0259] In the light up-conversion organic film of the present embodiment, it is preferred that the crystal of the organic light-emitting material has uniaxial orientation. As described in the examples below, the uniaxial orientation of the crystal can be confirmed by observation with a polarization microscope. By having the crystal of the organic light-emitting material have uniaxial orientation, triplet-triplet energy transfer from the triplet sensitizer to the organic light-emitting material and triplet-triplet energy transfer between organic light-emitting materials are likely to occur.

[0260] In the light up-conversion organic film of the present embodiment, the melting point of the organic light-emitting material is preferably 120 °C or lower, more preferably 100 °C or lower, and still more preferably 80 °C or lower. By having the melting point of the organic light-emitting material be 120 °C or lower, it is easy to form the light up-conversion organic film in the manufacturing method related to the above embodiment.

[0261] In the light up-conversion organic film of the present embodiment, it is preferred that the organic light-emitting material does not contain metal atoms in the molecule. By using an organic light-emitting material that does not contain metal atoms, it is possible to avoid the generation of environmental pollution caused by metals during the manufacture and disposal of the light up-conversion organic film.

[0262] In the light up-conversion organic film of the present embodiment, the organic light-emitting material preferably contains only hydrogen atoms, carbon atoms, oxygen atoms, and nitrogen atoms in the molecule.

[0263] In the light up-conversion organic film of the present embodiment, it is also preferred that the organic light-emitting material does not contain a condensed ring skeleton having three or more benzene rings in the molecule.

[0264] In the light up-conversion organic film of the present embodiment, preferably, the organic light-emitting material contains at least any one compound selected from the group consisting of oxazole derivatives, thiazole derivatives, furan derivatives, fluorene derivatives, dibenzofuran derivatives, and dibenzothiophene derivatives.

[0265] In the light up-conversion organic film of the present embodiment, the organic light-emitting material preferably contains an oxazole derivative.

[0266] In the light up-conversion organic film of the present embodiment, the organic light-emitting material preferably contains a compound represented by the following general formula (1).

[0267]

Chemical formula 1

[0268]

[0269] In the above general formula (1), R11 , R 12 and R 13 are each independently a hydrogen atom or a substituent.

[0270] In the above general formula (1), R as a substituent 11 , R 12 and R 13 are each independently preferably a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms, or a substituted or unsubstituted heterocyclic group having 5 to 50 ring atoms.

[0271] In the above general formula (1), R 11 and R 12 are each independently preferably a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms, more preferably a substituted or unsubstituted aryl group having 6 to 18 ring carbon atoms, and further preferably a substituted or unsubstituted aryl group having 6 to 14 ring carbon atoms.

[0272] In the above general formula (1), R 13 is preferably a hydrogen atom.

[0273] In the above general formula (1), R 11 and R 12 are preferably the same group as each other.

[0274] Examples of the substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms include: phenyl, 1-naphthyl, 2-naphthyl, 1-anthryl, 2-anthryl, 9-anthryl, 1-phenanthryl, 2-phenanthryl, 3-phenanthryl, 4-phenanthryl, 9-phenanthryl, 1-tetraphenyl, 2-tetraphenyl, 9-tetraphenyl, 1-pyrenyl, 2-pyrenyl, 4-pyrenyl, 2-biphenylyl, 3-biphenylyl, 4-biphenylyl, 4-p-terphenyl-4-yl, 4-p-terphenyl-3-yl, 4-p-terphenyl-2-yl, 4-m-terphenyl-4-yl, 4-m-terphenyl-3-yl, 4-m-terphenyl-2-yl, o-tolyl, m-tolyl, p-tolyl, p-tert-butylphenyl, p-(2-phenylpropyl)phenyl, 3-methyl-2-naphthyl, 4-methyl-1-naphthyl, 4-methyl-1-anthryl, 4'-methylbiphenyl, 4''-tert-butyl-p-terphenyl-4-yl, etc.

[0275] As a substituted or unsubstituted heterocyclic group having 5 to 50 ring-forming atoms, for example, the following can be mentioned: 1-pyrrolyl, 2-pyrrolyl, 3-pyrrolyl, pyrazinyl, 2-pyridyl, 3-pyridyl, 4-pyridyl, 1-indolyl, 2-indolyl, 3-indolyl, 4-indolyl, 5-indolyl, 6-indolyl, 7-indolyl, 1-isoindolyl, 2-isoindolyl, 3-isoindolyl, 4-isoindolyl, 5-isoindolyl, 6-isoindolyl, 7-isoindolyl, 2-furyl, 3-furyl, 2-benzofuryl, 3-benzofuryl, 4-benzofuryl, 5-benzofuryl, 6-benzofuryl, 7-benzofuryl, 1-iso-benzofuryl, 3-iso-benzofuryl, 4-iso-benzofuryl, 5-iso-benzofuryl, 6-iso-benzofuryl, 7-iso-benzofuryl, quinolinyl, 3-quinolinyl, 4-quinolinyl, 5-quinolinyl, 6-quinolinyl, 7-quinolinyl, 8-quinolinyl, 1-isoquinolinyl, 3-isoquinolinyl, 4-isoquinolinyl, 5-isoquinolinyl, 6-isoquinolinyl, 7-isoquinolinyl, 8-isoquinolinyl, 2-quinoxalinyl, 5-quinoxalinyl, 6-quinoxalinyl, 1-carbazolyl, 2-carbazolyl, 3-carbazolyl, 4-carbazolyl, 9-carbazolyl, 1-phenanthridinyl, 2-phenanthridinyl, 3-phenanthridinyl, 4-phenanthridinyl, 6-phenanthridinyl, 7-phenanthridinyl, 8-phenanthridinyl, 9-phenanthridinyl, 10-phenanthridinyl, 1-acridinyl, 2-acridinyl, 3-acridinyl, 4-acridinyl, 9-acridinyl, 1,7-diazaphenanthren-2-yl, 1,7-diazaphenanthren-3-yl, 1,7-diazaphenanthren-4-yl, 1,7-diazaphenanthren-5-yl, 1,7-diazaphenanthren-6-yl, 1,7-diazaphenanthren-8-yl, 1,7-diazaphenanthren-9-yl, 1,7-diazaphenanthren-10-yl, 1,8-diazaphenanthren-2-yl, 1,8-diazaphenanthren-3-yl, 1,8-diazaphenanthren-4-yl, 1,8-diazaphenanthren-5-yl, 1,8-diazaphenanthren-6-yl, 1,8-diazaphenanthren-7-yl, 1,8-diazaphenanthren-9-yl, 1,8-diazaphenanthren-10-yl, 1,9-diazaphenanthren-2-yl, 1,9-diazaphenanthren-3-yl, 1,9-diazaphenanthren-4-yl, 1,9-diazaphenanthren-5-yl, 1,9-diazaphenanthren-6-yl, 1,9-diazaphenanthren-7-yl, 1,9-diazaphenanthren-8-yl, 1,9-diazaphenanthren-10-yl, 1,10-diazaphenanthren-2-yl, 1,10-diazaphenanthren-3-yl, 1,10-diazaphenanthren-4-yl, 1,10-diazaphenanthren-5-yl, 2,9-diazaphenanthren-1-yl, 2,9-diazaphenanthren-3-yl, 2,9-diazaphenanthren-4-yl, 2,9-diazaphenanthren-5-yl, 2,9-diazaphenanthren-6-yl, 2,9-diazaphenanthren-7-yl, 2,9-diazaphenanthren-8-yl, 2,9-diazaphenanthren-10-yl, 2,8-diazaphenanthren-1-yl, 2,8-phenanthrolin-3-yl, 2,8-phenanthrolin-4-yl, 2,8-phenanthrolin-5-yl, 2,8-phenanthrolin-6-yl, 2,8-phenanthrolin-7-yl, 2,8-phenanthrolin-9-yl, 2,8-phenanthrolin-10-yl, 2,7-phenanthrolin-1-yl, 2,7-phenanthrolin-3-yl, 2,7-phenanthrolin-4-yl, 2,7-phenanthrolin-5-yl, 2,7-phenanthrolin-6-yl, 2,7-phenanthrolin-8-yl, 2,7-phenanthrolin-9-yl, 2,7-phenanthrolin-10-yl, 1-phenazinyl, 2-phenazinyl, 1-phenothiazinyl, 2-phenothiazinyl, 3-phenothiazinyl, 4-phenothiazinyl, 10-phenothiazinyl, 1-phenoxazinyl, 2-phenoxazinyl, 3-phenoxazinyl, 4-phenoxazinyl, 10-phenoxazinyl, 2-oxazolyl, 4-oxazolyl, 5-oxazolyl, 2-oxadiazolyl, 5-oxadiazolyl, 3-furazanyl, 2-thienyl, 3-thienyl, 2-methylpyrrol-1-yl, 2-methylpyrrol-3-yl, 2-methylpyrrol-4-yl, 2-methylpyrrol-5-yl, 3-methylpyrrol-1-yl, 3-methylpyrrol-2-yl, 3-methylpyrrol-4-yl, 3-methylpyrrol-5-yl, 2-tert-butylpyrrol-4-yl, 3-(2-phenylpropyl)pyrrol-1-yl, 2-methyl-1-indolyl, 4-methyl-1-indolyl, 2-methyl-3-indolyl, 4-methyl-3-indolyl, 2-tert-butyl-1-indolyl, 4-tert-butyl-1-indolyl, 2-tert-butyl-3-indolyl, and 4-tert-butyl-3-indolyl, etc.,

[0276] As a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, for example, the following can be mentioned: methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, hydroxymethyl, 1-hydroxyethyl, 2-hydroxyethyl, 2-hydroxyisobutyl, 1,2-dihydroxyethyl, 1,3-dihydroxyisopropyl, 2,3-dihydroxytert-butyl, 1,2,3-trihydroxypropyl, chloromethyl, 1-chloroethyl, 2-chloroethyl, 2-chloroisobutyl, 1,2-dichloroethyl, 1,3-dichloroisopropyl, 2,3-dichlorotert-butyl, 1,2,3-trichloropropyl, bromomethyl, 1-bromoethyl, 2-bromoethyl, 2-bromoisobutyl, 1,2-dibromoethyl, 1,3-dibromoisopropyl, 2,3-dibromotert-butyl, 1,2,3-tribromopropyl, iodomethyl, 1-iodoethyl, 2-iodoethyl, 2-iodoisobutyl, 1,2-diiodoethyl, 1,3-diiodoisopropyl, 2,3-diiodo-tert-butyl, 1,2,3-triiodopropyl, aminomethyl, 1-aminoethyl, 2-aminoethyl, 2-aminoisobutyl, 1,2-diaminoethyl, 1,3-diaminoisopropyl, 2,3-diaminotert-butyl, 1,2,3-triaminopropyl, cyanomethyl, 1-cyanoethyl, 2-cyanoethyl, 2-cyanisobutyl, 1,2-dicyanoethyl, 1,3-dicyanoisopropyl, 2,3-dicyanotert-butyl, 1,2,3-tricyanopropyl, nitromethyl, 1-nitroethyl, 2-nitroethyl, 2-nitroisobutyl, 1,2-dinitroethyl, 1,3-dinitroisopropyl, 2,3-dinitrotert-butyl, and 1,2,3-trinitropropyl, etc.

[0277] In the light up-conversion organic film of the present embodiment, for example, compounds represented by the following formulas (11) to (13) can be used as the organic light-emitting material. The compounds represented by the following formulas (11) to (13) are relatively easy to obtain.

[0278] [Chemical formula 2]

[0279]

[0280] The melting point of the compound represented by the above formula (11) is 69 °C, and the fluorescence quantum yield Φ F(A) is 79%. The compound represented by the above formula (11) is sometimes abbreviated as PPO.

[0281] The melting point of the compound represented by the above formula (12) is 88 °C, and the fluorescence quantum yield Φ F(A) is 46%. The compound represented by the above formula (12) is sometimes abbreviated as PPF.

[0282] The melting point of the compound represented by the above formula (13) is 105 °C, and the fluorescence quantum yield Φ F(A)It is 37%. The compound shown in the above formula (13) is sometimes abbreviated as α-NPO.

[0283] In the upconversion organic film of the present embodiment, the organic light-emitting material is preferably the compound (2,5-diphenyloxazole) shown in the above formula (11).

[0284] (Triplet sensitizer)

[0285] In the upconversion organic film of the present embodiment, the triplet sensitizer is preferably a compound having an absorption maximum wavelength in the wavelength range of sunlight. A compound having an absorption maximum wavelength in the range of 200 nm or more and 1000 nm or less is usually used as the triplet sensitizer. The triplet sensitizer preferably has an absorption maximum wavelength in the range of 400 nm or more and 700 nm or less. By having the absorption maximum wavelength of the triplet sensitizer within such a range, light with a longer wavelength that cannot be utilized in ordinary light-secondary energy conversion elements (elements that convert light into secondary energy) such as solar cells and hydrogen-producing photocatalysts can be converted into light with a shorter wavelength (for example, less than 400 nm) that can be used in ordinary light-secondary energy conversion elements. Therefore, the upconversion organic film of the present embodiment can effectively utilize light in a broad wavelength range contained in sunlight in light-secondary energy conversion elements. In addition, in the upconversion organic film of the present embodiment, in order to effectively utilize light with wavelengths in the blue region, purple region, and ultraviolet region, the triplet sensitizer can be a compound having an absorption maximum wavelength in the range of 250 nm or more and 499 nm or less.

[0286] As a triplet sensitizer, as long as it is a compound having light absorption in the range from the ultraviolet region to the infrared region, even molecular species that have not been called pigments so far can be used. As triplet sensitizers, for example, the following can be cited: acenaphthene derivatives, acetophenone derivatives, anthracene derivatives, diphenylacetylene derivatives, dihydroacridine derivatives, acridine derivatives, acridone derivatives, thioacridone derivatives, angelicin derivatives, anthracene derivatives, anthraquinone derivatives, azafluorene derivatives, azulene derivatives, benzil derivatives, carbazole derivatives, coronene derivatives, tricyclopentadieno[cd,lm,qr]triphenylene (sumanene) derivatives, biphenylene derivatives, fluorene derivatives, perylene derivatives, phenanthrene derivatives, phenanthroline derivatives, phenazine derivatives, benzophenone derivatives, pyrene derivatives, benzoquinone derivatives, biacetyl derivatives, bianthracene derivatives, fullerene derivatives, graphene derivatives, carotene derivatives, chlorophyll derivatives, chrysene derivatives, cinnoline derivatives, coumarin derivatives, curcumin derivatives, dansamide derivatives, flavone derivatives, fluorenone derivatives, fluorescein derivatives, helicene derivatives, indene derivatives, lumichrome derivatives, lumiflavin derivatives, oxadiazole derivatives, diindeno[1,2,3-cd:1',2',3'-lm]pyrene derivatives, phenol derivatives, phenothiazine derivatives, phenoxazine derivatives, phthalazine derivatives, phthalocyanine derivatives, picene derivatives, porphyrin derivatives, porphycene derivatives, hemiporphycene derivatives, subphthalocyanine derivatives, psoralen derivatives, angelicin derivatives, purine derivatives, pyrene derivatives, pyrromethene derivatives, pyridyl ketone derivatives, phenyl ketone derivatives, pyridyl ketone derivatives, thienyl ketone derivatives, furyl ketone derivatives, quinazoline derivatives, quinoline derivatives, quinoxaline derivatives, retinal derivatives, retinol derivatives, rhodamine derivatives, riboflavin derivatives, rubrene derivatives, squarine derivatives, stilbene derivatives, tetracene derivatives, pentacene derivatives, anthraquinone derivatives, tetracenequinone derivatives, pentacenequinone derivatives, carbon disulfide dichloride derivatives, indigo derivatives, thioindigo derivatives, thioxanthene derivatives, thymine derivatives, triphenylene derivatives, triphenylmethane derivatives, triaryl derivatives, tryptophan derivatives, uracil derivatives, xanthene derivatives, ferrocene derivatives, azulene derivatives, biacetyl derivatives, terphenyl derivatives, terthiophene derivatives, oligomeric aryl derivatives, fullerene derivatives, conjugated polyene derivatives, derivatives of fused polycyclic aromatic compounds containing group 14 elements, and derivatives of fused polycyclic heteroaromatic compounds, etc. The triplet sensitizer is not limited to these substances.

[0287] As triplet sensitizers, specifically, the following can be cited: metal porphyrins (metal complexes of porphyrins); metal tetraazaporphyrin (Tetraazaporphyrin) (metal complexes of tetraazaporphyrin (Tetraazaporphyrin)); metal phthalocyanines (metal complexes of phthalocyanines); iodine derivatives of 3,5-dimethylborondipyrromethene; iodine derivatives of 3,5-dimethyl-8-phenylborondipyrromethene and the like, such as borondipyrromethene; Schiff base metal complexes such as Salen metal complexes; metal bipyridine complexes such as rubidium-bipyridine complex and iridium-phenanthroline complex; metal phenanthroline complexes; naphthalene diimides such as N-alkylnaphthalene diimide; acridones such as N-methylacridone and N-butyl-2-chloroacridone; thioxanthones, xanthones, and xanthenes such as 2,4-diethylthioxanthone; acridines such as acridine yellow; coumarins such as coumarin 6 and coumarin 314; biacetyls such as 2,3-butanedione; anthracenes such as 9,10-dibromoanthracene and 9,9'-bianthracene; oligomeric aryls such as bifuran, bithiophene, and bis(benzoxazolyl)thiophene; fused polycyclic heteroaromatic compounds such as chrysene, phenanthrene, or their derivatives, etc. The triplet sensitizer is not limited to these substances.

[0288] In the light up-conversion organic film of the present embodiment, preferably, the triplet sensitizer does not contain a metal atom in the molecule. By using a triplet sensitizer that does not contain a metal atom, it is possible to avoid the occurrence of environmental pollution caused by metals during the manufacture and disposal of the light up-conversion organic film.

[0289] In the light up-conversion organic film of the present embodiment, the triplet sensitizer preferably contains only hydrogen atoms, carbon atoms, oxygen atoms, and nitrogen atoms in the molecule.

[0290] In the light up-conversion organic film of the present embodiment, preferably, the triplet sensitizer contains a coumarin derivative.

[0291] In the light up-conversion organic film of the present embodiment, preferably, the triplet sensitizer is a coumarin derivative and the organic light-emitting material is an oxazole derivative. By combining such a triplet sensitizer and an organic light-emitting material, the overlap integral of the emission spectrum of the triplet sensitizer and the absorption spectrum of the organic light-emitting material increases. As a result, triplet-triplet energy transfer from the triplet sensitizer to the organic light-emitting material easily occurs.

[0292] In the light up-conversion organic film of the present embodiment, preferably, the triplet sensitizer contains a compound having at least one skeleton represented by the following general formula (CMR3) in the molecule.

[0293]

Chemical formula 3

[0294]

[0295] In the above general formula (CMR3), R 31 ~R 36 are each independently a hydrogen atom or a substituent. One or more groups composed of two or more adjacent ones among R 31 ~R 36 are bonded to each other to form a substituted or unsubstituted monocyclic ring, or are bonded to each other to form a substituted or unsubstituted fused ring, or are not bonded to each other. In the above general formula (CMR3), it is preferred that at least one of R 31 ~R 36 is a substituent, and more preferably at least one of R 31 , R 32 and R 35 is a substituent. For example, when R 35 is an electron-donating group, strong light absorption and luminescence are likely to be exhibited. In addition, when at least any one of R 31 and R 32 is a substituent, it is easy to increase the absorption wavelength and the emission wavelength. When at least any one of R 31 and R 32 is an electron-withdrawing group, the luminescence brightness is likely to be increased. In the above general formula (CMR3), as the substituent R 31 ~R 36 are each independently preferably a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms, a substituted or unsubstituted heterocyclic group having 5 to 50 ring atoms, a group represented by -N(R 37 )(R 38 ), a group represented by -C(=O)-OR 39 , a group represented by -S(=O)2-R 40 , or a cyano group. R 37 ~R 40 are each independently a hydrogen atom or a substituent. As the substituent R 37 ~R 40 are each independently preferably a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms, or a substituted or unsubstituted heterocyclic group having 5 to 50 ring atoms. In the above general formula (CMR3), as the substituted or unsubstituted heterocyclic group having 5 to 50 ring atoms of R 31 ~R 40 is also preferably, for example, a substituted or unsubstituted benzimidazolyl group or a substituted or unsubstituted benzothiazolyl group.

[0296] In the light up-conversion organic film of the present embodiment, the triplet sensitizer preferably contains a compound having at least 2 skeletons represented by the above general formula (CMR3) in the molecule. When the triplet sensitizer has at least 2 skeletons represented by the general formula (CMR3) in the molecule, R 31 ~R 36 At least any one of them is a single bond bonded to another skeleton represented by the general formula (CMR3), or a linking group connecting to another skeleton represented by the general formula (CMR3).

[0297] In the light up-conversion organic film of the present embodiment, the triplet sensitizer preferably contains a compound represented by the following general formula (CMR31).

[0298]

Chemical formula 4

[0299]

[0300] In the above general formula (CMR31), L3 is a linking group, and R 32 ~R 36 Are each independently the same as R 32 ~R 36 In the above general formula (CMR3), and multiple R 32 Are the same as or different from each other, multiple R 33 Are the same as or different from each other, multiple R 34 Are the same as or different from each other, multiple R 35 Are the same as or different from each other, multiple R 36 Are the same as or different from each other. L3 as the linking group is preferably a group represented by -C(=O)-, a substituted or unsubstituted arylene group having 6 to 50 ring carbon atoms, or a substituted or unsubstituted divalent heterocyclic group having 5 to 50 ring atoms, and more preferably a group represented by -C(=O)-. In addition, L3 as the linking group is also preferably a substituted or unsubstituted phenylene group, a substituted or unsubstituted pyridylene group, or a substituted or unsubstituted thiophenylene group.

[0301] In the light up-conversion organic film of the present embodiment, the compound represented by the above general formula (CMR31) is preferably a compound represented by the following general formula (CMR32).

[0302]

Chemical formula 5

[0303]

[0304] In the above general formula (CMR32), R 32 ~R 36 Are each independently the same as R 32 ~R 36 In the above general formula (CMR31).

[0305] In the light up-conversion organic film of the present embodiment, preferably, the coumarin derivative as the triplet sensitizer has at least one group represented by -N(R 37 )(R 38 ).

[0306] In the light up-conversion organic film of the present embodiment, preferably, the compound represented by the above general formula (CMR31) and the compound represented by the above general formula (CMR32) each have two groups represented by -N(R 37 )(R 38 ), and each of the two coumarin skeletons has one group represented by -N(R 37 )(R 38 ).

[0307] In the light up-conversion organic film of the present embodiment, preferably, R 35 is a group represented by -N(R 37 )(R 38 ). R 37 and R 38 are each independently preferably a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, more preferably a substituted or unsubstituted alkyl group having 1 to 18 carbon atoms, and still more preferably an alkyl group having 1 to 6 carbon atoms.

[0308] In the light up-conversion organic film of the present embodiment, for example, the following compounds etc. can be used as the triplet sensitizer.

[0309]

Chemical formula 6

[0310]

[0311] In the light up-conversion organic film of the present embodiment, the triplet sensitizer is preferably the above compound (CBDAC). CBDAC is the abbreviation of 3,3’-carbonylbis(7-diethylaminocoumarin).

[0312] In the light up-conversion organic film of the present embodiment, the triplet sensitizer can be an organometallic complex. "Organometallic complex" includes both organometallic compounds having a metal-carbon bond and metal complexes having a coordination bond. The metal complex having a coordination bond contains a metal and a ligand coordinated thereto.

[0313] When the triplet sensitizer is an organometallic complex, light energy can easily move to the organic light-emitting material. The metal atom constituting the organometallic complex as the triplet sensitizer is not particularly limited, and is, for example, at least any one metal atom selected from Li, Mg, Al, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ru, Pd, Ag, Re, Os, Ir, Pt, and Pb. The metal atom constituting the organometallic complex as the triplet sensitizer is preferably Pt or Pd.

[0314] In the light up-conversion organic film of the present embodiment, when the triplet sensitizer is an organometallic complex, the triplet sensitizer preferably contains a platinum atom, and more preferably is an organometallic complex containing a platinum atom.

[0315] Examples of the ligand in the organometallic complex include porphyrins such as octaethylporphyrin or their substituents; phthalocyanines such as tetra-tert-butylphthalocyanine or their substituents; naphthalocyanines such as tetra-tert-butylnaphthalocyanine or their substituents, and the like.

[0316] Examples of the substituent in the substituent include hydrocarbon groups such as chain hydrocarbon groups such as alkyl groups (such as methyl, ethyl, and tert-butyl), alkenyl groups (such as vinyl and allyl), and alkynyl groups (such as ethynyl and propynyl); hydrocarbon groups having an acid group such as carboxyalkyl groups (such as carboxymethyl and carboxyethyl), and the like.

[0317] Among these, as the ligand in the organometallic complex, porphyrins or their substituents and phthalocyanines or their substituents are preferred, and porphyrins or their substituents are more preferred, and substituents of porphyrins are further preferred.

[0318] Specific examples of the organometallic complex as the triplet sensitizer include metal complexes of porphyrins or their substituents and metal complexes of phthalocyanines or their substituents. Among them, metal complexes of porphyrins or their substituents are preferred.

[0319] The metal atoms contained in metal porphyrins (metal complexes of porphyrins) and metal phthalocyanines (metal complexes of phthalocyanines) are, for example, at least any one metal atom selected from Pt, Pd, Ru, Rh, Ir, Zn, and Cu. Porphyrins and their substituents are sometimes referred to as porphyrins, and phthalocyanines and their substituents are sometimes referred to as phthalocyanines.

[0320] The organometallic complex as a triplet sensitizer is also preferably a metal complex selected from at least any one of a Pt complex having a porphyrin or its substituent as a ligand, a Pt complex having a phthalocyanine or its substituent as a ligand, a Pt complex having a naphthalocyanine or its substituent as a ligand, a Pd complex having a porphyrin or its substituent as a ligand, a Pd complex having a phthalocyanine or its substituent as a ligand, and a Pd complex having a naphthalocyanine or its substituent as a ligand.

[0321] Among the examples of the triplet sensitizer, a triplet sensitizer having an absorption maximum wavelength in the range of 500 nm or more and 700 nm or less and containing a metal in its structure, for example, a compound represented by the following general formula (20) can be cited.

[0322]

Chemical formula 7

[0323]

[0324] (In the above general formula (20), R 201 , R 202 , R 204 , R 205 , R 207 , R 208 , R 210 and R 211 are each independently a hydrogen atom or an optionally substituted substituent containing a hydrophilic functional group, R 201 , R 202 , R 204 , R 205 , R 207 , R 208 , R 210 and R 211 are the same as or different from each other, and two adjacent ones among R 201 , R 202 , R 204 , R 205 , R 207 , R 208 , R 210 and R 211 can bond to each other to form a five-membered or six-membered ring having an optionally substituted substituent including a hydrogen atom, and R 203 , R 206 , R 209 and R 212 are each independently an aryl group having an optionally substituted substituent including a hydrogen atom, and R 203 , R 206 , R 209 and R 212 are the same as or different from each other, and M represents a metal atom.)

[0325] Herein, the "optional substituent including a hydrogen atom" means a hydrogen atom or an optional substituent that does not include a hydrogen atom. Additionally, when there are multiple "optional substituents including a hydrogen atom", the "optional substituents including a hydrogen atom" may bond to each other to form a five-membered or six-membered ring having an optional substituent including a hydrogen atom, or may not bond to each other.

[0326] R in the above general formula (20) 201 、R 202 、R 204 、R 205 、R 207 、R 208 、R 210 and R 211 at least one of which is a hydrophilic functional group. Specific examples of the hydrophilic functional group include: a hydrogen atom, an alkyl group (e.g., an alkyl group having 1 to 12 carbon atoms), an alkenyl group, an alkynyl group, a halogen atom, a hydroxy group, an alkylcarbonyloxy group, an arylcarbonyloxy group, an alkoxycarbonyloxy group, an aryloxycarbonyloxy group, a carboxylate group, an alkylcarbonyl group, an arylcarbonyl group, an alkoxycarbonyl group, an aminocarbonyl group, an alkylaminocarbonyl group, a dialkylaminocarbonyl group, an alkylthiocarbonyl group, an alkoxy group, a phosphate group, a phosphonate group, a phosphinate group, a thiocarboxylate group, a sulfate group, a sulfinate group, a sulfite group, a sulfonate group, a phosphoric acid group, a phosphonic acid group, a phosphinic acid group, a thiocarboxylate group, a sulfuric acid group, a sulfinic acid group, a sulfonic acid group, a cyano group, an amino group (including an alkylamino group, a dialkylamino group, an arylamino group, a diarylamino group, and an alkylarylamino group), an acylamino group (including an alkylcarbonylamino group, an arylcarbonylamino group, a carbamoyl group, and a ureido group), an amidino group, an imino group, a mercapto group, an alkylthio group, an arylthio group, an alkylsulfinyl group, a sulfamoyl group, a sulfonamide group, a nitro group, a trifluoromethyl group, a cyano group, an azide group, a heterocyclic group, an alkylaryl group, an aryl group, or a heteroaryl group. The hydrophilic functional group is not limited to these groups.

[0327] Examples of the substituents of the five-membered or six-membered ring formed by bonding two adjacent ones of R 201 、R 202 、R 204 、R 205 、R 207 、R 208 、R 210 and R 211 in the above general formula (20) to each other include, as examples of R 201 、R 202 、R 204 、R 205 、R 207 、R 208 、R 210 and R 211The substituents exemplified by the examples are not limited to these groups. The above five-membered or six-membered ring may or may not be connected to other substituted or unsubstituted porphyrin rings.

[0328] As R in the above general formula (20) 203 、R 206 、R 209 and R 212 Examples of can be cited as examples of R 201 、R 202 、R 204 、R 205 、R 207 、R 208 、R 210 and R 211 The substituents exemplified by the examples are not limited to these groups.

[0329] The metal atom M in the above general formula (20) is at least one metal atom selected from Pt, Pd, Ru, Rh, Ir, Zn, and Cu, etc.

[0330] As the metal porphyrin compounds represented by the above general formula (20), for example, meso-tetraphenyl-tetraphenylporphyrin palladium (CAS No.: 119654-64-7) and other meso-tetraphenyl-tetraphenylporphyrin metal complexes, octaethylporphyrin palladium (CAS No.: 24804-00-0) and other octaethylporphyrin metal complexes, and meso-tetraphenyl-octamethoxy-tetranaphtho[2,3]porphyrin palladium and other octaethylporphyrin metal complexes described in the literature (Y. Murakami et al., J. Phy., Chem. B, 118 (2014) 14442), etc.

[0331] As metal tetraazaporphyrin compounds, compounds represented by the following general formula (21) can be cited.

[0332] [Chemical Formula 8]

[0333]

[0334] (In the above general formula (21), R 201 、R 202 、R 204 、R 205 、R 207 、R 208 、R 210 、R 211 and M are each the same as R in the above general formula (20) 201 、R 202 、R 204 、R 205 、R207 , R 208 , R 210 , R 211 and M have the same meaning.)

[0335] The triplet sensitizer can also be an organic photosensitizing molecule having a structure that does not contain a metal in its structure. By using a triplet sensitizer that does not contain a metal, it is possible to avoid environmental pollution caused by metals during the manufacture and disposal of the upconversion organic film. As an example of a triplet sensitizer that does not contain a metal, specifically, a compound (boron dipyrromethene type) represented by the following general formula (22), C70, etc. can be cited. These triplet sensitizers can be used alone or in combination of two or more.

[0336] [Chemical formula 9]

[0337]

[0338] (In the above general formula (22), R 221 to R 227 are each independently a hydrogen atom or an optionally substituted substituent containing a hydrophilic functional group, and at least one of R 221 to R 227 is a hydrophilic functional group. Among R 221 to R 227 , at least one pair of adjacent substituents (the pair of R 221 and R 222 , the pair of R 222 and R 223 , the pair of R 225 and R 226 , and the pair of R 226 and R 227 ) can be bonded to each other to form a five-membered or six-membered ring having an optionally substituted substituent including a hydrogen atom. R 228 and R 229 each independently represent a halogen atom, a hydrophilic functional group, a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms, or a substituted or unsubstituted alkoxy group having 1 to 5 carbon atoms.)

[0339] R 221 to R 227At least one of them is a hydrophilic functional group. Specific examples of the hydrophilic functional group include: a hydrogen atom, an alkyl group as an aliphatic hydrocarbon group, an alkenyl group or an alkynyl group, a halogen atom, a hydroxyl group, an alkylcarbonyloxy group, an arylcarbonyloxy group, an alkoxycarbonyloxy group, an aryloxycarbonyloxy group, a carboxylate group, an alkylcarbonyl group, an arylcarbonyl group, an alkoxycarbonyl group, an aminocarbonyl group, an alkylaminocarbonyl group, a dialkylaminocarbonyl group, an alkylthiocarbonyl group, an alkoxy group, a phosphate group, a phosphonate group, a phosphinate group, a thiocarboxylate group, a sulfate group, a sulfinate group, a sulfite group, a sulfonate group, a phosphoric acid group, a phosphonic acid group, a phosphinic acid group, a thiocarboxylic acid group, a sulfuric acid group, a sulfinic acid group, a sulfonic acid group, a cyano group, an amino group (including an alkylamino group, a dialkylamino group, an arylamino group, a diarylamino group and an alkylarylamino group), an acylamino group (including an alkylcarbonylamino group, an arylcarbonylamino group, a carbamoyl group and a ureido group), an amidino group, an imino group, a mercapto group, an alkylthio group, an arylthio group, an alkylsulfinyl group, a sulfamoyl group, a sulfonamide group, a nitro group, a trifluoromethyl group, a cyano group, an azide group, a heterocyclic group, an alkylaryl group, a phenoxy group, an aryl group, a heteroaryl group or a heteroaryloxy group, and are not limited to these groups.

[0340] As substituents (R 221 and R 222 in the above general formula (22) that are adjacent to each other 222 and R 223 in the pair, R 225 and R 226 in the pair, and R 226 and R 227 in the pair), examples of the substituents of the five-membered or six-membered ring formed by bonding at least any one pair of them to each other include the substituents listed as examples of R 221 to R 227 , and are not limited to these groups.

[0341] R 221 , R 223 , R 225 and R 227 in the above general formula (22) can each independently be a hydrogen atom, a halogen atom, a hydrophilic functional group, a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 4 carbon atoms, a substituted or unsubstituted phenyl group, a substituted or unsubstituted phenoxy group, a substituted or unsubstituted thiophenyl group, a substituted or unsubstituted thiophenoxy group, 2-carboxyvinyl represented by the following formula (23) or 2-carboxy-2-cyanovinyl represented by the following formula (24), etc.

[0342] [Chemical Formula 10]

[0343]

[0344] R 222 and R 226Each is independently preferably a hydrogen atom, a halogen atom, a hydrophilic functional group, a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 4 carbon atoms, a substituted or unsubstituted phenyl group, a substituted or unsubstituted phenoxy group, a substituted or unsubstituted thiophenyl group, a substituted or unsubstituted thiophenoxy group, 2-carboxyvinyl represented by the above formula (23), or 2-carboxy-2-cyanovinyl represented by the above formula (24).

[0345] More preferably, R in the above general formula (22) 222 and R 226 are each independently a hydrogen atom, a bromine atom, or an iodine atom, and at least one of R 222 and R 226 is a bromine atom or an iodine atom.

[0346] Even more preferably, R in the above general formula (22) 222 and R 226 are each independently a hydrogen atom or an iodine atom, and at least one of R 222 and R 226 is an iodine atom.

[0347] R in the above general formula (22) 224 is preferably a hydrogen atom, a halogen atom, a hydrophilic functional group, a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 4 carbon atoms, a substituted or unsubstituted phenyl group, a substituted or unsubstituted phenoxy group, a substituted or unsubstituted thiophenyl group, a substituted or unsubstituted thiophenoxy group, 2-carboxyvinyl represented by the above formula (23), or 2-carboxy-2-cyanovinyl represented by the above formula (24).

[0348] R in the above general formula (22) 224 is more preferably a substituted or unsubstituted phenyl group.

[0349] R in the above general formula (22) 224 is even more preferably an unsubstituted phenyl group, an alkyl-substituted phenyl group, or a phenyl group having a hydrophilic functional group.

[0350] R in the above general formula (22) 228 and R 229 are each independently a halogen atom, a hydrophilic functional group, a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms, or a substituted or unsubstituted alkoxy group having 1 to 5 carbon atoms. R in the above general formula (22) 228 and R 229 are preferably a fluorine atom.

[0351] In the compound represented by the above general formula (22), it is further preferred that R 221 to R 227Each independently represents a hydrogen atom, a halogen atom, a hydrophilic functional group, a substituted or unsubstituted aliphatic hydrocarbon group having 1 to 4 carbon atoms, a substituted or unsubstituted phenyl group, a substituted or unsubstituted phenoxy group, a substituted or unsubstituted thiophenyl group, a substituted or unsubstituted thiophenoxy group, 2-carboxyvinyl represented by the above formula (23), or 2-carboxy-2-cyanovinyl represented by the above formula (24).

[0352] The compound represented by the above general formula (22) is more preferably a compound represented by the following general formula (25). With the compound represented by the following general formula (25), a light upconversion material having higher light wavelength conversion efficiency can be achieved.

[0353]

Chemical Formula 11

[0354]

[0355] (In the above general formula (25), R 221 , R 223 , R 225 and R 227 each independently represent a hydrophilic functional group, or a substituted or unsubstituted alkyl group having 1 to 3 carbon atoms, R 222 and R 226 each independently represent a hydrogen atom, a bromine atom, or an iodine atom, at least one of R 222 and R 226 is a bromine atom or an iodine atom, and R 224 represents a substituted or unsubstituted phenyl group.)

[0356] The triplet sensitizer can be a metal porphyrin of the above general formula (20) or a compound of the above general formula (22).

[0357] In the light upconversion organic film of the present embodiment, as a specific example of the triplet sensitizer, for example, the following compounds can also be cited, and the present invention is not limited to the following compounds.

[0358]

Chemical Formula 12

[0359]

[0360] The light upconversion organic film of the present embodiment can also be manufactured by any of the manufacturing methods described in the first, second, and third embodiments. In addition, the light upconversion organic film of the present embodiment can also be manufactured by any of the manufacturing apparatuses described in the first, second, and third embodiments.

[0361] According to the present embodiment, a photoluminescence upconversion organic film can be provided, which can stably upconvert light in the visible light region to light in the ultraviolet light region in the atmosphere and exhibits a high upconversion quantum efficiency at an excitation light intensity lower than the intensity of sunlight irradiated on the earth's surface (for example, an intensity about 0.3 times the intensity of sunlight). In addition, according to an aspect of the present embodiment, a photoluminescence upconversion organic film that exhibits high durability against excitation light and high light irradiation stability can be provided. The photoluminescence upconversion organic film of the present embodiment can function as an ultraviolet ray generating material. Therefore, the photoluminescence upconversion organic film of the present embodiment can greatly expand the usefulness of sunlight on the ground in various fields where ultraviolet rays are required.

[0362] In addition, in the photoluminescence upconversion organic film of the present embodiment, since neither the triplet sensitizer nor the organic light emitting material is an ionic material (ionic liquid), the photoluminescence upconversion organic film of the present embodiment is also chemically stable. In addition, the photoluminescence upconversion organic film of the present embodiment can be used in air and exhibits upconversion luminescence in air.

[0363] The photoluminescence upconversion organic film of the present embodiment can be applied to various uses (for example, photocatalysts, solar cells, and photoorganic synthesis, etc.).

[0364] [Modification Example]

[0365] The present invention is not limited to the above-described embodiments, and modifications, improvements, and configurations obtained by appropriately combining the respective embodiments within the scope capable of achieving the object of the present invention are included in the present invention.

[0366] In the first embodiment, the first heating unit 131 is composed of first rod heaters 131A and 131B, and the second heating unit 132 is composed of second rod heaters 132A and 132B. In contrast, as the first heating mechanism 13, any heating mechanism that generates a temperature gradient in the X direction between the first clamping portion 12A and the second clamping portion 12B can be used, not limited to the rod heater described above. For example, a first electric wire heater can be wound around the -X side end portions of the first clamping portion 12A and the second clamping portion 12B, and a second electric wire heater can be wound around the +X side end portions, and the current values flowing through these electric wire heaters can be adjusted respectively to generate a temperature gradient.

[0367] In the first embodiment, a configuration is illustrated in which temperature sensors 134 made of, for example, thermocouples are provided at the first clamping portion 12A and the second clamping portion 12B. In the second and third embodiments, a configuration in which these temperature sensors are provided may also be adopted. For example, in the second embodiment, it may be configured to provide temperature sensors along the X direction to a pair of guide plates 22A and 22B, and measure the temperature gradient in the guide plates 22A and 22B. At this time, feedback control of the second heating mechanism 23 may be performed based on the measured temperature gradient.

[0368] Similarly, in the third embodiment, it may be configured to provide temperature sensors to each of the plurality of roll pairs 32, respectively. Alternatively, it may also be configured to provide a plurality of temperature sensors along the X direction to a pair of support plates 31A and 31B, respectively.

[0369] In the first embodiment, a configuration is illustrated in which a pair of clamping portions 12A and 12B are clamped by a heat insulating material 135 to suppress heat outflow from the clamping portions 12A and 12B to the fixed table 142 and the movable table 143, but it is not limited thereto. In the first embodiment, since the inside of the vacuum chamber 151 is in a reduced pressure state, heat insulation can be improved by creating a gap between the first clamping portion 12A and the fixed table 142 and between the second clamping portion 12B and the movable table 143.

[0370] In the first to third embodiments, an example is illustrated in which the setting environment of the precursor holding portions 11, 21, and 31 is in a reduced pressure state and the powder precursor 111 is pressed, but it is not limited thereto. For example, the powder precursor 111 may also be pressed under atmospheric pressure. At this time, generation of bubbles may be suppressed by allowing it to stand under atmospheric pressure.

[0371] Examples

[0372] Hereinafter, examples are given to further elaborate on the present invention in detail. The present invention is not limited by any of these examples.

[0373] <Compound>

[0374] The structures of the triplet sensitizers used in the production of the upconversion organic films of Examples 1 to 5 are shown below.

[0375] [Chemical Formula 13]

[0376]

[0377] The structures of the organic light-emitting materials used in the production of the upconversion organic films of Examples 1 to 5 are shown below.

[0378] [Chemical Formula 14]

[0379]

[0380] <Fabrication of the Upconversion Organic Film>

[0381] Using CBDAC as a triplet sensitizer and PPO as an organic light-emitting material, the upconversion organic films of Examples 1 to 5 were fabricated as described below.

[0382] PPO with a purity of 99% manufactured by Sigma-Aldrich and CBDAC with a purity of over 98% manufactured by Tokyo Chemical Industry Co., Ltd. were used. The purchased CBDAC was a methanol solution (4×10 -4 M). This CBDAC methanol solution was filtered using a PTFE membrane filter (manufactured by Merck-LG, product name: SLLGX13NL, pore size: 200 nm) to remove the fine particles that might be present in the CBDAC methanol solution. This methanol solution was used for sample preparation.

[0383] The filtered CBDAC methanol solution (4×10 -4 M) was dropped onto the powder of PPO using a mechanical pipette to form a mixed powder of CBDAC and PPO (molar ratio: 1:30000). It was evacuated in a vacuum chamber connected to a dry vortex vacuum pump for 15 minutes to remove methanol. Finally, this mixture was finely pulverized using a quartz mortar to obtain a uniform mixture of PPO and CBDAC.

[0384] The mixed powder of CBDAC and PPO (mass: approximately 32 mg, CBDAC:PPO = 1:30000 (molar ratio)) was added to the inside of a SUS spacer (thickness: 200 μm, inner diameter 8 mm), and was clamped using two circular glass substrates (the glass substrates manufactured by Corning Inc. (product name: EAGLE XG (registered trademark), diameter: 12 mm, thickness: 0.7 mm) were cut into circular shapes by Matsunami Glass Industry Co., Ltd.). It should be noted that during the fabrication of the upconversion organic film, aluminum thin films (thickness: 50 nm) were vapor-deposited only on one side of the two glass substrates, and the mixed powder was clamped using the side of the glass substrate without aluminum vapor deposition. In addition, in the sample fabrication for the optical property measurement described later, one of the glass substrates with the organic film after the fabrication of the upconversion organic film and the glass substrate without aluminum vapor deposition were used. In addition, in the sample fabrication for the optical microscope observation using transmitted illumination from the bottom described later, two glass substrates without aluminum vapor deposition were used. By performing such operations, a precursor holding part was prepared, and the upconversion organic film was fabricated according to the [Method for Manufacturing Upconversion Organic Film] described in the first embodiment.

[0385] The light upconversion organic films of Examples 1 to 5 are each produced by adjusting the temperature difference ΔT at both ends of a pair of clamping parts 12A, 12B, which is adjusted to less than 1.3°C in Example 1, 10°C in Example 2, 20°C in Example 3, 25°C in Example 4, and 30°C in Example 5.

[0386] exist Figure 13A , Figure 13B , Figure 13C , Figure 13D and Figure 13E In, with Figure 5 Likewise shown is the time-dependent temperature curve recorded using a thermocouple, Figure 13A is a graph showing the temperature change in Example 1 (ΔT<1.3°C), Figure 13B is a graph showing the temperature change in Example 2 (ΔT=10° C.), Figure 13C is a graph showing the temperature change in Example 3 (ΔT=20° C.), Figure 13D is a graph showing the temperature change in Example 4 (ΔT=25° C.), Figure 13E This is a graph showing the temperature change in Example 5 (ΔT = 30°C). Regarding ΔT, due to the presence of a heat sink attached only to one side, the possible minimum ΔT is 0.9±0.4°C, so the ΔT of Example 1 is marked as ΔT < 1.3°C. Figure 13A , Figure 13B , Figure 13C , Figure 13D and Figure 13E In the middle, the solid line and Figure 5 The lines L1 to L5 correspond to the dashed lines. Figure 5 The lines L6 to L8 correspond to T melt(PPO) is the melting temperature of PPO, T solid(PPO) In Examples 1 to 5, the cooling rate was set to -3°C / min.

[0387] The light up-conversion organic films produced in Examples 1 to 5 are believed to contain no organic solvent due to vacuum exhaust during the production of the mixed powder and the light up-conversion organic films. Even if organic solvent is contained, it is believed to be in a very small amount below the detection limit.

[0388] <Evaluation of physical properties, etc.>

[0389] (Optical microscope observation)

[0390] For the upconversion organic films of Examples 1 to 5, optical microscope observations were performed respectively. The optical microscope observations were carried out using a polarization microscope with transmitted illumination (microscope manufactured by Olympus Corporation: product name "BX-53"). The observations based on the polarization microscope were carried out using an orthogonal Nicol configuration.

[0391] In Figure 14 , for the upconversion organic films of Examples 1 to 5, three kinds of photos are shown respectively. In Figure 14 , on the upper part, a stereomicroscope image obtained by photographing the obtained upconversion organic film using transmitted illumination is shown. In the middle and lower parts, magnified microscope images of the upconversion organic film taken using transmitted illumination are shown. The middle part is a normal microscope image, and the lower part is a polarization microscope image. The rightward arrow shown between the photo in the upper part and the photo in the middle part of Figure 14 indicates that the left side is at a high temperature and the right side is at a low temperature temperature gradient.

[0392] According to Figure 14 the images shown, the upconversion organic films of Examples 1 to 5 are mainly composed of single crystal strips grown along the temperature gradient. Therefore, it can be known that the crystallization of the organic light-emitting material (PPO) as the main constituent material of the upconversion organic films of Examples 1 to 5 has uniaxial orientation. The "uniaxial orientation" in this specification means that the crystal domains of the polycrystals constituting the upconversion organic film elongate along the temperature gradient direction to form crystal strips, and it means that the elongation direction generally follows the direction of the temperature gradient, rather than meaning that the elongation direction is strictly consistent with the direction of the temperature gradient. It should be noted that for the organic film made of PPO alone without CBDAC, microscope observations were also carried out in the same manner as above, and as a result, it was found that PPO is a material with uniaxial orientation.

[0393] It should be noted that under the condition of ΔT < 1.3 °C in Example 1, a microcrystalline film with strong light scattering was formed. It is considered that this is due to the sudden solidification of the sample throughout the region. Under the condition of ΔT = 20 °C in Example 3, for the upconversion organic film, single crystal strips mainly growing along the temperature gradient were clearly observed. The width of the single crystal strips observed by the microscope is mainly in the range of 30 μm to 80 μm. Figure 14 The results shown

[0394] As shown in Example 4 and Example 5, when ΔT was increased to 25°C to 30°C, the upconversion organic film crystallized microscopically, and the transparency of the film decreased. This reveals that a ΔT = 20°C as in Example 3 provides a more appropriate cooling rate for the solidification front to achieve crystalline band growth. It should be noted that the upconversion organic film manufactured under the condition of ΔT = 20°C and a cooling rate of -1°C / min is also a microcrystalline film. It can be seen that in order to prevent the disorder of the growth direction of the crystalline band, it is desirable to adjust to an appropriate cooling rate.

[0395] (X-ray diffraction measurement and single crystal X-ray structure analysis)

[0396] Powder X-ray diffraction (PXRD) measurements were performed on the organic light-emitting material used as a raw material and the fabricated upconversion organic film.

[0397] The PXRD measurement was carried out using an X-ray diffractometer (manufactured by Rigaku Corporation, product name: SmartLab), using Cu Kα radiation at 298K. The upconversion organic film was cut into fine powder with a razor blade and annealed at 66°C for 30 minutes in an atmosphere of dry nitrogen. Approximately 50 mg of the annealed fine powder was sandwiched between two Mylar (registered trademark) films and fixed to the measurement stage of the X-ray diffractometer. During the measurement, the measurement stage was rotated at 120 rpm, the scanning step size was set to 0.01°, and the scanning speed was set to 0.5° / min.

[0398] Figure 15 The pattern of powder X-ray diffraction (PXRD) is shown. In Figure 15 the upper part is the PXRD pattern of the obtained PPO powder, the middle part is the PXRD pattern of the upconversion organic film of Example 3 (UC film, ΔT = 20°C), and the lower part is the PXRD pattern of the upconversion organic film of Example 1 (UC film, ΔT < 1.3°C). Figure 15 It is shown that since the upconversion organic film manufactured in the examples shows the same PXRD pattern as the PPO powder, there is no polymorphism.

[0399] Figure 16The crystal structure of PPO obtained by Pawley and Rietveld analysis is shown. Pawley and Rietveld analysis was performed using molecular modeling and simulation software (manufactured by Dassault Systemes Co., Ltd., product name: BIOVIAMaterials Studio 2022 (registered trademark)). Through Pawley and Rietveld analysis, the herringbone packing of PPO was revealed.

[0400] (Photophysical properties)

[0401] Figure 17 The photophysical properties of the upconversion organic film and CBDAC are shown.

[0402] First, Figure 17 The excitation spectrum of the upconversion organic film of Example 3 fabricated at ΔT = 20 °C is shown. The excitation spectrum was obtained by irradiating the upconversion organic film with pulsed light generated by a wavelength-tunable optical parametric oscillator (manufactured by EKSPLA, product name: NT-242, pulse width: approximately 3 ns, repetition frequency: 100 Hz). The excitation spectrum was obtained by plotting the UC emission intensity integrated in the range of 380 nm to 390 nm against the wavelength of the laser that was varied from 410 nm to 488 nm while maintaining the pulse energy at 10 μJ.

[0403] In addition, Figure 17 The absorption spectrum (optical path length = 1 mm) of a methanol solution of CBDAC (concentration: 2×10 -4 M) is also shown.

[0404] By irradiating the upconversion organic films of Examples 1 to 5 with a laser having a wavelength λ = 440 nm, UC emission that peaks in the wavelength range of 390 nm to 393 nm was observed, and fluorescence from CBDAC that peaks in the wavelength range of 480 nm to 490 nm was also observed. The UC emission intensity of the upconversion organic film of Example 3 (ΔT = 20 °C) is stronger than that of the upconversion organic film of Example 1 (ΔT < 1.3 °C) because the crystallinity of the upconversion organic film of Example 3 is high.

[0405] It should be noted that the measurement of the photophysical properties was performed using the combination E10 described in Figure 18A A continuous-wave (CW) laser of 440 nm was oscillated by a laser oscillator E11, and the CW laser was irradiated onto the sample E20 through an optical density filter (ND filter) E12, a beam expander E13, and an aperture E14. The laser beam diameter at the position of the sample E20 is approximately 3 mm, and the beam profile is a top-hat shape. Figure 18BThe enlarged cross-sectional view of sample E20 used for the measurement of photophysical properties is shown. On one surface of the glass substrate E21 of sample E20, a 200-μm-thick upconversion organic film E22 is held, which is surrounded by a spacer E23 with a thickness of 200 μm on its periphery. In addition, on the other surface of the glass substrate E21, an aluminum layer with a thickness of 50 nm as a light reflection layer E24 is provided. The glass substrate E21 of sample E20 is configured to irradiate the upconversion organic film E22 with a laser, and as Figure 18A shown schematically in

[0406] is held at an angle (about 5°) slightly deviated from the perpendicular incident direction of the laser beam. Using two achromatic lenses E15, E16, the photoemission from the upconversion organic film E22 is collected and converged to the entrance slit of a monochromator E17 (manufactured by Princeton Instruments, product name: SP-2300i). The spectrum was recorded using an array-type CCD detector E18 (manufactured by Princeton Instruments, product name: "PIXIS: 100BR") installed at the exit of the monochromator E17. F(S) (See Figure 12 ) for the fluorescence quantum yield Φ of CBDAC in the upconversion organic film doped with a trace amount of CBDAC in the polycrystalline film of PPO. The measurement was carried out using an absolute PL quantum yield measurement device (manufactured by Hamamatsu Photonics K.K., product name: Quantaurus-QY), and it was 5.1%. Therefore, the upconversion quantum efficiency (UC quantum efficiency) Φ UC can be determined by referring to the fluorescence intensity after correcting for the wavelength dependence of the CCD detector and the diffraction grating of the monochromator. Here, the photoemission with a wavelength λ ≤ 425 nm is defined as UC emission. In this definition, 60.1% of the UC photons of the upconversion organic film in Example 3 (ΔT = 20 °C) are ultraviolet (UV) photons with a wavelength λ lower than 400 nm. The upconversion organic film in Example 3 exhibits a higher efficiency than the upconversion organic film in Example 1 (ΔT < 1.3 °C) (maximum, Φ UC = 4.3%, the normalized upconversion luminescence efficiency η UC = 8.6%. η UC ≡ 2Φ UC ).

[0407] (Excitation threshold intensity)

[0408] The upconversion organic film in Example 3 exhibits a lower excitation threshold intensity (I th ) than the upconversion organic film in Example 1 (See Figure 19Aand Figure 19B )。

[0409] Figure 19A and Figure 19B shows Φ UC dependence on the excitation intensity at a wavelength of 440 nm. Figure 19A is a graph of the light up-conversion organic film related to Example 3, Figure 19B is a graph of the light up-conversion organic film related to Example 1. Figure 19A and Figure 19B show that 10 light up-conversion organic films of Example 1 and Example 3 were each prepared and Φ was measured UC and the obtained data. The dot plot represents the measured values, and the solid line represents the theoretical curve fit.

[0410] For the up-conversion threshold intensity (unit: mW / cm 2 ) of the fabricated light up-conversion organic film, the following method was used for measurement. It is known that in TTA-based up-conversion luminescence, in the region of weak excitation light intensity, the up-conversion luminescence intensity is proportional to the square of the excitation light, and in the region of strong excitation light intensity, the up-conversion luminescence intensity is proportional to the first power of the excitation light. The excitation light (wavelength 440 nm) intensity dependence of the up-conversion luminescence intensity was measured, and the excitation light intensity at which the slope of its intensity dependence changes from 2 to 1 on a double logarithmic plot was taken as the up-conversion threshold intensity. The lower the threshold intensity, the more efficient the up-conversion luminescence occurs at low excitation light intensities.

[0411] In Figure 20 , a graph showing the excitation threshold intensity (I th ) of the light up-conversion organic film fabricated under the condition of ΔT = 20 °C and the molar ratio M A / M S is shown. The molar ratio M A / M S is the ratio of the molar amount M A of PPO to the molar amount M S of CBDAC in the light up-conversion organic film. The molar ratio of the triplet sensitizer to the organic luminescent material contained in the light up-conversion organic film is equivalent to the material feeding ratio when preparing the mixed powder, remaining unchanged. As Figure 20 shown, if the molar ratio M A / M S exceeds 10000, there is a tendency for the excitation threshold intensity (I th ) to further decrease. It can be seen that by adjusting the molar ratio M A / M S , the performance of the light up-conversion organic film can be further improved.

[0412] In addition, based on the dependence of the UC emission intensity on the intensity of simulated sunlight (unit: SUN), the excitation threshold intensity (I th ) during sunlight irradiation was measured. The simulated sunlight with an air mass of 1.5 (AM1.5) was generated by a solar simulator (manufactured by Asahi Spectra Co., Ltd., product name: HAL-320). The broadband light generated by the solar simulator was passed through a long-pass filter, and thus, only the light composed of a wavelength range exceeding 413 nm (λ > 413 nm) was irradiated onto the upconversion organic film, and the UC emission intensity was measured. It should be noted that AM1.5 refers to the spectral intensity of sunlight falling on the earth, which is the data of the world standard formulated by the National Renewable Energy Laboratory (NREL) of the U.S. Department of Energy. The unit SUN is the unit representing the intensity of sunlight. The intensity of the simulated sunlight at the sample position was set as follows. First, without using the long-pass filter, a 1 SUN checker (manufactured by Asahi Spectra Co., Ltd., product name: CS-20) was placed at the sample position. By adjusting the output power of the solar simulator, its intensity was set to the intensity of "one day". Then, the long-pass filter was set. After the setting, the long-pass filter exhibited a transmittance of approximately 98% in the wavelength range of light absorption of CBDAC. Therefore, in order to compensate for the decrease in the light intensity at the sample position caused by the setting of this long-pass filter, the output power of the solar simulator was increased to 1.02 times. The light intensity at the sample position in such a state was defined as 1 SUN. The measurement steps and conditions are described in R. Enomoto, M. Hoshi, H. Oyama, H. Agata, S. Kurokawa, H. Kuma, H. Uekusa and Y. Murakami, Mater. Horiz., 2021, 8, 3449.

[0413] Figure 21 A graph showing the sunlight intensity dependence of the upconversion luminescence intensity is shown. Figure 21 Also shown are the dimensionless excitation intensities (Λ) of two samples (sample #1 and #2) of the upconversion organic film related to Example 3 (ΔT = 20°C). It can be seen that the value of the excitation threshold intensity (I th ) of the upconversion organic film of Example 3 is approximately 0.3 SUN. This reveals that the upconversion organic film of Example 3 can be used for sunlight without a concentrating optical system. In Figure 21 , the dot plots represent the measured values and show the theoretical curve fitting. Figure 21 The inset in is the emission spectrum (solid line) of the sample under 1 SUN irradiation and the emission spectrum (dashed line) of the reference sample prepared under the condition of not using a sensitizer.

[0414] In Figure 19A 、 Figure 19B and Figure 21 , first, the excitation light power was increased, and the data indicated by the uncoated mark was obtained. After that, in order to confirm the reproducibility and the stability of the sample, the data indicated by the coated mark was obtained. The theoretical fitting curve and the dimensionless excitation intensity Λ were based on the literature (Y. Murakami and K. Kamada, Phys. Chem. Chem. Phys., 2021, 23, 18268.). The dimensionless excitation intensity Λ = 2 corresponds to the excitation threshold intensity (I th ).

[0415] (Photo-stability)

[0416] Figure 22 A graph showing the photo-stability of the photo-upconversion organic film is presented. Using the apparatus shown in Figure 18A , for the photo-upconversion organic film of Example 3 (ΔT = 20 °C), a laser of 440 nm was continuously irradiated at an intensity of 30 mW / cm 2 in the atmosphere to evaluate the photo-stability. Figure 22 The vertical axis of the graph shows the photo-upconversion luminescence intensity corrected using the time variation of the laser shown in the inset.

[0417] As Figure 22 shown, in this photo-stability test, although a laser of λ = 440 nm was irradiated at an intensity of 30 mW / cm th far exceeding the excitation threshold intensity (I 2 ) in the atmosphere, excellent photo-stability of at least 100 hours or more was exhibited, far exceeding the photo-stability of conventional TTA-UC.

[0418] (Practicality)

[0419] Figure 23 A schematic diagram of an experimental method showing an example of the practicality of the photo-upconversion organic film is presented.

[0420] Prepare two empty small glass vials E27a and E27b (both with an outer diameter of 8 mm and a height of 35 mm). Apply a small amount of ultraviolet curable resin E26 (manufactured by BONDIC Corporation, product name: BD-SKCJ) on the upper surface of the mouth parts of the glass vials E27a and E27b. Place a glass sheet E25 on the ultraviolet curable resin E26 to cover the mouth parts of the glass vials E27a and E27b. Then, place the glass substrate E21 on which the light up-conversion organic film E22 of Example 3 (ΔT = 20 °C) was fabricated at the position corresponding to the mouth part of one glass vial E27a, and place the glass substrate E21 on which the comparative film Ref without a triplet sensitizer was fabricated at the position corresponding to the mouth part of the other glass vial E27b. The comparative film Ref was fabricated in the same manner as in Example 3 except that it does not contain a triplet sensitizer (CBDAC). Irradiate the light E28 of 1 SUN greater than 413 nm (λ > 413 nm) generated by a solar simulator and passed through a long-pass filter from above the light up-conversion organic film E22 and the comparative film Ref for 3 minutes. After the light irradiation, only the ultraviolet curable resin E26 disposed below the light up-conversion organic film E22 is cured, and the glass vial E27a is bonded to the glass sheet E25. On the other hand, the ultraviolet curable resin E26 disposed below the comparative film Ref is not cured, and the glass vial E27b is not bonded to the glass sheet E25. This experimental result shows the practicality of the light up-conversion organic film of the present invention in the atmosphere.

[0421] (Fluorescence quantum yield)

[0422] The fluorescence quantum yield Φ of PPO F(A) is 79%. The quantum yield was measured using an absolute PL quantum yield measurement device (manufactured by Hamamatsu Photonics Corporation, product name: Quantaurus-QY). For PPO, the fluorescence quantum yield Φ was measured in a solid state. F(A) .

[0423] (Melting point and freezing point)

[0424] The melting point (represented by T melt ) and the freezing point (represented by T solid ) of the objects to be measured such as PPO, CBDAC, and the PPO-CBDAC mixture were measured using a differential scanning calorimeter (manufactured by Shimadzu Corporation, product name: DSC-60) at a temperature scanning rate of 5 °C / minute. The melting point of PPO is 69 °C.

[0425] (Intersystem crossing quantum yield)

[0426] It has been reported that the intersystem crossing quantum yield Φ of CBDAC in benzene ISCIt is 92% (see D.P. Specht, P.A. Martic and S. Farid, Tetrahedron, 1982, 38, 1203.).

[0427] Symbol Explanation

[0428] 10, 20, 20A, 30... Organic film manufacturing apparatus (photoluminescent upconversion organic film manufacturing apparatus), 11, 21, 31... Precursor holding part, 12A... First clamping part, 12B... Second clamping part, 13... First heating mechanism, 14... Pressing mechanism (pressing part), 15, 25... Pressure reducing mechanism, 16, 26, 36... Adjustment controller, 22A... First guide plate, 22B... Second guide plate, 23... Second heating mechanism, 24... Moving mechanism, 31A... Support plate, 31B... Support plate, 32... Roller pair, 33... Roller heating mechanism (second heating mechanism), 111... Powder precursor, 112A... Glass substrate, 112B... Glass substrate, 113... Spacer, 114... Holding space, 122... O-ring (buffer member), 131... First heating part, 131A, 131B... First rod heater, 132... Second heating part, 132A, 132B... Second rod heater, 133... Cooling part, 134... Temperature sensor, 135... Heat insulating material, 144... Biasing member, 161... First heating drive circuit, 162... Second heating drive circuit, 163... Cooling drive circuit, 164... Pressure reducing drive circuit, 165... Processor, 231... Rod heater, 321... Roller.

Claims

1. A manufacturing method of an upconversion organic film, wherein, Perform the following steps: Precursor holding step: Hold a powder precursor containing a triplet sensitizer and an organic light-emitting material in the holding space of a precursor holding portion having a holding space with a specified height; Pressing step: Press the powder precursor in the height direction of the holding space; and Temperature adjustment step: Take a direction orthogonal to the height direction as the axial direction, take one end side of the powder precursor in the axial direction as the first end, take the other end side of the powder precursor in the axial direction as the second end, heat the temperature of the first end of the powder precursor, i.e., the first temperature, and the temperature of the second end of the powder precursor, i.e., the second temperature, above the melting point of the organic light-emitting material, and then gradually lower the first temperature and the second temperature while maintaining the temperature difference between the first temperature and the second temperature until it is lower than the freezing point of the organic light-emitting material.

2. The method for manufacturing an upconversion organic film according to claim 1, wherein A temperature reduction rate at which the temperature of the powder precursor gradually decreases is preset with respect to the temperature difference, and the greater the temperature difference, the faster the temperature reduction rate.

3. A method for manufacturing an upconversion organic film, wherein, Perform the following steps: Precursor holding step: Hold a powder precursor containing a triplet sensitizer and an organic light-emitting material in the holding space of a precursor holding portion having a holding space with a specified height; Pressing step: Press the powder precursor in the height direction of the holding space; and Temperature adjustment step: Take a direction orthogonal to the height direction as the axial direction, and relatively move a heating member having a temperature gradient from a high temperature zone above the melting point of the organic light-emitting material to a low temperature zone below the freezing point of the organic light-emitting material along the axial direction relative to the precursor holding portion.

4. The method for manufacturing an upconversion organic film according to any one of claims 1 to 3, wherein In the pressing step, the setting environment of the precursor holding portion is set to a reduced pressure state and the powder precursor is pressed.

5. The method for manufacturing an upconversion organic film according to any one of claims 1 to 4, wherein The crystal of the organic light-emitting material has uniaxial orientation.

6. The method for manufacturing an upconversion organic film according to any one of claims 1 to 5, wherein The organic light-emitting material contains an oxazole derivative, The triplet sensitizer contains a coumarin derivative.

7. An upconversion organic film manufacturing apparatus, which is an upconversion organic film manufacturing apparatus for manufacturing an upconversion organic film, and includes: A precursor holding portion having a holding space with a specified height, and holding a powder precursor containing a triplet sensitizer and an organic light-emitting material in the holding space; A pair of clamping portions that clamp the precursor holding portion in the height direction; A pressing portion that presses at least one of the pair of clamping portions in a direction approaching each other; and The first heating mechanism takes a direction orthogonal to the height direction as the axial direction, takes the end on one end side of the powder precursor in the axial direction as the first end, takes the end on the other end side of the powder precursor in the axial direction as the second end, takes the temperature of the first end as the first temperature, takes the second end as the second temperature, and the first heating mechanism heats the first temperature and the second temperature of the powder precursor to different temperatures to generate a temperature gradient along the axial direction. After the first heating mechanism heats the first temperature and the second temperature to above the melting point of the organic light-emitting material, while maintaining the temperature difference between the first temperature and the second temperature, the first temperature and the second temperature are gradually decreased to below the freezing point of the organic light-emitting material.

8. The upconversion organic film manufacturing apparatus according to claim 7, wherein The first heating mechanism includes: A first heating part, which is arranged on one end side of the clamping part in the axial direction; A second heating part, which is arranged on the other end side of the clamping part in the axial direction and can be driven independently of the first heating part; and A cooling part, which is arranged on the other end side of the clamping part in the axial direction and cools the second end.

9. The upconversion organic film manufacturing apparatus according to claim 8, wherein The first heating part is a first rod heater respectively embedded in one end side of a pair of the clamping parts in the axial direction, The second heating part is a second rod heater respectively embedded in the other end side of a pair of the clamping parts in the axial direction.

10. The upconversion organic film manufacturing apparatus according to any one of claims 7 to 9, wherein The precursor holding part is a pair of substrates separated in the height direction with a spacer therebetween, The holding space is formed by the gap between the pair of substrates, The precursor holding part and a buffer member for absorbing stress in the height direction are arranged between the pair of clamping parts.

11. The optical upconversion organic film manufacturing apparatus according to any one of claims 7 to 10, wherein, It further includes a decompression mechanism, which maintains the ambient environment of the precursor holding part, the pair of clamping parts, the pressing part and the first heating mechanism in a decompressed state.

12. The optical up-conversion organic film manufacturing apparatus according to any one of claims 8 to 11, wherein, It further includes a heat insulating material grounded on the side opposite to the side where the pair of clamping parts clamp the precursor holding part.

13. An upconversion organic film manufacturing apparatus, which is an upconversion organic film manufacturing apparatus for manufacturing an upconversion organic film, and includes: A precursor holding part, which has a holding space with a specified height and holds a powder precursor containing a triplet sensitizer and an organic light-emitting material in the holding space; A pair of guiding parts, which are members that press and clamp the precursor holding part in the height direction, take a direction orthogonal to the height direction as the axial direction, and guide the precursor holding part in a manner capable of relative movement along the axial direction; A second heating mechanism, which heats the guiding part to generate a temperature gradient along the axial direction from a high-temperature region above the melting point of the organic light-emitting material to a low-temperature region below the freezing point of the organic light-emitting material; and A moving mechanism that relatively moves the precursor holding part in the axial direction with respect to the guiding part.

14. The upconversion organic film manufacturing apparatus according to claim 13, wherein the precursor holding part is a pair of substrates separated in the height direction with a spacer therebetween, and the holding space is formed by the gap between the pair of substrates, the pair of guiding parts are a pair of guide plates that sandwich the precursor holding part in the height direction, the second heating mechanism heats the guide plates to generate the temperature gradient such that the temperatures at positions opposite to each other in the pair of guide plates are the same, the moving mechanism presses the precursor holding part between the pair of guide plates in the axial direction, thereby relatively moving the precursor holding part with respect to the guiding part.

15. The upconversion organic film manufacturing apparatus according to claim 13, wherein the precursor holding part includes: a pair of substrates separated in the height direction with a spacer therebetween; and a pair of support plates that sandwich the pair of substrates and are longer than the substrates in the axial direction, the holding space is formed by the gap between the pair of substrates, the pair of guiding parts are constituted by arranging a plurality of roller pairs in the axial direction, the rollers in the roller pair are in pairs in the height direction, rotate about a rotation axis orthogonal to the height direction and the axial direction, and sandwich the precursor holding part with the pair of rollers in the height direction, the moving mechanism relatively moves the precursor holding part in the axial direction with respect to the pair of guiding parts by rotating the rollers, the second heating mechanism individually adjusts the temperatures of the respective roller pairs arranged in the axial direction such that the roller pairs with temperatures from the high-temperature region to the low-temperature region are arranged in sequence in the axial direction.

16. The upconversion organic film manufacturing apparatus according to any one of claims 13 to 15, wherein the second heating mechanism heats the guiding part to generate a temperature gradient in the order of the low-temperature region, the high-temperature region, and the low-temperature region along the axial direction.

17. An upconversion organic film that contains a triplet sensitizer and an organic light-emitting material, the organic light-emitting material has ultraviolet light-emitting properties, the upconversion organic film is a film having crystallinity.

18. The upconversion organic film according to claim 17, wherein the triplet sensitizer absorbs excitation light to generate excited triplet excitons, the organic light-emitting material emits light having a maximum peak in a wavelength region that is shorter than the maximum peak wavelength on the longest wavelength side of the absorption spectrum of the triplet sensitizer and is 400 nm or less.

19. The upconversion organic film according to claim 17 or 18, wherein the crystal of the organic light-emitting material has uniaxial orientation.

20. The upconversion organic film according to any one of claims 17 to 19, wherein the organic light-emitting material contains an oxazole derivative.

21. The upconversion organic film according to any one of claims 17 to 20, wherein The fluorescence quantum yield of the organic light-emitting material is above 40%.

22. The upconversion organic film according to any one of claims 17 to 21, wherein the triplet sensitizer does not contain metal atoms in the molecule.

23. The upconversion organic film according to any one of claims 17 to 22, wherein the triplet sensitizer only contains hydrogen atoms, carbon atoms, oxygen atoms and nitrogen atoms in the molecule.

24. The upconversion organic film according to any one of claims 17 to 23, wherein the triplet sensitizer comprises a coumarin derivative.

25. The upconversion organic film according to any one of claims 17 to 24, wherein the molar ratio of the triplet sensitizer to the organic light-emitting material is 1:1000 to 1:100000.

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