Method for manufacturing photo-upconverted organic film, apparatus for manufacturing photo-upconverted organic film, and photo-upconverted organic film

Abstract

To provide a method for producing a photo-upconversion organic film that has a low environmental impact and can produce a high-quality photo-upconversion organic film, a photo-upconversion organic film manufacturing apparatus, and a photo-upconversion organic film. [Solution] The method involves 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 section having a holding space of height in the Z direction; a pressing step (S2) in which the powder precursor is pressed along the Z direction; and a temperature control step in which the first temperature, which is the temperature of the first end of the powder precursor, and the second temperature, which is the temperature of the second end of the powder precursor, are heated to a temperature above the melting point of the organic light-emitting material, and then the temperature of the first and second temperatures is gradually reduced to below the freezing point of the organic light-emitting material while maintaining the temperature difference between the first and second temperatures.

Description

[Technical Field]

[0001] The present invention relates to a method for producing an organic film that can be upconverted by light, an apparatus for producing an organic film that can be upconverted by light, and an organic film that can be upconverted by light. [Background technology]

[0002] Optical upconversion is attracting attention as a technology that converts low-energy light into high-energy light. For example, Non-Patent Literature 1 proposes a mechanism in which, in a combination of a sensitizer (e.g., PtOEP) with a large intersystem crossover rate constant from the lowest excited singlet state to the lowest excited triplet state and a light-emitting molecule (e.g., diphenylanthracene (DPA)), the lowest excited singlet state is generated and light is emitted by triplet-triplet annihilation (TTA) between light-emitting molecules (DPA) excited to the lowest excited triplet state by energy transfer from the sensitizer. In addition to Non-Patent Document 1, technologies related to optical upconversion are also described in, for example, Patent Documents 1-2 and Non-Patent Documents 2-7. Furthermore, Non-Patent Documents 6-7 disclose the manufacturing of photo-upconversion organic films. Specifically, a sensitizer and a light-emitting molecule are dissolved in a solvent, and then the solvent is evaporated to mix the sensitizer and the light-emitting molecule. The mixture is then dropped onto a substrate, heated and dissolved in an inert atmosphere, and then rapidly cooled to produce a photo-upconversion organic film. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-111751 [Patent Document 2] U.S. Patent No. 10950803 [Non-patent literature]

[0004] [Non-Patent Document 1] Journal of Applied Physics,101,023101(2007) [Non-Patent Document 2] J.Phys.Chem.Lett.,2013,4,4113-4118 [Non-Patent Document 3] J.Phys.Chem.C,2014,118,14256-14265 [Non-Patent Document 4] Mater. Horiz., 2017, 4, 83-87 [Non-Patent Document 5] J.Mater.Chem.C,2018,6,5609-5615 [Non-Patent Document 6] J.Mater.Chem.C,2014,2,2837-2841 [Non-Patent Document 7] ACS Appl. Mater. Interfaces 2016,8,15732-15740 [Overview of the project] [Problems that the invention aims to solve]

[0005] In the above-mentioned Non-Patent Documents 6-7, a mixture of the sensitizer and luminescent molecule is obtained by organically dissolving the sensitizer and luminescent molecule in a solvent and then volatilizing the organic solvent. However, the use of organic solvents raises concerns about environmental impact, and a more environmentally friendly method is desired. Furthermore, in the methods described in Non-Patent Documents 6 and 7 above, which involve heating and rapidly cooling the entire mixture, an organic photo-upconversion film is produced from the molten material as amorphous glass, but this method suffers from low upconversion efficiency. Therefore, there is a need for a high-quality organic photo-upconversion film and a method for producing the same.

[0006] Furthermore, the application of photo-upconversion organic films is being considered to efficiently and effectively utilize sunlight. Ultraviolet (UV) light contained in sunlight consists of high-energy photons and is used in a variety of applications. For example, UV light is used in the production of photocatalysts for green hydrogen and hydrocarbons, photopolymerization, and disinfection. However, since only about 4% of the photons contained in sunlight on Earth constitute ultraviolet light, the efficient and effective use of sunlight is hindered. Therefore, there is a need for photo-upconversion organic films that can efficiently convert visible light to ultraviolet light at an excitation threshold intensity equivalent to or lower than the intensity of sunlight on Earth.

[0007] The object of the present invention is to provide a method for producing a photo-upconversion organic film that has a low environmental impact and can produce a high-quality photo-upconversion organic film, a photo-upconversion organic film manufacturing apparatus, and a photo-upconversion organic film.

[0008] Another object of the present invention is to provide an organic photo-upconversion film that can stably upconvert visible light to ultraviolet light in the atmosphere and exhibit high upconversion quantum efficiency at an excitation light intensity lower than that of sunlight irradiating the Earth's surface (for example, an intensity of about 0.3 times that of sunlight). [Means for solving the problem]

[0009] A method for manufacturing a photo-upconversion organic film according to a first aspect of the present invention includes: a precursor holding step of holding a powder precursor containing a triplet sensitizer and an organic light-emitting material in a holding space of a precursor holding section having a holding space of a predetermined height; a pressing step of pressing the powder precursor along the height direction of the holding space; and a temperature control step of heating the first temperature, which is the temperature of the first end of the powder precursor, and the second temperature, which is the temperature of the second end of the powder precursor, to a temperature above the melting point of the organic light-emitting material, while maintaining the temperature difference between the first temperature and the second temperature, and gradually decreasing the first temperature and the second temperature to below the freezing point of the organic light-emitting material, with one direction perpendicular to the height direction being the axial direction, the end of the powder precursor on one side in the axial direction being the first end, and the end of the powder precursor on the other side in the axial direction being the second end.

[0010] In the method for manufacturing a photo-upconverted organic film according to the first embodiment, a cooling rate for gradually decreasing the temperature of the powder precursor is predetermined with respect to the temperature difference, and it is preferable to increase the cooling rate as the temperature difference increases.

[0011] A method for manufacturing a photo-upconversion organic film according to a second aspect of the present invention includes: a precursor holding step of holding a powder precursor containing a triplet sensitizer and an organic light-emitting material in a holding space of a precursor holding section having a holding space of a predetermined height; a pressing step of pressing the powder precursor along the height direction of the holding space; and a temperature control step of moving a heating member relative to the precursor holding section in the axial direction, with the axial direction being one direction perpendicular to the height direction and the heating member having a temperature gradient from a high temperature range above the melting point of the organic light-emitting material to a low temperature range below the solidification point of the organic light-emitting material along the axial direction.

[0012] In the method for manufacturing a photo-upconverted organic film according to the first and second embodiments, it is preferable that the pressing step is performed by reducing the pressure of the environment in which the precursor holding unit is installed and pressing the powder precursor.

[0013] In the method for manufacturing an organic light-upconversion film according to the first and second embodiments, it is preferable that the crystals of the organic light-emitting material have uniaxial orientation.

[0014] In the method for producing a photo-upconversion organic film according to the first and second embodiments, it is preferable that the organic light-emitting material includes an oxazole derivative and the triplet sensitizer includes a coumarin derivative.

[0015] A photo-upconversion organic film manufacturing apparatus according to a third aspect of the present invention comprises: a precursor holding section having a holding space of a predetermined height and holding a powder precursor containing a triplet sensitizer and an organic light-emitting material in the holding space; a pair of clamping sections that clamp the precursor holding section in the height direction; a pressing section that presses at least one of the pair of clamping sections toward each other; and a first heating mechanism that sets the first temperature and the second temperature of the powder precursor to different temperatures, with the axial direction being one direction perpendicular to the height direction, the first end of the powder precursor in the axial direction being the first end, the other end of the powder precursor in the axial direction being the second end, the temperature of the first end being the first temperature, and the temperature of the second end being the second temperature, thereby generating a temperature gradient along the axial direction; wherein the first heating mechanism heats the first temperature and the second temperature to above the melting point of the organic light-emitting material, and then gradually reduces the first temperature and the second temperature to below the freezing point of the organic light-emitting material while maintaining the temperature difference between the first temperature and the second temperature.

[0016] In the photo-upconversion organic film manufacturing apparatus according to the third embodiment, the first heating mechanism preferably comprises a first heating unit provided on one end of the clamping unit in the axial direction, a second heating unit provided on the other end of the clamping unit in the axial direction and capable of being driven independently of the first heating unit, and a cooling unit provided on the other end of the clamping unit in the axial direction and for cooling the second end.

[0017] In the photo-upconversion organic film manufacturing apparatus according to the third embodiment, it is preferable that the first heating section is a first rod heater embedded in one end of the pair of clamping sections in the axial direction, and the second heating section is a second rod heater embedded in the other end of the pair of clamping sections in the axial direction.

[0018] In the photo-upconversion organic film manufacturing apparatus according to the third embodiment, the precursor holding portion is a pair of substrates spaced apart in the height direction via a spacer, the holding space is formed by the gap between the pair of substrates, and it is preferable that the precursor holding portion and a buffer member that absorbs stress in the height direction are provided between the pair of clamping portions.

[0019] In the photo-upconversion organic film manufacturing apparatus according to the third embodiment, it is preferable to further include a depressurization mechanism for maintaining the environment surrounding the precursor holding section, the pair of clamping sections, the pressing section, and the first heating mechanism in a depressurized state.

[0020] In the photo-upconversion organic film manufacturing apparatus according to the third embodiment, it is preferable to further provide a heat insulating material that is in contact with the side of the pair of clamping portions opposite to the side that clamps the precursor holding portion.

[0021] A photo-upconversion organic film manufacturing apparatus according to a fourth aspect of the present invention comprises: a precursor holding section having a holding space of a predetermined height and holding a powder precursor containing a triplet sensitizer and an organic light-emitting material in the holding space; a pair of guide sections that press and clamp the precursor holding section in the height direction, with one direction perpendicular to the height direction as the axial direction, and guide the precursor holding section so that it can move relative to the axial direction; a second heating mechanism that heats the guide sections such that a temperature gradient is generated along the axial direction from a high temperature range above the melting point of the organic light-emitting material to a low temperature range below the freezing point of the organic light-emitting material; and a moving mechanism that moves the precursor holding section relative to the guide sections in the axial direction.

[0022] In the photo-upconversion organic film manufacturing apparatus according to the fourth embodiment, the precursor holding portion is a pair of substrates spaced apart in the height direction via a spacer, the holding space is formed by the gap between the pair of substrates, the pair of guide portions is a pair of guide plates that sandwich the precursor holding portion in the height direction, the second heating mechanism heats the guide plates so that a temperature gradient is created in which the temperatures of opposing positions on the pair of guide plates are the same, and the moving mechanism preferably presses the precursor holding portion between the pair of guide plates in the axial direction to move the precursor holding portion relative to the guide portions.

[0023] In the photo-upconversion organic film manufacturing apparatus according to the fourth embodiment, the precursor holding section comprises a pair of substrates spaced apart in the height direction via a spacer, and a pair of support plates that sandwich the pair of substrates and have an axial length longer than that of the substrates, with the holding space being formed by the gap between the pair of substrates, and the pair of guide sections is composed of a plurality of roller pairs arranged in the axial direction, each roller rotating around a rotation axis perpendicular to the height direction and the axial direction, with the pair of rollers forming a pair in the height direction, and the precursor holding section is sandwiched between the pair of rollers forming a pair in the height direction, and the moving mechanism moves the precursor holding section relative to the pair of guide sections in the axial direction by rotating the rollers, and the second heating mechanism preferably individually controls the temperature of each of the roller pairs arranged in the axial direction such that the roller pairs with temperatures in the high temperature range are arranged in order from the roller pairs with temperatures in the low temperature range along the axial direction.

[0024] In the photo-upconversion organic film manufacturing apparatus according to the fourth embodiment, it is preferable that the second heating mechanism heats the guide portion such that a temperature gradient is generated along the axial direction in the order of the low temperature region, the high temperature region, and the low temperature region.

[0025] According to one aspect of the present invention, a photo-upconversion organic film is provided, comprising a triplet sensitizer and an organic light-emitting material, wherein the organic light-emitting material is a film having ultraviolet light emission properties and crystalline properties.

[0026] In a photo-upconversion organic film according to one aspect of the present invention, it is preferable that 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 longest wavelength maximum peak wavelength in the absorption spectrum of the triplet sensitizer, and in a wavelength region of 400 nm or less.

[0027] In a photo-upconversion organic film according to one aspect of the present invention, it is preferable that the crystals of the organic light-emitting material have uniaxial orientation.

[0028] In a photo-upconversion organic film according to one aspect of the present invention, the organic light-emitting material preferably includes an oxazole derivative.

[0029] In a photo-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.

[0030] In a photo-upconversion organic film according to one aspect of the present invention, it is preferable that the triplet sensitizer does not contain metal atoms in its molecule.

[0031] In a photo-upconversion organic film according to one aspect of the present invention, it is preferable that the triplet sensitizer contains only hydrogen atoms, carbon atoms, oxygen atoms, and nitrogen atoms in its molecule.

[0032] In a photo-upconversion organic film according to one aspect of the present invention, the triplet sensitizer preferably contains a coumarin derivative.

[0033] In a photo-upconversion organic film according to one aspect of the present invention, the molar ratio of the triplet sensitizer to the organic light-emitting material is preferably 1:1000 to 1:100000. [Effects of the Invention]

[0034] According to one aspect of the present invention, it is possible to provide a method for producing a photo-upconversion organic film that has a low environmental impact and produces a high-quality photo-upconversion organic film, a photo-upconversion organic film production apparatus, and a photo-upconversion organic film.

[0035] According to one aspect of the present invention, it is possible to provide an organic photo-upconversion film that can stably upconvert visible light to ultraviolet light in the atmosphere and exhibit high upconversion quantum efficiency at an excitation light intensity lower than that of sunlight irradiating the Earth's surface (for example, an intensity of about 0.3 times that of sunlight). [Brief explanation of the drawing]

[0036] [Figure 1] This figure shows a schematic configuration of an organic film manufacturing apparatus according to the first embodiment. [Figure 2] This block diagram shows a schematic configuration of the organic film manufacturing apparatus according to this embodiment. [Figure 3] This is an enlarged cross-sectional view of the precursor holding portion of the precursor holding portion and the pair of clamping portions of the precursor holding portion of this embodiment. [Figure 4] This is a flowchart showing the method for producing the photo-upconversion organic film according to this embodiment. [Figure 5] This figure shows the temperature change of the pair of clamping parts in the temperature control step of this embodiment. [Figure 6] This figure shows the cooling process of the powder precursor during the temperature control step in this embodiment. [Figure 7] This is a schematic diagram showing the general configuration of the organic film manufacturing apparatus in the second embodiment. [Figure 8] This is a schematic diagram showing the general configuration of an organic film manufacturing apparatus according to a modified example of this embodiment. [Figure 9] This is a flowchart showing the method for producing the photo-upconversion organic film according to this embodiment. [Figure 10] This is a schematic diagram showing the general configuration of the organic film manufacturing apparatus in the third embodiment. [Figure 11] This is a flowchart showing the method for producing the photo-upconversion organic film according to this embodiment. [Figure 12] This is a schematic diagram illustrating the upconversion mechanism in photo-upconverted organic films. [Figure 13] Figures (a) to (e) show the temperature changes of a pair of clamping portions when the photo-upconversion organic film according to the example is formed. [Figure 14] These are optical microscope images of the photo-upconversion organic films according to the examples. [Figure 15] This figure shows the powder X-ray diffraction (PXRD) patterns of PPO powder and photo-upconversion organic films. [Figure 16] This figure shows the crystal structure of PPO obtained by Pawley and Rietveld analysis. [Figure 17] This figure shows the photophysical properties of the photo-upconversion organic film and CBDAC. [Figure 18] (A) is a schematic diagram of the apparatus used to measure photophysical properties, and (B) is a magnified cross-sectional view of the sample used for photophysical measurement. [Figure 19] Figures (A) and (B) show the dependence of the optical upconversion quantum efficiency on the excitation intensity at a wavelength of 440 nm. [Figure 20] This graph shows the relationship between the excitation threshold intensity (Ith) of an organic photo-upconversion film and the molar ratio (MA / MS) of the organic light-emitting material to the triplet sensitizer. [Figure 21] This graph shows the dependence of light upconversion emission intensity on sunlight intensity. [Figure 22] This graph shows the photostability of photo-upconversion organic films. [Figure 23] This is a schematic diagram of an experimental method demonstrating an example of the practical application of photo-upconversion organic films. [Modes for carrying out the invention]

[0037] [First Embodiment] The following describes an optical upconversion organic film manufacturing apparatus and a method for manufacturing an optical upconversion organic film according to the first embodiment of the present invention. The optical upconversion organic film manufacturing apparatus will be simply referred to as the organic film manufacturing apparatus. Figure 1 is a cross-sectional view showing the schematic configuration of the organic film manufacturing apparatus 10 according to this embodiment. Figure 2 is a block diagram of the organic film manufacturing apparatus 10 according to this embodiment. The organic film manufacturing apparatus 10 of this embodiment is a manufacturing apparatus for manufacturing photo-upconversion organic films, and as shown in Figure 1, it comprises a precursor holding section 11, a pair of clamping sections (first clamping section 12A, second clamping section 12B) that clamp the precursor holding section 11, a first heating mechanism 13, a pressing mechanism 14, a depressurization mechanism 15 (see Figure 2), and a control controller 16 (see Figure 2) that controls the first heating mechanism 13.

[0038] The precursor holding section 11 holds a powder precursor 111 for forming a photo-upconversion organic film. The powder precursor 111 is a powder containing a triplet sensitizer and an organic light-emitting material. In this embodiment, a powder precursor 111 is used in which the molar ratio of the triplet sensitizer to the organic light-emitting material is 1:10000 to 1:10000. In this embodiment, CBDAC (3,3-carbonylbis(7-diethylaminocoumarin)) powder is used as the triplet sensitizer, and PPO (2,5-diphenyloxazole) powder having uniaxially oriented crystals is used as an example of the organic light-emitting material. The triplet sensitizer and organic light-emitting material that can be used in the manufacturing apparatus and manufacturing method of this embodiment are not limited to the examples of CBDAC and PPO, and can be selected from, for example, the triplet sensitizer and organic light-emitting material described in the fourth embodiment described later.

[0039] Figure 3 is an enlarged cross-sectional view of the holding portion of the precursor holding portion 11, which comprises the precursor holding portion 11 and a pair of clamping portions 12A and 12B. As shown in Figure 3, the precursor holding section 11 comprises 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 enclosed 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 in which the powder precursor 111 is stored. Here, the opposing surfaces of the pair of glass substrates 112A and 112B are defined as the XY plane, and the direction perpendicular to the XY plane is defined as the Z direction.

[0040] The first clamping portion 12A and the second clamping portion 12B are members that clamp the precursor holding portion 11 from the Z direction. The first clamping portion 12A is positioned on the +Z side of the precursor holding portion 11, and the second clamping portion 12B is positioned on the -Z side of the precursor holding portion 11. It is preferable that these first clamping portion 12A and the second clamping portion 12B are made of a material with high thermal conductivity, such as metal. The surface of the first clamping portion 12A facing the second clamping portion 12B, and the surface of the second clamping portion 12B facing the first clamping portion 12A, each have XY planes facing the glass substrates 112A and 112B, respectively. A holder 121 holding the precursor holding portion 11 is positioned between the first clamping portion 12A and the second clamping portion 12B. The holder 121 may be provided integrally with, for example, the first clamping portion 12A or the second clamping portion 12B.

[0041] The holder 121 is provided with a recess or through-hole in the center of the XY plane, for example, to hold the precursor holding portion 11. An O-ring 122 is placed in the recess or through-hole of the holder 121 as a buffer when the precursor holding portion 11 is clamped between the first clamping portion 12A and the second clamping portion 12B, and the precursor holding portion 11 is positioned on the inner diameter side surrounded by the O-ring 122. The O-ring 122 has a thickness in the Z direction that is greater than or equal to the height of the holder 121 in the Z direction, and is clamped and pressed by the first clamping portion 12A and the second clamping portion 12B, causing it to elastically deform 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, the inner diameter side of the O-ring 122 becomes a sealed space, and the inner diameter side of the O-ring 122 is maintained in a reduced-pressure environment by being depressurized by the depressurization mechanism 15 described later.

[0042] The first heating mechanism 13 controls the temperature of the first clamping portion 12A and the second clamping portion 12B. Here, with the axial direction along the XY plane being defined as the X direction, the first heating mechanism 13 comprises a first heating section 131 provided on one end (-X side) in the X direction of the first clamping section 12A and the second clamping section 12B, a second heating section 132 provided on the other end (+X side) in the X direction of the first clamping section 12A and the second clamping section 12B, and a cooling section 133 connected to the +X side in the X direction of the first clamping section 12A and the second clamping section 12B.

[0043] The first heating section 131 is a component that heats the -X side of the first clamping section 12A and the second clamping section 12B. The first heating section 131 is composed of first rod heaters 131A and 131B, respectively, which are embedded in the first clamping section 12A and the second clamping section 12B on the -X side of the holder 121, as shown in Figure 1, for example. The first rod heater 131A embedded in the first clamping section 12A and the first rod heater 131B embedded in the second clamping section 12B are in 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 controlled to the same temperature by, for example, being connected to the same drive circuit.

[0044] The second heating section 132 is a component that heats the +X side of the first clamping section 12A and the second clamping section 12B. The second heating section 132 is composed of second rod heaters 132A and 132B, respectively, which are embedded in the first clamping section 12A and the second clamping section 12B at a position on the +X side of the holder 121, as shown in Figure 1, for example. The second rod heater 132A embedded in the first clamping section 12A and the second rod heater 132B embedded in the second clamping section 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 controlled to the same temperature by, for example, being connected to the same drive circuit. Furthermore, the second rod heaters 132A and 132B are driven by a drive circuit independent of the first rod heaters 131A and 131B that constitute the first heating section 131, and can be controlled to a different temperature than the first heating section 131.

[0045] The cooling unit 133 is composed of a heat transfer unit 133A and a cooling element 133B. The heat transfer section 133A is a highly thermally conductive member connected to the +X side of the first clamping section 12A and the second clamping section 12B, and is composed of, for example, a metal foil such as copper foil. The cooling element 133B cools the heat transferred to the heat transfer section 133A. It is preferable to use an element that allows for appropriate control of the cooling efficiency as the cooling element 133B. For example, a Peltier element, a fan or heatsink utilizing air or water cooling can be used.

[0046] Furthermore, the first clamping portion 12A and the second clamping portion 12B are each equipped with a plurality of temperature sensors 134(I) to 134(V) along the X direction. Examples of these temperature sensors 134(I) to 134(V) include thermocouples embedded inside the first clamping portion 12A and the second clamping portion 12B.

[0047] Furthermore, the first clamping portion 12A and the second clamping portion 12B are clamped from the Z direction by a pair of heat insulating materials 135. Specifically, the heat insulating materials 135 are positioned on the +Z side of the first clamping portion 12A and the -Z side of the second clamping portion 12B, respectively, so as to overlap with the holder 121 when viewed from the Z direction.

[0048] In this first heating mechanism 13, it is possible to control the heating temperature in the first heating section 131, the heating temperature in the second heating section 132, and the cooling temperature in the cooling section 133, respectively. This makes it possible to create a temperature gradient along the X direction for the first clamping section 12A and the second clamping section 12B, and to raise or lower the overall temperature of the first clamping section 12A and the second clamping section 12B while maintaining a constant temperature difference ΔT on the ±X side of the first clamping section 12A and the second clamping section 12B. Note that "constant" as used here means that an error within a predetermined range is permitted, and is not limited to a strict temperature difference ΔT; it is sufficient for the temperature difference ΔT to be approximately constant in temperature raising and lowering control. Furthermore, the first clamping portion 12A and the second clamping portion 12B are clamped by the insulating material 135, thereby suppressing heat loss due to heat dissipation in the region between the first heating portion 131 and the second heating portion 132 (the position overlapping with the precursor holding portion 11 in the Z direction).

[0049] The pressing mechanism 14 corresponds to the pressing portion of the present invention and presses the first clamping portion 12A and the second clamping portion 12B toward each other. In other words, it presses the pair of glass substrates 112A and 112B of the precursor holding portion 11, which are clamped by the first clamping portion 12A and the second clamping portion 12B toward each other, thereby applying a load to the powder precursor 111 in the holding space 114. Here, the pressing mechanism 14 may be configured to press both the first clamping portion 12A and the second clamping portion 12B in a direction that brings them closer to each other, or it may be configured to press either the first clamping portion 12A or the second clamping portion 12B toward the other.

[0050] In this embodiment, as shown in Figure 1, through holes 124 extending in the Z direction are formed at the ±X side ends of the first clamping portion 12A and the second clamping portion 12B, and a fixed shaft 141 is inserted through these through holes 124. The +Z side of these fixed shafts 141 is fixed to a fixed stage 142. Furthermore, the movable stage 143 is inserted through the fixed shaft 141, and the movable stage 143 and the fixed stage 142 clamp the insulation material 135 on the +Z side, the first clamping portion 12A, the second clamping portion 12B, and the insulation material 135 on the -Z side. A biasing member 144, such as a spring, is positioned on the -Z side of the movable stage 143 to bias the movable stage 143 toward the fixed stage 142, and the biasing force of the biasing member 144 presses the movable stage 143 toward the fixed stage 142. As a result, as described above, the precursor holding portion 11 is clamped from the Z direction by the first clamping portion 12A and the second clamping portion 12B, and the powder precursor 111 sandwiched between the pair of glass substrates 112A and 112B is pressed in the Z direction. In addition, the pair of insulation materials 135 are in contact with the first clamping portion 12A and the second clamping portion 12B respectively, suppressing heat loss. In this embodiment, the movable stage 143 is shown being pressed towards the fixed stage 142 by the biasing member 144, but the movable stage 143 may also be pressed towards the fixed stage 142 by a driving force output from a drive source such as a motor.

[0051] Specifically, the depressurization mechanism 15 consists of a vacuum chamber 151 and a vacuum pump 152, as shown in Figure 2. In this embodiment, the first clamping part 12A, the second clamping part 12B, the first heating mechanism 13, the pressing mechanism 14, and the precursor holding part 11 are arranged inside the vacuum chamber 151. The depressurization mechanism 15 then uses the vacuum pump 152 to discharge the gas inside the vacuum chamber 151, thereby creating a depressurized state, preferably a vacuum, inside the vacuum chamber 151. In this embodiment, during the process of bringing the first clamping portion 12A and the second clamping portion 12B closer together by the pressing mechanism 14, the air between the pair of glass substrates 112A and 112B of the precursor holding portion 11 is discharged by reducing the pressure inside the vacuum chamber 151. As a result, the sealed space surrounded by the O-ring 122 is maintained in a reduced pressure state (preferably a vacuum state), which suppresses the inclusion of air bubbles when the powder precursor 111 melts and a photo-upconversion organic film is formed, making it possible to manufacture a higher quality photo-upconversion organic film.

[0052] As shown in Figure 2, the control controller 16 controls the first heating mechanism 13, the pressing mechanism 14, and the depressurization mechanism 15. Specifically, the control 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 controls the vacuum pump 152, and a processor 165 that outputs control signals to these drive circuits. If the pressing mechanism 14 uses a drive source such as a motor to press the powder precursor 111, a drive circuit to control the drive source may be provided.

[0053] By making the first heating drive circuit 161 and the second heating drive circuit 162 independent of each other, it becomes possible to independently control the heating temperature in the first heating section 131 and the heating temperature in the second heating section 132, as described above, and to generate a temperature gradient along the X-axis. The vacuum drive circuit 164 reduces the pressure inside the vacuum chamber 151 by driving the vacuum pump 152. Furthermore, as described above, the processor 165 raises or lowers the overall temperature of the first clamping section 12A and the second clamping section 12B while maintaining the temperature difference ΔT between the heating temperature of the first heating section 131 and the heating temperature of the second heating section 132. In this case, it is preferable that the processor 165 controls the cooling drive circuit 163 based on the temperature measured by each temperature sensor 134(I) to 134(V) and provides feedback control of the cooling efficiency of the cooling section 133.

[0054] [Method for manufacturing photo-upconversion organic films] Next, a method for producing an organic film using the organic film manufacturing apparatus 10 described above will be explained. Figure 4 is a flowchart showing the method for producing the photo-upconversion organic film according to this embodiment. In this embodiment, when manufacturing an organic film for photo-upconversion, first, a powder precursor 111 is prepared and held in the precursor holding unit 11 (Step S1: Precursor holding step). As described above, the powder precursor 111 is a powder containing a triplet sensitizer and an organic light-emitting material. The powder precursor 111 prepared as described above is then filled into the gap (holding space 114) between a pair of glass substrates 112A and 112B that are arranged opposite each other via a spacer 113.

[0055] Next, the precursor holding portion 11 is set in the holder 121, and the biasing member 144 biases the second clamping portion 12B toward the first clamping portion 12A (step S2: pressing step). As a result, the powder precursor 111, which is held between the pair of glass substrates 112A and 112B, is pressed in the Z direction. In step S2, the vacuum chamber 151 is depressurized by the depressurization mechanism 15, and the powder precursor 111 is pressed under the depressurized conditions.

[0056] Subsequently, the control controller 16 controls the first heating mechanism 13 via the first heating drive circuit 161, the second heating drive circuit 162, and the cooling drive circuit 163, and performs a temperature control step to control the temperature of the powder precursor 111 by heating the first clamping portion 12A and the second clamping portion 12B.

[0057] Figure 5 shows the temperature changes of the first clamping portion 12A and the second clamping portion 12B during the temperature control step. In Figure 5, line L1 is the temperature measured by the temperature sensor 134(I) of the first clamping portion 12A located at the -X side end. Line L2 is the temperature measured by the temperature sensor 134(II) of the first clamping portion 12A located second from the -X side. Line L3 is the temperature measured by the temperature sensor 134(III) of the first clamping portion 12A located third (center) from the -X side. Line L4 is the temperature measured by the temperature sensor 134(IV) of the first clamping portion 12A located second from the +X side. Line L5 is the temperature measured by the temperature sensor 134(V) of the first clamping portion 12A located at the +X side end. Line L6 is the temperature measured by the temperature sensor 134(II) of the second clamping portion 12B located second from the -X side. Line L7 represents the temperature measured by the temperature sensor 134(III) of the second clamping section 12B, which is located third from the -X side. Line L8 represents the temperature measured by the temperature sensor 134(IV) of the second clamping section 12B, which is located second from the +X side.

[0058] In the temperature control step, first, the processor 165 controls the temperature of the pair of clamping parts (first clamping part 12A, second clamping part 12B) to at least the melting point T of the organic light-emitting material (PPO) in order to melt the powder precursor 111. melt(PPO) Heat to the above point (Step S3: t0~t1 in Figure 5). At this time, the processor 165 raises the temperature of the pair of clamping parts (first clamping part 12A and second clamping part 12B) at a heating rate of, for example, 5°C / min, so that the temperature difference ΔT between the -X side end and the +X side end of the pair of clamping parts (first clamping part 12A and second clamping part 12B) remains constant.

[0059] Here, the temperature of the -X side end (first end) of the powder precursor 111 held by the precursor holding section 11 is shown by line L2 measured by the temperature sensor 134(II), and the temperature of the +X side end (second end) of the powder precursor 111 is shown by line L4 measured by the temperature sensor 134(IV). The temperature of the second heating section 132, which is set to a lower temperature than the first heating section 131, is the melting point T. melt(PPO) If the above conditions are met, the portion where the powder precursor 111 is located (corresponding to temperature sensors 134(II) to 134(IV)) will have a melting point T melt(PPO) That concludes the explanation. Furthermore, in this embodiment, the temperature of the pair of clamping parts 12A and 12B is raised and lowered while maintaining a constant temperature difference ΔT between the two ends of the pair of clamping parts 12A and 12B. In this case, the temperature difference ΔT' between the temperature at the -X end of the powder precursor 111 (the first temperature, measured by the temperature sensor 134(II)) and the temperature at the +X end of the powder precursor 111 (the second temperature, measured by the temperature sensor 134(IV)) is also maintained constant while being 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 at the -X end of the powder precursor 111 and the second temperature at the +X end.

[0060] Next, the processor 165 maintains the temperatures of the first heating section 131 and the second heating section 132 for a predetermined time (step S4: t1-t2 in Figure 5). This causes the powder precursor 111 held in the precursor holding section 11 to melt. The time in step S4 is the time required to melt the powder precursor 111, and can be appropriately set according to the amount of powder precursor 111 held in the precursor holding section 11, the types and molar ratios of the triplet sensitizer and organic light-emitting material constituting the powder precursor 111, etc.

[0061] After this, the processor 165 maintains the temperature difference ΔT between the first heating section 131 and the second heating section 132, and reduces the temperatures of the first heating section 131 and the second heating section 132 at a predetermined cooling rate (step S5: t2~ in Figure 5). Figure 6 shows the cooling process of the powder precursor 111 in step S5. In this embodiment, by lowering the temperature of the first heating section 131 and the second heating section 132 while maintaining a temperature difference ΔT, the powder precursor 111 is cooled while a temperature gradient is created, as shown in Figure 6. Therefore, the powder precursor 111 cools down sequentially from the +X side to the -X side until it reaches its solidification point T. solid(PPO) The temperature will be cooled to below a certain level. In this embodiment, uniaxially oriented PPO is used as the organic light-emitting material. Therefore, the molten powder precursor 111 along the X-axis, which is the direction of the temperature gradient, is sequentially cooled and crystallized. The cooling rate in step S5 is appropriately set based on the type and molar ratio of the triplet sensitizer and organic light-emitting material constituting the powder precursor 111 held in the precursor holding section 11, as well as the temperature difference ΔT (or temperature difference ΔT'). For example, in this embodiment, CBDAC is used as the triplet sensitizer and PPO as the organic light-emitting material, with a molar ratio of 1:30000, and the temperature gradient along the X direction is 20°C / 24 mm (=0.83°C / mm). If the length along the X direction from the first heating section 131 to the second heating section 132 is 24 mm, then the temperature difference ΔT should be set to 20°C. In this case, it is preferable to set the cooling rate to -3°C / min. The larger the temperature difference ΔT (or temperature difference ΔT'), the faster the cooling rate can be increased to achieve similar crystal growth. As a result, a photo-upconversion organic film having crystal orientation along the X direction is manufactured.

[0062] In this embodiment, multiple temperature sensors 134(I) to 134(V) are arranged along the X direction. Therefore, in the temperature control steps from step S3 to step 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-controlled so that the temperatures of each temperature sensor 134(I) to 134(V) reach the desired temperature, making it possible to control the temperature difference ΔT and temperature difference ΔT' with high precision.

[0063] [Effects of this embodiment] The method for manufacturing a photo-upconversion organic film according to this embodiment includes a precursor holding step (step S1), a pressing step (step S2), and a temperature control step (steps S3 to S5). 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 of a predetermined height provided in the precursor holding section 11. In the pressing step, the powder precursor 111 is pressed along the height direction (Z direction) of the holding space 114. In the temperature control step, the first temperature at the -X end and the second temperature at the +X end of the powder precursor 111 are controlled to the melting point T of the organic light-emitting material. melt(PPO)After heating as described above (steps S3 to S4), the temperature difference ΔT' between the first and second temperatures is maintained while the first and second temperatures are brought to the freezing point T of the organic light-emitting material. solid(PPO) Gradually reduce it to less than (Step S5).

[0064] In this method for manufacturing photo-upconverted organic films, step S5 brings the molten powder precursor 111 to a solidification point T in order from the +X side. solid(PPO) By cooling to below a certain temperature, it is possible to produce a photo-upconversion organic film with crystal growth along a single axis. This makes it possible to produce a photo-upconversion organic film of good quality with high photo-upconversion efficiency. Furthermore, in this embodiment, it is not necessary to drop an organic solvent containing a dissolved triplet sensitizer and organic light-emitting material onto the substrate and allow it to volatilize, as is done in conventional methods. In other words, since there is no need to use an organic solvent, the environmental burden in the manufacturing of photo-upconversion organic films can be reduced.

[0065] In this embodiment, a cooling rate for gradually decreasing the temperature of the powder precursor 111 is predetermined in relation to the temperature difference ΔT (or temperature difference ΔT'), and the cooling rate is increased as the temperature difference ΔT (or temperature difference ΔT') increases. This allows for proper induction of crystallization of the molten powder precursor 111, enabling the production of higher quality photo-upconversion organic films.

[0066] In this embodiment, the pressing step (step S2) involves using the depressurization mechanism 15 to reduce the pressure of the environment in which the precursor holding unit 11 is installed, thereby pressing the powder precursor 111. This suppresses the inclusion of air bubbles in the photo-upconversion organic film during the temperature control step, enabling the production of higher-quality photo-upconversion organic films.

[0067] In this embodiment, the crystal of the organic light-emitting material has uniaxial orientation. Therefore, as described above, when crystal growth is performed while generating a temperature gradient along the X direction in the powder precursor 111, crystals with orientation along the X direction can be formed.

[0068] The organic light-emitting material contains an oxazole derivative, and the 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 becomes easy to manufacture a high-quality light up-conversion organic film with high light up-conversion efficiency.

[0069] Further, the organic film manufacturing apparatus 10 of the present embodiment includes a precursor holding portion 11, a pair of sandwiching portions 12A and 12B, a pressing mechanism 14, and a first heating mechanism 13. The precursor holding portion 11 has a holding space 114 with a predetermined height, and holds the powder precursor 111 containing a triplet sensitizer and an organic light-emitting material in the holding space 114. The pair of sandwiching portions 12A and 12B (the first sandwiching portion 12A and the second sandwiching portion 12B) sandwich the precursor holding portion 11 in the height direction (Z direction). The pressing mechanism 14 presses the pair of sandwiching portions 12A and 12B in a direction approaching each other. The first heating mechanism 13 generates a temperature gradient along the X direction by heating the first temperature, which is the temperature of the -X side end portion of the powder precursor 111, and the second temperature, which is the temperature of the +X side end portion, to different temperatures. Then, the powder precursor 111 is heated to above the melting point T of the organic light-emitting material melt(PPO) After heating to the 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) until less than.

[0070] With such an organic film manufacturing apparatus 10, a light up-conversion organic film can be manufactured by the manufacturing method as described above. That is, the first heating mechanism 13 solidifies the melting point T in order from the +X side of the molten powder precursor 111 solid(PPO)It can be cooled to below a certain temperature, and a photo-upconversion organic film with crystal growth along the X direction can be manufactured. This makes it possible to manufacture a photo-upconversion organic film of good quality with high photo-upconversion efficiency. Furthermore, since organic solvents are not required, the environmental impact of the production of photo-upconversion organic films can be reduced.

[0071] In the organic film manufacturing apparatus 10 of this embodiment, the first heating mechanism 13 includes a first heating section 131 provided at the -X side ends of a pair of clamping sections 12A and 12B, a second heating section 132 provided at the +X side ends, and a cooling section 133 connected to the +X side ends. By controlling the heating temperatures of the first heating section 131 and the second heating section 132, a temperature gradient along the X direction can be created in the pair of clamping sections 12A and 12B. On the other hand, with only the first heating section 131 and the second heating section 132, an excessive amount of heat flows from the high-temperature side (-X) to the low-temperature side (+X), making it difficult to properly control the temperature difference ΔT. In contrast, by providing a cooling section 133, the temperature difference ΔT (and temperature difference ΔT') can be properly controlled.

[0072] The first heating section 131 is composed of a first rod heater 131A embedded in the -X side end of the first clamping section 12A, and a first rod heater 131B embedded in the -X side end of the second clamping section 12B. Similarly, the second heating section 132 is composed of a second rod heater 132A embedded in the +X side end of the first clamping section 12A, and a second rod heater 132B embedded in the +X side end of the second clamping section 12B. This makes it possible to maintain the same temperature gradient in both the first clamping section 12A and the second clamping section 12B. In other words, it is possible to suppress the inconvenience of creating a temperature difference in the Z direction of the powder precursor 111, and to generate a temperature gradient along only the X direction.

[0073] In this embodiment, the precursor holding portion 11 is a pair of glass substrates 112A and 112B spaced apart in the Z direction via a spacer 113, and the gap between the pair of glass substrates 112A and 112B forms a holding space 114. The precursor holding portion 11 and an O-ring 122 that absorbs stress in the Z direction are provided between the pair of clamping portions 12A and 12B. The gap between the pair of glass substrates 112A and 112B via the spacer 113 allows the powder precursor 111 to be housed in a holding space 114 with a uniform thickness in the Z direction, enabling the production of an optical upconversion organic film of uniform thickness.

[0074] In this embodiment, the depressurization mechanism 15 has a vacuum chamber 151, and a precursor holding part 11, a pair of clamping parts 12A and 12B, a pressing mechanism 14, and a first heating mechanism 13 are housed inside the vacuum chamber 151, and the vacuum is reduced by a vacuum pump 152. This allows air to escape when the powder precursor 111 is pressed by the pressing mechanism 14. Therefore, it is possible to manufacture a photo-upconversion organic film with suppressed air bubble inclusion.

[0075] In this embodiment, the thermal insulation material 135 further comprises a pair of clamping portions 12A and 12B that are sandwiched in the Z direction. This suppresses the outflow of heat from the pair of clamping portions 12A and 12B, making it easier to maintain a constant temperature difference ΔT between the -X side end and the +X side end of the pair of clamping portions 12A and 12B. In particular, the insulating material 135 is provided so as to cover the position that overlaps with the precursor holding portion 11 in the Z direction. This makes it possible to properly maintain the temperature gradient of the precursor holding portion 11 along the X direction.

[0076] [Second Embodiment] Next, a second embodiment will be described. In the first embodiment described above, the precursor holding portion 11 is held by a pair of clamping portions 12A and 12B that are heated by the first heating mechanism 13 to create a temperature gradient, and the heating temperature by the first heating mechanism 13 is lowered at a constant rate. In contrast, the second embodiment differs from the first embodiment in that the precursor holding portion 11 is moved in a heating region having a temperature gradient.

[0077] Figure 7 is a schematic diagram showing the general configuration of the organic film manufacturing apparatus 20 in the second embodiment. The organic film manufacturing apparatus 20 of this embodiment includes a precursor holding unit 21, a pair of guide plates (first guide plate 22A, second guide plate 22B), a second heating mechanism 23, a moving mechanism 24, a pressure reduction mechanism 25, and a control controller 26.

[0078] The precursor holding section 21 is identical to the precursor holding section 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. In the first embodiment, the organic film manufacturing apparatus 10 is a batch process type for manufacturing a single-chip optical upconversion organic film. On the other hand, in the second embodiment, the organic film manufacturing apparatus 20 is a continuous process type capable of continuously manufacturing optical upconversion organic films that are longitudinal in the X direction. For this reason, the length in the X direction may be longer than that of the precursor holding section 11 of the first embodiment.

[0079] The first guide plate 22A and the second guide plate 22B function as a pair of guides that guide the movement of the precursor holding portion 21 in the X direction. In this embodiment, the first guide plate 22A and the second guide plate 22B are spaced a certain distance apart with respect to the Z direction, and their opposing surfaces are parallel to the XY plane. The precursor holding portion 21 is pressed in the Z direction by being sandwiched between the first guide plate 22A and the second guide plate 22B in the Z direction. In other words, in this embodiment, the pair of first guide plates 22A and second guide plate 22B function as pressing portions.

[0080] The second heating mechanism 23 generates a temperature gradient along the X direction on the first guide plate 22A and the second guide plate 22B. For example, the second heating mechanism 23 consists of multiple rod heaters 231 embedded in the first guide plate 22A and the second guide plate 22B at regular intervals along the X direction, and each is individually controlled. By individually controlling the temperature of each rod heater 231, a temperature gradient is generated on the pair of guide plates 22A and 22B along the X direction.

[0081] More specifically, the second heating mechanism 23 generates a temperature gradient along the X direction of the pair of guide plates 22A and 22B, consisting of a low temperature region, a high temperature region, and another low temperature region. The temperature in the low temperature region is below the freezing point of the organic light-emitting material. The temperature in the high temperature region is above the melting point of the organic light-emitting material. In this case, the temperatures of the opposing positions of the first guide plate 22A and the second guide plate 22B are controlled to be the same. Here, the temperature gradient is larger in the region transitioning from a high temperature to a low temperature region compared to the region transitioning from a low temperature region to a high temperature region from the -X side to the +X side. Also, in the high temperature region, the temperature is maintained above the melting point of the organic light-emitting material for a certain distance along the X direction. As a result, when the precursor holding unit 11 is moved at a constant speed from the +X side to the -X side, the powder precursor 111 at any position is heated at a predetermined heating rate, maintained at a temperature above the melting point of the organic light-emitting material for a certain period of time, and then cooled at a predetermined cooling rate. Here, the cooling rate is set according to the temperature difference ΔT' between the -X side end and the +X side end of the powder precursor 111 as it moves from a high temperature region to a low temperature region along the X direction. For example, when ΔT' = 10℃, it is set to -3℃ / min. In the above example, the precursor holding unit 21 is moved relative to the -X side at a constant speed, the powder precursor 111 is sequentially heated at a preset heating rate (e.g., 5°C / min), and the powder precursor 111 is cooled at a preset cooling rate (e.g., -3°C / min). Therefore, the temperature of each part is controlled so that the temperature gradient from the high temperature region to the low temperature region is larger in the region from the low temperature region to the high temperature region as you move from the -X side to the +X side. On the other hand, the temperature gradient between the portion where the temperature changes from low to high temperature and the portion where the temperature changes from high to low temperature, moving from the -X side to the +X side, may be made the same. In this case, the speed at which the precursor holding unit 21 is moved from the +X side can be appropriately controlled to perform heating at a preset heating rate and cooling at a preset cooling rate.

[0082] The moving mechanism 24 press-fits the precursor holding section 21, which holds the powder precursor 111, between a pair of guide plates 22A and 22B, and then moves the precursor holding section 21 to the -X side. In this embodiment, the moving mechanism 24 has a pair of guide plates 22A and 22B fixed to it, as shown in Figure 7, and moves the precursor holding part 21 to the -X side, but is not limited to this. Figure 8 is a schematic diagram showing the general configuration of an organic film manufacturing apparatus 20A according to a modified example of the second embodiment. For example, as shown in Figure 8, the pair of guide plates 22A and 22B may be configured to be moved to the +X side by means of, for example, a drive roller.

[0083] The depressurization mechanism 25 is the same as in the first embodiment and consists of, for example, a vacuum chamber and a vacuum pump (not shown), and maintains a depressurized environment for the installation of the precursor holding section 21, a pair of guide plates 22A and 22B, the second heating mechanism 23, and the moving mechanism 24.

[0084] The control controller 26 controls the second heating mechanism 23, the moving mechanism 24, and the depressurization mechanism 25. Although not shown in the diagram, it includes a heating drive circuit that controls each rod heater 231 individually, a moving control circuit that controls the moving mechanism 24, a depressurization control circuit that controls the depressurization mechanism 25, and a processor. The processor outputs control signals to these drive circuits as appropriate. This controls the second heating mechanism 23 to generate a temperature gradient on the pair of guide plates 22A and 22B, causing the precursor holding unit 11 to move relative to the pair of guide plates 22A and 22B.

[0085] Figure 9 is a flowchart showing the method for producing the photo-upconversion organic film according to this embodiment. In this embodiment, as in the first embodiment, step S1 is performed to prepare the powder precursor 111 and hold it in the precursor holding unit 21. The precursor holding unit 21 is also set with respect to the moving mechanism 24.

[0086] Next, the processor controls the second heating mechanism 23 to heat the pair of guide plates 22A and 22B, thereby generating the temperature gradient described above (step S12). Next, the processor controls the moving mechanism 24 to press the precursor holding section 21 between the pair of guide plates 22A and 22B and move it toward the -X side (step S13). As a result, the powder precursor 111 is pressed in the Z direction by a pair of guide plates 22A and 22B. Also, the powder precursor 111 held in the precursor holding section 21 moves toward the -X side. By moving from the low temperature region to the high temperature region on the +X side, the powder precursor 111 is heated at a predetermined heating rate, and its melting point T is reached in the high temperature region. melt(PPO) The powder precursor 111 melts upon heating as described above. Subsequently, as the powder precursor 111 moves from the high-temperature region to the low-temperature region, it is cooled sequentially from the -X side end at a predetermined cooling rate. As a result, similar to the first embodiment, the molten powder precursor 111 crystallizes sequentially along the X direction, which is the direction of the temperature gradient. As a result, a photo-upconversion organic film having crystal orientation along the X direction is manufactured. In this embodiment, the precursor holding portion 21 is continuously moved to the -X side by the moving mechanism 24, thereby enabling the continuous production of photo-upconversion organic films.

[0087] [Effects of this embodiment] In this embodiment, the method for manufacturing a photo-upconversion organic film involves, in step S1, holding a powder precursor 111 containing a triplet sensitizer and an organic light-emitting material in the holding space 114 of the precursor holding unit 21. In step S12, the guide plates 22A and 22B are heated so that a temperature gradient is created along the X direction. Then, in step S13, the precursor holding unit 21 is moved relative to the pair of guide plates 22A and 22B, which are heating members, in the X direction. As a result, in step S13, the powder precursor 111 that was transported to the high-temperature region melts, and the molten powder precursor 111 moves further toward the -X side, gradually reaching the solidification point T from the -X side end. solid(PPO) It is cooled to below a certain temperature. Therefore, as in the first embodiment, it is possible to produce a high-quality photo-upconversion organic film with high photo-upconversion efficiency, which is crystallized along the X direction. Furthermore, in this embodiment, there is no need to use organic solvents, which reduces the environmental impact in the production of photo-upconversion organic films.

[0088] The organic film manufacturing apparatus 20 of this embodiment includes a precursor holding section 21, a pair of guide plates 22A and 22B (guide sections), a second heating mechanism 23, and a moving mechanism 24. Similar to the first embodiment, the precursor holding section 21 has a holding space 114 for holding a powder precursor 111 containing a triplet sensitizer and an organic light-emitting material. The pair of guide plates 22A and 22B press and hold the precursor holding portion 21 in the Z direction, and guide the precursor holding portion 21 so that it can move along the X direction. The second heating mechanism 23 heats a pair of guide plates 22A and 22B to create 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. The moving mechanism 24 moves the precursor holding portion 21 relative to the pair of guide plates 22A and 22B in the X direction.

[0089] With such an organic film manufacturing apparatus 20, a photo-upconversion organic film can be manufactured using the manufacturing method described above. Specifically, the second heating mechanism 23 generates a temperature gradient along the X direction on a pair of guide plates 22A and 22B, and the moving mechanism 24 moves the powder precursor 111 held in the precursor holding section 21 in the X direction. As a result, the powder precursor 111 is melted in the high-temperature range, and the powder precursor 111 is sequentially moved from the -X side to the +X side until its solidification point T solid(PPO) It can be cooled to below a certain temperature, and a photo-upconversion organic film with crystal growth along the X direction can be fabricated. Furthermore, since organic solvents are not required, the environmental impact of the production of photo-upconversion organic films can be reduced.

[0090] [Third Embodiment] Next, a third embodiment will be described. Figure 10 is a schematic diagram showing the general configuration of the organic film manufacturing apparatus 30 in the third embodiment. In the second embodiment described above, a temperature gradient is generated on a pair of guide plates 22A and 22B that constitute the guide section, and the precursor holding section 21 is moved relative to the pair of guide plates 22A and 22B toward the -X side. In contrast, the organic film manufacturing apparatus 30 of the third embodiment includes a precursor holding section 31, a plurality of roller pairs 32, a roller heating mechanism 33, a pressure reduction mechanism 25, and a control controller 36.

[0091] The precursor holding section 31 of this embodiment, like the precursor holding section 21 of the second embodiment, comprises a pair of glass substrates 112A, 112B, a spacer 113, and a powder precursor 111 held in a holding space 114 formed by the pair of glass substrates 112A, 112B. In addition, the precursor holding section 31 of this embodiment comprises a pair of support plates 31A, 31B that sandwich the pair of glass substrates 112A, 112B in the Z direction. These support plates 31A, 31B are preferably made of a material with good thermal conductivity, such as metal.

[0092] Each roller pair 32 is composed of a pair of rollers 321 aligned in the Z direction, and the precursor holding portion 31 is held between these two rollers 321 aligned in the Z direction. By arranging multiple roller pairs 32 along the X direction, the precursor holding portion 31 is held in the XY plane. That is, the rollers 321 on the +Z side of the multiple roller pairs 32 constitute one of the pair of guide portions of the present invention, and the rollers 321 on the -Z side of the multiple roller pairs 32 constitute the other of the pair of guide portions of the present invention. Each roller 321 has a rotation axis parallel to the Y direction, which is perpendicular to the X and Z directions, and is rotated around its axis by a drive source such as a motor. The rotational drive of the rollers 321 transports the precursor holding portion 31, which is held in the XY plane, to the -X side. That is, these roller pairs 32 also function as a moving mechanism of the present invention.

[0093] The roller heating mechanism 33 heats each roller pair 32 independently. That is, the roller heating mechanism 33 functions as the second heating mechanism of the present invention. Note that the pair of rollers 321 arranged in the Z direction that make up one roller pair 32 reach the same temperature. An example of a configuration for heating each roller 321 is to provide a heater on the rotation axis of the roller 321. In this embodiment, the roller heating mechanism 33 heats the pair of rollers 32 located at the -X side end to the solidification point T of the organic light-emitting material. solid(PPO) The temperature is heated to a level below the melting point T of the organic light-emitting material. The roller heating mechanism 33 also sequentially increases the temperature of a predetermined number of roller pairs 32 lined up from the -X side end toward the +X side, and raises the temperature of the Mth (third in the example of Figure 10) roller pair 32 to at least the melting point T of the organic light-emitting material. melt(PPO) The temperature is set to the above. The temperature of a predetermined number of roller pairs 32 lined up on the +X side from this Mth roller pair 32 is sequentially lowered as one moves toward the +X side, and the temperature of the Nth (5th in the example of Figure 10) roller pair 32 is set to the solidification point T of the organic light-emitting material. solid(PPO)The temperature should be less than [a certain value]. Note that in Figure 10, for the sake of simplicity, an example is shown with five roller pairs 32, where the third roller pair 32 becomes hot. In reality, more roller pairs 32 are arranged, and the temperature of each roller pair 32 is controlled more precisely. This makes it possible to move the precursor holding unit 31 so that the powder precursor 111 is heated at a preset heating rate and cooled at a preset cooling rate, similar to the second embodiment.

[0094] As the precursor holding section 31 is transported to the -X side by these multiple roller pairs 32, heat from the roller pairs 32 is transferred to the support plates 31A and 31B of the precursor holding section 31, respectively. As a result, the amount of heat transferred to the pair of support plates 31A and 31B changes depending on the position, and a temperature gradient along the X direction is generated in the precursor holding section 31. In other words, of 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 region corresponding to the roller pair 32 at the -X side end and the Nth roller pair 32 corresponds to the low-temperature region of the second embodiment. Therefore, in this embodiment as well, as in the second embodiment, as the powder precursor 111 is moved to the -X side, the powder precursor 111 at any position in the X direction reaches its freezing point T solid(PPO) From a temperature below the melting point T of the organic light-emitting material at a predetermined heating rate melt(PPO) It melts under controlled temperatures and solidifies at a predetermined cooling rate until it reaches its freezing point T solid(PPO) It is cooled to a temperature below 10. Therefore, the powder precursor 111 is cooled at the aforementioned rate of cooling while having a temperature gradient along the X direction, and crystal growth occurs along the X direction to produce a photo-upconversion organic film.

[0095] The pressure reduction mechanism 25 is the same as in the second embodiment and consists of, for example, a vacuum chamber and a vacuum pump (not shown), and maintains a reduced pressure environment for the installation of the precursor holding section 31, the multiple pairs of rollers 32, and the roller heating mechanism 33.

[0096] The control controller 36 controls the roller pairs 32, the roller heating mechanism 33, and the pressure reduction mechanism 25. Although not shown in the diagram, the control controller 36 includes a heating drive circuit that individually controls the roller heating mechanism 33 of each roller pair 32, a rotation control circuit that rotates the pair of rollers 321 of the roller pair 32, a pressure reduction control circuit that controls the pressure reduction mechanism 25, and a processor. The processor outputs control signals to these drive circuits as needed. This controls the roller heating mechanism 33 to generate a temperature gradient on the precursor holding section 31, which is transported by the roller pair 32, causing the precursor holding section 11 to move in the X direction.

[0097] In the example shown in Figure 10, the precursor holding section 31 is conveyed in the X direction by multiple pairs of rollers 32, but the system is not limited to this, and any configuration that moves the precursor holding section 31 relative to the X direction is acceptable. For example, the multiple pairs of rollers 32 may be configured to move to the +X side relative to the precursor holding section 31 while maintaining their spacing, or the multiple pairs of rollers 32 may be moved to the X side and the precursor holding section 31 may be moved to the -X side.

[0098] Figure 11 is a flowchart showing the method for producing the photo-upconversion organic film according to this embodiment. In this embodiment, an optical upconversion organic film can be manufactured by a method substantially the same as that of the second embodiment. First, step S1 is performed to prepare the powder precursor 111 and hold it in the precursor holding section 31. In this embodiment, a pair of glass substrates 112A and 112B are further sandwiched between a pair of support plates 31A and 31B.

[0099] Next, the processor controls the roller heating mechanism 33 to independently heat each of the multiple roller pairs 32 aligned in the X direction. In other words, as described above, the temperature of each roller pair 32 is independently controlled so that the temperature gradually increases from the roller pair 32 at the -X side end to the Mth roller pair 32 as you move toward the +X side, and the temperature gradually decreases from the Mth to the Nth roller pair as you move toward the +X side (step S22). Next, the processor controls the rotation of each roller pair 32 to transport the precursor holding section 31 from the roller pair 32 at the +X side end toward the -X side (step S23). As a result, the powder precursor 111 is pressed in the Z direction by a pair of rollers 321 aligned in the Z direction. The powder precursor 111 held in the precursor holding section 31 also moves toward the -X side. The precursor holding section 31 is transported from the Nth low-temperature roller pair 32 to the Mth high-temperature roller pair 32, causing the powder precursor 111 to be heated at a predetermined heating rate. Near the Mth roller pair 32, the powder precursor 111 reaches its melting point T melt(PPO) The powder precursor 111 melts upon heating to the above temperature. Subsequently, the powder precursor 111 is moved from the Mth-th roller pair 32 toward the -X side, and is cooled sequentially from the -X side end of the powder precursor 111 at a predetermined cooling rate. As a result, similar to the embodiments described above, the molten powder precursor 111 crystallizes sequentially along the X direction, which is the direction of the temperature gradient. As a result, a photo-upconversion organic film having crystal orientation along the X direction is manufactured. In this embodiment, similar to the second embodiment, the precursor holding portion 31 is continuously moved to the -X side by a plurality of roller pairs 32, thereby enabling the continuous production of photo-upconversion organic films.

[0100] [Effects of this embodiment] In this embodiment, the method for manufacturing a photo-upconversion organic film involves, in step S1, holding a powder precursor 111 containing a triplet sensitizer and an organic light-emitting material in the holding space 114 of the precursor holding unit 21. In step S22, multiple pairs of rollers are heated so that a temperature gradient is created along the X direction. Then, in step S23, the precursor holding unit 31 is moved relative to each other in the X direction using multiple pairs of rollers 32, which are heating members. As a result, in step S23, the powder precursor 111 that was transported to the high-temperature heated roller pair 32 (the Mth roller pair) melts, and the molten powder precursor 111 is further transported to the -X side, gradually reaching the solidification point T from the -X side end. solid(PPO)It is cooled to below a certain temperature. Therefore, as with the first and second embodiments described above, it is possible to produce a high-quality photo-upconversion organic film with high photo-upconversion efficiency, which is crystallized along the X direction. Furthermore, in this embodiment, there is no need to use organic solvents, which reduces the environmental impact in the production of photo-upconversion organic films.

[0101] The organic film manufacturing apparatus 30 of this embodiment includes a precursor holding section 31, a plurality of roller pairs 32 (guide sections), and a roller heating mechanism 33 (second heating mechanism). Similar to the first and second embodiments, the precursor holding section 31 has a pair of glass substrates 112A, 112B and a spacer 113 that constitute a holding space 114 for holding a powder precursor 111 containing a triplet sensitizer and an organic light-emitting material, and further comprises a pair of support plates 31A, 31B that sandwich the pair of glass substrates 112A, 112B. Multiple pairs of rollers 32 function as guides of the present invention and have rollers 321 that rotate around a rotation axis parallel to the Y direction and perpendicular to the Z and X directions, with pairs of rollers 321 forming a pair in the Z direction. The roller heating mechanism 33 individually controls the temperature of each roller pair 32 aligned in the X direction so that the roller pair 32 with a high temperature range (the Mth roller pair 32) is aligned in the X direction, followed by the roller pair 32 with a low temperature range (the roller pair 32 at the X-side end).

[0102] With such an organic film manufacturing apparatus 30, a photo-upconversion organic film can be manufactured using the manufacturing method described above. Specifically, the roller heating mechanism 33 controls the temperature of multiple pairs of rollers 32 aligned in the X direction to create a temperature gradient along the X direction. In addition, the rotational drive of each roller 321 of the pairs of rollers 32 moves the precursor holding section 31, which holds the powder precursor 111, in the X direction. As a result, the powder precursor 111 is melted at a high temperature, and the powder precursor 111 is sequentially heated from the -X side to the +X side until its solidification point T solid(PPO) It can be cooled to below a certain temperature, and a photo-upconversion organic film with crystal growth along the X direction can be fabricated. Furthermore, since organic solvents are not required, the environmental impact of the production of photo-upconversion organic films can be reduced.

[0103] [Fourth Embodiment] This embodiment relates to an organic film for optical upconversion. Optical upconversion is sometimes referred to as photon upconversion.

[0104] The photo-upconversion organic film of this embodiment comprises a triplet sensitizer and an organic light-emitting material, the organic light-emitting material having ultraviolet light emission properties. The photo-upconversion organic film of this embodiment is a crystalline film.

[0105] In the photo-upconversion organic film of this embodiment, the triplet sensitizer absorbs excitation light and becomes excited, generating triplet excitons 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), collide with each other, and undergo 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 photo-upconversion organic film of this embodiment can emit light with a shorter wavelength than the light absorbed by the triplet sensitizer (upconversion).

[0106] Figure 12 shows the upconversion mechanism in the photo-upconversion organic film of this embodiment. As shown in Figure 12, the lowest excited triplet state of the triplet sensitizer is generated by intersystem crossing from the lowest excited singlet state excited by absorbing excitation light (e.g., visible photons), triplet-triplet energy transfer (TET) occurs to the organic light-emitting material, generating the lowest excited triplet state of the organic light-emitting material, and when two organic light-emitting material molecules in the triplet state collide, TTA generates the lowest excited singlet state of the organic light-emitting material. Light emission (e.g., ultraviolet photons) is generated from the lowest excited singlet state of the organic light-emitting material, which is at a higher energy level than the lowest excited singlet state of the triplet sensitizer. In Figure 12, S is the ground state of the sensitizer. 1 S * This is the lowest excited singlet state of the sensitizer. 3 S * A is the lowest excited triplet state of the sensitizer, A is the ground state of the luminescent material. 1 A * This is the lowest excited singlet state of the luminescent material. 3 A * Φ is the lowest excited triplet state of the luminescent material. ISC This is the intersystem crossing quantum efficiency of the sensitizer from the lowest excitation singlet to the lowest excitation triplet, Φ F(S) This is the emission quantum efficiency from the lowest excitation singlet of the sensitizer, Φ F(A) These figures represent the quantum emission efficiency from the lowest excited singlet state of the luminescent material.

[0107] In the photo-upconversion organic film of this embodiment, the triplet sensitizer is a material that absorbs excitation light and generates excited triplet excitons. In the photo-upconversion organic film of this embodiment, the organic light-emitting material is preferably a material that emits light having a maximum peak in a wavelength region shorter than the longest wavelength maximum peak wavelength in the absorption spectrum of the triplet sensitizer, and having a maximum peak in a wavelength region of 400 nm or less (preferably 315 nm or more and 400 nm or less). Here, the maximum peak wavelength of the triplet sensitizer is the maximum peak wavelength in the absorption spectrum of the triplet sensitizer alone, and the maximum peak wavelength of the organic light-emitting material is the maximum peak wavelength in the emission spectrum of the organic light-emitting material alone.

[0108] The optical upconversion organic film according to this embodiment can upconvert visible light to ultraviolet light. In this specification, ultraviolet light is light in the wavelength range of 315 nm to 400 nm.

[0109] In the photo-upconversion organic film according to this embodiment, it is preferable that the triplet sensitizer is contained in a dispersed state within a crystalline film of the organic light-emitting material. The dispersion of the triplet sensitizer within a film of the crystalline organic light-emitting material facilitates triplet-triplet energy transfer from the triplet sensitizer to the organic light-emitting material.

[0110] In the photo-upconversion organic film of this 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 even more preferably 1:10000 to 1:50000. The number of moles M of the triplet sensitizer in the photo-upconversion organic film of this embodiment. S The number of moles of organic light-emitting material M A Ratio M A / M S However, it is preferable that it be between 1000 and 100000. Molar ratio M A / M S It is more preferably 5000 or more, and even more preferably 10000 or more. Molar ratio M A / M S It is more preferable that it be 80,000 or less, and even more preferable that it be 50,000 or less. Ratio M A / M S However, having a value of 1000 or higher makes it easier to improve the upconversion quantum efficiency and lower the excitation threshold intensity. Ratio M A / MS However, by keeping it below 100,000, the decrease in upconversion quantum efficiency caused by (i) and (ii) below can be prevented. (i) Excessive triplet sensitizers reduce the lifetime of the lowest excited triplet state. (ii) The photo-upconversion emission is reabsorbed by the triplet sensitizer itself.

[0111] In this specification, for example, a numerical range expressed using "AA~BB" means a range that includes the numerical value AA, which is written before the "~" in "AA~BB", as the lower limit, and the numerical value BB, which is written after the "~" in "AA~BB", as the upper limit.

[0112] The photo-upconversion organic film of this embodiment preferably does not contain polymer compounds. Polymer compounds are, for example, compounds with a molecular weight of 10,000 or more. Examples of polymer compounds include polymers. It is also preferable that the triplet sensitizer and the organic light-emitting material are not polymer compounds.

[0113] The total content of the triplet sensitizer and the organic light-emitting material in the photo-upconversion organic film of this embodiment is preferably 90% by mass or more, more preferably 95% by mass or more, and even more preferably 99% by mass or more. The photo-upconversion organic film of this embodiment preferably consists of only two components: a triplet sensitizer and an organic light-emitting material.

[0114] In the photo-upconversion organic film according to this embodiment, the content of organic solvent is preferably 1% by mass or less, more preferably 0.1% by mass or less, and even more preferably 0.01% by mass or less. It is preferable that the photo-upconversion organic film according to this embodiment does not contain organic solvents. Because organic solvents are volatile, flammable, and biotoxic, the lower the organic solvent content in the film, the better the safety and stability of the photo-upconversion organic film, making it easier to apply to environmentally conscious applications.

[0115] In the photo-upconversion organic film according to this embodiment, the excitation threshold intensity is 50 mW / cm². 2 Preferably, it is 45 mW / cm² 2 More preferably, the following is true: 30 mW / cm² 2 It is even more preferable that the following conditions are met: 25 mW / cm² 2 The following is even more preferable:

[0116] (Organic luminescent materials) In the photo-upconversion organic film of this embodiment, the fluorescence quantum yield of the organic light-emitting material is preferably 40% or more, and more preferably 50% or more. A fluorescence quantum yield of 40% or more in the organic light-emitting material makes it easier to increase the upconversion quantum efficiency.

[0117] In the photo-upconversion organic film of this embodiment, it is preferable that the crystals of the organic light-emitting material have uniaxial orientation. The uniaxial orientation of the crystals can be confirmed by observation with a polarizing microscope, as described in the examples below. The uniaxial orientation of the crystals of the organic light-emitting material facilitates triplet-triplet energy transfer from the triplet sensitizer to the organic light-emitting material, and triplet-triplet energy transfer between organic light-emitting materials.

[0118] In the photo-upconversion organic film of this embodiment, the melting point of the organic light-emitting material is preferably 120°C or lower, more preferably 100°C or lower, and even more preferably 80°C or lower. Having a melting point of 120°C or lower for the organic light-emitting material facilitates the formation of the photo-upconversion organic film in the manufacturing method according to the above embodiment.

[0119] In the photo-upconversion organic film of this embodiment, it is preferable that the organic light-emitting material does not contain metal atoms in its molecule. By using an organic light-emitting material that does not contain metal atoms, it is possible to avoid environmental pollution caused by metals during the manufacturing and disposal of the photo-upconversion organic film.

[0120] In the photo-upconversion organic film of this embodiment, it is preferable that the organic light-emitting material contains only hydrogen atoms, carbon atoms, oxygen atoms, and nitrogen atoms in its molecule.

[0121] In the photo-upconversion organic film of this embodiment, it is also preferable that the organic light-emitting material does not contain a fused ring skeleton containing three or more benzene rings in its molecule.

[0122] In the photo-upconversion organic film of this embodiment, the organic light-emitting material preferably contains at least one compound selected from the group consisting of, for example, oxazole derivatives, thiazole derivatives, fluorene derivatives, dibenzofuran derivatives, and dibenzothiophene derivatives.

[0123] In the photo-upconversion organic film of this embodiment, it is preferable that the organic light-emitting material includes an oxazole derivative.

[0124] In the photo-upconversion organic film of this embodiment, the organic light-emitting material preferably contains a compound represented by the following general formula (1).

[0125] [ka]

[0126] In the above general formula (1), R 11 , R 12 and R 13 Each of these is independently a hydrogen atom or a substituent. In the above general formula (1), R as a substituent 11 , R 12 and R 13 Each of these is preferably independently a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, a substituted or unsubstituted aryl group having 6 to 50 ring-forming carbon atoms, or a substituted or unsubstituted heterocyclic group having 5 to 50 ring-forming atoms.

[0127] In the above general formula (1), R 11and R 12 Each of these groups is preferably a substituted or unsubstituted aryl group having 6 to 50 ring-forming carbon atoms, more preferably a substituted or unsubstituted aryl group having 6 to 18 ring-forming carbon atoms, and even more preferably a substituted or unsubstituted aryl group having 6 to 14 ring-forming carbon atoms.

[0128] In the above general formula (1), R 13 It is preferable that it be a hydrogen atom.

[0129] In the above general formula (1), R 11 and R 12 It is preferable that these are the same group.

[0130] Examples of substituted or unsubstituted ring-forming aryl groups with 6 to 50 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-naphthacenyl, 2-naphthacenyl, 9-naphthacenyl, 1-pyrenyl, 2-pyrenyl, 4-pyrenyl, 2-biphenylyl, 3-biphenylyl, 4-biphenylyl, and p-ter Examples include phenyl-4-yl group, p-terphenyl-3-yl group, p-terphenyl-2-yl group, m-terphenyl-4-yl group, m-terphenyl-3-yl group, m-terphenyl-2-yl group, o-tolyl group, m-tolyl group, p-tolyl group, pt-butylphenyl group, p-(2-phenylpropyl)phenyl group, 3-methyl-2-naphthyl group, 4-methyl-1-naphthyl group, 4-methyl-1-anthryl group, 4'-methylbiphenylyl group, and 4"-t-butyl-p-terphenyl-4-yl group.

[0131] Examples of heterocyclic groups with 5 to 50 substituted or unsubstituted ring-forming atoms include 1-pyrrolyl group, 2-pyrrolyl group, 3-pyrrolyl group, pyrazinyl group, 2-pyridinyl group, 3-pyridinyl group, 4-pyridinyl group, 1-indolyl group, 2-indolyl group, 3-indolyl group, 4-indolyl group, 5-indolyl group, 6-indolyl group, 7-indolyl group, 1-isoindolyl group, 2-isoindolyl group, 3-isoindolyl group, 4-isoindolyl group, 5-isoindolyl group, 6-isoindolyl group, 7-isoindolyl group, 2-furyl group, 3-furyl group, 2-be Isofuranyl group, 3-benzofuranyl group, 4-benzofuranyl group, 5-benzofuranyl group, 6-benzofuranyl group, 7-benzofuranyl group, 1-isobenzofuranyl group, 3-isobenzofuranyl group, 4-isobenzofuranyl group, 5-isobenzofuranyl group, 6-isobenzofuranyl group, 7-isobenzofuranyl group, quinolyl group, 3-quinolyl group, 4-quinolyl group, 5-quinolyl group, 6-quinolyl group, 7-quinolyl group, 8-quinolyl group, 1-isoquinolyl group, 3-isoquinolyl group, 4-isoquinolyl group, 5-isoquinolyl group, 6-isoquinolyl group, 7-iso Quinolyl group, 8-isoquinolyl group, 2-quinoxalinyl group, 5-quinoxalinyl group, 6-quinoxalinyl group, 1-carbazolyl group, 2-carbazolyl group, 3-carbazolyl group, 4-carbazolyl group, 9-carbazolyl group, 1-phenanthridinyl group, 2-phenanthridinyl group, 3-phenanthridinyl group, 4-phenanthridinyl group, 6-phenanthridinyl group, 7-phenanthridinyl group, 8-phenanthridinyl group, 9-phenanthridinyl group, 10-phenanthridinyl group, 1-acridinyl group, 2-acridinyl group, 3-acridinyl group, 4- Acridinyl group, 9-acridinyl group, 1,7-phenanthroline-2-yl group, 1,7-phenanthroline-3-yl group, 1,7-phenanthroline-4-yl group, 1,7-phenanthroline-5-yl group, 1,7-phenanthroline-6-yl group, 1,7-phenanthroline-8-yl group, 1,7-phenanthroline-9-yl group, 1,7-phenanthroline-10-yl group, 1,8-phenanthroline-2-yl group, 1,8-phenanthroline-3-yl group, 1,8-phenanthroline-4-yl group, 1,8-phenanthroline-5-yl group, 1,8-phenanthroline-6-yl group, 1,8-phenanthroline-7-yl group, 1,8-phenanthroline-9-yl group, 1,8-phenanthroline-10-yl group, 1,9-phenanthroline-2-yl group, 1,9-phenanthroline-3-yl group, 1,9-phenanthroline-4-yl group, 1,9-phenanthroline-5-yl group, 1,9-phenanthroline-6-yl group, 1,9-phenanthroline-7-yl group group, 1,9-phenanthroline-8-yl group, 1,9-phenanthroline-10-yl group, 1,10-phenanthroline-2-yl group, 1,10-phenanthroline-3-yl group, 1,10-phenanthroline-4-yl group, 1,10-phenanthroline-5-yl group, 2,9-phenanthroline-1-yl group, 2,9-phenanthroline-3-yl group, 2,9-phenanthroline-4-yl group, 2,9-phenanth Lorin-5-yl group, 2,9-phenanthrorin-6-yl group, 2,9-phenanthrorin-7-yl group, 2,9-phenanthrorin-8-yl group, 2,9-phenanthrorin-10-yl group, 2,8-phenanthrorin-1-yl group, 2,8-phenanthrorin-3-yl group, 2,8-phenanthrorin-4-yl group, 2,8-phenanthrorin-5-yl group, 2,8-phenanthrorin-6-yl group, 2,8-ph Phenanceroline-7-yl group, 2,8-phenanceroline-9-yl group, 2,8-phenanceroline-10-yl group, 2,7-phenanceroline-1-yl group, 2,7-phenanceroline-3-yl group, 2,7-phenanceroline-4-yl group, 2,7-phenanceroline-5-yl group, 2,7-phenanceroline-6-yl group, 2,7-phenanceroline-8-yl group, 2,7-phenanceroline-9-yl group, 2,7-Phenanthroline-10-yl group, 1-phenazinyl group, 2-phenazinyl group, 1-phenothiazinyl group, 2-phenothiazinyl group, 3-phenothiazinyl group, 4-phenothiazinyl group, 10-phenothiazinyl group, 1-phenoxazinyl group, 2-phenoxazinyl group, 3-phenoxazinyl group, 4-phenoxazinyl group, 10-phenoxazinyl group, 2-oxazolyl group, 4-oxazolyl group, 5-oxazolyl group, 2-oxadiazolyl group, 5-oxadiazolyl group, 3-flazanyl group, 2-thienyl group, 3-thienyl group, 2-methylpyrrole-1-yl group, 2-methylpyrrole-3-yl group, Examples include 2-methylpyrrole-4-yl group, 2-methylpyrrole-5-yl group, 3-methylpyrrole-1-yl group, 3-methylpyrrole-2-yl group, 3-methylpyrrole-4-yl group, 3-methylpyrrole-5-yl group, 2-t-butylpyrrole-4-yl group, 3-(2-phenylpropyl)pyrrole-1-yl group, 2-methyl-1-indolly group, 4-methyl-1-indolly group, 2-methyl-3-indolly group, 4-methyl-3-indolly group, 2-t-butyl1-indolly group, 4-t-butyl1-indolly group, 2-t-butyl3-indolly group, and 4-t-butyl3-indolly group.

[0132] Examples of substituted or unsubstituted C1-C50 alkyl groups include methyl, ethyl, propyl, isopropyl, n-butyl, s-butyl, isobutyl, t-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, hydroxymethyl, 1-hydroxyethyl, 2-hydroxyethyl, 2-hydroxyisobutyl, 1,2-dihydroxyethyl, 1,3-dihydroxyisopropyl, and 2,3-dihydroxy-t-butyl groups. Group, 1,2,3-trihydroxypropyl group, chloromethyl group, 1-chloroethyl group, 2-chloroethyl group, 2-chloroisobutyl group, 1,2-dichloroethyl group, 1,3-dichloroisopropyl group, 2,3-dichloro-t-butyl group, 1,2,3-trichloropropyl group, bromomethyl group, 1-bromoethyl group, 2-bromoethyl group, 2-bromoisobutyl group, 1,2-dibromoethyl group, 1,3-dibromoisopropyl group, 2,3-dibromo-t-butyl group, 1,2,3- Tribromopropyl group, iodomethyl group, 1-iodoethyl group, 2-iodoethyl group, 2-iodoisobutyl group, 1,2-diiodoethyl group, 1,3-diiodoisopropyl group, 2,3-diiodo-t-butyl group, 1,2,3-triiodopropyl group, aminomethyl group, 1-aminoethyl group, 2-aminoethyl group, 2-aminoisobutyl group, 1,2-diaminoethyl group, 1,3-diaminoisopropyl group, 2,3-diamino-t-butyl group, 1,2,3-triaminopropyl group Examples include cyanomethyl group, 1-cyanoethyl group, 2-cyanoethyl group, 2-cyanoisobutyl group, 1,2-dicyanoethyl group, 1,3-dicyanoisopropyl group, 2,3-dicyano-t-butyl group, 1,2,3-tricyanopropyl group, nitromethyl group, 1-nitroethyl group, 2-nitroethyl group, 2-nitroisobutyl group, 1,2-dinitroethyl group, 1,3-dinitroisopropyl group, 2,3-dinitro-t-butyl group, and 1,2,3-trinitropropyl group.

[0133] In the photo-upconversion organic film of this embodiment, for example, compounds represented by the following formulas (11) to (13) can be used as organic light-emitting materials. The compounds represented by the following formulas (11) to (13) are relatively easy to obtain.

[0134]

Chem.

[0135] The melting point of the compound represented by the formula (11) is 69 °C, and the fluorescence quantum yield Φ F(A) is 79%. The compound represented by the formula (11) may be abbreviated as PPO. The melting point of the compound represented by the formula (12) is 88 °C, and the fluorescence quantum yield Φ F(A) is 46%. The compound represented by the formula (12) may be abbreviated as PPF. The melting point of the compound represented by the formula (13) is 105 °C, and the fluorescence quantum yield Φ F(A) is 37%. The compound represented by the formula (13) may be abbreviated as α-NPO.

[0136] In the light up-conversion organic film of the present embodiment, the organic light-emitting material is preferably the compound (2,5-diphenyloxazole) represented by the formula (11).

[0137] (Triplet sensitizer) In the photo-upconversion organic film of this embodiment, the triplet sensitizer is preferably a compound having an absorption maximum wavelength within the wavelength range of sunlight. Typically, the triplet sensitizer used has an absorption maximum wavelength in the range of 200 nm to 1000 nm. Preferably, the triplet sensitizer has an absorption maximum wavelength in the range of 400 nm to 700 nm. By having the absorption maximum wavelength of the triplet sensitizer within this range, it is possible to convert relatively long wavelengths of light, which are not used by general photo-to-secondary energy conversion elements (elements that convert light to secondary energy) such as solar cells and hydrogen generation photocatalysts, into relatively short wavelengths of light (for example, less than 400 nm) that are used by general photo-to-secondary energy conversion elements. Therefore, the photo-upconversion organic film of this embodiment makes it possible to effectively utilize a wide range of wavelengths of light contained in sunlight in photo-to-secondary energy conversion elements. Furthermore, in the photo-upconversion organic film of this embodiment, in order to effectively utilize light with wavelengths in the blue, violet, and ultraviolet regions, the triplet sensitizer may be a compound having an absorption maximum wavelength within the range of 250 nm to 499 nm.

[0138] As a triplet sensitizer, any compound that has light absorption in the range from the ultraviolet to the infrared region can be used, even molecular species that have not been previously called dyes. Examples of triplet sensitizers include acenaphthene derivatives, acetophenone derivatives, anthracene derivatives, diphenylacetylene derivatives, acridan derivatives, acridine derivatives, acridone derivatives, thioacridone derivatives, angelicin derivatives, anthracene derivatives, anthraquinone derivatives, azafluorene derivatives, azulene derivatives, benzyl derivatives, carbazole derivatives, coronene derivatives, sumanene derivatives, biphenylene derivatives, fluorene derivatives, perylene derivatives, phenanthrene derivatives, phenanthroline derivatives, phenazine derivatives, benzophenone derivatives, pyrene derivatives, benzoquinone derivatives, biacetyl derivatives, biantranyl derivatives, fullerene derivatives, graphene derivatives, carotene derivatives, chlorophyll derivatives, chrysene derivatives, sinnoline derivatives, coumarin derivatives, curcumin derivatives, dansylamide derivatives, flavone derivatives, fluorenone derivatives, fluorescein derivatives, helicene derivatives, indene derivatives, lumichrome derivatives, lumiflavin derivatives, oxadiazole derivatives, perifrantene derivatives, and 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, pyromethene derivatives, pyridyl ketone derivatives, phenyl ketone derivatives, pyridyl ketone derivatives, thienyl ketone derivatives, furanyl ketone derivatives, quinazoline derivatives, quinoline derivatives, quinoxaline derivatives, retinal derivatives, Retinol derivatives, rhodamine derivatives, riboflavin derivatives, rubrene derivatives, squaline derivatives, stilbene derivatives, tetracene derivatives, pentacene derivatives, anthraquinone derivatives, tetracenequinone derivatives, pentacenequinone derivatives, thiophosgene derivatives, indigo derivatives, thioinzogo derivatives, thioxanthene derivatives, thymine derivatives, triphenylene derivatives, triphenylmethane derivatives, triaryl derivatives, tryptophan derivatives, uracil derivatives, xanthene derivatives, ferrocene derivatives, azulene derivatives,Examples include biacetyl derivatives, terphenyl derivatives, terfuran derivatives, terthiophene derivatives, oligoaryl derivatives, fullerene derivatives, conjugated polyene derivatives, group 14 element condensed polycyclic aromatic compound derivatives, and condensed polycyclic heteroaromatic compound derivatives. Triplet sensitizers are not limited to these.

[0139] Triplet sensitizers include, specifically, metal porphyrins (metal complexes of porphyrins); metal tetraazaporphyrins (metal complexes of tetraazaporphyrins); metal phthalocyanines (metal complexes of phthalocyanines); iodine derivatives of 3,5-dimethylborondipyrrometene; iodine derivatives of 3,5-dimethyl-8-phenylborondipyrrometene, and other borondipyrrometenes; Schiff base metal complexes such as salen metal complexes; metal bipyridine complexes such as rubidium-bipyridine complexes and iridium-phenanthroline complexes; metal phenanthroline complexes; naphthalenediimides such as N-alkylnaphthalenediimides; N Examples include acridones such as 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'-biantril; oligoaryls such as bifuran, bithiophene, and bis(benzoxazolyl)thiophene; and condensed polycyclic heteroaromatic compounds such as chrysene, phenanthrene, or their derivatives. Triplet sensitizers are not limited to these.

[0140] In the photo-upconversion organic film of this embodiment, it is preferable that the triplet sensitizer does not contain metal atoms in its molecule. By using a triplet sensitizer that does not contain metal atoms, it is possible to avoid environmental pollution caused by metals during the manufacturing and disposal of the photo-upconversion organic film.

[0141] In the photo-upconversion organic film of this embodiment, it is preferable that the triplet sensitizer contains only hydrogen atoms, carbon atoms, oxygen atoms, and nitrogen atoms in its molecule.

[0142] In the photo-upconversion organic film of this embodiment, the triplet sensitizer preferably contains a coumarin derivative.

[0143] In the photo-upconversion organic film of this embodiment, it is preferable that the triplet sensitizer is a coumarin derivative and the organic light-emitting material is an oxazole derivative. By combining such a triplet sensitizer and organic light-emitting material, the overlap integral between the emission spectrum of the triplet sensitizer and the absorption spectrum of the organic light-emitting material becomes large, and as a result, triplet-triplet energy transfer from the triplet sensitizer to the organic light-emitting material is facilitated.

[0144] In the photo-upconversion organic film of this embodiment, the triplet sensitizer preferably contains a compound having at least one skeleton represented by the following general formula (CMR3) in its molecule.

[0145] [ka]

[0146] In the above general formula (CMR3), R 31 ~R 36 Each of these is independently a hydrogen atom or a substituent. 31 ~R 36 One or more pairs of adjacent elements from among them either bond to each other to form a substituted or unsubstituted monoring, or bond to each other to form a substituted or unsubstituted fused ring, or do not bond to each other. In the general formula (CMR3), R 31 ~R 36 Preferably, at least one of them is a substituent, R 31 , R 32 and R 37 It is more preferable that at least one of them is a substituent. For example, R 37When it is an electron-donating group, it tends to exhibit strong light absorption and emission. Also, when at least one of R 31 and R 32 is a substituent, it tends to greatly change the absorption wavelength and emission wavelength. When at least one of R 31 and R 32 is an electron-withdrawing group, it tends to increase the emission luminance. In the general formula (CMR3), R 31 ~R 36 are each independently a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, a substituted or unsubstituted aryl group having 6 to 50 ring-forming carbon atoms, a substituted or unsubstituted heterocyclic group having 5 to 50 ring-forming 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-forming carbon atoms, or a substituted or unsubstituted heterocyclic group having 5 to 50 ring-forming atoms. In the general formula (CMR3), the substituted or unsubstituted heterocyclic group having 5 to 50 ring-forming atoms as R 31 ~R 40 is also preferably, for example, a substituted or unsubstituted benzimidazole group or a substituted or unsubstituted benzothiazole group.

[0147] In the light up-conversion organic film of this embodiment, the triplet sensitizer preferably contains a compound having at least two skeletons represented by the general formula (CMR3) in the molecule. When the triplet sensitizer has at least two skeletons represented by the general formula (CMR3) in the molecule, R 31 ~R 36At least one of them is a single bond that binds to a skeleton represented by another general formula (CMR3), or a linking group that connects to a skeleton represented by another general formula (CMR3).

[0148] In the photo - up - conversion organic film of the present embodiment, it is preferable that the triplet sensitizer contains a compound represented by the following general formula (CMR31).

[0149]

Chemical formula

[0150] In the general formula (CMR31), L3 is a linking group, and R 32 ~R 36 are each independently synonymous with R 32 ~R 36 in the general formula (CMR3), and a plurality of R 32 are the same as or different from each other, a plurality of R 33 are the same as or different from each other, a plurality of R 34 are the same as or different from each other, a plurality of R 35 are the same as or different from each other, a plurality of 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 - forming carbon atoms, or a substituted or unsubstituted divalent heterocyclic group having 5 to 50 ring - forming 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 thienylene group.

[0151] In the photo - up - conversion organic film of the present embodiment, the compound represented by the general formula (CMR31) is preferably a compound represented by the following general formula (CMR32).

[0152]

Chemical formula

[0153] In the general formula (CMR32), R 32 ~R 36 are each independently the same as R 32 ~R 36 in the general formula (CMR31).

[0154] In the photo - up - conversion organic film of the present embodiment, the coumarin derivative as a triplet sensitizer preferably has at least one group represented by -N(R 37 )(R 38 ).

[0155] In the photo - up - conversion organic film of the present embodiment, the compound represented by the general formula (CMR31) and the compound represented by the general formula (CMR32) preferably have two groups represented by -N(R 37 )(R 38 ), and each of the two coumarin skeletons preferably has one group represented by -N(R 37 )(R 38 ).

[0156] In the photo - up - conversion organic film of the present embodiment, it is preferable that 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 even more preferably an alkyl group having 1 to 6 carbon atoms.

[0157] In the photo - up - conversion organic film of the present embodiment, for example, the following compounds etc. can be used as the triplet sensitizer.

[0158]

Chemical formula

[0159] In the photo-upconversion organic film of this embodiment, the triplet sensitizer is preferably the compound (CBDAC). CBDAC is an abbreviation for 3,3'-carbonylbis(7-diethylaminocoumarin).

[0160] In the photo-upconversion organic film of this embodiment, the triplet sensitizer may be an organometallic complex. "Organometallic complex" includes both organometallic compounds having a metal-carbon bond and metal complexes having a coordination bond. A metal complex having a coordination bond includes a metal and a ligand that coordinates to it. The fact that the triplet sensitizer is an organometallic complex facilitates the transfer of light energy to the organic light-emitting material. The metal atoms constituting the organometallic complex as a triplet sensitizer are not particularly limited, but are, for example, at least one metal atom selected from the group consisting of Li, Mg, Al, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ru, Pd, Ag, Re, Os, Ir, Pt, and Pb. Preferably, the metal atoms constituting the organometallic complex as a triplet sensitizer are Pt or Pd.

[0161] In the photo-upconversion organic film of this embodiment, if the triplet sensitizer is an organometallic complex, it is preferable that the triplet sensitizer contains a platinum atom, and more preferably that it is an organometallic complex containing a platinum atom.

[0162] Examples of ligands in organometallic complexes include porphyrins such as octaethylporphyrin or their substituted derivatives; phthalocyanines such as tetra-tert-butyl phthalocyanine or their substituted derivatives; and naphthalocyanines such as tetra-tert-butyl naphthalocyanine or their substituted derivatives.

[0163] Examples of substituents in substituted products include hydrocarbon groups such as alkyl groups (methyl group, ethyl group, and t-butyl group, etc.), alkenyl groups (vinyl group and allyl group, etc.), and alkynyl groups (ethynyl group and propynyl group, etc.); and hydrocarbon groups having acidic groups such as carboxyalkyl groups (carboxymethyl group and carboxyethyl group, etc.).

[0164] Among these, porphyrin or its substituted derivatives and phthalocyanine or its substituted derivatives are preferred as ligands in organometallic complexes, porphyrin or its substituted derivatives are more preferred, and porphyrin substituted derivatives are even more preferred.

[0165] Specific examples of organometallic complexes used as triplet sensitizers include metal complexes of porphyrin or its substituted derivatives, and metal complexes of phthalocyanine or its substituted derivatives, among which metal complexes of porphyrin or its substituted derivatives are preferred.

[0166] The metal atoms contained in metallic porphyrins (metallic complexes of porphyrins) and metallic phthalocyanines (metallic complexes of phthalocyanines) are, for example, at least one metal atom selected from the group consisting of Pt, Pd, Ru, Rh, Ir, Zn, and Cu. Porphyrins and their substituted products are sometimes referred to as porphyrins, and phthalocyanines and their substituted products are sometimes referred to as phthalocyanines.

[0167] The organometallic complex used as a triplet sensitizer is preferably at least one metal complex selected from the group consisting of a Pt complex with porphyrin or its derivatives as a ligand, a Pt complex with phthalocyanine or its derivatives as a ligand, a Pt complex with naphthalocyanine or its derivatives as a ligand, a Pd complex with porphyrin or its derivatives as a ligand, a Pd complex with phthalocyanine or its derivatives as a ligand, and a Pd complex with naphthalocyanine or its derivatives as a ligand.

[0168] Examples of triplet sensitizers include compounds represented by the following general formula (20) that have an absorption maximum wavelength in the range of 500 nm to 700 nm and contain a metal in their structure.

[0169] [ka]

[0170] (In the above general formula (20), R 201 , R 202 , R 204 , R 205 , R 207 , R 208 , R 210 and R 211 Each of these is independently a hydrogen atom or any substituent containing a hydrophilic functional group, and R 201 , R 202 , R 204 , R 205 , R 207 , R 208 , R 210 and R 211 They are either identical or different from each other, R 201 , R 202 , R 204 , R 205 , R 207 , R 208 , R 210 and R 211 Two of these adjacent atoms may bond to each other to form a five-membered or six-membered ring having any substituent containing a hydrogen atom, R 203 , R 206 , R 209 and R 212 Each of these independently represents an aryl group having any substituent including a hydrogen atom, and R 203 , R 206 , R 209 and R 212 (These elements are either identical or different from each other, and M represents a metal atom.)

[0171] Here, "any substituent containing a hydrogen atom" means a hydrogen atom, or any substituent excluding a hydrogen atom. Furthermore, if there are multiple "any substituent containing a hydrogen atom," these "any substituent containing a hydrogen atom" may bond to each other to form a five-membered ring or a six-membered ring having any substituent containing a hydrogen atom, or they may not bond to each other.

[0172] 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 them is a hydrophilic functional group, and specific examples of hydrophilic functional groups include hydrogen atoms, alkyl groups (e.g., alkyl groups with 1 to 12 carbon atoms), alkenyl groups, alkynyl groups, halogen atoms, hydroxyl groups, alkylcarbonyloxy groups, arylcarbonyloxy groups, alkoxycarbonyloxy groups, carboxylates, alkylcarbonyl groups, arylcarbonyl groups, alkoxycarbonyl groups, aminocarbonyl groups, alkylaminocarbonyl groups, dialkylaminocarbonyl groups, alkylthiocarbonyl groups, alkoxy groups, phosphate bases, phosphonic acid bases, phosphinic acid bases, thiocarboxylic acid groups, sulfate bases, sulfenic acid bases, sulfinic acid bases, sulfonic acid bases, phosphate groups, phosphonic acid groups, phosphinic acid groups, thiocarboxylic acid groups, Examples of hydrophilic functional groups include sulfate groups, sulfenic acid groups, sulfinic acid groups, sulfonic acid groups, cyano groups, amino groups (including alkylamino groups, dialkylamino groups, arylamino groups, diarylamino groups, and alkylarylamino groups), acylamino groups (including alkylcarbonylamino groups, arylcarbonylamino groups, carbamoyl groups, and ureido groups), amidino groups, imino groups, sulfhydryl groups, alkylthio groups, arylthio groups, alkylsulfinyl groups, sulfamoyl groups, sulfonamide groups, nitro groups, trifluoromethyl groups, cyano groups, azide groups, heterocyclic groups, alkylaryl groups, or aryl or heteroaryl groups, but hydrophilic functional groups are not limited to these.

[0173] The following R is included in the general formula (20) mentioned above. 201 , R 202 , R 204 , R 205 , R 207 , R 208 , R 210 and R 211 Examples of substituents on a five-membered or six-membered ring formed by two adjacent rings being bonded to each other include R 201 , R 202 , R 204 , R 205 , R 207 , R 208 , R 210 and R 211 Examples of substituents include, but are not limited to, those listed above. The five-membered or six-membered ring may or may not be linked to other substituted or unsubstituted porphyrin rings.

[0174] R in the above general formula (20) 203 , R 206 , R 209 and R 212 For example, R 201 , R 202 , R 204 , R 205 , R 207 , R 208 , R 210 and R 211 Examples of substituents include those listed above, but are not limited to these.

[0175] The metal atom M in the general formula (20) is at least one metal atom selected from the group consisting of Pt, Pd, Ru, Rh, Ir, Zn, and Cu.

[0176] Examples of metal porphyrins represented by the general formula (20) include meso-tetraphenyl-tetrabenzoporphyrin metal complexes such as meso-tetraphenyl-tetrabenzoporphyrin palladium (CAS number: 119654-64-7), octaethylporphyrin metal complexes such as octaethylporphyrin palladium (CAS number: 24804-00-0), and octaethylporphyrin metal complexes such as meso-tetraphenyl-octamethoxy-tetranaphtho[2,3]porphyrin palladium described in the literature (Y. Murakami et al., J. Phy., Chem. B, 118 (2014) 14442).

[0177] Examples of metal tetraazaporphyrins include compounds represented by the following general formula (21).

[0178] [ka]

[0179] (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, respectively, R in the general formula (20). 201 , R 202 , R 204 , R 205 , R 207 , R 208 , R 210 , R 211 (And it is synonymous with M.)

[0180] Triplet sensitizers may be organic photosensitizing molecules with a structure that does not contain metals. By using metal-free triplet sensitizers, environmental contamination by metals can be avoided during the manufacturing and disposal of photo-upconversion organic films. Specific examples of metal-free triplet sensitizers include compounds represented by the following general formula (22) (borondipyrromethenes), C70, etc. These triplet sensitizers may be used individually or in combination of two or more.

[0181] [ka]

[0182] (In the above general formula (22), R 221 ~R 227 Each of these independently represents a hydrogen atom or any substituent containing a hydrophilic functional group, R 221 ~R 227 At least one of them is a hydrophilic functional group, R 221 ~R 227 Among the substituents that are adjacent to each other (R 221 and R 222 In contrast to, R 222 and R 223 In contrast to, R 225 and R 226 The opposite of, and R 226 and R 227 At least one pair of the pair may bond to each other to form a 5-membered or 6-membered ring having any substituent including a hydrogen atom, R 228 and R 229 Each of these independently represents a halogen atom, a hydrophilic functional group, a substituted or unsubstituted C1-C5 alkyl group, or a substituted or unsubstituted C1-C5 alkoxy group.

[0183] R in the general formula (22) 221 ~R 227At least one of them is a hydrophilic functional group, and specific examples of hydrophilic functional groups include hydrogen atoms, aliphatic hydrocarbon groups such as alkyl groups, alkenyl groups or alkynyl groups, halogen atoms, hydroxyl groups (hydroxyl groups), alkylcarbonyloxy groups, arylcarbonyloxy groups, alkoxycarbonyloxy groups, aryloxycarbonyloxy groups, carboxylates, alkylcarbonyl groups, arylcarbonyl groups, alkoxycarbonyl groups, aminocarbonyl groups, alkylaminocarbonyl groups, dialkylaminocarbonyl groups, alkylthiocarbonyl groups, alkoxy groups, phosphate bases, phosphonic acid bases, phosphinic acid bases, thiocarboxylic acid bases, sulfate bases, sulfenic acid bases, sulfinic acid bases, sulfonic acid bases, phosphate groups, phosphonic acid groups, Examples of such groups include, but are not limited to, phosphinic acid groups, thiocarboxylic acids, sulfate groups, sulfenic acid groups, sulfinic acid groups, sulfonic acid groups, cyano groups, amino groups (including alkylamino groups, dialkylamino groups, arylamino groups, diarylamino groups, and alkylarylamino groups), acylamino groups (including alkylcarbonylamino groups, arylcarbonylamino groups, carbamoyl groups, and ureido groups), amidino groups, imino groups, sulfhydryl groups, alkylthio groups, arylthio groups, alkylsulfinyl groups, sulfamoyl groups, sulfonamide groups, nitro groups, trifluoromethyl groups, cyano groups, azide groups, heterocyclic groups, alkylaryl groups, phenoxy groups, aryl groups, heteroaryl groups, or heteroaryloxy groups.

[0184] The substituents (R) adjacent to each other are included in the general formula (22) above. 221 and R 222 In contrast to, R 222 and R 223 In contrast to, R 225 and R 226 The opposite of, and R 226 and R 227 Examples of substituents on a five-membered or six-membered ring formed by the bonding of at least one pair of the pair with each other include R 221 ~R 227 Examples of substituents include those listed above, but are not limited to these.

[0185] R in the general formula (22) 221 , R 223 , R 225 and R 227 Each of these may independently be a hydrogen atom, a halogen atom, a hydrophilic functional group, a substituted or unsubstituted C1-C4 aliphatic hydrocarbon group, a substituted or unsubstituted phenyl group, a substituted or unsubstituted phenoxy group, a substituted or unsubstituted thienyl group, a substituted or unsubstituted thienoxy group, a 2-carboxylethenyl group represented by the following formula (23), or a 2-carboxyl-2-cyanoethenyl group represented by the following formula (24).

[0186] [ka]

[0187] R in the general formula (22) 222 and R 226 Preferably, each of these is independently a hydrogen atom, a halogen atom, a hydrophilic functional group, a substituted or unsubstituted C1-C4 aliphatic hydrocarbon group, a substituted or unsubstituted phenyl group, a substituted or unsubstituted phenoxy group, a substituted or unsubstituted thienyl group, a substituted or unsubstituted thienoxy group, a 2-carboxylethenyl group represented by formula (23), or a 2-carboxyl-2-cyanoethenyl group represented by formula (24). R in the general formula (22) 222 and R 226 Each of these is independently a hydrogen atom, a bromine atom, or an iodine atom, and R 222 and R 226 It is more preferable that at least one of them is a bromine atom or an iodine atom. R in the general formula (22) 222 and R 226 Each is independently a hydrogen atom or an iodine atom, and R 222 and R 226 It is even more preferable that at least one of them is an iodine atom.

[0188] R in the general formula (22) 224Preferably, is a hydrogen atom, a halogen atom, a hydrophilic functional group, a substituted or unsubstituted C1-C4 aliphatic hydrocarbon group, a substituted or unsubstituted phenyl group, a substituted or unsubstituted phenoxy group, a substituted or unsubstituted thienyl group, a substituted or unsubstituted thienoxy group, a 2-carboxylethenyl group represented by formula (23), or a 2-carboxyl-2-cyanoethenyl group represented by formula (24). R in the general formula (22) 224 It is more preferable that the group is a substituted or unsubstituted phenyl group. R in the general formula (22) 224 It is more preferable that the group is an unsubstituted phenyl group, an alkyl-substituted phenyl group, or a phenyl group having a hydrophilic functional group.

[0189] R in the general formula (22) 228 and R 229 Each of these is independently a halogen atom, a hydrophilic functional group, a substituted or unsubstituted C1-C5 alkyl group, or a substituted or unsubstituted C1-C5 alkoxy group, and R in the general formula (22) 228 and R 229 Preferably, it is a fluorine atom.

[0190] In the compound represented by the general formula (22) above, R 221 ~R 227 However, it is even more preferable that each compound independently comprises a hydrogen atom, a halogen atom, a hydrophilic functional group, a substituted or unsubstituted C1-C4 aliphatic hydrocarbon group, a substituted or unsubstituted phenyl group, a substituted or unsubstituted phenoxy group, a substituted or unsubstituted thienyl group, a substituted or unsubstituted thienoxy group, a 2-carboxylethenyl group represented by formula (23), or a 2-carboxyl-2-cyanoethenyl group represented by formula (24). The compound represented by the general formula (22) is more preferably a compound represented by the following general formula (25). A photon upconversion material with an even higher optical wavelength conversion efficiency can be realized using the compound represented by the following general formula (25).

[0191] [ka]

[0192] (In the above general formula (25), R 221 , R 223 , R 225 and R 227 Each of these independently represents a hydrophilic functional group, or a substituted or unsubstituted alkyl group having 1 to 3 carbon atoms, R 222 and R 226 Each of these independently represents a hydrogen atom, a bromine atom, or an iodine atom, and R 222 and R 226 At least one of them is a bromine atom or an iodine atom, R 224 (This represents a substituted or unsubstituted phenyl group.)

[0193] The triplet sensitizer may be a metal porphyrin represented by the general formula (20) or a compound represented by the general formula (22).

[0194] In the photo-upconversion organic film of this embodiment, specific examples of triplet sensitizers include, for example, the following compounds, but the present invention is not limited to these compounds.

[0195] [ka]

[0196] The photo-upconversion organic film of this embodiment can also be manufactured by any of the manufacturing methods described in the first, second, and third embodiments. Furthermore, the photo-upconversion organic film of this embodiment can also be manufactured using any of the manufacturing apparatus described in the first, second, and third embodiments.

[0197] According to this embodiment, it is possible to provide an organic photo-upconversion film that can stably upconvert visible light to ultraviolet light in the atmosphere and exhibit high upconversion quantum efficiency at an excitation light intensity lower than the intensity of sunlight irradiating the Earth's surface (for example, an intensity of about 0.3 times that of sunlight). Furthermore, according to one aspect of this embodiment, it is possible to provide an organic photo-upconversion film that exhibits high durability against excitation light and high light irradiation stability. The organic photo-upconversion film of this embodiment can function as an ultraviolet light generating material. Therefore, the organic photo-upconversion film of this embodiment can greatly expand the usefulness of ground-level sunlight in various regions that require ultraviolet light.

[0198] Furthermore, in the photo-upconversion organic film of this embodiment, since neither the triplet sensitizer nor the organic light-emitting material are ionic materials (ionic liquids), the photo-upconversion organic film of this embodiment is chemically stable. Moreover, the photo-upconversion organic film of this embodiment can be used in air and exhibits upconversion emission in air. The photo-upconversion organic film of this embodiment can be applied to various uses (for example, photocatalysts, solar cells, and photoorganic synthesis).

[0199] [Differentiation] The present invention is not limited to the embodiments described above, and any configurations obtained by modifications, improvements, and appropriate combinations of the embodiments, to the extent that they can achieve the objectives of the present invention, are included in the present invention.

[0200] In the first embodiment, the first heating section 131 is composed of first rod heaters 131A and 131B, and the second heating section 132 is composed of second rod heaters 132A and 132B. However, the first heating mechanism 13 is not limited to the rod heaters described above, and any heating mechanism that generates a temperature gradient along the X direction in the first clamping section 12A and the second clamping section 12B may be used. For example, a first electric heating wire heater may be wrapped around the -X side ends of the first clamping section 12A and the second clamping section 12B, and a second electric heating wire heater may be wrapped around the +X side ends, and a temperature gradient may be generated by controlling the current values ​​flowing through these electric heating wire heaters, respectively.

[0201] In the first embodiment, a configuration was shown in which temperature sensors 134, such as thermocouples, are provided on the first clamping portion 12A and the second clamping portion 12B. In the second and third embodiments, these temperature sensors may also be provided. For example, in the second embodiment, temperature sensors may be provided on a pair of guide plates 22A and 22B along the X direction to measure the temperature gradient on the guide plates 22A and 22B. In this case, feedback control of the second heating mechanism 23 may be performed based on the measured temperature gradient. Similarly, in the third embodiment, a temperature sensor may be provided for each of the multiple roller pairs 32. Alternatively, multiple temperature sensors may be provided for each of the pair of support plates 31A and 31B along the X direction.

[0202] In the first embodiment, a configuration was illustrated in which a pair of clamping parts 12A and 12B are sandwiched by an insulating material 135 to suppress heat outflow from the clamping parts 12A and 12B to the fixed stage 142 and the movable stage 143, but the embodiment is not limited thereto. In the first embodiment, in order to reduce the pressure inside the vacuum chamber 151, the heat insulation can be improved by creating gaps between the first clamping part 12A and the fixed stage 142, and between the second clamping part 12B and the movable stage 143.

[0203] In the first to third embodiments, examples were shown in which the installation environment of the precursor holding units 11, 21, and 31 is reduced in pressure and the powder precursor 111 is pressed, but the invention is not limited to this. For example, the powder precursor 111 may be pressed under atmospheric pressure, in which case the generation of bubbles can be suppressed by leaving it standing under atmospheric pressure. [Examples]

[0204] The present invention will be described in more detail below with reference to examples. The present invention is not limited to these examples.

[0205] <Compound> The structures of the triplet sensitizers used to prepare the photo-upconversion organic films in Examples 1-5 are shown below.

[0206] [ka]

[0207] The structures of the organic light-emitting materials used to fabricate the photo-upconversion organic films in Examples 1 to 5 are shown below.

[0208] [ka]

[0209] <Fabrication of photo-upconversion organic films> Using CBDAC as a triplet sensitizer and PPO as an organic light-emitting material, the photo-upconversion organic films of Examples 1 to 5 were fabricated as follows. We used 99% pure PPO from Sigma-Aldrich and CBDAC with a purity of over 98% from Tokyo Chemical Industry Co., Ltd. The purchased CBDAC was prepared as a methanol solution (4 × 10⁻⁶). -4 M) This CBDAC methanol solution was filtered using a PTFE membrane filter (Merck-LG, product name: SLLGX13NL, pore size: 200 nm) to remove any particulate matter that may be present in the CBDAC methanol solution. This methanol solution was used for sample preparation. Filtered CBDAC methanol solution (4 × 10 -4 M) was added dropwise to the PPO powder using a mechanical pipette to form a mixed powder of CBDAC and PPO (molar ratio of 1:30000). This mixture was evacuated for 15 minutes in a vacuum chamber connected to a dry scroll pump to remove methanol. Finally, this mixture was finely ground in a quartz mortar to obtain a homogeneous mixture of PPO and CBDAC. A mixed powder of CBDAC and PPO (mass: approximately 32 mg, CBDAC:PPO = 1:30000 (molar ratio)) was placed inside a SUS spacer ring (thickness: 200 μm, inner diameter: 8 mm) and sandwiched between two round glass substrates (Corning glass substrates (product name: EAGLE XG®, diameter: 12 mm, thickness: 0.7 mm) cut into a circular shape by Matsunami Glass Industry Co., Ltd.). When preparing the photo-upconversion organic film, a thin aluminum film (thickness: 50 nm) was deposited on only one side of both glass substrates, and the mixed powder was sandwiched between the sides of the glass substrates that did not have aluminum deposition. Furthermore, for the preparation of samples for optical property measurements described later, after the preparation of the photo-upconversion organic film, the glass substrate to which the organic film was attached and the glass substrate without aluminum deposition were used. Furthermore, for the preparation of samples for optical microscope observation using transmitted illumination from the bottom, described later, two glass substrates without aluminum deposition were used. In this manner, the precursor holding section was prepared, and a photo-upconversion organic film was fabricated according to the [method for producing a photo-upconversion organic film] described in the first embodiment. The photo-upconversion organic films in Examples 1 to 5 were fabricated by controlling the temperature difference ΔT at both ends of a pair of clamping portions 12A and 12B to less than 1.3°C for Example 1, 10°C for Example 2, 20°C for Example 3, 25°C for Example 4, and 30°C for Example 5. Figures 13(a) to (e), similar to Figure 5, show time-dependent temperature profiles recorded by thermocouples. Figure 13(a) shows the temperature change in Example 1 (ΔT < 1.3°C), Figure 13(b) shows the temperature change in Example 2 (ΔT = 10°C), Figure 13(c) shows the temperature change in Example 3 (ΔT = 20°C), Figure 13(d) shows the temperature change in Example 4 (ΔT = 25°C), and Figure 13(e) shows the temperature change in Example 5 (ΔT = 30°C). Regarding ΔT, due to the presence of a heat sink attached to only one side, the minimum possible ΔT was 0.9 ± 0.4°C, so the ΔT for Example 1 is expressed as ΔT < 1.3°C. In Figures 13(a) to (e), the solid lines correspond to lines L1 to L5 in Figure 5, and the dashed lines correspond to lines L6 to L8 in Figure 5. melt(PPO) This is the melting temperature of PPO, and T solid(PPO) This is the solidification temperature of PPO. In Examples 1 to 5, the cooling rate was -3°C / min. The photo-upconversion organic films prepared in Examples 1-5 are considered to be free of organic solvents due to the vacuum evacuation during the preparation of the mixed powder and the production of the photo-upconversion organic films. Even if organic solvents are present, they are considered to be in extremely small amounts below the detection limit.

[0210] <Evaluation of physical properties, etc.> (Observation with an optical microscope) Optical microscopy observation was performed on each of the light upconversion organic films in Examples 1 to 5. Optical microscopy observation was performed using a polarizing microscope with transmitted illumination (microscope manufactured by Olympus Corporation: product name "BX-53"). Observation with the polarizing microscope was performed in a crossed nicol configuration. Figure 14 shows three types of photographs for each of the photo-upconversion organic films from Examples 1 to 5. The top row of Figure 14 shows stereomicroscope images of the obtained photo-upconversion organic films taken with transmitted illumination, while the middle and bottom rows show magnified microscope images of the photo-upconversion organic films taken with transmitted illumination. The middle row is a normal microscope image, and the bottom row is a polarized microscope image. The rightward arrow between the top and middle rows of Figure 14 indicates a temperature gradient, with high temperature on the left and low temperature on the right. From the image shown in Figure 14, it was found that the photo-upconversion organic films in Examples 1-5 were mainly composed of single-crystal stripes grown along the temperature gradient. Therefore, it was found that the crystals of the organic light-emitting material (PPO), which is the main constituent material of the photo-upconversion organic films in Examples 1-5, have uniaxial orientation. In this specification, "uniaxial orientation" means that the polycrystalline domains forming the photo-upconversion organic film elongate in the direction of the temperature gradient to form crystal stripes, and that the direction of elongation approximately follows the direction of the temperature gradient, and does not mean that the direction of elongation strictly coincides with the direction of the temperature gradient. Furthermore, when organic films made of PPO alone without CBDAC were observed using the same rhinoscopic method as above, it was found that PPO is a material with uniaxial orientation. In Example 1, under the condition ΔT < 1.3°C, a microcrystalline film with strong light scattering was formed. This is thought to be due to sudden solidification across the entire sample area. In Example 3, under the condition ΔT = 20°C, relatively clear single-crystal stripes, mainly grown along the temperature gradient, were observed in the photo-upconversion organic film. The width of the single-crystal stripes observed under a microscope was mainly in the range of 30 μm to 80 μm. The results shown in Figure 14 illustrate the effect of the temperature gradient on the properties of the obtained photo-upconversion organic film. Similar directional crystallization along the temperature gradient can also be observed in films formed on a substrate from molten p-type and n-type organic semiconductor blends. As in Examples 4 and 5, when ΔT was increased to 25°C to 30°C, the photo-upconversion organic film underwent microcrystallization, and the transparency of the film decreased. This indicates that ΔT=20°C, as in Example 3, provided a more appropriate cooling rate for the solidification front necessary to achieve crystal stripe growth. Furthermore, the photo-upconversion organic film produced under the conditions of ΔT=20°C and a cooling rate of -1°C / min was also a microcrystalline film. It was found that adjusting the cooling rate to an appropriate level is desirable to prevent disruption of the directionality of crystal stripe growth.

[0211] (X-ray diffraction measurement and single-crystal X-ray structural analysis) Powder X-ray diffraction (PXRD) measurements were performed on the organic light-emitting material used as a raw material and the fabricated organic light-upconversion film. PXRD measurements were performed using an X-ray diffractometer (manufactured by Rigaku Corporation, product name: SmartLab) at 298K using Cu Kα radiation. The optical upconversion organic film was cut into fine powder using a razor blade and annealed at 66°C for 30 minutes in a dry nitrogen gas atmosphere. Approximately 50 mg of the annealed fine powder was sandwiched between two Mylar® films and set on the measurement stand of the X-ray diffractometer. During the measurement, the measurement stand was rotated at 120 rpm, the scan step was set to 0.01°, and the scan speed was set to 0.5° / min. Figure 15 shows the powder X-ray diffraction (PXRD) patterns. In Figure 15, the top row shows the PXRD pattern of the obtained PPO powder, the middle row shows the PXRD pattern of the photo-upconversion organic film of Example 3 (UC film, ΔT=20℃), and the bottom row shows the PXRD pattern of the photo-upconversion organic film of Example 1 (UC film, ΔT<1.3℃). Figure 15 shows that the photo-upconversion organic films produced in the examples showed the same PXRD pattern as the PPO powder, indicating the absence of polymorphism.

[0212] Figure 16 shows the crystal structure of PPO obtained by Pawley and Rietveld analysis. The Pawley and Rietveld analysis was performed using molecular modeling and simulation software (Dassault Systèmes, Ltd., product name: BIOVIA Materials Studio 2022®). The Pawley and Rietveld analysis revealed the herringbone packing of PPO.

[0213] (Photophysical properties) Figure 17 shows the photophysical properties of the photo-upconversion organic film and CBDAC. First, Figure 17 shows the excitation spectrum of the optical upconversion organic film of Example 3, which was fabricated at ΔT = 20°C. The excitation spectrum was obtained by irradiating the optical upconversion organic film with pulsed light generated from a tunable optical parametric oscillator (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 laser light varied from 410 nm to 488 nm while maintaining the pulse energy at 10 μJ. Figure 17 also shows a methanol solution of CBDAC (concentration: 2 × 10⁻⁶). -4 The absorption spectrum of M) (optical path length = 1 mm) is also shown. When the photo-upconversion organic films of Examples 1 to 5 were irradiated with laser light at a wavelength of λ = 440 nm, UC emission peaking in the wavelength range of 390 nm to 393 nm was observed, and fluorescence from CBDAC peaking in the wavelength range of 480 nm to 490 nm was also observed. The UC emission intensity from the photo-upconversion organic film of Example 3 (ΔT = 20°C) was stronger than that of the photo-upconversion organic film of Example 1 (ΔT < 1.3°C), which is due to the higher crystallinity of the photo-upconversion organic film of Example 3.

[0214] The optical physical properties were measured using setup E10, as described in Figure 18(A). A 440 nm continuous wave (CW) laser was emitted from the laser oscillator E11. The CW laser passed through the neutral density filter (ND filter) E12, beam expander E13, and iris E14 before irradiating sample E20. The laser beam diameter at the location of sample E20 was approximately 3 mm, and the beam profile was top-hat shaped. Figure 18(B) shows an enlarged cross-sectional view of sample E20 used for measuring the optical physical properties. On one side of the glass substrate E21 of sample E20, a 200 μm thick optical upconversion organic film E22 is held, surrounded by a 200 μm thick spacer E23. On the other side of the glass substrate E21, a 50 nm thick aluminum layer is provided as an optical reflection layer E24. The glass substrate E21 of sample E20 was positioned so that the laser irradiated the photo-upconversion organic film E22, and was held at a slight angle (approximately 5°) with respect to the perpendicular incidence direction of the laser beam, as schematically shown in Figure 18(A). Two achromatic lenses E15 and E16 were used to collect photoelectron emissions from the photo-upconversion organic film E22, and focused them into the entrance slit of a monochromator E17 (Princeton Instruments, product name: SP-2300i). The spectrum was recorded with an array CCD detector E18 (Princeton Instruments, product name: "PIXIS:100BR") mounted at the exit of the monochromator E17.

[0215] The fluorescence quantum yield Φ of CBDAC in a photo-upconversion organic film in which a trace amount of CBDAC is doped into a polycrystalline PPO film. F(S) (See Figure 12) The absolute PL quantum yield was measured to be 5.1% using a Hamamatsu Photonics K.K. product name: Quantaurus-QY. Therefore, the optical upconversion quantum efficiency (UC quantum efficiency) Φ UCThis can be determined by referring to the fluorescence intensity after correcting for the wavelength dependence of the diffraction gratings of the CCD detector and monochromator. Here, photoelectron emission at a wavelength λ ≤ 425 nm is defined as UC emission. Under this definition, 60.1% of the UC photons of the photo-upconversion organic film in Example 3 (ΔT = 20°C) were ultraviolet (UV) photons with a wavelength λ less than 400 nm. The photo-upconversion organic film in Example 3 had a higher efficiency (maximum Φ) than the photo-upconversion organic film in Example 1 (ΔT < 1.3°C). UC = 4.3%, and the normalized upconversion luminous efficiency η UC = 8.6%. UC ≡2Φ UC ) was shown.

[0216] (Excitation threshold intensity) The photo-upconversion organic film of Example 3 has a lower excitation threshold intensity (I) than the photo-upconversion organic film of Example 1. th This was shown (see Figures 19(A) and (B)). Figures 19(A) and (B) show the relationship between Φ and excitation intensity at a wavelength of 440 nm. UC The dependence is shown. Figure 19(A) is a graph relating to the photo-upconversion organic film of Example 3, and Figure 19(B) is a graph relating to the photo-upconversion organic film of Example 1. In Figures 19(A) and (B), 10 samples each of the photo-upconversion organic films of Example 1 and Example 3 were prepared and Φ UC The measured data is shown, with the plot representing the measured values ​​and the solid line representing the theoretical curve fit. Upconversion threshold intensity of the fabricated photo-upconversion organic film (unit: mW / cm²) 2The upconversion emission intensity was measured using the following method. In upconversion emission by TTA, it is known that in regions with low excitation light intensity, the upconversion emission intensity is proportional to the square of the excitation light intensity, and in regions with high excitation light intensity, the upconversion emission intensity is proportional to the first power of the excitation light intensity. The excitation light (wavelength 440 nm) intensity dependence of the upconversion emission intensity was measured, and the excitation light intensity at which the slope of the intensity dependence changes from 2 to 1 on a log-log plot was defined as the upconversion threshold intensity. The lower the threshold intensity, the more efficient upconversion emission is occurring at lower excitation light intensities.

[0217] Figure 20 shows the excitation threshold intensity (I) of the photo-upconversion organic film fabricated under the condition ΔT=20℃. th ) and the molar ratio M of PPO and CBDAC A / M S A graph showing the relationship is presented. Mole ratio M A / M S This is the number of moles M of CBDAC in the photo-upconverted organic film. S The number of moles of PPO relative to M A This is the ratio. The molar ratio of the triplet sensitizer to the organic light-emitting material contained in the photo-upconversion organic film corresponds directly to the material charging ratio when preparing the mixed powder. As shown in Figure 20, the molar ratio M A / M S When it exceeds 10000, the excitation threshold intensity (I th ) tended to become even lower. Molar ratio M A / M S It was found that adjusting this setting further improved the performance of the photo-upconversion organic film.

[0218] Furthermore, based on the dependence of UC emission intensity on the intensity of simulated sunlight (unit: SUN), the excitation threshold intensity (I) in the case of sunlight irradiation is determined. thThe intensity of sunlight was also measured. The simulated sunlight for Air Mass 1.5 (AM1.5) was generated by a solar simulator (manufactured by Asahi Spectroscopic Co., Ltd., product name: HAL-320). Broadband light generated from the solar simulator was passed through a long-pass filter to irradiate an organic optical upconversion film with light consisting only of wavelengths greater than 413 nm (λ>413 nm), and the UC emission intensity was measured. AM1.5 refers to the solar spectrum intensity that falls on the Earth, and is a global standard data set by the National Renewable Energy Laboratory (NREL) of the U.S. Department of Energy, with SUN as the unit representing the intensity of sunlight. The intensity of the simulated sunlight at the sample location was set as follows. First, without using a long-pass filter, a 1SUN checker (manufactured by Asahi Spectroscopic Co., Ltd., product name: CS-20) was placed at the sample location, and its intensity was set to the intensity of "one day" by adjusting the output of the solar simulator. Next, a long-pass filter was installed. After installation, this long-pass filter showed a transmittance of approximately 98% in the wavelength range of CBDAC light absorption. Therefore, to compensate for the decrease in light intensity at the sample location due to the installation of this long-pass filter, the output of the solar simulator was increased by 1.02 times. The light intensity at the sample location under these conditions was defined as 1 SUN. The measurement procedure 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. Figure 21 shows a graph illustrating the dependence of the photo-upconversion emission intensity on sunlight intensity. Figure 21 also shows the dimensionless excitation intensities (Λ) for two samples (Sample #1 and #2) of the photo-upconversion organic film in Example 3 (ΔT=20℃). The excitation threshold intensity (I) of the photo-upconversion organic film in Example 3 is also shown. thThe value of ) was found to be approximately 0.3 SUN. This indicates that the photo-upconversion organic film of Example 3 can be used in sunlight without a focusing optical system. In Figure 21, the plots show the measured values ​​and the theoretical curve fit. The inset in Figure 21 shows the emission spectrum from a sample under 1 SUN irradiation (solid line) and the emission spectrum from a reference sample prepared without the use of a sensitizer (dotted line). In Figures 19 and 21, the excitation light power was first increased, and data indicated by the unfilled marks was obtained. Subsequently, data indicated by the filled marks was obtained to confirm reproducibility and sample stability. The theoretical fit curve and dimensionless excitation intensity Λ are based on the literature (Y. Murakami and K. Kamada, Phys. Chem. Chem. Phys., 2021, 23, 18268). Dimensionless excitation intensity Λ = 2 corresponds to the excitation threshold intensity (I th This corresponds to ).

[0219] (Photostability) Figure 22 shows a graph relating to the photostability of the photo-upconversion organic film. Using the apparatus shown in Figure 18, the photo-upconversion organic film of Example 3 (ΔT=20℃) was subjected to a 440 nm laser beam at 30 mW / cm² in air. 2 The photostability was evaluated by continuous irradiation at the specified intensity. The vertical axis of the graph in Figure 22 shows the optical upconversion emission intensity corrected for the time variation of the laser light, as shown in the inset. As shown in Figure 22, this photostability test was conducted in air using a laser beam with λ=440 nm at an excitation threshold intensity (I th ) far exceeds 30 mW / cm² 2 Despite being irradiated at high intensity, it exhibited excellent photostability for at least 100 hours, significantly exceeding the photostability of conventional TTA-UC.

[0220] (Practicality) Figure 23 shows a schematic diagram of an experimental method illustrating an example of the practical application of photo-upconversion organic films. Two empty glass vials E27a and E27b (both identical, with an outer diameter of 8 mm and a height of 35 mm) were prepared, and a small amount of UV-curing resin E26 (manufactured by Bondic, product name: BD-SKCJ) was applied to the upper surface of the mouths of glass vials E27a and E27b. A glass slide E25 was placed on top of the UV-curing resin E26 to cover the mouths of glass vials E27a and E27b. Next, a glass substrate E21 on which the photo-upconversion organic film E22 from Example 3 (ΔT=20℃) was fabricated was placed on the glass slide E25 at a position corresponding to the mouth of one glass vial E27a, and a glass substrate E21 on which a comparative film Ref without a triplet sensitizer was fabricated was placed at a position corresponding to the mouth of the other glass vial E27b. The comparative film Ref was fabricated in the same manner as in Example 3, except that it did not contain a triplet sensitizer (CBDAC). Light E28, exceeding 413 nm (λ>413 nm) and passed through a long-pass filter, was generated using a solar simulator and irradiated from above the photo-upconversion organic film E22 and the comparative film Ref for 3 minutes. After irradiation, only the UV-curable resin E26 placed beneath the photo-upconversion organic film E22 cured, and the glass vial E27a adhered to the glass slide E25. On the other hand, the UV-curable resin E26 placed beneath the comparative film Ref did not cure, and the glass vial E27b did not adhere to the glass slide E25. These experimental results demonstrate the practicality of the photo-upconversion organic film of the present invention in air.

[0221] (Fluorescence quantum yield) Fluorescence quantum yield of PPO Φ F(A) The fluorescence quantum yield was 79%. The quantum yield was measured using an absolute PL quantum yield analyzer (Hamamatsu Photonics K.K., product name: Quantaurus-QY). For PPO in solid form, the fluorescence quantum yield Φ F(A) We measured it.

[0222] (Melting point and freezing point) Melting point (T) of the substance to be measured, such as PPO, CBDAC, and PPO-CBDAC blends. melt (represented by) and freezing point (T solidThe temperature (represented by ) was measured using a differential scanning calorimeter (Shimadzu Corporation, product name: DSC-60) at a temperature scan rate of 5°C / min. The melting point of PPO was 69°C.

[0223] (Inter-system crossover quantum yield) Intersystem crossover quantum yield Φ of CBDAC in benzene ISC It has been reported that the figure is 92% (see DPSpecht, PAMartic and S.Farid, Tetrahedron, 1982, 38, 1203). [Explanation of Symbols]

[0224] 10, 20, 20A, 30… Organic film manufacturing apparatus (photo-upconversion organic film manufacturing apparatus), 11, 21, 31… Precursor holding section, 12A… First clamping section, 12B… Second clamping section, 13… First heating mechanism, 14… Pressing mechanism (pressing section), 15, 25, 35… Reduced pressure mechanism, 16, 26, 36… Control 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, 1 12A...Glass substrate, 112B...Glass substrate, 113...Spacer, 114...Holding space, 122...O-ring (cushioning member), 131...First heating unit, 131A, 131B...First rod heater, 132...Second heating unit, 132A, 132B...Second rod heater, 133...Cooling unit, 134...Temperature sensor, 135...Insulation material, 144...Biasing member, 161...First heating drive circuit, 162...Second heating drive circuit, 163...Cooling drive circuit, 164...Depressurization drive circuit, 165...Processor, 231...Rod heater, 321...Roller.

Claims

1. A method for manufacturing an organic film that is upconverted to light, A precursor holding step involves holding a powder precursor containing a triplet sensitizer and an organic light-emitting material in the holding space of a precursor holding section having a holding space of a predetermined height, A pressing step of pressing the powder precursor along the height direction of the holding space, A temperature control step in which, with one direction perpendicular to the height direction as the axial direction, one end of the powder precursor in the axial direction as the first end, and the other end of the powder precursor in the axial direction as the second end, the temperature of the first end of the powder precursor is heated to a temperature above the melting point of the organic light-emitting material, and then the temperature of the first end and the second end is gradually reduced to below the freezing point of the organic light-emitting material while maintaining the temperature difference between the first and second temperatures, A method for manufacturing an organic film that performs optical upconversion.

2. A method for producing a photo-upconversion organic film according to claim 1, wherein a cooling rate for gradually decreasing the temperature of the powder precursor is predetermined in relation to the temperature difference, and the cooling rate is increased as the temperature difference increases.

3. A method for manufacturing an organic film that is upconverted to light, A precursor holding step involves holding a powder precursor containing a triplet sensitizer and an organic light-emitting material in the holding space of a precursor holding section having a holding space of a predetermined height, A pressing step of pressing the powder precursor along the height direction of the holding space, A temperature control step involves moving a heating member, which has a temperature gradient along the axial direction from a high temperature range above the melting point of the organic light-emitting material to a low temperature range below the solidification point of the organic light-emitting material, relative to the precursor holding portion in the axial direction, with the axial direction being defined as the axial direction, A method for manufacturing an organic film that performs optical upconversion.

4. The pressing step involves reducing the pressure in the environment where the precursor holding unit is installed and pressing the powder precursor. A method for producing an organic film for photo-upconversion according to any one of claims 1 to 3.

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

6. The aforementioned organic light-emitting material includes an oxazole derivative, The method for producing a photo-upconversion organic film according to any one of claims 1 to 5, wherein the triplet sensitizer comprises a coumarin derivative.

7. A photo-upconversion organic film manufacturing apparatus for manufacturing photo-upconversion organic films, A precursor holding unit having a holding space of a predetermined height, which holds a powder precursor containing a triplet sensitizer and an organic light-emitting material in the holding space, A pair of clamping parts that clamp the precursor holding part in the height direction, A pressing portion that presses at least one of the pair of clamping portions toward each other, A first heating mechanism generates a temperature gradient along the axial direction by heating the powder precursor to different temperatures, with one direction perpendicular to the height direction as the axial direction, one end of the powder precursor in the axial direction being designated as the first end, and the other end of the powder precursor in the axial direction being designated as the second end, the temperature of the first end being designated as the first temperature, and the temperature of the second end being designated as the second temperature, and heating the powder precursor to different temperatures, the first and second temperatures are set to the first and second temperatures, respectively. Equipped with, The first heating mechanism heats the first and second temperatures to above the melting point of the organic light-emitting material, and then gradually reduces the first and second temperatures to below the freezing point of the organic light-emitting material while maintaining the temperature difference between the first and second temperatures. Photonic upconversion organic film manufacturing system.

8. The first heating mechanism is, The first heating portion is provided on one end of the clamping portion in the axial direction, A second heating unit is provided on the other end of the clamping portion in the axial direction and is drivable independently of the first heating unit, A cooling section is provided on the other end side in the axial direction of the clamping portion and cools the second end, The photo-upconversion organic film manufacturing apparatus according to claim 7, comprising:

9. The first heating section is a first rod heater embedded in one end of the pair of clamping sections in the axial direction, The second heating section is a second rod heater embedded in the other axial end of each of the pair of clamping sections. The optical upconversion organic film manufacturing apparatus according to claim 8.

10. The precursor holding portion is a pair of substrates spaced apart in the height direction via a spacer, and the holding space is formed by the gap between the pair of substrates. Between the pair of clamping portions, the precursor holding portion and the cushioning member that absorbs the stress in the height direction are provided. The optical upconversion organic film manufacturing apparatus according to any one of claims 7 to 9.

11. The device further comprises the precursor holding portion, the pair of clamping portions, the pressing portion, and a pressure reduction mechanism for maintaining the surrounding environment of the first heating mechanism in a reduced pressure state. The optical upconversion organic film manufacturing apparatus according to any one of claims 7 to 10.

12. The photo-upconversion organic film manufacturing apparatus according to any one of claims 8 to 11, further comprising a heat insulating material provided in contact with the side of the pair of clamping portions opposite to the side that clamps the precursor holding portion.

13. A photo-upconversion organic film manufacturing apparatus for manufacturing photo-upconversion organic films, A precursor holding unit having a holding space of a predetermined height, which holds a powder precursor containing a triplet sensitizer and an organic light-emitting material in the holding space, A member for pressing and clamping the precursor holding portion in the height direction, comprising a pair of guide portions that guide the precursor holding portion so that it can move relative to the precursor holding portion along the axial direction, with one direction perpendicular to the height direction as the axial direction, A second heating mechanism heats the guide portion such that a temperature gradient is generated 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 solidification point of the organic light-emitting material. A moving mechanism for moving the precursor holding portion relative to the guide portion in the axial direction, A photo-upconversion organic film manufacturing apparatus equipped with the following features.

14. The precursor holding portion is a pair of substrates spaced apart in the height direction via a spacer, and the holding space is formed by the gap between the pair of substrates. The pair of guide portions are a pair of guide plates that clamp the precursor holding portion in the height direction, The second heating mechanism heats the guide plates such that a temperature gradient is created in the pair of guide plates such that the temperatures of the opposing positions on the guide plates are the same. The moving mechanism presses the precursor holding portion between a pair of guide plates in the axial direction to move the precursor holding portion relative to the guide portion. The photo-upconversion organic film manufacturing apparatus according to claim 13.

15. The precursor holding portion comprises a pair of substrates spaced apart in the height direction via a spacer, and a pair of support plates that sandwich the pair of substrates and have an axial length longer than that of the substrates, and the holding space is formed by the gap between the pair of substrates. The pair of guide sections is configured such that a plurality of roller pairs, each forming a pair in the height direction, are arranged in the axial direction, and the precursor holding section is held between the pair of rollers forming a pair in the height direction. The moving mechanism rotates the roller, thereby moving the precursor holding portion relative to the pair of guide portions in the axial direction. The second heating mechanism individually controls the temperature of each roller pair arranged in the axial direction such that the roller pairs with high temperatures are arranged in order from the roller pair with a high temperature range to the roller pair with a low temperature range along the axial direction. The photo-upconversion organic film manufacturing apparatus according to claim 13.

16. The second heating mechanism heats the guide portion such that a temperature gradient is created along the axial direction in the order of the low temperature region, the high temperature region, and the low temperature region. The optical upconversion organic film manufacturing apparatus according to any one of claims 13 to 15.

17. It is a photo-upconversion organic film, It comprises a triplet sensitizer and an organic light-emitting material. The aforementioned organic light-emitting material has ultraviolet light emission properties, A photo-upconversion organic film, which is a crystalline film.

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

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

20. The aforementioned organic light-emitting material includes an oxazole derivative. The photo-upconversion organic film according to any one of claims 17 to 19.

21. The fluorescence quantum yield of the aforementioned organic light-emitting material is 40% or more. The photo-upconversion organic film according to any one of claims 17 to 20.

22. The aforementioned triplet sensitizer does not contain metal atoms in its molecule. The photo-upconversion organic film according to any one of claims 17 to 21.

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

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

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

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