Method for producing diamond particles

Abstract

To provide a method for synthesizing diamond particles from a solution by using ultraviolet rays.SOLUTION: The method for synthesizing diamond particles of the present invention includes mixing an organic solvent and a photoradical polymerization initiator to obtain a solution, and irradiating the solution with ultraviolet light.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for producing diamond particles. [Background technology]

[0002] Diamond not only has high hardness, but also many other properties, such as high thermal conductivity, a wide band gap, a high breakdown field, a low dielectric constant, excellent radiation resistance, and excellent chemical stability. Therefore, diamond is expected to be used in a wide range of applications, from jewelry to cutting tools, heat sinks, short-wavelength LEDs, vacuum switches, electrodes, power devices, and quantum sensors.

[0003] Well-known methods for synthesizing diamond include high-temperature and high-pressure methods (see, for example, Non-Patent Documents 1 to 3), chemical vapor deposition methods (see, for example, Non-Patent Documents 1 to 3), and detonation methods (see, for example, Non-Patent Documents 1 to 3).

[0004] The high-temperature, high-pressure method requires special equipment because synthesis is carried out under harsh conditions such as high temperature and pressure. Chemical vapor deposition requires a precision device, consumes a lot of energy to generate plasma, and does not convert the gas introduced into the device into diamond efficiently. The detonation method requires a large amount of energy for detonation and places a heavy burden on the environment.

[0005] In contrast to these methods, the method of synthesizing diamond from a solution does not require special equipment and consumes less energy and places less strain on the environment than the above methods, making it a promising synthesis method for the future. As a method for synthesizing diamond from a solution, for example, Patent Document 1 discloses a method for synthesizing diamond, which is characterized by using a cathode and an anode with a diamond seed crystal attached to the surface, and electrolyzing an aqueous solution of a water-soluble organic acid having two or more carbon atoms in a subcritical state, thereby growing diamond on the surface of the anode.

[0006] Furthermore, Patent Document 2 discloses a method for obtaining diamond particles by mixing a solvent containing a carbon-containing organic solvent with a salt to obtain a mixed liquid, and then aging the mixed liquid. [Prior art documents] [Non-patent literature]

[0007] [Non-Patent Document 1] F. Bundy et al., Nature 176, 51-55 (1955) [Non-patent document 2] S.Matsumoto et al., Jpn.J.Appl.Phys. 21, L183 (1982) [Non-patent document 3] VVDanilenko, Phys.Solid State 46, 595-599(2004) [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 2019-135315 [Patent Document 2] Japanese Patent Application Publication No. 2023-91834 Summary of the Invention [Problem to be solved by the invention]

[0009] An object of the present invention is to provide a new method for synthesizing diamond particles from solution. [Means for solving the problem]

[0010] The present invention proposes the following manufacturing methods [1] to [9] as a new method for synthesizing diamond particles from a solution.

[0011] [1] The first aspect of the manufacturing method of the present invention is a method for manufacturing diamond particles, characterized in that an organic solvent and a photoradical polymerization initiator are mixed to obtain a mixed solution, and the mixed solution is irradiated with active energy rays.

[0012] [2] The second aspect of the manufacturing method of the present invention is a method for manufacturing diamond particles according to the first aspect, wherein the organic solvent is at least one selected from the group consisting of aromatic hydrocarbons, aliphatic hydrocarbons, halogenated hydrocarbons, alcohols, ketones, amides, ethers, esters, glycols, and glycol ethers. [3] The third aspect of the manufacturing method of the present invention is a method for manufacturing diamond particles, wherein the organic solvent is at least one selected from the group consisting of acetone, ethanol, and cycloheptane, in the manufacturing method of the first or second aspect.

[0013] [4] A fourth aspect of the manufacturing method of the present invention is a method for manufacturing diamond particles, wherein in the manufacturing method of any one of the first to third aspects, the photoradical polymerization initiator is at least one compound selected from the group consisting of benzophenone-based, benzil ketal-based, thioxanthone-based, acetophenone-based, acylphosphine oxide-based, α-hydroxyacetophenone-based, and α-aminoacetophenone-based compounds. [5] A fifth aspect of the manufacturing method of the present invention is a method for manufacturing diamond particles according to any one of the first to fourth aspects, wherein the photoradical polymerization initiator is a benzyl ketal compound.

[0014] [6] The sixth aspect of the manufacturing method of the present invention is a method for manufacturing diamond particles, wherein the amount (g) of the photoradical polymerization initiator mixed relative to the amount (L) of the organic solvent mixed is 0.001 g / L to 1000 g / L in the manufacturing method of any one of the first to fifth aspects. [7] The seventh aspect of the manufacturing method of the present invention is a method for manufacturing diamond particles according to any one of the first to sixth aspects, in which active energy rays having an energy peak in the wavelength range of 100 nm to 400 nm are irradiated.

[0015] [8] A ninth aspect of the manufacturing method of the present invention is a method for manufacturing diamond particles, in which, in the manufacturing method of any one of the first to seventh aspects, the mixed solution is maintained at a temperature range of 0°C or more and 200°C or less while the mixed solution is irradiated with active energy rays. [9] A tenth aspect of the manufacturing method of the present invention is a method for manufacturing diamond particles according to any one of the first to eighth aspects, wherein the reaction atmosphere is maintained at atmospheric pressure or the saturated vapor pressure of the organic solvent while the mixed solution is irradiated with active energy rays. [Effects of the Invention]

[0016] According to the method for producing diamond particles proposed by the present invention, diamond particles can be obtained by mixing an organic solvent with a photoradical polymerization initiator and irradiating the mixed solution with active energy rays to cause a reaction. This eliminates the need to prepare diamond seed crystals and does not require expensive equipment, making it advantageous for practical use. [Brief explanation of the drawings]

[0017] [Figure 1] 1A and 1B are diagrams schematically illustrating a method for manufacturing diamond particles as an example of an embodiment of the present invention. [Figure 2] 1 is a scanning electron microscope photograph of diamond particles obtained in Examples 1 and 2. [Figure 3] 1 is an X-ray diffraction chart of the diamond particles obtained in Examples 1 and 2. DETAILED DESCRIPTION OF THE INVENTION

[0018] The present invention will be described below based on one embodiment, but the present invention is not limited to this embodiment.

[0019] <Production method of the present invention> A method for producing diamond particles according to one embodiment of the present invention (also referred to as the "production method of the present invention") is a method in which an organic solvent and a photoradical polymerization initiator are mixed to obtain a mixed solution, and the mixed solution is irradiated with active energy rays to cause a reaction to obtain diamond particles.

[0020] Irradiating a photo-radical polymerization initiator with active energy rays generates radicals, such as methyl radicals. These radicals act as starting points for reactions, such as coupling between radicals. For example, ethane becomes an ethyl radical, which then becomes propane, producing a long carbon chain. Hydrogen atoms are then extracted from the ethyl radical, and the hydrogen atoms are replaced with methyl groups. This process repeats, gradually replacing the C—H bonds with C—C bonds. Since radicals, such as methyl radicals, are continuously supplied from the photo-polymerization initiator, this reaction is thought to be repeated to form diamond nuclei and grow into diamond particles. Furthermore, CH in the organic solvent may be involved in the radical reaction, or the organic solvent may also supply radicals, such as methyl radicals, to the radical reaction system. It is presumed that the radicals that may be involved in the production method of the present invention include alkyl radicals such as ethyl radicals and propyl radicals in addition to methyl radicals.

[0021] <Organic solvents> In the production method of the present invention, the organic solvent mainly plays a role of providing a field for radical movement, and may also play a role of supplying CH and radicals to the radical reaction. Therefore, the organic solvent used in the production method of the present invention is not particularly limited as long as it is an organic compound that is liquid at room temperature and normal pressure, in other words, a liquid containing carbon at room temperature and normal pressure, and examples thereof include aromatic hydrocarbons, aliphatic hydrocarbons, halogenated hydrocarbons, alcohols, ketones, amides, ethers, esters, glycols, and glycol ethers.

[0022] Among these, acetone, ethanol, diethyl ether, isopropyl alcohol, cycloheptane, etc. can be mentioned as preferred examples from the viewpoint of solubility of the photoradical polymerization initiator and suitable fluidity.

[0023] Diamonds are also known as sp 3 Since the tetrahedron structure is connected three-dimensionally by hybrid orbitals, it is sp 3 Rather than creating hybrid orbitals, the original sp 3 It is believed that hybrid orbitals are more advantageous for the formation of diamond nuclei. 3 Organic solvents with hybrid orbitals are preferred. 3 Examples of the organic solvent having a hybrid orbital include acetone, ethanol, diethyl ether, and cycloheptane.

[0024] The organic solvent used in the production method of the present invention may be at least one selected from the group consisting of the organic solvents listed above, and may also be a mixture of two or more types. The organic solvent used in the production method of the present invention may contain water. In this case, the concentration of the organic solvent is preferably 90% by mass or more, more preferably 95% by mass or more, and even more preferably 99.5% by mass or more. Note that, when the organic solvent contains water, "the concentration of the organic solvent is preferably 90% by mass or more" is synonymous with "the content of water in the organic solvent is preferably 10% by mass or less."

[0025] Examples of the aromatic hydrocarbons include toluene, p-xylene, o-xylene, mesitylene, ethylbenzene, cumene, styrene, etc. These may be used alone or in combination of two or more.

[0026] Examples of the aliphatic hydrocarbons include methane, ethane, propane, butane, n-pentane, n-hexane, cyclopentane, cyclohexane, cycloheptane, etc. These may be used alone or in combination of two or more.

[0027] Examples of the halogenated hydrocarbons include chlorobenzene, orthodichlorobenzene, chloroform, dichloromethane, dibromomethane, 1,2-dichloroethane, trifluoromethylbenzene, 3-methoxybenzotrifluoride, 3-methoxybenzotrifluoride, etc. These may be used alone or in combination of two or more.

[0028] Examples of the alcohols include methanol, ethanol, propanol, 2-propanol, allyl alcohol, butanol, isobutyl alcohol, tert-butyl alcohol, pentanol, 2-methylbutanol, 2-methyl-2-butanol, cyclohexanol, 2-methylpentanol, octanol, 2-ethylhexanol, benzyl alcohol, furfuryl alcohol, tetrahydrofurfuryl alcohol, etc. These may be used alone or in combination of two or more.

[0029] Examples of the ketones include acetone, ethyl methyl ketone, isopropyl methyl ketone, isobutyl methyl ketone, butyl methyl ketone, diacetone alcohol, diethyl ketone, cyclopentanone, cyclohexanone, etc. These can be used alone or in combination of two or more.

[0030] Examples of the amides include N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N-cyclohexyl-2-pyrrolidone, etc. These can be used alone or in combination of two or more.

[0031] Examples of the ethers include diethyl ether, diisopropyl ether, tetrahydrofuran, 1,4-dioxane, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, triethylene glycol dimethyl ether, etc. These can be used alone or in combination of two or more.

[0032] Examples of the esters include ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, isobutyl acetate, ethyl lactate, γ-butyrolactone, ethyl benzoate, methyl benzoate, benzoyl benzoate, 2-ethylhexyl benzoate, ethyl 4-methylbenzoate, etc. These may be used alone or in combination of two or more.

[0033] Examples of the glycols include ethylene glycol, propylene glycol, hexylene glycol, trimethylene glycol, diethylene glycol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, etc. These may be used alone or in combination of two or more.

[0034] Examples of the glycol ethers include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monobutyl ether, propylene glycol monomethyl ether acetate, butylene glycol monomethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monoethyl ether acetate, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, etc. These may be used alone or in combination of two or more.

[0035] <Photoradical polymerization initiator> The photoradical polymerization initiator used in the production method of the present invention is not particularly limited in type as long as it absorbs active energy rays to generate radicals. Among these, those that generate radicals when exposed to ultraviolet light, such as benzophenones, benzil ketals, thioxanthones, acetophenones, acylphosphine oxides, α-hydroxyacetophenones, or α-aminoacetophenones, whose absorption wavelength range is in the ultraviolet region, are preferred.

[0036] In the present invention, the term "based" means to include derivatives, for example, "benzophenone-based" means to include not only benzophenone but also derivatives of benzophenone. The same applies to other photoradical polymerization initiators.

[0037] Furthermore, the photoradical polymerization initiator used in the production method of the present invention is more preferably one that absorbs ultraviolet light to generate methyl radicals. The photoradical polymerization initiator that generates a methyl radical may be any one that has a moiety that generates a methyl radical, and examples thereof include benzophenone-based, benzil ketal-based, thioxanthone-based, acetophenone-based, acylphosphine oxide-based, α-hydroxyacetophenone-based, and α-aminoacetophenone-based compounds. Among these, from the viewpoint of the efficiency of generating methyl radicals, benzoin methyl ether, benzyl dimethyl ketal, etc. can be mentioned, and a mixture of these may also be used. Among these, benzyl ketal compounds are preferred in terms of the low toxicity of the by-products.

[0038] Examples of the benzophenone-based photoradical polymerization initiator include benzophenone, 2-ethylanthraquinone, 4-4'-bis(methylamino)benzophenone, p-methylbenzophenone, and methyl 2-benzoylbenzoate.

[0039] Examples of the benzyl ketal-based photoradical polymerization initiator include benzyl dimethyl ketal.

[0040] Examples of the thioxanthone-based photoradical polymerization initiator include 2,4-diethyl-9H-thioxanthen-9-one.

[0041] Examples of the acetophenone-based photoradical polymerization initiator include acetophenone and 2-(hydroxyimino)propiophenone.

[0042] Examples of the acylphosphine oxide-based photoradical polymerization initiator include diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide and phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide.

[0043] Examples of the α-hydroxyacetophenone-based photoradical polymerization initiator include 1-hydroxycyclohexyl phenyl ketone, 2-isopropoxy-2-phenylacetophenone, and 2-hydroxy-4′-(2-hydroxyethoxy)-2-methylpropiophenone.

[0044] Examples of the α-aminoacetophenone-based photoradical polymerization initiator include 2-methyl-4′-(methylthio)-2-morpholinopropiophenone, 2-benzyl-2-(dimethylamino)-4′-morpholinobutyrophenone, and the like. These may be used alone or in combination of two or more.

[0045] <Mixing ratio> The amount (g) of the photoradical polymerization initiator mixed relative to the amount (L) of the organic solvent mixed is preferably 0.001 g / L to 1000 g / L. Photoradical polymerization initiator is the radical supply source of the starting point of above-mentioned reaction, so from the viewpoint of easily forming diamond nucleus, the amount (g) of photoradical polymerization initiator mixed is preferably 0.001g / L or more, more preferably 0.01g / L or more, and even more preferably 0.05g / L or more.On the other hand, although there is no particular limitation about upper limit value, from the viewpoint of ensuring fluidity, and also from the viewpoint of practicality and economic efficiency, it is preferably 1000g / L or less, more preferably 500g / L or less, and even more preferably 200g / L or less.

[0046] <Other ingredients> "Other components" may be added to the solution obtained by mixing the organic solvent and the photoradical polymerization initiator. Examples of "other components" include, but are not limited to, diamondoids such as adamantane. Diamondoids partially have a structure similar to that of diamond, and therefore can promote the generation and growth of diamond particles.

[0047] <Mixed> The organic solvent, the photoradical polymerization initiator, and other components may be mixed by a known method, such as by using a magnetic stirrer, a shaker, a planetary stirrer, an ultrasonic device, etc. However, the method is not limited to these.

[0048] <Activated energy ray irradiation reaction> By irradiating a mixed solution obtained by mixing an organic solvent and a photoradical polymerization initiator with active energy rays, radicals, such as methyl radicals, can be continuously generated. Starting from these radicals, carbon chains extend, and further, a reaction in which C—H bonds are successively replaced by C—C bonds is repeated, forming diamond nuclei and then diamond particles.

[0049] The type of active energy ray is not limited as long as it can activate the photopolymerization initiator to generate radicals, and examples thereof include far ultraviolet rays, ultraviolet rays, near ultraviolet rays, infrared rays, and visible light rays. Among these, ultraviolet light is preferred in view of the wide variety of photopolymerization initiators available, ease of reaction control, curing speed, ease of availability of irradiation equipment, cost, and the like. That is, active energy rays (ultraviolet rays) having an energy peak in the wavelength range of 100 nm to 400 nm, especially 250 nm to 375 nm, and especially 254 nm to 355 nm are preferred. Ultraviolet rays in this wavelength range can be used in germicidal lamps and are readily available. Furthermore, because ultraviolet rays are less attenuated in the atmosphere, they can be used without creating a vacuum in the passageway, eliminating the need for special equipment configurations, which is preferable for industrial applications.

[0050] Examples of light sources for irradiating active energy rays include high-pressure mercury lamps, ultra-high-pressure mercury lamps, low-pressure mercury lamps, carbon arc lamps, metal halide lamps, xenon lamps, chemical lamps, electrodeless discharge lamps, and LEDs.

[0051] (Reaction time) The irradiation time of the active energy rays, i.e., the time for which the active energy rays are irradiated to cause a reaction, is thought to increase or decrease depending on the reaction temperature, the intensity of the ultraviolet rays, the type of the photoradical polymerization initiator, etc. Therefore, although the active energy rays are irradiated for one month in the examples described below, it can be said that there is a good possibility that the irradiation time will be shorter than this.

[0052] (temperature) While the mixed solution is being irradiated with active energy rays, the mixed solution is preferably kept at a temperature in the range of 0°C or higher and 200°C or lower. It is believed that increasing the temperature of the mixed solution makes it easier for the reaction to proceed and can promote the production of diamond particles, so it is preferable to maintain the temperature at 0°C or higher, more preferably at 10°C or higher, and especially at 30°C or higher. On the other hand, to prevent volatilization and simplify the equipment, it is preferable to maintain the temperature at 200°C or less, more preferably at 100°C or less, and even more preferably at 50°C or less.

[0053] (pressure) During irradiation of the mixed solution with active energy rays, the reaction atmosphere is preferably maintained under atmospheric pressure or the saturated vapor pressure of the organic solvent in order to prevent the organic solvent from volatilizing. In this case, the reaction atmosphere refers to the atmosphere in the space within the reaction vessel, for example, when the mixed solution is placed in a reaction vessel and irradiated with active energy rays.

[0054] (collect) After the ultraviolet irradiation, it is preferable to carry out the steps of removing the solvent, recovering the produced particles and washing them.

[0055] <Diamond particles of the present invention> The diamond particles produced by the production method of the present invention (also referred to as "diamond particles of the present invention") are single-crystal particles having a cubic and / or hexagonal crystal structure. The crystalline structure of diamond can be analyzed by measuring electron diffraction or fast Fourier transform (FFT) patterns. However, CH or CO may be present on the outermost surface of the diamond particles of the present invention.

[0056] The manufacturing method of the present invention involves mixing an organic solvent with a photoradical polymerization initiator and then irradiating it with active energy rays to cause a reaction, so there is no room for unnecessary components to enter, and in that sense it is possible to obtain diamond particles with an extremely low amount of impurities.

[0057] <Application> The diamond particles of the present invention can be suitably used in jewelry, abrasives, cutting tools, heat sinks, laser windows, lenses, detectors, medical scalpels, dental drills, biosensors, short-wavelength LEDs, vacuum switches, electrodes, power devices, quantum sensors, etc. In particular, the diamond particles of the present invention have an extremely low impurity content and are therefore suitable for use as quantum sensors with high sensitivity and high spatial resolution. They are also expected to be used in medical devices such as magnetocardiographs and magnetoencephalographs, as well as in on-board sensors for electric vehicles. [Example]

[0058] An example of an embodiment of the present invention will be described below, but the present invention is not limited to the embodiment described below.

[0059] The following examples and comparative examples were carried out using the materials described below.

[0060] [material] <Organic solvents> Acetone (Fujifilm Wako Pure Chemical Industries, Ltd., purity: 99.5%+ by mass) Cycloheptane (Tokyo Chemical Industry Co., Ltd., purity: >98% by mass)

[0061] <Photoradical polymerization initiator> Benzyl dimethyl ketal (Tokyo Chemical Industry Co., Ltd., purity: >98% by mass)

[0062] [Examples 1 and 2] A photoradical polymerization initiator was added to an organic solvent in a quartz glass container at the blending ratio shown in Table 1 below (the "concentration" in the table indicates the ratio (g / mL) of the amount of photoradical polymerization initiator mixed (g) to the amount of organic solvent mixed (mL)), and the mixture was mixed using a magnetic stirrer to obtain a mixed solution. The quartz glass container containing this mixed solution was placed in a thermostatic chamber maintained at 40°C, and the mixed solution was irradiated with ultraviolet light having an energy peak of 254 nm using a "Tabletop Stand Type 27W Short Wavelength Ultraviolet Germicidal Lamp" (manufactured by Optocord Co., Ltd.) for one month. The inside of the quartz glass container was kept at atmospheric pressure without being pressurized.

[0063] After the reaction was completed, the particles were separated and collected using a membrane filter, and the collected particles were washed several times with ethanol and water to obtain particles (sample). The obtained particles (samples) were observed and evaluated for particle shape and particle size using a backscattered electron scanning electron microscope (see Figure 2). At this time, the magnification was set so that about 100 particles were present per screen, and 10 representative particles were selected from among them and their particle sizes were measured. The particle sizes were found to be in the range of 70 to 130 nm. In addition, the generated particles (sample) were identified by X-ray diffraction analysis (X-ray source: CuKα rays) (Figure 3).

[0064] [Comparative Examples 1 to 2] The organic solvent was irradiated with ultraviolet light in the same manner as in Examples 1 and 2, except that no photoradical polymerization initiator was added.

[0065] [Table 1]

[0066] <Result> As shown in Table 1, particle generation was confirmed in Examples 1 and 2. On the other hand, particle generation was not confirmed in Comparative Examples 1 and 2, in which only the organic solvent was irradiated with ultraviolet light. 3, the particles (samples) produced in Examples 1 and 2 showed clear diffraction peaks. When indexed using Miller indices, the confirmed diffraction peaks were attributed to the {111} plane of cubic diamond, indicating that the obtained particles (samples) were diamond particles with a cubic crystal structure.

[0067] <Consideration> A comparison between Examples 1 and 2 shows that the generation of diamond particles is not affected by the type of organic solvent. This supports the idea that in the production method of the present invention, the main role of the organic solvent is to provide a place for radicals to move, and that another role is to supply radicals or CH sources to the radical reaction, so that the type of organic solvent is not limited as long as it is an organic compound that is liquid at room temperature and normal pressure.

[0068] Comparing Examples 1 and 2 with Comparative Examples 1 and 2, it was shown that a photoradical polymerization initiator is required for the production of diamond particles. This can be understood as the radical species generated from the photoradical polymerization initiator by ultraviolet irradiation participating in the formation of a diamond structure with C-C bonds. The presumed mechanism is that methyl radicals generated by irradiating a photoradical polymerization initiator with ultraviolet light act as the starting point, generating long carbon chains such as ethane ⇒ ethyl radical ⇒ propane, from which hydrogen atoms are extracted and replaced with methyl groups, a process that repeats itself; in other words, the internal C-H bonds are successively replaced with C-C bonds, and methyl radicals are continuously supplied from the photopolymerization initiator, so it is thought that diamond nuclei are formed by repeating this process, and then grow into diamond particles. In view of this mechanism, it can be considered that any photoradical polymerization initiator that absorbs active energy rays to generate radicals will exhibit the same effect.

[0069] From the above examples and the results of tests conducted by the inventors up to now, it has been discovered that diamond particles can be synthesized from a solution by irradiating ultraviolet light onto a solution in which a photoradical polymerization initiator is mixed with an organic solvent. The method of synthesizing diamond from a solution discovered in the present invention does not require the expensive equipment required for conventional diamond synthesis methods such as high-temperature and high-pressure methods, chemical vapor deposition methods, and detonation methods. Furthermore, since the manufacturing method of the present invention is a method for synthesizing diamond particles from a solution, there is no room for impurities to be contained, and it can be applied to fields such as semiconductors, which require high purity. Furthermore, it is speculated that if an element source such as B or N is intentionally added to the solution, these elements will be doped into the synthesized diamond particles. In particular, N-doped diamond has a unique luminescence center, making it applicable to quantum fields.

Claims

1. A method for producing diamond particles, comprising: mixing an organic solvent and a photoradical polymerization initiator to obtain a mixed solution; and irradiating the mixed solution with active energy rays.

2. 2. The method for producing diamond particles according to claim 1, wherein the organic solvent is at least one selected from the group consisting of aromatic hydrocarbons, aliphatic hydrocarbons, halogenated hydrocarbons, alcohols, ketones, amides, ethers, esters, glycols and glycol ethers.

3. 2. The method for producing diamond particles according to claim 1, wherein the organic solvent is at least one selected from the group consisting of acetone, ethanol, and cycloheptane.

4. 2. The method for producing diamond particles according to claim 1, wherein the photoradical polymerization initiator is at least one compound selected from the group consisting of benzophenone-based, benzil ketal-based, thioxanthone-based, acetophenone-based, acylphosphine oxide-based, α-hydroxyacetophenone-based, and α-aminoacetophenone-based compounds.

5. The method for producing diamond particles according to claim 1 , wherein the photoradical polymerization initiator is a benzyl ketal compound.

6. 2. The method for producing diamond particles according to claim 1, wherein the amount (g) of the photoradical polymerization initiator mixed relative to the amount (L) of the organic solvent mixed is 0.001 g / L to 1000 g / L.

7. 2. The method for producing diamond particles according to claim 1, wherein the active energy rays have an energy peak in the wavelength range of 100 nm to 400 nm.

8. The method for producing diamond particles according to claim 1, wherein the mixed solution is maintained at a temperature in the range of 0°C to 200°C while the mixed solution is irradiated with active energy rays.

9. 2. The method for producing diamond particles according to claim 1, wherein the reaction atmosphere is maintained at atmospheric pressure or the saturated vapor pressure of the organic solvent while the mixed solution is irradiated with active energy rays.

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