Color conversion particles

Abstract

To provide color conversion particles having higher light absorption performance and durability than conventional ones.SOLUTION: The color conversion particles have chalcogenide perovskite as a base material and contain at least one dopant of rare earth ions and transition metal ions as a luminescent center.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to color conversion particles. [Background technology]

[0002] Conventionally, color conversion using wavelength conversion (down-conversion), in which excitation light incident on an object from the outside is converted into light of a longer wavelength and then emitted, has been widely used in lighting, display devices, solar cells, and the like. For example, phosphors containing an activator may be used in this type of color conversion (see, for example, Patent Documents 1 to 3). However, conventional activated phosphors using oxides, nitrides, or fluorides as host materials are difficult to form into nanoparticles, making them unsuitable for application to display devices, such as micro LEDs (light-emitting diodes), which are becoming increasingly miniaturized.

[0003] As one of the means for solving the above problems, activated semiconductor nanoparticles, in which an activator is added to a semiconductor material that can be formed into nanoparticles, have been investigated (see, for example, Non-Patent Document 1). Examples of host materials for activated semiconductor nanoparticles include Cd(S,Se), InP, APbX3 (A = Cs,MA; X = Cl,Br,I), and Zn(S,Se). Regarding the above host materials, methods for synthesizing nanoparticles on the scale of several nm are known. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6443417 [Patent Document 2] Patent No. 5954355 [Patent Document 3] Japanese Patent Application Laid-Open No. 2015-137328 [Non-patent literature]

[0005] [Non-Patent Document 1] Riccardo Marin et al., “Doping Lanthanide Ions in Colloidal Semiconductor Nanocrystals for Brighter Photoluminescence”, Chem. Rev. 2021, 121, 1425-1462 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the light absorption performance of activated semiconductor nanoparticles depends on the absorption efficiency (absorption coefficient) of the semiconductor host material. For example, to apply activated semiconductor nanoparticles to display devices that require color conversion without transmitting blue excitation light, the light absorption performance of conventional activated semiconductor nanoparticles is still insufficient, and a host material with a higher absorption coefficient is required.

[0007] Furthermore, in display devices such as micro LEDs, phosphors are placed on top of blue LEDs, so this type of color conversion particle must also be highly durable and resistant to deterioration in the harsh environments in which the device operates, at high temperatures and with light exposure.

[0008] The present invention has been made in view of the above circumstances, and provides color conversion particles that have higher light absorption performance and durability than conventional particles. [Means for solving the problem]

[0009] The color conversion particles of one embodiment of the present invention have a base material of chalcogenide perovskite and contain at least one dopant selected from rare earth ions and transition metal ions as luminescent centers. [Effects of the Invention]

[0010] According to one aspect of the present invention, it is possible to provide color conversion particles that have higher light absorption performance and durability than conventional particles. [Brief explanation of the drawings]

[0011] [Figure 1] 1A and 1B are schematic diagrams showing examples of the configuration of color conversion particles according to an embodiment of the present invention. [Figure 2] 1 is a graph showing the emission spectrum of color conversion particles of an example. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, an embodiment will be described with reference to the drawings. In the embodiments, in order to make the explanation easier to understand, structures or elements other than the main parts of the present invention will be described in a simplified or omitted manner. Furthermore, in the drawings, the same elements are given the same reference numerals. Note that the shapes, dimensions, etc. of each element in the drawings are shown schematically and do not represent the actual shapes, dimensions, etc.

[0013] <Color conversion particle structure> FIG. 1 is a schematic diagram showing an example of the configuration of the color conversion particles of this embodiment. The color conversion particles 10 of this embodiment are doped phosphors with nanometer-sized particles in their overall shape. The color conversion particles 10 absorb incident excitation light and re-emit (emit) it as light with different energy (wavelength), thereby converting color.

[0014] The color conversion particles 10 use chalcogenide perovskite as the base material 11, and at least one of rare earth ions and transition metal ions as the dopant 12 added to the base material 11. The color conversion particles 10 absorb incident excitation light by the chalcogenide perovskite of the base material 11, and emit light of a desired wavelength from the dopant 12 in the luminescence center.

[0015] (Base material 11) The chalcogenide perovskite, which is the base material 11, is a semiconductor made up of a group of perovskite crystal structures containing a chalcogen element (S, Se, Te) at the X site.

[0016] Perovskites, as mentioned above, are a group of substances with a cubic crystal structure based on a BX6 octahedron, represented by the chemical formula ABX3. Due to lattice distortion, they can take on tetragonal or orthorhombic crystal structures. Furthermore, several stable crystal structures have been shown to exist for the same ABX3 composition through computational science. These crystal structures range from structures close to perovskite to structures that are quite different. Furthermore, derivative structures exist, such as Ruddlesden-Popper and Dion-Jacobson layered perovskites based on the perovskite structure, as well as double perovskite crystal structures in which different elements are alternately arranged at the B site. In this specification, the above crystal structures are collectively referred to as the "perovskite crystal structure group."

[0017] The perovskite crystal structure group specifically includes substances having the following crystal structures: Cubic perovskite, tetragonal perovskite, GdFeO3-type orthorhombic, YScS3-type orthorhombic, NH4CdCl3-type orthorhombic, BaNiO3-type hexagonal, FePS3-type monoclinic, PbPS3-type monoclinic, CeTmS3-type monoclinic, Ruddlesden-Popper-type layered perovskite, Dion-Jacobson-type layered perovskite, double perovskite The perovskite crystal structure group changes its crystal structure and electronic structure depending on the composition and synthesis conditions, which in turn changes its optoelectronic and chemical properties. Therefore, the composition and synthesis conditions are selected to obtain a crystal structure suitable for the purpose.

[0018] For example, materials with cubic perovskite, tetragonal perovskite, GdFeO3-type orthorhombic perovskite, Ruddlesden-Popper-type layered perovskite, and double perovskite structures have excellent optoelectronic and chemical properties. Furthermore, by using a Dion-Jacobson-type layered perovskite structure, chemical stability can be further improved. In particular, materials with a GdFeO3-type orthorhombic perovskite crystal structure, represented by ABX3 (A = Group 2, B = Group 4), are known to have excellent photoelectron properties, including a high optical absorption coefficient.

[0019] The chemical formula of chalcogenide perovskite is ABX3,A'2A n-1 B n X 3n+1 , A''A'''B''2X7, A''A2B''3X 10 , which can be expressed as A2BB'X6. In the above chemical formula, X represents a chalcogen element (S, Se, Te). A and A' represent Group 2 elements (Ca, Sr, Ba), A'' represents Group 1 elements (Li, Na, K, Rb, Cs), and A''' represents Group 3 elements (rare earth elements) and Bi. B and B' represent Group 4 elements (Ti, Zr, Hf), and B'' represents Group 5 elements (V, Nb, Ta). Also, n is a positive integer. Note that A and A', and B and B' may be the same element. Also, A, A', A'', A''', B, B', B'', and X include mixtures of elements from each group in any ratio.

[0020] When a dopant 12 (described later) is added to the base material 11, the dopant 12 may replace some of the elements constituting the base material 11. For example, when Eu is added as the dopant 12 to the base material 11, SrHfS3 is used. 3+ When Sr is added, the composition of the color conversion particles 10 becomes 1-x ,EU x )HfS3 and Sr(Hf 1-y ,EU y For example, the composition of the color conversion particles 10 may be (Sr 1-x ,EU x ) HfS3 (where 0.01≦x≦0.10).

[0021] As an example, chalcogenite perovskite represented by the chemical formula ABX3 includes the following materials: In the following example, X is selected from the predominant chalcogen elements (S, Se), A is selected from the predominant Group 2 elements (Sr, Ba), and B is selected from the predominant Group 4 elements (Zr, Hf). SrZrS3, SrZrSe3, SrHfS3, SrHfSe3, BaZrS3, BaZrSe3, BaHfS3, BaHfSe3

[0022] As an example, the chemical formula A'2A n-1 B n X 3n+1 Chalcogenite perovskites expressed as follows include the following materials: X is selected from the dominant chalcogen elements (S, Se), A and A' are selected from the dominant Group 2 elements (Sr, Ba), and B is selected from the dominant Group 4 elements (Zr, Hf). Sr2Ba n-1 Zr n S 3n+1 , Sr2Ba n-1 Zr n Se 3n+1 , Sr n+1 Zr n S 3n+1 , Sr n+1 Zr n Se 3n+1 , Ba2Sr n-1 Zr n S 3n+1 , Ba2Sr n-1 Zr n Se 3n+1 , Ba n+1 Zr n S 3n+1 , Ba n+1 Zr n Se 3n+1 , Sr2Ba n-1 Hf n S 3n+1 , Sr2Ba n-1 Hf n Se 3n+1 , Sr n+1 Hf n S 3n+1 , Srn+1 Hf n Se 3n+1 , Ba2Sr n-1 Hf n S 3n+1 , Ba2Sr n-1 Hf n Se 3n+1 , Ba n+1 Hf n S 3n+1 , Ba n+1 Hf n Se 3n+1

[0023] These chalcogenide perovskites (Sr x Ba 1-x )(Zr y Hf 1-y )(S z Se 1-z )3 or (Sr x’ Ba 1-x’ )2(Sr x Ba 1-x ) n-1 (Zr y Hf 1-y ) n (S z Se 1-z ) 3n+1 (where x, x', y, and z are each a value between 0 and 1).

[0024] In chalcogenide perovskites, the carrier concentration, crystal structure, and other physical and chemical properties can be controlled by partial substitution of constituent elements with elements from the same or different groups. For example, elements from group 1 can be substituted with elements from groups 1 and 2, elements from group 2 with elements from groups 1, 2, and 3, elements from group 3 with elements from groups 2, 3, and 4, elements from group 4 with elements from groups 3, 4, and 5, and elements from group 16 with elements from groups 15, 16, and 17.

[0025] (Dopant 12) The amount of dopant 12 added to the base material 11 is preferably greater than 0 (at %) and not more than 25 (at %). Furthermore, if the amount of dopant 12 added is large, defects tend to occur in the crystal, resulting in a decrease in emission intensity and an increase in the half-life value of the emission spectrum, so the amount added is more preferably 10 (at %) or less. The dopant 12 is selected from the following rare earth ions and transition metal ions so that the color conversion particles 10 can emit light at a desired wavelength.

[0026] The rare earth ions added as the dopant 12 include all divalent or trivalent lanthanoid elements, such as Eu 3+ ,EU 2+ , Ce 3+ , Gd 3+ Although not particularly limited, rare earth ions include Tm 3+ , Er 3+ , Pr 3+ , Dy 3+ , Ho 3+ , Tb 3+ , Sm 3+ ,EU 3+ ,EU 2+ , Ce 3+ is preferred.

[0027] The transition metal ions added as the dopant 12 include, for example, Co 3+ , Ni 2+ , Fe 3+ , Mn 5+ , Mn 4+ , Mn 3+ , Mn 2+ , Cr 4+ , Cr 3+ , V 5+ , V 4+ , V 3+ , Ti 4+ , Ti 3+ , Cu 2+ Examples include:

[0028] (Size of color conversion particles 10) Although there are no particular limitations, the particle size at which the color conversion particles 10 can exist stably is preferably 1 nm or more.

[0029] Furthermore, if the particle size of the color conversion particles 10 becomes too large, when a large number of color conversion particles 10 are contained in a film, coating, resin, etc., the gaps between the particles become larger, reducing the density of the color conversion particles 10. In this case, the absorbance of the wavelength conversion material using the color conversion particles 10 is reduced. Furthermore, when applying ink in which the color conversion particles 10 are dispersed in a solvent using, for example, an inkjet method, if the particle size of the color conversion particles 10 is too large, it can cause nozzle clogging. In other application methods as well, the large particle size of the color conversion particles 10 can pose a problem in the process. From the above viewpoint, the particle size of the color conversion particles 10 is preferably 500 nm or less, more preferably 100 nm or less, and even more preferably 20 nm or less.

[0030] <Method of manufacturing color conversion particles 10> Next, we will explain the method for producing the color conversion particles 10. The color conversion particles 10 can be produced by liquid phase synthesis or solid phase synthesis.

[0031] When producing color-converting particles 10 by reacting a precursor compound and a dopant in a solution, for example, a hot injection method, a heat-up method, a solvothermal method, a hydrothermal method, a CHM (composite-hydroxide-mediated) method, a continuous flow process synthesis method, etc. can be applied.

[0032] As an example, a case will be described in which color conversion particles 10 using BaZrS3 as a base material are synthesized in a liquid phase by a heat-up method. In this case, for example, metal dithiocarbamate (DTC)-based compounds can be used as precursor compounds, as they are highly soluble in organic solvents and can be thermally decomposed at low temperatures (below 300 °C). For example, a Ba-containing precursor compound is barium dibutyldithiocarbamate (BaDBuDTC), and a Zr-containing precursor compound is zirconium diethyldithiocarbamate (ZrDEtDTC). These precursor compounds can be used to synthesize BaS and ZrS2. Because the metal sulfide monomers are produced directly from the thermal decomposition of the metal DTC, no additional sulfur source is required for the reaction.

[0033] These precursor compounds may be doped with, for example, M(NR2) x or M(S2CNR2) x The mixture is heated to the desired reaction temperature (e.g., 330°C). The heating temperature is increased to the reaction temperature at a predetermined rate (e.g., 5°C / min). The reaction time can be set appropriately. Here, M is a dopant element. R is a hydrogen atom, a saturated hydrocarbon group having 1 to 20 carbon atoms, or an unsaturated hydrocarbon. When one ligand contains two or more R, the R may be the same or different.

[0034] After the reaction, the product is dispersed in an organic solvent such as toluene, and the initial precipitate phase, which does not form a stable dispersion in the organic solvent, is isolated by centrifugation. The remaining supernatant, containing the target product, can then be recovered by a second centrifugation.

[0035] As another example of liquid phase synthesis of color conversion particles 10 using BaZrS3 as a base material, the following method may be used.

[0036] For example, Ba[N(TMS)2]2(THF)2, Zr[N(CH3)2]4, and N,N'-diethylthiourea, with M(NR2) as the dopant. x or M(S2CNR2) xThe reaction mixture is heated to the desired reaction temperature (e.g., 365°C), held at that temperature for 30 minutes, and then cooled to room temperature. The target product is then precipitated and washed using anhydrous chloroform and ethanol, allowing the product to be isolated. Here, M is a dopant element. R is a hydrogen atom, a saturated hydrocarbon group having 1 to 20 carbon atoms, or an unsaturated hydrocarbon. When one ligand contains two or more R, the R may be the same or different.

[0037] Furthermore, when the color conversion particles 10 are manufactured using solid-phase synthesis, as in conventional solid-phase synthesis, a mixture of a precursor compound containing a Group II element or a Group IV element, a precursor compound containing a chalcogen element, and a dopant is heated in a reaction vessel from room temperature to a temperature in the range of 400°C to 1300°C, and then maintained at the aforementioned temperature for 0 to 200 hours to allow the reaction to occur.

[0038] For example, when the color conversion particles 10 having BaZrS3 as the base material are manufactured by solid phase synthesis, Eu 3+ BaZrO3 doped with CS2 is reacted with CS2 at 1050°C for 4 hours in an argon atmosphere. This allows the target product to be obtained by solid phase synthesis.

[0039] For example, when producing color conversion particles 10 using BaZrS3 as the base material by solid-phase synthesis, the BaS and ZrS2 raw materials are mixed with EuCl3 or EuS3 as a dopant, and then pulverized and mixed. The mixture is then reacted at 800°C to 1000°C for 15 hours. This allows the target product to be obtained by solid-phase synthesis.

[0040] For example, when producing color conversion particles 10 using AZrS3 (A = Ba, Sr) as the base material by solid-phase synthesis, EuCl3 or EuS3 is added as a dopant to the AS (A = Ba, Sr) raw material, Zr raw material, and S raw material, and the mixture is reacted using I2 as a catalyst to obtain the target product. In this case, in the case of BaZrS3, the reaction is carried out at 600°C for 60 hours, and in the case of SrZrS3, the reaction is carried out at 850°C to 1100°C for 60 hours.

[0041] By reducing the amount of raw materials used for the base material, some of the constituent elements of the chalcogenide perovskite, the base material that makes up the color conversion particles, are replaced with dopants, making it easier to incorporate dopants into the chalcogenide perovskite. For example, Eu 3+ When 5% of Sr is added, it is preferable to charge them in a ratio of Sr:Hf:S=0.95:1.00:3.00.

[0042] The effects of the color conversion particles 10 of this embodiment will be described below. The color conversion particles 10 of this embodiment have a base material 11 for absorbing excitation light that is a chalcogenide perovskite, and contain a dopant 12 of at least one of rare earth ions and transition metal ions as a luminescent center.

[0043] In general, the light absorption performance of activated semiconductor nanoparticles depends on the absorption coefficient of the host material. The chalcogenide perovskite, which is the host material 11 of the color conversion particles 10 of this embodiment, has a higher absorption coefficient than the host materials of conventional activated semiconductor nanoparticles. Therefore, the color conversion particles 10 of this embodiment have improved color conversion efficiency compared to conventional activated semiconductor nanoparticles. For example, when the color conversion particles 10 of this embodiment are applied to various devices such as display devices and lighting devices, it becomes easier to convert colors without transmitting blue excitation light. Furthermore, when the color conversion particles 10 of this embodiment are applied to various devices such as display devices and lighting devices, it becomes possible to thin the color conversion layer of the device, which is advantageous in terms of cost and manufacturing of the device.

[0044] Furthermore, the chalcogenide perovskite, which is the base material 11 of the color conversion particles 10 of this embodiment, has higher durability against heat and light than the base materials of conventional activated semiconductor nanoparticles. Therefore, the color conversion particles 10 of this embodiment have improved durability against high temperatures and light irradiation compared to conventional activated semiconductor nanoparticles. The color conversion particles 10 of this embodiment are also suitable for use in high-temperature and light-irradiated environments, such as during the operation of micro LEDs.

[0045] Furthermore, the chalcogenide perovskite, which is the base material 11 of the color conversion particles 10 of this embodiment, can be formed into nanoparticles by liquid-phase synthesis. Therefore, the color conversion particles 10 of this embodiment are also suitable for application to display devices, such as micro LEDs, which are becoming increasingly miniaturized.

[0046] <Product forms and application examples of Color Conversion Particles 10> Next, we will explain the product forms and application examples of the color-converting particles 10. Product forms of the color-converting particles 10 include powder, solution, thin film, and sheet. Furthermore, as an example of application of the color-converting particles 10, application to various devices is envisioned.

[0047] (powder) The powder is an aggregate of color conversion particles 10. Hereinafter, the color conversion particles 10 will be referred to as primary particles, and the aggregate of color conversion particles 10 will be referred to as secondary particles. There are no particular restrictions on the size of the primary particles and secondary particles, but primary particles are preferably in the range of 5 nm to 1000 nm. Ligands may also be attached to the surfaces of the primary particles and secondary particles. To improve properties such as luminescence characteristics, dispersibility of the color conversion particles, and film-forming properties, other materials may be added as additives to the powder of color conversion particles 10.

[0048] Furthermore, there are no particular limitations on the uses of the powder of color conversion particles 10. For example, they may be dispersed in a solvent to prepare a solution, dispersed in a resin or solid medium to prepare a composite, sintered to be used as a sputtering target, or used as a powder directly as a source for evaporation or the like.

[0049] (solution) The solution is a state in which the color conversion particles 10 are dispersed in a solvent. There are no particular restrictions on the size of the primary particles and secondary particles, but the primary particles are preferably in the range of 5 nm to 1000 nm. Furthermore, "dispersed" refers to a state in which the color conversion particles 10 are floating or suspended in the solvent, although some may have settled. Furthermore, ligands may be attached to the surfaces of the primary particles and secondary particles.

[0050] The solution may contain one or more solvents, including, but not limited to, the following: Water, esters such as methyl formate, ethyl formate, propyl formate, pentyl formate, methyl acetate, ethyl acetate, and pentyl acetate; ketones such as γ-butyrolactone, acetone, dimethyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone, and methylcyclohexanone; ethers such as diethyl ether, methyl tert-butyl ether, diisopropyl ether, dimethoxymethane, dimethoxyethane, 1,4-dioxane, 1,3-dioxolane, 4-methyldioxolane, tetrahydrofuran, methyltetrahydrofuran, anisole, and phenetole; methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, tert-butanol, 1-pentanol, 2-methyl-2-butanol, methoxypropanol, diacetone alcohol, cyclohexanol, 2-fluoroethanol, 2,2,2-trifluoroethanol, and 2,2,2-trifluoroethanol. alcohols such as ethanol and 2,2,3,3-tetrafluoro-1-propanol; glycol ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monoethyl ether acetate, and triethylene glycol dimethyl ether; organic solvents having an amide group such as N-methyl-2-pyrrolidone, N,N-dimethylformamide, acetamide, and N,N-dimethylacetamide; organic solvents having a nitrile group such as acetonitrile, isobutyronitrile, propionitrile, and methoxyacetonitrile; organic solvents having a carbonate group such as ethylene carbonate and propylene carbonate; organic solvents having a halogenated hydrocarbon group such as methylene chloride and chloroform; organic solvents having a hydrocarbon group such as n-pentane, cyclohexane, n-hexane, benzene, toluene, and xylene; dimethyl sulfoxide, etc.

[0051] In order to improve the light-emitting properties, dispersibility of the color conversion particles 10, film-forming properties, and other properties, an acid, a base, a binder material, or the like may be added as an additive to the above solution. The use of the solution is not particularly limited. For example, the solution may be used for film formation by a coating method, a spray method, a doctor blade method (or other solution film formation methods), for preparing a composite by combining with a solid dispersion medium, or for preparing a device using the same.

[0052] (thin film) The thin film is a state in which the color conversion particles 10 are aggregated in a planar form. There are no particular restrictions on the size of the primary particles and secondary particles, but the primary particles are preferably in the range of 5 nm to 1000 nm. Ligands may be attached to the surfaces of the primary particles and secondary particles. Other materials may be added to the thin film as additives to improve properties such as luminescence characteristics and dispersibility of the color conversion particles 10.

[0053] The method for producing the thin film is not particularly limited. For example, the thin film may be produced by coating, spraying, doctor blade, inkjet, or other solution film-forming methods, or by vacuum processes such as sputtering and vacuum deposition. Furthermore, the color-converting particles 10 may be formed into a film by coating or other methods, and then may be baked or otherwise treated to lose their particle shape.

[0054] (sheet) The sheet is a planar dispersion medium containing dispersed color conversion particles 10. There are no particular restrictions on the size of the primary particles and secondary particles, but the primary particles are preferably in the range of 5 nm to 1000 nm. Ligands may be attached to the surfaces of the primary particles and secondary particles.

[0055] The material used as the dispersion medium for the sheet can be any polymer known to those skilled in the art for such purposes. In a suitable embodiment, such polymers are substantially translucent or substantially transparent. For example, polymers that can be used as the dispersion medium for the sheet include, but are not limited to, polyvinyl butyral, polyvinyl acetate, silicones, and silicone derivatives, including, but not limited to, polyphenylmethylsiloxane, polyphenylalkylsiloxane, polydiphenylsiloxane, polydialkylsiloxane, fluorinated silicones, vinyl- and hydride-substituted silicones, ionomers, polyethylene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polypropylene, polyester, polycarbonate, polystyrene, polyacrylonitrile, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, ethylene-methacrylic acid copolymer film, nylon, and the like.

[0056] In order to improve properties such as the light emitting properties and the dispersibility of the color conversion particles 10, other materials such as silica fine particles or the solvents described above for the solution may be added to the sheet as additives. The method for producing the sheet is not particularly limited. For example, the sheet may be produced by kneading powder and a dispersion medium and stretching the mixture, or by mixing an ink containing the color-changing particles 10 with a dispersion medium or a precursor thereof and applying the mixture.

[0057] (device) The color conversion particles 10, or the above-mentioned powders, solutions, films, and sheets, can be used for down-conversion of ultraviolet light, blue light, etc. in various devices. Examples of such devices include light-emitting devices such as LEDs and organic ELs, display devices including such light-emitting devices, lighting devices including such light-emitting devices, image sensors, photoelectric conversion devices, and bioluminescent tags.

[0058] <Example> Examples of the color conversion particles of the present invention will now be described. The color conversion particles of the example have a base material of SrHfS3 and a dopant of Eu 3+ In the examples, color-converting particles were produced by solid-phase synthesis in the following manner.

[0059] First, 3.0 mmol of HfS2 raw material, 2.85 mmol of SrS raw material, and 0.15 mmol of EuCl3 raw material were crushed and mixed. Next, the mixture was placed in a bottomed cylindrical quartz tube, and the opening of the quartz tube was filled with quartz wool. The quartz tube was then placed in a metal ampoule. The metal ampoule was then fired in an electric furnace at 1100°C for 48 hours to obtain the color conversion particles of the present example.

[0060] Figure 2 is a graph showing the emission spectrum of the color conversion particles of the example. The horizontal axis of Figure 2 represents the emission wavelength, and the vertical axis of Figure 2 represents the normalized emission intensity. A laser light source with a wavelength of 532 nm was used as the excitation light.

[0061] It is known that the emission wavelength peak of SrHfS3, the base material of the color conversion particles of the example, is 2.32 eV (wavelength 534 nm). On the other hand, as shown in Figure 2, the color conversion particles of the example have an emission wavelength peak in the wavelength range of 600 nm to 700 nm, which is shifted to the longer wavelength side from the emission wavelength peak of the base material. Thus, the color conversion particles of the example have an emission wavelength peak of 2.32 eV (wavelength 534 nm). 3+ Red light emission (wavelength 630 nm) due to the above was confirmed.

[0062] Although the embodiments of the present invention have been described above, they are presented as examples and are not intended to limit the scope of the present invention. The embodiments can be implemented in various forms other than those described above, and various omissions, substitutions, modifications, etc. can be made without departing from the spirit of the present invention. The embodiments and their modifications are included within the scope and spirit of the present invention, and the inventions described in the claims and their equivalents are also included within the scope and spirit of the present invention. [Explanation of symbols]

[0063] 10...Color conversion particles 11…Material material 12...Dopant

Claims

1. the host material is a chalcogenide perovskite; Contains at least one dopant selected from rare earth ions and transition metal ions as a luminescent center Color transformation particles.

2. The chalcogenide perovskite may be a cubic perovskite, a tetragonal perovskite, or GdFeO 3 The perovskite has one of the following crystal structures: orthorhombic perovskite, Ruddlesden-Popper layered perovskite, Dion-Jacobson layered perovskite, or double perovskite. The color conversion particle according to claim 1 .

3. The chemical formula of the chalcogenide perovskite is ABX 3 or A' 2 A n-1 B n X 3n+1 (A and A' are elements of Group 2, B is an element of Group 4, and X is a chalcogen element, where n is an integer of 1 or more) The color conversion particle according to claim 2 .

4. The A, A', B, and X each include a mixture of elements from each group in any ratio. The color conversion particle according to claim 3 .

5. The chalcogenide perovskite is SrZrS 3 , SrZrSe 3 , SrHfS 3 , SrHfSe 3 , BaZrS 3 , BaZrSe 3 , BaHfS 3 , BaHfSe 3 , Sr 2 Ba n-1 Zr n S 3n+1 , Sr 2 Ba n-1 Zr n Se 3n+1 , Sr n+1 Zr n S 3n+1 , Sr n+1 Zr n Se 3n+1 , Ba 2 Sr n-1 Zr n S 3n+1 , Ba 2 Sr n-1 Zr n Se 3n+1 , Ba n+1 Zr n S 3n+1 , Ba n+1 Zr n Se 3n+1 , Sr 2 Ba n-1 Hf n S 3n+1 , Sr 2 Ba n-1 Hf n Se 3n+1 , Sr n+1 Hf n S 3n+1 , Sr n+1 Hf n Se 3n+1 , Ba 2 Sr n-1 Hf n S 3n+1 , Ba 2 Sr n-1 Hf n Se 3n+1 , Ba n+1 Hf n S 3n+1 , Ba n+1 Hf n Se 3n+1 (where n is an integer of 1 or more), The color conversion particle according to claim 1 .

6. The chalcogenide perovskite is (Sr x Ba 1-x ) (Zr y Hf 1-y ) (S z Se 1-z ) 3 or (Sr x’ Ba 1-x’ ) 2 (Sr x Ba 1-x ) n-1 (Zr y Hf 1-y ) n (S z Se 1-z ) 3n+1 (where x, x', y, and z are values ​​between 0 and 1) The color conversion particle according to claim 1 .

7. The chalcogenide perovskite has a structure in which a part of the elements constituting the chalcogenide perovskite is substituted with the dopant. The color conversion particle according to claim 1 .

8. The amount of dopant added to the base material is greater than 0 (at %) and equal to or less than 25 (at %). The color conversion particle according to claim 1 .

9. The amount of dopant added to the base material is 10 (at %) or less. The color conversion particle according to claim 8 .

10. The rare earth ion is Tm 3+ , Er 3+ , Pr 3+ , Dy 3+ , Ho 3+ , Tb 3+ , Sm 3+ , Eu 3+ , Eu 2+ , Ce 3+ is selected from either The color conversion particle according to claim 1 .

11. The transition metal ion is Co 3+ , Ni 2+ , Fe 3+ , Mn 5+ , Mn 4+ , Mn 3+ , Mn 2+ , Cr 4+ , Cr 3+ , V 5+ , V 4+ , V 3+ , Ti 4+ , Ti 3+ , Cu 2+ is selected from either The color conversion particle according to claim 1 .

12. The base material is SrHfS 3 and The dopant is Eu 3+ is The color conversion particle according to claim 1 .

13. The composition is (Sr 1-x , Eu x ) HfS 3 (where 0.01≦x≦0.10) The color conversion particle according to claim 12 .

14. A powder comprising the color conversion particles according to any one of claims 1 to 13.

15. A solution comprising the color conversion particles according to claim 1 .

16. A thin film comprising the color conversion particles according to any one of claims 1 to 13.

17. A sheet comprising the color conversion particles according to any one of claims 1 to 13.

18. A device comprising color conversion particles according to any one of claims 1 to 13.

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