Composite luminescent particles

Abstract

This invention provides a composite luminescent particle containing: (i) a first luminescent material which is a fluorescent material doped with a rare earth element, an s2-configured ion or a transition metal; (ii) a second luminescent material which is a fluorescent material doped with a rare earth element, an s2-configured ion or a transition metal; and (iii) a coating of an oxide material having a melting point of 700 °C or higher, wherein the oxide material is selected from the group consisting of silicon oxide, aluminum oxide, phosphate or magnesium oxide, and the D 50 value of the composite luminescent particle measured by a transmission electron microscope (TEM) is from 1 nm to 100 μm, and a method for producing the particle.

Description

Technical Field

[0001] The present invention relates to composite luminescent particles. Further, the present invention relates to a method for manufacturing the composite luminescent particles. Further, the present invention relates to a luminescent composition including a coating of the luminescent particles and a method for manufacturing the luminescent composition. Further, the present invention relates to a device including the composite luminescent particles or the luminescent composition of the present invention.

Background Art

[0002] Luminescent down-conversion materials play an important role in lighting, particularly in solid-state lighting devices for displays. Such materials can also be used, for example, as tags in security inks.

[0003] International Publication No. 2018 / 167266 discloses a composition including a luminescent substance and a sensitizing substance, where the luminescent substance and the sensitizing substance are selected such that the emission spectrum of the sensitizing substance at least partially overlaps with one or more of the excitation bands of the luminescent substance, and the luminescent substance and the sensitizing substance are arranged relative to each other such that non-radiative energy transfer from the sensitizing substance to the luminescent substance is enabled. This application also describes a method for manufacturing the same.

[0004] Non-radiative energy transfer from a sensitizing substance to a luminescent substance (also referred to as fluorescence resonance energy transfer, FRET) includes non-radiative transfer of energy from an excited sensitizing ion in a sensitizing material to an acceptor (or luminescent) ion in a luminescent material. This is evidenced by an increase in the emission from the luminescent substance ions in the luminescent material upon selective excitation of the sensitizing ions in the sensitizing material.

[0005] Nanomaterials are interesting because, due to their large surface area and small volume, luminescent substances can be spatially arranged in close proximity to utilize FRET between particles.

[0006] To effectively utilize FRET between particles, it is desirable that the size of the luminescent particles is very small (less than 10 nm). However, appropriate nanomaterials are small in size and low in crystallinity, so they may be of low quality (chemically, in terms of stability, optical and / or physical properties). This can be overcome by pre-firing or annealing the nanomaterials, but as a result, generally the particles become larger or aggregate. Such a mixture of large or aggregated particles is not good, and FRET between particles is poor. Annealing pre-mixed nanomaterials may result in quenching.

[0007] Therefore, there is still a need for luminescent nanomaterials that are small in size and have improved quality and stability. Furthermore, there is a need for luminescent compositions with high photoluminescence quantum yield (QY) and improved stability, and methods for producing the same. SUMMARY OF THE INVENTION

[0008] The present invention provides composite luminescent particles containing (i) a first luminescent material which is a fluorescent material doped with a rare earth element, an s2 configuration ion or a transition metal, (ii) a second luminescent material which is a fluorescent material doped with a rare earth element, an s2 configuration ion or a transition metal, and (iii) further containing a coating of an oxide material having a melting point of 700 °C or higher, wherein the oxide material is selected from the group consisting of silicon oxide, aluminum oxide, phosphate or magnesium oxide, and the D 50 value of the composite luminescent particles measured by a transmission electron microscope (TEM) is from 1 nm to 100 μm.

[0009] In the present invention, there is further provided a luminescent composition containing (i) a first luminescent material which is a fluorescent material doped with a rare earth element, an ion in the s2 configuration or a transition metal, and (ii) a second luminescent material which is a fluorescent material doped with a rare earth element, an ion in the s2 configuration or a transition metal, wherein at least one of the first luminescent material or the second luminescent material is (iii) coated with an oxide material having a melting point of 700 °C or higher, and the oxide material is selected from the group consisting of silicon oxide, aluminum oxide, phosphate or magnesium oxide, and the D 50 value of the coated material measured by a transmission electron microscope (TEM) is 1 nm or more and 100 μm or less.

[0010] The composite luminescent particles and luminescent composition of the present invention have good absorption and emission characteristics and a high photoluminescence quantum yield (QY). The luminescent composition or the particles of the present invention exhibit non-radiative energy transfer (also referred to as fluorescence resonance energy transfer, FRET). The composite luminescent particles also exhibit internal FRET.

[0011] An oxide material having a melting point of 700 °C or higher, which is selected from the group consisting of silicon oxide, aluminum oxide, phosphate or magnesium oxide and is used for encapsulation (e.g., silica), may improve the optical performance of the individual particles themselves. By adjusting the thickness of the shell, the IFRET performance of the material and thus the luminescence characteristics (e.g., excitation wavelength and emission wavelength) of the composite luminescent particles and luminescent composition can also be adjusted. Further, the oxide material may prevent the diffusion of ions between the luminescent materials. In certain embodiments, the oxide material may be doped with luminescent ions.

[0012] In the present invention, further, a) (i) A first luminescent material which is a fluorescent material doped with a rare earth element, an s2 configuration ion or a transition metal, or a precursor of the first luminescent material; (ii) preparing a second luminescent material which is a fluorescent material doped with a rare earth element, an s2 configuration ion or a transition metal, or a precursor of the second luminescent material; (iii) further preparing a precursor of an oxide material, wherein the melting point of the oxide material is at least 700 °C, and the oxide material is selected from the group consisting of silicon oxide, aluminum oxide, phosphate or magnesium oxide, b) Mixing the first luminescent material or its precursor, the second luminescent material or its precursor, and the precursor of the oxide material, c) Curing the precursor of the oxide material to obtain cured particles, the cured particles containing the first luminescent material or its precursor, the second luminescent material or its precursor, and a coating of the oxide material, and d) Heating the cured particles to at least 200 °C, A method for producing composite luminescent particles is provided, which includes the above steps.

[0013] By the method of the present invention, the composite luminescent particles of the present invention can be obtained.

[0014] Furthermore, a) (i) A first luminescent material which is a fluorescent material doped with a rare earth element, an s2 configuration ion or a transition metal, or a precursor of the first luminescent material; (ii) preparing a second luminescent material which is a fluorescent material doped with a rare earth element, an s2 configuration ion or a transition metal, or a precursor of the second luminescent material; (iii) further preparing a precursor of an oxide material, wherein the melting point of the oxide material is at least 700 °C, and the oxide material is selected from the group consisting of silicon oxide, aluminum oxide, phosphate or magnesium oxide, b) Mixing the second luminescent material or its precursor and the precursor of the oxide material, c) Curing the precursor of the oxide material to obtain cured particles, the cured particles containing the second luminescent material or its precursor and a coating of the oxide material, d) A step of mixing the hardening particles with the first luminescent material or a precursor thereof, where the first luminescent material or a precursor thereof is coated with an oxide material having a melting point of at least 700 °C as needed, and, e) A step of heating the mixture to at least 200 °C, A method for manufacturing a luminescent composition comprising is provided, wherein the first luminescent material can emit light in a first wavelength range, the second luminescent material can absorb light in a second wavelength range, and has an emission spectrum that at least partially overlaps with one or more of the excitation bands of the first luminescent material.

[0015] By the method of the present invention, the luminescent composition of the present invention can be obtained.

Brief Description of the Drawings

[0016]

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Mode for Carrying Out the Invention

[0017] Detailed Description of the Invention Composite Luminescent Nanoparticles (i) a first luminescent material which is a fluorescent material doped with a rare earth element, an s2-configured ion or a transition metal, (ii) a second luminescent material which is a fluorescent material doped with a rare earth element, an s2-configured ion or a transition metal, and (iii) a composite luminescent particle further containing a coating of an oxide material having a melting point of 700 °C or higher, wherein the oxide material is selected from the group consisting of silicon oxide, aluminum oxide, phosphate or magnesium oxide, and the D of the composite luminescent particles measured by a transmission electron microscope (TEM) 50Provided are composite light-emitting particles having a value of 1 nm or more and 100 μm or less. D 50 is defined as the median value of the lengths of the particles measured in a collection of at least 50 representative particles. The length is defined as the maximum diameter of the particle. The D of the composite light-emitting particles 50 value is measured including the coating.

[0018] The first light-emitting material and the second light-emitting material are fluorescent materials doped with rare earth elements, s2 configuration ions, or transition metals. In this disclosure, a fluorescent material doped with a rare earth element, an s2 configuration ion, or a transition metal is a material capable of emitting light, that is, a material that emits light when exposed to a certain kind of radiation energy and doped with a rare earth metal, an s2 configuration ion, or a transition metal ion. As is known to those skilled in the art, a rare earth-doped fluorescent material includes a host lattice doped with optically active ions. Rare earth metal ions are defined in this specification as ions of yttrium, scandium, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium. Transition metal ions are defined in this specification as ions in the d-block of the periodic table, and s2 configuration ions are defined as ions with an s2 electron configuration. Examples of s2 configuration ions are Ge 2+ , Pb 2+ and Bi 3+ are.

[0019] Preferably, the light-emitting material is doped with at least one trivalent ion of cerium, europium, or terbium. These ions are attractive as lighting because they can emit light in the visible spectrum with appropriate excitation.

[0020] Preferably, the luminescent material is selected from the group consisting of oxides, fluorides, nitrides, borates, garnets, molybdates, phosphates, vanadates, chlorides, sulfides, selenides, silicates, aluminates, oxyfluorides, oxychlorides, oxynitrides,oxysulfides,oxyselenides, fluorochlorides, fluorosilicates, and fluorobromides, or combinations thereof. These materials form lattices that can be doped with rare earth metal ions.

[0021] More preferably, the luminescent material is selected from the group consisting of oxides, garnets, phosphates, vanadates, or combinations thereof. Even more preferably, the luminescent material is Y3Al5O 12 , Lu3Al5O 12 , Y2O3, YVPO4, YVO4, or LaPO4, or combinations thereof. These luminescent materials have been found to exhibit desirable optical properties.

[0022] Preferably, the first luminescent material is an oxide, and the second luminescent material is also an oxide.

[0023] Preferably, the first luminescent material is (Lu,Y)3Al5O 12 :Eu 3+ , Y2O3:Eu 3+ , and optionally doped with Tb 3+ . These materials are stable and exhibit strong europium luminescence.

[0024] Preferably, the second luminescent material is Y3Al5O 12 :Ce 3+ , Lu3Al5O 12 :Ce 3+ , and optionally doped with Tb 3+ . These materials are stable and exhibit strong cerium luminescence and can be excited by blue light.

[0025] In another preferred embodiment, one of the luminescent materials is a phosphate and the remaining luminescent material is an oxide. More preferably, the first luminescent material is Y2O3:Eu3+ wherein the second luminescent material is LaPO4:Tb 3+ is provided.

[0026] The composite luminescent particles further contain a coating of an oxide material having a melting point of 700 °C or higher. The oxide material forms a coating around the first luminescent material and the second luminescent material. This protects the luminescent material from degradation due to, for example, moisture or heat.

[0027] The melting point of the oxide material is 700 °C or higher. Preferably, the melting point is 900 °C or higher, more preferably 1200 °C or higher. Because of the high melting point, the composite luminescent particles can be processed, for example, by annealing the luminescent material without melting or aggregating. Therefore, the melting point of the oxide material is preferably higher than the lowest melting point of the luminescent material.

[0028] The oxide material is selected from the group consisting of silicon oxide, aluminum oxide, or phosphate. More preferably, the oxide material is selected from the group consisting of silica, alumina, magnesium oxide, and phosphate. These materials are physically, chemically, and thermally stable. Preferably, the second material is silica, and the stability of this material is good. Since silica can be easily dispersed in water or other hydrophilic solvents, the composite luminescent particles are suitable for various applications. In certain embodiments, the oxide material may be doped with luminescent ions.

[0029] Preferably, the first luminescent material can emit light in a first wavelength range, the second luminescent material can absorb light in a second wavelength range, and has an emission spectrum that at least partially overlaps with one or more of the excitation bands of the first luminescent material. Such composite luminescent particles can exhibit FRET between the two materials.

[0030] More preferably, the first luminescent material and the second luminescent material are arranged relative to each other such that non-radiative energy transfer from the second luminescent material to the first luminescent material is enabled.

[0031] Preferably, the first luminescent material and the second luminescent material form respective regions inside the oxide material, where the regions have a bulk, and D is the minimum dimension of the regions measured by a transmission electron microscope (TEM). 50 The value of D is 0.5 nm or more and 100 nm or less, more preferably 0.5 nm or more and 50 nm or less, and most preferably 0.5 nm or more and 10 nm or less. Preferably, the D 50 The value of is 0.5 nm or more and 100 nm or less, more preferably 0.5 nm or more and 50 nm or less, and most preferably 0.5 nm or more and 10 nm or less. Therefore, the coating of the oxide material is not included in the size of the regions. Regions of such a size are suitable for FRET. Such small regions are desirable because they have a large surface area. The oxide material forms a stable matrix around the regions to prevent ion exchange and quenching. Further, the oxide material maintains the regions in place so that the distance between the regions is the same regardless of post-treatment.

[0032] Preferably, D of the composite luminescent particles measured by a transmission electron microscope (TEM) 50 The value is 1 nm or more and 50 μm or less. The D 50 The value measured by a transmission electron microscope (TEM) is more preferably 20 nm or more and 10 μm or less, and most preferably 50 nm or more and 10 μm or less. When the bulk of the particles of the first luminescent material and the second luminescent material is small, not only is FRET between the particles possible, but also the coating of the oxide material becomes thinner, so the distance between the luminescent materials also becomes shorter. The smaller the particles, the larger the surface area, which may be desirable.

[0033] Luminescent Composition Furthermore, there is provided a luminescent composition including (i) a first luminescent material which is a fluorescent material doped with a rare earth element, an s2 configuration ion or a transition metal, and (ii) a second luminescent material which is a fluorescent material doped with a rare earth element, an s2 configuration ion or a transition metal. Here, at least one of the first luminescent material or the second luminescent material is coated with an oxide material having a melting point of 700 °C or higher, and the oxide material is selected from the group consisting of silicon oxide, aluminum oxide, phosphate, or magnesium oxide, and D of the coated particles measured by a transmission electron microscope (TEM) 50 The value is 1 nm or more and 100 μm or less.

[0034] Preferably, the first luminescent material can emit light in a first wavelength range, the second luminescent material can absorb light in a second wavelength range, and has an emission spectrum that at least partially overlaps with one or more of the excitation bands of the first luminescent material.

[0035] More preferably, the first luminescent material and the second luminescent material are arranged relative to each other so as to enable non-radiative energy transfer from the second luminescent material to the first luminescent material.

[0036] In one aspect, the luminescent composition includes the first luminescent material as particles coated with an oxide material and the second luminescent material as particles coated with an oxide material. Due to the oxide material coating the first luminescent material and the second luminescent material, the luminescent particles are well mixed and the luminescent composition is homogeneous. Such a structure is shown in FIG. 1c.

[0037] In one aspect, only one of the first luminescent material or the second luminescent material is included in particles coated with an oxide material. In this case, preferably, D of the minimum dimension of the remaining luminescent material measured by a transmission electron microscope (TEM) 50 The value is preferably 0.5 nm or more and 100 nm or less, more preferably 0.5 nm or more and 50 nm or less, and most preferably 0.5 nm or more and 10 nm or less. Preferably, D of the remaining luminescent material 50The value is 0.5 nm or more and 100 nm or less, more preferably 0.5 nm or more and 50 nm or less, and most preferably 0.5 nm or more and 10 nm or less. In another aspect, the remaining luminescent material is provided as a bulk material together with coated particles provided on the bulk luminescent material. In this specification, the term "bulk" means, in particular, something larger than the nanoscale, for example, including those with a diameter exceeding 100 nm and having a micro-sized scale, and / or including.

[0038] First Luminescent Material and Second Luminescent Material Preferably, the first luminescent material can emit light in a first wavelength range, the second luminescent material can absorb light in a second wavelength range, and has an emission spectrum that at least partially overlaps with one or more of the excitation bands of the first luminescent material. In all aspects corresponding to this, the following applies.

[0039] The first luminescent material may be able to emit light in a first wavelength range. Those skilled in the art will understand that in the luminescent composition of the present invention, the first luminescent material functions as a luminescent substance. The first wavelength range may be any wavelength range of interest. Preferred wavelength ranges will be described below.

[0040] The second luminescent material may be able to absorb light in a second wavelength range. Those skilled in the art will understand that in the luminescent composition of the present invention, the second luminescent material functions as a sensitizing substance. The second wavelength range may be any wavelength range of interest. Preferred wavelength ranges will be described below.

[0041] When the second luminescent material is excited by light in the second wavelength range, it has an emission spectrum that at least partially overlaps with one or more of the excitation bands of the first luminescent material. Those skilled in the art can sufficiently determine the spectral overlap based on spectra known in the art or by determining the spectrum through routine experiments disclosed, for example, in WO 2020 / 053429.

[0042] Preferably, at least one of the overlap of the emission spectrum of the second material and the excitation band of the first material is in a wavelength range of blue (440 to 480 nm), green (510 to 560 nm), or yellow (560 to 580 nm).

[0043] Preferably, the first luminescent material and the second luminescent material are arranged relative to each other such that non-radiative energy transfer (also referred to as fluorescence resonance energy transfer, FRET) from the second luminescent material (sensitizer) to the first luminescent material (emitter) is possible. Generally, this includes proximity between the first luminescent material and the second luminescent material, for example, a distance of about 0.5 nm to about 20 nm. Those skilled in the art are well aware of how non-radiative energy transfer is achieved. This is described, for example, in International Publication No. 2018 / 167266, the content of which is incorporated herein by reference. Those skilled in the art understand that non-radiative energy transfer includes non-radiative transfer of energy from an excited sensitizer to a receptor (or emitter) in the luminescent material. This is demonstrated by the fact that an increase in the selective excitation of the sensitizing material increases the emission from the luminescent ions in the luminescent material. This non-radiative energy transfer may be due to either Förster-type or Dexter-type energy transfer. Since resonance energy transfer is inversely proportional to the sixth power of the interionic distance (in the case of Förster-type energy transfer) or exponentially proportional to that distance (in the case of Dexter-type energy transfer), those skilled in the art understand that an arrangement that enables non-radiative energy transfer can be achieved by appropriately designing the effective distance between the sensitizing material and the luminescent ions in the luminescent material.

[0044] Those skilled in the art understand that for FRET to occur, the first material and the second material need to be in proximity.

[0045] The first luminescent material The first luminescent material can emit light in a first wavelength range. The first wavelength range can be any wavelength range of interest.

[0046] Preferably, the first luminescent material contains a red or green luminescent substance. In this specification, the term "red luminescent substance" refers to a substance having one or more emission bands at 600 nm to 700 nm upon appropriate excitation, and the term "green luminescent substance" refers to a substance having one or more emission bands at 510 to 560 nm upon appropriate excitation. Providing a red or green luminescent substance may be desirable for color rendering. According to another aspect of the present invention, the first luminescent material is a material having one or more emission bands at 700 to 1400 nm (IR-A), 580 to 600 nm (amber and / or orange), 560 to 580 nm (yellow), 480 to 510 nm (cyan), 440 to 480 nm (blue), 400 to 440 nm (violet), 315 to 400 nm (UV-A) and / or 280 to 315 nm (UV-B) upon appropriate excitation.

[0047] The first luminescent material includes a fluorescent material doped with a rare earth element, an s2 configuration ion or a transition metal. The fluorescent material may be a phosphor doped with a divalent or trivalent rare earth element. Examples of fluorescent materials doped with appropriate rare earth elements include, but are not limited to, LaPO4:Eu 3+ (and / or Tb 3+ ), CaAlSiN3:Eu 2+ , Y2O3:Eu 3+ (and / or Tb 3+ ), Y(V,P)O4:Eu 3+ (and / or Tb 3+ ), Lu3Al5O 12 :Ce 3+ (or Eu 3+ and / or Tb 3+ ), Y3Al5O 12 :Ce 3+ (or Eu 3+ and / or Tb 3+ ) and combinations thereof are included, and examples of phosphors doped with appropriate transition metals are BaMgAl 14 O 23 :Mn 2+ , Mg(Al,Ga)2O4:Mn 2+ , Zn2SiO4:Mn 2+ , K2SiF6:Mn 4+ , MgF2.GeO2:Mn4+ and combinations thereof.

[0048] The fluorescent material may be currently available on the market or may be synthesized, for example, as described in Riwotzki, K.; Meyssamy, H.; Kornowski, A.; Haase, M. J. Phys. Chem. B. 2000, 104, 2824-2828.

[0049] As is known to those skilled in the art, fluorescent materials doped with rare earth elements, s2 configuration ions or transition metals contain a host lattice doped with optically active ions.

[0050] The host lattice of the preferred first luminescent material is doped with one or more ions selected from the group consisting of Eu 3+ , Tb 3+ , Mn 2+ and Mn 4+ . These ions provide good luminescence properties such as strong emission bands and / or emission bands in the red or green part of the visible spectrum.

[0051] In the case of doping with Eu 3+ , the first luminescent material may have, for example, a host lattice doped with a doping rate of at least about 1%, more preferably a doping rate of about 5% to about 80%. In the case of doping with Tb 3+ , the first luminescent material may have, for example, a host lattice doped with a doping rate of at least about 10%, more preferably a doping rate of about 30% to about 80% of Tb 3+ . In the case of doping with Mn 4+ , the first luminescent material may have, for example, a host lattice doped with a doping rate of at least about 0.1 to 30%, most preferably about 1 to 10%. In the case of doping with Mn 2+ , the first luminescent material may have, for example, a host lattice doped with a doping rate of at least about 0.1 to 30%, most preferably about 1 to 10%.

[0052] In a representative embodiment, the first luminescent material is (Ca,Sr)Ga2O6:Eu 3+ (or Tb 3+ ), (Ca,Sr,Ba)La2Bi2(SiO4)3O:Eu 3+ (or Tb 3+ ), (Ca,Sr,Ba)SnO3:Eu 3+ (and / or Tb 3+ ), (Ca,Y,Gd)MoO4:Eu 3+ (or Tb 3+ ), (Y,Gd)BO3 (pseudo-betafite):Eu 3+ (or Tb 3+ ), (Y,Tb)SiO5:Eu 3+ (or Tb 3+ ), A-La2O3:Eu 3+ (or Tb 3+ ), Ba2(SiO4):O 2- :Eu 3+ (or Tb 3+ ), Ba2MgSi2O7:Eu 3+ (or Tb 3+ ), Ba2Y(BO3)2Cl:Eu 3+ (or Tb 3+ ), Ba3(PO4)2:Eu 3+ (or Tb 3+ ), Ba3Ca3(PO4)4:Eu 3+ (or Tb 3+ ), Ba3Gd(BO3)3:Eu 3+ (or Tb 3+ ), Ba3Gd2(BO3)4:Eu 3+ (or Tb 3+ ), Ba3La2(BO3)4:Eu 3+ (or Tb 3+ ), Ba3V2O8:Eu 3+ (or Tb 3+ ), Ba3Y2(BO3)4:Eu 3+ (or Tb 3+ ), BaB8O 13 :Eu 3+ (or Tb 3+ ), BaBPO5:Eu 3+ (or Tb 3+ ), BaFCl:Eu 3+ (or Tb 3+)、BaGd2O4:Eu 3+ (or Tb 3+ )、BaGd4Si5O 17 :Sm:Eu 3+ (or Tb 3+ )、BaGdB9O 16 :Eu 3+ (or Tb 3+ )、BaLaB9O 16 :Eu 3+ (or Tb 3+ )、BaSO4:Eu 3+ (or Tb 3+ )、BaY2F8:Yb:Eu 3+ (or Tb 3+ )、BaY2Si3O 10 :Eu 3+ (or Tb 3+ )、BaYB9O 16 :Eu 3+ (or Tb 3+ )、BaZr(BO3)2:Eu 3+ (or Tb 3+ )、BaZrO3:Eu 3+ (or Tb 3+ )、BaZrO3:Eu 3+ (or Tb 3+ )、b-BaB2O4:Eu 3+ (or Tb 3+ )、B-Gd2O3:Eu 3+ (or Tb 3+ )、Ca2Al(AlSiO7):Eu 3+ (or Tb 3+ )、Ca2Gd2(GeO4)2O:Eu 3+ (or Tb 3+ )、Ca2Gd8(SiO4)6O2:Eu 3+ (or Tb 3+ )、Ca2Gd8Si6O 26 :Eu 3+ (or Tb 3+ )、Ca2La8(SiO4)6O2:Eu 3+ (or Tb 3+ )、Ca3(BO3)2:Eu 3+ (or Tb 3+ )、Ca3Al2O6:Eu 3+ (or Tb 3+ )、Ca3Gd2(BO3)4:Eu3+ (or Tb 3+ ), Ca3La2(BO3)4:Eu 3+ (or Tb 3+ ), Ca3Y2(BO3)4:Eu 3+ (or Tb 3+ ), Ca4GdO(BO3)3:Eu 3+ (or Tb 3+ ), Ca5(PO 11 )3F:Eu 3+ (or Tb 3+ ), Ca5(PO4)3Br:Eu 3+ (or Tb 3+ ), Ca5(PO4)3F:(4f-site):Eu 3+ (or Tb 3+ ), Ca5(PO4)3F:(6h-site):Eu 3+ (or Tb 3+ ), Ca5(PO4)3OH:Eu 3+ (or Tb 3+ ), CaBPO5:Eu 3+ (or Tb 3+ ), CaF2:Eu 3+ (or Tb 3+ ), CaLaB7O 13 :Eu 3+ (or Tb 3+ ), calcite - CaCO3:Eu 3+ (or Tb 3+ ), CaO:Eu 3+ (or Tb 3+ ), CaSO4:Eu 3+ (or Tb 3+ ), CaYO(BO3):Eu 3+ (or Tb 3+ ), C - Gd2O3:Eu 3+ (or Tb 3+ ), C - Lu2O3:(C2):Eu 3+ (or Tb 3+ ), C - Lu2O3:(C3i):Eu 3+ (or Tb 3+ ), Cs2NaYF6:Tm:Eu 3+ (or Tb 3+ ), Cs3Ge3O9:Eu 3+ , C - Sc2O3:Yb:Eu 3+ (or Tb 3+)、C-Y2O3:Eu 3+ (or Tb 3+ )、Eu 3+ (or Tb 3+ )[(ttfa)3(phen)]0:Eu 3+ (or Tb 3+ )、Gd 17.33 (BO3)4(B2O5)2O 16 :Eu 3+ (or Tb 3+ )、Gd2BaZnO5:Eu 3+ (or Tb 3+ )、Gd2O2(SO4):Eu 3+ (or Tb 3+ )、Gd2P4O 13 :Eu 3+ (or Tb 3+ )、Gd3O4Br:Eu 3+ (or Tb 3+ )、Gd3PO7:Eu 3+ (or Tb 3+ )、Gd3Te2Li3O 12 :Eu 3+ (or Tb 3+ )、Gd8P2O 17 :Eu 3+ (or Tb 3+ )、GdA l3 (BO3)4:Eu 3+ (or Tb 3+ )、GdAlO3:Eu 3+ (or Tb 3+ )、GdAlO3:Eu 3+ (or Tb 3+ )、GdB3O6:Eu 3+ (or Tb 3+ )、GdBO3:Eu 3+ (or Tb 3+ )、GdGaO3:Eu 3+ (or Tb 3+ )、GdOBr:Eu 3+ (or Tb 3+ )、GdOCl:Eu 3+ (or Tb 3+ )、GdP3O9:Eu 3+ (or Tb 3+ )、GdPO4:Eu 3+ (or Tb 3+ )、I-CaB2O4:Eu3+ (or Tb 3+ )、InBO3:Eu 3+ (or Tb 3+ )、I-SrB2O4:Eu 3+ (or Tb 3+ )、KCaGd(PO4)2:Eu 3+ (or Tb 3+ )、La 26 O 27 (BO3)8:Eu 3+ (or Tb 3+ )、La2BaZnO5:Eu 3+ (or Tb 3+ )、La2Hf2O7:Eu 3+ (or Tb 3+ )、La2O2(SO4):Eu 3+ (or Tb 3+ )、La2O2S:Eu 3+ (or Tb 3+ )、La2W3O 12 :Eu 3+ (or Tb 3+ )、La2Zr3(MoO4)9:Eu 3+ (or Tb 3+ )、La3TaO4Cl6:Eu 3+ (or Tb 3+ )、La3WO6Cl3:Eu 3+ (or Tb 3+ )、LaAlO3:Eu 3+ (or Tb 3+ )、LaB3O6:Eu 3+ (or Tb 3+ )、LaBO3:Eu 3+ (or Tb 3+ )、LaF3:Eu 3+ (or Tb 3+ )、LaGaO3:Eu 3+ (or Tb 3+ )、LaMgB5O 10 :Eu 3+ (or Tb 3+ )、LaOBr:Eu 3+ (or Tb 3+ )、LaOCl:Eu 3+ (or Tb 3+ )、LaOF:Eu 3+ (or Tb 3+ )、LaOI:Eu3+ (or Tb 3+ ), LaP3O9:Eu 3+ (or Tb 3+ ), LaPO4:Eu 3+ (or Tb 3+ ), LaYO3:Eu 3+ (or Tb 3+ ), Li2Lu5O4(BO3)3:Eu 3+ (or Tb 3+ ), Li3Ba2La3( MoO4)8:Eu 3+ (or Tb 3+ ), Li3La2(BO3)3:Eu 3+ (or Tb 3+ ), Li6Gd(BO3)3:Eu 3+ (or Tb 3+ ), Li6Y(BO3)3:Eu 3+ (or Tb 3+ ), LiCaAlF6:Eu 3+ (or Tb 3+ ), LiEu 3+ (or Tb 3+ ), Mo2O8:Eu 3+ (or Tb 3+ ), LiGd6O5(BO3)3:Eu 3+ (or Tb 3+ ), LiGdF4:Eu 3+ (or Tb 3+ ), LiGdGeO4:Eu 3+ (or Tb 3+ ), LiGdO2:Eu 3+ (or Tb 3+ ), LiGdSiO4:Eu 3+ (or Tb 3+ ), LiLa2O2BO3:Eu 3+ (or Tb 3+ ), LiLaGeO4:Eu 3+ (or Tb 3+ ), LiLaO2:Eu 3+ (or Tb 3+ ), LiLaP4O 12 :Eu 3+ (or Tb 3+ ), LiLaSiO4:Eu 3+ (or Tb 3+ ), LiLuGeO4:Eu3+ (or Tb 3+ ), LiLuO2:Eu 3+ (or Tb 3+ ), LiLuSiO4:Eu 3+ (or Tb 3+ ), LiScO2:Eu 3+ (or Tb 3+ ), LiSr2YO4:Eu 3+ (or Tb 3+ ), LiSrAlF6:Eu 3+ (or Tb 3+ ), LiY6O5(BO3)3:Eu 3+ (or Tb 3+ ), LiYF4:Eu 3+ (or Tb 3+ ), LiYGeO4:Eu 3+ (or Tb 3+ ), LiYO2:Eu 3+ (or Tb 3+ ), LiYSiO4:Eu 3+ (or Tb 3+ ), Lu2O2(SO4):Eu 3+ (or Tb 3+ ), Lu2Si2O7:Eu 3+ (or Tb 3+ ), Lu3Al5O 12 :Eu 3+ (or Tb 3+ ), Lu3Al5O 12 :Yb:Eu 3+ (or Tb 3+ ), LuBO3:Eu 3+ (or Tb 3+ ), LuBO3(calcite):Eu 3+ (or Tb 3+ ), LuOCl:Eu 3+ (or Tb 3+ ), LuPO4:Eu 3+ (or Tb 3+ ), Mg2Gd8(SiO4)6O2:Eu 3+ (or Tb 3+ ), Mg2La8(SiO4)6O2:Eu 3+ (or Tb 3+ ), MgO:Eu 3+ (or Tb 3+ ), MgSiO3:Eu 3+(or Tb 3+ ), Na3YSi3O9:Eu 3+ (or Tb 3+ ), Na6Gd(BO3)3:Eu 3+ (or Tb 3+ ), NaGdGeO4:Eu 3+ (or Tb 3+ ), NaGdO2:Eu 3+ (or Tb 3+ ), NaGdSiO4:Eu 3+ (or Tb 3+ ), NaLaGeO4:Eu 3+ (or Tb 3+ ), NaLaO2:Eu 3+ (or Tb 3+ ), NaLaSiO4:Eu 3+ (or Tb 3+ ), NaLuGeO4:Eu 3+ (or Tb 3+ ), NaLuSiO4:Eu 3+ (or Tb 3+ ), NaScO2:Eu 3+ (or Tb 3+ ), NaSrLa(VO4)2:Eu 3+ (or Tb 3+ ), NaYGeO4:Eu 3+ (or Tb 3+ ), NaYSiO4:Eu 3+ (or Tb 3+ ), ScBO3:Eu 3+ (or Tb 3+ ), ScOCl:Eu 3+ (or Tb 3+ ), ScPO4:Eu 3+ (or Tb 3+ ), Sr2B2O5:Eu 3+ (or Tb 3+ ), Sr2Gd8(SiO4)6O2:Eu 3+ (or Tb 3+ ), Sr2La2Zn2O7:Eu 3+ (or Tb 3+ ), Sr2La2Zn2O7:Eu 3+ (or Tb 3+ ), Sr2LaAlO5:Eu 3+ (or Tb 3+)、Sr3(BO3)2:Eu 3+ (or Tb 3+ )、Sr3(PO4)2:Eu 3+ (or Tb 3+ )、Sr3(PO4)2:Sm:Eu 3+ (or Tb 3+ )、Sr3Gd2(BO3)4:Eu 3+ (or Tb 3+ )、Sr3La2(BO3)4:Eu 3+ (or Tb 3+ )、Sr3La6(SiO4)6:Eu 3+ (or Tb 3+ )、Sr3Y2(BO3)4:Eu 3+ (or Tb 3+ )、Sr5(PO4)3F:Eu 3+ (or Tb 3+ )、Sr9Ln(VO4)7:Eu 3+ (or Tb 3+ )、SrAl2B2O7:Eu 3+ (or Tb 3+ )、SrB4O7:Eu 3+ (or Tb 3+ )、SrB6O 10 :Eu 3+ (or Tb 3+ )、SrCO3:Eu 3+ (or Tb 3+ )、SrGdAlO4:Eu 3+ (or Tb 3+ )、SrHfO3:Tm:Eu 3+ (or Tb 3+ )、SrLa2BeO5:(4c):Eu 3+ (or Tb 3+ )、SrLa2BeO5:(8d):Eu 3+ (or Tb 3+ )、SrLaAlO4:Eu 3+ (or Tb 3+ )、SrLaGa3O7:Eu 3+ (or Tb 3+ )、SrLaO(BO3):Eu 3+ (or Tb 3+ )、SrO:Eu 3+ (or Tb 3+ )、SrY2O4:(Sr-site):Eu 3+(or Tb 3+ )、SrY2O4:(Y-site1):Eu 3+ (or Tb 3+ )、SrY2O4:(Y-site2):Eu 3+ (or Tb 3+ )、Tb2Mo3O 12 :Eu 3+ (or Tb 3+ )、Tb2W3O 12 :Eu 3+ (or Tb 3+ )、TbBO3:Eu 3+ (or Tb 3+ )、ThO2:Eu 3+ (or Tb 3+ )、X1-Gd2SiO5:Eu 3+ (or Tb 3+ )、X1-Y2SiO5:Eu 3+ (or Tb 3+ )、X2-Y2SiO5:Eu 3+ (or Tb 3+ )、Y 17.33 (BO3)4(B2O5)2O 16 :Eu 3+ (or Tb 3+ )、Y2Ge2O7:Eu 3+ (or Tb 3+ )、Y2GeO5:Eu 3+ (or Tb 3+ )、Y2O2(SO4):Eu 3+ (or Tb 3+ )、Y2O2S:Eu 3+ (or Tb 3+ )、Y2O2S:Eu 3+ (or Tb 3+ )、Y2O3:Eu 3+ (or Tb 3+ )、Y2P4O 13 :Eu 3+ (or Tb 3+ )、Y2Si2O7:Eu 3+ (or Tb 3+ )、Y2SiO5:Eu 3+ (or Tb 3+ )、Y3Al5O 12 :Eu 3+ (or Tb 3+ )、Y3O4Br:Eu 3+(or Tb 3+ )、Y3O4Cl:Eu 3+ (or Tb 3+ )、Y3PO7:Eu 3+ (or Tb 3+ )、Y4GeO8:Eu 3+ (or Tb 3+ )、Y8P2O 17 :Eu 3+ (or Tb 3+ )、YAl3(BO3)4:Eu 3+ (or Tb 3+ )、YAlO3:Eu 3+ (or Tb 3+ )、YBO3:Eu 3+ (or Tb 3+ )、YbOBr:Yb:Eu 3+ (or Tb 3+ )、YF3:Eu 3+ (or Tb 3+ )、YOBr:Eu 3+ (or Tb 3+ )、YOCl:Eu 3+ (or Tb 3+ )、YOCl :Eu 3+ (or Tb 3+ )、YOF:Eu 3+ (or Tb 3+ )、YOF:Eu 3+ (or Tb 3+ )、YP3O9:Eu 3+ (or Tb 3+ )、YPO4:Eu 3+ (or Tb 3+ )、YTaO4:Eu 3+ (or Tb 3+ )、YVO4:Eu 3+ (or Tb 3+ )、ZrP2O7:Eu 3+ (or Tb 3+ )、Y3Al5O 12 :Ce 3+ 、Lu3Al5O 12 :Ce 3+ is selected from the group consisting of or a mixture thereof.

[0053] Those skilled in the art will understand that :Eu 3+ (:Tb 3+ 、:Ce3+ , : Mn 2+ or: Mn 4+ ) The notation indicates that the host lattice is Eu 3+ (Tb 3+ , Ce 3+ , Mn 2+ or Mn 4+ ) and is understood to be doped with it.

[0054] Second luminescent material A suitable inorganic luminescent material may be used as the second luminescent material. The second material can absorb light in the second wavelength range. The second wavelength range may be any wavelength range of interest.

[0055] Preferably, the second luminescent material has one or more excitation bands at wavelengths of 300 to 580 nm, and preferably, the second luminescent material has one or more excitation bands in UV-A (315 to 400 nm), violet (400 to 440 nm), blue (440 to 490 nm) or green (510 to 560 nm), most preferably blue (440 to 490 nm). LEDs based on (Al, In, Ga)N generate efficient "pump" light at violet to blue wavelengths (about 400 nm to about 490 nm). Examples of blue excitation materials are CaAlSiN3:Eu 2+ and Y3Al5O 12 : Ce 3+ are.

[0056] In another aspect of the present invention, the second luminescent material is a material having one or more excitation bands in 700 to 1400 nm (IR-A), 580 to 600 nm (amber and / or orange), 560 to 580 nm (yellow), 510 to 560 nm (green), 480 to 510 nm (cyan), 440 to 480 nm (blue), 400 to 440 nm (violet), 315 to 400 nm (UV-A) and / or 280 to 315 nm (UV-B).

[0057] In another preferred embodiment, the host lattice of the second luminescent material is garnet, fluoride, silicate, phosphate or nitride, more preferably Y3Al5O 12 (YAG), Lu3Al5O 12Selected from the group consisting of (LuAG), LaPO4, MgF2, CaF2, Sr2SiO4, Ba2SiO4, Ca2MgSi2O7, LiSrPO4, CaAlSiN3, or combinations thereof. Preferably, the host lattice of the preferred second luminescent material is Eu 2+ , Pb 2+ , Bi 3+ and Ce 3+ doped with one or more ions selected from the group consisting of, more preferably Eu 3+ in combination with Tb 2+ or Ce 3+ , and most preferably Ce 3+ in combination with Tb 3+ .

[0058] Preferably, the host lattice of the second luminescent material or its precursor is a garnet, such as Y3Al5O 12 (YAG) or Lu3Al5O 12 (LuAG) or a combination thereof. Most preferably, the host lattice is selected from the group consisting of Y3Al5O 12 (YAG) or Lu3Al5O 12 (LuAG) or a combination thereof, and the dopant optionally includes Ce 3+ in combination with Tb 3+ .

[0059] Preferably, in the case of doping with Ce 3+ , the second luminescent material has a host lattice doped at a doping rate of 0.05 - 5%, more preferably 0.1 - 4%.

[0060] Method for Producing Composite Luminescent Particles Furthermore, a method for manufacturing composite luminescent particles is provided. This method is a) (i) A first luminescent material which is a fluorescent material doped with a rare earth element, an ion in s2 configuration or a transition metal, or a precursor of the first luminescent material; (ii) A second luminescent material which is a fluorescent material doped with a rare earth element, an ion in s2 configuration or a transition metal, or a precursor of the second luminescent material; (iii) Further preparing a precursor of an oxide material, wherein the melting point of the oxide material is at least 700 °C, and the oxide material is selected from the group consisting of silicon oxide, aluminum oxide, phosphate or magnesium oxide, b) Mixing the first luminescent material or its precursor, the second luminescent material or its precursor, and the precursor of the oxide material, c) Curing the precursor of the oxide material to obtain cured particles, the cured particles containing the first luminescent material or its precursor, the second luminescent material or its precursor, and a coating of the oxide material, and d) Heating the cured particles to at least 200 °C, including.

[0061] This method enables the production of the composite luminescent particles of the present invention.

[0062] Step a) includes (i) a first luminescent material which is a fluorescent material doped with a rare earth element, an ion in s2 configuration or a transition metal, or a precursor of the first luminescent material; (ii) a second luminescent material which is a fluorescent material doped with a rare earth element, an ion in s2 configuration or a transition metal, or a precursor of the second luminescent material; (iii) further preparing a precursor of an oxide material, wherein the melting point of the oxide material is at least 700 °C, and the oxide material is selected from the group consisting of silicon oxide, aluminum oxide, phosphate or magnesium oxide.

[0063] The luminescent material is a fluorescent material doped with the above rare earth element, ion in s2 configuration or transition metal.

[0064] Preferably, the luminescent material or its precursor is provided as particles, and the minimum dimension D of the particles 50The value is 0.5 nm or more and 100 nm or less. Thereby, a region is formed within the matrix of the oxide material.

[0065] Preferably, D, the minimum dimension of the particles of the luminescent material or its precursor, measured by a transmission electron microscope (TEM) 50 The value is 0.5 nm or more and 50 nm or less, more preferably 0.5 nm or more and 10 nm or less. Preferably, D, the dimension of the particles of the luminescent material or its precursor 50 The value is 0.5 nm or more and 50 nm or less, more preferably 0.5 nm or more and 10 nm or less. Small particles enable small regions within the composite luminescent particles and improve FRET.

[0066] Preferably, at least one of the first luminescent material or the second luminescent material is A3B5O 12 :RE garnet nanoparticles, where A is one or more of yttrium, lutetium, and gadolinium, B is one or more of aluminum, gallium, and scandium, and RE is a rare earth metal. The garnet nanoparticles are a. The glycothermal method, more preferably the method described in Odziomek et al. J. Mater. Chem. C 2017, 5, 12561 b. The precipitation method, more preferably the method described in EP21215315 (incorporated herein by reference) c. The two-step precipitation method, more preferably the method described in EP21218015 (incorporated herein by reference), or d. For example, other methods described in Berends et al. Chem. Rev. 2020, 120, 24, 13461-13479, or other methods described elsewhere in the art can be manufactured by a method known in the art selected from the above.

[0067] Step b) includes mixing the first luminescent material or its precursor, the second luminescent material or its precursor, and the precursor of the oxide material.

[0068] The oxide material is preferably as defined heretofore.

[0069] Preferably, the precursor of the oxide is selected from the group consisting of organic silicates, silicon salts, aluminum salts, magnesium salts, and phosphates.

[0070] More preferably, the precursor of the oxide is selected from silicon salts, aluminum salts, magnesium salts, and phosphates, and the salt is selected from nitride salts or chloride salts. More preferably, the precursor is an ester of orthosilicic acid.

[0071] In one embodiment, the mixing in step b) is simply carried out by adding the precursor of the oxide material to a dispersion of the luminescent material or its precursor. Preferably, the dispersion medium is a water / ethanol mixture. Preferably, the method is by a Stoeber reaction.

[0072] In another embodiment, the mixing is carried out by first producing a water-in-oil microemulsion in which the luminescent material is present in the core of the droplets, and subsequently adding TEOS to the microemulsion. An example of such a method is described in Koole, R.; van Schooneveld, M.M.; Hilhorst, J.; de Mello Donega, C.; ‘t Hart, D.C.; van Blaaderen, A.; Vanmaekelbergh, D.; Meijerink, A. Chem. Mater. 2008, 20, 2503-2512.

[0073] Preferably, step b) includes stirring. Thereby, the luminescent material remains in the dispersion and the distribution of the precursor of the oxide material becomes uniform.

[0074] Preferably, after step b) and before step c), the mixture is further stirred, for example, by ultrasonic treatment. This further ensures a uniform distribution of the precursor of the oxide material and good dispersion of the luminescent material.

[0075] The distance between regions of the luminescent material within the oxide material can be adjusted by varying steps b) and c). This enables adjustment according to the material. Precise adjustment of the inter-particle distance between the first and second luminescent materials in the final composite luminescent particles allows control of the energy transfer efficiency and appropriate control of the emission spectrum.

[0076] Figure 1 shows ways to adjust the distance in various ways: Aspect a shows composite luminescent particles where the regions of the luminescent material are in close contact. Aspect b shows a case where the distance between the regions is long, but still within the same composite luminescent particles. Aspect c shows two particles each containing one luminescent material, allowing for an even longer distance.

[0077] In one aspect, step b) is performed in a single step such that a single mixture is formed. This results in the minimum distance between the regions. Adjusting the distance between the regions is important as it enables not only control of the desired energy transfer (the shorter the distance, the higher the energy transfer efficiency), but also control of the quenching effect (e.g., charge transfer type quenching, less quenching for longer distances).

[0078] In one aspect, step b) is - a step of mixing the first luminescent material or its precursor with the precursor of the oxide material in a first container and mixing the second luminescent material or its precursor with the precursor of the oxide material in a second container, and - a step of mixing the mixtures, is included.

[0079] By mixing the luminescent materials separately with the precursor of the oxide material, the distance between the luminescent materials in the final particles can be adjusted. Thus, in this aspect, the distance between the regions is medium.

[0080] In one aspect, step b) is b1) a step of mixing the first luminescent material or its precursor with the precursor of the oxide material in a first container and mixing the second luminescent material or its precursor with the precursor of the oxide material in a second container, b2) at least partially curing at least one of the obtained mixtures, b3) mixing the at least partially cured mixture, and the like.

[0081] Thereby, the distance between regions becomes longer.

[0082] Step c) includes curing a precursor of the oxide material to obtain cured particles, and the cured particles contain the first luminescent material or its precursor, the second luminescent material or its precursor, and a coating of the oxide material.

[0083] Such curing can be carried out, for example, by a condensation reaction or a hydrolysis reaction. Preferably, the curing is a hydrolysis reaction. More preferably, the curing is carried out by adding an ammonia solution.

[0084] Preferably, the curing is carried out slowly and / or with stirring. Thereby, aggregation of particles is prevented. For example, the ammonia solution may be added dropwise with stirring.

[0085] Preferably, this method further includes drying the cured particles. More preferably, this method includes drying the cured particles at 80°C to 125°C.

[0086] Preferably, this method further includes drying the cured particles at 80°C to 125°C, and pulverizing the dried particles after the curing step c), and / or pulverizing the particles after the heating step d).

[0087] Step d) includes heating the cured particles to at least 200°C. Thereby, crystal defects in the luminescent material can be removed. In the case of a precursor of the luminescent material, this step enables the formation of the luminescent material.

[0088] The coating of the oxide material provides a protective barrier that prevents ion diffusion between the luminescent materials during the annealing process at high temperatures and inactivates surface defects on the region of the luminescent material. These effects lead to an improvement in luminescence intensity.

[0089] Preferably, the heating is performed at least partially in a reducing atmosphere. A reducing atmosphere is an atmosphere in which oxidation is prevented. Preferably, the reducing atmosphere contains carbon monoxide. The reducing atmosphere conditions may be formed by using carbon powder in a double crucible in which a crucible containing the cured particles is placed inside a large crucible containing carbon powder and covered with a lid.

[0090] Preferably, the heating of the cured particles includes heating at at least 500 °C, preferably at least 600 °C, and preferably less than 2000 °C, more preferably less than 1500 °C.

[0091] Preferably, the heating of the cured particles includes heating at a temperature lower than the melting temperature of the oxide coating layer.

[0092] When the first luminescent material and the second luminescent material are Y2O3, Y3Al5O 12 and / or Lu3Al5O 12 the heating temperature is preferably at least 900 °C. Preferably, for such materials, the cured particles are heated for at least 2 hours, more preferably 6 hours.

[0093] When the first luminescent material and / or the second luminescent material includes a phosphate material such as LaPO4, the heating temperature is preferably at most 800 °C. At higher temperatures, the phosphate material may deteriorate. Preferably, for such materials, the cured particles are heated for at least 1 minute, preferably for several hours.

[0094] Furthermore, the present invention a) A first luminescent material which is a fluorescent material doped with a rare earth element, an ion in the s2 configuration, or a transition metal, or a precursor of the first luminescent material; a second luminescent material which is a fluorescent material doped with a rare earth element, an ion in the s2 configuration, or a transition metal, or a precursor of the second luminescent material are prepared; and a precursor of an oxide material is further prepared, wherein the melting point of the oxide material is at least 700 °C, and the oxide material is selected from the group consisting of silicon oxide, aluminum oxide, phosphate, or magnesium oxide. b) Mixing either one of the first luminescent material or its precursor and the second luminescent material or its precursor with the precursor of the oxide material. c) Curing the precursor of the oxide material to obtain cured particles, the cured particles containing either one of the first luminescent material or its precursor and the second luminescent material or its precursor, as well as a coating of the oxide material. d) Mixing the cured particles with the remaining luminescent material or its precursor, wherein the remaining luminescent material or its precursor is optionally coated with an oxide material having a melting point of at least 700 °C, and e) Heating the mixture to at least 200 °C. relates to a method for producing a luminescent composition comprising The first luminescent material can emit light in a first wavelength range, the second luminescent material can absorb light in a second wavelength range, and has an emission spectrum that at least partially overlaps with one or more of the excitation bands of the first luminescent material.

[0095] This method enables the production of the luminescent composition of the present invention.

[0096] This method differs from the method for producing composite luminescent particles in that the first luminescent material and the second luminescent material are not contained in a single composite luminescent particle.

[0097] Step a) of the method of the present invention is the same, and thus the same preferred embodiments as described above apply.

[0098] Step b) includes mixing either the first luminescent material or its precursor and the second luminescent material or its precursor with the precursor of the oxide material.

[0099] The oxide material is preferably as defined previously, and the precursor is as defined previously.

[0100] In one embodiment, the mixing in step b) is simply performed by adding the precursor of the oxide material to a dispersion of the second luminescent material or its precursor. Preferably, the dispersion medium is a water / ethanol mixture. Preferably, the method is by a Stover reaction.

[0101] In another embodiment, the mixing is performed by first producing a water-in-oil microemulsion in which the second luminescent material is present in the core of the droplets, and subsequently adding TEOS to the microemulsion. An example of such a method is described in Koole, R.; van Schooneveld, M.M.; Hilhorst, J.; de Mello Donega, C.; ‘t Hart, D.C.; van Blaaderen, A.; Vanmaekelbergh, D.; Meijerink, A. Chem. Mater. 2008, 20, 2503-2512.

[0102] Preferably, step b) includes stirring. Thereby, the luminescent material remains in the dispersion, and the distribution of the precursor of the oxide material becomes uniform.

[0103] Preferably, after step b) and before step c), the mixture is further stirred, for example, by ultrasonic treatment. This further ensures a uniform distribution of the precursor of the oxide material and a good dispersion of the luminescent material.

[0104] Step c) includes curing the precursor of the oxide material. Preferably, the curing is a hydrolysis reaction. More preferably, the curing is performed by adding an ammonia solution.

[0105] Preferably, the curing is carried out slowly and / or with stirring. This prevents aggregation of the particles. For example, an ammonia solution may be dropped while stirring.

[0106] Preferably, this method further includes drying the cured particles. More preferably, this method includes drying the cured particles at 80°C to 125°C.

[0107] Preferably, this method further includes drying the cured particles at 80°C to 125°C, and pulverizing the dried particles after the curing step c) and / or pulverizing the particles after the heating step e).

[0108] The mixing step d) can be carried out by methods known in the art, such as dry mixing, or drying after dispersion in a liquid.

[0109] The heating step e) is preferably carried out as described in the heating step d).

[0110] Preferably, the heating of the mixture includes mixing the mixture with a salt before heating, as described in International Publication No. WO 2021 / 043762. This can protect the first luminescent material that may not be coated.

[0111] In one embodiment, the remaining luminescent material or its precursor is coated with an oxide material having a melting point of at least 700°C. Preferably, the oxide material is as defined previously. Thereby, the embodiment of Figure 1c is obtained.

[0112] The separation of the luminescent particles or regions can be further adjusted by changing the ratio between the amount of the luminescent particles or their precursors and the amount of the precursor of the oxide coating material.

[0113] Furthermore, the present invention relates to a light-emitting device comprising the composite light-emitting particles of the present invention or the light-emitting composition of the present invention. Preferably, the light-emitting device further comprises an excitation source for the light-emitting material, for example, for a second light-emitting material. Preferably, the excitation source is a UV-A, violet or blue light-emitting material that emits light in the range of 315 to 400 nm (UV-A), 400 to 440 nm (violet) or 440 to 480 nm (blue), more preferably 430 to 465 nm, to the light-emitting material.

[0114] The light-emitting device may be composed of a blue light-emitting LED in which the light-emitting nanoparticles or the light-emitting composition of the present invention is deposited on an LED chip. The nanoparticles of the present invention may be combined with a polymer or a silicone slurry that is deposited on a blue LED chip and then cured.

[0115] Furthermore, the present invention relates to a lighting system comprising the light-emitting device of the present invention. Preferably, the lighting system is selected from the group consisting of a lamp or luminaire, an office lighting system, a household system, a store lighting system, a residential lighting system, an accent lighting system, a spot lighting system, a theater lighting system, a system for optical fibers, a projection system, a self-luminous display system, a pixel display system, a segment display system, a warning display system, a medical lighting system, a sign display system, a decorative lighting system, a portable system, an automotive system, and a greenhouse lighting system.

[0116] Furthermore, the present invention relates to the use of the light-emitting composition or the light-emitting material of the present invention containing the light-emitting nanoparticles of the present invention as a tagant. A tagant is a marker added to a material to enable various tests. The overall excitation / emission spectrum of the composite light-emitting particles and / or the light-emitting composition of the present invention may have unique characteristics compared to conventional methods, and thus may be useful as an anti-counterfeiting tagant. For example, U.S. Patent No. 7,667,828 discloses a tagging system containing different types of tagants.

[0117] The present invention is further defined by the following clauses. 1. A composite light-emitting particle containing: (i) a first light-emitting material which is a fluorescent material doped with a rare earth element, an ion having an s2 configuration, or a transition metal; (ii) a second light-emitting material which is a fluorescent material doped with a rare earth element, an ion having an s2 configuration, or a transition metal; and (iii) further containing a coating of an oxide material having a melting point of 700 °C or higher, wherein the oxide material is selected from the group consisting of silicon oxide, aluminum oxide, phosphate, or magnesium oxide. The D of the composite light-emitting particles measured by a transmission electron microscope (TEM) 50 value is from 1 nm to 100 μm, the composite light-emitting particles. 2. The first light-emitting material can emit light in a first wavelength range, the second light-emitting material can absorb light in a second wavelength range, and has an emission spectrum that at least partially overlaps with one or more of the excitation bands of the first light-emitting material. Preferably, the first light-emitting material and the second light-emitting material are arranged relative to each other so as to enable non-radiative energy transfer from the second light-emitting material to the first light-emitting material, the composite light-emitting particles according to item 1. 3. The first light-emitting material and the second light-emitting material each form a region inside the oxide material, the region has a bulk, and the D of the minimum dimension of the region measured by a transmission electron microscope (TEM) 50 value is from 0.5 nm to 100 nm, more preferably from 0.5 nm to 50 nm, and most preferably from 0.5 nm to 10 nm, the composite light-emitting particles according to item 2. 4. The D of the composite light-emitting particles measured by a transmission electron microscope (TEM) 50 value is from 1 nm to 50 μm, more preferably from 20 nm to 10 μm, and most preferably from 50 nm to 10 μm, the composite light-emitting particles according to any one of the preceding items. 5. A light-emitting composition containing: (i) a first light-emitting material which is a fluorescent material doped with a rare earth element or a transition metal, an ion having an s2 configuration; (ii) a second light-emitting material which is a fluorescent material doped with a rare earth element or a transition metal, an ion having an s2 configuration. At least one of the first luminescent material or the second luminescent material is contained in particles coated with an oxide material having a melting point of 700 °C or higher, and the oxide material is selected from the group consisting of silicon oxide, aluminum oxide, phosphate, or magnesium oxide. The D 50 value of the coated particles measured by a transmission electron microscope (TEM) is 1 nm or more and 100 μm or less, Preferably, the first luminescent material can emit light in a first wavelength range, the second luminescent material can absorb light in a second wavelength range, and has an emission spectrum that at least partially overlaps with one or more of the excitation bands of the first luminescent material. More preferably, the first luminescent material and the second luminescent material are arranged relative to each other to enable non-radiative energy transfer from the second luminescent material to the first luminescent material, a luminescent composition. 6. The first luminescent material and / or the second luminescent material is selected from the group consisting of oxides, fluorides, nitrides, borates, garnets, molybdates, phosphates, vanadates, chlorides, sulfides, selenides, silicates, aluminates, oxyfluorides, oxychlorides, oxynitrides, oxysulfides, oxy selenides, fluorochlorides, fluorosilicates, and fluorobromides, or combinations thereof, preferably selected from the group consisting of oxides, phosphates, vanadates, or combinations thereof. More preferably, Y3Al5O 12 、Lu3Al5O 12 Selected from the group consisting of Y2O3, YVPO4, YVO4, or LaPO4, or combinations thereof, the composite luminescent particles according to any one of items 1 to 4, or the luminescent composition according to item 5. 7. The oxide material is selected from the group consisting of silica, alumina, magnesium oxide, and phosphate, the composite luminescent particles according to any one of items 1 to 4 or 6, or the luminescent composition according to items 5 or 6. 8. a) (i) A first luminescent material that is a fluorescent material doped with a rare earth element, an s2 configuration ion, or a transition metal, or a precursor of the first luminescent material; (ii) preparing a second luminescent material that is a fluorescent material doped with a rare earth element, an s2 configuration ion, or a transition metal, or a precursor of the second luminescent material; (iii) further preparing a precursor of an oxide material, wherein the melting point of the oxide material is at least 700 °C, and the oxide material is selected from the group consisting of silicon oxide, aluminum oxide, phosphate, or magnesium oxide, b) Mixing the first luminescent material or its precursor, the second luminescent material or its precursor, and the precursor of the oxide material, c) Curing the precursor of the oxide material to obtain cured particles, the cured particles containing the first luminescent material or its precursor, the second luminescent material or its precursor, and a coating of the oxide material, and d) Heating the cured particles to at least 200 °C, A method for manufacturing composite luminescent particles including the above steps. 9. The method according to item 8, wherein the first luminescent material can emit light in a first wavelength range, the second luminescent material can absorb light in a second wavelength range, and has an emission spectrum that at least partially overlaps with one or more of the excitation bands of the first luminescent material. 10. The method according to item 8 or 9, wherein step b) of the method is carried out in a single step such that a single mixture is formed. 11. Step b) of the method is b1) In a first container, mixing the first luminescent material or its precursor with the precursor of the oxide material, and in a second container, mixing the second luminescent material or its precursor with the precursor of the oxide material, b2) Optionally, at least partially curing at least one of the obtained mixtures, b3) Optionally, mixing the at least partially cured mixtures, The method according to item 8 or 9 including the above steps.

[0118] 12. a) (i) A first luminescent material which is a fluorescent material doped with a rare earth element, an ion having an s2 configuration, or a transition metal, or a precursor of the first luminescent material; (ii) preparing a second luminescent material which is a fluorescent material doped with a rare earth element, an ion having an s2 configuration, or a transition metal, or a precursor of the second luminescent material; (iii) further preparing a precursor of an oxide material, wherein the melting point of the oxide material is at least 700 ° C, and the oxide material is selected from the group consisting of silicon oxide, aluminum oxide, phosphate, or magnesium oxide, b) Mixing either the first luminescent material or its precursor and either the second luminescent material or its precursor with the precursor of the oxide material, c) Curing the precursor of the oxide material to obtain cured particles, the cured particles containing either the first luminescent material or its precursor and either the second luminescent material or its precursor, as well as a coating of the oxide material, d) Mixing the cured particles with the remaining luminescent material or its precursor, wherein the remaining luminescent material or its precursor is optionally coated with an oxide material having a melting point of at least 700 ° C, and e) Heating the mixture to at least 200 ° C, A method for producing a luminescent composition, comprising: The first luminescent material can emit light in a first wavelength range, the second luminescent material can absorb light in a second wavelength range, and the method has an emission spectrum that at least partially overlaps with one or more of the excitation bands of the first luminescent material. 13. The first luminescent material or its precursor, and / or the second luminescent material or its precursor are provided as particles, and the D 50 value of the minimum dimension of the particles measured by a transmission electron microscope (TEM) is 0.5 nm or more and 50 nm or less, preferably 0.5 nm or more and 10 nm or less. The method according to any one of items 8 to 12. 14. The precursor of the oxide material is selected from the group consisting of organic silicate esters, silicon salts, aluminum salts, phosphate salts, and magnesium salts. Preferably, the salt is selected from nitride salts or chloride salts, and / or the precursor is an ester of orthosilicic acid. The method according to any one of items 8 to 13. 15. Step c) includes a hydrolysis reaction. Preferably, the oxide material is silica, and step c) includes adding ammonia to cure the precursor of the oxide material. The method according to any one of items 8 to 14. 16. The method further includes a step of drying and pulverizing the particles after the curing step c), and / or a step of pulverizing the particles after the heating step d) or the heating step e). The method according to any one of items 8 to 15. 17. The heating includes heating at at least 500 °C, preferably at least 600 °C, preferably less than 2000 °C, more preferably less than 1500 °C. The method according to any one of items 8 to 16. 18. The heating includes heating for at least 1 minute, preferably for at least 5 minutes. The method according to any one of items 8 to 17. 19. The heating is carried out at least partially in a reducing atmosphere. The method according to any one of items 8 to 18. 20. A light-emitting device including the composite light-emitting particles according to any one of items 1 to 6 or the light-emitting composition according to item 7, and a purple and / or blue light-emitting semiconductor material. 21. A system including the composite light-emitting particles according to any one of items 1 to 6, the light-emitting composition according to item 7, and / or the light-emitting device according to item 20, wherein the system is a. An office lighting system b. A household system c. A store lighting system d. A residential lighting system e. An accent lighting system c. A spot lighting system g. A theater lighting system h. A system for optical fibers i. A projection system j. Self-luminous display system k. Pixel display system l. Segment display system m. Warning display system n. Medical lighting system o. Sign display system p. Decorative lighting system q. Portable system r. Automotive system s. Greenhouse lighting system t. Display device backlight u. Light-emitting display v. Micro LED A system that is one or more of the above. 22. Use of the composite luminescent particles described in any one of Items 1 to 6 or the luminescent composition described in Item 7 as a tagant in applications such as anti-counterfeiting.

Examples

[0119] In the examples, the following particles were used: LaPO4:50%Tb nanoparticles with ethylene glycol ligands were obtained according to the procedure of European Patent Application Publication No. 3623449. The shape of the particles was spherical, and the D value of the minimum dimension was 10 nm. 50 The value was 10 nm. Y2O3:15%Eu nanoparticles were obtained according to the procedure of European Patent Application Publication No. 3922698. The shape of the particles was platelet-like, with a width of less than 1000 nm and a thickness of less than 10 nm. Y3Al5O 12 Nanoparticles were obtained according to the procedure of European Patent Application No. 22152028 under examination. The shape of the particles was spherical, and the D value of the minimum dimension was 10 nm. 50 The value was 10 nm.

[0120] Comparative Example A: A luminescent composition in which LaPO of 1:1 4 : 50% Tb and Y 2 O 3 : 15% Eu are sufficiently mixed 100 mg of LaPO4:50%Tb nanoparticles and 100 mg of Y2O3:15%Eu nanoparticles were weighed into a glass vial and dispersed using 5 mL of water. The vial was then sonicated for 90 minutes. The water was completely evaporated at 105 °C with gentle stirring. The powder was then ground using an agate mortar and pestle and analyzed.

[0121] The emission spectrum showed Eu 3+ sensitized by Tb (IFRET) upon excitation 3+ and emitted light (Figure 1, dotted line).

[0122] Comparative Example B: A luminescent composition in which LaPO of 3:1 4 : 50% Tb and Y 2 O 3 : 15% Eu are sufficiently mixed 300 mg of LaPO4:50%Tb nanoparticles and 100 mg of Y2O3:15%Eu nanoparticles were weighed into a glass vial and dispersed using 5 mL of water. The vial was then sonicated for 90 minutes. The water was completely evaporated at 105 °C with gentle stirring. The powder was then ground using an agate mortar and pestle and analyzed.

[0123] The emission spectrum showed improved Eu 3+ emission compared to Example A (Figure 2, dashed line).

[0124] Comparative Example C: Annealing of the luminescent composition of Example A Samples were prepared according to Comparative Example A. The samples were placed in an alumina crucible and transferred to an oven. Annealing was carried out in an air atmosphere at 600 °C for 2 hours and cooled to room temperature.

[0125] The annealed samples changed from the white powder before annealing to brown after the annealing process. The brown coloration implies that ions diffused during annealing, resulting in the formation of trace amounts of another compound such as Y2O3:Tb with Tb 4+ impurity ions. The photoluminescence properties also significantly deteriorated.

[0126] In further experiments, various annealing temperatures (500, 600, 700, 800, 1000, 1200 °C) were investigated in air and in a reducing atmosphere. The crucible containing the sample was placed in a larger crucible containing carbon powder, and reduction atmosphere annealing was carried out using the carbon powder in a double crucible covered with a lid. In all cases, the annealed samples did not show an improvement in photoluminescence properties compared to Comparative Example A.

[0127] Comparative Example D: Annealing of a luminescent composition containing Y 3 Al 5 O 12 : Ce 3+ and Y 2 O 3 : Eu without a silica matrix 3+ Comparative Example E: Annealing of a luminescent composition containing Y 100 mg of YAG:3%Ce 3+ nanoparticles and 100 mg of Y2O3:Eu 3+ nanoparticles were weighed and dispersed in 5 mL of water. The vial was then sonicated for 90 minutes. The liquid was completely evaporated at 105 °C while stirring gently. The dried powder was then ground using an agate mortar and pestle. The powder was transferred to an alumina crucible and then placed in an oven. The crucible containing the sample was placed in a larger crucible containing carbon powder, and the sample was annealed in a reducing atmosphere at 1300 °C for 2 hours using a double crucible covered with a lid.

[0128] The annealed powder was bright yellow, but did not emit light under Ce 3+ excitation at 450 nm (dotted line in Figure 9). The absence of Ce 3+ luminescence implies metal-to-metal charge transfer quenching of Ce 3+ . This suggests that Ce 3+ and Eu 3+ ions are too close to each other.

[0129] : Ce 3 Al 5 O 12 without a silica matrix, Tb3+ and Y 3+ : Eu, Tb 3 Al 5 O 12 Comparative Example F: Annealing of a luminescent composition containing Y 3+ : Ce 3+ without a silica matrix, Tb 50 mg of YAG:0.1%Ce 3+ , 50%Tb 3+ nanoparticles and 100 mg of Y3Al5O 12 :20%Eu 3+ , 30%Tb 3+ nanoparticles were weighed and dispersed in 5 mL of water. Then, the vial was sonicated for 90 minutes. The liquid was completely evaporated at 105 °C while stirring gently. Then, the dried powder was ground using an agate mortar and pestle. The powder was transferred to an alumina crucible and then placed in an oven. The crucible containing the sample was placed in a larger crucible containing carbon powder and covered with a lid. Using the carbon powder in a double crucible, the sample was annealed in a reducing atmosphere at 1025 °C for 6 hours.

[0130] The annealed powder was pale yellow, but showed weak luminescence upon Ce 3+ excitation at 440 nm (dotted line in Figure 10). The weak Ce 3+ luminescence implies quenching of Ce 3+ , which is most likely caused by metal-to-metal charge transfer interactions. This suggests that Ce 3+ and Eu 3+ ions are in close proximity to each other.

[0131] Luminescent Particles Containing One Type of Luminescent Material Example 1: Annealing of Y 2 O 3 : 15% Eu nanoparticles encapsulated in a silica matrix 60 mg of Y2O3:15%Eu nanoparticles were weighed into a glass vial. 1 mL of water and 1 mL of ethanol were added to the vial and shaken well. Then, 50 μL of TEOS was added dropwise to the vial while gently stirring. Next, the vial was sonicated for 5 minutes, and then 1 mL of ammonia solution (32% aqueous ammonia) was slowly added dropwise to the vial while stirring continuously. The vial was stirred for 30 minutes. After stirring, it was dried at 105 °C while gently stirring to completely evaporate the solvent. The obtained powder was ground using a mortar and pestle and transferred to an alumina crucible. Then, following the double crucible of carbon described above, the crucible was placed in an oven and annealed at 1000 °C for 8 hours in a reducing atmosphere and then cooled to room temperature. Again, the powder was ground using a mortar and pestle and analyzed.

[0132] The annealed sample did not change in color from white and showed stronger photoluminescence intensity compared to the Y2O3:15%Eu nanoparticles before encapsulation or annealing. This can be confirmed in Figure 3, where the particles of Example 1 are shown by a solid line and the untreated Y2O3:15%Eu nanoparticles are shown by a dotted line.

[0133] Example 2: Annealing of YAG:1% Ce nanoparticles encapsulated in a silica matrix 30 mg of Y3Al5O 12 :1%Ce nanoparticles were weighed into a glass vial. 1 mL of water and 1 mL of ethanol were added to the vial and shaken well. Then, 50 μL of TEOS was added dropwise to the vial while gently stirring. Next, the vial was sonicated for 5 minutes, and then 1 mL of ammonia solution (32% aqueous ammonia) was slowly added dropwise to the vial while stirring continuously. The vial was stirred for 30 minutes. After stirring, it was dried at 105 °C while gently stirring to completely evaporate the solvent. The obtained powder was ground using an agate mortar and pestle and transferred to an alumina crucible. Then, following the double crucible of carbon described above, the crucible was placed in an oven and annealed at 1000 °C for 8 hours in a reducing atmosphere and then cooled to room temperature. Again, the powder was ground using an agate mortar and pestle and analyzed.

[0134] The annealed sample showed a pale yellow color and exhibited bright photoluminescence (the emission spectrum is shown in Figure 4).

[0135] Luminescent Particles Containing Multiple Luminescent Materials Example 3: LaPO obtained from a single dispersion 4 : Tb and Y 2 O 3 : Luminescent particles containing Eu 150 mg of LaPO4:50%Tb and 50 mg of Y2O3:15%Eu nanoparticles were weighed into a glass vial and dispersed in 5 mL of water. The vial was then sonicated for 90 minutes. The water was evaporated until the sample volume became 3 mL. Then, 3 mL of ethanol was added to the vial and mixed well. 150 μL of TEOS was pipetted and dropped into the vial while stirring gently. After the addition was complete, the vial was sonicated for 5 minutes.

[0136] Next, while stirring continuously, 3 mL of ammonia solution (32 wt% aqueous ammonia) was slowly dropped into the vial. The sample was stirred for an additional 30 minutes and then dried at 105 °C while stirring gently. The obtained powder was ground using an agate mortar and pestle and transferred to an alumina crucible. The crucible was placed in an oven. Using the double crucible of carbon described above, the sample was annealed in a reducing atmosphere at 700 °C for 10 minutes and then cooled to room temperature. Again, the powder was ground using an agate mortar and pestle and analyzed.

[0137] The annealed sample did not change from white. The sample exhibited photoluminescence with improved intensity and energy transfer efficiency. In Figure 5, the sample of Example 3 is shown by a solid line and the sample of Comparative Example B is shown by a dotted line. The photoluminescence intensity was improved by about 5 times compared to Comparative Example B, and the photoluminescence quantum efficiency was improved by 3 times compared to Comparative Example B.

[0138] Example 4: LaPO obtained from two dispersions cured as a single dispersion 4 : Tb and Y 2 O 3 : Luminescent particles containing Eu 150 mg of LaPO4:50%Tb nanoparticles were weighed into a glass vial, and 50 mg of Y2O3:15%Eu nanoparticles were weighed into another glass vial. 1.5 mL of water and 1.5 mL of ethanol were added to each vial. After shaking the dispersion, 75 μL of TEOS was added dropwise to each vial while gently stirring. Then, the vials were sonicated for 5 minutes.

[0139] The dispersions in the vials were mixed and sonicated for 90 minutes. Then, while stirring continuously, 3 mL of ammonia solution (32% aqueous ammonia) was slowly added dropwise to the vials. Stirring was continued for an additional 30 minutes. It was dried at 105 °C while gently stirring. The obtained powder was ground using an agate mortar and pestle, transferred to an alumina crucible, and annealed in a reducing atmosphere at 700 °C for 10 minutes according to the double crucible of carbon described above. The sample was cooled to room temperature. Then, the powder was ground again using an agate mortar and pestle and analyzed.

[0140] The annealed sample did not change from white and showed photoluminescence with improved intensity and moderate energy transfer efficiency compared to Comparative Example A, as shown in Figure 6. In Figure 6, Example 4 is shown by a solid line and Comparative Example B is shown by a dotted line.

[0141] Example 5: LaPO obtained from two dispersions cured separately 4 : Tb and Y 2 O 3 : Luminescent particles containing Eu 150 mg of LaPO4:50%Tb nanoparticles were weighed into a glass vial, and 50 mg of Y2O3:15%Eu nanoparticles were weighed into another glass vial. 1.5 mL of water and 1.5 mL of ethanol were added to each vial, and the vials were shaken well. Then, 75 μL of TEOS was added dropwise to each vial while gently stirring. The vials were sonicated for 5 minutes, and then 1.5 ml of ammonia solution (32% aqueous ammonia) was slowly added dropwise to each vial while stirring continuously. Each vial was stirred for 30 minutes.

[0142] After stirring, the dispersions in each vial were mixed and sonicated for 90 minutes. Then, while gently stirring, it was dried at 105 °C to completely evaporate the liquid. The obtained powder was ground using an agate mortar and pestle and transferred to an alumina crucible. Then, using the double crucible of carbon described above, the crucible was placed in an oven and annealed in a reducing atmosphere at 700 °C for 10 minutes and cooled to room temperature. Again, the powder was ground using an agate mortar and pestle and analyzed.

[0143] The annealed sample did not change from white and showed photoluminescence with higher intensity and relatively low energy transfer efficiency compared to Comparative Example B. In Figure 7, Comparative Example B is shown as a dotted line and Example 5 is shown as a solid line.

[0144] Example 6: LaPO obtained from two dispersions cured as a single dispersion with a longer stirring time 4 : Tb and Y 2 O 3 : Luminescent particles containing Eu 150 mg of LaPO4:50% Tb nanoparticles were weighed into a glass vial, and 50 mg of Y2O3:15% Eu nanoparticles were weighed into another glass vial. To each vial, 1.5 mL of water and 1.5 mL of ethanol were added. The dispersion was shaken well and then 75 μL of TEOS was added dropwise to each vial while gently stirring. Then, the vial was sonicated for 5 minutes and stirred for 5 hours.

[0145] After stirring, the dispersions in each vial were mixed and sonicated. It was dried at 105 °C while gently stirring. The obtained powder was ground using an agate mortar and pestle, transferred to an alumina crucible, and annealed in a reducing atmosphere at 700 °C for 10 minutes according to the double crucible of carbon described above and cooled to room temperature. Again, the powder was ground using an agate mortar and pestle and analyzed.

[0146] The annealed sample did not change from white and showed improved photoluminescence intensity. In Fig. 8, the sample of Example 6 is shown by a solid line and the sample of Example 3 is shown by a dotted line. Compared with Example 4, the energy transfer efficiency was improved. Compared with Comparative Example B, the photoluminescence intensity was improved by about 10 times, and the photoluminescence quantum efficiency was improved by 4 times compared with Comparative Example B.

[0147] Example 7: YAG:Ce, Tb and Y obtained from two dispersions cured separately 2 O 3 : Luminescent particles containing Eu 30 mg of YAG: 1% Ce, 30% Tb nanoparticles were weighed into a glass vial. 60 mg of Y2O3: 15% Eu nanoparticles were weighed into another glass vial. 1 mL of water and 1 mL of ethanol were added to each vial. The dispersion was shaken well and then 50 μL of TEOS was added dropwise to each vial while gently stirring. The vials were sonicated for 5 minutes. Then, 1 mL of ammonia solution (32% aqueous ammonia) was slowly added dropwise to each vial while stirring continuously. Each vial was stirred for 30 minutes.

[0148] After stirring, the dispersions in each vial were mixed and sonicated for 90 minutes. They were dried at 105 °C while gently stirring to completely evaporate the solvent. The obtained powder was ground using a mortar and pestle, transferred to an alumina crucible, and annealed at 1000 °C for 8 hours in a reducing atmosphere according to the double crucible of carbon described above, and then cooled to room temperature. Again, the powder was ground using a mortar and pestle and analyzed.

[0149] The annealed sample showed light yellow and YAG:Ce 3+ showed bright photoluminescence upon excitation. Fig. 9 shows the emission spectra of Example 7 (solid line) and Comparative Example D (dotted line) when excited at 440 nm. Eu 3+ luminescence can be observed.

[0150] Example 8: YAG:Ce, Tb and Y obtained from two dispersions cured separately with a longer stirring time 2 O 3 : Luminescent particles containing Eu 30 mg of YAG:1%Ce, 30%Tb nanoparticles were weighed into a glass vial. 60 mg of Y2O3:15%Eu nanoparticles were weighed into another glass vial. 1 mL of water and 1 mL of ethanol were added to each vial. Then, the dispersion was shaken well and 50 μL of TEOS was added dropwise to each vial while gently stirring.

[0151] Next, the vials were sonicated for 5 minutes and stirred for 5 hours. After stirring, the dispersions in the vials were mixed, sonicated for 90 minutes, and then dried at 105 °C while gently stirring to completely evaporate the solvent. The obtained powder was ground using a mortar and pestle and transferred to an alumina crucible. Using the double crucible of carbon described above, the sample was annealed at 1000 °C for 8 hours in a reducing atmosphere and cooled to room temperature. Again, the powder was ground using a mortar and pestle and analyzed.

[0152] The annealed sample showed a pale yellow color. Upon excitation at 440 nm, the luminescence intensity decreased compared to Example 7. 3+

[0153] Example 9: Luminescent particles containing YAG:Ce, Tb and YAG:Eu, Tb obtained from two dispersions cured separately 30 mg of YAG:0.1%Ce, 50%Tb nanoparticles were weighed into a glass vial. 60 mg of YAG:20%Eu, 30%Tb nanoparticles were weighed into another glass vial. 1 mL of water and 1 mL of ethanol were added to each vial. The dispersion was shaken well and 50 μL of TEOS was added dropwise to each vial while gently stirring. Then, the vials were sonicated for 5 minutes and stirred for 30 minutes. Then, 1 mL of ammonia solution (32% aqueous ammonia) was slowly added dropwise to each vial while stirring continuously. Each vial was stirred for 30 minutes.

[0154] ​After stirring, the dispersion liquids in each vial were mixed and sonicated for 90 minutes. While gently stirring, it was dried at 105 °C to completely evaporate the solvent. The obtained powder was pulverized using a mortar and pestle, transferred to an alumina crucible, and annealed in a reducing atmosphere at 1025 °C for 6 hours according to the double crucible of carbon described above, and then cooled to room temperature. Again, the powder was pulverized using a mortar and pestle and analyzed.

[0155] The annealed sample showed a pale yellow color, YAG:Ce 3+ showed bright photoluminescence upon excitation. Figure 10 shows the emission spectra of Example 9 (solid line), Example 10 (dashed line), and Comparative Example E (dotted line) when excited at 440 nm. Ce 3+ emission lines of Eu by iFRET could be observed upon excitation at 3+ 440 nm.

[0156] Example 10: Luminescent particles containing YAG:Ce, Tb and YAG:Eu, Tb obtained from two dispersions with a lower silica content cured separately 30 mg of YAG:0.1%Ce, 50%Tb nanoparticles were weighed into a glass vial. 60 mg of YAG:20%Eu, 30%Tb nanoparticles were weighed into another glass vial. 0.25 mL of water and 0.25 mL of ethanol were added to each vial. The dispersion liquid was shaken well, and then while gently stirring, 12.5 μL of TEOS was dropped into each vial. The vial was sonicated for 5 minutes and stirred for 30 minutes. Then, while continuously stirring, 0.25 mL of ammonia solution (32% aqueous ammonia) was slowly dropped into each vial. Each vial was stirred for 30 minutes.

[0157] After stirring, the dispersion liquids in each vial were mixed and sonicated for 90 minutes. While gently stirring, it was dried at 105 °C to completely evaporate the solvent. The obtained powder was pulverized using a mortar and pestle, transferred to an alumina crucible, and annealed in a reducing atmosphere at 1025 °C for 6 hours according to the double crucible of carbon described above, and then cooled to room temperature. Again, the powder was pulverized using a mortar and pestle and analyzed.

[0158] The annealed sample showed a pale yellow color, YAG:Ce 3+Exhibited bright photoluminescence upon excitation. Figure 10 shows the emission spectra of Example 10 (dashed line), Example 9 (solid line), and Comparative Example E (dotted line) when excited at 440 nm. Ce 3+ Upon excitation, Eu by iFRET 3+ Emission of the line can be observed. Ce 3+ The emission intensity of the emission has increased compared to Example 9, probably due to a decrease in dilution caused by a lower silica content. Eu by iFRET 3+ Emission of the line is also improved, suggesting that energy transfer has been improved for a lower silica content by the thin silica shell separating the donor and the emissive nanoparticles.

[0159] Example 11: Luminescent particles containing YAG:Ce, Tb and YAG:Eu, Tb obtained from two dispersions with a medium silica content, higher Tb and Ce doping and lower Eu doping, cured separately, with a mixing ratio of 1:1 30 mg of YAG:0.5%Ce, 75%Tb nanoparticles were weighed into a glass vial. 30 mg of YAG:5%Eu, 75%Tb nanoparticles were weighed into another glass vial. 1 mL of water and 1 mL of ethanol were added to each vial. Then, while stirring continuously, 1 mL of ammonia solution (32% aqueous ammonia) was added dropwise to each vial. Each vial was stirred for 30 minutes. The dispersion was shaken well and then 27 μL of TEOS was added dropwise to each vial while stirring gently. Then, the vials were sonicated for 5 minutes and stirred for 1 hour. After stirring, the dispersions in each vial were mixed, stirred for 24 hours, and sonicated for 90 minutes. It was dried at 105 °C while stirring gently to completely evaporate the solvent. The obtained powder was ground using a mortar and pestle, transferred to an alumina crucible, annealed at 1025 °C for 4 hours, and then cooled to room temperature. Again, the powder was ground using a mortar and pestle and analyzed.

[0160] The annealed sample showed a transparent yellow color and exhibited bright photoluminescence upon excitation with YAG:Ce 3+ Exhibited bright photoluminescence upon excitation. Figure 11 shows the emission spectrum when excited at 440 nm. Ce 3+ Upon excitation, Eu by iFRET 3+ Emission of the line can be observed.

[0161] Example 12: Luminescent particles containing YAG:Ce, Tb and YAG:Eu, Tb, obtained from two dispersions with a mixing ratio of 1:1, having a medium silica content, higher Tb and Ce doping and lower Eu doping, and being partially cured 30 mg of YAG: 0.5% Ce, 75% Tb nanoparticles were weighed into a glass vial. 30 mg of YAG: 5% Eu, 75% Tb nanoparticles were weighed into another glass vial. 1 mL of water and 1 mL of ethanol were added to each vial. The dispersion was shaken well and then 27 μL of TEOS was added dropwise to each vial while gently stirring. After stirring for 30 minutes, 0.15 mL of ammonia solution (0.3% aqueous ammonia) was added dropwise. The vial was stirred for 24 hours.

[0162] After stirring, the dispersions in each vial were mixed and sonicated for 90 minutes. Then, 0.5 mL of ammonia solution (3% aqueous ammonia) was added dropwise while stirring continuously, and stirring was continued for another 30 minutes.

[0163] It was dried at 105 °C while gently stirring to completely evaporate the solvent. The obtained powder was ground using a mortar and pestle, transferred to an alumina crucible, annealed at 1025 °C for 4 hours, and cooled to room temperature. Again, the powder was ground using a mortar and pestle and analyzed.

[0164] The annealed sample showed a transparent yellow color and bright photoluminescence upon YAG:Ce 3+ excitation. Figure 12 shows the emission spectrum when excited at 440 nm. Eu 3+ emission by iFRET can be observed upon excitation at 440 nm. The Eu emission is improved compared to Example 11 due to partial curing of the silica shell before mixing. 3+ lines

[0165] Example 13: Luminescent particles containing TAG:Ce and TAG:Eu, obtained from two dispersions with a mixing ratio of 1:1, having a medium silica content and being partially cured 30 mg of YAG:0.5%Ce, 99.5%Tb (TAG:0.5%Ce) nanoparticles were weighed into a glass vial. 30 mg of YAG:5%Eu, 95%Tb (TAG:5%Eu) nanoparticles were weighed into another glass vial. 1 mL of water and 1 mL of ethanol were added to each vial. The dispersion was shaken well and then 18 μL of TEOS was added dropwise to each vial while gently stirring. After stirring for 30 minutes, 0.15 ml of ammonia solution (0.3% aqueous ammonia) was added dropwise. The vial was stirred for 24 hours.

[0166] After stirring, the dispersions in each vial were mixed and sonicated for 90 minutes. Then, while stirring continuously, 0.5 mL of ammonia solution (3% aqueous ammonia) was added dropwise and stirring was continued for another 30 minutes.

[0167] The mixture was dried at 105 °C while gently stirring to completely evaporate the solvent. The resulting powder was ground using a mortar and pestle, transferred to an alumina crucible, annealed at 1025 °C for 4 hours, and then cooled to room temperature. Again, the powder was ground using a mortar and pestle and analyzed.

[0168] The annealed sample showed a transparent yellow color and bright photoluminescence upon excitation by YAG:Ce 3+ Figure 13 shows the emission spectrum when excited at 440 nm. Upon excitation at 440 nm, the emission of the Eu 3+ line can be observed by iFRET. Due to the higher Tb content and lower silica content, the Eu emission is improved compared to Examples 11 and 12, and further improved compared to Example 11 due to the partial curing of the silica shell before mixing. 3+ line can be observed by iFRET. Due to the higher Tb content and lower silica content, the Eu emission is improved compared to Examples 11 and 12, and further improved compared to Example 11 due to the partial curing of the silica shell before mixing.

Claims

1. (i) a first luminescent material which is a fluorescent material doped with a rare earth element, an s2 configuration ion, or a transition metal; (ii) a second luminescent material which is a fluorescent material doped with a rare earth element, an s2 configuration ion, or a transition metal; and (iii) a composite luminescent particle further comprising a coating of an oxide material having a melting point of 700°C or higher, wherein the oxide material is selected from the group consisting of silicon oxide, aluminum oxide, phosphate, or magnesium oxide. The D of the composite light-emitting particles measured by a transmission electron microscope (TEM) ５０ A composite light-emitting particle with a value between 1 nm and 100 μm.

2. The first light-emitting material is capable of emitting light in a first wavelength range, and the second light-emitting material is capable of absorbing light in a second wavelength range and has an emission spectrum that at least partially overlaps with one or more excitation bands of the first light-emitting material. Preferably, the composite light-emitting particle according to claim 1, wherein the first light-emitting material and the second light-emitting material are arranged relative to each other to enable non-radiative energy transfer from the second light-emitting material to the first light-emitting material.

3. The first and second light-emitting materials each form regions within the oxide material, and these regions have bulk, with the minimum dimension of the region measured by a transmission electron microscope (TEM) being D ５０ The composite light-emitting particle according to claim 2, wherein the value is 0.5 nm or more and 100 nm or less, more preferably 0.5 nm or more and 50 nm or less, and most preferably 0.5 nm or more and 10 nm or less.

4. The D of the composite light-emitting particles measured by a transmission electron microscope (TEM) ５０ The composite light-emitting particle according to claim 1, wherein the value is 1 nm or more and 50 μm or less, more preferably 20 nm or more and 10 μm or less, and most preferably 50 nm or more and 10 μm or less.

5. (i) A first luminescent material which is a fluorescent material doped with a rare earth element, an s2 configuration ion, or a transition metal; (ii) A luminescent composition comprising a second luminescent material which is a fluorescent material doped with a rare earth element, an s2 configuration ion, or a transition metal, (iii) At least one of the first or second light-emitting material is contained in particles coated with an oxide material having a melting point of 700°C or higher, wherein the oxide material is selected from the group consisting of silicon dioxide, aluminum oxide, phosphate, or magnesium oxide, and the D of the coated particles measured by a transmission electron microscope (TEM) ５０ The value is between 1 nm and 100 μm. Preferably, the first light-emitting material is capable of emitting light in a first wavelength range, and the second light-emitting material is capable of absorbing light in a second wavelength range and has an emission spectrum that at least partially overlaps with one or more excitation bands of the first light-emitting material. More preferably, the first light-emitting material and the second light-emitting material are arranged relative to each other to enable non-radiative energy transfer from the second light-emitting material to the first light-emitting material in a light-emitting composition.

6. The first light-emitting material and / or the second light-emitting material is selected from the group consisting of oxides, fluorides, nitrides, borates, garnets, molybdates, phosphates, vanadates, chlorides, sulfides, selenides, silicates, aluminates, oxyfluorides, oxychlorides, oxynitrides, oxysulfides, oxyseleniums, fluorinated chlorides, fluorinated silicates, and fluorinated bromides, or combinations thereof. Preferably, selected from the group consisting of oxides, garnets, phosphates, vanadates, or combinations thereof, More preferably, Y ３ Al ５ O １２ , Lu ３ Al ５ O １２ , Y ２ O ３ , YVPO ４ , YVO ４ Or LaPO ４ , or a combination thereof, the composite luminescent particles according to claim 1, or the luminescent composition according to claim 5.

7. The oxide material is selected from the group consisting of silica, alumina, magnesium oxide, and phosphate, as a composite light-emitting particle according to claim 1, or as a light-emitting composition according to claim 5.

8. a) (i) a first luminescent material or a precursor of the first luminescent material, which is a fluorescent material doped with a rare earth element, an s2 configuration ion, or a transition metal; (ii) a second luminescent material or a precursor of the second luminescent material, which is a fluorescent material doped with a rare earth element, an s2 configuration ion, or a transition metal; (iii) a step of further preparing a precursor of an oxide material, wherein the melting point of the oxide material is at least 700°C, and the oxide material is selected from the group consisting of silicon oxide, aluminum oxide, phosphate, or magnesium oxide. b) A step of mixing the first light-emitting material or its precursor, the second light-emitting material or its precursor, and the oxide material precursor, c) A step of curing the precursor of the oxide material to obtain cured particles, wherein the cured particles contain the first light-emitting material or its precursor, the second light-emitting material or its precursor, and a coating of the oxide material, d) A step of heating the cured particles to at least 200°C, A method for producing composite light-emitting particles containing [the specified element].

9. The method according to claim 8, wherein the first light-emitting material is capable of emitting light in a first wavelength range, and the second light-emitting material is capable of absorbing light in a second wavelength range and has an emission spectrum that at least partially overlaps with one or more excitation bands of the first light-emitting material.

10. The method according to claim 8, wherein step b) of the method is performed in a single step so that a single mixture is formed.

11. Step b) of the above method is b1) A step of mixing the first light-emitting material or its precursor with the oxide material precursor in a first container, and mixing the second light-emitting material or its precursor with the oxide material precursor in a second container. b2) If necessary, a step of at least partially curing at least one of the obtained mixtures, b3) If necessary, a step of mixing the at least partially cured mixture, The method according to claim 8, including the method described in claim 8.

12. a) (i) Prepare a first luminescent material or a precursor of the first luminescent material, which is a fluorescent material doped with a rare earth element, an s2 configuration ion, or a transition metal; (ii) Prepare a second luminescent material or a precursor of the second luminescent material, which is a fluorescent material doped with a rare earth element, an s2 configuration ion, or a transition metal; (iii) Prepare a precursor of an oxide material, wherein the melting point of the oxide material is at least 700°C, and the oxide material is selected from the group consisting of silicon oxide, aluminum oxide, phosphate, or magnesium oxide. b) A step of mixing either the first light-emitting material or its precursor or the second light-emitting material or its precursor with the oxide material precursor, c) A step of curing the precursor of the oxide material to obtain cured particles, wherein the cured particles contain either the first light-emitting material or its precursor or the second light-emitting material or its precursor, and a coating of the oxide material. d) A step of mixing the cured particles with the remaining luminescent material or its precursor, wherein the remaining luminescent material or its precursor is, if necessary, coated with an oxide material having a melting point of at least 700°C, and e) A step of heating the mixture to at least 200°C. A method for producing a light-emitting composition containing, A method for manufacturing a first light-emitting material that can emit light in a first wavelength range, and a second light-emitting material that can absorb light in a second wavelength range and has an emission spectrum that at least partially overlaps with one or more excitation bands of the first light-emitting material.

13. The method according to claim 8, wherein the precursor of the oxide material is selected from the group consisting of organic silicate esters, silicon salts, aluminum salts, phosphates, and magnesium salts, preferably the salt is selected from nitride salts or chloride salts, and / or the precursor is an ester of orthosilicic acid, and / or step c) comprises a hydrolysis reaction, preferably the oxide material is silica, and step c) comprises adding ammonia to cure the precursor of the oxide material.

14. The aforementioned heating is carried out in a reducing atmosphere, at least partially. The heating includes heating to at least 500°C, preferably at least 600°C, preferably less than 2000°C, more preferably less than 1500°C, and / or The method according to claim 8, wherein the heating includes heating for at least 1 minute, preferably at least 5 minutes. 【Request Item 15】 The first light-emitting material or its precursor, and / or the second light-emitting material or its precursor, are provided as particles, and the minimum dimension of the particles measured by a transmission electron microscope (TEM) is D ５０ The method according to any one of claims 8 to 14, wherein the value is 0.5 nm or more and 100 nm or less, preferably 0.5 nm or more and 50 nm or less, more preferably 0.5 nm or more and 10 nm or less.

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