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CN-121986148-A - Method for treating luminescent nanoparticles

CN121986148ACN 121986148 ACN121986148 ACN 121986148ACN-121986148-A

Abstract

The invention provides a composite luminescent particle providing method, which comprises (a) providing (i) luminescent materials comprising (A 1‑x B x ) 3 (C 1‑y D y ) 5 O 12 nano particles or precursors thereof, wherein A comprises one or more of yttrium, lutetium, gadolinium and lanthanum, B comprises one or more rare earth elements, C comprises one or more of aluminum, gallium and scandium, D comprises one or more transition metal ions, 0≤x≤1, 0≤y≤1, x+y >0, and (ii) further providing oxide material precursors, wherein the melting point of the oxide material is at least 850 ℃, mixing (B) luminescent materials comprising (A 1‑x B x ) 3 (C 1‑y D y ) 5 O 12 nano particles or precursors thereof and (ii) oxide material precursors, (C) curing the oxide material precursors to obtain cured particles, wherein the cured particles comprise luminescent materials and oxide material coating layers, (D) heating the cured particles at a first temperature above 600 ℃ for a first time period of more than 10 minutes, and (C) heating the cured particles at a second temperature above 700 ℃ for a second time period of more than 1 hour under a reducing atmosphere comprising carbon monoxide.

Inventors

  • A. D. Songtak
  • M. A. van der Hare
  • F. Montanarella
  • V. M. Hanning

Assignees

  • 西博勒材料IP有限公司

Dates

Publication Date
20260505
Application Date
20240920
Priority Date
20230920

Claims (17)

  1. 1. A method of providing composite luminescent particles, comprising: (a) Providing (i) a luminescent material comprising (A 1-x B x ) 3 (C 1-y D y ) 5 O 12 nanoparticles, wherein A comprises one or more of yttrium, lutetium, gadolinium, lanthanum, B comprises one or more rare earth elements, C comprises one or more of aluminum, gallium, scandium, D comprises one or more transition metal ions, and wherein 0≤x≤1, 0≤y≤1, and x+y >0, and (ii) further providing a precursor of an oxide material, wherein the oxide material has a melting point of at least 850 ℃; (b) Mixing (i) a luminescent material comprising (a 1-x B x ) 3 (C 1-y D y ) 5 O 12 nanoparticles with (ii) a precursor of the oxide material; (c) Curing the precursor of the oxide material to obtain cured particles, the cured particles comprising the luminescent material, and a coating of the oxide material; (d) Heating the cured particles at a first temperature for a first period of time, wherein the first temperature is 600 ℃ or greater, wherein the first period of time is 10 minutes or greater, and (E) Heating the cured particles at a second temperature under a reducing atmosphere comprising carbon monoxide for a second period of time, wherein the second temperature is 700 ℃ or greater, and wherein the second period of time is 1 hour or greater; wherein preferably the (a 1-x B x ) 3 (C 1-y D y ) 5 O 12 nanoparticles are obtained by solvothermal method, more preferably by alcohol-thermal method.
  2. 2. A method of obtaining a composite luminescent particle, comprising: (a) Providing (i) (a 1-x B x ) 3 (C 1-y D y ) 5 O 12 nanoparticle precursor material, wherein a comprises one or more of yttrium, lutetium, gadolinium, lanthanum, B comprises one or more rare earth elements, C comprises one or more of aluminum, gallium, scandium, D comprises one or more transition metal ions, and wherein 0≤x≤1, 0≤y≤1, and x+y >0, and (ii) further providing a precursor of an oxide material, wherein the oxide material has a melting point of at least 850 ℃; (b) Mixing (i) a precursor material of (a 1-x B x ) 3 (C 1-y D y ) 5 O 12 with (ii) a precursor of the oxide material; (c) Curing the precursor of the oxide material to obtain cured particles comprising the (a 1- x B x ) 3 (C 1-y D y ) 5 O 12 precursor material, and a coating of the oxide material; (d) Heating the cured particles at a first temperature for a first period of time, wherein the first temperature is 800 ℃ or greater and the first period of time is 10 minutes or greater, and (E) Heating the cured particles at a second temperature under a reducing atmosphere comprising carbon monoxide for a second period of time, wherein the second temperature is 700 ℃ or greater, and wherein the second period of time is 1 hour or greater; wherein the precursor material is preferably obtained by precipitation.
  3. 3. The method according to claim 1 or 2, wherein: B comprises one or more of cerium, terbium and europium, Preferably, wherein B comprises cerium and C comprises aluminum.
  4. 4. A method according to any one of claims 1-3, wherein: -the first temperature is 800 ℃ or higher, preferably 900 ℃ or higher, and preferably 1500 ℃ or lower, more preferably 1250 ℃ or lower; The first time period is 10 minutes or more, preferably 1 hour or more, and preferably 8 hours or less, more preferably 5 hours or less, most preferably 3 hours or less, and/or -Wherein heating the mixture at a first temperature for a first period of time is performed in an atmosphere, wherein the atmosphere is air or an inert gas.
  5. 5. The method of any one of claims 1-4, wherein: -the second temperature is 750 ℃ or higher, and preferably 1150 ℃ or lower; -said second time period is 8 hours or more, preferably 16 hours or more, more preferably 24 hours or more, and preferably 40 hours or less, more preferably 30 hours or less.
  6. 6. The method of claim 5, wherein heating under a reducing atmosphere is performed by placing the mixture in a first crucible contained in a closed second crucible that also contains a carbon source.
  7. 7. The method according to any one of the preceding claims, wherein the precursor of the oxide material is selected from the group consisting of organosilicates, silicon salts, aluminum salts, phosphate salts and magnesium salts, preferably wherein the salt is selected from the group consisting of nitride salts or halide salts and/or the precursor is an orthosilicate, and/or wherein step c) comprises a hydrolysis reaction, preferably wherein the oxide material is silica, and step c) comprises adding ammonia to cure the precursor of the oxide material.
  8. 8. A method according to any one of the preceding claims, wherein in step (a) there is further provided (iii) other luminescent materials comprising rare earth, s2 configuration ion or transition metal doped phosphor materials or precursors thereof; preferably, wherein the doped phosphor material comprises an oxide, fluoride, nitride, borate, garnet, molybdate, phosphate, vanadate, chloride, sulfide, selenide, silicate, aluminate, oxyfluoride, oxychloride, oxynitride, oxysulfide, oxyselenide, fluorochloride, fluorosilicate, and fluorobromide or a combination thereof, More preferably selected from the group consisting of oxides, garnet, phosphate, vanadate or combinations thereof, Most preferably selected from 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.
  9. 9. The method of claim 9, wherein step b) is performed in a single step such that a single mixture is formed, or wherein method step b) comprises: b1 Mixing (i) the luminescent material comprising (a 1-x B x ) 3 (C 1-y D y ) 5 O 12 nanoparticles or the precursor material of (a 1- x B x ) 3 (C 1-y D y ) 5 O 12 nanoparticles) with (ii) the precursor of the oxide material in a first container and (iii) the other luminescent material or the precursor material thereof with (ii) the precursor of the oxide material in a second container; b2 Optionally, at least partially curing at least one of the resulting mixtures, and B3 Mixing the optionally at least partially cured mixture.
  10. 10. The method according to any of the preceding claims, further comprising at least partially removing the oxide material, preferably by grinding or etching, wherein the etching is preferably NaOH etching, preferably further comprising heating the particles at a third temperature for a third period of time under a reducing atmosphere after at least partially removing the oxide material, wherein the third temperature is 500 ℃ or higher, and wherein the third period of time is 1 hour or longer.
  11. 11. A composite luminescent particle obtained by the method according to any one of the preceding claims, comprising (i) (A 1-x B x ) 3 (C 1-y D y ) 5 O 12 nanoparticles, wherein A comprises one or more of yttrium, lutetium, gadolinium, lanthanum, B comprises one or more rare earth elements, C comprises one or more of aluminum, gallium, and scandium, D comprises one or more transition metal ions, and 0≤x≤1, 0≤y≤1, and x+y >0, and (ii) a coating of an oxide material having a melting point of 850 ℃ or higher, the composite luminescent particle having: -a photoluminescence quantum yield of more than 60%, preferably more than 80%; -storage light stability such that the photoluminescence intensity after two weeks of storage in a non-inert atmosphere is at least 80% of the initial photoluminescence intensity; Light stability under light such that at a suitable excitation wavelength at light > 0.1W/cm 2 at least 50% of the initial photoluminescent intensity remains after 10 hours, preferably at least 50% of the initial photoluminescent intensity remains after 15 hours, and When B comprises cerium, the peak ratio in the excitation spectrum (between 455 nm and 380 nm) is greater than 20.
  12. 12. A composite luminescent particle obtainable by the process according to claim 10, comprising (i) (a 1-x B x ) 3 (C 1-y D y ) 5 O 12 nanoparticles, wherein a comprises one or more of yttrium, lutetium, gadolinium, lanthanum, B comprises one or more rare earth elements, C comprises one or more of aluminum, gallium and scandium, D comprises one or more transition metal ions, and 0≤x≤1, 0≤y≤1, and x+y >0, and (ii) a coating of an oxide material having a melting point of 850 ℃ or higher, wherein the thickness of the coating is greater than 0nm and less than 5 nm; preferably, wherein the composite luminescent particle has: -a photoluminescence quantum yield of more than 60%, preferably more than 80%; -storage light stability such that the photoluminescence intensity after two weeks of storage in a non-inert atmosphere is at least 80% of the initial photoluminescence intensity; Light stability under light such that at a suitable excitation wavelength at light > 0.1W/cm 2 at least 50% of the initial photoluminescent intensity remains after 10 hours, preferably at least 50% of the initial photoluminescent intensity remains after 15 hours, and Preferably, when B comprises cerium, the peak ratio in the excitation spectrum (between 455 nm and 380 nm) is greater than 20.
  13. 13. The composite luminescent particle according to claim 11 or 12, wherein a comprises at least one selected from the group consisting of yttrium, lutetium, B comprises at least one of cerium, terbium and europium, preferably wherein C is aluminum, B is cerium, europium, terbium or a combination of terbium and europium: When B comprises cerium, the molar concentration of cerium is between 0.05 and 5% based on the combined total of a and B; When B comprises europium, the molar concentration of europium is 0.1-20% based on the combined total of A and B, and/or Preferably, when B comprises terbium, the molar concentration of terbium is 20-100% based on the combined total of a and B.
  14. 14. Luminescent particle, preferably obtainable by the process of claim 10, wherein the luminescent particle comprises (i) at least one (A 1-x B x ) 3 (C 1-y D y ) 5 O 12 nanoparticle wherein A comprises yttrium, preferably consists of yttrium, (B comprises cerium and terbium, preferably consists of cerium and terbium, (C comprises aluminum, preferably consists of aluminum, (D) comprises one or more transition metal ions, and 0< x≤1, 0≤y≤1, and x+y >0, Wherein: -cerium in a molar concentration of 0.05-5% based on the combined total of a and B; The molar concentration of terbium is 20 to 100%, preferably 55 to 95%, more preferably 60 to 90% based on the combined total of A and B; The particle size of the luminescent particles is preferably such that the longest diameter D 50 value is not less than 0.5 nm and not more than 50 nm, more preferably not less than 0.5 nm and not more than 30 nm, even more preferably not less than 0.5 nm and not more than 20 nm, and.
  15. 15. The luminescent particle according to claim 14, wherein the luminescent particle has: -a photoluminescence quantum yield of more than 60%, preferably more than 80%; -storage light stability such that the photoluminescence intensity after two weeks of storage in a non-inert atmosphere is at least 80% of the initial photoluminescence intensity; Light stability under light such that at a suitable excitation wavelength at light > 0.1W/cm 2 at least 50% of the initial photoluminescent intensity remains after 10 hours, preferably at least 50% of the initial photoluminescent intensity remains after 15 hours, and -Peak ratio in the excitation spectrum (between 455 nm and 380 nm) of greater than 20.
  16. 16. A luminescent composition comprising a first luminescent material and a second luminescent material, wherein at least one of the first luminescent material and the second luminescent material comprises a composite luminescent particle according to any one of claims 11-13, or a luminescent particle according to any one of claims 14-15, Preferably, wherein the first luminescent material is capable of emitting light in a first wavelength range, the second luminescent material is capable of absorbing light in a second wavelength range and has an emission spectrum at least partially overlapping with one or more excitation bands of the first luminescent material, more preferably, wherein the first luminescent material and the second luminescent material are arranged to each other allowing non-radiative energy transfer from the second luminescent material to the first luminescent material, More preferably, wherein the first luminescent material and the second luminescent material each comprise a material selected from composite luminescent particles according to any one of claims 11-13, or luminescent particles according to any one of claims 14-15.
  17. 17. A luminescent composition obtained by the method according to any one of claims 9-10, comprising (i) a first luminescent material comprising (a 1-x B x ) 3 (C 1-y D y ) 5 O 12 nanoparticles; and (ii) a second luminescent material comprising nanoparticles of rare earth, s2 configuration ion or transition metal doped phosphor material; preferably, wherein the first luminescent material is capable of emitting light in a first wavelength range, the second luminescent material is capable of absorbing light in a second wavelength range and has an emission spectrum at least partially overlapping with one or more excitation bands of the first luminescent material, more preferably wherein the first luminescent material and the second luminescent material are arranged to each other allowing non-radiative energy transfer from the second luminescent material to the first luminescent material.

Description

Method for treating luminescent nanoparticles Technical Field The present invention relates to the treatment of luminescent nanoparticles. The invention also relates to obtaining luminescent nanoparticles from precursor particles. The invention also relates to the luminescent nanoparticles treated or obtained. The invention also relates to luminescent compositions comprising the treated or obtained luminescent nanoparticles, and to methods of preparing the luminescent compositions. The invention also relates to applications and devices comprising the luminescent nanoparticle or luminescent composition of the invention. Background Luminescent down-conversion materials play an important role in solid state lighting devices for lighting and real world applications, among others. Such materials may also be used as tracers, for example for security inks. Nanomaterials are of great interest because of their small size. In theory, the nanoparticles would be readily applicable to a variety of applications. However, suitable nanomaterials can be poor in quality (chemical, stability, optical and/or physical) due to their small size and poor crystallinity. WO2021043762A1 teaches annealing nanoparticles to improve lattice densification (quality), uniformity and phase purity as well as photoluminescence properties. However, further improvements are still needed. Cerium doped yttrium aluminum garnet (YAG: ce) is the reference phosphor for solid state LED lighting. YAG: ce is very efficient in microcrystalline form (or as bulk single crystal/ceramic), however, at the nanoscale it generally suffers from weak emission intensity, low conversion efficiency and poor stability, mainly due to the high specific surface area of the nanoparticles and the associated poor uniformity of Ce in the nanoparticle lattice. Wet chemical synthesis (solvothermal, precipitation, sol-gel, etc.) provides YAG: ce nanoparticles with dimensions as low as 5 nm a. Such synthetic nano-YAG: ce may contain impurity phases, weaker crystal lattices, and poorer Photoluminescence (PL) properties. Revaux et al, nanoscale, 2011, 3, 2015-2022 disclose solvothermal synthesis of YAG: ce nanoparticles, which are subsequently incorporated into a porous silica matrix, followed by drying and grinding. The powder was then annealed in air at 1000 ℃ for 12 hours and in Ar/10% H 2 at 600 ℃ for 12 hours. The photoluminescence quantum yield (PLQY) of the final material was reported to be about 60%. PL stability is also improved compared to the solvothermal precursor nanoparticles just synthesized (as-synthesized). WO2018/167266 discloses a composition comprising a luminescent material and a sensitizer material, wherein the luminescent material and the sensitizer material are selected such that the sensitizer has an emission spectrum that at least partially overlaps with one or more excitation bands of the luminescent material, and wherein the luminescent material and the sensitizer are arranged to allow non-radiative energy transfer from the sensitizer material to the luminescent material. The application also describes a process for its preparation. Non-radiative energy transfer (sometimes also referred to as fluorescence resonance energy transfer, FRET) from a sensitizer to a luminescent material involves non-radiative transfer of energy from excited sensitizer ions in the sensitizer material to acceptor (or emitter) ions in the luminescent material. This can be verified by an increase in emission of emitter ions from the luminescent material upon selective excitation of sensitizer ions in the sensitizer material. Nanomaterials are of great interest because of their high specific surface area and small volume, which enables the luminescent materials to be closely spaced to exploit inter-particle FRET. In order to be able to effectively utilize inter-particle FRET, the size of the luminescent particles is desirably very small (< 10 nm). Thus, there remains a need for luminescent nanomaterials with improved quality and stability at small dimensions. In addition, there is a need for luminescent compositions exhibiting high photoluminescence Quantum Yields (QY) and improved stability, and methods of making the same. Disclosure of Invention A method of providing composite luminescent particles is provided, comprising: (a) Providing (i) a luminescent material comprising (A 1-xBx)3(C1-yDy)5O12 nanoparticles, wherein A comprises one or more of yttrium, lutetium, gadolinium, lanthanum, B comprises one or more rare earth elements, C comprises one or more of aluminum, gallium, scandium, D comprises one or more transition metal ions, and wherein 0≤x≤1, 0≤y≤1, and x+y >0, and (ii) further providing a precursor of an oxide material, wherein the oxide material has a melting point of at least 850 ℃; (b) Mixing (i) a luminescent material comprising (a 1-xBx)3(C1-yDy)5O12 nanoparticles with (ii) a precursor of the oxide material; (c) Curing the precursor of the oxide material to obtain c