109 results about "Lutetium" patented technology

The invention provides a rare earth silicon germanate scintillating material and a preparation method and application thereof, in particular to a rare earth silicon germanate scintillating material with high thermal stability and strong radiation resistance and a preparation method and application thereof, the general formula of the rare earth silicon germanate scintillating material with high thermal stability and strong radiation resistance is RE2 (1-x-delta / 2) Ce2xGedeltaSi (1-y + delta) Gey-deltaOz, in the formula, 0 lt; x is more than or equal to 0.05, y is more than or equal to 0.15 and less than or equal to 0.5, delta is more than or equal to 0 and less than or equal to 10 <-4 >, z is more than or equal to 4.95 and less than or equal to 5.05, RE represents a rare earth element, and the rare earth element is selected from at least one of lanthanum (La), lutetium (Lu), yttrium (Y) and gadolinium (Gd). The rare earth silicon germanate scintillating material provided by the invention has the characteristics of strong radiation damage resistance, high scintillation light output, low afterglow and the like while greatly improving the thermal stability, and can be used in occasions with extremely high requirements on the thermal stability or radiation resistance of the material, such as high-energy physical experiments, nuclear medicine imaging, oil exploration wells and the like.

The invention relates to the technical field of rare earth element separation methods, in particular to a method for separating ytterbium and lutetium by using a phosphate adsorbent, which comprises the following steps: loading a phosphate solution on a porous solid-phase carrier by using a vacuum impregnation method, and carrying out reduced pressure evaporation and drying to obtain a phosphate solid adsorbent; filling an exchange column with the solid adsorbent to obtain the exchange column filled with the solid adsorbent; enabling a nitric acid solution containing ytterbium and lutetium to flow through an exchange column filled with a solid adsorbent to complete a column adsorption process; and performing elution, performing desorption by using a desorption solution to obtain the regenerated exchange column filled with the solid adsorbent, respectively collecting the ytterbium solution and the lutetium solution, completing the separation process, and repeating the steps. By adopting the steps, the separation of ytterbium and lutetium is directly realized from the nitric acid solution containing ytterbium Yb and lutetium Lu through column adsorption separation, leaching and desorption processes, and high-purity ytterbium and lutetium products are prepared.

The invention relates to a purple light-excited cyan light-emitting fluorescent material as well as a preparation method and application thereof. The cyan light emitting fluorescent material is a Ce < 3 + > doped oxide cyan light emitting fluorescent material, the chemical expression of the cyan light emitting fluorescent material is SrCa0. 7Mg0. 3Lu4-xO8: xCe < 3 + >, and x is more than or equal to 0.003 and less than or equal to 0.05. The preparation method comprises the following steps: weighing a strontium source compound, a calcium source compound, a magnesium source compound, a lutetium source compound and a cerium source compound according to a stoichiometric ratio of a chemical expression of the green light emitting fluorescent material, grinding and uniformly mixing to obtain a mixture; sintering the mixture at high temperature, and cooling to obtain the purple light excited cyan fluorescent material. Compared with the prior art, the method has the advantages of optimizing the crystal field environment, constructing a cyan fluorescent material with wide-spectrum excitation characteristic, high luminous efficiency and excellent thermal stability and the like.

This invention provides a highly conductive preformed solder sheet, comprising a core layer and a shell layer disposed around the core layer. By embedding the solid flux core layer within the solder alloy layer to form a sandwich-like shape, the flux can be effectively protected from oxidation. There is no need to apply flux before brazing or remove it after brazing, reducing manufacturing costs and the void rate on the welded surface, thus improving the reliability of the solder sheet. The solder alloy shell is composed of tin, silver, copper, indium, cerium, vanadium, lutetium, yttrium, and zinc. The addition of small amounts of rare earth elements lutetium, yttrium, and cerium improves the conductivity and heat transfer of the solder sheet. The addition of indium, vanadium, and zinc increases the melting point of the solder sheet and improves its solidification state. Since no magnetic materials such as lead, iron, cobalt, nickel, or niobium are added, signal interference caused by metals is avoided.

The invention discloses a modification method of a ternary positive electrode material. The modification method comprises the following steps: S1, carrying out a co-precipitation reaction on a solution of transition metal sulfate in an inert gas atmosphere; a sulfate solution of rare earth elements is synchronously added in the coprecipitation process, and a ternary precursor with the surface coated with rare earth hydroxide is formed; and S2, mixing the ternary precursor obtained in the step S1 with a lithium source, calcining in an air atmosphere, and cooling to obtain the fast ion conductor coated ternary positive electrode material, the rare earth elements are selected from one or more of lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium; the transition metal sulfate is soluble salt of Ni, Co and Mn. The rare earth element sulfate is added in the coprecipitation process, the rare earth element hydroxide is precipitated on the surface of the precursor, the lithium source is removed after filtering and drying, uniform mixing is performed, and the ternary positive electrode material which contains the rare earth element and is uniformly coated with the fast ion conductor is obtained after calcination, so that side reactions on the surface of the material are reduced; and the cycling stability of the positive electrode material is improved.

The invention relates to a microbial growth activation accelerant based on rare earth elements as well as a preparation method and application thereof, and belongs to the field of resources and environments. The microbial growth activation accelerant based on the rare earth elements is prepared from the following components: 1 to 150g of a rare earth compound, 0.2 to 2g of pantothenic acid, 0.2 to 2g of nicotinic acid, 0.02 to 0.1 g of nicotinamide and 1000g of deionized water, the rare earth compound is one or combination of more of chlorides of lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium and yttrium, nitric acid compounds and sulfuric acid compounds. A large number of cheap light rare earth elements are used as raw materials of the microbial accelerator, a new utilization approach is provided for the light rare earth elements, the light rare earth elements are converted into high-added-value products, pollution of the light rare earth elements to the environment is reduced, and meanwhile new elements are introduced into the field of microbial accelerators. More importantly, the preparation method of the microbial growth activation accelerant based on the rare earth elements provided by the invention is simple in production process and convenient for large-scale production.

The invention discloses a lutetium-calcium-magnesium-aluminum-silicon garnet transparent ceramic material and application thereof in a white-light LED (light-emitting diode). The method comprises the following steps: (1) fusing SiO2, Al2O3, Lu2O3, CaO, MgO and raw materials doped with luminous ions to obtain glass liquid; (2) molding, cooling and annealing the molten glass to obtain a glass precursor; 3) performing heat treatment on the glass precursor to obtain the lutetium calcium magnesium aluminum silicon garnet ceramic; and luminous ions are more than one of Ce, Er, Nd and Cr. The method is simple, the prepared ceramic is good in luminescent property, high in heat conductivity and high in hardness, and the preparation method is simple and low in cost. The method can be used for preparing transparent ceramics with large sizes and various shapes, and is low in cost and easy for industrial production. The ceramic emits bright yellow light under the excitation of 450nm blue light, and the yellow light and the blue light are combined to generate strong white light, so that the ceramic can be used for preparing a white light LED (light-emitting diode).

The invention belongs to the technical field of inorganic scintillator materials, and particularly relates to a multi-element co-doped yttrium lutetium silicate scintillator and a preparation method and application thereof, and the material has excellent comprehensive performance of high light output, short decay time, high radiation hardness, high matching degree of emission spectrum and novel photoelectric sensors and the like. The invention further relates to a preparation method of the scintillator material and application of the scintillator material in radiation detection fields such as positron emission tomography (PET), time flight PET (TOF-PET), interaction depth PET (DOI-PET), single photon emission computed tomography (SPECT), high-energy physical experiments, nuclear medicine imaging, industrial nondestructive inspection, safety detection (such as luggage and cargo container inspection) and the like.

The application belongs to the field of inorganic materials, and particularly relates to a lutetium silicate ceramic material and a method for improving high-temperature water-vapor corrosion resistance of the lutetium silicate material, and is suitable for performance optimization and development and application of rare earth silicate materials for environmental barrier coating. The method comprises the following steps: (1) controlling the content of solvent atoms Ho in Lu2SiO5 according to the stoichiometric ratio; (2) increasing the wetting angle of the Lu2SiO5 ceramic material from 80.1+ / -0.5 degrees to 87.5+ / -0.6 degrees; and (3) reducing the weight loss of the material after corrosion in a water-vapor environment of 1000-1400 DEG C, 30% H2O-70% O2 for 30 hours from 0.221 mg / cm 2 2 to 0.0911 mg / cm 2 2. The application can significantly improve the corrosion resistance of the Lu2SiO5 material in a high-temperature water-vapor environment by designing the composition of Lu2SiO5 through specific rare earth element doping and optimizing the proportion of the doped rare earth elements in Lu2SiO5. Meanwhile, the wetting angle of the Lu2SiO5 material is increased and the hydrophobic property is improved after the rare earth atom solid solution doping, which provides important support for optimizing the high-temperature water-vapor corrosion resistance.

The invention relates to a novel functional material for X-ray protection, in particular to a liquid metal flexible shielding material and a preparation method and application thereof. The material comprises liquid metal and solid metal, the liquid metal serves as a solvent to be filled in gaps of the solid metal, the liquid metal is gallium, gallium indium, gallium indium tin, gallium indium tin zinc or mercury, and the solid metal is selected from one or more of indium, tin, gold, platinum, iridium, zirconium, niobium, molybdenum, ruthenium, osmium, rhenium, rhodium, tungsten, antimony, palladium, tantalum, hafnium, lutetium, lead, ytterbium, thulium, bismuth, silver, erbium, holmium, dysprosium, terbium, gadolinium, samarium, neodymium, lanthanum, praseodymium, cerium and europium. On the basis of compounding of the liquid metal solvent and the solid metal solute based on the liquid metal combinatology, the liquid metal and the solid metal are jointly used for protecting X-ray radiation, the comprehensive performance of X-ray protection is improved, and meanwhile the variety and number range of selectable metal elements is widened.

The present invention provides a method for providing a composite luminescent particle, comprising: (a) providing (i) a luminescent material comprising (A1-xBx) 3 (C1-yDy) 5O12 nanoparticles or a precursor thereof, A comprising 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; 0 < = x < = 1, 0 < = y < = 1, x + ygt; 0; and (ii) also providing an oxide material precursor, the oxide material having a melting point of at least 850 DEG C; (b) mixing (i) a luminescent material comprising (A1-xBx) 3 (C1-yDy) 5O12 nanoparticles or a precursor thereof with (ii) an oxide material precursor; (c) curing the oxide material precursor to obtain cured particles which comprise a luminescent material and an oxide material coating layer; (d) heating the cured particles at a first temperature of 600 DEG C or more for a first duration of 10 minutes or more; and (c) heating the cured particles at a second temperature of 700 DEG C or more for a second duration of 1 hour or more in a reducing atmosphere including carbon monoxide.

The present invention discloses a preparation method and application of a polymer polylactic acid nanocomposite material based on a copper-lutetium metal organic framework (Cu-LU) metal organic framework (MOF), belonging to the technical field of polymer composite materials. The method comprises the following steps: first, adding polylactic acid to dioxane to prepare a uniform polylactic acid solution; second, dispersing copper-lutetium metal organic framework (MOF) nanoparticles in dioxane to prepare a uniform dispersion of the Cu-lutetium metal organic framework (MOF) nanoparticles; third, adding the Cu-lutetium metal organic framework (MOF) nanoparticle dispersion obtained in step two to the polylactic acid solution obtained in step one, stirring at 60°C for 1 hour, obtaining a uniform film-forming solution for later use; and fourth, pouring the film-forming solution obtained in step three into a flat-bottomed glass dish and drying it to obtain a polylactic acid nanocomposite film having both antibacterial and ammonia-responsive functions. The present invention utilizes the above preparation method to obtain a polymer polylactic acid nanocomposite material having excellent water vapor barrier, mechanical strength, UV shielding, blue light shielding, and ammonia-responsive color change properties.

The invention discloses a preparation method of thermal shock resistant Nd: LuAG laser transparent ceramic. The preparation method comprises the following specific steps: weighing lutetium nitrate, aluminum nitrate and neodymium nitrate according to Lu3-xNdxAl5O12, and obtaining nano precursor powder by adopting a solvothermal method; carrying out two-step pre-sintering to form oxide powder with a sub-grain structure; and adding a thermal shock slow-release agent for main sintering, carrying out hot isostatic pressing treatment on the ceramic body after main sintering, and finally annealing in air to obtain the Nd: LuAG transparent ceramic with the density being greater than or equal to 99.9% and the thermal shock resistance temperature difference delta T being greater than or equal to 400 DEG C. The ceramics are particularly suitable for high repetition frequency laser systems.

A method for purifying lutetium includes providing a solid composition comprising ytterbium and lutetium and subliming or distilling ytterbium from the solid composition at a temperature of about 1196° C. to about 3000° C. to leave a lutetium composition comprising a higher weight percentage of lutetium than was present in the solid composition.

The application discloses a method for removing silicon from yttrium lutetium silicate leaching solution, which comprises the following steps: firstly, mixing yttrium lutetium silicate waste with flake alkali uniformly, then baking, adding hot water to stir and react, and filtering to obtain rare earth hydroxide precipitate; then, washing the obtained rare earth hydroxide precipitate with sodium hydroxide solution for 2-3 times; then, placing the treated rare earth hydroxide precipitate in a reaction container, adding a small amount of pure water to stir, heating to 70-90 DEG C under water bath condition, and then keeping constant temperature, then slowly adding hydrochloric acid to dissolve the rare earth hydroxide precipitate to obtain a mixed solution, filtering to remove silicic acid colloid to obtain rare earth leaching solution; then, using an extractant prepared from N235, isooctanol and kerosene to extract the rare earth leaching solution to remove impurity iron, then heating and concentrating to make sodium chloride in the solution precipitate, filtering to remove the precipitated sodium chloride, and finally obtaining pure lutetium yttrium chloride solution. The application can effectively solve the problem that the content of silicon impurities in the yttrium lutetium silicate leaching solution is high and cannot be effectively removed.

The application discloses a lutetium manganate-based near-infrared light detection film, a preparation method and application thereof, and has a molecular formula of Lu (0.98‑x) Er 0.02 Yb x MnO3, wherein x is 0.04-0.10. The application is prepared by rare earth elements Er and Yb co-doping for regulation, and a Lu (0.98‑x) Er 0.02 Yb x MnO3 base film colloid, when x is 0.04-0.10, the optical absorption range is widened and the band gap is reduced, and due to efficient energy transmission between Er 3+ , Yb 3+ , efficient pumping of Er 3+ is realized, thereby enhancing the photovoltaic effect of the LMO film, greatly improving the photoelectric current density, and improving the responsivity and the detection rate by several times under 850 nm near-infrared wavelength. The up-conversion strategy based on multiple rare earth elements co-doping has positive multiple positive effects on the light detection performance, and promotes the development of the ferroelectric series in the field of light detection. Meanwhile, the material is expected to become a new generation of environment-friendly lead-free ferroelectric film material.

Various embodiments include a method of producing purified lutetium-177. The method may include irradiating a target material containing lutetium-176 in a nuclear reactor, separating lutetium-177 from the irradiated target material using electromagnetic isotope separation, dissolving the separated lutetium-177 in an acidic solution, purifying the dissolved lutetium-177 using a series of chromatographic columns and ion resins, and eluting the purified lutetium-177 in a final chemical form suitable for medical use. The chromatographic columns may include a first column containing a lanthanide resin and a second column containing a diglycolamide resin. The final chemical form may be lutetium-177 chloride.

To provide an ScAlN laminate with improved piezoelectric performance.SOLUTION: According to an embodiment of the present invention, there is provided an ScAlN laminate including a substrate, an underlayer formed on the substrate, and an ScAlN thin film formed on the underlayer, and the underlayer is composed of any one of yttrium, lutetium, gadolinium, and cerium. According to an embodiment of the present invention, it is possible to provide an ScAlN laminate with improved piezoelectric performance.SELECTED DRAWING: Figure 1

The invention discloses a preparation method of 5N-grade ultra-pure lutetium oxide, which comprises the following steps: removing thorium and uranium from a lutetium chloride solution, carrying out primary precipitation with oxalic acid, firing to obtain a primary lutetium oxide product, re-dissolving the primary lutetium oxide product with nitric acid, carrying out secondary precipitation with ammonia water, and firing to obtain the 5N-grade ultra-pure lutetium oxide. According to the method disclosed by the invention, the preparation of lutetium oxide with higher purity can be realized by combining extraction with impurity grading removal of oxalic acid-ammonia water double precipitation so as to meet quality index requirements required by application of materials with higher performance. The preparation method is high in stability, high in yield and suitable for industrial production and application.

Provided is an aluminum alloy powder comprising 0.1-2.0 mass% or one or more metal elements from among rare earth metal elements comprising the lanthanide elements and yttrium, wherein the iron content is suppressed to not more than 2.0 mass%. The rare earth metal element is preferably one of praseodymium, neodymium, europium, samarium, terbium, gadolinium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium.

The application relates to the technical field of ceramic compositions, and discloses an X7R type MLCC anti-aging ceramic dielectric material and a preparation method thereof, which comprises barium titanate, magnesium oxide, lutetium oxide, manganese dioxide and glass frit; wherein magnesium ions and lutetium ions occupy titanium positions on the surface layer of the barium titanate crystal lattice and combine with oxygen vacancies to generate ternary composite defect clusters; the ternary composite defect clusters are locally distributed in the shell layer region of the barium titanate crystal grain and are used for improving the long-range electric migration activation energy of the oxygen vacancies; through the construction of an ion and electron double shielding network, the directional migration of the oxygen vacancies under high-temperature direct current bias is inhibited, the contradiction between the conventional anti-aging means and the dielectric constant maintenance is solved, the high dielectric activity of the polarization area of the barium titanate is ensured, the high-temperature insulation reliability of the ceramic dielectric material is enhanced, and the capacitance aging process is delayed.

This application belongs to the field of renewable resource recycling technology, and particularly relates to a method for separately recovering gallium and lutetium from gallium-lutetium garnet waste. The method provided by this application separates gallium and lutetium into a water leaching solution and a water leaching residue after alkaline melting. Subsequently, the water leaching solution is subjected to silicon and aluminum removal to precipitate gallium hydroxide. The water leaching residue is then acid-leached, and the acid leaching solution is extracted to remove iron, purified by extraction, and back-extracted. An excess of oxalic acid is added to ensure that lutetium is fully precipitated in the lutetium-rich back-extraction solution after back-extraction. The lutetium oxalate precipitate is then calcined to obtain lutetium oxide, thereby realizing the separate recovery of gallium and lutetium from gallium-lutetium garnet waste and solving the technical problem of the lack of a method for separately recovering gallium and lutetium from gallium-lutetium garnet in the prior art.

The invention relates to a processing method of a lutetium yttrium silicate crystal. The processing method comprises the following steps: selecting a polishing solution; adding a dispersing agent and a pH regulator into the polishing solution; fixing the cut yttrium lutetium silicate crystal on processing equipment; through the steps of the rough polishing stage, the fine polishing stage and the post-treatment stage, the nanoscale surface shape precision RMS can be better than 0.5 nm, the sub-nanoscale surface roughness Ra is smaller than or equal to 0.55 nm, the surface quality of the LYSO crystal is remarkably improved, and the problem that at present, the surface roughness Ra is smaller than or equal to 0.55 nm is solved. The polishing technology for the LYSO crystal mainly comprises traditional mechanical polishing, chemical mechanical polishing is difficult to meet the requirements of the LYSO crystal for high-precision machining and difficult control of technological parameters, the use of chemical reagents may cause pollution to the environment, and the adaptability is poor when the LYSO crystal is in a complex shape. And high-precision deterministic processing cannot be realized.

This invention provides a method for recovering rare earth elements from lutetium yttrium silicate crystal waste and its application. The method includes the following steps: mixing lutetium yttrium silicate crystal waste with an alkaline substance for alkali fusion, followed by water leaching and acid leaching to obtain an acid leaching solution; mixing the acid leaching solution with an inorganic polymer flocculant and an alkaline solution for preliminary desiliconization to obtain a first desiliconized solution; mixing the first desiliconized solution with a phosphorus-based extractant for extraction to remove impurities, obtaining an extract and a raffinate; performing deep desiliconization on the raffinate using resin adsorption or heteropolyacid extraction to obtain a second desiliconized solution; mixing the second desiliconized solution with a precipitant solution for precipitation to obtain a precipitate product, and then calcining the precipitate product to obtain rare earth oxides. This method can reduce the silicon content to below 1 mg / L, comprehensively recover rare earth elements such as Y and Lu, effectively reduce acid and alkali consumption, improve the comprehensive utilization rate of waste materials, and increase economic benefits.

The application belongs to the field of new materials, and specifically discloses a high-temperature-resistant high-remanence rare earth permanent magnet material and a preparation process thereof. The raw materials comprise, by weight, 24-34 parts of neodymium, 4-7 parts of dysprosium, 0.1-0.5 parts of lutetium (in the form of lutetium fluoride nano powder), 0.5-2 parts of niobium, 0.3-1 part of molybdenum, 58-68 parts of iron, 0.9-1.3 parts of boron, 0.2-0.8 parts of gallium oxide and 0.1-0.6 parts of copper. The grain boundary thermal stability is optimized through lutetium fluoride / niobium / molybdenum synergy, and the defects of traditional neodymium-iron-boron magnets, such as fast high-temperature remanence attenuation and poor coercive force temperature coefficient, are overcome by combining deep cooling treatment with argon-hydrogen mixed atmosphere step sintering process. The obtained magnet has a remanence retention rate of more than 87% at 250 DEG C, and a long-term aging magnetic flux loss of less than 2.5% at 200 DEG C, and is suitable for high-temperature scenes such as automobile motor rotors. A surface plasma electrolytic oxidation coating can further endow excellent corrosion resistance.

An yttrium-containing structure comprises: (a) a substrate layer comprising a metal alloy, a ceramic material, a ceramic composite, or a combination thereof; (b) a bond-coat layer disposed on the substrate layer, or on an optional interlayer that is on the substrate layer, wherein the bond-coat layer comprises yttrium and a noble metal selected from the group consisting of platinum, iridium, rhenium, ruthenium, rhodium, osmium, and / or palladium; (c) a thermally grown oxide layer disposed on the bond-coat layer, wherein the thermally grown oxide layer comprises yttrium oxide; and (d) optionally, a top-coat layer disposed on the thermally grown oxide layer, wherein the top-coat layer comprises a metal oxide, a metal pyrochlore, or a metal silicate. Yttrium may be replaced with lutetium, in which the bond-coat layer comprises lutetium and a noble metal (e.g., Pt or Ir). A mixture of yttrium and lutetium may also be employed.

The present invention relates to the technical field of inorganic luminescent materials, and in particular to a lutetium calcium indium gallium zirconium garnet-based blue light phosphor and its application. The chemical composition of the phosphor is represented by: Lu 2(1‑x) Tm 2x CaInGa3ZrO 12 , where 0≤x<1; the synthesis of the phosphor only requires 3 to 4 hours of reaction to form a phase, and the synthesis process has no specific pressure or atmosphere requirements, which has the advantages of a simple preparation process and low energy consumption. The obtained product has good crystallinity, high luminescence brightness, and a short fluorescence lifetime. The phosphor is excited by ultraviolet light between 350 and 370 nm, and the emission peak is blue light between 430 and 475 nm. It can be used in the field of oral light curing and blue light conversion materials excited by ultraviolet LED chips; the luminescence can continue after the end of X-ray irradiation, with an afterglow luminescence time of 5 seconds, and can be applied to the fields of high-energy ray detection and luminous anti-counterfeiting identification.

The invention discloses a Yb-alpha-beta-Sialon composite ceramic and a preparation method thereof, and belongs to the technical field of ceramic processing, and the Yb-alpha-beta-Sialon composite ceramic comprises the following components: Si3N4, Al2O3, AlN, Yb2O3, Lu2O3, nano SiC whisker, Ti3SiC2, a liquid metal gallium indium tin alloy, a bonding aid and a sintering aid. Double rare earth stabilizers (ytterbium and lutetium) are introduced, the radius of ytterbium ions is large, and an alpha-Sialon phase is mainly stabilized; the lutetium ions are small in radius and mainly stabilize the beta-Sialon phase, the combination can more effectively enter lattice vacancies of different crystal phases, the grain boundary migration speed is restrained, and excessive growth of grains is hindered.

The invention relates to a method for preparing rare-earth metal doped garnet nanoparticles, comprising the steps of: (a) providing (i) a first metal salt and / or alkoxide, wherein said first metal is one or more of yttrium, lutetium, gadolinium and lanthanum, (ii) a second metal salt and / or alkoxide, wherein said second metal is one or more of aluminum, gallium and scandium, (iii) a third metal salt and / or alkoxide, wherein said third metal is at least one optically active ion, and (iv) a solvent mixture comprising a glycol and a further alcohol; (b) preparing a reaction mixture comprising said (i) first metal salt and / or alkoxide, said (ii) second metal salt and / or alkoxide, said (iii) third metal salt and / or alkoxide, and said (iv) solvent mixture; and (c) heating the reaction mixture, wherein the heating conditions are characterized in that: the pressure during heating is in the range of 20-200 bar, and the reaction mixture is heated at 300-400 °C for 120 minutes or less. The invention further relates to rare-earth metal doped garnet nanoparticles obtainable by the method of the invention, having the having the structure of (M11-xM3x)3(M2)5O12, wherein M1 is one or more of yttrium, lutetium, gadolinium and lanthanum; M2 is one or more of aluminum, gallium and scandium; and M3 is one or more optically active ions, characterized by: i. a mean particle size D50 of 10 nm or less, preferably 8 nm or less, and preferably 1 nm or more; and ii. a QY of 60% or more, preferably 80% or more.