Preparation method and application of submicron cerium-doped yttrium aluminum garnet powder material

Abstract

The invention relates to a preparation method and application of a submicron cerium-doped yttrium aluminum garnet powder material. The preparation method comprises the following steps: mixing yttrium salt, aluminum salt, cerium salt and a solvent to obtain a metal ion salt solution; mixing the metal ion salt solution with a high-molecular polymer, and carrying out a heating reaction to obtain a precursor powder material; and calcining the precursor powder material to obtain the cerium-doped yttrium aluminum garnet powder material with the submicron size, the mixed solvent comprises an alcohol organic solvent and water. A hydrothermal alcohol solvent thermal synthesis method is adopted, a mixed solvent formed by mixing an alcohol organic solvent and water is used, nucleation and growth of an yttrium aluminum garnet precursor are controlled, and after high-temperature calcination, the submicron cerium-doped yttrium aluminum garnet powder material with nearly spherical morphology, narrow particle size distribution and uniform morphology is obtained. The wide range of the size from 70nm to 1000nm can be regulated and controlled, and meanwhile, the high-efficiency luminous efficiency is realized.

Description

Technical Field

[0001] The invention relates to the technical field of fluorescent materials, and in particular to a preparation method and application of a submicron-sized cerium-doped yttrium aluminum garnet powder material. Background Art

[0002] Yttrium aluminum garnet (chemical formula is Y 3 Al 5 O 12 YAG (YAG) crystal has a cubic crystal structure and has excellent physical and chemical stability. It is an excellent optical matrix material. 3+ The doped yttrium aluminum garnet phosphor has excellent luminescence performance, with the best excitation spectrum peak at 450nm and the best emission spectrum at the yellow broad peak at 540nm. Based on the research and development of blue light chips (InGaN), its 450nm blue light can well match the excitation spectrum of YAG, which is the most commonly used combination of white light LEDs, forming cold white light for lighting. This combination has the advantages of energy saving, high efficiency and environmental protection.

[0003] Due to the poor thermal conductivity of YAG phosphor materials, heat accumulation occurs under outdoor high-power lighting conditions, which seriously hinders the further application of YAG phosphor materials. YAG transparent ceramics can make up for the shortcomings of insufficient thermal conductivity of powder materials and realize the application of high-power scenarios. 3+ Doped yttrium aluminum garnet single crystal materials and transparent ceramic materials can be used in the field of scintillation luminescence and are one of the key materials for high-energy ray imaging. However, due to the difficulty in growing single crystals, yttrium aluminum garnet single crystal materials are expensive and difficult to use on a large scale. However, yttrium aluminum garnet transparent ceramics made by sintering powders are competitive substitutes for corresponding single crystal materials and can replace them in the fields of high-power luminescence and laser luminescence. High-quality powders are one of the necessary conditions for the preparation of transparent ceramics. Currently, the preparation of high-quality Ce 3+ The sintering of doped yttrium aluminum garnet powder materials into transparent ceramics is a pain point and difficulty in the industry.

[0004] At present, the main synthesis methods for preparing yttrium aluminum garnet powder are based on high temperature solid phase synthesis method, gas phase synthesis method and liquid phase synthesis method. High temperature solid phase synthesis method is the traditional YAG preparation method, which uses metal oxides or carbonates in a certain proportion to react at high temperature and obtain Ce 3+ Doped YAG powder. The high-temperature solid-phase synthesis method requires a higher calcination temperature, and the resulting product powder size is also larger, usually above 10μm, and even up to 50μm. Such large-sized YAG: Ce 3+The powder material itself is a fluorescent light conversion material with excellent luminescence performance, but its sintering performance is low, making it difficult to use as a raw material and further sinter into transparent ceramics. The YAG powder prepared by the gas phase synthesis method is small in size, usually less than tens of nanometers, and has serious agglomeration, which is not conducive to the sintering of transparent ceramics.

[0005] The precipitation method is a solution-based synthesis method. By using a precipitant such as ammonia or carbonate, the metal ions are precipitated according to a stoichiometric ratio, and then calcined to obtain YAG powder. Because rare earth ions precipitate very quickly under the conditions of the precipitant, small particles are quickly formed, and the small particles then aggregate to form larger secondary particles. The secondary particles have a loose structure, resulting in uneven morphology, extremely wide size distribution, and easy sintering into blocks during the subsequent calcination process. Therefore, it is difficult to obtain uniformly dispersed YAG powder with adjustable size by the precipitation method.

[0006] The hydrothermal and solvothermal synthesis method can obtain YAG powders with relatively uniform morphology and size, but the current hydrothermal and solvothermal methods can only obtain powders of one size, and it is difficult to control the size of the powders in a wide range by adjusting the synthesis parameters. The literature (Ceramics International 38 (2012) 235–242) reported that a 500nm uniform YAG powder was synthesized by a hydrothermal method under ammonia-assisted conditions. Under alkaline conditions, small particles aggregated to form a uniform cubic morphology. However, by adjusting the reaction conditions, it is not only difficult to obtain powders of other sizes, but also difficult to maintain the original uniformity of the morphology.

[0007] Therefore, in view of the application of YAG transparent ceramics, it is urgent and urgently needed by the industry to develop cerium-doped YAG powder with adjustable size and uniform morphology and corresponding synthesis methods. Summary of the invention

[0008] In order to solve the above technical problems, the present invention aims to provide a preparation method and application of a submicron-sized cerium-doped yttrium aluminum garnet powder material. The present invention uses an alcohol thermal reaction to precipitate metal ions in a certain proportion to form a precursor with uniform size and morphology, and then calcines it to obtain a cerium-doped yttrium aluminum garnet phase powder material. 3+ The morphology of the doped YAG powder is nearly spherical, and the size can be adjusted in the range of 70nm to 1000nm with a narrow size distribution. It also has good luminescence performance, with an excitation spectrum peak at 450nm, an emission spectrum peak at 540nm, and a luminescence quantum efficiency of more than 85%.

[0009] To achieve this object, the present invention adopts the following technical solutions:

[0010] In a first aspect, the present invention provides a method for preparing a submicron-sized cerium-doped yttrium aluminum garnet powder material, the preparation method comprising the following steps:

[0011] Mixing yttrium salt, aluminum salt, cerium salt and solvent to obtain a metal ion salt solution; mixing the metal ion salt solution with a high molecular polymer, and heating the mixture to obtain a precursor powder material;

[0012] The precursor powder material is calcined to obtain the submicron-sized cerium-doped yttrium aluminum garnet powder material;

[0013] The mixed solvent includes an alcohol organic solvent and water.

[0014] The present invention utilizes alcohol substances as solvents and reactants. Under heating conditions, alcohol substances have high reaction activity and can control the reaction rate, so that yttrium ions and aluminum ions are precipitated according to a stoichiometric ratio, achieving uniform dispersion of yttrium and aluminum at the atomic scale, which is beneficial to subsequent low-temperature calcination to form a yttrium aluminum garnet phase without phase separation.

[0015] In the traditional precipitation method, yttrium and aluminum are generally precipitated together directly using a precipitant. Since the precipitation speed of rare earth ions under the condition of the precipitant is very fast, small particles are quickly formed, and the small particles are then aggregated to form larger secondary particles. The secondary particles have a loose structure, resulting in uneven morphology and extremely wide size distribution. The method of the present invention can balance the precipitation reaction of metal ions and the growth process of particles under alcohol-heat conditions, so that the small particles after the precipitation reaction can continue to grow on the existing particles to obtain a product with controllable size. The reaction is similar to the Stober reaction process, and a cerium-doped yttrium aluminum garnet powder material with uniform product size and morphology and narrow particle size distribution is obtained.

[0016] The present invention adopts a hydrothermal alcohol solvent thermal synthesis method, uses a mixed solvent formed by mixing an alcohol organic solvent with water, and controls the reaction rate by regulating the alcohol substance and the reaction temperature, thereby achieving the purpose of controlling the nucleation and growth of the yttrium aluminum garnet precursor, and controlling the slow growth of the precursor to achieve controllable synthesis of the precursor particles. The basic principle of the reaction is to generate a base (OH — ), the alkali generated in situ reacts with the metal ions to form metal oxide monomers, the formation rate of the monomers is controlled by the reaction rate, and the nucleation and growth process is controlled. This is significantly different from the traditional method in which an additional alkali is added, and the reaction rate of the alkali and the metal ions and the subsequent products cannot be controlled. The preparation method solves the problems in the prior art that it is difficult to control the particle size, the particle size and morphology are poorly uniform, and the particle agglomeration is easy to occur. In addition, the preparation method provided by the present invention has the characteristics of stable process, large output, strong operability, etc., and can be mass-produced.

[0017] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. Through the following preferred technical solutions, the technical objectives and beneficial effects of the present invention can be better achieved and realized.

[0018] Preferably, the volume ratio of the alcohol organic solvent to water in the mixed solvent is (0.1-2):1, for example, it can be 0.1:1, 0.2:1, 0.3:1, 0.4:1, 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1 or 2:1, but is not limited to the listed values, and other unlisted values ​​within the numerical range are equally applicable.

[0019] Preferably, the alcohol organic solvent includes any one of methanol, ethanol, ethylene glycol, isopropanol, butanol, diethylene glycol or glycerol, or a combination of at least two thereof. Typical but non-limiting combinations include a combination of methanol and ethanol, a combination of ethylene glycol and isopropanol, a combination of butanol and diethylene glycol, a combination of isopropanol, butanol and glycerol, a combination of methanol, ethylene glycol and isopropanol, a combination of ethanol, ethylene glycol and isopropanol, a combination of ethylene glycol, isopropanol, butanol, diethylene glycol and glycerol, preferably methanol, ethanol or ethylene glycol.

[0020] Preferably, the concentration of yttrium salt in the metal ion salt solution is 0.1mol / L-1.0mol / L, for example, it can be 0.1mol / L, 0.2mol / L, 0.3mol / L, 0.4mol / L, 0.5mol / L, 0.6mol / L, 0.7mol / L, 0.8mol / L, 0.9mol / L or 1.0mol / L, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable, preferably 0.3mol / L-0.6mol / L.

[0021] The present invention further controls the concentration of yttrium salt in the metal ion salt solution to be 0.1 mol / L-1.0 mol / L, controls the reaction temperature to regulate the reaction rate, and adjusts the nucleation process and the subsequent growth process, so that the precursor undergoes nucleation and then growth to form a nearly spherical morphology, maintains good uniformity of size, has a narrow particle size distribution, and has no particle agglomeration. After the precursor is calcined, its nearly spherical morphology remains unchanged. The calcination process controls the inside of the particles to be converted into a garnet phase, and there is basically no agglomeration between the particles, so that the particles maintain the dispersed state of the precursor.

[0022] Preferably, the molar ratio of yttrium salt, aluminum salt and cerium salt in the metal ion salt solution is (3-2.5) mol:5 mol:(0-0.5) mol, for example, it can be 2.99 mol:5 mol:0.01 mol, 2.98 mol:5 mol:0.02 mol, 2.97 mol:5 mol:0.03 mol, 2.96 mol:5 mol:0.04 mol, 2.95 mol:5 mol:0.05 mol, 2.94 mol:5 mol:0.06 mol, 2.90 mol:5 mol:0. :0.1mol, 2.85mol:5mol:0.15mol, 2.8mol:5mol:0.2mol, 2.75mol:5mol:0.25mol, 2.7mol:5mol:0.3mol, 2.65mol:5mol:0.35mol, 2.6mol:5mol:0.4mol, 2.55mol:5mol:0.45mol or 2.5mol:5mol:0.5mol, but not limited to the listed values, other values ​​not listed within the numerical range are equally applicable.

[0023] Preferably, the cerium salt comprises any one of cerous nitrate, ammonium cerous nitrate, cerous sulfate or cerous chloride, or a combination of at least two thereof. Typical but non-limiting combinations include a combination of cerous nitrate and ammonium cerous nitrate, a combination of ammonium cerous nitrate and cerous sulfate, a combination of cerous sulfate and cerous chloride, a combination of cerous nitrate, cerous sulfate and cerous chloride, a combination of ammonium cerous nitrate, cerous sulfate and cerous chloride, a combination of cerous nitrate, ammonium cerous nitrate, cerous sulfate and cerous chloride, and a combination of cerous nitrate, ammonium cerous nitrate, cerous sulfate and cerous chloride, preferably cerous nitrate.

[0024] Preferably, the aluminum salt comprises any one of aluminum nitrate, aluminum sulfate or aluminum chloride or a combination of at least two thereof, and typical but non-limiting combinations include a combination of aluminum nitrate and aluminum sulfate, a combination of aluminum sulfate and aluminum chloride, a combination of aluminum nitrate and aluminum chloride, and a combination of aluminum nitrate, aluminum sulfate and aluminum chloride.

[0025] Preferably, the yttrium salt comprises any one or a combination of two of yttrium nitrate, yttrium sulfate or yttrium chloride, typical but non-limiting combinations include a combination of yttrium nitrate and yttrium sulfate, a combination of yttrium sulfate and yttrium chloride, a combination of yttrium nitrate and yttrium chloride, and a combination of yttrium nitrate, yttrium sulfate and yttrium chloride.

[0026] Preferably, the high molecular polymer includes any one of polyvinyl pyrrolidone, polyethylene glycol, hydroxypropyl cellulose or hydroxypropyl methylcellulose, or a combination of at least two thereof. Typical but non-limiting combinations include a combination of polyvinyl pyrrolidone and polyethylene glycol, a combination of polyethylene glycol and hydroxypropyl cellulose, a combination of hydroxypropyl cellulose and hydroxypropyl methylcellulose, a combination of polyvinyl pyrrolidone, hydroxypropyl cellulose and hydroxypropyl methylcellulose, a combination of polyethylene glycol, hydroxypropyl cellulose and hydroxypropyl methylcellulose, and a combination of polyvinyl pyrrolidone, polyethylene glycol, hydroxypropyl cellulose and hydroxypropyl methylcellulose, preferably polyvinyl pyrrolidone.

[0027] Preferably, the amount of the high molecular polymer added is 1 g / L-100 g / L, based on the total volume of the metal ion salt solution, for example, it can be 1 g / L, 10 g / L, 20 g / L, 30 g / L, 40 g / L, 50 g / L, 60 g / L, 70 g / L, 80 g / L, 90 g / L or 100 g / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0028] Preferably, the temperature of the heating reaction is 120°C-230°C, for example, it can be 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, 210°C, 220°C or 230°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable, preferably 140°C-190°C.

[0029] Preferably, the heating reaction time is 2h-30h, for example, 2h, 6h, 10h, 15h, 20h, 25h or 30h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0030] Preferably, after the reaction, before obtaining the submicron-sized cerium-doped yttrium aluminum garnet powder material, solid-liquid separation, washing and drying are also performed.

[0031] Preferably, the drying temperature is 80°C-110°C, for example, it can be 80°C, 85°C, 90°C, 95°C, 100°C, 105°C or 110°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0032] Preferably, the drying time is 2 h-30 h, for example, 2 h, 6 h, 10 h, 15 h, 20 h, 25 h or 30 h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0033] Preferably, the calcination includes oxidative calcination and reductive calcination.

[0034] Preferably, the atmosphere of the oxidative calcination includes an air atmosphere.

[0035] Preferably, the atmosphere of the reducing calcination includes any one of a hydrogen atmosphere, an ammonia atmosphere or a carbon reducing atmosphere, or a combination of at least two of them.

[0036] Preferably, the calcination temperature is 1000°C-1600°C, for example, it can be 1000°C, 1050°C, 1100°C, 1150°C, 1200°C, 1250°C, 1300°C, 1350°C, 1400°C, 1450°C, 1500°C, 1550°C or 1600°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0037] Preferably, the calcination time is 0.5h-5h, for example, it can be 0.5h, 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, 4h, 4.5h or 5h, but is not limited to the listed values. Other unlisted values ​​within the numerical range are also applicable, preferably 2h-3h.

[0038] Preferably, during the calcination process, the heating rate from room temperature to 600°C is 5°C / min, the heating rate from 600°C to the calcination target temperature is 2°C / min, and the holding time at the calcination temperature is 0.5-5h, preferably 2h.

[0039] As a preferred technical solution of the preparation method of the present invention, the preparation method comprises the following steps:

[0040] Yttrium salt, aluminum salt, cerium salt and ethylene glycol and water in a volume ratio of (0.1-2):1 are mixed in a molar ratio of (3-2.5) mol:5 mol:(0-0.5) mol to obtain a metal ion salt solution with a yttrium salt concentration of 0.1 mol / L-1.0 mol / L;

[0041] Mixing the metal ion salt solution and the high molecular polymer, heating the mixture at 120°C-230°C for reaction for 2h-30h, separating the solid from the liquid and washing the mixture, and drying the mixture at 80°C-110°C for 2h-30h to obtain a precursor powder material;

[0042] The precursor powder material is first calcined in an air atmosphere at 1000° C.-1600° C. for 2h-3h, and then calcined in a reducing atmosphere at 1000° C.-1600° C. for 2h-3h to obtain the submicron-sized cerium-doped yttrium aluminum garnet powder material.

[0043] In a second aspect, the present invention provides a submicron-sized cerium-doped yttrium aluminum garnet powder material prepared by the preparation method described in the first aspect.

[0044] The chemical formula of the submicron-sized cerium-doped yttrium aluminum garnet powder material is: 3-x Ce x Al 5 O 12 , wherein 0<x<0.5, for example, it can be 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45 or 0.5, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0045] The average particle size of the submicron cerium-doped yttrium aluminum garnet powder material is 70nm-1000nm, for example, it can be 70nm, 100nm, 200nm, 300nm, 400nm, 500nm, 600nm, 700nm, 800nm, 900nm or 1000nm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0046] In a third aspect, the present invention provides an application of a submicron cerium-doped yttrium aluminum garnet powder material as described in the second aspect, wherein the submicron cerium-doped yttrium aluminum garnet powder material is used in the field of white light LED or transparent ceramic powder fluorescence luminescence.

[0047] The submicron-sized cerium-doped yttrium aluminum garnet powder material provided by the present invention is used in the fields of fluorescence conversion and white light LEDs, with an excitation spectrum peak at 458nm, which can well match the blue light chip, an emission spectrum peak at 542nm, and an internal quantum efficiency of up to 88.3%.

[0048] The numerical range described in the present invention not only includes the point values ​​listed above, but also includes any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0049] Compared with the prior art, the present invention has at least the following beneficial effects:

[0050] (1) The present invention adopts a hydrothermal alcohol solvent thermal synthesis method, uses a mixed solvent formed by mixing a single alcohol organic solvent with water, and controls the nucleation and growth of a yttrium aluminum garnet precursor to prepare Ce with high sphericity, uniform morphology, narrow particle size distribution, and adjustable size in a wide range. 3+ The doped yttrium aluminum garnet powder precursor powder is calcined at high temperature to obtain a cerium-doped yttrium aluminum garnet powder material with a submicron size, a nearly spherical morphology, a narrow particle size distribution, and a uniform morphology.

[0051] (2) The size of the submicron cerium-doped yttrium aluminum garnet powder material provided by the present invention is adjustable in a wide range from 70 nm to 1000 nm, and the powder most suitable for transparent ceramic sintering can be freely selected.

[0052] (3) The submicron-sized cerium-doped yttrium aluminum garnet powder material provided by the present invention is used in the field of fluorescence conversion and white light LED. The excitation spectrum peak is located at 458nm, which can well match the blue light chip. The emission spectrum peak is located at 542nm, and the internal quantum efficiency can reach 88.3%. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 is a SEM image of the precursor powder material in Example 1 of the present invention;

[0054] Figure 2 The Ce obtained in Example 1 of the present invention 3+ XRD pattern of yttrium aluminum garnet powder material;

[0055] Figure 3 Ce obtained in Example 1 of the present invention 3+ SEM image of yttrium aluminum garnet powder material;

[0056] Figure 4 Ce obtained in Example 1 of the present invention 3+ Excitation spectrum and emission spectrum of yttrium aluminum garnet powder material;

[0057] Figure 5 Ce obtained in Example 4 of the present invention 3+ SEM image of yttrium aluminum garnet powder material;

[0058] Figure 6 Ce obtained in Example 5 of the present invention 3+ SEM image of yttrium aluminum garnet powder material;

[0059] Figure 7 Ce obtained in Example 6 of the present invention 3+ SEM image of yttrium aluminum garnet powder material;

[0060] Figure 8 Ce obtained in Example 7 of the present invention 3+ SEM image of yttrium aluminum garnet powder material;

[0061] Fig. 9 Ce obtained in Example 8 of the present invention 3+ SEM image of yttrium aluminum garnet powder material;

[0062] Fig.10 Ce obtained in Example 9 of the present invention 3+ SEM image of yttrium aluminum garnet powder material;

[0063] Fig.11 Ce obtained in Example 1 of the present invention 3+ Distribution diagram of yttrium aluminum garnet powder material in LED luminescence spectrum. DETAILED DESCRIPTION

[0064] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and through specific implementation methods. However, the following examples are only simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

[0065] In the following examples and comparative examples, unless otherwise specified, all reagents and consumables were purchased from conventional reagent manufacturers in the field; unless otherwise specified, the experimental methods and technical means used were conventional methods and means in the field.

[0066] Example 1

[0067] This embodiment provides a method for preparing a submicron-sized cerium-doped yttrium aluminum garnet powder material, the preparation method comprising the following steps:

[0068] (1) mixing yttrium nitrate, aluminum nitrate, cerium nitrate and ethylene glycol and water in a volume ratio of 1:1 in a molar ratio of 2.95:5:0.05 to obtain a metal ion salt solution with a yttrium nitrate concentration of 0.6 mol / L; mixing the metal ion salt solution with polyvinyl pyrrolidone (K30), the concentration of polyvinyl pyrrolidone is 1 wt%, transferring the reaction solution to a polytetrafluoroethylene reactor, heating the reaction solution at 180° C. for 15 h, separating the solid from the liquid and washing, and drying the mixture at 80° C. for 12 h to obtain a precursor powder material;

[0069] (2) The precursor powder material was first calcined at 1350°C for 2 h in an air atmosphere, cooled naturally to room temperature, and then calcined at 1350°C for 2 h in a hydrogen and nitrogen atmosphere to obtain Ce 3+ Doped YAG powder material.

[0070] Figure 1 This is a scanning electron microscope (SEM) photo of the precursor powder material. The image results show that the powder is composed of approximately spherical particles, and has a monodisperse characteristic and a uniform particle size distribution with an average size of 640nm.

[0071] Figure 2 For Ce 3+X-ray diffraction analysis (XRD) spectrum of the doped YAG powder material shows that the prepared powder is pure garnet phase. The diffraction of the (321) crystal plane, (400) crystal plane, (420) crystal plane and (422) crystal plane of the YAG powder can be clearly presented in the spectrum, and the peak shape is sharp, indicating that the prepared Ce 3+ The doped YAG powder has good crystallinity.

[0072] Figure 3 For Ce 3+ Scanning electron microscope (SEM) photo of doped YAG powder. The image results show that the powder is composed of nearly spherical particles, and has a monodisperse characteristic and uniform particle size distribution. The average size is 580nm. After calcination, its size decreases to a certain extent.

[0073] Figure 4 For Ce 3+ The excitation and emission spectra of doped YAG powder. The results in the picture show that the excitation spectrum peak of the phosphor is at 458nm, which can well match the blue light chip. The emission spectrum peak is at 542nm, and its internal quantum efficiency can reach 88.3%.

[0074] Example 2

[0075] This embodiment provides a method for preparing a submicron-sized cerium-doped yttrium aluminum garnet powder material, the preparation method comprising the following steps:

[0076] (1) mixing yttrium sulfate, aluminum sulfate, cerium sulfate and methanol and water in a volume ratio of 0.5:1 in a molar ratio of 2.99:5:0.01 to obtain a metal ion salt solution with a yttrium sulfate concentration of 0.5 mol / L; mixing the metal ion salt solution with polyvinyl pyrrolidone (K30), the concentration of polyvinyl pyrrolidone is 5 wt%, transferring the reaction solution to a polytetrafluoroethylene reactor, heating the reaction solution at 140° C. for 16 h, separating the solid from the liquid and washing, and drying the mixture at 100° C. for 10 h to obtain a precursor powder material;

[0077] (2) The precursor powder material was first calcined at 1000°C for 3 h in an air atmosphere, cooled naturally to room temperature, and then calcined at 1000°C for 3 h in a hydrogen and nitrogen atmosphere to obtain Ce 3+ Doped YAG powder material.

[0078] Example 3

[0079] This embodiment provides a method for preparing a submicron-sized cerium-doped yttrium aluminum garnet powder material, the preparation method comprising the following steps:

[0080] (1) mixing yttrium nitrate, aluminum chloride, cerium chloride and isopropanol and water in a volume ratio of 1.5:1 in a molar ratio of 2.75:5:0.25 to obtain a metal ion salt solution with a concentration of 0.8 mol / L of yttrium chloride; mixing the metal ion salt solution with polyvinyl pyrrolidone (K30), wherein the concentration of polyvinyl pyrrolidone is 20 wt %, transferring the reaction solution to a polytetrafluoroethylene reactor, heating the reaction solution at 190° C. for 15 h, performing solid-liquid separation and washing, and drying the mixture at 90° C. for 12 h to obtain a precursor powder material;

[0081] (2) The precursor powder material was first calcined at 1500°C for 1.5 h in an air atmosphere, cooled naturally to room temperature, and then calcined at 1500°C for 1.5 h in a hydrogen and nitrogen atmosphere to obtain Ce 3+ Doped YAG powder material.

[0082] Example 4

[0083] The present embodiment provides a method for preparing a submicron-sized cerium-doped yttrium aluminum garnet powder material, which differs from Example 1 only in that, in step (1), yttrium nitrate, aluminum nitrate, cerous nitrate and ethylene glycol and water in a volume ratio of 1:1 are mixed in a molar ratio of 2.95:5:0.05 to obtain a metal ion salt solution with a yttrium salt concentration of 0.1 mol / L.

[0084] Figure 5 The prepared Ce 3+ Scanning electron microscope (SEM) image of doped YAG powder material. The image results show that the powder is composed of approximately spherical particles, and has a monodisperse characteristic and uniform particle size distribution with an average size of 80nm.

[0085] Example 5

[0086] The present embodiment provides a method for preparing a submicron-sized cerium-doped yttrium aluminum garnet powder material, which differs from Embodiment 1 only in that, in step (1), yttrium nitrate, aluminum nitrate, cerous nitrate and ethylene glycol and water in a volume ratio of 1:1 are mixed in a molar ratio of 2.95:5:0.05 to obtain a metal ion salt solution with a yttrium salt concentration of 0.3 mol / L.

[0087] Figure 6 The prepared Ce 3+ Scanning electron microscope (SEM) image of doped YAG powder material. The image results show that the powder is composed of approximately spherical particles, and has a monodisperse characteristic and uniform particle size distribution with an average size of 190nm.

[0088] Example 6

[0089] The present embodiment provides a method for preparing a submicron-sized cerium-doped yttrium aluminum garnet powder material, which differs from Example 1 only in that, in step (1), yttrium nitrate, aluminum nitrate, cerous nitrate and ethylene glycol and water in a volume ratio of 1:1 are mixed in a molar ratio of 2.95:5:0.05 to obtain a metal ion salt solution with a yttrium salt concentration of 0.45 mol / L.

[0090] Figure 7 The prepared Ce 3+ Scanning electron microscope (SEM) image of doped YAG powder material. The image results show that the powder is composed of approximately spherical particles, and has a monodisperse characteristic and uniform particle size distribution with an average size of 270nm.

[0091] Example 7

[0092] The present embodiment provides a method for preparing a submicron-sized cerium-doped yttrium aluminum garnet powder material, which differs from Example 1 only in that, in step (1), yttrium nitrate, aluminum nitrate, cerous nitrate and ethylene glycol and water in a volume ratio of 1:1 are mixed in a molar ratio of 2.95:5:0.05 to obtain a metal ion salt solution with a yttrium salt concentration of 1.2 mol / L.

[0093] Figure 8 The prepared Ce 3+ Scanning electron microscope (SEM) image of doped YAG powder material. The image results show that the powder is composed of nearly spherical particles, and has a monodisperse characteristic and uniform particle size distribution with an average size of 1260nm.

[0094] Example 8

[0095] This embodiment provides a method for preparing a submicron-sized cerium-doped yttrium aluminum garnet powder material, which is different from Embodiment 1 only in that the ethylene glycol in step (1) is replaced by an equal volume of ethanol.

[0096] Fig. 9 The prepared Ce 3+ Scanning electron microscope (SEM) image of doped YAG powder material. The image results show that the powder is composed of approximately spherical particles, and has a monodisperse characteristic and uniform particle size distribution with an average size of 540nm.

[0097] This example shows that ethanol has the same effect as ethylene glycol, and ethanol can replace ethylene glycol.

[0098] Example 9

[0099] This embodiment provides a method for preparing a submicron-sized cerium-doped yttrium aluminum garnet powder material, which is different from Embodiment 1 only in that the heating reaction temperature in step (1) is set to 200°C.

[0100] Fig.10 The prepared Ce 3+ Scanning electron microscope (SEM) image of doped YAG powder material. The image results show that the powder is composed of approximately spherical particles, the particle size distribution is broadened to a certain extent, and some particles are agglomerated with an average size of 600nm.

[0101] This example shows that higher hydrothermal and solvothermal conditions can also prepare better Ce 3+ doped YAG powder, but the higher reaction temperature consumes more energy.

[0102] Example 10

[0103] This embodiment provides a method for preparing a submicron-sized cerium-doped yttrium aluminum garnet powder material, which is different from Embodiment 1 only in that the calcination temperature in step (2) is 900°C.

[0104] The Ce prepared in this example 3+ The doped YAG powder material is composed of approximately spherical particles, and presents monodisperse characteristics, uniform particle size distribution, and an average size of 580nm. However, the luminous intensity of the sample is not as good as that of Example 1, and its luminous intensity is only 65.4% of that of Example 1.

[0105] Embodiment 11

[0106] This embodiment provides a method for preparing a submicron-sized cerium-doped yttrium aluminum garnet powder material, which is different from Embodiment 1 only in that the heating reaction temperature in step (1) is set to 240°C.

[0107] The Ce prepared in this example 3+ The doped YAG powder material is composed of approximately spherical particles, and the particle size distribution of a single particle is extremely uneven, with particle sizes ranging from 100nm to 1.5μm. This indicates that under excessively high temperature conditions, the reaction will have problems of continuous nucleation and growth, and it is impossible to obtain products of uniform size.

[0108] Comparative Example 1

[0109] This comparative example provides a method for preparing a cerium-doped yttrium aluminum garnet powder material, which is different from Example 1 only in that polyvinyl pyrrolidone (K30) polymer is not added in step (1), and the remaining steps remain unchanged.

[0110] The Ce prepared in this comparative example 3+ The doped YAG powder is composed of spherical particles, small particles and agglomerated bulk solids. The size of the spherical particles ranges from hundreds of nanometers to several microns, while the agglomerated bulk solids are particles above the micron level.

[0111] Comparative Example 2

[0112] This comparative example provides a method for preparing a cerium-doped yttrium aluminum garnet powder material, which differs from Example 1 only in that ethylene glycol is replaced with an equal volume of water in step (1), and the remaining steps remain unchanged. After the reaction is completed, no precipitate is generated in the reaction solution, indicating that the precipitation reaction cannot proceed without the addition of alcohol.

[0113] Application Example 1

[0114] The Ce obtained in Example 1 above 3+ The doped YAG powder and blue light chip are packaged into white light LED, and the optical performance of the LED is tested.

[0115] Ce 3+ The doped YAG powder and epoxy resin are mixed evenly in a mass ratio of 1:4, and the mixture is coated on a blue light chip with a main peak of emission spectrum at 450nm, packaged, and then cured at 150℃ for 2h to obtain a white light LED light source with a color rendering index of 87.1. The spectrum of the obtained LED light source is tested using an LED spectrum tester, and its spectral distribution is as follows Fig.11 As shown, it can be seen that the continuity of the spectrum is good.

[0116] In addition, Ce 3+ Doped YAG powder, (Ca, Sr)AlSiN 3 :Eu 2+ The mixture is uniformly mixed with epoxy resin in a mass ratio of 2:1:8, and the mixture is coated on a blue light chip with a main peak of emission spectrum at 450nm, packaged, and then cured at 150℃ for 2h to obtain a white light LED light source with a color rendering index of 87.1. The spectrum of the obtained LED light source is tested using an LED spectrum tester, and its spectral distribution is as follows Fig.11 As shown, it can be seen that the continuity of the spectrum is good.

[0117] Ce prepared in the examples of the present invention and the comparative examples 3+ The particle size distribution of doped YAG powder material is shown in Table 1 below:

[0118] Table 1

[0119]

[0120]

[0121] The test results show that:

[0122] (1) It can be seen from Examples 1 to 8 that the present invention adopts a hydrothermal alcohol solvent thermal synthesis method, uses a mixed solvent formed by mixing a single alcohol organic solvent with water, controls the nucleation and growth of a yttrium aluminum garnet precursor, and obtains a cerium-doped yttrium aluminum garnet powder material having a nearly spherical morphology, a narrow particle size distribution, and a uniform morphology after high-temperature calcination. The size of the cerium-doped yttrium aluminum garnet powder material is adjustable in a wide range from 70 nm to 1000 nm, and the powder most suitable for transparent ceramic sintering can be freely selected.

[0123] (2) By comparing Example 1 with Example 9, it can be seen that when the heating reaction temperature in step (1) is 200°C, higher hydrothermal and solvothermal conditions can also prepare better Ce 3+ doped YAG powder, but the higher reaction temperature consumes more energy; by comparing Example 1 with Example 11, it can be seen that when the heating reaction temperature in step (1) is too high, that is, 240°C, Ce 3+ The doped YAG powder material is composed of approximately spherical particles, and the particle size distribution of a single particle is extremely uneven. The particle size ranges from 100nm to 1.5μm, and it is impossible to obtain a product with uniform size.

[0124] (3) By comparing Example 1 with Example 10, it can be seen that when the calcination temperature is too low, Ce 3+ The luminescence intensity of the doped YAG powder material decreases.

[0125] (4) It can be seen from Example 1 and Comparative Examples 1 and 2 that the present invention achieves the purpose of controlling the nucleation and growth of the yttrium aluminum garnet precursor by adopting a mixed solvent formed by mixing an alcohol organic solvent with water and regulating the reaction rate by regulating the alcohol substance and the reaction temperature, thereby achieving the controllable synthesis of the precursor particles by utilizing the slow growth of nanocrystals.

[0126] In summary, the present invention adopts a hydrothermal alcohol solvent thermal synthesis method, uses a mixed solvent formed by mixing a single alcohol organic solvent with water, controls the nucleation and growth of a yttrium aluminum garnet precursor, and obtains a cerium-doped yttrium aluminum garnet powder material with a nearly spherical morphology, a narrow particle size distribution, and a uniform morphology after high-temperature calcination. The size of the cerium-doped yttrium aluminum garnet powder material is adjustable in a wide range from 70nm to 1000nm, and the powder most suitable for transparent ceramic sintering can be freely selected.

[0127] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing a submicron-sized cerium-doped yttrium aluminum garnet powder material, characterized in that: The preparation method comprises the following steps: Mixing yttrium salt, aluminum salt, cerium salt and solvent to obtain a metal ion salt solution; mixing the metal ion salt solution with a high molecular polymer, and heating the mixture to obtain a precursor powder material; The precursor powder material is calcined to obtain the submicron-sized cerium-doped yttrium aluminum garnet powder material; The mixed solvent includes an alcohol organic solvent and water.

2. The preparation method according to claim 1, characterized in that: The volume ratio of the alcohol organic solvent to water in the mixed solvent is (0.1-2):1; Preferably, the alcohol organic solvent includes any one of methanol, ethanol, ethylene glycol, isopropanol, butanol, diethylene glycol or glycerol, or a combination of at least two thereof; preferably methanol, ethanol or ethylene glycol.

3. The preparation method according to claim 1 or 2, characterized in that: The concentration of yttrium salt in the metal ion salt solution is 0.1 mol / L-1.0 mol / L; Preferably, the molar ratio of yttrium salt, aluminum salt and cerium salt in the metal ion salt solution is (3-2.5) mol:5 mol:(0-0.5) mol.

4. The preparation method according to any one of claims 1 to 3, characterized in that The cerium salt includes any one or a combination of at least two of cerous nitrate, ammonium cerous nitrate, cerous sulfate or cerous chloride; Preferably, the aluminum salt comprises any one or a combination of at least two of aluminum nitrate, aluminum sulfate or aluminum chloride; Preferably, the yttrium salt includes any one of yttrium nitrate, yttrium sulfate or yttrium chloride, or a combination of two thereof.

5. The preparation method according to any one of claims 1 to 4, characterized in that: The high molecular polymer includes any one of polyvinyl pyrrolidone, polyethylene glycol, hydroxypropyl cellulose or hydroxypropyl methyl cellulose or a combination of at least two thereof; Preferably, the amount of the high molecular polymer added is 1 g / L-100 g / L based on the total volume of the metal ion salt solution.

6. The preparation method according to any one of claims 1 to 5, characterized in that: The temperature of the heating reaction is 120°C-230°C, preferably 140°C-190°C; Preferably, the heating reaction time is 2h-30h; Preferably, after the reaction, before obtaining the submicron-sized cerium-doped yttrium aluminum garnet powder material, solid-liquid separation, washing and drying are also included; Preferably, the drying temperature is 80°C-110°C; Preferably, the drying time is 2h-30h.

7. The preparation method according to any one of claims 1 to 6, characterized in that: The calcination includes oxidative calcination and reductive calcination; Preferably, the atmosphere of the oxidative calcination includes an air atmosphere; Preferably, the atmosphere of the reductive calcination includes any one or a combination of at least two of a hydrogen atmosphere, an ammonia atmosphere or a carbon reducing atmosphere; Preferably, the calcination temperature is 1000°C-1600°C; Preferably, the calcination time is 0.5h-5h, preferably 2h-3h.

8. The preparation method according to any one of claims 1 to 7, characterized in that: The preparation method comprises the following steps: Yttrium salt, aluminum salt, cerium salt and ethylene glycol and water in a volume ratio of (0.1-2):1 are mixed in a molar ratio of (3-2.5) mol:5 mol:(0-0.5) mol to obtain a metal ion salt solution with a yttrium salt concentration of 0.1 mol / L-1.0 mol / L; Mixing the metal ion salt solution and the high molecular polymer, heating the mixture at 120°C-230°C for reaction for 2h-30h, separating the solid from the liquid and washing the mixture, and drying the mixture at 80°C-110°C for 2h-30h to obtain a precursor powder material; The precursor powder material is first calcined in an air atmosphere at 1000° C.-1600° C. for 2h-3h, and then calcined in a reducing atmosphere at 1000° C.-1600° C. for 2h-3h to obtain the submicron-sized cerium-doped yttrium aluminum garnet powder material.

9. A submicron-sized cerium-doped yttrium aluminum garnet powder material, characterized in that: The submicron-sized cerium-doped yttrium aluminum garnet powder material is prepared according to the preparation method according to any one of claims 1 to 8; the chemical formula of the submicron-sized cerium-doped yttrium aluminum garnet powder material is: Y 3-x Ce x Al5O 12 , where 0<x<0.5; The average particle size of the submicron-sized cerium-doped yttrium aluminum garnet powder material is 70nm-1000nm.

10. An application of the submicron-sized cerium-doped yttrium aluminum garnet powder material as claimed in claim 9, characterized in that: The submicron-sized cerium-doped yttrium aluminum garnet powder material is used in the field of white light LED or transparent ceramic powder fluorescent luminescence.

Images