High color rendering white LED material doped with rare earth Cs2KYCl6

Abstract

This invention discloses a high color rendering white LED material made of rare-earth-doped Cs2KYCl6, belonging to the field of LED material preparation technology. It addresses the technical problem that the uniformity of white light and the aging resistance of existing LED materials need further improvement. This invention adopts a layered composite structure, in which the light-emitting chip is formed by Eu-modified Cs2KYCl6 and optical liquid silicone rubber, providing stable blue-green emission. The encapsulation layer is composed of porous fluorinated aluminum borosilicate microspheres, red oxychloride niobate powder, and fluorosilicone sealant. The porous microspheres achieve uniform light field scattering, the red powder supplements long-wavelength radiation, and the resin and inorganic components form a stable protective layer. The multi-phase synergistic effect enables the material to have a continuous and balanced white light spectrum, high brightness and color uniformity, and maintain low light color drift and attenuation under various aging conditions.

Description

Technical Field

[0001] This invention relates to the field of LED material preparation technology, specifically to a high color rendering white LED material of rare earth-doped Cs2KYCl6. Background Technology

[0002] The development of white LED materials in terms of white light rendering capability and light color uniformity has evolved from a single luminescent component to the synergistic work of multiple types of luminescent and dimming materials. As application scenarios tend to be high brightness, large area and high reliability, research has gradually introduced halide luminescent materials, oxychloride materials and porous inorganic scattering carriers to improve the white light output quality by constructing a more complete spectral distribution and a more controllable light field propagation path.

[0003] Meanwhile, under long-term use conditions, LEDs need to withstand multiple environmental stresses such as temperature, humidity, salt spray and light irradiation. Therefore, the structural stability of the light-emitting material, the reliability of the interface chemistry and the anti-disturbance ability of the light-emitting center have become important factors affecting the color retention. To meet these needs, related research is constantly optimizing aspects such as spectrum construction, material stability and light field modulation of the encapsulation layer in order to obtain higher white light performance and more outstanding aging resistance.

[0004] However, current white LED material systems and packaging methods still have significant shortcomings in terms of white light quality and long-term stability. On the one hand, most solutions rely on the physical mixing of multiple fluorescent materials to complete the spectrum, but the differences in refractive index, particle size and dispersion behavior of different materials make the light field of the light-emitting surface uneven, which can easily cause regional brightness differences and color shift. Moreover, with the increase of operating temperature and the effect of light, the distribution of these light-emitting particles in the packaging medium may change, further reducing the uniformity of light color. On the other hand, some light-emitting materials are sensitive to environments such as humidity, salt spray and ultraviolet radiation, which can easily lead to structural degradation, ion migration or interface reaction, thereby causing luminous flux decay and chromaticity shift, making it difficult to maintain stable white light output in the long term.

[0005] The aforementioned practical defects indicate that establishing an effective synergistic relationship between the luminescent properties of materials, structural stability, and the light field modulation of the encapsulation layer is a key challenge that has not yet been fully resolved in current white LED technology. To address this, a solution is proposed. Summary of the Invention

[0006] The purpose of this invention is to provide a high color rendering white LED material of rare earth doped Cs2KYCl6, which solves the technical problem that the uniformity of white light and the aging resistance of LED materials in the prior art need to be further improved.

[0007] The objective of this invention can be achieved through the following technical solution: a high color rendering white LED material doped with rare earth Cs2KYCl6, comprising a light-emitting chip and an encapsulation layer covering its surface, wherein the encapsulation layer comprises the following raw materials in parts by weight: 2-3 parts porous fluorine-containing aluminum borosilicate microspheres, 1 part red light barium gadolinium oxychloride niobate powder and 32-40 parts fluorosilicone sealant.

[0008] The light-emitting chip is prepared by the following method:

[0009] A1. After mixing Eu-modified Cs2KYCl6 powder with optical liquid silicone rubber, the mixture is degassed and stirred in a vacuum planetary mixer for 10-20 minutes to obtain a uniform light-emitting chip paste. The ratio of Eu-modified Cs2KYCl6 powder to optical liquid silicone rubber is 1g:2-3g.

[0010] A2. Apply the light-emitting chip paste evenly to a flat mold, controlling the thickness to be 0.4-0.6mm, and cure at 80-120℃ for 1-2 hours to obtain the light-emitting chip board.

[0011] A3. Use a punch press to process the light-emitting chip material into square pieces with a side length of 2-3mm to obtain the light-emitting chip.

[0012] Furthermore, the encapsulation layer is prepared by the following method:

[0013] B1. By weight, porous fluorine-containing aluminum borosilicate microspheres and red light oxychloride niobate barium gadolinium powder are added to a mortar and mixed and ground, and then sieved through a 300-mesh sieve to obtain a binary powder mixture;

[0014] B2. Add the thermoplastic fluorosilicone sealant granules to the extruder, add the binary powder mixture, melt and knead at 120-140℃ for 8-10 minutes, then extrude and coat the surface of the light-emitting chip to obtain the encapsulation layer.

[0015] Furthermore, the Eu-modified Cs2KYCl6 powder is prepared by the following method:

[0016] C1. Cesium chloride, potassium chloride, yttrium chloride, europium chloride, antimony chloride and deionized water are added to the reaction vessel and stirred. After the materials are dissolved, citric acid monohydrate and disodium ethylenediaminetetraacetate are added and mixed evenly. The pH of the reaction system is adjusted to 6-7 with saturated ammonia water and then allowed to stand for aging for 12-16 hours. After post-processing, rare earth-doped chlorine-oxygen powder is obtained.

[0017] C2. Rare earth-doped chlorine oxychloride powder, cesium chloride, potassium chloride and polyethylene glycol are added to a stirring vessel and stirred until uniform. Then, the mixture is sent to a tube furnace at a temperature of 600-640℃ and kept at that temperature for 4-6 hours. The post-treatment yields Eu-modified Cs2KYCl6 powder.

[0018] The principle for preparing Eu-modified Cs2KYCl6 powder is as follows:

[0019] Based on the synergistic complexation and uniform gelation process of multi-metal chloride salts in the solution system, Cs was affected by citrate monohydrate and disodium ethylenediaminetetraacetate. + K + Y3 + Eu3 + Sb3 + Plasma is used to stabilize and complex the components, resulting in uniform dispersion at the molecular scale. Subsequently, under weakly acidic to neutral conditions, the system undergoes slow structural rearrangement and aggregation to obtain a chlorine-oxygen precursor gel with uniform composition and doping, ultimately transforming it into rare-earth-doped chlorine-oxygen powder. Following this, under high-temperature halogenation conditions, the rare-earth-doped chlorine-oxygen powder components are further processed in Cs... + K + Structural reconstruction occurs in the ion migration system, allowing rare earth ions to be uniformly incorporated into the Cs2KYCl6 lattice and forming a stable halide double perovskite phase, ultimately yielding Eu-modified Cs2KYCl6 powder.

[0020] Further, in step C1, the ratio of the amounts of cesium chloride, potassium chloride, yttrium chloride, europium chloride, antimony chloride, deionized water, citric acid monohydrate, and disodium ethylenediaminetetraacetate is 2.4g:1.8-2.4g:1.6-1.8g:0.1-0.2g:0.2-0.3g:200mL:1.8-2.1g:1.8-2.1g. The post-processing includes: collecting the filter cake by vacuum filtration, and transferring the filter cake to a drying oven at 60°C for vacuum drying to constant weight to obtain rare earth-doped chlorine-oxygen powder.

[0021] Further, in step C2, the ratio of rare earth-doped oxychloride powder, cesium chloride, potassium chloride, and polyethylene glycol is 8-10g:1.8-2.0g:1.6-1.8g:0.1-0.2g. The post-processing includes: after heat preservation, waiting for the tube furnace temperature to drop to room temperature, washing the material three times with anhydrous ethanol and deionized water, transferring the material to a drying oven at 60°C for vacuum drying to constant weight, and milling it through a 200-300 mesh sieve to obtain Eu-modified Cs2KYCl6 powder.

[0022] Furthermore, the preparation method of the porous fluorinated aluminum borosilicate microspheres includes the following steps:

[0023] D1. Add tetraethyl orthosilicate, anhydrous ethanol and deionized water to the reaction vessel and stir. After the mixture is evenly dispersed, adjust the pH of the reaction system to 4-5 with acetic acid. Then add aluminum nitrate nonahydrate, boric acid, potassium nitrate and ammonium fluoride. Continue to heat and stir for 40-60 min. After post-treatment, fluorine-containing aluminum borosilicate microspheres are obtained.

[0024] D2. Fluorine-containing aluminum borosilicate microspheres were added to a tube furnace at 750℃ and kept at that temperature for 1.5-2.5 hours. The temperature of the tube furnace was then lowered to 600℃ and kept at that temperature for 2-4 hours. After the heat treatment was completed, the tube furnace was allowed to cool to room temperature. The material was then removed and transferred to a reaction vessel containing a 0.1 mol / L hydrochloric acid aqueous solution. The mixture was allowed to stand at room temperature for 1-2 hours. The resulting porous fluorine-containing aluminum borosilicate microspheres were then obtained.

[0025] The principle for preparing porous fluorinated aluminum borosilicate microspheres is as follows:

[0026] First, in an acidic alcohol sol environment, silanol salts undergo hydrolysis and condensation reactions to construct a silicon-oxygen network. Aluminum, boron, and alkali metal ions participate in the formation of a three-dimensional oxide framework through coordination or intercalation. Under the regulation of fluorine-containing components, precursor microspheres with local structural heterogeneity are established. During the subsequent high-temperature glass transition and medium-temperature crystallization processes, phase separation occurs within the system, generating selectively soluble boron-rich and potassium-rich phase regions. After mild acid treatment, the soluble phase is selectively removed, thereby forming a through-pore structure while maintaining the overall morphology, achieving the porosity of fluorine-containing aluminum borosilicate microspheres. Finally, through the synergistic mechanism of precursor homogeneous polymerization-glass transition-phase separation crystallization and acid etching-induced structural rearrangement in the sol system, porous fluorine-containing aluminum borosilicate microspheres are prepared.

[0027] Further, in step D1, the ratio of tetraethyl orthosilicate, anhydrous ethanol, deionized water, aluminum nitrate nonahydrate, boric acid, potassium nitrate, and ammonium fluoride is 40-60 mL: 200 mL: 80 mL: 4 g: 1.6 g: 1.6 g: 0.4 g. The post-treatment includes: after stirring, the reaction system is transferred to a spray dryer, and spray drying is performed with an inlet temperature of 180-210℃ and an outlet temperature of 90-110℃. The resulting powder is collected to obtain fluorinated aluminum borosilicate microspheres.

[0028] Furthermore, in step D2, the ratio of fluorinated aluminum borosilicate microspheres to 0.1 mol / L hydrochloric acid aqueous solution is 8-12 g: 250 mL. Post-treatment includes: after settling, collecting the filter cake by vacuum filtration, and transferring the filter cake to a drying oven at 60°C for vacuum drying to constant weight, yielding a specific surface area of ​​40-60 m². 2 Porous fluorinated aluminoborosilicate microspheres with a pore size of 40-60 nm, a through-pore ratio of 50-60%, and a pore volume of 0.2-0.3 mL / g.

[0029] Furthermore, the preparation method of the red-light barium gadolinium oxychloride powder is as follows: barium carbonate, gadolinium oxide, niobium pentoxide, barium chloride dihydrate, manganese dioxide and chromium oxide are added to a mortar, deionized water is added and wet-milled to obtain a mixed slurry, and then the mixed slurry is transferred to a tube furnace, and the tube furnace is heated to 1200-1250℃ at 3-5℃ / min and held for 6-8h. After post-treatment, the red-light barium gadolinium oxychloride powder is obtained.

[0030] The principle for preparing red-light-emitting barium gadolinium oxychloride niobate powder is as follows:

[0031] Based on the solid-phase ion diffusion-driven composite oxychloride niobate crystal phase construction mechanism, under high temperature conditions, metal oxides such as Ba, Gd, and Nb and chlorides undergo mutual solid-state reactions to form a stable oxychloride niobate framework. Trace transition metal components introduce luminescent active centers into the crystal lattice, thereby endowing the material with characteristic red light emission behavior, and finally preparing red light barium gadolinium oxychloride niobate powder.

[0032] Furthermore, in the preparation of red-light barium gadolinium oxychloride powder, the ratio of barium carbonate, gadolinium oxide, niobium pentoxide, barium chloride dihydrate, manganese dioxide, chromium oxide, and deionized water is 4.0-4.2g:2g:3.0-3.2g:1.6-1.8g:0.01-0.02g:0.01-0.02g:8-10mL. The post-treatment includes: allowing the tube furnace to cool naturally to room temperature, and grinding through a 200-300 mesh sieve to obtain red-light barium gadolinium oxychloride powder.

[0033] The present invention has the following beneficial effects:

[0034] 1. This invention uses Eu-modified Cs2KYCl6 as the main light-emitting material of the light-emitting chip. Its double perovskite lattice forms a stable octahedral framework under high-temperature halide reconstruction conditions, enabling Eu... 3+ The doping centers are uniformly embedded in the lattice and maintain the characteristic blue-green emission energy level structure; the optical liquid silicone rubber matrix achieves uniform dispersion and fixed position of powder particles, making the spatial distribution of the light-emitting chip stable during the molding, curing and lighting process, and is not prone to light spots and particle migration. Since the light-emitting chip layer contains only one light-emitting material, its spectral composition is simple and highly repeatable, which can provide a predictable and superimposed blue-green emission basis for the supplementary light layer, while avoiding the refractive index difference and light field distortion caused by the mixing of multiple materials, thus making the entire white light construction process more controllable and spectrally stable.

[0035] 2. The porous fluorinated aluminum borosilicate microspheres in the encapsulation layer prepared by this invention have through-holes and multi-scale microporous structures. Incident light undergoes multiple scatterings within them and tends to become random, allowing the blue and green light from the light-emitting chip to undergo lateral diffusion and smoothing before emission, thereby significantly improving the brightness uniformity of the light-emitting surface. At the same time, the red oxychloride niobate powder is uniformly distributed within the encapsulation layer, and its long-wavelength emission can form a continuous spectrum together with the blue and green light from the light-emitting chip, enabling the white light to obtain the necessary energy compensation in the short-wavelength to long-wavelength range, effectively avoiding the risk of spectral dip and color deviation. Since the scattering network and red light compensation belong to different functional units and are physically isolated from the light-emitting core layer, the three form a light field structure that does not interfere with each other but works together, significantly reducing the spectral differences of the device at different viewing angles, and ultimately achieving high color rendering, high color uniformity and stable white light output.

[0036] 3. The red oxychloride niobate material prepared by this invention has a stable Nb-O-Cl lattice structure, exhibiting excellent structural inertness under humid heat and light irradiation conditions, which can provide support for long-term luminescence stability. The fluorosilicone sealant, as the encapsulation layer substrate, has high chemical bond energy, low water absorption, and excellent UV resistance, and can form a dense hydrophobic protective layer outside the light-emitting chip. The silicon-oxygen inorganic framework inside the porous fluorinated aluminum borosilicate microspheres maintains structural integrity in the salt spray environment and has a natural barrier effect against water vapor and corrosive ions. The three work together to form a multi-layered stable barrier, making it difficult for external humid heat, salt spray, and light stress to directly act on the light-emitting chip layer, inhibiting degradation pathways including anion migration, interface decomposition, and colloidal aging. Therefore, the white LED material prepared by this invention exhibits low chromaticity drift, low brightness decay, and high color retention rate under long-term use and comprehensive aging conditions. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1 The image shows the XRD pattern of the red-light barium gadolinium oxychloride powder prepared in Example 9 of this invention. Detailed Implementation

[0039] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] In this application, the polyethylene glycol used was purchased from Shanghai Maclean Biochemical Technology Co., Ltd., with the product number P815611; the optical liquid silicone rubber used was purchased from Anhui Mingyi Silicon Industry Co., Ltd., with the product number MY 3G30MY; and the fluorosilicone sealant used was purchased from Anhui Mingyi Silicon Industry Co., Ltd., with the product number FLSR-3140.

[0041] Example 1

[0042] This embodiment provides a method for preparing Eu-modified Cs2KYCl6 powder, including the following steps:

[0043] Step I: Preparation of rare earth-doped oxychloride powder

[0044] Weigh out 2.4g of cesium chloride, 1.8g of potassium chloride, 1.6g of yttrium chloride, 0.1g of europium chloride, 0.2g of antimony chloride, and 200.0mL of deionized water and add them to the reaction vessel. Stir until the materials dissolve. Then add 1.8g of citric acid monohydrate and 1.8g of disodium ethylenediaminetetraacetate. Mix well and adjust the pH of the reaction system to 6 with saturated ammonia water. Let it stand for aging for 12 hours. Collect the filter cake by vacuum filtration and transfer it to a drying oven at 60℃. Vacuum dry to constant weight to obtain rare earth doped chlorine-oxygen powder.

[0045] Step II: Preparation of Eu-modified Cs2KYCl6 powder

[0046] Weigh out 8.0g of rare earth-doped chlorine-oxygen powder, 1.8g of cesium chloride, 1.6g of potassium chloride, and 0.1g of polyethylene glycol and add them to a mixing vessel. After mixing evenly, place the mixture into a tube furnace at 600℃ and keep it at that temperature for 4 hours. After the temperature of the tube furnace is reduced to room temperature, wash the material three times with anhydrous ethanol and deionized water. Then transfer the material to a drying oven at 60℃ and vacuum dry it to constant weight. Finally, grind it through a 200-mesh sieve to obtain Eu-modified Cs2KYCl6 powder.

[0047] Example 2

[0048] This embodiment provides a method for preparing Eu-modified Cs2KYCl6 powder, including the following steps:

[0049] Step I: Preparation of rare earth-doped oxychloride powder

[0050] Weigh out 2.4g of cesium chloride, 2.4g of potassium chloride, 1.8g of yttrium chloride, 0.2g of europium chloride, 0.3g of antimony chloride, and 200.0mL of deionized water and add them to the reaction vessel. Stir until the materials dissolve. Then add 2.1g of citric acid monohydrate and 2.1g of disodium ethylenediaminetetraacetate. Mix well and adjust the pH of the reaction system to 7 with saturated ammonia water. Let it stand for aging for 16 hours. Filter the mixture and collect the filter cake. Transfer the filter cake to a drying oven at 60℃ and vacuum dry it to constant weight to obtain rare earth-doped chlorine-oxygen powder.

[0051] Step II: Preparation of Eu-modified Cs2KYCl6 powder

[0052] Weigh out 10.0g of rare earth-doped chlorine-oxygen powder, 2.0g of cesium chloride, 1.8g of potassium chloride, and 0.2g of polyethylene glycol and add them to a mixing vessel. After mixing evenly, place the mixture into a tube furnace at 640℃ and keep it at that temperature for 6 hours. After the temperature of the tube furnace is reduced to room temperature, wash the material three times with anhydrous ethanol and deionized water. Then transfer the material to a drying oven at 60℃ and vacuum dry it to constant weight. Finally, grind it through a 300-mesh sieve to obtain Eu-modified Cs2KYCl6 powder.

[0053] Example 3

[0054] This embodiment provides a method for preparing Eu-modified Cs2KYCl6 powder, including the following steps:

[0055] Step I: Preparation of rare earth-doped oxychloride powder

[0056] Weigh out 2.4g of cesium chloride, 2.1g of potassium chloride, 1.8g of yttrium chloride, 0.2g of europium chloride, 0.3g of antimony chloride, and 200.0mL of deionized water and add them to the reaction vessel. Stir until the materials dissolve, then add 2.0g of citric acid monohydrate and 2.0g of disodium ethylenediaminetetraacetate. Mix well and adjust the pH of the reaction system to 6 with saturated ammonia water. Let it stand for aging for 14 hours, then filter and collect the filter cake. Transfer the filter cake to a drying oven at 60℃ and vacuum dry it to constant weight to obtain rare earth-doped chlorine-oxygen powder.

[0057] Step II: Preparation of Eu-modified Cs2KYCl6 powder

[0058] Weigh out 9.0g of rare earth-doped chlorine-oxygen powder, 1.9g of cesium chloride, 1.8g of potassium chloride, and 0.2g of polyethylene glycol and add them to a mixing vessel. After mixing evenly, place the mixture into a tube furnace at 620℃ and keep it at that temperature for 5 hours. After the heat treatment is completed, wait for the temperature of the tube furnace to drop to room temperature. Wash the material three times with anhydrous ethanol and deionized water. Then, transfer the material to a drying oven at 60℃ and vacuum dry it to constant weight. Grind it through a 250-mesh sieve to obtain Eu-modified Cs2KYCl6 powder.

[0059] Example 4

[0060] This embodiment provides a method for preparing porous fluorinated aluminum borosilicate microspheres, comprising the following steps:

[0061] Step (1): Preparation of fluorinated aluminum borosilicate microspheres

[0062] Weigh out 40.0 mL of tetraethyl orthosilicate, 200.0 mL of anhydrous ethanol and 80.0 mL of deionized water and add them to the reaction vessel. Stir until the mixture is evenly dispersed. Adjust the pH of the reaction system to 4 with acetic acid. Then add 4.0 g of aluminum nitrate nonahydrate, 1.6 g of boric acid, 1.6 g of potassium nitrate and 0.4 g of ammonium fluoride. Continue stirring at this temperature for 40 min. After stirring is complete, transfer the reaction system to a spray dryer and set the inlet temperature to 180 °C and the outlet temperature to 90 °C for spray drying. Collect the resulting powder to obtain fluorinated aluminum borosilicate microspheres.

[0063] Step 2: Preparation of porous fluorinated aluminum borosilicate microspheres

[0064] Weigh 8.0 g of fluorinated aluminum borosilicate microspheres and add them to a tube furnace at 750 °C. After holding at this temperature for 1.5 h, cool the furnace to 600 °C and hold for 2 h. After the holding period, allow the furnace to cool to room temperature, remove the material, and transfer it to a reaction vessel containing 250.0 mL of 0.1 mol / L hydrochloric acid aqueous solution. Let it stand at room temperature for 1 h. After standing, collect the filter cake by vacuum filtration and transfer it to a drying oven at 60 °C to vacuum dry to constant weight, yielding a specific surface area of ​​51 m². 2 Porous fluorinated aluminum borosilicate microspheres with a pore size of 53 nm, a through-pore ratio of 54%, and a pore volume of 0.3 mL / g.

[0065] Example 5

[0066] This embodiment provides a method for preparing porous fluorinated aluminum borosilicate microspheres, comprising the following steps:

[0067] Step (1): Preparation of fluorinated aluminum borosilicate microspheres

[0068] Weigh out 60.0 mL of tetraethyl orthosilicate, 200.0 mL of anhydrous ethanol and 80.0 mL of deionized water and add them to the reaction vessel. Stir until the mixture is evenly dispersed. Adjust the pH of the reaction system to 5 with acetic acid. Then add 4.0 g of aluminum nitrate nonahydrate, 1.6 g of boric acid, 1.6 g of potassium nitrate and 0.4 g of ammonium fluoride. Continue stirring at this temperature for 60 min. After stirring is complete, transfer the reaction system to a spray dryer. Set the inlet temperature to 210 °C and the outlet temperature to 110 °C for spray drying. Collect the resulting powder to obtain fluorinated aluminum borosilicate microspheres.

[0069] Step 2: Preparation of porous fluorinated aluminum borosilicate microspheres

[0070] Weigh 12.0 g of fluorinated aluminum borosilicate microspheres and add them to a tube furnace at 750 °C. After holding at this temperature for 2.5 h, cool the furnace to 600 °C and hold for 4 h. After the holding period, allow the furnace to cool to room temperature, remove the material, and transfer it to a reaction vessel containing 250.0 mL of 0.1 mol / L hydrochloric acid aqueous solution. Let it stand at room temperature for 2 h. After standing, filter the filter cake and transfer it to a drying oven at 60 °C to vacuum dry to constant weight, yielding a specific surface area of ​​58 m². 2 Porous fluorinated aluminum borosilicate microspheres with a pore size of 55 nm, a through-pore ratio of 57%, and a pore volume of 0.3 mL / g.

[0071] Example 6

[0072] This embodiment provides a method for preparing porous fluorinated aluminum borosilicate microspheres, comprising the following steps:

[0073] Step (1): Preparation of fluorinated aluminum borosilicate microspheres

[0074] Weigh out 50.0 mL of tetraethyl orthosilicate, 200.0 mL of anhydrous ethanol and 80.0 mL of deionized water and add them to the reaction vessel. Stir until the mixture is evenly dispersed. Adjust the pH of the reaction system to 4 with acetic acid. Then add 4.0 g of aluminum nitrate nonahydrate, 1.6 g of boric acid, 1.6 g of potassium nitrate and 0.4 g of ammonium fluoride. Continue stirring for 50 min. After stirring is complete, transfer the reaction system to a spray dryer and set the inlet temperature to 200 °C and the outlet temperature to 100 °C for spray drying. Collect the powder to obtain fluorinated aluminum borosilicate microspheres.

[0075] Step 2: Preparation of porous fluorinated aluminum borosilicate microspheres

[0076] Weigh 10.0 g of fluorinated aluminum borosilicate microspheres and add them to a tube furnace at 750 °C. After holding at this temperature for 2 hours, cool the furnace to 600 °C and hold for 3 hours. After the holding period, allow the furnace to cool to room temperature, remove the material, and transfer it to a reaction vessel containing 250.0 mL of 0.1 mol / L hydrochloric acid aqueous solution. Let it stand at room temperature for 2 hours. After standing, filter the filter cake and transfer it to a drying oven at 60 °C to vacuum dry to constant weight, yielding a specific surface area of ​​42 m². 2 Porous fluorinated aluminum borosilicate microspheres with a pore size of 45 nm, a through-pore ratio of 52%, and a pore volume of 0.2 mL / g.

[0077] Example 7

[0078] This embodiment provides a method for preparing a high color rendering white LED material doped with rare earth Cs2KYCl6, including the following steps:

[0079] Step 1: Preparation of red-light-emitting barium gadolinium oxychloride powder

[0080] Weigh out 4.0g barium carbonate, 2.0g gadolinium oxide, 3.0g niobium pentoxide, 1.6g barium chloride dihydrate, 0.01g manganese dioxide, and 0.01g chromium oxide and add them to a mortar. Add 8.0mL of deionized water and wet grind to obtain a mixed slurry. Then transfer the mixed slurry to a tube furnace and heat it to 1200℃ at 3℃ / min. After holding it at that temperature for 6 hours, allow the tube furnace to cool naturally to room temperature and grind it through a 200-mesh sieve to obtain red-light barium gadolinium oxychloride powder.

[0081] Step 2: Fabrication of the light-emitting chip

[0082] 10.0g of Eu-modified Cs2KYCl6 powder prepared in Example 1 was mixed with 20.0g of optical liquid silicone rubber and then degassed and stirred in a vacuum planetary mixer for 10 minutes to obtain a uniform light-emitting chip slurry.

[0083] The light-emitting chip paste is evenly coated onto a flat mold, with a thickness controlled at 0.4 mm, and cured at 80℃ for 1 hour to obtain the light-emitting chip board.

[0084] The light-emitting chip is obtained by using a punch press to process the light-emitting chip material into a square piece with a side length of 2mm.

[0085] Step 3: Preparation of high color rendering white LED materials

[0086] By weight, 2 parts of the porous fluorinated aluminum borosilicate microspheres prepared in Example 4 and 1 part of red light oxychloride niobate barium gadolinium powder were weighed and added to a mortar for mixing and grinding. The mixture was then sieved through a 300-mesh sieve to obtain a binary powder mixture. The binary powder mixture and 32 parts of fluorosilicone sealant were then added to an extruder and melt-mixed at 120°C for 8 minutes before being extruded and coated onto the surface of the light-emitting chip to obtain an encapsulation layer, thereby preparing a high color rendering white LED material.

[0087] Example 8

[0088] This embodiment provides a method for preparing a high color rendering white LED material doped with rare earth Cs2KYCl6, including the following steps:

[0089] Step 1: Preparation of red-light-emitting barium gadolinium oxychloride powder

[0090] Weigh out 4.2g of barium carbonate, 2.0g of gadolinium oxide, 3.2g of niobium pentoxide, 1.8g of barium chloride dihydrate, 0.02g of manganese dioxide, and 0.02g of chromium oxide, add them to a mortar, add 10.0mL of deionized water and wet grind to obtain a mixed slurry. Then transfer the mixed slurry to a tube furnace, heat the tube furnace to 1250℃ at 5℃ / min, and hold for 8 hours. After the tube furnace cools naturally to room temperature, grind it through a 300-mesh sieve to obtain red-light barium gadolinium oxychloride powder.

[0091] Step 2: Fabrication of the light-emitting chip

[0092] After mixing 10.0g of Eu-modified Cs2KYCl6 powder prepared in Example 2 with 30.0g of optical liquid silicone rubber, the mixture was degassed and stirred in a vacuum planetary mixer for 20 minutes to obtain a uniform light-emitting chip slurry.

[0093] The light-emitting chip paste is evenly coated onto a flat mold, with a thickness controlled at 0.6 mm, and cured at 120℃ for 2 hours to obtain the light-emitting chip board.

[0094] The light-emitting chip is obtained by using a punch press to process the light-emitting chip material into a square piece with a side length of 3mm.

[0095] Step 3: Preparation of high color rendering white LED materials

[0096] By weight, 3 parts of the porous fluorinated aluminum borosilicate microspheres prepared in Example 5 and 1 part of red light oxychloride niobate barium gadolinium powder were weighed and added to a mortar for mixing and grinding. The mixture was then sieved through a 300-mesh sieve to obtain a binary powder mixture. The binary powder mixture and 40 parts of fluorosilicone sealant were then added to an extruder and melt-mixed at 140°C for 10 minutes before being extruded and coated onto the surface of the light-emitting chip to obtain an encapsulation layer, thereby preparing a high color rendering white LED material.

[0097] Example 9

[0098] This embodiment provides a method for preparing a high color rendering white LED material doped with rare earth Cs2KYCl6, including the following steps:

[0099] Step 1: Preparation of red-light-emitting barium gadolinium oxychloride powder

[0100] Weigh out 4.2g of barium carbonate, 2.0g of gadolinium oxide, 3.0g of niobium pentoxide, 1.6g of barium chloride dihydrate, 0.02g of manganese dioxide, and 0.02g of chromium oxide, add them to a mortar, add 9.0mL of deionized water and wet grind to obtain a mixed slurry. Then transfer the mixed slurry to a tube furnace, heat the tube furnace to 1250℃ at 4℃ / min, hold for 7h, and allow the tube furnace to cool naturally to room temperature. Grind the powder through a 250-mesh sieve to obtain red-light barium gadolinium oxychloride powder.

[0101] Figure 1 The XRD test results show that the XRD pattern of the sample exhibits a series of well-distributed diffraction peaks in the range of 2θ = 20°-80°. The main diffraction features are located at approximately 2θ = 27°, 33°, 40°, 45°, 49°, 53°, 58°, 62°, 67°, 71° and 75°, which can be attributed to the (103), (101), (002), (102), (102), (110), (112), (200), (202), (211) and (222) crystal planes, respectively. Each main peak has a sharp shape and a small half-width at half-maximum. The overall baseline is stable, indicating that the sample has good crystallinity and high lattice order. The intensity ratio between each main peak is consistent with the typical diffraction characteristics of the composite oxychloride niobate structure, indicating that the stable lattice unit composed of Ba, Gd, Nb and O / Cl has been successfully established under high-temperature reaction conditions.

[0102] No diffraction peaks related to raw materials such as BaCO3, Gd2O3, Nb2O5, and BaCl2·2H2O were observed across the entire spectrum, nor were any other possible impurity phase characteristic peaks. The single-phase peak array and its completeness shown in the diffraction data indicate that the solid-phase reaction has proceeded sufficiently, and the final product is dominated by a single composite oxochloroniobate phase. Based on the systematic distribution of diffraction peak positions, the completeness of peak shapes, and the absence of impurity peaks in the spectrum, it can be confirmed that the sample has constructed the target crystalline framework composed of Ba-Gd-Nb-O-Cl. This result provides direct and sufficient structural characterization evidence for the material structure and its subsequent optical behavior.

[0103] Step 2: Fabrication of the light-emitting chip

[0104] After mixing 10.0g of Eu-modified Cs2KYCl6 powder prepared in Example 3 with 25.0g of optical liquid silicone rubber, the mixture was degassed and stirred in a vacuum planetary mixer for 15 minutes to obtain a uniform light-emitting chip slurry.

[0105] The light-emitting chip paste is evenly coated onto a flat mold, with a thickness controlled at 0.5 mm, and cured at 100℃ for 2 hours to obtain the light-emitting chip board.

[0106] The light-emitting chip is obtained by using a punch press to process the light-emitting chip material into a square piece with a side length of 2mm.

[0107] Step 3: Preparation of high color rendering white LED materials

[0108] By weight, 3 parts of the porous fluorinated aluminum borosilicate microspheres prepared in Example 6 and 1 part of red light oxychloride niobate barium gadolinium powder were weighed and added to a mortar for mixing and grinding. The mixture was then sieved through a 300-mesh sieve to obtain a binary powder mixture. The binary powder mixture and 36 parts of fluorosilicone sealant were then added to an extruder. After adding the binary powder mixture, the mixture was melt-mixed at 130°C for 9 minutes and then extruded to coat the surface of the light-emitting chip, thus obtaining an encapsulation layer and preparing a high color rendering white LED material.

[0109] Comparative Example 1

[0110] The difference between this comparative example and Example 9 is that step II of the preparation process of the Eu-modified Cs2KYCl6 powder used in step II was omitted.

[0111] Comparative Example 2

[0112] The difference between this comparative example and Example 9 is that step (2) is omitted in the preparation process of the porous fluorinated aluminum borosilicate microspheres used in step two.

[0113] Comparative Example 3

[0114] The difference between this comparative example and Example 9 is that the use of red light barium gadolinium oxychloride niobate powder is omitted in step two.

[0115] Performance testing:

[0116] The chromaticity coordinates (u',v') and color uniformity ∆u',v' of the high color rendering white LED materials prepared in Examples 7-9 and Comparative Examples 1-3 were tested in accordance with the standard GB / T 7922-2023 "Methods for measuring the color of lighting sources".

[0117] Referring to standard GB / T 2423.65-2024 "Environmental Testing Part 2: Test Methods: Salt Spray / Temperature / Humidity / Solar Radiation Comprehensive Test", the chromaticity coordinates a(u',v') and color uniformity a∆ of the high color rendering white LED materials prepared in Examples 7-9 and Comparative Examples 1-3 after aging were compared. u',v' The test was conducted, and the specific data is shown in Table 1.

[0118] Table 1 - Performance Test Data for Each Sample

[0119]

[0120] Data Analysis:

[0121] Comparative analysis of the data in Table 1 reveals that the chromaticity coordinates of the high color rendering white LED lamp prepared using the high color rendering white LED material obtained by this invention are (0.197, 0.476), and the color uniformity ∆... u',v'The chromaticity is 0.03. Furthermore, after comprehensive aging under salt spray, temperature, humidity, and solar radiation conditions, the chromaticity coordinates of this high color rendering white LED lamp are (0.200, 0.480), and the color uniformity a∆ is... u',v' The value is 0.05, and all data points are better than the comparative example. This indicates that:

[0122] In Comparative Example 1, after omitting the high-temperature halogenation reconstruction step of the Eu-modified Cs2KYCl6 powder, the material remained only a rare-earth-doped oxychloride precursor, and Cs2KYCl6 was not established internally. + / K + / Y 3+ / Eu 3+ The dual perovskite structure, under the combined effect, has incomplete lattice energy levels and local coordination environment, and the luminescent center lacks stable energy bands and crystal field constraints. In the light-emitting chip layer, such precursors are difficult to output high-quality blue-green emission, and the emission peak position drifts significantly with changes in external temperature, current, and aging stress. At the same time, the presence of many unsaturated bond sites and random coordination in its lattice greatly increases the number of non-radiative channels, resulting in reduced brightness output, spectral line broadening, and poor spectral repeatability between different batches. After aging with damp heat and salt spray, the precursor structure is more prone to local rearrangement and partial oxychloride bond breakage, manifested as a significant shift in chromaticity coordinates and a faster decay in color rendering than the materials in the examples. This indicates that the stable formation of the dual perovskite phase is the key to ensuring the quality of blue-green emission and long-term light color stability.

[0123] In Comparative Example 2, after omitting the high-temperature-acid etching combined porousization step of the porous fluorinated aluminum borosilicate microspheres, the resulting microspheres maintained a dense, solid structure, lacking interconnected channels and multi-scale micropores. Due to the significant reduction in scattering cross-section, the light propagation path inside the encapsulation layer tended to be linearized. The blue-green light from the light-emitting chip and the red light from the encapsulation layer could not diffuse sufficiently laterally, easily leading to brightness and color differences in local areas. At the lateral observation angle, the spectral composition changed more drastically, causing ∆ u',v' The effect is significantly increased. In addition, the dense microspheres cannot play a role in "dispersing and redistributing" the local bright areas. Small thickness changes or uneven powder distribution in the chip layer are amplified, resulting in uneven color distribution on the light-emitting surface of the device. This result shows that the multi-scale scattering network formed by porous microspheres is an important basis for achieving a high uniformity light field.

[0124] In Comparative Example 3, after the removal of the red-emitting barium gadolinium oxychloride niobate powder, the encapsulation system degenerated into a two-phase system with blue-green emitting and scattering structures. Long-wavelength emission was completely absent, and the emitted spectrum was severely biased towards the short-wavelength region. At initial illumination, the spectral energy was concentrated in the blue-green region, resulting in a significant increase in color temperature and a decrease in color rendering index. During long-term humid heat and light irradiation aging, since the energy was mainly borne by the single emitting center of Eu-Cs2KYCl6, it was unable to share the carrier recombination and local heating through the red light channel, leading to more concentrated attenuation, a significantly increased amplitude of spectral shape change over time, and a continuous blue shift trend in chromaticity coordinates. These results indicate that red-emitting powder plays an irreplaceable role in long-wavelength compensation, energy dispersion, and enhanced aging stability.

[0125] In conclusion, this invention achieves a continuous structural-optical coupling mechanism in terms of spectral construction, light field modulation, and long-term environmental stability through the synergistic effect of Eu-modified Cs2KYCl6 light-emitting chip layer, porous fluorinated aluminum borosilicate microsphere scattering structure, and red-light oxychloride niobate barium gadolinium powder. Eu-modified Cs2KYCl6 provides a stable blue-green emission basis, porous fluorinated microspheres construct a multi-scale random scattering network to balance spatial brightness and angular color difference, and red-light oxychloride niobate supplements radiation in the long-wavelength band and enhances the overall anti-attenuation ability during aging through its lattice stability. The coupling behavior of these three components during processing, molding, and lighting mutually balances each other, keeping the spectral ratio, emission distribution, and color evolution after aging within a controlled range, thereby obtaining a white LED output effect with high color rendering, high color uniformity, and long-term light color stability.

[0126] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to specific implementations. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A high color rendering white LED material doped with rare earth element Cs₂KYCl₆, characterized in that, It comprises a light-emitting chip and an encapsulation layer covering its surface, wherein the encapsulation layer comprises the following raw materials in parts by weight: 2-3 parts porous fluorinated aluminum borosilicate microspheres, 1 part red light oxychloride niobate gadolinium powder and 32-40 parts fluorosilicone sealant. The light-emitting chip is prepared by the following method: A1. After mixing Eu-modified Cs2KYCl6 powder with optical liquid silicone rubber, the mixture is degassed and stirred in a vacuum planetary mixer for 10-20 minutes to obtain a uniform light-emitting chip paste. The ratio of Eu-modified Cs2KYCl6 powder to optical liquid silicone rubber is 1g:2-3g. A2. Apply the light-emitting chip paste evenly to a flat mold, controlling the thickness to be 0.4-0.6mm, and cure at 80-120℃ for 1-2 hours to obtain the light-emitting chip board. A3. Use a punch press to process the light-emitting chip material into square pieces with a side length of 2-3mm to obtain the light-emitting chip.

2. The high color rendering white LED material of rare earth doped Cs₂KYCl₆ according to claim 1, characterized in that, The encapsulation layer is prepared by the following method: B1. By weight, porous fluorine-containing aluminum borosilicate microspheres and red light oxychloride niobate barium gadolinium powder are added to a mortar and mixed and ground, and then sieved through a 300-mesh sieve to obtain a binary powder mixture; B2. Add the thermoplastic fluorosilicone sealant granules to the extruder, add the binary powder mixture, melt and knead at 120-140℃ for 8-10 minutes, then extrude and coat the surface of the light-emitting chip to obtain the encapsulation layer.

3. The high color rendering white LED material of rare earth doped Cs₂KYCl₆ according to claim 1, characterized in that, The Eu-modified Cs2KYCl6 powder was prepared by the following method: C1. Cesium chloride, potassium chloride, yttrium chloride, europium chloride, antimony chloride and deionized water are added to the reaction vessel and stirred. After the materials are dissolved, citric acid monohydrate and disodium ethylenediaminetetraacetate are added and mixed evenly. The pH of the reaction system is adjusted to 6-7 with saturated ammonia water and then allowed to stand for aging for 12-16 hours. After post-processing, rare earth-doped chlorine-oxygen powder is obtained. C2. Rare earth-doped chlorine oxychloride powder, cesium chloride, potassium chloride and polyethylene glycol are added to a stirring vessel and stirred until uniform. Then, the mixture is sent to a tube furnace at a temperature of 600-640℃ and kept at that temperature for 4-6 hours. The post-treatment yields Eu-modified Cs2KYCl6 powder.

4. The high color rendering white LED material of rare earth doped Cs₂KYCl₆ according to claim 3, characterized in that, In step C1, the ratio of the amounts of cesium chloride, potassium chloride, yttrium chloride, europium chloride, antimony chloride, deionized water, citric acid monohydrate, and disodium ethylenediaminetetraacetate is 2.4g:1.8-2.4g:1.6-1.8g:0.1-0.2g:0.2-0.3g:200mL:1.8-2.1g:1.8-2.1g; in step C2, the ratio of the amounts of rare earth-doped chlorine-oxygen powder, cesium chloride, potassium chloride, and polyethylene glycol is 8-10g:1.8-2.0g:1.6-1.8g:0.1-0.2g.

5. The high color rendering white LED material of rare earth doped Cs₂KYCl₆ according to claim 1, characterized in that, The method for preparing the porous fluorinated aluminum borosilicate microspheres includes the following steps: D1. Add tetraethyl orthosilicate, anhydrous ethanol and deionized water to the reaction vessel and stir. After the mixture is evenly dispersed, adjust the pH of the reaction system to 4-5 with acetic acid. Then add aluminum nitrate nonahydrate, boric acid, potassium nitrate and ammonium fluoride. Continue to heat and stir for 40-60 min. After post-treatment, fluorine-containing aluminum borosilicate microspheres are obtained. D2. Fluorine-containing aluminum borosilicate microspheres were added to a tube furnace at 750℃ and kept at that temperature for 1.5-2.5 hours. The temperature of the tube furnace was then lowered to 600℃ and kept at that temperature for 2-4 hours. After the heat treatment was completed, the tube furnace was allowed to cool to room temperature. The material was then removed and transferred to a reaction vessel containing a 0.1 mol / L hydrochloric acid aqueous solution. The mixture was allowed to stand at room temperature for 1-2 hours. The resulting porous fluorine-containing aluminum borosilicate microspheres were then obtained.

6. The high color rendering white LED material of rare earth doped Cs₂KYCl₆ according to claim 5, characterized in that, In step D1, the ratio of tetraethyl orthosilicate, anhydrous ethanol, deionized water, aluminum nitrate nonahydrate, boric acid, potassium nitrate, and ammonium fluoride is 40-60 mL: 200 mL: 80 mL: 4 g: 1.6 g: 1.6 g: 0.4 g; in step D2, the ratio of fluorinated aluminum borosilicate microspheres to 0.1 mol / L hydrochloric acid aqueous solution is 8-12 g: 250 mL.

7. The high color rendering white LED material of rare earth doped Cs₂KYCl₆ according to claim 1, characterized in that, The preparation method of the red-light barium gadolinium oxychloride niobate powder is as follows: barium carbonate, gadolinium oxide, niobium pentoxide, barium chloride dihydrate, manganese dioxide and chromium oxide are added to a mortar, deionized water is added and wet-milled to obtain a mixed slurry. The mixed slurry is then transferred to a tube furnace, and the tube furnace is heated to 1200-1250℃ at 3-5℃ / min and held for 6-8 hours. After post-treatment, the red-light barium gadolinium oxychloride niobate powder is obtained.

8. The high color rendering white LED material of rare earth doped Cs₂KYCl₆ according to claim 7, characterized in that, In the preparation of red-light barium gadolinium oxychloride powder, the ratio of barium carbonate, gadolinium oxide, niobium pentoxide, barium chloride dihydrate, manganese dioxide, chromium oxide and deionized water is 4.0-4.2g:2g:3.0-3.2g:1.6-1.8g:0.01-0.02g:0.01-0.02g:8-10mL.

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