A novel fluorescent powder and a fluorescent powder glass composite material comprising the same

Abstract

The application discloses a novel fluorescent powder and a fluorescent powder glass composite material containing the same, and belongs to the field of solid-state luminescent materials. The application significantly improves the thermal stability of the fluorescent powder by constructing an inorganic oxide film layer on the surface of the fluorescent powder. Meanwhile, on the basis of selecting a borosilicate system as a matrix glass, the application innovatively introduces a TiO2-ZnO-Li2O ternary synergistic system, effectively solving technical problems such as insufficient thermal conductivity, easy interface reaction and refractive index mismatch of the fluorescent glass. The prepared fluorescent powder glass composite material can generate high-quality ideal white light under the excitation of a blue LED chip, meeting the demand of new energy automobile headlight systems for high efficiency, long service life and good environmental adaptability. In addition, the preparation process provided by the application is simple and low in cost, the obtained product is excellent in thermal conductivity, and is suitable for large-scale production.

Description

Technical Field

[0001] This invention belongs to the field of solid-state luminescent materials, specifically relating to a novel phosphor and a phosphor-glass composite material containing the phosphor. Background Technology

[0002] High-power white LEDs possess numerous advantages such as high efficiency, good stability, long lifespan, and small size, leading to their widespread application in indoor and outdoor lighting, making them a rapidly developing sunrise industry globally. Currently, most industrial-scale white LED device fabrication utilizes a blue LED chip encapsulated with phosphor adhesive (organic polymer-coated YAG phosphor). However, with the increasing power of white LED devices, the poor thermal conductivity and tendency of organic polymers to yellow under prolonged heating severely impact the luminous performance and light extraction efficiency of white LED devices. To address this challenge, researchers have turned their attention to novel phosphor conversion materials. However, the high cost of most phosphor conversion materials hinders large-scale industrial applications, and their optical properties cannot simultaneously meet the requirements of high luminous flux, high luminous efficiency, and the color temperature and color rendering index required for pure white lighting applications, thus restricting the development of high-power lighting sources.

[0003] Fluorescent glass possesses advantages such as adjustable refractive index, high thermal stability, and high thermal conductivity, making it a significant alternative to phosphor adhesives as encapsulation materials, thus improving the light output efficiency and thermal reliability of white LED devices. Furthermore, compared to single-crystal phosphors (SCPs) and phosphor ceramics (TCPs), fluorescent glass offers more flexible and adjustable luminescent properties, simpler fabrication processes, and lower overall costs, making it a hot research topic in solid-state lighting fluorescence conversion materials. Chinese patent CN107572777A discloses a rapid synthesis method for phosphor-tellurate fluorescent glass. This method involves heating and melting a TeO2-ZnO-Na2O glass matrix powder, then adding phosphor and stirring for 3-10 seconds, followed by cooling and annealing to obtain the phosphor-glass composite material. This approach selects a low-melting-point tellurate glass matrix to match the refractive index of the phosphor (n>1.8), neglecting the high cost, insufficient processability, and difficulty in large-scale mass production of tellurate glass systems. Chinese patent CN112079578A discloses a method for preparing fluorescent glass. First, tetraethyl orthosilicate reacts with ZrF4 at 300 °C to generate zirconium silicate. Zirconium silicate has a high refractive index, which can significantly improve the refractive index of the fluorescent glass. Then, the temperature is raised to 1100 °C for pre-sintering for 3 h, allowing Al2O3, Lu2O3, and CeO2 to react directly at high temperature to form Lu3Al5O3. 12 :Ce 3+ Yellow phosphor; Eu₂O₃, CaCO₃, and silicon dioxide react directly at high temperature to form Ca₃Si₂O₇:Eu2+ Red phosphor is used, eliminating the need for additional phosphor. The prepared glass powder slurry is uniformly printed onto the substrate glass surface using a multi-layer screen printing method, followed by low-temperature co-sintering to obtain fluorescent glass. This method utilizes honeycomb multi-layer screen printing technology to suppress total internal reflection loss on the fluorescent glass surface, improving the optical performance of white LEDs. However, the overall method is complex, and the prepared fluorescent glass has an excessively high color temperature, making it unsuitable for large-scale industrial production. Chinese patent CN117383824A discloses a fluorescent glass material for high-power LEDs, its preparation method, and its application using Y3Al5O4. 12 :Ce 3+ Phosphors are mixed with low-melting-point glass powder (SiO2-B2O3-Al2O3-CaO-Y2O3-Na2O), pressed into a compact, sintered, and then cut, ground, and polished to obtain a yellow fluorescent conversion material. By optimizing the phosphor concentration and the thickness of the fluorescent glass, the white light spectrum color temperature, color rendering index, and color coordinates can be easily controlled, with a maximum luminous efficiency of ~140 lm / W. This scheme considers the thermal quenching temperature of the phosphor and therefore selects low-melting-point glass powder; however, the sintering temperature of this scheme is still higher than 800℃, close to that of Y3Al5O3. 12 :Ce 3+ The thermal quenching temperature of phosphors has a certain impact on their performance, and Y2O3 is relatively expensive, which is not conducive to large-scale production. In general, current phosphor glasses designed for high-power LEDs still have many shortcomings, and it is difficult to obtain phosphor glass composite materials that combine low cost, simple processing technology, and high lumen efficiency. Summary of the Invention

[0004] To address the problems of high cost, complex preparation process, and excessively high sintering temperature in the preparation of YAG:Ce (phosphor) based fluorescent conversion materials, this invention provides an efficient and reliable method for preparing phosphor coating and phosphor glass composite materials for LEDs.

[0005] The objective of this invention can be achieved through the following technical solutions: A novel phosphor, the preparation method of which includes the following steps: S1. Weigh out the corresponding amount of yttrium (Y) compound according to the coating amount of Y2O3, and dissolve it in a mixed solvent of anhydrous ethanol and deionized water; S2. Add ammonia water dropwise to adjust the pH value of the solution to obtain Y(OH)3 sol; S3. Add phosphor to Y(OH)3 sol to prepare a coated phosphor suspension; S4. The coated phosphor suspension is separated by centrifugation to obtain the coated phosphor. S5. The coated phosphor is washed with water, dehydrated and dried, and then ignited to obtain Y2O3 coated phosphor.

[0006] Furthermore, the coating amount of Y2O3 is 5 wt%~30 wt%.

[0007] Furthermore, the yttrium (Y)-containing compound is Y(NO3)3·6H2O, Y2Si2O7, or C6O. 12 One or more of Y2.

[0008] Furthermore, in step S2, the pH of the solution is adjusted to between 6 and 10.

[0009] Furthermore, in step S5, the calcination temperature of the coated phosphor is 300 ℃~900 ℃, and the time is 2 h~4 h.

[0010] The present invention also provides a phosphor glass composite material containing the above-mentioned phosphor, the preparation method of which includes the following steps: (1) Accurately weigh the glass raw materials, mix them evenly, heat and melt them, and then quench the resulting molten glass liquid. (2) Grind the quenched glass block into powder to obtain glass precursor powder; (3) The phosphor coated with Y2O3 is uniformly mixed with the glass precursor powder and pressed into a blank; (4) Place the blank into a muffle furnace and sinter it into shape. After cooling in the furnace, obtain a fluorescent glass composite material.

[0011] Further, the composition of the glass matrix is ​​(by mass percentage): 30 wt%~60 wt% SiO2, 25 wt%~45 wt% B2O3, 0 wt%~10 wt% Al2O3, 0 wt%~5 wt% TiO2, 5 wt%~20 wt% ZnO, 0 wt%~5 wt% RO, and 0 wt%~15 wt% R2O, wherein RO is one or more of CaO, BaO, and MgO, and R2O is one or more of Na2O, K2O, and Li2O.

[0012] Furthermore, the heating and melting parameters in step (1) are: temperature 1300 ℃~1500 ℃, time 60 min~120 min.

[0013] Furthermore, the Y2O3-coated phosphor and the glass precursor powder are mixed in a mass ratio of (7~10):(1~4).

[0014] Furthermore, the heating parameters of the muffle furnace in step (4) are: temperature 650 ℃~850 ℃, time 10 min~30 min.

[0015] The beneficial effects of this invention are: (1) Y2O3 has a high melting point (about 2439°C) and a low coefficient of thermal expansion (about 7×10⁻). 6 K⁻ 1 ~8×10⁻ 6 K⁻ 1 ), and the coefficient of thermal expansion of the Ce:YAG matrix (approximately 7×10⁻ 6 K⁻ 1 ~8×10⁻ 6 K⁻ 1 High degree of matching. This matching significantly reduces the thermal stress between the coating layer and the phosphor core, avoiding interface cracking or peeling caused by thermal expansion mismatch during high-temperature sintering or working environment.

[0016] (2) Ce in Ce:YAG 3 ⁺ It is easily oxidized to non-luminescent Ce in high temperature or oxygen-containing environments. 4 ⁺, The Y₂O₃ coating acts as a physical barrier, inhibiting Ce 3 ⁺Oxidation and glass matrix erosion.

[0017] (3) The Y2O3 coating passivates the surface defects of Ce:YAG, reduces non-radiative recombination channels, improves internal quantum efficiency, and suppresses fluorescence quenching and concentration quenching.

[0018] (4) Since the coating reaction is carried out by a heterogeneous nucleation mechanism, it can be ensured that the coating material first nucleates on the phosphor surface, and the ions of the coating material are uniformly dispersed in the entire suspension system by rapid stirring, thereby ensuring continuous and uniform growth of the film layer.

[0019] (5) Compared with the prior art, this invention constructs a ternary synergistic system (TiO2-ZnO-Li2O) based on a borosilicate system as the matrix glass. This system combines the high refractive index of TiO2, the heat dissipation properties of ZnO, and the low-temperature sintering characteristics of Li2O within the matrix glass. Through low-temperature co-firing technology, composite fluorescent glass can be prepared in air without atmospheric protection. Compared with similar borosilicate glasses, the composite fluorescent glass prepared by this process has a lower sintering temperature, effectively avoiding the defects of Y3Al5O3. 12 :Ce 3+ Phosphors exhibit thermal quenching due to excessively high sintering temperatures, and possess strong luminous intensity and transmittance, making them promising candidates for application in new energy vehicle lighting systems.

[0020] (6) The glass matrix system of the present invention has simple and readily available components, low cost, and the preparation process of fluorescent glass is simple, with excellent optical properties and excellent chemical stability, making it suitable for industrial production. Attached Figure Description

[0021] The invention will now be further described with reference to the accompanying drawings.

[0022] Figure 1 To prepare a novel phosphor (Y2O3 coated with Y3Al5O3) in this invention 12 :Ce 3+ A schematic diagram of the process for obtaining phosphors; Figure 2 The following are physical images (a) and (b) of the 450 nm blue light chip packaged according to embodiments of the present invention. Figure 3 The emission spectra of the fluorescent glasses prepared in Examples 1-3 and Comparative Examples 1 and 2 of this invention are shown. Detailed Implementation

[0023] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0024] Example 1 Y2O3 coating Y3Al5O 12 :Ce 3+ fluorescent powder, such as Figure 1 As shown: S1. Weigh out the corresponding amount of Y(NO3)3·6H2O according to the weight ratio of Y2O3 to phosphor of 1:20. Dissolve the yttrium salt in a mixed solvent of anhydrous ethanol and deionized water and stir it thoroughly on a magnetic stirrer until it is completely dissolved to obtain a clear solution. S2. Slowly add ammonia water to the clear liquid to adjust the pH value of the solution to 6, and obtain Y(OH)3 sol; S3. Slowly add the phosphor to the Y(OH)3 sol to obtain a coated phosphor suspension; S4. The coated phosphor suspension is separated by centrifugation to obtain the coated phosphor. S5. After washing, dehydrating and drying the coated phosphor, calcine it at 300℃ for 1 hour to obtain Y2O3-coated Ce:YAG phosphor.

[0025] Preparation of phosphor glass composite materials: (1) Accurately weigh the glass raw materials, mix them evenly to obtain a batch; heat the batch to 1500℃ and keep it at that temperature for 60 min; then quench the obtained molten glass liquid; wherein, the mass percentage of the glass powder components of the fluorescent glass is 40wt% SiO2, 20wt% B2O3, 9wt% Al2O3, 5wt% CaO, 6wt% Na2O, 4wt% MgO, 2wt% Li2O, 1.5wt% TiO2, 10wt% ZnO, and 2.5wt% K2O.

[0026] (2) Grind the water-quenched glass block into powder to obtain glass precursor powder; (3) The above precursor glass powder is mixed with Y3Al5O treated with Y2O3. 12 :Ce 3+ Yellow fluorescent powder is mixed uniformly at a mass ratio of 10:1 and compressed into a preform. (4) The blank is placed in a muffle furnace and heated to 750 °C and held for 15 min to sinter and form. After cooling in the furnace, the fluorescent glass composite material is obtained.

[0027] like Figure 2 As shown, after the above-mentioned phosphor glass composite material is cut and polished, it is packaged with the LED blue light chip and then the performance of color temperature (CCT), color rendering index (CRI), color coordinate (CIE), luminous flux (LF) and luminous efficacy (LE) are tested.

[0028] Example 2 Y2O3 coating Y3Al5O 12 :Ce 3+ fluorescent powder: S1. Weigh out the corresponding amount of Y(NO3)3·6H2O according to the weight ratio of Y2O3 to phosphor of 1:10. Dissolve the yttrium salt in a mixed solvent of anhydrous ethanol and deionized water and stir it thoroughly on a magnetic stirrer until it is completely dissolved to obtain a clear solution. S2. Slowly add ammonia water to the clear solution to adjust the pH value of the solution to 8, and obtain Y(OH)3 sol; S3. Slowly add the phosphor to the Y(OH)3 sol to obtain a coated phosphor suspension; S4. The coated phosphor suspension is separated by centrifugation to obtain the coated phosphor. S5. After washing, dehydrating and drying the coated phosphor, calcine it at 600 °C for 1 h to obtain Y2O3-coated Ce:YAG phosphor.

[0029] Preparation of phosphor glass composite materials: (1) Accurately weigh the glass raw materials, mix them evenly to obtain the batch material; heat the batch material to 1500 ℃ and keep it at that temperature for 60 min; then quench the obtained molten glass liquid; wherein, the mass percentage of the glass powder components of the fluorescent glass is 40wt% SiO2, 20wt% B2O3, 9wt% Al2O3, 5wt% CaO, 6wt% Na2O, 4wt% MgO, 2wt% Li2O, 1.5wt% TiO2, 10wt% ZnO, and 2.5wt% K2O.

[0030] (2) Grind the water-quenched glass block into powder to obtain glass precursor powder; (3) The above precursor glass powder is mixed with Y3Al5O treated with Y2O3. 12 :Ce 3+ Yellow fluorescent powder is mixed uniformly at a mass ratio of 10:1 and compressed into a preform. (4) The blank is placed in a muffle furnace and heated to 750 °C and held for 15 min to sinter and form. After cooling in the furnace, the fluorescent glass composite material is obtained.

[0031] After the above-mentioned phosphor glass composite material is cut and polished, it is packaged with LED blue light chip and then the performance of color temperature (CCT), color rendering index (CRI), color coordinate (CIE), luminous flux (LF) and luminous efficacy (LE) are tested.

[0032] Example 3 Y2O3 coating Y3Al5O 12 :Ce 3+ fluorescent powder: S1. Weigh out the corresponding amount of Y(NO3)3·6H2O according to the weight ratio of Y2O3 to phosphor of 1:5. Dissolve the yttrium salt in a mixed solvent of anhydrous ethanol and deionized water and stir it thoroughly on a magnetic stirrer until it is completely dissolved to obtain a clear solution.

[0033] S2. Slowly add ammonia water to the clear solution to adjust the pH value of the solution to 10, and obtain Y(OH)3 sol; S3. Slowly add the phosphor to the Y(OH)3 sol to obtain a coated phosphor suspension; S4. The coated phosphor suspension is separated by centrifugation to obtain the coated phosphor. S5. After washing, dehydrating and drying the coated phosphor, calcine it at 900 °C for 1 h to obtain Y2O3-coated Ce:YAG phosphor.

[0034] Preparation of phosphor glass composite materials (1) Accurately weigh the glass raw materials, mix them evenly to obtain the batch material; heat the batch material to 1500 ℃ and keep it at that temperature for 60 min; then quench the obtained molten glass liquid; wherein, the mass percentage of the glass powder components of the fluorescent glass is 40wt% SiO2, 20wt% B2O3, 9wt% Al2O3, 5wt% CaO, 6wt% Na2O, 4wt% MgO, 2wt% Li2O, 1.5wt% TiO2, 10wt% ZnO, and 2.5wt% K2O.

[0035] (2) Grind the water-quenched glass block into powder to obtain glass precursor powder; (3) The above precursor glass powder is mixed with Y3Al5O treated with Y2O3. 12 :Ce 3+ Yellow fluorescent powder is mixed uniformly at a mass ratio of 10:1 and compressed into a preform. (4) The blank is placed in a muffle furnace and heated to 750 °C and held for 15 min to sinter and form. After cooling in the furnace, the fluorescent glass composite material is obtained.

[0036] After the above-mentioned phosphor glass composite material is cut and polished, it is packaged with LED blue light chip and then the performance of color temperature (CCT), color rendering index (CRI), color coordinate (CIE), luminous flux (LF) and luminous efficacy (LE) are tested.

[0037] Comparative Example 1 Preparation of phosphor glass composite materials: S1. Accurately weigh the glass raw materials, mix them evenly to obtain a batch; heat the batch to 1500 ℃ and hold for 60 min; then quench the obtained molten glass; wherein, the mass percentage of the glass powder composition of the fluorescent glass is 40 wt% SiO2, 20 wt% B2O3, 9 wt% Al2O3, 5 wt% CaO, 6 wt% Na2O, 4 wt% MgO, 2 wt% Li2O, 1.5 wt% TiO2, 10 wt% ZnO, and 2.5 wt% K2O.

[0038] S2. Grind the water-quenched glass block into powder to obtain glass precursor powder; S3. The above-mentioned precursor glass powder is mixed with Y3Al5O that has not been coated with Y2O3. 12 :Ce 3+ Yellow fluorescent powder is mixed uniformly at a mass ratio of 10:1 and compressed into a preform. S4. Place the blank in a muffle furnace and heat it to 750 ℃ ​​and hold it for 15 min to sinter it into shape. After cooling in the furnace, the fluorescent powder glass composite material is obtained.

[0039] After the above-mentioned phosphor glass composite material is cut and polished, it is packaged with LED blue light chip and then the performance of color temperature (CCT), color rendering index (CRI), color coordinate (CIE), luminous flux (LF) and luminous efficacy (LE) are tested.

[0040] Comparative Example 2 Preparation of phosphor glass composite materials: S1. Accurately weigh the glass raw materials, mix them evenly to obtain a batch; heat the batch to 1500℃ and hold for 60 minutes; then quench the obtained molten glass; wherein, the glass powder composition of the fluorescent glass is 40wt% SiO2, 33.5wt% B2O3, 9wt% Al2O3, 5wt% CaO, 6wt% Na2O, 4wt% MgO, and 2.5wt% K2O by mass percentage.

[0041] S2. Grind the water-quenched glass block into powder to obtain glass precursor powder; S3. The above-mentioned precursor glass powder is mixed with Y3Al5O that has not been coated with Y2O3. 12 :Ce 3+ Yellow fluorescent powder is mixed uniformly at a mass ratio of 10:1 and compressed into a preform. S4. Place the blank in a muffle furnace and heat it to 750 ℃ ​​and hold it for 15 min to sinter it into shape. After cooling in the furnace, the fluorescent powder glass composite material is obtained.

[0042] After the above-mentioned phosphor glass composite material is cut and polished, it is packaged with LED blue light chip and then the performance of color temperature (CCT), color rendering index (CRI), color coordinate (CIE), luminous flux (LF) and luminous efficacy (LE) are tested.

[0043] like Figure 3 The emission spectra of the fluorescent glasses prepared in Examples 1-3 and Comparative Examples 1 and 2 are shown. Under excitation at 450 nm, its emission wavelength is located at 540 nm, corresponding to Ce. 3+ 5D1→ 2 The F7 / 2 electronic transition resulted in a composite fluorescent glass that maintained good luminescence performance, and this performance was further enhanced by the Y3Al5O4 transition. 12 :Ce 3+ As the concentration of yellow phosphor increases, its emission peak becomes stronger.

[0044] The glass raw materials and phosphors used in Examples 1-3 and Comparative Examples 1-2 are shown in Table 1 below: Table 1 The performance data of the high-performance phosphor glass composite materials of Examples 1-3 and Comparative Examples 1-2 are shown in Table 2 below: Table 2 As shown in Table 2, the addition of a ternary synergistic system (TiO2-ZnO-Li2O) to the borosilicate system and the addition of Y3Al5O 12 :Ce 3+ The surface of the yellow phosphor is coated with Y2O3, which can easily control the color temperature, color rendering index and color coordinates, and the luminous efficiency can reach up to 140 lm / W.

[0045] In summary, the Y3Al5O prepared by this invention... 12 :Ce 3+ The yellow phosphor glass composite material emits high-quality pure white light when excited by 450 nm blue light, making it suitable for high color rendering index white LED devices excited by blue LED chips.

[0046] The above detailed embodiments provide a specific description of the analytical methods involved in this invention. It should be noted that the above description is only intended to help those skilled in the art better understand the methods and ideas of this invention, and is not intended to limit the scope of the invention. Without departing from the principles of this invention, those skilled in the art can make appropriate adjustments or modifications to this invention, and such adjustments and modifications should also fall within the protection scope of this invention.

Claims

1. A novel phosphor, characterized in that, Its preparation method includes the following steps: S1. Weigh out the corresponding amount of yttrium-containing compound according to the coating amount of Y2O3, and dissolve it in a mixed solvent of anhydrous ethanol and deionized water. S2. Add ammonia water dropwise to adjust the pH value of the solution to obtain Y(OH)3 sol; S3. Add phosphor to Y(OH)3 sol to prepare a coated phosphor suspension; S4. The coated phosphor suspension is separated by centrifugation to obtain the coated phosphor. S5. The coated phosphor is washed with water, dehydrated and dried, and then ignited to obtain Y2O3 coated phosphor.

2. The novel phosphor according to claim 1, characterized in that, The coating amount of Y2O3 is 5 wt% to 30 wt%.

3. The novel phosphor according to claim 1, characterized in that, The yttrium-containing compounds are Y(NO3)3·6H2O, Y2Si2O7, and C6O. 12 One or more of Y2.

4. The novel phosphor according to claim 1, characterized in that, In step S2, adjust the pH of the solution to between 6 and 10.

5. The novel phosphor according to claim 1, characterized in that, In step S5, the calcination temperature of the coated phosphor is 300 ℃~900 ℃, and the time is 2 h~4 h.

6. A phosphor glass composite material comprising the phosphor as described in any one of claims 1-5, characterized in that, Its preparation method includes the following steps: (1) Accurately weigh the glass raw materials, mix them evenly, heat and melt them, and then quench the resulting molten glass liquid. (2) Grind the quenched glass block into powder to obtain glass precursor powder; (3) The phosphor coated with Y2O3 is uniformly mixed with the glass precursor powder and pressed into a blank; (4) Place the blank into a muffle furnace and sinter it into shape. After cooling in the furnace, obtain a fluorescent glass composite material.

7. The phosphor glass composite material according to claim 6, characterized in that, The glass matrix is ​​composed of: 30 wt%~60 wt% SiO2, 25 wt%~45 wt% B2O3, 0 wt%~10 wt% Al2O3, 0 wt%~5 wt% TiO2, 5 wt%~20 wt% ZnO, 0 wt%~5 wt% RO, and 0 wt%~15 wt% R2O, wherein RO is one or more of CaO, BaO, and MgO, and R2O is one or more of Na2O, K2O, and Li2O.

8. The phosphor glass composite material according to claim 6, characterized in that, The heating and melting parameters in step (1) are: temperature 1300 ℃~1500 ℃, time 60 min~120 min.

9. The phosphor glass composite material according to claim 6, characterized in that, The Y2O3-coated phosphor and the glass precursor powder are mixed in a mass ratio of (7~10):(1~4).

10. The phosphor glass composite material according to claim 6, characterized in that, In step (4), the muffle furnace heating parameters are: temperature 650 ℃~850 ℃, time 10 min~30 min.

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