High-color rendering index white light fluorescent powder capable of being excited by near ultraviolet light and preparation method of high-color rendering index white light fluorescent powder
By exciting Y2.94-xTbxSm0.06MgGa2AlGeO12 white phosphor with near-ultraviolet light and using rare earth ions terbium and samarium as luminescent centers, combined with the blue light emission of the compound, the problems of low color rendering index and complex production in the existing technology are solved, realizing the simple preparation of high color rendering index white light and spectral coverage of the entire visible light region.
Patent Information
- Application Number
- CN202511314275.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-15
- Publication Date
- 2026-02-03
AI Technical Summary
In existing white LED devices, the color rendering index is low when using blue light chips to excite yellow light YAG phosphors. Furthermore, the mixing of multiple components presents problems such as complex processes, severe self-absorption, and differences in aging rates, leading to spectral deviation and reduced luminous efficiency.
Near-ultraviolet light was used to excite Y2.94-xTbxSm0.06MgGa2AlGeO12 white phosphor. The trivalent rare earth ions terbium and samarium were used as isolated luminescent centers. Combined with the blue light emission of the compound itself, high color rendering index white light was achieved. The chemical composition is expressed as: Y2.94-xTb0.06MgGa2AlGeO12, where x is the doping content of Tb 0.075≤x≤0.105.
High color rendering index (Ra) and R9 (R9) greater than 90 can be achieved by sintering in a normal air atmosphere in the next step. The spectrum covers the entire visible light region of blue, green, and red light, which simplifies the production process, avoids the use of flammable and explosive atmospheres, and reduces reaction temperature and time.
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Figure CN121450329A_ABST
Abstract
Description
Technical fields:
[0001] This invention relates to the field of luminescent materials technology, and in particular to a high color rendering index white phosphor that can be excited by near-ultraviolet light and its preparation method. Background technology:
[0002] Classic white LED devices utilize blue LED chips to excite yellow YAG phosphors to produce white light. However, the limited spectral coverage of YAG phosphors often results in a low color rendering index (Ra < 80), making it unsuitable for indoor applications. To improve white light quality, additional red and cyan phosphors are added to form a chip that excites multiple mixed phosphors to obtain white light. However, this approach involves mixing various compound systems, leading to complex formulation processes, severe self-absorption by different components, varying aging rates, and asynchronous fluorescence quenching. These issues can easily cause the device's spectrum to deviate from the set parameters and severely affect its luminous efficiency. In contrast, another method for achieving white light—using near-ultraviolet (NUV) LED chips to excite a single-matrix white phosphor—offers significant advantages. By selecting appropriate compound systems and utilizing different types of luminescent centers, a sufficiently wide spectral coverage can be designed through a single-step synthesis process. The near-ultraviolet chip-loaded white phosphor fabrication process is simple, avoids component self-absorption within the device, and eliminates aging rate issues, making it an ideal iterative technology for white LED devices. Among these, obtaining the most crucial material, namely the high color rendering index white phosphor that can be excited by near-ultraviolet light, is of paramount importance. Summary of the Invention:
[0003] This invention solves the problems existing in the prior art and provides a high color rendering index white phosphor that can be excited by near-ultraviolet light and its preparation method. This white phosphor can be excited by near-ultraviolet light and emits red light with a strongest main peak at 617 nm, green light with a second strongest peak at 544 nm, and a broad-spectrum blue light covering 380-500 nm. The Y-band provided by this invention... 2.94- x Tb x Sm 0.06 MgGa2AlGeO 12 White phosphors not only possess the characteristic green light of terbium ions and the characteristic red light of samarium ions, but their matrix also has an additional broad-band blue light that is not a rare earth ion, thus obtaining white light with a high color rendering index (Ra) and R9 both greater than 90.
[0004] The first objective of this invention is to provide a high color rendering index white phosphor that can be excited by near-ultraviolet light, the chemical composition of which is expressed as: Y 2.94-x Tb x Sm 0.06 MgGa2AlGeO 12, where x is the doping content of Tb, and: 0.075≤x≤0.105.
[0005] The near-ultraviolet light-exciteable high color rendering index white phosphor proposed in this invention utilizes trivalent rare earth ions terbium and samarium as isolated luminescent centers to obtain corresponding green and red light emission, and combines the blue light emission of the compound itself to achieve white light. The advantage of this white light is that the color rendering index Ra and R9 are both greater than 90.
[0006] The near-ultraviolet light-exciteable high color rendering index white phosphor proposed in this invention utilizes trivalent rare earth ions terbium and samarium as isolated emitting centers to obtain corresponding green and red light emission, and combines this with the compound's own blue light emission to achieve white light. The advantage of this white light is that both the color rendering index Ra and R9 are greater than 90. The Y-type phosphor provided by this invention... 2.94- x Tb x Sm 0.06 MgGa2AlGeO 12 The synthesis process of white phosphor can be carried out in a single sintering step under ordinary air atmosphere. Compared with common single-matrix white phosphor containing divalent rare earth ions europium or trivalent rare earth ions cerium, it does not require the use of flammable and explosive reducing atmospheres such as hydrogen and carbon monoxide. The reaction temperature is lower, the reaction time is shorter, and the production is simpler and faster.
[0007] The second objective of this invention is to provide a method for preparing the near-ultraviolet light-exciteable high color rendering index white phosphor, comprising the following steps: weighing raw materials containing yttrium, samarium, magnesium, gallium, aluminum, germanium and terbium according to their chemical composition, wherein the molar ratio of each metal element is Y:Sm:Mg:Ga:Al:Ge:Tb=2.94-x:0.06:1:2:1:1:x, wherein: 0.075≤x≤0.105. During this process, Ga will sublimate and be lost during the high-temperature reaction, so a certain amount of Ga2O3 needs to be added. The mixture is thoroughly ground to make it uniform, and then placed in a reaction vessel for sintering in an atmospheric pressure air atmosphere. After cooling to room temperature and grinding, the near-ultraviolet light-exciteable high color rendering index white phosphor is obtained.
[0008] The design and implementation of this invention enable the production of single-matrix white light covering the entire visible light spectrum, including blue, green, and red, under a non-reducing atmosphere. Furthermore, the fabrication process of this invention is simple and can be carried out using general equipment and in ordinary air environments, greatly enhancing its practicality and feasibility.
[0009] The Y provided by this invention 2.94-x Tb x Sm 0.06 MgGa2AlGeO 12The synthesis process of white phosphor can be carried out in a single sintering step under ordinary air atmosphere. Compared with common single-matrix white phosphor containing divalent rare earth ions europium or trivalent rare earth ions cerium, it does not require the use of flammable and explosive reducing atmospheres such as hydrogen and carbon monoxide. The reaction temperature is lower, the reaction time is shorter, and the production is simpler and faster.
[0010] Preferably, the raw materials containing yttrium, samarium, and terbium are selected from one or more of the oxides, oxalates, carbonates, and nitrates of yttrium, samarium, and terbium. The raw materials containing yttrium are selected from one or more of yttrium oxide, yttrium oxalate, yttrium carbonate, and yttrium nitrate; the raw materials containing samarium are selected from one or more of samarium oxide, samarium oxalate, samarium carbonate, and samarium nitrate; and the raw materials containing terbium are selected from one or more of terbium oxide, terbium oxalate, terbium carbonate, and terbium nitrate.
[0011] Preferably, the magnesium-containing raw material is selected from magnesium hydroxide.
[0012] Preferably, the gallium-containing raw material is selected from gallium oxide.
[0013] Preferably, the aluminum-containing raw material is selected from aluminum hydroxide.
[0014] Preferably, the germanium-containing raw material is selected from germanium oxide.
[0015] Preferably, the sintering conditions are: a single-step sintering process, with a temperature of 1275℃-1375℃ and a time of 6-10 hours. More preferably, the sintering step is: heating from room temperature to 1300±25℃ at a rate of 5℃ / min, and reacting at a constant temperature for 8 hours.
[0016] Preferably, to compensate for the loss of Ga during the high-temperature reaction, an additional 10% of Ga2O3 needs to be added on top of the stoichiometric ratio.
[0017] This invention also protects the application of the near-ultraviolet light-exciteable high color rendering index white phosphor in the fields of full-spectrum health lighting, plant growth lighting, high-precision and high-definition display, or non-contact optical temperature measurement.
[0018] Compared with the prior art, the present invention has the following advantages:
[0019] 1. The white phosphor proposed in this invention utilizes trivalent rare earth ions terbium and samarium as isolated luminescent centers to obtain corresponding green and red light emission, and combines this with the compound's own blue light emission to achieve white light. Its fluorescence spectrum exhibits a strong main peak at 617 nm red light, a secondary peak at 544 nm green light, and a broad blue light band covering 380-500 nm, demonstrating a wide spectral coverage. The color rendering index Ra and R9 index of the white light are both greater than 90.
[0020] 2. The synthesis reaction process of the white phosphor proposed in this invention only requires one sintering step under ordinary air atmosphere. Compared with common single-matrix white phosphors containing divalent rare earth ions europium or trivalent rare earth ions cerium, it does not require the use of flammable and explosive reducing atmospheres such as hydrogen and carbon monoxide. The reaction temperature is lower, the reaction time is shorter, and the production is simpler and faster. Attached image description:
[0021] Figure 1 This is the X-ray powder diffraction pattern of the high color rendering index white phosphor prepared in Example 1;
[0022] Figure 2 This is the fluorescence emission spectrum of the high color rendering index white phosphor prepared in Example 1;
[0023] Figure 3 This is a color coordinate diagram and a list of color rendering indices for the high color rendering index white phosphor prepared in Example 1. Detailed implementation method:
[0024] The following embodiments are further illustrations of the present invention, but not limitations thereof.
[0025] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention. Unless otherwise specified, the experimental materials and reagents used herein are commercially available products conventionally available in this technical field.
[0026] Example 1
[0027] Weigh out 0.3218 g of yttrium oxide (Y₂O₃), 0.0168 g of terbium oxide (Tb₄O₇), 0.0105 g of samarium oxide (Sm₂O₃), 0.0583 g of magnesium hydroxide (Mg(OH)₂), 0.2062 g of gallium oxide (Ga₂O₃), 0.0780 g of aluminum hydroxide (Al(OH)₃), and 0.1046 g of germanium oxide (GeO₂). Grind the above raw materials in an agate mortar until uniform. After grinding, carry out a solid-state reaction. In an atmospheric pressure environment, heat the mixture from room temperature to 1325°C at a rate of 5°C / min, and hold it at this temperature for 8 hours. After the reaction, allow it to cool naturally and grind it until uniform to obtain Y₂O₃. 2.94-x Tb x Sm 0.06 MgGa2AlGeO 12 White fluorescent powder.
[0028] X-ray powder diffraction pattern, fluorescence emission spectrum, and color coordinate diagram of white phosphor are as follows: Figure 1-3As shown, under near-ultraviolet light excitation, the strongest main peak of this fluorescence spectrum is at 617 nm red light, the second strongest peak is at 544 nm green light, and a broad blue light band covering 380-500 nm. The color coordinates are located at (0.3608, 0.3127), and the color rendering index Ra and R9 are both greater than 90.
[0029] Example 2
[0030] Weigh out 0.3235g of yttrium oxide (Y₂O₃), 0.0140g of terbium oxide (Tb₄O₇), 0.0105g of samarium oxide (Sm₂O₃), 0.0583g of magnesium hydroxide (Mg(OH)₂), 0.2062g of gallium oxide (Ga₂O₃), 0.0780g of aluminum hydroxide (Al(OH)₃), and 0.1046g of germanium oxide (GeO₂). Grind the above raw materials in an agate mortar until uniform. After grinding, carry out a solid-state reaction. In an atmospheric pressure environment, heat the mixture from room temperature to 1375℃ at a rate of 5℃ / min, and hold it at this temperature for 6 hours. After the reaction, allow it to cool naturally and grind it until uniform to obtain Y₂O₃. 2.94-x Tb x Sm 0.06 MgGa2AlGeO 12 White fluorescent powder.
[0031] Example 3
[0032] Weigh out 0.3201g of yttrium oxide (Y₂O₃), 0.0196g of terbium oxide (Tb₄O₇), 0.0105g of samarium oxide (Sm₂O₃), 0.0583g of magnesium hydroxide (Mg(OH)₂), 0.2062g of gallium oxide (Ga₂O₃), 0.0780g of aluminum hydroxide (Al(OH)₃), and 0.1046g of germanium oxide (GeO₂). Grind the above raw materials in an agate mortar until uniform. After grinding, carry out a solid-state reaction. In an atmospheric pressure environment, heat the mixture from room temperature to 1275℃ at a rate of 5℃ / min, and hold it at this temperature for 10 hours. After the reaction, allow it to cool naturally and grind it until uniform to obtain Y₂O₃. 2.94-x Tb x Sm 0.06 MgGa2AlGeO 12 White fluorescent powder.
[0033] The above description of the embodiments is only for the purpose of helping to understand the technical solution and core idea of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principle of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.
Claims
1. A near-ultraviolet light excitable high color rendering index white light phosphor, characterized by, The chemical composition is represented by the formula: Y 2.94-x Tb x Sm 0.06 MgGa2AlGeO 12 x is the doping content of Tb, wherein: 0.075≤x≤0.
105.
2. The method of producing a near-ultraviolet light excitable high color rendering index white light fluorescent powder according to claim 1, characterized by, The method comprises the following steps: taking raw materials containing yttrium, samarium, magnesium, gallium, aluminum, germanium and terbium respectively according to chemical composition, the molar ratio of each metal element is Y:Sm:Mg:Ga:Al:Ge:Tb=2.94-x:0.06:1:2:1:1:x, wherein 0.075<=x<=0.105, Ga is lost by sublimation in the high-temperature reaction process, and a certain amount of Ga2O3 needs to be additionally added, the mixture is fully ground and put into a reaction container, sintering is carried out in an air atmosphere at normal pressure, and after cooling to room temperature, the high color rendering index white light fluorescent powder excited by near-ultraviolet light is obtained after grinding.
3. The production method according to claim 2, characterized by, The raw material containing yttrium, samarium and terbium is selected from one or more of oxides, oxalates, carbonates and nitrates of yttrium, samarium and terbium.
4. The production method according to claim 2, characterized by, The raw material containing magnesium is magnesium hydroxide.
5. The preparation method according to claim 2, characterized in that, The raw material containing gallium is gallium oxide.
6. The preparation method according to claim 2, characterized in that, The raw material containing aluminum is aluminum hydroxide.
7. The preparation method according to claim 2, characterized in that, The raw material containing germanium is germanium oxide.
8. The preparation method according to claim 2, characterized in that, The sintering specific condition is one-step sintering at a temperature of 1275-1375 DEG C for 6-10 hours.
9. The method of claim 2, wherein, The loss of Ga in the high-temperature reaction process needs to be compensated by additionally adding 10% Ga2O3 based on the stoichiometric ratio.
10. The application of the high color rendering index white light fluorescent powder excited by near-ultraviolet light in the field of lighting, high-precision high-definition display or non-contact optical temperature measurement.