ANTI-DETERIORATION RED PHOSPHOR, AND PREPARATION METHOD AND APPLICATION THEREOF
20260008956 ยท 2026-01-08
Assignee
Inventors
- Jinhua He (Jiangsu, CN)
- Chao Liang (Jiangsu, CN)
- Leqi Yao (Jiangsu, CN)
- Bo Zhong (Jiangsu, CN)
- Jing WANG (Jiangsu, CN)
Cpc classification
International classification
C09K11/61
CHEMISTRY; METALLURGY
Abstract
The present application discloses an anti-deterioration red phosphor, and a preparation method and an application thereof, and relates to the field of phosphor materials technology. The anti-deterioration red phosphor of the present application comprises a core-shell structure, the core-shell structure comprises an inner core and an outer shell, the inner core and the outer shell are independently selected from substances shown in a chemical formula I, and the chemical formula I is A.sub.2M.sub.(1-x)F.sub.6:xMn.sup.4+. The present application enhances the moisture resistance and anti-deterioration resistance of the phosphor by controlling the atom percentage of Mn.sup.4+ to be the lowest in the innermost layer of the inner core and the highest in the outermost layer of the inner core. Additionally, by incorporating an outer shell with minimal or even no Mn.sup.4+ content to encapsulate the inner core of the phosphor, it helps maintain a higher luminescent efficiency in coordination with the inner core.
Claims
1. An anti-deterioration red phosphor, wherein the anti-deterioration red phosphor comprises a core-shell structure, the core-shell structure comprises an inner core and an outer shell, the inner core and the outer shell are independently selected from substances shown in a chemical formula I; A.sub.2M.sub.(1-x)F.sub.6:xMn.sup.4+ the chemical formula I; in the chemical formula I, the A comprises at least one of Li, Na, K, Rb and Cs, and the M comprises at least one of Si, Ge and Ti; wherein, an atom percentage of Mn.sup.4+ in an innermost layer of the inner core is a, and an atom percentage of Mn.sup.4+ in an outermost layer of the inner core is b, and b>a; and the atom percentage of Mn.sup.4+ in each place inside a particle of the inner core is x.sub.1, and a value range of the x.sub.1 is a<x.sub.1<b; and the atom percentage of Mn.sup.4+ in the outer shell is x.sub.2, and a value range of the x.sub.2 is 0x.sub.20.1%.
2. The anti-deterioration red phosphor of claim 1, wherein the x.sub.1 is in an increasing trend from an inside to an outside in a radial direction of the inner core.
3. The anti-deterioration red phosphor of claim 2, wherein the increasing trend is that the x.sub.1 increases linearly and uniformly from the inside to the outside in the radial direction of the inner core.
4. The anti-deterioration red phosphor of claim 1, wherein, in the inner core, a value range of the a is 0a0.1%, and a value range of the b is 0.3%b5%.
5. The anti-deterioration red phosphor of claim 4, wherein, in the inner core, the value range of the a is 0a0.01%, and the value range of the b is 0.5%b1.5%.
6. The anti-deterioration red phosphor of claim 1, wherein, in the phosphor, b>x.sub.2.
7. The anti-deterioration red phosphor of claim 1, wherein, in the phosphor, 0x.sub.2/b 1/10.
8. The anti-deterioration red phosphor of claim 1, wherein, an average particle size of the anti-deterioration red phosphor is 5-40 m; and an average thickness of the outer shell is 0.1-2 m.
9. A preparation method for an anti-deterioration red phosphor, wherein the anti-deterioration red phosphor comprises a core-shell structure, the core-shell structure comprises an inner core and an outer shell, the inner core and the outer shell are independently selected from substances shown in a chemical formula I; A.sub.2M.sub.(1-x)F.sub.6:xMn.sup.4+ the chemical formula I; in the chemical formula I, the A comprises at least one of Li, Na, K, Rb and Cs, and the M comprises at least one of Si, Ge and Ti: wherein, an atom percentage of Mn.sup.4+ in an innermost layer of the inner core is a, and an atom percentage of Mn.sup.4+ in an outermost layer of the inner core is b, and b>a; and the atom percentage of Mn.sup.4+ in each place inside a particle of the inner core is x.sub.1, and a value range of the x.sub.1 is a<x.sub.1<b; and the atom percentage of Mn.sup.4+ in the outer shell is x.sub.2, and a value range of the x.sub.2 is 0x.sub.20.1%, wherein the preparation method comprises following steps: (1) dissolving a salt of the A in a hydrofluoric acid solution, denoted as a base liquid A solution; (2) preparing a series of BX solutions with different concentrations of K.sub.2MnF.sub.6 by taking a series of the K.sub.2MnF.sub.6 and dissolving the series of the K.sub.2MnF.sub.6 in equal masses of H.sub.2MF.sub.6 solutions; and (3) adding the series of the BX solutions into the base liquid A solution in turn, controlling a concentration of the K.sub.2MnF.sub.6 in the BX solution added for a first time is the lowest, controlling the concentration of K.sub.2MnF.sub.6 in the BX solution added for a last time is the highest, obtaining an inner core mixed system to prepare the inner core, and adding the H.sub.2MF.sub.6 solution into the inner core mixed system to prepare the outer shell to obtain the anti-deterioration red phosphor; wherein, the salt of the A is selected from at least one of a fluoride, a hydrogen fluoride salt, a sulfate, a nitrate, a sulfuric acid hydrogen salt, a carbonate, and a bicarbonate of the A, and the A is selected from any one of Li, Na, K, Rb and Cs; and in the K.sub.2MF.sub.6, the M is selected from any one of Si, Ge and Ti.
10. The preparation method for the anti-deterioration red phosphor of claim 9, wherein, in step (3), the adding the series of the BX solutions into the base liquid A solution in turn is adding the series of the BX solutions into the base liquid A solution in an order of increasing concentrations of the K.sub.2MnF.sub.6 in turn.
11. The preparation method for the anti-deterioration red phosphor of claim 10, wherein, in step (2), the taking the series of the K.sub.2MnF.sub.6 is taking the K.sub.2MnF.sub.6 with masses increasing in a form of an arithmetic sequence.
12. The preparation method for the anti-deterioration red phosphor of claim 9, wherein, a mass concentration of the H.sub.2MF.sub.6 solution is 10-15%, and mass of K.sub.2MnF.sub.6 used for each 5 g H.sub.2MF.sub.6 in the series of the BX solutions is 0-3 g; and a mass concentration of the hydrofluoric acid solution is 35-55%; and in the base liquid A solution, a volume of the hydrofluoric acid solution used for each 15-25 g the salt of the A is 200-300 mL.
13. The preparation method for the anti-deterioration red phosphor of claim 9, wherein, in step (3), mass of the series of the BX solutions added is 100-1300 g; and mass of the H.sub.2MF.sub.6 solution added is 5-200 g in the adding the H.sub.2MF.sub.6 solution into the inner core mixed system.
14. Use of the anti-deterioration red phosphor of claim 1 in a field of an LCD backlight source or a field of LED lighting.
15. An LCD backlight source, wherein, the LCD backlight source comprises an excitation chip and a phosphor coated on the excitation chip; the phosphor is the anti-deterioration red phosphor of claim 1.
16. A lighting device, wherein, the lighting device comprises a light emitting device; the light emitting device comprises an excitation chip and a phosphor coated on the excitation chip; the phosphor is the anti-deterioration red phosphor of claim 1.
17. A lighting device, wherein, the lighting device comprises a light emitting device; the light emitting device comprises an excitation chip and a phosphor coated on the excitation chip; the phosphor is the anti-deterioration red phosphor of claim 2.
18. A lighting device, wherein, the lighting device comprises a light emitting device; the light emitting device comprises an excitation chip and a phosphor coated on the excitation chip; the phosphor is the anti-deterioration red phosphor of claim 3.
19. A lighting device, wherein, the lighting device comprises a light emitting device; the light emitting device comprises an excitation chip and a phosphor coated on the excitation chip; the phosphor is the anti-deterioration red phosphor of claim 4.
20. A lighting device, wherein, the lighting device comprises a light emitting device; the light emitting device comprises an excitation chip and a phosphor coated on the excitation chip; the phosphor is the anti-deterioration red phosphor of claim 5.
Description
DESCRIPTION OF DRAWINGS
[0035]
[0036]
[0037]
[0038]
[0039]
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0040] In order to make the purpose, technical scheme and advantages of the present application more clear, the following combined with the implementation examples, the present application is further described in detail. It should be understood that the following implementation method are only exemplary implementation methods used to illustrate the principle of the present application. That is, in the red phosphor A.sub.2M.sub.(1-x)F.sub.6:xMn.sub.4+. Preferably, the A and the M prefer K and Si, respectively., and the synthetic raw materials prefer potassium hydrogen difluoride, fluosilicic acid and so on. However, the present application is not limited to this. For an ordinary person skilled in this field, without deviating from the spirit and essence of the present application, various variants and improvements could be made, which are also regarded as the protection scope of the invention.
[0041] For the sake of simplicity, the present application only explicitly discloses some numerical ranges. However, any lower limit could be combined with any upper limit to form an unspecified range; and any lower limit could be combined with other lower limit to form an unspecified range. Similarly, any upper limit could be combined with any other upper limit to form an unspecified range. In addition, although not explicitly recorded, each point or single value between the range endpoints is included in the range, unless otherwise specified. Therefore, each point or single value could serve as its own lower or upper limit, and could be combined with any other point, single value, or other lower or upper limit to form an unspecified range.
[0042] Compared to the traditional red phosphors, K.sub.2SiF.sub.6:Mn.sup.4+ red phosphor has the advantage of high luminous efficiency, but its poor moisture resistance may readily cause performance degradation, thereby influencing its application effect in LED lighting. The red phosphor in the related art, while enhancing its moisture resistance, would inevitably suffer from a negative impact on its luminous efficiency. Therefore, there is an urgent need for a red phosphor that combines high moisture resistance with high luminous efficiency.
[0043] In order to solve the above problems, the present application provides an anti-deterioration red phosphor. the core-shell structure includes an inner core and an outer shell, the inner core and the outer shell are independently selected from substances shown in a chemical formula I; the chemical formula I: A.sub.2M.sub.(1-x)F.sub.6:xMn.sup.4+. In the chemical formula I, the A includes at least one of Li, Na, K, Rb and Cs, and the M includes at least one of Si, Ge and Ti. An atom percentage of Mn.sup.4+ in an innermost layer of the inner core is a, the atom percentage of Mn.sup.4+ in an outermost layer of the inner core is b, and b>a. The atom percentage of Mn.sup.4+ in each place inside a particle of the inner core is X.sub.1, and a value range of the x.sub.1 is the ax.sub.1b. The atom percentage of Mn.sup.4+ in the outer shell is x.sub.2, and a value range of the x.sub.2 is 0x.sub.20.1%.
[0044] For example, in the chemical formula I, 0<x0.05.
[0045] In some embodiments, the x.sub.1 is in an increasing trend from the inside to the outside in a radial direction of the inner core. In the present application, the radial direction of the inner core from the inside to the outside, refers to a direction from an innermost layer of the inner core to a point on an outermost layer of the kernel closest to the innermost layer of the inner core. The innermost layer of the inner core is a first layer of the inner core, which is formed firstly in the preparation of the anti-deterioration red phosphor. That is, the first layer of the inner core is formed by a reaction between a base liquid A solution and a BX solution first added. In a particle of the phosphor of the present application, an innermost region of the inner core is a region with the lowest activator concentration.
[0046] In some specific embodiments, the inner core is divided into n layers from the inside to the outside along the radial direction, and the n is an integer and a value range of the n is 5n20. An atom percentage of Mn.sup.4+ in a same layer is the same, and the atom percentages of Mn+in different layers increase from the inside to the outside along the radial direction of the inner core.
[0047] In some specific embodiments, a lower limit of the n is selected from any one value in 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18 and 19, and an upper limit of the n is selected from any one value in 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 and 20. A value range of the n is a range formed by any one value of the lower limit and any one value of the upper limit.
[0048] In some specific embodiments, the increasing trend is that the x.sub.1 increases linearly or nonlinearly from the inside to the outside in the radial direction of the inner core.
[0049] In some specific implementations, the increasing trend is that the x.sub.1 increases linearly and uniformly from the inside to the outside in the radial direction of the inner core. In the present application, increasing linearly and uniformly means that the atom percentages of Mn.sup.4+ from the inside to the outside of the inner core maintain a same linear growth trend in the radial direction of the inner core. For example,
[0050] The present application also provides a preparation method of the anti-deterioration red phosphor, for preparing any one of the above anti-deterioration red phosphors, and the preparation method includes following steps: (1) dissolving a salt of the A in a hydrofluoric acid solution, denoted as a base liquid A solution; (2) preparing a series of BX solutions with different concentrations of K.sub.2MnF.sub.6 by taking a series of the K.sub.2MnF.sub.6 and dissolving the series of the K.sub.2MnF.sub.6 in equal masses of H.sub.2MF.sub.6 solutions; and (3) adding the series of the BX solutions into the base liquid A solution in turn, controlling a concentration of the K.sub.2MnF.sub.6 in the BX solution added for a first time is the lowest, and controlling the concentration of K.sub.2MnF.sub.6 in the BX solution added for a last time is the highest, and obtaining an inner core mixed system to prepare the inner core; and adding the H.sub.2MF.sub.6 solution into the inner core mixed system to prepare the outer shell to obtain the anti-deterioration red phosphor. The salt of the A is selected from at least one of a fluoride, a hydrogen fluoride salt, a sulfate, a nitrate, a sulfuric acid hydrogen salt, a carbonate, and a bicarbonate of the A, and the A is selected from any one of Li, Na, K, Rb and Cs. Besides, in the K.sub.2MF.sub.6, the M is selected from any one of Si, Ge and Ti.
[0051] In some exemplary embodiments, fluoride of the A could be selected from any one of lithium fluoride, sodium fluoride, potassium fluoride, rubidium fluoride and cesium fluoride. The hydrogen fluoride salt of the A could be selected from any one of LiHF.sub.2, NaHF.sub.2, KHF.sub.2, RbHF.sub.2 and CsHF.sub.2. Sulfate of the A could be selected from any one of Li.sub.2SO.sub.4, Na.sub.2SO.sub.4, K.sub.2SO.sub.4, Rb.sub.2SO.sub.4 and Cs.sub.2SO.sub.4. Nitrate of the A could be selected from any one of LiNO.sub.3, NaNO.sub.3, KNO.sub.3, RbNO.sub.3 and CsNO.sub.3. Bisulfate of the A could be selected from any one of LiHSO.sub.4, NaHSO.sub.4, KHSO.sub.4, RbHSO.sub.4 and CsHSO.sub.4. The carbonate of A could be selected from any one of Li2CO3, Na2CO3, K.sub.2CO.sub.3, Rb.sub.2CO.sub.3 and Cs.sub.2CO.sub.3. Bicarbonate of the A could be selected from any one of LiHCO.sub.3, NaHCO.sub.3, KHCO.sub.3, RbHCO.sub.3 and CsHCO.sub.3.
[0052] In some exemplary embodiments, the H.sub.2MF.sub.6 could be selected from any of H.sub.2SiF.sub.6, H.sub.2GeF.sub.6 and H.sub.2 TiF.sub.6.
[0053] In some embodiments, in step (3), the process of adding the series of the BX solutions into the base liquid A solution in turn is adding the series of the BX solutions into the base liquid A solution in an order of increasing concentrations of the K.sub.2MnF.sub.6 in turn.
[0054] In some specific embodiments, in step (2), the process of taking a series of the K.sub.2MnF.sub.6 is taking raw materials of the K.sub.2MnF.sub.6, whose masses are a.sub.1, a.sub.2, a.sub.3, . . . , an respectively. Values of a.sub.1, a.sub.2, a.sub.3, . . . , an are in an increasing trend in sequence, and the n is an integer with a range of 5n20.
[0055] In some specific embodiments, a range of the n is 10n20.
[0056] In some specific embodiments, taking and dissolving the raw materials of the K.sub.2MnF.sub.6 whose masses are a.sub.1, a.sub.2, a.sub.3, . . . , an into the H.sub.2MF.sub.6 solution respectively, in order to prepare the series of the BX solutions with increasing concentrations of K.sub.2MnF.sub.6, denoted as BX.sub.1, BX.sub.2, BX.sub.3, . . . , BX.sub.n in sequence. The concentrations of K.sub.2MnF.sub.6 in the BX.sub.1, BX.sub.2, BX.sub.3, . . . , BX.sub.n solutions are in an increasing trend in sequence.
[0057] In some specific embodiments, a value range of the a.sub.1 is 0a.sub.10.01 g. When the al is 0, it means that the masses of K.sub.2MnF.sub.6 increases from 0, and the concentration of K.sub.2MnF.sub.6 of the BX.sub.1 solution in the series of BX solutions prepared is 0.
[0058] In some specific embodiments, the process of adding the series of the BX solutions into the base liquid A solution in turn in an increasing order of the concentrations is adding the BX.sub.1-BX.sub.n solutions into the base liquid A solution in sequence. The inner core is prepared through a series of reactions that occur in turn. The inner core is divided into n layers from the inside to the outside along the radial direction. Each time the BX solution is added, it reacts with the base liquid A solution to form a layer of the inner core.
[0059] In some specific embodiments, in step (3), the mass of H.sub.2MF.sub.6 in the BX solution added each time is the same as the mass of H.sub.2MF.sub.6 in the H.sub.2MF.sub.6 solution. The number of times for adding H.sub.2MF.sub.6 solution to the inner core mixed system is 1-5 times.
[0060] In some specific embodiments, a value range of the a.sub.n is 2.5 ga.sub.n<3 g.
[0061] In some specific embodiments, a mass concentration of the H.sub.2MF.sub.6 solution is 10-15%. The mass of the H.sub.2MF.sub.6 solution is 40-60 g. For example, the mass of the H.sub.2MF.sub.6 solution is 50 g. In some specific embodiments, mass of the salt of the A is 15-25 g.
[0062] In some specific embodiments, a mass concentration of the hydrofluoric acid solution is 35-55%; and a volume of the hydrofluoric acid solution is 200-300 mL. For example, the volume of the hydrofluoric acid solution is 250 mL.
[0063] In some specific embodiments, the process of the washing involves sequentially adding an aqueous solution of HF and anhydrous ethanol, followed by stirring and washing. Besides, a mass concentration of the aqueous solution of HF is 3-10%.
[0064] In some specific embodiments, the process of the drying is drying performed at 50-70 C.
EMBODIMENTS
[0065] In the following, the technical solutions of the present application are explained in combination with the specific embodiments. The raw materials used in the following embodiments are all from ordinary commercially available products, and the devices or equipment used are all purchased from conventional market sales channels.
Embodiment 1
[0066] In the present embodiment, the anti-deterioration red phosphor includes a core-shell structure, the core-shell structure includes an inner core and an outer shell, the inner core and the outer shell are independently selected from substances shown in a chemical formula I; the chemical formula I: K.sub.2Si.sub.(1-x)F.sub.6:xMn.sub.4. The atom percentage of Mn.sup.4+ in each place inside a particle of the inner core is x.sub.1. The X.sub.1 increases linearly and uniformly from the inside to the outside in the radial direction of the inner core, and a value range of the x.sub.1 is 0x.sub.10.77%. Besides, the atom percentage of Mn.sup.4+ in the outer shell is x.sub.2, and a value range of the x.sub.2 is 0x.sub.2<0.1%. What's more, an average particle size of the anti-deterioration red phosphor in the present embodiment is 30 m, where an average thickness of the outer shell is 1.8 m.
[0067] The preparation method for the anti-deterioration red phosphor in the present embodiment includes the following steps:
[0068] (1) dissolving 21 g KHF.sub.2 in 250 mL hydrofluoric acid solution with a mass fraction of 40%, then preparing a base liquid A solution;
[0069] (2) taking a series of the K.sub.2MnF.sub.6, dissolving the series of the K.sub.2MnF.sub.6 in 50 g fluorosilicic acid solution with a mass fraction of 10% according to an order of masses increasing respectively, and preparing a series of BX solutions with increasing concentration of the K.sub.2MnF.sub.6; and
[0070] (3) adding the series of the BX solutions to the base liquid A solution according to an order of concentrations increasing, and obtaining an inner core mixed system for preparing the inner core, wherein adding times are recorded as A.sub.1, A.sub.2, A.sub.3, . . . , A.sub.16; then adding 50 g of fluorosilicic acid solution with a mass fraction of 10% to the inner core mixed system for three times in sequence, in order to prepare an outer shell (masses of the K.sub.2MnF.sub.6 raw materials contained in A1-A19 is shown in Table 1), where adding times are recorded as A.sub.17, A.sub.18 and A.sub.19. During the adding process, stirring the series of the BX solutions and the fluorosilicic acid solution at 40 C., pouring out supernatant after stirring for 2 h, adding a HF aqueous solution with a mass fraction of 5% for stirring and washing twice, then washing twice with anhydrous ethanol, and drying at 60 C. under a blast drying condition to obtain the anti-deterioration red phosphor for the present application.
Embodiment 2
[0071] In the present embodiment, the anti-deterioration red phosphor includes a core-shell structure, the core-shell structure includes an inner core and an outer shell, and the inner core and the outer shell are independently selected from substances shown in a chemical formula I. The chemical formula I: K.sub.2Si.sub.(1-x)F.sub.6:xMn.sup.4+, where the atom percentage of Mn.sup.4+ in each place inside a particle of the inner core is x.sub.1. The x.sub.1 increases from the inside to the outside in the radial direction of the inner core, and a value range of the x.sub.1 is the 0x.sub.10.80%. The atom percentage of Mn.sup.4+ in the outer shell is x.sub.2, and a value range of the x.sub.2 is 0x.sub.20.01%. What's more, an average particle size of the anti-deterioration red phosphor in the present embodiment is 30 m, where an average thickness of the outer shell is 1.8 m.
[0072] The preparation method of the anti-deterioration red phosphor in this embodiment differs from that in the Embodiment 1 only in that: in step (2), K.sub.2MnF.sub.6 raw materials with masses increasing are taken to prepare the series of the BX solutions, and in step (3), masses of the K.sub.2MnF.sub.6 raw materials contained in the added series of the BX solutions are shown in the Table 1.
Embodiment 3
[0073] In the present embodiment, the anti-deterioration red phosphor includes a core-shell structure, the core-shell structure includes an inner core and an outer shell, and the inner core and the outer shell are independently selected from substances shown in a chemical formula I. The chemical formula I: K.sub.2Si.sub.(1-x)F.sub.6:xMn.sub.4, where the atom percentage of Mn.sup.4+ in each place inside a particle of the inner core is X.sub.1. The X.sub.1 increases from the inside to the outside in the radial direction of the inner core, and a value range of the x.sub.1 is 0x.sub.10.82%. The atom percentage of Mn.sup.4+ in the outer shell is x.sub.2, and a value range of the x.sub.2 is 0x.sub.20.02%. What's more, an average particle size of the anti-deterioration red phosphor in the present embodiment is 30 m, where an average thickness of the outer shell is 1.8 m.
[0074] The preparation method of the anti-deterioration red phosphor in this embodiment differs from that in the Embodiment 1 only in that: in step (2), K.sub.2MnF.sub.6 raw materials with masses increasing are taken to prepare the series of the BX solutions, and in step (3), masses of the K.sub.2MnF.sub.6 raw materials contained in the series of the BX solutions added are shown in the Table 1.
Embodiment 4
[0075] In the present embodiment, the anti-deterioration red phosphor includes a core-shell structure, the core-shell structure includes an inner core and an outer shell, and the inner core and the outer shell are independently selected from substances shown in a chemical formula I. The chemical formula I: K.sub.2Si.sub.(1-x)F.sub.6:xMn.sup.4+, where the atom percentage of Mn.sup.4+ in each place inside a particle of the inner core is x.sub.1. The x.sub.1 increases from the inside to the outside in the radial direction of the inner core, and a value range of the x.sub.1 is 0x.sub.10.79%. The atom percentage of Mn.sup.4+ in the outer shell is x.sub.2, and a value range of the x.sub.2 is 0x.sub.20.01%. What's more, an average particle size of the anti-deterioration red phosphor in the present embodiment is 30 m, where an average thickness of the outer shell is 1.8 m.
[0076] The preparation method of the anti-deterioration red phosphor in this embodiment differs from that in the Embodiment 1 only in that: in step (2), K.sub.2MnF.sub.6 raw materials with masses increasing are taken to prepare the series of the BX solutions, and in step (3), masses of the K.sub.2MnF.sub.6 raw materials contained in the series of the BX solutions added are shown in the Table 1.
Embodiment 5
[0077] In the present embodiment, the anti-deterioration red phosphor includes a core-shell structure, the core-shell structure includes an inner core and an outer shell, and the inner core and the outer shell are independently selected from substances shown in a chemical formula I. The chemical formula I: K.sub.2Si.sub.(1-x)F.sub.6:xMn.sup.4+, where the atom percentage of Mn.sup.4+ in each place inside a particle of the inner core is x.sub.1. The x.sub.1 increases from the inside to the outside in the radial direction of the inner core, and a value range of the x.sub.1 is the 0x.sub.10.81%. The atom percentage of Mn+in the outer shell is x.sub.2, and a value range of the x.sub.2 is 0x.sub.20.02%. What's more, an average particle size of the anti-deterioration red phosphor in the present embodiment is 30 m, where an average thickness of the outer shell is 1.8 m.
[0078] The preparation method of the anti-deterioration red phosphor in this embodiment differs from that in the Embodiment 1 only in that: in step (2), K.sub.2MnF.sub.6 raw materials with masses increasing are taken to prepare the series of the BX solutions, and in step (3), masses of the K.sub.2MnF.sub.6 raw materials contained in the series of the BX solutions added are shown in the Table 1.
Embodiment 6
[0079] In the present embodiment, the anti-deterioration red phosphor includes a core-shell structure, the core-shell structure includes an inner core and an outer shell, and the inner core and the outer shell are independently selected from substances shown in a chemical formula I. The chemical formula I: K.sub.2Si.sub.(1-x)F.sub.6:xMn.sup.4+, where the atom percentage of Mn.sup.4+ in an innermost layer of the inner core of the phosphor is 0, the atom percentage of Mn.sup.4+ in an outermost layer of the inner core of the phosphor is 0.77%, and the atom percentage of Mn.sup.4+ in each place of the inner core of the phosphor is x.sub.1. Besides, in addition to the innermost layer and the outermost layer of the inner core, the x.sub.1 is randomly distributed from the inside to the outside in the radial direction of the inner core, and a value range of the x.sub.1 is 0x.sub.10.77%. Besides, the atom percentage of Mn.sup.4+ in the outer shell is x.sub.2, and a value range of the x.sub.2 is 0x.sub.20.01%. What's more, an average particle size of the anti-deterioration red phosphor in the present embodiment is 30 m, where an average thickness of the outer shell is 1.8 m.
[0080] The preparation method of the anti-deterioration red phosphor in this embodiment differs from that in the Embodiment 1 only in that: in step (2), K.sub.2MnF.sub.6 raw materials are taken to prepare the series of the BX solutions, and in step (3), masses of the K.sub.2MnF.sub.6 raw materials contained in the series of the BX solutions added are shown in the Table 1.
Embodiment 7
[0081] In the present embodiment, the anti-deterioration red phosphor includes a core-shell structure, the core-shell structure includes an inner core and an outer shell, and the inner core and the outer shell are independently selected from substances shown in a chemical formula I. The chemical formula I: K.sub.2Si.sub.(1-x)F.sub.6:xMn.sup.4+, where the atom percentage of Mn.sup.4+ in an innermost layer of the inner core of the phosphor is 0, the atom percentage of Mn.sup.4+ in an outermost layer of the inner core of the phosphor is 5%, and the atom percentage of Mn.sup.4+ in each place of the inner core of the phosphor is x.sub.1. The x.sub.1 increases linearly and uniformly from the inside to the outside in the radial direction of the inner core, and a value range of the x.sub.1 is the 0x.sub.15%; and the atom percentage of Mn.sup.4+ in the outer shell is x.sub.2, and a value range of the x.sub.2 is 0x.sub.20.1%.
Embodiment 8
[0082] In the present embodiment, the anti-deterioration red phosphor includes a core-shell structure, the core-shell structure includes an inner core and an outer shell, and the inner core and the outer shell are independently selected from substances shown in a chemical formula I. The chemical formula I: K.sub.2Si.sub.(1-x)F.sub.6:xMn.sup.4+, where the atom percentage of Mn.sup.4+ in an innermost layer of the inner core of the phosphor is 0.1%, and the atom percentage of Mn.sup.4+ in an outermost layer of the inner core of the phosphor is 0.3%. The atom percentage of Mn.sup.4+ in each place of the inner core of the phosphor is x.sub.1, the x.sub.1 increases linearly and uniformly from the inside to the outside in the radial direction of the inner core, and a value range of the x.sub.1 is the 0.1%x.sub.10.3%. The atom percentage of Mn.sup.4+ in the outer shell is x.sub.2, and a value range of the x.sub.2 is 0x.sub.20.01%.
Embodiment 9
[0083] In the present embodiment, the anti-deterioration red phosphor includes a core-shell structure, the core-shell structure includes an inner core and an outer shell, and the inner core and the outer shell are independently selected from substances shown in a chemical formula I. The chemical formula I: K.sub.2Si.sub.(1-x)F.sub.6:xMn.sup.4+, where the atom percentage of Mn.sup.4+ in an innermost layer of the inner core of the phosphor is 0, the atom percentage of Mn.sup.4+ in an outermost layer of the inner core of the phosphor is 2%, and the atom percentage of Mn.sup.4+ in each place of the inner core of the phosphor is x.sub.1. The x.sub.1 increases linearly and uniformly from the inside to the outside in the radial direction of the inner core, and a value range of the x.sub.1 is the 0x.sub.12%. The atom percentage of Mn.sup.4+ in the outer shell is x.sub.2, and a value range of the x.sub.2 is 0x.sub.20.05%.
Embodiment 10
[0084] In the present embodiment, the anti-deterioration red phosphor includes a core-shell structure, the core-shell structure includes an inner core and an outer shell, and the inner core and the outer shell are independently selected from substances shown in a chemical formula I. The chemical formula I: K.sub.2Si.sub.(1-x)F.sub.6:xMn.sup.4+, where the atom percentage of Mn.sup.4+ in an innermost layer of the inner core of the phosphor is 0, the atom percentage of Mn.sup.4+ in an outermost layer of the inner core of the phosphor is 0.5%, and the atom percentage of Mn.sup.4+ in each place of the inner core of the phosphor is x.sub.1. The x.sub.1 increases linearly and uniformly from the inside to the outside in the radial direction of the inner core, and a value range of the x.sub.1 is 0x.sub.10.5%. The atom percentage of Mn.sup.4+ in the outer shell is x.sub.2, and a value range of the x.sub.2 is 0x.sub.20.01%.
Embodiment 11
[0085] In the present embodiment, the anti-deterioration red phosphor includes a core-shell structure, the core-shell structure includes an inner core and an outer shell, the inner core and the outer shell are independently selected from substances shown in a chemical formula I. The chemical formula I: Li.sub.2Si.sub.(1-x)F.sub.6:xMn.sup.4+, where the atom percentage of Mn.sup.4+ in each place inside a particle of the inner core is x.sub.1, the x.sub.1increases linearly and uniformly from the inside to the outside in the radial direction of the inner core, and a value range of the x.sub.1 is the 0x.sub.10.81%; and the atom percentage of Mn.sup.4+ in the outer shell is x.sub.2, and a value range of the x.sub.2 is 0x.sub.20.01%. An average particle size of the anti-deterioration red phosphor in the present embodiment is 30 m, where an average thickness of the outer shell is 1.8 m.
[0086] The preparation method of the anti-deterioration red phosphor in this embodiment differs from that in the Embodiment 1 only in that: in step (1), Li.sub.2CO.sub.3 is used as a substitute for KHF.sub.2 to dissolve into the hydrofluoric acid solution.
Embodiment 12
[0087] In the present embodiment, the anti-deterioration red phosphor includes a core-shell structure, the core-shell structure includes an inner core and an outer shell, and the inner core and the outer shell are independently selected from substances shown in a chemical formula I. The chemical formula I: Cs.sub.2Si.sub.(1-x)F.sub.6:xMn.sup.4+, where the atom percentage of Mn.sup.4+ in each place inside a particle of the inner core is x.sub.1, the x.sub.1 increases linearly and uniformly from the inside to the outside in the radial direction of the inner core, and a value range of the x.sub.1 is 0x.sub.10.80%. The atom percentage of Mn.sup.4+ in the outer shell is x.sub.2, and a value range of the x.sub.2 is 0x.sub.20.01%. What's more, an average particle size of the anti-deterioration red phosphor in the present embodiment is 30 m, where an average thickness of the outer shell is 1.8 m.
[0088] The preparation method of the anti-deterioration red phosphor in this embodiment differs from that in the Embodiment 1 only in that: in step (1), CsF is used a substitute for KHF.sub.2 to dissolve into the hydrofluoric acid solution.
Embodiment 13
[0089] In the present embodiment, the anti-deterioration red phosphor includes a core-shell structure, the core-shell structure includes an inner core and an outer shell, and the inner core and the outer shell are independently selected from substances shown in a chemical formula I. The chemical formula I: K.sub.2Ge.sub.(1-x)F.sub.6:xMn.sup.4+, where the atom percentage of Mn.sup.4+ in each place inside a particle of the inner core is x.sub.1, the x.sub.1 increases linearly and uniformly from the inside to the outside in the radial direction of the inner core, and a value range of the x.sub.1 is the 0x.sub.10.82%. The atom percentage of Mn.sup.4+ in the outer shell is x.sub.2, and a value range of the x.sub.2 is 0x.sub.20.01%. An average particle size of the anti-deterioration red phosphor in the present embodiment is 30 m, where an average thickness of the outer shell is 1.8 m.
[0090] The preparation method of the anti-deterioration red phosphor in this embodiment differs from that in the Embodiment 1 only in that: in step (2) and step (3), a H.sub.2GeF.sub.6 solution is used a substitute for the fluorosilicic acid solution.
Embodiment 14
[0091] In the present embodiment, the anti-deterioration red phosphor includes a core-shell structure, the core-shell structure includes an inner core and an outer shell, and the inner core and the outer shell are independently selected from substances shown in a chemical formula I. The chemical formula I: K.sub.2Ti.sub.(1-x)F.sub.6:xMn.sup.4+, where the atom percentage of Mn.sup.4+ in each place inside a particle of the inner core is x.sub.1, the x.sub.1 increases linearly and uniformly from the inside to the outside in the radial direction of the inner core, and a value range of the x.sub.1 is the 0x.sub.10.81%. The atom percentage of Mn.sup.4+ in the outer shell is x.sub.2, and a value range of the x.sub.2 is 0x.sub.2<0.01%. An average particle size of the anti-deterioration red phosphor in the present embodiment is 30 m, where an average thickness of the outer shell is 1.8 m.
[0092] The preparation method of the anti-deterioration red phosphor in this embodiment differs from that in the Embodiment 1 only in that: in step (2) and step (3), a H.sub.2TiF.sub.6 solution is used as a substitute for the fluorosilicic acid solution.
Comparison 1
[0093] The phosphor in this comparison differs from that in the Embodiment 1 only in that: the present comparison only includes the inner core of the anti-deterioration red phosphor from the Embodiment 1, excluding its outer shell.
[0094] The preparation method of the phosphor in this comparison differs from that in the Embodiment 6 is only in that: in step (3), adding the series of the BX solutions to the base liquid A solution in an order of concentrations increasing, where adding times are recorded as A.sub.1, A.sub.2, A.sub.3, . . . , A.sub.16, and the masses of the K.sub.2MnF.sub.6 raw materials contained in A.sub.1-A.sub.16 are shown in table 1 below, which is identical to the masses of the K.sub.2MnF.sub.6 raw materials corresponding to A.sub.1-A.sub.16 in step (3) of the Embodiment 1. After adding the BX solution, the fluorosilicic acid solution is no longer added.
Comparison 2
[0095] The phosphor in this comparison differs from that in the Embodiment 1 only in that: the atom percentage of Mn.sup.4+ at each place within the particle in the inner core of the phosphor is x.sub.1, and the x.sub.1 exhibits a uniform distribution from the inside to the outside in the radial direction.
[0096] The preparation method of the phosphor in this comparison differs from that in the Embodiment 1 is only in that: in step (2), a series of the BX solutions with the same concentration of the K.sub.2MnF.sub.6 are prepared by respectively dissolving 16 equal parts of the K.sub.2MnF.sub.6 raw materials into 50 g of 10% fluosilicic acid solution, with each part containing 1.35 g of K.sub.2MnF.sub.6; and in step (3), the series of the BX solutions are added to the base liquid A solution, and the adding times are recorded as A.sub.1, A.sub.2, A.sub.3, . . . , A.sub.16, These additions are used to prepare an inner core with a uniform distribution of the atom percentage of Mn.sup.4+. The preparation of the outer shell is the same as that in the Embodiment 1.
Comparison 3
[0097] The phosphor in this comparison differs from that in the Comparison 2 only in that: the present comparison only includes the inner core of the phosphor from the Comparison 2, excluding its outer shell.
[0098] The preparation method of the phosphor in this comparison differs from that in the Comparison 2 is only in that: : in step (3), after adding the series of the BX solutions to the base liquid A solution, the fluorosilicic acid solution is no longer added.
[0099] Table 1 shows the masses of the K.sub.2MnF.sub.6 in the series of the BX solutions and the fluosilicic acid solution added during step (3) of the Comparison 1 and the Embodiments 1-6.
TABLE-US-00001 TABLE 1 Adding Embodiment Embodiment Embodiment Embodiment Embodiment Embodiment Comparison time 1 2 3 4 5 6 1 A1 0 0 0 0 0 0 0 A2 0.18 0.03 0.02 0.52 0.89 1.44 0.18 A3 0.36 0.07 0.04 0.86 1.32 2.34 0.36 A4 0.54 0.15 0.08 1.16 1.58 1.62 0.54 A5 0.72 0.22 0.12 1.38 1.81 1.26 0.72 A6 0.90 0.34 0.17 1.57 2.05 0.36 0.90 A7 1.08 0.46 0.23 1.76 2.25 0.72 1.08 A8 1.26 0.59 0.30 1.91 2.40 1.08 1.26 A9 1.44 0.74 0.39 2.07 2.51 1.80 1.44 A10 1.62 0.95 0.48 2.24 2.58 2.16 1.62 A11 1.80 1.14 0.61 2.37 2.63 1.98 1.80 A12 1.98 1.34 0.79 2.43 2.66 0.18 1.98 A13 2.16 1.57 1.00 2.52 2.68 2.52 2.16 A14 2.34 1.87 1.27 2.60 2.68 0.90 2.34 A15 2.52 2.23 1.77 2.65 2.69 0.54 2.52 A16 2.70 2.70 2.70 2.70 2.70 2.70 2.70 A17 0 0 0 0 0 0 / A18 0 0 0 0 0 0 / A19 0 0 0 0 0 0 /
[0100] From the Table 1, it could be seen that the Embodiments 1-5 prepare the series of BX solutions using the K.sub.2MnF.sub.6 raw materials with a gradually increasing trend in masses for the preparation for the inner core. The masses of the K.sub.2MnF.sub.6 raw materials used in the preparation of the inner core in the Embodiment 1 are increased in a form of an arithmetic progression, and the tolerance is 0.18 g. The increasing trend of the Embodiments 2-5 is non-linear. In the preparation of the inner core, only the masses of K.sub.2MnF.sub.6 raw materials contained in the BX solutions, added both initially and finally, are controlled to be a minimum of 0 g and a maximum of 2.70 g, respectively. For the remaining adding times, the masses of K.sub.2MnF.sub.6 raw material are arranged randomly. The mass of the K.sub.2MnF.sub.6 raw material used to prepare the inner core of the Comparison 1 is the same as that of the Embodiment 1, but the outer shell is not prepared.
Test Embodiment 1
[0101] Focused ion beam scanning electron microscope (FIB-SEM) equipment is used to cut the anti-deterioration red phosphor of the Embodiment 1-5 by dual ion beam. EDS energy spectrum analysis is performed from the body center to the surface on the fresh surface. Taking the Embodiment 1 as an example,
TABLE-US-00002 TABLE 2 Radial distribution of Mn atom percentage in the Embodiments 1 to 5 Atom percentage Embodi- Embodi- Embodi- Embodi- Embodi- % ment 1 ment 2 ment 3 ment 4 ment 5 Ato % 0.00 0.00 0.00 0.00 0.00 0.04 0.01 0.01 0.15 0.23 0.10 0.04 0.01 0.26 0.38 0.19 0.05 0.03 0.37 0.48 0.22 0.07 0.05 0.41 0.53 0.25 0.11 0.05 0.48 0.61 0.32 0.15 0.06 0.52 0.64 0.37 0.17 0.08 0.56 0.71 0.46 0.22 0.13 0.63 0.74 0.44 0.27 0.16 0.67 0.75 0.53 0.34 0.18 0.72 0.79 0.62 0.42 0.24 0.75 0.79 0.67 0.47 0.31 0.75 0.80 0.65 0.58 0.37 0.74 0.81 0.73 0.65 0.53 0.77 0.80 0.77 0.80 0.82 0.79 0.81 0.01 0.01 0.01 0.01 0.01 0.01 0.00 0.02 0.00 0.01 0.00 0.00 0.00 0.01 0.02
[0102] Based on the Table 2, the anti-deterioration red phosphor from each of Embodiments 1-5 is radially divided into 16 layers from the innermost part to the outermost part of the inner core, while the outer shell is radially divided into 3 layers from the inside out. The percentage of Mn atoms exhibits an increasing trend radially from the innermost layer to the outermost layer of the inner core. Despite some individual values being equal to or slightly lower than previous ones, this does not affect the overall increasing trend of Mn atom percentage along the radial direction of the inner core. Notably, the innermost layer of the inner core does not contain Mn atom, with a Mn atom percentage of 0%, and Mn atom percentage at the outermost layer of the inner core is 0.77%-0.82%. In the outer shell, Mn atom percentage is between 0% and 0.02%. Among them, Mn atom percentage in Embodiment 1 shows an overall linear and uniform increase along the radial direction of the inner core.
[0103] To visually reflect the increasing trend of Mn content in Embodiments 1-5, a schematic diagram of the radial distribution of relative content of Mn.sup.4+ within the particle of the anti-deterioration red phosphor for each of Embodiments 1-5 is shown in
[0104] The surface of the particle of the phosphor is tested by EDX from the body center to the surface using the focused ion beam scanning electron microscope (FIB-SEM) equipment. The surface of the particle of the phosphor is the surface corresponding to the particle of the anti-deterioration red phosphor after cutting in the Embodiment 5. The EDX line scan positions are illustrated in
Test Embodiment 2
[0105] Aging tests are performed on the phosphors in the Embodiments 1-6 and Comparisons 1-3, measuring the luminous flux of each embodiment or comparison at 0, 250, 500, 750, and 1000 hours, respectively. Table 3 presents the test methods and equipment used for the 1000-hour aging test in the present application. Table 4 displays the aging test data for the KSF phosphors prepared in the embodiments and comparisons. (Note: KSF-0 represents the sample from the Comparison 1, KSF-1 represents the sample from the Embodiment 1, KSF-2 represents the sample from the Embodiment 2, KSF-3 represents the sample from the Embodiment 3, KSF-4 represents the sample from the Embodiment 4, KSF-5 represents the sample from the Embodiment 5, KSF-6 represents the sample from the Embodiment 6, KSF-7 represents the sample from Comparison 2, and KSF-8 represents the sample from Comparison 3).
TABLE-US-00003 TABLE 3 test methods and equipments of the Embodiments 1-6 and aging test of Comparisons 1-3. Model Manufacture Bracket Ageing Test number scheme type Chip Current conditioning machine KSF-X Positive white SMD- 22*25 mil 65 mA Temperature: EVERFINE (X = 0, color temperature 2835 Double 85 C. HAAS2000 1, 2, 3, full spectrum wafer Humidity: 4, 5, 6, parallel 85 RH % 7, 8) connection
TABLE-US-00004 TABLE 4 the results of luminous flux and brightness ratio in the Embodiments 1-6 and Comparisons 1-3 during the aging tests. Testing time (h) Parameter 0 250 500 750 1000 KSF-0 Luminous 128.35 127.58 126.93 125.14 123.47 flux(lm) KSF-0 Brightness 100% 99.4% 98.9% 97.5% 96.2% ratio(%) KSF-1 Luminous 128.21 127.95 127.44 125.18 127.05 flux(lm) KSF-1 Brightness 100% 99.8% 99.4% 99.2% 99.2% ratio(%) KSF-2 Luminous 128.15 127.89 127.50 127.12 126.86 flux(lm) KSF-2 Brightness 100% 99.8% 99.5% 99.2% 99.0% ratio(%) KSF-3 Luminous 128.17 128.04 127.40 127.27 127.01 flux(lm) KSF-3 Brightness 100% 99.9% 99.4% 99.3% 99.1% ratio(%) KSF-4 Luminous 128.02 127.37 126.99 126.86 126.61 flux(lm) KSF-4 Brightness 100% 99.5% 99.2% 99.1% 98.9% ratio(%) KSF-5 Luminous 128.14 127.37 127.11 126.98 126.85 flux(lm) KSF-5 Brightness 100% 99.4% 99.2% 99.1% 99.0% ratio(%) KSF-6 Luminous 126.34 125.97 125.47 125.22 125.10 flux(lm) KSF-6 Brightness 100% 99.7% 99.3% 99.1% 99.0% ratio(%) KSF-7 Luminous 117.48 117.13 116.89 116.66 116.07 flux(lm) KSF-7 Brightness 100% 99.7% 99.5% 99.3% 98.8% ratio(%) KSF-8 Luminous 120.83 119.98 119.14 117.57 116.12 flux(lm) KSF-8 Brightness 100% 99.3% 98.6% 97.3% 96.1% ratio(%)
[0106] As shown in Table 4, the LED devices fabricated using the phosphors from the Embodiments 1-6 and the Comparison 1, under conditions of 85 C. and 85% RH, exhibit an initial luminous flux ranging from 126.34 lm to 128.35 lm. In contrast, the LED device using the phosphor from the Comparison 2 has an initial luminous flux of only 117.48 lm, while the corresponding Comparison 3 used for comparison, has an initial luminous flux of 120.83 lm. This indicates that the inner core of the Comparison 2 experiences a 2.8% reduction in initial luminous flux after the outer shell added. It is evident that the present application, by controlling the content of Mn in the innermost and outermost layers of the core, and employing an outer shell with a relatively low atom percentage of Mn, does not compromise the luminescent efficiency of the phosphor. Besides, this is conducive to maintaining a high luminescent intensity of the phosphor. As the testing time increases, the luminous flux of the LED device using the phosphor from the Comparison 1 gradually decreases, with a reduction in brightness ratio of approximately 1% every 250 hours. After 1000 hours, the luminous flux drops to only 123.47 lm, and the brightness is only 96.2% of the initial brightness, representing a decrease of 3.8% compared to the initial value. In contrast, the LED devices corresponding to the anti-deterioration red phosphors from the Embodiments 1-6 exhibit a smaller decrease in the luminous flux. After 1,000 hours of testing with a high-temperature and high-humidity environment, the luminous flux remains within a range of 125.10 lm to 127.05 lm, and the brightness still reaches 98.9%-99.2% of the initial brightness, basically maintaining a brightness ratio of 99%. It is evident that by setting an outer shell with very little or no Mn.sup.4+ content to coat the inner core of the phosphor in the present application, the moisture resistance and anti-deterioration ability of the phosphor are significantly enhanced without compromising its luminescent efficiency. Besides, this enables the phosphor to maintain a high luminescent intensity even when operated in harsh environments with long-term exposure to a high temperatures and high humidity.
[0107] Furthermore, a horizontal comparison among the Embodiments 1-5 reveals that the Embodiment 1, which adopts a solution where the atomic percentage of Mn increases linearly and uniformly along the radial direction of the inner core, exhibits the highest measured initial luminous flux of 128.21 lm. Additionally, during the aging test, the Embodiment 1 demonstrates the lowest reduction in luminous flux, with the brightness ratio remaining at 99.2% after 1000 hours, a mere decrease of 1.8%. This indicates that, in the present application, by controlling Mn atom percentage to increase linearly and uniformly along the radial direction of the inner core, the conversion efficiency of the phosphor is ensured. When paired with the outer shell, it experiences minimal impact on its luminous flux from a harsh environment during long-term service, which is conducive to further ensuring a higher luminous efficiency.
Test Embodiment 3
[0108] The phosphor samples from the Embodiments 1, 7 to 10 are encapsulated into the LED chip using the method described in Table 3 of the Test embodiment 2, and the luminous flux of each embodiment sample is tested. The results are shown in Table 5 below.
TABLE-US-00005 TABLE 5 luminous flux results of Samples from the Embodiment 1 and the Embodiments 7-10 Embodiment Embodi- Embodi- Embodi- Embodi- Embodi- number ment 1 ment 7 ment 8 ment 9 ment 10 Luminous 128.21 119.35 120.73 124.20 126.86 flux(lm)
[0109] As shown in the Table 5, the luminous flux of the phosphor samples from the Embodiment 1 and the Embodiments 7-10 ranges from 119.35 to 128.21 lm, demonstrating strong luminescent performance. Among them, the phosphor samples from the Embodiments 1, 9, and 10, which have a difference in activator atom percentage between the outermost and innermost layers of the inner core ranging from 0.5% to 2%, exhibit a luminous flux of 124.20 to 128.21 lm. This is a further improvement compared to the Embodiments 7 and 8. It is evident that by controlling the distribution of Mn.sup.4+ atom percentage within the inner core in the present application, the absorption efficiency of the phosphor is enhanced, leading to more excellent luminescent performance.
[0110] The above description is merely a specific embodiment of the present application, but the protection scope of the present application is not limited to this. Any variations or substitutions, which could be easily conceivable by any technician person skilled in the art within the technical scope disclosed by this application, should be encompassed within the protection scope of this application. Therefore, equivalent variations made according to the claims of the present application still fall within the scope covered by the present application.