Red phosphor, preparation method thereof and light-emitting device prepared therefrom

Abstract

The present invention relates to a red phosphor, a preparation method thereof and a light-emitting device prepared therefrom. A particle of the red phosphor consists of a phosphor inner core having a chemical formula of A.sub.x1Ge.sub.z1F.sub.6:y.sub.1Mn.sup.4+ and an outer shell having a chemical formula of B.sub.x2M.sub.z2F.sub.6:y.sub.2Mn.sup.4+, wherein 1.596≤x.sub.1≤2.2, 1.6≤x.sub.2≤2.2, 0.001≤y.sub.1≤0.2, 0≤y.sub.2≤0.2, 0.9≤z.sub.1≤1.1, and 0.9≤z.sub.2≤1.1; A and B are independently selected from alkali metal elements; and M is Si, or Si and Ge. The red phosphor provided by the present invention has high luminous efficiency and stability. Moreover, the phosphor alone or in combination with other luminescent materials can be used for preparing a light-emitting device with high performance.

Claims

1. A red phosphor, wherein a particle of the red phosphor consists of a phosphor inner core having a chemical formula of A.sub.x1Ge.sub.z1F.sub.6:y.sub.1Mn.sup.4+ and an outer shell having a chemical formula of B.sub.x2M.sub.z2F.sub.6:y.sub.2Mn.sup.4+, wherein 1.596≤x.sub.1≤2.2, 1.6≤x.sub.2≤2.2, 0.1<y.sub.1≤0.2, 0<y.sub.2≤0.2, 0.9≤z.sub.1≤1.1, 0.9≤z.sub.2≤1.1; A and B are independently selected from alkali metal elements; and M is Si and Ge, and a molar ratio m of Si to M in the outer shell meets the following condition: 0.5≤m<1; the outer shell has a thickness of 0.5 μm to 15 μm.

2. The red phosphor according to claim 1, wherein A and B are independently selected from Li, Na and K.

3. The red phosphor according to claim 1, wherein a molar ratio n of Mn to M in the outer shell meets the following condition: 0<n≤0.1.

4. The red phosphor according to claim 3, wherein 0.5≤m<1, and 0<n≤0.05.

5. The red phosphor according to claim 1, wherein the particle size of the red phosphor is 5 μm to 45 μm.

6. The red phosphor according to claim 1, wherein the outer shell has a thickness of 2 μm to 5 μm, and the particle size of the red phosphor is 15 μm to 35 μm.

7. A preparation method of the red phosphor of claim 1, comprising: (1) performing dosing based on A.sub.x1Ge.sub.z1F.sub.6:y.sub.1Mn.sup.4+, separately dissolving compounds that contain A, Ge and Mn in a 30-50 wt % hydrofluoric acid solution at 10° C. to 50° C., performing mixing, and sieving, washing and drying an obtained precipitate to obtain powder of an A.sub.x1Ge.sub.z1F.sub.6:y.sub.1Mn.sup.4+ phosphor inner core; (2) performing dosing based on B.sub.x2M.sub.z2F.sub.6:y.sub.2Mn.sup.4+ wherein M is Si and Ge, separately dissolving compounds that contain A and M, or compounds that contain A, M and Mn in a 30-50 wt % hydrofluoric acid solution at 10° C. to 50° C., and performing mixing to obtain a mother liquid material; and (3) adding the powder of the phosphor inner core obtained in step (1) into the mother liquid material obtained in step (2), performing stirring to obtain a precipitate, and sieving, washing and drying the obtained precipitate to obtain the red phosphor.

8. The preparation method according to claim 7, wherein the stirring in step (3) is performed for 2 minutes to 60 minutes.

9. A light-emitting device, comprising the red phosphor of claim 1.

10. The light-emitting device according to claim 9, further comprising a radiation source, and the radiation source is a semiconductor light-emitting chip, wherein the semiconductor light-emitting chip is an LED chip with an emission peak wavelength of 440 nm to 470 nm.

11. The red phosphor according to claim 2, wherein the particle size of the red phosphor is 5 μm to 45 μm.

12. The red phosphor according to claim 3, wherein the particle size of the red phosphor is 5 μm to 45 μm.

13. The red phosphor according to claim 4, wherein the particle size of the red phosphor is 5 μm to 45 μm.

14. The red phosphor according to claim 2, wherein the outer shell has a thickness of 2 μm to 5 μm, and the particle size of the red phosphor is 15 μm to 35 μm.

15. The red phosphor according to claim 3, wherein the outer shell has a thickness of 2 μm to 5 μm, and the particle size of the red phosphor is 15 μm to 35 μm.

16. The red phosphor according to claim 1, wherein A and B are K.

17. The red phosphor according to claim 1, wherein the outer shell has a thickness of 1 μm to 12 μm; and the particle size of the red phosphor is 10 μm to 40 μm.

18. The red phosphor according to claim 3, wherein the outer shell has a thickness of 1 μm to 12 μm; and the particle size of the red phosphor is 10 μm to 40 μm.

19. The red phosphor according to claim 2, wherein a molar ratio n of Mn to M in the outer shell meets the following condition: 0<n≤0.1.

20. The red phosphor according to claim 16, wherein the particle size of the red phosphor is 5 μm to 45 μm.

Description

DETAILED DESCRIPTION

(1) To facilitate understanding of the present invention, the following embodiments of the present invention are listed. It should be understood by those skilled in the art that these embodiments are only intended to help understand the present invention and by no means are to be construed as any specific limitation on the present invention.

(2) It should be noted that in case of no conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be illustrated in detail below with reference to the embodiments.

(3) It should be noted that the terms used herein are for the purpose of describing specific implementation modes, and are not intended to limit exemplary implementation modes of the present application. As used herein, unless otherwise explicitly pointed out by the context, singular forms are intended to include plural forms. Moreover, it should be understood that when the term “comprising” and/or “including” is used in the description, it is intended to indicate the presence of features, steps, operations, apparatuses, devices, components, and/or combinations thereof.

Comparative Example 1

(4) (1) Dosing is performed based on K.sub.2Ge.sub.0.9F.sub.6:0.1Mn.sup.4+. Compounds that contain K, Ge and Mn are separately dissolved in a 30-50 wt % hydrofluoric acid solution at 10° C. to 50° C. Mixing is performed. An obtained precipitate is sieved, washed and dried to obtain a K.sub.2Ge.sub.0.9F.sub.6:0.1Mn.sup.4+ phosphor.

(5) (2) The red phosphor obtained in the Comparative Example of the present invention and a β-SiAlON:Eu.sup.2+ green phosphor are uniformly dispersed in organic silica gel at a mass ratio of 4:1. A blue-light LED (with an emission wavelength of 450 nm) is coated with a mixture obtained after mixing and defoaming. Drying is performed for 3 hours at 150° C., Then, encapsulation is accomplished to obtain a white-light LED device. 150 mA current is provided to the white-light LED device at the humidity of 85% and the temperature of 85° C. for lightening for 168 hours. Changes of luminous flux of the white-light LED device are tested and the luminous flux decay rate is calculated. The decay rate is obtained by dividing the difference between an initial luminous flux and a luminous flux after 168 hours by the initial luminous flux. The obtained results are listed in Table 1.

Embodiments 1 to 21

(6) (1) Dosing is performed based on K.sub.x1Ge.sub.z1F.sub.6:y.sub.1Mn.sup.4+. Compounds that contain K, Ge and Mn are separately dissolved in a 30-50 wt % hydrofluoric acid solution at 10° C. to 50° C. Mixing is performed. An obtained precipitate is sieved, washed and dried to obtain powder of a K.sub.x1Ge.sub.z1F.sub.6:y.sub.1Mn.sup.4+ phosphor inner core.

(7) (2) Dosing is performed based on K.sub.x2M.sub.z2F.sub.6:y.sub.2Mn.sup.4+, wherein M is Si and Ge, or Si. Compounds that contain A and M, or compounds that contain A, M and Mn are separately dissolved in a 30-50 wt % hydrofluoric acid solution at 10° C. to 50° C. Mixing is performed to obtain a mother liquid material.

(8) (3) The powder of the phosphor inner core obtained in step (1) is added into the mother liquid material obtained in step (2). Stirring is performed to obtain a precipitate. The obtained precipitate is sieved, washed and dried to obtain the red phosphor. Specific compositions of products in Embodiments 1 to 21 are listed in Table 1.

(9) (4) The red phosphor obtained in the Embodiments 1 to 21 of the present invention and a β-SiAlON:Eu.sup.2+ green phosphor are uniformly dispersed in organic silica gel at a mass ratio of 4:1. A blue-light LED (with an emission wavelength of 450 nm) is coated with a mixture obtained after mixing and defoaming. Drying is performed for 3 hours at 150° C. Then, encapsulation is accomplished to obtain a white-light LED device. 150 mA current is provided to the white-light LED device at the humidity of 85% and the temperature of 85° C. for lightening for 168 hours. Changes of luminous flux of the white-light LED device are tested and the luminous flux decay rate is calculated. The decay rate is obtained by dividing the difference between an initial luminous flux and a luminous flux after 168 hours by the initial luminous flux. The obtained results are listed in Table 1.

(10) TABLE-US-00001 TABLE 1 Luminous Flux Decay Rate at the Thickness humidity of Display of Outer Particle Encapsulation 85% and the Color Shell Size Luminous temperature Gamut Chemical Formula (μm) (μm) Flux (%) of 85° C. (%) (% NTSC) Comparative K.sub.2Ge.sub.0.9F.sub.6:0.1 Mn.sup.4+ 0 26 100 5 92 Example 1 Embodiment K.sub.2Ge.sub.0.9F.sub.6:0.1 Mn.sup.4+@ 2 15 108 2 93 1 K.sub.2Si.sub.0.6Ge.sub.0.25F.sub.6:0.05 Mn.sup.4+ Embodiment K.sub.2Ge.sub.0.92F.sub.6:0.08 Mn.sup.4+@ 3 35 105 2.6 94 2 K.sub.1.6Si.sub.0.6Ge.sub.0.48F.sub.6:0.02 Mn.sup.4+ Embodiment K.sub.2Ge.sub.0.89F.sub.6:0.11 Mn.sup.4+@ 2.5 16 109 2.1 95 3 K.sub.1.6Si.sub.0.6Ge.sub.0.48F.sub.6:0.02 Mn.sup.4+ Embodiment K.sub.2Ge.sub.0.82F.sub.6:0.18 Mn.sup.4+@ 4.5 22 104 3.2 93 4 K.sub.1.6Si.sub.0.6Ge.sub.0.48F.sub.6:0.02 Mn.sup.4+ Embodiment K.sub.1.596Ge.sub.1.1F.sub.6:0.001 Mn.sup.4+@ 9 30 103 1.4 93 5 K.sub.2Si.sub.0.48Ge.sub.0.48F.sub.6:0.04 Mn.sup.4+ Embodiment K.sub.1.8Ge.sub.0.99F.sub.6:0.06 Mn.sup.4+@ 5 28 105 1 93 6 K.sub.1.8Si.sub.0.9Ge.sub.0.12F.sub.6:0.03 Mn.sup.4+ Embodiment K.sub.1.9Ge.sub.0.905F.sub.6:0.12 Mn.sup.4+@ 4 20 104 3 94 7 K.sub.2.2Si.sub.0.68Ge.sub.0.25F.sub.6:0.02 Mn.sup.4+ Embodiment K.sub.2Ge.sub.0.8F.sub.6:0.2 Mn.sup.4+@ 3 10 101 0.5 94 8 K.sub.2SiF.sub.6 Embodiment K.sub.2Ge.sub.0.82F.sub.6:0.18 Mn.sup.4+@ 3.5 16 109 1.1 95 9 K.sub.2Si.sub.0.95F.sub.6:0.05 Mn.sup.4+ Embodiment K.sub.2Ge.sub.0.82F.sub.6:0.18 Mn.sup.4+@ 1.5 13 105 1.6 93 10 K.sub.2Si.sub.0.98F.sub.6:0.02 Mn.sup.4+ Embodiment K.sub.2.2Ge.sub.0.85F.sub.6:0.1 Mn.sup.4+@ 0.5 12 101 4.3 94 11 K.sub.2Si.sub.0.6Ge.sub.0.25F.sub.6:0.1 Mn.sup.4+ Embodiment K.sub.2.1Ge.sub.0.895F.sub.6:0.08 Mn.sup.4+@ 4.5 40 103 1.2 92 12 K.sub.2Si.sub.0.45Ge.sub.0.45F.sub.6:0.1 Mn.sup.4+ Embodiment K.sub.2.1Ge.sub.0.895F.sub.6:0.08 Mn.sup.4+@ 6 34 108 1.3 93 13 K.sub.2Si.sub.0.47Ge.sub.0.45F.sub.6:0.08 Mn.sup.4+ Embodiment K.sub.2.1Ge.sub.0.895F.sub.6:0.08 Mn.sup.4+@ 4 25 102 2.6 92 14 K.sub.2Si.sub.0.5Ge.sub.0.45F.sub.6:0.05 Mn.sup.4+ Embodiment K.sub.2Ge.sub.0.85F.sub.6:0.15 Mn.sup.4+@ 1 5 107 4.1 92 15 K.sub.2Si.sub.0.6Ge.sub.0.15F.sub.6:0.15 Mn.sup.4+ Embodiment K.sub.2Ge.sub.0.94F.sub.6:0.06 Mn.sup.4+@ 11 33 109 0.5 94 16 K.sub.1.6Si.sub.0.9Ge.sub.0.1F.sub.6:0.1 Mn.sup.4+ Embodiment K.sub.2Ge.sub.0.8F.sub.6:0.2 Mn.sup.4+@ 9 36 105 1.8 95 17 K.sub.1.996Si.sub.0.7Ge.sub.0.241F.sub.6:0.06 Mn.sup.4+ Embodiment K.sub.2Ge.sub.0.8F.sub.6:0.2 Mn.sup.4+@ 15 26 104 0.8 93 18 K.sub.1.996Si.sub.0.7Ge.sub.0.3F.sub.6:0.001 Mn.sup.4+ Embodiment K.sub.2Ge.sub.0.8F.sub.6:0.2 Mn.sup.4+@ 12 45 103 0.6 93 19 K.sub.2Si.sub.0.6Ge.sub.0.4F.sub.6 Embodiment K.sub.2Ge.sub.0.8F.sub.6:0.2 Mn.sup.4+@ 10 24 103 2.5 92 20 K.sub.2Si.sub.0.7Ge.sub.0.3F.sub.6 Embodiment K.sub.2Ge.sub.0.8F.sub.6:0.2 Mn.sup.4+@ 6 21 101 3.1 91 21 K.sub.2Si.sub.0.5Ge.sub.0.5F.sub.6 Note: Taking the luminous flux in the Comparative Example as the reference value 100, the luminous flux in the Embodiments is obtained by dividing their actual luminous flux by the actual luminous flux in the Comparative Example, and then multiplying by 100.

(11) It is apparent that the above-described embodiments are merely illustrative of the examples, and are not intended to limit the implementation modes. Other variations or modifications in different forms may be made by those of ordinary in the art based on the above description. There is no need and no way to exhaust all of the implementation modes. Obvious changes or variations resulting therefrom are still within the scope of protection of the present invention.

(12) The foregoing description of the exemplary embodiments of the present invention has been presented only for the purposes of illustration and description and is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many modifications and variations are possible in light of the above teaching.

(13) The embodiments were chosen and described in order to explain the principles of the invention and their practical application so as to activate others skilled in the art to utilize the invention and various embodiments and with various modifications as are suited to the particular use contemplated. Alternative embodiments will become apparent to those skilled in the art to which the present invention pertains without departing from its spirit and scope. Accordingly, the scope of the present invention is defined by the appended claims rather than the foregoing description and the exemplary embodiments described therein.