Red phosphor, method for producing the same, and use

Abstract

This application discloses a red phosphor, a method for manufacturing the same, and its use, and relates to the technical field of luminescent materials. The chemical composition of the red phosphor is A2M (1-x) F6:xMn 4+ (where A is at least one selected from alkali metal elements, M is at least one selected from Group 4 elements or Ti element, and the value range of x satisfies 0 < x ≦ 0.05). The red phosphor is in a particulate form, and the concentration of tetravalent manganese ions gradually decreases in the radial direction from the center of the red phosphor particles to its surface. In this application, due to the concentration of the activator Mn 4+ distributing in a descending gradient in the radial direction from the center of the red phosphor particles to its surface, the erosion of the phosphor powder by water vapor is buffered, its anti-aging property is improved, and the service life is further extended.

Description

[Technical Field]

[0001] This application relates to the technical field of luminescent materials, and more particularly to red phosphors, methods for producing the same, and uses thereof. [Background technology]

[0002] Paulusz of the German company Osram first produced K2SiF6:Mn in 1973. 4+ While fluoride fluorescent materials were reported, and research into fluoride fluorescent materials has gradually become a focus for industrialization since 2006, K2SiF6:Mn activated with tetravalent manganese has been reported. 4+ The phosphor has low water resistance, that is, the Mn present on the surface of the phosphor particles. 4+ When exposed to moisture in the air, it oxidizes to dark-colored manganese oxide, resulting in a decrease in the brightness of the phosphor during use and a shortened service life.

[0003] Related technologies include synthesized K2SiF6:Mn 4+ It has been disclosed that fluoride phosphors undergo surface reduction, i.e., a shell structure of non-tetravalent Mn is constructed, which undoubtedly disrupts the crystal structure of the particle surface, resulting in the destruction of a crystal field structure with a small manganese layer on the surface, a decrease in luminescence efficiency, and the destruction of the surface lattice of the phosphor particles, creating a potential pathway for degradation by water vapor erosion. In harsh aging environments, Mn 4+ When water molecules penetrate the shell surface that has not been doped with an activator, creating water molecule channels, K2SiF6:Mn 4+ The phosphor's resistance to degradation decreases rapidly. Mn 4+ If the shell thickness of the shell that has not been doped with an activator increases further, K2SiF6:Mn 4+ This affects the absorption of blue light by the phosphor, reducing quantum efficiency. [Overview of the project] [Problems that the invention aims to solve]

[0004] The present application provides a red phosphor, a method for manufacturing the same, and uses thereof. The concentration of the activator Mn in the radial direction from the center to the surface of the red phosphor particles decreases in a descending gradient, thereby buffering the erosion of the phosphor powder by water vapor. Further, in the present application, the concentration of tetravalent manganese ions on the surface of the red phosphor particles gradually decreases to zero in order to synthesize a manganese-free shell layer in situ. The manganese-free shell layer avoids the destruction of the crystal surface lattice caused by post-treatment with a reducing agent, protects the structure of the crystal itself, and can further improve the anti-aging ability (or anti-deterioration ability) of the phosphor powder. 4+ The erosion of the phosphor powder by water vapor is buffered by the concentration of 4+ decreasing in a descending gradient from the center to the surface of the red phosphor particles. Further, in the present application, the concentration of tetravalent manganese ions on the surface of the red phosphor particles gradually decreases to zero for synthesizing a manganese-free shell layer in situ. The manganese-free shell layer avoids the destruction of the crystal surface lattice caused by post-treatment with a reducing agent, protects the structure of the crystal itself, and can further improve the anti-aging ability (or anti-deterioration ability) of the phosphor powder.

Means for Solving the Problems

[0005] In a first aspect, the present application provides a red phosphor, which is any one selected from the substances represented by Formula I. A2M (1-x) F6:xMn 4+ Formula I In Formula I, A is at least one selected from alkali metal elements, M is at least one selected from Group 1 4 elements or Ti element, the range of the value of x is 0 < x ≦ 0.05, the red phosphor is in particle form, and the concentration of tetravalent manganese ions gradually decreases in the radial direction from the center to the surface of the red phosphor particles. In some embodiments, in Formula I, A is at least one selected from Na element and K element, and M is at least one selected from Si element, Ge element, and Ti element. In some embodiments, in Formula I, A is at least one selected from Na element and K element, or M is at least one selected from Si element, Ge element, and Ti element. Preferably, in some embodiments, A is K element, or M is Si element. More preferably, in some embodiments, A is K element and M is Si element. In the present application, the activator Mn in the radial direction from the center to the surface of the red phosphor particles 4+The distribution of the concentration in a descending gradient buffers the erosion of the phosphor powder by water vapor and further extends the service life of the phosphor.

[0006] In some embodiments, the concentration of tetravalent manganese ions decreases linearly and uniformly in the radial direction from the center of the red phosphor particles toward their surface. In this way, the phosphor powder has better anti-aging properties and further contributes to extending the service life.

[0007] In some embodiments, the concentration of tetravalent manganese ions on the surface of the red phosphor particles is zero. At this time, a manganese-free shell layer is formed in situ on the surface of the red phosphor particles, and the manganese-free shell layer can further improve the anti-aging property of the phosphor powder.

[0008] As shown in FIG. 1, the shape of the red phosphor particles is substantially spherical. The center of the red phosphor particles with a substantially spherical structure can be determined using a high-energy ion beam. Specifically, the high-energy ion beam cuts the red phosphor particles along the center of the height, and the newly cut surface is shown in FIG. 2. Take two line segments LL′ and L1L1′ (the two longest line segments available on the new surface) connecting the particle surface, and let the intersection of LL′ and L1L1′ be O. The region surrounded by O as the center and r as the radius can be regarded as the center A of the red phosphor particles described in the present application. Here, 0 ≦ r ≦ 0.1R, where R is the radius of the red phosphor particles. The median diameter of the red phosphor particles is 20 μm to 40 μm. Preferably, the median diameter of the red phosphor particles is 28 to 32 μm. More preferably, the median diameter of the red phosphor particles is 30 μm. A determined by the above method is the center (or body center) of the red phosphor particles, and B is an arbitrarily selected point on the outer edge of the new surface of the red phosphor particles. However, in the present application, the specific position is not limited as long as it is on the outer surface of the red phosphor particles. The direction extending from point A toward point B is the radial direction from the center of the red phosphor particles toward their surface, that is, Mn 4+The concentration of gradually decreases in the direction extending from point A to point B, preferably Mn 4+ The concentration of decreases linearly and uniformly in the direction extending from point A to point B, and more preferably, the concentration of Mn at point B. 4+ The concentration is zero.

[0009] In some embodiments, if the percentage content of manganese atoms at the center of the red phosphor particle is x1% and the percentage content of manganese atoms at the surface of the red phosphor particle is x2%, then 0 ≤ x2 / x1 < 1 is satisfied. By controlling the ratio of the manganese atom content at the surface of the red phosphor particle to the manganese atom content at the center within an appropriate range, erosion of the phosphor powder by water vapor can be buffered, and the anti-aging ability of the phosphor powder can be sustained. Exemplarily, the ratio x2 / x1 of the percentage content of manganese atoms at the surface of the red phosphor particle to the percentage content of manganese atoms at the center of the red phosphor particle is in the range of 0, 0.05, 0.1, 0.15, 0.18, 0.19, 0.2, 0.25, 0.3, 0.33, 0.35, 0.5, 0.6, 0.7, 0.8, 0.9, or any two of the above values. Preferably, in some embodiments, 0 ≤ x2 / x1 ≤ 0.33 is satisfied. More preferably, in some embodiments, 0 ≤ x² / x¹ < 0.2 is satisfied.

[0010] In some embodiments, if the percentage content of manganese atoms at the center of the red phosphor particle is x1%, then 0.1 ≤ x1 ≤ 5. The percentage content of manganese atoms at the center A of the red phosphor particle is at most 5%, and if the percentage content of manganese atoms at the center of the red phosphor particle is too high (e.g., more than 5%), it does not help to improve the luminescence intensity and the luminescence performance decreases. The percentage content of manganese atoms at the center of the phosphor particle is at least 0.1%, and if the percentage content of manganese atoms at the center of the phosphor particle is too low (e.g., less than 0.1%), the activator Mn doped into the powder 4+The content is too low to improve luminescence performance. For example, the percentage manganese content x1% at the center of the red phosphor particles is in the range of 0.1%, 0.3%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.5%, 2%, 3%, 4%, 5%, or any two of the above values. Preferably, in some embodiments, 0.5 ≤ x1 ≤ 1 is satisfied.

[0011] In some embodiments, when the percentage content of manganese atoms on the surface of the red phosphor particles is x2%, the condition 0 ≤ x2 < 0.1 is satisfied. In this case, the anti-aging properties are superior. For example, the atomic percentage of manganese x2% on the surface of the red phosphor particles is in the range of 0%, 0.01%, 0.03%, 0.05%, 0.06%, 0.08%, 0.09%, or any two of the above values.

[0012] In a second aspect, the present application provides a method for producing the red phosphor described above, comprising the following steps (1), (2), and (3). (1) Obtain a mixed solution of source A and hydrofluoric acid aqueous solution, and call this solution A. Here, the A source includes at least one of A fluoride, A hydrogen fluoride, A sulfate, A nitrate, A bisulfate, A carbonate, or A bicarbonate. The hydrofluoric acid content in the aforementioned hydrofluoric acid aqueous solution is 40% by mass. (2) Obtain a mixed solution of the Mn source and the M source (H2MF6 hydrofluoric acid solution) and use it as the BX solution. Here, the H2MF6 content in the H2MF6 hydrofluoric acid solution is 20% to 40% by mass, and the BX solution is BX1 solution, BX2 solution, ..., BX n The solution contains n≧5 and the content of the Mn source is from the BX1 solution to the BX n The solution gradually decreases, and optionally, the BX n The Mn source content in the solution is 0. That is, the BX n The amount of Mn source in the solution may be 0 or not, and the BX nWhen the Mn source content in the solution is 0, a manganese-free shell layer is synthesized in situ on the surface of the red phosphor particles, and this manganese-free shell layer is composed of Mn present on the surface of the phosphor particles. 4+ This effectively prevents exposure to moisture in the air, further improving the anti-aging ability of the phosphor powder. (3) BX1 solution n The BX solution from step (2) is injected into the A solution from step (1) in the order of the solutions, and the reaction is allowed to occur to obtain the red phosphor.

[0013] Furthermore, the order of steps (1) and (2) is not limited; solution A may be prepared first and then solution BX, or solution BX may be prepared first and then solution A, or the order may be selected according to the actual situation, and this application does not limit the order.

[0014] In some embodiments, in step (2), the content of the Mn source is reduced from the BX1 solution to the BX n The amount of Mn source decreases linearly and uniformly down to the solution, and optionally, the amount of Mn source decreases from the BX1 solution to the BX n The solution decreases uniformly, like an arithmetic progression.

[0015] In some embodiments, in step (3), the injection rate of the BX solution is 10-50 mL / s, the injection interval is 5-15 min, and the reaction conditions are a reaction temperature of 40-50°C and a reaction time of 2-4 h.

[0016] In some embodiments, in step (1), the mass ratio of the A source to the hydrofluoric acid is 20-25:95-105, and in step (2), the molar percentage of the Mn source to the M source in the BX1 solution is M1, and the BX n In the solution, the molar percentage of the Mn source to the M source is M2, and the condition 0 ≤ M2 / M1 < 1 is satisfied.

[0017] In a third aspect, the present application discloses the use of the above-mentioned red phosphor, or a red phosphor manufactured by the above-mentioned manufacturing method, in the field of liquid crystal backlights or LED lighting.

[0018] In a fourth aspect, the present application discloses a liquid crystal backlight comprising an excitation chip and a phosphor coated on the excitation chip, wherein the phosphor is the red phosphor described above or a red phosphor manufactured by the manufacturing method described above.

[0019] In a fifth aspect, the present application discloses an illumination device comprising a light-emitting device, the light-emitting device comprising an excitation chip and a phosphor coated on the excitation chip, wherein the phosphor is the red phosphor described above or a red phosphor manufactured by the manufacturing method described above. [Effects of the Invention]

[0020] The beneficial effects brought about by the technical solutions provided by some embodiments of the present application include at least the following: In the present application, the radial activator Mn from the center of the red phosphor particle toward its surface 4+ The downward gradient distribution of the concentration of the activator Mn buffers the erosion of the phosphor powder by water vapor, 4+ Compared to conventional phosphor powders where the concentration is set without a gradient, the anti-aging properties are superior. In particular, the activator Mn 4+ The linear and uniform downward distribution of the concentration of manganese is more beneficial in improving anti-aging properties and extending the service life of the manufactured phosphor than when it is distributed with a non-linear and non-uniform downward slope. Furthermore, this invention allows for the gradual reduction of the concentration of tetravalent manganese ions on the surface of the red phosphor particles to zero, thereby synthesizing a manganese-free shell layer in situ on the surface of the phosphor powder. This is advantageous in protecting the crystal lattice of the crystal structure itself and further improving the anti-aging properties of the phosphor powder. [Brief explanation of the drawing]

[0021] To more clearly explain the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings necessary for describing the embodiments or the prior art. However, the drawings in the following description are only a few embodiments of the present application, and it is clear to those skilled in the art that other drawings can be obtained based on these drawings without any creative effort. [Figure 1] This is a scanning electron microscope image of the K2SiF6:Mn4+ phosphor manufactured in Example 1 of the present application. [Figure 2] This figure shows a new surface obtained by cutting the K2SiF6:Mn4+ phosphor produced in Example 1 with two beam ions. [Figure 3] This figure shows the line scanning path of the EDX line scanning from the center A to the surface B of the K2SiF6:Mn4+ phosphor manufactured in Example 1. [Figure 4] Figure 3 shows the elemental content obtained by scanning the EDX line. [Figure 5] This is a schematic diagram of point sampling when the K2SiF6:Mn4+ phosphor produced in Example 1 of this application is subjected to energy spectral analysis. [Figure 6] Figure 5 is a schematic diagram showing the distribution curve of the relative Mn4+ content at the sampling locations of Examples 1 to 5, which were tested by point sampling. [Modes for carrying out the invention]

[0022] To further clarify the purpose, technical solutions, and advantages of this application, the application will be described in more detail below with reference to the drawings and examples. It should be understood that the specific examples described herein are used solely for illustrative purposes and are not intended to limit the application.

[0023] The present invention will be further described below with reference to examples, but all other fluorescent materials used in the examples of the present invention can be purchased commercially.

[0024] KSF Phosphor Manufacturing (K2SiF6:Mn 4+ (Manufacturing)

[0025] Example 1 (1) Preparation of BX solution: Weigh out 2.7g, 2.52g, 2.34g, 2.16g, 1.98g, 1.80g, 1.62g, 1.44g, 1.26g, 1.08g, 0.9g, 0.72g, 0.54g, 0.36g, 0.18g, and 0g of K2MnF, and dissolve each in 50g of commercially available 30%~32% HSF (i.e., 30%~32% aqueous fluorosilicic acid solution) to create BX1 solution (containing 2.7g of K2MnF), BX2 solution, ..., BX 16 Sixteen sets of BX solutions were obtained, sequentially corresponding to the solutions (without K2MnF6). (2) Preparation of Solution A: 21 g of potassium hydrogen fluoride was weighed and dissolved in 250 ml of 40% HF aqueous solution (i.e., 40% hydrofluoric acid aqueous solution) to obtain Solution A. (3) BX1 solution 16 The prepared BX solution was injected into solution A at an injection rate of 10 mL / s at 6 min intervals, in the order of the solutions. The mixture was stirred for 2 hours at a temperature of 40°C, then allowed to stand and separated. (4) Post-treatment: Discard the supernatant, add a 5% HF aqueous solution (5% hydrofluoric acid aqueous solution), wash twice by stirring, wash twice with anhydrous ethanol, and bake under conditions of drying with air blowing at 60°C. The median diameter of the KSF phosphor produced in Example 1 was 30 μm. Figure 1 shows K2SiF6:Mn produced in Example 1 of this application. 4+ This is a scanning electron microscope image of the phosphor, and as can be seen from Figure 1, it shows the K2SiF6:Mn produced in Example 1. 4+ The phosphor has a roughly spherical shape, and Figure 2 shows the K2SiF6:Mn produced in Example 1. 4+ This figure shows a new surface obtained by cutting the phosphor with two beam ions, and Figure 3 shows the K2SiF6:Mn produced in Example 1. 4+Figure 4 shows the line scanning path obtained by EDX line scanning from the center A of the phosphor to the surface B. Figure 4 is a schematic diagram showing the elemental content obtained by EDX line scanning in Figure 3. The vertical coordinate CPS in Figure 4 indicates that the count has no special physical meaning and shows the intensity of the detected elemental signal. Figure 5 shows the K2SiF6:Mn produced in Example 1. 4+ Figure 6 is a schematic diagram of point sampling when a phosphor is subjected to energy spectral analysis. Figure 6 shows the Mn at the point sampling locations in Example 1, which was tested by point sampling as shown in Figure 5. 4+ This is a schematic diagram showing the distribution curve of the relative content of K2SiF6:Mn produced in Example 1. 4+ The concentration of tetravalent manganese ions in the radial direction from the center of the red phosphor particles toward their surface decreased linearly and uniformly to zero.

[0026] Example 2 (1) Preparation of BX solution: Weigh out 62.7g, 2.23g, 1.87g, 1.57g, 1.34g, 1.14g, 0.95g, 0.74g, 0.59g, 0.46g, 0.34g, 0.22g, 0.15g, 0.07g, 0.03g, and 0g of K2MnF, and dissolve each in 50g of commercially available 30%~32% HSF to make BX1 solution (containing 62.7g of K2MnF), BX2 solution, ..., BX 16 Sixteen sets of BX solutions were obtained, sequentially corresponding to the solutions (without K2MnF6). (2) Preparation of Solution A: 21 g of potassium hydrogen fluoride was weighed and dissolved in 250 ml of 40% HF aqueous solution to obtain Solution A. (3) BX1 solution 16 The prepared BX solution was injected into solution A at an injection rate of 15 mL / s at 10 min intervals, in the order of solution to solution. The mixture was stirred for 4 hours at a temperature of 50°C, then allowed to stand and separated. (4) Post-treatment: Discard the supernatant, add a 5% HF aqueous solution, wash twice with stirring, wash twice with anhydrous ethanol, and bake under conditions of drying with air blowing at 60°C. The median diameter of the KSF phosphor produced in Example 2 was 30 μm. As can be seen from Figure 6, the concentration of tetravalent manganese ions in the radial direction from the center to the surface of the red phosphor particles produced in Example 2 decreased non-linearly to zero.

[0027] Example 3 (1) Preparation of BX solution: Weigh out 62.7g, 1.77g, 1.27g, 1.00g, 0.79g, 0.61g, 0.48g, 0.39g, 0.30g, 0.23g, 0.17g, 0.12g, 0.08g, 0.04g, 0.02g, and 0g of K2MnF, and dissolve each in 50g of commercially available 30%~32% HSF to make BX1 solution (containing 62.7g of K2MnF), BX2 solution, ..., BX 16 Sixteen sets of BX solutions were obtained, sequentially corresponding to the solutions (without K2MnF6). (2) Preparation of Solution A: 21 g of potassium hydrogen fluoride was weighed and dissolved in 250 ml of 40% HF aqueous solution to obtain Solution A. (3) BX1 solution 16 The prepared BX solution was injected into solution A at an injection rate of 35 mL / s at 13 min intervals, in the order of the solutions. The mixture was stirred for 3 hours at a temperature of 45°C, then allowed to stand and separated. (4) Post-treatment: Discard the supernatant, add a 5% HF aqueous solution, wash twice with stirring, wash twice with anhydrous ethanol, and bake under conditions of drying with air blowing at 60°C. The median diameter of the KSF phosphor produced in Example 3 was 30 μm. As can be seen from Figure 6, the concentration of tetravalent manganese ions in the radial direction from the center to the surface of the red phosphor particles produced in Example 3 decreased nonlinearly and non-uniformly to zero.

[0028] Example 4 (1) Preparation of BX solution: Weigh out 62.7g, 2.65g, 2.6g, 2.52g, 2.43g, 2.37g, 2.24g, 2.07g, 1.91g, 1.76g, 1.57g, 1.38g, 1.16g, 0.86g, 0.52g, and 0g of K2MnF, and dissolve each in 50g of commercially available 30%~32% HSF to make BX1 solution (containing 62.7g of K2MnF), BX2 solution, ..., BX 16Sixteen sets of BX solutions were obtained, sequentially corresponding to the solutions (without K2MnF6). (2) Preparation of Solution A: 21 g of potassium hydrogen fluoride was weighed and dissolved in 250 ml of 40% HF aqueous solution to obtain Solution A. (3) BX1 solution 16 The prepared BX solution was injected into solution A at an injection rate of 50 mL / s at 15 min intervals, in the order of the solutions. The mixture was stirred for 4 hours at a temperature of 45°C, then allowed to stand and separated. (4) Post-treatment: Discard the supernatant, add a 5% HF aqueous solution, wash twice with stirring, wash twice with anhydrous ethanol, and bake under conditions of drying with air blowing at 60°C. The median diameter of the KSF phosphor produced in Example 4 was 30 μm. As can be seen from Figure 6, the concentration of tetravalent manganese ions in the radial direction from the center to the surface of the red phosphor particles produced in Example 4 decreased non-linearly to zero.

[0029] Example 5 (1) Preparation of BX solution: Weigh out 62.7g, 2.69g, 2.68g, 2.68g, 2.66g, 2.63g, 2.58g, 2.51g, 2.40g, 2.25g, 2.05g, 1.81g, 1.58g, 1.32g, 0.89g, and 0g of K2MnF, and dissolve each in 50g of commercially available 30%~32% HSF to make BX1 solution (containing 62.7g of K2MnF), BX2 solution, ..., BX 16 Sixteen sets of BX solutions were obtained, sequentially corresponding to the solutions (without K2MnF6). (2) Preparation of Solution A: 21 g of potassium hydrogen fluoride was weighed and dissolved in 250 ml of 40% HF aqueous solution to obtain Solution A. (3) BX1 solution 16 The prepared BX solution was injected into solution A at an injection rate of 10 mL / s at 6 min intervals, in the order of the solutions. The mixture was stirred for 2 hours at a temperature of 45°C, then allowed to stand and separated. (4) Post-treatment: Discard the supernatant, add a 5% HF aqueous solution, wash twice with stirring, wash twice with anhydrous ethanol, and bake under conditions of drying with air blowing at 60°C. The median diameter of the KSF phosphor produced in Example 5 was 30 μm. As can be seen from Figure 6, the concentration of tetravalent manganese ions in the radial direction from the center to the surface of the red phosphor particles produced in Example 5 decreased nonlinearly and non-uniformly to zero.

[0030] [Table 1]

[0031] Manufacturing of other phosphors

[0032] Example 1 (1) In an ice bath, 150 g of germanium oxide GeO2 was added to 850 g of a 50% hydrofluoric acid aqueous solution and mechanically stirred for 1 hour to obtain a 30% by mass solution of fluorogermanic acid H2GeF6. (2) Preparation of BX solution: Weigh out 2.7g, 2.52g, 2.34g, 2.16g, 1.98g, 1.80g, 1.62g, 1.44g, 1.26g, 1.08g, 0.9g, 0.72g, 0.54g, 0.36g, 0.18g, and 0g of K2MnF6, dissolve each in 50g of 30% by mass of homemade fluorogermanic acid, and prepare BX1 solution (containing 2.7g of K2MnF6), BX2 solution, ..., BX 16 Sixteen sets of BX solutions were obtained, sequentially corresponding to the solutions (without K2MnF6). (3) Preparation of Solution A: 21 g of potassium hydrogen fluoride was weighed and dissolved in 250 ml of 40% HF aqueous solution (i.e., 40% hydrofluoric acid aqueous solution) to obtain Solution A. (4) From BX1 solution to BX 16 The prepared BX solution was injected into solution A at an injection rate of 10 mL / s at 6 min intervals, in the order of the solutions. The mixture was stirred for 2 hours at a temperature of 40°C, then allowed to stand and separated. (5) Post-treatment: Discard the supernatant, add a 5% HF aqueous solution (5% hydrofluoric acid aqueous solution), wash twice by stirring, wash twice with anhydrous ethanol, and bake under conditions of drying with air blowing at 60°C. K2Ge manufactured in Example 1 (1-x) F6:xMn 4+ The median diameter of the phosphor was 30 μm.

[0033] Example 2 (1) In an ice bath, 146 g of titanium dioxide (TiO2) was added to 854 g of a 50% hydrofluoric acid aqueous solution and mechanically stirred for 1 hour to obtain a 30% by mass solution of fluorogermanic acid (H2TiF6). (2) Preparation of BX solution: Weigh out 2.7g, 2.52g, 2.34g, 2.16g, 1.98g, 1.80g, 1.62g, 1.44g, 1.26g, 1.08g, 0.9g, 0.72g, 0.54g, 0.36g, 0.18g, and 0g of K2MnF6, dissolve each in 50g of 30% by mass of homemade fluorotitanium acid, and prepare BX1 solution (containing 2.7g of K2MnF6), BX2 solution, ..., BX 16 Sixteen sets of BX solutions were obtained, sequentially corresponding to the solutions (without K2MnF6). (3) Preparation of Solution A: 21 g of potassium hydrogen fluoride was weighed and dissolved in 250 ml of 40% HF aqueous solution (i.e., 40% hydrofluoric acid aqueous solution) to obtain Solution A. (4) From BX1 solution to BX 16 The prepared BX solution was injected into solution A at an injection rate of 10 mL / s at 6 min intervals, in the order of the solutions. The mixture was stirred for 2 hours at a temperature of 40°C, then allowed to stand and separated. (5) Post-treatment: Discard the supernatant, add a 5% HF aqueous solution (5% hydrofluoric acid aqueous solution), wash by stirring twice, wash twice with anhydrous ethanol, and bake under conditions of drying with air blowing at 60°C. K2Ti manufactured in Example 2 (1-x) F6:xMn 4+ The median diameter of the phosphor was 30 μm.

[0034] Example 3 (1) In an ice bath, 344 g of germanium oxide GeO2 was added to 656 g of a 50% hydrofluoric acid aqueous solution and mechanically stirred for 1 hour to obtain a 30% by mass solution of fluorogermanic acid H2GeF6. (2) Preparation of BX solution: Weigh out 2.35g, 2.19g, 2.04g, 1.88g, 1.72g, 1.57g, 1.41g, 1.25g, 1.10g, 0.94g, 0.78g, 0.63g, 0.47g, 0.31g, 0.16g, and 0g of Na2MnF6, dissolve each in 50g of 30% by mass of homemade fluorogermanic acid, and prepare BX1 solution (containing 2.35g of Na2MnF6), BX2 solution, ..., BX 16 Sixteen sets of BX solutions were obtained, sequentially corresponding to the solutions (which did not contain Na2MnF6). (3) Preparation of Solution A: 16.6 g of sodium fluoride was weighed and dissolved in 250 ml of 40% HF aqueous solution (i.e., 40% hydrofluoric acid aqueous solution) to obtain Solution A. (4) From BX1 solution to BX 16 The prepared BX solution was injected into solution A at an injection rate of 10 mL / s at 6 min intervals, in the order of the solutions. The mixture was stirred for 2 hours at a temperature of 40°C, then allowed to stand and separated. (5) Post-treatment: Discard the supernatant, add a 5% HF aqueous solution (5% hydrofluoric acid aqueous solution), wash by stirring twice, wash twice with anhydrous ethanol, and bake under conditions of drying with air blowing at 60°C. Na2Ge produced in Example 3 (1-x) F6:xMn 4+ The median diameter of the phosphor was 30 μm.

[0035] Energy Spectral Analysis Test The KSF phosphors produced in Examples 1-5 were cut using a dual ion beam, and 16 points were taken at equal intervals from the center A to the surface B of the new surface for energy spectral analysis. As shown in Figure 5, Figure 5 is a schematic diagram of the point sampling when the KSF phosphor produced in Example 1 is subjected to energy spectral analysis. The percentage of Mn atoms at the point sampling locations is shown in Table 2 and Figure 6. The point sampling method for the KSF phosphors produced in Examples 2-5 can be described by referring to the point sampling method of Example 1 in Figure 5, and the percentage of Mn atoms at the point sampling locations is shown in Table 2 and Figure 6, which will not be explained again here.

[0036] [Table 2]

[0037] As can be seen from Table 2 and Figure 6, the red phosphor particles produced in Examples 1-5 show a gradual decrease in the concentration of tetravalent manganese ions in the radial direction from the center toward the surface, as shown in Figure 6. 4+ From the decreasing trend in concentration, the Mn of Example 1 4+ The concentration of Mn decreases linearly and uniformly in the radial direction from the center of the particle toward its surface, particularly in an arithmetic progression, and the decreasing trend shows a straight line, with the distance between two adjacent points on the line being equal. 4+ The concentration of Mn decreases non-uniformly in the radial direction from the center toward its surface, and the decreasing trend is curvilinear, and the Mn on the particle surface of Examples 1-5 4+ It was found that the concentrations of all substances were 0.

[0038] Example 6 When preparing BX solution, BX1 solution is used to produce BX 10 Only the solution was produced, and that is, in the KSF phosphor produced in Example 6, the ratio of the atomic percentage content of manganese at the surface x2 to the atomic percentage content of manganese at the center x1 x2 / x1 was 0.395, except that it was the same as in Example 1.

[0039] Example 7 When preparing BX solution, BX1 solution is used to produce BX 12 Only the solution was produced; that is, the KSF phosphor produced in Example 7 did not contain a manganese-free shell layer, and the ratio of the atomic percentage content of manganese at its surface x2 to the atomic percentage content of manganese at its center x1 (x2 / x1) was 0.26, except that it was the same as in Example 1.

[0040] Example 8 When preparing BX solution, BX1 solution is used to produce BX 14Only the solution was produced; that is, the KSF phosphor produced in Example 8 did not contain a manganese-free shell layer, and the ratio of the atomic percentage content of manganese at its surface x2 to the atomic percentage content of manganese at its center x1 (x2 / x1) was 0.14, except that it was the same as in Example 1.

[0041] Comparative Example 1 The process for preparing the BX solution was the same as in Example 1, except that all of the K2MnF6 was added directly to 10%-15% HSF, i.e., not added with a downward gradient. Specifically, 21.6g of K2MnF6 was weighed, dissolved in 800g of commercially available 10%-15% HSF, divided into 16 equal parts, and 16 sets of BX1-BX with the same K2MnF6 content were prepared. 16 A solution is obtained, and then the BX1 to BX 16 The solution was sequentially injected into solution A at an injection rate of 10 mL / s at intervals of 6 minutes, and the rest was the same as in Example 1. Table 3 shows the test method and apparatus for the 1000-hour aging test in this application, and Table 4 shows Examples 1 to 8, Example 1 to 3 The aging test data for the phosphors produced in Comparative Example 1 are shown (Explanation: KSF-0 is the sample from Comparative Example 1, KSF-1 is the sample from Example 1, KSF-2 is the sample from Example 2, KSF-3 is the sample from Example 3, KSF-4 is the sample from Example 4, KSF-5 is the sample from Example 5, KSF-6 is the sample from Example 6, KSF-7 is the sample from Example 7, KSF-8 is the sample from Example 8, KSF-9 is the sample from Example 1, KSF-10 is the sample from Example 2, and KSF-11 is the sample from Example 3).

[0042] [Table 3]

[0043] [Table 4]

[0044] Combining the data in Table 4, it was found that a gradual decrease in the concentration of tetravalent manganese ions in the phosphor particles along the radial direction is advantageous for improving anti-aging properties. In Comparative Example 1, where no gradient setting for the concentration of tetravalent manganese ions was performed, the luminous flux value at 0h was 128.30lm, and the luminous flux value after 1000h of use was only 123.56lm, a decrease of 4.74lm. Furthermore, the phosphor produced in Comparative Example 1 showed a significant decrease in brightness from 100% initially to 96.2% after 1000h of use. However, in Example 1, where the concentration of tetravalent manganese ions was set with a downward gradient in the radial direction as described in this application, the luminous flux after 1000h of use decreased by only 1.16lm compared to the luminous flux at 0h, and the brightness ratio of the phosphor produced in Example 1 was able to reach 99.1% even after 1000h of use. From this, it was found that phosphors with a downward gradient setting for the concentration of tetravalent manganese ions have a longer service life. Comparing KSF-2 to KSF-5 with KSF-1, the linear and uniform decrease in the concentration of tetravalent manganese ions in the radial direction from the center to the surface of the phosphor particles is advantageous for improving the phosphor's anti-aging properties and also enhances its ability to delay erosion by water vapor.

[0045] Comparing KSF-9 to KSF-11 with KSF-1, the phosphor performance is best when A is the K element and M is the Si element, and it can be seen that potassium hydrogen fluoride and fluorosilicic acid are preferable as the A and M sources.

[0046] As should be understood, the embodiments described above are merely examples of embodiments used to illustrate the principles of the present invention, but the present invention is not limited thereto. Those skilled in the art will be able to make various modifications and improvements without departing from the spirit and essence of the present invention, and such modifications and improvements will be considered within the scope of the protection of the present invention.

Claims

1. A red phosphor activated with a tetravalent manganese ion, wherein the red phosphor is selected from the substances represented by formula I. A ２ M （１－ｘ） F ６ : xMn ４＋ Formula I In formula I, A is at least one element selected from alkali metal elements. M is at least one element selected from Group 14 elements or the Ti element. The range of x is 0 < x ≤ 0.

05. The aforementioned red phosphor is in particulate form, The concentration of tetravalent manganese ions gradually decreases radially from the center of the red phosphor particle toward its surface. A red phosphor activated with tetravalent manganese ions, characterized in that the concentration of tetravalent manganese ions on the surface of the red phosphor particles is zero.

2. In formula I, A is at least one element selected from Na and K, and / or The red phosphor activated with a tetravalent manganese ion according to claim 1, characterized in that M is at least one selected from Si, Ge, or Ti.

3. The percentage content of manganese atoms at the center of the aforementioned red phosphor particle is x １ %, the percentage content of manganese atoms on the surface of the red phosphor particles is x ２ If we use %, then 0 ≤ x ２ / x １ A red phosphor activated with a tetravalent manganese ion as described in claim 1, satisfying the condition <1.

4. 0 ≤ x ２ / x １ ≤ 0.33, characterized in that it is a red phosphor activated by tetravalent manganese ions according to claim 3.

5. The percentage content of manganese atoms at the center of the aforementioned red phosphor particle is x １ If we express this as a percentage, then 0.1 ≤ x １ A red phosphor activated with a tetravalent manganese ion according to claim 3, characterized in that it satisfies ≤ 5.

6. The percentage content of manganese atoms at the center of the aforementioned red phosphor particle is x １ If we express it as a percentage, then 0.5 ≤ x １ A red phosphor activated with a tetravalent manganese ion according to claim 5, characterized in that it satisfies ≤ 1.

7. The percentage content of manganese atoms on the surface of the red phosphor particles is x ２ If we use %, then 0 ≤ x ２ A red phosphor activated with a tetravalent manganese ion according to claim 3, characterized in that it satisfies ≤ 0.

1.

8. Step (1) involves obtaining a mixed solution of source A and hydrofluoric acid aqueous solution, and using this as solution A. Step (2) involves obtaining a mixed solution of the Mn source and the M source, and converting it into a BX solution, The BX solution is BX １ solution, BX ２ Solution, ..., BX ｎ The solution contains n≧5 and the content of the Mn source is the same as described above. １ From the solution, the BX ｎ Step (2) of gradually reducing to a solution, BX １ BX from solution ｎ The process includes step (3), in which the BX solution from step (2) is sequentially injected into the A solution from step (1) in the order of the solutions, and the reaction is carried out to obtain the red phosphor. A method for producing a red phosphor activated with tetravalent manganese ions according to any one of claims 1 to 7, characterized in that the content of the Mn source in the BXn solution is 0.

9. In step (3), the injection rate of the BX solution is 10 to 50 mL / s, and the injection interval is 5 to 15 min. The manufacturing method according to claim 8, characterized in that the reaction conditions are a reaction temperature of 40 to 50°C and a reaction time of 2 to 4 hours.

10. In step (1), the mass ratio of source A to hydrofluoric acid in the hydrofluoric acid aqueous solution is 20-25:95-105. In step (2), the BX １ In the solution, the molar percentage of the Mn source and the M source is M １ The BX ｎ In the solution, the molar percentage of the Mn source and the M source is M ２ Let 0 ≤ M ２ / M １ The manufacturing method according to claim 8, wherein the condition <1> is met.

11. Use of the red phosphor according to any one of claims 1 to 7 in the field of liquid crystal backlights or LED lighting.

12. The device comprises an excitation chip and a phosphor coated on the excitation chip, The liquid crystal backlight is characterized in that the phosphor is a red phosphor according to any one of claims 1 to 7.

13. Including a light-emitting device, The light-emitting device includes an excitation chip and a phosphor coated on the excitation chip. The lighting device is characterized in that the phosphor is a red phosphor according to any one of claims 1 to 7.

Images