Red phosphor, its manufacturing method 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 in particular to red phosphors, their manufacturing methods and uses. [Background technology]

[0002] Paulusz of Osram in Germany was the first to develop K2SiF6:Mn 4+ Fluoride fluorescent materials have been reported. Since 2006, research on fluoride fluorescent materials has gradually become the focus of industrialization. 4+ The phosphor has low water resistance, i.e., Mn present on the surface of the phosphor particles 4+ When exposed to moisture in the air, it oxidizes to dark manganese oxide, which reduces the brightness and lifespan of the phosphor during use.

[0003] In the related art, the 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 will undoubtedly destroy the crystal structure of the particle surface, resulting in the destruction of the crystal field structure with a low manganese layer on the surface, and also reducing the luminous efficiency. The destruction of the surface lattice of the phosphor particles creates a potential pathway for degradation due to the erosion of water vapor. In harsh aging environments, Mn 4+ When water molecules penetrate the shell surface without activator doping and create water molecule channels, K2SiF6:Mn 4+ The anti-degradation ability of the phosphor drops sharply. 4+ Further increase in shell thickness of the undoped shell leads to the formation of K2SiF6:Mn 4+ This affects the absorption of blue light by the phosphor, reducing quantum efficiency. Summary of the Invention [Problem to be solved by the invention]

[0004] The present application provides a red phosphor, a method for producing the same, and uses thereof, wherein the concentration of the activator Mn in the radial direction from the center to the surface of the red phosphor particles is distributed in a decreasing 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+ By virtue of the fact that the concentration of the activator Mn in the radial direction from the center to the surface of the red phosphor particles is distributed in a decreasing gradient, the erosion of the phosphor powder by water vapor is buffered. 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.

Means for Solving the Problems

[0005] In a first aspect, the present application provides a red phosphor which is any one selected from 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 4 elements or Ti element, the range of the value of x is 0 < x ≦ 0.05, the red phosphor is in particulate 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 concentration of the activator Mn in the radial direction from the center to the surface of the red phosphor particles is distributed in a decreasing gradient, thereby buffering the erosion of the phosphor powder by water vapor and further extending the service life of the phosphor. 4+ By virtue of the fact that the concentration of the activator Mn in the radial direction from the center to the surface of the red phosphor particles is distributed in a decreasing gradient, the erosion of the phosphor powder by water vapor is buffered, and the service life of the phosphor is further extended.

[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 particle to its surface, thus providing the phosphor powder with better anti-aging properties, further contributing to extending its service life.

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

[0008] As shown in FIG. 1, the red phosphor particles have an approximately spherical shape. The center of the approximately spherical red phosphor particle can be determined using a high-energy ion beam. Specifically, the high-energy ion beam cuts the red phosphor particle along the center of its height. The new cut surface is shown in FIG. 2. Two line segments L-L′ and L1L1′ (the two longest line segments available on the new surface) connecting the particle surfaces are taken, and the intersection of L-L′ and L1L1′ is designated as O. The area surrounded by the center O and the radius r can be regarded as the center A of the red phosphor particle described in the present application, where 0≦r≦0.1R, where R is the radius of the red phosphor particle. The median diameter of the red phosphor particle is 20 μm to 40 μm, preferably 28 to 32 μm, and more preferably 30 μm. The point A determined by the above method is the center (or body center) of the red phosphor particle, and the point B is an arbitrarily selected point on the outer edge of the new surface of the red phosphor particle. However, in the present application, the specific position is not limited, and there is no particular limitation as long as it is on the outer surface of the red phosphor particle. The direction extending from the point A to the point B is the radial direction from the center of the red phosphor particle to its surface, that is, Mn 4+ The concentration of gradually decreases in the direction extending from point A to point B, and preferably, Mn 4+The concentration of Mn 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 of is zero.

[0009] In some embodiments, the ratio of the manganese atom content at the center of the red phosphor particle to the manganese atom content at the center of the red phosphor particle, x1%, satisfies 0≦x2 / x1<1. 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 of the red phosphor particle within an appropriate range, the phosphor powder can be protected from erosion by water vapor and the phosphor powder's anti-aging ability can be maintained. For example, the ratio x2 / x1 of the manganese atom content at the surface of the red phosphor particle to the manganese atom content at the center of the red phosphor particle is 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 a range consisting of any two of the above values. Preferably, in some embodiments, the ratio 0≦x2 / x1≦0.33 satisfies 0≦x2 / x1<0.33. More preferably, in some embodiments, 0≦x2 / x1<0.2 is satisfied.

[0010] In some embodiments, when the percentage content of manganese atoms at the center of the red phosphor particle is x1%, the following relationship is satisfied: 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 will not contribute to improving the luminous intensity and will result in a decrease in luminous performance. 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 in the powder will be depleted. 4+The content of manganese atoms at the center of the red phosphor particle, x1%, is too low and therefore does not contribute to improving luminous performance. Illustratively, the percentage content of manganese atoms at the center of the red phosphor particle, x1%, is 0.1%, 0.3%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.5%, 2%, 3%, 4%, 5%, or a range consisting of any two of the above values. Preferably, in some embodiments, 0.5≦x1≦1 is satisfied.

[0011] In some embodiments, the atomic percentage of manganese on the surface of the red phosphor particles x2% satisfies 0≦x2<0.1, thereby providing better anti-aging properties. Exemplarily, the atomic percentage of manganese on the surface of the red phosphor particles x2% is 0%, 0.01%, 0.03%, 0.05%, 0.06%, 0.08%, 0.09%, or a range consisting of any two of the foregoing values.

[0012] In a second aspect, the present application provides a method for producing the above red phosphor, the method including the following steps (1), (2), and (3): (1) A mixed solution of the A source and an aqueous solution of hydrofluoric acid is obtained and designated as 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 content of hydrofluoric acid in the aqueous hydrofluoric acid solution is 40% by mass. (2) A mixed solution of Mn source and M source (H2MF6 hydrofluoric acid solution) is obtained and designated as BX solution. Here, the content of H2MF6 in the H2MF6 hydrofluoric acid solution is 20 mass % to 40 mass %, and the BX solution is a BX1 solution, a BX2 solution, ..., a BX n solution, n≧5 is satisfied, and the content of the Mn source is n Gradually reduce the solution to BX n The content of the Mn source in the solution is 0, That is, the BX n The content of the Mn source in the solution may or may not be 0, and the BX nWhen the content of the Mn source in the solution is 0, a manganese-free shell layer is synthesized in situ on the surface of the red phosphor particles, and the manganese-free shell layer is formed by removing the Mn present on the surface of the phosphor particles. 4+ This effectively prevents the phosphor powder from being exposed to moisture in the air, further improving the anti-aging ability of the phosphor powder. (3) BX1 solution to BX n The BX solution of step (2) is poured into the A solution of step (1) in this order, and the reaction is carried out to obtain the red phosphor.

[0013] The order of steps (1) and (2) is not limited, and solution A may be prepared first and then solution BX, or solution A may be prepared first and then solution A. This order may be selected according to the actual situation, and is not limited in the present application.

[0014] In some embodiments, in step (2), the content of the Mn source is changed from the BX1 solution to the BX n and optionally, the content of the Mn source is linearly and uniformly decreased from the BX1 solution to the BX2 solution. 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 to 50 mL / s, the injection interval is 5 to 15 minutes, and the reaction conditions are a reaction temperature of 40 to 50°C, and a reaction time of 2 to 4 hours.

[0016] In some embodiments, in step (1), the mass ratio of the A source to 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 and the M source is M2, and 0≦M2 / M1<1 is satisfied.

[0017] In a third aspect, the present application discloses the use of the above red phosphor or the red phosphor produced by the above manufacturing method in the field of LCD backlight or LED lighting.

[0018] In a fourth aspect, the present application discloses a liquid crystal backlight including 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 apparatus including a light-emitting device, the light-emitting device including an excitation chip and a phosphor coated on the excitation chip, the phosphor being 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 according to some embodiments of the present application include at least the following: In the present application, the activator Mn 4+ The concentration of Mn is distributed in a downward gradient, which buffers the erosion of the phosphor powder by water vapor and 4+ The anti-aging property is better than that of the phosphor powder of the prior art in which the concentration of the activator Mn is set without any gradient. 4+ The linear and uniformly decreasing concentration of manganese ions on the surface of the red phosphor particles contributes to improving the anti-aging properties and extending the service life of the resulting phosphor, compared to a non-linear and non-uniform distribution. Furthermore, the present invention gradually decreases 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, which is beneficial to protecting the crystal lattice of the crystal structure itself and further improving the anti-aging properties of the phosphor powder. [Brief explanation of the drawings]

[0021] In order to more clearly describe the technical solutions in the embodiments of the present application or the prior art, the following briefly introduces drawings necessary for describing the embodiments or the prior art. However, the drawings in the following description are only some embodiments of the present application, and it is obvious to those skilled in the art that other drawings can be obtained based on these drawings without any creative efforts. [Figure 1] 1 is a scanning electron microscope photograph of the K2SiF6:Mn4+ phosphor produced in Example 1 of the present application. [Figure 2] FIG. 1 is a diagram showing a new surface obtained by cutting the K2SiF6:Mn4+ phosphor produced in Example 1 using a dual-beam ion beam. [Figure 3] FIG. 1 shows the line scan path of an EDX line scan from the center A to the surface B of the K2SiF6:Mn4+ phosphor produced in Example 1. [Figure 4] FIG. 4 shows the elemental contents from EDX line scans of FIG. 3. [Figure 5] FIG. 1 is a schematic diagram of point sampling when the K2SiF6:Mn4+ phosphor prepared in Example 1 of the present application is subjected to energy spectrum analysis. [Figure 6] FIG. 6 is a schematic diagram showing the distribution curve of the relative content of Mn4+ at the spot sampling points of Examples 1 to 5, which were tested by spot sampling as in FIG. 5. DETAILED DESCRIPTION OF THE INVENTION

[0022] In order to make the objectives, technical solutions and advantages of the present application clearer, the present 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 only used to illustrate the present application and are not intended to limit the present application.

[0023] The present invention will be further illustrated by the following examples, in which all other fluorescent materials used in the examples are commercially available.

[0024] Manufacturing of KSF phosphor (K2SiF6:Mn 4+ (Production)

[0025] Example 1 (1) Preparation of BX solutions: 2.7 g, 2.52 g, 2.34 g, 2.16 g, 1.98 g, 1.80 g, 1.62 g, 1.44 g, 1.26 g, 1.08 g, 0.9 g, 0.72 g, 0.54 g, 0.36 g, 0.18 g, and 0 g of K2MnF6 were weighed and dissolved in 50 g of commercially available 30% to 32% HSF (i.e., 30% to 32% aqueous fluorosilicic acid solution), respectively, to prepare BX1 solution (containing 2.7 g of K2MnF6), BX2 solution, ..., BX 16 Sixteen sets of BX solutions corresponding sequentially to the solutions (containing no K2MnF6) were obtained. (2) Preparation of Solution A: 21 g of potassium hydrogen fluoride was weighed and dissolved in 250 ml of a 40% aqueous HF solution (ie, a 40% aqueous hydrofluoric acid solution) to obtain Solution A. (3) BX1 solution to BX 16 The prepared BX solution was injected into solution A at an injection rate of 10 mL / s at intervals of 6 minutes, followed by stirring at 40°C for 2 hours and then allowing to stand for separation. (4) Post-treatment: The supernatant was discarded, and 5% HF aqueous solution (5% hydrofluoric acid aqueous solution) was added, washed by stirring twice, washed twice with absolute ethanol, and baked by blowing air at 60°C to dry. The median diameter of the KSF phosphor produced in Example 1 was 30 μm. FIG. 1 shows the K2SiF6:Mn 4+ 1 is a scanning electron microscope photograph of the phosphor. As can be seen from FIG. 1, the K2SiF6:Mn 4+ The phosphor has a nearly spherical shape. 4+ FIG. 3 shows a new surface of the phosphor cut by a dual-beam ion beam. 4+FIG. 4 is a diagram showing the line scanning path of the EDX line scanning from the center A to the surface B of the phosphor. FIG. 4 is a schematic diagram showing the element content by the EDX line scanning of FIG. 3. The ordinate CPS of FIG. 4 indicates that the count has no special physical meaning and represents the signal intensity of the detected element. FIG. 5 shows the K2SiF6:Mn 4+ FIG. 6 is a schematic diagram of point sampling when subjecting a phosphor to energy spectrum analysis. FIG. 6 shows the Mn at the point sampling locations of Example 1 tested by point sampling as in FIG. 4+ 6 is a schematic diagram showing the distribution curve of the relative content of K2SiF6:Mn 4+ The concentration of tetravalent manganese ions in the radial direction from the center of the red phosphor particle to its surface decreased linearly and uniformly to zero.

[0026] Example 2 (1) Preparation of BX solutions: 2.7 g, 2.23 g, 1.87 g, 1.57 g, 1.34 g, 1.14 g, 0.95 g, 0.74 g, 0.59 g, 0.46 g, 0.34 g, 0.22 g, 0.15 g, 0.07 g, 0.03 g, and 0 g of K2MnF6 were weighed and dissolved in 50 g of commercially available 30% to 32% HSF, respectively, to produce BX1 solution (containing 2.7 g of K2MnF6), BX2 solution, ..., BX 16 Sixteen sets of BX solutions corresponding sequentially to the solutions (containing no K2MnF6) were obtained. (2) Preparation of Solution A: 21 g of potassium hydrogen fluoride was weighed and dissolved in 250 ml of a 40% aqueous HF solution to obtain Solution A. (3) BX1 solution to BX 16 The prepared BX solution was injected into solution A at an injection rate of 15 mL / s at 10-minute intervals, and the mixture was stirred at 50°C for 4 hours, then allowed to stand and separated. (4) Post-treatment: The supernatant was discarded, and 5% aqueous HF solution was added, followed by washing with stirring twice, washing twice with absolute ethanol, and baking at 60°C by blowing air to dry. The median diameter of the KSF phosphor produced in Example 2 was 30 μm. As can be seen from FIG. 6, the concentration of tetravalent manganese ions in the radial direction from the center to the surface of the red phosphor particle produced in Example 2 decreased nonlinearly to zero.

[0027] Example 3 (1) Preparation of BX solutions: 2.7 g, 1.77 g, 1.27 g, 1.00 g, 0.79 g, 0.61 g, 0.48 g, 0.39 g, 0.30 g, 0.23 g, 0.17 g, 0.12 g, 0.08 g, 0.04 g, 0.02 g, and 0 g of K2MnF6 were weighed and dissolved in 50 g of commercially available 30% to 32% HSF, respectively, to produce BX1 solution (containing 2.7 g of K2MnF6), BX2 solution, ..., BX 16 Sixteen sets of BX solutions corresponding sequentially to the solutions (containing no K2MnF6) were obtained. (2) Preparation of Solution A: 21 g of potassium hydrogen fluoride was weighed and dissolved in 250 ml of a 40% aqueous HF solution to obtain Solution A. (3) BX1 solution to BX 16 The prepared BX solution was injected into solution A at an injection rate of 35 mL / s at intervals of 13 minutes, followed by stirring at 45°C for 3 hours and then allowing to stand for separation. (4) Post-treatment: The supernatant was discarded, and 5% aqueous HF solution was added, followed by washing with stirring twice, washing twice with absolute ethanol, and baking at 60°C by blowing air to dry. The median diameter of the KSF phosphor produced in Example 3 was 30 μm. As can be seen from FIG. 6, the concentration of tetravalent manganese ions in the radial direction from the center to the surface of the red phosphor particle produced in Example 3 decreased nonlinearly and nonuniformly to zero.

[0028] Example 4 (1) Preparation of BX solutions: 2.7 g, 2.65 g, 2.6 g, 2.52 g, 2.43 g, 2.37 g, 2.24 g, 2.07 g, 1.91 g, 1.76 g, 1.57 g, 1.38 g, 1.16 g, 0.86 g, 0.52 g, and 0 g of K2MnF6 were weighed and dissolved in 50 g of commercially available 30% to 32% HSF, respectively, to produce BX1 solution (containing 2.7 g of K2MnF6), BX2 solution, ..., BX 16Sixteen sets of BX solutions corresponding sequentially to the solutions (containing no K2MnF6) were obtained. (2) Preparation of Solution A: 21 g of potassium hydrogen fluoride was weighed and dissolved in 250 ml of a 40% aqueous HF solution to obtain Solution A. (3) BX1 solution to BX 16 The prepared BX solution was injected into solution A at an injection rate of 50 mL / s at 15-minute intervals in the order of the solutions, and the mixture was stirred at 45°C for 4 hours, then allowed to stand and separated. (4) Post-treatment: The supernatant was discarded, and 5% aqueous HF solution was added, followed by washing with stirring twice, washing twice with absolute ethanol, and baking at 60°C by blowing air to dry. The median diameter of the KSF phosphor produced in Example 4 was 30 μm. As can be seen from FIG. 6, the concentration of tetravalent manganese ions in the radial direction from the center to the surface of the red phosphor particle produced in Example 4 decreased nonlinearly to zero.

[0029] Example 5 (1) Preparation of BX solutions: 2.7 g, 2.69 g, 2.68 g, 2.68 g, 2.66 g, 2.63 g, 2.58 g, 2.51 g, 2.40 g, 2.25 g, 2.05 g, 1.81 g, 1.58 g, 1.32 g, 0.89 g, and 0 g of K2MnF6 were weighed and dissolved in 50 g of commercially available 30% to 32% HSF, respectively, to produce BX1 solution (containing 2.7 g of K2MnF6), BX2 solution, ..., BX 16 Sixteen sets of BX solutions corresponding sequentially to the solutions (containing no K2MnF6) were obtained. (2) Preparation of Solution A: 21 g of potassium hydrogen fluoride was weighed and dissolved in 250 ml of a 40% aqueous HF solution to obtain Solution A. (3) BX1 solution to BX 16 The prepared BX solution was injected into solution A at an injection rate of 10 mL / s at intervals of 6 minutes in the order of the solutions, and the mixture was stirred at 45°C for 2 hours, then allowed to stand and separated. (4) Post-treatment: The supernatant was discarded, and 5% aqueous HF solution was added, followed by washing with stirring twice, washing twice with absolute ethanol, and baking at 60°C by blowing air to dry. The median diameter of the KSF phosphor produced in Example 5 was 30 μm. As can be seen from FIG. 6, the concentration of tetravalent manganese ions in the radial direction from the center to the surface of the red phosphor particle produced in Example 5 decreased nonlinearly and nonuniformly to zero.

[0030] [Table 1]

[0031] Manufacturing of other phosphors

[0032] Example 1 (1) In an ice-water bath, 150 g of germanium oxide GeO2 was added to 850 g of a 50% aqueous solution of hydrofluoric acid, and the mixture was mechanically stirred for 1 hour to obtain a 30% by mass solution of fluorogermanic acid H2GeF6. (2) Preparation of BX solutions: 2.7 g, 2.52 g, 2.34 g, 2.16 g, 1.98 g, 1.80 g, 1.62 g, 1.44 g, 1.26 g, 1.08 g, 0.9 g, 0.72 g, 0.54 g, 0.36 g, 0.18 g, and 0 g of K2MnF6 were weighed and dissolved in 50 g of 30% by mass homemade fluorogermanic acid, respectively, to produce BX1 solution (containing 2.7 g of K2MnF6), BX2 solution, ..., BX 16 Sixteen sets of BX solutions corresponding sequentially to the solutions (containing no K2MnF6) were obtained. (3) Preparation of Solution A: 21 g of potassium hydrogen fluoride was weighed and dissolved in 250 ml of a 40% aqueous HF solution (ie, a 40% aqueous hydrofluoric acid solution) to obtain Solution A. (4) BX1 solution to BX 16 The prepared BX solution was injected into solution A at an injection rate of 10 mL / s at intervals of 6 minutes, followed by stirring at 40°C for 2 hours and then allowing to stand for separation. (5) Post-treatment: The supernatant was discarded, and a 5% aqueous HF solution was added (5% aqueous hydrofluoric acid solution), washed twice with stirring, washed twice with absolute ethanol, and baked at 60°C by blowing air to dry. K2Ge produced in Example 1 (1-x) F6:xMn 4+ The median diameter of the phosphor was 30 μm.

[0033] Example 2 (1) In an ice-water bath, 146 g of titanium dioxide TiO2 was added to 854 g of a 50% aqueous solution of hydrofluoric acid, and the mixture was mechanically stirred for 1 hour to obtain a 30% by mass solution of fluorogermanic acid H2TiF6. (2) Preparation of BX solutions: 2.7 g, 2.52 g, 2.34 g, 2.16 g, 1.98 g, 1.80 g, 1.62 g, 1.44 g, 1.26 g, 1.08 g, 0.9 g, 0.72 g, 0.54 g, 0.36 g, 0.18 g, and 0 g of K2MnF6 were weighed and dissolved in 50 g of 30% by mass homemade fluorotitanic acid, respectively, to produce BX1 solution (containing 2.7 g of K2MnF6), BX2 solution, ..., BX 16 Sixteen sets of BX solutions corresponding sequentially to the solutions (containing no K2MnF6) were obtained. (3) Preparation of Solution A: 21 g of potassium hydrogen fluoride was weighed and dissolved in 250 ml of a 40% aqueous HF solution (ie, a 40% aqueous hydrofluoric acid solution) to obtain Solution A. (4) BX1 solution to BX 16 The prepared BX solution was injected into solution A at an injection rate of 10 mL / s at intervals of 6 minutes, followed by stirring at 40°C for 2 hours and then allowing to stand for separation. (5) Post-treatment: The supernatant was discarded, and a 5% HF aqueous solution (5% hydrofluoric acid aqueous solution) was added, washed by stirring twice, washed twice with absolute ethanol, and baked at 60°C by blowing air to dry. 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-water bath, 344 g of germanium oxide GeO2 was added to 656 g of a 50% aqueous solution of hydrofluoric acid, and the mixture was mechanically stirred for 1 hour to obtain a 30% by mass solution of fluorogermanic acid H2GeF6. (2) Preparation of BX solutions: 2.35 g, 2.19 g, 2.04 g, 1.88 g, 1.72 g, 1.57 g, 1.41 g, 1.25 g, 1.10 g, 0.94 g, 0.78 g, 0.63 g, 0.47 g, 0.31 g, 0.16 g, and 0 g of Na2MnF6 were weighed and dissolved in 50 g of 30% by mass of homemade fluorogermanic acid, respectively, to produce BX1 solution (containing 2.35 g of Na2MnF6), BX2 solution, ..., BX 16 Sixteen sets of BX solutions corresponding sequentially to the solutions (without Na2MnF6) were obtained. (3) Preparation of Solution A: 16.6 g of sodium fluoride was weighed and dissolved in 250 ml of a 40% aqueous HF solution (ie, a 40% aqueous hydrofluoric acid solution) to obtain Solution A. (4) BX1 solution to BX 16 The prepared BX solution was injected into solution A at an injection rate of 10 mL / s at intervals of 6 minutes, followed by stirring at 40°C for 2 hours and then allowing to stand for separation. (5) Post-treatment: The supernatant was discarded, and a 5% HF aqueous solution (5% hydrofluoric acid aqueous solution) was added, washed by stirring twice, washed twice with absolute ethanol, and baked at 60°C by blowing air to dry. Na2Ge produced in Example 3 (1-x) F6:xMn 4+ The median diameter of the phosphor was 30 μm.

[0035] Energy Spectrum Analysis Test The KSF phosphors prepared in Examples 1 to 5 were cut using a dual ion beam, and 16 points were taken at equal intervals from the center A of the new surface to the surface B for energy spectrum analysis. As shown in Figure 5, Figure 5 is a schematic diagram of the point collection when the KSF phosphor prepared in Example 1 is subjected to energy spectrum analysis, and the Mn atomic percentages at the point collection points are shown in Table 2 and Figure 6. The point collection method for the KSF phosphors prepared in Examples 2 to 5 can be referenced to the point collection method of Example 1 in Figure 5, and the Mn atomic percentages at the point collection points are shown in Table 2 and Figure 6, and will not be described again here.

[0036] [Table 2]

[0037] As can be seen from Table 2 and FIG. 6, the red phosphor particles manufactured in Examples 1 to 5 have a gradual decrease in the concentration of tetravalent manganese ions in the radial direction from the center to the surface. 4+ From the decreasing trend of the concentration of Mn in Example 1, 4+ The concentration of Mn in Examples 2 to 5 decreased linearly and uniformly in the radial direction from the center of the particle to its surface, especially like an arithmetic progression, and the decreasing trend was a straight line, with the distance between two adjacent points on the line being equal. 4+ The concentration of Mn on the particle surface in Examples 1 to 5 decreases non-uniformly in the radial direction from the center to the surface, and the decreasing trend is curvilinear. 4+ The concentrations of both were found to be 0.

[0038] Example 6 When preparing BX solution, BX1 solution is used to 10 Only the solution was prepared, i.e., the KSF phosphor prepared in Example 6 was the same as in Example 1, except that the ratio x2 / x1 of the atomic percent manganese content x2 at its surface to the atomic percent manganese content x1 at its center was 0.395.

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

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

[0041] Comparative Example 1 The BX solution was prepared in the same manner as in Example 1, except that all K2MnF6 was added directly to 10%-15% HSF, i.e., not added in a descending gradient. Specifically, 21.6 g of K2MnF6 was weighed out and dissolved in 800 g of commercially available 10%-15% HSF, and the solution was divided into 16 equal parts, BX1 to BX2, each with the same K2MnF6 content. 16 A solution is obtained, and then, 16 The solutions were injected into solution A sequentially at an injection rate of 10 mL / s with an interval of 6 min, and the rest was the same as in Example 1. Table 3 shows the test method and equipment for the 1000-hour aging test in this application, and Table 4 shows the aging test data for the phosphors produced in Examples 1 to 8, Examples 1 and 2, and Comparative Example 1 (Explanation: KSF-0 is the sample of Comparative Example 1, KSF-1 is the sample of Example 1, KSF-2 is the sample of Example 2, KSF-3 is the sample of Example 3, KSF-4 is the sample of Example 4, KSF-5 is the sample of Example 5, KSF-6 is the sample of Example 6, KSF-7 is the sample of Example 7, KSF-8 is the sample of Example 8, KSF-9 is the sample of Example 1, KSF-10 is the sample of Example 2, and KSF-11 is the sample of Example 3).

[0042] [Table 3]

[0043] [Table 4]

[0044] Combining the data in Table 4, it can be seen 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, in which the concentration of tetravalent manganese ions was not gradient-graded, the luminous flux value at 0 h was 128.30 lm, and the luminous flux value after 1000 h of use was only 123.56 lm, a decrease of 4.74 lm. Furthermore, the brightness of the phosphor produced in Comparative Example 1 significantly decreased from the initial 100% to 96.2% after 1000 h of use. However, in Example 1 described herein, in which the concentration of tetravalent manganese ions was gradient-graded along the radial direction, the luminous flux after 1000 h of use decreased by 1.16 lm compared to the luminous flux at 0 h. The brightness ratio of the phosphor produced in Example 1 reached 99.1% even after 1000 h of use. This indicates that the phosphor with a gradient-graded concentration of tetravalent manganese ions has a long service life. Comparing KSF-2 to KSF-5 with KSF-1, the concentration of tetravalent manganese ions decreases linearly and uniformly in the radial direction from the center of the phosphor particle to the surface, which is advantageous for improving the phosphor's anti-aging properties and also enhances its ability to retard erosion by water vapor.

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

[0046] It is understood that the above embodiment is merely an example of an embodiment adopted to explain the principle of the present invention, but the present invention is not limited thereto. Those skilled in the art can make various modifications and improvements without departing from the spirit and essence of the present invention, and these modifications and improvements are deemed to be within the protection scope of the present invention.

Claims

1. A red phosphor, wherein the red phosphor is any one selected from substances represented by formula I, A ２ M （１－ｘ） F ６ : xMn ４＋ Formula I In formula I, A is at least one selected from alkali metal elements, M is at least one element selected from the group 4 elements and Ti element, The value of x is in the range of 0<x≦0.05; the red phosphor is in particulate form, A red phosphor, wherein the concentration of tetravalent manganese ions gradually decreases in the radial direction from the center of the red phosphor particle to the surface thereof.

2. In formula I, A is at least one element selected from the group consisting of Na and K, and / or 2. The red phosphor according to claim 1, wherein M is at least one element selected from the group consisting of Si, Ge, and Ti.

3. 2. The red phosphor according to claim 1, wherein the concentration of tetravalent manganese ions decreases linearly and uniformly in the radial direction from the center of the red phosphor particle to its surface.

4. 2. The red phosphor according to claim 1, wherein the concentration of tetravalent manganese ions on the surface of the red phosphor particles is zero.

5. The percentage content of manganese atoms at the center of the red phosphor particle is x １ %, and the percentage content of manganese atoms on the surface of the red phosphor particle is x ２ %, 0≦x ２ / x １ 2. The red phosphor according to claim 1, wherein the red phosphor satisfies the following relationship:

6. 0≦x ２ / x １ 6. The red phosphor according to claim 5, wherein the red phosphor satisfies a value of ≦0.

33.

7. The percentage content of manganese atoms at the center of the red phosphor particle is x １ %, 0.1≦x １ 6. The red phosphor according to claim 5, wherein the red phosphor satisfies a value of ≦5.

8. The percentage content of manganese atoms at the center of the red phosphor particle is x １ %, 0.5≦x １ 8. The red phosphor according to claim 7, wherein the red phosphor satisfies the following condition: ≦1.

9. The percentage content of manganese atoms on the surface of the red phosphor particle is x ２ %, 0≦x ２ 6. The red phosphor according to claim 5, wherein the red phosphor satisfies a value of 0.1 or less.

10. Step (1) of obtaining a mixed solution of an A source and an aqueous hydrofluoric acid solution to form an A solution; Step (2) of obtaining a mixed solution of a Mn source and an M source to form a BX solution, The BX solution is １ solution, BX ２ Solution, ..., BX ｎ The solution contains n≧5, and the content of the Mn source is １ From the solution ｎ The solution gradually decreases Optionally, said BX ｎ Step (2), in which the content of the Mn source in the solution is 0; BX １ BX from the solution ｎ and step (3) of sequentially injecting the BX solution of step (2) into the A solution of step (1) in the order of the solutions, and reacting them to obtain the red phosphor.

11. In step (2), the content of the Mn source is １ From the solution ｎ linearly and uniformly decreases until solution Optionally, the content of the Mn source is １ From the solution ｎ 11. The method according to claim 10, wherein the solution is uniformly reduced in an arithmetic progression.

12. In step (3), the injection rate of the BX solution is 10 to 50 mL / s, and the injection interval is 5 to 15 minutes; The method according to claim 10, wherein the reaction conditions are a reaction temperature of 40 to 50°C and a reaction time of 2 to 4 hours.

13. In step (1), the mass ratio of the A source to hydrofluoric acid is 20 to 25:95 to 105; In step (2), the BX １ In the solution, the molar percentage of the Mn source and the M source is M １ and the BX ｎ In the solution, the molar percentage of the Mn source and the M source is M ２ and 0≦M ２ / M １ The method according to claim 10, characterized in that <1 is satisfied.

14. Use of the red phosphor according to any one of claims 1 to 9 or the red phosphor produced by the production method according to any one of claims 10 to 13 in the field of liquid crystal backlights or LED lighting.

15. An excitation chip and a phosphor coated on the excitation chip, The phosphor is a red phosphor according to any one of claims 1 to 9, or 14. A liquid crystal display backlight, wherein the phosphor is a red phosphor produced by the production method according to claim 10.

16. a light emitting device; the light-emitting device includes an excitation chip and a phosphor coated on the excitation chip; The phosphor is a red phosphor according to any one of claims 1 to 9, or 14. A lighting device, wherein the phosphor is a red phosphor produced by the method according to claim 10.

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