Fluorosilicate fluorescent single crystal material with high Mn < 4 + > content as well as preparation method and application of fluorosilicate fluorescent single crystal material

Abstract

The invention belongs to the technical field of luminescent functional materials, and discloses a fluorosilicate fluorescent single crystal material with high Mn < 4 + > content as well as a preparation method and application thereof, and the chemical composition of the fluorosilicate fluorescent single crystal material is A2Si1-nMnnF6, wherein A is one or a combination of two of alkali metals Rb and Cs, n is a molar ratio of Mn < 4 + > ions to the total amount of Mn < 4 + > and Si < 4 + > ions, and n is more than 0 and less than or equal to 1. The red light single crystal material is prepared through a component regulation and control single crystal method, the method is simple and easy to implement and mild in condition, the obtained red light single crystal material is complete in single crystal morphology and controllable in size, 20-60% high manganese content solid solution is achieved, the disadvantage that the quenching concentration of typical fluorides is low is broken through, the red light single crystal material can be well matched with various LED devices such as ultraviolet light, purple light and blue light, and the red light single crystal material has good application prospects. The external quantum efficiency is obviously improved to 40-80%, and the color gamut of a packaged LED device reaches 106% NTSC.

Description

Technical Field

[0001] This invention belongs to the field of luminescent functional materials technology, and relates to a high Mn content material. 4+ Fluorosilicate fluorescent single crystal materials with high content, their preparation methods and applications. Background Technology

[0002] Mn 4+ Red fluorescent materials doped with all-inorganic fluorides have been a focus of attention in the past decade. In 2008, Sadao Adachi, a scientist at Gunma University in Japan, synthesized MnO2-doped red fluorescent materials in an HF solution etching experiment on silicon wafers. 4+ Activated K₂SiF₆ red-emitting materials exhibit broad-spectrum absorption in the near-ultraviolet and blue light regions, and can emit narrow-band red light with high color purity (J. Appl. Phys., 2008, 104, 023512). This type of Mn... 4+ Activated fluoride red phosphors can be effectively excited by commercially available blue LED chips, offering advantages such as high color purity, high luminous efficiency, simple preparation process, and absence of rare earth elements. This contrasts with traditional Eu... 2+ The market for doped nitride red phosphors has been significantly impacted, and they are now widely used in blue-excited white LED lighting and display devices. Due to Mn... 4+ In an intermediate valence state, it is easily oxidized and reduced at high temperatures, therefore this type of Mn 4+ Activated fluorides are often synthesized using room temperature or low-temperature liquid-phase methods, with common techniques including chemical etching, ion exchange, and co-precipitation to synthesize phosphors. Currently, Mn synthesized using these methods... 4+ Activating fluorides still faces the challenge of low quenching concentrations, with a quenching molar concentration of only c(Mn) ≤ 5%. This results in the excitation range not covering the 400 nm violet region, hindering its application in emerging violet-excited full-spectrum lighting and other applications. Furthermore, the low quenching concentration leads to low external quantum efficiency (EQE) of the phosphor material, < 60%, making it difficult to achieve high luminous efficiency in devices. Therefore, there is an urgent need to develop synthesis methods to achieve Mn... 4+ The high quenching concentration is used to achieve the goal of expanding the absorption range and high quantum efficiency. Summary of the Invention

[0003] To overcome the shortcomings and deficiencies of existing technologies, the primary objective of this invention is to provide a high Mn content... 4+ Fluorosilicate fluorescent single crystal materials;

[0004] Another object of the present invention is to provide a high Mn 4+ Preparation method of fluorosilicate fluorescent single crystal materials with high content;

[0005] Another object of the present invention is to provide a high Mn 4+ Applications of high-content fluorosilicate fluorescent single crystal materials.

[0006] The objective of this invention is achieved through the following technical solution:

[0007] A high Mn 4+ Fluorosilicate fluorescent single crystal material with the chemical formula A2Si 1-n Mn n F6;

[0008] Wherein, A is one or a combination of two alkali metals Rb and Cs;

[0009] n is Mn 4+ Ions relative to Mn 4+ and Si 4+ The molar ratio of the total amount of ions, 0 < n ≤ 1.

[0010] Preferably, the range of n is 0.02 ≤ n ≤ 0.60;

[0011] The high Mn 4+ The fluorosilicate fluorescent single crystals are cubic with a single crystal size of 10–900 μm.

[0012] Preferably, the high Mn 4+ Fluorosilicate fluorescent single crystal materials exhibit multi-peak sharp-line narrow-spectrum red light emission at ~630 nm under ultraviolet, violet, or blue light excitation.

[0013] Preferably, for components with low manganese content, i.e., n = 0.02 to 0.25, there is absorption in the blue and ultraviolet light regions, which can be effectively excited by ultraviolet or blue light chips; for components with high manganese content, i.e., n = 0.25 to 1, the absorption peak is broadened, which can be effectively excited by ultraviolet, violet, and blue light chips.

[0014] Preferably, for the low manganese content component, i.e., n = 0.02–0.25, its red light emission has an external quantum efficiency of 40–65%; for the high manganese content component, i.e., n = 0.25–0.60, its red light emission has an external quantum efficiency of 40–80%.

[0015] Preferably, the high Mn content is at 300K-400K. 4+ The Helmholtz free energy ΔF(n,T) ≤ 0 for fluorosilicate fluorescent single crystal materials indicates that the luminescent center Mn 4+ Continuous solid solution in the material structure is a way to avoid phase separation and achieve high Mn content. 4+ The prerequisite for fluoride content.

[0016] Preferably, the high Mn 4+Fluorosilicate fluorescent single-crystal materials exhibit complete single-crystal morphology, high transparency, few surface defects, and low surface energy. Compared to powder (polycrystalline cluster) morphology samples, they ensure fewer quenching centers, achieving high Mn content. 4+ Concentration without quenching.

[0017] Preferably, the high Mn 4+ Fluorosilicate fluorescent single-crystal materials were prepared by a composition-controlled single-crystal method. This method allows for the design of solid solution structures and micron-scale single-crystal morphologies, overcoming the limitations of traditional Mn methods. 4+ Despite the drawbacks of low doping content and quenching concentration, it is possible to achieve micron-level high concentrations of Mn. 4+ The synthesis and preparation of activated fluoride fluorescent single crystals are simple and easy to carry out under mild conditions, and can be mass-produced industrially.

[0018] A high Mn 4+ The preparation method of fluorosilicate fluorescent single crystal materials includes the following steps:

[0019] S1. Preparation of Mn-containing precursors via ion exchange reaction;

[0020] S2. Under stirring conditions, dissolve the silicon component raw material, alkali metal raw material, and Mn-containing precursor in hydrofluoric acid solution. Add hydrofluoric acid solution until saturated to obtain a reaction solution. Filter the reaction solution, let it stand, and crystals precipitate out as the solution becomes supersaturated; these are high-Mn crystals. 4+ Fluorosilicate fluorescent single crystal materials.

[0021] Preferably, the specific steps of S1 are as follows: dissolve excess RbF and / or CsF in hydrofluoric acid solution, add K2MnF6 to carry out ion exchange reaction, and then wash and dry to obtain the Mn-containing precursor.

[0022] Preferably, the preparation method of K2MnF6 is as follows: KF or KHF2 is dissolved in hydrofluoric acid solution according to the stoichiometric ratio of the chemical formula of K2MnF6, and permanganate KMnO4 is added. After complete dissolution, the mixed solution is cooled to below 5°C in an ice bath, and then hydrogen peroxide is added dropwise until the solution changes from purple to yellow. The addition is stopped immediately and the solution is filtered. The resulting precipitate is washed and dried to obtain fluoromanganate K2MnF6.

[0023] The Mn precursor is either cubic Cs2MnF6 or cubic Rb2MnF6.

[0024] Preferably, the silicon component raw material in S2 is selected from one or more of H2SiF6 solution, K2SiF6, or SiO2;

[0025] The alkali metal raw material is selected from one or a combination of two of RbF, RbCl, Rb2CO3 or CsF;

[0026] Preferably, the filtration in step S2 is through a 0.22μm filter, and the settling temperature is room temperature.

[0027] Preferably, the ratio of Si and Mn raw materials is adjusted to adjust the component parameter n;

[0028] The ratio of the molar content of manganese in the Mn-containing precursor to the sum of the molar content of manganese in the Mn-containing precursor and the molar content of silicon in the silicon component raw material is 0 to 1, preferably 0.02 to 0.60.

[0029] The concentration of the H2SiF6 solution is 20–40 wt%; the concentration of the hydrofluoric acid solution is 40–60 wt%.

[0030] The above-mentioned high Mn 4+ Application of high-content fluorosilicate fluorescent single crystal materials in LED devices.

[0031] A wide color gamut device, comprising the aforementioned high Mn 4+ Fluorosilicate fluorescent single crystal materials, light-emitting diodes, and phosphors are encapsulated into white LED devices;

[0032] The light-emitting diode is an ultraviolet, near-ultraviolet, violet, or blue light-emitting diode;

[0033] The phosphor is β-SiAlON:Eu 2+ Green fluorescent powder.

[0034] Preferably, the white LED device has a color temperature of 5000–7000K and a color rendering index ≥90; the wide color gamut device has a color gamut of 106% NTSC and a luminous efficacy of 125.4 lm / W.

[0035] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0036] (1) Mn of the present invention 4+ The preparation method for activated fluoride red light materials is a composition-controlled single-crystal method. Through continuous solid solution structure design and single-crystal morphology design, high Mn content can be achieved. 4+ Quenching concentration. Compared with traditional synthesis methods such as wet chemical etching and coprecipitation, the preparation process of this invention is simple and easy to implement, with mild conditions, and can effectively control the morphology of the product, synthesizing uniform single crystals, which can be mass-produced industrially.

[0037] (2) Mn of the present invention 4+The activated fluorosilicate fluorescent single-crystal material exhibits complete single-crystal morphology, tunable size within the 10–900 micrometer range, high transparency, few surface defects, and low surface energy. Compared to powder (polycrystalline cluster) morphology samples, it ensures fewer quenching centers, achieving a high manganese content solid solution of 20–60%, overcoming the disadvantage of low quenching concentration (around 4%) in typical materials. Its external quantum efficiency for red light emission can reach 40–80%, making it a high-manganese-concentration, wide-absorption-range, and high-quantum-efficiency Mn2+ material. 4+ Activate fluoride fluorescent materials.

[0038] (3) The application scope of the fluorosilicate fluorescent single crystal material of the present invention is extended to ultraviolet, violet, and blue LEDs and laser devices, and can significantly improve the luminous efficacy of the devices. The color rendering index of the packaged violet laser-excited lighting device is as high as 91.0, and the color gamut of the packaged wide color gamut LED device reaches 106% NTSC, with a luminous efficacy of up to 125.4 lm / W, which has important application value. Attached Figure Description

[0039] Figure 1 The X-ray diffraction pattern of the single crystal sample involved in Example 5;

[0040] Figure 2 This is a schematic diagram of the refined structure of the single crystal sample involved in Example 5;

[0041] Figure 3 Images and size-frequency distribution diagrams of the single crystal involved in Example 5;

[0042] Figure 4 The values ​​are the calculated Gibbs free energies of the components involved in Examples 1 to 8;

[0043] Figure 5 The photoluminescence excitation spectra of the fluorescent single crystals involved in Examples 2, 5, and 7 are shown.

[0044] Figure 6 This is a quantum efficiency test graph of the fluorescent single crystal material involved in Example 5 under 460nm excitation, where BG is a barium sulfate background test.

[0045] Figure 7 The quantum efficiency test graph of the fluorescent single crystal material involved in Example 9 under 460nm excitation is shown, where BG is the barium sulfate background test.

[0046] Figure 8 The photoluminescence spectra of the fluorescent single crystals involved in Examples 5 and 9 are shown.

[0047] Figure 9 The chromaticity coordinates of the fluorescent single crystals involved in Examples 5 and 9;

[0048] Figure 10The spectrum of the laser illumination device involved in Example 10;

[0049] Figure 11 The spectrum of the white LED backlight device involved in Example 11 is shown below.

[0050] Figure 12 Micrographs of the crystals synthesized in Examples 1 and 4-8;

[0051] Figure 13 This is a photomicrograph of the crystal synthesized in Comparative Example 1 under blue light irradiation. Detailed Implementation

[0052] The technical solutions of the present invention will be further described below with reference to specific embodiments and accompanying drawings. However, the following embodiments are only for enhancing the illustration of the technical solutions of the present invention and should not be construed as any limitation on the scope of the claimed invention. Furthermore, the described embodiments are merely some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, any modifications, equivalent substitutions, improvements, etc., made by those skilled in the art without creative effort to obtain all other embodiments should be included within the protection scope of the present invention. For process parameters not specifically specified, conventional techniques can be referred to.

[0053] In a specific embodiment of the present invention, Mn 4+ Activated fluorosilicate single crystals were prepared using a composition-controlled single crystal synthesis method. The preparation process of the manganese-containing precursor used included the following steps:

[0054] According to the stoichiometric ratio of the chemical formula for fluoromanganate K2MnF6, KF or KHF2 was dissolved in a 49 wt% hydrofluoric acid solution, and permanganate KMnO4 was added. After complete dissolution, the mixed solution was cooled to below 5°C in an ice bath, and then 30 wt% hydrogen peroxide was gradually added dropwise until the solution changed from purple to yellow. The addition was stopped immediately, and the solution was filtered. The resulting precipitate was washed with acetone and dried at 80°C for 2 hours to obtain fluoromanganate K2MnF6. Excess CsF or RbF was dissolved in hydrofluoric acid solution, and K2MnF6 was added to carry out an ion exchange reaction. After washing and drying, the manganese-containing precursor—bright yellow powder Cs2MnF6 or Rb2MnF6—was obtained. To verify the application effect, the optimized sample was used for packaging lighting and display devices.

[0055] Example 1

[0056] Synthesis of A2Si 1-n Mn nF6 single crystal, composition A = Rb, n = 0, i.e., Rb₂SiF₆. 4.0 mL of 30 wt% H₂SiF₆ solution and 2.089 g of RbF were dissolved in 20 mL of 49 wt% HF solution under stirring, and HF solution was added dropwise until saturation. The reaction solution was filtered through a 0.22 μm filter (to reduce solid residue) and placed in a polystyrene petri dish. After standing at room temperature for 36 hours, colorless and transparent crystals precipitated from the supersaturated solution, which is the Rb₂SiF₆ single crystal material.

[0057] Example 2

[0058] Synthesis of A2Si 1-n Mn n F6, component A = Rb, n = 0.02, c(Mn) = 2%, i.e., Rb₂Si 0.98 Mn 0.02 F6 single crystals. 3.9 mL of 30 wt% H₂SiF₆ solution, 2.047 g of RbF, and 0.06797 g of Rb₂MnF₆ were dissolved in 20 mL of 49 wt% HF solution under stirring, with HF solution added dropwise until saturation. The reaction solution was filtered through a 0.22 μm filter (to reduce solid residue) and placed in a polystyrene petri dish. After standing at room temperature for 36 hours, the solution became supersaturated, and pale yellow transparent crystals precipitated, i.e., Rb₂SiF₆. 0.98 Mn 0.02 F6 single crystal material.

[0059] Example 3

[0060] Synthesis of A2Si 1-n Mn n F6 single crystal, composition A = Rb, n = 0.1, c(Mn) = 10%, i.e., Rb₂Si 0.9 Mn 0.1 F6. Dissolve 3.9 mL of 30 wt% H₂SiF₆ solution, 1.880 g of RbF, and 0.3399 g of Rb₂MnF₆ in 20 mL of 49 wt% HF solution with stirring, and add HF solution dropwise until saturated. Filter the reaction solution through a 0.22 μm filter (to reduce solid residue), place it in a polystyrene petri dish, and let it stand at room temperature for 36 hours. The solution becomes supersaturated, and orange transparent crystals precipitate, i.e., Rb₂Si. 0.9 Mn 0.1 F6 single crystal material.

[0061] Example 4

[0062] Synthesis of A2Si 1-n Mn n F6 single crystal, composition A = Rb, n = 0.2, c(Mn) = 20%, i.e., Rb₂Si 0.8 Mn 0.2F6. Dissolve 3.2 mL of 30 wt% H₂SiF₆ solution, 1.671 g of RbF, and 0.6797 g of Rb₂MnF₆ in 20 mL of 49 wt% HF solution with stirring, and add HF solution dropwise until saturated. Filter the reaction solution through a 0.22 μm filter (to reduce solid residue), place it in a polystyrene petri dish, and let it stand at room temperature for 36 hours. The solution becomes supersaturated, and orange transparent crystals precipitate, i.e., Rb₂Si. 0.8 Mn 0.2 F6 single crystal material.

[0063] Example 5

[0064] Synthesis of A2Si 1-n Mn n F6 single crystal, composition A = Rb, n = 0.3, c(Mn) = 30%, i.e., Rb₂Si 0.7 Mn 0.3 F6. Dissolve 2.8 mL of 30 wt% H₂SiF₆ solution, 1.462 g of RbF, and 1.020 g of Rb₂MnF₆ in 20 mL of 49 wt% HF solution with stirring, and add HF solution dropwise until saturated. Filter the reaction solution through a 0.22 μm filter (to reduce solid residue), place it in a polystyrene petri dish, and let it stand at room temperature for 36 hours. The solution becomes supersaturated, and orange transparent crystals precipitate, i.e., Rb₂Si. 0.7 Mn 0.3 F6 single crystal material.

[0065] Figure 1 The Rb2Si involved in Example 5 0.7 Mn 0.3 The X-ray diffraction patterns of the F6 single crystal in the (111) and (001) directions show a preferred orientation, which matches the characteristics of the (111) and (001) directions in the standard card, respectively, indicating that the single crystal was successfully synthesized. The single crystal sample involved in Example 5 was ground into powder, and its X-ray diffraction pattern matched the standard card pattern well. No diffraction peak signals of any impurity phase were observed, which indicates that the synthesized crystal sample is a pure phase.

[0066] Figure 2 The Rb2Si involved in Example 5 0.7 Mn 0.3 Schematic diagram of the refined structure of F6 single crystal. This sample is a cubic phase, Mn 4+ Ion partial substitution of Si 4+ Ion lattice position.

[0067] Figure 3 The Rb2Si involved in Example 5 0.7 Mn 0.3F6 single crystal micrographs and size distribution frequency diagrams show that the single crystal has a complete morphology, high transparency, and few surface defects. The sample size is concentrated in the range of 500-900 μm and the size is adjustable. Under natural light, it is an orange transparent crystal.

[0068] Figure 5 The figures show the photoluminescence excitation spectra of the fluorescent single-crystal materials involved in Examples 2, 5, and 7. As can be seen from the figures, with the increase of Mn content, the full width at half maximum (FWHM) of the excitation spectra are 51, 85, and 99 nm respectively, indicating an expansion of the effective excitation range of the material; typical Mn... 4+ The activating fluoride quenching concentration is low, around 5%, while the Mn content in the fluorescent single crystal involved in Example 5 is low. 4+ It can achieve a concentration of 30% without fluorescence quenching, thus having a wide excitation range. It can be excited not only by ultraviolet and blue light, but also by 410nm ultraviolet light, and can be applied to emerging ultraviolet LEDs or ultraviolet laser excitation devices.

[0069] Figure 6 The Rb2Si involved in Example 5 0.7 Mn 0.3 The quantum efficiency test results for F6 fluorescent single-crystal material are shown in the figure. As indicated, the sample exhibits narrow-spectrum red light emission under blue light excitation, with an internal quantum efficiency (IQE) approaching 100%, demonstrating the high efficiency of F6 fluorescent single-crystal Rb₂Si. 0.7 Mn 0.3 F6 in Mn 4+ No fluorescence quenching occurred even at a concentration as high as 30%, compared to typical Mn. 4+ With an activation quenching concentration of approximately 5% for fluorides, this series of fluorescent single crystals exhibits a breakthrough high quenching concentration; furthermore, high Mn... 4+ Concentration indicates a greater number of luminescent centers and higher absorption efficiency; therefore, the Rb2Si involved in Example 5... 0.7 Mn 0.3 F6 fluorescent single crystals have a breakthrough high external quantum efficiency (EQE) of 80.2%.

[0070] Example 6

[0071] Synthesis of A2Si 1-n Mn n F6 single crystal, composition A = Rb, n = 0.5, c(Mn) = 50%, i.e., Rb₂Si 0.5 Mn 0.5F6. Dissolve 2.0 mL of 30 wt% H₂SiF₆ solution, 1.045 g of RbF, and 1.699 g of Rb₂MnF₆ in 20 mL of 49 wt% HF solution with stirring, and add HF solution dropwise until saturated. Filter the reaction solution through a 0.22 μm filter (to reduce solid residue), place it in a polystyrene petri dish, and let it stand at room temperature for 36 hours. The solution becomes supersaturated, and orange transparent crystals precipitate, yielding Rb₂Si. 0.5 Mn 0.5 F6 single crystal material.

[0072] Example 7

[0073] Synthesis of A2Si 1-n Mn n F6, component A = Rb, n = 0.6, c(Mn) = 60%, i.e., Rb₂Si 0.4 Mn 0.6 F6 single crystals were obtained by dissolving 1.6 mL of 30 wt% H₂SiF₆ solution, 0.8356 g of RbF, and 2.039 g of Rb₂MnF₆ in 20 mL of 49 wt% HF solution with stirring, and then adding HF solution dropwise until saturation. The reaction solution was filtered through a 0.22 μm filter and placed in a polystyrene petri dish. After standing at room temperature for 36 hours, the solution became supersaturated, and orange transparent crystals, i.e., Rb₂Si, precipitated. 0.4 Mn 0.6 F6 single crystal material.

[0074] Example 8

[0075] Synthesis of A2Si 1-n Mn n F6 single crystal, composition A = Rb, n = 1.0, c(Mn) = 100%, i.e., Rb2MnF6. 3.399 g of Rb2MnF6 was dissolved in 20 mL of 49 wt% HF solution with stirring, and HF solution was added dropwise until saturation. The reaction solution was filtered through a 0.22 μm filter (to reduce solid residue), placed in a polystyrene petri dish, and allowed to stand at room temperature for 36 hours. The solution became supersaturated, and orange transparent crystals precipitated, yielding Rb2MnF6 single crystal material.

[0076] Figure 4 The calculated Helmholtz free energy values ​​for the single-crystal material components in Examples 1-8 show that, for any component (n = 0-1) and within the material synthesis and application temperature range (300K-400K), the Helmholtz free energy ΔF(n,T) ≤ 0, proving that the luminescent center Mn 4+ Continuous solid solution in material structures is a way to avoid phase separation and achieve high Mn content. 4+ The prerequisite for fluoride content.

[0077] Example 9

[0078] Synthesis of A2Si 1-n Mn n F6 single crystal, composition A2 = CsRb, n = 0.3, c(Mn) = 30%, i.e., CsRbSi 0.7 Mn 0.3 F6. Dissolve 2.8 mL of 30 wt% H₂SiF₆ solution, 1.519 g CsF, 0.4178 g RbF, and 1.020 g Rb₂MnF₆ in 20 mL of 49 wt% HF solution with stirring, and add HF solution dropwise until saturated. Filter the reaction solution through a 0.22 μm filter (to reduce solid residue), place it in a polystyrene petri dish, and let it stand at room temperature for 36 hours. The solution becomes supersaturated, and orange transparent crystals precipitate, i.e., CsRbSi. 0.7 Mn 0.3 F6 single crystal material.

[0079] Figure 7 This is a quantum efficiency test graph of the fluorescent single crystal involved in Example 9. As shown in the figure, the sample has an internal quantum efficiency (IQE) close to 100%, indicating that the fluorescent single crystal CsRbSi... 0.7 Mn 0.3 F6 in Mn 4+ No fluorescence quenching occurred even at a concentration as high as 30%, compared to typical Mn. 4+ With an activation quenching concentration of approximately 5% for fluorides, this series of fluorescent single crystals exhibits a breakthrough high quenching concentration; furthermore, high Mn... 4+ Concentration indicates a greater number of luminescent centers and higher absorption efficiency; therefore, the CsRbSi involved in Example 9... 0.7 Mn 0.3 F6 fluorescent single crystals have a high external quantum efficiency (EQE) of 78.8%.

[0080] Figure 8 The images show the photoluminescence spectra of the fluorescent single crystals involved in Examples 5 and 9. The fluorescent single crystals involved in Examples 5 and 9, when excited by 460 nm blue light, emit high-purity, narrow-spectrum red light with a full width at half maximum (FWHM) of 3.0 nm. Specifically, the fluorescent single crystal involved in Example 9 exhibits a slight redshift in its emission peak after component modulation.

[0081] Figure 9 These are the chromaticity coordinates of the fluorescent single crystals involved in Examples 5 and 9. The points marked "NTSC R" and "Rec.2020R" are the red coordinates according to the NTSC and Rec.2020 standards, respectively, and the point marked "KSF" is the commercial phosphor K2SiF6:Mn. 4+Photoluminescence spectral chromaticity coordinates. Through component adjustment, the chromaticity coordinates of Example 9 reached (0.6991, 0.3008), and the chromaticity coordinates of Example 5 reached (0.6952, 0.3047). Compared with KSF (0.6942, 0.3057), the fluorescent single crystals involved in the examples are closer to the Rec.2020 standard red light, and have the prospect of wide color gamut display applications.

[0082] Example 10

[0083] Using violet laser as the light source, combined with Ce 3+ Activate Ca2LuHf2Al3O 12 Cyan fluorescent powder, commercial Ce 3+ Activation of green phosphor and Rb2Si involved in Example 5 0.7 Mn 0.3 The F6 red fluorescent single-crystal packaged laser lighting device activates a violet laser source, emitting bright warm white light.

[0084] Figure 10 This is the spectrum of the laser illumination device involved in Example 10. Due to Rb2Si 0.7 Mn 0.3 F6 red fluorescent single crystal has an ultra-wide absorption range and can be effectively excited by violet light. Therefore, its application can be extended to the violet light-excited lighting device involved in Example 10, which supplements the red light component of the laser lighting device. The device emits warm white light with a color temperature of 4121K and has a high color rendering index of Ra=91.0.

[0085] Example 11

[0086] Using 460nm blue LEDs as the light source, β-SiAlON:Eu 2+ Green phosphor, as the green light component, is CsRbSi involved in Example 9. 0.7 Mn 0.3 F6 red fluorescent single crystals are used as the red light component to encapsulate white LED backlight devices for displays. When connected to a blue LED light source, the device emits bright, cool white light.

[0087] Figure 11 The image shows the spectrum of the white LED backlight device described in Example 11. The chromaticity coordinates of Example 9 are (0.6991, 0.3008), which are closer to the Rec.2020 standard red light than those of KSF and the fluorescent single crystal described in Example 5. Therefore, the white LED backlight device described in Example 11 emits 6980K cool white light and has a 106% NTSC wide color gamut. Furthermore, the CsRbSi backlight device described in Example 9... 0.7 Mn 0.3F6 red fluorescent single crystal has high external quantum efficiency, which helps to improve the luminous efficiency of the device, achieving a high luminous efficiency of 125.2 lm / W.

[0088] Comparative Examples 1-4

[0089] Synthesis of K2Si 1-n Mn n F6 single crystals, composition n = 0.10\0.25\0.5\0.75. 2.0 mL of 30 wt% H₂SiF₆ solution, 0.2905 g of KF, and 0.1236 / 0.3954 / 1.236 / 3.707 g of K₂MnF₆ were dissolved in 10 mL of 49 wt% HF solution with stirring. HF solution was added dropwise until saturation. The reaction solution was filtered through a 0.22 μm filter and placed in a polystyrene petri dish. After standing at room temperature for 36 hours, the solution became supersaturated, and orange transparent crystals precipitated.

[0090] Figure 12 These are micrographs of the crystals synthesized in Examples 1 and 4-8, showing Rb₂Si. 1-n Mn n F6 single crystals are all cubic phase.

[0091] Figure 13 These are micrographs of the synthesized crystals in Comparative Examples 1-4 under blue light irradiation, showing K2Si. 1-n Mn n During the synthesis of F6, when n is greater than 0.10, the product cannot form a cubic pure phase target product; instead, it separates into partial hexagonal phase crystals. This phenomenon is attributed to the fact that K2MnF6 synthesized at room temperature and pressure is hexagonal, while K2Si... 1-n Mn n F6 is difficult to achieve continuous solid solution in the same phase: when the Mn concentration increases to c(Mn) > 10%, Mn tends to enrich in the hexagonal phase, resulting in phase separation. This will lead to Mn in the cubic single crystal being lower than the theoretical value, making it impossible to synthesize high-Mn-concentration cubic single crystals. In addition, hexagonal crystals strongly absorb blue light and emit almost no light, acting as quenching centers and affecting the luminescence efficiency of the product.

[0092] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A high Mn 4+ Fluorosilicate fluorescent single crystal materials with a high content of fluorine silicates are characterized by, The chemical formula is A2Si 1-n Mn n F6; where A is one or a combination of two alkali metals Rb and Cs; n is Mn 4+ Ions relative to Mn 4+ and Si 4+ The molar ratio of the total amount of ions, 0 < n ≤ 1.

2. The high Mn content according to claim 1 4+ Fluorosilicate fluorescent single crystal materials with a high content of fluorine silicates are characterized by, The range of n is 0.02 ≤ n ≤ 0.60; The high Mn 4+ Fluorosilicate fluorescent single crystals are cubic phase with a single crystal size of 10–900 μm.

3. The high Mn content according to claim 1 4+ Fluorosilicate fluorescent single crystal materials with a high content of fluorine silicates are characterized by, The high Mn 4+ Fluorosilicate fluorescent single crystal materials exhibit multi-peak sharp-line narrow-spectrum red light emission at ~630 nm under ultraviolet, violet, or blue light excitation.

4. The high Mn content according to claim 1 4+ Fluorosilicate fluorescent single crystal materials with a high content of fluorine silicates are characterized by, At 300K-400K, the high Mn 4+ The Helmholtz free energy ΔF(n,T) of fluorosilicate fluorescent single crystal materials is ≤0.

5. A high Mn content according to any one of claims 1 to 4 4+ A method for preparing fluorosilicate fluorescent single crystal materials, characterized in that, The preparation method is a component-controlled single crystal method, which includes the following steps: S1. Preparation of Mn-containing precursors via ion exchange reaction; S2. Under stirring conditions, dissolve the silicon component raw material, alkali metal raw material, and Mn-containing precursor in hydrofluoric acid solution. Add hydrofluoric acid solution until saturated to obtain a reaction solution. Filter the reaction solution, let it stand, and crystals precipitate out as the solution becomes supersaturated; these are high-Mn crystals. 4+ Fluorosilicate fluorescent single crystal materials.

6. The high Mn content according to claim 5 4+ A method for preparing fluorosilicate fluorescent single crystal materials, characterized in that, The specific steps of S1 are as follows: dissolve excess RbF and / or CsF in hydrofluoric acid solution, add K2MnF6 to carry out ion exchange reaction, and then wash and dry to obtain Mn-containing precursor; The Mn-containing precursor is either cubic Cs2MnF6 or cubic Rb2MnF6.

7. The high Mn content according to claim 5 4+ A method for preparing fluorosilicate fluorescent single crystal materials, characterized in that, The silicon component raw material mentioned in S2 is selected from one or more of H2SiF6 solution, K2SiF6 or SiO2; The alkali metal raw material is selected from one or a combination of two of RbF, RbCl, Rb2CO3 or CsF; The filtration described in S2 is through a 0.22μm filter, and the settling temperature is room temperature.

8. The high Mn content according to claim 7 4+ A method for preparing fluorosilicate fluorescent single crystal materials, characterized in that, The ratio of the molar content of manganese in the Mn-containing precursor to the sum of the molar content of manganese in the Mn-containing precursor and the molar content of silicon in the silicon component raw material is 0 to 1. The concentration of the H2SiF6 solution is 20–40 wt%; the concentration of the hydrofluoric acid solution is 40–60 wt%.

9. The high Mn content according to any one of claims 1 to 4 4+ Application of high-content fluorosilicate fluorescent single crystal materials in LED devices.

10. A wide color gamut device, characterized in that, The wide color gamut device is the high Mn as described in any one of claims 1 to 4. 4 + Fluorosilicate fluorescent single crystal materials, light-emitting diodes, and phosphors are encapsulated into white LED devices; The light-emitting diode is an ultraviolet, near-ultraviolet, violet, or blue light-emitting diode; the phosphor is β-SiAlON:Eu 2+ Green fluorescent powder.

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