Fluoride fluorescent powder as well as preparation method and application thereof

Abstract

The invention discloses fluoride fluorescent powder and a preparation method and application thereof, the fluoride fluorescent powder contains an inorganic compound, the inorganic compound has the same crystal structure as cubic phase K2GeF6, the space group of the inorganic compound is # imgabs0, the chemical general formula of the inorganic compound is AaDbEcMx, 1.5 < = a < = 2.5, 0.8 < = b < = 1.2, 5.5 < = c < = 6.5, and 0.001 < = x < = 0.3. The luminescent material of the fluoride fluorescent powder provided by the invention has excellent luminous efficiency, thermal stability and color expression, and is suitable for the fields of high-performance display, illumination and energy conversion.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of luminescent materials, and in particular to a fluoride phosphor and a preparation method and application thereof. Background Art

[0002] With the rapid development of modern display technology and lighting equipment, the demand for luminescent materials continues to grow, especially in terms of improving display effects, luminous efficiency, and color rendering. Research on luminescent materials has become a key technology for enhancing display device performance. In particular, improving the luminous efficiency, color gamut, and lifespan of light sources in display technologies such as liquid crystal displays (LCDs), organic light-emitting diodes (OLEDs), and quantum dot light-emitting diodes (QLEDs) has become a core goal of technological development. In these areas, the performance of luminescent materials not only determines the fineness of the display but also directly impacts the device's energy efficiency, environmental adaptability, and manufacturing cost. In LCD technology, the choice of backlight is crucial to the final display effect. The backlight must provide uniform and stable light output while meeting color gamut and brightness requirements. Due to the inherent structural characteristics of LCD display technology, it relies on an external backlight to provide the required light. This means that the backlight's performance directly affects the brightness, contrast, and color reproduction of the LCD display. In the high-end LCD market, users are particularly demanding a higher color gamut, requiring backlights with a wider color gamut coverage. To meet this demand, traditional cold cathode fluorescent lamps (CCFLs) are gradually being replaced by more efficient and longer-lasting LED light sources. White LEDs that combine blue LED chips with phosphors have become the current mainstream solution. This configuration not only offers a longer lifespan, lower light decay, and lower manufacturing costs, but also provides more stable light color characteristics, thus replacing traditional backlight technology and driving a technological leap forward in the display field.

[0003] However, despite the increasing advantages of LEDs as backlight sources for liquid crystal displays, the issue of color gamut expansion remains a major bottleneck limiting further improvements in display quality. Especially in high-end display technology, how to break through the performance bottleneck of existing phosphors, improve the color gamut range, and meet the needs of more color levels has become a major challenge facing liquid crystal display technology. In current fluorescent conversion white light LED technology, the ratio of red, green, and blue phosphors has a crucial impact on the color gamut range and color saturation. Red phosphor, as a key material affecting color gamut expansion and realism, its luminous efficiency, thermal stability, and the width of the luminescence spectrum band all directly determine the color performance of the display device. Therefore, improving the performance of red phosphors, especially in terms of color purity and luminous efficiency, has become an important topic in the development of display technology.

[0004] Although some existing red phosphor materials, such as Mn4+ System red phosphors, etc., have broken through the performance bottleneck of traditional materials to a certain extent, but their luminous efficiency and stability still have a lot of room for improvement. The luminous efficiency of these traditional red phosphors gradually tends to saturation under certain conditions, especially in high-power or high-temperature environments, the performance of the phosphors is easily limited. In order to solve this problem, researchers have begun to focus on the research and development of new red phosphor systems, in order to break through the performance bottleneck of existing materials and meet the needs of high color gamut and high luminous efficiency in liquid crystal displays and other display technologies. The research and development of new red phosphor systems can not only enhance the realism of the display effect, but also improve the overall display performance, and provide more reliable material support for liquid crystal display technology and other display fields. In this context, the development of new red phosphor systems is particularly important. Studies have shown that red phosphor systems with certain activation centers have high color purity and luminous efficiency. In particular, Mn 4+ , which has high energy efficiency, narrow emission band and good thermal stability, has become the most competitive activator in red phosphors. 4+ The electronic configuration is 3d 3 , can effectively emit red light in a suitable crystal environment, and the emission wavelength is usually in the range of 600-650nm. 4+ The luminescence spectrum band is narrow and has high color purity, so it is widely used in liquid crystal displays and other display technologies.

[0005] However, despite the Mn 4+ Although it has many advantages, its luminous efficiency still faces room for improvement, especially under high temperature and high power density conditions, the luminous performance may be subject to certain limitations. 4+ Increasing the luminous efficiency of red phosphors and optimizing their energy level structure and doping environment in the crystal have become the key to improving the performance of red phosphors. In recent years, more and more research has focused on further improving the luminous efficiency and thermal stability of activated ion systems by optimizing the crystal structure and elemental composition of the materials.

[0006] According to the symmetry of the crystal, natural substances can be divided into seven crystal systems. Among these seven crystal systems, the cubic system has high symmetry and good structural stability, which can effectively reduce lattice defects and improve the thermal and chemical stability of phosphors. Secondly, the cubic system usually has a wide band gap, which is conducive to doping active ions (such as Eu 3+ 、Mn 4+ The cubic crystal system is an ideal matrix for red phosphors. However, many cubic phase materials are usually high-temperature stable phases (such as K2GeF6), and the activator Mn in high temperature environments is not suitable for red phosphors. 4+The difficulty in maintaining stability leads to poor luminescence performance of the corresponding red phosphor, which cannot meet market demand. Therefore, selecting the right preparation process to obtain cubic red phosphor is the key to further improving the luminous efficiency of red phosphor.

[0007] In summary, the advancement of LCD display technology, characterized by high resolution, thinness, and high color saturation, has placed higher demands on the performance of luminescent materials, particularly red phosphors, which play a crucial role in LCD technology. With the continuous advancement of display technology, overcoming the performance bottlenecks of existing phosphors, particularly in terms of luminous efficiency, color purity, and thermal stability, has become a core area of ​​technological innovation. The development of new, high-efficiency, narrow-bandwidth luminescent materials has become a key technology for improving display quality and meeting market demand. These materials will provide a solid foundation for the development of LCDs, LED backlights, and other display technologies. Summary of the Invention

[0008] (1) Purpose of the invention

[0009] The present invention aims to provide a fluoride phosphor, its preparation method, and its application. By optimizing the types and stoichiometric ratios of the elements in the inorganic compound, a more stable localized luminescence environment can be created, significantly enhancing luminous efficacy, emission intensity, and external quantum efficiency. The inorganic compound provided by the present invention can efficiently emit red light with a peak wavelength in the 600-650nm range under light excitation in the 400-470nm band. This red light has high emission intensity and a narrow half-width at half maximum, ensuring the purity and brightness of the luminescence.

[0010] (2) Technical solution

[0011] In order to solve the above problems, the first aspect of the present invention provides a fluoride phosphor comprising an inorganic compound having the same crystal structure as cubic phase K2GeF6 and a space group of The general chemical formula of the inorganic compound is A a D b E c M x Cubic phase K2GeF6 is a luminescent material with a special crystal structure, in which the Ge element is in a tetrahedral crystal field and the F element acts as a coordinating anion to interact with the metal ion. The crystal structure of the luminescent material in the present invention is cubic phase K2GeF6, and its space group is This structure has strong symmetry and can effectively improve the stability of the crystal. In this structure, Ge ions are in a tetrahedral structure, and F ions form a stable coordination environment with Ge ions as ligands. Mn ions can be embedded in this crystal structure and interact with Ge ions through an energy transfer mechanism to improve luminescence efficiency. The Mn-doped luminescent material can improve its luminescence performance through an energy transfer mechanism under the action of an excitation light source, and has excellent luminescence efficiency and external quantum efficiency. The luminescent material in the present invention further optimizes the crystal structure and improves the luminescence performance by rationally selecting and matching component A, component D, and component E. In the chemical formula of the inorganic compound, 1.5≤a≤2.5, 0.8≤b≤1.2, 5.5≤c≤6.5, and 0.001≤x≤0.3. By rationally selecting the content of these elements, the performance of the luminescent material can be optimized and the light efficiency and stability of the material can be improved. Preferably, 1.8≤a≤2.2, 5.8≤c≤6.2. This ratio helps improve the luminous efficiency of the material while ensuring stability, allowing the final luminescent material to achieve higher light conversion efficiency in practical applications. The different ratios of components A, D, and E will directly affect the stability of the crystal structure and the luminescent performance. Further narrowing the stoichiometric ratio range of components A, D, and E to 1.8≤a≤2.2 and 5.8≤c≤6.2 can achieve a more stable crystal structure and further improve luminescent performance.

[0012] Furthermore, the A component includes Li, Na, K, Rb, Cs, At least one of Mg, Ca, Sr and Ba elements or ionic groups, the chemical properties of which belong to I A or II A Group elements have high chemical activity and can be used as matrix ions in luminescent materials. Although it is an amino group ion, its chemical properties are similar to those of other A group elements, so it can also be used to replace conventional A components. In practical applications, the type and proportion of A components will be optimized according to the required luminescence properties, which can adjust the crystal field and crystal structure of the material, thereby affecting the luminescence performance. Preferably, the A component includes Li, Na, K, Rb, Cs, At least one or two of Mg, Ca, Sr, and Ba, and at least K, the molar percentage of K in A is 50% to 100%. This design can effectively increase the influence of K element on the material and further optimize its luminescence performance. K, Na, Li and other ions in the elements can be replaced as matrix ions, and the proportion of K ions can be adjusted between 50% and 100%. K ions have high chemical stability and can ensure the stability of the luminescent material during long-term operation. In some embodiments, component A can include a combination of elements such as K, Na, and Li. These elements can replace each other to adjust the performance of the material without changing the crystal structure.

[0013] Furthermore, the D component includes at least one of Ti, Zr, Hf, Si, Ge and Sn; the E component is at least one of F, Cl, Br, I and O. Ge in the D component is one of the key elements of the present invention, which is located in IV B Group elements have stable chemical properties and strong substitution ability with other elements. Ge element not only has a large ionic radius, but also has a good coordination relationship with the Mn ion in the luminescent center, which can better provide a stable luminescent environment. In order to maintain the stability of the crystal structure, the D component contains at least Ge element, and other IV elements such as Ti, Zr, Hf, etc. can be selected according to needs. B Group or IV A Preferably, the D component contains at least Ge, and other IV elements such as Ti, Zr, Hf, etc. can be selected according to needs. B Group or IV A Group elements. The molar percentage of Ge in the D is 50% to 100%, thereby ensuring the positive regulation of the Ge element on the stability of the crystal structure of the material and the luminescence characteristics. The appropriate addition of Ge elements not only enhances the stability of the crystal structure of the material, but also optimizes the spectral characteristics and improves the luminous efficiency of the material. The substitution of Ge, Ti, Zr and other ions in the D component in the crystal structure can also affect the luminescence performance. As a key component in the D component, Ge ions have a good coordination relationship with the Mn ions in the luminescence center and can effectively improve the luminescence efficiency. In order to ensure the stability of the crystal structure, the proportion of Ge in the D component is usually between 50% and 100%.

[0014] The M component includes one or both of Mn and Eu, with at least Mn being present. These are common luminescent doping elements. In the present invention, the M component includes at least Mn, and its doping can effectively improve the luminous efficiency of the material. After Mn doping, the excitation spectrum of the material is typically in the ultraviolet or visible light range, effectively absorbing blue light excitation and converting it into emitted light, thereby improving the luminous intensity and external quantum efficiency of the material.

[0015] Furthermore, the E component is one or two of the elements F, Cl, Br, I, and O, and at least contains F, and the molar percentage of F in the E is greater than 50%. The F element plays an important role in the luminescent material. It helps to improve the luminous efficiency of the luminescent material and ensures the efficient energy absorption of the luminescent material within the excitation wavelength range. Anions such as F, Cl, Br, I, and O can affect the crystal field environment of the luminescent material and regulate the luminescent properties of the luminescent center. In particular, the F element, due to its strong electronegativity, can stabilize the position of the luminescent center and improve the stability of the crystal. As the main component of the E component, the F element has a strong electronegativity that enables it to form strong bonds with metal ions and stabilize the crystal field environment of the luminescent center. The coordination of F ions can effectively suppress the generation of lattice defects and reduce the existence of non-radiative transition paths, thereby improving the luminous intensity and external quantum efficiency of the luminescent material. The proportion of F in the E component is usually greater than 50% to ensure that the luminescent center is fully stabilized. Anions such as F, Cl, Br, I, and O in the E component modulate the properties of the crystal field through differences in electronegativity. F, with its highest electronegativity, effectively stabilizes the crystal environment of the luminescent center. F coordination not only enhances luminescence intensity but also reduces lattice defects, ensuring the long-term stability of the luminescent material.

[0016] Furthermore, the A component is K and the D component is Ge. This combination can further improve the luminescence efficiency of the material, ensuring that the material can efficiently absorb energy during the light excitation process and convert it into high-intensity light emission. When the A component is K, its molar ratio can be adjusted between 50% and 100%. K as the A component has high chemical stability and can maintain the stability of the luminescent material within a higher temperature range, thereby ensuring that the luminescent material can still maintain excellent luminescence performance in a high temperature environment. When the proportion of Ge in the D component is 50% to 100%, it can ensure that the Ge ions occupy key positions in the crystal structure, thereby optimizing the performance of the luminescent center and further improving the luminescence intensity and stability of the material.

[0017] A second aspect of the present invention provides a method for preparing the fluoride phosphor described in any one of the above descriptions, comprising:

[0018] According to the chemical formula A a D b E c M x The stoichiometric ratios of each element were weighed and mixed as follows:

[0019] S1. A D-containing compound, a portion of an A-containing compound, and an M-containing compound are mixed and dissolved in a predetermined mass concentration of HF aqueous solution. During the mixing reaction, the pH of the entire solution is controlled below 2.0 to prepare a first solution. The D-containing compound comprises at least one of a D-containing fluoride and oxide, and the M-containing compound comprises at least one of a fluoromanganate, a manganese oxide, and a europium-containing compound. The mass concentration of the HF aqueous solution should be controlled between 35% and 45% to ensure sufficient dissolution of the fluoride and avoid excessive concentrations that may cause unwanted side reactions. The mass concentration of the D compound solution is 10-15%. The pH of the solution should be adjusted to below 2.0, which makes the solution acidic, helping to control the solubility of the fluoride, preventing excessive dissolution and promoting subsequent crystal precipitation. The mass concentration of the fluoride solution should be maintained between 10-15%. The temperature during the dissolution process should be maintained between 25-35°C, which is conducive to fluoride dissolution and crystal growth and avoids the formation of excessive byproducts caused by high temperatures.

[0020] S2, dissolving the remaining portion containing compound A in an organic solvent, mixing, heating and stirring to prepare a second solution, wherein the mass concentration percentage of compound A in the second solution is 10% to 15%. The organic solution includes at least one of triethanolamine, glycine, taurine, glycerol and sorbitol. The mixing, heating and stirring time is 50 to 150 minutes. Insufficient stirring time will result in the first solution and the second solution not being able to mix evenly. Too long stirring time will easily lead to excessively large particle size, which cannot meet application requirements. The mass concentration percentage of the organic solvent solution should be between 10% and 15%. If the corresponding mass concentration percentage of compound A is too low, the phosphor crystals will grow slowly. If the solution concentration is too high, the phosphor crystals will obviously agglomerate, thereby affecting the application effect.

[0021] S3, add the second solution dropwise to the first solution and heat it, filter the reactants to obtain a precipitate; the second solution is added at a rate of 2 to 8 ml / min. The recommended dropwise addition rate for the second solution is 2 to 8 ml / min. Too fast a dropwise addition may cause uneven crystal growth, while too slow a dropwise addition may increase the reaction time and affect production efficiency. When the second solution is added dropwise to the first solution, maintain the reaction temperature at 40 to 55°C. This temperature can effectively promote the crystallization and crystal growth of the fluoride, while avoiding changes in the Mn valence state due to excessively high temperature, which affects the luminescence performance.

[0022] S4, washing the precipitate with a 2% to 5% HF aqueous solution and then ethanol, and drying to obtain a fluoride phosphor. Add a 2% to 5% HF aqueous solution to the precipitate, stirring and washing it three times to ensure the removal of unreacted impurities. Next, wash it twice with an ethanol solution to further remove organic impurities. The washed precipitate is air-dried at a drying temperature of 55 to 85°C to obtain the corresponding fluoride phosphor. During the drying process, maintain appropriate wind speed and temperature to ensure the structural integrity of the crystals and the quality of the final product.

[0023] A third aspect of the present invention provides a light-emitting device comprising a housing, an excitation light source, and a fluoride phosphor (luminescent material). The excitation light source is fixedly connected to the fluoride phosphor and encapsulated within the housing. The fluoride phosphor comprises any of the fluoride phosphors described above or a fluoride phosphor prepared by any of the methods described above. This light-emitting device can efficiently excite the luminescent material through the excitation light source and utilize its excellent luminescent properties to achieve efficient light energy conversion.

[0024] The excitation light source is a semiconductor chip with a peak emission wavelength range of 400-470nm. This effectively excites the Mn ions in the luminescent material and enhances the luminescence intensity of the luminescent material through an energy transfer mechanism. This excitation wavelength range matches the absorption band of the luminescent material, maximizing the energy of the excitation light source, minimizing energy loss, and improving overall light conversion efficiency. Such light-emitting devices are widely used in lighting, display, laser, and other fields, and have broad market prospects.

[0025] (3) Beneficial effects

[0026] The above technical solution of the present invention has the following beneficial technical effects: The present invention provides a fluoride phosphor and its preparation method and application, which aims to significantly improve the luminous efficiency, thermal stability, color expression and brightness of the luminescent material through precise element design and reasonable component ratio, thereby meeting the stringent requirements of modern display, lighting and energy conversion and other high-performance application fields for luminescent materials. The luminescent material is based on an inorganic compound and is composed of component A (such as K), component D (such as Ge), component E (F) and component M (such as Mn). The general chemical formula of the inorganic compound is A a D b E c M x , where 1.5≤a≤2.5, 0.8≤b≤1.2, 5.5≤c≤6.5, 0.001≤x≤0.3. In this compound, component A includes Li, Na, K, Rb, Cs, At least one of Mg, Ca, Sr and Ba elements or ionic groups, the chemical properties of which belong to IA or II A Group elements have high chemical activity and can be used as matrix ions in luminescent materials. Although it is an amino group ion, its chemical properties are similar to those of other A-type elements, so it can also be used to replace the conventional A component. Among the alternative compositions of the A component, the K element has a high chemical stability, which can ensure the stability of the luminescent material during long-term operation, thereby ensuring that the luminescent material can still maintain excellent luminescence performance in a high-temperature environment. The D component includes at least one of the elements Ti, Zr, Hf, Si, Ge and Sn, and forms an octahedral structure [DE6] with the E component in the crystal structure, thereby providing a suitable doping site for the luminescent center M component. Among the alternative elements of the D component, Ge is one of the key elements of the present invention, which is located in IV B The ionic radius of Ge is close to that of Mn (Mn 4+ The ionic radius is Ge 4+ The ionic radius is ), and has a good coordination relationship with the Mn ions of the luminescent center, which can better provide a stable luminescent environment. The E component is at least one of F, Cl, Br, I and O elements. The anions such as F, Cl, Br, I, O in the E component adjust the properties of the crystal field through the difference in electronegativity. The F element has the highest electronegativity (3.98) and can effectively stabilize the crystal environment of the luminescent center. The coordination of F can not only improve the luminous intensity, but also reduce lattice defects and ensure the long-term stability of the luminescent material. Therefore, the high proportion of the F element in the E component helps to enhance the energy absorption efficiency of the material, thereby increasing the excited state lifetime of the material and ultimately improving the light conversion efficiency. The compound has a cubic crystal structure, and the space group is The choice of this structure not only provides higher symmetry, but also helps to improve the luminous efficiency and thermal stability of the material. Specifically, the luminescent material of the present invention can efficiently produce red light (600-650nm) under the excitation of a blue light LED (400-470nm), with a high emission intensity and a narrow half-width, ensuring the purity and high saturation of the luminescent color. Through precise control of the type and content of elements, the material has been significantly improved in luminous efficiency, avoiding the energy loss caused by the formation of defect states. In addition, the material also shows excellent performance in color expression and brightness, and can meet the needs of fields such as ultra-high color gamut display, intelligent lighting, and efficient energy conversion. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is the space group Schematic diagram of the spatial structure and molecular diagram of similar materials;

[0028] Figure 2 is the XRD pattern of the luminescent material prepared in Example 1 of the present invention;

[0029] Figure 3 is partial electron diffraction data of the luminescent material prepared in Example 1 of the present invention;

[0030] Figure 4 is a schematic diagram of the crystal structure obtained by analyzing the luminescent material prepared in Example 1 of the present invention;

[0031] Figure 5 1 is an excitation and emission spectrum diagram of an experimental sample of the luminescent material prepared in Example 1 of the present invention; Figure 5 (a) is the 631nm excitation spectrum of the luminescent material sample prepared in Example 1, Figure 5 (b) is the emission spectrum of the sample prepared in Example 1 at 460 nm excitation. DETAILED DESCRIPTION

[0032] To make the objectives, technical solutions, and advantages of the present invention more clearly understood, the present invention will be further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings. It should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present invention.

[0033] Comparative Example 1

[0034] This comparative example provides rhombohedral K2Ge 0.98 F6Mn 0.02 ( ) compound, and its luminous intensity under 460nm blue light excitation is set to 100. The preparation method is as follows: This embodiment provides a K2Ge 0.98 F6Mn 0.02 The preparation method of the phosphor is as follows: weigh 2.92g potassium fluoride (KF), 0.03g manganese fluoride (MnF2) and 2.14g germanium dioxide (GeO2), and mix the above raw materials evenly according to the chemical structure and stoichiometric ratio; dissolve the mixed raw materials in 10mL of hydrofluoric acid (HF) aqueous solution with a mass concentration of 40%, and stir until completely dissolved to prepare a first solution. During the dissolution process, the solution temperature is maintained at room temperature (about 25°C) to ensure the full dissolution of the fluoride and promote subsequent crystal precipitation. Subsequently, the solution is allowed to stand at room temperature for 12 hours to allow K2Ge 0.98 F6Mn 0.02Crystals gradually precipitated. After the reaction was completed, the precipitate was collected by filtration and washed three times with a small amount of cold water to remove impurities and ensure that unreacted fluoride and by-products were fully removed. Finally, the washed precipitate was placed in an oven and dried at 60°C for 6 hours to ensure that residual solvent and moisture were completely removed while maintaining the integrity of the crystal structure to obtain the target product K2Ge 0.98 F6Mn 0.02 .

[0035] Comparative Example 2

[0036] This comparative example provides hexagonal K2Ge 0.5 Si 0.48 F6Mn 0.02 (P63mc) compound, the compound is synthesized by Si element induction under precipitation crystallization environment, the specific method is: the luminous intensity under 460nm blue light excitation is 97. This embodiment provides a K2Ge 0.5 Si 0.48 F6Mn 0.02 The preparation method of the phosphor is as follows: weigh 2.92g potassium fluoride (KF), 1.07g germanium dioxide (GeO2), 0.29g silicon dioxide (SiO2) and 0.03g manganese fluoride (MnF2), and mix the above raw materials evenly according to the stoichiometric ratio; dissolve the mixed raw materials in 10mL of hydrofluoric acid (HF) aqueous solution with a mass concentration of 40%, and stir until completely dissolved to prepare a first solution. During the dissolution process, the solution temperature is maintained at room temperature (25°C) to ensure that GeO2 and SiO2 fully react to generate H2GeF6 and H2SiF6, while avoiding high temperature-induced side reactions. Subsequently, the solution is allowed to stand at room temperature for 12 hours to allow K2Ge 0.5 Si 0.48 F6Mn 0.02 Crystals gradually precipitated. After the reaction was completed, the precipitate was collected by filtration and washed three times with a small amount of deionized water and 3% dilute HF solution to remove unreacted fluoride and by-products. Finally, the washed precipitate was placed in a vacuum drying oven and dried at 60°C for 6 hours, followed by annealing at 200°C in an inert gas (Ar) atmosphere for 2 hours to eliminate internal stress and optimize the crystal structure to obtain the target product K2Ge 0.5 Si 0.48 F6Mn 0.02 .

[0037] Example 1

[0038] This embodiment provides a K2Ge 0.95 F6Mn 0.05The phosphor is prepared as follows: weigh 116.2g of potassium fluoride (KF), 4.35g of manganese fluoride (MnF2) and 141.21g of germanium oxide (GeO2), and mix the above raw materials evenly according to the chemical structure and stoichiometric ratio; dissolve the mixed raw materials in 300g of hydrofluoric acid (HF) aqueous solution with a mass concentration of 40%, and stir thoroughly until completely dissolved to obtain a first solution. The pH value of the solution is adjusted to below 2.0 to ensure the full dissolution of the fluoride and promote subsequent crystal precipitation. During the dissolution process, the solution temperature is maintained at 35°C, which is conducive to the dissolution of the fluoride and crystal growth, and avoids the generation of excessive side reactions caused by high temperature. At the same time, weigh 50.00g of potassium fluoride (KF) and dissolve it in 190g of triethanolamine aqueous solution to obtain a second solution. Preferably, the mass concentration percentage of potassium fluoride in the second solution is controlled at 12% to ensure that cubic phase K2Ge can be stably generated under this environment. 0.95 F6Mn 0.05 Phosphor, while avoiding excessive concentration that affects the nucleation and growth of the crystal. Subsequently, the second solution is slowly injected into the first solution at a rate of 5 mL / min, and mechanically stirred at 55 ° C for 1.8 hours to ensure that the reaction is fully carried out. The injection rate is controlled between 2 and 8 mL / min to avoid uneven crystal growth or excessive reaction time resulting in excessive particle size. During the reaction, the stirring temperature is maintained at 40 to 55 ° C, which effectively promotes the crystallization and crystal growth of fluoride, while preventing changes in the valence state of Mn from affecting the luminescence performance. After the reaction is completed, the supernatant is removed by centrifugation or filtration, and the precipitate is retained; the precipitate is washed 3 times with 3.0% (mass concentration percentage) HF aqueous solution to remove impurities and ensure that unreacted fluoride and by-products are fully removed. Subsequently, it is washed twice with ethanol solution to further remove organic impurities and water-soluble impurities. Finally, the washed precipitate was placed in an oven and dried under 75°C with forced air. The drying time was controlled within 6 hours to ensure that the residual solvent and moisture were completely removed while maintaining the integrity of the crystal structure, thereby obtaining a bulk fluoride phosphor K2Ge. 0.95 F6Mn 0.05 Through the above steps, high-purity and structurally stable K2Ge can be prepared. 0.95 F6Mn 0.05 Phosphor is suitable for various optoelectronic applications, such as LED lighting, display devices and lasers. XRD test was performed on the sample of the embodiment, and its XRD diffraction data is as follows Figure 2 As shown, the phase was searched in Jade software, and the results showed that there was no substance in the software database that perfectly matched it. In order to further analyze its spatial structure, the structure of the example sample was analyzed by single crystal XRD test, and some crystal diffraction spots were as follows Figure 3According to the test results of single crystal XRD, the crystal structure of this embodiment was constructed by Vesta visualization software. The results are shown in Figure 4 As shown, the structure is consistent with the standard The crystal structure is similar ( Figure 1 ). Therefore, it can be confirmed that the crystal structure of its main phase is K2GeF6, and the space group is The luminescence properties of the material were analyzed by fluorescence spectrometer. The results showed that the material has a narrow spectrum of red luminescence under 460nm blue light excitation, with a peak wavelength of 630nm and a relative luminescence intensity of 117.1. Figure 5 The excitation and emission spectra of the luminescent material sample prepared in this embodiment are shown in FIG. Figure 5 (a) is the excitation spectrum of the luminescent material sample prepared in this embodiment at a monitoring wavelength of 631 nm, Figure 5 (b) is the emission spectrum of the luminescent material sample prepared in this embodiment at 460nm excitation. Figure 3 It can be seen that the luminescent material has high absorption intensity in the blue light region, and the emission spectrum ranges from 600 to 650 nm, showing excellent red luminescence performance.

[0039] Example 2

[0040] This embodiment provides a K2Ge 0.90 F6Mn 0.10The phosphor is prepared as follows: weigh 116.20g of potassium fluoride (KF), 94.16g of germanium oxide (GeO2) and 8.70g of manganese fluoride (MnF2), and mix the above raw materials evenly according to the chemical structure and stoichiometric ratio; dissolve the mixed raw materials in 300g of hydrofluoric acid (HF) aqueous solution with a mass concentration of 40%, and stir thoroughly until completely dissolved to obtain a first solution. The pH value of the solution is adjusted to below 2.0 to ensure the full dissolution of the fluoride and promote subsequent crystal precipitation. The solution temperature is maintained at 25-35°C during the dissolution process. At the same time, weigh 30.00g of potassium fluoride (KF) and dissolve it in 190g of glycine aqueous solution to obtain a second solution. Preferably, the mass concentration of potassium fluoride in the second solution is 14% to ensure its effectiveness while avoiding excessive concentration that affects the nucleation and growth of crystals. Subsequently, the second solution was slowly injected into the first solution at a rate of 5 mL / min, and mechanically stirred at 50-55°C for 1.8 hours to ensure that the reaction was fully carried out. The injection rate was controlled between 2 and 8 mL / min to avoid uneven crystal growth or excessive reaction time resulting in excessive particle size. During the reaction, the stirring temperature was maintained at 40-55°C to effectively promote the crystallization and crystal growth of fluoride, while preventing the change of Mn valence state from affecting the luminescence performance. After the reaction, the supernatant was removed by centrifugation or filtration, and the precipitate was retained; the precipitate was washed 3 times with 3.5% hydrofluoric acid (HF) aqueous solution to remove impurities and ensure that unreacted fluoride and by-products were fully removed. Subsequently, it was washed twice with ethanol solution to further remove organic impurities and water-soluble impurities. Finally, the washed precipitate was placed in an oven and dried with air at 75°C. The drying time was controlled to 6 hours to ensure that the residual solvent and moisture were completely removed while maintaining the integrity of the crystal structure to obtain a bulk fluoride phosphor K2Ge. 0.90 F6Mn 0.10 Through the above steps, high-purity and structurally stable K2Ge can be prepared. 0.90 F6Mn 0.10 Phosphors are suitable for various optoelectronic applications, such as LED lighting, display devices and lasers.

[0041] Example 3

[0042] This embodiment provides a The phosphor is prepared as follows: 69.54g of ammonium chloride (NH4Cl), 22.20g of calcium chloride (CaCl2), 244.44g of zirconium chloride (ZrCl4) and 37.75g of manganese chloride (MnCl2) are weighed, and the above raw materials are uniformly mixed according to the chemical structure and stoichiometric ratio, and then dissolved in 300g of hydrofluoric acid (HF) aqueous solution with a mass concentration of 40%, and stirred until completely dissolved to prepare a first solution. The pH value of the solution is adjusted to below 2.0 to ensure the full dissolution of the chloride and promote subsequent crystal precipitation. The solution temperature is maintained at 25-35°C during the dissolution process. At the same time, 40.0g of ammonium chloride (NH4Cl) is weighed and dissolved in 190g of taurine solution. The mass concentration of ammonium chloride is controlled to 15% to ensure the effectiveness of taurine and to avoid excessive concentration affecting the nucleation and growth of crystals. Subsequently, the second solution was slowly injected into the first solution at a rate of 5 mL / min, and mechanically stirred at 50-55°C for 1.8 hours to ensure that the reaction was fully carried out. The injection rate was controlled between 2 and 8 mL / min to avoid uneven crystal growth or excessive reaction time resulting in excessive particle size. During the reaction, the stirring temperature was maintained at 40-55°C to effectively promote the crystallization and crystal growth of the chloride, while preventing the change in the valence state of Mn from affecting the luminescence performance. After the reaction, the supernatant was removed by centrifugation or filtration, and the precipitate was retained; the precipitate was washed 3 times with a 3.5% hydrofluoric acid (HF) aqueous solution to remove impurities and ensure that unreacted chloride and by-products were fully removed. Subsequently, it was washed twice with an ethanol solution to further remove organic impurities and water-soluble impurities. Finally, the washed precipitate was placed in an oven and dried with air at 75°C for 6 hours to ensure that the residual solvent and moisture were completely removed while maintaining the integrity of the crystal structure to obtain a block chloride phosphor. Through the above steps, high-purity and structurally stable Phosphors are suitable for various optoelectronic applications, such as LED lighting, display devices and lasers.

[0043] The preparation processes of Examples 4-33 were similar to those of Examples 1-3. The raw powders used and the resulting compounds are shown in Table 1. The compositions, emission peak wavelengths, and relative luminous intensities of Comparative Example 1, Comparative Example 2, and Examples 1-33 under 460 nm excitation are shown in Table 1.

[0044] Table 1 Chemical formula and luminescence properties of comparative examples and embodiments

[0045]

[0046]

[0047] As can be seen from Table 1, under the same preparation conditions, the fluoride phosphor (luminescent material) provided by the embodiment of the present invention has improved luminous intensity under blue light chip excitation compared with Comparative Examples 1 and 2, which can further improve the luminous efficiency of the narrow-emission red phosphor and meet the application needs in the field of backlight sources for ultra-high color gamut displays.

[0048] According to the data in Table 1, it can be seen that the emission peak wavelength of the luminescent materials with the composition of the present application in Examples 1-33 is 631nm. The examples are all subjected to microcrystal electron diffraction tests. The results show that their space groups are According to Examples 3-14, it can be seen that the position of component A can be partially or completely replaced by other "+1" or "+2" cations with similar chemical properties, including but not limited to Li + 、Na + , Rb + 、Cs + Mg 2+ , Ca 2+ 、Sr 2+ 、Ba 2+ Plasma, D component can be partially or completely replaced by other "+4" cations, including but not limited to Si 4+ 、Sn 4+ , Hf 4+ 、Zr 4+ Elements such as Cl, Br, I, and O can be partially or completely replaced by E components, and the space groups of the formed compounds are All of them are narrow-band red luminescent materials. By comparing Examples 14-21 with Examples 3-14, it can be seen that reducing the corresponding stoichiometric ratio range to satisfy 1.8≤a≤2.2, 5.8≤c≤6.2 can improve the luminescence intensity. According to Examples 22-25, it can be concluded that increasing the molar percentage of K element in A can improve the luminescence intensity of the corresponding embodiment. According to Examples 26-29, it can be concluded that increasing the molar percentage of Ge element in component D can improve the luminescence intensity of the corresponding embodiment. According to Examples 30-33, it can be concluded that increasing the molar percentage of F element in component E can improve the luminescence intensity of the corresponding embodiment.

[0049] It should be understood that the above-described specific embodiments of the present invention are merely illustrative or illustrative of the principles of the present invention and do not constitute limitations of the present invention. Therefore, any modifications, equivalent substitutions, improvements, etc. made without departing from the spirit and scope of the present invention should be included within the scope of protection of the present invention. In addition, the appended claims are intended to cover all variations and modifications that fall within the scope and metes and bounds of the appended claims, or equivalents thereof.

Claims

1. A fluoride phosphor, characterized in that: The fluoride phosphor contains an inorganic compound having the same crystal structure as cubic phase K2GeF6 and its space group is The general chemical formula of the inorganic compound is A a D b E c M x , wherein 1.5≤a≤2.5, 0.8≤b≤1.2, 5.5≤c≤6.5, 0.001≤x≤0.3, wherein the A component includes Li, Na, K, Rb, Cs, At least one of Mg, Ca, Sr and Ba; the D component includes at least one of Ti, Zr, Hf, Si, Ge and Sn elements; the E component is at least one of F, Cl, Br, I and O elements; the M component includes one or two of Mn and Eu elements, and at least contains Mn element.

2. The fluoride phosphor according to claim 1, characterized in that: In the general chemical formula, 1.8≤a≤2.2, 5.8≤c≤6.

2.

3. The fluoride phosphor according to claim 1 or 2, characterized in that: The E component is one or two of the elements F, Cl, Br, I and O, and contains at least F. The molar percentage of F in the E is greater than 50%.

4. The fluoride phosphor according to claim 1 or 2, characterized in that: The A component includes Li, Na, K, Rb, Cs, At least one or two of Mg, Ca, Sr and Ba, and at least K, wherein the molar percentage of K in the A is 50% to 100%.

5. The fluoride phosphor according to claim 1, characterized in that: The A component is K.

6. The fluoride phosphor according to claim 1 or 2, characterized in that: The D component contains at least Ge, and the molar percentage of Ge in the D component is 50% to 100%.

7. The fluoride phosphor according to claim 1, characterized in that: The D component is Ge.

8. A method for preparing the fluoride phosphor according to claims 1-7, characterized in that: include: According to the chemical formula A a D b E c M x The stoichiometric ratios of each element were weighed and mixed as follows: Mixing a D-containing compound, a portion of an A-containing compound, and an M-containing compound, dissolving the mixed raw materials in an HF aqueous solution having a preset mass concentration percentage, and controlling the pH value of the entire solution system to be below 2.0 during the mixing reaction to prepare a first solution; wherein the D-containing compound includes at least one of a D-containing fluoride and an oxide, and the M-containing compound includes at least one of a fluoromanganate, a manganese oxide, and a europium-containing compound; Dissolving the remaining portion containing compound A in an organic solvent to prepare a second solution, wherein the mass concentration of compound A is 10% to 15%; adding the second solution dropwise to the first solution and heating the mixture, filtering the reactant to obtain a precipitate; The precipitate is washed with an HF aqueous solution with a mass concentration of 2% to 5% and ethanol in sequence, and then dried to obtain fluoride phosphor powder.

9. A light-emitting device comprising a housing, an excitation light source and fluoride phosphor, characterized in that: The excitation light source is fixedly connected to the fluoride phosphor and encapsulated in the housing. The fluoride phosphor comprises the fluoride phosphor according to any one of claims 1 to 7. 10 . The light-emitting device according to claim 9 , wherein the excitation light source is a semiconductor chip having an emission peak wavelength in the range of 400-470 nm.

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