A red nitride fluorescent powder and a preparation method and application thereof

Abstract

The application provides a red nitride fluorescent powder and a preparation method and application thereof, and belongs to the technical field of rare earth luminescent materials. 1‑x Li x Al 5‑x Si x N7]:yEu 2+ , wherein 0.001<=x<=0.50 and 0.0005<=y<=0.20. The fluorescent powder is a nitride system, has strong light absorption at blue light 400-500nm, has an excitation peak peak value at about 460nm, can be effectively excited by blue light laser, can emit red fluorescent light under blue light excitation, has an emission peak peak value at 635-685nm which can be adjusted, has a half peak width of 75-90nm which can be adjusted, and has a very good contribution to high color gamut in display devices. The fluorescent powder has the advantages of strong luminous brightness, high luminous efficiency and stable physical and chemical properties when used in various laser display devices with blue high-power laser as an excitation source.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of rare earth luminescent materials, and particularly relates to a red nitride fluorescent powder and a preparation method and application thereof. BACKGROUND

[0002] The development and progress of display technology have changed people's life, and the medium of long-distance communication has developed from pure text and sound to vivid image. For display devices, high-efficiency light sources have been increasingly used in displays. The display devices need high-efficiency narrow-peak fluorescent powder, that is, the required fluorescent powder needs to have a narrow emission band with a full width at half maximum (FWHM), a specific peak position, high quantum efficiency and good thermal stability. The commercial liquid crystal display (LCD) backlight source is currently adopted by "blue InGaN chip + β-SiAlON:Eu 2+ (λ em = 540 nm; FWHM = 55 nm) green fluorescent powder + K2SiF6:Mn 4+ (λ emThe encapsulation scheme of red phosphor "630 nm, sharp peak" is the scheme with the largest color gamut area based on phosphor technology in the current commercial market. The color gamut is mainly determined by the color coordinates of the red, green and blue (RGB) light emitted by the light emitting diode (LED) light source. The traditional display technology adopts LCD, and the core technology is that the backlight source adopts LED. However, there are some problems in LED as a backlight source, such as large optical expansion, low brightness, insufficient color purity, etc., which greatly limits the use of display devices in the field of high brightness and wide color gamut display, such as cinema, projection equipment, etc. In recent years, the laser light source technology and the LED light source technology belong to the solid-state light source technology, and are considered by the academic and industrial circles as the most potential green light source in the 21st century because of the advantages of long service life, low energy consumption and environmental friendliness. Because the emission bandwidth of laser is short, which means high efficiency, small size and high light output per unit laser diode (LD) area, high brightness, the use of laser to excite fluorescent materials can realize high color gamut display. Although the combination of red, green and blue lasers can realize high-purity laser display, the current green laser equipment is not only expensive but also has a problem called "green defect", and the design of multi-emission system also increases the cost. Therefore, the scheme of using blue laser and multi-color phosphor material to realize display is more efficient and more valuable for research. For devices using phosphor, the quality of the phosphor is the key to determine the performance of the device. Laser display technology still mainly uses the phosphor of the traditional LED technology, but considering the brightness saturation phenomenon of the phosphor under high power density light source, the requirements of the phosphor for laser are different from those for LED.

[0003] For narrow peak red phosphor, the narrowest Eu 2+ Sr[LiAl3N4]:Eu 2+ The emission of the fluorescent powder activated by Eu 4+ The emission of the fluorescent powder activated by Eu 4+ The fluoride system is represented by K2SiF6:Mn 2+ The fluoride system is represented by K2SiF6:Mn 4+The activated narrow-peak red phosphor has serious light-induced saturation and heat-induced saturation problems, and the light saturation threshold and light efficiency are too low to meet the laser display application. Overall, the narrow-peak red luminescent materials developed at home and abroad generally have low light efficiency and poor reliability. Therefore, high-efficiency phosphor with high-efficiency narrow-peak emission has become the key of technical research and the focus of display market, and an effective construction method for developing high-efficiency narrow-peak phosphor for display is urgently needed to break through the bottleneck of lack of key materials. SUMMARY

[0004] The present application provides a red nitride phosphor and a preparation method and application thereof, the red nitride phosphor has excellent red light emission, and the emission can realize high color gamut, and is easy to synthesize.

[0005] In order to realize the above-mentioned application purpose, the present application provides the following technical scheme:

[0006] The present application provides a red nitride phosphor, the chemical composition is Sr2[Mg 1-x Li x Al 5-x Si x N7]:yEu 2+ , wherein 0.001≤x≤0.50, 0.0005≤y≤0.20.

[0007] Preferably, x=0.02-0.4, y=0.01-0.06.

[0008] The present application provides a preparation method of the red nitride phosphor according to the above technical scheme, comprising the following steps:

[0009] According to the required stoichiometric ratio, the nitrogen-containing Sr source, the nitrogen-containing Mg source, the nitrogen-containing Al source, the nitrogen-containing Si source, the Li source and the Eu source are mixed, ground, and the mixture is obtained;

[0010] After the mixture is sintered, the grinding and sieving are sequentially carried out, and the red nitride phosphor is obtained.

[0011] Preferably, the Li source is lithium nitride or lithium aluminum hydride, and the Eu source is europium fluoride, europium nitride or europium oxide.

[0012] Preferably, the sintering pressure is 0-1.0 MPa, and the sintering atmosphere is nitrogen or nitrogen-hydrogen mixed gas.

[0013] Preferably, according to the volume percentage, the nitrogen-hydrogen mixed gas is mixed by 90% nitrogen and 10% hydrogen.

[0014] Preferably, the sintering temperature is 1100-1600 DEG C, and the holding time is 2-20 h. Preferably, the sintering temperature is 1100-1600 DEG C, and the holding time is 2-20 h.

[0015] The application provides application of the red nitride fluorescent powder in a blue laser display device.

[0016] The application provides application of the red nitride fluorescent powder in a liquid crystal display device excited by blue light.

[0017] The application provides a red nitride fluorescent powder, which has a chemical composition of Sr2[Mg 1-x Li x Al 5-x Si x N7]:yEu 2+ , wherein 0.001≤x≤0.50 and 0.0005≤y≤0.20. In the Sr2[MgAl5N7]:Eu 2+ , Li and Si are simultaneously added to balance the electric charge, and meanwhile, the lattice is shrunk to enhance the lattice rigidity, so that the quantum efficiency and the luminescent thermal stability are improved. The fluorescent powder is a nitride system, has a strong light absorption at blue light of 400-500 nm, has an excitation peak at about 460 nm, can be effectively excited by blue light, can emit red fluorescent light under the excitation of blue light, has an emission peak at 635-685 nm and a half-peak width of 75-90 nm, and has a good contribution to a high color gamut in a display device. The fluorescent powder is used in various laser display devices with blue high-power laser as an excitation source, has the advantages of high luminous intensity, high luminescent efficiency and stable physical and chemical properties, and meets the performance requirements of high-performance devices. The results of the examples show that, compared with a sample SMAN:0.01Eu 2+ , the sample SMAN-0.1LS:0.01Eu 2+ , the external quantum efficiency is improved from 28.1% to 42.0%, and the intensity of the thermal stability at 150 ℃ is improved from 58.9% to 67.0%.

[0018] The red nitride fluorescent powder is prepared by a high-temperature solid-phase method, and has the advantages of simple preparation method, easy operation, high controllability, stable performance and easy industrial production. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 XRD patterns (a-d correspond to examples 1-4, respectively) and a standard pattern (s) of the fluorescent powders prepared in examples 1-4;

[0020] Figure 2 Excitation and emission spectra (a-d correspond to examples 1-4, respectively) of the fluorescent powders prepared in examples 1-4;

[0021] Figure 3 Figure 6 is a graph showing the emission spectrum of the phosphor prepared in Example 1 as a function of temperature;

[0022] Figure 4 Figure 7 is a graph showing the performance of the phosphor prepared in Example 1 under high power blue laser excitation, where (a) is a plot of luminous flux of a rotating phosphor wheel packaged with the phosphor prepared in Example 1 as a function of incident laser power density; and (b) is a graph showing the emission spectrum of the phosphor prepared in Example 1 at different laser power excitation;

[0023] Figure 5 Figure 8 is a graph showing the XRD pattern of the phosphor prepared in Examples 5-6 (a-b correspond to Examples 5-6, respectively) and a standard pattern (s);

[0024] Figure 6 Figure 9 is a graph showing the excitation spectrum and emission spectrum of the phosphor prepared in Examples 5-6 (a-b correspond to Examples 5-6, respectively);

[0025] Figure 7 Figure 10 is a graph showing the XRD pattern of the phosphor prepared in Comparative Example 1 and a standard pattern;

[0026] Figure 8 Figure 11 is a graph showing the excitation spectrum and emission spectrum of the phosphor prepared in Comparative Example 1;

[0027] Figure 9 Figure 12 is a graph showing the luminescence thermal stability of the phosphor prepared in Example 1 compared to the phosphor prepared in Comparative Example 1. DETAILED DESCRIPTION

[0028] In the present application, unless otherwise specified, the required raw materials or reagents are commercially available and well known to those skilled in the art.

[0029] The present application provides a red nitride phosphor having a chemical composition of Sr2[Mg 1-x Li x Al 5-x Si x N7]:yEu 2+ ((denoted as SMAN-xLS:yEu 2+ )), where 0.001≤x≤0.50 and 0.0005≤y≤0.20.

[0030] In the present application, it is preferred that x=0.02-0.4, more preferably 0.1-0.3, and further preferably 0.1, and y=0.01-0.06, more preferably 0.03-0.05.

[0031] The present application provides a method for preparing the red nitride phosphor described in the above technical solution, comprising the following steps:

[0032] The nitrogen-containing Sr source, the nitrogen-containing Mg source, the nitrogen-containing Al source, the nitrogen-containing Si source, the Li source and the Eu source are mixed according to the required stoichiometric ratio, and then grinded to obtain a mixture;

[0033] After sintering the mixture, the mixture is grinded and sieved to obtain the red nitride fluorescent powder.

[0034] In the present application, the nitrogen-containing Sr source is preferably strontium nitride; the nitrogen-containing Mg source is preferably magnesium nitride; the nitrogen-containing Al source is preferably aluminum nitride; and the nitrogen-containing Si source is preferably silicon nitride.

[0035] In the present application, the Li source is preferably lithium nitride or lithium aluminum hydride; and the Eu source is preferably europium fluoride, europium nitride or europium oxide.

[0036] The present application preferably mixes all the materials in a glove box in an air-tight manner to form a mixture, and then grinds the mixture to obtain the mixture; the grinding is not particularly limited in the present application, and can be performed according to the processes well known in the art.

[0037] The present application preferably sintering the mixture in a tungsten crucible, a molybdenum crucible or a boron nitride crucible.

[0038] In the present application, the sintering pressure is preferably 0-1.0 MPa, more preferably 0.5 MPa, and the sintering atmosphere is preferably nitrogen or a nitrogen-hydrogen mixed gas.

[0039] In the present application, the nitrogen-hydrogen mixed gas is preferably composed of 90% nitrogen and 10% hydrogen by volume.

[0040] In the present application, the sintering temperature is preferably 1100-1600°C, more preferably 1200-1500°C, and more preferably 1300°C, and the holding time is preferably 2-20 h, more preferably 5-15 h, and further preferably 6-10 h.

[0041] After sintering, the present application preferably cools to room temperature, grinds the obtained sintering product, and then sieves the grinded product to obtain the red nitride fluorescent powder; the grinding and sieving are not particularly limited in the present application, and can be performed according to the processes well known in the art.

[0042] The present application provides the application of the red nitride fluorescent powder in the above technical solution or the red nitride fluorescent powder prepared by the preparation method in the above technical solution in a laser display device of blue light laser.

[0043] The present application provides the application of the red nitride fluorescent powder in the above technical solution or the red nitride fluorescent powder prepared by the preparation method in the above technical solution in a liquid crystal display device excited by blue light.

[0044] The application has no special limitation on the method of the application, which can be applied according to the methods well known in the art.

[0045] The technical solutions provided by the application will be described in detail below in combination with the embodiments, but they should not be understood as limitations on the protection scope of the application.

[0046] Example 1

[0047] According to the chemical formula SMAN-0.1LS:0.01Eu 2+ The stoichiometric ratios of Sr3N2, Mg3N2, Li3N, Si3N4, AlN and EuF3 (the purity of all raw materials is more than 99.5%) in the formula were weighed, the raw materials were mixed to form a mixture, and then the mixture was grinded to be uniform, and then was placed in a tungsten crucible and put into a high-temperature and high-pressure furnace to be sintered under a nitrogen atmosphere at a sintering pressure of 0.5 MPa at 1300°C for 6 h, and then was cooled to room temperature, grinded and sieved to obtain red nitride fluorescent powder SMAN-0.1LS:0.01Eu. 2+ (i.e. Sr2[Mg 1-x Li x Al 5-x Si x N7]:yEu 2+ In the formula, x=0.1 and y=0.01.

[0048] Figure 1 In the formula, (a, s) is the XRD pattern of the fluorescent powder prepared in Example 1 and the calculated standard pattern, and (b) is the standard pattern of SMAN. Figure 1 As can be seen from the formula, the XRD pattern of the fluorescent powder prepared in Example 1 is compared with the standard pattern of the standard SMAN, and it can be seen that most of the diffraction peaks are shifted to a large angle due to lattice contraction, and no impurity peak is present, which indicates that the substitution ions successfully enter the lattice, i.e. the fluorescent powder synthesized in Example 1 is single-phase and has high purity.

[0049] Figure 2 In the formula, (a) is the excitation spectrum and the emission spectrum of the fluorescent powder prepared in Example 1, Figure 2 In the formula, the inset is a partial enlarged view of the emission spectrum. Figure 2 In the formula, the monitoring wavelength of the excitation spectrum of (a) is 654 nm, and it can be seen that the fluorescent powder prepared in Example 1 can be excited by wavelengths in the range of 250-380 nm and 400-500 nm, the excitation spectrum is a wide spectrum, covering the ultraviolet and blue light regions, and the excitation peak is located near 460 nm, the spectral peak value is high, which indicates that the fluorescent powder prepared in Example 1 can be effectively excited by blue light. Figure 2 In the formula, the excitation wavelength of the emission spectrum of (a) is 460 nm, and the emission peak is Eu 2+The emission peak of the phosphor sample prepared in Example 1 is located at about 654 nm, and the FWHM is 79 nm. The external quantum efficiency of the phosphor sample prepared in Example 1 is 42.0%. The above shows that the phosphor prepared in Example 1 is suitable for red phosphor for high color gamut laser display.

[0050] Figure 3 The emission spectrum of the phosphor prepared in Example 1 changes with temperature. It can be seen that the luminescence intensity of the phosphor gradually decreases with the increase of temperature. The intensity at 100°C can maintain 78.7% of the intensity at room temperature (the working temperature of the phosphor wheel device packaged with the phosphor sample is 50-100°C).

[0051] Figure 4 The performance of the phosphor prepared in Example 1 under high-power blue laser excitation, wherein (a) is a curve graph of the luminous flux of the rotating phosphor wheel packaged with the phosphor prepared in Example 1 with the increase of incident laser power density. As shown in (a) of Figure 4 With the increase of laser power, the device has luminescence saturation, which is due to the fact that the heat quenching cannot be completely eliminated, and more importantly, due to the laser excitation quenching. Although it is impossible to avoid luminescence saturation, the luminescence saturation threshold of the phosphor sample prepared in Example 1 is very high, reaching 52.22 W / mm 2 , which is higher than the saturation threshold of all existing red phosphors, as shown in Table 1. Figure 4 (b) shows the emission spectrum of the phosphor sample prepared in Example 1 under different laser power excitation. With the increase of laser power, the emission intensity of the phosphor sample prepared in Example 1 increases before reaching the saturation threshold, and decreases after exceeding the saturation threshold.

[0052] Table 1 Comparison of the performance of laser excitation of the phosphor prepared in Example 1 with existing phosphors

[0053]

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[0063] Example 2

[0064] According to the chemical formula SMAN-0.2LS:0.01Eu 2+ The stoichiometric ratio of each raw material was weighed for Sr3N2, Mg3N2, Li3N, Si3N4, AlN and EuF3 (the purity of all raw materials was above 99.5%), the raw materials were mixed to form a mixture, and after grinding and mixing uniformly, the mixture was placed in a tungsten crucible and put into a high-temperature and high-pressure furnace to be sintered under a nitrogen atmosphere at a sintering pressure of 0.5 MPa at 1300°C for 6 h, and then cooled to room temperature, ground, and sieved to obtain red nitride fluorescent powder SMAN-0.2LS:0.01Eu. 2+ (i.e. Sr2[Mg 1- x Li x Al 5-x Si x N7]:yEu 2+ , x = 0.2, y = 0.01).

[0065] Figure 1 In the XRD pattern of the fluorescent powder prepared in Example 2 (b, s) and the calculated standard pattern, from Figure 1 As can be seen from the comparison of the XRD pattern of the fluorescent powder prepared in Example 2 with the standard pattern of the standard SMAN, most of the diffraction peaks are shifted to a large angle due to lattice contraction, and no impurity peaks are present, indicating that the substitution ions have successfully entered the lattice, i.e. the fluorescent powder synthesized in Example 2 is single-phase and has high purity.

[0066] Figure 2 In the excitation spectrum and emission spectrum of the fluorescent powder prepared in Example 2 (b). Figure 2 The monitoring wavelength of the excitation spectrum of (b) is 651 nm, and it can be seen that the fluorescent powder prepared in Example 2 can be excited by wavelengths in the range of 250-380 nm and 400-500 nm, and the excitation spectrum is a broad spectrum covering the ultraviolet and blue light regions, and the excitation peak is located near 460 nm, with a high spectral peak value, indicating that the fluorescent powder prepared in Example 2 can be effectively excited by blue light. Figure 2 In the emission spectrum of (b), the excitation wavelength is 460 nm, and the emission peak is the emission peak of Eu 2+ , with a peak value near 651 nm and a FWHM of 79 nm, indicating that the fluorescent powder prepared in Example 2 is suitable for use as a red fluorescent powder for high color gamut laser display.

[0067] Example 3

[0068] According to the chemical formula SMAN-0.3LS:0.01Eu 2+The raw materials Sr3N2, Mg3N2, Li3N, Si3N4, AlN and EuF3 (purity of all raw materials is above 99.5%) were weighed according to stoichiometric ratio, mixed to form a mixture, grinded to be uniform, placed in a tungsten crucible, put into a high temperature and high pressure furnace, sintered at 1300℃ for 6h under nitrogen atmosphere, sintering pressure is 0.5MPa, then cooled to room temperature, grinded, sieved, to obtain red nitride fluorescent powder SMAN-0.3LS:0.01Eu. 2+ (i.e. Sr2[Mg 1- x Li x Al 5-x Si x N7]:yEu 2+ , x=0.3, y=0.01).

[0069] Figure 1 In the figure (c, s), the XRD pattern of the fluorescent powder prepared in Example 3 and the calculated standard pattern are shown, from which Figure 1 As can be seen from the figure, the XRD pattern of the fluorescent powder prepared in Example 3 is compared with the standard pattern of the standard SMAN, it can be seen that due to the lattice shrinkage, most of the diffraction peaks are shifted to large angles, and no impurity peak appears, which indicates that the substitution ions successfully enter the lattice, i.e. the fluorescent powder synthesized in Example 3 is single-phase and high-purity.

[0070] Figure 2 In the figure (c), the excitation spectrum and the emission spectrum of the fluorescent powder prepared in Example 3 are shown. Figure 2 The monitoring wavelength of the excitation spectrum of the figure (c) is 649nm, it can be seen that the fluorescent powder prepared in Example 3 can be excited by the wavelength in the range of 250-380nm and 400-500nm, the excitation spectrum is a wide spectrum, covering the ultraviolet and blue light regions, the excitation peak is near 460nm, the spectral peak value is high, which indicates that the fluorescent powder prepared in Example 3 can be effectively excited by blue light; Figure 2 In the emission spectrum of the figure (c), the excitation wavelength is 460nm, the emission peak is the emission peak of Eu 2+ , the emission peak is near 649nm, and the FWHM is 79nm, which indicates that the fluorescent powder prepared in Example 3 is suitable for red fluorescent powder for high color gamut laser display.

[0071] Example 4

[0072] According to the chemical formula SMAN-0.4LS:0.01Eu 2+The raw materials Sr3N2, Mg3N2, Li3N, Si3N4, AlN and EuF3 (purity of all raw materials is above 99.5%) were weighed according to stoichiometric ratio, mixed to form a mixture, grinded to be uniform, placed in a tungsten crucible, put into a high temperature and high pressure furnace, sintered at 1300℃ for 6h under nitrogen atmosphere, sintering pressure is 0.5MPa, then cooled to room temperature, grinded, sieved, to obtain red nitride fluorescent powder SMAN-0.4LS:0.01Eu. 2+ (i.e. Sr2[Mg 1- x Li x Al 5-x Si x N7]:yEu 2+ , x=0.4, y=0.01).

[0073] Figure 1 (d, s) is the XRD pattern of the fluorescent powder prepared in Example 4 and the calculated standard pattern, from Figure 1 As can be seen from the comparison of the XRD pattern of the fluorescent powder prepared in Example 4 and the standard pattern of the standard SMAN, most of the diffraction peaks are shifted to a large angle due to lattice shrinkage, and no impurity peak appears, which indicates that the substitution ions successfully enter the lattice, i.e. the fluorescent powder synthesized in Example 4 is single-phase and has high purity.

[0074] Figure 2 (d) is the excitation spectrum and emission spectrum of the fluorescent powder prepared in Example 4. Figure 2 The monitoring wavelength of the excitation spectrum of (d) is 647nm, and it can be seen that the fluorescent powder prepared in Example 4 can be excited by wavelengths in the range of 250-380nm and 400-500nm, the excitation spectrum is a wide spectrum, covering the ultraviolet and blue light regions, and the excitation peak is located near 460nm, with high spectral peak value, indicating that the fluorescent powder prepared in Example 4 can be effectively excited by blue light. Figure 2 In the emission spectrum of (d), the excitation wavelength is 460nm, and the emission peak is the emission peak of Eu 2+ , with emission peak located near 647nm and FWHM of 78nm, indicating that the fluorescent powder prepared in Example 4 is suitable for red fluorescent powder for high color gamut laser display.

[0075] Example 5

[0076] According to the chemical formula SMAN-0.02LS:0.05Eu 2+The raw materials of Sr3N2, Mg3N2, Li3N, Si3N4, AlN and EuF3 (purity of all raw materials is above 99.5%) are weighed according to stoichiometric ratio, mixed, grinded and uniformly mixed, then put into a tungsten crucible and placed into a high temperature and high pressure furnace under nitrogen atmosphere, sintered at 1300℃ for 6h under a sintering pressure of 0.5MPa, then cooled to room temperature, grinded, sieved, and red nitride fluorescent powder SMAN-0.02LS:0.05Eu is obtained. 2+ (i.e. Sr2[Mg 1-x Li x Al 5-x Si x N7]:yEu 2+ , x=0.02, y=0.05).

[0077] Figure 5 In (a, s), the XRD pattern of the fluorescent powder prepared in Example 5 and the calculated standard pattern are shown, and the standard pattern of SMAN is shown in (b). Figure 5 As can be seen from the comparison of the XRD pattern of the fluorescent powder prepared in Example 5 and the standard pattern of SMAN, no impurity peak appears, i.e. the fluorescent powder synthesized in Example 5 is single phase and has high purity.

[0078] Figure 6 In (a), the excitation spectrum and the emission spectrum of the fluorescent powder prepared in Example 5 are shown. Figure 6 The monitoring wavelength of the excitation spectrum of (a) is 676nm, and it can be seen that the fluorescent powder prepared in Example 5 can be excited by wavelengths in the range of 250-380nm and 400-500nm, the excitation spectrum is a wide spectrum, covering the ultraviolet and blue light regions, and the excitation peak is located near 460nm, the spectral peak value is high, indicating that the fluorescent powder prepared in Example 5 can be effectively excited by blue light. Figure 6 In the emission spectrum of (a), the excitation wavelength is 460nm, and the emission peak is the emission peak of Eu 2+ , the emission peak is located near 676nm, the FWHM is 86nm, and the color coordinates are (0.7065, 0.2934), indicating that the fluorescent powder prepared in Example 5 is suitable for use as a red fluorescent powder for high color gamut laser display.

[0079] Example 6

[0080] According to the chemical formula SMAN-0.02LS:0.06Eu 2+The raw materials of Sr3N2, Mg3N2, Li3N, Si3N4, AlN and EuF3 (purity of all raw materials is above 99.5%) were weighed according to stoichiometric ratio, mixed, grinded and uniformly mixed, then put into a tungsten crucible and placed into a high temperature and high pressure furnace under nitrogen atmosphere, sintered at 1300℃ for 6h under a sintering pressure of 0.5MPa, then cooled to room temperature, grinded, sieved, and red nitride fluorescent powder SMAN-0.02LS:0.06Eu was obtained. 2+ (i.e. Sr2[Mg 1-x Li x Al 5-x Si x N7]:yEu 2+ , x=0.02, y=0.06).

[0081] Figure 5 In the XRD pattern of the fluorescent powder prepared in Example 6 (b, s) and the calculated standard pattern, from Figure 5 As can be seen from the comparison of the XRD pattern of the fluorescent powder prepared in Example 6 with the standard pattern of the standard SMAN, no impurity peak appears, i.e. the fluorescent powder synthesized in Example 6 is single-phase and has high purity.

[0082] Figure 6 In the excitation spectrum and emission spectrum of the fluorescent powder prepared in Example 6 (b). Figure 6 The monitoring wavelength of the excitation spectrum of (b) is 680nm, and it can be seen that the fluorescent powder prepared in Example 6 can be excited by wavelengths in the range of 250-380nm and 400-500nm, the excitation spectrum is a wide spectrum covering the ultraviolet and blue light regions, the excitation peak is located near 460nm, the spectral peak value is high, indicating that the fluorescent powder prepared in Example 6 can be effectively excited by blue light. Figure 6 In the emission spectrum of (b), the excitation wavelength is 460nm, and the emission peak is the emission peak of Eu 2+ , the emission peak is located near 680nm, the FWHM is 87nm, and the color coordinates are (0.7075, 0.2924), indicating that the fluorescent powder prepared in Example 6 is suitable for use as a red fluorescent powder for laser display.

[0083] Comparative Example 1

[0084] According to the chemical formula SMAN (Sr2[Mg1Al5N7]:yEu 2+ ):0.01Eu 2+The stoichiometric ratio of each raw material was measured for Sr3N2, Mg3N2, AlN and EuF3 (the purity of all raw materials was more than 99.5%), the raw materials were mixed to form a mixture, and after grinding and mixing uniformly, the mixture was placed in a tungsten crucible and put into a high-temperature high-pressure furnace under a nitrogen atmosphere, sintered at a pressure of 0.5 MPa at 1300°C for 6 h, and then cooled to room temperature, ground and sieved to obtain a red nitride fluorescent powder SMAN:0.01Eu. 2+ .

[0085] Figure 7 The XRD pattern of the fluorescent powder prepared in Comparative Example 1 and the calculated standard pattern can be seen from FIG. 2. Figure 7 It can be seen from the comparison of the XRD pattern of the fluorescent powder prepared in Comparative Example 1 with the standard pattern of the standard SMAN that no impurity peak appears, indicating that the fluorescent powder synthesized in Comparative Example 1 is single-phase and has high purity.

[0086] Figure 8 The excitation spectrum and the emission spectrum of the fluorescent powder prepared in Comparative Example 1 are shown in FIG. 3. Figure 8 The monitoring wavelength of the excitation spectrum in FIG. 3 is 657 nm, and it can be seen that the fluorescent powder prepared in Example 1 can be excited by wavelengths in the range of 250-380 nm and 400-500 nm, and the excitation peak is located near 460 nm. Figure 8 In the emission spectrum in FIG. 3, the excitation wavelength is 460 nm, and the emission peak is the emission peak of Eu 2+ , and the emission peak value is located near 657 nm, and the FWHM is 80 nm. In addition, it can be calculated that the external quantum efficiency of the fluorescent powder sample prepared in Comparative Example 1 is only 28.1%, which is significantly lower than that of the sample prepared in Example 1 (42.0%).

[0087] Figure 9 The luminescent thermal stability of the fluorescent powder prepared in Example 1 and Comparative Example 1 was compared, and it can be seen that the luminescent thermal stability of the fluorescent powder prepared in Comparative Example 1 was significantly worse than that of the fluorescent powder prepared in Example 1 at 100-225°C, and the intensity of the fluorescent powder prepared in Example 1 at 150°C was increased from 58.9% of Comparative Example 1 to 67.0%.

[0088] The above only describes the preferred embodiments of the present application, and it should be noted that those skilled in the art can make several improvements and refinements without departing from the principles of the present application, and these improvements and refinements should also be considered within the scope of protection of the present application.

Claims

1. A red nitride phosphor, characterized by, Chemical composition: Sr2[Mg 1-x Li x Al 5-x Si x N7]:yEu 2+ wherein 0.001≤x≤0.50, 0.0005≤y≤0.

20.

2. The red nitride phosphor of claim 1, wherein, x=0.02-0.4, y=0.01-0.

06.

3. The method for preparing the red nitride phosphor according to claim 1 or 2, characterized in that, The method comprises the following steps: According to the required stoichiometric ratio, the nitrogen-containing Sr source, the nitrogen-containing Mg source, the nitrogen-containing Al source, the nitrogen-containing Si source, the Li source and the Eu source are mixed and ground to obtain a mixture; After sintering the mixture, the mixture is ground and sieved to obtain the red nitride fluorescent powder.

4. The production method according to claim 3, characterized by, The Li source is lithium nitride or lithium aluminum hydride; the Eu source is europium fluoride, europium nitride or europium oxide.

5. The production method according to claim 3 or 4, characterized by, The sintering pressure is 0-1.0 MPa, and the sintering atmosphere is nitrogen or nitrogen-hydrogen mixed gas.

6. The preparation method according to claim 5, characterized in that, The nitrogen-hydrogen mixed gas is composed of 90% nitrogen and 10% hydrogen by volume percentage.

7. The preparation method according to claim 6, characterized in that, The sintering temperature is 1100-1600°C, and the holding time is 2-20 h.

8. The use of the red nitride fluorescent powder of claim 1 or 2 or prepared by the method of any one of claims 3-7 in a blue light excited laser display device.

9. The use of the red nitride fluorescent powder of claim 1 or 2 or prepared by the method of any one of claims 3-7 in a blue light excited liquid crystal display.

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