Red nitride phosphor, and preparation method therefor and use thereof

Abstract

The present invention relates to the technical field of rare earth luminescent materials and provides a red nitride phosphor, and a preparation method therefor and a use thereof. The chemical composition of the red nitride phosphor of the present invention is Sr2[Mg1-xLixAl5-xSixN7]:yEu2+, wherein 0.001≤x≤0.50 and 0.0005≤y≤0.20. The phosphor is based on a nitride system, exhibits strong light absorption of blue light at 400-500 nm, has an excitation peak value of about 460 nm, can be effectively excited by blue laser light, can emit red fluorescence under blue light excitation, has an emission peak value adjustable in the range of 635 nm to 685 nm and a full width at half maximum adjustable in the range of 75 nm to 90 nm, and greatly contributes to high color gamut in display devices. The phosphor, when used in various laser display devices using blue light high-power lasers as excitation sources, has the advantages of strong luminous brightness, high luminous efficiency, and stable physical and chemical properties.

Description

A red nitride phosphor, its preparation method and application Technical Field

[0001] This invention relates to the field of rare earth luminescent materials technology, and in particular to a red nitride phosphor, its preparation method, and its application. Background Technology

[0002] The development and advancement of display technology have transformed people's lives, allowing the medium for long-distance communication to evolve from purely text and sound to vivid images. For display devices, high-efficiency light sources are increasingly being used in monitors. Display devices require high-efficiency, narrow-peak emission phosphors, meaning the phosphors must have a narrow emission band at half maximum (FWHM), a specific peak position, high quantum efficiency, and good thermal stability. Currently, commercial liquid crystal displays (LCDs) use a backlight source employing "blue InGaN chip + β-SiAlON:Eu" technology. 2+ (λ em =540nm; FWHM=55nm) Green phosphor + K2SiF6:Mn 4+ (λ emThe packaging solution using "630nm (peak) red phosphor" is currently the commercially available phosphor-based solution with the largest color gamut area. The color gamut is primarily determined by the color coordinates of the red, green, and blue (RGB) light emitted by the light-emitting diode (LED) source. Traditional display technology uses LCDs, whose core technology is LED backlighting. However, LEDs as backlights have several drawbacks, such as large optical extension, low brightness, and insufficient color purity, which greatly limits their application in high-brightness, wide-color-gamut display fields, such as cinemas and projection equipment. Laser light source technology, which has emerged in recent years, belongs to solid-state light source technology, just like LED light source technology. Due to its advantages such as long lifespan, low energy consumption, and environmental friendliness, it is considered by academia and industry to be the most promising green light source of the 21st century. Because lasers have a short emission bandwidth, they offer high efficiency, small size, and lower efficiency per unit laser diode. The diode (LD) region exhibits high photon output and high brightness, making it suitable for laser-excited phosphor materials to achieve high color gamut display. While combining red, green, and blue lasers can achieve high-purity laser displays, current green laser devices are not only expensive but also suffer from a problem known as "green defects," and the design of multi-emission systems naturally increases costs. Therefore, using blue lasers with multi-color phosphor materials for display is more efficient and has greater research value. For devices using phosphors, the quality of the phosphor is crucial to device performance. Laser display technology still primarily uses phosphors from traditional LED technology; however, considering the brightness saturation phenomenon of phosphors under high power density light sources, the requirements for laser phosphors differ from those for LED phosphors.

[0003] For narrow-peak red phosphors, the narrowest Eu peak currently available is... 2+ Activated Sr[LiAl3N4]:Eu 2+ The phosphor emits at 650 nm and FWHM at 50 nm, but its water stability is very poor, severely degrading the performance of the packaged devices. Therefore, Mn 4+ Activated luminescent materials (spike emission) have become the preferred phosphors for wide color gamut displays. Among them, commercially available wide color gamut red phosphors use K2SiF6:Mn. 4+ Fluoride systems, as a representative example, exhibit narrow-peak luminescence, but suffer from environmentally unfriendly preparation processes, low external quantum efficiency (<55%), and poor moisture resistance, all of which urgently require solutions. More importantly, for laser source technology, Mn... 2+ and Mn 4+Activated narrow-peak red phosphors suffer from severe photo-saturation and thermal saturation problems, with photo-saturation thresholds and luminous efficacy too low to meet the requirements of laser display applications. Overall, currently developed narrow-peak red luminescent materials, both domestically and internationally, generally suffer from low luminous efficacy and poor reliability. Therefore, high-efficiency phosphors with efficient narrow-peak emission have become a key area of ​​technological research and a hot topic in the display market. There is an urgent need to develop effective construction methods for high-efficiency narrow-peak phosphors for displays, overcoming the bottleneck of a lack of key materials. Summary of the Invention

[0004] The purpose of this invention is to provide a red nitride phosphor, its preparation method and application. The red nitride phosphor has excellent red light emissivity, its emission can achieve a high color gamut, and it is easy to synthesize.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0006] This invention provides a red nitride phosphor with the chemical composition Sr2[Mg]. 1-x Li x Al 5-x Si x N7]:yEu 2+ Where 0.001≤x≤0.50, 0.0005≤y≤0.20.

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

[0008] This invention provides a method for preparing the red nitride phosphor described in the above technical solution, comprising the following steps:

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

[0010] After sintering the mixture, it is then ground and sieved to obtain red nitride phosphor.

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

[0012] Preferably, the sintering pressure is 0 to 1.0 MPa, and the sintering atmosphere is nitrogen or a nitrogen-hydrogen mixture.

[0013] Preferably, the nitrogen-hydrogen mixture is composed of 90% nitrogen and 10% hydrogen by volume percentage.

[0014] Preferably, the sintering temperature is 1100–1600℃, and the holding time is 2–20h.

[0015] This invention provides the application of the red nitride phosphor described in the above-described technical solution or the red nitride phosphor prepared by the above-described preparation method in blue laser display devices.

[0016] This invention provides the application of the red nitride phosphor described in the above-described technical solution or the red nitride phosphor prepared by the above-described preparation method in a blue light-excited liquid crystal display.

[0017] This invention provides a red nitride phosphor with the chemical composition Sr2[Mg]. 1-x Li x Al 5-x Si x N7]:yEu 2+ Where 0.001≤x≤0.50, 0.0005≤y≤0.20. This invention relates to Sr2[MgAl5N7]:Eu 2+ The addition of Li and Si balances the charge and causes lattice contraction, thereby increasing lattice rigidity. Increased lattice rigidity improves quantum efficiency and luminescence thermal stability. This phosphor is a nitride system with strong blue light absorption in the 400–500 nm range, an excitation peak value around 460 nm, and can be effectively excited by blue lasers. Under blue light excitation, it emits red fluorescence with an tunable peak value of 635–685 nm and a tunable full width at half maximum (FWHM) of 75–90 nm, contributing significantly to high color gamut in display devices. Using this phosphor in various laser display devices using high-power blue lasers as excitation sources demonstrates advantages such as high luminous brightness, high luminous efficiency, and stable physicochemical properties, meeting the performance requirements of high-performance devices. The results of the examples show that, compared to the sample without Li and Si, the SMAN: 0.01 Eu 2+ The sample with both Li and Si added was SMAN-0.1LS:0.01Eu. 2+ The external quantum efficiency increased from 28.1% to 42.0%, and the thermal stability at 150°C increased from 58.9% to 67.0%.

[0018] The red nitride phosphor of the present invention is prepared by a high-temperature solid-state method. The preparation method is simple, easy to operate, highly controllable, stable in performance, and easy to industrialize. Attached Figure Description

[0019] Figure 1 shows the XRD patterns of the phosphors prepared in Examples 1 to 4 (a to d correspond to Examples 1 to 4 respectively) and the standard patterns (s);

[0020] Figure 2 shows the excitation and emission spectra of the phosphors prepared in Examples 1 to 4 (a to d correspond to Examples 1 to 4 respectively);

[0021] Figure 3 shows the emission spectrum of the phosphor prepared in Example 1 as a function of temperature;

[0022] Figure 4 shows the performance of the phosphor prepared in Example 1 under high-power blue laser excitation, where (a) is a graph of the luminous flux of the rotating phosphor wheel encapsulated with the phosphor prepared in Example 1 as the incident laser power density increases; and (b) is the emission spectrum of the phosphor sample prepared in Example 1 under different laser power excitation.

[0023] Figure 5 shows the XRD patterns of the phosphors prepared in Examples 5-6 (a-b correspond to Examples 5-6 respectively) and the standard patterns (s);

[0024] Figure 6 shows the excitation and emission spectra of the phosphors prepared in Examples 5 and 6 (a to b correspond to Examples 5 and 6 respectively);

[0025] Figure 7 shows the XRD pattern and standard pattern of the phosphor prepared in Comparative Example 1;

[0026] Figure 8 shows the excitation and emission spectra of the phosphor prepared in Comparative Example 1.

[0027] Figure 9 is a comparison of the luminescence thermal stability of the phosphors prepared in Example 1 and Comparative Example 1. Detailed Implementation

[0028] In this invention, unless otherwise specified, the raw materials or reagents required for preparation are all commercially available products well known to those skilled in the art.

[0029] This invention provides a red nitride phosphor with the chemical composition Sr2[Mg]. 1-x Li x Al 5-x Si x N7]:yEu 2+ ((referred to as SMAN-xLS:yEu) 2+ ), where 0.001≤x≤0.50, 0.0005≤y≤0.20.

[0030] In this invention, x is preferably 0.02 to 0.4, more preferably 0.1 to 0.3, and even more preferably 0.1; y is preferably 0.01 to 0.06, and more preferably 0.03 to 0.05.

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

[0032] According to the required stoichiometric ratio, nitrogen-containing Sr source, nitrogen-containing Mg source, nitrogen-containing Al source, nitrogen-containing Si source, Li source and Eu source are mixed and ground to obtain a mixture.

[0033] After sintering the mixture, it is then ground and sieved to obtain red nitride phosphor.

[0034] In this invention, 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 this invention, the Li source is preferably lithium nitride or lithium aluminum hydride; the Eu source is preferably europium fluoride, europium nitride, or europium oxide.

[0036] The present invention preferably involves mixing all materials in an air-isolated glove box to form a mixture, then grinding the mixture to obtain a final product. The present invention does not impose any particular limitation on the grinding process, which can be carried out according to a process well known in the art.

[0037] In this invention, the mixture is preferably placed in a tungsten crucible, a molybdenum crucible, or a boron nitride crucible for sintering.

[0038] In this invention, the sintering pressure is preferably 0 to 1.0 MPa, more preferably 0.5 MPa, and the sintering atmosphere is preferably nitrogen or a nitrogen-hydrogen mixture.

[0039] In this invention, the nitrogen-hydrogen mixture is preferably composed of 90% nitrogen and 10% hydrogen by volume percentage.

[0040] In this invention, the sintering temperature is preferably 1100-1600℃, more preferably 1200-1500℃, even more preferably 1300℃, and the holding time is preferably 2-20h, more preferably 5-15h, and even more preferably 6-10h.

[0041] After sintering, the present invention preferably cools to room temperature, grinds the obtained sintered product, and then sieves it to obtain red nitride phosphor. The present invention does not have any special limitations on the grinding and sieving, and can be carried out according to the process known in the art.

[0042] This invention provides the application of the red nitride phosphor described in the above-described technical solution or the red nitride phosphor prepared by the above-described preparation method in blue laser display devices.

[0043] This invention provides the application of the red nitride phosphor described in the above-described technical solution or the red nitride phosphor prepared by the above-described preparation method in a blue light-excited liquid crystal display.

[0044] The present invention does not impose any special limitations on the method of application described herein; it may be applied in accordance with methods known in the art.

[0045] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0046] Example 1

[0047] According to the chemical formula SMAN-0.1LS:0.01Eu 2+ The stoichiometric ratios of the raw materials were as follows: Sr3N2, Mg3N2, Li3N, Si3N4, AlN, and EuF3 (all raw materials with a purity of ≥99.5%). The raw materials were mixed to form a homogeneous mixture, ground thoroughly, and then placed in a tungsten crucible. The mixture was then placed in a high-temperature, high-pressure furnace under a nitrogen atmosphere at a sintering pressure of 0.5 MPa and a firing temperature of 1300℃ for 6 hours. After cooling to room temperature, the mixture was ground and sieved to obtain the red nitride phosphor SMAN-0.1LS:0.01Eu. 2+ (i.e., Sr2[Mg) 1-x Li x Al 5-x Si x N7]:yEu 2+ In the given information, x = 0.1, y = 0.01.

[0048] Figure 1 (a, s) shows the XRD pattern of the phosphor prepared in Example 1 and the calculated standard pattern. As can be seen from Figure 1, the XRD pattern of the phosphor prepared in Example 1 is compared with the standard SMAN pattern. Due to lattice contraction, most of the diffraction peaks shift to larger angles, and no impurity peaks appear. This indicates that the substituted ions have successfully entered the lattice. In other words, the phosphor synthesized in Example 1 is a single phase with high purity.

[0049] Figure 2(a) shows the excitation and emission spectra of the phosphor prepared in Example 1. The inset in Figure 2 is a magnified view of the emission spectrum. The monitoring wavelength of the excitation spectrum in Figure 2(a) is 654 nm. It can be seen that the phosphor prepared in Example 1 can be excited by wavelengths in the ranges of 250-380 nm and 400-500 nm. The excitation spectrum is a broad spectrum covering both ultraviolet and blue light regions. The excitation peak is located near 460 nm, and the high spectral peak indicates that the phosphor prepared in Example 1 can be effectively excited by blue light. In the emission spectrum of Figure 2(a), the excitation wavelength is 460 nm, and the emission peak is Eu. 2+ The emission peak is located around 654 nm, and the FWHM is 79 nm. The external quantum efficiency of the phosphor sample prepared in Example 1 is 42.0%. This indicates that the phosphor prepared in Example 1 is suitable as a red phosphor for high color gamut laser displays.

[0050] Figure 3 shows the emission spectrum of the phosphor prepared in Example 1 as a function of temperature. It can be seen that the luminescence intensity of the phosphor gradually decreases with increasing temperature. The intensity at 100℃ can be maintained at 78.7% of the intensity at room temperature (the operating temperature of the phosphor wheel device encapsulated with the phosphor sample is 50-100℃).

[0051] Figure 4 shows the performance of the phosphor prepared in Example 1 under high-power blue laser excitation. (a) is a graph showing the luminous flux of the rotating phosphor wheel encapsulated with the phosphor prepared in Example 1 as a function of incident laser power density. As shown in Figure 4(a), the device exhibits luminous saturation with increasing laser power. This is partly due to the incomplete elimination of thermal quenching, but more importantly, due to laser excitation quenching. Although luminous saturation cannot be completely avoided, the phosphor sample prepared in Example 1 has a very high luminous saturation threshold of 52.22 W / mm². 2 The emission intensity of the phosphor sample prepared in Example 1 is superior to the saturation threshold of all existing red phosphors, as shown in Table 1. Figure 4(b) shows the emission spectra of the phosphor sample prepared in Example 1 under different laser power excitation. As the laser power increases, 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 laser excitation performance of the phosphor prepared in Example 1 with that of existing phosphors.

[0053] [1]J.Zhou,Y.Wang,Y.Chen,Y.Zhou,B. L. Zhou, J. Yan, J. Shi, R.-S. Liu, M. Wu, Angewandte Chemie International Edition 2021, 60, 3940-3945.

[0054] [2]HLSi Sc,J.Wang,Chinese Journal of Luminescence 2021,42,1549-1558.

[0055] [3]Y.Zhou,H.Ming,Y.Zhao,Y.Wang,E.Song,Z.Xia,Q.Zhang, Chinese Journal of Luminescence 2021,42,1559-1568.

[0056] [4]Y. Zhou, C. Yu, E. Song, Y. Wang, H. Ming, Z. Xia, Q. Zhang, Advanced Optical Materials 2020, 8, 2000976.

[0057] [5]S. B. Kwon, B. Y. Kim, S. H. Choi, J. H. Yoo, W. H. Kim, J. P. Kim, H. J. Jeong, D. J. Park, B. K. Kang, D. H. Yoon, Y. H. Song, Current Applied Physics 2020, 20, 1281 - 1287.

[0058] [6]Y. Zhang, Z. Zhang, X. Liu, G. Shao, L. Shen, J. Liu, W. Xiang, X. Liang, Chemical Engineering Journal 2020, 401, 125983.

[0059] [7]S. Li, D. Tang, Z. Tian, X. Liu, T. Takeda, N. Hiroaki, F. Xu, Z. Huang, R.-J. Xie, Journal of Materials Chemistry C 2017, 5, 1042 - 1051.

[0060] [8]X. Peng, S. Li, Z. Liu, B. Zhang, Y. Peng, D. Yu, R. Tian, X. Yao, Z. Huang, X. Liu, R.-J. Xie, Journal of the European Ceramic Society 2021, 41, 5650 - 5657.

[0061] [9]T. Hu, L. Ning, Y. Gao, J. Qiao, E. Song, Z. Chen, Y. Zhou, J. Wang, M. S. Molokeev, X. Ke, Z. Xia, Q. Zhang, Light: Science & Applications 2021, 10, 56.

[0062] Example 2

[0063] According to the chemical formula SMAN-0.2LS:0.01Eu 2+The stoichiometric ratios of the raw materials were as follows: Sr3N2, Mg3N2, Li3N, Si3N4, AlN, and EuF3 (all raw materials with a purity of ≥99.5%). The raw materials were mixed to form a homogeneous mixture, then ground and placed in a tungsten crucible. The mixture was then placed in a high-temperature, high-pressure furnace under a nitrogen atmosphere at a sintering pressure of 0.5 MPa and a firing temperature of 1300℃ for 6 hours. After cooling to room temperature, the mixture was ground and sieved to obtain the red nitride phosphor SMAN-0.2LS:0.01Eu. 2+ (i.e., Sr2[Mg) 1-x Li x Al 5-x Si x N7]:yEu 2+ In the given information, x = 0.2, y = 0.01.

[0064] Figure 1 (b, s) shows the XRD pattern of the phosphor prepared in Example 2 and the calculated standard pattern. As can be seen from Figure 1, the XRD pattern of the phosphor prepared in Example 2 is compared with the standard SMAN pattern. Due to lattice contraction, most of the diffraction peaks shift to larger angles, and no impurity peaks appear. This indicates that the substituted ions have successfully entered the lattice. In other words, the phosphor synthesized in Example 2 is a single phase with high purity.

[0065] Figure 2(b) shows the excitation and emission spectra of the phosphor prepared in Example 2. The monitoring wavelength of the excitation spectrum in Figure 2(b) is 651 nm. It can be seen that the phosphor prepared in Example 2 can be excited by wavelengths in the ranges of 250-380 nm and 400-500 nm. The excitation spectrum is a broad spectrum covering both ultraviolet and blue light regions. The excitation peak is located near 460 nm, and the high spectral peak indicates that the phosphor prepared in Example 2 can be effectively excited by blue light. In the emission spectrum of Figure 2(b), the excitation wavelength is 460 nm, and the emission peak is Eu. 2+ The emission peak is located around 651nm, and the FWHM is 79nm, indicating that the phosphor prepared in Example 2 is suitable as a red phosphor for high color gamut laser display.

[0066] Example 3

[0067] According to the chemical formula SMAN-0.3LS:0.01Eu 2+ The stoichiometric ratios of the raw materials were as follows: Sr3N2, Mg3N2, Li3N, Si3N4, AlN, and EuF3 (all raw materials with a purity of ≥99.5%). The raw materials were mixed to form a homogeneous mixture, then ground and placed in a tungsten crucible. The mixture was then placed in a high-temperature, high-pressure furnace under a nitrogen atmosphere at a sintering pressure of 0.5 MPa and a firing temperature of 1300℃ for 6 hours. After cooling to room temperature, the mixture was ground and sieved to obtain the red nitride phosphor SMAN-0.3LS:0.01Eu.2+ (i.e., Sr2[Mg) 1-x Li x Al 5-x Si x N7]:yEu 2+ In the given information, x = 0.3 and y = 0.01.

[0068] Figure 1 (c, s) shows the XRD pattern of the phosphor prepared in Example 3 and the calculated standard pattern. As can be seen from Figure 1, the XRD pattern of the phosphor prepared in Example 3 is compared with the standard SMAN pattern. Due to lattice contraction, most of the diffraction peaks shift to larger angles, and no impurity peaks appear. This indicates that the substituted ions have successfully entered the lattice. In other words, the phosphor synthesized in Example 3 is a single phase with high purity.

[0069] Figure 2(c) shows the excitation and emission spectra of the phosphor prepared in Example 3. The monitoring wavelength of the excitation spectrum in Figure 2(c) is 649 nm. It can be seen that the phosphor prepared in Example 3 can be excited by wavelengths in the ranges of 250-380 nm and 400-500 nm. The excitation spectrum is a broad spectrum covering both ultraviolet and blue light regions. The excitation peak is located near 460 nm, and the high spectral peak indicates that the phosphor prepared in Example 3 can be effectively excited by blue light. In the emission spectrum of Figure 2(c), the excitation wavelength is 460 nm, and the emission peak is Eu. 2+ The emission peak is located near 649 nm, and the FWHM is 79 nm, indicating that the phosphor prepared in Example 3 is suitable as a red phosphor for high color gamut laser display.

[0070] Example 4

[0071] According to the chemical formula SMAN-0.4LS:0.01Eu 2+ The stoichiometric ratios of the raw materials were as follows: Sr3N2, Mg3N2, Li3N, Si3N4, AlN, and EuF3 (all raw materials with a purity of ≥99.5%). The raw materials were mixed to form a homogeneous mixture, then ground and placed in a tungsten crucible. The mixture was then placed in a high-temperature, high-pressure furnace under a nitrogen atmosphere at 1300℃ for 6 hours under a sintering pressure of 0.5 MPa. After cooling to room temperature, the mixture was ground and sieved to obtain the red nitride phosphor SMAN-0.4LS:0.01Eu. 2+ (i.e., Sr2[Mg) 1-x Li x Al 5-x Si x N7]:yEu 2+ In the given information, x = 0.4 and y = 0.01.

[0072] Figure 1 (d, s) shows the XRD pattern of the phosphor prepared in Example 4 and the calculated standard pattern. As can be seen from Figure 1, the XRD pattern of the phosphor prepared in Example 4 is compared with the standard SMAN pattern. Due to lattice contraction, most of the diffraction peaks shift to larger angles, and no impurity peaks appear. This indicates that the substituted ions have successfully entered the lattice. In other words, the phosphor synthesized in Example 4 is a single phase with high purity.

[0073] Figure 2(d) shows the excitation and emission spectra of the phosphor prepared in Example 4. The monitoring wavelength of the excitation spectrum in Figure 2(d) is 647 nm. It can be seen that the phosphor prepared in Example 4 can be excited by wavelengths in the ranges of 250-380 nm and 400-500 nm. The excitation spectrum is a broad spectrum covering both ultraviolet and blue light regions. The excitation peak is located near 460 nm, and the high spectral peak indicates that the phosphor prepared in Example 4 can be effectively excited by blue light. In the emission spectrum of Figure 2(d), the excitation wavelength is 460 nm, and the emission peak is Eu. 2+ The emission peak is located near 647nm, and the FWHM is 78nm, indicating that the phosphor prepared in Example 4 is suitable as a red phosphor for high color gamut laser display.

[0074] Example 5

[0075] According to the chemical formula SMAN-0.02LS:0.05Eu 2+ The stoichiometric ratios of the raw materials were as follows: Sr3N2, Mg3N2, Li3N, Si3N4, AlN, and EuF3 (all raw materials with a purity of ≥99.5%). The raw materials were mixed to form a homogeneous mixture, ground, and then placed in a tungsten crucible. The mixture was then placed in a high-temperature, high-pressure furnace under a nitrogen atmosphere at a sintering pressure of 0.5 MPa and a firing temperature of 1300℃ for 6 hours. After cooling to room temperature, the mixture was ground and sieved to obtain the red nitride phosphor SMAN-0.02LS:0.05Eu. 2+ (i.e., Sr2[Mg) 1-x Li x Al 5-x Si x N7]:yEu 2+ In the given information, x = 0.02, y = 0.05.

[0076] Figure 5 (a, s) shows the XRD pattern of the phosphor prepared in Example 5 and the calculated standard pattern. As can be seen from Figure 5, when the XRD pattern of the phosphor prepared in Example 5 is compared with the standard SMAN pattern, no impurity peaks are observed. This indicates that the phosphor synthesized in Example 5 is single-phase and has high purity.

[0077] Figure 6(a) shows the excitation and emission spectra of the phosphor prepared in Example 5. The monitoring wavelength of the excitation spectrum in Figure 6(a) is 676 nm. It can be seen that the phosphor prepared in Example 5 can be excited by wavelengths in the ranges of 250-380 nm and 400-500 nm. The excitation spectrum is a broad spectrum covering both ultraviolet and blue light regions. The excitation peak is located near 460 nm, and the high spectral peak indicates that the phosphor prepared in Example 5 can be effectively excited by blue light. In the emission spectrum of Figure 6(a), the excitation wavelength is 460 nm, and the emission peak is Eu. 2+ The emission peak is located near 676 nm, the FWHM is 86 nm, and the color coordinates are (0.7065, 0.2934), indicating that the phosphor prepared in Example 5 is suitable as a red phosphor for high color gamut laser display.

[0078] Example 6

[0079] According to the chemical formula SMAN-0.02LS:0.06Eu 2+ The stoichiometric ratios of the raw materials were as follows: Sr3N2, Mg3N2, Li3N, Si3N4, AlN, and EuF3 (all raw materials with a purity of ≥99.5%). The raw materials were mixed to form a homogeneous mixture, ground, and then placed in a tungsten crucible. The mixture was then placed in a high-temperature, high-pressure furnace under a nitrogen atmosphere at a sintering pressure of 0.5 MPa at 1300℃ for 6 hours. After cooling to room temperature, the mixture was ground and sieved to obtain the red nitride phosphor SMAN-0.02LS:0.06Eu. 2+ (i.e., Sr2[Mg) 1-x Li x Al 5-x Si x N7]:yEu 2+ In the given information, x = 0.02, y = 0.06.

[0080] Figure 5 (b, s) shows the XRD pattern of the phosphor prepared in Example 6 and the calculated standard pattern. As can be seen from Figure 5, the XRD pattern of the phosphor prepared in Example 6 is compared with the standard SMAN pattern, and no impurity peaks are found. This means that the phosphor synthesized in Example 6 is single-phase and has high purity.

[0081] Figure 6(b) shows the excitation and emission spectra of the phosphor prepared in Example 6. The monitoring wavelength for the excitation spectrum in Figure 6(b) is 680 nm. It can be seen that the phosphor prepared in Example 6 can be excited by wavelengths in the ranges of 250-380 nm and 400-500 nm. The excitation spectrum is a broad spectrum covering both ultraviolet and blue light regions. The excitation peak is located near 460 nm, and the high spectral peak indicates that the phosphor prepared in Example 6 can be effectively excited by blue light. In the emission spectrum of Figure 6(b), the excitation wavelength is 460 nm, and the emission peak is 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 phosphor prepared in Example 6 is suitable as a red phosphor for laser display.

[0082] Comparative Example 1

[0083] According to the chemical formula SMAN(Sr2[Mg1Al5N7]:yEu) 2+ ):0.01Eu 2+ The stoichiometric proportions of each raw material were as follows: Sr3N2, Mg3N2, AlN, and EuF3 (all raw materials with a purity of ≥99.5%). The raw materials were mixed to form a homogeneous mixture, ground thoroughly, and then placed in a tungsten crucible. The mixture was then placed in a high-temperature, high-pressure furnace under a nitrogen atmosphere at a sintering pressure of 0.5 MPa and a firing temperature of 1300℃ for 6 hours. After cooling to room temperature, the mixture was ground and sieved to obtain a red nitride phosphor (SMAN: 0.01 Eu). 2+ .

[0084] Figure 7 shows the XRD pattern of the phosphor prepared in Comparative Example 1 and the calculated standard pattern. As can be seen from Figure 7, the XRD pattern of the phosphor prepared in Comparative Example 1 is compared with the standard SMAN pattern, and no impurity peaks are found. This indicates that the phosphor synthesized in Comparative Example 1 is single-phase and has high purity.

[0085] Figure 8 shows the excitation and emission spectra of the phosphor prepared in Comparative Example 1. The monitoring wavelength for the excitation spectrum in Figure 8 is 657 nm. It can be seen that the phosphor prepared in Example 1 can be excited by wavelengths in the ranges of 250-380 nm and 400-500 nm, with the excitation peak located near 460 nm. In the emission spectrum of Figure 8, the excitation wavelength is 460 nm, and the emission peak is Eu. 2+ The emission peak is located around 657 nm, and the FWHM is 80 nm. Furthermore, calculations show that the external quantum efficiency of the phosphor sample prepared in Comparative Example 1 is only 28.1%, significantly lower than that of the sample prepared in Example 1 (42.0%).

[0086] Figure 9 shows a comparison of the luminescence thermal stability of the phosphors prepared in Example 1 and Comparative Example 1. It can be seen that the luminescence thermal stability of the phosphor prepared in Comparative Example 1 is significantly worse than that of the phosphor prepared in Example 1 at 100-225℃. The intensity of the phosphor prepared in Example 1 at 150℃ increased from 58.9% in Comparative Example 1 to 67.0%.

[0087] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A red nitride phosphor, characterized in that, The chemical composition is Sr2[Mg 1-x Li x Al 5-x Si x N7]:yEu 2+ Where 0.001≤x≤0.50, 0.0005≤y≤0.

20.

2. The red nitride phosphor according to claim 1, characterized in that, 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, Includes the following steps: According to the required stoichiometric ratio, nitrogen-containing Sr source, nitrogen-containing Mg source, nitrogen-containing Al source, nitrogen-containing Si source, Li source and Eu source are mixed and ground to obtain a mixture. After sintering the mixture, it is then ground and sieved to obtain red nitride phosphor.

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

5. The preparation method according to claim 3 or 4, characterized in that, The sintering pressure is 0-1.0 MPa, and the sintering atmosphere is nitrogen or a nitrogen-hydrogen mixture.

6. The preparation method according to claim 5, characterized in that, The nitrogen-hydrogen mixture 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℃, and the holding time is 2–20h.

8. The application of the red nitride phosphor according to claim 1 or 2 or the red nitride phosphor prepared by the preparation method according to any one of claims 3 to 7 in blue light-excited laser display devices.

9. The application of the red nitride phosphor according to claim 1 or 2 or the red nitride phosphor prepared by the preparation method according to any one of claims 3 to 7 in a blue light-excited liquid crystal display.

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