Ni < 2 + >-doped magnesium lanthanum aluminate-based broadband near-infrared fluorescent powder as well as preparation method and application thereof

Abstract

The invention relates to Ni < 2 + >-doped magnesium lanthanum aluminate-based broadband near-infrared fluorescent powder as well as a preparation method and application thereof, and belongs to the technical field of fluorescent materials. The chemical formula of the Ni < 2 + >-doped magnesium lanthanum aluminate-based broadband near-infrared fluorescent powder is LaMgAl11O19: xNi < 2 + >, and x is more than or equal to 0.1% and less than or equal to 2.5%. The fluorescent powder has response within the excitation range of 200-700 nm, especially can generate 900-1500 nm broadband near-infrared emission at the excitation peak of 365 nm, the center of the emission peak is located at 1175 nm, the half-peak width reaches 230 nm, efficient excitation can be achieved through purple light or blue light, the fluorescent powder has the advantages of being high in luminous intensity, large in half-peak width, adjustable in wavelength, wide in excitation range, wide in emission spectrum band and the like, and the fluorescent powder can be widely applied to the field of light emitting devices. The prepared NIR pc-LED device shows good tissue penetrability and night vision imaging performance, and is suitable for night vision observation, infrared detection and other related fields.

Description

Technical Field

[0001] This invention relates to a Ni 2+ The doped magnesium magnesium aluminate lanthanum-based broadband near-infrared phosphor, its preparation method and application, belong to the field of fluorescent materials technology. Background Technology

[0002] In recent years, near-infrared light sources have been widely used in night vision surveillance, non-radiation biomedical imaging, and other fields due to their strong penetrating power, invisibility, and unique interactions with matter. Currently, there are many commercially available near-infrared light sources, such as tungsten / halogen lamps, silicon carbide rods, near-infrared lasers, and infrared light-emitting diodes (LEDs). However, they all have corresponding drawbacks, such as high energy consumption, large size, narrow spectral band, and spectral instability. Therefore, researchers are committed to developing more efficient and energy-saving near-infrared light sources. Inspired by the packaging of white LEDs, researchers have developed near-infrared phosphor-converting light-emitting diodes (NIR pc-LEDs) that combine broadband near-infrared phosphors with mature LED chip packaging. This type of near-infrared light source has low energy consumption, small size, high radiative flux, and tunable emission with proper device design. Therefore, the development of efficient, thermally stable broadband near-infrared phosphors suitable for excitation by mature LED chips is urgently needed.

[0003] There are already many reports on this topic, such as the paper "Site Engineering Strategy toward Enhanced Luminescence Thermostability of a Cr 3+ The paper "-doped Broadband NIR Phosphor and Its Application" (Materials Chemistry Frontiers, 2021, 5(10): 3841-3849.) reports a method for adjusting SrGa 12 O 19 -LaMgGa 11 O 19 :Cr 3+ Using positional symmetry in the system to improve the luminescence and thermal stability of near-infrared phosphors is an effective strategy for preparing SrGa 12 O 19 :Cr 3+ The phosphor exhibits significant near-infrared emission at 770 nm and possesses an external quantum efficiency of 45% under 450 nm excitation. (Reference: "LaMgGa...") 11 O 19 :Cr 3+ Ni 2+The paper "Blue-light Excitable Near-infrared Luminescent Materials with Ultra-wide Emission and High External Quantum Efficiency" (Advanced Optical Materials, 2023, 11(6):2202478) reports a blue-light-excited LaMgGa 11 O 19 :Cr 3+ Ni 2+ Broadband near-infrared phosphor. This was achieved by constructing a phosphor derived from Cr... 3 + To Ni 2+ Energy transfer, LaMgGa 11 O 19 :Cr 3+ Ni 2+ The phosphors exhibit near-infrared emission in the 650–1600 nm range and significantly improve the external quantum efficiency (EQE). However, the aforementioned magnetoplumbium-structured fluorescent materials all exhibit short-wavelength near-infrared emission with narrow spectral bands. Summary of the Invention

[0004] This invention addresses the problems of relatively narrow near-infrared spectral coverage (<50nm), low output power, and high cost of existing technologies by providing a Ni 2+ Lanthanum magnesium aluminate-based broadband near-infrared phosphor, its preparation method, and its application.

[0005] The technical solution provided by this invention is as follows: One of the objectives of this invention is to provide a Ni 2+ The doped lanthanum magnesium aluminate-based broadband near-infrared phosphor has the following chemical formula: LaMgAl 11 O 19 :xNi 2+ In the formula, 0.1%≤x≤2.5%.

[0006] The effect of adopting the above technical solution: LaMgAl with magnetoplumble structure 11 O 19 The matrix exhibits high chemical, thermal, and optical stability, and its structure contains multiple octahedral crystal lattice sites. Due to the LaMgAl... 11 O 19 The crystal structure contains [Mg / AlO4] tetrahedral and [AlO6] octahedral lattice sites, Ni 2+ Belongs to 3D 8 Electronic structure, sensitive to crystal field coordination environment, Ni 2+ Occupy Al3+ Octahedral sites, Mg 2+ To balance Ni 2+ Ions and Al 3+ The charge difference between ions enables the desired broadband long-wave emission.

[0007] Furthermore, the near-infrared phosphor has an emission wavelength of 900~1500nm and a half-peak width of 200~250nm.

[0008] The second objective of this invention is to provide a Ni 2+ The preparation method of doped lanthanum magnesium aluminate-based broadband near-infrared phosphor includes the following steps: 1) Select La2O3, MgO, Al2O3, and NiO as initial raw materials, and accurately weigh the required raw materials according to the stoichiometric ratio of the chemical formula of the near-infrared phosphor; 2) Place the initial raw materials weighed in step 1) into a mortar, add anhydrous ethanol, and grind for 25-35 minutes to obtain a uniform mixture; 3) Transfer the uniform mixture obtained in step 2) into a crucible and put it into a muffle furnace. In an air atmosphere, first pre-fire at 500~600℃ for 2 hours, then sinter at 1450~1550℃ for 3~5 hours, and finally cool naturally to room temperature. 4) Take out the cooled sample from step 3), grind and sieve it to obtain Ni. 2+ Lanthanum magnesium aluminate-based broadband near-infrared phosphor.

[0009] Furthermore, in step 1), the initial raw materials are all nano-sized high-purity oxides.

[0010] Furthermore, in step 2), the amount of anhydrous ethanol added is 2-4 ml of anhydrous ethanol per gram of initial raw material.

[0011] Furthermore, in step 4), the grinding time is 5-15 minutes, and the sieving is done through a 100-300 mesh sieve.

[0012] A third objective of this invention is to provide a NIR pc-LED, comprising the Ni as described above. 2+ Lanthanum magnesium aluminate-based broadband near-infrared phosphor.

[0013] The fourth objective of this invention is to provide the application of NIR pc-LED as described above in night vision imaging and infrared detection.

[0014] The fifth objective of this invention is to provide a method for preparing a NIR pc-LED as described above, comprising the following steps: preparing Ni 2+The doped magnesium magnesium aluminate lanthanum-based broadband near-infrared phosphor is mixed with A and B adhesives at a mass ratio of 1:0.5:0.5 to obtain a powder-adhesive mixture. The powder-adhesive mixture is then dropped onto a 320~380nm violet semiconductor LED chip and dried at a temperature of 80~120℃ to obtain a NIR pc-LED.

[0015] The technical solution provided by this invention has the following advantages compared with the prior art: This invention provides a near-infrared phosphor with a magnetoplumbium structure, which has advantages such as multiple octahedral sites, wide spectral coverage, and stable performance. Its preparation method is simple and efficient, with a short reaction time, and the process is easy to operate, environmentally friendly, and highly reproducible, making it suitable for large-scale industrial production.

[0016] The near-infrared phosphor of this invention has an excitation wavelength of 200-700 nm and an emission wavelength of 900-1500 nm, with a half-width at half-maximum (WHM) of 200-250 nm. This phosphor can generate broadband near-infrared emission of 900-1500 nm at its 365 nm excitation peak, with the emission peak center located at 1175 nm and a WHM of 230 nm. The near-infrared phosphor of this invention can be efficiently excited by violet or blue light, and possesses advantages such as high luminous intensity, large WHM, tunable wavelength, wide excitation range, and wide emission spectrum.

[0017] The NIR pc-LED device prepared based on this phosphor exhibits good tissue penetration and night vision imaging performance, and is suitable for night vision observation, infrared detection and other related fields. Attached Figure Description

[0018] Figure 1 LaMgAl prepared in Examples 1-6 of this invention 11 O 19 :xNi 2+ XRD patterns and standard cards of phosphors (x = 0.1%, 0.5%, 1.0%, 1.5%, 2.0%, and 2.5%); Figure 2 LaMgAl prepared in Examples 1-6 of this invention 11 O 19 :xNi 2+ Emission spectra of phosphors (x = 0.1%, 0.5%, 1.0%, 1.5%, 2.0%, and 2.5%); Figure 3 LaMgAl prepared in Examples 1-6 of this invention 11 O 19 :xNi 2+ Intensity trend graph of phosphor (x=0.1%, 0.5%, 1.0%, 1.5%, 2.0%, and 2.5%); Figure 4 LaMgAl prepared in Example 3 of this invention 11 O 19 1.0%Ni 2+ Excitation and emission spectra of phosphors; Figure 5 LaMgAl prepared in Examples 1-6 of this invention 11 O 19 :xNi 2+ Fluorescence lifetime diagrams of phosphors at x = 0.1%, 0.5%, 1.0%, 1.5%, 2.0%, and 2.5%; Figure 6 LaMgAl prepared in Example 3 of this invention 11 O 19 1.0%Ni 2+ Electron micrograph of the phosphor; Figure 7 LaMgAl prepared in Example 3 of this invention 11 O 19 1.0%Ni 2+ Application diagram of infrared detection; Figure 8 LaMgAl prepared in Example 3 of this invention 11 O 19 1.0%Ni 2+ Application diagram of night vision imaging. Detailed Implementation

[0019] The principles and features of the present invention are described below with reference to examples. The examples are only used to explain the present invention and are not intended to limit the scope of the present invention.

[0020] The raw materials used in the examples are all nano-grade high-purity oxides.

[0021] In the examples, adhesives A and B are transparent epoxy resin potting compounds. Adhesive A is the epoxy resin matrix, and adhesive B is the curing agent. They were purchased from Delang Adhesives, model D-600AB-TM.

[0022] Example 1: In this example, Ni 2+ Lanthanum magnesium aluminate-based broadband near-infrared phosphor, with the chemical formula LaMgAl 11 O 19 0.1%Ni 2+ .

[0023] A Ni 2+ Lanthanum-doped magnesium aluminate-based broadband near-infrared phosphor LaMgAl 11 O 19 0.1%Ni 2+The preparation method and specific steps are as follows: (1) Mix the raw materials La2O3, MgO, Al2O3, and NiO according to the chemical formula LaMgAl 11 O 19 0.1%Ni 2+ The stoichiometric ratio in the sample must be accurately measured; (2) Place the weighed raw materials in an agate mortar and add 3 ml of anhydrous ethanol to each gram of raw materials. Grind carefully for 30 minutes to obtain a uniform mixture. (3) Transfer the obtained uniform mixture to a corundum crucible and put it into a muffle furnace. In an air atmosphere, first pre-fire at 550°C for 2 hours, then sinter at 1500°C for 4 hours, and finally cool naturally to room temperature. (4) Take out the cooled sample, grind it for 10 minutes, and pass it through a 200-mesh sieve to obtain Ni. 2+ Lanthanum-doped magnesium aluminate-based broadband near-infrared phosphor LaMgAl 11 O 19 0.1%Ni 2+ .

[0024] LaMgAl prepared in Example 1 11 O 19 0.1%Ni 2+ The XRD pattern of the near-infrared phosphor is as follows: Figure 1 As shown, the synthesized LaMgAl 11 O 19 0.1%Ni 2+ The diffraction peaks of the sample and LaMgAl 11 O 19 The diffraction peaks of the standard card matched well, with no extraneous peaks appearing, indicating that the synthesized LaMgAl 11 O 19 0.1%Ni 2+ Near-infrared phosphors are pure phases.

[0025] The LaMgAl 11 O 19 0.1%Ni 2+ The emission spectrum of the near-infrared phosphor is as follows: Figure 2 As shown, under 365nm ultraviolet light excitation, the main emission wavelength peak is located at 1175nm, and the full width at half maximum (FWHM) is 238nm.

[0026] The LaMgAl 11 O 19 0.1%Ni 2+ The application of near-infrared phosphors in the fabrication of NIR pc-LED devices specifically involves: using Ni... 2+ Lanthanum-doped magnesium aluminate-based broadband near-infrared phosphor LaMgAl11 O 19 0.1%Ni 2+ The powder-adhesive mixture was obtained by mixing A and B adhesives at a mass ratio of 1:0.5:0.5. Then, the powder-adhesive mixture was dropped onto a 365nm semiconductor chip and dried at 100℃ to obtain an NIR pc-LED device.

[0027] Example 2: In this example, Ni 2+ Lanthanum magnesium aluminate-based broadband near-infrared phosphor, with the chemical formula LaMgAl 11 O 19 0.5%Ni 2+ .

[0028] A Ni 2+ Lanthanum-doped magnesium aluminate-based broadband near-infrared phosphor LaMgAl 11 O 19 0.5%Ni 2+ The preparation method and specific steps are as follows: (1) Mix the raw materials La2O3, MgO, Al2O3, and NiO according to the chemical formula LaMgAl 11 O 19 0.5%Ni 2+ The stoichiometric ratios in the sample must be accurately measured.

[0029] (2) Place the weighed raw materials in an agate mortar and add 3 ml of anhydrous ethanol to each gram of raw materials. Grind carefully for 30 minutes to obtain a uniform mixture.

[0030] (3) Transfer the obtained uniform mixture to a corundum crucible and put it into a muffle furnace. In an air atmosphere, pre-fire at 550°C for 2 hours, then sinter at 1500°C for 4 hours, and finally cool naturally to room temperature.

[0031] (4) Take out the cooled sample, grind it for 10 minutes, and pass it through a 200-mesh sieve to obtain Ni. 2+ Lanthanum-doped magnesium aluminate-based broadband near-infrared phosphor LaMgAl 11 O 19 0.5%Ni 2+ .

[0032] LaMgAl prepared in Example 2 11 O 19 0.5%Ni 2+ The XRD pattern of the near-infrared phosphor is as follows: Figure 1 As shown, the synthesized LaMgAl 11 O 19 0.5%Ni 2+ The diffraction peaks of the sample and LaMgAl 11O 19 The diffraction peaks of the standard card matched well, with no extraneous peaks appearing, indicating that the synthesized LaMgAl 11 O 19 0.5%Ni 2+ Near-infrared phosphors are pure phases.

[0033] The LaMgAl 11 O 19 0.5%Ni 2+ The emission spectrum of the near-infrared phosphor is as follows: Figure 2 As shown, under 365nm ultraviolet light excitation, the main emission wavelength peak is located at 1175nm, and the full width at half maximum (FWHM) is 236nm.

[0034] The LaMgAl 11 O 19 0.5%Ni 2+ The application of near-infrared phosphors in the fabrication of NIR pc-LED devices specifically involves: using Ni... 2+ Lanthanum-doped magnesium aluminate-based broadband near-infrared phosphor LaMgAl 11 O 19 0.5%Ni 2+ The powder-adhesive mixture is thoroughly mixed with adhesives A and B at a mass ratio of 1:0.5:0.5 to obtain a powder-adhesive mixture. Then, the powder-adhesive mixture is dropped onto a 365nm semiconductor chip and dried at 100℃ to obtain an NIR pc-LED device.

[0035] Example 3: In this example, Ni 2+ Lanthanum magnesium aluminate-based broadband near-infrared phosphor, with the chemical formula LaMgAl 11 O 19 1.0%Ni 2+ .

[0036] A Ni 2+ Lanthanum-doped magnesium aluminate-based broadband near-infrared phosphor LaMgAl 11 O 19 1.0%Ni 2+ The preparation method and specific steps are as follows: (1) Mix the raw materials La2O3, MgO, Al2O3, and NiO according to the chemical formula LaMgAl 11 O 19 1.0%Ni 2+ The stoichiometric ratios in the sample must be accurately measured.

[0037] (2) Place the weighed raw materials in an agate mortar and add 3 ml of anhydrous ethanol to each gram of raw materials. Grind carefully for 30 minutes to obtain a uniform mixture.

[0038] (3) Transfer the obtained uniform mixture to a corundum crucible and put it into a muffle furnace. In an air atmosphere, pre-fire at 550°C for 2 hours, then sinter at 1500°C for 4 hours, and finally cool naturally to room temperature.

[0039] (4) Take out the cooled sample, grind it for 10 minutes, and pass it through a 200-mesh sieve to obtain Ni. 2+ Lanthanum-doped magnesium aluminate-based broadband near-infrared phosphor LaMgAl 11 O 19 1.0%Ni 2+ .

[0040] LaMgAl prepared in Example 3 11 O 19 1.0%Ni 2+ The XRD pattern of the near-infrared phosphor is as follows: Figure 1 As shown, the synthesized LaMgAl 11 O 19 1.0%Ni 2+ The diffraction peaks of the sample and LaMgAl 11 O 19 The diffraction peaks of the standard card matched well, with no extraneous peaks appearing, indicating that the synthesized LaMgAl 11 O 19 1.0%Ni 2+ Near-infrared phosphors are pure phases.

[0041] The LaMgAl 11 O 19 1.0%Ni 2+ The emission spectrum of the near-infrared phosphor is as follows: Figure 2 As shown, under 365nm ultraviolet light excitation, the main emission wavelength peak is located at 1175nm, and the full width at half maximum (FWHM) is 230nm.

[0042] LaMgAl prepared in Example 3 11 O 19 1.0%Ni 2+ Excitation and emission spectra of near-infrared phosphors are as follows: Figure 4 As shown, under 365nm ultraviolet light excitation, it exhibits an emission wavelength of 1175nm; at the emission monitoring wavelength of 1175nm, the excitation spectrum shows excitation bands at 365nm and 585nm, which is mainly attributed to... 3 A2( 3 F)→ 3 T1( 3 Spin-allowed transitions of P) and 3 A2( 3 F)→ 3 T1( 3 Spin-allowed transitions of F).

[0043] The LaMgAl 11 O 19 1.0%Ni 2+ Morphology of near-infrared phosphor as shown in the figure Figure 6 As shown, the sample exhibits a layered structure with a smooth and flat surface and a complete structure, which is conducive to enhancing fluorescence intensity.

[0044] The LaMgAl 11 O 19 1.0%Ni 2+ The application of near-infrared phosphors in the fabrication of NIR pc-LED devices specifically involves: using Ni... 2+ Lanthanum-doped magnesium aluminate-based broadband near-infrared phosphor LaMgAl 11 O 19 1.0%Ni 2+ The powder-adhesive mixture is mixed with A and B adhesives at a mass ratio of 1:0.5:0.5 to obtain a powder-adhesive mixture. Then, the powder-adhesive mixture is dropped onto a 365nm semiconductor chip and dried at 100℃ to obtain an NIR pc-LED device.

[0045] The LaMgAl 11 O 19 1.0%Ni 2+ Applications of near-infrared phosphors in infrared detection, such as Figure 7 As shown, under white light, the content of the drug in the opaque reagent bottle is not visible, in LaMgAl 11 O 19 1.0%Ni 2+ Under a NIR pc-LED lamp fabricated with near-infrared phosphor and a 365nm chip, the reagent bottle has a clear outline and the remaining amount of medicine in the bottle can be seen, demonstrating strong penetrability.

[0046] The LaMgAl 11 O 19 1.0%Ni 2+ Applications of near-infrared phosphors in night vision imaging, such as Figure 8 As shown, the left half is an orange under natural light, with its shape clearly visible; the middle half is in complete darkness, with nothing visible; the right half is under NIR pc-LED illumination, capturing the outline of the orange and demonstrating the application of packaged NIR pc-LED devices in night vision imaging.

[0047] Example 4: In this example, Ni 2+ Lanthanum magnesium aluminate-based broadband near-infrared phosphor, with the chemical formula LaMgAl 11O 19 1.5% Ni 2+ .

[0048] A Ni 2+ Lanthanum-doped magnesium aluminate-based broadband near-infrared phosphor LaMgAl 11 O 19 1.5% Ni 2+ The preparation method and specific steps are as follows: (1) Mix the raw materials La2O3, MgO, Al2O3, and NiO according to the chemical formula LaMgAl 11 O 19 1.5% Ni 2+ The stoichiometric ratios in the sample must be accurately measured.

[0049] (2) Place the weighed raw materials in an agate mortar and add 3 ml of anhydrous ethanol to each gram of raw materials. Grind carefully for 30 minutes to obtain a uniform mixture.

[0050] (3) Transfer the obtained uniform mixture to a corundum crucible and put it into a muffle furnace. In an air atmosphere, pre-fire at 550°C for 2 hours, then sinter at 1500°C for 4 hours, and finally cool naturally to room temperature.

[0051] (4) Take out the cooled sample, grind it for 10 minutes, and pass it through a 200-mesh sieve to obtain Ni. 2+ Lanthanum-doped magnesium aluminate-based broadband near-infrared phosphor LaMgAl 11 O 19 1.5% Ni 2+ .

[0052] LaMgAl prepared in Example 4 11 O 19 1.5% Ni 2+ The XRD pattern of the near-infrared phosphor is as follows: Figure 1 As shown, the synthesized LaMgAl 11 O 19 1.5% Ni 2+ The diffraction peaks of the sample and LaMgAl 11 O 19 The diffraction peaks of the standard card matched well, with no extraneous peaks appearing, indicating that the synthesized LaMgAl 11 O 19 1.5% Ni 2+ Near-infrared phosphors are pure phases.

[0053] The LaMgAl 11 O 19 1.5% Ni 2+ The emission spectrum of the near-infrared phosphor is as follows: Figure 2As shown, under 365nm ultraviolet light excitation, the main emission wavelength peak is located at 1175nm, and the full width at half maximum (FWHM) is 237nm.

[0054] The LaMgAl 11 O 19 1.5% Ni 2+ The application of near-infrared phosphors in the fabrication of NIR pc-LED devices specifically involves: using Ni... 2+ Lanthanum-doped magnesium aluminate-based broadband near-infrared phosphor LaMgAl 11 O 19 1.5% Ni 2+ The powder-adhesive mixture is mixed with A and B adhesives at a mass ratio of 1:0.5:0.5 to obtain a powder-adhesive mixture. Then, the powder-adhesive mixture is dropped onto a 365nm semiconductor chip and dried at 100℃ to obtain an NIR pc-LED device.

[0055] Example 5: This example Ni 2+ Lanthanum magnesium aluminate-based broadband near-infrared phosphor, with the chemical formula LaMgAl 11 O 19 2.0%Ni 2+ .

[0056] A Ni 2+ Lanthanum-doped magnesium aluminate-based broadband near-infrared phosphor LaMgAl 11 O 19 2.0%Ni 2+ The preparation method and specific steps are as follows: (1) Mix the raw materials La2O3, MgO, Al2O3, and NiO according to the chemical formula LaMgAl 11 O 19 2.0%Ni 2+ The stoichiometric ratios in the sample must be accurately measured.

[0057] (2) Place the weighed raw materials in an agate mortar and add 3 ml of anhydrous ethanol to each gram of raw materials. Grind carefully for 30 minutes to obtain a uniform mixture.

[0058] (3) Transfer the obtained uniform mixture to a corundum crucible and put it into a muffle furnace. In an air atmosphere, pre-fire at 550°C for 2 hours, then sinter at 1500°C for 4 hours, and finally cool naturally to room temperature.

[0059] (4) Take out the cooled sample, grind it for 10 minutes, and pass it through a 200-mesh sieve to obtain Ni. 2+ Lanthanum-doped magnesium aluminate-based broadband near-infrared phosphor LaMgAl 11 O 19 2.0%Ni 2+ .

[0060] LaMgAl prepared in Example 5 11 O 19 2.0%Ni 2+ The XRD pattern of the near-infrared phosphor is as follows: Figure 1 As shown, the synthesized LaMgAl 11 O 19 2.0%Ni 2+ The diffraction peaks of the sample and LaMgAl 11 O 19 The diffraction peaks of the standard card matched well, with no extraneous peaks appearing, indicating that the synthesized LaMgAl 11 O 19 2.0%Ni 2+ Near-infrared phosphors are pure phases.

[0061] The LaMgAl 11 O 19 2.0%Ni 2+ The emission spectrum of the near-infrared phosphor is as follows: Figure 2 As shown, under 365nm ultraviolet light excitation, the main emission wavelength peak is located at 1175nm, and the full width at half maximum (FWHM) is 239nm.

[0062] The LaMgAl 11 O 19 2.0%Ni 2+ The application of near-infrared phosphors in the fabrication of NIR pc-LED devices specifically involves: using Ni... 2+ Lanthanum-doped magnesium aluminate-based broadband near-infrared phosphor LaMgAl 11 O 19 2.0%Ni 2+ The powder-adhesive mixture is mixed with A and B adhesives at a mass ratio of 1:0.5:0.5 to obtain a powder-adhesive mixture. Then, the powder-adhesive mixture is dropped onto a 365nm semiconductor chip and dried at 100℃ to obtain an NIR pc-LED device.

[0063] Example 6: This example Ni 2+ Lanthanum magnesium aluminate-based broadband near-infrared phosphor, with the chemical formula LaMgAl 11 O 19 2.5%Ni 2+ .

[0064] A Ni 2+ Lanthanum-doped magnesium aluminate-based broadband near-infrared phosphor LaMgAl 11 O 19 2.5%Ni 2+ The preparation method and specific steps are as follows: (1) Mix the raw materials La2O3, MgO, Al2O3, and NiO according to the chemical formula LaMgAl 11 O 19 2.5%Ni 2+ The stoichiometric ratios in the sample must be accurately measured.

[0065] (2) Place the weighed raw materials in an agate mortar and add 3 ml of anhydrous ethanol to each gram of raw materials. Grind carefully for 30 minutes to obtain a uniform mixture.

[0066] (3) Transfer the obtained uniform mixture to a corundum crucible and put it into a muffle furnace. In an air atmosphere, pre-fire at 550°C for 2 hours, then sinter at 1500°C for 4 hours, and finally cool naturally to room temperature.

[0067] (4) Take out the cooled sample, grind it for 10 minutes, and pass it through a 200-mesh sieve to obtain Ni. 2+ Lanthanum-doped magnesium aluminate-based broadband near-infrared phosphor LaMgAl 11 O 19 2.5%Ni 2+ .

[0068] LaMgAl prepared in Example 6 11 O 19 2.5%Ni 2+ The XRD pattern of the near-infrared phosphor is as follows: Figure 1 As shown, the synthesized LaMgAl 11 O 19 2.5%Ni 2+ The diffraction peaks of the sample and LaMgAl 11 O 19 The diffraction peaks of the standard card matched well, with no extraneous peaks appearing, indicating that the synthesized LaMgAl 11 O 19 2.5%Ni 2+ Near-infrared phosphors are pure phases.

[0069] The LaMgAl 11 O 19 2.5%Ni 2+ The emission spectrum of the near-infrared phosphor is as follows: Figure 2 As shown, under 365nm ultraviolet light excitation, the main emission wavelength peak is located at 1175nm, and the full width at half maximum (FWHM) is 241nm.

[0070] The LaMgAl 11 O 19 2.5%Ni 2+ The application of near-infrared phosphors in the fabrication of NIR pc-LED devices specifically involves: using Ni... 2+Lanthanum-doped magnesium aluminate-based broadband near-infrared phosphor LaMgAl 11 O 19 2.5%Ni 2+ The powder-adhesive mixture is mixed with A and B adhesives at a mass ratio of 1:0.5:0.5 to obtain a powder-adhesive mixture. Then, the powder-adhesive mixture is dropped onto a 365nm semiconductor chip and dried at 100℃ to obtain an NIR pc-LED device.

[0071] The phosphor LaMgAl of the present invention 11 O 19 :xNi 2+ The fluorescence intensity trends for (x = 0.1%, 0.5%, 1.0%, 1.5%, 2.0%, and 2.5%) are as follows: Figure 3 As shown, with Ni 2+ With increasing doping concentration, the luminescence intensity of Examples 1-6 showed a trend of first increasing and then decreasing. In the LaMgAl prepared in this invention... 11 O 19 :xNi 2+ Among six near-infrared phosphors (x = 0.1%, 0.5%, 1.0%, 1.5%, 2.0%, and 2.5%), the LaMgAl prepared in Example 3... 11 O 19 1.0%Ni 2+ Near-infrared phosphors exhibit the strongest fluorescence intensity.

[0072] The LaMgAl 11 O 19 :xNi 2+ The fluorescence lifetime of near-infrared phosphors is as follows Figure 5 As shown, with Ni 2+ With increasing doping concentration, the LaMgAl prepared in this invention... 11 O 19 :xNi 2+ The lifetime of the near-infrared phosphor (x = 0.1%, 0.5%, 1.0%, 1.5%, 2.0%, and 2.5%) showed a monotonically decreasing trend, decaying from 0.335 ms to 0.191 ms. The LaMgAl prepared in Example 3... 11 O 19 1.0%Ni 2+ The near-infrared phosphor has a fluorescence lifetime of 0.256 ms, which is due to the higher Ni content. 2+ This is due to the increased probability of nonradiative transitions at higher concentrations.

[0073] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A Ni 2+ The doped magnesium lanthanum aluminate-based broadband near-infrared fluorescent powder is characterized by comprising: The chemical formula is as follows: LaMgAl 11 O 19 :xNi 2+ , wherein 0.1%≤x≤2.5%.

2. The Ni of claim 1 2+ The doped magnesium lanthanum aluminate-based broadband near-infrared fluorescent powder is characterized in that, The emission wavelength of the near-infrared fluorescent powder is 900-1500 nm, and the emission peak half-peak width is 200-250 nm.

3. A Ni as claimed in claim 1 or 2 2+ The preparation method of the doped magnesium lanthanum aluminate-based broadband near-infrared fluorescent powder is characterized by comprising the following steps: The method comprises the following steps: 1) selecting La2O3, MgO, Al2O3 and NiO as initial raw materials, and accurately weighing the required initial raw materials according to the stoichiometric ratio of the chemical formula of the near-infrared fluorescent powder; 2) placing the initial raw materials weighed in step 1) in a mortar, adding anhydrous ethanol, and grinding for 25-35 min to obtain a uniform mixture; 3) transferring the uniform mixture obtained in step 2) into a crucible, and sending it into a muffle furnace, first pre-sintering at 500-600 ℃ for 2 h in an air atmosphere, then sintering at 1450-1550 ℃ for 3-5 h, and finally naturally cooling to room temperature; 4) The sample after cooling in step 3) is taken out, ground and sieved, and Ni 2+ Doped magnesium lanthanum aluminate-based broadband near-infrared fluorescent powder.

4. The Ni of claim 3 2+ The preparation method of the doped magnesium lanthanum aluminate-based broadband near-infrared fluorescent powder is characterized by comprising the following steps: In step 1), the initial raw materials are all nanoscale high-purity oxides.

5. The Ni of claim 3 2+ The preparation method of the doped magnesium lanthanum aluminate-based broadband near-infrared fluorescent powder is characterized by comprising the following steps: In step 2), the amount of anhydrous ethanol added is 2-4 ml per gram of initial raw material.

6. The Ni of claim 3 2+ The preparation method of the doped magnesium lanthanum aluminate-based broadband near-infrared fluorescent powder is characterized by comprising the following steps: In step 4), the grinding time is 5-15 min, and the sieving is through a 100-300 mesh sieve.

7. A NIR pc-LED, characterized in that, Ni comprising the Ni of claim 1 or 2 2+ Doped magnesium lanthanum aluminate-based broadband near-infrared fluorescent powder.

8. Application of the NIR pc-LED according to claim 7 in night vision imaging and infrared detection.

9. The method of making a NIR pc-LED according to claim 7, wherein, comprising the steps of: providing a Ni 2+ The doped magnesium lanthanum aluminate-based broadband near-infrared fluorescent powder is mixed with A and B glue according to a mass ratio of 1:0.5:0.5 to obtain a powder-glue mixture, then the powder-glue mixture slurry is dropped on a 320-380 nm ultraviolet semiconductor LED chip, and dried at a temperature of 80-120 ℃, to obtain a NIR pc-LED.

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