Near-infrared fluorescent powder based on energy resonance transfer effect, preparation process and application thereof

Abstract

This invention discloses a near-infrared phosphor based on the energy resonance transfer effect, its preparation process, and its application, belonging to the technical field of LED phosphors. The chemical formula of the near-infrared phosphor based on the energy resonance transfer effect is: Zn 1‑a Ca a Ga 2‑2a‑x‑ y In 2a O4: xNi / yCe, where 0.01≤a≤0.09, x=0.008, 0.002≤y≤0.008; its preparation method includes eight steps: weighing, wet ball milling, vacuum drying, grinding with additives, pre-calcination, re-grinding, high-temperature calcination, and graded grinding. This invention utilizes Ca... 2+ / In 3+ Co-doping regulates charge balance, Ce 4+ By introducing defect energy levels, a triple synergistic system of "lattice structure-energy level matching-defect modulation" was constructed, achieving energy resonance transfer with an internal quantum efficiency greater than 45% and excellent thermal stability. Near-infrared LED devices encapsulated with modified silicone adhesive exhibit high output power and minimal aging transmittance degradation, making them widely applicable in night vision surveillance, medical, and spectral detection fields.

Description

Technical Field

[0001] This invention belongs to the field of LED phosphor technology, and relates to a near-infrared phosphor based on energy resonance transfer effect, its preparation process and application. Background Technology

[0002] In the field of modern photonics, core applications such as solid-state lighting, biomedical imaging, and near-infrared (NIR) detection, especially the development of near-infrared II (NIR-II) luminescent materials, have become a research hotspot in bioimaging and high-end detection. However, existing materials generally suffer from low external quantum efficiency and slow response speed, necessitating the development of novel control strategies to overcome these bottlenecks. ZnGa2O4 spinel-type luminescent materials, with their wide bandgap, stable crystal structure, and flexible tunable luminescence properties, provide an attractive platform for studying the local structure around the luminescence center and improving the luminescence response. This can be achieved by doping with Dy... 3+ Mn 2+ and Cr 3+ High-resolution and fast-response phosphors for white, green, and red light can be obtained, or nanocomposite materials can be made to meet medical imaging and harmless applications. 2+ Ions are characterized by their unique electronic configuration (3d... 8 It exhibits strong dd transition characteristics in an octahedral field. When excited by ultraviolet light, it undergoes... 3 T2( 3 F)→ 3 A2( 3 The characteristic transition of F) is compared to other Nd2 atoms that can emit light in NIR-II or NIR-III. 3+ Ho 3+ Er 3+ Tm 3+ Yb 3+ Plasma, due to 4f-4f spin parity forbidding, exhibits narrow-band near-infrared emission characteristics, Ni 2+ It can produce broadband spectra covering NIR-II and NIR-III, making it more suitable as a detection light source. (The text abruptly shifts to a seemingly unrelated topic about transition metal ions and Cr.) 4+ Mn 5+ In comparison, Cr 4+ and Mn 5+ The choice of substrate is more stringent. And Ni 2+ Its ability to be excited by ultraviolet / blue light InGaN chips has garnered widespread attention. Currently, Huang et al. have prepared Sr2ScTaO6:0.03Ni... 2+Achieving ultrawide emission in the 1100-1700 nm range with a full width at half maximum (FWHM) of 254 nm and internal quantum yield (IQY) and external quantum yield (EQY) of 49.23% and 22.41% respectively, significantly improves Ni... 2+ Energy utilization efficiency and application range of doped phosphors; Li + / Ga 3+ Co-doping tunable ZnGa2O4:Cr 3+ The trap distribution enhances near-infrared long afterglow performance; the introduction of the energy transfer mechanism provides a new path for efficient luminescence, Ce 4+ As an excellent sensitizer, it can significantly enhance the luminescence intensity of the activator through energy transfer, but existing regulation strategies have not yet formed a triple synergistic system of "lattice structure-energy level matching-defect regulation". Summary of the Invention

[0003] To address the problems existing in the background technology, the present invention provides a near-infrared phosphor based on the energy resonance transfer effect, its preparation process, and its application.

[0004] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0005] A method for preparing near-infrared phosphor based on energy resonance transfer effect includes the following steps:

[0006] Step 1: According to the general chemical formula Zn 1-a Ca a Ga 2-2a-x-y In 2a O4: The stoichiometric ratio of xNi / yCe is used to weigh Zn source, Ca source, Ga source, In source, Ni source and Ce source as raw materials;

[0007] Step 2: Mix the raw materials weighed in Step 1 for the first time and place them in a planetary ball mill. Add anhydrous ethanol as the grinding medium and wet ball mill at a speed of 300-400 r / min for 2-4 hours to obtain a slurry.

[0008] Step 3: Place the slurry obtained in Step 2 in a vacuum drying oven at 80-100℃ and dry it for 10-14 hours to obtain a dried powder;

[0009] Step 4: Place the dried powder obtained in Step 3 into an agate mortar, add 0.5-1.5% of the total powder mass of the additive, and grind and mix again for 20-40 minutes to obtain the mixed precursor;

[0010] Step 5: Transfer the mixed precursor obtained in Step 4 to a crucible, place it in a tube furnace, and heat it to 400-600℃ in air atmosphere at a heating rate of 2-5℃ / min. Pre-calcine for 2-4 hours, then allow it to cool naturally to room temperature and remove the intermediate product.

[0011] Step 6: Grind the intermediate product obtained in Step 5 again for 15-25 minutes and put it back into the crucible;

[0012] Step 7: Place the crucible from Step 6 in a tube furnace and heat it to 1150-1250℃ in air at a heating rate of 3-7℃ / min. Calcine for 4-6 hours, then cool it to room temperature with the furnace to obtain the calcined product.

[0013] Step 8: The calcined product obtained in Step 7 is subjected to graded grinding. First, coarse grinding for 5-10 minutes, then fine grinding for 15-25 minutes, and then passing through a 200-400 mesh sieve to obtain near-infrared phosphor based on the energy resonance transfer effect.

[0014] Further, in step 1, the Zn source is ZnO, the Ca source is CaCO3, the Ga source is Ga2O3, the In source is In2O3, the Ni source is NiO, and the Ce source is CeO2.

[0015] Furthermore, the auxiliary agent mentioned in step 4 is NH4Cl or H3BO3.

[0016] Furthermore, in step 7, the calcination temperature is 1200℃ and the time is 5 hours.

[0017] This invention also provides a near-infrared phosphor based on the energy resonance transfer effect, wherein the chemical formula of the near-infrared phosphor is: Zn 1-a Ca a Ga 2-2a-x-y In 2a O4: xNi / yCe, where 0.001≤a≤0.09, x=0.008, 0.002≤y≤0.008.

[0018] Furthermore, the near-infrared phosphor corresponds to a matrix with a cubic crystal system and a space group of Fd. m; the excitation wavelength range is 380-650nm, the emission wavelength range is 1100-1650nm, and the internal quantum efficiency is greater than 45%.

[0019] The present invention also provides a near-infrared LED light-emitting device, comprising a packaging substrate, an LED chip and near-infrared phosphor disposed on the surface of the LED chip, wherein the LED chip is disposed on the packaging substrate and the LED chip is a violet LED chip.

[0020] Furthermore, the near-infrared phosphor and the modified silicone adhesive are mixed at a mass ratio of 1:2-2.5 and then coated on the surface of the LED chip. The modified silicone adhesive is a compound of methyl phenyl vinyl silicone resin and hydrogen-containing silicone oil at a mass ratio of 10:1. During the compounding process, the total mass of the compounding system is used as the calculation basis, and the amount of platinum catalyst added is 0.2wt%.

[0021] Furthermore, the purple LED chip is an InGaN semiconductor chip.

[0022] Furthermore, the thickness of the near-infrared phosphor coating on the LED chip surface is 100-300 μm.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] 1. The near-infrared phosphor provided by this invention exhibits high luminescence intensity and excellent temperature quenching characteristics, with an excitation band covering 380-650 nm and an emission band covering 1100-1650 nm. Compared to undoped Ce... 4+ In this system, the internal quantum yield increased from 18.25% to 46.69%, and the external quantum yield increased from 7.01% to 8.94%. This is comparable to previously reported ZnGa2O4:Ni... 2+ Compared to the previous system, this invention utilizes Ce 4+ The introduced energy resonant transfer pathway increases the absolute value of the internal quantum efficiency by 28.44 percentage points, representing a relative increase of 155.8%, which is one of the highest values ​​known among ZnGa2O4-based near-infrared phosphors. Furthermore, the phosphor of this invention maintains over 85% of its room-temperature emission intensity even at 100°C, demonstrating significantly better thermal stability than similar materials (which typically retain only 60-70%).

[0025] 2. This invention is the first to utilize ZnGa2O4:Ni 2+ A synergistic system of "lattice structure-energy level matching-defect modulation" was constructed in the system, through Ce 4+ Introducing defect energy levels, Ca 2+ / In 3+ By balancing the charge and modulating the crystal field, the energy resonant transfer path was optimized. This mechanism differs from existing single-sensitization strategies, instead employing a synergistic effect from three dimensions: crystal field theory, defect chemistry, and bandgap engineering, providing a novel theoretical paradigm for near-infrared phosphor design. EPR and transient fluorescence spectroscopy measurements confirm that Ce... 4+ The introduction of Ni 2+ The fluorescence lifetime was significantly extended, further confirming the effectiveness of resonant energy transfer.

[0026] 3. The modified silicone adhesive of this invention (methylphenyl vinyl silicone resin / hydrogen-containing silicone oil / platinum catalyst system) achieves high refractive index matching and excellent heat aging resistance. This adhesive also exhibits good airtightness and UV resistance, significantly improving the long-term operational stability of LED devices.

[0027] 4. The light-emitting device of this invention is small in size (can be integrated into a <3mm×3mm package), low in cost (the raw materials are all inexpensive metal oxides, no precious metals are required), and pollution-free (no toxic waste gas or wastewater is discharged during the manufacturing process). It can be widely used in night vision monitoring (replacing traditional infrared LEDs, increasing the supplementary lighting distance by 30%), medical imaging (visualizing blood vessels up to 5mm of subcutaneous tissue), spectral detection (for non-destructive detection of fruit sugar content and moisture), food quality monitoring (detecting internal damage), and other fields. It avoids the disadvantages of traditional infrared light sources (such as halogen tungsten lamps) such as large size (usually >50mm×50mm), high energy consumption (power >10W), and short lifespan (<2000h). At the same time, compared with existing commercial near-infrared phosphors (such as CaMgSi2O6:Cr), it also achieves significant improvements. 4+ The product of this invention has a wider spectral coverage in the 1100-1650nm range, making it more suitable for simultaneous detection of multiple components.

[0028] 5. The preparation method of this invention employs a high-temperature solid-state method, using common oxides or carbonates as raw materials. No organic solvents or strong acids / bases are required. NH4Cl can be used as an auxiliary agent during the preparation process, as it completely decomposes into a gas at high temperatures, escaping without introducing additional impurities. Through optimization of eight key process parameters (ball milling time, pre-calcination temperature and time, high-temperature calcination temperature and time, auxiliary agent dosage, heating rate, and staged grinding time), the optimal process window was obtained, and the optimal range and values ​​for each parameter are provided, facilitating quality control in industrial production. Experimental verification shows that the performance deviation between batches of phosphor prepared under optimal conditions is <3%, exhibiting good repeatability and stability.

[0029] 6. The phosphor prepared by this invention has an emission spectrum covering the 1100-1650nm infrared band, which can be widely used in many scenarios such as night vision monitoring, medical diagnosis and treatment, and spectral detection. Compared with traditional infrared light acquisition schemes, this scheme effectively avoids various inherent defects; the matching light-emitting device has the advantages of excellent luminous efficiency, small size, and low production cost, and is compatible with various equipment. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the ion-substituted structure of the matrix and modified phosphor corresponding to the embodiments of the present invention; wherein, Figure 1 a is a schematic diagram of the ion substitution structure of the ZnCaInGaO matrix material. Figure 1b is a schematic diagram of the ion substitution structure of Ni / Ce co-doped modified ZnCaInGaO phosphor (ZnCaInGaO:Ni / Ce).

[0031] Figure 2 This document presents the X-ray diffraction (XRD) spectra of samples with different doping concentrations and the refined XRD spectra of the sample with the optimal doping concentration. Figure 2 a shows the XRD patterns of ZGN:Cl phosphors with different Cl doping concentrations. Figure 2 b shows the XRD patterns of ZGCI:Ni / Ce phosphors with different Ni / Ce co-doping concentrations. Figure 2 c represents the refined XRD pattern of the ZGN:Cl phosphor at the optimal Cl doping concentration. Figure 2 d represents the refined XRD pattern of the ZGCI:Ni / Ce phosphor at the optimal Ni / Ce co-doping concentration.

[0032] Figure 3 These are the emission spectra of samples with different doping concentrations according to the present invention; wherein, Figure 3 a represents the luminescence spectra of ZGN:Cl phosphors with different Cl doping concentrations. Figure 3 b shows the luminescence spectra of ZGCI:Ni / Ce phosphors with different Ni / Ce co-doping concentrations.

[0033] Figure 4 The images show a comparison of fluorescence kinetics and electron paramagnetic resonance spectra of the sample with the optimal doping concentration according to this invention; wherein... Figure 4 a is a comparison of the time-resolved fluorescence spectra of ZGN:Cl phosphor and ZGCI:Ni / Ce phosphor at the optimal doping concentration. Figure 4 b is a comparison of electron paramagnetic resonance (EPR) data of ZGN:Cl phosphor and ZGCI:Ni / Ce phosphor at the optimal doping concentration.

[0034] Figure 5 This is a comparison of the luminescence intensity of single-doped and co-doped samples with the optimal doping concentration of this invention; wherein, Figure 5 a represents the luminescence intensity spectrum of the ZGCI:Ni single-doped phosphor at the optimal doping concentration. Figure 5 b is the luminescence intensity spectrum of the ZGCI:Ni / Ce co-doped phosphor at the optimal doping concentration.

[0035] Figure 6 X-ray photoelectron spectroscopy (XPS) measurements and peak fitting spectra of a series of samples with the optimal doping concentration for this invention; wherein, Figure 6 a is the full-spectrum XPS data of the ZGCI:Ni / Ce phosphor at the optimal doping concentration. Figure 6 b is the peak fitting diagram of the O1s characteristic peak of ZGO:Cl phosphor. Figure 6c is the peak fitting spectrum of the O1s characteristic peak of ZGN:Ce phosphor. Figure 6 d is the peak fitting diagram of the O1s characteristic peak of ZGCI:Ni / Ce phosphor.

[0036] Figure 7 The temperature-dependent fluorescence properties and activation energy fitting test spectra of the sample with the optimal doping concentration of this invention are shown; wherein, Figure 7 Figure a shows the temperature-varying fluorescence spectra of ZGN:Cl phosphor and ZGCI:Ni / Ce phosphor at the optimal doping concentration, as well as a comparison of the luminescence intensity of the two samples under different temperature conditions. Figure 7 b is the fitted spectrum of the calculated thermal activation energy of ZGN:Cl phosphor and ZGCI:Ni / Ce phosphor at the optimal doping concentration.

[0037] Figure 8 This is a schematic diagram illustrating the material properties and luminescence mechanism of the phosphor of the present invention; wherein, Figure 8 a is the Tanabe-Sugano energy level diagram constructed based on the sample composition. Figure 8 b is a schematic diagram of the near-infrared luminescence mechanism of ZGCI:Ni / Ce co-doped phosphor.

[0038] Figure 9 These are real-world test comparison images of the phosphor prepared in this invention applied to near-infrared imaging; wherein, Figure 9 a is a photograph of a fruit taken under visible light. Figure 9 b is a photograph of the hand taken under visible light. Figure 9 c is an image of fruit taken with a near-infrared camera using the phosphor prepared in this invention as the light source. Figure 9 Image d is a near-infrared image of a hand taken with the phosphor prepared in this invention as the light source and a near-infrared camera.

[0039] Figure 10 The photoelectric performance spectra of the fluorescent device prepared from the sample with the optimal doping concentration of this invention are shown; wherein, Figure 10 a is a graph showing the change in luminescence intensity of the fluorescent device under different driving current conditions. Figure 10 b is a graph showing the changes in luminous conversion efficiency and output power of the fluorescent device under different driving current conditions. Detailed Implementation

[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] In this embodiment of the invention, the preparation method of near-infrared phosphor based on energy resonance transfer effect includes the following steps:

[0042] Step 1: According to the general chemical formula Zn 1-a Ca a Ga 2-2a-x-y In 2a O4:xNi / yCe, is a chemical elemental stoichiometry method that weighs Zn source, Ca source, Ga source, In source, Ni source and Ce source as raw materials;

[0043] Step 2: Mix the raw materials weighed in Step 1 for the first time and place them in a planetary ball mill. Add anhydrous ethanol as the grinding medium and wet ball mill at a speed of 300-400 r / min for 2-4 hours to obtain a slurry.

[0044] Step 3: Place the slurry obtained in Step 2 in a vacuum drying oven at 80-100℃ and dry it for 10-14 hours to obtain a dried powder;

[0045] Step 4: Place the dried powder obtained in Step 3 into an agate mortar, add 0.5-1.5% of the total powder mass of the additive, and grind and mix again for 20-40 minutes to obtain the mixed precursor;

[0046] Step 5: Transfer the mixed precursor obtained in Step 4 to a corundum crucible, place it in a high-temperature tube furnace, and heat it to 400-600℃ in air atmosphere at a heating rate of 2-5℃ / min. Pre-calcine for 2-4 hours, then allow it to cool naturally to room temperature and remove the intermediate product.

[0047] Step 6: Grind the intermediate product obtained in Step 5 again for 15-25 minutes and put it back into the corundum crucible;

[0048] Step 7: Place the corundum crucible from Step 6 into a tube furnace and heat it to 1000-1300℃ in air at a heating rate of 3-6℃ / min. Calcinate at high temperature for 2-6 hours, and then cool it to room temperature with the furnace to obtain the calcined product.

[0049] Step 8: The calcined product obtained in Step 7 is subjected to graded grinding. First, it is coarsely ground for 5-10 minutes, then finely ground for 15-25 minutes, and passed through a 200-400 mesh sieve to obtain the near-infrared phosphor based on the energy resonance transfer effect. The chemical formula of the near-infrared phosphor is: Zn 1-a Ca a Ga 2-2a-x-y In 2a O4: xNi / yCe, where 0.01≤a≤0.09, x=0.008, 0.002≤y≤0.008.

[0050] In step 1, the Zn source is ZnO, the Ca source is CaCO3, the Ga source is Ga2O3, the In source is In2O3, the Ni source is NiO, and the Ce source is CeO2; the auxiliary agent is NH4Cl or H3BO3. In step 2, the wet ball milling speed is 350 r / min and the time is 3 h. In step 7, the high-temperature calcination temperature is 1200-1250℃ and the time is 4-5 h.

[0051] The near-infrared LED light-emitting device of the present invention includes a packaging substrate, an LED chip and a near-infrared phosphor disposed on the surface of the LED chip, wherein the LED chip is disposed on the packaging substrate and the LED chip is a violet LED chip.

[0052] In the near-infrared LED light-emitting device, near-infrared phosphor and modified silicone adhesive are mixed at a mass ratio of 1:2-2.5 and then coated onto the surface of the LED chip. The modified silicone adhesive is a mixture of methylphenyl vinyl silicone resin and hydrogen-containing silicone oil at a mass ratio of 10:1. During the mixing process, the total mass of the mixed system is used as the calculation basis, and the amount of platinum catalyst added is 0.2wt%. The violet LED chip is an InGaN semiconductor chip, and the coating thickness of the near-infrared phosphor on the surface of the LED chip is 100-300μm.

[0053] Technical principle of the invention:

[0054] This invention, based on the energy resonance transfer effect, achieves a significant improvement in the luminescence performance of materials through a cation-mediated valence state / field intensity synergistic modulation strategy. Its core principle is as follows:

[0055] 1. Defect level engineering. This invention utilizes co-doping of Ce... 4+ The ions introduce new defect levels (ET) between the valence and conduction bands of the ZnGa2O4 matrix. When Ni... 2+ Ions under 380nm violet light excitation from the ground state 3 A2( 3 F) Transitions to the excited state 3 T1( 3 After P), some electrons relax to nonradiative states. 3 T2( 3 F) energy level. However, the traditional ZnGa2O4:Ni 2+ The material contains a large number of oxygen vacancies, which can trap photogenerated carriers, leading to increased nonradiative recombination and decreased luminescence efficiency. This invention introduces Ce... 4+ Defect level ET and Ni 2+ of 3 T2( 3 F) When energy levels are close (energy level difference < 0.15 eV), electrons trapped by oxygen vacancies can transfer to the ET level via resonant tunneling or thermal excitation, and then migrate back to the Ni level.2+ of 3 T2( 3 The F) energy level eventually transitions to... 3 A2( 3 F) Near-infrared radiation is generated. This "capture-transfer-return" resonant energy transfer path effectively compensates for the number of photons lost in non-radiative transitions.

[0056] 2. Charge balance regulation. In spinel structures, Ni 2+ Ion-substituted Ga 3+ The ionic lattice sites introduce a charge imbalance (NiGa× carries an effective negative charge). To maintain electroneutrality, a large number of positively charged oxygen vacancies (V0) are spontaneously generated within the material. O •• This invention utilizes co-doped Ca. 2+ and In 3+ Ion: Ca 2+ Prioritize occupying Zn 2+ Grid position, In 3+ Occupy Ga 3+ The synergistic doping of lattice sites and both modulates local lattice strain and charge distribution. Specifically, In 3+ The introduction of Ni supplements 2+ Replace Ga 3+ The resulting loss of positive charge significantly suppresses the formation of oxygen vacancies. Electron paramagnetic resonance (EPR) tests confirmed that the oxygen vacancy signal intensity in the co-doped system of this invention is reduced by approximately 62% compared to the undoped system.

[0057] 3. Crystal field engineering. Based on the Tanabe-Sugano diagram, Ni... 2+ The luminescence properties in an octahedral coordination field are strongly dependent on the crystal field strength (Dq). This invention utilizes Ca... 2+ In 3+ Co-doping slightly lengthened the Ni-O bond length, adjusting the crystal field parameter Dq to its optimal value (approximately 780 cm⁻¹). -1 ), making 3 T2( 3 F) Energy levels and 3 A2( 3 F) The energy level difference between energy levels and non-radiative relaxation reach an optimal balance, further increasing the probability of radiative transition.

[0058] In summary, this invention constructs a triple synergistic system of "lattice structure-energy level matching-defect modulation", which achieves a significant leap in near-infrared luminescence performance.

[0059] To make the present invention more fully disclosed, more specific embodiments are described below.

[0060] Example 1

[0061] A near-infrared phosphor based on the energy resonance transfer effect, with a ZnGa2O4 matrix and Ca dopant ions. 2+ and In 3+ The doping concentration of all Ni is 3 mol%. 2+ and Ce 4+ The doping amounts are 0.8 mol% and 0.4 mol% respectively (i.e., a=0.03, x=0.008, y=0.004).

[0062] The preparation method of the near-infrared phosphor based on the energy resonance transfer effect is as follows:

[0063] Step 1: Weigh out zinc oxide (ZnO), nickel oxide (NiO), indium oxide (In2O3), calcium carbonate (CaCO3), and gallium oxide (Ga2O3) according to the stoichiometric ratio of each component element.

[0064] Step 2: Mix the raw materials weighed in Step 1 for the first time and place them in a planetary ball mill. Add 50 mL of anhydrous ethanol as the grinding medium and wet ball mill at 350 r / min for 3 h to obtain a slurry.

[0065] Step 3: Place the slurry obtained in Step 2 in a vacuum drying oven at 90℃ and dry it for 12 hours to obtain dried powder.

[0066] Step 4: Place the dried powder obtained in Step 3 into an agate mortar, add NH4Cl additive accounting for 1.0% of the total mass of the powder, and grind and mix again for 30 minutes to obtain the mixed precursor.

[0067] Step 5: Transfer the mixed precursor obtained in Step 4 to a corundum crucible, place it in a high-temperature tube furnace, and heat it to 500°C at a heating rate of 3°C / min in air atmosphere. Pre-calcine for 3 hours, then allow it to cool naturally to room temperature and remove the intermediate product.

[0068] Step 6: Grind the intermediate product obtained in Step 5 again for 20 minutes and put it back into the corundum crucible.

[0069] Step 7: Place the corundum crucible from Step 6 into a tube furnace and heat it to 1200°C at a heating rate of 5°C / min in air atmosphere. Calcinate at high temperature for 5 hours, and then cool it to room temperature with the furnace to obtain the calcined product.

[0070] Step 8: The calcined product obtained in Step 7 is subjected to graded grinding: first coarse grinding for 8 minutes, then fine grinding for 20 minutes, and then passing through a 300-mesh sieve to obtain near-infrared phosphor based on the energy resonance transfer effect.

[0071] Example 2

[0072] A near-infrared phosphor based on the energy resonance transfer effect, with a ZnGa2O4 matrix and Ca dopant ions. 2+ and In 3+ The doping concentration of all Ni is 3 mol%. 2+ The doping concentration is 0.8 mol%, Ce 4+ The doping amount is 0.2 mol% (i.e., a=0.03, x=0.008, y=0.002).

[0073] The preparation method of the near-infrared phosphor based on the energy resonance transfer effect is as follows:

[0074] Step 1: Weigh out zinc oxide (ZnO), nickel oxide (NiO), indium oxide (In2O3), calcium carbonate (CaCO3), and gallium oxide (Ga2O3) according to the stoichiometric ratio of each component element.

[0075] Step 2: Mix the raw materials weighed in Step 1 for the first time and place them in a planetary ball mill. Add 50 mL of anhydrous ethanol as the grinding medium and wet ball mill at 350 r / min for 3 h to obtain a slurry.

[0076] Step 3: Place the slurry obtained in Step 2 in a vacuum drying oven at 90℃ and dry it for 12 hours to obtain dried powder.

[0077] Step 4: Place the dried powder obtained in Step 3 into an agate mortar, add NH4Cl additive accounting for 1.0% of the total mass of the powder, and grind and mix again for 30 minutes to obtain the mixed precursor.

[0078] Step 5: Transfer the mixed precursor obtained in Step 4 to a corundum crucible, place it in a high-temperature tube furnace, and heat it to 500°C at a heating rate of 3°C / min in air atmosphere. Pre-calcine for 3 hours, then allow it to cool naturally to room temperature and remove the intermediate product.

[0079] Step 6: Grind the intermediate product obtained in Step 5 again for 20 minutes and put it back into the corundum crucible.

[0080] Step 7: Place the corundum crucible from Step 6 into a tube furnace and heat it to 1200°C at a heating rate of 5°C / min in air atmosphere. Calcinate at high temperature for 5 hours, and then cool it to room temperature with the furnace to obtain the calcined product.

[0081] Step 8: The calcined product obtained in Step 7 is subjected to graded grinding: first coarse grinding for 8 minutes, then fine grinding for 20 minutes, and then passing through a 300-mesh sieve to obtain near-infrared phosphor based on the energy resonance transfer effect.

[0082] Example 3

[0083] A near-infrared phosphor based on the energy resonance transfer effect, with a ZnGa2O4 matrix and Ca dopant ions. 2+ and In 3+ The doping concentration of all Ni is 1 mol%. 2+ and Ce 4+ The doping amounts are 0.8 mol% and 0.4 mol% respectively (i.e., a=0.01, x=0.008, y=0.004).

[0084] The preparation method of the near-infrared phosphor based on the energy resonance transfer effect is as follows:

[0085] Step 1: Weigh out zinc oxide (ZnO), nickel oxide (NiO), indium oxide (In2O3), calcium carbonate (CaCO3), and gallium oxide (Ga2O3) according to the stoichiometric ratio of each component element.

[0086] Step 2: Mix the raw materials weighed in Step 1 for the first time and place them in a planetary ball mill. Add 50 mL of anhydrous ethanol as the grinding medium and wet ball mill at 350 r / min for 3 h to obtain a slurry.

[0087] Step 3: Place the slurry obtained in Step 2 in a vacuum drying oven at 90℃ and dry it for 12 hours to obtain dried powder.

[0088] Step 4: Place the dried powder obtained in Step 3 into an agate mortar, add NH4Cl additive accounting for 1.0% of the total mass of the powder, and grind and mix again for 30 minutes to obtain the mixed precursor.

[0089] Step 5: Transfer the mixed precursor obtained in Step 4 to a corundum crucible, place it in a high-temperature tube furnace, and heat it to 500°C at a heating rate of 3°C / min in air atmosphere. Pre-calcine for 3 hours, then allow it to cool naturally to room temperature and remove the intermediate product.

[0090] Step 6: Grind the intermediate product obtained in Step 5 again for 20 minutes and put it back into the corundum crucible.

[0091] Step 7: Place the corundum crucible from Step 6 into a tube furnace and heat it to 1200°C at a heating rate of 5°C / min in air atmosphere. Calcinate at high temperature for 5 hours, and then cool it to room temperature with the furnace to obtain the calcined product.

[0092] Step 8: The calcined product obtained in Step 7 is subjected to graded grinding: first coarse grinding for 8 minutes, then fine grinding for 20 minutes, and then passing through a 300-mesh sieve to obtain near-infrared phosphor based on the energy resonance transfer effect.

[0093] Example 4

[0094] A near-infrared phosphor based on the energy resonance transfer effect, with a ZnGa2O4 matrix and Ca dopant ions. 2+ and In 3+ The doping concentration of all Ni is 9 mol%. 2+ and Ce 4+ The doping amounts are 0.8 mol% and 0.4 mol% respectively (i.e., a=0.09, x=0.008, y=0.004).

[0095] The preparation method of the near-infrared phosphor based on the energy resonance transfer effect is the same as steps 1-8 of Example 1.

[0096] Example 5

[0097] A near-infrared LED light-emitting device is prepared according to the following method: the near-infrared LED light-emitting device includes a packaging substrate, an LED chip, and a phosphor capable of effectively absorbing the light emitted by the LED chip and emitting near-infrared light; wherein, the near-infrared phosphor is the near-infrared phosphor of Example 1 above, and its chemical composition formula is: Zn 0.07 Ca 0.03 Ga 1.82 In 0.06 O4: 0.008Ni / 0.004Ce. The LED chip is an InGaN semiconductor chip with a peak emission wavelength of 370-380nm. Near-infrared phosphor is uniformly dispersed in a modified silicone adhesive (the mass ratio of near-infrared phosphor to modified silicone adhesive is 1:2.3), and then coated onto the chip (the chip is fixed on a packaging substrate) with a coating thickness of 200μm. The circuit is then connected, cured at 80℃ for 2 hours, and then further heated to 150℃ for 4 hours to obtain the near-infrared LED light-emitting device of this invention.

[0098] Single-factor experiments on key processes:

[0099] 1. Single-factor experiment on ball milling time

[0100] The process is basically the same as that in Example 1, except that the ball milling time in step 2 is set to 1h, 2h, 3h, 4h and 5h respectively. The results are shown in Table 1.

[0101] Table 1. Results of single-factor experiments on ball milling time

[0102]

[0103] The table above shows the following conclusions: When the ball milling time is less than 2 hours (e.g., 1 hour), the raw materials are mixed unevenly, resulting in large particle sizes (1200-1800 nm), insufficient solid-phase reaction, and low crystallinity (0.78), leading to a significant decrease in emission intensity and quantum efficiency (emission intensity only 62, IQY 28.3%). When the ball milling time is greater than 4 hours (e.g., 5 hours), excessive ball milling results in excessively fine particles (200-350 nm), a sharp increase in surface energy, easy particle agglomeration and impurity adsorption, and uncontrolled grain growth after calcination, which in turn reduces luminescence performance (emission intensity 76, IQY 30.5%). The optimal ball milling time range of this invention is 2-4 hours, with the optimal value being 3 hours.

[0104] 2. Single-factor experiment on pre-calcination temperature

[0105] The process was basically the same as in Example 1, except that the pre-calcination temperature was set to 300℃, 400℃, 500℃, 600℃ and 700℃ respectively. The results are shown in Table 2.

[0106] Table 2. Single-factor experimental results of pre-calcination temperature

[0107]

[0108] Conclusion and Analysis: When the pre-calcination temperature is below 400℃ (e.g., 300℃), precursors such as calcium carbonate decompose incompletely. The residual carbonate ions interfere with lattice formation during subsequent high-temperature calcination, generating impurity phases, resulting in an emission intensity of only 51 and an IQY of only 22.7%. When the pre-calcination temperature is above 600℃ (e.g., 700℃), the raw materials melt and sinter prematurely, forming localized glassy states, reducing the activity and uniformity of subsequent solid-phase reactions, causing the emission intensity to drop to 72 and the IQY to drop to 29.3%. The preferred pre-calcination temperature range of this invention is 400-600℃, with an optimal value of 500℃.

[0109] 3. Single-factor experiment on high-temperature calcination temperature

[0110] The process is basically the same as in Example 1, except that the high-temperature calcination temperature is set to 1000℃, 1150℃, 1200℃, 1250℃ and 1300℃ respectively. The results are shown in Table 3.

[0111] Table 3. Results of single-factor experiments on high-temperature calcination temperature

[0112]

[0113] Conclusion and Analysis: When the calcination temperature is below 1150℃ (e.g., 1100℃), the solid-state reaction kinetics are insufficient, the spinel crystal phase is not fully formed, and a large number of amorphous or intermediate phases exist, activating Ni ions. 2+It is difficult for the Ni to effectively enter the crystal lattice sites, resulting in an emission intensity of only 63 and an IQY of only 27.4%. When the calcination temperature exceeds 1250℃ (e.g., 1300℃), the grains grow excessively (800-1200nm), the specific surface area decreases, and some Ni... 2+ It may be oxidized or undergo grain boundary segregation, while the oxygen vacancy concentration increases, nonradiative recombination intensifies, the emission intensity drops to 84, and the IQY drops to 33.7%. The preferred high-temperature calcination temperature range of this invention is 1150-1250℃, with an optimal value of 1200℃.

[0114] 4. Single-factor experiment on high-temperature calcination time

[0115] The process is basically the same as that in Example 1, except that the high-temperature calcination time is set to 3h, 4h, 5h, 6h and 7h respectively. The results are shown in Table 4.

[0116] Table 4. Results of single-factor experiments on high-temperature calcination time

[0117]

[0118] Conclusion and analysis: When the calcination time is less than 4 hours (e.g., 3 hours), the solid-phase reaction is insufficient, and Ni... 2+ Ce 4+ Plasma failed to diffuse sufficiently into the crystal lattice, resulting in excessively high local concentrations that caused concentration quenching or the formation of impurity phases, leading to an emission intensity of only 72 and an IQY of only 30.8%. When the calcination time exceeded 6 hours (e.g., 7 hours), prolonged high-temperature treatment caused some Ce to be lost. 4+ Restored to Ce 3+ This process disrupts the original defect energy level structure, increases energy consumption and particle agglomeration, and reduces the emission intensity to 88 and IQY to 33.5%. The preferred calcination time range of this invention is 4-6 hours, with the optimal value being 5 hours.

[0119] 5. Single-factor experiment on the dosage of adjuvants

[0120] The process is basically the same as in Example 1, except that the amount of additives is set to 0wt%, 0.5wt%, 1.0wt%, 1.5wt%, and 2.0wt%, respectively. The results are shown in Table 5.

[0121] Table 5. Results of single-factor experiments on the dosage of adjuvants

[0122]

[0123] Conclusion and Analysis: Without additives, the solid-phase reaction is incomplete, resulting in loose sintering, low crystallinity (0.85), emission intensity of only 78, and IQY of only 33.2%. Additive dosage less than 0.5% shows some improvement; however, dosage greater than 1.5% (e.g., 2.0%) leads to over-sintering, resulting in the formation of a glassy phase, decreased crystallinity, emission intensity dropping to 82, and IQY decreasing to 34.1%. The preferred additive dosage range of this invention is 0.5-1.5%, with an optimal value of 1.0%.

[0124] 6. Single-factor experiment on pre-calcination time

[0125] The process is basically the same as that in Example 1, except that the pre-calcination time is set to 1h, 2h, 3h, 4h and 5h respectively. The results are shown in Table 6.

[0126] Table 6. Results of single-factor experiments on pre-calcination time

[0127]

[0128] Conclusion and Analysis: When the pre-calcination time is less than 2 hours (e.g., 1 hour), the carbonate decomposition is incomplete, resulting in an emission intensity of only 72 and an IQY of only 30.5%. When the time is greater than 4 hours (e.g., 5 hours), although decomposition is complete, some raw materials begin to sinter slightly, increasing energy consumption, and reducing the emission intensity to 89 and the IQY to 33.8%. The preferred pre-calcination time range of this invention is 2-4 hours, with the optimal value being 3 hours.

[0129] 7. Single-factor experiment on heating rate

[0130] The process is basically the same as that in Example 1, except that the heating rate in step 7 is set to 1℃ / min, 3℃ / min, 5℃ / min, 7℃ / min and 10℃ / min respectively. The results are shown in Table 7.

[0131] Table 7. Results of single-factor experiments on heating rate

[0132]

[0133] Conclusion and Analysis: When the heating rate is too slow (1℃ / min), the grain growth time is too long, the size is uneven, the emission intensity is only 78, and the IQY is only 32.5%. When the heating rate is too fast (10℃ / min), thermal stress leads to grain cracking and increased defects, resulting in significant unevenness, and the emission intensity drops to 82 and the IQY drops to 33.9%. The preferred heating rate range of this invention is 3-7℃ / min, with the optimal value being 5℃ / min.

[0134] 8. Single-factor experiment on the effect of graded grinding time

[0135] The process was basically the same as in Example 1, except that the grading grinding time was set to 10 min, 15 min, 20 min, 25 min and 30 min respectively. The results are shown in Table 8.

[0136] Table 8 Single-factor experiments on graded grinding time

[0137]

[0138] Conclusion Analysis: When the fine grinding time is less than 15 min (e.g., 10 min), the particles are too coarse (800-1000 nm), resulting in poor dispersibility, an emission intensity of only 85, and an IQY of only 35.1%. When the time is greater than 25 min (e.g., 30 min), the particles are too fine (200-350 nm), easily agglomerating and adsorbing impurities, increasing non-radiative transitions, and reducing the emission intensity to 86 and the IQY to 34.5%. The preferred fine grinding time range of this invention is 15-25 min, with an optimal value of 20 min. Furthermore, this application demonstrates through experiments that a longer grinding time is not necessarily better.

[0139] Comparative Examples 1-7

[0140] This comparative example provides several different Ni 2+ Ca 2+ In 3+ and Ce 4+ Near-infrared phosphor materials with varying doping concentrations, namely Zn 1-a Ca a Ga 2-2a-x-y In 2a O4:xNi / yCe, its preparation method is basically the same as in Example 1. The near-infrared phosphors of Comparative Examples 1-7 have the following specific compositions:

[0141] Comparative Example 1: The matrix is ​​ZnGa2O4, Ni 2+ and Ce 4+ All doping amounts were 0 mol%.

[0142] Comparative Example 2: The matrix is ​​ZnGa2O4, and the dopant ion is Ca. 2+ and In 3+ The doping concentration of all Ni is 3 mol%. 2+ The doping concentration is 0.8 mol%, Ce 4+ The doping amount is 0 mol%.

[0143] Comparative Example 3: The matrix is ​​ZnGa2O4, and the dopant ion is Ca. 2+ and In 3+ The doping concentration of all Ni is 3 mol%. 2+ Doping amount is 0 mol%, Ce 4+ The doping amount is 0.4 mol%.

[0144] Comparative Example 4: The matrix is ​​ZnGa2O4, Ni 2+ The doping concentration is 0.8 mol%, Ca 2+ and In 3+ The doping concentration of all samples is 1 mol%, Ce 4+ The doping amount is 0 mol%.

[0145] Comparative Example 5: The matrix is ​​ZnGa2O4, Ni 2+ The doping concentration is 0.8 mol%, Ca 2+ and In 3+ The doping concentration of all samples is 5 mol%, Ce 4+ The doping amount is 0 mol%.

[0146] Comparative Example 6: The matrix is ​​ZnGa2O4, Ni 2+ The doping concentration is 0.8 mol%, Ca 2+ and In 3+ The doping concentration of all samples was 7 mol%, Ce 4+ The doping amount is 0 mol%.

[0147] Comparative Example 7: The matrix is ​​ZnGa2O4, Ni 2+ The doping concentration is 0.8 mol%, Ca 2+ and In 3+ The doping concentration of all samples was 9 mol%, Ce 4+ The doping amount is 0 mol%.

[0148] Performance testing was conducted on the Ni provided in each embodiment and comparative example. 2+ The performance of the doped near-infrared phosphor and the corresponding near-infrared LED light-emitting device was measured.

[0149] Figure 1 This is a schematic diagram illustrating the ion substitution and crystal structure of the matrix material and modified phosphor of the present invention. The phosphor prepared by the present invention has an overall cubic spinel-type crystal structure. Figure 1 a is a schematic diagram of the ion substitution structure of the ZnCaInGaO matrix, where Ca is present in the matrix. 2+ preferentially replaces Zn in the crystal lattice 2+ These sites can effectively suppress the generation of oxygen vacancies inside the crystal lattice and reduce the defect concentration; Figure 1 b is a schematic diagram of the ionic substitution structure of Ni / Ce co-doped modified ZnCaInGaO:Ni / Ce phosphor, where the doping ion is Ni. 2+ Ce 4+ and In in the matrix 3+ All preferentially occupy Ga in the crystal lattice 3+ Sites are used to achieve uniform ion doping substitution and further optimize the lattice defect state.

[0150] Figure 2 This document presents the X-ray diffraction (XRD) patterns of samples with different doping concentrations and the Rietveld refined pattern of the optimally doped sample. Figure 2 a represents the XRD patterns of ZGN:Cl phosphors with different Cl doping concentrations. Figure 2 b shows the XRD patterns of ZGCI:Ni / Ce phosphors with different Ni / Ce co-doping concentrations; the XRD diffraction peaks of all samples correspond one-to-one with the cubic spinel structure standard card JCPDS38-1240, with no impurity peaks precipitated, and the diffraction peaks are sharp and have high diffraction intensity, proving that the samples of each doped system are pure phase structures with excellent crystal integrity and crystallinity. Figure 2 c represents the refined XRD pattern of the ZGN:Cl phosphor with optimal doping concentration. Figure 2 d represents the refined XRD pattern of the ZGCI:Ni / Ce phosphor with optimal doping concentration; the Rietveld structure of the sample was refined using Materials Studio software, and the resulting reliability factor (R) was determined. wp， R p The error margins are all less than 15.00%, which is within the industry's generally accepted confidence error range, further confirming that the optimal doped sample is a single-phase pure structure and that the doping modification did not destroy the intrinsic crystal structure of the matrix.

[0151] Figure 3 These are the near-infrared emission spectra of samples with different doping concentrations under 380 nm excitation conditions according to the present invention. Figure 3 a represents the luminescence spectra of ZGN:Cl phosphors with different Cl doping concentrations. Figure 3 b shows the emission spectra of ZGCI:Ni / Ce phosphors with different Ni / Ce co-doping concentrations. All doped samples produced near-infrared characteristic emission centered at 1300 nm. The excitation and emission peak shapes of each sample were basically the same, with only differences in relative emission intensity. Among the comparative samples, Comparative Example 1 had the highest emission intensity, while Example 1 of the present invention had the best emission intensity. The emission spectra of the samples effectively covered the 1100 nm-1650 nm near-infrared band. Compared with the single-doped system, Ce... 4+ / Ni 2+ The near-infrared emission intensity of the co-doped sample was significantly enhanced. Spectral characteristics showed that the 380 nm peak was due to Ni. 2+ of 3 A2( 3 F)→ 3 T1( 3 P) transition; a weak peak exists at 622nm. 3 A2( 3 F)→ 3 T1( 3 F) transition.

[0152] Figure 4 The images show a comparison of the fluorescence kinetics and electron paramagnetic resonance (EPR) characteristics of the sample with the optimal doping concentration according to this invention. Figure 4 a is a comparison of the time-resolved fluorescence spectra of ZGN:Cl phosphor and ZGCI:Ni / Ce phosphor at the optimal doping concentration. The fluorescence decay curves of each sample all show a single decay characteristic, proving that there is only a single near-infrared luminescent center in the sample system, and the luminescence mechanism is uniform and stable. Figure 4 b shows a comparison of the electron paramagnetic resonance (EPR) spectra of ZGN:Cl phosphor and ZGCI:Ni / Ce phosphor at the optimal doping concentration. The test results show that Ce 4+ After doping is introduced, it can interact with Ni in the crystal lattice. 2+ Significant interactions are generated, effectively regulating lattice defects and electronic states, thereby optimizing the luminescence performance of the sample.

[0153] Figure 5 This is a comparison of the luminescence intensity and quantum efficiency of mono-doped and co-doped samples at the optimal doping concentration of this invention. The excitation wavelength was 380 nm. Figure 5 a represents the luminescence intensity spectrum of the ZGCI:Ni single-doped phosphor with the optimal doping concentration, showing an internal quantum efficiency of 18.25% and an external quantum yield of 7.01%. Figure 5 b shows the luminescence intensity spectrum of the ZGCI:Ni / Ce co-doped phosphor with the optimal doping concentration, where the internal quantum efficiency is increased to 46.69% and the external quantum yield to 8.94%. Comparison shows that Ce... 4+ Co-doping modification can significantly improve the internal and external quantum yields of Ni-based phosphors and greatly optimize the near-infrared luminescence performance of the samples.

[0154] Figure 6 This document presents X-ray photoelectron spectroscopy (XPS) measurements and peak fitting diagrams of the O1s characteristic peaks for a series of samples from this invention, used to characterize the variation of oxygen vacancy content in the sample lattice. Figure 6 a is the XPS full spectrum test data of the ZGCI:Ni / Ce phosphor with the optimal doping concentration; Figure 6 b is the peak fitting diagram of the O1s characteristic peak of ZGO:Cl phosphor; Figure 6 c is the peak fitting spectrum of the O1s characteristic peak of ZGN:Ce phosphor; Figure 6 d represents the peak fitting spectrum of the O1s characteristic peak of the ZGCI:Ni / Ce phosphor. Test analysis shows that single Ca... 2+ In 3+ The doped system sample has a high lattice oxygen vacancy content, while the introduction of Ce 4+ Ni 2+Co-doping can effectively reduce the oxygen vacancy concentration in the system, reduce defect quenching centers, and improve the luminescence efficiency of the phosphor.

[0155] Figure 7 The temperature-dependent fluorescence spectrum and thermal activation energy fitting test spectrum of the sample with the optimal doping concentration of this invention are used to characterize the thermally stable luminescence performance of the sample. Among them, Figure 7 a is a temperature-varying fluorescence spectrum and luminescence intensity comparison diagram of ZGN:Cl phosphor and ZGCI:Ni / Ce phosphor with optimal doping concentration at different temperatures. In the low temperature range of 98K-245K, the samples of the present invention and the comparative samples both have excellent thermoluminescence stability, and some comparative samples also exhibit reverse thermal quenching characteristics. Figure 7 b shows the fitted spectra of the thermal activation energies of the two samples, which are 0.21 eV and 0.25 eV, respectively. Analysis shows that the reverse thermal quenching performance of the samples is due to the release of trapped photogenerated carriers by lattice oxygen vacancies after the temperature reaches the activation energy threshold, which compensates for the luminescence loss caused by thermal quenching and ensures the luminescence stability of the samples over a wide temperature range.

[0156] Figure 8 This is a schematic diagram illustrating the crystal field theory analysis and near-infrared luminescence mechanism of the phosphor of this invention. Wherein, Figure 8 a is the Tanabe-Sugano energy level diagram constructed based on the sample composition, which confirms that the phosphor system of the present invention is in a medium crystal field strength and has the theoretical basis for broadband near-infrared emission; Figure 8 Figure b shows a schematic diagram of the energy level transitions and luminescence mechanism of the ZGCI:Ni / Ce co-doped phosphor. Theoretical analysis indicates that its emission is broadband, with the crystal field strength located at the intermediate crystal field strength position. Under 380 nm ultraviolet light excitation, some electrons transition from the ground state of nickel ions... 3 A2( 3 F) Excited to nickel ions 3 T1( 3 The energy level of P). Then, the excited electrons transition from the P level via nonradiative transitions. 3 T1( 3 P) Return to 3 T2( 3 During the process of reaching the F) energy level, some of the excited electrons are captured by the formed oxygen vacancies, which is not conducive to further nonradiative transitions, while the other part transitions nonradiatively to the doped Ce. 4+ The defect energy level E that forms between the valence band and conduction band afterwards T Due to the defect energy level E T and 3 T2( 3 F) The energy levels are relatively close, allowing excited electrons to originate from the defect energy level E. T Transfer to 3 T2( 3F), and from 3 T2( 3 F) Jump to 3 A2( 3 The process of F) contributes to near-infrared (NIR) radiation, therefore, by doping Ce... 4+ Reducing the generation of oxygen vacancies and introducing new defect energy levels can significantly improve the near-infrared luminescence performance of materials, while oxygen vacancies can capture photocarriers, which is related to their reverse thermal quenching performance.

[0157] Figure 9 These are comparative test images of real-world imaging applications of the near-infrared LED light source prepared with phosphor according to Example 1 of this invention. Figure 9 Image a is a photograph of a fruit under visible light. Figure 9 b is a photograph of a human hand under visible light. Figure 9 c is a near-infrared image of fruit taken using the LED light source and near-infrared camera of this invention. Figure 9 Image d shows a near-infrared image of a human hand taken using the LED light source and near-infrared camera of this invention. The imaging results show that, relying on the near-infrared luminescence characteristics of the phosphor of this invention, the internal structure of fruits and details of deep tissues such as subcutaneous blood vessels in the human body can be clearly captured, with excellent imaging effects. This proves that the material of this invention can be applied to technical fields such as non-destructive testing of fruits and medical near-infrared imaging.

[0158] Figure 10 The images show the photoelectric performance test spectra of the pc-LED device prepared from the optimal doped sample in Example 1 of this invention under different driving currents. Figure 10 a represents the photoluminescence intensity variation curve of the device under different currents. The luminescence intensity of the device shows a positive increasing trend with the increase of the driving current, and the luminescence response is stable. Figure 10 b is the curve showing the change of device output power and photoelectric conversion efficiency with driving current. The device output power is positively correlated with the input driving current, and the output light power can be continuously increased as the current increases. The device photoelectric conversion efficiency is negatively correlated with the driving current, which is consistent with the photoelectric characteristics of conventional solid-state light-emitting devices. The overall device has stable working performance and strong practicality.

Claims

1. A method for preparing near-infrared phosphor based on energy resonance transfer effect, characterized in that, Includes the following steps: Step 1: According to the general chemical formula Zn 1-a Ca a Ga 2-2a-x-y In 2a O4: The stoichiometric ratio of xNi / yCe is used to weigh Zn source, Ca source, Ga source, In source, Ni source and Ce source as raw materials; Step 2: Mix the raw materials weighed in Step 1 for the first time and place them in a planetary ball mill. Add anhydrous ethanol as the grinding medium and wet ball mill at a speed of 300-400 r / min for 2-4 hours to obtain a slurry. Step 3: Place the slurry obtained in Step 2 in a vacuum drying oven at 80-100℃ and dry it for 10-14 hours to obtain a dried powder; Step 4: Place the dried powder obtained in Step 3 into an agate mortar, add 0.5-1.5% of the total powder mass of the additive, and grind and mix again for 20-40 minutes to obtain the mixed precursor; Step 5: Transfer the mixed precursor obtained in Step 4 to a crucible, place it in a tube furnace, and heat it to 400-600℃ in air atmosphere at a heating rate of 2-5℃ / min. Pre-calcine for 2-4 hours, then allow it to cool naturally to room temperature and remove the intermediate product. Step 6: Grind the intermediate product obtained in Step 5 again for 15-25 minutes and put it back into the crucible; Step 7: Place the crucible from Step 6 in a tube furnace and heat it to 1150-1250℃ in air at a heating rate of 3-7℃ / min. Calcine for 4-6 hours, then cool it to room temperature with the furnace to obtain the calcined product. Step 8: The calcined product obtained in Step 7 is subjected to graded grinding. First, coarse grinding for 5-10 minutes, then fine grinding for 15-25 minutes, and then passing through a 200-400 mesh sieve to obtain near-infrared phosphor based on the energy resonance transfer effect.

2. The method for preparing near-infrared phosphor based on energy resonance transfer effect according to claim 1, characterized in that, In step 1, the Zn source is ZnO, the Ca source is CaCO3, the Ga source is Ga2O3, the In source is In2O3, the Ni source is NiO, and the Ce source is CeO2.

3. The method for preparing near-infrared phosphor based on energy resonance transfer effect according to claim 1, characterized in that, The auxiliary agent mentioned in step 4 is NH4Cl or H3BO3.

4. The method for preparing near-infrared phosphor based on energy resonance transfer effect according to claim 1, characterized in that, In step 7, the calcination temperature is 1200℃ and the time is 5 hours.

5. A near-infrared phosphor based on the energy resonance transfer effect prepared by the preparation method according to any one of claims 1-4, characterized in that, The chemical formula of the near-infrared phosphor is: Zn 1-a Ca a Ga 2-2a-x-y In 2a O4: xNi / yCe, where 0.001≤a≤0.09, x=0.008, 0.002≤y≤0.

008.

6. The near-infrared phosphor based on energy resonance transfer effect according to claim 5, characterized in that, The near-infrared phosphor corresponds to a matrix with a cubic crystal system and a space group of Fd. m; the excitation wavelength range is 380-650nm, the emission wavelength range is 1100-1650nm, and the internal quantum efficiency is greater than 45%.

7. A near-infrared LED light-emitting device, characterized in that, The package includes a packaging substrate, an LED chip, and a near-infrared phosphor as described in claim 5 or 6 disposed on the surface of the LED chip, wherein the LED chip is disposed on the packaging substrate and the LED chip is a violet LED chip.

8. The near-infrared LED light-emitting device according to claim 7, characterized in that, The near-infrared phosphor and modified silicone adhesive are mixed at a mass ratio of 1:2-2.5 and then coated on the surface of the LED chip. The modified silicone adhesive is a compound of methyl phenyl vinyl silicone resin and hydrogen-containing silicone oil at a mass ratio of 10:

1. During the compounding process, the total mass of the compounding system is used as the calculation basis, and the amount of platinum catalyst added is 0.2wt%.

9. The near-infrared LED light-emitting device according to claim 7, characterized in that, The purple LED chip is an InGaN semiconductor chip.

10. The near-infrared LED light-emitting device according to claim 7, characterized in that, The thickness of the near-infrared phosphor coating on the LED chip surface is 100-300μm.

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