Near ultraviolet excited niobium-based garnet broadband near-infrared fluorescent powder and preparation method thereof

Abstract

The invention discloses near ultraviolet excited niobium-based garnet broadband near-infrared fluorescent powder, which is characterized in that the chemical composition expression formula of the fluorescent powder is LuCa2Ga4-xNbO12: xCr < 3 + >, x is the substitution amount of Cr, and x is more than or equal to 0 and less than 1. The fluorescent powder can be excited by 250-700nm near ultraviolet-visible light, the emission peak covers 600nm-850nm, the near infrared luminous intensity of the fluorescent powder under the excitation of near ultraviolet light is far higher than the luminous intensity of the fluorescent powder under the excitation of blue light, the near ultraviolet excitation peak intensity is far higher than the blue light excitation peak intensity, and the fluorescent powder can be used for preparing the fluorescent powder. The fluorescence lifetime under near ultraviolet excitation is longer than the fluorescence lifetime under blue light excitation, and the material can be used in the fields of medical imaging, key information identification, plant growth illumination and the like, and can be used as a near-infrared light conversion material excited by near ultraviolet and blue light LED chips.

Description

Technical field:

[0001] The present invention relates to the technical field of inorganic luminescent materials, and in particular to a niobium-based garnet broadband near-infrared phosphor excited by near-ultraviolet light and a preparation method thereof. Background technology:

[0002] Broadband near-infrared light has broad application prospects in biomedicine, pesticide residues, artificial intelligence, drone imaging, and security monitoring. Compared to traditional near-infrared light sources, near-infrared phosphor-converted LEDs (NIR pc-LEDs) offer numerous advantages, including adjustable emission peaks, low cost, long life, energy conservation and environmental protection, and high luminous efficiency, making them a research hotspot in recent years.

[0003] Among the near-infrared light-activated ions, the near-infrared emission of rare earth ions is mostly narrow-band emission with weak absorption and low luminescence efficiency, which cannot meet the demand for broadband near-infrared light sources in fields such as food testing and biomedicine. 3+ It can be well excited by ultraviolet and visible light and can achieve broadband and efficient near-infrared emission, making it an ideal broadband near-infrared light activator. Combined with the garnet matrix, it has the advantages of easy structural adjustment, good thermal stability and abundant polyhedral sites, which can be used for Cr 3+ Ions provide a good crystal field environment, thus achieving efficient, broadband near-infrared luminescence. For example, the inventor's previous achievements CN117965166A and CN117965167A, CN117965166A discloses a lutetium calcium gallium tin garnet-based broadband near-infrared phosphor with adjustable thermal stability. The chemical composition of the phosphor is: Lu 2+x Ca 1-x Ga 3.965+x Sn 1- x O 12 :0.035Cr 3+ , where 0≤x<1, the phosphor can be excited by blue-green light of 360-540nm and red light of 560-700nm, with emission peaks ranging from 600nm to 850nm, and the emission peak position, width and thermal stability of luminescence are adjustable. Its luminous intensity increases with increasing temperature between 25-150℃ (298-423K), and can reach up to 142% of that at room temperature at 150℃. It has the advantages of high luminous brightness, adjustable thermal stability, short fluorescence lifetime, simple synthesis, and low energy consumption. CN117965167A discloses a high thermal stability lutetium calcium gallium silicon garnet-based broadband near-infrared phosphor, the chemical composition of which is expressed as: Lu 2+ x Ca 1-x Ga 3.98+x Si 1-x O12 :0.02Cr 3+ , where 0≤x<1, can be excited by blue-green light of 350-550nm, red light of 550-690nm and X-rays, the emission peak covers 600nm to 850nm, and exhibits anomalous luminescence thermal quenching phenomenon.

[0004] However, currently Cr 3+ Activated garnet broadband near-infrared phosphors are mostly excited by blue light, and their luminescence intensity under near-ultraviolet light excitation is generally weak. Summary of the invention:

[0005] The present invention aims to provide a niobium-based garnet broadband near-infrared phosphor excited by near-ultraviolet light.

[0006] The present invention is achieved through the following technical solutions:

[0007] A near-ultraviolet-excited niobium-based garnet broadband near-infrared phosphor, characterized in that the chemical composition of the phosphor is: LuCa2Ga 4-x NbO 12 :xCr 3+ , wherein x is the substitution amount of Cr, and 0≤x<1, preferably 0.01≤x≤0.07.

[0008] The preparation method of the niobium-based garnet broadband near-infrared phosphor is characterized by comprising the following steps: weighing raw materials containing lutetium, calcium, gallium, niobium and chromium elements according to their chemical composition, wherein the stoichiometric ratio of the metal elements lutetium, calcium, gallium, niobium and chromium is 1:2:4-x:1:x, wherein x is the substitution amount of Cr and 0≤x<1, grinding and mixing them uniformly, placing them in a reaction container, sintering them at 1150-1450°C in an air atmosphere, cooling them to room temperature, and grinding them to obtain the target phosphor.

[0009] Preferably, the sintering step is: heating to 1350° C. at a rate of 3-5° C. / min in an air atmosphere, keeping the temperature constant for 6 hours, then cooling to room temperature, and grinding to obtain the target phosphor.

[0010] Preferably, the raw material containing lutetium element is selected from one or more of lutetium oxide, lutetium oxalate, lutetium carbonate and lutetium nitrate.

[0011] Preferably, the raw material containing calcium is selected from one or more of calcium carbonate, calcium bicarbonate and calcium oxalate.

[0012] Preferably, the raw material containing gallium element is selected from gallium oxide.

[0013] Preferably, the raw material containing niobium element is selected from niobium oxide.

[0014] Preferably, the raw material containing chromium element is selected from one or more of chromium oxide and chromium nitrate.

[0015] The present invention also protects the application of the niobium-based garnet broadband near-infrared luminescent phosphor in the fields of medical imaging, key information identification and plant growth lighting.

[0016] The present invention also protects the use of the niobium-based garnet broadband near-infrared luminescent phosphor as a near-infrared light conversion material excited by near-ultraviolet and blue light LED chips.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] (1) The phosphor of the present invention can be excited by near-ultraviolet-visible light of 250-700 nm, and its emission peak covers 600 nm to 850 nm. Its near-infrared luminescence intensity under near-ultraviolet light excitation is much higher than its luminescence intensity under blue light excitation. Specifically, its luminescence intensity under 310 nm excitation is 2.62 times that under blue light (450 nm) excitation; and Lu3Ga5O 12 :0.03Cr 3+ The luminescence intensity under 310nm excitation is only 3.8% of that under blue light (450nm) excitation.

[0019] (2) The near-ultraviolet excitation peak intensity of the phosphor of the present invention is much higher than the blue light excitation peak intensity. Specifically, the excitation peak intensity at 310 nm is 2.67 times that at 450 nm, and the near-ultraviolet excitation peak intensity is adjustable.

[0020] (3) The fluorescence lifetime of the phosphor of the present invention under near-ultraviolet light excitation is longer than that under blue light excitation.

[0021] (4) The phosphor of the present invention has the advantages of simple synthesis, low energy consumption, and high luminous intensity under near-ultraviolet light excitation. It can be used in the fields of medical imaging, key information identification, and plant growth lighting, and can be used as a near-infrared light conversion material excited by near-ultraviolet and blue light LED chips. Description of the drawings:

[0022] Figure 1 The Cr prepared in Example 1 3+ The X-ray powder diffraction pattern of the niobium-doped garnet near-infrared phosphor shows that the obtained sample is pure phase.

[0023] Figure 2 The Cr prepared in Example 2 3+ Comparison of the fluorescence emission spectra of the niobium-doped garnet near-infrared phosphor under 310nm and 450nm excitation. As can be seen from the figure, the luminescence intensity under 310nm excitation is 2.62 times that under 450nm excitation.

[0024] Figure 3 The fluorescence emission spectra of Example 1 under 310nm and 450nm excitation are compared. It can be seen from the figure that Lu3Ga5O 12 :0.03Cr 3+ The luminescence intensity under 310nm excitation is only 3.8% of that under 450nm excitation.

[0025] Figure 4 2 are the fluorescence excitation spectra of Example 2 and Comparative Example 1. As can be seen from the figure, the peak excitation intensity of Example 2 at 310 nm is 2.67 times that of the peak excitation intensity at 450 nm.

[0026] Figure 5 The Cr prepared in Example 3 3+ Comparison of the fluorescence lifetimes of niobium-doped garnet near-infrared phosphors under 310nm and 450nm excitation. The figure shows that the fluorescence lifetime under near-ultraviolet light excitation is longer than that under blue light excitation. Specific implementation method:

[0027] The following is a further description of the present invention, but not a limitation of the present invention.

[0028] Example 1:

[0029] Weigh 0.9948g of lutetium oxide (Lu2O3), 1.8416g of gallium oxide (Ga2O3), 1.0009g of calcium carbonate (CaCO3), 0.6645g of niobium oxide (Nb2O5), and 0.0266g of chromium oxide (Cr2O3) respectively, grind the above raw materials evenly in an agate mortar, place them in a corundum crucible, and heat them from room temperature to 1150℃ in an atmospheric pressure air atmosphere at a heating rate of 5℃ / min. After reaching the preset temperature, keep the temperature constant for 6h, wait for it to cool naturally, and grind it evenly to obtain LuCa2Ga 3.93 NbO 12 :0.07Cr 3+ near-infrared phosphors.

[0030] Example 2

[0031] Weigh 0.9948g of lutetium oxide (Lu2O3), 1.8604g of gallium oxide (Ga2O3), 1.0009g of calcium carbonate (CaCO3), 0.6645g of niobium oxide (Nb2O5), and 0.0114g of chromium oxide (Cr2O3) respectively, grind the above raw materials evenly in an agate mortar, place them in a corundum crucible, and heat them from room temperature to 1350℃ in an atmospheric pressure air atmosphere at a heating rate of 5℃ / min. After reaching the preset temperature, keep the temperature constant for 6h, wait for it to cool naturally, and grind it evenly to obtain LuCa2Ga3.97 NbO 12 :0.03Cr 3+ near-infrared phosphors.

[0032] Example 3

[0033] Weigh 0.9948g of lutetium oxide (Lu2O3), 1.8698g of gallium oxide (Ga2O3), 1.0009g of calcium carbonate (CaCO3), 0.6645g of niobium oxide (Nb2O5), and 0.0038g of chromium oxide (Cr2O3) respectively, grind the above raw materials evenly in an agate mortar, place them in a corundum crucible, and heat them from room temperature to 1450℃ in an atmospheric pressure air atmosphere at a heating rate of 5℃ / min. After reaching the preset temperature, keep the temperature constant for 6h, wait for it to cool naturally, and grind it evenly to obtain LuCa2Ga 3.99 NbO 12 :0.01Cr 3+ near-infrared phosphors.

[0034] Comparative Example 1

[0035] Weigh 2.9845g of lutetium oxide (Lu2O3), 2.3290g of gallium oxide (Ga2O3), and 0.0114g of chromium oxide (Cr2O3) respectively, grind them evenly in an agate mortar, place them in a corundum crucible, and heat them from room temperature to 1350℃ in an atmospheric air atmosphere at a heating rate of 5℃ / min. After reaching the preset temperature, keep the temperature constant for 6h, let it cool naturally, and grind them evenly to obtain Lu3Ga 4.97 O 12 :0.03Cr 3+ near-infrared phosphors.

Claims

1. A near-ultraviolet-excited niobium-based garnet broadband near-infrared phosphor, characterized in that: The chemical composition of the phosphor is: LuCa2Ga 4-x NbO 12 :xCr 3+ , where x is the substitution amount of Cr, and 0≤x<1.

2. The near-infrared phosphor according to claim 1, characterized in that 0.01≤x≤0.07。 3. The method for preparing the niobium-based garnet broadband near-infrared phosphor according to claim 1, characterized in that: The following steps are involved: Raw materials containing lutetium, calcium, gallium, niobium and chromium elements are weighed respectively according to their chemical composition, wherein the stoichiometric ratio of the metal elements lutetium, calcium, gallium, niobium and chromium is 1:2:4-x:1:x, wherein x is the substitution amount of Cr and 0≤x<1. The raw materials are fully ground and mixed, placed in a reaction container, sintered at 1150-1450°C in an air atmosphere, cooled to room temperature, and ground to obtain the target phosphor.

4. The method for preparing the near-infrared phosphor according to claim 2, wherein: The sintering step is: heating to 1350° C. at a rate of 3-5° C. / min in an air atmosphere, keeping the temperature constant for 6 hours, cooling to room temperature, and grinding to obtain the target phosphor.

5. The method for preparing the near-infrared phosphor according to claim 2, wherein: The raw material containing lutetium element is selected from one or more of lutetium oxide, lutetium oxalate, lutetium carbonate and lutetium nitrate.

6. The method for preparing the near-infrared phosphor according to claim 2, wherein: The raw material containing calcium element is selected from one or more of calcium carbonate, calcium bicarbonate and calcium oxalate.

7. The method for preparing the near-infrared phosphor according to claim 2, wherein: The raw material containing gallium element is selected from gallium oxide.

8. The method for preparing the near-infrared phosphor according to claim 2, wherein: The raw material containing niobium is selected from niobium oxide; the raw material containing chromium is selected from at least one of chromium oxide and chromium nitrate.

9. Application of the niobium-based garnet broadband near-infrared luminescent phosphor according to claim 1 in the fields of medical imaging, key information recognition and plant growth lighting.

10. Use of the niobium-based garnet broadband near-infrared luminescent phosphor according to claim 1 as a near-infrared light conversion material excited by near-ultraviolet and blue light LED chips.

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