Luminescent material, preparation method thereof, and LED light source

Abstract

The present invention relates to the technical field of LED light source materials, and specifically provides a luminescent material, a preparation method thereof, and an LED light source. The luminescent material of the present invention is shown in Formula 1: Ca 1‑x Ge 4‑y‑z (PO4)6:xM,yR,zCr Formula 1; in Formula 1, M is selected from one or more of Mg, Sr, Ba, and Zn; R is selected from one or more of Sn, Si, Zr, and Ti; 0 ≤ x ≤ 1, 0 ≤ y ≤ 4, 0.0001 ≤ z ≤ 1. Compared with the prior art, the luminescent material of the present invention has a luminescence peak range of 650-850 nm, can be effectively excited by ultraviolet light and blue light, and has a relatively high near-infrared luminescence intensity; at the same time, the preparation process of the luminescent material is simple, the raw material cost is low, the product has stable chemical properties, is very fluffy and easy to grind, has no radioactivity, and will not cause harm to the environment.

Description

Technical Field

[0001] The present invention relates to the technical field of LED light source materials, and more specifically, to luminescent materials, their preparation methods, and LED light sources. Background Art

[0002] Near-infrared light sources can be applied to many fields such as modern agricultural lighting, food safety detection, security monitoring, photovoltaics, and spectral analysis technology. Near-infrared phosphor-converted LED light sources have become the preferred light sources due to their advantages such as low cost, compact structure, high radiation power, and adjustable emission spectra. Therefore, developing near-infrared luminescent materials with excellent luminescent properties is the key to realizing efficient near-infrared LED light sources. Cr 3+ Activated near-infrared phosphors have attracted much attention due to their many advantages such as easy synthesis, high matching degree of excitation spectra with blue LED chips, high internal quantum efficiency, and ultra-wideband tunable emission. There is a great demand for near-infrared luminescent materials in the domestic and international markets, and it is urgent to develop near-infrared luminescent materials with excellent properties. Summary of the Invention

[0003] In view of this, the purpose of the present invention is to provide luminescent materials, their preparation methods, and LED light sources. The luminescent peak range of the luminescent materials of the present invention is 650 - 850 nm, which can be effectively excited by ultraviolet light and blue light, and the generated near-infrared luminescence intensity is relatively high; at the same time, the preparation process of this luminescent material is simple, the raw material cost is low, the product has stable chemical properties, is very fluffy and easy to grind, has no radioactivity, and will not cause harm to the environment.

[0004] To achieve the above purpose, the present invention adopts the following technical solutions:

[0005] A luminescent material as shown in Formula 1,

[0006] Ca 1-x Ge 4-y-z (PO 4 ) 6 :xM,yR,zCr Formula 1;

[0007] In Formula 1, M is selected from one or more of Mg, Sr, Ba, and Zn;

[0008] R is selected from one or more of Sn, Si, Zr, and Ti;

[0009] 0 ≤ x ≤ 1, 0 ≤ y ≤ 4, 0.0001 ≤ z ≤ 1.

[0010] In the luminescent material of the present invention, chromium is trivalent chromium ions, M is divalent ions, and R is tetravalent ions.

[0011] In Formula 1 of the present invention, M is selected from one or more of Mg, Sr, and Zn;

[0012] R is selected from one or more of Sn, Si, and Ti;

[0013] 0 ≤ x ≤ 0.5, 0 ≤ y ≤ 1, 0.0001 ≤ z ≤ 0.1.

[0014] In Formula 1 of the present invention, M is Mg or Zn, preferably Zn;

[0015] R is selected from Si, Sn, or Ti, preferably Si or Sn, more preferably Sn;

[0016] 0 ≤ x ≤ 0.1, 0 ≤ y ≤ 0.1, 0.005 ≤ z ≤ 0.03; preferably, x = 0, y = 0, 0.005 ≤ z ≤ 0.03.

[0017] In the present invention, the chemical formula of the luminescent material is CaGe 3.99 (PO 4 ) 6 :0.01Cr, CaGe 4 (PO 4 ) 6 :0.01Cr, CaGe 3.59 (PO 4 ) 6 :0.01Cr, CaGe 3.99 (PO 4 ) 6 :0.05Cr, Ca 0.999 Ge 3.989 (PO 4 ) 6 :0.001Zn, 0.001Sn, 0.01Cr, Ca 0.98 Ge 3.99 (PO 4 ) 6 :0.01Cr, 0.02Mg, Ca 0.99 Ge 3.98 (PO 4 ) 6 :0.01Cr, 0.01Mg, 0.01Ti, CaGe 3.89 (PO 4 ) 6 :0.01Cr, 0.1Sn, CaGe 3.94 (PO 4 ) 6 :0.01Cr, 0.05Si or one or more thereof.

[0018] The present invention also provides a method for preparing the above luminescent material, including: mixing a calcium source, a germanium source, a chromium source, a phosphorus source, an M source, and an R source, and heating to obtain the luminescent material shown in Formula 1;

[0019] The M source and the R source are optionally added;

[0020] Ca 1-x Ge 4-y-z (PO 4 ) 6 : xM, yR, zCr Formula 1;

[0021] In Formula 1, M is selected from one or more of Mg, Sr, Ba, and Zn;

[0022] R is selected from one or more of Sn, Si, Zr, and Ti;

[0023] 0 ≤ x ≤ 1, 0 ≤ y ≤ 4, 0.0001 ≤ z ≤ 1.

[0024] In Formula 1 of the present invention, M is selected from one or more of Mg, Sr, and Zn;

[0025] R is selected from one or more of Sn, Si, and Ti;

[0026] 0 ≤ x ≤ 0.5, 0 ≤ y ≤ 1, 0.0001 ≤ z ≤ 0.1.

[0027] In Formula 1 of the present invention, M is Mg or Zn, preferably Zn;

[0028] R is selected from Si, Sn, or Ti, preferably Si or Sn, more preferably Sn;

[0029] 0 ≤ x ≤ 0.1, 0 ≤ y ≤ 0.1, 0.005 ≤ z ≤ 0.03; preferably, x = 0, y = 0, 0.005 ≤ z ≤ 0.03.

[0030] In the present invention, the chemical formula of the luminescent material is CaGe 3.99 (PO 4 ) 6 : 0.01Cr, CaGe 4 (PO 4 ) 6 : 0.01Cr, CaGe 3.59 (PO 4 ) 6 : 0.01Cr, CaGe 3.99 (PO 4 ) 6 : 0.05Cr, Ca 0.999 Ge 3.989 (PO 4 ) 6 : 0.001Zn, 0.001Sn, 0.01Cr, Ca 0.98 Ge 3.99 (PO 4 )6 : 0.01 Cr, 0.02 Mg, Ca 0.99 Ge 3.98 (PO 4 ) 6 : 0.01 Cr, 0.01 Mg, 0.01 Ti, CaGe 3.89 (PO 4 ) 6 : 0.01 Cr, 0.1 Sn, CaGe 3.94 (PO 4 ) 6 : One or more of 0.01 Cr, 0.05 Si.

[0031] The present invention has no special restrictions on the mixing. By using a method well-known to those skilled in the art, a calcium source, a germanium source, a chromium source, a phosphorus source, an M source, and an R source can be mixed.

[0032] After completing the mixing, the heating includes: preheating the mixed material at 400 - 500 °C, cooling, and then sintering the cooled mixed material at 800 °C - 1500 °C; the preheating time is 1 - 12 h, preferably 3 - 5 h; the sintering temperature is preferably 900 °C - 1200 °C, more preferably 1000 °C - 1100 °C, and the time is 1 - 24 h, preferably 3 - 12 h, and most preferably 8 - 10 h.

[0033] After completing the preheating, the present invention preferably cools the obtained product; preferably cools it to room temperature; the cooling method is natural cooling; preferably grinds the cooled product. After completing the sintering, the present invention preferably cools the obtained product; preferably cools it to room temperature; the cooling method is natural cooling; preferably grinds the cooled product.

[0034] In the present invention, the molar ratio of the calcium source, the germanium source, the phosphorus source, the chromium source, the M source, and the R source is (0.5 - 1.5):(3 - 5):(4 - 8):(0.001 - 0.1):(0 - 0.5):(0 - 0.5), preferably (0.8 - 1.2):(3.5 - 4.5):(5 - 7):(0.001 - 0.005):(0 - 0.1):(0 - 0.1).

[0035] In one embodiment of the present invention, the molar ratio of the calcium source, the germanium source, the phosphorus source, and the chromium source is 1:3.99:6:0.005.

[0036] In one embodiment of the present invention, the molar ratio of the calcium source, the germanium source, the phosphorus source, the chromium source, and the R source is 1:3.89:6:0.005:0.1.

[0037] In one embodiment of the present invention, the molar ratio of the calcium source, germanium source, phosphorus source, chromium source, and R source is 1:3.94:0.05:6:0.01.

[0038] In one embodiment of the present invention, the molar ratio of the calcium source, germanium source, phosphorus source, chromium source, and M source is 0.98:3.99:6:0.005:0.02.

[0039] In one embodiment of the present invention, the molar ratio of the calcium source, germanium source, phosphorus source, chromium source, M source, and R source is 0.99:3.98:6:0.005:0.01:0.01.

[0040] In one embodiment of the present invention, the molar ratio of the calcium source, germanium source, phosphorus source, and chromium source is 1:3.59:6:0.005.

[0041] In one embodiment of the present invention, the molar ratio of the calcium source, germanium source, phosphorus source, and chromium source is 1:3.99:6:0.05.

[0042] In the present invention, the chromium source includes one or more of chromium nitrate, phosphate, oxide, and chloride, preferably Cr 2 O 3 ;

[0043] The calcium source includes one or more of calcium oxide, carbonate, and nitrate, preferably CaCO 3 ;

[0044] The germanium source includes germanium oxide, preferably GeO 2 ;

[0045] The phosphorus source includes ammonium phosphate, preferably NH4H2PO4.

[0046] In the present invention, the M source includes one or more of the oxide, carbonate, and nitrate of the M element, preferably the oxide of the M element, more preferably MgO;

[0047] The R source includes one or more of the oxide, carbonate, and nitrate of the R element, preferably the oxide of the R element, more preferably SiO 2 、SnO 2 or TiO 2 。

[0048] In the present invention, the heating is carried out in an atmosphere; the atmosphere includes air, nitrogen, argon, or hydrogen-containing gas, preferably nitrogen or air.

[0049] The present invention also provides the above LED light source, including the above luminescent material. The LED light source of the present invention further includes a blue light chip.

[0050] The luminescent material Ca 1-x Ge 4-y-z (PO 4 ) 6 :xM,yR,zCr provided by the present invention is a near-infrared luminescent material based on calcium germanium phosphate as the basic component, trivalent chromium ions as luminescent ions, and divalent and tetravalent ions co-doped. Compared with the prior art, the luminescent peak range of the luminescent material of the present invention is 650-850 nm, which can be effectively excited by ultraviolet light and blue light, and the generated near-infrared luminescence intensity is relatively high; at the same time, the preparation process of the luminescent material is simple, the raw material cost is low, the chemical properties of the product are stable, fluffy and very easy to grind, non-radioactive, and will not cause harm to the environment. Brief Description of the Drawings

[0051] Figure 1 is the X-ray powder diffraction pattern of the luminescent material provided in Example 1 of the present invention;

[0052] Figure 2 is the excitation and emission spectrum of the luminescent material provided in Example 1 of the present invention;

[0053] Figure 3 is the emission spectrum of the luminescent materials provided in Example 1 and Example 12 of the present invention. Detailed Embodiments

[0054] Next, the technical solutions of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

[0055] To further illustrate the present invention, the following examples are used for detailed description. All the raw materials used in the following examples of the present invention are commercially available products.

[0056] Example 1

[0057] The raw materials are CaCO 3 (analytical pure), GeO 2 (analytical pure), NH4H2PO4 (analytical pure), Cr 2 O 3 (spectral pure), and their molar ratio is 1:3.99:6:0.005. Weigh the raw materials according to the above ratio, mix them evenly and place them in a corundum crucible, pre-burn at 400 °C for 5 hours, cool and then grind and place them back into the crucible, and then put them into a high-temperature furnace and roast at 1050 °C in an air atmosphere for 10 hours, and naturally cool to room temperature to obtain a near-infrared luminescent powder. The obtained near-infrared fluorescent powder is a white powder, and its molecular formula is CaGe3.99 (PO 4 ) 6 : 0.01 Cr, as Figure 1 shown; both its excitation and emission spectra are broadband emissions, and the maximum excitation peak is located at around 435 nm, as Figure 2 shown; under the excitation of 435 nm blue light, the maximum emission wavelength of the phosphor is located near 747 nm, and the emission is near-infrared light.

[0058] Example 2

[0059] The raw materials are CaCO 3 (analytical pure), GeO 2 (analytical pure), NH4H2PO4 (analytical pure), Cr 2 O 3 (spectral pure), and their molar ratio is 1: 3.99: 6: 0.005. Weigh the raw materials according to the above ratio, mix them evenly and place them in a corundum crucible, pre-burn at 400 °C for 5 hours, cool and grind them again and place them in the crucible, then put them into a high-temperature furnace and roast at 1150 °C in an air atmosphere for 10 hours, and naturally cool to room temperature to obtain a near-infrared phosphor. The obtained near-infrared phosphor is a white powder, and its molecular formula is CaGe 3.99 (PO 4 ) 6 : 0.01 Cr; both its excitation and emission spectra are broadband emissions, and the maximum excitation peak is located at around 435 nm; under the excitation of 435 nm blue light, the maximum emission wavelength of the phosphor is located near 747 nm, and the emission is near-infrared light.

[0060] Example 3

[0061] The raw materials are CaCO 3 (analytical pure), GeO 2 (analytical pure), NH4H2PO4 (analytical pure), Cr 2 O 3 (spectral pure), and their molar ratio is 1: 3.99: 6: 0.005. Weigh the raw materials according to the above ratio, mix them evenly and place them in a corundum crucible, pre-burn at 400 °C for 5 hours, cool and grind them again and place them in the crucible, then put them into a high-temperature furnace and roast at 1050 °C in a nitrogen atmosphere for 10 hours, and naturally cool to room temperature to obtain a near-infrared phosphor. The obtained near-infrared phosphor is a white powder, and its molecular formula is CaGe 3.99 (PO 4 ) 6 : 0.01 Cr; both its excitation and emission spectra are broadband emissions, and the maximum excitation peak is located at around 435 nm; under the excitation of 435 nm blue light, the maximum emission wavelength of the phosphor is located near 747 nm, and the emission is near-infrared light.

[0062] Example 4

[0063] The raw materials are CaCO 3 (analytical pure), GeO 2 (analytical pure), NH4H2PO4 (analytical pure), Cr 2 O 3 (spectral pure). Their molar ratio is 1:3.99:6:0.005. Weigh the raw materials according to the above ratio, mix them evenly and put them into a corundum crucible. Pre-bake at 400 °C for 5 hours, cool and grind them again and put them into the crucible, then put them into a high-temperature furnace and bake in air atmosphere at 1050 °C for 8 hours, and cool naturally to room temperature to obtain a near-infrared luminescent powder. The obtained near-infrared fluorescent powder is a white powder, and its molecular formula is CaGe 3.99 (PO 4 ) 6 :0.01Cr; its excitation and emission spectra are both broadband emissions, and the maximum excitation peak is located at about 435 nm; under the excitation of 435 nm blue light, the maximum emission wavelength of the fluorescent powder is located near 747 nm, and the emission is near-infrared light.

[0064] Example 5

[0065] The raw materials are CaCO 3 (analytical pure), GeO 2 (analytical pure), (NH4)2HPO4 (analytical pure), Cr 2 O 3 (spectral pure). Their molar ratio is 1:3.99:6:0.005. Weigh the raw materials according to the above ratio, mix them evenly and put them into a corundum crucible. Pre-bake at 400 °C for 5 hours, cool and grind them again and put them into the crucible, then put them into a high-temperature furnace and bake in air atmosphere at 1050 °C for 10 hours, and cool naturally to room temperature to obtain a near-infrared luminescent powder. The obtained near-infrared fluorescent powder is a white powder, and its molecular formula is CaGe 3.99 (PO 4 ) 6 :0.01Cr; its excitation and emission spectra are both broadband emissions, and the maximum excitation peak is located at about 435 nm; under the excitation of 435 nm blue light, the maximum emission wavelength of the fluorescent powder is located near 747 nm, and the emission is near-infrared light.

[0066] Example 6

[0067] The raw materials are CaCO 3 (analytical pure), GeO 2 (analytical pure), NH4H2PO4 (analytical pure), Cr 2 O 3 (spectral pure), SnO 2(Analytical pure), and the molar ratio between them is 1:3.89:6:0.005:0.1. Weigh the raw materials according to the above ratio, mix them evenly and put them into a corundum crucible. Pre-bake at 400 °C for 5 hours, cool down, grind them again and put them into the crucible, then put them into a high-temperature furnace and bake at 1050 °C in an air atmosphere for 10 hours, and naturally cool to room temperature to obtain a near-infrared luminescent powder. The obtained near-infrared phosphor is a white powder, and its molecular formula is CaGe 3.89 (PO 4 ) 6 :0.01Cr,0.1Sn; both its excitation and emission spectra are broadband emissions, and the maximum excitation peak is located at about 435 nm; under the excitation of 435 nm blue light, the maximum emission wavelength of the phosphor is located near 747 nm, and the emission is near-infrared light.

[0068] Example 7

[0069] The raw materials are CaCO 3 (Analytical pure), GeO 2 (Analytical pure), NH4H2PO4 (Analytical pure), Cr 2 O 3 (Spectral pure), MgO (Analytical pure), and the molar ratio between them is 0.98:3.99:6:0.005:0.02. Weigh the raw materials according to the above ratio, mix them evenly and put them into a corundum crucible. Pre-bake at 400 °C for 5 hours, cool down, grind them again and put them into the crucible, then put them into a high-temperature furnace and bake at 1050 °C in an air atmosphere for 10 hours, and naturally cool to room temperature to obtain a near-infrared luminescent powder. The obtained near-infrared phosphor is a white powder, and its molecular formula is Ca 0.98 Ge 3.99 (PO 4 ) 6 :0.01Cr,0.02Mg; both its excitation and emission spectra are broadband emissions, and the maximum excitation peak is located at about 435 nm; under the excitation of 435 nm blue light, the maximum emission wavelength of the phosphor is located near 747 nm, and the emission is near-infrared light.

[0070] Example 8

[0071] The raw materials are CaCO 3 (Analytical pure), GeO 2 (Analytical pure), NH4H2PO4 (Analytical pure), Cr 2 O 3(Spectral purity), and the molar ratio between them is 1:3.99:6:0.005. Weigh the raw materials according to the above ratio, mix them evenly and put them into a corundum crucible. Pre-bake at 400 °C for 5 hours, cool down, grind again and put them into the crucible, then put them into a high-temperature furnace and bake in an air atmosphere at 1050 °C for 10 hours, and naturally cool to room temperature to obtain a near-infrared luminescent powder. The obtained near-infrared fluorescent powder is a white powder, and its molecular formula is CaGe 3.99 (PO 4 ) 6 :0.01Cr; both its excitation and emission spectra are broadband emissions, and the maximum excitation peak is located at about 435 nm; under the excitation of 435 nm blue light, the maximum emission wavelength of the fluorescent powder is located near 747 nm, and the emission is near-infrared light.

[0072] Example 9

[0073] The raw materials are CaCO 3 (Analytical purity), GeO 2 (Analytical purity), NH4H2PO4 (Analytical purity), Cr 2 O 3 (Spectral purity), MgO (Analytical purity), TiO 2 (Analytical purity), and the molar ratio between them is 0.99:3.98:6:0.005:0.01:0.01. Weigh the raw materials according to the above ratio, mix them evenly and put them into a corundum crucible. Pre-bake at 400 °C for 5 hours, cool down, grind again and put them into the crucible, then put them into a high-temperature furnace and bake in an air atmosphere at 1050 °C for 10 hours, and naturally cool to room temperature to obtain a near-infrared luminescent powder. The obtained white near-infrared fluorescent powder has a molecular formula of Ca 0.99 Ge 3.98 (PO 4 ) 6 :0.01Cr, 0.01Mg, 0.01Ti; both its excitation and emission spectra are broadband emissions, and the maximum excitation peak is located at about 435 nm; under the excitation of 435 nm blue light, the maximum emission wavelength of the fluorescent powder is located near 747 nm, and the emission is near-infrared light.

[0074] Example 10

[0075] The raw materials are CaCO 3 (Analytical purity), GeO 2 (Analytical purity), NH4H2PO4 (Analytical purity), Cr 2 O 3(Spectroscopic pure), and the molar ratio between them is 1:3.59:6:0.005. Weigh the raw materials according to the above ratio, mix them evenly and put them into a corundum crucible. Pre-burn at 400 °C for 5 hours, cool down, grind again and put them into the crucible, then put them into a high-temperature furnace and roast in an air atmosphere at 1050 °C for 10 hours, and naturally cool to room temperature to obtain a near-infrared luminescent powder. The obtained near-infrared phosphor is a white powder, and its molecular formula is CaGe 3.59 (PO 4 ) 6 :0.01Cr; both its excitation and emission spectra are broadband emissions, and the maximum excitation peak is located at about 435 nm; under the excitation of 435 nm blue light, the maximum emission wavelength of the phosphor is located near 747 nm, and the emission is near-infrared light.

[0076] Example 11

[0077] The raw materials are CaCO 3 (Analytical pure), GeO 2 (Analytical pure), NH4H2PO4 (Analytical pure), Cr 2 O 3 (Spectroscopic pure), and the molar ratio between them is 1:3.99:6:0.05. Weigh the raw materials according to the above ratio, mix them evenly and put them into a corundum crucible. Pre-burn at 400 °C for 5 hours, cool down, grind again and put them into the crucible, then put them into a high-temperature furnace and roast in an air atmosphere at 1050 °C for 10 hours, and naturally cool to room temperature to obtain a near-infrared luminescent powder. The obtained near-infrared phosphor is a white powder, and its molecular formula is CaGe 3.99 (PO 4 ) 6 :0.05Cr; both its excitation and emission spectra are broadband emissions, and the maximum excitation peak is located at about 435 nm; under the excitation of 435 nm blue light, the maximum emission wavelength of the phosphor is located near 747 nm, and the emission is near-infrared light.

[0078] Example 12

[0079] The raw materials are CaCO 3 (Analytical pure), GeO 2 (Analytical pure), SiO 2 (Analytical pure), NH4H2PO4 (Analytical pure), Cr 2 O 3(Spectral purity), and the molar ratio between them is 1:3.94:0.05:6:0.01. Weigh the raw materials according to the above ratio, mix them evenly and put them into a corundum crucible. Pre-bake at 400 °C for 5 hours, grind them again after cooling and put them back into the crucible, then put them into a high-temperature furnace and bake at 1050 °C in an air atmosphere for 10 hours, and naturally cool to room temperature to obtain a near-infrared luminescent powder. The obtained near-infrared phosphor is a white powder, and its molecular formula is CaGe 3.94 (PO 4 ) 6 :0.01Cr, 0.05Si; both its excitation and emission spectra are broadband emissions, and the maximum excitation peak is located at about 435 nm; under the excitation of 435 nm blue light, the maximum emission wavelength of the phosphor is located near 747 nm, and the emission is near-infrared light, as Figure 3 shown.

[0080] The above description of the embodiments disclosed enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A luminescent material as shown in Formula 1, CaGe 3.99 (PO 4 ) 6 : 0.01Cr Formula 1.

2. A method for preparing a luminescent material, characterized in that, comprising: mixing a calcium source, a germanium source, a chromium source and a phosphorus source to obtain a mixture, and heating to obtain the luminescent material as shown in Formula 1; the heating includes: preheating the mixture at 400-500 °C, cooling, and then sintering the cooled mixture at 800 °C - 1500 °C; CaGe 3.99 (PO 4 ) 6 : 0.01Cr Formula 1.

3. The method for preparing a luminescent material according to claim 2, characterized in that, the preheating time is 1-12 h; the sintering time is 1-24 h.

4. The method for preparing a luminescent material according to claim 2, characterized in that, the chromium source includes one or more of chromium nitrate, phosphate, oxide, chloride; the calcium source includes one or more of calcium oxide, carbonate, nitrate; the germanium source includes germanium oxide; the phosphorus source includes ammonium phosphate salt.

5. An LED light source, characterized in that, it includes the luminescent material described in claim 1 or the luminescent material prepared by the method for preparing a luminescent material according to any one of claims 2-4.

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