Europium-doped sodium manganite mica red luminescent material, preparation method and application thereof

Abstract

This invention relates to the field of red luminescent materials, specifically disclosing a europium-doped sodium manganese mica red luminescent material, its preparation method, and its applications. The general chemical formula of the europium-doped sodium manganese mica red luminescent material is NaMg. a Mn 3‑a AlSi3O 10 F2:xEu 2+ x = 2 mol%–5 mol%, a = 2.4–2.8. This invention uses sodium manganese mica as the luminescent matrix and Eu... 2+ As a sensitizer, some of the Mg atoms in fluorophlogopite are located in octahedral positions. 2+ Mn 2+ Replaced by Mn 2+ It appears in the matrix as an activator; Eu 2+ Doping into the matrix, in Eu 2+ →Mn 2+ Under the action of energy transfer, Mn 2+ The red light emission is greatly enhanced; through Na + interlayer cations K in manganese mica + By exchanging and regulating the lattice of the mica matrix, europium-doped sodium manganese mica red luminescent material has great application potential in the field of LEDs for plant growth.

Description

Technical Field

[0001] This invention relates to the field of red fluorescent materials, and more particularly to a europium-doped sodium manganese mica red luminescent material, its preparation method, and its application. Background Technology

[0002] Key parameters for plant growth include spectral range, duration of illumination, and light intensity. Sunlight provides the energy needed for photosynthesis and regulates plant life activities such as seed germination and stem / leaf growth. However, sunlight is difficult to control artificially; therefore, controllable artificial light sources are needed to better promote plant growth. Among current plant lighting devices, light-emitting diodes (LEDs) have advantages such as controllable light color, long lifespan, low radiant heat, and environmental friendliness, making them the primary artificial light source for plant cultivation. Research shows that photoreceptors in the red and far-red light regions of plants are phytochromes, primarily red-light-absorbing (P... r ) and far-infrared light absorption type (P fr Two relatively stable forms of phosphorescent materials play indispensable roles in plant seed germination, de-epiphyllinization, and stem elongation. Fluorescent materials possess tunable luminescence; therefore, the development of materials that emit light similar to plant phytochrome P2+ is crucial. r and P fr Fluorescent materials that match the absorption spectrum are of great significance for plant illumination.

[0003] In luminescent materials doped with transition metal manganese ions, Mn 4+ With specific 3D 3 Electronic structure, Mn 2+ With specific 3D 5 The electronic structure makes this material highly sensitive to its surrounding environment. Manganese ions in the crystal are affected by surrounding ions or the crystal field, resulting in different luminescence phenomena. Typically, Mn... 2+ When Mn is located in an octahedral coordinated crystal field, it exhibits orange or red emission, while in a tetrahedral coordinated crystal field, it exhibits green emission. However, due to the difficulty in selecting the matrix material, the emission of Mn... 2+ Research on Mn is relatively limited, with very low doping concentrations (less than 1%) and low luminescence quantum yields. Compared to fluoride fluorescent materials, oxide fluorescent materials are more stable and easier to prepare. Therefore, finding suitable Mn... 2+ The key to this research is to activate oxide luminescent materials and improve their luminescence intensity.

[0004] Mica is a type of layered silicate, and its layers are composed of tetrahedral-octahedral-tetrahedral structural units, similar to a "sandwich" structure. The interlayers can be K... + Na + Ca2+ Or Ba 2+ Metal cations and other structural units are repeatedly stacked to form mica. Synthetic mica prepared by high-temperature solid-state methods has the characteristics of purity, insulation, strong adhesion, high transparency and good thermal stability. The most widely used is fluorophlogopite (KMg3AlSi3O4). 10 F2). However, there are currently few reports of using mica as a luminescent matrix. Summary of the Invention

[0005] To address the problem of low luminescence quantum yield in existing red fluorescent materials, this invention provides a europium-doped sodium manganese mica red luminescent material, its preparation method, and its applications. The europium-doped sodium manganese mica red luminescent material has an excitation range of 230–410 nm and significantly improved luminescence intensity. When excited by 365 nm light, its CIE chromaticity coordinates are located at (0.721, 0.279), showing great application potential in the field of deep red and far-red LEDs for plant growth.

[0006] To achieve the above objectives, the present invention provides the following technical solutions.

[0007] In a first aspect, the present invention provides a europium-doped sodium manganese mica red luminescent material with the general chemical formula NaMg. a Mn 3- a AlSi3O 10 F2:xEu 2+ , where x = 2 mol% to 5 mol%, and a = 2.4 to 2.8.

[0008] Preferably, in the general chemical formula of the europium-doped sodium manganese mica red luminescent material, x = 2.5 mol% to 4 mol%, a = 2.4 to 2.7.

[0009] It should be noted that in the chemical formula of the europium-doped sodium manganese mica red luminescent material of this invention, x refers to Eu. 2+ NaMg a Mn 3-a AlSi3O 10 The molar percentage of F2.

[0010] Compared to existing technologies, the europium-doped sodium manganese mica red luminescent material provided by this invention has a portion of Mg atoms in octahedral positions within the fluorinated phlogopite mica. 2+ Mn 2+ Replaced by Mn 2+ It appears in the matrix as an activator; however, Mn 2+ of 4 T1→ 6 The A1 transition is a forbidden transition, and its emission in the mica matrix is ​​extremely weak, almost invisible to the naked eye. This invention utilizes Eu...2+ Doping into the matrix, in Eu 2+ →Mn 2+ Under the action of energy transfer, Mn 2+ The red light emission is greatly enhanced; based on this, further through Na + interlayer cations K in manganese mica + By exchanging molecules to modulate the lattice of the mica matrix, Eu luminescence with a wider excitation range and stronger luminescence intensity can be obtained. 2+ Doped sodium manganese mica, i.e. europium-doped sodium manganese mica red luminescent material.

[0011] This invention uses sodium manganese mica as the luminescent matrix and Eu as the luminescent material. 2+ As a sensitizer, compared to existing technologies (manganese doping in other matrices), manganese in this luminescent material serves as both the luminescent center and part of the matrix, and its concentration is significantly increased. The results of the examples demonstrate that this europium-doped sodium manganese mica red luminescent material exhibits excellent performance, not only expanding the excitation range (230–410 nm) but also significantly improving the luminescence intensity. Under near-ultraviolet 365 nm excitation, the luminescence intensity is 8 times higher than that of europium-doped potassium manganese mica red luminescent material, showing great application potential in the field of deep red and far-red LEDs for plant growth.

[0012] Secondly, the present invention provides a method for preparing europium-doped sodium manganese mica red luminescent material, comprising the following steps:

[0013] Europium-doped sodium manganese mica red luminescent material was obtained by sintering Na2SiF6, MgO, Al2O3, SiO2, MnCO3 and Eu2O3 at 1000-1200℃.

[0014] The method for preparing europium-doped sodium manganese mica red luminescent material provided by this invention employs a high-temperature solid-state method, which involves removing a portion of the Mg atoms in octahedral positions from fluorophlogopite (existing technology). 2+ Use Mn 2+ Replacement, Mn 2+ It appears in the matrix as an activator; using Na + interlayer cations K in mica + Replacement is performed to modulate the lattice of the mica matrix; simultaneously, Eu... 2+ As a sensitizer, the matrix possesses excellent interlayer cation exchange capacity, Eu 2+ It is easy to penetrate the interlayer to obtain europium-doped sodium manganese mica red luminescent materials with a wider excitation range and stronger luminescence intensity.

[0015] The raw materials used in this invention are non-toxic and inexpensive, and the preparation method is simple and easy to implement. The europium-doped sodium manganese mica red luminescent material obtained has a large excitation range, strong red light emission intensity, excellent luminescence thermal stability, and high fluorescence quantum yield.

[0016] Preferably, the molar ratio of Na2SiF6, MgO, Al2O3, SiO2 and MnCO3 is 0.5:(2.4-2.8):0.5:2.5:(0.6-0.2).

[0017] Preferably, the sintering is performed using a gradient heating method with a heating rate of 3 to 7 °C / min.

[0018] Preferably, the sintering holding time is 4.5 to 6 hours.

[0019] More preferably, the sintering temperature is 1050–1150°C, and the holding time is 5–5.5 h.

[0020] For example, the raw materials are first mixed evenly by grinding, then placed in a crucible, and sintered using a tube furnace as the reaction equipment; after sintering, the mixture is cooled to room temperature and ground into powder to obtain europium-doped sodium manganese mica red luminescent material.

[0021] Thirdly, the present invention provides a phosphor-converted light-emitting diode comprising the above-mentioned europium-doped sodium manganese mica red luminescent material.

[0022] Preferably, the phosphor-converting light-emitting diode uses the europium-doped sodium manganese mica red luminescent material as the coating material for the ultraviolet chip.

[0023] The phosphor-converted light-emitting diode (pc-LED) provided by this invention has color coordinates of (0.721, 0.279), and its emission spectrum is similar to that of plant phosphors. r and P fr The absorption spectrum has a large overlap region and a high degree of matching. It can emit bright red light at a working current of 60mA, and has great application potential in the field of deep red and far red LEDs for plant growth.

[0024] Fourthly, the present invention provides a method for preparing a phosphor-converted light-emitting diode, comprising the following steps:

[0025] S1, disperse the above europium-doped sodium manganese mica red luminescent material in epoxy resin to obtain fluorescent powder;

[0026] S2, under a current of 55-65mA, the phosphor powder is coated onto the ultraviolet chip and dried to obtain a phosphor-converted light-emitting diode.

[0027] Preferably, in step S1, the volume ratio of the europium-doped sodium manganese mica red luminescent material to the epoxy resin is 1:(0.8-1.2).

[0028] Preferably, in step S2, the ultraviolet chip is a 365nm chip.

[0029] For example, in step S2, the coating thickness is 0.5 to 0.8 mm.

[0030] Fifthly, the present invention provides the application of the above-mentioned phosphor-converted light-emitting diode in plant cultivation. Attached Figure Description

[0031] Figure 1 The XRD spectra of europium-doped sodium manganese mica red luminescent materials in Examples 1, 3-5 and sodium manganese mica material in Comparative Example 1 are shown.

[0032] Figure 2 KMg for Comparative Example 2 2.5 Mn 0.5 AlSi3O 10 F2: 3 mol% Eu 2+ Compared with NaMg in Example 1 2.5 Mn 0.5 AlSi3O 10 F2: 3 mol% Eu 2+ XRD patterns;

[0033] Figure 3 NaMg for Comparative Example 1 2.5 Mn 0.5 AlSi3O 10 SEM image of F2;

[0034] Figure 4 NaMg as in Example 1 2.5 Mn 0.5 AlSi3O 10 F2: 3 mol% Eu 2+ SEM image;

[0035] Figure 5 The excitation spectra of europium-doped sodium manganese mica red luminescent materials in Examples 1, 3-5 and sodium manganese mica material in Comparative Example 1 are shown.

[0036] Figure 6 The emission spectra of europium-doped sodium manganese mica red luminescent materials in Examples 1, 3-5 and sodium manganese mica material in Comparative Example 1 are shown.

[0037] Figure 7 NaMg as in Example 1 2.5 Mn 0.5 AlSi3O 10F2: 3 mol% Eu 2+ Comparative Example 2 KMg 2.5 Mn 0.5 AlSi3O 10 F2: 3 mol% Eu 2+ Comparative Example 4 NaMg 2.5 Mn 0.5 AlSi3O 10 F2: 3 mol% Ce 3+ And NaMg in Comparative Example 5 2.5 Mn 0.5 AlSi3O 10 F2: 3mol% Bi 3+ Emission spectrum under 365nm excitation;

[0038] Figure 8 KMg for Comparative Example 2 2.5 Mn 0.5 AlSi3O 10 F2: 3 mol% Eu 2+ Compared with NaMg in Example 1 2.5 Mn 0.5 AlSi3O 10 F2: 3 mol% Eu 2+ The excitation spectrum;

[0039] Figure 9 The emission spectra of europium-doped sodium manganese mica red luminescent materials in Examples 1-2 and Comparative Example 3 are shown.

[0040] Figure 10 NaMg as in Example 1 2.5 Mn 0.5 AlSi3O 10 F2: 3 mol% Eu 2+ Temperature-dependent emission spectrum;

[0041] Figure 11 NaMg as in Example 1 2.5 Mn 0.5 AlSi3O 10 F2: 3 mol% Eu 2+ Temperature-dependent line graph of relative fluorescence intensity;

[0042] Figure 12 The CIE coordinate diagram of the pc-LED in Experiment Example 1;

[0043] Figure 13 This is a comparison of the emission spectrum of the pc-LED in Experiment Example 1 with the absorption spectra of the plant phytochromes Pr and Pfr.

[0044] Figure 14The emission spectrum of the pc-LED in Experiment Example 1 under a current drive of 60mA is shown. Detailed Implementation

[0045] The technical solutions in the embodiments of the present invention will be clearly and completely described below. 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.

[0046] Example 1

[0047] This embodiment provides a europium-doped sodium manganese mica red luminescent material NaMg. 2.5 Mn 0.5 AlSi3O 10 F2: 3 mol% Eu 2+ .

[0048] The preparation method of the above-mentioned europium-doped sodium manganese mica red luminescent material includes the following steps:

[0049] 0.5 mmol of Na₂SiF₆, 2.5 mmol of MgO, 0.5 mmol of Al₂O₃, 2.5 mmol of SiO₂, 0.5 mmol of MnCO₃, and 0.015 mmol of Eu₂O₃ were ground and mixed evenly in an agate mortar. The mixture was then poured into a corundum crucible, covered, and sintered at 1100 °C at a heating rate of 5 °C / min using a tube furnace as the reaction equipment. The temperature was increased to 1100 °C and held for 5.5 h. After sintering, the mixture was cooled to room temperature and ground into powder to obtain europium-doped sodium manganese mica red luminescent material. The chemical reaction formula for the synthesis of sodium manganese mica (matrix) is as follows.

[0050] 0.5Na2SiF6+2.5MgO+0.5Al2O3+2.5SiO2+0.5MnCO3→NaMg 2.5 Mn 0.5 AlSi3O 10 F2

[0051] Example 2

[0052] This embodiment provides a europium-doped sodium manganese mica red luminescent material NaMg. 2.75 Mn 0.25 AlSi3O 10 F2: 3 mol% Eu 2+ .

[0053] The preparation method of the above-mentioned europium-doped sodium manganese mica red luminescent material includes the following steps:

[0054] 0.5 mmol of Na₂SiF₆, 2.75 mmol of MgO, 0.5 mmol of Al₂O₃, 2.5 mmol of SiO₂, 0.25 mmol of MnCO₃, and 0.015 mmol of Eu₂O₃ were ground in an agate mortar and mixed thoroughly. The mixture was then poured into a corundum crucible, covered, and sintered at 1150 °C at a heating rate of 4 °C / min using a tube furnace as the reaction equipment. The temperature was raised to 1150 °C and held for 5 h. After sintering, the mixture was cooled to room temperature and ground into powder to obtain europium-doped sodium manganese mica red luminescent material. The chemical reaction formula for the synthesis of sodium manganese mica (matrix) is as follows.

[0055] 0.5Na2SiF6+2.75MgO+0.5Al2O3+2.5SiO2+0.25MnCO3→NaMg 2.75 Mn 0.25 AlSi3O 10 F2

[0056] Example 3

[0057] This embodiment provides a europium-doped sodium manganese mica red luminescent material NaMg. 2.5 Mn 0.5 AlSi3O 10 F2: 2 mol% Eu 2+ .

[0058] The preparation method of the above-mentioned europium-doped sodium manganese mica red luminescent material includes the following steps:

[0059] 0.5 mmol of Na₂SiF₆, 2.5 mmol of MgO, 0.5 mmol of Al₂O₃, 2.5 mmol of SiO₂, 0.5 mmol of MnCO₃, and 0.01 mmol of Eu₂O₃ were ground in an agate mortar and mixed thoroughly. The mixture was then poured into a corundum crucible, covered, and sintered at 1000 °C using a tube furnace at a heating rate of 3 °C / min for 6 hours. After sintering, the mixture was cooled to room temperature and ground into powder to obtain europium-doped sodium manganese mica red luminescent material. The chemical reaction formula for the synthesis of sodium manganese mica (matrix) is shown in Example 1.

[0060] Example 4

[0061] This embodiment provides a europium-doped sodium manganese mica red luminescent material NaMg. 2.5 Mn 0.5 AlSi3O 10 F2: 4 mol% Eu 2+ .

[0062] The preparation method of the above-mentioned europium-doped sodium manganese mica red luminescent material includes the following steps:

[0063] 0.5 mmol of Na₂SiF₆, 2.5 mmol of MgO, 0.5 mmol of Al₂O₃, 2.5 mmol of SiO₂, 0.5 mmol of MnCO₃, and 0.02 mmol of Eu₂O₃ were ground in an agate mortar and mixed thoroughly. The mixture was then poured into a corundum crucible, covered, and sintered at 1050 °C at a heating rate of 6 °C / min using a tube furnace as the reaction equipment. The temperature was increased to 1050 °C and held for 5.5 h. After sintering, the mixture was cooled to room temperature and ground into powder to obtain europium-doped sodium manganese mica red luminescent material. The chemical reaction formula for the synthesis of sodium manganese mica (matrix) is shown in Example 1.

[0064] Example 5

[0065] This embodiment provides a europium-doped sodium manganese mica red luminescent material NaMg. 2.5 Mn 0.5 AlSi3O 10 F2: 5 mol% Eu 2+ .

[0066] The preparation method of the above-mentioned europium-doped sodium manganese mica red luminescent material includes the following steps:

[0067] 0.5 mmol of Na₂SiF₆, 2.5 mmol of MgO, 0.5 mmol of Al₂O₃, 2.5 mmol of SiO₂, 0.5 mmol of MnCO₃, and 0.025 mmol of Eu₂O₃ were ground in an agate mortar and mixed thoroughly. The mixture was then poured into a corundum crucible, covered, and sintered at 1200 °C at a heating rate of 7 °C / min using a tube furnace as the reaction equipment. The temperature was increased to 1200 °C and held for 4.5 h. After sintering, the mixture was cooled to room temperature and ground into powder to obtain europium-doped sodium manganese mica red luminescent material. The chemical reaction formula for the synthesis of sodium manganese mica (matrix) is shown in Example 1.

[0068] Comparative Example 1

[0069] This comparative example provides a sodium manganese mica material NaMg 2.5 Mn 0.5 AlSi3O 10 F2.

[0070] The preparation method of the sodium manganese mica material described above is similar to that in Example 1, except that Eu2O3 is not added to the raw materials. All other conditions remain unchanged and will not be repeated here. The chemical reaction formula for the synthesis of the sodium manganese mica material is shown in Example 1.

[0071] Comparative Example 2

[0072] This comparative example provides a europium-doped manganese mica red luminescent material KMg 2.5 Mn 0.5AlSi3O 10 F2: 3 mol% Eu 2 + .

[0073] The preparation method of the europium-doped manganese mica red luminescent material described above is similar to that in Example 1, except that Na2SiF6 is replaced with an equal molar amount of K2SiF6, while the other conditions remain unchanged and will not be described again. The chemical reaction formula for the synthesis of manganese mica (matrix) is shown below.

[0074] 0.5K2SiF6+2.5MgO+0.5Al2O3+2.5SiO2+0.5MnCO3→KMg 2.5 Mn 0.5 AlSi3O 10 F2

[0075] Comparative Example 3

[0076] This comparative example provides a europium-doped sodium manganese mica red luminescent material NaMg. 2.25 Mn 0.75 AlSi3O 10 F2: 3 mol% Eu 2+ .

[0077] The preparation method of the europium-doped sodium manganese mica red luminescent material is similar to that in Example 1, except that the molar amounts of MgO and MnCO3 are replaced with 2.25 mmol and 0.75 mmol, respectively. All other conditions remain unchanged and will not be described further. The chemical reaction formula for the synthesis of sodium manganese mica (matrix) is shown below.

[0078] 0.5Na2SiF6+2.25MgO+0.5Al2O3+2.5SiO2+0.75MnCO3→NaMg 2.75 Mn 0.25 AlSi3O 10 F2

[0079] Comparative Example 4

[0080] This comparative example provides a cerium-doped sodium manganese mica red luminescent material NaMg 2.5 Mn 0.5 AlSi3O 10 F2: 3 mol% Ce 3+ .

[0081] The preparation method of the cerium-doped sodium manganese mica red luminescent material is similar to that in Example 1, except that 0.015 mmol of Eu2O3 is replaced with 0.03 mmol of CeO2, and the other conditions remain unchanged, which will not be described in detail here.

[0082] Comparative Example 5

[0083] This comparative example provides a bismuth-doped sodium manganese mica red luminescent material NaMg 2.5 Mn 0.5 AlSi3O 10 F2: 3mol% Bi 3+ .

[0084] The preparation method of the above-mentioned bismuth-doped sodium manganese mica red luminescent material is similar to that in Example 1, except that Eu2O3 is replaced with an equal molar amount of Bi2O3, and the other conditions remain unchanged, which will not be described again.

[0085] Experimental Example 1

[0086] This embodiment provides a phosphor-converted light-emitting diode (pc-LED) using the europium-doped sodium manganese mica red luminescent material NaMg from Example 1. 2.5 Mn 0.5 AlSi3O 10 F2: 3 mol% Eu 2+ The coating material used for ultraviolet chips specifically includes the following steps:

[0087] S1, disperse the europium-doped sodium manganese mica red luminescent material of Example 1 in epoxy resin (the volume ratio of europium-doped sodium manganese mica red luminescent material to epoxy resin is 1:1) to obtain fluorescent powder.

[0088] S2, the above phosphor powder is coated onto a 365nm chip under a current of 60mA and dried to obtain a pc-LED.

[0089] Performance testing

[0090] To further illustrate the performance of the europium-doped sodium manganese mica red luminescent material provided by the present invention, the present invention conducted relevant optical tests on the composite materials of Examples 1-5 and Comparative Examples 1-5 and the pc-LED of Experimental Example 1.

[0091] 1. XRD test

[0092] The present invention performs XRD tests on the europium-doped sodium manganese mica red luminescent materials of Examples 1, 3-5 and the sodium manganese mica material of Comparative Example 1. The results are as follows: Figure 1 As shown in the figure, the positions and shapes of the diffraction peaks of the europium-doped sodium manganese mica red luminescent materials in Examples 1, 3-5 are very similar, indicating the structural similarity of the europium-doped sodium manganese mica red luminescent materials provided by this invention. Furthermore, compared with undoped Eu... 2+ Compared to sodium manganese mica materials, Eu 2+ The europium-doped sodium manganese mica red luminescent material did not exhibit any additional impurity phases, indicating that a small amount of Eu... 2+The doping has little effect on the structure of the mica matrix. The diffraction peaks of the above materials at 9.1°, 19.4°, 27.1°, 34.3° and 45.9° (2θ) correspond to the (001), (020), (003), (200) and (005) crystal planes, respectively. Among them, the diffraction angles corresponding to the (001), (003) and (005) crystal planes show a good multiple relationship, which indicates that the europium-doped sodium manganese mica red luminescent material provided by the present invention has a layered structure.

[0093] This invention relates to KMg in Comparative Example 2 2.5 Mn 0.5 AlSi3O 10 F2: 3 mol% Eu 2+ Compared with NaMg in Example 1 2.5 Mn 0.5 AlSi3O 10 F2: 3 mol% Eu 2+ XRD testing was performed, and the results are as follows: Figure 2 As shown in the figure. It can be seen from the figure that the interlayer cations of the matrix, regardless of whether they are K... + Or Na + All exhibit three diffraction peaks on the (001), (003), and (005) crystal planes, indicating a good layered structure. Compared to KMg in Comparative Example 2... 2.5 Mn 0.5 AlSi3O 10 F2: 3 mol% Eu 2+ NaMg in Example 1 2.5 Mn 0.5 AlSi3O 10 F2: 3 mol% Eu 2+ The 2θ angles corresponding to the diffraction peaks of the (001), (003), and (005) crystal planes shift towards higher angles. According to Bragg's equation, the KMg in Comparative Example 2 can be calculated to... 2.5 Mn 0.5 AlSi3O 10 F2: 3 mol% Eu 2+ The interlayer spacing is NaMg in Example 1 2.5 Mn 0.5 AlSi3O 10 F2: 3 mol% Eu 2+ The interlayer spacing is reduced to Because of Na + ( The ionic radius of CN=12 is smaller than that of K. + ( CN=12), using Na + Replace K + Subsequently, the interlayer spacing of the matrix decreases.

[0094] 2. Scanning electron microscopy test

[0095] This invention relates to NaMg in Comparative Example 1. 2.5 Mn 0.5 AlSi3O 10 F2 and NaMg from Example 1 2.5 Mn 0.5 AlSi3O 10 F2: 3 mol% Eu 2+ Scanning electron microscopy (SEM) tests were performed, and the results are as follows: Figures 3-4 As shown in the figure, both exhibit a layered structure and good crystallization, consistent with the results of XRD testing.

[0096] 3. Fluorescence spectroscopy test

[0097] This invention applies to different Eu 2+ Fluorescence spectra of europium-doped sodium manganese mica red luminescent materials (Examples 1, 3-5 and Comparative Example 1) were measured, and the results are as follows: Figures 5-6 As shown in the figure, the excitation and emission peaks of the europium-doped sodium manganese mica red luminescent materials in Examples 1 and 3-5 all exhibit a series of similar shapes. 2+ The critical doping concentration is 3 mol%.

[0098] Excitation spectrum ( Figure 5 Under 716 nm monitoring, the europium-doped sodium manganese mica red luminescent materials of Examples 1 and 3-5 exhibit an ultra-wide absorption band in the 230-410 nm range, especially showing strong luminescence under ultraviolet light excitation in the 250-380 nm range. This is mainly attributed to Eu... 2+ 4f 7 →4f 6 5d 1 Transition, similar to Eu 2+ In sodium mica (NaMg3AlSi3O) 10 Excitation in F2). Since the europium-doped sodium manganese mica red luminescent materials of Examples 1 and 3-5 have a particularly prominent excitation band near 317 nm, 317 nm was chosen as the excitation wavelength.

[0099] Emission spectrum ( Figure 6 The excitation wavelength was 317 nm, and the spectrum showed two broadband emission bands at 380–480 nm and 620–860 nm, with the main peaks at 418 nm and 716 nm, respectively, which are attributed to Eu. 2+ 4f 6 5d 1 →4f 7 (8 S 7 / 2 ) transition and Mn 2+ of 4 T1( 4 G)→ 6 A1( 6 S) transition. Due to the tetrahedral coordination of Mn 2+ Occupying cation sites typically emits green emission; octahedral coordinated Mn 2+ It then emits a red emission, and in this invention, Mn 2+ The emission peak is located after 700 nm, and the full width at half maximum (FWHM) is approximately 106 nm, exhibiting excellent red emission performance. Therefore, in this invention, Mn... 2+ The red emission indicates that it occupies the octahedral sites of the multilayered network in the matrix.

[0100] The present invention relates to NaMg in Example 1 2.5 Mn 0.5 AlSi3O 10 F2: 3 mol% Eu 2+ Comparative Example 2 KMg 2.5 Mn 0.5 AlSi3O 10 F2: 3 mol% Eu 2+ Comparative Example 4 NaMg 2.5 Mn 0.5 AlSi3O 10 F2: 3 mol% Ce 3+ And NaMg in Comparative Example 5 2.5 Mn 0.5 AlSi3O 10 F2: 3mol% Bi 3+ Fluorescence spectroscopy tests were performed, and the results are as follows: Figure 7 As shown in the figure. It can be seen from the figure that the NaMg in Example 1... 2.5 Mn 0.5 AlSi3O 10 F2: 3 mol% Eu 2+ The relative fluorescence intensity of KMg in Comparative Example 2 2.5 Mn 0.5 AlSi3O 10 F2: 3 mol% Eu 2+ 8 times; sensitizer Eu 2+ It can greatly promote the growth of Mn in the matrix 2+ The luminescence of Ce 3+ Bi 3+ The sensitization effects were not ideal.

[0101] This invention relates to KMg in Comparative Example 2 2.5 Mn 0.5 AlSi3O10 F2: 3 mol% Eu 2+ Compared with NaMg in Example 1 2.5 Mn 0.5 AlSi3O 10 F2: 3 mol% Eu 2+ Fluorescence spectroscopy was performed, and the results are as follows: Figure 8 As shown in the figure. It can be seen from the figure that the NaMg in Example 1... 2.5 Mn 0.5 AlSi3O 10 F2: 3 mol% Eu 2+ The wider excitation band indicates that the europium-doped sodium manganese mica red luminescent material provided by this invention can be effectively excited by near-ultraviolet light, which is beneficial for its application in the field of plant lighting.

[0102] Figures 7-8 The results show that structural modification can adjust the lattice environment of mica crystals to affect the Mn content. 2+ It makes a significant contribution to the enhancement of light emission.

[0103] This invention applies to different Mn 2+ Fluorescence spectra of europium-doped sodium manganese mica red luminescent materials (Examples 1-2 and Comparative Example 3) were measured, and the results are as follows: Figure 9 As shown in the figure, the spectrum consists of two broadband bands: 380–480 nm and 620–860 nm, which belong to Eu. 2+ 4f 6 5d 1 →4f transition and Mn 2+ of 4 T1→ 6 A1( 6 S) transition. The results show that as Mn... 2+ With increasing doping concentration, Mn 2+ The intensity of red light emission gradually increases, while Eu 2+ The emission intensity gradually decreased, which verifies the presence of Eu in the sodium manganese mica matrix. 2+ →Mn 2+ Energy transfer. Furthermore, Mn 2+ The optimal concentration is 0.5, and further increases in concentration are due to the low concentration of Mn. 2+ -Mn 2+ The concentration quenching phenomenon occurs, and the red light emission intensity of europium-doped sodium manganese mica red luminescent material will be greatly reduced.

[0104] 4. Fluorescence quantum yield test

[0105] Using BaSO4 as a reference, this invention tested the NaMg of Example 1 under 317 nm excitation. 2.5 Mn0.5 AlSi3O 10 F2: 3 mol% Eu 2+ The quantum yield of NaMg. The results show that NaMg 2.5 Mn 0.5 AlSi3O 10 F2: 3 mol% Eu 2+ It has a high quantum yield of 87.37%.

[0106] 5. Fluorescence lifetime test

[0107] The fluorescence lifetime of the europium-doped sodium manganese mica red luminescent materials of Examples 1-5 was tested, and the results are shown in Table 1.

[0108] Table 1. Fluorescence lifetime of europium-doped sodium manganese mica red luminescent materials in Examples 1-5

[0109] Europium-doped sodium manganese mica red luminescent material Fluorescence lifetime τ (ms) Example 1 5.63 Example 2 3.87 Example 3 2.23 Example 4 4.09 Example 5 1.15

[0110] 6. Temperature resistance test

[0111] The present invention relates to NaMg in Example 1 2.5 Mn 0.5 AlSi3O 10 F2: 3 mol% Eu 2+ Temperature resistance tests were conducted, and the results are as follows: Figures 10-11 As shown. From Figure 10 As can be seen from this, Mn 2+ The emission wavelength exhibits a slight blue shift, with peak positions of 716 nm and 690 nm at 303 K and 563 K, respectively. This can be observed in Mn... 2+ This can be explained by thermally active phonon-assisted excitation from low-energy sublevels to high-energy sublevels in the excited state. Due to the thermal quenching effect, Figure 11 This more intuitively demonstrates that the luminescence intensity of the europium-doped sodium manganese mica red luminescent material gradually decreases with increasing temperature. However, overall, the europium-doped sodium manganese mica red luminescent material provided by this invention exhibits good thermal stability; when the temperature rises to 423K (150℃, higher than the operating temperature of PC-LEDs), the NaMg... 2.5 Mn 0.5 AlSi3O 10 F2: 3 mol% Eu 2+ The luminescence intensity can still reach 78% of that at room temperature (298K).

[0112] 7. Application Testing

[0113] Figure 12The figure shows the CIE color coordinates of the pc-LED in Experimental Example 1. As can be seen from the figure, when excited by 365nm light, the color coordinates are (0.721, 0.279), indicating that the europium-doped sodium manganese mica red luminescent material provided by this invention has great application potential in the field of deep red and far-red LEDs for plant growth.

[0114] To further evaluate the performance of the pc-LED in Experimental Example 1 in practical applications, the emission spectrum of the pc-LED device in Experimental Example 1 was compared with that of the plant photosensitive pigment P. r and P fr The absorption spectra were compared, and the results are as follows: Figure 13 As shown in the figure. It can be seen from the figure that the emission spectrum of the pc-LED provided by this invention is similar to that of plant P. r and P fr The absorption spectra of the two materials have a large overlapping region and a high degree of matching. This indicates that the europium-doped sodium manganese mica red luminescent material provided by this invention can be effectively applied to the preparation of far-red PC-LEDs, and further used for indoor plant cultivation.

[0115] The present invention also conducted emission spectrum tests on the pc-LED of Experimental Example 1, and the results are as follows: Figure 14 As shown in the figure. It can be seen from the figure that under 365nm ultraviolet chip excitation, NaMg... 2.5 Mn 0.5 AlSi3O 10 F2: 3 mol% Eu 2+ The presence of a far-red emission band near 716 nm indicates that the electroluminescence and photoluminescence of the europium-doped sodium manganese mica red luminescent material provided by this invention are the same. Digital photography of the PC-LED revealed that it emits bright red light at a working current of 60 mA.

[0116] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions or improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A europium-doped sodium manganese mica red luminescent material, characterized in that, The general chemical formula is NaMg a Mn 3-a AlSi3O 10 F2:xEu 2+ ; Where x = 2 mol%~5 mol%, a = 2.4~2.75; Mn 2+ As an activator, Eu 2+ It is a sensitizer.

2. The europium-doped sodium manganese mica red luminescent material as described in claim 1, characterized in that, In the general chemical formula of the europium-doped sodium manganese mica red luminescent material, x = 2.5 mol%~4 mol%, a = 2.4~2.

7.

3. A method for preparing the europium-doped sodium manganese mica red luminescent material according to claim 1 or 2, characterized in that, Includes the following steps: Europium-doped sodium manganese mica red luminescent material was obtained by sintering Na2SiF6, MgO, Al2O3, SiO2, MnCO3 and Eu2O3 at 1000~1200℃.

4. The preparation method of europium-doped sodium manganese mica red luminescent material as described in claim 3, characterized in that, The molar ratio of Na2SiF6, MgO, Al2O3, SiO2 and MnCO3 is 0.5:(2.4~2.8):0.5:2.5:(0.6~0.25).

5. The method for preparing europium-doped sodium manganese mica red luminescent material as described in claim 3, characterized in that, The sintering process employs a gradient heating method with a heating rate of 3~7℃ / min.

6. The method for preparing europium-doped sodium manganese mica red luminescent material as described in claim 3, characterized in that, The holding time for sintering is 4.5 to 6 hours.

7. A phosphor-converting light-emitting diode, comprising europium-doped sodium manganese mica red luminescent material as described in claim 1 or 2, or europium-doped sodium manganese mica red luminescent material prepared by the preparation method of europium-doped sodium manganese mica red luminescent material as described in any one of claims 3 to 6.

8. A method for preparing the phosphor-converting light-emitting diode according to claim 7, comprising the following steps: S1, disperse the europium-doped sodium manganese mica red luminescent material in epoxy resin to obtain fluorescent powder; S2, under a current of 55~65mA, the phosphor powder is coated onto the ultraviolet chip and dried to obtain a phosphor-converted light-emitting diode.

9. The method for preparing a phosphor-converted light-emitting diode as described in claim 8, characterized in that, In step S1, the volume ratio of the europium-doped sodium manganese mica red luminescent material to the epoxy resin is 1:(0.8~1.2).

10. The application of the phosphor-converting light-emitting diode according to claim 7 or the phosphor-converting light-emitting diode prepared by the preparation method of the phosphor-converting light-emitting diode according to claim 8 or 9 in plant cultivation.

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