Preparation method and application of europium and terbium double-doped fluorapatite fluorescent powder

Abstract

The invention relates to the technical field of preparation of fluorapatite structure fluorescent powder, in particular to europium and terbium double-doped fluorapatite fluorescent powder as well as a preparation method and application thereof. The preparation method comprises the following steps: dissolving soluble strontium salt, soluble terbium salt, soluble europium salt, NH4H2PO4 and N2H4H2O into water together to obtain a mixed solution; and adding soluble hexafluorophosphate into the mixed solution, carrying out coprecipitation reaction, washing and centrifuging to obtain the europium and terbium double-doped fluorapatite fluorescent powder. The preparation method disclosed by the invention is simple and efficient, realizes reaction under the condition of room temperature, remarkably shortens the reaction time, reduces the energy consumption, realizes green synthesis of the fluorapatite fluorescent powder, and effectively overcomes the defects of a traditional high-temperature solid-phase method and a hydrothermal reaction method.

Description

Technical Field

[0001] The present invention relates to the technical field of preparation of fluorapatite structured phosphors, and in particular to europium and terbium dual-doped fluorapatite phosphors, a preparation method thereof, and applications thereof. Background Art

[0002] Rare earth doped fluoroapatite phosphors have attracted much attention in the field of luminescent materials research in recent years due to their unique optical properties and adjustable structural advantages. Sr5(PO4)3F (SPF), as a fluorine-containing phosphate mineral, belongs to the apatite structure family. Its crystal structure is similar to that of hydroxyapatite (Ca5(PO4)3OH). 2+ ) replaces calcium (Ca 2+ ), fluoride ion (F - ) substituted hydroxyl group (OH - ). This material has a large crystal field, a large emission and absorption cross section, and excellent chemical and thermal stability, making it an excellent matrix for luminescent and laser materials. The key to optimizing the luminescent properties of such phosphors lies in the fine control of their nanostructure, phase state and morphology. An important challenge in the current research field is to develop a green and low-carbon preparation process to achieve the synthesis of morphology-controllable luminescent materials. Ionic liquids have attracted attention due to their low toxicity, green environmental protection and high thermal stability. In the synthesis of inorganic materials, ionic liquids can be used as fluorine sources, templates and solvents at the same time, thereby more effectively controlling the morphology and size of the products. Therefore, it is of great significance to explore the green synthesis method of this material using ionic liquids to assist in the rapid synthesis of Sr5(PO4)3F at room temperature.

[0003] Currently, among rare earth ion doped luminescent materials, Eu 3+ and Tb 3+ They are commonly used to achieve orange-red and green luminescence respectively. Under ultraviolet light excitation, Eu 3+ Occurrence from 5 D0- 7 F J (J=1, 2, 3, 4) energy level transition, the main emission peak is in the red region. 3+ Then it happens 5 D4- 7 F J (J=6, 5, 4, 3) energy level transition, the main emission peak is in the green region. 3+ Ions to Eu 3 + The energy transfer of ions can significantly enhance the 3+ The fluorescence intensity of the ions can be adjusted to achieve the regulation of the luminescence color.

[0004] Currently, the reported Sr5(PO4)3F:Eu 3+ / Tb3+ Apatite phosphors are primarily prepared by high-temperature solid-phase methods and hydrothermal reaction methods. These methods are often time-consuming (typically 1 to 3 hours for the high-temperature solid-phase method and 24 hours for the hydrothermal reaction method), energy-intensive, and potentially environmentally polluting. Summary of the Invention

[0005] In response to the shortcomings of the existing technology, the present invention provides a europium and terbium co-doped fluorapatite phosphor, as well as its preparation method and application. The present invention uses a soluble strontium salt, a soluble terbium salt, a soluble europium salt, NH4H2PO4, and N2H4•H2O as raw materials, dissolves them in water, and then adds a fluorine-containing ionic liquid (soluble hexafluorophosphate) to produce the europium and terbium co-doped fluorapatite phosphor via a coprecipitation reaction. The present invention utilizes a soluble hexafluorophosphate as a template and a fluorine-containing ionic liquid, combined with a coprecipitation method, to achieve a reaction at room temperature, significantly shortening the reaction time and reducing energy consumption. The preparation method of the present invention achieves green synthesis of fluorapatite phosphor, effectively overcoming the shortcomings of traditional high-temperature solid-phase methods and hydrothermal reaction methods.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is: The first object of the present invention is to provide a method for preparing the above-mentioned europium and terbium dual-doped fluorapatite phosphor, comprising the following steps: Soluble strontium salt, soluble terbium salt, soluble europium salt, NH4H2PO4 and N2H4•H2O are dissolved in water to obtain a mixed solution; soluble hexafluorophosphate is added to the mixed solution to carry out a coprecipitation reaction. During the coprecipitation reaction, PF6 − Hydrolyzes and generates PO4 3- and F - , while the Sr in the mixed solution 2+ With PO4 3- and F - Combined to form Sr5(PO4)3F fluoroapatite structure, while Tb 3+ and Eu 3+ By replacing part of Sr 2+ Entering the lattice of Sr5(PO4)3F, europium and terbium double-doped fluoroapatite phosphor is obtained. − +4H2O→H3PO4+5HF+F - , Sr 2+ +PO4 3- +F - →Sr5(PO4)3F;PF6 − Can hydrolyze PO4 3- , while other ions hydrolyzed by other fluorinated ionic liquids will affect the results.

[0007] The coprecipitation reaction conditions are: stirring the reaction at room temperature for 20 minutes to 30 minutes.

[0008] Preferably, in the mixed solution, Sr 2+ , Tb 3+ 、Eu 3+ 、H2PO4 - The molar ratio of Sr to N2H4•H2O is 5:0.01~0.10:0.02~0.1:3:1; more preferably, in the mixed solution, Sr 2+ , Tb 3+ 、Eu 3+ 、H2PO4 - The molar ratio of N2H4•H2O is 5:0.08:0.1:3:1 Preferably, PF6 in soluble hexafluorophosphate − With Sr 2+ The molar ratio is 2:4.9~5.3, more preferably, PF6 in soluble hexafluorophosphate − With Sr 2+ The molar ratio is 2:5.

[0009] Preferably, the soluble hexafluorophosphate is selected from 1-octyl-3-methylimidazolium hexafluorophosphate, 1-butyl-3-methylimidazolium hexafluorophosphate or 1-ethyl-3-methylimidazolium hexafluorophosphate.

[0010] The second object of the present invention is to provide europium and terbium dual-doped fluorapatite phosphor prepared by the above preparation method.

[0011] Preferably, the crystal structure of the europium and terbium doped fluorapatite phosphor is a hexagonal fluorapatite structure.

[0012] Preferably, the europium and terbium doped fluoroapatite phosphor has a nanorod structure.

[0013] The third object of the present invention is to provide the use of the above-mentioned europium and terbium doped fluoroapatite phosphor in the preparation of fluorescent sensors or optoelectronic devices.

[0014] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention provides a method for preparing europium and terbium doped fluoroapatite phosphor, comprising dissolving a soluble strontium salt, a soluble terbium salt, a soluble europium salt, NH4H2PO4 and N2H4•H2O in water to obtain a mixed solution; adding a soluble hexafluorophosphate to the mixed solution to perform a coprecipitation reaction; during the coprecipitation reaction, PF6 − Hydrolyzes and generates PO4 3- and F - , while the Sr in the mixed solution 2+With PO4 3- and F - Combined to form Sr5(PO4)3F fluoroapatite structure, while Tb 3+ and Eu 3+ By replacing part of Sr 2+ The coprecipitation reaction is carried out under stirring at room temperature for 20 to 30 minutes. This method utilizes a soluble hexafluorophosphate as a template and a fluorine-containing ionic liquid, combined with coprecipitation, to achieve a room-temperature reaction, significantly shortening the reaction time and reducing energy consumption. This method also achieves a green synthesis of fluorapatite phosphor, effectively overcoming the shortcomings of traditional high-temperature solid-phase and hydrothermal reaction methods.

[0015] 2. The europium and terbium doped fluoroapatite phosphor of the present invention has the property of adjustable luminescence color. 3+ and Eu 3+ The luminous color can be continuously adjusted from green to red, and 72.42% of the initial luminous intensity is still maintained at 498K. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a flow chart for preparing europium and terbium dual-doped fluorapatite phosphors according to Examples 1 to 6 of the present invention.

[0017] Figure 2 0.08Tb in Example 1 3+ ,0.1Eu 3+ , 0.08Tb of Comparative Example 1 3+ And the 0.1Eu of Comparative Example 2 3+ XRD spectrum of .

[0018] Figure 3 0.08Tb in Example 1 3+ ,0.1Eu 3+ SEM image of .

[0019] Figure 4 These are excitation and emission spectra of the europium and terbium doped fluorapatite phosphors of Examples 1 to 6, the terbium doped fluorapatite phosphor of Comparative Example 1, and the europium doped fluorapatite phosphor of Comparative Example 2, wherein (a) is the terbium doped fluorapatite phosphor of Comparative Example 1, (b) is the europium doped fluorapatite phosphor of Comparative Example 2, and (c) is the europium and terbium doped fluorapatite phosphor of Examples 1 to 6.

[0020] Figure 5 0.08Tb in Example 1 3+ ,0.1Eu 3+ , 0.08Tb of Comparative Example 13+ And the 0.1Eu of Comparative Example 2 3+ Excitation and emission spectra of Comparative Examples 1 and 2; (a) is the emission spectra of Comparative Example 1 and Comparative Example 2, (b) is the 0.08Tb of Example 1 3+ ,0.1Eu 3+ , 0.08Tb of Comparative Example 1 3+ And the 0.1Eu of Comparative Example 2 3+ The stimulation.

[0021] Figure 6 The europium and terbium doped fluoroapatite phosphors of Examples 1 and 7 to 10 and the 0.1Eu 3+ Excitation spectrum and CIE chromaticity diagram, where (a) is the emission spectrum and (b) is the CIE chromaticity diagram.

[0022] Figure 7 0.08Tb in Example 1 3+ ,0.1Eu 3+ Schematic diagram of the energy transfer process.

[0023] Figure 8 0.08Tb in Example 1 3+ ,0.1Eu 3+ Temperature-dependent emission spectra of .

[0024] Figure 9 0.08Tb of Application Example 8 3+ ,0.04Eu 3+ and BaMgAl 10 O 17 :Eu 2+ Electroluminescence spectrum of a device assembled with commercial phosphor and LED chip driven at 30mA, where a is the actual picture of the LED device before emitting light, and b is the actual picture of the LED device after emitting light. DETAILED DESCRIPTION

[0025] The following will clearly and completely describe the technical solution of the present invention in conjunction with the data in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0026] It should be noted that the professional terms used in the present invention are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention. Unless otherwise specified, the various raw materials, reagents, instruments and equipment used in the following embodiments of the present invention can be purchased from the market or prepared by existing methods. Among them, 1-octyl-3-methylimidazolium hexafluorophosphate is denoted as [Omim]PF6.

[0027] In the prior art, the reported Sr5(PO4)3F:Eu 3+ / Tb 3+ Apatite phosphors are primarily prepared by high-temperature solid-phase methods and hydrothermal reaction methods. These methods are often time-consuming (typically 1 to 3 hours for the high-temperature solid-phase method and 24 hours for the hydrothermal reaction method), energy-intensive, and potentially environmentally polluting.

[0028] In order to solve the problems of time-consuming, high energy consumption and potential environmental pollution in the existing preparation methods, the present invention uses soluble strontium salt, soluble terbium salt, soluble europium salt, NH4H2PO4 and N2H4•H2O as raw materials, dissolves them in water, adds fluorine-containing ionic liquid (soluble hexafluorophosphate), uses soluble hexafluorophosphate as a template and fluorine-containing ionic liquid, combines coprecipitation method, and reacts at room temperature to make PF6 in soluble hexafluorophosphate - Hydrolyzes and generates PO4 3- and F - , while the Sr in the mixed solution 2+ With PO4 3- and F - Combined to form Sr5(PO4)3F fluoroapatite structure, while Tb 3+ and Eu 3+ By replacing part of Sr 2+ It enters the crystal lattice of Sr5(PO4)3F to obtain europium and terbium dual-doped fluoroapatite phosphor; the conditions of the co-precipitation reaction are: stirring the reaction at room temperature for 20min~30min, which significantly shortens the reaction time and reduces energy consumption, realizes the green synthesis of fluoroapatite phosphor, and effectively overcomes the defects of traditional high-temperature solid-phase method and hydrothermal reaction method.

[0029] In order to enable those skilled in the art to more clearly understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments: Example 1 A method for preparing europium and terbium doped fluorapatite phosphor comprises the following steps: S1. Dissolve 4.55 mmol of SrCl2, 0.4 mmol of Tb(NO3)3, 0.5 mmol of Eu(NO3)3 and 3 mmol of NH4H2PO4 in 25 mL of water, add 3 mL of N2H4•H2O, and stir magnetically at room temperature for 10 min to obtain a mixed solution.

[0030] S2. Add 1 mmol of [Omim]PF6 to the mixed solution and stir the mixture at room temperature for 20 minutes to generate a precipitate. The precipitate is then washed with deionized water and ethanol in sequence. After washing, the precipitate is placed in an oven and dried at 60°C for 12 hours to obtain europium and terbium doped fluoroapatite phosphor, which is recorded as Sr5(PO4)3F:Tb 3+ ,Eu 3+ Phosphor, abbreviated as 0.08Tb 3+ ,0.1Eu 3+ .

[0031] Example 2 A preparation method of europium and terbium doped fluorapatite phosphor is the same as the preparation method of Example 1, except that Tb 3+ With Eu 3+ The molar ratio is replaced by 0.08:0.1 to 0.06:0.1, comprising the following steps: S1. Dissolve 4.55 mmol of SrCl2, 0.3 mmol of Tb(NO3)3, 0.5 mmol of Eu(NO3)3 and 3 mmol of NH4H2PO4 in 25 mL of water, add 3 mL of N2H4•H2O, and stir magnetically at room temperature for 10 min to obtain a mixed solution.

[0032] S2. Add 1 mmol of [Omim]PF6 to the mixed solution and stir the mixture at room temperature for 20 minutes to generate a precipitate. The precipitate is then washed with deionized water and ethanol in sequence. After washing, the precipitate is placed in an oven and dried at 60°C for 12 hours to obtain europium and terbium doped fluoroapatite phosphor, which is recorded as Sr5(PO4)3F:Tb 3+ ,Eu 3+ Phosphor, abbreviated as 0.06Tb 3+ ,0.1Eu 3+ .

[0033] Example 3 A preparation method of europium and terbium doped fluorapatite phosphor is the same as the preparation method of Example 1, except that Tb 3+ With Eu 3+ The molar ratio is replaced by 0.08:0.1 to 0.04:0.1, comprising the following steps: S1. Dissolve 4.55 mmol of SrCl2, 0.2 mmol of Tb(NO3)3, 0.5 mmol of Eu(NO3)3 and 3 mmol of NH4H2PO4 in 25 mL of water, add 3 mL of N2H4•H2O, and stir magnetically at room temperature for 10 min to obtain a mixed solution.

[0034] S2. Add 1 mmol of [Omim]PF6 to the mixed solution and stir the mixture at room temperature for 20 minutes to generate a precipitate. The precipitate is then washed with deionized water and ethanol in sequence. After washing, the precipitate is placed in an oven and dried at 60°C for 12 hours to obtain europium and terbium doped fluoroapatite phosphor, which is recorded as Sr5(PO4)3F:Tb 3+ ,Eu 3+ Phosphor, abbreviated as 0.04Tb 3+ ,0.1Eu 3+ .

[0035] Example 4 A preparation method of europium and terbium doped fluorapatite phosphor is the same as the preparation method of Example 1, except that Tb 3+ With Eu 3+ The molar ratio is replaced by 0.08:0.1 to 0.02:0.1, comprising the following steps: S1. Dissolve 4.55 mmol of SrCl2, 0.1 mmol of Tb(NO3)3, 0.5 mmol of Eu(NO3)3 and 3 mmol of NH4H2PO4 in 25 mL of water, add 3 mL of N2H4•H2O, and stir magnetically at room temperature for 10 min to obtain a mixed solution.

[0036] S2. Add 1 mmol of [Omim]PF6 to the mixed solution and stir the mixture at room temperature for 20 minutes to generate a precipitate. The precipitate is then washed with deionized water and ethanol in sequence. After washing, the precipitate is placed in an oven and dried at 60°C for 12 hours to obtain europium and terbium doped fluoroapatite phosphor, which is recorded as Sr5(PO4)3F:Tb 3+ ,Eu 3+ Phosphor, abbreviated as 0.02Tb 3+ ,0.1Eu 3+ .

[0037] Example 5 A preparation method of europium and terbium doped fluorapatite phosphor is the same as the preparation method of Example 1, except that Tb 3+ With Eu 3+The molar ratio is replaced by 0.08:0.1:0.1, comprising the following steps: S1. Dissolve 4.55 mmol of SrCl2, 0.5 mmol of Tb(NO3)3, 0.5 mmol of Eu(NO3)3 and 3 mmol of NH4H2PO4 in 25 mL of water, add 3 mL of N2H4•H2O, and stir magnetically at room temperature for 10 min to obtain a mixed solution.

[0038] S2. Add 1 mmol of [Omim]PF6 to the mixed solution and stir the mixture at room temperature for 20 minutes to generate a precipitate. The precipitate is then washed with deionized water and ethanol in sequence. After washing, the precipitate is placed in an oven and dried at 60°C for 12 hours to obtain europium and terbium doped fluoroapatite phosphor, which is recorded as Sr5(PO4)3F:Tb 3+ ,Eu 3+ Phosphor, abbreviated as 0.1Tb 3+ ,0.1Eu 3+ .

[0039] Example 6 A preparation method of europium and terbium doped fluorapatite phosphor is the same as the preparation method of Example 1, except that Tb 3+ With Eu 3+ The molar ratio is replaced by 0.08:0.1 to 0.01:0.1, comprising the following steps: S1. Dissolve 4.55 mmol of SrCl2, 0.05 mmol of Tb(NO3)3, 0.5 mmol of Eu(NO3)3 and 3 mmol of NH4H2PO4 in 25 mL of water, add 3 mL of N2H4•H2O, and stir magnetically at room temperature for 10 min to obtain a mixed solution.

[0040] S2. Add 1 mmol of [Omim]PF6 to the mixed solution and stir the mixture at room temperature for 20 minutes to generate a precipitate. The precipitate is then washed with deionized water and ethanol in sequence. After washing, the precipitate is placed in an oven and dried at 60°C for 12 hours to obtain europium and terbium doped fluoroapatite phosphor, which is recorded as Sr5(PO4)3F:Tb 3+ ,Eu 3+ Phosphor, abbreviated as 0.01Tb 3+ ,0.1Eu 3+ .

[0041] Example 7 A preparation method of europium and terbium doped fluorapatite phosphor is the same as the preparation method of Example 1, except that Tb 3+ With Eu3+ The molar ratio is replaced by 0.08:0.1 to 0.08:0.02, comprising the following steps: S1. Dissolve 4.55 mmol of SrCl2, 0.4 mmol of Tb(NO3)3, 0.1 mmol of Eu(NO3)3 and 3 mmol of NH4H2PO4 in 25 mL of water, add 3 mL of N2H4•H2O, and stir magnetically at room temperature for 10 min to obtain a mixed solution.

[0042] S2. Add 1 mmol of [Omim]PF6 to the mixed solution and stir the mixture at room temperature for 20 minutes to generate a precipitate. The precipitate is then washed with deionized water and ethanol in sequence. After washing, the precipitate is placed in an oven and dried at 60°C for 12 hours to obtain europium and terbium doped fluoroapatite phosphor, which is recorded as Sr5(PO4)3F:Tb 3+ ,Eu 3+ Phosphor, abbreviated as 0.08Tb 3+ ,0.02Eu 3+ .

[0043] Example 8 A preparation method of europium and terbium doped fluorapatite phosphor is the same as the preparation method of Example 1, except that Tb 3+ With Eu 3+ The molar ratio is replaced by 0.08:0.1 to 0.08:0.04, comprising the following steps: S1. Dissolve 4.55 mmol of SrCl2, 0.4 mmol of Tb(NO3)3, 0.2 mmol of Eu(NO3)3 and 3 mmol of NH4H2PO4 in 25 mL of water, add 3 mL of N2H4•H2O, and stir magnetically at room temperature for 10 min to obtain a mixed solution.

[0044] S2. Add 1 mmol of [Omim]PF6 to the mixed solution and stir the mixture at room temperature for 20 minutes to generate a precipitate. The precipitate is then washed with deionized water and ethanol in sequence. After washing, the precipitate is placed in an oven and dried at 60°C for 12 hours to obtain europium and terbium doped fluoroapatite phosphor, which is recorded as Sr5(PO4)3F:Tb 3+ ,Eu 3+ Phosphor, denoted as Sr5(PO4)3F:0.08Tb 3+ ,0.04Eu 3+ , abbreviated as 0.08Tb 3+ ,0.04Eu 3+ .

[0045] Example 9 A preparation method of europium and terbium doped fluorapatite phosphor is the same as the preparation method of Example 1, except that Tb 3+ With Eu 3+ The molar ratio is replaced by 0.08:0.1 to 0.08:0.06, comprising the following steps: S1. Dissolve 4.55 mmol of SrCl2, 0.4 mmol of Tb(NO3)3, 0.3 mmol of Eu(NO3)3 and 3 mmol of NH4H2PO4 in 25 mL of water, add 3 mL of N2H4•H2O, and stir magnetically at room temperature for 10 min to obtain a mixed solution.

[0046] S2. Add 1 mmol of [Omim]PF6 to the mixed solution and stir the mixture at room temperature for 20 minutes to generate a precipitate. The precipitate is then washed with deionized water and ethanol in sequence. After washing, the precipitate is placed in an oven and dried at 60°C for 12 hours to obtain europium and terbium doped fluoroapatite phosphor, which is recorded as Sr5(PO4)3F:Tb 3+ ,Eu 3+ Phosphor, abbreviated as 0.08Tb 3+ ,0.06Eu 3+ .

[0047] Example 10 A preparation method of europium and terbium doped fluorapatite phosphor is the same as the preparation method of Example 1, except that Tb 3+ With Eu 3+ The molar ratio is replaced by 0.08:0.1 to 0.08:0.08, comprising the following steps: S1. Dissolve 4.55 mmol of SrCl2, 0.4 mmol of Tb(NO3)3, 0.4 mmol of Eu(NO3)3 and 3 mmol of NH4H2PO4 in 25 mL of water, add 3 mL of N2H4•H2O, and stir magnetically at room temperature for 10 min to obtain a mixed solution.

[0048] S2. Add 1 mmol of [Omim]PF6 to the mixed solution and stir the mixture at room temperature for 20 minutes to generate a precipitate. The precipitate is then washed with deionized water and ethanol in sequence. After washing, the precipitate is placed in an oven and dried at 60°C for 12 hours to obtain europium and terbium doped fluoroapatite phosphor, which is recorded as Sr5(PO4)3F:Tb 3+ ,Eu 3+ Phosphor, abbreviated as 0.08Tb 3+ ,0.08Eu 3+ .

[0049] Comparative Example 1 A method for preparing terbium-doped fluorapatite phosphor is the same as the method in Example 1, except that Eu(NO3)3 is not added, and comprises the following steps: S1. Dissolve 4.55 mmol of SrCl2, 0.4 mmol of Tb(NO3)3 and 3 mmol of NH4H2PO4 in 25 mL of water, add 3 mL of N2H4•H2O, and stir magnetically at room temperature for 10 min to obtain a mixed solution.

[0050] S2. Add 1 mmol of [Omim]PF6 to the mixed solution, stir and react at room temperature for 20 minutes to generate a precipitate; then wash the precipitate with deionized water and ethanol in sequence. After washing, place it in an oven and dry it at 60°C for 12 hours to obtain terbium-doped fluoroapatite phosphor, which is recorded as Sr5(PO4)3F:0.08Tb 3+ , abbreviated as 0.08Tb 3+ .

[0051] Comparative Example 2 A method for preparing europium-doped fluorapatite phosphor is the same as the method in Example 1, except that Tb(NO3)3 is not added, and comprises the following steps: S1. Dissolve 4.55 mmol of SrCl2, 0.5 mmol of Eu(NO3)3 and 3 mmol of NH4H2PO4 in 25 mL of water, add 3 mL of N2H4•H2O, and stir magnetically at room temperature for 10 min to obtain a mixed solution.

[0052] S2. Add 1 mmol of [Omim]PF6 to the mixed solution, stir and react at room temperature for 20 minutes to generate a precipitate; then wash the precipitate with deionized water and ethanol in sequence. After washing, place it in an oven and dry it at 60°C for 12 hours to obtain europium and terbium doped fluoroapatite phosphor, recorded as Sr5(PO4)3F:0.1Eu 3+ , abbreviated as 0.1Eu 3+ .

[0053] Examples 1 to 4 of the present invention all produced europium and terbium co-doped fluorapatite phosphors with equivalent performance. Therefore, the europium and terbium co-doped fluorapatite phosphor of Example 1 was used as an example to study its performance.

[0054] Depend on Figure 1 It is concluded that there are two different Sr 2+The two sites are Sr1 and Sr2, respectively. Sr1 is located at the Wyckoff 4f position and is coordinated by nine oxygen (O) atoms, while Sr2 is located at the 6h position and is coordinated by six oxygen (O) atoms and one fluorine (F) atom.

[0055] Depend on Figure 2 The results show that the diffraction peaks of the europium and terbium doped fluorapatite phosphor of Example 1 are consistent with those of the standard card, and no additional diffraction peaks are found, which indicates that Tb 3+ and Eu 3+ The doping of Tb does not significantly change the crystal structure of SPF. 3+ With the increase of ion concentration, the characteristic diffraction peak gradually moves toward the high angle direction. The reason is that Tb 3+ ions replace the larger radius Sr 2+ sites, causing lattice contraction.

[0056] observe Figure 3 It is concluded that the europium and terbium dual-doped fluorapatite phosphor of the present invention has a nanorod structure, good crystallinity, and relatively uniform size distribution.

[0057] observe Figure 4 (a) shows that when monitored at 540 nm, the excitation spectrum shows a series of excitation peaks from 250 nm to 400 nm. The excitation spectrum shows an obvious broadening peak feature at 264 nm and a sharp peak signal with significantly increased intensity at 365 nm. The broadening peak at 264 nm is attributed to Tb 3+ Since there is obvious excitation at 365nm, strong green emission is observed at this excitation wavelength. 3+ , whose emission spectrum is at 540nm. Spectral analysis shows that the characteristic excitation peaks at 314nm, 349nm and 365nm are attributed to Tb 3+ of 7 F6 → 5 H7, 7 F6 → 5 D2 and 7 F6 → 5 G6 transition, this phenomenon is closely related to the ff forbidden transition characteristics of rare earth ions. Figure 4 (b) shows that for 0.1Eu 3+ When monitoring at 611nm, a series of excitation peaks from 200nm to 480nm were observed, and the band showed multi-peak excitation characteristics. 3+ The ions exhibit multiple characteristic absorption peaks, including: 313nm (corresponding to 7 F0→5 H5), 358nm (corresponding 7 F0→ 5 D4), 376nm (corresponding 7 F0→ 5 L7), 390nm (corresponding 7 F0→ 5 L6) and 461nm (corresponding to 7 F0→ 5 D2) has a narrow band absorption. Under 390nm excitation conditions, 0.1Eu 3+ The emission peak is located at 589nm (corresponding to 7 D0→ 7 F1), 611nm (corresponding 7 D0→ 7 F2), 645nm (corresponding 7 D0→ 7 F3) and 695nm (corresponding to 5 D0→ 7 F4).

[0058] Depend on Figure 4 (c) in the figure shows that, when monitored at 365nm, as the Tb 3+ The concentration of Tb ions and the excitation intensity also show an increasing trend, and the peak position and spectral morphology remain relatively consistent. 3+ When the doping concentration of Tb is less than 0.08, the luminescence intensity is relatively weak and the performance is poor due to the limited number of luminescence centers. However, when the doping concentration is higher than 0.08, concentration quenching effect occurs between adjacent luminescence centers, causing the emission intensity to gradually decrease. Therefore, Tb 3+ The excitation intensity is most significant when the concentration of ions reaches 0.08, which is the highest in Tb-doped europium and terbium-doped fluoroapatite phosphors. 3+ The ideal doping concentration of ions.

[0059] Depend on Figure 5 (a) shows that by monitoring at 610nm, 0.10Tb 3+ The emission spectrum and 0.1Eu 3+ The excitation spectra of Figure 5 (b) in the figure shows that by monitoring the Eu at 610 nm 3+ emission, and the excitation spectrum shapes at 350nm and 375nm were found to be similar to those of Tb 3+ When ions are doped alone, the excitation spectra at 350nm and 375nm have the same shape. 3+ to 0.1Eu 3+ Therefore, by changing the concentration of these two, it is possible to control the energy transfer of Tb 3+ and Eu3+ relative strength.

[0060] observe Figure 6 (a) in the above equation shows that Eu 3+ The higher the ion concentration, the higher the Tb 3+ The emission peak luminescence intensity of Eu 3+ The emission peak luminescence intensity is enhanced. This shows that in the europium and terbium doped fluoroapatite phosphor, energy can be transferred from Tb 3+ Transfer to EU 3+ It follows that by adjusting Eu 3+ The emission color of europium and terbium doped fluoroapatite phosphors can be controlled and changed by adjusting the doping concentration of europium and terbium ions. Figure 6 (b) shows the CIE chromaticity of the europium and terbium doped fluoroapatite phosphors of Examples 1 to 6, and the hues thereof change from yellow-green to yellow and finally to orange-red.

[0061] Figure 7 Shown 5 L6 fluorescence is Eu 3+ The energy transfer channel of ion elimination, from Tb 3+ to Eu 3+ The energy transfer efficiency is very high because Eu 3+ and Tb 3+ The emission spectra of the two materials have a large overlap. In the europium and terbium doped fluoroapatite phosphors, Tb 3+ With Eu 3+ The energy transfer between Tb and 3+ When the ion is excited, its electrons move from 7 F6 ground state transition to 5 D3 high energy state, then relaxes non-radiatively to 5 D6 intermediate energy level. When Tb 3+ The intermediate energy level of ions and Eu 3+ Ionic 5 When the D0 excited state energy levels match, energy is transferred to Eu through the dipole-dipole interaction. 3+ ions. When Tb 3+ With Eu 3+ When the local distance is less than the critical transfer radius, Tb 3+ Transfer part of the excitation energy to Eu 3+ of 5 D0 energy level, leading to Eu 3+ Characteristic red emission of 5 D0→ 7 F2 transition, 611nm) is enhanced, while Tb 3+ Green emission ( 5 D6→ 7F5, 540nm) gradually weakens. The energy transfer efficiency is similar to that of Eu 3+ The doping concentration of Eu 3+ The optimal balance is achieved when the concentration is 0.08, which ensures effective energy transfer while avoiding concentration quenching effect.

[0062] Depend on Figure 8 The results show that as the temperature increases from 298K to 498K, the luminescence intensity gradually decreases, while the position of the emission peak remains almost unchanged. This phenomenon is attributed to the thermal quenching effect. When the temperature rises to 498K, the initial emission intensity at 298K is still maintained at 72.42%. This demonstrates that the europium and terbium co-doped fluorapatite phosphor of Example 1 has good thermal stability.

[0063] In order to further evaluate the Sr5(PO4)3F:Tb 3+ ,Eu 3+ The potential application value of phosphor in the field of LED lighting is studied by mixing the europium and terbium doped fluoroapatite phosphor prepared in Example 8 with the commercial phosphor BaMgAl 10 O 17 :Eu 2+ They are respectively applied to the packaging of LED devices and carry out performance testing. Figure 9 It was found that the intensity, shape and position of the electroluminescence peak did not fluctuate significantly due to changes in current, which indicates that the europium and terbium dual-doped fluoroapatite phosphor of the present invention has relatively stable luminescence performance in LED devices. Figure 9 The illustration in the figure shows a photograph of the fabricated white light LED device. The CIE coordinates of this white light LED were calculated to be (0.3182, 0.2956), which gives the white light it emits a specific color. Its color temperature (CCT) is 6442K, close to that of natural light, providing comfortable and bright lighting. Its color rendering index (Ra) is 89.2, indicating that this white light LED faithfully reproduces the color of objects when illuminating, providing a high-quality lighting experience for a variety of applications.

[0064] It should be noted that when the present invention involves a numerical range, it should be understood that the two endpoints of each numerical range and any numerical value between the two endpoints can be selected. Since the steps and methods used are the same as those in the embodiment, in order to avoid redundancy, the present invention describes a preferred embodiment.

[0065] Although the preferred embodiments of the present invention have been described, those skilled in the art will be able to make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

Claims

1. A method for preparing europium and terbium doped fluorapatite phosphor, characterized in that: The steps include: Soluble strontium salt, soluble terbium salt, soluble europium salt, NH4H2PO4 and N2H4•H2O are dissolved in water to obtain a mixed solution; soluble hexafluorophosphate is added to the mixed solution to carry out a coprecipitation reaction. During the coprecipitation reaction, PF6 − Hydrolyzes and generates PO4 3- and F - , while the Sr in the mixed solution 2+ With PO4 3- and F - Combined to form Sr5(PO4)3F fluoroapatite structure, while Tb 3+ and Eu 3+ By replacing part of Sr 2+ Entering the crystal lattice of Sr5(PO4)3F, europium and terbium double-doped fluoroapatite phosphor is obtained; The coprecipitation reaction conditions are: stirring the reaction at room temperature for 20 minutes to 30 minutes.

2. The method for preparing europium and terbium co-doped fluorapatite phosphor according to claim 1, characterized in that: In the mixed solution, Sr 2+ , Tb 3+ 、Eu 3+ 、H2PO4 - The molar ratio to N2H4•H2O is 5:0.01~0.10:0.02~0.1:3:

1.

3. The method for preparing europium and terbium dual-doped fluorapatite phosphor according to claim 2, characterized in that: In the mixed solution, Sr 2+ , Tb 3+ 、Eu 3+ 、H2PO4 - The molar ratio of N2H4•H2O is 5:0.08:0.1:3:

1.

4. The method for preparing europium and terbium dual-doped fluorapatite phosphor according to claim 1, characterized in that: PF6 in soluble hexafluorophosphate − With Sr 2+ The molar ratio is 2:4.9~5.

3.

5. The method for preparing europium and terbium dual-doped fluorapatite phosphor according to claim 1, characterized in that: The soluble hexafluorophosphate is selected from 1-octyl-3-methylimidazolium hexafluorophosphate, 1-butyl-3-methylimidazolium hexafluorophosphate or 1-ethyl-3-methylimidazolium hexafluorophosphate.

6. A europium and terbium doped fluoroapatite phosphor, characterized in that: Prepared by the preparation method according to any one of claims 1 to 5.

7. The europium and terbium dual-doped fluorapatite phosphor according to claim 6, characterized in that: The crystal structure of the europium and terbium doped fluorapatite phosphor is a hexagonal fluorapatite structure.

8. The europium and terbium dual-doped fluorapatite phosphor according to claim 6, characterized in that: Europium and terbium doped fluoroapatite phosphor has a nanorod-like structure.

9. Use of the europium and terbium doped fluoroapatite phosphor according to claim 6 in the preparation of a fluorescence sensor or an optoelectronic device.

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