A rare earth doped two-color fluorescent material, a preparation method and application thereof

Abstract

The application discloses a rare earth doped double-color fluorescent material, a preparation method and application thereof, and has a chemical general formula of K3RESi6O 15 :xM, wherein 0.002<=x<=0.05; the RE is any one of praseodymium ions Pr 3+ , cerium ions Ce 3+ , terbium ions Tb 3+ ; the M is any one of samarium ions Sm 3+ , europium ions Eu 3+ , gadolinium ions Gd 3+ , terbium ions Tb 3+ , erbium ions Er 3+ , and the RE and the M are different rare earth ions. The rare earth element doped silicate inorganic fluorescent material has the ability of emitting light in multiple fluorescent light color domains (such as a red light region and a yellow-green light region) under different ultraviolet light excitation, and the fluorescent light emitting properties can be adjusted by changing the doped types and proportions of the rare earth elements to meet actual demands.

Description

Technical Field

[0001] This invention belongs to the field of luminescent materials technology, specifically relating to a rare earth-doped dual-color fluorescent material, its preparation method, and its application. Background Technology

[0002] Fluorescent materials are produced by calcining metal (zinc, chromium) sulfides or rare earth oxides with trace amounts of activators. They are colorless or pale white, but under ultraviolet light (200–400 nm), they exhibit various colors of visible light (400–800 nm) depending on the type and content of the metals and activators in the pigment. Fluorescent materials can be broadly classified into organic and inorganic categories. Rare earth fluorescent materials, due to their large Stokes shift, narrow emission peak, long fluorescence lifetime, and high emission intensity, have attracted considerable interest and have been successfully applied in many fields.

[0003] Rare earth metal-organic frameworks (MOFs) are novel inorganic-organic porous materials assembled from rare earth metal ions or clusters and organic bridging ligands through coordination interactions. MOFs offer new application opportunities for safer applications due to their multifunctional molecular design and independence from toxic metal ion activators. Traditional MOFs typically emit a specific color of light under excitation within a specific wavelength range, while dual-wavelength fluorescent materials emit two different colors of light under excitation at two different wavelengths, representing an upgrade from traditional fluorescent materials. Dual-wavelength fluorescent materials have better applications in display, anti-counterfeiting, information encryption, and biomarking. Therefore, developing such novel dual-wavelength fluorescent materials has become a research goal. Summary of the Invention

[0004] To address the aforementioned problems in the existing technology, the purpose of this invention is to provide a rare earth-doped dual-color fluorescent material, its preparation method, and its application.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A rare-earth-doped dual-color fluorescent material with the general chemical formula: K3RESi6O 15 :xM, where 0.002≤x≤0.05; the RE is rare earth praseodymium ion Pr 3+ cerium ions (Ce) 3+ terbium ions (Tb) 3+ Any one of them; M is samarium ion Sm 3+ Europium ions (Eu) 3+ Gadolinium ions (Gd) 3+ terbium ions (Tb) 3+ Erbium ion Er 3+ Any one of them, and the RE and the M are different rare earth ions.

[0007] Preferably, RE is terbium ion Tb 3+ M is europium ion Eu 3+ Its chemical formula is:

[0008] K3TbSi6O 15 0.01Eu 3+ .

[0009] This invention also discloses a method for preparing the above-mentioned rare-earth-doped dual-color fluorescent material, comprising the following steps:

[0010] (1) Synthetic matrix framework materials

[0011] Trivalent rare earth salts were mixed with a silicon source, a template agent, and a reaction solvent in a specific ratio and then placed in a sealed reaction vessel. The mixture was heated at 100–1000°C for 24–480 hours. The precipitate was filtered, washed with distilled water, and dried to obtain a crystalline product containing K3RESi6O. 15 The chemical formula of;

[0012] (2) Synthesis of rare earth-doped dual-color fluorescent materials

[0013] The crystal product obtained in step (1) is mixed with the doped rare earth salt aqueous solution in a certain proportion, stirred at a constant temperature of -10 to 150℃ for 0.5 to 72 hours, allowed to stand and settle, the solid product is washed with distilled water and dried to obtain rare earth doped dual-color fluorescent material.

[0014] Preferably, the trivalent rare earth salt in step (1) is selected from any one of the following: ground or unground chlorides, nitrates, sulfates, carbonates, phosphates of praseodymium ions, cerium ions, and terbium ions, as well as their hydrates.

[0015] The doped rare earth salts mentioned in step (2) are selected from any one of the chloride, nitrate, sulfate, carbonate, phosphate, and hydrates of samarium ions, europium ions, gadolinium ions, and erbium ions.

[0016] Preferably, the silicon source in step (1) is one or more of water glass, silica, silica sol, methyl orthosilicate, and ethyl orthosilicate.

[0017] Preferably, the template agent in step (1) is an aqueous solution of NaOH or KOH with a concentration of 0.1-10 mol / L.

[0018] Preferably, the molar ratio of rare earth salt, silicon source and template agent in step (1) is 1:10-300:10-200; the molar ratio of crystal product to doped rare earth salt in step (2) is 1:1-2.

[0019] Preferably, the reaction solvent in step (1) is selected from one or more of deionized water, ethanol, propanol, n-butanol, isobutanol, n-pentanol, polyethylene glycol, and imidazole ionic liquids.

[0020] Preferably, the concentration of the rare earth salt aqueous solution in step (2) is 0.001 to 20 mol / L.

[0021] This invention also discloses the application of the above-mentioned fluorescent materials in display, anti-counterfeiting, information encryption, and biomarker materials.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The rare earth element-doped silicate inorganic fluorescent material provided by this invention has the ability to emit light in multiple fluorescence emission color gamuts (such as the red light region and the yellow-green light region) under different ultraviolet light excitation, and the fluorescence emission properties can be adjusted by changing the doping type and ratio of rare earth elements to meet practical needs. Attached Figure Description

[0024] Figure 1 CJU-1-TbSiO:0.01Eu prepared in Example 4 3+ SEM image;

[0025] Figure 2 The structures of CJU-1-EuSiO, CJU-1-TbSiO, and CJU-1-TbSiO:0.01Eu were analyzed. 3+ Powder X-ray diffraction pattern of the experiment;

[0026] Figure 3 The excitation spectrum of CJU-1-TbSiO measured at a monitoring wavelength of 542 nm and the emission spectrum measured at an excitation wavelength of 376 nm are shown.

[0027] Figure 4 CJU-1-TbSiO:0.01Eu 3+ Excitation spectra measured at monitoring wavelengths of 542 nm and 612 nm and emission spectra measured at excitation wavelengths of 376 nm and 392 nm;

[0028] Figure 5 To investigate the effects of different wavelengths of ultraviolet light on CJU-1-TbSiO:0.01Eu 3+ Inspired photos;

[0029] Figure 6 The topological diagram of the CJU-1-EuSiO three-dimensional framework prepared in Comparative Example 4;

[0030] Figure 7Simulation of the CJU-1-EuSiO structure, CJU-1-EuSiO, CJU-1-EuSiO:Tb 3+ X-ray diffraction pattern of powder;

[0031] Figure 8 CJU-1-EuSiO:xTb 3+ (x = 0.01-0.05) CIE chromaticity coordinate diagram of phosphor;

[0032] Figure 9 The emission spectrum of CJU-1-CeSiO measured at an excitation wavelength of 313 nm;

[0033] Figure 10 The emission spectrum of CJU-1-PrSiO was measured at an excitation wavelength of 270 nm. Detailed Implementation

[0034] Embodiments of the present invention are described below, examples of which are shown in the accompanying drawings. The embodiments described with reference to the drawings are exemplary and intended to explain the present invention, but are not to be construed as limiting the present invention.

[0035] Example 1

[0036] 0.3 mL of 0.1 mol / L cerium phosphate solution was dissolved in a mixed solution of 10 mL of 0.1 mol / L KOH and 1 mL of water glass, and then dispersed in 5 mL of anhydrous ethanol. The mixture was then placed in a hydrothermal reactor and sealed. The reactor was heated at 180 °C for 200 hours. After the reaction was complete, the precipitate was filtered and washed with ethanol and distilled water, and dried at 60 °C to obtain the rare earth silicate matrix material K3CeSi6O. 15 The crystalline product is denoted as CJU-1-CeSiO.

[0037] Example 2

[0038] 0.6 mL of 0.1 mol / L TbCl3·6H2O solution was dissolved in a mixed solution of 7 mL of 0.1 mol / L KOH and 1.05 mL of silica sol, and then dispersed in 5 mL of aqueous solution. The mixture was then placed in a hydrothermal reactor and sealed. The reactor was heated at 240 °C for 160 hours. After the reaction was complete, the precipitate was filtered and washed with ethanol and distilled water, and dried at 60 °C to obtain the rare earth silicate matrix material K3TbSi6O. 15 The crystalline product is denoted as CJU-1-TbSiO.

[0039] Example 3

[0040] 0.6 mL of 0.1 mol / L PrCl3·6H2O solution was dissolved in a mixed solution of 7 mL of 0.1 mol / L KOH and 1.50 mL of silica sol, and then dispersed in 2 mL of aqueous solution. The mixture was then placed in a hydrothermal reactor and sealed. The reactor was heated at 240 °C for 100 hours. After the reaction was complete, the precipitate was filtered and washed with ethanol and distilled water, and dried at 60 °C to obtain the rare earth silicate matrix material K3PrSi6O. 15 The crystalline product is denoted as CJU-1-PrSiO.

[0041] Example 4

[0042] Add 1.0 mL of 0.1 mol / L EuCl3·6H2O aqueous solution to 0.10 g of K3TbSi6O prepared in Example 2. 15 A mixture of terbium and 15 mL of ultrapure water was stirred in an 80°C water bath for 24 hours. After settling, the mixture was filtered and washed. The product was then dried in a 230°C oven to obtain the terbium-doped fluorescent material: K3TbSi6O. 15 0.01Eu 3+ It is denoted as CJU-1-TbSiO:0.01Eu 3+ .

[0043] The phase structure and phase purity of the fluorescent material prepared in Example 4 were characterized by powder X-ray diffraction (PXRD). Figure 2 The results demonstrate CJU-1-EuSiO based on single-crystal structure data simulation, experimentally measured CJU-1-TbSiO prepared in Example 2, and CJU-1-TbSiO prepared in Example 4 with a concentration of 0.01 Eu. 3+ The X-ray diffraction patterns of the powders showed that the peak positions and intensity trends of all samples matched the matrix, with no redundant peaks. Experimental results indicate that the CJU-1-TbSiO and CJU-1-EuSiO matrices are isomorphic, and the Eu... 3+ Ion doping did not cause any change in the crystal structure of the CJU-1-TbSiO matrix, and the resulting product was a pure phase.

[0044] Figure 3 The excitation spectrum of CJU-1-TbSiO measured at a monitoring wavelength of 542 nm and the emission spectrum measured at an excitation wavelength of 376 nm are shown. The excitation spectrum of CJU-1-TbSiO in the ultraviolet region contains three distinct excitation bands from 300 nm to 400 nm, which are attributed to Tb. 3+ The characteristic 4f-4f transitions correspond to, respectively 7 F6- 5 L8 (340nm), 7 F6- 5 L9 (352nm) and7 F6- 5 G6 (376nm) transition. Under 376nm ultraviolet excitation, K3TbSi6O... 15 It mainly emits green light, primarily in a narrow band, and mainly in... 5 D4- 7 The F5 (542nm) transition luminescence and the other three weaker emission distributions are 5 D4- 7 F6 (488nm) 5 D4- 7 F4 (588nm) and 5 D4- 7 The transition to the F3 (621nm) orbital.

[0045] Figure 4 CJU-1-TbSiO:0.01Eu was demonstrated. 3+ Excitation spectra measured at monitoring wavelengths of 542 nm and 612 nm, and emission spectra measured at excitation wavelengths of 376 nm and 392 nm. At 542 nm / 612 nm monitoring, Tb... 3+ / Eu 3+ The characteristic 4f-4f transition signals are those of the terbium ion. 7 F6- 5 H7 (319nm), 7 F6- 5 L9 (349nm and 352nm), 7 F6- 5 G6 (376nm) transition and europium ion 7 F0- 5 D4 (362nm), 7 F0- 5 G4 (380nm), 7 F0- 5 L6 (392nm) and 7 F0- 5 The D3 (416 nm) transition occurs. Based on the sample's excitation spectrum, two optimal excitation wavelengths are identified: 376 nm and 392 nm. When the sample is excited at 376 nm, it exhibits typical Tb values. 3+ Emission peak, corresponding 5 D4- 7 F J The transitions (J = 6, 5, 4, 3) are observed. When excited at a wavelength of 392 nm, the sample exhibits typical Eu transitions. 3+ Emission peak, corresponding 5 D0→ 7 F J (J=1,2,3,4) transitions.

[0046] Figure 5 Different wavelengths of ultraviolet light were used to examine CJU-1-TbSiO:0.01Eu. 3+ The excitation photograph, (a) shows CJU-1-TbSiO:0.01Eu irradiated with a 375nm wavelength ultraviolet lamp. 3+ The photographs of the phosphor show that the sample emits a bright green light. (b) is a photograph of the sample irradiated with a 392 nm ultraviolet lamp, showing a red emission. This result indicates that CJU-1-TbSiO:0.01Eu 3+ It has two emission centers, and different excitation wavelengths can make the sample emit green and red light.

[0047] Comparative Example 1

[0048] 0.6 mL of 0.1 mol / L erbium chloride solution was dissolved in a mixed solution of 6 mL of 0.1 mol / L KOH and 0.5 mL of silica sol, and then dispersed in 1 mL of aqueous solution. The mixture was then placed in a reaction vessel and sealed. The vessel was heated at 230 °C for 90 hours. After the reaction was complete, the precipitate was filtered and washed with ethanol and distilled water, and dried at 60 °C to obtain the rare earth silicate matrix material K3ErSi6O. 15 The crystalline product is denoted as CJU-1-ErSiO. Fluorescence curve analysis of CJU-1-ErSiO revealed that it does not exhibit fluorescence properties.

[0049] Comparative Example 2

[0050] 0.4 mL of 0.1 mol / L gadolinium chloride solution was dissolved in a mixed solution of 6 mL of 0.1 mol / L KOH and 0.4 mL of silica sol, and then dispersed in 5 mL of aqueous solution. The mixture was then placed in a reaction vessel and sealed. The vessel was heated at 240 °C for 100 hours. After the reaction was complete, the precipitate was filtered and washed with ethanol and distilled water, and dried at 60 °C to obtain the rare earth silicate matrix material K3GdSi6O. 15 The crystalline product is denoted as CJU-1-GdSiO. Fluorescence analysis of CJU-1-GdSiO revealed that it does not exhibit fluorescence.

[0051] Comparative Example 3

[0052] 0.75 mL of 0.1 mol / L samarium nitrate solution was dissolved in a mixed solution of 9 mL of 0.1 mol / L KOH and 1.2 mL of silica sol, and then dispersed in 8 mL of aqueous solution. The mixture was then placed in a reaction vessel and sealed. The vessel was heated at 220 °C for 80 hours. After the reaction was complete, the precipitate was filtered and washed with ethanol and distilled water, and dried at 60 °C to obtain the rare earth silicate matrix material K3SmSi6O. 15The crystalline product is denoted as CJU-1-SmSiO. Fluorescence curve analysis of CJU-1-SmSiO revealed that it does not exhibit fluorescence properties.

[0053] Comparative Example 4

[0054] 0.5 mL of 0.1 mol / L europium nitrate solution was dissolved in a mixed solution of 5 mL of 0.1 mol / L KOH and 0.6 mL of silica sol, and then dispersed in 1 mL of aqueous solution. The mixture was then placed in a hydrothermal reactor and sealed. The reactor was heated at 220 °C for 180 hours. After the reaction was complete, the precipitate was filtered and washed with ethanol and distilled water, and dried at 60 °C to obtain the rare earth silicate matrix material K3EuSi6O. 15 The crystalline product is denoted as CJU-1-EuSiO.

[0055] Comparative Example 5

[0056] Add 1.0 mL of 0.1 mol / L terbium chloride hexahydrate to 0.10 g of K3EuSi6O 15 The mixture was stirred in a terbium-doped silicate open framework material, K3EuSi6O, with 15 mL of ultrapure water for 24 hours at a constant temperature of 60 °C. After settling, the mixture was filtered, washed, and dried to obtain the terbium-doped silicate open framework material. 15 0.01Tb 3+ It is denoted as CJU-1-EuSiO:0.01Tb 3+ .

[0057] Select size as The rectangular crystal prepared in Comparative Example 5 was used for single-crystal structure analysis. X-ray single-crystal diffraction data were obtained using a Bruker D8X diffractometer equipped with monochromatic Cu-Kα radiation. Structural analysis indicates that the crystal belongs to the Pbam space group, and its unit cell parameters are... α=β=γ=90°, belonging to the orthorhombic crystal system, confirming that the synthesized crystal is CJU-1-EuSiO, and its three-dimensional framework topology is as follows. Figure 6 As shown, this is a three-dimensional open framework formed by [EuO6] octahedra and [SiO4] tetrahedra interconnected by oxygen atoms sharing vertices, containing an 8-membered ring channel defined by two [EuO6] octahedra and six [SiO4] tetrahedra in the

[100] direction. Water molecules and a portion of K... + Ions are located in the 8-membered ring channels, while other water molecules and K + The ions are located in the 6-membered ring channels where the

[001] direction and

[010] intersect. These abundant multi-element channels are conducive to the incorporation of rare earth ions.

[0058] The phase structure and phase purity of the fluorescent material prepared in Comparative Example 5 were characterized by powder X-ray diffraction (PXRD). Figure 7 The simulation of CJU-1-EuSiO based on single-crystal structure data was demonstrated, and the experimental results for CJU-1-EuSiO were obtained. The synthesized CJU-1-EuSiO had a density of 0.01 Tb. 3+ The powder X-ray diffraction patterns of the compounds showed that the diffraction peak positions and intensity trends of all samples matched the matrix, with no redundant peaks. Experimental results indicate that Tb... 3+ Ion doping did not cause any change in the crystal structure of the CJU-1-EuSiO matrix material, and the resulting product was a pure phase.

[0059] CJU-1-EuSiO:xTb was prepared according to the method of Comparative Example 5. 3+ (x = 0.01-0.05) fluorescent powder, Figure 8 The image shows CJU-1-EuSiO:xTb prepared in Comparative Example 5. 3+ (x = 0.01-0.05) CIE chromaticity coordinates of phosphors. From Figure 8 It can be seen that different concentrations of Tb doping 3+ After ionization, the chromaticity coordinates of all samples are located in the white light region. CJU-1-EuSiO:xTb 3+ (x=0.01-0.05) does not have the function of emitting two-color fluorescence.

[0060] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A rare-earth-doped dual-color fluorescent material, characterized in that, Chemical formula: K3RESi6O 15 : xM, wherein 0.002≤x≤0.05; the RE is terbium ion Tb 3+ ; the M is europium ion Eu 3+ .

2. The dual-color fluorescent material according to claim 1, wherein the rare earth element is selected from the group consisting of Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and combinations thereof. The chemical formula is: K3TbSi6O 15 :0.01Eu 3+ .

3. The method for preparing a rare earth doped bicolor fluorescent material according to claim 1 or 2, characterized in that, The method comprises the following steps: (1) synthesizing a matrix skeleton material The trivalent rare earth salt is mixed with a silicon source, a template agent and a reaction solvent in a certain proportion, and then is loaded into a closed reaction kettle. The kettle is heated at 100-1000°C for 24-480 hours. The precipitated product is filtered and washed with distilled water, and is dried to obtain a crystal product. The product has a chemical formula of K3RESi6O 15 . (2) synthesizing a rare earth doped double-color fluorescent material The crystal product obtained in step (1) is mixed with a rare earth doped salt aqueous solution in a certain proportion, and stirred at a constant temperature of-10-150℃ for 0.5-72 hours, then settled, and the solid product is washed with distilled water, and the product is dried to obtain a rare earth doped double-color fluorescent material.

4. The method of claim 3, wherein the method further comprises the step of: The trivalent rare earth salt in step (1) is selected from any one of ground or unground praseodymium ion, cerium ion, terbium ion chloride, nitrate, sulfate, carbonate, phosphate, and hydrates thereof; ​ The doped rare earth salt in step (2) is selected from any one of samarium ion, europium ion, gadolinium ion, erbium ion chloride, nitrate, sulfate, carbonate, phosphate, and hydrates thereof.

5. The method for preparing a rare-earth-doped dual-color fluorescent material according to claim 3, characterized in that, The silicon source in step (1) is one or more of water glass, white carbon black, silica sol, methyl orthosilicate, and ethyl orthosilicate.

6. The method for preparing a rare-earth-doped dual-color fluorescent material according to claim 3, characterized in that, The template agent in step (1) is an aqueous solution of NaOH or KOH with a concentration of 0.1-10 mol / L.

7. The method for preparing a rare-earth-doped dual-color fluorescent material according to claim 3, characterized in that, The molar ratio of the rare earth salt, the silicon source, and the template agent in step (1) is 1:10-300:10-200; and the molar ratio of the crystal product to the doped rare earth salt in step (2) is 1:1-2.

8. The method for preparing a rare-earth-doped dual-color fluorescent material according to claim 3, characterized in that, The reaction solvent in step (1) is selected from one or more of deionized water, ethanol, propanol, n-butanol, isobutanol, n-pentanol, polyethylene glycol, and imidazole ionic liquid.

9. The method for preparing a rare-earth-doped dual-color fluorescent material according to claim 3, characterized in that, The concentration of the rare earth salt aqueous solution in step (2) is 0.001-20 mol / L.

10. The fluorescent material according to claim 1 or 2, or the fluorescent material prepared by the preparation method of any one of claims 3-9, is applied in display, anti-counterfeiting, information encryption, and biomarker material.

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