Rare earth ion doped sodium yttrium fluoride nano material and preparation method and application thereof

Abstract

The invention relates to the technical field of nano luminescent materials, in particular to a rare earth ion doped sodium yttrium fluoride nano material as well as a preparation method and application thereof. The doping amount of ytterbium can influence the intensity of red light emitted by the nanometer material under the excitation of 1208 nm near-infrared light, the doping amount of thulium can influence the intensity of green light emitted by the nanometer material under the excitation of 1208 nm near-infrared light, the doping amount of holmium can influence the intensity of blue light emitted by the nanometer material under the excitation of 1208 nm near-infrared light, and by adjusting the doping amounts of ytterbium, thulium and holmium, the doping amount of the ytterbium, the doping amount of thulium and the doping amount of holmium can be adjusted. Further, the chromaticity diagram (CIE) coordinate position of the nano material is (0.3012, 0.3158), belongs to a white light range, and can be used for a white light LED device. In addition, the molar ratio of the yttrium source, the ytterbium source, the thulium source and the holmium source influences the light emitting color of the nanometer material under excitation of near-infrared light of 980 nm and 1208 nm, and therefore the nanometer material can be used for optical anti-counterfeiting.

Description

Technical Field

[0001] This invention relates to the field of nanoluminescent materials technology, specifically to a rare earth ion-doped sodium yttrium fluoride nanomaterial, its preparation method, and its application. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] White LEDs have attracted widespread attention due to their numerous advantages, including high efficiency, long lifespan, energy saving, and environmental friendliness. The most widely used and mature white LED technology on the market is phosphor conversion type. One type involves combining a blue LED with a yellow phosphor that can be effectively excited by blue light. Currently, commonly used white LEDs utilize Y3Al5O3. 12 :Ce 3+ Yellow phosphors are combined with Ga(In)N blue wafers to achieve white light emission. However, this type of white light-emitting diode has the problem of missing red light, which leads to its high color temperature, poor color rendering index, and low luminous efficiency.

[0004] Furthermore, in recent years, to prevent counterfeit and substandard products from disrupting the market and infringing on the rights and interests of consumers and merchants, various anti-counterfeiting methods have emerged. Existing anti-counterfeiting methods mainly include ink printing anti-counterfeiting technology, QR code anti-counterfeiting technology, and holographic anti-counterfeiting technology. These anti-counterfeiting technologies and methods each have their advantages and characteristics. QR code anti-counterfeiting is convenient for consumers to query and verify, but it is relatively easy to copy, and its anti-counterfeiting effect is limited. Holographic anti-counterfeiting is a physical anti-counterfeiting method that uses the refraction, reflection, and diffraction of light to present three-dimensional, dynamic, or color changes. While serving an aesthetic purpose, it also has the advantage of being difficult to copy. Its disadvantage is that it requires a high degree of material and flatness on the surface of the object to be covered. Anti-counterfeiting ink has higher anti-counterfeiting strength than QR codes, but its cost is also higher.

[0005] Rare earth luminescent nanomaterials possess characteristics such as narrow emission band, long fluorescence lifetime, low toxicity, large Stokes shift, tunable emission color, and no light bleaching or flickering. These excellent luminescent properties make them promising for applications in biomedicine, anti-counterfeiting, and lighting displays. Summary of the Invention

[0006] To overcome the above problems, this invention provides a rare earth ion-doped sodium yttrium fluoride nanomaterial, its preparation method, and its application.

[0007] To achieve the above technical objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a rare-earth ion-doped sodium yttrium fluoride nanomaterial with the chemical composition NaYF4:Yb 3+ / Tm 3+ / Ho 3+ , where Y 3+ With Yb 3+ Tm 3+ Ho 3+ The molar ratio is (12~88.9):(5~60):(1~10):(0.1~15).

[0008] In one or more implementation methods, Y 3+ With Yb 3+ Tm 3+ Ho 3+ The molar ratio is 38:50:7:5. Under near-infrared light excitation at 1208 nm, the chromaticity diagram (CIE) coordinates of the rare-earth ion-doped sodium yttrium fluoride nanomaterials with this molar ratio are (0.3012, 0.3158), which falls within the white light range.

[0009] In one or more implementation methods, Y 3+ With Yb 3+ Tm 3+ Ho 3+ The molar ratios are (12~88.9):(5~60):(1~10):(0.1~15); specifically: (86.7~86.9):10:3:(0.1~0.3), (84~86):10:3:(1~3), (80~82):10:3:(5~7), (72~78):10:3:(9~15), (86.3~86.7):10:3:(0.3~0.7); Specifically, Y 3+ With Yb 3+ Tm 3+ Ho 3+ When the molar ratio of rare earth ion-doped sodium yttrium fluoride nanomaterials is (86.7~86.9):10:3:(0.1~0.3), the nanomaterials emit violet light when excited by 980 nm near-infrared light. Y 3+ With Yb 3+ Tm 3+ Ho 3+ When the molar ratio of rare earth ions to sodium yttrium fluoride nanomaterials is (84~86):10:3:(1~3), the rare earth ion-doped sodium yttrium fluoride nanomaterials emit blue light when excited by 980 nm near-infrared light. Y 3+ With Yb 3+ Tm 3+ Ho 3+When the molar ratio of rare earth ions to sodium yttrium fluoride nanomaterials is (80~82):10:3:(5~7), the rare earth ion-doped sodium yttrium fluoride nanomaterials emit green light under 980 nm near-infrared light excitation. Y 3+ With Yb 3+ Tm 3+ Ho 3+ When the molar ratio of rare earth ion-doped sodium yttrium fluoride nanomaterials is (72~78):10:3:(9~15), the rare earth ion-doped sodium yttrium fluoride nanomaterials emit yellow-orange light under 980 nm near-infrared light excitation. Y 3+ With Yb 3+ Tm 3+ Ho 3+ When the molar ratio is 84:10:3:3, rare earth ion-doped sodium yttrium fluoride nanomaterials emit red light when excited by 1208 nm near-infrared light.

[0010] Y 3+ With Yb 3+ Tm 3+ Ho 3+ When the molar ratio of rare earth ion-doped sodium yttrium fluoride nanomaterials is (86.3~86.7):10:3:(0.3~0.7), the nanomaterials emit violet light when excited by 1208 nm near-infrared light. In addition to the aforementioned proportions, in Y 3+ With Yb 3+ Tm 3+ Ho 3+ The molar ratios of the materials are in the range of (12~88.9):(5~60):(1~10):(0.1~15). Materials with other molar ratios emit red light when excited by 1208 nm near-infrared light.

[0011] A second aspect of the present invention provides a method for preparing the rare-earth ion-doped sodium yttrium fluoride nanomaterials described in the first aspect, comprising the following steps: Sodium source was added to an aqueous solution of ethylenediaminetetraacetic acid (EDTA), followed by the addition of yttrium source, ytterbium source, thulium source, holmium source and fluorine source. Rare earth ion-doped sodium yttrium fluoride nanomaterials were obtained by heat treatment under acidic conditions.

[0012] In one or more embodiments, the sodium source is sodium hydroxide.

[0013] In one or more embodiments, the yttrium source is yttrium acetate.

[0014] In one or more embodiments, the ytterbium source is ytterbium acetate.

[0015] In one or more embodiments, the thulium source is thulium acetate.

[0016] In one or more embodiments, the holmium source is holmium acetate.

[0017] In one or more embodiments, the fluorine source is ammonium fluoride.

[0018] In one or more embodiments, the molar ratio of the sodium source to ethylenediaminetetraacetic acid is (1.9~2.3):(0.4~0.7).

[0019] In one or more embodiments, the concentration of the aqueous solution of ethylenediaminetetraacetic acid is 0.08~0.014 mol / L.

[0020] In one or more embodiments, the molar ratio of the sodium source to the fluorine source is (1.9~2.3):(6~7).

[0021] In one or more embodiments, the molar ratio of yttrium source, ytterbium source, thulium source and holmium source is (12~88.9):(5~60):(1~10):(0.1~15).

[0022] In one or more embodiments, the heat treatment temperature is 180~250 °C, preferably 200 °C; the heat treatment time is 19~23 h, preferably 20 h.

[0023] A third aspect of the present invention provides the application of rare earth ion-doped sodium yttrium fluoride nanomaterials as described in the first aspect or prepared by the preparation method described in the second aspect in optical anti-counterfeiting and white LED devices.

[0024] In one or more implementations, Y 3+ With Yb 3+ Tm 3+ Ho 3+ The molar ratios are (12~88.9):(5~60):(1~10):(0.1~15); specifically: (86.7~86.9):10:3:(0.1~0.3), (84~86):10:3:(1~3), (80~82):10:3:(5~7), (72~78):10:3:(9~15), (86.3~86.7):10:3:(0.3~0.7); Specifically, Y 3+ With Yb 3+ Tm 3+ Ho 3+ When the molar ratio of rare earth ion-doped sodium yttrium fluoride nanomaterials is (86.7~86.9):10:3:(0.1~0.3), the nanomaterials emit violet light when excited by 980 nm near-infrared light. Y 3+ With Yb3+ Tm 3+ Ho 3+ When the molar ratio of rare earth ions to sodium yttrium fluoride nanomaterials is (84~86):10:3:(1~3), the rare earth ion-doped sodium yttrium fluoride nanomaterials emit blue light when excited by 980 nm near-infrared light. Y 3+ With Yb 3+ Tm 3+ Ho 3+ When the molar ratio of rare earth ions to sodium yttrium fluoride nanomaterials is (80~82):10:3:(5~7), the rare earth ion-doped sodium yttrium fluoride nanomaterials emit green light under 980 nm near-infrared light excitation. Y 3+ With Yb 3+ Tm 3+ Ho 3+ When the molar ratio of rare earth ion-doped sodium yttrium fluoride nanomaterials is (72~78):10:3:(9~15), the rare earth ion-doped sodium yttrium fluoride nanomaterials emit yellow-orange light under 980 nm near-infrared light excitation. Y 3+ With Yb 3+ Tm 3+ Ho 3+ When the molar ratio is 84:10:3:3, rare earth ion-doped sodium yttrium fluoride nanomaterials emit red light when excited by 1208 nm near-infrared light.

[0025] Y 3+ With Yb 3+ Tm 3+ Ho 3+ When the molar ratio of rare earth ion-doped sodium yttrium fluoride nanomaterials is (86.3~86.7):10:3:(0.3~0.7), the nanomaterials emit violet light when excited by 1208 nm near-infrared light. In addition to the aforementioned proportions, in Y 3+ With Yb 3+ Tm 3+ Ho 3+ The molar ratios of the materials are in the range of (12~88.9):(5~60):(1~10):(0.1~15). Materials with other molar ratios emit red light when excited by 1208 nm near-infrared light.

[0026] In one or more implementation methods, Y 3+ With Yb 3+ Tm 3+ Ho 3+The molar ratio is 38:50:7:5. Under near-infrared light excitation at 1208 nm, the chromaticity diagram (CIE) coordinates of the rare-earth ion-doped sodium yttrium fluoride nanomaterials with this molar ratio are (0.3012, 0.3158), which falls within the white light range and can be used in white LED devices.

[0027] A fourth aspect of the present invention provides an anti-counterfeiting ink comprising the rare earth ion-doped sodium yttrium fluoride nanomaterials described in the first aspect or the rare earth ion-doped sodium yttrium fluoride nanomaterials prepared by the preparation method described in the second aspect.

[0028] In one or more implementation methods, Y 3+ With Yb 3+ Tm 3+ Ho 3+ The molar ratio is (12~88.9):(5~60):(1~10):(0.1~15).

[0029] A fifth aspect of the present invention provides a white LED device, wherein the white LED device is filled with the rare earth ion-doped sodium yttrium fluoride nanomaterial described in the first aspect or the rare earth ion-doped sodium yttrium fluoride nanomaterial prepared by the preparation method described in the second aspect.

[0030] In one or more implementation methods, Y 3+ With Yb 3+ Tm 3+ Ho 3+ The molar ratio is 38:50:7:5.

[0031] The beneficial effects of this invention are as follows: (1) The doping amount of ytterbium can affect the intensity of red light emitted by the nanomaterial under 1208 nm near-infrared light excitation, the doping amount of thulium can affect the intensity of green light emitted by the nanomaterial under 1208 nm near-infrared light excitation, and the doping amount of holmium can affect the intensity of blue light emitted by the nanomaterial under 1208 nm near-infrared light excitation. By adjusting the doping amounts of ytterbium, thulium, and holmium, the chromaticity diagram (CIE) coordinate position of the nanomaterial is (0.3012, 0.3158), which is within the white light range and can be used in white LED devices. The rare earth ion-doped sodium yttrium fluoride nanomaterial provided by this invention has a small effect on the luminous intensity due to temperature and good luminous stability, which is beneficial for long-term illumination.

[0032] (2) In addition, the molar ratio of yttrium source, ytterbium source, thulium source and holmium source affects the emission color of nanomaterials under near-infrared light excitation at 980 nm and 1208 nm, which can then be used for optical anti-counterfeiting.

[0033] (3) The rare earth ion-doped sodium yttrium fluoride nanomaterials provided by the present invention have a simple preparation process and low cost, which is conducive to realizing large-scale industrial production. Attached Figure Description

[0034] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0035] Figure 1 Rare earth ion-doped sodium yttrium fluoride nanomaterial NaYF4:7%Tm 3+ / 5%Ho 3+ / 10%Yb 3+ Scanning electron microscope image; Figure 2 Rare earth ion-doped sodium yttrium fluoride nanomaterial NaYF4:7%Tm 3+ / 5%Ho 3+ / 10%Yb 3+ X-ray diffraction pattern; Figure 3 Rare earth ion-doped sodium yttrium fluoride nanomaterial NaYF4:7%Tm 3+ / 5%Ho 3+ / x%Yb 3+ With Yb 3+ Emission spectra of concentration changes; Figure 4 Rare earth ion-doped sodium yttrium fluoride nanomaterial NaYF4:7%Tm 3+ / 5%Ho 3+ / x%Yb 3+ The luminescence intensity at 646 nm varies with Yb 3+ Concentration change graph; Figure 5 Rare earth ion-doped sodium yttrium fluoride nanomaterial NaYF4:x%Tm 3+ / 5%Ho 3+ / 10%Yb 3+ With Tm 3+ Emission spectra of concentration changes; Figure 6 Rare earth ion-doped sodium yttrium fluoride nanomaterial NaYF4:x%Tm 3+ / 5%Ho 3+ / 10%Yb 3+ The luminescence intensity at 540 nm varies with Tm 3+ Concentration change graph; Figure 7 Rare earth ion-doped sodium yttrium fluoride nanomaterial NaYF4:3%Tm 3+ / x%Ho 3+ / 10%Yb3+ Follow Ho 3+ Emission spectra of concentration changes; Figure 8 Rare earth ion-doped sodium yttrium fluoride nanomaterial NaYF4:3%Tm 3+ / x%Ho 3+ / 10%Yb 3+ The luminescence intensity at 476 nm varies with Ho. 3+ Concentration change graph; Figure 9 Rare earth ion-doped sodium yttrium fluoride nanomaterial NaYF4:7%Tm 3+ / 5%Ho 3+ / 0.5%Yb 3+ The chromaticity diagram (CIE); Figure 10 Rare earth ion-doped sodium yttrium fluoride nanomaterial NaYF4:7%Tm 3+ / 5%Ho 3+ / 0.5%Yb 3+ Spectrum under 1208 nm near-infrared light excitation; Figure 11 Ca5(PO4)3OH:Tb 3+ X-ray diffraction pattern of nanoparticles; Figure 12 To achieve Ca5(PO4)3OH:Tb under 371 nm light excitation 3+ The emission spectrum; Figure 13 The anti-counterfeiting spectra under different wavelengths (371nm, 980nm, 1208nm); Figure 14 NaYF4:Yb 3+ / Tm 3+ / Ho 3+ The upconversion energy transfer mechanism. Detailed Implementation

[0036] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0037] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0038] To enable those skilled in the art to better 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.

[0039] Example 1 NaYF4:7%Tm 3+ / 5%Ho 3+ / x%Yb 3+ Preparation of (x = 5, 10, 20, 40, 50, 60, and 70): Dissolve 0.16 g EDTA in 5 mL of deionized water, then add 0.42 mL of 5 mol / L NaOH aqueous solution and stir for 30 min until well mixed. Add 0.07 mmol thulium acetate, 0.05 mmol holmium acetate, a mmol ytterbium acetate, and (0.88-a) mmol yttrium acetate, where a is 0.05, 0.1, 0.2, 0.4, 0.5, 0.6, and 0.7. Subsequently, 3.2 mL of 2 mol / L ammonium fluoride aqueous solution and 4 mL of 1 mol / L hydrochloric acid solution were added and mixed thoroughly again. The mixture was then transferred to a high-pressure reactor lined with polytetrafluoroethylene and placed in an oven at 200 °C for 20 h. After cooling to room temperature, the solid was collected by centrifugation (6000 rpm, 10 min), washed several times with deionized water and ethanol, and then dried in a drying oven to obtain rare earth ion-doped sodium yttrium fluoride nanomaterials NaYF4:7%Tm. 3+ / 5%Ho 3+ / x%Yb 3+ .

[0040] Figure 1 Rare earth ion-doped sodium yttrium fluoride nanomaterial NaYF4:7%Tm 3+ / 5%Ho 3+ / 10%Yb 3+ Scanning electron microscope images, from Figure 1 As can be seen from the image, the material is a rod-shaped object with a regular hexagonal base.

[0041] Figure 2 Rare earth ion-doped sodium yttrium fluoride nanomaterial NaYF4:7%Tm 3+ / 5%Ho 3+ / 10%Yb 3+ The X-ray diffraction pattern, from Figure 2 As can be seen from the data, the rare earth ion-doped sodium yttrium fluoride nanomaterial NaYF4:7%Tm 3+ / 5%Ho 3+ / 10%Yb 3+The XRD pattern is completely consistent with the standard card (JCPDS#16-0334), indicating that the prepared rare earth ion-doped sodium yttrium fluoride nanomaterial NaYF4:7%Tm 3+ / 5%Ho 3+ / 10%Yb 3+ It is a pure phase and contains no impurities.

[0042] Figure 3 Rare earth ion-doped sodium yttrium fluoride nanomaterial NaYF4:7%Tm 3+ / 5%Ho 3+ / x%Yb 3+ With Yb 3+ Emission spectra of concentration changes, such as Figure 3 As shown, under 1208 nm near-infrared light excitation, rare earth ion-doped sodium yttrium fluoride nanomaterials NaYF4:7%Tm 3+ / 5%Ho 3+ / x%Yb 3+ Its emission peak is 646 nm (red light).

[0043] Figure 4 Rare earth ion-doped sodium yttrium fluoride nanomaterial NaYF4:7%Tm 3+ / 5%Ho 3+ / x%Yb 3+ The luminescence intensity at 646 nm varies with Yb 3+ Concentration change graph.

[0044] Example 2 NaYF4:x%Tm 3+ / 5%Ho 3+ / 10%Yb 3+ Preparation of (x = 1, 3, 5, 7, and 10): Dissolve 0.16 g EDTA in 5 mL of deionized water, then add 0.42 mL of 5 mol / L NaOH aqueous solution and stir for 30 min until well mixed. Add b mmol thulium acetate, 0.05 mmol holmium acetate, 0.1 mmol ytterbium acetate, and (0.85-b) mmol yttrium acetate, where b is 0.01, 0.03, 0.05, 0.076, and 0.1, respectively. Subsequently, 3.2 mL of 2 mol / L ammonium fluoride aqueous solution and 4 mL of 1 mol / L hydrochloric acid solution were added and mixed thoroughly again. The mixture was then transferred to a high-pressure reactor lined with polytetrafluoroethylene and placed in an oven at 200 °C for 20 h. After cooling to room temperature, the solid was collected by centrifugation (6000 rpm, 10 min), washed several times with deionized water and ethanol, and then dried in a drying oven to obtain rare earth ion-doped sodium yttrium fluoride nanomaterial NaYF4:x%Tm. 3+ / 5%Ho 3+ / 10%Yb 3+ .

[0045] Figure 5 Rare earth ion-doped sodium yttrium fluoride nanomaterial NaYF4:x%Tm 3+ / 5%Ho 3+ / 10%Yb 3+ With Tm 3+ Emission spectra of concentration changes, such as Figure 5 As shown, under 1208 nm near-infrared light excitation, rare earth ion-doped sodium yttrium fluoride nanomaterial NaYF4:x%Tm 3+ / 5%Ho 3+ / 10%Yb 3+ There is a green emission peak at 540 nm.

[0046] Figure 6 Rare earth ion-doped sodium yttrium fluoride nanomaterial NaYF4:x%Tm 3+ / 5%Ho 3+ / 10%Yb 3+ The luminescence intensity at 540 nm varies with Tm 3+ Concentration change graph.

[0047] Example 3 NaYF4:3%Tm 3+ / x%Ho 3+ / 10%Yb 3+ Preparation of (x = 0.1, 0.3, 0.5, 0.7, 1, 3, 5, 7, 10 and 15): Dissolve 0.16 g EDTA in 5 mL of deionized water, then add 0.42 mL of 5 mol / L NaOH aqueous solution and stir for 30 min to mix thoroughly. Add 0.03 mmol thulium acetate, c mmol holmium acetate, 0.1 mmol ytterbium acetate, and (0.87-c) mmol yttrium acetate, where c is 0.001, 0.003, 0.005, 0.007, 0.01, 0.03, 0.05, 0.07, 0.1, and 0.15. Subsequently, 3.2 mL of 2 mol / L ammonium fluoride aqueous solution and 4 mL of 1 mol / L hydrochloric acid solution were added and mixed thoroughly again. The mixture was then transferred to a high-pressure reactor lined with polytetrafluoroethylene and placed in an oven at 200 °C for 20 h. After cooling to room temperature, the solid was collected by centrifugation (6000 rpm, 10 min), washed several times with deionized water and ethanol, and then dried in a drying oven to obtain rare earth ion-doped sodium yttrium fluoride nanomaterials NaYF4:3%Tm. 3+ / x%Ho 3+ / 10%Yb3+ .

[0048] Figure 7 Rare earth ion-doped sodium yttrium fluoride nanomaterial NaYF4:3%Tm 3+ / x%Ho 3+ / 10%Yb 3+ Follow Ho 3+ Emission spectra of concentration changes, such as Figure 7 As shown, under 1208 nm near-infrared light excitation, rare earth ion-doped sodium yttrium fluoride nanomaterials NaYF4:3%Tm 3+ / x%Ho 3+ / 10%Yb 3+ Its emission peak is 476 nm (blue light).

[0049] Figure 8 Rare earth ion-doped sodium yttrium fluoride nanomaterial NaYF4:3%Tm 3+ / x%Ho 3+ / 10%Yb 3+ The luminescence intensity at 476 nm varies with Ho 3+ Concentration change graph.

[0050] Example 4 As can be seen from Examples 1 to 3, the doping amount of ytterbium can affect the intensity of red light emitted by the nanomaterial under 1208 nm near-infrared light excitation, the doping amount of thulium can affect the intensity of green light emitted by the nanomaterial under 1208 nm near-infrared light excitation, and the doping amount of holmium can affect the intensity of blue light emitted by the nanomaterial under 1208 nm near-infrared light excitation.

[0051] By adjusting the doping amounts of ytterbium, thulium, and holmium, rare-earth ion-doped sodium yttrium fluoride nanomaterials NaYF4:7%Tm were obtained. 3+ / 5%Ho 3+ / 0.5%Yb 3+ Y 3+ With Yb 3+ Tm 3+ Ho 3+ The molar ratio is 38:50:7:5. For example... Figure 9 As shown, rare earth ion-doped sodium yttrium fluoride nanomaterials NaYF4:7%Tm 3+ / 5%Ho 3+ / 0.5%Yb 3+ Its chromaticity diagram (CIE) coordinates are (0.3012, 0.3158), which falls within the white light range and can be used in white LED devices. Figure 10 Rare earth ion-doped sodium yttrium fluoride nanomaterial NaYF4:7%Tm 3+ / 5%Ho 3+ / 0.5%Yb 3+ Spectrum under 1208 nm near-infrared light excitation.

[0052] Example 5 Ca5(PO4)3OH:Tb 3+ preparation: 0.4757 g Tb(NO3)3·6H2O and 0.0662 g CaCl2 were dispersed in 40 mL of deionized water and stirred until the solution was clear to obtain solution A. 0.3223 g Na2HPO4 was dispersed in 20 mL of deionized water and stirred until the solution was clear to obtain solution B. While stirring, solution B was added dropwise to solution A. The pH of the mixed solution was adjusted to 9.3 using 1 mol / L NaOH solution. The mixture was then transferred to a hydrothermal reactor and reacted at 60 °C for 1 h. After the reaction was complete, the solid was collected by centrifugation (13000 r / min, 15 min), washed with water, dried, and ground to obtain Ca5(PO4)3OH:Tb. 3+ Nanoparticles.

[0053] Figure 11 Ca5(PO4)3OH:Tb 3+ The X-ray diffraction pattern of the nanoparticles is completely consistent with the standard card, proving that they are pure phase.

[0054] Under 371 nm light excitation, Ca5(PO4)3OH:Tb 3+ It emits green light, and its emission spectrum is as follows: Figure 12 As shown.

[0055] Ca5(PO4)3OH:Tb 3+ Nanoparticles and NaYF4:Yb 3+ / Tm 3+ / Ho 3+ The anti-counterfeiting ink was obtained by dispersing the ingredients separately in polyvinyl alcohol. A perforated "Christmas tree" pattern was then overlaid on cardstock, and Ca5(PO4)3OH:Tb was used. 3+ Nanoparticle anti-counterfeiting ink is applied to the main body of the Christmas tree, with NaYF4:Yb coated at points a to k. 3+ / Tm 3+ / Ho 3+ Anti-counterfeiting ink, where dots a, b, and k are Y. 3+ With Yb 3+ Tm 3+ Ho 3+ The molar ratio is (72~78):10:3:(9~15); c, i point Y 3+ With Yb 3+ Tm 3+ Ho 3+The molar ratio is 84:10:3:3; points d, h, and j are Y. 3+ With Yb 3+ Tm 3+ Ho 3+ The molar ratio is (84~86):10:3:(1~3); point Y 3+ With Yb 3+ Tm 3+ Ho 3+ The molar ratio is 86.9:10:3:0.1; points g and f, Y 3+ With Yb 3+ Tm 3+ Ho 3+ The molar ratio was (80~82):10:3:(5~7). Different wavelengths (371 nm, 980 nm, 1208 nm) were used for excitation, the distribution pattern was read and compared with a preset key, and the results were as follows: Figure 13 As shown, under 371 nm light excitation, Ca5(PO4)3OH:Tb 3+ It emits green light, making the green Christmas tree bright, while the colored lights on the tree do not emit light; subsequently, under excitation with 980 nm and 1208 nm light, points a~k display colors respectively. Specifically, Y 3+ With Yb 3+ Tm 3 + Ho 3+ The molar ratio of rare earth ion-doped sodium yttrium fluoride nanomaterials is 86.9:10:3:0.1. Under this ratio, the nanomaterials emit violet light when excited by 980nm near-infrared light. 3+ With Yb 3+ Tm 3+ Ho 3+ The molar ratio of Yttrium fluoride nanomaterials to rare earth ions is (84~86):10:3:(1~3). Under this ratio, the nanomaterials emit blue light when excited by 980 nm near-infrared light. 3+ With Yb 3 + Tm 3+ Ho 3+ The molar ratio of Yttrium fluoride nanomaterials is (80~82):10:3:(5~7). Under this ratio, the rare earth ion-doped sodium yttrium fluoride nanomaterials emit green light when excited by 980 nm near-infrared light. 3+ With Yb 3+ Tm 3+ Ho 3+ The molar ratio of Yttrium fluoride nanomaterials to rare earth ions is (72~78):10:3:(9~15). Under this ratio, the rare earth ion-doped sodium yttrium fluoride nanomaterials emit yellow-orange light when excited by 980 nm near-infrared light. 3+With Yb 3+ Tm 3+ Ho 3+ The molar ratio is 84:10:3:3. Under this ratio, rare earth ion-doped sodium yttrium fluoride nanomaterials emit red light when excited by 1208 nm near-infrared light.

[0056] NaYF4:Yb 3+ / Tm 3+ / Ho 3+ Upconversion energy transfer mechanism such as Figure 14 As shown, under 1208 nm near-infrared light excitation, the occupied Tm 3+ Ionic 3 The electrons in the F4 ground state are excited to 3 F3 excited state, occupying Tm 3+ Ionic 3 Electrons in the H4 ground state are excited to 1 The G4 excited state then undergoes energy transfer, transferring energy to Yb. 3+ Ionic 2 F 5 / 2 Yb 3+ Ions transfer energy to Ho 3+ The ions are introduced into an excited state population through energy level transitions NaYF4:Yb 3+ / Tm 3+ / Ho 3+ Four distinct upconversion emission peaks are generated in the visible to near-infrared region, located at 483 nm. 1 G4→ 3 H6), 648 nm 1 G4→ 3 F4), 792 nm 3 H4→ 3 The upconversion peak of H6 corresponds to Tm 3+ Electronic transitions of ions, 657 nm ( 5 F5 → 5 I8); 535 nm 5 F4→ 5 The upconversion peak of I8 corresponds to Ho 3+ Electron transitions of ions.

[0057] Simultaneously, under 1208 nm near-infrared light excitation, occupying Ho 3+ ion 5 The electrons in the F3 ground state are excited to 3 L9 excited state, and transfer energy to Tm 3+ Ions are introduced to excite and populate their populations. This is achieved through energy level transitions in NaYF4:Yb. 3+ / Tm 3+ / Ho3+ A distinct upconversion emission peak is generated in the visible light region, located at 450 nm. 1 D2→ 3 The upconversion peak of F4 corresponds to Tm 3+ Electron transitions of ions.

[0058] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A rare-earth ion-doped sodium yttrium fluoride nanomaterial, characterized in that, Its chemical composition is NaYF4:Yb 3+ / Tm 3+ / Ho 3+ , where Y 3+ With Yb 3+ Tm 3+ Ho 3+ The molar ratio is (12~88.9):(5~60):(1~10):(0.1~15).

2. The rare-earth ion-doped sodium yttrium fluoride nanomaterial as described in claim 1, characterized in that, Y 3+ With Yb 3+ Tm 3+ Ho 3+ The molar ratio is 38:50:7:5; Or, Y 3+ With Yb 3+ Tm 3+ Ho 3+ The molar ratios are (12~88.9):(5~60):(1~10):(0.1~15); specifically: (86.7~86.9):10:3:(0.1~0.3), (84~86):10:3:(1~3), (80~82):10:3:(5~7), (72~78):10:3:(9~15), (86.3~86.7):10:3:(0.3~0.7).

3. The method for preparing rare earth ion-doped sodium yttrium fluoride nanomaterials according to claim 1 or 2, characterized in that, Includes the following steps: Sodium source was added to an aqueous solution of ethylenediaminetetraacetic acid (EDTA), followed by the addition of yttrium source, ytterbium source, thulium source, holmium source and fluorine source. Rare earth ion-doped sodium yttrium fluoride nanomaterials were obtained by heat treatment under acidic conditions.

4. The preparation method according to claim 3, characterized in that, The sodium source is sodium hydroxide; Alternatively, the yttrium source may be yttrium acetate; Alternatively, the ytterbium source may be ytterbium acetate; Alternatively, the thulium source is thulium acetate; Alternatively, the holmium source may be holmium acetate; Alternatively, the fluorine source may be ammonium fluoride; Alternatively, the molar ratio of the sodium source to ethylenediaminetetraacetic acid is (1.9~2.3):(0.4~0.7). Alternatively, the concentration of the aqueous solution of ethylenediaminetetraacetic acid is 0.08~0.014 mol / L; Alternatively, the molar ratio of the sodium source to the fluorine source is (1.9~2.3):(6~7). Alternatively, the molar ratio of yttrium source, ytterbium source, thulium source and holmium source is (12~88.9):(5~60):(1~10):(0.1~15); Alternatively, the heat treatment temperature is 180~250 ℃, preferably 200 ℃; the heat treatment time is 19~23 h, preferably 20 h.

5. The application of the rare earth ion-doped sodium yttrium fluoride nanomaterials according to claim 1 or 2, or the rare earth ion-doped sodium yttrium fluoride nanomaterials prepared by the preparation method according to claim 3 or 4, in optical anti-counterfeiting and white LED devices.

6. In the application described in claim 5, when rare earth ion-doped sodium yttrium fluoride nanomaterials are used in optical anti-counterfeiting applications, the specific ratios are: (86.7~86.9):10:3:(0.1~0.3), (84~86):10:3:(1~3), (80~82):10:3:(5~7), (72~78):10:3:(9~15), (86.3~86.7):10:3:(0.3~0.7); Alternatively, when using rare-earth ion-doped sodium yttrium fluoride nanomaterials in white LED devices, Y 3+ With Yb 3+ Tm 3+ Ho 3+ The molar ratio is 38:50:7:

5.

7. An anti-counterfeiting ink, characterized in that, This includes rare earth ion-doped sodium yttrium fluoride nanomaterials as described in claim 1 or 2, or rare earth ion-doped sodium yttrium fluoride nanomaterials prepared by the preparation method described in claim 3 or 4.

8. The anti-counterfeiting ink as described in claim 7, characterized in that, Y 3+ With Yb 3+ Tm 3+ Ho 3+ The molar ratios are (12~88.9):(5~60):(1~10):(0.1~15); specifically: (86.7~86.9):10:3:(0.1~0.3), (84~86):10:3:(1~3), (80~82):10:3:(5~7), (72~78):10:3:(9~15), (86.3~86.7):10:3:(0.3~0.7).

9. A white LED device, characterized in that, This includes rare earth ion-doped sodium yttrium fluoride nanomaterials as described in claim 1 or 2, or rare earth ion-doped sodium yttrium fluoride nanomaterials prepared by the preparation method described in claim 3 or 4.

10. The white LED device as described in claim 9, characterized in that, Y 3+ With Yb 3+ Tm 3+ Ho 3+ The molar ratio is 38:50:7:5.

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