A high-performance X-ray excited rare earth afterglow material, preparation method thereof and application thereof in the imaging field

Abstract

The present invention relates to the technical field of rare earth afterglow materials, and discloses a high-performance X-ray excited rare earth afterglow material, a preparation method thereof, and an application thereof in the imaging field. The general chemical composition formula thereof is: NaLu<subgt;z< / subgt;Y<subgt;0.7< / subgt;F<subgt;4< / subgt>@NaLu<subgt;0.8< / subgt;Bi<subgt;x< / subgt>F<subgt;4< / subgt>: Ba<subgt;Y< / subgt> / Dy<subgt;m< / subgt>@NaLu<subgt;z< / subgt>Y<subgt>0.7< / subgt>F<subgt;4< / subgt>. The high-performance X-ray excited rare earth afterglow material includes a total of three-layer structures, namely a core, an intermediate layer, and a shell layer. The core, the shell layer, and the intermediate layer have different matrix components, resulting in lattice mismatch at the shell layer interface. The present invention can generate strong afterglow luminescence after X-ray irradiation, has strong afterglow performance and a long afterglow duration, and can be used in the field of X-ray imaging.

Description

Technical Field

[0001] The present invention relates to the technical field of rare earth afterglow materials, and particularly to a high-performance X-ray excited rare earth afterglow material, a preparation method thereof, and an application thereof in the imaging field. Background Art

[0002] For X-ray imaging technology based on traditional bulk scintillators, it is difficult to obtain the three-dimensional structure inside an object. Usually, high X-ray radiation doses or complex instrument equipment are required to obtain three-dimensional information through image reconstruction. Compared with traditional bulk scintillators, it is easier to achieve three-dimensional imaging by developing new flexible X-ray detectors, and X-ray excited afterglow materials are a good choice. Research shows that rare earth ion-doped fluorides have X-ray excited afterglow properties and can be used to make flexible films to achieve three-dimensional imaging. However, their afterglow properties need to be achieved with high radiation doses and cannot meet the requirements of practical applications. It is urgent to explore effective methods to significantly improve the afterglow properties, thereby effectively reducing the irradiation dose and ensuring safety during use.

[0003] There are also some existing studies and applications related to X-ray excited rare earth afterglow materials.

[0004] (1) For example, the invention patent application with the application number 202011538445.7 and the title of Near-infrared II Region Luminescent Long Afterglow Nanoprobe Based on X-ray Excitation, Preparation Method Thereof, and Application Therein in In-vivo Imaging Analysis combines rare earth fluoride nanocrystals with small phonon energy and high luminescence efficiency with X-rays, regulates rare earth ion doping to construct a near-infrared II region long afterglow luminescent nanoprobe, and is used for deep in-vivo tissue imaging. However, the afterglow nanoprobe of this application has a core-shell two-layer structure, and its preparation method is also for preparing this afterglow nanoprobe, and its afterglow duration also needs to be improved.

[0005] (2) Another example is the invention patent application with the application number 202311466202.0 and the title of An Ultraviolet Luminescent Long Afterglow Material Based on X-ray Excitation and Its Application in High-Confidentiality X-ray Imaging Encryption. Its rare earth long afterglow nanoparticles have pure ultraviolet luminescence that is imperceptible to the naked eye. The prepared flexible memory film can achieve three-dimensional ray encryption of curved objects, has high spatial resolution and good recyclability; the encrypted X-ray imaging can be safely stored in the film and optically decoded through a layer of perovskite nanocrystals. However, it has a single-layer structure, and its afterglow duration needs to be improved.

[0006] (3) For the authorized invention patent with the application number 202410362486.7 and the name of "A Rare Earth Element Doped Pyrophosphate Long Afterglow Material Only Excitable by X - rays, Its Preparation Method and Application", this material can only be excited by X - rays and produce bright green, purple, red - brown, and orange - red light visible to the naked eye. It cannot be excited by white light and ultraviolet light. Therefore, it will not be affected by natural light in daily life. And after being irradiated by X - rays for a period of time, it can still be re - excited by hot water to emit bright green light, and can be used for daily personal household X - ray dose detection.

[0007] (4) For the invention patent application with the application number 202410696431.X and the name of "An X - ray Excited Borate Long Afterglow Luminescent Material and Its Preparation Method", it can be effectively excited by X - rays to produce long afterglow luminescence. The afterglow intensity is high and the duration is long. The borate long afterglow luminescent material prepared in the present invention can produce an afterglow in the range of 300nm - 400nm after being excited. The prepared borate long afterglow luminescent material can be mixed with organic polymer materials such as epoxy resin and curing agent to form a thin film or resin body, serving as a luminescent thin film or a luminescent device with blue afterglow. However, it mainly uses borate and is mainly applied to luminescent devices, and the afterglow duration still needs to be enhanced. Summary of the Invention

[0008] In order to overcome the deficiencies of the prior art, the purpose of the present invention is to provide a high - performance X - ray excited rare earth afterglow material, its preparation method and its application in the imaging field, which can produce strong afterglow luminescence after X - ray irradiation, has strong afterglow performance and a long afterglow duration, and can be used in the field of X - ray imaging technology, providing a new structural design idea for the development of high - performance rare earth afterglow materials.

[0009] The present invention is realized by the following technical scheme: A high - performance X - ray excited rare earth afterglow material, the general chemical formula is: NaLu z Y 0.7 F4@NaLu 0.8 Bi x F4:Ba Y / Dy m @NaLu z Y 0.7 F4,

[0010] where x is the molar content of Bi, 0.18 ≤ x ≤ 0.25, Y is the molar content of Ba, 0.12 ≤ Y ≤ 0.25, z is the molar content of Lu, 0.25 ≤ z ≤ 0.4, and m is the molar content of D y , 0.035 ≤ m ≤ 0.05.

[0011] Preferably, x = 0.2, Y = 0.2, z = 0.3, m = 0.04.

[0012] Preferably, the above-mentioned high-performance X-ray excited rare-earth afterglow material comprises a three-layer structure of a core, an intermediate layer, and a shell layer. The core and the shell layer are both NaLu 0.3 Y 0.7 F4, and the intermediate layer is NaLu 0.8 Bi 0.2 F4:Ba 0.2 / Dy 0.04 . The luminescence center is located in the intermediate layer, and a large number of Dy 3+ ions are located at the interface. The core, the shell layer, and the intermediate layer have different matrix components, resulting in lattice mismatch at the shell layer interface, reducing the binding energy of F - ions at the interface and increasing the formation probability of Frenkel defects at the interface.

[0013] Preferably, Bi 3+ ions are doped in the intermediate layer of the high-performance X-ray excited rare-earth afterglow material, which increases the X-ray absorption coefficient without changing the crystal structure.

[0014] Preferably, Ba 2+ ions are doped in the intermediate layer of the high-performance X-ray excited rare-earth afterglow material, generating F - ion vacancies in the lattice, forming defect energy levels, and improving the capture efficiency of secondary electrons and the energy transfer efficiency from secondary electrons to rare-earth ions.

[0015] A preparation method of a high-performance X-ray excited rare-earth afterglow material is used to prepare the above-mentioned high-performance X-ray excited rare-earth afterglow material, and it includes the following steps:

[0016] Step 1: First, prepare NaLu 0.3 Y 0.7 F4 core nanocrystals;

[0017] Step 2: Then, use the core nanocrystals in Step 1 to prepare NaLu 0.3 Y 0.7 F4@NaLu 0.8 Bi 0.2 F4:Ba Y / Dy m core-shell nanocrystals;

[0018] Step 3: Next, use the core-shell nanocrystals in Step 2 to prepare NaLu 0.3 Y 0.7 F4@NaLu 0.8 Bi 0.2 F4:Ba Y / Dy m @NaLu 0.3 Y 0.7 afterglow material.

[0019] Furthermore, the preparation steps of the core nanocrystals in Step 1 specifically include:

[0020] Step 11: Add 2 mmol of sodium acetate, 0.3 mmol of lutetium acetate, and 0.7 mmol of yttrium acetate to a mixed solution containing 6 - 8 mL of oleic acid and 8 - 10 mL of octadecene. Under the protection of nitrogen, keep it at a temperature of 140 - 160 °C for 1 hour to obtain a colorless transparent solution without water;

[0021] Step 12: After the solution is naturally cooled to room temperature, add 4 - 6 mL of a methanol solution containing 4 mmol of ammonium fluoride, and then keep it at 60 - 90 °C for half an hour;

[0022] Step 13: After all the methanol solution has evaporated, quickly raise the temperature to 290 - 310 °C, and keep it at this temperature for 80 - 100 minutes, and then naturally cool it to room temperature;

[0023] Step 14: Wash the obtained nanocrystals with a mixed solution of ethanol and cyclohexane to obtain NaLu 0.3 Y 0.7 F4 core nanocrystals, and store them in 4 - 6 mL of cyclohexane.

[0024] Furthermore, the preparation steps of the core - shell nanocrystals in Step 2 specifically include:

[0025] Step 21: Add 2 mmol of sodium acetate, 0.55 - 0.69 mmol of lutetium acetate, 0.2 mmol of bismuth acetate, 0.1 - 0.2 mmol of barium acetate, and 0.01 - 0.05 mmol of dysprosium acetate to a mixed solution containing 6 - 8 mL of oleic acid and 8 - 12 mL of octadecene. Under the protection of nitrogen, keep it at a temperature of 140 - 160 °C for 1 hour to obtain a colorless transparent solution without water;

[0026] Step 22: After the solution is naturally cooled to 70 °C, add the core nanocrystal solution obtained in Step 14 to the reaction solution in Step 21, and then keep it at 80 - 100 °C for half an hour;

[0027] Step 23: After the solution is naturally cooled to room temperature, add 8 - 12 mL of a methanol solution containing 4 mmol of ammonium fluoride, and then keep it at 60 - 80 °C for half an hour;

[0028] Step 24: After all the methanol solution has evaporated, quickly raise the temperature to 290 - 310 °C, and keep it at this temperature for 90 - 130 minutes, and then naturally cool it to room temperature;

[0029] Step 25: Wash the obtained nanocrystals with a mixed solution of ethanol and cyclohexane to obtain NaLu 0.3 Y 0.7 F4@NaLu0.8 Bi 0.2 F4: Ba Y / Dy m Core-shell nanocrystals, stored in 4-6 mL of cyclohexane.

[0030] Furthermore, the preparation steps of the rare earth afterglow material in step three specifically include:

[0031] Step 31: Add 2 mmol of sodium acetate, 0.3 mmol of lutetium acetate, and 0.7 mmol of yttrium acetate in molar percentage to a mixed solution containing 6-8 mL of oleic acid and 8-10 mL of octadecene. Under the protection of nitrogen, keep it at a temperature of 140-160 °C for 1 hour to obtain a clear anhydrous solution;

[0032] Step 32: After the solution is naturally cooled to 70 °C, add the core-shell nanocrystal solution obtained in step 25 to the reaction solution of step 31, and then keep it at 80-100 °C for half an hour;

[0033] Step 33: After the solution is naturally cooled to room temperature, add 8-12 mL of methanol solution containing 4 mmol of ammonium fluoride, and then keep it at 60-80 °C for half an hour;

[0034] Step 34: After all the methanol solution has evaporated, quickly raise the temperature to 290-310 °C, and keep it at this temperature for 100-120 minutes, and then naturally cool it to room temperature;

[0035] Step 35: Wash the obtained nanocrystals with a mixed solution of ethanol and cyclohexane, and after drying, obtain NaLu 0.3 Y 0.7 F4@NaLu 0.8 Bi 0.2 F4: Ba Y / Dy m @NaLu 0.3 Y 0.7 F4 afterglow material.

[0036] A high-performance X-ray excited rare earth afterglow material, which can be applied in the imaging field.

[0037] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0038] 1. A high-performance X-ray excited rare earth afterglow material of the present invention includes a three-layer structure of an inner core, an intermediate layer, and an outer shell layer. The luminescence center is located in the intermediate layer, and Bi 3+ ions are doped in the intermediate layer. Without changing the crystal structure, it can increase the X-ray absorption coefficient; Ba 2+ ions are doped in the intermediate layer, and Ba 2+ ions replace Lu 3+Ions occupy lattice sites. To maintain the charge balance of the system, F - ion vacancies are generated in the lattice, forming defect energy levels, which improve the secondary electron capture efficiency and the energy transfer efficiency from secondary electrons to rare earth ions; the core and the outer shell are NaLu 0.3 Y 0.7 F4, causing lattice mismatch at the shell interface and reducing the binding energy of F - ions at the interface, thus increasing the formation probability of Frenkel defects under X-ray excitation at the interface.

[0039] 2. A high-performance X-ray excited rare earth afterglow material of the present invention. When the product is irradiated by X-rays, a large number of defect states are formed at the interface, which can store a large number of secondary electrons. After the irradiation stops, these electrons are released and fill the excited state energy levels of rare earth ions, thereby generating strong afterglow luminescence with strong afterglow performance and long afterglow duration.

[0040] 3. A high-performance X-ray excited rare earth afterglow material of the present invention can be applied to the field of high-resolution and low-dose X-ray imaging technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 : X-ray diffraction pattern of NaLu 0.3 Y 0.7 F4@NaLu 0.8 Bi 0.2 F4: Ba Y / Dy m @NaLu 0.3 Y 0.7 F4;

[0042] Figure 2 : Transmission electron microscope image of NaLu 0.3 Y 0.7 F4@NaLu 0.8 Bi 0.2 F4: Ba Y / Dy m @NaLu 0.3 Y 0.7 F4;

[0043] Figure 3 : Afterglow spectrum of NaLu 0.3 Y 0.7 F4@NaLu 0.8 Bi 0.2 F4: Ba Y / Dy m @NaLu 0.3 Y 0.7 F4 after the X-ray excitation stops;

[0044] Figure 4 : NaLu in Example 2 0.3 Y 0.7 F4@NaLu 0.8 Bi 0.2 F4: Ba Y / Dy m @NaLu 0.3 Y 0.7 Afterglow spectrum of F4 after 5 days;

[0045] Figure 5 : NaLu in Example 2 0.3 Y 0.7 F4@NaLu 0.8 Bi 0.2 F4: Ba Y / Dy m @NaLu 0.3 Y 0.7 Relationship curve between afterglow intensity of F4 and Bi 3+ ion concentration;

[0046] Figure 6 : NaLu in Example 2 0.3 Y 0.7 F4@NaLu 0.8 Bi 0.2 F4: Ba Y / Dy m @NaLu 0.3 Y 0.7 Relationship curve between afterglow intensity of F4 and Ba 2+ ion concentration;

[0047] Figure 7 : NaLu in Example 2 0.3 Y 0.7 F4@NaLu 0.8 Bi 0.2 F4: Ba Y / Dy m @NaLu 0.3 Y 0.7 Relationship curve between afterglow intensity of F4 and Dy 3+ ion concentration;

[0048] Figure 8 : NaLu in Example 2 0.3 Y 0.7 F4@NaLu 0.8 Bi 0.2 F4: Ba Y / Dy m @NaLu 0.3 Y 0.7 Relationship curve between afterglow intensity of F4 and Lu in the outer shell layer3+ Relationship curve of ion concentration;

[0049] Figure 9 : Under X-ray excitation, NaLu 0.3 Y 0.7 F4@NaLu 0.8 Bi 0.2 F4: Ba Y / Dy m @NaLu 0.3 Y 0.7 Comparison of afterglow intensities between F4 and NaLuF4: Dy;

[0050] Figure 10 : NaLu in Example 4 0.3 Y 0.7 F4@NaLu 0.8 Bi 0.2 F4: Ba Y / Dy m @NaLu 0.3 Y 0.7 Imaging effect diagram of F4 afterglow luminescence. Specific implementation manners

[0051] The following specific examples illustrate the implementation manners of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation manners, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, without conflict, the following examples and the features in the examples can be combined with each other.

[0052] Example 1

[0053] A high-performance X-ray-excited rare-earth afterglow material, the general chemical formula is:

[0054] NaLu 0.3 Y 0.7 F4@NaLu 0.8 Bi 0.2 F4: Ba Y / Dy m @NaLu 0.3 Y 0.7 F4,[[ID=7K]]

[0055] Its preparation method successively includes the following steps:

[0056] Step 1: Prepare NaLu 0.3 Y 0.7 F4 core nanocrystals; specifically, it includes the following steps:

[0057] Step 11: Add 2 mmol of sodium acetate, 0.3 mmol of lutetium acetate, and 0.7 mmol of yttrium acetate into a mixed solution containing 6 - 8 mL of oleic acid and 8 - 10 mL of octadecene. Under the protection of nitrogen, keep it at a temperature of 140 - 160 °C for 1 hour to obtain a colorless transparent solution without water.

[0058] Step 12: After the solution naturally cools to room temperature, add 4 - 6 mL of a methanol solution containing 4 mmol of ammonium fluoride, and then keep it at 60 - 90 °C for half an hour.

[0059] Step 13: After all the methanol solution has evaporated, quickly raise the temperature to 290 - 310 °C, and keep it at this temperature for 80 - 100 minutes, and then naturally cool to room temperature.

[0060] Step 14: Wash the obtained nanocrystals with a mixed solution of ethanol and cyclohexane to obtain NaLu 0.3 Y 0.7 F4 core nanocrystals, and store them in 4 - 6 mL of cyclohexane.

[0061] Step Two: Use the core nanocrystals in Step One to prepare NaLu 0.3 Y 0.7 F4@NaLu 0.8 Bi 0.2 F4:Ba Y / Dy m core - shell nanocrystals; the specific steps are as follows:

[0062] Step 21: Add 2 mmol of sodium acetate, 0.55 - 0.69 mmol of lutetium acetate, 0.2 mmol of bismuth acetate, 0.1 - 0.2 mmol of barium acetate, and 0.01 - 0.05 mmol of dysprosium acetate into a mixed solution containing 6 - 8 mL of oleic acid and 8 - 12 mL of octadecene. Under the protection of nitrogen, keep it at a temperature of 140 - 160 °C for 1 hour to obtain a colorless transparent solution without water.

[0063] Step 22: After the solution naturally cools to 70 °C, add the core nanocrystal solution obtained in Step 14 into the reaction solution of Step 21, and then keep it at 80 - 100 °C for half an hour.

[0064] Step 23: After the solution naturally cools to room temperature, add 8 - 12 mL of a methanol solution containing 4 mmol of ammonium fluoride, and then keep it at 60 - 80 °C for half an hour.

[0065] Step 24: After all the methanol solution has evaporated, quickly raise the temperature to 290 - 310 °C, and keep it at this temperature for 90 - 130 minutes, and then naturally cool to room temperature.

[0066] Step 25: Wash the obtained nanocrystals with a mixed solution of ethanol and cyclohexane to obtain NaLu 0.3 Y 0.7 F4@NaLu 0.8 Bi 0.2 F4:Ba Y / Dy m core-shell nanocrystals, and store them in 4 - 6 mL of cyclohexane.

[0067] Step 3: Prepare NaLu using the core-shell nanocrystals in Step 2 0.3 Y 0.7 F4@NaLu 0.8 Bi 0.2 F4:Ba Y / Dy m @NaLu 0.3 Y 0.7 F4 afterglow material, which specifically includes the following steps:

[0068] Step 31: Add 2 mmol of sodium acetate, 0.3 mmol of lutetium acetate, and 0.7 mmol of yttrium acetate to a mixed solution containing 6 - 8 mL of oleic acid and 8 - 10 mL of octadecene, and keep it at a temperature of 140 - 160 °C for 1 hour under the protection of nitrogen to obtain a colorless transparent solution;

[0069] Step 32: After the solution is naturally cooled to 70 °C, add the core-shell nanocrystal solution obtained in Step 25 to the reaction solution in Step 31, and then keep it at 80 - 100 °C for half an hour;

[0070] Step 33: After the solution is naturally cooled to room temperature, add 8 - 12 mL of methanol solution containing 4 mmol of ammonium fluoride, and then keep it at 60 - 80 °C for half an hour;

[0071] Step 34: After all the methanol solution has evaporated, quickly raise the temperature to 290 - 310 °C, and keep it at this temperature for 100 - 120 minutes, and then naturally cool it to room temperature;

[0072] Step 35: Wash the obtained nanocrystals with a mixed solution of ethanol and cyclohexane, and dry them to obtain NaLu 0.3 Y 0.7 F4@NaLu 0.8 Bi 0.2 F4:Ba Y / Dy m @NaLu 0.3 Y 0.7 F4 afterglow material.

[0073] Example 2

[0074] A high-performance X-ray excited rare earth afterglow material, the chemical composition general formula is:

[0075] NaLu 0.3 Y 0.7 F4@NaLu 0.8 Bi 0.2 F4:Ba Y / Dy m @NaLu 0.3 Y 0.7 F4,

[0076] Its preparation method successively includes the following steps:

[0077] (1) Add 2 millimoles of sodium acetate, 0.3 millimoles of lutetium acetate, and 0.7 millimoles of yttrium acetate to a mixed solution containing 7 milliliters of oleic acid and 10 milliliters of octadecene. Under the protection of nitrogen, keep it at 150 °C for 1 hour to obtain a colorless transparent solution without water;

[0078] (2) After the solution is naturally cooled to room temperature, add 4 milliliters of methanol solution containing 4 millimoles of ammonium fluoride, and then keep it at 70 °C for half an hour;

[0079] (3) After all the methanol solution has evaporated, quickly raise the temperature to 300 °C, and keep it at this temperature for 80 minutes, and then naturally cool it to room temperature;

[0080] (4) Wash the obtained nanocrystals with a mixed solution of ethanol and cyclohexane to obtain NaLu 0.3 Y 0.7 F4 core nanocrystals, and store them in 4 milliliters of cyclohexane;

[0081] (5) Add 2 millimoles of sodium acetate, 0.61 millimoles of lutetium acetate, 0.2 millimoles of bismuth acetate, 0.15 millimoles of barium acetate, and 0.04 millimoles of dysprosium acetate to a mixed solution containing 6 milliliters of oleic acid and 8 milliliters of octadecene. Under the protection of nitrogen, keep it at 160 °C for 1 hour to obtain a colorless transparent solution without water;

[0082] (6) After the solution is naturally cooled to 70 °C, add the core nanocrystal solution obtained in step (4) to the reaction solution in step (5), and then keep it at 90 °C for half an hour;

[0083] (7) After the solution is naturally cooled to room temperature, add 8 milliliters of methanol solution containing 4 millimoles of ammonium fluoride, and then keep it at 60 °C for half an hour;

[0084] (8) After all the methanol solution has evaporated, quickly raise the temperature to 310 °C, and keep it at this temperature for 100 minutes, and then naturally cool it to room temperature;

[0085] (9) Wash the obtained nanocrystals with a mixed solution of ethanol and cyclohexane to obtain NaLu 0.3 Y0.7 F4@NaLu 0.8 Bi 0.2 F4: Ba Y / Dy m Core-shell nanocrystals, stored in 4 mL of cyclohexane;

[0086] (10) Add 2 mmol of sodium acetate, 0.3 mmol of lutetium acetate, and 0.7 mmol of yttrium acetate to a mixture of 6 mL of oleic acid and 8 mL of octadecene. Under the protection of nitrogen, keep the temperature at 160 °C for 1 hour to obtain a clear anhydrous solution;

[0087] (11) After the solution is naturally cooled to 70 °C, add the core-shell nanocrystal solution obtained in step (9) to the reaction solution in step (10), and then keep the temperature at 80 °C for half an hour;

[0088] (12) After the solution is naturally cooled to room temperature, add 12 mL of a methanol solution containing 4 mmol of ammonium fluoride, and then keep the temperature at 60 °C for half an hour;

[0089] (13) After all the methanol solution has evaporated, quickly raise the temperature to 290 °C and keep the temperature at this temperature for 120 minutes, and then naturally cool to room temperature;

[0090] (14) Wash the obtained nanocrystals with a mixture of ethanol and cyclohexane, and dry them to obtain NaLu 0.3 Y 0.7 F4@NaLu 0.8 Bi 0.2 F4: Ba Y / Dy m @NaLu 0.3 Y 0.7 F4 afterglow material.

[0091] Refer to the attached Figure 1 As shown, the NaLu 0.3 Y 0.7 F4@NaLu 0.8 Bi 0.2 F4: Ba Y / Dy m @NaLu 0.3 Y 0.7 F4 afterglow material, powder X-ray diffraction analysis shows that the product is a pure hexagonal phase.

[0092] Refer to the attached Figure 2 As shown, transmission electron microscope analysis shows that the average grain size of the product is 80 nm.

[0093] After 5 minutes of X-ray irradiation, turn off the X-ray source, and the product shows Dy 3+The characteristic transition spectral lines, including the 4f-4f transitions, are shown in the attached Figure 3 as shown.

[0094] After 5 days, the product irradiated by X-rays still has a strong emission spectrum, indicating that the afterglow time of the product is greater than 5 days, as shown in the attached Figure 4 as shown.

[0095] To prove that Bi 3+ ions can enhance the afterglow luminescence performance by improving X-ray absorption, in this embodiment, the afterglow performances of samples with different Bi 3+ ion concentrations in the intermediate layer were compared. As shown in the attached Figure 5 as shown, as the Bi 3+ ion concentration gradually increases from 0.1 (mole percentage is 10%) to 0.2, the afterglow luminescence intensity is significantly improved, indicating that doping with Bi 3+ ions can improve the afterglow performance. However, when the doping concentration of Bi 3+ ions is too high, the coordination environment of rare earth ions changes, resulting in the weakening of the afterglow performance. When the Bi 3+ ion concentration is 0.2, the afterglow performance is the strongest.

[0096] To prove the influence law of Ba 2+ ion doping on the afterglow performance, in this embodiment, the afterglow performances of samples with different Ba 2+ ion concentrations in the intermediate layer were compared. As shown in the attached Figure 6 as shown, for the system without Ba 2+ ion doping, its afterglow luminescence intensity is much lower than that of the system with Ba 2+ ion doping; as the Ba 2+ ion concentration gradually increases to 0.15 (mole percentage is 15%), the afterglow luminescence intensity is significantly improved. This is because, when Ba 2+ ions are doped in the intermediate layer, Ba 2+ ions replace Lu 3+ ions to occupy the lattice site positions. To maintain the charge balance of the system, F - ion vacancies are generated in the lattice, forming defect energy levels. These energy levels can participate in capturing secondary electrons, increasing the electron storage density of the defect states. At the same time, these energy levels can improve the energy transfer efficiency from secondary electrons to the excited state energy levels of rare earth ions, thereby significantly improving the afterglow performance. An excessive Ba 2+ ion doping concentration leads to the formation of too many defects in the lattice, and these defects will increase the non-radiative relaxation probability of rare earth ions, thus reducing the afterglow luminescence.

[0097] Rare earth ions have a rich energy level structure, and non-radiative cross relaxation processes are easily generated between activated ions. In order to further optimize the afterglow performance, the concentration of activated ions was adjusted in this embodiment. Figure 7 As shown, Dy 3+ The optimal doping concentration is 0.04 (4% molar concentration).

[0098] In order to prove the particularity of the shell structure, this example compares the Lu 3+ The influence of ion concentration on afterglow performance. Figure 8 As shown, with the Lu in the outer shell 3+ As the ion concentration gradually increased from 0.1 to 0.3, the afterglow intensity was significantly improved, indicating that NaLu 0.3 Y 0.7 The F4 shell can not only passivate the nanocrystal surface and reduce the energy transfer efficiency from activated ions to surface defects, but also tailor the interface phonon state density, further reducing the probability of non-radiative relaxation of rare earth ions, thereby improving the afterglow performance.

[0099] Example 3

[0100] In order to verify and compare the NaLu in Example 2 0.3 Y 0.7 F4@NaLu 0.8 Bi 0.2 F4:Ba Y / Dy m @NaLu 0.3 Y 0.7 F4 afterglow material has strong afterglow performance, and the NaLuF4:Dy system is designed as a comparative example.

[0101] The preparation process of NaLuF4:Dy includes the following steps:

[0102] (1) 2 mmol of sodium acetate, 0.96 mmol of lutetium acetate, and 0.04 mmol of dysprosium acetate were added to a mixture of 7 ml of oleic acid and 10 ml of octadecene, and the mixture was kept at 150° C. for 1 hour under nitrogen to obtain an anhydrous transparent solution;

[0103] (2) After the solution is cooled to room temperature, 4 ml of a methanol solution containing 4 mmol of ammonium fluoride is added, and then the solution is kept at 70°C for half an hour;

[0104] (3) After all the methanol solution has evaporated, the temperature is rapidly raised to 300°C, and kept at this temperature for 80 minutes, and then naturally cooled to room temperature;

[0105] (4) The obtained nanocrystals are washed with a mixture of ethanol and cyclohexane to obtain a NaLuF4:Dy system.

[0106] Referring to the attached Figure 9 As shown, under the same irradiation and test conditions, NaLu 0.3 Y 0.7 F4@NaLu 0.8 Bi 0.2 F4:Ba Y / Dy m @NaLu 0.3 Y 0.7 The afterglow intensity of F4 is 53 times that of the NaLuF4:Dy system.

[0107] Example 4

[0108] In order to further verify that the system designed by the present invention has good application prospects in the imaging field, an imaging experiment was carried out in this example.

[0109] Application of a high-performance X-ray excited rare earth afterglow material in the imaging field. Using the high-performance X-ray excited rare earth afterglow material prepared by the present invention to make a scintillation film, the process includes:

[0110] (1) First, mix and stir the dried sample and the pre-prepared PMMA toluene solution, where the ratio of the sample powder to the PMMA powder is 2:3;

[0111] (2) Stir thoroughly with a magnetic stirrer until the solution is clear and transparent. Then use a pipette to slowly drop the solution into a glass mold, and bubbles need to be prevented during the dropping process;

[0112] (3) After the toluene naturally volatilizes for 12 h, a uniform and transparent scintillator film is prepared.

[0113] Referring to the attached Figure 10 As shown, put a common screw in the capsule, use the afterglow material prepared by the present invention as the scintillation film, wrap it on the surface of the capsule, irradiate it with X-rays for 5 minutes, then remove the film, and the image obtained by the camera can clearly see the screw and its gear-like structure inside the capsule, which has good application prospects in the imaging field.

[0114] In addition, it should be understood that although this specification is described according to the embodiments, not every embodiment only contains an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A high-performance X-ray excited rare earth afterglow material, characterized in that, The general chemical formula is: NaLu z Y 0.7 F4@NaLu 0.8 Bi x F4:Ba Y / Dy m @NaLu z Y 0.7 F4; where x is the molar content of Bi, 0.18 ≤ x ≤ 0.25, Y is the molar content of Ba, 0.1 ≤ Y ≤ 0.2, z is the molar content of Lu, 0.25 ≤ z ≤ 0.4, m is the molar content of Dy, 0.01 ≤ m ≤ 0.

05.

2. The high-performance X-ray excited rare earth afterglow material according to claim 1, characterized in that, Said x = 0.2, Y = 0.2, z = 0.3, m = 0.

04.

3. The high-performance X-ray-excited rare-earth afterglow material according to claim 2, wherein, It includes three layers: the core layer, the intermediate layer, and the shell layer. Both the core layer and the shell layer are NaLu 0.3 Y 0.7 F4, and the intermediate layer is NaLu 0.8 Bi 0.2 F4: Ba 0.2 / Dy 0.04 , the luminescence center is located in the intermediate layer, and a large number of Dy 3+ ions are located at the interface; The core, the shell layer and the intermediate layer have different matrix components, resulting in lattice mismatch at the shell interface, reducing the binding energy of F - ions and increasing the formation probability of Frenkel defects at the interface.

4. The high-performance X-ray-excited rare-earth afterglow material according to claim 3, characterized in that, Bi is doped in the intermediate layer 3+ ions, which increases the X-ray absorption coefficient without changing the crystal structure.

5. The high-performance X-ray excited rare earth afterglow material according to claim 4, characterized in that, Intermediate layer doped with Ba 2+ ions, generating F - ion vacancies in the lattice, forming defect energy levels, improving the capture efficiency of secondary electrons and the energy transfer efficiency from secondary electrons to rare earth ions.

6. The preparation method of the high-performance X-ray-excited rare earth afterglow material according to claim 1, characterized in that, It includes the following steps: Step 1: Prepare NaLu 0.3 Y 0.7 F4 core nanocrystals; Step 2: Using the core nanocrystals in Step 1, prepare NaLu 0.3 Y 0.7 F4@NaLu 0.8 Bi 0.2 F4: Ba Y / Dy m core-shell nanocrystals Step 3: Prepare NaLu using the core-shell nanocrystals in Step 2 0.3 Y 0.7 F4@NaLu 0.8 Bi 0.2 F4: Ba Y / Dy m @NaLu 0.3 Y 0.7 F4 afterglow materials.

7. The preparation method of the high-performance X-ray excited rare earth afterglow material according to claim 6, characterized in that, The preparation steps of the core nanocrystals include: Step 11: Add 2 mmol of sodium acetate, 0.3 mmol of lutetium acetate, and 0.7 mmol of yttrium acetate in molar percentages to a mixed solution containing 6 - 8 mL of oleic acid and 8 - 10 mL of octadecene. Under the protection of nitrogen, keep it at a temperature of 140 - 160 °C for 1 hour to obtain an anhydrous transparent solution; Step 12: After the solution is naturally cooled to room temperature, add 4 - 6 mL of a methanol solution containing 4 mmol of ammonium fluoride, and then keep it at 60 - 90 °C for half an hour; Step 13: After all the methanol solution has evaporated, quickly raise the temperature to 290 - 310 °C, and keep it at this temperature for 80 - 100 minutes, and then naturally cool it to room temperature; Step 14: Wash the obtained nanocrystals with a mixed solution of ethanol and cyclohexane to obtain NaLu 0.3 Y 0.7 F4 core nanocrystals, and store them in 4 - 6 mL of cyclohexane.

8. The preparation method of the high-performance X-ray excited rare earth afterglow material according to claim 7, characterized in that, The preparation steps of the core - shell nanocrystals include: Step 21: Add 2 mmol of sodium acetate, 0.55 - 0.69 mmol of lutetium acetate, 0.2 mmol of bismuth acetate, 0.1 - 0.2 mmol of barium acetate, and 0.01 - 0.05 mmol of dysprosium acetate in molar percentages to a mixed solution containing 6 - 8 mL of oleic acid and 8 - 12 mL of octadecene. Under the protection of nitrogen, keep it at a temperature of 140 - 160 °C for 1 hour to obtain an anhydrous transparent solution; Step 22: After the solution is naturally cooled to 70 °C, add the core nanocrystal solution obtained in Step 14 to the reaction solution in Step 21, and then keep it at 80 - 100 °C for half an hour; Step 23: After the solution is naturally cooled to room temperature, add 8 - 12 mL of a methanol solution containing 4 mmol of ammonium fluoride, and then keep it at 60 - 80 °C for half an hour; Step 24: After all the methanol solution has evaporated, quickly raise the temperature to 290 - 310 °C, and keep it at this temperature for 90 - 130 minutes, and then naturally cool it to room temperature; Step 25: Wash the obtained nanocrystals with a mixed solution of ethanol and cyclohexane to obtain NaLu 0.3 Y 0.7 F4@NaLu 0.8 Bi 0.2 F4:Ba Y / Dy m core-shell nanocrystals, and store them in 4 - 6 mL of cyclohexane.

9. The preparation method of the high-performance X-ray-excited rare earth afterglow material according to claim 8, characterized in that, The preparation steps of the rare - earth afterglow material include: Step 31: Add 2 mmol of sodium acetate, 0.3 mmol of lutetium acetate, and 0.7 mmol of yttrium acetate in molar percentages to a mixed solution containing 6 - 8 mL of oleic acid and 8 - 10 mL of octadecene. Under the protection of nitrogen, keep it at a temperature of 140 - 160 °C for 1 hour to obtain an anhydrous transparent solution; Step 32: After the solution is naturally cooled to 70 °C, add the core - shell nanocrystal solution obtained in Step 25 to the reaction solution in Step 31, and then keep it at 80 - 100 °C for half an hour; Step 33: After the solution is naturally cooled to room temperature, add 8 - 12 mL of a methanol solution containing 4 mmol of ammonium fluoride, and then keep it at 60 - 80 °C for half an hour; Step 34: After all the methanol solution has evaporated, quickly raise the temperature to 290 - 310 °C, and keep it at this temperature for 100 - 120 minutes, and then naturally cool it to room temperature; Step 35: Wash the obtained nanocrystals with a mixed solution of ethanol and cyclohexane, and dry them to obtain NaLu 0.3 Y 0.7 F4@NaLu 0.8 Bi 0.2 F4: Ba Y / Dy m @NaLu 0.3 Y 0.7 F4 afterglow material.

10. Use of a high-performance X-ray-excited rare-earth afterglow material prepared by the method according to claim 9 in the field of imaging.

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