High-performance single rare earth doped fluoride, flexible scintillation screen and application

Abstract

The invention discloses a high-performance single rare earth doped fluoride, a flexible scintillation screen and application. The single rare earth doped fluoride is Cs (1-x) NaxLu (2-y) LnyF7, wherein x < lt > is greater than or equal to 0.3; 0.4, Ln is Tb, Dy or Pr; the single rare earth doped fluoride is prepared by a thermal decomposition method, the single rare earth doped fluoride can be uniformly mixed with a prepolymer solution of a substrate and then subjected to spin coating and drying to obtain the flexible scintillation screen, and the flexible scintillation screen is used for X-ray high-resolution delayed imaging of an object. The invention provides the fluoride scintillator with single ion doping, simple structure, controllable shape and strong XEOL and XEPL, the manufacturing process is simple, and the minimum number of fluoride scintillator particles can be used for manufacturing a flexible scintillation screen based on a thin film, so that high-resolution flexible delay non-planar imaging capable of responding to X rays is realized.

Description

Technical Field

[0001] The invention belongs to the technical field of luminescent materials, and in particular relates to a high-performance single rare earth doped fluoride, a flexible scintillating screen and applications thereof. Background Art

[0002] After rare earth ion doped fluoride is excited by X-rays, the X-ray photons can interact with the matrix lattice through the photoelectric effect and Compton scattering to generate hot electrons and deep holes, and then generate a large number of low kinetic energy carriers through electron-electron scattering and Auger process. These carriers are easily captured by the Frank defects generated in the material after X-ray excitation, thus producing afterglow after the X-ray excitation is turned off.

[0003] X-ray imaging technology can be used in a wide range of applications, such as accurate medical diagnosis, automatic security inspection, electronic component detection, and biological specimen detection. Lanthanide-doped fluoride nanoparticles can be used as a universal and superior X-ray delayed imaging scintillator due to their low cytotoxicity, excellent stability, easily controllable size, and excellent X-ray excitation luminescence / persistent luminescence. However, although many excellent lanthanide-doped fluoride scintillators have been reported as X-ray imaging detectors, there are still some limitations. First, in order to achieve high-resolution imaging, the activator needs to have very strong excitation luminescence / persistent luminescence emission, which often requires further precise introduction of sensitizing ions or alivalent ions and appropriate adjustment of their doping concentration, which increases the complexity of experimental design; second, some complex core / shell / shell structures need to be designed to amplify the excitation luminescence / persistent luminescence intensity, but the continuous growth of the shell layer requires a time-consuming experimental process; finally, for the current generation of X-ray imaging scintillator screens, most reports focus on planar imaging, which is limited to imaging of planar electronic components or materials with planar tendencies.

[0004] To date, it has been a significant challenge to develop a lanthanide-doped fluoride scintillator that is simple to fabricate, structurally simple, and has strong excitation luminescence / persistent luminescence, and enables high-resolution flexible delayed nonplanar imaging. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention provides a high-performance single rare earth doped fluoride, a flexible scintillator screen and its application. The present invention provides a fluoride scintillator with single ion doping, simple structure, controllable shape, strong X-ray excited luminescence (XEOL) and X-ray excited sustained luminescence (XEPL), simple manufacturing process, and the minimum amount of fluoride scintillator particles can be used to manufacture a thin film-based flexible scintillator screen, thereby realizing high-resolution flexible delayed non-planar imaging that can respond to X-rays.

[0006] The technical solution of the present invention is as follows:

[0007] 1. A high-performance single rare earth doped fluoride

[0008] The single rare earth doped fluoride is Cs 1-x Na x Lu 2-y Ln y F7, 0.3≤x<0.4, Ln represents a rare earth element, Ln is Tb, Dy or Pr; when the rare earth element Ln is Tb, 0.1≤y≤0.18, when the rare earth element Ln is Dy, y=0.05, when the rare earth element Ln is Pr, y=0.05.

[0009] The single rare earth doped fluoride can achieve scintillation luminescence in the wavelength range of 490 nanometers to 620 nanometers under X-ray excitation; after the X-ray excitation stops, the single rare earth doped fluoride can exhibit luminescence afterglow in the wavelength range of 490 nanometers to 620 nanometers, and the luminescence afterglow lasts for at least thirty minutes.

[0010] The grain size distribution range of the single rare earth doped fluoride is 23-27 nm.

[0011] The single rare earth doped fluoride is composed of rare earth ions Ln 3+ The single dopant acts as a luminescence center and exhibits strong scintillation luminescence and sustained luminescence after X-ray excitation.

[0012] 2. A method for preparing high performance single rare earth doped fluoride

[0013] The following steps are involved:

[0014] 1) mixing cesium oxide, sodium oxide, lutetium oxide or rare earth oxide with a co-solvent respectively to obtain a rare earth trifluoroacetate mixture, a cesium trifluoroacetate mixture, a sodium trifluoroacetate mixture and a lutetium trifluoroacetate mixture;

[0015] 2) adding a cesium trifluoroacetate mixture, a lutetium trifluoroacetate mixture and a rare earth trifluoroacetate mixture to the oleic acid-octadecene solution, and heating to remove water to obtain a solution A; the ratio of the total molar amount of the lutetium trifluoroacetate and the rare earth trifluoroacetate to the volume of the oleic acid-octadecene solution is 2 mmol: 10 mL to 20 mL;

[0016] Adding a sodium trifluoroacetate mixture to the oleic acid-octadecene solution, heating and removing water to obtain a solution B;

[0017] 3) heating the oleic acid-octadecene solution to remove water to obtain solution C; then heating solution C to 300-310° C. under an inert gas atmosphere;

[0018] 4) When solution C is heated to 300-310°C, solution A is injected into solution C at a constant rate and reacted at 300-310°C for 50-60 minutes;

[0019] 5) injecting solution B into solution C after solution A was injected at a constant rate, reacting at 300-310° C. for 80-90 min, and then cooling to room temperature;

[0020] 6) After the solution cooled to room temperature is centrifuged to obtain a precipitate, it is subsequently washed with a mixed solution of ethanol and cyclohexane, centrifuged and dried at 60-70° C. to obtain the single rare earth doped fluoride.

[0021] In the step 2), the process and conditions of heating to remove water are specifically as follows: heating the solution to be heated to remove water to 140-150° C., maintaining the temperature at 140-150° C. for 90-120 minutes to remove water, and then cooling to room temperature.

[0022] In the step 3), the heating and water removal process and conditions are as follows: heating the oleic acid-octadecene solution to 120-140° C. and maintaining the temperature at 120-140° C. for 60-90 minutes to remove water.

[0023] In the step 4), the injection rate of solution A is 1.25 mL / min to 2 mL / min; in the step 5), the injection rate of solution B is 1.25 mL / min to 2 mL / min.

[0024] 3. A flexible flashing screen

[0025] The flexible scintillator screen is mainly composed of a substrate and a luminous scintillator loaded inside the substrate.

[0026] The luminescent scintillator adopts the high-performance single rare earth doped fluoride.

[0027] The flexible scintillating screen is mainly formed by mixing a luminescent scintillator, an organic solvent and a prepolymer solution of a substrate in a mass ratio of 0.7 to 1.1:1:10, followed by spin coating and drying.

[0028] 4. Application of a flexible flashing screen

[0029] The flexible scintillating screen is mainly used for X-ray high-resolution imaging of objects.

[0030] The imaging includes one of real-time planar imaging, real-time non-planar imaging, delayed planar imaging and delayed non-planar imaging.

[0031] The thickness of the flexible scintillating screen is 0.9-1.2 mm, and it emits light under X-ray excitation, with a radioluminescence wavelength of 490-620 nm and a maximum spatial resolution of 16.1 lp mm-1 .

[0032] After being irradiated by X-rays, the flexible scintillating screen is first subjected to heat treatment and then to delayed imaging; the conditions of the heat treatment are: heating for 30 to 40 minutes at an ambient temperature of 60 to 70°C.

[0033] The high-performance single rare earth doped fluoride flexible scintillator absorbs the X-rays emitted by the radiation source and converts them into strong visible light; after the X-rays of the radiation source are turned off, the high-performance single rare earth doped fluoride flexible scintillator emits strong and long-lasting light; the high-performance single rare earth doped fluoride flexible scintillator contains at least the Cs 1-x Na x Lu 2-y Tb y F7 (Ln is one of Tb, Dy and Pr); the high-performance single rare earth doped fluoride flexible scintillator screen has high surface flatness, good environmental stability and high transparency. It can perform high-resolution delayed imaging of the interior of non-planar objects.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] 1. Cs provided by the present invention 1-x Na x Lu 2-y Ln y F7 (Ln is Tb, Dy and Pr) scintillator is composed of rare earth ions Ln 3+ As the luminescence center, single doping does not require the introduction of sensitizing ions, heterovalent ions, and complex core-shell structures to produce strong scintillation luminescence and sustained luminescence after X-ray excitation. Its physical and chemical properties are very stable and its preparation method is fast and simple.

[0036] 2. Cs provided by the present invention 1-x Na x Lu 2-y Ln y The F7 (Ln is Tb, Dy and Pr) scintillator can excite deep traps after heating, thereby significantly enhancing the sustained luminescence intensity, enhancing the luminescence ability of the scintillator and the imaging ability of the subsequent prepared scintillator screen.

[0037] 3. The present invention provides a Cs-based 1-x Na x Lu 2-y Ln y The flexible scintillator screen of F7 (Ln is Tb, Dy and Pr) scintillator can use the minimum amount of particles to manufacture the flexible scintillator screen based on the thin film, so that the flexible scintillator screen has high surface flatness, good environmental stability and high transparency.

[0038] 4. The present invention provides a Cs-based 1-x Na x Lu 2-y Ln y The flexible scintillator screen of F7 (Ln is Tb, Dy and Pr) scintillator can perform high-resolution delayed imaging of the interior of non-planar objects, and its imaging spatial resolution is as high as 16.1lp mm -1 , which is much higher than medical CT scan (2lp mm -1 ) and X-ray imaging (3.5lp mm -1 )The typical spatial resolution required.

[0039] 5. The present invention provides a Cs-based 1-x Na x Lu 2-y Ln y The flexible scintillator screen with F7 (Ln is Tb, Dy and Pr) scintillator has a simple manufacturing process, low cost and can be mass-produced in a short time. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 Cs in Example 1 of the present invention 0.7 Na 0.3 Lu 1.85 Tb 0.15 X-ray diffraction spectrum of F7 scintillator;

[0041] Figure 2 Cs in Example 1 of the present invention 0.7 Na 0.3 Lu 1.85 Tb 0.15 Transmission electron micrograph of F7 scintillator;

[0042] Figure 3 Cs in Example 1 of the present invention 0.7 Na 0.3 Lu 1.85 Tb 0.15 Continuous luminescence spectrum of F7 scintillator;

[0043] Figure 4 Cs in Example 1 of the present invention 0.7 Na 0.3 Lu 1.85 Tb 0.15 Comparison of the scintillation intensity of F7 scintillation and commercial scintillators;

[0044] Figure 5 Cs in Example 1 of the present invention 0.7 Na 0.3 Lu 1.85 Tb 0.15Comparison of the sustained luminescence intensity of F7 and the common fluoride NaYF4:Tb@NaYF4:Tb scintillator;

[0045] Figure 6 Cs in Example 1 of the present invention 0.7 Na 0.3 Lu 1.85 Tb 0.15 The continuous luminous intensity of F7 scintillator changes with time and the spectrum after heat treatment;

[0046] Figure 7 is Cs in Example 2 of the present invention 0.7 Na 0.3 Lu 1.95 Dy 0.05 F7 scintillator continuous luminescence spectrum;

[0047] Figure 8 is Cs in Example 3 of the present invention 0.7 Na 0.3 Lu 1.95 Pr 0.05 F7 scintillator continuous luminescence spectrum;

[0048] Fig. 9 The present invention is based on Cs in Example 1 0.7 Na 0.3 Lu 1.85 Tb 0.15 Physical picture of the flexible scintillator screen made of F7 scintillator;

[0049] Fig.10 The present invention is based on Cs in Example 1 0.7 Na 0.3 Lu 1.85 Tb 0.15 Flexible effect diagram of the flexible scintillator screen made of F7 scintillator;

[0050] Fig.11 The present invention is based on Cs in Example 1 0.7 Na 0.3 Lu 1.85 Tb 0.15 Real-time X-ray images of standard X-ray resolution of flexible scintillator screen made of F7 scintillator;

[0051] Fig.12 The present invention is based on Cs in Example 1 0.7 Na 0.3 Lu 1.85 Tb 0.15 Non-planar imaging effect diagram of the flexible scintillator screen made of F7 scintillator. DETAILED DESCRIPTION

[0052] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0053] A first aspect of the present invention provides a single rare earth doped fluoride.

[0054] The molecular formula of the single rare earth doped fluoride provided by the present invention is Cs 1-x Na x Lu 2-y Ln y F7.

[0055] Wherein, 0.3≤x<0.4. x is preferably 0.3, 0.35 or 0.38, and most preferably 0.3.

[0056] Wherein, Ln represents a rare earth element, and Ln is Tb, Dy or Pr.

[0057] The value of y depends on the element type of Ln:

[0058] When the rare earth element Ln is Tb, 0.1≤y≤0.18;

[0059] When the rare earth element Ln is Dy, y = 0.05;

[0060] When the rare earth element Ln is Pr, y=0.05.

[0061] The single rare earth doped fluoride provided by the present invention is a rare earth ion Ln 3+ As the luminescent center, the single doping has strong scintillation luminescence and continuous luminescence after X-ray excitation. Specifically, under X-ray excitation, the single rare earth doped fluoride can achieve scintillation luminescence in the wavelength range of 490 nanometers to 620 nanometers; after the X-ray excitation stops, the single rare earth doped fluoride can show luminescence afterglow in the wavelength range of 490 nanometers to 620 nanometers, and the luminescence afterglow lasts for at least thirty minutes, and the duration of the luminescence afterglow can reach more than 300 minutes.

[0062] The grain size distribution range of the single rare earth doped fluoride provided by the present invention is 23-27 nm. Within this range, the single rare earth doped fluoride can exert the best luminescence performance.

[0063] The present invention further provides a method for preparing a single rare earth doped fluoride. The single rare earth doped fluoride provided by the present invention can be prepared by a thermal decomposition method. Specifically, the method comprises the following steps:

[0064] 1) mixing cesium oxide, sodium oxide, lutetium oxide or rare earth oxide with a co-solvent respectively to obtain a rare earth trifluoroacetate mixture, a cesium trifluoroacetate mixture, a sodium trifluoroacetate mixture and a lutetium trifluoroacetate mixture;

[0065] In step 1), the cosolvent is a mixed aqueous solution of trifluoroacetic acid; the mass percentages of the oxide and trifluoroacetic acid in the mixed aqueous solution are 5% to 10% and 25% to 50% respectively; the oxide is cesium oxide, sodium oxide, lutetium oxide or rare earth oxide. In a specific implementation, the mass percentages of the oxide and trifluoroacetic acid in the mixed aqueous solution can be adjusted according to the type of oxide.

[0066] 2) adding a cesium trifluoroacetate mixture, a lutetium trifluoroacetate mixture and a rare earth trifluoroacetate mixture to 1 volume fraction of an oleic acid-octadecene solution (the volume ratio of oleic acid to octadecene is 1:1), and heating to remove water to obtain a solution A; adding a sodium trifluoroacetate mixture to 1 volume fraction of an oleic acid-octadecene solution (the volume ratio of oleic acid to octadecene is 1:1), and heating to remove water to obtain a solution B;

[0067] In step 2), the process and conditions of heating to remove water are specifically as follows: heating the solution to be heated to remove water to 140-150° C., maintaining the temperature at 140-150° C. for 90-120 minutes to remove water, and then cooling to room temperature.

[0068] 3) heating 1 volume portion of oleic acid-octadecene solution (the volume ratio of oleic acid to octadecene is 1:1) to remove water to obtain solution C; then heating solution C to 300-310° C. under an inert gas atmosphere;

[0069] In step 3), the heating and dehydration process and conditions are as follows: heating the oleic acid-octadecene solution to 120-140° C. and maintaining the temperature at 120-140° C. for 60-90 minutes to remove moisture.

[0070] 4) When solution C is heated to 300-310°C, solution A is injected into solution C at a constant rate of 1.25 mL / min-2 mL / min, and the reaction is carried out at 300-310°C for 50-60 min;

[0071] 5) injecting solution B into solution C after solution A was injected at a constant rate of 1.25 mL / min to 2 mL / min, reacting at 300 to 310° C. for 80 to 90 min, and then cooling to room temperature;

[0072] In a specific implementation, the injection rates of solution A and solution B are both related to the luminescent effect of the material. Outside this injection rate range, too fast or too slow will cause the nanoparticles to be small in size and agglomerated or too large in size and uneven.

[0073] 6) The precipitate is collected by filtration or centrifugation, and then washed with a mixed solution of ethanol and cyclohexane (the volume ratio of ethanol to cyclohexane is generally 3:1), centrifuged and dried at 60° C. to obtain a single rare earth doped fluoride.

[0074] A second aspect of the present invention provides a flexible scintillation screen.

[0075] The flexible scintillator provided by the present invention is mainly composed of a substrate and a luminescent scintillator loaded inside the substrate, wherein the luminescent scintillator adopts the high-performance single rare earth doped fluoride provided by the present invention.

[0076] The flexible scintillating screen provided by the invention is mainly formed by mixing a luminescent scintillator, an organic solvent and a prepolymer solution of a substrate in a mass ratio of 0.7 to 1.1:1:10, followed by spin coating and drying.

[0077] The prepolymer solution of the substrate contains a substrate binder and a cross-linking agent.

[0078] Preferably, the base material of the substrate is polydimethylsiloxane, and the prepolymer solution of the substrate is mainly formed by mixing a cross-linking agent and polydimethylsiloxane (PDMS) in a mass ratio of 1:10.

[0079] A third aspect of the present invention provides an application of a flexible scintillating screen in X-ray high-resolution imaging of an object.

[0080] In the application provided by the present invention, the imaging mode includes one of real-time planar imaging, real-time non-planar imaging, delayed planar imaging and delayed non-planar imaging.

[0081] When the flexible scintillator screen is used for X-ray high-resolution imaging of an object, the thickness of the flexible scintillator screen is preferably 0.9 to 1.2 mm. The flexible scintillator screen emits light under X-ray excitation, the radioluminescence wavelength is 490 to 620 nm, and the maximum spatial resolution is 16.1 lp mm -1 .

[0082] The application provided by the present invention also includes: the flexible scintillating screen is subjected to delayed imaging after being irradiated with X-rays and heat-treated. The delayed imaging is delayed planar imaging or delayed non-planar imaging. The heat-treatment conditions are: heating at an ambient temperature of 60 to 70° C. for 30 to 40 minutes.

[0083] The specific embodiments of the present invention are as follows:

[0084] The spectral data in the embodiments of the present invention are all obtained by excitation with a micro X-ray excitation source of the OmniFluo-Xray-JL system (PMT-CR131-TE detector, 185-900nm), the spectrum acquisition range is 300-800nm, and the power of the X-ray is 3-12W. Unless otherwise specified, the continuous luminescence spectra in the embodiments of the present invention are all irradiated with 10W X-rays for 5 minutes, and the test is started after stopping the excitation for 10s.

[0085] Example 1

[0086] In this example, single rare earth doped fluoride Cs was prepared by thermal decomposition. 0.7 Na 0.3 Lu 1.85 Tb 0.15 F7, and using the prepared single rare earth doped fluoride Cs 0.7 Na 0.3 Lu 1.85 Tb 0.15 F7 and polydimethylsiloxane (PDMS) were used to prepare a thin film-based flexible scintillating screen, thereby achieving high-resolution flexible delayed non-planar X-ray imaging.

[0087] In this embodiment, the single rare earth doped fluoride Cs 0.7 Na 0.3 Lu 1.85 Tb 0.15 The specific preparation process of F7 is as follows:

[0088] 1) First, terbium oxide is added to a flux of a certain weight percentage, and fully ground or stirred to obtain a terbium trifluoroacetate mixture. 0.7 Na 0.3 Lu 1.85 Tb 0.15 The desired trifluoroacetate salts are weighed or prepared in a stoichiometric ratio of F7 to obtain a cesium trifluoroacetate mixture, a sodium trifluoroacetate mixture and a lutetium trifluoroacetate mixture.

[0089] 2) In a three-necked flask A with a volume of 100 mL, a cesium trifluoroacetate mixture (comprising 0.4 mmol cesium trifluoroacetate Cs-TFA), a lutetium trifluoroacetate mixture (comprising 1.85 mmol lutetium trifluoroacetate Lu-TFA) and a terbium trifluoroacetate mixture (comprising 0.15 mmol terbium trifluoroacetate Tb-TFA), oleic acid OA (5 mL) and octadecene ODE (5 mL) were mixed. Meanwhile, in another three-necked flask B with a volume of 100 mL, a sodium trifluoroacetate mixture (comprising 0.6 mmol sodium trifluoroacetate Na-TFA), oleic acid OA (5 mL) and octadecene ODE (5 mL) were mixed.

[0090] Then, three-necked flask A and three-necked flask B were heated to 140° C., respectively, maintained at 140° C. for 90 min to remove moisture, and then cooled to room temperature to obtain solution A and solution B.

[0091] Solution A and solution B are transferred to syringe A and syringe B respectively. Syringe A and syringe B are both 10 mL in size.

[0092] 3) adding oleic acid OA (5 mL) and octadecene ODE (5 mL) into a three-necked flask C with a volume of 100 mL, then heating the three-necked flask C to 120° C. and maintaining the temperature at 120° C. for 60 min to remove moisture, thereby obtaining a solution C;

[0093] Then, under N2 atmosphere, solution C in three-necked flask C was heated to 300°C;

[0094] 4) When solution C is heated to 300°C, solution A in syringe A is injected into three-necked flask C at a rate of 1.5 mL / min and reacted at 300°C for 60 min;

[0095] 5) Solution B in syringe B was then injected into three-necked flask C at 1.5 mL / min, followed by reaction at 300° C. for 90 min and then cooled to room temperature;

[0096] 6) After the solution cooled to room temperature is centrifuged to obtain the precipitate, it is washed again with a mixed solution of ethanol and cyclohexane, centrifuged and dried at 60° C. to obtain a single rare earth doped fluoride Cs 0.7 Na 0.3 Lu 1.85 Tb 0.15 F7.

[0097] Attached Figure 1 is the Cs obtained in this example 0.7 Na 0.3 Lu 1.85 Tb 0.15 X-ray diffraction spectrum of F7 scintillator. Figure 1 It can be seen that Cs 0.7 Na 0.3 Lu 1.85 Tb 0.15 The F7 scintillator matches well with the standard card PDF-43-0504, and the main crystal lattice of the luminescent material belongs to the hexagonal system.

[0098] Attached Figure 2 is the Cs obtained in this example 0.7 Na 0.3 Lu 1.85 Tb 0.15 Transmission electron micrograph of F7 scintillator. Figure 2 It can be seen that the Cs obtained in this embodiment 0.7 Na 0.3 Lu 1.85 Tb 0.15 The grain size of F7 scintillator is normally distributed between 23 and 27 nm.

[0099] Attached Figure 3This is the continuous luminescence emission spectrum of the scintillator in this embodiment after the excitation source X-ray irradiation is turned off for a period of time. Figure 3 It can be seen that the flashing and continuous luminescence of the scintillator are both visible green light, with main peak wavelengths of 490nm, 540nm, 585nm and 620nm.

[0100] Attached Figure 4 The following is a comparison of the scintillation intensity of the scintillator in this embodiment and the commercial scintillator after irradiation with X-rays of the same power. The commercial scintillator refers to cesium iodide doped with thallium (CSI:TI) and bismuth germanate (BGO) obtained by commercial means. Figure 4 It can be seen that the scintillator of this embodiment has obvious advantages in scintillation and luminescence compared with commercial scintillators.

[0101] Attached Figure 5 This is a comparison chart of the sustained luminescence intensity of the scintillator of this embodiment and the common fluoride NaYF4:Tb@NaYF4:Tb scintillator. Figure 5 It can be seen that the scintillator of this embodiment has a more obvious continuous luminescence advantage compared with the common fluoride scintillator.

[0102] In this embodiment, the obtained single rare earth doped fluoride was irradiated with X-rays of the same power and then heated at 65°C for 30 minutes to obtain heat-treated single rare earth doped fluoride. 0.7 Na 0.3 Lu 1.85 Tb 0.15 F7 and thermally treated single rare earth doped fluoride Cs 0.7 Na 0.3 Lu 1.85 Tb 0.15 The continuous luminous intensity of F7 was tested, and the results are attached. Figure 6 It can be seen that the single rare earth doped fluoride Cs obtained in this embodiment 0.7 Na 0.3 Lu 1.85 Tb 0.15 The continuous luminescence time of F7 can reach 300 minutes. Moreover, after heat treatment, the single rare earth doped fluoride Cs 0.7 Na 0.3 Lu 1.85 Tb 0.15 The sustained luminous intensity of F7 has been further improved.

[0103] In this embodiment, by repeating the above process, multiple single rare earth doped fluoride Cs 0.7 Na 0.3 Lu 1.85 Tb 0.15F7. Then the prepared single rare earth doped fluoride Cs 0.7 Na 0.3 Lu 1.85 Tb 0.15 F7 was used as a scintillator and polydimethylsiloxane (PDMS) to prepare a thin film-based flexible scintillating screen.

[0104] The specific preparation process of the flexible scintillating screen is as follows: 180 mg of single rare earth doped fluoride and organic solvent chloroform (CHCl3) are mixed in a mass ratio of 1:1, stirred at room temperature for 30 minutes, and then 1.2 g of polydimethylsiloxane prepolymer solution (the weight ratio of prepolymer and cross-linking agent is 10:1) is added, and ultrasonicated for 60 minutes to obtain a precursor solution of the flexible scintillating screen; the precursor solution of the flexible scintillating screen is spin-coated on a 30 mm × 30 mm × 3 mm mold at 5000 rpm, and dried at 80°C for 24 hours to obtain a film-based flexible scintillating screen.

[0105] Attached Fig. 9 The Cs 0.7 Na 0.3 Lu 1.85 Tb 0.15 The actual picture of the flexible scintillator screen made of F7 scintillator. Fig. 9 It can be seen that the flexible scintillating screen obtained in this embodiment has high transparency and flatness.

[0106] Attached Fig.10 The Cs 0.7 Na 0.3 Lu 1.85 Tb 0.15 The flexible effect diagram of the flexible scintillator screen made of F7 scintillator. Fig.10 It can be seen that the flexible scintillating screen obtained in this embodiment can still maintain its original properties after being bent and stretched.

[0107] In this embodiment, the film-based flexible scintillating screen is used to achieve X-ray high-resolution flexible delayed non-planar imaging.

[0108] The specific process of the imaging process is as follows: the prepared flexible scintillating screen is placed under the imaging object and wraps the imaging object, and the imaging object is irradiated with X-rays from above. The rays pass through the object and the scintillating screen and are converted into visible light, which is captured and imaged by the subsequent camera. The power of the X-rays and the imaging light emitted by the scintillating screen are directly proportional but nonlinear.

[0109] Attached Fig.11 The standard X-ray resolution real-time X-ray image is obtained by using the flexible scintillating screen obtained in this embodiment. The imaging light of the real-time X-ray image is the scintillation light of the flexible scintillating screen after being irradiated. Fig.11It can be seen that the imaging spatial resolution of the flexible scintillation screen obtained in this embodiment can reach 16.1 lp mm -1 , much higher than medical CT scan (2lpmm -1 ) and X-ray imaging (3.5lp mm -1 )The typical spatial resolution required.

[0110] Attached Fig.12 This is a non-planar imaging effect diagram obtained by using the flexible scintillating screen obtained in this embodiment. This imaging light is the continuous light emitted by the flexible scintillating screen after the radiation stops. Fig.12 It can be seen that the flexible scintillating screen obtained in this embodiment can be used for non-planar imaging.

[0111] The present invention prepares single rare earth doped fluorides with different rare earth elements and different stoichiometric ratios according to the same process as in Example 1. The chemical formula and luminescence properties of the single rare earth doped fluorides prepared in each example and comparative example are shown in the following table:

[0112]

[0113] The continuous luminescence spectrum integration is performed in the wavelength range of 400 to 700 nm.

[0114] After irradiating the single rare earth doped fluoride obtained in Example 2 and Example 3 of the present invention with 10W X-ray for 5 minutes, the emission spectrum was tested 10 seconds after the excitation was stopped, and the continuous luminescence emission spectrum of Example 2 to Example 3 after the excitation source X-ray irradiation was turned off for a period of time was obtained, as shown in the attached drawings. Figure 7 , Attachment Figure 8 . It can be seen that when the rare earth element is Dy, the luminescence peaks are 481nm and 571nm. When the rare earth element is Pr, the luminescence peaks are 483nm and 607nm. Comparing Examples 1 to 3, it can be seen that the scintillation light and continuous luminescence of the high-performance single rare earth doped fluoride obtained by the present invention and the flexible scintillation screen based on the high-performance single rare earth doped fluoride after irradiation depend on the doping ion Ln 3+ :

[0115] When doped with ions Ln 3+ Tb 3+ When irradiated, the flashing light and continuous luminescence are visible green light;

[0116] When doped with ions Ln 3+ For Dy 3+ When irradiated, the flashing light and continuous luminescence are visible blue light;

[0117] When doped with ions Ln 3+ Pr 3+When irradiated, the flashing light and continuous glow are visible red light.

[0118] Comparing Example 1, Example 4 to Example 5 and Comparative Example 1 to Comparative Example 4, it can be seen that when the doping ion Ln 3+ Tb 3+ When x is within the range of 0.3≤x<0.4, high-performance single rare earth doped fluorides have better performance and better continuous luminescence effect.

[0119] Comparing Example 1, Example 6 to Example 8 and Comparative Example 5 to Comparative Example 6, it can be seen that when the doping ion Ln 3+ Tb 3+ When y is within the range of 0.1≤y≤0.18, high-performance single rare earth doped fluorides have better performance and better continuous luminescence effect.

[0120] Comparing Example 2, Example 3 and Comparative Example 7, Comparative Example 8, it can be seen that when the doping ion Ln 3+ For Dy 3+ and Pr 3+ When y=0.05, the performance of high-performance single rare earth doped fluoride is better and the continuous luminescence effect is better.

[0121] In summary, the Cs obtained by the present invention 1-x Na x Lu 2-y Ln y The F7 scintillator can achieve excellent sustained luminescence with the simplest structure and single activated particle doping. When the value range of x is: 0.3≤x<0.4, and when Ln is Tb, 0.1≤y≤0.18, when Ln is Dy, y=0.05, when Ln is Pr, y=0.05, the sustained luminescence effect is better.

[0122] In summary, the present invention has a simple preparation process and good imaging effect, and can be widely used in detection, biology, medical treatment and other fields.

[0123] Obviously, the above embodiments are merely examples for the purpose of clear description, and other changes or modifications may be made based on the above description. Therefore, obvious changes or modifications derived therefrom still fall within the protection scope of the present invention.

Claims

1. A high performance single rare earth doped fluoride, characterized in that: The single rare earth doped fluoride is Cs 1-x Na x Lu 2- y Ln y F7, 0.3≤x<0.4, Ln represents a rare earth element, Ln is Tb, Dy or Pr; when the rare earth element Ln is Tb, 0.1≤y≤0.18, when the rare earth element Ln is Dy, y=0.05, when the rare earth element Ln is Pr, y=0.

05.

2. The high performance single rare earth doped fluoride according to claim 1, characterized in that: Under X-ray excitation, the single rare earth doped fluoride realizes scintillation luminescence in the wavelength range of 490 nanometers to 620 nanometers; after the X-ray excitation stops, the single rare earth doped fluoride exhibits luminescence afterglow in the wavelength range of 490 nanometers to 620 nanometers, and the luminescence afterglow lasts for more than thirty minutes.

3. The high performance single rare earth doped fluoride according to claim 1, characterized in that: The grain size distribution range of the single rare earth doped fluoride is 23-27 nm.

4. A method for preparing a high-performance single rare earth doped fluoride according to any one of claims 1 to 3, characterized in that: The following steps are involved: 1) mixing cesium oxide, sodium oxide, lutetium oxide or rare earth oxide with a co-solvent respectively to obtain a rare earth trifluoroacetate mixture, a cesium trifluoroacetate mixture, a sodium trifluoroacetate mixture and a lutetium trifluoroacetate mixture; 2) adding a cesium trifluoroacetate mixture, a lutetium trifluoroacetate mixture and a rare earth trifluoroacetate mixture to the oleic acid-octadecene solution, and heating to remove water to obtain a solution A; the ratio of the total molar amount of the lutetium trifluoroacetate and the rare earth trifluoroacetate to the volume of the oleic acid-octadecene solution is 2 mmol: 10 mL to 20 mL; Adding a sodium trifluoroacetate mixture to the oleic acid-octadecene solution, heating and removing water to obtain a solution B; 3) heating the oleic acid-octadecene solution to remove water to obtain solution C; then heating solution C to 300-310° C. under an inert gas atmosphere; 4) When solution C is heated to 300-310°C, solution A is injected into solution C at a constant rate and reacted at 300-310°C for 50-60 minutes; 5) injecting solution B into solution C after solution A was injected at a constant rate, reacting at 300-310° C. for 80-90 min, and then cooling to room temperature; 6) After the solution cooled to room temperature is centrifuged to obtain a precipitate, it is then washed with a mixed solution of ethanol and cyclohexane, centrifuged and dried to obtain the single rare earth doped fluoride.

5. The preparation method according to claim 4, characterized in that: In the step 4), the injection rate of solution A is 1.25 mL / min to 2 mL / min; in the step 5), the injection rate of solution B is 1.25 mL / min to 2 mL / min.

6. A flexible scintillating screen based on high-performance single rare earth doped fluoride, characterized in that: The flexible scintillator screen is mainly composed of a substrate and a luminescent scintillator loaded inside the substrate; the luminescent scintillator is a high-performance single rare earth doped fluoride as described in any one of claims 1 to 3 or a high-performance single rare earth doped fluoride obtained by the preparation method as described in any one of claims 4 to 5.

7. The flexible scintillation screen according to claim 6, characterized in that: The flexible scintillating screen is mainly formed by mixing a luminescent scintillator, an organic solvent and a prepolymer solution of a substrate in a mass ratio of 0.7 to 1.1:1:10, followed by spin coating and drying.

8. An application of the flexible scintillating screen as claimed in claim 6 or 7 in X-ray high-resolution imaging of an object, characterized in that: The imaging includes one of real-time planar imaging, real-time non-planar imaging, delayed planar imaging and delayed non-planar imaging.

9. The use according to claim 8, characterized in that: The thickness of the flexible scintillating screen is 0.9-1.2 mm, and it emits light under X-ray excitation, with a radioluminescence wavelength of 490-620 nm and a maximum spatial resolution of 16.1 lp mm -1 .

10. The use according to claim 8, characterized in that: After being irradiated by X-rays, the flexible scintillating screen is first subjected to heat treatment and then to delayed imaging; the conditions of the heat treatment are: heating for 30 to 40 minutes at an ambient temperature of 60 to 70°C.

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