Rare earth based halide scintillator and preparation method and application thereof

Abstract

The invention discloses a rare earth based halide scintillator and a preparation method and application thereof, and belongs to the technical field of functional materials. The chemical formula of the rare earth based halide scintillator provided by the invention is RE (DMSO) 8 [Bi < 1-x > Sb < x > Cl6], wherein 0 < x < = 1; rE is a rare earth element; dMSO is a dimethyl sulfoxide ligand. By introducing the DMSO ligand and combining antimony doping, the formed rare earth based halide scintillator has intrinsic high atomic number, no self-absorption rare earth emission, no toxic element and outstanding comprehensive optical performance, so that the antimony-doped rare earth based halide scintillator has good luminescence performance and can be applied to the field of luminescent devices. Particularly, the compound has good fluorescence quantum efficiency and light yield, and has a good application prospect in the fields of detection, imaging or luminescence.

Description

Technical Field

[0001] The present invention belongs to the technical field of functional materials, and in particular relates to a rare earth-based halide scintillator and a preparation method and application thereof. Background Art

[0002] Scintillators are luminescent materials that convert high-energy photons, such as X-rays, into ultraviolet or visible light. Combined with conventional photodetectors, they enable the detection, discrimination, and quantitative analysis of various high-energy radiation. Scintillators are widely used in nondestructive safety detection, nuclear medicine imaging diagnostics, high-energy nuclear physics, environmental exploration, and astronomical exploration.

[0003] Traditional X-ray scintillators, such as Bi4Ge3O 12 、Lu3Al5O 12 :Ce and CsI:Tl single crystals are favored due to their high light yield. However, their crystal growth requires high temperature conditions, which hinders their widespread application. Recently, rare earth halide scintillators have been found to have significant advantages as an alternative, such as simpler manufacturing processes and superior X-ray response, making them a strong competitor to traditional materials. However, due to the shortcomings of rare earths such as small absorption cross-sections, limited excitation wavelengths, and strong matrix dependence, their direct application in radiation detection is limited. Summary of the Invention

[0004] In order to overcome at least one of the problems existing in the above-mentioned prior art, one of the objectives of the present invention is to provide a rare earth-based halide scintillator having good fluorescence quantum efficiency and light yield.

[0005] A second object of the present invention is to provide a method for preparing the above-mentioned rare earth-based halide scintillator.

[0006] A third object of the present invention is to provide an application of the above-mentioned rare earth-based halide scintillator.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is:

[0008] The first aspect of the present invention provides a rare earth halide scintillator, wherein the chemical formula of the rare earth halide scintillator is RE(DMSO)8[Bi 1-x Sb x Cl6]; wherein, 0<x≤1; RE is a rare earth element; DMSO is a dimethyl sulfoxide ligand.

[0009] In some embodiments of the present invention, in the rare earth halide scintillator, RE forms an octahedral structure with DMSO, and Bi and Sb form a hexacoordinate structure with Cl respectively; specifically, Bi and Cl form a [BiCl6] octahedral unit, and Sb and Cl form a [SbCl6] octahedral unit.

[0010] Preferably, RE is terbium (Tb) or europium (Eu); more preferably, RE is terbium (Tb).

[0011] The rare earth-based halide scintillator of the present invention can be prepared by using Tb or Eu as the rare earth element, which can achieve higher luminescence performance. In particular, the use of Tb can achieve higher fluorescence quantum efficiency and light yield.

[0012] Preferably, the value of x can be any value among 0.01, 0.05, 0.1, 0.2, 0.3, 0.5, 0.7 or 1, or a range between any two values.

[0013] By adjusting the value of x, that is, adjusting the doping concentration of antimony (Sb), better luminescence performance, especially higher fluorescence quantum efficiency and light yield, can be obtained.

[0014] Preferably, when RE is terbium, 0.01≤x≤0.1; for example, the value of x can be any value among 0.01, 0.03, 0.05, 0.07 or 0.1, or a range between any two values.

[0015] Preferably, when RE is europium, 0.1≤x≤0.3; for example, the value of x can be any value among 0.1, 0.15, 0.2, 0.25 or 0.3, or a range between any two values.

[0016] For different rare earth elements (RE), by optimizing the value of x, that is, optimizing the doping concentration of antimony (Sb), better luminescence performance, especially higher fluorescence quantum efficiency and light yield, can be obtained.

[0017] The second aspect of the present invention provides a method for preparing the rare earth-based halide scintillator described in the first aspect of the present invention, comprising the following steps: according to the chemical formula of the rare earth-based halide scintillator, compounds containing corresponding components are taken as raw materials according to the stoichiometric ratio of the stoichiometric ratio, the raw materials are mixed, sealed and heated, cooled, and crystallized to obtain the rare earth-based halide scintillator.

[0018] Preferably, the heating insulation temperature is 70-100°C; more preferably 70-90°C; for example, it can be any value among 70°C, 75°C, 80°C, 85°C or 90°C or a range between any two values.

[0019] Preferably, the heating holding time is 1 to 5 minutes; for example, it can be any value among 1 minute, 2 minutes, 3 minutes, 4 minutes or 5 minutes, or a range between any two of them.

[0020] Preferably, the cooling rate is 1-5°C / h; for example, it can be any value among 1°C / h, 2°C / h, 3°C / h, 4°C / h or 5°C / h, or a range between any two values.

[0021] Preferably, the end temperature of the cooling is 20-30° C., for example, any one of 20° C., 22° C., 25° C., 27° C. or 30° C., or a range of any two thereof. Specifically, the end temperature of the cooling is room temperature.

[0022] Preferably, the raw material containing the RE element comprises at least one of rare earth chloride, rare earth oxide, rare earth acetate, rare earth nitrate, or rare earth sulfate. Further preferably, the raw material containing the RE element comprises rare earth chloride, rare earth oxide, or a combination thereof. Even more preferably, the raw material containing the RE element is selected from rare earth chlorides. For example, when the RE is terbium (Tb), the rare earth chloride may be terbium chloride (TbCl3); and when the RE is europium (Eu), the rare earth chloride may be europium chloride (EuCl3).

[0023] Preferably, the raw material containing Bi element includes at least one of bismuth chloride, bismuth oxide, bismuth acetate, bismuth nitrate or bismuth sulfate; further preferably, the raw material containing Bi element includes bismuth chloride, bismuth oxide or a combination thereof; further preferably, the raw material containing Bi element is selected from bismuth oxide (Bi2O3).

[0024] Preferably, the raw material containing the Sb element includes at least one of antimony chloride, antimony oxide, antimony acetate, antimony nitrate or antimony sulfate; further preferably, the raw material containing the Sb element includes antimony chloride, antimony oxide or a combination thereof; further preferably, further preferably, the raw material containing the Sb element is selected from antimony chloride (SbCl3).

[0025] Preferably, the raw material containing the Cl element includes at least one of hydrochloric acid, rare earth chloride, bismuth chloride or antimony chloride; further preferably, the raw material containing the Cl element includes hydrochloric acid (HCl), rare earth chloride (such as TbCl3, EuCl3) and antimony chloride (SbCl3).

[0026] Preferably, the raw material containing a DMSO ligand includes dimethyl sulfoxide; further preferably, the raw material containing a DMSO ligand is selected from dimethyl sulfoxide (DMSO).

[0027] Preferably, the raw material containing RE element is selected from rare earth chlorides (such as TbCl3, EuCl3); the raw material containing Bi element is selected from bismuth oxide (Bi2O3); the raw material containing Sb element is selected from antimony chloride (SbCl3); the raw material containing Cl element includes hydrochloric acid (HCl), rare earth chlorides (such as TbCl3, EuCl3) and antimony chloride (SbCl3); the raw material containing DMSO ligand is selected from dimethyl sulfoxide (DMSO).

[0028] Preferably, the molar ratio of the rare earth chloride, bismuth oxide and antimony chloride is 1:(0.5-0.5x):x; the usage ratio of the rare earth chloride to dimethyl sulfoxide is 1 mmol:(1.5-2) mL; the usage ratio of the bismuth oxide to hydrochloric acid is (0.5-0.5x) mmol:(0.7-0.7x) mL; 0<x≤1.

[0029] By controlling the types and dosage ratios of the raw materials, a better reaction between the raw materials can be achieved. When x is 1, it means that the rare earth halide scintillator does not contain Bi, the raw materials do not include bismuth oxide, and hydrochloric acid may not be added.

[0030] Preferably, the hydrochloric acid is concentrated hydrochloric acid.

[0031] The third aspect of the present invention provides an application of the rare earth-based halide scintillator described in the first aspect of the present invention, or the rare earth-based halide scintillator prepared by the preparation method described in the second aspect of the present invention in the fields of detection, imaging or luminescence.

[0032] Specifically, the application of the rare earth-based halide scintillator in the detection field includes being used as safe and non-destructive detection materials, nuclear physics detection materials, environmental exploration materials, astronomical detection materials, etc.; the application of the rare earth-based halide scintillator in the imaging field includes being used as nuclear medicine imaging materials, X-ray imaging materials, etc.; the application of the rare earth-based halide scintillator in the luminescence field includes being used as down-conversion lighting phosphor materials, up-conversion luminescent biological imaging materials, laser materials, etc.

[0033] The beneficial effects of the present invention are as follows: the rare earth halide scintillator formed by introducing a DMSO ligand and combining it with antimony doping has an intrinsically high atomic number, rare earth emission without self-absorption, no toxic elements, and outstanding comprehensive optical properties, so that the antimony-doped rare earth halide scintillator has good luminescence properties, especially good fluorescence quantum efficiency and light yield, and has good application prospects in the fields of detection, imaging or luminescence.

[0034] Specifically, compared with the prior art, the present invention has the following advantages:

[0035] (1) The rare earth halide scintillator synthesis method of the present invention is a solvent thermal crystallization method, which has a simple and efficient preparation process, a low heating temperature, a high yield of the formed product, stable performance, and a high performance reproducibility, which is conducive to large-scale production.

[0036] (2) By doping with bismuth and antimony ions, the present invention effectively overcomes the shortcomings of rare earth elements, such as their small absorption cross-section, limited excitation wavelength, and strong matrix dependence, thereby developing high-performance rare earth-based halide scintillators. By regulating the antimony ion doping concentration, good fluorescence quantum efficiency and light yield can be achieved. The resulting antimony-doped rare earth-based halide scintillator is environmentally friendly, low-cost, and has outstanding overall performance.

[0037] (3) The light yield of the rare earth halide scintillator prepared by the present invention can reach over 19000 photons / MeV under X-ray irradiation, which is much higher than that of commercial Bi4Ge3O 12 Crystal (8000photons / MeV); fluorescence quantum efficiency can be as high as over 79%; imaging and detection performance are good, and the minimum detection limit can be as low as 124nGy / s, meeting the requirement of less than 5.5Gy / s in medical applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 The X-ray powder diffraction patterns of the crystal samples of Example 1 and Example 2 are shown.

[0039] Figure 2 This is the single crystal structure analysis diagram of the crystal sample of Example 1.

[0040] Figure 3 These are the excitation and emission spectra of the crystal samples of Example 1 and Example 2.

[0041] Figure 4 This is a fluorescence quantum efficiency test diagram of the crystal samples of Example 1 and Example 2.

[0042] Figure 5 2 are fluorescence lifetime diagrams of the crystal samples of Example 1 and Example 2.

[0043] Figure 6 These are the radiation emission spectra of the crystal samples of Example 1 and Example 2 under X-ray irradiation.

[0044] Figure 7 This is the X-ray imaging image of the crystal sample in Example 1.

[0045] Figure 8 This is a characterization diagram of the X-ray response performance of the crystal sample in Example 1. DETAILED DESCRIPTION

[0046] The content of the present invention is further described in detail below through specific examples. It should be understood that the following examples are only used to further illustrate the present invention and cannot be interpreted as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the principles set forth in the present invention all fall within the scope of protection of the present invention. The specific process parameters and the like in the following examples are only examples within a suitable range, and those skilled in the art can make selections within a suitable range through the description herein, and are not limited to the specific data exemplified below. The raw materials, reagents or devices used in the following examples and comparative examples, unless otherwise specified, can be obtained from conventional commercial sources, or can be obtained by existing known methods.

[0047] Example 1

[0048] An antimony-doped terbium-based halide scintillator, the chemical formula of which is Tb(DMSO)8[Bi 0.95 Sb 0.05 Cl6], the preparation method is as follows:

[0049] Weigh 1mmol TbCl3, 0.475mmol Bi2O3 and 0.05mmol SbCl3, and measure 2mL DMSO and 0.665mL HCl. Mix the weighed powder and the measured solution in a 20mL sealed glass vial. Then heat the mixed solution in the vial and stir it magnetically. Heat and stir at 70℃ for 2min to form a transparent clear solution. Place the obtained clear solution in a temperature-controlled oven and set the program to slowly cool to room temperature at 5℃ / h to obtain the required Tb(DMSO)8[Bi 0.95 Sb 0.05 Cl6] crystals and residual solution, the reaction solution and crystals were filtered and dried in turn to obtain Tb(DMSO)8[Bi 0.95 Sb 0.05 Cl6] crystal samples.

[0050] The powder X-ray diffraction (PXRD) pattern of the crystal sample of Example 1 is as follows: Figure 1 As shown, the single crystal structure analysis diagram is as follows Figure 2 As shown. Figures 1-2 It can be seen that the structure of the crystal sample of Example 1 is that 8 oxygen atoms in DMSO form octa-coordination with 1 rare earth terbium atom, and [BiCl6] and [SbCl6] octahedral units exist at the same time.

[0051] The excitation and emission spectra of the crystal sample of Example 1 are as follows Figure 3 As shown in the fluorescence quantum efficiency test diagram Figure 4 As shown in the fluorescence lifetime diagram of terbium emission, Figure 5 As shown. Figures 3-5It can be seen that the emission band of the crystal sample of Example 1 is located at 450-850nm, with a characteristic Tb of 545nm 3+ Emission and Sb 3+ The broadband self-trapped exciton emission of Tb-doped 3+ The characteristic emission lifetime is 1.87ms.

[0052] The radiation emission spectrum of the crystal sample of Example 1 under X-ray irradiation is shown in FIG. Figure 6 As shown, X-ray imaging Figure 7 As shown, the X-ray response performance characterization diagram is as follows Figure 8 As shown. Figures 6-8 It can be seen that under X-ray excitation, the light yield of the crystal sample in Example 1 is 19022 photons / MeV; when used for X-ray imaging, the internal structural features of the chip can be clearly observed; the minimum detection limit of this scintillator is 124 nGy / s, which meets the requirement of less than 5.5 μGy / s for medical applications.

[0053] Example 2

[0054] An antimony-doped europium-based halide scintillator with the chemical formula Eu(DMSO)8[Bi 08 Sb 0.2 Cl6], the preparation method is as follows:

[0055] Weigh 1mmol EuCl3, 0.4mmol Bi2O3 and 0.2mmol SbCl3, and measure 1.5mL DMSO and 0.56mL HCl. Mix the weighed powder and the measured solution in a 20mL sealed glass vial. Then heat the mixed solution in the vial and stir it magnetically. Heat and stir at 90℃ for 2min to form a transparent clear solution. Place the obtained clear solution in a temperature-controlled oven and set the program to slowly cool to room temperature at 1℃ / h to obtain the required Eu(DMSO)8[Bi 08 Sb 0.2 Cl6] crystals and residual solution, the obtained reaction solution and crystals were filtered and dried in turn to obtain Eu(DMSO)8[Bi 08 Sb 0.2 Cl6] crystal samples.

[0056] The powder X-ray diffraction pattern of the crystal sample of Example 2 is as follows: Figure 1 The excitation and emission spectra are shown in Figure 3 As shown, the fluorescence quantum efficiency test is as follows Figure 4 As shown in the fluorescence lifetime diagram of europium emission, Figure 5 As shown, the radiation emission spectrum under X-ray irradiation is as follows Figure 6As shown in the figure, the emission band of the crystal sample of Example 2 is located at 450-850nm, with a characteristic Eu of 612nm 3+ Emission and Sb 3+ The broadband self-trapped exciton emission of Eu 3+ The characteristic emission lifetime is 1.35ms; under X-ray excitation, the light yield is 8497photons / MeV.

[0057] The rare earth halide scintillator synthesis method in the embodiment of the present invention is a solvent thermal crystallization method, which has a simple and efficient preparation process, a low heating temperature, a high yield of the formed product, stable performance, and a high performance reproducibility, and is conducive to large-scale production.

[0058] In the embodiments of the present invention, by doping with bismuth and antimony ions, the shortcomings of rare earth elements, such as their small absorption cross-section, limited excitation wavelength, and strong matrix dependence, can be effectively overcome, thereby developing a high-performance rare earth-based halide scintillator. By adjusting the antimony ion doping concentration, excellent fluorescence quantum efficiency and light yield can be achieved. The resulting antimony-doped rare earth-based halide scintillator is environmentally friendly, low-cost, and has outstanding overall performance.

[0059] The rare earth halide scintillator prepared in the embodiment of the present invention can produce a light yield of up to 19000 photons / MeV under X-ray irradiation, which is much higher than that of commercial Bi4Ge3O 12 Crystal (8000photons / MeV); fluorescence quantum efficiency can be as high as over 79%; imaging and detection performance are good, and the minimum detection limit can be as low as 124nGy / s, meeting the requirement of less than 5.5Gy / s in medical applications.

[0060] In summary, the rare earth halide scintillator formed by the present invention by introducing DMSO ligands and combining antimony doping has an intrinsically high atomic number, rare earth emission without self-absorption, no toxic elements, and outstanding comprehensive optical properties. This makes the antimony-doped rare earth halide scintillator have good luminescence properties, especially good fluorescence quantum efficiency and light yield, and has good application prospects in the fields of detection, imaging or luminescence.

Claims

1. A rare earth halide scintillator, characterized in that: The chemical formula of the rare earth halide scintillator is RE(DMSO)8[Bi 1-x Sb x Cl6]; wherein, 0<x≤1; RE is a rare earth element; DMSO is a dimethyl sulfoxide ligand.

2. The rare earth halide scintillator according to claim 1, characterized in that: RE is terbium or europium.

3. The rare earth halide scintillator according to claim 1, characterized in that: When RE is terbium, 0.01≤x≤0.1; And / or, when RE is europium, 0.1≤x≤0.

3.

4. A method for preparing a rare earth-based halide scintillator according to any one of claims 1 to 3, characterized in that: The following steps are involved: According to the chemical formula of the rare earth-based halide scintillator, compounds containing corresponding components are taken as raw materials according to the stoichiometric ratio. The raw materials are mixed, sealed and heated, cooled, and crystallized to obtain the rare earth-based halide scintillator.

5. The preparation method according to claim 4, characterized in that The heating holding temperature is 70-100° C.; And / or, the heating holding time is 1 to 5 minutes.

6. The preparation method according to claim 4, characterized in that The cooling rate is 1-5°C / h; And / or, the terminal temperature of the cooling is 20-30°C.

7. The preparation method according to claim 4, characterized in that The raw material containing RE element includes at least one of rare earth chloride, rare earth oxide, rare earth acetate, rare earth nitrate or rare earth sulfate; and / or the raw material containing the Bi element includes at least one of bismuth chloride, bismuth oxide, bismuth acetate, bismuth nitrate, or bismuth sulfate; and / or the raw material containing the Sb element includes at least one of antimony chloride, antimony oxide, antimony acetate, antimony nitrate, or antimony sulfate; And / or, the raw material containing Cl element includes at least one of hydrochloric acid, rare earth chloride, bismuth chloride or antimony chloride; And / or, the starting material containing a DMSO ligand includes dimethyl sulfoxide.

8. The preparation method according to claim 7, characterized in that The raw material containing RE element is selected from rare earth chloride; the raw material containing Bi element is selected from bismuth oxide; the raw material containing Sb element is selected from antimony chloride; the raw material containing Cl element includes hydrochloric acid, rare earth chloride and antimony chloride; the raw material containing DMSO ligand is selected from dimethyl sulfoxide.

9. The preparation method according to claim 8, characterized in that The molar ratio of the rare earth chloride, bismuth oxide and antimony chloride is 1:(0.5-0.5x):x; the usage ratio of the rare earth chloride to dimethyl sulfoxide is 1 mmol:(1.5-2) mL; the usage ratio of the bismuth oxide to hydrochloric acid is (0.5-0.5x) mmol:(0.7-0.7x) mL; 0<x≤1.

10. Use of the rare earth-based halide scintillator according to any one of claims 1 to 3, or the rare earth-based halide scintillator prepared by the preparation method according to any one of claims 4 to 9 in the fields of detection, imaging or luminescence.

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