Method for improving photoyield of Cs3Cu2I5 scintillator through Cr < 3 + > / Mn < 2 + > co-doping

Abstract

The invention discloses a method for improving the photoyield of a Cs3Cu2I5 scintillator through Cr < 3 + > / Mn < 2 + > co-doping. Compared with a traditional high-temperature melting method, a vacuum evaporation method, an anti-solvent method and other processes which depend on complex equipment, high temperature and high pressure or a large amount of toxic organic solvents, the method has the advantages that important innovation is achieved on the scintillator preparation process, and high efficiency, environment friendliness and excellent expandability are achieved; according to the method, a solution method cooling crystallization strategy taking a hydroiodic acid-hypophosphorous acid mixed solution as a medium is adopted, so that the process is fundamentally simplified, the reaction condition is mild, the dependence on harsh equipment and the preparation cost are remarkably reduced, meanwhile, the use of a toxic solvent is avoided, and the method has better environmental friendliness. According to the method, heating reaction is carried out at the temperature of 180-240 DEG C for only 0.5-2.0 hours, then natural cooling is carried out for 8-24 hours, a large number of evenly-crystallized Cs3Cu2I5: Cr < 3 + > and Mn < 2 + > small broken crystals can be obtained, the technological process is high in controllability and repeatability, large-scale preparation of large-area and high-quality scintillator materials is easy to achieve, and a reliable path is provided for industrial popularization.

Description

Technical Field

[0001] This invention belongs to the field of inorganic scintillator material preparation technology, and relates to a method for preparing inorganic scintillator materials using Cr 3+ / Mn 2+ A method for improving the light yield of Cs3Cu2I5 scintillator through co-doping. Background Technology

[0002] X-ray imaging technology has wide applications in medical diagnosis, defense industry, nuclear technology, and radiation safety detection. In X-ray imaging systems, the scintillator, as its core component, converts high-energy X-ray photons into low-energy photons, thereby enabling X-ray detection and imaging. Therefore, the performance of the scintillator directly determines the overall performance of the imaging system and the final image quality. An ideal scintillator material typically needs to possess the following key characteristics: high absorption coefficient for X-rays, high light yield, and high imaging spatial resolution. Among many scintillator materials, traditional inorganic scintillators have always held an important position due to their excellent physicochemical stability and scintillation performance. However, they still have significant limitations in practical applications. For example, CdWO4 has a high synthesis temperature and high brittleness, making it prone to cracking along cleavage during processing; Bi4Ge3O4... 12 (BGO) has low light yield and long decay time; YAlO3:Ce (YAP:Ce) has a small effective atomic number, resulting in limited light yield; while CsI:Tl faces problems such as severe afterglow. In recent years, copper-based metal halides with self-trapped exciton luminescence, such as Cs3Cu2I5, have shown promising application potential in X-ray detection and imaging due to their excellent X-ray absorption, large Stokes shift, and lack of self-absorption. However, the insufficient light yield of Cs3Cu2I5 scintillators remains a key bottleneck restricting their commercial application. Currently, neither pure-phase Cs3Cu2I5 nor single-metal ion doping strategies have achieved breakthroughs in energy conversion efficiency, making it difficult to meet commercial requirements. Therefore, exploring new performance optimization strategies is crucial. Co-doping, as a key technology that can optimize energy transfer paths and improve luminescence efficiency, is a potential solution to the above problems. However, to date, the use of Cr... 3+ / Mn 2+ No literature or patent reports have been found on the method of ion pair co-doping to improve the light yield of Cs3Cu2I5 scintillator. Summary of the Invention

[0003] The purpose of this invention is to provide a simple and repeatable process for Cr 3+ / Mn 2+A method for improving the light yield of Cs3Cu2I5 scintillators through co-doping. This method is carried out in solution, with simple process parameters and adjustable dopant concentration and doping temperature. Compared with undoped Cs3Cu2I5, the light yield is significantly improved, approaching that of commercial scintillators.

[0004] The technical solution of the present invention is as follows:

[0005] A method using Cr 3+ / Mn 2+ A method for improving the optical yield of Cs3Cu2I5 scintillators through co-doping, wherein Cr 3+ The doping concentration is 1%, Mn 2+ The doping concentration is 1-10%.

[0006] The above co-doping is achieved through a solution method, including the following steps:

[0007] 1) Add cesium iodide, cuprous iodide, divalent manganese compounds, and trivalent chromium compounds to a certain volume of a mixed solution of hydroiodic acid and hypophosphorous acid;

[0008] 2) Heat and stir the precursor solution from step 1) until it is completely dissolved and forms a transparent solution;

[0009] 3) Cool the transparent solution from step 2) naturally to room temperature to obtain a large number of small crystal fragments;

[0010] 4) The small crystal fragments from step 3) were washed multiple times with isopropanol and dried in a vacuum drying oven to obtain Cs3Cu2I5:Cr 3+ , Mn 2+ Scintillator.

[0011] In step 1), the divalent manganese compound is any one or more of manganese acetate, manganese carbonate, and manganese iodide, and the trivalent chromium compound is any one or more of chromium acetate, chromium carbonate, and chromium iodide.

[0012] In step 1), the volume of hydroiodic acid is 5-10 ml, and the volume of hypophosphoric acid is 0.5-1.0 ml.

[0013] In step 1), Cr 3+ The doping concentration is 1%, Mn 2+ The doping concentration is 1% to 10%.

[0014] In step 2), the heating temperature is 180 to 240 °C, and the time is 0.5 to 2.0 hours.

[0015] In step 3), the cooling time is 8-24 hours.

[0016] In step 4), the isopropanol washing is performed 3 times, the drying temperature is 25 °C, and the drying time is 1 hour.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] (1) This method represents a significant innovation in scintillator preparation, combining high efficiency, environmental friendliness, and excellent scalability. Compared to traditional high-temperature melting, vacuum evaporation, and anti-solvent methods, which rely on complex equipment, high temperatures and pressures, or large amounts of toxic organic solvents, this invention innovatively employs a solution-based cooling crystallization strategy using a hydroiodic acid-hypophosphoric acid mixed solution as the medium. This process fundamentally simplifies the procedure, provides mild reaction conditions, significantly reduces reliance on demanding equipment and preparation costs, and avoids the use of toxic solvents, thus exhibiting better environmental friendliness. Furthermore, this method requires only 0.5–2.0 hours of heating at 180–240 °C, followed by 8–24 hours of natural cooling to obtain a large quantity of uniformly crystalline Cs3Cu2I5:Cr. 3+ , Mn 2+ Small-crystal fragments offer strong process control and high repeatability, facilitating the large-scale preparation of large-area, high-quality scintillator materials and providing a reliable path for industrialization.

[0019] (2) Through Cr 3+ / Mn 2+ The co-doping strategy significantly improves light yield, demonstrating clear compositional and performance innovations. While existing Cs3Cu2I5 scintillators possess certain luminescent properties, their light yield still has room for improvement. This invention introduces 1% Cr into the crystal simultaneously... 3+ With 1%-10% Mn 2+ An effective energy transfer channel was constructed, and the synergistic effect between the two ions was utilized to enhance the capture and radiative transition efficiency of the excitation energy, thereby optimizing the light yield.

[0020] (3) The small fragmented crystal morphology of the prepared crystals is beneficial for device integration and performance. The Cr prepared in this invention... 3+ / Mn 2+ Co-doped Cs3Cu2I5 small crystal fragments are easily composited with polymers to form flexible thin films, overcoming the problem that traditional bulk crystals are difficult to adapt to flexible detection systems. This composite structure not only enhances the optical coupling efficiency between the scintillator and the detector and reduces interface light loss, but can also be directly used to prepare large-area, lightweight, and flexible X-ray imaging panels, providing a key material basis for the development of next-generation high-resolution, low-cost imaging equipment. Attached Figure Description

[0021] Figure 1The Cs3Cu2I5 synthesized under the conditions shown in Example 1 of this invention: 1%Cr 3+ 1%Mn 2+ Photograph of the sample under 254nm ultraviolet light illumination;

[0022] Figure 2 The Cs3Cu2I5 synthesized under the conditions shown in Example 1 of this invention: 1%Cr 3+ 1%Mn 2+ A photograph of the sample under X-ray irradiation;

[0023] Figure 3 The powder X-ray diffraction (XRD) patterns of the samples prepared in Examples 1, 4, and 6 of this invention and Comparative Example 1 demonstrate that doping did not change the crystal structure.

[0024] Figure 4 The emission spectra of Embodiments 1, 4, and 6 of the present invention and Comparative Examples 1, 2, and 3 under ultraviolet light excitation are shown.

[0025] Figure 5 The images show the scintillation emission spectra of Examples 1, 4, and 6 of the present invention and Comparative Examples 1, 2, and 3 under X-ray excitation. Detailed Implementation

[0026] The present invention will be further illustrated below with reference to the accompanying drawings and specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. After reading this invention, any modifications to the invention by those skilled in the art in various equivalent forms will fall within the scope defined by the appended claims.

[0027] Comparative Example 1: An undoped Cs3Cu2I5 scintillator was prepared, with all other technical features being the same as in Example 4;

[0028] Comparative Example 2: Preparation of a product doped with only 1% Cr 3+ The Cs3Cu2I5 scintillator has the same technical features as in Example 4.

[0029] Comparative Example 3: Preparation of a product doped with only 6% Mn 2+ The Cs3Cu2I5 scintillator has the same technical features as in Example 4.

[0030] Example 1

[0031] The chemical formula is Cs3Cu2I5: 1%Cr 3+ 1%Mn 2+The preparation method of the co-doped scintillator is as follows: Weigh 3.0 mmol of cesium iodide, 2.0 mmol of cuprous iodide, 0.02 mmol of chromium acetate, and 0.02 mmol of manganese acetate. All operations are carried out in an argon-filled glove box to avoid water and oxygen. Dissolve the above raw materials together in 5.0 mL of hydroiodic acid and 1.0 mL of hypophosphorous acid, and stir magnetically at 150 °C for 3.0 hours until the reactants are completely dissolved to obtain the precursor solution. Turn off the stirrer, stop heating and stirring, and let the precursor solution in the reaction flask stand overnight. Then, by cooling crystallization, well-crystallized Cs3Cu2I5:Cr is formed from the above precursor solution. 3+ , Mn 2+ Scintillator. From Figure 1 It can be seen that under ultraviolet light excitation at a wavelength of 254 nm, Cs3Cu2I5: 1%Cr 3+ 1%Mn 2+ The scintillator emits a blue light. Figure 2 The results show that under X-ray excitation (80 kV, 100 uA), Cs3Cu2I5: 1%Cr 3+ 1%Mn 2+ The scintillator exhibits a bright blue glow.

[0032] Example 2

[0033] The chemical formula is Cs3Cu2I5: 1%Cr 3+ 2%Mn 2+ The preparation method of the co-doped scintillator is as follows: Weigh 3.0 mmol of cesium iodide, 2.0 mmol of cuprous iodide, 0.02 mmol of chromium acetate, and 0.04 mmol of manganese acetate. All operations are carried out in an argon-filled glove box to avoid water and oxygen. Dissolve the above raw materials together in 5.0 mL of hydroiodic acid and 1.0 mL of hypophosphorous acid, and stir magnetically at 150 °C for 3.0 hours until the reactants are completely dissolved to obtain the precursor solution. Turn off the stirrer, stop heating and stirring, and let the precursor solution in the reaction flask stand overnight. Then, by cooling crystallization, well-crystallized Cs3Cu2I5:Cr is formed from the above precursor solution. 3+ , Mn 2+ Scintillator.

[0034] Example 3

[0035] The chemical formula is Cs3Cu2I5: 1%Cr 3+ 4%Mn 2+The preparation method of the co-doped scintillator is as follows: Weigh 3.0 mmol of cesium iodide, 2.0 mmol of cuprous iodide, 0.02 mmol of chromium acetate, and 0.08 mmol of manganese acetate. All operations are carried out in an argon-filled glove box to avoid water and oxygen. Dissolve the above raw materials together in 5.0 mL of hydroiodic acid and 1.0 mL of hypophosphorous acid, and stir magnetically at 150 °C for 3.0 hours until the reactants are completely dissolved to obtain the precursor solution. Turn off the stirrer, stop heating and stirring, and let the precursor solution in the reaction flask stand overnight. Then, by cooling crystallization, well-crystallized Cs3Cu2I5:Cr is formed from the above precursor solution. 3+ , Mn 2+ Scintillator.

[0036] Example 4

[0037] The chemical formula is Cs3Cu2I5: 1%Cr 3+ 6%Mn 2+ The preparation method of the co-doped scintillator is as follows: Weigh 3.0 mmol of cesium iodide, 2.0 mmol of cuprous iodide, 0.02 mmol of chromium acetate, and 0.12 mmol of manganese acetate. All operations are carried out in an argon-filled glove box to avoid water and oxygen. Dissolve the above raw materials together in 5.0 mL of hydroiodic acid and 1.0 mL of hypophosphorous acid, and stir magnetically at 150 °C for 3.0 hours until the reactants are completely dissolved to obtain the precursor solution. Turn off the stirrer, stop heating and stirring, and let the reaction flask stand overnight until well-crystallized Cs3Cu2I5:Cr 3+ , Mn 2+ Scintillator.

[0038] Example 5

[0039] The chemical formula is Cs3Cu2I5: 1%Cr 3+ 8%Mn 2+ The preparation method of the co-doped scintillator is as follows: Weigh 3.0 mmol of cesium iodide, 2.0 mmol of cuprous iodide, 0.02 mmol of chromium acetate, and 0.16 mmol of manganese acetate. All operations are carried out in an argon-filled glove box to avoid water and oxygen. Dissolve the above raw materials together in 5.0 mL of hydroiodic acid and 1.0 mL of hypophosphorous acid, and stir magnetically at 150 °C for 3.0 hours until the reactants are completely dissolved to obtain the precursor solution. Turn off the stirrer, stop heating and stirring, and let the precursor solution in the reaction flask stand overnight. Then, by cooling crystallization, well-crystallized Cs3Cu2I5:Cr is formed from the above precursor solution. 3+ , Mn 2+ Scintillator.

[0040] Example 6

[0041] The chemical formula is Cs3Cu2I5: 1%Cr 3+ 10%Mn 2+ The preparation method of the co-doped scintillator is as follows: Weigh 3.0 mmol of cesium iodide, 2.0 mmol of cuprous iodide, 0.02 mmol of chromium acetate, and 0.20 mmol of manganese acetate. All operations are carried out in an argon-filled glove box to avoid water and oxygen. Dissolve the above raw materials together in 5.0 mL of hydroiodic acid and 1.0 mL of hypophosphorous acid, and stir magnetically at 150 °C for 3.0 hours until the reactants are completely dissolved to obtain the precursor solution. Turn off the stirrer, stop heating and stirring, and let the precursor solution in the reaction flask stand overnight. Then, by cooling crystallization, well-crystallized Cs3Cu2I5:Cr is formed from the above precursor solution. 3+ , Mn 2+ Scintillator.

[0042] Figure 3 The powder X-ray diffraction (XRD) patterns of samples 1, 4, and 6 in this example and Comparative Example 1 are shown below. Figure 3 It can be seen that the crystal structure of these three samples has not changed compared to pure Cs3Cu2I5, indicating that Cr 3+ , Mn 2+ The doping did not introduce new impurity phases.

[0043] Figure 4 The images show the fluorescence emission spectra of samples 1, 4, and 6 in Examples 1, 2, and 3, and those in Comparative Examples 1, 2, and 3, under 254 nm UV excitation. Figure 4 It can be seen that the fluorescence spectra of Examples 4 and 6 and Comparative Example 3 all contain two emission centers, located at ~455 nm and ~565 nm, respectively. The ~455 nm emission peak is attributed to the intrinsic emission of the Cs3Cu2I5 matrix, while the ~565 nm emission peak is attributed to Mn. 2+ dd transition ( 4 T1 - 6 A1). With Mn 2+ Increasing the ion doping concentration significantly enhances the emission intensity at 565 nm; the intensity reaches its maximum when the doping concentration reaches 6% (Example 4), and then decreases due to concentration quenching. It is noteworthy that at the same Mn... 2+ At a doping concentration of 6%, 1% Cr 3+ , with 6% Mn 2+ The fluorescence intensity of the co-doped sample (Example 4) was significantly better than that of the single-doped 6% Mn. 2+The sample (Comparative Example 3) shows that Cr 3+ The introduction of Mn 2+ The luminescence of the light has a significant synergistic enhancement effect.

[0044] Figure 5 The images show the radiative emission spectra of Examples 1, 4, and 6 and Comparative Examples 1, 2, and 3 under X-ray excitation. A comparison shows that the spectral variation trend under X-ray excitation is basically consistent with that under ultraviolet excitation: as Mn... 2+ With increasing ion doping concentration, the emission peak intensity at 565 nm is significantly enhanced. 2+ When the doping concentration reaches 6% (Example 4), the radiative luminescence intensity reaches its maximum value. Simultaneously, 1% Cr... 3+ With 6% Mn 2+ The co-doped sample (Example 4) also exhibited the best radiative emission performance, further verifying the Cr... 3+ For Mn 2+ The luminescence plays a promoting role.

[0045] The above embodiments are merely illustrative of several specific implementations of the present invention and should not be construed as limiting the scope of the present invention. Any modifications, substitutions, and improvements made by those skilled in the art without departing from the design and concept of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method using Cr 3+ / Mn 2+ A method for improving the optical yield of Cs3Cu2I5 scintillators through co-doping, characterized in that, Using Cr 3+ Ions and Mn 2+ Ions are used to co-dope the Cs3Cu2I5 scintillator.

2. The method according to claim 1, characterized in that, The co-doping is achieved through a solution method, including the following steps: 1) Add cesium iodide, cuprous iodide, divalent manganese compounds, and trivalent chromium compounds to a certain volume of a mixed solution of hydroiodic acid and hypophosphorous acid; 2) Heat and stir the precursor solution from step 1) until it is completely dissolved and forms a transparent solution; 3) Cool the transparent solution from step 2) naturally to room temperature to obtain a large number of small crystal fragments; 4) The small crystal fragments from step 3) were washed multiple times with isopropanol and dried in a vacuum drying oven to obtain Cs3Cu2I5:Cr 3 + , Mn 2+ Scintillator.

3. The method according to claim 2, characterized in that, In step 1), the divalent manganese compound is any one or more of manganese acetate, manganese carbonate, and manganese iodide, and the trivalent chromium compound is any one or more of chromium acetate, chromium carbonate, and chromium iodide.

4. The method according to claim 2 or 3, characterized in that, In step 1), the volume of hydroiodic acid is 5-10 ml, and the volume of hypophosphoric acid is 0.5-1.0 ml.

5. The method according to claim 4, characterized in that, The Cr 3+ The doping concentration is 1%, Mn 2+ The doping concentration is 1% to 10%.

6. The method according to claim 5, characterized in that, In step 2), the heating temperature is 180 to 240°C, and the time is 0.5 to 2.0 hours.

7. The method according to claim 2, 3, 5, or 6, characterized in that, In step 3), the cooling time is 8-24 hours.

8. The method according to claim 7, characterized in that, In step 4), the isopropanol washing is performed 3 times, the drying temperature is 25 °C, and the drying time is 1 hour.

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