A method for preparing a perovskite scintillator powder

Abstract

The application provides a preparation method of a perovskite scintillator powder, and the specific steps are as follows: (1) preparation of an A precursor solution: a required molar amount of an A precursor halide salt is weighed, and a certain amount of deionized water or an alcohol substance is added as a solvent to make it reach a saturated or near-saturated state; (2) preparation of a B precursor solution: a required molar amount of a B precursor halide salt is weighed, and a corresponding HX or NaX solution is added as a solvent to make it reach a saturated or near-saturated state; X is one of Cl elements, Br elements or I elements; the required molar amount of the B precursor halide salt and the required molar amount of the A precursor halide salt in step (1) are the molar ratio of complete reaction of the A precursor halide salt and the B precursor halide salt; (3) after the A precursor solution and the B precursor solution are mixed and reacted at normal temperature and pressure, a corresponding perovskite microcrystal PMC precipitate can be obtained. The application has the advantages of simple and convenient preparation method and large-scale production.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of preparation of perovskite scintillators, and particularly relates to a preparation method and application of a perovskite scintillator. BACKGROUND

[0002] A scintillator is a material capable of converting high-energy radiation (X-rays, gamma rays, beta rays, etc.) or high-energy particles (alpha particles or neutrons, etc.) into low-energy ultraviolet light or visible light. Since the scintillator was discovered, it has been widely used in medical imaging, industrial exploration, high-energy physics and many other fields. The scintillator material needs a high X-ray cutoff rate to absorb and convert enough X-rays, so it is generally composed of heavy elements with a large atomic number and has a high density. In addition, the scintillator material also needs a high X-ray radiation photon yield, a fast response speed and a short afterglow time. Currently, the traditional commercial conventional scintillator is generally thallium-doped cesium iodide (CsI:Tl) material, which has problems such as high preparation temperature, great difficulty, high cost, etc., and its performance has reached the limit, which is limited by low efficiency or afterglow effect, and it is difficult to tune across the visible spectrum.

[0003] In order to solve the problems of low X-ray irradiation light yield of the current commercial scintillator and the limitation of thallium element toxicity on practical application, PMC (perovskite microcrystal) material has been widely studied in the academic field in recent years due to its advantages of high light yield, high quantum efficiency, adjustable light emission wavelength, etc. There are many types of halide PMC chemical formulas, such as ABX2, AB2X3, A2BX3, A3B2X5, wherein A is potassium (K) element, rubidium (Rb) element or cesium (Cs) element, B is copper (Cu) element or other transition metals and main group metals, including but not limited to Cu, Pb, Hg and other heavy elements, and X is chlorine (Cl), bromine (Br) or iodine (I) element. The PMC has a high cutoff rate for X-ray irradiation, and has advantages of fast response speed (nearly thousand times faster than CsI:Tl), short afterglow time (one tenth of CsI:Tl), etc., and the minimum X-ray irradiation dose that can be responded is nearly one hundredth of that of CsI:Tl. According to the previous literature, the synthesized perovskite bulk crystal is ground and ball milled to obtain PMC, and the single powder particle size can reach 2 microns, which can be well dispersed in colloidal substances and can form various specified size scintillator films, or in the form of tablets to form a scintillator with high density and certain thickness. Therefore, the PMC material is considered to have the potential to become the next generation of large-scale commercial scintillator material, which can be used to prepare an X-ray detector with ultrafast, low radiation dose and high spatial resolution.

[0004] However, the commercialization and long-term use of PMC still faces the biggest challenge: 1. Time-consuming preparation. Common laboratory processes such as slow cooling of saturated solution, solid-state reaction, solvent evaporation crystallization, etc. have a long preparation period. After obtaining the required single crystal or polycrystalline ingot, grinding or ball milling is required to obtain PMC for the preparation of scintillator thin films, which is not suitable for commercial synthesis path. 2. Waste of solvent. For example, anti-solvent recrystallization method requires the addition of four times the volume of the original solvent, which consumes a lot of solvent in the reaction and is difficult to handle a large amount of waste liquid. 3. Not suitable for large-scale reaction. For example, laboratory hot injection method is limited by the size of the reaction container and the high temperature required for preparation, which is not easy to implement in large-scale synthesis reactions.

[0005] Although PMC materials have not yet been successfully commercialized, there have been some research and development achievements in the academic community: Common PMC preparation methods such as slow cooling of saturated solution to prepare single crystals (reference Organic Electronics 86 (2020) 105903) have excellent performance, but the reaction process requires heating and maintaining a high temperature for a certain period of time to evaporate the solvent. After a long period of heating, slow cooling is still required to precipitate single crystals, which takes a long time to synthesize. In the subsequent preparation of scintillator thin films, the prepared single crystals need to be ground to obtain PMC, and the process flow is long.

[0006] Currently, the best solution in the academic community for PMC materials in terms of performance and ease of synthesis is the anti-solvent recrystallization method (reference Chem. Mater. 2020, 32, 5515-5524). By adding a certain molar ratio of CsX and CuX to dimethyl sulfoxide (DMSO) and stirring thoroughly, a precursor solution is formed. Then, by adding an anti-solvent, toluene, to the obtained precursor solution, the cesium-copper halide complex formed in DMSO can be precipitated. The powder obtained by this method is characterized by dispersing it in isopropanol, and the fluorescence quantum yield (PLQY) of Cs3Cu2Cl5 can reach nearly 100%. Even though the performance has made breakthrough progress, the introduction of toxic solvent toluene in the reaction is not suitable for large-scale preparation of Cs3Cu2Cl5. Even if alternative non-toxic anti-solvents are used to precipitate PMC, the several times the volume of the original liquid waste generated in large-scale synthesis reactions still needs to be improved.

[0007] From the above two typical PMC material preparation methods, it is not difficult to see that each has its advantages and disadvantages, and there is a certain trade-off in terms of ease of synthesis and feasibility of large-scale synthesis reactions.

[0008] As described above, the disadvantages of the prior art are as follows: 1. The synthesis reaction is slow by using saturated solution slow cooling method, solid state reaction method, solvent evaporation crystallization method, etc., and a certain post-treatment is needed to obtain the target PMC, which consumes a long time. 2. A large amount of anti-solvent is needed in the reaction of preparing PMC by using the anti-solvent method, and more waste liquid needs to be treated, which is not suitable for large-scale commercialization. 3. The reaction synthesis is limited by the size of the reaction container or needs to be carried out at high temperature by using the hot injection method, which is not suitable for large-scale preparation of PMC. SUMMARY

[0009] The purpose of the present application is to solve the above technical problems by providing a preparation method and application of a perovskite scintillator.

[0010] To achieve the above purpose, the present application adopts the following technical scheme: a preparation method of a perovskite scintillator powder, the specific steps are as follows:

[0011] (1) Preparation of A precursor solution: weigh the required molar amount of A precursor halide salt, add a certain amount of deionized water or alcohol as a solvent to make it reach a saturated or near-saturated state;

[0012] (2) Preparation of B precursor solution: weigh the required molar amount of B precursor halide salt, add the corresponding solvent HX or NaX solution to make it reach a saturated or near-saturated state; X is one of Cl element, Br element or I element; the required molar amount of the above B precursor halide salt and the required molar amount of the A precursor halide salt in step (1) are the molar ratio of the complete reaction of the A precursor halide salt and the B precursor halide salt;

[0013] (3) After mixing and reacting the A precursor solution and the B precursor solution at normal temperature and pressure, the corresponding perovskite microcrystal PMC precipitate is obtained;

[0014] (4) The perovskite microcrystal PMC precipitate obtained in step 3 is continuously washed and centrifuged using alcohol or ester;

[0015] (5) Dry the perovskite microcrystal PMC precipitate obtained in step 4 to obtain a perovskite scintillator powder.

[0016] As a preferred, the metal element in the A precursor halide salt in step (1) is one of Cs element, Rb element or K element.

[0017] As a preferred, the metal element in the B precursor halide salt in step (2) is one of Cu element, Pb element, Mn element, Ag element or Zr element.

[0018] As preferred, the near-saturation state of the A, B precursor solution in step (1) and step (2) means that the mass of the solute in the A, B precursor solution under the same conditions is greater than or equal to 50% of the mass of the A, B precursor solute in a saturated solution.

[0019] As preferred, the near-saturation state of the A, B precursor solution in step (1) and step (2) means that the mass of the solute in the A, B precursor solution under the same conditions is greater than or equal to 50% of the mass of the A, B precursor solute in a saturated solution.

[0020] As preferred, the near-saturation state of the A, B precursor solution in step (1) and step (2) means that the mass of the solute in the A, B precursor solution under the same conditions is greater than or equal to 50% of the mass of the A, B precursor solute in a saturated solution.

[0021] As preferred, the near-saturation state of the A, B precursor solution in step (1) and step (2) means that the mass of the solute in the A, B precursor solution under the same conditions is greater than or equal to 50% of the mass of the A, B precursor solute in a saturated solution.

[0022] As preferred, the near-saturation state of the A, B precursor solution in step (1) and step (2) means that the mass of the solute in the A, B precursor solution under the same conditions is greater than or equal to 50% of the mass of the A, B precursor solute in a saturated solution.

[0023] As preferred, the near-saturation state of the A, B precursor solution in step (1) and step (2) means that the mass of the solute in the A, B precursor solution under the same conditions is greater than or equal to 50% of the mass of the A, B precursor solute in a saturated solution.

[0024] As preferred, the near-saturation state of the A, B precursor solution in step (1) and step (2) means that the mass of the solute in the A, B precursor solution under the same conditions is greater than or equal to 50% of the mass of the A, B precursor solute in a saturated solution.

[0025] Compared with the prior art, the present application has the following advantages:

[0026] 1. The synthesis method does not require heating and cooling, and the target PMC can be obtained by reaction under normal temperature and pressure according to a certain ratio, which is suitable for rapid large-scale synthesis and production.

[0027] 2. The target PMC obtained by reaction has uniform particle size, an average particle size of 2 microns, and can be well dispersed in glue solution for subsequent coating and film forming to form a scintillator thin film with a specified size and thickness.

[0028] 3. The target PMC obtained by reaction has excellent optical performance and fully meets the actual needs of use as a scintillator.

[0029] 4. The finished powder is quickly obtained during the reaction preparation process.

[0030] 5. No anti-solvent is used in the preparation process, and the reaction waste liquid is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1is the dry powder prepared in Example One: where a is the appearance of the powder in daylight, b is the appearance of the powder under 302 nm UV light.

[0032] Figure 2 is the scintillator film prepared in Example One: where a is the appearance of the film in daylight, b is the appearance of the film under 302 nm UV light.

[0033] Figure 3 is the imaging of the scintillator film prepared in Example One under X-ray: where a is the imaging of the scintillator film prepared in Example One combined with TFT readout circuit under X-ray, b is the X-ray exposed sample of wireless Bluetooth earphone.

[0034] Figure 4 is the dry powder prepared in Example Four: where a is the appearance of the powder in daylight, b is the appearance of the powder under 365 nm UV light.

[0035] Figure 5 is the emission spectrum of the PMC dry powder prepared in Example Four.

[0036] Figure 6 is the imaging of the scintillator film prepared in Example Four under X-ray: where a is the imaging of the scintillator film prepared combined with TFT readout circuit under X-ray, b is the X-ray exposed sample of remote controller.

[0037] Figure 7 is the dry powder prepared in Example Seven.

[0038] Figure 8 is the scintillator film prepared in Example Seven: where a is the appearance of the film in daylight.

[0039] Figure 9 is the yield comparison chart when the A precursor is potassium chloride, and the solute mass in the A and B precursor solutions reaches different percentages of the solute mass in the saturated solution under the same conditions.

[0040] Figure 10 is the yield comparison chart when the A precursor is cesium chloride, and the solute mass in the A and B precursor solutions reaches different percentages of the solute mass in the saturated solution under the same conditions. DETAILED DESCRIPTION

[0041] The following are specific embodiments of the invention and further describe the technical solutions of the invention in conjunction with the accompanying drawings, but the invention is not limited to these embodiments. Reagents not specifically indicated in the present embodiment are known products, which are obtained by purchasing commercially available products.

[0042] Example 1 to Example 3 are all under normal pressure conditions, ambient temperature is 26 degrees Celsius, the relative humidity is 60 under the condition of reaction. And A precursor using potassium chloride (KCl) precursor.

[0043] Example 1:

[0044] 1. Preparation of potassium chloride (KCl) precursor solution: take 32 mmol of KCl into a beaker, add 7.75 mL of deionized water in the beaker, stir until KCl is fully dissolved.

[0045] 2. Preparation of cuprous chloride (CuCl) precursor solution: take 16 mmol of CuCl into a beaker, add 5 mL of hydrochloric acid (hydrochloric acid is purchased from China Pharmaceutical, concentration is 36-38%) and 0.6 mL of hypophosphoric acid stabilizer in the beaker, stir until CuCl is fully dissolved.

[0046] 3. Add the solution obtained in step 2 to the solution obtained in step 1, and K2CuCl3 powder precipitate can be obtained. The reaction equation is: CuCl + 2KCl = K2CuCl3. Therefore, the addition amount of potassium chloride and cuprous chloride is the molar ratio of complete reaction of A precursor halide and B precursor halide, that is, KCl: CuCl is 2:1.

[0047] 4. Repeat the washing and centrifugation of the powder precipitate obtained in step 3 with isopropyl alcohol to obtain a powder free of residual solvent in steps 1, 2.

[0048] 5. Dry the powder obtained in step 4 in a vacuum drying oven. The final powder is 2.02 grams.

[0049] 6. Take out 2g of the obtained powder and mix it with 2g of PDMS main agent and 0.2g of PDMS curing agent in a mold to cure into a film, and the final K2CuCl3 scintillator film is obtained.

[0050] Example 2:

[0051] 1. Preparation of potassium chloride (KCl) precursor solution: take 32 mmol of KCl into a beaker, add 20 mL of deionized water in the beaker, stir until KCl is fully dissolved.

[0052] 2. Preparation of cuprous chloride (CuCl) precursor solution: take 16 mmol of CuCl into a beaker, add 20 mL of hydrochloric acid (hydrochloric acid is purchased from China Pharmaceutical, concentration is 36-38%) and 0.6 mL of hypophosphoric acid stabilizer in the beaker, stir until CuCl is fully dissolved.

[0053] 3. Add the solution from step 2 to the solution from step 1, no K2CuCl3 powder precipitate is formed, the mixed solution is still a clear solution, no powder precipitate is formed.

[0054] Example 3:

[0055] 1. Preparation of KCl precursor solution: weigh 32 mmol of KCl into a beaker, add 10 mL of deionized water into the beaker, stir until KCl is fully dissolved.

[0056] 2. Preparation of CuCl precursor solution: weigh 16 mmol of CuCl into a beaker, add 5 mL of hydrochloric acid (hydrochloric acid is purchased from Sinopharm, concentration is 36-38%) and 0.6 mL of hypophosphorous acid stabilizer into the beaker, stir until CuCl is fully dissolved.

[0057] 3. Add the solution from step 2 to the solution from step 1, K2CuCl3 powder precipitate is formed.

[0058] 4. Repeat the washing and centrifugation of the powder precipitate from step 3 with ethyl acetate to obtain the powder without residual solvent from steps 1 and 2.

[0059] 5. Dry the powder from step 4 in a vacuum drying oven. The final powder is 1.59 grams.

[0060]

[0061] The above table is a data table of reactant concentrations and scintillator powder yield for examples 1 to 3. According to the concentration values of each precursor reaction solution and the scintillator powder yield values obtained in the above examples, it can be seen that under normal pressure conditions, the target scintillator powder can be directly obtained by mixing two saturated or nearly saturated precursor solutions under room temperature environment. This preparation method is simple and convenient to prepare under normal temperature and pressure conditions, and does not require heating or cooling during the preparation process, does not use anti-solvent, and reduces reaction waste liquid. This method is suitable for rapid large-scale synthesis and production.

[0062] II. In order to further illustrate the influence of temperature and humidity on the yield of the reaction product, the same formula as in example 1 is used for reaction, the only difference is the reaction temperature and humidity. The following table is the yield of product K2CuCl3 under different temperature and humidity. 3的 Yield comparison results.

[0063]

[0064] As shown in the table above, K2CuCl3 exhibits a certain yield under different temperatures and humidity levels, but the highest yield is achieved at room temperature (25°C) and humidity (55%). Therefore, this preparation method can be performed at room temperature and pressure without the need for heating or other additional preparation conditions.

[0065] III. To further illustrate the effect of the amount of stabilizer added on the reaction, the same formulation as in Example 1 was used for the reaction, except that the amount of stabilizer added was different.

[0066]

[0067] According to the table above, adding hypophosphite at a concentration of 1% or more of the B precursor halide salt yields a clear, transparent solution, and the resulting powder is also milky white, thus meeting the requirements. However, considering the economic and environmental benefits of the reactants, the optimal addition range is 1-10% of the B precursor halide salt mass, which ensures both a clear, transparent solution and a milky white powder product.

[0068] IV. To better understand the effect of the solubility of precursor solutions A and B on the product yield, the same formulation and reaction method as in Example 1 were used, except that the amounts of precursors A and B added to the precursor solutions were adjusted, i.e., the concentrations of precursor solutions A and B were changed. The specific operation was as follows: The molar mass content of the solute when the precursor solutions A and B reached complete saturation was set to 100% (in this example, specifically, 32 mmol of KCl was completely dissolved in 7.75 mL of deionized water; 16 mmol of CuCl was completely dissolved in 5 mL of hydrochloric acid and 0.6 mL of hypophosphoric acid). Then, the amounts of precursors A and B were adjusted. Specifically, for precursor solution A, KCl was added to 7.75 mL of deionized water at concentrations of 32 mmol * 90%, 32 mmol * 80%, and 32 mmol * 70%, respectively, to obtain near-saturated precursor solutions A at different concentrations. For the B precursor solution, 16 mmol*90%, 16 mmol*80%, and 16 mmol*70% were added to 5 mL of hydrochloric acid and 0.6 mL of hypophosphoric acid, respectively, to obtain near-saturated B precursor solutions of different concentrations. Then, various combinations of these different saturated and near-saturated solutions were performed to obtain the reactant yields under different concentration conditions, as shown in the table below. In the table below, each precursor is considered saturated when 100% is added.

[0069] Serial number KCl addition amount (%) CuCl addition amount (%) Yield (%) 1. 100 100 51 2. 100 90 49 3. 100 80 48 4. 100 70 46 5. 90 100 48 6. 80 100 45 7. 70 100 43 8. 80 80 46 9. 70 70 39

[0070] Depend on Figure 9As shown in the above table, the yield is the highest, reaching 51%, when KCl and CuCl are both saturated in the respective solvents. When the amount of the two precursors added accounts for 80% of the solute content of the saturated solution, the yield is still relatively high, reaching 46%. When the above values are lower than 80%, the yield is relatively low. In actual production, the solution needs to be saturated for the best result, and of course, the yield is also good when the amount of the precursors added accounts for more than 80% of the solute content of the saturated solution.

[0071] Five, Examples 4 to 6 below are all reacted under normal pressure conditions, with the ambient temperature being 26 degrees Celsius and the relative humidity being 60%. However, the A precursor is a cesium chloride (CsCl) precursor.

[0072] Example Four

[0073] 1. Preparation of the cesium chloride (CsCl) precursor solution: 12 mmol of CsCl was weighed into a sample bottle, 1.7 mL of deionized water was added to the sample bottle, and stirring was performed until the CsCl was fully dissolved.

[0074] 2. Preparation of the cuprous chloride (CuCl) precursor solution: 8 mmol of CuCl was weighed into a beaker, 2.5 mL of hydrochloric acid and 0.3 mL of hypophosphorous acid stabilizer were added to the beaker, and stirring was performed until the CuCl was fully dissolved.

[0075] 3. The solution obtained in step 2 was added to the solution obtained in step 1, and a Cs3Cu2Cl5 powder precipitate was obtained. The reaction formula is: 2CuCl + 3CsCl = Cs3Cu2Cl5. Therefore, the amount of cesium chloride and cuprous chloride added is the molar ratio of the complete reaction of the halide salt of the A precursor and the halide salt of the B precursor, i.e., CsCl:CuCl is 3:2.

[0076] 4. The powder precipitate obtained in step 3 was repeatedly washed with isopropyl alcohol and centrifuged to obtain a powder free of residual solvents in steps 1 and 2.

[0077] 5. The powder obtained in step 4 was dried in a vacuum drying box, and the final powder was 2.16 grams.

[0078] 6. 2 g of the obtained powder was taken out and mixed with 2 g of a PDMS main agent and 0.2 g of a PDMS curing agent in a mold to be cured into a film, and a final Cs3Cu2Cl5 scintillator thin film was obtained.

[0079] Example Five

[0080] 1. Preparation of the cesium chloride (CsCl) precursor solution: 120 mmol of CsCl was weighed into a sample bottle, 500 mL of deionized water was added to the sample bottle, and stirring was performed until the CsCl was fully dissolved.

[0081] 2. Preparation of cuprous chloride (CuCl) precursor solution: weigh 80 mmol of CuCl into a beaker, add 250 mL of hydrochloric acid and 3 mL of hypophosphorous acid stabilizer into the beaker, stir until the CuCl is fully dissolved.

[0082] 3. Add the solution obtained in step 2 to the solution obtained in step 1, and no Cs3Cu2Cl5 powder precipitate is obtained.

[0083] Example Six

[0084] 1. Preparation of cesium chloride (CsCl) precursor solution: weigh 12 mmol of CsCl into a sample bottle, add 2 mL of deionized water into the sample bottle, stir until the CsCl is fully dissolved.

[0085] 2. Preparation of cuprous chloride (CuCl) precursor solution: weigh 8 mmol of CuCl into a beaker, add 2.5 mL of hydrochloric acid and 0.3 mL of hypophosphorous acid stabilizer into the beaker, stir until the CuCl is fully dissolved.

[0086] 3. Add the solution obtained in step 2 to the solution obtained in step 1, and Cs3Cu2Cl5 powder precipitate is obtained.

[0087] 4. Repeat the washing and centrifugation of the powder precipitate obtained in step 3 using isopropanol, and obtain the powder without residual solvents in steps 1 and 2.

[0088] 5. Dry the powder obtained in step 4 in a vacuum drying oven, and finally obtain 1.19 grams of powder.

[0089] Yield comparison under different solution concentrations

[0090]

[0091] The above table is the comparison result of the scintillator powder yield under different solution concentrations in the preparation test of A precursor using cesium chloride and B precursor using cuprous chloride. According to the above table, when the A and B precursor solutions are in a saturated and near-saturated state, the scintillator powder can be directly synthesized at normal temperature and pressure, and the yield is higher than that of the reaction system of A precursor using potassium chloride (i.e. described in examples 1, 2 and 3).

[0092] Six, Example Seven

[0093] 1. Preparation of cesium chloride (CsCl) precursor solution: weigh 120 mmol of CsCl into a sample bottle, add 17 mL of deionized water into the sample bottle, stir until the CsCl is fully dissolved.

[0094] 2. Preparation of cuprous chloride (CuCl) precursor solution: Weigh 80 mmol of CuCl into a beaker, add 25 mL of hydrochloric acid and 3 mL of hypophosphorous acid stabilizer into the beaker, and stir until the CuCl is fully dissolved.

[0095] 3. Add the solution obtained in step 2 to the solution obtained in step 1 to obtain a Cs3Cu2Cl5 powder precipitate.

[0096] 4. Repeat the washing and centrifugation of the powder precipitate obtained in step 3 using isopropyl alcohol to obtain a powder free of residual solvents from steps 1 and 2.

[0097] 5. Dry the powder obtained in step 4 in a vacuum drying oven, and the final powder obtained is 21.848 g.

[0098] 6. Take 20 g of the obtained powder, mix it with 20 g of a PDMS main agent and 2 g of a PDMS curing agent in a mold, and cure it into a film to obtain a final Cs3Cu2Cl5 scintillator film.

[0099] This example seven is a synthesis test after enlarging the addition amount of the A precursor and the B precursor, which shows that the preparation method of the present application is also effective in large-scale synthesis and is suitable for mass production.

[0100] Seven, in order to better understand the influence of the solubility of the A precursor solution and the B precursor solution on the yield of the product, the same formula reaction of example four is also adopted, and the difference lies in adjusting the addition amount of the A precursor and the B precursor in the A precursor solution and the B precursor solution, that is, changing the concentration of the A precursor solution and the B precursor solution. The specific operation is as follows: the molar mass content of the solute when the A precursor solution and the B precursor solution reach a completely saturated state is set to 100% (at this time, this example is specifically that 12 mmol of CsCl is completely dissolved in 1.7 mL of deionized water; 8 mmol of CuCl is completely dissolved in 2.5 mL of hydrochloric acid and 0.3 mL of hypophosphorous acid). Then, the addition amount of the A precursor and the B precursor is adjusted respectively. Specifically, for the A precursor solution, 12 mmol*90%, 12 mmol*80%, and 12 mmol*70% of CsCl are added to 1.7 mL of deionized water respectively to obtain near-saturated A precursor solutions with different concentrations. For the B precursor solution, 8 mmol*90%, 8 mmol*80%, and 8 mmol*70% are added to 2.5 mL of hydrochloric acid and 0.3 mL of hypophosphorous acid respectively to obtain near-saturated B precursor solutions with different concentrations. Then, the above different saturated and near-saturated solutions are combined in pairs to obtain the yield of the reactants under different concentration conditions as shown in the following table. When the percentage of each precursor in the table is 100%, it is a saturated solution state.

[0101]

[0102]

[0103] By Figure 10 As shown in the above table, when CsCl and CuCl are saturated in their respective solvents, the yield is highest, reaching 77%. When the amount of the two precursors added is 80% of the solute content of the saturated solution, the yield is still relatively high, reaching 60%. When the amount of the two precursors added is less than 70% of the solute content of the saturated solution, the yield is significantly reduced. In actual production, the solution should be saturated for the best results, although the yield is still good when the amount of the two precursors added is greater than 70% of the solute content of the saturated solution.

[0104] All patents and publications mentioned in the specification are indicative of the levels of those skilled in the art to which the application pertains. All patents and publications are herein incorporated by reference to the same extent as if each individual publication was specifically and individually indicated to be incorporated by reference. The application described herein can be implemented in the absence of any element or elements, or in the presence of one or more of the elements, in the absence of one or more limitations or in the presence of one or more of the limitations, unless otherwise specifically stated. For example, the terms "comprising," "consisting essentially of and "consisting of" as used herein are each assignable to any of the two other terms. The term "one" as used herein means "one or more" unless otherwise specifically stated. The term "a" as used herein means "one or more" unless otherwise specifically stated. The terms and expressions which have been employed are used as terms of description and not of limitation, and there is no intention that in the use of such terms and expressions of describing the present application the patentee hereby disclaim any equivalents of the features shown and described except as set forth in the claims. It is recognized that certain embodiments of the application described herein are preferred and that others can be made without departing from the spirit and scope of the application. It is also recognized that other embodiments can be made and that logical changes can be made without departing from the spirit and scope of the application. It is also recognized that such equivalent features are intended to come within the scope of the application and the claims appended hereto.

Claims

1. A method for preparing a perovskite scintillator powder, characterized by, The specific steps are as follows: (1) Preparation of A precursor solution: weigh the required molar amount of A precursor halide salt, add a certain amount of deionized water or alcohol as solvent, so that it reaches saturation or near saturation state; (2) Preparation of B precursor solution: weigh the required molar amount of B precursor halide salt, add the corresponding solvent HX or NaX solution, so that it reaches saturation or near saturation state; X is one of Cl element, Br element or I element; the required molar amount of the above B precursor halide salt and the required molar amount of A precursor halide salt in step (1) are the molar ratio of complete reaction of A precursor halide salt and B precursor halide salt; (3) Under normal temperature and pressure conditions, quickly mix A and B precursor solutions to obtain corresponding perovskite microcrystal PMC precipitate; (4) Use alcohol or ester to continuously wash and centrifuge the perovskite microcrystal PMC precipitate obtained in step 3; (5) Dry the perovskite microcrystal PMC precipitate obtained in step 4 to obtain perovskite scintillator powder; The metal element in the A precursor halide salt in step (1) is one of Cs element, Rb element or K element; The metal element in the B precursor halide salt in step (2) is one of Cu element, Pb element, Mn element, Ag element or Zr element; In step 2, the B precursor halide salt solvent can also be added with a stabilizer, which is hypophosphorous acid, and the mass of hypophosphorous acid added is 1-10% of the mass of B precursor halide salt; The preparation reaction environment of steps 1, 2 and 3 is under normal pressure conditions, the air temperature is 25-35℃, and the humidity is 50-75 RH conditions, without heating and cooling; The near saturation state of A and B precursor solutions in steps (1) and (2) means that under the same conditions, the mass of solute in A and B precursor solutions is greater than or equal to 50% of the mass of A and B precursor solute in saturated solution.

2. The method of claim 1, wherein the perovskite scintillator powder is prepared by the steps of: preparing a solution of a metal halide; and adding a solution of an organic acid to the solution of the metal halide. When the A and B precursors in steps (1) and (2) are potassium chloride and cuprous chloride respectively, the near saturation state means that under the same conditions, the mass of solute in A and B precursor solutions is greater than or equal to 80% of the mass of A and B precursor solute in saturated solution.

3. A method of producing a perovskite scintillator powder according to any one of claims 1-2, characterized by, The alcohol is one of isopropyl alcohol, n-butanol or ethanol, and the ester is ethyl acetate, which is used to remove residual solvent and improve powder dispersibility.

4. The method of producing a perovskite scintillator according to any one of claims 1 to 3, characterized by, The solvent of the B precursor halide salt is a halide salt solution that can dissolve B and is miscible with the solvent of A precursor halide salt.

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