FeI2-doped CsCu2I3 single crystal as well as preparation method and application thereof

Abstract

The invention discloses a FeI2-doped CsCu2I3 single crystal as well as a preparation method and application thereof, and belongs to the field of single crystal preparation, the preparation method comprises the following steps: uniformly mixing CsI powder, CuI powder and FeI2 powder to obtain a mixed material, and placing the mixed material in a container; the preparation method comprises the following steps: preparing dimethylformamide, dimethyl sulfoxide and oleic acid according to a volume ratio of 4.5: 1.5: 1.5 to obtain a first mixed solution; adding the first mixed solution into the mixed material, and stirring at 50-150 DEG C for 12 hours to prepare a second mixed solution; putting the second mixed solution into an injector, and filtering powder which cannot be fully dissolved by using a 0.45 mu m filter membrane to obtain a third mixed solution; and carrying out crystal growth on the third mixed solution under a constant temperature condition. According to the preparation method disclosed by the invention, the FeI2-doped CsCu2I3 single crystal of which the size can reach the centimeter level is successfully prepared by optimizing a solvent system, doping concentration and crystal growth conditions.

Description

Technical Field

[0001] The invention relates to the field of single crystal preparation, and in particular to a FeI2-doped CsCu2I3 single crystal, a preparation method and application thereof. Background Art

[0002] Scintillator materials are a type of functional material that can convert high-energy rays (such as X-rays, gamma rays) or particle radiation into visible light. They are widely used in medical imaging, nondestructive testing, nuclear radiation detection and other fields. With the rapid development of high-performance imaging and detection technology, higher requirements are placed on the performance of scintillator materials, including high light yield, fast response, high quantum efficiency, and excellent thermal and chemical stability. However, traditional scintillator materials (such as BGO, CsI:Tl, etc.) have certain limitations in terms of light yield, response speed and preparation cost, and it is difficult to meet the needs of the new generation of high-sensitivity imaging and detection equipment.

[0003] In recent years, metal halide-based scintillator materials have attracted widespread attention due to their excellent optical properties and low preparation costs. Among them, CsCu2I3, as a new type of inorganic lead-free metal halide material, has high light yield, good thermal stability and environmental friendliness, and has become a hot spot in scintillator material research. However, CsCu2I3 single crystals still face some problems in practical applications, such as small crystal size, low quantum yield, and scintillation performance needs to be further improved. In addition, the research on doping modification of CsCu2I3 single crystals is still in its initial stage, especially in the preparation of large-size single crystals and performance optimization, and a mature preparation process technology solution has not yet been formed. Summary of the invention

[0004] One of the purposes of the present invention is to provide a method for preparing FeI2-doped CsCu2I3 single crystals to solve the shortcomings of the prior art such as small crystal size and low quantum yield.

[0005] The present invention is achieved through the following technical solutions. A preparation method of a CsCu2I3 single crystal doped with FeI2 includes the following steps: S100: Uniformly mix CsI powder, CuI powder, and FeI2 powder to obtain a mixed material and place the mixed material in a container; S200: Prepare a first mixed solution by configuring dimethylformamide (DMF), dimethyl sulfoxide (DMSO), and oleic acid (OA) according to a volume ratio of 4.5:1.5:1.5; S300: Add the first mixed solution to the mixed material and stir for 12 hours while maintaining the temperature at 50 - 150 °C to prepare a second mixed solution; S400: Place the second mixed solution in a syringe and filter the powder that cannot be fully dissolved using a 0.45 μm filter membrane to obtain a third mixed solution; S500: Place the third mixed solution under a constant temperature condition for crystal growth.

[0006] Further, the molar ratio of CsI powder, CuI powder, and FeI2 powder is 4:8:0.005 - 0.02.

[0007] Further, the temperature of the constant temperature condition is 50 - 150 °C.

[0008] Further, the crystal growth time is 20 days, and finally, a FeI2 single crystal with a maximum size of 2 cm is obtained.

[0009] Further, the doping molar fraction of FeI2 is 0.5% - 2%.

[0010] On the other hand, the present invention provides a CsCu2I3 single crystal doped with FeI2, and the CsCu2I3 single crystal is prepared according to the preparation method described above.

[0011] Further, the optimal doping quantum yield of the CsCu2I3 single crystal doped with FeI2 is 42%.

[0012] Further, the CsCu2I3 single crystal has a wide - band emission characteristic under high - energy ray excitation, the emission wavelength range is 400 nm - 700 nm, the central emission peak is located at 570 nm, and it emits yellow light.

[0013] The present invention also provides an application of a CsCu2I3 single crystal doped with FeI2, and the CsCu2I3 single crystal has the following applications: (1) Application in X - ray imaging; (2) Application in medical imaging; (3) Application in nuclear radiation detection; (4) Application in non - destructive testing; (5) Application in the preparation of high - power and high - sensitivity photodetectors; (6) Application in the preparation of high - power and high - sensitivity scintillator materials.

[0014] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0015] 1. The present invention optimizes the performance of CsCu2I3 single crystals through the method of FeI2 doping modification. By doping, the energy band structure, defect state distribution, and optical properties of the crystals are effectively regulated, thereby improving their quantum yield and scintillation performance.

[0016] 2. By optimizing the solvent system, doping concentration, and crystal growth conditions, the present invention successfully prepares FeI2-doped CsCu2I3 single crystals with a size up to centimeter scale. Experiments show that doping FeI2 not only significantly improves the quantum yield and light yield of the single crystals but also enhances their scintillation performance, making them have broad application prospects in fields such as X-ray imaging and non-destructive testing.

[0017] 3. The light yield of the FeI2-doped CsCu2I3 single crystal material prepared by the present invention is significantly higher than that of traditional scintillator materials, meeting the requirements of high-sensitivity detection. It has excellent performance especially in X-ray imaging and nuclear radiation detection. Prepared by the low-temperature solution method, the process is simple and the cost is low. It can realize the growth of centimeter-scale lead-free perovskite single crystals, providing a new idea for the growth size of lead-free perovskite single crystals, suitable for large-scale industrial production, significantly reducing the production cost. In addition, compared with other perovskite materials, this material does not contain lead, avoiding the potential harm of lead to the environment and human body, and having higher environmental friendliness and safety.

[0018] 4. The FeI2-doped CsCu2I3 single crystal material of the present invention not only has better optical performance than existing commercial scintillator materials. Experiments show that its scintillation performance is more than 3 times higher than that of commercial BGO (bismuth germanate), and the X-ray detection dose rate can reach 8.75 μGy / s, meeting the requirements of high-performance scintillators in fields such as industrial non-destructive testing and medical imaging, and being able to meet the technical requirements of the next generation of high-performance imaging and detection equipment. It provides a new solution for the development and application of high-efficiency scintillator materials, has broad application prospects, and can be widely used in fields such as X-ray imaging, non-destructive testing, nuclear radiation detection, and medical imaging. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, form a part of this application, and do not limit the embodiments of the present invention. In the drawings:

[0020] Figure 1 is a physical diagram of the FeI2-doped CsCu2I3 single crystal material provided in Embodiment 1 of the present invention under sunlight.

[0021] Figure 2 is the emission diagram of the FeI2-doped CsCu2I3 single crystal material provided in Embodiment 1 of the present invention under different excitation conditions.

[0022] Figure 3 The physical diagram of the CsCu2I3 single crystal material doped with FeI2 provided in Embodiment 3 of the present invention under 365 nm ultraviolet light.

[0023] Figure 4 The emission spectra of the CsCu2I3-1% Fe material provided in Embodiment 3 of the present invention under excitations at 570 nm and 325 nm.

[0024] Figure 5 The PLQY spectrum provided in Embodiment 3 of the present invention.

[0025] Figure 6 The comparative RL map of the single crystal material provided in Embodiment 3 of the present invention and commercial BGO.

[0026] Figure 7 The low-dose linear fitting diagram of the single crystal material provided in Embodiment 3 of the present invention under X-rays.

[0027] Figure 8 The XRD diagrams of the materials in Examples 1-5 provided in the experimental examples of the present invention.

[0028] Figure 9 The emission spectra of the materials in Examples 1-5 provided in the experimental examples of the present invention under 325 nm light excitation.

[0029] Figure 10 The CIE diagrams of the materials in Examples 1-5 provided in the experimental examples of the present invention. Detailed implementation manners

[0030] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some but not all of the embodiments of the present invention.

[0031] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Although this invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein can also be used in the implementation or testing of this invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the said documents. In case of conflict with any incorporated document, the content of this specification shall prevail. Regarding the use of "comprising", "including", "having", "containing", etc. in this text, they are all open-ended terms, meaning including but not limited to. Unless the context clearly indicates otherwise, the expressions "a" and "an" used herein include plural referents. It should be noted that "first", "second", etc. are only for convenience of description and easy distinction, and cannot be construed as indicating or implying relative importance. The term "about" used herein represents a range of ±20% of the value following it. In some embodiments, the term "about" represents a range of ±10% of the value following it. In some embodiments, the term "about" represents a range of ±5% of the value following it.

[0032] Example 1

[0033] (1) According to the chemical composition CsI:CuI = 4:8, weigh the required raw materials, including CsI powder and CuI powder. After fully mixing the weighed powders evenly, place them in a 30 mL glass bottle for standby;

[0034] (2) Dissolve the evenly mixed raw materials in a mixed solvent composed of dimethylformamide (DMF), dimethyl sulfoxide (DMSO) and oleic acid (OA). The volume ratio of the three is 4.5:1.5:1.5. Place it under the condition of 50 - 150 °C and stir for 12 hours to ensure the uniformity of the solution;

[0035] (3) Filter the stirred solution through a 0.45 μm filter membrane to remove the powders that are not fully dissolved, and obtain a light green solution;

[0036] (4) Place the filtered solution under the constant temperature condition of 50 - 150 °C, and induce crystal growth by solvent evaporation or temperature gradient. The crystal growth time is 20 days, and finally obtain CsCu2I3 single crystals. Figure 1 The physical picture of the CsCu2I3 single crystal material doped with FeI2 prepared by the method in this example under sunlight is shown. It can be seen from the figure that the crystal size prepared in this example is centimeter-scale (up to 2 cm at most).

[0037] Figure 2 The emission diagram of the crystal prepared in the example under excitation at different wavelength illuminations (250 nm - 350 nm) is shown.

[0038] Example 2

[0039] (1)According to the chemical composition CsI:CuI:FeI2 = 4:8:0.05, weigh the required raw materials, including CsI powder, CuI powder and FeI2 powder. After mixing the weighed powders evenly, place them in a 30 mL glass bottle for standby;

[0040] (2)Dissolve the evenly mixed raw materials in a mixed solvent composed of dimethylformamide (DMF), dimethyl sulfoxide (DMSO) and oleic acid (OA). The volume ratio of the three is 4.5:1.5:1.5. Place it under the condition of 50 - 150 °C and stir for 12 hours to ensure the solution is uniform;

[0041] (3)Filter the evenly stirred solution through a 0.45 μm filter membrane to remove the powders that are not fully dissolved, and obtain a light green solution;

[0042] (4)Place the filtered solution under the constant temperature condition of 50 - 150 °C, and induce crystal growth through solvent evaporation or temperature gradient. The crystal growth time is 20 days, and finally obtain CsCu2I3 - 0.5% Fe single crystal.

[0043] Example 3

[0044] (1)According to the chemical composition CsI:CuI:FeI2 = 4:8:0.1, weigh the required raw materials, including CsI powder, CuI powder and FeI2 powder. After mixing the weighed powders evenly, place them in a 30 mL glass bottle for standby;

[0045] (2)Dissolve the evenly mixed raw materials in a mixed solvent composed of dimethylformamide (DMF), dimethyl sulfoxide (DMSO) and oleic acid (OA). The volume ratio of the three is 4.5:1.5:1.5. Place it under the condition of 50 - 150 °C and stir for 12 hours to ensure the solution is uniform;

[0046] (3)Filter the evenly stirred solution through a 0.45 μm filter membrane to remove the powders that are not fully dissolved, and obtain a light green solution;

[0047] (4)Place the filtered solution under the constant temperature condition of 50 - 150 °C, and induce crystal growth through solvent evaporation or temperature gradient. The crystal growth time is 20 days, and finally obtain CsCu2I3 - 1% Fe single crystal.

[0048] Figure 3 The physical diagram of the crystal material prepared in this example under the irradiation of a 365 nm ultraviolet lamp is shown.

[0049] Figure 4The emission spectra of the crystal material prepared in this example under the excitation of light with wavelengths of 570 nm and 325 nm are shown.

[0050] Figure 5 The PLQY spectrum of the crystal material prepared in this example is shown.

[0051] The RL spectrum comparing the crystal material prepared in this example with commercially available BGO is as Figure 6 shown.

[0052] Figure 7 The low-dose linear fitting diagram of the crystal material prepared in this example under X-rays is shown.

[0053] It can be seen from the preparation method and the legends in this example that when the doping molar fraction of FeI2 is 1%, the prepared crystal material has the best performance.

[0054] Example 4

[0055] (1) According to the chemical composition CsI:CuI:FeI2 = 4:8:0.15, weigh the required raw materials, including CsI powder, CuI powder and FeI2 powder. After fully mixing the weighed powders evenly, place them in a 30 mL glass bottle for standby;

[0056] (2) Dissolve the evenly mixed raw materials in a mixed solvent composed of dimethylformamide (DMF), dimethyl sulfoxide (DMSO) and oleic acid (OA). The volume ratio of the three is 4.5:1.5:1.5. Place it under the condition of 50 - 150 °C and stir for 12 hours to ensure the solution is uniform;

[0057] (3) Filter the stirred solution through a 0.45 μm filter membrane to remove the powders that are not fully dissolved, and obtain a light green solution;

[0058] (4) Place the filtered solution under the constant temperature condition of 50 - 150 °C, and induce crystal growth by solvent evaporation or temperature gradient. The crystal growth time is 20 days, and finally obtain CsCu2I3 - 1.5% Fe single crystal.

[0059] Example 5

[0060] (1) According to the chemical composition CsI:CuI:FeI2 = 4:8:0.2, weigh the required raw materials, including CsI powder, CuI powder and FeI2 powder. After fully mixing the weighed powders evenly, place them in a 30 mL glass bottle for standby;

[0061] (2) Dissolve the uniformly mixed raw materials in a mixed solvent composed of dimethylformamide (DMF), dimethyl sulfoxide (DMSO), and oleic acid (OA), with a volume ratio of the three being 4.5:1.5:1.5. Place it under stirring at 50 - 150 °C for 12 hours to ensure the uniformity of the solution;

[0062] (3) Filter the uniformly stirred solution through a 0.45 μm filter membrane to remove the undissolved powder completely, and obtain a light green solution;

[0063] (4) Place the filtered solution under a constant temperature condition of 50 - 150 °C, and induce crystal growth through solvent evaporation or temperature gradient. The crystal growth time is 20 days, and finally obtain CsCu2I3 - 2% Fe single crystal.

[0064] Experimental Example

[0065] Test the CsCu2I3 single crystal materials with different doping mole fractions of FeI2 prepared in Examples 1 - 5, and the obtained XRD patterns of the materials are as Figure 8 shown.

[0066] Excite the CsCu2I3 single crystal materials with different doping mole fractions of FeI2 prepared in Examples 1 - 5 using light with a wavelength of 325 nm, and record the obtained emission spectra as Figure 9 shown.

[0067] Test the photo - to - luminescence performance of the CsCu2I3 single crystal materials with different doping mole fractions of FeI2 prepared in Examples 1 - 5, and the plotted CIE diagrams are as Figure 10 shown.

[0068] The specific embodiments described above further elaborate on the purpose, technical solutions, and beneficial effects of the present invention. It should be understood that the above - mentioned are only specific embodiments of the present invention and are not used to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing FeI2-doped CsCu2I3 single crystal, characterized in that: The preparation method comprises: S100: uniformly mix CsI powder, CuI powder and FeI2 powder to obtain a mixed material and place the mixed material in a container; S200, preparing a first mixed solution by mixing dimethylformamide, dimethyl sulfoxide and oleic acid in a volume ratio of 4.5:1.5:1.5; S300, adding the first mixed solution to the mixed material, and stirring for 12 hours at 50-150° C. to prepare a second mixed solution; S400, placing the second mixed solution in a syringe, and filtering the powder that cannot be fully dissolved using a 0.45 μm filter membrane to obtain a third mixed solution; S500, placing the third mixed solution under a constant temperature condition to perform crystal growth.

2. The method for preparing FeI2-doped CsCu2I3 single crystal according to claim 1, characterized in that: The molar ratio of the CsI powder, CuI powder and FeI2 powder is 4:8:0.005-0.

02.

3. The method for preparing FeI2-doped CsCu2I3 single crystal according to claim 1, characterized in that: The temperature of the constant temperature condition is: 50~150℃.

4. The method for preparing FeI2-doped CsCu2I3 single crystal according to claim 1, characterized in that: The preparation method comprises: the crystal growth time is 20 days, and finally a FeI2 single crystal with a maximum size of 2 cm is obtained.

5. The method for preparing FeI2-doped CsCu2I3 single crystal according to claim 1, characterized in that: The doping molar fraction of the FeI2 is 0.5%-2%.

6. A FeI2-doped CsCu2I3 single crystal, characterized in that: The CsCu2I3 is prepared according to any one of the preparation methods of claims 1 to 5.

7. The FeI2-doped CsCu2I3 single crystal according to claim 6, characterized in that: The quantum yield of the CsCu2I3 single crystal is 42%.

8. The FeI2-doped CsCu2I3 single crystal according to claim 6, characterized in that: The CsCu2I3 single crystal has a wide-band emission characteristic under high-energy ray excitation, the emission wavelength range is 400 nm to 700 nm, the central emission peak is located at 570 nm, and it appears as yellow light.

9. An application of FeI2-doped CsCu2I3 single crystal, characterized in that: The CsCu2I3 single crystal includes the following applications: (1) Application in X-ray imaging; (2) Application in medical imaging; (3) Application in nuclear radiation detection; (4) Application in non-destructive testing; (5) Application in the preparation of high-power and high-sensitivity photodetectors; (6) Application in the preparation of high-power, high-sensitivity scintillator materials.

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