High-quality bismuth-based perovskite single crystal and preparation method and application thereof

Abstract

The application discloses high-quality bismuth-based perovskite monocrystals and a preparation method and application thereof. The preparation method of the high-quality bismuth-based perovskite monocrystals comprises the following steps: S1, preparing a single crystal growth precursor solution of the bismuth-based perovskite; S2, performing heat aging treatment on the prepared single crystal growth precursor solution; and S3, controlling the single crystal growth precursor solution after the heat aging treatment to crystallize and grow the bismuth-based perovskite monocrystals. The heat aging process of the precursor solution can obviously reduce the nucleation rate, effectively improve the crystallization quality, and finally obtain large-size high-quality bismuth-based perovskite monocrystals. The method has the advantages of simple process, strong operability, mild growth conditions, low required temperature, energy saving, low equipment requirement, low cost, high success rate, no need of additional seed crystals, and continuous growth of large-size high-quality perovskite monocrystals.

Description

Technical Field

[0001] This invention relates to the field of perovskite materials technology, and in particular to a high-quality bismuth-based perovskite single crystal, its preparation method, and its application. Background Technology

[0002] Organic-inorganic hybrid perovskites (OIHPs), represented by ABX3 (A = organic cation; B = metal; X = halogen), exhibit excellent optoelectronic properties in fields such as solar cells, photoelectric detection, high-energy ray detection, light-emitting diodes, and memory, making them a hot topic in materials science research in recent years. Compared to polycrystalline thin films, perovskite single crystals, due to their long-range structural order and absence of grain boundaries, possess longer carrier diffusion lengths and higher stability. Furthermore, lead-free bismuth-based perovskite single crystals are environmentally friendly, abundant, have high air stability, suitable band gaps (~2.0 eV), negligible ion migration effects, and high intrinsic resistivity, which are beneficial for realizing X-ray detection devices with both ultra-low detection limits and high performance. The lower the detection limit, the fewer X-rays needed to generate images of the same quality as existing ones, significantly reducing the harm of this high-energy ionizing radiation to patients requiring X-ray scanning imaging. Among them, bismuth-based halide perovskites show great potential for large-scale commercial applications in X-ray detectors.

[0003] Commercial large-area X-ray imaging requires large-size, high-quality perovskite single crystals, but their preparation remains a significant challenge. Wet chemical methods (or solution methods) are currently one of the common methods for preparing perovskite single crystals, offering simple equipment and low cost. Reports have shown that bismuth-based perovskite single crystals, with their defect-type structure, are highly prone to nucleation, exhibiting explosive nucleation during crystal growth. This results in crystals that are not only small in size but also difficult to control in quality. Therefore, the low-temperature solution method for growing large-size, high-quality bismuth-based perovskites requires strict control of the nucleation rate. Summary of the Invention

[0004] The main objective of this invention is to provide a high-quality bismuth-based perovskite single crystal, its preparation method, and its application, aiming to solve at least one of the aforementioned technical problems.

[0005] To achieve the above objectives, the present invention provides a method for preparing high-quality bismuth-based perovskite single crystals, comprising the following steps: S1: Prepare a single-crystal growth precursor solution for bismuth-based perovskite; S2: Perform thermal aging treatment on the prepared single crystal growth precursor solution; S3: Control the crystallization of the single crystal growth precursor solution after thermal aging treatment to grow bismuth-based perovskite single crystals.

[0006] Further, the specific operation process of step S1 is as follows: CH3NH3X and BiX3 are added to the solvent, wherein X is any one or more of I, Br, and Cl, and stirred to dissolve, thereby obtaining a single crystal growth precursor solution.

[0007] Furthermore, in step S1, the ratio of CH3NH3X, BiX3 and solvent is 0.006–0.06 mol: 0.02 mol: 10–30 mL.

[0008] Further, in step S1, the solvent is selected from any one or more of γ-butyrolactone, N,N-dimethylformamide, and dimethyl sulfoxide.

[0009] Furthermore, the specific operation process of step S2 is as follows: the container containing the single crystal growth precursor solution is sealed and heated at a constant temperature and left to stand.

[0010] Furthermore, in step S2, the constant temperature heating and static setting temperature is 40-200℃, and the time is 48 hours to 3 weeks.

[0011] Further, the specific operation process of step S3 is as follows: the container containing the single crystal growth precursor solution after heat aging treatment is opened, and constant temperature evaporation treatment is performed to crystallize and grow bismuth-based perovskite single crystal (CH3NH3). a Bi b X a+3b X is any one or more of I, Br, and Cl, and the ratio of a, b and a+3b is 3:2:9, 1:1:4, 1:3:10, 1:2:7, 3:1:6 or 2:1:5.

[0012] Furthermore, in step S3, the constant temperature evaporation is 50–70°C, and the time is 3–10 days.

[0013] The present invention also provides a large-size, high-quality bismuth-based perovskite single crystal, which is prepared according to the above preparation method.

[0014] The present invention also provides an application of the above-mentioned large-size, high-quality bismuth-based perovskite single crystal in solar cells, photoelectric detection, high-energy ray detection, light-emitting diodes, or memory.

[0015] The beneficial effects of this invention are reflected in: 1. The present invention can significantly reduce the nucleation rate and effectively improve the crystallization quality through the thermal aging process of the precursor liquid, and finally obtain large-size, high-quality bismuth-based perovskite single crystals. 2. The method of the present invention is simple and highly operable; the growth conditions are mild, the required temperature is low, and energy is saved; the equipment requirements are low and the cost is low; the success rate is high; no additional seed crystal is required, and continuous growth of large-size, high-quality perovskite single crystals can be achieved.

[0016] 3. The large-size, high-quality bismuth-based perovskite single crystal material prepared by this method is expected to provide a key material foundation for the development of high-performance perovskite single crystal optoelectronic devices, especially X-ray detectors with ultra-low detection limits. At the same time, it also provides a good theoretical research platform for studying the intrinsic photoelectric properties of such perovskite materials. Attached Figure Description

[0017] Figure 1 The image shows a photograph of the (CH3NH3)3Bi2I9 perovskite single crystal prepared in Example 1. The smallest grid size in the graph paper in the image is 1 mm * 1 mm.

[0018] Figure 2 The image shows a photograph of the (CH3NH3)3Bi2I9 perovskite single crystal prepared in Example 2. The smallest grid size in the graph paper in the image is 1 mm * 1 mm.

[0019] Figure 3 The following are the XRD patterns of the (CH3NH3)3Bi2I9 perovskite single crystal obtained in Example 2: (a) XRD pattern of the upper surface, which is the (002) crystal plane; (b) X-ray diffraction rocking curve.

[0020] Figure 4 This is a photograph of the (CH3NH3)3Bi2I9 perovskite crystal prepared in Comparative Example 1. The smallest grid size in the grid paper in the figure is 1 mm * 1 mm.

[0021] Figure 5 This is a comparison diagram of the dark-state current of the single-crystal Au / OIHP / Au vertical devices prepared in Comparative Example 1 (black) and Example 3 (red). The Au / OIHP / Au vertical device was prepared by thermally depositing gold electrodes on the upper and lower surfaces of the obtained (CH3NH3)3Bi2I9 single crystal. Detailed Implementation

[0022] To enable those skilled in the art to more clearly understand the technical solutions described in this invention, the following embodiments are provided for illustration. It should be noted that the following embodiments do not constitute a limitation on the scope of protection claimed by this invention.

[0023] Unless otherwise specified, the raw materials, reagents or devices used in the following embodiments can be obtained from conventional commercial sources or by existing known methods; unless otherwise specified, the methods used in the embodiments of the present invention are methods mastered by those skilled in the art.

[0024] Example 1 Preparation of high-quality bismuth-based perovskite single crystals The preparation method is as follows: Step S1: Add 0.013 mol of CH3NH3I and 0.02 mol of BiI3 to 20 mL of γ-butyrolactone, stir and dissolve at room temperature for 24 h to obtain a clear and transparent single crystal growth precursor solution.

[0025] Step S2: Filter the single crystal growth precursor solution (using a 0.45μm polytetrafluoroethylene filter head, the same below) into a crystallizing dish and seal it with metal foil. Then place it in a heated drying oven at 56℃ and let it stand at a constant temperature for 3 weeks.

[0026] Step S3: Make several holes in the tin foil for solvent evaporation, and continue to evaporate at a constant temperature of 56°C in a heated drying oven for 10 days to obtain bismuth-based perovskite single crystal (CH3NH3)3Bi2I9.

[0027] Example 2 Preparation of high-quality bismuth-based perovskite single crystals The preparation method is as follows: Step S1: Add 0.013 mol of CH3NH3I and 0.02 mol of BiI3 to 20 mL of γ-butyrolactone, stir and dissolve at room temperature for 24 h to obtain a clear and transparent single crystal growth precursor solution.

[0028] Step S2: Filter the single crystal growth precursor solution into a crystallizing dish and seal it with tin foil. Then place it in a heated drying oven at 56°C and let it stand at a constant temperature for 10 days.

[0029] Step S3: Make several holes in the tin foil for solvent evaporation, and continue to evaporate at a constant temperature of 56°C in a heated drying oven for 10 days to obtain bismuth-based perovskite single crystal (CH3NH3)3Bi2I9.

[0030] Example 3 Preparation of large-size, high-quality bismuth-based perovskite single crystals The preparation method is as follows: Step S1: Add 0.013 mol of CH3NH3I and 0.02 mol of BiI3 to 20 mL of γ-butyrolactone solvent, stir and dissolve at room temperature for 24 h to obtain a clear and transparent single crystal growth precursor solution.

[0031] Step S2: Filter the single crystal growth precursor solution into a crystallizing dish and seal it with tin foil. Then place it in a heated drying oven at 65°C and let it stand at a constant temperature for 5 days.

[0032] Step S3: Make several holes in the tin foil for solvent evaporation, and continue to evaporate at a constant temperature of 60°C in a heated drying oven for 6 days to obtain bismuth-based perovskite single crystal (CH3NH3)3Bi2I9.

[0033] Example 4 Preparation of large-size, high-quality bismuth-based perovskite single crystals The preparation method is as follows: Step S1: Add 0.06 mol of CH3NH3I and 0.02 mol of BiI3 to 25 mL of γ-butyrolactone solvent, stir and dissolve at room temperature for 24 h to obtain a clear and transparent single crystal growth precursor solution.

[0034] Step S2: Filter the single crystal growth precursor solution into a crystallizing dish and seal it with tin foil. Then place it in a heated drying oven at 56°C and let it stand at a constant temperature for 10 days.

[0035] Step S3: Make several holes in the tin foil for solvent evaporation, and continue to evaporate at a constant temperature of 56°C in a heated drying oven for 10 days to obtain bismuth-based perovskite single crystal (CH3NH3)3Bi2I9.

[0036] Example 5 Preparation of large-size, high-quality bismuth-based perovskite single crystals The preparation method is as follows: Step S1: Add 0.013 mol of CH3NH3I and 0.02 mol of BiI3 to 20 mL of N,N-dimethylformamide solvent, stir and dissolve at room temperature for 24 h to obtain a clear and transparent single crystal growth precursor solution.

[0037] Step S2: Filter the single crystal growth precursor solution into a crystallizing dish and seal it with metal foil. Then place it in a heated drying oven at 56°C and let it stand at a constant temperature for one week.

[0038] Step S3: Make several holes in the metal foil for solvent evaporation, and continue to evaporate at a constant temperature of 56°C in a heated drying oven for 6 days to obtain bismuth-based perovskite single crystal (CH3NH3)3Bi2I9.

[0039] Example 6 Preparation of large-size, high-quality bismuth-based perovskite single crystals The preparation method is as follows: Step S1: Add 0.06 mol of CH3NH3I and 0.02 mol of BiI3 to 25 mL of dimethyl sulfoxide solvent, stir and dissolve at room temperature for 24 h to obtain a clear and transparent single crystal growth precursor solution.

[0040] Step S2: Filter the single crystal growth precursor solution into a crystallizing dish and seal it with metal foil. Then place it in a heated drying oven at 56°C and let it stand at a constant temperature for one week.

[0041] Step S3: Make several holes in the metal foil for solvent evaporation, and continue to evaporate at a constant temperature of 56°C in a heated drying oven for 6 days to obtain bismuth-based perovskite single crystal (CH3NH3)3Bi2I9.

[0042] Comparative Example 1 Comparison of the preparation of bismuth-based perovskite single crystals The preparation method is as follows: Step S1: Add 0.013 mol of CH3NH3I and 0.02 mol of BiI3 to 20 mL of γ-butyrolactone, stir and dissolve at room temperature for 24 h to obtain a clear and transparent single crystal growth precursor solution, then filter it into a crystallizing dish and seal it with metal foil.

[0043] Step S2: Filter the single crystal growth precursor solution into a crystallizing dish and seal it with metal foil. Make several holes in the metal foil to allow solvent evaporation. Place it in a heated drying oven at 56°C for constant temperature evaporation for 10 days to obtain a comparative bismuth-based perovskite single crystal (CH3NH3)3Bi2I9.

[0044] Experimental Example 1 Structural and property analysis of perovskite single crystals Figure 1 This is a photograph of the (CH3NH3)3Bi2I9 perovskite single crystal obtained in Example 1.

[0045] Figure 2 This is a photograph of the (CH3NH3)3Bi2I9 perovskite single crystal obtained in Example 2.

[0046] Figure 3 (a) is the XRD curve of the upper surface of the (CH3NH3)3Bi2I9 perovskite single crystal obtained in Example 2, which is the (002) crystal plane; Figure 3 (b) is its X-ray diffraction rocking curve, with an FWHM value of only 0.021°.

[0047] Figure 4 This is a photograph of the (CH3NH3)3Bi2I9 perovskite crystal prepared in Comparative Example 1.

[0048] Figure 5 This is a comparison of the dark-state currents of the single-crystal Au / OIHP / Au vertical devices in Comparative Example 1 (black) and Example 2 (red). It can be seen that the dark-state current of the corresponding single-crystal devices is significantly reduced after thermal aging treatment.

[0049] By comparing the preparation results of Examples 1, 2, and Comparative Example 1, it can be seen that the precursor solution in Examples 1 and 2 underwent thermal aging treatment, while Comparative Example 1 did not undergo thermal aging treatment. As a result, Examples 1 and 2 both obtained bismuth-based perovskite single crystals with large size, smooth and flat surface, high crystallinity, high resistivity, and low dark current, while Comparative Example 1 obtained a large number of bismuth-based perovskite crystals with small particle size and poor quality. It can be seen that the thermal aging treatment of the precursor solution effectively reduces the nucleation rate during the crystallization of bismuth-based perovskite and improves the crystallization quality, resulting in the final formation of large-size, high-quality bismuth-based perovskite single crystals.

[0050] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing high-quality bismuth-based perovskite single crystals, characterized in that, Includes the following steps: S1: Prepare a single-crystal growth precursor solution for bismuth-based perovskite; S2: Perform thermal aging treatment on the prepared single crystal growth precursor solution; S3: Control the crystallization of the single crystal growth precursor solution after thermal aging treatment to grow bismuth-based perovskite single crystals.

2. The method for preparing high-quality bismuth-based perovskite single crystals as described in claim 1, characterized in that, The specific operation process of step S1 is as follows: CH3NH3X and BiX3 are added to the solvent, where X is any one or more of I, Br, and Cl, and stirred to dissolve, thereby obtaining a single crystal growth precursor solution.

3. The method for preparing high-quality bismuth-based perovskite single crystals as described in claim 2, characterized in that, In step S1, the ratio of CH3NH3X, BiX3 and solvent is 0.006–0.06 mol: 0.02 mol: 10–30 mL.

4. The method for preparing high-quality bismuth-based perovskite single crystals as described in claim 2, characterized in that, In step S1, the solvent is selected from any one or more of γ-butyrolactone, N,N-dimethylformamide, and dimethyl sulfoxide.

5. The method for preparing high-quality bismuth-based perovskite single crystals as described in any one of claims 1 to 4, characterized in that, The specific operation process of step S2 is as follows: seal the container containing the single crystal growth precursor solution, heat it at a constant temperature and let it stand.

6. The method for preparing high-quality bismuth-based perovskite single crystals as described in claim 5, characterized in that, In step S2, the constant temperature heating and static setting temperature is 40-200℃, and the time is 48 hours to 3 weeks.

7. The method for preparing high-quality bismuth-based perovskite single crystals as described in any one of claims 1 to 4, characterized in that, The specific operation process of step S3 is as follows: open the container containing the single crystal growth precursor solution after heat aging treatment, perform constant temperature evaporation treatment, and crystallize to obtain bismuth-based perovskite single crystal (CH3NH3). a Bi b X a+3b X is any one or more of I, Br, and Cl, and the ratio of a, b and a+3b is 3:2:9, 1:1:4, 1:3:10, 1:2:7, 3:1:6 or 2:1:

5.

8. The method for preparing high-quality bismuth-based perovskite single crystals as described in any one of claims 1 to 4, characterized in that, In step S3, the constant temperature evaporation is 50–70°C, and the time is 3–10 days.

9. A high-quality bismuth-based perovskite single crystal, characterized in that, Prepared according to the preparation method described in any one of claims 1 to 8.

10. The application of the high-quality bismuth-based perovskite single crystal as described in claim 9 in solar cells, photoelectric detectors, high-energy ray detectors, light-emitting diodes, or memory.

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