X-ray detector for growing perovskite single crystal based on mixed solvent system of 2-methoxyethanol and acetonitrile and preparation method of X-ray detector
By using a mixed solvent system of 2-methoxyethanol and acetonitrile combined with a reverse temperature growth method, MAPbI3 single crystals with ultra-low defect state density were grown, solving the problem of solvent residue in perovskite single crystal growth. This resulted in an X-ray detector with high sensitivity and low dark current, exhibiting good stability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- JILIN UNIVERSITY
- Filing Date
- 2026-02-04
- Publication Date
- 2026-05-01
AI Technical Summary
The existing technology lacks systematic and in-depth research on the role mechanism of solvents, cluster behavior and their impact on crystal defects and solvent residues during the growth of perovskite single crystals, resulting in poor crystal quality and affecting the performance of optoelectronic devices.
By using a mixed solvent system of 2-methoxyethanol and acetonitrile combined with a reverse-temperature growth method, MAPbI3 single crystals with ultra-low defect state density were grown. This was achieved by using 2-methoxyethanol with virtually no residue and acetonitrile to break the internal hydrogen bond network, thereby improving solute transport capacity. These crystals were then used to fabricate X-ray detectors.
A high-sensitivity and low-dark-current X-ray detector with low voltage was achieved, which maintained stability for 15 hours of continuous operation, with excellent crystal quality and low defect state density.
Smart Images
Figure CN121968981A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of X-ray detector technology, specifically relating to an X-ray detector based on a mixed solvent system of 2-methoxyethanol and acetonitrile for growing perovskite single crystals and its preparation method. Background Technology
[0002] Lead halide perovskite materials have attracted widespread attention in the field of novel optoelectronic devices due to their excellent optoelectronic properties. Compared with polycrystalline thin films, perovskite single crystals have fewer defects and grain boundaries, better crystal quality, and longer carrier diffusion lengths, showing significant performance potential in radiation detection, photoelectric detection, photovoltaics, and luminescence. Currently, the growth of perovskite single crystals mainly employs weakly coordinated solvent systems. For example, the inverse temperature crystallization method using γ-butyrolactone (GBL) as a solvent has become one of the most commonly used processes for growing lead iodine-based perovskite single crystals. This method can achieve rapid growth of high-quality single crystals and has been used to fabricate various high-performance optoelectronic devices.
[0003] However, the growth mechanism of perovskite crystals based on weakly coordinated solvents is not yet fully understood. Because weakly coordinated solvents have limited solubility for lead iodide (PbI₂), complex clusters composed of solvent and precursor readily form in the precursor solution, and these clusters significantly influence the crystal growth process. Although numerous studies have analyzed the solution growth process of perovskite films and emphasized the crucial role of the intermediate phase in crystallization, the significant differences between the precursor solution state and crystallization driving forces in thin films and those in bulk single-crystal growth make these findings difficult to directly apply to single-crystal growth systems. Furthermore, the evaporation and residue behavior of the solvent during crystallization directly affects the final properties of the material: in perovskite films, solvent residue has been shown to impair crystal quality; similarly, solvent residue exists in perovskite single crystals and may adversely affect the long-term stability of the crystal.
[0004] Therefore, existing technologies still lack systematic and in-depth research on the role mechanism of solvents, cluster behavior, and their impact on crystal defects and solvent residues during perovskite single crystal growth. It is necessary to further elucidate the formation, evolution, and role of clusters in weakly coordinated solvent systems during crystallization, thereby guiding the development of more efficient, low-defect, and low-solvent-residue perovskite single crystal growth processes, and further improving crystal quality and the performance of corresponding optoelectronic devices. Summary of the Invention
[0005] The purpose of this invention is to provide an X-ray detector based on a perovskite single crystal grown using a mixed solvent system of 2-methoxyethanol and acetonitrile, and its preparation method. This invention leverages the fact that 2-methoxyethanol is virtually absent within the perovskite single crystal, and that the addition of acetonitrile breaks the internal hydrogen bond network of 2-methoxyethanol, enhancing solute transport. Combined with the ultra-low defect state density of MAPbI3 single crystals grown using a reverse-temperature growth method, the resulting X-ray detector achieves high sensitivity and low dark current at low voltage and exhibits excellent stability during continuous operation exceeding 15 hours.
[0006] The present invention discloses an X-ray detector based on a mixed solvent system of 2-methoxyethanol and acetonitrile for growing perovskite single crystals. It consists of a perovskite single crystal grown in a mixed solvent system of 2-methoxyethanol and acetonitrile, and gold or carbon electrodes located on both sides of the perovskite single crystal. The perovskite single crystal is a MAPbI3 single crystal with a thickness of 1 mm to 5 mm, and the thickness of the gold or carbon electrodes is 20 to 200 nm.
[0007] The present invention discloses a method for preparing an X-ray detector based on a mixed solvent system of 2-methoxyethanol and acetonitrile for growing perovskite single crystals, the steps of which are as follows:
[0008] (1) Preparation of MAPbI3 solution: Mix methylamine iodine and lead iodide in a molar ratio of 1:1 and dissolve them in a mixed solvent of 2-methoxyethanol and acetonitrile in a volume ratio of 4~5:1 to prepare a solution with a methylamine lead iodine concentration of 1.1~1.5M; then mix and stir at room temperature for 3~5h until the perovskite material is completely dissolved to obtain a perovskite MAPbI3 precursor solution;
[0009] (2) Cleaning the reaction vessel and silicon wafer: Place the silicon wafer into the reaction vessel and clean the silicon wafer and the reaction vessel with acetone, ethanol and deionized water in sequence for 15-30 minutes. After cleaning, seal the reaction vessel with tin foil and dry it at 60-75°C.
[0010] (3) Growth of single crystals: The perovskite MAPbI3 precursor solution prepared in step (1) is added to the reaction vessel obtained in step (2). The reaction vessel is sealed with tin foil again and placed on a hot stage at 65~68℃. The temperature is increased at a rate of 0.4~0.6℃ every 3 hours. After 12~15 hours, a perovskite single crystal of appropriate size is grown on the silicon wafer.
[0011] (4) Take out the silicon wafer from step (3) and quickly place it on the hot plate of step (3) for annealing. At the same time, quickly wipe the residual solution on the surface of the perovskite single crystal. After the solution at the interface between the silicon wafer and the perovskite single crystal has completely evaporated, separate the perovskite single crystal from the silicon wafer to obtain a perovskite single crystal with a smooth surface. The perovskite single crystal is a hexagonal structure with a side length of 3mm to 10mm and a thickness of 1mm to 5mm.
[0012] (5) A 20-200 nm thick Au electrode or carbon electrode is deposited on the upper and lower surfaces of the perovskite single crystal obtained in step (4) to obtain an X-ray detector based on the perovskite single crystal grown in a mixed solvent system of 2-methoxyethanol and acetonitrile.
[0013] Compared with existing technologies, the beneficial effects of this invention are reflected in:
[0014] (1) Combining the inverted temperature growth method and the solvent evaporation method, the perovskite single crystal can be rapidly grown by heating the mixed solvent system of 2-methoxyethanol and acetonitrile due to the inverted temperature dissolution of perovskite.
[0015] (2) Taking advantage of the fact that 2-methoxyethanol does not form any residue inside the perovskite single crystal, and the fact that acetonitrile solvent breaks the internal hydrogen bond network of 2-methoxyethanol, the transport capacity of the solute is improved. Furthermore, the single crystal grown on the silicon substrate has a smooth bottom surface, and after rapid drying and annealing, it has a smooth surface. The resulting single crystal has good lattice quality and low defect state density.
[0016] (3) The perovskite single crystal X-ray detector prepared by this method can significantly reduce the dark current and noise of the detector, while obtaining excellent X-ray sensitivity and low dose detection limit. Attached Figure Description
[0017] Figure 1 This is a schematic diagram of the process for preparing MAPbI3 perovskite single crystals in Examples 1-4 and Comparative Examples 1-2 of the present invention;
[0018] Figure 2 These are scanning electron microscope (SEM) images of the internal cross-sections of MAPbI3 perovskite single crystals prepared in Example 1 and Comparative Example 1 of this invention.
[0019] Figure 3 The nuclear magnetic resonance hydrogen spectrum and Fourier transform infrared spectrum are the results of the degree of damage to the hydrogen bond network of 2-methoxyethanol by the solvent used in Example 1 and Comparative Example 2 of this invention.
[0020] Figure 4 The high-resolution X-ray diffraction results and the corresponding rocking curves of the (400) plane of the MAPbI3 perovskite single crystals prepared in Example 1 and Comparative Examples 1-2 of this invention are shown.
[0021] Figure 5 The space charge confinement current curves of the MAPbI3 perovskite single crystals prepared in Example 1 and Comparative Examples 1-2 of this invention are shown.
[0022] Figure 6 The dark current density curves of the X-ray detectors prepared in Example 1 and Comparative Examples 1-2 of this invention are shown.
[0023] Figure 7 The noise curves of the X-ray detectors prepared in Example 1 and Comparative Examples 1-2 of this invention are shown.
[0024] Figure 8 The X-ray response curves of the X-ray detectors prepared in Example 1 and Comparative Examples 1-2 of this invention under an electric field of 1V / mm and different doses are shown.
[0025] Figure 9 The X-ray detector prepared in Example 1 of this invention has a radiation current stability curve after 15 hours of continuous operation.
[0026] Figure 10 The dark current drift curves of the X-ray detectors prepared in Example 1 and Comparative Example 1 of this invention are shown under a continuously applied electric field of 1 V / mm.
[0027] Figure 11 This is a diagram showing the lowest detection limit of the X-ray detector prepared in Example 1 of the present invention under an electric field of 1V / mm. Detailed Implementation
[0028] The following describes in detail, with reference to the accompanying drawings, the specific implementation scheme of the X-ray detector based on the growth of perovskite single crystals in a mixed solvent system of 2-methoxyethanol and acetonitrile according to the present invention.
[0029] Example 1
[0030] (1) Weigh 1033.5 mg (6.5 mmol) of methylamine iodine and 2996.5 mg (6.5 mmol) of lead iodide and add them to a glass bottle. Add 5 mL of a mixed solvent of 2-methoxyethanol (4 mL) and acetonitrile (1 mL) to prepare a methylamine lead iodine solution with a concentration of 1.3 M. Then add a magnetic stir bar. Place the glass bottle on a magnetic stirring table and stir at room temperature for 3 h until the perovskite material is completely dissolved to obtain a perovskite MAPbI3 solution.
[0031] (2) Cleaning the beaker and silicon wafer: Place the silicon wafer covering the bottom of the beaker into a 50mL beaker and clean it with acetone, ethanol and deionized water in sequence for 15min. After ultrasonic cleaning, seal the beaker with tin foil and dry it in a 70℃ drying oven.
[0032] (3) Growth of single crystal: Take 5 mL of the perovskite MAPbI3 precursor solution prepared in step (1) and add it to the clean beaker obtained in step (2), and seal the beaker with tin foil; then place the beaker on a hot plate preheated to 65 degrees Celsius and heat it at a rate of 0.5 degrees Celsius every 3 hours. After 12 hours, a perovskite single crystal of appropriate size will be grown on the silicon wafer.
[0033] (4) Take out the silicon wafer from step (3) and quickly place it on the hot plate of step (3) for annealing. At the same time, quickly wipe the residual solution on the surface of the perovskite single crystal. After the solution at the interface between the silicon wafer and the perovskite single crystal has completely evaporated, separate the perovskite single crystal from the silicon wafer substrate to obtain a perovskite single crystal with a smooth surface. The perovskite single crystal is a hexagonal structure with a side length of 7 mm and a thickness of 3 mm.
[0034] (5) A 40 nm thick Au electrode is deposited on the upper and lower surfaces of the perovskite single crystal obtained in step (4) to obtain an X-ray detector based on the perovskite single crystal.
[0035] Example 2
[0036] (1) Weigh 2067.0 mg (13 mmol) of methylamine iodine and 5993.0 mg (13 mmol) of lead iodide and add them to a glass bottle. Add 10 mL of a mixed solvent of 2-methoxyethanol (8 mL) and acetonitrile (2 mL) to prepare a methylamine lead iodine solution with a concentration of 1.3 M. Then add a magnetic stir bar. Place the glass bottle on a magnetic stirring table and stir at room temperature for 3 h until the perovskite material is completely dissolved to obtain a perovskite MAPbI3 solution.
[0037] (2) Cleaning the beaker and silicon wafer: Place the silicon wafer covering the bottom of the beaker into a 150mL beaker and clean it with acetone, ethanol and deionized water in sequence for 15min. After ultrasonic cleaning, seal the beaker with tin foil and dry it in a 70℃ drying oven.
[0038] (3) Growth of single crystal: Take 10 mL of the perovskite MAPbI3 precursor solution prepared in step (1) and add it to the clean beaker obtained in step (2), and seal the beaker with tin foil; then place the beaker on a hot plate preheated to 65 degrees Celsius and raise the temperature by 0.5°C every 3 hours. After 12 hours, a perovskite single crystal of appropriate size will be grown on the silicon wafer.
[0039] (4) Take out the silicon wafer from step (3) and quickly place it on the hot plate of step (3) for annealing. At the same time, quickly wipe the residual solution on the surface of the perovskite single crystal. After the solution at the interface between the silicon wafer and the perovskite single crystal has completely evaporated, separate the perovskite single crystal from the silicon wafer substrate to obtain a smooth perovskite single crystal surface. The perovskite single crystal is a hexagonal structure with a side length of 8 mm and a thickness of 4 mm.
[0040] (5) A 40 nm thick Au electrode is deposited on the upper and lower surfaces of the perovskite single crystal obtained in step (4) to obtain an X-ray detector based on the perovskite single crystal.
[0041] Example 3
[0042] (1) Weigh 1033.5 mg (6.5 mmol) of methylamine iodine and 2996.5 mg (6.5 mmol) of lead iodide and add them to a glass bottle. Add 5 mL of a mixed solvent of 2-methoxyethanol (4.5 mL) and acetonitrile (0.5 mL) to prepare a 1.3 M methylamine lead iodine solution. Then add a magnetic stir bar. Place the glass bottle on a magnetic stirring table and stir at room temperature for 3 h until the perovskite material is completely dissolved to obtain a MAPbI3 solution.
[0043] (2) Cleaning the beaker and silicon wafer: Place the silicon wafer covering the bottom of the beaker into a 50 mL beaker and clean it with acetone, ethanol and deionized water in sequence for 15 min. After ultrasonic cleaning, seal the beaker with tin foil and dry it in a 70℃ drying oven.
[0044] (3) Growth of single crystal: Take 5 mL of the perovskite MAPbI3 precursor solution prepared in step (1) and add it to the clean beaker obtained in step (2), and seal the beaker with tin foil; then place the beaker on a hot plate preheated to 65 degrees Celsius and raise the temperature by 0.5°C every 3 hours. After 12 hours, a perovskite single crystal of appropriate size will be grown on the silicon wafer.
[0045] (4) Take out the silicon wafer from step (3) and quickly place it on the hot plate of step (3) for annealing. At the same time, quickly wipe the residual solution on the surface of the perovskite single crystal. After the solution at the interface between the silicon wafer and the perovskite single crystal has completely evaporated, separate the perovskite single crystal from the silicon wafer substrate to obtain a perovskite single crystal with a smooth surface. The perovskite single crystal is a hexagonal structure with a side length of 5 mm and a thickness of 2 mm.
[0046] (5) A 40 nm thick Au electrode is deposited on the upper and lower surfaces of the perovskite single crystal obtained in step (4) to obtain an X-ray detector based on the perovskite single crystal.
[0047] Example 4
[0048] (1) Weigh 2067.0 mg (13 mmol) of methylamine iodine and 5993.0 mg (13 mmol) of lead iodide and add them to a glass bottle. Add 10 mL of a mixed solvent of 2-methoxyethanol (4.5 mL) and acetonitrile (0.5 mL) to prepare a 1.3 M methylamine lead iodine solution. Then add a magnetic stir bar. Place the glass bottle on a magnetic stirring table and stir at room temperature for 3 h until the perovskite material is completely dissolved to obtain a MAPbI3 solution.
[0049] (2) Cleaning the beaker and silicon wafer: Place the silicon wafer covering the bottom of the beaker into a 150mL beaker and clean it with acetone, ethanol and deionized water in sequence for 15min. After ultrasonic cleaning, seal the beaker with tin foil and dry it in a 70℃ drying oven.
[0050] (3) Growth of single crystal: Take 10 mL of the perovskite MAPbI3 precursor solution prepared in step (1) and add it to the clean beaker obtained in step (2), and seal the beaker with tin foil; then place the beaker on a hot plate preheated to 65 degrees Celsius and raise the temperature by 0.5°C every 3 hours. After 12 hours, a perovskite single crystal of appropriate size will be grown on the silicon wafer.
[0051] (4) Take out the silicon wafer from step (3) and quickly place it on the hot plate of step (3) for annealing. At the same time, quickly wipe the residual solution on the surface of the perovskite single crystal. After the solution at the interface between the silicon wafer and the perovskite single crystal has completely evaporated, separate the perovskite single crystal from the silicon wafer substrate to obtain a perovskite single crystal with a smooth surface. The perovskite single crystal is a hexagonal structure with a side length of 6 mm and a thickness of 2.5 mm.
[0052] (5) A perovskite single crystal X-ray detector based on perovskite single crystal is prepared by evaporating Au electrodes with a thickness of 40 nm on both sides of the perovskite single crystal obtained in step (4).
[0053] Comparative Example 1
[0054] (1) Weigh 1033.5 mg (6.5 mmol) of methylamine iodine and 2996.5 mg (6.5 mmol) of lead iodide and add them to a glass bottle. Add 5 mL of γ-butyrolactone solvent to prepare a 1.3 M methylamine lead iodine solution. Then add a magnetic stir bar. Place the glass bottle on a magnetic stirring table and stir at room temperature for 8 h until the perovskite material is completely dissolved to obtain a MAPbI3 solution.
[0055] (2) Cleaning the beaker and silicon wafer: Place the silicon wafer covering the bottom of the beaker into a 50mL beaker and clean it with acetone, ethanol and deionized water in sequence for 15min. After ultrasonic cleaning, seal the beaker with tin foil and dry it in a 70℃ drying oven.
[0056] (3) Growth of single crystal: Take 5 mL of the perovskite MAPbI3 precursor solution prepared in step (1) and add it to the clean beaker obtained in step (2), and seal the beaker with tin foil; then place the beaker on a hot plate preheated to 95 degrees Celsius and raise the temperature by 0.5°C every 3 hours. After 12 hours, a perovskite single crystal of appropriate size will be grown on the silicon wafer.
[0057] (4) Take out the silicon wafer from step (3) and quickly place it on the hot plate of step (3) for annealing. At the same time, quickly wipe the residual solution on the surface of the perovskite single crystal. After the solution at the interface between the silicon wafer and the perovskite single crystal has completely evaporated, separate the perovskite single crystal from the silicon wafer substrate to obtain a perovskite single crystal with a smooth surface. The perovskite single crystal is a hexagonal structure with a side length of 3 mm and a thickness of 1.5 mm.
[0058] (5) A 40 nm thick Au electrode is deposited on the upper and lower surfaces of the perovskite single crystal obtained in step (4) to obtain an X-ray detector based on the perovskite single crystal.
[0059] Comparative Example 2
[0060] (1) Weigh 1033.5 mg (6.5 mmol) of methylamine iodine and 2996.5 mg (6.5 mmol) of lead iodide and add them to a glass bottle. Add 5 mL of 2-methoxyethanol solvent to prepare a 1.3 M methylamine lead iodine solution. Then add a magnetic stir bar. Place the glass bottle on a magnetic stirring table and stir at room temperature for 6 h until the perovskite material is completely dissolved to obtain a MAPbI3 solution.
[0061] (2) Cleaning the beaker and silicon wafer: Place the silicon wafer covering the bottom of the beaker into a 50mL beaker and clean it with acetone, ethanol and deionized water in sequence for 15min. After ultrasonic cleaning, seal the beaker with tin foil and dry it in a 70℃ drying oven.
[0062] (3) Growth of single crystal: Take 5 mL of the perovskite MAPbI3 precursor solution prepared in step (1) and add it to the clean beaker obtained in step (2), and seal the beaker with tin foil; then place the beaker on a hot plate preheated to 75 degrees Celsius and raise the temperature by 0.5°C every 3 hours. After 12 hours, a perovskite single crystal of appropriate size will be grown on the silicon wafer.
[0063] (4) The silicon wafer from step (3) is clamped and quickly placed on the hot plate of step (3) for annealing. At the same time, the residual solution on the surface of the perovskite single crystal is quickly wiped dry. After the solution at the interface between the silicon wafer and the perovskite single crystal has completely evaporated, the perovskite single crystal is separated from the silicon wafer substrate to obtain a perovskite single crystal with a smooth surface. The perovskite single crystal is a hexagonal structure with a side length of 4 mm and a thickness of 1.9 mm.
[0064] (5) A 40 nm thick Au electrode is deposited on the upper and lower surfaces of the perovskite single crystal obtained in step (4) to obtain an X-ray detector based on the perovskite single crystal.
[0065] In Examples 1-4, as the growth solution increases, the flux of the solute in space becomes more stable, the growth rate increases slightly, and the maximum size of the obtained MAPbI3 perovskite single crystals increases accordingly.
[0066] Scanning electron microscope images of the interior of the MAPbI3 perovskite single crystals prepared in Example 1 and Comparative Example 2 are shown below. Figure 2 As shown, the single crystal in Example 1 is flat inside with almost no visible grain boundaries, demonstrating good crystal quality. In contrast, the presence of dislocations and needle-like crystals in Comparative Example 1 indicates possible residual sites of solvent inside the single crystal.
[0067] In Examples 1-4, the degree of disruption to the internal hydrogen bond network of 2-methoxyethanol with increasing acetonitrile addition is shown in the 1H NMR and Fourier transform infrared spectra, respectively corresponding to... Figure 3 (1) and Figure 3 (2) When the volume ratio of 2-methoxyethanol to acetonitrile is 8:2, the internal hydrogen bond network of 2-methoxyethanol is most severely damaged, and the solvent has the strongest transport capacity for the solute.
[0068] High-resolution X-ray diffraction results of MAPbI3 perovskite single crystals prepared in Examples 1 and Comparative Examples 1-2, and the rocking curves corresponding to the (200) and (400) planes are shown below. Figure 4 As shown, they correspond to Figure 4 (1) and Figure 4 (2) Compared with Comparative Examples 1-2, the perovskite single crystal in Example 1 exhibited a larger peak ratio and a smaller full width at half maximum (FWHM), demonstrating that it has better lattice quality.
[0069] The space charge confinement current curves of the MAPbI3 perovskite single crystals prepared in Example 1 and Comparative Examples 1-2 are shown below. Figure 5 As shown, they correspond to Figure 5 (1) Figure 5 (2) and Figure 5 (3) Compared with Comparative Examples 1-2, the perovskite single crystal prepared in Example 1 has a lower defect state density;
[0070] The dark current density curves of the MAPbI3 perovskite single-crystal X-ray detectors prepared in Example 1 and Comparative Examples 1-2 are shown below. Figure 6 As shown, compared with Comparative Examples 1-2, the perovskite single-crystal X-ray detector prepared in Example 1 has a lower dark current density.
[0071] The noise curves of the X-ray detectors prepared in Example 1 and Comparative Examples 1-2 are as follows: Figure 7 As shown, the X-ray detector prepared in Example 1 has lower noise compared to Comparative Examples 1-2;
[0072] The X-ray response curves of the X-ray detectors prepared in Example 1 and Comparative Examples 1-2 under a 1V / mm electric field and different doses are shown below. Figure 8 As shown, the X-ray detector prepared in Example 1 has higher sensitivity compared to Comparative Examples 1-2;
[0073] The X-ray current stability curve of the X-ray detector prepared in Example 1 after continuous operation for more than 15 hours is shown below. Figure 9 As shown, the ray response remained essentially unchanged after 15 hours of continuous operation.
[0074] The dark current drift curves of the X-ray detectors prepared in Example 1 and Comparative Example 1 under a continuously applied electric field of 1 V / mm are shown below. Figure 10 As shown, the dark current drift of Example 1 after 15 hours is 5.97 × 10⁻⁶. -9 nA cm -1 s -1 V -1 This is much smaller than the 7.94 × 10⁻⁶ exhibited by the perovskite single-crystal X-ray detector prepared in Comparative Example 1. -3 nA cm -1 s -1 V -1 ;
[0075] The lowest detection limit of the X-ray detector prepared in Example 1 under an electric field of 1V / mm is as follows: Figure 11 As shown, the lower limit of detection is 23.04 nGy s. -1 .
[0076] The above embodiments are merely illustrative examples of the technical solutions of the present invention. The X-ray detector and its fabrication method based on a mixed solvent system of 2-methoxyethanol and acetonitrile for growing perovskite single crystals are not limited to the contents described in the above embodiments. Any modifications, supplements, equivalent substitutions, or improvements made by those skilled in the art within the spirit and principles of this invention should be included within the scope of protection of this invention.
Claims
1. A method for fabricating an X-ray detector based on a mixed solvent system of 2-methoxyethanol and acetonitrile to grow perovskite single crystals, comprising the following steps: (1) Preparation of MAPbI3 solution: Mix methylamine iodine and lead iodide in a molar ratio of 1:1 and dissolve them in a mixed solvent of 2-methoxyethanol and acetonitrile to prepare a solution with a methylamine lead iodine concentration of 1.1~1.5M; then mix and stir at room temperature for 3~5h until the perovskite material is completely dissolved to obtain the perovskite MAPbI3 precursor solution; (2) Cleaning the reaction vessel and silicon wafer: Place the silicon wafer into the reaction vessel and clean the silicon wafer and the reaction vessel with acetone, ethanol and deionized water in sequence for 15-30 minutes. After cleaning, seal the reaction vessel with tin foil and dry it at 60-75°C. (3) Growth of single crystal: The perovskite MAPbI3 precursor solution prepared in step (1) is added to the reaction vessel obtained in step (2). The reaction vessel is sealed with tin foil again and placed on a hot stage at 65~68℃. After 12~15h, a perovskite single crystal of appropriate size is grown on the silicon wafer. (4) Take out the silicon wafer from step (3) and quickly place it on the hot plate of step (3) for annealing. At the same time, quickly wipe the residual solution on the surface of the perovskite single crystal. After the solution at the interface between the silicon wafer and the perovskite single crystal has completely evaporated, separate the perovskite single crystal from the silicon wafer to obtain a perovskite single crystal with a smooth surface. (5) Electrodes are deposited on the upper and lower surfaces of the perovskite single crystal obtained in step (4) to obtain an X-ray detector based on the perovskite single crystal grown in a mixed solvent system of 2-methoxyethanol and acetonitrile.
2. The method for fabricating an X-ray detector based on a mixed solvent system of 2-methoxyethanol and acetonitrile to grow perovskite single crystals as described in claim 1, characterized in that: In step (1), the volume ratio of 2-methoxyethanol to acetonitrile is 4~5:
1.
3. The method for fabricating an X-ray detector based on a mixed solvent system of 2-methoxyethanol and acetonitrile to grow perovskite single crystals as described in claim 1, characterized in that: In step (3), the heating rate of the hot plate is 0.4~0.6℃ every 3 hours.
4. The method for fabricating an X-ray detector based on a mixed solvent system of 2-methoxyethanol and acetonitrile for growing perovskite single crystals as described in claim 1, characterized in that: In step (4), the obtained perovskite single crystal is a hexagonal structure with a side length of 3mm to 10mm and a thickness of 1mm to 5mm.
5. The method for preparing an X-ray detector based on a mixed solvent system of 2-methoxyethanol and acetonitrile to grow perovskite single crystals as described in claim 1, characterized in that: In step (5), an Au electrode or carbon electrode with a thickness of 20~200nm is deposited by vapor deposition.
6. An X-ray detector based on a mixed solvent system of 2-methoxyethanol and acetonitrile for growing perovskite single crystals, characterized in that: It is prepared by the preparation method described in any one of claims 1 to 5.