Preparation method and application of (4-amp) bibr5 single crystal

Abstract

The application provides a preparation method of (4-AMP)BiBr5 single crystal, which comprises the following steps: providing a hydrobromic acid solution; adding (4-AMP)Br2 and BiBr3 into the hydrobromic acid solution in a molar ratio of 1:1, completely dissolving the (4-AMP)Br2 and BiBr3 at a first predetermined temperature to obtain a crystallization solution; cooling the crystallization solution to a second predetermined temperature at a predetermined cooling rate, so that (4-AMP)BiBr5 single crystals are precipitated from the crystallization solution; and collecting the (4-AMP)BiBr5 single crystals. The (4-AMP)BiBr5 single crystal with high purity and regular structure can be obtained through the simple steps.

Description

Technical Field

[0001] This application relates to the field of X-ray detection, and in particular to the preparation method and application of 4-(aminomethyl)piperidine. Background Technology

[0002] Direct X-ray detection applications require detector materials to possess high atomic numbers, suitable band gaps, high resistivity, and good carrier transport capabilities. High atomic numbers enhance the detector material's absorption of X-rays; suitable band gaps result in lower average ionization energies and lower equilibrium carrier densities; high resistivity reduces dark current during X-ray detection, thereby lowering noise; and good carrier transport performance facilitates the collection of X-ray-excited carriers.

[0003] However, there are very few X-ray direct detection materials that simultaneously meet the above requirements. Conventional existing materials, such as Si, have a low atomic number and can only be used for soft X-ray detection at low energies, while Ge has too low a band gap, resulting in an excessively high equilibrium carrier density and dark current at room temperature, making it practically usable only at low temperatures. α-Se has poor carrier transport performance, resulting in very low sensitivity during X-ray detection.

[0004] (4-AMP)BiBr5 material possesses a high atomic number, suitable band gap, high resistivity, and good carrier transport capability, making it highly suitable for use as a detection material in direct X-ray detection. However, the crystal structure of (4-AMP)BiBr5 is very complex, and existing preparation methods are not easy to prepare high-purity (4-AMP)BiBr5 single crystals quickly and easily, thus limiting the application of (4-AMP)BiBr5 material. Summary of the Invention

[0005] This application provides a method for preparing (4-AMP)BiBr5 single crystals and its application, in order to solve the technical problem that existing preparation methods are difficult to prepare high-purity (4-AMP)BiBr5 single crystals.

[0006] In a first aspect, embodiments of this application provide a method for preparing (4-AMP)BiBr5 single crystals, comprising the following steps:

[0007] Provide hydrobromic acid solution;

[0008] (4-AMP)Br2 and BiBr3 were added to the hydrobromic acid solution in a 1:1 molar ratio, and (4-AMP)Br2 and BiBr3 were completely dissolved at a first predetermined temperature to obtain the solution to be crystallized.

[0009] The solution to be crystallized is cooled to a second predetermined temperature at a predetermined cooling rate so that (4-AMP)BiBr5 single crystals precipitate from the solution to be crystallized.

[0010] Collect (4-AMP)BiBr5 single crystals.

[0011] In some embodiments of this application, the concentration of hydrobromic acid in the hydrobromic acid solution is 45-50 wt%.

[0012] In some embodiments of this application, the concentration of hydrobromic acid in the hydrobromic acid solution is 48 wt%.

[0013] In some embodiments of this application, the first predetermined temperature is 110-120°C.

[0014] In some embodiments of this application, the first predetermined temperature is 120°C.

[0015] In some embodiments of this application, the solution to be crystallized contains Bi 3+ The concentration of ions is 0.3-0.35 mol / L.

[0016] In some embodiments of this application, the solution to be crystallized contains Bi 3+ The concentration of ions is 0.33 mol / L.

[0017] In some embodiments of this application, the predetermined cooling rate is not higher than 1°C / h; and / or,

[0018] The second predetermined temperature is 20-30℃.

[0019] In some embodiments of this application, the second predetermined temperature is 24°C.

[0020] Secondly, embodiments of this application provide a direct X-ray detector, wherein the detection material in the direct X-ray detector is a (4-AMP)BiBr5 single crystal prepared by the above-mentioned preparation method of (4-AMP)BiBr5 single crystal.

[0021] The technical solutions provided in this application have the following advantages compared with the prior art:

[0022] The method for preparing (4-AMP)BiBr5 single crystals provided in this application provides a suitable solvent (i.e., hydrobromic acid) and controls the dissolution temperature (i.e., a first predetermined temperature) to allow (4-AMP)Br2 and BiBr3 to dissolve. The molar ratio of (4-AMP)Br2 to BiBr3 is controlled at 1:1, so that the elemental composition of the solute is completely identical to that of (4-AMP)BiBr5, thereby making it easier for (4-AMP)BiBr5 crystals to precipitate when the solution to be crystallized is precipitated. By controlling the cooling rate and the precipitation temperature (i.e., a second predetermined temperature), the crystals can grow slowly when the solution to be crystallized is precipitated, and finally, high-purity, structurally regular (4-AMP)BiBr5 single crystals are obtained through relatively simple steps. Attached Figure Description

[0023] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0024] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 A schematic flowchart illustrating the preparation method of (4-AMP)BiBr5 single crystal provided in this application embodiment;

[0026] Figure 2 The image shows the XRD test results of (4-AMP)BiBr5 single crystals prepared according to the embodiments of this application.

[0027] Figure 3 The image shows the bandgap test results of (4-AMP)BiBr5 single crystals prepared according to the embodiments of this application;

[0028] Figure 4 The resistivity test results of (4-AMP)BiBr5 single crystals prepared according to the embodiments of this application are shown in the figure.

[0029] Figure 5 The graph shows the mobility lifetime product test results of (4-AMP)BiBr5 single crystals prepared according to the embodiments of this application. Detailed Implementation

[0030] The present application will be described in detail below with reference to specific embodiments and examples, thereby making the advantages and various effects of the present application clearer. Those skilled in the art should understand that these specific embodiments and examples are for illustrative purposes only and are not intended to limit the present application.

[0031] Throughout this specification, unless otherwise specified, the terminology used herein should be understood as having the meaning commonly used in the art. Therefore, unless otherwise defined, 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 application pertains. In the event of any conflict, this specification shall prevail.

[0032] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0033] Existing preparation methods are insufficient to produce high-purity (4-AMP)BiBr5 single crystals.

[0034] The technical solution provided in this application is to solve the above-mentioned technical problems, and the general idea is as follows:

[0035] In a first aspect, embodiments of this application provide a method for preparing (4-AMP)BiBr5 single crystals, comprising the following steps:

[0036] S1: Provide hydrobromic acid solution;

[0037] S2: Add (4-AMP)Br2 and BiBr3 to the hydrobromic acid solution in a molar ratio of 1:1, and allow (4-AMP)Br2 and BiBr3 to dissolve completely at a first predetermined temperature to obtain a solution to be crystallized;

[0038] S3: Cool the solution to be crystallized to a second predetermined temperature at a predetermined cooling rate so that (4-AMP)BiBr5 single crystals precipitate from the solution to be crystallized;

[0039] S4: Collect (4-AMP)BiBr5 single crystals.

[0040] Those skilled in the art will understand that the structural formula of (4-AMP)Br2 is

[0041] The (4-AMP)BiBr5 single crystal described in this application is a known substance, and its single crystal structure is also determined. Specifically, the structure is as follows: six Br atoms form an approximately octahedral structure around a Bi atom, with the six Br atoms occupying the six vertices of the octahedron and one Bi atom occupying the center of the octahedron; multiple octahedral structures are linked together in a chain-like manner to form a one-dimensional structure, with each adjacent octahedral structure sharing one Br atom; 4-AMP is 4-(aminomethyl)piperidine, with protonated 4-AMP ions embedded in the gaps formed by adjacent octahedra, and the amino group and Br are connected by hydrogen bonds.

[0042] It should be noted that hydrogen bonds are generally defined as electrostatic bonds formed between N, O, and F elements and hydrogen. However, in this application, Cl, Br, and I can also form weaker hydrogen bonds with hydrogen. Strictly speaking, these may not be the same as hydrogen bonds in the narrow sense, but they are currently commonly referred to as hydrogen bonds in the field. These weaker hydrogen bonds are particularly important in perovskite structures, and there is a great deal of related research, which will not be elaborated here.

[0043] This application firstly enables (4-AMP)Br2 and BiBr3 to dissolve by providing a suitable solvent (i.e., hydrobromic acid) and controlling the dissolution temperature (i.e., the first predetermined temperature), and controlling the molar ratio of (4-AMP)Br2 and BiBr3 to be 1:1, so that the elemental composition of the solute is completely the same as that of (4-AMP)BiBr5, thereby making it easy for (4-AMP)BiBr5 crystals to precipitate when the solution to be crystallized is precipitated. By controlling the cooling rate and the precipitation temperature (i.e., the second predetermined temperature), the crystals can grow slowly when the solution to be crystallized is precipitated, and finally, high-purity and structurally regular (4-AMP)BiBr5 single crystals are obtained through a relatively simple process.

[0044] In some embodiments of this application, the concentration of hydrobromic acid in the hydrobromic acid solution is 45-50 wt%.

[0045] Those skilled in the art will understand that the beneficial effect of a hydrobromic acid concentration of 45-50% is that this concentration of hydrobromic acid solution can dissolve (4-AMP)Br2 and BiBr3 simultaneously quite well.

[0046] In some embodiments of this application, the concentration of hydrobromic acid in the hydrobromic acid solution is 48 wt%.

[0047] In actual experiments, it was found that the best effect was achieved when the concentration of hydrobromic acid was 48%. In practice, it was found that when (4-AMP)BiBr5 single crystals were prepared with hydrobromic acid at this concentration, the final crystallization was free of phase separation and had high purity.

[0048] In some embodiments of this application, the first predetermined temperature is 110-120°C.

[0049] Those skilled in the art will understand that solution-based crystal growth utilizes the change in solubility of the solute in the solvent. In this system, the solubility of (4-AMP)BiBr5 in hydrobromic acid decreases with decreasing temperature. Therefore, hydrobromic acid can dissolve more (4-AMP)BiBr5 at high temperatures, while at lower temperatures, some of the dissolved (4-AMP)BiBr5 will precipitate out as crystals.

[0050] Those skilled in the art will understand that the boiling point of 45-50 wt% hydrobromic acid is approximately 126 °C; to avoid the volatilization of hydrobromic acid, heating should be carried out under sealed conditions.

[0051] In some embodiments of this application, the first predetermined temperature is 120°C.

[0052] In the actual experiment, it was found that the best effect was achieved when the first predetermined temperature was 120℃. Specifically, at this higher temperature, more (4-AMP)BiBr5 could be dissolved in hydrobromic acid without causing the hydrobromic acid to boil.

[0053] In some embodiments of this application, the solution to be crystallized contains Bi 3+ The concentration of ions is 0.3-0.35 mol / L.

[0054] Those skilled in the art will understand that Bi 3+ The beneficial effect of having an ion concentration of 0.3-0.35 mol / L is that this concentration range matches well with the hydrobromic acid concentration and the first predetermined temperature. Within this concentration range, complete dissolution is possible at the aforementioned hydrobromic acid concentration and the first predetermined temperature. Further increasing the Bi... 3+ If the ion concentration is too high, it is difficult to dissolve completely.

[0055] In some embodiments of this application, the solution to be crystallized contains Bi 3+ The concentration of ions is 0.33 mol / L.

[0056] During the actual experiment, it was found that Bi 3+ The best results were achieved when the ion concentration was 0.33 mol / L. Specifically, in practice, it was found that this concentration could completely dissolve the ions with high repeatability at a hydrobromic acid concentration of 48% and a first predetermined temperature.

[0057] In some embodiments of this application, the predetermined cooling rate is no higher than 1°C / h.

[0058] Those skilled in the art will understand that a lower cooling rate results in slower changes in the system, which is beneficial for growing well-formed single crystals. Actual experiments have shown that well-formed single crystals can be grown when the predetermined cooling rate is no higher than 1°C / h.

[0059] In some embodiments of this application, the second predetermined temperature is 20-30°C.

[0060] Those skilled in the art will understand that the beneficial effect of the second predetermined temperature of 20-30°C is that this temperature range allows for the precipitation of more (4-AMP)BiBr5 single crystals and the equipment is simple, while further reducing the temperature requires the use of refrigeration equipment.

[0061] In some embodiments of this application, the second predetermined temperature is 24°C.

[0062] In the actual experiment, it was found that the second predetermined temperature of 24℃ had the best effect. Specifically, this temperature matches the room temperature. When the single crystal is taken out at this temperature, the residual solution on the surface of the single crystal will not crystallize significantly at room temperature, or dissolve the single crystal that has already precipitated.

[0063] Secondly, based on a general inventive concept, this application also provides a direct-type X-ray detector, wherein the detection material in the direct-type X-ray detector is a (4-AMP)BiBr5 single crystal prepared by the above-described method for preparing (4-AMP)BiBr5 single crystal. The detection material of the direct-type X-ray detector is realized based on the above-described method for preparing (4-AMP)BiBr5 single crystal, and its specific implementation can be referred to the above embodiments; the non-detection material portion of the direct-type X-ray detector can be referred to general embodiments in the art. Since this direct-type X-ray detector adopts some or all of the technical solutions of the above embodiments, it possesses at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be elaborated further here.

[0064] The present application is further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the application. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to national standards. If there is no corresponding national standard, then general international standards, conventional conditions, or conditions recommended by the manufacturer are followed.

[0065] Example

[0066] This embodiment provides a method for preparing (4-AMP)BiBr5 single crystal, including the following steps:

[0067] Sa: Provide a 48% hydrobromic acid solution, add (4-AMP)Br2 and BiBr3 to the solution in a 1:1 molar ratio to obtain a solid-liquid mixture;

[0068] Sb: The solid-liquid mixture is heated to 120°C until (4-AMP)Br2 and BiBr3 are completely dissolved to form Bi. 3+ The concentration of the solution to be crystallized is 0.33 mol / L;

[0069] Sc: The solution to be crystallized is cooled to 24°C at a cooling rate of 1°C / h to precipitate (4-AMP)BiBr5 single crystals in the solution to be crystallized;

[0070] Sd: Filter the solution to be crystallized and collect (4-AMP)BiBr5 single crystals.

[0071] Powder XRD analysis was performed on the collected (4-AMP)BiBr5 single crystals. Please refer to the results for further information. Figure 1 .

[0072] Figure 1 In the powder XRD pattern of the (4-AMP)BiBr5 single crystal sample obtained by growth, the peak positions of each diffraction peak are consistent with the diffraction results of (4-AMP)BiBr5 single crystal in the standard library, and there are no impurity peaks, indicating that the grown (4-AMP)BiBr5 single crystal is of high quality.

[0073] The band gap of (4-AMP)BiBr5 single crystal was characterized by the following method:

[0074] First, the absorption spectrum of (4-AMP)BiBr5 single crystal was obtained using a Shimadzu UV-3600 spectrophotometer with an integrating sphere. The horizontal axis represents wavelength, and the vertical axis represents absorbance. Then, the wavelength on the horizontal axis was converted to the energy of the corresponding photon wavelength, while the vertical axis remained unchanged. A linear fit was then performed, and the intersection of the fitted line and the horizontal axis represents the band gap of the (4-AMP)BiBr5 single crystal.

[0075] Please refer to the characterization results. Figure 2 .

[0076] Depend on Figure 2 The band gap of (4-AMP)BiBr5 single crystal can be calculated to be 2.77 eV, which indicates that the band gap of (4-AMP)BiBr5 single crystal prepared in this embodiment is suitable for use as a detection material for X-ray detection.

[0077] The resistivity of (4-AMP)BiBr5 single crystal was tested. Please refer to the test results. Figure 3 .

[0078] pass Figure 3 The resistivity of (4-AMP)BiBr5 single crystal was calculated to be as high as 4.41 × 10⁻⁶. 9 The high resistivity of Ω·cm helps to suppress dark current.

[0079] The mobility-lifetime product of (4-AMP)BiBr5 single crystals was tested, and the specific test method is as follows:

[0080] Symmetrical electrodes were deposited on the upper and lower surfaces of a (4-AMP)BiBr5 single crystal. Under 450nm LED illumination, current data were recorded when different voltages were applied to both sides of the electrodes, resulting in a curve with voltage on the horizontal axis and current on the vertical axis. The Hecht equation was used for fitting, and the mobility-lifetime product of the (4-AMP)BiBr5 single crystal could be obtained based on the fitting parameters and the crystal thickness.

[0081] Please refer to the test results. Figure 4 .

[0082] pass Figure 4Fitting data revealed that the mobility-lifetime product of (4-AMP)BiBr5 single crystals reached as high as 0.143 cm⁻¹. 2 V -1 This is beneficial for collecting electrons and holes generated by X-ray excitation.

[0083] Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of this application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the referred range.

[0084] In this application, unless otherwise stated, directional terms such as "upper" and "lower" specifically refer to the drawing directions in the accompanying drawings. Furthermore, in the description of this application, the terms "comprising," "including," etc., mean "including but not limited to." Moreover, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. In this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. In this document, "and / or" describes the relationship between related objects, indicating that three relationships can exist; for example, A and / or B can represent: A alone, A and B simultaneously, or B alone. For associations involving three or more related objects described using "and / or", it indicates that any one of the three related objects can exist alone, or at least two of them can exist simultaneously. For example, for A, and / or B, and / or C, it can mean that any one of A, B, and C exists alone, or any two of them exist simultaneously, or all three of them exist simultaneously. In this document, "at least one" means one or more, and "more than one" means two or more. "At least one", "at least one of the following", or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can each be single or multiple.

[0085] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for preparing (4-AMP)BiBr5 single crystal, characterized in that, The preparation method of the (4-AMP)BiBr5 single crystal includes the following steps: Provide hydrobromic acid solution; (4-AMP)Br2 and BiBr3 were added to the hydrobromic acid solution in a 1:1 molar ratio, and (4-AMP)Br2 and BiBr3 were completely dissolved at a first predetermined temperature to obtain the solution to be crystallized. The solution to be crystallized is cooled to a second predetermined temperature at a predetermined cooling rate so that (4-AMP)BiBr5 single crystals precipitate from the solution to be crystallized. Collect (4-AMP)BiBr5 single crystals; The concentration of hydrobromic acid in the hydrobromic acid solution is 45-50 wt%, the first predetermined temperature is 110-120℃, and the Bi in the solution to be crystallized... 3+ The concentration of ions is 0.3-0.35 mol / L, the predetermined cooling rate is no higher than 1℃ / h, and the second predetermined temperature is 20-30℃.

2. The method for preparing (4-AMP)BiBr5 single crystal according to claim 1, characterized in that, The concentration of hydrobromic acid in the hydrobromic acid solution is 48 wt%.

3. The method for preparing (4-AMP)BiBr5 single crystal according to claim 1, characterized in that, The first predetermined temperature is 120°C.

4. The method for preparing (4-AMP)BiBr5 single crystal according to claim 1, characterized in that, Bi 3+ The concentration of ions is 0.33 mol / L.

5. The method for preparing (4-AMP)BiBr5 single crystal according to claim 1, characterized in that, The second predetermined temperature is 24°C.

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