Block beta-phase silver iodide single crystal material and preparation method thereof

Abstract

The invention discloses a bulk beta-phase silver iodide single crystal material and a preparation method thereof, belongs to the technical field of ionic crystal materials, and is characterized in that a bulk beta-AgI single crystal is prepared in a room temperature environment by adopting an anti-solvent method and taking a potassium iodide solution as a good solvent and distilled water as an anti-solvent. According to the bulk beta-phase silver iodide single crystal material and the preparation method thereof, the prepared bulk beta-AgI crystal has good appearance, good thermal performance and high stable temperature, and the method provides new thoughts and conditions for subsequent growth of the crystal and preparation of devices and shows good application prospects.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ion crystal materials, in particular to a bulk beta-phase silver iodide single crystal material and a preparation method thereof. BACKGROUND

[0002] As an important semiconductor material, ion crystal silver halide AgX (X = Cl, Br and I) has been proved to have wide and important applications in the fields of photocatalysis and antibiosis. Among them, silver iodide (AgI) is a bright yellow, odorless, microcrystalline powder at room temperature, with a melting point of 558℃ and a boiling point of 1506℃. AgI crystal has multiple crystal forms, and the common crystal forms include alpha-AgI, beta-AgI and gamma-AgI. At present, the preparation of AgI crystal is less studied. The growth of AgI crystal by the vertical Bridgman method will cause the explosion of iodine vapor due to the volatility of iodine, and it is also difficult to grow bulk AgI crystal by the traditional solution method because of the low solubility of AgI in most solvents.

[0003] The anti-solvent method is a crystal growth technology based on the solubility difference of raw materials in different solvents, and the core is to gradually change the solvent in the small container into a mixed system of the solvent and the anti-solvent by adjusting the diffusion rate of the solvent and the anti-solvent, so as to reduce the solubility of the solute to the supersaturation state, promote the precipitation and growth of the crystal, and the method requires that the solvent has high solubility for the solute and the anti-solvent has low solubility, and the two should have certain mutual solubility. This method has the advantages of simple experimental device, fast crystal growth rate, and easy preparation of bulk single crystal.

[0004] Although this method has the advantages of simple experimental device, fast crystal growth rate, and easy preparation of bulk single crystal, it has feasibility in the synthesis of organic metal halide perovskite single crystal. However, due to the difficulty in precise control of the diffusion process, it is usually difficult to obtain large-size single crystal materials. Therefore, at present, it is still necessary to grow AgI single crystal with good morphology to supplement the preparation method of this kind of material and provide conditions for further research on its potential applications. SUMMARY

[0005] The purpose of the present application is to provide a bulk beta-phase silver iodide single crystal material and a preparation method thereof. The bulk beta-AgI crystal prepared by the method has good external shape and good thermal performance, and has a high stable temperature. The method provides a new idea and condition for the subsequent growth and device preparation of the crystal, and shows good application prospect.

[0006] To achieve the above-mentioned purpose, the present application provides a preparation method of a bulk beta-phase silver iodide single crystal material, comprising the following steps:

[0007] S1, fully dissolving potassium iodide powder in distilled water to obtain a potassium iodide solution;

[0008] S2, adding silver iodide powder into the potassium iodide solution, continuously stirring until a precipitate appears, filtering to obtain a saturated precursor solution;

[0009] S3, placing the saturated precursor solution into a container, using an anti-solvent diffusion method or a dripping method to make the anti-solvent enter the precursor solution, and growing the crystal at a constant temperature, and observing the crystal growth condition;

[0010] S4, after the crystal grows at a constant temperature, taking out the grown bulk AgI single crystal from the solution.

[0011] Preferably, in S1, the concentration of the potassium iodide solution is 2-5 mol / L.

[0012] Preferably, in S3, the anti-solvent is distilled water, and the crystal grows at a constant temperature for 2-7 days.

[0013] Preferably, in S3, when the anti-solvent diffusion method is used, the precursor solution is placed in a small beaker and is moved into a large beaker containing distilled water, the mouth of the large beaker is completely sealed with a preservative film, and then constant temperature heating is performed, and the crystal growth condition is observed.

[0014] Further, the water level of the distilled water in the large beaker is lower than the mouth of the small beaker, and the constant temperature heating temperature is 26-30 DEG C.

[0015] Preferably, in S3, when the anti-solvent dripping method is used, the precursor solution is placed in a jar, distilled water is added into a dripping tube, the needle of the dripping tube is placed above the liquid surface of the precursor solution, the jar is sealed with the mouth of the jar, the dripping device is adjusted to make the distilled water drip into the precursor solution at a constant rate, and the crystal growth condition is observed.

[0016] The application further provides a bulk beta-phase silver iodide single crystal material, which is prepared by using the above preparation method.

[0017] Therefore, the bulk beta-phase silver iodide single crystal material and the preparation method thereof have the following beneficial effects:

[0018] (1) The anti-solvent method is used, the low solubility of silver iodide in distilled water is utilized, the potassium iodide solution is used as a good solvent, and distilled water is used as an anti-solvent, so that the bulk beta-AgI single crystal is prepared in a room temperature environment; the method provides a new idea and condition for the subsequent growth of the crystal and the preparation of a device, and shows a good application prospect.

[0019] (2) The bulk beta-AgI crystal prepared by the application has a good shape and good thermal performance, and has a high stable temperature.

[0020] The technical solutions of the present application are described in further detail below with reference to the accompanying drawings and examples. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a photograph of a β-phase silver iodide single crystal prepared in Example 1 and Example 2 of the present application;

[0022] Figure 2 is an X-ray diffraction pattern of a β-phase silver iodide single crystal prepared in Example 1 of the present application;

[0023] Figure 3 is a scanning electron microscope test pattern of a β-phase silver iodide single crystal prepared in Example 2 of the present application;

[0024] Figure 4 is a simultaneous thermal analysis pattern of a β-phase silver iodide single crystal prepared in Example 2 of the present application. DETAILED DESCRIPTION

[0025] The technical solutions of the present application are described in further detail below with reference to the accompanying drawings and examples.

[0026] Unless otherwise defined, technical or scientific terms used in the present application shall have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs.

[0027] Example 1

[0028] The present application provides a preparation method of a bulk β-phase silver iodide single crystal material, comprising the following steps:

[0029] S1, weigh 66.4 g of potassium iodide powder, add it to 80 mL of distilled water and stir to obtain a potassium iodide solution with a concentration of 5 mol / L;

[0030] S2, add silver iodide powder to the potassium iodide solution, continuously stir at room temperature until a precipitate appears, filter to obtain a saturated precursor solution;

[0031] S3, place the saturated precursor solution in a small beaker and transfer it into a large beaker containing distilled water, the water level in the large beaker is lower than the mouth of the small beaker, completely seal the mouth of the large beaker with a plastic wrap, transfer it to an oil bath of a constant temperature magnetic stirrer, the temperature of the oil bath is 29℃, grow the crystal at a constant temperature for 4 days, and observe the crystal growth;

[0032] S4, after constant temperature heating for 4 days, take out the large beaker containing the small beaker, filter the precursor solution in the small beaker to obtain the grown bulk AgI single crystal.

[0033] Example 2

[0034] The embodiment and the operation of example 1 are the same, the difference is that: in S3, the precursor solution is placed in a jar, distilled water is added in a dropper, the needle of the dropper is placed above the liquid level of the precursor solution, so that the distilled water can be dropped in, the jar is sealed to fix the dropper; the dropping device is adjusted (using the existing structure to set) to make the distilled water drop into the precursor solution at a constant rate, the crystal growth is observed for 4 days; in S4, after the crystal growth for 4 days, the precursor solution in the jar is filtered to obtain the grown bulk AgI single crystal.

[0035] Example 3

[0036] The embodiment and the operation of example 1 are the same, the difference is that: in S3, the crystal is grown at a constant temperature for 7 days; in S4, after the constant temperature heating for 7 days, the large beaker containing the small beaker is taken out as a whole, the precursor solution in the small beaker is filtered to obtain the grown bulk AgI single crystal.

[0037] The actual photos of the bulk AgI single crystals prepared in example 1 and example 2 are shown in Figure 1 , wherein, Figure 1 (a) is the actual photo of the bulk AgI single crystal prepared in example 1, and (b) is the actual photo of the bulk AgI single crystal prepared in example 2, from which Figure 1 (a) and (b) in can be seen that the grown bulk AgI single crystal has a good shape, and the exposed crystal face and edges can be seen, and the good crystal shape is helpful for further testing, research and application of the crystal.

[0038] The bulk AgI single crystal prepared in example 1 is subjected to X-ray diffraction test, and the result is shown in Figure 2 , from which Figure 2 can be seen that the diffraction peak of the bulk AgI single crystal corresponds to the PDF standard card of β-phase silver iodide, and no impurity peak exists, which indicates that the prepared is β-phase silver iodide single crystal.

[0039] The bulk AgI single crystal prepared in example 2 is subjected to scanning electron microscope test, and the result is shown in Figure 3 , wherein, Figure 3 (a) is the SEM graph of the bulk AgI single crystal, (b) is the distribution graph of silver element in the AgI single crystal, and (c) is the distribution graph of iodine element in the AgI single crystal, from which Figure 3 (a), (b) and (c) in can be seen that the prepared AgI single crystal has a relatively flat surface, and the element distribution is uniform, the proportion of the two elements is about 1:1, and no impurity exists.

[0040] The bulk AgI single crystal prepared in example 2 is subjected to simultaneous thermal analysis test, and the result is shown in Figure 4 , from whichFigure 4 It can be seen that the AgI single crystal has good thermal stability below 897℃.

[0041] Therefore, the body block β-AgI crystal prepared by the method has good appearance and good thermal performance, and has a high stable temperature. The method provides a new idea and condition for subsequent growth and device preparation of the crystal, and has a good application prospect.

[0042] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application rather than limiting them, although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that: its still can modify or equivalent replacement of the technical scheme of the present application, and these modifications or equivalent replacements also cannot make the modified technical scheme deviate from the spirit and scope of the technical scheme of the present application.

Claims

1. A method for preparing bulk β-phase silver iodide single crystal material, characterized by: The following steps are involved: S1. Fully dissolving potassium iodide powder in distilled water to obtain a potassium iodide solution; S2. Add silver iodide powder to the potassium iodide solution, stir continuously until precipitation occurs, and filter to obtain a saturated precursor solution; S3, placing the saturated precursor solution in a container, using the antisolvent diffusion method or the dripping method to allow the antisolvent to enter the precursor solution, growing crystals at a constant temperature, and observing the crystal growth; S4. After the constant temperature growth of the crystal is completed, the grown bulk AgI single crystal is taken out from the solution.

2. The method for preparing a bulk β-phase silver iodide single crystal material according to claim 1, characterized in that: In S1, the concentration of the potassium iodide solution is 2 to 5 mol / L.

3. The method for preparing a bulk β-phase silver iodide single crystal material according to claim 1, characterized in that: In S3, the antisolvent is distilled water, and the crystal growth time at constant temperature is 2 to 7 days.

4. The method for preparing a bulk β-phase silver iodide single crystal material according to claim 1, wherein: In S3, when the anti-solvent diffusion method is used, the precursor solution is placed in a small beaker and transferred as a whole into a large beaker filled with distilled water. The mouth of the large beaker is completely sealed with plastic wrap, and then heated at a constant temperature, and the crystal growth is observed.

5. The method for preparing a bulk β-phase silver iodide single crystal material according to claim 4, characterized in that: The water level of distilled water in the large beaker is lower than the mouth of the small beaker, and the constant temperature heating temperature is 26-30℃.

6. The method for preparing a bulk β-phase silver iodide single crystal material according to claim 1, characterized in that: In S3, when the antisolvent drip method is used, the precursor solution is placed in a wide-mouth bottle, distilled water is added to the drip tube, the needle of the drip tube is placed above the liquid surface of the precursor solution, the wide-mouth bottle is sealed with the mouth of the wide-mouth bottle, the drip device is adjusted so that the distilled water drips into the precursor solution at a constant rate, and the crystal growth is observed.

7. A bulk β-phase silver iodide single crystal material, characterized by: The silver iodide single crystal material is prepared by the method for preparing a bulk β-phase silver iodide single crystal material according to any one of claims 1 to 6.

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