Antimony-doped cesium terbium chloride microcrystal powder and preparation method thereof

Abstract

The invention relates to the technical field of metal powder material preparation, and particularly discloses antimony-doped cesium terbium chloride microcrystalline powder and a preparation method thereof. The chemical composition of the microcrystalline powder is Cs < 5 > Tb < 1-x > Sb < x > Cl < 8 >. 6H < 2 > O, wherein x is equal to 0.05 to 0.30. The preparation method comprises the following steps: mixing cesium chloride, terbium chloride hexahydrate and antimony trichloride according to a molar ratio of 5: 0.8: x; adding pyridine hydrochloride as a chlorine element supplement, wherein the dosage of the pyridine hydrochloride is that 0.05-0.20 mmol of Py.HCl is used for every 1 mmol of CsCl; adding stearic acid as a process dispersant; and through combined treatment of mechanical ball milling and freeze drying, antimony-doped cesium-terbium-chlorine microcrystal powder with regular morphology and good dispersibility is obtained. The method is simple in process and mild in condition, particle aggregation can be effectively inhibited, the crystallinity and dispersion uniformity of the powder are improved, and the prepared microcrystal powder shows excellent optical performance.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of metal powder material preparation, and particularly relates to a Sb-doped CsTbCl6 microcrystalline powder and a preparation method thereof. BACKGROUND

[0002] Metal halides, as an important class of inorganic functional materials, have diverse compositions and structures, which endow them with rich photoelectric properties. In particular, halides containing rare earth elements have excellent luminescent properties due to their unique electronic structures, and show application potential in optoelectronic devices. The performance realization and optimization of such materials largely depend on efficient and controllable synthesis methods that can produce high-crystallinity, well-dispersed powders.

[0003] However, in the preparation of functional powder materials, how to effectively control the particle size distribution of the powder, reduce hard agglomeration, and obtain regular and consistent particle morphology is a technical difficulty that has long been concerned in the field. For metal halide powders, the existing preparation methods still have many challenges in achieving the above goals. Currently, the synthesis methods of rare earth-doped metal halides mainly include high-temperature solid-phase method, hydrothermal method, and mechanical ball milling method. The high-temperature solid-phase method promotes atomic or ionic diffusion and crystallization by sintering the precursor at high temperature for a long time. The obtained product has high crystallinity, but high temperature easily leads to severe sintering and agglomeration of particles, resulting in uneven composition distribution and poor powder flowability. In addition, this method has high energy consumption and long cycle, which is not conducive to large-scale production. The hydrothermal method promotes crystal growth in a closed high-pressure environment using a solvent medium, and can obtain crystals with regular morphology at a relatively low temperature. However, it has high requirements for equipment, limited production capacity and poor batch repeatability, which is difficult to meet the demand of large-scale production. The mechanical ball milling method relies on mechanical energy to induce solid precursor reaction, and has the advantages of simple operation, mild conditions and easy scaling, but in the traditional ball milling process, the powder is easy to be cold-welded, hygroscopic or agglomerated, which causes the decrease of crystallinity or the introduction of impurities, limiting the improvement of the quality of the final powder product.

[0004] In view of the above problems, researchers such as W. B. Im synthesized rare earth-containing metal halide powders such as Cs3TbCl6 and Rb3TbCl6 by mechanical chemical method. This method directly ball-mills the halide precursor by mechanical force to drive the formation of crystals, showing certain technical advantages. However, this ball-milling process still has deficiencies in controlling the powder morphology and inhibiting particle agglomeration, which restricts the further improvement and application of the performance of the obtained powder material.

[0005] Overall, the existing preparation methods of metal halide powders generally have the problem of insufficient control over the physical properties (such as morphology, particle size, dispersibility) of the powder, while also facing the challenges of energy consumption, efficiency and large-scale production. Therefore, it is necessary to develop a method for preparing Sb 3+The synthesis method of Cs5TbCl8·6H2O doped microcrystalline powder is of great significance for promoting the practical application of this type of functional powder material. Summary of the Invention

[0006] The purpose of this invention is to overcome the problems of severe agglomeration, uneven morphology, and poor crystallinity of metal halide powders in the prior art, and to provide an antimony-doped cesium terbium chloride microcrystalline powder with good dispersibility and high crystallinity, and its preparation method.

[0007] The technical solution of the present invention to achieve the above objectives is as follows:

[0008] This invention first provides an antimony-doped cesium terbium chloride microcrystalline powder with the chemical composition Cs5Tb. 1-x Sb x Cl8·6H2O, where x = 0.05~0.30;

[0009] The powder consists of amorphous particles with a particle size distribution in the range of 0.5-2 μm, and the particles have irregular morphology and local aggregation.

[0010] This invention also provides a method for preparing the above-mentioned antimony-doped cesium terbium chloride microcrystalline powder, comprising the following steps: Step S1: Cesium chloride, terbium chloride hexahydrate, and antimony trichloride are mixed in a molar ratio of 5:0.8:x (x = 0.05~0.30) and placed in a wear-resistant ball mill jar; Step S2: Pyridine hydrochloride is added, with the amount being 0.05~0.20 mmol Py·HCl per 1 mmol CsCl; Step S3: Stearic acid is added, with the amount being 0.01~0.02 g stearic acid per 1 g precursor, to obtain mixture a; Step S4: The above mixture a is ball-milled in a planetary ball mill at 300 rpm for 2 h to obtain mixture b; Step S5: After ball milling, the obtained mixture b is freeze-dried, first cooled at -15 ℃ for 2~8 h; Step S6: Sublimation is carried out under vacuum conditions for 12 hours. h; Step S7: Slowly heat to room temperature to obtain the antimony-doped terbium chloride cesium microcrystalline powder.

[0011] In step S2, the amount of pyridine hydrochloride added is 0.10 mmol per 1 mmol CsCl.

[0012] In step S3, the amount of stearic acid used is 0.015 g per 1 g of precursor.

[0013] In step S5, the freeze-drying time is 4 hours at -15 °C.

[0014] The antimony-doped cesium terbium chloride microcrystalline powder prepared using the technical solution of this invention, through mechanical grinding combined with chlorine supply from pyridine hydrochloride, dispersion by stearic acid, and freeze-drying, effectively improves the crystallinity of the powder, significantly reduces particle agglomeration, and yields microcrystalline powder with irregular morphology. This method is simple to operate, has mild process conditions, and can effectively suppress the formation of secondary phases, providing a feasible technical path for the large-scale preparation of high-quality metal halide powders. Attached Figure Description

[0015] Figure 1 It is the Sb prepared in Example 1 3+ XRD pattern of Cs5TbCl8·6H2O-doped inorganic perovskite material.

[0016] Figure 2 It is the Sb prepared in Example 1 3+ SEM image of Cs5TbCl8·6H2O-doped inorganic perovskite material.

[0017] Figure 3 It is the Sb prepared in Example 1 3+ Elemental surface distribution of Cs5TbCl8·6H2O-doped inorganic perovskite material.

[0018] Figure 4 It is the Sb prepared in Example 1 3+ Image of Cs5TbCl8·6H2O-doped inorganic perovskite material under ultraviolet light. Detailed Implementation

[0019] The present invention will now be described in detail with reference to the accompanying drawings. The present invention provides an antimony-doped cesium terbium chloride microcrystalline powder and a method for preparing the same.

[0020] The preparation process of the antimony-doped cesium terbium chloride microcrystalline powder is as follows: Cesium chloride (CsCl), terbium chloride hexahydrate (TbCl3·6H2O), and antimony trichloride (SbCl3) are mixed in a molar ratio of 5:0.8:x (x = 0.05~0.30) and placed in a wear-resistant ball mill jar. To ensure sufficient chlorine supply in the reaction system and improve powder dispersibility, pyridine hydrochloride (Py·HCl) is further added at a dosage of 0.05~0.20 mmol Py·HCl per 1 mmol CsCl. Stearic acid is also added at a dosage of 0.01~0.02 g stearic acid per 1 g precursor, resulting in mixture a. This mixture is adsorbed onto the particle surface during grinding, thereby preventing agglomeration and improving grinding uniformity. The precursor was ball-milled at 300 rpm for 2 hours in a planetary ball mill (QM-3SP04) to ensure thorough mixing and homogeneous material formation, yielding mixture b. After ball milling, mixture b was freeze-dried. First, it was cooled at -15 °C for 2–8 hours to fully freeze the system; then, it was sublimated under vacuum for 12 hours to remove most of the solvent; finally, it was slowly heated to room temperature to further remove residual solvent and maintain crystal stability, thereby obtaining well-crystallized antimony-doped terbium chloride cesium microcrystalline powder.

[0021] The obtained powder was characterized by scanning electron microscopy (SEM), and the results are as follows: Figure 2 As shown in the figure, the powder sample consists of a large number of relatively uniform particles with amorphous characteristics. The particle size is mainly distributed in the range of 0.5-2 μm, exhibiting a relatively loose micro-aggregate structure. This loose amorphous structure is beneficial for increasing the specific surface area and improving the dispersibility between particles, thereby providing better interfacial contact conditions for subsequent processing or reactions, demonstrating the potential of the method of this invention in the control of powder microstructure.

[0022] Performance tests on the product showed that it emitted yellow fluorescence under ultraviolet light irradiation. Figure 4 XRD analysis Figure 1 The crystal structure of the product was confirmed by the elemental distribution test. Figure 3 This indicates that each element is evenly distributed in the material.

[0023] In the preparation method of the present invention, in order to ensure a sufficient supply of chlorine in the reaction system, the amount of pyridine hydrochloride added is 0.10 mmol per 1 mmol CsCl.

[0024] In the preparation method of the present invention, the amount of stearic acid used is 0.015 g per 1 g of precursor, in order to improve ball milling uniformity and inhibit particle agglomeration.

[0025] In the preparation method of the present invention, the freeze-drying freezing time is preferably 4 h at -15 ℃ to ensure that the system is fully frozen and facilitates subsequent solvent removal.

[0026] Example 1: 5 mmol of cesium chloride (CsCl), 0.8 mmol of terbium chloride hexahydrate (TbCl3·6H2O), and 0.05 mmol of antimony trichloride (SbC3) were accurately weighed and placed in a 25 mL agate ball mill jar. 0.5 mmol of pyridine hydrochloride (Py·HCl) was added to ensure sufficient chlorine supply to the system, and 0.015 g of stearic acid was added to improve powder dispersibility and inhibit particle agglomeration. Then, 25 agate balls with a diameter of 6 mm were added, and the ball mill jar was placed in a planetary ball mill (QM-3SP04) and ball-milled at 300 rpm for 2 hours to ensure thorough mixing and homogenization of the materials. After ball milling, the resulting mixture b was cooled at -15 °C for 4 h to fully freeze the system, followed by freeze-drying. Then, it was sublimated under vacuum for 12 h to remove most of the solvent, and the residual solvent was further removed by slowly heating to room temperature while maintaining crystal structure stability, thus obtaining antimony-doped cesium terbium chloride microcrystalline powder, i.e., Sb. 3+ Doped with Cs5TbCl8·6H2O.

[0027] Characterization of the obtained powder showed that it mainly consisted of amorphous particles in a loosely aggregated state. XRD analysis ( Figure 1 This confirmed its crystal structure, while elemental distribution testing ( Figure 3 This indicates that the elements are evenly distributed in the material.

[0028] Example 2: Based on Example 1, to ensure sufficient chlorine supply and precise control of crystal structure in the ball milling system, pyridine hydrochloride (Py·HCl) was added to the system, with the amounts adjusted to 0.25 mmol, 0.5 mmol, 0.75 mmol, and 1.0 mmol, respectively. The results showed that the powder exhibited the best overall performance when the amount of pyridine hydrochloride was 0.5 mmol.

[0029] Example 3: Based on Example 1, the amount of stearic acid was adjusted to 0.5 wt% (0.005 g), 1.0 wt% (0.010 g), 1.5 wt% (0.015 g), and 2.0 wt% (0.020 g) of the total precursor mass, respectively, to improve powder dispersibility and inhibit particle agglomeration. The results showed that when the amount of stearic acid was 1.5 wt% (0.015 g) of the total precursor mass, the dispersibility and overall performance of the resulting powder were optimal.

[0030] Example 4: Based on Example 1, the freeze-drying cooling time was adjusted to 2 h, 4 h, 6 h, and 8 h, respectively. The results showed that when the cooling time was 4 h, the resulting powder had the best crystal structure and overall performance, which was beneficial for the system to freeze completely and reduce particle agglomeration.

[0031] The above technical solutions only embody the preferred technical solutions of the present invention. Any modifications that may be made by those skilled in the art to certain parts thereof embody the principles of the present invention and fall within the protection scope of the present invention.

Claims

1. An antimony-doped cesium terbium chloride microcrystalline powder, characterized in that, Including the chemical composition Cs5Tb 1-x Sb x Cl8·6H2O, where x = 0.05~0.

30.

2. A method for preparing antimony-doped cesium terbium chloride microcrystalline powder, characterized in that, Includes the following steps: Step S1: Mix cesium chloride, terbium chloride hexahydrate and antimony trichloride in a molar ratio of 5:0.8:x and place the mixture into a wear-resistant ball mill jar; Step S2: Add pyridine hydrochloride at a rate of 0.05–0.20 mmol Py·HCl per 1 mmol CsCl; Step S3: Add stearic acid, using 0.01~0.02 g of stearic acid per 1 g of precursor, to obtain mixture a; Step S4: The above mixture a is ball-milled in a planetary ball mill at a speed of 300 rpm for 2 h to obtain mixture b; Step S5: After ball milling, the resulting mixture b is freeze-dried by cooling at -15 ℃ for 2~8 h. Step S6: Sublime under vacuum for 12 h; Step S7: Slowly heat to room temperature to obtain the antimony-doped cesium terbium chloride microcrystalline powder; The powder consists of amorphous particles with a particle size distribution in the range of 0.5-2 μm, and the particles have irregular morphology and local aggregation.

3. The method according to claim 2, characterized in that, In step S2, the amount of pyridine hydrochloride added is 0.10 mmol per 1 mmol CsCl.

4. The method according to claim 2, characterized in that, In step S3, the amount of stearic acid used is 0.015 g per 1 g of precursor.

5. The method according to claim 2, characterized in that, In step S5, the cooling time for freeze drying is 4 hours at -15 °C.

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