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

Abstract

The application relates to the technical field of metal powder material preparation, and particularly discloses a kind of antimony-doped cesium terbium chloride microcrystalline powder and a preparation method thereof.The chemical composition of the microcrystalline powder is Cs5Tb 1‑ x Sb x Cl8.6H2O, wherein x=0.05-0.30.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 amount of pyridine hydrochloride is 0.05-0.20 mmol per 1 mmol of CsCl; adding stearic acid as a process dispersant; and performing mechanical ball milling and freeze-drying combined treatment to obtain antimony-doped cesium terbium chloride microcrystalline powder with regular morphology and good dispersity.The application has simple process and mild conditions, can effectively inhibit particle agglomeration, improve the crystallinity and dispersion uniformity of the powder, and the prepared microcrystalline powder exhibits 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 the doped Cs5TbCl8·6H2O microcrystalline powder is of great significance to promote the practical application of the functional powder material. SUMMARY

[0006] The present application aims to overcome the problems of the metal halide powder in the prior art, such as serious agglomeration, uneven morphology and poor crystallinity, and to provide a Sb-doped Cs-TbCl microcrystalline powder with good dispersibility and high crystallinity and a preparation method thereof.

[0007] The technical solutions of the present application to achieve the above-mentioned purposes are as follows:

[0008] The present application first provides a Sb-doped Cs-TbCl microcrystalline powder, which has a chemical composition of Cs5Tb 1-x Sb x Cl8·6H2O, wherein x = 0.05~0.30.

[0009] The powder is composed of amorphous particles with a particle size distribution in the range of 0.5-2 μm, and the particle morphology is irregular and locally aggregated.

[0010] The present application also provides a preparation method of the above-mentioned Sb-doped Cs-TbCl microcrystalline powder, comprising the following steps: step S1: mixing cesium chloride, terbium chloride hexahydrate and antimony trichloride according to a molar ratio of 5:0.8:x (x = 0.05~0.30) and placing them in a wear-resistant ball mill jar; step S2: adding pyridine hydrochloride, with an amount of 0.05~0.20 mmol Py·HCl per 1 mmol CsCl; step S3: adding stearic acid, with an amount of 0.01~0.02 g stearic acid per 1 g precursor, to obtain a mixture a; step S4: ball milling the above-mentioned mixture a in a planetary ball mill at a speed of 300 rpm for 2 h to obtain a mixture b; step S5: after ball milling, the obtained mixture b is subjected to freeze-drying treatment, first cooled at -15 ℃ for 2~8 h; step S6: sublimated under vacuum for 12 h; step S7: slowly warmed to room temperature to obtain the Sb-doped Cs-TbCl microcrystalline powder.

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

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

[0013] In the step S5, the freeze-drying freezing time is 4 h at -15 ℃.

[0014] The Sb-doped Cs5TbCl8·6H2O inorganic perovskite material prepared by the technical scheme of the application has the following advantages: the crystallinity of the powder is effectively improved, the particle agglomeration is significantly reduced, and the microcrystalline powder with irregular morphology is obtained through mechanical grinding combined with the supply of chlorine elements of pyridine hydrochloride, the dispersing effect of stearic acid and freeze-drying treatment. The method is simple in operation and mild in process conditions, can effectively inhibit the generation of a side phase, and provides a feasible technical path for the large-scale preparation of high-quality metal halide powder. BRIEF DESCRIPTION OF DRAWINGS

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

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

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

[0018] Figure 4 Sb-doped Cs5TbCl8·6H2O inorganic perovskite material prepared in Example 1 3+ Picture of the Sb-doped Cs5TbCl8·6H2O inorganic perovskite material under ultraviolet light. DETAILED DESCRIPTION

[0019] The application will be described in detail below with reference to the accompanying drawings. The application provides a Sb-doped Cs5TbCl8·6H2O microcrystalline powder and a preparation method thereof.

[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 application, the freezing time for freeze-drying is preferably 4 h at -15 ℃ to ensure that the system is fully frozen, facilitating 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 supply of chlorine elements in 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 a speed of 300 rpm for 2 h to fully mix and homogenize the materials. After ball-milling, the obtained mixture was cooled at -15 ℃ for 4 h to fully freeze the system, and then subjected to freeze-drying treatment. Subsequently, sublimation was carried out under vacuum conditions for 12 h to remove most of the solvent, and further residual solvent was removed by slowly warming to room temperature while maintaining the stability of the crystal structure, thereby obtaining antimony-doped cesium terbium chloride microcrystalline powder, i.e., Sb 3+ doped Cs5TbCl8·6H2O.

[0027] Characterization of the obtained powder showed that it was mainly composed of amorphous particles in a loose aggregated state. XRD analysis ( Figure 1 ) confirmed its crystal structure, and elemental distribution test ( Figure 3 ) showed that each element was uniformly distributed in the material.

[0028] Example 2: On the basis of Example 1, pyridine hydrochloride (Py·HCl) was added to the system to ensure sufficient supply of chlorine elements in the ball-milling system and precise regulation of the crystal structure. The amount of pyridine hydrochloride was adjusted to 0.25 mmol, 0.5 mmol, 0.75 mmol, and 1.0 mmol, respectively. The results showed that when the amount of pyridine hydrochloride was 0.5 mmol, the comprehensive performance of the obtained powder was the best.

[0029] Example 3: On the basis of 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 mass of the precursor, 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 mass of the precursor, the dispersibility and comprehensive performance of the obtained powder were the best.

[0030] Example 4: On the basis of Example 1, the cooling time of the freeze-dried product 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 crystal structure and comprehensive performance of the obtained powder were the best, which was beneficial to the full freezing of the system and the reduction of particle agglomeration.

[0031] The above technical solutions only embody the preferred technical solutions of the present application, and some changes made by the person skilled in the art to some parts thereof also embody the principles of the present application and are within the protection scope of the present application.

Claims

1. A method for preparing a Sb-doped CsTbCl3 microcrystalline powder, characterized in that, The method comprises the following steps: Step S1: mixing cesium chloride, terbium chloride hexahydrate and antimony trichloride according to a molar ratio of 5:0.8:x, and placing the mixture in a wear-resistant ball mill jar; Step S2: adding pyridine hydrochloride, and the amount of pyridine hydrochloride used is 0.05-0.20 mmol of pyridine hydrochloride per 1 mmol of CsCl; Step S3: adding stearic acid, and the amount of stearic acid used is 0.01-0.02 g of stearic acid per 1 g of the precursor, to obtain a mixture a; Step S4: ball milling the mixture a in a planetary ball mill at a rotating speed of 300 rpm for 2 h to obtain a mixture b; Step S5: after the ball milling is completed, the obtained mixture b is subjected to freeze-drying treatment, and first cooled at-15 ℃ for 2-8 h; Step S6: sublimation under vacuum for 12 h; Step S7: slowly warming to room temperature to obtain the antimony-doped cesium terbium chloride microcrystal powder; The powder is composed of amorphous particles with a particle size distribution in the range of 0.5-2 μm, and the particle morphology is irregular and partially aggregated.

2. The method of claim 1, wherein, In the step S2, the amount of pyridine hydrochloride added is 0.10 mmol per 1 mmol of CsCl.

3. The method of claim 1, wherein, In the step S3, the amount of stearic acid used is 0.015 g per 1 g of the precursor.

4. The method of claim 1, wherein, In the step S5, the cooling time of the freeze-drying is 4 h at-15 ℃. In the step S2, the amount of pyridine hydrochloride added is 0.10 mmol per 1 mmol of CsCl. In the step S3, the amount of stearic acid used is 0.015 g per 1 g of the precursor. In the step S5, the cooling time of the freeze-drying is 4 h at-15 ℃.

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