Zero-dimensional inorganic rare earth metal halide with ultraviolet or blue light capable of exciting yellow light emission as well as preparation method and application of zero-dimensional inorganic rare earth metal halide

Abstract

The invention discloses a zero-dimensional inorganic rare earth metal halide capable of exciting yellow light to emit light by ultraviolet or blue light as well as a preparation method and application of the zero-dimensional inorganic rare earth metal halide, and belongs to the technical field of photoluminescent materials. The compound is prepared by heating a solution of a cesium-containing compound and a dysprosium-containing compound and evaporating and crystallizing the solution. The compound has a completely isolated [DyCl6] octahedral 0D structure and can be excited in an ultraviolet light-blue light region of 300-500 nm in a broadband mode, the emission peak is located at 500-800 nm, and the main emission band is 572 nm. The preparation process flow of the zero-dimensional inorganic rare earth metal halide capable of being excited by ultraviolet light or blue light is simple to operate, the synthesis time is short, and the preparation method has huge application potential and commercial value.

Description

Technical Field

[0001] This invention belongs to the field of photoluminescent materials technology, specifically relating to a zero-dimensional inorganic rare earth metal halide that can be excited by ultraviolet or blue light to emit yellow light, its preparation method and application. Background Technology

[0002] In the field of photoluminescent materials, inorganic metal halides have become a research hotspot due to their excellent optical properties (such as high fluorescence quantum yield and narrowband emission), and have broad application prospects in LED lighting, displays, anti-counterfeiting, and biomarking. Among them, although mainstream lead-based metal halides have outstanding optical properties, their large-scale commercial application is greatly limited by the toxicity of lead and poor environmental stability. Therefore, the development of lead-free, environmentally friendly inorganic metal halides with excellent luminescent properties has become a core demand of the industry.

[0003] Currently reported lead-free metal halides are mostly based on manganese and copper (such as Cs4SnX6 and Cs4MnX6 (X = Cl, Br, I)). Although these materials solve the lead toxicity problem, their luminescent properties depend on main group or transition metal ions (such as Sn). 2+ Mn 2+ Bi 3+ Sb 3+ The transition of ) has limitations such as narrow excitation bandwidth and limited color purity, making it difficult to meet the requirements of high-end optoelectronic devices for wide excitation and high color purity luminescence.

[0004] Rare earth ions (such as lanthanides) possess unique optical properties, including narrow-band emission, high color purity, and long fluorescence lifetime, due to their 4f-4f or 4f-5d electron transitions, making them ideal luminescent active centers. However, current research on zero-dimensional inorganic metal halides largely focuses on non-rare earth metal ions, with very few reports on the luminescence properties of zero-dimensional inorganic rare earth metal halides of lanthanides. In particular, there is a lack of systems that can be broadbandly excited in the ultraviolet-blue light region (360-460 nm) and directly output yellow light—yellow light luminescent materials are a core component of commercial white LEDs (the mainstream approach is "blue GaN chip + YAG:Ce"). 3+ The performance of yellow phosphor directly determines the color rendering index and luminous efficacy of white LEDs, and its academic and application value is significant.

[0005] Existing yellow fluorescent materials (such as BaNb2O6:Dy) 3+ BaZrSi3O9:Bi 3+ Most are "matrix-doped," meaning they are created by doping rare earth ions (such as Dy) into an oxide / fluoride matrix. 3+This method achieves yellow light emission. However, such materials have inherent drawbacks: on the one hand, the significant difference in ionic radii between the dopant ions and the matrix element can easily lead to lattice defects and reduce material stability; on the other hand, the doping amount needs to be strictly controlled. If the doping amount is too low, the luminescence intensity will be insufficient, and if the doping amount is too high, concentration quenching may occur. Furthermore, the 4f-4f transition of rare earth ions is parity forbidden, resulting in a small absorption cross-section, requiring the use of sensitized ions (such as Ce) to achieve this. 3+ Bi 3+ The excitation band is either enhanced by charge transfer band or has a narrow excitation band (typically <20 nm), which makes it difficult to match with the wide emission spectrum of ultraviolet / blue LED chips, further limiting its application effect.

[0006] In lanthanides, Dy 3+ of 4 F9 / 2→ 6 H 13 The / 2 transition can directly emit yellow light at ~572 nm, making it an ideal active center for yellow light emission. However, Dy... 3+ Two major bottlenecks exist in traditional oxide / fluoride matrices: firstly, low excitation efficiency, requiring sensitization ions; and secondly, narrow excitation band (<20 nm), making them unsuitable for commercial UV / blue LED chips (360-460 nm). Currently, the journal *J THERM ANAL CALORIM* has reported one-dimensional CsDy2Cl7 and zero-dimensional Cs3DyCl6 compounds, in which Dy... 3+ The [DyCl6] octahedral chain / network structure, which shares edges or vertices, results in the excitation spectrum being limited to a narrow band of 350–370 nm.

[0007] From the perspective of preparation technology, existing methods for synthesizing inorganic metal halides (such as solvothermal methods, hot injection methods, and ligand-assisted reprecipitation methods) have obvious limitations that restrict large-scale industrial production: First, they often use reagents with environmental hazards and biotoxicity (such as organic solvents and heavy metal precursors), which does not conform to the concept of green production; second, they rely on high-pressure reaction conditions, resulting in high equipment costs and high operational risks; and third, the preparation process is complex and time-consuming (usually requiring several hours to tens of hours), resulting in low production efficiency and making it difficult to meet the demand for low cost and high capacity in large-scale applications. Summary of the Invention

[0008] In order to overcome the shortcomings of the prior art, the present invention aims to provide a zero-dimensional inorganic rare earth metal halide that can be excited by ultraviolet or blue light to emit yellow light, as well as its preparation method and application, so as to solve the technical problem that the excitation band of inorganic metal halide is difficult to match with the wide emission spectrum of ultraviolet / blue LED chips.

[0009] To achieve the above objectives, the present invention employs the following technical solution: The first aspect of the present invention discloses a zero-dimensional inorganic rare-earth metal halide that can be excited by ultraviolet or blue light, with the chemical formula Cs4DyCl7, having a completely isolated [DyCl6] octahedral structure.

[0010] Preferably, under ultraviolet light excitation, the emission wavelength range of zero-dimensional inorganic rare earth metal halides that can be excited by ultraviolet or blue light is 500~800 nm.

[0011] Preferably, the excitation spectrum of zero-dimensional inorganic rare earth metal halides that can be excited by ultraviolet or blue light covers the range of 300~500 nm.

[0012] Preferably, the zero-dimensional inorganic rare earth metal halide powder that can be excited by ultraviolet or blue light has an interlaced needle-like structure.

[0013] In a second aspect, the present invention discloses a method for preparing the above-mentioned ultraviolet or blue light excitable zero-dimensional inorganic rare earth metal halides, wherein a solution containing cesium compounds and dysprosium compounds is heated to evaporate and crystallize the solution to obtain zero-dimensional inorganic rare earth metal halides. The molar ratio of the cesium-containing compound to the dysprosium-containing compound is (3.6~4.4):1.

[0014] Preferably, the solution containing the cesium compound and the dysprosium compound is a mixture of an aqueous solution of the cesium compound and a hydrochloric acid solution of the dysprosium compound, or a mixture of a hydrochloric acid solution of the cesium compound and an aqueous solution of the dysprosium compound, or an aqueous solution of the cesium compound and the dysprosium compound.

[0015] Preferably, the cesium-containing compound is cesium chloride or cesium carbonate, and the dysprosium-containing compound is dysprosium chloride or dysprosium nitrate.

[0016] Preferably, the heating temperature is 383~423 K.

[0017] Preferably, the heating time is 20~140 min.

[0018] A third aspect of the present invention discloses the application of the above-mentioned ultraviolet or blue light-exciteable zero-dimensional inorganic rare earth metal halides in the field of temperature sensing.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention provides a zero-dimensional inorganic rare-earth metal halide with the chemical formula Cs4DyCl7 that can be excited to emit yellow light under ultraviolet or blue light. It possesses a completely isolated [DyCl6] octahedral structure (a true 0D structure) and combines the advantages of "0D structure + low-phonon halogen environment + high concentration of DyCl6". 3+ "Triple advantages can solve Dy" 3+Overcoming the challenges of narrow excitation and low efficiency, this zero-dimensional inorganic rare-earth metal halide achieves broadband excitation of 300–500 nm and wide emission (primarily yellow) of 500–800 nm. The halide exhibits the following characteristics: 1) It displays yellow luminescence under UV or blue light excitation; 2) Its continuous excitation band of 300–500 nm covers the UV, near-UV, and the entire blue light window, maintaining high absorption efficiency for chips at 365 nm, 385 nm, 405 nm, and 450 nm, and is compatible with existing industrial packaging processes; 3) Its emission wavelength is between 500 and 800 nm, allowing for simultaneous output of multiple spectral bands with a single excitation, completing the visible spectrum without the need to mix multiple phosphors. Therefore, this zero-dimensional inorganic rare-earth metal halide has the potential for application in temperature sensing.

[0020] The present invention provides a method for preparing zero-dimensional inorganic rare-earth metal halides that emit yellow light under ultraviolet or blue light excitation. This method features: 1) no elemental doping; 2) a simple solution evaporation crystallization method with short production time; and 3) rapid dissolution of the Cs and Dy sources in pure water, resulting in molecular / ionic dispersions in both solutions, instantly forming a homogeneous phase and preventing co-precipitation, thus ensuring the stoichiometric ratio of the final compound. This method simplifies the synthesis of ultraviolet or blue light-excited zero-dimensional inorganic rare-earth metal halides with yellow light emission, solving the problem of requiring elemental doping to achieve yellow emission in zero-dimensional inorganic rare-earth metal halides, and possesses broad commercial value. Attached Figure Description

[0021] Figure 1 The X-ray diffraction (XRD) pattern of Cs4DyCl7 obtained in Example 1 of this invention; Figure 2 This is a schematic diagram of the atomic microstructure of Cs4DyCl7, Cs3DyCl6, and CsDy2Cl7 obtained in Example 1 of the present invention; wherein, (a) is Cs3DyCl6, (b) is Cs4DyCl7, and (c) is CsDy2Cl7. Figure 3 The excitation-emission spectrum of Cs4DyCl7 obtained in Example 2 of this invention; Figure 4 This is a scanning electron microscope image of Cs4DyCl7 obtained in Example 3 of the present invention; Figure 5 This is a comparison chart of the temperature sensitivity of Cs4DyCl7 prepared in Example 4 of the present invention; Figure 6 The image shows the XRD pattern of Cs4DyCl7 obtained in Example 6 of this invention. Specific implementation methods To enable those skilled in the art to understand the features and effects of the present invention, the following descriptions and definitions are only general descriptions of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in the event of any conflict, the definitions in this specification shall prevail.

[0022] This invention provides a method for preparing a zero-dimensional inorganic rare earth metal halide that can be excited by ultraviolet or blue light to emit yellow light. The method involves heating a solution containing cesium and dysprosium compounds at a temperature of 383~423 K for 20~140 min to allow the solution to evaporate and crystallize, thereby obtaining the zero-dimensional inorganic rare earth metal halide Cs4DyCl7. The molar ratio of the cesium-containing compound to the dysprosium-containing compound is (3.6~4.4):1; the cesium-containing compound includes, but is not limited to, cesium chloride (CsCl) or cesium carbonate (Cs2CO3), and the dysprosium-containing compound includes, but is not limited to, dysprosium chloride (DyCl3) or dysprosium nitrate (Dy(NO)3·6H2O); the solution of the cesium compound and the dysprosium-containing compound is a solution obtained by mixing an aqueous solution of the cesium compound and a hydrochloric acid solution of the dysprosium-containing compound, or a solution obtained by mixing a hydrochloric acid solution of the cesium compound and an aqueous solution of the dysprosium-containing compound, or an aqueous solution of the cesium compound and the dysprosium-containing compound.

[0023] The present invention will be 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 invention. Furthermore, it should be understood that after reading this description, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0024] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under standard conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications in the art, unless otherwise stated.

[0025] Example 1 The preparation method of zero-dimensional inorganic rare-earth metal halides that emit yellow light when excited by ultraviolet or blue light includes the following specific steps: Step 1: Dissolve 0.6061 g of high-purity (99.9%) CsCl (3.6 mmol) in 3 mL of distilled water, stir to fully dissolve and disperse CsCl evenly to form a transparent CsCl solution; Step 2: Dissolve 0.4565 g of high-purity (99.9%) Dy(NO)3·6H2O (1 mmol) in 1 mL of hydrochloric acid, stir, and let Dy(NO)3·6H2O dissolve and disperse evenly to form a transparent Dy(NO)3·6H2O solution. Step 3: Mix the CsCl solution obtained in Step 1 with the Dy(NO)3·6H2O solution obtained in Step 2, and heat in an oil bath at 423 K for 20 min to allow the solution to evaporate and crystallize, thereby obtaining the zero-dimensional inorganic rare earth metal halide Cs4DyCl7.

[0026] The obtained zero-dimensional inorganic rare-earth metal halide Cs4DyCl7 was scanned using X-ray diffraction, with Cs3DyCl6 and CsDy2Cl7 used as controls. The results are as follows: Figure 1 As shown, since a PDF card for Cs4DyCl7 was unavailable, Cs4YbCl7, composed of Yb (another rare earth element), was chosen as the XRD reference for Cs4DyCl7. Comparison showed that the product obtained in Example 1 exhibited good consistency with the PDF card for Cs4YbCl7. This demonstrates that the target product Cs4DyCl7 was obtained through Example 1. The atomic microstructure is shown below. Figure 2 As shown, the space group of Cs4DyCl7 is R-3m The unit cell parameters are: a = 7.65 Å, b = 7.646 Å, c = 26.29 Å, α = β = 90°, γ = 120°. The space group of Cs3DyCl6 is [insert space group here]. The unit cell parameters are: a = 11.87 Å, b = 11.87 Å, c = 11.87 Å, α = β = γ = 90°. The space group of CsDy2Cl7 is [insert space group here]. Pnma The unit cell parameters include: a=6.99 Å, b=12.67 Å, ​​c=13.53 Å, α=β=γ=90°.

[0027] Example 2 The preparation method of zero-dimensional inorganic rare-earth metal halides that emit yellow light when excited by ultraviolet or blue light includes the following specific steps: Step 1: Dissolve 0.6398 g of high-purity (99.9%) CsCl (3.8 mmol) in 3 mL of distilled water, stir to fully dissolve and disperse CsCl evenly to form a transparent CsCl solution; Step 2: Dissolve 0.4565 g of high-purity (99.9%) Dy(NO)3·6H2O (1 mmol) in 1 mL of hydrochloric acid, stir, and let Dy(NO)3·6H2O dissolve and disperse evenly to form a transparent Dy(NO)3·6H2O solution. Step 3: Mix the CsCl solution obtained in Step 1 with the Dy(NO)3·6H2O solution obtained in Step 2, and heat in an oil bath at 413 K for 50 min to allow the solution to evaporate and crystallize, thereby obtaining the zero-dimensional inorganic rare earth metal halide Cs4DyCl7.

[0028] The excitation and emission spectra of the zero-dimensional inorganic rare-earth metal halide Cs4DyCl7 prepared in Example 2 were measured using a fluorescence spectrophotometer under 365 nm ultraviolet light excitation. The emission wavelength was between 500 and 800 nm, and the sample emitted yellow fluorescence. Its excitation spectrum was also measured, covering the range of 300–500 nm. Figure 3 ).

[0029] Example 3 The preparation method of zero-dimensional inorganic rare-earth metal halides that emit yellow light when excited by ultraviolet or blue light includes the following specific steps: Step 1: Dissolve 0.6734 g of high-purity (99.9%) CsCl (4 mmol) in 3 mL of distilled water, stir to fully dissolve and disperse CsCl evenly to form a transparent CsCl solution; Step 2: Dissolve 0.4565 g of high-purity (99.9%) Dy(NO)3·6H2O (1 mmol) in 1 mL of hydrochloric acid, stir, and let Dy(NO)3·6H2O dissolve and disperse evenly to form a transparent Dy(NO)3·6H2O solution. Step 3: Mix the CsCl solution obtained in Step 1 with the Dy(NO)3·6H2O solution obtained in Step 2, and heat in an oil bath at 403 K for 80 min to evaporate and crystallize the solution, thus obtaining the zero-dimensional inorganic rare earth metal halide Cs4DyCl7.

[0030] The zero-dimensional inorganic rare-earth metal halide Cs4DyCl7 surface was obtained by electron beam scanning using scanning electron microscopy (SEM), and the results are as follows: Figure 4 As shown, the Cs4DyCl7 powder prepared in Example 3 exhibits an interlaced needle-like morphology at a size of 5 μm.

[0031] Example 4 The preparation method of zero-dimensional inorganic rare-earth metal halides that emit yellow light when excited by ultraviolet or blue light includes the following specific steps: Step 1: Dissolve 0.7071 g of high-purity (99.9%) CsCl (4.2 mmol) in 2 mL of distilled water, stir to fully dissolve and disperse CsCl evenly to form a transparent CsCl solution; Step 2: Dissolve 0.4565 g of high-purity (99.9%) Dy(NO)3·6H2O (1 mmol) in 1 mL of hydrochloric acid, stir, and let Dy(NO)3·6H2O dissolve and disperse evenly to form a transparent Dy(NO)3·6H2O solution. Step 3: Mix the CsCl solution obtained in Step 1 with the Dy(NO)3·6H2O solution obtained in Step 2, and heat in an oil bath at 393 K for 110 min to allow the solution to evaporate and crystallize, thereby obtaining the zero-dimensional inorganic rare earth metal halide Cs4DyCl7.

[0032] Using a variable-temperature sample stage and a spectrometer (QE65Pro, purchased from Marine Optical Instruments, Inc., USA), the sample was subjected to variable-temperature testing with an ultraviolet light source at an excitation wavelength of 365 nm. Temperature-dependent photoluminescence spectral data were obtained, and then fitted using the following formula: With absolute sensitivity ( S A ) and relative sensitivity ( S R Calculation formula: and Where T is the temperature, I(T) is the response signal at temperature T, and I(0) is the response signal at the reference temperature, the data results are obtained. Figure 5 As shown in the diagram, the absolute and relative temperature sensitivity of the Cs4DyCl7 powder prepared in Example 4 are calculated. According to the calculation results, the absolute sensitivity reaches a maximum value of 0.09% K. -1 The relative sensitivity reached its maximum value of 0.82% K. -1 .

[0033] Example 5 The preparation method of zero-dimensional inorganic rare-earth metal halides that emit yellow light when excited by ultraviolet or blue light includes the following specific steps: Step 1: Dissolve 0.7407 g of high-purity (99.9%) CsCl (4.4 mmol) in 1 mL of distilled water, stir to fully dissolve and disperse CsCl evenly to form a transparent CsCl solution; Step 2: Dissolve 0.4565 g of high-purity (99.9%) Dy(NO)3·6H2O (1 mmol) in 1 mL of hydrochloric acid, stir, and let Dy(NO)3·6H2O dissolve and disperse evenly to form a transparent Dy(NO)3·6H2O solution. Step 3: Mix the CsCl solution obtained in Step 1 with the Dy(NO)3·6H2O solution obtained in Step 2, and heat in an oil bath at 383 K for 140 min to allow the solution to evaporate and crystallize, thereby obtaining the zero-dimensional inorganic rare earth metal halide Cs4DyCl7.

[0034] Example 6 The preparation method of zero-dimensional inorganic rare-earth metal halides that emit yellow light when excited by ultraviolet or blue light includes the following specific steps: Step 1: Dissolve 0.6061 g of high-purity (99.9%) CsCl (3.6 mmol) and 0.2685 g of high-purity (99.9%) DyCl3 (1 mmol) in 3 mL of distilled water, and stir to ensure that the raw materials are fully dissolved and evenly dispersed. Step 2: Heat the mixed solution in an oil bath at 423 K for 20 min to evaporate and crystallize the solution, obtaining the zero-dimensional inorganic rare earth metal halide Cs4DyCl7.

[0035] The obtained zero-dimensional inorganic rare-earth metal halides were scanned using an X-ray diffractometer, and the results are as follows: Figure 6 As shown, since a PDF card for Cs4DyCl7 was not available, Cs4YbCl7, composed of Yb, another rare earth element, was chosen as the XRD reference for Cs4DyCl7. After comparison, the product obtained in Example 6 showed good consistency with the PDF card for Cs4YbCl7. This demonstrates that the target product Cs4DyCl7 was obtained through Example 6.

[0036] Example 7 The preparation method of zero-dimensional inorganic rare-earth metal halides that emit yellow light when excited by ultraviolet or blue light includes the following specific steps: Step 1: Dissolve 0.7407 g of high-purity (99.9%) CsCl (4.4 mmol) and 0.2685 g of high-purity (99.9%) DyCl3 (1 mmol) in 2 mL of distilled water, and stir to ensure that the raw materials are fully dissolved and evenly dispersed. Step 2: Heat the mixed solution in an oil bath at 383 K for 140 min to evaporate and crystallize the solution, obtaining the zero-dimensional inorganic rare earth metal halide Cs4DyCl7.

[0037] Example 8 The preparation method of zero-dimensional inorganic rare-earth metal halides that emit yellow light when excited by ultraviolet or blue light includes the following specific steps: Step 1: Dissolve 0.6520 g of high-purity (99.9%) Cs2CO3 (2 mmol) in 1 mL of HCl, stir to allow Cs2CO3 to react fully and form a transparent mixed solution. The relevant chemical formula is Cs2CO3 + 2HCl = 2CsCl + H2O + CO2↑. Step 2: Dissolve 0.2685 g of high-purity (99.9%) DyCl3 (1 mmol) in 2 mL of distilled water, and stir to ensure the raw material is fully dissolved and evenly dispersed. A transparent DyCl3 solution is obtained.

[0038] Step 3: Mix the CsCl solution obtained in Step 1 with the DyCl3 solution obtained in Step 2, and heat in an oil bath at 423 K for 20 min to evaporate and crystallize the solution, thus obtaining the zero-dimensional inorganic rare earth metal halide Cs4DyCl7.

[0039] The above describes the preferred experimental scheme for preparing and synthesizing Cs4DyCl7. However, it should be noted that improvements and modifications can be made on the basis of this invention without departing from the principle of this invention, and all such improvements and modifications fall within the scope of protection claimed by this invention.

Claims

1. A zero-dimensional inorganic rare-earth metal halide that can be excited by ultraviolet or blue light, characterized in that, It has the chemical formula Cs4DyCl7 and a completely isolated [DyCl6] octahedral structure.

2. The zero-dimensional inorganic rare-earth metal halide excitable by ultraviolet or blue light according to claim 1, characterized in that, Under ultraviolet light excitation, the emission wavelength range of zero-dimensional inorganic rare earth metal halides that can be excited by ultraviolet or blue light is 500~800 nm.

3. The zero-dimensional inorganic rare-earth metal halide excitable by ultraviolet or blue light according to claim 1, characterized in that, The excitation spectrum of zero-dimensional inorganic rare earth metal halides that can be excited by ultraviolet or blue light covers the range of 300~500 nm.

4. A zero-dimensional inorganic rare-earth metal halide excitable by ultraviolet or blue light according to claim 1, characterized in that, Zero-dimensional inorganic rare-earth metal halide powders that can be excited by ultraviolet or blue light have an interlaced needle-like structure.

5. A method for preparing a zero-dimensional inorganic rare-earth metal halide excitable by ultraviolet or blue light as described in any one of claims 1 to 4, characterized in that, The solution of cesium-containing compounds and dysprosium-containing compounds is heated to evaporate and crystallize, yielding zero-dimensional inorganic rare earth metal halides; The molar ratio of the cesium-containing compound to the dysprosium-containing compound is (3.6~4.4):

1.

6. The method for preparing ultraviolet or blue light-exciteable zero-dimensional inorganic rare earth metal halides according to claim 5, characterized in that, The solution containing the cesium compound and the dysprosium compound is a mixture of an aqueous solution of the cesium compound and a hydrochloric acid solution of the dysprosium compound, or a mixture of a hydrochloric acid solution of the cesium compound and an aqueous solution of the dysprosium compound, or an aqueous solution of the cesium compound and the dysprosium compound.

7. The method for preparing ultraviolet or blue light-exciteable zero-dimensional inorganic rare earth metal halides according to claim 5, characterized in that, The cesium-containing compound is cesium chloride or cesium carbonate, and the dysprosium-containing compound is dysprosium chloride or dysprosium nitrate.

8. The method for preparing ultraviolet or blue light-exciteable zero-dimensional inorganic rare earth metal halides according to claim 5, characterized in that, The heating temperature is 383~423 K.

9. The method for preparing ultraviolet or blue light-exciteable zero-dimensional inorganic rare earth metal halides according to claim 5, characterized in that, Heating time is 20~140 min.

10. The application of the ultraviolet or blue light-exciteable zero-dimensional inorganic rare earth metal halide as described in any one of claims 1 to 4 in the field of temperature sensing.

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