Sulfide perovskite luminescent material and preparation method and application thereof

Abstract

The invention belongs to the technical field of new materials, and relates to a sulfide perovskite luminescent material and a preparation method and application thereof. The preparation method of the sulfide perovskite luminescent material comprises the following steps: 1) mixing LaLuO3 powder and CeO2 powder according to a molar ratio of 1: x, and grinding to obtain a mixture; and 2) in a CS2 gas atmosphere, heating the mixture prepared in the step 1) to 1200-1300 DEG C, and carrying out heat preservation treatment for 2-4 hours to obtain the sulfide perovskite luminescent material (LaLuS3: xCe). The prepared sulfide perovskite luminescent material LaLuS3: xCe has good semiconductor characteristics and luminescent characteristics, has good stability under water environment, high temperature and ultraviolet irradiation, and is expected to be applied to the field of luminescent devices such as light emitting diodes.

Description

Technical Field

[0001] The present invention belongs to the technical field of new materials, and particularly relates to a sulfide perovskite luminescent material, a preparation method thereof, and an application thereof. Background Art

[0002] Light-emitting devices such as light-emitting diodes (LEDs) play an important role in cutting-edge technologies and daily life. The core part of a light-emitting diode is an electroluminescent material. An electroluminescent material needs to have three important basic characteristics: 1) It must have good luminescent properties to achieve high-efficiency luminescence; 2) It must have good conductive properties to achieve carrier transport and recombination, and avoid heat loss caused by non-radiative recombination; 3) It needs to have good stability to adapt to complex and diverse preparation conditions and usage environments. Existing mainstream luminescent materials have certain defects. For example, GaAs has certain toxicity; the stability of organic luminescent materials and halide perovskite luminescent materials is poor; the stability of oxide luminescent materials is good but the conductivity is poor, resulting in low carrier transport efficiency and affecting the luminescence efficiency, and they can only be used as photoluminescent materials. Sulfide perovskite materials refer to compounds that have a perovskite structure and sulfur as the anion element. In this material system, LaLuS3 has high stability, good carrier transport characteristics, and its constituent elements have unique advantages such as environmental friendliness. It is an excellent semiconductor material, but it does not contain luminescent ions and its luminescence performance is average. Therefore, exploring and obtaining new electroluminescent materials has very important scientific significance and application value. Summary of the Invention

[0003] Aiming at the problems and deficiencies existing in the prior art, the purpose of the present invention is to provide a sulfide perovskite luminescent material, a preparation method thereof, and an application thereof.

[0004] In order to achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0005] The first aspect of the present invention provides a preparation method of a sulfide perovskite luminescent material, comprising the following steps:

[0006] S1: Mix LaLuO3 powder and CeO2 powder in a molar ratio of 1:x, and grind to obtain a mixture;

[0007] S2: Under a CS2 gas atmosphere, heat the mixture obtained in step S1 to 1200°C to 1300°C, and keep it warm for 2h to 4h to obtain the sulfide perovskite luminescent material (LaLuS3:xCe).

[0008] According to the above preparation method, preferably, in step S1, the value range of x is 0.01 to 0.05.

[0009] According to the above preparation method, preferably, in step S2, the mixture prepared in step S1 is heated to 1300 °C and heat-treated for 3 h.

[0010] According to the above preparation method, preferably, in step S2, the heating rate is 3 - 10 °C / min. More preferably, the heating rate is 5 °C / min.

[0011] According to the above preparation method, preferably, in step S2, the heat treatment is carried out in a tubular furnace. Before the heat treatment, the mixture prepared in step S1 is first added to the tubular furnace, and the tubular furnace is evacuated. Then, CS2 gas is introduced into the tubular furnace until the pressure reaches 30 Pa - 50 Pa, and then the tubular furnace is heated. More preferably, before the heat treatment, the mixture prepared in step S1 is first added to the tubular furnace, and the tubular furnace is evacuated. Then, CS2 gas is introduced into the tubular furnace until the pressure reaches 30 Pa, and then the tubular furnace is heated.

[0012] According to the above preparation method, preferably, the tubular furnace is evacuated to make the background vacuum lower than 0.1 Pa.

[0013] According to the above preparation method, preferably, the flow rate of the CS2 gas is 30 SCCM.

[0014] According to the above preparation method, preferably, in step S1, the particle size of the mixture is 5 μm - 50 μm.

[0015] In the second aspect of the present invention, a sulfide perovskite luminescent material prepared by using the above preparation method in the first aspect is provided.

[0016] In the third aspect of the present invention, the application of the sulfide perovskite luminescent material described in the second aspect above in luminescent materials is provided. Preferably, the luminescent material is an electroluminescent material.

[0017] In the fourth aspect of the present invention, the application of the sulfide perovskite luminescent material described in the second aspect above in light-emitting devices is provided. When the sulfide perovskite luminescent material of the present invention is applied to a light-emitting device, the sulfide perovskite luminescent material needs to be first prepared into a film, and this film is used for the light-emitting device. Preferably, the light-emitting device includes a light-emitting diode and an alternating current electroluminescent device.

[0018] In the fifth aspect of this patent, a light-emitting film is provided, and the light-emitting film is prepared from the sulfide perovskite luminescent material described in the second aspect above.

[0019] The sixth aspect of this patent provides a method for preparing the above-mentioned luminescent thin film described in the fifth aspect. The preparation method is as follows: pressing the sulfide perovskite luminescent material described in the second aspect to obtain a target, and performing magnetron sputtering deposition or pulsed laser deposition treatment on the target to obtain the luminescent thin film; or preparing the sulfide perovskite luminescent material described in the second aspect into a thin film through molecular beam epitaxy treatment to obtain the luminescent thin film.

[0020] The seventh aspect of this patent provides the application of the above-mentioned luminescent thin film described in the fifth aspect in a light-emitting device. Preferably, the light-emitting device includes a light-emitting diode and an alternating current electroluminescent device.

[0021] Compared with the prior art, the positive and beneficial effects achieved by the present invention are as follows:

[0022] (1) In the present invention, LaLuO3 powder and CeO2 powder are mixed and then heat-preserved in an atmosphere of CS2 gas to obtain a sulfide perovskite luminescent material LaLuS3:xCe. This material contains La element, Lu element and Ce 3+ ions at the same time. Ce 3+ ions have a unique 4f-5d transition electron structure and excellent luminescent properties. Moreover, as lanthanide elements, La element and Lu element can be compatible with Ce 3+ ions of the same lanthanide series and provide a good crystal field environment for them. Therefore, the sulfide perovskite luminescent material LaLuS3:xCe prepared by the present invention not only has the excellent semiconductor characteristics and stability of the sulfide perovskite LaLuS3, but also has excellent luminescent properties. It has two emission peaks at 486 nm and 521 nm, its fluorescence lifetime is 4-9 ns, and its luminous efficiency is high.

[0023] (2) The sulfide perovskite luminescent material LaLuS3:xCe prepared by the present invention is a single phase, does not contain other impurities, and has a particle size in the micron range. Moreover, under ultraviolet light irradiation, in an aqueous environment, in an acidic or alkaline environment, and under the condition of 100 °C high-temperature cycling, its structure will not change, and it has good structural stability.

[0024] (3) After being irradiated with ultraviolet light for 3 days, the spectral pattern and intensity of the sulfide perovskite luminescent material LaLuS3:xCe prepared by the present invention have no obvious change, and it has good ultraviolet light irradiation stability; in addition, after experiencing 9 times of 100 °C high-temperature heating cycles, the fluorescence intensity remains above 80% of the initial value, and it has good heat cycle stability.

[0025] (4) The sulfide perovskite luminescent material LaLuS3:xCe prepared by the present invention has a low resistivity, which conforms to the semiconductor resistance value and is conducive to the transport of carriers.

[0026] (5) The raw materials LaLuO3 and CeO2 required for the preparation method of the present invention are common oxide powders. The sulfur source is CS2, which can be conveniently purchased in the commercial market, and the preparation method is simple to operate. Therefore, it is easy to be popularized and applied on a large scale.

[0027] (6) In summary, the sulfide perovskite luminescent material LaLuS3:xCe prepared by the present invention has good semiconductor characteristics and luminescence characteristics. At the same time, it has good stability under water environment, high temperature, and ultraviolet light irradiation, and is expected to be applied in the field of luminescent devices such as light-emitting diodes. Description of the Drawings

[0028] Figure 1 is the flow chart of the preparation method of the sulfide perovskite luminescent material LaLuS3:xCe of the present invention;

[0029] Figure 2 is the XRD pattern of the LaLuS3:xCe materials prepared in Examples 1-5 and Comparative Example of the present invention;

[0030] Figure 3 is the physical picture of the LaLuS3:xCe materials prepared in Examples 1-5 and Comparative Example of the present invention;

[0031] Figure 4 is the scanning electron microscope image of the LaLuS3:xCe luminescent material prepared in Example 3 of the present invention and the LaLuS3 material prepared in Comparative Example;

[0032] Figure 5 is the fluorescence spectrum of the LaLuS3:xCe luminescent materials prepared in Examples 1-5 of the present invention; wherein, the coordinate is the wavelength (nm), and the ordinate is the fluorescence intensity;

[0033] Figure 6 is the fluorescence lifetime graph of the LaLuS3:xCe luminescent materials prepared in Examples 1-5 of the present invention;

[0034] Figure 7 is the integrating sphere diffuse reflectance absorption spectrum of the LaLuS3:xCe materials prepared in Examples 1-5 and Comparative Example of the present invention;

[0035] Figure 8 is the fluorescence spectrum of the LaLuS3:xCe luminescent material prepared in Example 5 of the present invention after 3 days of ultraviolet light irradiation;

[0036] Figure 9 is the detection result graph of the relative fluorescence intensity of the LaLuS3:xCe luminescent materials prepared in Examples 1-5 of the present invention after 1-9 high-temperature heating cycles;

[0037] Figure 10This is the XRD spectrum of the LaLuS3:xCe luminescent material prepared in Example 5 of the present invention after being irradiated with ultraviolet light, immersed in pure water, immersed in acid solution (PH=1), immersed in alkaline solution (PH=13), and heated at 100 degrees high temperature for 9 times. DETAILED DESCRIPTION

[0038] The technical scheme of the present invention will be clearly and completely described below in conjunction with specific embodiments. The following embodiments are convenient for better understanding of the present invention, but are not intended to limit the present invention. The experimental methods in the following embodiments are conventional methods unless otherwise specified. The test materials used in the following embodiments are purchased from conventional biochemical reagent stores unless otherwise specified. The quantitative tests in the following embodiments are repeated three times, and the results are averaged.

[0039] Embodiment 1:

[0040] A method for preparing a sulfide perovskite luminescent material, such as Figure 1 As shown, the specific steps are:

[0041] S1: mixing LaLuO3 powder and CeO2 powder in a molar ratio of 1:0.01, and grinding them thoroughly to make the LaLuO3 powder and CeO2 powder evenly mixed without obvious agglomeration, to obtain a mixture;

[0042] S2: Add the mixture obtained in step S1 into a tubular furnace, evacuate the tubular furnace to make the background vacuum lower than 0.1Pa, introduce CS2 gas into the tubular furnace until the pressure reaches 30Pa, and the flow rate of CS2 gas is 30SCCM, then heat the tubular furnace to 1300°C at a heating rate of 3-10°C / min, and keep the temperature for 3h. After the insulation is completed, cool to room temperature to obtain the sulfide perovskite light-emitting material LaLuS3:xCe, in which the value of x is 0.01.

[0043] Embodiment 2:

[0044] The content of Example 2 is basically the same as that of Example 1, except that: in step S1, LaLuO3 powder and CeO2 powder are mixed in a molar ratio of 1:0.02; in step S2, the x value of the prepared sulfide perovskite luminescent material LaLuS3:xCe is 0.02.

[0045] Embodiment 3:

[0046] The content of Example 3 is basically the same as that of Example 1, except that: in step S1, LaLuO3 powder and CeO2 powder are mixed in a molar ratio of 1:0.03; in step S2, the x value of the prepared sulfide perovskite luminescent material LaLuS3:xCe is 0.03.

[0047] Embodiment 4:

[0048] The content of Example 4 is basically the same as that of Example 1, and the differences are as follows: in step S1, LaLuO3 powder and CeO2 powder are mixed at a molar ratio of 1:0.04; in step S2, the value of x in the prepared sulfide perovskite luminescent material LaLuS3:xCe is 0.04.

[0049] Example 5:

[0050] The content of Example 5 is basically the same as that of Example 1, and the differences are as follows: in step S1, LaLuO3 powder and CeO2 powder are mixed at a molar ratio of 1:0.05; in step S2, the value of x in the prepared sulfide perovskite luminescent material LaLuS3:xCe is 0.05.

[0051] Comparative example:

[0052] The content of the comparative example is basically the same as that of Example 1, and the differences are as follows: in step S1, LaLuO3 powder and CeO2 powder are mixed at a molar ratio of 1:0 (i.e., without CeO2 powder); in step S2, the value of x in the prepared sulfide perovskite luminescent material LaLuS3:xCe is 0, that is, the prepared sulfide perovskite luminescent material is LaLuS3.

[0053] 1. XRD detection of the sulfide perovskite luminescent material LaLuS3:xCe prepared by the present invention:

[0054] XRD detection was carried out on the LaLuS3:xCe luminescent materials prepared in Examples 1 - 5 and the comparative example of the present invention, and the detection results are as Figure 2 shown.

[0055] It can be Figure 2 seen that the experimental observation peak positions of the LaLuS3:xCe materials prepared in Examples 1 - 5 of the present invention match well with the theoretical simulation positions, indicating that the LaLuS3:xCe materials prepared by the present invention have good crystallinity, are single-phase, and do not contain other impurities.

[0056] In addition, the physical photos of the LaLuS3:xCe powders prepared in Examples 1 - 5 and the comparative example of the present invention are as Figure 3 shown. It can be Figure 3 seen that the LaLuS3:xCe material can be successfully prepared by the preparation method of the present invention, and the LaLuS3:xCe material is a fine powder.

[0057] 3. Scanning electron microscope detection of the sulfide perovskite luminescent material LaLuS3:xCe prepared by the present invention:

[0058] Taking the LaLuS3:xCe luminescent material prepared in Example 3 of the present invention as an example, the LaLuS3:xCe luminescent material prepared by the present invention and the LaLuS3 material prepared in the comparative example were detected by scanning electron microscopy, and the detection results are as follows Figure 4 shown.

[0059] It can be seen from Figure 4 that the particle size of the LaLuS3:xCe luminescent material prepared by the present invention is in the micron range, with a particle size of 5 μm to 50 μm. Its particle size meets the requirements and can be prepared into a target by the method of target pressing. The target can be prepared into a thin film by methods such as magnetron sputtering deposition or pulsed laser deposition. Because, if the particle size of the LaLuS3:xCe luminescent material is too large, it will cause cracks, voids, and gaps to easily appear in the subsequent target pressing; if the particle size of the LaLuS3:xCe luminescent material is small, it will cause powder agglomeration and uneven pressing, and higher pressure is required to achieve the same density.

[0060] 4. Fluorescence performance detection of the sulfide perovskite luminescent material LaLuS3:xCe prepared by the present invention:

[0061] The LaLuS3:xCe luminescent materials prepared in Examples 1 - 5 of the present invention and in the comparative example were detected by fluorescence spectroscopy, and the detection results are as follows Figure 5 shown.

[0062] It can be seen from Figure 5 that the LaLuS3:xCe luminescent materials prepared in Examples 1 - 5 of the present invention have emission peaks at 486 nm and 521 nm. These two emission peaks originate from the transitions of Ce 3+ ions 4f5 / 2 and 4f7 / 2, which conform to the emission characteristics of Ce 3+ ions; among them, since the LaLuS3 material prepared in the comparative example does not contain Ce 3+ , therefore, its fluorescence intensity was not detected. In addition, it can also be seen from Figure 5 that as x takes values from 0.01 to 0.05 and the amount of Ce 3+ increases, the emission intensity of the LaLuS3:xCe luminescent material first increases, reaches a peak when x = 0.04, and then decreases when x = 0.05. This is because a high concentration of Ce 3+ ions leads to "concentration quenching", thereby resulting in a decrease in the fluorescence emission intensity.

[0063] 5. Fluorescence lifetime detection of the sulfide perovskite luminescent material LaLuS3:xCe prepared by the present invention:

[0064] The fluorescence lifetime monitoring of the two emission peaks at 486 nm and 521 nm was carried out on the LaLuS3:xCe luminescent materials prepared in Examples 1-5 and the comparative example of the present invention. The detection results are as follows Figure 6 shown.

[0065] As Figure 6 can be seen, the lifetimes of the two emission peaks of the sulfide perovskite luminescent material LaLuS3:xCe prepared in the present invention at 468 nm and 521 nm are 4-9 ns, which is in line with the emission characteristics of Ce ions.

[0066] 6. Integrating sphere diffuse reflectance absorption spectrum detection of the sulfide perovskite luminescent material LaLuS3:xCe prepared in the present invention:

[0067] The integrating sphere diffuse reflectance absorption spectrum detection was carried out on the LaLuS3:xCe luminescent materials prepared in Examples 1-5 and the comparative example of the present invention. The detection results are as follows Figure 7 shown.

[0068] As Figure 7 can be seen, the absorption edge of the LaLuS3:xCe luminescent material prepared in the present invention is located at about 800 nm, and the corresponding band gap is 1.6 eV, which is in line with the semiconductor characteristics and is beneficial to carrier transport.

[0069] 7. Stability detection of the sulfide perovskite luminescent material LaLuS3:xCe prepared in the present invention:

[0070] (1) Fluorescence stability detection after ultraviolet light irradiation treatment:

[0071] Taking the LaLuS3:xCe luminescent material prepared in Example 5 of the present invention as an example, the fluorescence stability detection after ultraviolet light irradiation was carried out. The specific method is as follows: The LaLuS3:xCe luminescent material prepared in Example 5 of the present invention was irradiated with ultraviolet light for 3 days, and the fluorescence characteristics of the LaLuS3:xCe luminescent material were detected after the ultraviolet light irradiation was completed. The detection results are as follows Figure 8 shown.

[0072] As Figure 8 can be seen, after the LaLuS3:5%Ce luminescent material is irradiated with ultraviolet light for 3 days, the spectral pattern and fluorescence intensity of its fluorescence spectrum do not change significantly; thus it is proved that the LaLuS3:5%Ce luminescent material prepared in the present invention has good ultraviolet light irradiation stability.

[0073] (2) Fluorescence stability detection after high-temperature heating treatment:

[0074] The LaLuS3:xCe luminescent materials prepared in Examples 1 - 5 of the present invention were subjected to high-temperature heating cycle treatment, and then fluorescence stability detection was carried out. The specific method is as follows: First, the fluorescence intensity of the LaLuS3:xCe luminescent material at 30 °C was measured and calibrated as 100%. Then, the temperature was raised to 100 °C to measure its fluorescence intensity, and the percentage of the fluorescence intensity at 100 °C to the fluorescence intensity at 30 °C was calculated as the relative fluorescence intensity, forming a cycle. Furthermore, the temperature was continued to be lowered to 30 °C and then raised to 100 °C as the second cycle. Multiple cycles were carried out in sequence to obtain the high-temperature heating cycle stability. Among them, the fluorescence intensity is the intensity of the fluorescence peak.

[0075] The experimental results are as Figure 9 shown.

[0076] It can be Figure 9 seen that when the LaLuS3:x%Ce luminescent materials prepared in Examples 1 - 5 of the present invention were restored to room temperature after undergoing 1 - 9 high-temperature heating cycles, the fluorescence intensity remained above 80% of the initial value; this shows that the LaLuS3:xCe luminescent materials prepared by the present invention have good heat-resistant cycle stability.

[0077] (3) Structure stability detection:

[0078] Taking the LaLuS3:xCe luminescent material prepared in Example 5 of the present invention as an example, XRD detection was carried out on the LaLuS3:xCe luminescent materials after ultraviolet light irradiation treatment, water immersion treatment, acid solution immersion treatment, alkali solution immersion treatment, and high-temperature cycle heating treatment, respectively, to analyze their structure stability.

[0079] Among them, the specific operation of the ultraviolet light irradiation treatment is: The LaLuS3:xCe luminescent material prepared in Example 5 of the present invention was irradiated with ultraviolet light for 3 days, and after the ultraviolet light irradiation ended, XRD detection was carried out on the LaLuS3:xCe luminescent material.

[0080] The specific operation of the water immersion treatment is: The LaLuS3:xCe luminescent material prepared in Example 5 of the present invention was immersed in pure water for 12 h, and after the immersion ended, XRD detection was carried out on the LaLuS3:xCe luminescent material.

[0081] The specific operation of the acid solution immersion treatment is: The LaLuS3:xCe luminescent material prepared in Example 5 of the present invention was immersed in a hydrochloric acid solution (PH = 1) for 12 h, and after the immersion ended, XRD detection was carried out on the LaLuS3:xCe luminescent material.

[0082] The specific operation of the alkali solution immersion treatment is as follows: Immerse the LaLuS3:xCe luminescent material prepared in Example 5 of the present invention in a sodium hydroxide solution (pH = 13) for 12 h. After the immersion, perform XRD detection on the LaLuS3:xCe luminescent material.

[0083] The specific operation of the high-temperature cyclic heating treatment is as follows: First, measure the fluorescence intensity of the LaLuS3:xCe luminescent material at 30 °C and calibrate it as 100%. Then, heat up to 100 °C and measure its fluorescence intensity. Calculate the percentage of the fluorescence intensity at 100 °C to the fluorescence intensity at 30 °C as the relative fluorescence intensity, forming one cycle. Furthermore, continue to cool down to 30 °C and then heat up to 100 °C as the second cycle. Perform multiple cycles in sequence to obtain the high-temperature heating cycle stability. The fluorescence intensity herein refers to the intensity of the fluorescence peak.

[0084] The detection results are as Figure 10 shown.

[0085] It can be Figure 10 seen that the XRD patterns of the LaLuS3:xCe luminescent material prepared by the present invention after 3 days of ultraviolet light irradiation, 12 hours of pure water immersion, acid solution immersion, alkali solution immersion, or high-temperature cyclic heating show no obvious changes compared with those of the untreated LaLuS3:xCe luminescent material. This indicates that the LaLuS3:xCe luminescent material prepared by the present invention has good structural stability under conditions such as ultraviolet light irradiation, water / acid-base environment, and high-temperature cycle.

[0086] 8. Resistivity detection of the LaLuS3:xCe luminescent material prepared by the present invention:

[0087] In order to perform resistivity detection on the LaLuS3:xCe luminescent materials prepared in Examples 1 - 5 and Comparative Example 1 of the present invention, the LaLuS3:xCe luminescent material powders prepared in Examples 1 - 5 and Comparative Example 1 were pressed into blocks and then subjected to resistivity detection. The detection results are shown in Table 1.

[0088] Table 1 Resistivity detection results of the LaLuS3:xCe luminescent materials prepared in Examples 1 - 5 and Comparative Example 1 of the present invention

[0089]

[0090] As can be seen from Table 1, the resistivity of the LaLuS3:xCe luminescent material prepared by the present invention is stable at 1 - 130 kΩ·cm, which conforms to the semiconductor resistance value. Considering that due to the existence of a large number of voids and grain boundaries, there are technically allowable errors in the resistivity of the bulk obtained by measuring the powder compact, but it can be confirmed that it is often higher than its intrinsic resistivity. Therefore, its intrinsic resistivity will be lower than the above value. This shows that the LaLuS3:xCe material prepared by the preparation method of the present invention has a low resistivity, which is beneficial to the transport of carriers.

[0091] In summary, the sulfide perovskite luminescent material LaLuS3:xCe prepared by the present invention has good semiconductor characteristics and luminescent properties. At the same time, it has good stability under water environment, high temperature, and ultraviolet light irradiation, and is promising to be applied in the field of luminescent devices such as light-emitting diodes.

[0092] Finally, it should be noted that the above embodiments are only preferred embodiments of the present invention, and are not intended to limit the present invention in other forms. Any person skilled in the art may use the above technical content as a reference for modification or transformation. These equivalent embodiments with equivalent changes. However, any simple modifications, equivalent changes, and transformations made to the above embodiments based on the technical concept of the present invention still fall within the protection scope of the claims of the present invention.

Claims

1. A preparation method of a sulfide perovskite luminescent material, characterized in that, It includes the following steps: S1: Mix LaLuO3 powder and CeO2 powder at a molar ratio of 1:x, and grind to obtain a mixture; S2: Under the atmosphere of CS2 gas, heat the mixture obtained in step S1 to 1200 °C - 1300 °C, and keep it for 2 h - 4 h to obtain the sulfide perovskite luminescent material.

2. The preparation method according to claim 1, characterized in that, In step S1, the value range of x is 0.01 - 0.

05.

3. The preparation method according to claim 2, characterized in that, In step S2, the heating rate is 3 - 10 °C / min.

4. The preparation method according to any one of claims 1 to 3, characterized in that, In step S2, the heat preservation treatment is carried out in a tube furnace. Before the heat preservation treatment, first add the mixture prepared in step S1 into the tube furnace, evacuate the tube furnace, then introduce CS2 gas into the tube furnace until the pressure is 30 Pa - 50 Pa, and then heat the tube furnace.

5. The preparation method according to claim 4, characterized in that, In step S1, the particle size of the mixture is 5 μm - 50 μm.

6. A sulfide perovskite luminescent material prepared by using the preparation method according to any one of claims 1 - 5.

7. A light-emitting thin film, characterized in that, The light-emitting thin film is prepared from the sulfide perovskite luminescent material according to claim 6.

8. The method for preparing the light-emitting thin film according to claim 7, characterized in that, The preparation method is as follows: Press the sulfide perovskite luminescent material according to claim 6 to obtain a target, and perform magnetron sputtering deposition or pulsed laser deposition treatment on the target to obtain the light-emitting thin film; or prepare the sulfide perovskite luminescent material according to claim 6 into a thin film by molecular beam epitaxy treatment to obtain the light-emitting thin film.

9. The application of the sulfide perovskite luminescent material according to claim 6 or the light-emitting thin film according to claim 7 in a luminescent material or a light-emitting device.

10. The application according to claim 9, characterized in that, The luminescent material is an electroluminescent material; the light-emitting device includes a light-emitting diode and an alternating current electroluminescent device.

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