Preparation method of full-inorganic vacancy-ordered double perovskite luminescent material

Abstract

The application discloses a preparation method of a full-inorganic vacancy-ordered double perovskite luminescent material, and relates to the technical field of lead-free perovskite luminescent materials; the preparation method is as follows: raw materials CsCl and MoCl5 are put into a polytetrafluoroethylene lining to be mixed; then, CeCl3 or TeO2 is added, hydrochloric acid is added as a solvent, and stirring is carried out for one hour to fully mix and uniformly distribute the materials; finally, the polytetrafluoroethylene lining is put into a reaction kettle cylinder, and is put into an oven to be reacted; after the reaction is completed, the polytetrafluoroethylene lining is slowly cooled to room temperature in the oven, is cleaned with anhydrous ethanol, and is dried to obtain a lead-free perovskite material; the prepared full-inorganic vacancy-ordered double perovskite luminescent material can emit a broadband near-infrared luminescence with a highest peak of about 990 nm under ultraviolet and blue light excitation, and can be used in near-infrared imaging.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of lead-free perovskite light-emitting materials, in particular to a preparation method of a full-inorganic vacancy-ordered double perovskite light-emitting material. BACKGROUND

[0002] Wideband near-infrared light source (near infrared, NIR: ~700-1700 nm) has the characteristics of being invisible to the human eye, having a large penetration depth in biological tissues, and being non-invasive to the illuminated object, and therefore has wide application prospects in the fields of food safety, security monitoring, medical diagnosis, information processing, optical communication, non-invasive monitoring of human physiological state, etc. For example, it can be used for the preparation of optical amplifiers, which constitute an important part of optical fiber communication and are applied in the fields of industry, medicine and military; near-infrared spectrum can be used for night vision detection and non-destructive imaging; this waveband contains the characteristic absorption peak of solvent molecules, and can be used for high-sensitivity spectral measurement and analysis; near-infrared light has a strong penetration depth for human tissue structure, and can be used for detection of oxygenated hemoglobin saturation in the brain and body; it can be used to construct ultra-wideband, high-gain, and output power adjustable lasers, which are expected to be integrated into the next generation of 5G+6G Internet of Everything networks.

[0003] Therefore, the development of wideband near-infrared light-emitting materials has important academic research value and is the premise and foundation for realizing wide application. Compared with near-infrared region one wideband emission light source, high-efficiency light-emitting materials suitable for near-infrared region two (NIR-Ⅱ: 1000-1700 nm) are extremely scarce, especially those with a spectral characteristic of a half-peak width greater than 200 nm. 3+ , Cr 4+ , Ni 2+ , Bi ion / clusters and Mn 2+ -Mn 2+ ion pairs can achieve near-infrared region two wideband emission with a peak value greater than 1000 nm. However, these material systems generally have problems such as high preparation cost, low luminescent efficiency, poor thermal stability, difficulty in controlling the luminescent peak value, lack of systematic mechanism research, and unknown luminescent mechanism, which seriously affect the practical application of near-infrared region two wideband emission light sources in many fields. According to the current reports on the photoluminescence quantum yield of the full-inorganic vacancy-ordered double perovskite Cs2MoCl6, the photoluminescence quantum yield of the perovskite is at a low level, and therefore there is an urgent need for a method for improving the photoluminescence quantum yield.

[0004] Therefore, in order to solve the above technical problems, the application provides a preparation method of a full-inorganic vacancy-ordered double perovskite light-emitting material. SUMMARY

[0005] The purpose of the present application is to deeply study the method for enhancing near-infrared luminescence of CeCl3 or TeO2 doped Cs2MoCl6 perovskite; by changing the type of the doping element, the symmetry of the Cs2MoCl6 perovskite is reduced, thereby the ultraviolet and blue light absorption is improved, thereby the photoluminescence quantum yield is improved, and by adjusting the concentration of the dopant, under the same excitation condition, the luminescence intensity of the Cs2MoCl6 perovskite is increased.

[0006] In order to achieve the above technical effects, the present application is realized by the following technical scheme: a preparation method of a full-inorganic vacancy-ordered double perovskite luminescent material, characterized in that it comprises the following steps:

[0007] S1, taking CsCl and MoCl5 in a molar ratio of CsCl:MoCl5=2-4:1-2 into a tetrafluoroethylene liner to obtain a mixture A;

[0008] S2, adding CeCl3 or TeO2 to the mixture A to obtain a substrate, and adding hydrochloric acid to the substrate for sufficient stirring for 1-1.5 h to make it uniformly mixed to obtain a mixture B;

[0009] S3, placing the mixture B into an oven at 160-200 DEG C for heat preservation reaction for 11-13 h, then taking out and naturally cooling to room temperature, and then washing with anhydrous ethanol for 2-4 times, and drying to obtain the full-inorganic vacancy-ordered double perovskite luminescent material Cs2MoCl6.

[0010] Further, in S2, the mass percentage of CeCl3 or TeO2 added is 1%-10% of the total mass of CsCl and MoCl5.

[0011] Further, in S2, the concentration of the added hydrochloric acid is 37%, and the amount of the added hydrochloric acid is 10 ml.

[0012] Further, in S3, the reaction condition in the oven is 180 DEG C for 12 h.

[0013] Further, in S3, the drying comprises placing the material into an oven, adjusting the temperature to 70-90 DEG C, and drying for 11-13 h.

[0014] Another purpose of the present application is to provide the application of the full-inorganic vacancy-ordered double perovskite luminescent material, characterized in that the full-inorganic vacancy-ordered double perovskite luminescent material is applied in near-infrared imaging.

[0015] The present application has the following beneficial effects:

[0016] (1) the present application prepares Ce 3+The doped full-inorganic vacancy-ordered double perovskite luminescent material can enhance near-infrared luminescence under ultraviolet excitation, and improve the quantum yield of the substance;

[0017] (2) The Te 4+ The doped full-inorganic vacancy-ordered double perovskite luminescent material can enhance near-infrared luminescence under blue light excitation, and improve the quantum yield of the substance;

[0018] (3) The perovskite matrix Cs2MoCl6 selected by the application has good structural stability and excellent optical performance;

[0019] (4) The Ce 3+ and Te 4+ doped Cs2MoCl6 full-inorganic vacancy-ordered double perovskite can reduce the symmetry of the structure, so that the ultraviolet and blue light absorption is enhanced. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0021] Figure 1 It is a crystal structure diagram of the full-inorganic vacancy-ordered double perovskite luminescent material in the embodiment 13 of the application;

[0022] Figure 2 It is an X-ray diffraction (XRD) data diagram of the full-inorganic vacancy-ordered double perovskite luminescent material in each embodiment of the application;

[0023] Figure 3 It is a scanning electron microscope (SEM) of the doped Ce 3+ full-inorganic vacancy-ordered double perovskite luminescent material in each embodiment of the application.

[0024] Figure 4 It is a scanning electron microscope (SEM) of the doped Te 4+ full-inorganic vacancy-ordered double perovskite luminescent material in each embodiment of the application.

[0025] Figure 5 It is a distribution diagram of the doped Ce 3+ full-inorganic vacancy-ordered double perovskite luminescent material in each embodiment of the application.

[0026] Figure 6 It is a distribution diagram of the doped Te 4+ full-inorganic vacancy-ordered double perovskite luminescent material in each embodiment of the application.

[0027] Figure 7Doped with Ce for the example 3+ Emission spectrum and excitation spectrum of full inorganic vacancy-ordered double perovskite luminescent material

[0028] Figure 8 Doped with Te for the example 4+ Emission spectrum and excitation spectrum of full inorganic vacancy-ordered double perovskite luminescent material

[0029] Figure 9 Doped with Ce for the example 3+ Lead-free double perovskite material produces near-infrared quantum efficiency (PLQY) test under 375 nm excitation.

[0030] Figure 10 Doped with Te for the example 4+ Lead-free double perovskite material produces near-infrared quantum efficiency (PLQY) test under 375 nm excitation. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0032] Embodiment 1

[0033] The mass ratio of CsCl and MoCl5 in the full inorganic vacancy-ordered double perovskite luminescent material prepared in this embodiment is CsCl: MoCl5 = 2: 1, and the mass percentage of CeCl3 added is 1% of the total mass of CsCl and MoCl5. The specific preparation steps are as follows:

[0034] (1) According to the proportion, CsCl and MoCl5 are added to the tetrafluoroethylene liner to obtain a mixture A.

[0035] (2) Then, CeCl3 is added to the mixture A of step (1), hydrochloric acid is added, and the mixture is stirred and mixed uniformly to obtain a mixture B.

[0036] (3) Finally, the mixture B obtained in step (2) is placed in an oven at 180℃ for 12h, and after cooling to room temperature, it is washed with anhydrous ethanol, dried, and the full inorganic vacancy-ordered double perovskite luminescent material is obtained.

[0037] The emission intensity of the full inorganic vacancy-ordered double perovskite luminescent material obtained in this embodiment under 360 nm excitation is shown in FIG. 1. Figure 7

[0038] ​The principle of the present application: Ce 3+ ions and Te 4+ The energy level of the ions can interact with the energy level of Cs2MoCl6, thereby exhibiting good luminescent performance; in addition, Ce 3+ and Te 4+ are introduced into the Cs2MoCl6 octahedral lattice, thereby reducing the symmetry of the structure, improving the crystalline quality, improving the ultraviolet and blue light absorption capacity of Cs2MoCl6, and resulting in a higher photoluminescence quantum yield (PLQY).

[0039] Example 2

[0040] In the all-inorganic vacancy-ordered double perovskite luminescent material prepared in this embodiment, the mass ratio of CsCl to MoCl5 is CsCl: MoCl5 = 2:1, and the mass percentage of CeCl3 added is 2% of the total mass of CsCl and MoCl5. The specific preparation steps are as follows:

[0041] (1) CsCl and MoCl5 were taken in proportion and mixed into a tetrafluoroethylene liner to obtain a mixture A.

[0042] (2) Then, CeCl3 was added to the mixture A of step (1), hydrochloric acid was added, and the mixture was stirred and mixed uniformly to obtain a mixture B.

[0043] (3) Finally, the mixture B obtained in step (2) was placed in an oven at 180℃ for 12h, and after cooling to room temperature, it was washed with anhydrous ethanol, dried, and an all-inorganic vacancy-ordered double perovskite luminescent material was obtained.

[0044] The emission intensity of the all-inorganic vacancy-ordered double perovskite luminescent material obtained in this embodiment under 360nm excitation is shown in FIG. Figure 7 .

[0045] Example 3

[0046] In the all-inorganic vacancy-ordered double perovskite luminescent material prepared in this embodiment, the mass ratio of CsCl to MoCl5 is CsCl: MoCl5 = 2:1, and the mass percentage of CeCl3 added is 4% of the total mass of CsCl and MoCl5. The specific preparation steps are as follows:

[0047] (1) CsCl and MoCl5 were taken in proportion and mixed into a tetrafluoroethylene liner to obtain a mixture A.

[0048] (2) Then, CeCl3 was added to the mixture A of step (1), hydrochloric acid was added, and the mixture was stirred and mixed uniformly to obtain a mixture B.

[0049] (3) Finally, the mixture B obtained in step (2) is placed in an oven and kept at 180°C for 12 hours. After cooling to room temperature, it is washed with anhydrous ethanol and dried to obtain an inorganic vacancy-ordered double perovskite luminescent material.

[0050] The emission intensity of the all-inorganic vacancy-ordered double perovskite luminescent material obtained in this embodiment under 360 nm excitation was measured, and the optimal excitation was found to be 375 nm. Figure 7 As shown in the figure, the XRD comparison shows that the sample basically matches the matrix, indicating that the sample was successfully synthesized. Figure 2 As shown, by Figure 3 Scanning electron microscope and Figure 5 This proves that the doped sample was successfully synthesized. Figure 9 The near-infrared quantum efficiency successfully demonstrated a significant improvement in yield. The data above supports the finding that this is due to the reduction in the structural rigidity, which makes the material more susceptible to absorbing ultraviolet light, thus increasing the quantum yield several times over.

[0051] Example 4

[0052] In this embodiment, the molar ratio of CsCl to MoCl5 in the all-inorganic vacancy-ordered double perovskite luminescent material is CsCl:MoCl5 = 2:1, and the mass percentage of CeCl3 added is 6% of the total mass of CsCl and MoCl5. The specific preparation steps are as follows:

[0053] (1) Take CsCl and MoCl5 according to the proportion and add them to the tetrafluoroethylene liner to mix, so as to obtain mixture A.

[0054] (2) Next, CeCl3 is added to mixture A in step (1), hydrochloric acid is added and the mixture is stirred thoroughly to obtain mixture B.

[0055] (3) Finally, the mixture B obtained in step (2) is placed in an oven and kept at 180°C for 12 hours. After cooling to room temperature, it is washed with anhydrous ethanol and dried to obtain an inorganic vacancy-ordered double perovskite luminescent material.

[0056] The emission intensity of the all-inorganic vacancy-ordered double perovskite luminescent material obtained in this embodiment under 360nm excitation is shown below. Figure 7 As shown.

[0057] Example 5

[0058] In this embodiment, the molar ratio of CsCl to MoCl5 in the all-inorganic vacancy-ordered double perovskite luminescent material is CsCl:MoCl5 = 2:1, and the mass percentage of CeCl3 added is 8% of the total mass of CsCl and MoCl5. The specific preparation steps are as follows:

[0059] (1) According to the proportion, CsCl and MoCl5 are added into the tetrafluoroethylene liner to obtain a mixture A.

[0060] (2) Then, CeCl3 is added into the mixture A of step (1), hydrochloric acid is added, and the mixture is stirred and mixed uniformly to obtain a mixture B.

[0061] (3) Finally, the mixture B obtained in step (2) is placed into an oven at 180°C for 12h, and after cooling to room temperature, the mixture is washed with anhydrous ethanol and dried to obtain the all-inorganic vacancy-ordered double perovskite luminescent material.

[0062] The emission intensity of the all-inorganic vacancy-ordered double perovskite luminescent material obtained in this example under 360nm excitation is shown in FIG. 1. Figure 7

[0063] Example 6

[0064] In the all-inorganic vacancy-ordered double perovskite luminescent material prepared in this example, the mass ratio of CsCl and MoCl5 is CsCl:MoCl5=2:1, and the mass percentage of CeCl3 added is 10% of the total mass of CsCl and MoCl5. The specific preparation steps are as follows:

[0065] (1) According to the proportion, CsCl and MoCl5 are added into the tetrafluoroethylene liner to obtain a mixture A.

[0066] (2) Then, CeCl3 is added into the mixture A of step (1), hydrochloric acid is added, and the mixture is stirred and mixed uniformly to obtain a mixture B.

[0067] (3) Finally, the mixture B obtained in step (2) is placed into an oven at 180°C for 12h, and after cooling to room temperature, the mixture is washed with anhydrous ethanol and dried to obtain the all-inorganic vacancy-ordered double perovskite luminescent material.

[0068] The emission intensity of the all-inorganic vacancy-ordered double perovskite luminescent material obtained in this example under 360nm excitation is shown in FIG. 1. Figure 7

[0069] Example 7

[0070] In the all-inorganic vacancy-ordered double perovskite luminescent material prepared in this example, the mass ratio of CsCl and MoCl5 is CsCl:MoCl5=2:1, and the mass percentage of TeO2 added is 1% of the total mass of CsCl and MoCl5. The specific preparation steps are as follows:

[0071] (1) According to the proportion, CsCl and MoCl5 are added into the tetrafluoroethylene liner to obtain a mixture A. ​​

[0072] (2) Then, TeO2 is added to the mixture A of step (1), hydrochloric acid is added, and the mixture is stirred thoroughly to obtain mixture B.

[0073] (3) Finally, the mixture B obtained in step (2) is placed in an oven at 180°C for 12 hours, and then cooled to room temperature. After that, the mixture is washed with anhydrous ethanol and dried to obtain the all-inorganic vacancy-ordered double perovskite luminescent material.

[0074] The emission intensity of the all-inorganic vacancy-ordered double perovskite luminescent material obtained in this example under 360 nm excitation is shown in FIG. 1. Figure 8

[0075] Example 8

[0076] In the all-inorganic vacancy-ordered double perovskite luminescent material prepared in this example, the mass ratio of CsCl and MoCl5 is CsCl:MoCl5 = 2:1, and the mass percentage of TeO2 added is 2% of the total mass of CsCl and MoCl5. The specific preparation steps are as follows:

[0077] (1) CsCl and MoCl5 are mixed according to the proportion to obtain mixture A.

[0078] (2) Then, TeO2 is added to the mixture A of step (1), hydrochloric acid is added, and the mixture is stirred thoroughly to obtain mixture B.

[0079] (3) Finally, the mixture B obtained in step (2) is placed in an oven at 180°C for 12 hours, and then cooled to room temperature. After that, the mixture is washed with anhydrous ethanol and dried to obtain the all-inorganic vacancy-ordered double perovskite luminescent material.

[0080] The emission intensity of the all-inorganic vacancy-ordered double perovskite luminescent material obtained in this example under 360 nm excitation is shown in FIG. 1. Figure 8

[0081] Example 9

[0082] In the all-inorganic vacancy-ordered double perovskite luminescent material prepared in this example, the mass ratio of CsCl and MoCl5 is CsCl:MoCl5 = 2:1, and the mass percentage of TeO2 added is 4% of the total mass of CsCl and MoCl5. The specific preparation steps are as follows:

[0083] (1) CsCl and MoCl5 are mixed according to the proportion to obtain mixture A.

[0084] (2) Then, TeO2 is added to the mixture A of step (1), hydrochloric acid is added, and the mixture is stirred thoroughly to obtain mixture B.​​

[0085] (3) Finally, the mixture B obtained in step (2) is placed in an oven at 180°C for 12h, after cooling to room temperature, washed with anhydrous ethanol, dried, to obtain a full inorganic vacancy-ordered double perovskite luminescent material.

[0086] The emission intensity of the full inorganic vacancy-ordered double perovskite luminescent material obtained in this example under 360nm excitation is shown in FIG. 1. Figure 8

[0087] Example 10

[0088] In the full inorganic vacancy-ordered double perovskite luminescent material prepared in this example, the mass ratio of CsCl and MoCl5 is CsCl:MoCl5=2:1, and the mass percentage of TeO2 added is 6% of the total mass of CsCl and MoCl5. The specific preparation steps are as follows:

[0089] (1) According to the proportion, CsCl and MoCl5 are added to the tetrafluoroethylene liner and mixed to obtain mixture A.

[0090] (2) Then, TeO2 is added to the mixture A of step (1), hydrochloric acid is added and stirred to obtain mixture B.

[0091] (3) Finally, the mixture B obtained in step (2) is placed in an oven at 180°C for 12h, after cooling to room temperature, washed with anhydrous ethanol, dried, to obtain a full inorganic vacancy-ordered double perovskite luminescent material.

[0092] The emission intensity of the full inorganic vacancy-ordered double perovskite luminescent material obtained in this example under 360nm excitation is shown in FIG. 1. Figure 8 Figure 2 As shown in FIG. 2, by comparing the XRD pattern of the substrate, it is found that after doping TeO2, it basically coincides with the substrate as shown in FIG. 3. Figure 4 Scanning electron microscopy and Figure 6 prove that the doped sample is successfully synthesized, Figure 10 The near-infrared quantum efficiency successfully proves that the yield is improved, and the above data supports that it is due to the reduction of the structure itself, which makes the material more easily absorb blue light, thereby improving the performance.

[0093] Example 11

[0094] In the full inorganic vacancy-ordered double perovskite luminescent material prepared in this example, the mass ratio of CsCl and MoCl5 is CsCl:MoCl5=2:1, and the mass percentage of TeO2 added is 8% of the total mass of CsCl and MoCl5. The specific preparation steps are as follows:​​

[0095] (1) According to the proportion, CsCl and MoCl5 are added to the tetrafluoroethylene liner to obtain mixture A.

[0096] (2) Then, TeO2 is added to the mixture A of step (1), hydrochloric acid is added and stirred to obtain mixture B.

[0097] (3) Finally, the mixture B obtained in step (2) is placed in an oven at 180°C for 12h, and after cooling to room temperature, it is washed with anhydrous ethanol and dried to obtain the all-inorganic vacancy-ordered double perovskite luminescent material.

[0098] The emission intensity of the all-inorganic vacancy-ordered double perovskite luminescent material obtained in this example under 360nm excitation is shown in FIG. 1. Figure 8

[0099] Example 12

[0100] In the all-inorganic vacancy-ordered double perovskite luminescent material prepared in this example, the mass ratio of CsCl and MoCl5 is CsCl: MoCl5 = 2:1, and the mass percentage of TeO2 added is 10% of the total mass of CsCl and MoCl5. The specific preparation steps are as follows:

[0101] (1) According to the proportion, CsCl and MoCl5 are added to the tetrafluoroethylene liner to obtain mixture A.

[0102] (2) Then, TeO2 is added to the mixture A of step (1), hydrochloric acid is added and stirred to obtain mixture B.

[0103] (3) Finally, the mixture B obtained in step (2) is placed in an oven at 180°C for 12h, and after cooling to room temperature, it is washed with anhydrous ethanol and dried to obtain the all-inorganic vacancy-ordered double perovskite luminescent material.

[0104] The emission intensity of the all-inorganic vacancy-ordered double perovskite luminescent material obtained in this example under 360nm excitation is shown in FIG. 1. Figure 8

[0105] Example 13

[0106] As a comparison, the difference between this example and Example 1 is that no CeCl3 or TeO2 is doped, and the specific preparation steps are as follows:

[0107] (1) According to the proportion, CsCl and ZrCl4 are added to the tetrafluoroethylene liner to obtain mixture A.

[0108] ​​(2) Then, hydrochloric acid is added to the mixture A obtained in step (1) and stirred sufficiently to obtain a mixture B.

[0109] (3) Finally, the mixture B obtained in step (2) is put into an oven and kept at 180°C for 12 hours. After cooling to room temperature, the mixture is washed with anhydrous ethanol, dried, and an all-inorganic vacancy-ordered double perovskite luminescent material is obtained.

[0110] The crystal structure of the all-inorganic vacancy-ordered double perovskite luminescent material obtained in this example is shown in FIG. 1, and the XRD is basically consistent with the standard card, indicating that the substrate is successfully synthesized. According to the known literature, the quantum yield of the material is only about 10%, which has a great space for improvement. Figure 1

[0111] The preferred embodiments of the present application disclosed above are only used to help explain the present application. The preferred embodiments do not describe all the details, nor limit the present application to the specific embodiments described. Obviously, many modifications and variations can be made according to the content of the present application. The present application is selected to describe these embodiments in detail in order to better explain the principles of the present application, so that those skilled in the art can well understand and use the present application. The present application is limited only by the claims and their full scope and equivalents.​

Claims

1. A method for preparing an all-inorganic vacancy-ordered double perovskite luminescent material, characterized in that, Includes the following steps: S1. Take CsCl and MoCl5 in a molar ratio of CsCl:MoCl5 = 2~4:1~2 and add them to the tetrafluoroethylene liner to mix, to obtain mixture A; S2. Add CeCl3 to mixture A to obtain the substrate. Add hydrochloric acid to the substrate and stir thoroughly for 1 to 1.5 hours to make it uniformly mixed to obtain mixture B. S3. Place mixture B in an oven at 160~200℃ and keep it at that temperature for 11~13 hours. Then take it out and let it cool naturally to room temperature. Wash it 2~4 times with anhydrous ethanol and dry it to obtain the all-inorganic vacancy-ordered double perovskite luminescent material Cs2MoCl6. In S2, the mass percentage of CeCl3 added is 1% to 10% of the total mass of CsCl and MoCl5.

2. The preparation method of the all-inorganic vacancy-ordered double perovskite luminescent material according to claim 1, characterized in that, In S2, the concentration of hydrochloric acid added is 37%, and the amount of hydrochloric acid added is 10 ml.

3. The method for preparing an all-inorganic vacancy-ordered double perovskite luminescent material according to claim 1, characterized in that, In S3, the reaction conditions in the oven are 180℃ for 12 hours.

4. The preparation method of an all-inorganic vacancy-ordered double perovskite luminescent material according to claim 1, characterized in that, In S3, drying includes placing the material in an oven, adjusting the temperature to 70~90℃, and drying for 11~13 hours.

5. The application of the all-inorganic vacancy-ordered double perovskite luminescent material prepared by the preparation method according to any one of claims 1 to 4 in near-infrared imaging.

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