Rare earth-based lead-free halide double perovskite luminescent material, preparation method and application thereof

Abstract

This invention proposes a rare-earth-based lead-free halide double perovskite luminescent material, its preparation method, and its application, belonging to the field of optoelectronic luminescent material technology. The method includes: weighing 4 mmol CsCl, 2(1-x) mmol NaCl, 2x mmol AgCl, (1-y) mmol Sc2O3, and 2y mmol BiCl3 into 5 mL of hydrochloric acid solution and stirring to dissolve, obtaining a mixed Cs2Na... 1‑x Ag x Sc 1‑y Bi y A Cl6 perovskite solution was heated and stirred at 120°C for 15 hours on a magnetic stirrer, followed by standing at room temperature for 1 hour to obtain Cs2Na. 1‑x Ag x Sc 1‑ y Bi y Cl6 perovskite sample solution; the perovskite sample solution was centrifuged three times, and washed with ethanol after each centrifugation, and then dried in an oven at 60℃ to obtain Cs2Na. 1‑ x Ag x Sc 1‑y Bi y Cl6 powder. Cs2Na 0.9 Ag 0.1 Sc 0.95 Bi 0.05 Cl6 exhibits the best luminescence intensity. This invention also discloses the application of rare-earth-based lead-free halide double perovskite luminescent materials in the preparation of luminescent thin films. The rare-earth-based lead-free halide double perovskite luminescent materials prepared by this invention possess excellent thermal stability, require simple equipment, have low cost, and the results are easily reproducible.

Description

Technical Field

[0001] This invention belongs to the field of optoelectronic luminescent materials technology, and particularly relates to a rare earth-based lead-free halide double perovskite luminescent material, its preparation method, and its application. Background Technology

[0002] Metal halide perovskite materials, due to their excellent optoelectronic properties such as high light absorption coefficient, high carrier mobility, and tunable bandgap, have shown broad application prospects in fields such as solar cells, light-emitting diodes, and photodetectors. However, traditional lead-based perovskite (APbX3) materials contain the toxic element lead, whose toxicity not only poses a threat to human health but also easily causes environmental pollution, severely restricting their large-scale commercial application. Furthermore, the inherent chemical instability of lead-based perovskite materials, their sensitivity to humidity, heat, and light, and their tendency to undergo structural decomposition, leading to device performance degradation, further hinders their practical application.

[0003] To address the toxicity and stability issues of lead-based perovskites, researchers have developed a lead-free double perovskite (A2B'B''X6) material system. This structure, by replacing two divalent Pb²⁺ ions with one monovalent B' ion (such as Ag⁺ or Na⁺) and one trivalent B'' ion (such as Bi³⁺ or Sb³⁺), not only maintains the stability of the three-dimensional perovskite structure but also exhibits advantages such as structural diversity, tunable composition, and environmental friendliness. It is considered a key research direction for replacing lead-based perovskites and has enormous potential in optoelectronics, particularly in light-emitting displays.

[0004] Among numerous lead-free double perovskite systems, rare-earth-based double perovskites have attracted much attention due to their unique electronic structure and photophysical properties. Rare earth elements possess abundant 4f energy levels, and their ff or fd transitions can produce sharp or broadband emission covering the visible to near-infrared bands, making them ideal luminescent centers for achieving efficient and stable luminescence.

[0005] Cs₂NaScCl₆, as a typical rare-earth-based lead-free halide double perovskite material, possesses a stable face-centered cubic structure (space group Fm-3m) and good environmental adaptability. Its unique [ScCl₆]³⁻ and [NaCl₆]... 5 Octahedral structures form a three-dimensional perovskite framework. Studies show that this material, under ultraviolet light excitation, can produce compounds derived from [ScCl6]³⁻ and [NaCl6], respectively. 5- Octahedral Cs₂NaScCl₆ exhibits dual-band self-trapped exciton emission in both blue and near-infrared wavelengths. However, undoped Cs₂NaScCl₆ exhibits extremely weak intrinsic luminescence, with quantum yields of only 3.2% for blue light and 2.7% for near-infrared emission. This phenomenon is mainly due to its highly symmetrical crystal structure, which makes it difficult for excitons to effectively trap, and the excitation energy is easily captured by lattice defects and dissipated in a non-radiative manner. This severely limits the practical application of this material system in fields such as light-emitting diodes, display lighting, and bioimaging. Therefore, how to effectively activate the luminescent properties of Cs₂NaScCl₆ has become a key scientific problem that urgently needs to be solved.

[0006] To address the activation problem of luminescence in double perovskites, researchers have published various control strategies. Ag+ alloying has been shown to effectively break lattice symmetry, induce local structural distortions, and promote exciton trapping, thereby significantly improving luminescence efficiency. For example, in Cs2AgBiCl... 6 The system achieved efficient near-infrared luminescence of rare earth ions by controlling the local structure through a Na / Ag alloying strategy. Bi³ + Doping, due to its unique 6s² electronic configuration, can effectively control the electronic band structure, enhance ultraviolet absorption, and affect emission wavelength characteristics. However, single-ion doping or alloying strategies result in insufficient luminescence intensity and low quantum efficiency. Summary of the Invention

[0007] The purpose of this invention is to provide a rare earth-based lead-free halide double perovskite luminescent material, its preparation method, and its application, in order to solve the technical problems of extremely weak intrinsic luminescence of undoped Cs2NaScCl6 in the prior art, insufficient luminescence intensity, and low quantum efficiency caused by single ion doping or alloying strategies.

[0008] To solve the above-mentioned technical problems, the specific technical solution of the present invention is as follows:

[0009] This invention discloses a method for preparing rare-earth-based lead-free halide double perovskite luminescent materials, the method comprising the following steps:

[0010] Step S1: Weigh 4 mmol of cesium chloride, 2(1-x) mmol of sodium chloride, 2x mmol of silver chloride, (1-y) mmol of scandium trioxide, and 2y mmol of bismuth chloride into 5 mL of hydrochloric acid solution and stir to dissolve, obtaining a mixed Cs₂Na 1-x Ag x Sc 1-y Bi y Cl6 perovskite solution;

[0011] Step S2: Mix Cs2Na 1-x Ag x Sc 1-y Bi yThe Cl6 perovskite solution was placed on a magnetic stirrer and heated and stirred at 120°C for 15 hours. After the reaction was completed, it was allowed to stand at room temperature for 1 hour to obtain Cs2Na. 1-x Ag x Sc 1-y Bi y Cl6 perovskite sample solution;

[0012] Step S23: For Cs2Na 1-x Ag x Sc 1-y Bi y The Cl6 perovskite sample solution was centrifuged three times, and after each centrifugation, it was washed with ethanol as a washing agent, and then dried in a 60°C oven to obtain Cs2Na. 1-x Ag x Sc 1-y Bi y Cl6 powder, resulting in Cs2Na 1-x Ag x Sc 1-y Bi y Cl6 powder is a rare-earth-based lead-free halide double perovskite luminescent material.

[0013] Furthermore, the value of x ranges from 0.1 to 0.5.

[0014] Furthermore, the value of y ranges from 0.01 to 0.2.

[0015] Furthermore, when x is 0.1 and y is 0.05, the resulting rare-earth-based lead-free halide double perovskite luminescent material exhibits the best luminescence intensity, i.e., Cs₂Na 0.9 Ag 0.1 Sc 0.95 Bi 0.05 Cl6 exhibits the best luminescence intensity.

[0016] This invention also discloses a rare-earth-based lead-free halide double perovskite luminescent material prepared by the above method, wherein the rare-earth-based lead-free halide double perovskite luminescent material is Cs2Na. 1-x Ag x Sc 1-y Bi y Cl6 powder is a white, micron-sized powder.

[0017] Furthermore, when x is 0.1 and y is 0.05, the luminescence intensity of the rare earth-based lead-free halide double perovskite luminescent material is optimal, i.e., Cs₂Na 0.9 Ag 0.1 Sc 0.95 Bi 0.05 Cl6 exhibits the best luminescence intensity.

[0018] Furthermore, this invention discloses the application of the rare-earth-based lead-free halide double perovskite luminescent material in luminescent thin films:

[0019] Step S11: Weigh the A and B components of the epoxy resin AB adhesive at a weight ratio of 3:1 and add them to a 10 ml plastic cup to obtain a well mixed epoxy resin AB adhesive.

[0020] Step S12: Mix the rare earth-based lead-free halide double perovskite luminescent material with epoxy resin AB glue at a ratio of 1.5:1 and stir until homogeneous to obtain a mixed solution.

[0021] Step S13: Use a rubber dropper to draw up the mixed solution and drop it onto a 2×2 quartz substrate. Cover it with another quartz substrate of the same size to spread the mixed solution evenly and obtain the assembly.

[0022] Step S14: Place the assembly in a 60°C oven to cure, and obtain a cured luminescent film; the luminescent film is pale yellow and emits bright yellow light under ultraviolet light.

[0023] Furthermore, this invention discloses the application of the luminescent thin film prepared from the rare earth-based lead-free halide double perovskite luminescent material: integrating an ultraviolet lamp, a luminescent thin film, and visible and near-infrared cameras to construct a multifunctional lighting and imaging system.

[0024] Compared with the prior art, the present invention has the following beneficial technical effects:

[0025] 1) This invention involves doping typical rare-earth-based lead-free halide double perovskite material Cs2NaScCl6 with Ag+ and Bi. 3 + By introducing Ag⁺ to break the lattice symmetry and induce exciton self-trapping, and by doping Bi³⁺ to regulate the band structure and enhance absorption, the synergistic effect of the two significantly improves the luminescence performance.

[0026] 2) The material of the present invention has excellent thermal stability and extends to a portion of near-infrared luminescence.

[0027] 3) The thin film prepared based on the phosphor of this invention can be applied to multiple application scenarios such as warm white light illumination and reflection vein imaging, showing good practical value.

[0028] 4) The equipment used in this invention is simple, the cost is low, and the results are easy to reproduce. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the preparation method of the rare earth-based lead-free halide double perovskite luminescent material of the present invention.

[0031] Figure 2 Cs2Na prepared according to the present invention 1-x Ag x Sc 0.99 Bi 0.01 Schematic diagram of emission spectrum intensity curves of Cl6 at different x values.

[0032] Figure 3 Cs2Na prepared according to the present invention 0.9 Ag 0.1 Sc 1-y Bi y Schematic diagram of emission spectrum intensity curves of Cl6 at different y values.

[0033] Figure 4 This invention relates to a rare-earth-based lead-free halide double perovskite luminescent material, Cs2Na. 0.9 Ag 0.1 Sc 0.95 Bi 0.05 A schematic diagram of the quantum efficiency data for Cl6.

[0034] Figure 5 This is a schematic diagram of the light-emitting thin film prepared according to the present invention.

[0035] Figure 6 This is a schematic diagram of the multifunctional lighting and imaging system of the present invention.

[0036] Figure 7 This is a schematic diagram illustrating how the present invention illuminates leaves under 365nm commercial ultraviolet light. Detailed Implementation

[0037] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] This invention proposes a method for preparing rare-earth-based lead-free halide double perovskite luminescent materials, which involves co-doping the rare-earth-based lead-free halide double perovskite material Cs₂NaScCl₆ with Ag⁺ and Bi⁺. 3+ This enhances luminescence and solves the technical problems of extremely weak intrinsic luminescence of undoped Cs2NaScCl6 and insufficient luminescence intensity of single-doped Cs2NaScCl6.

[0039] Example 1

[0040] A method for preparing a rare-earth-based lead-free halide double perovskite luminescent material, such as Figure 1 As shown, the method includes the following steps:

[0041] Step S11: Weigh 4 mmol of cesium chloride (CsCl), 2 mmol of sodium chloride (NaCl) and 1 mmol of scandium trioxide (Sc2O3) and mix them in a 20 mL glass bottle. Then add 5 mL of hydrochloric acid (HCl) and stir to dissolve, so as to obtain a mixed Cs2NaScCl6 perovskite solution.

[0042] Furthermore, the purity of cesium chloride, sodium chloride, and scandium trioxide is 99.99%; the concentration of hydrochloric acid is 37 wt%.

[0043] Step S12: Place the mixed Cs2NaScCl6 perovskite solution on a magnetic stirrer and heat and stir at 120°C for 15 hours. After the reaction is complete, let it stand at room temperature for 1 hour to obtain the Cs2NaScCl6 perovskite sample solution.

[0044] Step S13: The Cs2NaScCl6 perovskite sample solution was centrifuged three times. After each centrifugation, it was washed with ethanol as a detergent and then dried in an oven at 60°C to obtain Cs2NaScCl6 powder.

[0045] The obtained Cs2NaScCl6 powder is a rare earth-based lead-free halide double perovskite luminescent material.

[0046] Example 2

[0047] A method for preparing rare earth-based lead-free halide double perovskite luminescent materials, involving co-doping Cs₂NaScCl₆ with Ag⁺ and Bi⁺. 3+ Bi 3+ The doping amount is controlled at 1%; the method includes the following steps:

[0048] Step S21: Weigh 4 mmol of cesium chloride (CsCl), 2(1-x) mmol of sodium chloride (NaCl), 2x mmol of silver chloride (AgCl), 0.99 mmol of scandium trioxide (Sc2O3), and 0.02 mmol of bismuth chloride (BiCl3) into 5 mL of hydrochloric acid (HCl) solution and stir to dissolve, obtaining a mixed Cs2Na 1-x Ag x Sc 0.99 Bi 0.01 Cl6 perovskite solution.

[0049] Furthermore, the purity of cesium chloride, sodium chloride, and scandium trioxide is 99.99%; the purity of bismuth chloride is AR; the purity of silver chloride is 99.99%; and the concentration of hydrochloric acid is 37 wt%.

[0050] Step S22: Mix Cs2Na 1-x Ag x Sc 0.99 Bi 0.01 The Cl6 perovskite solution was placed on a magnetic stirrer and heated and stirred at 120°C for 15 hours. After the reaction was completed, it was allowed to stand at room temperature for 1 hour to obtain Cs2Na. 1-x Ag x Sc 0.99 Bi 0.01 Cl6 perovskite sample solution.

[0051] Step S23: For Cs2Na 1-x Ag x Sc 0.99 Bi 0.01 The Cl6 perovskite sample solution was centrifuged three times, and after each centrifugation, it was washed with ethanol as a washing agent, and then dried in a 60°C oven to obtain Cs2Na. 1- x Ag x Sc 0.99 Bi 0.01 Cl6 powder.

[0052] The obtained Cs2Na 1-x Ag x Sc 0.99 Bi 0.01 Cl6 powder is a rare-earth-based lead-free halide double perovskite luminescent material.

[0053] Cs2Na 1-x Ag x Sc 0.99 Bi 0.01The Na and Ag contents in Cl6 are altered by changing the x-value in the reaction mixture of sodium chloride and silver chloride. Following steps S21-S23, Cs2Na is prepared for five conditions: x=0.1, 0.2, 0.3, 0.4, and 0.5. 1-x Ag x Sc 0.99 Bi 0.01 Cl6 powder. The concentrations of Cs₂NaScCl₆ and Cs₂Na at different x values ​​were measured using an integrated spectrometer. 1- x Ag x Sc 0.99 Bi 0.01 The emission spectrum of Cl6 was obtained, and the emission intensity curve is shown below. Figure 2 As shown, from Figure 2 It can be seen that when x is 0.1, i.e., Na / Ag = 9:1, Cs2Na 1-x Ag x Sc 0.99 Bi 0.01 Cl6 powder achieved the highest luminescence intensity, which was 329 times that of Cs2NaScCl6.

[0054] Example 3

[0055] A method for preparing a rare-earth-based lead-free halide double perovskite luminescent material, wherein the Na to Ag doping ratio is controlled at 9:1, the method comprising the following steps:

[0056] Step S31: Step S21: Weigh 4 mmol of cesium chloride (CsCl), 1.8 mmol of sodium chloride (NaCl), 0.2 mmol of silver chloride (AgCl), (1-y) mmol of scandium trioxide (Sc2O3), and 2y mmol of bismuth chloride (BiCl3) into 5 mL of hydrochloric acid (HCl) solution and stir to dissolve, obtaining a mixed Cs2Na 0.9 Ag 0.1 Sc 1-y Bi y Cl6 perovskite solution.

[0057] Furthermore, the purity of cesium chloride, sodium chloride, and scandium trioxide is 99.99%; the purity of bismuth chloride is AR; the purity of silver chloride is 99.99%; and the concentration of hydrochloric acid is 37 wt%.

[0058] Step S22: Mix Cs2Na 0.9 Ag 0.1 Sc 1-y Bi yThe Cl6 perovskite solution was placed on a magnetic stirrer and heated and stirred at 120°C for 15 hours. After the reaction was completed, it was allowed to stand at room temperature for 1 hour to obtain Cs2Na. 0.9 Ag 0.1 Sc 1-y Bi y Cl6 perovskite sample solution.

[0059] Step S23: For Cs2Na 0.9 Ag 0.1 Sc 1-y Bi y The Cl6 perovskite sample solution was centrifuged three times, and after each centrifugation, it was washed with ethanol as a washing agent, and then dried in a 60°C oven to obtain Cs2Na. 0.9 Ag 0.1 Sc 1-y Bi y Cl6 powder.

[0060] The obtained Cs2Na 0.9 Ag 0.1 Sc 1-y Bi y Cl6 powder is a rare-earth-based lead-free halide double perovskite luminescent material.

[0061] Cs2Na 0.9 Ag 0.1 Sc 1-y Bi y The contents of Sc and Bi in Cl6 are altered by changing the y content in Sc2O3 and BiCl3. Following steps S31 to S33, Cs2Na is prepared under eight conditions: y = 0.001, 0.005, 0.01, 0.03, 0.05, 0.1, 0.15, and 0.2. 0.9 Ag 0.1 Sc 1-y Bi y Cl6 powder. Cs₂Na at different y values ​​was measured using an integrated spectrometer. 0.9 Ag 0.1 Sc 1-y Bi y The emission spectrum of Cl6 was obtained, and the emission intensity curve is shown below. Figure 3 As shown, from Figure 3 It can be seen that when Bi 3+ At a concentration of 5%, the emission spectrum reaches its optimal luminescence intensity, which is relative to Cs₂Na. 0.9 Ag 0.1 Sc 0.99 Bi 0.01 Cl6 showed a 2.6-fold increase in luminescence, which is 855 times higher than that of Cs2NaScCl6.

[0062] As can be seen from the above embodiments, the optimal rare-earth-based lead-free halide double perovskite luminescent material is Cs₂Na. 0.9 Ag 0.1 Sc 0.95 Bi 0.05 Cl6 is a white, micron-sized powder.

[0063] The introduction of Ag⁺ disrupts lattice symmetry and induces exciton trapping, while Bi³⁺ doping modulates the band structure and enhances absorption. The synergistic effect of these two agents significantly improves luminescence performance, achieving an 855-fold increase compared to the matrix Cs₂NaScCl₆. The fluorescence quantum efficiency reaches its best level within this material system. Figure 4 As shown, Cs2Na 0.9 Ag 0.1 Sc 0.95 Bi 0.05 Cl6 has an internal quantum efficiency of 76.7%, an absorption efficiency of 64.9%, and an external quantum efficiency of 49.7%.

[0064] Example 4 Cs2Na 0.9 Ag 0.1 Sc 0.95 Bi 0.05 Applications of Cl6

[0065] Step S41: Weigh the A and B components of the epoxy resin AB adhesive at a weight ratio of 3:1 and add them to a 10 ml plastic cup to obtain a well mixed epoxy resin AB adhesive.

[0066] Step S42: Add Cs2Na 0.9 Ag 0.1 Sc 0.95 Bi 0.05 Cl6 powder and epoxy resin AB glue are mixed and stirred evenly at a ratio of 1.5:1 to obtain a mixed solution.

[0067] Step S43: Use a rubber dropper to draw up the mixed solution and drop it onto a 2×2 quartz substrate. Cover it with another quartz substrate of the same size to spread the mixed solution evenly and obtain the assembly.

[0068] Step S44: Place the assembly in a 60°C oven to cure, and obtain a cured luminescent film.

[0069] Furthermore, the luminescent film is pale yellow and emits bright yellow light under commercial ultraviolet light irradiation. The commercial ultraviolet light used is 365 nm. Figure 5 As shown.

[0070] Furthermore, by integrating ultraviolet lamps, luminescent films, and visible and near-infrared cameras, a multifunctional lighting and imaging system can be constructed, such as... Figure 6As shown, the constructed multifunctional lighting and imaging system uses a commercial 365nm ultraviolet lamp as the excitation source, which illuminates a light-emitting film. The light emitted from the film then shines onto the leaves, and a visual camera is used to photograph the leaves and observe their brightness and darkness. Figure 7 As shown, with leaves as the object of illumination, the environment is dim when the ultraviolet light is not turned on. After the ultraviolet light is turned on, the film emits light to illuminate the leaves, and the details of the leaf veins are clearly visible.

[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a rare-earth-based lead-free halide double perovskite luminescent material, characterized in that, The method includes the following steps: Step S1: Weigh 4 mmol of cesium chloride, 2(1-x) mmol of sodium chloride, 2x mmol of silver chloride, (1-y) mmol of scandium trioxide, and 2y mmol of bismuth chloride into 5 mL of hydrochloric acid solution and stir to dissolve, obtaining a mixed Cs₂Na 1-x Ag x Sc 1-y Bi y Cl6 perovskite solution; Step S2: Mix Cs2Na 1-x Ag x Sc 1-y Bi y The Cl6 perovskite solution was placed on a magnetic stirrer and heated and stirred at 120°C for 15 hours. After the reaction was completed, it was allowed to stand at room temperature for 1 hour to obtain Cs2Na. 1-x Ag x Sc 1-y Bi y Cl6 perovskite sample solution; Step S23: For Cs2Na 1-x Ag x Sc 1-y Bi y The Cl6 perovskite sample solution was centrifuged three times, and after each centrifugation, it was washed with ethanol as a washing agent, and then dried in a 60°C oven to obtain Cs2Na. 1-x Ag x Sc 1-y Bi y Cl6 powder, resulting in Cs2Na 1-x Ag x Sc 1-y Bi y Cl6 powder is a rare-earth-based lead-free halide double perovskite luminescent material.

2. The method for preparing rare earth-based lead-free halide double perovskite luminescent material according to claim 1, characterized in that, The value of x ranges from 0.1 to 0.

5.

3. The method for preparing rare earth-based lead-free halide double perovskite luminescent material according to claim 1, characterized in that, The value of y ranges from 0.01 to 0.

2.

4. The method for preparing rare earth-based lead-free halide double perovskite luminescent material according to claim 1, characterized in that, When x is 0.1 and y is 0.05, the luminescence intensity of the obtained rare-earth-based lead-free halide double perovskite luminescent material is optimal, i.e., Cs₂Na 0.9 Ag 0.1 Sc 0.95 Bi 0.05 Cl6 exhibits the best luminescence intensity.

5. A rare-earth-based lead-free halide double perovskite luminescent material, characterized in that, The rare-earth-based lead-free halide double perovskite luminescent material is prepared by the method described in any one of claims 1-4, and the rare-earth-based lead-free halide double perovskite luminescent material is Cs2Na. 1-x Ag x Sc 1-y Bi y Cl6 powder is a white, micron-sized powder.

6. The rare-earth-based lead-free halide double perovskite luminescent material according to claim 5, characterized in that, When x is 0.1 and y is 0.05, the luminescence intensity of the rare earth-based lead-free halide double perovskite luminescent material is optimal, i.e., Cs₂Na 0.9 Ag 0.1 Sc 0.95 Bi 0.05 Cl6 exhibits the best luminescence intensity.

7. The application of the rare-earth-based lead-free halide double perovskite luminescent material prepared by the method of any one of claims 1-4, or the rare-earth-based lead-free halide double perovskite luminescent material of claim 5 or 6, in luminescent thin films, characterized in that... Step S11: Weigh the A and B components of the epoxy resin AB adhesive at a weight ratio of 3:1 and add them to a 10 ml plastic cup to obtain a well mixed epoxy resin AB adhesive. Step S12: Mix the rare earth-based lead-free halide double perovskite luminescent material with epoxy resin AB glue at a ratio of 1.5:1 and stir until homogeneous to obtain a mixed solution. Step S13: Use a rubber dropper to draw up the mixed solution and drop it onto a 2×2 quartz substrate. Cover it with another quartz substrate of the same size to spread the mixed solution evenly and obtain the assembly. Step S14: Place the assembly in a 60°C oven to cure, and obtain a cured luminescent film; the luminescent film is pale yellow and emits bright yellow light under ultraviolet light.

8. The application of the luminescent thin film prepared from the rare-earth-based lead-free halide double perovskite luminescent material according to claim 7, characterized in that, By integrating ultraviolet lamps, luminescent films, and visible and near-infrared cameras, a multifunctional lighting and imaging system is constructed.

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