A method for preparing europium-doped Cs3MnX5 light emitters

Abstract

This invention provides a method for preparing europium-doped Cs3MnX5 luminescent material, comprising the following steps: S1: dissolving cesium halide, manganese halide, and europium halide in a solvent and performing wet milling to form a precursor solution; then heating the precursor solution to evaporate the solvent to form the doped Eu. 2+ The crude product of Cs3MnX5. This invention utilizes Eu, which has a banded spectrum, is relatively stable, and decays rapidly. 2+ Doping into Cs3MnX5 emitting diodes to achieve Eu 2+ and Mn 2+ The co-emission of two ions enhances the luminescence intensity and stability of the luminescent material.

Description

Technical Field

[0001] This invention belongs to the field of perovskite luminescent material synthesis technology, and particularly relates to a method for preparing europium-doped Cs3MnX5 luminescent materials. Background Technology

[0002] Metal halide perovskite luminescent materials, due to their unique crystal structure, possess excellent optoelectronic properties such as high fluorescence quantum efficiency, narrow emission peak, and tunable band gap, attracting widespread attention. They have significant application prospects in fields such as lighting, displays, solar energy, lasers, and anti-counterfeiting, and have developed rapidly in a short period of time.

[0003] However, currently reported perovskite materials with excellent optoelectronic properties are all based on lead-based organic-inorganic hybrid perovskites, lead-based all-inorganic perovskites, or cadmium-based perovskites. Cadmium and lead are highly polluting and easily accumulate in organisms, posing a significant threat to the ecological environment and human health, thus hindering the large-scale use and promotion of perovskite materials. Therefore, developing novel lead-free and cadmium-free perovskite materials is crucial for the development of perovskite materials and their optoelectronic devices.

[0004] Chinese Patent Publication No. CN 112694888 A discloses a microwave-assisted liquid-phase synthesis of a narrowband green phosphor and its synthesis method. The synthesis method specifically includes the following steps:

[0005] 1) Weigh out cesium bromide and manganese bromide according to the stoichiometric ratio of the elements in the general chemical formula Cs3MnBr5, mix them, add them to deionized water, and shake until the solution is clear to obtain a clear solution.

[0006] 2) Place the clear solution in a microwave oven with a power of 600-900W and microwave it for 1-10 minutes. After the reaction is complete, a pale green narrow-band green phosphor is obtained.

[0007] When heating in a microwave oven, the heat energy comes from the magnetron mounted on the top of the oven. The high-frequency electromagnetic waves emitted by the magnetron can immediately penetrate into the interior of the cesium bromide and manganese bromide solution. At this point, the microwaves encounter polar molecules (water molecules), causing violent molecular oscillations and rapidly generating a large amount of heat through intermolecular friction. During microwave heating, the material is heated simultaneously from the inside out, resulting in uniform heating and a rapid temperature rise, thus significantly shortening the heating time. Furthermore, there is no heat conduction process through the surrounding air during heating, resulting in high heating efficiency.

[0008] However, the Cs3MnBr5 prepared by the above-mentioned prior art is in a bare state, and no shell (i.e., coating layer) is built on the surface of Cs3MnBr5. As a result, Cs3MnBr5 is directly exposed to water, oxygen, light and heat, which is insufficient in terms of stability and therefore needs to be improved. Summary of the Invention

[0009] The purpose of this invention is to provide a method for preparing europium-doped Cs3MnX5 luminescent materials. This method utilizes europium-doped Cs3MnX5 luminescent materials, which have a banded spectrum, are relatively stable, and decay rapidly. 2+ Doping into Cs3MnX5 emitting diodes to achieve Eu 2+ and Mn 2+ The co-emission of two ions enhances the luminescence intensity and stability of the luminescent material.

[0010] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0011] A method for preparing a europium-doped Cs3MnX5 luminescent material includes the following steps:

[0012] S1: Cesium halide, manganese halide, and europium halide are dissolved in a solvent and wet-milled to form a precursor solution; then the precursor solution is heated to evaporate the solvent, thereby forming doped Eu. 2+ The crude product of Cs3MnX5, where X is a halogen.

[0013] Furthermore, the cesium halide includes cesium bromide, cesium iodide, and combinations thereof;

[0014] The manganese halide includes manganese bromide, manganese iodide, and combinations thereof;

[0015] The europium halides include europium bromide, europium iodide, and combinations thereof.

[0016] Furthermore, the solvent in step S1 includes water, ethanol, and combinations thereof.

[0017] Furthermore, the wet grinding time in step S1 is 10-50 minutes.

[0018] Furthermore, it also includes step S2 and post-processing:

[0019] The crude product obtained from S1 was annealed at 140-180℃ for 15-25 min to obtain Eu-doped material. 2+ Cs3MnX5 luminescent material.

[0020] By adopting the above scheme: through the post-processing step of annealing, the doping of Eu is achieved. 2+ The crude Cs3MnX5 product was recrystallized to obtain Eu-doped material with better luminescent properties. 2+ Cs3MnX5 luminescent material.

[0021] Furthermore, step S1 includes the following steps:

[0022] A1: Cesium halide, manganese halide, and europium halide are dissolved in a solvent and wet-milled to form a precursor solution;

[0023] A2: The precursor solution is adsorbed into the pores through a micro / mesoporous template to obtain a spatially confined luminescent intermediate;

[0024] A3: Place the spatially confined luminescent intermediate in a microwave oven, turn on the microwave, adjust the power to 50-100W, and set the microwave time to 1-8 minutes. Microwave heating causes the precursor solution to react within the micro / mesoporous template, forming doped Eu. 2+ Cs3MnX5 luminescent material.

[0025] By adopting the above scheme, the microwave power of this invention is 50-100W, far lower than the 600-900W in the prior art. As is well known, the higher the microwave power, the greater the energy it carries, meaning more energy is transferred to the object being heated. Therefore, there is a positive correlation between microwave power and heating temperature.

[0026] In another respect, temperature is a macroscopic manifestation of the intensity of molecular motion. As temperature increases, the speed of molecular motion accelerates, and the frequency and intensity of collisions between molecules increase. While existing technologies promote reactions by increasing microwave power, this invention takes a different approach. The technical principle is as follows:

[0027] The present invention pre-adsorbs the precursor solution within the pores of the micro / mesoporous template, thereby constructing a spatially confined luminescent intermediate for the precursor solution within the pores of the micro / mesoporous template.

[0028] Because microwave heating heats the material simultaneously from the inside out, resulting in uniform heating and a rapid temperature rise, it significantly shortens the heating time. The precursor solution evaporates within a confined space in a short time, causing a large amount of vapor to instantaneously form within the pores of the micro / mesoporous template. This vapor is difficult to dissipate quickly within the template. According to the ideal gas law: P × V = n × R × T, where n is the number of moles of gas and R is the universal gas constant, the instantaneous generation of a large amount of vapor within this confined space leads to an increase in pressure within the pores of the micro / mesoporous template, resulting in an instantaneous pressure greater than the external atmospheric pressure. Under continuous microwave heating, the vapor temperature within the pores of the micro / mesoporous template rises, providing more energy for the perovskite precursor solution to react and form Cs3MnX5 crystals.

[0029] Furthermore, the micro / mesoporous template is a microporous material and / or a mesoporous material;

[0030] The microporous material is at least one of microporous molecular sieve, microporous silica, microporous titanium dioxide, microporous alumina, microporous transition metal oxide, microporous sulfide, microporous silicate, microporous aluminate or microporous transition metal nitride.

[0031] The mesoporous material is at least one of the following: mesoporous molecular sieve, mesoporous silica, mesoporous titanium dioxide, mesoporous alumina, mesoporous carbon, mesoporous transition metal oxide, mesoporous sulfide, mesoporous silicate, mesoporous aluminate, or mesoporous transition metal nitride.

[0032] The beneficial effects of this invention are mainly reflected in:

[0033] (1) This invention provides an Eu 2+ A method for synthesizing doped lead-free perovskite Cs3MnX5 luminescent materials is presented. The preparation method is simple, yielding luminescent materials with dual-ion luminescence, high luminescence efficiency, and good stability. This invention provides two methods for heating and annealing the precursor solution: 1. Annealing at 140-180℃ for 15-25 min; 2. Heating the precursor solution located within the pores of a micro / mesoporous template under microwave heating.

[0034] (2) Under microwave heating, the precursor solution located within the pores of the micro / mesoporous template is heated. During the heating process, water is first evaporated to form water vapor. The spatial confinement effect provided by the micro / mesoporous template effectively controls the size of Cs3MnX5 grown within the pores, ultimately obtaining nanoscale Cs3MnX5 crystals (nanocrystalline). On the other hand, a large amount of vapor is instantaneously generated within the pores of the micro / mesoporous template. This large amount of vapor is difficult to dissipate quickly within the micro / mesoporous template, thus creating an environment with a pressure higher than the external atmospheric pressure within the pores of the micro / mesoporous template in a short period of time. Therefore, under continuous microwave heating, the vapor temperature within the pores of the micro / mesoporous template will increase, thereby providing more energy for the precursor solution to react and form Cs3MnX5. By changing the existing microwave reaction process and reducing the microwave power, the cost burden caused by energy consumption can be reduced in the next industrial scale-up stage. Attached Figure Description

[0035] Figure 1 This is a comparison chart of the PL luminescence intensity of Embodiment 1 and Comparative Example 1 of the present invention;

[0036] Figure 2 The X-ray diffraction pattern of the Cs3MnI5 luminescent material synthesized in Example 1 of this invention;

[0037] Figure 3 This is a comparison chart of the PL luminescence intensity of Example 2 and Comparative Example 2 of the present invention;

[0038] Figure 4 This is a comparison chart of the PL luminescence intensity of Example 1 and Comparative Example 3 of the present invention;

[0039] Figure 5 The image shows the X-ray diffraction pattern of the product of Comparative Example 3. Detailed Implementation

[0040] To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the invention is further described in detail below. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0041] Example 1:

[0042] S1: Dissolve 119.6 mg CsI, 58.4 mg MnI2·4H2O and 3.2 mg EuI2 in 200 μL of water and wet grind them. After they are fully dissolved, dry them in an oven at 60℃.

[0043] S2: Anneal the product obtained in step S1 at 160℃ for 20 min to obtain Eu-doped product. 2+ Cs3MnI5 luminescent material.

[0044] Experimental analysis: The product obtained in step S2 was subjected to photoluminescence testing, such as... Figure 1 As shown, its luminescence intensity is greater than that of undoped Eu. 2+ Cs3MnI5 luminescent material. For example... Figure 2 As shown, this is the doped Eu synthesized in Example 1. 2+ X-ray diffraction pattern of Cs3MnI5 luminescent material.

[0045] Example 2:

[0046] S1: Dissolve 130.2 mg CsBr, 58.4 mg MnBr2·4H2O and 3.2 mg EuBr2 in 200 μL of water and wet grind them. After they are fully dissolved, dry them in an oven at 60℃.

[0047] S2: Anneal the product obtained in step S1 at 160℃ for 20 min to obtain Eu-doped product. 2+ Cs3MnBr5 luminescent material.

[0048] Experimental analysis: The product obtained in step S2 was subjected to photoluminescence testing, such as... Figure 3 As shown, its luminescence intensity is greater than that of undoped Eu. 2+ Cs3MnBr5 luminescent material.

[0049] Example 3:

[0050] A1: Dissolve 119.6 mg CsI, 58.4 mg MnI2·4H2O, and 3.2 mg EuI2 in 200 μL of water and wet grind them until fully dissolved to form a precursor solution.

[0051] A2: Pour the precursor solution from step A1 and 480mg of template agent MCM-41 into separate bottles and stir well to allow the precursor solution to be adsorbed into the pores of the template agent MCM-41.

[0052] A3: Place the bottle in the microwave oven, turn on the microwave, adjust the power to 100W, and set the time to 8 minutes. Microwave heating will cause the precursor solution to react in the template agent to form doped Eu. 2+ Cs3MnI5 luminescent material.

[0053] Comparative Example 1:

[0054] The difference from Example 1 is that it does not contain Eu. 2+ .

[0055] S1: Dissolve 119.6 mg CsI and 58.4 mg MnI2·4H2O in 200 μL of water and wet grind them. After they are fully dissolved, dry them in an oven at 60℃.

[0056] S2: Anneal the product obtained in step S1 at 160℃ for 20 min to obtain undoped Eu. 2+ Cs3MnI5 luminescent material.

[0057] Comparative Example 2:

[0058] The difference from Example 2 is that Eu was not added. 2+ .

[0059] S1: Dissolve 130.2 mg CsBr and 58.4 mg MnBr2·4H2O in 200 μL of water and wet grind them. After they are fully dissolved, dry them in an oven at 60℃.

[0060] S2: Anneal the product obtained in step S1 at 160℃ for 20 min to obtain undoped Eu. 2+ Cs3MnBr5 luminescent material.

[0061] Comparative Example 3:

[0062] The difference from Example 1 is that dry grinding is used.

[0063] S1: Place 119.6 mg CsI, 58.4 mg MnI2·4H2O and 3.2 mg EuI2 in a mortar and grind them thoroughly.

[0064] S2: Anneal the product obtained in step S1 at 160°C for 20 minutes to obtain aggregates of CsI and a small amount of luminescent material.

[0065] Experimental analysis: The product obtained in step S2 was subjected to photoluminescence testing, such as... Figure 4 As shown, its luminescence intensity is lower than that of the Cs3MnI5 luminescent material prepared by wet grinding. Figure 5 The image shown is an X-ray diffraction pattern of the non-Cs3MnI5 phase luminescent material synthesized in Comparative Example 3.

[0066] Although the MnI₂·4H₂O used in Comparative Example 3 contains trace amounts of water, it is still insufficient to dissolve the precursor raw materials. Figure 5 It can be seen that the product contains a large amount of CsI, indicating that a large amount of raw materials did not react when dry grinding was used, so the synthesized product is an aggregate of CsI and a small amount of luminescent material.

[0067] Comparative Example 4:

[0068] The difference from Example 3 is that step A2 is not present.

[0069] A1: Dissolve 119.6 mg CsI, 58.4 mg MnI2·4H2O, and 3.2 mg EuI2 in 200 μL of water and wet grind them until fully dissolved to form a precursor solution.

[0070] A3: Place the bottle in the microwave oven, turn on the microwave, adjust the power to 100W, and set the time to 8 minutes. Microwave heating will cause the precursor solution to react and form doped Eu. 2+ Cs3MnI5 luminescent material.

[0071] Experimental analysis: Since Comparative Example 4 does not have the spatial confinement effect provided by MCM-41 molecular sieve, the vapor generated by microwave heating of the precursor solution dissipates rapidly into the air, resulting in a microwave reaction temperature for the precursor solution that is actually lower than that of Example 1 (i.e., the heat energy contained in the vapor cannot be utilized), so the reaction does not proceed completely.

[0072] Experimental Analysis: The final products prepared in the above examples (or comparative examples) were tested under strong blue light irradiation (350mW / cm²) at 120℃. 2 The stability in the environment is shown in Table 1.

[0073] Table 1: Comparison of stability test results for samples from different examples (comparative examples)

[0074]

[0075] The present invention has been illustrated with the above embodiments to explain the detailed preparation method of the present invention. However, the present invention is not limited to the above detailed preparation method, that is, it does not mean that the present invention must rely on the above product and detailed preparation method to be implemented. Those skilled in the art should understand that any improvement to the present invention, or the combination or equivalent substitution of the raw materials of the present invention, falls within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing an europium-doped Cs3MnX5 luminescent body, characterized in that The method comprises the following steps: S1 : dissolving cesium halide, manganese halide, europium halide in a solvent and wet grinding to form a precursor solution; then heating the precursor solution to volatilize the solvent to form a Cs3MnX5 crude product doped with Eu 2+ ; the cesium halide includes cesium bromide, cesium iodide, and combinations thereof; The manganese halide comprises manganese bromide, manganese iodide and combinations thereof; The europium halide comprises europium bromide, europium iodide and combinations thereof; S2, post-treatment: The crude product obtained from S1 was annealed at 140-180 °C for 15-25 min to obtain a Cs3MnX5 luminescent body doped with Eu 2+ .

2. The method of claim 1, wherein the method is characterized by: The solvent in the step S1 comprises water, ethanol and combinations thereof.

3. The method of claim 1, wherein the method is characterized by: The wet milling time in the step S1 is 10-50 min.

4. A method for preparing an europium-doped Cs3MnX5 luminescent body, characterized in that The method comprises the following steps: A1: dissolving the cesium halide, the manganese halide and the europium halide in a solvent and wet milling to form a precursor solution; A2: adsorbing the precursor solution into the pore channel by a micro / mesoporous template to obtain a space-limited luminescent intermediate; A3: The space-limited luminescent body intermediate is placed in a microwave oven, the microwave is turned on, the power is adjusted to 50-100 W, the microwave time is set to 1-8 min, and the precursor solution is reacted in the micro / mesopore template by microwave heating to form a Cs3MnX5 luminescent body doped with Eu 2+ ; The cesium halide comprises cesium bromide, cesium iodide and combinations thereof; The manganese halide comprises manganese bromide, manganese iodide and combinations thereof; The europium halide comprises europium bromide, europium iodide and combinations thereof.

5. The method of claim 4, wherein the method is characterized by: The micro / mesoporous template is a microporous material and / or a mesoporous material; The microporous material is at least one of microporous molecular sieve, microporous silica, microporous titania, microporous alumina, microporous transition metal oxide, microporous sulfide, microporous silicate, microporous aluminate or microporous transition metal nitride; The mesoporous material is at least one of mesoporous molecular sieve, mesoporous silica, mesoporous titania, mesoporous alumina, mesoporous carbon, mesoporous transition metal oxide, mesoporous sulfide, mesoporous silicate, mesoporous aluminate or mesoporous transition metal nitride.

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