A solid-state preparation method for highly stable CsPbBr3 perovskite composite materials protected by SnF2.

Abstract

This invention belongs to the field of composite material preparation technology, specifically relating to a solid-state preparation method for a highly stable CsPbBr3 perovskite composite material protected by SnF2. The method uses PbBr2 as a lead-bromine source and CsBr as a cesium-bromine source, thoroughly mixing SnF2, the cesium-bromine source, and the lead-bromine source with a carrier in a specific ratio. Under room temperature conditions, a preliminary product is obtained through a solid-state synthesis reaction, followed by high-temperature annealing to synthesize the final product, CsPbBr3. The CsPbBr3 composite material provided by this invention is synthesized without solvents, with a simple process suitable for large-scale production. The prepared composite material exhibits both high fluorescence efficiency and excellent water stability, and can be directly used for assembling LED devices and for compounding with commercial red phosphors to prepare white LEDs.

Description

Technical Field

[0001] This invention belongs to the field of composite material preparation technology, specifically relating to a solid-state preparation method of a high-stability CsPbBr3 perovskite composite material based on SnF2 protection. Background Technology

[0002] In recent years, the all-inorganic lead halide perovskite fluorescent material CsPbX3 has become a research hotspot in the field of novel luminescent materials. This material possesses excellent photoelectric properties and has broad application potential in optoelectronic devices. However, it suffers from several core defects, primarily manifested in imperfect surface structure, insufficient internal ionic stability, and poor tolerance to external environments such as water, oxygen, and light. These defects easily lead to photoelectric performance degradation and crystal structure damage, severely limiting its practical application and long-term stability in optoelectronic and display technologies.

[0003] To address the aforementioned shortcomings, introducing protective agents is a common approach. However, existing protective agents on the market all have significant limitations. For example, traditional organic protective agents have limited functionality and poor stability, either affecting photoelectric transmission efficiency or only providing preliminary improvement for surface defects, failing to solve the problems of internal ionic instability and weak resistance to environmental interference. Existing inorganic protective agents also fail to meet the requirements; most can only exert a weak effect on a specific defect, and their compatibility with materials is poor, making successful bonding impossible. Furthermore, this process may introduce new impurities, exacerbating internal defects, making it difficult to comprehensively address issues related to surface, internal structure, and environmental adaptability.

[0004] CN109775749A discloses a Sn-Pb inorganic alloy perovskite thin film and its application in solar cells. The chemical formula of the Sn-Pb inorganic alloy perovskite thin film is CsSn. 1-x PbxI3, where 0 < x < 1. The preparation method of the Sn-Pb inorganic alloy perovskite thin film includes the following steps: dissolving CsI, SnI2, and PbI2 in an organic solvent containing SnF2, stirring and reacting at 50-80℃ for 12-24h, filtering to obtain a perovskite precursor solution, spin-coating the perovskite precursor solution onto a substrate, and heating at 90-120℃ to obtain a Sn-Pb inorganic alloy perovskite thin film. However, the liquid-phase preparation process disclosed in this patent is mainly aimed at the photovoltaic field of solar cells. In the obtained iodine-based tin-lead perovskite thin film, SnF2 only plays a liquid-phase antioxidant role. The preparation process requires both organic solvents and lacks a carrier structure support, resulting in poor material stability and making it impossible to mass-produce phosphor products.

[0005] In summary, the core defects of CsPbX3 perovskite cannot be fully passivated by existing protective agents, making it difficult to meet the requirements of practical applications. There is an urgent need for a new type of protective agent to specifically solve the above problems and achieve its performance optimization and long-term stability. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the existing technology by providing a solid-state preparation method for a highly stable CsPbBr3 perovskite composite material based on SnF2 protection. This method uses stannous fluoride (SnF2) as a protective agent, and without introducing organic components, prepares the initial target product through a two-step solid-state reaction, followed by high-temperature annealing to finally obtain the target product. The addition of the protective agent SnF2 during high-temperature calcination achieves structural stability of the CsPbBr3 fluorescent material. This synthetic route does not require any organic solvents, and the prepared inorganic CsPbBr3 composite material exhibits both excellent water stability and high fluorescence emission activity. The process is simple, the production cost is low, and it has promising prospects for large-scale mass production.

[0007] The objective of this invention can be achieved through the following technical solutions: A solid-state preparation method for a highly stable CsPbBr3 perovskite composite material protected by SnF2 includes the following steps: (1) SnF2, a lead bromine source, and a first support are mixed and reacted to obtain a first mixture; (2) The bromine-containing cesium source is mixed with the second support and reacted to obtain a second mixture; (3) The first mixture obtained in step (1) is mixed with the second mixture obtained in step (2) to obtain a preliminary product; (4) The preliminary product obtained in step (3) is calcined to obtain CsPbBr3 perovskite composite material.

[0008] Furthermore, in step (1), the bromine-containing lead source is PbBr2; The first carrier is selected from one or more of molecular sieves, silica gel, quartz sand, and PDMS.

[0009] Further, in step (1), the molar ratio of SnF2 to the lead bromine source is (1~4):1; the mass ratio of the first carrier to the lead bromine source is (2~10):1, preferably (3~5):1.

[0010] Furthermore, in step (2), the bromine-containing cesium source is CsBr; The second carrier is selected from one or more of molecular sieves, silica gel, quartz sand, and PDMS.

[0011] Further, in step (2), the mass ratio of the second carrier to the cesium bromine source is (2~10):1, preferably (3~5):1.

[0012] Further, in step (3), the mass ratio of the first mixture to the second mixture is 1:(0.5~1.5).

[0013] Furthermore, in steps (1), (2), and (3), the mixing reaction is selected from at least one of ball milling, grinding, and hot injection. Preferably, ball milling or grinding is used.

[0014] Furthermore, the process parameters of the ball milling method are: rotation speed 200~800rpm, ball-to-material mass ratio (5~20):1, single ball milling time 1~3h, and grinding ball material is zirconium oxide; The process parameters of the grinding method are: rotation speed 100~600rpm, abrasive mass ratio (2~8):1, single grinding time 0.5~2.5h, and grinding media agate or zirconium oxide; The process parameters for the hot injection method are as follows: an oil bath heating platform or a water bath heating platform is used as the heating equipment, the reaction temperature is 60~180℃, water or ethanol is used as the reaction solvent, the concentration of the precursor (the preliminary product in step 3) is 0.05~0.2mol / L, and the heat preservation and ripening time is 5~30min.

[0015] Furthermore, in step (4), the calcination equipment is selected from a tube furnace or a muffle furnace.

[0016] Furthermore, in step (4), the calcination temperature is 400~700℃, the heating rate is 5~10℃ / min, and the calcination time is 0.5~2h.

[0017] Compared with the prior art, the present invention has the following beneficial effects: (1) This invention significantly improves the stability of CsPbBr3 perovskite composite materials by introducing SnF2 as a protective agent, after the raw materials undergo room-temperature solid-state synthesis and high-temperature calcination. The addition of the protective agent not only greatly reduces the corrosion of CsPbBr3 by humidity and water vapor, but also the carrier plays an auxiliary protective role. Specifically, SnF2 releases F during the solid-state reaction. - With Sn 2+ F - With Br - With similar radii, bromine vacancies can be precisely filled, passivating defects. On the other hand, Sn 2+ Inhibit Pb 2+ The disproportionation reduction process, during high-temperature calcination, generates a dense SnO2 thin layer in situ on the grain surface, directly blocking water and oxygen intrusion. Furthermore, the carrier, through its spatial confinement and physical barrier effects, inhibits grain aggregation and delays water and oxygen permeation, achieving a dual improvement in the material's water and oxygen stability and service life.

[0018] (2) The present invention can successfully prepare the target product without the need for or with a small amount of organic ligands or solvents, which is simpler and more economical and suitable for large-scale production. Attached Figure Description

[0019] Figure 1 Photographs of solutions obtained by placing the products of Examples 1-2 and Comparative Examples 1-4 in water and irradiating them with a 365nm ultraviolet lamp; Figure 2 The image shows the XRD pattern of the product obtained in Example 1. Figure 3 The fluorescence emission spectrum of the product obtained in Example 1; Figure 4 The fluorescence emission spectrum of the product obtained in Example 2; Figure 5 The fluorescence emission spectrum of the product obtained in Comparative Example 1 is shown. Figure 6 The fluorescence emission spectrum of the product obtained in Comparative Example 2 is shown. Figure 7 The fluorescence emission spectrum of the product obtained in Comparative Example 3 is shown. Figure 8 The fluorescence emission spectrum of the product obtained in Comparative Example 4 is shown. Detailed Implementation

[0020] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0021] Unless otherwise specified, all raw materials used in this invention are commercially available products.

[0022] Example 1 A solid-state preparation method for a highly stable CsPbBr3 perovskite composite material protected by SnF2, the specific steps of which are as follows: (1) 0.4588g PbBr2 and 0.2940g SnF2 were used as lead bromine source and protective agent, respectively, and 2g silica gel were ball-milled in a ball mill for 2h at a speed of 800 rpm to obtain the first mixture; (2) 0.5320g CsBr and 2g silica gel were ball-milled in a ball mill for 2 h at a speed of 800 rpm to obtain a second mixture; (3) The first mixture obtained by ball milling in step (2) and step (3) is mixed with the second mixture, and ball milled in a ball mill for 2 hours at a speed of 800 rpm. The ball-to-material mass ratio is 10:1, and the grinding ball material is zirconium oxide, to obtain a preliminary sample; (4) The preliminary sample was placed in a muffle furnace and heated to 580°C at a heating rate of 5°C / min. The sample was then calcined for 0.5 h to obtain the target product CsPbBr3@SiO2.

[0023] Example 2 The solid-state preparation method of a high-stability CsPbBr3 perovskite composite material protected by SnF2 is basically the same as that in Example 1, except that the weight of SnF2 used in the first mixture in this example is 0.3920 g.

[0024] Comparative Example 1 A method for preparing a CsPbBr3 perovskite composite material, the specific steps of which are as follows: (1) 0.5320g PbBr2 and 2g silica gel were ball-milled in a ball mill for 2 hours at a speed of 800 rpm to obtain the first mixture; (2) 0.9176g CsBr and 2g silica gel were ball-milled in a ball mill for 2 hours at a speed of 800 rpm to obtain a second mixture; (3) Mix the first mixture obtained by ball milling in steps (1) and (2) with the second mixture, and ball mill in a ball mill for 2 hours at a speed of 800 rpm to obtain a preliminary sample; (4) The preliminary sample was placed in a muffle furnace and heated to 580°C at a heating rate of 5°C / min. The sample was then calcined for 0.5 h to obtain the target product CsPbBr3@SiO2.

[0025] Comparative Example 2 The preparation method of a CsPbBr3 perovskite composite material is basically the same as that of Comparative Example 1, except that 0.5222g of protective agent SnBr2 is added when preparing the first mixture in the comparative example.

[0026] Comparative Example 3 The preparation method of a CsPbBr3 perovskite composite material is basically the same as that of Comparative Example 1, except that 0.1168 g of protective agent MgF2 is added when preparing the first mixture in the comparative example.

[0027] Comparative Example 4 The preparation method of a CsPbBr3 perovskite composite material is basically the same as that of Comparative Example 1, except that the weight of PbBr2 used in the preparation of the first mixture in the comparative example is 0.9176 g.

[0028] The above embodiments and comparative examples are illustrated in photographs of the products obtained in water. Figure 1 As shown, from left to right, they are Examples 1-2 and Comparative Examples 1-4. Figure 1As can be seen, after placing the products in water, Examples 1-2 were light green solutions under 365nm fluorescent light, Comparative Examples 1 and 3 were light blue solutions, Comparative Example 2 was a colorless solution, and Comparative Example 4 was a yellow solution. Examples 1-2 used SnF2 as a protecting agent, which showed better water stability compared to CsPbBr3 synthesized from CsBr and PbBr2 and the addition of other protecting agents. Figure 2 The image shows the XRD pattern of the final product obtained in Example 1. As can be seen from the image, the obtained product corresponds to the CsPbBr3 standard card #18-0364. Figure 3 , 4 The fluorescence emission spectra of the final products of Examples 1-2 are shown. The fluorescence emission peak of Example 1 is the highest (1833), while the fluorescence emission peak of Example 2 is slightly lower (1396). Figure 5-8 Comparing the fluorescence emission spectra of the final products of Comparative Examples 1-4, the fluorescence emission peaks of Comparative Examples 1, 3, and 4 are all below 1000, with Comparative Example 4 having the lowest peak at only 170. Although the final product of Comparative Example 2 has a fluorescence emission peak of 1378, the fluorescence of the obtained product is rapidly quenched in water, indicating extremely poor water stability.

[0029] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A solid-state preparation method for a highly stable CsPbBr3 perovskite composite material protected by SnF2, characterized in that, Includes the following steps: (1) SnF2, a bromine-containing lead source, and a first support are mixed and reacted to obtain a first mixture; (2) The bromine-containing cesium source is mixed with the second support and reacted to obtain a second mixture; (3) The first mixture obtained in step (1) is mixed with the second mixture obtained in step (2) to obtain a preliminary product; (4) The preliminary product obtained in step (3) is calcined to obtain CsPbBr3 perovskite composite material.

2. The solid-state preparation method of a high-stability CsPbBr3 perovskite composite material based on SnF2 protection according to claim 1, characterized in that, In step (1), the bromine-containing lead source is PbBr2; The first carrier is selected from one or more of molecular sieves, silica gel, quartz sand, and PDMS.

3. The solid-state preparation method of a high-stability CsPbBr3 perovskite composite material based on SnF2 protection according to claim 1, characterized in that, In step (1), the molar ratio of SnF2 to the lead bromine source is (1~4):1; the mass ratio of the first carrier to the lead bromine source is (2~10):

1.

4. The solid-state preparation method of a high-stability CsPbBr3 perovskite composite material based on SnF2 protection according to claim 1, characterized in that, In step (2), the bromine-containing cesium source is CsBr; The second carrier is selected from one or more of molecular sieves, silica gel, quartz sand, and PDMS.

5. The solid-state preparation method of a high-stability CsPbBr3 perovskite composite material based on SnF2 protection according to claim 1, characterized in that, In step (2), the mass ratio of the second carrier to the bromine-containing cesium source is (2~10):

1.

6. The solid-state preparation method of a high-stability CsPbBr3 perovskite composite material based on SnF2 protection according to claim 1, characterized in that, In step (3), the mass ratio of the first mixture to the second mixture is 1:(0.5~1.5).

7. The solid-state preparation method of a high-stability CsPbBr3 perovskite composite material based on SnF2 protection according to claim 1, characterized in that, In steps (1), (2) and (3), the mixing reaction is selected from at least one of ball milling and grinding.

8. The solid-state preparation method of a high-stability CsPbBr3 perovskite composite material based on SnF2 protection according to claim 7, characterized in that, The process parameters for the ball milling method are: rotation speed 200~800rpm, ball-to-material mass ratio (5~20):1, single ball milling time 1~3h, and grinding ball material is zirconium oxide; The process parameters of the grinding method are: rotation speed 100~600rpm, abrasive mass ratio of (2~8):1, single grinding time of 0.5~2.5h, and grinding media of agate or zirconium oxide.

9. The solid-state preparation method of a high-stability CsPbBr3 perovskite composite material based on SnF2 protection according to claim 1, characterized in that, In step (4), the calcination equipment is selected from a tube furnace or a muffle furnace.

10. The solid-state preparation method of a high-stability CsPbBr3 perovskite composite material based on SnF2 protection according to claim 1, characterized in that, In step (4), the calcination temperature is 400~700℃, the heating rate is 5~10℃ / min, and the calcination time is 0.5~2h.

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