La-Ce-Eu composite sensitized rare earth light conversion functional material, preparation method and application thereof

Abstract

The present invention discloses a lanthanum-cerium-europium composite sensitized rare earth light-converting functional material, a preparation method therefor and an application thereof, and belongs to the technical field of rare earth functional materials; the chemical composition of the light-converting functional material is (Eu 0.1 Ce x La （0.9‑x） )(TTA)₃(Phen), wherein 0 < x ≤ 0.1, preferably x = 0.001. In the present invention, Eu 3+ serves as a luminescence center, Ce 3+ serves as a sensitizer, which efficiently absorbs ultraviolet light through allowed 4f-5d transition and resonantly transfers energy to Eu 3+ , La 3+ serves as an inert matrix for increasing the ion spacing of Eu 3+ ions to inhibit concentration quenching, and TTA and Phen form a dual-ligand system to form an eight-coordination structure so as to improve thermal stability. The present invention solves the technical problems of weak ultraviolet absorption, serious concentration quenching, poor thermal stability and poor compatibility with a matrix in existing light-converting functional materials, and can be used in the fields of optical devices, luminescence labeling and agricultural light-converting films.

Description

Technical Field

[0001] This invention belongs to the field of rare earth functional materials application technology, specifically a lanthanum-cerium-europium composite sensitized rare earth optical conversion functional material, its preparation method and its application. Background Technology

[0002] Rare earth organic complexes, due to their unique 4f electron shell structure, possess advantages such as high luminescence efficiency, good color purity, tunable emission wavelength, and high light absorption and energy transfer efficiency, making them an important research direction in the field of rare earth ion-activated luminescent materials. Europium (Eu) is a particularly important example. 3+ Ion-activated organic complex luminescent materials have characteristics such as high color purity, sharp emission peaks, and good stability, and have been widely used in optical devices, luminescent markings, and other fields.

[0003] In the field of luminescent materials, achieving efficient light conversion has always been a research hotspot. Europium ion-activated organic complexes can absorb ultraviolet light and emit characteristic red light, showing potential value in light conversion applications. However, currently synthesized europium ion-activated organic complexes generally suffer from the following technical problems: First, the absorption capacity of a single europium ion for ultraviolet light is weak, mainly relying on ligands to absorb energy, resulting in limited light conversion efficiency; Second, when the europium ion concentration is high, the interionic distance decreases, easily leading to cross-relaxation and concentration quenching, thus reducing luminescence intensity; Third, existing europium complexes are susceptible to environmental factors such as moisture and oxygen during long-term use, exhibiting insufficient photostability and thermal stability; Fourth, the emission spectrum often contains components that do not match the absorption band, causing energy loss. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a lanthanum-cerium-europium composite sensitized rare earth optical conversion functional material, its preparation method, and its applications, as detailed below: A lanthanum-cerium-europium composite sensitized rare earth optical conversion functional material, wherein the chemical composition of the optical conversion functional material is: (Eu... 0.1 Ce x La （0.9-x） (TTA)3 (Phen); x is the molar ratio of Ce, and 0 <x≤0.1; The Eu is Eu 3+ It exists in form, serving as the center of light; The Ce with Ce 3+ It exists in the form of a sensitizer, used to absorb ultraviolet light and transfer energy to Eu, which is the luminescent center. 3+ ; The La is La 3+ It exists in a form that serves as an inert matrix, used to increase Eu. 3+ The interion spacing is used to suppress concentration quenching; The TTA and Phen form a dual-ligand system with Ce 3+ La 3+ Eu 3+ Coordination forms an eight-coordination structure to improve the thermal stability of the light-converting functional material.

[0005] Furthermore, the chemical composition of the light-converting functional material is: (Eu 0.1 Ce 0.001 La 0.899 (TTA)3(Phen), that is, x=0.001.

[0006] Furthermore, the Ce 3+ The 4f-5d allowed transition absorbs ultraviolet light, and the excitation energy is transferred to Eu, which is the luminescent center, through resonant energy transfer. 3+ .

[0007] Furthermore, the TTA and Phen constitute a dual-ligand system, which interacts with Ce. 3+ La 3+ Eu 3+ Coordinating to form an eight-coordinate structure to shield water molecules from Ce 3+ La 3+ Eu 3+ The quenching effect makes the thermal decomposition temperature of the optically convertible functional material higher than 280℃.

[0008] Furthermore, the average particle size of the light-converting functional material is 100-150 nm (preferably 109.3 ± 3.5 nm).

[0009] Furthermore, the thermal decomposition initiation temperature of the light-converting functional material is 289°C, and the T-5% temperature (the temperature at which the sample mass loss reaches 5% in TGA) is greater than 250°C.

[0010] Furthermore, TTA is 2-thiophenecarboxyltrifluoroacetone, and Phen is 1,10-phenanthroline.

[0011] Furthermore, it includes the following steps: Step 1: Weigh out lanthanum salt, cerium salt, europium salt, TTA, and Phen, wherein TTA and Ce are mixed. 3+ La 3+ Eu 3+ The total molar ratio is 3:1, Phen and Ce 3+ La 3+ Eu 3+ The total molar ratio is 1:1; Step 2: Dissolve TTA and Phen in anhydrous ethanol and stir until completely dissolved to obtain a dual-ligand system solution; Step 3: Dissolve lanthanum salt, cerium salt and europium salt in anhydrous ethanol and stir until completely dissolved to obtain a mixed rare earth salt solution; Step 4: Under stirring conditions, slowly add the mixed rare earth salt solution dropwise to the dual ligand system solution, while adjusting the pH to 6.5-7.5 with an alkaline solution, controlling the reaction temperature at 15-25℃, and the reaction time at 30-50 minutes; Step 5: After the reaction is complete, the precipitate is filtered and washed successively with anhydrous ethanol and anhydrous diethyl ether, and then dried in a vacuum drying oven at 30-50℃ for 10-14 hours to obtain the optically convertible functional material.

[0012] Further, in step one, the lanthanum salt is lanthanum chloride hexahydrate (Lacl3·6H2O), the cerium salt is cerium chloride hexahydrate (Cecl3·6H2O), and the europium salt is europium chloride hexahydrate (Eucl3·6H2O).

[0013] Furthermore, in step four, the stirring conditions are a stirring rate of 600 rpm and a dropping speed of 1-3 drops / second; in step five, the number of washing cycles is 2-4.

[0014] On the other hand, the present invention provides the application of the light-converting functional material in optical devices, luminescent markers, or agricultural light-converting films.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention introduces Ce 3+ As a sensitizer, it utilizes the efficient absorption of ultraviolet light by its 4f-5d allowed transition and transfers the excitation energy to Eu through resonant energy transfer. 3+ The luminescent center makes the red light emission intensity more uniform than that of Eu. 3+ The system performance improved by 20%-50%; experimental data showed that when x=0.001, the luminescence intensity was significantly higher than that without Ce. 3+ The quantum yield of the optical conversion functional material of this invention is 40%-65% under 300nm excitation, which is significantly better than the existing technology. The quantum yield is 34.1% higher.

[0016] 2. This invention uses La 3+ As an inert matrix, by increasing Eu 3+ The average interion distance effectively suppressed cross-relaxation and luminescence quenching caused by excessive concentration. Experiments showed that when Ce... 3+ When the molar ratio x ≥ 0.1, the material exhibits a significant concentration quenching effect; while when x is controlled within the range of 0.001 to 0.01, the material is in the optimal sensitization region. This invention achieves this by precisely controlling Ce. 3+The concentration allows light-converting functional materials to maintain excellent luminescence performance even at high doping concentrations, solving the technical problem of concentration quenching in existing technologies.

[0017] 3. This invention employs the synergistic coordination of TTA and Phen dual ligands with Ce. 3+ La 3+ Eu 3+ A stable eight-coordinate structure is formed, which effectively shields the quenching effect of water molecules on rare earth ions. Thermogravimetric analysis shows that the thermal decomposition temperature of this optical conversion functional material is higher than 280℃, and it has good thermal stability, which can meet the processing and use requirements of conventional optical conversion functional materials.

[0018] 4. The light-converting functional material prepared by this invention is in the form of nano-sized powder with an average particle size of 100-150nm (preferably 109.3±3.5nm). The particle size distribution is concentrated and the dispersion is good. It is easy to blend with plastic matrices such as polyolefins. Agricultural light-converting films are prepared by melt extrusion blow molding process, which solves the technical problem of poor compatibility between existing light-converting agents and matrices.

[0019] 5. The emission spectrum of the light-converting functional material of the present invention is concentrated in the characteristic red light region of 612nm, with good color purity, which is highly matched with the spectrum required for plant photosynthesis, and can effectively improve the light energy utilization efficiency.

[0020] 6. This invention addresses the problem of existing rare earth complexes being susceptible to luminescence quenching and poor stability due to water molecule attack. It provides a TTA and Phen dual-ligand system, in which the oxygen atom of TTA and the nitrogen atom of Phen are successfully coordinated with rare earth ions, forming a stable O-RE-N eight-coordinate chelate structure. This effectively shields the rare earth ions from contact and vibrational quenching by external water molecules, enabling them to withstand the high-temperature environment of plastic melting and processing, thus ensuring the luminescence performance and service life of the material in actual production and application. Attached Figure Description

[0021] Figure 1 The emission spectra of Examples 1-7 and Comparative Examples 1 and 2 are shown in comparison.

[0022] Figure 2 The emission spectra of Comparative Example 1, Comparative Example 2 and Example 7 are compared.

[0023] Figure 3 This is a particle size distribution diagram of the light-converting functional material in Example 7.

[0024] Figure 4 The image shows the excitation spectrum of the optically convertible functional material in Example 7, where A is the complete excitation spectrum and B is a magnified view of the area within the red box of A.

[0025] Figure 5 This is a scanning electron microscope image of the light-converting functional material of Example 7.

[0026] Figure 6 This is a scanning electron microscope image of the optical conversion functional material in Comparative Example 1.

[0027] Figure 7 This is a scanning electron microscope image of the optical conversion functional material in Comparative Example 2.

[0028] Figure 8 This is a SEM image showing the selected EDS spot scan analysis points on the surface of the light-converting functional material in Example 7.

[0029] Figure 9 The image shows the EDS spectrum of the Spectrum 6 site on the surface of the light-converting functional material in Example 7.

[0030] Figure 10 The image shows the EDS spectrum of the Spectrum 7 site on the surface of the light-converting functional material in Example 7.

[0031] Figure 11 The image shows the EDS spectrum of the Spectrum 8 site on the surface of the light-converting functional material in Example 7.

[0032] Figure 12 Thermogravimetric analysis curve of the light-converting functional material in Example 7.

[0033] Figure 13 The differential thermogravimetric curve is shown for the light-converting functional material of Example 7.

[0034] Figure 14 This is a secondary electron morphology image of the light-converting functional material of Example 7 within a 5μm × 5μm field of view.

[0035] Figure 15 This is a layered mapping image of the EDS elements corresponding to the light-converting functional material in Example 7.

[0036] Figure 16 This is a single-element EDS mapping distribution image of the light-converting functional material in Example 7.

[0037] Figure 17 The image shows the EDS surface scan total spectrum of the light-converting functional material in Example 7.

[0038] Figure 18 The infrared spectra of the light-converting functional materials of Example 7, Comparative Example 3, and Comparative Example 4 are compared. Detailed Implementation

[0039] The lanthanum chloride hexahydrate (Lacl3·6H2O), cerium chloride hexahydrate (Cecl3·6H2O), europium chloride hexahydrate (Eucl3·6H2O), 2-thiophenecarboxyltrifluoroacetone (TTA), and 1,10-phenanthroline (Phen) used in the following examples were all commercially available analytical grade.

[0040] Example 1 A lanthanum-cerium-europium composite sensitized rare earth optical conversion functional material is disclosed. The composition of this material is: Eu:Ce:La:TTA:Phen in a ratio of 0.1:0.1:0.8:3:1, abbreviated as Eu:Ce:La:TTA:Phen 0.1:0.1:0.8:3:1, or simply (Eu:Ce:La:TTA:Phen 0.1:0.1:0.8:3:1). 0.1 Ce 0.1 La 0.8 (TTA)3(Phen).

[0041] The preparation method is as follows: Step 1: Weigh out lanthanum chloride hexahydrate (Lacl3·6H2O), cerium chloride hexahydrate (Cecl3·6H2O), europium chloride hexahydrate (Eucl3·6H2O), 2-thiophenecarboxyltrifluoroacetone and 1,10-phenanthroline according to the composition ratio, wherein the molar ratio of 2-thiophenecarboxyltrifluoroacetone to the total amount of rare earth ions is 3:1, and the molar ratio of 1,10-phenanthroline to the total amount of rare earth ions is 1:1. Step 2: Dissolve 2-thiophenecarboxyltrifluoroacetone and 1,10-phenanthroline in anhydrous ethanol and stir until completely dissolved to obtain a ligand solution; Step 3: Dissolve lanthanum chloride hexahydrate (Lacl3·6H2O), cerium chloride hexahydrate (Cecl3·6H2O), and europium chloride hexahydrate (Eucl3·6H2O) in anhydrous ethanol and stir until completely dissolved to obtain a mixed rare earth salt solution. Step 4: Under stirring conditions (stirring speed of 600 rpm), slowly add the mixed rare earth salt solution dropwise to the ligand solution (dropping rate of 1-3 drops / second), while adjusting the pH to 6.5-7.5 with an alkaline solution, controlling the reaction temperature at 20℃, and the reaction time at 40 minutes. Step 5: After the reaction is complete, the precipitate is filtered and washed 2-4 times with anhydrous ethanol and anhydrous diethyl ether, and then dried in a vacuum drying oven at 40°C for 12 hours to obtain lanthanum-cerium-europium composite sensitized rare earth optical conversion functional material.

[0042] Example 2 A lanthanum-cerium-europium composite sensitized rare earth optical conversion functional material is disclosed. The composition of this material is: Eu:Ce:La:TTA:Phen in a ratio of 0.1:0.05:0.85:3:1, abbreviated as (Eu:Ce:La:TTA:Phen). 0.1Ce 0.05 La 0.85 (TTA)3(Phen).

[0043] The preparation method is as follows: Step 1: Weigh out lanthanum chloride hexahydrate (Lacl3·6H2O), cerium chloride hexahydrate (Cecl3·6H2O), europium chloride hexahydrate (Eucl3·6H2O), 2-thiophenecarboxyltrifluoroacetone and 1,10-phenanthroline according to the composition ratio, wherein the molar ratio of 2-thiophenecarboxyltrifluoroacetone to the total amount of rare earth ions is 3:1, and the molar ratio of 1,10-phenanthroline to the total amount of rare earth ions is 1:1. Step 2: Dissolve 2-thiophenecarboxyltrifluoroacetone and 1,10-phenanthroline in anhydrous ethanol and stir until completely dissolved to obtain a ligand solution; Step 3: Dissolve lanthanum chloride hexahydrate (Lacl3·6H2O), cerium chloride hexahydrate (Cecl3·6H2O), and europium chloride hexahydrate (Eucl3·6H2O) in anhydrous ethanol and stir until completely dissolved to obtain a mixed rare earth salt solution. Step 4: Under stirring conditions (stirring speed of 600 rpm), slowly add the mixed rare earth salt solution dropwise to the ligand solution (dropping rate of 1-3 drops / second), while adjusting the pH to 6.5-7.5 with an alkaline solution, controlling the reaction temperature at 20℃, and the reaction time at 40 minutes. Step 5: After the reaction is complete, the precipitate is filtered and washed 2-4 times with anhydrous ethanol and anhydrous diethyl ether, and then dried in a vacuum drying oven at 40°C for 12 hours to obtain lanthanum-cerium-europium composite sensitized rare earth optical conversion functional material.

[0044] Example 3 A lanthanum-cerium-europium composite sensitized rare earth optical conversion functional material is disclosed. The composition of this material is: Eu:Ce:La:TTA:Phen in a ratio of 0.1:0.01:0.89:3:1, abbreviated as (Eu:Ce:La:TTA:Phen). 0.1 Ce 0.01 La 0.89 (TTA)3(Phen).

[0045] The preparation method is as follows: Step 1: Weigh out lanthanum chloride hexahydrate (Lacl3·6H2O), cerium chloride hexahydrate (Cecl3·6H2O), europium chloride hexahydrate (Eucl3·6H2O), 2-thiophenecarboxyltrifluoroacetone and 1,10-phenanthroline according to the composition ratio, wherein the molar ratio of 2-thiophenecarboxyltrifluoroacetone to the total amount of rare earth ions is 3:1, and the molar ratio of 1,10-phenanthroline to the total amount of rare earth ions is 1:1. Step 2: Dissolve 2-thiophenecarboxyltrifluoroacetone and 1,10-phenanthroline in anhydrous ethanol and stir until completely dissolved to obtain a ligand solution; Step 3: Dissolve lanthanum chloride hexahydrate (Lacl3·6H2O), cerium chloride hexahydrate (Cecl3·6H2O), and europium chloride hexahydrate (Eucl3·6H2O) in anhydrous ethanol and stir until completely dissolved to obtain a mixed rare earth salt solution. Step 4: Under stirring conditions (stirring speed of 600 rpm), slowly add the mixed rare earth salt solution dropwise to the ligand solution (dropping rate of 1-3 drops / second), while adjusting the pH to 6.5-7.5 with an alkaline solution, controlling the reaction temperature at 20℃, and the reaction time at 40 minutes. Step 5: After the reaction is complete, the precipitate is filtered and washed 2-4 times with anhydrous ethanol and anhydrous diethyl ether, and then dried in a vacuum drying oven at 40°C for 12 hours to obtain lanthanum-cerium-europium composite sensitized rare earth optical conversion functional material.

[0046] Example 4 A lanthanum-cerium-europium composite sensitized rare earth optical conversion functional material is disclosed. The composition of this material is: Eu:Ce:La:TTA:Phen in a ratio of 0.1:0.005:0.895:3:1, abbreviated as (Eu:Ce:La:TTA:Phen). 0.1 Ce 0.005 La 0.895 (TTA)3(Phen).

[0047] The preparation method is as follows: Step 1: Weigh out lanthanum chloride hexahydrate (Lacl3·6H2O), cerium chloride hexahydrate (Cecl3·6H2O), europium chloride hexahydrate (Eucl3·6H2O), 2-thiophenecarboxyltrifluoroacetone and 1,10-phenanthroline according to the composition ratio, wherein the molar ratio of 2-thiophenecarboxyltrifluoroacetone to the total amount of rare earth ions is 3:1, and the molar ratio of 1,10-phenanthroline to the total amount of rare earth ions is 1:1. Step 2: Dissolve 2-thiophenecarboxyltrifluoroacetone and 1,10-phenanthroline in anhydrous ethanol and stir until completely dissolved to obtain a ligand solution; Step 3: Dissolve lanthanum chloride hexahydrate (Lacl3·6H2O), cerium chloride hexahydrate (Cecl3·6H2O), and europium chloride hexahydrate (Eucl3·6H2O) in anhydrous ethanol and stir until completely dissolved to obtain a mixed rare earth salt solution. Step 4: Under stirring conditions (stirring speed of 600 rpm), slowly add the mixed rare earth salt solution dropwise to the ligand solution (dropping rate of 1-3 drops / second), while adjusting the pH to 6.5-7.5 with an alkaline solution, controlling the reaction temperature at 20℃, and the reaction time at 40 minutes. Step 5: After the reaction is complete, the precipitate is filtered and washed 2-4 times with anhydrous ethanol and anhydrous diethyl ether, and then dried in a vacuum drying oven at 40°C for 12 hours to obtain lanthanum-cerium-europium composite sensitized rare earth optical conversion functional material.

[0048] Example 5 A lanthanum-cerium-europium composite sensitized rare earth optical conversion functional material is disclosed. The composition of this material is: Eu:Ce:La:TTA:Phen in a ratio of 0.1:0.003:0.897:3:1, abbreviated as (Eu:Ce:La:TTA:Phen). 0.1 Ce 0.003 La 0.897 (TTA)3 (Phen) The preparation method is as follows: Step 1: Weigh out lanthanum chloride hexahydrate (Lacl3·6H2O), cerium chloride hexahydrate (Cecl3·6H2O), europium chloride hexahydrate (Eucl3·6H2O), 2-thiophenecarboxyltrifluoroacetone and 1,10-phenanthroline according to the composition ratio, wherein the molar ratio of 2-thiophenecarboxyltrifluoroacetone to the total amount of rare earth ions is 3:1, and the molar ratio of 1,10-phenanthroline to the total amount of rare earth ions is 1:1. Step 2: Dissolve 2-thiophenecarboxyltrifluoroacetone and 1,10-phenanthroline in anhydrous ethanol and stir until completely dissolved to obtain a ligand solution; Step 3: Dissolve lanthanum chloride hexahydrate (Lacl3·6H2O), cerium chloride hexahydrate (Cecl3·6H2O), and europium chloride hexahydrate (Eucl3·6H2O) in anhydrous ethanol and stir until completely dissolved to obtain a mixed rare earth salt solution. Step 4: Under stirring conditions (stirring speed of 600 rpm), slowly add the mixed rare earth salt solution dropwise to the ligand solution (dropping rate of 1-3 drops / second), while adjusting the pH to 6.5-7.5 with an alkaline solution, controlling the reaction temperature at 20℃, and the reaction time at 40 minutes. Step 5: After the reaction is complete, the precipitate is filtered and washed 2-4 times with anhydrous ethanol and anhydrous diethyl ether, and then dried in a vacuum drying oven at 40°C for 12 hours to obtain lanthanum-cerium-europium composite sensitized rare earth optical conversion functional material.

[0049] Example 6 A lanthanum-cerium-europium composite sensitized rare earth optical conversion functional material is disclosed. The composition of this material is: Eu:Ce:La:TTA:Phen in a ratio of 0.1:0.002:0.898:3:1, abbreviated as (Eu:Ce:La:TTA:Phen). 0.1 Ce 0.002 La 0.898 (TTA)3(Phen).

[0050] The preparation method is as follows: Step 1: Weigh out lanthanum chloride hexahydrate (Lacl3·6H2O), cerium chloride hexahydrate (Cecl3·6H2O), europium chloride hexahydrate (Eucl3·6H2O), 2-thiophenecarboxyltrifluoroacetone and 1,10-phenanthroline according to the composition ratio, wherein the molar ratio of 2-thiophenecarboxyltrifluoroacetone to the total amount of rare earth ions is 3:1, and the molar ratio of 1,10-phenanthroline to the total amount of rare earth ions is 1:1. Step 2: Dissolve 2-thiophenecarboxyltrifluoroacetone and 1,10-phenanthroline in anhydrous ethanol and stir until completely dissolved to obtain a ligand solution; Step 3: Dissolve lanthanum chloride hexahydrate (Lacl3·6H2O), cerium chloride hexahydrate (Cecl3·6H2O), and europium chloride hexahydrate (Eucl3·6H2O) in anhydrous ethanol and stir until completely dissolved to obtain a mixed rare earth salt solution. Step 4: Under stirring conditions (stirring speed of 600 rpm), slowly add the mixed rare earth salt solution dropwise to the ligand solution (dropping rate of 1-3 drops / second), while adjusting the pH to 6.5-7.5 with an alkaline solution, controlling the reaction temperature at 20℃, and the reaction time at 40 minutes. Step 5: After the reaction is complete, the precipitate is filtered and washed 2-4 times with anhydrous ethanol and anhydrous diethyl ether, and then dried in a vacuum drying oven at 40°C for 12 hours to obtain lanthanum-cerium-europium composite sensitized rare earth optical conversion functional material.

[0051] Example 7 A lanthanum-cerium-europium composite sensitized rare earth optical conversion functional material is disclosed. The composition of this material is: Eu:Ce:La:TTA:Phen in a ratio of 0.1:0.001:0.899:3:1, abbreviated as (Eu:Ce:La:TTA:Phen). 0.1 Ce 0.001 La 0.899 (TTA)3(Phen).

[0052] The preparation method is as follows: Step 1: Weigh out lanthanum chloride hexahydrate (Lacl3·6H2O), cerium chloride hexahydrate (Cecl3·6H2O), europium chloride hexahydrate (Eucl3·6H2O), 2-thiophenecarboxyltrifluoroacetone and 1,10-phenanthroline according to the composition ratio, wherein the molar ratio of 2-thiophenecarboxyltrifluoroacetone to the total amount of rare earth ions is 3:1, and the molar ratio of 1,10-phenanthroline to the total amount of rare earth ions is 1:1. Step 2: Dissolve 2-thiophenecarboxyltrifluoroacetone and 1,10-phenanthroline in anhydrous ethanol and stir until completely dissolved to obtain a ligand solution; Step 3: Dissolve lanthanum chloride hexahydrate (Lacl3·6H2O), cerium chloride hexahydrate (Cecl3·6H2O), and europium chloride hexahydrate (Eucl3·6H2O) in anhydrous ethanol and stir until completely dissolved to obtain a mixed rare earth salt solution. Step 4: Under stirring conditions (stirring speed of 600 rpm), slowly add the mixed rare earth salt solution dropwise to the ligand solution (dropping rate of 1-3 drops / second), while adjusting the pH to 6.5-7.5 with an alkaline solution, controlling the reaction temperature at 20℃, and the reaction time at 40 minutes. Step 5: After the reaction is complete, the precipitate is filtered and washed 2-4 times with anhydrous ethanol and anhydrous diethyl ether, and then dried in a vacuum drying oven at 40°C for 12 hours to obtain lanthanum-cerium-europium composite sensitized rare earth optical conversion functional material.

[0053] Comparative Example 1 A lanthanum-cerium-europium composite sensitized rare earth optical conversion functional material is disclosed. The composition of this material is: Eu:Ce:La:TTA:Phen in a ratio of 0.1:0:0.9:3:1, abbreviated as (Eu:Ce:La:TTA:Phen). 0.1 La 0.9 (TTA)3(Phen).

[0054] The preparation method is as follows: Step 1: Weigh out lanthanum chloride hexahydrate (Lacl3·6H2O), cerium chloride hexahydrate (Cecl3·6H2O), europium chloride hexahydrate (Eucl3·6H2O), 2-thiophenecarboxyltrifluoroacetone and 1,10-phenanthroline according to the composition ratio, wherein the molar ratio of 2-thiophenecarboxyltrifluoroacetone to the total amount of rare earth ions is 3:1, and the molar ratio of 1,10-phenanthroline to the total amount of rare earth ions is 1:1. Step 2: Dissolve 2-thiophenecarboxyltrifluoroacetone and 1,10-phenanthroline in anhydrous ethanol and stir until completely dissolved to obtain a ligand solution; Step 3: Dissolve lanthanum chloride hexahydrate (Lacl3·6H2O), cerium chloride hexahydrate (Cecl3·6H2O), and europium chloride hexahydrate (Eucl3·6H2O) in anhydrous ethanol and stir until completely dissolved to obtain a mixed rare earth salt solution. Step 4: Under stirring conditions (stirring speed of 600 rpm), slowly add the mixed rare earth salt solution dropwise to the ligand solution (dropping rate of 1-3 drops / second), while adjusting the pH to 6.5-7.5 with an alkaline solution, controlling the reaction temperature at 20℃, and the reaction time at 40 minutes. Step 5: After the reaction is complete, the precipitate is filtered and washed 2-4 times with anhydrous ethanol and anhydrous diethyl ether, and then dried in a vacuum drying oven at 40°C for 12 hours to obtain lanthanum-cerium-europium composite sensitized rare earth optical conversion functional material.

[0055] Comparative Example 2 A lanthanum-cerium-europium composite sensitized rare earth optical conversion functional material is disclosed. The composition of this material is: Eu:Ce:La:TTA:Phen in a ratio of 0.1:0.2:0.7:3:1, abbreviated as (Eu:Ce:La:TTA:Phen). 0.1 Ce 0.2 La 0.7 (TTA)3(Phen).

[0056] The preparation method is as follows: Step 1: Weigh out lanthanum chloride hexahydrate (Lacl3·6H2O), cerium chloride hexahydrate (Cecl3·6H2O), europium chloride hexahydrate (Eucl3·6H2O), 2-thiophenecarboxyltrifluoroacetone and 1,10-phenanthroline according to the composition ratio, wherein the molar ratio of 2-thiophenecarboxyltrifluoroacetone to the total amount of rare earth ions is 3:1, and the molar ratio of 1,10-phenanthroline to the total amount of rare earth ions is 1:1. Step 2: Dissolve 2-thiophenecarboxyltrifluoroacetone and 1,10-phenanthroline in anhydrous ethanol and stir until completely dissolved to obtain a ligand solution; Step 3: Dissolve lanthanum chloride hexahydrate (Lacl3·6H2O), cerium chloride hexahydrate (Cecl3·6H2O), and europium chloride hexahydrate (Eucl3·6H2O) in anhydrous ethanol and stir until completely dissolved to obtain a mixed rare earth salt solution. Step 4: Under stirring conditions (stirring speed of 600 rpm), slowly add the mixed rare earth salt solution dropwise to the ligand solution (dropping rate of 1-3 drops / second), while adjusting the pH to 6.5-7.5 with an alkaline solution, controlling the reaction temperature at 20℃, and the reaction time at 40 minutes. Step 5: After the reaction is complete, the precipitate is filtered and washed 2-4 times with anhydrous ethanol and anhydrous diethyl ether, and then dried in a vacuum drying oven at 40°C for 12 hours to obtain lanthanum-cerium-europium composite sensitized rare earth optical conversion functional material.

[0057] Comparative Example 3 A lanthanum-cerium-europium composite sensitized rare earth optical conversion functional material is disclosed. The composition of this material is: Eu:Ce:La:Phen in a ratio of 0.1:0.001:0.899:1, abbreviated as (Eu:Ce:La:Phen). 0.1 Ce 0.001 La 0.899 (Phen), i.e., without the addition of TTA, using only Phen as a ligand, is prepared as follows: Step 1: Weigh out lanthanum chloride hexahydrate (Lacl3·6H2O), cerium chloride hexahydrate (Cecl3·6H2O), europium chloride hexahydrate (Eucl3·6H2O) and 1,10-phenanthroline according to the composition ratio, wherein the molar ratio of 1,10-phenanthroline to the total amount of rare earth ions is 1:1; Step 2: Dissolve 1,10-phenanthroline in anhydrous ethanol and stir until completely dissolved to obtain a ligand solution; Step 3: Dissolve lanthanum chloride hexahydrate (Lacl3·6H2O), cerium chloride hexahydrate (Cecl3·6H2O), and europium chloride hexahydrate (Eucl3·6H2O) in anhydrous ethanol and stir until completely dissolved to obtain a mixed rare earth salt solution. Step 4: Under stirring conditions (stirring speed of 600 rpm), slowly add the mixed rare earth salt solution dropwise to the ligand solution (dropping rate of 1-3 drops / second), while adjusting the pH to 6.5-7.5 with an alkaline solution, controlling the reaction temperature at 20℃, and the reaction time at 40 minutes; Step 5: After the reaction is complete, the precipitate is filtered and washed 2-4 times with anhydrous ethanol and anhydrous diethyl ether, and then dried in a vacuum drying oven at 40°C for 12 hours to obtain lanthanum-cerium-europium composite sensitized rare earth optical conversion functional material.

[0058] Comparative Example 4 A lanthanum-cerium-europium composite sensitized rare earth optical conversion functional material is disclosed. The composition of this material is: Eu:Ce:La:TTA in a ratio of 0.1:0.001:0.899:3, abbreviated as (Eu:Ce:La:TTA). 0.1 Ce 0.001 La 0.899 (TTA)3, i.e., without the addition of Phen, using only TTA as a ligand, is prepared as follows: Step 1: Weigh out lanthanum chloride hexahydrate (Lacl3·6H2O), cerium chloride hexahydrate (Cecl3·6H2O), europium chloride hexahydrate (Eucl3·6H2O), and 2-thiophenecarboxylic acid trifluoroacetone according to the composition ratio, wherein the molar ratio of 2-thiophenecarboxylic acid trifluoroacetone to the total amount of rare earth ions is 3:1; Step 2: Dissolve 2-thiophenecarboxyltrifluoroacetone in anhydrous ethanol and stir until completely dissolved to obtain a ligand solution; Step 3: Dissolve lanthanum chloride hexahydrate (Lacl3·6H2O), cerium chloride hexahydrate (Cecl3·6H2O), and europium chloride hexahydrate (Eucl3·6H2O) in anhydrous ethanol and stir until completely dissolved to obtain a mixed rare earth salt solution. Step 4: Under stirring conditions (stirring speed of 600 rpm), slowly add the mixed rare earth salt solution dropwise to the ligand solution (dropping rate of 1-3 drops / second), while adjusting the pH to 6.5-7.5 with an alkaline solution, controlling the reaction temperature at 20℃, and the reaction time at 40 minutes. Step 5: After the reaction is complete, the precipitate is filtered and washed 2-4 times with anhydrous ethanol and anhydrous diethyl ether, and then dried in a vacuum drying oven at 40°C for 12 hours to obtain lanthanum-cerium-europium composite sensitized rare earth optical conversion functional material.

[0059] Experimental Section Experiment 1 Different Ce 3+ Effect of doping concentration on emission spectrum and luminescence intensity of optically convertible functional materials The light-converting functional materials from Examples 1-7 and Comparative Examples 1 and 2 were used to perform emission spectra measurements on the nine groups of samples using a fluorescence spectrometer. The excitation wavelength was 300 nm, the scanning range was 550 nm-700 nm, and the detector was a photomultiplier tube (PMT). Each sample was tested three times under the same conditions, and the average spectrum was used for comparative analysis. Using the emission peak intensity of the sample in Comparative Example 1 as a baseline (100%), the percentage increase in relative luminescence intensity for each example was calculated and compared with Eu. 3+ Characteristic red light intensity at 612 nm.

[0060] Figure 1 The emission spectra of nine groups of samples were compared. The results show that Ce 3+ At higher concentrations (Example 2), the luminescence intensity decreased significantly, exhibiting a marked concentration quench; with increasing Ce... 3+ The intensity decreased, but gradually increased; the intensity was highest in Example 7 (Ce=0.001), which was 34.1% higher than the control group. Figure 2 A close comparison of Comparative Examples 1 and 2 with Example 7 further confirms the presence of trace amounts of Ce. 3+ Optimal sensitization, high Ce 3+ Sudden death is severe, La 3+ The optimal ratio for effectively diluting the rare earth ion spacing and suppressing quenching is Eu:Ce:La = 0.1:0.001:0.899 (Example 7).

[0061] Experiment 2 Characterization of particle size distribution and dispersibility of optically convertible functional materials An appropriate amount of the sample from Example 7 was dispersed in anhydrous ethanol and ultrasonically dispersed until uniform. Particle size was then measured using a dynamic light scattering particle size analyzer at 25°C. Each sample was tested three times, and the average value was taken. Results are shown below. Figure 3 As can be seen from the figure (Eu 0.1 Ce 0.001 La 0.899The average particle size of (TTA)3 (Phen) is 109.3±3.5nm, with a concentrated particle size distribution (main peak at 105.7nm) and extremely low content of large particles (<1%), which proves that the material has good dispersibility, no obvious agglomeration, and excellent repeatability of the synthesis process.

[0062] Experiment 3: Analysis of the excitation spectrum and energy transfer mechanism of optically functional materials The excitation spectrum of the sample in Example 7 was measured using a fluorescence spectrometer at a monitoring wavelength of 612 nm (Eu). 3+ Characteristic emission wavelength), scanning range: 250 nm-500 nm; detector: photomultiplier tube (PMT); each sample was tested three times under the same conditions, and the average spectrum was analyzed. Results are shown below. Figure 4 (A is the complete excitation spectrum, B is a magnified view of the area within the red box of A), (Eu 0.1 Ce 0.001 La 0.899 The excitation spectrum of (TTA)3(Phen) exhibits a strong and broad peak at 300 nm, which is Ce 3+ The superposition of 4f-5d allowed transitions and ligand TTA absorption indicates that Ce 3+ It acts as a sensitizer. Ce 3+ The 4f-5d allowed transition efficiently absorbs ultraviolet light, and then the excitation energy is transferred to Eu via resonant energy transfer. 3+ The luminescent center exhibits a weak peak at 395 nm, which is the Eu peak. 3+ The direct excitation peak is present, but its intensity is weak, indicating that the ultraviolet absorption of this material mainly relies on Ce. 3+ Sensitization and ligand uptake, rather than Eu 3+ The direct excitation of Ce. The presence of a strong, broad peak at 300 nm confirms that Ce... 3+ It effectively broadens the ultraviolet absorption spectrum of the material, enabling the material to utilize ultraviolet light energy more efficiently.

[0063] Experiment 4 Different Ce 3+ Effect of doping concentration on the microstructure of optically convertible functional materials Samples from Comparative Example 1, Comparative Example 2, and Example 7 were fixed onto conductive adhesive, sputtered with gold, and their microstructure was observed using a scanning electron microscope (SEM). The results are shown in the figure. Figure 5-7 , Figure 5 This is the SEM image of Example 7. Figure 6 This is the SEM image for Comparative Example 1. Figure 7 This is the SEM image of Comparative Example 2.

[0064] As shown in the figure, the optically convertible functional material particles provided in Example 7 are uniformly strip-shaped, evenly distributed, and free of impurities. Under this ratio, the rare earth elements and organic matrix react fully. The strip-shaped particles have a smooth surface without pores, and the surface has evenly distributed small white particles, indicating that when Ce... 3+ When the molar ratio is 0.001, the reaction degree between rare earth and organic matrix is ​​moderate, and the material morphology is regular.

[0065] The SEM image of the sample in Comparative Example 1 shows that the optically convertible material is randomly distributed as spherical and strip-shaped particles. Under this formulation, due to the absence of Ce... 3+ When added, the rare earth elements did not fully react with the organic matrix, resulting in a large number of C and H spherical particles. These strip-shaped particles also exhibited micropores and an uneven surface, indicating a deficiency of Ce. 3+ At that time, the reaction was incomplete, and the material morphology was uneven.

[0066] The SEM images of the sample in Comparative Example 2 show that the light-converting functional material is in the form of spherical particles, strip-shaped particles and ablation strip-shaped particles. Under this ratio, the rare earth and organic matrix react excessively to form ablation strip-shaped particles. The surface of the strip-shaped particles has obvious pores and the edges are serrated. The addition of excessive Ce element leads to concentration quenching, causing the organic matrix to ablate and the edges to show uneven spherical particles.

[0067] In conclusion, Ce 3+ The doping concentration has a decisive influence on the microstructure of optically convertible functional materials; only when Ce... 3+ When the concentration is appropriate (Example 7, x=0.001), uniform strip-shaped particles with regular morphology can be obtained. The surface is smooth and without pores, and the white small particles are evenly distributed, indicating that the rare earth and organic matrix react fully under this ratio, which is the optimal composition.

[0068] Experiment 5 Verification of Surface Element Content and Ce Adhesion in Optical Conversion Functional Materials Sample from Example 7 (Eu) was selected. 0.1 Ce 0.001 La 0.899 EDS point scan analysis was performed on three different test points on the (TTA)3 (Phen) surface, denoted as Spectrum6, Spectrum7, and Spectrum8 respectively. Figure 8 Spectrum 6 and Spectrum 7 correspond to white microparticles, while Spectrum 8 corresponds to a blank area. Elemental composition data were collected from three test points: Spectrum 6, Spectrum 7, and Spectrum 8, and the differences in elemental content at different locations were compared. The EDS spectrum of Spectrum 6 is shown below. Figure 9 The EDS elemental analysis results are shown in Table 1; the EDS energy spectrum of Spectrum 7 is shown in Table 1. Figure 10The EDS elemental analysis results are shown in Table 2; the EDS energy spectrum of Spectrum 8 is shown in Table 2. Figure 11 The EDS elemental analysis results are shown in Table 3.

[0069] from Figure 9-11 As shown in Tables 1-3, the Ce content in the white microparticles (Spectrum 6 and Spectrum 7) was 1.94 wt% and 2.35 wt%, respectively, both significantly higher than the Ce content in the blank area (Spectrum 8) (1.37 wt%). Meanwhile, the La content in Spectrum 6 and Spectrum 7 was 27.06 wt% and 30.18 wt%, respectively, and the Eu content was 1.98 wt% and 3.90 wt%, respectively, while the La content in Spectrum 8 was 29.30 wt% and the Eu content was 2.59 wt%. These results indicate that the white microparticles are Ce-enriched regions. 3+ Successfully attached to the surface of the organic matrix and uniformly distributed in the form of white particles; La and Eu were detected at all sites and were relatively uniformly distributed, confirming that the three rare earth elements were successfully incorporated into the organic matrix.

[0070] Table 1. EDS elemental analysis results of Spectrum 6

[0071] Table 2. EDS elemental analysis results of Spectrum 7

[0072] Table 3. EDS elemental analysis results of Spectrum 8

[0073] Experiment 6 Surface elemental distribution of optically convertible functional materials Sample from Example 7 (Eu) was selected. 0.1 Ce 0.001 La 0.899 (TTA)3 (Phen), before testing, the sample was dispersed in anhydrous ethanol and ultrasonically treated for 5 minutes to achieve uniform dispersion; then the suspension was dropped onto the silicon wafer substrate, and after the solvent evaporated naturally, the sample surface was sprayed with gold for conductive treatment.

[0074] The tests were conducted using a Czech-made TESCAN MIRA LMS field emission scanning electron microscope, equipped with a Schottky field emission electron gun and a matching energy dispersive spectroscopy (EDS) spectrometer. Test conditions: accelerating voltage 15 kV, working distance 10 mm, probe current 5-10 nA, high vacuum mode. Microscopic images of the samples were acquired in secondary electron (SE) mode to observe particle size, dispersion, and aggregation. A typical region (5 μm × 5 μm) was selected for simultaneous EDS point and area scanning (mapping) analysis, acquiring distribution images and total spectra of C, O, N, La, Ce, and Eu elements. Single pixel dwell time was 100 μs, and the total count was >5 × 10⁻⁶. 5 Semi-quantitative analysis was performed using standard-free ZAF correction to characterize the elemental composition and distribution uniformity.

[0075] Figure 14 This is a secondary electron (SE) topography image of the sample from Example 7 within a 5μm × 5μm field of view. Figure 15 The mapping image is layered and overlaid on the corresponding EDS elements. From Figure 14 As can be seen, the overall surface of the sample is flat and dense, with no obvious large particle agglomeration, pores or phase separation. Only a few tiny bright spots exist, indicating that the sample is well dispersed on the silicon wafer substrate, without serious agglomeration problems, and the overall microstructure is uniform and stable. Figure 15 In the superposition results, different colors correspond to different element signals. It can be seen from the superposition results that all element signals are uniformly diffused in the field of view, without local element enrichment or obvious segregation. This preliminarily proves that the TTA / Phen dual ligand system has achieved uniform recombination with rare earth ions (La, Ce, Eu).

[0076] To further clarify the distribution of each element, the single-element EDS Mapping images were analyzed separately, and the results are as follows: Figure 16 As shown in the figure, the signals of C, O, and N elements in the organic matrix are continuously and uniformly distributed within the field of view, with no obvious signal loss or local enrichment. This indicates that the organic ligands form a complete and continuous framework structure, providing a stable dispersion environment for rare earth ions. The La element signal has the highest intensity and the most uniform distribution, indicating good matrix phase uniformity. The Ce and Eu element signals are diffusely and uniformly distributed, without local aggregation or segregation. This suggests that the trace dopant ions are uniformly dispersed in the La matrix, effectively avoiding fluorescence quenching effects caused by excessively high local concentrations, thus providing structural assurance for the material's efficient luminescence.

[0077] Figure 17Table 4 shows the EDS surface scan total spectrum of the sample from Example 7, and the corresponding semi-quantitative analysis results are presented in Table 4. As can be seen from Table 4, La is the main component among rare earth elements, with an atomic fraction of 3.43 at%, while Ce and Eu are minor dopant components, with atomic fractions of 0.23 at% and 0.29 at%, respectively. The doping ratio is uniform and controllable. Figure 17 It can be seen that the introduction of La makes the distribution of rare earth elements more uniform and prevents concentration quenching. The absence of impurity peaks indicates high sample purity. The characteristic peaks of Eu, Ce, and La shown in the figure confirm that the rare earth elements have been successfully doped into the matrix. The above results indicate that (Eu... 0.1 Ce 0.001 La 0.899 The uniform distribution and stable composition of the (TTA)3 (Phen) element, along with its excellent structural uniformity, lay the foundation for the stable output of its subsequent optical conversion performance.

[0078] Table 4. Results of EDS surface scan semi-quantitative analysis of sample 7 in Example 7

[0079] Experiment 7 Thermal stability analysis of light-converting functional materials Samples from Example 7 were subjected to TGA testing using a thermogravimetric analyzer. The atmosphere was nitrogen, the heating rate was 10℃ / min, and the testing range was room temperature to 600℃. Recorded parameters included TG (thermogravimetric) curves and DTG (differential thermogravimetric) curves. Each sample was tested three times under the same conditions, and the average thermogravimetric curve was analyzed. The TG curve is shown below. Figure 12 As shown, the sample begins to show significant mass loss at 289℃, which is the main decomposition initiation point; the main decomposition stage is between 289℃ and 348℃, during which mass loss is rapid; above 500℃, the TG curve tends to flatten out, indicating that the decomposition reaction is basically complete. Based on the T-5% temperature (>250℃), the sample exhibits good thermal stability and is suitable for applications in conventional optical conversion functional materials.

[0080] Differential thermogravimetric curve as shown Figure 13 As shown, a distinct decomposition peak appears at 275-280℃, indicating that the decomposition rate is fastest near this temperature. The DTG curve shows that the decomposition process is relatively continuous, without obvious multi-stage decomposition peaks, indicating that the sample composition is relatively homogeneous.

[0081] Experiment 8 Infrared Spectroscopic Verification of the Dual-Coordination Structure Samples from Example 7, Comparative Example 3, and Comparative Example 4 were taken respectively, and their coordination structures were characterized using Fourier transform infrared spectroscopy (FT-IR). The test conditions were as follows: samples were prepared using the KBr pellet method, and the scanning wavenumber range was 4000-50 cm⁻¹. -1 4cm resolution -1 The number of scans was 32.

[0082] The results are as follows Figure 18 As shown, the C=O characteristic peak of sample TTA in Example 7 is from 1651 cm⁻¹. -1 Redshifted to 1602cm -1 Phen's C=N characteristic peak is at 1585 cm⁻¹ -1 Redshifted to 1532cm -1 This indicates that the oxygen atom in TTA and the nitrogen atom in Phen both coordinate with rare earth ions; a fingerprint region of 782 cm⁻¹ appears. -1 711cm -1 The characteristic peaks of the two coordinations confirm the formation of a stable O-RE-N eight-coordination chelate structure; 3622 cm⁻¹ -1 The free hydroxyl peak is significantly weakened, and water molecules are effectively shielded. Based on this, the thermal decomposition initiation temperature of the material of this invention reaches 289℃, and the T-5% temperature exceeds 250℃. Figure 12-13 Its luminescence properties are far superior to those of similar materials in existing technologies, enabling it to withstand the high-temperature environment of plastic melting and processing, thus ensuring the material's luminescent properties and service life in actual production and application.

Claims

1. A lanthanum-cerium-europium composite sensitized rare earth optical conversion functional material, characterized in that, The chemical composition of the light-converting functional material is: (Eu) 0.1 Ce 0.001 La 0.899 (TTA)3(Phen); The Eu is Eu 3+ It exists in form, serving as the center of light; The Ce with Ce 3+ It exists in the form of a sensitizer, used to absorb ultraviolet light and transfer energy to Eu, which is the luminescent center. 3+ ; The La is La 3+ It exists in a form that serves as an inert matrix, used to increase Eu. 3+ The interion spacing is used to suppress concentration quenching; The TTA and Phen form a dual-ligand system with Ce 3+ La 3+ Eu 3+ Coordinating to form an eight-coordinate structure to shield water molecules from Ce 3+ La 3+ Eu 3+ The quenching effect makes the thermal decomposition temperature of the optically convertible functional material higher than 280℃. The TTA is 2-thiophenecarboxyltrifluoroacetone, and Phen is 1,10-phenanthroline.

2. The lanthanum-cerium-europium composite sensitized rare earth optical conversion functional material according to claim 1, characterized in that, The Ce 3+ The 4f-5d allowed transition absorbs ultraviolet light, and the excitation energy is transferred to Eu, which is the luminescent center, through resonant energy transfer. 3 + .

3. The lanthanum-cerium-europium composite sensitized rare earth optical conversion functional material according to claim 1, characterized in that, The average particle size of the optical conversion functional material is 100-150 nm.

4. A method for preparing a lanthanum-cerium-europium composite sensitized rare earth optical conversion functional material according to any one of claims 1 to 3, characterized in that, Includes the following steps: Step 1: Weigh out lanthanum salt, cerium salt, europium salt, TTA, and Phen, wherein TTA and Ce are mixed. 3+ La 3+ Eu 3+ The total molar ratio is 3:1, Phen and Ce 3+ La 3+ Eu 3+ The total molar ratio is 1:1; Step 2: Dissolve TTA and Phen in anhydrous ethanol and stir until completely dissolved to obtain a dual-ligand system solution; Step 3: Dissolve lanthanum salt, cerium salt and europium salt in anhydrous ethanol and stir until completely dissolved to obtain a mixed rare earth salt solution; Step 4: Under stirring conditions, slowly add the mixed rare earth salt solution dropwise to the dual ligand system solution, while adjusting the pH to 6.5-7.5 with an alkaline solution, controlling the reaction temperature at 15-25℃, and the reaction time at 30-50 minutes; Step 5: After the reaction is complete, the precipitate is filtered and washed successively with anhydrous ethanol and anhydrous diethyl ether, and then dried in a vacuum drying oven at 30-50℃ for 10-14 hours to obtain the optically convertible functional material.

5. The preparation method according to claim 4, characterized in that, In step one, the lanthanum salt is lanthanum chloride hexahydrate, the cerium salt is cerium chloride hexahydrate, and the europium salt is europium chloride hexahydrate.

6. The preparation method according to claim 4, characterized in that, In step four, the stirring conditions are a stirring rate of 600 rpm and a dropping rate of 1-3 drops / second; in step five, the washing is performed 2-4 times.

7. The application of the light-converting functional material according to any one of claims 1 to 3 in optical devices, luminescent markers, or agricultural light-converting films.

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