CN110734760A

CN110734760A - rare earth europium composite fluorescent material using sodium acetate as matrix and preparation method thereof

Info

Publication number: CN110734760A
Application number: CN201810798625.5A
Authority: CN
Inventors: 陶栋梁; 金凤; 宋苗苗; 王永忠; 姜广鹏; 陈继堂; 张琳; 崔玉民; 张宏; 李慧泉
Original assignee: Fuyang Normal University
Current assignee: Fuyang Normal University
Priority date: 2018-07-19
Filing date: 2018-07-19
Publication date: 2020-01-31

Abstract

The invention provides rare earth europium composite fluorescent materials with sodium acetate as a matrix and a preparation method thereof, europium ions are used as a luminous body, triphenyl phosphorus oxide (TPPO) and 2-Thenoyl Trifluoroacetone (TTA) are used as organic ligands, sodium acetate is used as the matrix, the europium complex composite fluorescent materials are prepared by reaction under set conditions, and the obtained composite fluorescent materials are characterized.

Description

rare earth europium composite fluorescent material using sodium acetate as matrix and preparation method thereof

Technical Field

The invention relates to the field of fluorescent materials, in particular to a rare earth europium composite fluorescent material taking kinds of sodium acetate as matrixes and a preparation method thereof.

Background

The rare earth elements refer to IIIB group in the periodic table, 21 # element scandium Sc, 39 # element yttrium Y and 57-71 lanthanum La, cerium Ce, praseodymium Pr, neodymium Nd, promethium Pm, samarium Sm, europium Eu, gadolinium Gd, terbium Tb, dysprosium Dy, holmium Ho, erbium Er, thulium Tm, ytterbium Yb, lutetium Lu, and total 17 elements. Rare earth elements containing as a host component, activator, co-activator or dopant are a generic term for rare earth fluorescent materials.

At present, rare earth elements have been widely used in the fields of electronic apparatus, petrochemical industry, metallurgy, machinery, energy, light industry, environmental protection, agriculture and the like, steps are further applied to the application of rare earth elements in the production of fluorescent materials, rare earth metal hydride battery materials, electric light source materials, permanent magnetic materials, hydrogen storage materials, catalytic materials, precise ceramic materials, laser materials, superconducting materials, magnetostrictive materials, magnetic cooling materials, magneto-optical storage materials, optical fiber materials and the like.

The rare earth elements have 4f electron layers with unfilled electron orbitals, 5s and 5p electrons on the outer layers have -determined shielding effects on the 4f electrons, so that the rare earth elements are subjected to a small crystal field, and the J energy level is split due to the fact that the electrons on the 4f electron layers have large spin coupling constants, so that the rare earth complex has rich electron energy levels and has special luminescence performance.

The rare earth complex fluorescent material has the advantages of unique molecular structure, photoluminescence mechanism, strong fluorescence, good monochromaticity and the like, is applied to various fields of industry, agriculture, biology and the like, but has slightly poor light and heat stability, and in recent years, rare earth is gradually taken as strategic resource, so that more and more attention is paid, the price of the rare earth is continuously increased, and the rare earth complex is difficult to recover after being used, so that the application of the rare earth complex in various aspects is greatly limited.

Therefore, there is a need to develop rare earth complex composite fluorescent materials with long fluorescent lifetime and simple preparation method, which can reduce the cost and optimize the fluorescent property of the materials, thereby providing a new solution for people to develop novel efficient luminescent materials.

Disclosure of Invention

The present inventors have conducted intensive studies in order to solve the above problems, and as a result, have found that rare earth europium composite fluorescent materials using sodium acetate as a matrix and a method for preparing the same, europium ions are used as a light-emitting body, triphenyl phosphorus oxide (TPPO) and 2-thenoyltrifluoroacetone (TTA) are used as organic ligands, and sodium acetate is used as a matrix, and the europium complex composite fluorescent materials are prepared by reacting under a set condition, and the obtained composite fluorescent materials are characterized.

The object of the present invention is to provide the following:

, the present invention provides kinds of rare earth fluorescent materials, which are composite fluorescent materials with the maximum absorption wavelength of the ultraviolet-visible spectrum near 340 nm.

The fluorescence intensity of the fluorescent material can reach 2400000CPS, and the quantum yield can reach 29.88%.

The rare earth fluorescent material comprises a rare earth complex and a matrix, wherein the matrix is oxygen-containing inorganic salt, preferably the matrix comprises or more of sodium acetate, potassium acetate, sodium acetate, potassium carbonate, calcium carbonate, sodium bicarbonate and potassium bicarbonate, and more preferably sodium acetate.

The rare earth complex is a double-ligand complex of a rare earth compound, the rare earth compound is a terbium, europium, dysprosium or erbium compound, and the europium compound is preferably selected; more preferably, the europium compound is europium chloride;

the double ligands are th ligands and second ligands, the th ligand is β -diketone comprising acetylacetone, 2-thenoyl trifluoroacetone and acetylsalicylate ions, and the second ligand is phenanthroline or triphenyl phosphorus oxide.

In a second aspect, the present invention also provides a method for preparing the rare earth fluorescent material of , comprising the following steps:

step 1: pretreating a substrate material;

step 2: mixing a ligand and a rare earth compound to obtain a solution;

and step 3: reacting the solution in the step 2 with a matrix substance under set conditions;

and 4, step 4: and carrying out post-treatment to obtain a final product.

Drawings

FIG. 1 shows a UV-Vis spectrum of a sample;

FIG. 2 shows an infrared spectrum of a sample;

figure 3 shows an XRD analysis spectrum of the sample;

FIG. 4 shows a thermogravimetric differential thermal profile of a sample;

FIG. 5 shows a line graph of the average particle size of the sample;

FIG. 6 shows a fluorescence emission spectrum of a sample;

FIG. 7 shows a fluorescence emission refractogram of a sample;

FIG. 8 shows a fluorescence excitation spectrum of a sample;

FIG. 9 shows a plot of fluorescence excitation intensity for a sample;

FIG. 10 shows a plot of the average lifetime of the samples;

fig. 11 shows a quantum yield line graph of the sample.

Detailed Description

The features and advantages of the present invention will become more apparent and appreciated from the following detailed description of the invention.

The present invention is described in detail below.

According to th aspect of the present invention, there are kinds of rare earth fluorescent materials, which are composite fluorescent materials having a maximum absorption wavelength of ultraviolet-visible spectrum in the vicinity of 340 nm.

The fluorescence intensity can reach 2400000CPS, and the quantum yield can reach 29.88%.

The rare earth fluorescent material comprises a rare earth complex and a matrix, wherein the matrix is oxygen-containing inorganic salt, preferably, the matrix comprises or more of sodium acetate, potassium acetate, sodium acetate, potassium carbonate, calcium carbonate, sodium bicarbonate and potassium bicarbonate, and more preferably sodium acetate.

The rare earth complex is a dual-ligand complex of a rare earth compound, the rare earth compound is a terbium, europium, dysprosium or erbium compound, and the europium compound is preferably selected; more preferably, the europium compound is europium chloride;

the double ligands are th ligands and second ligands, the th ligand is β -diketone comprising acetylacetone, 2-thenoyl trifluoroacetone and acetylsalicylate ions, and the second ligand is phenanthroline or triphenyl phosphorus oxide (TPPO).

The interest of people in sensitized emission in rare earth complexes starts in 1942, and Weissman finds that characteristic linear emission of Eu ions occurs after different β -diketone type Eu complexes absorb ultraviolet light.

, the fluorescence of the rare earth europium complex is mainly excited ligand to transfer excited energy to central ion through nonradiative intramolecular energy transfer, the central ion emits characteristic fluorescence, and the luminescence phenomenon of the rare earth ion is called rare earth sensitized luminescence.

β -diketone has strong coordination ability and higher absorption coefficient to rare earth ion, and is an excellent ligand for studying transition of rare earth element, and the rare earth β -diketone complex has high-efficiency energy transfer from the ligand to central ion (especially europium ion, terbium ion and the like), so that the complex has high luminous efficiency.

In order to expand the research range of rare earth organic complexes, materials with better luminescence performance are searched, and multi-ligand systems are researched, such as the introduction of second ligands (such as phosphine-oxygen bond-containing compounds, nitrogen-containing aromatic heterocyclic compounds and the like), wherein the second ligands generate synergistic effect in the luminescence process.

The rare earth organic complex is applied to various fields of industry, agriculture, biology and the like due to the advantages of strong fluorescence, good monochromaticity and the like, but the defects of poor light and thermal stability and high cost limit the practicability of the rare earth organic complex.

Therefore, the present inventors have attempted to add an oxygen-containing inorganic compound sodium acetate matrix as an inner core in order that a relatively stable environment can be provided to the rare earth complex to exhibit its light emitting characteristics, and it is expected that its light emitting performance can be improved and its light and heat stability can be improved.

The inventor researches a europium complex and basic sodium acetate salt composite luminescent material through a large amount of exploration experiments, and characterizes the structure and the performance of the europium complex and the basic sodium acetate salt composite luminescent material;

the inventor surprisingly finds that the fluorescent material compounded by europium complex of TTA (2-thenoyltrifluoroacetone) and TPPO (triphenyl phosphorus oxide) and sodium acetate matrix not only improves the light and heat stability of the europium complex, but also improves the fluorescence performance, including longer fluorescence lifetime and high quantum yield, and also reduces the cost of the fluorescent material.

In the invention, the fluorescence emission intensity of the europium complex composite fluorescent material can reach 2400000cps, the average fluorescence lifetime can reach 0.61ms, and the quantum yield reaches 29.88%.

According to a second aspect of the present invention, there are provided methods for preparing the rare earth fluorescent material, comprising the steps of:

step 1: pretreating a substrate material;

step 2: mixing a ligand and a rare earth compound to obtain a solution;

and 4, step 4: and carrying out post-treatment to obtain a final product.

Step 1, pretreating a substrate substance;

the matrix substance is oxygen-containing inorganic salt and comprises or more of sodium acetate, potassium acetate, sodium acetate, potassium carbonate, calcium carbonate, sodium bicarbonate and potassium bicarbonate, preferably the matrix substance is sodium acetate;

the pretreatment comprises mixing the matrix substance with a dispersing agent, and optionally ultrasonically shaking, wherein the dispersing agent is or more of methanol, ethanol and isopropanol, preferably ethanol, and more preferably absolute ethanol.

In preferred embodiments, the pretreatment further comprises drying the matrix material for 1-3 hours before mixing.

The inventor finds that water can affect the complexation of europium ions and ligands and finally affect the performance of the composite fluorescent material.

In the invention, sodium acetate is used as a matrix and is used as alkali and an inner core, so that the europium complex is adsorbed and/or combined on the surface of the sodium acetate, thereby obtaining the composite fluorescent material.

In the invention, the sodium acetate powder can be obtained by commercial or self-preparation.

In the invention, the particle size of the sodium acetate is 30-100 nm.

Without being bound by any theory, the inventor believes that the fluorescent material obtained by using the nano-scale sodium acetate powder as the basic salt has smaller particle size, and meanwhile, the nano-scale sodium acetate has larger specific surface area and can adsorb and/or combine more rare earth complexes, so that the fluorescence intensity of the product can be increased, and the nano-scale sodium acetate with uniform particle size distribution can obtain the fluorescent material with stable performance of .

In the invention, the pretreatment in the step 1 further comprises adding dried sodium acetate into a dispersing agent for ultrasonic oscillation, wherein the dispersing agent is or more of methanol, ethanol and isopropanol, preferably ethanol, and more preferably absolute ethanol.

The inventor finds that ethanol is used as a dispersing agent, so that the solubility is better, and the favorable temperature can be easily controlled when the composite fluorescent material is prepared.

In the present invention, the amount of ethanol used is not particularly limited, and it is sufficient to dissolve all the raw materials.

In preferred embodiments, sodium acetate and ethanol are mixed and stirred uniformly, and then ultrasonic oscillation is carried out for 30min, so that sodium acetate particles are dispersed more uniformly, and the performance of the finally prepared composite fluorescent material is better.

In the invention, the dosage ratio of sodium acetate to ethanol is 1 g: (5-35) mL.

Step 2, mixing the ligand and the rare earth compound to obtain a solution;

the ligand is a dual ligand, the dual ligand is th ligand and a second ligand, the th ligand is β -diketone (such as 2-thenoyl trifluoroacetone), the second ligand is phenanthroline and triphenyl phosphorus oxide, and the second ligand is triphenyl phosphorus oxide;

preferably, the th ligand is 2-thenoyltrifluoroacetone (TTA) and the second ligand is triphenylphosphine oxide (TPPO) in a molar ratio of (0.5-4.5): 1, more preferably (1-4.0): 1, e.g., 1.5: 1.

In the invention, the molar ratio of TTA to the rare earth compound is (1-5): 1, preferably (2-4): 1, such as 3: 1.

The inventors found that the amount of TTA used as the th ligand is not too low, not too high, and too low, which results in failure to achieve optimum coordination and too high, but rather in deterioration of coordination performance, and therefore, it is preferable that the molar ratio of TTA to the rare earth compound is (2-4): 1, and more preferably 3: 1.

β -diketonesThe conversion between ketone type and enol type in the molecule of the compound endows the compound with a plurality of unique coordination chemical properties, and the compound is also a typical metal chelating agent of types, has a larger light absorption coefficient and a proper conjugated system, can effectively sensitize rare earth ions to emit light after being coordinated with rare earth ions³⁺Form a stable six-membered ring that directly absorbs light energy and efficiently transfers energy.

Eu³⁺In addition to the th ligand, is a polydentate ion, which is a polydentate ion, and the second ligand is usually a neutral ligand.

The neutral ligand influences the photoluminescence efficiency and fluorescence intensity of the europium complex mainly by participating in energy transfer and influencing the life of th excited triplet state of the central ligand, and the introduction of the second ligand into the structure of the luminescent complex can obviously improve the luminescent brightness of the material.

In the invention, the performance of the finally obtained composite fluorescent material can be better by researching the TPPO as the second ligand.

The rare earth compound is europium chloride. The europium chloride used in the present invention is europium chloride hexahydrate.

In the invention, when TTA and TPPO ligands are mixed with the rare earth compound, a solvent is added, wherein the solvent is or more of methanol, ethanol and isopropanol, preferably ethanol, and more preferably absolute ethanol.

In the step 2, the amount of the absolute ethyl alcohol is 0.5g (5-35) mL, the amount of the absolute ethyl alcohol is , the absolute ethyl alcohol is required to be capable of completely dissolving the TTA, the TPPO and the rare earth compound, and the amount of the absolute ethyl alcohol is required to be , the amount of the absolute ethyl alcohol is required to be constant concentration, so that the subsequent reaction is facilitated.

In preferred embodiments, the dual ligand and the rare earth compound are added to the solvent separately and are shaken with ultrasound for 30min to dissolve the dual ligand and the rare earth compound completely.

The inventor believes that the rare earth compound and the double ligands are dissolved more completely and mixed with the double ligands more uniformly by utilizing the mechanical effect, the thermal effect and the cavitation of the ultrasound.

In the invention, the europium trichloride is prepared by the following steps:

step 2-1, dissolving europium oxide in a solvent, and heating to a set temperature;

step 2-2, adding acid into the step 2-1 and reacting;

step 2-3, post-treating to obtain a product;

preferably, the first and second electrodes are formed of a metal,

in step 2-1, the solvent is methanol, ethanol, isopropanol or water, and more preferably water; setting the temperature to be 35-65 ℃; more preferably 40-60 deg.C, such as 40 deg.C;

wherein the mass ratio of the europium oxide to the solvent water is 1: (1.5-4.5);

in the step 2-2, the acid is hydrochloric acid, preferably concentrated hydrochloric acid; and/or adding acid in a dropwise manner;

the inventor finds that europium chloride crystals obtained by controlling constant temperature during hydrochloric acid dripping have higher purity, and finally the prepared rare earth europium composite material has better performance.

In step 2-3, the post-treatment comprises filtration, evaporating and crystallizing the filtrate, and then filtering and collecting crystal products;

the filtering mode is not particularly limited, the reduced pressure suction filtration is adopted in the invention, the obtained filtrate is heated and evaporated for crystallization, the evaporation and crystallization temperature is 85-95 ℃, for example, 95 ℃, the heating is stopped until crystal films appear on the surface of the solution, after the solution is cooled, the reduced pressure suction filtration is carried out, the filtered precipitated crystal is collected and transferred to the filtrate, the evaporation and crystallization operation is continuously carried out on the filtrate until all europium chloride in the solution is separated out, the filter cake is transferred to a small beaker and is placed into a dryer for drying for two or three days at normal temperature, and white solid powder europium chloride hexahydrate is obtained and stored in the dryer for standby.

And 3, reacting the solution obtained in the step 2 with a matrix substance under set conditions.

In preferred embodiments, the mass ratio of sodium acetate to europium chloride hexahydrate is (5-100): 1, preferably (10-90): 1.

The inventor finds that the dosage of the sodium acetate influences the magnitude of the fluorescence intensity and the length of the fluorescence lifetime of the composite fluorescent material. Too much sodium acetate can reduce the performance of the composite fluorescent material; the amount of sodium acetate is too small, and the thermal stability of the composite fluorescent material cannot be well improved, so that the mass ratio of the sodium acetate to the europium chloride is preferably (10-90): 1.

The europium chloride used in the present invention is europium chloride hexahydrate.

In preferred embodiments, the matrix substance of step 1 is added dropwise to the mixed solution of step 3.

The inventor finds that a matrix substance sodium acetate is added into the mixed solution obtained in the step 3 in a dropwise manner, so that the sodium acetate, the rare earth compound and the ligand thereof are uniformly mixed, and the finally obtained rare earth europium complex composite fluorescent material with the sodium acetate as the matrix has better fluorescence performance.

In the step 3, the reaction temperature is 50-95 ℃, preferably 80 ℃, the reflux reaction is carried out, and the reaction time is 1-5 hours, preferably 2-4 hours, such as 2.0 hours.

The inventors have found that the length of the reaction time affects the properties of the final composite fluorescent material. In the present invention, the reaction time is more preferably 2.0 hours. The obtained composite fluorescent material has good fluorescence performance and long fluorescence life.

And 4, carrying out post-treatment to obtain a final product.

The post-treatment comprises cooling to room temperature after the reaction is finished, filtering, drying,

preferably, the drying temperature is 60-110 ℃.

In the present invention, the filtration method is not particularly limited, and any conventional filtration method may be used, and in the present invention, reduced pressure filtration is employed.

In the invention, the drying mode is not particularly limited, infrared rays, an oven and a vacuum drying oven can be adopted, the oven is adopted in the invention, and the drying temperature is more preferably 70-100 ℃, such as 100 ℃.

In the invention, the drying time is 1-6 h, such as 1 h.

According to the method disclosed by the invention, the prepared sodium acetate-based europium complex composite fluorescent material has high fluorescence intensity which can reach 2400000CPS, long fluorescence life which can reach 0.61ms, and high quantum yield which can reach 29.88%.

The inventor believes that, without being bound by any theory, the fluorescence intensity of the sodium acetate-based europium complex composite fluorescent material prepared according to the invention is remarkably increased, and the fluorescence life is remarkably prolonged, because the europium complex is subjected to steric hindrance brought by the sodium acetate powder on the surface of the sodium acetate powder, the structure of the europium complex is changed, such as bond angle, bond length and the like, and the coordination number of the complex and europium is possibly changed, so that the fluorescence intensity and the fluorescence life of the europium complex composite fluorescent material are remarkably enhanced and prolonged.

In the infrared spectrogram of the rare earth europium complex composite fluorescent material with sodium acetate as the matrix, the sodium acetate is positioned at 1400 cm and 1550 cm-^-1Can be shown in the material, indicating that sodium acetate is present in the material. The product can be observed bright red luminescence under the irradiation of an ultraviolet lamp.

According to the rare earth europium composite fluorescent materials with sodium acetate as a matrix and the preparation method thereof, the invention has the following beneficial effects:

(1) the preparation method of the composite fluorescent material is simple and easy to implement;

(2) the composite fluorescent material has high fluorescence excitation intensity, high fluorescence emission intensity and high quantum yield which can reach 29.88 percent, and the fluorescence service life is long;

(3) the composite fluorescent material prepared by the method has uniform particle size and can be controlled within a proper particle size range;

(4) the composite fluorescent material of the invention takes sodium acetate as a matrix, reduces the cost of the fluorescent composite material and is hopeful to expand the application range of the rare earth luminescent material.

Examples

Preparation of europium chloride hexahydrate

10.3675g of europium oxide white powder is weighed and added into a reaction bottle containing 20mL of deionized water, stirred and heated to 40 ℃;

slowly dropwise adding concentrated hydrochloric acid until the solid is completely dissolved (the solution becomes clear), and stopping dropwise adding the concentrated hydrochloric acid;

then vacuum-filtering to remove insoluble substances, transferring the filtrate into a 150mL small beaker, heating to 90 ℃, evaporating and crystallizing until crystal films appear on the surface of the solution, stopping heating, cooling, vacuum-filtering, collecting the filtered precipitate, transferring the filtrate, continuing the above operation until all europium chloride in the solution is separated out, transferring the filter cake into a small beaker, placing the small beaker into a dryer, drying at normal temperature for two or three days to obtain white solid powder europium chloride hexahydrate, and storing in the dryer for later use.

Example 1

Weighing dried 1.0000g of sodium acetate in a 50ml beaker, adding 30ml of absolute ethyl alcohol, putting the beaker into an ultrasonic cleaning machine, sealing the opening of the beaker with preservative paper, and carrying out ultrasonic oscillation for 30 min;

0.2781g of TPPO (1mmol), 0.3339g of TTA (1.5mmol) and 0.1294g of europium chloride hexahydrate are weighed respectively and added into a reaction bottle, then 20mL of absolute ethyl alcohol is added, stirring is carried out, and ultrasonic oscillation is carried out for 30min, so as to obtain a solution;

placing the reaction bottle in a heating sleeve, starting stirring, connecting with a reflux device, dropwise adding the pretreated sodium acetate solution into the reaction bottle, heating to reflux reaction after 10min of dropwise addition, and reacting for 2 h;

after the reaction is finished, cooling to room temperature, filtering, and drying the obtained filter cake in an oven at the temperature of 80 ℃ for 1h to obtain a product; denoted as E1.

Example 2

This example is the same as example 1 except for the amount of sodium acetate, which was 2 g; the product obtained is designated as E2.

Example 3

This example is the same as example 1 except for the amount of sodium acetate, which was 3 g; the product obtained is designated as E3.

Example 4

This example is the same as example 1 except for the amount of sodium acetate, which was 4 g; the product obtained is designated as E4.

Example 5

This example is the same as example 1 except for the amount of sodium acetate, which was 5 g; the product obtained is designated as E5.

Example 6

This example is the same as example 1 except for the amount of sodium acetate, which was 6 g; the product obtained is designated as E6.

Example 7

This example is the same as example 1 except that the amount of sodium acetate was different, i.e., 7 g; the product obtained is designated as E7.

Example 8

This example is the same as example 1 except for the amount of sodium acetate, 8 g; the product obtained is designated as E8.

Examples of the experiments

Experimental example 1 ultraviolet-visible Spectroscopy analysis of sample

Ultraviolet analysis is carried out on pure sodium acetate and the composite product prepared in the examples 1-8, a TU-1901 double-beam ultraviolet visible spectrophotometer is used for measuring a liquid-phase ultraviolet spectrum, and an ultraviolet absorption spectrum is measured in a range of 200-600nm, and the result is shown in figure 1. In FIG. 1, the blank refers to pure sodium acetate.

As can be seen from FIG. 1, the curve of the anhydrous sodium acetate sample tends to be linear on the left of the 290nm absorption peak, and qualitative analysis of the prepared complex shows that the europium complex has the highest peak near 340nm, i.e. the maximum absorption wavelength, which is behind the highest peak of the sodium acetate sample. And as the mass of the sodium acetate is increased, the maximum absorption wavelength is changed, but the wavelength is not greatly changed.

Experimental example 2 Infrared Spectroscopy of samples

The results of testing the infrared spectra of the pure sodium acetate and the composite products prepared in examples 1 to 8 are shown in FIG. 2. Mixing the rare earth europium complex composite fluorescent material prepared for infrared spectrum and potassium bromide in a ratio of 1:100, grinding, drying, tabletting on a tabletting machine, and performing Fourier transform infrared spectrum (Nicolet iS50) at 4000cm^-1-400cm^-1The range was measured. In FIG. 2, the blank refers to pure sodium acetate.

As can be seen from FIG. 2, COO^-Has a division of symmetric and asymmetric stretching vibration, wherein the symmetric stretching vibration is at 1400nm^-1Near, asymmetric stretching vibration at 1550-^-1Here, the absorption was all stronger. In comparison of the characteristic peaks of the complexes, at 1000nm^-1The distinct peaks appearing nearby may be characteristic peaks of hydroxyl functionality in hydration, at 1500cm^-1-1650cm^-1The strong broad peak belongs to the characteristic absorption peak of anhydrous sodium acetate, and the peak is red-shifted with the mass of the sodium acetate, which indicates that the europium complex has formed a complex with the anhydrous sodium acetate. It can be concluded that as the reaction proceeds, less ligand is present alone, indicating that the ligand is involved in the reaction and the reaction is more complete.

XRD analysis of sample of Experimental example 3

XRD analysis was performed on pure sodium acetate and the product samples of examples 1 to 8, and the results are shown in FIG. 3. In FIG. 3, the blank refers to pure sodium acetate.

As can be seen from FIG. 3, the four peaks of the complex become more and more obvious with the increase of the mass thereof, and the comparison with the peaks of pure sodium acetate proves that the prepared complex contains sodium acetate, and the position of the peak of the obtained product is slightly shifted compared with the peak of sodium acetate by 9 degrees, the position of the overall trend peak is shifted to the right, and the average shift is 0.14 degrees. The peak position movement is reduced along with the increase of the amount of the sodium acetate, namely, the mass of the sodium acetate in the compound is more close to that of a pure sodium acetate sample, which indicates that the europium complex in the product is basically attached to the surface of the sodium acetate particle, and the europium complex occupies part of the space of the sodium acetate particle, but the main crystal form of the sodium acetate is not changed, which indicates that the sodium acetate does not participate in the reaction, so that the sodium acetate is supposed to exist mainly as a 'carrier' of the composite material, but the increase of the inner core can bias the kurtosis of the compound to the pure sample, and.

Thermo gravimetric differential thermal analysis of the samples of Experimental example 4

Thermogravimetric-differential thermal analysis was performed on the samples of example 1, example 3, and example 8, and the results are shown in fig. 4. FIG. 4 is a thermogravimetric analysis of composite materials prepared by europium complexes adsorbed on sodium acetate of different masses at room temperature ranging from 0 ℃ to 800 ℃. In fig. 4, the weight of the samples with respect to temperature is plotted in the upper part for samples with numbers E1, E3 and E8, and the heat flow with respect to temperature is plotted in the lower part.

The thermal analysis conditions are nitrogen atmosphere, the heating rate is 10 ℃/min, the upper part is the weight change with temperature, the lower part is the heat flow change with temperature, the analysis of the upper part is that the composite weight is obviously decomposed in two stages at 50-100 ℃ with the temperature rising, the analysis of thermogravimetry is that the stage is likely to be water vapor in the air, the second stage is likely to be crystal water of europium complex, the weight of the composite slightly slides down at 200-350 ℃, the thermal decomposition of ligand organic matters generated by the combination of europium chloride and TTA and TPPO is likely to occur, the data is consulted to know that the boiling point of sodium acetate is 400 ℃, and the curve of the composite is steeply reduced at 400-500 ℃, so that the sodium acetate is presumed to be decomposed at the moment, and the larger the mass of the sodium acetate is, the curve of E8 is different from those of E1 and E3, probably because more is more, the moisture in the air is absorbed, so that the crystal water is generated and the weight loss is more.

Experiment ofExample 5 laser particle size analysis of samples

The samples of examples 1 to 8 and sodium acetate-free samples were subjected to particle size analysis using a laser particle sizer, and the analysis results of examples 1 to 8 are shown in table 1 and the line graphs of the average particle diameters shown in fig. 5.

TABLE 1 particle size range table for the products of examples 1-8

Numbering	Particle size distribution Range (nm)	Average particle diameter (nm)
			E1	31.0-10000.0	89.2
E2	192.7-10000.0	404.5
			E3	216.4-2218.5	375.1
E4	64.4-10000.0	104.7
			E5	186.1-4832.4	371.6
E6	158.5-2801.3	286.6
			E7	198.6-3915.5	346.6
E8	216.1-2701.5	398.2

As can be seen from table 1 and fig. 5, the particle size range of the pure particles of anhydrous sodium acetate is relatively uniform for the composites. And with the increase of the amount of the sodium acetate, the range of the particle size of the compound is wider, and the particle size becomes smaller. The reason may be that after the complex is formed, the inner core and the ligand play a role of a bridge, so that complex particles are agglomerated, large particles wrap small particles, and the particle size is reduced.

Experimental example 6 fluorescence emission spectrum of sample

FIG. 6 shows fluorescence emission spectra, λ, of the products (complex fluorescent materials) of examples 1 to 8_ex358nm for emission detection wavelength;

FIG. 7 shows fluorescence emission line graphs of the products (composite fluorescent materials) of examples 1 to 8; lambda [ alpha ]_ex358nm for emission detection wavelength;

as can be seen from FIG. 6, the fluorescence intensity of the composite fluorescent material reaches a maximum around 614 nm.

As can be seen from fig. 7, the emission intensity gradually decreased with the increase in the mass of sodium acetate, and the emission intensity was the greatest at 1g of sodium acetate, and then increased occasionally, but decreased overall. It shows that when the relative amount of the complex europium chloride is reduced, the fluorescence intensity of the complex is in negative correlation with the addition amount of sodium acetate.

Fluorescence excitation spectrum of sample of Experimental example 7

The fluorescence spectrum was performed using an FM4NIR TCSPC fluorescence spectrometer using a 10 x dimmer to reduce the light source intensity. The excitation spectrum of the complex is measured by lambda_emAnd 614nm is the excitation detection wavelength.

FIG. 8 shows fluorescence excitation spectra of products of examples 1 to 8;

FIG. 9 shows a line graph of fluorescence excitation spectra of the products of examples 1-8;

as can be seen from FIG. 8, the intensity of the excitation light of the composite fluorescent material reaches a maximum around 369 nm. It can be seen from fig. 9 that the excitation intensity of the composite fluorescent material decreases and increases as the mass of sodium acetate increases, but the excitation intensity generally decreases, and it is known that the amount of sodium acetate affects the luminescence property of the composite, and the luminescence property decreases as the relative ratio of the amount of sodium acetate to the amount of europium complex increases.

Experimental example 8 analysis of fluorescence lifetime of sample

The fluorescence lifetime test uses an LED excitation light source to collect 50000 photons, and the fluorescence lifetime analysis adopts a secondary fitting method. The results are shown in table 2 and fig. 10.

Table 2 shows the mean fluorescence lifetimes of the composite phosphors of examples 1-8 and a fitted CHISQ table;

TABLE 2 mean fluorescence lifetimes of the products of examples 1-8

Numbering	Mean fluorescence lifetime	CHISQ
			E1	0.5784109ms	1.033399
E2	0.6148875ms	1.0905
			E3	0.5978948ms	1.01687
E4	0.6168977ms	1.076154
			E5	0.6052902ms	1.028569
E6	0.6052902ms	1.028569
			E7	0.5889978ms	1.065173
E8	0.6122079ms	1.121326

We know that the closer the CHISQ to fit is to 1, the better. As can be seen from Table 2, the CHISQ values corresponding to the mass of anhydrous sodium acetate increased to approximately 1, indicating a better fit. It is known from the literature that the fluorescence lifetime of a substance is determined mainly by the spontaneous emission transition lifetime and the nonradiative transition lifetime according to the excited state lifetime theory. Spontaneous emission lifetime is independent of temperature, but sensitive to environmental perturbations. In Table 2, the average fluorescence lifetime of the complexes incorporating different amounts of sodium acetate did not fluctuate much.

As can be seen from FIG. 10, the average lifetime of 1-2 g fluorescence suddenly increases, and after 2g fluorescence fluctuates greatly with the increase of the mass of anhydrous sodium acetate, but the whole system gradually increases and occasionally decreases, so the fluorescence lifetime is not increased or decreased by when the amount of the fluorescent powder is increased³⁺5D of₀→7F₂The characteristic energy level of the Eu increases along with the increase of the content of the sodium acetate, and the Eu increases during the increase of the sodium acetate³⁺Part of the energy is obtained from the sodium acetate, so that the characteristic energy level life of the sodium acetate is prolonged.

Experimental example 9 fluorescence quantum yield analysis of sample

The fluorescence quantum yield (Yf) is the ratio of the number of photons of the emitted fluorescence to the number of photons of the absorbed excitation light after absorption by the fluorescent substance. The larger the value of YF, the more fluorescent the compound, while the fluorescence quantum yield of non-fluorescent material is equal to or very close to zero.

And under the same excitation condition, respectively measuring the integrated fluorescence intensity of two samples of the fluorescence pattern to be measured and the reference fluorescence standard substance with known quantum yield and the absorbance of incident light with the same excitation wavelength of .

The quantum yields of the products of examples 1-8 are shown in table 3 and fig. 11, which are plots of quantum yields.

TABLE 3 Quantum yield table for product samples of examples 1-8

Numbering	Maximum absorption waveLong (nm)	Absorbance (ABS)	Fluorescence quantum yield
				E1	619	0.031	29.88
E2	618	0.033	29.94
				E3	614	0.036	27.60
E4	614	0.034	29.44
				E5	619	0.036	27.81
E6	617	0.031	27.56
				E7	616	0.056	26.26
E8	619	0.048	27.36

As can be seen in Table 3, the mass of sodium acetate has little effect on the maximum absorption wavelength of the complex, but can affect its absorbance, and the mass of sodium acetate is inversely related to the absorbance.

As can be seen from fig. 11, when the amount of the core is 1-2 g, the quantum yield of the composite is close to 30, which indicates that the fluorescence effect is better, and the quantum yield is decreased with the increase of the core mass, so that it is known that the core mass is inversely proportional to the quantum yield and the fluorescence effect.

According to the invention, the rare earth europium composite fluorescent material taking sodium acetate as a matrix is prepared, and the product has excellent performance, higher fluorescence quantum efficiency and good fluorescence performance through characterization. The rare earth composite material is synthesized by using cheap sodium acetate, TTA and TPPO, so that the cost of the luminescent material is reduced, the prepared material has long service life, high quantum yield and good fluorescence performance, and the research range of the rare earth europium complex is widened.

The invention has been described in detail with reference to specific embodiments and illustrative examples, but the description is not intended to be construed in a limiting sense. Those skilled in the art will appreciate that various equivalent substitutions, modifications or improvements may be made to the technical solution of the present invention and its embodiments without departing from the spirit and scope of the present invention, which fall within the scope of the present invention. The scope of the invention is defined by the appended claims.

Claims

1, rare earth fluorescent materials, which are characterized in that the fluorescent materials are composite fluorescent materials, and the maximum absorption wavelength of the ultraviolet visible spectrum of the composite fluorescent materials is near 340 nm.

2. The rare earth fluorescent material as claimed in claim 1, wherein the fluorescence intensity is 2400000CPS and the quantum yield is 29.88%.

3. The rare earth fluorescent material according to claim 1 or 2,

4. The rare earth fluorescent material according to claim 1 or 2,

Method for the preparation of rare earth phosphors, preferably for the preparation of the rare earth phosphor according to any of claims 1 to 4 to , characterized in that the method comprises the following steps:

step 1: pretreating a substrate material;

step 2: mixing a ligand and a rare earth compound to obtain a solution;

and 4, step 4: and carrying out post-treatment to obtain a final product.

6. The production method according to claim 5,

in the step 1, the matrix substance is oxygen-containing inorganic salt;

the pretreatment comprises mixing the matrix substance with a dispersing agent which is or more of methanol, ethanol and isopropanol and optionally carrying out ultrasonic vibration.

7. The production method according to claim 5,

in the step 2, the ligand is a dual ligand, the dual ligand is 2-thenoyltrifluoroacetone and triphenyl phosphorus oxide, and the molar ratio of the dual ligand is (0.5-4.5): 1;

the rare earth compound is europium trichloride;

preferably, the solvent is or more selected from methanol, ethanol and isopropanol, and more preferably the same dispersant used in step 1.

8. The method of claim 7, wherein the europium trichloride is prepared by a process comprising:

step 2-2, adding acid into the step 2-1 and reacting;

step 2-3, post-treating to obtain a product;

preferably, the first and second electrodes are formed of a metal,

in step 2-1, the solvent is methanol, ethanol, isopropanol or water, and more preferably water; setting the temperature to be 35-65 ℃;

in step 2-3, the post-treatment comprises filtration, the filtrate is evaporated for crystallization, and then the crystal product is filtered and collected.

9. The production method according to claim 5,

in the step 3, the set conditions comprise that the reaction temperature is 50-95 ℃ and the reaction time is 1-5 h.

10. The production method according to claim 5,

in the step 4, the post-treatment comprises cooling to room temperature after the reaction is finished, filtering and drying, wherein preferably, the drying temperature is 60-110 ℃.