CN103087705A - A high-strength rare earth-doped up-conversion luminescent nanomaterial and its preparation method - Google Patents

Abstract

The present invention provides a method for improving the luminous efficiency of rare earth doped up-conversion nano luminescent materials by changing the use of ligands. The method adopts a hydrothermal-solvothermal method for synthesis, the organic ligand is an organic compound such as monocarboxylic acid, dicarboxylic acid or polycarboxylic acid, amine, etc., the molar ratio of rare earth ion to ligand is 2:1-1:100, the molar ratio of NaOH to ligand is 0:1-1:1, water/ethanol, water/n-propanol, water/isopropanol, water/n-butanol, water/acetone or water/ethylene glycol system is used as solvent, the temperature range is 180-240 degrees, the reaction time is 2-24 hours, and the F-/Re value is 4-12. The present invention mainly solves the problems of selecting multiple types of ligands for synthesizing up-conversion nano luminescent materials, improving the luminous efficiency of rare earth doped up-conversion and synthesizing water-soluble up-conversion nano luminescent materials.

Description

A high-strength rare earth-doped up-conversion luminescent nanomaterial and its preparation method

technical field

The invention relates to a high-intensity rare earth doped up-conversion luminescent nano material and a preparation method thereof, belonging to the field of nano material preparation.

Background technique

Rare earth-doped upconversion luminescent nanomaterials have unique luminescent properties, such as: rich optical properties, narrow emission peaks, high luminous color purity, long fluorescence lifetime, near-infrared excitation, etc., making them ideal for laser displays, optical data storage, etc. , biomarkers, solar cells, etc. have significant potential applications. The preparation methods of up-conversion luminescent materials are mainly divided into two types: high-temperature oil-phase method and hydrothermal-solvothermal method. There are fewer ligands to choose; while the hydrothermal-solvothermal method uses high temperature and high pressure methods to obtain high-quality nanoparticles. This synthesis method makes the reaction temperature relatively mild due to high pressure conditions, and the range of ligand selection is largely By extension, some short carbon chain compounds with lower boiling points can also be used to synthesize up-conversion nano-luminescent materials.

The luminous efficiency of up-conversion luminescent materials has always been the main factor hindering their industrial application, and how to improve the luminous efficiency of up-conversion luminescent nanomaterials has been receiving great attention. Core-shell structure nanomaterials, plasmon resonance method, metal doping and other methods can improve the luminous efficiency of upconversion nanomaterials to a certain extent, but these have the disadvantages of preparation replication and high price.

With the application and development of upconversion luminescent nanomaterials in the fields of biology and medicine, water-soluble upconversion nanoluminescent materials are urgently needed to be utilized. Although water-soluble upconversion luminescent nanomaterials can be obtained by ligand replacement or polymer coating, these methods are not only complicated to operate, but also have low efficiency and high cost.

Contents of the invention

The purpose of the present invention is to solve the preparation of up-conversion nano-luminescent materials with less ligand selectivity and to synthesize high-luminous-intensity, color and water-soluble up-conversion nano-luminescent materials by selecting different ligands.

The technical solution of the present invention is to change the carbon chain length of the ligand, the type and quantity of the coordination functional group, and improve the luminous efficiency of the up-conversion luminescent nanomaterial by reducing the non-radiative transition of the activated ion caused by the stretching vibration of the ligand.

A high-strength rare-earth-doped up-conversion luminescent nanomaterial, the material is a nano-material formed by combining a ligand L with rare earth ions of a rare-earth-doped up-conversion luminescent nanomaterial through a coordination chemical bond, and the rare-earth doped up-conversion luminescence Nanomaterials have the following structure:

MNF _y :Yb ³⁺ ,Re

Wherein, M is selected from one of Na ⁺ , Li ⁺ , K ⁺ , Mg ²⁺ , Ca ²⁺ and Ba ²⁺ ; N is Y ³⁺ , Gd ³⁺ or Lu ³⁺ ; y is 4 or 5; Re is Er ³⁺ , Ho ³⁺ or Tm ³⁺ ;

The ligand L is an organic compound with a C1-C18 carbon chain as a skeleton, and the organic compound contains 1-6 substituents, and the substituents are selected from at least one of carboxyl, hydroxyl and amino.

The MNF _y :Yb ³⁺ , Re compound in the present invention refers to a compound in which Yb ³⁺ and Re ions are doped at the N position of the MNF _y- type compound. When the M-position ion is a monovalent ion, y is 4, and when a divalent ion, y is 5. The selection of M, N, Re ions in this type of compound, and the determination of the doping amount of Yb ³⁺ and Re ions are prior art in the art, and those skilled in the art can determine the luminous intensity according to the requirements of the luminescent material. .

In the present invention, the preferred MNF _y :Yb ³⁺ , Re compounds are NaYF ₄ :Yb,Er, NaYF ₄ :Yb,Tm, NaYF ₄ :Yb,Ho, LiYF ₄ :Yb,Er, KYF ₄ :Yb,Er, MgYF ₅ : Yb, Er, CaYF ₅ : Yb, Er, BaYF ₅ : Yb, Er, NaGdF ₄ : Yb, Er, or NaLuF ₄ : Yb, Er, more preferably NaYF ₄ : Yb, Er, NaYF ₄ : Yb , Tm or NaGdF ₄ :Yb, Er.

In the present invention, the preferred MNF _y : Yb ³⁺ , the molar ratio of Yb ³⁺ and Re in the Re compound is 10:1, more preferably the molar doping amounts of Yb ³⁺ and Re ions are 20% and 2%.

The C1-C18 carbon chains in the present invention include saturated alkyl groups, unsaturated alkyl groups (alkene groups), aryl groups and the like. The term "alkyl" as used herein includes straight chain alkyl groups and branched chain alkyl groups. If a single alkyl group such as "propyl" is mentioned, it only refers to a straight chain alkyl group, and if a single branched chain alkyl group such as "isopropyl" is mentioned, it only refers to a branched chain alkyl group.

The high-strength rare earth doped up-conversion luminescent nanomaterials of the present invention preferably said ligand L is an organic compound with general formula I:

In the formula, R ₁ is C ₁ -C ₁₇ saturated or unsaturated alkyl; C ₁ -C ₁₇ saturated alkyl substituted by hydroxyl or amino; C ₁ -C ₁₇ unsaturated alkyl or aryl substituted by hydroxyl or amino.

More preferably propionic acid, 4-pentenoic acid, maleic acid, α-hydroxybutyric acid, alanine, oleic acid, benzoic acid or salicylic acid, still more preferably propionic acid, 4-pentenoic acid, Alpha-Hydroxybutyrate, Alanine, Benzoic Acid, or Salicylic Acid.

Propionic Acid 4-Pentenoic Acid α-Hydroxybutyric Acid

Alanine Benzoic Acid Salicylic Acid

The high-intensity rare earth doped up-conversion luminescent nanomaterials of the present invention preferably said ligand L is an organic compound having the general formula II:

In the formula: R ₂ is C ₁ ~ C ₁₆ saturated or unsaturated alkyl; C ₁ ~ C ₁₆ saturated or unsaturated alkyl substituted by hydroxyl, amino or carboxyl; C ₁ ~ C ₁₆ unsaturated alkyl substituted by carboxy base, phenyl, aryl.

More preferably, it is succinic acid, malic acid, tartaric acid, phthalic acid, citric acid or ethylenediaminetetraacetic acid.

Succinic Acid Malic Acid Tartaric Acid

Phthalic acid ethylenediaminetetraacetic acid

In the high-intensity rare earth-doped upconversion luminescent nanomaterial of the present invention, the organic ligand L is preferably butylamine, ethylenediamine, or triethylenetetramine.

Butylamine Ethylenediamine

            Triethylenetetramine

Principle of the present invention:

Rare earth-doped upconversion nano-luminescent materials are synthesized by hydrothermal-solvothermal method, because the high-pressure airtight environment makes the reaction temperature relatively low, and the boiling point of the reaction material increases, so that the available ligands are limited by external conditions. That is, the number of ligands to choose from increases. Figure 5 shows the luminescence principle of rare earth doped up-conversion luminescent materials. The activator Er3+ has multiple energy levels, and different energy levels correspond to light of different wavelengths. External energy vibrations will cause Er3 ⁺ to transition at different energy levels. Organic ligands and up-conversion nano-luminescent materials are combined through coordination and complex bonds. Ligands containing different carbon chain lengths and groups have their own stretching vibration energy, such as: 2800-3000cm ^-1 stretching of CH Vibration energy, 3300-3400cm ^-1 stretching vibration energy of OH, 3300-3500cm ^-1 stretching vibration energy of NH, ⁴ S _3/2 - ⁴ F _9/2 and ⁴ F _9/2 - ⁴ with Er ³⁺ The energy difference between the I _11/2 energy levels is matched, which affects the non-radiative transition of the activator Er3+ in the up-conversion nano-luminescent material, resulting in the change of the luminous intensity and luminous color of the up-conversion nano-luminescent material. Due to the increase in the number of CH bonds in the ligands with long carbon chains, the stretching vibration energy of the ligands at 2800-3000cm ^-1 is enhanced, which increases the energy level of Er ³⁺ in ⁴ S _3/2 - ⁴ F _9/2 The non-radiative transition between them further reduces the luminous efficiency of upconversion nanoluminescent materials. The addition of -OH, -NH ₂ or -COOH groups enhances the stretching vibration energy of the ligand at 3300-3500cm ^-1 and increases the non-separation between ⁴ F _9/2 - ⁴ I _11/2 energy levels. The radiative transition reduces the luminous efficiency of upconversion nanoluminescent materials. Ligands with different carbon chain lengths or ligands containing different numbers of -OH, -NH ₂ , -COOH groups have different water solubility, while organic ligands are complexed on the surface of upconversion nanoluminescent materials in the form of coordination bonds , so that the combination products of the ligand and the up-conversion nano-luminescent material have different degrees of water solubility.

Another object of the present invention is to provide a preparation method of the above-mentioned high-intensity rare earth-doped up-conversion luminescent nanomaterial.

A preparation method of a high-intensity rare earth-doped upconversion luminescent nanomaterial, the method is a hydrothermal-organic solvothermal synthesis method, and a rare earth ion source compound and a ligand L compound are prepared according to the target MNF _y : Yb ³⁺ , Re compound Soluble in the reaction solvent, wherein the molar ratio of the rare earth element ion to the ligand compound is 2:1~1:100, add NaOH, the molar ratio of NaOH to the ligand L compound is 0:1~1:1, and prepare solution A ; Dissolve the alkali metal fluoride in the reaction solvent to form solution B; add solution B to solution A, the molar ratio of fluoride ions to rare earth ions is 4-12, mix well and move to the reaction kettle at 180-240°C , reaction 2～24h;

Wherein, the reaction solvent is water-ethanol, water-methanol, water-isopropanol, water-n-propanol, water-n-butanol or water-ethylene glycol solvent, wherein the volume ratio of water to organic solvent is 2:1 ~1:5, more preferably water-ethanol, the reaction solvent formed by the volume ratio of water and ethanol is 1:1.

Wherein, M is selected from one of Na ⁺ , Li ⁺ , K ⁺ , Mg ²⁺ , Ca ²⁺ and Ba ²⁺ ; N is Y ³⁺ , Gd ³⁺ or Lu ³⁺ ; y is 4 or 5; Re is Er ³⁺ , Ho ³⁺ or Tm ³⁺ ;

The ligand L is an organic compound with a C1-C18 carbon chain as a skeleton, and the organic compound contains 1-6 substituents, and the substituents are selected from at least one of carboxyl, hydroxyl and amino.

The rare earth ion source compound in the above method is preferably a rare earth ion nitrate, and the rare earth ion is Y ³⁺ , Gd ³⁺ , Lu ³⁺ , Er ³⁺ , Ho ³⁺ or Tm ³⁺ ; the alkali metal fluoride is NaF, KF.

The preparation method of the high-strength rare earth-doped up-conversion luminescent nanomaterial in the present invention preferably has a rare earth nitrate: deionized water: ethanol ratio of 1:20:20 (mmol:mL:mL) in solution A; The metal fluoride: deionized water: ethanol ratio is 4-12:10:10 (mmol:mL:mL).

The above method further includes the step of aftertreatment: after cooling the reactor, remove the supernatant, collect the solid, wash twice with the mixed liquid of ethanol and water, centrifuge and dry.

A preferred technical solution of the preparation method of the high-strength rare earth-doped up-conversion luminescent nanomaterial in the present invention is as follows:

Take 0.4M rare earth ion nitrate aqueous solution in a beaker, the volume ratio of rare earth ion nitrate aqueous solution: deionized water: organic solvent is 2.5:2.5～30:11～40, add deionized water and organic solvent ethanol, and then add Ligand compound and NaOH, wherein, the molar ratio of rare earth element ion and ligand compound is 2:1～1:100, the molar ratio of NaOH and ligand compound is 0:1～1:1, stir, form solution A;

According to the ratio of alkali metal fluoride: deionized water: organic solvent is 168~504:10:10 (mg:mL:mL), dissolve NaF in the mixture of deionized water and ethanol, and stir to form solution B;

Under stirring, add solution B dropwise to A, the molar ratio of fluoride ions to rare earth ions is 4-12, after the dropwise addition, ultrasonically disperse, transfer to a hydrothermal kettle for heating, the heating temperature is 180-240°C, Reaction 2 ~ 24h.

After the reactor was cooled, the supernatant was removed, and the solid was collected, washed twice with a mixed liquid of ethanol and water, centrifuged, and dried.

In the preparation method of the high-intensity rare earth doped up-conversion luminescent nanomaterial of the present invention, the ligand L is preferably an organic compound having the general formula I:

In the formula, R ₁ is C ₁ -C ₁₇ saturated or unsaturated alkyl; C ₁ -C ₁₇ saturated alkyl substituted by hydroxyl or amino; C ₁ -C ₁₇ unsaturated alkyl or aryl substituted by hydroxyl or amino.

More preferably propionic acid, 4-pentenoic acid, maleic acid, α-hydroxybutyric acid, alanine, oleic acid, benzoic acid or salicylic acid, still more preferably propionic acid, 4-pentenoic acid, Alpha-Hydroxybutyrate, Alanine, Benzoic Acid, or Salicylic Acid.

Propionic Acid 4-Pentenoic Acid α-Hydroxybutyric Acid

Alanine Benzoic Acid Salicylic Acid

In the preparation method of the high-intensity rare earth-doped upconversion luminescent nanomaterial of the present invention, the ligand L is preferably an organic compound having the general formula II:

In the formula: R ₂ is C ₁ ~ C ₁₆ saturated or unsaturated alkyl; C ₁ ~ C ₁₆ saturated or unsaturated alkyl substituted by hydroxyl, amino or carboxyl; C ₁ ~ C ₁₆ unsaturated alkyl substituted by carboxy base, phenyl, aryl.

More preferably, it is succinic acid, malic acid, tartaric acid, phthalic acid, citric acid or ethylenediaminetetraacetic acid.

Succinic Acid Tartaric Acid Malic Acid

Phthalic acid ethylenediaminetetraacetic acid

In the preparation method of the high-intensity rare earth-doped upconversion luminescent nanomaterial of the present invention, the organic ligand L is preferably butylamine, ethylenediamine, or triethylenetetramine.

Butylamine Ethylenediamine

         Triethylenetetramine

The beneficial effects of the invention are: the invention solves the disadvantages of low ligand selectivity and low luminous efficiency of rare earth-doped up-conversion nano-luminescent materials, and can directly synthesize up-conversion nano-luminescent materials with different water solubility. In the synthesis of rare earth-doped up-conversion nano-luminescent materials, the number of ligands reported is very limited, such as: oleic acid, sodium citrate, disodium edetate, oleylamine, trioctylphosphine, etc., and the present invention A variety of ligands are available for selection. In the methods of improving the luminous efficiency of upconversion nanoluminescent materials, methods such as core-shell structure, plasmon resonance, and metal ion doping are generally used, but these methods are not only complicated and expensive to prepare, but can be directly synthesized by selecting different ligands. High-efficiency upconversion nanoluminescent materials. In addition, by selecting different types of ligands, such as with different numbers or types of hydrophilic groups, the up-conversion nano-luminescent materials complexed with the ligands through coordination bonds have different degrees of water solubility.

Description of drawings

Fig. 1 is the XRD pattern of NaYF ₄ :Yb, Er nanocrystals synthesized with propionic acid, butyric acid, hexanoic acid, capric acid, myristic acid and oleic acid as ligands in Examples 2-7. Figure 1 shows that the XRD spectra of substances synthesized with carboxylic acids of different carbon chain lengths as ligands are consistent with the standard hexagonal crystal phase NaYF ₄ :Yb,Er cards, that is, the synthesized substances are all hexagonal phase NaYF ₄ :Yb, Er crystals. The change of the carbon chain length of the ligand will not affect the structure and crystal phase of the product.

Fig. 2 is an upconversion fluorescence spectrum diagram of NaYF ₄ :Yb, Er nanocrystals synthesized with propionic acid, butyric acid, hexanoic acid, capric acid, myristic acid and oleic acid as ligands in Examples 2-7. Figure 2 shows that with the increase of the carbon chain length of the ligand, the luminescence intensity of NaYF ₄ : Yb, Er nanocrystals gradually weakens, while the luminescence intensity of NaYF ₄ : Yb, Er nanocrystals synthesized with propionic acid as a ligand is weaker than that of butyric acid The synthesized NaYF ₄ :Yb,Er nanocrystals are mainly due to the reduction of ligand particle size. The longer the carbon chain of the ligand, the weaker the luminescence intensity of the synthesized NaYF ₄ :Yb, Er nanocrystals.

Fig. 3 is an up-conversion fluorescence spectrum diagram of NaYF ₄ :Yb, Er nanocrystals synthesized with hexanoic acid, adipic acid, citric acid and ethylenediaminetetraacetic acid as ligands in Examples 13-16. Caproic acid, adipic acid, citric acid and EDTA have similar carbon chain lengths, but the number of carboxylic acids is 1, 2, 3 and 4, respectively. Figure 3 shows that with the increase of the number of carboxylic acids in the ligand, the luminescence intensity of the synthesized NaYF ₄ :Yb,Er nanocrystals gradually weakens.

Fig. 4 is an upconversion fluorescence spectrum of NaYF ₄ :Yb, Er nanocrystals synthesized with butylamine, diethylenetriamine and triethylenetetramine as ligands in Examples 17-19. Figure 4 shows that as the number of amino groups in the ligand increases, the luminescence intensity of the synthesized NaYF ₄ :Yb,Er nanocrystals gradually decreases.

Fig. 5 shows the luminescent principle of the rare earth-doped up-conversion luminescent material.

Detailed ways

The following non-limiting examples can enable those skilled in the art to understand the present invention more fully, but do not limit the present invention in any way.

Example 1

Take 2.5mL of 0.4M 78%Y(NO ₃ ) ₃ , 20%Yb(NO ₃ ) ₃ , 2%Er(NO ₃ ) ₃ aqueous solution in a beaker, add 16mL of deionized water and 18.5mL of ethanol, and then Add 7ml of oleic acid and stir to form solution A. Weigh 504 mg of NaF and dissolve it in 10 mL of water and 10 mL of ethanol, and stir to form solution B. After stirring A for 30 minutes, add solution B dropwise to A under stirring. After the dropwise addition, sonicate for half an hour, transfer to a 75mL hydrothermal kettle, screw the lid on, and heat in an oven at a heating temperature of 200 degrees. React for 10 hours, cool down, pour off the supernatant, collect the solid below, wash twice with a mixture of ethanol and water, centrifuge, and dry to obtain NaYF ₄ :Yb,Er complexed with oleic acid ligand.

Embodiment 2-7

Take 2.5mL of 0.4M 78%Y(NO ₃ ) ₃ , 20%Yb(NO ₃ ) ₃ , 2%Er(NO ₃ ) ₃ aqueous solution in a beaker, add 14mL of deionized water and 16.5mL of ethanol, add 7ml of propionic acid, butyric acid, hexanoic acid, capric acid, myristic acid or oleic acid and 0.7g of NaOH were stirred to form solution A. Weigh 504 mg of NaF and dissolve it in 10 mL of water and 10 mL of ethanol, and stir to form solution B. After stirring A for 30 minutes, add solution B dropwise to A under stirring. After the dropwise addition, sonicate for half an hour, transfer to a 75mL hydrothermal kettle, screw the lid on, and heat in an oven at a heating temperature of 200 degrees. React for 7 hours, cool down, pour off the supernatant, collect the solid below, wash twice with a mixed liquid of ethanol and water, centrifuge, and dry to obtain NaYF ₄ : Yb, Er nanoparticles complexed with carboxylic acid ligands of different carbon chain lengths crystals.

Embodiment 8～9

Take 2.5mL of 0.4M 78%Y(NO ₃ ) ₃ , 20%Yb(NO ₃ ) ₃ , 2%Er(NO ₃ ) ₃ aqueous solution in a beaker, add 17.5mL of deionized water and 20mL of ethanol, add 1 mmol of benzoic acid or salicylic acid to form solution A. Weigh 504 mg of NaF and dissolve it in 10 mL of water and 10 mL of ethanol, and stir to form solution B. After stirring A for 30 minutes, add solution B dropwise to A under stirring. After the dropwise addition, sonicate for half an hour, transfer to a 75mL hydrothermal kettle, screw the lid on, and heat in an oven at a heating temperature of 200 degrees. React for 7 hours, cool down, pour off the supernatant, collect the solid below, wash twice with a mixture of ethanol and water, centrifuge, and dry to obtain NaYF ₄ :Yb,Er nanocrystals complexed with benzoic acid or salicylic acid.

Examples 10-12

Take 2.5mL of 0.4M 78%Y(NO ₃ ) ₃ , 20%Yb(NO ₃ ) ₃ , 2%Er(NO ₃ ) ₃ aqueous solution in a beaker, add 17.5mL of deionized water and 20mL of ethanol, add 1 mmol of succinic acid, malic acid or tartaric acid to form solution A. Weigh 504 mg of NaF and dissolve it in 10 mL of water and 10 mL of ethanol, and stir to form solution B. After stirring A for 30 minutes, add solution B dropwise to A under stirring. After the dropwise addition, sonicate for half an hour, transfer to a 75mL hydrothermal kettle, screw the lid on, and heat in an oven at a heating temperature of 200 degrees. React for 7 hours, cool down, pour off the supernatant, collect the solid below, wash twice with a mixed liquid of ethanol and water, centrifuge, and dry to obtain NaYF ₄ :Yb,Er nanoparticles complexed with succinic acid, malic acid or tartaric acid crystals.

Examples 13-16

Take 2.5mL of 0.4M 78%Y(NO ₃ ) ₃ , 20%Yb(NO ₃ ) ₃ , 2%Er(NO ₃ ) ₃ aqueous solution in a beaker, add 17.5mL of deionized water and 20mL of ethanol, add 1 mmol of caproic acid, adipic acid, sodium citrate or disodium edetate to form solution A. Weigh 504 mg of NaF and dissolve it in 10 mL of water and 10 mL of ethanol, and stir to form solution B. After stirring A for 30 minutes, add solution B dropwise to A under stirring. After the dropwise addition, sonicate for half an hour, transfer to a 75mL hydrothermal kettle, screw the lid on, and heat in an oven at a heating temperature of 200 degrees. React for 7 hours, cool down, pour off the supernatant, collect the solid below, wash twice with a mixed liquid of ethanol and water, centrifuge, and dry to obtain NaYF ₄ : Yb, Er nanocrystals complexed with different carboxylic acid ligands .

Examples 17-19

Take 2.5mL of 0.4M 78%Y(NO ₃ ) ₃ , 20%Yb(NO ₃ ) ₃ , 2%Er(NO ₃ ) ₃ aqueous solution in a beaker, add 17.5mL of deionized water and 20mL of ethanol, add 0.2 mL of butylamine, diethylenetriamine or triethylenetetramine to form solution A. Weigh 504 mg of NaF and dissolve it in 10 mL of water and 10 mL of ethanol, and stir to form solution B. After stirring A for 30 minutes, add solution B dropwise to A under stirring. After the dropwise addition, sonicate for half an hour, transfer to a 75mL hydrothermal kettle, screw the lid on, and heat in an oven at a heating temperature of 200 degrees. React for 7 hours, cool down, pour off the supernatant, collect the solid below, wash twice with a mixture of ethanol and water, centrifuge, and dry to obtain NaYF ₄ :Yb, Er nanocrystals complexed with different amines.

Example 20

Take 2.5mL of 0.4M 78%Y(NO ₃ ) ₃ , 20%Yb(NO ₃ ) ₃ , 2%Tm(NO ₃ ) ₃ aqueous solution in a beaker, add 14mL of deionized water and 16.5mL of ethanol, and then Add 7ml of oleic acid and 0.7g of NaOH, stir to form solution A. Weigh 504 mg of NaF and dissolve it in 10 mL of water and 10 mL of ethanol, and stir to form solution B. After stirring A for 30 minutes, add solution B dropwise to A under stirring. After the dropwise addition, sonicate for half an hour, transfer to a 75mL hydrothermal kettle, screw the lid on, and heat in an oven at a heating temperature of 200 degrees. React for 7 hours, cool down, pour off the supernatant, collect the solid below, wash twice with a mixture of ethanol and water, centrifuge, and dry to obtain NaYF ₄ :Yb,Tm complexed with oleic acid ligand.

Example 21

Take 2.5mL of 0.4M 78%Gd(NO ₃ ) ₃ , 20%Yb(NO ₃ ) ₃ , 2%Tm(NO ₃ ) ₃ aqueous solution in a beaker, add 14mL of deionized water and 16.5mL of ethanol, and then Add 7ml of oleic acid and 0.7g of NaOH, stir to form solution A. Weigh 504 mg of NaF and dissolve it in 10 mL of water and 10 mL of ethanol, and stir to form solution B. After stirring A for 30 minutes, add solution B dropwise to A under stirring. After the dropwise addition, sonicate for half an hour, transfer to a 75mL hydrothermal kettle, screw the lid on, and heat in an oven at a heating temperature of 200 degrees. React for 7 hours, cool down, pour off the supernatant, collect the solid below, wash twice with a mixture of ethanol and water, centrifuge, and dry to obtain NaGdF ₄ :Yb,Tm complexed with oleic acid ligand.

Examples 22-27

Take 2.5mL of 0.4M 78%Y(NO ₃ ) ₃ , 20%Yb(NO ₃ ) ₃ , 2%Er(NO ₃ ) ₃ aqueous solution in a beaker, add 14mL of deionized water and 16.5mL of methanol, normal Propanol, isopropanol, n-butanol, ethylene glycol or acetone, then add 73-30ml of oleic acid and 0.7g of NaOH, stir to form solution A. Weigh 504 mg of NaF and dissolve in 10 mL of water and 10 mL of methanol, n-propanol, isopropanol, n-butanol or acetone, and stir to form solution B. After stirring A for 30 minutes, add solution B dropwise to A under stirring. After the dropwise addition, sonicate for half an hour, transfer to a 75mL hydrothermal kettle, screw the lid on, and heat in an oven at a heating temperature of 200 degrees. React for 7 hours, cool down, pour off the supernatant, collect the solid below, wash twice with a mixture of ethanol and water, centrifuge, and dry to obtain NaYF ₄ :Yb,Er complexed with oleic acid ligand.

Example 28

Take 2.5mL of 0.4M 78%Y(NO ₃ ) ₃ , 20%Yb(NO ₃ ) ₃ , 2%Er(NO ₃ ) ₃ aqueous solution in a beaker, add 1.5mL of deionized water and 45mL of ethylene glycol , Then add 7ml of oleic acid and stir to form solution A. Weigh 504 mg of NaF and dissolve it in 5 mL of water, stir to form solution B. After stirring A for 30 minutes, add solution B dropwise to A under stirring. After the dropwise addition, sonicate for half an hour, transfer to a 75mL hydrothermal kettle, screw the lid on, and heat in an oven at a heating temperature of 200 degrees. React for 12 hours, cool down, pour off the supernatant, collect the solid below, wash twice with a mixture of ethanol and water, centrifuge, and dry to obtain NaYF ₄ :Yb,Er complexed with oleic acid ligand.

Claims (8)

1. high strength rare earth doping up-conversion luminescence nano material, it is characterized in that: described material is that ligand L is passed through the rare earth ion of coordination chemistry key in rear-earth-doped up-conversion luminescence nano material and is combined the nano material that forms, and described rear-earth-doped up-conversion luminescence nano material has following structure:

MNF _y:Yb ³⁺,Re

Wherein, M is selected from Na ⁺, Li ⁺, K ⁺, Mg ²⁺, Ca ²⁺And Ba ²⁺In a kind of; N is Y ³⁺, Gd ³⁺Or Lu ³⁺Y is 4 or 5; Re is Er ³⁺, Ho ³⁺Or Tm ³⁺

Described ligand L is organic compound take C1～C18 carbochain as skeleton, and described organic compound contains 1～6 substituting group, and described substituting group is selected from least a in carboxyl, hydroxyl and amino.

2. material according to claim 1, it is characterized in that: described ligand L is the organic compound with general formula I:

In formula, R ₁Be C ₁～C ₁₇Saturated or unsaturated alkyl; Hydroxyl or the amino C that replaces ₁～C ₁₇Saturated alkyl; Hydroxyl or the amino C that replaces ₁～C ₁₇Unsaturated alkyl, aryl.

3. material according to claim 1, it is characterized in that: described ligand L is the organic compound with general formula I I:

In formula, R ₂Be C ₁～C ₁₆Saturated or unsaturated alkyl; The C of hydroxyl, amino or carboxyl substituted ₁～C ₁₆Saturated alkyl; The C of hydroxyl, amino or carboxyl substituted ₁～C ₁₆Unsaturated alkyl, aryl.

4. material according to claim 1, it is characterized in that: described ligand L is butylamine, quadrol or triethylene tetramine.

5. material according to claim 2, it is characterized in that: described ligand L is propionic acid, 4-pentenoic acid, maleic acid, alpha-hydroxybutyric acid, L-Ala, oleic acid, phenylformic acid or Whitfield's ointment.

6. material according to claim 3, it is characterized in that: described ligand L is succinic acid, oxysuccinic acid, tartrate, phthalic acid, citric acid or ethylenediamine tetraacetic acid (EDTA).

7. according to claim 1～6 described materials of arbitrary claim, it is characterized in that: described doping up-conversion luminescence nano material is NaYF ₄: Yb, Er, NaYF ₄: Yb, Tm, LiYF ₄: Yb, Er, KYF ₄: Yb, Er, MgYF ₅: Yb, Er, CaYF ₅: Yb, Er, BaYF ₅: Yb, Er, NaGdF ₄: Yb, Er or NaLuF ₄: Yb, Er.

8. high strength rare earth doping up-conversion luminescence preparations of nanomaterials method, it is characterized in that: described method is hydro-thermal-organic solvent thermal synthesis method, according to target MNF _y: Yb ³⁺The Re compound is dissolved in rare earth ion source compound and ligand compound in reaction solvent, and wherein the mol ratio of rare earth element ion and ligand L compound is 2:1～1:100, adds NaOH, the mol ratio of NaOH and ligand L compound is 0:1～1:1, obtain solution A; Alkaline metal fluoride cpd is dissolved in reaction solvent, forms solution B; Add solution B in solution A, the mol ratio of fluorion and rare earth ion is 4～12, moves in reactor in 180～240 ℃ reaction 2～24h after mixing;

Wherein, reaction solvent is water-ethanol, water-methanol, water-Virahol, water-n-propyl alcohol, water-propyl carbinol or water-ethylene glycol solvent, and wherein the volume ratio of water and organic solvent is 2:1～1:5.

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