阅读说明：本技术 稀土掺杂氟化钇钠核壳结构纳米材料及其制备方法 (Rare earth doped sodium yttrium fluoride core-shell structure nano material and preparation method thereof ) 是由 权泽卫 邓克荣 于 2021-01-14 设计创作，主要内容包括：本发明提供一种稀土掺杂氟化钇钠核壳结构纳米材料,其化学通式为：NaY-((1-x))Ln-xF-4@NaAF-4,其中,Ln选自Y、Ho、Er、Tm、Gd、La中的一种或多种,0<x≤50mol％,A选自Yb、Y、Ho、Er、Tm、Gd、La中的一种或多种。本发明还提供该稀土掺杂氟化钇钠核壳结构纳米材料的制备方法。本发明的稀土掺杂氟化钇钠核壳结构纳米材料单分散性好,尺寸形貌均一,发光效率高,显示出在光学存储、照明显示、光学防伪和编码等领域潜在的应用前景。(The invention provides a rare earth doped sodium yttrium fluoride core-shell structure nano material, which has a chemical general formula as follows: NaY (1‑x) Ln x F 4 @NaAF 4 Wherein Ln is one or more selected from Y, Ho, Er, Tm, Gd and La, and 0<x is less than or equal to 50mol percent, A is selected from one or more of Yb, Y, Ho, Er, Tm, Gd and La. The invention also provides a preparation method of the rare earth doped sodium yttrium fluoride core-shell structure nano material. The rare earth doped sodium yttrium fluoride core-shell structure nano material has good monodispersity, uniform size and appearance and high luminous efficiency, and shows potential application prospects in the fields of optical storage, illumination display, optical anti-counterfeiting, encoding and the like.)

1. A rare earth doped sodium yttrium fluoride core-shell structure nano material is characterized in that the chemical general formula is as follows: NaY_(1-x)Ln_xF₄@NaAF₄Wherein Ln is one or more selected from Y, Ho, Er, Tm, Gd and La, and 0<x is less than or equal to 50mol percent, A is selected from one or more of Yb, Y, Ho, Er, Tm, Gd and La.

2. The rare earth doped sodium yttrium fluoride core-shell structure nanomaterial of claim 1, wherein the rare earth doped sodium yttrium fluoride core-shell structure nanomaterial is in a hexagonal phase structure, and the particle diameter range is 5-100 nm.

3. The rare earth doped sodium yttrium fluoride core-shell structured nanomaterial of claim 2, wherein the rare earth doped sodium yttrium fluoride core-shell structured nanomaterial is an oil soluble nanoparticle, the rare earth doped sodium yttrium fluoride core-shell structured nanomaterial is a rare earth doped sodium yttrium fluoride core-shell structured nanomaterial, and the rare earth doped sodium yttrium fluoride core-shell structured nanomaterial is selected from any one or more of the following nanoparticles: NaYF₄:5mol％Yb,0.5mol％[email protected]₄Nanoparticles, NaYF₄:20mol％Yb,2mol％[email protected]₄Nanoparticles, NaYF₄:18mol％,1mol％[email protected]₄Nanoparticles and NaYF₄:20mol％Yb,1mol％[email protected]₄And (3) nanoparticles.

4. A preparation method of a rare earth doped sodium yttrium fluoride core-shell structure nano material is characterized by comprising the following steps:

s1, preparing rare earth doped sodium yttrium fluoride nano material NaY_(1-x)Ln_xF₄The seed crystal is used as a core seed crystal, wherein Ln is selected from one or more of Y, Ho, Er, Tm, Gd and La, and 0<x≤50mol％；

S2, preparing a metal salt solution as a shell precursor solution, wherein the metal in the metal salt solution is selected from one or more of Na, Y, Yb, Ho, Er, Tm, Gd and La;

s3, adding the kernel seed crystal obtained in the step S1 into the shell precursor solution obtained in the step S2;

and S4, adding a methanol solution of ammonium fluoride into the mixed solution obtained in the step S3, and reacting to obtain the rare earth doped sodium yttrium fluoride core-shell structure nano material.

5. The method for preparing a rare earth doped sodium yttrium fluoride core-shell structured nanomaterial as claimed in claim 4, wherein in the step S2, the metal salt solution is any one of a halide solution, an acetate solution and a nitrate solution, wherein the acetate solution is selected from one or more of a sodium acetate solution, a yttrium acetate solution, an ytterbium acetate solution, an erbium acetate solution, a holmium acetate solution, a thulium acetate solution, a gadolinium acetate solution and a lanthanum acetate solution.

6. The method for preparing a rare earth doped sodium yttrium fluoride core-shell structure nanomaterial as claimed in claim 4, wherein the step S2 specifically comprises the following steps:

s21, dissolving a metal salt in a mixed solvent of oleic acid and octadecene to obtain a metal salt mixed solution, wherein the volume ratio of oleic acid to octadecene is 1-10: 1-100; and the number of the first and second groups,

and S22, under the protection of inert gas, heating the metal salt mixed solution obtained in the step S21 to 100-160 ℃, preserving heat for 0.5-1 h, and then cooling to 5-50 ℃ to obtain a clarified metal salt solution.

7. The preparation method of the rare earth doped sodium yttrium fluoride core-shell structure nanomaterial as claimed in claim 4, wherein in the step S3, the molar ratio of the core seed crystal to the shell precursor is 4: 1-1: 5.

8. The method for preparing a rare earth doped sodium yttrium fluoride core-shell structured nanomaterial according to claim 4, wherein in the step S4, the molar amount of ammonium fluoride in the methanol solution of ammonium fluoride is 4-4.2 times of the molar amount of metal salt in the metal salt solution.

9. The method for preparing a rare earth doped sodium yttrium fluoride core-shell structure nanomaterial according to claim 4, wherein in the step S4, the reaction temperature is 280-350 ℃ and the reaction time is 5-180 min.

Technical Field

The invention relates to the technical field of nano luminescent materials, in particular to a rare earth doped sodium yttrium fluoride core-shell structure nano material and a preparation method thereof.

Background

The rare earth doped up-conversion nanoparticles can convert near infrared light into visible light, and have the advantages of no background fluorescence, low toxicity, high light stability, deeper light penetration depth and the like, so that the rare earth doped up-conversion nanoparticles attract wide attention in various biological applications. The rare earth doped up-conversion nano material mainly comprises phosphate, vanadate, oxide, sulfide, fluoride and the like. The rare earth doped fluoride nano luminescent material has the characteristics of small phonon energy and high chemical stability, and has potential application value in the aspects of biological and medical detection. However, the up-conversion luminous efficiency of the existing rare earth doped sodium yttrium fluoride nano material is generally low, and the application of the nano material is limited.

Disclosure of Invention

The invention mainly aims to provide a rare earth doped sodium yttrium fluoride core-shell structure nano material, aiming at improving the up-conversion luminous efficiency of the rare earth doped sodium yttrium fluoride nano material.

In order to achieve the purpose, the invention provides a rare earth doped sodium yttrium fluoride core-shell structure nano material, which has a chemical general formula as follows: NaY_(1-x)Ln_xF₄@NaAF₄Wherein Ln is one or more selected from Y, Ho, Er, Tm, Gd and La, and 0<x is less than or equal to 50mol percent, A is selected from one or more of Yb, Y, Ho, Er, Tm, Gd and La.

Optionally, the rare earth doped sodium yttrium fluoride core-shell structure nano material is of a hexagonal phase structure, and the size range is 5-100 nm.

Optionally, the rare earth-doped sodium yttrium fluoride core-shell structure nano material is oil-soluble nano particles, the rare earth-doped sodium yttrium fluoride core-shell structure nano material is a rare earth-doped sodium yttrium fluoride core-shell structure nano material, and the rare earth-doped sodium yttrium fluoride core-shell structure nano material is selected from any one or more of the following nano particles: NaYF₄:5mol％Yb,0.5mol％[email protected]₄Nanoparticles, NaYF₄:20mol％Yb,2mol％[email protected]₄Nanoparticles, NaYF₄:18mol％,1mol％[email protected]₄Nanoparticles and NaYF₄:20mol％Yb,1mol％[email protected]₄And (3) nanoparticles.

The invention also provides a preparation method of the rare earth doped sodium yttrium fluoride core-shell structure nano material, which comprises the following steps:

s1, preparing rare earth doped sodium yttrium fluoride nano material NaY_(1-x)Ln_xF₄The seed crystal is used as a core seed crystal, wherein Ln is selected from one or more of Y, Ho, Er, Tm, Gd and LaSeed, 0<x≤50mol％；

S2, preparing a metal salt solution as a shell precursor solution, wherein the metal in the metal salt solution is selected from one or more of Na, Y, Yb, Ho, Er, Tm, Gd and La;

s3, adding the kernel seed crystal obtained in the step S1 into the shell precursor solution obtained in the step S2;

s4, adding a methanol solution of ammonium fluoride into the mixed solution obtained in the step S3, and reacting to obtain the rare earth doped sodium yttrium fluoride core-shell structure nano material; and the number of the first and second groups,

s5, taking the rare earth doped sodium yttrium fluoride core-shell structure nano material as an inner core seed crystal, and repeating the steps S2-S4 to obtain the rare earth doped sodium yttrium fluoride multi-shell layer core-shell structure nano material.

Further, in step S2, the metal salt solution is any one of a halide solution, an acetate solution and a nitrate solution, wherein the acetate solution is selected from one or more of a sodium acetate solution, a yttrium acetate solution, an ytterbium acetate solution, an erbium acetate solution, a holmium acetate solution, a thulium acetate solution, a gadolinium acetate solution and a lanthanum acetate solution.

Further, the step S2 specifically includes the following steps:

s21, dissolving a metal salt in a mixed solvent of oleic acid and octadecene to obtain a metal salt mixed solution, wherein the volume ratio of oleic acid to octadecene is 1-10: 1-100; and the number of the first and second groups,

and S22, under the protection of inert gas, heating the metal salt mixed solution obtained in the step S21 to 100-160 ℃, preserving heat for 0.5-1 h, and then cooling to 5-50 ℃ to obtain a clarified metal salt solution.

Further, in the step S3, the molar ratio of the core seed crystal to the shell precursor is 4: 1-1: 5.

Further, in the step S4, the molar amount of ammonium fluoride in the methanol solution of ammonium fluoride is 4 to 4.2 times of the molar amount of the metal salt in the metal salt solution.

Further, in the step S4, the reaction temperature is 280 to 350 ℃, and the reaction time is 5 to 180 min.

According to the technical scheme, the rare earth doped sodium yttrium fluoride nano material is used as the inner core for epitaxial growth, and the core-shell structure nano material with uniform coating is obtained. According to the spectrum test result, the luminous efficiency of the coated nano material is greatly improved, and the fluorescence quantum yield is correspondingly improved. In addition, the nano material has good monodispersity, uniform size and appearance and high luminous efficiency, and shows potential application prospects in the fields of optical storage, illumination display, optical anti-counterfeiting, encoding and the like.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.

NaYF obtained in figure 1, comparative example 1 and example 1₄5 mol% Yb,0.5 mol% Er nanoparticles and NaYF₄:5mol％Yb,0.5mol％[email protected]₄Powder diffraction pattern of nanoparticles.

FIG. 2, (a) NaYF obtained in comparative example 1₄20 mol% Yb,2 mol% Er nanoparticles, (b) NaYF obtained in example 1₄:20mol％Yb,2mol％[email protected]₄Transmission electron microscopy of nanoparticles.

NaYF obtained in FIG. 3, comparative example 1 and example 1₄5 mol% Yb,0.5 mol% Er nanoparticles and NaYF₄:5mol％Yb,0.5mol％[email protected]₄The upconversion emission spectrum of the nanoparticles (excitation 980 nm).

NaYF obtained in FIG. 4, comparative example 2 and example 2₄20 mol% Yb,2 mol% Er nanoparticles and NaYF₄:20mol％Yb,2mol％[email protected]₄Powder diffraction pattern of nanoparticles.

NaYF obtained in FIG. 5, comparative example 2 and example 2₄20 mol% Yb,2 mol% Er nanoparticles and NaYF₄:20mol％Yb,2mol％[email protected]₄Up-conversion of nanoparticlesEmission spectrum (excitation 980 nm).

NaYF obtained in FIG. 6, example 1 and example 2₄:5mol％Yb,0.5mol％[email protected]₄Nanoparticles and NaYF₄:20mol％Yb,2mol％[email protected]₄Upconversion emission spectrum (excitation 980 nm).

NaYF obtained in FIG. 7, comparative example 3 and example 3₄18 mol%, 1 mol% Tm nanoparticles and NaYF₄:18mol％,1mol％[email protected]₄Powder diffraction pattern of nanoparticles.

FIG. 8, (a) NaYF obtained in comparative example 3₄18 mol%, 1 mol% Tm nanoparticles, (b) 18 mol%, 1 mol% Tm @ NaYF, NaYF4 obtained in example 3₄Transmission electron microscopy of nanoparticles.

NaYF obtained in FIG. 9, comparative example 4 and example 4₄20 mol% Yb,1 mol% Ho nanoparticles and NaYF₄:20mol％Yb,1mol％[email protected]₄Powder diffraction pattern of nanoparticles.

FIG. 10, (a) NaYF of comparative examples 4 to 4₄20 mol% Yb,1 mol% Ho nanoparticles, (b) NaYF obtained in example 4₄:20mol％Yb,1mol％[email protected]₄Transmission electron microscopy of nanoparticle images.

The implementation, functional features and advantages of the objects of the present invention will be further explained with reference to the accompanying drawings.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

If there is a description of "first", "second", etc. in an embodiment of the present invention, the description of "first", "second", etc. is for descriptive purposes only and is not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In addition, the meaning of "and/or" appearing throughout is to include three juxtapositions, exemplified by "A and/or B," including either the A or B arrangement, or both A and B satisfied arrangement. In addition, technical solutions between various embodiments may be combined with each other, but must be realized by a person skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination should not be considered to exist, and is not within the protection scope of the present invention.

The embodiment of the invention provides a rare earth doped sodium yttrium fluoride core-shell structure nano material, which has a chemical general formula as follows: NaY_(1-x)Ln_xF₄@NaAF₄Wherein Ln is one or more selected from Y, Ho, Er, Tm, Gd and La, and 0<x is less than or equal to 50mol percent, A is selected from one or more of Yb, Y, Ho, Er, Tm, Gd and La.

In some embodiments of the invention, an improved high-temperature coprecipitation method is adopted to synthesize a rare earth doped sodium yttrium fluoride nano material, the rare earth doped sodium yttrium fluoride nano material is used as an inner core for epitaxial growth to prepare a uniformly coated rare earth doped sodium yttrium fluoride core-shell structure nano material, and the rare earth doped sodium yttrium fluoride multi-shell core-shell structure nano material is prepared after further coating.

According to the embodiment of the invention, the rare earth doped sodium yttrium fluoride nanometer material, the rare earth doped sodium yttrium fluoride core-shell structure nanometer material and the rare earth doped sodium yttrium fluoride multi-shell layer core-shell structure nanometer material are in hexagonal phase structures, are uniform in size and appearance, and have the size range of 5-100 nm.

According to the embodiment of the invention, the rare earth doped sodium yttrium fluoride nano material, the rare earth doped sodium yttrium fluoride core-shell structure nano material and the rare earth doped sodium yttrium fluoride multi-shell layer core-shell structure nano material are oil-soluble nano particles.

According to the embodiment of the invention, the rare earth doped sodium yttrium fluoride nano material used as the inner core can be selected from one or more of the following nanoparticles: NaYF₄:5mol％Yb,0.5mol％Er nanoparticles, NaYF₄20 mol% of Yb,2 mol% of Er nano particles and NaYF₄18 mol%, 1 mol% Tm nanoparticles and NaYF₄20 mol% Yb,1 mol% Ho nanoparticles.

The rare earth doped sodium yttrium fluoride core-shell structure nano material is selected from any one or more of the following nano particles: NaYF₄:5mol％Yb,0.5mol％[email protected]₄Nanoparticles, NaYF₄:20mol％Yb,2mol％[email protected]₄Nanoparticles, NaYF₄:18mol％,1mol％[email protected]₄Nanoparticles and NaYF₄:20mol％Yb,1mol％[email protected]₄And (3) nanoparticles.

The embodiment of the invention also provides a preparation method of the rare earth doped sodium yttrium fluoride core-shell structure nano material, which comprises the following steps:

s1, preparing rare earth doped sodium yttrium fluoride nano material NaY_(1-x)Ln_xF₄The seed crystal is used as a core seed crystal, wherein Ln is selected from one or more of Y, Ho, Er, Tm, Gd and La, and 0<x≤50mol％；

S2, preparing a metal salt solution as a shell precursor solution, wherein the metal in the metal salt solution is selected from one or more of Na, Y, Yb, Ho, Er, Tm, Gd and La;

s3, adding the kernel seed crystal obtained in the step S1 into the shell precursor solution obtained in the step S2;

and S4, adding a methanol solution of ammonium fluoride into the mixed solution obtained in the step S3, and reacting to obtain the rare earth doped sodium yttrium fluoride core-shell structure nano material.

Further, the step S1 specifically includes the following steps:

s11, preparing a metal salt solution, wherein the metal in the metal salt solution is selected from one or more of Na, Y, Yb, Ho, Er, Tm, Gd and La;

s12, adding a methanol solution of ammonium fluoride into the solution obtained in the step S11, and reacting to obtain the rare earth doped sodium yttrium fluoride nano material NaY_(1-x)Ln_xF₄；

Wherein the metal salt solution can be halide solution, acetate solution or nitrate solutionPreferably, a halide solution or an acetate solution, and more preferably an acetate solution. Wherein the acetate solution is selected from one or more of sodium acetate, yttrium acetate, ytterbium acetate, erbium acetate, holmium acetate, thulium acetate, gadolinium acetate and lanthanum acetate. The dosage of the metal salt in the metal salt solution conforms to NaY_(1-x)Ln_xF₄Wherein x and Ln have the same meanings as defined above.

According to the embodiment of the present invention, the step S11 specifically includes: dissolving a metal salt in a solvent R at 5-50 ℃ (such as room temperature), heating to 100 ℃ and 160 ℃ under the protection of inert gas, preserving the temperature for 30min, and then cooling to 5-50 ℃ (such as room temperature) to obtain a clear solution. Wherein, the solvent R is selected from a mixed solution of oleic acid (or oleylamine) and octadecene, the volume ratio of the oleic acid to the octadecene is 1-10: 1-100, preferably 2-6: 2-50, and for example, the mixed solution of oleic acid and octadecene with the volume ratio of 2:3 is used as the solvent.

According to an embodiment of the present invention, in the step S12, the molar amount of ammonium fluoride in the methanol solution of ammonium fluoride may be 4 times the molar amount of sodium salt in the metal sodium salt solution used in the step S11.

According to an embodiment of the present invention, in the step S12, the reaction temperature is 280-350 ℃, and the reaction time is 5-180 min.

In step S2, the metal salt solution is any one of halide solution, acetate solution and nitrate solution, wherein the acetate solution is selected from one or more of sodium acetate solution, yttrium acetate solution, ytterbium acetate solution, erbium acetate solution, holmium acetate solution, thulium acetate solution, gadolinium acetate solution and lanthanum acetate solution.

The step S2 specifically includes the following steps:

s21, dissolving a metal salt in a mixed solvent of oleic acid (or oleylamine) and octadecene to obtain a metal salt mixed solution; and the number of the first and second groups,

and S22, under the protection of inert gas, heating the metal salt mixed solution obtained in the step S21 to 100-160 ℃, preserving the heat for 30-XXmin, and then cooling to 5-50 ℃ to obtain a clarified metal salt solution.

In the step S21, the volume ratio of oleic acid (or oleylamine) to octadecene is 1-10: 1-100, preferably 2-6: 2-50.

In the step S3, the molar ratio of the kernel seed crystal to the shell precursor is 4: 1-1: 5.

In the step S4, the molar weight of ammonium fluoride in the methanol solution of ammonium fluoride is 4 to 4.2 times of the molar weight of the metal salt in the metal salt solution.

In the step S4, the reaction temperature is 280-350 ℃, and the reaction time is 5-180 min.

Also, in the step S51, the metal salt solution is any one of a halide solution, an acetate solution and a nitrate solution, wherein the acetate solution is selected from one or more of a sodium acetate solution, a yttrium acetate solution, an ytterbium acetate solution, an erbium acetate solution, a holmium acetate solution, a thulium acetate solution, a gadolinium acetate solution and a lanthanum acetate solution.

The step S52 specifically includes the following steps:

s521, dissolving a metal salt in a mixed solvent of oleic acid (or oleylamine) and octadecene to obtain a metal salt mixed solution; and the number of the first and second groups,

and S522, under the protection of inert gas, heating the metal salt mixed solution obtained in the step S21 to 100-160 ℃, preserving heat for 0.5-1 h, and then cooling to 5-50 ℃ to obtain a clarified metal salt solution.

In the step S521, the volume ratio of oleic acid (or oleylamine) to octadecene is 1-10: 1-100, preferably 2-6: 2-50.

In the step S53, the molar ratio of the kernel seed crystal to the shell precursor is 4: 1-1: 5.

In the step S54, the molar weight of ammonium fluoride in the methanol solution of ammonium fluoride is 4 to 4.2 times of the molar weight of the metal salt in the metal salt solution.

In the step S55, the reaction temperature is 280-350 ℃, and the reaction time is 5-180 min.

The following will combine specific examples and comparative examples to further illustrate the rare earth doped sodium yttrium fluoride core-shell structured nanomaterial of the present invention. It is to be understood that the following description is only exemplary, and not restrictive of the invention.

Unless otherwise indicated, the starting materials and reagents used in the examples are all commercially available materials or prepared by known methods.

Comparative example 1: NaYF₄5mol percent of Yb and 0.5mol percent of Er nano-particles. 0.005mmol of Er (CH) was weighed₃COO)₃·4H₂O、0.05mmol Yb(CH₃COO)₃·4H₂O and 0.945mmol Y (CH)₃COO)₃·4H₂O, then adding 8mL of oleic acid and 12mL of octadecene, introducing nitrogen, heating to 120 ℃, preserving heat for 30 minutes to form a transparent solution A, and then cooling to room temperature; 2.25mmol NaOH and 4mmol NH were weighed₄Dissolving the mixture in 10mL of methanol, dropwise adding the mixture into the solution A, continuously stirring for 10min to fully mix the mixture, heating to 60 ℃, and preserving the temperature for 30min to form a transparent solution B; heating to 280 ℃, preserving heat for 1h, and cooling to room temperature; adding 20mL of ethanol for precipitation separation and washing for a plurality of times to obtain the oil-soluble NaYF₄5 mol% of Yb and 0.5 mol% of Er nano-particles.

Example 1: NaYF₄:5mol％Yb,0.5mol％[email protected]₄And (4) preparing nanoparticles. 0.005mmol of Er (CH) was weighed₃COO)₃·4H₂O、0.05mmol Yb(CH₃COO)₃·4H₂O and 0.945mmol Y (CH)₃COO)₃·4H₂O, then adding 8mL of oleic acid and 12mL of octadecene, introducing nitrogen, heating to 120 ℃, preserving heat for 30 minutes to form a transparent solution A, and then cooling to room temperature; NaOH and 4mmol of NH were weighed₄Dissolving the mixture in 10mL of methanol, dropwise adding the mixture into the solution A, continuously stirring for 10min to fully mix the mixture, heating to 60 ℃, and preserving the temperature for 30min to form a transparent solution B; heating to 280 ℃, preserving heat for 1h, and cooling to room temperature; adding 20mL of ethanol for precipitation separation and washing for a plurality of times to obtain the oil-soluble NaYF₄5 mol% of Yb and 0.5 mol% of Er nano-particles. Mixing oil soluble NaYF₄5mol percent of Yb and 0.5mol percent of Er nano particles are taken as kernel seed crystals to carry out core-shell coating. Weighing 1mmol of Y (CH)₃COO)₃·4H₂O, then adding 8mL of oleic acid and 12mL of octadecene, introducing nitrogen, heating to 120 ℃ and keepingWarming for 30 minutes to form a clear solution C, adding 1mmol NaYF₄:5mol％Yb,0.5mol％[email protected]₄And (4) carrying out kernel seed crystal. Stirring for 10min, weighing 2.25mmol NaOH and 4mmol NH₄Dissolving the mixture in 10mL of methanol, dropwise adding the mixture into the solution C, continuously stirring for 10min to fully mix the mixture, heating to 60 ℃, and preserving the temperature for 30min to form a transparent solution D; heating to 280 ℃, preserving heat for 1h, and cooling to room temperature; adding 20mL of ethanol for precipitation separation and washing for a plurality of times to obtain the oil-soluble NaYF₄:5mol％Yb,0.5mol％[email protected]₄And (3) nanoparticles.

Comparative example 2: NaYF₄20mol percent of Yb and 2mol percent of Er nano-particles. 0.02mmol of Er (CH) was weighed₃COO)₃·4H₂O、0.2mmolYb(CH₃COO)₃·4H₂O and 0.78mmol Y (CH)₃COO)₃·4H₂O, then adding 8mL of oleic acid and 12mL of octadecene, introducing nitrogen, heating to 120 ℃, preserving heat for 30 minutes to form a transparent solution A, and then cooling to room temperature; 2.25mmol NaOH and 4mmol NH were weighed₄Dissolving the mixture in 10mL of methanol, dropwise adding the mixture into the solution A, continuously stirring for 10min to fully mix the mixture, heating to 60 ℃, and preserving the temperature for 30min to form a transparent solution B; heating to 280 ℃, preserving heat for 1h, and cooling to room temperature; adding 20mL of ethanol for precipitation separation and washing for a plurality of times to obtain the oil-soluble NaYF₄20 mol% of Yb and 2 mol% of Er nano-particles.

Example 2: NaYF₄:20mol％Yb,2mol％[email protected]₄And (4) preparing nanoparticles. 0.02mmol of Er (CH) was weighed₃COO)₃·4H₂O、0.2mmol Yb(CH₃COO)₃·4H₂O and 0.78mmol Y (CH)₃COO)₃·4H₂O, then adding 8mL of oleic acid and 12mL of octadecene, introducing nitrogen, heating to 120 ℃, preserving heat for 30 minutes to form a transparent solution A, and then cooling to room temperature; 2.25mol NaOH and 4mmol NH were weighed₄Dissolving the mixture in 10mL of methanol, dropwise adding the mixture into the solution A, continuously stirring for 10min to fully mix the mixture, heating to 60 ℃, and preserving the temperature for 30min to form a transparent solution B; heating to 280 ℃, preserving heat for 1h, and cooling to room temperature; adding 20mL of ethanol for precipitation separation and washing for a plurality of times to obtain the oil-soluble NaYF₄20 mol% of Yb and 2 mol% of Er nano-particles. Mixing oil soluble NaYF₄20mol percent of Yb and 2mol percent of Er nano particles are taken as kernel seed crystals to carry out core-shell coating. Weighing 1mmol of Y (CH)₃COO)₃·4H₂O, then adding 8mL of oleic acid and 12mL of octadecene, introducing nitrogen, heating to 120 ℃, preserving heat for 30 minutes to form a transparent solution C, and adding 1mmol of NaYF₄20 mol% Yb and 2 mol% Er core seed crystal. Stirring for 10min, weighing 2.25mmol NaOH and 4mmol NH₄Dissolving the mixture in 10mL of methanol, dropwise adding the mixture into the solution C, continuously stirring for 10min to fully mix the mixture, heating to 60 ℃, and preserving the temperature for 30min to form a transparent solution D; heating to 280 ℃, preserving heat for 1h, and cooling to room temperature; adding 20mL of ethanol for precipitation separation and washing for a plurality of times to obtain the oil-soluble NaYF₄:20mol％Yb,2mol％[email protected]₄And (3) nanoparticles.

Comparative example 3: NaYF₄18 mol%, 1 mol% Tm nanoparticles. Weighing 0.01mmol Tm (CH)₃COO)₃·4H₂O、0.18mmolYb(CH₃COO)₃·4H₂O and 0.81mmol Y (CH)₃COO)₃·4H₂O, then adding 8mL of oleic acid and 12mL of octadecene, introducing nitrogen, heating to 120 ℃, preserving heat for 30 minutes to form a transparent solution A, and then cooling to room temperature; 2.25mmol NaOH and 4mmol NH were weighed₄Dissolving the mixture in 10mL of methanol, dropwise adding the mixture into the solution A, continuously stirring for 10min to fully mix the mixture, heating to 60 ℃, and preserving the temperature for 30min to form a transparent solution B; heating to 280 ℃, preserving heat for 1h, and cooling to room temperature; adding 20mL of ethanol for precipitation separation and washing for a plurality of times to obtain the oil-soluble NaYF₄18 mol% Yb,1 mol% Tm nanoparticles.

Example 3: NaYF₄:18mol％,1mol％[email protected]₄And (4) preparing nanoparticles. Weighing 0.01mmol Tm (CH)₃COO)₃·4H₂O、0.18mmol Yb(CH₃COO)₃·4H₂O and 0.79mmol Y (CH)₃COO)₃·4H₂O, then adding 8mL of oleic acid and 12mL of octadecene, introducing nitrogen, heating to 120 ℃, preserving heat for 30 minutes to form a transparent solution A, and then cooling to room temperature; 2.25mol NaOH and 4mmol NH were weighed₄Dissolving the mixture in 10mL of methanol, dropwise adding the mixture into the solution A, continuously stirring for 10min to fully mix the mixture, heating to 60 ℃, and preserving the temperature for 30min to form a transparent solution B; heating to 280 ℃, preserving heat for 1h, and cooling to room temperature; adding 20mL of ethanol for precipitation separation and washing for a plurality of times to obtain the oil-soluble NaYF₄18 mol%, 1 mol% Tm nanoparticles. Mixing oil soluble NaYF₄18mol percent of Tm nano particles and 1mol percent of Tm nano particles are taken as kernel seed crystals to carry out core-shell coating. Weighing 1mmol of Y (CH)₃COO)₃·4H₂O, then adding 8mL of oleic acid and 12mL of octadecene, introducing nitrogen, heating to 120 ℃, preserving heat for 30 minutes to form a transparent solution C, and adding 1mmol of NaYF₄18 mol%, 1 mol% Tm core seed crystal. Stirring for 10min, weighing 2.25mmol NaOH and 4mmol NH₄Dissolving the mixture in 10mL of methanol, dropwise adding the mixture into the solution C, continuously stirring for 10min to fully mix the mixture, heating to 60 ℃, and preserving the temperature for 30min to form a transparent solution D; heating to 280 ℃, preserving heat for 1h, and cooling to room temperature; adding 20mL of ethanol for precipitation separation and washing for a plurality of times to obtain the oil-soluble NaYF₄:18mol％,1mol％[email protected]₄And (3) nanoparticles.

Comparative example 4: NaYF₄Preparation of 20 mol% Yb,1 mol% Ho nanoparticles. 0.01mmol of Ho (CH) was weighed₃COO)₃·4H₂O、0.2mmolYb(CH₃COO)₃·4H₂O and 0.79mmol Y (CH)₃COO)₃·4H₂O, then adding 8mL of oleic acid and 12mL of octadecene, introducing nitrogen, heating to 120 ℃, preserving heat for 30 minutes to form a transparent solution A, and then cooling to room temperature; 2.25mmol NaOH and 4mmol NH were weighed₄Dissolving the mixture in 10mL of methanol, dropwise adding the mixture into the solution A, continuously stirring for 10min to fully mix the mixture, heating to 60 ℃, and preserving the temperature for 30min to form a transparent solution B; heating to 280 ℃, preserving heat for 1h, and cooling to room temperature; adding 20mL of ethanol for precipitation separation and washing for several times; adding 20mL of ethanol for precipitation separation and washing for several times to obtain the oil-soluble NaYF₄20 mol% Yb,1 mol% Ho nanoparticles.

Example 4: NaYF₄:20mol％Yb,1mol％[email protected]₄And (4) preparing nanoparticles. 0.01mmol of Ho (CH) was weighed₃COO)₃·4H₂O、0.2mmolYb(CH₃COO)₃·4H₂O and 0.79mmol Y (CH)₃COO)₃·4H₂O, then adding 8mL of oleic acid and 12mL of octadecene, introducing nitrogen, heating to 120 ℃, preserving heat for 30 minutes to form a transparent solution A, and then cooling to room temperature; 2.25mmol NaOH and 4mmol NH were weighed₄Dissolving the mixture in 10mL of methanol, dropwise adding the mixture into the solution A, continuously stirring for 10min to fully mix the mixture, heating to 60 ℃, and preserving the temperature for 30min to form a transparent solution B; heating to 280 ℃, preserving heat for 1h, and cooling to room temperature; adding 20mL of ethanol for precipitation separation and washing for a plurality of times to obtain the oil-soluble NaYF₄20 mol% Yb,1 mol% Ho nanoparticles. Mixing oil soluble NaYF₄20mol percent of Yb and 1mol percent of Ho nano particles are taken as kernel seed crystals to carry out core-shell coating. Weighing 1mmol of Y (CH)₃COO)₃·4H₂O, then adding 8mL of oleic acid and 12mL of octadecene, introducing nitrogen, heating to 120 ℃, preserving heat for 30 minutes to form a transparent solution C, and adding 1mmol of NaYF₄20 mol% Yb,1 mol% Ho core seed crystal. Stirring for 10min, weighing 2.25mmol NaOH and 4mmol NH₄Dissolving the mixture in 10mL of methanol, dropwise adding the mixture into the solution C, continuously stirring for 10min to fully mix the mixture, heating to 60 ℃, and preserving the temperature for 30min to form a transparent solution D; heating to 280 ℃, preserving heat for 1h, and cooling to room temperature; adding 20mL of ethanol for precipitation separation and washing for a plurality of times to obtain the oil-soluble NaYF₄:20mol％Yb,1mol％[email protected]₄And (3) nanoparticles.

The testing process comprises the following steps: the products obtained in the above examples and comparative examples were characterized by powder diffraction using a SmartLab apparatus manufactured by Nippon Kogyo Co., Ltd. (Rigaku) and a copper target radiation wavelength of λ 0.154187 nm.

The products obtained in the above examples and comparative examples were examined by transmission electron microscopy using an instrument type HT7700, manufactured by Hitachi (Hitachi).

The products obtained in the above examples and comparative examples were characterized by their upconversion emission spectra (excitation 980nm) using a Scientific FluoroMax-4 instrument manufactured by HORIBA (HORIBA).

As shown in FIG. 1, from the comparative exampleThe powder diffraction patterns of the products obtained from example 1 and example 1 respectively can be seen, NaYF₄5 mol% Yb,0.5 mol% Er nanoparticles and NaYF₄:5mol％Yb,0.5mol％[email protected]₄Nanoparticles have all been successfully synthesized.

As shown in FIG. 2, from the transmission electron micrographs of the products obtained in comparative example 1 and example 1, respectively, NaYF can be seen₄:5mol％Yb,0.5mol％[email protected]₄The size of the nano particles is obviously larger than NaYF₄5 mol% Yb,0.5 mol% Er nanoparticles due to the size of the NaYF₄:5mol％Yb,0.5mol％[email protected]₄The nanoparticles are made of NaYF₄5 mol% Yb and 0.5 mol% Er nano particles are taken as kernel seed crystals and then coated with a layer of shell, which also indicates that the rare earth doped sodium yttrium fluoride core-shell structure nano material with uniform coating can be prepared by epitaxial growth on the basis of taking the rare earth doped sodium yttrium fluoride nano material as the kernel.

As shown in FIG. 3, NaYF can be seen from the up-conversion emission spectra of the products obtained in comparative example 1 and example 1, respectively₄:5mol％Yb,0.5mol％[email protected]₄The up-conversion luminous efficiency of the nano particles is obviously higher than that of NaYF₄Compared with the uncoated rare earth doped sodium yttrium fluoride nano material, the coated rare earth doped sodium yttrium fluoride core-shell structure nano material has the advantage that the luminous efficiency can be greatly improved.

As shown in FIG. 4, NaYF can be seen from the powder diffraction patterns of the products obtained in comparative example 2 and example 2, respectively₄20 mol% Yb,2 mol% Er nanoparticles and NaYF₄:20mol％Yb,2mol％[email protected]₄Nanoparticles have all been successfully synthesized.

As shown in FIG. 5, NaYF can be seen from the up-conversion emission spectra of the products obtained in comparative example 2 and example 2, respectively₄:20mol％Yb,2mol％[email protected]₄The up-conversion luminous efficiency of the nano particles is obviously higher than that of NaYF₄20 mol% Yb and 2 mol% Er nano particles, which shows that compared with the uncoated rare earth doped sodium yttrium fluoride nano material, the luminous efficiency of the coated rare earth doped sodium yttrium fluoride core-shell structure nano material can be greatly improved.

As shown in FIG. 6, NaYF can be seen from the up-conversion emission spectra of the products obtained in example 1 and example 2, respectively₄:20mol％Yb,2mol％[email protected]₄The up-conversion luminous efficiency of the nano particles is obviously higher than that of NaYF₄:5mol％Yb,0.5mol％[email protected]₄And the nano particles show that in the rare earth doped sodium yttrium fluoride core-shell structure nano material, the higher the doping proportion of the rare earth element is, the higher the up-conversion luminous efficiency is.

As shown in FIG. 7, NaYF can be seen from the powder diffraction patterns of the products obtained in comparative example 3 and example 3, respectively₄18 mol%, 1 mol% Tm nanoparticles and NaYF₄:18mol％,1mol％[email protected]₄Nanoparticles have all been successfully synthesized.

As shown in FIG. 8, from the transmission electron micrographs of the products obtained in comparative example 3 and example 3, respectively, NaYF4:18 mol%, 1 mol% Tm @ NaYF₄The size of the nano particles is obviously larger than NaYF₄18 mol%, 1 mol% Tm nanoparticles size due to NaYF4:18 mol%, 1 mol% Tm @ NaYF₄The nanoparticles are made of NaYF₄18mol percent of Tm nano particles with the concentration of 1mol percent are taken as seed crystals of a core and then coated with a layer of shell, which also indicates that the rare earth doped sodium yttrium fluoride nano material with uniform coating can be prepared by epitaxial growth on the basis of taking the rare earth doped sodium yttrium fluoride nano material as the core.

As shown in FIG. 9, NaYF can be seen from the powder diffraction patterns of the products obtained in comparative example 4 and example 4, respectively₄20 mol% Yb,1 mol% Ho nanoparticles and NaYF₄:20mol％Yb,1mol％[email protected]₄Nanoparticles have all been successfully synthesized.

As shown in FIG. 10, from the transmission electron micrographs of the products obtained in comparative example 3 and example 3, respectively, NaYF can be seen₄:20mol％Yb,1mol％[email protected]₄The size of the nano particles is obviously larger than NaYF₄20 mol% Yb,1 mol% Ho nanoparticles size, due to NaYF₄:20mol％Yb,1mol％[email protected]₄The nanoparticles are made of NaYF₄20 mol% Yb and 1 mol% Ho nano-particles are used as seed crystals of a kernel and then coated with a shell layer to formThe fact that the rare earth doped sodium yttrium fluoride core-shell structure nano material with uniform coating can be prepared by epitaxial growth on the basis of taking the rare earth doped sodium yttrium fluoride nano material as the core is also demonstrated.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention, and all modifications and equivalents of the present invention, which are made by the contents of the present specification and the accompanying drawings, or directly/indirectly applied to other related technical fields, are included in the scope of the present invention.