CN104164233A - Preparation method of core-shell-structured rare earth nanoparticles - Google Patents

Abstract

The invention discloses a preparation method of core-shell-structured rare earth nanoparticles. The method comprises the following steps: mixing gadolinium trichloride with terbium trichloride with polyol as a solvent to completely dissolve gadolinium trichloride and terbium trichloride, adding a sodium hydroxide solution, and carrying out a synthesis reaction to obtain magnetic and luminiferous Tb<3+>-doped gadolinium oxide nanoparticles; and coating the surfaces of the gadolinium oxide nanoparticles with a polysiloxane layer in order to obtain the core-shell-structured rare earth nanoparticles. The nanoparticles prepared in the invention have the advantages of stable performances, good dispersibility, and control of the dimension of the particles through changing relevant parameters, and have important effects on the sending and detection of biological molecules as a novel biological probe in biosensors.

Description

Preparation method of rare earth nanoparticles with core-shell structure

technical field

The invention relates to the field of synthesis of nanomaterials, in particular to a method for preparing rare earth oxide nanoparticles with a core-shell structure. the

Background technique

Nanoparticles with core-shell structure have attracted people's attention because they can coat another layer of shell on the outside of the nanocrystalline core to realize the functional recombination of the core and the shell. Since the core in the core-shell nanoparticle is covered by the shell layer, it can not be disturbed or reduced by the surrounding environment, which makes the excellent performance of the core more remarkable. In recent years, the preparation and properties of organic-inorganic core-shell structure materials have attracted more and more attention, because organic-inorganic core-shell structure materials have the advantages of both organic materials and inorganic materials. However, due to the poor affinity between organic and inorganic substances, the preparation of organic-inorganic core-shell nanoparticles is not easy, and special preparation strategies must be adopted. Currently used preparation methods include suspension polymerization, dispersion polymerization, soap-free polymerization, emulsion polymerization, chemical co-precipitation and so on. The core-shell nanoparticles prepared by these methods have the problem of poor stability, and rare earth oxides with special properties (optical, magnetic) and doping as the core preparation technology are rarely reported. the

Contents of the invention

The purpose of the present invention is to provide a method for preparing rare earth oxide nanoparticles with a core-shell structure, the method is simple and easy to operate, and the prepared nanoparticles with a core-shell structure have stable structure, good dispersibility, and have fluorescence and magnetic properties. Overcome the deficiencies of the prior art. the

The present invention is achieved in this way: the preparation method of rare earth nanoparticles with a core-shell structure uses polyhydric alcohol as a solvent, mixes gadolinium trichloride and terbium trichloride to completely dissolve gadolinium trichloride and terbium trichloride, and then adds Sodium hydroxide solution is used for synthesis reaction to obtain magnetic and luminescent gadolinium oxide nanoparticles doped with Tb ³⁺ ; then the polysiloxane layer is coated on the surface of the gadolinium oxide nanoparticles to obtain rare earth nanoparticles with core-shell structure .

The molar ratio of gadolinium trichloride to terbium trichloride mixed is 95:5; the molar ratio of added sodium hydroxide to gadolinium trichloride is 3:1. the

The coating solution used in the coating polysiloxane layer includes coating solution S1 and coating solution S2; coating solution S1 is a mixed solution of tetraethyl silicate and 3-aminopropyltriethoxysilane , the molar ratio of tetraethyl silicate to 3-aminopropyltriethoxysilane is 4:6; coating solution S2 is a mixed solution of distilled water, triethylamine and diethylene glycol, distilled water, triethylamine and diethylene glycol The molar ratio of glycol is 35:1:37; then, under the condition of avoiding light and 40°C, 30% of the coating solution S1 is added by volume percentage to the solution containing gadolinium oxide nanoparticles doped with Tb ³⁺ In the colloidal transparent solution, add 30% coating solution S2 after 1 hour, add the remaining coating solution S1 after 1 hour, add the remaining coating solution S2 after another 1 hour, and complete the reaction after stirring for 48 hours Coating with polysiloxane layer.

The time for adding the sodium hydroxide solution to carry out the synthesis reaction is more than 6 hours. the

Described polyhydric alcohol is diethylene glycol. the

Based on the idea of improving the dispersibility and stability of the core-shell structure nanoparticles, effectively controlling the size of the nanoparticles and improving its detection signal, the present invention adopts the polyol method to prepare the core-shell structure Gd ₂ O ₃ /SiO _x nanoparticles, in proportion Mix gadolinium trichloride (GdCl ₃ ) and terbium trichloride (TbCl ₃ ), add an appropriate amount of diethylene glycol as a solvent, and then add NaOH solution to carry out the synthesis reaction. In the present invention, diethylene glycol is used as a solvent instead of water because diethylene glycol has good dispersibility and avoids the generation of sodium hydroxide when water is used as a solvent to ensure the yield of nanoparticles. The nano particles prepared by the invention can be stably dispersed in the solvent, have uniform size, and can be stored for a long time without agglomeration.

In order to further functionalize the prepared rare earth oxide nanoparticles doped with luminescent lanthanide ions, it is necessary to wrap organic matter on its surface, and use the functional groups of the organic layer to connect with other biomolecules to realize the nanoparticle As a function of a new biological probe, it can be used for the preparation of biological probes, and as a new biological probe, it plays an important role in the sensing and detection of biomolecules in biosensors. In the present invention, 3-aminopropyltriethoxysilane (APTES) and tetraethyl silicate (TEOS) are used as the coating solution, and the surface of rare earth oxide nanoparticles is coated with a layer of polysiloxane through a comprehensive hydrolysis reaction to form Nanoparticles with a core-shell structure. The size of the nanoparticles prepared in the present invention is between 10nm and 100nm, which can be controlled by the ratio of the coating liquid and the precursor synthesis liquid.

Description of drawings

Accompanying drawing 1 is the transmission electron microscope picture of Gd ₂ O ₃ : Tb ³⁺ nanocrystal of the present invention;

Accompanying drawing 2 is the transmission electron micrograph of the core-shell structure nanoparticle Gd ₂ O ₃ : Tb ³⁺ /SiOx of the present invention;

Accompanying drawing 3 is the high-resolution TEM image and energy spectrum analysis of the core-shell structure nanoparticle Gd ₂ O ₃ : Tb ³⁺ /SiOx of the present invention;

Accompanying drawing 4 is the influence of the excitation spectrum before and after coating, the emission spectrum before and after coating and the addition of NaOH on the emission spectrum of nanoparticles Gd2O3: Tb3+/SiOx observed through the fluorescence spectrum;

Accompanying drawing 5 is the fluorescent light intensity of embodiment of the present invention before and after wrapping;

Accompanying drawing 6 is the fluorescent light intensity of the embodiment of the present invention in different sodium hydroxide additions;

Accompanying drawing 7 is the longitudinal relaxation time of the product of the embodiment of the present invention;

Accompanying drawing 8 is the transverse relaxation time of the product of the embodiment of the present invention. the

Detailed ways

Embodiments of the present invention: the preparation method of rare earth nanoparticles with core-shell structure, after getting 1.6950g of gadolinium trichloride and 0.0896g of terbium trichloride to mix, place in a round bottom flask, add 200ml of diethylene glycol, and use a magnetic stirrer to Stir at room temperature for 12 hours to completely dissolve the solvent and mix uniformly; then add 1.44mL of sodium hydroxide solution with a substance concentration of 10mol/L, and add 200ml of diethylene glycol for dilution, and continue stirring for 6 hours to obtain a mixture containing doped Colloidal transparent solution of gadolinium oxide nanoparticles containing Tb ³⁺ ;

Configure coating solution S1: take 53 μL tetraethyl silicate and 83 μL 3-aminopropyltriethoxysilane, mix evenly and put them in a round bottom flask for later use; configure coating solution S2: take 36 μL distilled water, 8 μL triethylamine And 199 μL of diethylene glycol, distilled water, triethylamine and diethylene glycol in a molar ratio of 35:1:37, mix well and place in a round bottom flask for later use; in the dark and at 40°C, calculate by volume percentage, Add 30% of the coating solution S1 into the colloidal transparent solution containing gadolinium oxide nanoparticles doped with Tb ³⁺ , add 30% of the coating solution S2 after 1 hour, and then add the remaining coating solution S1 after 1 hour After another 1 hour, the remaining coating solution S2 was added, and the coating of the polysiloxane layer was completed after stirring for 48 hours to obtain rare earth nanoparticles with a core-shell structure.

The Gd ₂ O ₃ : Tb ³⁺ nanocrystals in the examples were observed under a transmission electron microscope, and the results are shown in FIG. 1 .

The core-shell nanoparticle Gd ₂ O ₃ : Tb ³⁺ /SiOx in the example was observed under a transmission electron microscope, and the results are shown in FIG. 2 .

The high-resolution TEM image and energy spectrum analysis of core-shell structure nanoparticles Gd ₂ O ₃ : Tb ³⁺ /SiOx are shown in Fig. 3 .

The comparison of excitation spectra before and after coating, the comparison of emission spectra before and after coating, and the effect of aOH addition on the emission spectrum of nanoparticles Gd2O3: Tb3+ /SiOx were observed through fluorescence spectra, as shown in Figure 4. the

The relaxation times of the products of the examples are shown in Figures 5 and 6. the

According to the above tests, the average size of the obtained core-shell structure rare earth nanoparticles is 25nm; the core-shell structure nanoparticles are magnetic and luminescent, and can be used in the fields of biosensing and molecular detection. the

The results of photoluminescence spectroscopy show that the cladding layer has little effect on the luminescence performance of the core, and the positions of the peaks in the spectrum do not change. Experimental parameters (such as the amount of NaOH added, etc.) have an impact on the size and luminescent properties of nanoparticles. the

Claims (5)

1. a preparation method of core-shell structure rare earth nanoparticles is characterized in that: adopt polyalcohol as solvent, gadolinium trichloride and terbium trichloride are mixed, make gadolinium trichloride and terbium trichloride dissolve completely, then Sodium hydroxide solution was added to carry out the synthesis reaction to obtain magnetic and luminescent gadolinium oxide nanoparticles doped with Tb ³⁺ ; then the polysiloxane layer was coated on the surface of the gadolinium oxide nanoparticles to obtain rare earth nanoparticles with a core-shell structure. particles. 2. The preparation method of core-shell structure rare earth nanoparticles according to claim 1, characterized in that: the molar ratio of the mixed gadolinium trichloride and terbium trichloride is 95:5; the added sodium hydroxide and The molar ratio of gadolinium trichloride is 3:1. 3. The method for preparing rare earth nanoparticles with core-shell structure according to claim 1, characterized in that: the coating liquid used in the coating polysiloxane layer comprises coating liquid S1 and coating liquid S2; Covering liquid S1 is a mixed solution of tetraethyl silicate and 3-aminopropyltriethoxysilane, the molar ratio of tetraethyl silicate to 3-aminopropyltriethoxysilane is 4:6; Liquid S2 is a mixed solution of distilled water, triethylamine and diethylene glycol. The molar ratio of distilled water, triethylamine and diethylene glycol is 35:1:37; , add 30% coating solution S1 into the colloidal transparent solution containing gadolinium oxide nanoparticles doped with Tb ³⁺ , add 30% coating solution S2 after 1 hour, add the remaining coating solution after 1 hour Solution S1, after another 1 hour, add the remaining coating solution S2, and stir and react for 48 hours to complete the coating of the polysiloxane layer. 4. The method for preparing rare earth nanoparticles with core-shell structure according to claim 1, characterized in that: the time for adding sodium hydroxide solution to carry out the synthesis reaction is more than 6 hours. 5 . The method for preparing rare earth nanoparticles with core-shell structure according to claim 1 , wherein the polyhydric alcohol is diethylene glycol.