CN112978793B

CN112978793B - TiO22W nano-particles, preparation method and application thereof

Info

Publication number: CN112978793B
Application number: CN202110305811.2A
Authority: CN
Inventors: 高惠平; 毛艳丽; 刘越峰; 金苏月
Original assignee: Henan University
Current assignee: Henan University
Priority date: 2021-03-23
Filing date: 2021-03-23
Publication date: 2022-03-08
Anticipated expiration: 2041-03-23
Also published as: CN112978793A

Abstract

The invention discloses a TiO compound₂W nano-particles, a preparation method and application thereof, belonging to the technical field of fluorescent materials. The TiO2: W nano-particles are obtained by the following processes: (1) mixing Ti (OEt)₄、WCl₆Mixing octadecene, oleylamine, oleic acid, octadecanol and ammonium fluoride to obtain a mixture; (2) heating the mixture to 55-65 ℃ in a nitrogen atmosphere, vacuumizing, and heating to 100-120 ℃ in a vacuum state for 10-30 min; (3) and then heating to 270-290 ℃ in a nitrogen atmosphere, preserving the heat for 0.5-1.5 h, cooling the system to 55-65 ℃ after the reaction is finished, adding acetone for precipitation, centrifuging, and cleaning the solid to obtain the catalyst. TiO prepared by the invention₂The luminescence property of the up-conversion nano particles is effectively improved by compounding W and the up-conversion nano particles, and the maximum luminescence property reaches 17 times.

Description

TiO22W nano-particles, preparation method and application thereof

Technical Field

The invention belongs to the field of fluorescent materials, and particularly relates to a TiO-based fluorescent material₂W nanocrystalline up-conversion luminescent material and a preparation method thereof.

Background

Upconversion luminescence refers to the optical process of converting two or more low energy photons into one high energy photon. The rare earth up-conversion luminescent material has the advantages of rich spectrum, narrow emission spectrum, long luminescent life, good optical stability and the like, and has application prospects in the fields of medical imaging, biosensing, three-dimensional display, photodynamic therapy, solar photocatalysis, solar cells and the like. However, in the rare earth up-conversion luminescent material, the characteristics of small absorption cross section of rare earth ions, narrow excitation band and rich intermediate state energy level make the up-conversion luminescent efficiency low. To date, various approaches to enhance rare earth up-conversion luminescence have been tried, but some distance has been left from practical use. Obtaining efficient up-conversion luminescence remains a major challenge for the development and utilization of rare earth up-conversion luminescent materials. In recent years, the manipulation of the localized electromagnetic field of the luminescence process by using the Localized Surface Plasmon Resonance (LSPR) effect of noble metal or semiconductor nanocrystals is one of the most effective methods to enhance up-converted luminescence (ACS Appl. mater. Interface, 2021, 13:2674; Nano Energy, 2019, 61: 211; Nanoscale 2018, 10:6270; Ceram int, 2019, 45: 21557). Compared with precious metal nanocrystals, the semiconductor nanocrystals have the advantages of low cost, easy regulation and control of the LSPR effect and the like, and in order to further improve the luminous intensity and efficiency of the rare earth up-conversion luminescent material, the urgent need is to find a semiconductor nanocrystal material with an obvious LSPR effect and effectively couple the semiconductor nanocrystal material with the up-conversion luminescent material.

Disclosure of Invention

The invention aims to provide TiO₂W nanoparticles, a preparation method and application thereof. The invention firstly prepares high-quality tungsten-doped titanium dioxide (TiO) with uniform size, good dispersibility and obvious LSPR effect₂W) nanoparticles, TiO prepared by the invention₂The W nano-particles are used as the center of the LSPR effect and applied to the rare earth doping up-conversion luminescent nano-material, the LSPR effect is utilized to enhance the light absorption of rare earth ions in a near infrared band, and the luminescence of the rare earth doping up-conversion luminescent material is improved.

The technical problem to be solved by the invention is to utilize TiO₂The LSPR effect of W nanoparticles can raise the luminous intensity of RE doped up-converting luminescent material by constituting TiO₂The composite structure of W and up-conversion nano particles influences the up-conversion luminescence process by means of the LSPR effect, and effectively improves the up-conversion luminescence of the rare earth doped material.

The invention provides a method for preparing a catalyst based on TiO₂The preparation method of the composite material with the W nanocrystalline LSPR effect for enhancing the up-conversion luminescence comprises the following two types: (1) the layered structure comprises an upper layer and a lower layer, wherein the lower layer is silicon dioxide (SiO)₂) Coated TiO₂W nanocrystalline, the upper layer is rare earth doped up-conversion nano material; (2) core-shell structure of TiO₂W nanocrystalline is adsorbed on the surface of rare earth doped up-conversion nano particles.

Based on the purpose, the invention is realized by the following technical scheme:

a TiO 2W nanoparticle obtained by the following process:

(1) mixing Ti (OEt)₄、WCl₆Mixing octadecene, oleylamine, oleic acid, octadecanol and ammonium fluoride to obtain a mixture;

(2) heating the mixture to 55-65 ℃ in a nitrogen atmosphere, vacuumizing, and heating to 100-120 ℃ in a vacuum state for 10-30 min;

(3) heating to 270-290 ℃ in a nitrogen atmosphere, preserving heat for 0.5-1.5 h, cooling the system to 55-65 ℃ after the reaction is finished, adding acetone for precipitation, centrifuging, cleaning the solid, and dispersing the obtained solid in n-hexane to obtain TiO₂W n-hexane solution.

Preferably, each 1 mmol of Ti (OEt)₄0.05-0.2 mmol WCl needs to be added₆6-10 mL of octadecene, 0.3-0.6 mL of oleylamine, 0.3-0.6 mL of oleic acid, 6-10 mmol of octadecanol and 0.2-2.6 mmol of ammonium fluoride.

Use of the above TiO₂TiO made of W nano-particles₂:W @SiO₂The preparation process of the nano-particles is as follows: dispersing 0.5-0.9 mL of nonyl phenol polyether-5 in n-hexane, and then adding TiO₂Adding strong ammonia water into W normal hexane solution, adding tetraethyl silicate, stirring for 20-30 h at normal temperature, adding acetone for precipitation after the reaction is finished, centrifuging, cleaning solids, and dispersing obtained transparent colloid in ethanol.

Preferably, the TiO is₂The concentration of W n-hexane solution is 0.04 mmol/mL, the adding amount is 0.5 mL, the adding amount of concentrated ammonia water is 0.08mL, and the using amount of tetraethyl silicate is 100-160 muL.

The above TiO compound₂The application of the W nano-particles in enhancing the luminous intensity of the rare earth doped up-conversion luminescent nano-material comprises the following specific processes:

(1) will 10mLNaYF₄:Yb³⁺,Re³⁺(Re = Er, Tm and Ho) concentration of 0.025-0.035 mmol/mL NaYF₄:Yb³⁺,Re³⁺@NaGdF₄Nano materialThe cyclohexane solution, 5-10 mL of DMF, and 100-150 mg of (CH)₃)₃OBF₄Mixing, stirring for 10-20 min, adding toluene for precipitation, centrifuging, and dispersing the precipitate in water

Forming a positively charged solution a in DMF;

(2) adding 5mL of 0.04 mmol/mL TiO₂W nanoparticle solution, 5-10 mL DMF, 100-120 mg (CH)₃)₃OBF₄Mixing, stirring for 10-20 min, adding toluene for precipitation, centrifuging, and dispersing the precipitate in 10mL of DMF;

(3) adding 80-100 mg of polyacrylic acid into the product obtained in the step (2), stirring for 8-12 h, adding toluene after full reaction for precipitation, centrifuging, and re-dispersing the nanoparticles in ultrapure water to obtain a solution B with negative electricity;

(4) and (3) mixing the solution B obtained in the step (3) with the solution A obtained in the step (1), continuously stirring the obtained mixture for 1.5-2.5 h, adding toluene to precipitate a composite structure, centrifuging, and drying the obtained precipitate to obtain a product.

Preferably, NaYF₄:Yb³⁺,Re³⁺(Re = Er, Tm and Ho) with TiO₂The molar ratio of W is 30-40: 1.

The above TiO compound₂:W @SiO₂The application of the nano-particles in enhancing the luminous intensity of the rare earth doped up-conversion luminescent nano-material.

(1) Preparing normal hexane solution of rare earth doped up-conversion luminescent nano material with same molar concentration and TiO₂:W @SiO₂An ethanol solution of nanoparticle particles;

(2) rare earth doped n-hexane solution of up-conversion luminescent nano material and TiO₂:W @SiO₂Sequentially spin-coating an appropriate amount of ethanol solution of the nano-particle particles on a clean glass sheet, and irradiating the surface of the film for 5-10 min by using an ultraviolet light cleaning machine after each spin-coating is finished;

(3) and (4) annealing at 85-95 ℃ to obtain the product.

Preferably, the rare earth doped up-conversion luminescent nano material is NaYF₄: Yb³⁺, Re³⁺(Re = Er, Tm and Ho).

60-80 μ L of NaYF with a concentration of 0.01-0.03 mmol/mL₄:Yb³⁺,Re³⁺The solution is coated on the glass in a spinning way, the rotating speed is 2000-4000 revolutions per minute, and the time is 30-50 s. And irradiating the film for 8 min by using an ultraviolet light cleaning machine after film coating. Then, spin-coating 60-80 μ L TiO with concentration of 0.01-0.02 mmol/mL for 30-50 s at 2000-4000 rpm₂:W @SiO₂And (3) coating the nanocrystalline solution, and irradiating the film for 5-10 min by using an ultraviolet light cleaning machine. Finally, the resulting layered structure was annealed at 90 ℃ for 10 min.

Advantages of the invention

Compared with the prior art, the invention has the following advantages:

(1) the invention adopts ammonium fluoride to assist in synthesizing TiO₂W nanocrystalline, TiO with different sizes and crystal forms can be obtained by changing the dosage of ammonium fluoride₂W nanocrystalline, LSPR characteristic of the material changes obviously with the change of the dosage of ammonium fluoride, and the synthesis efficiency is high.

(2) The LSPR effect utilized by the invention is from semiconductor nanocrystalline TiO₂W has low cost and simple preparation method compared with the traditional LSPR material.

(3) TiO-based material prepared by the invention₂The composite of W and the up-conversion nano particles effectively improves the luminescence performance of the up-conversion nano particles compared with the pure up-conversion nano particles, and the highest enhancement factor reaches 17 times.

(4) The LSPR effect utilized by the invention is derived from TiO₂W nanocrystals, TiO compared to other LSPR materials₂Has better biological application and photoelectric application prospect, and the TiO-based material prepared by the invention₂W nanocrystalline up-conversion composite materials are expected to be applied to anti-counterfeiting materials, photocatalysis, biotherapy, perovskite solar cells and the like in the future.

Drawings

FIG. 1 is the TiO synthesized in example 1₂Transmission Electron Micrograph (TEM) of W nanocrystals.

FIG. 2 isTiO obtained in example 1₂:W@SiO₂TEM image and TiO of₂:W@SiO₂/ NaYF₄: Yb³⁺,Er³⁺Scanning electron micrographs of the layered film; a is TiO in example 1₂:W@SiO₂TEM image of (b) TiO in example 1₂:W@SiO₂/ NaYF₄: Yb³⁺,Er³⁺Scanning Electron Micrographs (SEM) of the layered film.

FIG. 3 shows NaYF in example 1₄: Yb³⁺,Er³⁺Film a and with TiO₂:W@SiO₂TiO of the layer₂:W@SiO₂/ NaYF₄: Yb³⁺,Er³⁺Luminescence of film b with a 980 nm laser, and up-conversion luminescence spectra of film a and film b.

FIG. 4 is TiO synthesized in example 2₂Transmission Electron Micrograph (TEM) of W nanocrystals.

FIG. 5 shows NaYF in example 2₄:Yb³⁺,Tm³⁺@NaGdF₄:Yb³⁺@TiO₂TEM image of W core-shell composite structure.

FIG. 6 shows NaYF in different ratios in example 2₄:Yb³⁺,Tm³⁺@NaGdF₄:Yb³⁺With TiO₂Upconversion fluorescence spectra of W composite structures.

FIG. 7 shows TiO synthesized in example 3₂Transmission Electron Micrograph (TEM) of W nanocrystals.

Detailed Description

The following examples are presented to illustrate the present invention and to enable those skilled in the art to better understand and practice the invention. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended.

Example 1:

based on TiO₂The method for enhancing the up-conversion luminescence by the W plasma resonance effect comprises the following steps:

(1) 1 mmol of Ti (OEt)₄、 0.15 mmol WCl₆8mL ODE, 0.5 mL OLA, 0.5 mL OA, 10 mmol ODAL, and 0.8 mmol NH₄F was mixed in 50mL of threeIn a neck flask.

(2) The mixture in the step (1) is heated to 60 ℃ under nitrogen, vacuum pumping is started, and the mixture is heated to 110 ℃ under the vacuum state and is kept for 20 min.

(3) And (3) quickly heating the reaction mixture in the step (2) to 280 ℃ in a nitrogen atmosphere, and preserving the temperature for 1 h.

(4) And (3) after the reaction in the step (3) is finished, cooling to 60 ℃, adding acetone, stirring for 10min, centrifuging at 8000 rpm for 3 min, dispersing into n-hexane, and cleaning for three times by using the n-hexane and acetone in a volume ratio of 1: 1. Finally dispersing the precipitate in 25 mL of n-hexane to obtain TiO with the concentration of 0.04 mmol/mL₂W solution.

FIG. 1 is the TiO synthesized in example 1₂Transmission Electron Micrograph (TEM) of W nanocrystals. The lattice spacing of 0.35 marked in graph b is ascribed to anatase TiO₂The (101) crystal plane of (a). Synthetic TiO₂The W nano-crystal has good dispersibility, uniform size and about the same size.

(5) Dispersing 0.7 mL of CO-520 in 10mL of n-hexane, adding 0.5 mL of the solution obtained in step (4), 0.08mL of concentrated ammonia water, and sonicating for 20 min.

(6) And (3) adding 120 mu L of tetraethyl silicate into the solution in the step (5), and vigorously stirring at normal temperature for 24 hours.

(7) After the reaction in the step (6) is finished, adding acetone, stirring for 10min, centrifuging at 8000 rpm for 3 min, mixing water and alcohol 1:1 amount of washing twice. Finally dispersing the precipitate in 1mL of ethanol to obtain TiO with the concentration of 0.02 mmol/mL₂:W@SiO₂And (3) solution.

FIG. 2a is the TiO of example 1₂W nanocrystal coated SiO₂Layered TiO₂:W@SiO₂In the TEM image, it can be seen that no agglomeration and SiO occurred after the coating₂The layer thickness is uniform.

(8) Adding 0.78 mmol YCl₃、0.2 mmol YbCl₃、0.02 mmol ErCl₃15 mL ODE and 7.5mL OA are added into a three-necked bottle, nitrogen is introduced, mixed and stirred for 10min, the mixture is gradually heated to 150 ℃ to form a golden transparent oleate precursor, and then the temperature is reduced to the room temperature.

(9) In step (b)To the solution of step (8) were added 0.1 g of NaOH and 0.148 g of NH₄And F, 10mL of methanol solution, stirring for 30min, heating to 80 ℃, and keeping for 10 min.

(10) And (4) after the step (9) is finished, heating to 290 ℃, preserving the heat for 1 h in the nitrogen atmosphere, and then cooling to room temperature.

(11) Precipitating the product obtained in the step (10) by using alcohol, centrifuging for 3 min at 8000 rpm, and washing for three times by using alcohol and cyclohexane in a volume ratio of 1: 1. Dispersing the final product in 50mL of cyclohexane to obtain NaYF with the concentration of 0.02 mmol/mL₄:Yb³⁺，Er³⁺And (3) solution.

(12) Taking 70 mu L of the solution obtained in the step (11), rotating at the rotating speed of 3000 rpm for 30 s, spin-coating the solution on a clean glass sheet, and irradiating the surface of the film for 8 min by using an ultraviolet light cleaning machine to obtain NaYF₄: Yb³⁺,Er³⁺And (3) taking 70 mu L of the solution obtained in the step (7), spinning the solution on the film a for 30 s at the rotating speed of 3000 rpm, and irradiating the surface of the film for 8 min by using an ultraviolet light cleaner to obtain a film b.

(13) Finally, the resulting layered structure was annealed at 90 ℃ for 10 min.

FIG. 2b is the TiO of example 1₂:W@SiO₂/ NaYF₄: Yb³⁺,Er³⁺Scanning Electron Micrographs (SEM) of the films. The prepared film is flat and the particles are uniformly distributed. FIGS. 3a and 3b are NaYF, respectively₄: Yb³⁺,Er³⁺Film a and with TiO₂:W@SiO₂TiO of the layer₂:W@SiO₂/ NaYF₄: Yb³⁺,Er³⁺Film b emitted light with a 980 nm laser, and FIG. c shows the upconversion emission spectra of film a and film b. Description of TiO₂:W@SiO₂The use of layers enhances the NaYF₄: Yb³⁺,Er³⁺The up-conversion of the film emits light, and the enhancement factor reaches 17 times.

Example 2:

(1) 1 mmol of Ti (OEt)₄、 0.10 mmol WCl₆8mL ODE, 0.5 mL OLA, 0.5 mL OA, 10 mmol ODAL, and 2 mmol NH₄F was mixed in a 50mL three-necked flask.

FIG. 4 is TiO synthesized in example 2₂Transmission Electron Micrograph (TEM) of W nanocrystals. The lattice spacing of 0.35 marked in graph b is ascribed to anatase TiO₂The (101) crystal plane of (a). Synthetic TiO₂The W nano-crystal has good dispersibility and uniform size, and the average size is 8 nm.

(5) Adding 0.78 mmol YCl₃、0.2 mmol YbCl₃、0.02 mmol TmCl₃15 mL ODE and 7.5mL OA are added into a three-necked bottle, nitrogen is introduced, mixed and stirred for 10min, the mixture is gradually heated to 150 ℃ to form a golden transparent oleate precursor, and then the temperature is reduced to the room temperature.

(6) 0.1 g of NaOH and 0.148 g of NH were added to the solution of step (5)₄And F, 10mL of methanol solution, stirring for 30min, heating to 80 ℃, and keeping for 10 min.

(7) And (6) after the step (6) is finished, heating to 290 ℃, keeping the temperature for 1 h in the nitrogen atmosphere, and then cooling to room temperature.

(8) And (3) precipitating and centrifuging the product obtained in the step (7), and washing for three times by using alcohol and cyclohexane in a volume ratio of 1: 1. Dispersing the final product in 6 mL of cyclohexane to obtain NaYF₄:Yb³⁺,Tm³⁺A solution with a concentration of 0.167 mmol/mL.

(9) 1 mmol of GdCl₃15 mL ODE and 7.5mL OA were added to a three-necked flask, mixed and stirred for 10min with nitrogen, graduallyHeating to 150 deg.C to form transparent oleate precursor, and cooling to room temperature. Adding the NaYF obtained in the step (8)₄:Yb³⁺,Tm³⁺The solution was 2mL and stirred vigorously for 20 min.

(10) Repeating steps (6) to (7) after step (9) is completed. The resulting product was precipitated, centrifuged, and washed three times with ethanol and cyclohexane in a 1:1 (by volume) ratio. Final product NaYF₄:Yb³⁺,Tm³⁺@NaGdF₄The nanocrystals were dispersed in 10mL of cyclohexane.

(11) Mixing 10mL of NaYF obtained in step (10)₄:Yb³⁺,Tm³⁺@NaGdF₄Nanocrystalline solution with 8mL of DMF, 120 mg of (CH)₃)₃OBF₄And (4) mixing. Stirring vigorously for 15 min, adding 25 mL of toluene for precipitation, centrifuging, and re-dispersing the precipitate in 8mL of DMF to obtain positively charged solution A, i.e. NaYF₄:Yb³⁺,Tm³⁺NaYF with concentration of 0.042 mmol/mL₄:Yb³⁺,Tm³⁺@NaGdF₄And (4) a nanocrystalline solution.

(12) 5mL of TiO obtained in the step (4)₂W nanocrystal with 8mL DMF, 110 mg (CH)₃)₃OBF₄And (4) mixing. After vigorous stirring for 15 min, 25 mL of toluene were added for precipitation, after centrifugation, the precipitate was redispersed in 10mL of DMF.

(13) The polyacrylic acid (PAA) having a molecular weight of 2000, obtained in step (12), was added in an amount of 100 mg and stirred overnight. Adding 25 mL of toluene after full reaction, precipitating, centrifuging, and re-dispersing the nanoparticles in 10mL of ultrapure water to obtain a negatively charged solution B, namely TiO with the concentration of 0.02 mmol/mL₂W nanocrystalline solution.

(14) 0.1mL of the solution B obtained in step (13) was mixed with 1.43 mL, 1.67 mL and 1.89 mL of the solution A obtained in step (11), respectively, and the resulting mixture was stirred for 2 hours. The composite was precipitated by adding 25 mL of toluene and centrifuged. The resulting clear precipitate was dried at 60 ℃ for 5 h. Obtaining NaYF in the product₄:Yb³⁺,Tm³⁺With TiO₂The molar ratio of W is respectively as follows: 30:1, 35:1 and 40:1。

FIG. 5 shows NaYF in example 2₄:Yb³⁺，Tm³⁺@NaGdF₄Nanocrystalline and TiO₂TEM image of core-shell structure formed by W nanocrystals, TiO can be seen₂W nanocrystals adsorbed on NaYF₄:Yb³⁺，Tm³⁺@NaGdF₄Above the inert shell of the nanocrystal, a significant fluoride NaGdF is observed in FIG. 5b₄And oxide TiO₂The lattice fringes of (2). FIG. 6 is a NaYF₄:Yb³⁺，Tm³⁺@NaGdF₄Nanocrystalline and TiO₂When the ratio of the W nanocrystalline to the W nanocrystalline is 35:1, the fluorescence is enhanced most obviously, and the enhancement factor reaches 12 times.

Example 3

(1) 1 mmol of Ti (OEt)₄、 0.10 mmol WCl₆8mL ODE, 0.5 mL OLA, 0.5 mL OA, 10 mmol ODAL, and 2.6 mmol NH₄F was mixed in a 50mL three-necked flask.

FIG. 7 is TiO synthesized in example 1₂Transmission Electron Micrograph (TEM) of W nanocrystals. The lattice spacing of 0.35 marked in FIG. 7b is ascribed to anatase TiO₂The (101) crystal plane of (a). Synthetic TiO₂The W nano-crystal has good dispersibility, uniform size and about 8.5 nm.

(7) After the reaction in the step (6) is finished, adding acetone, stirring for 10min, centrifuging at 8000 rpm for 3 min, mixing water and alcohol 1:1 amount of washing twice. Finally dispersing the precipitate in 1mL of ethanol to obtain TiO with the concentration of 0.02 mmol/mL₂:W@SiO₂And (3) solution. The resulting TiO₂:W@SiO₂The solution can be compounded with rare earth doped up-conversion nanoparticles to improve up-conversion luminescence.

While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention.

Claims

1. TiO2₂The application of the W nano-particles in enhancing the luminous intensity of the rare earth doped up-conversion luminescent nano-material is characterized by comprising the following specific steps:

(1) 10mL NaYF₄:Yb³⁺,Re³⁺@NaGdF₄Cyclohexane solution of nano material, 5-10 mL of DMF, and 100-150 mg of (CH)₃)₃OBF₄Mixing, stirring for 10-20 min, adding toluene for precipitation, centrifuging, and dispersing the precipitate in DMF to form positively charged solution A, wherein NaYF is contained in the positively charged solution A₄:Yb³⁺,Re³⁺@NaGdF₄The concentration of the nano material is 0.042 mmol/mL, wherein Re = Er, Tm or Ho;

(4) mixing the solution B obtained in the step (3) with the solution A obtained in the step (1), continuously stirring the obtained mixture for 1.5-2.5 h, adding toluene to precipitate a composite structure, centrifuging, and drying the obtained precipitate to obtain a product;

the TiO is₂W nanoparticles obtained by the following process:

(a) mixing Ti (OEt)₄、WCl₆Mixing octadecene, oleylamine, oleic acid, octadecanol and ammonium fluoride to obtain a mixture;

(b) heating the mixture to 55-65 ℃ in a nitrogen atmosphere, vacuumizing, and heating to 100-120 ℃ in a vacuum state for 10-30 min;

(c) heating to 270-290 ℃ in a nitrogen atmosphere, preserving heat for 0.5-1.5 h, cooling the system to 55-65 ℃ after the reaction is finished, adding acetone for precipitation, centrifuging, cleaning the solid, and dispersing the obtained solid in n-hexane to obtain TiO₂W n-hexane solution.

2. Use according to claim 1, characterized in that every 1 mmol of Ti (OEt)₄0.05-0.2 mmol WCl needs to be added₆6-10 mL of octadecene, 0.3-0.6 mL of oleylamine, 0.3-0.6 mL of oleic acid, 6-10 mmol of octadecanol and 0.2-2.6 mmol of ammonium fluoride.

3. The use of claim 1, wherein the NaYF is₄:Yb³⁺,Re³⁺@NaGdF₄With TiO₂The molar ratio of W is 30-40: 1.

4. TiO2₂:W @SiO₂The application of the nano-particles in enhancing the luminous intensity of the rare earth doped up-conversion luminescent nano-material is characterized in that the process is as follows:

(1) preparing normal hexane of rare earth doped up-conversion luminescent nano material with same molar concentrationSolution and TiO₂:W @SiO₂An ethanol solution of nanoparticles;

(2) rare earth doped n-hexane solution of up-conversion luminescent nano material and TiO₂:W @SiO₂Sequentially spin-coating an appropriate amount of ethanol solution of the nano particles on a clean glass sheet, and irradiating the surface of the film for 5-10 min by using an ultraviolet light cleaning machine after each spin-coating is finished; the rare earth doped up-conversion luminescent nano material is NaYF₄: Yb³⁺, Re³⁺Wherein Re = Er, Tm or Ho;

(3) annealing at 85-95 ℃ to obtain the product;

the TiO is₂:W @SiO₂The nanoparticles are obtained by the following process:

(c) heating to 270-290 ℃ in a nitrogen atmosphere, preserving heat for 0.5-1.5 h, cooling the system to 55-65 ℃ after the reaction is finished, adding acetone for precipitation, centrifuging, cleaning the solid, and dispersing the obtained solid in n-hexane to obtain TiO₂W n-hexane solution;

(d) dispersing 0.5-0.9 mL of nonyl phenol polyether-5 in n-hexane, and then adding TiO₂Adding strong ammonia water into W normal hexane solution, adding tetraethyl silicate, stirring for 20-30 h at normal temperature, adding acetone for precipitation after the reaction is finished, centrifuging, cleaning solids, and dispersing obtained transparent colloid in ethanol.

5. The use according to claim 4, wherein each 1 mmol of Ti (OEt)₄0.05-0.2 mmol WCl needs to be added₆6-10 mL of octadecene, 0.3-0.6 mL of oleylamine, 0.3-0.6 mL of oleic acid, 6-10 mmol of octadecanol and 0.2-2.6 mmol of ammonium fluoride.

6. Use according to claim 4, whichCharacterized in that the TiO is₂The concentration of W n-hexane solution is 0.04 mmol/mL, the adding amount is 0.5 mL, the adding amount of concentrated ammonia water is 0.08mL, and the using amount of tetraethyl silicate is 100-160 muL.