CN111646703A - Fluoride/oxyfluoride fluorescent glass ceramic and preparation method and application thereof - Google Patents

Abstract

The invention relates to a fluoride/oxyfluoride nanocrystal composite fluorescent glass ceramic material, a preparation method and application thereof. The fluorescent glass ceramic is composed of a mesoporous silicon-based material and a fluoride/oxyfluoride fluorescent nanocrystal. The invention not only effectively retains the luminescence properties of fluoride/oxyfluoride nanocrystals, but also has great advantages in color displays, sensors, lasers and fiber amplifiers due to its simple preparation process, good thermal stability and long fluorescence life. application potential.

Description

A kind of fluoride/oxyfluoride fluorescent glass ceramic and its preparation method and application

technical field

The invention belongs to the field of fluorescent glass-ceramic materials, and particularly relates to a fluoride/oxyfluoride fluorescent glass-ceramic and a preparation method and application thereof.

Background technique

Fluorescent glass ceramic is a new type of luminescent material, also known as glass-ceramic. It not only has an amorphous matrix, but also coexists with a crystalline phase. Compared with the traditional glass material, the composite material obtained by the heat treatment process not only has the characteristics of glass, such as high hardness, high mechanical strength, good chemical stability, resistance to It has excellent abrasive properties, stable dielectric constant, and has the advantages of high thermal conductivity of ceramic phase crystals and doped luminescent ions. Therefore, it can be used as both a structural material and a functional material, and has gradually been widely used in the fields of energy, chemical industry, biomedicine, automobile, building decoration and so on.

At present, rare earth-doped fluoride/oxyfluoride nanocrystals have been the research hotspot of fluorescent materials due to their low phonon energy, high luminescence efficiency and long fluorescence lifetime. However, their poor thermal stability limits their application in optical applications. applications in the field of devices. Glass materials are ideal matrix materials for nanocrystalline materials due to their high thermal conductivity, good transparency, and high chemical stability. The research idea of preparing nanocrystalline composite fluorescent glass-ceramic composite materials is widely favored by researchers. In the literature (J.Euro.Ceram.Soc., 2019, 39(15):5010-5017), Natalia Pawlik et al. described a preparation method of YF ₃ :Eu ³⁺ composite glass-ceramic with long fluorescence lifetime. However, in the traditional preparation process, the rare earth ion active luminescent centers of the fluoride nanocrystalline composite fluorescent glass ceramics cannot firmly and effectively occupy the fluoride lattice sites, and defects are easily formed, resulting in a decrease in the fluorescence emission intensity and a shortened fluorescence lifetime. , it is difficult to meet the practical application requirements. Therefore, it is very urgent and necessary to develop a fluorescent glass ceramic with high luminous intensity and long fluorescent life.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide a fluoride/oxyfluoride nanocrystal composite fluorescent glass-ceramic material and a preparation method and application thereof. By reducing the sintering temperature, shortening the preparation time, improving the stability of the matrix, etc. By stabilizing rare earth ions on the fluoride/oxyfluoride lattice sites, the fluorescence lifetime and thermal stability of the fluoride/oxyfluoride nanocrystals are extended while retaining the original fluorescent properties of the fluoride/oxyfluoride nanocrystals.

The present invention provides a fluoride/oxyfluoride nanocrystal composite fluorescent glass ceramic material, the material is composed of 95-99% mesoporous silicon-based material and 1-5% fluoride/oxyfluoride fluorescent nanometer in weight percentage. The crystals are mixed and sintered.

The mesoporous silicon-based material is one of SBA series, FDU series, ZSM series and MCM series.

The fluoride fluorescent nanocrystals are LaF ₃ , YF ₃ , Ba ₂ YbF ₇ , NaLuF ₄ or NaGdF ₄ doped with rare earth elements; wherein, the rare earth elements are Eu, La, Er, Yb, Tm or Ho, The element doping ratio (molar percentage) is 1-5%.

The oxyfluoride fluorescent nanocrystals are YOF doped with rare earth elements; wherein, the rare earth elements are Eu, La, Er, Yb, Tm or Ho, and the doping ratio (molar percentage) of rare earth elements is 1-5%.

The average grain size of the fluoride/oxyfluoride fluorescent nanocrystals is 10-100 nm.

The present invention also provides a method for preparing a fluoride/oxyfluoride nanocrystal composite fluorescent glass ceramic material, comprising:

By weight percentage, 95-99% of silicon-based mesoporous powder and 1-5% of fluoride/oxyfluoride fluorescent nanocrystals are uniformly mixed to obtain a composite powder; the composite powder is loaded into a graphite mold, placed in a In the discharge plasma sintering furnace chamber, the composite glass-ceramic is obtained by sintering in a vacuum environment; after cooling, grinding and polishing are performed to obtain the fluoride/oxyfluoride nanocrystal composite fluorescent glass-ceramic material.

The sintering pressure is 50-100 MPa, the sintering time is 5-10 min, the heating rate is 50-150 DEG C/min, the sintering temperature is 950-1050 DEG C, and the holding time is 1-3 minutes.

The invention also provides the application of a fluoride/oxyfluoride nanocrystal composite fluorescent glass ceramic material, which is applied to optical devices, solid-state lasers or biological markers.

beneficial effect

(1) The present invention adopts the spark plasma sintering technology to encapsulate the fluoride/oxyfluoride nanocrystals in the mesoporous silica-based glass. Due to the fast heating rate, low sintering temperature and short holding time, the preparation process is extremely harmful to the composite nanocrystals. It is small and retains the original luminescence properties of fluoride/oxyfluoride nanocrystals to the greatest extent.

(2) The phonon energy of the fluoride/oxyfluoride itself is low, which can well avoid the non-radiative transition in the light-emitting process, and the light conversion efficiency is high. The composite fluorescent glass-ceramic of the present invention not only has the thermal stability of the glass matrix It has the characteristics of good thermal conductivity, high light conversion efficiency and luminous performance of fluoride/oxyfluoride;

(3) The fluorescence lifetime of the composite fluorescent glass-ceramic obtained by the present invention is as long as 6.891 ms, which has application potential in the fields of optical devices and biomarkers.

Description of drawings

1a-b are XRD patterns of the fluoride nanocrystal composite fluorescent glass-ceramic material prepared in Example 1;

2a-b are the fluorescence lifetime diagrams of the fluoride nanocrystal composite fluorescent glass-ceramic material prepared in Example 2;

Figures 3a-d are the fluorescence spectra and physical images of the oxyfluoride nanocrystalline composite fluorescent glass-ceramic material prepared in Example 3.

Detailed ways

The present invention will be further described below in conjunction with specific embodiments. It should be understood that these examples are only used to illustrate the present invention and not to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of the present application.

Example 1

La(NO ₃ ) ₃ ·6H ₂ O and Eu(NO ₃ ) ₃ ·XH ₂ O were accurately weighed in a molar ratio (La:Eu=95:5), dissolved in deionized water at room temperature, and placed at 65 Magnetic stirring in an oil bath at a temperature of 500 rpm; the excess NH ₄ F was dissolved in a small amount of deionized water, the NH ₄ F solution was slowly dropped into the above mixed solution, a white precipitation was observed, and then added The pH value of nitric acid or hydrochloric acid solution was adjusted to 2~3, and the stirring and heating were continued for 90 minutes; the mixed solution was further subjected to hydrothermal treatment, and the mixed solution with precipitation was moved to a 100ml hydrothermal kettle, and the reaction was carried out at 180 °C for 18 hours. , take out the hydrothermal kettle and naturally cool to room temperature, pour the supernatant, wash and centrifuge the precipitate three times with deionized water and absolute ethanol, respectively, and place the obtained white precipitate in a blast drying oven at 60°C. Under drying for 24h, LaF ₃ :Eu ³⁺ nanocrystals were obtained.

The mesoporous FDU-12 silicon-based powder and LaF ₃ :Eu ³⁺ luminescent nanocrystalline powder were used as starting materials. The raw materials were uniformly ground and mixed according to different weight ratios (LaF ₃ :Eu ³⁺ luminescent nanocrystalline powder: 1wt%, 2wt%, 3wt%, 4wt%, 5wt%), and then moved into a graphite mold with an inner diameter of 10mm. Through spark plasma sintering, the mixed powder was sintered under a uniaxial pressure of 50 MPa for about 10 min according to specific sintering parameters. The detailed sintering parameters are as follows: after heating at 600 °C for 3 min, the mixed powder is sintered at high temperature with a heating rate of 120 °C/min. At a sintering temperature of 950°C, the holding time is about 1min, and a composite fluorescent glass ceramic sample is obtained. All samples were surface polished twice to a thickness of 1 mm. Its crystal form was tested by XRD, and the results are shown in Figure 1a-b. The morphologies of the LaF ₃ :Eu ³⁺ nanocrystals were characterized by SEM and TEM. The size of the LaF 3 :Eu 3+ nanocrystals was about 50 nm. It was proved that the nanocrystals were uniformly dispersed in the glass matrix without serious interfacial reaction. Using a fluorescence spectrometer to test its excitation emission spectrum, it can be seen that it has red light emission at 590 nm and 612 nm under the excitation of 396 nm. The experimental results show that the fluoride nanocrystals are successfully compounded inside the silicon-based glass, and the optical properties are effectively protected.

Example 2

Y(NO ₃ ) ₃ ·6H ₂ O and Eu(NO ₃ ) ₃ ·XH ₂ O were accurately weighed in a molar ratio (Y:Eu=95:5), dissolved in deionized water at room temperature, and placed at 65°C Magnetic stirring in an oil bath of 500 rpm; excess NH ₄ F was dissolved in a small amount of deionized water, and the NH ₄ F solution was slowly dropped into the above mixed solution, white precipitation was observed, and then a certain amount of Amount of nitric acid or hydrochloric acid solution to adjust the pH value to 2 ~ 3, continue to stir and heat for 90min; further hydrothermally treat the mixed solution, move the mixed solution with precipitation to a 100ml hydrothermal kettle, and react at 180 ° C for 18h, the reaction After the end, the hydrothermal kettle was taken out and cooled to room temperature naturally, the supernatant was poured out, the precipitate was washed and centrifuged three times with deionized water and absolute ethanol, respectively, and the obtained white precipitate was placed in a blast drying oven at 60 °C. Dry at ℃ for 24h to obtain YF ₃ :Eu ³⁺ nanocrystals.

The mesoporous SBA-15 silicon-based powder and YF ₃ :Eu ³⁺ luminescent nanocrystalline powder were used as starting materials. The raw materials were uniformly ground and mixed in different weight ratios (YF ₃ :Eu ³⁺ luminescent nanocrystalline powder: 1wt%, 2wt%, 3wt%, 4wt%, 5wt%), and then moved into a graphite mold with an inner diameter of 10mm. Through spark plasma sintering, the mixed powder was sintered under a uniaxial pressure of 80 MPa for about 10 min according to specific sintering parameters. The detailed sintering parameters are as follows: after heating at 600 °C for 3 min, the mixed powder is sintered at high temperature with a heating rate of 120 °C/min. At the sintering temperature of 1000 °C, the holding time is about 1 min to obtain the composite glass-ceramic sample. All samples were surface polished twice to a thickness of 1 mm. Through XRD testing its crystal form, it can be seen that there are YF ₃ :Eu ³⁺ nanocrystal diffraction peaks in the composite glass-ceramic. The morphology of YF ₃ :Eu ³⁺ nanocrystals was 150 nm in size and uniformly dispersed by SEM and TEM. The fluorescence lifetime was tested by a fluorescence spectrometer transient spectrometer, as shown in Fig. 2a-b. Using a fluorescence spectrometer to test its excitation emission spectrum, it can be seen that the nanocrystal and its glass-ceramic composite have the same 592nm red light emission under the excitation of 393nm.

Example 3

The YF ₃ :Eu ³⁺ nanocrystals dried after centrifugation in Example 2 were fully ground in a mortar, and then the powder was placed in a muffle furnace and heated to 300° C. and 400° C. at a heating rate of 2° C./min. , 500°C, 600°C, 700°C, 800°C, and 900°C, and naturally cooled to room temperature after holding for three hours to obtain YOF:Eu ³⁺ nanocrystals.

MCM-41 mesoporous silicon-based powder and YOF:Eu ³⁺ luminescent nanocrystalline powder were used as starting materials. The raw materials were uniformly ground and mixed according to different weight ratios (YOF:Eu ³⁺ luminescent nanocrystalline powder: 1wt%, 2wt%, 3wt%, 4wt%, 5wt%), and then moved into a graphite mold with an inner diameter of 10mm. Through spark plasma sintering, the mixed powder was sintered under a uniaxial pressure of 100 MPa for about 10 min according to specific sintering parameters. The detailed sintering parameters are as follows: after heating at 600 °C for 3 min, the mixed powder is sintered at high temperature with a heating rate of 120 °C/min. At the sintering temperature of 1050 °C, the holding time is about 2 minutes to obtain the composite glass-ceramic sample. All samples were surface polished twice to a thickness of 1 mm. It can be seen from the XRD test of its crystal form that there are YOF:Eu ³⁺ nanocrystal diffraction peaks and no other impurity diffraction peaks in the composite glass-ceramic. The morphologies of YOF:Eu ³⁺ nanocrystals were uniformly dispersed by SEM and TEM, and there was no obvious interfacial reaction with silica. The excitation emission spectrum was tested by a fluorescence spectrometer, and the results are shown in Figure 3. Figure 3a-b are the excitation emission spectra of the YOF:Eu ³⁺ glass-ceramic composite material and the YOF:Eu ³⁺ nanocrystalline powder, respectively. There is the same optimal excitation wavelength of 393 nm, and the main emission peak position has not changed significantly except for the emission peak broadening caused by the internal structural defects of the glass ceramics. Figure 3c shows the emission spectra of glass-ceramics with different YOF:Eu ³⁺ contents, all of which show characteristic peaks of Eu ³⁺ ions, and the luminescence intensity increases with the increase of nanocrystal content. Figure 3d is the actual image of the YOF:Eu ³⁺ glass-ceramic.

Claims (8)

1. A fluoride/oxyfluoride nanocrystal composite fluorescent glass-ceramic material, characterized in that: the material is composed of 95-99% mesoporous silicon-based material and 1-5% fluoride/oxyfluoride by weight percentage The fluorescent nanocrystals are mixed and sintered. 2 . The material according to claim 1 , wherein the mesoporous silicon-based material is one of SBA series, FDU series, ZSM series and MCM series. 3 . 3 . The material according to claim 1 , wherein the fluoride fluorescent nanocrystals are LaF ₃ , YF ₃ , Ba ₂ YbF ₇ , NaLuF ₄ or NaGdF ₄ doped with rare earth elements; wherein, the rare earth element The elements are Eu, La, Er, Yb, Tm or Ho, and the doping ratio of rare earth elements is 1-5%. 4 . The material according to claim 1 , wherein the oxyfluoride fluorescent nanocrystals are YOF doped with rare earth elements; wherein, the rare earth elements are Eu, La, Er, Yb, Tm or Ho, 5 . The doping ratio of rare earth elements is 1-5%. 5 . The material according to claim 1 , wherein the average grain size of the fluoride/oxyfluoride fluorescent nanocrystals is 10-100 nm. 6 . 6. A preparation method of a fluoride/oxyfluoride nanocrystal composite fluorescent glass-ceramic material, comprising: By weight percentage, 95-99% of silicon-based mesoporous powder and 1-5% of fluoride/oxyfluoride fluorescent nanocrystals are uniformly mixed to obtain a composite powder; the composite powder is loaded into a graphite mold, placed in a In the discharge plasma sintering furnace chamber, the composite glass-ceramic is obtained by sintering in a vacuum environment; after cooling, grinding and polishing are performed to obtain the fluoride/oxyfluoride nanocrystal composite fluorescent glass-ceramic material. 7 . The preparation method according to claim 6 , wherein the sintering pressure is 50-100 MPa, the sintering time is 5-10 min, the heating rate is 50-150° C./min, and the sintering temperature is 950-1050° C. 8 . , the holding time is 1 ~ 3min. 8. An application of the fluoride/oxyfluoride nanocrystal composite fluorescent glass-ceramic material according to claim 1, characterized in that: it is applied to optical devices, solid-state lasers or biological markers.

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