CN105602564B - A kind of enhanced rare-earth oxide sulfate up-conversion luminescent material of Zn and preparation method - Google Patents

Abstract

The invention provides a Zn-enhanced rare-earth sulfur oxide up-conversion luminescent material and a preparation method. The chemical formula of the material is (Ln _1-x-y-z Yb _x RE _y Zn _z ) ₂ O ₂ S, wherein 0.04≤ x≤0.2, 0.005≤y≤0.02, 0.005≤z≤0.02; Ln is one of La, Y or Gd, and RE is one of Er, Ho, Tm, Pr, Eu or Tb. The luminous intensity of the material is greatly enhanced by 50% to 120%. The preparation method of the material adopts the method of back-dropping the precipitant to obtain the rare earth oxide raw material, and then adopts the gas vulcanization method. The reaction conditions are simple and easy to control. This method can well maintain the morphology and particle size of the rare earth oxide. The rare earth sulfur oxide up-conversion luminescent materials prepared by the method are mostly spherical, with uniform particle size and narrow particle distribution range, D ₉₀ =0.2-0.5 μm.

Description

A Zn-enhanced rare-earth sulfur oxide up-conversion luminescent material and its preparation method

technical field

The invention relates to the field of fine chemical industry, in particular to a Zn-enhanced rare earth sulfur oxide up-conversion luminescent material and a preparation method.

Background technique

In recent years, the improvement of the output power of near-infrared semiconductor laser diodes has provided an effective excitation pump source for up-conversion luminescent materials, and promoted the large-scale development of up-conversion luminescent materials. Infrared detection technology, anti-counterfeiting technology, biomolecular fluorescent labeling and solar cells have been applied in actual or potential fields. The host material is the main component of the up-conversion luminescent material, and its physical and chemical properties largely determine the overall performance of the up-conversion luminescent material. Due to its good thermal and chemical stability, sulfur oxide is suitable for doping ions with a band gap of 4.6-4.8eV, and its maximum phonon energy is 520cm ^-1 , so it is considered as a potential host for upconversion luminescent materials. Material.

There are many preparation methods for rare earth sulfur oxide up-conversion luminescent materials, among which the main advantage of the sulfur melting method is that it is suitable for large-scale industrial production, the crystal is complete, and the luminescence performance is better than that of products prepared by other methods. However, the reaction temperature of the sulfur melting method is relatively high, and the reaction temperature of products with good performance is usually as high as 1200 ° C, and the reaction process is not easy to control. At the same time, the amount and type of flux used in the sulfur melting method are not fixed, and there is no clear range at present. In addition, the oxide raw materials used in the sulfur melting method generally use the rare earth oxides purchased in the market directly. Without further optimization, the particle size is uneven and the agglomeration is serious, which will affect the particle properties of the rare earth sulfur oxide product.

In view of this, the present invention is proposed.

Contents of the invention

The first purpose of the present invention is to provide a Zn-enhanced rare earth oxysulfide up-conversion luminescent material to solve the problem of weak luminous intensity of existing rare-earth oxysulfide up-conversion luminescent materials. The Zn-enhanced rare earth oxysulfide For the up-conversion luminescent material, since Zn doping optimizes the crystal structure of the rare earth oxysulfide, the crystal structure symmetry and phonon energy are reduced, and the luminous intensity is greatly enhanced by 50% to 120%.

The second object of the present invention is to provide a preparation method of the Zn-enhanced rare earth sulfur oxide up-conversion luminescent material, the method adopts the method of precipitant reverse dripping to prepare rare earth oxide raw materials, so as to solve the problem of existing purchase of rare earth Oxide raw materials have uneven particle size and serious agglomeration problems. The prepared rare earth oxide raw materials have the advantages of spherical particles, uniform particle size, good dispersibility, no need for ball milling, and can be used directly. Then, the gas vulcanization method is used to replace the traditional sulfur melting method. The reaction conditions are simple and easy to control. This method can well maintain the morphology and particle size of rare earth oxides.

In order to realize the above-mentioned purpose of the present invention, special adopt following technical scheme:

A Zn-enhanced rare earth sulfur oxide up-conversion luminescent material, the chemical formula of the material is (Ln _{1-xy- z} Yb _x RE _y Zn _z ) ₂ O ₂ S, wherein 0.04≤x≤0.2, 0.005≤y≤0.02 , 0.005≤z≤0.02; where Ln is one of La, Y or Gd, and RE is one of Er, Ho, Tm, Pr, Eu or Tb.

Up-conversion luminescence is the continuous emission of light with a wavelength shorter than that of the excitation light under the excitation of long-wavelength light. Up-conversion luminescence is essentially a kind of anti-stocks luminescence, that is, the radiated energy is greater than the absorbed energy. Up-conversion materials are mainly solid compounds doped with rare earth elements. Using the metastable energy level characteristics of rare earth elements, they can absorb multiple low-energy long-wave radiations, thereby turning infrared light invisible to the human eye into visible light. Divalent Zn ²⁺ optimizes the crystal structure of rare earth oxysulfide in the up-conversion luminescent material of rare earth oxysulfide, which reduces the crystal structure symmetry and phonon energy, which is because Zn ²⁺ enters in the form of interstitial The crystal lattice of the rare earth oxysulfide produces lattice distortion, which changes the crystal field of the rare earth oxysulfide.

A preparation method of a Zn-enhanced rare earth oxysulfide up-conversion luminescent material, comprising the following steps:

(1) According to the chemical formula (Ln _1-xyz Yb _x RE _y Zn _z ) ₂ O ₂ S, weigh the required raw materials Ln(NO ₃ ) ₃ , Yb(NO ₃ ) ₃ , RE(NO ₃ ) ₃ and Zn( NO ₃ ) ₂ , dissolving the above raw materials to prepare a nitrate solution;

(2), the nitrate solution described in step (1) is dripped in the precipitating agent solution, and stir; After the titration finishes, continue to stir, and the solution after the titration is sealed, left to age, and filtered;

(3), after the precipitate filtered in step (2) is washed with deionized water and dried, the temperature of the precipitate is raised to 600-800 ° C, and then the temperature is lowered to room temperature;

(4) Mix the product after cooling down to room temperature in step (3) with sulfur element, then raise the temperature to 800-1000° C. in an inert gas atmosphere, and then lower the temperature to room temperature after keeping warm to obtain the Zn-enhanced rare earth sulfur oxide Up-converting luminescent materials.

When x, y and z select different values within the optional range, weigh the equimolar nitrates Ln(NO ₃ ) ₃ , Yb(NO ₃ ) ₃ , RE(NO ₃ ) ₃ and Zn(NO ₃ ) ₂ , prepare the precipitant solution, and then back-drop the nitrate solution into the precipitant solution. The amount of precipitant solution is determined according to the valence state of the anion in the precipitant and the moles of Ln(NO ₃ ) ₃ , Yb(NO ₃ ) ₃ , RE(NO ₃ ) ₃ and Zn(NO ₃ ) ₂ To ensure that the number of moles of anions in the precipitating agent and the number of moles of Ln(NO ₃ ) ₃ , Yb(NO ₃ ) ₃ , RE(NO ₃ ) ₃ and Zn(NO ₃ ) ₂ oxygen ions are in the same valence is trimmed to achieve charge balance. At this time, the precipitating agent is excessive, and the precipitation reaction is sufficient. After the reaction is completed, filter and clean the precipitate, raise the temperature to 600-800°C and keep it warm to help the formation of crystals and ensure the integrity of the crystal lattice. Then, according to the amount of raw materials weighed, measure an appropriate amount of sulfur element, mix and heat to 800-1000°C, and keep warm to ensure sufficient reaction.

The method provided by the invention adopts the gas vulcanization method, which is simpler and more convenient than the sulfur melting method, and the reaction conditions are easy to control.

Preferably, in step (1), the precipitating agent is oxalic acid, and the molar ratio of the oxalic acid to all metal elements in the up-conversion luminescent material is: 1: (1-1.5).

Metal ions and oxalic acid can form metal oxalate precipitation.

Preferably, in step (2), the time for continuing stirring is 0.5-1.5 h, and the time for standing and aging is 10-20 hours.

Stirring and aging operations can ensure that the reaction is fully carried out.

Preferably, in step (3), the number of times of washing with deionized water is 3-5 times.

Wash 3-5 times to remove excess impurities.

Preferably, in step (3), the drying temperature is 60-80°C.

Preferably, in step (3) and step (4), the temperature rise adopts a rapid temperature rise box-type resistance furnace, and the temperature rise rate is 3-5° C./min.

The heating rate plays a vital role in the crystal formation and surface morphology of luminescent materials. If the heating rate is too fast, the crystal growth will be too fast and the crystal morphology will not be uniform; if the heating rate is too slow, the efficiency and progress of the experiment will be slowed down.

Preferably, in step (3), the time of the heat preservation is 2-4 hours;

and / or;

In step (4), the time of the heat preservation is 3-5 hours.

Preferably, in step (4), the inert gas is one of nitrogen or argon.

Under the inert gas atmosphere, it can prevent the raw material from reacting with the oxygen in the air and affect the purity of the luminescent material.

Preferably, in step (4), the molar ratio of the sulfur element to the product is 5-7.

Compared with prior art, the beneficial effect of the present invention is:

(1) A Zn-enhanced rare earth oxysulfide up-conversion luminescent material provided by the present invention optimizes the crystal structure of the rare earth oxysulfide due to Zn doping, reduces crystal structure symmetry and phonon energy, and greatly improves luminous intensity Enhanced, increased by 50% to 120%.

(2) The preparation method of a Zn-enhanced rare earth sulfur oxide up-conversion luminescent material provided by the present invention adopts the method of precipitant reverse dripping to obtain the rare earth oxide raw material, and the prepared rare earth oxide raw material has particles that are spherical, particle It has the advantages of uniform size, good dispersion, no need for ball milling, and can be used directly.

(3) The preparation method of a Zn-enhanced rare earth oxysulfide up-conversion luminescent material provided by the present invention adopts the gas vulcanization method to replace the traditional sulfur melting method, the reaction conditions are simple and easy to control, and the method can well maintain rare earth The morphology and particle size of the oxide, the rare earth sulfur oxide up-conversion luminescent material prepared by this method is mostly spherical, the particle size is uniform, the particle distribution range is narrow, D ₉₀ =0.2-0.5μm, the product does not need ball milling, and can be Use directly.

Description of drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art.

Fig. 1 is the XRD spectrum of the product (La _0.775 Yb _0.2 Er _0.005 Zn _0.02 ) ₂ O ₂ S prepared in Example 2;

Fig. 2 is the SEM image of the product (La _0.775 Yb _0.2 Er _0.005 Zn _0.02 ) ₂ O ₂ S prepared in Example 2;

Figure 3 is the upconversion luminescence spectrum of the product (La _0.775 Yb _0.2 Er _0.005 Zn _0.02 ) ₂ O ₂ S prepared in Example 2;

Figure 4 is the upconversion luminescence spectrum of the product (La _0.8175 Yb _0.16 Ho _0.0075 Zn _0.015 ) ₂ O ₂ S prepared in Example 3;

Figure 5 is the upconversion luminescence spectrum of the product (Y _0.8575 Yb _0.12 Tm _0.01 Zn _0.0125 ) ₂ O ₂ S prepared in Example 4;

Figure 6 is the upconversion luminescence spectrum of the product (Y _0.8775 Yb _0.1 Pr _0.0125 Zn _0.01 ) ₂ O ₂ S prepared in Example 5;

Figure 7 is the upconversion luminescence spectrum of the product (Gd _0.8975 Yb _0.08 Eu _0.015 Zn _0.0075 ) ₂ O ₂ S prepared in Example 6;

Fig. 8 is the upconversion luminescence spectrum of the product (Gd _0.935 Yb _0.04 Tb _0.02 Zn _0.005 ) ₂ O ₂ S prepared in Example 7.

detailed description

Embodiments of the present invention will be described in detail below in conjunction with examples, but those skilled in the art will understand that the following examples are only for illustrating the present invention, and should not be considered as limiting the scope of the present invention. Those who do not indicate the specific conditions in the examples are carried out according to the conventional conditions or the conditions suggested by the manufacturer. The reagents or instruments used were not indicated by the manufacturer, and they were all conventional products that could be purchased from the market.

Example 1

A Zn-enhanced rare earth sulfur oxide up-conversion luminescent material, the chemical formula of which is (La _0.8175 Yb _0.16 Ho _0.0075 Zn _0.015 ) ₂ O ₂ S.

The preparation method of the rare earth sulfur oxide up-conversion luminescent material comprises the following steps:

S11. According to the chemical formula (La _0.8175 Yb _0.16 Ho _0.0075 Zn _0.015 ) ₂ O ₂ S, weigh the required raw materials 20.171g La(NO ₃ ) ₃ 6H ₂ O, 4.095g Yb(NO ₃ ) ₃ 5H ₂ O, 0.187g Ho(NO ₃ ) ₃ ·5H ₂ O and 0.254g Zn(NO ₃ ) ₂ ·6H ₂ O, dissolve the above raw materials to prepare a nitrate solution; according to the amount of raw materials, weigh 7.902g of oxalic acid, and prepare into oxalic acid solution;

S12. Drop the nitrate solution described in step S11 into the precipitant solution, and stir; after the titration, continue to stir, and seal the titrated solution, leave it to age, and filter;

S13. Wash and dry the precipitate filtered in step S12 with deionized water, then raise the temperature of the washed precipitate to 650° C., keep it warm and lower it to room temperature;

S14. Mix the product cooled to room temperature in step S13 with sulfur element, then raise the temperature to 850° C. in an inert gas atmosphere, keep warm and lower to room temperature to obtain 10 g of the Zn-enhanced rare earth sulfur oxide up-conversion luminescent material.

Example 2

A Zn-enhanced rare earth sulfur oxide up-conversion luminescent material, the chemical formula of which is (La _0.775 Yb _0.2 Er _0.005 Zn _0.02 ) ₂ O ₂ S.

The preparation method of the rare earth sulfur oxide up-conversion luminescent material comprises the following steps:

S21. According to the chemical formula (La _0.775 Yb _0.2 Er _0.005 Zn _0.02 ) ₂ O ₂ S, weigh the required raw materials 19.020g La(NO ₃ ) ₃ 6H ₂ O, 5.091g Yb(NO ₃ ) ₃ 5H ₂ O, 0.126g Er(NO ₃ ) ₃ ·5H ₂ O and 0.337g Zn(NO ₃ ) ₂ ·6H ₂ O, the above raw materials were dissolved to prepare a nitrate solution; according to the amount of raw materials, 7.145g oxalic acid was weighed and prepared into oxalic acid solution;

S22. Drop the nitrate solution described in step S21 into the oxalic acid solution, and stir; after the titration, continue to stir for 0.5 hours, seal the titrated solution, leave it to age for 10 hours, and filter;

S23. Wash the precipitate filtered in step S22 three times with deionized water, dry it at 60° C., and then heat the washed precipitate to 600° C. at a rate of 3° C./min in a box-type resistance furnace with rapid temperature rise. , down to room temperature after 2 hours of heat preservation;

S24. Mix the product that was lowered to room temperature in step S23 with 4.543 g of sulfur elemental substance, and then in a nitrogen atmosphere, use a fast heating box-type resistance furnace to heat up to 800° C. at a rate of 5° C./min, and keep it for 3 hours. After cooling down to room temperature, 10 g of the Zn-enhanced rare earth oxysulfide up-conversion luminescent material was obtained.

Example 3

A Zn-enhanced rare earth sulfur oxide up-conversion luminescent material, the chemical formula of which is (La _0.8175 Yb _0.16 Ho _0.0075 Zn _0.015 ) ₂ O ₂ S.

The preparation method of the rare earth sulfur oxide up-conversion luminescent material comprises the following steps:

S31. According to the chemical formula (La _0.8175 Yb _0.16 Ho _0.0075 Zn _0.015 ) ₂ O ₂ S, weigh the required raw materials 20.171g La(NO ₃ ) ₃ 6H ₂ O, 4.095g Yb(NO ₃ ) ₃ 5H ₂ O, 0.187g Ho(NO ₃ ) ₃ ·5H ₂ O and 0.254g Zn(NO ₃ ) ₂ ·6H ₂ O, the above raw materials were dissolved to prepare a nitrate solution; according to the amount of raw materials, 7.902g oxalic acid was weighed and prepared into Oxalic acid solution;

S32. Drop the nitrate solution described in step S31 into the oxalic acid solution, and stir; after the titration, continue to stir for 1 hour, seal the titrated solution, leave it to age for 12 hours, and filter;

S33. Wash the precipitate filtered in step S32 four times with deionized water, dry it at 70°C, and then heat the washed precipitate to 650°C at a rate of 3.5°C/min in a fast heating box-type resistance furnace , down to room temperature after 3 hours of heat preservation;

S34, then mix the product cooled to room temperature in step S33 with 5.025 g of sulfur element, and then in an argon atmosphere, use a fast heating box-type resistance furnace to raise the temperature to 850°C at a rate of 4.5°C/min, and keep it warm for 4 hours After cooling down to room temperature, 10 g of the Zn-enhanced rare earth oxysulfide up-conversion luminescent material was obtained.

Example 4

A Zn-enhanced rare earth sulfur oxide up-conversion luminescent material, the chemical formula of which is (Y _0.8575 Yb _0.12 Tm _0.01 Zn _0.0125 ) ₂ O ₂ S.

The preparation method of the rare earth sulfur oxide up-conversion luminescent material comprises the following steps:

S41. According to the chemical formula (Y _0.8575 Yb _0.12 Tm _0.01 Zn _0.0125 ) ₂ O ₂ S, weigh 24.968g Y(NO ₃ ) ₃ 6H ₂ O, 4.097g Yb(NO ₃ ) ₃ 5H ₂ O, 0.270g Tm(NO ₃ ) ₃ and 0.283g Zn(NO ₃ ) ₂ 6H ₂ O, the above raw materials were dissolved to prepare a nitrate solution; according to the amount of raw materials, 11.50g oxalic acid was weighed and prepared into an oxalic acid solution;

S42, drop the nitrate solution described in step S41 into the oxalic acid solution, and stir; after the titration, continue to stir for 1.5 hours, and seal the titrated solution, leave it to age for 14 hours, and filter;

S43. Wash the filtered precipitate in step S42 with deionized water for 5 times, dry it at 80°C, and then heat the washed precipitate to 700°C at a rate of 4°C/min by using a fast heating box-type resistance furnace , down to room temperature after 4 hours of heat preservation;

S44. Mix the product cooled to room temperature in step S43 with 7.413 g of sulfur element, and then in a nitrogen atmosphere, use a fast heating box-type resistance furnace to heat up to 900° C. at a rate of 4° C./min. After 5 hours of heat preservation After cooling down to room temperature, 10 g of the Zn-enhanced rare earth oxysulfide up-conversion luminescent material was obtained.

Example 5

A Zn-enhanced rare earth sulfur oxide up-conversion luminescent material, the chemical formula of which is (Y _0.8775 Yb _0.1 Pr _0.0125 Zn _0.01 ) ₂ O ₂ S.

The preparation method of the rare earth sulfur oxide up-conversion luminescent material comprises the following steps:

S51. According to the chemical formula (Y _0.8775 Yb _0.1 Pr _0.0125 Zn _0.01 ) ₂ O ₂ S, weigh 25.899g Y(NO ₃ ) ₃ 6H ₂ O, 3.461g Yb(NO ₃ ) ₃ 5H ₂ O, 0.419g Pr(NO ₃ ) ₃ and 0.229g Zn(NO ₃ ) ₂ ·6H ₂ O, dissolve the above raw materials, stir evenly, and prepare nitrate solution; according to the amount of raw materials, weigh 12.629g oxalic acid, and prepare Oxalic acid solution, stir evenly;

S52. Drop the nitrate solution described in step S51 into the oxalic acid solution, and stir; after the titration, continue to stir for 0.5 hours, seal the titrated solution, leave it to age for 16 hours, and filter;

S53. Wash the precipitate filtered in step S52 with deionized water three times, dry it at 60°C, and then heat the washed precipitate to 700°C at a rate of 4°C/min by using a fast heating box-type resistance furnace , down to room temperature after 2 hours of heat preservation;

S54. Mix the product cooled to room temperature in step S53 with 7.413 g of sulfur element, and then in an argon atmosphere, use a fast heating box-type resistance furnace to heat up to 900° C. at a rate of 4° C./min, and keep the temperature for 3 hours. After cooling down to room temperature, 10 g of the Zn-enhanced rare earth oxysulfide up-conversion luminescent material was obtained.

Example 6

A Zn-enhanced rare earth sulfur oxide up-conversion luminescent material, the chemical formula of which is (Gd _0.8975 Yb _0.08 Eu _0.015 Zn _0.0075 ) ₂ O ₂ S.

The preparation method of the rare earth sulfur oxide up-conversion luminescent material comprises the following steps:

S61. According to the chemical formula (Gd _0.8975 Yb _0.08 Eu _0.015 Zn _0.0075 ) ₂ O ₂ S, weigh the required raw materials 21.345g Gd(NO ₃ ) ₃ 6H ₂ O, 1.893g Yb(NO ₃ ) ₃ 5H ₂ O, 0.353g Eu(NO ₃ ) ₃ 6H ₂ O and 0.118g Zn(NO ₃ ) ₂ 6H ₂ O, dissolve the above raw materials, stir evenly, and prepare nitrate solution; according to the amount of raw materials, weigh 9.30g oxalic acid , and prepared into an oxalic acid solution, and stirred evenly;

S62, drop the nitrate solution described in step S61 into the oxalic acid solution, and stir; after the titration, continue to stir for 1 hour, and seal the titrated solution, leave it to age for 18 hours, and filter;

S63. Wash the filtered precipitate in step S62 with deionized water for 4 times, dry it at 70°C, and then heat the washed precipitate to 750°C at a rate of 4.5°C/min in a fast heating box-type resistance furnace , down to room temperature after 3 hours of heat preservation;

S64, then mix the product cooled to room temperature in step S63 with 5.491 g of sulfur element, and then in a nitrogen atmosphere, use a fast heating box-type resistance furnace to raise the temperature to 950° C. at a rate of 3.5° C./min, and keep it for 4 hours. After cooling down to room temperature, 10 g of the Zn-enhanced rare earth oxysulfide up-conversion luminescent material was obtained.

Example 7

A Zn-enhanced rare earth sulfur oxide up-conversion luminescent material, the chemical formula of which is (Gd _0.935 Yb _0.04 Tb _0.02 Zn _0.005 ) ₂ O ₂ S.

The preparation method of the rare earth sulfur oxide up-conversion luminescent material comprises the following steps:

S71. According to the chemical formula (Gd _0.935 Yb _0.04 Tb _0.02 Zn _0.005 ) ₂ O ₂ S, weigh the required raw materials 22.271g Gd(NO ₃ ) ₃ 6H ₂ O, 0.948g Yb(NO ₃ ) ₃ 5H ₂ O, 0.478g Tb(NO ₃ ) ₃ 6H ₂ O and 0.078g Zn(NO ₃ ) ₂ 6H ₂ O, dissolve the above raw materials, stir evenly, and prepare nitrate solution; according to the amount of raw materials, weigh 9.979g oxalic acid , and prepared into an oxalic acid solution, and stirred evenly;

S72, drop the nitrate solution described in step S71 into the oxalic acid solution, and stir; after the titration, continue to stir for 1.5 hours, seal the titrated solution, leave it to age for 20 hours, and filter;

S73. Wash the precipitate filtered in step S72 with deionized water for 5 times, dry it at 80°C, and then heat the washed precipitate to 800°C at a rate of 5°C/min by using a fast heating box-type resistance furnace , down to room temperature after 4 hours of heat preservation;

S74, then mix the product cooled to room temperature in step S73 with 5.923 g of sulfur elemental substance, and then in an argon atmosphere, use a fast heating box-type resistance furnace to heat up to 1000°C at a rate of 3°C/min, and keep it warm for 5 hours After cooling down to room temperature, 10 g of the Zn-enhanced rare earth oxysulfide up-conversion luminescent material was obtained.

Experimental example 1 Phase composition, morphology and particle size analysis of Zn-enhanced rare earth oxysulfide up-conversion luminescent material

For the Zn-enhanced rare earth oxysulfide up-conversion luminescent material provided in Examples 1-7, the phase composition analysis was carried out with an X-ray diffractometer (XRD, D/Max2500), and a scanning electron microscope (SEM, JEOL-6310) was used to analyze the phase composition. For particle size and shape analysis, software was used for particle size statistics, and the _D90 statistical results are shown in Table 1.

Table 1 embodiment 1-7D ₉₀ statistical results

Experiments have proved that the XRD spectrum of the Zn-enhanced rare-earth sulfur oxide up-conversion luminescent material provided by the present invention shows that the positions of the main diffraction peaks are all corresponding to the hexagonal rare-earth sulfur oxide, and there are no peaks of other material phases. Among them, Figure 1 The XRD spectrum of the product (La _0.775 Yb _0.2 Er _0.005 Zn _0.02 ) ₂ O ₂ S prepared for Example 2; the particle size and morphology analysis was carried out with a scanning electron microscope (SEM, JEOL-6310), and the results showed that the particle morphology It is spherical and the particles are evenly distributed. Figure 2 is the SEM picture of the product (La _0.775 Yb _0.2 Er _0.005 Zn _0.02 ) ₂ O ₂ S prepared in Example 2; the particle size statistics are performed using software, D ₉₀ =0.20-0.50 μm.

Experimental example 2 Luminescence performance test of Zn-enhanced rare earth oxysulfide up-conversion luminescent material

The up-conversion luminescence performance test was carried out with a fluorescence spectrometer (PL, FL3-221), and the result compared with the sample without Zn doping, the degree of luminescence intensity improvement is shown in Table 2.

Table 2 embodiment 1-7 luminous intensity improvement degree

Experiments have proved that because Zn doping optimizes the crystal structure of the rare earth oxysulfide, reduces crystal structure symmetry and phonon energy, and greatly enhances the luminous intensity by 50% to 120%. Among them, Figures 3-8 are the up-conversion luminescence spectra of Examples 2-7.

In summary, a Zn-enhanced rare earth oxysulfide up-conversion luminescent material provided by the present invention optimizes the crystal structure of the rare earth oxysulfide due to Zn doping, reduces the crystal structure symmetry and phonon energy, and emits light. The strength is greatly enhanced by 50% to 120%. The preparation method of a Zn-enhanced rare earth sulfur oxide up-conversion luminescent material provided by the present invention adopts the method of back-dropping the precipitant to obtain the rare earth oxide raw material, and the prepared rare earth oxide raw material has spherical particles, uniform particle size, Good dispersibility, no need for ball milling, and direct use; this preparation method uses gas vulcanization instead of the traditional sulfur melting method, and the reaction conditions are simple and easy to control. This method can well maintain the morphology and shape of rare earth oxides. Particle size. The rare earth sulfur oxide up-conversion luminescent material prepared by this method is mostly spherical, with uniform particle size and narrow particle distribution range, D ₉₀ =0.2-0.5 μm. The product does not need ball milling and can be used directly.

While particular embodiments of the invention have been illustrated and described, it should be appreciated that various other changes and modifications can be made without departing from the spirit and scope of the invention. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this invention.

Claims (10)

1. a kind of enhanced rare-earth oxide sulfate up-conversion luminescent material of Zn, it is characterised in that the chemical formula of the material is (Ln_1-x-y-zYb_xRE_yZn_z)₂O₂S, wherein 0.04≤x≤0.2,0.005≤y≤0.02,0.005≤z≤0.02；Wherein Ln is One kind in La, Y or Gd, RE is one kind in Er, Ho, Tm, Pr, Eu or Tb.

2. a kind of preparation method of the enhanced rare-earth oxide sulfate up-conversion luminescent material of Zn according to claim 1, its It is characterised by, comprises the following steps：

(1), by chemical formula (Ln_1-x-y-zYb_xRE_yZn_z)₂O₂Raw material Ln (NO needed for S is weighed₃)₃、Yb(NO₃)₃、RE(NO₃)₃And Zn (NO₃)₂, above-mentioned raw materials are dissolved, nitrate solution is configured to；

(2), the nitrate solution described in step (1) is instilled in precipitant solution, and stirred；After titration terminates, continue to stir, And by after titration solution sealing, it is still aging, filtering；

(3) after, the precipitation after filtering in step (2) is washed with deionized, dried, precipitation is warming up to 600-800 DEG C, then Room temperature is down to after insulation；

(4), the product after room temperature will be down in step (3) to mix with sulphur simple substance, is then warming up in atmosphere of inert gases 800-1000 DEG C, then room temperature is down to after being incubated, obtain the enhanced rare-earth oxide sulfate up-conversion luminescent materials of the Zn.

3. the preparation method of the enhanced rare-earth oxide sulfate up-conversion luminescent material of Zn according to claim 2, its feature It is, in step (1), the precipitating reagent is oxalic acid, and the oxalic acid and all metals in the up-conversion luminescent material are first Element mol ratio be：1：(1-1.5).

4. the preparation method of the enhanced rare-earth oxide sulfate up-conversion luminescent material of Zn according to claim 2, its feature It is, in step (2), the time for continuing to stir is 0.5-1.5 hours, and the still aging time is that 10-20 is small When.

5. the preparation method of the enhanced rare-earth oxide sulfate up-conversion luminescent material of Zn according to claim 2, its feature It is, in step (3), the number of times being washed with deionized is 3-5 times.

6. the preparation method of the enhanced rare-earth oxide sulfate up-conversion luminescent material of Zn according to claim 2, its feature It is, in step (3), the temperature of the drying is 60-80 DEG C.

7. the preparation method of the enhanced rare-earth oxide sulfate up-conversion luminescent material of Zn according to claim 2, its feature It is, in step (3) and step (4), the heating is using the chamber type electric resistance furnace that is rapidly heated, and heating rate is 3-5 DEG C/minute Clock.

8. the preparation method of the enhanced rare-earth oxide sulfate up-conversion luminescent material of Zn according to claim 2, its feature It is, in step (3), the time of the insulation is 2-4 hours；

And/or；

In step (4), the time of the insulation is 3-5 hours.

9. the preparation method of the enhanced rare-earth oxide sulfate up-conversion luminescent material of Zn according to claim 2, its feature It is, in step (4), the inert gas is one kind in nitrogen or argon gas.

10. the preparation method of the enhanced rare-earth oxide sulfate up-conversion luminescent material of Zn according to claim 2, its feature It is, in step (4), the mol ratio of the sulphur simple substance and the product is 5-7.