CN101831292A - Strontium aluminate luminous material and controllable synthesis method thereof - Google Patents

Abstract

The invention discloses an aluminate luminescent material and a controllable synthesis method thereof. The present invention uses Al(NO ₃ ) ₃ ·9H ₂ O, Sr(NO ₃ ) ₂ , CO(NH ₂ ) ₂ , C ₆ H ₅ Na ₃ O ₇ ·2H ₂ O, Eu ₂ O ₃ , Dy ₂ O ₃ , HNO ₃ as raw material, the method is hydrothermal synthesis-calcination two-step method: (1) Dissolve Sr(NO ₃ ) ₂ , Al(NO ₃ ) ₃ 9H ₂ O in distilled water respectively to form a nitrate solution. Take the above-mentioned nitrate solution, mix it well, then add europium nitrate and dysprosium nitrate, mix it with a certain proportion of CO(NH ₂ ) ₂ or surfactant and put it in a closed reaction kettle, stir and dissolve it in Precursors are obtained by keeping the temperature at a certain temperature for several hours; (2) After the precursors are filtered and dried, they are annealed in air atmosphere and reducing atmosphere at different temperatures for several hours to prepare nano-aluminate luminescent materials. The invention proposes to prepare the strontium aluminate luminescent material by a two-step method of hydrothermal synthesis and calcination, which can effectively control the product form and luminous color, has good dispersibility, and expands the application field of the luminescent material.

Description

A strontium aluminate luminescent material and its controllable synthesis method

technical field

The invention relates to a preparation method of a nano-luminescent material, specifically a strontium aluminate luminescent material.

Background technique

Rare-earth ion-doped inorganic phosphors have attracted widespread attention due to their extraordinary luminescent properties and applications, and can be used in many aspects such as lighting industry, radiation dose, X-ray imaging and color display. Compared with luminescent materials based on sulfide, europium-doped strontium aluminate shows good stability, long afterglow time and high quantum efficiency. In the SrO-Al ₂ O ₃ system, many non-stoichiometric compounds exist, such as Sr ₃ Al ₂ O ₆ , SrAl ₂ O ₄ , Sr ₄ Al ₄ O ₂₅ , SrAl ₄ O ₇ and SrAl ₁₂ O ₁₉ . The current preparation status is high-temperature solid-phase synthesis (SrCO ₃ and Al ₂ O ₃ ). Although the preparation method is simple, the particles of the prepared product are relatively coarse and the luminous efficiency is not high; the purity and luminescent performance of the product prepared by the combustion method are still to be determined. Improve; the product particle that sol-gel method makes is fine and uniform, but because sol needs 50-75 hours to change into gel time, the production cycle is too long, is unfavorable for industrialized large-scale production.

After literature search, it was found that the Chinese patent (publication number CN1840610A) discloses a strontium aluminate long-lasting luminescent material whose chemical composition is Sr ₂ AAl _2B O ₈ :Eu ²⁺ , Dy ³⁺ , where A is 1.5-3 , B is 1.0; the preparation method is to adopt the sol-gel method, sol at 80-100 ℃, then dehydrate the sol to form a gel, and then anneal it in a protective gas at 1200-1400 ℃ for 2-4 hours, The red strontium aluminate long afterglow material was prepared. This preparation method can only produce long afterglow materials that emit red light; in addition, the annealing temperature is as high as 1400 ° C, which easily affects the morphology of the material.

Contents of the invention

The present invention aims to provide a strontium aluminate luminescent material with controllable appearance and controllable luminous color and a mild and controllable synthesis method thereof, so as to solve the deficiencies in the prior art.

A nano-strontium aluminate luminescent material, characterized in that:

The chemical formula of the luminescent material is: Sr _3-xy Al ₂ O ₆ : x Eu ²⁺ (Eu ³⁺ ), y Dy ³⁺ (0<x≤0.02, 0<y≤0.04); wherein, Sr is strontium , Al is aluminum, O is oxygen, Eu ²⁺ (Eu ³⁺ ) is europium ions, Dy ³⁺ is dysprosium ions, that is, the luminescent material is strontium aluminate co-doped with europium and dysprosium ions.

The controllable synthesis method of nano-strontium aluminate luminescent material is characterized in that it is a two-step method of hydrothermal synthesis-calcination, and is operated according to the following steps and feeding ratio:

(1) Weigh 0.005 to 0.007 moles of aluminum nitrate, 0.008 to 0.0095 moles of strontium nitrate, 0.000015 to 0.000025 moles of europium nitrate, 0.000025 to 0.000035 moles of dysprosium nitrate, and 0.015 to 0.025 moles of urea in a reaction vessel, and then add 40 to 50 ml of distilled water, stirred and dissolved, put the above solution in a closed reaction kettle, and kept it at 120°C-200°C for 10-14 hours to obtain a white product;

(2) filter and wash the cooled white product with distilled water and ethanol respectively, and dry at 50-70° C. for 5-6 hours to obtain the precursor;

(3) annealing the precursor in an air atmosphere or a reducing atmosphere at 900-1200° C. for 2-4 hours to prepare a strontium aluminate luminescent material.

The controllable synthesis method of nano-strontium aluminate luminescent material is characterized in that it operates according to the following steps and feeding ratio:

(1) Weigh 0.006 moles of aluminum nitrate, 0.009 moles of strontium nitrate, 0.00002 moles of europium nitrate, 0.00003 moles of dysprosium nitrate, and 0.02 moles of urea in a reaction vessel, then add 40 to 50 milliliters of distilled water to it, stir to dissolve, and dissolve the above solution Put it in a closed reaction kettle and keep it warm at 120°C-200°C for 10-14 hours to obtain a white product;

(2) filter and wash the cooled white product with distilled water and ethanol, and dry it at 50-70° C. for 5-6 hours to obtain a precursor;

(3) annealing the precursor in an air atmosphere or a reducing atmosphere at 900-1200° C. for 2-4 hours to prepare a strontium aluminate luminescent material.

The controllable synthesis method of the nano-strontium aluminate luminescent material is characterized in that 0.03 mole of sodium citrate is added in step (1) to control the shape of the strontium aluminate to be spherical.

The controllable synthesis method of nanometer strontium aluminate luminescent material is characterized in that Al(NO ₃ ) ₃ 9H ₂ O , Sr(NO ₃ ) ₂ , Eu(NO ₃ ) ₃ , Dy(NO ₃ ) ₃ , CO(NH ₂ ) ₂ , C ₆ H ₅ Na ₃ O ₇ ·2H ₂ O.

The controllable synthesis method of the nano-strontium aluminate luminescent material is characterized in that the reducing atmosphere is a mixed gas composed of 5-20% hydrogen and 80-95% argon.

Compared with the beneficial effects of the prior art, firstly, the phase analysis of the prepared luminescent material is carried out by using an X-ray diffractometer. From the obtained X-ray diffraction pattern, it can be seen that the chemical formula of the material is Sr ₃ Al ₂ O ₆ : Eu ²⁺ (Eu ³⁺ ), Dy ³⁺ ; Second, analyze the morphology of the obtained powder using a field emission scanning electron microscope. From the obtained electron microscope photos, it can be seen that the morphology change of the strontium aluminate material Process: When the precursor is calcined at 900°C, the sample is composed of many one-dimensional nanostructures, and a large number of synapses grow on its surface; when the calcination temperature is increased to 1000°C, the synapses begin to transform into nanorods, forming New layered structure; when the calcination temperature continued to increase to 1100 °C, the layered structure disappeared and some defective one-dimensional nanorods appeared; finally, pure irregularly shaped strontium aluminate luminescence was obtained at 1200 °C Materials; and the shape of the precursor: the precursor without sodium citrate is rod-shaped, and the precursor with sodium citrate is spherical; third, use photoluminescence analysis on the prepared powder, from the emission and excitation spectra It can be seen from the figure that materials excited by different wavelength bands can emit light of different colors; fourthly, the hydrothermal synthesis method lowers the synthesis temperature than the conventional sol-gel method, which greatly saves energy consumption; finally, the hydrothermal synthesis prepared The method is simple, easy to operate and low in cost.

Description of drawings

The preferred modes of the present invention will be further described in detail below in conjunction with the accompanying drawings.

Fig. 1 X-ray diffraction pattern of luminescent material calcined at 900-1200°C under air atmosphere. Among them, * stands for Sr ₃ Al ₂ O ₆ (JCPDS Card No.24-1187), # stands for SrCO ₃ (JCPDS Card No.05-0418), & stands for unidentified phase.

Fig. 2 X-ray diffraction pattern of luminescent material calcined at 900-1200°C under reducing atmosphere. Among them, * stands for Sr ₃ Al ₂ O ₆ (JCPDS Card No.24-1187), & stands for SrCO ₃ (JCPDS Card No.05-0418), $ stands for SrAl ₂ O ₄ (JCPDS Card No.34-0379), # It stands for Sr(OH) ₂ ·H ₂ O (JCPDS Card No.22-1222), and Ψ stands for undetermined phase.

Fig. 3 Field emission scanning electron micrographs of luminescent materials calcined at 900-1200°C under air atmosphere.

Fig. 4 is a field emission scanning electron micrograph of a luminescent material baked at 900-1200°C under a reducing atmosphere.

Fig. 5 is the field emission scanning electron micrograph of the precursor after adding sodium citrate and the field emission scanning electron micrograph of the luminescent material calcined at 1200° C. in air and reducing atmosphere.

Figure 6 Excitation and emission spectra of red strontium aluminate luminescent material.

Figure 7 Excitation and emission spectra of red and green strontium aluminate luminescent materials.

Figure 8 is the afterglow decay curve obtained after irradiating the red luminescent material with a xenon lamp with a wavelength of 440nm and 430nm for 10 minutes.

Detailed ways

Example 1: The preparation steps are as follows, 1), 0.006 moles of aluminum nitrate Al(NO ₃ ) ₃ ·9H ₂ O, 0.009 moles of strontium nitrate Sr(NO ₃ ) ₂ , 0.00002 moles of europium nitrate Eu(NO ₃ ) ₃ , 0.00003 One mole of dysprosium nitrate Dy(NO ₃ ) ₃ and 0.02 mole of urea CO(NH ₂ ) ₂ were put in a beaker, then 40-50 ml of distilled water was added thereto, stirred and dissolved, and the above solution was placed in a closed reaction kettle, at 120 At ~200°C for 10-14 hours, a white product was obtained. 2) The cooled white product is filtered and washed with distilled water and ethanol, and dried at 50-70° C. for 5-6 hours to obtain a precursor. 3) Annealing the precursor in an air atmosphere at 900° C. for 2 to 4 hours to prepare the strontium aluminate luminescent material as shown in Fig. 1(a) and Fig. 3(a).

Example 2: The preparation steps are as follows, 1), 0.006 moles of aluminum nitrate Al(NO ₃ ) ₃ 9H ₂ O, 0.009 moles of strontium nitrate Sr(NO ₃ ) ₂ , 0.00002 moles of europium nitrate Eu(NO ₃ ) ₃ , 0.00003 One mole of dysprosium nitrate Dy(NO ₃ ) ₃ and 0.02 mole of urea CO(NH ₂ ) ₂ were put in a beaker, and then 40-60 ml of distilled water was added thereto, stirred and dissolved, and the above solution was placed in a closed reaction kettle, at 120 At ~200°C for 10-14 hours, a white product was obtained. 2) The cooled white product is filtered and washed with distilled water and ethanol, and dried at 50-70° C. for 5-6 hours to obtain a precursor. 3) Annealing the precursor in an air atmosphere at 1000° C. for 2 to 4 hours to prepare the strontium aluminate luminescent material as shown in FIG. 1( b ) and FIG. 3 ( b ).

Example 3: The preparation steps are as follows, 1), 0.006 moles of aluminum nitrate Al(NO ₃ ) ₃ ·9H ₂ O, 0.009 moles of strontium nitrate Sr(NO ₃ ) ₂ , 0.00002 moles of europium nitrate Eu(NO ₃ ) ₃ , 0.00003 One mole of dysprosium nitrate Dy(NO ₃ ) ₃ and 0.02 mole of urea CO(NH ₂ ) ₂ were put in a beaker, then 40-50 ml of distilled water was added thereto, stirred and dissolved, and the above solution was placed in a closed reaction kettle, at 120 At ~200°C for 10-14 hours, a white product was obtained. 2) The cooled white product is filtered and washed with distilled water and ethanol, and dried at 50-70° C. for 5-6 hours to obtain a precursor. 3) Annealing the precursor in an air atmosphere at 1100° C. for 2 to 4 hours to prepare the strontium aluminate luminescent material as shown in Fig. 1(c) and Fig. 3(c).

Example 4: The preparation steps are as follows, 1), 0.006 moles of aluminum nitrate Al(NO ₃ ) ₃ ·9H ₂ O, 0.009 moles of strontium nitrate Sr(NO ₃ ) ₂ , 0.00002 moles of europium nitrate Eu(NO ₃ ) ₃ , 0.00003 One mole of dysprosium nitrate Dy(NO ₃ ) ₃ and 0.02 mole of urea CO(NH ₂ ) ₂ were put in a beaker, then 40-50 ml of distilled water was added thereto, stirred and dissolved, and the above solution was placed in a closed reaction kettle, at 120 At ~200°C for 10-14 hours, a white product was obtained. 2) The cooled white product is filtered and washed with distilled water and ethanol, and dried at 50-70°C for 5-6 hours to obtain the precursor shown in Figure 5(a). 3) Anneal the precursor in an air atmosphere at 1200°C for 2 to 4 hours to prepare alumina as shown in Figure 1(d), Figure 3(d), and Figure 6(a ₂ , b ₂ ). Strontium luminescent material.

Example 5: The preparation steps are as follows, 1), 0.006 moles of aluminum nitrate Al(NO ₃ ) ₃ ·9H ₂ O, 0.009 moles of strontium nitrate Sr(NO ₃ ) ₂ , 0.00002 moles of europium nitrate Eu(NO ₃ ) ₃ , 0.00003 One mole of dysprosium nitrate Dy(NO ₃ ) ₃ and 0.02 mole of urea CO(NH ₂ ) ₂ were put in a beaker, then 40-50 ml of distilled water was added thereto, stirred and dissolved, and the above solution was placed in a closed reaction kettle, at 120 At ~200°C for 10-14 hours, a white product was obtained. 2) The cooled white product is filtered and washed with distilled water and ethanol, and dried at 50-70° C. for 5-6 hours to obtain a precursor. 3), annealing the precursor in a reducing atmosphere at 900° C. for 2 to 4 hours; wherein, the reducing gas is a mixture of 5-20% hydrogen and 80-95% argon, as shown in Figure 2 ( a), the strontium aluminate luminescent material shown in Fig. 4(a).

Example 6: The preparation steps are as follows, 1), 0.006 moles of aluminum nitrate Al(NO ₃ ) ₃ ·9H ₂ O, 0.009 moles of strontium nitrate Sr(NO ₃ ) ₂ , 0.00002 moles of europium nitrate Eu(NO ₃ ) ₃ , 0.00003 One mole of dysprosium nitrate Dy(NO ₃ ) ₃ and 0.02 mole of urea CO(NH ₂ ) ₂ were put in a beaker, then 40-50 ml of distilled water was added thereto, stirred and dissolved, and the above solution was placed in a closed reaction kettle, at 120 At ~200°C for 10-14 hours, a white product was obtained. 2) The cooled white product is filtered and washed with distilled water and ethanol, and dried at 50-70° C. for 5-6 hours to obtain a precursor. 3), annealing the precursor in a reducing atmosphere at 1000° C. for 2 to 4 hours; wherein, the reducing gas is a mixture of 5-20% hydrogen and 80-95% argon, as shown in Figure 2 ( b), the strontium aluminate luminescent material shown in Fig. 4(b).

Example 7: The preparation steps are as follows, 1), 0.006 moles of aluminum nitrate Al(NO ₃ ) ₃ ·9H ₂ O, 0.009 moles of strontium nitrate Sr(NO ₃ ) ₂ , 0.00002 moles of europium nitrate Eu(NO ₃ ) ₃ , 0.00003 Put 1 mole of dysprosium nitrate Dy(NO ₃ ) ₃ and 0.02 mole of urea CO(NH ₂ ) ₂ in a beaker, then add 40-50 ml of distilled water to it, stir and dissolve, put the above solution in a closed reaction kettle, and heat it at 120- The white product was obtained by incubating at 200°C for 10-14 hours. 2) The cooled white product is filtered and washed with distilled water and ethanol, and dried at 50-70° C. for 5-6 hours to obtain a precursor. 3), annealing the precursor in a reducing atmosphere at 1100° C. for 2 to 4 hours; wherein, the reducing gas is a mixture of 5-20% hydrogen and 80-95% argon, as shown in Figure 2 ( c), the strontium aluminate luminescent material shown in Fig. 4(c).

Example 8: The preparation steps are as follows, 1), 0.006 moles of aluminum nitrate Al(NO ₃ ) ₃ ·9H ₂ O, 0.009 moles of strontium nitrate Sr(NO ₃ ) ₂ , 0.00002 moles of europium nitrate Eu(NO ₃ ) ₃ , 0.00003 One mole of dysprosium nitrate Dy(NO ₃ ) ₃ and 0.02 mole of urea CO(NH ₂ ) ₂ were put in a beaker, then 40-50 ml of distilled water was added thereto, stirred and dissolved, and the above solution was placed in a closed reaction kettle, at 120 At ~200°C for 10-14 hours, a white product was obtained. 2) The cooled white product is filtered and washed with distilled water and ethanol, and dried at 50-70° C. for 5-6 hours to obtain a precursor. 3), annealing the precursor in a reducing atmosphere at 1200° C. for 2 to 4 hours; wherein, the reducing gas is a mixture of 5-20% hydrogen and 80-95% argon, as shown in Figure 2 ( d), the strontium aluminate luminescent material shown in Fig. 4(d), Fig. 7 (a ₃ , a ₄ , b ₃ , b ₄ ), and Fig. 8(b).

Example 9: The preparation steps are as follows, 1), 0.006 moles of aluminum nitrate Al(NO ₃ ) ₃ ·9H ₂ O, 0.009 moles of strontium nitrate Sr(NO ₃ ) ₂ , 0.00002 moles of europium nitrate Eu(NO ₃ ) ₃ , 0.00003 One mole of dysprosium nitrate Dy(NO ₃ ) ₃ , 0.02 mole of urea CO(NH ₂ ) ₂ , 0.03 mole of sodium citrate C ₆ H ₅ Na ₃ O ₇ ·2H ₂ O were placed in a beaker, and 40-50 ml of Distill water, stir to dissolve, put the above solution in a closed reaction kettle, and keep it warm at 120-200°C for 10-14 hours to obtain a white product. 2) Filter and wash the cooled white product with distilled water and ethanol, and dry it at 50-70°C for 5-6 hours to obtain the precursor shown in Figure 5(b). 3) Anneal the precursor in an air atmosphere at 1200°C for 2 to 4 hours to prepare strontium aluminate as shown in Figure 1(d), Figure 5(c), and Figure 6(a ₁ , b ₁ ) Luminescent material.

Example 10: The preparation steps are as follows, 1), 0.006 moles of aluminum nitrate Al(NO ₃ ) ₃ ·9H ₂ O, 0.009 moles of strontium nitrate Sr(NO ₃ ) ₂ , 0.00002 moles of europium nitrate Eu(NO ₃ ) ₃ , 0.00003 One mole of dysprosium nitrate Dy(NO ₃ ) ₃ , 0.02 mole of urea CO(NH ₂ ) ₂ , 0.03 mole of sodium citrate C ₆ H ₅ Na ₃ O ₇ ·2H ₂ O were placed in a beaker, and 40-50 ml of Distill water, stir to dissolve, put the above solution in a closed reaction kettle, and keep it warm at 120-200°C for 10-14 hours to obtain a white product. 2) The cooled white product is filtered and washed with distilled water and ethanol, and dried at 50-70° C. for 5-6 hours to obtain a precursor. 3), annealing the precursor in a reducing atmosphere at 1200° C. for 2 to 4 hours; wherein, the reducing gas is a mixture of 5-20% hydrogen and 80-95% argon, as shown in Figure 2 ( d), the strontium aluminate luminescent material shown in Fig. 5(d), Fig. 7 (a ₁ , a ₂ , b ₁ , b ₂ ), and Fig. 8(a).

Claims (6)

1. A nano-strontium aluminate luminescent material, characterized in that: The chemical formula of the luminescent material is: Sr _3-xy Al ₂ O ₆ : x Eu ²⁺ (Eu ³⁺ ), y Dy ³⁺ (0<x≤0.02, 0<y≤0.04); wherein, Sr is strontium , Al is aluminum, O is oxygen, Eu ²⁺ (Eu ³⁺ ) is europium ions, Dy ³⁺ is dysprosium ions, that is, the luminescent material is strontium aluminate co-doped with europium and dysprosium ions. 2. The controllable synthesis method of nano-strontium aluminate luminescent material as claimed in claim 1, which is characterized in that it is a two-step method of hydrothermal synthesis-calcination, and is operated according to the following steps and feeding ratio: (1) Weigh 0.005 to 0.007 moles of aluminum nitrate, 0.008 to 0.0095 moles of strontium nitrate, 0.000015 to 0.000025 moles of europium nitrate, 0.000025 to 0.000035 moles of dysprosium nitrate, and 0.015 to 0.025 moles of urea in a reaction vessel, and then add 40 to 50 ml of distilled water, stirred and dissolved, put the above solution in a closed reaction kettle, and kept it at 120°C-200°C for 10-14 hours to obtain a white product; (2) filter and wash the cooled white product with distilled water and ethanol respectively, and dry at 50-70° C. for 5-6 hours to obtain the precursor; (3) annealing the precursor in an air atmosphere or a reducing atmosphere at 900-1200° C. for 2-4 hours to prepare a strontium aluminate luminescent material. 3. The controllable synthesis method of nano-strontium aluminate luminescent material as claimed in claim 2, characterized in that it operates according to the following steps and feeding ratio: (1) Weigh 0.006 moles of aluminum nitrate, 0.009 moles of strontium nitrate, 0.00002 moles of europium nitrate, 0.00003 moles of dysprosium nitrate, and 0.02 moles of urea in a reaction vessel, then add 40 to 50 milliliters of distilled water to it, stir to dissolve, and dissolve the above solution Put it in a closed reaction kettle and keep it warm at 120°C-200°C for 10-14 hours to obtain a white product; (2) filter and wash the cooled white product with distilled water and ethanol, and dry it at 50-70° C. for 5-6 hours to obtain the precursor; (3) annealing the precursor in an air atmosphere or a reducing atmosphere at 900-1200° C. for 2-4 hours to prepare a strontium aluminate luminescent material. 4. The controllable synthesis method of nano-strontium aluminate luminescent material as claimed in claim 2 or 3, characterized in that 0.03 mole of sodium citrate is added in step (1) to control the shape of strontium aluminate to be spherical. 5. the controllable synthesis method of nanometer strontium aluminate luminescent material as claimed in claim 2 or 3, it is characterized in that described aluminum nitrate, strontium nitrate, europium nitrate, dysprosium nitrate, urea, sodium citrate select Al for use respectively ( NO ₃ ) ₃ ·9H ₂ O, Sr(NO ₃ ) ₂ , Eu(NO ₃ ) ₃ , Dy(NO ₃ ) ₃ , CO(NH ₂ ) ₂ , C ₆ H ₅ Na ₃ O ₇ ·2H ₂ O. 6. The controllable synthesis method of nano-strontium aluminate luminescent material according to claim 2 or 3, characterized in that the reducing atmosphere is a mixed gas composed of 5-20% hydrogen and 80-95% argon.

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