CN105087006A - Samarium and europium-codoped yttrium barium phosphate fluorescent powder and preparation method thereof - Google Patents

Abstract

A samarium-europium co-doped yttrium barium phosphate fluorescent powder and its preparation method, the chemical formula of the fluorescent powder is: Ba ₃ Y _{( 1-xy )} Sm _x Eu _y ? (PO ₄ ) ₃ , where x is 0.001-0.2, and y is 0.001-0.2. The invention obtains a red fluorescent powder by substituting Sm ³⁺ and Eu ³⁺ for Y ³⁺ , which has high crystallization degree, high luminous intensity and good color rendering. Phosphor powder can be effectively excited by purple light or ultraviolet light, and emits red fluorescence mainly at 598nm and 610nm wavelengths. It is a red phosphor powder that can be used for white LEDs or energy-saving lamps. The invention has simple operation, low production cost and equipment requirements, stable product quality and easy industrial production.

Description

A kind of samarium europium co-doped yttrium barium phosphate fluorescent powder and preparation method thereof

technical field

The invention relates to the field of ultraviolet-violet white light LED lighting and display phosphors, in particular to a samarium-europium co-doped yttrium barium phosphate phosphor and a preparation method thereof.

Background technique

White light-emitting diode (LED) is called the fourth generation of lighting source. As a new generation of solid light source, in addition to overcoming the shortcomings of traditional incandescent and fluorescent lamps such as high energy consumption, fragility, and pollution, it also has small size and environmental protection. , fast response, long life, planar packaging, high luminous intensity, high efficiency, energy saving, vibration resistance, low voltage drive, and no environmental pollution. Especially in recent years, with the rapid development of blue, purple and ultraviolet LEDs, white LEDs have great application prospects in the field of lighting, and are recognized as green lighting sources that replace fluorescent lamps and incandescent lamps.

There are three main ways to realize white LED: one is to combine red, green and blue LEDs to produce white light. However, the circuit design of this method is complicated and the cost is high. The second is to use quantum effects to realize single-chip white light, but the cost is high and the technology is not yet mature. The third is to use blue light, purple light or ultraviolet light LEDs to excite the various colors of light emitted by different color phosphors to cooperate with each other to achieve white light. This method is simple and easy, and the cost is low. In 1996, it was first reported to use blue LEDs with YAG:Dy ³⁺ yellow emitting phosphors to realize white LEDs. In the subsequent development, the luminous efficiency has exceeded 100lm/W. However, the emission intensity of YAG phosphor in the red light region is very weak, resulting in the lack of red light after being mixed with blue LED chips, which affects the correlated color temperature and color rendering index of white LEDs. These deficiencies in phosphor powder have become a bottleneck for improving the development of white light LEDs. The performance of phosphor powder determines the technical indicators such as luminous efficiency, color temperature, and color rendering index of white light LEDs. Phosphor powder has become a hot spot and an urgent task in current research.

In addition, the luminous efficiency of the fluorescent material is not only related to its chemical composition and structure, but different preparation methods lead to different properties of the fluorescent material, which will have a significant impact on the luminous performance of the fluorescent material. For example, fluorescent materials in phosphate systems are often synthesized by high-temperature solid-phase synthesis, which requires high reaction temperature, long preparation time, and high requirements for experimental equipment. Because the reaction at high temperature is prone to agglomeration, the obtained product has a large particle size. , requires ball milling, which will seriously affect the luminous brightness and performance of fluorescent materials. However, the sol-gel preparation process is difficult to realize for phosphate fluorescent materials. Therefore, selecting a suitable method for preparing fluorescent materials is also an urgent problem in this technical field.

Contents of the invention

In order to solve the shortcomings of the existing YAG:Dy ³⁺ yellow emitting phosphor powder to achieve white light technology, the red component is insufficient, the color rendering index and color temperature are insufficient, and the high-temperature solid-phase method is easy to agglomerate, and the luminous efficiency is easily affected after the particles are broken by ball milling. The present invention provides a A samarium-europium co-doped yttrium barium phosphate fluorescent powder and a preparation method thereof, the fluorescent powder is excited by ultraviolet light or near ultraviolet light, has high luminous efficiency, and the preparation method is simple and environmentally friendly.

The technical solution adopted by the present invention to solve the above technical problems is: a samarium-europium co-doped yttrium barium phosphate phosphor, the chemical formula of which phosphor is: Ba ₃ Y _(1-xy) Sm _x Eu _y (PO ₄ ) ₃ , where x takes 0.001~0.2, y takes 0.001~0.2.

The preparation method of the above-mentioned samarium-europium co-doped yttrium barium phosphate fluorescent powder comprises the following steps:

1) Weigh the barium source, yttrium source, samarium source, europium source and phosphorus source according to the above stoichiometric ratio, and completely dissolve the phosphorus source with deionized water to prepare a phosphorus source solution, and in the phosphorus source solution, phosphoric acid The concentration of root or equivalent phosphate is 0.05mol/l to saturation concentration, for later use;

Saturation concentration refers to the maximum solubility of phosphorus source dissolved in deionized water at room temperature;

2) Take fuming nitric acid, add deionized water to it to adjust its concentration to 15-20mol/l, and prepare a reaction system for future use;

Wherein, the amount of nitric acid should ensure that it can completely dissolve the barium source, yttrium source, samarium source and europium source in step 1);

3) Add the weighed barium source in step 1) to the reaction system prepared in step 2), add the weighed yttrium source in step 1) after it is completely dissolved, and then add the weighed yttrium source in step 1) after the yttrium source is completely dissolved The weighed samarium source, after the samarium source is completely dissolved, then add the weighed europium source in step 1), and finally add ammonia water dropwise to adjust the pH value to 1~2. During this process, keep the reaction system by heating while stirring The temperature of the solution is kept at 85-90°C, and a transparent and clear solution is finally obtained, which is ready for use;

4) Add the phosphorus source solution prepared in step 1) to the transparent and clear solution obtained in step 3), stir well and add ammonia water dropwise to cause precipitation reaction, keep the temperature of the reaction system at 85-90°C, and pH ≥ 8.0 , and keep stirring until the amount of precipitation no longer increases, then filter to obtain a white precipitate, dry the white precipitate to obtain a reaction precursor, and set aside;

5) Heat the reaction precursor obtained in step 4) to 1000-1350°C at a heating rate of 4-15°C/min in an air atmosphere, sinter at this temperature for 2-8 hours, and grind it into powder after natural cooling. And ultrasonic cleaning with deionized water, the product can be obtained after drying.

The barium source is one or more mixtures of barium carbonate, barium nitrate, barium sulfate and barium chloride.

The yttrium source is one or more mixtures of yttrium oxide, yttrium carbonate, and yttrium nitrate.

The samarium source is one or more mixtures of samarium oxide, samarium nitrate and samarium chloride.

The europium source is one or more mixtures of europium oxide, europium nitrate and europium chloride.

The phosphorus source is one or more mixtures of diammonium hydrogen phosphate, ammonium dihydrogen phosphate and ammonium phosphate.

Beneficial effect: compared with the prior art, the present invention has the following advantages:

1) The yttrium barium phosphate red phosphor co-doped with samarium ions and europium ions prepared by the present invention can be effectively excited by purple light or ultraviolet light, and the main excitation light is 360±1nm, 374±1nm, 393±1nm, 402±1nm, 462±1nm;

2) The yttrium barium phosphate red phosphor powder co-doped with samarium ions and europium ions prepared by the present invention emits red light with main peak wavelengths of 598nm and 610nm, high luminous efficiency, high luminous intensity, and pure chromaticity;

3) The present invention uses the solution preparation method to mix the reaction in the ionic state, precisely control the stoichiometry and control the temperature and pH value of the reaction system, so that it can be synthesized at a lower sintering temperature and obtain crystallization properties Good red phosphor with higher emission intensity, loose structure, fine particles, uniform distribution, and good coating performance;

4) The yttrium barium phosphate red fluorescent powder co-doped with samarium ions and europium ions prepared by the present invention has rich sources of raw materials, low price, simple preparation process, easy operation, low requirements for equipment, stable finished product quality and good process repeatability , suitable for large-scale production;

5) The yttrium barium phosphate red phosphor co-doped with samarium ions and europium ions prepared by the present invention has good thermal stability. Compared with other sulfides, halides, and borates, it is resistant to high temperature, humidity, and environmentally friendly.

Description of drawings

Fig. 1 is the X-ray powder diffraction pattern of the sample that embodiment 3 makes;

Fig. 2 is the absorption spectrogram of the sample that embodiment 3 makes;

Fig. 3 is a luminescence spectrum diagram of the sample prepared in Example 3 under excitation at a wavelength of 374nm.

Detailed ways

Below in conjunction with specific embodiment, the present invention is further elaborated, the barium source used in each embodiment of the present invention is one or more mixes in barium carbonate, barium nitrate, barium sulfate, barium chloride, and yttrium source is yttrium oxide, One or more mixtures of yttrium carbonate and yttrium nitrate, samarium source is one or more mixtures of samarium oxide, samarium nitrate, and samarium chloride, and europium source is one of europium oxide, europium nitrate, and europium chloride or multiple mixtures, and the phosphorus source is one or more mixtures of diammonium hydrogen phosphate, ammonium dihydrogen phosphate, and ammonium phosphate.

Example 1

A yttrium barium phosphate fluorescent powder co-doped with samarium and europium, the chemical formula of the fluorescent powder is: Ba ₃ Y _0.799 Sm _0.2 Eu _0.001 (PO ₄ ) ₃ .

The preparation method of the above-mentioned samarium-europium co-doped yttrium barium phosphate fluorescent powder comprises the following steps:

1) Weigh the barium source, yttrium source, samarium source, europium source and phosphorus source according to the above stoichiometric ratio, and completely dissolve the phosphorus source with deionized water to prepare a phosphorus source solution, and in the phosphorus source solution, phosphoric acid Root or equivalent phosphate concentration is 0.05mol/l, reserve;

2) Take fuming nitric acid, add deionized water to it to adjust its concentration to 15mol/l, and prepare a reaction system for future use;

Wherein, the amount of nitric acid should ensure that it can completely dissolve the barium source, yttrium source, samarium source and europium source in step 1);

3) Add the weighed barium source in step 1) to the reaction system prepared in step 2), add the weighed yttrium source in step 1) after it is completely dissolved, and then add the weighed yttrium source in step 1) after the yttrium source is completely dissolved The weighed samarium source, after the samarium source is completely dissolved, then add the weighed europium source in step 1), and finally add ammonia water to adjust the pH value to 1. During this process, heat while stirring Keep the temperature of the reaction system at 85-90°C, and finally obtain a transparent and clear solution for later use;

4) Add the phosphorus source solution prepared in step 1) to the transparent and clear solution obtained in step 3), stir well and add ammonia water dropwise to cause precipitation reaction, keep the temperature of the reaction system at 85-90°C, and the pH at 8.0 , and keep stirring until the amount of precipitation no longer increases, then filter to obtain a white precipitate, dry the white precipitate to obtain a reaction precursor, and set aside;

5) Heat the reaction precursor obtained in step 4) to 1000°C at a heating rate of 4°C/min in an air atmosphere, and sinter at this temperature for 8 hours. After natural cooling, grind it into powder, and clean it with deionized water ultrasonically. , the product is obtained after drying.

Example 2

A yttrium barium phosphate fluorescent powder co-doped with samarium and europium, the chemical formula of the fluorescent powder is: Ba ₃ Y _0.799 Sm _0.001 Eu _0.2 (PO ₄ ) ₃ .

The preparation method of the above-mentioned samarium-europium co-doped yttrium barium phosphate fluorescent powder comprises the following steps:

1) Weigh the barium source, yttrium source, samarium source, europium source and phosphorus source according to the above stoichiometric ratio, and completely dissolve the phosphorus source with deionized water to prepare a phosphorus source solution (phosphate or equivalent phosphate concentration 0.05mol/l～saturation), spare;

2) Take fuming nitric acid, add deionized water to it to adjust its concentration to 20mol/l, and prepare a reaction system for future use;

Wherein, the amount of nitric acid should ensure that it can completely dissolve the barium source, yttrium source, samarium source and europium source in step 1);

3) Add the weighed barium source in step 1) to the reaction system prepared in step 2), add the weighed yttrium source in step 1) after it is completely dissolved, and then add the weighed yttrium source in step 1) after the yttrium source is completely dissolved The weighed samarium source, after the samarium source is completely dissolved, then add the weighed europium source in step 1), and finally add ammonia water to adjust the pH value to 2.0. During this process, heat while stirring Keep the temperature of the reaction system at 85-90°C, and finally obtain a transparent and clear solution for later use;

4) Add the phosphorus source solution prepared in step 1) to the transparent and clear solution obtained in step 3), stir well and add ammonia water dropwise to cause precipitation reaction, keep the temperature of the reaction system at 85-90°C, and pH at 9.0 , and keep stirring until the amount of precipitation no longer increases, then filter to obtain a white precipitate, dry the white precipitate to obtain a reaction precursor, and set aside;

5) Heat the reaction precursor obtained in step 4) to 1350°C at a heating rate of 15°C/min in an air atmosphere, and sinter at this temperature 2, and grind it into powder after natural cooling, and ultrasonically clean it with deionized water , the product is obtained after drying.

Example 3

A yttrium barium phosphate fluorescent powder co-doped with samarium and europium, the chemical formula of the fluorescent powder is: Ba ₃ Y _0.88 Sm _0.06 Eu _0.06 (PO ₄ ) ₃ .

The preparation method of the above-mentioned samarium-europium co-doped yttrium barium phosphate fluorescent powder comprises the following steps:

1) Weigh the barium source, yttrium source, samarium source, europium source and phosphorus source according to the stoichiometric ratio described in claim 1, and completely dissolve the phosphorus source with deionized water to prepare a phosphorus source solution (phosphate or other The effective phosphate concentration is 0.05mol/l~saturation), for standby;

2) Take fuming nitric acid, add deionized water to it to adjust its concentration to 18mol/l, and prepare a reaction system for future use;

Wherein, the amount of nitric acid should ensure that it can completely dissolve the barium source, yttrium source, samarium source and europium source in step 1);

3) Add the weighed barium source in step 1) to the reaction system prepared in step 2), add the weighed yttrium source in step 1) after it is completely dissolved, and then add the weighed yttrium source in step 1) after the yttrium source is completely dissolved The weighed samarium source, after the samarium source is completely dissolved, then add the weighed europium source in step 1), and finally add ammonia water to adjust the pH value to 1. During this process, heat while stirring Keep the temperature of the reaction system at 85-90°C, and finally obtain a transparent and clear solution for later use;

4) Add the phosphorus source solution prepared in step 1) to the transparent and clear solution obtained in step 3), stir well and add ammonia water dropwise to cause precipitation reaction, keep the temperature of the reaction system at 85-90°C, and the pH at 11.0 , and keep stirring until the amount of precipitation no longer increases, then filter to obtain a white precipitate, dry the white precipitate to obtain a reaction precursor, and set aside;

5) Heat the reaction precursor obtained in step 4) to 1200°C at a heating rate of 10°C/min in an air atmosphere, and sinter at this temperature for 6 hours. After natural cooling, grind it into powder, and clean it with deionized water ultrasonically , the product is obtained after drying.

Example 4

A yttrium barium phosphate fluorescent powder co-doped with samarium and europium, the chemical formula of the fluorescent powder is: Ba ₃ Y _0.8 Sm _0.1 Eu _0.1 (PO ₄ ) ₃ .

The preparation method of the above-mentioned samarium-europium co-doped yttrium barium phosphate fluorescent powder comprises the following steps:

1) Weigh the barium source, yttrium source, samarium source, europium source and phosphorus source according to the stoichiometric ratio described in claim 1, and completely dissolve the phosphorus source with deionized water to prepare a phosphorus source solution (phosphate or other The effective phosphate concentration is 0.05mol/l~saturation), for standby;

2) Take fuming nitric acid, add deionized water to it to adjust its concentration to 19mol/l, and prepare a reaction system for future use;

Wherein, the amount of nitric acid should ensure that it can completely dissolve the barium source, yttrium source, samarium source and europium source in step 1);

3) Add the weighed barium source in step 1) to the reaction system prepared in step 2), add the weighed yttrium source in step 1) after it is completely dissolved, and then add the weighed yttrium source in step 1) after the yttrium source is completely dissolved The weighed samarium source, after the samarium source is completely dissolved, then add the weighed europium source in step 1), and finally add ammonia water to adjust the pH value to 2. During this process, heat while stirring Keep the temperature of the reaction system at 85-90°C, and finally obtain a transparent and clear solution for later use;

4) Add the phosphorus source solution prepared in step 1) to the transparent and clear solution obtained in step 3), stir well and add ammonia water dropwise to cause precipitation reaction, keep the temperature of the reaction system at 85-90°C, and the pH at 12.0 , and keep stirring until the amount of precipitation no longer increases, then filter to obtain a white precipitate, dry the white precipitate to obtain a reaction precursor, and set aside;

5) Heat the reaction precursor obtained in step 4) to 1300°C at a heating rate of 9°C/min in an air atmosphere, and sinter at this temperature for 4 hours. After natural cooling, grind it into powder, and clean it with deionized water ultrasonically. , the product is obtained after drying.

Claims (7)

1. A barium yttrium phosphate phosphor doped with samarium and europium, characterized in that: the chemical formula of the phosphor is: Ba ₃ Y _(1-xy) Sm _x Eu _y (PO ₄ ) ₃ , where x is 0.001 to 0.2, y takes 0.001 to 0.2. 2. the preparation method of the yttrium barium phosphate fluorescent powder of a kind of samarium europium co-doped according to claim 1, is characterized in that, comprises the following steps: 1) Weigh the barium source, yttrium source, samarium source, europium source and phosphorus source according to the stoichiometric ratio described in claim 1, and completely dissolve the phosphorus source with deionized water to prepare a phosphorus source solution. In the solution, the concentration of phosphate or equivalent phosphate is 0.05mol/l to saturation concentration, and it is ready for use; 2) Take fuming nitric acid, add deionized water to it to adjust its concentration to 15-20mol/l, and prepare a reaction system for future use; Wherein, the amount of nitric acid should ensure that it can completely dissolve the barium source, yttrium source, samarium source and europium source in step 1); 3) Add the weighed barium source in step 1) to the reaction system prepared in step 2), add the weighed yttrium source in step 1) after it is completely dissolved, and then add the weighed yttrium source in step 1) after the yttrium source is completely dissolved The weighed samarium source, after the samarium source is completely dissolved, then add the weighed europium source in step 1), and finally add ammonia water dropwise to adjust the pH value to 1~2. During this process, keep the reaction system by heating while stirring The temperature of the solution is kept at 85-90°C, and a transparent and clear solution is finally obtained, which is ready for use; 4) Add the phosphorus source solution prepared in step 1) to the transparent and clear solution obtained in step 3), stir well and add ammonia water dropwise to cause precipitation reaction, keep the temperature of the reaction system at 85-90°C, and pH ≥ 8.0 , and keep stirring until the amount of precipitation no longer increases, then filter to obtain a white precipitate, dry the white precipitate to obtain a reaction precursor, and set aside; 5) Heat the reaction precursor obtained in step 4) to 1000-1350°C at a heating rate of 4-15°C/min in an air atmosphere, sinter at this temperature for 2-8 hours, and grind it into powder after natural cooling. And ultrasonic cleaning with deionized water, the product can be obtained after drying. 3. the preparation method of the yttrium barium phosphate fluorescent powder of a kind of samarium europium co-doped according to claim 2 is characterized in that: described barium source is barium carbonate, barium nitrate, barium sulfate, barium chloride One or more mixed. 4. the preparation method of the yttrium barium phosphate fluorescent powder of a kind of samarium europium co-doped according to claim 2 is characterized in that: described yttrium source is one or more in yttrium oxide, yttrium carbonate, yttrium nitrate kind of mix. 5. the preparation method of a kind of samarium-europium co-doped yttrium barium phosphate phosphor according to claim 2 is characterized in that: described samarium source is one or more of samarium oxide, samarium nitrate, samarium chloride kind of mix. 6. the preparation method of the yttrium barium phosphate fluorescent powder of a kind of samarium europium co-doped according to claim 2 is characterized in that: described europium source is a kind of in europium oxide, europium nitrate, europium chloride or Various mixes. 7. the preparation method of the yttrium barium phosphate fluorescent powder of a kind of samarium europium co-doped according to claim 2 is characterized in that: described phosphorus source is diammonium hydrogen phosphate, ammonium dihydrogen phosphate, ammonium phosphate One or more mixed.