Beta-sialon (Si)5AlON7) Cyan luminescent phosphor and synthetic method and application thereof
阅读说明：本技术 一种β-塞隆(Si5AlON7)青色发光荧光粉及其合成方法和应用 (Beta-sialon (Si)5AlON7) Cyan luminescent phosphor and synthetic method and application thereof ) 是由 葛万银 陆晨辉 徐美美 张盼锋 张伟 于 2021-08-30 设计创作，主要内容包括：本发明公开了一种β-塞隆(Si-(5)AlON-(7))青色发光荧光粉及其合成方法和应用,将废弃的晶硅碎料进行研磨,过筛,形成粉状,然后按比例称取Si粉、Al(OH)-(3)及铕源,并充分混合研磨,将研磨好的混合物粉末放入管式炉中,向管式炉内通入惰性气体,以一定的升温速率加热到指定温度,并保温一段时间,保温结束后,冷却到室温经过研磨即得所述塞隆青色发光荧光粉(SiAlON:Eu)。所涉及到的荧光粉材料合成工艺简单,化学稳定性好,热淬灭低,发光强度高,可满足大功率LED用荧光粉的要求和工业化生产的需求。(The invention discloses a beta-sialon (Si) 5 AlON 7 ) A cyan fluorescent powder is prepared from waste crushed crystalline silicon through grinding, sieving to obtain powder, proportionally mixing Si powder with Al (OH) 3 And a europium source, fully mixing and grinding, putting the ground mixture powder into a tube furnace, introducing inert gas into the tube furnace, heating to a specified temperature at a certain heating rate, preserving heat for a period of time, cooling to room temperature after the heat preservation is finished, and grinding to obtain the SiAlON cyan luminescent phosphor (SiAlON: Eu). The fluorescent powder material has simple synthesis process, good chemical stability, low thermal quenching and high luminous intensity, and can meet the requirements of fluorescent powder for high-power LEDs and the requirements of industrial production.)
1. Beta-sialon (Si)5AlON7) The synthesis method of the cyan luminescent phosphor is characterized in that waste crystalline silicon crushed aggregates are ground and sieved to obtain silicon powder; mixing silicon powder and Al (OH)3Mixing with Eu source and grinding to obtain mixtureCompound powder; heating the ground mixture powder to 1350-1500 ℃ in inert gas; then carrying out heat preservation treatment, cooling to room temperature after the heat preservation is finished, and grinding to obtain beta-sialon (Si)5AlON7) A cyan emitting phosphor.
2. The method according to claim 1, wherein the silicon powder is obtained by sieving with a 50-300 mesh sieve.
3. The process of claim 1, wherein the ratio of silicon powder: al (OH)3: the mass ratio of the europium source is 1 (0.3-2.4) to 0.2-1.
4. The method of claim 3, wherein the Eu source is europium nitrate or europium acetate.
5. The method according to claim 1, wherein the inert gas is a high purity nitrogen gas, and the flow rate of the high purity nitrogen gas is 40 to 300 sccm.
6. The method of claim 1, wherein the ground mixture powder is heated to 1000 ℃ at a rate of 10 ℃/min, heated to 1300 ℃ at a rate of 4 ℃/min, and heated to 1350-1500 ℃ at a rate of 2 ℃/min.
7. The method according to claim 1, wherein the holding time is 3 to 5 hours.
8. Beta-sialon (Si)5AlON7) A cyan-emitting phosphor prepared by the method according to any one of claims 1 to 7.
9. Beta-sialon (Si) according to claim 85AlON7) A cyan-emitting phosphor characterized in that beta-sialon (Si)5AlON7) The cyan luminescent phosphor has brightness under the excitation of 365nm ultraviolet lampThe blue light emitting performance of the LED can obtain a white LED light source through blue light excitation.
10. Beta-sialon (Si) prepared according to the process of any one of claims 1 to 75AlON7) Cyan emitting phosphor or beta-sialon (Si) according to claim 8 or 95AlON7) The cyan light-emitting fluorescent powder is applied to a white LED light source.
Technical Field
The invention belongs to the technical field of preparation of inorganic fluorescent materials, and particularly relates to beta-sialon (Si)5AlON7) Cyan luminescent phosphor and a synthesis method and application thereof.
Background
Since the LED has excellent properties such as high brightness, high color rendering index, energy saving, long life, very small size, and flexible color conversion, the LED has been continuously applied and improved by people since the 90 th generation of light emitting diodes in the last century, and has rapidly replaced the conventional illumination mode, thus becoming the fourth generation of illumination light source.
Since silicon-based nitride phosphors were successfully synthesized in the laboratory for the first time, the search for research on phosphors such as sulfide and YAG-based phosphors in the illumination field was open to mankind. The discovery of silicon-based nitride phosphors has revolutionized the development of LEDs. Silicon-based nitride phosphors, particularly SiAlON (SiAlON) phosphors, are one of the best quality phosphors for LEDs, and have been extensively and intensively studied in various countries. And the patents on the sialon fluorescent powder are the trend that each country occupies the highest market. From the perspective of crystal structure, sialon phosphors pass through Al3+And O2By introducing into the substrate Si3N4Si in the crystal4+And N3-Thereby changing the coordination environment doped into the substrate unit cell, leading to crystal field splitting of different degrees, and realizing the luminescence of different color bands. As is well known, SiAlON is mainly classified into alpha-SiAlON and beta-SiAlON, and in recent years, main research work has been mainly focused on beta-SiAlON, the general formula of which is Si6-zAlzOzN8-zWherein z is more than 0 and less than or equal to 4.2.
The existing method for synthesizing the beta-SiAlON fluorescent powder mainly comprises three methods, namely a carbothermic method, a gas reduction nitridation method and a high-temperature solid phase method, wherein the three processes are relatively complicated and need to be carried out through multiple steps or mixing of multiple raw materials. In the existing scheme, a precursor is obtained by a sol-gel method, the pH of the raw material is regulated, and high-temperature reaction is further carried out after pretreatment. At present, after high-temperature heat treatment, negative pressure sintering is required to be carried out continuously to obtain a final product, and vacuum equipment is introduced to control negative pressure. And the synthesis conditions required for some synthesis methods are too high, requiring ultra-high temperatures in excess of 2000 ℃. The existing synthesis temperature is as high as 2200 ℃ and the like, which greatly increases the energy consumption required by synthesis and increases the synthesisDifficulty. Due to the introduction of carbon atoms, the existence of carbon after the reaction of the carbothermic method has a great negative influence on the luminescent quality of the sialon fluorescent powder. High temperature solid phase method uses high purity Si3N4Si of high purity as one of the basic raw materials3N4The price of (a) is very expensive, which results in a high price of β -SiAlON. In addition, break up Si3N4Chemical bonds, require high reaction temperatures. Therefore, the traditional high-temperature solid phase method is very energy-consuming. The gas reduction nitridation method needs ammonia with strong irritation, and a treatment process of ammonia tail gas is also added in the actual production process, so that the preparation process becomes very complicated.
Disclosure of Invention
Based on the beta-SiAlON fluorescent powder for the existing LED and a plurality of defects in synthesis, the method for preparing the beta-SiAlON (Si) by a one-step method is provided5AlON7) The synthesis method of the cyan luminescent phosphor changes waste into valuable, the temperature required by synthesis is lower, the reaction time is shorter, and the waste silicon crystal scraps are reused to obtain the beta-SiAlON cyan luminescent phosphor with excellent thermal stability and high brightness.
The invention adopts the following technical scheme:
beta-sialon (Si)5AlON7) The synthesis method of the cyan luminescent phosphor comprises the steps of grinding waste crystalline silicon crushed aggregates and then sieving the crushed aggregates to obtain silicon powder; mixing silicon powder and Al (OH)3Mixing with a Eu source and grinding to obtain mixture powder; heating the ground mixture powder to 1350-1500 ℃ in inert gas; then carrying out heat preservation treatment, cooling to room temperature after the heat preservation is finished, and grinding to obtain beta-sialon (Si)5AlON7) A cyan emitting phosphor.
Specifically, the silicon powder is obtained by sieving with a 50-300-mesh sieve.
Specifically, silicon powder: al (OH)3: the mass ratio of the europium source is 1 (0.3-2.4) to 0.2-1.
Further, the Eu source is europium nitrate or europium acetate.
Specifically, the inert gas is high-purity nitrogen, and the flow rate of the high-purity nitrogen is 40-300 sccm.
Specifically, the ground mixture powder is heated to 1000 ℃ at the speed of 10 ℃/min, then heated to 1300 ℃ at the speed of 4 ℃/min, and finally heated to 1350-1500 ℃ at the speed of 2 ℃/min.
Specifically, the heat preservation time is 3-5 h.
The other technical scheme of the invention is that the beta-sialon (Si)5AlON7) A cyan emitting phosphor.
In particular, beta-sialon (Si)5AlON7) The cyan luminescent phosphor has bright cyan luminescent property under the excitation of a 365nm ultraviolet lamp, and a white LED light source can be obtained through blue light excitation.
Another technical scheme of the invention is that beta-sialon (Si)5AlON7) The cyan light-emitting fluorescent powder is applied to a white LED light source.
Compared with the prior art, the invention has at least the following beneficial effects:
the invention relates to beta-sialon (Si)5AlON7) The synthesis method of cyan luminescent phosphor adopts a constant-temperature solid phase method and comprises the steps of mixing silicon powder, Al (OH)3Fully mixing and grinding the europium source; heating the ground powder to a specified temperature, preserving the temperature, controlling the reaction temperature to 1350-1500 ℃, and cooling to room temperature after the reaction is finished to synthesize the high-purity beta-SiAlON (Si)5AlON7) The cyan luminescent phosphor (SiAlON: Eu) has the advantages of simple raw materials, easy operation of the synthesis method, short heat preservation time and lower production cost, and is very suitable for large-scale industrial production.
Further, the waste crystalline silicon crushed aggregates are ground and sieved to form powder, so that waste is changed into valuable, the environmental cost for treating the waste crystalline silicon crushed aggregates is saved, and a silicon source is introduced; using Al (OH)3For the purpose of introducing a substitution for Si4+And N3-Al of (2)3+And O2-(ii) a The europium sources used comprise europium nitrate and europium acetate, and the price of the conventional reagents for both the europium sources is low.
Furthermore, the chemical composition ratio of the beta-SiAlON can be strictly controlled by controlling the chemical composition ratio of the raw materials.
Further, europium atoms are effectively doped into the matrix during the high-temperature heating process. In addition, considering practical application, other europium sources have higher prices, which substantially increases the cost of the product.
Furthermore, high-purity nitrogen is introduced, air in the hearth does not need to be pumped out, the step and the cost of vacuumizing can be saved, a certain amount of oxygen can be ensured in the reaction atmosphere in the hearth, and the introduced nitrogen can become an N source in the high-temperature reaction.
Furthermore, the growth rate of the silicon nitride crystal nucleus can be controlled through three times of temperature rise treatment, and meanwhile, the annealing furnace is not too high in temperature rise rate, so that the purpose of protecting the annealing furnace to a certain extent is achieved.
Further, the europium atoms are given a sufficiently high energy at high temperatures so that they penetrate into the matrix of the silicon nitride.
In conclusion, the method is simple and easy to implement, has good repeatability and can meet the requirement of batch production.
The technical solution of the present invention is further described in detail by the accompanying drawings and embodiments.
Drawings
FIG. 1 is a scheme of synthesis of beta-SiAlON (Si) according to example 1 of the present invention5AlON7) Scanning Electron Microscopy (SEM) images of nanomaterials;
FIG. 2 shows the synthesis of beta-SiAlON (Si) in example 2 of the present invention5AlON7) The photoluminescence spectrum of the nanomaterial of (a);
FIG. 3 is a schematic representation of the synthesis of beta-SiAlON (Si) according to example 3 of the present invention5AlON7) The X-ray diffraction spectrum of the nanomaterial of (a);
FIG. 4 shows the synthesis of beta-SiAlON (Si) in example 4 of the present invention5AlON7) The X-ray diffraction spectrum of the nanomaterial of (a);
FIG. 5 shows the synthesis of beta-SiAlON (Si) in example 5 of the present invention5AlON7) The X-ray diffraction spectrum of the nanomaterial of (1).
Detailed Description
The technical solutions of the present invention will be described clearly and completely below, and it should be apparent that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In the present invention, all the embodiments and preferred methods mentioned herein can be combined with each other to form a new technical solution, if not specifically stated.
In the present invention, all the technical features mentioned herein and preferred features may be combined with each other to form a new technical solution, if not specifically stated.
In the present invention, the percentage (%) or parts means the weight percentage or parts by weight with respect to the composition, if not otherwise specified.
In the present invention, the components referred to or the preferred components thereof may be combined with each other to form a novel embodiment, if not specifically stated.
In the present invention, unless otherwise stated, the numerical range "a-b" represents a shorthand representation of any combination of real numbers between a and b, where a and b are both real numbers. For example, a numerical range of "6 to 22" means that all real numbers between "6 to 22" have been listed herein, and "6 to 22" is simply a shorthand representation of the combination of these values.
The "ranges" disclosed herein may have one or more lower limits and one or more upper limits, respectively, in the form of lower limits and upper limits.
As used herein, the term "and/or" refers to any and all possible combinations of one or more of the associated listed items and includes such combinations.
In the present invention, unless otherwise specified, the individual reactions or operation steps may be performed sequentially or may be performed in sequence. Preferably, the reaction processes herein are carried out sequentially.
Unless otherwise defined, technical and scientific terms used herein have the same meaning as is familiar to those skilled in the art. In addition, any methods or materials similar or equivalent to those described herein can also be used in the present invention.
The beta-SiAlON fluorescent powder is very important for developing white light LEDs, and the price and price of the market are higher. At present, the beta-SiAlON fluorescent powder patent is strictly controlled by various countries, and particularly, Japan is in monopoly in the field of the beta-SiAlON fluorescent powder. The situation strictly restricts the further development of the beta-SiAlON fluorescent powder. Therefore, the invention provides a new process flow which is simpler and more effective, and silicon powder, Al (OH) and the like are mixed by a one-step high-temperature solid phase method3Fully mixing with a europium source and grinding; then the ground powder is put into a tube furnace in N2Heating the tube furnace to a specified temperature in the atmosphere, preserving the temperature, cooling to room temperature after the reaction is finished, grinding to obtain the cyan luminescent phosphor (beta-SiAlON: Eu), avoiding the use of a vacuumizing process and the use of a reducing carbon material, ensuring that the synthesis temperature is low, recycling waste silicon crystal leftover materials, and obtaining the beta-SiAlON luminescent phosphor with a cyan luminescent effect.
The invention relates to beta-sialon (Si)5AlON7) The synthesis method of the cyan luminescent phosphor comprises the following steps:
s1, grinding and sieving the waste crystal silicon crushed materials to form silicon powder;
and grinding the waste crystalline silicon crushed materials, and sieving the ground materials by a sieve of 50-300 meshes to obtain silicon powder.
S2, mixing the silicon powder obtained in the step S1 with Al (OH)3Mixing the Eu source and the Eu source according to the mass ratio of 1 (0.3-2.4) to 0.2-1, and grinding to obtain mixture powder;
preferably, the Eu source is europium nitrate or europium acetate.
S3, putting the mixture powder ground in the step S2 into a crucible and a tube furnace;
s4, introducing inert gas piece washing gas into the tubular furnace in the step S3, then heating the tubular furnace, and raising the temperature for three times to enable the reaction temperature to be 1350-1500 ℃;
preferably, the inert gas is high-purity nitrogen, and the flow rate of the high-purity nitrogen is 40-300 sccm.
The temperature mechanism of the third temperature rise is as follows:
heating to 1000 ℃ at the speed of 10 ℃/min, heating to 1300 ℃ at the speed of 4 ℃/min, heating to 1350-1500 ℃ at the speed of 2 ℃/min, and preserving heat for 3-5 h.
S5, after the sintering treatment is finished, cooling to room temperature along with the furnace and taking out to obtain beta-sialon (Si)5AlON7) Cyan emitting phosphor (beta-SiAlON: Eu).
Beta-sialon (Si) prepared by the method of the invention5AlON7) The cyan luminescent phosphor has bright cyan luminescence under the excitation of a 365nm ultraviolet lamp and has excellent thermal stability and chemical stability; white LED light sources can be obtained by blue light excitation.
The invention has the advantages of simple raw materials, simple synthesis method and short heat preservation time, and is very suitable for large-scale industrial production.
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of the embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example 1
Grinding waste crystal silicon crushed aggregates, sieving with a 50-mesh sieve to form powder, and then mixing silicon powder, Al (OH)3Mixing europium nitrate according to the mass ratio of 1:0.3:0.2, fully grinding and mixing; and then placed in a tube furnace. To pairAnd introducing nitrogen into the high-temperature tubular furnace, wherein the flow rate of the nitrogen is 80sccm, so that a sufficient nitrogen source is ensured in the furnace cavity. The temperature rise profile of the tube furnace is such that it first reaches 1000 ℃ at a rate of 10 ℃/min, then reaches 1300 ℃ at a rate of 4 ℃/min, and finally reaches 1350 ℃ at a rate of 2 ℃/min. Keeping the temperature at the temperature for 5h, cooling to room temperature after the reaction is finished, taking out a sample, and grinding to obtain the cyan luminescent phosphor (beta-SiAlON: Eu).
FIG. 1 shows a Scanning Electron Micrograph (SEM) of the obtained beta-SiAlON: Eu phosphor nano-material, and the SEM shows that the obtained beta-SiAlON: Eu phosphor shows irregular morphology, and the size of the powder is hundreds of nanometers small and several microns large.
Example 2
Grinding waste crushed crystalline silicon, sieving with 100 mesh sieve to obtain powder, and mixing with silicon powder, Al (OH)3Mixing europium acetate according to the mass ratio of 1:2.4:0.4, fully grinding and mixing; and then placed in a tube furnace. And introducing nitrogen into the high-temperature tubular furnace, wherein the flow rate of the nitrogen is 40sccm, so that a sufficient nitrogen source is ensured in the furnace cavity. The temperature rise profile of the tube furnace is such that it first reaches 1000 ℃ at a rate of 10 ℃/min, then reaches 1300 ℃ at a rate of 4 ℃/min, and finally reaches 1400 ℃ at a rate of 2 ℃/min. Keeping the temperature at the temperature for 3h, cooling to room temperature after the reaction is finished, taking out a sample, and grinding to obtain the cyan luminescent phosphor (beta-SiAlON: Eu).
Fig. 2 is an emission spectrum of the material under 365nm ultraviolet light excitation, and the emission spectrum shows that the main emission peak of the synthesized fluorescent powder is in a green band, is mainly concentrated at 550 nm, and a blue luminescence appears at 450 nm, which is why the synthesized fluorescent powder is cyan seen by naked eyes.
Example 3
Grinding waste crystal silicon crushed aggregates, sieving with a 200-mesh sieve to form powder, and then mixing silicon powder, Al (OH)3Mixing europium nitrate according to the mass ratio of 1:1.08:0.65, fully grinding and mixing; then putting the mixture into a tube furnace; and introducing nitrogen into the high-temperature tubular furnace, wherein the flow rate of the nitrogen is 150sccm, and ensuring that a sufficient nitrogen source is arranged in the furnace cavity. The temperature rise curve of the tube furnace is that the tube furnace is heated to 1000 ℃ at the speed of 10 ℃/minThen the temperature is increased to 1300 ℃ at the speed of 4 ℃/min, and finally the temperature is increased to 1470 ℃ at the speed of 2 ℃/min; keeping the temperature at the temperature for 4h, cooling to room temperature after the reaction is finished, taking out a sample, and grinding to obtain the cyan luminescent phosphor (beta-SiAlON: Eu).
FIG. 3 shows the X-ray diffraction pattern of the obtained nanometer material, the obtained powder is scanned at 10-50 deg.C by X-ray diffractometer, and the powder sample shows polycrystalline diffraction characteristics, all diffraction peaks and beta-SiAlON (Si)5AlON7) The standard card (PDF # 93-003-.
Example 4
Grinding waste crystal silicon crushed aggregates, sieving with a 300-mesh sieve to form powder, and then mixing silicon powder, Al (OH)3Mixing europium nitrate according to the mass ratio of 1:1.8:0.79, fully grinding and mixing; then putting the mixture into a tube furnace; introducing nitrogen into the high-temperature tubular furnace, wherein the flow rate of the nitrogen is 200sccm, and ensuring that a sufficient nitrogen source is arranged in the furnace cavity; the temperature rise curve of the tube furnace is that the temperature rises to 1000 ℃ at the speed of 10 ℃/min, then to 1300 ℃ at the speed of 4 ℃/min, and finally to 1480 ℃ at the speed of 2 ℃/min; keeping the temperature for 3h at the temperature, cooling to room temperature after the reaction is finished, taking out a sample, and grinding to obtain the cyan luminescent phosphor (beta-SiAlON: Eu).
FIG. 4 shows the X-ray diffraction pattern of the obtained nano material, the obtained powder is scanned at 10-50 ℃ by an X-ray diffractometer, and a powder sample shows the polycrystalline diffraction characteristics, all diffraction peaks and beta-SiAlON (Si)5AlON7) The standard card (PDF # 93-003-.
Example 5
Grinding waste crystal silicon crushed aggregates, sieving with a 250-mesh sieve to form powder, and then mixing silicon powder, Al (OH)3Mixing europium acetate according to the mass ratio of 1:2.1:1, fully grinding and mixing; then putting the mixture into a tube furnace; introducing nitrogen into the high-temperature tubular furnace, wherein the flow rate of the nitrogen is 300sccm, and ensuring that a sufficient nitrogen source is arranged in the furnace cavity; the temperature rise curve of the tube furnace is that the temperature rise curve is firstly at the speed of 10 ℃/minTo 1000 ℃, then to 1300 ℃ at a rate of 4 ℃/min, and finally to 1500 ℃ at a rate of 2 ℃/min; keeping the temperature for 3h at the temperature, cooling to room temperature after the reaction is finished, taking out a sample, and grinding to obtain the cyan luminescent phosphor (beta-SiAlON: Eu).
FIG. 5 shows the X-ray diffraction pattern of the obtained nano material, the obtained powder is scanned at 10-50 ℃ by an X-ray diffractometer, and a powder sample shows the polycrystalline diffraction characteristics, all diffraction peaks and beta-SiAlON (Si)5AlON7) The standard card (PDF # 93-003-.
The LED is prepared by adopting a fluorescent chip of 450 nanometers, and the prepared LED presents bright white luminescence through naked eyes. Demonstration of synthetic beta-sialon (Si)5AlON7) The cyan luminescent phosphor has important and wide application prospect in the aspect of white LEDs.
In summary, the present invention is a beta-sialon (Si)5AlON7) The cyan luminescent phosphor and the synthesis method thereof are simple and easy to implement, have good repeatability, can meet the requirements of mass production, and the prepared nano material has very low thermal quenching property and very strong luminous intensity and is suitable for the phosphor of a high-power LED.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.