KR101087032B1 - Method for producing MAS phosphor - Google Patents

Abstract

General formula M _1-X AlSiN ₃ : Ln _X (wherein 0 <x <0.4, M is Li, Ca, Ba.Sr, Mg, Y, La, Ga, Zn, Zr, Bi, and lanthanide metal ( At least one element selected from the group consisting of La, Ce), and Ln is at least one element selected from the group consisting of Ce, Pr, Eu, Tb, Dy, Ho, Sm, Yb, and Er). Weighing phosphor raw material powder necessary for synthesizing the MASN phosphor to be injected into a carbon mold, installing the carbon mold into which the phosphor raw material powder is injected into a chamber of a discharge plasma sintering apparatus, and removing oxygen in the chamber; Pressing and heating the phosphor raw material powder to perform sintering, and pulverizing the sintered body obtained by the sintering to obtain a phosphor powder having a composition of the general formula is provided.

Description

Fabrication method for MASN phosphor

The present invention relates to a method for producing an M-AlSiN-based phosphor (hereinafter referred to as 'MASN phosphor'), and more particularly, to produce a MASN phosphor having low surface defects and excellent luminescence properties at a low temperature for a short time. It is about a method.

InGaN-based white light emitting diodes are attracting attention as next-generation lighting for their high efficiency, long life and high durability. White expression based on light emitting diodes is used in combination with Y ₃ Al ₅ O ₁₂ : Ce ³⁺ (YAG: Ce) phosphor that emits yellow light to a blue light emitting diode. White light obtained in this manner has a high luminance but lacks a red component and has a limitation of color temperature in expressing warm white light or warm white light. Accordingly, nitride or oxynitride phosphors, which replace the YAG phosphors lacking red components, have recently attracted much attention. Nitride or oxynitride phosphors are known to exhibit excellent properties as light emitting diode phosphors used in high-power illumination due to their excellent covalent bonds compared to oxide phosphors, resulting in excellent luminous efficiency and superior thermal and chemical stability compared to oxide phosphors and sulfide phosphors. have. In particular, the MASN phosphor has a deterioration characteristic and has a wide light emission wavelength range from yellow to red by composition control, and has attracted particular attention.

As a method for synthesizing MASN phosphors, hot equivalent pressure sintering (HIP) has been reported. However, when using such a synthesis method, a high N ₂ pressure condition of 1900 atm as well as a high temperature of 1900 degrees or more is required, and there is a disadvantage of an increase in manufacturing cost and a long time required for the synthesis of phosphors. Therefore, there is a need for development of improved synthesis of MASN phosphors.

Accordingly, the problem to be solved by the present invention is to provide a method for producing a MASN phosphor having a low surface defects and excellent luminescent properties at a low temperature for a short time.

According to an aspect of the present invention, there is provided a method for producing a MASN phosphor, wherein the method for producing a MASN phosphor is a general formula M _1-X AlSiN ₃ : Ln _X (0 <x <0.4, and M is Li, Ca, Ba.Sr). , Mg, Y, La, Ga, Zn, Zr, Bi, and at least one element selected from the group consisting of lanthanide metals (excluding La and Ce), and Ln is Ce, Pr, Eu, Tb, Dy, Ho Weighing the phosphor raw material powder required for the synthesis of the MASN phosphor represented by one or more elements selected from the group consisting of Sm, Yb, and Er, and inputting the same into a carbon mold; Installing the carbon mold into which the phosphor raw material powder is injected into a chamber of a discharge plasma sintering apparatus and removing oxygen in the chamber; Pressurizing and heating the phosphor raw material powder to perform sintering; And grinding the obtained sintered body after the sintering to obtain a phosphor powder having the composition of the general formula.

According to an embodiment, the phosphor raw material powder includes the precursor material of M, the precursor material of aluminum (Al), silicon nitride, and the precursor material of Ln.

According to one embodiment, M is Ca or comprises Ca and Sr, where Ln is represented by Eu.

According to one embodiment, the step of performing the sintering is carried out by increasing the temperature at a temperature increase rate of 50 to 200 ℃ / min and pressurized to a pressure of 1 to 50 Mpa at a holding temperature of 1400 to 2000 ℃.

MASN phosphor manufacturing method according to another aspect of the present invention, Li, Ca, Ba. Sr, Mg, Y, La, Ga, Zn, Zr, Bi and metal precursor materials comprising at least one element selected from the group consisting of lanthanide metals (except La and Ce), silicon nitride and Ce, Pr, Eu Preparing a phosphor raw material powder comprising a metal precursor material, an Al precursor material, and silicon nitride including at least one element selected from the group consisting of Tb, Dy, Ho, Sm, Yb, and Er; Weighing the phosphor raw material powder into a carbon mold with a carbon punch; Installing the carbon mold into which the phosphor raw material powder is injected into a chamber of a discharge plasma sintering apparatus and removing oxygen in the chamber; Pressurizing and heating the phosphor raw material powder to perform sintering; And pulverizing the obtained sintered body after the sintering to obtain a MASN phosphor.

According to an embodiment, the carbon punch and the carbon mold may be coated with boron nitride (a slurry of nitride such as BN) in a portion in contact with the phosphor raw material powder.

According to the present invention, the MASN phosphor having less surface defects and excellent luminescence properties can be manufactured at a low temperature in a short time. In the present invention, general formula M _1-X AlSiN ₃ : Ln _X (0 <x <0.4, M is Li, Ca, Ba.Sr, Mg, Y, La, Ga, Zn, Zr, Bi, and lanthanide metal) (Except La, Ce) is one or more elements selected from the group consisting of, Ln is at least one element selected from the group consisting of Ce, Pr, Eu, Tb, Dy, Ho, Sm, Yb and Er) The displayed quality MASN phosphors can be easily produced at relatively low temperatures using discharge plasma sintering. In addition, by coating boron nitride on a portion of the carbon mold and / or the carbon punch in contact with the phosphor raw material powder, it is possible to minimize contamination by carbon that may occur during sintering. In addition, contamination can be minimized through sintering made within an optimum temperature range.

1 is a process flow chart showing a method of manufacturing a MASN phosphor using a discharge plasma sintering method.
2 is a graph showing an X-ray diffraction pattern according to the discharge plasma sintering temperature.
Figure 3 is manufactured according to one embodiment of the present invention _{(2 Ca 0 Sr 0 8.} .) 0.995 AlSiN 3: Eu 0. ₀₀₅ is a graph showing the light emission intensity of the phosphor.
4 is a graph showing the X-ray diffraction pattern of the SCASN phosphor according to the type and ratio of the metal M of the SCASN phosphor prepared according to the present invention.
5 is a graph showing the emission spectrum according to the ratio of the metal M of the SCASN phosphor prepared according to the present invention.
6 is an X-ray diffraction analysis result according to the Eu doping concentration of the SCASN phosphor prepared according to the present invention.
7 is a graph showing the photoluminescence intensity according to the Eu doping concentration of the SCAN phosphor prepared according to the present invention.

According to the manufacturing method of the MASN phosphor of the present disclosure, a phosphor having the following general formula can be produced by spark plasma sintering (SPS).

M _1-X AlSiN ₃ : Ln _X

The metal M is Li, Ca, Ba. Sr, Mg, Y, La, Ga, Zn, Zr, Bi and lanthanide metal (except La, Ce) may be at least one element selected from the group, the lanthanide metal Ln is Ce, Pr, It may be one or more elements selected from the group consisting of Eu, Tb, Dy, Ho, Sm, Yb and Er. Particularly, in the case where the metal M includes Sr and Ca, and the phosphor using Eu as the lanthanide metal Ln, sulfur-red light emission having a wavelength range of about 600 to 650 nm is preferable, thus obtaining a white light emitting diode. Do.

When manufacturing a MASN phosphor by using an SPS device, it is possible to obtain a MASN phosphor, which generally forms a single phase and has a very high emission intensity. Specifically, the MASN phosphor may be prepared by the following method.

1 is a process flow chart showing a method of manufacturing a MASN phosphor using a discharge plasma sintering method. 1, in the step S1, the general formula M _1-X AlSiN ₃ : Ln _X (wherein, 0 <x <0.4, M is Li, Ca, Ba.Sr, Mg, Y, La, Ga, Zn, Zr, Bi and at least one element selected from the group consisting of lanthanide metals (excluding La and Ce), and Ln is a group consisting of Ce, Pr, Eu, Tb, Dy, Ho, Sm, Yb and Er Phosphor raw material powder required for the synthesis of the MASN phosphor represented by (at least one element selected from)) is weighed and put into the carbon mold. At this time, by coating a portion of the carbon mold used in the sintering contact with the raw powder, such as carbon punch with boron nitride (slurry of nitride such as BN) it can minimize the contamination by carbon that may occur during sintering.

As the phosphor raw material powder, a precursor material of metal M, a precursor material of aluminum (Al), silicon nitride, and a precursor material of Eu may be used.

The precursor material of the metal M may be an oxide or nitride of the metal.

The precursor material of aluminum may be at least one selected from the group consisting of aluminum nitride and aluminum oxide.

The precursor material of Eu may be a nitride material, an oxynitride, an oxide of Eu, or a precursor material which becomes an oxide by pyrolysis.

For example, the MASN phosphor is Sr ₀ doped with europium (Eu) using calcium and strontium as metal M. ₂ Ca ₀ . _{In the case of 8} AlSiN ₃ , the phosphor powder may be used together with strontium oxide powder, calcium oxide powder, silicon nitride powder, aluminum nitride powder, and europium oxide powder.

In step S2, the carbon mold into which the phosphor raw material powder is injected is installed in a chamber of a discharge plasma sintering apparatus, and oxygen in the chamber is removed. Vacuum may be applied to remove oxygen to maintain the pressure in the chamber at 50 to 200 mTorr, and if necessary, nitrogen gas may be injected to control the atmosphere.

In step S3, the phosphor raw material powder is pressed and heated to perform sintering. At this time, the temperature increase rate can be adjusted at a rate of 50 to 200 ℃ / min, the temperature reached can be controlled to 1400 to 2000 ℃, preferably 1600 to 1700 ℃, more preferably 1700 ℃. If the attained temperature is less than 1400 ° C., the synthesis is not performed, but if the temperature exceeds 2000 ° C., contamination by carbon infiltration may increase, resulting in deterioration of fluorescence properties. The pressure is preferably 1 to 50 MPa. After reaching the predetermined temperature, the temperature and pressure conditions are maintained for 1 to 10 minutes, and then the pressure inside the chamber is removed and cooled to obtain a sintered body.

In step S4, the sintered body obtained after the sintering is pulverized to obtain a phosphor powder having the composition of the general formula. Prior to grinding the sintered compact, the sintered compact may be polished using a polishing machine to remove carbon residues on the surface of the sintered compact. After polishing of the sintered body, grinding may be performed using alumina induction and a pestle.

The kind of metal M and the range of x which allow the MASN phosphor to have a high luminous efficiency can be appropriately selected from the above ranges.

Hereinafter, the light emission characteristics according to the composition, the sintering temperature, etc. of the MASN phosphor will be described through various embodiments.

2 is a graph showing an X-ray diffraction pattern according to the discharge plasma sintering temperature. 2, the use of strontium and calcium as the metal M, and the ratio is 2: 8, y = 0.005 MASN the phosphor, i.e., _{(Sr 0 2 Ca 0 8.} .) 0.995 AlSiN 3: Eu 0. The most preferred sintering temperature of ₀₀₅ (hereinafter referred to as SCASN) sample is 1700 ° C. When sintering at a temperature below 1700 ° C, the crystallinity of the sintered body is inferior.

3 is a graph showing the light emission intensity of the SCASN phosphor according to the sintering temperature. Referring to FIG. 3, it has high luminance at 1700 ° C. showing good crystallinity and low luminance at 1600 ° C. with relatively low crystallinity.

In the SCASN phosphor of the present disclosure, the formation pattern on the SCASN may be different according to the change in the strontium and calcium ratio.

4 is a graph showing the X-ray diffraction pattern of the SCASN phosphor of the present disclosure according to the type and ratio of the metal M. SCASN was prepared by sintering and pulverizing at 1700 ° C. for 5 minutes using SPS. The prepared SCASN phosphor used strontium and calcium as the metal M in the above formula, and controlled the ratio of strontium and calcium and x = 0.005 days. The X-ray diffraction pattern in the case is shown. Referring to FIG. 4, a change in phase when strontium is at 0%, 20% and at 50% and 80% is observed.

5 is a graph showing the emission spectrum of the SCASN phosphor of the present disclosure according to the ratio of the metal M. Referring to FIG. 5, the SCASN phosphor may exhibit the best photoluminescence (PL) intensity at an excitation wavelength of 460 nm.

6 is an X-ray diffraction analysis of SCASN phosphors according to the Eu doping concentration. Referring to FIG. 6, there is no change in phase even if the Eu doping concentration x is changed from 0.003 to 0.015 for SCASN phosphors (80% strontium and 20% calcium) sintered at 1700 ° C. for 5 minutes.

7 is a graph showing the photoluminescence intensity of the SCASN phosphor according to the Eu doping concentration. Referring to FIG. 7, at an excitation wavelength of 460 nm, it is observed that the photoluminescence intensity increases rapidly as the doping concentration increases in the range of x = 0.003 to 0.008. Rather decrease is observed. While not being bound by a particular theory, this phenomenon may be related to doping concentration quenching that occurs when the distance between the doped ions in the lattice with the increase of the doping concentration falls below a critical distance.

1 to 7, the SCASN phosphor can be synthesized in the case of using the discharge plasma sintering apparatus, and an example of the composition and conditions showing the optimal luminescence properties is as follows.

[Discharge plasma sintering: hold at 1700 ° C. for 5 minutes, metal M is strontium 80%, calcium 20%, Eu (x = 0.008)]

From the above, it will be appreciated that various embodiments of the present disclosure have been described for purposes of illustration and that there are various modifications possible without departing from the scope and spirit of the present disclosure. And, the various disclosed embodiments are not intended to limit the present disclosure, and the true spirit and scope will be set forth in the claims below.

S1: Injecting phosphor raw material into carbon mold
S2: Injecting the carbon mold into the plasma sintering apparatus
S3: Sintered
S4: sintered compact, phosphor acquisition

Claims (8)

Weighing the phosphor raw material powder required for the synthesis of the MASN phosphor represented by the general formula M _1-X AlSiN ₃ : Ln _X (0 <x <0.4, M contains Ca and Sr, and Ln is Eu), Injecting;
Installing the carbon mold into which the phosphor raw material powder is injected into a chamber of a discharge plasma sintering apparatus and removing oxygen in the chamber;
Pressing and raising the phosphor raw material powder to perform sintering; And
Grinding the sintered body obtained after the sintering to obtain a phosphor powder having the composition of the general formula,
In the step of weighing and injecting the phosphor raw material powder into the carbon mold, the phosphor raw material powder is prepared MASN phosphor, characterized in that it comprises a strontium nitride powder, silicon oxide powder, silicon nitride powder, aluminum nitride powder and europium oxide powder Way. The method according to claim 1,
The MASN phosphor is Sr _y Ca _1-y AlSiN ₃ (0.1 <y <0.9) doped with europium (Eu). delete The method according to claim 1,
The step of performing the sintering is a method for producing a MASN phosphor is carried out by pressing at a pressure of 1 to 50 Mpa at a holding temperature of 1400 to 2000 ℃ after raising the temperature at a heating rate of 50 to 200 ℃ / min. delete delete delete delete

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