KR20120096221A - Phosphor powders and preparing method of the same - Google Patents

Abstract

PURPOSE: A manufacturing method of phosphor powder is provided to provide oxynitride-based or nitride-based phosphor powder emitting blue to yellow excitation light in a range of blue ray to ultra violet ray, and having excellent luminous efficiency and temperature performance even in high temperatures. CONSTITUTION: A manufacturing method of phosphor powder comprises a step of obtaining precursor by impregnating aqueous solution comprising divalent metal salt for forming Si-based oxynitride group through hydrothermal synthesis at 80-200 °C; and a step of primary sintering the precursor at 300-800 °C under oxygen-containing atmosphere; a step of secondary sintering under ammonia- or nitrogen-containing atmosphere at 900-1400 °C.

Description

Phosphor powder and its manufacturing method {PHOSPHOR POWDERS AND PREPARING METHOD OF THE SAME}

The present application relates to a method for producing a phosphor powder and a phosphor powder thereby, comprising impregnating an aqueous solution containing a metal salt for forming a phosphor into a polymer material by using a hydrothermal synthesis method to obtain a precursor and firing in two steps. The present invention relates to a method for producing a phosphor powder and a phosphor powder thereby.

Phosphors are used in vacuum fluorescent displays (VFDs), field emission displays (FEDs), plasma display panels (PDPs) or light emitting diodes (LEDs). In any of these phosphors, excitation energy for exciting the phosphor is required, and the energy is excited by excitation light having high energy such as vacuum ultraviolet ray, ultraviolet ray, electron beam or blue light to generate visible light. However, these phosphors have a problem of prolonged exposure to high energy excitation light, deterioration in luminance or poor color rendering index due to heat or moisture generated from the use of the device, thereby solving the so-called temperature quenching problem. There is a need for a phosphor that can be used.

As one solution to solve the above problems, oxynitride and nitride phosphors are used, but the synthesis of such phosphors is most of the solid-state reaction at high temperature of 1800 ~ 2000 ℃ and high pressure of 10 ~ 100 atm. In addition, there is a problem that the raw material is expensive because most of the starting material from the nitride material, it is difficult to obtain a uniform phosphor during synthesis.

In addition, in order to use the phosphor usefully for the above-mentioned use, there is a need for improvement of RGB light emission for realizing a mother and high color rendering of the phosphor which is efficiently excited for each use.

The conventional method of preparing a nitride phosphor by a carbon thermal reduction and nitridation (CRN) method using carbon from an oxide phosphor has a problem in that it is difficult to control the amount of carbon. That is, the remaining carbon reacts with oxygen during the sintering process, and the carbon is nitrated through a chemical reaction with nitrogen in the air at an empty position of the carbon. In this process, some of the remaining carbon does not react with oxygen, thereby lowering the luminous efficiency and Carbide materials are synthesized when the carbon balance is higher. This problem of the prior art is mainly caused by using a carbon material in the form of mixing a carbon material such as graphite or graphene of several μm with an oxide phosphor material. In addition, there has been a problem that the conventional method is not suitable for producing a multi-component phosphor.

The present application is to provide a method for producing a phosphor powder and a phosphor powder thereby comprising impregnating an aqueous solution containing a metal salt for phosphor formation in a polymer material by using hydrothermal synthesis to obtain a precursor and calcining in two steps. do.

However, the problem to be solved by the present invention is not limited to the above-mentioned problem, another task that is not mentioned will be clearly understood by those skilled in the art from the following description.

One aspect of the present invention is to obtain a precursor by impregnating an aqueous solution containing a + divalent metal salt for forming a Si-based oxynitride-based polymer material at the temperature of 80 ℃ to 200 ℃ using a hydrothermal synthesis method; Firing the precursor first at a temperature of 300 ° C. to 800 ° C. under an oxygen-containing atmosphere and then second firing at a temperature of 900 ° C. to 1400 ° C. under an ammonia- or nitrogen-containing atmosphere. It provides a method for producing.

Another aspect of the present invention provides a phosphor powder produced by the above production method.

Another aspect of the present invention can provide a display comprising the phosphor powder as a phosphor.

Another aspect of the present invention provides a lamp comprising a powder of the phosphor as a phosphor.

The novel method for producing the phosphor powder according to the present invention comprises impregnating an aqueous solution containing a + 2-valent metal salt to form a Si-based oxynitride-based polymer material by hydrothermal synthesis to obtain a precursor and firing in two steps. The oxynitride-based or nitride-based phosphor powders obtained by the above production method include light emitted from good blue to yellow in excitation light in the blue or near-ultraviolet-ultraviolet range, and excellent temperature characteristics or luminous efficiency even at high temperatures. Indicates.

1 is a view showing a SrSiON: Eu ^{2 +} phosphor manufacturing process according to an embodiment of the present application.
Figure 2 is a graph showing the light emission characteristics of Sr ₂ SiON: Eu ^{2 +} phosphor according to an embodiment of the present application.
Figure 3 is a view showing the SEM and EDX analysis of the Sr ₂ SiON: Eu ^{2 +} phosphor according to an embodiment of the present application.

DETAILED DESCRIPTION Hereinafter, embodiments and embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention.

As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like parts throughout the specification.

Throughout the specification, when a part is said to "include" a certain component, it means that it can further include other components, except to exclude other components unless specifically stated otherwise.

One aspect of the present invention, the aqueous solution containing a + divalent metal salt for forming a Si-based oxynitride-based impregnated the polymer material using a hydrothermal synthesis method at a temperature of 80 ℃ to 200 ℃ to obtain a precursor; Firing the precursor first at a temperature of 300 ° C. to 800 ° C. under an oxygen-containing atmosphere and then second firing at a temperature of 900 ° C. to 1400 ° C. under an ammonia- or nitrogen-containing atmosphere. It provides a method for producing.

In one embodiment, the secondary firing may be performed after the primary firing, after cooling or continuously. For example, the secondary firing may be performed after cooling after the primary firing, but is not limited thereto.

In another embodiment, the + 2-valent metal may include one selected from the group consisting of magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and combinations thereof, but is not limited thereto. It doesn't happen.

In another embodiment, the oxynitride-based phosphor powder may further include Al, but is not limited thereto.

In another embodiment, the ammonia- or nitrogen-containing atmosphere during the secondary firing may be a reducing atmosphere, but is not limited thereto.

In another embodiment, the secondary firing may be performed under a pressurized atmosphere of 1 to 20 atm, but is not limited thereto.

In another embodiment, the aqueous solution containing a + 2-valent metal salt for forming the Si-based oxynitride-based may further include propylene glycol, but is not limited thereto.

In another embodiment, the polymeric material may include one selected from the group consisting of glucose, pulp, crystalline cellulose, amorphous cellulose, rayon, citric acid, urea, and combinations thereof, but is not limited thereto.

In another embodiment, the particle diameter of the phosphor powder may be 1 to 10 ㎛, but is not limited thereto.

Hereinafter, the preferred embodiment of the present invention will be described in more detail, but the present invention is not limited thereto.

In one embodiment of the present application, the oxynitride phosphor powder may be prepared, for example, as follows.

50 ml of an aqueous solution containing a + 2-valent metal salt for forming a Si-based oxynitride-based phosphor was placed in a Teflon cup, followed by an autoclave, and then subjected to hydrothermal synthesis for 12 hours at a temperature of 100 ° C. to 200 ° C. Impregnation into the polymer material yields a precursor. For example, after mixing a Si precursor with propylene glycol, a +2 valent metal salt selected from the group consisting of magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and combinations thereof, and Eu ² The precursor may be obtained by mixing with an aqueous solution including a ⁺ salt, followed by mixing with the polymer material, followed by hydrothermal reaction at a temperature of 80 ° C. to 200 ° C. using a pressure reactor.

The precursor is first calcined in an oxygen-containing atmosphere such as air to a temperature of 300 to 800 ° C. to oxidize a portion of the precursor, leaving some polymeric material and residual carbon of the precursor. The oxynitride phosphor powder is then obtained by second sintering in an ammonia- or nitrogen-containing atmosphere at a temperature of 900 to 1400 ° C. continuously or after cooling to reduce and nitride the residual carbon.

For example, the Si-based oxynitride-based phosphor further includes a + monovalent alkali metal selected from the group consisting of lithium (Li), sodium (Na), potassium (K), and combinations thereof. It may be, but is not limited thereto.

For example, the alkali metal salts, + divalent metal salts and rare earth metal salts are selected from the group consisting of chlorides, nitrates, sulfates, carbonates, and combinations thereof of the alkali metals, the + divalent metal salts and the rare earth metals, respectively. It may be, but is not limited thereto. For example, when the chloride, nitride, and sulfide of the metals are used in order, the oxide of the final composition may be synthesized at a lower temperature, and the chloride or nitride is preferably used as an aqueous metal salt solution, but is not limited thereto. .

For example, the silicon compound may be a silicon precursor compound commonly used in the art, for example, TEOS (Tetraethyl Orthosilicate), SiO ₂ sol (Sol, particle size 200 nm or less) and the like can be used However, the present invention is not limited thereto.

For example, the polymeric material may be selected from the group consisting of glucose, cellulose, amorphous cellulose, pulp, rayon, citric acid, urea, or a combination thereof as a chelating agent, and combinations thereof, but is not limited thereto. . Specifically, the polymer material may be crystalline cellulose (purity 99.99%), high purity pulp (99.8%) or rayon. For example, it is desirable to select, but is not limited to, high purity pulp having a micro matrix shape. The empty space between the matrices is preferably 40 to 250 μm. The high-purity pulp begins to be oxidized above about 200 ° C. and is removed in the form of a compound of carbon, at which time other residues are also removed. On the other hand, in the process of oxidizing the carbon remaining in the fine powder, it is possible to reduce the defects in the fine crystals, and to easily form a reducing atmosphere. In addition, phosphor powder including residual carbon may be manufactured by controlling the firing temperature.

Here, the concentration of the aqueous solution containing the metal salts (hereinafter referred to as "metal salt aqueous solution") is preferably 10 to 70% by weight concentration. When the concentration of the aqueous metal salt solution is less than 10%, productivity may be decreased because the time for the metal salt aqueous solution to be impregnated in the entire polymer material becomes longer. On the other hand, when the concentration of the aqueous metal salt solution is greater than 70%, the fluidity of the aqueous solution is lowered, thereby causing an obstacle in the process of impregnating the aqueous metal salt solution into the polymer material, and thus the metal from the surface of the polymer material to the inside of the polymer material. The aqueous salt solution may not be impregnated. That is, the concentration of the aqueous metal salt solution is more preferably 25 to 50% by weight so that fine particles are uniformly impregnated into the matrix of the polymer material.

 In the impregnation step, the weight ratio of the aqueous metal salt solution to the polymer material is preferably 1: 0.5 to 3.0. When the weight ratio of the aqueous metal salt solution to the polymer material is less than 1: 0.5, since there is a large amount of unimpregnated aqueous solution compared to the polymer material, the non-impregnated aqueous metal salt solution has a powder having large particles in the firing process. By forming, it may not be easy to prepare the phosphor powder according to the present invention. On the other hand, when the weight ratio of the aqueous solution and the polymer material is greater than 1: 3.0, since the polymer material is present in a large amount compared to the aqueous metal salt solution, the time for the polymer material to be impregnated with the metal salt increases, resulting in increased productivity. And economic efficiency may be lowered.

The primary firing is important to control the amount of residual carbon derived from the polymer material included in the phosphor precursor by heating to an temperature in the range of 300 ~ 800 ℃ in the oxygen-containing atmosphere. For example, the primary firing may be rapidly heated to a temperature in the range of 300 ~ 800 ℃ in the oxygen-containing atmosphere.

When the primary firing temperature is less than 300 ℃, by using the residual carbon formed from the polymer material at such a temperature, a carbide phosphor can be obtained after the secondary firing process due to a large amount of residual carbon, the primary When the firing temperature exceeds 800 ℃ may be an oxide phosphor after performing the secondary firing process.

After the first firing step or after the secondary firing step is carried out continuously, firing at a temperature of 900 to 1400 ℃ at a heating rate of 50 to 500 ℃ / h in a constant reducing atmosphere to a high crystalline oxynitride system Phosphor powder can be obtained. Here, when the secondary firing temperature is less than 900 ℃, it is difficult to perform the crystal formation and reduction reaction of the phosphor to be produced, the luminous efficiency of the manufactured phosphor can be sharply lowered. On the other hand, when the secondary firing temperature is more than 1400 ℃, it may not be easy to obtain a phosphor powder having a uniform particle size because the crystal growth and powder agglomeration of the phosphor to be produced rapidly progress. For example, it is more preferable that the temperature of the secondary firing process performed after cooling after the primary firing process or continuously performed is set to 1000 to 1300 ° C.

Here, the firing time of the primary firing process can be controlled to 30 minutes to 5 hours to control the carbon of the polymer material, which may vary depending on the heating temperature and the amount of the phosphor produced. On the other hand, when the firing time is less than 30 minutes, a large amount of residual carbon of the polymer material is left to become a carbide phosphor material, and if the residual carbon is more than 5 hours, most of the remaining carbon is not oxidized, thereby obtaining an oxide-based phosphor. Preferably, by setting the firing time to 1 to 2 hours, the polymer material remains as residual carbon through the firing process, and the impregnated cells of the microfiber structure of the polymer material (~ Several micrometers).

Therefore, using the carbon remaining in the fine powder due to the primary firing in the secondary firing, the carbon is vaporized in the form of CO (g) as shown in the following brief reaction, and the reaction is performed to replace the vacant sites with N ₂ (g). Can be.

[Scheme 1]

M (CO ₃ ) ₃ (s) + N ₂ (g)-> MO ₆ N ₂ (s) + 3CO (g)

[Scheme 2]

M ₂ O ₅ (s) + 3C (s) + N ₂ (g)-> M ₂ O ₂ N ₂ (s) + 3CO (g)

Schemes 1 and 2 are forms in which carbon in the fine structure of the high purity pulp is oxidized or left as residual carbon. The carbons may form a reducing atmosphere in the form of CO (g) due to secondary firing and may be replaced with nitrogen gas at the positions thereof.

In addition, the residual carbon may produce carbonated and carbide-based phosphor powders including carbon by controlling the firing temperature and the firing atmosphere.

Secondary firing in the reducing atmosphere is, for example, N ₂ / H ₂ = (90 to 95) / (5 to 10) or Ar / H ₂ = (90 to 95) / (5 to 10) can be carried out in a reducing atmosphere or more easily in an ammonia atmosphere, but is not limited thereto. no. As the reducing atmosphere gas, N ₂ / H ₂ (95/5) Mixed gas is preferred.

For example, the particle size of the oxynitride-based phosphor powder may be 0.5 to 10 ㎛, but is not limited thereto.

In another embodiment of the present invention, the secondary firing may be carried out under a pressure of 1 to 20 atm, more preferably 1 to 5 atm, but is not limited thereto. When the pressure is high pressure, gas pressure sintering (GPS) may be used.

Another aspect of the present invention can provide a phosphor powder prepared by the method for producing a phosphor powder according to the present application.

In one embodiment, the oxynitride-based phosphor may be a SiON-based or AlON-based phosphor powder, and may be represented by the following general formula (1) or (2), respectively:

[Formula 1]

(M ¹ _2a M ² _{1 -a} ) _w (M ³ _b M ⁴ _{1 -b} ) _x (M ⁴ _c Si _{1 -c} ) _y M ⁴ _d (O _{1 - e} N _{2e / 3} ) _z : L _f ,

[Formula 2]

(M ¹ _2a M ² _{1 -a} ) _w (M ³ _b ) _x Al _y (O _{1 - e} N _{2e / 3} ) _z : L _f ,

In the above formula,

M ¹ is a + monovalent alkali metal selected from the group consisting of lithium (Li), sodium (Na), potassium (K), and combinations thereof,

The M ² is a + divalent alkaline earth metal selected from the group consisting of magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), zinc (Zn), and combinations thereof.

M ³ is a + trivalent metal selected from the group consisting of boron (B), aluminum (Al), yttrium (Y), gadolinium (Gd), terbium (Tb), cerium (Ce), and combinations thereof,

The M ⁴ is +3, +4 or selected from the group consisting of phosphorus (P), vanadium (V), titanium (Ti), arsenic (As), and combinations thereof, which serve as a parent or study agent of the phosphor. Is a +5 valent metal,

L is a metal selected from the group consisting of europium (Eu), manganese (Mn), cerium (Ce), dysprosium (Dy), samarium (Sm) and combinations thereof as an activator,

A is 0 to 1, w is greater than 0 to 4,

B is 0 to 1, x is 0 to 5,

C is 0 to less than 1, y is greater than 0 to 6,

D is 0 to 3,

E is less than 0.1 to 1,

Z is greater than 2 and 54,

F is 0.001 (w + x + y + d) to 0.3 (w + x + y + d).

Here, the oxynitride-based phosphor represented by Formula 1 or Formula 2 has been adjusted from the minimum nitride material range of oxide to the previous range of complete nitride material, and the degree of difficulty and difficulty of nitriding varies depending on the constituent elements. It can be determined according to electron affinity, crystal structure or valence.

The SiON-based and AlON based phosphor powders, specifically, ^{Ca-α-SiAlON: Eu 2} +, β-SiAlON: Eu 2+, SrSi 2 O 2 N 2: Eu may be a phosphor powder, such as ^{2 +,} limited to It doesn't happen.

In addition, a pulverization process may be additionally performed on the phosphor powder produced by the above production method. As an apparatus used in the pulverization process, a ball mill, a roller mill, a vibrating ball mill, Dry disperser or ultrasonic disperser or high pressure homogenizer such as atatorita mill, planetary ball mill, sand mill, cutter mill, hammer mill, jet mill Any one or more devices of a homogenizer can be used, and the pulverization process through this device can be used to further atomize the phosphor powder.

In still another aspect of the present invention, a display including a powder of the oxynitride-based phosphor as a phosphor can be provided.

In one embodiment of the present invention, the display is a CRT, a vacuum fluorescent display (VFD), a light emitting diode (LED), a plasma display panel (PDP) and a field emission display It may be one of (Field Emission Display, FED).

In another aspect of the present invention, there can be provided a lamp comprising a powder of the oxynitride-based phosphor as a phosphor.

Hereinafter, an embodiment of a method for producing an oxynitride-based phosphor of the present invention and an oxynitride-based phosphor thereby will be described in detail with reference to the accompanying drawings. However, the present invention is not limited thereto.

Sr ₂ SiON  : Eu ^{2 +} Manufacturing

Also by a process as shown in Fig. 1, SrSiON: Eu ^{2 +} phosphor was produced.

Specifically, the Tetraethoxysilane (TEOS) solution and the Propylene glycol (PG) solution were mixed at a ratio of 1: 4 molal and then stirred at 80 ° C. for 24 hours. At this time, the TEOS layer and the PG layer were separated, and the addition of a small amount of HCl gave a transparent and uniform mixed solution. Sr _2-x SiO ₄ : xEu (x = 0.1, 0.05) Dissolved in deionized water (DIion) to match the composition, Sr (NO ₃ ) ₂ nH ₂ O / 30 wt% solution of deionized water and EuCl ₃ nH _After mixing the precursor aqueous solution containing ₂ wt% of O / deionized water, and impregnating the precursor aqueous solution with cellulose, followed by hydrothermal synthesis at 200 ° C. for 24 hours, calcining at 800 ° C. in an oxygen atmosphere, and then varying Ar + NH ₃ at 1200 ° C. or by calcination for six hours in a H ₂ + Ar + NH ₃ atmosphere Sr ₂ SiON: Eu ^{2 +} phosphor was produced.

The above prepared ₂ Sr SiON: the emission characteristics of Eu ^{2 +} phosphor is shown in Fig. As a comparative example, Sr ₂ SiO ₄ : Eu ^{2 +} phosphors were prepared and compared with the emission characteristics of the prepared Sr ₂ SiON: Eu ^{2 +} phosphors. As can be seen in Figure 2, the excitation and emission peak of the Sr ₂ SiON: Eu ^{2 +} phosphor (Fig. 2a) is confirmed to be shifted toward the longer wavelength compared to the Sr ₂ SiO ₄ : Eu ^{2 +} phosphor (Fig. 2b) It was.

Figure 3 shows the SEM and EDX analysis of the prepared Sr ₂ SiON: Eu ^{2 +} phosphor.

As mentioned above, the present invention has been described in detail by way of examples, but the present invention is not limited to the above embodiments, and may be modified in various forms, and within the technical spirit of the present invention, there is a general knowledge in the art. It is obvious that many variations are possible by the possessor.

Claims (14)

An aqueous solution containing a + 2-valent metal salt for forming an Si-based oxynitride-based material was impregnated into a high molecular material using hydrothermal synthesis at a temperature of 80 ° C to 200 ° C to obtain a precursor,
Preparation of the phosphor powder, comprising firing the precursor first at a temperature of 300 ℃ to 800 ℃ under an oxygen-containing atmosphere, and then secondary firing at a temperature of 900 ℃ to 1400 ℃ under ammonia- or nitrogen-containing atmosphere Way.
The method of claim 1,
The secondary firing is a method of producing a phosphor powder, after the primary firing, after cooling or continuously performed.
The method of claim 1,
The + 2-valent metal is one comprising magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba) and a combination thereof, the method of producing a phosphor powder.
The method of claim 1,
The oxynitride-based phosphor powder further comprises Al, the method for producing a phosphor powder.
The method of claim 1,
And said ammonia- or nitrogen-containing atmosphere in said secondary firing is a reducing atmosphere.
The method of claim 1,
The secondary firing is performed under a pressurized atmosphere of 1 to 20 atm, the method for producing a phosphor powder.
The method of claim 1,
The polymer material is selected from the group consisting of glucose, pulp, crystalline cellulose, amorphous cellulose, rayon, citric acid, urea, and combinations thereof.
The method of claim 1,
The particle size of the phosphor powder is 1 to 10㎛, the production method of oxynitride-based phosphor powder.
The method of claim 1,
A method for producing an oxynitride-based phosphor powder, wherein the aqueous solution containing a + 2-valent metal salt for forming the Si-based oxynitride system further contains propylene glycol.
A phosphor powder prepared by the method according to any one of claims 1 to 9.
11. The method of claim 10,
The powder SrSiON: Eu ^{+ 2.} CaSiON: Eu ^{2 +,} or BaSiON: is, phosphor powder comprises powdered oxynitride-based fluorescent material represented by Eu ^{+ 2.}
A display comprising the phosphor powder according to claim 10.
The method of claim 12,
The display is a cathode ray tube, a light emitting diode (LED), a plasma display panel (PDP), a field emission display (FED) or a vacuum fluorescent display (VFD).
A lamp comprising the phosphor powder according to claim 10.

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