KR100364493B1 - Process for preparing BAM phosphors - Google Patents

Abstract

The present invention relates to a method for producing a barium magnesium aluminate (BAM) -based blue phosphor, more specifically barium magnesium aluminate (BaMgAl ₁₀ O ₁₇ ) as a phosphor matrix, and europium (Eu ²⁺ ) as an activator The present invention relates to a method for producing a barium magnesium aluminate (BAM) -based blue phosphor represented by the following Chemical Formula 1 suitable for a lamp and a plasma display panel (PDP) by searching for a composition in which the luminous luminance is optimized in UV. .

Ba _ab Mg _c Al _d O _{a + b + c + 3 / 2d} : Eu _b

In Formula 1, 0.5 ≦ a ≦ 1.5, 0 <b ≦ 0.3, 0.5 ≦ c ≦ 1.5, and 0 <d ≦ 20.

Description

Process for preparing barium magnesium aluminate-based blue phosphor {Process for preparing BAM phosphors}

The present invention relates to a method for producing a barium magnesium aluminate (BAM) -based blue phosphor, more specifically barium magnesium aluminate (BaMgAl ₁₀ O ₁₇ ) as a phosphor matrix, and europium (Eu ²⁺ ) as an activator The present invention relates to a method for producing a barium magnesium aluminate (BAM) -based blue phosphor represented by the following Chemical Formula 1 suitable for a lamp and a plasma display panel (PDP) by searching for a composition in which the luminous luminance is optimized in UV. .

Formula 1

Ba _ab Mg _c Al _d O _{a + b + c + 3 / 2d} : Eu _b

In Formula 1, 0.5 ≦ a ≦ 1.5, 0 <b ≦ 0.3, 0.5 ≦ c ≦ 1.5, and 0 <d ≦ 20.

Plasma Display Panel (hereinafter referred to as 'PDP') is one of the next-generation flat panel displays that can supplement and replace the disadvantage of the cathode ray tube (CRT), which has been most used as an information display display. The plasma display panel (PDP) is a new type of display using a plasma phenomenon of a mixed gas such as neon, xenon, argon, and the like and is based on excitation by vacuum ultraviolet rays of 147 nm. By the way, since the phosphor which is excited by the vacuum ultraviolet rays of 200 nm or less uses an excitation mechanism different from the fluorescent substance for CRT and lamp, the fluorescent substance suitable for this is needed.

In order to satisfy these requirements, phosphors such as BaMgAl ₁₀ O ₁₇ : Eu, BaMgAl ₁₄ O ₂₃ : Eu, BaMgAl ₁₂ O ₂₀ : Eu, BaMg ₂ Al ₁₆ O ₂₇ : Eu, and the like have been reported as blue phosphors for PDP. Data on the analysis and comparison of optical characteristics of each phosphor are still insufficient.

Thus, the present inventors, of course, adding the active agent europium (Eu ²⁺ ) to the barium magnesium aluminate (BaMgAl ₁₀ O ₁₇ ) by using a combination chemistry during several attempts to solve the conventional problems as described above, By analyzing the optical characteristics according to the composition change of the phosphor matrix, the present invention was completed by searching for an optimum composition having high luminance in the UV region.

Accordingly, an object of the present invention is to provide a method for producing a BAM-based blue phosphor suitable for a lamp and a plasma display panel (PDP) by exhibiting high luminance in the UV region.

1 is a graph showing the relative luminance according to the addition amount and firing temperature of the activator europium in the BAM-based blue phosphor of the present invention,

2 is a graph showing the relative luminance according to the composition change of Ba in the BAM-based blue phosphor of the present invention,

3 is a graph showing the relative luminance according to the composition change of Mg in the BAM-based blue phosphor of the present invention,

4 is a graph showing relative luminance according to the composition change of Al in the BAM-based blue phosphor of the present invention.

The present invention is characterized by the barium magnesium aluminate (BAM) -based blue phosphor represented by the following formula (1).

Formula 1

Ba _ab Mg _c Al _d O _{a + b + c + 3 / 2d} : Eu _b

In Formula 1, 0.5 ≦ a ≦ 1.5, 0 <b ≦ 0.3, 0.5 ≦ c ≦ 1.5, and 0 <d ≦ 20.

In addition, the present invention is 0.5 to 1.5 molar ratio of barium carbonate (BaCO ₃ ), 0.5 to 1.5 molar ratio of magnesium oxide (MgO) and 9 to 15 molar ratio of aluminum powder (Al powder), 0.005 to 0.21 of activator europium oxide (Eu ₂ O ₃ ) Each precursor solution was prepared by dissolving in nitric acid in a molar ratio and adding distilled water, and then, preparatively mixed, dried, and dried in a reactor according to the formula (1), and then dried under a reducing atmosphere of nitrogen gas containing 5 to 25% hydrogen gas. It includes a method for producing a barium magnesium aluminate (BAM) -based blue phosphor represented by the formula (1) prepared by firing at a temperature of 1400 ℃.

The present invention will be described in more detail as follows.

The barium magnesium aluminate (BAM) -based phosphor of the present invention is a phosphor that is being researched a lot as a blue phosphor for lamps and PDPs, and Ba-Mg-Al-O (hereinafter referred to as 'BAM') is used as a mother. There exists BAM (BaMgAl ₁₀ O ₁₇ ) having a beta -alumina crystal structure. The present invention adds activator europium (Eu ²⁺ ) having luminous efficiency and stable physical properties by vacuum ultraviolet (VUV) excitation to BAM (BaMgAl ₁₀ O ₁₇ ), and is a barium magnesium aluminate-based blue using pyrolysis and combination chemistry. It relates to a phosphor and a method for producing the same. In particular, the present invention is characterized by searching for the optimum conditions by analyzing the optical properties according to the calcination temperature of the BAM system, the addition amount of the activator, and the composition ratio of the parent.

The BAM-based phosphor according to the present invention will be described in more detail based on the preparation method as follows.

First, the present invention prepares a precursor solution by dissolving each phosphor raw material and active agent in nitric acid and then adding distilled water. In this case, as the precursor of the phosphor raw material and the activator, metal salts and organometallic compounds that are well soluble in a solvent may be used, and nitrate is particularly preferable as the precursor. In the present invention, barium carbonate (BaCO ₃ ), magnesium oxide (MgO) and aluminum powder (Al powder) are used as the phosphor raw material, and europium oxide (Eu ₂ O ₃ ) is used as the activator. Thus, as the precursor solution, barium nitrate (Ba (NO ₃ ) ₂ ), magnesium nitrate (Mg (NO ₃ ) ₂ ), aluminum nitrate (Al (NO ₃ ) ₃ ) and europium nitrate (Eu (NO ₃ ) ₃ ) can be exemplified.

In the present invention, the barium is added at 0.5 to 1.5 molar ratio, preferably 0.9 to 1.1 molar ratio with respect to the phosphor matrix, but if the amount thereof is less than 0.5 molar ratio, incomplete crystals are formed, whereas when the molar ratio exceeds 1.5 molar ratio, the mother to killer It is not preferable because it acts and brightness decreases.

In the present invention, magnesium is added in a molar ratio of 0.5 to 1.5 moles, preferably 0.9 to 1.1 molar ratios with respect to the fluorescent substance matrix. If the amount is less than 0.5 molar ratios, incomplete crystals are formed. This is not preferable because the luminance decreases. In particular, when no magnesium is added, BaAl ₁₂ O ₁₉ is synthesized, and exhibits different optical properties from BAM.

In addition, in the present invention, aluminum is added in a 9 to 15 molar ratio, preferably 10 to 12 molar ratio with respect to the phosphor matrix, but if the amount is less than 9 molar ratio, an incomplete crystal is formed, whereas when the molar ratio exceeds 15 molar, the killer in the mother It is not preferable because the luminance decreases due to the action of. In particular, BaMgAl ₁₂ O ₂₀ : Eu is synthesized when aluminum is added in a 12 molar ratio, and BaMgAl ₁₄ O ₂₃ : Eu is synthesized when added in a 14 molar ratio. It shows the best luminous intensity.

In addition, the europium used as an activator in the present invention is added in an amount of 0.005 to 0.3 molar ratio, preferably 0.08 to 0.15 molar ratio with respect to 1 mole of the fluorescent substance matrix, and if the amount is less than 0.005 molar ratio, it functions as an active agent. There is a problem that it does not become a sufficient amount, on the other hand, if it exceeds 0.3 molar ratio, it is not preferable because the luminance decrease due to the concentration quenching effect occurs.

After the above process, the present invention is added to the alumina reactor by separating the respective precursor solution of the barium, magnesium, aluminum and europium to each composition ratio according to the composition of Formula 1, and then put the reactor in an electric furnace 400 It dries for 10 minutes-2 hours at the temperature of -600 degreeC. In the present invention, it is preferable to make the temperature increase rate at the time of drying as slow as possible so as not to overflow the precursor solution during drying.

Next, the present invention calcined the dried reactor for 1 to 6 hours at a temperature of 1200 ~ 1400 ℃ using an electric furnace. In the electric furnace atmosphere of the present invention, nitrogen (N ₂ ) gas containing 5-25% of hydrogen (H ₂ ) gas is used for the reducing atmosphere. At this time, the firing temperature is very important, if the firing temperature is less than 1200 ℃ BAM crystals are not completely produced, the light emission does not occur well, whereas if it exceeds 1400 ℃ there is a problem that the brightness is lowered by over-reaction.

In the present invention, when firing is completed at the above temperature, the sample is cooled to a temperature of 200 ° C. per hour. Then, the fired sample powder is irradiated with a production phase using an X-ray diffractometer, and UV at 254 nm is measured. As a result, it was confirmed that the BAM-based blue phosphor according to the present invention exhibited a strong emission spectrum in the 450 nm region and had high luminance.

The BAM-based blue phosphor prepared in the present invention as described above has excellent luminescence brightness and color purity in UV, stable properties at high vacuum, and high brightness, and thus can be used in lamps and PDPs.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited by Examples.

Example 1 Ba _1-x Eu _x MgAl ₁₀ O ₁₇ Composition change (x = 0∼0.21)

After dissolving barium carbonate (BaCO ₃ ), magnesium oxide (MgO), aluminum powder (Al powder) and europium oxide (Eu ₂ O ₃ ) in nitric acid, distilled water was added to prepare a nitrate precursor solution. After mixing to a composition of x mol, europium x mol, magnesium 1 mol, aluminum 10 mol and mixed in the reactor, the reactor was dried for 1 hour at 500 ℃ using an electric furnace. The dried samples in the reactor were mixed and calcined for 2 hours at 1200 to 1400 ° C. under a reducing atmosphere with nitrogen gas mixed with 25% hydrogen using an electric furnace. Thus, the blue phosphor represented by Ba _1-x Eu _x MgAl ₁₀ O ₁₇ was obtained, changing content of the activator europium to 0-0.21 mol. Thereafter, the resulting blue phosphor was measured under the UV excitation according to the calcination temperature and the amount of active agent added, and the results are shown in FIG. 1.

As shown in FIG. 1, the emission intensity rapidly increased as the firing temperature was increased from 1200 ° C. to 1350 ° C., and at 1400 ° C., the emission intensity was similar to that of the sample fired at 1350 ° C. FIG. In the case where the active agent is not added at all, the light emission is hardly emitted, but the emission intensity increases with the amount of the active agent added up to 0.08 mole, and the luminance decreases due to the concentration quenching effect when added to 0.15 mole or more.

Example 2 Ba _x Eu _0.11 MgAl ₁₀ O _{16.11 + x} Composition change experiment of (x = 0 to 1.8)

In the same manner as in Example 1, a blue phosphor was manufactured so as to have a composition of Ba _x Eu _0.11 MgAl ₁₀ O _{16.11 + x} . Then, the emission intensity was measured by UV is shown in Figure 2 attached.

As shown in FIG. 2, the light emission intensity increased as the amount of parental barium increased, and when added to 0.9 to 1.1 mole, the light emission intensity was excellent.

Example 3 Ba _0.89 Eu _0.11 Mg _x Al ₁₀ O _{16 + x} Composition change experiment of (x = 0 ~ 2)

In the same manner as in Example 1, blue phosphors were prepared such that Ba _0.89 Eu _0.11 Mg _× Al ₁₀ O _{16 + x} was formed. Then, the emission intensity was measured by UV is shown in Figure 3 attached. When no magnesium was added, BaAl ₁₂ O ₁₉ : Eu phosphor was prepared. As the amount of magnesium added up to 0.3 mol, the luminescence intensity decreased, and when 0.4 mol or more was added, the luminescence intensity increased to 0.9 to 1.1 mol. In the case of excellent luminescence intensity.

Example 4 Ba _0.89 Eu _0.11 MgAl _x O _{2 + 3 / 2x} Composition change experiment of (x = 0 ~ 20)

In the same manner as in Example 1, blue phosphors were prepared such that Ba _0.89 Eu _0.11 MgAl _x O _{2 + 3 / 2x} was formed. Then, the emission intensity was measured by UV is shown in Figure 4 attached. Up to 10 moles, the emission intensity increased rapidly as the amount of aluminum added increased, but the emission intensity gradually decreased when added more than 12 moles.

As described above, the BAM-based blue phosphor of the present invention has different light emission intensity according to the amount of active agent added and the composition of each parent, and searched for an optimal composition having high luminance in UV, in particular, BaMgAl ₁₄ O ₂₃ : Eu, BaMgAl ₁₂ O ₂₀ : Eu, BaMg ₂ Al ₁₆ O ₂₇ : Compared with Eu phosphor, its luminescence intensity is superior, making it suitable for use as a phosphor for lamps and PDPs.

Claims (2)

delete Barium carbonate (BaCO ₃ ) 0.5 to 1.5 molar ratio, magnesium oxide (MgO) 0.5 to 1.5 molar ratio, aluminum powder (Al powder) 9 to 15 molar ratio, activator europium oxide (Eu ₂ O ₃ ) 0.005 to 0.21 molar ratio, respectively. After dissolving and adding distilled water, each precursor solution was prepared, then aliquoted into a reactor according to the following formula (1), mixed and dried, and then dried at a temperature of 1200 to 1400 ° C. under a reducing atmosphere of nitrogen gas containing 5 to 25% hydrogen gas. Method for producing a barium magnesium aluminate (BAM) -based blue phosphor represented by the following formula (1), characterized in that by firing. Formula 1 Ba _ab Mg _c Al _d O _{a + b + c + 3 / 2d} : Eu _b In Formula 1, 0.5 ≦ a ≦ 1.5, 0 <b ≦ 0.3, 0.5 ≦ c ≦ 1.5, and 0 <d ≦ 20.