KR20130063412A - Phosphor and method of fabricating phosphor - Google Patents

Abstract

PURPOSE: An aluminum silicate-based phosphor is excited by UV and blue light emitting diodes, and to have a light-emitting spectrum within 400-800 nm. CONSTITUTION: An aluminum silicate-based phosphor is represented by chemical formula: (M_(1-x)N_x)_4(Si_(1-y)Al_y)_8O_(16±δ):Eu^(2+)_z. In the chemical formula, each of M and N is one or more elements selected from an alkali earth metal group including Li, Na, K, Rb, and Cs; 0 <= x <= 1, 0 < y < 1, and 0 < z <= 0.5; and δ is change of non-stoichiometric molar ratio of oxygen ions, according to change of x and y. The particle size of the aluminum silicate phosphor is 0.5-20 micron. The aluminum silicate phosphor has a wavelength of 400-800 nm at an excitation wavelength of 250-500 nm.

Description

Phosphor and method of fabricating phosphor

The embodiment relates to a phosphor and a method for producing the phosphor.

White light emitting diodes (white LEDs) are one of the next-generation light emitting device candidates that can replace fluorescent light, which is one of the most typical conventional lighting. Light emitting diodes consume less power than conventional light sources, and unlike fluorescent lamps, they do not contain mercury and are thus environmentally friendly. In addition, it has the advantage of longer life and faster response speed than the conventional light source. There are three methods for manufacturing a white light emitting diode. A method of realizing white light by combining red, green and blue LED chips, A method of realizing white light by applying a yellow phosphor to a blue LED chip, and a method of realizing white light by combining red, green and blue LED chips on a UV LED chip. This is it.

In order to realize white light by combining red, green, and blue LED chips, different films such as InGaN, GaN, GaAs, and ZnO must be made. Such a manufacturing method requires manufacturing different light emitting diodes, . In addition, when the red, green, and blue LED chips are combined, the driving voltage of each LED chip is different. Therefore, there arises a problem of complexity of the manufacturing process and restriction of design due to the complicated structure of the respective circuits.

The method of applying a yellow phosphor to a blue LED chip to realize white light is currently the most widely used and is the most representative method of realizing white light by using a light emitting diode. Currently, the most widely used white light emitting diodes are manufactured by applying YAG: Ce phosphor, which is a yellow phosphor, to a blue LED chip. In the case of a method of implementing white light by combining a blue LED chip and a yellow phosphor, it is difficult to find a phosphor having a 450 nm excitation wavelength at a wavelength of 450 nm because of the difficulty in combining the blue LED chip with a phosphor. This follows. When a yellow phosphor is used as a phosphor excited by a blue LED chip, color rendering index (CRI) is lowered due to weak light emission in a red region. In addition, since the blue light source changes according to the driving voltage in the above method, the color coordinate becomes unstable.

The above problems can be solved in the case of a method of implementing white light by combining red, green, and blue phosphors in an ultraviolet LED chip or using a phosphor having an emission spectrum of a full width half maximum (FWHM). In the case of applying red, green, and blue phosphors to a long wavelength ultraviolet light emitting diode, or in the case of a yellow phosphor having a wide half width. White light close to sunlight having a high color rendering index can be produced. Therefore, there is an urgent need to develop phosphors having high color rendering and high efficiency which are excited by such ultraviolet and blue light emitting diodes.

The embodiment is intended to solve problems such as low color rendering and brightness of conventional phosphors excited by ultraviolet light and blue light emitting diodes, and is excited by ultraviolet light and blue light emitting diodes, and exhibits an emission wavelength spectrum of 400 to 800 nm. An aluminum silicate-based phosphor and a method of manufacturing a white light emitting device using the same can be provided.

In the embodiment, the aluminum silicate-based phosphor [(M _{1 - x} N _x ) ₄ (Si _{1 - y} Al) is excited in the wavelength region of 250 nm to 500 nm by ultraviolet and blue light emitting diodes and the like and exhibits the emission wavelength spectrum in the 400 nm to 800 nm region. _y ) ₈ O _{16 ± δ} : Eu ^{2 +} _z ] and a method of manufacturing the same, and a method of obtaining a luminaire having excellent light emission characteristics was examined.

Aluminum silicate-based phosphors according to the embodiment of the formula (M _{1 - x} N _x ) ₄ (Si _{1 -y} Al _y ) ₈ O _{16 ± δ} : Eu ^{2 +} _z (where M and N are Li, Na, K, At least one of alkaline earth metal elements including Rb, Cs, etc., and 0 ≤ x ≤ 1, 0 <y <1, 0 <z ≤ 0.5, δ is a non-chemistry of oxygen ions according to the change of x and y values It can be implemented as a powder based on an aluminum silicate system represented by the stoichiometric molar ratio change.

In an embodiment, the aluminum silicate-based phosphor may have one or more crystal phases of cubic, tetragonal, orthorhombic, and hexagunal.

In the embodiment, the method for producing an aluminum silicate-based phosphor represented by the chemical formula includes an aluminum (Al) -containing compound, a silicon (Si) -containing compound, an alkali metal (Li, Na, K, Rb, Cs) -containing compound, and yttrium (Y). ), Lanthanum (La) -containing compound and europium (Eu) -containing compound were mixed using a solvent selected from ethanol, acetone, alcohol and water, and then dried to a high purity alumina dried at a temperature range of 50 ^o C to 200 ^o C. The heat treatment may be carried out in a boat at 800 ^o C to 1600 ^o C and 75% to 95%: 25% to 5% nitrogen or a mixed gas reducing atmosphere of argon and hydrogen.

In an embodiment, all of the above-mentioned compounds may be embodied as a single or a mixture of two or more selected from oxides, chlorides, hydroxides, nitrates, carbonates and superoxides of metals, and an active compound europium (Eu) containing compound Silver may be added in the range of 0.001 molar ratio to 0.5 molar ratio with respect to the amount of the alkali metal (Li, Na, K, Rb, Cs), aluminum (Al) and silicon (Si) containing compounds.

The light emitting device of the embodiment may be composed of a light emitting light source and a phosphor and may use at least the aluminum silicate-based phosphor or the aluminum silicate-based phosphor obtained by the manufacturing method.

The phosphor according to the embodiment is a (M _{1 - x} N _x ) ₄ (Si _{1 - y} Al _y ) ₈ O _{16 ± δ} as a parent and Eu ^{2 +} as an activator to reduce the process at a temperature of 1,200 ^o C or more It is produced through, and shows a light emission spectrum of a broad wavelength ranging from 400 nm to 800 nm, and has an excitation range of ultraviolet and blue regions.

According to this embodiment was able to produce the aluminum silicate-based phosphor of using the Eu ^{2 +} as the activator, it is possible to obtain a phosphor which emits light by ultraviolet and blue light-emitting diode excited by the energy source.

The phosphor of the embodiment may be coupled to ultraviolet and blue light emitting diodes and applied to backlights such as lighting, displays, and display devices.

1 shows a flowchart of a manufacturing method for obtaining a phosphor according to an embodiment.
2A and 2B illustrate absorption and emission spectra of phosphors obtained by exciting a phosphor obtained by changing a heat treatment temperature with ultraviolet rays of 395 nm in Examples.
Figure 3a and Figure 3b shows the emission spectrum of the 395 nm ultraviolet ray-excited luminance and wavelength changes according to the relative concentration of Al ^{3 +} and Si ^{+ 4} in the embodiment.
Figure 4 shows the emission spectrum of the phosphor according to the change of 0 ~ 0.06 molar ratio of the Eu ^{2 +} activator obtained in the example.
Figure 5 shows the XRD diffraction pattern according to the 0 ~ 0.06 molar ratio change of the Eu ^{2 +} activator obtained in the example.
6 illustrates a white emission spectrum of a light emitting device (a light emitting wavelength of 395 nm) manufactured by applying an aluminum silicate-based phosphor and a blue phosphor having a 445 nm emission wavelength according to an embodiment.

Hereinafter, (M _{1 - x} N _x ) ₄ (Si _{1 - y} Al _y ) ₈ O _{16 ± δ} according to one or more exemplary embodiments as a parent, Eu ^{2 +} is added as an active agent and then represented by the formula (1) The ultraviolet and blue excitation phosphor, the phosphor manufacturing method, and the white light emitting device including the phosphor will be described in more detail.

Formula 1

(M _{1 - x} N _x ) ₄ (Si _{1 - y} Al _y ) ₈ O _{16 ± δ} : Eu ^{2 +} _z

In the above formula, M and N are at least one element selected from the group of alkaline earth metals including Li, Na, K, Rb, Cs, etc., and 0 ≦ x ≦ 1, 0 <y <1, 0 <z ≦ 0.5 , δ is the change in the nonstoichiometric molar ratio of oxygen ions with the change of x and y values.

In the phosphor _{(M 1 - x N x)} 4 (Si 1 - y Al y) 8 O 16 ± δ is a crystal base material, wherein Eu ^{+ 2} is the active agent. A single or selected from manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), yttrium (Y) and lanthanum (La) in addition to the aluminum silicate-based phosphor containing only Eu ^{2 +} Two or more kinds of deactivator may be additionally included in a certain composition range, whereby the deactivator may affect the emission spectrum of the phosphor.

As a raw material of the phosphor according to the embodiment, aluminum nitrate (Al (NO ₃ ) ₃ ), aluminum oxide (Al ₂ O ₃ ), aluminum chloride (AlCl ₃ ), sodium nitrate (NaNO ₃ ), sodium chloride (NaCl ), Tetraorthosilicate (TEOS), meta-sodium silicate (Na ₂ SiO ₃ ), europium chloride (EuCl ₃ ), europium nitrate (Eu (NO ₃ ) ₃ ) can be used. In addition, if necessary, lithium nitrate (LiNO ₃ ), lithium chloride (LiCl), potassium nitrate (KNO ₃ ), potassium chloride (KCl), yttrium nitrate (Y (NO ₃ ) ₃ ), lanthanum nitrate ( Manganese (Mn), iron based on La (NO ₃ ) ₃ ), manganese chloride (MnCl ₂ ), manganese nitrate (Mn (NO ₃ ) ₂ ), and kapparate (Cu (NO ₃ ) ₂ ) It may be substituted with elements such as (Fe), cobalt (Co), nickel (Ni), copper (Cu), yttrium (Y), and lanthanum (La).

With the above raw material, an aluminum silicate-based phosphor can be produced by the following method. First, aluminum nitrate (Al (NO ₃ ) ₃ ), sodium nitrate (NaNO ₃ ), tetraolsosilicate (Tetraorthosilicate, TEOS) and europium chloride (EuCl ₃ ) are weighed according to the composition ratio of Chemical Formula 1. The raw materials are then mixed using one or more selected solvents from ethanol, acetone, alcohol and water. The raw materials mixed with the selected solvent are mixed to a uniform composition by using agitation and ultra sonic.

The mixture is sufficiently mixed using stirring and ultrasonic to obtain a uniform composition, and the mixture is dried in an oven until it is completely dried in a temperature range of 50 ^° C. to 200 ^° C. The dried mixture is placed in a high purity alumina crucible and heat treated in a reducing atmosphere of 5% / 95% hydrogen / nitrogen mixed gas. The heat treatment temperature is 1,200 ^° C. or more, and when the heat treatment temperature is less than 1200 ^° C., the emission intensity is reduced by the formation of a secondary phase other than the parent phase. Therefore, the heat treatment temperature is 1,200 ^o C or more and the heat treatment time is 3 hours or more.

If it does not form a reducing atmosphere, the europium (Eu) element cannot be reduced to ^divalent (Eu ^{2 +} ) and oxidized to exist as ^trivalent (Eu ^{3 +} ) to obtain a desired emission wavelength. Therefore, a reducing atmosphere must be formed. The hydrogen / nitrogen mixed gas uses a mixed gas mixed at a volume ratio of 2% to 25%. After heat treatment, the mixture was cooled to room temperature and sufficiently ground to obtain a powder phosphor.

The light emitting device according to the embodiment may include an aluminum silicate-based phosphor according to Chemical Formula 1 and a semiconductor LED chip. The aluminum silicate-based phosphor may be excited by light emitted from the light emitting diode chip.

As an example of the light emitting device, the light emitting diode may include a light source for emitting light, a substrate supporting the light source, and a molding member molded around the light source. Therefore, the light emitting diode may be configured by applying a coating phosphor composition for a light emitting device including an epoxy as an aluminum silicate-based phosphor and a molding member around the light emitting diode chip.

Example _{1: (Na 0 .75 K 0} .25) 4 (Si 0 .56 Al 0 .44) 8 O 16 .24: Eu 2 + 0.05 Preparation according to the heat treatment temperature of the phosphor.

_{(Na 0 .75 K 0 .25)} 4 (Si 0 .56 Al 0 .44) 8 O 16 .24: a phosphor having a composition of _{0. 05} Eu ^{2 +} phosphor was produced using the method above.

1 is a schematic flowchart for preparing an aluminum silicate-based phosphor of (M _{1 - x} N _x ) ₄ (Si _{1 - y} Al _y ) ₈ O _{16 ± δ} : Eu ^{2 +} _z composition shown in the Examples It is shown. In order to prepare the aluminum silicate-based phosphors presented in the examples, aluminum nitrate (Al (NO ₃ ) ₃ ), potassium nitrate (KNO ₃ ), sodium nitrate (NaNO ₃ ), tetraolsosilicate (TEOS) After weighing, europium chloride (EuCl ₃ ), it was dissolved in a solvent selected from ethanol, acetone, alcohol, and water, followed by stirring to obtain a uniform composition. The oven was completely dried at 120 ^° C. and heat-treated at 1,200 ^° C. to 1500 ^° C. for 3 hours. Here, 5% / 95% hydrogen / nitrogen mixed gas was used to maintain the reducing atmosphere. Absorption and emission spectra according to the heat treatment temperature of the aluminum silicate phosphor prepared by the above method are shown in FIGS. 2a and 2b.

Example _{2: (Na 0 .75 K 0} .25) 4 (Si 1 - y Al y) 8 O 16 _long: Eu ^{2 +} _0.05 (0 <y ≤ 0.6, -0.4 ≤ δ ≤ 0.24), PL spectra of aluminum silicate phosphors with relative concentrations of Al and Si.

The embodiment was Example 1 measuring the PL spectrum of the aluminum silicate phosphor according to the relative concentration of Al and Si in the phosphor made in accordance with, Al ^{3 +} concentration increases the maximum light emission intensity showed at y = 0.48, as Fig. 3a], It is shown in Fig. 3b that the main peak observed near 555 nm is gradually shifted to the long wavelength near 575 nm.

Example _{3: (Na 0 .75 K 0} .25) 4 (Si 0 .52 Al 0 .48) 8 O 16 .08: Eu 2 + z, (0 <z ≤ 0.06) aluminum silicate phosphor according to the molar concentration Emission spectrum measurement.

PL spectra were measured according to the concentration of Eu ^{2 +} phosphor made according to Example 1, Eu ^{2 +} concentration increases as a main peak was observed the emission intensity is increased in the vicinity of [4], and 555 nm, depending.

Example _{4: (Na 0 .75 K 0} .25) 4 (Si 0 .52 Al 0 .48) 8 O 16 .08: aluminum according to ^{Eu 2 + z, (0 <} z ≤ 0.06) Eu 2 + molar ratio XRD Diffraction Patterns of Silicate Phosphors.

[Figure 5] is _{(Na 0 .75 K 0 .25)} 4 (Si 0 .52 Al 0 .48) 8 O 16 .08 according to an embodiment: the Eu ^{2 +} z _z value of 0 to 0.06 mole ratio composition XRD diffraction pattern of the aluminum silicate phosphor made according to Example 1 while changing.

Example 5 FIG. 6 shows emission spectra of aluminum silicate-based phosphors applied to ultraviolet light emitting diodes. The embodiment provides a white LED device having excellent color purity and excellent color rendering (CRI ~ 90). The white LED device uniformly disperses the aluminum silicate-based phosphor and the blue phosphor prepared in the embodiment in an epoxy resin, and applies the chip to the chip portion of the light emitting diode, and causes the applied blue phosphor and the aluminum silicate-based phosphor to emit light under ultraviolet excitation. The used blue phosphor is selected to have a light emission wavelength region of 440 nm ~ 470 nm.

Features, structures, effects, and the like described in the above embodiments are included in at least one embodiment of the present invention, and are not necessarily limited to only one embodiment. Further, the features, structures, effects, and the like illustrated in the embodiments can be combined and modified by other persons having ordinary skill in the art to which the embodiments belong. Therefore, it should be understood that the present invention is not limited to these combinations and modifications.

In addition, the above description has been made with reference to the embodiments, which are merely exemplary and are not intended to limit the present invention. Those skilled in the art to which the present invention pertains will be illustrated above in the range without departing from the essential characteristics of the present embodiment. It will be appreciated that various modifications and applications are possible. For example, each component specifically shown in the embodiments can be modified and implemented. It is to be understood that all changes and modifications that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Claims (8)

Next, an aluminum silicate-based phosphor represented by [Formula];
[Chemical Formula]
(M _{1 - x} N _x ) ₄ (Si _{1 - y} Al _y ) ₈ O _{16 ± δ} : Eu ^{2 +} _z
In the above formula, M and N are at least one element selected from the group of alkaline earth metals including Li, Na, K, Rb, and Cs, and the concentration range is 0 ≦ x ≦ 1, 0 <y <1, 0 < z ≤ 0.5, δ is the change in the nonstoichiometric molar ratio of oxygen ions with the change of x and y values. The method of claim 1,
The size of the aluminum silicate-based phosphor is 0.5μm ~ 20μm phosphor. The method of claim 1,
The aluminum silicate-based phosphor has a light emission wavelength of 400 nm to 800 nm at an excitation wavelength of 250 nm to 500 nm. Forming a mixture using at least one solvent selected from ethanol, acetone, alcohol and water for the aluminum (Al) containing compound, the silica (Si) containing compound, the alkali metal containing compound, and the europium (Eu) containing compound;
Drying the mixture at a temperature ranging from 50 ^° C. to 200 ^° C .;
Heat-treating the dried mixture in a gas reducing atmosphere of nitrogen or argon and hydrogen at 800 ^° C. to 1600 ^° C. temperature and 75% to 95%: 25% to 5%;
Phosphor production method comprising a. 5. The method of claim 4,
The aluminum (Al) -containing compound, silica (Si) -containing compound, alkali metal-containing compound, and europium (Eu) -containing compound may be selected from the group consisting of one or two or more selected from oxides, chlorides, hydroxides, nitrates, carbonates and superoxides of metals. Method for producing a phosphor that is a mixture. The method according to claim 4 or 5,
The europium (Eu) -containing compound is a phosphor manufacturing method is added in an amount of 0.001 to 0.5 molar ratio with respect to the amount of the sodium (Na) containing compound, aluminum (Al) containing compound, silicon (Si) containing compound. 5. The method of claim 4,
Manganese (Mn), iron (Fe), chromium (Cr), calcium (Ca), zinc (Zn), cobalt (Co), nickel (Ni), copper (Cu) as an additive in addition to the europium (Eu) -containing compound ), A transition metal containing yttrium (Y), lanthanum (La), cerium (Ce), prasedium (Pr), neodymium (Nd), samarium (Sm), gadolium (Gd), terbium (Tb), Rare earth metals including dysprosium (Dy), erbium (Er), tulium (Tm), ytterbium (Yb) and lutetium (Lu), and metals including gallium (Ga), germanium (Ge) and indium (In) A method for producing a phosphor, wherein a single or two or more elements selected from the elements are added in an amount of 0.001 mol to 0.5 mol with respect to the amount of the aluminum (Al), sodium (Na), and silicon (Si) -containing compounds. A light emitting device comprising the phosphor according to any one of claims 1 to 3.

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