KR20090087580A - Yalo3:ce based fluorescent material and manufacturing method of the same - Google Patents

Abstract

An YAlO3:Ce based yellow fluorescent material is provided to ensure stability, high fluorescence efficiency, excellent light-emitting property in a red wavelength range, high color index and low color temperature. A method for manufacturing an YAlO3:Ce based fluorescent material comprises the steps of: (i) melting a precursor of Y, a precursor of Al and a precursor of Ce in solvent and heating the solution in a temperature range of 150~250 ‹C to form reaction precipitate, separating and drying the precipitate; (ii) heat-treating the dried resultant at 800~1100 ‹C to crystallize it; and (iii) reducing the Ce^4+ ion oxidized in the thermal processing step to Ce^3+ ion at 800~1300 ‹C.

Description

Yttrium aluminum perovskite (WIPI) -based phosphor and its manufacturing method {YAlO3: Ce based fluorescent material and manufacturing method of the same}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phosphor of a light emitting diode (LED), and more particularly, to a yellow phosphor for a white LED in which the color index, color temperature, and luminescence properties are remarkably improved compared to the related art, and a manufacturing method thereof.

A light emitting diode (LED) is a kind of semiconductor device that emits light by flowing a current through a compound such as gallium arsenide, and is used in flashing small lights, large electronic displays, and TV remote controls of various electronic devices. These LEDs consume only about 20% of incandescent bulbs and have a lifetime of 100,000 hours (100 times that of fluorescent lamps), which means that once installed, they require little replacement or maintenance. At present, the high-brightness LED that is attracting attention is a blue LED and a white LED, which is used as a backlight source of a mobile phone keypad and LCD liquid crystal display. In addition, white LEDs can be used as indoor lighting fixtures, produced by Nichia in Japan, HP in the US, and OSRAM in Germany. Compared with conventional light sources, white LEDs have a smaller power consumption, lifespan is semi-permanent, and there is no preheating time, so they have a fast response speed and emit no harmful waves such as ultraviolet rays. It is expected as an illumination light source.

To implement white LED that emits white light, a single-chip method of combining white or blue LED lamp with fluorescent material and white LED by combining two LEDs complementary to each other or combining several LED chips to obtain white There is a multichip method. When the white light is implemented by the latter method, there is a problem that it is difficult to generate desired white color due to dispersion of color tone or brightness of the light emitting device (LED), and when the light emitting devices are formed of different materials, the driving power of each light emitting device Since there is a need to apply a predetermined voltage to each element due to the difference, the driving circuit is complicated. In addition, since the light emitting device is a semiconductor light emitting device, there are problems such as color tone change due to different temperature characteristics and changes over time, and color tone may vary depending on the usage environment, or the light generated by each light emitting device may not be uniformly mixed. .

In order to solve the problems of the above-described multi-chip type white light implementation method, Japanese Patent Application Laid-Open No. 5-152609, Japanese Patent Laid-Open No. 7-99345, Japanese Patent Laid-Open No. 7-176794, etc. filed by Nichia in Japan As a white LED, a light emitting device capable of emitting blue light is disclosed, and a white LED realization technology capable of emitting white light by molding a resin that absorbs light emission and emits yellow light is emitted to the light emitting device.

In the conventional white LED, a garnet-based or silicate-based phosphor is used as a yellow phosphor that binds to a blue LED. The yellow-emitting YAG: Ce phosphor, which is a garnet-based phosphor, lacks fluorescence in a red wavelength region and is cold white (cold). white) Emits light. Therefore, the LED of the white light by the conventional garnet-based phosphor has a disadvantage that the color index is low and the color temperature is high. Therefore, there is a demand for the development of phosphors that have better luminous efficiency and excellent luminous characteristics in the red wavelength region than the garnet-based phosphors developed to date. Garnet-based and silicate-based phosphors, which are mainly used for the realization of white light, are limited in meeting these requirements, and there is an urgent need for the development of new phosphors containing a new crystal structure and a phosphor containing active ions. to be.

The object of the present invention is that the crystal structure is different from the conventional garnet- or silicate-based phosphor, which is stable and has a high fluorescence efficiency, and particularly excellent in luminescence in the red wavelength region, thereby achieving a cubic crystal having a high color index and low color temperature. It is to provide a yttrium aluminum perovskite (YA10 ₃ , YAP) -based yellow phosphor.

Another object of the present invention is a low temperature loss compared to the manufacturing method of the conventional garnet-based yellow phosphor, less heat loss, no need for a separate grinding process is simple, yttrium aluminum perovskite is excellent in the reduction efficiency of active ions It is to provide a method for producing a YAP yellow phosphor.

In order to achieve the above object, the present invention provides a yttrium aluminum perovskite-based (YAlO ₃ , YAP) -based phosphor, characterized in that the yellow phosphor has a crystal phase occupying 60% or more of the total compound.

Here, the yttrium aluminum perovskite-based phosphor is preferably a material represented by the following <Formula 1>.

<Formula 1>

(Y _{1 - x} Re _x ) (Al _{1 - y} Tr _y ) O ₃ : Ce ^{3 +} , M _z

Where Re is any one selected from the group of rare earth elements comprising Gd, La, Sm, Tb, Pr, Dy, Eu, and Tr is a transition element group comprising Ga, In, Sc, Cr M is any one selected from the group consisting of Tb, Sm, Dy and Cr as rare earth elements or transition elements emitting fluorescence in the yellow region and the red region, and 0 <x <1, 0.001 <y <0.2, 0.001 <z <0.1.)

In this case, the fluorescence absorption wavelength of the yttrium aluminum perovskite-based phosphor is in the range of 420 to 500 nm, and the peak wavelength of the fluorescence absorption is in the range of 430 to 495 nm.

It is preferable that the yttrium aluminum perovskite-based phosphor particles have a size in the range of 20 to 70 nm.

When the yttrium aluminum perovskite-based phosphor is excited with light of 470 nm, the light emitting region of fluorescence reaches a wavelength region of 470 to 700 nm, and the peak of the light emitting region of fluorescence is within a range of 500 to 650 nm.

According to another aspect of the present invention, there is provided a white light emitting LED formed using the yttrium aluminum perovskite-based phosphor and a blue LED.

The blue LED preferably has a wavelength of 450 to 470 nm of an emission peak.

According to another aspect of the invention, in the method for producing a yttrium aluminum perovskite (YAlO ₃ : Ce, YAP) -based phosphor, (a) Y precursor, Al precursor and Ce precursor are dissolved in a solvent and 150 Reaction step of the precursor to form a reaction precipitate by heating in the temperature range of ~ 250 ℃ and to separate the precipitate to dry, (b) heat treatment step of crystallizing the dried reactant by heat treatment in the temperature range of 800 ~ 1100 ℃ and ( c) Yttrium aluminum perovskite system, characterized in that it comprises a reduction treatment step of reducing the Ce ^{4 +} ions oxidized in the thermal treatment step to Ce ^{3 +} ions in the temperature range of 800 ~ 1300 ℃ (YAlO ₃ : Ce, YAP) type phosphor is provided.

Here, the precursor of Y is selected from yttrium inorganic salts or yttrium organic salts, the precursor of Al is selected from aluminum alkoxides, the precursor of Ce is preferably selected from cerium inorganic salts or cerium organic salts.

According to another aspect of the invention, the formula (Y _{1 - x} Re _x ) (Al _{1 - y} Tr _y ) O ₃ : Ce ^{3 +,} A method for producing a yttrium aluminum perovskite teugye phosphor represented by M _z, (a) at least one selected from the group consisting of a precursor of Y and Re precursors, and at least selected from the precursor of Al and Tr Reaction step of one or more precursors and precursors for dissolving the precursor of Ce in a solvent and heating at a temperature range of 150 ~ 250 ℃ to form a reaction precipitate, and then separating and drying the precipitate, (b) 800 ~ 1100 A heat treatment step of crystallizing by heat treatment in the temperature range of ℃ and (c) a reduction treatment step of reducing the Ce ^{4 +} ions oxidized in the heat treatment step to Ce ^{3 +} ions in the temperature range of 800 ~ 1300 ℃, In the above formula, Re is any one selected from the group of rare earth elements composed of Gd, La, Sm, Tb, Pr, Dy, Eu, and Tr is a transition element including Ga, In, Sc, Cr. M is any one selected from the group, M is a rare earth element or a transition element that emits fluorescence in the yellow region and the red region, any one selected from the group consisting of Tb, Sm, Dy, Cr, 0 <x <1, Provided is a method for producing an yttrium aluminum perovskite-based phosphor, characterized in that 0.001 <y <0.2, 0.001 <z <0.1.

Here, the precursor of Y is selected from yttrium inorganic salts or yttrium organic salt, the precursor of Al is selected from aluminum alkoxides, the precursor of Ce is selected from cerium inorganic salts or cerium organic salts, the precursor of Re Gd, La, Sm, Tb, Pr, Dy, Eu is selected from any one of the inorganic salts or organic salts selected from the group consisting of, the precursor of Tr including Ga, In, Sc, Cr It is selected from any one inorganic salt or organic salt selected from the transition element group is composed, the precursor of M is any inorganic salt or organic selected from the rare earth element or transition element group that emits fluorescence in the yellow region and red region It is preferred to be selected from salts.

The yttrium aluminum perovskite (YAP) -based phosphor of the present invention exhibits a high absorption peak in the blue and green regions, and is superior to the conventional garnet-based phosphor in the yellow and red wavelength regions. In addition, since the light emission luminance is superior to the conventional garnet-based (YAG) phosphor, when used in combination with a blue light emitting LED, the luminous efficiency is very excellent. In addition, the cubic YAlO ₃ : Ce-based phosphor of the present invention has excellent fluorescence efficiency in the red wavelength region compared to the garnet-based phosphor, so it is possible to produce a white light emitting LED having excellent color index and low color temperature by combining with a blue light emitting LED. Has the advantage.

According to the manufacturing method of the yttrium aluminum perovskite (YAP) -based phosphor of the present invention, since it is possible to manufacture in a relatively low temperature region compared to the manufacturing process of the conventional garnet-based phosphor, the energy efficiency is excellent, and the crystal of the phosphor in nanometer size Since this is generated, unlike the fluorescent material generated in the unit of the conventional micrometer, there is no need for a separate grinding process, which has the advantage of shortening the number of processes.

Hereinafter, with reference to the accompanying drawings, a cubic yttrium aluminum perovskite (YA10 ₃ , YAP) -based phosphor for a white LED of the present invention and a manufacturing method thereof will be described in detail.

The yellow phosphor according to the present invention is a cubic yttrium aluminum perovskite-based phosphor represented by Formula 1 below, and has an aluminum perovskite-based crystal structure whose cubic structure or cubic system occupies 60% or more of the phosphor compound. It is a phosphor of chemical composition.

<Formula 1>

(Y _{1 - x} Re _x ) (Al _{1 - y} Tr _y ) O ₃ : Ce ^{3 +} , Mz

Here, Re is rare earth element such as Gd, La, Sm, Tb, Pr, Dy, Eu, Tr is transition element such as Ga, In, Sc, Cr, M is yellow wavelength such as Tb, Sm, Dy, Cr Rare earth elements or transition elements that emit fluorescence in the region and in the red wavelength region are shown. Also, x, y, and z have ranges of 0 <x <1, 0.001 <y <0.2, and 0.001 <z <0.1, respectively.

Yttrium aluminum perovskite (YAlO ₃ , YAP) has three crystal structures: hexagonal, cubic, and rectangular, among which the rectangular system is a safe crystalline phase, and the hexagonal and cubic systems are known as metastable. It is found in mixed form with other crystalline phases (Y ₂ O ₃ , Y ₃ Al ₅ O ₁₂ , Y ₄ Al ₂ O ₉ ). The rectangular YAlO ₃ : Ce is well known to emit ultraviolet fluorescence with a peak of 380 nm when irradiated with x-rays or gamma rays. It is mainly used as a detector for x-rays and gamma rays as a crystal. Doing. The hexagonal and cubic YAlO ₃ are metastable crystalline phases and appear in nanoscale particles. This is one of the size effects in nanoscale materials. As the particle size decreases to nanometers, the symmetry of the crystal structure increases.

In the three crystal structures of YAlO ₃ , the symmetry of the hexagonal system is the largest, and the symmetry decreases in the order of the cubic system and the rectangular system. According to the size effect, it is expected that the particle size of the hexagonal system with the greatest symmetry will be the smallest, and the particle size will increase in the order of cubic system and rectangular system.

The cubic YAlO ₃ : Ce powder is white in color and the cubic YAlO ₃ : Ce powder is yellow in color. The cubic YAlO ₃ : Ce phosphor of the present invention emits orange fluorescence but is called yellow phosphor because its reflection color is yellow.

The phosphor according to the present invention is a cubic system or a YAlO ₃ cubic system occupies 60% or more of the compound It is a phosphor of the system, and the crystal phases of hexagonal and rectangular systems may be mixed depending on the amount of the rare earth metal corresponding to Re of the general formula (1). In the present invention, YAlO _{3 which} is a crystal phase of a cubic system Ce ^{3 +} was added to the active ions to emit fluorescence in the yellow wavelength region, and activators such as Tb, Sm, Dy, and Cr were simultaneously added to increase the luminescence efficiency of the fluorescence and to enhance the fluorescence in the red region.

YAG is a crystal of a cubic system having a lattice constant of 12.00 GPa, and a lattice constant of YAlO ₃ of the present invention is 12.10 GPa. In the crystal structure of YAG, the Y element forms the dodecahedron structure of YO ₈ having eight oxygen atoms at the closest distance, and the added active ion Ce is also substituted at the position of Y atom. On the other hand, in the crystal structure of the cubic YAlO ₃ of the present invention, the Y atom forms the structure of YO ₁₂ , and the added active ion Ce is substituted in place of the Y atom. The cubic YAlO ₃ crystal structure is similar to YAG, but the number of coordinated oxygen atoms is different. Accordingly, the spectroscopic properties of Ce, which are related to the size of the crystal field and the symmetry of the crystal field, are also changed. Conventional YAG: Ce-based fluorescence absorption peak is 470 nm and the fluorescence wavelength is 530 ~ 550 nm, the fluorescence absorption wavelength of YAlO ₃ : Ce of the present invention is in the region of 420 ~ 500 nm, the fluorescence absorption peak is 430 ~ 495 nm The fluorescence wavelength is 560 nm or more, and the stokes shift, which is a difference between the absorption wavelength and the emission wavelength of the phosphor, is larger than that of conventional YAG: Ce. Fluorescence wavelength by a large Stoke shift of Ce is YAG:: YAlO ₃ as compared to Ce relatively been moved to the red wavelength region, such Stokes shift is relatively large cubic YAlO ₃ as: Using the fluorescent substance of Ce color index is high White LEDs can be manufactured.

As described above, the tetragonal system is a stable crystal phase in YAlO ₃ , and the crystal phases of the hexagonal system and the cubic system are metastable phases exhibited by the size effect. The YAlO ₃ crystal phase of the cubic system is a metastable crystal structure appearing mixed with other crystal phases, and a synthesis method in which the YAlO ₃ of the cubic system is independently present has not been known until now. However, in the present invention was to be able to synthesize these cubic YAlO ₃ by the method of manufacturing the phosphor will be described later, in the end YAlO ₃ by the addition of Ce ^{+ 3:} able to provide the nano-Ce-based phosphors. Phosphor of the present invention is excellent in fluorescence efficiency compared to the conventional YAG: Ce phosphor, and excellent in the fluorescence characteristics of the red wavelength region. The superiority of the YAlO ₃ : Ce-based nanophosphor of the present invention will be described later with reference to the drawings.

The manufacturing process of the yttrium aluminum perovskite (YAlO ₃ , YAP) -based yellow phosphor of the present invention is largely composed of three steps: (1) reaction of precursor, (2) heat treatment of reactant, and (3) reduction treatment. The detailed process is as follows.

(1) Reaction step of precursor

In order to prepare the YAlO ₃ : Ce phosphor of the present invention, Y precursor, Al alkoxide precursor, and Ce precursor are uniformly dissolved in alcohol, and heated in a high pressure reactor at 150 to 250 ° C. The molar ratio of the precursor of Y and the precursor of Al is 1: 1, which is a chemical quantitative ratio, and the molar ratio between the precursors can be changed from 1: 0.95 to 1: 1.1 according to the type or amount of the element to be substituted. When the concentration of the precursor to the alcohol solvent is less than 0.1 M (molar concentration), the fluorescence efficiency of the synthesized reactant is high, and when the concentration of the precursor is greater than 0.2 M, it was confirmed that the reactants are not uniformly mixed.

Most metal salts have increased solubility as the solvent temperature increases. In the precursor reaction of the present invention, the precursor is dissolved and mixed at a temperature of 150 to 250 ° C., and the experimental results confirm that the precursor is mixed very uniformly in this temperature range. It became. In the subsequent heat treatment step, the crystallization temperature of YAlO ₃ by heat treatment is very sensitive to the mixing homogeneity of the precursors.

Since the above reaction temperature in the reaction process of the precursor is higher than the vaporization point of the general alcohol solvent, the solvent shows a pressure higher than the atmospheric pressure at the reaction temperature. In order to withstand such high pressure, a high pressure reactor made of a metal, not a vitreous device, The reaction should be carried out using an autoclave. In addition, in order to prevent the risk of explosion due to the high pressure of the solvent generated at the reaction temperature, it is preferable to reduce the pressure by reducing the amount of the solvent to fill the high-pressure reactor.

In this precursor reaction step, Al alkoxide and precursors such as Y and Ce react, hydrate and decompose to precipitate. During the reaction process, the solution is continuously mixed to make the reactants uniform. The precipitate produced after the reaction is centrifuged and dried in a drying furnace. The temperature of the drying furnace is preferably maintained at 40 ~ 100 ℃, the drying temperature may vary depending on the type of solvent.

As a precursor of Y, yttrium inorganic salts such as yttrium acetate, yttrium nitrate, yttrium halide salt, and yttrium salts dissolved or mixed in alcohol such as yttrium acetylacetonate and yttrium organic salt such as yttrium 2 ethylhexanoate can be used. Precursors such as Tb, Ce, La, Dy, Pr, Sm, Ga, Cr and the like may also be selected from inorganic and organic salts such as acetates, nitrates and halogenated salts. As the precursor of Al, aluminum alkoxide which is dissolved or mixed in alcohol such as aluminum methoxide, aluminum ethoxide, aluminum propoxide, aluminum butoxide and the like is used. As the solvent used in the reaction, an organic solvent capable of dissolving alcohols such as metalol, ethanol, 1-propanol, butanol, 2-methoxyethanol and the aforementioned precursor may be selected.

(2) heat treatment step of the reactants

In this step, the reaction precipitate generated through the reaction of the precursor is crystallized by heat treatment (calcination) and the organic matter remaining in the reaction is oxidized and removed. First, the dried precipitated powder is placed in a crucible and heat treated. This heat treatment process is carried out in the temperature range of 800 ~ 1100 ℃, maintaining the air atmosphere. The reactant dried in the previous step is crystallized in this heat treatment process, and the heat-treated powder has a cubic crystal phase. If the precursors are not uniformly mixed and reacted during the reaction, hexagonal and rectangular YAlO ₃ crystal phases may be precipitated, and Y ₃ Al ₅ O ₁₂ (YAG), Y ₄ Al ₂ O ₉ (YAM), Y ₂ O ₃ lights precipitate. In this way, when crystalline phases other than the cubic system are precipitated, the fluorescence efficiency of YAlO ₃ : Ce decreases rapidly. In addition, when the heat treatment temperature is lower than 800 ° C., the cubic YAlO ₃ is not generated and is near to an amorphous state. When the heat treatment temperature is higher than 1100 ° C., the crystal phases of YAG, YAM, Y ₂ O _3, and the like, and the crystal phases of YAlO ₃ of hexagonal and rectangular system, Is generated.

(3) reduction treatment step

In the reduction step, Ce _{4 +} ions oxidized during the heat treatment are reduced to Ce _{3 +} ions. After the heat treatment, the phosphor is white or yellowish and is reduced in a mixed gas atmosphere mixed with hydrogen. Reduction treatment can be carried out in the temperature range of 800 ~ 1300 ℃, the hydrogen mixture concentration of the mixed gas can be 0 ~ 100%. In the present invention, since the crystal of the phosphor is produced in the nanometer size, no separate grinding process is required, but if necessary, the reduced yellow phosphor may be used by grinding with a mortar or ball mill.

Through the above steps, the yttrium aluminum perovskite-based (YAP) yellow phosphor of the present invention is obtained. In the conventional solid phase reaction, YAG is synthesized at a temperature of 1500 ° C. However, the cubic YAlO ₃ of the present invention can be synthesized even at a relatively low temperature of 800 ° C., thus saving energy required for the synthesis of phosphors. . In order to increase the fluorescence efficiency of Ce ^{3 +} , a process of reducing Ce ^{4 +} generated in the synthesis process is necessary. The conventional YAG: Ce phosphor has to be reduced at a temperature of 1500 ° C. However, the cubic YAlO ₃ : Ce phosphor is also excellent in fluorescence characteristics of Ce ^{3 +} when reduced in the temperature range of 800 ~ 1300 ℃ excellent energy saving effect compared to the conventional YAG: Ce manufacturing process in the reduction process.

Conventional YAG: Ce phosphors have a fluorescence spectrum with a peak of 550 nm. The light emission of white LEDs produced by the SMD method using YAG: Ce phosphors and 470 nm blue LEDs is high in color temperature and low in color index. It is called cold white. To overcome this problem, it is required to develop a phosphor having excellent fluorescence in the red wavelength region. Conventional garnet-based phosphors have synthesized phosphors substituted with Gd, Tb, and La in place of Y atoms to increase the fluorescence efficiency of the red region. However, in this method, the fluorescence of the red region is relatively excellent. The efficiency was reduced, resulting in a failure to increase the color index.

Conventional YAG forms a very stable crystal phase, so even if the Gd, Tb, La, etc. of different sizes are substituted in the Y atom, the change in the crystal field acting on Ce ^{3 +} ions is insignificant. There is a problem in that the fluorescence of Ce ³⁺ ions due to the substitution of R ⁴ is rather quenched, resulting in a decrease in the overall fluorescence efficiency. However, the metastable crystalline phase cubic YAlO ₃ of the present invention, Gd, Tb, when substituted for La deformation of the crystal structure in accordance with the matrix and cation exchange is largely appears, compared with YAG changed sheets determined acting on the active ion Ce ^{3 +} Ce The energy level of ^{3 +} ions is changed so that the fluorescence of Ce ^{3 +} ions moves to the red wavelength region.

1 is a graph comparing the X-ray diffraction pattern of the conventional YAG and the cubic YAlO ₃ of the present invention. (a) is JCPDS 33-0040 of conventional YAG, (b) is diffraction pattern of YAG nanopowder, (c) is JCPDS 38-0222 of cubic YAlO ₃ , and (d) is YAlO ₃ nano of the present invention X-ray diffraction pattern of the powder. The lattice constant of YAG is 12.00 GPa, and the lattice constant of cubic YAlO ₃ is 12.10 GPa. As shown, the x-ray diffraction patterns of the two nanopowders with the lattice constants similar to those of the same crystal structure look almost similar, but as the diffraction angle increases, the diffraction peaks of the two materials are greatly shifted. The red dotted line is the auxiliary line drawn to compare the diffraction peak angle between the two materials.

2 is an EDS analysis spectrum measured by SEM of the conventional YAG and the cubic YAlO ₃ of the present invention. The graph of Figure 2 shows a comparison according to the component ratio of the conventional YAG and YAlO ₃ of the present invention, according to the exact chemical composition, the ratio of Y and Al in Y ₃ Al ₅ O ₁₂ is 3: 5 = 1: 1.67, The ratio of Y and Al in YAlO ₃ is 1: 1. (a) is the EDS spectrum of YAG, and (b) is the EDS spectrum of YAlO ₃ . In the figure, the Kα emission line of Al and the Lα, Lβ emission line of Y were measured, respectively, and the ratio of chemical amounts of Al and Y was proportional to the area ratio of AlKα, YLα, and YLβ signals.

3 is an electron microscope (FESEM) photograph of the YAlO _3- based nanopowder according to the present invention. (a) is a YAlO _3: Ce is a FESEM picture of the nano powder, (b) Y is _{0 .95 0 .05} AlO Gd _3: a photograph of the nano-Ce powder, (c) is Y _{0 .95 0 .05} Sm AlO ₃ : Photograph of Ce nanopowder. Each YAlO ₃ particle is almost spherical, the particle size ranges from 20 to 70 nm, and the average size is about 40 nm, indicating that it is a uniform particle with a small dispersion in size.

4 is a graph showing the fluorescence excitation (absorption) spectrum of YAlO ₃ : Ce according to the present invention. The peaks at 340 nm and 470 nm are due to the absorption of Ce ^{3 +} ions, and the absorption by the parent YAlO ₃ is omitted in the figure. The full width at half maximum (FWHM) of the absorption band with a peak at 470 nm reaches about 50 nm.

5 is a graph comparing the fluorescence spectrum of the conventional YAG: Ce and YAlO ₃ : Ce of the present invention. Excited with 470 nm blue LED emission and measured with a spectrometer equipped with an array CCD sensor. The fluorescence of (a) YAlO ₃ : Ce has a peak around 563 nm and the fluorescence is stronger in the red wavelength region than the conventional (b) YAG: Ce having a fluorescence peak of 553 nm. Therefore, when the white LED is manufactured using the YAlO ₃ : Ce phosphor of the present invention, the color index may be increased and the color temperature may be lower than that of the conventional white LED. In the fluorescence spectrum, the area is proportional to the relative intensity of fluorescence, and the fluorescence intensity of YAlO ₃ : Ce calculated by area is about 1.07 times that of YAG: Ce.

6 is a graph illustrating x-ray diffraction patterns of Y _{1 - x} Gd _x AlO ₃ : Ce-based nanopowders according to the present invention. (a) Y is _{0 .95 0 .05} Gd ₃ AlO: and Ce, (b) is _{Y 0 .8 Gd 0 .2 AO 3} : is Ce, (c) is Y _{0 .6} Gd _{0 .4} AlO ₃ : is Ce, (d) is _{Y 0 .2 Gd 0 .8 AlO 3} : is Ce, (e) is a GdAlO _3: is Ce. The chemical composition of the five substances is the same as that of perovskite (ABO ₃ ), and each of the crystal structures shows that (a), (b), (c), and (d) are cubic, and most of (e) It is a cubic system and only a part is a cubic system. Arrows show the diffraction peaks of rectangular perovskite. As shown in the graph, as the amount of substituted Gd increases, the diffraction angle of the cubic system decreases, which is the result of replacing Gd having a large ion radius at the Y-position of YAlO ₃ . The lattice constants are (a) 12.041 Å, (b) 12.044 Å, (c) 12.068 Å, and (d) 12.098 각각, respectively. The lattice constants of the rectangular perovskite (e) are a = 5.24 Å, b = 5.281 Å, c = 7.442 Å, and are almost the same as in JCPDS 71-1597.

Figure 7 is a graph showing the fluorescence spectrum of Y _{1 - x} Gd _x AlO ₃ : Ce-based phosphor according to the present invention. It can be seen that when the amount of Gd added increases, the fluorescence of Ce moves to a long wavelength region, and the fluorescence near 620 nm increases. In the existing YAG: Ce phosphor, when Gd is substituted at the Y site, the wavelength of fluorescence shifts to the red region, but the fluorescence efficiency decreases. In the phosphor of cubic Y _1-x Gd _x AlO ₃ : Ce of the present invention, the fluorescence peak shifted to 620 nm with little decrease in fluorescence efficiency even when Gd was substituted by 25%. This fluorescence is not shown in the existing YAG: Ce phosphors, but is a characteristic of the cubic perovskite Y _{1 - x} Gd _x AlO ₃ : Ce of the present invention. In YAG: Ce, a small structure of CeO ₈ dedecahedron is formed with eight times the oxygen around Ce ions, whereas in YAlO ₃ : Ce phosphor, a small structure of CeO ₁₂ is formed with ₁₂ oxygen atoms around Ce ions. do. By using Y _1-x Gd _x AlO ₃ : Ce phosphors having such fluorescence characteristics, white LEDs having a high color index can be manufactured and energy conversion efficiency is not reduced. The area in the fluorescence spectrum is proportional to the relative intensity of the fluorescence. The fluorescence intensity of (b) calculated by area was about 1.04 times that of (a), and (c) about 1.09 times that of (a). The wavelengths of the fluorescence peaks of (b) and (c) are 560 nm and 565 nm, respectively.

8 is an x-ray diffraction pattern graph of Y _{1 - x} Sm _x AlO ₃ -based nanopowders according to the present invention. (a) is YAlO ₃ : Ce, (b) is Y _0.95 Sm _0.05 AlO ₃ : Ce, (c) is Y _0.8 Sm _0.2 AlO ₃ : Ce, and (d) is SmAlO ₃ : Ce. The quantitative ratio of the chemical composition of the four substances is the same as that of perovskite (ABO ₃ ), and each of the crystal structures (a), (b) and (c) is a cubic system and (d) is a cubic system. The lattice constants are (a) a = 12.039Å, (b) a = 12.039Å, (c) a = 12.059Å, (d) a = 5.293Å, b = 5.290Å, c = 13.006Å, respectively. JCPDS 46- Almost identical to 0395.

Figure 9 is one embodiment Y _{0 .95 0 .05} Sm AlO ₃ of the present invention: a graph showing the fluorescence spectra of Ce. It was excited with light of 470 nm and measured with an array CCD spectrometer. Peak around 625nm is a phosphor that Sm ^{3 +} ions are released. Sm can be substituted for YAlO ₃ : Ce to increase fluorescence in the red region.

Figure 10 is another embodiment of the invention Y _{0 .97 0 .03} Tb ₃ AlO: a graph showing the fluorescence spectra of Ce. A small amount of Tb added to YAlO ₃ : Ce increases yellow fluorescence.

Figure 11 is another embodiment of the invention Y _{0 .97 0 .03} AlO Dy _3: a graph showing the fluorescence spectra of Ce. When a small amount of Dy is added to YAlO ₃ : Ce, yellow fluorescence is reduced.

12 is a graph showing the fluorescence spectrum of YAlO ₃ : Ce, Cr according to the present invention. The peak around 700 nm is due to Cr ^{3 +} ions and the transition from the ² E energy level to the ⁴ A ₂ energy level.

Figure 13 is another embodiment YAl _{0 .97} Ga _{0 .03} O ₃ of the present invention: a graph showing the fluorescence spectra of Ce. When a small amount of Ga is added to YAlO ₃ : Ce, yellow fluorescence increases.

Figure 14 is another embodiment Y _{0 .95} Gd _{0 .05} AlO ₃ of the present invention: a graph showing the fluorescence spectra of Ce, Tb. Gd was substituted for YAlO ₃ : Ce and Tb was added.

FIG. 15 is a color coordinate of a blue light emitting diode of 470 nm and a white light emitting LED manufactured by SMD using a cubic YAlO ₃ : Ce phosphor of the present invention. The values of color coordinates are x = 0.34 and Y = 0.36.

Looking at the graph of the above drawings, the yttrium aluminum perovskite-based phosphor of the present invention, when excited with light of 470 nm, the emission region of fluorescence reaches a wavelength region of 470 ~ 700 nm, the peak of the emission region of fluorescence is 500 It can be seen that it is in the range of 650 nm.

The yttrium aluminum perovskite-based phosphor of the present invention has a higher fluorescence efficiency than the conventional garnet-based phosphor in implementing a white LED, particularly excellent light emission characteristics in the red wavelength region, and thus has a high color index and low color temperature. It is possible to replace the garnet-based phosphor of, and as a light emitting means to replace the conventional lighting fixtures, it will be said that it is very widely applicable in all industrial fields including electric, electronic device field and lighting fixtures.

1 is a graph comparing the X-ray diffraction pattern of the conventional YAG and the cubic YAlO ₃ of the present invention.

2 is an EDS analysis spectrum of a conventional YAG and the cubic system YAlO ₃ of the present invention measured by SEM.

Figure 3 is an electron microscope (FESEM) photograph of the YAlO _3- based nanopowder according to the present invention.

Figure 4 is a graph showing the fluorescence excitation spectrum of YAlO ₃ : Ce according to the present invention.

5 is a graph comparing the fluorescence spectrum of the conventional YAG: Ce and YAlO ₃ : Ce of the present invention.

6 is a graph illustrating an x-ray diffraction pattern of Y _{1 - x} Gd _x AlO ₃ : Ce-based nanopowders according to the present invention.

7 is a graph showing the fluorescence spectrum of Y _{1 - x} Gd _x AlO ₃ : Ce-based phosphors according to the present invention.

8 is an X-ray diffraction pattern graph of Y _{1 - x} Sm _x AlO ₃ -based nanopowders according to the present invention.

Figure 9 is one embodiment Y _{0 .95 0 .05} Sm AlO ₃ of the present invention: a graph showing the fluorescence spectra of Ce.

Figure 10 is another embodiment Y _{0 .97} Tb _{0 .03} AlO ₃ of the present invention: a graph showing the fluorescence spectra of Ce.

Figure 11 is another embodiment Y _{0 .97} Dy _{0 .03} AlO ₃ of the present invention: a graph showing the fluorescence spectra of Ce.

12 is a graph showing the fluorescence spectrum of YAlO ₃ : Ce, Cr according to the present invention.

Figure 13 is another embodiment YAl _{0 .97} Ga _{0 .03} O ₃ of the present invention: a graph showing the fluorescence spectra of Ce.

Figure 14 is another embodiment Y _{0 .95} Gd _{0 .05} AlO ₃ of the present invention: a graph showing the fluorescence spectra of Ce, Tb.

FIG. 15 is a color coordinate of a white LED having a 470 nm blue LED and a cubic YAlO ₃ : Ce phosphor of the present invention prepared by the SMD method. FIG.

Claims (11)

An yttrium aluminum perovskite-based (YAlO ₃ , YAP) -based phosphor, wherein the yellow phosphor has a crystal phase in which the cubic system occupies 60% or more of the entire compound. The method of claim 1, The yttrium aluminum perovskite-based phosphor is a yttrium aluminum perovskite-based phosphor, characterized in that the material represented by the following formula (1). <Formula 1> (Y _{1 - x} Re _x ) (Al _{1 - y} Tr _y ) O ₃ : Ce ^{3 +} , M _z Where Re is any one selected from the group of rare earth elements comprising Gd, La, Sm, Tb, Pr, Dy, Eu, and Tr is selected from the group of transition elements comprising Ga, In, Sc, Cr M is any one selected from the group consisting of Tb, Sm, Dy and Cr as rare earth elements or transition elements emitting fluorescence in the yellow region and the red region, and 0 <x <1, 0.001 < y <0.2, 0.001 <z <0.1.) The method according to claim 1 or 2, An yttrium aluminum perovskite-based phosphor, wherein the fluorescence absorption wavelength is in the range of 420 to 500 nm and the peak wavelength of the fluorescence absorption is in the range of 430 to 495 nm. The method according to claim 1 or 2, Yttrium aluminum perovskite-based phosphor, characterized in that the size of the phosphor particles is 20 ~ 70 nm. The method according to claim 1 or 2, An yttrium aluminum perovskite-based phosphor, characterized in that the fluorescence emission region reaches a wavelength region of 470-700 nm when excited with light of 470 nm, and the peak of the fluorescence emission region is in the range of 500-650 nm. A white light emitting LED formed using the yttrium aluminum perovskite phosphor of claim 1 or 2 and a blue LED. The method of claim 6, The blue LED is a white light emitting LED, characterized in that the wavelength of the emission peak is 450 ~ 470 nm. In the method for producing a yttrium aluminum perovskite (YAlO ₃ : Ce, YAP) -based phosphor, (a) a reaction step of dissolving a precursor of Y, a precursor of Al and a precursor of Ce in a solvent and heating at a temperature in a range of 150 to 250 ° C. to form a reaction precipitate, followed by separating and drying the precipitate; (b) a heat treatment step of crystallizing the dried reactant by heat treatment at a temperature in the range of 800 to 1100 ° C .; And (c) a reduction treatment step of reducing the Ce ^{4 +} ions oxidized in the heat treatment step to Ce ³⁺ ions in a temperature range of 800 to 1300 ° C. A method for producing a yttrium aluminum perovskite-based (YAlO ₃ : Ce, YAP) -based phosphor, characterized in that it comprises a. The method of claim 8, The precursor of Y is selected from yttrium inorganic salts or yttrium organic salts, The precursor of Al is selected from aluminum alkoxides, The precursor of Ce is a method for producing a yttrium aluminum perovskite-based phosphor, characterized in that selected from cerium inorganic salts or cerium organic salts. Formula (Y _{1 - x} Re _x ) (Al _{1 - y} Tr _y ) O ₃ A Ce ^{+ 3,} the manufacturing method of yttrium aluminum perovskite teugye phosphor represented by M _z,: (a) dissolving at least one precursor selected from precursors of Y and Re, at least one precursor selected from precursors of Al and Tr, and a precursor of Ce in a solvent and heating at a temperature ranging from 150 to 250 ° C. A reaction step of forming a reaction precipitate and then separating the precipitate and drying the precursor; (b) a heat treatment step of crystallizing the dried reactant by heat treatment at a temperature in the range of 800 to 1100 ° C .; And (c) jidoe comprises a reduction treatment step of reducing the Ce ³⁺ ions to the Ce ^{+ 4} ion oxidation in the thermal treatment step in a temperature range of 800 ~ 1300 ℃, In the above formula, Re is any one selected from the group of rare earth elements including Gd, La, Sm, Tb, Pr, Dy, Eu, and Tr is selected from the group of transition elements including Ga, In, Sc, and Cr. M is any one selected from the group consisting of Tb, Sm, Dy and Cr as rare earth elements or transition elements emitting fluorescence in the yellow region and the red region, and 0 <x <1, 0.001 < y <0.2, 0.001 <z <0.1 A method for producing a yttrium aluminum perovskite phosphor, characterized in that the. The method of claim 10, The precursor of Y is selected from yttrium inorganic salts or yttrium organic salts, The precursor of Al is selected from aluminum alkoxides, The precursor of Ce is selected from cerium inorganic salts or cerium organic salts, The precursor of Re is selected from any one of inorganic or organic salts selected from the group of rare earth elements comprising Gd, La, Sm, Tb, Pr, Dy, Eu, The precursor of Tr is selected from any one inorganic salt or organic salt selected from the group of transition elements including Ga, In, Sc, Cr, The precursor of M is yttrium aluminum perovskite-based phosphor manufacturing method characterized in that it is selected from any one of an inorganic salt or an organic salt selected from the rare earth element or transition element group that emits fluorescence in the yellow region and the red region.

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