KR100844579B1 - The process of fluorescent substance based on ygd2o3:eu using solvent evaporation method - Google Patents

Abstract

A method for preparing a red light emitting phosphor by using a solvent evaporation process is provided to obtain an oxide phosphor useful for a display device, having a uniform shape and small size and showing excellent light emitting characteristics via a simple and cost-efficient process. A method for preparing a red light emitting phosphor by using a solvent evaporation process comprises the steps of: (i) mixing yttrium chloride hydrate(YCl3.6H2O) with gadolinium chloride hydrate(GdCl3.6H2O) and dissolving the mixture in distilled water to provide a precursor solution; (ii) adding an activating agent dissolved in nitric acid to the precursor solution of step (i) to form a precursor solution; (iii) stirring the precursor solution of step (ii) and carrying out solvent evaporation to form a precursor; and (iv) heat treating the precursor of step (iii) to obtain a phosphor.

Description

The process of fluorescent substance based on YGd2O3: Eu using solvent evaporation method}

1a, 1b, 1c and 1d are scanning electron micrographs of the phosphor particles produced by the present invention,

Figure 2 is a graph of the results of X-ray diffraction analysis of the phosphor prepared by the present invention

Figure 3 is a graph of the luminescence properties of the phosphor prepared by the present invention.

The present invention relates to a method for producing an oxide-based phosphor by a solvent evaporation method, and more particularly to a method for producing a YGd ₂ O ₃ : Eu ³⁺ red color phosphor for PDP by a solvent evaporation method.

Currently, multicomponent oxide phosphors are mostly manufactured by a solid phase reaction method. In the solid phase reaction, the desired multicomponent oxide phosphors are finally obtained by mixing oxides of respective components and subjecting them to repeated heat treatment and grinding at high temperatures. . However, in order to obtain a pure composition in the solid phase reaction method, it has to go through a long time process at a high temperature and has to undergo a repeated heat treatment and pulverization process, so that impurities may be introduced into the phosphor particles, thereby degrading luminescence properties. In addition, the particles produced by the solid-phase reaction method has a disadvantage that the surface is rough and irregular in shape while having a size of several microns.

In order to solve the problems of the solid state reaction method as described above, the liquid phase reaction method and the gas phase reaction method have been studied a lot. Among them, the liquid phase reaction method such as sol-gel method or pechini method has the advantage of producing the desired multi-component phosphor at a very low temperature, unlike the solid phase reaction method, and the lower heat treatment temperature because the doping material can be mixed at the molecular level. It also has the advantage of expecting good fluorescence properties. However, the phosphor prepared by the conventional liquid phase reaction method has a disadvantage that it is difficult to use for displays requiring a uniform size and shape because the shape of the particles are non-uniform. In addition, the phosphor prepared by the gas phase method such as ultrasonic spray pyrolysis method has a problem of thermal stability due to the hollow form and high porosity.

Therefore, there is a need for a method of manufacturing an oxide phosphor having uniformly excellent luminescence properties that can be usefully used for a display in a simpler process.

The present invention is therefore to overcome the problems of the prior art as described above and to provide a method for producing an oxide phosphor having excellent light emission characteristics and can be usefully used for display in a simpler process, the object of the present invention is Small and spherical solvent evaporation method using chloride hydrate (YCl ₃ · 6H ₂ O), gadolinium chloride hydrate (GdCl ₃ · 6H ₂ O), and europium oxide (Eu ₂ O ₃ ) as a starting material The present invention provides a method for preparing an oxide-based phosphor, particularly a red phosphor, by the solvent evaporation method, which has a uniform form without aggregation, and can be manufactured more economically while improving luminescence properties, and a phosphor produced thereby.

In order to achieve the above object, the invention, by mixing the tree ium chloride hydrate _{(YCl 3 · 6H 2 O)} , gadolinium chloride hydrate (GdCl ₃ · 6H ₂ O) was dissolved in distilled water to precursor solution Preparing (S1);

Adding an active agent dissolved in nitric acid to the precursor solution in step S2 to form a precursor solution (S2);

Preparing a precursor by stirring the precursor solution in the step (S2) and evaporating the solvent (S3); And

It provides a method for producing a red light-emitting phosphor by the solvent evaporation method comprising the step (S4) of obtaining a phosphor by heat-treating the precursor in the step (S3).

In the above (S1), the mixing ratio of YCl ₃ .6H ₂ O and GdCl ₃ .6H ₂ O is preferably in a ratio of 2: 3. This is a ratio for showing the maximum light emission characteristics.

In addition, the active agent in the step (S2) is preferably using europium oxide (Eu ₂ O ₃ ) and the amount of the active agent is added to the base of the YCl ₃ · 6H ₂ O and GdCl ₃ · 6H ₂ O It is preferable to make it 1-7 wt% of the total weight.

In addition, the precursor preparation in step (S3) is preferably stirred for 2 hours at 60 ℃ precursor solution in step (S2) to evaporate the solvent and then calcined at 80 ℃ 24 hours. The reason for this is that solvent evaporation occurs rapidly above 60 ° C. and the reaction time becomes too long below, and drying conditions are general conditions.

In addition, the heat treatment in the step (S4) is preferably performed for 5 hours at 900 ~ 1100 ℃.

In the present invention, polyvinyl alcohol (PVA) may be used as a dispersant. The PVA may be added in step (S2) and may be added for controlling particle size and improving dispersibility made by solvent evaporation.

Hereinafter, the present invention will be described in more detail with reference to preferred embodiments.

For the practice of the present invention, YGd ₂ O ₃ : Eu ³⁺ red phosphor for PDP was prepared as follows.

First, the precursor solution was prepared by mixing YCl ₃ · 6H ₂ O and GdCl ₃ · 6H ₂ O in a ratio of 2: 3, dissolved in distilled water, and then adding Eu ₂ O ₃ dissolved in nitric acid. Vinyl alcohol (PVA) was used. Then, the mixed precursor solution was stirred at 60 ° C., and the precursor obtained by evaporating the solvent was dried at 80 ° C. for 24 hours and calcined to prepare a phosphor.

In order to examine the luminescence properties of the phosphor according to the doping concentration of the active agent, the amount of Eu ₂ O ₃ was changed from 1wt% to 7wt%. In addition, in order to examine the change according to the heat treatment temperature was carried out by increasing the temperature from 900 ℃ to 1300 ℃ by 100 ℃ it was confirmed that the optimum heat treatment conditions of the excellent crystallinity and luminescence properties of the particles at 1100 ℃.

Crystallinity and crystal structure of the prepared YGd ₂ O ₃ : Eu ³⁺ red luminescent phosphor for PDP were confirmed by X-ray diffractometer (XPD; X-ray diffractometer), and scanning electron microscope (FE-SEM; field emission) Particle size, shape, and size distribution were determined by scanning electron microscope (PSA) and particle size analyzer (PSA). The optical properties of the phosphor particles were confirmed by using a spectrophotometer (PL) to confirm the light emission characteristics (PL), and to excite the particles using a xenon lamp (xenon lamp) to generate a VUV.

Example 1

As described above, YCl ₃ · 6H ₂ O and GdCl ₃ · 6H ₂ O are mixed in a ratio of 2: 3 in a stoichiometric ratio, and dissolved in distilled water. Then, ₃ wt% of the active agent Eu ₂ O ₃ is added to the parent content. The solution was completely dissolved in nitric acid solution. The prepared precursor solution was stirred at 80 ° C. for 24 hours to evaporate the solvent. The obtained precursor was heat-treated at 900 ° C. for 5 hours to prepare a phosphor, and the SEM, XRD, and PL analyzes were performed. The results are shown in FIGS. 1A, 1B, 1C, 1D, 2, and 3, respectively.

Example 2

Precursor solution preparation and solvent evaporation were carried out as in Example 1, and the resulting precursor was heat-treated at 1000 ° C. for 5 hours to prepare a phosphor, followed by SEM, XRD, and PL analysis. 1b, 1c, 1d, FIG. 2 and FIG. 3, respectively.

Example 3

The precursor obtained as in Example 1 was heat-treated at 1100 ° C. for 5 hours to prepare a phosphor, and then SEM, XRD, and PL analysis was performed, and the results are shown in FIGS. 1A, 1B, 1C, 1D, and FIG. 2 and 3, respectively.

Example 4

The precursor obtained as in Example 1 was heat-treated at 1200 ° C. for 5 hours to prepare a phosphor, followed by SEM, XRD, and PL analysis, and the results are obtained as shown in FIGS. 1A, 1B, 1C, 1D, and FIG. 2 and 3, respectively.

As a result of analyzing the results according to the above embodiment, as shown in SEM pictures of YGd ₂ O ₃ : Eu ³⁺ phosphor particles prepared by changing the heat treatment temperature as shown in FIGS. 1A, 1B, 1C, and 1D, the heat treatment temperature was At 900 ° C, the particle size was formed with particles below 100 nm (see Figure 1a), and when the heat treatment temperature was increased to 1000 ° C, the particle size increased and the particles became relatively uniform (see Figure 1b), Figure 1c. As shown in FIG. 1D, the phosphor fired at 1100 ° C. exhibited a particle size of about 150 nm. However, when heat-treated at 1200 ° C. or more, as shown in FIG.

In addition, as can be seen in the X-ray diffraction analysis results of FIG. 2, the YGd ₂ O ₃ : Eu ³⁺ phosphor prepared according to the above embodiment was found to exhibit crystallinity at 900 ° C., and the heat treatment temperature increased to 1100 ° C. As a result, it was confirmed that the crystallinity also increased. Therefore, it can be seen that the phosphor prepared by the solvent evaporation method of the present invention has excellent crystallinity and a single phase even at a relatively low temperature compared to the solid phase reaction method of heat treatment at a high temperature of 1500 ° C. or higher.

Figure 3 is a graph showing the emission characteristics of the YGd ₂ O ₃ : Eu ³⁺ phosphor particles produced by the present invention. As can be seen from FIG. 3, the luminescence spectrum of the phosphor according to the present invention was observed at 612 nm due to the ⁵ DO → ⁷ F ₂ transition of Eu ³⁺ regardless of the heat treatment temperature. In addition, as the heat treatment temperature increases from 900 ° C to 1100 ° C, the luminescence intensity also increases, which is believed to be due to the decrease in scattering on the surface as well as the increase in crystallinity which increases the optical transition probability as the heat treatment temperature increases. In general, important factors for determining luminous efficiency include chemical composition, particle size and arrangement, and optimization of particle shape. Therefore, as the heat treatment temperature increases, the particles become larger and have a uniform structure. The branched particles act as an important factor for the scattering is reduced in addition to the higher particle packing density, but heat treatment at too high a temperature of more than 1200 ℃ as shown in Figure 1 may cause the particles to entangle with each other due to agglomeration at the surface of the desirable heat treatment As for temperature, 1200 degrees C or less is preferable.

As described above, according to the present invention, it is possible to provide a multi-component complex phosphor having a small and uniform shape and excellent in luminescence properties, and is manufactured at a lower heat treatment temperature than in the solid phase reaction method, thereby economically advantageously producing the phosphor. You can expect the effect.

Claims (5)

A method for producing a red light-emitting phosphor by a solvent evaporation method, comprising: dissolving YCl ₃ · 6H ₂ O and GdCl ₃ · 6H ₂ O in distilled water to prepare a precursor solution (S1); Adding an active agent dissolved in nitric acid to the precursor solution in step S1 to form a precursor solution (S2); Stirring the precursor solution in step S2 to evaporate the solvent to prepare a precursor (S3); And Comprising a step (S4) of obtaining a phosphor by heat-treating the precursor in the step (S3), the manufacturing method of the red light-emitting phosphor. According to claim 1, YCl ₃ · 6H ₂ O with GdCl ₃ · 6H ₂ O 2 ratio of mixing of stoichiometric in the above step (S1): 3 to hereinafter, the method for producing a red light-emitting phosphor comprising a. According to claim 1, wherein the active agent in the step (S2) is Eu ₂ O ₃ , the addition amount is 3 ~ 7wt% of the total weight of the YCl ₃ · 6H ₂ O and GdCl ₃ · 6H ₂ O as the parent contained in the precursor solution Method of producing a red light-emitting phosphor comprising a. The method according to claim 1, wherein the precursor preparation in step (S3) comprises the precursor solution in step (S2) is stirred for 2 hours at 60 ℃ to evaporate the solvent and then dried for 24 hours at 80 ℃ Method for producing a phosphor for luminescence. The method of claim 1, wherein the heat treatment in step S4 is performed at 900 to 1100 ° C. for 5 hours.

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