KR100992949B1 - Synthesizing process of phosphor - Google Patents

Abstract

In the present invention, in the production of green nano-phosphor used for PDP and inkjet, by adding silica-sol, the sol-gel process can replace the phosphor manufacturing process, thus eliminating harmful substances and washing process. Even if the gel process is replaced, the particle shape, crystallinity, light emission intensity of the green phosphor can be maintained, and to provide a method for producing a phosphor that can produce a phosphor at a lower temperature than the conventional solid-state method.

The technical configuration of the method of manufacturing a phosphor for use in a plasma display panel (PDP) or an ink jet, to dissolve the starting material, Zn (NO3) 2 · 6H2O, and _{Mn (NO 3) 2 · X} H 2 O in deionized water First step; A second step of adding and dissolving the citric acid so that a molar ratio of the solution of the first step and the citric acid is 3: 1; A third step of mixing nitric acid (HNO ₃ ) such that the pH of the second step solution is 1 to 2; A fourth step of dropping the silica-sol while stirring the solution of the third step to obtain a uniform precursor; A fifth step of synthesizing the green phosphor by stirring the solution of the fourth step for a predetermined time, burning the burned powder in a heater, and calcining and cooling the powder in an alumina crucible in an air or oxygen atmosphere; And a sixth step of reacting the green phosphor in a reducing atmosphere of nitrogen and hydrogen.

sol-gel, PDP, inkjet, green, nanophosphor, Zn2SiO4: Mn, silica-sol

Description

Phosphor Production Method {SYNTHESIZING PROCESS OF PHOSPHOR}

The present invention relates to a method for producing a phosphor, and to a method for producing a nano-phosphor that can eliminate the harmful substances and water washing process using a sol-gel process, and obtain uniform particle characteristics at a lower temperature.

In general, a fluorescent material (fluorescent material) is a material that emits fluorescence, petroleum, lead glass, platinum cyanide, and the like, the practical one is described as ZnS: Cu, mainly used for CRT and electron microscope. Depending on the combination of the raw material and the activator to be added, it can be manufactured according to the purpose to give a color.

 The fluorescent material is also called a phosphor, and is produced by adding a small amount of an activator (silver, copper, manganese, lead, etc.) to zinc sulfide ZnS or a mixture of zinc sulfide and cadmium sulfide, and then calcining it to about 1,000 ° C. It describes as Cu. These zinc sulfides are mainly used for CRTs, X-rays and electron microscopes.

Sulfide or silicate is usually used as the fluorescent material, and the mixing ratio of zinc sulfide and cadmium sulfide and the selection of an activator are important. In luminous paints, long-lived radioactive materials such as radium salts are mixed and always emit light by stimulation of α-rays emitted from them.

In addition, a light-emitting agent is a substance that emits light by transferring an energy-absorbed electromagnetic field from an excited state (excited state) to a low energy state through an intermediate stage sometimes.

In addition, definition is often made according to a light emitting mechanism, and the definition is slightly different depending on whether the light emitting agent is an inorganic crystal or an organic material. Applications include fluorescent lamps, anode wires, television screens, display devices, X-ray reinforcement screens, stamp marks, fiber whitening, and the like. Examples of light emitting materials used in lighting include calcium halophosphate [Ca ₅ (PO4) ₃ (F · Cl ): Sb, Mn] and zinc silicate [Zn ₂ SiO ₄ : Mn (II)].

Such display devices are classified into a self-luminous display that emits light by itself and a non-luminous display that uses a separate lamp instead of emitting light by itself.

Representative examples of the non-luminous display are LCD (Liquid Crystal Display), and representative examples of the self-luminous display are CRT, PDP, OLED, and the like.

Phosphor is essentially used for the self-luminous display apparatus among such display apparatuses, and the types of such phosphors are as follows.

First of all, PL (Photo Luminescence) refers to a phenomenon in which a material is stimulated by light to emit light by itself, and a typical example is fluorescence or phosphorescence, and is a phenomenon generated by reproducing light absorbed from the surroundings. The wavelength of is equal to or longer than the wavelength of the absorbed light.

In addition, a phosphor that is excited by ultraviolet rays to generate visible light is typically a phosphor used in a PDP, and an example used in the PDP is a red light such as Y (V, P) O ₄ : Eu ⁺³ . Phosphor for green light, phosphor for green light such as ZnSiO ₄ : Mn, YBO ₃ : Tb, and blue light phosphor such as BaMgAl ₁₀ O ₁₇ : Eu.

The luminescence properties of such phosphors depend on the particle shape and crystallinity, and the phosphors are prepared by solid phase reactions requiring long-term heat treatment at high temperatures, and oxidized with acid white room in Patent Publication No. 2008-0000731 using such solid phase reactions. Disclosed is a method for producing a nano-sized red phosphor by pulverization and firing from a gel powder by a sol-gel process and heat treatment using europium as a starting material.

The above patent discloses dissolving yttrium oxide and europium in an aqueous solution of nitric acid at an appropriate concentration, so that an aqueous solution containing yttrium and europium is dissolved in citric acid, citric acid, citric acid and ester reaction, and the starting solution is maintained in an emulsion state. After the sol-gel reaction is performed by adding an appropriate amount of a nonionic surfactant, a gel powder is prepared by heating and heating the unevaporated solution present in the gel through heat treatment of the obtained gel, and then pulverized and then calcined at an appropriate temperature to obtain a uniform solution. It provides a method for producing a red phosphor having a nano-size, the detailed description thereof will be omitted.

These methods use organic solvents called Tetra Ethyl Ortho Silicate (TEOS) when synthesizing silicate phosphors by wet methods, in which case harmful organic substances are generated during the synthesis process and must be washed with water. do.

In addition, the manufacturing method by the solid-phase reaction as described above has the disadvantage that the composition of the material is irregular, the structural uniformity is low, and the size of the crystal irregularly large, these characteristics are difficult to be applied to high performance display devices and inkjet have.

The present invention has been made in order to solve the above problems, by synthesizing the phosphor by a sol-gel process using a silica-sol instead of the conventional TEOS organic solvent, no harmful organic substances are generated, it is possible to eliminate the washing process It is an object to provide a method for producing a phosphor.

Another object of the present invention is that the synthesized phosphor is a single phase even when using a silica-sol, the luminescence intensity can be maintained, the crystallinity is excellent even if produced at a lower temperature than the solid phase method, and the willemite lattice is maintained. It is to provide a method for producing a phosphor that can be.

In order to achieve the above object, the present invention provides a method for producing a phosphor used for a plasma display panel (PDP) or inkjet, Zn (NO ₃ ) ₂ · 6H ₂ O and Mn (NO ₃ ) as starting materials _2, a first step for dissolving the _X H ₂ O in deionized water; A second step of adding and dissolving the citric acid so that a molar ratio of the solution of the first step and the citric acid is 3: 1; A third step of mixing nitric acid (HNO ₃ ) such that the pH of the second step solution is 1 to 2; A fourth step of dropping the silica-sol while stirring the solution of the third step to obtain a uniform precursor; A fifth step of synthesizing the green phosphor by stirring the solution of the fourth step for a predetermined time, burning the burned powder in a heater, and calcining and cooling the powder in an alumina crucible in an air or oxygen atmosphere; And a sixth step of reacting the green phosphor in a reducing atmosphere of nitrogen and hydrogen.

And, in the fifth and sixth step, the temperature of the air atmosphere and the reducing atmosphere is 800 to 1000 ℃, the temperature of the oxygen atmosphere and the reducing atmosphere is characterized in that 300 to 900 ℃.

In addition, the light emission intensity of the green phosphor increases as the amount of manganese or the heat treatment temperature or the amount of silica-sol added increases.

In addition, the amount of manganese is characterized in that x is 0.02 to 0.08 based on the green phosphor (Zn ₂ - _X Mn _X SiO ₄ ).

In addition, the green phosphor is characterized in that the single phase and / or single crystal compound.

The green phosphor is characterized in that the single-phase compound.

Here, the particle size of the green phosphor formed after the heat treatment is characterized in that 200 to 600 nm.

And, the deionized water of the first step is characterized in that the tertiary distilled water.

In addition, the reducing atmosphere of the six steps is characterized in that consisting of 96% nitrogen, 4% hydrogen.

As described above, according to the present invention having the above-described configuration, the nano-phosphor is synthesized by a sol-gel process using a silica-sol, and thus, since no harmful organic substance is generated, the washing process can be eliminated, thereby simplifying the process, and the harmful substance. This does not occur, the toxicity of the finished product can be eliminated, it is possible to maintain a constant luminescence intensity and shape, even if produced at a lower temperature than the solid state method, the crystallinity is excellent, the willemite lattice can be maintained Can be harvested.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

First, the concept of the present invention will be described.

The use of the Pechini process in the sol-gel process can provide stoichiometric fine and uniform powders (MP Pechini, US Patent No. 3,330,697 (1967)). , JH Choy, YS Han, SH Hwang, SH Byeon, and G. Demazeau, J. Am. Ceram.Soc, 81, 3197 (1998), JH Choy and YS Han, J. Mater. Chem, 7, 1815 (1997 ), JH Choy and YS Han, Mater. Lett, 32, 209 (1997), JH Choy and YS Han SW Song, and SH Chang, J. Mater.chem, 4, 1271 (1994), JH Choy and YS Han, JT Kim, and YH Kim, J. Am. Ceram. Soc, 78, 1169 (1995), JH Choy and YS Han, JH Sohn, and M. Itoh, J. Am. Ceram. Soc, 78, 1169 (1995) , YC Kang, SB Park, IW Lenggoro and K. Okuyama, J. Phys Chem.Solids. 60, 379 (1999)).

In addition, because the materials are mixed atomically in the precursor solution, which is the material that precedes the material, the intermediate material obtained through the sol-gel process has a high porosity because the high temperature is not required to disperse the metal ions. It is soft and is suitable for obtaining finely dispersed oxide particles.

In the pechini process, a process using a polyalcohol such as ethylene glycol (ethylene glycolohol) is used to increase the solubility and aid in esterification of citric acid, which is organic during heat treatment of the precursor in the gel state. The burning heat of the material can inhibit the aggregation of the particles.

Therefore, the present invention solves the problem of agglomeration of particles by introducing a sol-gel process using only the chelating ability of carboxyl groups present in hydrochloric acid without using an esterification catalyst, and mainly used in PDP and inkjet. When synthesizing Zn ₂ SiO ₄ : Mn, which is a green phosphor, the crystal structure, crystallinity, and fluorescence characteristics of particles are not changed by using silica-sol without using a conventional tetraethyl orthosilicate (TEOS) reagent. To help.

First, the sol-gel process refers to a series of processes involving the transition from a fluidized sol (Sol) to a gel that exhibits semi-solid viscoelastic properties, and the reactants used in the sol-gel process are dissolved in a solvent. Molecular units having a size of 1 nm or less are used.

Here, sol (Sol) is composed of particles of about 1 ~ 1000nm generally refers to colloidal particles dispersed uniformly without precipitation due to the action of van der Waals attraction or surface charge, the gel (Gel) is one It refers to macromolecules that are dispersed throughout the liquid phase in which molecules are dispersed by polymerization or aggregation of particle sols.

The sol-gel process is a hydration reaction in which a reactant (molecular compound, etc.) reacts with water to form a hydroxy (-OH) functional group around a metal, and one water molecule is formed from two hydroxy functional groups. It is a process in which reactants and reactants are connected to each other and grow through condensation, which is simultaneously released and forms a metal-oxygen bond.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a diagram illustrating a process of synthesizing a Zn ₂ SiO ₄ : Mn phosphor according to the present invention by a sol-gel process.

The present invention contains Zn ₂ SiO ₄ : Mn by a Sol-Gel method using a metal-citrate complex among various chemical synthesis methods, and particularly for metals having high fire resistance. Take advantage of strong chemical bonding of citrate.

First, Zn (NO ₃ ) _{2 ·} 6H ₂ O (aldrich, 97%) and Mn (NO ₃ ) _{2 ·} xH ₂ O (Junsei, 67%) are used as starting materials of the phosphors. Calculate theoretically and weigh precisely.

Then, starting materials Zn (NO ₃ ) _{2 ·} 6H ₂ O (aldrich, 97%) and Mn (NO ₃ ) _{2 ·} xH ₂ O (Junsei, 67%) were dissolved in deionized water (S10), Deionize water used in the present invention uses tertiary distilled water (250 ml).

In addition, citric acid is added to the transparent solution dissolved in the step (S10), but the mixture is mixed so that the molar ratio (Molar Rate) of the metal ions of the citric acid and the transparent solution is 3: 1 (S20).

Here, the tertiary distilled water dissolves Zn (NO ₃ ) _{2 ·} 6H ₂ O, Mn (NO ₃ ) _{2 ·} xH ₂ O, and hydrochloric acid.

Thus, the pH is adjusted to 1 to 2 using silver nitrate with respect to the transparent solution dissolved in the step (S20) (S30), and stir strongly to obtain a homogeneous precursor (Stirring).

While stirring, a drop of silica-sol was added dropwise (S40) and stirred vigorously for about 24 hours, and then burned at 300 to 400 ° C. heater for about 24 hours, and the burned powder was ground (S50).

Thereafter, a certain amount is placed in an alumina crucible (Alumina Boat), and the temperature is changed to 800 to 1000 ° C. in an air atmosphere, followed by sintering and furnace cooling in an electric furnace to room temperature (S60).

The synthesized silicate (Zn ₂ SiO ₄ ) green phosphor is reacted for 4 hours in N ₂ 96%, H ₂ 4% reducing atmosphere at 800 ° C. (S70).

In order to analyze the characteristics of the Zn ₂ SiO ₄ : Mn phosphor powder synthesized by the sol-gel process according to the present invention, X-ray diffraction analysis, scanning electron microscope (SEM) analysis, and emission intensity analysis are performed.

The X-ray diffraction (XRD) analysis was performed using an X-ray diffraction tester (Shimazu, XRD-6000 model) using Cu-Kα radiation (λ = 1.5418 kV), an acceleration voltage of 30 kV, and a current of 30 mA. , In a diffraction angle (2θ) of 10 to 70 °.

Here, the scanning speed of the X-ray diffraction tester was obtained at a diffraction spectrum of 2 ° per minute, and the crystallinity of the powder according to the change of Mn concentration, heat treatment temperature, and silica-sol of the phosphor synthesized by the sol-gel process was measured. Reference was made to powder diffraction files of Joint Committee on Powder Diffraction Standards (JCPDS).

In addition, Scanning Electron Microscopy (SEM) analysis was performed at 15kV to measure the change of surface shape and particle size of the powder according to the heat treatment temperature and silica-sol variation of the phosphor synthesized by the sol-gel process. It observed using (Hitachi, S-4200 model).

In addition, in order to obtain a photoluminescence (PL) spectrum of the phosphor according to the present invention, a spectrophotometer (Shimazu, RF-5301PC model) was measured at room temperature.

The synthesized phosphor according to the present invention was ground in a mortar and mounted on a holder for measuring luminescence. The luminescence spectrum was excited by a sample with a wavelength of 254 nm to obtain a spectrum in the range of 450 to 600 nm.

Here, the filter (UV-39) was used to remove the second order Rayleigh scattering of the excitation wave in the emission measurement.

2 is an X-ray diffraction graph according to manganese concentration of Zn ₂ SiO ₄ : Mn phosphor powder synthesized by a sol-gel process according to the present invention.

In FIG. 2, the sol-gel process of FIG. 1 is performed by varying the concentration of manganese in the starting material.

In this case, the graph described as commerical is a sample to which commercial manganese concentration is applied, (a) is a sample having an x value of 0.02 based on the green phosphor (Zn ₂ - _X Mn _X SiO ₄ ), and (b) is a x value of 0.05 (c) has an x value of 0.08 and (d) has an x value of 0.12.

Here, X-ray diffraction patterns are measured after each sample is heat-treated at 1000 ° C. for 6 hours and reacted at 800 ° C. for 4 hours.

The X-ray diffraction pattern of the synthesized Zn ₂ SiO ₄ : Mn sample was compared with the JCPDS card, and the synthesized samples were all synthesized as a single phase compound of Willemite. have.

3 is an electron micrograph showing the manganese concentration of Zn ₂ SiO ₄ : Mn phosphor powder synthesized by the sol-gel process according to the present invention, and Zn _2-x Mn _x SiO ₄ green phosphor was synthesized at 900 ° C. FIG. SEM image of morphology change by increasing the amount of manganese in a sample

First, (a), (b), (c), and (d) have the manganese concentrations of x = 0.02, 0.05, 0.08, and 0.12 based on the green phosphor (Zn ₂ - _X Mn _X SiO ₄ ) as described above. It is the SEM photograph at the time of setting respectively.

It can be seen that as the amount of manganese increases, the particle size grows little by little.However, increasing the amount of manganese to x = 0.12 shows that the particles do not form a spherical shape with each other. It is preferable not to increase = 8, ie 8 mol% or more.

4 is a graph showing light emission intensity according to manganese concentration of Zn ₂ SiO ₄ : Mn phosphor powder synthesized by a sol-gel process according to the present invention. As shown in FIG. 4, optimum chemical composition, distribution of particle size, particle shape, and the like are required as conditions for increasing the luminous efficiency of the phosphor.

However, when the shape of the powder particles is spherical, light scattering is small on the surface and has a high layer density, so that the luminous efficiency may be increased.

First, FIG. 4 shows Zn _2-x Mn _x SiO ₄ ((a) to (d) are samples in which the amount (x) of manganese is treated as x = 0.02, 0.05, 0.08, and 0.12, respectively). Comparing the light emission (PL) spectra of the samples, the commerical shows the spectra for samples treated with commercial amounts of manganese.

Here, although the emission intensity increased as the amount of manganese increased, it was found that the emission intensity decreased when the amount of substituted manganese was 12 mol%, so the concentration of manganese was most preferably 8 mol%. .

5 is an X-ray diffraction analysis graph according to the heat treatment temperature of Zn ₂ SiO ₄ : Mn phosphor powder synthesized by the sol-gel process according to the present invention, which is an X-ray diffraction pattern measured after heat treatment at each temperature. .

Here, X-ray diffraction patterns of the synthesized Zn _{2 - x} Mn _x SiO ₄ samples were compared with the JCPDS card, and as a result, all synthesized samples were synthesized as a single phase compound of Willemite. Able to know.

In general, in the solid phase reaction, the smaller the particle size and the closer to the spherical shape, the easier the surface diffusion is because the specific surface area (Skyhalo) representing the surface area of the particles per unit mass or volume of the material increases.

However, there are limitations to reducing the size of the particles, and it is not easy to control the shape of the particles, and high temperature heat treatment is required to form a single phase, whereas in the sol-gel process, each component is uniformly mixed in atomic units. Since the materials are likely to diffuse together, single phase formation is possible at low temperatures.

In addition, because the particles have a high specific surface area, they can easily participate in the reaction.

6 is a view showing an electron micrograph according to the heat treatment temperature of the Zn ₂ SiO ₄ : Mn phosphor powder synthesized by the sol-gel process according to the present invention, as the temperature of Zn _1.92 Mn _0.08 SiO ₄ green phosphor is increased SEM image of morphology change.

Here, as the heat treatment temperature rises, the fine particles aggregate to form one particle and the size of the particles increases (a: 50,000 times), and at 800 ° C., the size of one particle is 200-300 nm spherical, and (b: 50,000 times ) At 900 ℃, the particle size was about 600 nm at 300 ~ 400 nm and (c: 50,000 times), but at 1000 ℃ (d: 5000 times), the particle distribution was uneven at 1200 ℃.

FIG. 7 is a graph showing luminescence intensity according to the heat treatment temperature of Zn ₂ SiO ₄ : Mn phosphor powder synthesized by the sol-gel process according to the present invention, excited at 254 nm, and measured by luminescence spectra.

As the heat-treated temperature increased (a: 800 ° C., b: 900 ° C., c: 1000 ° C., d: 1200 ° C.), the light emission intensity increased, but the difference between the light emission intensity between 1000 ° C. and 1200 ° C. was not so large.

This is thought to be due to the deterioration of the shape at 1200 ° C as compared to 1000 ° C as shown in the SEM photograph. From these results, it can be seen that the heat treatment (firing) temperature is most suitable for 1000 ℃.

8 is an X-ray diffraction analysis graph of silica-sol content of Zn ₂ SiO ₄ : Mn phosphor powder synthesized by a sol-gel process according to the present invention. In order to confirm the crystallinity according to the silica-sol variation, the amount of silica-sol in Zn _1.92 Mn _0.08 SiO ₄ was (a) no excess, (b) 10% excess, (c) X-ray diffraction patterns of samples synthesized at 1000 ° C. varying differently by more than 20%.

The X-ray diffraction pattern of the synthesized Zn ₂ SiO ₄ : Mn sample was compared with the JCPDS card, and it can be seen that the synthesized samples were all synthesized as a single crystal compound of Willemite.

Here, it can be seen that the excess silica-sol does not affect the structure of Zn ₂ SiO ₄ or form a secondary phase.

9 is a view showing an electron micrograph according to the silica-sol content of the Zn ₂ SiO ₄ : Mn phosphor powder synthesized by the sol-gel process according to the present invention. As shown in FIG. 9, when the Zn _1.92 Mn _0.08 SiO ₄ green phosphor is synthesized at 1000 ° C., the morphological change can be confirmed as the amount of silica-sol increases.

First, when the amount of silica-sol is (a) no excess and (b) more than 10%, the particle shape is almost similar, but if (c) is more than 20%, particles are aggregated. Able to know.

Therefore, when the silica-sol is added above a certain level it can be seen that not only the light intensity of the Zn _1.92 Mn _0.08 SiO ₄ green phosphor but also a bad result in the form.

10 is a graph showing luminescence intensity according to silica-sol content of Zn ₂ SiO ₄ : Mn phosphor powder synthesized by a sol-gel process according to the present invention. A, _0.08 a Zn _{1 .92} Mn ₀ heat treatment at 1000 ℃ as shown in Figure 10 SiO ₄ The emission spectra according to the amount of change in the silica-sol of the phosphor are compared.

Here, it can be seen that the luminescence intensity is higher when (b) more than 10% of (b) no excess of silica-sol, which means that (b) more than 10% of the sample is ideal for manganese and O by the meet four coordination in the crystal system is caused because the transformation of the ⁴ → ⁶ a T _{1g 1g} of Mn efficiently.

In the method of manufacturing the phosphor according to the present invention, all samples synthesized at 800 ° C. or higher obtained a single phase, and it was confirmed through XRD that the Willemite lattice was maintained even when using other silica-sol instead of TEOS.

In addition, in the emission intensity measurement, it was observed that the emission intensity was almost the same as that of the green phosphor for the PDP of the commercial product, and the SEM size also showed that the particle size was the level of the green phosphor of the commercial product.

In addition, the phosphor synthesized by the sol-gel process according to the present invention can synthesize a phosphor excellent in crystallinity at a low temperature of 800 ℃ compared to the conventional solid-state method.

FIG. 11 is a diagram illustrating a process of synthesizing a Zn 2 SiO 4: Mn nanophosphor according to the present invention using a sol-gel process, and the reagents and molecular weights shown in Table 1 below are shown.

The present invention contains a silicate (Zn ₂ SiO ₄ ) by the Sol-Gel method using a metal-citrate complex among various chemical synthesis methods, in particular for metals with high fire resistance Take advantage of the strong chemical bonding of and citrate.

First, Zn (NO3) 2.6H2O (aldrich, 97%) and Mn (NO3) 2xH2O (Junsei, 67%) are used as starting materials of the phosphor. Weigh.

Then, the starting material Zn (NO 3) 2 .6H 2 O (aldrich, 97%) and Mn (NO 3) 2 .xH 2 O (Junsei, 67%) were dissolved in deionized water (S100). Deionize Water) uses tertiary distilled water (1000 ml).

In addition, citric acid is added to the transparent solution dissolved in the step (S100), but the mixture is mixed so that the molar ratio (Molar Rate) of the metal ions of the citric acid and the transparent solution is 3: 1 (S200).

Here, the tertiary distilled water may include dissolving all of Zn (NO 3) 2 · 6H 2 O, Mn (NO 3) 2 xH 2 O, and hydrochloric acid, and stirring until completely dissolved.

Thus, the pH is adjusted to 1 to 2 using nitric acid for the transparent solution dissolved in the step (S200) (S300), and stir strongly to obtain a homogeneous precursor (Stirring).

While stirring the silica-sol drop by drop (S400) vigorously stirred for about 24 hours, and then burned for about 24 hours in a 300 to 400 ℃ heater, the burned powder is ground (S500)

Thereafter, a predetermined amount is put in an alumina crucible (Alumina Boat) and calcined at 500 ° C. in an oxygen atmosphere, and then the oven is cooled to room temperature in an electric furnace and changed (S600).

The thus synthesized silicate (Zn 2 SiO 4: Mn) green phosphor precursor is reacted for 4 hours in 900% N 2 96%, H 2 4% reducing atmosphere (S700).

In order to analyze the characteristics of the Zn ₂ SiO ₄ : Mn nano phosphor powder synthesized by the sol-gel process according to the present invention, X-ray diffraction analysis, scanning electron microscopy (SEM) analysis, and emission intensity analysis are performed.

The X-ray diffraction (XRD) analysis was performed using an X-ray diffraction tester (Shimazu, XRD-6000 model) using Cu-Kα radiation (λ = 1.5418 kV), an acceleration voltage of 30 kV, and a current of 30 mA. , In a diffraction angle (2θ) of 10 to 70 °.

Here, the scanning speed of the X-ray diffraction tester was obtained at a diffraction spectrum of 2 ° per minute, and the crystallinity of the powder according to the change of Mn concentration, heat treatment temperature, and silica-sol of the phosphor synthesized by the sol-gel process was measured. Reference was made to powder diffraction files of Joint Committee on Powder Diffraction Standards (JCPDS).

In addition, Scanning Electron Microscopy (SEM) analysis was performed at 15kV to measure the change of surface shape and particle size of the powder according to the heat treatment temperature and silica-sol variation of the phosphor synthesized by the sol-gel process. It observed using (Hitachi, S-4200 model).

In addition, in order to obtain a photoluminescence (PL) spectrum of the nanophosphor according to the present invention, it was measured at room temperature using a spectrophotometer (Shimazu, RF-5301PC model).

The synthesized nano-phosphor according to the present invention was ground in a mortar and mounted on a holder for measurement of luminescence, and the emission spectrum was excited by a sample at a wavelength of 254 nm to obtain a spectrum in the range of 450 to 600 nm.

Here, the filter (UV-39) was used to remove the second order Rayleigh scattering of the excitation wave in the emission measurement.

12 is an X-ray diffraction analysis graph of Zn ₂ SiO ₄ : Mn nano phosphor powder synthesized by the sol-gel process according to the present invention, and analyzes the structure of the nano phosphor according to the present invention.

Here, it can be seen that the nano-phosphor according to the present invention exhibits the same pattern as that of the commercial phosphor shown on the top, and is synthesized as a compound having a single phase? Willemite structure.

In addition, the characteristics of the inkjet phosphor should generally be nano-sized spherical particles having excellent luminescence properties. In the nano-ization process, particles generally exhibit weak sintering on the particle surface, and this aggregation is a ball mill process in which a dispersant is added. Separate into individual particles.

In addition, the phosphor obtained by the phosphor synthesis process in which the particles are agglomerated severely in the heat treatment process of the phosphor particles is not a preferable nanonization process because the luminescent properties are inhibited in a substantial proportion in a strong ball mill process.

Therefore, the nano phosphor according to the present invention synthesized an optimal green nano phosphor through various heat treatment processes, which are shown in FIGS. 13 to 17.

FIG. 13 is a phosphor reduced at 900 ° C. after treatment with air at 900 ° C., FIG. 14 is a phosphor reduced at 800 ° C. after 900 ° C. thermal shock, and FIG. 15 is a 900 ° C. thermal shock. After the shock), it is a phosphor reduced at 900 ℃, Figure 16 is a phosphor reduced in 800 ℃ after treatment with oxygen, Figure 17 is a phosphor synthesized by the sol-gel process according to the present invention, oxygen at 500 ℃ The nanophosphor was reduced at 900 ° C. after treatment with.

As can be seen from the particle shape of the phosphor shown in Figures 13 to 16, the aggregation between particles is getting worse, the nano-phosphor according to the present invention shown in Figure 17 can be easily separated particles in the ball mill conditions used in the present invention It can be seen that.

FIG. 18 is a graph showing luminescence intensity according to the synthesis conditions of XnSiSiO4: Mn nano-phosphor powder synthesized by the sol-gel process according to the present invention, and shows the spectrum obtained by changing the Xenon Lamp at 254 nm to 450-600 nm. Relative emission intensity (%) according to the synthesis conditions is shown in Table 2 below.

As shown in FIG. 18, it can be seen that completely removing the organic matter in the oxygen atmosphere, which is a step before the final reduction treatment, can minimize the aggregation of the nano phosphors. Referring to Table 3 below, the reduction treatment is the final step. It can be seen that 900 ℃ is the optimum temperature.

Therefore, the nano-phosphor synthesized by the sol-gel process according to the present invention can be easily separated from the particles to be used for the inkjet, the aggregation between the particles can be removed to increase the luminescence properties.

In the above described exemplary embodiments of the present invention by way of example, the scope of the present invention is not limited only to this specific embodiment, and those skilled in the art within the scope of the claims of the present invention Changes may be made as appropriate.

1 is a diagram illustrating a process of synthesizing a Zn ₂ SiO ₄ : Mn phosphor according to the present invention using a sol-gel process.

2 is an X-ray diffraction analysis graph according to manganese concentration of Zn ₂ SiO ₄ : Mn phosphor powder synthesized by a sol-gel process according to the present invention.

3 is an electron micrograph of manganese concentration of Zn ₂ SiO ₄ : Mn phosphor powder synthesized by a sol-gel process according to the present invention.

Figure 4 is a graph of the emission intensity according to the manganese concentration of the xnSiSiO4: Mn phosphor powder synthesized by the sol-gel process according to the present invention.

5 is an X-ray diffraction graph according to the heat treatment temperature of Zn ₂ SiO ₄ : Mn phosphor powder synthesized by the sol-gel process according to the present invention.

6 is an electron micrograph showing the heat treatment temperature of Zn ₂ SiO ₄ : Mn phosphor powder synthesized by a sol-gel process according to the present invention.

7 is a graph showing light emission intensity according to heat treatment temperature of Zn ₂ SiO ₄ : Mn phosphor powder synthesized by a sol-gel process according to the present invention.

8 is an X-ray diffraction graph according to silica-sol content of Zn ₂ SiO ₄ : Mn phosphor powder synthesized by a sol-gel process according to the present invention.

9 is a view showing an electron micrograph according to the silica-sol content of Zn ₂ SiO ₄ : Mn phosphor powder synthesized by the sol-gel process according to the present invention.

10 is a graph showing light emission intensity according to silica-sol content of Zn ₂ SiO ₄ : Mn phosphor powder synthesized by a sol-gel process according to the present invention.

FIG. 11 is a diagram illustrating a process of synthesizing a Zn 2 SiO 4: Mn nanophosphor according to the present invention using a sol-gel process. FIG.

12 is an X-ray diffraction graph of a Zn 2 SiO 4: Mn nano phosphor powder synthesized by a sol-gel process according to the present invention.

13 to 17 are electron micrographs according to the synthesis conditions of the Zn 2 SiO 4: Mn nano phosphor powder synthesized by the sol-gel process according to the present invention.

18 is a graph showing light emission intensity according to synthesis conditions of Zn 2 SiO 4: Mn nano phosphor powder synthesized by a sol-gel process according to the present invention.

Claims (9)

In the manufacturing method of the fluorescent substance used for a plasma display panel (PDP) or an inkjet, A first step of dissolving starting materials Zn (NO 3) 2 .6H 2 O and Mn (NO 3) 2 .XH 2 O with deionized water; A second step of adding and dissolving the citric acid so that a molar ratio of the solution of the first step and the citric acid is 3: 1; A third step of mixing nitric acid (HNO 3) such that the pH of the second step solution is 1 to 2; A fourth step of dropping the silica-sol while stirring the solution of the third step to obtain a uniform precursor; A fifth step of synthesizing the green phosphor by stirring the solution of the fourth step for a predetermined time, burning the burned powder in a heater, and calcining and cooling the powder in an alumina crucible in an air or oxygen atmosphere; A sixth step of reacting the green phosphor in a reducing atmosphere of nitrogen and hydrogen; Method for producing a phosphor, characterized in that consisting of. The method according to claim 1, In the fifth and sixth step, the temperature of the air atmosphere and the reducing atmosphere is 800 to 1000 ℃, the temperature of the oxygen atmosphere and the reducing atmosphere is 300 to 900 ℃ characterized in that the manufacturing method of the phosphor. The method according to claim 2, The light emission intensity of the green phosphor increases as the amount of manganese or the heat treatment temperature or the amount of silica-sol added increases. The method according to claim 3, The amount of the manganese is a phosphor manufacturing method, characterized in that x is 0.02 to 0.08 based on the green phosphor (Zn ₂ - _X Mn _X SiO ₄ ). The method according to claim 4, The green phosphor is a method for producing a phosphor, characterized in that the single phase compound. The method according to claim 5, The particle size of the green phosphor formed after the heat treatment is characterized in that the phosphor of 200 to 600 nm. The method according to claim 1, Deionized water of the first step is a method for producing a phosphor, characterized in that the tertiary distilled water. The method according to claim 1, Reducing atmosphere of the six steps is a method of producing a phosphor, characterized in that consisting of 96% nitrogen, 4% hydrogen. The phosphor formed by the phosphor manufacturing method of any one of Claims 1-8.

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