KR100289193B1 - Manufacturing method of phosphor - Google Patents

Abstract

The present invention relates to a method for producing a phosphor having a simple manufacturing process through particle size and shape control by a liquid phase reaction method.

In the method of manufacturing the phosphor according to the present invention, Zn _2-x Mn _x SiO ₄ is a zinc nitrate (Zn (NO ₃ ) ₂ 6H ₂ O), silicic acid (Silicic acid) and manganese sulfate ( MnSO ₄ ) to prepare a precursor solution for weighing and dissolving them in water and stirring; Adding ammonia water to the precursor solution in a ratio of NH ₃ OH: Zn ²⁺ = 5: 1 to 3: 1, and refluxing for 3 to 7 hours; A precipitate forming step of forming a precipitate by leaving the solution after reflux at room temperature; A separation step of separating the formed precipitate by filtration or the like; A drying step of drying the obtained precipitate; And firing the dried precipitate in a temperature range of 900 to 1300 ° C.

Therefore, there is an effect of providing a method for producing a phosphor having a simple manufacturing process through particle size and shape control.

Description

Manufacturing method of phosphor

The present invention relates to a method for producing a phosphor. More specifically, the present invention relates to a method for producing a phosphor having a simple manufacturing process through particle size and shape control by a liquid phase reaction method.

In recent years, the development of portable information devices has been actively progressed, and the application range thereof has been widened, and as a means of recognizing these portable personal information devices, development of lightweight and small display devices such as plasma display devices has been further demanded. Display devices generally convert electrical signals into visible light so that the human body can recognize characters or figures. Most of the phosphors stimulated by electrical signals cause light emission in the visible band. As a result, the user may visually recognize the displayed character or figure.

Therefore, in order to develop a smaller and lighter display device, there is a demand for the development of a phosphor having superior light emission characteristics.

In particular, in the case of zinc silicate phosphors, development has already been completed and mainly used for commercial use in cathode ray tubes and plasma display devices. The zinc silicate phosphor is usually represented by Zn ₂ SiO ₄ : M or Zn _2-x M _x SiO ₄ , wherein only manganese is used as M (brand name P1 phosphor) according to M as an activator, or manganese or arsenic Are used (trade name P39 phosphor), or those containing further active agents such as manganese, arsenic, and antimony (Japanese Patent Application No. 57-34620). In addition, these zinc silicate phosphors using manganese and arsenic as activators have also been used for lamps due to their excellent luminescence properties and long afterglow properties.

Meanwhile, Korean Patent Publication No. 86-1883 discloses a zinc silicate phosphor that uses antimony or bismuth to suppress the use of arsenic having toxicity and pollution problems as an activator and to have excellent luminescence properties. However, zinc disilicate phosphors also have some differences in toxicity and pollution, but it can be said that these antimony and bismuth may still exhibit toxicity and pollution problems in long-term use.

In addition, Korean Patent Publication No. 86-1896 discloses manganese, arsenic, etc., in which zinc is partially substituted with one of barium, calcium, strontium, and sodium in the zinc silicate phosphor, as an activator and a study active agent. A zinc silicate phosphor capable of reducing burning of phosphors (a phenomenon in which part of the phosphors is oxidized or lost due to scanning of the cathode lines at the same position for a long time, and thus luminance staining occurs) is described. However, this also provides the purpose of alleviating the burning phenomenon, but there are problems of toxicity and pollution due to the use of arsenic as an activator, and the luminescence property is rather deteriorated because the brightness is slightly reduced due to the addition of arsenic. There was a problem.

On the other hand, many studies have been conducted to improve the characteristics of manganese as an activator. Especially, in order to be used as a display phosphor, high luminous luminance, excellent color purity, and appropriate decay time are required. . Recently, attention has been focused on the study of new synthetic methods and the optimization of the type and concentration of activators for improving the properties of zinc silicate green phosphors using manganese as an activator. On the other hand, research of the fluorescent substance for display is A. Morel et al. Reported that after increasing manganese activator concentration in zinc silicate (ZnSiO ₄ ) matrix, the afterglow was shortened. Holding it.

In general, the solid phase reaction method has been mainly used in the production of conventional zinc silicate green phosphor. However, the conventional solid phase reaction method requires a high firing temperature and a long firing time, and has a disadvantage in that particle shape and size are difficult to control.

In order to solve these drawbacks, in recent years, research has been made at home and abroad to produce zinc silicate green phosphor having excellent properties by hydrothermal synthesis, sol-gel, and thermal spraying as a new synthesis method in addition to the solid state reaction method. However, these synthesis methods have some effects such as controlling the shape and size of particles and improving the luminance of light emitted. However, these synthesis methods have a disadvantage in that they require a lot of effort and cost for practical application due to the complicated manufacturing process.

An object of the present invention is to overcome the disadvantages of the solid phase reaction method, to provide a method for producing a phosphor using a liquid phase reaction method is relatively simple manufacturing method.

Another object of the present invention is to provide a method for producing a phosphor having a simple manufacturing process through particle size and shape control by a liquid phase reaction method.

1 is a graph showing the emission peak intensity under 254 nm excitation when the firing temperature is changed to a range of 900 to 1250 ° C. in the preparation of a Zn _1.9 Mn _0.1 SiO ₄ green phosphor sample according to the present invention.

2 is a graph showing the emission peak intensity under 147 nm excitation when the firing temperature is changed to a range of 900 to 1250 ° C. in the preparation of a Zn _1.9 Mn _0.1 SiO ₄ green phosphor sample according to the present invention.

3 is a graph showing the change of X-ray diffraction (XRD) peak when the firing temperature is changed to a range of 900 to 1250 ° C in the preparation of a Zn _1.9 Mn _0.1 SiO 4 green phosphor sample according to the present invention.

4 is a graph showing the relative emission intensity according to the concentration of manganese (Mn) (0.01 to 0.2) in the preparation of Zn _2-x Mn _x SiO ₄ green phosphor sample according to the present invention.

5 is a graph showing the change in color purity according to the concentration (0.01 to 0.2) of manganese (Mn) in the preparation of the Zn _2-x Mn _x SiO ₄ green phosphor sample according to the present invention.

Figure 6 is a graph of the particle size distribution measured by measuring the particle size according to the firing temperature change in the preparation of Zn _1.98 Mn _0.02 SiO ₄ green phosphor sample according to the present invention using a particle size analyzer (PSA).

7 to 10 show the firing temperatures of 900 ° C. (Fig. 7), 1000 ° C. (Fig. 8), and 1100 ° C. (Fig. 9) in the preparation of Zn _1.98 Mn _0.02 SiO ₄ green phosphor sample according to the present invention. And scanning electron micrographs measuring the change in the size of the phosphor particle size with increasing to 1200 ° C. (FIG. 10).

In the method of manufacturing the phosphor according to the present invention, Zn _2-x Mn _x SiO ₄ is a zinc nitrate (Zn (NO ₃ ) ₂ 6H ₂ O), silicic acid (Silicic acid) and manganese sulfate ( MnSO ₄ ) to prepare a precursor solution for weighing and dissolving them in water and stirring; Adding ammonia water to the precursor solution in a ratio of NH ₃ OH: Zn ²⁺ = 5: 1 to 3: 1, and refluxing for 3 to 7 hours; A precipitate forming step of leaving the solution after reflux at room temperature to form a precipitate; A separation step of separating the formed precipitate by filtration or the like; A drying step of drying the obtained precipitate; And a firing step of firing the dried precipitate in the temperature range of 900 to 1300 ℃.

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

The method for producing a phosphor according to the present invention is to facilitate the control of the size and shape of the phosphor particles obtained by the liquid phase reaction method, in particular to increase the emission intensity and color purity, to enhance the emission intensity, and to have a uniform particle size distribution It can manufacture.

In the present invention, first, in the precursor solution preparation step, Zn _2-x Mn _x SiO ₄ is x-0.01 to 0.2 so that zinc nitrate (Zn (NO ₃ ) ₂ 6H ₂ O), silicic acid and manganese sulfate (MnSO ₄ ) is weighed and liquefied by dissolving them in water. As raw materials, zinc nitrate (Zn (NO ₃ ) ₂ 6H ₂ O), silicic acid and manganese sulfate (MnSO ₄ ) may be used for the production of zinc silicate green phosphors. Of course, these raw materials may be used for other raw materials for controlling the luminescent properties of the phosphor, in particular manganese and the like to function as an activator, other metals in addition to manganese can be used as the activator is common in the art It is obvious that it can be easily understood by those who have knowledge.

In the subsequent reflux step, ammonia water was added to the precursor solution in a ratio of NH ₃ OH: Zn ²⁺ = 5: 1 to 3: 1, and refluxed for 3 to 7 hours, and sufficient reaction occurred through reflux. By making it possible to obtain a phosphor powder of a uniform size and shape.

Subsequently, in the precipitate forming step, the solution after refluxing is left at room temperature to form a precipitate. When the solution is stabilized by not applying impact or agitation, the precipitate precipitates as it naturally forms. The formed precipitate is separated by filtration or the like, dried by heating to a temperature of about 50 ° C. in a dryer or the like. Drying is such that bubbles or the like are not formed in the phosphor formed after firing in the firing step, and phosphor powder having a uniform size and shape can be obtained by uniform firing.

Subsequently, the dried precipitate is fired in a firing furnace at a temperature in the range of 900 to 1300 ° C. to become a phosphor. In particular, the firing may be fired in air by charging into an alumina boat or the like, and may be substantially achieved by slowly quenching in the electric furnace for about 4 hours in the above temperature range.

Hereinafter, preferred embodiments and comparative examples of the present invention will be described.

The following examples are intended to illustrate the invention and should not be understood as limiting the scope of the invention.

[Examples 1 to 6]

Powder of zinc nitrate (Zn (NO ₃ ) ₂ 6H ₂ O), silicic acid (2.7636 g) and 0.5981 g of manganese sulfate (MnSO ₄ ) were precisely weighed to prepare a green phosphor with a manganese (Mn) content of 0.1. The mixture mixed in the form was dissolved in water. Then, ammonia water was added to NH ₃ OH: Zn ²⁺ = 4: 1, and refluxed for 5 hours to prepare a precursor solution of Zn _2-x Mn _x SiO ₄ . After refluxing, the precipitate formed by standing at room temperature was filtered out using a conventional microfilter and dried for 10 hours in a drier maintaining a temperature of 50 ℃. The dried precipitate was charged into an alumina boat and placed in an electric furnace, followed by 900 ° C (Example 1), 1000 ° C (Example 2), 1100 ° C (Example 3), 1150 ° C (Example 4), 1200 ° C (Example 5) and firing at 1250 ° C. (Example 6) for 4 hours with different firing temperatures to obtain the desired phosphor, and the emission peak intensity of the obtained phosphors was 254 nm excited (FIG. 1) and 147 nm excited (first). 2 degrees) and graph it. X-ray diffraction (XRD) peaks of the obtained phosphors are also shown in FIG. As shown in FIG. 1, as the firing temperature is increased from 900 ° C to 1250 ° C, it can be seen that the relative emission intensity increases more than four times, and the FWHM (Full Width at Half Maximum) value of the emission peak is 84.9. It was confirmed that the color purity was greatly improved by a sharp decrease from 45.3 nm to 45.3 nm. In Figure 2 it can be seen that a similar trend. Here, the large decrease in the luminescence peak intensity at the firing temperature of 1100 ° C. or less indicates that the phosphor powder is not completely crystallized and an unreacted substance is present so that these unreacted phases act as inhibitors of luminescence.

In addition, as shown in FIG. 3, the peak strength of the crystal phase was increased as the firing temperature was increased from 900 ° C to 1250 ° C. At a low firing temperature of 1000 ° C., a peak appearing as an unreacted impurity crystal phase was found in the vicinity of 2θ = 36 °.

Example 7

A phosphor was obtained in the same manner as in Example 1 except that the content of manganese as an activator was adjusted to a range of 0.01 to 0.2, and the calcination temperature was set at 1200 ° C., and the obtained phosphor was 254 nm and 147 nm in wavelength. Relative luminescence intensity was measured according to the concentration of manganese of the phosphor obtained by emitting light using the excitation source having the result, and the result is shown in FIG. As shown in FIG. 4, it was confirmed that the light emission intensity was different according to the wavelength of the excitation source, and thus, it was confirmed that various phosphors could be manufactured according to the wavelength of the excitation source by controlling the content of manganese. . In the case of using an excitation source having a wavelength of 254nm, the content of manganese may have the best emission intensity in the vicinity of 0.08, and when the manganese content is increased to 0.16 or more, the emission intensity may be drastically reduced. In addition, in the case of using an excitation source having a wavelength of 147 nm, the content of manganese may have the best luminous intensity in the vicinity of 0.02, and it may be confirmed that the luminous intensity may drop rapidly at 0.10. In addition, as shown in FIG. 5, the change in color purity according to the content of manganese was measured. As the content of manganese increased, the color purity improved from 62.9% to 74.8%.

Example 8

The amount of manganese as an activator was adjusted to 0.02, and the firing temperature was increased to 900 ° C (Fig. 7), 1000 ° C (Fig. 8), 1100 ° C (Fig. 9) and 1200 ° C (Fig. 10). Except for the Zn _1.98 Mn _0.02 SiO ₄ green phosphor sample was obtained in the same manner as in Example 1 except that the change in the size of the phosphor particle size according to the firing temperature was taken by scanning electron micrograph. As shown in these electron micrographs, it was confirmed that the size of the phosphor particle was somewhat increased as the firing temperature was increased from 900 ° C. to 1200 ° C., and the particle shape was close to a spherical shape. Particle size of the phosphor fired at a temperature of 1200 ℃ mainly consists of relatively small particles of 2 to 3μm, it was confirmed that the aggregated particles of about 5μm size is also found. In addition, FIG. 6 shows the PSA particle size distribution with respect to firing temperature, and the average particle size increases with increasing firing temperature. Particularly, when firing at 900 ℃, the particle size was slightly decreased than before firing. It is believed that particle shrinkage occurred as the organic matter added during the liquid phase reaction separated from the particles with the rise of temperature at the beginning of firing. It is believed that the crystallization gradually becomes larger particles through the growth of bonding of smaller particles as is increased to more than 1000 ℃. It was confirmed that a phosphor mainly composed of particles having a size of 2 to 3 μm was obtained at a calcination temperature of 1200 ° C., which is consistent with the scanning electron micrograph of FIG. 10.

As a result of the synthesis of the above embodiments, it is possible to obtain phosphor particles shaped into particles of a size and a circular shape, and in particular, by controlling the content of manganese as an activator, phosphors having different emission intensities depending on the wavelength of the excitation source. It could be confirmed that manufacturing is possible.

Therefore, according to the present invention, it is effective to provide a method for producing a phosphor having a simple manufacturing process through particle size and shape control.

Although the present invention has been described in detail only with respect to the described embodiments, it will be apparent to those skilled in the art that various modifications and variations are possible within the technical scope of the present invention, and such modifications and modifications are within the scope of the appended claims.

Claims (1)

In Zn _2-x Mn _x SiO ₄ , x is 0.01 to 0.2 so that zinc nitrate (Zn (NO ₃ ) ₂ 6H ₂ O), silicic acid and manganese sulfate (MnSO ₄ ) are weighed and dissolved in water. Preparing and stirring a precursor solution; Adding ammonia water to the precursor solution in a ratio of NH ₃ OH: Zn ²⁺ = 5: 1 to 3: 1, and refluxing for 3 to 7 hours; A precipitate forming step of forming a precipitate by leaving the solution after reflux at room temperature; A separation step of separating the formed precipitate by filtration or the like; A drying step of drying the obtained precipitate; And firing the dried precipitate in a temperature range of 900 to 1300 ° C .;