TW200427829A - Novel preparation of sulfide phosphors - Google Patents

Abstract

This invention provides a novel preparation of sulfide phosphor. The phosphor comprises a sulfide host and a phosphor center. The preparation comprises steps of (a) dry blending sulfide host powder, activator powder functioning as the phosphor center and fluxing agent for decreasing the sintering temperature to form a precursor, in which the sulfide host powder comprises 0-100 weight % of lump powder and 0-100 weight % of seed powder, and (b) performing calcination of the precursor obtained from the step (a) to produce the phosphor.

Description

200427829 ⑴ Rose ;, description of the invention (the description of the invention should state: the technical field to which the invention belongs, the prior art, the content, the embodiments and the drawings are briefly explained) 1. The technical field to which the invention belongs The present invention is mainly related to the preparation of a phosphor The method, in particular, relates to a method for preparing a sulfide phosphor using a seed crystal flux method. 2. The prior art fluorescent powder system is widely used in many light-emitting objects around daily life, such as television image tubes, monitor image tubes, observation image tubes, radars, flying spot scanner image sensitizers, and photocopier image tubes. , Vacuum fluorescent display tubes, plasma displays, lighting equipment, traffic signs, fluorescent panels, sensitization paper, and light-emitting diodes, etc. In recent years, due to people's concerns about the display quality such as resolution and brightness, and lighting effects The requirements have generally increased, and research on fluorescent powder has also received considerable attention. Phosphor materials are generally divided into organic phosphors and inorganic phosphors, where _ — inorganic phosphors include a luminous center formed by a host material (Host) and an appropriate activator (Dopant, also known as Activator). . Currently, the parent materials commonly used in the industry are group II-VI ionic compounds, such as calcium (Ca), total (Sr), barium (Ba) (Group IIA), or zinc (Zn), An ionic compound formed by cadmium (Cd), mercury (Hg) (Group IIB), sulfur (S), and selenium (Se) (Group VI). The type of activator determines the luminous color. Generally, the activators commonly used in the industry are manganese (Μη), copper (Cu), silver (Ag), and lanthanides such as europium (Eu), europium (Sm), and europium (Tb). Transition metal ion or rare earth element ion. The luminescence mechanism of this kind of phosphor is caused by the electrons in the outer layer of the luminous center to be migrated by an accelerated acceleration of the electrons, so that the outer layer electrons are elevated to the energy level of the crystalline conduction band of the parent material, forming free electrons, and the luminous center is also ionized. , And finally free electricity (2) 200427829 ions and ionization 1 It is currently known: 082110013 "The system first prepares an encapsulated organic spheroid solution to the slurry and an aqueous alloy to obtain the luminescence, and its production of cubes, bromide: Medium The selected particle-free reaction is not easy to operate in order to generate a pure particle or pure particle product with the Republic of China. The method is to form a layer on a hard son, and the other method is to quit the job. Purpose. The light-emitting center is combined with ′ to release the energy step difference in the form of light. Diverse methods for preparing phosphors: · For example, the patented luminescent powder composition of the Republic of China and its preparation method. "The uncovered method contains one or more calcined pure particles in an aqueous or water-containing liquid, and then contains at least A stable solution of a metal chelate, and controlling an appropriate pΗ value and temperature so that at least a metal oxide is deposited on the particle, and the particle is calcined to obtain a compound; and the Republic of China Patent No. 087119146 " The "fluorescent method" reveals that carbon microparticle materials with a rhenium microstructure are mixed with a group of organic salts composed of chloramphenicol, nitrate, and their crystalline mixtures, and heated at 200 to 800 ° C to make them The carbon is micro-formed into an interlayer compound, and the interlayer compound is then treated with a release agent to impregnate the luminescent inorganic compound particles of the carbon material. Patent No. 08211013 is provided in a water-soluble reaction solution so that the generation reaction occurring in the reaction solution adheres to the core, and then the product is recovered from the aqueous solution. The step of recovering the aqueous solution not only has a low product purity, but the ROC Patent No. 087119146 is mixed with the inorganic salt and heated to make the compound between the carbon particles. Although this method eliminates the recovery step, it removes the agent. The steps still require complicated preparation procedures. The present invention is devoted to the development of a novel method for preparing phosphors with simple operation, uniform average particle size and excellent properties. 200427829

(3) III. Summary of the Invention The object of the present invention is to provide a method for preparing a phosphor. The phosphor includes a sulfide precursor and a luminescent center. The method includes the following steps: (a) dry-mixing the sulfide precursor powder A precursor that can be used as the activator powder of the luminous center and the flux powder that can reduce the sintering temperature, wherein the sulfide precursor powder contains 0 to 100% by weight of block powder and 0 to 100% by weight of seed crystal powder ,·and

(b) the precursor before step (a) to obtain the phosphor. 4. Embodiments The present invention relates to a novel and easy-to-use method for preparing phosphors, which can produce products with uniform average particle size and excellent properties. In particular, the method of the present invention uses the seed crystal assisting method to A fluorescent body is prepared. The fluorescent body includes a sulfide matrix and a light-emitting center. The simplified process is shown in Figure 1. The method includes the following steps:

(a) A precursor made of dry-mixed sulfide precursor powder, activator powder that can be used as a luminescent center, and flux powder that can reduce the sintering temperature, wherein the sulfide precursor powder contains 0 to 100% by weight of a bulk material. Powder and 0 to 100% by weight of seed powder; and (b) calcining the precursor of step (a) to obtain the phosphor. The term "phosphor" used in the present invention refers to a luminous body comprising a luminous center formed by a host (Host) and an appropriate activator (Dopant, also called Activator). _ The "sulfide phosphor" referred to in the present invention refers to a phosphor containing a sulfur-containing compound as a precursor, preferably a sulfide of group II-VI, -9- 200427829

For example, (Cd), which is the ionic junction phase in the process examples of the material elements such as hafnium ion, and the auxiliary ion, gasification temperature, and low-temperature calcination system. Mole% of parent powder (4), such as calcium (Ca), total (Sr), barium (Ba) (IIA group) or zinc (Zn), mercury (Hg) (IIB group) vulcanization The substance is a fluorescent substance of the matrix, and more preferably a phosphor of zinc sulfide. The term "activator" as used in the Ming refers to the light emitting center in the phosphor, for example, manganese (Mn), copper (Cu), silver (Ag), lanthanide (Eu), thorium (Sm) , Tb transition metal ions or rare earth elements. Preferably, the activator is a manganese ion provided by manganese oxide. Ming-Suo's "fluxing agent" refers to a substance that can reduce the sintering temperature in sintering fluorescent light. In one embodiment of the present invention, the co-solvent is an ionic compound. When the compound serving as the co-solvent is melted, the heat of fusion released by the compound can provide the energy for the burning transition of the phosphor, so that the sintering temperature of the phosphor reduce. For example, the flux is lead, calcium, magnesium, potassium, barium, sodium, lithium, tin, zinc, or titanium compounds. Preferably, it is lithium chloride, sodium chloride, potassium potassium chloride, potassium fluoride, fluoride Lithium or barium fluoride. According to the present invention, at high times, the luminosity of the phosphor obtained by adding sodium chloride is better; but at the time of firing, the luminosity of the phosphor obtained by adding lithium chloride is better, which is soluble in both. Different points' also apply to different simmering conditions. In the present invention, step (a) is to form a precursor by dry-blending the sulfide precursor powder, the activator powder, and the flux powder. In this specific embodiment, the content of the activator in the precursor is i; the content of the flux in the precursor is mol%. The sulfide powder is from 0 to 100% by weight of the bulk powder and from 0 to ^ 00% by weight, the bulk powder reacts with the activator on the seed crystal to form the desired

-10- 200427829

(5) Fluorescent body; preferably, it contains 100% by weight of block powder, 99% by weight of block powder and 1% by weight of seed crystal powder, 90% by weight of block powder and 10% by weight Seed crystal powder, 60% by weight block powder and 40% by weight seed crystal powder or 100% by weight seed crystal powder; more preferably, it contains 99% by weight block powder and 1% by weight seed Crystal powder has the strongest luminous intensity. As the proportion of seed powder increases, excessive seed crystals will generate heterogeneous phases such as MnS04 and ZnO, which is not conducive to the emission of phosphors. In a specific embodiment of the present invention, the average particle diameter of the bulk powder is 0.1 micrometer to 10 micrometers; the average particle diameter of the seed crystal powder is 1 nanometer to 10 nanometers. According to the present invention, the seed crystal powder can be obtained by grinding a sulfide powder having a large average particle diameter. In one embodiment of the present invention, the seed crystal powder can be obtained by colloid co-precipitation method, and then obtained by grinding. On the other hand, in order to make the components contained in the precursor more uniform and more conducive to the reaction, a step of grinding the precursor may be further included. According to the present invention, step (b) is to calcine the precursor and sinter the precursor to obtain the phosphor, and the temperature may depend on the composition of the precursor. According to a specific embodiment of the present invention, the calcining temperature may be 40 ° C. to 1000 QC, preferably 600 ° C. to 1000 ° C., and more preferably 900 ° C. On the other hand, the calcination process is preferably It is performed in an oxygen-free environment, and more preferably, it is performed in a hydrogen reducing environment. The luminous intensity of a phosphor is closely related to its crystal structure. When the crystal structure changes from a cubic phase to a hexagonal phase, its fluorescence The luminous intensity of the light body will increase. The method of the present invention can increase the hexagonal phase transition rate of the obtained phosphor and increase the luminous intensity. With different proportions of seed crystal powder, -11-(6) 200427829

Assistance is as follows: a, 1, 2 3 4 5 6 7 8 and different calcination temperatures, which can produce fluorescent peaks of different properties. ^ In the preferred embodiment of the present invention, ^% zinc sulfide seed crystals are used. :. 9% by weight of zinc sulfide block powder was used as a base material, and 1% by mole was added. The manganese oxide powder and 1 mole% sodium oxide powder became the precursors, and the fluorescent body with good luminous intensity can be obtained after the slope of C. In order to make the application more convenient, the invention may further include a grinding step after preparing the phosphor to obtain a phosphor powder.

I

* \ List 1 example to explain the present invention in detail, but it does not mean that the present invention is limited to the content disclosed by these examples. The average particle diameters prepared in advance are about 4 nanometers or 0 丨 microns to 10 micrometers < zinc sulfide powder as seed crystal powder and block powder, and added

-12- 1 Wu Er% manganese oxide powder and 1 Mo Er% lithium gas powder or sodium chloride powder are mixed to form a precursor and ground, calcined in a hydrogen reducing atmosphere for 2 hours and then ground again to obtain zinc sulfide: manganese (ZnS: Mn) phosphor powder. 2 Diffraction analysis of the obtained powder with X-rays to analyze the hexagonal crystal phase transition rate, the calculation formula is as follows: 3 Μβ / Μα = 0.0968 * Ιβ / Ια 4 /, and / 3 is τς cubic phase ; Α is a cubic phase; Μρ / Μα is a sufficient weight ratio of a stone phase to an α 5 phase; ϊβϊα is an intensity ratio of (100) cold to (200) α. 6 On the other hand, the obtained fluorescent powder was excited with a photoluminescence spectrometer 7 at a light wavelength of 343 nm 8 ′, and the integrated intensity analysis was performed. The ratio of seed crystal powder, calcination temperature, flux composition, and hexagon in 9 flooding materials 200427829

The results of the 相比 crystal comparative example and the integrated fluorescence intensity are shown in Table 1: Table 1: Comparison of burn temperature-seed powder _ hexagonal crystal comparative example (%) integrated intensity (au ·) final ratio (Wt ° / o) 1 Mole% 1 Mole% 1 Mole% 1 Mole% Lithium chloride NaCl Lithium chloride Steel 400 ° C-0 wt% 0 0 0 0 400 ° C-1 wt% 0 0 0 0 400 ° Cl〇wt% 0 0 0 0 400〇C-40 wt% 0 0 0 0 400 ° C-100wt% 35.2 41.9 3363 600 ° C-〇wt% 9 63 87095 ~ 38549 ~ 600 ° C-1 wt% 10.8 8.7 102 184 39056 600 ° C-10wt% 12.8 10.9 70174 22357 600 ° C-40 wt% 42.9 39.6 65516 9685 600 ° C-100wt% lbo 100 16290 10418 800 ° C-〇wt% 42.3 3Z6 149865 208881 800 ° C-1 wt% 25.6 51.2 188685 467885 800 ° C-10wt% 73.3 35 95901 70039 800 ° C-40wt% 63 41.5 73681 52865 800 ° C-100wt% 100 100 13609 11469 900 ° C-0wt% 45.7 46.3 237765 419719 900 ° C- 1 wt% 42.2 58.2 258539 507329 900 ° C-10wt% 78.8 69.7 52507 80334 900 ° C-40 wt% 49.7 27.4 42334 4364 900 ° C-100wt% 100 100 19928 21569 1000 ° C-0wt% 100 51 168952 ^ 194951 ~ 1000 ° C-1 wt% 100 70 219944 335182 1000 ° C-10wt% 100 100 41403 47113 1000 ° C-40wt% 100 100 2650 29920 1000 ° C-100 wt% 100 100 28732 30512 As can be seen from the results in Table 1, when the sintering temperature is 400 ° (:, the proportion of seed crystal powder is 100wt · Except for the phase transformation of% of the samples, the other samples could not be detected-the square crystal phase was detected. The reason is presumed that the seed crystal powder has a lower melting point and a faster crystal growth rate, so phase transfer can occur at a lower temperature. ; When the sintering temperature is higher than 600 QC, phase transformation occurs in all the samples, among which the seed crystal is -13-200427829.

样品 When the sample with a proportion of 100 wt% is burned at 600 Qc, the crystal phase has been completely transformed into a hexagonal crystal phase, which is much lower than the phase transition temperature of traditional block materials of 10 ° C. The proportion of the hexagonal crystal phase increases with the increase of the sintering temperature and the proportion of seed crystal powder, but it does not increase correspondingly. For example, when the calcination temperature is 800 '° C and 900 QC, the proportion of seed crystal powder increases. When it is 40% by weight, the phase transfer rate is decreased. It can be seen that excessive seed crystal powder is not conducive to hexagonal phase transformation when sintered at high temperature. On the other hand, when it is calcined at 400 ° C, if the proportion of seed crystal powder is too high, it will form MnS04 and ZnO heterophases, which is not conducive to the luminous intensity of the phosphor; at higher temperatures (> 600 ° C) When burned, it can be seen that when the proportion of seed crystals is, the sample's luminous intensity is the strongest. According to the luminous intensity of the sample, the preferred ratio of seed crystal powder can be summarized as: lwt% > 0wt% > 10wt% > 40wt% > l 〇〇wt%. Observe the effect of the type of flux again. When the calcination temperature is 1000 ° C, the crystal phase of the sample is completely converted to hexagonal phase. However, the sample of sodium chloride flux is added to the lower When the proportion of seed crystal powder, the cubic crystal phase still exists. Therefore, it can be known that under high temperature scorching conditions, the phase transfer rate of the sample with the chlorinated flux is higher than that of the sample with the sodium chloride co-solvent. It is inferred that the melting point (614 ° C) of the chloride surface is lower than the melting point (801 ° C) of the chlorinated rhodium, so that the phase transition temperature of the sample to which the lithium chloride flux is added is lower, and the phase transition rate is higher. In terms of luminous intensity, when the proportion of seed crystal powder is low (0 wt% and 1 wt%), the sample of emulsified steel is added at 800. Above C, there is better luminous intensity production. At temperature (600 ° C), the samples with lithium chloride added have better luminous intensity production: high proportion of seed crystals (10 wt%, 40 wt% and 100 wt. %), The gasification-14-(9) (9) 200427829 nanometer sample is added at high temperature (greater than or signed from (Wen Yuci Temple at 90. 00). There is a better luminous intensity when burned, but at 800 ° C 以下 温 炮 烧 #, the sample with added chloride has better luminous efficiency. In general, the addition of chlorine ... solvent helps to increase the luminous intensity when sintered at low temperature; but when it is fed at high temperature, it vaporizes The addition of the nano-flux helps to emit light instead. It is inferred that the melting point of the two is so high that the melting point of the coffee is higher than that of the sodium chloride sample. Interestingly, when the "powder ratio is 4l wt% and the sodium sulfide is added before the precursor is calcined at 900 ° C, the sample has the best luminous intensity. The X-ray diffraction results of this sample are shown in Figure 2. The results of the photoluminescence spectrometer are shown in Figure 3. The particle size estimates were obtained by measuring with an inductively coupled plasma quality analyzer. As shown in Figure 4, you can know that the particle size is quite uniform. You can see the scanning electron micrographs and transmission electron micrographs at the same time. Figure 5 and Figure 6 show the electron appearance. The radiograph is also shown in Fig. 7 ', and the phosphor prepared by the present invention is relatively close to the edge of the spectral trajectory at the position of the chromaticity coordinate chart, and it can be seen that its color purity is good. The above embodiments are only to illustrate the principle of the present invention and its effects. Therefore, instead of limiting this month, the modifications and changes made by those skilled in the art to the above-mentioned embodiments still * remember the spirit of the present invention. The scope of the rights of the present invention should be listed in the patent application park described later Schematic description ^ Figure 1 Table 7F Flow chart of the method for preparing sulfide phosphors according to the present invention. Figure 2 shows the 乂 -ray diffraction pattern of phosphor powders prepared according to the method of the present invention. -15 -200427829 (ίο), continuation Figure 3 shows the result of phosphor powder produced according to the method of the present invention excited by a photoluminescence spectrometer at a wavelength of 343 nm. Figure 4 shows the result obtained by the method of the present invention. Phosphor powder measured by induction coupled plasma mass spectrometer The results are shown in Fig. 5. Table 5> Scanning electron micrograph of the phosphor powder produced by the method of the present invention. Fig. 6 shows the penetration of the phosphor powder produced by the method of the present invention. Electron microscopy shoulder. Figure 7 shows an electron diffraction transmission electron micrograph of a phosphor powder prepared according to the method of the present invention. -16-

Claims (1)

200427829 Patent application and patent application 1. A method for preparing a phosphor, the phosphor comprising a sulfide precursor and a luminescent center, the method comprises the following steps: (a) dry-mixed sulfide precursor powder, which can be used as The activator powder of the luminous center and the flux powder capable of reducing the sintering temperature form a precursor, wherein the sulfide precursor powder includes 0 to 100% by weight of block powder and 0 to 100% by weight of seed powder; and (b ) Burn the precursor of step (a) to obtain the phosphor. 2. The method according to item 1 of the patent application, wherein the sulfide is zinc sulfide. 3. The method according to item 1 of the scope of patent application, wherein the average particle diameter of the block powder is 0.1 micrometer to 10 micrometers. 4. The method according to item 1 of the patent application scope, wherein the average particle size of the seed crystal powder is 1 nm to 10 nm. * — 5. The method according to item 1 of the scope of patent application, wherein the sulfide powder contains 100% by weight of block powder. 6. The method according to item 1 of the patent application scope, wherein the sulfide powder contains 99% by weight of block powder and 1% by weight of seed crystal powder. 7. The method according to item 1 of the scope of patent application, wherein the sulfide powder contains 90% by weight of block powder and 10% by weight of seed crystal powder. 8. The method according to item 1 of the scope of the patent application, wherein the sulfide powder contains 60% by weight of block powder and 40% by weight of seed crystal powder. 9. The method according to item 1 of the scope of patent application, wherein the sulfide powder contains 100% by weight of seed crystal powder. 200427829 10. The method according to item 1 of the scope of patent application, wherein the seed crystal powder is prepared by grinding the sulfide powder obtained by the co-precipitation method. 11. The method according to item 1 of the scope of patent application, wherein the activator is a group consisting of a transition metal element ion compound and a rare earth element ion compound. 12. The method according to item 11 of the application, wherein the activator is a manganese ion provided by manganese oxide. 13. The method according to application, patent scope item 1, wherein the ratio of the activator to the precursor is 1 mole%. 14. The method according to item 1 of the patent application, wherein the flux is an ionic compound. 15. The method according to item 14 of the application, wherein the flux is selected from the group consisting of lithium chloride, sodium chloride, magnesium chloride, potassium chloride, potassium fluoride, lithium fluoride, and barium fluoride. — ~ 16. The method according to item 1 of the scope of patent application, wherein the ratio of the flux to the precursor is 1 mole%. 17. The method according to item 1 of the scope of patent application, wherein the firing temperature of step (b) is 400 ° C to 1000 ° C. 18. The method according to item 17 of the scope of patent application, wherein the sintering temperature of step (b) is 600QC to 1000 ° C. 19. The method according to item 1 of the scope of patent application, wherein the step (b) of sintering is performed in an oxygen-free environment. 20. The method according to item 19 of the scope of patent application, wherein the sintering of step (b) is performed in a hydrogen reducing environment. 200427829 21. The method according to item 1 of the patent application scope further comprising a step of grinding the precursor after step (a). ‘22. The method according to item 1 of the scope of patent application, which further comprises a grinding step after step (b) to obtain a phosphor powder. 23. —A method for preparing a phosphor, the phosphor comprising a zinc sulfide precursor and a luminescent center, the method comprises the following steps: (a) dry mixing zinc sulfide precursor powder, 1 mole% oxidation A precursor made of manganese and 1 mole% < sodium chloride, wherein the zinc sulfide precursor powder comprises 99% by weight of block powder and 1% by weight of seed crystal powder; and, (b) sintered at 900QC (A) Precursor to obtain the phosphor. 24. The method according to item 23 of the scope of patent application, wherein the average particle size of the block powder is 0.1 to 10 microns. 25. The method according to item 23 of the scope of patent application, wherein the seed crystal powder has an average particle size of 1 nm to 10 nm.