TW201319220A - Method for synthesizing oxynitride phosphors - Google Patents

Abstract

A method for synthesizing oxynitride phosphors is provided. The method includes steps of: firstly synthesizing silicate phosphors by chemical co-precipitation reaction, and then mixing silicate phosphors with silicon nitride to synthesize oxynitride phosphors by solid-state reaction. The oxynitride phosphors synthesized by the present invention can provide a crystallinity apparently better than that of oxynitride phosphors synthesized by traditional solid-state reaction (SSR) or traditional 2-step solid-state reaction (SSR2), and also can provide higher quantum efficiency and thermal stability. Meanwhile, the size and evenness of particles of oxynitride phosphors synthesized by the present invention are enhanced, so that the oxynitride phosphors can be widely applied to LEDs or other optical electronic components.

Description

Method for synthesizing nitrogen oxide phosphor powder

The present invention relates to a method for synthesizing oxynitride phosphors, in particular to a method for synthesizing nitrogen oxides by first synthesizing bismuth silicate powder by chemical co-precipitation method and performing solid state reaction together with cerium nitride. The method of fluorescent powder.

Phosphorus materials are often used in cathode ray tubes, fluorescent tubes, light-emitting diodes (LEDs) and related display products. To date, more than 30 types of materials have been developed, such as alumina acid. a salt, a citrate, a nitride, an oxynitride, a molybdate or a tungstate, wherein the phosphor material made of a nitride or an oxynitride is a high-efficiency phosphor powder. Its crystal structure is relatively rigid, so it has better thermal stability and chemical stability, so it is very suitable for use with ultraviolet or blue LED chips to form a white LED to meet the high color rendering and stability required to produce white light. Basic requirements such as sex.

However, in order to synthesize a phosphor of such a nitride or an oxynitride, a synthesis condition of high temperature and high pressure is usually required. For example, LED plants generally use solid state reaction (SSR) as the main method of phosphor powder synthesis, which provides sufficient activation energy at high temperatures to facilitate the reaction of the powder. The solid state reaction method generally involves the following steps: (1) a diffusion reaction of a solid interface (such as an atom or ion across an interface); (2) an atomic scale chemical reaction; (3) a new phase nucleation; and (4) ), the movement of solids and the growth of new phases. Two important factors determining solid phase reactivity are nucleation and diffusion rates. Nucleation is easier to carry out if there is structural similarity between the product and the reactants. Diffusion phenomenon refers to the phenomenon that atoms move from a high concentration to a low concentration region in a solid, which can evenly distribute atoms in a solid. Generally, defects, interface morphology, atomic or ion size, etc. within the solid phase powder are related to the degree of diffusion.

The existing solid state reaction method for preparing the phosphor powder is to take a proper amount of the reactants according to a certain stoichiometry, thoroughly mix and then put into the crucible, and then put into a high temperature furnace and in a suitable reaction atmosphere. After heating and soaking for several hours, the mixture is cooled to room temperature, taken out, and finally pulverized and sieved to obtain the desired sample. The material obtained by this method has the advantages of stable powder performance and high brightness, and is favorable for industrial production; however, the disadvantage is that the powder needs to be calcined at a high temperature in a high temperature furnace of 1400 to 1600 ° C, and the higher the calcination temperature, the easier the particles are. Aggregation occurs, so the particle size of the product is large and the particle size distribution is too wide, and it is difficult to obtain a relatively uniform particle size, and it does not meet the energy saving industry trend. Furthermore, although ball milling can be used to further reduce the particle size, the powder and the grinding ball are subjected to rolling and rubbing during the grinding process, which tends to cause crystal defects in the powder crystal grains. Reduce its luminous efficiency. After ball milling and sieving, if smaller particles (such as nano-scale) are used, the surface area is larger, which usually causes surface defects to increase, thus reducing the luminous efficiency; if larger particles are used, it is not conducive to smoothing. It is applied to the LED wafer, and the larger particles will have a problem between the shielded partial beams, thereby reducing the light extraction efficiency.

Therefore, it is necessary to provide a method for synthesizing oxynitride phosphors to solve the problems of conventional techniques.

The main object of the present invention is to provide a method for synthesizing oxynitride phosphor powder, which first synthesizes citrate phosphor powder by chemical co-precipitation method, and then performs solid state reaction with cerium nitride for reaction synthesis. NOx phosphor powder, the crystallinity of the oxynitride phosphor is superior to that of the existing solid-state or secondary solid-state phosphor powder, and has higher quantum efficiency and thermal stability, and particle size Size and uniformity are also preferred, so that it can be better applied to photovoltaic elements such as light-emitting diodes.

To achieve the above object, the present invention provides a method for synthesizing oxynitride phosphors comprising the steps of: nitrate of a matrix metal M, at least one oxide of a doped metal Ln, and tetraethoxy decane (TEOS) Performing a chemical co-precipitation method to synthesize a bismuth silicate phosphor M _2-x SiO ₄ :xLn, wherein the matrix metal M is selected from lithium (Li), calcium (Ca), strontium (Sr) or strontium (Ba) The doping metal Ln is selected from any rare earth element, manganese (Mn), chromium (Cr) or strontium (Sb), 0.01<x<0.09, and the first reductive sintering is carried out by the co-precipitation method. Between 1200 and 1400; and solid state reaction of the bismuth silicate phosphor M _2-x SiO ₄ :xLn with lanthanum nitride (Si ₃ N ₄ ) to synthesize oxynitride phosphor M _{1 -x} Si ₂ O ₂ N ₂ :xLn, wherein 0.005 < x < 0.045, and the solid state method performs a second reductive sintering at a temperature between 1300 and 1500.

In an embodiment of the present invention, the step of the chemical co-precipitation method comprises: formulating a mixed aqueous solution of the nitrate of the matrix metal M, the oxide of the doped metal Ln, and tetraethoxy decane, and mixing the mixture. The aqueous solution is added to a precipitant of ammonium hydrogencarbonate (NH ₄ HCO ₃ ) to obtain a precipitate, which is filtered and dried, and the precipitate is subjected to a reducing atmosphere (5% H ₂ /95% N ₂ ). This first reduction sintering is carried out to obtain the phthalate phosphor M2 _-x SiO ₄ :xLn.

In one embodiment of the invention, the first reduction sintering time is between 4 and 8 hours.

In an embodiment of the present invention, the step of the solid state reaction method comprises: first mixing the phthalate phosphor powder M _2-x SiO ₄ :xLn with tantalum nitride (Si ₃ N ₄ ), followed by reduction This second reduction sintering was carried out under an atmosphere (5% H ₂ /95% N ₂ ) to obtain the oxynitride phosphor M _1-x Si ₂ O ₂ N ₂ :xLn.

In one embodiment of the invention, the second reduction sintering time is between 4 and 8 hours.

In an embodiment of the present invention, the matrix metal M is preferably selected from the group consisting of strontium (Sr), and the dopant metal Ln is preferably selected from the group consisting of lanthanum (Eu) in a rare earth element, and the oxynitride fluorescene powder M _{1 -x} Si ₂ O ₂ N ₂ : xLn is Sr _1-x Si ₂ O ₂ N ₂ : xEu.

In an embodiment of the invention, the matrix metal M is also selected from the group consisting of strontium (Sr), the dopant metal Ln is selected from the group consisting of cerium (Ce) in the rare earth element, and the oxynitride fluorescing powder M _1-x Si ₂ O ₂ N ₂ :xLn is Sr _1-x Si ₂ O ₂ N ₂ :xCe.

In an embodiment of the present invention, the matrix metal M is also selected from the group consisting of strontium (Sr), and the dopant metal Ln is simultaneously selected from the group consisting of lanthanum (Eu) and cerium (Ce) in the rare earth element, and the oxynitride The light powder M _1-x Si ₂ O ₂ N ₂ :xLn is Sr _1-x Si ₂ O ₂ N ₂ :yEu,zCe, where y+z=x.

In an embodiment of the invention, the oxynitride phosphor M _1-x Si ₂ O ₂ N ₂ :xLn is a green phosphor.

In an embodiment of the invention, the green phosphor is co-dispersed with a red phosphor in an encapsulant of a blue light emitting diode chip to form a white light emitting diode.

In one embodiment of the invention, the oxynitride phosphor M _1-x Si ₂ O ₂ N ₂ :xLn is dispersed in one of the solar conversion layers of a solar cell.

In one embodiment of the invention, the oxynitride phosphor M _1-x Si ₂ O ₂ N ₂ :xLn is interspersed in one of the encapsulants of a light-emitting diode plant growth lamp.

The above and other objects, features and advantages of the present invention will become more <RTIgt; Furthermore, the directional terminology referred to in the present invention, such as "upper", "lower", "inside", "outside" or "side", is merely a reference to the direction of the additional drawing. Therefore, the directional terminology used is for the purpose of illustration and understanding of the invention.

NOx phosphor powder materials have many advantages such as non-toxicity, chemical stability, good thermal stability, high energy efficiency, high luminous intensity, and variability in chemical composition and luminescence wavelength. However, it is necessary to synthesize such high-efficiency fluorescence. The synthesis conditions of the powder are relatively harsh, and the present invention focuses on the synthesis of the oxynitride phosphor.

The present invention will be hereinafter referred to as a control group in two ways of synthesizing oxynitride phosphors (solid state reaction method, two-stage solid state reaction method), in order to synthesize oxynitride fluoro powder with preferred embodiments of the present invention. Method for synthesizing the crystallinity of the synthesized phosphor powder of the present invention by first synthesizing the citrate fluorescein by chemical co-precipitation method and then performing the solid state reaction method together with cerium nitride It is superior to the phosphor powder synthesized by solid state reaction or two-stage solid state reaction, and has higher quantum efficiency and thermal stability.

(1) Solid-state reaction (SSR):

The existing solid-state reaction method mainly collects the original materials by stoichiometry, mixes them uniformly, and then puts them into a high-temperature tube furnace to calcine and synthesize the oxynitride phosphor powder.

For example, a solid-state reaction method for synthesizing cerium-doped cerium oxynitride (Sr _1-x Si ₂ O ₂ N ₂ :xEu) is exemplified by first weighing a raw material: strontium carbonate (SrCO ₃ ) by stoichiometry. , cerium oxide (SiO ₂ ), cerium nitride (Si ₃ N ₄ ) and cerium oxide (Eu ₂ O ₃ ), the weight ratio of which is shown in Table 1 below:

Next, the above starting materials are poured into a mortar and ground, uniformly mixed, and calcined at 1300 ° C for 6 hours under a reducing atmosphere (5% H ₂ /95% N ₂ ) to obtain the desired The ytterbium _- doped oxynitride powder (Sr _1-x Si ₂ O ₂ N ₂ :xEu, 0.01<x<0.09, for example, x=0.05), which is hereinafter referred to as SSR control fluoro powder .

(2) 2-step solid-state reaction (SSR2):

The existing two-stage solid state reaction method mainly performs the first solid state reaction calcination to obtain a niobate powder, and then the second solid state reaction calcination with the niobate powder and the tantalum nitride to obtain the nitrogen oxides. Light powder.

For example, a two-stage solid state reaction method for synthesizing cerium-doped cerium oxynitride (Sr _1-x Si ₂ O ₂ N ₂ :xEu) is exemplified by first weighing the starting material: strontium carbonate (SrCO) by stoichiometry ₃ ), cerium oxide (SiO ₂ ) and cerium oxide (Eu ₂ O ₃ ), the weight ratio of which is shown in Table 2 below:

Next, a first solid state reaction method is carried out, which is carried out by pouring the above-mentioned starting materials into a mortar, uniformly mixing them, and maintaining the temperature at 1300 ° C under a reducing atmosphere (5% H ₂ /95% N ₂ ). After 6 hours of calcination, the strontium strontium ruthenate (Sr _2-x SiO ₄ : xEu ²⁺ , 0.01<x<0.09) powder can be obtained first.

Then, a second solid state reaction method is carried out, which is prepared by using 0.5 mole of cerium-doped cerium lanthanum citrate powder and 0.5 mole of cerium nitride (Si ₃ N ₄ ) as a starting material. Pour into the mortar and grind it evenly, mix it uniformly, and carry out calcination at 1400 ° C for 6 hours under a reducing atmosphere (5% H ₂ /95% N ₂ ) to obtain cerium-doped cerium oxide powder. The body (Sr _1-x Si ₂ O ₂ N ₂ : xEu, 0.005 < x < 0.045, for example, x = 0.025), this powder is hereinafter referred to as SSR2 control phosphor powder.

(3) solid-state reaction followed by chemical co-precipitation reaction (SSRP):

The method for synthesizing oxynitride phosphor in the preferred embodiment of the present invention mainly comprises synthesizing bismuth fluorite powder by chemical co-precipitation method, and then performing solid state reaction together with cerium nitride to synthesize nitrogen oxides. Fluorescent powder.

For example, a method for synthesizing ytterbium _- doped lanthanum oxide (Sr _1-x Si ₂ O ₂ N ₂ :xEu) by using a method for synthesizing oxynitride phosphors according to a preferred embodiment of the present invention is exemplified by stoichiometry The preparation of the mother liquor containing ruthenium metal salt is as follows: firstly, tetraethoxy decane (TEOS, C ₈ H ₂₀ O ₄ Si) is used as a source of Si ions, and TEOS is mutually soluble with a small amount of alcohol and deionized water. Next, strontium nitrate (Sr(NO ₃ ) ₂ ) is dissolved in deionized water as a source of alkaline earth metal ions, and nitric acid (Eu ₂ O ₃ ) is added as a source of cerium ions to dissolve it, and its main component weight ratio As shown in Table 3 below:

Thereafter, the alkaline earth metal/cerium ion solution and the TEOS solution are mixed and stirred to obtain an alkaline earth metal salt solution (mother liquor), and the precipitating agent is prepared by dissolving ammonium hydrogencarbonate in deionized water and adjusting the pH to an appropriate pH with ammonia water. The alkaline earth metal salt solution (mother liquor) is slowly dropped into the precipitant to react the alkaline earth ions with the carbonate ions to form a precipitate. After the precipitate is dried, it is subjected to a reducing atmosphere (5% H ₂ /95% N ₂ ) at 1300 ° C. The calcination was carried out for 6 hours at a temperature to obtain a cerium-doped cerium lanthanum hydride (Sr _2-x SiO ₄ : xEu ²⁺ , 0.01 < x < 0.09) powder.

Then, the cerium-doped cerium lanthanum silicate powder synthesized by the above chemical co-precipitation method is subjected to a solid state reaction method together with cerium nitride, which is 0.5 mole-doped cerium lanthanum citrate powder and 0.5 mole Cerium nitride (Si ₃ N ₄ ) is used as a starting material, which is poured into a mortar and ground to homogenize and uniformly mixed under a reducing atmosphere (5% H ₂ /95% N ₂ ) at 1300 to 1500 ° C. Niobium _- doped oxynitride powder (Sr _1-x Si ₂ O ₂ N ₂ :xEu, 0.005<x<0.045, eg x=0.025) can be obtained by calcination at a temperature of 6 hours (for example, 1400 ° C). This powder is hereinafter referred to as the SSRP experimental group fluorescent powder of the present invention.

Results and discussion:

Referring to FIG. 1 , the photoluminescence (PL) characteristics of the SrSi ₂ O ₂ N ₂ :Eu ²⁺ phosphor powder synthesized by the SSR method, the SSR2 method and the SSRP method are disclosed. Comparative analysis chart (Y axis: PL intensity, arbitrary unit; X axis: wavelength, nano nm). It can be seen from Fig. 1 that the fluorescing powder of the SSRP experimental group of the present invention has the best luminescence intensity, followed by the SSR2 and SSR control phosphor powder, and the SSR2 control fluorophore has the luminescence intensity of the SSR control fluoro powder. The luminescence intensity of the SSRP experimental group of the present invention can be increased to 5.89 times of the luminescence intensity of the fluorescent powder of the SSR control group.

Please refer to FIG. 2, which discloses X-ray diffraction of Xr-ray diffraction of SrSi ₂ O ₂ N ₂ :Eu ²⁺ phosphor powder synthesized by the SSR method, the SSR2 method and the SSRP method in the present invention. Comparative analysis chart of XRD) (Y axis: intensity, arbitrary unit; X axis: 2θ, degree). It can be seen from Fig. 2 that the SSR control fluorescing powder has a diffraction peak of an unknown phase at 28.27°. In contrast, the SSR2 control fluoron powder can relatively reduce the diffraction peak intensity of the unknown phase, and relatively crystallization The improvement of the diffraction intensity of the SSRP experimental group of the present invention is better than that of the SSR and SSR2 control phosphor powders by comparing the diffraction peak intensity value with the half width and height. The crystallinity can relatively reduce the chance of non-radiative light emission at the defect, thereby improving the luminous intensity and thermal stability of the fluorescent powder.

Referring to FIG. 3, it is a scanning electron microscope (SEM) microscopy of SrSi ₂ O ₂ N ₂ :Eu ²⁺ phosphor powder synthesized by the SSR method, the SSR2 method and the SSRP method in the present invention. Photograph (3000 times). It can be seen from Fig. 3 that the crystal morphology of the phosphor powder of the SSRP experimental group of the present invention is relatively regular with respect to the SSR2 and SSR control phosphor powder, and the agglomeration phenomenon after high temperature calcination is less obvious. Generally, the phosphor powder of the spherical powder morphology can relatively reduce the scattering loss of incident light, and the agglomeration phenomenon is less obvious and the grain with relatively uniform particle size can reduce the scattering, and the powder can also obtain better stacking. Density, thus contributing to the increase in luminous intensity. Furthermore, the quantum efficiency of the SSRP experimental group phosphor powder was about 10.59% and 8.67% higher than that of the SSR and SSR2 control phosphors, respectively, under the excitation of a wavelength of 450 nm.

Referring to FIG. 4, it is shown that the thermal stability measurement of SrSi ₂ O ₂ N ₂ :Eu ²⁺ phosphor powder synthesized by the SSR method, the SSR2 method and the SSRP method is analyzed. (ie relative to the relative PL integral intensity versus temperature at room temperature). It can be seen from Fig. 4 that the relative PL integral intensity of each phosphor powder increases with the increase of temperature, and the relative PL integral intensity of the SSR control phosphor is 103% at 75 ° C. It continued to decrease as the temperature rose, and the relative PL integral intensity at 150 ° C was 92% at room temperature. Further, the relative PL integral intensity of the SSR2 control phosphor powder was 102% at 75 ° C, and then decreased with increasing temperature, and the relative PL integral intensity at 95 ° C was 95% at room temperature. Further, the relative PL integral intensity of the phosphor powder of the SSRP test group of the present invention was 105% at 50 ° C, and then decreased with an increase in temperature, and the relative PL integrated intensity at 102 ° C was 102% at room temperature.

It can be seen from the above thermal stability measurement results that the thermal quenching temperature (T50) of the phosphor powder is much higher than 150 ° C, and it is known that such a nitrogen oxide phosphor powder has good thermal stability. Among them, the thermal stability of the SSRP experimental group fluorescent powder and the SSR2 control fluorescent powder is better than that of the SSR control fluorescent powder, which is mainly due to the secondary phase content of the fluorescent powder synthesized by SSRP and SSR2. It is less, so the powder has higher crystallinity and the synthesized structure is more complete, so the thermal stability is better. For example, after half an hour of operation, the surface temperature of the crystal grain may exceed 100 ° C, or even approach 120 ° C, so the thermal stability of the phosphor powder will affect the overall luminous efficiency, color temperature and white light LED Color rendering.

Based on the results of the comparative analysis of the above Figures 1 to 4, it can be seen that the phosphor powder synthesized by the SSRP method (chemical co-precipitation method + solid state reaction method) of the present invention uses the SSR method (solid state reaction method) or the SSR2 method (the prior art). The two-stage solid state reaction method has better crystallinity, quantum efficiency, chemical stability, thermal stability and uniform powder particle size morphology, and can overcome the traditional synthesis conditions of high temperature and high pressure. The synthesis method of the invention can be extended to the synthesis of NOx phosphor powder, reduce the process cost of the NOx phosphor powder, and improve the illumination efficiency of the white LED, and achieve the vision of energy saving and carbon reduction.

In addition to the cerium-doped cerium oxide powder (Sr _1-x Si ₂ O ₂ N ₂ :xEu, 0.005<x<0.045) which is legally exemplified in the above preferred embodiment, the synthesis method of the present invention may also be extended. The oxynitride fluorescer is used for synthesizing other luminescent bands. For example, the synthesis method of the present invention can be extended to various oxynitride phosphors represented by M _1-x Si ₂ O ₂ N ₂ :xLn. At this time, the synthesis method of the present invention comprises the following two main steps: Step 1: chemical co-precipitation method using a nitrate of a matrix metal M, at least one oxide of a doped metal Ln, and tetraethoxy decane (TEOS). Synthesizing a phthalate phosphor M _2-x SiO ₄ :xLn, wherein the matrix metal M is selected from lithium (Li), calcium (Ca), strontium (Sr) or barium (Ba), the doped metal Ln It is selected from any rare earth element, manganese (Mn), chromium (Cr) or bismuth (Sb), 0.01<x<0.09, and the first reductive sintering by the co-precipitation method, the temperature is between 1200 and 1400 And step 2: solid-state reaction of the phthalate phosphor M _2-x SiO ₄ :xLn with lanthanum nitride (Si ₃ N ₄ ) to synthesize the oxynitride fluoron powder M _1-x Si ₂ O ₂ N ₂ :xLn, its 0.005 < x < 0.045, and the second reduction sintering of the solid state method, the temperature is between 1300 and 1500.

In more detail, in the step of the chemical co-precipitation method, the mixed solution of the nitrate of the matrix metal M, the oxide of the doped metal Ln and the tetraethoxy decane is formulated, and the mixed aqueous solution is added to the carbonated A precipitate is obtained by reacting a precipitant of ammonium hydrogen (NH ₄ HCO ₃ ), the precipitate is filtered off and dried, and the precipitate is subjected to a first reduction under a reducing atmosphere (5% H ₂ /95% N ₂ ). Sub-reduction sintering to obtain the phthalate phosphor M2 _-x SiO ₄ :xLn. The time for the first reduction sintering is between 4 and 8 hours.

Furthermore, the step of the solid state reaction method comprises: first mixing the phthalate phosphor powder M _2-x SiO ₄ :xLn with tantalum nitride (Si ₃ N ₄ ), followed by a reducing atmosphere (5% H) ₂ /95% N ₂ ) The second reduction sintering was carried out to obtain the oxynitride phosphor M _1-x Si ₂ O ₂ N ₂ :xLn. The second reduction sintering time is between 4 and 8 hours.

For example, in the above preferred embodiment of the present invention, the matrix metal M is strontium (Sr), and the doping metal Ln is lanthanum (Eu) in the rare earth element. At this time, the oxynitride fluorescene powder M _{1 -x} Si ₂ O ₂ N ₂ :xLn is Sr _1-x Si ₂ O ₂ N ₂ :xEu, and the oxynitride phosphor is a green phosphor (wavelength range 300-500 nm).

Furthermore, in another embodiment of the present invention, the matrix metal M may be selected from the group consisting of strontium (Sr), and the dopant metal Ln may be selected from the group consisting of cerium (Ce) in a rare earth element, in which case the oxynitride is fluorescent. The powder M _1-x Si ₂ O ₂ N ₂ :xLn is Sr _1-x Si ₂ O ₂ N ₂ :xCe, and the oxynitride phosphor is a green phosphor.

In addition, in another embodiment of the present invention, the matrix metal M may be selected from the group consisting of strontium (Sr), which may be simultaneously selected from the group consisting of lanthanum (Eu) and cerium (Ce) in the rare earth element, and the nitrogen Oxide phosphor powder M _1-x Si ₂ O ₂ N ₂ :xLn is Sr _1-x Si ₂ O ₂ N ₂ :yEu, zCe, the oxynitride phosphor is green phosphor powder, wherein y+z =x.

When a suitable oxynitride phosphor is synthesized according to the synthesis method of the present invention as needed, the oxynitride phosphor can be selected for use in various types such as white light emitting diodes (LEDs), solar cells, or plant growth lamps. In optoelectronic component products. For example, a green phosphor (such as Sr _1-x Si ₂ O ₂ N ₂ :xEu) can be synthesized according to the synthesis method of the present invention and co-dispersed with a red phosphor in an encapsulant of a blue LED chip. To form a white LED together. When the blue LED chip emits blue light (450 nm), a part of the blue light is incident on the green or red phosphor, and thus the green or red phosphor is excited to generate green or red light, and finally green light and red light. When the remaining blue light is emitted from the encapsulant, white light can be mixed and the luminous efficiency is 40 Lm/W, the color temperature is 4624K, CIE=(0.35, 0.35), and the color rendering property is 86.

Furthermore, in another embodiment of the present invention, the oxynitride fluoropolymer M _1-x Si ₂ O ₂ N ₂ :xLn may also be dispersed in a solar conversion layer of a solar cell, the sunlight conversion layer It may be located between one of the bottom surfaces of the solar cell and a silver reflective layer. At the same time, the oxynitride fluoron powder is preferably pre-designed to be converted to convert sunlight into a band gap wavelength that is closer to the wavelength of the absorption layer, so that the solar cell has better photoelectric conversion. effectiveness.

In addition, in another embodiment of the present invention, the oxynitride fluoropolymer M _1-x Si ₂ O ₂ N ₂ :xLn may also be dispersed in an encapsulant of an LED plant growth lamp. At the same time, the oxynitride phosphor is preferably pre-designed to excite broad blue-green light (wavelength 400-500 nm) and red light (wavelength 600-700 nm) so that the LED plant growth lamp can provide benefits to the plant. A light source for photosynthesis to maintain the growth quality of plants. The invention can also adjust the design and synthesis of oxynitride phosphors which can generate specific wavelengths according to the different light requirements of different plants.

The present invention has been disclosed in its preferred embodiments, and is not intended to limit the invention, and the present invention may be modified and modified without departing from the spirit and scope of the invention. The scope of protection is subject to the definition of the scope of the patent application.

Fig. 1 is a comparative analysis diagram showing the optical excitation spectrum (PL) characteristics of SrSi ₂ O ₂ N ₂ :Eu ²⁺ phosphor powder synthesized by the SSR method, the SSR2 method and the SSRP method.

Fig. ₂ is a comparative analysis diagram of X-ray diffraction (XRD) of SrSi ₂ O ₂ N ₂ :Eu ²⁺ phosphor powder synthesized by the SSR method, the SSR2 method and the SSRP method.

Fig. 3 is a (3000-fold) photomicrograph of a scanning electron microscope (SEM) of SrSi ₂ O ₂ N ₂ :Eu ²⁺ phosphor powder synthesized by the SSR method, the SSR2 method and the SSRP method.

Fig. 4 is a graph showing the comparison of the thermal stability of SrSi ₂ O ₂ N ₂ :Eu ²⁺ phosphor powder synthesized by the SSR method, the SSR2 method and the SSRP method.

Claims (12)

A method for synthesizing oxynitride phosphor powder, comprising the steps of: synthesizing a citrate by chemical coprecipitation with a nitrate of a matrix metal M, at least one oxide of a doped metal Ln, and tetraethoxy decane a phosphor powder M _2-x SiO ₄ :xLn, wherein the matrix metal M is selected from lithium (Li), calcium (Ca), strontium (Sr) or barium (Ba), and the doping metal Ln is selected from any rare earth element , manganese (Mn), chromium (Cr) or bismuth (Sb), 0.01 < x < 0.09, and the co-precipitation method performs the first reduction sintering, the temperature is between 1200 and 1400; Salt fluorescing powder M _2-x SiO ₄ :xLn and yttrium nitride (Si ₃ N ₄ ) are subjected to solid state reaction to synthesize oxynitride fluoron powder M _1-x Si ₂ O ₂ N ₂ :xLn, wherein 0.005 < x < 0.045, and the solid state method performs a second reductive sintering at a temperature between 1300 and 1500. The method for synthesizing oxynitride phosphors according to claim 1, wherein the step of the chemical co-precipitation method comprises: formulating the nitrate of the matrix metal M, the oxide of the doped metal Ln, and the fourth a mixed aqueous solution of ethoxy decane, and the mixed aqueous solution is added to a precipitant of ammonium hydrogencarbonate (NH ₄ HCO ₃ ) to obtain a precipitate, which is filtered and dried, and the precipitate is subjected to a reducing atmosphere. This first reductive sintering was carried out to obtain the phthalate phosphor M2 _-x SiO ₄ :xLn. The method of synthesizing oxynitride phosphors according to claim 1 or 2, wherein the first reduction sintering time is between 4 and 8 hours. The method for synthesizing oxynitride phosphors according to claim 1, wherein the step of the solid reaction method comprises: first mixing the phthalate phosphor M _2-x SiO ₄ : xLn with nitrogen The ruthenium oxide (Si ₃ N ₄ ) is then subjected to the second reduction sintering under a reducing atmosphere to obtain the oxynitride phosphor M _1-x Si ₂ O ₂ N ₂ :xLn. The method of synthesizing oxynitride phosphors according to claim 1 or 4, wherein the second reduction sintering time is between 4 and 8 hours. The method for synthesizing an oxynitride phosphor according to claim 1, wherein the matrix metal M is selected from the group consisting of strontium (Sr), and the dopant metal Ln is selected from the group consisting of lanthanum (Eu) in a rare earth element, and The oxynitride phosphor M _1-x Si ₂ O ₂ N ₂ :xLn is Sr _1-x Si ₂ O ₂ N ₂ :xEu. The method for synthesizing an oxynitride phosphor according to claim 1, wherein the matrix metal M is selected from the group consisting of strontium (Sr), and the dopant metal Ln is selected from the group consisting of cerium (Ce) in a rare earth element, and The oxynitride phosphor M _1-x Si ₂ O ₂ N ₂ :xLn is Sr _1-x Si ₂ O ₂ N ₂ :xCe. The method for synthesizing oxynitride phosphors according to claim 1, wherein the matrix metal M is selected from the group consisting of strontium (Sr) selected from the group consisting of lanthanum (Eu) and lanthanum (in the rare earth element) Ce), and the oxynitride phosphor M _1-x Si ₂ O ₂ N ₂ :xLn is Sr _1-x Si ₂ O ₂ N ₂ :yEu,zCe, where y+z=x. The method for synthesizing oxynitride phosphors according to claim 1, wherein the oxynitride fluorescing powder M _1-x Si ₂ O ₂ N ₂ :xLn is green fluorescent powder. The method for synthesizing oxynitride phosphors according to claim 9, wherein the green phosphor and a red phosphor are co-dispersed in a package colloid of a blue light emitting diode chip to form A white light emitting diode. The method for synthesizing oxynitride phosphors according to claim 1, wherein the oxynitride phosphor M _1-x Si ₂ O ₂ N ₂ :xLn is dispersed in a solar conversion layer of a solar cell. in. The method for synthesizing oxynitride phosphors according to claim 1, wherein the oxynitride phosphor M _1-x Si ₂ O ₂ N ₂ :xLn is dispersed in a light-emitting diode plant growth lamp One of the encapsulants.