TW201912765A - Preparation method of manganese-activated zinc aluminum spinel oxynitride phosphor powder capable of preparing a single-phase phosphor powder having high luminescent stability, high light-emitting strength, high thermal stability, and a single-phase phosphor powder having a single green light emission wavelength - Google Patents

Abstract

Disclosed is a preparation method of manganese-activated zinc aluminum spinel (ZnAl2O4:Mn2) oxynitride phosphor powder, including the following steps: (1) preparing a precursor solution, which comprises an initial solution and a manganese-containing activator, wherein the initial solution comprises a zinc salt, aluminium alkoxide and a solvent; (2) adding urea into the precursor solution and performing a hydrolysis reaction, so that a transparent sol is obtained; (3) subjecting the transparent sol to a polycondensation reaction in order to obtain a transparent gel; and (4) drying the transparent gel, then annealing under nitrogen or gas containing nitrogen, so as to obtain the ZnAl2O4:Mn2 oxynitride phosphor powder. The preparation method of the present invention is able to prepare a single-phase phosphor powder having high luminescent stability, high light-emitting strength, high thermal stability, and a single-phase phosphor powder having a single green light emission wavelength.

Description

Method for preparing manganese activated zinc aluminum spinel oxynitride fluorescent powder

The invention relates to a method for preparing a zinc-aluminum spinel oxynitride phosphor powder, in particular to a method for preparing a manganese-activated zinc-aluminum spinel oxynitride phosphor powder.

At present, the concept of environmental protection and energy conservation has been highly valued by the international community. How to develop green lighting products with high efficiency, high efficiency and low pollution has become an important trend. White light emitting diode (WLED) has the advantages of low power consumption, small size, long life, no mercury, no heat radiation and good reaction speed. It has gradually replaced traditional light bulbs as the mainstream of lighting equipment development.

WLED production technology can be divided into three types: (1) coating yellow phosphor powder on a blue light wafer, and (2) coating three primary color phosphor powder on an ultraviolet (UV) or near-ultraviolet (n-UV) wafer. The body, and (3) are mixed with a multi-wafer type LED to form white light. Since the application of the yellow phosphor powder on the blue light wafer has the advantages of easy fabrication, simple driving, good luminous intensity, and low cost, it has become a major development technology. The commercially available WLED is a cerium-doped yttrium aluminum garnet (Y ₃ Al ₅ O1 ₂ :Ce) phosphor powder coated with cadmium (Ce) on a GaN blue light emitting diode (LED). The utility model utilizes the blue light generated by the LED to excite the yttrium-doped yttrium aluminum garnet phosphor powder, so that the phosphor powder generates yellow light, and then the blue light and the yellow fluorescent light are complementarily mixed to generate white light. However, the commercial WLED described above has the disadvantage of low color rendering, and although it can be applied to street lamps and liquid crystal panel backlights, it is not suitable for indoor lighting. Therefore, there is still an urgent need to develop a phosphor powder that can generate green light by blue light to enhance the brightness of the WLED and improve color rendering.

Fluorescent powders which can generate green light by blue light excitation, such as " Ceramics International , vol. 39 (2013), p3691-3697", disclose the preparation of manganese-activated zinc-aluminum spinel (ZnAl by sol-gel method). ₂ O ₄ : Mn) green fluorescent powder, but since the composition of the aforementioned fluorescent powder is an oxide having low thermal stability, when the working temperature is raised (for example, exceeding 50 ° C), it is easy to cause The heat hardenability causes a decrease in luminous intensity.

Nitrogen oxides have stronger covalent bonds than oxides. If manganese-activated zinc-aluminum spinel oxynitride fluorescein is used to replace existing components, manganese-activated zinc-aluminum spinel oxide When the powder is light, the thermal stability of the phosphor powder can be improved. However, the current oxynitride-based phosphor powders are prepared by a solid state reaction method using high temperature and high pressure, which may cause disadvantages of powder coarsening, high energy consumption, and high cost processes, and thus it is known that solid state There are still a number of disadvantages in the reaction process for the preparation of manganese-activated zinc-aluminum spinel oxynitride phosphors.

Therefore, how to find a single-phase manganese-activated zinc-aluminum spinel NOx oxide with high luminescence stability, high luminescence intensity, high thermal stability, and single green light emission wavelength can be replaced by the existing solid state reaction method. The preparation method of the light powder has become the goal of current research.

Accordingly, it is an object of the present invention to provide a process for the preparation of a manganese activated zinc aluminum spinel oxynitride phosphor. The preparation method is to improve the existing sol-gel method and to prepare single-phase manganese-activated zinc-aluminum spinel oxynitride with high luminescence stability, high luminescence intensity, high thermal stability, and single green emission wavelength. Fluorescent powder.

Therefore, the method for preparing the manganese-activated zinc-aluminum spinel oxynitride phosphor powder of the present invention comprises the following steps: (1) preparing a precursor liquid, the precursor liquid comprising a starting solution and a manganese-containing activator, the starting solution Containing zinc salt, aluminum alkoxide and solvent; (2) adding urea to the precursor liquid and performing hydrolysis reaction to obtain a transparent sol, wherein the molar ratio of urea to zinc salt ranges from 0.5 to 10; The transparent sol is subjected to a polycondensation reaction to obtain a transparent gel; and (4) the transparent gel is dried, and then annealed under nitrogen or a gas containing nitrogen to obtain the manganese-activated zinc-aluminum spinel Nitrogen oxide phosphor powder.

The invention has the advantages that: since the preparation method of the invention needs to add urea in the hydrolysis process and needs to be annealed under nitrogen or a gas containing nitrogen, it can prepare high luminescence stability, high luminescence intensity and high thermal stability. And a single phase manganese activated zinc aluminum spinel oxynitride phosphor powder having a single green light emission wavelength.

It should be specially stated that the addition of urea during the hydrolysis process can promote the uniform hydrolysis, and the urea and the nitrogen or the nitrogen-containing gas can be used as a nitrogen source to increase the manganese-activated zinc-aluminum spinel finally produced. The nitrogen content of the oxynitride phosphor powder, therefore, the present invention enables the preparation of single-phase manganese activation with high luminescence stability, high luminescence intensity, high thermal stability, and single green emission wavelength by sol-gel method. Zinc-aluminum spinel oxynitride phosphor powder.

The contents of the present invention will be described in detail below:

[ step (1)]

Preferably, the manganese-containing activator is a manganese salt. More preferably, the manganese-containing activator is selected from the group consisting of manganese nitrate, manganese chloride or a combination of the foregoing.

Preferably, the zinc salt is zinc nitrate, zinc chloride or a combination of the foregoing.

Preferably, the aluminum alkoxide is aluminum isopropoxide.

Preferably, the solvent is an alcohol. More preferably, the alcohol solvent has a concentration of 10 to 20 moles per liter. More preferably, the solvent is methanol, ethanol or a combination of the foregoing.

Preferably, the molar ratio of the aluminum alkoxide to the zinc salt ranges from 1.5 to 2.5. More preferably, the molar ratio of the aluminum alkoxide to the zinc salt is 2.

Preferably, the molar ratio of the manganese-containing activator to the zinc salt ranges from 0.005 to 0.1. More preferably, the molar ratio of the manganese-containing activator to the zinc salt ranges from 0.005 to 0.05.

Preferably, in the step (1), the zinc salt, the aluminum alkoxide and the solvent are first mixed and reacted with stirring to form a starting solution, and then a manganese-containing activator is added to form a precursor liquid in the starting solution. More preferably, the step (1) is to stir the reaction at 25 to 35 °C. More preferably, the step (1) is a stirring reaction for 1 to 2 hours.

[ step (2)]

It should be noted that when the molar ratio of urea to zinc salt is greater than 10, the obtained manganese-activated zinc-aluminum spinel oxynitride fluorochrome will produce a second phase of Al ₂ O ₃ (ie, not a single phase). ), and the added urea also affects the homogeneity of the transparent gel, resulting in a decrease in the luminescence intensity of the finally obtained manganese-activated zinc-aluminum spinel oxynitride phosphor powder.

Preferably, the molar ratio of urea to zinc salt ranges from 1 to 5. More preferably, the molar ratio of urea to zinc salt ranges from 1 to 3. When the ratio of the molar ratio of urea to zinc salt is in the range of 1 to 3, the obtained manganese-activated zinc-aluminum spinel oxynitride phosphine powder has a higher luminous intensity.

Preferably, the step (2) is carried out at 25 to 35 ° C for the hydrolysis reaction.

Preferably, the step (2) is carried out for a hydrolysis reaction for 1 to 2 hours.

[ step (3)]

Preferably, the step (3) is a polycondensation reaction at 25 to 35 °C.

Preferably, the step (3) is a polycondensation reaction at a relative humidity of 55 to 80%.

Preferably, the step (3) is carried out by a polycondensation reaction for 75 to 120 hours.

[ step (4)]

Preferably, the step (4) is drying at 80 to 200 °C.

Preferably, the step (4) is annealing at 300 to 1200 °C. More preferably, the step (4) is annealing at 1000 to 1200 °C. When the step (4) is annealed at 1000 to 1200 ° C, the obtained manganese-activated zinc-aluminum spinel oxynitride phosphor powder has a higher luminous intensity.

Preferably, the step (4) is annealing at 1000 to 1200 ° C under nitrogen.

Preferably, in the step (4), the nitrogen-containing gas is a nitrogen-hydrogen mixed gas. More preferably, the step (4) is performed after annealing at 1200 ° C under nitrogen and then at 1000 ° C under a mixture of nitrogen and hydrogen.

Preferably, the step (4) is annealing for 2 to 6 hours.

[ Manganese activated zinc-aluminum spinel oxynitride fluorescein ]

Preferably, the experimental formula of the manganese-activated zinc-aluminum spinel oxynitride is Zn _1-x Mn _x Al ₂ O _4-y N _y , wherein 0.005 ≦ x ≦ 0.10, 0.06 ≦ y ≦ 0.12.

Preferably, the manganese-activated zinc-aluminum spinel oxynitride phosphor has an illuminating intensity of 80% or more at an operating temperature of 200 °C.

Preferably, the manganese-activated zinc-aluminum spinel oxynitride phosphor has an excitation light wavelength of 455 nm and a radiation wavelength of 512 nm.

< Example 1~4>

Preparation of Manganese Activated Zinc Aluminate Spinel Nitrogen Oxide Phosphor Powder The manganese activated zinc aluminum spinel oxynitride phosphor powder of Examples 1 to 4 is a manganese nitrate (manganese activator) and urea according to Table 1. Addition amount (Mn/Zn and U/Zn), annealing temperature, annealing atmosphere environment, and the following steps: Step (1) : Take 0.2 mol of zinc nitrate, 0.4 mol of aluminum isopropoxide The reaction was stirred for 1 hour at a concentration of 10 mol/liter in a methanol solvent at 25 ° C to form a starting solution, and then manganese nitrate was added to the starting solution to form a precursor solution. Step (2) : After adding urea to the precursor liquid and performing a hydrolysis reaction at 25 ° C for 2 hours, a transparent sol was obtained. Step (3) : The transparent sol is subjected to a polycondensation reaction at 25 ° C and a relative humidity of 80% for 75 to 120 hours to obtain a transparent gel. Step (4) : The transparent gel is dried at 80 to 200 ° C and refined into a colloidal powder. Next, the colloidal powder is annealed for 2 hours, and then cooled to room temperature to obtain a manganese-activated zinc-aluminum spinel oxynitride phosphor powder (Experimental formula: Zn _1-x Mn _x Al ₂ O _4-y N _y , x=0.03, y=0.06~0.12). Table 1

< Example 5>

The preparation method of the manganese-activated zinc-aluminum spinel oxynitride fluorescer powder is shown in Table 1. The preparation method of the manganese-activated zinc-aluminum spinel oxynitride fluoresce powder of the embodiment 5 is similar to that of the embodiment 4, and the difference is that Example 5 was annealed at 1200 ° C for 2 hours under nitrogen, and then annealed at 1000 ° C under a nitrogen-hydrogen mixture (95% nitrogen and 5% hydrogen) for 2 hours, and Example 4 was under nitrogen. Different annealing is performed.

< Comparative example 1~19>

Preparation of Manganese Activated Zinc Aluminate Spinel Fluorescent Powder The preparation method of the manganese activated zinc aluminum spinel fluoresce powder of Comparative Examples 1 to 19 is similar to that of Example 1, except that Comparative Examples 1 to 19 are manganese nitrate according to Table 2. (Manganese-containing activator) was prepared by adding the amount of urea (Mn/Zn and U/Zn), annealing temperature, and annealing atmosphere. Table 2

<X- Light diffraction (X-ray diffraction, XRD) analysis >

Analytical method

The phosphor powders obtained in Example 3 and Comparative Example 1 were subjected to X-ray diffraction analysis, respectively, and the results are shown in the X-ray diffraction diagrams of Figs. 1 and 2, wherein Fig. 2 is the embodiment 3 and Comparative Example 1 is a diffraction peak of the (220) and (311) crystal faces.

Results and discussion

It can be found from Fig. 1 that neither the third embodiment in which urea is added to the hydrolysis process nor the first embodiment in which no urea is added has any Zn-N or Al-N second phase, indicating that the preparation method of the present invention can produce a single phase. Manganese activated zinc-aluminum spinel oxynitride phosphor powder.

Further, as can be seen from FIG. 2, the diffraction peak of Example 3 is shifted to a low angle and the full width at half maximum is increased as compared with the diffraction peaks of the (220) and (311) crystal faces of Comparative Example 1. Due to the increase in the solid solubility of nitrogen and the grain refinement, the N ^3– scorpion and O ^2– scorpion are displaced and dissolved in the ZnAl ₂ O ₄ lattice. The lattice strain occurs due to the difference in the radius of the raft. The diffraction peak is shifted to a low angle, and urea can promote uniform hydrolysis, so that the colloidal particles have a more uniform and fine distribution, and the crystallites have a smaller grain size and an increase in the full width at half maximum. Therefore, according to the foregoing description, it was confirmed that the phosphor powder obtained by adding urea to the hydrolysis process of the present invention is a nitrogen-containing compound (manganese-activated zinc-aluminum spinel oxynitride).

< Reversal rate δ (inversion rate, %) analysis >

Analytical method

The phosphor powders obtained in Example 3 and Comparative Examples 1 and 4 to 9 were each subjected to an inversion rate δ (%) analysis, which was an XRD full-spectrum fitting (scanning) using the Rietveld method. The range 2θ was 20 ^° ~ 140 ^° ), and the inversion rate δ (%) of Example 3 and Comparative Examples 1 and 4 which were finally calculated was summarized in Table 3 below, and the inversion rate δ of Comparative Examples 5 to 9 was obtained. (%) is shown in Figure 3. Among them, when the inversion rate δ (%) is higher, it means that the more easily Al ³⁺ in the zinc-aluminum spinel occupies the tetrahedral lattice position, the anti-spinel structure is formed, and the crystal structure of the zinc-aluminum spinel is less. Stable, and thus the luminescence stability of the zinc-aluminum spinel will decrease. table 3

Results and discussion

As can be seen from Table 3, in Comparative Example 1 in which urea was not added and Comparative Example 4 in which annealing was performed under air, the present invention had a lower reversal in Example 3 in which urea was added during the hydrolysis and annealed under nitrogen. The rate δ (%), that is, Example 3 has a high luminescence stability. Therefore, it can be seen from the foregoing that the manganese activated zinc obtained by the method for preparing urea in the hydrolysis process and the annealing method under nitrogen or under a nitrogen-containing gas is compared with the preparation method in which no urea is added or annealing is performed under air. The aluminum spinel oxynitride phosphor powder has high luminescence stability.

In addition, it can be found from Fig. 3 that the higher the molar ratio (Mn/Zn) of manganese nitrate (manganese activator) to zinc nitrate, the higher the inversion rate δ (%) of the obtained phosphor powder. high. It is particularly worth mentioning that when the ratio of the molar ratio of manganese nitrate (manganese activator) to zinc nitrate is not more than 0.05, it will have a lower inversion rate, that is, it will have higher luminous stability. It should be noted that the same conclusion should be obtained if the comparative examples 5 to 9 were replaced by annealing under nitrogen or under a gas containing nitrogen.

<X- Photoelectron spectrometer (X-ray photoelectron spectroscopy, XPS) analysis >

Analytical method

The phosphor powders of Examples 1 to 2, 4 and Comparative Examples 1 and 12 were separately analyzed by X-ray photoelectron spectrometer, and the chemical compositions and chemical formulas were respectively classified in Tables 4 and 5 below, and the N1s spectrum thereof was obtained. Then, as shown in FIG. 4 (Comparative Example 12), FIG. 5 (Comparative Example 1), FIG. 6 (Example 1), and FIG. 7 (Example 3). Table 4 table 5

Results and discussion

As can be seen from Table 4 and Table 5, the nitrogen content in the phosphor powder obtained in Comparative Example 12 which was annealed in air and Comparative Example 1 in which urea was not added was much lower than that of the phosphor powder obtained in Examples 1, 2 and 4. The nitrogen content, and Figures 4 to 7 again confirmed that the nitrogen content of the phosphor powder obtained in Comparative Example 12 and Comparative Example 1 was indeed much lower than the nitrogen content of the phosphor powder obtained in Example 1 and Example 2. Therefore, it can be seen from the foregoing that the preparation method of adding urea in the hydrolysis process and annealing under nitrogen or under a nitrogen-containing gas can be prepared compared with the preparation method in which no urea is added or annea is performed under air. The high nitrogen solid solubility manganese activated zinc aluminum spinel oxynitride phosphor powder, and the manganese activated zinc aluminum spinel oxynitride phosphor powder obtained by the invention has high thermal stability.

< Infrared light spectrum (infrared spectroscopy, IR) analysis >

Analytical method

The phosphor powders obtained in Comparative Examples 3, 12, and 14 to 17 were analyzed by an infrared light spectrometer, and the obtained IR spectrum was as shown in FIG. The annealing temperatures of Comparative Examples 3, 12, and 14 to 17 are as shown in Table 6. Table 6

Results and discussion

It can be found from Fig. 8 that when the annealing temperature is between 300 and 1200 °C, there are absorption peaks at wavenumbers of 665 cm ^-1 , 554 cm ^-1 and 496 cm ^-1 , which is the octahedral intercalation of AlO in the spinel structure. The characteristic absorption peak of the _6- functional group, and the characteristic absorption peaks are more obvious as the annealing temperature rises, indicating that the crystallinity of the zinc-aluminum spinel increases as the annealing temperature increases. It should be noted that the same conclusion should be obtained if the comparative examples 3, 12, and 14-17 are replaced by annealing under nitrogen or under a nitrogen-containing gas.

< Scanning electron microscope (Scanning Electron Microscope, SEM) analysis >

The phosphor powders of Comparative Examples 2 to 3, 10, and 12 were photographed by a scanning electron microscope, and the obtained SEM photographs were as shown in Fig. 9 (Comparative Example 2), Fig. 10 (Comparative Example 3), and Fig. 11 (Comparative Example 10). ) is shown in Fig. 12 (Comparative Example 12). The amount of urea added (U/Zn) and the annealing temperature of Comparative Examples 2 to 3, 10, and 12 were summarized in Table 7 below. Table 7

Results and discussion

Comparing Fig. 9 with Fig. 10 and comparing Figs. 11 and 12, it can be found that the phosphor powder obtained in Comparative Examples 2 and 10 in which no urea was added was partially agglomerated, and the flakes obtained in Comparative Examples 3 and 12 in which urea was added during the hydrolysis process were obtained. The phosgene will be in the form of particles and spheres. According to the foregoing comparison, the addition of urea in the hydrolysis process can significantly reduce the agglomerated state of the obtained phosphor powder, and obtain a phosphor powder having a fine particle size, a near spherical shape and a narrow particle size distribution. It should be noted that the same conclusion should be obtained if the comparative examples 2 to 3, 10, and 12 are replaced by annealing under nitrogen or under a nitrogen-containing gas.

< Electron paramagnetic resonance (electron paramagnetic resonance, EPR) analysis >

The phosphor powders obtained in Comparative Examples 18 to 19 were analyzed by an electron paramagnetic resonance spectrometer, and the obtained electron paramagnetic resonance spectra were as shown in Fig. 13 (Comparative Example 18) and Fig. 14 (Comparative Example 19), respectively.

Results and discussion

It can be seen from FIG. 13 and FIG. 14 that the g powder of the phosphor powder obtained in Comparative Example 18 in which no urea was added approached 2, but the six-fold fine structure could not be clearly distinguished because the Mn ²⁺ scorpion agglomerated or The dipole interaction occurs in pairs; the g powder of the phosphor powder obtained in Comparative Example 19 in which the urea is added in the hydrolysis process also approaches 2, but six of them are spin quantum 數m=±5/ 2. ±3/2, and ±2/1 hyperfine line. The foregoing results were caused by the distribution 狀 state of Mn ²⁺ scorpion in the main body, and the g value of Comparative Example 19 was nearly 2 and had six high-resolution superfine lines, indicating Mn in the phosphor powder obtained in Comparative Example 19. ^{The 2+ scorpion} is evenly distributed in the main body, indicating that the addition of urea during the hydrolysis process can promote the more uniform distribution of Mn ^{2+ scorpion} , and can increase the luminous efficiency of the luminescent powder. It is particularly worth mentioning that if the fluorescing powder is annealed at 1200 ° C under nitrogen and then annealed at 1000 ° C under a nitrogen-hydrogen mixture, the six ultrafine line intensities of the electron paramagnetic resonance spectrum. Will increase significantly, indicating that the distribution of Mn ^{2+ scorpion} will be more uniform, and thus the luminous efficiency is better. It should be noted that the same conclusion should be obtained if the comparative examples 18 to 19 were replaced by annealing under nitrogen or under a gas containing nitrogen.

< Luminous intensity analysis of fluorescent powder >

A. Analysis one:

Analytical method

The phosphors obtained in Examples 2, 4 to 5 and Comparative Examples 2 and 3 were each excited by excitation light having a wavelength of 455 nm, and the obtained emission spectrum is shown in Fig. 15 . The amount of urea added, the annealing temperature and the environment of Examples 2, 4 to 5 and Comparative Examples 2 and 3 were summarized in Table 8 below. Table 8

Results and discussion

It can be seen from Fig. 15 that after excitation with excitation light having a wavelength of 455 nm, a single radiation peak having a wavelength of 512 nm can be obtained in either of Examples 2, 4 to 5 or Comparative Examples 2 and 3, indicating the preparation method of the present invention. The manganese-activated zinc-aluminum spinel oxynitride phosphor powder does emit green light having a single wavelength.

It can be also seen from Fig. 15 that under the same annealing temperature and environment conditions, the relative intensity (i.e., luminescence intensity) of the phosphor powder obtained in Comparative Example 3 in which urea is added during the hydrolysis process is higher than that in Comparative Example 2 in which urea is not added. And the relative intensity (ie, luminescence intensity) of the phosphor powder obtained in Example 2 which was annealed under nitrogen under the conditions of the same urea addition amount and annealing temperature was higher than that of Comparative Example 3 which was annealed under air, indicating the phase Compared with the preparation method in which urea is not added or annealed under air, the manganese activated spinel oxynitride obtained by adding the urea in the hydrolysis process and the annealing method under nitrogen or under a nitrogen-containing gas is prepared. Fluorescent powders have a higher luminous intensity.

In addition, from the comparison between Example 2 and Example 4 in Fig. 15, it can be found that the annealing temperature has a higher luminous intensity at 1200 ° C, and the annealing is performed at 1200 ° C under nitrogen, and then at 1000 ° C and nitrogen. Example 5, which was annealed under a hydrogen gas mixture, had the highest luminescence intensity.

B. Analysis 2:

Analytical method

The phosphor powders obtained in Comparative Examples 11 to 13 were each excited by excitation light having a wavelength of 455 nm, and the obtained emission spectrum is shown in Fig. 16 . Among them, the urea addition amount, the annealing temperature, and the environment of Comparative Examples 11 to 13 were summarized in Table 9 below. Table 9

Results and discussion

It can be seen from Fig. 16 that the relative strength (i.e., luminescence intensity) of the phosphor powder increases as the urea addition amount (U/Zn) increases in Comparative Examples 11 and 12, but when the urea addition amount (U/Zn) increases In Comparative Example 13 of 10, the relative intensity (i.e., luminescence intensity) was again lower than Comparative Examples 11 and 12 in which the urea addition amount (U/Zn) was 1 and 3. The foregoing result is because the addition of urea can make the Mn ²⁺ ions more evenly distributed (see <Electronic Paramagnetic Resonance Analysis>). However, when the amount of urea added is too large, the homogeneity of the transparent gel is affected, which leads to the final result. The luminous intensity of the phosphor powder will decrease. It should be noted that the same conclusion should be obtained if the comparative examples 11 to 13 were changed to be annealed under nitrogen or under a gas containing nitrogen.

< Thermal stability analysis of fluorescent powder >

Analytical method

The relative intensity of the radiant peak of the wavelength of 512 nm (au; excited by excitation light with a wavelength of 455 nm) at different operating temperatures was measured for the phosphor powder obtained in Example 2 and Comparative Example 12, respectively. As shown in Figure 17.

Results and discussion

It can be seen from Fig. 17 that the phosphor powder obtained in Example 2 still has a relative intensity (i.e., luminescence intensity) of 80% or more at an operating temperature of 200 ° C, whereas Comparative Example 12 only has a relative strength of about 40% remaining (i.e., The luminescence intensity), that is, the decrease in the luminescence intensity of the luminescent powder obtained in Example 2, which is smaller than the luminescence intensity of the fluorescing powder obtained in Comparative Example 12, as the operating temperature is increased, and the luminescent powder obtained in Example 2 is described. The thermal stability of the phosphor powder obtained in Comparative Example 12 was higher than that of Comparative Example 12. Therefore, as can be seen from the foregoing description, the manganese-activated zinc-aluminum spinel oxynitride fluoresce obtained by the preparation method of the present invention which is annealed under nitrogen or under a nitrogen-containing gas is compared with the preparation method of annealing under air. The powder will have a high thermal stability. It should be particularly noted that the same conclusion can be obtained if the second embodiment is replaced with another embodiment.

In summary, the preparation method of the present invention requires urea to be added during the hydrolysis process and needs to be annealed under nitrogen or a gas containing nitrogen, thereby producing high luminescence stability, high luminescence intensity, high thermal stability, and The single-phase manganese-activated zinc-aluminum spinel oxynitride phosphor powder of a single green light emission wavelength can indeed achieve the object of the present invention.

However, the above is only the embodiment of the present invention, and the scope of the invention is not limited thereto, and all the simple equivalent changes and modifications according to the scope of the patent application and the patent specification of the present invention are still Within the scope of the invention patent.

Other features and effects of the present invention will be apparent from the following description of the drawings, wherein: Figure 1 is an X-ray diffraction pattern illustrating the X-ray diffraction pattern of Example 3 and Comparative Example 1. 2 is an X-ray diffraction diagram illustrating diffraction peaks of the crystal planes of (220) and (311) of Example 3 and Comparative Example 1; FIG. 3 is a line diagram illustrating that Comparative Examples 5 to 9 are different. Inversion rate (δ, %) in Mn/Zn; Figures 4 to 7 are respectively an N1s energy spectrum, which respectively show Comparative Example 12 (Fig. 4), Comparative Example 1 (Fig. 5), and Example 1 (Fig. 6) And the N1s spectrum of the embodiment 3 (Fig. 7); Fig. 8 is an infrared spectrum of the infrared light spectrum of Comparative Examples 3, 12, and 14 to 17; Figs. 9 to 12 are respectively SEM photographs, respectively The appearance of the phosphor powder of Comparative Example 2 (Fig. 9), Comparative Example 3 (Fig. 10), Comparative Example 10 (Fig. 11) and Comparative Example 12 (Fig. 12) will be described; Figs. 13 to 14 are an electron paramagnetic, respectively. The resonance spectrum maps respectively show the electron paramagnetic resonance spectrum patterns of Comparative Example 18 (Fig. 13) and Comparative Example 19 (Fig. 14); Fig. 15 is a graph showing Examples 2, 4 to 5 and Comparative Examples 2 and 3. The obtained phosphor powder is excited by excitation light having a wavelength of 455 nm, respectively. The relative intensity (au) of the radiation peak having a wavelength of 512 nm was measured; FIG. 16 is a graph showing that the phosphor powders obtained in Comparative Examples 11 to 13 were respectively excited by excitation light having a wavelength of 455 nm. The relative intensity (au) of the radiation peak at a wavelength of 512 nm; and FIG. 17 is a line diagram illustrating the radiation peaks of the phosphor powder obtained in Example 2 and Comparative Example 12 at a wavelength of 512 nm at different operating temperatures. Relative intensity (au; excited by excitation light with a wavelength of 455 nm).

Claims (10)

A method for preparing a manganese-activated zinc-aluminum spinel oxynitride phosphor powder comprises the following steps: (1) preparing a precursor liquid, the precursor liquid comprising a starting solution and a manganese-containing activator, the starting solution containing a zinc salt (a) adding urea to the precursor liquid and performing a hydrolysis reaction to obtain a transparent sol, wherein the molar ratio of the urea to the zinc salt ranges from 0.5 to 10; (3) making the transparent The sol is subjected to a polycondensation reaction to obtain a transparent gel; and (4) the transparent gel is dried, and then annealed under nitrogen or a gas containing nitrogen to obtain the manganese-activated zinc-aluminum spinel oxynitride. Fluorescent powder. The method for preparing a manganese-activated zinc-aluminum spinel oxynitride phosphor powder according to claim 1, wherein the molar ratio of the manganese-containing activator to the zinc salt ranges from 0.005 to 0.1. The method for preparing a manganese-activated zinc-aluminum spinel oxynitride phosphor powder according to claim 1, wherein the molar ratio of the urea to the zinc salt ranges from 1 to 5. The method for preparing a manganese-activated zinc-aluminum spinel oxynitride phosphor powder according to claim 1, wherein the step (4) is annealing at 300 to 1200 °C. The method for preparing a manganese-activated zinc-aluminum spinel oxynitride phosphor powder according to claim 1, wherein the step (4) is annealing at 1000 to 1200 ° C under nitrogen. The method for producing a manganese-activated zinc-aluminum spinel oxynitride phosphor powder according to claim 1, wherein in the step (4), the nitrogen-containing gas is a nitrogen-hydrogen mixed gas. The method for preparing a manganese-activated zinc-aluminum spinel oxynitride phosphor powder according to claim 6, wherein the step (4) is performed at 1200 ° C under nitrogen and then at 1000 ° C and nitrogen hydrogen. Annealing is carried out under a mixed gas. The method for preparing a manganese-activated zinc-aluminum spinel oxynitride phosphine powder according to claim 1, wherein the manganese-activated zinc-aluminum spinel oxynitride has an experimental formula of Zn _1-x Mn _x Al ₂ O _4-y N _y , where 0.005≦x≦0.10, 0.06≦y≦0.12. The method for preparing a manganese-activated zinc-aluminum spinel oxynitride phosphor powder according to claim 1, wherein the manganese-activated zinc-aluminum spinel oxynitride phosphor powder has an operating temperature of 200 ° C. It has a luminous intensity of 80% or more. The method for preparing a manganese-activated zinc-aluminum spinel oxynitride phosphor powder according to claim 1, wherein the manganese-activated zinc-aluminum spinel oxynitride phosphor powder has an excitation light wavelength of 455 nm. The emitted light has a wavelength of 512 nm.