CN104610967A - A kind of rare earth doped nitrogen oxide green fluorescent powder and preparation method thereof - Google Patents

Abstract

The invention relates to rare earth doped nitrogen oxide green fluorescent powder and a preparation method thereof. Has a chemical formula of Ba_1-yLn_xAl_2-x-zSi_zO_4-zN_z:yEu²⁺(Ln = Y, La, Gd, Lu). The preparation method comprises the following steps: taking simple substances, oxides or corresponding salts of Si, Al, Ba and Ln (Ln = Eu, Y, La, Gd and Lu) as raw materials, weighing according to the stoichiometric ratio of a chemical formula, and adding a fluxing agent; after fully grinding, placing the mixture in a sintering furnace, roasting at a high temperature for the first time, reducing and sintering for the second time, and performing post-treatment to obtain the final product, namely the nitrogen oxide green fluorescent powder. According to the invention, through doping of rare earth ions and addition of a fluxing agent, the preparation conditions and the luminous effect are improved, the manufacturing is simple, no pollution is caused, and the cost is low; the ultraviolet light to blue light region has stronger excitation peak, and under the excitation of ultraviolet light and blue light, the light-emitting diode can emit bright green light, and has potential application value in the aspects of illumination and display.

Description

A kind of rare earth doped nitrogen oxide green fluorescent powder and preparation method thereof

technical field

The invention belongs to the technical field of fluorescent powder for excitation from ultraviolet light to blue light, and discloses a rare earth-doped nitrogen oxide green fluorescent powder material and a preparation method thereof.

Background technique

Today, white LEDs are mainly realized through "blue LEDs + yellow (red, green) phosphors" and "ultraviolet LEDs + red, green, and blue phosphors". The currently used phosphors have many problems in color rendering index, color temperature, color gamut index and anti-deterioration ability. Therefore, in today’s market where the color temperature and color rendering of LED light-emitting devices are increasingly demanding, it is necessary to find a physical Stable chemical properties, high luminous efficiency, and high-quality green nitrogen oxide phosphors with excellent performance are particularly important.

The nitrogen oxide green light phosphors that have been reported mainly include: first in 1996 by Karunaratne [Karunaratne B, Lumby R, Lewis M. J. Mater. Sci. Lett. 1996, 12 (2): 53-56.] and Shen Zhijian [Shen Zhijian Z, Nygren M, Halenius U. J. Mater. Sci. Lett. 1997, 16(4): 263-266.] reported the optical properties of rare earth ion doped SiAlON, which opened the door to the study of SiAlON as a functional material. In 2005, the Japanese research group Hirosaki[Hirosaki N, Xie R J, Kimoto K et al. Appl. Phys． Lett． 2005, 86: 211905.] Prepared β-SiAlON:Eu ²⁺ green phosphor through high-temperature solid-state reaction process (1900°C for 8h). A green narrow-band emission with a half-maximum width of about 55 nm is produced. In 2005, Holland University of Science and Technology [Li Y Q, Delsing A C A, With G de et al. Chem. Mater． , 2005, 17:3242. ] MSi ₂ O _2－δ N _2+2/3δ :Eu ²⁺ (M = Ca, Sr, Ba) phosphors were prepared by high-temperature solid-state reaction method. These phosphors can be effectively excited by 370-460nm light. In 2006, the National Institute of Materials Science of Japan first applied β-sialon:Eu ²⁺ green phosphor to LEDs, and jointly applied for the Chinese patent CN200610058559.5 with Fujikura Co., Ltd. In 2007, Sharp Corporation filed the application number A new preparation method is proposed in CN200710186804.5. When the outer layer of the compound of the active element is coated with a compound containing Si and Al with a lower melting point, a small specific surface, low impurity content and high luminous intensity can be obtained. product of. In 2008, Xie et al [Xie R J, Hirosaki N, Liu X J et al. Appl. Phys． Lett． 2008, 92:201905.] Mn ²⁺ —Mg ²⁺ co-doped γ—AlON-based green phosphors were prepared by a high-temperature solid-state reaction process. Make Mn ²⁺ replace the position of Al ³⁺ tetrahedron center. There are 5 excitation peaks at 340, 358, 381, 424 and 445nm in the excitation spectrum of the phosphor, and green light emission occurs at 520nm. In 2009, Bai Zhaohui et al. conducted research on Sr-Al-ON series phosphors for white light LEDs, and published the invention patent application number 200910067328.4. In 2011, Song et al. of Sungkyunkwan University (Sungkyunkwan University) [Song Y H, Choi T Y, Luo Y Y et al. Opt. Mater． 2011, 33: 989． ] prepared CaSi ₆ N ₈ O:Eu ²⁺ and Ba ₃ Si ₆ O ₁₂ N ₂ :Eu ²⁺ phosphors. Under 465nm light excitation, Ba ₃ Si ₆ O ₁₂ N ₂ :Eu ²⁺ emits green light with an emission peak at 523.7nm. 2013 G. Anoop[Anoop G, Cho I H, Suh D W et al. J. Lumin. 2013, 134(3): 390-395.], Wang Lingli[Wang Lingli, Ni Haiyong, Zhang Qiuhong et al. Luminous Journal.2013,34.10] etc. Using traditional oxide powder as raw material, the nitrogen oxide phosphor BaAl _2-x Six _{O 4-x} N _x :Eu ²⁺ was developed through a high-temperature solid-state reaction process.

However, the above-mentioned phosphors and their preparation methods still have room for improvement, especially in terms of the simplicity of the preparation method and the improvement of luminous efficiency, which are still far behind the existing market requirements for green phosphors. Therefore, it is of certain significance to obtain green phosphors with stable physical and chemical properties, high luminous efficiency, and good color rendering under the excitation of ultraviolet and blue light.

Contents of the invention

The technical problem to be solved by the present invention is to provide a rare-earth-doped nitrogen oxide phosphor material and a preparation method thereof. The present invention is a novel nitrogen oxide green phosphor suitable for efficient excitation of blue LED chips, broadens the excitation spectrum, improves Luminous intensity; and breaking through the synthesis conditions of high pressure and ultra-high temperature, obtaining a simple and low-cost preparation technology suitable for large-scale production.

In order to solve the above technical problems, the present invention provides a rare earth-doped nitrogen oxide green phosphor material, the general chemical formula of the nitrogen oxide green phosphor material is: Ba _1-y Ln _x Al _2-xz Si _z O _4-z N _z :yEu ²⁺ (Ln=Y,La,Gd,Lu) where, Ln is at least one of Y, La, Gd, Lu; where 0.05≤x≤0.4; 0.01≤y≤0.4; 0.4≤z≤0.8.

The present invention provides a method for preparing the above-mentioned rare earth-doped oxynitride green fluorescent powder material, using simple substances, oxides or corresponding Salt and Si ₃ N ₄ are raw materials, weighed according to stoichiometric ratio and add flux; after fully grinding, place in sintering furnace at 1100-1400°C to keep warm, cool to room temperature with furnace, take out and add silicon nitride to fully grind , placed in the atmosphere furnace at 1100-1300 ℃ insulation. Cool to room temperature under an ammonia or nitrogen protective atmosphere. After washing with hot water, the rare earth-doped green fluorescent powder is prepared.

As the best embodiment of the present invention, the doped rare earth ion Ln is at least one of Y, La, Gd and Lu.

As a preferred embodiment of the present invention, the optimal concentration of Eu is 0.01≤y≤0.4, the optimal concentration of rare earth doping is 0.05≤x≤0.4, and the optimal concentration of N is 0.4≤z≤0.8.

As the best embodiment of the present invention, the raw materials include one or one of the simple substances, oxides or corresponding salts of Si, Al, Ba and Ln (Ln=Eu, Y, La, Gd, Lu) Mixtures in any proportion of the above.

As the best embodiment of the present invention, the temperature of the first high-temperature calcination is 1100-1400° C., and the time is 2-6 hours.

As the best embodiment of the present invention, the reduction roasting temperature is 1100-1300° C., and the time is 2-9 hours.

As the best embodiment of the present invention, the flux is selected from one or more of NH ₄ F, BaF ₂ , H ₃ BO ₃ and Na ₂ CO ₃ .

As the best embodiment of the present invention, the preparation method of the rare earth-doped oxynitride green phosphor material is characterized in that: the second sintering is carried out in a protective atmosphere, and the protective atmosphere refers to NH _3. A combination of one or more of N ₂ /H ₂ , the ratio of the N ₂ /H ₂ protective atmosphere is: 5≤(N ₂ /H ₂ )≤15.

As the best embodiment of the present invention, the quality of the flux is based on simple substances, oxides or corresponding salts of Si, Al, Ba and Ln (Ln=Eu, Y, La, Gd, Lu) and Si ₃ N ₄ It is 1-15% of the total weight of the mixture formed by raw materials.

The fluorescent powder obtained by the invention has excellent luminous performance. Moreover, this phosphor has a wide effective excitation range and can be effectively excited by light in the 250-470nm band, and a new type of green light-emitting material with high luminous intensity that meets ultraviolet and blue light excitation has been sought.

The beneficial effects of adopting the method of the present invention are: 1. Through the selective addition of rare earth ion doping and fluxing agent, the luminescent characteristics of the phosphor powder are improved, and the excitation segment is wider, and it can be used in ultraviolet, near ultraviolet and blue light regions. 2. The phosphor powder involved in the present invention does not contain sulfur, has stable physical and chemical properties, and solves many shortcomings such as harsh preparation conditions (ultra-high temperature; high nitrogen pressure; high equipment requirements) in the traditional nitrogen (oxide) oxide fluorescent material system. , which reduces the reaction conditions and costs, and lays the foundation for the large-scale industry in the later stage. 3. The phosphor manufacturing method involved in the present invention is simple and feasible, and is convenient for large-scale production.

Description of drawings:

Figure 1 is the excitation spectrum of Ba _0.9 Y _0.1 Al _1.3 Si _0.6 O _3.4 N _0.6 :0.1Eu ²⁺ sample;

Figure 2 is the emission spectrum of Ba _0.9 Y _0.1 Al _1.3 Si _0.6 O _3.4 N _0.6 :0.1Eu ²⁺ sample;

Figure 3 is a graph comparing the excitation spectra of doped rare earth ions Ln ³⁺ (Ln=Y, La, Gd, Lu) with the standard Ba _0.9 Al _1.4 Si _0.6 O _3.4 N _0.6 :0.1Eu ²⁺ phosphor.

Detailed ways

Below in conjunction with accompanying drawing and embodiment the present invention will be further described.

Example 1: According to the chemical formula of Ba _0.9 Y _0.1 Al _1.3 Si _0.6 O _3.4 N _0.6 :0.1Eu ²⁺ , weigh BaCO ₃ 2.7323g, Al ₂ O ₃ 1.0196g, SiO ₂ 0.1386g, Y ₂ O ₃ 0.1737g , Eu ₂ O ₃ 0.2707g, BaCO ₃ , SiO ₂ are analytically pure, Y ₂ O ₃ , Eu ₂ O ₃ purity is 4N and above, and add 5% flux NH ₄ F 0.2329g after mixing and grinding evenly , placed in a high-temperature furnace, uniformly heated from room temperature to 1250°C, kept for 3 hours, then naturally cooled to room temperature, taken out, and added Si ₃ N ₄ 0.3237g to fully grind, placed in N ₂ /H ₂ =10:1 It was kept at 1200° C. for 6 hours in an atmosphere furnace. Cool to room temperature under a nitrogen atmosphere. The product was washed with deionized water at 60°C for 2-3 times, and dried at 120°C to obtain a rare earth-doped green phosphor Ba _0.9 Y _0.1 Al _1.3 Si _0.6 O _3.4 N _0.6 :0.1Eu ²⁺ (ie x=0.1, y=0.1, z=0.6). Its excitation spectrum has a wide excitation peak, and the excitation effect of light with a wavelength in the range of 250nm-470nm is better, so it can be applied to ultraviolet light, near ultraviolet light or blue light LED chips and the like. Its color coordinates are x=0.1861, y=0.5662, and relative brightness is 1.842 (with Ba _0.9 Al _1.4 Si _0.6 O _3.4 N _0.6 :0.1Eu ²⁺ as a standard sample, the excitation and emission spectra are shown in Figures 1 and 2, Example 2 -Embodiment 19 is all like this as a standard sample).

Embodiment 2 - Embodiment 7

Except that the chemical formula composition and stoichiometry of each embodiment in Table 1 are used to weigh raw materials, all the other manufacturing steps are the same as in Example 1, and the chemical composition, color coordinates, and relative brightness are obtained in Table 1.

The chemical formula of table 1 embodiment 1-6 and its color coordinate and relative brightness

Example chemical formula Color coordinates (x,y) relative brightness 1 Ba _0.9 Y _0.1 Al _1.3 Si _0.6 O _3.4 N _0.6 :0.1Eu ²⁺ (0.1861, 0.5662) 1.842 2 Ba _0.9 Y _0.05 Al _1.35 Si _0.6 O _3.4 N _0.6 :0.1Eu ²⁺ (0.1876, 0.5723) 1.757 3 Ba _0.9 Y _0.3 Al _1.1 Si _0.6 O _3.4 N _0.6 :0.1Eu ²⁺ (0.1858, 0.5652) 2.454 4 Ba _0.9 Y _0.325 Al _1.075 Si _0.6 O _3.4 N _0.6 :0.1Eu ²⁺ (0.1832, 0.5656) 2.479 5 Ba _0.9 Y _0.35 Al _1.05 Si _0.6 O _3.4 N _0.6 :0.1Eu ²⁺ (0.1823, 0.5658) 2.734 6 Ba _0.9 Y _0.375 Al _1.025 Si _0.6 O _3.4 N _0.6 :0.1Eu ²⁺ (0.1688, 0.5465) 2.529 7 Ba _0.9 Y _0.4 Al _1.0 Si _0.6 O _3.4 N _0.6 :0.1Eu ²⁺ (0.1744, 0.5557) 2.512

Example 8: According to the chemical formula of Ba _0.9 Lu _0.1 Al _1.3 Si _0.6 O _3.4 N _0.6 :0.1Eu ²⁺ , weigh BaCO ₃ 2.7323g, Al ₂ O ₃ 1.0196g, SiO ₂ 0.1387g, Lu(OH) ₃ 0.0 .3477g, Eu(OH) ₃ 0.3123g, BaCO ₃ , SiO ₂ are analytically pure, Y ₂ O ₃ , Eu ₂ O ₃ purity is 4N and above, and add 10% flux NH ₄ F 0. 4874g After mixing and grinding evenly, put it into a high-temperature furnace, heat it uniformly from room temperature to 1250°C, keep it warm for 3 hours, then cool it down to room temperature naturally and grind it, then fully grind the powder with a certain proportion of Si ₃ N ₄ 0.3237g, and place it under N ₂ /H ₂ =10:1 in an atmosphere furnace at 1200°C for 6 hours. Cool to room temperature under a nitrogen atmosphere. Wash the product with deionized water at 60°C for 2-3 times, and dry it at 120°C to obtain a rare earth-doped green phosphor Ba _0.9 Lu _0.1 Al _1.3 Si _0.6 O _3.4 N _0.6 :0.1Eu ²⁺ (ie x =0.1, y=0.1, z=0.6). Compared with the standard Ba _0.9 Al _1.4 Si _0.6 O _3.4 N _0.6 :0.1Eu ²⁺ phosphor (see Figure 3), it has a wider excitation spectrum, indicating that the doping of rare earth ions significantly improves its luminescence performance and broadens Excitation spectrum, and significantly increased luminous intensity.

The chemical formula of table 2 embodiment 8-11 and its color coordinate and relative brightness

Example chemical formula Color coordinates (x,y) relative brightness 8 Ba _0.9 Lu _0.1 Al _1.3 Si _0.6 O _3.4 N _0.6 :0.1Eu ²⁺ (0.1763, 0.5578) 1.684 9 Ba _0.9 Gd _0.1 Al _1.3 Si _0.6 O _3.4 N _0.6 :0.1Eu ²⁺ (0.1758, 0.5564) 1.564 10 Ba _0.9 La _0.1 Al _1.3 Si _0.6 O _3.4 N _0.6 :0.1Eu ²⁺ (0.1836, 0.5586) 1.532

Embodiment 8 - Embodiment 10

Except that the rare earth doping elements of each embodiment in Table 2 are different, the rest of the manufacturing steps are the same as in Example 8, and the obtained chemical composition and relative brightness are shown in Table 2.

Example 11: According to the chemical formula of Ba _0.9 Y _0.1 Al _1.3 Si _0.6 O _3.4 N _0.6 :0.1Eu ²⁺ , weigh BaCO ₃ 2.7323g, Al ₂ O ₃ 1.0196g, SiO ₂ 0.1386g, Y ₂ O ₃ 0.1736g , Eu ₂ O ₃ 0.2707g, BaCO ₃ , SiO ₂ are analytically pure, Y ₂ O ₃ , Eu ₂ O ₃ purity is 4N and above, and after adding 10% flux BaF ₂ 0.4884g and mixing evenly, Put it into a high-temperature furnace, heat it uniformly from room temperature to 1250°C, keep it warm for 3 hours, then cool it down to room temperature naturally and grind it, then grind the powder with a certain proportion of Si ₃ N ₄ 0.3237g, and place it in an ammonia atmosphere furnace Incubate at 1200°C for 6 hours. Cool to room temperature under an ammonia protective atmosphere. Wash the product with water at 60°C for 2-3 times, and dry it at 120°C to obtain a rare earth-doped green phosphor Ba _0.9 Y _0.1 Al _1.3 Si _0.6 O _3.4 N _0.6 :0.1Eu ²⁺ (that is, x= 0.1, y=0.1, z=0.6). Taking Ba _0.9 Al _1.4 Si _0.6 O _3.4 N _0.6 :0.1Eu ²⁺ as the standard sample, different types of fluxes have different effects on increasing the luminous intensity of phosphors. Among them, the effect of NH ₄ F on phosphors most obvious.

The chemical formula of table 3 embodiment 11-13 and its color coordinate and relative brightness

Example chemical formula Flux type Color coordinates (x, y) relative brightness 11 Ba _0.9 Y _0.1 Al _1.3 Si _0.6 O _3.4 N _0.6 :0.1Eu ²⁺ BaF ₂ (0.1773, 0.5627) 1.274 12 Ba _0.9 Y _0.1 Al _1.3 Si _0.6 O _3.4 N _0.6 :0.1Eu ²⁺ H ₃ BO ₃ (0.1862, 0.5675) 1.620 13 Ba _0.9 Y _0.1 Al _1.3 Si _0.6 O _3.4 N _0.6 :0.1Eu ²⁺ Na ₂ CO ₃ (0.1749, 0.5587) 1.256

Embodiment 11 - Embodiment 13

Except that the types of flux in each embodiment in Table 3 are different, the rest of the manufacturing steps are the same as in Example 11, and the obtained chemical composition and relative brightness are shown in Table 3.

Example 14: According to the chemical formula of Ba _0.99 Y _0.1 Al _1.3 Si _0.6 O _3.4 N _0.6 :0.01Eu ²⁺ , weigh BaCO ₃ 3.0055g, Al ₂ O ₃ 1.0196g, SiO ₂ 0.1386g, Y(NO ₃ ) ₃ 0.4230g, Eu(NO ₃ ) ₃ 0.0520g, BaCO ₃ , SiO ₂ are analytically pure, Y ₂ O ₃ , Eu ₂ O ₃ purity is 4N or above, and add 10% flux H ₃ BO ₃ 0.4962 After the g is mixed and ground evenly, put it into a high-temperature furnace, uniformly heat it from room temperature to 1250°C, keep it warm for 3 hours, then cool it down to room temperature naturally and grind it, then fully grind the powder with a certain proportion of Si ₃ N ₄ 0.3237g, place N2/H2=10:1 atmosphere furnace at 1200 ℃ for 6 hours. Cool to room temperature under a nitrogen atmosphere. Wash the product with water at 60°C for 2-3 times, and dry it at 120°C to obtain a rare earth-doped green phosphor Ba _0.99 Y _0.1 Al _1.3 Si _0.6 O _3.4 N _0.6 :0.01Eu ²⁺ (that is, x= 0.1, y=0.01, z=0.6). Taking Ba _0.9 Al _1.4 Si _0.6 O _3.4 N _0.6 :0.1Eu ²⁺ as the standard sample, different concentrations of Eu and N ions have different effects on the luminous intensity of the phosphor.

The chemical formula of table 4 embodiment 14-19 and its color coordinate and relative brightness

Example chemical formula Color coordinates (x, y) relative brightness 14 Ba _0.99 Y _0.1 Al _1.3 Si _0.6 O _3.4 N _0.6 :0.01Eu ²⁺ (0.1863, 0.5387) 1.448 15 Ba _0.96 Y _0.1 Al _1.3 Si _0.6 O _3.4 N _0.6 :0.04Eu ²⁺ (0.1834, 0.5591) 2.051 16 Ba _0.8 Y _0.1 Al _1.3 Si _0.6 O _3.4 N _0.6 :0.2Eu ²⁺ (0.1835, 0.5675) 1.428 17 Ba _0.6 Y _0.1 Al _1.3 Si _0.6 O _3.4 N _0.6 :0.4Eu ²⁺ (0.1722, 0.5576) 1.264 18 Ba _0.9 Y _0.1 Al _1.5 Si _0.4 O _3.6 N _0.4 :0.1Eu ²⁺ (0.1843, 0.5624) 1.258 19 Ba _0.9 Y _0.1 Al _1.1 Si _0.8 O _3.2 N _0.8 :0.1Eu ²⁺ (0.1758, 0.5592) 1.471

Embodiment 14 - Embodiment 19

Except that the chemical formula composition and stoichiometry of each embodiment in Table 4 are used to weigh raw materials, all the other manufacturing steps are the same as in Example 14, and the chemical composition and relative brightness are shown in Table 4.

Claims (10)

1. A rare earth-doped oxynitride green phosphor material, characterized in that: the general chemical formula of the oxynitride phosphor is Ba _1-y Ln _x Al _2-xz Si _z O _4-z N _z : yEu ²⁺ (Ln=Y,La,Gd,Lu). 2. The rare earth-doped oxynitride green phosphor material according to claim 1, characterized in that the doped rare earth ion Ln is at least one of Y, La, Gd, and Lu. 3. The rare earth-doped nitrogen oxide green phosphor material according to claim 1, characterized in that in order to obtain high-quality green light, the optimal concentration of Ln doping is 0.05≤x≤0.4, and the optimal concentration of Eu is 0.01≤ y≤0.4, the optimal concentration of N is 0.4≤z≤0.8. 4. a kind of preparation method of the oxynitride green phosphor material of rare earth doping as claimed in claim 1, is characterized in that comprising the following steps: (a) With Si, Al, Ba and Ln (Ln=Eu, Y, La, Gd, Lu) elemental, oxide or corresponding salts and Si ₃ N ₄ as raw materials, according to the chemical formula of claim 1 composition And stoichiometrically weigh the corresponding raw materials; (b) adding flux to the raw material from which Si ₃ N ₄ has been removed, grinding it evenly after mixing, and roasting the mixed material after grinding at high temperature; (c) Grinding the above-mentioned calcined product, adding Si ₃ N ₄ for mixing and grinding evenly, and roasting the ground mixed material at a high temperature in a reducing atmosphere; (d) After post-treatment, the final product nitrogen oxide green fluorescent powder is obtained. 5. The method according to claim 4, characterized in that in step a), the raw materials include simple substances, oxides or One or more than one of the corresponding salts in any proportion of the mixture. 6. The method according to claim 5, characterized in that the high-temperature calcination in step b) is performed at a temperature of 1100-1400° C. for 2-6 hours. 7. The method according to claim 4, characterized in that in step c), the reduction roasting temperature is 1100-1300°C, and the time is 2-9 hours. 8. The preparation method of rare earth-doped oxynitride green phosphor material according to claim 4, characterized in that: the flux is selected from NH ₄ F, BaF ₂ , H ₃ BO ₃ and Na ₂ CO ₃ one or more of . 9. The preparation method of rare earth-doped oxynitride green phosphor material as claimed in claim 4, characterized in that: the second sintering is carried out in a protective atmosphere, and the protective atmosphere refers to NH ₃ , A combination of one or more of N ₂ /H ₂ , the ratio of the N ₂ /H ₂ protective atmosphere is: 5≤(N ₂ /H ₂ )≤15. 10. the preparation method of the oxynitride green phosphor material of rare earth doping as claimed in claim 4 is characterized in that: the quality of described flux is represented by Si, Al, Ba and Ln (Ln=Eu, Y, La , Gd, Lu) simple substances, oxides or corresponding salts and Si ₃ N ₄ as raw materials of the mixture formed by the total weight of 1-15%.