TWI534245B - Phosphor material and the manufacturing method thereof - Google Patents

Description

Fluorescent material and preparation method thereof

A nitride fluorescent material having the formula (M _1-xy A _x )(Al _1-x Si _1+x )N ₃ :Eu _y , wherein M=Mg, Ca, Sr, Ba, Zn ; A = Li, Na; 0 < y < 0.5 and 0 < x < 0.5.

The principle of light-emitting diode (LED) is to use energy difference between the n-type semiconductor and the p-type semiconductor to release energy in the form of light. This principle of illumination is different from incandescent lamps. The principle of heat generation, so the light-emitting diode is called a cold light source.

In addition, the light-emitting diode has the advantages of high durability, long life, light weight, low power consumption, etc., so the current lighting market has high hopes for the light-emitting diode, and it is gradually replaced as a new generation of lighting tools. Light source, and is used in various fields, such as traffic signs, backlight modules, street lighting, medical equipment, etc.

Generally, white light is generated by a blue LED emitting Cerium-doped yttrium aluminum garnet (YAG:Ce) phosphor powder to produce yellow fluorescent light and then mixed to form white light, but such white light emitting diode For cool white light, its color rendering is low. At present, in addition to using blue diodes with yellow phosphors, white light-emitting diodes also have blue LEDs with green, red phosphors, and ultraviolet light-emitting diodes (UV-LEDs) with blue-green red three. The color fluorescent powder and the like are mixed into a white light mode, wherein the UV-LED and the three-color fluorescent powder have better color rendering properties, so the development of blue, green and red fluorescent powder suitable for ultraviolet light excitation is an important research topic at present.

A nitride fluorescent material having the formula (M _1-xy A _x )(Al _1-x Si _1+x ) N ₃ :Eu _y , wherein M=Mg, Ca, Sr, Ba, Zn ; A = Li, Na; 0 < y < 0.5 and 0 < x < 0.5.

Figure 1 is a X-ray powder diffraction pattern of a Ca _0.995 Al _1-x Ga _x SiN ₃ :Eu _0.005 (x = 0.00-0.25) red nitride phosphor prepared in accordance with a first embodiment of the present invention.

Fig. 2 is a graph showing the excitation spectrum of Ca _0.995 Al _1-x Ga _x SiN ₃ :Eu _0.005 (x = 0.00-0.25) red nitride phosphor prepared in the first embodiment of the present invention.

Figure 3 is a graph showing the emission spectrum of Ca _0.995 Al _1-x Ga _x SiN ₃ :Eu _0.005 (x = 0.00-0.25) red nitride phosphor prepared in the first embodiment of the present invention.

Figure 4 is a normalized emission spectrum of a red nitride phosphor of Ca _0.995 Al _1-x Ga _x SiN ₃ :Eu _0.005 (x = 0.00-0.25) prepared in the first embodiment of the present invention.

Figure 5 is a CIE chromaticity coordinate diagram showing the Ca _0.995 Al _1-x Ga _x SiN ₃ :Eu _0.005 (x = 0.00-0.25) red nitride phosphor prepared in the first embodiment of the present invention.

Figure 6 shows a red nitride phosphor powder prepared by the first embodiment of the present invention (Ca _0.995-x Li _x )(Al _1-x Si _1+x )N ₃ :Eu _0.005 (x=0.00-0.15) A comparison of the relative intensity of the intensity of the light as a function of temperature.

Figure 7 shows a red nitride phosphor powder prepared by the first embodiment of the present invention (Ca _0.995-x Li _x )(Al _1-x Si _1+x )N ₃ :Eu _0.005 (x=0.00-0.15) X-ray powder diffraction pattern.

Figure 8 shows a red nitride phosphor powder prepared by the second embodiment of the present invention (Ca _0.995-x Li _x )(Al _1-x Si _1+x )N ₃ :Eu _0.005 (x=0.00-0.15) Excitation spectrum.

Figure 9 shows a red nitride phosphor powder prepared by the second embodiment of the present invention (Ca _0.995-x Li _x )(Al _1-x Si _1+x )N ₃ :Eu _0.005 (x=0.00-0.15) Radiation spectrum.

Figure 10 shows a red nitride phosphor powder prepared by the second embodiment of the present invention (Ca _0.995-x Li _x )(Al _1-x Si _1+x )N ₃ :Eu _0.005 (x=0.00-0.15) Normalized radiographic spectra.

Figure 11 shows a red nitride phosphor (Ca _0.995-x Li _x )(Al _1-x Si _1+x )N ₃ :Eu _0.005 (x=0.00-0.15) prepared in accordance with a second embodiment of the present invention. A comparison of the relative intensity of the intensity of the powder as a function of temperature.

Figure 12 is a schematic view showing the ionic bonding strength of the second embodiment of the present invention.

The present invention discloses a nitride fluorescent material. In order to make the description of the present invention more detailed and complete, please refer to the following description and the drawings of FIG. 1 to FIG.

A first embodiment of the present invention discloses a nitride fluorescent material having the formula M _1-y (Al _1-x Ga _x )SiN ₃ :Eu _y , wherein M=Mg, Ca, Sr, Ba, Zn; <y<0.5, 0<x<0.5, this fluorescent material mainly uses europium (Eu) as a light-emitting center. The preparation method comprises: mixing a nitride containing a group of elements, a nitride containing aluminum, a nitride containing ruthenium, a nitride containing ruthenium (Eu), and gallium nitride into a mixture and heating and sintering to form a nitrogen. Fluorescent material.

In the following first embodiment of the present invention, a Ca _0.995 Al _1-x Ga _x SiN ₃ :Eu _0.005 phosphor powder formulation and preparation process will be described, and a comparative example in which no gallium nitride is prepared is provided, and samples 1 to 5 are provided. Add an appropriate amount of gallium nitride, which is x=0.05, 0.1, 0.15, 0.2 and 0.25, respectively.

First, the production comparison example: Ca _0.995 Al _1-x Ga _x SiN ₃ :Eu _0.005 , x=0.00

The raw materials used include Ca ₃ N ₂ , AlN, Si ₃ N ₄ and EuN, and an appropriate amount of the above raw materials is weighed and uniformly mixed and ground in a mortar, and then subjected to solid state synthesis at a temperature of 1700 ° C and a nitrogen pressure of 0.48 MPa. In the environment of sintering for 4 hours, a comparative example of the red phosphor of the first embodiment of the invention can be obtained. In one embodiment, the sintering temperature may range from 1500 to 2200 ° C and the sintered nitrogen pressure may range from 0.3 to 1.0 MPa.

2. Samples 1 to 5 were prepared: Ca _0.995 Al _1-x Ga _x SiN ₃ :Eu _0.005 , which was added with an appropriate amount of gallium nitride, which were x = 0.05, 0.1, 0.15, 0.2 and 0.25, respectively.

The raw materials used include Ca ₃ N ₂ , AlN, Si ₃ N ₄ and EuN, and an appropriate amount of gallium nitride is added, and an appropriate amount of the above raw materials is weighed and uniformly mixed and ground in a mortar, and then placed in a solid state by a solid state synthesis method. The red fluorescent powder samples 1 to 5 of the first embodiment of the present invention were obtained by sintering at 1800 ° C for 4 hours under an atmosphere of a nitrogen pressure of 0.48 MPa. In one embodiment, the sintering temperature may range from 1500 to 2200 ° C and the sintered nitrogen pressure may range from 0.3 to 1.0 MPa.

1 is a diffraction diagram of an X-ray powder of a Ca _0.995 Al _1-x Ga _x SiN ₃ :Eu _0.005 (x=0.00-0.25) red nitride phosphor prepared according to a first embodiment of the present invention, as shown in FIG. As shown, comparing the phosphor powder synthesized by the present invention with the X-ray powder diffraction pattern of the standard CaAlSiN ₃ compound, the phosphor powder synthesized by the present invention can be identified as a pure phase.

2 is an excitation spectrum diagram of a Ca _0.995 Al _1-x Ga _x SiN ₃ :Eu _0.005 (x=0.00-0.25) red nitride phosphor prepared in the first embodiment of the present invention, as shown in FIG. The sample is effectively excited by the ultraviolet-blue light wafer. In one embodiment, the excitation wavelength can be between 330 and 550 nm and can be generated by a light emitting diode or plasma.

3 is a radiation spectrum diagram showing a Ca _0.995 Al _1-x Ga _x SiN ₃ :Eu _0.005 (x=0.00-0.25) red nitride phosphor prepared in the first embodiment of the present invention; FIG. 4 shows the present invention. The normalized emission spectrum of Ca _0.995 Al _1-x Ga _x SiN ₃ :Eu _0.005 (x=0.00-0.25) red nitride phosphor prepared in the first embodiment, as shown in FIG. 3 and FIG. The highest peak of the emission spectrum of the sample is 646, 640, 640, 639, 633 and 632 nm according to x=0.00, 0.05, 0.10, 0.15, 0.20 and 0.25, respectively. The highest peak shifts to short wavelength, and the half-height of each peak The order is 91, 94, 97, 98, 103 and 107 nm. In an embodiment, the emission wavelength can be between 570 and 750 nm.

Figure 5 is a CIE chromaticity coordinate diagram of a Ca _0.995 Al _1-x Ga _x SiN ₃ :Eu _0.005 (x=0.00-0.25) red nitride phosphor prepared in the first embodiment of the present invention, as shown in Figure 5 As shown, as the amount of added gallium nitride increases, the chromaticity coordinates are shifted toward the yellow light region.

Figure 6 is a graph showing the relative intensity of the light-emitting intensity of Ca _0.995 Al _1-x Ga _x SiN ₃ :Eu _0.005 (x=0.00-0.25) red nitride phosphor prepared according to the first embodiment of the present invention as a function of temperature. Comparing the graphs, as shown in Fig. 6, the calculated light intensity at 300 ° C is 73, 83, 82, 84, 85 and 90% relative to the room temperature, compared to the comparative examples, samples 1 to 5 The addition of gallium nitride to the starting material to synthesize red nitride phosphor powder can effectively improve the thermal stability.

A second embodiment of the present invention discloses a nitride fluorescent material having the formula (M _1-xy A _x )(Al _1-x Si _1+x )N ₃ :Eu _y , wherein M=Mg, Ca, Sr, Ba, Zn; A=Li, Na; 0<y<0.5 and 0<x<0.5. This fluorescent material mainly uses europium (Eu) as the luminescent center. The preparation method comprises: mixing a nitride containing a group of elements, a nitride containing aluminum, a nitride containing ruthenium, a nitride containing ruthenium (Eu), and lithium nitride into a mixture and heating and sintering to form a nitrogen. a fluorescent material having the formula (M _1-xy A _x )(Al _1-x Si _1+x )N ₃ :Eu _y , wherein M=Mg, Ca, Sr, Ba, Zn; A =Li, Na; 0 < y < 0.5 and 0 < x < 0.5. In one embodiment, the content of lithium, aluminum and cerium is a balanced valence.

In the following second embodiment of the present invention, a (Ca _0.995-x Li _x )(Al _1-x Si _1+x )N ₃ :Eu _0.005 phosphor powder formulation and preparation process will be described, and a lithium nitride is not added. In the comparative examples prepared, samples 1 to 3 were added with an appropriate amount of lithium nitride and the aluminum and cerium contents were adjusted as a valence balance, wherein x=0.03, 0.09 and 0.15 were prepared as follows:

I. Comparative Example: Production (Ca _0.995-x Li _x )(Al _1-x Si _1+x )N ₃ :Eu _0.005 , x=0.00.

The raw materials used include Ca ₃ N ₂ , AlN, Si ₃ N ₄ and EuN, and an appropriate amount of the above raw materials is weighed and uniformly mixed and ground in a mortar, and then subjected to solid state synthesis at a temperature of 1700 ° C and a nitrogen pressure of 0.48 MPa. In the environment of sintering for 4 hours, a comparative example of the red phosphor of the second embodiment of the invention is obtained. In one embodiment, the sintering temperature may range from 1500 to 2200 ° C and the sintered nitrogen pressure may range from 0.3 to 1.0 MPa.

2. Prepare samples 1 to 3: (Ca _0.995-x Li _x )(Al _1-x Si _1+x )N ₃ :Eu _0.005 , which is added with an appropriate amount of lithium nitride, respectively x=0.03, 0.09 and 0.15 .

The raw materials used include Ca ₃ N ₂ , AlN, Si ₃ N ₄ and EuN, and an appropriate amount of lithium nitride is added to adjust the aluminum and cerium content as a valence balance, and an appropriate amount of the above raw materials is uniformly mixed and ground in a mortar. The red fluorescent powder samples 1 to 3 of the second embodiment of the present invention were obtained by solid state synthesis at a temperature of 1700 ° C and a nitrogen pressure of 0.48 MPa for 4 hours. In one embodiment, the sintering temperature may range from 1500 to 2200 ° C and the sintered nitrogen pressure may range from 0.3 to 1.0 MPa.

Figure 7 shows a red nitride phosphor powder prepared by the second embodiment of the present invention (Ca _0.995-x Li _x )(Al _1-x Si _1+x )N ₃ :Eu _0.005 (x=0.00-0.15) The X-ray powder diffraction pattern, as shown in Fig. 7, compares the phosphor powder synthesized by the present invention with the X-ray powder diffraction pattern of the standard CaAlSiN ₃ compound, and the phosphor powder synthesized by the present invention can be identified as a pure phase.

Figure 8 shows a red nitride phosphor powder prepared by the second embodiment of the present invention (Ca _0.995-x Li _x )(Al _1-x Si _1+x )N ₃ :Eu _0.005 (x=0.00-0.15) The excitation spectrum, as shown in Figure 8, is effectively excited by the UV-blue wafer. In one embodiment, the excitation wavelength can be between 330 and 550 nm and can be generated by a light emitting diode or plasma.

Figure 9 shows a red nitride phosphor powder prepared by the second embodiment of the present invention (Ca _0.995-x Li _x )(Al _1-x Si _1+x )N ₃ :Eu _0.005 (x=0.00-0.15) Radiation spectrum; Figure 10 shows (Ca _0.995-x Li _x )(Al _1-x Si _1+x )N ₃ :Eu _0.005 (x=0.00-0.15) red nitride prepared according to the second embodiment of the present invention The normalized emission spectrum of the phosphor powder, as shown in Fig. 9 and Fig. 10, the highest peak of the emission spectrum of the sample is 644, 643, 639 and 633 nm, respectively, with x=0.00, 0.03, 0.09 and 0.15, respectively. The wavelength is shifted to a short wavelength, and the half-height and width of each peak are sequentially 93, 95, 103, and 115 nm. In an embodiment, the emission wavelength can be between 570 and 750 nm.

Figure 11 shows a red nitride phosphor powder prepared by the second embodiment of the present invention (Ca _0.995-x Li _x )(Al _1-x Si _1+x )N ₃ :Eu _0.005 (x=0.00-0.15) The comparison of the relative intensity of the light intensity with temperature is shown in Figure 11. After calculation, the intensity of the light at 300 °C is 73, 83, 82, 84, 85 and 90% relative to the room temperature. Compared with the comparative example, the samples 1 to 3 were added with gallium nitride to synthesize a red nitride phosphor in the starting material, which was effective for improving thermal stability.

The change in thermal characteristics of Samples 1-3 of the second embodiment of the present invention can be explained by the ionic bond strength, and a schematic view thereof is shown in FIG. Figure 12(b) is a schematic diagram of CaAlSiN ₃ in which N ^{3 - is} bonded to two Ca ²⁺ , and when Eu ²⁺ enters the crystal lattice, it can replace any Ca ²⁺ lattice. Figure 12 (a) is a La ³⁺ /Al ³⁺ substitution. Since the valence of La ³⁺ is greater than Ca ²⁺ , the bond between La ³⁺ -N ^3- is stronger, making the electron cloud of N ³ tend to It is bonded to La ³⁺ , so its electron cloud density bonded to another Ca ^{2+ is} small and the bond is weak. When Eu ^{2+ is} substituted for Ca ²⁺ , the bond between Eu-N is weak, resulting in It is susceptible to thermal disturbance at high temperatures, and the fluorescence intensity decreases rapidly, that is, the thermal stability is poor. On the contrary, as shown in Fig. 12(c), if Li ⁺ /Si ^{4+ is} substituted in the second embodiment of the present invention, since the Li ⁺ valence is smaller than Ca ²⁺ , the bond with N ³ is compared. Weak, so the density of electrons bound by N ^3- and Ca ^{2+ is} large, that is, the Ca ²⁺ -N ^3- bond is strong. When Eu ^{2+ is} substituted for Ca ²⁺ , it is not easily affected by thermal disturbance. Its thermal stability is relatively good.

The above figures and descriptions are only corresponding to specific embodiments, however, the elements, embodiments, design criteria, and technical principles described or disclosed in the various embodiments are inconsistent, contradictory, or difficult to implement together. In addition, we may use any reference, exchange, collocation, coordination, or merger as required. Although the invention has been described above, it is not intended to limit the scope of the invention, the order of implementation, or the materials and process methods used. Various modifications and variations of the present invention are possible without departing from the spirit and scope of the invention.

Claims (8)

A nitride fluorescent material having the formula (M _1-xy A _x )(Al _1-x Si _1+x )N ₃ :Eu _y , wherein M=Mg, Ca, Sr, Ba, Zn ; A = Li, Na; 0 < y < 0.5 and 0 < x < 0.5. The nitride fluorescent material according to claim 1, wherein the fluorescent material mainly has europium (Eu) as a light-emitting center, and/or the fluorescent material emits red light. The nitride fluorescent material according to claim 1, wherein the fluorescent material is excited by light having a wavelength of 330 to 550 nm, and/or the fluorescent material has an emission wavelength of 570 to 750 nm. The nitride fluorescent material of claim 3, wherein the light is generated by a light emitting diode or a plasma. A method for preparing a nitride fluorescent material, comprising: mixing a nitride containing a group of elements, a nitride containing aluminum, a nitride containing germanium, a nitride containing germanium (Eu), and lithium nitride Forming a mixture; and heating and sintering to form a nitride fluorescent material, the fluorescent material having the formula (M _1-xy A _x )(Al _1-x Si _1+x )N ₃ :Eu _y , wherein M=Mg, Ca, Sr, Ba, Zn; A = Li, Na; 0 < y < 0.5 and 0 < x < 0.5. The method for preparing a nitride fluorescent material according to claim 5, wherein the content of lithium, aluminum and lanthanum is a balanced valence. The method for preparing a nitride fluorescent material according to claim 5, wherein the temperature of the sintering environment is 1500-2200 ° C, and/or the nitrogen pressure of the sintering environment is 0.3-1.0 MPa. a method for preparing a nitride fluorescent material according to claim 5, wherein The preparation method can be a solid state synthesis method.