High-color-purity fluorescent powder as well as preparation method and application thereof

Abstract

The invention provides high-color-purity fluorescent powder as well as a preparation method and application thereof, and belongs to the technical field of fluorescent materials. According to the high-color-purity fluorescent powder disclosed by the invention, the luminescent spectrum conversion from blue to red of the fluorescent powder can be realized in the same system by controlling the sintering time. The obtained blue fluorescent powder can be combined with a near ultraviolet chip to realize a white light LED, and the obtained high-color-purity red fluorescent powder can be combined with a blue light chip to be widely applied to the field of white light LED illumination or laser display. According to the high-color-purity fluorescent powder, the thermal stability of the fluorescent powder at the working temperature is improved through Mg < 2 + > partial substitution.

Description

Technical Field

[0001] The present invention relates to the technical field of fluorescent materials, and particularly to a high-color-purity phosphor and a preparation method and application thereof. Background Art

[0002] Based on LED chip technology, phosphor-converted white LEDs (Pc-LEDs) are widely used in the fields of lighting and display due to their high energy efficiency and good color rendering. In addition, in laser displays, blue lasers combined with red phosphors can effectively suppress speckle and improve visual safety. However, existing phosphors still have deficiencies in terms of brightness and color purity, restricting the further development of Pc-LED and laser phosphor display technologies. Therefore, the development of phosphors with high color purity, high stability, and high brightness is of great significance for promoting new-generation lighting and advanced display technologies. Summary of the Invention

[0003] The object of the present invention is to provide a high-color-purity phosphor and a preparation method and application thereof, which have high brightness, high color purity, and high stability.

[0004] To achieve the above object of the invention, the present invention provides the following technical solutions: The present invention provides a high-color-purity phosphor with a chemical composition of Ca 3-x-y Mg x Al2O6: yEu 2+ , where x and y represent mole fractions, 0 ≤ x ≤ 0.5, and 0 < y ≤ 0.02.

[0005] Preferably, x = 0.1 - 0.4 and y = 0.005 - 0.018.

[0006] Preferably, x = 0.2 - 0.3 and y = 0.01 - 0.015.

[0007] The present invention provides a preparation method for the high-color-purity phosphor described in the above technical solution, including the following steps: According to the stoichiometric ratio of each element required in Ca 3-x-y Mg x Al2O6: yEu 2+ , mix and grind the required raw materials to obtain a mixed material; when x = 0, the raw materials are a calcium source, an aluminum source, and an europium source, and when 0 < x ≤ 0.5, the raw materials are a calcium source, a magnesium source, an aluminum source, and an europium source; Calcine the mixed material in a reducing atmosphere, and then grind it to obtain the high-color-purity phosphor.

[0008] Preferably, the calcium source includes calcium carbonate, calcium oxide, or calcium nitrate; The magnesium source includes magnesium carbonate, magnesium oxide, or magnesium nitrate; The aluminum source includes elemental aluminum, alumina, or aluminum nitrate-containing compounds; The europium source includes europium oxide or europium carbonate-containing compounds.

[0009] Preferably, the reducing atmosphere is provided by a first gas, a second gas, or carbon powder; the first gas is CO; the second gas is a mixed gas composed of 10% hydrogen and 90% nitrogen by volume percentage; the calcination temperature is 1300 - 1400 °C.

[0010] Preferably, when x = 0, the calcination time is 2 - 4 h, or the calcination time is 8 - 12 h; When the calcination time is 2 - 4 h, the high color purity phosphor is a blue phosphor; when the excitation peak of this blue phosphor is 240 - 400 nm, the emission peak is 380 - 550 nm; When the calcination time is 8 - 12 h, the high color purity phosphor is a red phosphor; when the excitation peak of this red phosphor is 240 - 630 nm, the emission peak is 550 - 800 nm.

[0011] Preferably, when 0 < x ≤ 0.5, the calcination time is 8 - 12 h, and the high color purity phosphor is a red phosphor; when the excitation peak of this red phosphor is 240 - 630 nm, the emission peak is 550 - 800 nm.

[0012] The present invention provides the application of the high color purity phosphor described in the above technical solution or the high color purity phosphor prepared by the preparation method described in the above technical solution in a phosphor-converted white light-emitting diode or LED display, where x = 0 in the high color purity phosphor.

[0013] The present invention provides the application of the high color purity phosphor described in the above technical solution or the high color purity phosphor prepared by the preparation method described in the above technical solution in laser display, where 0 < x ≤ 0.5 in the high color purity phosphor.

[0014] [[ID=​​​​​​​​In the high-purity phosphor provided by this invention, when x=0, the high-purity phosphor of this invention has a cubic crystal system, and the crystal structure includes six Ca lattice sites with different coordination environments, namely: Ca1 (coordination number = 6), Ca2 (coordination number = 6), Ca3 (coordination number = 6), Ca4 (coordination number = 9), Ca5 (coordination number = 8) and Ca6 (coordination number = 7). The 5d energy level is influenced by the host lattice; therefore, the various Ca ion sites in the Ca3Al2O6 host lattice provide different Eu levels. 2+ Local environment.

[0016] When Eu 2+ Replace Ca 2+ This invention enables the phosphor's emission spectrum transition from blue to red within the same system by controlling the sintering time. The resulting blue phosphor can be combined with near-ultraviolet chips to realize white LEDs, while the resulting high-purity red phosphor can be combined with blue chips for widespread application in white LED lighting or display fields.

[0017] When x=0 and the calcination time is 2~4h, the optimal excitation peak of the blue phosphor prepared by this invention is 240-400nm, and the strongest emission peak is 380-550nm. The 240-400nm laser spectrum matches the near-ultraviolet chip. The FWHM of this blue phosphor is approximately 53nm, and the CIE x=0.1493, exhibiting high color purity.

[0018] When x=0 and the calcination time is 8~12h, the optimal excitation peak of the red phosphor prepared by this invention is 240-630 nm, and the strongest emission peak is 550-800 nm. Among them, the optimal excitation peak is located at 450~480 nm, which matches the blue light chip.

[0019] In the high-purity phosphor provided by this invention, when x=0, the Ca3Al2O6 system has 6 different Ca... 2+ Ion lattice sites. When Eu 2+ Doping and substituting Ca 2+ At this time, the Ca4, Ca5, and Ca6 lattice sites with larger coordination numbers and longer bond lengths will be selected first. According to crystal field theory, the larger the coordination number, the longer the bond length, and the shorter the wavelength, thus emitting blue light. However, observing the crystal structure along the

[111] crystal direction, all Ca1-3 are located on the Ca chain with more space around them, while three-quarters of the Ca4, Ca5, and Ca6 ions are located in chains containing both Ca and Al ions, leaving less space around them. Therefore, as the reaction time increases, Eu... 2+ It tends to enter the (Ca1-3O)6 lattice site, which can provide a larger strain space. Therefore, the emission spectrum changes from blue to red.

[0020] In the high-color-purity phosphor provided by the present invention, when 0 < x ≤ 0.5, the optimal excitation peak of the red phosphor is 240 - 630 nm, and the strongest emission peak is 550 - 800 nm. Among them, the optimal excitation peak is located at 450 - 480 nm, which matches the blue light chip. When x = 0.4 and y = 0.02, the CIEx coordinate value is 0.7002, showing a relatively high color purity.

[0021] When 0 < x ≤ 0.5, the red phosphor of the present invention changes the chemical strain of the local coordination environment of Eu through the substitution of Mg 2+ and effectively improves the reduction efficiency of Eu ions. 2+ When 0 < x ≤ 0.5, the red phosphor of the present invention reduces the depth of the oxygen vacancy electron trap existing in the lattice through partial substitution of Mg

[0022] 2+ Under the excitation of blue light at 460 nm, the oxygen vacancy acts as a trap to capture electrons, and transfers the electrons to the 5f energy level of Eu 2+ ions under a certain thermal perturbation, and further transfers them to the 4f energy level through the 5d energy level, thereby improving the thermal stability of the phosphor at the working temperature.

[0023] When 0 < x ≤ 0.5, the present invention adjusts the proportion of Ca in the matrix to change the chemical strain of the local environment of the [Ca / Mg / EuO6] octahedron, and enhances the reduction degree of Eu. During the heat treatment process, oxygen atoms in the lattice will脱离晶格形成氧空位,形成缺陷能级。当Eu 2+ When the concentration of Eu remains unchanged, the increase of x gradually reduces the trap depth of the oxygen vacancy defect energy level. When the environmental temperature rises, the electrons captured by the shallower defect energy level are more easily released to compensate for the thermal quenching of the phosphor at high temperatures. When the temperature reaches 150 o °C, the thermal stability of the phosphor with x = 0.4 is 2.47 times that of x = 0. When x = 0.4, with the increase of the doping content of Eu 2+ the chromaticity coordinate CIEx of the phosphor gradually increases, reflecting the high color purity of the phosphor. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 XRD characterization diagram of the blue phosphor prepared in Example 1; Figure 2 Excitation and emission spectra diagram of the blue phosphor prepared in Example 1; Figure 3 CIE coordinate diagram of the blue phosphor prepared in Example 1; Figure 4 ​The XRD characterization diagram of the red phosphor prepared in Example 2; Figure 5 The excitation and emission spectra of the red phosphor prepared in Example 2 are shown below. Figure 6 CIE coordinate diagram of the red phosphor prepared in Example 2; Figure 7 The emission spectrum of the blue phosphor prepared in Example 1 as a function of sintering time under an excitation wavelength of 334 nm; Figure 8 The emission spectrum of the red phosphor prepared in Example 2 as a function of sintering time under an excitation wavelength of 460 nm; Figure 9 The XRD diffraction patterns of the red phosphors prepared in Examples 3-5 are shown below. Figure 10 The emission spectra of the red phosphors prepared in Examples 2-5 under 460 nm blue light excitation at room temperature are shown. Figure 11 The chromaticity coordinate diagrams of the red phosphors prepared in Examples 4-5 and Example 2; Figure 12 The emission spectrum of the red phosphor prepared in Example 4 under 460 nm blue light excitation as a function of temperature; Figure 13 The emission spectrum of the red phosphor prepared in Example 2 under 460 nm blue light excitation as a function of temperature; Figure 14 A comparison of the emission spectral intensity changes of the red phosphors prepared in Example 4 and Example 2 under 460nm blue light excitation as a function of temperature; Figure 15 The graph shows the irradiation energy variation of the red phosphor prepared in Example 5 under blue laser excitation of different powers. Detailed Implementation

[0025] In this invention, unless otherwise specified, the raw materials or reagents required for preparation are all commercially available products well known to those skilled in the art.

[0026] This invention provides a high-purity phosphor with the chemical composition Ca. 3-x-y Mg x Al2O6:yEu 2+ Where x and y represent mole fractions, 0 ≤ x ≤ 0.5, 0 <y≤0.02。

[0027] Preferably, x = 0.1~0.4, more preferably x = 0.2~0.3; y = 0.005~0.018, more preferably y = 0.01~0.015.

[0028] In the present invention, the particle size of the high color purity phosphor is preferably 3 - 20 μm.

[0029] The present invention provides a method for preparing the high color purity phosphor described in the above technical solution, comprising the following steps: According to the stoichiometric ratio of each element required in Ca 3-x-y Mg x Al2O6: yEu 2+ mix all the required raw materials and grind them to obtain a mixed material; when x = 0, the raw materials are a calcium source, an aluminum source, and an europium source, and when 0 < x ≤ 0.5, the raw materials are a calcium source, a magnesium source, an aluminum source, and an europium source; Calcine the mixed material in a reducing atmosphere, and then grind it to obtain the high color purity phosphor.

[0030] In the present invention, the calcium source preferably includes calcium carbonate, calcium oxide, or calcium nitrate, the calcium carbonate is preferably CaCO₃, and the calcium nitrate is preferably calcium nitrate.

[0031] In the present invention, the magnesium source preferably includes magnesium carbonate, magnesium oxide, or magnesium nitrate, more preferably MgO; the magnesium carbonate is preferably magnesium carbonate, and the magnesium nitrate is preferably magnesium nitrate.

[0032] In the present invention, the aluminum source preferably includes aluminum, aluminum oxide, or aluminum nitrate, more preferably Al₂O₃; the aluminum nitrate is preferably aluminum nitrate.

[0033] In the present invention, the europium source preferably includes europium oxide or europium carbonate, more preferably Eu₂O₃, and the europium carbonate is preferably europium carbonate.

[0034] In the present invention, the reducing atmosphere is preferably provided by a first gas, a second gas, or carbon powder; the first gas is preferably CO; the second gas is preferably a mixed gas composed of 10% hydrogen and 90% nitrogen by volume percentage.

[0035] In the present invention, the calcination temperature is preferably 1300 - 1400 °C, more preferably 1350 - 1400 °C.

[0036] In the present invention, when x = 0, the calcination time is 2 to 4 h, more preferably 3 h, or the calcination time is 8 to 12 h, more preferably 12 h; when the calcination time is 2 to 4 h, the high color purity phosphor is a blue phosphor, and when the excitation peak of the blue phosphor is 240 to 400 nm, the emission peak is 380 to 550 nm; when the calcination time is 8 to 12 h, the high color purity phosphor is a red phosphor, and when the excitation peak of the red phosphor is 240 to 630 nm, the emission peak is 550 to 800 nm.

[0037] In the present invention, when 0 < x ≤ 0.5, the calcination time is 8 to 12 h, the high color purity phosphor is a red phosphor, and when the excitation peak of the red phosphor is 240 to 630 nm, the emission peak is 550 to 800 nm.

[0038] After the calcination, it is preferably cooled to room temperature in the furnace, and the obtained calcined product is ground to the micron level to obtain a high color purity phosphor. The present invention has no special limitation on the mixing and grinding, and it can be carried out according to the processes well-known in the art.

[0039] The present invention provides an application of the high color purity phosphor described in the above technical solution or the high color purity phosphor prepared by the preparation method described in the above technical solution in a phosphor-converted white light-emitting diode (in the lighting field) or an LED display (in the display field), where x = 0 in the high color purity phosphor.

[0040] When x = 0, the prepared blue phosphor is excited by near ultraviolet light and is used for white light LED lamps; the red phosphor is excited by blue light and is used for white light LED lamps (in the lighting field, such as table lamps and street lamps) or LED displays (in the display field, such as monitors and televisions).

[0041] The present invention provides an application of the high color purity phosphor described in the above technical solution or the high color purity phosphor prepared by the preparation method provided in the above technical solution in laser display, where 0 < x ≤ 0.5 in the high color purity phosphor.

[0042] The following describes the specific embodiments of the present invention in detail, but it should be understood that the protection scope of the present invention is not limited by the specific embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the protection scope of the present invention.

[0043] In the experimental methods described in the embodiments of the present invention, unless otherwise specified, they are all conventional methods; the following reagents and raw materials, unless otherwise specified, are all commercially available.

[0044] Example 1

[0045] According to the chemical formula Ca 2.99 Al2O6: 0.01Eu 2+ To determine the stoichiometric ratio of each element, 0.598 g of CaCO3 (≥99%, AR), 0.2039 g of Al2O3 (≥99%, AR), and 0.00352 g of Eu2O3 (≥99%, AR) were weighed and mixed and ground for 30 min to obtain a mixed powder. The mixed powder was then calcined in a tube furnace at 1400℃ under a reducing atmosphere (90% N2 + 10% H2, volume fraction) for 3 h, and cooled to room temperature with the furnace to obtain the calcined product. The calcined product was ground to 3~20 μm to obtain the blue fluorescent powder Ca. 2.99 Al2O6: 0.01Eu 2+ .

[0046] Example 2

[0047] According to the chemical formula Ca 2.99 Al2O6: 0.01Eu 2+ The stoichiometric ratios of each element were determined by weighing 0.598 g of CaCO3 (≥99%, AR), 0.2039 g of Al2O3 (≥99%, AR), and 0.00352 g of Eu2O3 (≥99%, AR), respectively, and grinding them together for 30 min to obtain a mixed powder. This mixed powder was then calcined in a tube furnace at 1400℃ under a reducing atmosphere (90% N2 + 10% H2, volume fraction) for 12 h, and cooled to room temperature with the furnace to obtain the calcined product. The calcined product was then ground to 3–20 μm to obtain the red fluorescent powder Ca. 2.99 Al2O6: 0.01Eu 2+ .

[0048] Example 3

[0049] According to the chemical formula Ca 2.89 Mg 0.1 Al2O6: 0.01Eu 2+ The stoichiometric ratios of each element were determined by weighing 0.578 g of CaCO3 (≥99%, AR), 0.0081 g of MgO (≥99%, AR), 0.2039 g of Al2O3 (≥99%, AR), and 0.00352 g of Eu2O3 (≥99%, AR), respectively, and grinding them together for 30 min to obtain a mixed powder. This mixed powder was then calcined in a tube furnace at 1400℃ under a reducing atmosphere (90% N2 + 10% H2, volume fraction) for 12 h, and cooled to room temperature with the furnace to obtain the calcined product. The calcined product was then ground to 3–20 μm to obtain the red fluorescent powder Ca. 2.89 Mg 0.1 Al2O6: 0.01Eu 2+.

[0050] Example 4

[0051] According to the chemical formula Ca 2.59 Mg 0.4 Al2O6: 0.01Eu 2+ The stoichiometric ratios of each element were determined by weighing 0.518 g of CaCO3 (≥99%, AR), 0.0322 g of MgO (≥99%, AR), 0.2039 g of Al2O3 (≥99%, AR), and 0.00352 g of Eu2O3 (≥99%, AR), respectively, and grinding them together for 30 min to obtain a mixed powder. This mixed powder was then calcined in a tube furnace at 1400℃ under a reducing atmosphere (90% N2 + 10% H2, volume fraction) for 12 h, and cooled to room temperature with the furnace to obtain the calcined product. The calcined product was then ground to 3–20 μm to obtain the red fluorescent powder Ca. 2.59 Mg 0.4 Al2O6: 0.01Eu 2+ .

[0052] Example 5

[0053] According to the chemical formula Ca 2.58 Mg 0.4 Al2O6: 0.02Eu 2+ The stoichiometric ratios of each element were determined by weighing 0.516 g of CaCO3 (≥99%, AR), 0.0322 g of MgO (≥99%, AR), 0.2039 g of Al2O3 (≥99%, AR), and 0.00704 g of Eu2O3 (≥99%, AR), respectively, and grinding them together for 30 min to obtain a mixed powder. This mixed powder was then calcined in a tube furnace at 1400℃ under a reducing atmosphere (90% N2 + 10% H2, volume fraction) for 12 h, and cooled to room temperature with the furnace to obtain the calcined product. The calcined product was then ground to 3–20 μm to obtain the red fluorescent powder Ca. 2.59 Mg 0.4 Al2O6:0.02Eu 2+ .

[0054] Characterization and performance testing

[0055] 1) The XRD pattern of the blue phosphor prepared in Example 1 is shown below. Figure 1 As shown; the XRD pattern of the red phosphor prepared in Example 2 is shown. Figure 4 As shown. By Figure 1 and Figure 4 It can be seen that the XRD diffraction peak positions of the luminescent materials prepared in Examples 1 and 2 are in good agreement with the refinement results, and are good single-phase samples.

[0056] 2)The luminescent materials prepared in Example 1 and Example 2 were subjected to excitation and emission tests, and the spectrograms are respectively as Figure 2 and Figure 5 shown.

[0057] It can be seen from Figure 2 that the excitation peak range of the blue phosphor prepared in Example 1 is 240 - 400 nm, and the strongest excitation peak is located at 320 - 360 nm, which can effectively absorb the excitation in the near-ultraviolet light range and match the near-ultraviolet chip, greatly improving the light conversion efficiency. The emission peak range of the blue phosphor prepared in Example 1 is 380 - 550 nm, and the strongest emission peak is located at 443 nm, which is suitable for high-brightness white LEDs.

[0058] It can be seen from Figure 5 that the excitation peak range of the red phosphor prepared in Example 2 is 240 - 630 nm, and the strongest excitation peak is located at 440 - 470 nm. The broad excitation spectrum completely covers the usage range of blue chips, making it applicable to LED lighting and display devices. The emission peak range of the red phosphor prepared in Example 2 is 550 - 800 nm, and the strongest emission peak is located in the red light region at 650 nm, which is suitable for white LED lighting and LED display, and can effectively improve the color rendering index and expand the color gamut.

[0059] 3)The CIE chromaticity coordinate analysis was respectively carried out on the phosphors prepared in Example 1 and Example 2, and the CIE chromaticity coordinate diagrams are respectively as Figure 3 and 6 shown. It can be seen from Figure 3 that the CIE chromaticity coordinate of the blue phosphor prepared in Example 1 is (0.16, 0.0565), showing a narrow-band blue light with high color purity. It can be seen from Figure 6 that the CIE chromaticity coordinate of the red phosphor prepared in Example 2 is (0.6879, 0.3093), showing a narrow-band red light with high color purity.

[0060] 4) Figure 7 is the emission spectrum of the blue phosphor prepared in Example 1 with the excitation light wavelength of 334 nm changing with the sintering time; it can be seen from Figure 7 that as the sintering time of the blue phosphor prepared in Example 1 increases from 3 to 12 h, its emission spectrum in the range of 380 - 550 nm gradually decreases until it completely disappears.

[0061] Figure 8 is the emission spectrum of the red phosphor prepared in Example 2 with the excitation light wavelength of 460 nm changing with the sintering time. It can be seen from Figure 8 that as the sintering time of the red phosphor prepared in Example 2 increases from 3 to 12 h, its emission spectrum in the range of 550 - 800 nm gradually increases.

[0062] 5) The emission spectra of the red phosphors prepared in Examples 3-5 are as follows: Figure 9 As shown. By Figure 9 It can be seen that the XRD diffraction peak positions of the phosphors prepared in Examples 3-5 match well with those of the standard cards, indicating that they are good single-phase samples.

[0063] 6) The emission spectra of the red phosphors prepared in Examples 3-5 and Example 2 are shown below. Figure 10 As shown. By Figure 10 It can be seen that the sample exhibits bright red emission under 460nm blue light excitation, with an emission spectrum ranging from 550-800nm ​​and an optimal emission peak at 650-652nm. This was confirmed by Mg... 2+ The doping of Mg significantly improved the emission intensity of the sample, which is due to the doping of Mg. 2+ The lattice chemical strain caused by doping helps to improve the reduction of Eu.

[0064] 7) CIE chromaticity coordinate analysis was performed on the red phosphors prepared in Examples 4-5 and Example 2, respectively. The CIE chromaticity coordinate diagrams are shown below. Figure 11 As shown. The CIE chromaticity coordinates of the red phosphors prepared in Examples 4-5 and Example 2 are as follows: Example 2 (0.6879, 0.3093), Example 4 (0.6919, 0.3088), and Example 5 (0.7002, 0.2997), respectively. (The text abruptly ends here, likely due to an incomplete translation or missing information.) 2+ With the addition of doping, the chromaticity value of the sample was improved, with CIEx increasing from 0.69 to 0.70, making CIEx > 0.7 indicate high color purity. Higher CIEx values ​​indicate higher phosphor purity, providing a more vibrant display.

[0065] 8) The red phosphor prepared in Example 4 was excited by blue light at 460 nm and cooled from room temperature to 230 °C. o Emission spectrum testing was performed within range C, such as Figure 12 As shown, the luminescence intensity of the sample gradually decreases with increasing temperature, reaching a minimum at 155°C. o At temperature C, the luminescence intensity of the sample reached 57.9% of the luminescence intensity at room temperature.

[0066] 9) The red phosphor prepared in Example 2, under 460 nm blue light excitation, reacted at room temperature to 230 °C. o Emission spectrum testing was performed within range C, such as Figure 13 As shown, the luminescence intensity of the sample gradually decreases with increasing temperature, reaching a minimum at 155°C. o At temperature C, the luminescence intensity of the sample reached 23.4% of the luminescence intensity at room temperature. It had low thermal stability and could not withstand high-energy irradiation by blue laser, so it could not be used for laser display at all.

[0067] 10) The red phosphors prepared in Examples 4 and 2 were excited by blue light at 460 nm and the temperature was increased from room temperature to 230 °C. o Compare the luminous intensity within the C range, such as Figure 14 As shown. At 155 o At temperature C, the luminescence intensity of Example 4 was 2.47 times that of Example 2. Mg 2+ The doping significantly improves the thermal stability of the sample, enabling the material to operate at higher temperatures, better withstand the energy impact of blue laser excitation, and is more suitable for laser display applications. This significant improvement in thermal stability is mainly due to Mg. 2+ After doping, the trap depth of electron traps in the crystal lattice decreases. Electrons trapped in shallower electron traps escape more easily during thermal activation. The escaped electrons return to the Eu crystal. 2+ The emission reaches the 5d energy level and then returns to the ground state. This partial emission effectively compensates for the loss of luminescence intensity under thermal quenching, improving the thermal stability of the sample by 2.47 times.

[0068] 11) The irradiation energy of the red phosphor prepared in Example 5 under blue laser excitation was tested, such as... Figure 15 As shown, the phosphor in Example 5 exhibits a high luminescence saturation threshold under blue laser excitation.

[0069] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A high-purity phosphor, characterized in that, The chemical composition is Ca 3-x-y Mg x Al2O6: yEu 2+ Where x and y represent mole fractions, 0 ≤ x ≤ 0.5, 0 <y≤0.02。 2. The high-purity phosphor according to claim 1, characterized in that, x = 0.1 to 0.4, y = 0.005 to 0.

018.

3. The high-purity phosphor according to claim 2, characterized in that, x = 0.2 to 0.3, y = 0.01 to 0.

015.

4. The method for preparing the high-purity phosphor according to any one of claims 1 to 3, characterized in that, It includes the following steps: According to Ca 3-x-y Mg x Al2O6: yEu 2+ Mix and grind the required raw materials according to the stoichiometric ratios of the elements required in Al2O6: yEu. When x = 0, the raw materials are a calcium source, an aluminum source, and an europium source. When 0 < x ≤ 0.5, the raw materials are a calcium source, a magnesium source, an aluminum source, and an europium source; In a reducing atmosphere, the mixture is calcined and then ground to obtain a high color purity phosphor.

5. The preparation method according to claim 4, characterized in that, The calcium source includes calcium carbonate, calcium oxide or calcium nitrate; The magnesium source includes magnesium carbonate, magnesium oxide or magnesium nitrate; The aluminum source includes aluminum, aluminum oxide or aluminum nitrate; The europium source includes europium oxide or europium carbonate.

6. The preparation method according to claim 5, characterized in that, The reducing atmosphere is provided by a first gas, a second gas or carbon powder; the first gas is CO; the second gas is a mixed gas composed of 10% hydrogen and 90% nitrogen by volume percentage; The calcination temperature is 1300 to 1400 °C.

7. According to the preparation method described in claim 6, characterized in that When x = 0, the calcination time is 2 to 4 h, or the calcination time is 8 to 12 h; When the calcination time is 2 to 4 h, the high color purity phosphor is a blue phosphor; when the excitation peak of this blue phosphor is 240 to 400 nm, the emission peak is 380 to 550 nm; 8. The preparation method according to claim 6, characterized in that, When the calcination time is 8 to 12 h, the high color purity phosphor is a red phosphor; when the excitation peak of this red phosphor is 240 to 630 nm, the emission peak is 550 to 800 nm.

9. The application of the high-purity phosphor according to any one of claims 1 to 3 or the high-purity phosphor prepared by the preparation method according to claims 4 to 7 in phosphor-converting white light diodes or LED displays, characterized in that, When 0 < x ≤ 0.5, the calcination time is 8 to 12 h, and the high color purity phosphor is a red phosphor; when the excitation peak of this red phosphor is 240 to 630 nm, the emission peak is 550 to 800 nm.

10. The application of the high-purity phosphor according to any one of claims 1 to 3 or the high-purity phosphor prepared by the preparation method according to claims 4 to 6 and 8 in laser displays, characterized in that, x = 0 in the high color purity phosphor. 0 < x ≤ 0.5 in the high color purity phosphor.

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