A blue-cyan aluminate phosphor and its composite fluorescent glass

Abstract

The present invention relates to a blue-cyan aluminate fluorescent powder and a composite fluorescent glass thereof. The fluorescent powder has the following general formula: x B y Eu k Al h C g O 34+δ ;Wherein A is one or more of Na, K, Rb, and Cs;B is one or more of Ba, Sr, Ca, and Mg;C is one or more of Ga, B, and In;X, y, k, h, g, and δ are molar coefficients, and 0≤x≤2.6, 0≤y≤2.6, 0≤k≤0.6, 0≤h≤22, and 0≤g≤22, and δ changes in value according to the law of electroneutrality. After the phosphor is evenly mixed with the mesoporous silicon oxide molecular sieve, it is placed in a discharge plasma sintering furnace and sintered to obtain a fluorescent glass. The phosphor and fluorescent glass of the present invention can be effectively excited by (near) ultraviolet light (360-420nm), and are suitable as blue and cyan fluorescent materials for full-spectrum illumination excited by near-ultraviolet light.

Description

Technical Field

[0001] The invention belongs to the field of fluorescent materials, and in particular relates to a blue-cyan aluminate fluorescent powder and a composite fluorescent glass thereof. Background Art

[0002] White light emitting diodes (WLEDs) are a new type of solid-state light source. Compared with traditional incandescent tungsten filament bulbs and fluorescent lamps, they have the advantages of small size, long life, fast response speed, and green environmental protection. White light LEDs can be flat-packed and easily developed into thin and portable products. They have gradually replaced traditional lighting sources and are known as the fourth generation of lighting sources. As a composite light, white light can be obtained from the three primary colors of red, green, and blue or from a combination of other colors. At present, the main ways to obtain white light are: a combination of three primary color LED chips, a blue light LED chip combined with Y3Al5O 12 :Ce 3+ (YAG) yellow phosphor and near-ultraviolet LED chips combined with red, green, and blue phosphors. The three-color LED chip combination suffers from complex control circuitry, high packaging requirements, and a tendency to color shift over time, making it unsuitable for indoor lighting. Blue LED chips combined with YAG yellow phosphor are currently the mainstream commercial white light solution. This combination offers advantages such as high light conversion efficiency, good thermal stability, and simple packaging. However, due to the lack of a red component, this combination results in a high color temperature and a low color rendering index. Long-term use can affect sleep and various physiological activities, making it difficult to meet the requirements of indoor lighting or wide color gamut displays. In contrast, near-ultraviolet LED chips combined with red, green, and blue phosphors can produce white light with excellent color rendering and adjustable color temperature, effectively solving the blue light spillover problem associated with blue LED chips combined with YAG yellow phosphors. This makes it suitable for indoor lighting and lighting environments requiring high color reproduction, leading to an increasing research interest in these technologies in recent years. Among various phosphor systems, the lack of luminescence in the cyan region (480-520nm) is becoming increasingly apparent. In white solid-state lighting, the absence of cyan light often reduces white light uniformity, hindering the improvement of color rendering index. This phenomenon is commonly known as the cyan gap. Therefore, in order to obtain full-spectrum white light LEDs that approach the solar spectrum, it is crucial to develop near-ultraviolet excited cyan fluorescent materials.

[0003] Currently, traditional LED lighting primarily uses a cured mixture of phosphor and silicone / epoxy resin as the light conversion material. While this process has been industrialized, it suffers from a low luminescence threshold at high power. Long-term exposure to heat and light radiation can severely degrade the silicone / epoxy resin, impacting product performance. To address this issue, phosphors are often encapsulated in a glass or ceramic matrix for improved physical and chemical stability. Glass matrices offer advantages such as high transmittance, simple preparation, and adjustable composition, making composite phosphor glass a research hotspot for solid-state lighting light conversion materials. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a blue-cyan aluminate phosphor and a composite fluorescent glass thereof. The phosphor and the fluorescent glass can be effectively excited by (near) ultraviolet light (360-420nm) and are suitable as blue and cyan fluorescent materials for full-spectrum lighting excited by near-ultraviolet light.

[0005] The present invention provides a blue-cyan aluminate phosphor, which has the following general formula: x B y Eu k Al h C g O 34+δ ; Wherein A is one or more of Na, K, Rb, Cs; B is one or more of Ba, Sr, Ca, Mg; C is one or more of Ga, B, In; x, y, k, h, g, δ are molar coefficients, 0≤x≤2.6, 0≤y≤2.6, 0≤k≤0.6, 0≤h≤22, 0≤g≤22, δ changes according to the law of electrical neutrality.

[0006] Furthermore, the phosphor emits bluish-cyan light with a peak wavelength of 450 nm to 500 nm.

[0007] The present invention also provides a method for preparing a blue-cyan aluminate phosphor, comprising the following steps:

[0008] (1) Weigh the reactant raw materials in the corresponding proportion according to the stoichiometric ratio;

[0009] (2) Grinding the above reactant raw materials uniformly to obtain a mixed powder, and transferring the mixed powder into a crucible;

[0010] (3) The crucible is placed in a horizontal tube furnace and kept at 1300-1400° C. for 4-6 hours under a reducing atmosphere. After the reaction is completed, the crucible is crushed and ground to obtain a blue-cyan aluminate phosphor.

[0011] Furthermore, the reducing atmosphere in step (3) is composed of 10%-20% H2 and 80%-90% N2 by volume.

[0012] The present invention also provides a blue-cyan aluminate composite fluorescent glass, which is obtained by mixing and sintering the blue-cyan aluminate fluorescent powder and the mesoporous silicon oxide molecular sieve.

[0013] Furthermore, the mesoporous silica molecular sieve is one or more of FDU-12, SBA-15, MCM-41, MSN and ZSM-5.

[0014] Furthermore, the composite fluorescent glass emits blue light with a peak wavelength of 443 nm.

[0015] The present invention also provides a method for preparing blue-cyan aluminate composite fluorescent glass, comprising the following steps:

[0016] (1) Grinding the blue-cyan aluminate phosphor and the mesoporous silica molecular sieve to obtain a mixed powder, and then placing the powder into a mold;

[0017] (2) placing the mold in a spark plasma sintering furnace for sintering, wherein the sintering process parameters are: sintering temperature of 910-1000°C, heating rate of 100-600°C / min, pressure of 50-60 MPa, holding time of 1-3 min, and vacuum sintering; (3) double-sided grinding and polishing the fluorescent glass block obtained in step (2) to obtain blue-cyan aluminate composite fluorescent glass.

[0018] Furthermore, the mass ratio of the blue-cyan aluminate phosphor to the mesoporous silica molecular sieve is 0.01-0.25:1.

[0019] Furthermore, the blue-cyan aluminate phosphor or the blue-cyan aluminate composite fluorescent glass is effectively excited by near-ultraviolet light of 360-420 nm.

[0020] The present invention also provides the use of blue-cyan aluminate fluorescent powder or blue-cyan aluminate composite fluorescent glass in full-spectrum lighting excited by near-ultraviolet light.

[0021] Beneficial effects

[0022] The phosphor and composite fluorescent glass provided by the present invention can be effectively excited by (near) ultraviolet light of 360-420nm. Among them, the aluminate phosphor can emit blue-cyan light with a peak wavelength of 450-500nm; at room temperature, its fluorescence quantum efficiency can reach up to 98.26%; at 150°C, its luminous intensity can be maintained at a maximum of 86.90% of that at room temperature. Compared with existing near-ultraviolet excited cyan fluorescent materials, it has the advantages of high quantum efficiency and good resistance to thermal quenching; the composite fluorescent glass can emit blue light with a peak wavelength of 443nm; at room temperature, its fluorescence quantum efficiency is 79.51%; at 150°C, its luminous intensity can be maintained at a maximum of 105.6% of that at room temperature, showing anti-thermal quenching performance. After the above-mentioned phosphor is compounded with mesoporous silica molecular sieve, its thermal stability is significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 K prepared in Example 1 1.8 Eu 0.4 Al 17.83 GaO 33.9 X-ray diffraction spectrum of phosphor;

[0024] Figure 2 K prepared in Example 1 1.8 Eu 0.4 Al 17.83 GaO 33.9 Excitation spectrum (a), emission spectrum (b), fluorescence quantum efficiency diagram (c), and temperature-dependent fluorescence spectrum (d) of the phosphor;

[0025] Figure 3 K prepared in Example 2 1.4 Ba 0.4 Eu 0.4 Al 17.83 GaO 33.9 X-ray diffraction spectrum of phosphor;

[0026] Figure 4 K prepared in Example 2 1.4 Ba 0.4 Eu 0.4 Al 17.83 GaO 33.9 Excitation spectrum (a), emission spectrum (b), fluorescence quantum efficiency diagram (c), and temperature-dependent fluorescence spectrum (d) of the phosphor;

[0027] Figure 5 K prepared in Example 3 1.0 Ba 0.8 Eu 0.4 Al 17.83 GaO 33.9 X-ray diffraction spectrum of phosphor;

[0028] Figure 6 K prepared in Example 3 1.0 Ba 0.8 Eu 0.4 Al 17.83 GaO 33.9 Excitation spectrum (a), emission spectrum (b), fluorescence quantum efficiency diagram (c), and temperature-dependent fluorescence spectrum (d) of the phosphor;

[0029] Figure 7 K prepared in Example 4 1.8 Eu 0.4 Al 17.83 GaO 33.9 X-ray diffraction spectrum of composite fluorescent glass;

[0030] Figure 8 K prepared in Example 4 1.8 Eu 0.4 Al 17.83 GaO 33.9 Excitation spectrum (a), emission spectrum (b), fluorescence quantum efficiency diagram (c), and temperature-dependent fluorescence spectrum (d) of the composite fluorescent glass;

[0031] Figure 9 K prepared in Comparative Example 1 1.8 Eu 0.4 Al 21.83 O 33.9 X-ray diffraction spectrum of phosphor;

[0032] Figure 10 K prepared in Comparative Example 1 1.8 Eu 0.4 Al 21.83 O 33.9 Excitation spectrum (a), emission spectrum (b), fluorescence quantum efficiency diagram (c), and temperature-dependent fluorescence spectrum (d) of the phosphor;

[0033] Figure 11 This is a performance diagram of the blue-cyan aluminate phosphor of the present invention. DETAILED DESCRIPTION

[0034] Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiments are only used to illustrate the present invention and are not used in limiting the scope of the present invention.In addition, should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall equally within the scope limited by the appended claims of the application.

[0035] In the following examples and comparative examples, the instruments used for testing the relevant properties of the prepared samples are:

[0036] 1. The crystal structure and phase analysis of the samples were performed using a Japanese Rigaku D / max-2500 X-ray diffractometer, with the radiation source being a Cu target Ka1 radiation.

[0037] 2. The excitation spectrum and emission spectrum of the sample were tested using the F-4600 fluorescence spectrometer produced by Hitachi, Japan;

[0038] 3. The temperature-varying spectra of the samples were tested using the FLS1000 fluorescence spectrometer from Edinburgh, UK;

[0039] 4. The internal quantum efficiency of the sample was tested by a Hamamatsu Quantaurus-QY plus fluorescence spectrometer equipped with an integrating sphere.

[0040] Example 1

[0041] Weigh K2CO3 (0.157 g), Al(OH)3 (1.000 g), Ga2O3 (0.267 g), Eu2O3 (0.050 g), and H3BO3 (0.074 g), mix the above raw materials and grind them to mix evenly. Then put the mixed powder into an alumina crucible, and then put it into a horizontal tube furnace with a reducing atmosphere (composed of 10% H2 and 90% N2 by volume. The components and content of the reducing atmosphere in the following embodiments are the same as those in this embodiment). Heat to 1300°C at a heating rate of 5°C / min, keep warm for 4 hours, and cool naturally to below 200°C in the furnace. Take out and grind the obtained product thoroughly to obtain sample S1.

[0042] The prepared sample S1 was subjected to crystal structure and phase analysis. Figure 1 As shown by Figure 1 It can be seen that the main crystalline phase of sample S1 prepared in this embodiment is K 1.8 Eu 0.4 Al 17.83 GaO 33.9 , no mixed phases were seen.

[0043] The prepared sample S1 was tested for fluorescence performance, and the test results were as follows: Figure 2 As shown. Figure 2 (a) It can be seen that the sample S1 prepared in this embodiment can be effectively excited by (near) ultraviolet light of about 360-420nm; Figure 2 (b) It can be seen that the sample S1 prepared in this embodiment can emit blue light with a peak wavelength of 450nm after being excited by 400nm near-ultraviolet light; Figure 2 (c) It can be seen that the fluorescence quantum yield of sample S1 prepared in this embodiment is 98.26% under 400nm near-ultraviolet light excitation at 25°C; Figure 2(d) It can be seen that the sample S1 prepared in this embodiment has excellent resistance to thermal quenching. At 150°C, its fluorescence intensity can be maintained at 84.84% of that at room temperature.

[0044] Example 2

[0045] Weigh K2CO3 (0.138 g), Ba2CO3 (0.056 g), Al(OH)3 (1.000 g), Ga2O3 (0.267 g), Eu2O3 (0.050 g), and H3BO3 (0.075 g), mix the above raw materials and grind them to make the raw materials mixed evenly, then put the mixed powder into an alumina crucible, and then put it into a horizontal tube furnace with a reducing atmosphere, heat it to 1300°C at a heating rate of 5°C / min, keep it warm for 4 hours, cool it naturally to below 200°C in the furnace, take it out, and grind the product thoroughly to obtain sample S2.

[0046] The prepared sample S2 was subjected to crystal structure and phase analysis. Figure 3 As shown by Figure 3 It can be seen that the main crystalline phase of sample S2 prepared in this embodiment is K 1.4 Ba 0.4 Eu 0.4 Al 17.83 GaO 33.9 , no obvious impurities were found.

[0047] The prepared sample S2 was tested for fluorescence performance, and the test results were as follows: Figure 4 As shown. Figure 4 (a) It can be seen that the sample S2 prepared in this embodiment can be effectively excited by (near) ultraviolet light of 360-420nm; Figure 4 (b) It can be seen that the sample S2 prepared in this embodiment can emit cyan light with a peak wavelength of 476nm after being excited by 400nm near-ultraviolet light; Figure 4 (c) It can be seen that the fluorescence quantum yield of sample S2 prepared in this embodiment is 97.97% under 400nm near-ultraviolet light excitation at 25°C; Figure 4 (d) It can be seen that the sample S2 prepared in this embodiment has excellent resistance to thermal quenching. At 150°C, its fluorescence intensity can be maintained at 85.20% of that at room temperature.

[0048] Example 3

[0049] Weigh K2CO3 (0.118 g), Ba2CO3 (0.112 g), Al(OH)3 (1.000 g), Ga2O3 (0.267 g), Eu2O3 (0.050 g), and H3BO3 (0.075 g), mix the above raw materials and grind them to make the raw materials mixed evenly, then put the mixed powder into an alumina crucible, and then put it into a horizontal tube furnace with a reducing atmosphere, heat it to 1300°C at a heating rate of 5°C / min, keep it warm for 4 hours, cool it naturally to below 200°C in the furnace, take it out, and grind the product thoroughly to obtain sample S3.

[0050] The prepared sample S3 was subjected to crystal structure and phase analysis. Figure 5 As shown by Figure 5 It can be seen that the main crystalline phase of sample S3 prepared in this embodiment is K 1.0 Ba 0.8 Eu 0.4 Al 17.83 GaO 33.9 , no obvious impurities were found.

[0051] The prepared sample S3 was tested for fluorescence performance, and the test results were as follows: Figure 6 As shown. Figure 6 (a) It can be seen that the sample S3 prepared in this embodiment can be effectively excited by (near) ultraviolet light of 360-420nm; Figure 6 (b) It can be seen that the sample S3 prepared in this embodiment can emit cyan light with a peak wavelength of 500nm after being excited by 400nm near-ultraviolet light; Figure 6 (c) It can be seen that the fluorescence quantum yield of sample S3 prepared in this embodiment is 84.43% under 400nm near-ultraviolet light excitation at 25°C; Figure 6 (d) It can be seen that the sample S3 prepared in this embodiment has excellent resistance to thermal quenching. At 150°C, its fluorescence intensity can be maintained at 86.90% of that at room temperature.

[0052] Example 4

[0053] A mixture of blue aluminate phosphor and mesoporous silica molecular sieve at a mass ratio of 0.1:10 was placed in a graphite mold and sintered in a spark plasma sintering (SPS) apparatus. SPS was performed under vacuum conditions at a pressure of 50 MPa. The heating rate during sintering was 100-600°C / min, the sintering temperature was 910-1000°C, and the holding time was 1 minute. After sintering, the instrument was turned off and the sample was allowed to cool to room temperature. After removal and grinding and polishing, the composite fluorescent glass S4 was obtained.

[0054] The prepared composite fluorescent glass was subjected to crystal structure and phase analysis. Figure 7 As shown by Figure 7 It can be seen that the composite fluorescent glass is composed of amorphous phase and K 1.8 Eu 0.4 Al 17.83 GaO 33.9 Phase composition. XRD results show that K 1.8 Eu 0.4 Al 17.83 GaO 33.9 The phase remains stable after high-temperature sintering.

[0055] The prepared composite fluorescent glass was tested for fluorescence performance, and the test results were as follows: Figure 8 As shown. Figure 8 (a) It can be seen that the composite fluorescent glass prepared in this embodiment can be effectively excited by 360-380nm (near) ultraviolet light; Figure 8 (b) It can be seen that the composite fluorescent glass prepared in this embodiment can emit blue light with a peak wavelength of 443 nm after being excited by 360 nm ultraviolet light; Figure 8 (c) It can be seen that the fluorescence quantum yield of sample S4 prepared in this embodiment is 79.51% under 360nm ultraviolet light excitation at 25°C; Figure 8 (d) It can be seen that the composite fluorescent glass prepared in this embodiment has anti-thermal quenching performance. At 150° C., its fluorescence intensity can be maintained at 105.6% of that at room temperature, and its thermal stability is significantly improved.

[0056] Comparative Example 1

[0057] Weigh K2CO3 (0.129 g), Al(OH)3 (1.000 g), Eu2O3 (0.041 g), and H3BO3 (0.058 g), mix the above raw materials evenly and grind them to make the raw materials evenly mixed. Then put the mixed powder into an alumina crucible, and then put it into a horizontal tube furnace with a reducing atmosphere. Heat it to 1300°C at a heating rate of 5°C / min, keep it warm for 4 hours, and cool it naturally to below 200°C in the furnace. Take it out and grind the obtained product thoroughly to obtain comparison sample S5.

[0058] The prepared comparative sample S5 was subjected to crystal structure and phase analysis. Figure 9 As shown by Figure 9 It can be seen that the main crystalline phase of sample S5 prepared in this comparative example is K 1.8 Eu 0.4 Al 21.83 O 33.9 , accompanied by a small amount of Al2O3 impurity phase.

[0059] The prepared comparative sample S5 was tested for fluorescence performance, and the test results were as follows: Figure 10 As shown. Figure 10 (a) It can be seen that the absorption of the comparative sample S5 prepared in this comparative example at 400nm is weaker than that of the samples S1-S3, and the optimal excitation is located at 360nm, indicating that the component regulation of the present invention can significantly improve the absorption of the aluminate phosphor in the near-ultraviolet band. Figure 10 (b) It can be seen that the comparative sample S5 prepared in this comparative example can emit blue light with a peak wavelength of 450nm after being excited by 400nm near-ultraviolet light; Figure 10 (c) It can be seen that the fluorescence quantum yield of the comparative sample S5 prepared in this comparative example is 74.29% under 400nm near-ultraviolet light excitation at 25°C, which is significantly lower than that of the samples S1-S3; Figure 10 (d) It can be seen that at 150° C., the fluorescence intensity of the comparative sample S5 is 81.80% of that at room temperature, which is lower than that of the samples S1-S4 in Examples 1-4.

[0060] In summary, the present invention significantly improves the absorption efficiency of aluminate phosphors in the near-ultraviolet region through component manipulation, while also enhancing their fluorescence quantum yield and thermal stability. Furthermore, by encapsulating the phosphors in a glass matrix, the thermal stability of the fluorescent material is effectively enhanced. The composite fluorescent glass even exhibits an anti-thermal quenching effect, demonstrating promising application prospects.

Claims

1. A blue-cyan aluminate phosphor, characterized by: The phosphor is: K 1.8 Eu 0.4 Al 17.83 GaO 33.9 , K 1.4 Ba 0.4 Eu 0.4 Al 17.83 GaO 33.9 , K 1.0 Ba 0.8 Eu 0.4 Al 17.83 GaO 33.9 or K 1.8 Eu 0.4 Al 17.83 GaO 33.9 .

2. The phosphor according to claim 1, wherein: The phosphor emits blue-cyan light with a peak wavelength of 450nm-500nm.

3. A method for preparing the blue-cyan aluminate phosphor according to any one of claims 1 to 2, comprising the following steps: (1) Weigh the reactant raw materials in the corresponding proportion according to the stoichiometric ratio; (2) Grinding the above reactant raw materials uniformly to obtain a mixed powder, and transferring the mixed powder into a crucible; (3) The crucible is placed in a horizontal tube furnace and kept at 1300-1400° C. for 4-6 hours under a reducing atmosphere. After the reaction is completed, the crucible is crushed and ground to obtain a blue-cyan aluminate phosphor.

4. The preparation method according to claim 3, wherein: The reducing atmosphere in step (3) is composed of 10%-20% H2 and 80%-90% N2 by volume.

5. A blue-cyan aluminate composite fluorescent glass, characterized by: The blue-cyan aluminate phosphor is obtained by mixing and sintering the blue-cyan aluminate phosphor as claimed in claim 1 and a mesoporous silicon oxide molecular sieve.

6. The composite fluorescent glass according to claim 5, characterized in that: The mesoporous silica molecular sieve is one or more of FDU-12, SBA-15, MCM-41, MSN and ZSM-5.

7. The composite fluorescent glass according to claim 5, characterized in that: The composite fluorescent glass emits blue light with a peak wavelength of 443 nm.

8. A method for preparing a blue-cyan aluminate composite fluorescent glass as described in any one of claims 5 to 7, comprising the following steps: (1) grinding blue-cyan aluminate phosphor and mesoporous silica molecular sieve uniformly to obtain a mixed powder, and loading the powder into a mold; (2) placing the mold in a spark plasma sintering furnace for sintering, wherein the sintering process parameters are: sintering temperature of 910-1000°C, heating rate of 100-600°C / min, pressure of 50-60MPa, holding time of 1-3min, and vacuum sintering; (3) double-sided grinding and polishing the fluorescent glass block obtained in step (2) to obtain the blue-cyan aluminate composite fluorescent glass.

9. The blue-cyan aluminate phosphor according to claim 1 or the blue-cyan aluminate composite fluorescent glass according to claim 5, characterized in that: Efficiently excited by near-ultraviolet light in the range of 360-420nm.

10. Use of the blue-cyan aluminate phosphor according to claim 1 or the blue-cyan aluminate composite fluorescent glass according to claim 5 in full-spectrum lighting excited by near-ultraviolet light.

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