Multicolor luminescent silicate fluorescent material and method for preparing the same

Abstract

The application belongs to the field of luminescent materials, and provides a multi-color luminescent silicate fluorescent material and a preparation method thereof. 2.99 Y 1‑m M m Si2O7:xEu (0 < x < 0.04, 0 < m < 0.2, M = La / Ba / Hf) fluorescent powder, the thermal stability of the material is improved by equivalent / heterovalent substitution of M ions on Y 3+ Ions, the luminescent intensity is improved, the luminescent color of a single matrix from green light to cyan light and white light is adjusted, a single matrix multi-color fluorescent material is obtained, and the application has application value in the field of WLEDs.

Description

Technical Field

[0001] This invention belongs to the field of luminescent materials, and specifically relates to a multicolor luminescent silicate fluorescent material and its preparation method. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] In recent years, white light-emitting diodes (WLEDs), as the fourth generation of light sources, have gradually replaced traditional light sources in the lighting and display fields due to their advantages such as small size, environmental friendliness, and energy efficiency. Currently, common WLEDs mainly consist of a blue InGaN chip coated with Y3Al5O4. 12 :Ce 3+ Yellow-emitting fluorescent materials are used. However, the emission spectrum of this type of WLED lacks red and cyan components, resulting in a low color rendering index (Ra<80) and a high color temperature (CCT>6000K). The excessively low Ra value is detrimental to the natural and accurate reproduction of the colors of illuminated objects. Furthermore, the emission spectrum of the blue InGaN chip highly overlaps with the melatonin suppression curve, leading to serious blue light hazards. Long-term exposure to blue-rich white light can cause health problems such as circadian rhythm disorders, insomnia, cataracts, and macular degeneration. One strategy for improving WLED devices is to combine blue, green, and red phosphors with a near-ultraviolet (NUV) chip to improve Ra and CCT, while also making it easier to achieve tunable emission colors and effectively reduce the aforementioned blue light hazards. However, the use of multiple phosphor types complicates the production process, and differences in reabsorption and thermal stability between phosphors lead to decreased efficiency. Simultaneously, the cyan spectrum (480-520nm) is still missing in the three-color WLED spectrum, making it difficult to obtain a WLED with a solar-like spectrum. Therefore, developing single-component fluorescent materials with tunable emission color, high quantum efficiency, and good thermal stability has become one of the urgent needs in the field of WLED.

[0004] Eu 2+ 4f of ions 7 →4f 6 5d 1 Symmetric transitions exhibit strong absorption and high luminescence efficiency in the ultraviolet-visible region. When Eu... 2+ When ions enter a matrix lattice, the 5d level electrons are easily influenced by the local environment, such as crystal field strength, electronegativity, and coordination number. Therefore, Eu can be adjusted through chemical substitution. 2+ The surrounding local environment has become a key strategy for exploring novel phosphors and optimizing luminescence performance. Literature has reported the use of Ba... 2+ Replace Sr2+ The cation substitution strategy of SrY2O4:Eu 2+ The spectral emission peak of the phosphor is greatly red-shifted from 620nm to 773nm. By using the chemical unit co-substitution strategy, the mixed anion group Ba3CaK(PO4) 3-x (BO3) x :0.02Eu 2+ The phosphor can realize the adjustable emission color from blue to white. However, the multi-color phosphor material with adjustable emission color from green to cyan and white has not been found. SUMMARY

[0005] To solve the above problems, the application provides a multi-color luminescent silicate phosphor and a preparation method thereof. The application uses high-temperature solid-phase reaction to prepare a series of Na 2.99 Y 1-m M m Si2O7:xEu (0 3+ The equivalent / heterovalent substitution of M ions to Y ions improves the thermal stability of the material, increases the luminescent intensity, realizes the adjustable emission color from green to cyan and white of the single matrix, and obtains the single matrix multi-color phosphor, which has application value in the field of WLED.

[0006] To achieve the above object, the application adopts the following technical scheme.

[0007] In a first aspect, the application provides a multi-color luminescent silicate phosphor, the chemical formula of the phosphor being Na 2.99 Y 1-m M m Si2O7:xEu, 0

[0008] In some embodiments, x=0.01, 0.05≤m≤0.15.

[0009] In some embodiments, x=0.01, 0.1≤m≤0.2.

[0010] In some embodiments, x=0.01, 0.05≤m≤0.2.

[0011] In some embodiments, the phosphor can absorb 300-500nm (near) ultraviolet light, the emission spectrum range covers 400-700nm, and the half-peak width is different according to different M ions.

[0012] A preparation method of a multi-color luminescent silicate phosphor, comprising:

[0013] The oxide or salt containing element Na, the oxide or salt containing element Y, the oxide or salt containing element M, the oxide or salt containing element Si, the oxide or salt containing element Eu, and the alcohol solvent are mixed uniformly, grinded, to obtain a mixed powder;

[0014] The mixed powder is sintered under a reducing atmosphere to obtain a multi-color luminescent silicate fluorescent material;

[0015] The M is La, Ba or Hf.

[0016] The preparation method of the multi-color luminescent silicate fluorescent material is a traditional high-temperature solid-phase method, which has the advantages of high crystallinity and easy mass production.

[0017] In some embodiments, the oxide or salt containing element Na is NaCO3.

[0018] In some embodiments, the oxide or salt containing element Y is Y2O3.

[0019] In some embodiments, the oxide or salt containing element M is selected from at least one of La2O3, BaCO3, HfO2.

[0020] In some embodiments, the oxide or salt containing element Si is SiO2.

[0021] In some embodiments, the oxide or salt containing element Eu is Eu2O3.

[0022] In some embodiments, the reducing atmosphere is a mixed gas of nitrogen and hydrogen.

[0023] In some embodiments, the sintering condition is 1200-1300℃, constant temperature for 8-10h.

[0024] More specifically, it includes:

[0025] 1) A series of luminescent materials of Na 2.99 Y 1-m M m Si2O7:xEu (0 < x ≤ 0.04, 0 ≤ m ≤ 0.2, M = La / Ba / Hf) are prepared by high-temperature solid-phase method. The preparation is as follows:

[0026] The luminescent materials of Na 2.99 Y 1-m M mThe atomic molar ratio of Si2O7:xEu (0 < x < 0.04, 0 < m < 0.2, M = La / Ba / Hf) is prepared by using oxides or corresponding salts containing elements Na, Y, La, Ba, Hf, Si and Eu as raw materials, such as NaCO3, Y2O3, La2O3, BaCO3, HfO2, SiO2 and Eu2O3. The weighed raw materials are mixed with a certain amount of anhydrous ethanol in a mortar and are ground thoroughly to obtain a mixed powder. The obtained mixed powder is loaded into an alumina crucible and heated to 1200 DEG C in a reducing atmosphere (90% N2 / 10% H2) for 8 hours. After cooling to room temperature, the fired sample is taken out and is ground uniformly.

[0027] In a third aspect of the present application, a WLED device is provided, comprising: a light source, and the fluorescent material as described above.

[0028] In a fourth aspect of the present application, a green silicate fluorescent material is provided, with a chemical formula of

[0029] Na 2.99 YSi2O7:xEu, wherein 0 < x < 0.04.

[0030] The fluorescent material can absorb 300-500 nm (near) ultraviolet light, and the emission spectrum range covers 400-700 nm, with a peak at 530 nm, showing green light emission.

[0031] Advantages of the present application

[0032] (1) In the present application, Na3YSi2O7 is selected as a matrix, Eu 2+ is used as an activator ion, and a broadband green light emitting fluorescent material is prepared by using a traditional high-temperature solid phase method. The method is simple and easy to operate, and the obtained material has good performance.

[0033] (2) In the prepared Na3YSi2O7:Eu 2+ fluorescent material, further cationic isovalent / substitution is used to adjust and control the luminescent color and luminescent intensity of the material, so that the luminescent color of a single matrix sample is adjusted from green light to cyan light, or even white light, the emission range is widened, the emission spectrum is tuned, and the application in a full-spectrum WLED is facilitated.

[0034] (3) It is verified that the Na 2.99 YSi2O7:0.01Eu product prepared in the present application has a broadband green light emitting material with obvious asymmetric emission peaks under excitation of 300-500 nm. With the change of the type and concentration of the substitution ion M, the luminescent color can be adjusted from green light to cyan light or white light, the luminescent intensity is obviously improved, and the thermal stability is improved.

[0035] (4) The preparation method is simple, practical, and easy to popularize. BRIEF DESCRIPTION OF DRAWINGS

[0036] The accompanying drawings, which form a part of this specification, are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification. The embodiments of the application, and their

[0037] Figure 1 Na3YSi2O7:xEu, x = 0.01, excitation and emission spectra.

[0038] Figure 2 Na3YSi2O7:xEu, x = 0.005, 0.01, 0.015, 0.02, 0.03, 0.04, emission spectra.

[0039] Figure 3 Na3YSi2O7:xEu, x = 0.005, 0.01, 0.015, 0.02, 0.03, 0.04, X-ray powder diffraction patterns compared with standard cards.

[0040] Figure 4 Na 2.99 Y 1-m M m Na3YSi2O7:0.01Eu, M = La, m = 0, 0.05, 0.1, 0.15, emission spectra and luminescence photographs.

[0041] Figure 5 Na 2.99 Y 1-m M m Na3YSi2O7:0.01Eu, M = Ba, m = 0, 0.1, 0.15, 0.20, emission spectra and luminescence photographs.

[0042] Figure 6 Na 2.99 Y 1-m M m Na3YSi2O7:0.01Eu, M = Hf, m = 0, 0.05, 0.1, 0.15, 0.20, emission spectra. DETAILED DESCRIPTION

[0043] It should be noted that the following detailed description is merely exemplary and is intended to provide further description of the application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0044] The application will be further described in conjunction with specific examples. It should be pointed out that the specific examples are an explanation of the application rather than a limitation.

[0045] Example 1, Na 2.99 Y 1-m M m Si2O7:xEu, take m=0, x=0.005, 0.01, 0.015, 0.02, 0.03, 0.04.

[0046] Take 0.3169 grams of NaCO3, 0.1123 grams of Y2O3 (x=0.005), 0.1129 grams of Y2O3 (x=0.01), 0.1112 grams of Y2O3 (x=0.015), 0.1107 grams of Y2O3 (x=0.02), 0.1095 grams of Y2O3 (x=0.03), 0.1084 grams of Y2O3 (x=0.04), 0.0300 grams of SiO2, and 0.0009 grams of Eu2O3 (x=0.005), 0.0018 grams of Eu2O3 (x=0.01), 0.0026 grams of Eu2O3 (x=0.015), 0.0036 grams of Eu2O3 (x=0.02), 0.0054 grams of Eu2O3 (x=0.03), 0.0072 grams of Eu2O3 (x=0.04), put the weighed raw materials into a mortar, mix with a certain amount of anhydrous ethanol, and grind thoroughly to obtain a mixed powder. Put the obtained mixed powder into an alumina crucible, heat to 1200°C under a 10% H2 / 90% N2 reducing atmosphere, and keep the temperature constant for 8 hours. After cooling to room temperature, take out the fired sample and grind uniformly to obtain a broadband green light emitting fluorescent material. The green light emitting material under 365 nm excitation is obtained according to the technical solution of Example 1. Figure 1 is the excitation and emission spectrum of Example 1 with x=0.01. The excitation spectrum covers the 300-500 nm ultraviolet-near ultraviolet light region, and the emission peak covers the 450-700 nm range, with a peak at 530 nm, which is green light emission. Figure 2 is the emission spectrum of Example 1, showing that the luminescence of the example with x=0.01 is the strongest. Figure 3 is a comparison of the X-ray powder diffraction pattern of the material sample prepared according to the technical solution of the present example with the standard card, and the results show that the prepared material is pure phase Na3YSi2O7.

[0047] Example 2, Na 2.99 Y 1-m M m Si2O7:0.01Eu, take M=La, m=0.05, 0.1, 0.15.

[0048] Take 0.3169 grams of NaCO3, 0.1016 grams of Y2O3 (m = 0.1), 0.0960 grams of Y2O3 (m = 0.15), 0.2032 grams of Y2O3 (m = 0.1), 0.0197 grams of BaCO3 (m = 0.10), 0.0296 grams of BaCO3 (m = 0.15), 0.0395 grams of BaCO3 (m = 0.20), 0.0300 grams of SiO2 and 0.0018 grams of Eu2O3, put the weighed raw materials into a mortar and mix with a certain amount of anhydrous ethanol, and grind thoroughly to obtain a mixed powder. The obtained mixed powder is loaded into an alumina crucible and heated to 1200°C under a reducing atmosphere of 10% H2 / 90% N2, and kept at a constant temperature for 8 hours. After cooling to room temperature, the fired sample is taken out and ground uniformly to obtain a broadband green light emitting fluorescent material. The emission spectrum under 365 nm excitation obtained according to the technical solution of Example 3 is as shown in the following table: Figure 4 When the M ion is La ion, as the value of m increases, the half peak width of the emission spectrum becomes wider, the emission peak value red shifts, and the luminescent color gradually changes from green light to yellowish white light.

[0049] Example 3, Na 2.99 Y 1-m M m Si2O7:0.01Eu, take M = Ba, m = 0.1, 0.15, 0.20.

[0050] Take 0.3169 grams of NaCO3, 0.1016 grams of Y2O3 (m = 0.1), 0.0960 grams of Y2O3 (m = 0.15), 0.2032 grams of Y2O3 (m = 0.1), 0.0197 grams of BaCO3 (m = 0.10), 0.0296 grams of BaCO3 (m = 0.15), 0.0395 grams of BaCO3 (m = 0.20), 0.0300 grams of SiO2 and 0.0018 grams of Eu2O3, put the weighed raw materials into a mortar and mix with a certain amount of anhydrous ethanol, and grind thoroughly to obtain a mixed powder. The obtained mixed powder is loaded into an alumina crucible and heated to 1200°C under a reducing atmosphere of 10% H2 / 90% N2, and kept at a constant temperature for 8 hours. After cooling to room temperature, the fired sample is taken out and ground uniformly to obtain a broadband green light emitting fluorescent material. The emission spectrum under 365 nm excitation obtained according to the technical solution of Example 3 is as shown in the following table: Figure 5 When the M ion is Ba ion, as the value of m increases, the half peak width of the emission spectrum becomes wider, the emission peak value red shifts, and the luminescent color gradually changes from green light to cyan light to white light.

[0051] Example 3, Na 2.99 Y 1-m M m Si2O7:0.01Eu, take M = Hf, m = 0.05, 0.1, 0.15, 0.20.

[0052] 0.1073 g of Y2O3 (m = 0.05), 0.1016 g of Y2O3 (m = 0.1), 0.0960 g of Y2O3 (m = 0.15), 0.2032 g of Y2O3 (m = 0.2), 0.0105 g of HfO2 (m = 0.05), 0.0210 g of HfO2 (m = 0.10), 0.0316 g of HfO2 (m = 0.15), 0.0421 g of HfO2 (m = 0.20), 0.0300 g of SiO2 and 0.0018 g of Eu2O3, and the weighed raw materials are put into a mortar and mixed with a certain amount of anhydrous ethanol and ground thoroughly to obtain a mixed powder. The obtained mixed powder is loaded into an alumina crucible, heated to 1200°C under a reducing atmosphere of 10% H2 / 90% N2, and kept at a constant temperature for 8 hours. After cooling to room temperature, the fired sample is taken out and ground uniformly to obtain a broadband green light emitting fluorescent material. The emission spectrum under 365 nm excitation obtained according to the technical solution of Example 4 is as shown in Figure 2. Figure 6 When the M ion is Hf ion, with the increase of m value, the emission spectrum half-peak width has no obvious change, the emission intensity is improved, and the green light is enhanced.

[0053] The above only describes the preferred embodiments of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A multicolor luminescent silicate fluorescent material, characterized in that, The chemical formula of the fluorescent material is Na 3-x Y 1- m M m Si2O7:xEu, 0 < x ≤ 0.04, 0 < m ≤ 0.2, where M is La or Ba or Hf.

2. The multicolor luminescent silicate fluorescent material as described in claim 1, characterized in that, x = 0.01, 0.05 ≤ m ≤ 0.

15.

3. The multicolor luminescent silicate fluorescent material as described in claim 1, characterized in that, x = 0.01, 0.1 ≤ m ≤ 0.

2.

4. The multicolor luminescent silicate fluorescent material as described in claim 1, characterized in that, x = 0.01, 0.05 ≤ m ≤ 0.

2.

5. The multicolor luminescent silicate fluorescent material as described in claim 1, characterized in that, The emission spectrum ranges from 400 to 700 nm.

6. The method for preparing the multicolor luminescent silicate fluorescent material as described in claim 1, characterized in that, include: The oxides or salts containing element Na, element Y, element M, element Si, and element Eu, along with an alcohol solvent, are mixed evenly and then ground to obtain a mixed powder. The mixed powder was sintered under a reducing atmosphere to obtain a multicolor luminescent silicate fluorescent material. Wherein, M is La, Ba, or Hf.

7. The method for preparing the multicolor luminescent silicate fluorescent material as described in claim 6, characterized in that, The oxide or salt containing element Na is Na2CO3; Alternatively, the oxide or salt containing element Y is Y₂O₃; Alternatively, the oxide or salt containing element M is selected from at least one of La2O3, BaCO3, and HfO2; Alternatively, the oxide or salt containing element Si is SiO2; Alternatively, the oxide or salt containing element Eu is Eu2O3.

8. The method for preparing the multicolor luminescent silicate fluorescent material as described in claim 6, characterized in that, The reducing atmosphere is a mixture of nitrogen and hydrogen.

9. The method for preparing the multicolor luminescent silicate fluorescent material as described in claim 6, characterized in that, The sintering conditions are 1200-1300 ℃, held at a constant temperature for 8-10 h.

10. A WLED device, characterized in that, include: The light source and the fluorescent material according to any one of claims 1-5.

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