Cyan-emitting phosphor, its preparation method and application

Abstract

This invention discloses a cyan emitting phosphor, its preparation method, and its applications. The chemical composition of the cyan emitting phosphor is Ba. 1.95 Mg 1‑x Ca x Si2O7:yEu 2+ Where x is the molar coefficient of Ca, 0 < x ≤ 1.0; and y is the molar coefficient of Eu, 0 < y ≤ 0.1. By combining the cyan emitting phosphor of this invention with a commercially available red phosphor and encapsulating it with a violet LED chip, a warm white light with a high color rendering index can be obtained.

Description

Technical Field

[0001] This invention relates to a cyan emitting phosphor, its preparation method and application, and more particularly to a broadband cyan emitting phosphor excited by violet light, its preparation method and application. Background Technology

[0002] To achieve full-spectrum illumination, researchers have proposed a scheme that uses ultraviolet (UV) chips to excite multicolor fluorescent conversion materials. However, prolonged exposure to UV light can be harmful to the human body. Compared to UV chips, visible-violet (VUV) LED chips (400-420nm) better meet the requirements of full-spectrum illumination, and their external efficiency is higher than that of blue LED chips. Therefore, VUV LED chips have greater research and application prospects as triggers for full-spectrum light sources. However, full-spectrum illumination technology often suffers from a lack of cyan wavelengths. Therefore, developing fluorescent conversion materials excited by violet light at different emission bands to supplement the missing components in the white LED spectrum is crucial.

[0003] CN115558493A discloses a broadband blue-cyan emitting phosphor, its preparation method, and its application; specifically, it discloses a Na... a Ca b Al 11-c Mg c O 17+d :xEu 2+ Cyan phosphor, with an excitation wavelength covering the range of 250-450 nm and a main peak located in the ultraviolet-near ultraviolet region, emits cyan fluorescence with a peak wavelength of 480-510 nm. This cyan phosphor can be used in white LED devices, but it needs to be used in conjunction with two other colored phosphors to achieve a high color rendering index.

[0004] CN117551455A discloses a full-spectrum LED health light source and device, specifically disclosing a Na3KMg7(PO4) solution. 6-x (BO3) x :yEu 2+ A broadband blue-cyan emitting phosphor can be used as a violet-excited broadband blue-cyan phosphor conversion material for full-spectrum LEDs. The full-spectrum LED described in this patent document requires the simultaneous use of the blue-cyan emitting phosphor and two other phosphors of different colors, and the color rendering index still needs further improvement.

[0005] CN117343729A discloses a cyan phosphor and its preparation method, which uses silicon dioxide, aluminum oxide, magnesium oxide, and europium oxide as raw material powders and is prepared by solid-state sintering. The cyan phosphor in this patent document can be combined with existing commercial red phosphors to obtain white light under the excitation of a violet LED chip, but the color rendering index is still relatively low.

[0006] CN114605986A discloses a violet-excited chlorosilicate blue-cyan phosphor and its preparation and application methods. Under violet light excitation, the main peak emission wavelength of this blue-cyan phosphor is in the range of 450–495 nm. This blue-cyan phosphor needs to be used simultaneously with commercial blue, green, and red phosphors, and encapsulated with a UV LED to obtain a white light source. That is, this patent document still requires combination with phosphors of various other colors; otherwise, the color rendering index will be low. Summary of the Invention

[0007] In view of this, one object of the present invention is to provide a cyan emitting phosphor, which can be used in combination with commercial red phosphor and packaged with a violet LED chip to obtain warm white light with a high color rendering index. It can effectively supplement the cyan wavelength spectrum. Another object of the present invention is to provide a method for preparing the cyan emitting phosphor as described above. Yet another object of the present invention is to provide an application of the cyan emitting phosphor as described above in a full-spectrum white LED. A further object of the present invention is to provide a white LED light source assembly. A still another object of the present invention is to provide a white LED device. The present invention achieves the above objects using the following technical solutions.

[0008] On one hand, the present invention provides a cyan emitting phosphor with the chemical composition Ba. 1.95 Mg 1-x Ca x Si2O7:yEu 2 + , where x is the molar coefficient of Ca, 0 < x ≤ 1.0; y is the molar coefficient of Eu, 0 < y ≤ 0.1.

[0009] The cyan emitting phosphor according to the present invention is preferably a solid solution phosphor.

[0010] In the cyan emitting phosphor according to the present invention, preferably, 0.2 ≤ x ≤ 0.8.

[0011] On the other hand, the present invention also provides a method for preparing the cyan emitting phosphor as described above, comprising the following steps:

[0012] 1) Provide raw materials; according to the chemical composition, mix the corresponding amounts of raw material powders to obtain a mixture; wherein, the raw materials provided include providing barium-containing inorganic substances, magnesium-containing inorganic substances, calcium-containing inorganic substances, silicon-containing inorganic substances, boron-containing inorganic substances and europium-containing inorganic substances;

[0013] 2) The mixture was sintered under a reducing atmosphere, cooled, and then ground to obtain cyan emitting phosphor.

[0014] According to the preparation method of the present invention, preferably, the sintering temperature is 1000-1500℃ and the sintering time is 3-6h.

[0015] According to the preparation method of the present invention, preferably, in step 1), the barium-containing inorganic material is selected from at least one of barium oxide and barium carbonate; the magnesium-containing inorganic material is selected from at least one of magnesium oxide and magnesium carbonate; the calcium-containing inorganic material is selected from at least one of calcium oxide and calcium carbonate; the silicon-containing inorganic material is selected from at least one of silicon oxide and silicates; the boron-containing inorganic material is selected from at least one of boron trioxide and boric acid; and the europium-containing inorganic material is selected from at least one of europium oxide and europium carbonate.

[0016] In another aspect, the present invention also provides an application of the cyan emitting phosphor as described above in a full-spectrum white LED, wherein the cyan emitting phosphor exhibits broadband cyan light emission under violet light excitation, with an emission wavelength range of 480–520 nm.

[0017] In another aspect, the present invention also provides a white LED light source assembly, which includes the cyan emitting phosphor as described above, and includes a red emitting phosphor and a violet LED chip.

[0018] In the white LED light source assembly according to the present invention, preferably, the red emitting phosphor is a nitride red phosphor.

[0019] In another aspect, the present invention also provides a white LED device, which includes the white LED light source assembly as described above.

[0020] The cyan emitting phosphor of this invention, with its specific composition, can be used alone in combination with commercial red phosphor and encapsulated with a violet LED chip to obtain warm white light with a high color rendering index. A warm white light with a color rendering index of 92.7 and a color temperature of approximately 3300K can be obtained. This effectively supplements the cyan wavelength spectrum and can be used as a violet-excited cyan phosphor conversion material for full-spectrum LEDs. Compared with existing technologies, this invention eliminates the need for combining multiple phosphors of other colors, thus simplifying the composition of full-spectrum white LED devices. Furthermore, the preparation method of the cyan emitting phosphor of this invention is simple, which is beneficial for its widespread application. Attached Figure Description

[0021] Figure 1 The images show the X-ray diffraction data of the cyan emitting phosphors in Examples 1 to 3.

[0022] Figure 2 This is a scanning electron microscope (SEM) image of the cyan emitting phosphor from Example 1.

[0023] Figure 3 The image shows the elemental X-ray energy dispersive spectroscopy results of the cyan emitting phosphor in Example 1.

[0024] Figure 4 The steady-state emission and excitation spectra of the cyan emitting phosphors in Examples 1 to 3 are shown.

[0025] Figure 5 The electroluminescence spectrum of the white LED prepared in Experiment Example 1 is shown.

[0026] Figure 6 The CIE color coordinate diagram of the white LED prepared in Experiment Example 1. Detailed Implementation

[0027] The present invention will be further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0028] The cyan emitting phosphor of this invention can be used in full-spectrum white LEDs, effectively supplementing the cyan wavelength spectrum. Compared to existing technologies, in obtaining full-spectrum white light, the cyan emitting phosphor of this invention does not need to be used simultaneously with multiple other colored phosphors. The cyan emitting phosphor of this invention can obtain warm white light with a low color temperature by using only one red emitting phosphor. This simplifies the composition of full-spectrum white LED devices. Furthermore, it has a high color rendering index (CRI). The CRI is greater than 91, preferably greater than or equal to 92. This is not a conventional choice.

[0029] <Cyan fluorescent powder>

[0030] The chemical composition of the cyan emitting phosphor of this invention is Ba. 1.95 Mg 1-x Ca x Si2O7:yEu 2+ Where x is the molar coefficient of Ca, 0 < x ≤ 1.0; preferably, 0.1 ≤ x ≤ 0.9, more preferably, 0.2 ≤ x ≤ 0.8, and even more preferably, 0.3 ≤ x ≤ 0.7. y is the molar coefficient of Eu, 0 < y ≤ 0.1, preferably, 0.01 ≤ y ≤ 0.1, and more preferably, 0.02 ≤ y ≤ 0.08. This cyan emitting phosphor is used only in combination with commercial red phosphors and packaged with violet LED chips to obtain warm white light with a high color rendering index. For example, under the excitation of a 400nm violet LED chip, it exhibits broadband cyan emission, effectively supplementing the cyan wavelength spectrum, while also complementing (Ca,Sr)SiAlN3:Eu 2+ When used in combination, red commercial phosphors can produce high-quality white light with a color rendering index Ra of 92.7, a color temperature of 3322K, and color coordinates of (0.4251, 0.4183).

[0031] The cyan emitting phosphor of this invention is a solid solution phosphor. The particle size of the cyan emitting phosphor can be 20–75 μm.

[0032] <Preparation Method>

[0033] The present invention also provides a method for preparing the cyan emitting phosphor as described above, comprising the following steps: (1) providing raw materials and mixing steps; (2) sintering and grinding steps. These are described in detail below.

[0034] <Provide raw materials and mixing steps>

[0035] Provide raw materials; according to the chemical composition, mix the corresponding amounts of raw material powders to obtain a mixture; wherein, the raw materials provided include providing barium-containing inorganic substances, magnesium-containing inorganic substances, calcium-containing inorganic substances, silicon-containing inorganic substances, boron-containing inorganic substances and europium-containing inorganic substances.

[0036] In this invention, the barium-containing inorganic material is selected from at least one of barium oxide and barium carbonate, preferably barium carbonate (BaCO3). The magnesium-containing inorganic material is selected from at least one of magnesium oxide and magnesium carbonate, preferably magnesium oxide (MgO). The calcium-containing inorganic material is selected from at least one of calcium oxide and calcium carbonate, preferably calcium carbonate (CaCO3). The silicon-containing inorganic material is selected from at least one of silicon oxide and silicates, preferably silicon oxide (SiO2). The boron-containing inorganic material is selected from at least one of boron trioxide and boric acid, preferably boric acid (H3BO3). The europium-containing inorganic material is selected from at least one of europium oxide and europium carbonate, preferably europium oxide (Eu2O3).

[0037] In this invention, the chemical composition refers to the chemical composition of the cyan emitting phosphor described above.

[0038] In this invention, the mixture can be homogenized by grinding.

[0039] <Sintering and Grinding Steps>

[0040] The mixture was sintered under a reducing atmosphere, cooled, and then ground to obtain cyan emitting phosphor.

[0041] The sintering temperature can be 1000–1500℃, preferably 1000–1400℃, and more preferably 1100–1200℃. The sintering time can be 3–6 h, preferably 3.5–5.5 h, and more preferably 4–5 h.

[0042] A reducing atmosphere refers to an atmosphere formed by introducing a mixture of hydrogen and an inert gas. The volume ratio of hydrogen to inert gas can be 5–10:90–95, for example, 5:95. The inert gas can be any one of nitrogen, argon, or helium.

[0043] In this invention, after sintering, the product is allowed to cool naturally to room temperature. The sintered product is then removed and ground to obtain cyan emitting phosphor.

[0044] <Application>

[0045] The present invention also provides an application of the cyan emitting phosphor as described above in a full-spectrum white LED. Under violet light excitation, the cyan emitting phosphor exhibits broadband cyan light emission with an emission wavelength range of 480–520 nm.

[0046] In some specific implementations, when excited by a 400nm violet LED chip, the cyan emitting phosphor exhibits broadband cyan emission, effectively supplementing the cyan wavelength spectrum.

[0047] <White LED Light Source Components>

[0048] The present invention also provides a white LED light source assembly, which includes the cyan emitting phosphor as described above, and a red emitting phosphor and a violet LED chip.

[0049] According to one embodiment of the present invention, the red emitting phosphor is a nitride red phosphor [(Ca,Sr)SiAlN3:Eu].

[0050] <White LED Devices>

[0051] The present invention also provides a white LED device, which includes the white LED light source assembly as described above.

[0052] The testing method is described below:

[0053] XRD determination: The X'Pert PRO XRD powder diffractometer manufactured by Panalytical was used for the test.

[0054] Scanning electron microscopy measurements: The Sigma 500 field emission scanning electron microscope manufactured by ZEISS was used for the measurements.

[0055] Steady-state emission and excitation spectra were measured using an Edinburgh Instruments FSL1000 steady-state / transient fluorescence spectrometer.

[0056] Electroluminescence spectroscopy measurement: The PCE-2000A photoelectric color comprehensive testing system manufactured by Hangzhou Yuanfang Optoelectronic Information Co., Ltd. was used for testing.

[0057] Color rendering index determination: The PCE-2000A photoelectric color comprehensive testing system produced by Hangzhou Yuanfang Optoelectronic Information Co., Ltd. was used for testing.

[0058] Example 1

[0059] The chemical composition of the cyan emitting phosphor in this embodiment is Ba.1.95 Mg 0.7 Ca 0.3 Si2O7:0.07Eu 2+ Its preparation method includes the following steps:

[0060] The raw materials are BaCO3, MgO, CaCO3, SiO2, H3BO3 and Eu2O3; according to their chemical composition, the corresponding amounts of raw material powders are mixed to obtain a mixture.

[0061] The mixture was sintered at 1200℃ for 4 hours under a reducing atmosphere, then naturally cooled to room temperature and ground to obtain cyan emitting phosphor.

[0062] The cyan emitting phosphor of this embodiment was tested:

[0063] The X-ray diffraction data results are shown below. Figure 1 The results showed that it was a pure phase;

[0064] The scanning electron microscope results are shown in Figure 2 The elemental results of the X-ray energy dispersive spectroscopy are shown in [the table]. Figure 3 .from Figure 2 and Figure 3 As can be seen, the particle size of the cyan emitting phosphor in this embodiment is about 50 μm, and the corresponding EDS elemental scan confirms its chemical composition.

[0065] The steady-state emission spectrum and excitation spectrum results are shown in Figure 4 .

[0066] The electroluminescence spectra of the prepared full-spectrum white LED device are shown in the figure. Figure 5 .like Figure 5 As shown, the steady-state emission spectrum of the cyan emitting phosphor obtained in this example under 400nm violet light excitation was measured using an FLS1000 fluorescence spectrometer, exhibiting broadband emission with the center wavelength in the cyan band.

[0067] Example 2

[0068] The only difference from Example 1 is the chemical composition. The cyan emitting phosphor in this example has the chemical composition Ba. 1.95 Mg 0.5 Ca 0.5 Si2O7:0.07Eu 2+ .

[0069] The XRD results of the obtained cyan emitting phosphor are shown in the figure. Figure 1 The steady-state emission spectrum and excitation spectrum results are shown in Figure 4 X-ray diffraction data indicate that it is a pure phase.

[0070] Example 3

[0071] The only difference from Example 1 is the chemical composition. The cyan emitting phosphor in this example has the chemical composition Ba. 1.95 Mg 0.3 Ca 0.7 Si2O7:0.07Eu 2+ .

[0072] The XRD results of the obtained cyan emitting phosphor are shown in the figure. Figure 1 The steady-state emission spectrum and excitation spectrum results are shown in Figure 4 X-ray diffraction data indicate that it is a pure phase.

[0073] Application Experiment Example 1

[0074] The cyan emitting phosphor obtained in Example 1 and the commercially available red phosphor CaAlSiN3:Eu were used. 2+ A full-spectrum white LED device was fabricated by encapsulating it on a 400nm violet LED chip. Under the excitation of the 400nm violet LED chip, the cyan emitting phosphor exhibits broadband cyan emission, effectively supplementing the cyan wavelength spectrum.

[0075] like Figure 5 and Figure 6 As shown, the cyan emitting phosphor of Example 1 is used to couple a violet LED chip (wavelength 400nm), while simultaneously introducing commercially available red phosphor CaAlSiN3:Eu 2+ High-quality warm white light was obtained, with a color rendering index (Ra) of 92.7, a color temperature of 3322K, and color coordinates of (0.4251, 0.4183). This demonstrates that the cyan emitting phosphor of this invention can fill the "cyan gap" (480–520 nm) in the spectrum, thereby obtaining warm white light with a high CRI and low color temperature.

[0076] This invention is not limited to the above-described embodiments. Any modifications, improvements, or substitutions that can be conceived by those skilled in the art without departing from the essential content of this invention fall within the scope of this invention.

Claims

1. A white LED light source assembly, characterized in that, It includes cyan emitting phosphor, red emitting phosphor and violet LED chip; The cyan emitting phosphor is used only in combination with the red emitting phosphor, without the need to use multiple other colors of phosphor. When packaged with a purple LED chip, warm white light with a high color rendering index can be obtained. The chemical composition of the cyan emitting phosphor is as follows: Three 1.95 Mg 1-x Ca x Si2O7:yEu 2+ , Where x is the molar coefficient of Ca, 0.1≤x≤0.9; and y is the molar coefficient of Eu, 0.07≤y≤0.

08. When excited by violet light, the cyan emitting phosphor exhibits broadband cyan light emission with an emission wavelength range of 480–520 nm. The red emitting phosphor is CaAlSiN3:Eu 2+ Nitride red fluorescent powder; The color rendering index of the white LED light source component is greater than 91.

2. The white LED light source assembly according to claim 1, characterized in that, 0.2≤x≤0.8。 3. The white LED light source assembly according to claim 1, characterized in that, The cyan emitting phosphor is a solid solution phosphor.

4. The white LED light source assembly according to claim 1, characterized in that, The preparation method of the cyan emitting phosphor includes the following steps: 1) Provide raw materials; according to the chemical composition, mix the corresponding amounts of raw material powders to obtain a mixture; wherein, the raw materials provided include providing barium-containing inorganic substances, magnesium-containing inorganic substances, calcium-containing inorganic substances, silicon-containing inorganic substances, boron-containing inorganic substances and europium-containing inorganic substances; 2) The mixture was sintered under a reducing atmosphere, cooled, and then ground to obtain cyan emitting phosphor.

5. The white LED light source assembly according to claim 4, characterized in that, In step 2), the sintering temperature is 1000-1500℃ and the sintering time is 3-6h.

6. The white LED light source assembly according to claim 4, characterized in that, In step 1), the barium-containing inorganic substance is selected from at least one of barium oxide and barium carbonate; the magnesium-containing inorganic substance is selected from at least one of magnesium oxide and magnesium carbonate; the calcium-containing inorganic substance is selected from at least one of calcium oxide and calcium carbonate; the silicon-containing inorganic substance is selected from at least one of silicon oxide and silicates; the boron-containing inorganic substance is selected from at least one of boron trioxide and boric acid; and the europium-containing inorganic substance is selected from at least one of europium oxide and europium carbonate.

7. A white LED device, characterized in that, It includes the white LED light source assembly as described in claim 1.

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