Purple light excited cyan light fluorescent powder as well as preparation method and application thereof

Abstract

The invention relates to purple light excited cyan light fluorescent powder as well as a preparation method and application thereof. The cyan light emitting fluorescent powder belongs to an AO-Si3N4-Sb2O5-EuO system. Wherein A comprises one or more of Ca, Sr and Ba; the molar ratio of AO to Si3N4 to Sb2O5 to EuO in the purple light excited cyan light fluorescent powder is (0.9 to 0.95) to (0.57 to 0.66) to (0.005 to 0.1) to (0.025 to 0.1). The preparation method comprises the following steps: respectively weighing an A-containing compound, Si3N4, an Sb-containing oxide and an Eu-containing oxide as raw material powder, mixing, uniformly grinding, sintering in a reducing atmosphere, and cooling to room temperature to obtain the purple light excited cyan light fluorescent powder. Compared with the prior art, the blue light emitting fluorescent material can cover a wider emission spectrum range, and the urgent requirement of the current white light LED field on a blue light emitting fluorescent material is met.

Description

Technical Field

[0001] The invention relates to the technical field of fluorescent materials, and in particular to a violet light-excited cyan fluorescent powder and a preparation method and application thereof. Background Art

[0002] White light emitting diodes (W-LEDs) have become the star of future lighting technology due to their excellent luminous efficiency, long life, environmental protection and stability, and are widely used in the field of solid-state lighting. At present, commercial white light LEDs mainly rely on blue LED chips and yellow phosphors (YAG:Ce 3+ ) is achieved by a combination of 2. However, the cold white light produced by this method often has the defects of high color temperature (CCT) and low color rendering index (CRI) due to insufficient red spectral components. In order to solve this problem, related studies have proposed a method based on purple light chips, combining red, green and blue phosphors. However, the emission spectra of these purple light-excited white light LEDs have obvious omissions in the cyan band of 480-520nm, which greatly reduces their CRI values ​​and limits their application in high-quality lighting. Therefore, it is particularly important to develop efficient purple light-excited cyan phosphors to make up for the insufficient cyan spectrum of purple warm white light LEDs, thereby greatly improving their color rendering index. However, research on this cyan phosphor is still insufficient.

[0003] Patent publication number CN113736463A discloses a cyan fluorescent powder excited by violet light, and its preparation method and application. The cyan fluorescent powder belongs to the BaO-La2O3-SiO2-EuO system, wherein the mass percentage of each oxide is: 66.77%≤BaO≤66.93%, 15.29%≤La2O3≤15.60%, 17.44%≤SiO2≤17.48%, 0.16%≤EuO≤0.48%. During preparation, the raw material powder is weighed according to the metering ratio, mixed evenly, and ground. After grinding, the ground raw material is loaded into an alumina crucible, and buried in an alumina crucible filled with carbon powder, and reduced and sintered at high temperature to obtain cyan fluorescent powder excited by violet light. The raw material of the cyan fluorescent powder does not contain N and Sb elements, and CO is used for reduction during the preparation process. The emission spectrum obtained has a wide range, but the monochromaticity is poor.

[0004] Therefore, in order to meet the urgent needs of white light LED / sunlight-like LED / full spectrum LED / health lighting LED light sources and cover a wider emission spectrum range, it is urgent to develop new cyan light-emitting fluorescent materials. Summary of the invention

[0005] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and provide a violet light-excited cyan phosphor and its preparation method and application to cover a wider emission spectrum range and meet the current urgent demand for cyan light-emitting fluorescent materials in the white light LED field.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] One of the technical solutions of the present invention is to provide a violet light-excited cyan phosphor, which belongs to the AO-Si3N4-Sb2O5-EuO system; wherein A includes one or more of Ca, Sr and Ba;

[0008] The molar ratio of each substance in the violet light excited cyan fluorescent powder is AO: Si3N4: Sb2O5: EuO = 0.9-0.95: 0.57-0.66: 0.005-0.1: 0.025-0.1.

[0009] Furthermore, the excitation band of the violet light-excited cyan phosphor covers 250-500nm.

[0010] Furthermore, the peak value of the excitation band of the cyan phosphor excited by violet light is 420-440nm.

[0011] Furthermore, the emission spectrum of the violet light-excited cyan phosphor under ultraviolet excitation covers a range of 450-550 nm, with a central wavelength at 490-495 nm.

[0012] Furthermore, the central wavelength of the emission spectrum of the violet light-excited cyan phosphor under ultraviolet excitation is at 493 nm.

[0013] Furthermore, the violet light-excited cyan phosphor maintains 80% to 90%, preferably 82% to 88%, of the optimal emission intensity under excitation at 400nm; and maintains more than 91%, preferably 91% to 98% of the optimal emission intensity under excitation at 410nm.

[0014] The second technical solution of the present invention is to provide a method for preparing a violet light-excited cyan phosphor, which comprises weighing a compound containing A, Si3N4, an Sb oxide and an Eu oxide as raw material powders, mixing them and grinding them evenly, sintering them in a reducing atmosphere, and cooling them to room temperature to obtain the violet light-excited cyan phosphor.

[0015] Further, the A-containing compound includes an oxide or carbonate of A;

[0016] The Sb-containing compound is an oxide of Sb;

[0017] The Eu-containing compound is an oxide of Eu.

[0018] Further, the oxide of A includes CaO, SrO, and BaO;

[0019] The carbonate of A includes CaCO3, SrCO3, and BaCO3;

[0020] The oxide of Sb is Sb2O5;

[0021] The oxide of Eu is EuO.

[0022] Furthermore, the molar ratio of the oxide component of A, Si3N4, Sb oxide and Eu oxide in the oxide of A or the carbonate of A is AO:Si3N4:Sb2O5:EuO=0.9-0.95:0.57-0.66:0.015-0.1:0.025-0.1.

[0023] Furthermore, the sintering temperature is 1200-1400° C., and the sintering time is 6-12 hours.

[0024] Furthermore, the grinding time is 20-40 min.

[0025] Furthermore, the reducing atmosphere is a mixture of hydrogen and nitrogen.

[0026] Furthermore, the hydrogen-nitrogen mixed gas is a 5% H2 / 90% N2 mixed gas.

[0027] The third technical solution of the present invention is to provide an application of violet light-excited cyan phosphor, wherein the violet light-excited cyan phosphor is assembled with a chip into an LED lighting device.

[0028] Furthermore, the violet light-excited cyan phosphor is used for preparing violet light chip-type solar light LED, violet light chip full-spectrum LED or violet light chip high-quality white light LED.

[0029] Compared with the prior art, the present invention has the following advantages:

[0030] (1) The violet light-excited cyan phosphor prepared by the present invention emits a spectrum in the range of 450-550nm under ultraviolet light excitation, and the cyan light with a central wavelength at 493nm is broadband emission, which broadens the range of the emission spectrum.

[0031] (2) The violet light-excited cyan phosphor of the present invention is Eu 2+ The doped cyan light-emitting phosphor has the advantage of stable physical and chemical properties. At the same time, the phosphor can be prepared by a conventional solid-phase reaction method, has the characteristics of simple preparation process and is conducive to industrial production. It is a good candidate material that can be widely used.

[0032] (3) The emission wavelength of the violet light-excited cyan phosphor of the present invention includes 450 to 550 nm, and can effectively absorb light in the wavelength range of 200 to 500 nm. It has the characteristics of a wide emission spectrum range and can be well matched with existing commercial near-ultraviolet LED chips. It is suitable for the application of violet chip white light LED, violet chip solar LED, violet chip full-spectrum LED and violet chip high-quality white light LED.

[0033] (4) Due to Eu 2+ The luminescence energy level of Eu is attributed to the fd electron transition. The 5d orbit of its electron is in the outer layer and is easily affected by the coordination crystal field. Therefore, the regulation of the coordination crystal field can realize the 2+ The excitation and emission spectra are clipped, so Eu 2+ Commonly used as an activator for phosphors, Eu 2+ Ions have become important doping ions in rare earth doped phosphors. In addition, oxynitride phosphors have been widely used in LEDs due to their excellent fluorescence properties and good stability.

[0034] (5) The present invention dopes Sb ions into the system to improve the luminescence intensity and the absorption intensity in the purple light region by changing the crystal field environment of the matrix material. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 The photoexcitation spectra of the violet light excited cyan phosphors of Examples 1 and 4 and Comparative Example 1 of the present invention are shown;

[0036] Figure 2 The photoemission spectra of the cyan phosphor excited by violet light of Examples 1-5 and Comparative Example 1 of the present invention are shown. DETAILED DESCRIPTION

[0037] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and a detailed implementation method and a specific operation process are given, but the protection scope of the present invention is not limited to the following embodiments. Based on the given embodiments, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0038] Unless otherwise specified, the reagents, methods, instruments and equipment used in the present invention are conventional reagents, methods, instruments and equipment in the art.

[0039] Implementation Case 1:

[0040] This embodiment provides a violet light excited cyan phosphor, which belongs to the AO-Si3N4-Sb2O5-EuO system, and the specific preparation method is as follows:

[0041] S1: BaCO3, Si3N4, Sb2O5, and Eu2O3 are selected as starting materials, Ba:Si:Sb:Eu=0.95:1.97:0.03:0.05 (molar ratio), wherein BaO:Si3N4:Sb2O5:EuO=0.95:0.66:0.015:0.025 (molar ratio). BaCO3, Si3N4, Sb2O5, and Eu2O3 are weighed respectively, and the total mass of the raw material mixture is controlled to be 10 g.

[0042] S2: Grind the raw material mixture in an agate mortar for 30 minutes. After the materials are evenly mixed, load the mixture into an alumina crucible. Then, place the alumina crucible containing the raw materials in a reducing atmosphere of hydrogen and calcine at 1200° C. for 8 hours, then cool to room temperature to obtain the target product.

[0043] The spectral properties of the phosphor in this system were tested using a fluorescence spectrometer (HITACHI F-7000). Figure 1 and Figure 2 As shown. The results show that the phosphor of this system has a wide excitation band, covering the ultraviolet, purple and blue light regions (250-500nm), with a peak near 436nm and a high spectral peak, indicating that it can be effectively excited by purple and blue light chips and matches well with UV LED chips. Under the excitation of a 410nm purple light source, the phosphor emits bright cyan light, and the emission spectrum is between 450-550nm, with a peak at 493nm.

[0044] Implementation Case 2:

[0045] This embodiment provides a violet light excited cyan phosphor. The reaction conditions and steps are basically the same as those in Embodiment 1, except that SrCO3 is added to the raw material and BaCO3 is removed:

[0046] Select SrCO3, Si3N4, Sb2O5, and Eu2O3 as starting materials, Sr:Si:Sb:Eu=0.95:1.97:0.03:0.05 (molar ratio), wherein SrO:Si3N4:Sb2O5:EuO=0.95:0.66:0.015:0.025 (molar ratio). Weigh the four raw materials separately, and control the total mass of the raw material mixture to be 10g of mixed raw materials. Grind the above raw material mixture in an agate mortar for 30 minutes. After the materials are evenly mixed, load the mixture into an alumina crucible, and then place the alumina crucible containing the raw materials in a reducing atmosphere of hydrogen for calcination at 1200°C for 10 hours, and then cool to room temperature to obtain the target product. The fluorescence spectrum properties of the cyan luminescent material are similar to those in Example 1, such as Figure 1 and 2 shown.

[0047] Implementation Case 3:

[0048] This embodiment provides a violet light excited cyan phosphor. The reaction conditions and steps are basically the same as those in Embodiment 1, except that CaCO3 is added to the raw materials and BaCO3 is removed:

[0049] Select CaCO3, Si3N4, Sb2O5 and Eu2O3 as starting raw materials, and weigh the raw materials with a molar ratio of Ca:Si:Sb:Eu=0.95:1.99:0.03:0.05, wherein CaO:Si3N4:Sb2O5:EuO=0.95:0.66:0.015:0.025 (molar ratio). Separately weigh the four raw materials to control the total mass of the raw material mixture to be 10g of mixed raw materials. Grind the above raw material mixture in an agate mortar for 30 minutes. After the materials are evenly mixed, load the mixture into an alumina crucible, and then place the alumina crucible containing the raw materials in a reducing atmosphere of hydrogen for calcination at 1200°C for 10 hours, and then cool to room temperature to obtain the target product. The fluorescence spectrum properties of the cyan luminescent material are similar to those in Example 1, such as Figure 2 shown.

[0050] Implementation Case 4:

[0051] This embodiment provides a violet light-excited cyan phosphor. The reaction conditions and steps are basically the same as those in Embodiment 1, except that the doping ratio of the Sb element in the raw material is reduced:

[0052] BaCO3, Si3N4, Sb2O5 and Eu2O3 were selected as starting raw materials, and the molar ratio of the raw materials was weighed to be Ba:Si:Sb:Eu=0.95:1.99:0.01:0.05, wherein BaO:Si3N4:Sb2O5:EuO=0.95:0.66:0.005:0.025 (molar ratio). The four raw materials were weighed separately to control the total mass of the raw material mixture to be 10g of mixed raw materials. The above raw material mixture was placed in an agate mortar and ground for 30 minutes. After the materials were evenly mixed, the mixture was loaded into an alumina crucible. The alumina crucible containing the raw materials was then placed in a reducing atmosphere of hydrogen and calcined at 1200°C for 10 hours, and then cooled to room temperature to obtain the target product. The fluorescence spectrum properties of the cyan luminescent material are similar to those in Example 1, such as Figure 1 and 2 Shown

[0053] Implementation Case 5:

[0054] This embodiment provides a violet light-excited cyan phosphor. The reaction conditions and steps are basically the same as those in embodiment 1, except that the Sb element is added to the raw material in a doping ratio of:

[0055] BaCO3, Si3N4, Sb2O5 and Eu2O3 were selected as starting raw materials, and the molar ratio of the raw materials was weighed to be Ba:Si:Sb:Eu=0.95:1.90:0.1:0.05, wherein BaO:Si3N4:Sb2O5:EuO=0.95:0.63:0.05:0.025 (molar ratio). The four raw materials were weighed separately to control the total mass of the raw material mixture to be 10 g of mixed raw materials. The above raw material mixture was placed in an agate mortar and ground for 30 minutes. After the materials were evenly mixed, the mixture was loaded into an alumina crucible. The alumina crucible containing the raw materials was then placed in a reducing atmosphere of hydrogen and calcined at 1200°C for 10 hours, and then cooled to room temperature to obtain the target product. The fluorescence spectrum properties of the cyan luminescent material are similar to those in Example 1, such as Figure 2 shown.

[0056] Comparative Case 1

[0057] This comparative example 1 provides a violet light-excited cyan phosphor, and the reaction conditions and steps are basically the same as those of the implementation example 1, except that no Sb element is added to the raw materials:

[0058] BaCO3, Si3N4 and Eu2O3 were selected as starting raw materials, and the molar ratio of the raw materials was weighed to be Ba:Si:Eu=0.95:2.0:0.05, wherein BaO:Si3N4:EuO=0.95:0.66:0.025 (molar ratio). The four raw materials were weighed separately to control the total mass of the raw material mixture to be 10g of mixed raw materials. The above raw material mixture was placed in an agate mortar and ground for 30 minutes. After the materials were evenly mixed, the mixture was loaded into an alumina crucible. The alumina crucible containing the raw materials was then placed in a reducing atmosphere of hydrogen and calcined at 1200°C for 10 hours, and then cooled to room temperature to obtain the target product. The fluorescence spectrum properties of the cyan luminescent material are as follows: Figure 1 and 2 shown.

[0059] Although the present invention has been described in detail above by means of general description, specific implementation methods and tests, it is obvious to those skilled in the art that some modifications or improvements may be made to the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection claimed by the present invention.

Claims

1. A violet light excited cyan phosphor, characterized in that: The cyan emitting phosphor belongs to the AO-Si3N4-Sb2O5-EuO system; wherein A includes one or more of Ca, Sr and Ba; The molar ratio of each substance in the violet light excited cyan fluorescent powder is AO: Si3N4: Sb2O5: EuO = 0.9-0.95: 0.57-0.66: 0.005-0.1: 0.025-0.

1.

2. The violet light-excited cyan phosphor according to claim 1, characterized in that: The excitation band of the violet light-excited cyan-emitting phosphor covers 250-500 nm.

3. The violet light-excited cyan phosphor according to claim 1, characterized in that: The emission spectrum of the violet light-excited cyan phosphor under ultraviolet excitation covers a range of 450-550nm, with a central wavelength at 490-495nm.

4. The violet light-excited cyan phosphor according to claim 3, characterized in that: The violet light-excited cyan fluorescent powder maintains 80% to 90% of the optimal emission intensity under excitation at 400nm, and maintains more than 91% of the optimal emission intensity under excitation at 410nm.

5. The method for preparing a violet light excited cyan phosphor according to any one of claims 1 to 4, characterized in that: The compound A, Si3N4, Sb oxide and Eu oxide are weighed as raw material powders respectively, mixed and ground evenly, sintered in a reducing atmosphere, and cooled to room temperature to obtain the violet light-excited cyan phosphor.

6. The method for preparing a violet light excited cyan phosphor according to claim 5, characterized in that: The A-containing compound includes an oxide or carbonate of A; The Sb-containing compound is an oxide of Sb; The Eu-containing compound is an oxide of Eu.

7. The method for preparing a violet light excited cyan phosphor according to claim 6, characterized in that: The oxide of A includes CaO, SrO, and BaO; The carbonate of A includes CaCO3, SrCO3, and BaCO3; The Sb oxide is Sb2O5; The oxide of Eu is EuO.

8. The method for preparing a violet light excited cyan phosphor according to claim 7, characterized in that: The molar ratio of the oxide component of A, Si3N4, Sb oxide and Eu oxide in the oxide of A or the carbonate of A is AO:Si3N4:Sb2O5:EuO=0.9-0.95:0.57-0.66:0.015-0.1:0.025-0.

1.

9. The method for preparing a violet light excited cyan phosphor according to claim 5, characterized in that: The sintering temperature is 1200-1400°C and the sintering time is 6-12h; The reducing atmosphere is a mixture of 5% H2 / 90% N2.

10. The use of a violet light excited cyan phosphor as claimed in any one of claims 1 to 4, characterized in that: The purple light excites the cyan fluorescent powder and the chip to assemble an LED lighting device.

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