Ba6B4O9N2 crystal, fluorescent powder taking Ba6B4O9N2 crystal as matrix, ceramic chip and preparation method

Abstract

The invention belongs to the technical field of luminescent materials, and particularly relates to a Ba6B4O9N2 crystal, fluorescent powder taking the Ba6B4O9N2 crystal as a matrix, a ceramic chip and a preparation method, the crystal is an orthorhombic crystal system, the cell parameter # imgabs0 # Z is 6, and the space group is P-4b2. The fluorescent powder is prepared by taking Ba6B4O9N2 as a matrix material and adopting a high-temperature solid-phase method under normal pressure, has a brand-new structure and chemical composition, takes Eu < 2 + > as an active ion, can be excited by near ultraviolet and blue light, has an emission peak at 620 nm, belongs to orange red emission fluorescent powder, and meets the requirements on red fluorescent powder at present; the prepared fluorescent ceramic chip emits bright red light under the excitation of 400nm laser.

Description

Technical Field

[0001] The present invention belongs to the technical field of luminescent materials, and in particular relates to a Ba6B4O9N2 crystal, a phosphor using the Ba6B4O9N2 crystal as a matrix, a ceramic sheet and a preparation method thereof. Background Art

[0002] Luminescent materials that absorb blue light and emit visible light have always been the basic research direction of white light emitting diodes (LEDs). The development of new fluorescent materials (wavelength conversion materials) based on the characteristics of blue light-excited phosphors has also received increasing attention. Nitrogen (oxy) compound phosphor materials have many advantages, such as high luminous efficiency, effective excitation by visible light, strong designability of fluorescent properties, high thermal stability and environmental friendliness, and therefore have become important candidate materials for phosphors used in white light LEDs. Certain d→f transition rare earth ions such as Eu 2+ 、Ce 3+ and Yb 2+ In nitrogen (oxygen) compounds, their excitation and emission bands often undergo red shifts. As their components change, they have high luminescence characteristics in the green-red light range, which makes up for the defects of low color rendering index and high color temperature caused by the lack of red light in commercial blue light chips and YAG yellow phosphor solutions. Therefore, nitrogen (oxygen) compounds are relatively potential matrices in the research of orange-red phosphors for white light LEDs, and the luminescence spectrum of this type of phosphor can cover the entire visible light region, which is suitable for matching with Ga(In)N chips to manufacture white light LEDs.

[0003] Since the end of the 20th century, nitride (oxy) phosphors with various matrix structures have been discovered and reported one after another. Optimize the known nitride (oxy) phosphors, explore simple preparation technologies, equipment and routes with mild process conditions, low cost and suitable for industrial mass production; explore new nitride (oxy) phosphors, obtain phosphors with new luminescent properties to meet the needs of more scenarios. Therefore, it is urgent to develop methods to obtain more corresponding matrix materials and provide more fluorescent material options. Summary of the invention

[0004] In view of the deficiencies of the above-mentioned prior art, the present invention provides a Ba6B4O9N2 crystal and a phosphor and a ceramic sheet using the Ba6B4O9N2 crystal as a matrix and a preparation method thereof. The specific technical scheme is as follows:

[0005] The first object of the present invention is to provide a Ba6B4O9N2 crystal, wherein the crystal is an orthorhombic system, and the unit cell parameters are Z=6, space group is P-4b2.

[0006] The second object of the present invention is to provide a phosphor having a chemical formula of Ba 6-X B4O9N2:xEu 2+, where 0≤x≤6.

[0007] The phosphor of the present invention uses Ba6B4O9N2 crystal as the matrix material, has a brand-new structure and chemical composition, and is based on Eu 2+ As an activation ion, the phosphor can be excited by blue light. The excitation spectrum of the phosphor is in the range of 350 to 550 nm, the emission spectrum is in the range of 550 to 750 nm, the main emission peak is at 620 nm, and it is an orange-red emitting phosphor, which meets the current demand for red phosphor.

[0008] The third object of the present invention is to provide a fluorescent ceramic sheet prepared from the above fluorescent powder.

[0009] A fourth object of the present invention is to provide a method for preparing the above-mentioned Ba6B4O9N2 crystal, comprising the following steps:

[0010] According to the stoichiometric ratio of Ba6B4O9N2, weigh BaO, H3BO3, and BN raw materials under a protective gas atmosphere, and then mix and grind the raw materials evenly; put the ground powder into a crucible and seal it, then put the crucible into a high-temperature tube furnace, and sinter it in a reducing atmosphere of N2 / H2 at 1200-1650°C for 5-12 hours, then cool it to 900-1100°C, and wait until the temperature drops to room temperature to obtain nitrogen oxide Ba6B4O9N2 crystals.

[0011] A fifth object of the present invention is to provide a method for preparing the above-mentioned phosphor, comprising the following steps:

[0012] BaO, H3BO3, BN and Eu2O3 raw materials are weighed under a protective gas atmosphere, and then the raw materials are fully mixed and ground evenly; the ground mixture is placed in a crucible, packaged, and transferred to a high-temperature tube furnace, sintered in a reducing atmosphere of a N2 / H2 mixed gas at 1200-1650°C for 3-30 hours, and then naturally cooled to room temperature to obtain an orange-red emitting nitrogen oxide phosphor.

[0013] Generally speaking, BN is too stable and has too low reactivity, so it usually reacts under high temperature and high pressure. The present invention adopts a high temperature solid phase method and is carried out under normal pressure.

[0014] Furthermore, the protective gas is argon or nitrogen.

[0015] Furthermore, the purity of the BaO, H3BO3, BN and Eu2O3 raw materials is 99.0%.

[0016] Furthermore, the grinding time of the BaO, H3BO3, BN and Eu2O3 raw materials is 15 to 30 minutes.

[0017] A sixth object of the present invention is to provide a method for preparing the above fluorescent ceramic sheet, comprising the following steps:

[0018] The phosphor powder is fully and evenly ground, and then pressed in a tablet press at a pressure of 250-350 MPa for 5-20 minutes to form a ceramic sheet, which is then placed in a tungsten crucible and covered with raw material powder, and transferred to a high-temperature tube furnace for sintering in a reducing atmosphere of a N2 / H2 mixed gas. It is sintered at 1200-1500°C in a vacuum for 2-10 hours, and then naturally cooled to room temperature to obtain an orange-red emitting nitrogen oxide ceramic sheet.

[0019] Furthermore, the grinding time of the phosphor powder is 5 to 20 hours.

[0020] Furthermore, the volume ratio of N2 to H2 in the above-mentioned N2 / H2 mixed gas is (7-10):1.

[0021] Furthermore, the heating rate of the above sintering is 5-10°C / min.

[0022] The beneficial effects of the present invention are:

[0023] The phosphor of the present invention is prepared by using Ba6B4O9N2 as the matrix material and adopting a high temperature solid phase method under normal pressure. It has a brand new structure and chemical composition. 2+ As an activation ion, the phosphor can be excited by near-ultraviolet and blue light, and its emission peak is at 620nm. It is an orange-red emitting phosphor and meets the current demand for red phosphors. The prepared fluorescent ceramic sheet emits bright red light under 400nm laser excitation. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a scanning electron microscope image of the Ba6B4O9N2 crystal prepared in Example 1 of the present invention;

[0025] Figure 2 The crystal structure diagram of Ba6B4O9N2 prepared in Example 1 of the present invention along the

[100] ,

[010] and

[001] directions;

[0026] Figure 3 X-ray diffraction pattern of single crystal data of Ba6B4O9N2 matrix prepared in Example 1 of the present invention;

[0027] Figure 4 The excitation and emission spectra of the orange-red emitting nitrogen oxide phosphor prepared in Example 2 of the present invention;

[0028] Figure 5 The photograph of the orange-red emitting oxynitride fluorescent ceramic sheet prepared in Example 3 of the present invention (top) and the photograph of the sheet excited by 400nm laser (bottom). DETAILED DESCRIPTION

[0029] The principles and features of the present invention are described below in conjunction with embodiments. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0030] Embodiment 1:

[0031] A preparation method of Ba6B4O9N2 crystal comprises the following steps:

[0032] According to the stoichiometric ratio of Ba6B4O9N2, BaO2.7599g, H3BO30.3710g and BN0.1340g with a purity of 99.9% were weighed in an argon-filled glove box, and fully mixed and ground in an agate mortar for 20 minutes. The evenly ground powder was placed in a tungsten crucible and sealed. The tungsten crucible was then placed in a high-temperature tube furnace and sintered in a reducing atmosphere of N2 / H2 (9:1). The sintering procedure was as follows: heating to 1250°C at a heating rate of 10°C / min, sintering at a constant temperature for 5h, then cooling to 1000°C at a rate of 5° / min, and then waiting for the temperature to drop to room temperature to obtain nitrogen oxide Ba6B4O9N2 crystals.

[0033] The Ba6B4O9N2 crystal obtained in Example 1 was subjected to scanning electron microscope micromorphology analysis. Figure 1 The crystal size is 20-50 μm, and the particles are blocky. The obtained crystals were tested by Rigaku single crystal instrument, and the obtained single crystal data were analyzed. The crystals belong to the orthorhombic system, and the unit cell parameters are Z = 6. The crystal structure consists of non-condensed triangular planar BO3 units, linear BN2 units and Ba 2+ Cationic composition, see Figure 2 The analyzed single crystal data were subjected to X-ray diffraction test, and the results are shown in Figure 3 . The pure phase of Ba6B4O9N2 was obtained by comparison with the crystallographic database card.

[0034] Embodiment 2:

[0035] A kind of Ba 5.97 B4O9N2:0.03Eu 2+ The preparation of phosphor includes the following steps:

[0036] According to Ba 5.97 B4O9N2:0.03Eu 2+According to the stoichiometric ratio, BaO2.7599g, H3BO30.3710g, BN0.1340g and Eu2O30.0317g with a purity of 99.9% were weighed in a glove box filled with argon, and fully mixed and ground in an agate mortar for 20 minutes. The evenly ground powder was placed in a tungsten crucible and sealed. The tungsten crucible was then placed in a high-temperature tube furnace and sintered in a reducing atmosphere of N2 / H2 (9:1). The sintering procedure was as follows: the temperature was increased to 1250°C at a heating rate of 10°C / min, sintered at a constant temperature for 5h, and then cooled naturally until it dropped to room temperature and fully ground to obtain the orange-red emitting nitrogen oxide phosphor Ba 5.97 B4O9N2:0.03Eu 2+ .

[0037] Excitation and emission spectra are shown in Figure 4 The excitation spectrum of the phosphor is in the range of 350 to 550 nm, the emission spectrum is in the range of 550 to 750 nm, and the main emission peak is at 620 nm, which is an orange-red emission.

[0038] Embodiment 3:

[0039] A kind of Ba 5.97 B4O9N2:0.03Eu 2+ The preparation of the fluorescent ceramic sheet includes the following steps:

[0040] Weigh 5g of synthetic Ba 5.97 B4O9N2:0.03Eu 2+ The powder was fully ground in a ball mill for about 10 hours. The ground powder was pressed in a tablet press at a pressure of 300 MPa for 10 minutes to form a ceramic sheet with a diameter of 10 mm and a thickness of 0.5 mm. The ceramic sheet was placed in a tungsten crucible and covered with unpressed powder. The tungsten crucible was then placed in a vacuum high-temperature tube furnace. The sintering process was carried out in a reducing atmosphere of N2 / H2 (9:1). The sintering procedure was as follows: the temperature was raised to 1300°C at a heating rate of 10°C / min and sintered for 3 hours, then naturally cooled to room temperature to obtain orange-red emitting nitrogen oxide Ba. 5.97 B4O9N2:0.03Eu 2+ The photo of the fluorescent ceramic sheet and the photo of it when excited by 400nm laser, such as Figure 5 Under the excitation of 400nm laser, the fluorescent ceramic emits bright red light.

[0041] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A Ba6B4O9N2 crystal, characterized in that: The crystal is an orthorhombic system, and the unit cell parameters Z=6, space group is P-4b2.

2. A phosphor, characterized in that: Ba6B4O9N2 crystal is used as the matrix material, and the chemical formula is Ba 6-X B4O9N2:xEu 2 + , where 0≤x≤6.

3. A fluorescent ceramic sheet, characterized in that: Prepared from the phosphor described in claim 2.

4. A method for preparing Ba6B4O9N2 crystals as claimed in claim 1, characterized in that: The steps include: According to the stoichiometric ratio of Ba6B4O9N2, weigh BaO, H3BO3, and BN raw materials under a protective gas atmosphere, and then mix and grind the raw materials evenly; put the ground powder into a crucible and seal it, then put the crucible into a high-temperature tube furnace, and sinter it in a reducing atmosphere of N2 / H2 at 1200-1650°C for 5-12 hours, then cool it to 900-1100°C, and wait until the temperature drops to room temperature to obtain nitrogen oxide Ba6B4O9N2 crystals.

5. A method for preparing the phosphor according to claim 2, characterized in that: The steps include: BaO, H3BO3, BN and Eu2O3 raw materials are weighed under a protective gas atmosphere, and then the raw materials are fully mixed and ground evenly; the ground mixture is placed in a crucible, packaged, and transferred to a high-temperature tube furnace, sintered in a reducing atmosphere of a N2 / H2 mixed gas at 1200-1650°C for 3-30 hours, and then naturally cooled to room temperature to obtain an orange-red emitting nitrogen oxide phosphor.

6. The preparation method according to claim 4 or 5, characterized in that: The protective gas is argon; the purity of the raw materials of BaO, H3BO3, BN, P3N5 and Eu2O3 is 99.0%; and the grinding time of the raw materials is 15 to 30 minutes.

7. A method for preparing a fluorescent ceramic sheet as claimed in claim 3, characterized in that: The steps include: The phosphor powder is fully and evenly ground, and then pressed in a tablet press at a pressure of 250-350 MPa for 5-20 minutes to form a ceramic sheet, which is then placed in a tungsten crucible and covered with raw material powder, and transferred to a vacuum high-temperature tube furnace for sintering in a reducing atmosphere of a N2 / H2 mixed gas. It is sintered at 1200-1500°C in vacuum for 2-10 hours, and then naturally cooled to room temperature to obtain an orange-red emitting nitrogen oxide ceramic sheet.

8. The method for preparing a fluorescent ceramic sheet according to claim 7, characterized in that: The grinding time of the phosphor powder is 5 to 20 hours.

9. The preparation method according to claim 4, 5 or 7, characterized in that: The volume ratio of N2 to H2 in the N2 / H2 mixed gas is (7-10):

1.

10. The preparation method according to claim 4, 5 or 7, characterized in that: The heating rate of the sintering is 5-10°C / min.

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