Fluorescent powder as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of fluorescent materials, and discloses fluorescent powder as well as a preparation method and application thereof. The chemical formula of the fluorescent powder is Ba < 2.92 > Mg < 0.08 > BP3O12: 12% Eu < 2 + > / Eu < 3 + >. The fluorescent powder not only can be applied to the field of optical temperature measurement, but also can be applied to the field of white light LED illumination. When being applied to optical temperature measurement, the optical temperature sensor has the advantages of quick effect, high resolution, high sensitivity, high temperature resistance, no need of direct contact with an object and the like, and can still ensure high discrimination degree of signals while performing high-sensitivity test. The fluorescent powder can be used as a white light LED device after being mixed with commercial fluorescent powder, white light emitted by the prepared LED device is high in color rendering index and high in luminous efficiency, and the light color does not change along with the change of current and temperature and is stable.

Description

Technical Field

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

[0002] Within a certain temperature range, certain optical properties of rare earth phosphors, such as peak position, fluorescence intensity ratio (FIR), spectral linewidth, and fluorescence lifetime decay, change regularly with temperature changes and are monotonic and repeatable. Changes in these optical properties can be used to calibrate temperature. Among them, the self-reference optical temperature measurement technology based on FIR technology has attracted the attention of many researchers due to its unique advantages in non-contact, fast response, high sensitivity, etc., and it is also beneficial for working in harsh environments or detecting fast-moving objects. This method can effectively avoid many defects of traditional contact temperature measurement methods, such as low resolution and long response time. However, the traditional technology of optical temperature measurement through thermal coupling energy level fluorescence intensity ratio technology has strict limitations. The interval between the thermal coupling energy levels of the activated ions must be between 200cm -1 ~2000cm -1 Therefore, the temperature measurement sensitivity obtained by this technology cannot meet the requirements of high-precision measurement, and it is also impossible to take into account both temperature measurement sensitivity and signal discrimination. In addition, most of the phosphors used in temperature measurement using the fluorescence optical properties of materials have low emission spectrum bandwidth, narrow-band emission, low luminous efficiency, and unstable light color, so they are difficult to be applied in the field of LED lighting.

[0003] However, the temperature measurement sensitivity, response speed and resolution of the phosphor in the prior art need to be further improved.

[0004] Therefore, there is an urgent need to provide a new phosphor which has the advantages of rapid effect, high resolution, high sensitivity, and further high luminous efficiency and stable light color. Summary of the invention

[0005] The present invention aims to solve at least one of the technical problems existing in the above-mentioned prior art. To this end, the present invention proposes a phosphor and a preparation method and application thereof. The phosphor of the present invention has a wide range of uses and can achieve cross-field integration. It can be used not only in the field of optical temperature measurement, but also in the field of white light LED lighting. When applied to optical temperature measurement, it has the advantages of fast effect, high resolution, high sensitivity, high temperature resistance and no need for direct contact with objects. It can still ensure high discrimination of signals while performing high-sensitivity tests. And after mixing with commercial phosphors, it can be used as a white light LED device. The white light emitted by the prepared LED device has a high color rendering index, high luminous efficiency, and the light color does not change with changes in current and temperature, and the light color is stable.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] A first aspect of the present invention provides a phosphor.

[0008] Specifically, a phosphor having a chemical formula of Ba 2.92 Mg 0.08 BP3O 12 :12%Eu 2+ / Eu 3+ .

[0009] 12% represents Eu 2+ and Eu 3+ The relative molecular mass accounts for Ba 2.92 Mg 0.08 BP3O 12 The percentage of relative molecular mass.

[0010] Preferably, the Ba 2.92 Mg 0.08 BP3O 12 Belongs to the hexagonal crystal system.

[0011] Preferably, when the phosphor is excited by ultraviolet or near-ultraviolet light, the emission peaks are located at 515 nm and 685 nm.

[0012] A second aspect of the present invention provides a method for preparing a phosphor.

[0013] Specifically, a method for preparing a phosphor comprises the following steps:

[0014] Barium salt, magnesium salt, phosphoric acid and / or phosphate, boric acid and / or borate, and europium oxide are mixed and calcined in a carbon reducing atmosphere to obtain the phosphor.

[0015] The above synthesis method is a high temperature solid phase method.

[0016] Preferably, the barium salt includes at least one of barium carbonate and barium bicarbonate.

[0017] Preferably, the magnesium salt includes at least one of magnesium carbonate and magnesium bicarbonate.

[0018] Preferably, the phosphate comprises diammonium phosphate.

[0019] Preferably, the borate comprises ammonium borate.

[0020] Preferably, the molar ratio of the barium salt, magnesium salt, phosphoric acid and / or phosphate, boric acid and / or borate, and europium oxide is 2.92:0.08:3:(1-1.5):0.12, and more preferably 2.92:0.08:3:(1.25-1.5):0.12. The role of the excess boric acid is to make up for the loss caused by the volatilization of boric acid during high-temperature calcination.

[0021] Preferably, the mixing is carried out by grinding.

[0022] Preferably, the calcination temperature is 900-1050° C., and the calcination time is 4-6 hours; further preferably, the calcination temperature is 950-1050° C., and the calcination time is 5-6 hours.

[0023] The third aspect of the present invention provides the application of the above phosphor.

[0024] A temperature measuring device comprises the above-mentioned fluorescent powder.

[0025] An LED device comprises the above-mentioned phosphor.

[0026] Preferably, the LED device is a white light LED device.

[0027] Preferably, the white light LED device has a color rendering index Ra of 80-80.2, a color temperature of 5678-5680K, and a CIE coordinate of (0.32, 0.33).

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0029] (1) The phosphor of the present invention has a wide range of uses and can achieve cross-domain integration. It can be used not only in the field of optical temperature measurement, but also in the field of white light LED lighting. When applied to optical temperature measurement, it has the advantages of fast effect, high resolution, high sensitivity, high temperature resistance, and no need for direct contact with objects. It can still ensure high signal discrimination while performing high-sensitivity tests. And after mixing with commercial phosphors, it can be used as a white light LED device. The white light emitted by the prepared LED device has a high color rendering index, high luminous efficiency, and the light color does not change with changes in current and temperature, and the light color is stable.

[0030] (2) The present invention proposes a method of doping a multivalent rare earth luminescent ion in a borophosphate matrix. It has the characteristics of high bandwidth, high half-peak width, etc., spanning multiple light color bands. After LED device packaging, the red light, blue light and yellow light are evenly distributed, and the performance is excellent, which can be used in the field of white light LED lighting; under different ultraviolet light excitation, it can also be used to establish Eu 2+ / Eu 3+ The standard curve between the corresponding characteristic emission peak intensity ratio and temperature accurately reflects the change of ambient temperature.

[0031] (3) The fluorescent material of the present invention is an optical temperature measuring material, which is synthesized by a high temperature solid phase method in a carbon reduction atmosphere. 3+ Ion self-reduction to Eu 2+ ions, the preparation process is safe and simple, the synthesis temperature is low, and the reaction conditions are easy to control.

[0032] (4) The fluorescent material prepared by the present invention has high phase purity, is completely consistent with the standard card, has no impurities, and has good crystallinity.

[0033] (5) The fluorescent material prepared by the present invention is non-toxic, harmless, has stable physical and chemical properties, and will not react with oxygen, carbon dioxide and water in the air when exposed to the air for a long time.

[0034] (6) The fluorescent material prepared by the present invention can be excited by ultraviolet or near-ultraviolet light, and the emission peaks are located in the yellow-green light band with a main wavelength of 515nm and the red light band of 685nm, and have good distinguishability.

[0035] (7) The fluorescent material prepared by the present invention has good temperature sensitivity, high temperature measurement sensitivity, and the maximum absolute sensitivity Sa is 0.77K -1 . BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 The emission spectra of the phosphors of Example 1 and Comparative Examples 1-5 are shown;

[0037] Figure 2 is the XRD pattern of the phosphor of Example 1;

[0038] Figure 3 is the room temperature emission spectrum of the phosphor of Example 1;

[0039] Figure 4 The actual picture of the LED device packaged with the phosphor of Example 1, the scene picture when powered on, and the CIE coordinate diagram;

[0040] Figure 5 This is the electroluminescence spectrum of the phosphor of Example 1 after LED device packaging;

[0041] Figure 6 This is the temperature-dependent spectrum of the phosphor of Example 1;

[0042] Figure 7 is a fitting diagram of the fluorescence intensity ratio of the phosphor in Example 1 and the temperature T;

[0043] Figure 8 is the absolute sensitivity S of the phosphor in Example 1 a curve. DETAILED DESCRIPTION

[0044] In order to make the technical scheme of the present invention more clearly understood by those skilled in the art, the following embodiments are listed for illustration. It should be pointed out that the following embodiments do not limit the protection scope of the present invention.

[0045] Unless otherwise specified, the raw materials, reagents or devices used in the following examples can be obtained from conventional commercial sources or by existing known methods.

[0046] Example 1: Ba 2.92 Mg 0.08 BP3O 12 :12%Eu 2+ / Eu 3+ Preparation of phosphor

[0047] A phosphor with the chemical formula Ba 2.92 Mg 0.08 BP3O 12 :12%Eu 2+ / Eu 3+ . "Eu 2+ / Eu 3+ "Indicates that it also contains Eu 2+ and Eu 3+ .

[0048] A method for preparing a fluorescent powder comprises the following steps:

[0049] Weigh 2.92mmol of barium carbonate, 0.08mmol of magnesium carbonate, 3mmol of ammonium dihydrogen phosphate, 1.25mmol of boric acid, and 0.12mmol of europium oxide Eu2O3, and mix the weighed raw materials evenly in an agate mortar under a carbon reducing atmosphere. Grind them thoroughly for 20 minutes, then put them in a corundum crucible, put them in a muffle furnace, heat them to 1000℃ at a heating rate of 5min / ℃, and then calcine them at 1000℃ for 6 hours. After cooling to room temperature, take them out, grind and disperse them to obtain the phosphor.

[0050] Comparative Example 1

[0051] Compared with Example 1, the difference of Comparative Example 1 is that the amount of barium carbonate used is 3 mmol, and the amount of magnesium carbonate used is 0 mmol, and the chemical formula is Ba3BP3O 12 :12%Eu 2+ / Eu 3+ of phosphor.

[0052] Comparative Example 2

[0053] Compared with Example 1, the difference in Comparative Example 2 is that the amount of barium carbonate used is 2.98 mmol, and the amount of magnesium carbonate used is 0.02 mmol, and the chemical formula is Ba2.98 Mg 0.02 BP3O 12 :12%Eu 2+ / Eu 3+ of phosphor.

[0054] Comparative Example 3

[0055] Compared with Example 1, the difference in Comparative Example 3 is that the amount of barium carbonate used is 2.96 mmol, and the amount of magnesium carbonate used is 0.04 mmol, and the chemical formula is Ba 2.96 Mg 0.04 BP3O 12 :12%Eu 2+ / Eu 3+ of phosphor.

[0056] Comparative Example 4

[0057] Compared with Example 1, the difference in Comparative Example 4 is that the amount of barium carbonate used is 2.94 mmol, and the amount of magnesium carbonate used is 0.06 mmol, and the chemical formula is Ba 2.94 Mg 0.06 BP3O 12 :12%Eu 2+ / Eu 3+ of phosphor.

[0058] Comparative Example 5

[0059] Compared with Example 1, the difference in Comparative Example 5 is that the amount of barium carbonate used is 2.90 mmol, and the amount of magnesium carbonate used is 0.10 mmol, and the chemical formula is Ba 2.90 Mg 0.10 BP3O 12 :12%Eu 2+ / Eu 3+ of phosphor.

[0060] Comparative Example 6

[0061] Compared with Example 1, the only difference of Comparative Example 6 is that the magnesium carbonate in the raw material is replaced by sodium carbonate, potassium carbonate and aluminum carbonate in equimolar amounts, respectively, and no phosphor can be obtained.

[0062] Product effect testing

[0063] from Figure 1 (“Wavelength” means wavelength, “Intensity” means intensity) It can be seen that the phosphors prepared in Example 1 and Comparative Examples 1-5 have the highest luminous intensity under different element ratios, while the luminous intensity of the comparative examples is significantly reduced. The product of Comparative Example 6 cannot exist stably due to the substitution of non-conservative charge.

[0064] Figure 2 is the XRD diagram of the phosphor of Example 1. Figure 2 (“Intensity” means intensity, “2-Theta (degree)” means diffraction angle, the unit is degree) It can be seen that the diffraction peak of the phosphor corresponds to the standard card (PDF#89-7583), and no impurity phase is generated.

[0065] from Figure 3 (“Wavelength” means wavelength, “Intensity” means intensity) It can be seen that under the excitation of 365nm ultraviolet light, the phosphor of Example 1 produces a high-bandwidth emission peak with a maximum peak of 515nm and a half-peak width of 150nm, wherein the emission peak at 515nm comes from Eu 2+ Ion 5d-4f energy level transition.

[0066] Figure 4 (a) is a real picture of the LED device packaged with the phosphor of Example 1 according to the conventional method, (b) is a scene picture when the power is turned on, and (c) is a CIE coordinate diagram. It can be seen from the figure that after the phosphor of Example 1 is packaged into an LED, the light color is soft and bright, the color rendering index Ra is excellent at 80.2, the color temperature is 5680K, and the CIE coordinates are (0.3286, 0.3337) close to white light (0.33, 0.33).

[0067] Figure 5 This is the electroluminescence spectrum of the phosphor in Example 1 after LED device packaging. Figure 5 (“Wavelength” means wavelength, “Relative Spectrum” means relative spectrum) It can be seen that the red, yellow and green light parts have obvious and similar proportions in the emission spectrum, which conforms to the RGB three-primary color principle and can be combined into white light. This shows that the phosphor of Example 1 has excellent performance as a white light LED device and has great application prospects.

[0068] Under 380nm excitation light, the emission peaks at 588nm, 612nm, 653nm and 685nm in the emission spectrum come from Eu 3+ ion 5 D0- 7 F J (J = 1, 2, 3, 4) energy level transitions further prove the presence of Eu in the phosphor of Example 1. 2+ and Eu 3+ ion.

[0069] Figure 6 is the temperature spectrum (303K-523K) of the phosphor of Example 1, from Figure 6(“Wavelength” means wavelength, “Intensity” means intensity) It can be seen that the phosphor of Example 1 has two strong emission peaks at 515nm and 685nm in the range of 303K-523K under the excitation of 380nm excitation light, and the signal peak (I 515 and I 685 ) wavelength interval is 170nm, with excellent signal discrimination, effectively avoiding mutual interference of monitoring signals. As the temperature increases from 303K to 523K, the wavelength at 685nm (Eu 2+ :5d-4f) at the emission peak intensity I 515 (taking the integrated intensity of 515nm-575nm) decreased significantly, while 685nm (Eu 3+ : 5 D0- 7 The emission peak intensity I 685 (taking the integrated intensity of 670nm-700nm) is almost unchanged, so Eu 2+ and Eu 3+ Different fluorescence thermal response characteristics for temperature monitoring.

[0070] Figure 7 is the fluorescence intensity ratio of the phosphor in Example 1 (Eu 2+ :5d-4f / Eu 3+ : 5 D0- 7 F4) and temperature T, from Figure 7 (“Temperature” means temperature, FIR means fluorescence intensity ratio, “Measured Data” means measured data, and “Fitting Curve” means fitting curve) 2+ :5d-4f / Eu 3+ : 5 D0- 7 F4) has a good fit with temperature T, FIR = -5.8268exp(T / 62.0368)+1.6479, R 2 The value is 0.965.

[0071] Figure 8 (“Temperature” means temperature) is the absolute sensitivity S of the phosphor in Example 1 a Curve, it is calculated that the maximum absolute sensitivity Sa (max.) of the phosphor in Example 1 is 0.77K -1 , indicating that the phosphor of Example 1 has a high temperature measurement sensitivity and can be applied to the field of non-contact optical temperature measurement.

[0072] Application Examples

[0073] A temperature measuring device comprises the phosphor of embodiment 1.

Claims

1. A phosphor, characterized in that: Its chemical formula is Ba 2.92 Mg 0.08 BP3O 12 :12%Eu 2+ / Eu 3+ .

2. The phosphor according to claim 1, characterized in that: The Ba 2.92 Mg 0.08 BP3O 12 Belongs to the hexagonal crystal system.

3. The phosphor according to claim 1, characterized in that: When the fluorescent powder is excited by ultraviolet or near-ultraviolet light, the emission peaks are located at 515nm and 685nm.

4. The method for preparing the phosphor according to any one of claims 1 to 3, characterized in that: The following steps are involved: Barium salt, magnesium salt, phosphoric acid and / or phosphate, boric acid and / or borate, and europium oxide are mixed and calcined in a carbon reducing atmosphere to obtain the phosphor.

5. The preparation method according to claim 4, characterized in that: The barium salt includes at least one of barium carbonate and barium bicarbonate.

6. The preparation method according to claim 4, characterized in that: The magnesium salt includes at least one of magnesium carbonate and magnesium bicarbonate; and / or, the phosphate includes ammonium dihydrogen phosphate; and / or, the borate includes ammonium borate.

7. The preparation method according to claim 4, characterized in that: The molar ratio of the barium salt, the magnesium salt, the phosphoric acid and / or the phosphate, the boric acid and / or the borate, and the europium oxide is 2.92:0.08:3:(1-1.5):0.

12.

8. The preparation method according to claim 4, characterized in that: The calcination temperature is 900-1050° C., and the calcination time is 4-6 hours.

9. A temperature measuring device, characterized in that: The phosphor comprises the phosphor described in any one of claims 1 to 3.

10. An LED device, characterized in that: The phosphor comprises the phosphor described in any one of claims 1 to 3.

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