Green fluorescent powder as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of luminescent materials, and discloses green fluorescent powder as well as a preparation method and application thereof. The chemical formula of the green fluorescent powder is CaY (1-x) GaO4: xCe < 3 + >, and x is more than or equal to 0.02 and less than or equal to 0.2. Due to the specific composition, the green fluorescent powder disclosed by the invention not only can be used in the field of non-contact optical temperature measurement, but also can be used in the field of indoor 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 after being mixed with a blue light chip and commercial red fluorescent powder, the light-emitting material can be used as a warm white light LED device, and has the advantages of low cost and stable performance, and the obtained warm white light LED device has a good light-emitting effect.

Description

Technical Field

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

[0002] Phosphors are widely used, for example, in LEDs or in temperature measuring devices.

[0003] In the prior art, the temperature measurement sensitivity of the devices used for temperature measurement 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 for temperature measurement using the fluorescent optical properties of materials are difficult to apply in the field of LED lighting because of their low emission spectrum bandwidth and narrow-band emission.

[0004] The existing white light LED also has poor luminous performance.

[0005] Therefore, there is an urgent need to provide a new phosphor to solve the problems of temperature measurement and white light. Summary of the invention

[0006] 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 provides a green phosphor and a preparation method and application thereof.

[0007] The green phosphor of the present invention can be used not only in the field of non-contact optical temperature measurement, but also in the field of indoor lighting. When used in 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. And after being mixed with a blue light chip and commercial red phosphor, it can be used as a warm white light LED device, which has low cost, stable performance, and good luminous effect of the warm white light LED device, for example, Ra (color rendering index) is 76.8, color temperature is 4143K, and CIE (chromaticity) coordinates are (0.369, 0.353).

[0008] A first aspect of the present invention provides a green phosphor.

[0009] Specifically, a green phosphor with a chemical formula of CaY 1-x GaO4:xCe 3+ , where 0.02≤x≤0.2.

[0010] Preferably, the value range of x is 0.02≤x≤0.1.

[0011] x means Ce 3+ The mole fraction of CaYGaO4.

[0012] The green phosphor mentioned above is a gallate phosphor.

[0013] Preferably, the green phosphor is excited by blue light, and the emission peak is located in the dominant wavelength bands of 505-508nm and 564-566nm; further preferably, the green phosphor is excited by blue light, and the emission peak is located in the dominant wavelength bands of 508nm and 566nm.

[0014] Preferably, the chemical formula of the green phosphor includes CaY 0.9 GaO4:0.1Ce 3+ , CaY 0.91 GaO4:0.09Ce 3+ , CaY 0.93 GaO4:0.07Ce 3+ , CaY 0.94 GaO4:0.06Ce 3+ , CaY 0.96 GaO4:0.04Ce 3+ , CaY 0.98 GaO4:0.02Ce 3+ At least one of .

[0015] A second aspect of the present invention provides a method for preparing a green phosphor.

[0016] Specifically, a method for preparing green phosphor comprises the following steps:

[0017] (1) weighing a calcium-containing compound, a yttrium-containing compound, a gallium-containing compound, and a cerium-containing compound and mixing them to obtain a mixture;

[0018] (2) calcining the mixture in the presence of a reducing agent to obtain the green phosphor.

[0019] Preferably, the calcium-containing compound includes at least one of CaCO3, CaCl2, and CaO.

[0020] Preferably, the yttrium-containing compound comprises Y2O3.

[0021] Preferably, the gallium-containing compound includes at least one of Ga2CO3 and Ga2O3.

[0022] Preferably, the cerium-containing compound comprises CeO2.

[0023] Preferably, the calcium-containing compound, the yttrium-containing compound, the gallium-containing compound and the cerium-containing compound are mixed and then ground.

[0024] Preferably, the weight ratio of the calcium-containing compound, the yttrium-containing compound, and the gallium-containing compound is 1:(1-x):(0.5-1.5), and more preferably 1:(1-x):1.

[0025] Preferably, the reducing agent comprises carbon powder.

[0026] Preferably, the calcination temperature is 1300°C±100°C, and the calcination time is 1-4h. More preferably, the calcination temperature is 1300°C±50°C, and the calcination time is 3-4h.

[0027] Preferably, during the calcination process, the heating rate is 1-15°C / min, more preferably 2-15°C / min.

[0028] Preferably, during the calcination process, when the temperature is below 1000°C, the temperature is increased at a rate of 8-15°C / min, and when the temperature is above 1000°C, the temperature is increased at a rate of 2-5°C / min.

[0029] A third aspect of the present invention provides an application of a green phosphor.

[0030] A thermometer comprises the green fluorescent powder.

[0031] Preferably, the thermometer is a non-contact thermometer.

[0032] A lighting device comprises the green fluorescent powder.

[0033] Preferably, the lighting device comprises an LED.

[0034] Preferably, the LED also includes red phosphor and a blue LED chip.

[0035] The above-mentioned LED can emit warm white light.

[0036] The above lighting device can be used for indoor or outdoor lighting.

[0037] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0038] (1) The green phosphor of the present invention, due to its specific composition, can be used not only in the field of non-contact optical temperature measurement, but also in the field of indoor lighting. When used in 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. And after mixing with a blue light chip and commercial red phosphor, it can be used as a warm white light LED device, which has low cost, stable performance, and good luminous effect of the warm white light LED device, for example, Ra (color rendering index) is 76.8, color temperature is 4143K, and CIE (chromaticity) coordinates are (0.369, 0.353).

[0039] (2) The green-light gallate phosphor provided by the present invention can be effectively excited by blue light.

[0040] (3) The green phosphor of the present invention adopts a high-temperature solid phase method and carbon powder reduction. The preparation process is safe and simple, the reaction conditions are easy to control, and the finished product is directly obtained. The cost is low, the yield is large, and there is no pollution. 3+ A competitive approach to doping phosphors.

[0041] (4) The green phosphor prepared by the present invention is non-toxic, pollution-free and has high physical and chemical stability.

[0042] (5) The green phosphor prepared by the present invention has high phase purity, is completely consistent with the standard card, has no impurities, and has good crystallinity.

[0043] (6) The green phosphor prepared by the present invention can be mixed and packaged with commercial red phosphor to form a warm white light LED device.

[0044] (7) The green phosphor prepared by the present invention is excited by blue light, and its emission peaks are located in the main wavelength bands of 508nm and 566nm. It has a characteristic spectrum with double emission peaks, and can use fluorescence intensity ratio technology to measure temperature, which is applied in the field of non-contact optical temperature sensing. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 XRD diagram of the green phosphor prepared in Example 1-6;

[0046] Figure 2 The emission spectrum of the green phosphor prepared in Example 1-6 under 460nm excitation;

[0047] Figure 3 CaY prepared in Example 2 0.91 GaO4:0.09Ce 3+ Normalized excitation and emission plots of ;

[0048] Figure 4 CaY prepared in Example 2 0.91 GaO4:0.09Ce 3+ The emission spectrum and actual luminescence image of the warm light LED prepared by coating the blue light LED chip with commercial red phosphor;

[0049] Figure 5 CaY prepared in Example 2 0.91 GaO4:0.09Ce 3+ The fitting curve diagram of the fluorescence intensity ratio;

[0050] Figure 6 CaY prepared in Example 2 0.91 GaO4:0.09Ce 3+ Relative sensitivity S r The relationship diagram with temperature T. DETAILED DESCRIPTION

[0051] 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.

[0052] 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.

[0053] Example 1: Preparation of green phosphor

[0054] A green phosphor with the chemical formula of CaY 0.9 GaO4:0.1Ce 3+ 0.1 means Ce 3+ The mole fraction of CaYGaO4.

[0055] A method for preparing green phosphor comprises the following steps:

[0056] CaCO3, Y2O3, Ga2CO3, and CeO2 were ground in an agate mortar at a molar ratio of 1:0.9:1:0.1 for about 20 minutes to fully mix them, and then placed in a corundum crucible. The corundum crucible was placed in a large crucible filled with carbon powder, and then placed in a muffle furnace (below 1000°C, the heating rate was 10min / °C; above 1000°C, the heating rate was 2min / °C), calcined at 1250°C for 4h, and then cooled to room temperature and taken out, and ground and dispersed to obtain a green phosphor (chemical formula CaY 0.9 GaO4:0.1Ce 3+ ).

[0057] Example 2: Preparation of green phosphor

[0058] A green phosphor with the chemical formula of CaY 0.91 GaO4:0.09Ce 3+ .

[0059] A method for preparing green phosphor comprises the following steps:

[0060] CaCO3, Y2O3, Ga2CO3, and CeO2 were ground in an agate mortar at a molar ratio of 1:0.91:1:0.09 for about 20 minutes to fully mix them, and then placed in a corundum crucible. The corundum crucible was placed in a large crucible filled with carbon powder, and then placed in a muffle furnace (below 1000°C, the heating rate was 10min / °C; above 1000°C, the heating rate was 2min / °C), calcined at 1300°C for 4h, and then cooled to room temperature and taken out, and ground and dispersed to obtain a green phosphor (chemical formula CaY0.91 GaO4:0.09Ce 3 + ).

[0061] Example 3: Preparation of green phosphor

[0062] A green phosphor with the chemical formula of CaY 0.93 GaO4:0.07Ce 3+ .

[0063] A method for preparing green phosphor comprises the following steps:

[0064] CaCO3, Y2O3, Ga2CO3, and CeO2 were ground in an agate mortar at a molar ratio of 1:0.93:1:0.07 for about 20 minutes to fully mix them, and then placed in a corundum crucible. The corundum crucible was placed in a large crucible filled with carbon powder, and then placed in a muffle furnace (below 1000°C, the heating rate was 10min / °C; above 1000°C, the heating rate was 2min / °C), calcined at 1350°C for 4h, and then cooled to room temperature and taken out, and ground and dispersed to obtain a green phosphor (chemical formula CaY 0.93 GaO4:0.07Ce 3 + ).

[0065] Embodiment 4-6

[0066] Example 4-6: Green phosphors were prepared by referring to the method of Example 2. The chemical formulas of the green phosphors corresponding to Examples 4-6 are: CaY 0.94 GaO4:0.06Ce 3+ , CaY 0.96 GaO4:0.04Ce 3+ , CaY 0.98 GaO4:0.02Ce 3+ .

[0067] Product effect testing

[0068] Figure 1 The XRD patterns of the green phosphors prepared in Examples 1-6 are as follows; Figure 1 ( Figure 1 2Theta (Degree) means 2θ (degree), and “Intensity” means intensity) It can be seen that the green phosphor prepared by the present invention has high phase purity, is completely consistent with the standard card, has no impurities, and has good crystallinity.

[0069] Figure 2 The emission spectra of the green phosphor prepared in Example 1-6 under 460nm excitation; Figure 2 ( Figure 2"Wavelength" refers to wavelength, "Intensity" refers to intensity, and λ ex represents excitation light), it can be seen that the green phosphor can be excited by blue light, and the emission peaks are located in the main wavelength bands of 505-508nm and 564-566nm.

[0070] Figure 3 CaY prepared in Example 2 0.91 GaO4:0.09Ce 3+ Normalized excitation and emission plots of Figure 3 ( Figure 3 "Wavelength" means wavelength, "Normalized Intensity" means normalized intensity, and λ ex represents the excitation light, λ em It can be seen that under the excitation of 460nm blue light, the photoluminescence spectrum of the green phosphor shows a double emission peak, with the maximum emission peaks at 508nm and 566nm respectively. By monitoring the maximum emission at 508nm, the transition of electrons from the 4f ground state to the 5d 1 -5d 5 Several excitation bands of the excited state. The strongest excitation peak is in the blue light region, covering the emission spectrum of commercial LEDs.

[0071] The CaY prepared in Example 2 0.91 GaO4:0.09Ce 3+ With red phosphor (commercial red phosphor, containing Eu 2+ ) are mixed (according to the mass ratio of 2:1), and then mixed with UV curing glue, coated on the 450nm blue light chip, and then irradiated with UV lamp to solidify it, and connected with 100mA current, a warm white light LED can be obtained. The emission spectrum of the warm light LED and the actual luminescence diagram are shown in the figure. Figure 4 As shown. Figure 4 ( Figure 4 "a" corresponds to the warm light LED emission spectrum, "b" corresponds to the actual luminous graph, "Wavelength" indicates wavelength, and "Intensity" indicates intensity). It can be seen that the Ra (color rendering index) is 76.8, the CCT (color temperature) is 4143K, and the luminous effect is good.

[0072] Figure 5 CaY prepared in Example 2 0.91 GaO4:0.09Ce 3+ The fitting curve of the fluorescence intensity ratio of Figure 5 (FIR(I 508 / I 566) represents the ratio of the fluorescence intensity at 508 nm to the fluorescence intensity at 566 nm, "Temperature" represents the temperature, "Measured Date" represents the measured value, and "Fitted curve" represents the fitted curve. It can be seen that the fitting curve equation is y=1.77778-0.00112x, and the correlation coefficient R 2 It is 0.99066. It can be seen that the fluorescence intensity ratio has a good linear correlation with temperature. Sa represents the absolute sensitivity.

[0073] Figure 6 CaY prepared in Example 2 0.91 GaO4:0.09Ce 3+ Relative sensitivity S r The relationship between temperature and temperature T (“Temperature” means temperature). Figure 6 It can be seen that the relative sensitivity S r Maximum value (S r (max.)) is 0.0906%K -1 It can be seen that the CaY prepared by the present invention 0.91 GaO4:0.09Ce 3+ High sensitivity to temperature.

Claims

1. A green phosphor, characterized in that: Its chemical formula is CaY 1-x GaO4:xCe 3+ , where 0.02≤x≤0.

2.

2. The green phosphor according to claim 1, characterized in that: The value range of x is 0.02≤x≤0.

1.

3. The green phosphor according to claim 1, characterized in that: The green phosphor is excited by blue light, and the emission peak is located in the main wavelength bands of 505-508nm and 564-566nm.

4. The green phosphor according to claim 1, characterized in that: The chemical formula of the green phosphor includes CaY 0.9 GaO4:0.1Ce 3+ , CaY 0.91 GaO4:0.09Ce 3+ , CaY 0.93 GaO4:0.07Ce 3+ , CaY 0.94 GaO4:0.06Ce 3+ , CaY 0.96 GaO4:0.04Ce 3+ , CaY 0.98 GaO4:0.02Ce 3+ At least one of .

5. The method for preparing the green phosphor according to any one of claims 1 to 4, characterized in that: The following steps are involved: (1) weighing a calcium-containing compound, a yttrium-containing compound, a gallium-containing compound, and a cerium-containing compound and mixing them to obtain a mixture; (2) calcining the mixture in the presence of a reducing agent to obtain the green phosphor.

6. The preparation method according to claim 5, characterized in that: The calcium-containing compound includes at least one of CaCO3, CaCl2, and CaO; and / or the yttrium-containing compound includes Y2O3; and / or the gallium-containing compound includes at least one of Ga2CO3 and Ga2O3; and / or the cerium-containing compound includes CeO2.

7. The preparation method according to claim 5, characterized in that: The weight ratio of the calcium-containing compound, the yttrium-containing compound and the gallium-containing compound is 1:(1-x):(0.5-1.5).

8. The preparation method according to claim 5, characterized in that: The calcination temperature is 1300°C±100°C, and the calcination time is 1-4h.

9. A thermometer, characterized in that: The invention comprises the green phosphor as described in any one of claims 1 to 4.

10. A lighting device, characterized in that: The invention comprises the green phosphor as described in any one of claims 1 to 4.

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