A green phosphor, its preparation method and application

Abstract

This invention belongs to the field of luminescent materials technology, and discloses a green phosphor, its preparation method, and its application. The green phosphor has the chemical formula CaY. 1‑x GaO4:xCe 3+ Wherein, 0.02 ≤ x ≤ 0.2. The green phosphor of this invention, due to its specific composition, can be used not only in non-contact optical temperature measurement but also in indoor lighting. When applied to optical temperature measurement, it offers advantages such as rapid response, high resolution, high sensitivity, high temperature resistance, and no need for direct contact with objects. Furthermore, when mixed with blue LED chips and commercially available red phosphor, it can be used as a warm white LED device, which features low cost, stable performance, and good luminous effect.

Description

Technical Field

[0001] This invention belongs to the field of luminescent materials technology, and specifically relates to a green phosphor, its preparation method, and its application. Background Technology

[0002] Phosphors have a wide range of applications, such as in LEDs or in temperature measuring devices.

[0003] In the existing technology, the temperature measurement devices cannot meet the requirements of high-precision measurement, and cannot simultaneously take into account both temperature measurement sensitivity and signal discrimination. Furthermore, most of the phosphors used for temperature measurement that utilize the optical properties of material fluorescence have low emission spectral bandwidth and exhibit narrow-band emission, making them difficult to apply in the field of LED lighting.

[0004] Existing white LEDs also have poor luminous performance.

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

[0006] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a green phosphor, its preparation method, and its application.

[0007] The green phosphor described in this invention can be used not only in non-contact optical temperature measurement but also in indoor lighting. When applied to optical temperature measurement, it offers advantages such as rapid response, high resolution, high sensitivity, high temperature resistance, and no need for direct contact with objects. Furthermore, when mixed with blue LED chips and commercially available red phosphor, it can be used as a warm white LED device, which is low in cost, stable in performance, and produces a warm white LED device with good luminous effect, for example, an Ra (color rendering index) of 76.8, a color temperature of 4143K, and CIE (chromaticity) coordinates of (0.369, 0.353).

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

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

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

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

[0012] The aforementioned green phosphor is a gallate phosphor.

[0013] Preferably, 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; more preferably, the green phosphor is excited by blue light, and the emission peak is located in the main 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 them.

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

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

[0017] (1) Weigh out calcium-containing compounds, yttrium-containing compounds, gallium-containing compounds and cerium-containing compounds and mix them to obtain a mixture;

[0018] (2) The mixture is calcined under the conditions 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 includes Y2O3.

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

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

[0023] Preferably, the calcium-containing compound, yttrium-containing compound, gallium-containing compound, and 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 includes carbon powder.

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

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

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

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

[0030] A thermometer comprising the aforementioned green fluorescent powder.

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

[0032] A lighting device comprising the aforementioned green phosphor.

[0033] Preferably, the lighting device includes LEDs.

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

[0035] The aforementioned LEDs can emit warm white light.

[0036] The above-mentioned lighting equipment 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 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. Furthermore, when mixed with blue light chips and commercial red phosphor, it can be used as a warm white LED device, which has the advantages of low cost, stable performance, and good luminous effect of the obtained warm white LED device, for example, Ra (color rendering index) of 76.8, color temperature of 4143K, and CIE (chromaticity) coordinates (0.369, 0.353).

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

[0040] (3) The green phosphor of this invention is prepared by high-temperature solid-state method with carbon powder reduction. The preparation process is safe and simple, the reaction conditions are easy to control, the finished product is obtained directly, the cost is low, the output is large, and there is no pollution. It is the best method for preparing Ce. 3+ A highly competitive method for doping phosphors.

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

[0042] (5) The green phosphor prepared by this 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 with commercial red phosphor and encapsulated to form a warm white LED device.

[0044] (7) The green phosphor prepared by the present invention is excited by blue light, and the emission peak is located in the main wavelength band of 508nm and 566nm. It has a characteristic spectrum of dual emission peaks and can be used to measure temperature by fluorescence intensity ratio technology. It can be applied in the field of non-contact optical temperature sensing. Attached Figure Description

[0045] Figure 1 XRD patterns of the green phosphors prepared in Examples 1-6;

[0046] Figure 2 The emission spectra of the green phosphors prepared in Examples 1-6 under 460 nm excitation are shown.

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

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

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

[0050] Figure 6 CaY prepared in Example 2 0.91 GaO4: 0.09Ce 3+ Relative sensitivity S r Relationship with temperature T. Detailed Implementation

[0051] To enable those skilled in the art to more clearly understand the technical solutions described in this invention, the following embodiments are provided for illustration. It should be noted that the following embodiments do not constitute a limitation on the scope of protection claimed by this invention.

[0052] Unless otherwise specified, the raw materials, reagents or devices used in the following examples are available from conventional commercial sources or can be obtained by existing known methods.

[0053] Example 1: Preparation of green phosphor

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

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

[0056] CaCO3, Y2O3, Ga2CO3, and CeO2 were ground in an agate mortar in a molar ratio of 1:0.9:1:0.1 for about 20 minutes to ensure thorough mixing. The mixture was then placed in a corundum crucible, which was placed inside a larger crucible containing carbon powder. The crucible was then placed in a muffle furnace (heating rate of 10 min / ℃ below 1000℃; heating rate of 2 min / ℃ above 1000℃) and calcined at 1250℃ for 4 hours. After cooling to room temperature, the mixture was removed, ground, and dispersed to obtain a green fluorescent powder (chemical formula CaY). 0.9 GaO4:0.1Ce 3+ ).

[0057] Example 2: Preparation of green phosphor

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

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

[0060] CaCO3, Y2O3, Ga2CO3, and CeO2 were ground in an agate mortar in a molar ratio of 1:0.91:1:0.09 for about 20 minutes to ensure thorough mixing. The mixture was then placed in a corundum crucible, which was placed inside a larger crucible containing carbon powder. The crucible was then placed in a muffle furnace (heating rate of 10 min / ℃ below 1000℃; heating rate of 2 min / ℃ above 1000℃) and calcined at 1300℃ for 4 hours. After cooling to room temperature, the mixture was removed, ground, and dispersed to obtain a green fluorescent powder (chemical formula CaY).0.91 GaO4: 0.09Ce 3 + ).

[0061] Example 3: Preparation of green phosphor

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

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

[0064] CaCO3, Y2O3, Ga2CO3, and CeO2 were ground in an agate mortar in a molar ratio of 1:0.93:1:0.07 for about 20 minutes to ensure thorough mixing. The mixture was then placed in a corundum crucible, which was placed inside a larger crucible containing carbon powder. The crucible was then placed in a muffle furnace (heating rate of 10 min / ℃ below 1000℃; heating rate of 2 min / ℃ above 1000℃) and calcined at 1350℃ for 4 hours. After cooling to room temperature, the mixture was removed, ground, and dispersed to obtain a green fluorescent powder (chemical formula CaY). 0.93 GaO4: 0.07Ce 3 + ).

[0065] Examples 4-6

[0066] Examples 4-6 describe the preparation of green phosphors using the method described in Example 2. The chemical formulas of the green phosphors corresponding to Examples 4-6 are CaY, respectively. 0.94 GaO4: 0.06Ce 3+ CaY 0.96 GaO4: 0.04Ce 3+ CaY 0.98 GaO4: 0.02Ce 3+ .

[0067] Product effectiveness test

[0068] Figure 1 XRD patterns of the green phosphors prepared in Examples 1-6; from Figure 1 ( Figure 1 In the figure, 2Theta (Degree) represents 2θ (degree), and "Intensity" represents intensity. It can be seen that the green phosphor prepared by this 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 phosphors prepared in Examples 1-6 under 460 nm excitation are shown; from Figure 2 ( Figure 2In this context, "Wavelength" represents wavelength, "Intensity" represents intensity, and λ... ex As can be seen from the excitation light, 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; from Figure 3 ( Figure 3 In this context, "Wavelength" represents the wavelength, "Normalized Intensity" represents the normalized intensity, and λ is the wavelength. ex Indicates excitation light, λ em As can be seen from the emitted light, under 460nm blue light excitation, the photoluminescence spectrum of the green phosphor exhibits a double emission peak, with 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 state was detected. 1 -5d 5 Several excitation bands in 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 fluorescent powder (commercial red fluorescent powder, containing Eu) 2+ Mix the ingredients according to a 2:1 mass ratio, add UV-curable adhesive, coat the mixture onto a 450nm blue LED chip, then irradiate it with a UV lamp to solidify it. Applying a 100mA current will produce a warm white LED. The emission spectrum and actual light emission diagram of the warm white LED are shown below. Figure 4 As shown. From Figure 4 ( Figure 4 In the diagram, "a" corresponds to the emission spectrum of the warm-light LED, "b" corresponds to the actual light emission diagram, "Wavelength" represents the wavelength, and "Intensity" represents the intensity. It can be seen that Ra (color rendering index) is 76.8, CCT (color temperature) is 4143K, and the light emission effect is good.

[0072] Figure 5 CaY prepared in Example 2 0.91 GaO4: 0.09Ce 3+ The fitted curve of the fluorescence intensity ratio; from Figure 5 (FIR(I 508 / I 566The expression represents the ratio of fluorescence intensity at 508 nm to fluorescence intensity at 566 nm. "Temperature" represents temperature, "Measured Date" represents the measured value, and "Fitted curve" represents the fitted curve. As can be seen from the expression, the fitted curve equation is y = 1.77778 - 0.00112x, and the correlation coefficient R0 is... 2 The value is 0.99066, which shows 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 A graph showing the relationship between temperature T and temperature. From... 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 this invention... 0.91 GaO4: 0.09Ce 3+ It is highly sensitive 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 of x is in the range of 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 peaks are 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 them.

5. The method for preparing the green phosphor according to any one of claims 1-4, characterized in that, Includes the following steps: (1) Weigh out calcium-containing compounds, yttrium-containing compounds, gallium-containing compounds and cerium-containing compounds and mix them to obtain a mixture; (2) The mixture is calcined under the conditions 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℃±100℃, and the calcination time is 1-4h.

9. A thermometer, characterized in that, Includes the green phosphor according to any one of claims 1-4.

10. A lighting device, characterized in that, Includes the green phosphor according to any one of claims 1-4.

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