LED phosphor and its preparation method and application

Abstract

The present invention discloses an LED fluorescent powder and a preparation method and application thereof. The chemical formula of the fluorescent powder is: NaLiZnS2:xMn 2+ ; Wherein 0.05≤x≤0.5. The phosphor provided by the present invention has a wide excitation band of 250-550nm and a deep red emission band of 600-800nm, and can be applied to plant growth LED lamps. The preparation process of the phosphor in the technical solution is simple, the synthesis temperature is low, and the physical and chemical properties are stable. The rich red light component is beneficial to plant growth and has a high application prospect.

Description

Technical Field

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

[0002] As the energy supply source for plant photosynthesis, light has always attracted extensive attention from academic researchers. In recent years, scholars have devoted themselves to studying the effects of different light qualities on plant growth, thereby analyzing the spectral composition of different light receptor absorption spectra to find luminescent materials whose emission spectra match the light required for plant growth, so as to achieve the purpose of improving photosynthesis efficiency. Traditional agriculture faces harsh environments such as frost, cloudy, drought and heavy rain, resulting in a decline in yield and failure to meet people's needs. In recent years, indoor plant cultivation has attracted widespread attention to create a suitable and stable growth environment for plants. Light source is a necessary condition for all plant growth processes, including branching, flowering and fruiting. Light energy can be converted into chemical energy through photosynthesis of plant pigments. Chlorophyll A, chlorophyll B, phytochrome PR and phytochrome PFR are the four main plant pigments, which mainly absorb blue light (400-500nm), red light (600-700nm) and far-red light (700-780nm).

[0003] Traditional indoor plant cultivation light sources include incandescent lamps, high-voltage halogen lamps and xenon lamps, which have disadvantages such as high energy consumption, short life and spectrum mismatch. Therefore, phosphor-converted light-emitting diodes (pc-LEDs) have gradually been widely used in industrial computers due to their energy-saving, long life, spectrum matching and environmental friendliness. As a light conversion material, phosphor plays an indispensable role in LED devices and directly determines the photoluminescence performance of LEDs. Therefore, it is of great significance to design and synthesize phosphors with suitable spectral emission and bright photoluminescence. Summary of the invention

[0004] 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 an LED phosphor, the luminous brightness and spectrum of the phosphor are matched, and the physical and chemical properties are stable and conducive to plant growth.

[0005] The invention also provides a method for preparing the LED fluorescent powder.

[0006] The present invention also proposes an application of the LED fluorescent powder in a plant growth promoting LED lamp.

[0007] According to the first aspect of the present invention, an LED phosphor is provided, the chemical formula of which is: NaLiZnS 2 :xMn 2+ ; where 0.05≤x≤0.5.

[0008] In some embodiments of the present invention, the above x is 0.1, 0.2, 0.3, 0.4 or 0.5.

[0009] In some embodiments of the present invention, the above x is 0.1, 0.2, 0.3 or 0.4.

[0010] In some embodiments of the present invention, the LED phosphor is a deep red sulfide phosphor.

[0011] In some embodiments of the present invention, the excitation peak of the LED phosphor is located at 250-550 nm.

[0012] In some embodiments of the present invention, the emission band of the LED phosphor is located at 600-800 nm.

[0013] According to a second aspect of the present invention, a method for preparing the above-mentioned LED phosphor is provided, the steps of which include:

[0014] S1: preparing a raw material mixture: weighing a sodium-containing compound, a lithium-containing compound, a zinc-containing compound and a manganese-containing compound in a certain proportion, grinding them in a mortar for 10-30 minutes;

[0015] S2: Calcination and post-processing: calcining the raw material mixture in a protective gas to obtain a sintered body; grinding the sintered body to obtain LED phosphor.

[0016] In some embodiments of the present invention, the ratio of the raw material mixture is: the molar ratio of the sodium-containing compound, the lithium-containing compound, the zinc-containing compound and the manganese-containing compound is 1:1:2:(0.05-0.5).

[0017] In some preferred embodiments of the present invention, the molar ratio of the manganese compound in the raw material mixture is 0.1, 0.2, 0.3, 0.4 or 0.5.

[0018] In some embodiments of the present invention, the sodium-containing compound includes at least one of sodium sulfide, sodium carbonate, sodium oxide, sodium hydroxide and sodium bicarbonate.

[0019] In some embodiments of the present invention, the lithium-containing compound includes at least one of lithium sulfide, lithium carbonate, lithium oxide, lithium hydroxide and lithium bicarbonate.

[0020] In some embodiments of the present invention, the zinc-containing compound includes at least one of zinc sulfide, zinc carbonate, zinc oxide, zinc hydroxide and basic zinc carbonate.

[0021] In some embodiments of the present invention, the manganese-containing compound includes at least one of manganese oxide, manganese carbonate, manganese sulfide, and manganese hydroxide.

[0022] In some preferred embodiments of the present invention, the sodium-containing compound, the lithium-containing compound and the zinc-containing compound refer to sodium sulfide, lithium sulfide and zinc sulfide, respectively; and the manganese-containing compound refers to manganese carbonate.

[0023] In some embodiments of the present invention, the protective gas is a nitrogen-hydrogen mixed gas, and the volume percentage of nitrogen is 90-95%.

[0024] In some preferred embodiments of the present invention, the protective gas is composed of 10% H 2 and 90% N 2 composition.

[0025] In some embodiments of the present invention, the specific calcination parameters are: heating to 700-800° C. and then sintering at this temperature for 6-10 hours.

[0026] In some preferred embodiments of the present invention, the specific calcination parameters are: heating to 730-770° C. and then sintering at this temperature for 7-9 hours.

[0027] In some more preferred embodiments of the present invention, the specific calcination parameters are: heating to 750° C. and then sintering at this temperature for 8 hours.

[0028] In some embodiments of the present invention, the specific operation of heating to 700-800° C. is: heating to 700-800° C. at a heating rate of 3-8° C. / min.

[0029] In some preferred embodiments of the present invention, the specific operation of heating to 700-800° C. is: heating to 700-800° C. at a heating rate of 4-6° C. / min.

[0030] In some more preferred embodiments of the present invention, the specific operation of heating to 700-800° C. is: heating to 700-800° C. at a heating rate of 5° C. / min.

[0031] According to a third aspect of the present invention, a use of the above LED phosphor or the LED phosphor prepared by the above preparation method in preparing a plant growth promoting LED lamp is proposed.

[0032] Compared with the prior art, the present invention has at least the following beneficial effects:

[0033] The phosphor provided by the present invention has a wide excitation band of 250 to 550 nm and a deep red emission band of 600 to 800 nm, and can be applied to plant growth LED lamps. The preparation process of the phosphor in the technical solution is simple, the synthesis temperature is low, and the physical and chemical properties are stable. The rich red light component is conducive to plant growth and has a high application prospect. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0035] Figure 1 XRD spectra of LED phosphors prepared in Examples 1 to 5 of the test examples of the present invention;

[0036] Figure 2 The excitation spectra of the LED phosphors prepared in Examples 1 to 5 in the test examples of the present invention;

[0037] Figure 3 The emission spectra of the LED phosphors prepared in Examples 1 to 5 in the test examples of the present invention;

[0038] Figure 4 This is a temperature-dependent spectrum diagram of the LED phosphor prepared in Example 2 of the test example of the present invention. DETAILED DESCRIPTION

[0039] The following will be combined with the embodiments to clearly and completely describe the concept of the present invention and the technical effects produced, so as to fully understand the purpose, characteristics and effects of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative work are all within the scope of protection of the present invention.

[0040] Example 1

[0041] This example prepared a Mn 2+ To activate the plant growth LED light with crimson sulfide phosphor, the specific steps are as follows:

[0042] (1) Prepare the raw material mixture: according to the general formula NaLiZnS 2 :xMn 2+ Accurately weigh sodium sulfide, lithium sulfide, zinc sulfide, and manganese carbonate in a chemical molar ratio of 1:1:2:0.1, put the raw materials into a mortar and grind them for 20 minutes (10-30 minutes is acceptable) to obtain a raw material mixture;

[0043] (2) Calcination and post-treatment: The raw material mixture obtained by grinding evenly was placed in a tube furnace and 10% H 2 Add 90% N2 Nitrogen and hydrogen mixed gas; then the temperature was raised to 750°C at a heating rate of 5°C / min, and calcined at 750°C for 8 hours, and then cooled to room temperature with the furnace to obtain a sintered body; the cooled sintered body was ground to prepare a sintered body with a molecular formula of NaLiZnS 2 :0.1Mn 2+ Mn 2+ Activated plant growth LED lights with deep red sulfide phosphor.

[0044] Example 2

[0045] This example prepared a Mn 2+ The activated plant growth LED lamp uses a deep red sulfide phosphor, which is different from Example 1 only in that in step (1), sodium sulfide, lithium sulfide, zinc sulfide, and manganese carbonate are weighed in a molar ratio of 1:1:2:0.2 to prepare a NaLiZnS 2 :0.2Mn 2+ Mn 2+ Activated plant growth LED lights with deep red sulfide phosphor.

[0046] Example 3

[0047] This example prepared a Mn 2+ The activated plant growth LED lamp uses a deep red sulfide phosphor, which is different from Example 1 only in that in step (1), sodium sulfide, lithium sulfide, zinc sulfide, and manganese carbonate are weighed in a molar ratio of 1:1:2:0.3 to prepare a phosphor with a molecular formula of NaLiZnS 2 :0.3Mn 2+ Mn 2+ Activated plant growth LED lights with deep red sulfide phosphor.

[0048] Example 4

[0049] This example prepared a Mn 2+ The activated plant growth LED lamp uses a deep red sulfide phosphor, which is different from Example 1 only in that in step (1), sodium sulfide, lithium sulfide, zinc sulfide, and manganese carbonate are weighed in a molar ratio of 1:1:2:0.4 to prepare a NaLiZnS 2 :0.4Mn 2+ Mn 2+ Activated plant growth LED lights with deep red sulfide phosphor.

[0050] Example 5

[0051] This example prepared a Mn 2+The activated plant growth LED lamp uses a deep red sulfide phosphor, which is different from Example 1 only in that in step (1), sodium sulfide, lithium sulfide, zinc sulfide, and manganese carbonate are weighed in a molar ratio of 1:1:2:0.5 to prepare a NaLiZnS 2 :0.5Mn 2+ Mn 2+ Activated plant growth LED lights with deep red sulfide phosphor.

[0052] Test Case

[0053] The Mn prepared in Example 1-5 2+ The activated plant growth LED lamp uses deep red sulfide phosphor to perform X-ray diffraction, fluorescence spectrum (including excitation light spectrum, emission spectrum) and variable temperature spectrum tests, and analyzes the phase composition and microstructure of the synthetic product to understand the relationship between the luminescence performance of the sample and the synthesis process parameters.

[0054] (1) Mn 2+ The XRD pattern of the activated plant growth LED lamp with deep red sulfide phosphor is compared with the standard pattern (ICSD: 417088) as shown in the figure Figure 1 As shown in the figure, it can be seen that the XRD spectrum of the phosphor prepared in Examples 1-5 shows that the relative intensity variation trend of the prepared phosphor is similar to that of NaLiZnS 2 This is consistent with the standard card, indicating that the phosphors synthesized in Examples 1-5 have higher purity.

[0055] (2) Mn 2+ The excitation spectrum of the activated plant growth LED lamp with deep red sulfide phosphor is shown in the figure below: Figure 2 As shown in the figure, it can be seen that the phosphors prepared in Examples 1-5 can be effectively excited in the ultraviolet and blue light bands, have an excitation band as wide as 250 to 550 nm, and are suitable as commercial fluorescent materials.

[0056] (3) Mn 2+ The emission spectrum of the activated plant growth LED lamp with deep red sulfide phosphor is shown in the figure below: Figure 3 As shown in the figure, it can be seen that the phosphors prepared in Examples 1-5 have a deep red emission band located at 600-800 nm, and the emission spectrum of the phosphors covers the band required for plant growth.

[0057] (4) Mn prepared in Example 2 2+ The temperature spectrum of the activated plant growth LED lamp with deep red sulfide phosphor is as follows Figure 4 As shown in the figure, it can be seen that the phosphor is a material with excellent thermal stability. The Mn2+ The results of the activated deep red sulfide phosphor for plant growth LED lamps are comparable to those of Example 2, both having good thermal stability.

[0058] The embodiments of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in the relevant technical field without departing from the purpose of the present invention. In addition, the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

Claims

1. An LED phosphor, characterized in that: Its chemical formula is: NaLiZnS2:xMn 2+ ; where 0.05≤x≤0.

5.

2. The LED phosphor according to claim 1, characterized in that: The x is 0.1, 0.2, 0.3, 0.4 or 0.

5.

3. A method for preparing the LED phosphor according to any one of claims 1 to 2, characterized in that: The following steps are involved: S1: Prepare a raw material mixture: weigh sodium sulfide, lithium sulfide, zinc sulfide and a manganese-containing compound in a certain proportion and grind them in a mortar for 10-30 minutes; S2: Calcination and post-processing: calcining the raw material mixture in a protective gas to obtain a sintered body; grinding the sintered body to obtain LED phosphor.

4. The preparation method according to claim 3, characterized in that: The added molar ratio of the sodium sulfide, lithium sulfide, zinc sulfide and the manganese-containing compound is 1:1:2:x; wherein 0.05≤x≤0.

5.

5. The preparation method according to claim 3, characterized in that: The manganese-containing compound includes at least one of its sulfide, oxide, hydroxide and carbonate.

6. The preparation method according to claim 3, characterized in that: The protective gas is a nitrogen-hydrogen mixed gas.

7. The preparation method according to claim 6, characterized in that: Nitrogen accounts for 90-95% of the total volume of the mixed gas.

8. The preparation method according to claim 3, characterized in that: The specific parameters of the calcination are: heating to 700-800° C. and then sintering at this temperature for 6-10 hours.

9. The preparation method according to claim 8, characterized in that: The specific operation of heating the temperature to 700-800° C. is: heating the temperature to 700-800° C. at a heating rate of 3-8° C. / min.

10. Use of the LED fluorescent powder according to any one of claims 1 to 2 or the LED fluorescent powder prepared by the preparation method according to any one of claims 3 to 9 in preparing a plant growth promoting LED lamp.

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