Yellow fluorescent material capable of being excited by near ultraviolet light and visible light and preparation method thereof

Abstract

The invention provides a yellow fluorescent material capable of being excited by near ultraviolet light and visible light and a preparation method of the yellow fluorescent material, the method comprises the following steps: providing raw materials which comprise the following components in parts by weight: 0.3524 to 0.3564 part of K2CO3, 0.7012 to 0.7386 part of SrCO3, 0.5250 to 0.5368 part of Y2O3, 2.1586 to 2.1596 part of MoO3 and 0.0466 to 0.0839 part of Dy2O3, and uniformly mixing the components; heating the raw materials to a preset temperature, and keeping the temperature; and cooling to obtain the yellow fluorescent material capable of being excited by near ultraviolet light and visible light. The method is simple to operate, a fluxing agent does not need to be additionally added, the excitation wavelength required by the prepared fluorescent powder is located in the near ultraviolet-visible light wave band, the half-peak width of emitted light is narrow, and the color purity is high.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fluorescent materials, in particular to a yellow fluorescent material excited by near-ultraviolet light and visible light and a preparation method thereof. BACKGROUND

[0002] Lighting technology is an important symbol of the development of human civilization, and luminescent materials are the essential material basis for lighting technology. Fluorescent materials are luminescent materials that absorb light energy and emit specific wavelengths of light, and have specific luminescent colors with different emission wavelengths. They are the most widely used materials in the field of luminescent lighting. The luminescent principle of fluorescent powder is electron transition luminescence. After the electron is excited from the ground state to the excited state, it jumps back to the ground state from the excited state, and the absorbed energy is released in the form of light radiation.

[0003] The earliest used fluorescent powder materials are CaWO4 blue fluorescent powder, CdB2O5:Mn 2+ red fluorescent powder and Zn2SiO4:Mn 2 + green fluorescent powder, etc. The main component of calcium halophosphate fluorescent powder (referred to as "halide powder") is 3Ca3(PO4)2·Ca(F,Cl)2:Sb 3+ , Mn 2+ , which is a widely used single component, luminescent color adjustable, high luminescent efficiency fluorescent powder. With the deepening of research, the shortcomings of traditional fluorescent powder gradually appear, such as low color purity, short excitation wavelength, etc. Therefore, it is necessary to study new fluorescent powder materials.

[0004] The three primary color fluorescent powders in the currently commercial fluorescent powders are relatively mature, but yellow fluorescent powder needs to be studied because of its wide range of luminescence wavelength and lack of certain red light components.

[0005] Chinese patent CN1760326A discloses a composite oxide fluorescent powder for white light LED and an electric light source made of the same, and records Li 1.96 MoO4:Dy 0.02The preparation of the fluorescent powder, taking MoO3 3.2745g, Li2CO31.6473g, Dy2O30.0783g, KF 0.005g, wherein, KF as a reaction flux, the raw material is mixed and ground uniformly, then is loaded into an alumina crucible and fired in air, and is kept at 800 DEG C for 3 hours, the obtained product is crushed, washed with water to remove impurities, and dried to obtain an orange-yellow light fluorescent powder. The fluorescent powder can be effectively excited by light with a wavelength of about 300-490nm to emit yellow light with a main peak wavelength of about 572nm. However, the fluorescent powder in the prior art uses lithium-containing compounds, and the synthesis needs fluorine-containing flux, which is high in cost and toxic, and the water washing and other steps in the preparation process cause pollution and waste of raw materials. In addition, the fluorescent powder has a large half peak width, and the prior art fails to successfully prepare a narrow-band yellow light fluorescent powder. SUMMARY

[0006] In view of the defects in the prior art, the purpose of the present application is to provide a yellow light fluorescent material that can be excited by near-ultraviolet light and visible light and a preparation method thereof.

[0007] The present application is realized by the following technical solutions:

[0008] According to one aspect of the present application, a preparation method of a yellow light fluorescent material that can be excited by near-ultraviolet light and visible light is provided, and the method comprises:

[0009] Providing raw materials, the raw materials comprising the following components by weight: 0.3524-0.3564 parts of K2CO3, 0.7012-0.7386 parts of SrCO3, 0.5250-0.5368 parts of Y2O3, 2.1586-2.1596 parts of MoO3, and 0.0466-0.0839 parts of Dy2O3, and mixing the components uniformly;

[0010] Heating the raw materials to a preset temperature and keeping the temperature;

[0011] After cooling, a yellow light fluorescent material that can be excited by near-ultraviolet light and visible light is obtained.

[0012] Optionally, the raw materials are heated to a preset temperature, wherein: heating at a speed of 2-4 DEG C / min to 800-1000 DEG C.

[0013] Optionally, the keeping time is 5-10h.

[0014] Optionally, the cooling comprises: cooling to ambient temperature.

[0015] Optionally, the method further comprises: after cooling, grinding to form a powder.

[0016] Optionally, the excitation wavelength of the near-ultraviolet light is 352 nm, 366 nm and 387 nm, and the excitation wavelength of the visible light is 454 nm.

[0017] According to another aspect of the present application, there is provided a yellow light fluorescent material which can be excited by near-ultraviolet light and visible light, prepared by the method for preparing a yellow light fluorescent material which can be excited by near-ultraviolet light and visible light.

[0018] Further, the yellow light fluorescent material is KSrY n (MoO4)3 as a host compound, wherein n = 0.91-0.95.

[0019] Further, the doping element in the yellow light fluorescent material is Dy 3+ , and the content of the doping element is 5-9 mol%.

[0020] Further, the emission band of the yellow light fluorescent material is 557-600 nm.

[0021] Compared with the prior art, the present application has at least one of the following beneficial effects:

[0022] 1. The method for preparing a yellow light fluorescent material provided by the present application has fewer types of raw materials, simple operation, simple equipment required, and the required excitation wavelength of the prepared fluorescent powder is in the near-ultraviolet-visible light band, and the emission light half-width of Dy 3+ is very narrow, and the color purity is high.

[0023] 2. In the raw material used in the present application, the melting point of MoO3 is 795℃, which can reduce the sintering temperature of the fluorescent material, promote the densification of the material, and thus improve the luminous efficiency and stability of the fluorescent powder. In addition, MoO3 can also improve the electronic structure and optical properties of the fluorescent powder by forming a solid solution or providing oxygen vacancies, and molybdenum oxide can also be used as a matrix material of the fluorescent powder, which can affect the electronic structure and luminescent properties of the fluorescent powder through its semiconductor properties and good electrochemical activity. Potassium carbonate has a low decomposition temperature and can be decomposed at 900℃, so it can participate in the reaction and also act as a fluxing agent, so the reaction can occur at a lower temperature without the need to add additional fluxing agents. Since no fluorine-containing fluxing agent is used, the preparation method of the present application has low toxicity and low cost, and is not easy to cause pollution. BRIEF DESCRIPTION OF DRAWINGS

[0024] Other features, objects and advantages of the present application will become more apparent from the following detailed description of non-limiting embodiments, made with reference to the accompanying drawings:

[0025] Figure 1 The fluorescent powder KSrY 0.93(MoO4)3:0.07Dy 3+ XRD pattern of the fluorescent powder KSrY

[0026] Figure 2 XRD pattern of the fluorescent powder KSrY 0.93 (MoO4)3:0.07Dy 3+ fluorescent spectrum of the fluorescent powder KSrY

[0027] Figure 3 fluorescent spectrum of the fluorescent powder KSrY 0.93 (MoO4)3:0.07Dy 3+ fluorescent spectrum of the fluorescent powder KSrY

[0028] Figure 4 fluorescent spectrum of the fluorescent powder KSrY 0.93 (MoO4)3:0.07Dy 3+ fluorescent spectrum of the fluorescent powder KSrY

[0029] Figure 5 fluorescent spectrum of the fluorescent powder KSrY 0.93 (MoO4)3:0.07Dy 3+ fluorescent spectrum of the fluorescent powder KSrY DETAILED DESCRIPTION

[0030] The present application will be described in detail below with specific embodiments. The following examples will help those skilled in the art to further understand the present application, but do not limit the present application in any form. It should be noted that for those skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made. These all belong to the protection scope of the present application.

[0031] Example 1

[0032] The present application provides a preparation method of a yellow fluorescent material which can be excited by near-ultraviolet light and visible light. The preparation method comprises the following steps:

[0033] Step S1: Put 0.3524 grams of K2CO3, 0.7012 grams of SrCO3, 0.5250 grams of Y2O3, 2.1591 grams of MoO3 and 0.0653 grams of Dy2O3 into an agate mortar and grind and mix.

[0034] Step S2: After sufficient mixing, the ground powder is placed in an alumina crucible and heated to 900℃ at a rate of 3℃ / min in a box furnace, and kept for 8h.

[0035] Step S3: After cooling to ambient temperature, the sintered solid product is removed and re-ground into powder in an agate mortar to obtain yellow fluorescent powder KSrY. 0.93 (MoO4)3:0.07Dy 3+ Its XRD pattern is as follows: Figure 1 The figure shows that KSrY was actually prepared. 0.93 (MoO4)3:0.07Dy 3+ Its fluorescence spectrum is as follows: Figures 2-5 As shown, the excitation wavelengths are 352nm, 366nm, 387nm and 454nm, respectively.

[0036] In step S1, after weighing each raw material, they are ground and mixed to ensure uniform mixing, which is beneficial for the reaction between the raw materials.

[0037] In step S2, a slower heating rate of 3°C / min allows Dy to... 3+ Sufficient ion diffusion prevents lattice distortion or defects caused by excessively high local concentrations, ensuring doping uniformity; it also helps reduce lattice stress caused by size mismatch, maintaining KSrY n The (MoO4)3 matrix structure is stable. Furthermore, the 8-hour holding time promotes complete reaction of the raw materials, avoids the formation of impurity phases, and ensures a single-phase crystal structure.

[0038] In step S3, the temperature is slowly cooled to ambient temperature after the initial heat treatment. The reason for slow cooling is that rapid cooling at high temperatures can easily introduce oxygen vacancies, while slow cooling after a long heat treatment can promote vacancy healing and reduce non-radiative transition centers.

[0039] In this embodiment of the invention, the excitation wavelengths for near-ultraviolet light are 352 nm, 366 nm, and 387 nm, and the excitation wavelength for visible light is 454 nm. Here, the specific but not continuous excitation wavelengths are mainly due to the rare earth ion Dy 3+ The energy level transition characteristics of Dy 3+ The 4f electrons are received by the outer 5s electrons 2 5p 6 Orbital shielding, whose excitation originates from energy level transitions within the 4f configuration, corresponds to a precise energy level difference at a specific wavelength (theoretically, dozens of absorption lines can be generated, but in practice, only the above-mentioned ones are usually observed). The energy level transitions must satisfy strict parity selection rules.

[0040] In this embodiment of the invention, the yellow fluorescent material comprises a host compound and dopant elements. KSrY n (MoO4)3 is the main compound, where n = 0.93. The dopant element in the yellow fluorescent material is Dy. 3+ The content of doped elements is 0.07 mol%.

[0041] In the above embodiments, KSrY 0.93 (MoO4)3 is a trimolybdate with a disordered structure, containing the alkaline earth metal ion Sr 2+ The ionic radius is relatively large, and the rare earth ion Y has a large ionic radius. 3+ Smaller radii (promote lattice stability and reduce distortion). Trimolybdate crystal structures exhibit different formation tendencies in monoclinic or tetragonal crystal systems: smaller radii of alkaline earth metal ions (such as Ca)... 2+ Mg 2+ Alkaline earth metal ions with larger radii (such as Sr in this example) tend to form tetragonal crystal structures; 2+ , and Ba 2 + KSrY tends to form a monoclinic crystal structure. 0.93 (MoO4)3 has lower symmetry, which is more conducive to reducing Dy 3+ Blue light emission, Dy 3+ It has a high proportion of yellow light emission and a large luminous intensity.

[0042] In this embodiment of the invention, the emission band of the yellow fluorescent material is 557-600 nm, with a width of 43 nm. Typically, a full width at half maximum (FWHM) ≤ 50 nm is considered a typical narrow band. Figures 2-5 It can be seen that the KSrY prepared in this embodiment 0.93 (MoO4)3:0.07Dy 3+ The yellow phosphor can be effectively excited by near-ultraviolet light at 352nm, 366nm, and 387nm, and by blue light at 454nm. The main emission peak is located at 573nm, with a very narrow half-width of only 10nm. Furthermore, the emission peak intensities of blue, red, and near-infrared light are very low, and the emitted color is yellow with high color purity (the main emission peak is single and sharp, and impurity peaks are significantly suppressed).

[0043] In this embodiment of the invention, the fluorescence spectrometer used is FS-5, Edinburgh Company, UK; the test range is 450-780 nm.

[0044] Example 2

[0045] This embodiment provides a method for preparing a yellow fluorescent material that can be excited by near-ultraviolet and visible light, including the following steps:

[0046] Step S1: Grind and mix 0.3554 g K2CO3, 0.7376 g SrCO3, 0.5358 g Y2O3, 2.1586 g MoO3 and 0.0466 g Dy2O3 in an agate mortar.

[0047] Step S2: After sufficient mixing, the ground powder is placed in an alumina crucible and heated to 800℃ at a rate of 2℃ / min in a box furnace, and kept for 5h.

[0048] Step S3: After cooling to ambient temperature, the sintered solid product is taken out and re-ground into powder in an agate mortar to obtain yellow phosphor KSrY 0.91 (MoO4)3:0.09Dy 3+ .

[0049] Example 3

[0050] The present embodiment provides a preparation method of yellow phosphor which can be excited by near-ultraviolet light and visible light, comprising the following steps:

[0051] Step S1: 0.3564g of K2CO3, 0.7386g of SrCO3, 0.5368g of Y2O3, 2.1596g of MoO3 and 0.0839g of Dy2O3 are placed in an agate mortar and ground and mixed.

[0052] Step S2: After sufficient mixing, the ground powder is placed in an alumina crucible and heated to 1000℃ at a rate of 4℃ / min in a box furnace, and kept for 10h.

[0053] Step S3: After cooling to ambient temperature, the sintered solid product is taken out and re-ground into powder in an agate mortar to obtain yellow phosphor KSrY 0.95 (MoO4)3:0.05Dy 3+ .

[0054] It is tested that the fluorescence spectrum of the phosphor prepared in Example 2 and Example 3 is close to that of Example 1, proving that the yellow phosphor prepared in the above two examples can be effectively excited by near-ultraviolet light and visible light, and has a relatively narrow half peak width and a relatively high color purity.

[0055] The specific embodiments of the present application are described above. It should be understood that the present application is not limited to the above specific embodiments, and various modifications or changes can be made by those skilled in the art within the scope of the claims, which does not affect the essential content of the present application. The above preferred features can be used in combination as long as they are not in conflict with each other.

Claims

1. A method for preparing a yellow fluorescent material that can be excited by near-ultraviolet and visible light, characterized in that, The method comprises the following steps: providing raw materials, the raw materials comprising the following components in parts by weight: 0.3524-0.3564 parts of K2CO3, 0.7012-0.7386 parts of SrCO3, 0.5250-0.5368 parts of Y2O3, 2.1586-2.1596 parts of MoO3 and 0.0466-0.0839 parts of Dy2O3, and mixing the components uniformly; heating the raw materials to a preset temperature and keeping the temperature; after cooling, obtaining a yellow light fluorescent material that can be excited by near-ultraviolet light and visible light.

2. The method of producing a yellow fluorescent material which can be excited by near-ultraviolet light and visible light according to claim 1, characterized by, heating the raw materials to a preset temperature, wherein: heating at a speed of 2-4 ℃ / min to 800-1000 ℃.

3. The method of producing a yellow fluorescent material which can be excited by near-ultraviolet light and visible light according to claim 1, characterized by, the keeping time is 5-10 h.

4. The method of producing a yellow fluorescent material which can be excited by near-ultraviolet light and visible light according to claim 1, characterized by, the cooling comprises: cooling to ambient temperature.

5. The method of producing a yellow fluorescent material which can be excited by near-ultraviolet light and visible light according to claim 1, characterized by, The method further comprises: after cooling, performing grinding to form a powder.

6. The method of producing a yellow fluorescent material which can be excited by near-ultraviolet light and visible light according to claim 1, characterized by, the excitation wavelength of the near-ultraviolet light is 352 nm, 366 nm and 387 nm, and the excitation wavelength of the visible light is 454 nm.

7. A yellow fluorescent material that can be excited by near-ultraviolet and visible light, characterized in that, obtained by the method for preparing a yellow light fluorescent material that can be excited by near-ultraviolet light and visible light according to any one of claims 1-6.

8. The yellow fluorescent material which can be excited by near-ultraviolet light and visible light according to claim 7, wherein The yellow fluorescent material is KSrY n (Mo04)3 as a host compound, wherein n = 0.91-0.

95.

9. The yellow fluorescent material which can be excited by near-ultraviolet light and visible light according to claim 7, wherein The doping element in the yellow light fluorescent material is Dy 3+ , and the content of the doping element is 5-9 mol%.

10. The yellow fluorescent material which can be excited by near-ultraviolet light and visible light according to claim 7, wherein the emission band of the yellow light fluorescent material is 557-600 nm.

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