Yellow composite fluorescent pigment with improved luminous intensity and preparation method thereof

Abstract

The application belongs to the technical field of fluorescent pigments, and particularly discloses a yellow composite fluorescent pigment for improving luminous intensity and a preparation method thereof, which comprises the following steps: preparing yellow fluorescent powder: taking Y2O3, Al(NO3)3.9H2O and Ce(NO3)3.6H2O, BaF2 and NH4F, and sintering; preparing blue fluorescent powder: taking BaMgAl 10 O 17 ∶Eu 2+ taking raw materials, adding BaF2 and NH4F, and sintering; preparing film raw materials; compounding and curing: mixing the yellow fluorescent powder and the blue fluorescent powder at a mass ratio of 1:0.5-2, adding the mixed fluorescent powder into the film raw materials, and performing high-temperature solid-phase treatment. The yellow composite fluorescent pigment for improving luminous intensity and the preparation method thereof can overcome the problems of low color temperature and low color rendering index of the traditional yellow fluorescent powder, improve the luminous intensity of the yellow fluorescent powder, and expand the spectral response range of the yellow fluorescent powder.

Description

Technical Field

[0001] This invention relates to the field of fluorescent pigment technology, and in particular to a yellow composite fluorescent pigment for enhancing luminescence intensity and its preparation method. Background Technology

[0002] Fluorescent pigments are substances that, after absorbing a certain wavelength of light, emit light of a wavelength longer than the absorbed wavelength. When ultraviolet light or other light shines on a fluorescent pigment, it absorbs energy corresponding to its characteristic frequency, transitioning from the ground state to a higher-energy excited state. The atoms in the unstable excited state briefly relax to the lowest vibrational energy level of the excited state, i.e., the equilibrium excited state, before falling back to a higher vibrational energy level of the ground state. During this fallback, the energy decays in the form of fluorescence, and the fluorescence disappears when irradiation stops.

[0003] Fluorescent pigments are divided into inorganic fluorescent pigments (such as those used in fluorescent lamps and anti-counterfeiting inks) and organic fluorescent pigments (also known as daylight fluorescent pigments): only substances with specific chemical structures possess fluorescent properties. However, these fluorescent colorants often have inherent deficiencies in lightfastness and solvent resistance. The solution is to fuse them into the framework of polymer materials through chemical or physical methods, and then further process them into pigments. The polymer materials used for this purpose act as both solvents and protectors for the fluorescent colorants, thus giving them better lightfastness and solvent resistance.

[0004] Blue light excites Ce 3+ Yttrium aluminum garnet phosphor is the earliest and most maturely studied yellow phosphor, with the chemical formula Y3Al5O. 12 Ce 3+ YAG, also abbreviated as Ce, is the most common and widely used commercial phosphor. It serves as an excellent fluorescent pigment due to its advantages: aluminate phosphors are highly stable compounds with excellent luminescent properties, good reliability, high brightness, and a broad emission peak. Furthermore, the production process of YAG phosphors is relatively fixed, easy to synthesize, and the raw materials are relatively inexpensive. However, YAG phosphors have disadvantages, including a low color rendering index, a narrow excitation band, and the ability to absorb only a portion of visible light, which limits their application range.

[0005] In the prior art, yellow phosphors (such as YAG:Ce) 3+ Blue light-excited phosphors (such as YAG:Ce) have a low color rendering index and a narrow absorption spectrum, limiting their application in high-performance lighting and displays. For example, traditional blue light-excited phosphors (such as YAG:Ce) have a low color rendering index and a narrow absorption spectrum, which limits their application in high-performance lighting and displays. 3+Yellow phosphors can only absorb blue light or a small amount of ultraviolet light, thus limiting their light output intensity under broad-spectrum excitation conditions. Furthermore, existing yellow phosphors have limited color temperature adjustment capabilities, often exhibiting a cool tone, which cannot meet the needs of certain applications. Summary of the Invention

[0006] The purpose of this invention is to provide a yellow composite fluorescent pigment with enhanced luminescence intensity and its preparation method, which overcomes the problems of cold color temperature and low color rendering index of traditional yellow phosphors, enhances the luminescence intensity of yellow phosphors, and expands their spectral response range.

[0007] To achieve the above objectives, the present invention provides a method for preparing a yellow composite fluorescent pigment with enhanced luminescence intensity, comprising the following steps: S1. Preparation of yellow phosphor: According to the stoichiometric ratio of Ce-doped garnet structure phosphor, Y2O3, Al(NO3)3·9H2O and Ce(NO3)3·6H2O are taken as raw materials, mixed and ground to obtain the first raw material powder. BaF2 and NH4F are added to the first raw material powder, ground, sintered at 800~1500℃ in a reducing atmosphere for 1~12h, cooled in the furnace and ground to obtain yellow phosphor; S2. Preparation of blue phosphor: According to the chemical formula BaMgAl 10 O 17 Eu 2+ The stoichiometric ratio of each element in the mixture was determined by taking Ba(NO3)2, Mg(NO3)2·6H2O, Al(NO3)3·9H2O and Eu2O3 as raw materials, mixing and grinding them to obtain a second raw material powder. BaF2 and NH4F were added to the second raw material powder, and the mixture was ground. The powder was then sintered at 800~1500℃ in a reducing atmosphere for 1~12h, cooled in the furnace, and ground again to obtain a blue fluorescent powder. S3. Preparation of film raw materials: Take the main agent and curing agent at a mass ratio of 1~20:1, mix them, and obtain the film raw materials; S4. Composite and curing: Take the yellow phosphor obtained in S1 and the blue phosphor obtained in S2 at a mass ratio of 1:0.5~2, mix them to obtain a mixed phosphor, add the mixed phosphor to the film raw material obtained in S3, and treat it by high temperature solid-state method or hot injection method to obtain yellow composite fluorescent pigment.

[0008] The refractive index matching design of the yellow composite fluorescent pigment involves mixing a yellow phosphor excited by blue light, a blue phosphor excited by ultraviolet light, and specific thin-film raw materials. The blue phosphor can absorb ultraviolet light that the yellow phosphor cannot absorb. Furthermore, since the emission peak of the blue phosphor coincides with the excitation peak of the yellow phosphor, this property is used to enhance the luminescence intensity and applicability of the yellow phosphor. However, simply mixing the two phosphors does not effectively achieve light transmission. When light travels from a denser medium with a higher refractive index to a less dense medium with a lower refractive index, the angle of refraction is greater than the angle of incidence, allowing for better light transmission in the denser medium. Firstly, by utilizing the refractive index matching between the mixed phosphor and the thin-film raw material matrix, effective light transmission and coupling occur at the interface, reducing light scattering losses and improving fluorescence intensity and luminescence efficiency. Secondly, by utilizing the property that the refractive index of the phosphor in the thin-film material is greater than its refractive index in air, the fluorescence generated by the blue phosphor after being excited by ultraviolet light is reflected at the interface of the thin-film material and transmitted to the yellow phosphor, further enhancing the fluorescence intensity.

[0009] Preferably, in S1, the Ce-doped garnet structure phosphor is specifically Y3Al5O 12 ∶Ce 3+ or (Y) 2.5 Ce 0.5 Al5O 12 .

[0010] Preferably, in S1, the amounts of BaF2 and NH4F added are 0.1 to 5% of the mass of the first raw material powder, respectively.

[0011] Preferably, in S2, the amounts of BaF2 and NH4F added are 0.1 to 5% of the mass of the second raw material powder, respectively.

[0012] Preferably, in S1 and S2, the reducing atmosphere comprises 95% N2 and 5% H2, by volume percentage.

[0013] Preferably, in S1 and S2, the refractive index range of the yellow phosphor and the blue phosphor is 1.55~1.60.

[0014] Preferably, in S3, the main agent is one or more of silicone rubber polydimethylsiloxane (PDMS), epoxy resin, polycarbonate or acrylamide; The curing agent is one or more of ethylbenzene, vinyltriamine, and ethylenediamine; The refractive index of the thin film material is in the range of 1.5 to 1.6. Because when the refractive index of the phosphor is similar to that of the resin, the refractive index of light at the interface between the two (such as total internal reflection) is easily and greatly reduced, so that the light is effectively transferred from blue to yellow. This allows the yellow phosphor to not only emit fluorescence when excited by visible light, but also to be re-excited by the fluorescence emitted by the blue phosphor when excited by ultraviolet light to produce yellow fluorescence.

[0015] Preferably, the film material further includes ceramic or glass, and the mixed phosphor is dispersed in the ceramic or glass to obtain a yellow composite fluorescent pigment. Because the refractive index of ceramic or glass (typically exceeding 1.4) is higher than that of air, it increases the light transmission from the blue phosphor to the yellow phosphor, thereby increasing the brightness of the yellow color from the outdoor panel.

[0016] Preferably, in S4, the high-temperature solid-state method specifically refers to: After being thoroughly mixed in a vacuum centrifuge, the mixture is pre-cured at 20~180℃ for 0.5~6h, and then cured at 100~300℃ for 0.5~10h to obtain a yellow composite fluorescent pigment. The amount of the mixed phosphor added is 5-50% of the mass of the film raw material.

[0017] Preferably, in S4, the yellow phosphor obtained in S1 and the blue phosphor obtained in S2 are taken at a mass ratio of 1:0.5 and mixed to obtain a mixed phosphor.

[0018] The present invention also provides a yellow composite fluorescent pigment that enhances luminescence intensity.

[0019] Preferably, under blue light and ultraviolet light excitation conditions, the color coordinate adjustment range of the yellow composite fluorescent pigment is (0.21, 0.18) to (0.19, 0.39), and its luminescence intensity is increased by 15-30%.

[0020] Therefore, the present invention employs the above-mentioned method for preparing a yellow composite fluorescent pigment that enhances luminescence intensity, and the beneficial effects are as follows: Compared to traditional yellow phosphors, the yellow composite fluorescent pigment of this invention, through a composite design of blue light excitation and ultraviolet light excitation, significantly expands the excitable spectral range of yellow phosphors, achieving efficient luminescence in multiple wavelength bands and effectively improving its luminescence intensity. Experimental results show that under blue light excitation and ultraviolet light excitation conditions, the luminescence intensity of the yellow composite fluorescent pigment is increased by 15-30%, thus meeting the requirements of high-end lighting and display fields for high color rendering index and high brightness, and is suitable for high-performance lighting, displays, and coatings.

[0021] Color temperature adjustment: The yellow composite fluorescent pigment of the present invention has a wide range of color temperature adjustment. Experimental results show that its emission color coordinates can be continuously adjusted in the range of (0.21, 0.18) to (0.19, 0.39) in the CIE 1931 chromaticity diagram, indicating that its output light color coverage is wide and it is suitable for applications under various light source conditions.

[0022] Color stability: Due to the use of a composite structure of multiple phosphors, the yellow composite fluorescent pigment of this invention can maintain good color stability during long-term use. Experimental results show that under pressure cycling conditions of 0~15GPa, its luminescence characteristics have good recoverability after decompression, and the recovery ability of key optical properties can reach more than 80%, demonstrating good color stability and cycling reliability.

[0023] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0024] Figure 1 This is a comparison diagram of the emission spectrum of the phosphor in an embodiment of the present invention, which describes a yellow composite fluorescent pigment for enhancing luminescence intensity and its preparation method. Figure 2 This is a comparative image of a spectral color illuminance meter of an embodiment of the present invention, which describes a yellow composite fluorescent pigment for enhancing luminescence intensity and its preparation method. Figure 3 This is an emission spectrum of a fluorescent pigment according to an embodiment of the present invention, which is a yellow composite fluorescent pigment for enhancing luminescence intensity and a method for preparing the same. Figure 4 These are visible light excitation effect diagrams of an embodiment of the present invention, which describes a yellow composite fluorescent pigment for enhancing luminescence intensity and its preparation method. (a) is Comparative Example 1, (b) is Example 1, (c) is Example 2, and (d) is Example 3. Figure 5 These are ultraviolet light excitation effect diagrams of an embodiment of the present invention, which describes a yellow composite fluorescent pigment for enhancing luminescence intensity and its preparation method. (a) is Comparative Example 1, (b) is Example 1, (c) is Example 2, and (d) is Example 3. Figure 6 The results of CIE 1931 chromaticity diagrams for Examples 1 and 3 of the present invention, which describe a yellow composite fluorescent pigment for enhancing luminescence intensity and its preparation method. Figure 7 This is a graph showing the relationship between luminescence intensity and wavelength under different pressure conditions in Example 1 of the present invention, which describes a yellow composite fluorescent pigment for enhancing luminescence intensity and its preparation method. Detailed Implementation

[0025] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0026] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0027] Example 1 A yellow composite fluorescent pigment for enhancing luminescence intensity, specifically yellow phosphor Y3Al5O 12 Ce 3+ Blue fluorescent powder BaMgAl 10 O 17 Eu 2＋ The preparation method of the composite fluorescent pigment is as follows: According to the chemical formula Y3Al5O 12 ∶Ce 3+ The stoichiometric ratios of each element were determined by taking yttrium oxide (Y₂O₃), aluminum nitrate (Al(NO₃)₃·9H₂O), and cerium nitrate (Ce(NO₃)₃·6H₂O), mixing and grinding them to obtain the first raw material powder. BaF₂ (5% by mass of the first raw material powder) and NH₄F (0.5% by mass of the first raw material powder) were added and ground evenly using an agate mortar. The powder was then placed in an alumina crucible and sintered for 5 hours at 1500℃ in an alumina tube furnace under a reducing atmosphere of 95% N₂ + 5% H₂. After cooling to room temperature in the furnace, the calcined product was ground to obtain the yellow fluorescent powder Y₃Al₅O₃. 12 Ce 3+ ; According to the chemical formula BaMgAl 10 O 17 Eu 2＋ The stoichiometric ratios of each element were determined by taking Ba(NO3)2, Mg(NO3)2·6H2O, Al(NO3)3·9H2O, and Eu2O3 (99.99%), mixing and grinding them to obtain a second raw material powder. BaF2 (5% by mass of the second raw material powder) and NH4F (0.5% by mass of the second raw material powder) were added, and the mixture was placed in an alumina crucible and sintered in air at 1500℃ for 5 hours. After cooling to room temperature in the furnace, the product was ground to obtain the blue fluorescent powder BaMgAl. 10 O 17 Eu 2 ＋ ; Weigh 1.89g of silicone rubber polydimethylsiloxane and 0.21g of ethylbenzene curing agent, mix them, and form a film raw material; Take 0.2g of yellow phosphor and 0.1g of blue phosphor, mix them to obtain mixed phosphor, add it to the film raw material, put it in a vacuum centrifuge to mix thoroughly, place it in an oven at 60℃ for 0.5h for pre-curing, and then at 100℃ for 2h to obtain yellow composite fluorescent pigment.

[0028] Example 2 A yellow composite fluorescent pigment for enhancing luminescence intensity, specifically yellow phosphor (Y). 2.5 Ce 0.5 Al5O 12 Blue fluorescent powder BaMgAl 10 O 17 Eu 2＋ The preparation method of the composite fluorescent pigment is as follows: According to the chemical formula (Y) 2.5 Ce 0.5 Al5O 12 The stoichiometric ratios of each element were determined by taking Y₂O₃, Al(NO₃)₃·9H₂O, and Ce(NO₃)₃·6H₂O, mixing and grinding them to obtain the first raw material powder. BaF₂ (5% by mass of the first raw material powder) and NH₄F (0.5% by mass of the first raw material powder) were added and ground evenly using an agate mortar. The powder was then placed in an alumina crucible and sintered for 5 hours in an alumina tube furnace at 800℃ under a reducing atmosphere of 95% N₂ + 5% H₂. After cooling to room temperature with the furnace, the sintered material was ground to obtain the yellow fluorescent powder (Y₂O₃). 2.5 Ce 0.5 Al5O 12 ; According to the chemical formula BaMgAl 10 O 17 Eu 2+ The stoichiometric ratios of each element were determined by taking Ba(NO3)2, Mg(NO3)2·6H2O, Al(NO3)3·9H2O, and Eu2O3 (99.99%), mixing and grinding them to obtain a second raw material powder. BaF2 (5% by mass of the second raw material powder) and NH4F (0.5% by mass of the second raw material powder) were added, and the mixture was placed in an alumina crucible and sintered in air at 1500℃ for 5 hours. After cooling to room temperature in the furnace, the product was ground to obtain the blue fluorescent powder BaMgAl. 10 O 17 Eu 2 + .

[0029] Weigh 1.89g of PDMS silicone rubber polydimethylsiloxane main agent and 0.21g of ethylbenzene curing agent at a mass ratio of 9:1 to obtain film raw material. At the same time, weigh 0.2g of yellow phosphor and 0.2g of blue phosphor to obtain mixed phosphor. Add the mixed phosphor to the film raw material, put it in a vacuum centrifuge to mix thoroughly, put it in an oven at 60℃ for pre-curing for 0.5h, and then cure it at 100℃ for 2h to obtain yellow composite fluorescent pigment.

[0030] Example 3 A yellow composite fluorescent pigment for enhancing luminescence intensity, specifically yellow phosphor Y3Al5O 12 Ce 3+ Blue fluorescent powder BaMgAl 10 O 17 Eu 2+ The preparation method of the composite fluorescent pigment is as follows: According to the chemical formula Y3Al5O 12 Ce 3+ The stoichiometric ratios of each element were determined by taking Y₂O₃, Al(NO₃)₃·9H₂O, and Ce(NO₃)₃·6H₂O, mixing and grinding them to obtain the first raw material powder. BaF₂ (5% by mass of the first raw material powder) and NH₄F (0.5% by mass of the first raw material powder) were added and ground evenly using an agate mortar. The powder was then placed in an alumina crucible and sintered for 5 hours at 1500℃ in an alumina tube furnace under a reducing atmosphere of 95% N₂ + 5% H₂. After cooling to room temperature in the furnace, the sintered material was ground to obtain the yellow fluorescent powder Y₃Al₅O₃. 12 Ce 3+ ; According to the chemical formula BaMgAl 10 O 17 Eu 2+ The stoichiometric ratios of each element were determined by taking Ba(NO3)2, Mg(NO3)2·6H2O, Al(NO3)3·9H2O, and Eu2O3 (99.99%), mixing and grinding them to obtain a second raw material powder. BaF2 (5% by mass of the second raw material powder) and NH4F (0.5% by mass of the second raw material powder) were added, and the mixture was placed in an alumina crucible and sintered in air at 1500℃ for 5 hours. After cooling to room temperature in the furnace, the product was ground to obtain the blue fluorescent powder BaMgAl. 10 O 17 Eu 2 + ; Weigh 1.89g of silicone rubber polydimethylsiloxane and 0.21g of ethylbenzene curing agent, mix them, and form a film raw material; Take 0.2g of yellow phosphor and 0.4g of blue phosphor, mix them to obtain mixed phosphor, add it to the film raw material, put it in a vacuum centrifuge to mix thoroughly, place it in an oven at 60℃ for 0.5h for pre-curing, and then at 100℃ for 2h to obtain yellow composite fluorescent pigment.

[0031] Comparative Example 1 A yellow fluorescent pigment, specifically Y3Al5O 12 Ce 3+ Its preparation method is as follows: According to the chemical formula Y3Al5O 12 ∶Ce 3+ The stoichiometric ratios of each element were determined by taking yttrium oxide (Y₂O₃), aluminum nitrate (Al(NO₃)₃·9H₂O), and cerium nitrate (Ce(NO₃)₃·6H₂O), mixing and grinding them to obtain the first raw material powder. BaF₂ (5% by mass of the first raw material powder) and NH₄F (0.5% by mass of the first raw material powder) were added and ground evenly using an agate mortar. The powder was then placed in an alumina crucible and sintered for 5 hours at 1500℃ in an alumina tube furnace under a reducing atmosphere of 95% N₂ + 5% H₂. After cooling to room temperature in the furnace, the calcined product was ground to obtain the yellow fluorescent powder Y₃Al₅O₃. 12 Ce 3+ ; Weigh 1.89g of silicone rubber polydimethylsiloxane and 0.21g of ethylbenzene curing agent, mix them, and form a film raw material; Add 0.2g of yellow fluorescent powder to the film raw material, mix thoroughly in a vacuum centrifuge, place in an oven and pre-cur at 60℃ for 0.5h, then cure at 100℃ for 2h to obtain yellow fluorescent pigment.

[0032] Comparative Example 2 A commercial YAG fluorescent powder.

[0033] Test 1. Emission spectra of the mixed phosphor prepared in Example 1 and the yellow phosphor prepared in Comparative Example 1 were analyzed, and their emission spectra are compared as follows: Figure 1 As shown, the yellow composite fluorescent pigment prepared in Example 1 and the commercial YAG phosphor in Comparative Example 2 were analyzed by a spectrophotometer, and the comparative data are as follows: Figure 2 As shown.

[0034] Depend on Figure 1 It is evident that mechanically grinding and mixing the yellow and blue phosphors prepared in Example 1 to obtain a mixed phosphor does not improve the fluorescence emission intensity of the yellow phosphor. Figure 2 It can be seen that the fluorescence intensity of yellow phosphor increased by 15-30% after adding blue phosphor and film raw materials.

[0035] 2. The emission spectra of the yellow composite fluorescent pigments prepared in Examples 1-3 and the yellow fluorescent pigment prepared in Comparative Example 1 under blue light (near ultraviolet) excitation at a wavelength of 380 nm were analyzed. Their emission spectra are as follows: Figure 3 As shown.

[0036] Depend on Figure 3 It can be seen that as the amount of blue phosphor added increases, the enhanced yellow fluorescence shows a trend of first increasing and then decreasing. Therefore, a better doping ratio can be obtained for subsequent lighting applications that enhance luminous intensity.

[0037] 3. The yellow composite fluorescent pigments prepared in Examples 1-3 and the yellow fluorescent pigment prepared in Comparative Example 1 were tested under visible light (blue light) excitation conditions, and the results are as follows: Figure 4 As shown.

[0038] Depend on Figure 4 It can be seen that the yellow composite fluorescent samples with added blue phosphor in Examples 1 to 3 are significantly more yellow than the pure yellow phosphor in Comparative Example 1 under visible light.

[0039] 4. The yellow composite fluorescent pigments prepared in Examples 1-3 and the yellow fluorescent pigment prepared in Comparative Example 1 were tested under ultraviolet light excitation conditions, and the results were as follows: Figure 5 As shown.

[0040] Depend on Figure 5 It can be seen that the yellow composite fluorescent samples with added blue phosphor in Examples 1 to 3 have significantly stronger luminescence intensity under ultraviolet light than the pure yellow phosphor in Comparative Example 1.

[0041] 5. Color temperature adjustment analysis was performed on the yellow composite fluorescent pigments prepared in Examples 1 and 3. The results were obtained with reference to the CIE 1931 chromaticity diagram. Figure 6 As shown.

[0042] Depend on Figure 6 It can be seen that the color temperature can be adjusted by adjusting the mixing ratio of phosphors. Its emission color coordinates can be continuously adjusted in the range of (0.21, 0.18) to (0.19, 0.39) in the CIE1931 chromaticity diagram, indicating that its output light color coverage is relatively wide.

[0043] 6. Color stability analysis was performed on the yellow composite fluorescent pigment prepared in Example 1. The results of the relationship between luminescence intensity and wavelength under different pressure conditions are as follows: Figure 7 As shown.

[0044] Depend on Figure 7It can be seen that under pressure cycling conditions of 0~15GPa, after depressurization, its luminescence characteristics have good recoverability, and the recovery ability of key optical properties can reach more than 80%, demonstrating good color stability and cycling reliability.

[0045] Therefore, the present invention adopts the above-mentioned method for preparing a yellow composite fluorescent pigment that enhances luminescence intensity, which overcomes the problems of cold color temperature and low color rendering index of traditional yellow phosphors, improves the luminescence intensity of yellow phosphors, and expands their spectral response range.

[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a yellow composite fluorescent pigment to enhance luminescence intensity, characterized in that, Includes the following steps: S1. Preparation of yellow phosphor: According to the stoichiometric ratio of Ce-doped garnet structure phosphor, Y2O3, Al(NO3)3·9H2O and Ce(NO3)3·6H2O are taken as raw materials, mixed and ground to obtain the first raw material powder. BaF2 and NH4F are added to the first raw material powder, ground, sintered at 800~1500℃ in a reducing atmosphere for 1~12h, cooled in the furnace and ground to obtain yellow phosphor; S2. Preparation of blue phosphor: According to the chemical formula BaMgAl 10 O 17 Eu 2+ The stoichiometric ratio of each element in the mixture was determined by taking Ba(NO3)2, Mg(NO3)2·6H2O, Al(NO3)3·9H2O and Eu2O3 as raw materials, mixing and grinding them to obtain a second raw material powder. BaF2 and NH4F were added to the second raw material powder, and the mixture was ground. The powder was then sintered at 800~1500℃ in a reducing atmosphere for 1~12h, cooled in the furnace, and ground again to obtain a blue fluorescent powder. S3. Preparation of film raw materials: Take the main agent and curing agent at a mass ratio of 1~20:1, mix them, and obtain the film raw materials; S4. Composite and curing: Take the yellow phosphor obtained in S1 and the blue phosphor obtained in S2 at a mass ratio of 1:0.5~2, mix them to obtain a mixed phosphor, add the mixed phosphor to the film raw material obtained in S3, and treat it by high temperature solid-state method or hot injection method to obtain yellow composite fluorescent pigment.

2. The method for preparing a yellow composite fluorescent pigment with enhanced luminescence intensity according to claim 1, characterized in that, In S1, the Ce-doped garnet structure phosphor is specifically Y3Al5O 12 ∶Ce 3+ or (Y) 2.5 Ce 0.5 Al5O 12 .

3. The method for preparing a yellow composite fluorescent pigment with enhanced luminescence intensity according to claim 1, characterized in that, In S1, the amounts of BaF2 and NH4F added are 0.1 to 5% of the mass of the first raw material powder, respectively.

4. The method for preparing a yellow composite fluorescent pigment with enhanced luminescence intensity according to claim 1, characterized in that, In S2, the amounts of BaF2 and NH4F added are 0.1 to 5% of the mass of the second raw material powder, respectively.

5. The method for preparing a yellow composite fluorescent pigment with enhanced luminescence intensity according to claim 1, characterized in that, In S1 and S2, the reducing atmosphere consists of 95% N2 and 5% H2, by volume percentage.

6. The method for preparing a yellow composite fluorescent pigment with enhanced luminescence intensity according to claim 1, characterized in that, In S1 and S2, the refractive index range of both the yellow phosphor and the blue phosphor is 1.55~1.

60.

7. The method for preparing a yellow composite fluorescent pigment with enhanced luminescence intensity according to claim 1, characterized in that, In S3, the main agent is one or more of silicone rubber polydimethylsiloxane, epoxy resin, polycarbonate or acrylamide; The curing agent is one or more of ethylbenzene, vinyltriamine, and ethylenediamine; The refractive index of the thin film material is in the range of 1.5 to 1.

6.

8. The method for preparing a yellow composite fluorescent pigment with enhanced luminescence intensity according to claim 1, characterized in that, In S4, the high-temperature solid-state method specifically refers to: After being thoroughly mixed in a vacuum centrifuge, the mixture is pre-cured at 20~180℃ for 0.5~6h, and then cured at 100~300℃ for 0.5~10h to obtain a yellow composite fluorescent pigment. The amount of the mixed phosphor added is 5-50% of the mass of the film raw material.

9. A yellow composite fluorescent pigment prepared by the method for preparing a yellow composite fluorescent pigment with enhanced luminescence intensity as described in any one of claims 1 to 8.

10. A yellow composite fluorescent pigment for enhancing luminescence intensity according to claim 9, characterized in that: Under blue and ultraviolet light, the chromaticity coordinates of the yellow composite fluorescent pigment can be adjusted from (0.21, 0.18) to (0.19, 0.39).

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