High-efficiency narrow-band blue fluorescent material, preparation method and application thereof

Abstract

A high-efficiency narrow-band blue fluorescent material and its preparation method and application, relating to the field of fluorescent materials. The chemical formula of the fluorescent material is: Ba 2‑x Eu x Hf 2+y Si 5‑4y Al 2+4y O 19 , where 0<x≤0.05, 0.1≤y≤0.5. The crystal structure of the matrix corresponding to the material belongs to the hexagonal system, and the space group is P63 / m. 2+ As an activator, under the excitation of 400 nm purple light, the main peak of the emission spectrum is located at 455-475 nm, the half-maximum width is 70-80 nm, and the quantum efficiency is greater than 70%, so that the fluorescent material can be used in white light LED devices.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of fluorescent materials, in particular to a high-efficiency narrow-band blue fluorescent material and a preparation method and application thereof. BACKGROUND

[0002] As the most common lighting product, white LED light source has entered thousands of households. The most common way of white LED light source outputting white light is to use the light emitted by the LED chip to excite the fluorescent material, and the light emitted by the fluorescent material under excitation and the light (emitted by the LED) not absorbed by the fluorescent material are mixed to obtain white light. Obviously, the fluorescent material is the key to making white LED light source.

[0003] As a functional material, the performance parameters of the fluorescent material include the characteristics of the emission spectrum, the luminous intensity and the quantum efficiency, etc. In particular, the position of the main peak of the emission spectrum has a great influence on the light color and electrical quality of the white LED, so the regulation of the emission spectrum of the fluorescent material is particularly important. Common methods for regulating the emission spectrum, such as disclosed in patent document 2 (Mao Zhiyong, Chen Jingjing, Wang Dajian, Lu Zhijuan, Xu Jiao, Yang Yanfang, A crystal form regulated multi-color fluorescent material and a preparation method and application thereof, CN105238396A), can achieve the regulation of the emission spectrum of the fluorescent material by changing the crystal form; as disclosed in patent document 3 (Wu Zhanchao, Huang Chong, Liu Jie, A novel spectrum-adjustable self-activated fluorescent powder, CN108251112B), the emission spectrum is regulated by adjusting the crystal field; as disclosed in patent document 4 (Pan Zaifa, Wang Lili, Liu Shuang, Mo Weimin, A single-matrix white fluorescent powder for white LED and a preparation method thereof, CN102559179A), the spectrum is regulated by adjusting the proportion of different light centers and relying on the energy transfer between the light centers.

[0004] Under normal circumstances, the direction of spectrum regulation is one-way. That is, by changing the regulation parameters, the emission spectrum of the fluorescent material will move in a certain direction (for example, the long-wavelength direction such as red light; or the short-wavelength direction such as blue light). As disclosed in patent document 5 (Ye Qiaowen, Liu Ruxi, Adjustable fluorescent powder for light emission, CN102734752B), a spectrum-adjustable nitride fluorescent material with the chemical formula (AE)Si 6-p Al pN8, wherein AE is an alkaline earth metal and a doped rare earth element RE, p is a parameter defining the relative aluminum content by weight and p is greater than zero. As the value of p increases, the main peak of the emission spectrum of the fluorescent material can be adjusted from the blue light region (452 nm) to the red light region (604 nm); as disclosed in patent document 6 (Liu Ronghui, Qin Shaowei, Liu Yuanhong, Li Yanfeng, Chen Xiaoxia, Ma Xiaole, Xue Yuan, A garnet structure fluorescent powder and a light emitting device comprising the same, disclosed a kind of CN113416544B) A spectrum adjustable garnet structure fluorescent material, the fluorescent material contains 38.47%-45.19% of Y element by weight, 9.49%-22.09% of Al element, 2.06%-24.31% of Ga element, 27.3%-32.04% of O element, 0.43%-1.46% of Ce element. As the Ga content increases, the main peak of the emission spectrum of the fluorescent material can be adjusted from 531 nm to 517 nm.

[0005] Defects are ubiquitous in materials. For fluorescent materials, common defects are point defects, including vacancies and interstitial atoms, etc. For fluorescent materials, as disclosed in non-patent document 1 (Xin Pan, Lefu Mei, Yixi Zhuang, Takatoshi Seto, Yuhua Wang, Mikhail Plyaskin, Wei Xi, Chao Li, Qingfeng Guo, Libing Liao, Anti-Defect engineering toward high luminescent efficiency in whitlockite phosphors), the presence of defects can significantly reduce the luminescent performance (such as quantum efficiency) of the fluorescent material, so defects should be avoided as much as possible during the synthesis of the fluorescent material.

[0006] In summary, it is currently generally believed that the emission spectrum of a fluorescent material is unidirectionally adjustable, and defects in the fluorescent material should be avoided as much as possible. The present application deliberately creates defects in a fluorescent material of the chemical formula Ba 2-x Eu x Hf 2+y Si 5-4y Al 2+4y O 19 (wherein, 0 19The crystal structure of the fluorescent material (Ba1-xEux)2Si5Al2O16 belongs to hexagonal system, and the space group is P63 / m. The high-efficiency, narrow-band and blue light emitting behavior of the fluorescent material is disclosed for the first time. SUMMARY

[0007] The present application aims to solve the above problems in the prior art, and provides a high-efficiency narrow-band blue fluorescent material, a preparation method and application thereof. Under the excitation of 400 nm violet light, the main peak of the emission spectrum of the high-efficiency narrow-band blue fluorescent material is located at 455-475 nm, the half-height width of the emission spectrum is 70-80 nm, and the quantum efficiency is > 70%.

[0008] To this end, the first object of the present application is to provide a high-efficiency narrow-band blue fluorescent material.

[0009] A high-efficiency narrow-band blue fluorescent material, which can be represented by the following chemical formula:

[0010] Ba 2-x Eu x Hf 2+y Si 5-4y Al 2+4y O 19

[0011] wherein 0

[0012] Preferably, the x can be 0.03, and the y can be 0.3.

[0013] The second object of the present application is to provide a preparation method of a high-efficiency narrow-band blue fluorescent material. The preparation method comprises the following steps: mixing Ba precursor, Eu precursor, Hf precursor, Si precursor and Al precursor, and performing high-temperature solid-phase reaction under a reducing atmosphere to obtain a high-efficiency narrow-band blue fluorescent material.

[0014] Preferably, the molar ratio of Ba, Eu, Hf, Si and Al in the Ba precursor, Eu precursor, Hf precursor, Si precursor and Al precursor is (2-x):x:(2+y):(5-4y):(2+4y), wherein 0

[0015] Preferably, the Ba precursor is selected from one or more of carbonates of Ba, oxides of Ba, oxalates of Ba and nitrates of Ba; the Eu precursor is selected from one or more of carbonates of Eu, oxides of Eu, oxalates of Eu and nitrates of Eu; the Hf precursor is selected from HfO2; the Si precursor is selected from SiO2; and the Al precursor is selected from one or more of carbonates of Al, oxides of Al, oxalates of Al and nitrates of Al.

[0016] Preferably, the purity of the Ba precursor, Eu precursor, Hf precursor, Si precursor and Al precursor is not less than 99.5%.

[0017] Preferably, the temperature of the high-temperature solid-phase reaction is 1400-1600° C., the atmosphere is a reducing atmosphere, and the time of the high-temperature solid-phase reaction is 4-10 hours.

[0018] Another object of the present invention is to provide a white light LED device. The white light LED device comprises a high efficiency narrow band blue fluorescent material (whose chemical formula is: Ba 2-x Eu x Hf 2+y Si 5-4y Al 2+4y O 19 , where 0<x≤0.05, 0.1≤y≤0.5) and the main peak of the emission spectrum is located between 380 and 425 nm.

[0019] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0020] By deliberately creating (interstitial atom) defects within the fluorescent material, the present invention unexpectedly modulates the main peak position of the fluorescent material's emission spectrum, while significantly enhancing the quantum efficiency of the fluorescent material. Ultimately, the present invention provides a highly efficient narrow-band blue fluorescent material with a completely new crystal structure. The chemical formula of the fluorescent material is: Ba 2-x Eu x Hf 2+ y Si 5-4y Al 2+4y O 19 , where 0<x≤0.05, 0.1≤y≤0.5. The matrix corresponding to the fluorescent material (Ba2Hf2Si5Al2O 19 ) belongs to the hexagonal crystal system, and the space group is P63 / m. 2+ It is the luminescence center, with the strongest excitation peak located near 400 nm, the main peak of the emission spectrum located at 455-475 nm, the half-maximum width in the range of 70-80 nm, and the quantum efficiency >70%, so that the fluorescent material can be used in the packaging of white light LED devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 : is the emission spectrum of the material obtained in Comparative Example 1 under 400 nm excitation.

[0022] Figure 2 This is the emission spectrum of the material obtained in Comparative Example 4 under 400 nm excitation.

[0023] Figure 3 Excitation and emission spectra of the material obtained in Example 1.

[0024] Figure 4 X-ray diffraction pattern of the material obtained in Example 1.

[0025] Figure 5 Crystal structure of the material (corresponding to the matrix) obtained in Example 1.

[0026] Figure 6 Variation of the luminescent properties of the material obtained in Examples 1-5.

[0027] Figure 7 Variation of the luminescent properties of the material obtained in Examples 6-10.

[0028] Figure 8 Variation of the luminescent properties of the material obtained in Examples 11-15.

[0029] Figure 9 Variation of the luminescent properties of the material obtained in Examples 16-20.

[0030] Figure 10 Variation of the luminescent properties of the material obtained in Examples 21-25.

[0031] Figure 11 Variation of the luminescent properties of the material obtained in Examples 26-30.

[0032] Figure 12 Spectrum of the white LED device obtained in Example 31. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the embodiments of the present application.

[0034] For the purpose of understanding the present application, the following embodiments are listed. It should be understood by those skilled in the art that the embodiments are only used to help understand the present application, and should not be regarded as specific limitation to the present application.

[0035] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below in conjunction with the embodiments.

[0036] The present application proposes a high-efficiency narrow-band blue fluorescent material, which can be expressed by the following chemical formula:

[0037] Ba 2-x Eu x Hf 2+y Si 5-4y Al2+4y O 19 ,

[0038] wherein 0 < x ≤ 0.05, 0.1 ≤ y ≤ 0.5.

[0039] In the embodiments 1-5 of the present application, x is preferably 0.005, y is preferably 0.1, 0.2, 0.3, 0.4 and 0.5; in the embodiments 6-10 of the present application, x is preferably 0.01, y is preferably 0.1, 0.2, 0.3, 0.4 and 0.5; in the embodiments 11-15 of the present application, x is preferably 0.02, y is preferably 0.1, 0.2, 0.3, 0.4 and 0.5; in the embodiments 16-20 of the present application, x is preferably 0.03, y is preferably 0.1, 0.2, 0.3, 0.4 and 0.5; in the embodiments 21-25 of the present application, x is preferably 0.04, y is preferably 0.1, 0.2, 0.3, 0.4 and 0.5; in the embodiments 26-30 of the present application, x is preferably 0.05, y is preferably 0.1, 0.2, 0.3, 0.4 and 0.5.

[0040] The present application also provides a preparation method of the high-efficiency narrow-band blue fluorescent material, which comprises the following steps: mixing Ba precursor, Eu precursor, Hf precursor, Si precursor and Al precursor, and performing high-temperature solid-phase reaction under a reducing atmosphere to obtain the high-efficiency narrow-band blue fluorescent material.

[0041] In the above step, the molar ratio of Ba, Eu, Hf, Si and Al in the Ba precursor, the Eu precursor, the Hf precursor, the Si precursor and the Al precursor is (2-x):x:(2+y):(5-4y):(2+4y), wherein 0 < x ≤ 0.05, 0.1 ≤ y ≤ 0.5.

[0042] In the above step, the Ba precursor can be any compound containing Ba known in the art without special limitation, and in the present application, it is preferably one or more of carbonates of Ba, oxides of Ba, oxalates of Ba and nitrates of Ba, and more preferably carbonates of Ba, i.e. BaCO3; the Eu precursor can be selected from one or more of carbonates of Eu, oxides of Eu, oxalates of Eu and nitrates of Eu, and more preferably oxides of Eu, i.e. Eu2O3; the Hf precursor is selected from HfO2; the Si precursor is selected from SiO2; and the Al precursor can be any compound containing Al known in the art without special limitation, and in the present application, it is preferably one or more of carbonates of Al, oxides of Al, oxalates of Al and nitrates of Al, and more preferably oxides of Al, i.e. Al2O3.

[0043] The purity of the Ba precursor, the Eu precursor, the Hf precursor, the Si precursor and the Al precursor is not less than 99.5%, and the higher the purity, the less the impurities of the obtained fluorescent powder.

[0044] The temperature of the high-temperature solid phase in the above step is preferably 1400-1600°C, and the atmosphere is a reducing atmosphere; in some embodiments provided by the present application, the temperature of the high-temperature solid phase is preferably 1500°C; the reducing atmosphere can be any reducing atmosphere known to those skilled in the art, and is not particularly limited, and in the present application, a nitrogen-hydrogen mixed atmosphere with a volume ratio of 9:1 is preferred.

[0045] The time of the high-temperature solid phase in the above step is preferably 4-10h, and more preferably 5-8h; in some embodiments provided by the present application, the time of the high-temperature solid phase is preferably 6h.

[0046] The high-temperature solid phase reaction in the above step is preferably carried out in a high-temperature furnace; after the reaction is carried out, the furnace is cooled to room temperature, and a high-efficiency narrow-band blue fluorescent material is obtained.

[0047] The high-temperature solid phase reaction in the above step is preferably carried out in a high-temperature furnace; after the reaction is carried out, the furnace is cooled to room temperature, and a high-efficiency narrow-band blue fluorescent material is obtained.

[0048] The present application also provides a white light LED device. The white light LED device at least comprises Ba 2-x Eu x Hf 2+y Si 5-4y Al 2+ 4y O 19 , (wherein 0

[0049] In order to further illustrate the present application, a high-efficiency narrow-band blue fluorescent material and a preparation method thereof provided by the present application are described in detail below with reference to the examples.

[0050] The reagents used in the following comparative examples and examples are commercially available.

[0051] Comparative Example 1

[0052] The raw materials are BaCO3, Eu2O3, HfO2, SiO2 and Al2O3. The molar ratio of Ba, Eu, Hf, Si and Al in BaCO3, Eu2O3, HfO2, SiO2 and Al2O3 is 1.97:0.03:2:5:2. After grinding and mixing, the above raw materials are put into a crucible and sintered at 1500℃ for 6h in a high temperature furnace under a 9:1 nitrogen and hydrogen mixed atmosphere. After cooling to room temperature, the theoretical chemical composition is Ba 1.97 Eu 0.03 Hf2Si5Al2O 19 materials.

[0053] The material obtained in Comparative Example 1 has no (significant) defects. This is because although Eu replaces Ba, the charge number is the same, the radius is close, and the amounts of all elements are configured according to the stoichiometric ratio. Therefore, in theory, the material obtained in Comparative Example 1 should have a higher quantum efficiency. This is indeed the case. The luminescence properties of the corresponding material in Comparative Example 1 were analyzed using a fluorescence spectrometer, as shown in Figure 2. Figure 1 As shown. The results show that the main peak of the emission spectrum of the material obtained in Comparative Example 1 is located at 510 nm, which is cyan light, and the half-height width of the emission spectrum is 85 nm. The quantum efficiency of the material corresponding to Comparative Example 1 was tested using a quantum efficiency tester. The results show that the quantum efficiency of the material obtained in Comparative Example 1 is 77.3%, which is an extremely high value. Specific data are shown in Table 1. Since there are no defects, although the material obtained in Comparative Example 1 is not a blue luminescent material, its luminescence performance is excellent.

[0054] That is, Comparative Example 1 is a cyan luminescent material with excellent performance.

[0055] Comparative Example 2

[0056] The raw materials are BaCO3, Eu2O3, HfO2, SiO2 and Al2O3. The molar ratio of Ba, Eu, Hf, Si and Al in BaCO3, Eu2O3, HfO2, SiO2 and Al2O3 is 1.97:0.03:2.6:2.6:4.4. After grinding and mixing the above raw materials, they are put into a crucible and sintered at 1500℃ for 6h in a high temperature furnace under a 9:1 nitrogen and hydrogen mixed atmosphere. After cooling to room temperature, the theoretical chemical composition is Ba 1.97 Eu 0.03 Hf 2.6 Si 2.6 Al 4.4 O 19 materials.

[0057] Reference matrix chemical formula: Ba2Hf2Si5Al2O 19 , considering that Si and Al occupy the same crystallographic position (see Figure 5), the material obtained in Comparative Example 2 obviously has high concentration (30%) of interstitial defects of Hf (Eu replaces Ba, but has the same charge number and close radius, so the defect effect is not obvious). Therefore, theoretically, the luminescent performance of the material obtained in Comparative Example 2 should be poor. In fact, it is also the case. The luminescent performance of the material corresponding to Comparative Example 2 was analyzed by using a fluorescence spectrometer. The results show that the main peak of the emission spectrum of the material obtained in Comparative Example 2 is located at 511 nm, which is cyan green light, and the half-height width of the emission spectrum is 82 nm. Obviously, the performance of the emission spectrum of the material obtained in Comparative Example 2 is similar to that of Comparative Example 1. The quantum efficiency of the material corresponding to Comparative Example 2 was tested by using a quantum efficiency tester. The results show that the quantum efficiency of the material obtained in Comparative Example 2 is only 16.5%, which is extremely low. The specific data are shown in Table 1. Obviously, due to the artificial interstitial defects of Hf, the luminescent performance (quantum efficiency) of the material obtained in Comparative Example 2 obviously decreases compared with that of Comparative Example 1.

[0058] That is, Comparative Example 2 is a cyan green luminescent material with poor performance.

[0059] Comparative Example 3

[0060] The raw materials are BaC03, Eu203, Hf02, Si02and Al203, and the molar ratio of Ba, Eu, Hf, Si and Al in BaC03, Eu203, Hf02, Si02and Al203is 1.97:0.03:2.05:4.8:2.2. After the above raw materials are ground and uniformly mixed, they are loaded into a crucible, and then sintered at 1500°C for 6h in a high-temperature furnace under a mixed gas atmosphere of 9:1 nitrogen and hydrogen, and cooled to room temperature in the furnace to obtain a material with a theoretical chemical composition of Ba 1.97 Eu 0.03 Hf 2.05 Si 4.8 Al 2.2 O 19 .

[0061] The control matrix chemical formula is Ba2Hf2Si5Al2O 19, considering that Si and Al occupy the same crystallographic position, the material obtained in Comparative Example 3 apparently has a lower concentration (2.5%) of interstitial defects of Hf (Eu replaces Ba, but the charge number is the same and the radius is close, so the defect effect is not obvious). Therefore, theoretically, the luminescent performance of the material obtained in Comparative Example 3 should be poorer (but better than that of Comparative Example 2). This is also true. The luminescent performance of the corresponding material in Comparative Example 3 was analyzed using a fluorescence spectrometer. The results showed that the main peak of the emission spectrum of the material obtained in Comparative Example 3 was located at 510 nm, which was cyan green light, and the half-height width of the emission spectrum was 80 nm. Apparently, the performance of the emission spectrum of the material obtained in Comparative Example 3 was similar to that of Comparative Examples 1 and 2. The quantum efficiency of the corresponding material in Comparative Example 3 was tested using a quantum efficiency tester. The results showed that the quantum efficiency of the material obtained in Comparative Example 3 was 53.4%, which was ordinary but obviously improved compared with Comparative Example 2. The specific data are shown in Table 1. Apparently, due to the interstitial Hf (although the defect concentration is very low), the luminescent performance (quantum efficiency) of the material obtained in Comparative Example 3 decreased to some extent compared with Comparative Example 1.

[0062] That is, Comparative Example 3 is an ordinary cyan green luminescent material.

[0063] Comparative Example 4

[0064] The raw materials were BaCO3, Eu2O3, HfO2, SiO2and Al2O3, and the molar ratio of Ba, Eu, Hf, Si and Al in BaCO3, Eu2O3, HfO2, SiO2and Al2O3was 1.97:0.03:2:4.775:2.3. After the above raw materials were ground and uniformly mixed, they were loaded into a crucible, and then sintered at 1500°C for 6h in a high-temperature furnace under a nitrogen-hydrogen mixed gas atmosphere of 9:1, and then cooled to room temperature in the furnace to obtain a material with a theoretical chemical composition of Ba 1.97 Eu 0.03 Hf2Si 4.775 Al 2.3 O 19 .

[0065] The control matrix chemical formula is Ba2Hf2Si5Al2O 19 . Compared with Comparative Examples 2 and 3, apparently, there are no interstitial defects of Hf in Comparative Example 4. However, although Si and Al occupy the same crystallographic position, the ratio of Si and Al is different, which will inevitably affect the optical band gap and luminescent performance of the material. This is also true. The luminescent performance of the corresponding material in Comparative Example 4 was analyzed using a fluorescence spectrometer, and the results are shown in Table 1. Figure 2The results show that the main peak of the emission spectrum of the material obtained from Comparative Example 4 is located at 496 nm, which is cyan light, and the half-height width of the emission spectrum is 79 nm. Obviously, the performance of the emission spectrum of the material obtained from Comparative Example 4 is obviously different from that of Comparative Example 1 due to the adjustment of the relative proportions of Si and Al. The quantum efficiency of the material corresponding to Comparative Example 4 is tested by using a quantum efficiency tester. The results show that the quantum efficiency of the material obtained from Comparative Example 4 is 52.5%. The specific data are shown in Table 1. Obviously, without obvious defects, only the proportions of Si and Al are changed, which eventually leads to a certain degree of decrease in the luminescent performance (quantum efficiency) of the material obtained from Comparative Example 4 compared with that of Comparative Example 1, and the difference in the emission spectrum is also obvious.

[0066] That is, Comparative Example 4 is a cyan luminescent material with ordinary performance.

[0067] Comparative Example 5

[0068] The raw materials are BaCO3, Eu2O3, HfO2, SiO2and Al2O3, and the molar ratio of Ba, Eu, Hf, Si and Al in BaCO3, Eu2O3, HfO2, SiO2and Al2O3 is 1.97:0.03:1.775:5:2.3. After the above raw materials are ground and uniformly mixed, they are loaded into a crucible, and then sintered at 1500°C for 6h in a high-temperature furnace under a mixed atmosphere of nitrogen and hydrogen at a ratio of 9:1, and then cooled to room temperature in the furnace to obtain a material with a theoretical chemical composition of Ba 1.97 Eu 0.03 Hf 1.775 Si5Al 2.3 O 19 .

[0069] The control matrix chemical formula is Ba2Hf2Si5Al2O 19 Comparative Example 5 increases the vacancy defects of Hf and the interstitial defects of Al. Therefore, theoretically, the luminescent performance of the material prepared in Comparative Example 5 should be poor. This is also true. The luminescent performance of the material corresponding to Comparative Example 5 is analyzed by using a fluorescence spectrometer. The results show that the main peak of the emission spectrum of the material obtained from Comparative Example 5 is located at 493 nm, which is cyan light, and the half-height width of the emission spectrum is 78 nm. Obviously, the performance of the emission spectrum of the material obtained from Comparative Example 5 is similar to that of Comparative Example 4. The quantum efficiency of the material corresponding to Comparative Example 5 is tested by using a quantum efficiency tester. The results show that the quantum efficiency of the material obtained from Comparative Example 5 is only 11.9%, which is extremely low. The specific data are shown in Table 1. Obviously, due to the artificial creation of vacancy defects of Hf and the increase of interstitial defects of Al, the luminescent performance (quantum efficiency) of the material obtained from Comparative Example 5 is obviously decreased compared with that of Comparative Example 4.

[0070] That is, Comparative Example 5 is a cyan luminescent material with poor performance.

[0071] Comparative Example 6

[0072] The raw materials were BaCO3, Eu2O3, HfO2, SiO2and Al2O3, and the molar ratio of Ba, Eu, Hf, Si and Al in BaCO3, Eu2O3, HfO2, SiO2and Al2O3was 1.97:0.03:2.3:4.7:2. The above raw materials were ground and mixed uniformly, then loaded into a crucible, and sintered at 1500°C for 6h in a high-temperature furnace under a mixed nitrogen-hydrogen atmosphere of 9:1, and cooled to room temperature in the furnace to obtain a material with a theoretical chemical composition of Ba 1.97 Eu 0.03 Hf 2.3 Si 4.7 Al2O 19 .

[0073] The control matrix chemical formula was Ba2Hf2Si5Al2O 19 Comparative Example 6 increased the interstitial defects of Hf, and also increased the vacancy defects of Si. Therefore, theoretically, the luminescent performance of the material obtained in Comparative Example 6 should be poor. This was also the case. The luminescent performance of the corresponding material in Comparative Example 6 was analyzed using a fluorescence spectrometer. The results showed that the main peak of the emission spectrum of the material obtained in Comparative Example 6 was located at 505 nm, which was cyan-green light, and the half-height width of the emission spectrum was 88 nm. Obviously, the performance of the emission spectrum of the material obtained in Comparative Example 6 was similar to that of Comparative Example 1. The quantum efficiency of the material corresponding to Comparative Example 6 was tested using a quantum efficiency tester. The results showed that the quantum efficiency of the material obtained in Comparative Example 6 was only 33.7%, which was extremely low. The specific data are shown in Table 1. Obviously, due to the artificial creation of interstitial defects of Hf and the increase of vacancy defects of Si, the luminescent performance (quantum efficiency) of the material obtained in Comparative Example 6 decreased significantly compared with Comparative Example 1.

[0074] That is, Comparative Example 6 was a cyan-green luminescent material with poor performance.

[0075] Examples 1-5

[0076] The raw materials are BaCO3, Eu2O3, HfO2, SiO2and Al2O3, and the molar ratio of Ba, Eu, Hf, Si and Al in BaCO3, Eu2O3, HfO2, SiO2and Al2O3is 1.995:0.005:2.1:4.6:2.4 (Example 1), 1.995:0.005:2.2:4.2:2.8 (Example 2), 1.995:0.005:2.3:3.8:3.2 (Example 3), 1.995:0.005:2.4:3.4:3.6 (Example 4), 1.995:0.005:2.5:3:4 (Example 5). After the above raw materials are ground and uniformly mixed, they are respectively loaded into a crucible, and sintered at 1500°C for 6h in a high-temperature furnace under a 9:1 nitrogen-hydrogen mixed gas atmosphere, and cooled to room temperature in the furnace to obtain materials with the following theoretical chemical compositions:

[0077] Ba 1.995 Eu 0.005 Hf 2.1 Si 4.6 Al 2.4 O 19 (Example 1)

[0078] Ba 1.995 Eu 0.005 Hf 2.2 Si 4.2 Al 2.8 O 19 (Example 2)

[0079] Ba 1.995 Eu 0.005 Hf 2.3 Si 3.8 Al 3.2 O 19 (Example 3)

[0080] Ba 1.995 Eu 0.005 Hf 2.4 Si 3.4 Al 3.6 O 19 (Example 4)

[0081] Ba 1.995 Eu 0.005 Hf 2.5 Si3Al4O 19 (Example 5)

[0082] Control matrix chemical formula: Ba2Hf2Si5Al2O 19, Example 1 increases the interstitial defects of Hf, while adjusting the ratio of Si and Al (although Si and Al occupy the same crystallographic position, the ratio of Si and Al is different, which will inevitably affect the optical band gap and luminescent performance of the material). Referring to Comparative Examples 2-4, theoretically, the luminescent performance of the material obtained in Example 1 should be poor, but in fact, the opposite is true. The corresponding phosphor in Example 1 was analyzed using a fluorescence spectrometer, and the excitation and emission spectrum diagrams were obtained as shown in Figure 3 . The material can absorb ultraviolet-violet light, and under 400 nm violet light excitation, the emission spectrum main peak is located at 459 nm, and the half-height width of the emission spectrum is 70 nm. The quantum efficiency of the material was tested using a quantum efficiency tester, and the value was 70.3%, as shown in Table 1. The quantum efficiency value is extremely high, indicating that the material has extremely high packaging practical value. The structure of the material obtained in Example 1 was analyzed by X-ray diffraction using an X-ray diffractometer, and the diffraction spectrum is shown in Figure 4 . By comparing the powder structure database, the diffraction data is completely different from the diffraction spectrum of the known fluorescent material, which shows that the material obtained in Example 1 is a fluorescent material with a completely new structure. Through single crystal diffraction analysis combined with powder structure refinement data, it is shown that the crystal structure of the material (matrix, Ba2Hf2Si5Al2O 19 ) belongs to hexagonal system, space group P63 / m, Figure 5 The crystal structure diagram of the material (matrix) is given.

[0083] Under the excitation of 400 nm violet light, the emission spectrum main peaks of Examples 2-5 are located at 457 nm (Example 2), 457 nm (Example 3), 456 nm (Example 4), and 455 nm (Example 5), and the half-height width of the emission spectrum is 70 nm (Example 2), 71 nm (Example 3), 72 nm (Example 4), and 73 nm (Example 5), and the quantum efficiency is 76.1% (Example 2), 77.7% (Example 3), 79.8% (Example 4), and 80.8% (Example 5), as shown in Table 1. Similar to Example 1, the luminescent performance of the materials obtained in Examples 2-5 is also excellent. Figure 6 The luminescent performance change diagram of the materials obtained in Examples 1-5 is given.

[0084] It can be seen that the materials obtained in Examples 1-5 are a high-efficiency narrow-band blue fluorescent material, which emits a spectrum main peak at 455-475 nm, a half-height width in the range of 70-80 nm, and a quantum efficiency > 70% under the excitation of 400 nm violet light, so that the fluorescent material can be applied to white light LED devices.

[0085] Examples 6-10

[0086] The raw materials are BaCO3, Eu2O3, HfO2, SiO2and Al2O3, and the molar ratio of Ba, Eu, Hf, Si and Al in BaCO3, Eu2O3, HfO2, SiO2and Al2O3is 1.99:0.01:2.1:4.6:2.4 (Example 6), 1.99:0.01:2.2:4.2:2.8 (Example 7), 1.99:0.01:2.3:3.8:3.2 (Example 8), 1.99:0.01:2.4:3.4:3.6 (Example 9), 1.99:0.01:2.5:3:4 (Example 10). The above raw materials are ground and mixed uniformly, and then are respectively loaded into a crucible. Under a mixed gas atmosphere of nitrogen and hydrogen at a ratio of 9:1, the crucible is sintered at 1500°C for 6h in a high-temperature furnace, and is cooled to room temperature in the furnace. The material with the following theoretical chemical composition is obtained:

[0087] Ba 1.99 Eu 0.01 Hf 2.1 Si 4.6 Al 2.4 O 19 (Example 6)

[0088] Ba 1.99 Eu 0.01 Hf 2.2 Si 4.2 Al 2.8 O 19 (Example 7)

[0089] Ba 1.99 Eu 0.01 Hf 2.3 Si 3.8 Al 3.2 O 19 (Example 8)

[0090] Ba 1.99 Eu 0.01 Hf 2.4 Si 3.4 Al 3.6 O 19 (Example 9)

[0091] Ba 1.99 Eu 0.01 Hf 2.5 Si3Al4O 19 (Example 10)

[0092] Chemical formula of the control matrix: Ba2Hf2Si5Al2O 19, embodiments 6-10 increased the interstitial defects of Hf, while adjusting the ratio of Si and Al (although Si and Al occupy the same crystallographic position, the ratio of Si and Al is different, which will inevitably affect the optical band gap and luminescent properties of the material). Referring to Comparative Examples 2-4, theoretically, the luminescent properties of the materials obtained in embodiments 6-10 should be poor, but in fact, the opposite is true. The corresponding phosphor in embodiments 6-10 was analyzed using a fluorescence spectrometer. The results showed that the materials corresponding to embodiments 6-10 could absorb ultraviolet-violet light, and under 400 nm violet light excitation, the emission spectrum main peak was located at 461 nm (Example 6), 460 nm (Example 7), 459 nm (Example 8), 458 nm (Example 9) and 458 nm (Example 10), and the half-height width of the emission spectrum was 73 nm (Example 6), 74 nm (Example 7), 72 nm (Example 8), 73 nm (Example 9) and 74 nm (Example 10). The quantum efficiency of Examples 6-10 was tested using a quantum efficiency tester, and the values were 75.9% (Example 6), 79.2% (Example 7), 80.1% (Example 8), 82.9% (Example 9) and 83.1% (Example 10), as shown in Table 1. The quantum efficiency value is extremely high, indicating that the material has extremely high packaging practical value. The structure of the material obtained in Examples 6-10 was analyzed by X-ray diffraction using an X-ray diffractometer, and the results were basically the same as those of Example 1. Figure 7 A graph showing the change in luminescent properties of the material obtained in embodiments 6-10 is given.

[0093] As can be seen, the material obtained in embodiments 6-10 is a high-efficiency narrow-band blue fluorescent material, which emits a spectrum with a main peak at 455-475 nm and a half-height width in the range of 70-80 nm under 400 nm violet light excitation, and the quantum efficiency is >70%, so that the fluorescent material can be applied to white light LED devices.

[0094] Examples 11-15

[0095] The raw materials are BaCO3, Eu2O3, HfO2, SiO2and Al2O3, and the molar ratio of Ba, Eu, Hf, Si and Al in BaCO3, Eu2O3, HfO2, SiO2and Al2O3is 1.98:0.02:2.1:4.6:2.4 (Example 11), 1.98:0.02:2.2:4.2:2.8 (Example 12), 1.98:0.02:2.3:3.8:3.2 (Example 13), 1.98:0.02:2.4:3.4:3.6 (Example 14), 1.98:0.02:2.5:3:4 (Example 15). The above raw materials are ground and mixed uniformly, and then are respectively loaded into a crucible. Under a mixed gas atmosphere of nitrogen and hydrogen at a ratio of 9:1, the crucible is sintered at 1500°C for 6h in a high-temperature furnace, and is cooled to room temperature in the furnace. The material with the following theoretical chemical composition is obtained:

[0096] Ba 1.98 Eu 0.02 Hf 2.1 Si 4.6 Al 2.4 O 19 (Example 11)

[0097] Ba 1.98 Eu 0.02 Hf 2.2 Si 4.2 Al 2.8 O 19 (Example 12)

[0098] Ba 1.98 Eu 0.02 Hf 2.3 Si 3.8 Al 3.2 O 19 (Example 13)

[0099] Ba 1.98 Eu 0.02 Hf 2.4 Si 3.4 Al 3.6 O 19 (Example 14)

[0100] Ba 1.98 Eu 0.02 Hf 2.5 Si3Al4O 19 (Example 15)

[0101] The control matrix chemical formula is: Ba2Hf2Si5Al2O 19, the proportion of Si and Al was adjusted (although Si and Al occupy the same crystallographic position, but the proportion of Si and Al is different, which will inevitably affect the optical band gap and luminescence performance of the material). Referring to Comparative Examples 2-4, theoretically, the luminescence performance of the materials obtained in Examples 11-15 should be poor, but in fact, the opposite is true. The corresponding phosphor in Examples 11-15 was analyzed by a fluorescence spectrometer. The results showed that the materials corresponding to Examples 11-15 could absorb ultraviolet-violet light, and under 400 nm violet light excitation, the emission spectrum main peak was located at 467 nm (Example 11), 462 nm (Example 12), 465 nm (Example 13), 464 nm (Example 14) and 460 nm (Example 15), and the half-height width of the emission spectrum was 75 nm (Example 11), 77 nm (Example 12), 76 nm (Example 13), 73 nm (Example 14) and 73 nm (Example 15). The quantum efficiency of Examples 11-15 was tested using a quantum efficiency tester, and the values were 76.4% (Example 11), 78.9% (Example 12), 79.6% (Example 13), 80.4% (Example 14) and 88.2% (Example 15), as shown in Table 1. The quantum efficiency value is extremely high, indicating that the material has extremely high packaging practical value. The structure of the material obtained in Examples 11-15 was analyzed by X-ray diffraction using an X-ray diffractometer, and the results were basically the same as those of Example 1. Figure 8 The luminescence performance of the material obtained in Examples 11-15 is shown in the following graph.

[0102] It can be seen that the material obtained in Examples 11-15 is a high-efficiency narrow-band blue fluorescent material, which emits a spectrum main peak at 455-475 nm under 400 nm violet light excitation, and the half-height width is in the range of 70-80 nm, and the quantum efficiency is >70%, so that the fluorescent material can be applied to white light LED devices.

[0103] Examples 16-20

[0104] The raw materials are BaCO3, Eu2O3, HfO2, SiO2and Al2O3, and the molar ratio of Ba, Eu, Hf, Si and Al in BaCO3, Eu2O3, HfO2, SiO2and Al2O3is 1.97:0.03:2.1:4.6:2.4 (Example 16), 1.97:0.03:2.2:4.2:2.8 (Example 17), 1.97:0.03:2.3:3.8:3.2 (Example 18), 1.97:0.03:2.4:3.4:3.6 (Example 19), 1.97:0.03:2.5:3:4 (Example 20). The above raw materials are ground and mixed uniformly, and then are respectively loaded into a crucible. Under a mixed gas atmosphere of nitrogen and hydrogen at a ratio of 9:1, the crucible is sintered at 1500°C for 6h in a high-temperature furnace, and is cooled to room temperature in the furnace. Materials with the following theoretical chemical compositions are obtained:

[0105] Ba 1.97 Eu 0.03 Hf 2.1 Si 4.6 Al 2.4 O 19 (Example 16)

[0106] Ba 1.97 Eu 0.03 Hf 2.2 Si 4.2 Al 2.8 O 19 (Example 17)

[0107] Ba 1.97 Eu 0.03 Hf 2.3 Si 3.8 Al 3.2 O 19 (Example 18)

[0108] Ba 1.97 Eu 0.03 Hf 2.4 Si 3.4 Al 3.6 O 19 (Example 19)

[0109] Ba 1.97 Eu 0.03 Hf 2.5 Si3Al4O 19 (Example 20)

[0110] Chemical formula of the control matrix: Ba2Hf2Si5Al2O 19, embodiments 16-20 increased the interstitial defects of Hf, while adjusting the ratio of Si and Al (although Si and Al occupy the same crystallographic position, the ratio of Si and Al is different, which will inevitably affect the optical band gap and luminescent performance of the material). Referring to Comparative Examples 2-4, theoretically, the luminescent performance of the materials obtained in embodiments 16-20 should be poor, but in fact, the opposite is true. The corresponding phosphor in embodiments 16-20 was analyzed using a fluorescence spectrometer. The results showed that the materials corresponding to embodiments 16-20 could absorb ultraviolet-violet light, and under 400 nm violet light excitation, the emission spectrum main peak was located at 470 nm (embodiment 16), 470 nm (embodiment 17), 465 nm (embodiment 18), 463 nm (embodiment 19), and 460 nm (embodiment 20), and the half-height width of the emission spectrum was 77 nm (embodiment 16), 80 nm (embodiment 17), 78 nm (embodiment 18), 76 nm (embodiment 19), and 77 nm (embodiment 20). The quantum efficiency of embodiments 16-20 was tested using a quantum efficiency tester, and the values were 85.5% (embodiment 16), 89.1% (embodiment 17), 93.2% (embodiment 18), 92.3% (embodiment 19), and 90.3% (embodiment 20), as shown in Table 1. The quantum efficiency value is extremely high, indicating that the material has extremely high packaging practical value. The structure of the material obtained in embodiments 16-20 was analyzed by X-ray diffraction using an X-ray diffractometer, and the results were basically the same as those of embodiment 1. Figure 9 A graph showing the change in luminescent performance of the material obtained in embodiments 16-20 is given.

[0111] As can be seen, the material obtained in embodiments 16-20 is a high-efficiency narrow-band blue fluorescent material, which emits a spectrum main peak at 455-475 nm and a half-height width in the range of 70-80 nm under 400 nm violet light excitation, with a quantum efficiency > 70%, so that the fluorescent material can be applied to white light LED devices.

[0112] Embodiments 21-25

[0113] The raw materials are BaCO3, Eu2O3, HfO2, SiO2and Al2O3, and the molar ratio of Ba, Eu, Hf, Si and Al in BaCO3, Eu2O3, HfO2, SiO2and Al2O3is 1.96:0.04:2.1:4.6:2.4 (Example 21), 1.96:0.04:2.2:4.2:2.8 (Example 22), 1.96:0.04:2.3:3.8:3.2 (Example 23), 1.96:0.04:2.4:3.4:3.6 (Example 24), 1.96:0.04:2.5:3:4 (Example 25). The above raw materials are ground and mixed uniformly, and then are respectively loaded into a crucible. Under a mixed gas atmosphere of nitrogen and hydrogen at a ratio of 9:1, the crucible is sintered at 1500°C for 6h in a high-temperature furnace, and is cooled to room temperature in the furnace. The material with the following theoretical chemical composition is obtained:

[0114] Ba 1.96 Eu 0.04 Hf 2.1 Si 4.6 Al 2.4 O 19 (Example 21)

[0115] Ba 1.96 Eu 0.04 Hf 2.2 Si 4.2 Al 2.8 O 19 (Example 22)

[0116] Ba 1.96 Eu 0.04 Hf 2.3 Si 3.8 Al 3.2 O 19 (Example 23)

[0117] Ba 1.96 Eu 0.04 Hf 2.4 Si 3.4 Al 3.6 O 19 (Example 24)

[0118] Ba 1.96 Eu 0.04 Hf 2.5 Si3Al4O 19 (Example 25)

[0119] Control matrix chemical formula: Ba2Hf2Si5Al2O 19, embodiments 21-25 increased the interstitial defects of Hf, while adjusting the ratio of Si and Al (although Si and Al occupy the same crystallographic position, the ratio of Si and Al is different, which will inevitably affect the optical band gap and luminescent properties of the material). Referring to Comparative Examples 2-4, theoretically, the luminescent properties of the materials obtained in embodiments 21-25 should be poor, but in fact, the opposite is true. The corresponding phosphor in embodiments 21-25 was analyzed using a fluorescence spectrometer. The results showed that the materials corresponding to embodiments 21-25 could absorb ultraviolet-violet light, and under 400 nm violet light excitation, the emission spectrum main peak was located at 472 nm (example 21), 471 nm (example 22), 470 nm (example 23), 469 nm (example 24) and 468 nm (example 25), and the half-height width of the emission spectrum was 78 nm (example 21), 79 nm (example 22), 80 nm (example 23), 78 nm (example 24) and 75 nm (example 25). The quantum efficiency of examples 21-25 was tested using a quantum efficiency tester, and the values were 91.6% (example 21), 91.5% (example 22), 90.8% (example 23), 89.4% (example 24) and 88.5% (example 25), as shown in Table 1. The quantum efficiency value is extremely high, indicating that the material has extremely high packaging practical value. The structure of the material obtained in examples 21-25 was analyzed by X-ray diffraction using an X-ray diffractometer, and the results were basically the same as those of example 1. Figure 10 A graph showing the change in luminescent properties of the material obtained in examples 21-25 is given.

[0120] As can be seen, the material obtained in examples 21-25 is a high-efficiency narrow-band blue fluorescent material, which emits a spectrum with a main peak at 455-475 nm and a half-height width in the range of 70-80 nm under 400 nm violet light excitation, and the quantum efficiency is >70%, so that the fluorescent material can be applied to white light LED devices.

[0121] Examples 26-30

[0122] The raw materials are BaCO3, Eu2O3, HfO2, SiO2and Al2O3, and the molar ratio of Ba, Eu, Hf, Si and Al in BaCO3, Eu2O3, HfO2, SiO2and Al2O3is 1.95:0.05:2.1:4.6:2.4 (Example 26), 1.95:0.05:2.2:4.2:2.8 (Example 27), 1.95:0.05:2.3:3.8:3.2 (Example 28), 1.95:0.05:2.4:3.4:3.6 (Example 29), and 1.95:0.05:2.5:3:4 (Example 30). The above raw materials are ground and uniformly mixed, and then are separately loaded into crucibles. Under a mixed gas atmosphere of nitrogen and hydrogen at a ratio of 9:1, the crucibles are sintered at 1500°C for 6h in a high-temperature furnace, and then are cooled to room temperature in the furnace. Materials having the following theoretical chemical compositions are obtained:

[0123] Ba 1.95 Eu 0.05 Hf 2.1 Si 4.6 Al 2.4 O 19 (Example 26)

[0124] Ba 1.95 Eu 0.05 Hf 2.2 Si 4.2 Al 2.8 O 19 (Example 27)

[0125] Ba 1.95 Eu 0.05 Hf 2.3 Si 3.8 Al 3.2 O 19 (Example 28)

[0126] Ba 1.95 Eu 0.05 Hf 2.4 Si 3.4 Al 3.6 O 19 (Example 29)

[0127] Ba 1.95 Eu 0.05 Hf 2.5 Si3Al4O 19 (Example 30)

[0128] Comparative matrix chemical formula: Ba2Hf2Si5Al2O 19, embodiments 26-30 increased the interstitial defects of Hf, while adjusting the ratio of Si and Al (although Si and Al occupy the same crystallographic position, the ratio of Si and Al is different, which will inevitably affect the optical band gap and luminescent properties of the material). Referring to Comparative Examples 2-4, theoretically, the luminescent properties of the materials obtained in embodiments 26-30 should be poor, but in fact, the opposite is true. The corresponding phosphor in embodiments 26-30 was analyzed using a fluorescence spectrometer. The results showed that the materials corresponding to embodiments 26-30 could absorb ultraviolet-violet light, and under 400 nm violet light excitation, the emission spectrum main peak was located at 475 nm (example 26), 473 nm (example 27), 475 nm (example 28), 474 nm (example 29) and 469 nm (example 30), and the half-height width of the emission spectrum was 80 nm (example 26), 78 nm (example 27), 80 nm (example 28), 77 nm (example 29) and 76 nm (example 30). The quantum efficiency of examples 26-30 was tested using a quantum efficiency tester, and the values were 87.4% (example 26), 85.6% (example 27), 86.3% (example 28), 82.9% (example 29) and 82.7% (example 30), as shown in Table 1. The quantum efficiency value is extremely high, indicating that the material has extremely high packaging practical value. The structure of the material obtained in examples 26-30 was analyzed by X-ray diffraction using an X-ray diffractometer, and the results were basically the same as those of example 1. Figure 11 A graph showing the change in luminescent properties of the material obtained in examples 26-30 is given.

[0129] As can be seen, the material obtained in examples 26-30 is a high-efficiency narrow-band blue fluorescent material, which emits a spectrum with a main peak at 455-475 nm and a half-height width in the range of 70-80 nm under 400 nm violet light excitation, and a quantum efficiency > 70%, so that the fluorescent material can be applied to white light LED devices.

[0130] Table 1 Luminescent properties of the materials corresponding to the comparative examples and examples

[0131]

[0132]

[0133] Example 31

[0134] The blue fluorescent material of the formula Ba 1.97 Eu 0.03 Hf 2.3 Si 3.8 Al 3.2 O 19 , Lu3Al5O12 :Ce green fluorescent material and Sr 0.9 Ca 0.1 AlSiN3:Eu red fluorescent material, mixed with epoxy resin in a mass ratio of 1:0.77:0.39:5.2, coated on a violet LED with a main peak of emission spectrum at 409 nm, packaged, and then cured at 150°C for 2h to obtain a white LED device with a color rendering index of 90.2. The spectrum of the device is shown in Figure 12

[0135] The above examples are only used to illustrate the embodiments of the present application and explain the technical features of the present application, and are not intended to limit the protection scope of the present application. Any changes or equivalent arrangements that can be easily completed by those skilled in the art shall fall within the scope claimed by the present application, and the protection scope of the present application shall be subject to the claims.​

Claims

1. A high-efficiency narrow-band blue fluorescent material, characterized by: The chemical formula of the high-efficiency narrow-band blue fluorescent material is Ba 2-x Eu x Hf 2+y Si 5-4y Al 2+4y O 19 , where 0<x≤0.05, 0.1≤y≤0.5; under the excitation of 400 nm violet light, the main peak of the emission spectrum is located at 455~475 nm, the half-maximum width is 70~80 nm, and the quantum efficiency is >70%.

2. The high-efficiency narrow-band blue fluorescent material according to claim 1, characterized in that: The x is 0.03 and the y is 0.

3.

3. The method for preparing a high-efficiency narrow-band blue fluorescent material according to any one of claims 1 to 2, characterized in that: A Ba precursor, a Eu precursor, a Hf precursor, a Si precursor and an Al precursor are mixed and subjected to a high-temperature solid-phase reaction under a reducing atmosphere to obtain the high-efficiency narrow-band blue fluorescent material.

4. The method for preparing a high-efficiency narrow-band blue fluorescent material according to claim 3, wherein: The molar ratio of Ba, Eu, Hf, Si and Al in the Ba precursor, Eu precursor, Hf precursor, Si precursor and Al precursor is (2-x):x:(2+y): (5-4y):(2+4y), wherein 0<x≤0.05, 0.1≤y≤0.

5.

5. The method for preparing a high-efficiency narrow-band blue fluorescent material according to claim 3, wherein: The Ba precursor is selected from one or more of Ba carbonate, Ba oxide, Ba oxalate and Ba nitrate; the Eu precursor is selected from one or more of Eu carbonate, Eu oxide, Eu oxalate and Eu nitrate.

6. The method for preparing a high-efficiency narrow-band blue fluorescent material according to claim 3, wherein: The Hf precursor is selected from HfO2; the Si precursor is selected from SiO2; and the Al precursor is selected from one or more of Al carbonate, Al oxide, Al oxalate and Al nitrate.

7. The method for preparing a high-efficiency narrow-band blue fluorescent material according to claim 3, wherein: The temperature of the high-temperature solid-phase reaction is 1400-1600° C., and the time of the high-temperature solid-phase reaction is 4-10 hours.

8. Use of the high-efficiency narrow-band blue fluorescent material according to any one of claims 1 to 2 or the high-efficiency narrow-band blue fluorescent material prepared by the method according to any one of claims 3 to 7, characterized in that: Used to prepare white light LED devices.

9. A white light LED device, characterized in that: The invention comprises a high-efficiency narrow-band blue fluorescent material according to any one of claims 1 to 2 or a high-efficiency narrow-band blue fluorescent material obtained by the preparation method according to any one of claims 3 to 7.

10. The white light LED device according to claim 9, wherein: It also includes a purple LED chip that can emit a peak wavelength between 380 and 425 nm.

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