Ultraviolet / purple light excited blue fluorescent material as well as preparation method and application thereof

Abstract

The invention relates to an ultraviolet / purple light excited blue fluorescent material as well as a preparation method and application thereof. The Eu < 2 + > doped oxide-based blue fluorescent material has a chemical expression of BaHfSi2O7: xEu < 2 + >, and x is more than or equal to 0.003 and less than or equal to 0.02. Compared with the prior art, the purple-light-excited blue fluorescent material provided by the invention is brand-new and unreported ultraviolet-excited Eu < 2 + >-doped oxide-based 472nm blue-light-emitting fluorescent powder, the fluorescent powder has a wide excitation band, the excitation spectrum range covers 200-450nm, the emission spectrum range covers 390-680nm, and the fluorescent material has a good fluorescent effect under the excitation of 304nm near ultraviolet light. The blue light with the central wavelength of 472nm is emitted, and meanwhile, the blue light emitting material has excellent stability and luminous efficiency. The fluorescent powder can be prepared by adopting a conventional solid-phase reaction method, has the characteristics of simple preparation process and facilitation of industrial production, can be combined with a near ultraviolet chip to generate white light, can be used as a good candidate material for wide application of a white light LED, and can meet the urgent demand of a current healthy illumination LED light source.

Description

Technical Field

[0001] The present invention relates to the technical field of fluorescent material preparation, and in particular to an ultraviolet / violet light excited blue fluorescent material and a preparation method and application thereof. Background Art

[0002] With the rapid development of economy, people's living standard is also improving, and the requirements for lighting quality are getting higher and higher. White light emitting diode (W-LED) has been widely studied and applied due to its advantages such as low power consumption, high stability and excellent luminous efficiency. There are two common methods to obtain this white light. One is to synthesize white light through a multi-chip set of red, green and blue primary colors and light emission. However, due to the different light decay of the three primary color chips, the color temperature is unstable, the control circuit is more complicated and the cost is higher. Another method is to combine InGaN blue light chip with yellow phosphor Y 3 Al 5 O 12 :Ce 3+ (YAG:Ce 3+ ), this method has a strong blue light chip peak, and the blue light part is too strong, resulting in uneven luminous intensity, low color rendering index, high color temperature, and certain blue light hazards that are not conducive to physical and mental health. Therefore, we are looking for three-color (blue, green, and red) phosphors that are effectively excited in the near-ultraviolet region and combined with near-ultraviolet chips to produce white light. This method can effectively avoid low color rendering index, high color temperature and blue light hazards, and is a method with application prospects. Blue phosphor is one of the most important components of three-color phosphors, so the synthesis of blue phosphors with strong absorption in the near-ultraviolet region plays an important role in healthy lighting.

[0003] For example, Xinguo Zhang et al. prepared a KBaYSi 2 O 7 :Ce 3+ The blue phosphor emits blue emission centered at 440nm under 365nm near-ultraviolet excitation, but its internal quantum efficiency is only 35%, and the emission intensity at 100°C only remains at about 75% of the initial intensity at room temperature. The luminous efficiency and stability need to be improved. Summary of the invention

[0004] The purpose of the present invention is to provide a blue fluorescent material excited by ultraviolet / violet light and its preparation method and application, which is a new type of ultraviolet / violet light excited Eu 2+ Doped oxide-based 472nm blue light emitting phosphor with excellent luminous efficiency and stability, can be combined with near-ultraviolet chips to produce white light.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] One of the purposes of the present invention is to provide a blue fluorescent material excited by ultraviolet / violet light, which is Eu 2+ Doped oxide-based blue fluorescent material, the chemical formula is BaHfSi 2 O 7 :xEu 2+ , where 0.003≤x≤0.02.

[0007] Preferably, x=0.003, 0.005, 0.01, 0.0015 or 0.02.

[0008] Preferably, the excitation spectrum range of the blue fluorescent material excited by ultraviolet / violet light covers 200-450nm, the emission spectrum range of the blue fluorescent material excited by ultraviolet / violet light covers 390-680nm, and the fluorescent material emits blue light with a central wavelength of 472nm under excitation by 304nm near-ultraviolet light.

[0009] Further preferably, the excitation spectrum range of the blue fluorescent material excited by ultraviolet / violet light covers 200-420 nm.

[0010] Preferably, the effective absorption range of the ultraviolet / violet light excited blue fluorescent material covers 200-450nm, and it can be excited by ultraviolet / violet light, and the emission center emits blue light with a wavelength of 472nm.

[0011] Preferably, the blue fluorescent material excited by ultraviolet / violet light is a powdery material.

[0012] The second object of the present invention is to provide a method for preparing the ultraviolet / violet light excited blue fluorescent material, comprising the following steps:

[0013] S1. According to the stoichiometric ratio, weigh the raw material powders of the barium source compound, the hafnium source compound, the europium source compound and the silicon source compound, and mix them evenly to obtain a mixture;

[0014] S2, grinding and mixing the mixture to obtain raw material powder;

[0015] S3, sintering the raw material powder, and then cooling it to room temperature to finally obtain the ultraviolet / violet light excited blue fluorescent material.

[0016] Preferably, in step S1, the silicon source compound is SiO 2 , the barium source compound is BaCO 3 , the hafnium source compound is HfO 2 , the europium source compound is Eu 2 O 3 .

[0017] Preferably, in step S2, the grinding time is 10 to 60 minutes.

[0018] Preferably, in step S3, the sintering conditions are: carried out in a reducing atmosphere, the sintering temperature is 1000-1500° C., and the sintering time is 2-12 hours.

[0019] Further preferably, in step S3, the sintering conditions are: carried out in a reducing atmosphere, the sintering temperature is 1000-1400° C., and the sintering time is 2-12 hours.

[0020] More preferably, in step S3, the sintering temperature is 1300-1400°C.

[0021] More preferably, in step S3, the sintering time is 6 hours.

[0022] Further preferably, in step S3, the reducing atmosphere is selected from H 2 With a volume fraction of 95% N 2 of mixed gases.

[0023] Further preferably, in step S3, during the sintering process, the system pressure is maintained at 0 MPa.

[0024] Further preferably, in step S3, the sintering specifically refers to: loading the raw material powder into an alumina crucible, and then placing the alumina crucible containing the raw material powder in a reducing atmosphere for sintering.

[0025] The third object of the present invention is to provide an application of the blue fluorescent material excited by ultraviolet / violet light, wherein the blue fluorescent material excited by ultraviolet / violet light is used to prepare LED chips.

[0026] Preferably, the LED chip can be applied to white light LED, sunlight-like LED, full-spectrum LED, healthy lighting LED light source, etc.

[0027] In the phosphor system, silicate phosphor is considered to be a high-brightness phosphor because of its excellent optical properties and physical and chemical stability. At the same time, silicate has good chemical stability and thermal stability, and its raw materials have a fluxing effect, which reduces the synthesis temperature of the material and can effectively reduce the production cost of the material. Therefore, it is a very potential phosphor material.

[0028] The present invention uses Eu 2+ As the luminescent center of the phosphor, a fluorescent material with strong blue light emission is synthesized. 2+ It is a rare earth ion with excellent luminescence properties. 6 5d 1The outer electron configuration, its 5d orbital is exposed in the outer layer, under the action of the local vibration of the matrix crystal structure, 4f 6 5d 1 The split energy levels will become continuous energy bands. 2+ Luminescence properties of ions and their 4f 6 5d 1 The energy levels are closely related and strongly depend on the local environment. Therefore, by adjusting the crystal field splitting and the local position symmetry, the molecule in the excited singlet state returns to the lowest vibrational energy level of the first excited singlet state through internal conversion and vibrational relaxation, and then returns to any vibrational energy level of the ground state by emitting a light quantum in the form of radiation.

[0029] The ultraviolet / violet light excited blue fluorescent material provided by the present invention is a brand new and unreported ultraviolet / ultraviolet excited Eu 2+ The doped oxide-based 472nm blue light emitting fluorescent material has a wide excitation band, an effective absorption range covering 200-450nm, can be excited by ultraviolet / violet light, and the emission center emits blue light with a wavelength of 472nm. It has the advantages of stable physical and chemical properties and high luminous efficiency (internal quantum efficiency), which is comparable to the existing KBaYSi 2 O 7 :Ce 3+ The blue phosphor of the present invention has a high luminous efficiency of 83.67%, which is much higher than that of KBaYSi 2 O 7 :Ce 3+ The emission intensity of blue phosphor (35%) at 150°C still remains about 80% of the initial intensity at room temperature, which is higher than that of blue phosphor KBaYSi 2 O 7 :Ce 3+ (100℃-75%).

[0030] At the same time, the phosphor of the present invention can be prepared by a conventional solid phase reaction method, has the characteristics of simple preparation process and is conducive to industrial production, and can be used as a good candidate material for the wide application of white light LEDs. The phosphor can be well matched with existing ultraviolet chips, meet the needs of the commercial market, and is suitable for the application of white light LEDs, sunlight-like LEDs, full-spectrum LEDs, etc.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] (1) The present invention provides a UV-excited Eu 2+The doped oxide-based 472nm blue light-emitting fluorescent material has high luminous efficiency and stability, and can meet the urgent needs of current white light LEDs, sunlight-like LEDs, full-spectrum LEDs, and healthy lighting LED light sources.

[0033] (2) The luminous efficiency (internal quantum efficiency) of the blue phosphor of the present invention is high, up to 83.67%, and the chemical properties are stable. The emission intensity at 150°C still maintains about 80% of the initial intensity at room temperature, which is higher than that of the commercial blue phosphor KBaYSi 2 O 7 :Ce 3+ .

[0034] (3) The fluorescent material of the present invention has a wide excitation band, and the effective absorption range covers 200-450nm. It can be excited by ultraviolet light. The obtained fluorescent powder can emit blue light with a central wavelength of 472nm under the excitation of 304nm near-ultraviolet light.

[0035] (4) The fluorescent material of the present invention has an emission wavelength of 390-680nm and can effectively absorb light in the wavelength range of 200-450nm. It can be well matched with existing ultraviolet chips to meet the needs of the commercial market.

[0036] (5) The fluorescent material of the present invention can be excited under near-ultraviolet light and can be combined with a near-ultraviolet chip to produce white light, which can effectively avoid the hazards of low color rendering index, high color temperature and blue light, and is suitable for the application of healthy lighting LED light sources.

[0037] (6) The fluorescent material of the present invention has the advantage of stable physical and chemical properties. At the same time, the fluorescent material can be prepared by a conventional solid-phase reaction method, has the characteristics of simple preparation process and is conducive to industrial production. It can be used as a good candidate material for the widespread application of white light LEDs and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a photoexcitation spectrum diagram of the ultraviolet / violet light excited blue phosphor prepared in Examples 1-5 of the present invention.

[0039] Figure 2 It is a photoemission spectrum of the ultraviolet / violet light excited blue phosphor prepared in Examples 1-5 of the present invention.

[0040] Figure 3 This is a thermal stability curve of the ultraviolet / violet light excited blue phosphor prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0041] This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and a specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0042] Unless otherwise specified, the reagents, methods, instruments and equipment used in the present invention are conventional reagents, methods, instruments and equipment in the art. Unless otherwise specified, the reagents and materials used in the following examples are commercially available.

[0043] A blue fluorescent material excited by ultraviolet / violet light, which is Eu 2+ Doped oxide-based blue fluorescent material, the chemical formula is BaHfSi 2 O 7 :xEu 2+ , wherein 0.003≤x≤0.02. The excitation spectrum range of the blue fluorescent material excited by ultraviolet / violet light covers 200-450nm, the emission spectrum range of the blue fluorescent material excited by ultraviolet / violet light covers 390-680nm, and the fluorescent material emits blue light with a central wavelength of 472nm under the excitation of 304nm near-ultraviolet light.

[0044] The preparation method is as follows:

[0045] S1. According to the stoichiometric ratio, weigh the raw material powders of the barium source compound, the hafnium source compound, the europium source compound and the silicon source compound, and mix them evenly to obtain a mixture;

[0046] S2, grinding and mixing the mixture to obtain raw material powder;

[0047] S3, sintering the raw material powder, and then cooling it to room temperature to finally obtain the ultraviolet / violet light excited blue fluorescent material.

[0048] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0049] Embodiment 1:

[0050] This embodiment provides a blue fluorescent material excited by ultraviolet / violet light, and the steps of the preparation method thereof are as follows:

[0051] 1. Weigh BaCO according to the stoichiometric ratio 3 、SiO 2 、Eu 2 O 3 , HfO 2 Raw material powder 1g.

[0052] 2. Grind the raw material mixture in an agate mortar for 30 to 60 minutes. After the materials are evenly mixed, load the mixture into an alumina crucible and place it in H 2 and N2 The product was calcined at 1350 °C for 6 h in a reducing atmosphere and then cooled to room temperature to obtain the target product.

[0053] The ultraviolet / violet light excited Eu obtained in this embodiment 2+ The general formula of the doped blue light emitting phosphor is BaHfSi 2 O 7 :xEu 2+ , x is 0.003.

[0054] Embodiment 2:

[0055] This embodiment provides a blue fluorescent material excited by ultraviolet / violet light, and the steps of its preparation method are: 1.

[0056] Weigh BaCO according to the stoichiometric ratio 3 、SiO 2 、Eu 2 O 3 , HfO 2 Raw material powder 1g.

[0057] 2. Grind the raw material mixture in an agate mortar for 30 to 60 minutes. After the materials are evenly mixed, load the mixture into an alumina crucible and place it in H 2 and N 2 The luminescent material was calcined at 1350° C. for 6 h in a reducing atmosphere and then cooled to room temperature to obtain the target product. The photoluminescence performance of the luminescent material is similar to that in Example 1.

[0058] The general formula of the ultraviolet / violet light excited Eu doped blue light emitting phosphor obtained in this embodiment is BaHfSi 2 O 7 :xEu 2+ , x is 0.005.

[0059] Embodiment 3:

[0060] This embodiment provides a blue fluorescent material excited by ultraviolet / violet light, and the steps of the preparation method thereof are as follows:

[0061] 1. Weigh BaCO according to the stoichiometric ratio 3 、SiO 2 、Eu 2 O 3 , HfO 2 Raw material powder 1g.

[0062] 2. Grind the raw material mixture in an agate mortar for 30 to 60 minutes. After the materials are evenly mixed, load the mixture into an alumina crucible and place it in H 2 and N 2The luminescent material was calcined at 1350° C. for 6 h in a reducing atmosphere and then cooled to room temperature to obtain the target product. The photoluminescence performance of the luminescent material is similar to that in Example 1.

[0063] The general formula of the ultraviolet / violet light excited Eu doped blue light emitting phosphor obtained in this embodiment is BaHfSi 2 O 7 :xEu 2 + , x is 0.01.

[0064] Embodiment 4:

[0065] This embodiment provides a blue fluorescent material excited by ultraviolet / violet light, and the steps of the preparation method thereof are as follows:

[0066] 1. Weigh BaCO according to the stoichiometric ratio 3 、SiO 2 、Eu 2 O 3 , HfO 2 Raw material powder 1g.

[0067] 2. Grind the raw material mixture in an agate mortar for 30 to 60 minutes. After the materials are evenly mixed, load the mixture into an alumina crucible and place it in H 2 and N 2 The luminescent material was calcined at 1350° C. for 6 h in a reducing atmosphere and then cooled to room temperature to obtain the target product. The photoluminescence performance of the luminescent material is similar to that in Example 1.

[0068] The general formula of the ultraviolet / violet light excited Eu doped blue light emitting phosphor obtained in this embodiment is BaHfSi 2 O 7 :xEu 2 + , x is 0.015.

[0069] Embodiment 5:

[0070] This embodiment provides a blue fluorescent material excited by ultraviolet / violet light, and the steps of the preparation method thereof are as follows:

[0071] 1. Weigh BaCO according to the stoichiometric ratio 3 、SiO 2 、Eu 2 O 3 , HfO 2 Raw material powder 1g.

[0072] 2. The raw material mixture was ground in an agate mortar for 30 to 60 minutes. After the materials were evenly mixed, the mixture was loaded into an alumina crucible and calcined at 1350° C. for 6 hours in a reducing atmosphere of hydrogen and nitrogen mixture, and then cooled to room temperature to obtain the target product. The photoluminescence performance of the luminescent material was similar to that in Example 1.

[0073] The general formula of the ultraviolet / violet light excited Eu doped blue light emitting phosphor obtained in this embodiment is BaHfSi 2 O 7 :xEu 2 + , x is 0.02.

[0074] The present invention uses Hitachi Analytical Instruments F-7000 fluorescence spectrophotometer to test the fluorescence performance of the target sample, and the results are shown in Table 1.

[0075] Table 1 Preparation parameters and performance test results of Examples 1-5

[0076]

[0077] The internal quantum efficiency (luminous efficiency) of Example 1 was calculated and tested. The calculation method of the internal quantum efficiency is as follows: Φ = Φ d -(1-A d )Φ i

[0078] Among them, Φ d : Quantum yield when directly excited

[0079] A d : Absorption rate during direct excitation

[0080] Φ i : Quantum yield for indirect excitation

[0081] According to calculation, the luminous efficiency of the blue phosphor in Example 1 is relatively high, reaching 83.67%.

[0082] The stability test of Example 1 was carried out, and the results were as follows Figure 3 As shown, the blue phosphor prepared in Example 1 has stable chemical properties, and its emission intensity at 150° C. still maintains about 80% of the initial intensity at room temperature.

[0083] In summary, the present invention produces a new, unreported ultraviolet / violet light excited Eu 2+The doped oxide-based 472nm blue light emitting fluorescent material has excellent luminous efficiency and stability. The fluorescent material is a powdered material with an effective absorption range of 200-450nm, which can be excited by ultraviolet / violet light. The obtained phosphor can emit blue light with a central wavelength of 472nm under the excitation of 304nm near-ultraviolet light. It can be combined with near-ultraviolet chips to produce white light, which can meet the urgent needs of white light LEDs, sunlight-like LEDs, full-spectrum LEDs, and healthy lighting LED light sources.

[0084] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A blue fluorescent material excited by ultraviolet / violet light, characterized in that: It is Eu 2+ Doped oxide-based blue fluorescent material, the chemical formula is BaHfSi2O7:xEu 2+ , where 0.003≤x≤0.

02.

2. The ultraviolet / violet light excited blue fluorescent material according to claim 1, characterized in that: x=0.003, 0.005, 0.01, 0.0015 or 0.

02.

3. The ultraviolet / violet light excited blue fluorescent material according to claim 1, characterized in that: The excitation spectrum range of the blue fluorescent material excited by ultraviolet / violet light covers 200-450nm, the emission spectrum range of the blue fluorescent material excited by ultraviolet / violet light covers 390-680nm, and the fluorescent material emits blue light with a central wavelength of 472nm under the excitation of 304nm near-ultraviolet light.

4. The ultraviolet / violet light excited blue fluorescent material according to claim 1, characterized in that: The blue fluorescent material excited by ultraviolet / violet light is a powdery material.

5. A method for preparing a blue fluorescent material excited by ultraviolet / violet light as claimed in any one of claims 1 to 4, characterized in that: The following steps are involved: S1. According to the stoichiometric ratio, weigh the raw material powders of the barium source compound, the hafnium source compound, the europium source compound and the silicon source compound, and mix them evenly to obtain a mixture; S2, grinding and mixing the mixture to obtain raw material powder; S3, sintering the raw material powder, and then cooling it to room temperature to finally obtain the ultraviolet / violet light excited blue fluorescent material.

6. The method for preparing a blue fluorescent material excited by ultraviolet / violet light according to claim 5, characterized in that: In step S1, the silicon source compound is SiO2, the barium source compound is BaCO3, the hafnium source compound is HfO2, and the europium source compound is Eu2O3.

7. The method for preparing a blue fluorescent material excited by ultraviolet / violet light according to claim 5, characterized in that: In step S2, the grinding time is 10 to 60 minutes.

8. The method for preparing a blue fluorescent material excited by ultraviolet / violet light according to claim 5, characterized in that: In step S3, the sintering conditions are: carried out in a reducing atmosphere, the sintering temperature is 1000-1400° C., and the sintering time is 2-12 hours.

9. The method for preparing a blue fluorescent material excited by ultraviolet / violet light according to claim 8, characterized in that: In step S3, the reducing atmosphere is selected from a mixed gas of 5% by volume H2 and 95% by volume N2.

10. An application of the ultraviolet / violet light excited blue fluorescent material as claimed in any one of claims 1 to 4, characterized in that: The blue fluorescent material excited by ultraviolet / violet light is used to prepare LED chips.

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