High-thermal-stability deep red fluorescent material, preparation method and LED light source

Abstract

The present application relates to a kind of high thermal stability deep red fluorescent material, preparation method and LED light source.The fluorescent material is La2O3-MgO-A2O5-Sm2O3 system, wherein A is selected from one or more combinations of Nb, Ta or Sb;The molar ratio of La:Mg:A:Sm in the La2O3-MgO-A2O5-Sm2O3 system is (1.9-1.99):1:1:(0.01-0.1).Preparation method is: proportionally weigh La source compound, Mg source compound, A source compound and samarium source compound, grind and mix each raw material, then primary sintering is carried out, to obtain precursor;The precursor is secondly ground and mixed, then secondary sintering is carried out, to obtain the deep red fluorescent material.Compared with prior art, the deep red fluorescent material of the present application can effectively absorb 400-410nm wavelength violet light, and emit strong red light with center wavelength at 650nm, which can be well matched with violet chip to package and prepare LED light emitting device.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of fluorescent materials, and particularly relates to a deep red fluorescent material with high thermal stability, a preparation method and an LED light source. BACKGROUND

[0002] With the development of the LED industry, people's demand for white light has changed to full-spectrum healthy white light similar to sunlight. However, the current mainstream white light scheme of combining a blue light chip with multi-color fluorescent powder lacks a purple light component, cannot well simulate sunlight, and the chip will overflow excessive blue light, which is harmful to humans. The white light scheme of combining a purple light (400-420 nm) InGaN chip with multi-color fluorescent powder can more easily produce full-spectrum white light similar to the sunlight spectrum, while avoiding the blue light hazard, and can provide a healthier WLED. Therefore, multi-color fluorescent powder excited by a purple light LED chip has gradually become a research hotspot.

[0003] Compared with blue light-excited fluorescent powder, purple light-excited fluorescent powder is relatively scarce, and there are few reports on long-wavelength emission (orange red, red) fluorescent powder that can be excited by purple light, most of which are nitrides or fluorides. It is well known that nitride fluorescent powder is usually prepared under harsh conditions such as high temperature and high pressure, and is expensive; and fluoride fluorescent powder has poor chemical stability and general thermal stability. Therefore, there is still an urgent need for oxide-based long-wavelength emission fluorescent powder excited by purple light with high thermal stability.

[0004] In addition, the thermal quenching (TQ) characteristic is a common characteristic of fluorescent powder, and this negative characteristic can directly affect the quality of the light source (because the chip will generate a large amount of heat when working, about 150℃). Therefore, researchers have been committed to developing fluorescent powder with better thermal stability to reduce the negative effects of heat on the continuous lighting of LEDs. CN116751590A discloses a fluorescent material capable of stably and efficiently emitting far red light, which is prepared by doping Bi 3+ and rare earth ions in a scandate matrix and replacing Sc 3 + Mn 4+ , solves the problems of low luminous efficiency and poor thermal stability of existing Mn 4+ doped red light fluorescent powder, and realizes efficient emission of far red light under near-ultraviolet light. However, the far red light fluorescent material still cannot be matched with a purple light LED chip, and is not suitable for preparing a white light LED device excited by purple light.

[0005] Therefore, a new oxide-based deep red fluorescent powder with strong absorption in the purple light region and high thermal stability still needs to be developed to meet the market demand for white light LED light source devices excited by purple light. SUMMARY

[0006] The present application aims to provide a deep red fluorescent material with high thermal stability, a preparation method and a LED light source, to develop a new oxide-based deep red fluorescent powder with strong absorption and high thermal stability in the violet region, to meet the market demand for white light LED light source devices excited by violet light.

[0007] The object of the present application can be achieved by the following technical solutions:

[0008] The present application provides a deep red fluorescent material with high thermal stability, which is a La2O3-MgO-A2O5-Sm2O3 system, wherein A is selected from Nb, Ta or Sb.

[0009] The molar ratio of La:Mg:A:Sm in the La2O3-MgO-A2O5-Sm2O3 system is (1.9-1.99):1:1:(0.01-0.1).

[0010] Further, the molar ratio of La:Mg:A:Sm in the La2O3-MgO-A2O5-Sm2O3 system is (1.9-1.99):1:1:(0.01-0.1). When Sm is not doped, the system will not emit light; when the doping of Sm is excessive, it will cause concentration quenching, and the luminescence intensity will decrease instead.

[0011] Further, the molar ratio of La:Mg:A:Sm in the La2O3-MgO-A2O5-Sm2O3 system is 1.99:1:1:0.01 or 1.98:1:1:0.02 or 1.97:1:1:0.03.

[0012] Further, the components in the La2O3-MgO-A2O5-Sm2O3 system are as follows in terms of mass percentage of oxides: 52.62%≤La2O3≤64.95%, 6.85%≤MgO≤8.07%, 26.57%≤A2O5≤37.63%, 0.30%≤Sm2O3≤3.49%.

[0013] Further, the excitation spectral range of the fluorescent material is 365-385nm, 400-410nm and 475-500nm.

[0014] Further, the optimal excitation spectral range of the fluorescent material is 400-410nm, preferably 405-410nm, and the optimal excitation is located at 407nm, which can be adapted to the 410nm violet excitation chip commercially available.

[0015] Further, the emission center wavelength of the fluorescent material is 650nm, accompanied by multi-peak narrow-band emission of 550-625nm and 675-750nm.

[0016] Further, the color coordinates of the fluorescent material are (0.627, 0.369).

[0017] The fluorescent powder of the present application is Sm 3+ The doped oxide-based red light emitting fluorescent material, in the La2O3-MgO-A2O5-Sm2O3 system of the present application, has the advantages of good stability and easy preparation of the oxide matrix composed of La2O3, MgO and A2O5, and Sm 3+ The doping of ions can obtain the luminescent performance with the optimal excitation value located in the violet light region.

[0018] The present application also provides a preparation method of the high-thermal-stability deep red light fluorescent material, specifically comprising the following steps:

[0019] S1: proportionally weighing La source compounds, Mg source compounds, A source compounds and samarium source compounds, grinding and mixing the raw materials to obtain a mixture;

[0020] S2: primary sintering the mixture obtained in S1 to obtain a precursor;

[0021] S3: secondary grinding and mixing the precursor obtained in S2 and then secondary sintering to obtain the deep red light fluorescent material.

[0022] Further, in step S1, the La source compounds, Mg source compounds, A source compounds and samarium source compounds are each independently selected from one or more of the corresponding metal elements in the form of simple substance, oxide, chloride, sulfide, carbonate, sulfate, phosphate and nitrate.

[0023] Further, in step S1, the grinding time is 5-120 min, preferably 20-50 min.

[0024] Further, in step S2, the primary sintering is performed in an air atmosphere.

[0025] Further, in step S2, the temperature of the primary sintering is 200-800℃, preferably 300-650℃.

[0026] Further, in step S2, the time of the primary sintering is 5-24 h, preferably 5-12 h.

[0027] Further, in step S3, the time of the secondary grinding is 5-120 min, preferably 20-50 min.

[0028] Further, in step S3, the secondary sintering is performed in an inert atmosphere.

[0029] Further, the inert atmosphere is selected from one or more of nitrogen, helium, and argon.

[0030] Further, in step S3, the temperature of the secondary sintering is 1000-1700℃, preferably 1200-1550℃.

[0031] Further, in step S3, the time of the secondary sintering is 1-24h, preferably 4-18h.

[0032] Further, the system pressure during the primary sintering and the secondary sintering is maintained at 1 atmosphere.

[0033] The application also provides a use of the deep red fluorescent material with high thermal stability in the preparation of an LED light source.

[0034] Further, the LED light source includes a violet excitation white light LED light source, a violet excitation sunlight-like LED light source, a violet excitation full-spectrum LED light source, or a violet excitation high-quality white light LED light source.

[0035] The application also provides one of the LED light sources, which is prepared by encapsulating the deep red fluorescent material, blue fluorescent powder, green fluorescent powder, and a violet chip.

[0036] Further, the LED light source has a color rendering index no less than 90, and has a relatively high color rendering index.

[0037] Compared with the prior art, the application has the following beneficial effects:

[0038] (1) The deep red fluorescent material of the application can be excited by near-ultraviolet, violet, and blue light, can effectively absorb violet light with a wavelength of 400-410nm, and can emit strong red light with a center wavelength of 650nm, and has good luminescent performance and thermal stability, and can be well matched with a violet chip to prepare an LED light-emitting device.

[0039] (2) The deep red fluorescent powder of the application has an optimal excitation wavelength in the violet region, and can be well matched with an existing violet chip, has excellent luminescent performance, meets the commercial market demand, and has great development potential in the health lighting field such as a violet excitation white light LED, a violet excitation sunlight-like LED, and a violet excitation full-spectrum LED.

[0040] (3) The deep red fluorescent powder of the application is Sm 3+ The doped oxide-based red light emitting fluorescent material has the advantages of stable physical and chemical properties, and the fluorescent powder of the application can be prepared by a solid phase reaction method, and has the characteristics of simple preparation process, low cost, and being conducive to industrial production.

[0041] (4) The deep red light fluorescent powder of the present application has excellent anti-thermal quenching performance, and can maintain a luminous intensity of more than 90% at 150°C, so as to ensure excellent light emitting performance of the LED chip during operation, thereby reducing the negative impact of heat effect on the continuous lighting of the LED.

[0042] (5) The deep red light fluorescent powder of the present application can be packaged together with commercial blue light fluorescent powder and green light fluorescent powder to prepare an LED device, and exhibits a higher color rendering index and a lower color temperature. BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1 The figure is the photoluminescence excitation-emission spectrum of the deep red light fluorescent material in Example 1-3 of the present application.

[0044] Figure 2 The figure is the XRD spectrum of the deep red light fluorescent material in Example 1-3 of the present application.

[0045] Figure 3 The figure is the thermal stability test result of the deep red light fluorescent material in Example 1 of the present application.

[0046] Figure 4 The figure is the electroluminescence spectrum of the LED device prepared by packaging the red light fluorescent powder of Example 1 together with commercial blue powder and green powder. DETAILED DESCRIPTION

[0047] The present application will be described in detail below in combination with the drawings and specific examples. The present embodiment is implemented on the premise of the technical solution of the present application, and gives detailed implementation mode and specific operation process, but the protection scope of the present application is not limited to the following examples.

[0048] The equipment used in the following examples is conventional equipment in the art unless otherwise specified; the reagents used are commercially available products or prepared by conventional methods in the art unless otherwise specified; and the following examples are implemented by conventional experimental means in the art.

[0049] Example 1:

[0050] The present embodiment provides a deep red light fluorescent material with purple light excitation and high thermal stability, which is applied to the preparation of an LED light source, and the specific steps are as follows:

[0051] (1) Select lanthanum oxide (La2O3), magnesium oxide (MgO), niobium pentoxide (Nb2O5), and samarium oxide (Sm2O3) as starting materials, and La:Mg:Nb:Sm = 1.99:1:1:0.01 (molar ratio). Four kinds of raw material powders are weighed according to the measured ratio, the total mass of the raw material powders is controlled to be 10g, and each raw material powder is placed in an agate mortar and ground for 20min to mix uniformly, to obtain a mixture.

[0052] (2) The mixture is placed in an alumina crucible, the alumina crucible containing the mixture is placed in a muffle furnace, and calcination is carried out at 300°C for 5h in an air atmosphere, the pressure is kept at 1atm, and natural cooling is carried out to room temperature to obtain a precursor.

[0053] (3) The precursor is again placed in an agate mortar and ground for 20min to mix uniformly, the precursor is placed in an alumina crucible, the alumina crucible containing the precursor is placed in a vacuum tube furnace, vacuum is extracted, and sintering is carried out at 1200°C for 4h in a nitrogen inert atmosphere, the pressure is kept at 1atm, and natural cooling is carried out to room temperature to obtain a powder-like deep red light fluorescent material with purple light excitation and high thermal stability.

[0054] Example 2:

[0055] The embodiment provides a deep red light fluorescent material with purple light excitation and high thermal stability, and a preparation method thereof is basically the same as that in example 1. The difference lies in that in step S1, La:Mg:Nb:Sm = 1.98:1:1:0.02 (molar ratio), in step S2, calcination is carried out at 350°C for 6h in an air atmosphere, and in step S3, sintering is carried out at 1250°C for 6h in a nitrogen (N2) inert atmosphere. The specific steps are as follows:

[0056] (1) Select lanthanum oxide, magnesium oxide, niobium pentoxide, and samarium oxide as starting materials, and La:Mg:Nb:Sm = 1.98:1:1:0.02 (molar ratio), four kinds of raw material powders are weighed according to the measured ratio, the total mass of the raw material powders is controlled to be 10g, and each raw material powder is placed in an agate mortar and ground for 20min to mix uniformly, to obtain a mixture.

[0057] (2) The mixture is placed in an alumina crucible, the alumina crucible containing the mixture is placed in a muffle furnace, and calcination is carried out at 350°C for 6h in an air atmosphere, and natural cooling is carried out to room temperature to obtain a precursor.

[0058] (3) The precursor is placed in a agate mortar again and ground for 20 min to mix evenly. The precursor is placed in an alumina crucible. The alumina crucible containing the precursor is placed in a vacuum tube furnace. Vacuum is drawn. The precursor is sintered at 1250°C for 6 h in a nitrogen inert atmosphere. The pressure is kept at 1 atm. The precursor is naturally cooled to room temperature. A powdery deep red light fluorescent material excited by purple light and high-thermal stability is obtained.

[0059] Example 3

[0060] The embodiment provides a deep red light fluorescent material excited by purple light and high-thermal stability. The preparation method is basically the same as that in Example 1. The difference lies in that in step S1, La:Mg:Nb:Sm = 1.97:1:1:0.03 (molar ratio), in step S2, the precursor is calcined at 400°C for 7 h in an air atmosphere, and in step S3, the precursor is sintered at 1300°C for 8 h in a nitrogen (N2) inert atmosphere. The specific steps are as follows:

[0061] (1) Lanthanum oxide, magnesium oxide, niobium pentoxide and samarium oxide are selected as starting materials. La:Mg:Nb:Sm = 1.97:1:1:0.03 (molar ratio). The four kinds of raw material powders are weighed according to the metering ratio. The total mass of the raw material powders is controlled to be 10 g. The raw material powders are placed in an agate mortar and ground for 20 min to mix evenly. A mixture is obtained.

[0062] (2) The mixture is placed in an alumina crucible. The alumina crucible containing the mixture is placed in a muffle furnace. The precursor is calcined at 400°C for 7 h in an air atmosphere. The precursor is naturally cooled to room temperature. A precursor is obtained.

[0063] (3) The precursor is placed in a agate mortar again and ground for 20 min to mix evenly. The precursor is placed in an alumina crucible. The alumina crucible containing the precursor is placed in a vacuum tube furnace. Vacuum is drawn. The precursor is sintered at 1250°C for 6 h in a nitrogen inert atmosphere. The pressure is kept at 1 atm. The precursor is naturally cooled to room temperature. A powdery deep red light fluorescent material excited by purple light and high-thermal stability is obtained.

[0064] Example 4

[0065] The embodiment provides a deep red light fluorescent material excited by purple light and high-thermal stability. The preparation method is basically the same as that in Example 1. The difference lies in that in step S1, La:Mg:Ta:Sm = 1.99:1:1:0.01 (molar ratio), in step S2, the precursor is calcined at 450°C for 8 h in an air atmosphere, and in step S3, the precursor is sintered at 1350°C for 10 h in a helium (He) inert atmosphere. The specific steps are as follows:

[0066] (1) Select lanthanum oxide, magnesium oxide, tantalum pentoxide, samarium oxide as starting materials, La:Mg:Ta:Sm = 1.99:1:1:0.01 (molar ratio), respectively according to the measured ratio of four kinds of raw material powder, control the total mass of raw material powder is 10g, each raw material powder is placed in the agate mortar and pestle for 20min, mixed uniformly, obtained the mixture.

[0067] (2) The mixture is placed in an alumina crucible, the alumina crucible containing the mixture is placed in a muffle furnace, kept at 450℃ in air atmosphere for 8h, and naturally cooled to room temperature to obtain the precursor.

[0068] (3) The precursor is placed in the agate mortar and pestle again for 20min, mixed uniformly, the precursor is placed in an alumina crucible, the alumina crucible containing the precursor is placed in a vacuum tube furnace, vacuumized, kept in nitrogen inert atmosphere at 1350℃ for 10h, the pressure is kept at 1atm, and naturally cooled to room temperature to obtain the powder purple light excitation high thermal stability deep red light fluorescent material.

[0069] Example 5:

[0070] The embodiment provides a kind of purple light excitation, high thermal stability deep red light fluorescent material, its preparation method is basically same with example 1.Different is that in step S1, La:Mg:Ta:Sm = 1.98:1:1:0.02 (molar ratio), in step S2, keep in air atmosphere at 500℃ for 9h, in step S3, keep in helium (He) inert atmosphere at 1350℃ for 10h.The specific steps are as follows:

[0071] (1) Select lanthanum oxide, magnesium oxide, tantalum pentoxide, samarium oxide as starting materials, La:Mg:Ta:Sm = 1.98:1:1:0.02 (molar ratio), respectively according to the measured ratio of four kinds of raw material powder, control the total mass of raw material powder is 10g, each raw material powder is placed in the agate mortar and pestle for 20min, mixed uniformly, obtained the mixture.

[0072] (2) The mixture is placed in an alumina crucible, the alumina crucible containing the mixture is placed in a muffle furnace, kept at 500℃ in air atmosphere for 9h, and naturally cooled to room temperature to obtain the precursor.

[0073] (3) The precursor is placed in the agate mortar and pestle again for 20min, mixed uniformly, the precursor is placed in an alumina crucible, the alumina crucible containing the precursor is placed in a vacuum tube furnace, vacuumized, kept in nitrogen inert atmosphere at 1400℃ for 12h, the pressure is kept at 1atm, and naturally cooled to room temperature to obtain the powder purple light excitation high thermal stability deep red light fluorescent material

[0074] Example 6:

[0075] This embodiment provides a kind of purple light excitation, high thermal stability deep red fluorescent material, its preparation method is substantially same with example 1.Difference is that, in step S1, La:Mg:Ta:Sm=1.97:1:1:0.03 (molar ratio), in step S2, it is calcined in air atmosphere 550 DEG C 10h, in step S3, it is sintered in helium (He) inert atmosphere 1400 DEG C 12h.Specific steps are as follows:

[0076] (1) select lanthanum oxide, magnesium oxide, tantalum pentoxide, samarium oxide as starting material, La:Mg:Ta:Sm=1.97:1:1:0.03 (molar ratio), four kinds of raw material powder are weighed according to the measured ratio, the total mass of raw material powder is controlled to be 10g, each raw material powder is placed in agate mortar and ground for 20min to mix uniformly, to obtain mixture.

[0077] (2) the mixture is placed in alumina crucible, the alumina crucible containing the mixture is placed in muffle furnace, and is calcined in air atmosphere 550 DEG C 10h, and is cooled to room temperature, to obtain precursor.

[0078] (3) the precursor is again placed in agate mortar and ground for 20min to mix uniformly, the precursor is placed in alumina crucible, the alumina crucible containing the precursor is placed in vacuum tube furnace, vacuum is extracted, and is sintered in nitrogen inert atmosphere 1450 DEG C 14h, the pressure is kept 1atm, and is cooled to room temperature, to obtain powder purple light excitation high thermal stability deep red fluorescent material.

[0079] Example 7:

[0080] This embodiment provides a kind of purple light excitation, high thermal stability deep red fluorescent material, its preparation method is substantially same with example 1.Difference is that, in step S1, La:Mg:Sb:Sm=1.99:1:1:0.01 (molar ratio), in step S2, it is calcined in air atmosphere 600 DEG C 11h, in step S3, it is sintered in helium (He) inert atmosphere 1500 DEG C 16h.Specific steps are as follows:

[0081] (1) select lanthanum oxide, magnesium oxide, antimony pentoxide, samarium oxide as starting material, La:Mg:Sb:Sm=1.99:1:1:0.01 (molar ratio), four kinds of raw material powder are weighed according to the measured ratio, the total mass of raw material powder is controlled to be 10g, each raw material powder is placed in agate mortar and ground for 20min to mix uniformly, to obtain mixture.

[0082] (2) Put the mixture into an alumina crucible, and put the alumina crucible containing the mixture into a muffle furnace, calcine at 600 DEG C for 11 h in an air atmosphere, and naturally cool to room temperature to obtain a precursor.

[0083] (3) Put the precursor into a agate mortar again, grind for 20 min, and mix uniformly, put the precursor into an alumina crucible, put the alumina crucible containing the precursor into a vacuum tube furnace, vacuumize, sinter at 1500 DEG C for 16 h in a nitrogen inert atmosphere, keep the pressure at 1 atm, and naturally cool to room temperature to obtain a powder of a purple light excited high-thermal-stability deep red light fluorescent material.

[0084] Example 8:

[0085] The embodiment provides a purple light excited high-thermal-stability deep red light fluorescent material, and a preparation method thereof is basically the same as that in Example 1. The difference lies in that in step S1, La:Mg:Sb:Sm = 1.98:1:1:0.02 (molar ratio), in step S2, calcine at 650 DEG C for 12 h in an air atmosphere, and in step S3, sinter at 1550 DEG C for 18 h in a helium (He) inert atmosphere. The specific steps are as follows:

[0086] (1) Select lanthanum oxide, magnesium oxide, antimony pentoxide and samarium oxide as starting raw materials, and La:Mg:Sb:Sm = 1.98:1:1:0.02 (molar ratio). The four kinds of raw material powders are weighed according to the metering ratio, and the total mass of the raw material powders is controlled to be 10 g. The raw material powders are put into an agate mortar, ground for 20 min, and mixed uniformly to obtain a mixture.

[0087] (2) Put the mixture into an alumina crucible, and put the alumina crucible containing the mixture into a muffle furnace, calcine at 650 DEG C for 12 h in an air atmosphere, and naturally cool to room temperature to obtain a precursor.

[0088] (3) Put the precursor into a agate mortar again, grind for 20 min, and mix uniformly, put the precursor into an alumina crucible, put the alumina crucible containing the precursor into a vacuum tube furnace, vacuumize, sinter at 1550 DEG C for 18 h in a nitrogen inert atmosphere, keep the pressure at 1 atm, and naturally cool to room temperature to obtain a powder of a purple light excited high-thermal-stability deep red light fluorescent material.

[0089] Firstly, the spectral properties of the fluorescent powder in the above examples and comparative examples are tested by using a fluorescence spectrometer (HITACHI F-7500). As shown in FIG. 1, the spectral properties of the fluorescent powder in Example 1 are shown. Figure 1As shown, the results indicate that the deep red phosphor in Example 1 can be excited by near-ultraviolet, violet, or blue light, with the peak of the excitation spectrum located in the violet region and the center wavelength of the emission spectrum at 650 nm. Under excitation by a 410 nm violet light source, the phosphor in Example 1 emits bright red light, with the emission spectrum consisting of multiple narrow emission peaks, the peak of which is located at 650 nm. This demonstrates that the phosphor in Example 1 can be effectively excited by a violet light chip and can be well matched with commercial violet light chips. The deep red phosphors in Examples 2 and 3 can also emit bright red light under excitation by a 410 nm violet light source, with the peak located at 650 nm. In addition, the La2O3-MgO-TA2O5-Sm2O3 fluorescent materials prepared in Examples 4-6 and the La2O3-MgO-Sb2O5-Sm2O3 fluorescent materials prepared in Examples 7-8 can all emit bright red light under excitation by a 410 nm violet light source, indicating that the Sm2O3-MgO-Sb2O5-Sm2O3 fluorescent materials prepared in this invention can emit bright red light. 3+ The doped La2O3-MgO-A2O5-Sm2O3 system of deep red fluorescent materials all have good luminescence properties.

[0090] Secondly, this invention uses X-ray diffraction to test the crystal structure of the fluorescent materials prepared in Examples 1-3. Cu-Kα is used as the target material, and the scanning angle 2θ ranges from 10° to 80°. The resulting XRD patterns are shown below. Figure 2 As shown. From Figure 2 As can be seen from the image, the fluorescent material is consistent with the standard card, indicating that the present invention has produced a pure-phase phosphor, Sm 3+ Ion doping did not have a significant impact on the crystal structure.

[0091] Furthermore, the thermal quenching characteristics of phosphors directly affect the quality of light sources; therefore, phosphors with high thermal stability can effectively mitigate the negative impact of thermal effects on continuous LED lighting. This invention conducts thermal stability tests on the prepared fluorescent material (Hitachi F7000). Figure 3 The results show that, taking Example 1 as an example, the deep red fluorescent material has a luminous intensity of 95.1% at 120°C and 92.3% at 150°C. Therefore, the deep red fluorescent material of the present invention can still maintain a high luminous intensity under the high temperature environment generated by the operation of LED chips, and has excellent thermal quenching resistance.

[0092] To verify that the deep red phosphor material of the present invention can be used to fabricate pc-LED devices, the following electroluminescence test was performed: The deep red phosphor from Example 1 was mixed with commercial BaMgAl... 10 O 17 Eu 2+ Blue phosphor (Easi Electronics Technology (Shanghai) Co., Ltd.) and (Ba,Sr)Si2O4:Eu 2+The green phosphor powder (Easyfine Electronic Technology (Shanghai) Co., Ltd.) was mixed with a mass ratio of 3:1:8 of blue, green and red phosphor powder, and packaged with a 410 nm violet light chip to obtain an LED device. Similarly, the YAG:Ce 3+ The yellow phosphor powder was packaged with a 465 nm blue light LED chip to obtain an LED device. The electroluminescent performance of the above LED device was tested by using a high-precision rapid spectrum radiometer (HAAS-2000, EVERFINE). The results show that the LED device prepared from the phosphor powder of the present application has a high color rendering index of 93.7 and a lower color temperature of 5761 K. In comparison, the commercially available YAG:Ce 3+ The color rendering index of the LED device packaged with the yellow phosphor powder is only 80, and the color temperature is >6000 K.

[0093] In summary, the red light phosphor powder excited by violet light prepared by the present application can be well matched with the existing violet light chip, and the white light LED device prepared therefrom has a high color rendering index and a low color temperature, which can meet the commercial market demand, and has a great development potential in the fields of health lighting such as violet light excitation white light LED, violet light excitation sunlight LED, violet light excitation full spectrum LED, etc.

[0094] The above description of the embodiments is for the purpose of facilitating the understanding and use of the present application by those skilled in the art. Those skilled in the art can obviously make various modifications to the embodiments, and apply the general principles described herein to other embodiments without creative labor. Therefore, the present application is not limited to the above embodiments, and the improvements and modifications made by those skilled in the art based on the disclosure of the present application without departing from the scope of the present application should be within the protection scope of the present application.

Claims

1. A deep red fluorescent material with high thermal stability, characterized in that, The fluorescent material is La2O3-MgO- A The 2O5-Sm2O3 system, in which A Selected from one of Nb, Ta, or Sb; The La2O3-MgO- A In the 2O5-Sm2O3 system, La: Mg: A The molar ratio of Sm is (1.9-1.99): 1: 1:(0.01-0.1).

2. The high thermal stability deep red fluorescent material according to claim 1, characterized in that, The La2O3-MgO- A In the 2O5-Sm2O3 system, La: Mg: A The molar ratio of Sm is 1.99:1:1:0.01 or 1.98:1:1:0.02 or 1.97:1:1:0.

03.

3. The high thermal stability deep red fluorescent material according to claim 1, characterized in that, The La2O3-MgO- A The components in the 2O5-Sm2O3 system, by mass percentage of oxides, are: 52.62% ≤ La2O3 ≤ 64.95%, 6.85% ≤ MgO ≤ 8.07%, 22.60% ≤ A2O5 ≤ 44.27%, and 0.30% ≤ Sm2O3 ≤ 3.49%.

4. The high thermal stability deep red fluorescent material according to claim 1, characterized in that, The excitation spectrum of the fluorescent material is in the ranges of 365-385 nm, 400-410 nm, and 475-500 nm. The optimal excitation spectrum range is 400-410 nm.

5. The high thermal stability deep red fluorescent material according to claim 1, characterized in that, The fluorescent material has an emission center wavelength of 650 nm, accompanied by multi-peak narrowband emission at 550-625 nm and 675-750 nm.

6. A method for preparing a deep red fluorescent material with high thermal stability as described in any one of claims 1-5, characterized in that, Includes the following steps: S1: Weigh out the La-source compound, Mg-source compound, and other components according to the specified proportions. A The source compounds and samarium source compounds are ground and mixed to obtain a mixture; S2: The mixture obtained in S1 is subjected to initial sintering to obtain a precursor; the initial sintering is carried out in an air atmosphere; S3: The precursor obtained in S2 is ground and mixed again and then sintered again to obtain the deep red fluorescent material; the second sintering is carried out in an inert atmosphere, which is selected from one or more of nitrogen, helium and argon.

7. The method for preparing the high thermal stability deep red fluorescent material according to claim 6, characterized in that, In step S1, the La source compound, Mg source compound, A Both the source compound and the samarium source compound are independently selected from one or more of the elemental form, oxide, chloride, sulfide, carbonate, sulfate, phosphate, and nitrate of the corresponding metal element; The grinding time is 5-120 min.

8. The method for preparing the high thermal stability deep red fluorescent material according to claim 6, characterized in that, In step S2, the initial sintering temperature is 200-800 ℃ and the time is 5-24 h.

9. The method for preparing the high thermal stability deep red fluorescent material according to claim 6, characterized in that, In step S3, the secondary grinding time is 5-120 min; The secondary sintering temperature is 1000-1700 ℃, and the time is 1-24 h.

10. An LED light source, prepared from the high thermal stability deep red fluorescent material according to any one of claims 1-5, characterized in that, The LED light source is made by encapsulating deep red phosphor material, blue phosphor, green phosphor and violet chip; The color rendering index of the LED light source is not less than 90.

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