Red light NaTb2Ga3Ge2O12: Eu < 3 + >, Gd < 3 + > fluorescent powder and preparation method thereof

Abstract

The invention discloses red light NaTb2Ga3Ge2O12: Eu < 3 + >, Gd < 3 + > fluorescent powder and a preparation method thereof. The invention relates to red light NaTb2Ga3Ge2O12: Eu < 3 + >, Gd < 3 + > fluorescent powder, which has a chemical composition expression formula of NaTb2 (1-x-y) Ga3Ge2O12: 2xEu < 3 + >, 2yGd < 3 + >, xlt; 0.05, 0 < = y < lt >; and 0.50. The red light NaTb2Ga3Ge2O12: Eu < 3 + >, Gd < 3 + > fluorescent powder provided by the invention has application potential in various fields such as full-spectrum healthy illumination, plant growth illumination, temperature detection, anti-counterfeiting identification and the like.

Description

Technical field:

[0001] The present invention relates to the technical field of luminescent materials, in particular to a red light emitting NaTb2Ga3Ge2O 12 :Eu 3+ ,Gd 3+ Phosphor and preparation method thereof. Background technology:

[0002] The 600-750nm wavelength in the spectrum corresponds to the red light region that can be sensed by human visual cells. Sufficient red light is often considered as an unattainable condition for high-end indoor lighting white light LED devices to achieve a color rendering index greater than 90 and a color temperature lower than 4500K. Therefore, the development of new red phosphors has always been the focus of research in this field. 3+ It is a common red light activated ion, which can obtain red light covering the 580-720nm region in different compound systems. 3+ The red phosphor system as the luminescence center often performs poorly in near-ultraviolet light excitation characteristics because Eu 3+ In the near-ultraviolet region, the transition absorption that its own energy level can provide is not only parity-forbidden but also relatively scattered, and it is unable to fully absorb and utilize the excitation light in the near-ultraviolet region. In order to improve its excitation characteristics, researchers will choose to introduce luminescence centers with better excitation performance in the near-ultraviolet region, such as Tb 3+ , replacing Eu 3+ Absorb energy and use Tb 3+ With Eu 3+ The energy level matching characteristics, through the efficient and thorough energy transfer process of terbium and europium, obtain the Eu 3+ In the existing technology, reports on phosphors with coexistence of terbium and europium are not uncommon, including LiAl(PO3)4:Tb 3+ ,Eu 3+ 、Ba2La3(GeO4)3F:Tb 3+ ,Eu 3+ However, in these phosphors involving terbium and europium, the energy transfer is not complete, resulting in the color coordinates not being able to reach the red light area of ​​the chromaticity diagram and being unable to be used independently as red light phosphors; or due to poor thermal stability of the fluorescence, although the fluorescence is strong at room temperature, it will be reduced as the temperature rises. 3+ The luminous intensity of the luminous flux drops sharply, making it difficult to use in LED devices whose actual operating temperature can often reach 400K. Therefore, it is necessary to develop Eu that can be fully excited by near-ultraviolet light and has good fluorescence thermal quenching characteristics or even abnormal thermal quenching characteristics in the operating temperature range of LED devices. 3+ Red phosphor is of great significance. Summary of the invention:

[0003] The present invention solves the problems existing in the prior art and provides a red light NaTb2Ga3Ge2O 12 :Eu 3+ ,Gd 3+ Phosphor and preparation method thereof, the red light NaTb2Ga3Ge2O 12 :Eu 3+ ,Gd 3+ The phosphor (sodium terbium gallium germanium garnet-based anomalous thermal quenching phosphor) can not only be efficiently excited by 330-385nm near-ultraviolet light and 475-500nm blue light, but also obtain Eu in the 580-720nm orange to deep red light region. 3+ It has multiple characteristic narrow-band fluorescence emissions and can also show abnormal fluorescence thermal quenching characteristics when the temperature reaches 400K. The integrated intensity of the emission spectrum reaches 111% of the room temperature 300K. Under near-ultraviolet light excitation, the red NaTb2Ga3Ge2O 12 :Eu 3+ ,Gd 3+ The quantum efficiency of the phosphor is 71.63%, and the color coordinates are located at (0.63, 0.37).

[0004] The first object of the present invention is to provide a red light NaTb2Ga3Ge2O 12 :Eu 3+ ,Gd 3+ Phosphor, its chemical composition is expressed as: NaTb 2(1-x-y) Ga3Ge2O 12 :2xEu 3+ ,2yGd 3+ , where: 0 <x<0.05,0≤y<0.50。

[0005] The red light NaTb2Ga3Ge2O 12 :Eu 3+ ,Gd 3+ Phosphor uses terbium-europium energy transfer to make Eu 3+ Additional Tb 3+ The excitation spectrum characteristics of Tb 3+ As a matrix element, its high content ensures that the material has sufficient absorption utilization rate for near-ultraviolet light in the 330-385nm range and blue light in the 475-500nm range, and finally obtains high-brightness Eu 3+ Characteristic red light. The red light NaTb2Ga3Ge2O 12 :Eu 3+ ,Gd 3+The phosphor, a novel garnet matrix constructed using sodium, terbium, gallium, and germanium, compared with the traditional garnet isostructural system constructed with aluminum, silicon, and alkaline earth metals, not only has a significantly reduced reaction temperature for solid-phase synthesis, and has no specific pressure and atmosphere requirements during the synthesis process. More importantly, when terbium and europium coexist, as long as the energy level of Tb 3+ is selectively excited, the characteristic red light of Eu 3+ always exhibits abnormal thermal quenching characteristics.

[0006] The second object of the present invention is to provide a preparation method for the red light NaTb2Ga3Ge2O 12 :Eu 3+ ,Gd 3+ phosphor, including the following steps: Weigh raw materials containing sodium, terbium, gallium, germanium, europium, and gadolinium elements according to their chemical compositions. Among them, the molar ratio of each element is Na:Tb:Ga:Ge:Eu:Gd = 1:2 - 2x - 2y:3:2:2x:2y, where: 0 < x < 0.05, 0 ≤ y < 0.50. During the synthesis process, 10% of Ga2O3 needs to be additionally added to compensate for the loss of Ga during the high-temperature reaction. Grind them充分混合均匀 and place them in a reaction vessel, sinter in an atmospheric air atmosphere, and then cool to room temperature. Grind the product to obtain the red light NaTb2Ga3Ge2O 12 :Eu 3+ ,Gd 3+ phosphor.

[0007] Preferably, the raw material containing sodium element is selected from one or more of sodium carbonate, sodium bicarbonate, and sodium oxalate.

[0008] Preferably, the raw material containing terbium element is selected from one or more of terbium oxide, terbium oxalate, terbium carbonate, and terbium nitrate.

[0009] Preferably, the raw material containing gallium element is selected from gallium oxide.

[0010] Preferably, the raw material containing germanium element is selected from germanium oxide.

[0011] Preferably, the raw material containing europium element is selected from one or more of europium oxide, europium oxalate, europium carbonate, and europium nitrate.

[0012] Preferably, the raw material containing gadolinium element is selected from one or more of gadolinium oxide, gadolinium oxalate, gadolinium carbonate, and gadolinium nitrate.

[0013] Preferably, the specific sintering conditions are: sintering temperature 1050°C - 1250°C, sintering time 4 - 8h, and heating rate 5°C / min. The sintering proposed in the present invention is one-step sintering, and the use of Ga2O3 during the reaction process requires a super-stoichiometric ratio to compensate for the loss of Ga during the high-temperature reaction. It should be noted that there is an unclear expression "充分研磨使其混合均匀" in the original text, which is tentatively translated as "Grind them充分混合均匀". You may need to further clarify this part for a more accurate translation.

[0014] The present invention also protects the red light NaTb2Ga3Ge2O 12 :Eu 3+ ,Gd 3+ Application of phosphor in light-emitting devices. The red light NaTb2Ga3Ge2O 12 :Eu 3+ ,Gd 3+ The phosphor has a wide effective excitation range, a wide emission coverage range, and an abnormal thermal quenching characteristic of fluorescence at 400K, which is higher than that at normal temperature 300K. It can be used in many fields such as full-spectrum health lighting, plant growth lighting, temperature detection, anti-counterfeiting identification, etc.

[0015] Compared with the prior art, the present invention has the following advantages:

[0016] 1. Red light NaTb2Ga3Ge2O proposed by the present invention 12 :Eu 3+ ,Gd 3+ The phosphor can be sintered in one step through a solid phase reaction at a temperature range of 1050℃-1250℃ for 4-8h. It has good crystallinity, high luminous brightness and high quantum efficiency.

[0017] 2. Red light NaTb2Ga3Ge2O proposed by the present invention 12 :Eu 3+ ,Gd 3+ The phosphor can be efficiently excited by 330-385nm near-ultraviolet light and 475-500nm blue light and obtain Eu in the 580-720nm orange to deep red light region. 3+ It has multiple characteristic narrow-band fluorescence emissions with the characteristics of a wide excitation range and an excellent red light peak position.

[0018] 3. Red light NaTb2Ga3Ge2O proposed by the present invention 12 :Eu 3+ ,Gd 3+ The phosphor can show abnormal fluorescence thermal quenching characteristics when the temperature reaches 400K, and the integrated intensity of the emission spectrum is higher than the integrated intensity at room temperature 300K, and reaches 111% of the integrated intensity at room temperature 300K. 12 :Eu 3+ ,Gd 3+ The quantum efficiency of the phosphor is 71.63%, and the color coordinates are at (0.63, 0.37). It has application potential in many fields such as full-spectrum health lighting, plant growth lighting, temperature detection, anti-counterfeiting identification, etc. Description of the drawings:

[0019] Figure 1The red light NaTb2Ga3Ge2O prepared in Example 1 12 :Eu 3+ ,Gd 3+ X-ray powder diffraction pattern of phosphor;

[0020] Figure 2 The red light NaTb2Ga3Ge2O prepared in Example 1 12 :Eu 3+ ,Gd 3+ Temperature-dependent fluorescence emission spectra of phosphors;

[0021] Figure 3 The red light NaTb2Ga3Ge2O prepared in Example 1 12 :Eu 3+ ,Gd 3+ Variable temperature fluorescence excitation spectrum of phosphors;

[0022] Figure 4 The red light NaTb2Ga3Ge2O prepared in Example 1 12 :Eu 3+ ,Gd 3+ Quantum efficiency test results of phosphors.

[0023] Figure 5 The red light NaTb2Ga3Ge2O prepared in Example 1 12 :Eu 3+ ,Gd 3+ Chromaticity coordinates of phosphor. Specific implementation method:

[0024] The following examples are provided to further illustrate the present invention, rather than to limit the present invention.

[0025] Unless otherwise defined, all professional terms used hereinafter have the same meaning as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention. Unless otherwise specified, the experimental materials and reagents herein are conventional commercial products in the art.

[0026] Example 1

[0027] Weigh 0.0265g of sodium carbonate (Na2CO3), 0.1121g of terbium oxide (Tb4O7), 0.1546g of gallium oxide (Ga2O3), 0.1046g of germanium oxide (GeO2), 0.0027g of europium oxide (Eu2O3), and 0.0696g of gadolinium oxide (Gd2O3) respectively, grind the above raw materials in an agate mortar, grind them evenly, and then conduct solid phase reaction. After heating to 1200℃ at a rate of 5℃ / min under normal pressure air atmosphere, keep the temperature constant for 4h, wait for it to cool after the end, grind it evenly to obtain red light NaTb2Ga3Ge2O 12 :Eu 3+ ,Gd 3+ Phosphor.

[0028] Red NaTb2Ga3Ge2O 12 :Eu 3+ ,Gd 3+ The X-ray powder diffraction pattern, variable temperature fluorescence emission spectrum and variable temperature fluorescence excitation spectrum of the phosphor are as follows: Figure 1-3 As shown, the quantum efficiency test results are as follows Figure 4 As shown, under near-ultraviolet light excitation, the red NaTb2Ga3Ge2O 12 :Eu 3+ ,Gd 3+ The quantum efficiency of the phosphor is 71.63%, red NaTb2Ga3Ge2O 12 :Eu 3+ ,Gd 3+ The chromaticity coordinate diagram of phosphor is as follows: Figure 5 As shown, the color coordinates are located at (0.63, 0.37).

[0029] Example 2

[0030] Weigh 0.0265g of sodium carbonate (Na2CO3), 0.1495g of terbium oxide (Tb4O7), 0.1546g of gallium oxide (Ga2O3), 0.1046g of germanium oxide (GeO2), 0.0027g of europium oxide (Eu2O3), and 0.0334g of gadolinium oxide (Gd2O3) respectively, grind the above raw materials in an agate mortar, grind them evenly, and then conduct solid phase reaction. After heating to 1050℃ at a rate of 5℃ / min under normal pressure air atmosphere, keep the temperature constant for 8h, wait for it to cool after the end, grind it evenly to obtain red light NaTb2Ga3Ge2O 12 :Eu 3+ ,Gd 3+ Phosphor.

[0031] Example 3

[0032] Weigh 0.0265g of sodium carbonate (Na2CO3), 0.1839g of terbium oxide (Tb4O7), 0.1546g of gallium oxide (Ga2O3), 0.1046g of germanium oxide (GeO2), and 0.0027g of europium oxide (Eu2O3) respectively, grind the above raw materials in an agate mortar, grind them evenly, and then carry out solid phase reaction. Heat to 1150℃ at a rate of 5℃ / min under normal pressure air atmosphere, keep the temperature constant for 6h, wait for it to cool after the end, grind it evenly to obtain red light NaTb2Ga3Ge2O 12 :Eu 3+ ,Gd 3+ Phosphor.

[0033] Example 4

[0034] Weigh 0.0265g of sodium carbonate (Na2CO3), 0.1809g of terbium oxide (Tb4O7), 0.1546g of gallium oxide (Ga2O3), 0.1046g of germanium oxide (GeO2), and 0.0054g of europium oxide (Eu2O3) respectively, grind the above raw materials in an agate mortar, grind them evenly, and then conduct solid phase reaction. Heat to 1250℃ at a rate of 5℃ / min under normal pressure air atmosphere, keep the temperature constant for 4h, wait for it to cool after the end, grind it evenly to obtain red light NaTb2Ga3Ge2O 12 :Eu 3+ ,Gd 3+ Phosphor.

[0035] Example 5

[0036] Weigh 0.0420g of sodium carbonate (NaHCO3), 0.1121g of terbium oxide (Tb4O7), 0.1546g of gallium oxide (Ga2O3), 0.1046g of germanium oxide (GeO2), 0.0081g of europium oxide (Eu2O3), and 0.0638g of gadolinium oxide (Gd2O3) respectively, grind the above raw materials in an agate mortar, grind them evenly, and then conduct solid phase reaction. After heating to 1200℃ at a rate of 5℃ / min under normal pressure air atmosphere, keep the temperature constant for 4h, wait for it to cool after the end, grind it evenly to obtain red light NaTb2Ga3Ge2O 12 :Eu 3+ ,Gd 3+ Phosphor.

[0037] The description of the above embodiments is only used to help understand the technical solution and core ideas of the present invention. It should be pointed out that for technicians in this technical field, several improvements and modifications can be made to the present invention without departing from the principles of the present invention. These improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A red light NaTb2Ga3Ge2O 12 :Eu 3+ ,Gd 3+ The phosphor is characterized in that Its chemical composition is expressed as: NaTb 2(1-x-y) Ga3Ge2O 12 :2xEu 3+ ,2yGd 3+ , where: 0 <x<0.05,0≤y<0.50。 2. The red light NaTb2Ga3Ge2O according to claim 1 12 :Eu 3+ ,Gd 3+ The method for preparing phosphor is characterized in that: It includes the following steps: Weigh the raw materials containing sodium, terbium, gallium, germanium, europium and gadolinium according to their chemical compositions respectively. Among them, the molar ratio of each element is Na:Tb:Ga:Ge:Eu:Gd = 1:2 - 2x - 2y:3:2:2x:2y, where: 0 < x < 0.05, 0 ≤ y < 0.

50. During the synthesis process, 10% of Ga2O3 needs to be added additionally to compensate for the loss of Ga during the high-temperature reaction. Grind them充分研磨使其混合均匀 and put them into a reaction vessel, sinter them in an atmospheric air atmosphere, and then cool them to room temperature. Grind the product to obtain the red light NaTb2Ga3Ge2O 12 :Eu 3+ ,Gd 3+ phosphor. It should be noted that there is an unclear expression "充分研磨使其混合均匀" in the original text, and I have tried my best to translate it according to the context. You may need to check and correct it according to the actual situation.

3. The preparation method according to claim 2, characterized in that: The raw material containing sodium element is selected from at least one of sodium carbonate, sodium bicarbonate and sodium oxalate.

4. The preparation method according to claim 2, characterized in that: The raw material containing terbium element is selected from at least one of terbium oxide, terbium oxalate, terbium carbonate and terbium nitrate.

5. The preparation method according to claim 2, characterized in that: The raw material containing gallium element is selected from gallium oxide.

6. The preparation method according to claim 2, characterized in that: The raw material containing germanium element is selected from germanium oxide.

7. The preparation method according to claim 2, characterized in that: The raw material containing europium element is selected from at least one of europium oxide, europium oxalate, europium carbonate and europium nitrate.

8. The preparation method according to claim 2, characterized in that: The raw material containing gadolinium element is selected from at least one of gadolinium oxide, gadolinium oxalate, gadolinium carbonate and gadolinium nitrate.

9. The preparation method according to claim 2, characterized in that: The specific sintering conditions are: sintering temperature 1050°C-1250°C, sintering time 4-8h.

10. The red light NaTb2Ga3Ge2O according to claim 1 12 :Eu 3+ ,Gd 3+ Application of phosphors in light-emitting devices.

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