Green-light phosphate fluorescent powder and white-light LED light-emitting device
By developing a white LED device that combines cyan phosphate phosphor and red phosphor, the problems of high color temperature and thermal quenching effect in the existing technology have been solved, realizing the application of white LEDs with high color rendering index and high efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- DONGHUA UNIV
- Filing Date
- 2025-11-27
- Publication Date
- 2026-04-24
AI Technical Summary
The lack of red light component in existing white LEDs leads to a high color temperature and insufficient color rendering index. Furthermore, the thermal quenching effect of phosphors affects luminous efficiency, making it difficult to meet the needs of indoor lighting and wide color gamut display.
A cyan phosphate phosphor NaBa2-xAl(P2O7)2:xEu2+ was developed. This phosphor has broad-spectrum excitation characteristics and good thermal stability. Combined with the red phosphor CASN:Eu2+ and a (near)ultraviolet LED chip, a white LED light-emitting device was prepared.
It achieves high brightness and thermal stability white LED with excellent color rendering index (Ra>95) and can maintain 80.71% fluorescence intensity at 150℃, meeting indoor lighting needs.
Smart Images
Figure CN121914723A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of fluorescent materials technology, and specifically relates to a bluish phosphate phosphor and a white LED light-emitting device. Background Technology
[0002] White light emitting diodes (WLEDs), as a new type of solid-state light source, offer advantages over traditional incandescent bulbs and fluorescent lamps, including smaller size, longer lifespan, faster response time, and environmental friendliness. They hold an irreplaceable position in the lighting and display fields, particularly excelling in high efficiency, energy saving, and long lifespan. The realization of white LEDs typically relies on a rational combination of phosphors and LED chips. White light can be obtained by using (n-)ultraviolet (n-UV) chips combined with RGB three-primary-color phosphors. Currently, the main implementation paths for white LEDs include the combination of three-primary-color LED chips and the combination of blue LED chips with Y3Al5O3. 12 :Ce 3+ (YAG) yellow phosphors, and near-ultraviolet LED chips combined with red, green, and blue phosphors, are among the methods used. While the combination of three primary color LED chips can produce high-quality white light, its circuit control is complex, its packaging process requires high precision, and it is prone to color drift over time, making it unsuitable for indoor lighting.
[0003] The combination of blue LEDs and YAG yellow phosphors is currently the mainstream solution for commercial applications. This method has advantages such as high light conversion efficiency, good thermal stability, and simple process. However, due to the lack of red light component, the color temperature is too high and the color rendering index is insufficient. Long-term use may have a negative impact on human sleep and circadian rhythms, making it difficult to meet the needs of indoor lighting and wide color gamut display. In contrast, (near)ultraviolet LED chips combined with RGB three-color phosphors can achieve white light with adjustable color temperature and excellent color rendering, effectively improving the blue light overflow problem in the blue LED+YAG system. Therefore, it is more suitable for indoor lighting and occasions with high requirements for color reproduction, and has become a hot research direction in recent years. Compared with blue light-excited phosphors, research on violet light-excited phosphors is relatively limited. At the same time, the thermal quenching effect of phosphors seriously affects their luminous efficiency and limits their application in LEDs. In addition, red and green phosphors usually have reabsorption problems in the blue region, which leads to energy loss. Currently, this can be solved by combining cyan and red phosphors with (near)ultraviolet LED chips. Therefore, it is crucial to develop cyan fluorescent materials excited by (near)ultraviolet light with high brightness and thermal stability. Summary of the Invention
[0004] The technical problem to be solved by the present invention is to provide a cyanophosphor phosphor and a white LED light-emitting device. The phosphor has the characteristics of broad spectrum excitation and can be well matched with (near) ultraviolet LED chips with different emission wavelengths. The phosphor has excellent light-emitting performance (quantum yield 63.76%) and good thermal stability, and can maintain 80.71% of the fluorescence intensity at room temperature at 150℃.
[0005] This invention provides a bluish phosphate phosphor, wherein the phosphor has the following general formula: NaBa 2-x Al(P2O7)2:xEu 2+ , where 0.01≤x≤0.06.
[0006] Furthermore, the emission peak of the cyanophosphate phosphor is located at 455 nm.
[0007] This invention also provides a method for preparing cyanobacterial phosphate phosphor, comprising the following steps:
[0008] (1) Weigh out the appropriate proportions of sodium salt, aluminum oxide, barium salt, phosphate and europium oxide as reactant raw materials according to the stoichiometric ratio;
[0009] (2) Grind the above reactants evenly to obtain a mixed powder; transfer the mixed powder to a crucible and then place it in a muffle furnace at 300-500℃ for 5-15 hours. After the reaction is completed, grind it again and put it into a mold to press it into a disc.
[0010] (3) Transfer the disc to a crucible and then place it in a tube furnace and keep it at 600-700℃ for 4-6 hours in a reducing atmosphere. After the reaction is complete, grind the product again to obtain bluish phosphor phosphate.
[0011] Preferably, the sodium salt in step (1) is sodium carbonate; the barium salt is barium fluoride or barium carbonate; and the phosphate is diammonium hydrogen phosphate or diammonium dihydrogen phosphate.
[0012] Preferably, the pressing pressure in step (2) is 10-20 MPa and the pressing time is 1-10 min.
[0013] Preferably, the reducing atmosphere in step (3) consists of 10%-20% H2 and 80%-90% N2 by volume.
[0014] The present invention also provides a white LED light-emitting device, including a packaging substrate, a near / ultraviolet LED chip, the aforementioned cyan phosphate phosphor, and a red phosphor.
[0015] Preferably, the red phosphor is CASN:Eu 2+ Fluorescent powder.
[0016] The present invention also provides a method of using a white LED light-emitting device, comprising the following steps:
[0017] After uniformly mixing cyan phosphate phosphor and red phosphor with epoxy resin or silicone, the mixture is applied to the surface of an LED chip by dispensing. Near / ultraviolet light is used to excite the phosphor and generate composite white light.
[0018] Beneficial effects
[0019] The method for preparing the cyan phosphate phosphor of this invention is simple, environmentally friendly, and uses inexpensive raw materials. It emits cyan light with a peak value of 455 nm under (near)ultraviolet light excitation. This phosphor exhibits broad-spectrum excitation characteristics, allowing for good matching with (near)ultraviolet LED chips of different emission wavelengths. The phosphor demonstrates excellent luminescence performance (quantum yield 63.76%) and good thermal stability, maintaining 80.71% of its room-temperature fluorescence intensity at 150 °C. By combining the cyan phosphate phosphor of this invention with existing commercially available red phosphors and (near)ultraviolet LED chips, a white LED device was fabricated. This white LED device exhibits high luminous efficiency and an excellent color rendering index (Ra > 95), meeting the needs of indoor lighting. Attached Figure Description
[0020] Figure 1 The NaBa2Al(P2O7)2 prepared in Example 1: 0.01Eu 2+ X-ray diffraction pattern of phosphor.
[0021] Figure 2 The NaBa2Al(P2O7)2 prepared in Example 1: 0.01Eu 2+ Excitation spectrum (a) and emission spectrum (b) of the phosphor.
[0022] Figure 3 The NaBa2Al(P2O7)2:0.02Eu prepared in Example 2 2+ X-ray diffraction pattern of phosphor.
[0023] Figure 4 The NaBa2Al(P2O7)2:0.02Eu prepared in Example 2 2+ Excitation spectrum (a) and emission spectrum (b) of the phosphor.
[0024] Figure 5 The NaBa2Al(P2O7)2:0.03Eu prepared in Example 3 2+ X-ray diffraction pattern of phosphor.
[0025] Figure 6The NaBa2Al(P2O7)2:0.03Eu prepared in Example 3 2+ Excitation spectrum (a), emission spectrum (b), fluorescence quantum efficiency diagram (c), and temperature-dependent fluorescence spectrum (d) of the phosphor.
[0026] Figure 7 The NaBa2Al(P2O7)2:0.04Eu prepared in Example 4 2+ X-ray diffraction pattern of phosphor.
[0027] Figure 8 The NaBa2Al(P2O7)2:0.04Eu prepared in Example 4 2+ Excitation spectrum (a) and emission spectrum (b) of the phosphor.
[0028] Figure 9 The NaBa2Al(P2O7)2:0.05Eu prepared in Example 5 2+ X-ray diffraction pattern of phosphor.
[0029] Figure 10 The NaBa2Al(P2O7)2:0.05Eu prepared in Example 5 2+ Excitation spectrum (a) and emission spectrum (b) of the phosphor.
[0030] Figure 11 The NaBa2Al(P2O7)2:0.06Eu prepared in Example 6 2+ X-ray diffraction pattern of phosphor.
[0031] Figure 12 The NaBa2Al(P2O7)2:0.06Eu prepared in Example 6 2+ Excitation spectrum (a) and emission spectrum (b) of the phosphor.
[0032] Figure 13 The image shows the electroluminescence spectrum of the white LED light-emitting device prepared in Example 7.
[0033] Figure 14 The NaBa2Al(P2O7)2:0.03Eu prepared in Example 3 2+ Performance diagram of phosphor. Detailed Implementation
[0034] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.
[0035] The instruments used for testing the relevant performance of the samples obtained in the following examples and comparative examples are as follows:
[0036] 1. The crystal structure and phase analysis of the samples were performed using a Rigaku D / max-2500 X-ray diffractometer from Japan, with Cu target Ka1 radiation (λ=1.5406 Å) as the radiation source.
[0037] 2. The excitation and emission spectra of the samples were tested using an F-4600 fluorescence spectrometer manufactured by Hitachi, Japan.
[0038] 3. The temperature-dependent spectra of the samples were measured using an Edinburgh FLS1000 fluorescence spectrometer.
[0039] 4. The internal quantum efficiency of the samples was measured using a Hamamatsu Quantaurus-QY plus fluorescence spectrometer with an integrating sphere.
[0040] Example 1
[0041] Weigh out Na2CO3 (0.1326 g), Al2O3 (0.1287 g), BaF2 (0.8723 g), (NH4)2HPO4 (1.3407 g), and Eu2O3 (0.0044 g). Mix the above raw materials and grind them to make the raw materials uniform. Then, put the mixed powder into an alumina crucible and place it in a muffle furnace. Heat it to 400 °C and keep it at that temperature for 10 h. After cooling, re-grind the mixture and put it into a cylindrical mold with a diameter of 10 mm. Press it under a pressure of 10 MPa for 5 minutes to make a disc. The disc was transferred to an alumina crucible and heated to 650 °C at a heating rate of 5 °C / min in a horizontal tube furnace with a reducing atmosphere (composed of 10% H2 and 90% N2 by volume; the composition and content of the reducing atmosphere in the following examples are the same as those in this example). The furnace was then allowed to cool naturally to below 100 °C before being removed. The resulting product was then thoroughly ground to obtain sample S1.
[0042] The prepared sample S1 was subjected to crystal structure and phase analysis. XRD pattern as shown... Figure 1 As shown, by Figure 1 It can be seen that the main crystalline phase of sample S1 obtained in this embodiment is NaBa2Al(P2O7)2:0.01Eu. 2+ No other features were observed.
[0043] The fluorescence properties of the prepared sample S1 were tested, and the results are as follows: Figure 2 As shown. By Figure 2 (a) It can be seen that the sample S1 prepared in this embodiment can be effectively excited by (near) ultraviolet light of about 320-400 nm; Figure 2 (b) It can be seen that the sample S1 prepared in this embodiment can emit cyan light with a peak wavelength of 455 nm after being excited by 320 nm (near) ultraviolet light.
[0044] Example 2
[0045] Weigh out Na2CO3 (0.1326 g), Al2O3 (0.1287 g), BaF2 (0.8723 g), (NH4)2HPO4 (1.3407 g), and Eu2O3 (0.0088 g). Mix the above raw materials and grind them to make the raw materials uniform. Then, put the mixed powder into an alumina crucible and place it in a muffle furnace. Heat it to 400 °C and keep it at that temperature for 10 h. After cooling, re-grind the mixture and put it into a cylindrical mold with a diameter of 10 mm. Press it under a pressure of 10 MPa for 5 minutes to make a disc. The disc was transferred to an alumina crucible and heated to 650 °C at a heating rate of 5 °C / min in a horizontal tube furnace with a reducing atmosphere (composed of 10% H2 and 90% N2 by volume; the composition and content of the reducing atmosphere in the following examples are the same as those in this example). The furnace was then allowed to cool naturally to below 100 °C before being removed. The resulting product was then thoroughly ground to obtain sample S2.
[0046] The obtained sample S2 was subjected to crystal structure and phase analysis. XRD patterns are shown below. Figure 3 As shown, by Figure 3 It can be seen that the main crystalline phase of sample S2 obtained in this embodiment is NaBa2Al(P2O7)2:0.02Eu. 2+ No other features were observed.
[0047] The fluorescence properties of the prepared sample S2 were tested, and the results are as follows: Figure 4 As shown. By Figure 4 (a) It can be seen that the sample S2 prepared in this embodiment can be effectively excited by (near) ultraviolet light of about 320-400 nm; Figure 4 (b) It can be seen that the sample S2 prepared in this embodiment can emit cyan light with a peak wavelength of 455 nm after being excited by 320 nm (near) ultraviolet light.
[0048] Example 3
[0049] Weigh out Na2CO3 (0.1326 g), Al2O3 (0.1287 g), BaF2 (0.8723 g), (NH4)2HPO4 (1.3407 g), and Eu2O3 (0.0132 g). Mix the above raw materials and grind them to make the raw materials uniform. Then, put the mixed powder into an alumina crucible and place it in a muffle furnace. Heat it to 400 °C and keep it at that temperature for 10 h. After cooling, re-grind the mixture and put it into a cylindrical mold with a diameter of 10 mm. Press it under a pressure of 10 MPa for 5 minutes to make a disc. The disc was transferred to an alumina crucible and heated to 650 °C at a heating rate of 5 °C / min in a horizontal tube furnace with a reducing atmosphere (composed of 10% H2 and 90% N2 by volume; the composition and content of the reducing atmosphere in the following examples are the same as those in this example). The furnace was then allowed to cool naturally to below 100 °C before being removed. The resulting product was then thoroughly ground to obtain sample S3.
[0050] The obtained sample S3 was subjected to crystal structure and phase analysis. XRD pattern as shown... Figure 5 As shown, by Figure 5 It can be seen that the main crystalline phase of sample S3 obtained in this embodiment is NaBa2Al(P2O7)2:0.03Eu. 2+ No other features were observed.
[0051] The fluorescence properties of the prepared sample S3 were tested, and the results are as follows: Figure 6 As shown. By Figure 6 (a) It can be seen that the sample S3 prepared in this embodiment can be effectively excited by (near) ultraviolet light of about 320-400 nm; Figure 6 (b) It can be seen that the sample S3 prepared in this embodiment, after being excited by near-ultraviolet light at 320 nm, can emit cyan light with a peak wavelength of 455 nm; Figure 6 (c) It can be seen that the sample S3 prepared in this embodiment has excellent resistance to thermal quenching; at 150 °C, its fluorescence intensity can maintain 80.71% of that at room temperature. Figure 6 (d) It can be seen that the fluorescence quantum yield of sample S3 prepared in this embodiment is 63.76% under (near) ultraviolet light excitation at 320 nm.
[0052] Depend on Figure 14 It can be seen that the optimal doping concentration for sample S3 is NaBa2Al(P2O7)2:0.03Eu. 2+Sample S3 can be effectively excited by (near) ultraviolet light, with an optimal excitation wavelength of 320 nm, emitting cyan light with a peak wavelength of 455 nm; under (near) ultraviolet light excitation at 320 nm, the fluorescence quantum yield is 63.76%; the prepared sample S3 was then compared with the commercial red phosphor CASN:Eu 2+ The WLED prepared by the mixture has a color rendering index of Ra=95.6 and a correlated color temperature of 5723 K.
[0053] Example 4
[0054] Weigh out Na2CO3 (0.1326 g), Al2O3 (0.1287 g), BaF2 (0.8723 g), (NH4)2HPO4 (1.3407 g), and Eu2O3 (0.0176 g). Mix the above raw materials and grind them to make the raw materials uniform. Then, put the mixed powder into an alumina crucible and place it in a muffle furnace. Heat it to 400 °C and keep it at that temperature for 10 h. After cooling, re-grind the mixture and put it into a cylindrical mold with a diameter of 10 mm. Press it under a pressure of 10 MPa for 5 minutes to make a disc. The disc was transferred to an alumina crucible and heated to 650 °C at a heating rate of 5 °C / min in a horizontal tube furnace with a reducing atmosphere (composed of 10% H2 and 90% N2 by volume; the composition and content of the reducing atmosphere in the following examples are the same as those in this example). The furnace was then allowed to cool naturally to below 100 °C before being removed. The resulting product was then thoroughly ground to obtain sample S4.
[0055] The obtained sample S4 was subjected to crystal structure and phase analysis. XRD pattern as shown... Figure 7 As shown, by Figure 7 It can be seen that the main crystalline phase of sample S4 obtained in this embodiment is NaBa2Al(P2O7)2:0.04Eu. 2+ No other features were observed.
[0056] The fluorescence properties of the prepared sample S4 were tested, and the results are as follows: Figure 8 As shown. By Figure 8 (a) It can be seen that the sample S4 prepared in this embodiment can be effectively excited by (near) ultraviolet light of about 320-400 nm; Figure 8 (b) It can be seen that the sample S4 prepared in this embodiment can emit cyan light with a peak wavelength of 455 nm after being excited by 320 nm (near) ultraviolet light.
[0057] Example 5
[0058] Weigh out Na2CO3 (0.1326 g), Al2O3 (0.1287 g), BaF2 (0.8723 g), (NH4)2HPO4 (1.3407 g), and Eu2O3 (0.022 g). Mix the above raw materials and grind them to make the raw materials uniform. Then, put the mixed powder into an alumina crucible and place it in a muffle furnace. Heat it to 400 °C and keep it at that temperature for 10 h. After cooling, re-grind the mixture and put it into a cylindrical mold with a diameter of 10 mm. Press it under a pressure of 10 MPa for 5 minutes to make a disc. The disc was transferred to an alumina crucible and heated to 650 °C at a heating rate of 5 °C / min in a horizontal tube furnace with a reducing atmosphere (composed of 10% H2 and 90% N2 by volume; the composition and content of the reducing atmosphere in the following examples are the same as those in this example). The furnace was then allowed to cool naturally to below 100 °C before being removed. The resulting product was then thoroughly ground to obtain sample S5.
[0059] The obtained sample S5 was subjected to crystal structure and phase analysis. XRD pattern as shown... Figure 9 As shown, by Figure 9 It can be seen that the main crystalline phase of sample S5 obtained in this embodiment is NaBa2Al(P2O7)2:0.05Eu. 2+ No other features were observed.
[0060] The fluorescence properties of the prepared sample S5 were tested, and the results are as follows: Figure 10 As shown. By Figure 10 (a) It can be seen that the sample S5 prepared in this embodiment can be effectively excited by (near) ultraviolet light of about 320-400 nm; Figure 10 (b) It can be seen that the sample S5 prepared in this embodiment can emit cyan light with a peak wavelength of 455 nm after being excited by 320 nm (near) ultraviolet light.
[0061] Example 6
[0062] Weigh out Na2CO3 (0.1326 g), Al2O3 (0.1287 g), BaF2 (0.8723 g), (NH4)2HPO4 (1.3407 g), and Eu2O3 (0.0246 g). Mix the above raw materials and grind them to make the raw materials uniform. Then, put the mixed powder into an alumina crucible and place it in a muffle furnace. Heat it to 400 °C and keep it at that temperature for 10 h. After cooling, re-grind the mixture and put it into a cylindrical mold with a diameter of 10 mm. Press it under a pressure of 10 MPa for 5 minutes to make a disc. The disc was transferred to an alumina crucible and heated to 650 °C at a heating rate of 5 °C / min in a horizontal tube furnace with a reducing atmosphere (composed of 10% H2 and 90% N2 by volume; the composition and content of the reducing atmosphere in the following examples are the same as those in this example). The furnace was then allowed to cool naturally to below 100 °C before being removed. The resulting product was then thoroughly ground to obtain sample S6.
[0063] The obtained sample S6 was subjected to crystal structure and phase analysis. XRD patterns are shown below. Figure 11 As shown, by Figure 11 It can be seen that the main crystalline phase of sample S6 obtained in this embodiment is NaBa2Al(P2O7)2:0.06Eu. 2+ No other features were observed.
[0064] The fluorescence properties of the prepared sample S6 were tested, and the results are as follows: Figure 12 As shown. By Figure 12 (a) It can be seen that the sample S6 prepared in this embodiment can be effectively excited by (near) ultraviolet light of about 320-400 nm; Figure 12 (b) It can be seen that the sample S6 prepared in this embodiment can emit cyan light with a peak wavelength of 455nm after being excited by 320nm (near) ultraviolet light.
[0065] Example 7
[0066] This embodiment provides a white LED light-emitting device, comprising a packaging substrate, a (near)ultraviolet LED packaging chip, and a phosphor capable of effectively absorbing the light emitted by the LED chip and emitting cyan and red light; wherein, the cyan phosphor is the cyan phosphor for white LEDs described in Embodiment 3 above, with the chemical formula NaBa2Al(P2O7)2:0.03Eu. 2+ The peak emission wavelength of the near-ultraviolet LED packaged chip is 320 nm, and the red phosphor is a commercially available CASN: Eu. 2+ Fluorescent powder.
[0067] LED light-emitting devices generate white light through the following principle: the LED chip is fixed on the packaging substrate, cyan phosphor and red phosphor are mixed evenly with epoxy resin or silicone, and then coated onto the surface of the LED chip by dispensing. The bicolor light generated by the phosphor is excited by near-ultraviolet light and combined to obtain white light. Figure 13 The electroluminescence spectrum of the fabricated white LED light-emitting device is shown. Its color coordinates are (0.3005, 0.3106), its color temperature is 5723 K, and its color rendering index is 95.6 at a current of 20 mA, which can meet the needs of indoor lighting.
Claims
1. A bluish-green phosphate phosphor, characterized in that, The phosphor has the following general formula: NaBa 2-x Al(P2O7)2:xEu 2+ , where 0.01≤x≤0.
06.
2. A method for preparing the bluish-green phosphate phosphor as described in claim 1, characterized in that, Includes the following steps: (1) Weigh out the appropriate proportions of sodium salt, aluminum oxide, barium salt, phosphate and europium oxide as reactant raw materials according to the stoichiometric ratio; (2) Grind the above reactants evenly to obtain a mixed powder; transfer the mixed powder to a crucible and then place it in a muffle furnace at 300-500℃ for 5-15 hours. After the reaction is completed, grind it again and put it into a mold to press it into a disc. (3) Transfer the disc to a crucible and then place it in a tube furnace and keep it at 600-700℃ for 4-6 hours in a reducing atmosphere. After the reaction is complete, grind the product again to obtain bluish phosphor phosphate.
3. The preparation method according to claim 2, characterized in that, The sodium salt in step (1) is sodium carbonate; the barium salt is barium fluoride or barium carbonate; and the phosphate salt is diammonium hydrogen phosphate or diammonium dihydrogen phosphate.
4. The preparation method according to claim 2, characterized in that, The pressing pressure in step (2) is 10-20 MPa, and the pressing time is 1-10 min.
5. The preparation method according to claim 2, characterized in that, The reducing atmosphere in step (3) consists of 10%-20% H2 and 80%-90% N2 by volume.
6. A white LED light-emitting device, characterized in that, It includes a packaging substrate, a near / ultraviolet LED chip, a cyan phosphate phosphor as described in claim 1, and a red phosphor.
7. The white LED light-emitting device according to claim 6, characterized in that, The red phosphor is CASN:Eu 2+ Fluorescent powder.
8. A method of using the white LED light-emitting device as described in claim 6, characterized in that, Includes the following steps: After uniformly mixing cyan phosphate phosphor and red phosphor with epoxy resin or silicone, the mixture is applied to the surface of an LED chip by dispensing. Near / ultraviolet light is used to excite the phosphor and generate composite white light.