CN107987828A - A kind of mayenite structure fluorescent powder of LED white light emissions - Google Patents
A kind of mayenite structure fluorescent powder of LED white light emissions Download PDFInfo
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- CN107987828A CN107987828A CN201711473787.3A CN201711473787A CN107987828A CN 107987828 A CN107987828 A CN 107987828A CN 201711473787 A CN201711473787 A CN 201711473787A CN 107987828 A CN107987828 A CN 107987828A
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- fluorescent powder
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- C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
- C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
- C09K11/77—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing rare earth metals
- C09K11/7706—Aluminates
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Abstract
The present invention relates to a kind of mayenite structure fluorescent powder of LED white light emissions, the chemical structural formula of the fluorescent powder are as follows：Ca12Al14O32A2:xDy3+, wherein A is one kind in Cl, F, and x is Dy3+Substitute Ca2+Molar ratio, value range is 0.01≤x≤0.6.The fluorescent powder mixes Dy for single-matrix list3+White emitting fluorescent powder, fluorescent powder have the advantages that fluorescence lifetime length and photochromism it is good, can be applied near ultraviolet LED excitation.
Description
Technical field
The present invention relates to rare earth luminescent material technical field, and in particular to a kind of mayenite structure of LED white light emissions
Fluorescent powder.
Background technology
Light emitting diode (LED) is acknowledged as the new light sources of 21st century, because it is with energy conservation and environmental protection, luminous efficiency
The advantages such as high, colour rendering is good, long lifespan, brightness height, fast response time, can not only substitute conventional illumination device, can also apply
In fields such as large display screen, the backlight of electronic equipment, thermoluminescence detections.The realization of white light LEDs generally has three kinds of methods：
(1) blue-light LED chip excitation YAG yellow fluorescent powders, the yellowish green photosynthesis white light sent by LED blue lights and fluorescent powder；(2) pass through
The three primary colours multi-chip illuminated in combination synthesis white light of LED RGBs；(3) ultraviolet leds chip excites three kinds of fluorescent powders to send three
Primary colours synthesize white light.Fluorescent powder prepared by first method, which exists, lacks red band, and colour rendering index is low, and correlated colour temperature height etc. lacks
Fall into.The three primary colours light decay difference of second method difference chip causes that colour temperature is unstable, control circuit is more complicated, cost is higher.
The problem of the third is most common method, but a variety of matrix mixed fluorescent powders are reabsorbed in the presence of proportioning regulation and control and color is (such as red
Color fluorescent powder, which can not only absorb ultraviolet light, can also absorb blue light).Compared to a variety of matrix mixed fluorescent powders, single-substrate white fluorescence
The glow color of powder is determined that such fluorescent powder colour stability is good, and single-substrate white fluorescent powder is by its spectrum
Single compound, the energy loss in energy transfer process is smaller, and luminous efficiency is higher, and cost is relatively low.Therefore, single-substrate white
Fluorescent powder is the following most potential fluorescent powder in white-light illuminating field.
Wherein, the bismuth phosphate list of patent CN106590651A reports mixes Dy3+White emitting fluorescent powder is to use Co deposited synthesis
, although the light-emitting phosphor intensity is high, nitric acid is employed in preparation as one of raw material, cost is higher and technique is answered
It is miscellaneous, it is not suitable for industrialization production；N.ShantaSingh et al. is prepared for YVO4：Dy3+Nano particle, synthesizes at 900 DEG C
YVO4：0.02Dy3+Fluorescence lifetime be only 100 μ s (ChemicalPhysicsLetters480 (2009)：237-242)；Sun Yan
Dragon has synthesized Sr with high temperature solid-state method3B2O6：Dy3+Fluorescent powder, sample shine in white light field, its chromaticity coordinates be (0.2100,
0.2160), by adulterating the Eu of various concentrations3+After adjusting photochromism, the fluorescent powder it is attainable closest to standard white light
Chromaticity coordinates is (0.2960,0.2510), and still having certain distance from pure white light coordinates (0.3333,0.3333), (Sun Yan dragons is single
The preparation of matrix white LED fluorescent powders and luminescent properties research [D] Harbin University of Science and Technologys (master thesis),
2014)。
Ca12Al14O32A2(A=Cl, F) is a kind of host material with mayenite structure, belongs to cubic structure, space
Group is I-43d.There is the rare earth ion doped Ca of many document reports at present12Al14O32A2It is red, indigo prepared by (A=Cl, F)
Color fluorescent powder.However, so far, the fluorescence that the mayenite structural matrix not adulterated singly also in the prior art emits white light
Powder.
The content of the invention
It is an object of the present invention to provide a kind of mayenite structure fluorescent powder of LED white light emissions.The fluorescent powder is single
Matrix list mixes Dy3+White emitting fluorescent powder, fluorescent powder have the advantages that fluorescence lifetime length and photochromism it is good, can be applied near ultraviolet
LED is excited.
In order to achieve the above object, present invention employs following technical solution：
A kind of mayenite structure fluorescent powder of LED white light emissions, the chemical structural formula of the fluorescent powder are as follows：
Ca12Al14O32A2:xDy3+, wherein A is one kind in Cl, F, and x is Dy3+Substitute Ca2+Molar ratio, value range
For 0.01≤x≤0.6.
A kind of preparation method of the mayenite structure fluorescent powder of above-mentioned LED white light emissions, this method comprise the following steps：
1) with CaO, Al2O3、Dy2O3、CaCl2Or CaF2For raw material, and accurately according to Ca12Al14O32A2:xDy3+(A=
Cl or F) shown in stoichiometric ratio weigh above-mentioned raw materials, raw material uniformly mixed to be put into mortar be fully ground；
2) raw material being fully ground is put into corundum crucible, corundum crucible is put into Muffle furnace in air atmosphere
High temperature process heat is carried out, calcining heat is 1100-1200 DEG C, when calcining 12-16 is small；
3) corundum crucible is taken out after Muffle furnace is cooled to room temperature, obtained sample is fully ground, obtains LED use
The mayenite structure fluorescent powder of white light emission, the fluorescent powder are single ion Dy3+Adulterate the white emitting fluorescent powder of mayenite base.
Compared with prior art, the beneficial effects of the invention are as follows：
(1) it is the white emitting fluorescent powder of single-matrix type list doping compared to combination fluorescent powder system, the application, can overcomes
Combination fluorescent powder system photochromic decline speed difference and color re-absorption problem, reduce cost.
(2) raw material of fluorescent powder of the present invention are cheap, safe and environment-friendly, and preparation process is simple, and cost is relatively low, suitable for work
Industry metaplasia is produced.
(3) after tested, the fluorescence lifetime of fluorescent powder of the present invention can reach more than 200 μ s, wherein Ca12Al14O32Cl2:
0.5Dy3+Fluorescence lifetime be 416.2 μ s, fluorescence lifetime is longer.
(4)Ca12Al14O32Cl2:0.5Dy3+With good chromaticity coordinates position (0.2960,0.3367), standard white is closer to
Photochromic coordinate (0.3333,0.3333), has preferably photochromism.
(5) fluorescent powder can launch strong white light under the excitation of black light, therefore can be used near ultraviolet excitated
White light LEDs.
Brief description of the drawings
Fig. 1 is the X-ray diffractogram of phosphor material powder sample in the embodiment of the present invention 1.
Fig. 2 is the transmitting of phosphor material powder sample and excitation spectrum in the embodiment of the present invention 1.
Fig. 3 is CIE chromaticity coordinates figure of the phosphor material powder sample under 383nm excitations in the embodiment of the present invention 1,2.
Fig. 4 is the X-ray diffractogram of phosphor material powder sample in the embodiment of the present invention 2.
Fig. 5 is the transmitting of phosphor material powder sample and excitation spectrum in the embodiment of the present invention 2.
Fig. 6 is the fluorescence decay curve of phosphor material powder sample in the embodiment of the present invention 1,2.
Embodiment
Below in conjunction with the accompanying drawings, the present invention is described in further detail.
The mayenite structure fluorescent powder of LED white light emissions of the present invention, the chemical structural formula of the fluorescent powder are as follows：
Ca12Al14O32A2:xDy3+,
Wherein A is one kind in Cl, F, and x is Dy3+With respect to Ca12Al14O32A2Molar ratio, value range for 0.01≤x≤
0.6。
The Dy in the composition3+It instead of Ca2+Case, due to Dy3+Doping be micro, therefore have ignored substituted
Ca2+.Matrix middle-jiao yang, function of the spleen and stomach ion site number is certain, so Ca2+With doping Dy3+Total amount it is identical with cation lattice digit.
Embodiment 1
The mayenite structure fluorescent powder of the present embodiment LED white light emissions, the chemical structural formula of the fluorescent powder are as follows：
Ca12Al14O32Cl2:0.5Dy3+。
Preparation method is：Weigh CaO (analysis is pure) 1.2338g, Al2O3(analysis is pure) 1.4274g, CaCl2(analysis is pure)
0.2220g、Dy2O3(99.99%) 0.1850g.Above-mentioned raw materials are uniformly mixed after being put into and being fully ground in mortar, be put into
In corundum crucible, high temperature process heat is then carried out in air atmosphere.The calcining heat of the present embodiment is arranged to 1200 DEG C, forges
When the burning time is 15 small.Sample is taken out to be fully ground by Muffle furnace after being cooled to room temperature obtains LED white light emissions
Mayenite structure fluorescent powder sample, the chemical structural formula of the fluorescent powder is Ca12Al14O32Cl2:0.5Dy3+。
With the phase structure of D8AdvanceX x ray diffractometer x test samples, by the sample and Ca12Al14O32Cl2Standard
The contrast of X-ray diffraction spectrogram (PDF#45-0568) is (as shown in Figure 1) to be understood, sample is Ca12Al14O32Cl2It is single-phase,
0.5mol%Dy3+Doping do not change Ca12Al14O32Cl2Lattice structure.
With F-7000 sepectrophotofluorometers test at room temperature the emission spectrum of the sample and excitation spectrum (such as Fig. 2 institutes
Show), as seen from the figure, in the case where 576nm monitors wavelength, excitation peak respectively positioned at 320,344,360,383,424,453nm, it is right respectively
Answer Dy3+'s6H15/2-4K15/2、6H15/2-6P7/2、6H15/2-6P5/2、6H15/2-4I13/2、6H15/2-4G11/2、6H15/2-4I15/2Transition,
Wherein positioned at 344nm (6H15/2-6P7/2) peak be highest peak.Under the excitation of near ultraviolet 383nm, emission spectrum has two sections of transmittings
Peak, positioned at 478 and 580nm, corresponds to respectively4F9/2-6H15/2With4F9/2-6H13/2Transition, white light are exactly the compound hair of the two transition
Light.It is (0.2960,0.3367) (as shown in Figure 3) to calculate its chromaticity coordinate by emission spectrum, position in white light field and
It is closer to standard white light (0.3333,0.3333).The fluorescence that the sample is tested using FL3-22 stable state transient state Fluorescence Spectrometer is declined
Subtract curve (as shown in Figure 6), by the secondary exponential fitting to attenuation curve, the mean fluorecence service life of the sample can be obtained
416.2μs。
Embodiment 2
The mayenite structure fluorescent powder of the present embodiment LED white light emissions, the chemical structural formula of the fluorescent powder are as follows：
Ca12Al14O32F2:0.03Dy3+。
Preparation method is：Weigh CaO (analysis is pure) 1.2338g, Al2O3(analysis is pure) 1.4274g, CaF2(analysis is pure)
0.1562g、Dy2O3(99.99%) 0.0111g.Corundum crucible is put into after above-mentioned raw materials are uniformly mixed and are fully ground
In, high temperature process heat is then carried out in air atmosphere.The calcining heat of the embodiment is arranged to 1200 DEG C, and the time is small for 15
When.Sample is taken out to be fully ground by Muffle furnace after being cooled to room temperature obtains sample Ca12Al14O32F2:0.03Dy3+。
With the phase structure of D8AdvanceX x ray diffractometer x test samples, by the sample and Ca12Al14O32F2Standard x
The contrast of x ray diffraction spectrogram (PDF#70-1353) is (as shown in Figure 4) to be understood, sample is Ca12Al14O32F2It is single-phase,
0.03mol%Dy3+Doping do not change Ca12Al14O32F2Lattice structure.Existed with the test of F-7000 sepectrophotofluorometers
The emission spectrum of the sample and excitation spectrum (as shown in Figure 5) at room temperature, as seen from the figure, in the case where 576nm monitors wavelength, excitation peak
Respectively positioned at 323,345,362,383,423,453nm, correspond to Dy respectively3+'s6H15/2-4K15/2、6H15/2-6P7/2、6H15/2-6P5/2、6H15/2-4I13/2、6H15/2-4G11/2、6H15/2-4I15/2Transition, wherein positioned at 345nm (6H15/2-6P7/2) peak be most strong
Peak.Under the excitation of near ultraviolet 383nm, emission spectrum has two sections of emission peaks, positioned at 478 and 575nm, corresponds to respectively4F9/2-6H15/2With4F9/2-6H13/2Transition, white light are exactly the recombination luminescence of the two transition.Its chromaticity coordinate is calculated by emission spectrum
For (0.2715,0.2774) (as shown in Figure 3), position is in white light field.Tested using FL3-22 stable state transient states Fluorescence Spectrometer
The fluorescence decay curve (as shown in Figure 6) of the sample, by the secondary exponential fitting to attenuation curve, can obtain the sample
220.8 μ s of mean fluorecence service life.
Dy3+Mainly there are two kinds of transmittings in visible region：It is a kind of in blue region, belong to4F9/2→6H15/2(475nm) jumps
Move；It is another in yellow region, belong to4F9/2→6H13/2(576nm) transition.Latter of which belongs to hypersensitive transition, mainly by crystalline substance
Lattice ring border influences.Dy3+Total white light field for being emitted through CIE chromaticity coordinates figures, can effectively by near ultraviolet excitation and launch white
Light, the present invention successfully prepare single active ions and mix the fluorescent powder that single halogen mayenite matrix emits white light, which can
Light loss is reduced, reduces cost, has promoted the further development of white emitting fluorescent powder.
The present invention does not address part and is suitable for the prior art.
Claims (2)
1. a kind of mayenite structure fluorescent powder of LED white light emissions, the chemical structural formula of the fluorescent powder are as follows：
Ca12Al14O32A2: xDy3+, wherein A is one kind in Cl, F,xIt is Dy3+Substitute Ca2+Molar ratio, value range is
0.01 ≦ x ≦ 0.6。
2. a kind of preparation method of the mayenite structure fluorescent powder of the LED white light emissions described in claim 1, this method include
Following steps：
1）With CaO, Al2O3、Dy2O3、CaCl2Or CaF2For raw material, and according to Ca12Al14O32A2: xDy3+（A=Cl or F）Change
Learn metering ratio and weigh above-mentioned raw materials, raw material is uniformly mixed to be put into mortar be fully ground；
2）The raw material being fully ground is put into corundum crucible, corundum crucible is put into Muffle furnace carries out in air atmosphere
High temperature process heat, calcining heat is 1100-1200 DEG C, when calcining 12-16 is small；
3）Muffle furnace takes out corundum crucible after being cooled to room temperature, and obtained sample is fully ground, and obtains LED white lights
The mayenite structure fluorescent powder of transmitting.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110157418A (en) * | 2019-05-16 | 2019-08-23 | 浙江大学 | It is used to prepare the preparation method of the porous mayenite fluorescent material of fluorescent optical sensor |
| CN110872512A (en) * | 2018-08-30 | 2020-03-10 | 长春理工大学 | Bismuth ion activated calcium fluoroaluminate blue fluorescent powder and preparation method thereof |
| CN116333739A (en) * | 2023-03-27 | 2023-06-27 | 河北工业大学 | Activator-free matrix luminous red fluorescent powder and preparation method thereof |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101812294A (en) * | 2010-03-23 | 2010-08-25 | 东北师范大学 | White light emitting dysprosium-doped dodecacalcium heptaluminate fluorescent powder used for LED and preparation method thereof |
| CN102925145A (en) * | 2011-08-12 | 2013-02-13 | 东贝光电科技股份有限公司 | aluminate compound fluorescent powder |
| CN105219382A (en) * | 2015-10-10 | 2016-01-06 | 广西师范学院 | Eu 2+-Eu 3+codoped fluoaluminate substrate fluorescent powder and synthetic method thereof and application |
| CN107474842A (en) * | 2017-09-25 | 2017-12-15 | 江苏派诺光电科技股份有限公司 | A kind of fluorescent tube fluorescent material formula |
-
2017
- 2017-12-29 CN CN201711473787.3A patent/CN107987828A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101812294A (en) * | 2010-03-23 | 2010-08-25 | 东北师范大学 | White light emitting dysprosium-doped dodecacalcium heptaluminate fluorescent powder used for LED and preparation method thereof |
| CN102925145A (en) * | 2011-08-12 | 2013-02-13 | 东贝光电科技股份有限公司 | aluminate compound fluorescent powder |
| CN105219382A (en) * | 2015-10-10 | 2016-01-06 | 广西师范学院 | Eu 2+-Eu 3+codoped fluoaluminate substrate fluorescent powder and synthetic method thereof and application |
| CN107474842A (en) * | 2017-09-25 | 2017-12-15 | 江苏派诺光电科技股份有限公司 | A kind of fluorescent tube fluorescent material formula |
Non-Patent Citations (4)
| Title |
|---|
| HANCHENG ZHU ET AL.: "White Luminescence of Dy3+ Ions Doped 12CaO·7Al2O3 Nanopowders Under UV Light Excitation", 《JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY》 * |
| TOMOYUKI IWATA ET AL.: "Crystal structure of Ca12Al14O32Cl2 and luminescence properties of Ca12Al14O32Cl2:Eu2+", 《JOURNAL OF SOLID STATE CHEMISTRY》 * |
| WANPING CHEN ET AL.: "Synthesis and luminescence properties of blue-emitting phosphor Ca12Al14O32F2:Eu2+ for white light-emitting diode", 《LUMINESCENCE》 * |
| 祝汉成: "近紫外光激发下白光发射的镝掺杂七铝酸十二钙粉体制备及光学特性研究", 《中国优秀硕士学位论文全文数据库 基础科学辑》 * |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110872512A (en) * | 2018-08-30 | 2020-03-10 | 长春理工大学 | Bismuth ion activated calcium fluoroaluminate blue fluorescent powder and preparation method thereof |
| CN110157418A (en) * | 2019-05-16 | 2019-08-23 | 浙江大学 | It is used to prepare the preparation method of the porous mayenite fluorescent material of fluorescent optical sensor |
| CN116333739A (en) * | 2023-03-27 | 2023-06-27 | 河北工业大学 | Activator-free matrix luminous red fluorescent powder and preparation method thereof |
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Application publication date: 20180504 |