A kind of Eu
2+the silicophosphate green emitting phosphor, preparation method and the application that activate
Technical field
The present invention relates to a kind of green fluorescence luminescent material, particularly a kind of under near ultraviolet excitation the fluorescent material of transmitting green fluorescence, it can be applicable to, in ultraviolet-near ultraviolet type white light LEDs, belong to phosphor technical field.
Background technology
As natural colour display unit of future generation, light emitting diode has caused people's concern.It can be used to various electron devices, comprising instrument panel, TV (TV) and flat-panel monitor.Wherein white light LEDs (light emitting diode) is compared with traditional mains lighting supply, have energy-conservation, efficient, volume is little, the life-span is long, the advantage such as fast response time, driving voltage are low, anti-vibration, has been subject to the extensive concern in the world.
Since first white light LEDs in 1996 comes out, rapidly, luminous efficiency improves constantly, and is expected to replace traditional lighting sources such as incandescent light, luminescent lamp and high voltage mercury lamp, is called 21st century green illumination light source most with prospects in development.At present, the technology of preparing of white light LEDs mainly contains 2 kinds: (1), by three kinds of monochromatic LED combination results white lights of red, green, blue, this method can arbitrarily be adjusted color, but power supply is complicated, and cost is higher; (2) with other luminescent materials of LED de-excitation, be mixed to form white light, with blue-ray LED, coordinate the fluorescent material of Yellow light-emitting low temperature, or with three kinds of fluorescent material of near ultraviolet LED de-excitation red, green, blue.This method is no matter be to be all better than first method aspect feasibility, practicality or commercialization, so it has obtained very fast development.At two kinds, use fluorescent material to carry out in the scheme of light conversion, YAG (Y
3al
5o
12): Ce
3+yellow fluorescent powder combination, this method relative cost is lower, and efficiency is higher, but owing to lacking red composition, colour rendering index is poor.In addition, because the absorption peak of the light-converting material of blue-light LED chip requires to be positioned at 420-470nm, the fluorescent material that can meet this requirement is considerably less, absorption intensity neither be very large, find this class fluorescent material and have suitable difficulty, so the wavelength of LED chip, along with the development of manufacturing process, more and more moves toward shortwave direction, " near ultraviolet (360-410nm) type white light LEDs (NUV-LED) " become the most active system of current research.In its color quality, photochromic consistence and working process, photochromic stability aspect has more advantage.The combination of ultraviolet or near ultraviolet LED and three primary colors fluorescent powder, the method color developing is best, but fluorescent material luminous efficiency is lower at present, so development of new redness, green and blue colour fluorescent powder efficient, Heat stability is good are the keys that improves white light LEDs luminous mass.
At present, the green emitting phosphor that efficiency of conversion is higher mostly is sulfide system, this class light-emitting phosphor less stable, and light decay is large or cost is higher, and they very easily absorb deliquescence, and its poor stability can not meet the requirement of LED application.As Chinese patent CN1585141A " green fluorescent material of halide silicate green fluorescent material and pyrosilicate and orthosilicate ", this material excitation spectrum a wider range, but glow color is single and luminous intensity a little less than, can not mate with existing fluorescent material, have in actual applications significant limitation.Chinese invention patent CN101597493A " a kind of alkaline-earth metal silicophosphate fluorescent material and manufacture method and application ", chemical constitution is M
3-x-y(PO
4)
2siO
4: Eu
xr
y, 0.001≤x≤0.1 wherein, 0.001≤y≤0.2; By adding solubility promoter or add again solubility promoter in raw material after co-precipitation being processed, under high temperature reaction synthesized emission wavelength can be according to the fluorescent material of adjusting, excitation wave length and width, good chemical stability; Chinese invention patent CN101284990A " a kind of alkaline-earth metal silicophosphate white light emitting phosphor and manufacture method thereof ", the consisting of of this fluorescent material: Ba
asr
bca
c(PO
4)
x(SiO
4)
y: Eu
d, Mn
e, 3.9≤a<9 wherein, 0≤b≤3,0.1<c≤1,0.01<d≤0.1,0.01<e≤0.1,1<x≤4,0.1≤y≤2; Along with forming, change, the excitation wavelength range of this fluorescent material is ultraviolet and purple light, at 365nm, excites lower transmitting white.But by the europkium-activated Ca of the divalence of near ultraviolet excitation
15(PO
4)
2(SiO
4)
6the silicic acid calcium phosphate green emitting phosphor of structure has no open and report.
Summary of the invention
In order to overcome in prior art, luminescent phosphor luminous efficiency is low, preparation difficulty, product are impure, can not actual production utilization etc. many deficiencies, the object of the present invention is to provide a kind of chemical purity high, luminous mass is good, and simple, the eco-friendly Eu of preparation technology
2+the silicic acid calcium phosphate green emitting phosphor light powder, preparation method and the application thereof that activate.
To achieve the above object of the invention, the technical solution used in the present invention is: a kind of Eu is provided
2+the silicophosphate green emitting phosphor activating, its chemical general formula is: Ca
15-15xeu
15x(PO
4)
2(SiO
4)
6, wherein x is Eu
2+ionic replacement Ca
2+the molar fraction of ion, 0.0001 < x≤0.2.
A kind of Eu as above
2+the preparation method of the silicophosphate green emitting phosphor activating, adopts high temperature solid-state method, comprises the following steps:
(1) press chemical formula Ca
15-15xeu
15x(PO
4)
2(SiO
4)
6, wherein 0.0001 < x≤0.2, takes respectively to contain calcium ion Ca
2+compound, contain phosphonium ion P
5+compound, contain silicon ion Si
4+compound, contain europium ion Eu
3+compound, after taken various raw materials are ground respectively, mix, obtain mixture;
(2) by mixture calcining for the first time under air atmosphere, calcining temperature is 500~1000 ℃, and calcination time is 1~20 hour;
(3), after naturally cooling, grind and mix, calcining for the second time under reducing atmosphere, described reducing atmosphere is a kind of in following three kinds of atmosphere, or their combination:
the hydrogen that hydrogen atmosphere or hydrogen, nitrogen volume ratio are 0.1~0.9, nitrogen mixture body atmosphere;
be connected with the atmosphere of CO (carbon monoxide converter) gas;
the gas atmosphere that carbon granules or gac are produced at combustion synthesis in air;
Calcining temperature is 800~1350 ℃, and calcination time is 3~10 hours, obtains a kind of Eu
2+the silicic acid phosphate green emitting phosphor activating.
A preferred version provided by the invention is: calcining temperature is 650~1000 ℃ for the first time, and calcination time is 5~9 hours; Calcining temperature is 950~1350 ℃ for the second time, and calcination time is 3~9 hours.
A kind of Eu as above
2+the preparation method of the silicophosphate green emitting phosphor activating, the present invention also provides a kind of employing chemical solution method, comprises the following steps:
(1) to contain calcium ion Ca
2+compound, contain phosphonium ion P
5+compound, contain silicon ion Si
4+compound, contain europium ion Eu
3+compound be raw material, by general formula Ca
15-15xeu
15x(PO
4)
2(SiO
4)
6the stoichiometric ratio of middle corresponding element takes each raw material, wherein 0.0001 < x≤0.2; The raw material taking is dissolved in respectively in nitric acid and with deionized water and is diluted, then add respectively complexing agent by 0.5~2.0wt% of reactant quality in each raw material, obtain the mixed solution of each raw material; Described complexing agent is a kind of in citric acid, oxalic acid, or their combination;
(2) mixed solution of each raw material slowly being mixed, is to stir 1~2 hour under the condition of 50~100 ℃ in temperature, standing, obtain fluffy presoma after drying;
(3) by presoma calcining for the first time in air atmosphere, calcining temperature is 300~500 ℃, and calcination time is 1~8 hour;
(4), after naturally cooling, grind and mix, calcining for the second time in air atmosphere, calcining temperature is 500~900 ℃, calcination time is 1~9 hour;
(5) after naturally cooling, grind and mix, under reducing atmosphere, calcine, described reducing atmosphere is a kind of in following three kinds of atmosphere, or their combination:
the hydrogen that hydrogen atmosphere or hydrogen, nitrogen volume ratio are 0.1~0.9, nitrogen mixture body atmosphere;
be connected with the atmosphere of CO (carbon monoxide converter) gas;
the gas atmosphere that carbon granules or gac are produced at combustion synthesis in air;
Calcining temperature is 700~1300 ℃, and calcination time is 2~8 hours, obtains a kind of silicic acid phosphate green emitting phosphor.
The compound that contains calcium ion of the present invention is: a kind of or their combination in calcium oxide, nitrocalcite, calcium carbonate; The described compound that contains positively charged ion silicon is a kind of in silicic acid, tetraethoxy or their combination; The compound that contains phosphorus is a kind of in Vanadium Pentoxide in FLAKES, primary ammonium phosphate, ammonium hydrogen phosphate, ammonium phosphate or their combination; The compound that contains europium ion is a kind of in europium sesquioxide, europium nitrate or their combination.
A preferred version provided by the invention is: described calcining temperature is for the first time 400~500 ℃, and calcination time is 5~8 hours; Calcining temperature is 700~900 ℃ for the second time, and calcination time is 6~9 hours; Third firing temperature is 1000~1300 ℃, and calcination time is 5~8 hours
A kind of Eu as above
2+the silicic acid calcium phosphate green emitting phosphor activating, is applied to illumination or the display device of the white light emitting diode of near ultraviolet excitation.
Compared with prior art, the advantage of technical solution of the present invention is:
1, silicic acid calcium phosphate matrix provided by the invention, is easy to realize the filling of bivalent rare earth europium ion in this matrix, and can make rare-earth cation stable existence in matrix.
2, this green emitting phosphor can be excited by near ultraviolet light well, can well be applied near ultraviolet type white light LEDs (NUV-LED) device.
3, the fluorescent material making has good luminous intensity, stability, color developing and granularity, is conducive to realize the high-power LED of preparation.
4, the preparation process of substrate material of the present invention is simple, product easily collecting, and without waste water and gas discharge, environmental friendliness, is especially applicable to serialization and produces.
Accompanying drawing explanation
Fig. 1 is the X-ray powder diffraction collection of illustrative plates of sample and the contrast of standard card PDF#50-0905 of preparing by the technology of the embodiment of the present invention 1;
Fig. 2 is the sample prepared by the technology of the present invention solid reaction process luminescent spectrum under near-ultraviolet ray 400 nanometers excite;
Fig. 3 is the ultraviolet that obtains of material sample monitoring utilizing emitted light 500 nanometers prepared by the technology of the present invention and the exciting light spectrogram of near ultraviolet region;
Fig. 4 prepares the luminescent spectrum of sample under near-ultraviolet ray 390 nanometers excite by the technology of the present invention chemical synthesis;
Fig. 5 is that in embodiment, excitation wavelength is 355 nanometers, and detecting wavelength is the decay of luminescence curve of 500 nanometers.
Embodiment
Below in conjunction with drawings and Examples, the invention will be further described.
Embodiment 1:
Preparation Ca
14.25eu
0.75(PO
4)
2(SiO
4)
6
According to chemical formula Ca
14.25eu
0.75(PO
4)
2(SiO
4)
6in the stoichiometric ratio of each element take respectively calcium carbonate CaCO
3: 2.853 grams, europium sesquioxide Eu
2o
3: 0.264 gram, primary ammonium phosphate NH
4h
2pO
4: 0.461 gram, silicon-dioxide SiO
2: 0.721 gram, after grinding in agate mortar and mixing, select air atmosphere to calcine for the first time, temperature is 900 ℃, calcination time 7 hours, is then cooled to room temperature, takes out sample.By the raw material of calcining for the first time, fully mixed grinding is even again, among the reducing atmospheres such as nitrogen (interpolation gac), CO (carbon monoxide converter) gas, hydrogen or nitrogen and hydrogen mixture, carry out sintering again, 1320 ℃ of temperature, calcination time 8 hours, then be chilled to room temperature, take out sample.Obtain the rare earth doped divalent europium Eu of powder shaped
2+phosphorus Calucium Silicate powder green luminescent material.
Referring to accompanying drawing 1, it is the X-ray powder diffraction collection of illustrative plates of material sample and the comparison of standard card PDF#50-0905 of preparing by the present embodiment technical scheme, the demonstration of XRD test result, and prepared material is phosphorus Calucium Silicate powder Ca
15(PO
4)
2(SiO
4)
6monophase materials.
Referring to accompanying drawing 2, it is 5% concentration Eu
2+ion is at Ca
14.25eu
0.75(PO
4)
2(SiO
4)
6in fluorescent material, with near-ultraviolet light 400nm, excite the luminescent spectrum obtaining, the green emitting wave band that the main center emission wavelength of this material is about 500nm, by CIE, calculate simultaneously, the coordinate of learning it is x=0.135, y=0.562, also just in time drop on green area, it can finely be applicable to the white light LEDs that near-ultraviolet light is excitation light source.
Referring to accompanying drawing 3, what from the material sample monitoring utilizing emitted light 500nm to preparing by the technology of the present invention, obtain can find out the exciting light spectrogram of near ultraviolet region, the green emitting of this material excite the mainly near ultraviolet between 330 ~ 420 nm (NUV) region, source, can mate well near ultraviolet LED chip.
Referring to accompanying drawing 5, it is that the material sample of preparing by the present embodiment technical scheme is 355 nanometers in excitation wavelength, and detecting wavelength is the decay of luminescence curve of 500 nanometers, and be 1600 nanoseconds the fall time that can calculate this green emitting phosphor from figure.
Embodiment 2:
Preparation Ca
14.25eu
0.75(PO
4)
2(SiO
4)
6
According to chemical formula Ca
14.25eu
0.75(PO
4)
2(SiO
4)
6in the stoichiometric ratio of each element take respectively calcium oxide CaO:3.996 gram, europium nitrate Eu (NO
3)
3: 1.268 grams, Vanadium Pentoxide in FLAKES P
2o
5: 0.710 gram, silicon-dioxide SiO
2: 1.803 grams, after grinding in agate mortar and mixing, select air atmosphere to calcine for the first time, temperature is 950 ℃, calcination time 6 hours, is then cooled to room temperature, takes out sample.By the raw material of calcining for the first time, fully mixed grinding is even again, among the reducing atmospheres such as nitrogen (interpolation gac), CO (carbon monoxide converter) gas, hydrogen or nitrogen and hydrogen mixture, carry out sintering again, 1300 ℃ of temperature, calcination time 8 hours, then be chilled to room temperature, take out sample.Obtain the rare earth doped divalent europium Eu of powder shaped
2+phosphorus Calucium Silicate powder green luminescent material.Its main structure properties, excitation spectrum, luminescent spectrum and extinction curve are similar to embodiment 1.
Embodiment 3:
Preparation Ca
13.5eu
1.5(PO
4)
2(SiO
4)
6
According to chemical formula Ca
13.5eu
1.5(PO
4)
2(SiO
4)
6in the stoichiometric ratio of each element take respectively calcium carbonate CaCO
3: 2.703 grams, europium nitrate Eu (NO
3)
3: 1.014 grams, primary ammonium phosphate NH
4h
2pO
4: 0.461 gram, silicon-dioxide SiO
2: 0.721 gram, after grinding in agate mortar and mixing, select air atmosphere to calcine for the first time, temperature is 850 ℃, calcination time 8 hours, is then cooled to room temperature, takes out sample.By the raw material of calcining for the first time, fully mixed grinding is even again, among the reducing atmospheres such as nitrogen (interpolation gac), CO (carbon monoxide converter) gas, hydrogen or nitrogen and hydrogen mixture, carry out sintering again, 1350 ℃ of temperature, calcination time 7 hours, then be chilled to room temperature, take out sample.Obtain the rare earth doped divalent europium Eu of powder shaped
2+phosphorus Calucium Silicate powder green luminescent material.Its main structure properties, excitation spectrum, luminescent spectrum and extinction curve are similar to embodiment 1.
Embodiment 4:
Preparation Ca
13.5e
1.5(PO
4)
2(SiO
4)
6
According to chemical formula Ca
13.5eu
1.5(PO
4)
2(SiO
4)
6in the stoichiometric ratio of each element take respectively nitrocalcite Ca (NO
3)
2: 4.431 grams, europium sesquioxide Eu
2o
3: 0.528 gram, ammonium phosphate (NH
4)
3pO
4: 0.597 gram, silicon-dioxide SiO
2: 0.721 gram, after grinding in agate mortar and mixing, select air atmosphere to calcine for the first time, temperature is 1000 ℃, calcination time 5 hours, is then cooled to room temperature, takes out sample.By the raw material of calcining for the first time, fully mixed grinding is even again, among the reducing atmospheres such as nitrogen (interpolation gac), CO (carbon monoxide converter) gas, hydrogen or nitrogen and hydrogen mixture, carry out sintering again, 1350 ℃ of temperature, calcination time 7 hours, then be chilled to room temperature, take out sample.Obtain the rare earth doped divalent europium Eu of powder shaped
2+phosphorus Calucium Silicate powder green luminescent material.Its main structure properties, excitation spectrum, luminescent spectrum and extinction curve are similar to embodiment 1.
Embodiment 5:
Preparation Ca
14.25eu
0.75(PO
4)
2(SiO
4)
6
According to chemical formula Ca
14.25eu
0.75(PO
4)
2(SiO
4)
6in the stoichiometric ratio of each element, take respectively nitrocalcite Ca (NO
3)
2 .4H
2o:3.365 gram, europium sesquioxide Eu
2o
3: 0.132 gram, primary ammonium phosphate NH
4h
2pO
4: 0.230 gram, tetraethoxy Si (OC
2h
5)
4: 1.250 grams, then take the citric acid of the 0.5wt% of above medicine total mass; First by the Si (OC taking
2h
5)
4by deionized water, ethanol, nitric acid heated and stirred, dissolve (controlling pH=2), then add appropriate citric acid to stir 2 hours; Then by the Eu taking
2o
3with appropriate deionized water, nitric acid and citric acid post-heating to 50 ℃, carry out stir process; Above-mentioned two kinds of solution are mixed, then add therein Ca (NO
3)
2 .4H
2o, NH
4h
2pO
4heated and stirred, and add several times appropriate amount of deionized water and nitric acid, continue to stir 2 hours, standing, dry, obtain fluffy presoma; Calcining temperature is 450 ℃ for the first time, calcination time 6 hours; Calcining temperature is 900 ℃ for the second time, calcination time 7 hours; Third firing temperature is 1250 ℃, and calcination time 8 hours obtains the rare earth doped divalent europium Eu of powder shaped
2+phosphorus Calucium Silicate powder green luminescent material.Its main structure properties, excitation spectrum, luminescent spectrum and extinction curve are similar to embodiment 1.Fig. 4 is its utilizing emitted light spectrogram under 390nm excites, and can lead to the same conclusion, and just intensity changes to some extent.This has well verified, this green emitting phosphor can be excited by the good multi-wavelength of near ultraviolet region.
Embodiment 6:
Preparation Ca
13.5eu
1.5(PO
4)
2(SiO
4)
6
According to chemical formula Ca
13.5eu
1.5(PO
4)
2(SiO
4)
6in the stoichiometric ratio of each element, take respectively calcium carbonate CaCO
3: 2.703 grams, europium nitrate Eu (NO
3)
3: 1.014 grams, primary ammonium phosphate NH
4h
2pO
4: 0.460 gram, tetraethoxy Si (OC
2h
5)
4: 2.500 grams, then take the citric acid of the 0.5wt% of above medicine total mass; First by the Si (OC taking
2h
5)
4by deionized water, ethanol, nitric acid heated and stirred, dissolve (controlling pH=2), then add appropriate citric acid to stir 2 hours; Then by the CaCO taking
3with appropriate deionized water, nitric acid and citric acid post-heating to 50 ℃, carry out stir process; Above-mentioned two kinds of solution are mixed, then add therein Eu (NO
3)
3, NH
4h
2pO
4heated and stirred, and add several times appropriate amount of deionized water and nitric acid, continue to stir 2 hours, standing, dry, obtain fluffy presoma; Calcining temperature is 500 ℃ for the first time, calcination time 5 hours; Calcining temperature is 850 ℃ for the second time, calcination time 9 hours; Third firing temperature is 1300 ℃, and calcination time 7 hours obtains the rare earth doped divalent europium Eu of powder shaped
2+phosphorus Calucium Silicate powder green luminescent material.Its main structure properties, excitation spectrum, luminescent spectrum and extinction curve are similar to embodiment 1.