CN101376523B - Preparation of doped calcium titanate (CaTiO3: Eu3+) fluorescent powder - Google Patents

Abstract

The invention relates to a preparation method of Eu-doping calcium titanate CaTiO3:Eu<3+> fluorescent powders, which comprises the steps as follows: a soluble europium salt, a calcium salt and Ti(OC4H9)4 are weighed according to the mole ratio that is 1:49:50 to 1:4:5 among Eu<3plus>, Ca<2plus> and Ti<4plus>, and are respectively dissolved in absolute ethyl alcohol, and the confected solution is stirred for ample dissolution; (2) a mixed ethanol solution of the europium salt and the calcium salt is added in an ethanol solution of Ti(OC4H9)4, and a sol is obtained through stirring; (3) the solis placed at the temperature ranging from 0 to 50 DEG C to obtain a wet gel which is put in a baking box for drying; (4) the dried gel is milled into powders, the obtained powders are calcined for 2 to 8 hours to obtain the CaTiO3:Eu<3plus> fluorescent powders. In the preparation method, the prepared CaTiO3:Eu<3plus> fluorescent powders have high chemical durability, small grain size, pure crystalling phase and low calcination temperature; the preparation method has simple technology, and is easy for industrialized production.

Description

A kind of europium-doped calcium titanate (CaTiO 3: Eu 3+) preparation method of fluorescent material

Technical field

The invention belongs to the preparation field of fluorescent material, particularly relate to a kind of europium-doped calcium titanate (CaTiO ₃: Eu ³⁺) preparation method of fluorescent material.

Background technology

Fluorescent material as the core material of white light LEDs all is the hot research problem of lighting field all the time, and the performance of fluorescent material also directly affects the development of white light LEDs.The preparation method of fluorescent material is a lot, and main synthetic method has at present: high-temperature solid phase reaction method, sol-gel method, homogeneous coprecipitation method, low-temperature combustion synthesis, hydrothermal synthesis method, microwave radiation synthesis method, polymer-network gel method, surface diffusion method etc.Japan Ri Ya chemical company at first developed yttrium aluminum garnet with gold-tinted series, and (yttrium aluminum garnet, YAG) fluorescent material cooperated blue-ray LED to obtain high efficiency white light source in 1996.

In recent years, the scientific research personnel has carried out big quantity research to preparation, the luminescent properties of yttrium aluminum garnet series phosphor powder.This fluorescent material relies on satisfactory stability and has obtained using very widely with the matched well of corresponding led chip, and commercialization.But the design of this class blue-light LED chip collocation gold-tinted fluorescent material exists very big defective, and at first this fluorescent material is by the high-temperature solid phase reaction method preparation, although high-temperature solid phase reaction method is a synthetizing phosphor powder to be used the earliest, maximum a kind of method.But a major defect of this method be preparation temperature height, reaction not exclusively, contain a small amount of original solid material in the product.Secondly, along with the increase of duration of service, the problem of aging of chip will cause the light blue shift that sends, and the hybrid light source of the light that finally makes its and fluorescent material and sent is indigo plant partially, and colour rendering index is reduced greatly.Zhou etc. 2004 have reported a kind of Y by the wet chemistry method preparation in 93 pages of the 375th the 1st phases of volume of Alloys and Compounds. ₃Al ₅O ₁₂: RE ³⁺(RE:Eu, Dy) fluorescent material can effectively be simplified synthesis technique, but still can't solve the aging a series of problems that cause of chip.And the research of the high efficiency red fluorescent material that can effectively be excited by UV and nearly UV light can solve luminous colder this problem.The red fluorescence powder aspect, Zhuan Weidong etc. reported a kind of red fluorescence powder of divalent europium activation alkaline earth transition metal complex sulfide in 2004 854 pages of Chinese the 22nd the 6th phases of volume of rare-earth journal.Divalent europium activates sulfide (Sr, Ca) S:Eu ²⁺Excite the long 600nm of being of emission spike down at 460nm.But this fluorescent material poor stability, easy deliquescence must coat processing.As seen, still there is the problem of many sternnesses at present in the fluorescent material research field, such as, the fluorescent material that light conversion efficiency and thermal stability are good particularly can extremely be lacked by the high efficiency red fluorescent material that nearly UV light effectively excites, and extremely needs.Because the luminous efficiency of the present red fluorescent powder for white radiation LED of developing is low, can not meet the demands, this just needs us to seek new and effective red fluorescent powder for white radiation LED.

Summary of the invention

Technical problem to be solved by this invention provides a kind of CaTiO ₃: Eu ³⁺The preparation method of fluorescent material, the prepared CaTiO of the present invention ₃: Eu ³⁺Fluorescent material chemical stability height, grain-size is little, crystalline phase is pure, calcining temperature is lower.This preparation method's technology is simple, is easy to suitability for industrialized production.

A kind of europium-doped calcium titanate (CaTiO of the present invention ₃: Eu ³⁺) preparation of fluorescent material, comprising:

(1) at room temperature, press Eu ³⁺, Ca ²⁺And Ti ⁴⁺Mole ratio be that positive four butyl esters of europium salt, calcium salt and metatitanic acid that 1:49:50～1:4:5 takes by weighing solubility are dissolved in the dehydrated alcohol respectively, be mixed with the europium salt of 0.5～2mol/L, the mixed ethanol solution and the positive four butyl ester ethanolic solns of metatitanic acid of calcium salt, stir 10～60min with 50～300r/min, make abundant dissolving;

(2) the mixed ethanol solution with europium salt, calcium salt joins in the ethanolic soln of positive four butyl esters of metatitanic acid, stirs 5～15min with 50～300r/min, obtains colloidal sol;

(3) colloidal sol is placed 5～60min down at 0～50 ℃, obtain wet gel, wet gel is put into 40～120 ℃ baking oven, dry 8～48h;

(4) xerogel is worn into powder,, obtain CaTiO at 600～1500 ℃ of temperature lower calcination 2～8h ₃: Eu ³⁺Fluorescent material.

Described solubility europium salt or calcium salt preferentially use europium salt or the calcium salt nitrate Eu (NO as europium ₃) ₃6H ₂Nitrate Ca (the NO of O or calcium ₃) ₂4H ₂O.

The present invention prepares chemical stability height, grain-size is little, crystalline phase is pure, calcining temperature is low CaTiO by adopting sol-gel method ₃: Eu ³⁺Fluorescent material.Sol-gel method can be strict the control reactant between ratio, be difficult for generating the impurity phase, obtain the high reaction product of purity.With the calcium titanate is the rare earth doped chemical stability that can guarantee fluorescent material of matrix.This method process is simple, is easy to suitability for industrialized production.

Description of drawings

Fig. 1 is europium-doped calcium titanate CaTiO ₃: Eu ³⁺The X-ray diffractogram of fluorescent material;

Fig. 2 is europium-doped calcium titanate CaTiO ₃: Eu ³⁺The stereoscan photograph of fluorescent material;

Fig. 3 is europium-doped calcium titanate CaTiO ₃: Eu3 ⁺The fluorescence spectrum of fluorescent material.

Embodiment

Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiment only to be used to the present invention is described and be not used in and limit the scope of the invention.Should be understood that in addition those skilled in the art can make various changes or modifications the present invention after the content of having read the present invention's instruction, these equivalent form of values fall within the application's appended claims institute restricted portion equally.

Embodiment 1

Take by weighing 9.912g four water-calcium nitrate, 3.568g six water europium nitrates, add beaker, add the 100ml dehydrated alcohol again; Other takes by weighing positive four butyl esters of 17.000g metatitanic acid, adds beaker, adds the 100ml dehydrated alcohol again.Above-mentioned two kinds of mixtures are stirred 30min respectively form solution; The mixed ethanol solution of above-mentioned europium salt, calcium salt is added in the positive four butyl ester ethanolic solns of metatitanic acid, stirs 8min simultaneously, form colloidal sol; Colloidal sol is placed 10min under 5 ℃ of temperature, obtain wet gel, wet gel is put into 50 ℃ baking oven, dry 15h obtains xerogel; At last the presoma that obtains is calcined 2h down at 1400 ℃, promptly obtain europium-doped calcium titanate CaTiO ₃: Eu ³⁺Fluorescent material.

Fig. 1 is the X-ray diffractogram of present embodiment synthetic fluorescent material, as can be seen: diffraction peak is consistent with the diffraction peak of the calcium titanate of cube phase, discovery belongs to the diffraction peak of other oxide compound of calcium, illustrate and do not contain the impurity phase, analyse and compare by XRD data analysis software (JADE5.0), the result shows the CaTiO that has synthesized cube phase ₃: Eu ³⁺Fluorescent material.

Fig. 2 is CaTiO ₃: Eu ³⁺The stereoscan photograph of fluorescent material, this fluorescent material is better dispersed as can be seen, does not have obviously and reunites, and the powder granule particle diameter is at 50～250nm.

Fig. 3 is the fluorescence spectrum under the 400nm wavelength light of fluorescent material excites, and as can be seen: synthetic fluorescent material has higher emissive porwer under near ultraviolet excitation.

Embodiment 2

Take by weighing 9.676g four water-calcium nitrate, 4.014g six water europium nitrates, add beaker, add the 50ml dehydrated alcohol again; Other takes by weighing positive four butyl esters of 17.000g metatitanic acid, adds beaker, adds the 50ml dehydrated alcohol again.Above-mentioned two kinds of mixtures are stirred 20min respectively form solution; The mixed ethanol solution of above-mentioned europium salt, calcium salt is added in the positive four butyl ester ethanolic solns of metatitanic acid, stirs 10min simultaneously, form colloidal sol; Colloidal sol is placed 20min under 10 ℃ of temperature, obtain wet gel, wet gel is put into 120 ℃ baking oven, dry 18h obtains xerogel; At last the presoma that obtains is calcined 4h down at 1300 ℃, promptly obtain europium-doped calcium titanate CaTiO ₃: Eu ³⁺Fluorescent material.

X ray test is the result show: diffraction peak is consistent with the diffraction peak of the calcium titanate of cube phase, discovery belongs to the diffraction peak of other oxide compound of calcium, illustrate and do not contain the impurity phase that analyse and compare by XRD data analysis software (JADE5.0), the result shows the CaTiO that has synthesized cube phase ₃: Eu ³⁺Fluorescent material.

Scanning electron microscopic observation shows: this fluorescent material is better dispersed, does not have obviously and reunites, and the powder granule particle diameter is at 50～250nm.

Adopt the 400nm wavelength light to excite the fluorescence spectrum test shows of test fluorescent material: synthetic fluorescent material has higher emissive porwer under near ultraviolet excitation.

Embodiment 3

Take by weighing 9.440g four water-calcium nitrate, 4.460g six water europium nitrates, add beaker, add the 60ml dehydrated alcohol again; Other takes by weighing positive four butyl esters of 17.000g metatitanic acid, adds beaker, adds the 60ml dehydrated alcohol again.Above-mentioned two kinds of mixtures are stirred 25min respectively form solution; The mixed ethanol solution of above-mentioned europium salt, calcium salt is added in the positive four butyl ester ethanolic solns of metatitanic acid, stirs 12min simultaneously, form colloidal sol; Colloidal sol is placed 30min under 20 ℃ of temperature, obtain wet gel, wet gel is put into 80 ℃ baking oven, dry 20h obtains xerogel; At last the presoma that obtains is calcined 6h down at 1400 ℃, promptly obtain europium-doped calcium titanate CaTiO ₃: Eu ³⁺Fluorescent material.

X ray test is the result show: diffraction peak is consistent with the diffraction peak of the calcium titanate of cube phase, discovery belongs to the diffraction peak of other oxide compound of calcium, illustrate and do not contain the impurity phase that analyse and compare by XRD data analysis software (JADE5.0), the result shows the CaTiO that has synthesized cube phase ₃: Eu ³⁺Fluorescent material.

Scanning electron microscopic observation shows: this fluorescent material is better dispersed, does not have obviously and reunites, and the powder granule particle diameter is at 50～250nm.

Adopt the 400nm wavelength light to excite the fluorescence spectrum test shows of test fluorescent material: synthetic fluorescent material has higher emissive porwer under near ultraviolet excitation.

Embodiment 4

Take by weighing 11.565g four water-calcium nitrate, 0.446g six water europium nitrates, add beaker, add the 80ml dehydrated alcohol again; Other takes by weighing positive four butyl esters of 17.000g metatitanic acid, adds beaker, adds the 80ml dehydrated alcohol again.Above-mentioned two kinds of mixtures are stirred 40min respectively form solution; The mixed ethanol solution of above-mentioned europium salt, calcium salt is added in the positive four butyl ester ethanolic solns of metatitanic acid, stirs 15min simultaneously, form colloidal sol; Colloidal sol is placed 50min under 30 ℃ of temperature, obtain wet gel, wet gel is put into 100 ℃ baking oven, dry 24h obtains xerogel; At last the presoma that obtains is calcined 2h down at 1500 ℃, promptly obtain europium-doped calcium titanate CaTiO ₃: Eu ³⁺Fluorescent material.

X ray test is the result show: diffraction peak is consistent with the diffraction peak of the calcium titanate of cube phase, discovery belongs to the diffraction peak of other oxide compound of calcium, illustrate and do not contain the impurity phase that analyse and compare by XRD data analysis software (JADE5.0), the result shows the CaTiO that has synthesized cube phase ₃: Eu ³⁺Fluorescent material.

Scanning electron microscopic observation shows: this fluorescent material is better dispersed, does not have obviously and reunites, and the powder granule particle diameter is at 50～250nm.

Adopt the 400nm wavelength light to excite the fluorescence spectrum test shows of test fluorescent material: synthetic fluorescent material has higher emissive porwer under near ultraviolet excitation.

Claims (1)

1. europium-doped calcium titanate CaTiO ₃: Eu ³⁺The preparation method of fluorescent material comprises:

(1) at room temperature, press Eu ³⁺, Ca ²⁺And Ti ⁴⁺Mole ratio be that positive four butyl esters of europium salt, calcium salt and metatitanic acid that took by weighing solubility in 1: 49: 50～1: 4: 5 are dissolved in the dehydrated alcohol respectively, be mixed with the europium salt of 0.5～2mol/L, the mixed ethanol solution and the positive four butyl ester ethanolic solns of metatitanic acid of calcium salt, stir 10～60min with 50～300r/min, make abundant dissolving;

(2) the mixed ethanol solution with europium salt, calcium salt joins in the ethanolic soln of positive four butyl esters of metatitanic acid, stirs 5～15min with 50～300r/min, obtains colloidal sol;

(3) colloidal sol is placed 5～60min down at 0～50 ℃, obtain wet gel, wet gel is put into 40～120 ℃ baking oven, dry 8～48h;

(4) xerogel is worn into powder,, obtain CaTiO at 600～1500 ℃ of temperature lower calcination 2～8h ₃: Eu ³⁺Fluorescent material;

The europium salt of described solubility or calcium salt are six water europium nitrate or four water-calcium nitrates.

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