CN105670624B - One kind is based on blue light white light conversion phosphor and preparation method thereof under burst of ultraviolel - Google Patents

Abstract

One kind is based on blue light white light conversion phosphor and preparation method thereof under burst of ultraviolel, and the chemical formula of the fluorescent material is Sr_1‑n(WO₄)_1‑xCl_2x:NEu fluorescent material is single-phase luminescent material, with WO₄ ^2‑、Eu²⁺And Eu³⁺Three centres of luminescence, n, X are molal quantity, 0 ＜ X ＜ 0.03,0.03≤n≤0.15.The single-component phosphor of the present invention, can send blue light and white light under different wave length ultraviolet excitation；And white light, the blue light sent out are respectively provided with good stability and luminescence feature.

Description

One kind is based on blue light-white light conversion phosphor and preparation method thereof under burst of ultraviolel

Technical field

The present invention relates to luminescent material technical field, and in particular to a kind of blue light-white light conversion phosphor and its preparation side Method.

Background technology

Tungstates is as a kind of stable luminescent property, with excellent excitation and the self-activation phosphor for stablizing chemical property Material, is constantly subjected to the extensive concern of domestic and international researcher.It is increasingly mature with White light LED technology, find best in quality glimmering Light powder becomes more and more important, using tungstates as matrix, and rare earth ion becomes research naturally for the fluorescent material of the centre of luminescence Emphasis.In order to study the property using strontium tungstate as the luminescent material of matrix, the research of history is concentrated mainly on three aspects.First It is the property of strontium tungstate in itself, the growth mechanism and optical characteristics of such as glitter, crystal, vibrational spectrum and thermal property and synthesis Control etc., this kind of research lays a solid foundation for the stability study of matrix.Second aspect is cation doping, i.e., strontium from Subdivision by other ionic compartmentations such as Ca, to obtain more reasonable structure, the centre of luminescence is helped bigger or carries out photocontrol Optimize matrix.Certainly, the luminosity of fluorescent material mainly determines that the centre of luminescence determines material emission by its centre of luminescence Color, brightness, purity etc., rare-earth cation has a 4f5d electron configurations by external world's shielding of underfill, and 4f electronics can be with Within f-f configurations or transition between f-d configurations, with abundant electron energy level and long-life excitation state, it can launch from purple The light wave of the outer various wavelength to infrared light district, therefore, the research using rare-earth cation as the centre of luminescence becomes all researchs Widest form in aspect.Eu³⁺It is luminous to be concentrated mainly on region of red light, it is a variety of many because being received the need for white light LEDs The research of sample, such as synthesized with molten-salt growth method, ethylene glycol, microwave method, solid phase method, sol-gel process etc. to powder.In addition, with tungsten Sour strontium is matrix, with Tm³⁺、Yb³⁺、Pr³⁺、Tb³⁺、Nd³⁺、Sm³⁺Plasma is also studied for the luminescent material of the centre of luminescence.

The content of the invention

It is an object of the invention to provide a kind of single-component phosphor, blue light can be sent under different wave length ultraviolet excitation And white light；And white light, the blue light sent out are respectively provided with good stability and luminescence feature.

Another object of the present invention aims to provide the preparation method of above-mentioned fluorescent material.

One kind of the present invention is based on blue light-white light conversion phosphor under burst of ultraviolel, and its chemical formula is Sr_1-n(WO₄)_{1- x}Cl_2x:NEu fluorescent material is single-phase luminescent material, with WO₄ ^2-、Eu²⁺And Eu³⁺Three centres of luminescence, n, X are molal quantity, 0 ＜ X ＜ 0.03,0.03≤n≤0.15.

The present invention preferably 0.01≤X ＜ 0.03.The preferred scheme of the present invention also includes 0.01≤X≤0.02.

The present invention preferably 0.05≤n≤0.1.

The present invention based on blue light under burst of ultraviolel-white light conversion phosphor, be the ultraviolet excitation in 240~260nm Under, fluorescent material blue light-emitting；Fluorescent material emits white light under 266~300nm ultraviolet excitation.Preferred implementation process is Under 250nm ultraviolet excitation, fluorescent material blue light-emitting；Fluorescent material emits white light under 294 ultraviolet excitation.

The preparation method based on blue white light-white light conversion phosphor under burst of ultraviolel of the present invention, described fluorescent material is The raw material for preparing fluorescent material is synthesized by high temperature solid state reaction in air atmosphere；Described high temperature is 800 DEG C~950 DEG C.

Described phosphor raw material is：Strontium carbonate, ammonium metatungstate, ammonium chloride and europium oxide, by generation Sr_1-n(WO₄)_{1- x}Cl_2x:Stoichiometric proportion needed for nEu prepares grinding, high temperature solid state reaction synthesis.

The currently preferred high temperature solid state reaction time is 1~4 hour.

Advantages of the present invention and effect are：The Sr of the present invention_1-n(WO₄)_1-xCl_2x:NEu fluorescent material is single-phase luminous material Material, particle is uniform, and the luminescent material has WO₄ ^2-、Eu²⁺、Eu³⁺Three centres of luminescence, work as Cl^-When concentration is relatively low, three centres of luminescence Light simultaneously, in blueness under 250nm burst of ultraviolel, fluorescent material is with Cl^-The increase of concentration is close from blue light to white light field, color Wen Gao；White light best in quality is sent in the case where 294nm is excited；When x is between 0.01 and 0.03, the fluorescent material of body series has Good blue light and white-light emitting effect, when particularly between 0.01 and 0.02, can maintain optimal blue light and white light Illumination effect；As x >=0.03, Eu³⁺Ion concentration is not enough to show its emission spectrum.System has three centres of luminescence, point It is not WO42-, Eu²⁺And Eu³⁺, with outstanding luminescent quality, can as specific use blue emitting phosphor, can also be single Solely as the potential substitute of white light LEDs.

The advantage of the preparation method of the present invention is, Sr has been synthesized using high temperature solid-state method_1-n(WO₄)_1-xCl_2x:NEu fluorescence Powder, is single-phase luminescent material.Cl^-Addition by part Eu³⁺It is reduced to Eu²⁺, production process is completed in air atmosphere, without adding Enter protective gas reducing gas or other reducing agents.Resulting fluorescent powder grain is uniform, reunites without a large amount of powder Phenomenon.

Brief description of the drawings

Fig. 1 is the Sr of Solid phase synthesis_0.95(WO₄)_1-xCl_2x:0.05Eu XRD.

Fig. 2 is N3 samples Sr_0.95(WO₄)_0.98Cl_0.04:0.05Eu SEM figures.

Fig. 3 is the excitation and emission spectra figure of N2 samples.

Fig. 4 is different Cl^-The excitation spectrum and launching light spectrogram of content.Wherein (a) is the exciting light that 397nm monitors wavelength Spectrum, (b) is the emission spectrum Waterfall plot of 250nm excitation wavelengths, and (c) is the excitation spectrum that 616nm monitors wavelength, and (d) is 294nm The emission spectrum Waterfall plot for the series of samples that wavelength is excited.

Fig. 5 is N5 and N6 emission spectrum (λ_ex=281nm) figure.

The Sr of Fig. 6 present invention_1-n(WO₄)_1-xCl_2x:NEu chromatic diagram：(a)λ_ex=250nm (b) λ_ex=294nm.

Embodiment

Following examples are intended to illustrate invention, rather than limitation of the invention further.

Comparative example 1, embodiment 1-5

By Sr_0.95(WO₄)_1-x Cl_2x:0.05Eu stoichiometric proportions weigh strontium carbonate (SrCO₃), ammonium metatungstate (NH₄)₆H₂W₁₂O₄₀·nH₂O (molecular weight：2956.26), ammonium chloride (NH₄Cl) (being that analysis is pure above) and europium oxide (Eu₂O₃) (99.99%), wherein x values are followed successively by 0,0.01,0.02,0.03,0.04 and 0.05, and the sample correspondence for obtaining comparative example 1 is compiled Number it is designated as N1, embodiment 1-5 sample N2, N3, N4, N5, N6.Assay balance is used in weighing for material, and its precision is 0.1 milligram. Load weighted raw material are respectively placed in by number and is fully ground 1.5h in different agate mortars and is well mixed it, then will Ground raw material are put into corundum crucible, the lower 900 DEG C of roastings 3h of air atmosphere in high temperature resistance furnace.High temperature resistance furnace temperature Program is set to：200 DEG C/30min to 800 DEG C, then 100 DEG C/30min to 900 DEG C.Furnace cooling is to room after the completion of sample sintering Temperature produces material requested.

The N1-N6 tests of sample are with characterizing

Powder x-ray diffraction analysis are carried out to the powder sintered with DMAX-2500 types X-ray diffractometer (XRD).Test Parameter is：Cu (K α) target, tube voltage 40Kv, tube current 250mA, 5-80 ° of scanning range.0.02 ° of scanning step, sweep speed is 10°/min。

The environment of Quanta 200 that the information analyses such as pattern, particle size, the dispersiveness of powder are produced in FEI Co. of the U.S. Carried out in SEM (ESEM).

Spectrofluorimetry uses the excitation spectrum of fluorescent material prepared by Hitachi F-4500 type fluorescence spectrophotometer measurements And emission spectrum.Test condition is：Xenon lamp lamp source, slit width 10nm, voltage 400V, sweep speed 240nm/min.

As a result with discussion

1st, structural analysis

Fig. 1 is the Sr of Solid phase synthesis_0.95(WO₄)_1-xCl_2x:0.05Eu XRD.Fig. 1 (a) be N3 samples (on) with Standard PDF cards (under) (card number：PDF#85-0587 compares figure), it can be seen that the spectral line of N3 samples and card Fit like a glove, any miscellaneous peak phase do not occur.Fig. 1 (b) be N1-N6 samples XRD, the intensity and peak position of all spectral lines with Standard spectrum is basically identical, it is seen that Cl^-And Eu²⁺/Eu³⁺Doping to SrWO₄Crystal structure influence is little, and the sample crystal formation of preparation is good Good, thing is mutually single.The most strong diffraction maximum of series of samples is 27.5 or so, corresponding to SrWO₄(112) crystal face, illustrate synthesis Sample be tetragonal crystal system scheelite-type structure.

Fig. 2 is N3 samples Sr_0.95(WO₄)_0.98Cl_0.04:0.05Eu SEM figures.Fig. 2 (a) is the effect after 2500 times of amplification Fruit is schemed, and the particle that solid phase method sinters (a) has reunion, but size is substantially uniform, is mutually produced without obvious second, is tied with XRD Fruit is consistent.Fig. 2 (b) is 10,000 times of design sketch of amplification, the SrWO obtained with L.S.Cavalcante etc. with ion implantation₄It is micro- Brilliant high magnification FESEM figures are basically identical.It can be seen that powder particle spherical in shape, size is about 2um, after reunion Powder is in petal-shaped, is extended from the inside to the outside.

2nd, excitation spectrum and emission spectrum

Fig. 3 is the excitation and emission spectra figure of N2 samples.It monitors wavelength for 397nm to Fig. 3 (a) excitation spectrum, swashs Hair spectrum is unique wideband spectrum, and its peak value, in 250nm or so, is Eu²⁺And Eu³⁺PLE；Under ultraviolet the exciting of 250nm, Emission spectrum is the broadband emission from 350nm to 600nm, includes Eu²⁺Characteristic emission and tungstate radicle broadband emission, additionally There are several obvious Eu³⁺The spectral line of emission, 469nm, 590nm, 616nm emission spectra corresponds to Eu respectively³⁺'s⁵D₂→⁷F₀,⁵D₀→⁷F₁,⁵D₀→⁷F₂Transition, but its emissive porwer all very littles.Fig. 3 (b) is the emission spectrum under 294nm is excited, mainly by one section of 350nm Wire transmitting to 550nm broadband emission and 616nm is constituted.Broadband emission shape very irregular because the section transmitting by Three parts are constituted, and wherein peak value corresponds to Eu in 410nm or so broadband emission²⁺Characteristic emission, transmitting of the peak value in 469nm It is Eu³⁺'s⁵D₂→⁷F₀Transition is launched, and this two parts emission spectra is entrained in the broadband emission of whole tungstate radicle.Fig. 3 (b) is left The upper excitation spectrum monitored for 616nm under wavelength, excited by 294nm broadband excitation, 397nm and 469nm wire and The parts of strong absorption band three of 350nm backward are constituted.294nm broadband emission belongs to Eu²⁺/Eu³⁺Ground state arrives charge transfer state Absorptive transition, corresponding to O^2-→Eu²⁺/Eu³⁺And O^2-→W⁶⁺Charge transfer band excite.Two lines shape PLE corresponds to Eu³⁺'s⁷F₀→⁵L₆(397nm) and⁷F₀→⁵D₂(469nm) transition.If system does not introduce Cl-, the SrWO of Eu3+ doping₄System 350nm does not have excitation band backward, so, this section of excitation band is probably because Cl^-After doping, part Eu³⁺Electric charge is excited to move State is moved, electric charge is from Cl^-3p be transferred to Eu³⁺4f, Eu³⁺It is reduced to Eu²⁺。Eu²⁺Ground state level be 4f⁷, lowest excited state May be by 4f⁷Or 4f⁶5d is formed, and works as 4f⁶With 5d electron interactions it is stronger when, energy level severity of mixing up strengthen, produce excitation band.

3、Cl^-Influence of the concentration to material emission performance

Different Cl^-Content, matrix and the centre of luminescence are different by being influenceed, then excitation spectrum and emission spectrum have very Big change.Fig. 4 is different Cl^-The excitation spectrum and launching light spectrogram of content.Fig. 4 (a) is the exciting light that 397nm monitors wavelength Spectrum, is doped into a small amount of Cl^-Afterwards, the excitation spectrum of N2, N3 sample is composed for 250nm broadband excitation, by Eu²⁺And Eu³⁺Excite Spectrum is collectively formed, Eu²⁺And Eu³⁺Material total amount it is constant, therefore this section excites the spectral intensity not with Cl^-The change of content and change Become.With Cl^-Occurs second segment broadband excitation spectrum at the increase of content, 281nm, this section of wideband spectrum is main by O^2-→Eu²⁺With And O^2-→W⁶⁺Charge transfer band is formed, Cl^-The increase of content exacerbates Eu³⁺Charge transfer state increases, Eu²⁺Content increases, because This this section of exciting line intensity Cl^-The increase of content and become strong.3rd section of broadband spectrum peak is located at 326nm, the Eu belonged to²⁺Allusion quotation Type is excited.Fig. 4 (b) is the emission spectrum Waterfall plot of 250nm excitation wavelengths, and whole emission spectrum is considered as a broadband excitation Compose, 397nm or so emissive porwer is by Eu²⁺D-f transition and Eu³⁺F-f transition joint contributions, so intensity is basically unchanged； The broadband emission of remainder is contributed by tungstate radicle；Although spectral line of emission relative intensity of the N2 and N3 samples at 616nm compared with It is low but still visible, (N3), Eu as x=0.03³⁺616nm characteristic spectral lines disappear, illustrate Eu³⁺Concentration be not enough to hair Penetrate the energy that can be sensed by detector.

Fig. 4 (c) is the excitation spectrum that 616nm monitors wavelength, and the excitation spectrum of N2 and N3 samples is main by Eu³⁺O^2- →Eu³⁺And O^2-→W⁶⁺Charge transfer band (294nm),⁷F₀→⁵L₆(397nm) and⁷F₀→⁵D₂(469nm) transition is constituted, and illustrates x= Eu when 0.02³⁺Concentration it is still very high.No longer there is obvious Eu in the excitation spectrum of N4, N5 and N6 sample³⁺PLE Line, illustrates Eu³⁺Charge transfer state is largely excited to, is reduced to Eu²⁺.Fig. 4 (d) is the serial sample that 294nm wavelength is excited The emission spectrum Waterfall plot of product, 294nm is O^2-→Eu²⁺/Eu³⁺And O^2-→W⁶⁺Charge transfer band, the Eu under 294nm exciting^{2 +}And Eu³⁺The emission spectrum of itself can be launched.Cl is can clearly be seen that from figure^-The increase of content launches light to system The influence of spectrum, it is tungstate ion and Eu that N2 samples are luminous³⁺The coefficient result of emission spectrum；N3 samples are attached in 400nm Emission peak closely is occurred in that, this is Eu²⁺The collective effect of emission spectrum and tungstate ion emission spectrum, Eu³⁺Emission spectrum it is strong Degree is still very big；N4 samples can as whole process turnover, Eu³⁺Disappeared in 616nm characteristic peak, Eu²⁺It is attached in 400nm Near emission peak occurs；Hereafter the emission spectrum of N5 with N6 samples is similar, without Eu³⁺Characteristic peak, illustrate to work as x=0.04 When, Eu³⁺Major part is reduced to Eu²⁺。

Fig. 5 is emission spectrum of the N5 and N6 samples in the case where 281nm wavelength is excited, corresponding to λ in Fig. 4 (a)_em=397nm Excite.It can be seen that in the case where 281nm wavelength is excited, the emission spectrum of N5 and N6 samples is main by Eu²⁺Feature Spectral line is constituted, the transmitting for secondly also having the relatively low tungstate ion of relative intensity, Cl^-Concentration does not have too much influence to system.

4、Sr_1-n(WO₄)_1-xCl_2x:nEu²⁺/Eu³⁺Illumination effect

Table 1 is the different Cl calculated using CIE1931 chromaticity coordinates software for calculation^-Content Sr under different excitation wavelengths_1-n (WO₄)_1-xCl_2x:nEu²⁺/Eu³⁺The chromaticity coordinates of luminescent material.W1 values are 250nm in table, and W2 values are 294nm.With Cl^-Content increases Plus, the chromaticity coordinates X for the series of samples that 250nm is excited, Y value gradually increase, and colour temperature is gradually reduced, and corresponding dominant wavelength is substantially not Become；Chromaticity coordinates X, Y of sample under 294nm is excited first increases, and since N4 samples, coordinate values reduce suddenly, behind N5, N6 numerical value slowly diminishes, and colour temperature is then in contrast, and N3 reduces than N2, and N4 increases suddenly, behind N5, N6 significantly raise, In N2, N3 phase change less, the later stage persistently reduces dominant wavelength.

The chromaticity coordinates of table 1, colour temperature and correspondence dominant wavelength

CIE chromaticity coordinates(x,y)at different excitation wavelength

Fig. 6 is the chromatic diagram drawn according to chromaticity coordinates.Under ultraviolet the exciting of 250nm, series of samples is luminous by blue region Domain is close to white portion；Under 294nm burst of ultraviolel, series of samples first turns to green area by white portion, then to indigo plant Color region is close.This is primarily due to work as Cl^-When concentration is smaller, sample it is luminous by WO₄ ^2-、Eu²⁺And Eu³⁺It is common to complete, with Cl^-The increase of concentration, as x >=0.03, the luminous mainly WO of sample₄ ^2-And Eu²⁺Tuning result.Knowable to comparison sheet 1, when Cl^-When concentration is relatively low, blue light wave of the centre wavelength 477 or so, but its colour temperature can be obtained under ultraviolet the exciting of 250nm Height, available for the place higher to cool colour demand, other fluorescent material that also can be relatively low with colour temperature are arranged in pairs or groups, to obtain white light Chromaticity requirements required for LED；The white light that colour temperature is moderate, illumination effect is good can be then obtained under 294nm ultraviolet exciting, no Need to be allocated with other fluorescent material, this exactly white light LEDs in terms of illumination, display lamp required for result.

4 conclusions

Sr (WO have been synthesized using high temperature solid-state method₄)_1-xCl_2x:Eu²⁺/Eu³⁺Luminescent material.XRD tests show the fluorescent material It is still single-phase crystal in x=0.05, FESEM shows that its exterior appearance is in uniform spheric granules, and diameter is about 2um. Under 250nm burst of ultraviolel, fluorescent material is with Cl^-The increase of concentration is close from blue light to white light field, and colour temperature is high；294nm's Under burst of ultraviolel, fluorescent material is with Cl^-The increase of concentration is close to blue region from the good white light of chromaticity matter.Chromaticity coordinates and colourity Figure is shown, when x is between 0.01 and 0.02, and the fluorescent material of body series has optimal blue light and white-light emitting effect, when x >= When 0.03, Eu³⁺Ion concentration is not enough to show its emission spectrum.System has three centres of luminescence, is WO42-, Eu respectively²⁺ And Eu³⁺, with outstanding luminescent quality, can as specific use blue emitting phosphor, can also be separately as white light LEDs Potential substitute.

Claims (9)

1. one kind is based on blue light-white light conversion phosphor under burst of ultraviolel, it is characterised in that chemical formula is Sr_1-n(WO₄)_{1- x}Cl_2x:NEu fluorescent material is single-phase luminescent material, with WO₄ ^2-、Eu²⁺And Eu³⁺Three centres of luminescence, n, x are molal quantity, 0 ＜ X ＜ 0.03,0.03≤n≤0.15.

2. according to claim 1 be based on blue light-white light conversion phosphor under burst of ultraviolel, it is characterised in that 0.01≤x ＜ 0.03.

3. according to claim 2 be based on blue light-white light conversion phosphor under burst of ultraviolel, it is characterised in that 0.01≤x ≤0.02。

4. according to claim 1 be based on blue light-white light conversion phosphor under burst of ultraviolel, it is characterised in that 0.05≤n ≤0.1。

5. according to claim 1 or 2 or 3 or 4 based on blue light under burst of ultraviolel-white light conversion phosphor, its feature exists In, under 240~260nm ultraviolet excitation, fluorescent material blue light-emitting；Fluorescent material is sent out under 266~300nm ultraviolet excitation White light.

6. according to claim 5 be based on blue light-white light conversion phosphor under burst of ultraviolel, it is characterised in that in 250nm Ultraviolet excitation under, fluorescent material blue light-emitting；Fluorescent material emits white light under 294 ultraviolet excitation.

7. the preparation method based on blue light under burst of ultraviolel-white light conversion phosphor described in claim any one of 1-6, described Fluorescent material be to synthesize the raw material for preparing fluorescent material by high temperature solid state reaction in air atmosphere；Described high temperature is 800 DEG C~950 DEG C.

8. the preparation method according to claim 7 based on blue light under burst of ultraviolel-white light conversion phosphor, described is glimmering Light powder raw material is：Strontium carbonate, ammonium metatungstate, ammonium chloride and europium oxide, by generation Sr_1-n(WO₄)_1-xCl_2x:Chemistry needed for nEu Metering is than preparing grinding, high temperature solid state reaction synthesis.

9. according to claim 7 be based on blue light-white light conversion fluorescence powder, preparation method thereof under burst of ultraviolel, its feature exists In the high temperature solid state reaction time is 1~4 hour.