CN103265172B - A method for preparing Sm3+and Bi3+fluorescent glass - Google Patents

Abstract

The invention discloses a kind of YAG:Sm<b> ³⁺</b>, Bi<b> ³⁺the preparation method of </b> fluorescent glass, comprises and first prepares YAG presoma with chemical coprecipitation, then adopt Ba ₂cO ₃1g, Na ₂cO ₃0.4g, H ₃pO ₄0.9g, SiO ₂0.3g, Al ₂o ₃the ratio of 0.56g, YAG presoma 0.8g, obtains the preparation process of fluorescent glass, YAG:Sm<b> prepared by the present invention at 1400 DEG C of temperature lower calcinations after mixing ³⁺</b>, Bi<b> ³⁺</b> fluorescent glass excites lower generation ruddiness near ultraviolet LED chip, can prepare low color temperature white light LED light source.

Description

A kind of YAG:Sm 3+, Bi 3+the preparation method of fluorescent glass

Technical field

The present invention relates to a kind of YAG:Sm ³⁺, Bi ³⁺the preparation method of fluorescent glass.

Background technology

Present stage YAG presoma generally obtains by the following method:

A high-temperature solid phase reaction method

High temperature solid-state method is a kind of traditional synthetic method, the fluorescent material stable performance of synthesizing by this method, and brightness is high, but particle diameter is comparatively large, must through ball-milling processing during application.High-temperature solid phase reaction method is also the method that industrial mass manufacture often adopts.The method comparative maturity, technique is simple, easily operates.

B spray pyrolysis

Spray pyrolysis is the method for synthesizing inorganic functional materials emerging in recent years, the luminescent material prepared in this way is made generally to have uniform spherical morphology, the narrow particle size distribution of particle, this is not only conducive to the luminous intensity improving material, the coating property of fluorescent material can also be improved, and improve the resolving power of luminescence display.But the fluorescent powder grain that this method obtains easily shows hollow morphology, this can cause twinkler brightness reduction and stability to reduce, and the particle with hollow state can lose spherical morphology or broken broken into pieces after high temperature sintering.

C combustion method

Combustion method uses for reference self-propagating high-temperature synthesis, a kind of new preparation method produced after being improved.Its maximum advantage is exactly fast energy-saving.Because combustion reaction time is very short, produce again a large amount of bubbles during reaction, the product porous of generation, in mechanical milling process, crystalline network goes to pot hardly, and therefore after pulverize, luminosity can not obviously decline.In addition, the gas that combustion processes produces has reductibility, does not thus need to protect gas.Weak point is that product purity and luminescent properties have much room for improvement.

D sol-gel processing

Sol-gel processing refers to mineral compound such as alkoxide, through solution, colloidal sol, gel and solidifying, at colloidal sol or gel state compacted under, then is converted into the method for material requested through Overheating Treatment.Sol-gel processing has lot of advantages for high temperature solid-state method.First, the starting raw material reactive behavior of sol-gel processing is high, reacts at molecular level, synthesis temperature is general lower, not only reduces the requirement to reaction process condition and energy consumption, and can obtain the material of different shape, part ratio of components is comparatively even, and particle diameter is less.In addition, do not need complicated equipment in preparation process, technique is flexible, and goods purity is high.But sol-gel processing Production Flow Chart is long, need longer preparation cycle, sol-gel processing generally uses metal alkoxide as raw material, and cost is higher, easily to environment.

At present, the fluorescent material of LED is mainly based on fluorescent material, and commercialization white light LEDs product produces white light for Developing mainstream with blue chip and phosphor combination.Towards large power white light LED, but there is following problems and fail effectively to be solved always in phosphor material powder: (1) is difficult to accurately control fluorescent material thickness and shape with resin or silica gel packaging, occurs inclined blue light or inclined gold-tinted; (2) fluorescent material and packaged material are aging in time, reduction of service life; (3) lack ruddiness, cause color developing low, colour temperature is high.At present, people wish to solve by fluorescent materials such as preparation YAG monocrystalline, YAG pottery, YAG devitrified glasses the deficiency brought with silica gel and resin package fluorescent material.Devitrified glass is composed of an inorganic compound, and easily prepares.Compared with powder, evenly luminous, the colour temperature amplitude of accommodation is wide, and most importantly it is by thermally-stabilised, and light decay is little, is expected to replace powder.To the research of YAG devitrified glass from 05 year Japanese Scientists ShunsukeFujita, research shows: it has very high thermostability, and light decay is very little, luminous desirable.

Summary of the invention

The object of the present invention is to provide a kind of easy to operate, the YAG:Sm of good product quality ³⁺, Bi ³⁺the preparation method of fluorescent glass.

Technical solution of the present invention is:

A kind of YAG:Sm ³⁺, Bi ³⁺the preparation method of fluorescent glass, is characterized in that: comprise the following steps:

(1) preparation of presoma:

Configuration concentration is the Yttrium trinitrate of 0.2mol/L, samaric nitrate, Bismuth trinitrate, aluminum nitrate solution, according to stoichiometric ratio Y:Sm:Bi:Al=2.95-y:0.05:y:10, i.e. Yttrium trinitrate 29.5-10ymL, samaric nitrate 0.5mL, Bismuth trinitrate 10ymL, aluminum nitrate 100mL, y=0, 0.02, 0.04, 0.06, 0.08, metal ion solution separating funnel is at the uniform velocity added with the flow velocity of 3mL/min in the mixed precipitant of 25 DEG C of constant temperature, continuous stirring, dropping process ammoniacal liquor adjustment pH is 6.5, dropping terminates rear continuation and stirs 2h, stop stirring, ageing 12h, outwell supernatant liquid, after precipitation and centrifugal separation, by powders from precipitated precursor through washed with de-ionized water 2 times, ethanol cleans 2 times again to prevent from except anhydrating reuniting, each washing time is 5min, put into the baking oven constant temperature 12h of 120 DEG C afterwards, pulverize to obtain YAG presoma,

(2) preparation of fluorescent glass

Take Ba ₂cO ₃1g, Na ₂cO ₃0.4g, H ₃pO ₄0.9g, SiO ₂0.3g, Al ₂o ₃0.56g, YAG presoma 0.8g, with mortar grinder, makes it mix;

Calcining: above-mentioned mixing material is loaded corundum crucible, 1400 DEG C of calcinings, intensification 4h, insulation 4h, rear jaw is come out of the stove, and naturally cooling obtains product.

After fluorescent material is put into LED, because fluorescent material directly contacts with diode chip for backlight unit in use procedure, after it is luminous, temperature raises, fluorescent material can be caused to produce light decay, affect the life-span, but fluorescent glass is due to himself glass performance, temperature can be avoided to a certain extent on the impact of luminescence medium, increase the service life; The diode that LED uses is a kind of pointolite, tradition silica gel packaging YAG fluorescent powder, due to the unfairness of Silica Surface, distinct colors light can be produced in different angles after light source can be caused to launch, and adopt fluorescent glass, light source uniform emission can be made, no matter be in which angle, the light of same color can be seen, improve photochromic quality; The present invention uses ammoniacal liquor and bicarbonate of ammonia two kinds of precipitation agent precipitation metallic solutions to obtain presoma simultaneously, can guarantee that required metal ion precipitates completely, compensate for the deficiency being used alone a kind of precipitation agent; After the present invention draws the best combined amount of presoma and glass initial raw materials by experiment, consider the doping of rare earth element to the impact of fluorescent glass luminescent properties simultaneously.

Accompanying drawing explanation

Below in conjunction with drawings and Examples, the invention will be further described

Fig. 1 is Y _3-Xal ₅o ₁₂: xSm ³⁺excitation spectrum (λ _em=600nm)

Fig. 2 is Y _3-Xal ₅o ₁₂: xSm ³⁺emmission spectrum (λ _ex=400nm)

Fig. 3 is Y _3-Xal ₅o ₁₂: xSm ³⁺emmission spectrum (λ _ex=470nm)

Fig. 4 is Y _3-Xal ₅o ₁₂: xSm ³⁺excitation spectrum (λ _em=565nm)

Fig. 5 is different monitoring wavelength Y _2.95al ₅o ₁₂: 0.05Sm ³⁺emmission spectrum

Fig. 6 is Y _2.95-yal ₅o ₁₂: 0.05Sm ³⁺, yBi ³⁺excitation spectrum (λ _em=600nm)

Fig. 7 is Y _2.95-yal ₅o ₁₂: 0.05Sm ³⁺, yBi ³⁺emmission spectrum (λ _ex=400nm)

Fig. 8 is that useful range is at 350-650nmY _2.92al ₅o ₁₂: 0.05Sm ³⁺, 0.02Bi ³⁺emmission spectrum (λ _ex=400nm)

Fig. 9 is Y _2.95-yal ₅o ₁₂: 0.05Sm ³⁺, yBi ³⁺emission spectrum (λ _ex=470nm)

Figure 10 is Y _2.95-yal ₅o ₁₂: 0.05Sm ³⁺, yBi ³⁺excitation spectrum (λ _em=565nm)

Figure 11 is different monitoring wavelength Y _2.93al ₅o ₁₂: 0.05Sm ³⁺, 0.02Bi ³⁺emmission spectrum

Figure 12 is Y _2.93al ₅o ₁₂: 0.05Sm ³⁺, 0.02Bi ³⁺wave spectrum (λ is excited under different calcination temperature _em=600nm)

Figure 13 is Y _2.93al ₅o ₁₂: 0.05Sm ³⁺, 0.02Bi ³⁺emission spectrum (λ under different calcination temperature _ex=400nm)

Embodiment

A kind of YAG:Sm ³⁺, Bi ³⁺the preparation method of fluorescent glass, comprises the following steps:

(1) preparation of presoma:

Configuration concentration is the Yttrium trinitrate of 0.2mol/L, samaric nitrate, Bismuth trinitrate, aluminum nitrate solution, according to stoichiometric ratio Y:Sm:Bi:Al=2.95-y:0.05:y:10, i.e. Yttrium trinitrate 29.5-10ymL, samaric nitrate 0.5mL, Bismuth trinitrate 10ymL, aluminum nitrate 100mL, y=0, 0.02, 0.04, 0.06, 0.08, metal ion solution separating funnel is at the uniform velocity added with the flow velocity of 3mL/min in the mixed precipitant of 25 DEG C of constant temperature, continuous stirring, dropping process ammoniacal liquor adjustment pH is 6.5, dropping terminates rear continuation and stirs 2h, stop stirring, ageing 12h, outwell supernatant liquid, after precipitation and centrifugal separation, by powders from precipitated precursor through washed with de-ionized water 2 times, ethanol cleans 2 times again to prevent from except anhydrating reuniting, each washing time is 5min, put into the baking oven constant temperature 12h of 120 DEG C afterwards, pulverize to obtain YAG presoma,

(2) preparation of fluorescent glass

Take Ba ₂cO ₃1g, Na ₂cO ₃0.4g, H ₃pO ₄0.9g, SiO ₂0.3g, Al ₂o ₃0.56g, YAG presoma 0.8g, with mortar grinder, makes it mix;

Calcining: above-mentioned mixing material is loaded corundum crucible, 1400 DEG C of calcinings, intensification 4h, insulation 4h, rear jaw is come out of the stove, and naturally cooling obtains product.

1. samarium content is to YAG:Sm ³⁺the impact of fluorescent glass spectral response curve

In experiment, the content (molar fraction) of samarium gets x=0.02,0.03,0.04,0.05,0.06.Fig. 1, Fig. 2 are Y respectively _3-Xal ₅o ₁₂: xSm ³⁺excite and emmission spectrum.It is monitoring wavelength measurement scope different Sm under 350-500nm that Fig. 1 is expressed as with 600nm ³⁺the YAG:Sm of concentration ³⁺fluorescent glass excite wave spectrum.

As can be seen from the figure Sm ³⁺ion has more rich spectral line in this wave band, Qi Zhongyou: ⁶h _5/2→ ⁴d _3/2(360nm), ⁶h _5/2→ ⁶p _7/2(373nm), ⁶h _5/2→ ⁴f _7/2(400nm), ⁶h _5/2→ ⁴i _9/2(470nm).Peak-peak wavelength is 400nm, derives from ⁶h _5/2→ ⁴f _7/2energy level transition.When showing to excite with 400nm, the most favourable to the fluorescent emission of 600nm.The excitation peak of 400nm is due to Sm ³⁺4f energy level due to spin coupling, splitting is two spectral branch items ⁶f _9/2with ²f _5/2, wherein ²f _5/2for base spectral term.Can transition be formed by the ultraviolet excitation at 400nm place thus send ruddiness.From excitation spectrum, we find to excite broadband near 470nm, although intensity is weaker than 400nm place, when for present stage, photodiode is based on blue chip, and research Sm ³⁺emission spectrum under 470nm is blue-light excited is just very meaningful.

Fig. 2 is with Sm ³⁺exciting the most by force as 400nm monitoring wavelength of ion, the emmission spectrum measured by different concns samarium, useful range is at 550 ~ 660nm, upper as can be seen from figure, has three groups of Sm in emmission spectrum ³⁺the spectral line of emission, in each group, the peak wavelength of highest peak is respectively 565nm, 602nm, 648nm, and wherein 602nm emissive porwer is maximum, and above-mentioned emission spectrum peak is corresponding respectively ⁴g _5/2→ ⁶h _5/2, ⁴g _5/2→ ⁶h _7/2, ⁴g _5/2→ ⁶h _9/2transition.

From Fig. 1 and Fig. 2, different content Sm ³⁺the excitation spectrum of fluorescent glass and the peak wavelength of emmission spectrum substantially constant, but peak value changes.When samarium content is 0.02 ~ 0.05(molar fraction) time, excite with the peak height of emission peak all in rising trend, when samarium content is greater than 0.05(molar fraction) time, excite with the peak height of emission peak on a declining curve.Samarium content is 0.05(molar fraction) time, the peak strength of excitation spectrum and emmission spectrum reaches maximum value.During lower concentration, emissive porwer is along with Sm ³⁺the increase of content and increasing rapidly, reaches maximum when x=0.05, then along with Sm ³⁺the increase of concentration, the strength degradation due to self concentration quenching.According to work luminous intensity I and x [1+ β (x) of D.L.Dexter about inorganic phosphor concentration quenching ^θ/3] ^-1being directly proportional, (in formula, x is the molar fraction of activator ion, and β is constant, θ=6,8, represent eelctric dipole-dipole respectively when 10, eelctric dipole-four pole, electric quadrupole-quadrupolar interaction) can concentration quenching be explained, the quencher of samarium is herein the effect of eelctric dipole-four pole.

Due to Sm ³⁺excitation peak have stronger excitation peak at 470nm place, and consult document at Sm ³⁺emmission spectrum be all measure 470nm place with 400nm place substantially not study usually, so attempt herein being monitor wavelength with 470nm, measure its emission spectrum and must descend Fig. 3, and be that excitation wavelength is surveyed it and excited wave spectrum to obtain Fig. 4 with highest peak.

Can find out with 470nm to be that when monitoring wavelength, the type position, peak of fluorescent glass is substantially constant, but highest peak becomes 565nm by original 602nm.Be that to record excitation spectrum Fig. 4 and Fig. 1 basically identical for monitoring wavelength with 565nm, hereby the emission spectrum that 400nm and 470nm locates compared to obtain Fig. 5 together.

The emissive porwer at 470nm place is starkly lower than 400nm place as seen from Figure 5, based on orange-gold-tinted.The emission wavelength of YAG:Sm fluorescent glass and blue chip matches.

2. bi content is to YAG:Sm ³⁺the impact of fluorescent glass spectral response curve

Adopt the content x=0.05 (molar fraction) of the best of samarium, content (molar fraction) y by changing bismuth in experiment gets 0,0.02,0.04,0.06,0.08 respectively, surveys Y _2.95-yal ₃o ₁₂: 0.05Sm ³⁺, yBi ³⁺exciting of fluorescent glass is respectively Fig. 6 and Fig. 7 with emission spectrum.

Fig. 6 represents with 600nm to be monitoring wavelength measurement scope 350-500nm different B i ³⁺the YAG:Sm of concentration ³⁺, Bi ³⁺fluorescent glass excite wave spectrum.

As can be seen from Fig. 6 Fig. 7, when dopping effect amount y=0 and y>0, fluorescent glass excite with the peak position of emission spectrum and peak shape all similar.Along with doping Bi ³⁺the increase of concentration, excites all first to increase with emissive porwer and weaken afterwards, and concentration quenching phenomena clearly.Work as Bi ³⁺concentration when being 0.02, spectral intensity apparently higher than when not adulterating, the exciting and reach maximum with emissive porwer of fluorescent glass in this time.Work as Bi ³⁺concentration when being 0.04, luminous intensity higher than when not adulterating, but lower than 0.02 intensity.Luminous intensity starts to weaken.Work as Bi ³⁺concentration when being 0.06 and 0.08.Along with Bi ³⁺the increase of content, luminous intensity obviously declines and lower than when not having to adulterate, concentration quenching occurs.

Work as Bi ³⁺be doped in YAG fluorescent glass, due to Bi ³⁺ionic radius and Y ³⁺ionic radius very close, Bi ³⁺that replace is Y in matrix ³⁺position, from YAG:Bi ³⁺excite with emission spectrum in can find out Bi ³⁺excitation peak at about 290nm, emission spectrum is the broadband from 350-500nm, corresponding Bi ³⁺6s layer electronics from 1S ⁰to 3P ¹transition.YAG:Sm as seen from Figure 8 ³⁺, Bi ³⁺in the emission spectrum of fluorescent glass, 350-500nm has very strong emission peak, excites 290nm place in wave spectrum also to have very strong excitation peak, therefore Bi ³⁺absorption energy is luminous.Dopping effect makes exciting of fluorescent glass increase with emissive porwer, and it is luminous that bismuth absorbs energy, Bi ³⁺the broadband emission light of 350-500nm can by Sm ³⁺absorb and energy is passed to Sm ³⁺.Although Bi ³⁺enhance Sm ³⁺intensity, but Bi ³⁺transmitting still very strong.Bi ³⁺can also by mode transferring energies such as resonance to Sm ³⁺make its luminescence enhancement.Bi ³⁺serve as sensitizing agent.Bi ³⁺absorb energy from ground state 1S ⁰arrive excited state 3P ¹, the Bi of excited state ³⁺energy with absorb again and the modes such as transmission that resonate energy transport to Sm ³⁺get back to ground state, Sm ³⁺obtain energy from ground state transition to excited state, to get back to rapidly ground state again to release energy luminescence.Meanwhile, due to Bi ³⁺ratio of ionic radii Y ³⁺ionic radius nearly greatly 15%, this makes Bi ³⁺and Sm ³⁺distance nearer, the speed of transmission ofenergy is faster, and efficiency is higher, and exciting light and radiative intensity significantly strengthen then.Along with Bi ³⁺the increase of concentration, sensitizer ion increased number, simultaneously Bi ³⁺and Sm ³⁺distance reduce, to Sm ³⁺energy transfer efficiency increase, therefore, along with Bi ³⁺the increase of concentration, YAG:Sm ³⁺, Bi ³⁺exciting of fluorescent glass constantly strengthens with emitted luminescence intensity.But work as Bi ³⁺when concentration is increased to a certain degree, multiple Bi ³⁺assemble and form coacervate, the energy that coacervate absorbs is more that radiationless mode discharges, and greatly reduces Sm ³⁺energy transfer efficiency; And, along with Bi ³⁺the increase of concentration, Bi ³⁺between distance also constantly reduce, Bi ³⁺between transmission ofenergy also constantly strengthen, also can affect Sm ³⁺energy transfer efficiency, occur concentration quenching phenomena.

Simultaneously in this group experiment, also determining with 470nm is emission spectrum Fig. 9 of excitation wavelength.And with highest peak 565nm place in Fig. 9 for monitoring wavelength, record its excitation spectrum Figure 10.

With the blue-light excited emmission spectrum Fig. 9 recording each concentration fluorescent glass of 470nm, and maximum peak position records excitation spectrum Figure 10, and with peak, 400nm place type position consistency, intensity is obviously much lower as seen in Figure 11.

3. calcination temperature is to YAG:Sm ³⁺, Bi ³⁺the impact of fluorescent glass spectral response curve

Figure 12 and Figure 13 is Y _2.93al ₅o ₁₂: 0.05Sm ³⁺, 0.02Bi ³⁺exciting and emission spectrum under different calcination temperature.

From Figure 12 Figure 13, calcination temperature is very large on the impact of fluorescent glass luminous intensity.Exciting with emission peak when 900 DEG C is zero substantially, and crystalline phase is not formed.From 1000 DEG C to 1400 DEG C, transmitting and excitation intensity obviously strengthen, and 1400 DEG C of transmittings and excitation intensity reach maximum.In calcination process, 1100 DEG C of YAG crystalline phases basically form, and along with temperature raises, in crystal, ion motion aggravation causes defect in YAG crystalline phase to reduce, and crystalline network is complete gradually, and exciting of fluorescent material strengthens gradually with emissive porwer.Because the highest calcining temperature of atmosphere protection resistance furnace of this experiment is 1400 DEG C, so follow-up higher temperature is not considered.

Conclusion

(1) the present invention first prepares YAG presoma with chemical coprecipitation, with glass matrix by scorification, prepares YAG fluorescent glass 1400 DEG C of calcinings.Compared with silica gel packaging fluorescent material, there are the advantages such as good heat resistance, hardness are high, not fragile.

(2) the YAG fluorescent glass excitation peak peak value prepared of the present invention is at 400nm wave band place, emission peak peak value 600nm place, therefore can be applied near ultraviolet LED and excite generation ruddiness, prepares low color temperature white light LED light source.

(3) along with Sm ³⁺concentration increase, luminous intensity is first increased in decline, when adulterate molar weight be 0.05 time, luminous intensity reaches maximum.

(4) adulterate a small amount of Bi ³⁺higher luminous intensity can be obtained, doping number affect luminous intensity but do not affect the position excited with emission peak.Work as Bi ³⁺when doping molar weight is near 0.02, the luminous intensity of YAG fluorescent glass reaches the strongest.Bi ³⁺there is sensibilized, but can die out when its concentration is excessive.

(5) calcination temperature is very large on the impact of luminous intensity, and 1400 DEG C of effects are best.

Claims (1)

1. a YAG:Sm ³⁺, Bi ³the preparation method of fluorescent glass, is characterized by: comprise the following steps:

(1) preparation of presoma:

Configuration concentration is the Yttrium trinitrate of 0.2mol/L, samaric nitrate, Bismuth trinitrate, the metal ion solution of aluminum nitrate, according to stoichiometric ratio Y:Sm:Bi:Al=2.95-y:0.05:y:10, i.e. Yttrium trinitrate 29.5-10ymL, samaric nitrate 0.5mL, Bismuth trinitrate 10ymL, aluminum nitrate 100mL, y=0, 0.02, 0.04, 0.06, 0.08, in the ammoniacal liquor that above-mentioned metal ion solution separating funnel is at the uniform velocity added 25 DEG C of constant temperature with the flow velocity of 3mL/min and bicarbonate of ammonia mixed precipitant, continuous stirring, dropping process ammoniacal liquor adjustment pH is 6.5, dropping terminates rear continuation and stirs 2h, stop stirring, ageing 12h, outwell supernatant liquid, after precipitation and centrifugal separation, by powders from precipitated precursor through washed with de-ionized water 2 times, ethanol cleans 2 times again to prevent from except anhydrating reuniting, each washing time is 5min, put into the baking oven constant temperature 12h of 120 DEG C afterwards, pulverize to obtain YAG presoma,

(2) preparation of fluorescent glass

Take Ba ₂cO ₃1g, Na ₂cO ₃0.4g, H ₃pO ₄0.9g, SiO ₂0.3g, Al ₂o ₃0.56g, YAG presoma 0.8g, with mortar grinder, makes it mix;

Calcining: above-mentioned mixing material is loaded corundum crucible, 1400 DEG C of calcinings, intensification 4h, insulation 4h, rear jaw is come out of the stove, and naturally cooling obtains product.