CN102321470A - Double core-shell fluorescent material and preparation method thereof - Google Patents

Abstract

The invention relates to a fluorescent material, which has a chemical composition expression of a(Ba, Sr)Si2O11:xPb@SiO2@My, wherein a is greater than or equal to 0.5 and is less than or equal to 1.0; d is greater than or equal to 0 and is less than or equal to 0.5; x is greater than or equal to 0.001 and is less than or equal to 0.1; y is greater than 0 and is less than or equal to 1*10<-2>; @ is a coat; M is a core; SiO2 is an intermediate shell layer; and a(Ba, Sr)Si2O11:xPb@SiO2@My is an outer shell layer. The core-shell luminous material coated by metal particles has the advantages of improving internal quantum efficiency and enhancing luminous intensity, along with high stability. The luminous material has controllable size and appearance, has spherical appearance of high stacking density and is suitable for improving display effect.

Description

A kind of dual core-shell fluorescent material and preparation method thereof

Technical field

The present invention relates to the luminescent material technical field, relate in particular to a kind of fluorescent powder with core-shell structure and preparation method thereof.

Background technology

Show with the development of lighting engineering and bring huge change for the mankind's life that the especially appearance of white light LEDs is LED from identification function to one step of substance that illumination functions is stepped out.White light LEDs more can better reflect the true colors of irradiating object near daylight.Because it also has pollution-free, long lifetime, vibration resistance and shock proof distinguishing feature; See from technical standpoint; White light LEDs is undoubtedly the most advanced technology of LED, will become the light source of new generation of 21 century---the 4th generation electric light source, the application market of white light LEDs will be very extensive.

At present in the prior art field, realize illumination and the mode that shows, being main through the method for ultraviolet chip or blue chip excitation fluorescent material or the method for the ultraviolet ray excited fluorescent material of low-pressure mercury discharge generation.But owing to receive the restriction of fluorescent material, all there is certain limitation in these methods.

In patent US5998925, US6998771, ZL00801494.9, all be to utilize blue chip to excite cerium activated rare-earth garnet fluorescent material (like Y ₃Al ₅O ₁₂: Ce, (Y, Gd) ₃(Al, Ga) ₅O ₁₂: Ce, be called for short YAG; Or the Tb-garnet, be called for short TAG), send through the blue chip excitation fluorescent material that the blue light of gold-tinted and part blue chip is compound to go out white light.In this method, employed fluorescent material has significant limitation at the application and the aspect of performance of white light LEDs.At first, this fluorescent material excite scope in the scope of 420～490nm, the most effectively excite in the scope of 370～470nm, do not excite for the short wavelength side zone and the green glow zone of UV-light zone and visible light; Secondly, the emmission spectrum maximum of the fluorescent material of this rare-earth garnet structure can only arrive about 540nm, lacks red composition, causes the colour rendering index of white light LEDs lower.

In patent US6649946, USPA20040135504, CN1522291A, CN1705732A, CN1596292A, CN1596478A, US6680569, related is rare-earth activated nitride or the nitrogen oxide fluorescent material that the UV-blue region can effectively excite.Effective excitation wavelength range of the fluorescent material of this method increases to some extent; Transmitting boundary also can be from the green glow to ruddiness; But the luminosity of this fluorescent material is lower, and manufacturing cost is higher, uses as the LED fluorescent material of practicability to also have significant limitation.

As related among the patent USPA6351069 be sulfide red fluorescent material, this fluorescent material can be used as the complementary color composition and joins in the white light LEDs, in order to remedy colour rendering index, reduces colour temperature.But the luminosity of all-sulphide phosphor is low, though improve colour rendering index, reduces the luminous efficiency of LED; And, its chemicalstability and loss of properties on aging, and corrode chip, shortened the work-ing life of LED.

In fact, existing other authorized or all kinds of fluorescent materials that the patent of applying for is set forth in, the excitation spectrum of aluminate class fluorescent material is difficult to be implemented in effectively exciting of visible region; Silicates or halogen silicate class fluorescent material then aspect thermally-stabilised performance poor slightly.

Summary of the invention

Therefore, the purpose of this invention is to provide a kind of fluorescent powder with core-shell structure, not only electroconductibility is good, and the pattern class is spherical, have luminous intensity preferably, luminous uniformity coefficient and with the sticking power of substrate.

Another goal of the invention of the present invention has provided the preparation method of a kind of technology fluorescent powder with core-shell structure simple, with low cost;

The chemical constitution expression of said fluorescent material is: a (Ba, Sr) Si ₂O ₁₁: xPbSiO ₂M _ySiO ₂M _y, 0.5≤a≤1.0 wherein; 0≤d≤0.5; 0.001≤x≤0.1; 0<y≤1 * 10 ^-2, be to coat; M is a kernel; SiO ₂Be subshell; A (Ba, Sr) Si ₂O ₁₁: xPbSiO ₂M _yBe outer shell, M is at least a in Ag, Au, Pt, Pd or the Cu metal nanoparticle.

Preferably, 0.5≤a≤0.8; 0≤d≤0.15; 0.001≤x≤0.01; 0<y≤1 * 10 ^-3

According to second aspect of the present invention, a kind of preparation method of fluorescent powder with core-shell structure is provided, may further comprise the steps:

Step 1: adopt the StOber method to M metal nanoparticle coated Si O ₂, obtain containing the solution that coats product, wherein M is at least a in Ag, Au, Pt, Pd or the Cu metal nanoparticle;

Step 2: by the metering ratio, in containing the solution that coats product, add the nitrate soln of Ba, Si, Sr or nitrate soln or the hydrochloride solution of hydrochloride solution or oxide compound and Pb, stir; Drip excessive oxalic acid solution, stir to make and precipitate fully, then the pH to 5 of regulator solution～6; Stir, ageing is filtered; Washing and filtering product, drying obtain the fluorescent powder with core-shell structure presoma;

Step 3: with the fluorescent powder with core-shell structure presoma in 100～150 ℃ of thermal treatment 2～6h, again in reducing atmosphere in 800～1000 ℃ of thermal treatment 6～8h, cooling obtains coating the fluorescent powder with core-shell structure that the particulate form is formed by different substances.

In the preparation method of fluorescent powder with core-shell structure of the present invention, preferably, said step 1 comprises:

Step 1.1: with the water-soluble aqueous solution that obtains Vinylpyrrolidone polymer of Vinylpyrrolidone polymer, then the M metal nanoparticle is joined in the aqueous solution of Vinylpyrrolidone polymer, stir, obtain M metal nanoparticle solution.

Step 1.2: adopt the StOber method to the M metal nanoparticle coated Si O in the solution in the step 1.1 ₂

In the preparation method of fluorescent powder with core-shell structure of the present invention, the reducing atmosphere in the said step 3 is meant that by volume ratio be the atmosphere that 95: 5 nitrogen and hydrogen gas mixture, CO gas, hydrogen forms.

Fluorescent powder with core-shell structure of the present invention is a nuclear with Ag, Au, Pt, Pd or Cu metal nanoparticle, with spherical SiO ₂Be the middle layer, consist of a (Ba, Sr) Si ₂O ₁₁: xPbSiO ₂M _yFluorescent material be outer shell.Fluorescent powder with core-shell structure of the present invention is owing to introduce SiO ₂And metal nanoparticle; The conductivity of fluorescent material is improved; Thereby has higher luminous intensity; Simultaneously because pattern with almost spherical, thus luminous uniformity coefficient and also be improved with the sticking power of substrate, so fluorescent powder with core-shell structure of the present invention has good luminescent properties.

Among the preparation method of fluorescent powder with core-shell structure of the present invention, utilize PVP solution that metal nanoparticle has been carried out surface treatment, make metal nanoparticle be more prone to coated Si O ₂, at the outside SiO that forms of metal nanoparticle ₂Nanometer ball.

Adopt the StOber method to metal nanoparticle coated Si O among the present invention ₂, this method is simple to operate, technical maturity, the SiO that security deposit's metal nano-particle coats ₂All have spherical or subglobose pattern.The StOber method specifically can be referring to following document: controllable growth (the Controlled Growth of Monodisperse Silica Spheres in the Micron Size Range.JOURNAL OF COLLOID AND INTERFACE SCIENCE of monodispersity silicon ball in the nanoscale scope; 26,62--69 (1968)).

The preparation method of fluorescent powder with core-shell structure of the present invention, technology is simple, with low cost, and the shell structured fluorescence powder of stating that makes is not introduced other impurity, and quality product is high, can be widely used in the manufacturing of luminescent material.

Description of drawings

Fig. 1 is 0.6 (Ba, Sr) Si of the embodiment of the invention 1 preparation ₂O ₁₁: 0.005PbSiO ₂Ag _0.00175Fluorescent powder with core-shell structure (with 1 expression) and 0.6 (Ba, Sr) Si ₂O ₁₁: the emmission spectrum comparison diagram of 0.005P (with 2 expressions).

Wherein, emmission spectrum figure obtains through 200 ~ 250nm optical excitation.

Embodiment

Embodiment 1:

0.6(Ba,?Sr)Si ₂O ₁₁:0.005PbSiO ₂Ag _0.00175

Get in the deionized water that 0.2g PVP is dissolved in 10mL, stir 15min, adding 7mL concentration is 1 * 10 ^-3The Ag particle solution of mol/L stirs 12h.Get above-mentioned surface-treated Ag particle solution, adopt the StOber method metal nanoparticle coated Si O ₂, promptly add 25mL absolute ethyl alcohol, 6mL ammoniacal liquor, 1mL tetraethoxy (TEOS) and 5mL deionized water respectively, stirring reaction 6h.Then by above-mentioned chemical formula add the metering ratio Ba (NO ₃) ₂Solution, SiO ₂, Sr (NO ₃) ₂Solution and lead nitrate solution stir 15min, drip 15mL 1M oxalic acid solution then, stir 15min.Use ammoniacal liquor to regulate pH value 5, stir 10min then after, deposition is filtered, use the deionized water washing and precipitating, drying.

The exsiccant powder is ground, then in air in 120 ℃ of following sintering 3h, be 95: 5 N at last in volume ratio ₂And H ₂In 800 ℃ of thermal treatment 6h, promptly get 0.6 (Ba, Sr) Si after the cooling in the mixed gas ₂O ₁₁: 0.005PbSiO ₂Ag _0.00175Fluorescent powder with core-shell structure.

Fig. 1 is 0.6 (Ba, Sr) Si of the embodiment of the invention 1 preparation ₂O ₁₁: 0.005PbSiO ₂Ag _0.00175Fluorescent powder with core-shell structure and 0.6 (Ba, Sr) Si ₂O ₁₁: the emmission spectrum comparison diagram of 0.005Pb fluorescent material.As shown in Figure 1,1 is 0.6 (Ba, Sr) Si of present embodiment preparation among the figure ₂O ₁₁: 0.005PbSiO ₂Ag _0.00175The emmission spectrum of fluorescent powder with core-shell structure, 2 is 0.6 (Ba, Sr) Si ₂O ₁₁: the emmission spectrum of 0.005Pb fluorescent material.Can find out 0.6 (Ba, Sr) Si of present embodiment through contrast ₂O ₁₁: 0.005PbSiO ₂Ag _0.00175Fluorescent powder with core-shell structure and 0.6 (Ba, Sr) Si ₂O ₁₁: 0.005Pb fluorescent material is compared, and luminous intensity is about 2.3 times of the latter.

Embodiment 2:

0.8(Ba,?Sr)Si ₂O ₁₁:0.01PbSiO ₂Au _0.002

Get in the deionized water that 0.2g PVP is dissolved in 10mL, stir 15min, adding 8mL concentration is 1 * 10 ^-3The Au particle solution of mol/L stirs 12h.Get above-mentioned surface-treated Au particle solution, adopt the StOber method metal nanoparticle coated Si O ₂, promptly add 25mL absolute ethyl alcohol, 6mL ammoniacal liquor, 1mL tetraethoxy (TEOS) and 5mL deionized water respectively, stirring reaction 6h.Then by above-mentioned chemical formula add the metering ratio Ba (NO ₃) ₂Solution, SiO ₂, Sr (NO ₃) ₂Solution and lead nitrate solution stir 15min, drip 15mL 1M oxalic acid solution then, stir 15min.Use ammoniacal liquor to regulate pH value 5, stir 10min then after, deposition is filtered, use the deionized water washing and precipitating, drying.

The exsiccant powder is ground, then in air in 140 ℃ of following sintering 3h, be 95: 5 N at last in volume ratio ₂And H ₂In 1000 ℃ of thermal treatment 8h, promptly get 0.8 (Ba, Sr) Si after the cooling in the mixed gas ₂O ₁₁: 0.01PbSiO ₂Au _0.002Fluorescent powder with core-shell structure.

Embodiment 3:

0.7(Ba,?Sr)Si ₂O ₁₁:0.07PbSiO ₂Pd _0.0004

Get in the deionized water that 0.2g PVP is dissolved in 10mL, stir 15min, adding 4mL concentration is 1 * 10 ^-3The Pd particle solution of mol/L stirs 12h.Get above-mentioned surface-treated Pd particle solution, adopt the StOber method metal nanoparticle coated Si O ₂, promptly add 25mL absolute ethyl alcohol, 6mL ammoniacal liquor, 1mL tetraethoxy (TEOS) and 5mL deionized water respectively, stirring reaction 6h.Then by above-mentioned chemical formula add the metering ratio Ba (NO ₃) ₂Solution, SiO ₂, Sr (NO ₃) ₂Solution and lead nitrate solution stir 15min, drip 15mL 1M oxalic acid solution then, stir 15min.Use ammoniacal liquor to regulate pH value 5, stir 10min then after, deposition is filtered, use the deionized water washing and precipitating, drying.

The exsiccant powder is ground, then in air in 130 ℃ of following sintering 5h, be 95: 5 N at last in volume ratio ₂And H ₂In 1000 ℃ of thermal treatment 6h, promptly get 0.7 (Ba, Sr) Si after the cooling in the mixed gas ₂O ₁₁: 0.07PbSiO ₂Pd _0.0004Fluorescent powder with core-shell structure.

The foregoing description 2 and 3 gained nucleocapsid fluorescent material have emmission spectrum through 200 ~ 250nm optical excitation between 400 ~ 500nm, the luminous intensity of nucleocapsid fluorescent material is 2 ~ 3 times of seedless shell structured fluorescence powder luminous intensity.

Claims (3)

1. a fluorescent material is characterized in that, the chemical constitution expression is: a (Ba, Sr) Si ₂O ₁₁: xPbSiO ₂M _ySiO ₂M _y, 0.5≤a≤1.0 wherein; 0≤d≤0.5; 0.001≤x≤0.1; 0<y≤1 * 10 ^-2, be to coat; M is a kernel; SiO ₂Be subshell; A (Ba, Sr) Si ₂O ₁₁: xPbSiO ₂M _yBe outer shell, M is at least a in Ag, Au, Pt, Pd or the Cu metal nanoparticle.

2. fluorescent material according to claim 1 is characterized in that, 0.5≤a≤0.8; 0≤d≤0.15; 0.001≤x≤0.01; 0<y≤1 * 10 ^-3

3. claim 1 or 2 said Preparation of Fluorescent Material methods is characterized in that may further comprise the steps:

Step 1: adopt the StOber method to M metal nanoparticle coated Si O ₂, obtain containing the solution that coats product, wherein M is at least a in Ag, Au, Pt, Pd or the Cu metal nanoparticle;

Step 2: by the metering ratio, in containing the solution that coats product, add the nitrate soln of Ba, Si, Sr or nitrate soln or the hydrochloride solution of hydrochloride solution or oxide compound and Pb, stir; Drip excessive oxalic acid solution, stir to make and precipitate fully, then the pH to 5 of regulator solution～6; Stir, ageing is filtered; Washing and filtering product, drying obtain the fluorescent powder with core-shell structure presoma;

Step 3: with the fluorescent powder with core-shell structure presoma in 100～150 ℃ of thermal treatment 2～6h, again in reducing atmosphere in 800～1000 ℃ of thermal treatment 6～8h, cooling obtains coating the fluorescent powder with core-shell structure that the particulate form is formed by different substances.

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