CN102936497B - Main emission peak changeable and adjustable fluorescent material and preparation method thereof - Google Patents

Abstract

The invention discloses a main emission peak changeable and adjustable fluorescent material and a preparation method thereof and relates to a light-emitting diode (LED) illuminating/displaying fluorescent material and a preparation method thereof. The fluorescent material is an alkaline earth oxygen fluorine silicon aluminum acid salt fluorescent material. The chemical general formula is Mx-zY6-x-y-zAl11-xLxO25.5-0.5kFk: yCe3+, zMn2+, wherein Ce3+ and Mn2+ are luminescence center ions, the x is larger than or equal to 0 and smaller than or equal to 1.5, the y is larger than or equal to 0.01 and smaller than or equal to 0.16, the z is larger than or equal to 0 and smaller than or equal to 0.2, the k is larger than 0 and smaller than or equal to 0.01, M is Mg2+ or Ba2+, L is Si4+ or Zr4+, according to the chemical general formula, MgO, MgF2, Al2O3, AlF3, SiO2, ZrO2, BaF2, BaCO3, MnCO3 and CeO2 are mixed in a closed container to obtain a mixture, and the mixture is subjected to heat preservation in a reduction furnace of 1620 DEG C at H2 atmosphere, cooling, crushing, grading and sieving to obtain the alkaline earth oxygen fluorine silicon aluminum acid salt fluorescent material. According to the fluorescent material and the preparation method thereof, the main emission peak of green, yellow and orange is changeable and adjustable, the fluorescent material is used for white light LED illuminating/displaying, under the excitation of blue light LED, high luminous efficiency can be achieved, and the wavelength is in a range from 530nm to 585nm.

Description

A kind of main peak of launching changes adjustable fluorescent material and preparation method thereof

Technical field

The present invention relates to a kind of fluorescent material and preparation method thereof, particularly the fluorescent material and preparation method thereof of the Application Areas such as a kind of LED illumination/display.

Background technology

White light LEDs is a kind of New Solid green lighting technique of efficient, energy-saving and environmental protection, is described as 21 century forth generation lighting source.The implementation of white light LEDs mainly contains: 1) adopt red, green, blue three primary colours chip to prepare White LED with high color rendering property; 2) InGaN blue-ray LED is adopted to excite yttrium aluminum garnet structure Y ₃al ₅o ₁₂: Ce (YAG:Ce ³⁺) yellow fluorescent powder; 3) UV-LED is adopted to excite red, green, blue fluorescent material to prepare White LED with high color rendering property.From current White-light LED illumination Development Technology trend, white light LEDs implementation, mainly based on fluorescence conversion, namely excites yellow fluorescent powder YAG:Ce, (Ba, Sr) SiO by blue-ray LED (450 ~ 470nm) ₄: Eu ²⁺, i.e. blue-ray LED+yellow fluorescent powder; Or ultraviolet LED (380 ~ 400nm)) excitated blue, green and red fluorescence powder, namely purple LED+RGB phosphor combination obtains white light LEDs.Therefore, the good and bad light efficiency to white light LEDs of fluorescent material performance, light decay and color developing etc. serve vital effect.

CN201110309206.9 discloses a kind of method that high temperature solid-state method prepares yttrium aluminum garnet structure YAG:Ce fluorescent RE powder, according to Y ₃al ₅o ₁₂: Ce fluorescent material chemical formula mol ratio takes Y ₂o ₃or Gd ₂o ₃or their mixture, Al ₂o ₃or Ga ₂o ₃or their mixture, CeO ₂and fusing assistant, in High Temperature Furnaces Heating Apparatus reducing atmosphere, roasting 2 ~ 6 hours, obtains YAG:Ce fluorescent RE powder.

CN201110132661.6 discloses a kind of LED fluorescent powder, this fluorescent material is with cerium, chromium ion or Ce+Cr mix the garnet phase material for activation center altogether, its element at least one is chosen from Y and rare earth, have at least a kind of from Al, Ga, In, Sc, choose in V, the improvement that elemental vanadium is conducive to fluorescence efficiency is introduced in matrix, the introducing of vanadium contributes to the perfection of lattice improving host doped, simultaneously, vanadium doping can play sensitized fluorescence effect to the luminescence center in matrix, and the red fluorescence composition that the introducing of chromium more can bring more than 600nm abundant, improve the display of fluorescent material.

CN201110186964.6 discloses a kind of silicate yellow orange fluorescent powder, uses general formula Sr _2-x-y-zlu _yba _zsiO ₄: xEu ²⁺the material composition represented, in formula, x is the mole number of europium atom, and y is the mole number of lutetium atom, and z is the mole number of barium atom, 0.005≤x≤0.15,0.01≤y≤0.15,0≤z≤1.5.Under 460nm is blue-light excited, its emmission spectrum is the banded spectral line being positioned at 470 ~ 700nm, and along with the increase of barium incorporation, centre wavelength moves between 515 ~ 570nm.

The LED fluorescent material of above-mentioned CN201110309206.9, CN201110132661.6 belongs to aluminate YAG:Ce system; CN201110186964.6 belongs to silicate (Sr, Ba) ₂siO ₄: Eu ²⁺fluorescent material, the fluorescent material of CN201110132661.6 with the addition of toxic element Cr as light emitting ionic.

At present, the colour temperature of the lighting source incandescent light that people use and luminescent lamp is general all lower than 6000K, the ability having penetrating fog and steam because of low colour temperature light is strong, light is soft, the high plurality of advantages of road reflection rate, but the emmission spectrum of commercial YAG:Ce fluorescent material, launch main peak and can only reach 560nm, red color light component is less, causes the colour temperature of white light LED part higher (6000 ~ 8000K), and colour rendering index is on the low side (< 80).Therefore, need by adding orange, that red fluorescence powder improves white light LEDs color developing.Although silicate fluorescent powder (Sr, Ba) ₂siO ₄: Eu ²⁺have and launch main peak 515 ~ 570nm change adjustable feature, but there is larger light decay in silicate material system fluorescent material, the shortcomings such as thermostability is low, particularly red light portion can only reach about 570nm, can not meet the requirement improving white light LEDs color developing far away.

Summary of the invention

The object of the invention is to overcome the deficiencies in the prior art, there is provided that a kind of White-light LED illumination/display is green, yellow, the change of orange emission main peak is adjustable, there is the fluorescent material and preparation method thereof of higher luminous efficiency, wavelength 530 ~ 585nm under blue-ray LED excites.

Of the present invention should be extensively alkaline earth fluorine oxygen silico-aluminate fluorescent material, and its chemical general formula is expressed as: M _x-zy _6-x-y-zal _11-xl _xo _25.5-0.5kf _k: yCe ³⁺, zMn ²⁺, wherein Ce ³⁺and Mn ²⁺for luminescent center ion, in general formula: 0≤x≤1.5,0.01≤y≤0.16,0≤z≤0.2,0 < k≤0.01; M is Mg ²⁺or Ba ²⁺, L is Si ⁴⁺or Zr ⁴⁺; According to chemical general formula, by analytically pure MgO, MgF ₂, NH ₄f, Al ₂o ₃, AlF ₃, SiO ₂, ZrO ₂, BaF ₂, BaCO ₃, MnCO ₃and CeO ₂, in chemical constitution ratio batching mixing, batch mixing 40 hours in encloses container, then by mixture at H ₂under % < 5% atmosphere, in 1620 DEG C of reduction furnaces, be incubated 6 hours, cooling, broken classification, cross 500 eye mesh screens, obtain the alkaline earth fluorine oxygen silico-aluminate fluorescent material that granularity is about 3 ~ 20 μm.

As shown in Figure 1, in this material system, there is a kind of Y in alkaline earth fluorine oxygen silicon zircoaluminate fluorescent material crystalline structure ³⁺case, two kinds of Al ³⁺case.Because Al ³⁺, Si ⁴⁺, Zr ⁴⁺ionic radius is respectively 0.061, and 0.040 and 0.065nm, and Y ³⁺, Mg ²⁺, Ba ²⁺, Mn ²⁺and Ce ³⁺ionic radius is respectively 0.089, and 0.072,0.135,0.08 and 0.13nm.According to the similar close principle of ionic radius, Si ⁴⁺, Zr ⁴⁺alO in preferential replacement alkaline earth fluorine oxygen silicon zircoaluminate fluorescent material crystalline structure ₄and AlO ₆case, and Mg ²⁺, Ba ²⁺, Mn ²⁺and Ce ³⁺plasma then replaces the YO in alkaline earth fluorine oxygen silicon zircoaluminate fluorescent material crystalline structure ₈case.

Ce ³⁺crystal field engery level cracking and surrounding coordination environment have considerable influence.Si ⁴⁺electronegativity is 1.9, and Al ³⁺electronegativity be 1.6.As the Si that an electronegativity is larger ⁴⁺the Al that ionic replacement electronegativity is less ³⁺time, make Ce ³⁺around the covalency in ligand field strengthens, and causes Ce ³⁺produce larger engery level cracking, minimum 5d orbital energy level d ₁energy level center of gravity obviously declines, thus makes Ce ³⁺transmitting there is red shift.Same principle, works as Zr ⁴⁺replace Al ³⁺time, because Zr ⁴⁺electronegativity be 1.33, make Ce ³⁺around the covalency in ligand field reduces, thus reduces Ce ³⁺crystal field engery level cracking, minimum 5d orbital energy level d ₁energy level center of gravity obviously rises, thus makes Ce ³⁺transmitting there is blue shift.

Therefore, according to above-mentioned mechanism, Zr in adjustment matrix components ⁴⁺, Si ⁴⁺content, adjustable Ce ³⁺crystal field splitting energy level size residing for case, thus make Ce ³⁺emission of ions changes adjustable from green (530nm) to yellow (570nm).

Due to Zr ⁴⁺, Si ⁴⁺replace Al ³⁺during ion, will produce non-equivalence and replace, and easily form defect, thus form luminous cancellation center, this point is very unfavorable to raising rare-earth luminescent material luminous efficiency.Therefore, in fluorescent material system of the present invention, alkaline earth ion is introduced as Mg ²⁺, Ba ²⁺, adopt Mg ²⁺, Ba ²⁺non-equivalence replaces Y ³⁺case, thus make fluorescent material crystalline structure keep charge balance.

But, although by mixing Si ⁴⁺ce in fluorescent material can be made ³⁺emission of ions from 545nm red shift to about 570nm, but in order to improve the colour rendering index of low color temperature white light LED, needs Ce ³⁺launch further red shift.Because of Ce ³⁺minimum 5d orbital energy level be positioned at blue light 460nm, under blue-light excited, there is higher luminous efficiency, but, Mn ²⁺although some absorb at 430nm, luminescence is more weak.Therefore, we design a kind of Ce in the present invention ³⁺and Mn ²⁺the fluorescent material system of mixing altogether, utilizes Ce ³⁺→ Mn ²⁺transmission ofenergy principle (ET), obtains fluorescent orange material.First Ce is passed through ³⁺ion d ₁orbital energy level absorbs blue light, then passes to Mn radiationless for energy ²⁺ion ⁴t ₁(G) energy level is mated, finally by Mn ²⁺'s ⁴t ₁(G) → ⁶a ₁energy level transition, realizes orange-colored light broadband emission, launches main peak and is positioned at 585nm.

Alkaline earth fluorine oxygen silicon zircoaluminate fluorescent material of the present invention has higher luminous efficiency under blue-light excited, compensate for YAG:Ce fluorescent material simultaneously and lacks the shortcomings such as red light portion.

Fig. 2,3 sets forth embodiment 1,2,3, the XRD of the fluorescent material of 4 preparations and utilizing emitted light spectrogram, by Fig. 2,3 is visible, add a small amount of silicon and do not affect this material crystal structure, along with the Si content in fluorescent material increases, emmission spectrum moves to 570nm from 545nm is red gradually.Fig. 4 gives fluorescent material scanning electron microscope sem photo prepared by embodiment 1, and this fluorescent material is spherical particle, and grain graininess is between 3 ~ 10 μm.Fig. 5,6 give encapsulation obtains white light LEDs utilizing emitted light spectrogram and chromaticity coordinate figure, and this white light LEDs is under 350mA electric current excites, and colour temperature Tc=5823K, chromaticity coordinates X=0.3241, Y=0.3676, light efficiency is 121.5 lumens/watt, colour rendering index 78.5.

Fig. 7,8 give embodiment 5,6, and the fluorescent materials of 7 preparations excite, utilizing emitted light spectrogram, along with Ce concentration increase time, to excite, emmission spectrum red shift gradually.Fig. 9,10 give encapsulation obtains white light LEDs utilizing emitted light spectrogram and chromaticity coordinate figure, and this white light LEDs is under 350mA electric current excites, and colour temperature Tc=5430K, chromaticity coordinates X=0.3352, Y=0.4072, light efficiency is 113.2 lumens/watt, colour rendering index 79.2.

Figure 11,12,13,14 give fluorescent material XRD crystalline structure diffraction prepared by embodiment 8, excite, utilizing emitted light spectrogram and X-ray fluorescence spectra (XPS).By doping Zr ⁴⁺element, crystalline structure is substantially constant, but finds from Figure 14 fluorescent material x-ray photoelectron energy spectrogram (XPS), in this material structure outside Y, Al, O, Ce, contains Zr ⁴⁺and Mg ²⁺deng element, illustrate in fluorescent material of the present invention, Zr ⁴⁺and Mg ²⁺ion enters in lattice.From Ce ³⁺excitation spectrum finds, 360nm excitation band obviously reduces, and Ce ³⁺the obvious blue shift of minimum 5d orbital energy level.Find at emmission spectrum equally, emmission spectrum gradually blue shift moves about 545nm, thus realizes the greener fluorescent material of emmission spectrum blue shift acquisition.Figure 15,16 give encapsulation obtains white light LEDs utilizing emitted light spectrogram and chromaticity coordinate figure, and this white light LEDs is under 350mA electric current excites, and colour temperature Tc=5658K, chromaticity coordinates X=0.3282, Y=0.3818, light efficiency is 106.9 lumens/watt, colour rendering index 79.2.

Figure 17,18,19,20 give fluorescent material XRD crystalline structure diffraction prepared by embodiment 11, excite, utilizing emitted light spectrogram and X-ray fluorescence spectra (XPS).By doping Si ⁴⁺and Mn ²⁺element, crystalline structure is substantially constant, but finds from Figure 20 fluorescent material x-ray photoelectron energy spectrogram (XPS), in this material structure outside Y, Al, O, Ce, contains Si ⁴⁺, Mn ²⁺deng element, illustrate in fluorescent material of the present invention, Si ⁴⁺and Mg ²⁺ion enters in lattice.From Ce ³⁺excitation spectrum find, there are three place's excitation bands altogether, be respectively 297,334 and 462nm excitation band obviously reduce, wherein 297nm is from Mn ²⁺excitation band, as shown in figure 18.Figure 19 gives Ce ³⁺and Mn ²⁺ion mixes the utilizing emitted light spectrogram of fluorescent material altogether, is found by Gauss curve fitting swarming, and this emission band main 530 and 585 and 733nm tri-emission bands are formed, and wherein 530nm emission band is from Ce ³⁺5d → ²f _5/2energy level transition, 585nm and 733nm is then from Mn ²⁺'s ⁴t ₁→ ¹a ₆energy level transition.Figure 21, Figure 22 give encapsulation and obtain white light LEDs utilizing emitted light spectrogram and chromaticity coordinate figure, and this white light LEDs is under 350mA electric current excites, and colour temperature Tc=3947K, chromaticity coordinates X=0.4109, Y=0.4778, light efficiency is 98.5 lumens/watt, colour rendering index 86.6.

Accompanying drawing explanation

Fig. 1 fluorescent material crystalline structure of the present invention schematic diagram;

Fig. 2 embodiment 1,2, the crystalline structure X diffractogram (XRD) of 3,4 fluorescent materials;

Fig. 3 embodiment 1,2,3,4 fluorescent material emmission spectrum;

The fluorescent material scanning electron microscope (SEM) photograph (SEM) that Fig. 4 embodiment 1 obtains;

Fig. 5 encapsulates the white light LEDs spectrogram obtained;

Fig. 6 encapsulates the white light LEDs chromaticity diagram obtained;

Fig. 7 embodiment 5,6,7 fluorescent material exciting light spectrogram;

Fig. 8 embodiment 5,6,7 fluorescent material utilizing emitted light spectrogram;

Fig. 9 encapsulates the white light LEDs spectrogram obtained;

Figure 10 encapsulates the white light LEDs chromaticity diagram obtained;

The crystalline structure X diffractogram (XRD) of fluorescent material prepared by Figure 11 embodiment 8;

Fluorescent material exciting light spectrogram prepared by Figure 12 embodiment 8;

Fluorescent material utilizing emitted light spectrogram prepared by Figure 13 embodiment 8;

Fluorescent material x-ray photoelectron energy spectrogram (XPS) prepared by Figure 14 embodiment 8;

Figure 15 encapsulates the white light LEDs spectrogram obtained;

Figure 16 encapsulates the white light LEDs chromaticity diagram obtained;

The crystalline structure X diffractogram (XRD) of fluorescent material prepared by Figure 17 embodiment 11;

Fluorescent material exciting light spectrogram prepared by Figure 18 embodiment 11;

Fluorescent material utilizing emitted light spectrogram prepared by Figure 19 embodiment 11;

Fluorescent material x-ray photoelectron energy spectrogram (XPS) prepared by Figure 20 embodiment 11;

Figure 21 encapsulates the white light LEDs spectrogram obtained;

Figure 22 encapsulates the white light LEDs chromaticity diagram obtained.

Embodiment

According to chemical general formula M _x-zy _6-x-y-zal _11-xl _xo _25.5-0.5kf _k: y.Ce ³⁺, z.Mn ²⁺, by analytically pure MgO, MgF ₂, NH ₄f, Al ₂o ₃, AlF ₃, SiO ₂, ZrO ₂, BaF ₂, MnCO ₃and CeO ₂, by table 1,2 and 3 chemical constitution ratios batching mixing, batch mixing 40 hours in encloses container, then by mixture at H ₂under % < 5% atmosphere, in 1620 DEG C of reduction furnaces, be incubated 6 hours, cooling, broken classification, cross 500 eye mesh screens, obtain the alkaline earth fluorine oxygen silico-aluminate fluorescent material that granularity is about 3 ~ 20 μm.With blue-light LED chip (450 ~ 460nm) combination package, obtain white light LEDs.

Phosphor emission main peak is tested by national fluorescent material testing standard GB/T 14634.2-2010 and is determined, excitation spectrum is tested by FLS-920 transient state steady-state fluorescence spectrograph.The crystalline structure (XRD) of fluorescent material is determined by GB/T 19421.1-2003 testing standard.The colour temperature (CCT) of white light LEDs, colour rendering index (Ra), emmission spectrum, luminous efficiency (lm/w) are determined by GB/T 24982-2010 testing method.Fluorescent material photoelectron spectrum (XPS) is determined by ISO15472-2001 testing method.

Table 1 fluorescent material chemical constitution

Table 2 fluorescent material chemical constitution

Table 3 fluorescent material chemical constitution

Claims (2)

1. launch main peak and change an adjustable fluorescent material, it is characterized in that chemical general formula is expressed as: M for alkaline earth fluorine oxygen silico-aluminate fluorescent material _x-zy _6-x-y-zal _11-xl _xo _25.5-0.5kf _k: yCe ³⁺, zMn ²⁺, wherein Ce ³⁺and Mn ²⁺for luminescent center ion, in general formula: 0 < x≤1.5,0.01≤y≤0.16,0≤z≤0.2,0 < k≤0.01; M is Mg ²⁺or Ba ²⁺, L is Si ⁴⁺or Zr ⁴⁺; According to chemical general formula, by analytically pure MgO, MgF ₂, NH ₄f, Al ₂o ₃, AlF ₃, SiO ₂, ZrO ₂, BaF ₂, BaCO ₃, MnCO ₃and CeO ₂, in chemical constitution ratio batching mixing, batch mixing 40 hours in encloses container, then by mixture at H ₂under % < 5% atmosphere, in 1620 DEG C of reduction furnaces, be incubated 6 hours, cooling, broken classification, cross 500 eye mesh screens, obtain the alkaline earth fluorine oxygen silico-aluminate fluorescent material that granularity is 3 ~ 20 μm.

2. transmitting main peak according to claim 1 changes the preparation method of adjustable fluorescent material, it is characterized in that according to chemical general formula, by analytically pure MgO, MgF ₂, NH ₄f, Al ₂o ₃, AlF ₃, SiO ₂, ZrO ₂, BaF ₂, BaCO ₃, MnCO ₃and CeO ₂, in chemical constitution ratio batching mixing, batch mixing 40 hours in encloses container, then by mixture at H ₂under % < 5% atmosphere, in 1620 DEG C of reduction furnaces, be incubated 6 hours, cooling, broken classification, cross 500 eye mesh screens, obtain the alkaline earth fluorine oxygen silico-aluminate fluorescent material that granularity is 3 ~ 20 μm.