CN103602336A

CN103602336A - Preparation method of divalent europium activated alkaline earth metal phosphate fluorescent powder

Info

Publication number: CN103602336A
Application number: CN201310557943.XA
Authority: CN
Inventors: 王吉有; 王剑波; 王超; 段苹
Original assignee: Beijing University of Technology
Current assignee: Beijing University of Technology
Priority date: 2013-11-12
Filing date: 2013-11-12
Publication date: 2014-02-26

Abstract

The invention relates to a preparation method of divalent europium activated alkaline earth metal phosphate fluorescent powder. The preparation method is characterized by comprising the steps of weighting BaCO3, CaCO3, La2O3, NH4H2PO4 and Eu2O3 according to the molar ratio of Ba2CaLa1-x(PO4)3:xEu<2+>, wherein H3BO3 is used as a reaction cosolvent; uniformly grinding all the raw materials, then, placing the raw materials into an alumina crucible, placing the alumina crucible into a muffle furnace, heating to 200 DEG C in the air atmosphere, sintering at constant temperature for 2h, cooling, and then, taking out a sample to be uniformly ground again; heating again to sinter the ground sample, wherein carbon powder is used a reducing agent; heating from the room temperature to 300 DEG C, then, heating at the speed of 10 DEG C/min until the temperature is raised to 1250 DEG C, and then, preserving the heat for 4h; cooling along with the furnace to obtain a fluorescent matrix, thereby preparing the fluorescent powder of the Ba2CaLa1-x(PO4)3:xEu<2+>, wherein the fluorescent powder can be used as a fluorescent material.

Description

A kind of Bivalence europium enabled alkaline earth metal phosphate phosphor preparation method

Technical field:

The present invention relates to rare earth luminescent material field, be specifically related to a kind of novel blue alkali earth metal phosphate fluorescent material.

Background technology:

Luminescent material is generally comprised of host compound and active activator, and host compound is called matrix, and active activator is optically active impurity that has of a small amount of even trace of mixing in matrix, sometimes also can be doped into sensitizing agent.General formula is expressed as: matrix+activator ion+sensitizer ion.Phosphate fluophor developing history is long, and synthesis temperature is lower, and selected cost of material is cheap, and has different application function, so the phosphate matrix of development of new seems particularly important.A ₃la (PO ₄) ₃(A=Ca, Ba, Mg, Zn, Sr) alkali earth metal phosphate fluorescent material matrix belongs to isometric system, due to Ba ²⁺and Ca ²⁺ionic radius is similar, therefore can replace mutually, to prepare novel phosphate matrix.

The advantages such as white light LEDs is long, energy-efficient with its life-span, environmental protection, be described as after incandescent light, luminescent lamp and high-voltage gas discharging light the 4th generation lighting source, have broad application prospects.Because being mainly blue led, implementation method irradiates yellow fluorescent powder and the near ultraviolet excitated red-green-blue mixed fluorescent powder of ultraviolet, therefore preparing novel blue LED fluorescent material is still current research emphasis, and blue-fluorescence is also widely used in the demonstration of electronic curtain.

The present invention adopts high temperature solid-state method to synthesize a kind of novel blue alkali earth metal phosphate fluorescent material, has mixed europium ion, and use reduction method to become divalent europium in this material, and this luminescent powder is blue colour fluorescent powder.

Summary of the invention:

The invention reside in above-mentioned the deficiencies in the prior art, aim to provide a kind of Bivalence europium enabled alkaline earth metal phosphate phosphor preparation method.

A Bivalence europium enabled alkaline earth metal phosphate phosphor preparation method, is characterized in that: according to Ba ₂caLa _1-x(PO ₄) ₃: xEu ²⁺mole proportioning takes: BaCO ₃, CaCO ₃, La ₂o ₃, NH ₄h ₂pO ₄, Eu ₂o ₃; Use H ₃bO ₃as reaction solubility promoter, H ₃bO ₃mole proportioning is Ba ₂caLa _1-x(PO ₄) ₃: xEu ²⁺3%; X=0.06 wherein;

After grinding evenly, pack alumina crucible into, put into retort furnace, under air atmosphere, at 200 ℃, sintering is 2 hours, makes NH ⁴⁺be decomposed into NH ₃emit, cooling after, take out sample and again grind evenly;

To the sintering that again heats up of the sample after grinding, use carbon dust as reductive agent.From room temperature, it is 10 ℃/min that temperature heats up, until temperature is raised to 1250 ℃, keeps 4 hours at this temperature.

By technique scheme, the invention provides a kind of Bivalence europium enabled alkaline earth metal phosphate phosphor preparation method.And can be used as the Ba of the photoluminescence fluorescent characteristic that shows blue light ₂caLa _1-x(PO ₄) ₃: xEu ²⁺luminescent material.

Accompanying drawing explanation:

Figure 1B a ₂caLa _0.94(PO ₄) ₃: 0.06Eu ²⁺the emmission spectrum of luminescent material (solid line) and excitation spectrum (dotted line)

Fig. 2 Ba ₂caLa (PO ₄) ₃and Ba ₂caLa _0.94(PO ₄) ₃: 0.06Eu ²⁺the XRD figure of material

Embodiment

Be below the embodiment in conjunction with subordinate list and accompanying drawing, further illustrate technical essential of the present invention.

Embodiment mono-

According to the Ba of table 1 preparation 2g ₂caLa _0.94(PO ₄) ₃: 0.06Eu ²⁺the raw materials quality of luminescent material, takes respectively BaCO ₃(AR), CaCO ₃(AR), La ₂o ₃(99.99%), NH ₄h ₂pO ₄(AR), Eu ₂o ₃(AR), use H ₃bO ₃(AR) as reaction solubility promoter, shared mole of proportioning is 3%.According to novel blue fluorescent material reduction method sintering procedure in technical scheme, finally obtain Ba ₂caLa _0.94(PO ₄) ₃: 0.06Eu ²⁺fluorescent material.

Calculate Eu ²⁺feed molar proportioning after ion doping, takes raw material, after grinding evenly, packs alumina crucible into, puts into retort furnace, and under air atmosphere, at 200 ℃, sintering 2h, makes NH ⁴⁺be decomposed into NH ₃emit, cooling after, take out sample and again grind evenly.

Use three crucibles, be divided into large, medium and small three types.Pre-sintered sample is put into minimum crucible.In medium-sized crucible bottom, put into a small amount of carbon dust, monkey is put into medium-sized crucible, when covering to monkey, (unavailable other materials replace, and during lid, are careful, can be fixing once with adhesive tape between monkey and small lid, to press from both sides lastblock crucible fragment.Object is to make CO that carbon dust produces enter monkey to reduce), after building, in medium-sized crucible, fill up carbon dust, cover monkey (noting not making carbon dust to fall in monkey) completely, fill up.Then, cover the lid of medium-sized crucible, then put into large crucible (large crucible bottom is put into a small amount of carbon dust), fill carbon dust, cover medium-sized crucible, fill up, then cover the lid of large crucible, put into retort furnace sintering.Its control process is, first raises the temperature to 300 ℃, and then to heat up be 10 ℃/min to temperature, until temperature is raised to 1250 ℃, at this temperature, keeps 4h, after sintering completes, guarantees that temperature drops to 100 ℃ and opening retort furnace door below.Take out crucible, successively open crucible cover, with spoon, take out carbon dust.Owing to having fragment between monkey and lid, therefore pick and place and remove carbon dust and want slowly patient, in order to avoid contaminated samples.Take out after monkey, sample fully ground, make a kind of brand-new chemistry and optical property stablize, can be by ultraviolet and near ultraviolet excitated blue colour fluorescent powder.

Fig. 1 is Ba ₂caLa (PO ₄) ₃matrix and Ba ₂caLa _0.94(PO ₄) ₃: 0.06Eu ²⁺the XRD figure of luminescent material, comparison Ba ₃la (PO ₄) ₃standard x RD spectrogram, find that diffraction peak is identical, but angle of diffraction is offset to some extent, without any assorted peak, show that this kind of matrix is a kind of novel substance B a ₂caLa (PO ₄) ₃alkali earth metal phosphate, and Eu ²⁺a small amount of doping of ion is to Ba ₂caLa (PO ₄) ₃matrix structure is without impact.

Fig. 2 is Ba ₂caLa _0.94(PO ₄) ₃: 0.06Eu ²⁺the transmitting of luminescent material and exciting light spectrogram, do not show Eu in figure ³⁺characteristic spectrum, illustrate that the doping europium ion of entering is all reduced to divalence.This kind of fluorescent material can effectively excite under ultraviolet and near-ultraviolet light region, under 364nm excites, shows the strongest fluorescence efficiency, and emmission spectrum is shown as the peak bag of crossing over bluish-green wavelength, and the chromaticity coordinates of Show Color is in blue region.

Table 1 is that the present invention prepares 2gBa ₂caLa _0.94(PO ₄) ₃: 0.06Eu ²⁺the raw materials quality of luminescent material.

Table 1

Claims

1. a Bivalence europium enabled alkaline earth metal phosphate phosphor preparation method, is characterized in that: according to Ba ₂caLa _1-x(PO ₄) ₃: xEu ²⁺mole proportioning takes: BaCO ₃, CaCO ₃, La ₂o ₃, NH ₄h ₂pO ₄, Eu ₂o ₃; Use H ₃bO ₃as reaction solubility promoter, H ₃bO ₃mole proportioning is Ba ₂caLa _1-x(PO ₄) ₃: xEu ²⁺3%; X=0.06 wherein;

After grinding evenly, pack alumina crucible into, put into retort furnace, under air atmosphere, be warmed up to 200 ℃, constant temperature sintering 2 hours, makes NH ⁴⁺be decomposed into NH ₃emit, cooling after, take out sample and again grind evenly;

Use carbon dust as reductive agent, the sample heating after grinding, raises the temperature to 300 ℃, and then temperature intensification is 10 ℃/min, until temperature is raised to 1250 ℃, keeps 4 hours at this temperature.