CN103923644B

CN103923644B - Natural minerals attapulgite prepares yellow fluorescent powder Sr3siO5: M1, M2(M1=Ce3+or Eu2+, M2=Li+or Ba2+)

Info

Publication number: CN103923644B
Application number: CN201310015159.6A
Authority: CN
Inventors: 刘伟生; 王文杰
Original assignee: Lanzhou University
Current assignee: Lanzhou University
Priority date: 2013-01-15
Filing date: 2013-01-15
Publication date: 2016-08-03
Anticipated expiration: 2033-01-15
Also published as: CN103923644A

Abstract

The invention provides one utilizes natural minerals attapulgite to prepare LED yellow fluorescent powder Sr₃SiO₅∶M₁, M₂(M₁=Ce³⁺Or Eu²⁺, M₂=Li⁺Or Ba²⁺) method, its technical process comprises the following steps successively, A: attapulgite clay is placed in mortar grinding；B: take a certain amount of concentrated acid, dilution post-heating is to 50～95 DEG C, and the attapulgite clay after grinding is added thereto, stirring reaction 1～6h；C: reactant filters after being cooled to room temperature, washs 2～6 times, and product is placed in 40～85 DEG C dry 6～24h in vacuum drying oven；D: by ground for product 200 mesh sieves, by Sr_3‑x‑ySiO₅∶xM₁, yM₂Mole metering ratio of (0 ＜ x≤0.15,0≤y≤0.05) adds raw material, grinds and is uniformly placed in reducing atmosphere calcining, obtains Sr₃SiO₅∶M₁, M₂Fluorescent material.The method is advantageous in that after natural attapulgite clay is carried out simple process, can calcine and obtain Sr within the scope of wider temperature₃SiO₅Single-phase, its emission peak, 550～570nm, has certain advantage in terms of preparing white light LEDs, improves the added value of attapulgite clay, expand the range of application of attapulgite clay.

Description

Natural minerals attapulgite prepares yellow fluorescent powder Sr3SiO5∶M1, M2(M1=Ce3+Or Eu2+, M2=Li+Or Ba2+)

Technical field:

Art of the present invention is inorganic mineral material application, is specially and utilizes a kind of natural inorganic mineral attapulgite synthesis Yellow fluorescent powder used by white light LED Sr₃SiO₅∶M₁, M₂(M₁=Ce³⁺Or Eu²⁺, M₂=Li⁺Or Ba²⁺) method.

Background technology:

Attapulgite clay is called for short attapulgite clay, has another name called Paligorskite, is a kind of silicate mineral containing Shuifu County's magnalium, and typical chemical formula is Mg₅Si₈O₂₀(OH)₂(OH₂)₄·4H₂O, structure is unique, and the diameter of single fiber crystalline substance is 20～about 70nm, length is about 0.5～5 μm, is a kind of natural monodimension nanometer material, has many excellent properties, it is a kind of important nonmetal clay mineral with special construction and function, is referred to as " king of thousand soil, the soil of general-purpose ".Product is directed not only to the traditional industries such as chemical industry, machinery, the energy, automobile, light industry, metallurgy, building materials, and enters the high-tech industry with information, biology, Aero-Space, ocean development, new material and new forms of energy as representative.Along with new application requires constantly occur, its range of application also will be widened further.China's attapulgite clay rich in mineral resources, cheap, but research starting ratio is later, and its research and development, production and level of processing are relatively backward, and attapulgite clay product is mainly used in than the industry of lower end (primary product and some low value-added products).Therefore, exploitation high technology content, variation, the attapulgite clay product of different industries demand can be met, will be the direction of China's attapulgite clay industry development.

White light light emitting diode gets more and more people's extensive concerning with features such as efficient, energy-saving and environmental protection and long-lives, has been counted as replacing the New Solid light source of conventional illumination sources, has become the study hotspot of current lighting field.At present, the approach about three kinds of white light LEDs, i.e. light conversion type, polychromatic combination type and Multiple-quantum well-type are obtained.Light conversion type refers to be coated on LED light-converting material, and the blue light partially absorbing LED emission produces the gold-tinted of the 555nm complementary with blue light, utilizes lens principle by complementary gold-tinted and blue light to obtain white light；Or being coated in by several light-converting material on the LED of generation luminescence, the transmitting all absorbing LED produces red, green, blue transmitting, thus is combined and obtains white light emission.The impact of the factors such as complex art, technique, production cost, the most most possibly realize industrialization is light conversion type white light LEDs, and the research of light-converting material is also advanced subject in current luminescent material research field.The mainstream scheme of the white light LEDs of commercialization be utilize GaN blue-light semiconductor chip excite produce 550nm gold-tinted mix Ce³⁺Yttrium aluminium garnet [Y₃Al₅O₁₂∶Ce³⁺(YAG)∶Ce³⁺] fluorescent material, blue light and gold-tinted mixing obtain white light, but synthesized white light colour temperature is higher, and color rendering index is low.If the white light of warm white can be obtained by the gold-tinted of fluorescent material to long wave red shift, thus improves the color rendering properties of white light LEDs.Based on YAG: Ce³⁺The defect that fluorescent material exists, the research of white light LEDs new phosphors becomes current vital task.

Silicate systems fluorescent material has the excellent properties such as excitation spectrum wide ranges (240～500nm), emission spectrum wide ranges (430～630nm) continuously adjustabe, light conversion efficiency be high and ageing-resistant, it is highly suitable near ultraviolet chip or blue chip, the white light LEDs that even aeruginous chip is excited.The Sr of Park seminar report₃SiO₅∶Eu²⁺, Ba²⁺(Park J K, Kim C H, Park S H, et al.Appl Phys Lett, 2004,84:1647-1649), Sr₃SiO₅∶Eu²⁺The Sr of (Park J K, Choi K J, Yeon J H, et al.Appl Phys Lett, 2006,88:043511) and Jang seminar report₃SiO₅∶Ce³⁺, Li⁺(Jang H S, Jeon D Y. Appl Phys Lett, 2007, the silicate material such as 90:041906), exciting this fluorescent material can obtain white light LEDs by the LED chip of 405nm or 460nm, such material is compared with YAG:Ce, and emission peak is closer to long wave direction, therefore, highly beneficial to preparing warm white light LED component.

But, the preparation condition of silicate material is harsher, and its synthesis temperature is higher, and system phase composition is complicated, and structure is wayward, such as at synthesis Sr₃SiO₅Time, that frequently result in is Sr₃SiO₅And Sr₂SiO₄Compound phase, it is difficult to obtain the Sr of single thing phase₃SiO₅.As Lee expects etc. at research Sr₃SiO₅∶Eu²⁺Spectral quality time, when less than 1400 DEG C, obtain is four angle-style crystallographic systems Sr₃SiO₅With monoclinic system Sr₂SiO₄The system that coexists (Lee expects, Yang Zhiping, Wang Zhijun. photon journal, 2008,37 (10): 2001-2004).

For the problems referred to above, the previous important research direction of mesh be exactly be easily controlled at one under conditions of obtain single thing phase, can be used for the silicate material of white light LEDs.

Summary of the invention:

The invention provides one utilizes natural minerals attapulgite to prepare LED yellow fluorescent powder Sr₃SiO₅∶M₁, M₂(M₁=Ce³⁺Or Eu²⁺, M₂=Li⁺Or Ba²⁺) method, will be after natural attapulgite clay processes in hot acid, through washing and drying, by Sr_3-x-ySiO₅∶xM₁, yM₂Mole metering ratio of (0 ＜ x≤0.15,0≤y≤0.05) adds Sr₂CO₃、BaCO₃、Li₂CO₃、Eu₂O₃And CeO₂, grind and be uniformly placed on high-temperature calcination in reducing atmosphere, obtain Sr₃SiO₅∶M₁, M₂(M₁=Ce³⁺Or Eu²⁺, M₂=Li⁺Or Ba²⁺) fluorescent material.The method is advantageous in that after natural attapulgite clay is carried out simple process, can calcine and obtain Sr within the scope of wider temperature₃SiO₅Single-phase, by the different active ions (M that adulterates₁, M₂), its emission peak is adjustable in the range of 550～570nm, has certain advantage in terms of preparing white light LEDs, improves this natural minerals value-added content of product, expands the range of application of attapulgite clay.

The technical scheme is that pretreatment and the fluorescent material Sr of presoma attapulgite₃SiO₅∶M₁, M₂(M₁=Ce³⁺Or Eu²⁺, M₂=Li⁺Or Ba²⁺) preparation, its technical process includes the grinding of attapulgite, acid treatment, washs, sieves and being blended and calcining in reducing atmosphere of other raw materials.

The step of concrete preparation is as follows:

1) preparation of presoma attapulgite: attapulgite is placed in mortar grinding by (a)；B () takes a certain amount of concentrated acid, add distilled water diluting, be heated to 50～95 DEG C, and the attapulgite after grinding is added thereto, stirring reaction 1～6h；C () reactant filters after being cooled to room temperature, distilled water wash 2～6 times, and product is placed in 40～85 DEG C dry 6～24h in vacuum drying oven；D () is by ground for product 200 mesh sieves, standby.

Concentrated acid therein can be HCl, HNO₃Or H₂SO₄.When concentrated acid is HCl, add distilled water diluting to 3～10mol/L；Concentrated acid is HNO₃Time, add distilled water diluting to 3～12mol/L；Concentrated acid is H₂SO₄Time, add distilled water diluting to 3～15mol/L.

2) calcining: detect through plasma spectrometer (ICP), determine SiO in the attapulgite after process₂Mass fraction, by Sr_3-x-ySiO₅∶xM₁, yM₂(0 ＜ x≤0.15,0≤y≤0.05) (M₁Can be Ce³⁺Or Eu²⁺, M₂Can be Li⁺Or Ba²⁺) mole metering than weighing the attapulgite (with the cubage of Si in attapulgite clay) after process, Sr₂CO₃、BaCO₃、Li₂CO₃、Eu₂O₃And CeO₂, add the grinding of a small amount of ethanol and be uniformly placed in corundum crucible, in reducing atmosphere (5%H₂+ 95%N₂It is cooled to room temperature after 1350～1500 DEG C of calcinings 2～8h in), grinds to obtain fluorescent material Sr₃SiO₅∶M₁, M₂(M₁=Ce³⁺Or Eu²⁺, M₂=Li⁺Or Ba²⁺)。

Accompanying drawing illustrates:

Fig. 1 different temperatures synthesizing yellow fluorescent material Sr₃SiO₅∶0.05Ce³⁺Single crystal diffraction (XRD) collection of illustrative plates；

Fig. 2 yellow fluorescent powder Sr₃SiO₅∶0.05Ce³⁺Excitation-emission (PL) spectrum；

The natural attapulgite clay of Fig. 3 and yellow fluorescent powder Sr₃SiO₅∶0.05Ce³⁺Scanning electron microscope (SEM) photo.

Specific implementation method:

In order to be more fully understood that the present invention, present disclosure is expanded on further below in conjunction with embodiment.

Embodiment

1. raw material and experimental facilities

(1) experimental raw:

Xuyi County of attapulgite Jiangsu Province

The commercially available analytical pure of strontium carbonate

Cerium oxide Xi'an chemicals factory 99.99%

(2) experimental facilities

High-temperature tubular atmosphere furnace WLS-1600 Hefei Ke Jing Instrument Ltd.

Vacuum drying oven DZF-6020 Shanghai Yiheng Scientific Instruments Co., Ltd

2. the pretreatment of attapulgite

Taking 100ml concentrated hydrochloric acid, addition distilled water diluting, to 10mol/L, is heated to 80 DEG C, and the attapulgite 10g after grinding is added thereto, stirring reaction 2.5h；Reactant filters after being cooled to room temperature, and distilled water wash 3 times, product is placed in 60 DEG C of dry 12h in vacuum drying oven；By ground for product 200 mesh sieves, standby.

3. yellow fluorescent powder Sr₃SiO₅∶0.05Ce³⁺Preparation

By Sr_2.95SiO₅∶0.05Ce³⁺Mole metering than the attapulgite after weighing process, (ICP tests to obtain SiO₂Mass fraction be 72%), Sr₂CO₃And CeO₂, add the grinding of a small amount of ethanol and be uniformly placed in corundum crucible, in reducing atmosphere (5%H₂+ 95%N₂It is cooled to room temperature after 1350～1500 DEG C of calcining 4h in), grinds to obtain fluorescent material Sr₃SiO₅∶0.05Ce³⁺。

4. performance test

X-ray diffraction (XRD) test in experiment is to carry out on the Max-2400 type X-ray diffractometer that Rigaku (Rigaku) produces.Use Cu target K_αRayThe monochromator used is the diffracted beam graphite bent crystal.Running voltage 40kV, electric current 60mA, divergent slit DS is 1 °, and antiscatter slits SS is 1 °, and receiving slit RS is 0.3mm.The mode used in test is scanning continuously, and scanning speed is 15 °/min, and stepping is 0.02 °, and sweep limits is 10～80 °.

FLS-920T fluorometric investigation system test is used to excite the characteristics of luminescence of lower sample in ultra-violet (UV) band.Excitation and emission spectra slit during sample test is 0.5nm, and step footpath is 1.0nm.

JSM-5600 type scanning electron microscope is used to carry out the scanning electron microscopy analysis (SEM) of sample.

The content of element silicon in attapulgite clay after employing IRIS ER/S type plasma spectrometer (ICP) test acid treatment.

Properties of product are shown in accompanying drawing 1～3:

Fig. 1 is different temperatures synthesizing yellow fluorescent material Sr₃SiO₅∶0.05Ce³⁺Single crystal diffraction (XRD) collection of illustrative plates, within the temperature range of 1380～1480 DEG C calcine, all can get Sr₃SiO₅Single-phase；

Fig. 2 is yellow fluorescent powder Sr₃SiO₅∶0.05Ce³⁺Excitation-emission (PL) spectrum, shown in solid for sample under the exciting of 400nm, it is emitted as a broad peak of 450～750nm scopes, belongs to Ce³⁺5d-4f transition, its emission peak, can be as Yellow fluorescent powder used by white light LED at 561nm；Dotted line show the sample absorption curve when 561nm monitors, and is two peaks in the range of 275～525nm, is respectively belonging to Ce³⁺4f (²F_5/2,²F_7/2)-5d transition；

Fig. 3 is natural attapulgite clay and yellow fluorescent powder Sr₃SiO₅∶0.05Ce³⁺Scanning electron microscope (SEM) photo, A figure is natural attapulgite clay, is its typical acicular morphology, and B figure is through the Sr that obtains of calcining₃SiO₅∶0.05Ce³⁺, for irregular particle shape.

Claims

1. a LED yellow fluorescent powder Sr₃SiO₅:M₁, M₂Preparation method, described M₁It is Ce³⁺Or Eu²⁺, M₂It is Li⁺ Or Ba²⁺, its preparation technology is as follows:

1) preparation of presoma attapulgite: attapulgite is placed in mortar grinding by (a)；B () takes concentrated acid and adds distilled water diluting, Being heated to 50～95 DEG C, the attapulgite after grinding is added thereto, stirring reaction 1～6h；C () reactant is cooled to room temperature Rear filtration, distilled water wash 2～6 times, product is placed in 40～85 DEG C dry 6～24h in vacuum drying oven；D product is ground by () Honed 200 mesh sieves, standby；

2) calcining: by Sr_3-x-ySiO₅:xM₁, yM₂Mole metering than weighing the attapulgite after process, Sr₂CO₃、BaCO₃、 Li₂CO₃、Eu₂O₃And CeO₂, wherein 0 ＜ x≤0.15,0≤y≤0.05, add ethanol grinding and be uniformly placed in corundum crucible, In reducing atmosphere 5%H₂+ 95%N₂In 1350～1500 DEG C calcining 2～8h after be cooled to room temperature, grind to obtain fluorescent material Sr₃SiO₅: M₁, M₂。

2. the preparation method as described in claim 1, after process, the amount of attapulgite is according to the cubage of wherein Si.

3. the preparation method as described in claim 1, concentrated acid therein is HCl, HNO₃Or H₂SO₄；When concentrated acid is HCl, add Enter distilled water diluting to 3～10mol/L；Concentrated acid is HNO₃Time, add distilled water diluting to 3～12mol/L；Concentrated acid is H₂SO₄ Time, add distilled water diluting to 3～15mol/L.