CN105694886A - Eu (Eu)2+Preparation method and application of doped fluosilicate-based luminescent material - Google Patents

Abstract

The invention discloses Eu²⁺The doped fluoate fluorescent material is prepared by rare earth ion activated fluoate base material with chemical formula of Ca₂Nb₂O₆F，<i>x</i>Is Eu²⁺The doping amount of (A) is not more than 0.0001<i>x</i>Less than or equal to 0.15. The fluosilicate-based luminescent material disclosed by the invention emits blue light with the wavelength of 400-480 nanometers under the excitation of ultraviolet light, and can be applied to various illumination displays and photoluminescence chromaticity adjustment by taking the ultraviolet light as an excitation source. The invention adopts a high-temperature solid phase method to obtain the fluorescent powder with uniform granularity, good dispersibility, high luminous efficiency and good chemical stability, and the preparation method has lower requirements on production cost and equipment and is easy to carry out industrial production.

Description

A kind of preparation method and application of Eu2+ doped fluoride-based luminescent material

technical field

The invention relates to a preparation method and application of a luminescent material, in particular to a preparation method and application of an Eu ²⁺ doped fluorate-based luminescent material, and belongs to the technical field of inorganic luminescent materials.

Background technique

In recent years, white LEDs have attracted attention and become a new generation of green, environmentally friendly and energy-saving lighting sources. Due to the simple synthesis, stable performance, low cost and fast luminous response of phosphor powder for W-LED, it has been studied by more and more people, and the new luminescent material doped with rare earth ions has also become an important part of materials science and lighting display. research hotspots in the field.

From the perspective of human lighting history, white LED is known as the fourth-generation lighting source that is most likely to replace traditional lighting equipment (such as incandescent lamps and fluorescent lamps). Rare-earth three-primary-color fluorescent lamps use red, blue, and green phosphors, and the color of the illuminated object is pure, without distortion, and has no pollution to the environment. However, the luminous efficiency of commercialized white LEDs is generally low, and has not reached the minimum efficiency required by standard fluorescent lamps. It is necessary to continuously improve the quantum efficiency of the chip. At the same time, yellow and green phosphors at home and abroad are very mature in packaging applications, while the luminous efficiency and stability of blue phosphors are far from comparable to other powders. Therefore, it is necessary to develop new types of phosphors with high efficiency and good thermal stability , long life, low cost blue phosphor can effectively improve the quality of white LED light.

The currently developed blue phosphors excited by europium ions for LEDs mainly include phosphate-based, vanadate-based, borate-based, and oxyfluoride-based compounds, which are limited by the disadvantages of poor stability, high cost, and complex synthesis processes. Applications in LEDs. Fluorate is also a phosphor matrix material with excellent performance, which has the advantages of high stability, low cost and simple preparation process. Patent CN201410079962.0 reported the preparation method of Eu ³⁺ ion-doped gadolinium fluoride/gadolinium fluoride sodium crystal phase controllable luminescent powder; patent CN201110048219.5 reported a multi-element solvothermal method to prepare rare earth doped lanthanum fluoride luminescent powder The method of hollow nano powder belongs to the technical field of rare earth ion doped luminescent nano powder preparation technology; patent CN201010567623.9 reports a fluorine-containing electroluminescent material and its preparation method. The novel fluorophosphate-based blue fluorescent powder Ca _2-2x Eu _2x NbO ₆ F synthesized by the present invention has not been reported. It is synthesized by high-temperature solid-phase method, has low reaction temperature, saves energy, is simple to operate, and is easy for industrial production. It has potential application prospects.

Contents of the invention

The purpose of the present invention is to provide a preparation method and application of a fluoride fluorescent powder that has simple preparation process, low raw material cost, high crystallinity, high luminous efficiency, environmental friendliness, and emits blue light under ultraviolet light excitation.

In order to achieve the above purpose, the technical solution adopted by the present invention is: a Eu ²⁺ doped fluoride-based luminescent material, characterized in that: the chemical formula is Ca _2-2x Eu _2x NbO ₆ F, wherein x is Eu ²⁺ Doping replaces the molar percentage of Ca ²⁺ , and the value range is 0.0001≤x≤0.15; the phosphor emits blue fluorescence with a wavelength of 400-480 nanometers under the excitation of ultraviolet light with a wavelength of 270 nanometers.

A preparation method of Eu ²⁺ doped fluoride-based luminescent material, characterized in that a high-temperature solid phase method is adopted, comprising the following steps:

(1) Weigh the raw materials according to the stoichiometric ratio of the corresponding elements in the general formula Ca _2-2x Eu _2x NbO ₆ F, compound containing calcium ions, compounds containing europium ions and compounds containing niobium ions, and grind them to make them evenly mixed. , x is the molar percentage coefficient of Eu ²⁺ replacing Ca ²⁺ , 0.0001≤x≤0.15;

(2) Calcining the mixture in an air atmosphere, the calcination temperature is 300-650°C, the calcination time is 2-10 hours, and this step is repeated twice;

(3) Cool the calcined mixture naturally, grind and mix evenly, and calcinate in a carbon powder reducing atmosphere, the calcining temperature is 650-900°C, and the calcining time is 5-12 hours to obtain a fluoride blue phosphor .

The compound containing calcium ions is one of calcium carbonate, calcium bicarbonate, calcium hydroxide, calcium nitrate, calcium oxide and calcium fluoride.

The compound containing europium ions is one of europium oxide, europium nitrate and europium fluoride.

The compound containing niobium ions includes one of niobium pentoxide, niobium dioxide, niobium hydroxide, niobium tetrafluoride and niobium pentafluoride.

The calcination temperature in step (2) is 350-600°C, and the calcination time is 3-8 hours; the calcination temperature in step (3) is 600-850°C, and the calcination time is 5-10 hours.

A Eu ²⁺ doped fluoride-based luminescent material can be applied to various lighting displays and photoluminescent chromaticity adjustments using ultraviolet light as an excitation source.

Compared with the prior art, the advantages of the technical solution of the present invention are:

1. The fluoride salt prepared by the present invention has good chemical stability, is also a fluorescent synthetic material with high luminous efficiency, and has high crystallinity and visible light transmittance. The Eu ²⁺ activated blue fluorescent powder of the present invention can emit blue light of 400-480 nanometers under the excitation of ultraviolet light, and has pure chromaticity.

2. The novel fluorine-based blue fluorescent powder provided by the present invention has simple preparation process, low raw material cost, high crystallinity, and is environmentally friendly. The synthesis temperature in the preparation process is low, and energy consumption and cost are reduced.

3. The fluorine-based blue phosphor powder prepared by the present invention has good thermal stability and color rendering property, high luminous efficiency, and is beneficial to the preparation of high-power LEDs.

Description of drawings

Fig. 1 is an X-ray powder diffraction pattern of Ca _1.9998 Eu _0.0002 NbO ₆ F prepared according to the technical scheme of Example 1 of the present invention.

Fig. 2 is an SEM image of Ca _1.9998 Eu _0.0002 NbO ₆ F prepared according to the technical scheme of Example 1 of the present invention.

Fig. 3 is the excitation spectrum of Ca _1.9998 Eu _0.0002 NbO ₆ F prepared according to the technical scheme of Example 1 of the present invention under 440 nm light monitoring.

Fig. 4 is a luminescence spectrum diagram of Ca _1.9998 Eu _0.0002 NbO ₆ F prepared according to the technical scheme of Example 1 of the present invention under 310 nm light excitation.

Fig. 5 is an attenuation curve of Ca _1.9998 Eu _0.0002 NbO ₆ F prepared according to the technical scheme of Example 2 of the present invention at an excitation wavelength of 310 nm and a monitoring wavelength of 440 nm.

Fig. 6 is an X-ray powder diffraction pattern of Ca _1.998 Eu _0.002 NbO ₆ F prepared according to the technical scheme of Example 2 of the present invention.

Fig. 7 is an SEM image of Ca _1.998 Eu _0.002 NbO ₆ F prepared according to the technical scheme of Example 2 of the present invention.

Fig. 8 is the excitation spectrum of Ca _1.998 Eu _0.002 NbO ₆ F prepared according to the technical solution of Example 2 of the present invention under 430 nm light monitoring.

Fig. 9 is a luminescence spectrum diagram of Ca _1.998 Eu _0.002 NbO ₆ F prepared according to the technical scheme of Example 2 of the present invention under 270 nm light excitation.

Fig. 10 is an attenuation curve of Ca _1.998 Eu _0.002 NbO ₆ F prepared according to the technical solution of Example 2 of the present invention when the excitation wavelength is 270 nm and the monitoring wavelength is 430 nm.

detailed description

The technical solutions of the present invention will be further described below in conjunction with the accompanying drawings and embodiments.

Example 1:

Preparation of Ca _1.9998 Eu _0.0002 NbO ₆ F

According to the chemical formula Ca _1.9998 Eu _0.0002 NbO ₆ F, niobium pentoxide Nb ₂ O ₅ : 1.33 grams and europium oxide Eu ₂ O ₃ : 0.0004 grams were weighed respectively. After grinding niobium pentoxide Nb ₂ O ₅ and europium oxide Eu ₂ O ₃ in an agate mortar and mixing them evenly, select the air atmosphere for the first calcination at a temperature of 350°C for 3 hours, and then cool to room temperature. Take out the sample; fully mix and grind the raw materials calcined for the first time, and sinter again in the air atmosphere at a temperature of 600°C for 8 hours, then cool to room temperature, and take out the sample; then weigh calcium fluoride CaF ₂ : 1.56 gram, added to the obtained mixture, put it in a muffle furnace after being fully ground again, and calcined under a carbon powder reducing atmosphere, the calcining temperature is 850°C, and the calcining time is 10 hours, and the powdered fluorate blue color is obtained. Luminescent material.

Referring to accompanying drawing 1, it is the X-ray powder diffraction spectrum of the sample prepared according to the technical scheme of embodiment 1 of the present invention, XRD test result shows, the prepared material is fluoride Ca _1.9998 Eu _0.0002 NbO ₆ F is a single-phase material, without Any other impurity phases are present.

Referring to accompanying drawing 2, it is the SEM picture of the material sample prepared according to the technical scheme of embodiment 1 of the present invention, and this material crystallization performance is good, and particle size is relatively uniform, and average particle size is 20 microns.

Referring to accompanying drawing 3, it is the excitation spectrum obtained by preparing the sample according to the technical scheme of Example 1 of the present invention and monitoring the emitted light at 440 nanometers. In the ultraviolet region, fluorescent lamps excited by ultraviolet light can be prepared well.

Referring to accompanying drawing 4, it is the luminescence spectrogram that prepares the sample according to the technical scheme of embodiment 1 of the present invention and obtains with ultraviolet light 310 nanometers excitation, and the main center luminescence wavelength of this material is the blue luminescence band of 440 nanometers, calculates by CIE at the same time, It is known that its coordinates are x=0.171, y=0.026, which also happens to fall in the blue area.

Referring to accompanying drawing 5, it is the luminescence attenuation curve of the material sample prepared according to the technical scheme of this example at an excitation wavelength of 310 nanometers and a monitoring wavelength of 440 nanometers. From the figure, it can be calculated that the attenuation time of the blue phosphor is 2.853 microseconds.

Example 2:

Preparation of Ca _1.998 Eu _0.002 NbO ₆ F

According to the chemical formula Ca _1.998 Eu _0.002 NbO ₆ F, calcium carbonate CaCO ₃ : 2.00 grams and niobium pentoxide Nb ₂ O ₅ : 1.33 grams were weighed respectively. After grinding calcium carbonate CaCO ₃ and niobium pentoxide Nb ₂ O ₅ in an agate mortar and mixing them evenly, select the air atmosphere for the first calcination, the temperature is 380°C, the calcination time is 4 hours, then cool to room temperature, and take out the sample ; The raw materials calcined for the first time were fully mixed and ground again, and then sintered again in an air atmosphere at a temperature of 500°C and a calcination time of ₅ hours, then cooled to room temperature, and the sample was taken out; Add it to the obtained mixture, put it in a muffle furnace after fully grinding again, and carry out calcination under a carbon powder reducing atmosphere. The calcination temperature is 600°C, and the calcination time is 5 hours, and the powdery fluorate blue luminescent material is obtained .

Referring to accompanying drawing 6, it is the X-ray powder diffraction spectrum of sample prepared according to the technical scheme of embodiment 2 of the present invention, and XRD test result shows, the prepared material is fluoride Ca _1.998 Eu _0.002 NbO ₆ F is a single-phase material, without Any other impurity phases are present.

Referring to accompanying drawing 7, it is the SEM image of the material sample prepared according to the technical solution of Example 2 of the present invention, the material has good crystallization performance, relatively uniform particle size, and the average particle size is 15 microns.

Referring to accompanying drawing 8, it is the excitation spectrum obtained by preparing the sample according to the technical scheme of Example 2 of the present invention and monitoring the emitted light at 430 nanometers. In the ultraviolet region, fluorescent lamps excited by ultraviolet light can be prepared well.

Referring to accompanying drawing 9, it is the luminescence spectrogram that the sample prepared according to the technical scheme of embodiment 2 of the present invention is excited by ultraviolet light at 270 nanometers. At the same time, it is calculated by CIE that its coordinates are x=0.154, y=0.036, which is just right fall in the blue area.

Referring to accompanying drawing 10, it is the luminescence attenuation curve of the material sample prepared according to the technical scheme of this example at the excitation wavelength of 270 nanometers and the monitoring wavelength of 430 nanometers. From the figure, it can be calculated that the attenuation time of the blue phosphor is 11.35 microseconds.

Example 3:

Preparation of Ca _1.99 Eu _0.01 NbO ₆ F

According to the chemical formula Ca _1.99 Eu _0.01 NbO ₆ F, calcium oxide CaO: 1.12 grams, europium nitrate Eu(NO ₃ ) ₃ ·6H ₂ O: 0.045 grams were weighed respectively. Grind calcium oxide CaO and europium nitrate Eu(NO ₃ ) ₃ ·6H ₂ O in an agate mortar and mix them evenly, then select the air atmosphere for the first calcination, the temperature is 400°C, the calcination time is 4 hours, and then cooled to room temperature , take out the sample; fully mix and grind the raw materials calcined for the first time, and sinter again in the air atmosphere, the temperature is 450 ° C, the calcination time is 6 hours, and then cooled to room temperature, take out the sample; then weigh niobium pentafluoride NbF ₅ : 1.88 g, added to the obtained mixture, fully ground again, placed in a muffle furnace, and calcined under a carbon powder reducing atmosphere, the calcining temperature was 650 ° C, and the calcining time was 6 hours, and the powdery fluoride salt was obtained Blue luminescent material. Its main structural properties, excitation spectrum, luminescence spectrum, and decay curve are similar to those of Example 1.

Example 4:

Preparation of Ca _1.98 Eu _0.02 NbO ₆ F

According to the chemical formula Ca _1.98 Eu _0.02 NbO ₆ F, weigh calcium hydroxide Ca(OH) ₂ : 1.47 grams, and europium oxide Eu ₂ O ₃ : 0.036 grams. After grinding calcium hydroxide Ca(OH) ₂ and europium oxide Eu ₂ O ₃ in an agate mortar and mixing them evenly, select the air atmosphere for the first calcination, the temperature is 450°C, the calcination time is 5 hours, and then cooled to room temperature, Take out the sample; fully mix and grind the raw materials calcined for the first time, and sinter again in the air atmosphere at a temperature of 500°C for 6 hours, then cool to room temperature, and take out the sample; then weigh niobium tetrafluoride NbF ₄ : 1.69 grams, added to the obtained mixture, fully ground again, placed in a muffle furnace, and calcined in a carbon powder reducing atmosphere, the calcining temperature is 700 ° C, and the calcining time is 7 hours, and the powdered fluorate blue is obtained color luminescent material. Its main structural properties, excitation spectrum, luminescence spectrum, and decay curve are similar to those of Example 1.

Example 5:

Preparation of Ca _1.9 Eu _0.1 NbO ₆ F

According to the chemical formula Ca _1.9 Eu _0.1 NbO ₆ F, weigh calcium bicarbonate Ca (HCO ₃ ) ₂ : 3.07 grams, and niobium pentoxide Nb ₂ O ₅ : 1.33 grams. Calcium bicarbonate Ca(HCO ₃ ) ₂ and niobium pentoxide Nb ₂ O ₅ were ground and mixed uniformly in an agate mortar, and then calcined for the first time in an air atmosphere at a temperature of 500°C for 6 hours and then cooled to room temperature, take out the sample; fully mix and grind the raw materials calcined for the first time, and sinter again in the air atmosphere, the temperature is 550 ° C, and the calcination time is 7 hours, then cool to room temperature, take out the sample; then weigh europium fluoride EuF ₃ : 0.21 g, added to the obtained mixture, fully ground again, placed in a muffle furnace, and calcined under a carbon powder reducing atmosphere, the calcining temperature is 700 ° C, and the calcining time is 7 hours, and the powdery hydrofluoric acid is obtained Salt blue luminescent material. Its main structural properties, excitation spectrum, luminescence spectrum, and decay curve are similar to those of Example 1.

Embodiment 6:

Preparation of Ca _1.84 Eu _0.16 NbO ₆ F

According to the chemical formula Ca _1.84 Eu _0.16 NbO ₆ F, respectively weigh niobium hydroxide Nb(OH) ₅ : 1.78 g, and europium oxide Eu ₂ O ₃ : 0.29 g. After grinding niobium hydroxide Nb(OH) ₅ and europium oxide Eu ₂ O ₃ in an agate mortar and mixing them evenly, select the air atmosphere for the first calcination, the temperature is 550°C, the calcination time is 6 hours, and then cooled to room temperature, Take out the sample; fully mix and grind the raw materials calcined for the first time, and sinter again in the air atmosphere at a temperature of 600°C for 8 hours, then cool to room temperature, and take out the sample; then weigh calcium fluoride CaF ₂ : 1.44 grams, added to the obtained mixture, put it in a muffle furnace after fully grinding again, and calcined in a carbon powder reducing atmosphere, the calcining temperature is 750 ° C, and the calcining time is 8 hours, and the powdered fluorate blue color is obtained. Luminescent material. Its main structural properties, excitation spectrum, luminescence spectrum, and decay curve are similar to those of Example 2.

Embodiment 7:

Preparation of Ca _1.8 Eu _0.2 NbO ₆ F

According to the chemical formula Ca _1.8 Eu _0.2 NbO ₆ F, weigh calcium nitrate Ca(NO ₃ ) ₂ : 2.96 grams, and europium oxide Eu ₂ O ₃ : 0.29 grams. After grinding calcium nitrate Ca(NO ₃ ) ₂ and europium oxide Eu ₂ O ₃ in an agate mortar and mixing them evenly, select the air atmosphere for the first calcination, the temperature is 350°C, the calcination time is 6 hours, and then cooled to room temperature, Take out the sample; fully mix and grind the raw materials calcined for the first time, and sinter again in the air atmosphere at a temperature of 500°C for 6 hours, then cool to room temperature, and take out the sample; then weigh niobium tetrafluoride NbF ₄ : 1.69 g, added to the obtained mixture, fully ground again, placed in a muffle furnace, and calcined under a carbon powder reducing atmosphere, the calcining temperature was 800 ° C, and the calcining time was 8 hours, and the powdered fluorate blue was obtained color luminescent material. Its main structural properties, excitation spectrum, luminescence spectrum, and decay curve are similar to those of Example 2.

Embodiment 8:

Preparation of Ca _1.7 Eu _0.3 NbO ₆ F

According to the chemical formula Ca _1.7 Eu _0.3 NbO ₆ F, niobium dioxide NbO ₂ : 2.50 grams and europium oxide Eu ₂ O ₃ : 0.53 grams were weighed respectively. After grinding niobium dioxide NbO ₂ and europium oxide Eu ₂ O ₃ in an agate mortar and mixing them evenly, select the air atmosphere for the first calcination, the temperature is 400°C, the calcination time is 6 hours, then cool to room temperature, and take out the sample; The raw materials calcined for the first time were fully mixed and ground evenly, and then sintered again in air atmosphere at a temperature of 550°C and a calcination time of 7 hours, then cooled to room temperature, and the sample was taken out; then weighed calcium tetrafluoride CaF ₂ : 1.33 grams, Add it to the obtained mixture, grind it thoroughly again, place it in a muffle furnace, and calcine it in a carbon powder reducing atmosphere. The calcination temperature is 850°C, and the calcination time is 10 hours. . Its main structural properties, excitation spectrum, luminescence spectrum, and decay curve are similar to those of Example 2.

Claims (7)

1. an Eu²⁺The fluorate based luminescent material of doping, it is characterised in that: chemical formula is Ca_2-2xEu_2xNbO₆F, wherein x is Eu²⁺Doping substitutes Ca²⁺Mole percent, span is 0.0001≤x≤0.15；This fluorescent material, under the ultraviolet excitation that wavelength is 270 nanometers, launches the wavelength blue-fluorescence in 400-480 nano-area。

2. an Eu²⁺The preparation method of the fluorate based luminescent material of doping, it is characterised in that adopt high temperature solid-state method, comprise the following steps:

According to formula Ca_2-2xEu_2xNbO₆In F, the stoichiometric proportion of corresponding element weighs raw material, the compound of calcium ions, the compound containing europium ion and the compound containing niobium ion, grinds and makes mix homogeneously, and wherein, x is Eu²⁺Replace Ca²⁺Molar percentage coefficient, 0.0001≤x≤0.15；

Being calcined in air atmosphere by mixture, calcining heat is 300～650 DEG C, and calcination time is 2～10 hours, repeats this step 2 times；

By the mixture natural cooling after calcining, grinding and mix homogeneously, calcine under carbon reducing agent atmosphere, calcining heat is 650～900 DEG C, and calcination time is 5～12 hours, obtains a kind of fluorate blue colour fluorescent powder。

3. a kind of Eu according to claim 2²⁺The fluorate based luminescent material preparation method of doping, it is characterised in that: the compound of described calcium ions is the one in calcium carbonate, calcium bicarbonate, calcium hydroxide, calcium nitrate, calcium oxide, calcium fluoride。

4. a kind of Eu according to claim 2²⁺The preparation method of the fluorate based luminescent material of doping, it is characterised in that: the described compound containing europium ion is the one in europium oxide, europium nitrate, europium。

5. a kind of Eu according to claim 2²⁺The preparation method of the fluorate based luminescent material of doping, it is characterised in that: the described compound containing niobium ion includes the one in niobium pentaoxide, columbium dioxide, niobium hydroxide, tetrafluoride niobium, Columbium pentafluoride.。

6. a kind of Eu according to claim 2²⁺The preparation method of the fluorate based luminescent material of doping, it is characterised in that: the calcining heat described in step (2) is 350～600 DEG C, and calcination time is 3～8 hours；Calcining heat described in step (3) is 600～850 DEG C, and calcination time is 5～10 hours。

7. an Eu²⁺The application of fluorate based luminescent material of doping, it is characterised in that: be applied to ultraviolet light be excitaton source various illumination displays and luminescence generated by light colourity regulate。