CN108359461B - A kind of deep red bimodal emission titanium-germanate nano-phosphor and preparation method thereof - Google Patents

Abstract

The invention relates to a deep red double-peak emitting titanium germanate nano fluorescent powder. TheThe chemical formula of the phosphor is M_2wMg_{2‑ w}Ti_1‑x‑yGe_yO₄：xMn⁴⁺Wherein 0 is<x<0.05，0<y<0.7, 0-1, M is alkali metal element, or N_zMg_2‑zTi_{1‑x‑ y}Ge_yO₄：xMn⁴⁺Wherein 0 is<x<0.05，0<y<Z is more than 0.7 and less than or equal to 0.2, and N is an alkaline earth metal element. The fluorescent powder has the advantages of high red color gamut, high luminous efficiency, low color temperature, low cost and the like.

Description

A kind of deep red bimodal emission titanium-germanate nano-phosphor and preparation method thereof

technical field

The invention relates to a luminescent material, in particular to a deep red double-peak emission titanium-germanate nano-phosphor and a preparation method thereof.

Background technique

At present, white LED, as a new type of green solid-state lighting source, is widely used in the backlight of mobile phones and liquid crystal displays due to its advantages of energy saving, environmental protection, small size, low calorific value, low power consumption, long life and fast response. , indicator lights, outdoor lighting, indoor lighting, landscape lighting, billboards, traffic lights, etc., have set off a white LED boom in the global semiconductor and lighting fields. Existing white light LEDs mainly utilize the emitted light of light emitting diodes (LEDs) to excite phosphors to achieve white light emission. There are three main ways to realize white light LED: one is to combine a blue light chip and a yellow phosphor that can be effectively excited by blue light to form a white light LED, which is currently a mainstream technical solution to realize white light LED, but lacks red light components; two It is to use ultraviolet chips and phosphors that can be effectively excited by ultraviolet light to emit red, green, and blue primary colors to form white LEDs; the third is to assemble red, green, and blue LED chips to achieve white light. However, there is a shortage of phosphors that can be effectively excited by near-ultraviolet light and blue light, especially the lack of high-efficiency red phosphors, resulting in a low color rendering index and a high color temperature of white LEDs, which affects the popularization and application of LEDs.

In recent years, people have begun to try to use blue LED chips plus green and red phosphors or InGaN chips with near-ultraviolet-ultraviolet (350-410 nm) emission to excite three-primary phosphors to realize white LEDs. color temperature white LEDs. Nichia Corporation of Japan has a pioneering invention in this field (US5998925A). The blue GaN chip excites YAG yellow phosphor to obtain white light. The system has high luminous efficiency, but due to the lack of red light in the spectral composition, the color temperature is high and the color rendering is high. Poor sex. Chinese Patent No. 201110157772.2 discloses a nitrogen oxide phosphor, which can manufacture white LEDs with high color rendering and low color temperature. However, the luminous efficiency of nitrogen oxide phosphors is low, and the preparation method requires high temperature and high pressure. At present, there are still great limitations as a white light LED material. In addition, most of the red light emitted by the existing red phosphors has poor color rendering and is not close to the real red, and is yellowish. Therefore, it is very important to study new red phosphors for LEDs.

SUMMARY OF THE INVENTION

The first object of the present invention is to provide a deep red bimodal emitting titanium-germanate nano-phosphor, which has many advantages, such as high red color gamut, high luminous efficiency, low color temperature, and low cost.

Another object of the present invention is to provide a method for preparing the above-mentioned deep red bimodal emission titanium-germanate nano-phosphor.

The purpose of this invention is to realize through the following technical solutions:

A deep red bimodal emission titanium-germanate nano-phosphor, characterized in that: the chemical formula of the phosphor is M _2w Mg _2-w Ti _1-xy Ge _y O ₄ : xMn ⁴⁺ , wherein 0<x< 0.05, 0<y<0.7, 0≤w≤1, M is an alkali metal element, or N _z Mg _2-z Ti _1-xy Ge _y O ₄ : xMn ⁴⁺ , where 0<x<0.05, 0<y<0.7,0<z≤0.2, N is an alkaline earth metal element.

When the alkali metal element M or the alkaline earth metal element N in the chemical formula of the phosphor powder are selected as different metal elements, the final product phosphor powder prepared has no difference in morphology and luminescence effect, and the difference is only in the luminescence range. Different adjustments, but the double emission peaks are in the two numerical ranges of 630nm±10nm and 660nm±10nm respectively.

The preparation method of the above-mentioned deep red double-peak emission titanium-germanate nano-phosphor comprises the following steps:

(1) According to the stoichiometric ratio of each element in the chemical formula, weigh the corresponding titanium oxide, germanium oxide and manganese carbonate, magnesium oxide or magnesium carbonate, and metal salts containing M element or N element;

2) Mix titanium oxide, germanium oxide and manganese carbonate, magnesium oxide or magnesium carbonate, and metal salts containing M element or N element and grind, add lubricant during the grinding process, and the amount of lubricant added is kept dispersed by the grinding system It is limited until the reactant and the ligand are completely reacted to obtain the precursor powder;

3) calcining the precursor powder in an air atmosphere to obtain the target product.

As further clarification, the calcination temperature in the above step 3) is 1300°C to 1500°C, and the calcination time is 3 to 6 hours.

As further clarification, the above-mentioned metal salt containing M element or N element can be selected from carbonate, nitrate and chloride of alkali metal element or alkaline earth metal element.

To be more specific, the above-mentioned lubricant is ethanol or ethylene glycol.

As a further clarification, the above grinding was performed at room temperature.

Compared with the prior art, the present invention has the following beneficial effects:

The invention provides a deep red double-peak emission titanium-germanate nano-fluorescent powder, the fluorescent powder has double emission peaks (the double emission peaks are respectively 630nm±10nm, 660nm±10nm), and the luminescence is more diverse; its matrix It is titanium germanate, the luminescent center is Mn ⁴⁺ , and the raw material composition does not contain rare earth ions, so the cost is low; its crystallinity is good, the particles are fine, the particle surface is smooth, and the distribution is uniform; it has good luminescence characteristics and high red color gamut , high color display, true color rendering, color coordinate value (0.7147, 0.2853), close to standard red light; the phosphor can effectively absorb the excitation wavelength in the range of 200-500nm, suitable for vacuum ultraviolet and ultraviolet excitation red Phosphor powder, with high luminous efficiency and good stability, its thermal quenching temperature (the temperature when the emission spectrum intensity is 50% of normal temperature) is greater than 200°C, the emission spectrum intensity at 150°C is greater than 85% of normal temperature, and it emits light at 250°C The efficiency is 80% at room temperature; the deep red light it emits has a low color temperature and is less harmful to the eyes. In addition, the method of the present invention adopts the calcination method to prepare the above-mentioned fluorescent powder, which has the advantages of simple process, easy operation, low cost, good repeatability, etc., and is easy to be industrialized.

Description of drawings

Fig. 1 is the XRD spectrum of the deep red bimodal emission titanium-germanate nano-phosphor described in Example 1 of the present invention;

Fig. 2 is the SEM image of the deep red bimodal emission titanium-germanate nano-phosphor described in Example 1 of the present invention;

Fig. 3 is the excitation spectrogram of the deep red double-peak emission titanium-germanate nano-phosphor described in Example 1 of the present invention when the monitoring wavelength is 661 nm and the emission spectrogram under the excitation wavelength of 300 nm;

4 is a color coordinate diagram of the deep red bimodal emitting titanium-germanate nano-phosphor in Example 1 of the present invention.

FIG. 5 is a thermal stability test diagram of the deep red bimodal emitting titanium-germanate nano-phosphor in Example 1 of the present invention.

Detailed ways

The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

Example 1

A preparation method of a deep red double-peak emission titanium-germanate nano-phosphor, comprising the following steps:

(1) According to the stoichiometric ratio of each element in the chemical formula of Mg ₂ Ti _0.699 Ge _0.3 O ₄ : 0.001Mn ⁴⁺ , weigh the corresponding magnesium carbonate, titanium oxide, germanium oxide, and manganese carbonate;

2) Grind magnesium carbonate, titanium oxide, germanium oxide and manganese carbonate at room temperature, add ethanol during the grinding process, and the amount of ethanol added is limited to the dispersion of the grinding system until the reactant and the ligand are completely reacted to obtain the precursor. powder;

3) The precursor powder is calcined in an air atmosphere, the calcination temperature is 1400°C, and the calcination time is 6 hours, and the target product is obtained.

The XRD spectrum, SEM image, color coordinate diagram, thermal stability test diagram of the deep red double-peak emission titanium-germanate nano-phosphor prepared in this example, as well as its excitation spectrum and excitation wavelength at the monitoring wavelength of 661 nm is the emission spectrum of 300nm, as shown in Figures 1, 2, 4, 5 and 3 respectively; it can be seen that the phosphor has dual emission peaks at 630nm and 660nm, and the luminescence is more diverse; its particles are fine, the particle surface is smooth, and the distribution Uniform; high luminous efficiency and good stability, the luminous efficiency at 250°C is 80% of that at room temperature, and the emission spectrum intensity at 150°C is greater than 85% of normal temperature; it has good luminous properties, high red color gamut, and high color display. , the color rendering is true, the color coordinate value is (0.7147, 0.2853), and the color is close to the standard red light.

Example 2

A preparation method of a deep red double-peak emission titanium-germanate nano-phosphor, comprising the following steps:

(1) According to the stoichiometric ratio of each element in the chemical formula of Mg _1.99 Ba _0.01 Ti _0.699 Ge _0.3 O ₄ : 0.001Mn ⁴⁺ , weigh the corresponding barium carbonate, magnesium oxide, titanium oxide, germanium oxide, and manganese carbonate;

2) Grind barium carbonate, magnesium oxide, titanium oxide, germanium oxide and manganese carbonate at room temperature, add ethylene glycol during the grinding process, and the amount of ethylene glycol added is limited to the dispersion of the grinding system until the reactants and ligands Until the reaction is complete, the precursor powder is obtained;

3) The precursor powder is calcined in an air atmosphere, the calcination temperature is 1300° C., and the calcination time is 5.5 hours, and the target product is obtained.

Example 3

A preparation method of a deep red double-peak emission titanium-germanate nano-phosphor, comprising the following steps:

(1) According to the stoichiometric ratio of each element in the chemical formula of Na _0.04 Mg _1.98 Ti _0.799 Ge _0.2 O ₄ : 0.001Mn ⁴⁺ , weigh the corresponding sodium carbonate, magnesium carbonate, titanium oxide, germanium oxide, and manganese carbonate;

2) Grind sodium carbonate, magnesium carbonate, titanium oxide, germanium oxide, and manganese carbonate at room temperature, add ethylene glycol during the grinding process, and the amount of ethylene glycol added is limited to the dispersion of the grinding system until the reactants and ligands Until the reaction is complete, the precursor powder is obtained;

3) The precursor powder is calcined in an air atmosphere, the calcination temperature is 1500° C., and the calcination time is 3 hours, and the target product is obtained.

Claims (7)

1. A deep red double-peak emitting titanium germanate nano fluorescent powder is characterized in that: the chemical formula of the fluorescent powder is M_2wMg_2-wTi_1-x-yGe_yO₄：xMn⁴⁺Wherein 0 is<x<0.05，0<y<0.7, 0-1, M is alkali metal element, or N_zMg_{2- z}Ti_1-x-yGe_yO₄：xMn⁴⁺Wherein 0 is<x<0.05，0<y<Z is more than 0 and less than or equal to 0.7 and more than 0 and less than or equal to 0.2, and N is an alkaline earth metal element;

the dual emission peak values of the fluorescent powder are respectively within the ranges of 630nm +/-10 nm and 660nm +/-10 nm.

2. The method for preparing the deep red double-peak emitting titanium germanate nano fluorescent powder according to claim 1, which is characterized by comprising the following steps:

(1) weighing corresponding titanium oxide, germanium oxide, manganese carbonate, magnesium oxide or magnesium carbonate and metal salt containing M element or N element according to the stoichiometric ratio of each element in the chemical formula;

(2) mixing titanium oxide, germanium oxide, manganese carbonate, magnesium oxide or magnesium carbonate and metal salt containing M element or N element, grinding, adding a lubricant in the grinding process, wherein the adding amount of the lubricant is limited by the fact that the ground system keeps dispersing until reactants and ligands completely react to obtain precursor powder;

(3) the precursor powder is calcined under an air atmosphere.

3. The method for preparing the deep red bimodal emission titanium germanate nano fluorescent powder as claimed in claim 2, wherein the method comprises the following steps: the calcination temperature in the step (3) is 1300-1500 ℃, and the calcination time is 3-6 hours.

4. The method for preparing the deep red bimodal emission titanium germanate nano fluorescent powder as claimed in claim 2, wherein the method comprises the following steps: the metal salt containing M element or N element is selected from carbonate, nitrate and chloride of alkali metal element or alkaline earth metal element.

5. The method for preparing the deep red bimodal emission titanium germanate nano fluorescent powder as claimed in claim 2, wherein the method comprises the following steps: the lubricant is ethanol or glycol.

6. The method for preparing the deep red double-peak emitting titanium germanate nano fluorescent powder according to claim 4, wherein the method comprises the following steps: the lubricant is ethanol or glycol.

7. The method for preparing the deep red bimodal emission titanium germanate nano fluorescent powder as claimed in any one of claims 2 to 6, wherein the method comprises the following steps: the milling is carried out at room temperature.

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