CN110184057A - A kind of oxygen fluoride red fluorescence powder and preparation method thereof - Google Patents

Abstract

The invention relates to an oxyfluoride red fluorescent powder and a preparation method thereof, the molecular formula of which is KNaMO ₂ F ₄ :Mn ⁴⁺ , wherein M=Mo or W. The preparation process includes the following steps: S1: Dissolving KF and Na ₂ MO ₄ ·2H ₂ O (M=W, Mo) in HF solution and stirring evenly; S2: Adding K ₂ MnF ₆ to make the molar feeding of each material The ratio satisfies (Na ₂ WO ₄ ·2H ₂ O+Na ₂ MoO ₄ ·2H ₂ O):K ₂ MnF ₆ :HF=1:1:(0.005～0.05):16, stir well; S3: add precipitant, After stirring and centrifuging, the obtained precipitate is washed, and finally dried to obtain a red fluorescent powder product. Compared with the prior art, the present invention synthesizes a brand-new Mn ⁴⁺ ion-doped oxyfluoride system red phosphor, which has the characteristics of good luminous position and high luminous intensity. Compared with the existing fluoride phosphor powder doped with Mn ⁴⁺ ions, the phosphor powder of the present invention has the advantage of being more stable in physicochemistry.

Description

A kind of oxyfluoride red fluorescent powder and preparation method thereof

technical field

The invention relates to the technical field of fluorescent powder, in particular to an oxyfluoride red fluorescent powder and a preparation method thereof.

Background technique

White light LED is a new type of solid-state lighting source. Compared with traditional incandescent lamps and fluorescent lamps, it has significant advantages such as low power consumption, high efficiency, green environmental protection, energy saving, long life, small size, fast response, and good color rendering. The new generation of green and environment-friendly lighting sources has broad market prospects and huge social and economic benefits, and has received widespread attention from the industry.

The current mass production of commercial white LEDs is mainly realized by the combination of InGaN blue chips and YAG:Ce ³⁺ yellow phosphors. However, due to the lack of red components, the high color temperature and low color rendering index of white light inevitably limit the Applications in indoor lighting. Therefore, it becomes a trend to research a kind of red phosphor that can be used in LED.

At present, Eu ²⁺ doped nitride phosphors (such as: CaAlSiN ₃ :Eu ²⁺ ) have attracted more and more attention due to their high efficiency and high stability, and have been commercialized. However, due to its severe reabsorption phenomenon and high synthesis cost, researchers have turned more attention to non-rare earth Mn ⁴⁺ doped red phosphors. This method not only has low synthesis cost, but also has an ideal spectrum. nature. As a transition metal ion, Mn ⁴⁺ has an unfilled 3d ³ electron shell. Due to the obvious electronic configuration of Mn ⁴⁺ , all substances doped with Mn ⁴⁺ exhibit wide excitation bands and narrow emission bands. Mn ⁴⁺ -doped oxide red phosphors, although they have excellent thermal and chemical stability and simple preparation process, most of the photoluminescence (PL) spectrum exceeds the sensitivity of human eyes, and low red purity It hinders their application in LED background light source.

Contents of the invention

The object of the present invention is to provide an oxyfluoride red phosphor and a preparation method thereof in order to overcome the defects of the above-mentioned prior art.

The purpose of the present invention can be achieved through the following technical solutions:

An oxyfluoride red phosphor, said oxyfluoride red phosphor is Mn ⁴⁺ doped oxyfluoride, its molecular formula is KNaMO ₂ F ₄ :Mn ⁴⁺ , wherein M=Mo or W.

Further, the Mn ⁴⁺ doping ions in the Mn ⁴⁺ doped oxyfluoride occupy the positions of the Mo ^{6 +} and W ⁶⁺ lattices in the oxide matrix lattice.

Further, the Mn ⁴⁺ coordinates with oxygen ions and fluorine ions simultaneously to form [MO ₂ F ₄ ] octahedra.

A preparation method of oxyfluoride red fluorescent powder, comprising the following steps:

S1: Dissolve KF and Na ₂ MO ₄ ·2H ₂ O (M=W, Mo) in HF solution and stir evenly;

S2: Add K ₂ MnF ₆ , so that the molar feed ratio of each material satisfies (Na ₂ WO ₄ ·2H ₂ O+Na ₂ MoO ₄ ·2H ₂ O):K ₂ MnF ₆ :HF=1:1:(0.005 ~0.05):16, stir evenly;

S3: adding a precipitating agent, stirring, centrifuging, washing the obtained precipitate, and finally drying to obtain a red fluorescent powder product.

Further, the mass concentration of the HF solution in the S1 process is 40%-50%.

Further, the preparation method of K ₂ MnF ₆ used in the S2 process is: dissolving KHF ₂ in 40% by mass HF, stirring until colorless, adding KMnO ₄ , then stirring in an ice bath for 20 min, adding dropwise With 30% mass concentration of H ₂ O ₂ , the color of the solution changed from purple-black to brown-yellow. The precipitate was obtained by centrifugation. The precipitate was washed three times with acetone and dried to obtain K ₂ MnF ₆ .

Further, the precipitation agent used in the S3 process is ethanol or methanol.

Further, the drying process in the S3 process is vacuum drying at 60° C., and the drying time is 3 hours.

In the crystal field where both F- and ^{O2- exist, the double-ligand coordination of F- and O2- distorts the} octahedron severely and induces some excellent spectral changes. Doping Mn ⁴⁺ in oxyfluorides is an effective strategy to develop new red phosphors with satisfactory spectral characteristics at low cost.

The invention proposes a novel Mn ⁴⁺ activated oxyfluoride fluorescent powder and a preparation method thereof. The general chemical formula of the fluorescent powder in the present invention is KNaMO ₂ F ₄ :Mn ⁴⁺ (M=Mo, W). In these host compounds, Mn ⁴⁺ dopant ions occupy the positions of Mo ⁶⁺ and W ⁶⁺ lattices in the host lattice, in which Mn ⁴⁺ coordinates with oxygen ions and fluorine ions at the same time to form [MnO ₂ F ₄ ]8 surface body. The red fluorescent powder in the present invention can emit red light with a central peak at 632 nm under the excitation of 475 nm blue light.

Compared with the prior art, the present invention has the following advantages:

1) In the present invention, a brand-new Mn ⁴⁺ ion-doped oxyfluoride system red phosphor is synthesized by coprecipitation method.

2) The oxyfluoride phosphor powder of the present invention has the characteristics of good luminous position and high luminous intensity. Compared with the Mn ⁴⁺ ion-doped fluoride phosphor, the phosphor of the present invention has the advantage of being more stable in physicochemistry, and compared with the reported Mn ⁴⁺ doped oxide red phosphor, the phosphor of the present invention has luminescence Good location and high luminous efficiency.

Description of drawings

Fig. 1 is the photoinduced excitation and emission spectrum of KNaMO ₂ F ₄ :Mn ⁴⁺ (M=Mo, W) phosphor;

FIG. 2 is an X-ray diffraction pattern of KNaWO ₂ F ₄ :Mn ⁴⁺ red phosphor powder in Example 1.

Detailed ways

The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

Example 1:

Add 0.23g KF and 1.319g Na ₂ WO ₄ ·2H ₂ O into 2mL HF and react for 10min. Then add 0.0049g K ₂ MnF ₆ , react for 20min, and add 3mL of methanol. Centrifuge (4000/min), wash with ethanol to pH = 7, collect the precipitate, and vacuum dry at 60° C. for 3 hours to obtain oxyfluoride red phosphor.

The preparation method of _K2MnF6 used is: weigh 18g _KHF2 and dissolve in 60mL _HF ( ₄₀ %), stir until colorless, add 0.9g KMnO4 and stir for 10min, then stir in ice bath for 20min, dropwise After adding 1.5mL H ₂ O ₂ (30%), the color of the solution changed from purple-black to brown-yellow. The precipitate was obtained by centrifugation, washed 3 times with acetone, and dried at 70°C for 3 hours to obtain yellow powder K ₂ MnF ₆ .

X-ray structure analysis shows that the obtained luminescent material is KNaWO ₂ F ₄ (as shown in Figure 2). Using a fluorescence spectrometer (HITACHI F-7000) to test the spectral properties of the fluorescent powder in this system, the results show that there is a strong blue light absorption, and the sample emits bright red light under the excitation of 475nm blue light, and the emission spectrum is characterized by a narrow-band line. The strong peak is located at 632nm, and the emission band covers 600-650nm (as shown by the solid line in Figure 1).

Example 2:

Add 0.291g KF and 1.210g Na ₂ MoO ₄ ·2H ₂ O into 2mL HF and react for 10min. Then add 0.0062g K ₂ MnF ₆ , react for 20min, and add 3mL of methanol. Centrifuge (4000/min), wash with ethanol to pH = 7, collect the precipitate, and vacuum dry at 60° C. for 3 hours to obtain oxyfluoride red phosphor.

Using a fluorescence spectrometer (HITACHI F-7000) to test the spectral properties of the fluorescent powder in this system, the results show that there is a strong blue light absorption, and the sample emits bright red light under the excitation of 475nm blue light, and the emission spectrum is characterized by a narrow-band line. The strong peak is located at 632nm, and the emission band covers 600-650nm (as shown by the dotted line in Figure 1).

The above descriptions of the embodiments are for those of ordinary skill in the art to understand and use the invention. It is obvious that those skilled in the art can easily make various modifications to these embodiments, and apply the general principles described here to other embodiments without creative effort. Therefore, the present invention is not limited to the above-mentioned embodiments. Improvements and modifications made by those skilled in the art according to the disclosure of the present invention without departing from the scope of the present invention should fall within the protection scope of the present invention.

Claims (8)

1. a kind of oxygen fluoride red fluorescence powder, which is characterized in that the oxygen fluoride red fluorescence powder is Mn⁴⁺The oxygen of doping Fluoride, molecular formula KNaMO₂F₄:Mn⁴⁺, wherein M=Mo or W.

2. a kind of oxygen fluoride red fluorescence powder according to claim 1, which is characterized in that the Mn⁴⁺The oxygen of doping Mn in fluoride⁴⁺Doped ions occupy Mo in matrix of oxide lattice⁶⁺Or W⁶⁺Lattice position.

3. a kind of oxygen fluoride red fluorescence powder according to claim 1, which is characterized in that the Mn⁴⁺While and oxygen Ion and coordinating fluoride form [MnO₂F₄] octahedra.

4. the preparation method of oxygen fluoride red fluorescence powder in a kind of claim 1, which comprises the following steps:

S1: by KF and Na₂MO₄·2H₂O (M=W, Mo) is dissolved in HF solution, is stirred evenly；

S2: K is added₂MnF₆, so that wherein the molar feed ratio of each material meets (Na₂WO₄·2H₂O+Na₂MoO₄·2H₂O): K₂MnF₆: HF=1:1:(0.005~0.05): 16, it stirs evenly；

S3: being added precipitating reagent, and stirring washs obtained sediment after centrifugation, obtains red fluorescence powder after finally drying Product.

5. a kind of preparation method of oxygen fluoride red fluorescence powder according to claim 4, which is characterized in that during S1 The mass concentration of HF solution is 40%~50%.

6. a kind of preparation method of oxygen fluoride red fluorescence powder according to claim 4, which is characterized in that during S2 Used K₂MnF₆The preparation method comprises the following steps: by KHF₂It is dissolved in the HF of 40% mass, stirring to colourless, addition KMnO₄, so 20min is stirred in ice bath afterwards, the H of 30% mass concentration is added dropwise₂O₂, solution colour becomes brown color from atropurpureus, is centrifuged It is precipitated, precipitating is used acetone washing 3 times, obtain K after dry₂MnF₆。

7. a kind of preparation method of oxygen fluoride red fluorescence powder according to claim 4, which is characterized in that during S3 Used precipitating reagent is ethyl alcohol or methanol.

8. a kind of preparation method of oxygen fluoride red fluorescence powder according to claim 4, which is characterized in that during S3 Drying process be 60 DEG C under the conditions of vacuum drying, drying time 3h.