CN107541211A - Blue luminescent phosphor suitable near ultraviolet excitation and its preparation method and application - Google Patents

Abstract

The present invention relates to a kind of blue luminescent phosphor suitable near ultraviolet excitation and its preparation method and application, belong to field of light emitting materials.Blue luminescent phosphor provided by the invention suitable near ultraviolet excitation, its formula are：Sr_1‑xM_xLu_2‑yLn_yO₄:Ce³⁺ _m,A_n, wherein M represents one kind or any combination in Mg, Ca and Ba；Ln represents one kind or any combination in Y, La, Gd and Sc；A represents one kind or any combination in Li, Na, K, Rb and Cs；0≤x≤0.5,0≤y≤1,0.0001≤m≤0.01；0≤n≤0.01.The blue-light-emitting effectively excites position to be located at 380 450nm scopes, and emission peak position is located at 445 480nm scopes.The preparation method of the blue luminescent phosphor is simple, pollution-free, cost is low.The blue luminescent phosphor have effectively achieved the light transformation for launching blue light under near ultraviolet excitation.The fluorescent material can be applied to blue light emitting device or device as a kind of blue luminescent phosphor suitable near ultraviolet excitation, can also be mixed with other colour light emitting fluorescent material and be applied to white light emitting device or device.

Description

Blue luminescent phosphor suitable for excitation by near-ultraviolet light, preparation method and application thereof

technical field

The invention belongs to the field of luminescent materials, and in particular relates to a blue luminescent phosphor suitable for excitation by near ultraviolet light, a preparation method and application thereof.

Background technique

White LED (Light Emitting Diode: Light Emitting Diode) has the advantages of high efficiency, energy saving, and long life, and can be widely used in various lighting facilities, such as traffic lights, street lights, car lights, outdoor display screens, and advertising boards. An environmentally friendly, energy-saving green lighting source is a new light source that replaces traditional lighting devices in the 21st century.

At present, the mainstream scheme of white LED lighting is to use blue LED chips to coat yellow phosphor powder, and the yellow light emitted by the yellow phosphor powder and the blue light transmitted by the die are mixed to form white light. However, due to the lack of green and red components in the spectrum, this solution has poor color rendering of the device and is not suitable for indoor lighting, especially places such as galleries, living rooms and exhibition halls. In order to improve the color rendering performance of white LEDs, it has been proposed to use near-ultraviolet LED chips to coat red, green and blue three primary color phosphors, and use the three primary color light emitted by the three primary color phosphors to achieve white light emission, which can improve color rendering. to high above 90. Among them, the development of red, green, and blue three primary color phosphors suitable for near-ultraviolet light excitation is the key.

At present, the industry-recognized blue phosphors suitable for near-ultraviolet light excitation include BaMgAl ₁₀ O ₁₇ :Eu ²⁺ (BAM), Sr ₂ MgSi ₂ O ₇ :Eu ²⁺ and Sr ₅ (PO ₄ ) ₃ Cl:Eu ^{2 +} etc. Recently, Patent No. CN 105219378 B discloses a new type of silicate blue phosphor Na ₂ (Ca _0.5 Sr _0.5-x )(SiO ₄ ):xEu ²⁺ . ^However _{, BAM} ^blue _{powder has poor thermal stability . _ _} The excitation efficiency of ²⁺ drops sharply in the near-ultraviolet region of 400nm. Therefore, new blue phosphors suitable for excitation in the near-ultraviolet region and excellent thermal stability need to be further developed.

Contents of the invention

The purpose of the present invention is to develop a new type of blue light-emitting phosphor suitable for near-ultraviolet light excitation and excellent thermal stability, and further provide a blue light-emitting phosphor suitable for near-ultraviolet light excitation and its preparation method and application.

In order to achieve the above object, the technical solution of the present invention is specifically as follows:

A blue light-emitting phosphor suitable for excitation by near-ultraviolet light, its general formula is: Sr _1-x M _x Lu _2-y Ln _y O ₄ : Ce ³⁺ _m ,A _n , where M represents Mg, Ca and One or any combination of Ba; Ln represents one or any combination of Y, La, Gd and Sc; A represents one or any combination of Li, Na, K, Rb and Cs; 0≤x≤0.5 , 0≤y≤1, 0.0001≤m≤0.01; 0≤n≤0.01.

In the above technical solution, the expression of the blue light-emitting phosphor suitable for excitation by near-ultraviolet light is: SrLu ₂ O ₄ :Ce ³⁺ _0.002 .

A method for preparing a blue light-emitting phosphor suitable for excitation by near-ultraviolet light, comprising the following steps:

1) Weigh each metal element compound in the general formula according to the stoichiometric ratio, fully grind and mix;

The metal element compound is a metal element oxide or a metal element salt compound;

2) Sintering the mixture obtained in step 1) at a temperature of 1500-1650° C. under a reducing atmosphere for 4-8 hours to obtain a sintered body;

3) Grinding the sintered body obtained in step 2), washing, filtering, and drying to obtain a blue light-emitting phosphor suitable for excitation by near-ultraviolet light.

In the above technical solution, in step 2): the reducing atmosphere uses CO or a mixture of _H2 and _N2 as the reducing atmosphere.

In the above technical solution, in step 2): the sintering temperature is 1550-1600° C., and the time is 4 hours.

An application of a blue light-emitting phosphor suitable for excitation by near-ultraviolet light. The blue light-emitting phosphor is used as a light conversion material for a near-ultraviolet LED and is applied to a blue light-emitting device or device.

An application of a blue light-emitting phosphor suitable for excitation by near-ultraviolet light. The blue light-emitting phosphor is mixed with other color light-emitting phosphors and applied to a white light emitting device or device.

In the above technical solution, the other color luminescent phosphors are green and red phosphors suitable for excitation by near-ultraviolet light.

The beneficial effects of the present invention are:

The blue light-emitting fluorescent powder suitable for excitation by near-ultraviolet light provided by the present invention utilizes the 4f-5d energy band structure of rare earth element Ce ³⁺ ions, and can emit peaks in the range of 445-480nm under light excitation in the range of 380-450nm. The blue light emission effectively realizes the photoconversion effect of emitting blue light under the excitation of near-ultraviolet light.

The preparation method of the blue light-emitting fluorescent powder suitable for excitation by near-ultraviolet light provided by the invention is simple, pollution-free and low in cost.

The blue light-emitting phosphor suitable for excitation by near-ultraviolet light provided by the present invention can be used as a light conversion material for near-ultraviolet LEDs to realize blue light-emitting devices or devices, or mixed with other color light-emitting phosphors to realize white light-emitting devices or devices . The phosphor may also have certain applications in fields such as FED (Field Emission Display) and PDP (Plasma Display).

Description of drawings

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

Fig. 1 is the XRD diffraction pattern of Example 1 SrLu ₂ O ₄ :Ce ³⁺ .

Fig. 2 is the emission spectrum (403nm excitation) of SrLu ₂ O ₄ :Ce ³⁺ in Example 1.

Figure 3 is the excitation spectrum (monitored at 458nm) of SrLu ₂ O ₄ :Ce ³⁺ in Example 1.

Fig. 4 is a diagram of temperature-varying intensity of SrLu ₂ O ₄ :Ce ³⁺ in Example 1.

Fig. 5 is an electroluminescent spectrum diagram of a white LED packaged in SrLu ₂ O ₄ :Ce ³⁺ in Example 1.

detailed description

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

A blue light-emitting phosphor suitable for excitation by near-ultraviolet light, its general formula is: Sr _1-x M _x Lu _2-y Ln _y O ₄ : Ce ³⁺ _m ,A _n , where M represents Mg, Ca and One or any combination of Ba; Ln represents one or any combination of Y, La, Gd and Sc; A represents one or any combination of Li, Na, K, Rb and Cs; 0≤x≤0.5 , 0≤y≤1, 0.0001≤m≤0.01; 0≤n≤0.01. M and Ln are luminescent characteristic regulators, A is a charge compensator, and the general expression of the phosphor is: SrLu ₂ O ₄ :Ce ³⁺ .

A method for preparing a blue light-emitting phosphor suitable for excitation by near-ultraviolet light, comprising the following steps:

1) Weigh each metal element compound in the general formula according to the stoichiometric ratio, fully grind and mix;

The metal element compound is a metal element oxide or a metal element salt compound;

2) Put the mixture obtained in step 1) into high-purity corundum or other types of crucibles, and sinter for 4-8 hours at a temperature of 1500-1650 ° C under the reducing atmosphere of CO or H ₂ and N ₂ mixed gas That is to obtain a sintered body; the preferred sintering time is 1550-1600° C., and the time is 4 hours.

3) Grinding the sintered body obtained in step 2), washing, filtering, and drying to obtain a blue light-emitting phosphor suitable for excitation by near-ultraviolet light.

An application of a blue light-emitting phosphor suitable for excitation by near-ultraviolet light, the blue light-emitting phosphor is used as a light conversion material for a near-ultraviolet LED, and is applied to a blue light-emitting device or device, or the blue light-emitting phosphor is It is mixed with other color luminescent phosphors and applied to white light emitting devices or devices. The other color luminescent phosphors can be green and red phosphors suitable for excitation by near-ultraviolet light.

Example 1: Preparation of Sr _1-x M _x Lu _2-y Ln _y O ₄ :Ce ³⁺ _m ,A _n , where x=0; y=0; m=0.002; n=0; the expression is: SrLu ₂ O ₄ :Ce ³⁺ _0.002 . Weigh SrCO ₃ , Lu ₂ O ₃ and CeO ₂ according to the stoichiometric ratio, grind and mix the weighed raw materials thoroughly, put them into a high-purity corundum crucible, and under the conditions of 1600°C, H ₂ and N ₂ reducing atmosphere, After 4 hours of sintering, after cooling and discharging, a little grinding, washing, filtering and drying are performed to obtain the blue luminescent phosphor sample. Its XRD diffraction pattern is shown in Figure 1. Compared with the standard card data, it can be seen that the sample has a pure phase SrLu ₂ O ₄ structure. Its emission spectrum and excitation spectrum are shown in Figures 2 and 3. The effective excitation range of the excitation spectrum covers 380-450nm, and the excitation peak position is located near 403nm; the emission spectrum covers 417-600nm, and the emission peak position is located near 458nm. Figure 4 is the variable temperature spectrum of the sample. At 150°C, its luminous intensity is still 86% of that at 25°C, indicating that it has excellent thermal stability and has application performance. Figure 5 shows the spectrum of the white light LED obtained by combining the sample with a 405nm ultraviolet chip and combining yellow and red phosphors. White light with high color rendering index at different color temperatures can be obtained through different proportions of the components.

Example 2 to Example 122: The preparation steps are the same as in Example 1. The chemical formula, synthesis temperature, calcination time and luminous color are listed in the attached table 1. Example 2 is carried out under CO reducing atmosphere conditions. Example 2 The raw materials used in 2 to embodiment 122 are oxides or salt compounds of various metal elements.

The chemical formula, synthesis temperature, calcination time and luminous color of Example 1-122 in Attached Table 1

It can be seen from the above examples that the preparation method of the fluorescent material of the present invention is simple, pollution-free, low in cost and stable in chemical properties. The material will become a very practical blue light-emitting material suitable for excitation by near-ultraviolet light.

The method for packaging a blue light-emitting device using the blue light-emitting phosphor powder provided by the present invention and a near-ultraviolet LED tube core is as follows:

1) Bond the near-ultraviolet LED chip to the LED bracket, and connect the positive and negative poles of the LED chip to the positive and negative poles of the bracket through metal wires or conductive glue;

2) Mix the blue light-emitting phosphor powder provided by the present invention with epoxy resin or silica gel and other packaging materials, stir evenly, and let stand for 0.5h to remove air bubbles to form powder glue;

3) Coating the powder glue in step 2) in the LED bracket, covering the LED chips and metal wires;

4) Put the LED bracket in step 3) into an oven, and cure at 120-150° C. for 2-4 hours to obtain a blue light emitting device.

The method for packaging a white light-emitting device by using the blue light-emitting phosphor powder provided by the present invention and the near-ultraviolet LED tube core is as follows:

1) Bond the near-ultraviolet LED chip to the LED bracket, and connect the positive and negative poles of the LED chip to the positive and negative poles of the bracket through metal wires or conductive glue;

2) Mix the blue light-emitting phosphor powder provided by the present invention with green light and red light phosphor powders suitable for excitation by near-ultraviolet light in a certain proportion;

3) Mix the blue-green-red fluorescent mixed powder uniformly mixed in step 2) with epoxy resin or silica gel and other packaging materials, stir evenly, let stand for 0.5h to remove air bubbles, and form powder glue;

4) Coating the powder glue of step 3) in the LED bracket, covering the LED chips and metal wires;

5) Put the LED bracket in step 4) into an oven, and cure at 120-150° C. for 2-4 hours to obtain a white light emitting device.

Apparently, the above-mentioned embodiments are only examples for clear description, rather than limiting the implementation. For those of ordinary skill in the art, other changes or changes in different forms can be made on the basis of the above description. It is not necessary and impossible to exhaustively list all the implementation manners here. And the obvious changes or changes derived therefrom are still within the scope of protection of the present invention.

Claims (8)

1. a kind of blue luminescent phosphor suitable near ultraviolet excitation, it is characterised in that its formula is：Sr_1-xM_xLu_{2- y}Ln_yO₄:Ce³⁺ _m,A_n, wherein M represents one kind or any combination in Mg, Ca and Ba；Ln represents one kind in Y, La, Gd and Sc Or any combination；A represents one kind or any combination in Li, Na, K, Rb and Cs；0≤x≤0.5,0≤y≤1,0.0001≤m ≤0.01；0≤n≤0.01.

2. it is suitable to the blue luminescent phosphor of near ultraviolet excitation according to claim 1, it is characterised in that its expression formula For：SrLu₂O₄:Ce³⁺ _0.002。

3. a kind of preparation method of the blue luminescent phosphor suitable near ultraviolet excitation described in claim 1 or 2, its feature It is, comprises the following steps：

1) each metallic element compound in formula is stoichiometrically weighed, abundant finely ground mixing；

The metallic element compound is metal oxides or metallic element salt compounds；

2) by the mixture that step 1) obtains at 1500-1650 DEG C of temperature, under reducing atmosphere, sintering 4-8 hours obtain Sintered body；

3) after the sintered body grinding obtained step 2), scrubbed, filtering, drying are suitable to the blueness hair of near ultraviolet excitation Emitting phosphor.

4. preparation method according to claim 3, it is characterised in that in step 2)：The reducing atmosphere is with CO or H₂ And N₂Gaseous mixture is as reducing atmosphere.

5. preparation method according to claim 3, it is characterised in that in step 2)：The temperature of the sintering is 1550- 1600 DEG C, the time is 4 hours.

6. a kind of application of the blue luminescent phosphor suitable near ultraviolet excitation described in claim 1 or 2, its feature exist In light-converting material of the blue luminescent phosphor as black light LED, applied to blue light emitting device or device.

7. a kind of application of the blue luminescent phosphor suitable near ultraviolet excitation described in claim 1 or 2, its feature exist In the blue luminescent phosphor mixes with other colour light emitting fluorescent material, applied to white light emitting device or device.

8. the application of the blue luminescent phosphor according to claim 7 suitable near ultraviolet excitation, it is characterised in that institute It is the green glow and red light fluorescent powder for being adapted near ultraviolet excitation to state other colour light emitting fluorescent material.