CN103254898A - Thulium and dysprosium co-doped sodium yttrium tungstate white luminescent material and its use - Google Patents

Abstract

The invention discloses a white light luminescent material Tm ³⁺ :Dy ³⁺ :NaY(WO ₄ ) ₂ , and relates to the field of luminescent materials. The chemical formula of the white light-emitting material is Tm ³⁺ :Dy ³⁺ :NaY(WO ₄ ) ₂ , which belongs to the tetragonal phase, and the space group is

, the unit cell parameters are a = b = 5.205 Å, c = 11.251 Å , α = β = γ = 90°, V = 304.81 Å ³ , Z= 2. This material is used to produce white fluorescence.

Description

Thulium-dysprosium co-doped yttrium sodium tungstate white light luminescent material and application thereof

technical field

The invention relates to the field of luminescent materials.

Background technique

White LEDs have many advantages that other traditional lighting sources cannot match, such as high luminous efficiency, low power consumption, long life, and environmental protection. Therefore, it is considered to be the most potential lighting source to replace incandescent lamps and fluorescent lamps. Its application prospects are extremely promising, and it can be used in large quantities for conventional lighting. It is only a matter of time before it replaces conventional light sources.

At present, the white light LED is mainly implemented by using ultraviolet chips and three primary color phosphors, which have the advantages of low cost, high color rendering, stable color, adjustable light color and color temperature, but there are also serious shortcomings, that is, it is not easy to find three primary color phosphors. A high-efficiency phosphor, there are color reabsorption and ratio control problems between phosphors, which seriously affects the luminous efficacy of white LEDs. In order to overcome this problem, a single host phosphor doped with a single active ion (eg Dy ³⁺ , Pr ³⁺ ) or a variety of rare earth ions can be used.

Contents of the invention

The purpose of the present invention is to disclose a white light emitting material Tm ³⁺ :Dy ³⁺ :NaY(WO ₄ ) ₂ .

，晶胞参数是 ,α = β = γ = 90°,

, Z= 2。 The invention provides a white light emitting material with the chemical formula Tm ³⁺ :Dy ³⁺ :NaY(WO ₄ ) ₂ , which belongs to the tetragonal phase and the space group is

, the cell parameters are ,α = β = γ = 90°,

, Z=2.

The Tm ³⁺ and Dy ³⁺ are used as activated luminescent ions, and the doping concentrations of Tm ³⁺ and Dy ³⁺ are both 1at%-20at%.

The Tm ³⁺ :Dy ³⁺ :NaY(WO ₄ ) ₂ material is used to generate white fluorescence.

Regulating the doping concentration of Tm ³⁺ and Dy ³⁺ of the material controls its chromaticity coordinates, and produces the white fluorescent chromaticity coordinates in the range of (0.25-0.4, 0.2-0.35).

When white light LEDs are mainly realized by using ultraviolet chips and three primary color phosphors, it is difficult to find three high-efficiency phosphors, and there are problems of color reabsorption and ratio control between phosphors, which seriously affect the luminescence of white light LEDs. effect. To overcome these disadvantages, single-matrix LED phosphors can be used. NaY(WO ₄ ) ₂ is used as a single matrix of the phosphor, and Dy ³⁺ and Tm ³⁺ ions are used as luminescence active ions. When the Dy ³⁺ :NaY(WO ₄ ) ₂ sample _is excited by a 352nm ultraviolet light source, there are two strong emission peaks located at 474nm and 574nm, corresponding to ⁴ F ^9/2 → ⁶ H _{15/ 2} , ⁴ F _9/2 → ⁶ H _13/2 transition, a weaker red emission is located at 652nm, corresponding to ⁴ F _9/2 → ⁶ H _11/2 transition. The yellow light emission is obviously stronger than the blue light emission, and the CIE chromaticity coordinates all fall in the yellow light area. However, since the ¹ D ₂ → ³ F ₄ transition of Tm ³⁺ ions corresponds to blue light emission (~450nm), co-doping Tm ³⁺ and Dy ³⁺ ions can effectively supplement the blue light component. When excited by a 353nm ultraviolet light source, compared with the sample doped with Dy ³⁺ ions, there is obviously a strong blue emission at 450nm, corresponding to the ¹ D ₂ → ³ F ₄ transition of Tm ³⁺ ions, and the rest One is the characteristic emission peak transition of Dy ³⁺ ion. As the doping concentration of Tm ³⁺ ions increases, the luminescence of the sample moves from the yellow light to the blue light region, and the color temperature increases. The emission of several samples all falls in the white light region, and the emission spectrum diagram is shown in the attached figure, wherein the chromaticity coordinates of NaY(WO ₄ ) ₂ doped 1at%Tm ³⁺ and 2.5at%Dy ³⁺ samples are (0.336,0.337 ), which is closest to the chromaticity coordinates (0.33,0.33) of standard white light. This shows that white light-emitting NaY(WO ₄ ) ₂ doped 1at%Tm ³⁺ and 2.5at%Dy ³⁺ phosphors have application prospects in UV chip-based white LEDs.

Description of drawings

The attached figure shows the emission spectra of different Tm ³⁺ ion concentrations when the Dy ³⁺ ion concentration is fixed at 2.5%, and the excitation wavelength is 353nm.

Detailed ways:

Example 1:

Thulium-dysprosium co-doped sodium yttrium tungstate NaDy _x Tm _y Y _1-xy (WO ₄ ) ₂ samples were synthesized by traditional high-temperature solid-state method, x=1at%~20at%, y=1at%~20at%. Weigh raw materials Na ₂ CO ₃ , Y ₂ O ₃ , WO ₃ , Dy ₂ O ₃ and Tm ₂ O ₃ according to the stoichiometric ratio in the following chemical reaction formula:

Na ₂ CO ₃ + (1-xy)Y ₂ O ₃ + 4WO ₃ + xDy ₂ O ₃ + yTm ₂ O ₃ →

2Na Dy _x Tm _y Y _1-xy (WO ₄ ) ₂ + CO ₂ ↑

The raw materials were mixed and ground in an agate mortar, and the raw materials used were analytically pure Na ₂ CO ₃ , Y ₂ O ₃ , WO ₃ and Dy ₂ O ₃ and Tm ₂ O ₃ of 4N purity. Transfer the ground mixture into a platinum crucible, sinter in a muffle furnace at 900°C for 12 hours, grind the mixed sample again after cooling, test the X-ray powder diffraction XRD pattern of the sample, supplement the missing components, and then repeat the above sintering process , Until the X-ray powder diffraction XRD spectrum of the raw material obtained is unchanged, it is identified as the desired compound.

Example 2:

Thulium-dysprosium co-doped sodium yttrium tungstate NaDy _x Tm _y Y _1-xy (WO ₄ ) ₂ samples were synthesized by traditional high-temperature solid-state method, x=1at%~20at%, y=1at%~20at%. Weigh raw materials Na ₂ WO ₄ , Y ₂ O ₃ , WO ₃ , Dy ₂ O ₃ and Tm ₂ O ₃ according to the stoichiometric ratio in the following chemical reaction formula:

Na ₂ WO ₄ + (1-xy)Y ₂ O ₃ + + xDy ₂ O ₃ + yTm ₂ O ₃ + 3WO ₃ →

2Na Dy _x Tm _y Y _1-xy (WO ₄ ) ₂

The raw materials were mixed and ground in an agate mortar, and the raw materials used were analytically pure Na ₂ WO ₄ , Y ₂ O ₃ , WO ₃ and Dy ₂ O ₃ and Tm ₂ O ₃ of 4N purity. Transfer the ground mixture into a platinum crucible, sinter in a muffle furnace at 900°C for 12 hours, grind the mixed sample again after cooling, test the X-ray powder diffraction XRD pattern of the sample, supplement the missing components, and then repeat the above sintering process , Until the X-ray powder diffraction XRD spectrum of the raw material obtained is unchanged, it is identified as the desired compound.

Claims (4)

1. chemical formula is Tm ³⁺: Dy ³⁺: NaY (WO ₄) ₂Luminescent material, belong to cubic phase, spacer is

, unit cell parameters is a=b=5.205, c=11.251, and α=β=γ=90 °, V=304.81 3, Z=2.

2. material according to claim 1 is characterized in that: described Tm ³⁺And Dy ³⁺As activating light emitting ionic, doping content is 1at% ~ 20at%.

3. the described Tm of claim 1 ³⁺: Dy ³⁺: NaY (WO ₄) ₂Material is for generation of white fluorescent.

4. Tm as claimed in claim 3 ³⁺: Dy ³⁺: NaY (WO ₄) ₂The purposes of material is characterized in that: the Tm that regulates and control described material ³⁺With Dy ³⁺Doping content control its tristimulus coordinates, produce described white fluorescent tristimulus coordinates scope for (0.25-0.4,0.2-0.35).

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