CN107033903B - Rare earth ion and transition metal ion doped single-host phosphate white phosphor and preparation method thereof - Google Patents

Abstract

The invention discloses a single-host phosphate white fluorescent powder doped with rare earth ions and transition metal ions, the general chemical formula of which is: Ca _{8.78-x-y Sr x} Bay Eu _0.06 Mn _0.16 Ce(PO ₄ ) ₇ , where 0≤x≤1.0, 0≤y≤1.0, and x and y are not 0 at the same time. The preparation method includes: a) weighing oxides, carbonates or phosphates containing Ca, Sr, Ba, Eu, Mn, Ce, P elements according to the molar ratio of each element in the general chemical formula of the phosphor, mixing, Stirring and grinding to obtain a mixture; b) placing the mixture in a reducing atmosphere, heating and calcining to obtain a sintered body; c) cooling the sintered body to room temperature and fully grinding to obtain it. The white fluorescent powder prepared by the invention has a wide excitation wavelength range, high luminous intensity, can be effectively excited by a specific ultraviolet wavelength, emits bright white light, has good thermal stability, and adopts a high-temperature solid-phase method, which has a simple preparation process and is easy to operate and control. , high safety, short preparation time, high production efficiency, suitable for industrialized large-scale production and application.

Description

White fluorescence of a single-host phosphate doped with rare earth ions and transition metal ions Powder and preparation method thereof

technical field

The invention relates to a luminescent material and a preparation method, in particular to a single-host phosphate white phosphor doped with rare earth ions and transition metal ions and a preparation method thereof.

Background technique

White LED (Light Emitting Diode, light-emitting diode) is considered to be the fourth generation of solid-state lighting sources to replace traditional incandescent lamps, fluorescent lamps and high-intensity gas discharge lamps. LED devices have the advantages of energy saving, high efficiency, environmental protection, small size, long service life, high reliability, and intelligent control, and are widely used in various lighting and display fields.

At present, there are four main ways for LEDs to achieve white light emission: (1) LED chips that emit red, green and blue light respectively are combined together, so that red, green and blue lights are superimposed together to form white light; (2) Near Ultraviolet or violet LED chips excite three phosphors that emit red light, green light, and blue light respectively, and red, green, and blue light are mixed into white light; (3) The blue LED chip excites yellow phosphors, and blue light and yellow light are mixed into white light; (4) The ultraviolet LED chip excites the white light emitting single matrix phosphor. The first implementation method requires different driving voltages for red, green, and blue LEDs, the circuit is complex, the cost is high, and the scope of use is narrow. In the second solution, due to the absorption effect of the blue phosphor on the red light emitted by the red phosphor, the white light formed produces a color shift phenomenon during actual use. At present, the most widely used technical solution is the third one. The blue LED used is gallium nitride diode. The yellow phosphor with more mature technology is YAG:Ce ³⁺ , which can be effectively excited by the blue LED chip of 440-480nm. It is mixed with blue light to form white light, which has the advantages of high luminous brightness, high electro-optical conversion efficiency, and strong thermal stability, but there are also some obvious shortcomings, such as the lack of red components in the spectrum, resulting in higher color temperature, cooler luminous color, and color rendering. Poor, and the particle size of the phosphor powder synthesized by the reaction is not easy to control. The fourth solution has attracted more and more attention in recent years. Single-matrix three-primary phosphors have many advantages, such as effectively avoiding self-absorption, high color rendering index, and adjustable color and color temperature. Therefore, the continuous development of more types of single-matrix trichromatic phosphors is a topic actively explored by R&D personnel in the industry.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a single-host phosphate white fluorescent powder doped with rare earth ions and transition metal ions and a preparation method thereof, so as to provide more choices for the white fluorescent powder in the market.

The object of the present invention is achieved through the following technical solutions: a single-host phosphate white phosphor doped with rare earth ions and transition metal ions, is characterized in that, its general chemical formula is:

Ca _{8.78-xy Sr x} Bay Eu _0.06 Mn _0.16 Ce(PO ₄ ) ₇ , where 0≤x≤1.0, 0≤y≤1.0, and x and y are not 0 at the same time.

Preferably, when x=0.2 and y=0.2 in the general chemical formula, the prepared phosphor has the best thermal stability.

The invention also discloses a preparation method of a single-host phosphate white fluorescent powder doped with rare earth ions and transition metal ions, comprising the following steps:

(a) According to the general chemical formula of the phosphor, Ca _{8.78-xy Sr x} Bay Eu _0.06 Mn _0.16 Ce(PO ₄ ) ₇ , the molar ratio of each element in the phosphor powder was weighed to contain Ca, Sr, Ba, Eu, Mn, Ce, P Oxides, carbonates or phosphates of elements, mixed, stirred and ground to obtain a mixture, in the general chemical formula 0<x≤1.0, 0<y≤1.0, and x and y are not 0 at the same time;

(b) placing the mixture in a reducing atmosphere, heating to 1150-1250° C. and calcining for 7-8 hours to obtain a sintered body;

(c) The obtained sintered body is cooled to room temperature and then fully ground to obtain a phosphate white phosphor doped with rare earth ions and transition metal ions.

The grinding time of step (a) is 20-30min.

The chemical formula of the phosphor described in step (a) is Ca _8.38 Sr _0.2 Ba _0.2 Eu _0.06 Mn _0.16 Ce(PO ₄ ) ₇ , and the phosphor has the best thermal stability.

The heating rate in step (b) is 2-5°C/min.

The reducing atmosphere in step (b) refers to a reducing atmosphere formed by embedding large particle size carbon powder or a mixed gas of H ₂ and N ₂ .

In step (b), the temperature is raised to 1150-1250°C for 8h calcination, preferably 1200°C for 8h.

In the prior art, most phosphors with single-host doping elements cannot simultaneously generate luminescent centers that emit red light, green light and blue light, so that the acquired white light has insufficient spectral content and poor display performance, limiting the application of such white phosphors. The phosphor provided by the present invention forms a luminescent center by doping a specific proportion of rare earth ions Eu ²⁺ and transition metal ions Mn ²⁺ into a single matrix as an activator and a sensitizer, which is derived from the matrix-sensitized luminescence mechanism, and successfully The above technical obstacles are overcome, and by doping Sr and Ba and a specific Sr/Ba doping ratio, a bright and thermally stable single phosphate-based white phosphor is obtained. The phosphor powder prepared by the invention has strong broadband absorption at 280-350nm, and the emission wavelength range is 360-750nm. Within this wavelength range, full-spectrum emission can be realized, which meets the excitation requirements of near-ultraviolet LED chips. In addition, the white fluorescent powder prepared by the invention has a wide excitation wavelength range and high luminous intensity, can be effectively excited by a specific ultraviolet wavelength, and emits bright white light. In the present invention, by doping Sr and Ba and a specific doping ratio of Sr/Ba, the luminous intensity of the phosphor under high temperature conditions is significantly improved. The high-temperature solid-phase method adopted by the white phosphor provided by the invention has the advantages of simple preparation process, easy operation and control, high safety, short preparation time and high production efficiency, and is suitable for industrialized large-scale production and application.

Description of drawings

FIG. 1 is a comparison diagram of the XRD patterns of the phosphors prepared in Example 1 and Example 6 and the standard pattern.

FIG. 2 is the excitation and emission spectra of the phosphor prepared in Example 3. FIG.

3 is the color coordinates of the phosphors prepared in Examples 1, 5, 6, 10 and 12 of the present invention.

FIG. 4 is the temperature-variable spectrum of the phosphors prepared in Examples 1, 6, 12 and Comparative Example 1 of the present invention.

Detailed ways

The following examples are used to further illustrate the present invention in detail, but do not limit the present invention in any form.

Example 1

(1) Weigh each raw material by the following weights: 1.139 g of CaCO ₃ , 0.039 g of SrCO ₃ , 0.014 g of Eu ₂ O ₃ , 0.024 g of MnCO ₃ , 1.068 g of NH ₄ H ₂ PO ₄ , 0.228 g of CeO ₂ , mix uniformly, stir, and grind for 20min to obtain a mixture;

(2) The ground mixture powder is placed in a small crucible, and calcined in a reducing atmosphere of H ₂ and N ₂ (the volume ratio of H ₂ and N ₂ is 9:1) at a heating rate of 2°C/min The temperature was raised to 1200°C, sintered at this temperature for 8 hours, and cooled to room temperature naturally to obtain a sintered body;

(3) The obtained sintered body is cooled to room temperature and then fully ground to obtain a single-host phosphate white phosphor Ca _8.58 Sr _0.2 Eu _0.06 Mn _0.16 Ce(PO ₄ ) ₇ doped with rare earth ions and transition metal ions.

Example 2-5

The preparation method of embodiment 2-5 is the same as that of embodiment 1, only the proportion of raw materials is different, and its proportion and the prepared phosphor chemical formula are as follows:

project prepared phosphor CaCO₃/g SrCO₃/g Eu₂O₃/g MnCO₃/g NH₄H₂PO₄/g CeO₂/g Example 2 Ca_8.38Sr_0.4Eu_0.06Mn_0.16Ce(PO₄)<sub >7</sub> 1.112 0.078 0.014 0.024 1.068 0.228 Example 3 Ca_8.18Sr_0.6Eu_0.06Mn_0.16Ce(PO₄)<sub >7</sub> 1.086 0.117 0.014 0.024 1.068 0.228 Example 4 Ca_7.98Sr_0.8Eu_0.06Mn_0.16Ce(PO₄)<sub >7</sub> 1.059 0.157 0.014 0.024 1.068 0.228 Example 5 Ca_7.78Sr_1.0Eu_0.06Mn_0.16Ce(PO₄)<sub >7</sub> 1.033 0.196 0.014 0.024 1.068 0.228

Example 6

(1) Weigh each raw material by the following weights: 1.139 g of CaCO ₃ , 0.052 g of BaCO ₃ , 0.014 g of Eu ₂ O ₃ , 0.024 g of MnCO ₃ , 1.068 g of NH ₄ H ₂ PO ₄ , 0.228 g of CeO _2. Mix evenly, stir, and grind for 20 minutes to obtain a mixture;

(2) The ground mixture powder is placed in a small crucible, and calcined in a reducing atmosphere of H ₂ and N ₂ (the volume ratio of H ₂ and N ₂ is 9:1) at a heating rate of 2°C/min The temperature was raised to 1200°C, sintered at this temperature for 8 hours, and cooled to room temperature naturally to obtain a sintered body;

(3) The obtained sintered body is cooled to room temperature and then fully ground to obtain a single-host phosphate white phosphor Ca _8.58 Ba _0.2 Eu _0.06 Mn _0.16 Ce(PO ₄ ) ₇ doped with rare earth ions and transition metal ions.

Examples 7-10

The preparation method of embodiment 7-10 is the same as that of embodiment 6, only the proportion of raw materials is different, and its proportion and the prepared phosphor chemical formula are as follows:

project Prepared Phosphate Phosphors CaCO₃/g BaCO₃/g Eu₂O₃/g MnCO₃/g NH₄H₂PO₄/g CeO₂/g Example 7 Ca_8.38Ba_0.4Eu_0.06Mn_0.16Ce(PO₄)<sub >7</sub> 1.112 0.105 0.014 0.024 1.068 0.228 Example 8 Ca_8.18Ba_0.6Eu_0.06Mn_0.16Ce(PO₄)<sub >7</sub> 1.086 0.157 0.014 0.024 1.068 0.228 Example 9 Ca_7.98Ba_0.8Eu_0.06Mn_0.16Ce(PO₄)<sub >7</sub> 1.059 0.209 0.014 0.024 1.068 0.228 Example 10 Ca_7.78Ba_1.0Eu_0.06Mn_0.16Ce(PO₄)<sub >7</sub> 1.033 0.262 0.014 0.024 1.068 0.228

Example 11

(1) Weigh each raw material by the following weights: 1.123 g of CaCO ₃ , 0.039 g of SrCO ₃ , 0.026 g of BaCO ₃ , 0.014 g of Eu ₂ O ₃ , 0.024 g of MnCO ₃ , 1.065 g of NH ₄ H ₂ PO ₄ , 0.228 g of CeO ₂ , mix uniformly, stir, and grind for 20 min to obtain a mixture;

(2) The ground mixture powder is placed in a small crucible, and calcined in a reducing atmosphere of H ₂ and N ₂ (the volume ratio of H ₂ and N ₂ is 9:1) at a heating rate of 2°C/min The temperature was raised to 1200°C, sintered at this temperature for 8 hours, and cooled to room temperature naturally to obtain a sintered body;

(3) The obtained sintered body is cooled to room temperature and then fully ground to obtain a single-host phosphate white phosphor Ca _8.48 Sr _0.2 Ba _0.1 Eu _0.06 Mn _0.16 Ce(PO ₄ ) ₇ doped with rare earth ions and transition metal ions.

Examples 12-14

The preparation method of embodiment 12-14 is the same as that of embodiment 11, only the raw material ratio is different, and its ratio and the prepared phosphor chemical formula are as follows:

project Prepared Phosphate Phosphors CaCO₃/g SrCO₃/g BaCO₃/g Eu₂O₃/g MnCO₃/g NH₄H₂PO₄/g CeO₂/g Example 12 Ca_8.38Sr_0.2Ba_0.2Eu_0.06Mn_0.16Ce(PO<sub >4</sub>)₇ 1.110 0.039 0.052 0.014 0.024 1.065 0.228 Example 13 Ca_8.28Sr_0.4Ba_0.1Eu_0.06Mn_0.16Ce(PO<sub >4</sub>)₇ 1.097 0.078 0.026 0.014 0.024 1.065 0.228 Example 14 Ca_8.18Sr_0.4Ba_0.2Eu_0.06Mn_0.16Ce(PO<sub >4</sub>)₇ 1.083 0.078 0.052 0.014 0.024 1.065 0.228

Comparative Example 1

(1) Weigh each raw material by the following weights: 1.165g CaCO ₃ , 0.014g Eu ₂ O ₃ , 0.024g MnCO ₃ , 1.068g NH ₄ H ₂ PO ₄ , 0.228g CeO ₂ , mix well, Stir and grind for 20min to obtain a mixture;

(2) The ground mixture powder is placed in a small crucible, and calcined in a reducing atmosphere of H ₂ and N ₂ (the volume ratio of H ₂ and N ₂ is 9:1) at a heating rate of 2°C/min The temperature was raised to 1200°C, sintered at this temperature for 8 hours, and cooled to room temperature naturally to obtain a sintered body;

(3) The obtained sintered body is cooled to room temperature and then fully ground to obtain a single-host phosphate white phosphor Ca _8.78 Eu _0.06 Mn _0.16 Ce(PO ₄ ) ₇ doped with rare earth ions and transition metal ions.

Example 15 The optical and other properties of the phosphors prepared in Examples and Comparative Examples were examined.

experimental method:

Ca _8.58 Sr _0.2 Eu _0.06 Mn _0.16 Ce(PO ₄ ) ₇ and Ca _8.58 Ba _0.2 Eu _0.06 Mn _0.16 Ce(PO ₄ ) ₇ prepared in Examples 1 and 6 were detected, and the X-ray diffraction patterns of the phosphors were obtained as shown in Figure 1 shown.

Detect the Ca _8.18 Sr _0.6 Eu _0.06 Mn _0.16 Ce(PO ₄ ) ₇ prepared in Example 3, and obtain its excitation and emission spectra, as shown in Figure 2, the excitation wavelength in the figure is λ _ex =320nm, and the emission band is from 360nm to 750nm, The composite white light emission was obtained, and the white light emitting phosphor excited by the near-ultraviolet LED was successfully prepared.

The phosphors Ca _8.58 Sr _0.2 Eu _0.06 Mn _0.16 Ce(PO ₄ ) ₇ , Ca _7.78 Sr _1.0 Eu _0.06 Mn _0.16 Ce ( PO ₄ ) ₇ , Ca _8.58 Ba _0.2 Eu _0.06 Mn _0.16 Ce(PO ₄ ) ₇ , Ca _7.78 Ba _1.0 Eu _0.06 Mn _0.16 Ce(PO ₄ ) ₇ and Ca _8.38 Sr _0.2 Ba _0.2 Eu _0.06 Mn _0.16 Ce(PO ₄ ) The color coordinates of ₇ are shown in Fig. 3; it shows that the synthesized phosphor achieves adjustable color and controllable color temperature on the basis of white light emission.

The Ca _8.58 Sr _0.2 Eu _0.06 Mn _0.16 Ce(PO ₄ ) ₇ , Ca 8.58 Ba 0.2 Eu 0.06 Mn 0.16 Ce(PO 4 ) 7 , Ca _8.58 Ba _0.2 Eu _0.06 Mn _0.16 Ce(PO ₄ ) ₇ , Ca _8.38 Sr _0.2 Ba _0.2 Eu _0.06 Mn _0.16 Ce(PO ₄ ) ₇ , Ca _8.78 Eu _0.06 Mn _0.16 Ce(PO ₄ ) ₇ temperature-variable spectrum, after doping Sr or Ba alone, the luminescence temperature stability of the material is improved. When doping Sr and Ba at the same time, the luminescence temperature stability of the material is further improved, as shown in (a), (b), (c), and (d) in Figure 4.

The preparation methods described in the specification of the present invention can all prepare the phosphors to be protected by the present invention, and the phosphors prepared under the disclosed process parameters have basically similar experimental effects to some phosphors tested in Example 15.

Claims (5)

1. A single-host phosphate white phosphor doped with rare earth ions and transition metal ions is characterized in that, its general chemical formula is: Ca _{8.78-xy Sr x} Bay Eu _0.06 Mn _0.16 Ce(PO ₄ ) ₇ , where x=0.2, y=0.2. 2. A method for preparing a single-host phosphate white phosphor doped with rare earth ions and transition metal ions, comprising the following steps: (a) According to the general chemical formula of the phosphor, Ca _{8.78-xy Sr x} Bay The molar ratio of each element in Eu _0.06 Mn _0.16 Ce(PO ₄ ) ₇ Weigh oxides, carbonates or phosphates containing Ca, Sr, Ba, Eu, Mn, Ce, P elements, mix, stir, grind, A mixture is obtained, where x=0.2, y=0.2 in the general chemical formula; (b) the mixture is placed in a reducing atmosphere, heated to 1150-1250° C. and calcined for 7-8 hours to obtain a sintered body; (c) the The obtained sintered body is cooled to room temperature and then fully ground to obtain a single-matrix phosphate white phosphor doped with rare earth ions and transition metal ions. 3 . The method for preparing a single-host phosphate white phosphor doped with rare earth ions and transition metal ions according to claim 2 , wherein the grinding time in step (a) is 20-30 min. 4 . 4 . The method for preparing a single-host phosphate white phosphor doped with rare earth ions and transition metal ions according to claim 2 , wherein the heating rate in step (b) is 2-5° C./min. 5 . 5 . The method for preparing a single-host phosphate white phosphor doped with rare earth ions and transition metal ions according to claim 2 , wherein the reducing atmosphere in step (b) refers to embedding large particle size carbon powder. 6 . Or a reducing atmosphere formed by a mixed gas of H ₂ and N ₂ .

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