Tungstate Red Phosphor

Tungstate red phosphor white LED is a new type of solid-state lighting electric light source (SSL). Its principle and structure are different from those of previous vacuum electric light sources such as incandescent lamp and fluorescent lamp. SSL light source has many advantages, especially high light efficiency, energy saving, long life and pollution-free. It has great application value and prospects.

The tungstate has a wide variety of tungstate structures. The existing tungstate is a study object with Eu₃⁺ doped M_x(WO₄)_y(Gd₂(WO₄)₃), M_x(WO₄)₃), M_x(WO₆)_y (for example, for example), but the amount of tungsten elements is larger when the above materials are prepared. Because tungsten is a valuable material, the high temperature solid state method of high temperature energy consumption and sol-gel and water heat used in the preparation of tungstate phosphor materials are prepared. The cost of tungstate is high due to the time-consuming synthesis methods, which is unfavorable for reducing the cost of phosphors. Therefore, finding a more economical and convenient synthesis method of tungstate materials is one of the focuses of current research.

Some scholars used the following steps to prepare tungstate red phosphors excited by near ultraviolet or blue light:

Some scholars used the following steps to prepare tungstate red phosphors excited by near ultraviolet or blue light:

1. 0.336g analytical pure LaCl₃·6H₂O and 0.018g analytical pure EuCl_3·6H₂O were weighed and dissolved in 20 mL deionized water to obtain rare earth solution.

2. 0.165g analytical pure Na₂WO_4·2H₂O was dissolved in 50 mL deionized water, and then the pH value of the solution was adjusted by ammonia water to get Na₂WO₄ solution.

3.Under stirring conditions, the rare earth solution prepared in step 1 is dripped into the Na₂WO₄ solution prepared in step 2. After all the rare earth solution is dripped into the solution, the white suspension is stirred for 30 minutes to complete the reaction, filter and obtain the precipitate.

4.Wash the sediment obtained by step 3 with deionized water, then centrifuge the sediment out of the water and dry it in a drying box at 200 ℃ for 1 hour.

5.The precipitate treated by step 4 is put into muffle furnace, sintered at 800 ℃ for 2 hours, then cooled and ground to obtain tungstate red phosphors excited by near ultraviolet or blue light.

The luminescence intensity of the prepared tungstate red phosphor under near-ultraviolet and blue light excitation can reach 3-12 times that of Y₂O₂S:Eu commercial phosphor, and it has the same luminescent properties as other tungstate phosphor materials. With the same luminescent center (Eu) capacity, the amount of W is the lowest, the synthesis cycle is only 2-7 hours, and the cost is the lowest. It can be used to complement the red light component of GaN-based blue light emitting diode with YAG: Ce phosphor white LED system, and also can be used as red phosphor of tri-basic white LED of near-ultraviolet chip.

• < Prev
• Next >