Tungstate Fluorescent Powder Synthesis

White LED is a new 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. Its application value and prospects are very promising. It has attracted the attention of many governments, scientific and technological circles and industrial circles, formulated development plans and injected heavy funds into development.

Rare earth fluorescent powder used in white LED must satisfy two conditions: first, the excitation spectrum of fluorescent powder should match the emission spectrum of the selected light emitting diode to ensure higher light conversion efficiency; second, the emission spectrum of fluorescent powder can emit white light under the excitation of ultraviolet light, or blue light. The light emitted is combined with the blue light emitted by the light emitting diode to form a white light.

The steps of synthesizing white LED with tungstate fluorescent powder include:

1.The raw material is weighed according to the molar ratio of each element in the chemical formula Ba4RIII2-2xEu2x ZrWO₁₂. The raw material is a compound containing Ba₂⁺, RIII, Eu₃⁺, Zr₄⁺, W₆⁺ of barium ion. The raw material is ground and mixed evenly to obtain the mixture.

2.The mixture is pre-sintered in air with sintering temperature ranging from 300 to 1000 ℃ and time ranging from 1 to 10 hours.

3.After natural cooling, grind and mix evenly, and burn in air atmosphere. The temperature of Scorch is 1000-1500 ℃, and the time is 1-10 hours.

4.Repeat steps (3) 1-2 times to obtain tungstate fluorescent powder.

The tungstate fluorescent powder initiated by Eu₃⁺ has a emission peak of about 583 nm. It has a strong excitation efficiency in the near-ultraviolet region of 395 nm, which is just the radiation wavelength of near-ultraviolet LED wafer. Therefore, it is a good red fluorescent powder for white LED, which can meet the needs of white LED for red fluorescence. It has economic and social benefits to improve the luminous efficiency and color rendering index of white LED products.

• < Prev
• Next >