[High-tech LED News] It is reported that the Institute of Materials Technology and Engineering of the Chinese Academy of Sciences cooperated with the Thousand People of Zhejiang Province to successfully produce high-quality nitride phosphors under low temperature and normal pressure by microwave method.
The basic heating principle is to use the coupling of the raw material molecules and the electromagnetic field to convert the microwave energy into heat energy to heat the object. Therefore, the conventional air pressure synthesis method can achieve uniform zero-gradient heating in a large area of ​​the material, and the heating rate is fast and the sintering time is short. It is advantageous to obtain a powder having a uniform particle size distribution. For example, a high-quality white LED with Ca-α-SiAlON:Eu2+ phosphor was successfully synthesized at a pressure of 1550 ° C. The synthesis temperature was reduced by 150 ° C compared with the conventional air pressure method (1700 °, 0.5 MPa nitrogen protection). Moreover, compared with the luminescent properties of the powder synthesized by the pneumatic method under the same temperature conditions, the luminescence intensity, quantum efficiency and thermal stability are significantly improved. The external quantum efficiency of the unoptimized phosphor tested at 450 nm excitation is up to 48%, which is expected to reach or exceed the luminous efficiency of commercial powders after sieving and purification.
The successful development of the low-cost technology of nitride phosphor powder will greatly reduce the cost reduction of high-power LED lighting devices and backlight display, and will accelerate the process of promoting semiconductor lighting technology in China on a large scale. At present, the technology has applied for Chinese invention patent (201110152682.4) and PCT patent protection, and is promoting pilot production.
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