What is the Nitride system?
The red phosphors of nitride system have good thermal stability and chemical stability, which are the activator ions used in nitride system. The electronegativity of the compounds containing silicon is very small.
The covalent property of the phosphor has become stronger, which leads to the shift of the center of gravity and the expansion of the electron cloud, which makes the spectrum of the phosphor easy to be broadened, and the position of the spectrum peak can be redshift. Based on the above characteristics, the study of red phosphors in nitride system has received great attention in recent years. It has been developed as a new type of red luminescent LED phosphors, which can effectively absorb light from near ultraviolet to blue-green wavelength and efficiently emit yellow, orange and red light from 550 nm to 750nm, and increase the concentration of doped EU. The emission wavelength gradually redshifts towards the long wave direction.
From the point of view of EU luminescence performance, it can improve the luminescent quality of white LED. It is a kind of red phosphor used in LED with wide application prospect. The excitation spectra of the phosphors were not changed by replacing Sr with Ca, but the emission spectra of the phosphors were similar to those of the red phosphors, due to the red shift of EU to 4f at 620-643 nm. Conclusion in the process of making white LED with fluorescence conversion type,the white light can be changed by adjusting the excitation and emission peak position of phosphor output quality has a certain help.
The EU phosphor synthesized by indexing A1 element into the substrate is a new type of nitride red phosphor. It has excellent luminescence property and can bring some hope for the application of white LED. The excitation spectra of this kind of phosphors have a strong absorption peak in the blue region of 450nmn. The emission peak is located in the broadband region, and the peak position gradually shifts to the long wave direction with the increase of EU content, and the band range is generally 640,690mm.
Under the excitation of 375 ~ 450 nm, the powder emits a higher intensity of red light at 630 wavelength.
The quantum efficiency decreases with the increase of EU concentration.
Generally, silicon containing nitride phosphors have rigid covalent bonds, so only small shifts of EU ions occur in the red phosphors. Therefore, nitride phosphors can efficiently absorb the blue LED chip light and emit high intensity red light, which will be an ideal substrate material for the manufacture of white LED.
This article is from Allicdata Electronics Limited.