Optimize Synthesis Of Nitride Based On Mathematical Principles Of Statistical, Crystal Structure Analysis, And Energy Transfer Of LED Fluorescent Materials

Solid state lighting, which is made of the third generation semiconductor material, is the fourth generation lighting device after incandescent, fluorescent, high-pressure gas discharge lamp. White light-emitting diodes with high efficiency, energy saving, and environmental protection, have partially taken the place of conventional lighting in the modern society, and will replace all in the future. There is a large relationship between WLED (White light emitting diode) lights and people’s life.Compared with yellow and green phosphors, red phosphors need more research. Nitride Sr2Si5N8:Eu2+, due to good thermal and chemical stability, broad excitation and emission spectra, become very promising red phosphor. However, strict reaction conditions and high cost limit its application in the white LED. To this end, metal oxide was used as raw materials to explore a mild synthesis method. Taguchi Orthogonal Design and High-energy ball milling were combined to implement a separate milling and co-milling of SrCO3 and Si3N4. X-ray, fluorescence spectrum, and infrared spectroscopy were used to detect product, structure and spectra, which shows that impurities were due to S-N breakage and increasing oxygen content during milling process and Sr volatiles. In this regard, measures of protecting the integrity of Si-N bond and SrCO3 separate milling process, as well as improving raw material Sr/Si ratio were adoped to explored to sueecssfully synthesize high purity Sr2Si5Ng: Eu2+phosphor.The energy transfer between Ce3+ and Eu2+ were studied. On the discovery of exsiting crystal structure can not explain the experimentally measured Li2SrSiO4:Eu2+, Ce3+ excitation and emission spectra, X-ray diffraction, OPO, high resolution transmission electron microscopy and low-temperature spectrum were used to determine the structure of Li2SrSiO4. Li2SrSiO4 belongs to monoclinic structure, with the space group of C121. This could explain the excitation and emission spectrum better.For the deep UV LED applications, this paper studied energy thansfer between luminescence centers Bi3+, Sb3+ and Eu3+ ions of YBO3 matrix. The results showed that Bi3+ able to stimulate effective transfer to Eu3+, but Sb3+ with the same ns2 electron configuration with Bi3+can’t, due to large Stokes shift between excitation and emission bands.