Study on the Synthesis and Luminescence Characteristics of Red Light-emitting Sr4Al14O25 Phosphor

• Main Authors: Jiang, Cheng-Hong, 姜丞鴻
• Other Authors: Lee, Jiann-Shing
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/11771905587758426162

碩士 === 國立屏東大學 === 應用物理系碩士班 === 104 === In response to the renewable and clear energy development, the white LED had been widely studied in the area of illumination. However, the rare earth-based white LED is expensive and thus it is difficult to become an increasingly popular lighting. One of the ways to solve the problems is the development of non-rare-earth emitting phosphors for LED. In this work, we report on a systematic study of the synthesis strontium aluminate phosphor and its red light-emitting mechanism. The strontium aluminate materials were prepared by solid-state reactions in the study. The mixture was milled in a high energy ball mill to provide particles having substantially uniformly distributed. In addition to the synthesis of pure Sr4Al14O25, samples of different Mn doping contents were also prepared in the study. However, no impurity crystalline phase was detected for the Mn4+-doped Sr4Al14O25 samples. A characteristic 652.7 nm fluorescent peak of the sample are significantly enhancing in these Mn4+-doped specimens. However, no wavelength shift of emission peaks was found for these samples. To figure out the influence of different impurity on the emission peaks, a systematic doping with different transition metals or other elements (Fe、Cr、V、Co and W) were carried out. With the hope to investigate the mechanism of red fluorescence and its enhancement effect, the band structure of strontium aluminate was proposed through the first-principles calculations. Data of temperature-dependent PL analysis on these samples can be fitted with the Varshni Equation and Fermi-Dirac distribution, and thus the relationship between temperature and luminescence properties were revealed. The experimental results shows that the non-rare-earth-doped phosphors can be developed with a great potential, owing that the inexpensive transition metals (Mn4+, Fe3+) can significantly enhance the fluorescent intensity of Sr4Al14O25.