Synthesis, Luminescence Characterization and Potential Applications of Rare Earth Fluorosulfide and Fluorooxysulfide Phosphors

• Main Authors: Huang, Yun-Chi, 黃云琪
• Other Authors: Chen, Teng-Ming
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/77206348880428747842

碩士 === 國立交通大學 === 應用化學系碩博士班 === 101 === White LEDs fabricated with blue or near-UV LED chips and compatible R/G/B phosphors is the main stream of current solid-state lighting device. This research is attempted to develop new fluorosulfide and oxyfluorosulfide phosphors undisclosed in the literature or patent application. We have prepared four series phosphors with compositions of CeSF:Lnn+ (Lnn+ = Gd3+, Y3+, Tb3+, Mn2+), La3OF3S2:Ce3+, Ce2CaF4S2:Tb3+ and (Ce1-xYx)2SrF4S2 by solid-state reactions in evacuated sealed quartz glass tubes at 900-1000℃, which were further characterized by powder X-ray diffraction, fluorescence spectroscopy, and electron microscopy to investigate their phase identity, luminescence, microstructures, chromaticity, quantum efficiency and thermal luminescence quenching behaviors. Based on the characterization results, we then evaluated their potential applications in fabrication of white light LEDs. This thesis first investigates the optimization of synthesis conditions and performs X-Ray diffraction characterization and phase identifications. The second part deals with the luminescence of La3OF3S2:Ce3+ and the third part investigates the luminescence of Mn2+-doped fluorosulfide and oxyfluorosulfide phosphors. Fourthly, this research investigates the luminescence of Ce3+/Tb3+-codoped fluorosulfides and studies the possibility of Ce3+ → Tb3+ energy transfer. Finally, we investigated the thermal luminescence quenching property of all synthesized phosphors and fabricated a white-light LED device using Ce2CaF4S2:Tb3+ and blue-emitting commodity phosphors in combination of a 365 nm near-UV LED chip.