新穎硫矽、硫氧與磷酸鹽螢光體之合成及特性鑑定與其在白光發光二極體之應用

Abstract

為發掘化學組成新穎之白光發光二極體螢光粉，本研究利用固態合成法成功製備Ce3+與Eu2+激活之Ba2Mg(PO4)2與SrMg2(PO4)2磷酸鹽、La10S14O硫氧化物與ZnY6Si2S14與BaGa2SiS6硫矽化物螢光體。進一步利用X光繞射、螢光光譜、電子顯微鏡術以探討上述螢光粉的最佳合成條件、最優化活化劑摻雜濃度、溫度依存熱消光光譜測定與色座標值。 本論文第一部分探討不同組成螢光體之最佳製程與X光繞射晶相之分析鑑定；第二部分探討Ce3+所摻雜螢光體之發光特性；第三部分研究Eu2+摻雜螢光體之發光特性；第四部分則探討不同螢光體的熱消光效應，並對熱消光原因進行探討。 本論文中，Ce3+或Eu2+摻雜之螢光體，激發波長涵蓋200 nm至600 nm，而放射波長則由337 nm紫外光至624 nm橙光，幾乎涵蓋了整個可見光範圍，其中磷酸鹽螢光粉激發波長都遠短於400 nm，不適合用於白光LED封裝；而硫化物主體的螢光粉因共價性較高，所以激發波長較長，適合用於白光發光二極體封裝。

White light-emitting diodes (LEDs) are considered to be the next generation of solid-state lighting systems because of their excellent properties, such as high efficiency, low power consumption, long life time, and environmental friendliness. We have screened and selected the phosphate, oxysulfide, and thiosilicates as host matrices, which were activated with Ce3+ or Eu2+ as activator, respectively. In this study, we have synthesized several new Ce3+ or Eu2+- activated phosphors with Ba2Mg(PO4)2, SrMg2(PO4)2, La10S14O, ZnY6Si2S14 and BaGa2SiS6 serving as hosts by using solid-state method. We have also reported the optimization of synthetic conditions for all phosphors and the analysis results using XRD. The phosphors were further characterized photoluminescence spectroscopy and thermal luminescence quenching measurements. Finally, we evaluate the potential applications of all phosphors by fabrication of white-light LEDs using BaGa2SiS6:Eu2+ and commodity phosphors in combination with a near-UV LED chip.