新穎氯矽硫、鹵鎵硫及鋁酸鹽螢光體之合成、特性鑑定及其於白光發光二極體之應用

Abstract

利用藍光或近紫外光晶片搭配螢光粉以封裝白光發光二極體為下世代照明發展的主要課題之一。本研究利用固態合成法成功製備Ce3+激活之La3S2Cl(SiS4):Ce3+鹵矽硫化物螢光體與Eu2+激活之Sr6Y2Al4O15:Eu2+鋁酸鹽、Ba3GaS4Cl:Eu2+及Ba3GaS4Br:Eu2+等鹵鎵硫化物。我們利用粉末X光繞射、螢光光譜議、場發射掃瞄式電子顯微鏡探討上述螢光體之合成條件、活化劑最佳摻雜濃度，同時亦測量其激發與放射光譜、CIE色度座標、量子效率與熱消光光譜，並進一步將所製備之螢光體應用於白光LED的封裝。 本論文所合成之Ce3+或Eu2+摻雜螢光體，激發波段在近紫外光至藍光範圍，放射波長則介於470 nm至518 nm波段範圍，適合搭配不同波長之LED晶片並封裝為白光發光二極體。 本研究第一部份探討不同主體螢光粉之最佳製程條件與粉末X光繞射晶相之分析鑑定，第二部份則探討Ce3+摻雜螢光體發光特性，第三部份研究Eu2+摻雜螢光體之發光特性，第四部份則探討不同螢光體之熱消光光譜並研究其原因，最終則將所合成之螢光材料應用於白光發光二極體的封裝。

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. We have screened and selected the chlorothiosilicates, halotiogallate, and aluminate as host materials, which were activated with Ce3+ or Eu2+ as activator, respectively. In this research, we have successfully synthesized four novel rare earth+-activated phosphors, La3S2Cl(SiS4):Ce3+, Sr6Y2Al4O15:Eu2+, Ba3GaS4Cl:Eu2+ and Ba3GaS4Br:Eu2+ by using solid-state method or solid-sate reaction in evacuated sealed quarz glass tubes. In this study, the excitation band of four Ce3+- or Eu2+ - doped phosphors are in the range of near-UV to blue, and the emission wavelength are in the visible range located in the range between 470 nm to 510 nm,. It is suitable for fabrication of white-light emitting diodes (WLED). We have also investigated the optimization of synthetic conditions for all phosphors and the phase analysis using X-ray diffraction. The phosphors were further characterized by photoluminescence spectroscopy and electron microscopy to investigate their luminescence, microstructures, chromaticity, quantum efficiency and thermal quenching behaviors. Finally, we dicussed fabrication of white-light LEDs by using the phosphors we synthesized in combination with respective LED chips.