The Structure And Spectrum Tuning Of A₃MgSi₂O₈:Eu²⁺,Mn²⁺（A=Ca, Sr, Ba）Phsophors For Led Via The Luminescence Of Mn²⁺

Based on the featured red-orange emissions of Mn2+in some specific host, near-ultraviolet (NUV) excitable magnesium silicates A3MgSi2O8(A=Ca, Sr, Ba):Eu2+, Mn2+phosphor were investigated and the prototypes of light emitting diodes (LEDs) were fabricated. Optimization of composition and crystallurgical structure, phosphors allow a610-640nm orange light emission which enable white LEDs (WLEDs) to be with high color rendering index (CRI), and660nm-fatured photosynthetic active spectrum which makes bio-lighting to be in high quantum yield. The results in this thesis will be helpful for the understanding of orange-red emission, luminescence of Mn2+, energy transfer and crysatllurgical structure of magnesium siliate, and provide important informations to develop warm white for illumination and display with orange-red of Mn2+and biolighting devices using inorganic silicate with doped Mn2+. The mian achievements in this study were summarized as follows.1. Single-phased (Ba, Sr)3MgSi2O8:Eu2+, Mn2+phosphor with660nm-featured dual band-emission was obtained in the absence of green emitting impurity phase. This dual broad band emission phosphor has a72nm full width at half maximum (FWHM) for red band and43nm FWHM for blue band. The emission spectrum covers fairly well to the absorption spectrum of chlorophyll and PAS for most plants.2. White light emission was achieved with a core-shell-like structured sphere by coating A2SiO4:Eu2+on A3MgSi2O8:Eu2+, Mn2+with610-640nm featured red band-emission of Mn2+. A high CRI of91with a CCT value of3630K, chromaticity coordinates (x=0.385, y=0.3443) of white light exhibit the potential application in warm WLEDs and display devices.3. The emission spectra, quantum efficiency, thermal stability relevant to varied composition of hosts such as Ba3MgSi2O8:Eu2+, Mn2+-Sr3MgSi2O8:Eu2+,Mn2+, Ba3MgSi2O8: Eu2+,Mn2+-Ca3MgSi2O8:Eu2+, Mn2+and Sr3MgSi208:Eu2+, Mn2+-Ca3MgSi2O8:Eu2+, Mn2+were investigated to optimize the orange-red emission of Mn2+. In particular, the relation of energy transfer mechanisms to quantum efficiency variation was examined.