| 研究実績の概要 |
I.
Atomic scale origin of moisture resistance and thermal quenching for (Ba,Sr)3SiO5:Eu2+ was investigated. The moisture induced degradation was evaluated by the powder X-ray diffraction and photoluminescence (PL) emission. The crystal structure and electron distribution was analyzed by Rietveld refinement and density functional theory (DFT) calculation. It is found that the dispersion of electrons is relevant to effective collision and then the stability of the host lattice. Furthermore, Voronoi-Dirichilet polyhedron (VDP) is put forward to evaluate the spacial influence on the dispersion of electrons by the surrounding ions. Finally, we correlated global instability index (GII) to the lattice vibration induced thermal quenching, suggesting the significance of thermodynamic for phosphor hosts.
II.
A new ABC4(O,N)7-type oxynitride phosphor SrLuAl2Si2O2N5 is reported. The phosphors were synthesized by conventional solid state method. The crystal structure was confirmed by X-ray diffraction. The luminescence properties doping Ce3+ and Eu2+ were investigated by photoluminescence spectra. The thermal degradation was analyzed by thermogravimetric different thermal analysis (TG-DTA) and oxygen/nitrogen analysis. The performance of the phosphors was characterized by quantum efficiency and thermal quenching tests.
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