Crystal structure and luminescence properties of Sr{sub}2Al{sub}6O{sub}11:Eu{sup}(2+)

摘要

Eu{sup}2+ activated Sr{sub}4 Al{sub}6 O{sub}11 and Sr{sub}4 Al{sub}14 O{sub}25 were prepared with B{sub}2O{sub}3 additives at the temperatures of 1100°C to 1300°C in flowing 5% H{sub}2/Ar gas. These products were characterized by XRD analysis, UV and VUV spectroscopy and so forth. The precise crystal structure of Sr{sub}2 Al{sub}6 O{sub}11 was first determined by Rietveld method. Between the sheets of the edge shared AlO{sub}6 octahedron, the corner shared AlO{sub}4 tetrahedral linkages of Sr{sub}2 Al{sub}6 O{sub}11 demonstrated a quite different fashion than that of Sr{sub}4 Al{sub}14 O{sub}25. According to the UV-Vis. and VUV spectra, an intense broad emission was observed near 460 nm in Sr{sub}2 Al{sub}6 O{sub}11: Eu{sup}2+, and two emission peaks were recognized at 409 nm and 496 nm in Sr{sub}4 Al{sub}4 O{sub}25: Eu{sup}2+. It was found that such emission profile and the thermal degradation of luminescence were fairly sensitive to every structural characteristic.