An intense blue emission of Eu2+-doped Ba5SiO4Cl6 under vacuum ultraviolet and near-ultraviolet excitation was observed. The material exhibits an emission peak at 440 nm with relative intensity 50% under 147 nm, 90% under 254 nm, 120% under 366 nm, and 220% under 405 nm excitation as compared with the commercial blue phosphor BaMgAl10O17:Eu2+. It is a very promising candidate as a blue-emitting phosphor for potential applications in display and light-emitting diode devices.

The luminescence properties of blue phosphors 0.9BaOÁ0.1EuOÁMgOÁmAl 2 O 3 with m ¼ 3:5 to 8.0 were investigated for color plasma display panel (PDP) applications. The deterioration properties of the phosphors baked in air and irradiated under vacuum ultraviolet (VUV) rays were systematically studied with different alumina contents m. The results indicate that the phosphor with m ¼ 5:0 shows a relatively more stable color chromaticity after the baking process and VUV irradiation, whereas the phosphors with m ¼ 5:5 to 8.0 show small decreases in the emission intensity compared to the phosphor with m ¼ 5:0 after VUV irradiation. These decreases in the emission efficiency are ascribed to the irregular order of the Eu 2þ ions in the intermediate layer and the shifts of the chromaticity coordinates to the changes of the Eu 2þ sites, which are suggested to occupy unstable Beevers-Ross and/or mid-oxygen sites in the host.

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Polymethylsilane PMS modified with titanium chloride TiCl 4 or molybdenum chloride MoCl 5 was pyrolyzed at various temperatures to enable a detailed investigation of stable phases formed during pyrolysis. The existence of TiSi 2 in PMS-TiCl 4 precursor and b-MoSi 2 in the PMS-MoCl 5 precursor below 1273 K suggested a strong interaction between Si-H and the metal chlorides during mixing. During pyrolysis of the PMS-10 massಚ TiCl 4 precursor, a silicon rich Si-Ti-C state was obtained below 973 K, which simultaneously formed crystalline Si, TiSi 2 , and SiC phases at relatively low temperatures below 1273 K. During pyrolysis of the PMS-MoCl 5 precursors, however, formation of crystalline Si and SiC phases were not accelerated, while the crystalline bMoSi 2 or a-MoSi 2 phase was formed rapidly.