LAUSR

A series of Dy3+-doped Sr2(1-y)Ca2yY8(SiO4)(6)O-2 (0 y 1) white phosphors were synthesized by the solid-state reaction. All samples crystallize into a hexagonal crystal system with space group P6(3)/m (176) by the determination of XRD Rietveld refinements. With the change in Ca/Sr ratio, the crystal environment of active ions is lightly affected. Upon excitation by UV/VUV/cathode ray sources, the samples present an efficient white light emission with significant differences in the blue/yellow ratio of Dy3+ characteristic transitions. Based on luminescence properties, decay times and thermal properties, the interesting phenomenon with excitation energy increasing from UV to electron beam can be reasonably explained by a potential mechanism we proposed. With the introduction of Bi3+, the white emission intensity is rapidly enhanced and the optimal intensity reaches to 3.75 times compared with the single doped Dy3+ sample. To evaluate the applicability of this phosphor, we packaged two light-emitting diode devices and measured the actual luminescence efficacies and CIE chromaticity coordinates. These results indicate that the silicate phosphors have the potential for multifunctional application in ultraviolet-based light-emitting diodes, mercury-free lamps, and field-emission displays.