Luminescence Mechanism and Thermal Stabilities of a White Silicate Phosphor for Multifunctional Applications

A series of Dy³⁺‐doped Sr_2(1?y)Ca_2yY₈(SiO₄)₆O₂ (0 ≤ y ≤ 1) white phosphors were synthesized by the solid‐state reaction. All samples crystallize into a hexagonal crystal system with space group P6₃/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.