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

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• 作者：Qisheng Sun ; Xuemin Li ; Yide Du ; Bo Zhao ; Hua Li ; Yan Huang ; Zhipeng Ci ; Jiachi Zhang ; Ji Ma and Yuhua Wang
• 刊名：Journal of the American Ceramic Society
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：100
• 期：1
• 页码：193-203
• 全文大小：2664K
• ISSN：1551-2916

文摘

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.