Versatile Ca4F2Si2O7 Host from Defect-Induced Host Emission to White-Light-Emitting Ce3+-Doped Ca4F2Si2O7 Phosphor for Near-UV Solid-State Lighting

详细信息    查看全文

• 作者：Paulraj Arunkumar ; Yoon Hwa Kim ; Won Bin Im
• 刊名：Journal of Physical Chemistry C
• 出版年：2016
• 出版时间：March 3, 2016
• 年：2016
• 卷：120
• 期：8
• 页码：4495-4503
• 全文大小：510K
• ISSN：1932-7455

文摘

White-light-emitting Ca_4–xF₂Si₂O₇:xCe³⁺ phosphor and violet-light-emitting oxyfluoride Ca₄F₂Si₂O₇ host were synthesized by solid-state reaction. Ca_4–xF₂Si₂O₇:xCe³⁺ has strong absorption in the near-UV region (370 nm) and shows a broad emission in the range of 390–600 nm centered at 475 nm. Under 315 nm excitation, a narrow blue emission was observed. The Ca₄F₂Si₂O₇ host synthesized under the same reduction conditions exhibited violet emission due to the formation of anion-deficient nonstoichiometric Ca₄F_2−δSi₂O_7+δ/2 species. The broad emission of Ca₄F₂Si₂O₇:xCe³⁺ phosphor is attributed to Ce³⁺ occupying two crystallographic calcium sites available in the host. A white LED device was fabricated using Ca₄F₂Si₂O₇:Ce³⁺ without any additive phosphor, displaying excellent CIE chromaticity (0.29, 0.35) close to white emission with a color rendering index of 97. These exceptional optical properties of Ca₄F₂Si₂O₇:Ce³⁺ suggest the promising application of the single activator phosphor that could produce white light under near-UV-based LEDs.