Rapid microwave preparation of cerium-substituted sodium yttrium silicate phosphors for solid state white lighting

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• 作者：Jakoah Brgoch ; Christopher K.H. Borg ; Kristin A. Denault ; Jasmine R. Douglas ; T. Am ; a Strom ; Steven P. DenBaars ; Ram Seshadri
• 关键词：Phosphors ; Solid-state lighting ; Microwave preparation ; Sodium yttrium silicate
• 刊名：Solid State Sciences
• 出版年：December, 2013
• 年：2013
• 卷：26
• 期：Complete
• 页码：115-120
• 全文大小：1530 K

文摘

The preparation of two cerium-substituted sodium yttrium silicate phosphors, NaY₉Si₆O₂₆:Ce³⁺ and Na₃YSi₂O₇:Ce³⁺, was achieved using rapid heating via a modified microwave-assisted preparation technique. Activated carbon is used as a microwave susceptor allowing reaction temperatures greater than 1000聽掳C to be reached in minutes while producing the reducing atmosphere necessary to achieve Ce³⁺. Because this method immediately heats the sample and does not employ a H₂/N₂ gas mixture to maintain Ce³⁺ in its reduced state, volatilization of starting materials is limited, allowing the products to be prepared from a stoichiometric mixture of starting materials. The samples prepared were characterized using synchrotron X-ray powder diffraction and fluorescence spectroscopy. Photoluminescence measurements indicate NaY₉Si₆O₂₆:Ce³⁺ contains a broad excitation band in the UV ranging between 280聽nm and 330聽nm that produces a blue emission between 350聽nm and 500聽nm with a 10% quantum yield. Na₃YSi₂O₇:Ce³⁺ has a strong absorption band at 350聽nm and also emits in the blue (375聽nm-500聽nm) with a quantum yield of 28%.