Improvement of the Water Resistance of a Narrow-Band Red-Emitting SrLiAl3N4:Eu2+ Phosphor Synthesized under High Isostatic Pressure through Coating with an Organosilica Layer

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• 作者：Dr. Yi-Ting Tsai ; Dr. Hoang-Duy Nguyen ; Dr. Agata Lazarowska ; Dr. Sebastian Mahlik ; Prof. Dr. Marek Grinberg and Prof. Dr. Ru-Shi Liu
• 刊名：Angewandte Chemie International Edition
• 出版年：2016
• 出版时间：August 8, 2016
• 年：2016
• 卷：55
• 期：33
• 页码：9652-9656
• 全文大小：2693K
• ISSN：1521-3773

文摘

A SrLiAl₃N₄:Eu²⁺ (SLA) red phosphor prepared through a high-pressure solid-state reaction was coated with an organosilica layer with a thickness of 400–600 nm to improve its water resistance. The observed 4f⁶5d→4f⁷ transition bands are thought to result from the existence of Eu²⁺ at two different Sr²⁺ sites. Luminescence spectra at 10 K revealed two zero-phonon lines at 15377 (for Eu(Sr1)) and 15780 cm⁻¹ (for Eu(Sr2)). The phosphor exhibited stable red emission under high pressure up to 312 kbar. The configurational coordinate diagram gave a theoretical explanation for the Eu^2+/3+ result. The coated samples showed excellent moisture resistance while retaining an external quantum efficiency (EQE) of 70 % of their initial EQE after aging for 5 days under harsh conditions. White-light-emitting diodes of the SLA red phosphor and a commercial Y₃Al₅O₁₂:Ce³⁺ yellow phosphor on a blue InGaN chip showed high color rendition (CRI=89, R9=69) and a low correlated color temperature of 2406 K.