Photoluminescent Layered Lanthanide Silicates

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• 作者：Duarte Ananias ; Mariya Kostova ; Filipe A. Almeida Paz ; Artur Ferreira ; Luí ; s D. Carlos ; Jacek Klinowski ; and Joã ; o Rocha
• 刊名：Journal of the American Chemical Society
• 出版年：2004
• 出版时间：August 25, 2004
• 年：2004
• 卷：126
• 期：33
• 页码：10410 - 10417
• 全文大小：282K
• 年卷期：v.126,no.33(August 25, 2004)
• ISSN：1520-5126

文摘

The hydrothermal synthesis and structural characterization of layered lanthanide silicates,K₃[M_1-aLn_aSi₃O₈(OH)₂] (M = Y³⁺, Tb³⁺; Ln = Eu³⁺, Er³⁺, Tb³⁺, and Gd³⁺), named AV-22 materials, arereported. The structure of these solids was elucidated by single-crystal (180 K) and powder X-ray diffractionand further characterized by chemical analysis, thermogravimetry, scanning electron microscopy, ²⁹Si MASNMR, and photoluminescence spectroscopy. The Er-AV-22 material is a room-temperature infraredphosphor, while Tb- and Eu-AV-22 are visible emitters with output efficiencies comparable to standardsused in commercial lamps. The structure of these materials allows the inclusion of a second (or even athird) type of Ln³⁺ ion in the framework and, therefore, the fine-tuning of their photoluminescent properties.For the mixed Tb³⁺/Eu³⁺ materials, evidence has been found of the inclusion of Eu³⁺ ions in the interlayerspace by replacing K⁺ ions, further allowing the activation of Tb³⁺-to-Eu³⁺ energy transfer mechanisms.The occurrence probability of such mechanisms ranges from 0.62 (a = 0.05) to 1.20 ms^-1 (a = 0.1) witha high energy transfer efficiency (0.73 and 0.84, respectively).