Oxygen-Vacancy-Induced Midgap States Responsible for the Fluorescence and the Long-Lasting Phosphorescence of the Inverse Spinel Mg(Mg,Sn)O4

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• 作者：Gaganpreet Kaur Behrh ; Masahiko Isobe ; Florian Massuyeau ; Hélène Serier-Brault ; Elijah E. Gordon ; Hyun-Joo Koo ; Myung-Hwan Whangbo ; Romain Gautier ; Stéphane Jobic
• 刊名：Chemistry of Materials
• 出版年：2017
• 出版时间：February 14, 2017
• 年：2017
• 卷：29
• 期：3
• 页码：1069-1075
• 全文大小：484K
• ISSN：1520-5002

文摘

Samples of inverse spinel Mg₂SnO₄ were prepared using a ceramic method, their phosphorescence phenomenon was probed by optical measurements, and its cause was explored on the basis of density functional theory calculations for model structures of Mg₂SnO₄ with oxygen vacancies V_O. Mg₂SnO₄ exhibits long-lasting luminescence at two different wavelength regions, peaking at ∼498 and ∼755 nm. A Sn-V_O-Sn defect plus a Mg vacancy V_Mg away from the V_O generates the empty midgap states, σ_Sn-Sn and σ_Sn-Sn^*, localized at the Sn-V_O-Sn defect, while an oxygen vacancy V_O between adjacent Sn⁴⁺ and Mg²⁺ sites creates a filled midgap state Sn²⁺ (5s² lone pair) lying below the σ_Sn-Sn level. The long-lasting luminescence at two different wavelength regions and the up-conversion photostimulated luminescence observed for undoped Mg₂SnO₄ are well explained by considering the σ_Sn-Sn^* level as the trapping level for a photogenerated electron.