Discovery of the Persistent Luminescence Mechanism of CdSiO3:Tb3+

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• 作者：Lucas C.V. Rodrigues ; Hermi F. Brito ; Jorma H枚ls盲 ; Roberval Stefani ; Maria C.F.C. Felinto ; Mika Lastusaari ; Taneli Laamanen ; Luiz A.O. Nunes
• 刊名：The Journal of Physical Chemistry C
• 出版年：2012
• 出版时间：May 24, 2012
• 年：2012
• 卷：116
• 期：20
• 页码：11232-11240
• 全文大小：407K
• 年卷期：v.116,no.20(May 24, 2012)
• ISSN：1932-7455

文摘

The persistent luminescence of CdSiO₃:Tb³⁺ was investigated with photoluminescence, thermoluminescence (TL), synchrotron radiation X-ray absorption (XANES and EXAFS) and UV-VUV spectroscopies. Only the typical intraconfigurational 4f⁸鈥?f⁸ transitions of the Tb³⁺ ion were observed with no traces of band emission in either the conventional UV excited or persistent luminescence spectra. The trap structure from TL with three traps from 0.65 to 0.85 eV is ideal for room-temperature persistent luminescence similar to, e.g., Sr₂MgSi₂O₇:Eu²⁺,R³⁺. Despite the rather low band gap energy, 5.28 eV, the persistent luminescence from Tb³⁺ is produced only under UV irradiation due to the inauspicious position of the ⁷F₆ ground level deep in the band gap of CdSiO₃. This confirms the role of electrons as the charge carriers in the mechanism of Tb³⁺ persistent luminescence. The XANES spectra indicated the presence of only the trivalent Tb³⁺ species, thus excluding the direct Tb³⁺ 鈫?Tb^IV oxidation during the charging process of persistent luminescence. Eventually, a unique persistent luminescence mechanism for Tb³⁺ in CdSiO₃ was constructed based on the comprehensive experimental data.