Energy Migration Up-conversion of Tb3+ in Yb3+ and Nd3+ Codoped Active-Core/Active-Shell Colloidal Nanoparticles

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• 作者：Katarzyna Prorok ; Mirosława Pawlyta ; Wiesław Stręk ; Artur Bednarkiewicz
• 刊名：Chemistry of Materials
• 出版年：2016
• 出版时间：April 12, 2016
• 年：2016
• 卷：28
• 期：7
• 页码：2295-2300
• 全文大小：441K
• 年卷期：0
• ISSN：1520-5002

文摘

The intentional design of chemical architecture of lanthanide doped luminescent nanoparticles through the proper selection of dopants in core–shell and core–shell–shell structures enables optimization of their optical properties. Such an approach allows one to achieve energy transfer up-conversion (ETU) and energy migration mediated up-conversion (EMU) and green emission from Tb³⁺ ions with the Yb³⁺ and Nd³⁺ sensitizers at 980 and 808 nm photoexcitation, respectively. The [Nd³⁺ → Yb³⁺]→ [Yb³⁺ → Tb³⁺] EMU phenomenon was significantly enhanced by spatial displacement of the sensitizing Nd³⁺ ions from the activator Tb³⁺ ions by intentionally introducing an intermediate Yb³⁺ sensitizer layer forming a [Nd³⁺ → Yb³⁺] → [Yb³⁺] → [Yb³⁺ → Tb³⁺] system. Otherwise Tb³⁺ emission was considerably quenched by Nd³⁺ ions even though they were spitted between the core and shell, respectively. Moreover, (Tb³⁺,Yb³⁺) → (Tb⁴⁺,Yb²⁺) valence change has been discovered to limit the Tb³⁺ up-conversion emission. The studies explain how the chemical architecture of the smartly designed active-core @ active-shell luminescent nanoparticles may improve their spectral properties.