Dwivedi Y, Zilio S C
Instituto de Física de São Carlos, Universidade de São Paulo, CP 369, 13560-970 São Carlos, SP, Brazil.
Opt Express. 2013 Feb 25;21(4):4717-27. doi: 10.1364/OE.21.004717.
This work reports on the efficient cooperative upconversion and infrared cascade downconversion emissions in a novel Y₈V₂O₁₇:Eu:Yb nanophosphor. The excitation with UV light produces emission in the 950-1000 nm region, corresponding to the Yb³⁺:²F₅/₂-->²F₇/₂ transition, as well as visible emissions of the Eu³⁺ ion. Time-resolved spectroscopy measurements revealed that the mechanism responsible for this transition is the efficient cascade nonresonant energy transfer from VO₄³-->Eu-->Yb. When the same nanophosphor is excited with 976 nm radiation, bright reddish upconversion emission of the Eu³⁺:⁵DJ-->⁷FJ transition is observed as consequence of the Yb + Yb-->Eu cooperative energy transfer mechanism, which was established by analyzing the emission power dependence and the time-resolved spectroscopy of radiative transitions.
这项工作报道了一种新型Y₈V₂O₁₇:Eu:Yb纳米磷光体中的高效合作上转换和红外级联下转换发射。用紫外光激发会在950 - 1000 nm区域产生发射，对应于Yb³⁺:²F₅/₂-->²F₇/₂跃迁，以及Eu³⁺离子的可见发射。时间分辨光谱测量表明，负责这种跃迁的机制是从VO₄³⁻-->Eu-->Yb的高效级联非共振能量转移。当用976 nm辐射激发相同的纳米磷光体时，由于Yb + Yb-->Eu合作能量转移机制，观察到Eu³⁺:⁵DJ-->⁷FJ跃迁的明亮红色上转换发射，这是通过分析发射功率依赖性和辐射跃迁的时间分辨光谱确定的。
