In-Depth Analysis of Excitation Dynamics in Dye-Sensitized Upconversion Core and Core/Active Shell Nanoparticles
In-Depth Analysis of Excitation Dynamics in Dye-Sensitized Upconversion Core and Core/Active Shell Nanoparticles
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DOI：
10.1021/acs.jpcc.8b05992
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发表时间：
2018-08-09
影响因子：
3.7
通讯作者：
Lagoudakis, Pavlos G.
中科院分区：
文献类型：
--
作者：
Alyatkin, Sergey;Urena-Horno, Elena;Lagoudakis, Pavlos G.
结合染料敏化和核/壳增强的上转换纳米颗粒（UCNPs）由于其能够提高上转换系统的激发效率而引起极大兴趣。在这里，我们报告和调查20倍的上转换发光增强染料敏化的核心/活性壳UCNPs相比，在非敏化的核心只有UCNPs。我们观察到的染料敏化UCNPs的上转换动力学中的两个组件的发光上升动力学，明显不同的非敏化UCNPs的单组件上升动力学。对于染料敏化的UCNPs，上转换发光上升时间的快亚微秒分量归因于Er 3+离子从染料的辐射泵浦，而慢亚毫秒分量归因于从染料主要到Yb 3+离子的非辐射能量转移，随后是能量迁移和从Yb 3+到Er 3+离子的非辐射能量转移。我们的研究提供了一个深入了解辐射和非辐射能量转移之间的相互作用，以及到染料敏化核/活性壳UCNP的活性壳的能量迁移的作用。
Upconversion nanoparticles (UCNPs) combining both dye sensitization and core/shell enhancement are of great interest for their ability to boost the excitation efficiency of upconversion systems. Here, we report and investigate a 20-fold upconversion luminescence enhancement in dye-sensitized core/active shell UCNPs compared to that in nonsensitized core-only UCNPs. We observe a two-component luminescence rise dynamics in the upconversion kinetics of dye-sensitized UCNPs, distinctly different from the one-component rise dynamics of the nonsensitized UCNPs. For dye-sensitized UCNPs, the fast sub-microsecond component of the upconversion luminescence rise time is attributed to the radiative pumping of Er3+ ions from the dye, whereas the slow sub-millisecond component is due to the nonradiative energy transfer from the dye predominantly to Yb3+ ions, followed by the energy migration and the nonradiative energy transfer from Yb3+ to Er3+ ions. Our studies provide an insight into the interplay between radiative and nonradiative energy transfer as well as into the role of energy migration across the active shell of dye-sensitized core/active shell UCNPs.