Publications

In-Depth Analysis of Excitation Dynamics in Dye-Sensitized Upconversion Core and Core/Active Shell Nanoparticles

Journal of Physical Chemistry C 2018, 122(31), 18177–18184

Abstract

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 non-sensitized 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 non-sensitized UCNPs. For dye-sensitized UCNPs, the fast, sub-microsecond component of the upconversion luminescence rise time is attributed to radiative pumping of Er³⁺ ions from the dye, while the slow, sub-millisecond component is due to non-radiative energy transfer from the dye predominantly to Yb³⁺ ions, followed by energy migration and non-radiative energy transfer from Yb³⁺ to Er³⁺ ions. Our studies provide insight into the interplay between radiative and non-radiative energy transfer as well as the role of energy migration across the active shell of dye-sensitized core/active shell UCNPs.

For citation:
Alyatkin, S.; Urena Horno, E.; Chen, B.; Muskens, O. L.; Kanaras, A. G.; Lagoudakis, P. G.
"In-Depth Analysis of Excitation Dynamics in Dye-Sensitized Upconversion Core and Core/Active Shell Nanoparticles"
J. Phys. Chem. C 2018, 122(31), 18177–18184

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