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Sarkar S, Meesaragandla B, Hazra C, Mahalingam V.
Adv Mater.2013 Feb 13;25(6):856-60.
Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER-Kolkata), Mohanpur Campus, Nadia, WB 741252, India.
Abstract
The upconversion process is reported to occur via interparticle energy transfer (IPET) achieved with Ln(3+) -doped BaLuF(5) (Ln = Tm and Yb) nanocrystals in the size range of sub 5 nm. Both Yb(3+) and Tm(3+) ions are independently doped in BaLuF(5) nanocrystals. Colloidal mixtures containing the above two nanocrystals show strong upconversion emission in the blue, red, and near-IR regions via IPET.
Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Figure Legend
The above cartoon depicts the feasibility of the energy transfer process between donor (Yb3+) and acceptor (Tm3+) ions independently doped in two different nanocrystals leading to the upconversion luminescence. This is possible when the size of the nanocrystals is less than 5 nm and the distance between the two nanocrystals falls well within the FRET distance. Under this condition, exciting the donor with a 980 nm laser leads to blue emission from the acceptor nanoparticles presumably via a three photon process.
