%0 Journal Article
%T Enhanced Upconversion Luminescence in Yb3+/Tm3+-Codoped Fluoride Active Core/Active Shell/Inert Shell Nanoparticles through Directed Energy Migration
%A Hailong Qiu
%A Chunhui Yang
%A Wei Shao
%A Jossana Damasco
%A Xianliang Wang
%A Hans £¿gren
%A Paras N. Prasad
%A Guanying Chen
%J Nanomaterials
%D 2014
%I MDPI AG
%R 10.3390/nano4010055
%X The luminescence efficiency of lanthanide-doped upconversion nanoparticles is of particular importance for their embodiment in biophotonic and photonic applications. Here, we show that the upconversion luminescence of typically used NaYF 4:Yb 3+30%/Tm 3+0.5% nanoparticles can be enhanced by ~240 times through a hierarchical active core/active shell/inert shell (NaYF 4:Yb 3+30%/Tm 3+0.5%)/NaYbF 4/NaYF 4 design, which involves the use of directed energy migration in the second active shell layer. The resulting active core/active shell/inert shell nanoparticles are determined to be about 11 times brighter than that of well-investigated (NaYF 4:Yb 3+30%/Tm 3+0.5%)/NaYF 4 active core/inert shell nanoparticles when excited at ~980 nm. The strategy for enhanced upconversion in Yb 3+/Tm 3+-codoped NaYF 4 nanoparticles through directed energy migration might have implications for other types of lanthanide-doped upconversion nanoparticles.
%K upconversion
%K efficiency
%K core/shell
%K energy migration
%U http://www.mdpi.com/2079-4991/4/1/55