The effect of surface coating on energy migration-mediated upconversion.
J Am Chem Soc
; 134(51): 20849-57, 2012 Dec 26.
Article
em En
| MEDLINE
| ID: mdl-23210614
ABSTRACT
Lanthanide-doped upconversion nanoparticles have been the focus of a growing body of investigation because of their promising applications ranging from data storage to biological imaging and drug delivery. Here we present the rational design, synthesis, and characterization of a new class of core-shell upconversion nanoparticles displaying unprecedented optical properties. Specifically, we show that the epitaxial growth of an optically inert NaYF(4) layer around a lanthanide-doped NaGdF(4)@NaGdF(4) core-shell nanoparticle effectively prevents surface quenching of excitation energy. At room temperature, the energy migrates over Gd sublattices and is adequately trapped by the activator ions embedded in host lattices. Importantly, the NaYF(4) shell-coating strategy gives access to tunable upconversion emissions from a variety of activators (Dy(3+), Sm(3+), Tb(3+), and Eu(3+)) doped at very low concentrations (down to 1 mol %). Our mechanistic investigations make possible, for the first time, the realization of efficient emissions from Tb(3+) and Eu(3+) activators that are doped homogeneously with Yb(3+)/Tm(3+) ions. The advances on these luminescent nanomaterials offer exciting opportunities for important biological and energy applications.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Ítrio
/
Elementos da Série dos Lantanídeos
/
Substâncias Luminescentes
/
Nanopartículas
/
Fluoretos
Limite:
Humans
Idioma:
En
Revista:
J Am Chem Soc
Ano de publicação:
2012
Tipo de documento:
Article
País de afiliação:
Singapura