TY  - JOUR
A1  - Muhr, V.
A1  - Würth, Christian
A1  - Kraft, Marco
A1  - Buchner, M.
A1  - Baeumner, A. J.
A1  - Resch-Genger, Ute
A1  - Hirsch, T.
T1  - Particle-size-dependent Förster resonance energy transfer from upconversion nanoparticles to organic dyes
JF  - Analytical Chemistry
N2  - Upconversion nanoparticles (UCNPs) are attractive candidates for energy transfer-based analytical applications. In contrast to classical donor−acceptor pairs, these particles contain many emitting lanthanide ions together with numerous acceptor dye molecules at different distances to each other, strongly depending on the particle diameter.
UCNPs with precisely controlled sizes between 10 and 43 nm were prepared and functionalized with rose bengal and sulforhodamine B by a ligand-exchange procedure. Timeresolved studies of the upconversion luminescence of the UCNP donor revealed a considerable shortening of the donor lifetime as a clear hint for Förster resonance energy transfer (FRET). FRET was most pronounced for 21 nm-sized UCNPs, yielding a FRET efficiency of 60%. At larger surface-to-volume ratios, the FRET efficiency decreased by an increasing competition of nonradiative surface deactivation. Such dye-UCNP architectures can also provide an elegant way to shift the UCNP emission color, since the fluorescence intensity of the organic dyes excited by FRET was comparable to that of the upconversion emission of smaller particles.
KW  - Upconversion
KW  - FRET
KW  - Organic dyes
PY  - 2017
DO  - https://doi.org/10.1021/acs.analchem.6b04662
SN  - 0003-2700
SN  - 1520-6882
VL  - 89
IS  - 9
SP  - 4868
EP  - 4874
PB  - ACS
AN  - OPUS4-40092
LA  - eng
AD  - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER  -