TY - CONF A1 - Resch-Genger, Ute A1 - Wuerth, Christian A1 - Kraft, Marco A1 - Kaiser, Martin A1 - Radunz, Sebastian A1 - Muhr, V. A1 - Hirsch, Th. A1 - Soukka, T. A1 - Homann, C. A1 - Haase, M. T1 - Luminescence efficiency of upconversion – Quantification of size, particle architecture and dopant concentration effects for different excitation power densities N2 - Lanthanide-based upconversion nanoparticles (UCNPs)like hexagonal beta-NaYF4 UCNPs doped with Yb3+ and Er3+, which efficiently convert 976 nm light to ultraviolet, visible, and near infrared photons, offer new strategies for luminescence-based sensing and imaging. The properties of their upconversion (UC) luminescence (UCL) are, however, strongly influenced by particle size, concentration and spatial arrangement of dopant ions, surface chemistry, microenvironment, and excitation power density (P). We present here comprehensive studies of the influence of UCNP size and particle architecture for Yb3+ and Er3+ co-doped NaYF4 nanoparticles and energy transfer processes in these materials, which underline the importance of quantitative luminescence measurements for mechanistic insights and the determination of application-relevant matrix- and P-dependent optimum dopand concentrations. T2 - 2nd Conference and Spring School CY - Valencia, Spain DA - 04.04.2018 KW - Upconverting nanoparticles KW - Size KW - Energy transfer KW - Fluorescence KW - Absolute fluorescence quantum yield KW - Fluorescence decay kinetics KW - Power density dependence PY - 2018 AN - OPUS4-44960 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -