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 - TY - CONF A1 - Resch-Genger, Ute A1 - Nirmalananthan-Budau, Nithiya A1 - Moser, Marko A1 - Geißsler, Daniel A1 - Behnke, Thomas A1 - Schneider, Ralf T1 - Simple and versatile methods for quantifying functional groups, ligands, and biomolecules on nanomaterials N2 - Many applications of nanomaterials in the life sciences require the controlled functionalization of these materials with ligands like polyethylene glycol (PEG) and/or biomolecules such as peptides, proteins, and DNA. This enables to tune their hydrophilicity and biocompatibility, minimize unspecific interactions, improve biofunction-nalization efficiencies, and enhance blood circulation times and is the ultimate prerequisite for their use as reporters in assays or the design of targeted optial probes for bioimaging. At the core of these functionalization strategies are reliable and validated methods for surface group and ligand quantification that can be preferably performed with routine laboratory instrumentation, require only small amounts of substances, and are suitable for many different types of nanomaterials. We present here versatile and simple concepts for the quantification of common functional groups, ligands, and biomolecules on different types of organic and inorganic nano-materials, using different types of optical reporters and method validation with the aid of multimodal reporters and mass balances. T2 - RSC Symposium on Nanoparticle concentration – critical needs and state-of-the-art measurement CY - London, UK DA - 24.04.2018 KW - PEG ligands KW - Surface group analysis KW - Upconverting nanoparticles KW - Integrating sphere spectroscopy KW - Absolute fluorescence quantum yield KW - Fluorescence decay kinetics PY - 2018 N1 - Geburtsname von Nirmalananthan-Budau, Nithiya: Nirmalananthan, N. - Birth name of Nirmalananthan-Budau, Nithiya: Nirmalananthan, N. AN - OPUS4-44986 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute A1 - Würth, Christian A1 - Kraft, Marco A1 - Kaiser, Martin A1 - Grauel, Bettina A1 - Krukewitt, Lisa A1 - Frenzel, Florian A1 - Hirsch, T. A1 - Homann, C. A1 - Haase, M. A1 - Fischer, S. T1 - Quantification of Parameters Affecting the Upconversion Luminescence of Lanthanide-Based Upconversion Nanocrystals 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, barcoding, and imaging. The properties of their upconversion (UC) luminescence (UCL) are, however, strongly influenced by particle size, the concentration and spatial arrangement of the dopant ions, surface chemistry including presence and thickness of surface passivation and shielding shells, microenvironment/presence of quenchers with high energy vibrations, and excitation power density (P). We present here a comprehensive study of the influence of UCNP size and particle architecture for Yb3+ and Er3+ co-doped NaYF4 core-only and core-shell nanostructures in the size range of about 5 nm to 50 nm, which underlines the importance of particle synthesis, surface chemistry, and quantitative luminescence measurements for mechanistic insights and the determination of application-relevant matrix- and P-dependent optimum dopand concentrations. T2 - Materials Challenges in Alternative and Renewable Energy (MCARE) 2018 CY - Vancouver, BC, Canada DA - 20.08.2018 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 - OPUS4-46393 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -