TY - JOUR A1 - Stroyuk, O. A1 - Raievska, O. A1 - Barabash, A. A1 - Batentschuk, M. A1 - Osvet, A. A1 - Fiedler, Saskia A1 - Resch-Genger, Ute A1 - Hauch, J. A1 - Brabec, C. J. T1 - “Green” Synthesis of Highly Luminescent Lead-Free Cs2AgxNa1-xBiyIn1-yCl6 Perovskites JF - Journal of Materials Chemistry C N2 - A new “green” and mild synthesis of highly stable microcrystalline Cs2AgxNa1-xBiyIn1-yCl6 (CANBIC) perovskites under ambient conditions was developed that is scalable to the multi-gram production. Under UV illumination, the CANBIC perovskites emit intense broadband photoluminescence (PL) with a quantum yield (QY) of 92% observed for x = 0.35 and y = 0.01-0.02. The combination of strong UV absorbance and broadband visible emission, high PL QY, and long PL lifetimes of up to 1.4 μs, along with an outstanding stability makes these CANBICs a promising material class for many optical applications. KW - Fluorescence KW - Perovskites KW - Solar cell KW - Automated synthesis KW - Green synthesis KW - Quantum yield KW - Integrating sphere spectroscopy KW - Absolute fluorescence KW - Quality assurance KW - Nano KW - Particle KW - Application KW - Semiconductor KW - Quantum dot KW - Renewable energy PY - 2022 DO - https://doi.org/10.1039/d2tc02055f SN - 2050-7526 VL - 10 IS - 27 SP - 9938 EP - 9944 PB - Royal Society of Chemistry AN - OPUS4-55453 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute A1 - Würth, Christian A1 - Frenzel, Florian A1 - Grauel, Bettina A1 - Nirmalananthan-Budau, Nithiya A1 - Pauli, Jutta A1 - Hoffmann, Katrin T1 - Photoluminescence at BAM – Photoluminescence at BAM – Photophysical Studies, Quantum Yield Measurements, Multiplexing Strategies, and Standards N2 - Photoluminescence applications in the life and material sciences require bright molecular and nanocrystalline emitters, stimuli-responsive optical probes, signal enhancement, multiplexing, and barcoding strategies and traceable methods to quantify the signal-relevant optical properties of luminescent materials at the ensemble and single molecule/particle level. In this context, current research at Division Biophotonics of BAM is presented ranging from dye and nanocrystal photophysics, absolute measurements of photoluminescence quantum yields in the UV/vis/NIR/SWIR, lifetime multiplexing, and the development of different types of fluorescence standards for validating optical-spectroscopic measurements. T2 - Institutskolloquium IPHT CY - Jena, Germany DA - 22.10.2019 KW - Surface group analysis KW - NIR KW - SWIR KW - Quantum dot KW - Lanthanide KW - Cleavable probe KW - Lifetime KW - Multiplexing KW - Sensor KW - Assay PY - 2019 AN - OPUS4-49360 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute T1 - Advanced characterization of nanomaterials N2 - The rational synthesis and use of nanomaterials require the characterization of many different properties, ranging from particle size and size distribution over surface chemistry to more applicationrelevant features like optical, electrochemical, and magnetic properties. In the following, several methods for the characterization of functional groups on nanomaterials, like polymer and silica nanoparticles, semiconductor quantum dots, and lanthanide-based upconversion nanocrystals are presented. Additionally, procedures for the measurement of the key spectroscopic performance parameters of nanomaterials with linear and nonlinear photoluminescence, such as the photoluminescence quantum yield, are presented for the UV/vis/NIR/SWIR. T2 - Summerschool CY - Bad Honnef, Germany DA - 22.07.2019 KW - Quantum yield KW - Nanoparticle KW - Fluorescence KW - Quantum dot KW - NIR KW - SWIR KW - Quality assurance KW - Calibration PY - 2019 AN - OPUS4-48630 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute A1 - Pauli, Jutta A1 - Würth, Christian A1 - Güttler, Arne A1 - Richter, Maria A1 - Schneider, Thomas T1 - Determining Photoluminescence Quantum Yields of Molecular and Nanocrystal Emitters in the UV/vis/NIR/SWIR N2 - The comparison of different emitter classes and the rational design of the next generation of molecular and nanoscale reporters require accurate and quantitative photo-luminescence measurements. This is of special importance for all photoluminescence applications in the life and material sciences and nanobiophotonics. In the following, procedures for the determination of the spectroscopic key parameter photoluminescence quantum yield, i.e., the number of emitted per absorbed photons, in the UV/vis/NIR/SWIR are presented including pitfalls and achievable uncertainties and material-specific effects related to certain emitter classes are addressed. T2 - Kolloqium National Center for Nanoscience and Technology CY - Peking, People's Republic of China DA - 18.10.2019 KW - Fluorescence KW - Quantum yield KW - Integrating sphere spectroscopy KW - Dye KW - Nanocrystal KW - NIR KW - SWIR KW - Quantum dot KW - Fluorescence standard KW - Uncertainty KW - Calibration PY - 2019 AN - OPUS4-49362 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hübner, Oskar A1 - Resch-Genger, Ute T1 - Spectral and Lifetime Encoding of Polymer Particles with Cd-free Ternary Semiconductor Nanocrystals for Flow Cytometry with Time Resolved Fluorescence Detection N2 - Multiplexed encoding schemes of nano- and micrometer sized particles with fluorescent dyes or quantum dots (QDs) and their optical detection, are of increasing interest for applications in the life sciences, for example in flow cytometry. Almost all strategies utilizing fluorescence focus on spectrally distinguishable emission bands or colors and different intensity levels as fluorescence codes. The fluorescence parameter lifetime has been, however, barely exploited. In this work the goal is to perform multiplexing with encoding fluorophores with different fluorescence lifetimes (LTs). In comparison to the spectral multiplexing strategies this has the advantage, that the different fluorescence LT codes can be measured with the excitation and emission wavelength, thus reducing instrument costs. Moreover, LTs should not depend on emitter concentration. Unlike organic dyes, the LTs of which are typically < 10 ns, the fluorescence LTs of ternary semiconductor QDs that represent a “green” alternative to conventional Cd-containing QDs are in the range of several hundred ns, independent of oxygen concentration, and can be tuned to a certain extent by chemical composition and surface chemistry. This present a time region that can be barely covered by other emitters that have either much shorter or longer lifetimes. In this project, different encoding strategies will be assessed and the encoded particles will be then used for fluorescence assays for the analysis of several targets in parallel. Therefor the encoded particles will be functionalized with different target-specific bioligands and read out with a specifically designed flow cytometer enabling time-resolved fluorescence detection. With this instrument, the particles will be discriminated by their fluorescence LTs In one detection channel while the analytes will be quantified by fluorescence labels in a second channel in the intensity domain. T2 - Bad Honnef Physics School Exciting nanostructures: Characterizing advanced confined systems CY - Bad Honnef, Germany DA - 21.07.2019 KW - Multiplexing KW - Lifetime KW - Bead KW - Flow cytometry KW - Fluorescence KW - Quantum dot KW - InP KW - AIS KW - Dye KW - Encoding KW - Barcoding KW - Assay KW - Method PY - 2019 AN - OPUS4-49723 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute A1 - Weigert, Florian A1 - Frenzel, Florian A1 - Würth, Christian A1 - Hoffmann, Katrin A1 - Martynenko, Irena A1 - Dhamo, Lorena T1 - Photoluminescence Properties of Different Types of Nanocrystals at the Ensemble and Single Emitter Level N2 - Correlating the photoluminescence (PL) properties of nanomaterials like semiconductor nanocrystals (QDs) and upconversion nanocrystals (UCNPs) assessed in ensemble studies and at the single particle level is increasingly relevant for applications of these nanomaterials in the life sciences like bioimaging studies or their use as reporters in microfluidic assays. Here we present a comparison of the spectroscopic properties of ensembles and single emitters for QDs like II/VI QDs and cadmium-free AIS/ZnS QDs as well as different UCNPs. The overall goal of this study was to derive particle architectures well suited for spectroscopic and microscopic applications. T2 - BIOSSPIE CY - San Francisco, CA, USA DA - 02.02.2019 KW - Quantum yield KW - Nanomaterial KW - Photoluminescence KW - Absolute fluorometry KW - Integrating sphere spectroscopy, KW - NIR KW - IR KW - Fluorescence KW - Nanoparticle KW - Semiconductor KW - Quantum dot KW - Single particle spectroscopy KW - Surface chemistry PY - 2019 AN - OPUS4-47358 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tietze, R. A1 - Panzer, R. A1 - Starzynski, T. A1 - Guhrenz, C. A1 - Frenzel, Florian A1 - Würth, Christian A1 - Resch-Genger, Ute A1 - Weigand, Jan J. A1 - Eychmüller, A. T1 - Synthesis of NIR-emitting InAs-based core/shell quantum dots with the use of tripyrazolylarsane as arsenic precursor JF - Particle & Particle Systems Characterization N2 - Tris(3,5-dimethylpyrazolyl)arsane (1) is introduced as a low-cost and convenient to handle arsenic precursor for the straight Forward synthesis of InAs Quantum dots (QDs). Transamination of 1 with the solvent oleylamine (OLAH) gives trioleylarsane (As(OLA)3) which in the presence of the reducing agents diisobutylaluminum hydride (DIBAL-H) or trioleylphosphane (P(OLA)3) yields InAs QDs via a typical hot injection approach. The size of the obtained InAs core QDs are tuned by varying the reaction time, the amount of the applied reducing agent, or even more effectively by changing the Indium and/or zinc halide precursors, InX3, and ZnX2 (Cl, Br, or I). Passivation of the resulting InAs particles with a protective ZnS or ZnSe shell results in improved photoluminescence of the core/shell QDs covering a spectral range between 600 and 1150 nm. KW - Quantum dot KW - NIR KW - Near infrared PY - 2018 DO - https://doi.org/10.1002/ppsc.201800175 SN - 0934-0866 SN - 1521-4117 VL - 35 IS - 9 SP - 1800175, 1 EP - 7 PB - Wiley AN - OPUS4-46076 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute A1 - Würth, Christian A1 - Kaiser, Martin T1 - Spectroscopic characterization of semiconductor and lanthanide-based nanocrystals with vis and NIR emission N2 - The increasing interest in molecular and nanoscale emitters with photoluminescence > 800 nm and recently also > 1000 nm for bioanalysis, medical diagnostics, bioimaging, and safety Barcodes requires quantitative spectroscopic studies, which are, however still challenging in this long wavelength region. This is of special relevance for nanocrystalline emitters like semiconductor quantum dots and rods as well as lanthanide-based upconversion and downconversion nanocrystals, where surface states and the accessibility of emissive states by quenchers largely control accomplishable photoluminescence quantum yields and hence, signal sizes and detection sensitivities from the reporter side. Moreover, nonlinear emitters like lanthanide-based upconversion nanocrystals require also power density-dependent studies of their luminescence spectra, quantum yields, and decay kinetics. Here, we present suitable absolute methods and underline the impact of such measurements on a profound mechanistic understanding of the nonradiative deactivation pathways in semiconductor and upconversion nanocrystals of different chemical composition and particle architecture. T2 - PCNSPA 2018 - Photonic Colloidal Nanostructures: Synthesis, Properties, and Applications CY - St. Petersburg, Russia DA - 04.06.2018 KW - Semiconductor KW - Nanoparticle KW - Quantum dot KW - Absolute fluorometry KW - Integrating sphere spectroscopy KW - NIR KW - IR KW - Fluorescence KW - Surface chemistry KW - Deactivation pathways KW - Photophysics KW - Modeling PY - 2018 AN - OPUS4-45796 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Geissler, Daniel A1 - Wegmann, Marc A1 - Hoffmann, Katrin A1 - Hannemann, M. A1 - Somma, V. A1 - Jochum, T. A1 - Niehaus, J. A1 - Roggenbuck, D. A1 - Resch-Genger, Ute T1 - NanoGenotox - Automatable Determination of the Genotoxicity of Nanoparticles with DNA-based Optical Assays N2 - Nanomaterials are used in many different applications in the material and life sciences. Examples are optical reporters, barcodes, and nanosensors, magnetic and optical contrast agents, and catalysts. Due to their small size and large surface area, there are also concerns about their interaction with and uptake by biological systems. This has initiated an ever increasing number of cyctoxicity studies of nanomaterials of different chemical composition and surface chemistry, but until now, the toxicological results presented by different research groups often do not address or differ regarding a potential genotoxicity of these nanomaterials. This underlines the need for a standardized test procedure to detect genotoxicity.1,2 Aiming at the development of fast, easy to use, and automatable microscopic methods for the determination of the genotoxicity of different types of nanoparticles, we assess the potential of the fluorometric γH2AX assay for this purpose. This assay, which can be run on an automated microscopic detection system, relies on the determination of DNA double strand breaks as a sign for genotoxicity.3 Here, we present first results obtained with broadly used nanomaterials like CdSe/CdS and InP/ZnS quantum dots as well as iron oxide, gold, and polymer particles of different surface chemistry with previously tested colloidal stability. These studies will be also used to establish nanomaterials as positive and negative genotoxicity controls or standards for assay performance validation for users of this fluorometric genotoxicity assay. In the future, after proper validation, this microscopic platform technology will be expanded to other typical toxicity assays. References. (1) Landsiedel, R.; Kapp, M. D.; Schulz, M.; Wiench, K.; Oesch, F., Reviews in Mutation Research 2009, 681, 241-258. (2) Henriksen-Lacey, M.; Carregal-Romero, S.; Liz-Marzán, L. M., Bioconjugate Chem. 2016, 28, 212-221. (3) Willitzki, A.; Lorenz, S.; Hiemann, R.; Guttek, K.; Goihl, A.; Hartig, R.; Conrad, K.; Feist, E.; Sack, U.; Schierack, P., Cytometry Part A 2013, 83, 1017-1026. T2 - 9th International Conference on Nanotoxicology - New tools in risk assessment of nanomaterials CY - Dusseldorf/Neuss, Germany DA - 18.09.2018 KW - Nano KW - Nanotoxicity KW - Fluorescence KW - Quantum dot KW - Surface KW - Passivation shell KW - Automated assay KW - Nanoparticle PY - 2018 AN - OPUS4-47540 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hübner, Oskar A1 - Resch-Genger, Ute A1 - Wegner, Karl David A1 - Hoffmann, Kristin T1 - Lifetime Barcoding of Polystyrene Beads with Fluorescent Nanocrystals for Fluorescent Lifetime Detection in Flow Cytometry N2 - Multiplexed encoding schemes of nano- and micrometer sized polymer particles with fluorescent dyes or quantum dots (QDs) and their optical detection, are of increasing interest for applications in the life sciences, for example in flow cytometry. Almost all strategies utilizing fluorescence focus on spectrally distinguishable emission bands or colors and different intensity levels as fluorescence codes. In this work the goal is to perform multiplexing with encoding fluorophores with different fluorescence lifetimes (LTs). In comparison to the spectral multiplexing strategies this has the advantage, that the different fluorescence LT codes can be measured with the same excitation and emission wavelength, thus reducing instrumental costs. Moreover, LTs should not depend on emitter concentration. Unlike organic dyes, the LTs of which are typically <10ns, the fluorescence LTs of ternary semiconductor QDs which represent a “green” alternative to conventional Cd-containing QDs are in the range of several hundred ns, independent of oxygen concentration, and can be tuned to a certain extent by chemical composition and surface chemistry. This presents a time region that can barely be covered by other emitters that have either much shorter or longer lifetimes. In this project, different encoding strategies will be assessed, and the encoded particles will then be used for fluorescence assays for the analysis of several targets in parallel. Therefore, the encoded particles will be functionalized with different target-specific bioligands and read out with a specifically designed flow cytometer enabling time-resolved fluorescence detection. With this instrument, the particles will be discriminated by their fluorescence LTs in one detection channel while the analytes will be quantified by fluorescence labels in a second channel in the intensity domain. T2 - Tag der Chemie 2019 CY - Berlin, Germany DA - 11.07.2019 KW - Multiplexing KW - Lifetime KW - Bead KW - Flow cytometry KW - Fluorescence KW - Quantum dot KW - InP KW - AIS KW - Dye KW - Encoding KW - Barcoding KW - Assay KW - Method PY - 2019 AN - OPUS4-49722 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -