TY - JOUR A1 - Resch-Genger, Ute A1 - Hoffmann, Katrin A1 - Würth, Christian A1 - Behnke, Thomas A1 - Hoffmann, Angelika A1 - Pfeifer, Dietmar A1 - Engel, A. T1 - The toolbox of fluorescence standards: Flexible calibration tools for the standardization of fluorescence-based measurements N2 - To improve the reliability of fluorescence data in the life and material sciences and to enable accreditation of fluorescence techniques, standardization concepts are required that guarantee and improve the comparability of fluorescence measurements. At the core of such concepts are simple and evaluated fluorescence standards for the consideration of instrument-specific spectral and intensity distortions of measured signals and for instrument performance validation (IPV). Similarly in need are fluorescence intensity standards for the quantification from measured intensities and for signal referencing, thereby accounting for excitation light-induced intensity fluctuations. These standards should be preferably certified, especially for use in regulated areas like medical diagnostics. This encouraged us to develop liquid and solid standards for different fluorescence parameters and techniques for use under routine measurement conditions in different formates. Special emphasis was dedicated to the determination and control of the spectral responsivity of detection systems, wavelength accuracy, homogeneity of illumination, and intensity referencing for e.g. spectrofluorometers, fluorescence sensors and confocal laser scanning fluorescence microscopes. Here, we will present design concepts and examples for mono- and multifunctional fluorescence standards that provide traceability to radiometric units and present a first step towards a toolbox of standards. KW - Fluorescence KW - Fluorescence standard KW - Calibration tool KW - Spectral fluorescence standard KW - Intensity standard KW - Instrument performance validation KW - Quality assurance KW - Traceability KW - Glass KW - Liquid standard PY - 2010 DO - https://doi.org/10.1117/12.853133 SN - 0277-786X SN - 0038-7355 SN - 0361-0748 VL - 7666 IS - 76661J SP - 1 EP - 12 PB - Soc. CY - Redondo Beach, Calif. [u.a.] AN - OPUS4-21595 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Kazlagic, Anera A1 - Rosner, M. A1 - Cipriani, A. A1 - Frick, D. A. A1 - Glodny, J. A1 - Hoffmann, E. J. A1 - Hora, J. M. A1 - Irrgeher, J. A1 - Lugli, F. A1 - Magna, T. A1 - Meisel, T. C. A1 - Meixner, A. A1 - Possolo, A. A1 - Pramann, A. A1 - Pribil, M. J. A1 - Prohaska, T. A1 - Retzmann, A. A1 - Rienitz, O. A1 - Rutherford, D. A1 - Paula-Santos, G. M. A1 - Tatzel, M. A1 - Widhalm, S. A1 - Willbold, M. A1 - Zuliani, T. A1 - Vogl, Jochen T1 - Data of the characterisation of conventional 87Sr/86Sr isotope ratios in cement, limestone and slate reference materials based on an interlaboratory comparison study N2 - This dataset represents the electronic supplementary material (ESM) of the publication entitled "Characterisation of conventional 87Sr/86Sr isotope ratios in cement, limestone and slate reference materials based on an interlaboratory comparison study", which is published in Geostandards and Geoanalytical Research under the DOI: 10.1111/GGR.12517. It consists of four files. 'ESM_Data.xlsx' contains all reported data of the participants, a description of the applied analytical procedures, basic calculations, the consensus values, and part of the uncertainty assessment. 'ESM_Figure-S1' displays a schematic on how measurements, sequences and replicates are treated for the uncertainty calculation carried out by PTB. 'ESM_Technical-protocol.pdf' is the technical protocol of the interlaboratory comparison, which has been provided to all participants together with the samples and which contains bedside others the definition of the measurand and guidelines for data assessment and calculations. 'ESM_Reporting-template.xlsx' is the Excel template which has been submitted to all participants for reporting their results within the interlaboratory comparison. Excel files with names of the the structure 'GeoReM_Material_Sr8786_Date.xlsx' represent the Rcon(87Sr/86Sr) data for a specific reference material downloaded from GeoReM at the specified date, e.g. 'GeoReM_IAPSO_Sr8786_20221115.xlsx' contains all Rcon(87Sr/86Sr) data for the IAPSO seawater standard listed in GeoReM until 15 November 2022. KW - Reference data KW - Strontium isotope ratio KW - Interlaboratory comparison KW - Reference material KW - Cement KW - Geological material KW - Value assignment KW - Measurement uncertainty KW - Conventional method PY - 2023 UR - https://doi.org/10.5281/zenodo.7804445 DO - https://doi.org/10.5281/zenodo.7804444 PB - Zenodo CY - Geneva AN - OPUS4-57809 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Abou-Ras, D. A1 - Caballero, R. A1 - Fischer, C.-H. A1 - Kaufmann, C.A. A1 - Lauermann, I. A1 - Mainz, R. A1 - Mönig, H. A1 - Schöpke, A. A1 - Stephan, C. A1 - Streeck, C. A1 - Schorr, S. A1 - Eicke, A. A1 - Döbeli, M. A1 - Gade, B. A1 - Hinrichs, J. A1 - Nunney, T. A1 - Dijkstra, H. A1 - Hoffmann, V. A1 - Klemm, D. A1 - Efimova, V. A1 - Bergmaier, A. A1 - Dollinger, G. A1 - Wirth, Thomas A1 - Unger, Wolfgang A1 - Rockett, A.A. A1 - Perez-Rodriguez, A. A1 - Alvarez-Garcia, J. A1 - Izquierdo-Roca, V. A1 - Schmid, T. A1 - Choi, P.-P. A1 - Müller, M. A1 - Bertram, F. A1 - Christen, J. A1 - Khatri, H. A1 - Collins, R.W. A1 - Marsillac, S. A1 - Kötschau, I. T1 - Comprehensive comparison of various techniques for the analysis of elemental distributions in thin films N2 - The present work shows results on elemental distribution analyses in Cu(In,Ga)Se2 thin films for solar cells performed by use of wavelength-dispersive and energy-dispersive X-ray spectrometry (EDX) in a scanning electron microscope, EDX in a transmission electron microscope, X-ray photoelectron, angle-dependent soft X-ray emission, secondary ion-mass (SIMS), time-of-flight SIMS, sputtered neutral mass, glow-discharge optical emission and glow-discharge mass, Auger electron, and Rutherford backscattering spectrometry, by use of scanning Auger electron microscopy, Raman depth profiling, and Raman mapping, as well as by use of elastic recoil detection analysis, grazing-incidence X-ray and electron backscatter diffraction, and grazing-incidence X-ray fluorescence analysis. The Cu(In,Ga)Se2 thin films used for the present comparison were produced during the same identical deposition run and exhibit thicknesses of about 2 µm. The analysis techniques were compared with respect to their spatial and depth resolutions, measuring speeds, availabilities, and detection limits. KW - Elemental distributions KW - Comparison KW - Depth profiling KW - Chemical mapping KW - Thin films KW - Solar cells KW - Chalcopyrite-type KW - Cu(In,Ga)Se2 PY - 2011 DO - https://doi.org/10.1017/S1431927611000523 SN - 1431-9276 SN - 1435-8115 VL - 17 IS - 5 SP - 728 EP - 751 PB - Cambridge University Press CY - New York, NY AN - OPUS4-24506 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kazlagić, Anera A1 - Rosner, M. A1 - Cipriani, A. A1 - Frick, D. A. A1 - Glodny, J. A1 - Hoffmann, E. J. A1 - Hora, J. M. A1 - Irrgeher, J. A1 - Lugli, F. A1 - Magna, T. A1 - Meisel, T. C. A1 - Meixner, A. A1 - Possolo, A. A1 - Pramann, A. A1 - Pribil, M. J. A1 - Prohaska, T. A1 - Retzmann, Anika A1 - Rienitz, O. A1 - Rutherford, D. A1 - Paula-Santos, G. M. A1 - Tatzel, M. A1 - Widhalm, S. A1 - Willbold, M. A1 - Zuliani, T. A1 - Vogl, Jochen T1 - Characterisation of conventional 87Sr/86Sr isotope ratios in cement, limestone and slate reference materials based on an interlaboratory comparison study N2 - An interlaboratory comparison (ILC)was organised to characterise 87Sr/86Sr isotope ratios in geological and industrial reference materials by applying the so-called conventional method for determining 87Sr/86Sr isotope ratios. Four cements (VDZ 100a,VDZ 200a, VDZ 300a, IAG OPC-1), one limestone (IAG CGL ML-3) and one slate (IAG OU-6) reference materials were selected, covering a wide range of naturally occurring Sr isotopic signatures. Thirteen laboratories received aliquots of these six reference materials together with a detailed technical protocol. The consensus values for the six reference materials and their associated measurement uncertainties were obtained by applying a Gaussian, linear mixed effects model fitted to all the measurement results. By combining the consensus values and their uncertainties with an uncertainty contribution for potential heterogeneity, reference values ranging from 0.708134 mol mol-1 to 0.729778 mol mol-1 were obtained with relative expanded uncertainties of ≤ 0.007 %. This study represents an ILC on conventional 87Sr/86Sr isotope ratios, within which metrological principles were considered and the compatibility of measurement results obtained by MC-ICP-MS and by MC-TIMS is demonstrated. The materials characterised in this study can be used as reference materials for validation and quality control purposes and to estimate measurement uncertainties in conventional 87Sr/86Sr isotope ratio measurement. KW - Sr isotope analysis KW - Isotope ratios KW - Cement KW - Geological material KW - MC-TIMS KW - MC-ICP-MS KW - Interlaboratory comparison KW - Measurement uncertainty KW - Cconventional method PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-579836 DO - https://doi.org/10.1111/ggr.12517 SN - 1639-4488 VL - 47 IS - 4 SP - 821 EP - 840 PB - Wiley online library AN - OPUS4-57983 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Noble, J.E. A1 - Wang, L. A1 - Cerasoli, E. A1 - Knight, A.E. A1 - Porter, R.A. A1 - Gray, E. A1 - Howe, C. A1 - Hannes, E. A1 - Corbisier, P. A1 - Wang, J. A1 - Wu, L. A1 - Altieri, I. A1 - Patriarca, M. A1 - Hoffmann, Angelika A1 - Resch-Genger, Ute A1 - Ebert, B. A1 - Voigt, Jan A1 - Shigeri, Y. A1 - Vonsky, M.S. A1 - Konopelko, L.A. A1 - Gaigalas, A.K. A1 - Bailey, M. J. A. T1 - An international comparability study to determine the sources of uncertainty associated with a non-competitive sandwich fluorescent ELISA KW - ELISA KW - Fluorescence KW - Interferon KW - Uncertainty KW - Round Robin KW - Immunoassay KW - Quality assurance KW - Fluorescein PY - 2008 SN - 1434-6621 SN - 1437-8523 VL - 46 IS - 7 SP - 1033 EP - 1045 PB - De Gruyter CY - Berlin AN - OPUS4-18283 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Angeli, J. A1 - Bengtson, A. A1 - Bogaerts, A. A1 - Hoffmann, V. A1 - Hodoroaba, Vasile-Dan A1 - Steers, E. T1 - Glow discharge optical emission spectrometry: moving towards reliable tion film analysis - a short review N2 - Glow discharge optical emission spectroscopy (GD-OES) is briefly reviewed, with particular reference to topics relevant to the application field of near surface and thin film analysis. The special needs and requirements for thin film analysis, in contrast to coating and bulk analysis, are pointed out. A task list is developed which shows the requirements of further developments to the technique and the fundamentals. The state-of-the-art is presented in measurement technique, GD source control and design, the effect of traces of molecular gases, correction and quantification procedures, contributions of modelling and, finally, reference materials for thin film analysis. PY - 2003 DO - https://doi.org/10.1039/b301293j SN - 0267-9477 SN - 1364-5544 VL - 18 IS - 6 SP - 670 EP - 679 PB - Royal Society of Chemistry CY - London AN - OPUS4-2533 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lisec, Jan A1 - Hoffmann, F. A1 - Jaeger, C. A1 - Bhattacharya, A. A1 - Schmitt, C. A. T1 - Nontargeted Identification of Tracer Incorporation in High- Resolution Mass Spectrometry N2 - “Fluxomics” refers to the systematic analysis of metabolic fluxes in a biological system and may uncover novel dynamic properties of metabolism that remain undetected in conventional metabolomic approaches. In labeling experiments, tracer molecules are used to track changes in the isotopologue distribution of metabolites, which allows one to estimate fluxes in the metabolic network. Because unidentified compounds cannot be mapped on pathways, they are often neglected in labeling experiments. However, using recent developments in de novo annotation may allow to harvest the information present in these compounds if they can be identified. Here, we present a novel tool (HiResTEC) to detect tracer incorporation in high-resolution mass spectrometry data sets. The software automatically extracts a comprehensive, nonredundant list of all compounds showing more than 1% tracer incorporation in a nontargeted fashion. We explain and show in an example data set how mass precision and other filter heuristics, calculated on the raw data, can efficiently be used to reduce redundancy and noninformative signals by 95%. Ultimately, this allows to quickly investigate any labeling experiment for a complete set of labeled compounds (here 149) with acceptable false positive rates. We further re-evaluate a published data set from liquid chromatography-electrospray ionization (LC-ESI) to demonstrate broad applicability of our tool and emphasize importance of quality control (QC) tests. HiResTEC is provided as a package in the open source software framework R and is freely available on CRAN. KW - Fluxomics KW - R package KW - Mass-Spectrometry PY - 2018 DO - https://doi.org/10.1021/acs.analchem.8b00356 VL - 90 IS - 12 SP - 7253 EP - 7260 PB - ACS Publications AN - OPUS4-45493 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rietsch, P. A1 - Sobottka, S. A1 - Hoffmann, K. A1 - Popov, A. A. A1 - Hildebrandt, P. A1 - Sarkar, B. A1 - Resch-Genger, Ute A1 - Eigler, S. T1 - Between Aromatic and Quinoid Structure: A Symmetrical UV to Vis/NIR Benzothiadiazole Redox Switch N2 - Reversibly switching the light absorption of organic molecules by redox processes is of interest for applications in sensors, light harvesting, smart materials, and medical diagnostics. This work presents a symmetrical benzothiadiazole (BTD) derivative with a high fluorescence quantum yield in solution and in the crystalline state and shows by spectroelectrochemical analysis that reversible switching of UV absorption in the neutral state, to broadband Vis/NIR absorption in the 1st oxidized state, to sharp band Vis absorption in the 2nd oxidized state, is possible. For the one-electron oxidized species, formation of a delocalized radical is confirmed by electron paramagnetic resonance spectroelectrochemistry. Furthermore, our results reveal an increasing quinoidal distortion upon the 1st and 2nd oxidation, which can be used as the leitmotif for the development of BTD based redox switches. KW - Dye KW - Electrochemistry KW - Switch KW - Redox KW - Sensor KW - Photophysics KW - Quantum yield KW - photoluminescence PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-517222 DO - https://doi.org/10.1002/chem.202004009 VL - 26 IS - 72 SP - 17361 EP - 17365 PB - Wiley-VCH GmbH AN - OPUS4-51722 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wagner, M. R. A1 - Schlichting, S. A1 - Müßener, J. A1 - Hille, P. A1 - Teubert, J. A1 - Schörmann, J. A1 - Rosenauer, A. A1 - Eickhoff, M. A1 - Hoffmann, A. A1 - Callsen, G. A1 - Hönig, Gerald T1 - Suppression of the quantum confined Stark effect in polar III-nitride heterostructures N2 - One of the most significant limitations for the quantum efficiency of group III-nitride based light emitters is the spatial electron-hole separation due to the quantum-confined Stark effect (QCSE). To overcome this problem, Hönig et al. [1] proposed a novel concept, the Internal-Field-Guarded-Active-Region Design (IFGARD), which suppresses the QCSE for wurtzite crystals in the [0001] direction. Here, we show how encapsulating the active region by additional guard layers results in a strong reduction of the built-in electric field in c-plane wurtzite nanostructures. Even more importantly, we demonstrate the first experimental evidence for the successful realization of an IFGARD structure based on GaN/AlN heterostructures embedded in GaN nanowires. By means of power-dependent and time-resolved µ-photoluminescence (µ-PL) we experimentally proof the validity of the unconventional IFGARD structure. We managed to tune the emission of 4-nm-thick GaN nano-discs up to 3.32 eV at low excitation powers, which is just 150 meV below the bulk GaN bandgap. Our results demonstrate an almost complete elimination of the QCSE in comparison to conventional structures which show approximately 1 eV red-shifted emission. The suppression of the QCSE results in a significant increase of the radiative exciton decay rates by orders of magnitude and demonstrates the potential of IFGARD structures for future light sources based on polar heterostructures. [1] Hönig et al., Phys. Rev. Applied 7, 024004 (2017) T2 - International Conference on Nitride Semiconductors 12 of the European Materials Research Society CY - Strasbourg, France DA - 24.07.2017 KW - Nanophotonics KW - Piezoelectricity KW - Quantum confined stark effect KW - Semiconductor nanostructures KW - Spontaneous polarization PY - 2017 AN - OPUS4-41194 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schlichting, S. A1 - Hönig, Gerald A1 - Müßener, J. A1 - Hille, P. A1 - Grieb, T. A1 - Westerkamp, S. A1 - Teubert, J. A1 - Schörmann, J. A1 - Wagner, M.R. A1 - Rosenauer, A. A1 - Eickhoff, M. A1 - Hoffmann, A. A1 - Callsen, G. T1 - Suppression of the quantum-confined Stark effect in polar nitride heterostructures N2 - Recently, we suggested an unconventional approach (the so-called Internal-Field-Guarded-Active-Region Design “IFGARD”) for the elimination of the quantum-confined Stark effect in polar semiconductor heterostructures. The IFGARD-based suppression of the Stark redshift on the order of electronvolt and spatial charge carrier separation is independent of the specific polar semiconductor material or the related growth procedures. In this work, we demonstrate by means of micro-photoluminescence techniques the successful tuning as well as the elimination of the quantum-confined Stark effect in strongly polar [000-1] wurtzite GaN/AlN nanodiscs as evidenced by a reduction of the exciton lifetimes by up to four orders of magnitude. Furthermore, the tapered geometry of the utilized nanowires (which embed the investigated IFGARD nanodiscs) facilitates the experimental differentiation between quantum confinement and Stark emission energy shifts. Due to the IFGARD, both effects become independently adaptable. KW - Nanophotonics KW - Photonic devices KW - Single photon and quantum effects PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-457884 DO - https://doi.org/10.1038/s42005-018-0044-1 SN - 2399-3650 VL - 1 SP - 1 EP - 8 PB - Springer Nature CY - London AN - OPUS4-45788 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -