TY - CONF A1 - Resch-Genger, Ute T1 - How to get it right with photoluminescence measurements in the UV/VIS/NIR N2 - Optical measurements of transparent solutions of organic dyes and semiconductor quantum dots and scattering materials such as luminescent nanocomposites and microparticles and phosphors dispersed in liquid and solid matrices play an important role in energy conversion, solid-state lighting, medical diagnostics, and security barcoding. A key performance parameter is the photoluminescence quantum yield QY, i.e., the number of emitted per number of absorbed photons. QY of transparent luminophore solutions can be obtained relative to a fluorescence QY standard of known QY. Such relative QY measurements require a calibrated spectrofluorometer. Here, we address typical sources of uncertainty for luminescence measurements and relative and absolute QY measurements from the instrument and material side and provide recommendations to circumvent or at least minimize them for transparent and scattering samples in the UV/vis/NIR/SWIR. T2 - Workshop "Photoluminescence Spectroscopy and its application in Materials Research" CY - Vienna, Austria DA - 19.02.2026 KW - Quality assurance KW - Reference material KW - Fluorescence KW - Dye KW - Traceability KW - Metrology KW - Calibration KW - Reference data KW - Reference product KW - Digital certificate KW - NIR KW - Instrument performance validation PY - 2026 AN - OPUS4-65575 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schlögl, Johanna A1 - Krappe, Alexander R. A1 - Fürstenwerth, Paul C. A1 - Brosius, Amelie L. A1 - Fasting, Carlo A1 - Hoffmann, Kurt F. A1 - Resch-Genger, Ute A1 - Eigler, Siegfried A1 - Steinhauer, Simon A1 - Riedel, Sebastian T1 - Luminescent Perhalofluoro Trityl Radicals N2 - In this proof-of-concept study, we show that polyfluorinated trityl radicals with the, to this date, highest fluorination grade can be accessed in quantitative yields in a straightforward manner starting from the perfluorinated trityl cation. The trityl skeleton is functionalized with trimethylsilyl halides to yield perhalofluoro trityl cations, which are subsequently reduced using commercial zinc powder. In this way, we prepare three perhalofluoro trityl radicals and analyze the impact of the fluorine ligands on their electro-optical properties, revealing some interesting trends. In comparison to literature-known polychlorinated trityl radicals, the new polyfluorinated derivatives exhibit substantially higher fluorescence quantum yields, longer luminescence lifetimes, and an expanded emission range that extends into the yellow spectral region. They further display enhanced photostability under light irradiation. In radical-stained polystyrene nanoparticles, an additional broad emission band in the red−NIR wavelength region is observed, which is attributed to excimer formation. Finally, the stability of the new radicals is investigated under ambient conditions, showing the slow conversion with atmospheric oxygen yielding the respective peroxides, which are characterized by single-crystal X-ray diffraction. All in all, our study extends the present scope of luminescent trityl radicals, as the functionalization of the perfluorinated cationic precursor unlocks the path toward a vast variety of polyfluorinated trityl radicals. KW - Dye KW - Fluorescence KW - Radical KW - Synthesis KW - Mechanism KW - Signal enhancement KW - Nano KW - Particle KW - Characterization KW - Quantum yield KW - Photophysics KW - Lifetime KW - Polarity KW - Polymer KW - Solvatchromism KW - Excimer PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-647973 DO - https://doi.org/10.1021/jacs.5c16418 SN - 0002-7863 VL - 147 IS - 46 SP - 1 EP - 8 PB - American Chemical Society (ACS) AN - OPUS4-64797 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Resch-Genger, Ute A1 - Abram, Sarah-Luise A1 - Tavernaro, Isabella A1 - Zou, Shan A1 - Johnston, Linda T1 - Behind the Paper: Nanoscale Reference and Test Materials for the Validation of Characterization Methods for Engineered Nanomaterials – Current State, Limitations and Needs N2 - Engineered nanomaterials (NMs) of different material composition, morphology, and surface chemistry are widely used in material and life sciences. For NM quality control and risk assessment, NM key properties must be characterized with validated methods, requiring reference materials (RMs). KW - Engineered Nanomaterials KW - Nanoscale reference materials KW - Interlaboratory comparisons KW - Traceability KW - Standardization and Regulation KW - Nano KW - Particle KW - Quality assurance KW - Surface chemistry PY - 2025 UR - https://communities.springernature.com/posts/nanoscale-reference-and-test-materials-for-the-validation-of-characterization-methods-for-engineered-nanomaterials-current-state-limitations-and-needs SP - 1 EP - 3 PB - Springer Nature CY - Online AN - OPUS4-62572 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Haroun, A. A. A. A1 - Derbala, H. A. A1 - Bassioni, G. A1 - Resch-Genger, Ute A1 - Shafik, E. S. A1 - Hassan, A. M. A. T1 - N-aminophthalimide as a novel UV-stabilizer to promote physico-mechanical properties of highdensity polyethylene (HDPE) N2 - This study aimed to evaluate the efficacy of Naminophthalimide (NAP) as a novel UV-stabilizer for highdensity polyethylene (HDPE) in improving its physicomechanical properties under UV exposure. NAP was synthesized by interaction between phthalimide and hydrazine hydrate. It was incorporated into HDPE with different weight ratios (1, 1.5, 2, and 3%), and its performancewas compared with Hostavin as a traditional UV stabilizer. The HDPE composites were exposed to UV irradiation for different periods (7 and 14 days) to evaluate their photodegradation behavior. Tensile strength, elongation at break were assessed before and after UV exposure. Also, oxidation induction time (OIT), melt flow rate (MFR), Vicat softening temperature were evaluated. Hostavin incorporation reduced tensile strength from 22.36 to 20.62MPa at higher concentrations. It has been found that 3% Hostavin, significantly improved elongation at break, increasing from 423% to 1,170%, suggesting enhanced flexibility. In contrast, NAP increased tensile strength to 22.9MPa and moderately enhanced elongation but slightly declined at 3%due to potential over-stabilization. Under UV exposure, retained tensile strength and elongation was improved with stabilizer content, which increasing tensile strength retention. The HDPE that containing NAP showed enhanced UV resistance and superior retention of mechanical properties compared to Hostavin. KW - Polymer KW - Advanced materials KW - Quality assurance KW - Stabilizer KW - Synthesis KW - Physico-mechanical properties PY - 2025 DO - https://doi.org/10.1515/polyeng-2024-0262 SN - 2191-0340 SP - 1 EP - 8 PB - De Gruyter CY - Berlin AN - OPUS4-63534 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute T1 - Reliable Photoluminescence Quantum Yields – New Reference Materials and Interlaboratory Comparisons N2 - The rational design and choice of molecular and nanoscale reporters, the comparison of different emitter classes, and photophysical and mechanistic studies require quantitative photoluminescence measurements and the reliable determination of the key performance parameter photoluminescence quantum yield (QY), i.e., the number of emitted per absorbed photons. This is of special importance for all photoluminescence applications in the life and material sciences in the UV/vis/NIR/SWIR. To improve the reliability and comparability of photoluminescence and QY measurements across laboratories, pitfalls, achievable uncertainties, and material-specific effects related to certain emitter classes must be explored. Also, suitable protocols and reference materials are needed which have been validated in interlaboratory comparisons for different wavelength regions and transparent and scattering luminophores.[1] Based on absolute and relative photoluminescence measurements of functional dyes and luminescent nanomaterials, reliable methods for determining QY of transparent and scattering luminophores, nonlinear emitters, and solid luminescent nanomaterials have been developed.[1-4] Thereby, material- and method-related uncertainties of relative and absolute QY measurements and achievable uncertainties could be quantified for linear and nonlinear UV/vis/NIR/SWIR emitters and lately for also luminescent and scattering materials and solid phoshors. In this context, we present the development and certification of a first set of UV/vis/NIR quantum yield standards with a complete uncertainty budget,[5] which present simple tools for a better comparability of QY measurements. In addition, a first interlaboratory comparison of absolute QY measurements of solid and scattering LED converter materials with integrating sphere spectroscopy has been performed.[5] The outcome of this study is presented, thereby addressing common pitfalls and measurement uncertainties and providing recommendations for the performance of reliable QY measurements of linear and non-linear emitters in transparent, scattering, and solid samples. T2 - Anakon 2025 CY - Leipzig, Germany DA - 10.03.2025 KW - Quality assurance KW - Reference material KW - Method KW - Fluorescence KW - Quantum yield KW - Absolute KW - Integrating sphere spectroscopy KW - Interlaboratory comparison KW - Dye KW - Film KW - Nano KW - Particle KW - Scattering KW - Uncertainty KW - LED converter PY - 2025 AN - OPUS4-62792 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Osiopova, Viktoriia A1 - Tavernaro, Isabella A1 - Ge, L. A1 - Kitzmann, W. R. A1 - Heinze, K. A1 - Reithofer, M. R. A1 - Resch-Genger, Ute T1 - Complete protection of NIR-luminescent molecular rubies from oxygen quenching in air by L-arginine-mediated silica nanoparticles N2 - The application of emerging luminophores such as near-infrared (NIR) emissive complexes based on earth-abundant chromium as central ion and triplet-triplet annihilation upconversion (TTA-UC) systems in air as optical reporters for bioimaging or photonic materials for energy conversion requires simple and efficient strategies for their complete protection from uminescence quenching by oxygen. Therefore, we explored the influence of sol–gel synthesis routes on the oxygen protection efficiency of the resulting core and core/shell silica nanoparticles (SiO2 NPs), utilizing the molecular ruby-type luminophores CrPF6 ([Cr(ddpd)2](PF6)3; ddpd = N,N'-dimethyl-N,N'-dipyridin-2-ylpyridin-2,6-diamine) and CrBF4 ([Cr(ddpd)2](BF4)3) with their oxygendependent, but polarity-, proticity-, viscosity-, and concentration-independent luminescence as optical probes for oxygen permeability. The sol–gel chemistry routes we assessed include the classical Stöber method and the underexplored Larginine approach, which relies on the controlled hydrolysis of tetraethoxysilane (TEOS) in a biphasic cyclohexane/water system with the catalyst L-arginine. As demonstrated by luminescence measurements of air- and argon-saturated dispersions of CrPF6- and CrBF4-stained SiO2 NPs of different size and particle architecture, utilizing the luminescence decay kinetics of argon-saturated solutions of CrPF6 and CrBF4 in acetonitrile (ACN) as benchmarks, only SiO2 NPs or shells synthesized by the L-arginine approach provided complete oxygen protection of the CrIII complexes under ambient conditions. We ascribe the different oxygen shielding efficiencies of the silica networks explored to differences in density and surface chemistry of the resulting nanomaterials and coatings, leading to different oxygen permeabilities. Our Larginine based silica encapsulation strategy can open the door for the efficient usage of oxygen-sensitive luminophores and TTA-UC systems as optical reporters and spectral shifters in air in the future. KW - Quality assurance KW - Fluorescence KW - Quantification KW - Advanced materials KW - Nano KW - Quantum yield KW - NIR KW - Characterization KW - Electron microscopy KW - Silica KW - Synthesis KW - Oxygen sensing KW - Surface KW - Doping KW - Lifetime KW - Cr(III) complex KW - Shielding KW - Sensing PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-638271 DO - https://doi.org/10.26599/NR.2025.94907241 SN - 1998-0000 VL - 18 IS - 3 SP - 1 EP - 13 PB - SciOpen AN - OPUS4-63827 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute A1 - Fallisch, A. A1 - Petrov, E. P. A1 - Salhany, R. A1 - Forthman, C. A1 - Guttenberg, Z. A1 - Nitschke, R. T1 - Spectral fluorescence standards for the calibration and performance validation of fluorescence microscopes N2 - The standardization and calibration of fluorescence microscopy have become increasingly vital due to the wide-spread use of in life and materials sciences. As the demand for reliable and user-friendly methods to assess micro-scope performance grows, universal calibration tools accessible to both researchers and vendors are needed. To support the standardization of characterization methods in microscopy, it is crucial to provide calibration tools together with standardized operating procedures for their effective implementation. The public-funded project "FluMiKal"* develops calibration tools in the shape of typical microscopic slides to assess key parameters such as spatial resolution, point spread function, spectral sensitivity, linearity and sensitivity of the detection system. The focus is on creating calibration tools that are user-friendly, robust, and versatile in their application. This work addresses the critical parameter of wavelength-dependent spectral sensitivity, which affects the meas-ured signals from the instrument side, yielding instrument-specific data and instrument aging-induced changes over time. For this purpose, μ-slides from ibidi with six channels are used, allowing them to be filled with different solutions containing molecular or nanoscale fluorophores with well-characterized absorption and fluorescence properties. The certified spectral fluorescence standards BAM-F003, F004, F005, and F007 assessed provided as ethanolic solutions by the Federal Institute for Materials Research and Testing (BAM), cover a broad spectral range from the blue to the near-infrared [1], [2]. Dye-based slide prototypes have been used to determine the spectral sensitivity of confocal microscopes from different vendors with various detector types by acquiring the spectral data of the BAM dyes under standardized measurement conditions, demonstrating the applicability of this concept. Proof-of-concept experiments could demonstrate the proper sealing of the slides. Further experiments will explore long-term stability and their potential as standards for relative intensity calibrations. * FluMiKal is funded by the Federal Ministry for Economic Affairs and Climate Action, Germany (WIPANO FKZ 03TN0047B) [1] doi: 10.1007/4243_2008_028. [2] doi: 10.1007/s00216-024-05723-w. T2 - European Light Microscopy Initiative - ELMI 2025 CY - Heidelberg, Germany DA - 03.06.2025 KW - Fluorescence KW - Advanced material KW - Validation KW - Calibration KW - Method comparison KW - Reference material KW - Dye KW - Fluorescence standard KW - Microscopy KW - CLSM KW - Imaging PY - 2025 AN - OPUS4-64206 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Resch-Genger, Ute T1 - Reliable measurements of the photoluminescence quantum yield of transparent and scattering luminophores N2 - Optical measurements of transparent solutions of organic dyes and semiconductor quantum dots and scattering materials such as luminescent nanocomposites and microparticles and phosphors dispersed in liquid and solid matrices play an important role in energy conversion, solid-state lighting, medical diagnostics, and security barcoding. A key performance parameter is the photoluminescence quantum yield QY, i.e., the number of emitted per number of absorbed photons. QY of transparent luminophore solutions can be obtained relative to a fluorescence QY standard of known QY.[1] Meanwhile, a first set of certified fluorescence QY standards is available.[2] Such relative QY measurements require a calibrated spectrofluorometer.[1,3] For determining QY of scattering liquid and solid samples, absolute measurements of QY with a calibrated integrating sphere setup are mandatory.[1,4,5] However, scattering QY standards are not available and uncertainties of such measurements have not yet been assessed in interlaboratory comparisons (ILCs). To determine typical sources of uncertainty of absolute QY measurements, we assessed the influence of the measurement geometry and the optical properties of the blank for determining the number of incident photons absorbed by the sample in an ILC using commercial integrating sphere setups and a custom-designed integrating sphere setup. Samples examined included transparent and scattering dye solutions, solid phosphors such as YAG:Ce optoceramics used as LED converter material, and polymer films stained with different amounts of phosphor microparticles. Matching QY values could be obtained for transparent dye solutions and scattering dispersions with a blank with scattering properties closely matching those of the sample, while QY measurements of optoceramic samples with different blanks revealed substantial differences of more than 20 %. Based on our data, we recommend non-absorbing blank materials with a high reflectivity (>95 %) such as a 2 mm-thick PTFE target placed on the sample holder as blanks. T2 - eMRS 2025 Fall Meeting CY - Warsaw, Poland DA - 15.09.2025 KW - Quality assurance KW - Fluorescence KW - Nano KW - Particle KW - Advanced material KW - Synthesis KW - Characterization KW - Fluorescence quantum yield KW - Phosphor KW - Absolute KW - Integrating sphere spectroscopy KW - Dye KW - Standardization KW - Reference material KW - Interlaboratory comparison KW - Uncertainty PY - 2025 AN - OPUS4-64184 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Soyka, J. P. A1 - Witte, J. F. A1 - Wiesner, A. A1 - Krappe, A. R. A1 - Wehner, D. A1 - Alnicola, N. A1 - Paulus, B. A1 - Resch-Genger, Ute A1 - Eigler, S. T1 - [3]Radialene Fluorophores with pH-Switchable Emission and Stable Absorption Maxima N2 - The first push–pull quino [3]radialene fluorescent dye is reported. Herein, the novel bis(dicyanomethylene)-[3]radialene electron acceptor is connected to a benzimidazole donor. With protonation, a substantial redshift of fluorescence wavelength is observed, while the absorption maximum remains stable. This process is accompanied with an increased fluorescence quantum yield to about 70%. Further, the findings are explained by a combined experimental and theoretical approach, and it is found that vibronic coupling plays a crucial role. This study highlights the yet unexplored potential of [3]radialene-based motifs for the design of environment-responsive fluorophores. KW - DADQ KW - Nanographene KW - fluorescence KW - Nano KW - Particle KW - Synthesis KW - Characterization KW - Advanced material KW - Quantum yield KW - Photophysic KW - pH KW - Probe KW - Sensor KW - Lifetime KW - Polarity PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-642147 DO - https://doi.org/10.1002/ejoc.202500669 SN - 1099-0690 SP - 1 EP - 6 PB - Wiley-VCH CY - Weinheim AN - OPUS4-64214 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hartmann, Yannic A1 - El Abbassi, Abdelouahad A1 - Mayer, Bernhard A1 - Resch-Genger, Ute A1 - Müller, Thomas J. J. T1 - Ester‐Aroyl‐S,N‐Ketene Acetals with Solid‐State Luminescence: AIEgens from Sequential Three‐Component Desymmetrization N2 - AbstractDi(hetero)aroyl dichlorides are desymmetrized upon sequential reaction with alcohols and 2‐methyl N‐benzyl thiazolium salts within the course of a one‐pot three‐component reaction yielding ester‐substituted aroyl‐S,N‐ketene acetals under mild conditions in good yields. A prerequisite for the concise one‐pot process is the different nucleophilicity of the alcohols and in situ generated S,N‐ketene acetals. The resulting compounds are merocyanines with dominant charge‐transfer absorption bands which are fluorescent in the solid state, but not in solution. In water/ethanol solvent mixtures of increasing water content, the water‐insoluble dyes display typical aggregation‐induced emission (AIE) characteristics. The water fraction inducing AIE as well as the emission color, and fluorescence quantum yield (Φf) of the aggregated dyes can be controlled by the alcohol part of the ester moiety. Encapsulation into polystyrene nanoparticles can lead to a considerable increase of the fluorescence quantum yield Φf to 30% as shown for a representatively chosen dye revealing the highest Φf of 11% within the dye series in the water/ethanol mixtures and enabling the usage of these dyes as fluorescent reporters in aqueous environments. KW - Dye KW - Fluorescence KW - Aggregation KW - Mechanism KW - Signal enhancement KW - Nano KW - Particle KW - Characterization KW - Quantum yield KW - Photophysics KW - Probe KW - Sensor KW - Lifetime KW - Polarity PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-642400 DO - https://doi.org/10.1002/chem.202502071 SN - 0947-6539 SP - 1 EP - 10 PB - Wiley-VCH CY - Weinheim AN - OPUS4-64240 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -