TY - JOUR A1 - Miropoltsev, M. A1 - Wegner, Karl David A1 - Häusler, I. A1 - Hodoroaba, Vasile-Dan A1 - Resch-Genger, Ute T1 - Influence of Hydrophilic Thiol Ligands of Varying Denticity on the Luminescence Properties and Colloidal Stability of Quaternary Semiconductor Nanocrystals N2 - Binary photoluminescent semiconductor nanocrystals (quantum dots, QDs) are one of the best studied fluorescent nanomaterials, and their unique optoelectronic properties paved the road to many applications in (bio)nanophotonics, optoelectronics, and photovoltaics. However, concerns related to their toxic constituents like cadmium or lead and the emerging interest in greener chemistry synthesis approaches hamper their future applicability. Interesting alternatives for some applications like biosensing or bioimaging are heavy-metal-free ternary QDs like AgInS2 (AIS), CuInS2 (CIS), and quaternary QDs such as AIS-ZnS (ZAIS). In this context, we explored the effect of ligand denticity on the organic-to-aqueous phase transfer of oleylamine-stabilized ZAIS QDs with the hydrophilic ligands mercaptopropionic acid (MPA), dihydrolipoic acid (DHLA), and 3-mercapto-2,2-bis(mercaptomethyl)propanoic acid (3MPA), bearing mono-, bi-, and trialkyl thiol groups. Spectroscopic studies of the resulting water-dispersible ZAIS QDs revealed a considerable influence of ligand denticity and ligand-to-QD ratio on the spectral position and width (FWHM; full width at half-maximum) of the photoluminescence (PL) bands, the PL quantum yields (PL QY), and the PL decay kinetics. Thiol capping and phase transfer resulted in a loss in PL by at least a factor of 2. The ligand-induced PL quenching observed particularly for ligands bearing two or three thiol groups was attributed to the facilitated formation of surface-bound disulfides. The best colloidal stability under high dilution conditions was observed for 3MPA. KW - Quantum dots KW - Ligand exchange KW - Lifetime analysis KW - Thiols PY - 2022 DO - https://doi.org/10.1021/acs.jpcc.2c05342 SN - 1932-7447 VL - 126 IS - 47 SP - 20101 EP - 20113 PB - ACS Publications AN - OPUS4-56707 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Le Guevel, X. A1 - Wegner, Karl David A1 - Würth, Christian A1 - Baulin, V. A. A1 - Musnier, B. A1 - Josserand, V. A1 - Resch-Genger, Ute A1 - Koll, J-C T1 - Tailoring the SWIR emission of gold nanoclusters by surface ligand rigidification and their application in 3D bioimaging N2 - The influence of solvent polarity and surface ligand rigidification on the SWIR emission profile of gold nanoclusters with an anistropic surface was investigated. A strong enhancement of the SWIR emission band at 1200 nm was observed when measuring in different local environments: in solution, in polymer composites, and in solids. SWIR in vivo imaging of mice assisted by deep learning after intravenous administration of these gold nanoclusters provides high definition pseudo-3D views of vascular blood vessels. KW - Nano KW - Nanomaterial KW - Metal cluster KW - Photoluminescence KW - Quantum yield KW - Photophysics KW - Lifetime KW - Sensor KW - NIR KW - SWIR KW - Ligand KW - Gold KW - Mechanism KW - Charge transfer KW - Enhancement strategy KW - Imaging KW - Application KW - Contrast agent PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543582 DO - https://doi.org/10.1039/D1CC06737K VL - 58 IS - 18 SP - 2967 EP - 2970 PB - RSC AN - OPUS4-54358 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wegner, Karl David A1 - Reiss, P. A1 - Carriere, M. A1 - Pouget, S. A1 - Resch-Genger, Ute T1 - Luminescent Quantum dots – the next-generation nano light bulbs N2 - Fluorescent semiconductor nanocrystals, also known as quantum dots (QDs), enabled many advancements in biotechnology, photovoltaics, photocatalysis, quantum computing and display devices. The high versatility of this nanomaterial is based on their unique size-tunable photoluminescence properties, which can be adjusted from the visible to the near-infrared range. In contrast to other nanomaterials, QDs made the transition from a laboratory curiosity to the utilization in commercial products, like the QLED television screen or in smartphone displays. The best investigated QDs are composed of heavy metals like cadmium or lead, which is not the best choice in terms of toxicity and environmental pollution. A more promising material is Indium Phosphide (InP), which is also currently used by Samsung, Sony and co. in the QLED displays. In this contribution, I would like to give you a sneak peek behind the curtains of nanomaterial synthesis and show how this material is produced, how to stabilize their structural properties, and assess their toxicity in environmentally relevant conditions. Furthermore, I would like to present a synthesis method to accomplish the last open challenge in display technology of a blue luminescent LED based on QDs by introducing a new element to the InP QDs. T2 - The Berlin Postdoc Day CY - Berlin, Germany DA - 03.11.2022 KW - InP KW - Quantum dots KW - Fluorescence KW - Aging KW - Doping KW - Nanomaterial KW - Cytotoxicity PY - 2022 AN - OPUS4-56194 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Koch, Claudia A1 - Ladu, Luana A1 - Asna Ashari, Parsa A1 - Blind, K. A1 - Castka, P. T1 - Digitalization in conformity assessment in Germany - A QI-FoKuS study T1 - Digitalisierung in der Konformitätsbewertung in Deutschland - Eine QI-FoKuS-Studie N2 - This report summarizes findings from the first comprehensive study on digitalization in conformity assessment in Germany. The reults are based on data from a survey among conformity assessment bodies (CABs) conducted in 2022. It highlights the digital maturity of the organizations, the motives, benefits and obstacles of digital transformation as well as the actual technology trends. The study on German CABs is part of a global project that covers various other countries (see www.qi-fokus.de). N2 - Dieser Bericht fasst die Ergebnisse der ersten umfassenden Studie zur Digitalisierung der Konformitätsbewertung in Deutschland zusammen. Die Ergebnisse basieren auf Daten einer Umfrage unter Konformitätsbewertungsstellen (KBS), die 2022 durchgeführt wurde. Sie beleuchten den digitalen Reifegrad der Organisationen, die Motive, Vorteile und Hindernisse der digitalen Transformation sowie die aktuellen Technologietrends. Die Studie zu KBS in Deutschland ist Teil eines globalen Projekts, das verschiedene andere Länder umfasst (siehe www.qi-fokus.de). KW - Quality infrastructure KW - Digitalization KW - Testing KW - Conformity assessment KW - Certification KW - Laboratory KW - Digital transformation KW - TIC KW - Conformity assessment body KW - COVID-19 KW - Calibration KW - Corona KW - Digitalisierung KW - Kalibrierung KW - Konformitätsbewertung KW - Konformitätsbewertungsstelle KW - Labor KW - Prüfung KW - Qualitätsinfrastruktur KW - Zertifizierung KW - Digitale Transformation PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-554885 UR - https://www.qi-fokus.de SP - 1 EP - 44 PB - Bundesanstalt für Materialforschung und -prüfung (BAM) CY - Berlin AN - OPUS4-55488 LA - mul AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Koch, Claudia A1 - Ladu, Luana A1 - Asna Ashari, Parsa A1 - Blind, K. A1 - Castka, P. T1 - Digitalization in conformity assessment in Spain - A QI-FoKuS study N2 - This report summarizes findings from the first comprehensive study on digitalization in conformity assessment in Spain. The reults are based on data from a survey among conformity assessment bodies (CABs) conducted in 2022. It highlights the digital maturity of the organizations, the motives, benefits and obstacles of digital transformation as well as the actual technology trends. The study on Spanish CABs is part of a global project that covers various other countries (see www.qi-fokus.de). KW - COVID-19 KW - Calibration KW - Certification KW - Conformity assessment KW - Conformity assessment body KW - Digital transformation KW - Digitalization KW - Laboratory KW - Quality infrastructure KW - TIC KW - Testing PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-558465 UR - https://www.qi-fokus.de SP - 1 EP - 44 PB - Bundesanstalt für Materialforschung und -prüfung (BAM) CY - Berlin AN - OPUS4-55846 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Ladu, Luana A1 - Koch, Claudia A1 - Asna Ashari, Parsa A1 - Blind, K. A1 - Castka, P. T1 - Digitalization in conformity assessment in the Netherlands - A QI-FoKuS study N2 - This report summarizes findings from the first comprehensive study on digitalization in conformity assessment in the Netherlands. The reults are based on data from a survey among conformity assessment bodies (CABs) conducted in 2022. It highlights the digital maturity of the organizations, the motives, benefits and obstacles of digital transformation as well as the actual technology trends. The study on Dutch CABs is part of a global project that covers various other countries (see www.qi-fokus.de). KW - COVID-19 KW - Calibration KW - Certification KW - Conformity assessment KW - Conformity assessment body KW - Digital transformation KW - Digitalization KW - Laboratory KW - Quality infrastructure KW - TIC KW - Testing PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-555852 UR - https://www.qi-fokus.de SP - 1 EP - 44 PB - Bundesanstalt für Materialforschung und -prüfung (BAM) CY - Berlin AN - OPUS4-55585 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Koch, Claudia A1 - Ladu, Luana A1 - Asna Ashari, Parsa A1 - Blind, K. A1 - Castka, P. T1 - Digitalization in conformity assessment in Brazil - A QI-FoKuS study N2 - This report summarizes findings from the first comprehensive study on digitalization in conformity assessment in Brazil. The reults are based on data from a survey among conformity assessment bodies (CABs) conducted in 2022. It highlights the digital maturity of the organizations, the motives, benefits and obstacles of digital transformation as well as the actual technology trends. The study on Brazilian CABs is part of a global project that covers various other countries (see www.qi-fokus.de). KW - COVID-19 KW - Calibration KW - Certification KW - Conformity assessment KW - Conformity assessment body KW - Digital transformation KW - Digitalization KW - Laboratory KW - Quality infrastructure KW - TIC KW - Testing PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-556330 UR - https://www.qi-fokus.de SP - 1 EP - 44 PB - Bundesanstalt für Materialforschung und -prüfung (BAM) CY - Berlin AN - OPUS4-55633 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Koch, Claudia A1 - Ladu, Luana A1 - Asna Ashari, Parsa A1 - Blind, K. A1 - Castka, P. T1 - Digitalization in conformity assessment in Ireland - A QI-FoKuS study N2 - This report summarizes findings from the first comprehensive study on digitalization in conformity assessment in Ireland. The reults are based on data from a survey among conformity assessment bodies (CABs) conducted in 2022. It highlights the digital maturity of the organizations, the motives, benefits and obstacles of digital transformation as well as the actual technology trends. The study on Irish CABs is part of a global project that covers various other countries (see www.qi-fokus.de). KW - Quality infrastructure KW - Digitalization KW - Testing KW - Laboratory KW - Certification KW - Conformity assessment KW - Digital transformation KW - TIC KW - Conformity assessment body KW - COVID-19 KW - Calibration PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-554877 UR - https://www.qi-fokus.de SP - 1 EP - 44 PB - Bundesanstalt für Materialforschung und -prüfung (BAM) CY - Berlin AN - OPUS4-55487 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Koch, Claudia A1 - Ladu, Luana A1 - Asna Ashari, Parsa A1 - Blind, K. A1 - Castka, P. T1 - Digitalization in conformity assessment in Singapore - A QI-FoKuS study N2 - This report summarizes findings from the first comprehensive study on digitalization in conformity assessment in Singapore. The reults are based on data from a survey among conformity assessment bodies (CABs) conducted in 2022. It highlights the digital maturity of the organizations, the motives, benefits and obstacles of digital transformation as well as the actual technology trends. This study is part of a global project that covers various other countries (see www.qi-fokus.de). KW - COVID-19 KW - Calibration KW - Certification KW - Conformity assessment KW - Conformity assessment body KW - Digital transformation KW - Digitalization KW - Laboratory KW - Quality infrastructure KW - TIC KW - Testing PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-561363 UR - https://www.qi-fokus.de SP - 1 EP - 47 PB - Bundesanstalt für Materialforschung und -prüfung (BAM) CY - Berlin AN - OPUS4-56136 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Koch, Claudia A1 - Ladu, Luana A1 - Asna Ashari, Parsa A1 - Blind, K. A1 - Castka, P. T1 - Digitalization in conformity assessment in Latvia - A QI-FoKuS study N2 - This report summarizes findings from the first comprehensive study on digitalization in conformity assessment in Latvia. The reults are based on data from a survey among conformity assessment bodies (CABs) conducted in 2022. It highlights the digital maturity of the organizations, the motives, benefits and obstacles of digital transformation as well as the actual technology trends. The study on Latvian CABs is part of a global project that covers various other countries (see www.qi-fokus.de). KW - COVID-19 KW - Calibration KW - Certification KW - Conformity assessment KW - Conformity assessment body KW - Digital transformation KW - Digitalization KW - Laboratory KW - Quality infrastructure KW - TIC KW - Testing PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-554987 UR - https://www.qi-fokus.de SP - 1 EP - 45 PB - Bundesanstalt für Materialforschung und -prüfung (BAM) CY - Berlin AN - OPUS4-55498 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -