TY - JOUR A1 - Bertorelle, F. A1 - Wegner, Karl David A1 - Berkulic, M. P. A1 - Fakhouri, H. A1 - Comby-Zerbino, C. A1 - Sagar, A. A1 - Bernadó, P. A1 - Resch-Genger, Ute A1 - Bonacic-Koutecký, V. A1 - Le Guével, X. A1 - Antoine, R. T1 - Tailoring the NIR-II Photoluminescence of Single Thiolated Au25 Nanoclusters by Selective Binding to Proteins N2 - Atomically precise gold nanoclusters are a fascinating class of nanomaterials that exhibit molecule-like properties and have outstanding photoluminescence (PL). Their ultrasmall size, molecular chemistry, and biocompatibility make them extremely appealing for selective biomolecule labeling in investigations of biological mechanisms at the cellular and anatomical levels. In this work, we report a simple route to incorporate a preformed Au25 nanocluster into a model bovine serum albumin (BSA) protein. A new approach combining small-angle X-ray scattering and molecular modeling provides a clear localization of a single Au25 within the protein to a cysteine residue on the gold nanocluster surface. Attaching Au25 to BSA strikingly modifies the PL properties with enhancement and a redshift in the second near-infrared (NIR-II) window. This study paves the way to conrol the design of selective sensitive probes in biomolecules through a ligand-based strategy to enable the optical detection of biomolecules in a cellular environment by live imaging. KW - Fluorescence KW - Aggregation KW - Signal enhancement KW - Cluster KW - Nano KW - Metal KW - NIRII KW - SWIR KW - Sensor KW - Quantum yield KW - Lifetime KW - Photophysics KW - Synthesis KW - Protein KW - Imaging KW - Bioimaging KW - Ligand KW - Gold PY - 2022 DO - https://doi.org/10.1002/chem.202200570 SN - 1521-3765 VL - 28 IS - 39 SP - 1 EP - 8 PB - Wiley-VCH CY - Weinheim AN - OPUS4-55077 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Constantinescu, B. A1 - Bugoi, R. A1 - Cojocaru, V. A1 - Radtke, Martin A1 - Calligaro, T. A1 - Salomon, J. A1 - Pichon, L. A1 - Röhrs, S. A1 - Ceccato, D. A1 - Oberländer-Târnoveanu, E. T1 - Micro-SR-XRF and micro-PIXE studies for archaeological gold identification - The case of Carpathian (Transylvanian) gold and of Dacian bracelets N2 - Trace-elements are more significant for provenancing archaeological metallic artifacts than the main components. For gold, the most promising elements are platinum group elements (PGE), Sn, Te, Sb, Hg and Pb. Several small fragments of natural Transylvanian gold – placer and primary – were studied by using micro-PIXE technique at the Legnaro National Laboratory AN2000 microbeam facility, Italy and at the AGLAE accelerator, C2RMF, Paris, France and by using micro synchrotron radiation X-ray fluorescence (micro-SR-XRF) at BESSY synchrotron, Berlin, Germany. The goal of the study was to identify the trace-elements, especially Sn, Sb and Te. A spectacular application to five Dacian gold bracelets authentication is presented (Sn and Sb traces). KW - Micro-PIXE KW - Micro-SR-XRF KW - Gold KW - Dacian bracelets KW - Transylvania PY - 2008 DO - https://doi.org/10.1016/j.nimb.2008.03.054 SN - 0168-583X SN - 1872-9584 VL - 266 IS - 10 SP - 2325 EP - 2328 PB - Elsevier CY - Amsterdam AN - OPUS4-17736 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Constantinescu, B. A1 - Bugoi, R. A1 - Cojocaru, V. A1 - Radtke, Martin A1 - Calligaro, T. A1 - Salomon, J. A1 - Pichon, L. A1 - Röhrs, S. A1 - Ceccato, D. A1 - Oberländer-Târnoveanu, E. A1 - Ionescu, C. A1 - Pop, D. T1 - Dacian bracelets and Transylvanian gold: ancient history and modern analyses KW - SRXRF KW - Gold KW - Archaeometrie KW - Authentication KW - Provenance KW - XRF KW - Micro-PIXE KW - Micro SR-XRF KW - Or KW - Authentification KW - FX PY - 2009 SN - 0399-1237 VL - 33 SP - 221 EP - 225 PB - Groupe CY - Rennes AN - OPUS4-23172 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Constantinescu, B. A1 - Oberländer-Târnoveanu, E. A1 - Bugoi, R. A1 - Cojocaru, V. A1 - Radtke, Martin T1 - The Sarmizegetusa bracelets N2 - We present the authentication and analysis of these beautiful Dacian bracelets of the first century BC, originally pillaged by treasure hunters and recovered thanks to an international crime chase. They were originally fashioned from gold panned from the rivers or dug from the mines of Transylvania and hammered into the form of coiled snakes. The lack of context is the greatest loss, but a votive purpose is likely given their proximity to the great sacred centre at Sarmizegetusa Regia. KW - Romania KW - Sarmizegetusa KW - Dacian KW - First century BC KW - Gold KW - Bracelets KW - Hoard KW - Sacred centre KW - World heritage site PY - 2010 UR - http://antiquity.ac.uk/ant/084/ant0841028.htm SN - 0003-598x VL - 84 SP - 1028 EP - 1042 PB - Univ. Press CY - Oxford AN - OPUS4-23169 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Constantinescu, B. A1 - Vasilescu, A. A1 - Radtke, Martin A1 - Reinholz, Uwe T1 - A study on gold and copper provenance for Romanian prehistoric objects using micro-SR XRF N2 - This study intends to clarify the metal provenance of gold archaeological items using the variation of the Au–Ag ratio and the presence of trace elements as Sn, Sb, Te, and Pb, concentrating on gold Dacian Koson coins, recovered recently. It also extends the area of our investigations to the copper provenance of Bronze Age artifacts—axes, sickles, and celts—found on Romanian territory. The experiments were performed by micro-SR XRF at BESSY Berlin, at the BAM-line facility. Two types of coins (Koson, with and without monogram) were analysed. The conclusions we reached were that most of the monogram coins are made from refined gold (3–5% Ag, less than 0.5% Cu), while the without monogram coins are made from native Transylvanian gold (9–20% Ag, 0.5–2% Cu), of alluvial origin, proved by the presence of Sn, Sb and Te embedded in the gold. The problem of provenance for prehistoric Romanian copper and bronze objects consists in linking their elemental compositional patterns to the ones of the Bronze Age regional mines from Bulgaria, Serbia or Transylvania, most likely used as ore sources for their manufacture. The studied samples present relevant traces of As, Ag, Sb, and Co, suggesting the most probable use of copper from Serbia or northern Bulgaria for their manufacture. KW - X-ray fluorescence KW - Synchrotron radiation KW - Proton induced X-ray emission KW - Archaeometry KW - Gold PY - 2011 DO - https://doi.org/10.1039/c0ja00215a SN - 0267-9477 SN - 1364-5544 VL - 26 IS - 5 SP - 917 EP - 921 PB - Royal Society of Chemistry CY - London AN - OPUS4-23191 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Constantinescu, B. A1 - Vasilescu, A. A1 - Radtke, Martin A1 - Reinholz, Uwe T1 - Micro-SR-XRF studies for archaeological gold identification - the case of carpathian gold and romanian museal objects N2 - In the determination of the provenance of gold in archaeological artifacts, trace elements are more significant than the main components. Several minute fragments of natural Carpathian gold-placer and primary-and some very small (a few milligrams) fragments of archaeological items were studied using micro Synchrotron Radiation X-Ray Fluorescence (micro SR-XRF) at the BESSY Synchrotron Facility in Berlin, Germany. The goal of the study was to identify the trace elements characterizing Carpathian gold, looking especially at Sn, Sb, Pb and Te, and to determine if the gold in the archaeological items is native or refined. Applications to the authentication and provenance of nine Dacian gold bracelets, koson coins and two Bronze Age items are presented. KW - Gold KW - Provenance KW - Archeometry KW - Sy-XRF PY - 2010 DO - https://doi.org/10.1007/s00339-010-5624-1 SN - 0947-8396 VL - 99 IS - 2 SP - 383 EP - 389 PB - Springer CY - Berlin AN - OPUS4-21395 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Constantinescu, B. A1 - Vasilescu, A. A1 - Radtke, Martin A1 - Reinholz, Uwe A1 - Pacheco, C. A1 - Pichon, L. A1 - Oberländer-Târnoveanu, E. T1 - SR XRF and micro-PIXE studies on ancient metallurgy of thirteen Dacian gold bracelets N2 - A thorough microscopic investigation by SR XRF and micro-PIXE brings insight into the probable techniques used in the manufacture of thirteen Dacian gold bracelets, one of the most spectacular archaeological finds ever on the territory of Romania. KW - Micro-SR-XRF KW - Micro-PIXE KW - Archaeometry KW - Gold KW - Romania PY - 2012 DO - https://doi.org/10.1007/s00339-012-7306-7 SN - 0947-8396 VL - 109 IS - 2 SP - 395 EP - 402 PB - Springer CY - Berlin AN - OPUS4-26902 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Constantinescu, B. A1 - Vasilescu, A. A1 - Stan, D. A1 - Radtke, Martin A1 - Reinholz, Uwe A1 - Buzanich, Günter A1 - Ceccato, D. A1 - Oberländer-Târnoveanu, E. T1 - Studies on archaeological gold items found in Romanian territory using X-ray-based analytical spectrometry N2 - This paper is an overview of the work developed by our group in the investigations of museum objects and alluvial gold, reflected in a series of studies published between 2000–2011, supplemented with new results, unpublished up-to-date. The X-ray based spectrometric techniques employed range from various X-Ray Fluorescence (XRF) investigations to ion beam analysis, including synchrotron radiation XRF and micro-Particle Induced X-ray Emission. The gold objects discussed are mainly part of the Sarmizegetusa Dacian hoards—spiraled bracelets (armbands) and coins. After obtaining in 2011 the permission of the Romanian authorities to take very small (1–2 mg) samples from the most 'unimportant' areas of the Dacian bracelets and several Koson staters, to analyze them by micro-SR-XRF at BESSY, in February 2012, the investigation of several micro-areas of 17 stater and 28 bracelet samples revealed important micro-structural inhomogeneity, especially in Sn and Cu. The same inhomogeneous micro-structure has been seen in Transylvanian alluvial gold. The analyses revealed details on the fingerprint of geological gold deposits and also the main characteristics of ancient gold metallurgy procedures used by the Dacians: a relatively low temperature (lower than Au melting point) and hammering during heating to obtain an ingot through sintering. The use of the sintering procedure was proved for the spiraled bracelets and the Koson without monogram coins, a tradition starting in the Bronze Age in Transylvanian gold processing. The existence of micro-inclusions of Ta-minerals in alluvial gold was also detected, explaining Ta trace presence in the artifacts from the Pietroasa hoard. KW - Micro-SR-XRF KW - Micro-PIXE KW - Archaeometry KW - Gold KW - Romania PY - 2012 DO - https://doi.org/10.1039/c2ja30158j SN - 0267-9477 SN - 1364-5544 VL - 27 IS - 12 SP - 2076 EP - 2081 PB - Royal Society of Chemistry CY - London AN - OPUS4-26991 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dietrich, Paul A1 - Graf, Nora A1 - Gross, Thomas A1 - Lippitz, Andreas A1 - Schüpbach, B. A1 - Bashir, A. A1 - Wöll, Ch. A1 - Terfort, A. A1 - Unger, Wolfgang T1 - Self-assembled monolayers of aromatic omega-aminothiols on gold: surface chemistry and reactivity N2 - Amino-terminated self-assembled monolayers on gold substrates were studied by X-ray photoelectron spectroscopy (XPS), near-edge X-ray absorption fine structure (NEXAFS) measurements, and atomic force microscopy (AFM). Two different ω-amino-4,4'-terphenyl substituted alkanethiols of the general structure H2N-(C6H4)3-(CH2)n-SH (ATPn) were used: 2-(4''-amino-1,1':4',1''-terphenyl-4-yl)ethane-1-thiol (n = 2, ATP2) and 3-(4''-amino-1,1':4',1''-terphenyl-4-yl)propane-1-thiol (n = 3, ATP3). Moreover, the addressability of amino groups within the films was investigated by chemical derivatization of ATPn SAMs with 3,5-bis(trifluoromethyl)phenyl isothiocyanate (ITC) forming fluorinated thiourea ATPn-F films. Evaluation of high-resolution C 1s and N 1s XPS data revealed successful derivatization of at least 50% of surface amino species. Furthermore, it could be demonstrated by angle-resolved NEXAFS spectroscopy that chemical derivatization with ITC has no noticeable influence on the preferential upright orientation of the molecules in the SAMs. KW - Gold KW - Self-assembled monolayer KW - Thiols KW - Amino surfaces KW - XPS KW - NEXAFS PY - 2010 DO - https://doi.org/10.1021/la903293b SN - 0743-7463 SN - 1520-5827 VL - 26 IS - 6 SP - 3949 EP - 3954 PB - American Chemical Society CY - Washington, DC AN - OPUS4-20990 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Eichelbaum, M. A1 - Kneipp, Janina A1 - Schmidt, B.E. A1 - Panne, Ulrich A1 - Rademann, K. T1 - SERS and Multiphoton-Induced Luminescence of Gold Micro- and Nanostructures Fabricated by NIR Femtosecond-Laser Irradiation KW - Gold KW - Luminescence KW - Multiphoton fabrication KW - Sol-gel processes KW - Surface-enhanced Raman scattering PY - 2008 DO - https://doi.org/10.1002/cphc.200800417 SN - 1439-4235 SN - 1439-7641 VL - 9 IS - 15 SP - 2163 EP - 2167 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-18233 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gauert, C. A1 - Schannor, M. A1 - Hecht, L. A1 - Radtke, Martin A1 - Reinholz, Uwe T1 - A comparison of in situ analytical methods for trace element measurement in gold samples from various South African gold deposits N2 - Trace element concentrations in gold grains from various geological units in South Africa were measured in situ by field emission-electron probe microanalysis (FE-EPMA), laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) and synchrotron micro X-ray fluorescence spectroscopy (SR-µ-XRF). This study assesses the accuracy, precision and detection limits of these mostly non-destructive analytical methods using certified reference materials and discusses their application in natural sample measurement. FE-EPMA point analyses yielded reproducible and discernible concentrations for Au and trace concentrations of S, Cu, Ti, Hg, Fe and Ni, with detection limits well below the actual concentrations in the gold. LA-ICP-MS analyses required larger gold particles (> 60 µm) to avoid contamination during measurement. Elements that measured above detection limits included Ag, Cu, Ti, Fe, Pt, Pd, Mn, Cr, Ni, Sn, Hg, Pb, As and Te, which can be used for geochemical characterisation and gold fingerprinting. Although LA-ICP-MS measurements had lower detection limits, precision was lower than FE-EPMA and SR-µ-XRF. The higher variability in absolute values measured by LA-ICP-MS, possibly due to micro-inclusions, had to be critically assessed. Non-destructive point analyses of gold alloys by SR-µ-XRF revealed Ag, Fe, Cu, Ni, Pb, Ti, Sb, U, Cr, Co, As, Y and Zr in the various gold samples. Detection limits were mostly lower than those for elements measured by FE-EPMA, but higher than those for elements measured by LA-ICP-MS. N2 - Les concentrations en éléments traces de grains d'or provenant de différentes unités géologiques d'Afrique du Sud ont été mesurées in situ par microsonde électronique à émission de champ (FE-EPMA), spectrométrie de masse couplée à une source plasma et un système d'ablation laser (LA-ICP-MS) et micro spectroscopie de fluorescence des rayons X au Synchrotron (SR-µ-XRF). Cette étude évalue l'exactitude, la précision et les limites de détection de ces méthodes d'analyse pour la plupart non-destructives en utilisant des matériaux de référence certifiés, et discute de leur application dans les mesures sur échantillon naturel. Les points d'analyses FE-EPMA ont fournis des concentrations reproductibles et discernables pour l'Au et des concentrations en traces de S, Cu, Ti, Hg, Fe et Ni, avec des limites de détection bien inférieures aux concentrations réelles dans l'or. Les analyses LA-ICP-MS ont nécessitées des particules d'or de plus grande taille (> 60 µm) pour éviter toute contamination pendant la mesure. Les éléments mesurés au-dessus des limites de détection inclus Ag, Cu, Ti, Fe, Pt, Pd, Mn, Cr, Ni, Sn, Hg, Pb, A et Te, qui peuvent être utilisés pour les caractérisations géochimique et le «fingerprinting» de l'or. Bien que les mesures LA-ICP-MS aient des limites de détection plus basses, la précision est inférieure par rapport à celles de la microsonde FE et de la SR-µ-XRF. La plus grande variabilité des valeurs absolues mesurées par LA-ICP-MS, probablement reliée à la présence de micro-inclusions, a du être évaluée de manière critique. Les points d'analyse non-destructifs des alliages d'or par SR-µ-XRF ont révélés la présence de Ag, Fe, Cu, Ni, Pb, Ti, Sb, U, Cr, Co, As, Y et Zr dans les différents échantillons. Les limites de détection ont été pour la plupart inférieures à celles des éléments mesurés par FE-EPMA, mais supérieures à celles des éléments mesurés par LA-ICP-MS. KW - Trace elements KW - Gold KW - FE-EPMA KW - LA-ICP-MS KW - SR-µ-XRF KW - Precision KW - Précision KW - Comparison of techniques KW - Éléments traces PY - 2016 DO - https://doi.org/10.1111/j.1751-908X.2015.00362.x SN - 1639-4488 SN - 1751-908X VL - 40 IS - 2 SP - 267 EP - 289 PB - Blackwell CY - Oxford AN - OPUS4-34882 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Guerra, M. F. A1 - Fischer, M. A1 - Radtke, Martin A1 - Reinholz, Uwe T1 - Inca figurines from the Ethnologisches Museum in Berlin: an analytical study of some typical and atypical productions N2 - Fourteen hollow and one cast anthropomorphic and zoomorphic figurines produced in Incan times for ritual offerings from the Ethnologisches Museum in Berlin were selected to investigate the technologies and alloys used for their fabrication with portable optical microscopy and non-destructive XRF elemental analysis. This group of gold and silver figurines includes typical specimens of the Inca production, such as the four silver figurines from the Island Coati in Lake Titicaca and the two gold figurines from Pachacamac, as well as specimens that are seldom present in collections, which makes them atypical. In addition to the tall figurines with atypical hair or standing pose, one bicolour figurine half silver, half gold) and another with coloured inlays were included in this study for comparison. The large majority of the silver specimens are made from very high quality alloys and the gold figurines are made from alloys containing low copper contents and silver ranging from 30wt% to 52wt%. KW - Gold KW - pXRF KW - Inca PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-436015 DO - https://doi.org/10.4000/bifea.8232 SN - 0303-7495 VL - 46 IS - 1 SP - 221 EP - 251 PB - Institut Français d'Études Andines AN - OPUS4-43601 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Guerra, M. F. A1 - Radtke, Martin A1 - Reiche, I. A1 - Riesemeier, Heinrich A1 - Strub, Erik T1 - Analysis of trace elements in gold alloys by SR-XRF at high energy at the BAMline N2 - Measuring in a non-destructive way the characteristic trace elements of the metal allows following the circulation of gold in the past. The aim of this work is to probe the possibilities of X-ray fluorescence with high energy synchrotron radiation (SR-XRF) at the BAMline at BESSY II to determine the concentration of Pt in ancient gold alloys. A HP-Ge detector was used to measure the Pt K-lines excited with an incident energy of 79.5 keV. Data processing was done by subtraction of a Pt free gold standard spectrum from the spectrum of the sample. Depending on the sample composition, the MDL ranges between 40 and 90 ppm. The first results obtained for a small set of gold alloys of different thickness, size and composition showed that high energy SR-XRF is a significant method for the non-destructive determination of Pt in gold. KW - SR-XRF KW - Gold KW - Provenancing KW - Trace elements PY - 2008 DO - https://doi.org/10.1016/j.nimb.2008.03.008 SN - 0168-583X SN - 1872-9584 VL - 266 IS - 10 SP - 2334 EP - 2338 PB - Elsevier CY - Amsterdam AN - OPUS4-17735 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Guerra, M.F. A1 - Neri, E. A1 - Radtke, Martin T1 - Gold leaf tesserae: tracing the origins of gold using synchrotron-based techniques N2 - To gain insight into the possible origin of the gold used in the production of tesserae containing gold leaf less than 0.5 μm thick placed between two layers of glass, we propose a non-destructive synchrotron radiation (SR) XRF protocol based on sequential analysis under optimised analytical conditions. Using this protocol, trace element analysis is achieved with detection limits of 1–6 mg/kg. As Pt and Au have adjacent fluorescence energies, we tested the most challenging situation, when Pt is present in very low concentrations in gold. Data obtained by double-dispersive XRF (D2XRF) and μXRF for fourth–ninth-century mosaics decorating nine Eastern and Western religious buildings show that the Eastern and Western tesserae are made from different alloys. However, these alloys are identical to those used to make gold leaf for gilding, because plastic deformation requires the use of gold alloys with high ductility and malleability. Although trace element composition of gold used in the concerned period is only available for coins, by comparing the amounts of Pt contained in the tesserae and in the coins we show that Roman tesserae are made from Roman gold, as described in the documentary sources. We observe for the Byzantine period the use of a Byzantine gold and of gold supposedly from different stages of recycling, and we suggest the use of Umayyad and Abbasid gold for the production of Islamic tesserae. KW - Gold KW - XRF KW - Synchrotron KW - BAMline KW - D2XRF KW - Tesserae PY - 2023 DO - https://doi.org/10.1140/epjp/s13360-022-03638-y SN - 2190-5444 VL - 138 IS - 2 SP - 1 EP - 15 AN - OPUS4-57208 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Handrea-Haller, Marlene A1 - Sahre, Mario A1 - Kautek, Wolfgang A1 - Neubauer, A. A1 - Sleytr, U.B. T1 - Electrochemistry of nano-scale bacterial surface protein layers on gold N2 - The mechanism of the recrystallization of nano-scale bacterial surface protein layers (S-layers) on solid substrates is of fundamental interest in the understanding and engineering of biomembranes and e.g. biosensors. In this context, the influence of the charging state of the substrate had to be clarified. Therefore, the electrochemical behaviour of the S-layers on gold electrodes has been investigated by in-situ electrochemical quartz microbalance (EQMB) measurements, scanning force microscopy (SFM) and small-spot X-ray photoelectron spectroscopy (SS-XPS) of potentiostatically emersed substrates. It was shown that the negatively charged bonding sites of the S-layer units (e.g. carboxylates) can bond with positively charged Au surface atoms in the positively charged electrochemical double layer region positive of the point of zero charge (not, vert, similar-0.8 V vs. saturated mercury-mercurous sulphate electrode). Surface conditions in other potential regions decelerated the recrystallization and fixation of S-layers. Time-resolved in-situ and ex-situ measurements demonstrated that two-dimensional S-layer crystal formation on gold electrodes can occur within few minutes in contrast to hours common in self-assembled monolayer (SAM) generation. These results proved that the recrystallization and fixation of 2D-crystalline S-layers on an electronic conductor can be influenced and controlled by direct electrochemical manipulation. KW - S-layers crystallization KW - Gold KW - Electrochemical quartz microbalance KW - Scanning force microscopy KW - XPS PY - 2003 DO - https://doi.org/10.1016/S1567-5394(03)00047-1 SN - 0302-4598 SN - 1567-5394 VL - 61 SP - 1 EP - 8 PB - Elsevier Science CY - Oxford AN - OPUS4-2844 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Handrea-Haller, Marlene A1 - Sahre, Mario A1 - Neubauer, A. A1 - Sleytr, U.B. A1 - Kautek, Wolfgang T1 - Electrochemistry of Nano-Scale Bacterial Surface Protein Layers on Gold KW - S-layers crystallization KW - Gold KW - Electrochemical quartz microbalance KW - Scanning force microscopy KW - XPS PY - 2002 SN - 0013-4686 SN - 1873-3859 N1 - Geburtsname von Handrea-Haller, Marlene: Handrea, M. - Birth name of Handrea-Haller, Marlene: Handrea, M. PB - Elsevier Science CY - Kidlington AN - OPUS4-1736 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Henrichsen, H. A1 - Sturm, Heinz A1 - Boggild, P. A1 - Hansen, O. T1 - Submicron organic nanofiber devices with different anode-cathode materials: A simple approach N2 - The authors present a simple general method for simultaneously producing tens of submicron electrode gaps with different cathode and anode materials on top of nanofibers, nanowires, and nanotubes, with an optional gap size variation. Using this method, an ensemble of para-hexaphenylene (p6P) nanofiber devices of different length was fabricated with Sm and Au electrodes. The measured I-V characteristics are in agreement with a nonlinear hopping transport model, where domain barriers dominate the transport with an estimated domain size of 23±5 nm. KW - Nanofibers KW - Sub-micron electrode KW - Para-hexaphenylene KW - Samarium KW - Gold KW - I/V-characteristics KW - Nanolasers KW - Domain barriers PY - 2010 DO - https://doi.org/10.1116/1.3431088 SN - 1071-1023 SN - 0734-211X VL - 28 IS - 3 SP - 617 EP - 622 PB - American Institute of Physics CY - New York, NY AN - OPUS4-21573 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hildebrandt, Jana A1 - Taubert, Andreas A1 - Thünemann, Andreas T1 - Synthesis and Characterization of Ultra‐Small Gold Nanoparticles in the Ionic Liquid 1‐Ethyl‐3‐methylimidazolium Dicyanamide, [Emim][DCA] N2 - AbstractWe report on gold clusters with around 62 gold atoms and a diameter of 1.15±0.10 nm. Dispersions of the clusters are long‐term stable for two years at ambient conditions. The synthesis was performed by mixing tetrachloroauric acid (HAuCl4 ⋅ 3 H2O) with the ionic liquid 1‐ethyl‐3‐methylimidazolium dicyanamide ([Emim][DCA]) at temperatures of 20 to 80 °C. Characterization was performed with small‐angle X‐ray scattering (SAXS), UV‐Vis spectroscopy, and MALDI‐TOF mass spectrometry. A three‐stage model is proposed for the formation of the clusters, in which cluster growth from gold nuclei takes place according to the Lifshitz‐Slyozov‐Wagner (LSW) model followed by oriented attachment to form colloidal stable clusters. KW - Reference materials KW - SAXS KW - Gold KW - Nanoparticle KW - Small-angle X-ray scattering KW - Ionic liquid PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-588203 DO - https://doi.org/10.1002/open.202300106 SN - 2191-1363 VL - 44 SP - 1 EP - 19 PB - Wiley AN - OPUS4-58820 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kaiser, J. A1 - Szczerba, Wojciech A1 - Riesemeier, Heinrich A1 - Reinholz, Uwe A1 - Radtke, Martin A1 - Albrecht, M. A1 - Lu, Y. A1 - Ballauff, M. T1 - The structure of AuPd nanoalloys anchored on spherical polyelectrolyte brushes determined by x-ray absorption spectroscopy N2 - Well-defined and facetted bimetallic gold–palladium nanoalloys have been synthesized and anchored in spherical polyelectrolyte brushes (SPB) as composite particles (AuPd@SPB). These particles are better catalysts in aqueous phase than the pure metals. The atomistic arrangement of these nanoalloys has been analysed by extended X-ray absorption fine structure (EXAFS) spectroscopy at the Au–L3 and the Pd–K absorption edge. The samples with high amounts of gold appear as almost statistically mixed random alloys. Alloy compositions with less gold show slight enrichment of Pd at the surface of the particle. In addition, signals of non-metallic palladium appear at the Pd–K edge which indicate the presence of the Pd2+ species in addition to metallic palladium. The relation of these structural features to the catalytic activity is discussed. KW - EXAFS KW - Nanoalloys KW - Gold KW - Palladium KW - K-edge KW - L3-edge KW - HR-TEM KW - Synchrotron radiation KW - BAMline PY - 2013 DO - https://doi.org/10.1039/c3fd20132e SN - 1359-6640 SN - 1364-5498 VL - 162 SP - 45 EP - 55 PB - Soc. CY - Cambridge [u.a.] AN - OPUS4-28300 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kautek, Wolfgang A1 - Reetz, Susanne A1 - Pentzien, Simone T1 - Template Electrodeposition of Nanowire Arrays on Gold Foils Fabricated by Pulsed-Laser Deposition KW - Nanodraht KW - Gold KW - Galvanisierung, elektrisch KW - Verbundwerkstoff KW - Laser KW - Impulslaser PY - 1995 SN - 0013-4686 SN - 1873-3859 VL - 40 IS - 10 SP - 1461 EP - 1468 PB - Elsevier Science CY - Kidlington AN - OPUS4-626 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -