TY - JOUR
A1 - Denker, A.
A1 - Hahn, Oliver
A1 - Merchel, Silke
A1 - Radtke, Martin
A1 - Kanngießer, B.
A1 - Malzer, W.
A1 - Röhrs, S.
A1 - Reiche, I.
A1 - Stege, H.
T1 - Röntgenanalytik für Kunstwerke und Kulturgüter
N2 - Naturwissenschaftler arbeiten mit Archäologen, Kunsthistorikern und Restauratoren zusammen, um Materialinformationen über Kunstwerke mit den Erkenntnissen aus Altertumsforschung, Kunstgeschichte und Denkmalpflege zu verbinden. Röntgenfluoreszenz und Röntgenemission sind die Methoden der Wahl, wenn wertvolle und fragile Objekte zerstörungsfrei zu untersuchen sind.
KW - Synchrotron
KW - XRF analysis
KW - Drawings
KW - Paintings
KW - Ink
KW - Art objects
KW - Archaeometry
KW - Röntgenfluoreszenzanalyse (RFA)
KW - Zeichnungen
KW - Gemälde
KW - Tinten
KW - Kunstobjekte
KW - Archäometrie
PY - 2005
SN - 1439-9598
SN - 1521-3854
VL - 53
IS - 2
SP - 118
EP - 123
PB - Wiley-VCH Verl.
CY - Weinheim
AN - OPUS4-6898
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wilhelm, Stefan
A1 - Kaiser, Martin
A1 - Würth, Christian
A1 - Heiland, J.
A1 - Carrillo-Carrion, C.
A1 - Muhr, V.
A1 - Wolfbeis, Otto S.
A1 - Parak, W.J.
A1 - Resch-Genger, Ute
A1 - Hirsch, T.
T1 - Water dispersible upconverting nanoparticles: effects of surface modification on their luminescence and colloidal stability
N2 - We present a systematic study on the effect of surface ligands on the luminescence properties and colloidal stability of β-NaYF4:Yb3+,Er3+ upconversion nanoparticles (UCNPs), comparing nine different surface coatings to render these UCNPs water-dispersible and bioconjugatable. A prerequisite for this study was a large-scale synthetic method that yields ~2 g per batch of monodisperse oleate-capped UCNPs providing identical core particles. These ~23 nm sized UCNPs display an upconversion quantum yield of ~0.35% when dispersed in cyclohexane and excited with a power density of 150 W cm-2, underlining their high quality. A comparison of the colloidal stability and luminescence properties of these UCNPs, subsequently surface modified with ligand exchange or encapsulation protocols, revealed that the ratio of the green (545 nm) and red (658 nm) emission bands determined at a constant excitation power density clearly depends on the surface chemistry. Modifications relying on the deposition of additional (amphiphilic) layer coatings, where the initial oleate coating is retained, show reduced non-radiative quenching by water as compared to UCNPs that are rendered water-dispersible via ligand exchange. Moreover, we could demonstrate that the brightness of the upconversion luminescence of the UCNPs is strongly affected by the type of surface modification, i.e., ligand exchange or encapsulation, yet hardly by the chemical nature of the ligand.
KW - upconverting nanoparticles (UCNPs)
KW - Luminescence
KW - surface modification
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-324071
DO - https://doi.org/10.1039/c4nr05954a
SN - 2040-3364
SN - 2040-3372
VL - 7
IS - 4
SP - 1403
EP - 1410
PB - RSC Publ.
CY - Cambridge
AN - OPUS4-32407
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fittschen, U.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Böttger, S.
A1 - Rosenberg, D.
A1 - Menzel, M.
A1 - Jensen, W.
A1 - Busker, M.
A1 - Gotlib, Z.
A1 - Radtke, Martin
A1 - Riesemeier, Heinrich
A1 - Wobrauschek, P.
A1 - Streli, C.
ED - de Oliveira Guilherme Buzanich, Ana
T1 - A setup for synchrotron-radiation-induced total reflection X-ray fluorescence and X-ray absorption near-edge structure recently commissioned at BESSY II BAMline
N2 - An automatic sample changer chamber for total reflection X-ray fluorescence (TXRF) and X-ray absorption near-edge structure (XANES) analysis in TXRF geometry was successfully set up at the BAMline at BESSY II. TXRF and TXRF-XANES are valuable tools for elemental determination and speciation, especially where sample amounts are limited (<1 mg) and concentrations are low (ng ml⁻¹ to μg ml⁻¹). TXRF requires a well defined geometry regarding the reflecting surface of a sample carrier and the synchrotron beam. The newly installed chamber allows for reliable sample positioning, remote sample changing and evacuation of the fluorescence beam path. The chamber was successfully used showing accurate determination of elemental amounts in the certified reference material NISTwater 1640. Low limits of detection of less than 100 fg absolute (10 pg ml⁻¹) for Ni were found. TXRF-XANES on different Re species was applied. An unknown species of Re was found to be Re in the +7 oxidation state.
KW - TXRF
KW - TXRF-XANES
KW - Sample changer
KW - BAMline
KW - Re-XANES
PY - 2016
DO - https://doi.org/10.1107/S1600577516001995
SN - 1600-5775
VL - 23
IS - 3
SP - 820
EP - 824
PB - International Union of Crystallography
AN - OPUS4-38656
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Menzel, M.
A1 - Scharf, O.
A1 - Novak, S.
A1 - Radtke, Martin
A1 - Reinholz, Uwe
A1 - Hischenhuber, P.
A1 - Buzanich, Günter
A1 - Meyer, A.
A1 - Lopez, V.
A1 - McIntosh, K.
A1 - Streli, C.
A1 - Havrilla, G.
A1 - Fittschen, U.
T1 - Shading in TXRF: calculations and experimental validation using a color X-ray camera
N2 - Absorption effects in total reflection X-ray fluorescence (TXRF) analysis are important to consider, especially if external calibration is to be applied. With a color X-ray camera (CXC), that enables spatially and energy resolved XRF analysis, the absorption of the primary beam was directly visualized for mL-droplets and an array of pL-droplets printed on a Si-wafer with drop-on-demand technology. As expected, deposits that are hit by the primary beam first shade subsequent droplets, leading to a diminished XRF signal. This shading effect was quantified with enhanced precision making use of sub-pixel analysis that improves the spatial resolution of the camera. The measured absorption was compared to simulated results using three different model calculations. It was found they match very well (average deviation < 10%). Thus errors in quantification due to absorption effects can be accounted for in a more accurate manner.
KW - absorption
KW - X-ray Fluorescence analysis
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-359000
DO - https://doi.org/10.1039/C5JA00127G
IS - 10
SP - 2184
EP - 2193
PB - Royal Society of Chemistry
CY - Cambridge
AN - OPUS4-35900
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Hahn, Oliver
A1 - Denker, A.
A1 - Merchel, S.
A1 - Radtke, Martin
A1 - Reinholz, Uwe
A1 - Wolff, T.
ED - Armbruster, B.
ED - Eilbracht, H.
ED - Hahn, Oliver
ED - Heinrich-Tamaska, O.
T1 - Zerstörungsfreie Analyse von Metallartefakten - Eine Fallstudie
N2 - Die naturwissenschaftliche Analyse historischer Materialen ermöglicht die Beantwortung kulturhistorischer Fragestellungen, die mit kunsthistorischen oder archäologischen Ansätzen allein nicht zu leisten sind. In dieser Studie wurden sechs römische Münzen mit unterschiedlich stark ausgeprägten Korrosionsschichten an unbehandelten und polierten Stellen mit vier zerstörungsfreien analytischen Methoden untersucht: Hoch- und Niederenergie Protonen Induzierter Röntgenemission (HE-/PIXE), Synchrotronstrahlungsinduzierte-Röntgenfluoreszenzanalyse (SY-RFA) und Mikro-Röntgenfluoreszenzanalyse (Mikro-RFA) mit einem mobilen Gerät. Aufgrund von Unterschieden in den Messbedingungen und dem Einfluss der Patina-Schichten auf diese ergaben sich nur für wenige Elemente Übereinstimmungen in den quantitativen Daten. Zur Validierung zukünftiger Messkampagnen mit verschiedenen Methoden sind daher Vergleichstudien unerlässlich.
N2 - Investigations of physical properties and chemical composition of ancient materials generate important data for answering culture-historical questions that cannot be solved by art historical and archaeological methods alone. This contribution reports on the analysis of six Roman coins, with different degrees of corrosion layers in parts that were not handled or polished, using four non-destructive methods: low-energy particle-induced X-ray emission (PIXE, 2 MeV), high-energy PIXE (68 MeV), μ-X-ray fluorescence (XRF) spectrometry with a portable device and synchrotron-radiation induced XRF. Because of differences in the conditions needed for measurement and the influence of the layers of patina on these measurements, there were few elements where the quantitative data were in agreement. Thus comparative analyses are essential to validate future measurement projects using different methods.
KW - Zerstörungsfreie Prüfung
KW - Protoneninduzierte Röntgenemission
KW - Röntgenfluoreszenzanalyse
KW - Non-destructive testing
KW - Particle-induced X-ray emission
KW - X-ray fluorescence analysis
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-385702
SN - 978-3-9816751-5-3
VL - Berlin studies of the ancient world, Band 35
SP - 117
EP - 137
PB - Edition Topoi
CY - Berlin
AN - OPUS4-38570
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - de O. Primo, J.
A1 - Horsth, D.F.
A1 - de S. Correa, J.
A1 - Das, A.
A1 - Bittencourt, C.
A1 - Umek, P.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Radtke, Martin
A1 - Yusenko, Kirill
A1 - Zanetta, C.
A1 - Anaissi, F.J.
T1 - Synthesis and Characterization of Ag/ZnO Nanoparticles for Bacteria Disinfection in Water
N2 - n this study, two green synthesis routes were used for the synthesis of Ag/ZnO nanoparticles, using cassava starch as a simple and low-cost effective fuel and Aloe vera as a reducing and stabilizing agent. The Ag/ZnO nanoparticles were characterized and used for bacterial dis-
infection of lake water contaminated with Escherichia coli (E. coli). Characterization indicated the formation of a face-centered cubic structure of metallic silver nanoparticles with no insertion of Ag into the ZnO hexagonal wurtzite structure. Physicochemical and bacteriological analyses described in “Standard Methods for the Examination of Water and Wastewater” were used to evaluate the efficiency of the treatment. In comparison to pure ZnO, the synthesized Ag/ZnO nanoparticles showed high efficiencies against Escherichia coli (E. coli) and general coliforms present in the lake
water. These pathogens were absent after treatment using Ag/ZnO nanoparticles. The results indicate that Ag/ZnO nanoparticles synthesized via green chemistry are a promising candidate for the treatment of wastewaters contaminated by bacteria, due to their facile preparation, low-cost synthesis,and disinfection efficiency.
KW - Synchrotron
KW - BAMline
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-562440
DO - https://doi.org/10.3390/nano12101764
SN - 2079-4991
VL - 12
IS - 10
SP - 1
EP - 18
PB - MDPI
CY - Basel
AN - OPUS4-56244
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gomes, Bruna F.
A1 - Prokop, Martin
A1 - Bystron, Tomas
A1 - Loukrakpam, Rameshwori
A1 - Melke, Julia
A1 - Lobo, Carlos M. S.
A1 - Fink, Michael
A1 - Zhu, Mengshu
A1 - Voloshina, Elena
A1 - Kutter, Maximilian
A1 - Hoffmann, Hendrik
A1 - Yusenko, Kirill V.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Röder, Bettina
A1 - Bouzek, Karel
A1 - Paulus, Beate
A1 - Roth, Christina
T1 - Following Adsorbed Intermediates on a Platinum Gas Diffusion Electrode in H3PO3-Containing Electrolytes Using In Situ X-ray Absorption Spectroscopy
N2 - One of the challenges of high-temperature polymer electrolyte membrane fuel cells is the poisoning of the Pt catalystwith H3PO4. H3PO4 is imbibed into the routinely used polybenzimidazole-based membranes, which facilitate Proton conductivity in the temperature range of 120−200 °C. However, when leached out of the membrane by water produced during operation, H3PO4 adsorbs on the Pt catalyst surface, blocking the active sites and hindering the oxygen reduction reaction (ORR).
The reduction of H3PO4 to H3PO3, which occurs at the anode due to a combination of a low potential and the presence of gaseous H2, has been investigated as an additional important contributing factor to the observed poisoning effect. H3PO3 has an affinity toward adsorption on Pt surfaces even greater than that of H2PO4 −. In this work, we investigated the poisoning effect of both H3PO3 and H3PO4 using a half-cell setup with a gas diffusion electrode under ambient conditions. By means of in situ X-ray absorption spectroscopy, it was possible to follow the signature of different species adsorbed on the Pt nanoparticle catalyst (H, O, H2PO4 −, and H3PO3) at different potentials under ORR conditions in various electrolytes (HClO4, H3PO4, and H3PO3). It was found that H3PO3 adsorbs in a pyramidal configuration P(OH)3 through a Pt−P bond. The competition between H3PO4 and H3PO3 adsorption was studied, which should allow for a better understanding of the catalyst poisoning mechanism and thus assist in the development of strategies to mitigate this phenomenon in the future by minimizing H3PO3 generation by, for example, improved catalyst design or adapted operation conditions or changes in the electrolyte composition.
KW - H3PO4 life cycle
KW - XAS
KW - In situ coupling
KW - High-temperature fuel cells
KW - H3PO3,
KW - Δμ XANES
PY - 2022
DO - https://doi.org/10.1021/acscatal.2c02630
SN - 2155-5435
VL - 12
IS - 18
SP - 11472
EP - 11484
PB - American Chemical Society (ACS)
AN - OPUS4-64733
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - INPR
A1 - Nowak, S. H.
A1 - Petric, M.
A1 - Buchriegler, J.
A1 - Bjeoumikhov, A.
A1 - Bjeoumikhova, Z.
A1 - von Borany, J.
A1 - Munnik, F.
A1 - Radtke, Martin
A1 - Renno, A. D.
A1 - Reinholz, Uwe
A1 - Scharf, O.
A1 - Tilgner, J.
A1 - Wedell, R.
T1 - Road to micron resolution with a color X-ray camera - Polycapillary optics characterization
N2 - In a color X-ray camera spatial resolution is achieved by means of a polycapillary optic conducting X-ray photons from small regions on a sample to distinct energy dispersive pixels on a CCD matrix. At present, the resolution limit of color X-ray camera systems can go down to several microns and is mainly restricted by Pixel dimensions. The recent development of an efficient subpixel resolution algorithm allows a release from pixel size, limiting the resolution only to the quality of theoptics. In this work polycapillary properties that influence the spatial resolution are systematized and assessed both theoretically and experimentally. It is demonstrated that with the current technological Level reaching one micron resolution is challenging, but possible.
KW - Color X-ray camera
KW - Polycapillary optics
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-404404
DO - https://doi.org/10.48550/arXiv.1705.08939
SN - 2331-8422
SP - 1
EP - 11
PB - Cornell University
CY - Ithaca, NY
AN - OPUS4-40440
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Kulow, Anicó
A1 - Kabelitz, Anke
A1 - Grunewald, C.
A1 - Seidel, R.
A1 - Chapartegui-Arias, Ander
A1 - Radtke, Martin
A1 - Reinholz, Uwe
A1 - Emmerling, Franziska
A1 - Beyer, S.
T1 - Observation of early ZIF-8 crystallization stages with X-ray absorption spectroscopy
N2 - The present study investigates early stages of ZIF-8 crystallization up to 5 minutes post mixing of precursor solutions. Dispersive X-ray Absorption Spectroscopy (DXAS) provides a refined understanding of the evolution of the coordination environment during ZIF-8 crystallization. Linear Combination Fiting (LCF) suggests tetrakis(1-methylimidazole)zinc2+ to be a suitable and stable mononuclear structure analogue for some early stage ZIF-8 intermediates. Our results pave the way for more detailed studies on physico-chemical aspects of ZIF-8 crystallization to better control tailoring ZIF-8 materials for specific applications.
KW - In-situ
KW - XANES
KW - ZIF-8
KW - Crystallization
PY - 2020
DO - https://doi.org/10.1039/D0SM01356K
SN - 1744-6848
VL - 17
IS - 2
SP - 331
EP - 334
PB - Royal Scociety of Chemistry
AN - OPUS4-51723
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - C. Pardo Pérez, L.
A1 - Arndt, A.
A1 - Stojkovikj, S.
A1 - Y. Ahmet, I.
A1 - T. Arens,, J.
A1 - Dattila, F.
A1 - Wendt, R.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Radtke, Martin
A1 - Davies, V.
A1 - Höflich, K.
A1 - Köhnen, E.
A1 - Tockhorn, P.
A1 - Golnak, R.
A1 - Xiao, J.
A1 - Schuck, G.
A1 - Wollgarten, M.
A1 - López, N.
A1 - T. Mayer, M.
T1 - Determining Structure-Activity Relationships in Oxide Derived CuSn Catalysts During CO2 Electroreduction Using X-Ray Spectroscopy
N2 - The development of earth-abundant catalysts for selective electrochemical CO2 conversion is a central challenge. Cu-Sn bimetallic catalysts can yield selective CO2 reduction toward either CO or formate. This study presents oxide-derived Cu-Sn catalysts tunable for either product and seeks to understand the synergetic effects between Cu and Sn causing these selectivity trends. The materials undergo significant transformations under CO2 reduction conditions, and their dynamic bulk and surface structures are revealed by correlating observations from multiple methods—X-ray absorption spectroscopy for in situ study, and quasi in situ X-ray photoelectron spectroscopy for surface sensitivity. For both types of catalysts, Cu transforms to metallic Cu0 under reaction conditions. However, the Sn speciation and content differ significantly between the catalyst types: the CO-selective catalysts exhibit a surface Sn content of 13 at. % predominantly present as oxidized Sn, while the formate-selective catalysts display an Sn content of ≈70 at. % consisting of both metallic Sn0 and Sn oxide species. Density functional theory simulations suggest that Snδ+ sites weaken CO adsorption, thereby enhancing CO selectivity, while Sn0 sites hinder H adsorption and promote formate production. This study reveals the complex dependence of catalyst structure, composition, and speciation with electrochemical bias in bimetallic Cu catalysts.
KW - Electrochemical CO2 conversion
KW - Cu catalysts
KW - X-ray absorption spectroscopy
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-547116
DO - https://doi.org/10.1002/aenm.202103328
SN - 1614-6832
VL - 12
IS - 5
SP - 2103328
PB - Wiley-VCH GmbH
AN - OPUS4-54711
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bornemann-Pfeiffer, Martin
A1 - Wolf, Jakob
A1 - Meyer, Klas
A1 - Kern, S.
A1 - Angelone, D.
A1 - Leonov, A.
A1 - Cronin, L.
A1 - Emmerling, Franziska
T1 - Standardization and control of Grignard reactions in a universal chemical synthesis machine using online NMR
T1 - Standardisierung und Kontrolle von Grignard-Reaktionen mittels Online-NMR in einer universellen chemischen Syntheseplattform
N2 - A big problem with the chemistry literature is that it is not standardized with respect to precise operational parameters, and real time corrections are hard to make without expert knowledge. This lack of context means difficult reproducibility because many steps are ambiguous, and hence depend on tacit knowledge. Here we present the integration of online NMR into an automated chemical synthesis machine (CSM aka. “Chemputer” which is capable of small-molecule synthesis using a universal programming language) to allow automated analysis and adjustment of reactions on the fly. The system was validated and benchmarked by using Grignard reactions which were chosen due to their importance in synthesis. The system was monitored in real time using online-NMR, and spectra were measured continuously during the reactions. This shows that the synthesis being done in the Chemputer can be dynamically controlled in response to feedback optimizing the reaction conditions according to the user requirements.
N2 - Ein Problem der chemischen Literatur ist die fehlende Standardisierung bezüglich genauer Bedingungen, auch Echtzeit-Korrekturen sind ohne Expertenwissen nur schwer möglich. Dieser Mangel an Details erschwert experimentelle Reproduzierbarkeit, da Schritte oft mehrdeutig sind und daher von implizitem Wissen abhängen. Hier präsentieren wir die Integration von Online-NMR Spektroskopie in eine automatisierte chemische Syntheseplattform (CSM aka. “Chemputer”, unter Verwendung einer universellen Programmiersprache zur Synthese kleiner Moleküle fähig), um eine automatisierte Analyse und Anpassung von Reaktionen im laufenden Betrieb zu ermöglichen. Das System wurde anhand von Grignard-Reaktionen, die aufgrund ihrer Bedeutung für die Synthese ausgewählt wurden, validiert und einem Härtetest unterzogen. Synthesen wurden in Echtzeit mit Online-NMR überwacht, und die Spektren wurden während der Reaktionen kontinuierlich aufgenommen und analysiert. Dies zeigt, dass der Chemputer dynamisch mittels einer Regelung kontrolliert werden kann, um die Reaktionsbedingungen entsprechend den Anforderungen des Benutzers zu optimieren.
KW - Grignard reaction
KW - NMR spectroscopy
KW - Process analytical technology
KW - Process control
KW - Grignard-Reaktion
KW - NMR-Spektroskopie
KW - Prozessanalytik
KW - Prozesskontrolle
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-531260
DO - https://doi.org/10.1002/anie.202106323
SN - 1521-3773
SN - 1433-7851
N1 - Bibliografische Angaben für die deutsche Version: Angewandte Chemie 2021, Jg. 133, S. 1–7, ISSN 0044-8249, ISSN 1521-3757, https://doi.org/10.1002/ange.202106323 - Bibliographic information for the German version: Angewandte Chemie 2021, vol. 133, p. 1–7, ISSN 0044-8249, ISSN 1521-3757, https://doi.org/10.1002/ange.202106323
VL - 60
IS - 43
SP - 1
EP - 6
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-53126
LA - mul
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Steglich, P.
A1 - Bondarenko, S.
A1 - Mai, C.
A1 - Paul, Martin
A1 - Weller, Michael G.
A1 - Mai, A.
T1 - CMOS-Compatible Silicon Photonic Sensor for Refractive Index Sensing Using Local Back-Side Release
N2 - Silicon photonic sensors are promising candidates for lab-on-a-chip solutions with versatile applications and scalable production prospects using complementary metal-oxide semiconductor (CMOS) fabrication methods. However, the widespread use has been hindered because the sensing area adjoins optical and electrical components making packaging and sensor handling challenging. In this work, a local back-side release of the photonic sensor is employed, enabling a separation of the sensing area from the rest of the chip. This approach allows preserving the compatibility of photonic integrated circuits in the front-end of line and metal interconnects in the back-end of line. The sensor is based on a micro-ring resonator and is fabricated on wafer-level using a CMOS technology. We revealed a ring resonator sensitivity for homogeneous sensing of 106 nm/RIU.
KW - Photonic biosensor
KW - Lab-on-a-chip
KW - Ring resonator
KW - Resonance wavelength shift
KW - PIC technology
KW - Back-side integration
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-517139
DO - https://doi.org/10.1109/LPT.2020.3019114
VL - 32
IS - 19
SP - 1241
EP - 1244
PB - IEEE
AN - OPUS4-51713
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Steglich, Patrick
A1 - Paul, Martin
A1 - Mai, C.
A1 - Böhme, A.
A1 - Bondarenko, S.
A1 - Weller, Michael G.
A1 - Mai, A.
T1 - A monolithically integrated microfluidic channel in a silicon-based photonic-integrated-circuit technology for biochemical sensing
N2 - In this work, a cost-effective optofluidic system is proposed and preliminary experimental results are presented. A microfluidic channel monolithically integrated into a photonic integrated circuit technology is used in conjunction with a cyclic olefin copolymer (COC) substrate to provide fluidic in- and output ports. We report on initial experimental results as well as on the simple and cost-effective fabrication of this optofluidic system by means of micro-milling.
KW - Biosensors
KW - Biophotonics
KW - Optical sensors
KW - Photonic sensors
KW - Ring resonators
KW - Silicon photonics
KW - Lab-on-a-chip
KW - Microfluidics
KW - Chip
KW - Biochip
PY - 2021
DO - https://doi.org/10.1117/12.2588791
VL - 11772
SP - 1
EP - 5
PB - SPIE
AN - OPUS4-53559
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dittmar, Stefan
A1 - Weyrauch, Steffen
A1 - Reemtsma, Thorsten
A1 - Eisentraut, Paul
A1 - Altmann, Korinna
A1 - Ruhl, Aki S.
A1 - Jekel, Martin
T1 - Settling Velocities of Tire and Road Wear Particles: Analyzing Finely Graded Density Fractions of Samples from a Road Simulator and a Highway Tunnel
N2 - The terminal settling velocity is considered the most critical parameter determining the transport of tire and road wear particles (TRWP) in aquatic environments. Nonetheless, no respective empirical data has been reported so far. In this study, particle samples from a road simulator and a highway tunnel were investigated with a validated imaging method. Different density and size fractions of both samples were measured separately, acquiring sizes and settling velocities of more than 30,000 individual particles. In addition, tire marker polymers were analyzed for each fraction via thermal extraction desorption-gas chromatography/mass spectrometry. Finally, the acquired particle data was combined according to the fractions’ estimated tire contents in order to deduce detailed probability distributions of particle size and settling velocity for the actual TRWP from both samples. Weighted by TRWP-incorporated tire mass, median diameters of 54 and 44 μm as well as median settling velocities of 0.65 and 0.22 mm/s were found for TRWP from the road simulator and highway tunnel, respectively. This study thus provides the first ever empirical data on TRWP settling velocities in water, which can be highly valuable input for modeling the environmental transport of TRWP and for dimensioning TRWP retention systems.
KW - Microplastics
KW - TED-GC/MS
KW - Sinking velocities
KW - Transport
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-635449
DO - https://doi.org/10.1021/acs.est.5c04165
SN - 0013-936X
VL - 59
IS - 26
SP - 13434
EP - 13446
PB - American Chemical Society (ACS)
AN - OPUS4-63544
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dittmar, Stefan
A1 - Ruhl, Aki S.
A1 - Altmann, Korinna
A1 - Jekel, Martin
T1 - Settling Velocities of Small Microplastic Fragments and Fibers
N2 - There is only sparse empirical data on the settling velocity of small, non-buoyant microplastics thus far, although it is an important parameter governing their vertical transport within aquatic environments. This study reports the settling velocities of 4031 exemplary microplastic particles. Focusing on the environmentally most prevalent particle shapes, irregular microplastic fragments of four different polymer types (9–289 µm) as well as five discrete length fractions (50–600 µm) of common nylon and polyester fibers were investigated, respectively. All settling experiments were carried out in quiescent water using a specialized optical imaging setup. The method has been previously validated in order to minimize disruptive factors, e.g. thermal convection or particle interactions, and thus enable the precise measurements of the velocities of individual microplastic particles (0.003–9.094 mm/s). Based on the obtained data, ten existing models for predicting a particle’s terminal settling velocity were assessed. It is concluded that models, which were specifically deduced from empirical data on larger microplastics, fail to provide accurate predictions for small microplastics. Instead, a different approach is highlighted as a viable option for computing settling velocities across the microplastics continuum in terms of size, density and shape.
KW - Microplastics
KW - Microplastic fibers
KW - Settling velocity
KW - Sinking velocity
KW - Sedimentation
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597455
DO - https://doi.org/10.1021/acs.est.3c09602
SN - 0013-936X
VL - 58
IS - 14
SP - 6359
EP - 6369
PB - American Chemical Society (ACS)
AN - OPUS4-59745
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kulow, Anicó
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Reinholz, Uwe
A1 - Emmerling, Franziska
A1 - Hampel, S.
A1 - Fittschen, U.E.A.
A1 - Streli, C.
A1 - Radtke, Martin
T1 - Comparison of three reconstruction methods based on deconvolution, iterative algorithm and neural network for X-ray fluorescence imaging with coded apertures
N2 - X-ray imaging methods are used in many fields of research, as they allow a non-destructive Investigation of the elemental content of various samples. As for every imaging method, for X-ray imaging the optics are of crucial importance. However, these optics can be very expensive and laborious to build, as the requirements on surface roughness and precision are extremely high. Angles of reflection and refraction are often in the range of a few mrad, making a compact design hard to achieve. In this work we present a possibility to simplify X-ray imaging. We have adapted the coded aperture method, a high energy radiation imaging method that has its origins in astrophysics, to full field X-ray fluorescence imaging. In coded aperture imaging, an object is projected through a known mask, the coded aperture, onto an area sensitive detector. The resulting image consists of overlapping projections of the object and a reconstruction step is necessary to obtain the information from the recorded image. We recorded fluorescence images of different samples with an energy-dispersive 2D detector (pnCCD) and investigated different reconstruction methods. With a small coded aperture with 12 holes we could significantly increase the count rate compared to measurements with a straight polycapillary optic. We show that the reconstruction of two different samples is possible with a deconvolution approach, an iterative algorithm and a neural network. These results demonstrate that X-ray fluorescence imaging with coded apertures has the potential to deliver good results without scanning and with an improved count rate, so that measurement times can be shortened compared to established methods.
KW - X-ray fluorescence imaging
KW - Coded apertures
KW - Imaging
KW - Elemental mapping
KW - Image reconstruction
PY - 2020
DO - https://doi.org/10.1039/d0ja00146e
VL - 35
IS - 7
SP - 1423
EP - 1434
PB - Royal Society of Chemistry
CY - United Kingdom
AN - OPUS4-51518
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kulow, Anicó
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Reinholz, Uwe
A1 - Emmerling, Franziska
A1 - Hampel, S.
A1 - Fittschen, UEA
A1 - Streli, C.
A1 - Radtke, Martin
T1 - Reconstruction for coded aperture full-field x-ray fluorescence imaging
N2 - X-ray fluorescence imaging is a well-established tool in materials characterization. In this work, we present the adaption of coded aperture imaging to full-field X-ray fluorescence imaging at the synchrotron. Coded aperture imaging has its origins in astrophysics, and has several advantages: Coded apertures are relatively easy to fabricate, achromatic, allow a high photon throughput, and high angular acceptance. Coded aperture imaging is a two-step-process, consisting of the measurement process and a reconstruction step. Different programs have been written, for the raytracing/forward projection and the reconstruction. Experiments with coded aperture in combination with a Color X-ray Camera and an energy-dispersive area detector, have been conducted at the BAMline. Measured samples were successfully reconstructed, and gave a 9.1-fold increase in count rate compared to a polycapillary optic.
KW - Synchrotron
KW - BAMline
KW - Coded Aperture
PY - 2022
SN - 1097-0002
VL - 65
SP - 57
EP - 70
PB - Cambridge University Press
CY - Cambridge
AN - OPUS4-56350
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Berger, J.
A1 - Zahedi-Azad, S.
A1 - Voss, H.
A1 - Ernst, O.C.
A1 - Hammerschmidt, R.
A1 - Boeck, T.
A1 - Martin, J.
A1 - Bonse, J.
A1 - Krüger, J.
A1 - Schmid, M.
T1 - CuInSe2-based micro-concentrator solar cells fabricated from In islands grown by laser-assisted MO-CVD
N2 - Micro-concentrator solar cells offer a promising route for reducing material usage in photovoltaics. For Cu(In,Ga)Se2, multiple micro-concentrator manufacturing methods have already been evaluated. All of them involve either high preparation complexity or post-processing to recycle unused precursor or absorber materials. In this work, a new method using laser-assisted metal-organic chemical vapor deposition (LA-MOCVD) was applied to directly grow arrays of indium micro-islands. These arrays are examined and further processed to CuInSe2 micro-solar cell arrays. The geometry and morphology of the islands were investigated and compared before and after absorber formation. The investigation shows that the absorber growth is limited to the vertical direction normal to the substrate surface and that the starting morphology is preserved. Furthermore, the absorber island arrays are processed into micro-modules and operational solar cells are achieved as a proof of principle. These not yet optimized arrays reach a conversion efficiency of 0.65% under 1 sun illumination. Under 17 suns of light concentration, the efficiency gain is between 60 and 250%. This work demonstrates the method's viability for the fabrication of micro-solar cell arrays, with clear potential for achieving higher conversion efficiencies through future optimization.
KW - Micro-concentrator solar cells
KW - Laser-assisted chemical vapor deposition
KW - CISe
KW - Bottom-up fabrication
KW - Resource efficiency
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656711
DO - https://doi.org/10.1016/j.solmat.2026.114284
SN - 0927-0248
VL - 301
SP - 1
EP - 10
PB - Elsevier B.V.
AN - OPUS4-65671
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kim, Y.S.
A1 - Li, Y.-C.
A1 - Pitts, W.M.
A1 - Werrel, Martin
A1 - Davis, R.D.
T1 - Rapid growing clay coatings to reduce the fire threat of furniture
N2 - Layer-by-layer (LbL) assembly coatings reduce the flammability of textiles and polyurethane foam but require extensive repetitive processing steps to produce the desired coating thickness and nanoparticle fire retardant content that translates into a fire retardant coating. Reported here is a new hybrid bi-layer (BL) approach to fabricate fire retardant coatings on polyurethane foam. Utilizing hydrogen bonding and electrostatic attraction along with the pH adjustment, a fast growing coating with significant fire retardant clay content was achieved. This hybrid BL coating exhibits significant fire performance improvement in both bench scale and real scale tests. Cone calorimetry bench scale tests show a 42% and 71% reduction in peak and average heat release rates, respectively. Real scale furniture mockups constructed using the hybrid LbL coating reduced the peak and average heat release rates by 53% and 63%, respectively. This is the first time that the fire safety in a real scale test has been reported for any LbL technology. This hybrid LbL coating is the fastest approach to develop an effective fire retardant coating for polyurethane foam.
KW - Layer-by-layer assembly
KW - Polyurethane foam
KW - Sodium montmorillonite
KW - Flame retardant
KW - Real scale mockup
PY - 2014
DO - https://doi.org/10.1021/am405259n
SN - 1944-8244
SN - 0013-936X
SN - 1944-8252
VL - 6
IS - 3
SP - 2146
EP - 2152
PB - ACS Publ.
CY - Washington, DC, USA
AN - OPUS4-31489
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Gardei, André
A1 - Garcia, O.
A1 - Riedl, Martin
A1 - Vanhellemond, I.
A1 - Suput, J.S.
A1 - Santarelli, M.-L.
A1 - Rodríguez-Maribona, I.
A1 - Müller, Urs
ED - Jadwiga W. Lukaszewicz,
ED - Piotr Niemcewicz,
T1 - Performance and durability of a new antigraffiti system for cultural heritage - the EC project GRAFFITAGE
T2 - 11th International Congress on Deterioration and Conservation of Stone
CY - Torun, Poland
DA - 2008-09-15
KW - Cultural heritage
KW - Antigraffiti system
KW - Sandstone
KW - Limestone
KW - Brick
KW - Monument
KW - Cleaning
KW - Historische Baustoffe
PY - 2008
SN - 978-83-231-2237-1
VL - II
SP - 889
EP - 897
PB - Nicolaus Copernicus University Press
CY - Torun, Poland
AN - OPUS4-18844
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -