TY - JOUR A1 - Kim, K. J. A1 - Kim, A. S. A1 - Jang, J. S. A1 - Suh, J. K. A1 - Wirth, Thomas A1 - Hodoroaba, Vasile-Dan A1 - Unger, Wolfgang A1 - Araujo, J. R. A1 - Archanjo, B. S. A1 - Galhardo, C. E. A1 - Damasceno, J. A1 - Achete, C. A. A1 - Wang, H. A1 - Wang, M. A1 - Bennett, J. A1 - Simons, D. A1 - Kurokawa, A. A1 - Terauchi, S. A1 - Fujimoto, T. A1 - Streeck, C. A1 - Beckhoff, B. A1 - Spencer, S. A1 - Shard, A. T1 - Measurement of mole fractions of Cu, In, Ga and Se in Cu(In,Ga)Se2 films N2 - CCQM key comparison K-129 for the quantitative analysis of Cu(In,Ga)Se2 (CIGS) films has been performed by the Surface Analysis Working Group (SAWG) of the Consultative Committee for Amount of Substance (CCQM). The objective of this key comparison is to compare the equivalency of the National Metrology Institutes (NMIs) and Designated Institutes (DIs) for the measurement of mole fractions of Cu, In, Ga and Se in a thin CIGS film. The measurand of this key comparison is the average mole fractions of Cu, In, Ga and Se of a test CIGS alloy film in the unit of mole fraction (mol/mol). Mole fraction with the metrological unit of mol/mol can be practically converted to atomic fraction with the unit of at%. In this key comparison, a CIGS film with certified mole fractions was supplied as a reference specimen to determine the relative sensitivity factors (RSFs) of Cu, In, Ga and Se. The mole fractions of the reference specimen were certified by isotope dilution - inductively coupled plasma/mass spectrometry (ID-ICP/MS) and are traceable to the SI. A total number counting (TNC) method was recommended as a method to determine the signal intensities of the constituent elements acquired in the depth profiles by Secondary Ion Mass Spectrometry (SIMS), X-ray Photoelectron Spectroscopy (XPS) and Auger Electron Spectroscopy (AES). Seven NMIs and one DI participated in this key comparison. The mole fractions of the CIGS films were measured by depth profiling based-SIMS, AES and XPS. The mole fractions were also measured by non-destructive X-Ray Fluorescence (XRF) Analysis and Electron Probe Micro Analysis (EPMA) with Energy Dispersive X-ray Spectrometry (EDX). In this key comparison, the average degrees of equivalence uncertainties for Cu, In, Ga and Se are 0.0093 mol/mol, 0.0123 mol/mol, 0.0047 mol/mol and 0.0228 mol/mol, respectively. These values are much smaller than that of Fe in a Fe-Ni alloy film in CCQM K-67 (0.0330 mol/mol). This means that the quantification of multi-element alloy films is possible by depth profiling analysis using the TNC method. KW - CIGS KW - Key comparison KW - CCQM KW - SIMS KW - XPS KW - AES KW - XRF KW - EPMA PY - 2016 UR - http://iopscience.iop.org/article/10.1088/0026-1394/53/1A/08011 DO - https://doi.org/10.1088/0026-1394/53/1A/08011 SN - 0026-1394 SN - 1681-7575 VL - 53, Technical Supplement SP - Article 08011, 1 EP - 19 PB - IOP Publishing AN - OPUS4-38110 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Heinrich, Thomas A1 - Traulsen, Christoph Hans-Henning A1 - Holzweber, Markus A1 - Richter, S. A1 - Kunz, V. A1 - Kastner, S.K. A1 - Krabbenborg, S.O. A1 - Huskens, J. A1 - Unger, Wolfgang A1 - Schalley, C.A. T1 - Coupled molecular switching processes in ordered mono- and multilayers of stimulus-responsive rotaxanes on gold surfaces N2 - Interfaces provide the structural basis for function as, for example, encountered in nature in the membrane-embedded photosystem or in technology in solar cells. Synthetic functional multilayers of molecules cooperating in a coupled manner can be fabricated on surfaces through layer-by-layer self-assembly. Ordered arrays of stimulus-responsive rotaxanes undergoing well-controlled axle shuttling are excellent candidates for coupled mechanical motion. Such stimulus-responsive surfaces may help integrate synthetic molecular machines in larger systems exhibiting even macroscopic effects or generating mechanical work from chemical energy through cooperative action. The present work demonstrates the successful deposition of ordered mono- and multilayers of chemically switchable rotaxanes on gold surfaces. Rotaxane mono- and multilayers are shown to reversibly switch in a coupled manner between two ordered states as revealed by linear dichroism effects in angle-resolved NEXAFS spectra. Such a concerted switching process is observed only when the surfaces are well packed, while less densely packed surfaces lacking lateral order do not exhibit such effects. KW - Molecular machine KW - Rotaxane KW - LBL growth KW - XPS KW - NEXAFS KW - SIMS PY - 2015 DO - https://doi.org/10.1021/ja512654d SN - 0002-7863 SN - 1520-5126 VL - 137 IS - 13 SP - 4382 EP - 4390 PB - American Chemical Society CY - Washington, DC, USA AN - OPUS4-33077 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Traulsen, C. H.-H. A1 - Kunz, V. A1 - Heinrich, Thomas A1 - Richter, S. A1 - Holzweber, Markus A1 - Schulz, A. A1 - von Krbek, L. K. S. A1 - Scheuschner, U. T. J. A1 - Poppenberg, J. A1 - Unger, Wolfgang A1 - Schalley, C. A. T1 - Synthesis and coordinative layer-by-layer deposition of pyridine-functionalized gold nanoparticles and tetralactam macrocycles on silicon substrates N2 - Coordination chemistry was applied to deposit pyridine-functionalized gold nanoparticles on silicon substrates. The particles were synthesized through the Brust/Schiffrin route with a subsequent ligand exchange reaction yielding well-defined particles of two different sizes. Multilayer deposition was carried out on a pyridine-terminated SAM, anchored on a hydroxyl-terminated silicon surface. Analogously, Hunter/Vögtle-type tetralactam macrocycle multilayers were deposited as well as mixed layers containing both either in an alternating sequence or as a macrocycle multilayer with a terminating nanoparticle layer. These composite layers were examined with respect to their ability to bind squaraine axles in the macrocycle cavities. The amount of guest bound is higher for the composite layer with alternating macrocycles and nanoparticles. KW - Layer-by-layer deposition KW - Functionalized Au nanoparticles KW - SEM KW - TEM KW - DLS KW - XPS KW - NEXAFS KW - ToF-SIMS KW - IR KW - UV-vis PY - 2013 DO - https://doi.org/10.1021/la403222x SN - 0743-7463 SN - 1520-5827 VL - 29 IS - 46 SP - 14284 EP - 14292 PB - American Chemical Society CY - Washington, DC AN - OPUS4-29699 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sattari, S. A1 - Beyranvand, S. A1 - Soleimani, K. A1 - Rassoli, K. A1 - Salahi, P. A1 - Donskyi, Ievgen A1 - Shams, A. A1 - Unger, Wolfgang A1 - Yari, A. A1 - Farjanikish, G. A1 - Nayebzadeh, H. A1 - Adeli, M. T1 - Boronic Acid-Functionalized Two-Dimensional MoS2 at Biointerfaces N2 - While noncovalent interactions at two-dimensional nanobiointerfaces are extensively investigated, less knowledge about covalent interactions at this interface is available. In this work, boronic acid-functionalized 2D MoS2 was synthesized and its covalent multivalent interactions with bacteria and nematodes were investigated. Polymerization of glycidol by freshly exfoliated MoS2 and condensation of 2,5-thiophenediylbisboronic acid on the produced platform resulted in boronic acid-functionalized 2D MoS2. The destructive interactions between 2D MoS2 and bacteria as well as nematodes were significantly amplified by boronic acid functional groups. Because of the high antibacterial and antinematodal activities of boronic acid-functionalized 2D MoS2, its therapeutic efficacy for diabetic wound healing was investigated. The infected diabetic wounds were completely healed 10 days after treatment with boronic acid-functionalized 2D MoS2, and a normal structure for recovered tissues including different layers of skin, collagen, and blood vessels was detected. KW - XPS KW - Boronic acid-functionalized 2D MoS2 KW - Covalent interactions KW - Bacteria KW - Nanobiointerfaces PY - 2020 DO - https://doi.org/10.1021/acs.langmuir.0c00776 VL - 36 IS - 24 SP - 6706 EP - 6715 PB - ACS American Chemical Society AN - OPUS4-51024 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Beyranvand, S. A1 - Pourghobadi, Z. A1 - Sattari, S. A1 - Soleymani, K. A1 - Donskyi, Ievgen A1 - Gharabaghi, M. A1 - Unger, Wolfgang A1 - Farjanikish, G. A1 - Nayebzadeh, H. A1 - Adeli, M. T1 - Boronic acid functionalized graphene platforms for diabetic wound N2 - While noncovalent interactions between graphene derivatives and biosystems are extensively studied, less knowledge about their covalent multivalent interactions at biointerfaces is available. Due to the affinity of boronic acids towards cis-diol bearing biosystems, graphene sheets with this functionality were synthesized and their covalent interactions with the bacteria and nematode were investigated. As expected, graphene platforms with boronic acid functionality were able to wrap bacteria and destroy it in a short time. Surprisingly, body of nematodes was ruptured and their viability decreased to 30% after 24 h incubation with the functionalized graphene sheets. Because of their antibacterial and antiparasitic activities as well as their ability for wound dressing, graphene platforms with the boronic acid functionality were further investigated for diabetic wound healing. In vivo experiments showed that graphene platforms are more efficient than the commercially available drug, phenytoin, and restore both infected and non-infected diabetic wounds in ten days. Taking advantage of their straightforward synthesis, strong interactions with different biosystems as well as their ability to heal diabetic wounds, the boronic Acid functionalized graphene sheets are promising candidates for a broad range of future biomedical applications. KW - Graphene KW - Boronic acid KW - Functionalized graphene KW - XPS PY - 2020 UR - https://www.sciencedirect.com/science/article/abs/pii/S0008622319310954 DO - https://doi.org/doi.org/10.1016/j.carbon.2019.10.077 VL - 158 SP - 327 EP - 336 PB - Elsevier Ltd. AN - OPUS4-50559 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Faghani, A. A1 - Gholami, M. F. A1 - Trunk, M. A1 - Müller, J. A1 - Pachfule, P. A1 - Vogl, S. A1 - Donskyi, Ievgen A1 - Li, M. A1 - Nickl, Philip A1 - Shao, J. A1 - Huang, M. R. S. A1 - Unger, Wolfgang A1 - Arenal, R. A1 - Koch, C. T. A1 - Paulus, B. A1 - Rabe, J. P. A1 - Thomas, A. A1 - Haag, R. A1 - Adeli, M. T1 - Metal-Assisted and Solvent-Mediated Synthesis of Two-Dimensional Triazine Structures on Gram Scale N2 - Covalent triazine frameworks are an emerging material class that have shown promising performance for a range of applications. In this work, we report on a metal-assisted and solvent-mediated reaction between calcium carbide and cyanuric chloride, as cheap and commercially available precursors, to synthesize two-dimensional triazine structures (2DTSs). The reaction between the solvent, dimethylformamide, and cyanuric chloride was promoted by calcium carbide and resulted in dimethylamino-s-triazine intermediates, which in turn undergo nucleophilic substitutions. This reaction was directed into two dimensions by calcium ions derived from calcium carbide and induced the formation of 2DTSs. The role of calcium ions to direct the two-dimensionality of the final structure was simulated using DFT and further proven by synthesizing molecular intermediates. The water content of the reaction medium was found to be a crucial factor that affected the structure of the products dramatically. While 2DTSs were obtained under anhydrous conditions, a mixture of graphitic material/2DTSs or only graphitic material (GM) was obtained in aqueous solutions. Due to the straightforward and gram-scale synthesis of 2DTSs, as well as their photothermal and photodynamic properties, they are promising materials for a wide range of future applications, including bacteria and virus incapacitation. KW - XPS KW - Triazine KW - 2D PY - 2020 DO - https://doi.org/10.1021/jacs.0c02399 VL - 142 IS - 30 SP - 12976 EP - 12986 PB - ACS American Chemical Society AN - OPUS4-51203 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Müller, Anja A1 - Heinrich, Thomas A1 - Tougaard, S. A1 - Werner, W. S. M. A1 - Hronek, M. A1 - Kunz, Valentin A1 - Radnik, Jörg A1 - Stockmann, Jörg M. A1 - Hodoroaba, Vasile-Dan A1 - Benemann, Sigrid A1 - Nirmalananthan-Budau, Nithiya A1 - Geißler, Daniel A1 - Sparnacci, K. A1 - Unger, Wolfgang T1 - Determining the thickness and completeness of the shell of polymer core-shell nanoparticles by X-ray photoelectron spectroscopy, secondary ion mass spectrometry, and transmission scanning electron microscopy N2 - Core–shell nanoparticles (CSNPs) have become indispensable in various industrial applications. However, their real internal structure usually deviates from an ideal core–shell structure. To control how the particles perform with regard to their specific applications, characterization techniques are required that can distinguish an ideal from a nonideal morphology. In this work, we investigated poly(tetrafluoroethylene)–poly(methyl methacrylate) (PTFE–PMMA) and poly(tetrafluoroethylene)–polystyrene (PTFE–PS) polymer CSNPs with a constant core diameter (45 nm) but varying shell thicknesses (4–50 nm). As confirmed by transmission scanning electron microscopy (T-SEM), the shell completely covers the core for the PTFE–PMMA nanoparticles, while the encapsulation of the core by the shell material is incomplete for the PTFE–PS nanoparticles. X-ray photoelectron spectroscopy (XPS) was applied to determine the shell thickness of the nanoparticles. The software SESSA v2.0 was used to analyze the intensities of the elastic peaks, and the QUASES software package was employed to evaluate the shape of the inelastic background in the XPS survey spectra. For the first time, nanoparticle shell thicknesses are presented, which are exclusively based on the analysis of the XPS inelastic background. Furthermore, principal component analysis (PCA)-assisted time-of-flight secondary-ion mass spectrometry (ToF-SIMS) of the PTFE–PS nanoparticle sample set revealed a systematic variation among the samples and, thus, confirmed the incomplete encapsulation of the core by the shell material. As opposed to that, no variation is observed in the PCA score plots of the PTFE–PMMA nanoparticle sample set. Consequently, the complete coverage of the core by the shell material is proved by ToF-SIMS with a certainty that cannot be achieved by XPS and T-SEM. KW - XPS KW - T-SEM KW - ToF-SIMS KW - Core-shell nanoparticles PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-499165 DO - https://doi.org/10.1021/acs.jpcc.9b09258 VL - 123 IS - 49 SP - 29765 EP - 29775 PB - American Chemical Society CY - Washington, DC AN - OPUS4-49916 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Unger, Wolfgang A1 - Senoner, Mathias A1 - Wirth, Thomas A1 - Bütefisch, S. A1 - Busch, I. T1 - Lateral resolution delivered by imaging surface-analytical instruments as SIMS, AES and XPS: Application of the BAM-L200 Certified Reference Material and related ISO Standards N2 - The certified reference material BAM-L200, a nanoscale stripe pattern for length calibration and specification of lateral resolution, is described. BAM-L200 is prepared from a cross-sectioned epitaxially grown layer stack of AlxGa1-xAs and InxGa1 xAs on a GaAs substrate. The surface of BAM-L200 provides a flat pattern with stripe widths ranging down to 1 nm. Calibration distances, grating periods and stripe widths have been certified by TEM with traceability to the length unit. The combination of gratings, isolated narrow stripes and sharp edges of wide stripes offers a plenty of options for the determination of lateral resolution, sharpness and calibration of length scale at selected settings of imaging surface analytical instruments. The feasibility of the reference material for an analysis of the lateral resolution is demonstrated in detail by evaluation of ToF-SIMS, AES and EDX images. Other applications developed in the community are summarized, too. BAM-L200 fully supports the implementation of the revised International Standard ISO 18516 (in preparation) which is based on knowledge outlined in the Technical Report ISO/TR 19319:2013. KW - Standardization KW - AES KW - XPS KW - SIMS KW - Lateral resolution KW - Certified reference material PY - 2017 SN - 1341-1756 VL - 24 IS - 2 SP - 123 EP - 128 AN - OPUS4-43138 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Poppenberg, J. A1 - Richter, S. A1 - Traulsen, Ch. H.-H. A1 - Darlatt, Erik A1 - Baytekin, B. A1 - Heinrich, Thomas A1 - Deutinger, P. M. A1 - Huth, K. A1 - Unger, Wolfgang A1 - Schalley, Ch. T1 - Programmable multilayers of nanometer-sized macrocycles on solid support and stimuli-controlled on-surface pseudorotaxane formation N2 - Mechanically interlocked molecules (MIMs) such as rotaxanes and catenanes are capable of mechanical motion on the nanoscale and are therefore promising prototypes for molecular machines in recent nanotechnology. However, most of the existing examples are isotropically distributed in solution, which prohibits concerted movement and with it the generation of macroscopic effects. Thus, arranging them in ordered arrays is of huge interest in recent research. We report the deposition of quite densely packed multilayers of tetralactam macrocycles on gold surfaces by metal-coordinated layer-by-layer self-assembly. Linear dichroism effects in angle-resolved NEXAFS spectra indicate a preferential orientation of the macrocycles. The sequence of the metal ions can be programmed by the use of different transition metal ions at each deposition step. Additionally, reversible on-surface pseudorotaxane formation was successfully realized by repeated uptake and release of axle molecules inside the macrocycles cavities. KW - NEXAFS KW - XPS KW - Supramolecular Chemistry KW - Multilayers KW - Pyridine KW - UV/Vis KW - Macrocycles KW - Pseudorotaxanes PY - 2013 DO - https://doi.org/10.1039/c3sc50558h VL - 4 IS - 8 SP - 3131 EP - 3139 AN - OPUS4-42668 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Richter, S. A1 - Traulsen, C. H.-H. A1 - Heinrich, Thomas A1 - Poppenberg, J. A1 - Leppich, C. A1 - Holzweber, Markus A1 - Unger, Wolfgang A1 - Schalley, C.A. T1 - Sequence-programmable multicomponent multilayers of nanometer-sized tetralactam macrocycles on gold surfaces N2 - Multicomponent multilayers have been deposited on gold surfaces by metal-ion-mediated layer-by-layer self-assembly of differently functionalized tetralactam macrocycles. The layer stack can be programmed with respect to the sequences of metal ions and macrocycles by the deposition sequence. KW - Organic layer KW - XPS KW - SIMS KW - NEXAFS PY - 2013 DO - https://doi.org/10.1021/jp405492v SN - 1932-7447 SN - 1089-5639 VL - 117 IS - 37 SP - 18980 EP - 18985 PB - Soc. CY - Washington, DC AN - OPUS4-32576 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 - Krakert, S. A1 - Schüpbach, B. A1 - Terfort, A. A1 - Unger, Wolfgang T1 - Amine species on self-assembled monolayers of omega-aminothiolates on gold as identified by XPS and NEXAFS spectroscopy N2 - Functionalised surfaces are of interest in many fields, e.g. in biomedicine, materials science and molecular electronics. In this study a series of self-assembled aliphatic and aromatic monolayers on gold substrates with terminal amino groups was investigated. Four different thiol molecules were used: aliphatic 11-aminoundecane-1-thiol (AUDT), aromatic 4-aminobenzenethiol (ABT) and aromatic ω-amino thiols with an alkyl spacer as 4-aminophenylbutane-1-thiol (APBT) and 3-(4''-amino-1,1':4',1''-terphenyl-4-yl)propane-1-thiol (ATPT). Evaluation of N 1s XPS data revealed that on the aromatic self-assembled monolayers (SAMs) amino groups exist preferentially as primary amines, whereas on the aliphatic SAM protonated and/or hydrogen-bonded amines are the major species. This result is crosschecked by N K edge near edge X-ray absorption fine structure (NEXAFS) spectroscopy and can be rationalised by the different basicity of aliphatic and aromatic amines. KW - Self-assembled monolayer KW - Amines KW - XPS KW - NEXAFS KW - Surface analysis PY - 2010 DO - https://doi.org/10.1002/sia.3224 SN - 0142-2421 SN - 1096-9918 VL - 42 SP - 1184 EP - 1187 PB - Wiley CY - Chichester AN - OPUS4-21498 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -