TY - CONF
A1 - Hertwig, Andreas
T1 - How can ellipsometry help us to understand ultrashort pulse laser material processing?
N2 - Laser processing of materials is a key technology in many fields of modern production. Still, more work is needed to understand the mechanisms behind laser material interaction. Recently, ellipsometry has become a valuable tool for investigating materials pre and post laser irradiation. Imaging ellipsometry and time-resolved methods boost this work and open up the path to a much better understanding of light interaction with solid state surfaces. We use spectroscopic single-spot and imaging ellipsometry to investigate treated and untreated surfaces. The goal is to determine changes in the material dielectric function, as well as geometric changes in surface layers (oxidation, modification, ablation, blistering). A good knowledge of bulk dielectric functions is often needed to model processes caused by laser irradiation. Imaging ellipsometry can play an important role in the post-analysis of laser treated sites on surfaces if combined with other methods such as IR-spectroscopy, SEM, topometric methods, Raman-spectroscopy, and XPS. In this work, we present the results of several studies to investigate laser-treated materials by means of ellipsometry. We cover the following topics:
• Ablation of amorphous carbon layers, role of intra-layer interference effects on the result
• Amorphisation behaviour of c-Si, depending on the crystal orientation,
• Understanding the role of bulk and surface properties on ablation behaviour of classical and
multicomponent high-entropy metals,
T2 - 13th Workshop on Spectroscopic Ellipsometry
CY - Genova, Italy
DA - 09.02.2026
KW - Ellipsometry
KW - Laser Ablation
KW - Femtosecond Technology
KW - Surface and Thin Layer Technology
KW - Laser Surface processing
PY - 2026
AN - OPUS4-65521
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - George, Janine
T1 - Robust Data Generation, Heuristics and Machine Learning for Materials Design
N2 - This talk first introduces students to the Materials Acceleration Platforms and Advanced Materials Characterization at BAM. Then, it motivates high-throuhgput screening for materials discovery and advanced materials simulations based on these core topics. Then four different research studies are presentend: evaluation of generative models, synthesizability prediction via PU learning, acceleration of materials property predictions with bonding analysis and advanced materials simulations supported by automatically trained machine learning potentials.
T2 - Guest Lecture in MSE 403/1003, a Seminar in the Curriculum of the University of Toronto
CY - Online meeting
DA - 13.02.2026
KW - Automation
KW - Materials Acceleration Platforms
KW - Machine Learning
KW - Workflows
KW - Phonons
KW - Bonding Analysis
KW - Thermal Conductivity
PY - 2026
AN - OPUS4-65514
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rastgou, Masoud
A1 - Hülagü, Deniz
A1 - Danilenko, Aleksandr
A1 - Manoocheri, Farshid
A1 - Hertwig, Andreas
A1 - Ikonen, Erkki
T1 - Comparison of thin-film thickness measurements using ellipsometry and reflectometry with uniform samples
N2 - This study evaluates spectroscopic ellipsometry and reflectometry using high-quality SiO2 and Al2O3 thin-films on Si substrates, thereby facilitating a detailed assessment of consistency of measurement results and uncertainty analyses. The results with detailed uncertainty budgets indicate good agreement between the two methods across a broad layer thickness range from 10 nm to 2000 nm, with deviations remaining well within the measurement uncertainties. Ellipsometry results have lower uncertainty than reflectometry results especially with the thinner layers, whereas reflectometry uncertainties are lower with the thickest layers studied. This work underscores the importance of rigorous thickness characterization and reliable uncertainty evaluation as critical factors in advancing both modeling and measurement practices in thin-film metrology.
KW - Ellipsometry
KW - Reflectometry
KW - Thin Film Metrology
KW - Measurement Accuracy
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655209
DO - https://doi.org/10.1088/1681-7575/ae3964
SN - 0026-1394
VL - 63
IS - 1
SP - 1
EP - 14
PB - IOP Publishing
CY - Bristol, UK
AN - OPUS4-65520
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Krause, Christina
A1 - Szymoniak, Paulina
A1 - Lohstroh, W.
A1 - Juranyi, F.
A1 - Zamponi, M.
A1 - Frick, B.
A1 - Al-Sabbagh, Dominik
A1 - Emmerling, Franziska
A1 - Zorn, R.
A1 - Schönhals, Andreas
T1 - Complex molecular dynamics of symmetric model discotic liquid crystals: Comparison of Hexakis(hepta-alkanoyloxy)triphenylene (HOT6) with Hexakis(hexa-alkyloxy)triphenylene (HAT6)
N2 - This study investigates the complex molecular dynamics of discotic liquid crystals (DLCs) by comparing two structurally similar compounds: Hexakis(hepta-alkanoyloxy)triphenylene (HOT6) and Hexakis(hexa-alkyloxy)triphenylene (HAT6) having the same triphenyl core and the same length of the alkyl side chain. The difference of both materials is that the alkyl chain is linked by an oxygen bridge to the triphenylene core for HAT6 and by a ester group for HOT6. Using a combination of broadband dielectric spectroscopy, differential scanning calorimetry, X-ray scattering, and neutron scattering techniques, the research explores the glass transition phenomena and relaxation processes in these materials. HOT6, featuring ester linkages, exhibits distinct dynamic behavior compared to HAT6, including two separate glass transitions indicated by the 1- and 2-relaxation found by dielectric spectroscopy which are assigned to the glassy dynamics of the alkyl side chain in the intercolumnar space and that of the columns, respectively. The study reveals that the ester group in HOT6 leads to increased molecular rigidity and altered packing in the intercolumnar space, as evidenced by X-ray scattering and the vibrational density of states. Neutron scattering confirms localized methyl group rotations and a further relaxation process which relates to the -relaxation revealed by dielectric spectroscopy. The findings contribute to a deeper understanding of glassy dynamics in partially ordered systems and highlight the influence of molecular architecture on relaxation behavior in DLCs.
KW - Discotic Liquid Crystals
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655171
DO - https://doi.org/10.1039/d5sm01247c
SP - 1
EP - 17
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-65517
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - INPR
A1 - Naik, Aakash A.
A1 - Dhamrait, Nidal
A1 - Ueltzen, Katharina
A1 - Ertural, Christina
A1 - Benner, Philipp
A1 - Rignanese, Gian-Marco
A1 - George, Janine
T1 - A critical assessment of bonding descriptors for predicting materials properties
N2 - Most machine learning models for materials science rely on descriptors based on materials compositions and structures, even though the chemical bond has been proven to be a valuable concept for predicting materials properties. Over the years, various theoretical frameworks have been developed to characterize bonding in solid-state materials. However, integrating bonding information from these frameworks into machine learning pipelines at scale has been limited by the lack of a systematically generated and validated database. Recent advances in high-throughput bonding analysis workflows have addressed this issue, and our previously computed Quantum-Chemical Bonding Database for Solid-State Materials was extended to include approximately 13,000 materials. This database is then used to derive a new set of quantum-chemical bonding descriptors. A systematic assessment is performed using statistical significance tests to evaluate how the inclusion of these descriptors influences the performance of machine-learning models that otherwise rely solely on structure- and composition-derived features. Models are built to predict elastic, vibrational, and thermodynamic properties typically associated with chemical bonding in materials. The results demonstrate that incorporating quantum-chemical bonding descriptors not only improves predictive performance but also helps identify intuitive expressions for
properties such as the projected force constant and lattice thermal conductivity via symbolic regression.
KW - Bonding Analysis
KW - Machine Learning
KW - Symbolic Regression
KW - Chemical Understanding
KW - Phonons
KW - Thermal Conductivity
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655150
DO - https://doi.org/10.48550/arXiv.2602.12109
SP - 1
EP - 28
PB - Cornell University
CY - Ithaca, NY
AN - OPUS4-65515
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gerrits, Ruben
A1 - Stepec, Biwen An
A1 - Bäßler, Ralph
A1 - Becker, Roland
A1 - Dimper, Matthias
A1 - Feldmann, Ines
A1 - Goff, Kira L.
A1 - Günster, Jens
A1 - Hofmann, Andrea
A1 - Hesse, René
A1 - Kirstein, Sarah
A1 - Klein, Ulrich
A1 - Mauch, Tatjana
A1 - Neumann-Schaal, Meina
A1 - Özcan Sandikcioglu, Özlem
A1 - Taylor, Nicole M.
A1 - Schumacher, Julia
A1 - Shen, Yin
A1 - Strehlau, Heike
A1 - Weise, Matthias
A1 - Wolf, Jacqueline
A1 - Yurkov, Andrey
A1 - Gieg, Lisa M.
A1 - Gorbushina, Anna
T1 - A 30-year-old diesel tank: Fungal-dominated biofilms cause local corrosion of galvanised steel
N2 - The increased use of biodiesel is expected to lead to more microbial corrosion, fouling and fuel degradation issues. In this context, we have analysed the metal, fuel and microbiology of a fouled diesel tank which had been in service for over 30 years. The fuel itself, a B7 biodiesel blend, was not degraded, and—although no free water phase was visible—contained a water content of ~60 ppm. The microbial community was dominated by the fungus Amorphotheca resinae, which formed thick, patchy biofilms on the tank bottom and walls. The tank sheets, composed of galvanised carbon steel, were locally corroded underneath the biofilms, up to a depth of a third of the sheet thickness. On the biofilm-free surfaces, Zn coatings could still be observed. Taken together, A. resinae was shown to thrive in these water-poor conditions, likely enhancing corrosion through the removal of the protective Zn coatings.
KW - Fungal biofilms
KW - Biodiesel degradation mechanisms
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655014
DO - https://doi.org/10.1038/s41529-025-00731-2
SN - 2397-2106
VL - 10
IS - 1
SP - 1
EP - 14
PB - Springer Science and Business Media LLC
AN - OPUS4-65501
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pavlidis, Sotirios
A1 - Fischer, Eric W.
A1 - Opis-Basilio, Amanda
A1 - Bera, Ayan
A1 - Guilherme Buzanich, Ana
A1 - Álvarez-Sánchez, María
A1 - Wittek, Severin
A1 - Emmerling, Franziska
A1 - Ray, Kallol
A1 - Roemelt, Michael
A1 - Abbenseth, Josh
T1 - Ambiphilic Reactivity and Switchable Methyl Transfer at a T-Shaped Bi(NNN) Complex Enabled by a Redox-Active Pincer Ligand
N2 - We report the transition-metal-like reactivity of a geometrically constrained, ambiphilic bismuth(III) trisamide. Planarization of the Bi(III) center unlocks Bi−C bond formation when reacted with mild electrophiles (alkyl iodides and triflates) accompanied by two-electron oxidation of the utilized NNN pincer nligand. The preservation of the bismuth oxidation state is confirmed by single-crystal X-ray diffraction and X-ray absorption spectroscopy and corroborated by theoretical calculations. Sequential reduction of the oxidized ligand framework alters the reactivity of a generated Bi−Me unit, enabling controlled access to methyl cation, radical, and anion equivalents. The full [Bi(Me)(NNN)]+/•/− redox series was comprehensively characterized using NMR and EPR spectroscopy as well as spectro-electrochemistry. This work represents the first example of ligand-assisted, redox-neutral C−X bond splitting at bismuth, establishing a new paradigm for synthetic bismuth chemistry.
KW - Pincer ligand
KW - XAS
KW - Redox
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654948
DO - https://doi.org/10.1021/jacs.5c18955
SN - 0002-7863
VL - 148
IS - 2
SP - 2683
EP - 2692
PB - American Chemical Society (ACS)
AN - OPUS4-65494
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yao, Xingyu
A1 - Antunes, Margarida M.
A1 - Guilherme Buzanich, Ana
A1 - Cabanelas, Pedro
A1 - Valente, Anabela A.
A1 - Pinna, Nicola
A1 - Russo, Patrícia A.
T1 - Formation, Phase Transition, Surface, and Catalytic Properties of Cubic ZrO 2 Nanocrystals
N2 - Pseudocapacitance-type transition metal oxides have been extensively investigated as anodes for lithium-ion batteries (LIBs). Currently, they are also gaining attention for sodium-ion batteries (SIBs) due to their low volume change and safety. However, their performance in sodium storage remains limited, primarily due to the larger Na+ ion radius. Here, for the first time, an iron niobate is reported with a columbite structure as a high-Performance sodium storage anode. The presence of iron triggers the loss of long-rangeorder through disorder of the FeO6 octahedra local structure, subsequentlyallowing reversible sodium storage in an amorphous phase. Simultaneously, the formation of short-range ordered zigzag-chain structures within the NbO6 planes creates a “skeleton” that offers abundant active sites forpseudocapacitive ion storage and enhanced ion diffusion pathways. These characteristics of FeNb2O6 make it an effective intercalation host, offering high capacity along with fast Na+ kinetics, as demonstrated through operando and ex situ characterizations. It leads to an applicable reversible capacity (>300 mAh g−1) with a favorable average voltage of ≈0.6 V and excellent rate capability (180.4 mAh g−1 at a current density of 2 A g−1). This study provides insights into the development of intrinsically active transition metal oxides for Na+-ion intercalation.
KW - XAS
KW - Sodium-ion Batteries
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654955
DO - https://doi.org/10.1021/acs.chemmater.5c01483
SN - 0897-4756
VL - 37
IS - 21
SP - 8568
EP - 8580
PB - American Chemical Society (ACS)
AN - OPUS4-65495
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Liu, Yanchen
A1 - Guilherme Buzanich, Ana
A1 - Alippi, Paola
A1 - Montoro, Luciano A.
A1 - Lee, Kug‐Seung
A1 - Jeon, Taeyeol
A1 - Weißer, Kilian
A1 - Karlsen, Martin A.
A1 - Russo, Patrícia A.
A1 - Pinna, Nicola
T1 - FeNb 2 O 6 as a High‐Performance Anode for Sodium‐Ion Batteries Enabled by Structural Amorphization Coupled with NbO 6 Local Ordering
N2 - Pseudocapacitance-type transition metal oxides have been extensively investigated as anodes for lithium-ion batteries (LIBs). Currently, they are also gaining attention for sodium-ion batteries (SIBs) due to their low volume change and safety. However, their performance in sodium storage remains limited, primarily due to the larger Na+ ion radius. Here, for the first time, an iron niobate is reported with a columbite structure as a high-performance sodium storage anode. The presence of iron triggers the loss of long-range order through disorder of the FeO6 octahedra local structure, subsequently allowing reversible sodium storage in an amorphous phase. Simultaneously, the formation of short-range ordered zigzag-chain structures within the NbO6 planes creates a “skeleton” that offers abundant active sites for pseudocapacitive ion storage and enhanced ion diffusion pathways. These characteristics of FeNb2O6 make it an effective intercalation host, offering high capacity along with fast Na+ kinetics, as demonstrated through operando and ex situ characterizations. It leads to an applicable reversible capacity (>300 mAh g−1) with a favorable average voltage of ≈0.6 V and excellent rate capability (180.4 mAh g−1 at a current density of 2 A g−1). This study provides insights into the development of intrinsically active transition metal oxides for Na+-ion intercalation.
KW - SIB
KW - XAS
KW - Sodium-ion Batteries
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654931
DO - https://doi.org/10.1002/adma.202504100
SN - 0935-9648
VL - 37
IS - 46
SP - 1
EP - 13
PB - Wiley
AN - OPUS4-65493
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Faustino, Leandro A.
A1 - de Angelis, Leonardo D.
A1 - de Melo, Eduardo C.
A1 - Farias, Giliandro
A1 - dos Santos, Egon C.
A1 - Miranda, Caetano R.
A1 - Buzanich, Ana G.
A1 - Torresi, Roberto M.
A1 - de Oliveira, Paulo F.M.
A1 - Córdoba de Torresi, Susana I.
T1 - Urea synthesis by Plasmon-Assisted N2 and CO2 co-electrolysis onto heterojunctions decorated with silver nanoparticles
N2 - The N2 + CO2 co-electrolysis to urea synthesis has become a promising alternative to the energy intensive traditional processes for urea production. However, there are still challenges in this approach, especially due to the competition with HER (Hydrogen Evolution Reaction) leading to low efficiency. Electrochemistry assisted by localized surface plasmon resonance (LSPR) using metal nanoparticles has been reported to enhance different electrochemical reactions. Here we report an electrochemical LSPR assisted urea synthesis using Ag nanoparticles (NPs) supported on BiVO4/BiFeO3 catalyst mechanochemically synthesized. The electrochemical experiments were performed under dark and upon plasmon excitation at the LSPR region of Ag NPs. Our results demonstrated that exciting in the LSPR range, urea yield rate and Faradic efficiency were considerably improved with reduced overpotential, 19.2 μmol h− 1 g− 1 and FE 24.4% at +0.1 V vs RHE compared to 9.6 μmol h− 1 g− 1 and FE 9.4% at − 0.2 V vs RHE under dark conditions. Further in situ FTIR-RAS experiments for mechanism investigation revealed the presence of N-H and C-N intermediates and the real effect of Ag plasmon excitation on HER and N2 + CO2 co-electrolysis. Theoretical calculations confirm the energy of the species involved in C-N coupling as well the role of the complex catalytic sites, which agrees with XAS measurements.
KW - Plasmon-assited
KW - XAS
KW - Urea
KW - Electrocatalysis
PY - 2025
DO - https://doi.org/10.1016/j.cej.2025.163072
SN - 1385-8947
VL - 513
SP - 1
EP - 13
PB - Elsevier B.V.
AN - OPUS4-65492
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -