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Posters |
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In vitro corrosion and stress corrosion of biocompatible WE43 magnesium alloy
Amirhossein Jabbari Mostahsan1, Laura Spagnolo1,2, Fabian Bobner1, Zahra Silvayeh1, Peter Auer1, Fernando Gustavo Warchomicka1, Luca Cozzarini2, Josef Domitner1, 1Institute of Materials Science, Joining and Forming, Graz, Austria 2University of Trieste, Department of Engineering and Architecture,Trieste, Italy
Abstract: Biocompatible magnesium alloys are promising candidates for temporary implants, as these bioabsorbable materials eliminate the need for secondary surgery to remove the implant after healing. The aim of this study is to investigate the in vitro stress corrosion behavior of extruded WE43 magnesium alloy under constant loading in a physiological environment. The microstructure and mechanical properties of the alloy were characterized, and its corrosion behavior was investigated in Hanks’ balanced salt solution (pH = 7.4) at the body temperature of 37 °C using potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS) and immersion tests. For in vitro stress corrosion testing, an experimental setup was developed using the loading system of a creep test machine to constantly load tensile specimens for up to one month in Hanks’ solution. A damage model as function of time and applied stress was developed based on the observed stress corrosion results, providing a foundation for predicting the lifetime of temporary magnesium alloy implants. |
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Click Chemistry Meets Germanium: Synthesis and Characterization of Click-Functionalized Acyl Germanes
Andre Stephan Culum, Institute of Inorganic Chemistry, Graz University of Technology
Abstract: Click chemistry has become an essential tool in modern chemical synthesis, enabling rapid and selective molecular assembly across various disciplines. Its bioorthogonality and biocompatibility have driven advancements in drug discovery, materials science, and particularly biomolecular engineering. With high functional group tolerance and modularity, it accommodates a broad range of substrates.[1] Our goal was to apply the properties of click chemistry to germanium based potoinitiators new and interesting substrates.
In this work, we present the synthesis and properties of acyl germane compounds designed for click chemistry. Desired compounds were prepared from the well-established trisacylgermenolate 1.[2] The prepared alkynes (2) and azides (3) underwent a copper catalysed azide-alkyne Huisgen cycloaddition with various substrates, tailoring for their (4 and 5) spectroscopic properties as well as their lipo- and hydrophilicity (Scheme 1). These substrates include a variety of aromatic and some aliphatic compounds, carbohydrates, and amino acids (abbreviated as R in Scheme 1).
Scheme 1: Synthesis of acyl germane azides and alkynes and their respective cycloaddition products.
References
[1] R. D. Row, J. A. Prescher, Acc. Chem. Res. 2018, 51, 1073-1081.
[2] M. Drusgala, M. Paris, J. Maier, R. C. Fischer, M. Haas, Organometallics 2022, 41, 2170– 2179.
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Alternative solid-state synthesis methods for lead-free (Ba,Ca)(Zr,Ti)O3 piezoceramics based on the interdiffusion of intermediate perovskites
Anna Paulik
Abstract: The piezoelectric (Ba,Ca)(Zr,Ti)O3 (BCZT) material system is a promising alternative to conventional lead-based materials for soft ferroelectric application like actuators, sensors, and haptic devices. However, reliable and reproducible performance, which is critical for commercialization, is dependent on the microstructure and processing parameters of BCZT. Due to the large number of constituents, the conventional solid-state synthesis of BCZT from oxide and carbonate precursors involves a complex formation reaction sequence, including perovskite and non-perovskite intermediates. This leads to reports of residual secondary phases, as well as poor reproducibility of functional properties.
In our study, we propose an alternative solid-state synthesis method for BCZT, based on an interdiffusion process between binary or ternary intermediate perovskite phases, which dramatically reduces the complexity of the synthesis.
We verify our approach using diffusion couple experiments of intermediate persovkite oxides and high-temperature in-situ X-ray diffraction. After calcination and sintering, our samples exhibit a dense and almost single-phase microstructure, comparable to that of conventional BCZT, as well as similar or in some cases even improved piezoelectric performance.
Our findings illustrate that synthesizing BCZT piezoceramics via a purely diffusion-based process is not only possible, but might even be advantageous, compared to a conventional solid-state reaction from mixed oxides and carbonates. |
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Fatigue life assessment and hygrothermal aging of wood-polymer hybrid joints
Awais Awan, Institute of Materials Science, Joining and Forming (IMAT)
Abstract: There is an increasing trend towards lightweight hybrid structure applications in the transportation sector, driven by demand to mitigate greenhouse gas emissions. The metal-polymer hybrid structures produced by novel joining techniques have gained popularity in recent years. However, wood-polymer joints are being made using ultrasonic joining (U-Joining) more recently. U-Joining is a solid-state, friction-based joining technique that can combine wood with polymer through high-frequency mechanical vibrations using frictional heat. In this study, U-Joining was applied to combine beech wood with additively manufactured polyamide reinforced with short carbon fibers. The understanding and optimization of the U-Joining process for producing beech/PA6-15CF joints have already been studied. However, the mechanical performance of these joints under cyclic loading, as well as the effects of temperature and humidity cycling on their quasi-static strength, have not yet been investigated. Therefore, in this study, the beech/PA6-15CF joints were subjected to cyclic loading under four different percentage levels of ultimate lap-shear force. The fatigue life was predicted using a two-parameter Weibull distribution. The fatigue life was calculated as 500 N or 24% of ULSF at one million cycles. The joints surviving one million cycles were tested under quasi-static loading, and a reduction of only 18% was measured; the joint failed with cohesive failure on the wood side. Moreover, the beech/PA6-15CF joints were also subjected to hygrothermal aging for one week. The temperature and humidity were based on the ISO 9142 D3 cycle, where the temperature range from -20 °C to 70 °C and the relative humidity range from 50% to 90%. There was a substantial decrease of 60% in the quasi-static lap-shear strength of joints after one week. |
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Using $in-situ$ and $operando$ X-ray powder diffraction and $^7$Li NMR to monitor solid-state reactions in batteries.
B. Gadermaier and H. M. R. Wilkening, Institute for Chemistry and Technology of Materials
Abstract: NMR and XRD are both contact-free methods capable of “looking” inside closed systems and offer valuable insight into (electro)-chemical solid-state reactions in batteries. In particular, $operando$ $^7$Li NMR offers insight into dynamics, while XRD offers a unique insight into solid-solid phase transitions, which are essential for understanding cell voltages in Li-ion batteries.
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Towards Efficient and Reproducible Perovskite–Organic Tandem Solar Cells
Bernadette Ortner
Abstract: Perovskite–organic tandem solar cells represent a promising pathway toward high-efficiency photovoltaics by combining complementary absorber materials. Both perovskite and organic sub-cells exhibit strong standalone performance, providing a solid foundation for tandem integration. In this work, we show that careful engineering is required to fully translate high sub-cell performance into high tandem efficiency.
The interlayer design and sub-cell matching play a crucial role in achieving optimal device performance. While several functional interlayers are available, their optimal combination and processing remain to be refined.
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In-situ and Operando Observation of the Anode Growth Morphology in Secondary Aluminium Batteries
Bernhard Gollas, Institute for Chemistry and Technology of Materials
Abstract: Secondary aluminium batteries are considered possible candidates for replacing lithium-ion cells in future electrochemical energy storage technology [1]. As in all rechargeable batteries with metal anodes, however, the growth morphology also of aluminium during charging is an issue [2]. This morphology ideally should be compact in order to avoid short circuits and device failure by the formation of dendrites. Non-compact aluminium morphologies might also result in the formation of “dead” aluminium during discharge, which compromises the capacity. We found several parameters affecting the anode growth morphology in secondary aluminium-sulphur batteries, including the current density, the areal charge density, the type of current collector, and the electrolyte composition. Commonly used electrolytes in rechargeable aluminium batteries contain chloroaluminates either in classical ionic liquids or in so-called deep eutectic solvents, which are economically more viable [3]. All of these chloroaluminate electrolytes are moisture sensitive and highly corrosive. One way of mitigating these disadvantages in case of cell leakage is to use such electrolytes in the form of polymer gels [4]. The addition of polymeric additives can significantly affect the aluminium growth morphology and thus needs to be studied. Commonly used ex-situ methods for characterization, like scanning electron microscopy, however, are not suitable here. Cell disassembly and removal of the sticky polymer gel electrolyte from the anode before inspection in the microscope mostly causes significant changes in the surface morphology. In order to obtain meaningful and unambiguous results, it is essential to observe the growth morphology in situ. We will show examples of such studies based on optical video microscopy and X-ray micro computed tomography.
Acknowledgements
Funding of this work by the EU H2020-FETOPEN-1-2016-2017 SALBAGE (G.A. 766581) and FET-PROACT-EIC-06-2019 AMAPOLA (G.A. 951902) projects is gratefully acknowledged.
References
[1] T.M. Gür, Review of electrical energy storage technologies, materials and systems: Challenges and prospects for large-scale grid storage, Energy Environ. Sci. 11 (2018) 2696–2767.
[2] G.A. Elia, K. Marquardt, K. Hoeppner, S. Fantini, R. Lin, E. Knipping, W. Peters, J.-F. Drillet, S. Passerini, R. Hahn, An Overview and Future Perspectives of Aluminum Batteries, Adv. Mater. 28 (2016) 7564–7579.
[3] M. Malik, K.L. Ng, G. Azimi, Physicochemical characterization of AlCl3-urea ionic liquid analogs: Speciation, conductivity, and electrochemical stability, Electrochim. Acta. 354 (2020) 136708.
[4] Á. Miguel, P. Jankowski, J. L. Pablos, T. Corrales, A. López-Cudero, A. Bhowmik, D. Carrasco-Busturia, G. Ellis, N. García, J. M. García-Lastra, P. Tiemblo, Polymers for aluminium secondary batteries: Solubility, ionogel formation and chloroaluminate speciation, Polymer 224 (2021) 123707.
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Ultrasonic-Assisted Polishing of Internal Surfaces in Cast Pump Casings
Christian Schmidt
Abstract: The internal surfaces of pump casings are exposed to stresses such as corrosion, abrasion, and cavitation. Improving surface quality in these areas enhances pump efficiency and durability, but conventional polishing methods struggle with complex geometries and limited accessibility. This work investigates an ultrasonic-assisted abrasive polishing process using a water–aluminum oxide mixture activated by an ultrasonic transducer inside a sealed test rig. Key parameters—ultrasonic power, abrasive concentration, and polishing time—were studied using a Design of Experiments approach. Surface roughness measurements before and after treatment indicate that the method can achieve localized improvements, with the best results obtained at high ultrasonic power and low abrasive concentration. These findings confirm the feasibility of ultrasonic-assisted polishing and provide a foundation for further optimization to achieve more consistent improvements in internal pump casing surfaces. |
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Novel aluminium-carbon nanomaterials fabricated by means of friction stir processing and plasma/electron beam welding
Christoph Schellander
Abstract: Modern technical applications demand materials that combine high electrical conductivity with high strength, although conventional aluminum alloys typically exhibit a trade-off between these properties - EN AW-6061 therefore serves as a reference material in this work. Recent research describes aluminum–carbon covetics as a promising approach, as they are reported to potentially improve conductivity and strength simultaneously by integrating carbon into the metal matrix - a locally discussed bonding character with both metallic and covalent contributions is proposed as a possible explanation. Established covetic manufacturing routes, however, are complex and commonly rely on electrically assisted casting.
This work investigates an alternative route that imitates the electrically assisted casting concept without implementing conventional casting. Carbon is first distributed as homogeneously as possible in the base material and then processed via different routes—partly joining-based and partly via additional steps—to create functionally equivalent conditions. Specimens are characterized by electrical conductivity measurements and metallographic analyses, and results are interpreted and compared with literature to evaluate the suitability of the investigated approach for producing and/or understanding aluminum–carbon covetics. |
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Functionalized Hydrosilanes – Novel Precursors for Liquid Phase Deposition (LPD)
Daniel Griess, Graz University of Technology
Abstract: State-of-the-art techniques for the production of semiconductors via single-crystal wafer silicon suffer from
high costs because of the high energy demands as well as the generation of large amounts of waste, as only
25% of the single-crystal silicon can be used. [1] Hydrosilanes (HS) have already shown that these problems
can be circumvented, as they are promising starting materials for the synthesis of high-quality silicon layers by
liquid phase deposition. [2,3] However, many studies with the goal to prepare functionalized thin-films (doping)
ran into severe problems with homogeneity, solubility of doping agents etc. For this study we introduced
carbon functionalized hydrosilanes (FHS) as single precursors for thin-film deposition.
Moreover, we will discuss the quality and the composition of the obtained thin-film silicon layers. [4] |
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Unlocking Complex Anisotropic Hydrogel Constructs via Support-Enabled Cellulose Ink 3D Printing
Daniel Pint, Institute of Chemistry and Technology of Biobased System (IBioSys)
Abstract: Three-dimensional (3D) printing of hydrogels has enabled new directions in biomedical engineering, soft material design, and biofabrication. However, unsupported hydrogel inks often collapse under their own weight or deform during printing, limiting achievable geometries.[1,2] We present a reproducible, standardized support system combining a nanofibrillated cellulose/sodium alginate (NFC/ALG) structural ink with a cellulose-based sacrificial support ink composed of NFC, hydroxyethylcellulose (HEC) and CaCl2, building on established NFC-based hydrogel systems and support-assisted printing concepts.[3,4] Quantitative validation using tubular models shows that unsupported tubes collapse before 50 mm height, whereas supported tubes remain upright and stable. Surface fidelity is substantially improved by reducing layer height, yielding watertight prints. Demonstrations of complex geometries, including an anatomical aorta, confirm the method’s capability. Support dissolution in 30 mM CaCl2 occurs over approximately 3 days, ensuring stability during crosslinking and handling. Compared with other sacrificial strategies, this approach is inexpensive, cellulose-based, and relies on mild ionic crosslinking compatible with future cell-laden systems. This work provides a robust and accessible hydrogel engineering system, supporting stable and high-fidelity DIW of complex anisotropic structures.
[1] F. Lackner, et al., Advanced Materials Technologies, 2023, 8, 2201708.
[2] Skylar-Scott et al., Science Advances, 2019, 5, eaaw2459.
[3] T. J. Hinton, et al., Science Advances, 2015, 1, e1500758.
[4] K. Markstedt, et al., Biomacromolecules 2015, 16, 1489
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Monitoring a traceless conjugation of peptides to polysaccharides
David Bucak Gasser, Institute of Chemistry and Technology of Biobased Systems (IBioSys)
Abstract: Native chemical ligation (NCL) refers to the well-known formation of an amide bond between a C-terminal thioester and an N-terminal cysteine of peptides or proteins. High chemoselectivity, complete avoidance of protective groups on amino acid residues and compatibility with aquoeus, physiological conditions make NCL a biologically benign and effective method for synthesis of polysaccharide-peptide conjugates, which are becoming increasingly pivotal in the development of targeted drug delivery systems, vaccines and tissue engineering scaffolds. Our work introduces in situ, real-time monitoring of a highly robust, peptide-to-polysaccharide NCL method. |
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$CO_2$ Activation of Polydicyclopentadien-Based Hard Carbon for Long Cycle Life Na-Ion Battery Anodes
David Schuster, Glen Smales, Max Schmalleger, Bernd Fuchsbichler, Stefan Koller, Christian Slugovc, CD Laboratory for Oranocatalysis in Polymerization; VARTA Innovation GmbH
Abstract: As an unidentical twin to lithium-ion batteries (LIBs), sodium-ion batteries (SIBs) are widely considered a promising alternative due to the abundance and low cost of raw materials. However, the development of high-performance and cost-effective electrode materials remains a significant challenge, particularly when competing with lithium iron phosphate (LFP) systems. [1,2,3] Herein, we present a hard carbon (HC) material derived from inexpensive and readily available poly(dicyclopentadiene) for use as a negative electrode in SIBs. This study investigates the influence of carbonization temperature and subsequent $CO_2$ activation on the HC's structure and electrochemical performance. The impact of activation proved to be dependent on the first stage carbonization temperature, creating more disorder for samples carbonized at 900°C and higher local order for samples carbonized at 1350°C. The removal of defects and increase in average graphitic nano domain length resulted in a turbostratic structure that led to an enhanced rate performance and capacity retention when compared with non-activated samples. The optimized HC exhibits a reversible capacity of 352 mAh/g and a capacity retention of 93% after 200 cycles. This work introduces a cost-effective approach for producing hard carbon materials with distinctive nanostructure and provides valuable insights into achieving long cycle life in sodium-ion batteries.
[1] Vaalma, C.; Buchholz, D.; Weil, M.; Passerini, S. A Cost and Resource Analysis of Sodium-Ion Batteries. Nat. Rev. Mater. 2018, 3. https://doi.org/10.1038/natrevmats.2018.13.
[2] Karabelli, D.; Singh, S.; Kiemel, S.; Koller, J.; Konarov, A.; Stubhan, F.; Miehe, R.; Weeber, M.; Bakenov, Z.; Birke, K. P. Sodium-Based Batteries: In Search of the Best Compromise Between Sustainability and Maximization of Electric Performance. Front. Energy Res. 2020, 8 (December), 1–16. https://doi.org/10.3389/fenrg.2020.605129.
[3] Guo, W.; Feng, T.; Li, W.; Hua, L.; Meng, Z.; Li, K. Comparative Life Cycle Assessment of Sodium-Ion and Lithium Iron Phosphate Batteries in the Context of Carbon Neutrality. J. Energy Storage 2023, 72 (February). https://doi.org/10.1016/j.est.2023.108589.
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IsoME: Streamlining High-Precision Eliashberg Calculations
Dominik Spath, Institute of Theoretical and Computationl Physics
Abstract: Ever since the discovery of superconductivity, efforts have been made to understand the nature of the superconducting phase. The theoretical treatment of conventional superconductivity is based on Migdal-Eliashberg theory. Although Migdal-Eliashberg theory has been available since the 1960s, progress in the field of superconductivity has historically been driven by experimental discoveries. However, the exponential growth in computational power over the past decades, coupled with the development of highly efficient and accurate numerical codes, enables the discovery of novel crystals and the determination of their superconducting properties entirely from first principles.
We present the very efficientJulia package IsoME, which can calculate superconducting properties at different levels of approximation within the framework of isotropic Migdal-Eliashberg theory.
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Enhancing the Photovoltaic Properties and Operational Stability of Tin-Lead Perovskite Solar Cells Using a Terthiophene-Based Additive
Dzaky Ruhimat, Alexander Holzer, Suman Mallick, Thomas Rath, Gregor Trimmel, Institute of Chemistry and Technology of Materials
Abstract: Tin-lead (Sn-Pb) narrow band-gap perovskites have emerged as promising photoabsorbers for efficient single-junction and tandem solar cells. However, the susceptibility of Sn$^{2+}$ ions to oxidation and the distinctly different crystallization rates of tin- and lead-halide perovskites present challenges, as they can promote the formation of non-beneficial crystal defects that adversely affect optoelectronic properties and long-term stability. In this study, we develop a novel terthiophene-based additive, particularly 3ThDMA, to act as bulk defect passivator, and compare it with EDAI$_{2}$ as widely-utilized defect passivation additive. The addition of 0.4 mol% of 3ThDMA boosts the efficiency of 50:50 composition Sn-Pb-based solar cells in p-i-n architecture (glass/ITO/PEDOT:PSS/$Cs_{0,1}MA_{0,3}FA_{0,6}Sn_{0,5}Pb_{0,5}I_{3}$/$C_{60}$/BCP/Ag) to 17.1%, while solar cells with the same amount of EDAI$_{2}$ only reveal efficiencies up to 14.9%. Furthermore, the 3ThDMA-based solar cells retain over 40% of their initial efficiency after 140 hours of air exposure, whereas EDAI$_{2}$-based cells only maintain 20% under the same exposure conditions. |
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Electrostatic Design of Porous Materials
Egbert Zojer
Abstract: Collective electrostatic effects significantly impact the electronic structures of hybrid interfaces and surfaces.[1] They arise from the superposition of electrostatic potentials of periodically arranged (di)polar entities and have severely impacted our understanding of surfaces. In this contribution, I will discuss, how collective electrostatics could be used outside the beaten paths of materials design for realizing systems with advanced and sometimes unprecedented properties.[2] The idea of aligning dipoles at interfaces has been extensively explored for tuning injection properties at electrodes, changing contact resistances in organic transistors by up to three orders of magnitude.[3] Of particular interest in the present context is how electrostatic design could be exploited in metal-organic and covalent-organic frameworks (MOFs and COFs).
Regarding MOFs, we have explored the inclusion of polar linkers into thin films, which allows the realization of electrostatic potential gradients within MOF structures.[4],[5] The not fully resolved challenge here is how to achieve an alignment of polar apical linkers in pillar-layer MOFs in a non-centrosymmetric fashion.[5] In contrast, COF-structures with polar groups decorating pore walls are rather common, even though the collective electrostatic effects resulting from the periodic alignments of polar groups have been largely overlooked. This can be problematic, when interpreting experimental results dealing with catalysis, battery application and excited-state charge-transfer processes. This is a consequence of the fact that polar substituents at pore walls can shift the electrostatic energy within the pores by clearly more than one eV.[6] This has severe consequences for the relative alignment of electronic states in the COFs and in guest molecules contained in the pores. [6],[7] The electrostatically induced shifts are relatively insensitive to local defects and COF stacking faults, Moreover, they can be selectively tuned by post-synthetic modification reactions.[7] This opens up the possibility of realizing potential pockets or potential gradients within the pores,[7] which could eventually be used for localizing ionic guest molecules or for driving them into specific directions.
References
[1] Egbert Zojer, Thomas C. Taucher, and Oliver T. Hofmann, Adv. Mater. Interf. 2019, 1900581 (Hall of Fame Review).
[2] Egbert Zojer, Adv. Mater. 2024, 2406178 (invited Perspective Article).
[3] Andreas Petritz, et al., Adv. Funct. Mater. 2018, 28, 1804462.
[4] Giulia Nascimbeni, Christof Wöll, and Egbert Zojer, Nanomaterials 2020, 10, 2420 (Editor’s choice).
[5] Alexei Nefedov et al., Adv. Mater. 2021, 2103287.
[6] Egbert Zojer, Nano Lett. 2023, 23, 3558–3564
[7] Egbert Zojer, J. Mater. Chem. A 2024, 12, 10166-10184 (Editor’s Choice Collection)
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Modification of electrode surfaces for CO2-capture
Elena Heinzel, Institute for Chemistry and Technology of Materials
Abstract: The rapid increase in anthropogenic carbon dioxide ($CO_2$) emissions to the atmosphere since the industrial revolution is considered one of the greatest challenges of our time. According to the Intergovernmental Panel on Climate Change (IPCC), meeting the criteria of the Paris Agreement on Climate requires not only drastic emission reduction measures, but also the fast implementation of carbon capture utilization and storage (CCUS) technologies. [1]
State-of-the-art technologies are based on the use of diverse amine-solutions, which effectively absorb $CO_2$ from exhaust gas flows. The captured $CO_2$ is released and by thermal-/pressure driven desorption. Although so-called amine scrubbing offers a high technological readiness levels (TRL) of 7-9, there are many disadvantages due to the high energy demands for heating and the large physical footprint as well as the involvement of potentially hazardous chemicals. [2, 3]
Electrochemical carbon capture and concentration (eCCC) is a promising alternative to traditional thermochemical processes. Redox-active molecules, such as transition metal complexes, pyridines, dithiols and quinones, have been successfully proven to efficiently and reversibly bind $CO_2$. [3, 4]
In this work, glassy carbon electrodes were successfully modified with different quinones using chemical and electrochemical grafting methods. These electrodes were then further investigated for their ability to reversibly bind dissolved $CO_2$ from different electrolytes.
[1] L. Hoesung, et al., Climate Change 2023 – Synthesis Report, 2023, 01–44.
[2] D.M. D’Alessandro, et al.,Angewandte Chemie International Edition, 49 (2010), 6058-6082.
[3] M. Stern, et al., Energy & Environmental Science, 6 (2013), 2505.
[4] A. Zito, et al., Chemical Reviews, 123 (2023), 8069-8098.
[5] Y. Liu, et al., Nature Communications, 11 (2020), 2278.
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STEM-Based Defect Detection in doped SrTiO3
Elena Unterleutner, Institute of Electron Microscopy and Nanoanalysis (FELMI)
Abstract: Introduction
Atomic-scale defect detection in complex oxides such as SrTiO$_3$ (STO) is crucial for optimizing their functional properties. The controlled introduction of dopants and vacancies enables precise tuning of electronic and magnetic behavior, making detailed knowledge of their structural and electronic configurations essential. In this study, we present a comprehensive approach that refines the entire workflow, from advanced sample preparation to sophisticated data analysis, for reliable point defect characterization using aberration-corrected scanning transmission electron microscopy (STEM).
Methods
To develop and optimize defect characterization techniques, we investigate STO doped with low concentrations of Ta. The atomic-scale distribution and defect structures introduced by doping are analyzed by correlating information from integrated differential phase contrast (iDPC) and high-angle annular dark-field (HAADF) imaging.
Multislice (MS) simulations are employed to optimize experimental parameters, while precise sample preparation techniques, including wedge polishing, ensure optimal imaging conditions. Extremely thin samples (<18 unit cells) were prepared, and their thickness was verified using position-averaged convergent beam electron diffraction (PACBED) to enable direct comparison with MS simulations. The primary focus of this study is to investigate the point defects comprised of O and Sr vacancies associated to adjacent Ta dopants. By integrating simultanous HAADF and iDPC imaging, we systematically examine the spatial correlation between Ta dopants, Sr vacancies, and oxygen vacancies in doped STO.
Results
Our findings confirm the presence of Ta dopants in STO using HAADF imaging. The results further suggest a correlation between Ta incorporation and the formation of Sr vacancies. Additionally, iDPC-based oxygen vacancy detection indicates a potential link between O vacancies, Sr vacancies, and Ta dopants.
Discussion and conclusions
These results contribute to the ongoing development of robust, quantitative approaches for defect analysis in complex oxides. Current efforts focus on refining data analysis techniques to establish a reliable defect characterization framework, which can be extended to other complex oxide material systems. By systematically optimizing both experimental and analytical methods, this study advances atomic-scale defect quantification, paving the way for improved control over functional properties in doped oxides.
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Recycled Plastics in Focus: Analytical Strategies for Assessing Food Contact Safety
Elise Hecht, Institute of Analytical Chemistry and Food Chemistry
Abstract: To support the transition towards a circular economy for plastics, the European Union has set ambitious targets for the recycling and reuse of packaging materials, including food-packaging. By 2030, the minimum content of post-consumer recycled (PCR) plastic should be 30% for PET-based packaging and single-use plastic bottles, and 10% for non-PET packaging in contact-sensitive applications.[1]
This is supported by the recently introduced Regulation (EU) 2022/1616, which deals specifically with recycled plastics intended for food contact. In this regulation, a framework for the development of new recycling technologies (novel technologies) for polymers beyond PET is established. Products that result from a novel technology are allowed to enter the market before the process is fully evaluated and authorized by the European Food Safety Authority (EFSA). To ensure that the materials meet the safety standards for food contact materials set out in regulations (EC) No 1935/2004 and (EU) No 10/2011, strict monitoring and regular safety reports are required. This includes providing detailed data on contaminants in both the input and the output material of the recycling process.[2]
However, to date, no standardized analytical methods are available to generate the required data. Therefore, the aim of this work is to characterize different post-consumer recycled plastics, focusing on polyolefins such as HDPE, LDPE or PP. This is done by applying different sample preparation methods such as solid-phase microextraction (SPME), solvent extraction or migration experiments. These are then combined with targeted and untargeted analytical methods, primarily based on gas chromatography (GC-FID, GC-MS, GC×GC-ToFMS) as well as liquid chromatography. In addition, a genotoxic screening of the materials is performed. The resulting data will contribute to the development of a comprehensive database, which will serve as a foundation for an automated assessment strategy for PCR plastics.
[1] http://data.Europa.eu/eli/reg/2025/40/oj
[2] http://data.Europa.eu/eli/reg/2022/1616/oj
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Pathway to High Temperature Superconductors: Theoretical Insights into BaSiH8
Eva Kogler
Abstract: High-pressure hydrides are an excellent example of the success story of computational
material design. Highly accurate and reliable ab-initio methods and increasing
computational power made it possible to predict novel materials to guide experiments,
which are often expensive and time consuming. In the theoretical analysis of materials,
it is important to assess stability and metastability from thermodynamic, dynamic, and
kinetic perspectives.
The investigation becomes particularly intricate for hydrogen-rich materials due to the
light mass of hydrogen atoms, which can induce anharmonic and quantum ionic
effects. Traditionally, studying these effects would require thousands or even hundreds
of thousands of DFT calculations. However, the use of machine-learned interatomic
potentials within the framework of SSCHA accelerates this process by more than 10^4
times, while maintaining DFT-level accuracy. One can therefore consider larger
supercells and significantly improve the convergence of the calculations. By
accounting for anharmonic and quantum ionic effects, a more precise estimation of
stability and the critical superconducting temperature (Tc) can be achieved.
I will present the findings of our comprehensive investigation into the stability of
BaSiH8, a hydride superconductor with a Tc above 70 K. (Lucrezi et al., npj Computational Materials, 8(1):119, 2022 and Lucrezi et al., Commun. Phys. 6, 298, 2023) |
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Entropy Measurements to Investigate Hard Carbon as a Battery Active Material
Felix Niedersüß, Institute for Chemistry and Technology of Materials
Abstract: The ever-rising demand for both electrical energy and its storage urges the advancement of increasingly efficient forms of batteries. While lithium-ion batteries (LIBs) have been the status quo for rechargeable energy storage for over two decades, concerns over the sustainability of this technology call for the development of a new type of battery. Sodium-ion batteries (SIBs) are a promising alternative to its alkali-metal neighbor lithium, being cheap and eco-friendly, with high capacity and cyclability. However, some established battery materials like graphite anodes in LIBs cannot be adopted for use in SIBs. Instead, hard carbon, an amorphous form of carbon, has shown to be a suitable replacement for the use as anode in SIBs. Its disordered nature gives rise to a number of possible ion storage mechanisms which are not fully understood yet, with previous research having produced contradictory results.
Entropymetry is a method that has not yet been applied for the in-situ characterization of hard carbon. It aims to investigate the storage mechanisms of ions in an electrode based on their effect on the entropy of the material. This is made possible via a combination of thermodynamics and electrochemistry, linking the entropy change to the cell's potential response with respect to temperature. Using this connection, entropy measurements can be performed across a wide range of states of charge, creating an entropy profile that gives an insight into the ongoing processes inside the cell.
This work presents the initial results of a set of entropymetry measurements performed on a sodium-ion half-cell with hard carbon as the working electrode. It acts as a proof of concept that reliable data can be produced using this method. The entropy profile shows distinct regions where different storage mechanisms might be active, reinforcing the results from previous investigations into hard carbon electrodes. However, it also indicates areas where improvements have to be made in order to achieve optimal results, prompting further development of this method. |
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Investigation of materials properties with Brillouin light scattering and machine learned interatomic potentials
Florian P. Lindner , Institute of Solid State Physics
Abstract: Metal–organic frameworks (MOFs) are substantially more mechanically compliant than conventional inorganic materials due to their open framework architectures and the flexibility of their building units. Their low elastic moduli, particularly in activated structures, make MOFs highly susceptible to pressure-induced structural collapse [1], which can lead to gradual performance degradation. A detailed understanding of structure–mechanical property relationships is therefore crucial for their practical application. Experimentally, mechanical properties of MOFs are commonly probed using (powder) X-ray diffraction or indentation techniques. However, these approaches either lack directional sensitivity or are prone to significant errors when elastic anisotropy is not properly accounted for.
Brillouin light scattering (BLS) offers a powerful, completely non-invasive alternative, enabling direct measurement of direction-dependent sound velocities corresponding to ultra-low-frequency acoustic phonons [2]. From these measurements, the full elastic tensor and thus the complete elastic response of the material can be derived. For MOFs, this approach was first demonstrated in the seminal work of Tan et al. [3]. In this work, we demonstrate how a tight integration of BLS experiments with atomistic simulations, combining state-of-the-art density functional theory and machine-learned interatomic potentials (MLIPs) [4], enables a robust and efficient investigation of MOF mechanical properties [5]. The excellent agreement between experiment and simulation, together with the orders-of-magnitude computational speedup provided by MLIPs, allows systematic exploration of elastic and thermoelastic behavior. Building on this approach, we aim to significantly broaden the range of materials studied in the near future, extending beyond MOFs to establish general structure–property relationships across a wider class of complex materials, including their behavior at elevated temperatures, pressures, and under dynamic conditions.
[1] I. E. Collings et al. J. Appl. Phys. 126, 181101, 2019.
[2] I. Kabakova et al. Nat Rev Methods Primers 4, 8, 2024
[3] JC. Tan et al. PRL 108, 095502, 2012
[4] S. Wieser et al. npj Comput Mater 10, 18, 2024
[5] F. P. Lindner et al. J. Phys. Chem. Lett. 16, 1213-1220, 2025
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Applying machine-learning approaches for a quantitatively reliable description of heat transport in MOFs
Florian Unterkofler, Institute of Solid State Physics
Abstract: Heat conduction in MOFs is a crucial requirement for any application in which excess heat needs to be dissipated or supplied (e.g., for gas adsorption/desorption or catalysis). As most MOFs are electrical insulators, they transport heat as lattice vibrations, which can be described either in real space via lattice vibrations or in reciprocal space via phonons. To develop reliable structure-to-property relations for heat transport, an atomistic understanding of the underlying processes is crucial. This can be best achieved via atomistic computer simulations, provided that they are capable of describing the relevant processes accurately.
This raises two fundamental questions: which computational approach should be chosen to describe thermal transport, and how could one reliably describe the involved inter-atomic interactions. For the latter, density functional theory (DFT) would be the natural choice, but DFT is not efficient enough to calculate forces between (tens of) thousands of atoms several million times. At the other end of the computational spectrum would be classical, transferable force fields, but they are way too inaccurate for providing a reliable description of MOF properties. These dilemmas can be resolved by using force fields system-specifically trained against DFT data, where we focus on moment-tensor potentials trained via a specially adapted active learning approach.[1], [2] They yield essentially DFT accuracy at sharply reduced computational costs (with a speedup compared to DFT of approximately 1010 estimated for the largest considered systems). This allows a quantitatively reliable description of heat transport processes for MOFs[1] as well as for molecular crystals.[3] Notably, the excellent agreement between experiments (often on single crystals) and simulations is achieved both when extracting thermal conductivities from the particle trajectories of non-equilibrium molecular dynamics simulations[1],[4] as well as when basing the analysis on harmonic and anharmonic phonon properties.[3],[4]
The distinct advantage of considering both approaches is that they provide complementary insight into the physical aspects of heat transport: from an analysis of the real-space effective temperature distribution in MOFs subject to a thermal gradient, one can, for example, identify the connections between linkers and nodes as the bottlenecks to thermal transport in MOF.[4],[5] In contrast, analyzing the phonon dynamics shows that in low thermal-conductivity materials like MOFs or molecular crystals it is not sufficient to describe heat transport merely as a diffusive transport of particle-like phonons. Rather, one also needs to consider coherences contributions arising from phonon tunneling between the lifetime-broadened phonon bands. This has the consequence that not only low-frequency acoustic phonons contribute to heat transport, but that also more complex, higher-lying optical phonons become relevant.
[1] S. Wieser and E. Zojer. npj Comput. Mater. 2024, Vol., 10-18
[2] N. Strasser, S. Wieser, and E.Zojer. Int. J. Mol. Sci. 2024, Vol., 25-3023
[3] L. Legenstein, L. Reicht, S. Wieser, M. Simoncelli, E. Zojer. npj Comput. Mater. 2025, Vol., 11-29
[4] S. Wieser, T. Kamencek, J. P. Dürholt, R. Schmid, N. Bedoya-Martínez, E. Zojer. Advanced Theory and Simulations. 2021, Vol., 4-2000211
[5] S. Wieser, T. Kamencek, R. Schmid, N. Bedoya-Martínez, and E. Zojer. Nanomaterials. 2022, Vol., 12-2142
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Effects of Water Uptake on Interfacial Adhesion of Wood-Polymer Joints Produced by Additive Manufacturing
Gean Marcatto , Institute of Materials Science, Joining and Forming
Abstract: This research investigates the interfacial adhesion and environmental durability of hybrid joints composed of beech wood and carbon fiber-reinforced polyamide 6 (PA6-15CF) produced via the AddJoining process. The methodology utilizes a three-step additive manufacturing approach, including substrate positioning, first layer deposition, and standard fused filament fabrication, during which interfacial temperatures reach between 180 °C and 195 °C to facilitate polymer filling in the wood surface roughness. While dry specimens exhibit strong structural integrity characterized by direct hydrogen bonding between the polymer amide groups and wood hydroxyl groups and evidenced by specific blue shifts in ATR-FTIR spectra at the Amide I, Amide II, and N-H stretching bands, these joints are highly susceptible to moisture-induced degradation. Environmental testing demonstrates that while storage at 50% humidity results in minimal water gain and preserves a lap-shear strength of approximately 7.5 ± 0.5 MPa, full water immersion leads to a critical water uptake exceeding 35%. This saturation causes significant material swelling and plasticization, resulting in a dramatic reduction of the Ultimate Lap-Shear Strength to roughly 3 ± 0.7 MPa. Chemical analysis and scanning electron microscopy confirm that the failure mechanism is driven by the disruption of the interface, where absorbed water molecules replace direct Amide-Hydroxyl bonds with competitive "water bridges". These bridges shield the polymer-fiber interface and neutralize the natural interfacial H-bonding, ultimately weakening the adhesion and compromising the joint’s mechanical performance in wet environments. |
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Thermal modelling of dissimilar aluminium-copper refill friction stir spot welds
Georg Hauptmann, Institute of Materials Science, Joining and Forming (IMAT)
Abstract: Increasing environmental awareness and economic considerations are driving innovative product design and the adoption of advanced material combinations, thereby creating a demand for novel joining technologies. One such technology is refill friction stir spot welding (RFSSW), which enables the joining of dissimilar materials, such as aluminium and copper, making it particularly suitable for the manufacturing of busbars, for example in the automotive industry. Although the process temperatures in this solid-state welding technique are significantly lower than those during fusion welding, the formation of intermetallic layers at the aluminium-copper interface can still be observed. As their formation and thickness depend on temporal and thermal evolutions and significantly influence the mechanical and electrical properties of the joint, a numerical simulation was implemented using Abaqus/Explicit to model the temperature distribution and subsequently draw quantitative conclusions regarding the layer thickness. The novelty of the proposed approach lies in describing the heat input by means of analytical equations and representing the material flow through element activation and deactivation, which enables a substantial reduction in computational resources. To further reduce the calculation time, an axisymmetric model was adopted. The full parametrisation of the model enables automatic initiation of the simulation upon reading an input file containing key variables. Furthermore, this allows the calculation to be adopted to different process parameters in an efficient manner. The validation was conducted using experimentally temperature measurements obtained from welds between EN AW-1050A-H14 and EN CW024A-R240, with the simulation showing only minor deviations from the experimental data. Subsequently, the specimens were analysed by scanning electron microscopy, and the thickness of the intermetallic layer was characterised for different process parameters, ranging from 84 ± 28nm to 309 ± 56 nm. Furthermore, higher temperatures were shown to increase both intermetallic layer thickness and ultimate lap shear force, however, the correlation with the latter is only valid under limited heat input conditions. |
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Detection of Micro- and Nanoplastic (MNP) in winter wheat plants
Ilja Ortner
Abstract: Ilja Ortner (1), Rene Markolin (1), Thomas Rath (3), Julian Drausinger (4), Christian Pichler-Rohrhofer (5), Johannes Rattenberger (1,2)
1. Institute of Electron Microscopy and Nanoanalysis (FELMI), Graz University of Technology, Steyrergasse 17, 8010 Graz, Austria
2. Graz Centre for Electron Microscopy (ZFE), Steyrergasse 17, 8010 Graz, Austria
3. Institute for Chemistry and Technology of Materials, Graz University of Technology, Stremayrgasse 9, 8010, Graz, Austria
4. Lebensmittelversuchsanstalt (LVA), Zaunergasse 1-3, 1030 Wien, Austria
5. Versuchsanstalt für Getreideverarbeitung (VG), Prinz-Eugen-Strasse 14, 1040 Wien, Austria
Introduction
Micro- and nanoplastics, ranging from 1 nm to 5 mm in size, are among the most discussed pollutants in our society. This is hardly surprising, given that the weekly human consumption can be as high as 5 g - which is equivalent to the weight of a credit card. [1] However, the exact intake pathways are not yet fully understood and remain subject of current research.
The ACR-strategic project MicroPIC (Microscopy For Plastics In Cereals) is dedicated to the controlled contamination and observation of MNP in winter wheat by using a variety of vibrational spectroscopy analyses (FT-IR and Raman spectroscopy) and electron microscopic (EM) methods (SEM, TEM).
Methods
A routine for the controlled contamination of winter wheat plants during germination and growth with Polystyrene (PS) MNP was formulated. Since most spectroscopic methods are deficient in the required resolution needed for such observations and due to the weak contrast for organic specimens in EM, the introduced PS-MNP were labelled with gold NP for contrast enhancement.
At various growth stages different plant parts (root, seedling, shoots) were analyzed for micro- and nano plastic deposits.
Results and outlook
Paired with different sample preparation approaches (microtomy, ion beam slope cutting) the observation of the presence and position of MNP clusters in winter wheat roots and shoots was feasible with low vacuum scanning electron microscopy (LV-SEM) in conjunction with energy-dispersive X-ray spectroscopy (EDX).
However, to what extent MNP impact the quality of winter wheat and whether MNP will also find its way into the grain of corn needs to be discovered through follow-up research
References
[1] Gruber et al., Expo Health 15, 33–51 (2023)
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Ongoing Master´s Theses at IBioSys
Ines Gaberscek, Bilge Keles, Anja Ralón Rosales, Aleksandr Zolotov, Rupert Kargl, Karin Stana Kleinschek, Institute of Chemistry and Technology of Biobased Systems (IBioSys)
Abstract:
1) Ines Gaberscek: Bioresponsive polysaccharide hydrogels.
Chemical modification of polysaccharides with appropriate reactive functionalities enables crosslinking under physiological conditions using peptide-based linker molecules. By selecting specific peptide motifs, the bioactivity of the resulting hydrogels can be precisely tailored, for example to promote cell adhesion or to enable enzyme-mediated, controlled biodegradation. The overarching objective is to develop polysaccharide–peptide hydrogel bioinks suitable for the 3D-printing and tissue culture of biologically relevant constructs exploiting and controlling the reactivity of thiols and thioesters.
2) Bilge Keles: Chemical and biological modification of bacterial cellulose.
Bacterial cellulose (BC) is a renewable, natural material produced extracellularly by various microorganisms and is known for its high purity, excellent water-holding capacity, strong mechanical properties, and complex three-dimensional nanofibrillar structure. BC can be modified to introduce new properties into its network either through post-synthetic chemical modification or during fermentation by feeding different carbon sources. Tuning the properties of BC in this way offers new possibilities for biomaterial platforms in 3D-printing applications. This master’s thesis is performed in collaboration with Assoc. Prof. Dr. Regina Kratzer and co-workers from the Institute of Biotechnology and Biochemical Engineering (BIOTE) at TU Graz.
3) Anja Ralón Rosales: Polysaccharides for core-shell 3D-printing.
Different polysaccharides, including alginate and carboxymethyl cellulose can be chemically modified with peptides and cross-linked by enzymes. The resulting polymers can be extruded into tubular core-shell structures, which can serve as nerve guidance conduits (NGCs) to regenerate damaged peripheral nerves. This master’s thesis is performed in collaboration with Assist. Prof. Dr. Theresa Rienmüller and co-workers from the Institute of Biomechanics (BIOMECH) at TU Graz and Dr. Raimund Winter from the Plastic, Aesthetic and Reconstructive Surgery Department of the Medical University of Graz.
4) Aleksandr Zolotov: Preparation of Cellulose Nanostructures.
Homogenization is one of the methods for producing nanofibrillated cellulose (NFC). However, using pulp directly has limitations, as bulky cellulose fibers can clog narrow parts of the equipment. To prevent malfunction, pretreatment methods such as pulp beating, enzymatic treatment, and others, are used to reduce fiber size. This thesis investigates how different pretreatment methods and homogenization parameters affect NFC quality and attempts to establish an optimal, combined strategy for production of NFC with desired properties. Chemical modification of NFC post-homogenization is envisaged in collaboration with the Glycogroup of IBioSys. This master’s thesis is performed in collaboration with Univ. Prof. Dr. Ulrich Hirn and co-workers from the Institute of Bioproducts and Paper Technology (BPTI) at TU Graz and Univ. Prof. Dr. Tanja Wrodnigg and co-workers from the IBioSys Glycogroup.
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Challenges of Probing Cation Diffusion in Mixed Ionic-Electronic Conductors
J. Mutscher, H.M.R. Wilkening and B. Gadermaier, Institute for Chemistry and Technology of Materials
Abstract: Mixed ionic-electronic conductors (MIECs) enable transport of cations and electrons within a single crystalline phase, raising a fundamental question: are these mechanisms coupled? Ionic conduction typically occurs via site-to-site hopping, while electronic conduction relies on redox hopping between transition metals. Conductivity measurements do not naturally distinguish between ionic and electronic transport, hence selectively modifying cationic and electronic conduction via crystal chemical engineering could help answer this question. Since partial aliovalent substitution of neither alkali nor transition metal in alkali hexatitanates proved successful we turned to using galvanostatic intermittent titration (GITT) to study cation diffusion. As GITT relies on alkali ion insertion alongside transition metal reduction, ionic mobility may be studied as a function of the exact composition, but experimental conditions strongly influenced the results, highlighting the need for robust protocols. |
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Data-Driven Polyoxometalate and Reticular Chemistry
Jan Leodolter, Aleksandar Kondinski
Abstract: Polyoxometalates (POMs) and reticular architectures span a large and diverse chemical space. A practical bottleneck is how information is recorded, connected, and reused across studies. Relevant data such as structures, synthesis conditions, characterisation, and computed models are often scattered across formats and thus, difficult to compare or process at scale.
In this poster, we present selected examples from a data-driven workflow for POM and reticular chemistry that connects data curation, structured representation, automated structure construction, and database storage. The workflow organises heterogeneous records into a consistent schema linking composition and connectivity with descriptors and provenance. It supports batch processing and systematic comparison across candidate sets. We also show selected examples of automated routines to construct and geometry optimise cage and polyhedral architectures from defined building units, producing comparable structures and outputs. The resulting database and scripts enable efficient rebuilding, checking, and screening of structures and provide a practical basis for reproducible and extensible exploration. |
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Ion-conductive papers -Influence of fiber processing
Janis Zoder, Institute of Bioproducts and Paper Technology (BPTI)
Abstract: A recent application for paper-based composites is their use as ion-selective membrane in fuel cells and redox flow batteries [1]. In contrast to the perfluorinated ion exchange membranes currently in widespread use, cellulose-based membranes do not contain any harmful halogens and are therefore more environmentally friendly and more easily biodegradable.
However, these ionically conductive modified papers still exhibit the disadvantages of lower ion selectivity and ionic conductivity and, above all, cross-diffusion.
Here we investigate the influence on these parameters on varying the properties of the fiber content of this composite material. To compete with current market leaders, bio-based membranes must first show a comparable level of cross-diffusion between the two electrolytes of the flow battery system. For numerical comparison, a (cross) diffusion test with an electrolyte-like substance provides information. Initial diffusion tests with unrefined, long-fiber 80 g/m² laboratory sheets show that pulp refinement reduces cross-diffusion by 26%. Increasing the basis weight by 20 g/m² at the same degree of refining leads to a reduction in diffusion by a factor of 2.
We evaluated the influence of basic papermaking parameters such as fiber type, refining energy, basis weight, hydrophobicity, and wet strength on membrane performance. We tested cross-diffusion, electrochemical impedance, battery lifetime, and battery performance. The results help understand how fiber processing and fiber network affects the ion transport and electrochemical properties of the final membrane composite material.
[1] Lander, S., Vagin, M., Gueskine, V., Erlandsson, J., Boissard, Y., Korhonen, L., Berggren, M., Wågberg, L. and Crispin, X. (2022), Sulfonated Cellulose Membranes Improve the Stability of Aqueous Organic Redox Flow Batteries. Adv. Energy Sustainability Res., 3 : 2200016.
https://doi.org/10.1002/aesr.202200016
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Copolymerization of epoxyeugenol and bisphenol A diglycidyl ether
Johanna Lang, Johanna M. Uher, Susanne, M. Fischer, Christian Slugovc, ICTM
Abstract: Eugenol is a liquid phenolic compound accessible from renewable resources such as clove or cinnamon, by lignin degradation or by chemical synthesis[1]. Many monomers and their corresponding polymers have been prepared from eugenol[2]. Here, we perform the epoxidation of the double bond to obtain the corresponding liquid epoxide, namely 2-methoxy-4-(oxiran-2-ylmethyl)phenol
(epoxyeugenol, EE) in a single step, and test this monomer in the copolymerization with bisphenol A diglycidyl ether (DGEBA). In particular, we studied the polymerization reaction with 1-methylimidazol (1- MI) and Tris-2,4,6-dimethylaminomethyl phenol (K54) as initiators using isothermal and dynamic differential scanning calorimetry (DSC) to determine activation energies based on the Kissinger method[3] for different formulations.[4]
[1] Zhang C., Xue J., Yang X., Ke Y., Ou R., Wang Y., Madbouly S. A., Wang Q. Prog. Polym. Sci. 2022, 125, 101473.
[2] Morales-Cerrada R. Molina-Gutierrez S., Lacroix-Desmazes P., Caillol S. Biomacromolecules 2021, 22, 3625–3648.
[3] Lascano D., Quiles-Carrillo L., Balart R., Boronat T., Montanes N. Polymers 2009, 11, 391.
[4] Lang, J., Uher, J.M., Fischer, S.M. et al. Monatsh. Chem. 2025. doi.org/10.1007/s00706-025-03331-7 |
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Fluorescent Coumarin-Based Markers for Polyolefin Identification
Johanna Uher, PCCL
Abstract: Advancing towards a circular economy that maintains plastics in their highest-value state is essential to mitigate environmental impacts and promote recycling, reuse, and reduction. Despite the ubiquitous relevance of recycling, significant challenges remain, including the detection of microplastics and the accurate classification of polymer recycling qualities. Identifying opaque polymers and producing recyclates with properties comparable to virgin materials is difficult, as the thermal history of polymers is often unknown.[1]Current used functional markers in the recycling industry frequently suffer from migration due to the lack of covalent attachment to the polymer matrix. Consequently, recycled plastics containing such markers are rarely approved for food packaging, as dye migration and contamination cannot be ruled out.[2] This project focuses on the synthesis of fluorescent coumarin-based dyes [3], which are modified to introduce functional groups enabling covalent attachment to polymers through various grafting techniques. These include free radical grafting, plasma grafting combined with silanization. Such methods are scalable and compatible with industrial processing, as they can be applied under elevated temperatures or pressures without requiring polymer dissolution. |
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Ultra-Broadband Optical Property Characterization with Dual-Comb Spectroscopy
Johannes Spendier
Abstract: Dual-comb spectroscopy (DCS) is well established for high-resolution absorption measurements, particularly in gas-phase spectroscopy. Its core principle relies on multi-heterodyne beating between two optical frequency combs with slightly detuned repetition rates, enabling a coherent down-conversion of optical frequencies into the radio-frequency domain. This process allows broadband, phase-resolved spectra to be acquired without moving components.
Beyond absorption, the phase information retrieved from the beat signals provides direct access to dispersion, refractive index and non-linear properties of any material, including gasses, liquids or solids. In this work, we demonstrate a DCS-based platform for solid and liquid samples that require only partial transmission and reflectance, ensuring high versatility of the technique (e.g. various types of glasses including fibers, liquid samples etc.)
While current measurements are performed across a limited spectral range (10 nm, centered at 1050 nm), the system architecture is currently expanded towards ultra-broadband operation covering more than 400 nm. Supercontinuum generation in photonic crystal fibers provides a clear pathway to overcoming the bandwidth limitations of laser sources. This approach positions DCS as a versatile tool for phase-sensitive optical property characterization across a wide range of liquids and solid samples such as novel materials for solar and photovoltaic energy harvesting including III–V semiconductors, organic semiconductors or perovskites.
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Improved Photostability and Burn-In Suppression in Organic Solar Cells Using a PEDOT:PSS/2PACz Hole Transport Bilayer
Julia Hönigsberger, Institute for Chemistry and Technology of Materials, Graz University of Technology
Abstract: In recent years, the power conversion efficiencies of organic solar cells have improved significantly. However, typically a pronounced performance loss occurs in the initial operating hours, the so-called burn-in. This effect is often attributed to unstable active layer morphologies. In contrast, our work demonstrates that a tailored hole transport layer (HTL) can significantly enhance the photo-stability and suppress the initial burn-in in PM6:Y6 bulk heterojunction organic solar cells.
In the first step, we investigated several hole transport materials, including PEDOT:PSS 4083, PEDOT:PSS pH-neutral, 2PACz, and bilayer modifications. Although the drawbacks of PEDOT:PSS are widely discussed in the organic solar cell community, the material is still the choice in highly efficient organic solar cells. We tested a pH-neutral PEDOT:PSS alternative, but the alternative could not achieve comparable efficiencies and long-term stability. Therefore, we turned the focus of our research to the self-assembling molecule (2-(9H-carbazol-9-yl)ethyl)phosphonic acid (2PACz). While we found that 2PACz as HTL suffers from severe photo instability, the solar cells with the PEDOT:PSS 4083/2PACz bilayer HTL showed remarkable storage stability in continuous illumination over 650 h without any observable burn-in.
To elucidate the underlying degradation mechanisms, we performed transient photovoltage measurements. These revealed that the superior photostability of devices employing the bilayer HTL originates from less interfacial disorder induced during the photo-aging process.
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Title: Determining Critical Electrochemical Parameters to Improve Plating Uniformity for Large Scale Substrates.
Julia Karitnig, Lam Research
Abstract: Controlling non-uniformity in electrodeposition is essential for consistent, high-quality electroplating. As substrate sizes grow to 750×610 mm and microelectronics continue to miniaturize, achieving superior copper plating uniformity becomes increasingly critical. Large substrates are processed in vertical chambers, where enhancing plating and within-die uniformity is a major challenge. Addressing this requires a combined approach of experimental measurements and advanced numerical simulations. A reproducible method is developed using a rotating disk electrode and a Mini-Cell apparatus to accurately measure electrochemical key parameters. By integrating the Mini-Cell with a digital twin, the impact of various factors on within-die uniformity is analyzed, enabling optimization for high-quality deposition. This approach supports the growing demand for uniform micro- and nanoelectronics on large substrates. |
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Defects in Glass-to-Metal Bonds of Hermetic Electric Terminals
Julia Puntigam, Institute of Materials Science, Joining and Forming
Abstract: Electric connectors are of fundamental importance for the long-term impermeability of hermetic seals. These connectors, made from glass and metal, function as electric terminals, guaranteeing power supply to the vessel’s interior while ensuring a gas-tight enclosure. However, glass to metal bonding presents challenges because of dissimilar material characteristics, such as different melting temperatures, thermal expansion, and ductility. Time consuming, non-destructive tests (He-leak tests) in the manufacturing line expose a certain batch-dependent failure rate in a late stage of production. This study aims to investigate the root cause of the defects in the joint area of hermetic seals to optimize the production process and minimize waste. Separately, we inspected the quality of the incoming hermetic seal and its alteration during production. Micro-computed tomography tests reveal spherical cavities in the glass body and cracks along the glass-metal interface. During installation and subsequent assembly, significant temperature differences caused by the welding processes lead to thermal strain in the geometry close to the seal, causing crack initiation or growth in the glass body. Temperature measurements during the welding process quantify the acting thermal gradient. These data are used to validate a FEM model (Simufact Welding) which can subsequently aid in the welding procedure to minimize the load on the glass-metal interface. Based on the gained knowledge process optimizations preventing defects in the electrical terminals of hermetic seals ensure high quality and long-lasting products. |
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Unraveling overlapping processes in the sorption and in the release dynamics of DMSO vapor in paper
Karin Zojer
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Germanium-based IniSwitches: Towards New Photoresponsive Materials
Konstantin Knaipp, Institute of Physical and Theoretical Chemistry
Abstract: Radical polymerization reactions can be induced with light by employing a photoinitiator. Acylgermanes have been established as efficient photoinitators across a wide range of wavelengths.[1] Recently it has been demonstrated that acylgermanes can be conjugated onto surfaces, anchoring the growing polymer chain and enabling facile access to functionalized surfaces.[2] Molecular photoswitches are compounds that can be “switched” between different states depending on the wavelength of illumination. One such molecule is azobenzene, which can be reversibly photoisomerized between its cis and trans isomer. Conjugating azobenzene to polymers gives access to materials that can undergo reversible phase changes when illuminated at different wavelengths, which has potential applications in the field of energy storage.[3]
In this study we present the first investigations on acylgermane-based IniSwitches; compounds that combine a photoinitiating acylgermane moiety and a photoswitching azobenzene moiety. We show possible synthetic pathways, investigate photochemical behavior and explore how this novel class of compounds gives access to photoswitchable polymer materials.
References:
[1] Radebner, J.; Eibel, A.; Leypold, M.; Gorsche, C.; Schuh, L.; Fischer, R.; Torvisco, A.; Neshchadin, D.; Geier, R.; Moszner, N.; et al. Angew Chem Int Ed Engl 2017, 56 (11), 3103-3107. DOI: 10.1002/anie.201611686.
[2] Muller, M.; Drusgala, M.; Fischer, R. C.; Torvisco, A.; Kern, W.; Haas, M.; Bandl, C. ACS Appl Mater Interfaces 2023, 15 (26), 31836-31848. DOI: 10.1021/acsami.3c05528.
[3] Imato, K.; Kaneda, N.; Ooyama, Y. Polymer Journal 2024, 56 (4), 269-282. DOI: 10.1038/s41428-023-00873-7.
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Deformation and strain measurements at high frequencies us-ing digital image correlation
Kriti Batra, Institute for Chemistry and Technology of Materials, Graz University of Technology, 8010 Graz, Austria
Abstract: Understanding the mechanical response of materials requires reliable experimental techniques, capable of capturing deformation and strain under different loading conditions, which are essential for deriving fundamental stress–strain curves. Traditional instrumentations, such as strain gauges, linear variable differential transformers, and extensometers, typically yield point-wise or averaged values that are taken to represent the overall macroscopic behavior of the specimen.
Progress in digital imaging technologies has led to significant improvements in the digital image correlation (DIC) technique, enabling the measurement of two- and three-dimensional displacement fields on material surfaces [1]. By tracking the displacement of a random speckle pattern on the specimen surface with digital cameras, DIC allows direct computation of displacement, strain, strain rate, velocity, and curvature. Because it is a non-contact method, its performance is independent of both material type and specimen size, making it particularly suitable for complex geometries and heterogeneous materials. Compared with conventional approaches, DIC provides spatially resolved data that offer a significantly deeper insight into material behavior.
In this study, the DIC technique is extended beyond its conventional application in quasi-static deformation measurements under slowly varying external loads and adapted for displacement and strain analysis under high-frequency excitation, particularly at mechanical resonance [2]. Such conditions are highly relevant for piezoceramic materials, which are extensively employed in applica-tions including ultrasonic medical imaging, welding, and cleaning. At resonance, these systems typically exhibit displacement amplitudes ranging from 0.1 to 10 µm at frequencies exceeding 30 kHz [3]. The developed DIC system enables the measurement of deformation, strain, and localized strain concentrations in polymeric, metallic, and ceramic specimens of varying geometries and dimensions, spanning regimes from quasi-static to high-frequency loading. This capability provides a powerful tool for identifying fundamental material properties, as well as critical defects arising from material behavior or design limitations.
References:
[1] H. Schreier, Image Correlation for Shape, Motion and Deformation Measurements, Springer US, Boston, MA, 2009.
[2] T.N. Nguyen, et al., J. Mater. Res. 36 (2021) 996-1014.
[3] K. Uchino, High-Power Piezoelectrics and Loss Mechanisms, CRC Press, 2020.
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Alcohols in Lewis-base catalysed polyaddition reactions: The case of aliphatic isocyanates
Lena M. Hofbauer, Susanne M. Fischer, Christian Slugovc (ICTM)
Abstract: While the use of aliphatic alcohols as monomers in polyaddition reactions such as ring opening of epoxides or Michael chemistry is rather underdeveloped, alcohols are often used in the reaction with isocyanates to form poly(urethanes). For room temperature curing of aliphatic isocyanates, tin-based catalysis is still the state of the art. However, the development of fast curing tin-free formulations is an important goal for the practical application of this chemistry.1
In this contribution we present our results on Lewis base catalysis for the reaction of aliphatic isocyanates with alcohols at room temperature. Emphasis is placed on uncovering the role of the electronic properties of the alcohol on the rate of the reaction using different Lewis bases and dibutylin dilaureate (DBTL) as a reference catalyst. The results showed that none of the Lewis bases could compete with DBTL in catalytic activity. However, a strong dependence of the reaction rate on the acidity of the alcohol was found. More acidic alcohols (e.g. propargyl alcohol) react much faster than less acidic ones (e.g. propanol). This phenomenon is much less pronounced when DBTL is used as the catalyst.
Finally, we compare the reactivity of the alcohols in isocyanate chemistry with their reactivity with other electrohiles, namely epoxides and some Michael acceptors, and find different dependencies of the alcohols acidity on the reaction rate.2
References:
1 Sardon, H.; Pascual, A.; Mecerreyes, D.; Taton, D.; Cramail, H.; Hedrick, J. L. Macromolecules 2015, 48, 3153. DOI: 10.1021/acs.macromol.5b00384
2 Fischer, S. M.; Kaschnitz, P.; Slugovc, C. Catal. Sci. Technol. 2022, 12, 6204. DOI: 10.1039/D2CY01335E
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Hydrogen Embrittlement and uptake of AISI 304 stainless steel bar by electrochemical charging in SSRT
Leonhard Georg Grünwalder
https://cloud.tugraz.at/index.php/s/maHbBHLXZof9rzo
Abstract: Austenitic stainless steel AISI 304 (X5CrNi18-10 / 1.4301) is widely used in the food industry, construction and automotive applications and is a candidate material for components in future hydrogen technologies. In such environments, cathodic protection or electrochemical reactions can introduce hydrogen and potentially cause hydrogen embrittlement (HE). The aim of this study is to examine metastable AISI 304's sensitivity to hydrogen absorption and hydrogen-induced embrittlement under industrial service circumstances. Standard tensile tests and slow strain-rate tests were performed on uncharged specimens and specimens treated to either in-situ electrochemical charging during testing or gaseous pre-charging. Hydrogen contents were quantified by thermal desorption analysis, while fracture surfaces and microstructural changes (including deformation-induced martensite) were examined by fractography and complementary metallographic methods.
Electrochemical in-situ charging caused a pronounced loss in ductility, with fracture elongation reduced to less than half of the uncharged reference sample, whereas the ultimate tensile strength was only moderately affected. Fracture surfaces showed a mixed, predominantly intergranular fracture mode and microstructural analyses revealed localized deformation-induced martensite near the fracture zone. In contrast, gaseous pre-charging under the applied conditions produced no measurable embrittlement. The results demonstrate that AISI 304 can become significantly embrittled when exposed to hydrogen under electrochemical charging and simultaneous mechanical loading, highlighting the need for careful assessment of this steel in hydrogen-rich industrial environments. |
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Monosilane as a Cheap Feedstock for Branched Oligohydridosilanes
Madeleine Heurix, Institute of Inorganic Chemistry
Abstract: Recently, liquid phase deposition (LPD) attracted attention, due to its reduced production costs as compared to standard vacuum-based approaches. In this context, oligohydridosilanes such as compounds 1 (Figure 1) are ideal precursors and decompose to elemental silicon upon heating to T > 300 °C[1]. However, the high production cost of compound 1, prevented its implementation as industrial precursors, so far. Therefore, this study was aimed to investigate possible synthetic routes, starting with a cheaper feedstock, to higher silicon hydrides SinH2n+2. The method of Sundermeyer et al. and Fehér at al. was revisited where monosilane is used to generate potassiumsilanide 2 and further potassiumisotetrasilanide 3[2]. The generation of com-pound 3 enabled the selective generation of compound 4 and 5 which are oligohydridosilanes (Figure 2).
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EU - GreenOMorph - Sustainable Materials Design and Synthesis for Organic Electronic Devices
Magdalena Steinbrugger, Jakob Keler, Danijel Babic, Suman Mallick, Thomas Rath, Gregor Trimmel, Institute for Chemistry and Technology of Materials
Abstract: The environmental impact of electronic materials and their processing represents a major challenge for future device technologies. Within the GreenOMorph project, TU Graz contributes to the development of sustainable functional organic materials by integrating molecular design, synthesis, and processing strategies while maintaining performance and processability required for electronic and sensing applications.
One research focus addresses the design of non-fluorinated, bio-derived piezoactive materials for printed ferroelectric sensors, where amino acids and peptides are explored as sustainable building blocks. Initial molecular designs toward alkyne-functionalized peptide systems have been established to enable further assembly and processing strategies.
Small-molecule organic semiconductors are investigated using modified and more sustainable synthetic approaches. P-type semiconductors based on thienoacene cores such as BTBT are synthesized using greener solvent systems and alternative reaction environments to access functionalized derivatives. In parallel, n-type organic semiconductors based on non-fused architectures are explored, where molecular planarity and efficient pi–pi stacking are achieved through bulky side groups and non-covalent conformational locking motifs, with end-group variations evaluated using DFT calculations.
In addition, more sustainable synthetic pathways toward organic mixed ionic–electronic conductors for organic electrochemical transistors are assessed, focusing on the replacement of hazardous reagents and solvents in benchmark polymer systems. Together, these activities highlight a materials-oriented approach within GreenOMorph, addressing sustainability across different organic material classes relevant to future electronic and sensing devices.
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Design Principles for Biomaterials in 3D Cell Cultures
Mathias Polz, Theresa Rienmüller, Manuel Kainz, Tamilselvan Mohan, Rupert Kargl, Karin Stana Kleinschek, Julia Fuchs, Institute of Biomechanics
Abstract: The design of biomaterials for 3D cell culture plays a critical role in regulating cell behavior, function, and fate. Rather than having fixed, static requirements, cells continuously sense and respond to dynamic changes in their microenvironment through structural, mechanical, and chemical pathways. These time-dependent properties of the in vivo environment strongly influence the physiological accuracy and biological relevance of advanced 3D cell culture systems. Structural features such as architecture and confinement affect cell organization and tissue formation, while mechanical properties - including stiffness and the (time-dependent) viscoelastic behavior - predominantly modulate processes such as migration, proliferation, and differentiation. In parallel, chemical characteristics such as surface chemistry, wettability, and bioactive signaling govern protein adsorption and cell-material interactions and subsequent force transmission. This overview poster highlights that different cell types require distinct and dynamically evolving combinations of these cues, underscoring the importance of adaptable and context-dependent biomaterial design.
Such insights are particularly critical for the development of physiologically relevant 3D cultures, artificial matrix and bioink development and 3D bioprinting strategies, where spatial and temporal control over material properties is essential for recreating functional tissue-like environments. |
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Polystyrene as a Platform for Heterogeneous (Photo-)Catalysis
Max Schmallegger, Institute of Physical and Theoretical Chemistry
Abstract: Polystyrene synthesized via photochemical methods serves as an effective and versatile platform for the incorporation and stabilization of catalytically active species. We present two distinct methodologies for the preparation of polymer-immobilized heterogeneous catalysts: First, we demonstrate the straightforward preparation of an AlCl3/polystyrene composite, which functions as an easily accessible catalyst for the solvent-free synthesis of aryl-substituted tetrazoles and facilitates a simple work-up procedure.
Additionally, we present a photocatalyst in which thioxanthone is covalently attached to a polystyrene polymer(TX-at-PS). This TX-at-PS can photocatalytically oxidize alcohols to aldehydes upon LED irradiation (405 nm) via a singlet oxygen pathway. Utilizing this catalyst yields results comparable to those of similar systems and allows for convenient isolation of the products. |
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Xanthates: Powerful single-source precursors for highly porous metal sulfides
Melissa Egger, ICTM
Abstract: In heterogeneous (photo)catalysis, the efficiency depends on a great number of factors: bandgap and alignment, absorption coefficient, catalyst stability, and more. Many of the required properties for an efficient catalyst can be found in metal sulfides, such as ZnIn$_2$S$_4$[1], CuInS$_2$[2], Cu$_3$BiS$_3$[3], CuSbS$_2$, Cu$_1$$_2$Sb$_4$S$_1$$_3$[4] and AgBiS$_2$[5]. Those materials show bandgaps in the lower visible range and have high absorption coefficients above 105 cm-1. However, the activity of heterogeneous catalysts is limited by the surface area of the catalyst. To address this issue, we prepared different metal sulfides from metal xanthate single-source precursors. These metal xanthates provide both the metal and sulfur source, and the thermal decomposition to metal sulfides forms micro- or mesopores in the process. Varying the xanthate’s side chain offers control over solubility, conversion temperature and porosity.[6] Metal sulfides can not only be used as photocatalysts by themselves. They can also be applied as cocatalysts to increase the activity of other photocatalysts, such as the well-known cheap, abundant, and non-toxic photocatalyst titania.[7] We prepared mesoporous titania films and infiltrated them with metal xanthate solutions, which were thermally converted to the metal sulfides. We used the pristine porous sulfides and the sulfide@mpTiO$_2$ for dye degradation and hydrogen evolution experiments.
[1] M. Sigl, M. Egger, F. Warchomicka, D. Knez, M. Dienstleder, H. Amenitsch, G. Trimmel, T. Rath, J. Mater. Chem. A 2024, 12, 28965.
[2] E. Vakalopoulou, T. Rath, F. G. Warchomicka, F. Carraro, P. Falcaro, H. Amenitsch, G. Trimmel, Mater. Adv. 2022, 3, 2884.
[3] T. Rath, J. M. Marin-Beloqui, X. Bai, A.-C. Knall, M. Sigl, F. G. Warchomicka, T. Griesser, H. Amenitsch, S. A. Haque, ACS Appl. Mater. Interfaces 2023, 15, 41624.
[4] T. Rath, A. J. MacLachlan, M. D. Brown, S. A. Haque, J. Mater. Chem. A. 2015, 3, 24155.
[5] E. Vakalopoulou, D. Knez, M. Sigl, G. Kothleitner, G. Trimmel, T. Rath, ChemNanoMat 2023, 9, e202200414.
[6] E. Vakalopoulou, T. Rath, M. Kräuter, A. Torvisco, R. C. Fischer, B. Kunert, R. Resel, H. Schröttner, A. M. Cocli-te, H. Amenitsch et al., ACS Appl. Nano Mater. 2022, 5, 1508.
[7] Zhang, L. et al., Int. J. Hydrogen Energy 2012, 37, 17060–17067.
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Mechanochemical Synthesis of Hydrogen-Bonded Organic Framework Enzyme Biocomposites for Biocatalysis
Miriam Zeller
Abstract: Hydrogen-bonded organic frameworks are an emerging class of porous materials with broad applicability in the fields of sensing, catalysis and biocatalysis.[1] They are composed of organic molecules (linkers) with an aromatic core and various functional groups that can form hydrogen bonds. Through the geometry of the organic linkers, $\pi$-$\pi$ stacking of the aromatic part thereof and the directionality of the hydrogen bonds, 3-D porous networks can be assembled. A few HOFs can be synthetize in biocompatible conditions (i.e. aqueous solution, room temperature) and in presence of enzymes, leading to the formation of enzyme$@$HOF biocomposites.[2-4] Their accessible porosity, broad stability across pH ranges and solvents, and ability to stabilize encapsulated enzymes make these biocomposites valuable materials for biocatalysis.[2-4]
Despite the promising performances of these biocatalysts, recent studies suggest that most immobilized enzymes reside on or near the surface of HOF crystals, which may reduce the protection afforded to them, for example by increasing their exposure to proteolytic agents such as proteases.[4] However, in aqueous syntheses, the rapid crystallization of HOFs prevents precise control over crystal growth and enzyme spatial distribution.[2]
Our group applied mechanochemistry to control the growth and crystallisation of HOF biocomposites.[5] Through this novel approach we could obtain enzyme$@$HOF biocomposites with a more homogeneous distribution of the enzyme throughout the bulk of the HOF particles, higher protection towards proteolytic agents and higher retained enzymatic activity compared to the samples synthetized via conventional solution methods. Currently, we are expanding the scope of this innovative synthetic approach to include a range of HOFs that cannot be synthesized as biocomposites using standard solution-based methods. In conclusion, this research opens up new possibilities of combining HOFs with enzymes with a novel mechanochemistry-based synthetic approach to synthesise biocomposites with catalytic properties.
[1] Z.-J. Lin, et al., ACS Cent. Sci., 2022, 8, 1589–1608.
[2] W. Liang, et al., J. Am. Chem. Soc., 2019, 141, 14298–14305.
[3] P. Wied, et al., Angewandte Chemie International Edition, 61, e202117345.
[4] F. Carraro, et al., Small, 2024, 2407487.
[5] M. R. Hafner, et al., Small, 2025, 21, 2504744. |
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Elucidating energy dissipation on 2D materials: Surface dynamics on h-BN and graphene
Noah J. Hourigan, Philipp Seiler, Boyao Liu, Jack Kelsall, Alv J. Skarpeid, Håkon I. Røst and Anton Tamtögl
Abstract: While graphene and molecule-graphene interactions have been widely studied, hexagonalboron nitride (h-BN) remains less understood despite its structural similarity to graphene. h-BN's slightly polar B-N bonds impart a large band gap, high thermal conductivity, and chemical stability, making it promising for electronics and coatings. Understanding energy dissipation and how molecules interact with h-BN is therefore essential for advancing its integration into functional interfaces and nanoscale systems [1].
Building on our prior work on bilayer graphene [2], we show that intercalation effectively decouples h-BN from a Ni(111) substrate, creating a quasi-free-standing layer. This decoupling significantly alters the electron-phonon coupling ($\lambda$), providing insight into energy dissipation mechanisms. We also probe the nanoscale motion of single molecules on h-BN/Ni, where both H$_2$O and benzene reveal a lower diffusion barrier compared to graphene/Ni - despite the structural similarity of both surfaces. Using helium spin-echo and ab initio methods, we find that e.g. water on h-BN/Ni exhibits lower activation energies and enhanced rotational-translational coupling compared to graphene/Ni, pointing to distinct mobility regimes shaped by interactions with the supporting substrate which is further confirmed by atomic-scale friction calculations [3]. Together, these results underscore the unique dynamic landscape of weakly interacting molecules on polar 2D materials [4,5].
[1] A. J. R. Payne, N. F. Xavier Jr, A. Tamtögl, M. Sacchi. small 21, 2405404 (2025).
[2] N. J. Hourigan, P. Seiler, M. Wetherington, C. Dong, J. A. Robinson, G. Benedek, A. Tamtögl. Carbon 238, 120156 (2025).
[3] P. Seiler, A. Payne, N. F. Xavier Jr, L. Slocombe, M. Sacchi, A. Tamtögl. Nat. Commun. 16, 10465 (2025).
[4] M Sacchi, A Tamtögl. Adv. Phys. X 8, 2134051 (2023).
[5] A Tamtögl, M Sacchi. Nanoscale Horiz. 10, 3158 (2025).
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RRDE Characterization of new PEM Cathode Catalysts for H2O2 Production
Nuša Perko, HyCentA
Abstract: Hydrogen peroxide (H2O2) ranks in the list of top 50 most important chemical compounds in the world, as its production exceeds over four million tons per year. Industrial H2O2 is predominantly produced via the anthraquinone process, consisting of hydrogenation, oxidation, and extraction/distillation steps. This route requires Pd-based catalysts, organic solvents and elevated temperatures (> 100 deg C) and relies on centralized production. The product must be transported either in diluted form, which increases transport volumes and costs, or at higher concentrations, which entails stringent safety measures due to the inherent instability and oxidative reactivity of H2O2. An alternative approach is the decentralized electrochemical production of H2O2 via different routes, such as electrolysis and polymer electrolyte membrane (PEM) fuel cells. PEM fuel cells enable compact, on-site generation that can be coupled to green hydrogen. In the electrochemical oxygen reduction reaction (ORR), oxygen can be reduced either via a four-electron pathway (4e- ORR) to water, which is thermodynamically favored and dominant in conventional fuel cells, or via a two-electron pathway (2e- ORR) to hydrogen peroxide, which is kinetically more demanding. Consequently, the key challenge under PEM conditions is to achieve high selectivity for the 2e- ORR by employing atypical catalysts that suppress the competing 4e- pathway and avoid catalytic H2O2 decomposition. In this work, we evaluate two novel cathode catalyst systems designed for selective 2e- ORR: nitrogen-doped carbon (N-C) and cobalt tetraphenyl porphyrin supported on carbon (CoTPP/C). Both materials are benchmarked against Pt/C under controlled electrochemical conditions in 0.1 M HClO4 to assess activity and selectivity. Catalyst performance is characterized using the rotating ring-disk electrode (RRDE) method. The selectivity and electron transfer numbers were quantified using the disk and ring currents at 1600 rpm over the range 0.8-0.5 V. The N-C catalyst exhibited an average electron transfer number of n = 3.20 with 35% H2O2 yield, while CoTPP/C showed n = 3.11 with 36% H2O2 yield. These results indicate the enhancement of the 2e- ORR pathway and support the use of N-C and CoTPP/C as materials for follow-up optimization of cathode layers in PEM fuel cells. |
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Magnetometry Studies of Prussian Blue Analogues in Sodium-Ion Batteries: Study of Degradation Pathways and the Electrochemical Behavior
Olzhas Kaupbay, Institute for Chemistry and Technology of Materials
Abstract: Prussian Blue analogues (PBAs) attract significant interest as cathode materials for sodium-ion batteries, due to their good electrochemical performance and sustainability. Their open crystalline framework enables reversible insertion of large ions such as $Na^+$ with minimal lattice strain and fast diffusion.However, the high reactivity toward oxidation leads to partial self-discharge, capacity loss, and degradation, which may begin already during material handling, and whose origin remains unclear.Here, we combine electrochemical characterization with magnetometry to study three oxidation states of PBAs. Magnetic susceptibility measurements reveal changes in $Fe^2+$/$Fe^3+$ oxidation and spin states. Correspondingly, initial electrochemical cycles show distinct redox features at 2.7–3.1 V vs. Na/$Na^+$, reflecting different sodium contents and oxidation states. The electrochemical behavior correlates well with effective magnetic moments, indicating mixed high- and low-spin configurations of the iron redox centers |
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Copolymerisation of active esters and epoxides – model studies and catalyst screening
Peter Weiss, Christian Slugovc, ICTM, TU Graz
Abstract: The use of epoxy resin formulations in technical fields includes composite materials, encapsulation, coatings, structural adhesives, and numerous other applications. [1] For the curing of epoxy resins anhydrides are one of the most prevalent hardeners providing good thermal and mechanical properties. However, anhydrides bring along disadvantages for example the need of high temperatures and long reaction times. [2] Additionally, anhydrides entail certain hazards, making them the focus of potential prohibition measures and regulatory provisions. An alternative could be the use of active esters for the curing of epoxides. Model reactions to determine the mechanism of this reactions were carried out by Chen et al. [3] and delivered promising results, especially regarding the modification of the polymer backbone by the type of the active ester. This is particularly interesting for manufacturing when used with easily available chemicals such as diglycidyl ether of bisphenol A (DGEBA) and active diester species. [4]
To investigate alternative potential variations of active ester species, model reactions with phenyl glycidyl ether (PGE), catalysed with 4-dimethylaminopyridine (DMAP), were carried out. The most promising substance for this reaction was phenyl acetate. Using this system, the influence of different Lewis base catalysts was investigated as well.
[1]: Chen, X. M.; Ellis, B. Coatings and other applications of epoxy resins. Chemistry and Technology of Epoxy Resins 1993, 1, 303-325. DOI: 10.1007/978-94-011-2932-9_9
[2]: Pham, H. Q.; Marks, M. J. Epoxy Resins. Ulmann’s Encyclopedia of Industrial Chemistry 2005, 13, 155-244. DOI: 10.1002/14356007.a09_547.pub2
[3]: Chen, C. H.; Gu, Z. C.; Tsai, Y. L.; Jeng, R. J.; Lin, C. H. Identification of the reaction mechanism between phenyl methacrylate and epoxy and its application in preparing low-dielectric epoxy thermosets with flexibility. Polymer 2018, 140, 225-232. DOI: 10.1016/j.polymer.2018.02.045
[4]: Zhang, Y.; Peng, C.; Wang, G.; Huang, X.; Yu, Y. Hydroxyl-Free Epoxy Thermoplastics from Active Esters with Low Dielectric Constant and Water Sorption. ACS Appl. Electron. Mater. 2024, 6, 6, 4578-4586. DOI: 10.1021/acsaelm.4c00605
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Light-driven spatial control of dynamic thioester networks via photobase generators
Pia-Maria Egger, Polymer Competence Center Leoben
Abstract: Covalent adaptable networks (CANs) are crosslinked polymer structures that undergo dynamic bond exchange reactions when exposed to heat, enabling a reorganization of their topology. This distinctive property enables these polymers to combine the durability and chemical resistance of thermosets with the processing versatility and recyclability of thermoplastics. [1] In this study, we focused on thiol-thioester exchange reactions, which, with suitable catalysts, can proceed rapidly even at low temperatures, a characteristic that is especially relevant for biomedical applications. Initially, we produced vinyl monomers with thioester functionalities to promote network formation through a thiol-ene click reaction under visible light exposure. To achieve a spatial resolution of dynamic exchange reactions, 5 variations of TMG-based photobase generators (TMG-PLBs) were synthesized. These TMG-PLBs incorporate 1,1,3,3-Tetramethylguanidine as a strong base, along with phenylglyoxylic acid or its derivatives, which are modified with spacers or side groups. The purity of the monomers and the TMG-PLBs was characterized by 1H- and 13C-NMR spectroscopy. Via pH-measurements in methanol, the basicity of the synthesized compounds in dependency on the irradiation dose was determined. Subsequently, by using equimolar amounts of thiol and vinyl monomer, 3mol% TMG-PLB and 1 mol% phenyl-bis(2,4,6-trimethylbenzoyl)phosphinoxide (BAPO), the photosensitive resin was prepared. After curing the resin via 450 nm irradiation, spatially resolved activation of the photobase was accomplished through 365 nm UV-light illumination. To explore the resulting dynamic behavior, we conducted stress relaxation measurements at various temperatures. Additionally, differential scanning calorimetry and thermogravimetric measurements were performed to investigate the thermal material properties.
[1] Bongiardina N. J.; Long K. F.; Podgórski M.; Bowman C. N., Macromolecules 2021, 54, 8341 |
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Investigation of ion transport of water-in-salt electrolytes in the bulk and in multiporous carbon electrodes
Qamar Abbas, M. Tauhidul Islam, Bernhard Gollas
Abstract: Water-in-salt electrolytes are safe alternatives to organic electrolytes that exhibit improved stability, non-flammability, low cost, and a wide electrochemical potential window [1]. However, the higher viscosity of the water-in-salt electrolyte results in slow ion transport and insufficient wetting of subnanometer-sized pores in carbon electrodes resulting in a compromise between voltage, power density, energy density, and stability [2]. In addressing the limitations of PFG-NMR, SAXS and EQCM generally employed to elucidate ion transport behavior, our approach to quantify the diffusivity of lithium bis(trifluoromethanesulfonyl)imide and choline chloride-based water-in-salt electrolytes in the micro and meso-pores of a multiporous carbon is facile and reliable. The in-pore ion diffusivity was determined from the diffusivity values of the bulk electrolyte as well as the porosity and tortuosity of the carbon electrode. The average bulk ion diffusivity was obtained from PFG-NMR data found in the literature, while the porosity was measured from nitrogen gas adsorption/desorption data. The electrode's tortuosity was determined from electrochemical impedance spectroscopy. This method efficiently differentiates between the ion diffusivity within micro- and mesopores considering their respective pore volume and surface area fractions.
Acknowledgement: The authors thank the Austrian Research Promotion Agency for providing funds for the project number 39966764.
References:
[1]. L. Suo, O. Borodin, T. Gao, M. Olguin, J. Ho, X. Fan, C. Luo, C. Wang, K. Xu, Science 350 (2015) 938-943.
[2]. P. Lannelongue, R. Bouchal, E. Mourad, C. Bodin, M. Olarte, S. le Vot, F. Favier, O. Fontaine, J Electrochem Soc. 165 (2018) A657–A663.
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Process optimization of an AlB4C MMC welded using EBW
Riedl Helmut
Abstract: This study investigates electron beam welding (EBW) as a potential replacement for friction stir welding (FSW) for an aluminium-boron carbide (AlB4C)-based metal matrix composite (MMC). While FSW, as a solid-state process, typically does not produce pores, pore formation is a known problem in melting processes such as EBW. This significantly impacts component quality and mechanical properties.
The aim of this study is the systematic investigation of methods for reducing porosity in AlB4C welded samples using EBW. Various methodological approaches are pursued for this purpose, including parameter studies, the application of multi-bead technology, the variation of beam figures and frequencies, and the use of so-called sandwich models.
The experimental investigations are based on electron beam welded samples provided by pro-beam. Evaluation is carried out using metallographic analysis, light and scanning electron microscopy, and quantitative pore analysis.
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Frontal Polymerization of Dynamic Networks
Schmidleitner Christoph, Polymer Competence Center Leoben
Abstract: Frontal polymerization (FP) enables the conversion of monomers into polymers in a spatially confined reaction zone (front). There, the reaction zone spreads through the bulk material in an autocatalytic self-propagation. The front is driven by exother-mic heat generation, where the only necessary external energy input is during the initiation process. Frontal polymerization has been investigated for several mono-mers due to its rapid curing and its high energy efficiency.
Conventional thermal curing as well as photopolymerization offer severe drawbacks, though. In thermal polymerization processes extensive curing times and high ener-gy input are still issues, whereas photopolymerization is more rapid. However due to low penetration depth of light it is only possible for thin films. To overcome these drawbacks, various kinds of frontal polymerization were employed. Similar to con-ventional thermally and photo-cured networks, the polymer networks formed are characterized by high chemical and thermomechanical resistance. Nowadays, other important factors apart from energy efficiency also arise such as recyclability, reusa-bility and reprocessability. These can be implemented by the introduction of dynamic bonds into thermoset materials. This can be achieved using various kinds of bonds. Thus, in this work various chemical bond systems such as transesterification as well as coordinative bond exchange have been investigated for their applicability in fron-tal polymerization and dynamic networks.
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Crystallization Control in Tin Halide Perovskite Solar Cells
Stefan Moscher, ICTM
Abstract: Stefan Moscher (1), Sebastian Mairinger (1), Lukas Troi (1), Fernando Warchomicka (2), Gregor Trimmel (1), Thomas Rath (1)
1 Institute for Chemistry and Technology of Materials, NAWI Graz, Graz University of Technology, Stremayrgasse 9, 8010 Graz, Austria
2 Institute of Materials Science, Joining and Forming, Graz University of Technology, Kopernikusgasse 24, 8010 Graz, Austria
Perovskite solar cells have achieved efficiencies above 27% [1], but their reliance on toxic lead motivates the development of lead-free alternatives. Tin-based perovskites are a promising option due to their low toxicity, low cost, and lead-like electronic properties. Nowadays efficiencies of over 17% [2] are already reported. However, their performance is limited by Sn2+ oxidation and poor environmental stability, making further optimization necessary.
Antisolvent treatment, which plays a crucial role in perovskite crystallization was investigated in detail. Additionally, incorporating large A-cations such as phenethylammonium and related compounds to form quasi-2D tin perovskites can significantly improve device performance and stability compared to conventional 3D structures, with reachable efficiencies of up to 13.5%.
In the future, the focus will also be on alternative crystallization methods. The conversion of the precursor film into the perovskite layer by using atmospheric nitrogen plasma could be very promising. Initial tests show very good crystallization of the perovskite layer after just two seconds under the plasma.
References:
1. https://www.nrel.gov/pv/assets/pdfs/best-research-cell-efficiencies.pdf, NREL-Chart.
2. A. Abate, et al., Nat. Nanotechnol., 2025, 20(6), 719-720.
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Mechanochemical Synthesis of Oligo- and Poly-silanes
Thomas Lainer, Institute of Inorganic Chemistry
Abstract: Mechanochemistry refers to reactions, normally of solids, induced by the input of mechanical energy, such as grinding in ball mills. It is becoming more intensely studied because it can promote reactions between solids quickly and quantitatively. Moreover, the main advantage is that the reactions can be carried out with either no added solvent or only nominal amounts. Based on these advantages, mechanochemical approaches in an organic synthesis have received increased interest because of their wide applications in green methodologies. Ball milling has been fruitfully utilized in synthesizing various (elemental) organic scaffolds, including common drugs or drug candidates.[1] However, this type chemistry has so far been neglected for the main group elements.
Consequently, we set out and established a pathway towards silicon frameworks via mechanochemical synthesis.
[1]a) I. N. Egorov, S. Santra, D. S. Kopchuk, I. S. Kovalev, G. V. Zyryanov, A. Majee, B. C. Ranu, V. L. Rusinov, O. N. Chupakhin, Green Chem. 2020, 22, 302–315; b) A. Stolle, T. Szuppa, S. E. S. Leonhardt, B. Ondruschka, Chem. Soc. Rev. 2011, 40, 2317–2329; c) C. Thambiliyagodage, R. Wijesekera, Current Research in Green and Sustainable Chemistry 2022, 5, 100236. |
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Investigation of Inhibitor-Modified Chitosan: Catching Enzymes on Surfaces and in Bulk
Tobias Dorn, Alexander Luttenberger, Herwig Prasch, Elena Spari, Tobias Steindorfer, Martin Thonhofer, Karin Stana-Kleinschek, Tanja M. Wrodnigg, Rupert Kargl, TU Graz, Institute of Chemistry and Technology of Biobased Systems
Abstract: Glycoconjugates, like glycoproteins and glycolipids, make up an essential part of all cell surfaces and are taking part in many biological processes, for example in cell-cell communication. Additionally, most cells are covered in a glycan layer [1]. The solid liquid interface of such oligo- and polysaccharides is therefore of importance in biology and medicine, for example for cell adhesion and recognition processes [2]. Semi-synthetic polysaccharide interfaces can be used to mimic such surfaces for interaction studies for e.g. protein/enzyme binding.
We are interested in the interactions between glycosidases and polysaccharides modified with respective inhibitors. Therefore, small molecules, like imino- or isoiminosugars, are attached to e.g. chitosan or cellulose [3], which have been prepared to contain azido-groups, by azide-alkyne CLICK chemistry. This can be done on thin-film surfaces [4], which enables analysis techniques like AFM, QCM-D or SPR, as well as in bulk-material. One aim is to create materials that can be used for affinity chromatography of glycosidases. Additionally, lectins from bacteria like uropathogenic E. coli can be targeted by designing suitable antagonists [5]. Synthetic as well as analytical details of this approach will be presented.
[1] K. H. Moore; H. A. Murphy, E. M. George, Am. J. Physiol. Regul. Integr. Comp. Physiol. 2021, 320, R508-R518.
[2] E. Armingol, A. Officer, O. Harismendy, N. E. Lewis, Nat. Rev. Genet. 2021, 22, 71–88.
[3] A. Koschella, C.-Y. Chien, T. Iwata, M.S. Thonhofer, T.M. Wrodnigg, T. Heinze Macromol. Chem. Phys. 2020, 221, 1900343.
[4] T. Dorn, M. Finsgar, K. Stana-Kleinschek, T. Steindorfer, M. Thonhofer, T.M. Wrodnigg, R. Kargl, Chemical Monthly 2025, 156, 65-75.
[5] C. Spormann, T. Dorn, S. Schwaiger, S. Sdunnus, A. Koschella, H.-P. Kählig, T. Heinze, T.K. Lindhorst, T.M. Wrodnigg, Bioorg. Med. Chem. 2025, 127, 118236 |
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Mixed-configuration approximation for multiorbital impurity models out of equilibrium
Tommaso Mazzocchi
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Modulating Structure and Activity of Enzyme@ZIF Biocomposites Using 1-Methylimidazole
Verena Lipic, Institute of Physical and Theoretical Chemistry, TU Graz
Abstract: Verena Lipic, Francesco Carraro, Paolo Falcaro
Metal-Organic Frameworks (MOFs) are extended network materials composed of metal nodes and multitopic organic ligands, exhibiting a porous structure. One subclass of MOFs, designated as Zeolitic Imidazolate Framework(ZIF)-8, can be synthesized in an aqueous, biocompatible environment, making it suitable for immobilization and encapsulation strategies.[1] Our group has previously demonstrated that the synthesis conditions can significantly impact the crystal size and topology: smaller crystal sizes leading to higher enzymatic activity.[2] However, in the field of biocompatible synthesis, controlling particle size remains challenging, as additives commonly used in organic synthesis can negatively impact the native structure of the encapsulated biomacromolecule.[3]
To address this challenge, we selected 1-Methylimidazole (1-MiM) as a biofriendly modulator [4] to control the morphology and particle size, consequently impacting the catalytic performance of the enzyme@ZIF biocomposite. To investigate this, we synthesized a multivariable system incorporating three different ligand:metal ratios and varying amounts of 1-MiM. Furthermore, the synthesis was performed both in the absence of enzymes and in the presence of different enzymes (e.g. Bovine Serum Albumin, Horseredish Peroxidase) to demonstrate the versatility of the enzyme@ZIF system.
[1] Liang, K., et al. Nat. Comm. 6 (2015) 7240.
[2] Maddigan, N., et al. ACS Appl. Mater. Interfaces 13(44) (2021) 51867-51875.
[3] Liang, W., et al. J. Chem. Rev. 121(3) (2021) 1077-1129.
[4] Yu, Y., et al. Cryst. Growth Des. 20(10) 2020 6528-6534.
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Thermal Stability and Morphological Evolution of Polymer Donors in Organic Solar Cells
Virginia Lafranconi, ICTM
Abstract: Virginia Lafranconi, Thomas Rath and Gregor Trimmel
Recently, organic solar cells (OSCs) based on non-fullerene acceptors have achieved significant improvements in power conversion efficiency (PCE), however long-term operational stability remains a major challenge for their commercialization [1]. Enhancing the photostability of polymer donors has been identified as a crucial and direct strategy for improving the overall stability of OSC devices [2], highlighting that photodegradation behavior is primarily governed by the chemical degradation of the donor component [3]. Under continuous illumination, elevated operating temperatures typically impose thermal stress, which can accelerate detrimental morphological changes in the active layer. This metastable morphology is considered one of the main obstacles to achieving high efficiency and stable OSCs [1]. In this preliminary study, we investigate the correlation between morphology and stability by examining the thermal degradation pathways of two representative donor polymers - D18 and PM6 - paired with a standard non-fullerene acceptor, L8BO, in binary systems by varying the donor:acceptor ratio. The morphological evolution of the active layers under thermal stress is monitored using ex-situ GIWAXS measurements. In PM6-based devices, the π-π stacking distance remains unchanged with heating, providing an enhanced molecular packing and enlarged domain sizes. In contrast, D18-based systems exhibit the emergence of multiple peaks at elevated temperatures, suggesting recrystallization and disruption in molecular ordering. The temporal evolution of normalized solar cell parameters was monitored in devices aged in a dark and inert environment 85 degC. Across all systems, the observed decrease in PCE is primarily driven by losses in open-circuit voltage (Voc) and fill factor (FF), reflecting structural changes in the active layer, especially in vertical packing, detrimental to charge transport. Notably, a reduction in donor content leads to a corresponding decrease in the burn-in loss characteristic of degradation profiles. These findings can together with further complementary spectroscopic studies, provide a more detailed analysis of phase distribution, structural modifications, and chemical bond stability within the active layer.
[1] An, K., Zhong, W., Peng, F., Deng, W., Shang, Y., Quan, H., ... & Ying, L. (2023). Mastering morphology of non-fullerene acceptors towards long-term stable organic solar cells. Nature Communications, 14(1), 2688. [2] Han, J., Xu, H., Paleti, S. H. K., Sharma, A., & Baran, D. (2024). Understanding photochemical degradation mechanisms in photoactive layer materials for organic solar cells. Chemical Society Reviews.
[3] Zhao, Y., Wu, Z., Liu, X., Zhong, Z., Zhu, R., & Yu, J. (2021). Revealing the photo-degradation mechanism of PM6: Y6 based high-efficiency organic solar cells. Journal of Materials Chemistry C, 9(39), 13972-13980.
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