Article
Chemistry, Multidisciplinary
Jiawei Zhang, Daisuke Ishikawa, Michael M. Koza, Eiji Nishibori, Lirong Song, Alfred Q. R. Baron, Bo B. Iversen
Summary: We have revealed the correlation between loosely bonded atoms and strong anharmonicity in thermoelectric material InTe, using chemical bonding analysis, inelastic X-ray and neutron scattering, and first principles phonon calculations. Our findings indicate that highly anharmonic phonons in InTe arise from the covalency between delocalized In1+ 5s(2) lone pair electrons and Te 5p states. This work provides insights into the microscopic origin of strong anharmonicity in rattling atoms and has implications for designing efficient thermoelectric materials.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Physics, Applied
Karl F. F. Fischer, Bjarke B. Demant, Lasse R. Jorgensen, Bo B. Iversen
Summary: Ruthenium arsenide can be made p-type by adding germanium, and it has a wide substitution range without affecting stability. RuAs2-xGex (x = 0.02, 0.04, 0.08, 0.16, 0.32, and 0.64) shows that the saturation limit of germanium is between 0.16 and 0.32. The electrical contribution to thermoelectric performance is greatly improved with a power factor of 1.03 mW/(m K-2). However, the lattice rigidity is not affected by substitution, as the Debye temperature remains around 420 K, resulting in a modest maximum zT of 0.11.
APPLIED PHYSICS LETTERS
(2023)
Article
Chemistry, Physical
Sajesh P. Thomas, Anna Worthy, Espen Z. Eikeland, Amy J. Thompson, Arnaud Grosjean, Kasper Tolborg, Lennard Krause, Kunihisa Sugimoto, Mark A. Spackman, John C. McMurtrie, Jack K. Clegg, Bo B. Iversen
Summary: This article reports a mechanically flexible one-dimensional coordination polymer that exhibits elastic bending. By utilizing various techniques including XRD, high-pressure crystallography, synchrotron micro-XRD mapping, and high-resolution synchrotron X-ray charge density analysis, the inter and intra-chain bonding as well as structural flexibility were quantitatively investigated. The results reveal that the helical coordination polymer behaves like a spring when subjected to external stimuli. The exceptional coordination sphere flexibility, attributed to the presence of Jahn-Teller distorted coordination bonds, contributes to the polymer's flexibility.
CHEMISTRY OF MATERIALS
(2023)
Article
Chemistry, Physical
Jonathan Quinson, Olivia Aalling-Frederiksen, Waynah L. Dacayan, Joachim D. Bjerregaard, Kim D. Jensen, Mads R. V. Jorgensen, Innokenty Kantor, Daniel R. Sorensen, Luise Theil Kuhn, Matthew S. Johnson, Maria Escudero-Escribano, Soren B. Simonsen, Kirsten M. O. Jensen
Summary: This article introduces a surfactant-free synthesis method for gold nanoparticles, which can achieve stable and size-controlled colloidal gold nanoparticles for months by reducing HAuCl4 with low-viscosity mono-alcohols and water at room temperature in alkaline solutions, without the need for other additives. Pd and bimetallic AuxPdy NPs, nanocomposites, and multimetallic samples can also be obtained and act as active (electro)catalysts. This simple synthesis method has multiple advantages over the state-of-the-art syntheses in fundamental and applied research.
CHEMISTRY OF MATERIALS
(2023)
Article
Chemistry, Physical
Brian Dusolle, Veronique Jubera, Evgeniy S. Ilin, Patrick Martin, Gilles Philippot, Matthew R. . Suchomel, Bo B. Iversen, Samuel Marre, Cyril Aymonier
Summary: Extensive research on nanosized ZnO finds its optical properties challenging to control due to various possible defects producing emissions in the visible range. A low-temperature, supercritical-fluid-driven synthesis proposed by our group produces isotropic nanosized particles with a pure excitonic emission comparable to single crystals. This article reports the growth mechanism and optical properties of the excitonic emission, as well as its phonon coupling with the E2 high vibrational mode at liquid helium temperatures.
CHEMISTRY OF MATERIALS
(2023)
Article
Chemistry, Physical
Kristoffer Visti Graae, Xinyu Li, Daniel Risskov Sorensen, Elixabete Ayerbe, Iker Boyano, Denis Sheptyakov, Mads Ry Vogel Jorgensen, Poul Norby
Summary: Silicon-graphite blended electrodes in Li-ion batteries have been investigated to utilize the high capacity of Si while minimizing the negative effects of volume expansion. NMC 811 is an advanced layered oxide cathode material with reduced cobalt content. These two materials show great potential in achieving electric vehicle targets, but their degradation mechanism is not completely understood. In this study, 5 Ah prototype multi-layer pouch cells were fabricated using these materials and studied using neutron and synchrotron X-ray diffraction techniques. The results reveal inhomogeneities across both electrodes during degradation, which are related to the inhomogeneous volume expansion of the Si-graphite anodes.
JOURNAL OF POWER SOURCES
(2023)
Article
Materials Science, Multidisciplinary
Matti Isakov, Veera Langi, Lalit Pun, Guilherme Correa Soares, Innokenty Kantor, Mads Ry Vogel Jorgensen, Mikko Hokka
Summary: This paper presents a methodology that combines mechanical tests with synchrotron X-ray diffraction measurements to study the loading rate dependency of mechanically induced phase transformations in steels. The experiments were conducted at the DanMAX beamline with a custom-made tensile loading device and in-situ optical imaging system. The results demonstrate the feasibility of this methodology by providing novel data on the kinetics of the martensitic phase transformation in EN 1.4318-alloy following a rapid increase in strain rate.
METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE
(2023)
Article
Chemistry, Physical
Lise Joost Stockler, Rasmus Stubkjaer Christensen, Magnus Klove, Andreas Dueholm Bertelsen, Anders Baek Borup, Lennard Krause, Seiya Takahashi, Tomoki Fujita, Hidetaka Kasai, Ichiro Inoue, Eiji Nishibori, Bo Brummerstedt Iversen
Summary: Promising results were obtained from PDF analysis using X-ray scattering data on a suspension of HfO2 nanoparticles measured at the SACLA XFEL facility. The study encourages further research in ultrafast structural science.
Article
Chemistry, Inorganic & Nuclear
Nicolas P. L. Magnard, Andrea Kirsch, Mads R. V. Jorgensen, Innokenty Kantor, Daniel R. Sorensen, Simo Huotari, Svemir Rudic, Heloisa N. Bordallo, Kirsten M. O. Jensen
Summary: Manganesedioxide is a promising material for energy storage and conversion due to its rich electrochemistry and wide polymorphism. This study investigates the influence of hydrothermal synthesis parameters on the amount and type of H-related defects in γ-MnO2 nanoparticles. The results show that synthesis temperature and time independently affect the two types of defects, and the defect density varies from particle core to surface.
INORGANIC CHEMISTRY
(2023)
Article
Materials Science, Multidisciplinary
Jing Kong, Alicia Manjon-Sanz, Jue Liu, Frederick Marlton, Tsz Wing Lo, Dangyuan Lei, Mads Ry Vogel Jorgensen, Abhijit Pramanick
Summary: We demonstrate that the oxygen octahedral tilt (R) and polarization (P) in the A3B2O7 Ruddlesden-Popper hybrid improper ferroelectric (Ca, Sr)3Ti2O7 follows a 2D Ising class scaling behavior near the para-to-ferroelectric transition temperature (Tc), contrary to the conventional mean-field Landau-type behavior. Additionally, we observe that P undergoes a transition from 2D Ising to 3D mean-field critical behavior at a temperature Td < Tc, which is driven by enhanced interlayer dipolar correlations arising from the increase in ferroelectrically active B-site centered dipoles.
Article
Materials Science, Multidisciplinary
Martin Ottesen, Emma Ehrenreich-Petersen, Camilla Hjort Kronbo, Francois Baudelet, Lucie Nataf, Innokenty Kantor, Mads Ry Vogel Jorgensen, Martin Bremholm
Summary: The structural properties of the hexagonal multiferroic h-HoMnO3 under high pressure were investigated using synchrotron x-ray diffraction and x-ray absorption spectroscopy. It was observed that the structure undergoes a pressure-induced phase transition at -24 GPa, forming a rhombohedrally distorted superstructure similar to the oxygen-loaded h-RMnO3+delta phases. This phase transition is driven by the compressible ab plane, which leads to a gradual charge disproportionation of Mn(III) with increasing pressure.
Article
Chemistry, Multidisciplinary
Ida Gjerlevsen Nielsen, Magnus Klove, Martin Roelsgaard, Ann-Christin Dippel, Bo Brummerstedt Iversen
Summary: In this study, the formation mechanisms and crystal structure transformations of gallium oxides during solvothermal synthesis were investigated using in situ X-ray diffraction. It was found that the formation mechanism of γ-Ga2O3 involves the transformation from γ-Ga2O3 to β-Ga2O3, while GaOOH and Ga5O7OH form in aqueous solvent at low temperatures. The properties of the resulting products can be controlled by adjusting synthesis parameters such as temperature, heating rate, solvent and reaction time.
Article
Chemistry, Multidisciplinary
Sandeep K. Gupta, Hannah H. Nielsen, Andreas M. Thiel, Emil A. . Klahn, Erxi Feng, Huibo B. Cao, Thomas C. Hansen, Eddy Lelievre, Arsen Gukasov, Iurii Kibalin, Sebastian Dechert, Serhiy Demeshko, Jacob Overgaard, Franc Meyer, Franc Meyer
Summary: In this study, a highly anisotropic single-ion magnet (SIM) with stability under ambient conditions was synthesized and comprehensively characterized. The influence of the ligand field on the degeneracy and population of d-orbitals in a specific coordination environment was investigated, providing important insights for the rational design and enhancement of magnetic anisotropy in SIMs.
Article
Chemistry, Multidisciplinary
Anders Baek Borup, Andreas Dueholm Bertelsen, Magnus Klove, Rasmus Stubkjaer Christensen, Nils Lau Nyborg Broge, Ann-Christin Dippel, Mads Ry Vogel Jorgensen, Bo Brummerstedt Iversen
Summary: This study reveals the formation mechanism of PdxPby intermetallic nanoparticles through in situ solvothermal synthesis and ex situ autoclave synthesis, and investigates their catalytic effect in the hydrogen evolution reaction.
Article
Materials Science, Multidisciplinary
Priyank Shyam, Frederik H. Gjorup, Mathias I. Morch, Amalie P. Laursen, Anna Z. Eikeland, Innokenty Kantor, Mads R. V. Jorgensen, Mogens Christensen
Summary: The study developed a custom-built sample environment to investigate the structural evolution of materials during sintering using high-energy two-dimensional synchrotron X-ray diffraction. The in situ approach allowed real-time tracking of changes in structure and quantitative texture analysis, providing insights into the synthesis-structure-property relationships in sintered materials.
APPLIED MATERIALS TODAY
(2023)
