A5002183096- X-ray Diffraction in Crystallography
- Advanced Thermoelectric Materials and Devices
- Ferroelectric and Piezoelectric Materials
- Crystallization and Solubility Studies
- Electronic and Structural Properties of Oxides
- Microwave Dielectric Ceramics Synthesis
- Thermal properties of materials
- Multiferroics and related materials
- Thermal Expansion and Ionic Conductivity
- Chalcogenide Semiconductor Thin Films
- Acoustic Wave Resonator Technologies
- Crystallography and molecular interactions
- Optical properties and cooling technologies in crystalline materials
- Heusler alloys: electronic and magnetic properties
- Thermal Radiation and Cooling Technologies
- Transition Metal Oxide Nanomaterials
- Catalytic Processes in Materials Science
- Nuclear materials and radiation effects
- Advanced Condensed Matter Physics
- Machine Learning in Materials Science
- Advanced ceramic materials synthesis
- Zeolite Catalysis and Synthesis
- Gas Sensing Nanomaterials and Sensors
- CO2 Sequestration and Geologic Interactions
- Perfectionism, Procrastination, Anxiety Studies
Norwegian University of Science and Technology
2017-2022
Aarhus University
2014-2021
Trondheim Kommune
2018-2019
Google (United States)
2018
Aarhus School of Architecture
2017
Thermoelectric materials require an optimal carrier concentration to maximize electrical transport and thus thermoelectric performance. Element doping composition off-stoichiometry are the two general effective approaches for optimizing concentrations, which have been successfully applied in almost all semiconductors. In this study, we propose a new strategy called bonding energy variation tune concentrations Cu2Se-based liquid-like compounds. By utilizing different bond features Cu2Se Cu2S,...
Accurate structural models of reaction centres in zeolite catalysts are a prerequisite for mechanistic studies and further improvements to the catalytic performance. The Rietveld/maximum entropy method is applied synchrotron powder X-ray diffraction data on fully dehydrated CHA-type zeolites with without loading catalytically active Cu 2+ selective reduction NO x NH 3 . identifies known sites six-membered ring not previously observed site eight-membered ring. sum refined occupancies these...
Extremely low thermal conductivity and high thermoelectric performance are found in liquid-like Cu<sub>2</sub>Se<sub>1−x</sub>S<italic>x</italic> polymorphic materials.
The global ambition of reducing the carbon dioxide emission makes sequestration reactions attractive as an option storing CO2. One promising environmentally benign technology is based on forming thermodynamically stable carbonated minerals, with drawback that these usually have low conversion rates. In this work, carbonation reaction Mg rich olivine, Mg2SiO4, under supercritical conditions has been studied. produces MgCO3 at elevated temperature and pressure, addition NaHCO3 NaCl to improve...
We demonstrate that the quality factor of Cu<sub>2</sub>Se<sub>1−x</sub>Te<sub>x</sub> solid solutions is higher than those most typical thermoelectric materials.
The crystal structure uniquely imparts the specific properties of a material, and thus provides starting point for any quantitative understanding thermoelectric properties. Cu 2− x Se is an intensely studied high performing, non-toxic cheap here first time, average β-Cu reported based on analysis multi-temperature single-crystal X-ray diffraction data. It consists Se–Cu layers with additional copper between every alternate layer. structural changes during peculiar zT enhancing phase...
By means of normal-incidence, high-flux and high-energy X-rays, total scattering data for pair distribution function (PDF) analysis have been obtained from thin films (tf), suitable local structure analysis. using amorphous substrates as support the films, standard Rapid Acquisition PDF setup can be applied signal film isolated through subtraction an independently measured background signal. No angular corrections to are needed, would case grazing incidence measurements. The 'tfPDF' method...
Ag doping in β-Zn<sub>4</sub>Sb<sub>3</sub> leads to the enhanced thermoelectric figure-of-merit (<italic>zT</italic>) and improved high-temperature thermal stability.
ZnSb is a promising low cost, non-toxic thermoelectric material, but large scale applications require development of fast and easy synthesis methods.
Zn4Sb3 is among the cheapest high performance thermoelectric materials, and it made of relatively nontoxic elements. Strong activities are aimed at developing commercial power generation modules based on making vital to develop fast reliable synthesis processes for high-quality material. Here direct compaction homogeneous phase-pure by spark plasma sintering (SPS) has been developed. Compared with traditional quench press method, complexity process time new method very significantly reduced...
Organic-inorganic hybrid materials are attractive due to the combination of properties from two distinct types materials. In this work, transparent titania-polydimethylsiloxane with up 15.5 vol. % TiO2 content were prepared by an in situ non-aqueous method using titanium (IV) isopropoxide and hydroxy-terminated polydimethylsiloxane as precursors. Spectroscopy (Fourier transform infrared, Raman, Ultraviolet-visible, ellipsometry) small-angle X-ray scattering analysis allowed describe detail...
Homogeneous reaction precursors may be used to form several solid-state compounds inaccessible by traditional synthetic routes, but there has been little development of techniques that allow for a priori prediction what crystallize in given material system. Here, the local structures FeSbx designed are determined and compared with structural motifs their crystalline products. X-ray total scattering atomic pair distribution function (PDF) analysis show first nucleate metastable FeSb3 compound...
The thermal evolution of the crystal structure and phase transitions KNbO3 were investigated by high-temperature powder X-ray diffraction Rietveld refinement data. Two from orthorhombic (Amm2) to tetragonal (P4mm) cubic ( Pm3¯m ) confirmed, both on heating cooling. Both are first order based observed hysteresis. mixed displacive order-disorder nature transition is argued symmetry apparent divergence atomic positions pseudo-cubic values. between shows no temperature-dependence for only...
Ferroelectric materials are crucial for today’s technological society and nanostructured ferroelectric important the downscaling of devices. Controlled reproducible synthesis these are, therefore, immense importance. Hydrothermal is a well-established route, with large parameter space optimization, but better understanding nucleation growth mechanisms needed full utilization control. Here we use in situ X-ray diffraction to follow BaTiO3 formed by hydrothermal using two different titanium...
Destabilization of the type I clathrate Ba<sub>8</sub>Ga<sub>16</sub>Ge<sub>30</sub>at moderate temperatures has been revealed, prompting thermoelectric community to consider impact operational on stability and reliability high<italic>zT</italic>materials.
Carbonate formation is a prevailing challenge in synthesis of BaTiO3, especially through wet chemical routes. In this work, we report the phase evolution during thermal annealing an aqueous BaTiO3 precursor solution, with particular focus on structures and role intermediate phases forming prior to nucleation. situ infrared spectroscopy, X-ray total scattering, transmission electron microscopy were used reveal decomposition, pyrolysis, crystallization reactions occurring processing. Our...
Abstract The prototype piezoelectric material BaTiO 3 is widely used in e.g., capacitators. Chemical solution deposition (CSD) of films a simple and environmentally friendly processing route, but insight the crystallization process crucial to tailor film properties. In this work, influence annealing conditions on behavior thin from aqueous chemical presented. situ synchrotron X-ray diffraction was reveal phase evolution, films, study how degree crystallographic texture polycrystalline...
Understanding the crystallization process for chemical solution deposition (CSD) processed thin films is key in designing fabrication strategy obtaining high-quality devices. Here, an situ sample environment presented studying of CSD under typical processing parameters using near-grazing-incidence synchrotron X-ray diffraction. Typically, pyrolysis performed a rapid thermal (RTP) unit, where high heating rates, temperatures and atmosphere control are main parameters. The setup can reach...
Abstract Controlling the shape and size of nanostructured materials has been a topic interest in field material science for decades. In this work, ferroelectric Sr x Ba 1− Nb 2 O 6 ( x= 0.32–0.82, SBN) was prepared by hydrothermal synthesis, morphology is controllably changed from cube‐shaped to hollow‐ended structures based on fundamental understanding precursor chemistry. Synchrotron X‐ray total scattering PDF analysis used reveal structure Nb‐acid precursor, showing Lindqvist‐like motifs....
Zinc antimonide compounds are among the most efficient thermoelectric (TE) materials with exceptional low thermal conductivity at moderate temperatures up to 350 °C. This study aims evaluate performance of a zinc thin film TE deposited on an insulating substrate, while heat flows in plane film. At first, effect applying different hot side specimen is investigated reach steady state open circuit analysis. Then, focuses and stability analysis element operating under resistive loads over wide...
Advanced<italic>in situ</italic>techniques provide knowledge about crystal growth mechanisms of Sr<sub>x</sub>Ba<sub>1−x</sub>Nb<sub>2</sub>O<sub>6</sub>facilitating the design microstructure and determination stoichiometry.