Research team

Electron microscopy for materials research (EMAT)

Expertise

Crystal structure characterisation of materials (with a focus on perovskite based materials and lithium battery cathode materials) using electron crystallography.

Functionally graded electrodes for long-life lithium -sulfur batteries (FUGELS). 01/05/2021 - 30/04/2025

Abstract

This project aims to develop the achitectures of sulphur- and lithiumelectrodes to improve the properties and lifetime of the next generation of batteries, i.e. lithium sulfur batteries (LSB). The innovative sulphurelectrodes provide a simultaneous increase of the sulphur load and stability of electronic/ionic contacts over long and short distances in the cel. This is achieved through an approach based on the gradual decoration of sulphur particles and electrodes by the so-called traps of the polysulfide (PS-trap). The project also aims to increase the safety and energy density of the LSB's by developing thin protected lithiumelectrodes.

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Air Carbon Recycling for Aviation Fuel Technology (4AirCRAFT). 01/05/2021 - 30/04/2024

Abstract

4AirCRAFT's ultimate goal is to develop a next generation of stable and selective catalysts for the direct CO2 conversion into liquid fuels for the aviation industry, enabling the synthesis of sustainable jet fuel. 4AirCRAFT will overcome the current challenges by combining three main reactions into one reactor to increase the CO2 conversion rate and reduce energy consumption. 4AirCRAFT technology will produce sustainable jet fuel at low temperature (below 80 ºC), contributing to a circular economy and leading to a decrease in GHG and reduced dependence on fossil fuel-based resources. In order to achieve this goal, we will move beyond the SoA by precisely integrating and taking advantage of biocatalysts, inorganic nanocatalysts, electrocatalysts, and their controlled spatial distribution within application tuned catalyst carrier structures. These catalyst carrier structures will be based on metal-organic frameworks and engineered inorganic scaffolds with hierarchical porosity distribution. This will unravel the activity of catalytic active phases and materials based on earth-abundant elements allowing us to achieve high CO2 conversion percentages and selectivity towards jet fuels (C8−16). By achieving this we will be able to circumvent the need for Fischer–Tropsch synthesis, that is unselective for the synthesis of fuels, therefore eliminating further steps for hydrocracking or hydrorefining of Fischer–Tropsch waxes. In terms of inorganic catalysts, size and shape of metal NPs, metal clusters, and single atoms at the surface of catalyst carrier structures will be developed, and precise structure-performance-selectivity relationships will be established. In terms of biocatalyst, special emphasis will be given to assure the long-term stability of deployed enzymes through programmed anchoring and shielding from detrimental reaction conditions. Together application tuned catalyst carrier structures will be employed to steer selectivity towards C8−16 molecules.

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Project website

Electron Nanocrystallography (NanED). 01/03/2021 - 28/02/2025

Abstract

The atomic structure determination of inorganic, organic and macromolecular compounds is a hard challenge anytime the crystal size falls below the micron range, becoming no more suitable for single-crystal x-ray diffraction. Still, a number of chemicals with valuable commercial and medical implications can be synthesized only as nanocrystals or show phase/polymorphic transitions during crystal growth. The development of more efficient tools able to disclose the nature of nanocrystalline materials is therefore a hot and transversal topic that links materials science, physics of diffraction, new instrument engineering, chemical production and pharmacology. Electron diffraction (ED) allows extracting structure information from single nanometric crystals. ED experienced a tremendous boost after the development of 3D routines for data collection, up to be enlisted among the main breakthroughs in Science. However, the development of 3D ED is still limited to few laboratories and is slowed by the lack of dedicated instrumentation. NanED aims to form a new generation of electron crystallographers, able to master and develop 3D ED techniques in an interdisciplinary and interconnected network, where competences and know-how of usually distant scientific sectors are shared and merged. NanED will gather all European scientists hitherto active in 3D ED development and a pool of large and small companies interested in instrument development and material or pharmaceutical production. NanED will deliver portable procedures for sample preparation, data collection and data analysis, suitable for the successful application of 3D ED to all kinds of compounds. NanED will also establish a new standard of crystallographic training, closer to nowadays industrial needs. Finally, NanED will favor the dissemination of 3D ED in academic and industrial laboratories, pushing Europe to be the leader for nanomaterial characterisation and development, with a noticeable and global economic impact.

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Project website

Automated Electron diffractometer for high throughput identification of nanocrystalline materials. 01/10/2020 - 30/09/2024

Abstract

The study of the structure of nanocrystalline materials is often difficult as standard X-ray diffraction techniques break down for sub micrometer particles, especially when occurring in a mixture. This is resolved by trying to crystallize specific compounds in larger crystals, but this is often problematic and time consuming. State of the art single crystal X-ray diffraction moreover requires a trip to a synchrotron which creates unnecessary long delays between growing a new structure and determining its structure. Electron diffraction provides an alternative for X-ray diffraction and excels especially for nanoscale crystals as it provides several orders of magnitude more information per volume for the same radiation damage. However, so far, electron diffraction is performed on expensive and difficult to handle transmission electron microscopes (TEM) requiring extensive interaction from highly trained researchers. This makes the technique rather unattractive for industrial demands where ease of use, high throughput, statistics and reproducibility are key concerns that don't fit well with the reality of TEM instruments in university labs. In this project, we propose to build a prototype electron diffractometer instrument on the basis of a modest Scanning Electron Microscope (SEM). The instrument will take a properly prepared nanocrystalline powder and automatically perform a full diffraction analysis on a very large number of particles without human interaction. This data is then fed into an automated structure refinement program and results in a full report on the structure and abundance of the particles found. An in house proof of concept shows that the obtained quality of diffraction data is excellent although several scientific issues will require attention. We propose to demonstrate this instrument on industry relevant materials in close interaction with several companies in Flanders that expressed strong interest in the capabilities of such instrument.

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New method to acquire in situ information on crystal structures changed by chemical reactions. 01/01/2020 - 31/12/2023

Abstract

In this project, we will be the first to determine structural changes at unit cell level during oxidation and reduction processes in situ in gasses and liquids with electron diffraction tomography. In situ means that the data is collected on the sample while it is still in the environment where the reaction occurred. Such oxidation and reduction processes are important in the field of energy materials, a research field with very high activity worldwide as sustainable energy is of vital importance for our whole society. Changes in structures under oxidation and reduction processes dictate ion conduction paths and reversibility, thus efficiency, capacity and lifetime of the different technologies. Such structural changes are currently followed using X-ray and neutron powder diffraction techniques, because the materials are usually only active as submicron particles. Although these techniques can uncover very important structural changes, they are often plagued by peak overlap of different phases and peak broadening due to the small crystal sizes, making the results less conclusive and leaving some structures unsolved. Using electrons will allow performing in situ single crystal experiments on the individual particles within a powder sample, due to the much stronger interaction between electrons and matter. Single crystal data has a lot of advantages over powder diffraction data for structure determination and will allow uncovering information and determining structures out of reach of in situ powder diffraction techniques. Precession electron diffraction tomography is already used for structure determination from ex situ single crystal data. Using this technique in situ, we will monitor how structures of materials change under oxygen atmosphere or reducing hydrogen atmosphere, under hydration or carbon dioxide, or under electrochemical oxidation and reduction. Our goal is to be the pioneers in using this technique of in situ PEDT and to demonstrate to the international materials science community the high value of the technique by providing missing structural information on several compounds from the field of energy materials. The compounds are selected from the fields of lithium-ion and polyanionic battery materials, solid oxide fuel cells, proton conducting fuel cells and chemical looping in order to reach a wide audience.

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Towards improved high capacity layered electrode materials for Liion batteries through atomic-level understanding of the redox reactions. 01/01/2020 - 31/12/2022

Abstract

Rechargeable Li-ion batteries are a pillar of our current technology driven society. More energy per mass unit can be stored in layered high capacity cathodes but they suffer from the voltage fade and voltage hysteresis reducing their energy efficiency. These detrimental effects mainly originate from the structural changes in the cathode material during charge and discharge. Recent developments have led to a paradigm shift, by showing that in these promising cathodes the oxygen oxidation, contributing to high capacity, is inherently linked with transition metal cation migration upon cycling. Together, they cause the voltage hysteresis and voltage fade. Gaining understanding of the complex interplay and control over both is necessary to exploit the advantages while eliminating the detrimental effects. To monitor both effects systematically and separate from the influence of the microstructure, we will synthesize new model structures with dedicated structural variations of the initial crystal structure and microstructure. We will study their structural changes upon cycling with state-of-the-art structure characterization techniques, and relate them to the electrochemical properties. This project will thus result in new viable Li-ion battery cathodes and allow the comprehensive understanding of the role of the microstructure, local structure and local valence for the stability of Li-rich layered cathodes, major candidates for future advanced rechargeable Li-ion batteries.

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Deciphering defects in Metal-Organic Framework nanocrystals using electron diffuse scattering analyses. 01/10/2019 - 30/09/2022

Abstract

The study of disorder has become a major aspect in the engineering of Metal Organic Frameworks (MOFs) since materials scientists recognised the strong influence of structural imperfections on MOFs functional properties. As the interest in MOFs' defect engineering grows exponentially, this practice becomes more and more precise in tailoring the type and distribution of defects. However, the structural characterisation possibilities still cannot guarantee an adequate quantitative precision. This is mainly due to the limited development of total scattering single crystal analyses on nanocrystals, which are a vast majority of the employed MOFs. My project aims to fill this gap by developing a novel method based on the use of electron diffuse scattering from Transmission Electron Microscopy analyses. The proposed method will be applied on a heterogeneous set of widely used nano-MOFs with unknown defects. This will at the same time define unambiguously their defect structures for the first time and validate the method to make it available for use in any research group. The acquired information will eventually be combined with the one achievable by bulk analyses to compensate for the limited statistical representativeness of single crystal analyses. This will allow to obtain a complete description of these materials' structure and to define general guidelines for the investigation of defects in nanomaterials by using methods available for the general use.

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Quantification of 3D correlated disorder in materials from electron diffraction diffuse scattering with application to lithium battery materials. 01/01/2019 - 31/12/2022

Abstract

The first aim of this project is to determine whether it is possible to quantify the three dimensional correlated disorder in materials using the three dimensional diffuse scattering in electron diffraction patterns. Correlated disorder is any type of deviation from an average structure that is correlated between neighbouring unit cells only. Many open questions in materials science are related to this correlated disorder. If we can use electron diffraction to refine correlated disorder, we gain access to single crystal information also for the submicron sized crystals in powder samples, which are often the only available form. We will use electron diffraction methods proven to work for Bragg scattering (sharp reflections) and combine these with algorithms from the fields of X-ray and neutron diffraction diffuse scattering. The second aim of this project is to analyze qualitatively and quantitatively the electron diffraction Bragg and diffuse scattering in lithium-ion battery materials to characterize the structural changes upon electrochemical cycling. This is important fundamental knowledge for gaining control over the degradation in lithium batteries. For this, we will quantify electron diffraction data obtained in situ in an electrochemical liquid cell. Doing this, we will not only provide new knowledge on the materials under investigation, but also introduce a new means to access a wealth of currently unavailable information on battery materials.

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In situ TEM study of interphase evolution in LiPON-based thin-film all-solid-state batteries. 01/11/2019 - 31/10/2020

Abstract

All-solid-state lithium ion batteries (ASSBs) have the potential to become the next generation of energy storage devices because of their better safety and higher energy density, compared to conventional liquid electrolyte lithium ion batteries. Currently, the performance of ASSBs is limited by interfacial resistance at the electrode/electrolyte interfaces, due to the formation of solidelectrolyte interphases (SEIs). Whereas most SEIs are unwanted, artificial SEIs i.e. thin coatings between the electrode and the solid electrolyte, are also investigated to, oppositely, protect against the degradation of the electrode/electrolyte interface and to reduce the interfacial resistance. In this project, I will determine the crystal structure of the SEIs between LiPON and several commercially relevant cathode materials at different stages during cycling. I will do this, to my knowledge for the first time, by using electron diffraction techniques while charging and discharging a thin-film ASSB in a cell filled with inert argon gas inside a transmission electron microscope. This will prevent that the results are influenced by relaxation, electron beam damage, gas evaporation, or reactions due to air exposure. I will also study the application of artificial SEIs at the LiPON/cathode interfaces. The experimental findings will be compared with recent theoretical models that try to explain SEI formation. Measures to increase battery performance will be proposed.

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Infrastructure for imaging nanoscale processes in gas/vapour or liquid environments. 01/05/2018 - 30/04/2021

Abstract

Processes in energy applications and catalysis as well as biological processes become increasingly important as society's focus shifts to sustainable resources and technology. A thorough understanding of these processes needs their detailed observation at a nano or atomic scale. Transmission electron microscopy (TEM) is the optimal tool for this, but in its conventional form it requires the study object to be placed in ultrahigh vacuum, which makes most processes impossible. Using environmental TEM holders, the objects can be placed in a gas/vapour or liquid environment within the microscope, enabling the real time imaging, spectroscopic and diffraction analysis of the ongoing processes. This infrastructure will enable different research groups within the University of Antwerp to perform a wide range of novel research experiments involving the knowledge on processes and interactions, including among others the growth and evolution of biological matter, interaction of solids with gasses/vapours or liquid for catalysis, processes occurring upon charging and discharging rechargeable batteries, the nucleation and growth of nanoparticles and the detailed elucidation of intracellular pathways in biological processes relevant for future drug delivery therapies and treatments.

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Structural and physico-chemical properties of new perovskite based compounds. 01/03/2016 - 31/08/2016

Abstract

Perovskite based materials can be tailored to exhibit a host of physical properties, ranging from ferroelectricity and ferromagnetism, to superconductivity and ion conductivity. Any success in synthesizing new perovskite-based materials always opens up opportunities for attempting to improve the properties available in the already known perovskites. During this Ph.D., different perovskite compounds Ln2−xMxMn2-yFeyO6-δ have been made, specifically in a search for new multiferroic materials. The materials studied in this project are: La1-xAxSrMn2O5+δ (with A =Ag and Li), LaBaMnFeO6-δ, LaBaMnFe0.5Zn0.5O6-δ, LaBaMnFe0.5Ti0.5O6-δ, LaBa0.5Ag0.5MnFeO6-δ and LaBa0.5Na0.5MnFeO6-δ, LaBaFe2O6-δ, LaBaFeTiO6-δ. However, after all properties have been measured, the compounds show either semiconductivity or conductivity, depending on the sample, next to a ferromagnetic transition, but no multiferroicity. To provide valuable knowledge for future searches for multiferroics, the Ph.D. study needs to be completed with the explanation why certain properties or present or absent. For this, we need to know the structures of the compounds, since the structure dictates the properties. However, the different techniques used so far all point to different structures, Mössbauer shows oxygen-vacancy order, X-ray diffraction shows disordered but undistorted perovskite and electron diffraction shows there has to be either some form of order or some kind of distortion. Therefore, the last step of this Ph.D. study is to explain these apparent contradictions (size effects ? defect structure ? ... ?) and solve the structure of the compounds, to be able to explain the properties. This last stage will be completed using the transmission electron microscopy facilities and crystallographic expertise present at the University of Antwerp.

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Improving the performance of rock salt type cathodes for Li-ion batteries through control of the transition metal cation migration using redox reactions of the oxygen sublattice and Li-conductive coatings. 01/01/2016 - 31/12/2019

Abstract

The performance of Li-ion batteries is still far below the threshold for automotive and grid applications. This largely depends on the cathode. The commercially most developed cathode is LiCoO2, but there is a better alternative in LiNixMnxCo1-2xO2(NMC). However, even the best NMC still suffers poor electrode kinetics and large voltage decays on cycling, due to structural rearrangements upon charge-discharge. We propose to engineer the reversibility of the structural transformation also in NMC by coupling the TM cation migration with redox changes at the oxygen sublattice through dedicated TM cation replacement. We also propose to develop a Li-ion conducting coating to prevent contact between electrolyte and cathode to stop oxygen and cation loss and improve the capacity retention.

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Controlling the bulk bandgap and phase transition in topological insulators by combining them with trivial insulators. 01/10/2015 - 30/09/2019

Abstract

Recently, the established division between insulators and conductors was torn down by the remarkable discovery of topological insulators. These materials are bulk insulating, but conducting at their surfaces. They receive a lot of attention for their exotic physics, interesting applications in spintronics and quantum computing and the creation of Majorana fermions (fermions that are their own antiparticles) in these materials. For the few known ones, we need better control over the band structure: most topological "insulators" are actually slightly bulk conducting. A way to tune this is through mixed crystals of topological and trivial (normal) insulators. These also allow to study the phase transition from topological to trivial insulator, for which the mechanism is controversial. So far, such mixed crystals were studied with techniques giving information on the average structure, but not the local structure. However, our preliminary data shows that local order between the different ions exists in several of these. Order will affect the electronic properties. We will study the local order in specific mixed crystals of topological – trivial insulators. We will use state-of-the-art transmission electron microscopy techniques which allow to pinpoint the positions and nature of the different ions at atomic scale. The solved structures will be used to calculate the electronic band structures using Density functional theory calculations. This gives us fundamental knowledge on the mechanism of the topological phase transition as well as the possibility to tune the electronic properties.

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Tailored oxide nanomaterials for regenerative fuel cells (NANO-MORF). 01/10/2015 - 30/09/2018

Abstract

Unitized regenerative fuel cells (URFCs) are currently attracting an increased attention as an emerging technology for storage and conversion of surplus electricity produced from renewable energy sources (solar, wind). In this context the challenge is to develop active, stable, and inexpensive electrocatalytic materials for the electrodes of URFCs. The objective of the project proposal is the design of advanced noble metal-free transition metal nano-oxides for the oxygen reduction (ORR) and oxygen evolution reaction (OER) in alkaline media in view of their application in URFCs. In order to achieve this goal we assemble an international interdisciplinary team and combine advanced characterization tools, synthesis, electrochemical methods, kinetic modeling, quantum and computational chemistry. The Russian team combines three groups working together for a long time. The Kazan group will use quantum chemical methods to predict catalytically active centers, and to calculate electron transfer rates. Using this information as an input, Moscow group will synthesize 3d-metal (Mn, Fe, Co and Ni) simple and complex nano-oxides and hydroxides by chemical methods. To better understand the role of defects, the Novosibirsk group will prepare long-lived metastable oxide nanostructures by electrodeposition. The Belgian partner will apply advanced transmission electron microscopy methods in order to access detailed information on the structure, chemical composition, cation distribution and coordination of the oxide nanoparticles in 2D and 3D. The French partner will investigate the electrochemical and electrocatalytic properties of the oxide nanoparticles, and develop kinetic models allowing to retrieve kinetic rate constants and adsorbate coverages, and provide feedback for further improvement of quantum chemical models. Achieving a molecular level understanding will allow us to design advanced oxide nanomaterials with high catalytic activities both in the ORR and OER.

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Functionalisation of nanostructured semiconductor metal oxides for chemical sensing (FONSENS). 01/10/2015 - 30/09/2018

Abstract

The objective of FONSENS is to develop breakthrough technologies in gas sensing that will provide higher sensitivity and superior selectivity at reduced cost and power consumption. This objective will be pursued by integrating complementary skills of EU and Russian groups. The main strategy in FONSENS for achieving enhanced sensor performances is to develop new nanostructured materials, which will allow control of concentration of active centers over a broad range for selective detection of toxic gases of different nature. The development of new generation of gas sensing materials will be supported by computational modeling with ab initio DFT calculations and a wide range of high resolution morphological and physico-chemical characterization techniques including (scanning) transmission electron microscopy and electron diffraction.

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InSol - Innovative Material Systems for Solar Energy Harvesting in Photoelectrochemical Cells. 01/07/2014 - 30/06/2017

Abstract

The project entitled "Innovative Material Systems for Solar Energy Harvesting in Photoelectrochemical Cells"(InSOL)" addresses the aspect of the 4th New Indigo Partnership Programme call on "New Material Systems for Renewable Energy". In this project, we aim to perform comprehensive theoretical and experimental investigations for the development of new graphene based earth-abundant material heterostructures for solar energy conversion through photoelectrochemical (PEC) cells. The key objective of this study is to identify new material combinations yielding high photon absorption and conversion efficiency under the constraint of using earth-abundant elements only. In a first step, ab-inito methods around Density Functional Theory (DFT) including the use of hybrid functionals will be used to screen promising material combinations with respect to their electronic and optical properties prior to actual device fabrication. Here, strategies will be developed how the single components with high performances in specific areas, for instance absorption of photons and conduction of charge carriers, can be combined to multi-material systems achieving the required overall functionality. The use of graphene as supporting material will provide an excellent electrical conductor for superior charge carrier drainage from the photoactive layers. In a second step, nano-heterostructures comprising earth abundant materials with superior visible-light activity will be developed by cost-effective wet chemical and gas phase methods. Of special importance in the proposed project is the engineering of the interfacial properties of the nano-heterostructures in order to obtain improved charge carrier separation and unhindered charge transport across the interfaces of the theoretically optimized materials. Therefore, the nano-heterostructures will be engineered through incorporation of conductive carbon nanostructures for facilitating interfacial charge carrier transport. The proposed studies on charge-transfer processes, chemical kinetics and photogenerated electron-hole pair recombination rates will synergize the hetero-contacts in the nano-catalyst and the electrical transport parameters. The structure and composition of the layers and interfaces will be monitored at atomic, nano and micrometer scale using transmission electron microscopy, providing information on the crystallographic phases and the crystallographic quality of the prepared samples. In a feedback loop the synthesis of the heterostructures will be adjusted according to the structural analysis such that optimal interface properties are achieved. The electrochemical characteristics of the hydrogen fuel forming photo-catalysts have to be analysed and related with their physical and structural properties. All of these data will be considered to elucidate the best performance for having the highest efficiency of the whole system. Regarding the big potential of solar energy conversion and the expected strong increase of the demand for clean energy worldwide this project also aims at fostering international collaboration that is highly appropriate in the field of solar energy materials due to its multidisciplinary character.

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TopSPIN for TEM nanostatistics. 19/05/2014 - 31/12/2018

Abstract

This project represents a formal research agreement between UA and on the other hand the Hercules Foundation. UA provides the Hercules Foundation research results mentioned in the title of the project under the conditions as stipulated in this contract.

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Precession electron diffraction for solving and refining the structure of materials, in particular for incommensurately modulated materials. 01/10/2011 - 28/02/2013

Abstract

The physical and chemical properties of materials are largely determined by the crystal structure of these materials. Therefore manipulating the crystal structure means altering and controlling the properties. The structure of most materials can be solved from X-ray diffraction (XRD) data. However, for nanomaterials or highly defective structures often electron diffraction (ED) data are the only data available. However, structure solution from ED data is classically very difficult and often impossible because the intensity of the reflections strongly depends on sample thickness, orientation, etc. Using Precession ED (PED) (recorded by precessing the beam on a cone) the data become less dependent of those factors, enabling the use of structure solution procedures developed for XRD on PED data. In order to obtain structure solution from single crystal XRD data, it was necessary to determine all factors influencing the data and incorporate their effect in the calculations. For PED all these factors now have to be figured out anew. In this project, the most important affecting factors and how to take them into account will be determined. The PED technique will also be generalized to n-dimensional space (calculations and software), so that it will be applicable for all crystals, including aperiodic crystals.

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Optimising the photoluminescence in scheelite-based materials through the incommensurate modulation of the cations. 01/01/2011 - 31/12/2014

Abstract

We will study the structure and optical properties of suitable new and old incommensurate scheelite based structures to determine this relation and optimize the optical properties by achieving the optimal cation arrangement.

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WeTCOat. 01/09/2010 - 30/09/2015

Abstract

The project WeTCOat aims at building generic knowledge in TCO precursor synthesis and formulation, film formation through wet deposition, thermal processes, annealing behaviour and their influence on the layers' performance in view of developing a cost effective, high throughput deposition technology for photovoltaic modules.

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PhyCIGS. 01/09/2010 - 31/08/2015

Abstract

The goal of the PhyCIGS project is to set up a spearhead knowledge based on thin film PV module production on the basis of breakthrough production technology by means of solution based processes based on CIGSSe chemistry.

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ABCIGS - Wet-processed CIGS based absorber layers for photovoltaic applications. 01/09/2010 - 30/09/2014

Abstract

The research aim of absCIGS is twofold. First, it aims at the development of a lab-scale non-vacuum baseline process for the formation of CIGS absorber layers, leading to cells with a conversion efficiency of 15%. Second, this work is complemented by the scientific understanding of the different steps in the process, running from the formation of the CIG5 precursors to the film transformation process. To achieve this, absCIGS sets great store by obtaining full control over the input/output relations, where the input is a dispersion of precursor nanoparticles (NPs) and the output is a dense CIGS TF.

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Multiferroics based on the Pb lone pair. 01/01/2009 - 31/12/2012

Abstract

The goal of this project is to realize and fully characterize new multiferroics. The chosen materials are based on the prediction of multiferroic properties in perovskite based oxides with A cations with a lone electron pair in combination with magnetic B cations. The lone pair will provide the ferroelectric properties, while the magnetic B-cations take care of the magnetic properties.

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Development of the possibility to refine incommensurately modulated materials from electron diffraction data. 01/07/2008 - 31/12/2012

Abstract

There are three main goals in this project: the optimisation of the practical implementation of precession electron diffraction on incommensurately modulated materials, the development of the software necessary for the treatment of these experimental results, and the application of the resulting new possibilities on hitherto unrefined materials.

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Synthesis, structure and properties of new low-dimensional manganites. 01/01/2006 - 31/12/2007

Abstract

A first goal of the project is to extend the knowledge on the complicated relationships between the chemical composition, crystal structure, local structure, electronic correlations and magnetic properties of complex oxides. As a second goal we want to develop modern synthesis paths towards new materials based on complex transition metal oxides with promising practical properties, in particular colossal magnetoresistance (CMR). The main steps to achieve this will be the synthesis of new compounds, the detailed structural investigation with various diffraction techniques including transmission electron microscopy (TEM), X-ray diffraction (XRD) and neutron diffraction (ND), and the characterization of the physical properties by magnetic and electric transport measurements. The choice of possible systems for investigation was based on crystal chemistry considerations, on known relationships between the crystal structure and the properties and on existing analogies with complex oxides of other transition metals.

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01/04/2003 - 31/12/2003

Abstract

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01/05/2002 - 30/04/2004

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