Title Promoter Affiliations Abstract "SOLARPAINT: Understanding the durability of light sensitive materials: transferring insights between solar cell physics and the chemistry of paintings." "Johan Verbeeck" "Condensed Matter Theory, AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation), Electron microscopy for materials research (EMAT)" "When light interacts with matter, it responds to this external stimulus in ways that depend on macroscopic properties but also on the microscopic details of the material. Pigments for instance, have a wavelength dependent reflection and absorption that causes the appearance of color in e.g. oil paintings. The absorption of light can also be used to capture the energy stored in solar light for use in photovoltaic solar cells. Perhaps surprisingly, the microscopic function of solar cells and pigments have a lot in common. Both absorb light and suffer from deterioration upon prolonged illumination and environmental conditions. This leads to chemical degradation (and altered colors) in historical paintings and to gradually reducing efficiencies in organic solar cells. In order to better understand their function and alteration behaviour, in this project, we propose to study in detail the microscopic origins of the capturing of light in heterogeneous materials found in oil paints and organic solar cells by combining state of the art experimental techniques based on synchrotron radiation and electron microscopy with advanced quantum mechanical models. This multidisciplinary approach will enable to improve the function and durability of future organic solar cells and will help to preserve and restore historical paintings from our cultural heritage." "A Boundary Modeling Scheme to Bridge the Computational Gap Between Classic Electrodynamics and Quantum Physics" "Guy Vandenbosch" "Waves: Core Research and Engineering (WaveCore)" "Classic Computational ElectroMagnetics (CEM), as the very technology modeling the interaction of EM waves with matter, has been demonstrated to be extremely successful in the progress of human kind. It can be seen as one of the enabling technologies realizing modern communication systems. Hence it is already greatly impacting peoples’ daily life. However, very recent deep-nanoscale experiments suggest the need for an entirely new way of modeling, making the bridge between classic CEM and quantum physics. A paradigm shift is thus necessary and a much more refined material model is required. Here, we address this problem by pioneering a boundary based modeling framework combining the dynamics of EM waves with the hydrodynamic motion of electrons. The proposed research can potentially bridge the computational gap between the macroscopic and the non-classical mesoscopic quantum world, also enabling a fully quantitative understanding of a wide range of new physical phenomena at nanometric scale. This may contribute to the solution of some of human kind’s global problems, just as classic CEM has done." "Identification of electrically active defects in materials for solar cells" "Henk Vrielinck" "Department of Solid State Sciences" "The purpose of this project is to identify defects in the absorber layer of solar cells, which limit the efficiency of the cells. The research focuses on thin film solar cells, mainly with CuIn(1-x)Ga(x)Se(2) absorber. Defects in solar cells and absorber bulk materials are characterized electrically, optically and structurally. The results of this reseach help directing the optimization of solar cells of this type." "BUKS2009 Workshop on MHD waves and seismology of the solar atmosphere." "Marcel Goossens" Plasma-astrophysics "6 research groups from Belgium, UK, and Spain (hence BUKS):The Solar Physics Group, Universitat de les Illes Balears, SpainThe Solar Physics and Space Plasma Research Centre, University of Sheffield, UKThe Solar and Magnetospheric Theory Group, University of St Andrews, UKThe Centre for Fusion, Space and Astrophysics, University of Warwick, UKThe Solar Physics department (SIDC) of the Royal Observatory of BelgiumThe Centre for Plasma Astrophysics, Katholieke Universiteit Leuven, Belgium have taken the initiative to organise an open and informal workshop on MHD waves and Seismology of the Solar Atmosphere. The aim is to exchange advanced results on observations, data-analysis, interpretation, modelling and seismology concerning MHD waves in the solar atmosphere and to discuss current open questions as well as required future research initiatives in this field. Invited keynote speakers are selected from outside of the 6 core groups, thereby helping to strengthen the cooperative efforts in this area of research. All groups active in this field are warmly welcomed to attend.." "Characterization and modelling of tandem solar cells and modules" "Bart VERMANG" "Materials Physics, Engineering Materials and Applications" "The heart of this PhD thesis is two-fold: (1) detailed optical, electrical and material characterization of the absorbers and fully fabricated devices, and (2) modelling of the device physics of tandem solar cells in different electrical configurations (i.e., 2, 3 and 4-terminal). Characterization techniques such as ellipsometry, X-ray diffraction, UV photoelectron spectroscopy, time-resolved photoluminescence (PL), PL quantum yield, and electrical will be used to gain insights into specific material or device properties. Simulation software such as Sunsolve and Sentaurus TCAD will be available to build a physics-based optoelectrical model of the tandem solar cells, based on the properties of the different layers and their interfaces. The developed models will be validated using functional devices, and subsequently used to analyze the main loss factors and suggest improvements to the device design. Comparison of the different electrical configurations would be done in both monofacial and bifacial modes, and configuration-dependent device optimization will be done. Gaining such insights into the device characteristics is key to boosting the performance of tandem solar cells." "Genetic Algorithms for modelling, simulation and optimization of 3D-photovoltaic networks for next generation solar cells" "Jean MANCA" "Materials Physics, Applied Computer Science Lab" "The introduction and development of genetic algorithms as optimization method can play an important role in the interdisciplinary domain of 'bulk heterojunction solar cells', a key concept for next generation solar cells, based on 3D interpenetrating photovoltaic networks of donor and acceptor nano-materials. These solar cells form an active interdisciplinary research domain, including materials chemistry, materials physics and engineering, but with a lack of appropriate support from the side of computational science. Ongoing research is already being done in the Institute of Materials Research at the Hasselt Universiy, as well as in the Theoretical Physics group from a more fundamental, thermodynamics viewpoint. In this project, these efforts will be extended to the development of a model which can readily be used in simulations. To be able to capture the required detail, such simulations will necessarily have to be fine-grained, calling for the use of state-of-the-art hardware (e.g. GPUs). Ultimately is the goal to be able to predict the behaviour of such 3D-nanostructured photovoltaic devices, so that their performance can be known before spending time and effort in actually building them. The final aspect is then the optimization of device characteristics, so that the efficiency of such devices can be enhanced." "Improving hybrid solar cells by controlled energy level alignment at donor-acceptor interfaces" "Hans-Gerd BOYEN" "Materials Physics" "Organic/inorganic (hybrid) solar cells pose a very eligible alternative for classical silicon based photovoltaics, both with respect to ease of production and cost. The most fundamental difference between these newer device types and silicon-based ones is that upon absorption of light, bound electron-hole pairs (or excitons) are created rather than free charge carriers. Hence, in order to extract charges from such a solar cell, the excitons have to split at the interface between the electron-donating and -accepting compound. Energy level alignment between this donor and acceptor is a pivotal element for high efficiency operation of the photovoltaic cell. Despite that several models have been proposed to explain this alignment in organic and hybrid devices, a conclusive picture of the underlying physics did not emerge. However, fundamental insight in the occurring interfacial effects is of paramount importance to outline universal design rules towards more efficient solar cells. Therefore, this project strives to study the energetics at metal-oxide/polymer interfaces during the preparing of appropriate hybrid solar cells, and to correlate the obtained results with photovoltaic parameters derived from the same devices. Energy levels at both sides of the donor-acceptor interface are manipulated and controlled in a systematic way by introducing additional molecular interlayers with varying dipolar moments. This will enable us to identify the key parameters determining the efficiency in such devices and, thus, help to push their performance to significantly higher values." "Crystalline organic thin films with large exciton diffusion lengths for high efficiency organic solar cells." "Andre Stesmans" "Semiconductor Physics, Informatics Section, ESAT - ELECTA, Electrical Energy and Computer Architectures, ESAT - MICAS, Microelectronics and Sensors" "In this project we want to establish a basis for a new generation of low-cost organic solar cells. Organic solar cells are made by deposition of organic semiconducting films, which in turn consist of several layers of organic (i.e. carbon-based) molecules. Usually, this deposition leads to the formation of amorphous or polycrystalline films. However, measurements on individually hand-picked organic single crystals show greatly improved charge carrier transport and exciton diffusion. We therefore set out to develop a process to deposit high-quality crystalline films with a process compatible with large scale solar cell production. As a starting point, we use an abrupt heating method which was developed for rubrene transistors. We already showed this method can produce crystalline rubrene thin films on several substrates, including the indium tin oxide covered glass substrate typically used for organic solar cells. In a next step, we will make these optically thin films thicker by growing extra, epitaxial layers of rubrene on top, and investigate the possibility to use these crystals as templates for crystalline heterojunctions. Furthermore, we will develop an understanding of crystalline film formation to generalize the process for materials other than rubrene.The resulting multi-crystalline films will be used to fundamentally investigate exciton diffusion, and will be integrated into high efficiency, state-of-the-art organic solar cells." "Preparation & Characterisation of Polymer:Fullerene Solar Cells" "Jean MANCA" "X-Lab, Materials Physics" "So-called organic solar cells, based on mixtures of conjugated polymers and fullerenes are promising next generation solar cells due to a multitude of specific advantages : they can be processed using traditional printing techniques, they can be prepared in different colours, shapes and on various (flexible) substrates (glass, plastic, paper,..),.. The general scope of this project is the preparation and characterization of polymer:fullerene solar cells based on a joint collaboration of complementary activities between Addis Ababa University and Hasselt University. Addis Ababa University has expertise in the synthesis of novel conjugated polymers and small molecules for solar cell applications and in this project will provide new isoindigo- and diketopyrrolopyrrole-based conjugated polymers and small molecules. Device preparation will occur both at Addis Ababa University (desk-top roll-to-roll) and at Hasselt University (spincoating in glovebox) and complementary characterisation will occur at both institutions. Due to this complementary collaboration, it is aimed to make a significant step forwards towards a better understanding and control of roll-to-roll printable solar cells." "Single-component organic solar cells: improved control over the polymer sequence toward enhanced device efficiency and lifetime" "Wouter MAES" "Materials Physics, Materials Chemistry" "Moving global energy consumption away from fossil fuels requires innovative renewable energy solutions. Photovoltaics (PV) can fulfill this need many times over if deployed over a large enough area. Despite being a promising thin-film PV technology – with particular advantages in terms of weight, aesthetics, and cost – organic photovoltaics have not witnessed a commercial breakthrough yet. Although the efficiency gap with inorganic thin-film PV has largely been closed, stability and reproducibility issues have not been fully resolved. Whereas the state-of-the-art organic solar cells employ physical mixtures of electron donor and acceptor components in bulk heterojunction active layers, recent initiatives put forward single-component organic solar cells wherein the donor and acceptor are chemically bonded in one material, thereby improving device stability and affording better industrial figures of merit. Nevertheless, the structures of the required all-conjugated donor-acceptor block copolymers are still poorly defined and the synthetic methods should be optimized to take full benefit of this novel approach. In the presented project, this challenge is addressed, strongly leaning on the synthetic and device expertise of the host research groups and using continuous flow chemistry to enhance control over the final polymer structures. The goal is to move beyond merely academic insights toward industrially relevant findings with a clear economic and societal added value."