Research
2016/17 Cycle
Optics Research
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Plasmonically Enhanced Upconversion of Solar Light from Anamorphic Concentrators
Photovoltaic solar conversion is a commercially available and widely used technology. We address several key issues on the road to more efficient utilization of the available solar power: - design small scale cost effective solar concentrators which can concentrate more in one direction at the expense of the orthogonal direction and are based on durable reflective optical elements; - develop upconversion of infrared to visible light readily absorbed in the solar cells and utilized for charge separation, thus increasing the fraction of usable solar spectrum; use nonlinear plasmonics and rationally designed metal nanocavities for enhancing the optical interaction of the nanocrystals developed for the spectral conversion.
Photovoltaics
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Understanding Structure-Property Relations in Organic-Inorganic Hybrid Perovskites from First Principles
Successful photovoltaic technology must combine high performance with low cost. Recently, organic-inorganic hybrid perovskites (OIHP), and especially methylammonium-lead-iodide (MAPbI3), have drawn enormous attention because they combine the outstanding semiconducting properties of inorganic semiconductors with the generally lower costs of organic crystals. However, little is known about defect behavior in these materials, and especially how its changes in time affect solar-cell performance and long-term stability. We aim to elucidate this behavior based on first-principles calculations, based on the atomic species involved and the laws of quantum mechanics. In such calculations, structural and chemical motifs can be created in a controlled manner and their properties examined systematically. This should afford a detailed understanding of mechanisms limiting cell performance and stability and therefore allow us to point out strategies for making further progress.
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Control over crystallization in hybrid organic/inorganic perovskite (HOIP) solar cells
The field of HOIP solar cells has experienced a meteoric rise due to spectacular efficiencies (above 20%), low cost and simple fabrication. However, one of the key questions, namely how the active layer is formed, is not well understood, leading to unreliable fabrication methodologies, and lack of a scientific basis needed to improve HOIP devices. We address the issue of understanding and control over HOIP formation using unique methodologies developed in our groups, as well as our complementary expertise. Our research will create a basis for rational design and the discovery of new types of HOIP materials.
Storage
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Shedding Light on Processes at the Electrode Interface in Lithium Ion Batteries by Dynamic Nuclear Polarization and Solid State NMR
Lithium ion batteries are a leading technology for storage of renewable energy and electric transportation. An important criterion for these applications is prolonged performance with high energy density. A major cause for premature battery failure is the electrode - electrolyte interactions, with the cathode being the main source for energy loss which is poorly understood. Our main goal here is to gain insight into the chemistry and mechanism of the interactions on the cathode side and their deleterious effect on the lifetime of battery cells. Such insight can then provide guidelines for developing more durable battery cells.
Biofuels
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Alternative Carbon Fixation Cycles for Increased Productivity and Sustainable Energy
Carbon fixation is the main pathway for storing energy and accumulating biomass in the living world. It also supplies our food and dominates humanity's usage of land and water. Under human cultivation, where water, light and nutrients can be abundant, it is the rate of carbon fixation that significantly limits growth. Hence increasing the rate of carbon fixation is of major importance in the path towards agricultural and energetic sustainability.We aim to construct and investigate a promising fully functional synthetic cycle for carbon fixation in the lab.
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Virus-inspired metabolic engineering of lipid content in marine algae
The world fossil oil reserves will be exhausted in less than 50 years. Therefore, renewable, carbon neutral, economically viable alternatives are urgently needed. The growing interest in microalgae for oil production is due to their relatively high lipid content and the new genetic and genomic resources that are currently available. We recently discovered that a marine algal virus has evolved unique metabolic strategies to infect its host by profoundly remodeling its lipid metabolism. Our overarching goal is to unfold some of the molecular secrets used during viral infection and mimic these metabolic principles to enhance lipid production for future biofuel application.
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Embedding Diverse Analytical Platforms in the Biofuel projects
Discovering of novel strategies for efficient biofuel production from renewable biomass sources is the main goal of biofuel research. The use of an analytical platform (so called 'metabolomics') for examining biomass composition, as for example lipid and carbohydrate content, is an elementary aspect of all biofuel projects. The fundamental objective is to employ cutting-edge analytical tools for the separation, detection, quantification and identification of biofuel-related compounds. This nationally unique, multi-platform analytical unit will provide advanced and complementary solutions for biofuel research in the AERI program.
Thermoelectric Power Conversion (TE)
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Atomic and molecular thermoelectricity: the role of vibrations and noise in heat pump-ing and heat to electric power conversion
Heat pumping and conversion of heat gradients to electric power (thermoelectricity) are fascinating schemes for sustainable energy. In particular, nanoscale conductors are attractive systems for such thermoelectric manipulations, due to their unique electronic and mechanical properties. However, it is not trivial to measure temperature at the nanoscale or control the parameters that promote thermoelectricity. We develop novel tools to probe the local temperature across metal-molecule-metal inter-faces (molecular junctions) to demonstrate heat-pumping and efficient thermoelectricity in unique structures of molecular junctions. We anticipate that this research will provide guidelines for efficient heat - electric power conversion.