Understanding energy transformation in nanomaterials using absolutely localized electrons

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***A major challenge facing mankind in this century is the transition from fossil fuels to clean renewable energy sources. One of the most promising approaches to generate sufficient amount of energy on a global scale with minimal environmental impact is to convert the energy of sunlight into electricity and chemical fuels. Nanoscience offers an enormous potential for creating better materials for solar applications by taking advantage of new phenomena, which emerge as the size of structural material units approach the atomic scale.***The proposed research focuses on first-principle computational studies of basic steps of the conversion of solar energy into electricity and chemical fuels in nanomaterials: electron excitations, charge separation, photoinduced chemical reactions, and electrochemical processes. Its main objective is to reveal microscopic origins of several poorly understood and thus largely unexploited nanoscale effects that have a potential to greatly advance several important clean renewable energy technologies:**** Photovoltaics: multiple exciton generation in semiconductor nanostructures.**** Photocatalysis: tunable photoreduction of carbon dioxide to fuels, methanol and methane, on decorated nanoparticles.**** Electrochemistry: high-capacity energy storage at the charged interface between graphene and ionic liquids.***To overcome major obstacles that have severely limited first-principle computational studies of these processes a new class of electronic structure methods for nanoscale simulations will be developed. These methods will exploit a compact localized representation of electrons to provide two key advantages over the existing simulation techniques:***** an unprecedented computational efficiency of simulations in the ground and excited electronic states,***** a deep physical insight into fundamental relations between microscopic phenomena and observed properties of nanomaterials.***The proposed research will not only provide reliable quantitative characteristics of many important elementary energy conversion steps (e.g. rate constants, free energies), which can be directly related to key macroscopic properties of nanomaterials, but will also suggest new innovative strategies for engineering superior devices for clean renewable energy applications.***By utilizing advanced methods of quantum and statistical mechanics, modern tools of applied mathematics and recent achievements in high-performance computing, the research program is highly interdisciplinary. Its results will have a significant impact on computational design of materials in fundamental science including chemistry, physics, biology as well as in applied engineering disciplines.**