Final Report Summary - ALIGN (Ab-initio computational modelling of photovoltaic interfaces) The goal of the project ALIGN was to develop and use quantum-mechanical atomistic simulation tools in order to understand and design advanced materials for photovoltaic energy conversion. The conversion of sunlight into electricity involves the absorption of photons by a semiconducting material, the generation of electrons and holes, and the their transport to the electrodes. In order to optimize current solar cells it is important to develop a detailed understanding of each of these steps at the atomic scale. In this project we have developed new quantum-mechanical methods for studying the energetics of electrons and holes in photovoltaic materials, we have introduced new techniques for studying the optical properties of photovoltaic materials under realistic temperature conditions, and we developed methods for performing predictive calculations of charge transport through metals and semiconductors. These developments are currently implemented in two open-source software projects, EPW, which is publicly available at http://epw.org.uk and SGW, which will be released shortly. These and other cutting-edge techniques were employed in order to investigate a variety of materials and their properties, including materials for dye-sensitized solar cells, organic/inorganic solar cells, quantum-dot sensitized solar cells, and hybrid organic-inorganic perovskite solar cells. One of the key achievements of the ALIGN project was the discovery of the first lead-free halide perovskites. What is remarkable about this discovery is that our computational predictions were subsequently confirmed by experiments, and led to the filing of a patent application. This finding, among the many other success stories of the ALIGN project, constitutes a prime example of the power of computational materials discovery and its increasing importance in the development of advanced energy materials.
