My research is focussed on studying the properties of materials and surface-adsorbate interfaces and processes taking place at these materials and interfaces. Important applications include photovoltaics and photocatalysis. We use a range of theoretical methods, mainly density-functional theory, and also charge transfer theory and molecular mechanics. Photovoltaics Photovoltaics uses solar cells to convert solar energy into electricity. Several types of solar cells have been developed; the current market leaders – silicon solar cells – are efficient but expensive. Alternative solar cell technologies are rapidly developing; in particular, solar cells based on perovskite materials have achieved excellent efficiencies, although their low stability remains a challenge. We study the properties of perovskite materials, in collaboration with the group of Prof. D. Lidzey in the Department of Physics. Photocatalysis Photocatalysis is a process which converts the energy of the Sun into the energy of chemical reactions. It has important current and potential applications, such as photocatalytic decomposition of pollutants in water and air, splitting of water into oxygen and hydrogen to produce "clean" environmentally friendly hydrogen fuel, and CO2 reduction which has the potential to clean up CO2 from the atmosphere and convert it to useful chemicals. We study various photocatalyst materials, such as graphitic carbon nitride, TiO2 and its composites with graphene-based materials, to evaluate their light absorption and electron-hole separation properties. We also study the interaction of TiO2 with pollutants in a collaborative project with Prof. S. Patwardhan in Chemical & Biological Engineering, to design new photocatalysts for water purification. Soil minerals/carbon interaction Soils contain large amounts of organic carbon, which is important both for capturing CO2 from the atmosphere, for growing crops, and more broadly for maintaining the stability of soils. However, carbon is being lost from soils because of the increase in intensive agriculture; it is therefore essential to keep replenishing the carbon content in soils. We are modelling the interaction of soil minerals with organic carbon, to identify organic molecular structures that bind most strongly to minerals in soil (with Al2O3 as a model mineral). The objective is to identify naturally abundant molecules or polymers suitable for adding to soil in agriculture. Molecular self-assembly Molecular self-assembly is a process whereby molecules assemble into ordered patterns, thanks to specific interactions between these molecules. These ordered structures have the potential to be used as building blocks in molecular electronics. However, to use them in any practical applications, we need to be able to understand and control their structures. We model the structures and dynamics of two-dimensional assemblies of organic molecules and metal-organic complexes on surfaces, in collaboration with the experimental group of M. Lackinger in Munich.