Computational modelling is used to predict photoelectrochemical properties of new dye molecules with the aim to find better dye molecules for use in solar energy conversion systems, including dye-sensitized solar cells and artificial photosynthesis. Electrochemical and photophysical properties are calculated from first principles for both organic dyes and metal complexes. Of particular relevance for the photoelectrochemical applications are predictions of new dyes that combine favourable light-harvesting capabilities, redox energies, and excited-state properties. The dye-sensitized solar cell calculations also include the use of model TiO₂ nanocrystals to investigate surface binding and interfacial electronic properties. Recent results for new dye molecules for both dye-sensitized solar cells and artificial photosynthesis will be presented, together with a general discussion of the emerging capabilities for atomistic calculations to guide the search for better solar energy conversion components.

The Figure shows a model interface of a dye-sensitized solar cell showing strong mixing of a ligand π* molecular orbital of a ruthenium dye with TiO₂ nanocrystal conduction band levels.